- import of strongswan-2.7.0

- applied patch for charon

234 files changed, 111313 insertions, 0 deletions

diff --git a/doc/.cvsignore b/doc/.cvsignore
new file mode 100644
index 000000000..a523b809d
--- /dev/null
+++ b/doc/.cvsignore
@@ -0,0 +1,66 @@
+HowTo.html
+HowTo.html
+adv_config.html
+adv_config.html
+background.html
+background.html
+biblio.html
+biblio.html
+compat.html
+compat.html
+config.html
+config.html
+draft-richardson-ipsec-opportunistic.nr
+draft-richardson-ipsec-rr.nr
+draft-richardson-ipsec-rr.txt
+faq.html
+faq.html
+firewall.html
+firewall.html
+glossary.html
+glossary.html
+index.html
+index.html
+install.html
+install.html
+interop.html
+interop.html
+intro.html
+intro.html
+ipsec.html
+ipsec.html
+kernel.html
+kernel.html
+mail.html
+mail.html
+makecheck.html
+manpage.d
+manpage.d
+manpages.html
+manpages.html
+multi_netjig.png
+nightly.html
+performance.html
+performance.html
+policygroups.html
+politics.html
+politics.html
+quickstart.html
+rfc.html
+rfc.html
+rfc_pg
+roadmap.html
+roadmap.html
+single_netjig.png
+testing.html
+testing.html
+toc.html
+toc.html
+trouble.html
+trouble.html
+umltesting.html
+upgrading.html
+user_examples.html
+user_examples.html
+web.html
+web.html
diff --git a/doc/2.6.known-issues b/doc/2.6.known-issues
new file mode 100644
index 000000000..397c4f957
--- /dev/null
+++ b/doc/2.6.known-issues
@@ -0,0 +1,112 @@
+Known issues with FreeS/WAN on a 2.6 kernel                   Claudia Schmeing
+-------------------------------------------
+
+
+This is an overview of known issues with FreeS/WAN on the 2.6 kernel codebase
+(also 2.5.x), which includes native Linux IPsec code.
+
+More information on the native IPsec code is available here:
+
+    http://lartc.org/howto/lartc.ipsec.html 
+
+Tools for use with that code are here:
+
+    http://ipsec-tools.sourceforge.net/
+
+
+* As of FreeS/WAN 2.03, FreeS/WAN ships with some support for the 2.6 kernel
+  IPsec code. In 2.03, this support is preliminary, but we expect to develop
+  it fully. Many thanks to Herbert Xu for the initial code patches.
+
+* Use the most recent Linux FreeS/WAN 2.x release from ftp.xs4all.nl 
+  to try our 2.6 kernel support.
+
+* The installation procedure for use with 2.6 kernel IPsec is a little 
+  different from a traditional FreeS/WAN installation. Please see
+  the latest doc/install.html.
+
+* Please see the design and users' mailing lists 
+  (http://www.freeswan.org/mail.html) for more detail and the latest reports.
+
+
+
+DESIGN-RELATED ISSUES
+
+
+* In 2.6, IPsec policies are detached from routing decisions. Because of this
+  design, Opportunistic Encryption on the local LAN will be possible with 2.6.
+
+  One side effect: When contacting a node on the local LAN which is protected
+  by gateway OE, you will get asymmetrical routing (one way through the gateway,
+  one way direct), and IPsec will drop the return packets.
+
+
+
+CURRENT ISSUES
+
+
+* For the moment, users wishing to test FreeS/WAN with 2.6 will require
+  ipsec-tools' "setkey" program. Though FreeS/WAN's keying daemon, Pluto,
+  directly sets IPsec policy, setkey is currently required to reset kernel SPD 
+  (Security Policy Database) states when Pluto restarts. We will likely add 
+  this basic functionality to an upcoming FreeS/WAN release.
+
+* State information is not available to the user, eg. ipsec 
+  eroute/ipsec spi/ipsec look do not work. The exception: ipsec auto --status 
+  This will be fixed in a future release.
+
+* If you're running Opportunistic Encryption, connectivity to new hosts will
+  immediately fail. You may receive a message similar to this:
+  
+     connect: Resource temporarily unavailable
+
+  The reason for this lies in the kernel code. Fairly complex discussion:
+
+      http://lists.freeswan.org/archives/design/2003-September/msg00073.html
+
+  As of 2.6.0-test6, this has not been fixed.
+
+* This initial connectivity failure has an unintended side effect on DNS queries. 
+  This will result in a rekey failure for OE connections; a %pass will be 
+  installed for your destination IP before a %pass is re-instituted to your 
+  DNS server. As a workaround, please add your DNS servers to 
+  /etc/ipsec.d/policies/clear. 
+
+* Packets on all interfaces are considered for OE, including loopback. If you're 
+  running a local nameserver, you'll still need to exempt localhost DNS traffic
+  as per the previous point. Since this traffic has a source of 127.0.0.1/32,
+  the "clear" policy group will not suffice; you'll need to add the following 
+  %passthrough conn to ipsec.conf:
+
+  conn exclude-lo
+          authby=never
+          left=127.0.0.1
+          leftsubnet=127.0.0.0/8
+          right=127.0.0.2
+          rightsubnet=127.0.0.0/8
+          type=passthrough
+          auto=route
+
+
+
+OLD ISSUES
+
+
+None, yet.
+
+
+
+RELATED DOCUMENTS
+
+
+FreeS/WAN Install web page        doc/install.html
+
+FreeS/WAN Install guide           INSTALL
+
+FreeS/WAN mailing list posts, including:
+
+    http://lists.freeswan.org/archives/design/2003-September/msg00057.html
+
+To sign up for our mailing lists, see http://www.freeswan.org/mail.html
+
+
diff --git a/doc/HowTo.html b/doc/HowTo.html
new file mode 100644
index 000000000..a6f92dda9
--- /dev/null
+++ b/doc/HowTo.html
@@ -0,0 +1,18733 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
+H5 { font-family: sans-serif }
+H6 { font-family: sans-serif }
+SUB { font-size: smaller }
+SUP { font-size: smaller }
+PRE { font-family: monospace }
+--></STYLE>
+</HEAD>
+<BODY>
+<CENTER><A HREF="#CONTENTS"><H1>Introduction to FreeS/WAN</H1></A><BR>
+</CENTER>
+<HR>
+<H1 ALIGN="CENTER"><A NAME="CONTENTS">Table of Contents</A></H1>
+<BR>
+<BR><B><A HREF="#intro">Introduction</A></B>
+<UL>
+<LI><A HREF="#ipsec.intro">IPsec, Security for the Internet Protocol</A></LI>
+<UL>
+<LI><A HREF="#intro.interop">Interoperating with other IPsec
+ implementations</A></LI>
+<LI><A HREF="#advantages">Advantages of IPsec</A></LI>
+<LI><A HREF="#applications">Applications of IPsec</A></LI>
+<UL>
+<LI><A HREF="#makeVPN">Using secure tunnels to create a VPN</A></LI>
+<LI><A HREF="#road.intro">Road Warriors</A></LI>
+<LI><A HREF="#opp.intro">Opportunistic encryption</A></LI>
+</UL>
+<LI><A HREF="#types">The need to authenticate gateways</A></LI>
+</UL>
+<LI><A HREF="#project">The FreeS/WAN project</A></LI>
+<UL>
+<LI><A HREF="#goals">Project goals</A></LI>
+<LI><A HREF="#staff">Project team</A></LI>
+</UL>
+<LI><A HREF="#products">Products containing FreeS/WAN</A></LI>
+<UL>
+<LI><A HREF="#distwith">Full Linux distributions</A></LI>
+<LI><A HREF="#kernel_dist">Linux kernel distributions</A></LI>
+<LI><A HREF="#office_dist">Office server distributions</A></LI>
+<LI><A HREF="#fw_dist">Firewall distributions</A></LI>
+<LI><A HREF="#turnkey">Firewall and VPN products</A></LI>
+</UL>
+<LI><A HREF="#docs">Information sources</A></LI>
+<UL>
+<LI><A HREF="#docformats">This HowTo, in multiple formats</A></LI>
+<LI><A HREF="#rtfm">RTFM (please Read The Fine Manuals)</A></LI>
+<LI><A HREF="#text">Other documents in the distribution</A></LI>
+<LI><A HREF="#assumptions">Background material</A></LI>
+<LI><A HREF="#archives">Archives of the project mailing list</A></LI>
+<LI><A HREF="#howto">User-written HowTo information</A></LI>
+<LI><A HREF="#applied">Papers on FreeS/WAN</A></LI>
+<LI><A HREF="#licensing">License and copyright information</A></LI>
+</UL>
+<LI><A HREF="#sites">Distribution sites</A></LI>
+<UL>
+<LI><A HREF="#1_5_1">Primary site</A></LI>
+<LI><A HREF="#mirrors">Mirrors</A></LI>
+<LI><A HREF="#munitions">The &quot;munitions&quot; archive of Linux crypto
+ software</A></LI>
+</UL>
+<LI><A HREF="#1_6">Links to other sections</A></LI>
+</UL>
+<B><A HREF="#2">Upgrading to FreeS/WAN 2.x</A></B>
+<UL>
+<LI><A HREF="#2_1">New! Built in Opportunistic connections</A></LI>
+<UL>
+<LI><A HREF="#2_1_1">Upgrading Opportunistic Encryption to 2.01 (or
+ later)</A></LI>
+</UL>
+<LI><A HREF="#2_2">New! Policy Groups</A></LI>
+<LI><A HREF="#2_3">New! Packetdefault Connection</A></LI>
+<LI><A HREF="#2_4">FreeS/WAN now disables Reverse Path Filtering</A></LI>
+<LI><A HREF="#2_5">Revised ipsec.conf</A></LI>
+<UL>
+<LI><A HREF="#2_5_1">No promise of compatibility</A></LI>
+<LI><A HREF="#2_5_2">Most ipsec.conf files will work fine</A></LI>
+<LI><A HREF="#2_5_3">Backward compatibility patch</A></LI>
+<LI><A HREF="#2_5_4">Details</A></LI>
+<LI><A HREF="#2_5_5">Upgrading from 1.x RPMs to 2.x RPMs</A></LI>
+</UL>
+</UL>
+<B><A HREF="#quickstart">Quickstart Guide to Opportunistic Encryption</A>
+</B>
+<UL>
+<LI><A HREF="#opp.setup">Purpose</A></LI>
+<UL>
+<LI><A HREF="#3_1_1">OE &quot;flag day&quot;</A></LI>
+</UL>
+<LI><A HREF="#opp.dns">Requirements</A></LI>
+<LI><A HREF="#easy.install">RPM install</A></LI>
+<UL>
+<LI><A HREF="#3_3_1">Download RPMs</A></LI>
+<LI><A HREF="#3_3_2">Check signatures</A></LI>
+<LI><A HREF="#3_3_3">Install the RPMs</A></LI>
+<LI><A HREF="#testinstall">Test</A></LI>
+</UL>
+<LI><A HREF="#opp.setups.list">Our Opportunistic Setups</A></LI>
+<UL>
+<LI><A HREF="#3_4_1">Full or partial opportunism?</A></LI>
+</UL>
+<LI><A HREF="#opp.client">Initiate-only setup</A></LI>
+<UL>
+<LI><A HREF="#3_5_1">Restrictions</A></LI>
+<LI><A HREF="#forward.dns">Create and publish a forward DNS record</A></LI>
+<UL>
+<LI><A HREF="#3_5_2_1">Find a domain you can use</A></LI>
+<LI><A HREF="#3_5_2_2">Choose your ID</A></LI>
+<LI><A HREF="#3_5_2_3">Create a forward TXT record</A></LI>
+<LI><A HREF="#3_5_2_4">Publish the forward TXT record</A></LI>
+</UL>
+<LI><A HREF="#3_5_3">Test that your key has been published</A></LI>
+<LI><A HREF="#3_5_4">Configure, if necessary</A></LI>
+<LI><A HREF="#3_5_5">Test</A></LI>
+</UL>
+<LI><A HREF="#3_6">Full Opportunism</A></LI>
+<UL>
+<LI><A HREF="#3_6_1">Put a TXT record in a Forward Domain</A></LI>
+<LI><A HREF="#3_6_2">Put a TXT record in Reverse DNS</A></LI>
+<UL>
+<LI><A HREF="#3_6_2_1">Create a Reverse DNS TXT record</A></LI>
+<LI><A HREF="#3_6_2_2">Publish your TXT record</A></LI>
+</UL>
+<LI><A HREF="#3_6_3">Test your DNS record</A></LI>
+<LI><A HREF="#3_6_4">No Configuration Needed</A></LI>
+<LI><A HREF="#3_6_5">Consider Firewalling</A></LI>
+<LI><A HREF="#3_6_6">Test</A></LI>
+<LI><A HREF="#3_6_7">Test</A></LI>
+</UL>
+<LI><A HREF="#opp.test">Testing opportunistic connections</A></LI>
+<LI><A HREF="#3_8">Now what?</A></LI>
+<LI><A HREF="#3_9">Notes</A></LI>
+<LI><A HREF="#3_10">Troubleshooting OE</A></LI>
+<LI><A HREF="#3_11">Known Issues</A></LI>
+</UL>
+<B><A HREF="#4">How to Configure Linux FreeS/WAN with Policy Groups</A></B>
+<UL>
+<LI><A HREF="#4_1">What are Policy Groups?</A></LI>
+<UL>
+<LI><A HREF="#4_1_1">Built-In Security Options</A></LI>
+</UL>
+<LI><A HREF="#4_2">Using Policy Groups</A></LI>
+<UL>
+<LI><A HREF="#4_2_1">Example 1: Using a Base Policy Group</A></LI>
+<LI><A HREF="#4_2_2">Example 2: Defining IPsec Security Policy with
+ Groups</A></LI>
+<LI><A HREF="#4_2_3">Example 3: Creating a Simple IPsec VPN with the
+ private Group</A></LI>
+<LI><A HREF="#4_2_4">Example 4: New Policy Groups to Protect a Subnet</A>
+</LI>
+<LI><A HREF="#4_2_5">Example 5: Adding a Subnet to the VPN</A></LI>
+</UL>
+<LI><A HREF="#4_3">Appendix</A></LI>
+<UL>
+<LI><A HREF="#4_3_1">Our Hidden Connections</A></LI>
+<LI><A HREF="#4_3_2">Custom Policy Groups</A></LI>
+<LI><A HREF="#4_3_3">Disabling Opportunistic Encryption</A></LI>
+</UL>
+</UL>
+<B><A HREF="#5">FreeS/WAN FAQ</A></B>
+<UL>
+<LI><A HREF="#questions">Index of FAQ questions</A></LI>
+<LI><A HREF="#whatzit">What is FreeS/WAN?</A></LI>
+<LI><A HREF="#problems">How do I report a problem or seek help?</A></LI>
+<LI><A HREF="#generic">Can I get ...</A></LI>
+<UL>
+<LI><A HREF="#lemme_out">Can I get an off-the-shelf system that includes
+ FreeS/WAN?</A></LI>
+<LI><A HREF="#consultant">Can I hire consultants or staff who know
+ FreeS/WAN?</A></LI>
+<LI><A HREF="#commercial">Can I get commercial support?</A></LI>
+</UL>
+<LI><A HREF="#release">Release questions</A></LI>
+<UL>
+<LI><A HREF="#rel.current">What is the current release?</A></LI>
+<LI><A HREF="#relwhen">When is the next release?</A></LI>
+<LI><A HREF="#rel.bugs">Are there known bugs in the current release?</A></LI>
+</UL>
+<LI><A HREF="#mod_cons">Modifications and contributions</A></LI>
+<UL>
+<LI><A HREF="#modify.faq">Can I modify FreeS/WAN to ...?</A></LI>
+<LI><A HREF="#contrib.faq">Can I contribute to the project?</A></LI>
+<LI><A HREF="#ddoc.faq">Is there detailed design documentation?</A></LI>
+</UL>
+<LI><A HREF="#interact">Will FreeS/WAN work in my environment?</A></LI>
+<UL>
+<LI><A HREF="#interop.faq">Can FreeS/WAN talk to ...?</A></LI>
+<LI><A HREF="#old_to_new">Can different FreeS/WAN versions talk to each
+ other?</A></LI>
+<LI><A HREF="#faq.bandwidth">Is there a limit on throughput?</A></LI>
+<LI><A HREF="#faq.number">Is there a limit on number of tunnels?</A></LI>
+<LI><A HREF="#faq.speed">Is a ... fast enough to handle FreeS/WAN with
+ my loads?</A></LI>
+</UL>
+<LI><A HREF="#work_on">Will FreeS/WAN work on ... ?</A></LI>
+<UL>
+<LI><A HREF="#versions">Will FreeS/WAN run on my version of Linux?</A></LI>
+<LI><A HREF="#nonIntel.faq">Will FreeS/WAN run on non-Intel CPUs?</A></LI>
+<LI><A HREF="#multi.faq">Will FreeS/WAN run on multiprocessors?</A></LI>
+<LI><A HREF="#k.old">Will FreeS/WAN work on an older kernel?</A></LI>
+<LI><A HREF="#k.versions">Will FreeS/WAN run on the latest kernel
+ version?</A></LI>
+<LI><A HREF="#interface.faq">Will FreeS/WAN work on unusual network
+ hardware?</A></LI>
+<LI><A HREF="#vlan">Will FreeS/WAN work on a VLAN (802.1q) network?</A></LI>
+</UL>
+<LI><A HREF="#features.faq">Does FreeS/WAN support ...</A></LI>
+<UL>
+<LI><A HREF="#VPN.faq">Does FreeS/WAN support site-to-site VPN (Virtual
+ Private Network) applications?</A></LI>
+<LI><A HREF="#warrior.faq">Does FreeS/WAN support remote users
+ connecting to a LAN?</A></LI>
+<LI><A HREF="#road.shared.possible">Does FreeS/WAN support remote users
+ using shared secret authentication?</A></LI>
+<LI><A HREF="#wireless.faq">Does FreeS/WAN support wireless networks?</A>
+</LI>
+<LI><A HREF="#PKIcert">Does FreeS/WAN support X.509 or other PKI
+ certificates?</A></LI>
+<LI><A HREF="#Radius">Does FreeS/WAN support user authentication
+ (Radius, SecureID, Smart Card...)?</A></LI>
+<LI><A HREF="#NATtraversal">Does FreeS/WAN support NAT traversal?</A></LI>
+<LI><A HREF="#virtID">Does FreeS/WAN support assigning a &quot;virtual
+ identity&quot; to a remote system?</A></LI>
+<LI><A HREF="#noDES.faq">Does FreeS/WAN support single DES encryption?</A>
+</LI>
+<LI><A HREF="#AES.faq">Does FreeS/WAN support AES encryption?</A></LI>
+<LI><A HREF="#other.cipher">Does FreeS/WAN support other encryption
+ algorithms?</A></LI>
+</UL>
+<LI><A HREF="#canI">Can I ...</A></LI>
+<UL>
+<LI><A HREF="#policy.preconfig">Can I use policy groups along with
+ explicitly configured connections?</A></LI>
+<LI><A HREF="#policy.off">Can I turn off policy groups?</A></LI>
+<LI><A HREF="#reload">Can I reload connection info without restarting?</A>
+</LI>
+<LI><A HREF="#masq.faq">Can I use several masqueraded subnets?</A></LI>
+<LI><A HREF="#dup_route">Can I use subnets masqueraded to the same
+ addresses?</A></LI>
+<LI><A HREF="#road.masq">Can I assign a road warrior an address on my
+ net (a virtual identity)?</A></LI>
+<LI><A HREF="#road.many">Can I support many road warriors with one
+ gateway?</A></LI>
+<LI><A HREF="#road.PSK">Can I have many road warriors using shared
+ secret authentication?</A></LI>
+<LI><A HREF="#QoS">Can I use Quality of Service routing with FreeS/WAN?</A>
+</LI>
+<LI><A HREF="#deadtunnel">Can I recognise dead tunnels and shut them
+ down?</A></LI>
+<LI><A HREF="#demanddial">Can I build IPsec tunnels over a demand-dialed
+ link?</A></LI>
+<LI><A HREF="#GRE">Can I build GRE, L2TP or PPTP tunnels over IPsec?</A></LI>
+<LI><A HREF="#NetBIOS">... use Network Neighborhood (Samba, NetBIOS)
+ over IPsec?</A></LI>
+</UL>
+<LI><A HREF="#setup.faq">Life's little mysteries</A></LI>
+<UL>
+<LI><A HREF="#cantping">I cannot ping ....</A></LI>
+<LI><A HREF="#forever">It takes forever to ...</A></LI>
+<LI><A HREF="#route">I send packets to the tunnel with route(8) but they
+ vanish</A></LI>
+<LI><A HREF="#down_route">When a tunnel goes down, packets vanish</A></LI>
+<LI><A HREF="#firewall_ate">The firewall ate my packets!</A></LI>
+<LI><A HREF="#dropconn">Dropped connections</A></LI>
+<LI><A HREF="#defaultroutegone">Disappearing %defaultroute</A></LI>
+<LI><A HREF="#tcpdump.faq">TCPdump on the gateway shows strange things</A>
+</LI>
+<LI><A HREF="#no_trace">Traceroute does not show anything between the
+ gateways</A></LI>
+</UL>
+<LI><A HREF="#man4debug">Testing in stages</A></LI>
+<UL>
+<LI><A HREF="#nomanual">Manually keyed connections don't work</A></LI>
+<LI><A HREF="#spi_error">One manual connection works, but second one
+ fails</A></LI>
+<LI><A HREF="#man_no_auto">Manual connections work, but automatic keying
+ doesn't</A></LI>
+<LI><A HREF="#nocomp">IPsec works, but connections using compression
+ fail</A></LI>
+<LI><A HREF="#pmtu.broken">Small packets work, but large transfers fail</A>
+</LI>
+<LI><A HREF="#subsub">Subnet-to-subnet works, but tests from the
+ gateways don't</A></LI>
+</UL>
+<LI><A HREF="#compile.faq">Compilation problems</A></LI>
+<UL>
+<LI><A HREF="#gmp.h_missing">gmp.h: No such file or directory</A></LI>
+<LI><A HREF="#noVM">... virtual memory exhausted</A></LI>
+</UL>
+<LI><A HREF="#error">Interpreting error messages</A></LI>
+<UL>
+<LI><A HREF="#route-client">route-client (or host) exited with status 7</A>
+</LI>
+<LI><A HREF="#unreachable">SIOCADDRT:Network is unreachable</A></LI>
+<LI><A HREF="#modprobe">ipsec_setup: modprobe: Can't locate module ipsec</A>
+</LI>
+<LI><A HREF="#noKLIPS">ipsec_setup: Fatal error, kernel appears to lack
+ KLIPS</A></LI>
+<LI><A HREF="#noDNS">ipsec_setup: ... failure to fetch key for ... from
+ DNS</A></LI>
+<LI><A HREF="#dup_address">ipsec_setup: ... interfaces ... and ... share
+ address ...</A></LI>
+<LI><A HREF="#kflags">ipsec_setup: Cannot adjust kernel flags</A></LI>
+<LI><A HREF="#message_num">Message numbers (MI3, QR1, et cetera) in
+ Pluto messages</A></LI>
+<LI><A HREF="#conn_name">Connection names in Pluto error messages</A></LI>
+<LI><A HREF="#cantorient">Pluto: ... can't orient connection</A></LI>
+<LI><A HREF="#no.interface">... we have no ipsecN interface for either
+ end of this connection</A></LI>
+<LI><A HREF="#noconn">Pluto: ... no connection is known</A></LI>
+<LI><A HREF="#nosuit">Pluto: ... no suitable connection ...</A></LI>
+<LI><A HREF="#noconn.auth">Pluto: ... no connection has been authorized</A>
+</LI>
+<LI><A HREF="#noDESsupport">Pluto: ... OAKLEY_DES_CBC is not supported.</A>
+</LI>
+<LI><A HREF="#notransform">Pluto: ... no acceptable transform</A></LI>
+<LI><A HREF="#rsasigkey">rsasigkey dumps core</A></LI>
+<LI><A HREF="#sig4">!Pluto failure!: ... exited with ... signal 4</A></LI>
+<LI><A HREF="#econnrefused">ECONNREFUSED error message</A></LI>
+<LI><A HREF="#no_eroute">klips_debug: ... no eroute!</A></LI>
+<LI><A HREF="#SAused">... trouble writing to /dev/ipsec ... SA already
+ in use</A></LI>
+<LI><A HREF="#ignore">... ignoring ... payload</A></LI>
+<LI><A HREF="#unknown_rightcert">unknown parameter name &quot;rightcert&quot;</A></LI>
+</UL>
+<LI><A HREF="#spam">Why don't you restrict the mailing lists to reduce
+ spam?</A></LI>
+</UL>
+<B><A HREF="#manpages">FreeS/WAN manual pages</A></B>
+<UL>
+<LI><A HREF="#man.file">Files</A></LI>
+<LI><A HREF="#man.command">Commands</A></LI>
+<LI><A HREF="#man.lib">Library routines</A></LI>
+</UL>
+<B><A HREF="#firewall">FreeS/WAN and firewalls</A></B>
+<UL>
+<LI><A HREF="#filters">Filtering rules for IPsec packets</A></LI>
+<LI><A HREF="#examplefw">Firewall configuration at boot</A></LI>
+<UL>
+<LI><A HREF="#simple.rules">A simple set of rules</A></LI>
+<LI><A HREF="#complex.rules">Other rules</A></LI>
+<UL>
+<LI><A HREF="#7_2_2_1">Adding additional rules</A></LI>
+<LI><A HREF="#7_2_2_2">Modifying existing rules</A></LI>
+</UL>
+<LI><A HREF="#rules.pub">Published rule sets</A></LI>
+<UL>
+<LI><A HREF="#Ranch.trinity">Scripts based on Ranch's work</A></LI>
+<LI><A HREF="#seawall">The Seattle firewall</A></LI>
+<LI><A HREF="#rcf">The RCF scripts</A></LI>
+<LI><A HREF="#asgard">Asgard scripts</A></LI>
+<LI><A HREF="#user.scripts">User scripts from the mailing list</A></LI>
+</UL>
+</UL>
+<LI><A HREF="#updown">Calling firewall scripts, named in ipsec.conf(5)</A>
+</LI>
+<UL>
+<LI><A HREF="#pre_post">Scripts called at IPsec start and stop</A></LI>
+<LI><A HREF="#up_down">Scripts called at connection up and down</A></LI>
+<UL>
+<LI><A HREF="#fw.default">The default script</A></LI>
+<LI><A HREF="#userscript">User-written scripts</A></LI>
+</UL>
+<LI><A HREF="#ipchains.script">Scripts for ipchains or iptables</A></LI>
+</UL>
+<LI><A HREF="#NAT">A complication: IPsec vs. NAT</A></LI>
+<UL>
+<LI><A HREF="#nat_ok">NAT on or behind the IPsec gateway works</A></LI>
+<LI><A HREF="#nat_bad">NAT between gateways is problematic</A></LI>
+<LI><A HREF="#NAT.ref">Other references on NAT and IPsec</A></LI>
+</UL>
+<LI><A HREF="#complications">Other complications</A></LI>
+<UL>
+<LI><A HREF="#through">IPsec through the gateway</A></LI>
+<LI><A HREF="#ipsec_only">Preventing non-IPsec traffic</A></LI>
+<LI><A HREF="#unknowngate">Filtering packets from unknown gateways</A></LI>
+</UL>
+<LI><A HREF="#otherfilter">Other packet filters</A></LI>
+<UL>
+<LI><A HREF="#ICMP">ICMP filtering</A></LI>
+<LI><A HREF="#traceroute">UDP packets for traceroute</A></LI>
+<LI><A HREF="#l2tp">UDP for L2TP</A></LI>
+</UL>
+<LI><A HREF="#packets">How it all works: IPsec packet details</A></LI>
+<UL>
+<LI><A HREF="#noport">ESP and AH do not have ports</A></LI>
+<LI><A HREF="#header">Header layout</A></LI>
+<LI><A HREF="#dhr">DHR on the updown script</A></LI>
+</UL>
+</UL>
+<B><A HREF="#trouble">Linux FreeS/WAN Troubleshooting Guide</A></B>
+<UL>
+<LI><A HREF="#overview">Overview</A></LI>
+<LI><A HREF="#install">1. During Install</A></LI>
+<UL>
+<LI><A HREF="#8_2_1">1.1 RPM install gotchas</A></LI>
+<LI><A HREF="#8_2_2">1.2 Problems installing from source</A></LI>
+<LI><A HREF="#install.check">1.3 Install checks</A></LI>
+<LI><A HREF="#oe.trouble">1.3 Troubleshooting OE</A></LI>
+</UL>
+<LI><A HREF="#negotiation">2. During Negotiation</A></LI>
+<UL>
+<LI><A HREF="#state">2.1 Determine Connection State</A></LI>
+<UL>
+<LI><A HREF="#8_3_1_1">Finding current state</A></LI>
+<LI><A HREF="#8_3_1_2">What's this supposed to look like?</A></LI>
+</UL>
+<LI><A HREF="#find.pluto.error">2.2 Finding error text</A></LI>
+<UL>
+<LI><A HREF="#8_3_2_1">Verbose start for more information</A></LI>
+<LI><A HREF="#8_3_2_2">Debug levels count</A></LI>
+<LI><A HREF="#8_3_2_3">ipsec barf for lots of debugging information</A></LI>
+<LI><A HREF="#8_3_2_4">Find the error</A></LI>
+<LI><A HREF="#8_3_2_5">Play both sides</A></LI>
+</UL>
+<LI><A HREF="#interpret.pluto.error">2.3 Interpreting a Negotiation
+ Error</A></LI>
+<UL>
+<LI><A HREF="#ikepath">Connection stuck at STATE_MAIN_I1</A></LI>
+<LI><A HREF="#8_3_3_2">Other errors</A></LI>
+</UL>
+</UL>
+<LI><A HREF="#use">3. Using a Connection</A></LI>
+<UL>
+<LI><A HREF="#8_4_1">3.1 Orienting yourself</A></LI>
+<UL>
+<LI><A HREF="#8_4_1_1">How do I know if it works?</A></LI>
+<LI><A HREF="#8_4_1_2">ipsec barf is useful again</A></LI>
+</UL>
+<LI><A HREF="#8_4_2">3.2 Those pesky configuration errors</A></LI>
+<LI><A HREF="#route.firewall">3.3 Check Routing and Firewalling</A></LI>
+<UL>
+<LI><A HREF="#8_4_3_1">Background:</A></LI>
+<LI><A HREF="#ifconfig">View Interface and Firewall Statistics</A></LI>
+</UL>
+<LI><A HREF="#sniff">3.4 When in doubt, sniff it out</A></LI>
+<UL>
+<LI><A HREF="#8_4_4_1">Anticipate your packets' path</A></LI>
+</UL>
+<LI><A HREF="#find.use.error">3.5 Check your logs</A></LI>
+<UL>
+<LI><A HREF="#interpret.use.error">Interpreting log text</A></LI>
+</UL>
+<LI><A HREF="#bigpacket">3.6 More testing for the truly thorough</A></LI>
+<UL>
+<LI><A HREF="#8_4_6_1">Large Packets</A></LI>
+<LI><A HREF="#8_4_6_2">Stress Tests</A></LI>
+</UL>
+</UL>
+<LI><A HREF="#prob.report">4. Problem Reporting</A></LI>
+<UL>
+<LI><A HREF="#8_5_1">4.1 How to ask for help</A></LI>
+<LI><A HREF="#8_5_2">4.2 Where to ask</A></LI>
+</UL>
+<LI><A HREF="#notes">5. Additional Notes on Troubleshooting</A></LI>
+<UL>
+<LI><A HREF="#system.info">5.1 Information available on your system</A></LI>
+<UL>
+<LI><A HREF="#logusage">Logs used</A></LI>
+<LI><A HREF="#pages">man pages provided</A></LI>
+<LI><A HREF="#statusinfo">Status information</A></LI>
+</UL>
+<LI><A HREF="#testgates"> 5.2 Testing between security gateways</A></LI>
+<LI><A HREF="#ifconfig1">5.3 ifconfig reports for KLIPS debugging</A></LI>
+<LI><A HREF="#gdb"> 5.4 Using GDB on Pluto</A></LI>
+</UL>
+</UL>
+<B><A HREF="#compat">Linux FreeS/WAN Compatibility Guide</A></B>
+<UL>
+<LI><A HREF="#spec">Implemented parts of the IPsec Specification</A></LI>
+<UL>
+<LI><A HREF="#in">In Linux FreeS/WAN</A></LI>
+<LI><A HREF="#dropped">Deliberately omitted</A></LI>
+<LI><A HREF="#not">Not (yet) in Linux FreeS/WAN</A></LI>
+</UL>
+<LI><A HREF="#pfkey">Our PF-Key implementation</A></LI>
+<UL>
+<LI><A HREF="#pfk.port">PF-Key portability</A></LI>
+</UL>
+<LI><A HREF="#otherk">Kernels other than the latest 2.2.x and 2.4.y</A></LI>
+<UL>
+<LI><A HREF="#kernel.2.0">2.0.x kernels</A></LI>
+<LI><A HREF="#kernel.production">2.2 and 2.4 kernels</A></LI>
+</UL>
+<LI><A HREF="#otherdist">Intel Linux distributions other than Redhat</A></LI>
+<UL>
+<LI><A HREF="#rh7">Redhat 7.0</A></LI>
+<LI><A HREF="#suse">SuSE Linux</A></LI>
+<UL>
+<LI><A HREF="#9_4_2_1">SuSE Linux 5.3</A></LI>
+</UL>
+<LI><A HREF="#slack">Slackware</A></LI>
+<LI><A HREF="#deb">Debian</A></LI>
+<LI><A HREF="#caldera">Caldera</A></LI>
+</UL>
+<LI><A HREF="#CPUs">CPUs other than Intel</A></LI>
+<UL>
+<LI><A HREF="# strongarm">Corel Netwinder (StrongARM CPU)</A></LI>
+<LI><A HREF="#yellowdog">Yellow Dog Linux on Power PC</A></LI>
+<LI><A HREF="#mklinux">Mklinux</A></LI>
+<LI><A HREF="#alpha">Alpha 64-bit processors</A></LI>
+<LI><A HREF="#SPARC">Sun SPARC processors</A></LI>
+<LI><A HREF="#mips">MIPS processors</A></LI>
+<LI><A HREF="#crusoe">Transmeta Crusoe</A></LI>
+<LI><A HREF="#coldfire">Motorola Coldfire</A></LI>
+</UL>
+<LI><A HREF="#multiprocessor">Multiprocessor machines</A></LI>
+<LI><A HREF="#hardware">Support for crypto hardware</A></LI>
+<LI><A HREF="#ipv6">IP version 6 (IPng)</A></LI>
+<UL>
+<LI><A HREF="#v6.back">IPv6 background</A></LI>
+</UL>
+</UL>
+<B><A HREF="#10">Interoperating with FreeS/WAN</A></B>
+<UL>
+<LI><A HREF="#10_1">Interop at a Glance</A></LI>
+<UL>
+<LI><A HREF="#10_1_1">Key</A></LI>
+</UL>
+<LI><A HREF="#10_2">Basic Interop Rules</A></LI>
+<LI><A HREF="#10_3">Longer Stories</A></LI>
+<UL>
+<LI><A HREF="#10_3_1">For More Compatible Implementations</A></LI>
+<UL>
+<LI><A HREF="#freeswan">FreeS/WAN</A></LI>
+<LI><A HREF="#isakmpd">isakmpd (OpenBSD)</A></LI>
+<LI><A HREF="#kame">Kame</A></LI>
+<LI><A HREF="#mcafee">PGPNet/McAfee</A></LI>
+<LI><A HREF="#microsoft">Microsoft Windows 2000/XP</A></LI>
+<LI><A HREF="#ssh">SSH Sentinel</A></LI>
+<LI><A HREF="#safenet">Safenet SoftPK/SoftRemote</A></LI>
+</UL>
+<LI><A HREF="#10_3_2">For Other Implementations</A></LI>
+<UL>
+<LI><A HREF="#6wind">6Wind</A></LI>
+<LI><A HREF="#alcatel">Alcatel Timestep</A></LI>
+<LI><A HREF="#apple">Apple Macintosh System 10+</A></LI>
+<LI><A HREF="#ashleylaurent">AshleyLaurent VPCom</A></LI>
+<LI><A HREF="#borderware">Borderware</A></LI>
+<LI><A HREF="#checkpoint">Check Point VPN-1 or FW-1</A></LI>
+<LI><A HREF="#cisco">Cisco</A></LI>
+<LI><A HREF="#equinux">Equinux VPN tracker (for Mac OS X)</A></LI>
+<LI><A HREF="#fsecure">F-Secure</A></LI>
+<LI><A HREF="#gauntlet">Gauntlet GVPN</A></LI>
+<LI><A HREF="#aix">IBM AIX</A></LI>
+<LI><A HREF="#as400">IBM AS/400</A></LI>
+<LI><A HREF="#intel">Intel Shiva LANRover / Net Structure</A></LI>
+<LI><A HREF="#lancom">LanCom (formerly ELSA)</A></LI>
+<LI><A HREF="#linksys">Linksys</A></LI>
+<LI><A HREF="#lucent">Lucent</A></LI>
+<LI><A HREF="#netasq">Netasq</A></LI>
+<LI><A HREF="#netcelo">Netcelo</A></LI>
+<LI><A HREF="#netgear">Netgear fvs318</A></LI>
+<LI><A HREF="#netscreen">Netscreen 100 or 5xp</A></LI>
+<LI><A HREF="#nortel">Nortel Contivity</A></LI>
+<LI><A HREF="#radguard">Radguard</A></LI>
+<LI><A HREF="#raptor">Raptor (NT or Solaris)</A></LI>
+<LI><A HREF="#redcreek">Redcreek Ravlin</A></LI>
+<LI><A HREF="#sonicwall">SonicWall</A></LI>
+<LI><A HREF="#sun">Sun Solaris</A></LI>
+<LI><A HREF="#symantec">Symantec</A></LI>
+<LI><A HREF="#watchguard">Watchguard Firebox</A></LI>
+<LI><A HREF="#xedia">Xedia Access Point/QVPN</A></LI>
+<LI><A HREF="#zyxel">Zyxel</A></LI>
+</UL>
+</UL>
+</UL>
+<B><A HREF="#performance">Performance of FreeS/WAN</A></B>
+<UL>
+<LI><A HREF="#pub.bench">Published material</A></LI>
+<LI><A HREF="#perf.estimate">Estimating CPU overheads</A></LI>
+<UL>
+<LI><A HREF="#perf.more">Higher performance alternatives</A></LI>
+<LI><A HREF="#11_2_2">Other considerations</A></LI>
+</UL>
+<LI><A HREF="#biggate">Many tunnels from a single gateway</A></LI>
+<LI><A HREF="#low-end">Low-end systems</A></LI>
+<LI><A HREF="#klips.bench">Measuring KLIPS</A></LI>
+<LI><A HREF="#speed.compress">Speed with compression</A></LI>
+<LI><A HREF="#methods">Methods of measuring</A></LI>
+</UL>
+<B><A HREF="#test.freeswan">Testing FreeS/WAN</A></B>
+<UL>
+<LI><A HREF="#test.oe">Testing opportunistic connections</A></LI>
+<UL>
+<LI><A HREF="#12_1_1">Basic OE Test</A></LI>
+<LI><A HREF="#12_1_2">OE Gateway Test</A></LI>
+<LI><A HREF="#12_1_3">Additional OE tests</A></LI>
+</UL>
+<LI><A HREF="#test.uml">Testing with User Mode Linux</A></LI>
+<LI><A HREF="#testnet">Configuration for a testbed network</A></LI>
+<UL>
+<LI><A HREF="#testbed">Testbed network</A></LI>
+<LI><A HREF="#tcpdump.test">Using packet sniffers in testing</A></LI>
+</UL>
+<LI><A HREF="#verify.crypt">Verifying encryption</A></LI>
+<LI><A HREF="#mail.test">Mailing list pointers</A></LI>
+</UL>
+<B><A HREF="#kernelconfig">Kernel configuration for FreeS/WAN</A></B>
+<UL>
+<LI><A HREF="#notall">Not everyone needs to worry about kernel
+ configuration</A></LI>
+<LI><A HREF="#assume">Assumptions and notation</A></LI>
+<UL>
+<LI><A HREF="#labels">Labels used</A></LI>
+</UL>
+<LI><A HREF="#kernelopt">Kernel options for FreeS/WAN</A></LI>
+</UL>
+<B><A HREF="#adv_config">Other configuration possibilities</A></B>
+<UL>
+<LI><A HREF="#thumb">Some rules of thumb about configuration</A></LI>
+<UL>
+<LI><A HREF="#cheap.tunnel">Tunnels are cheap</A></LI>
+<LI><A HREF="#subnet.size">Subnet sizes</A></LI>
+<LI><A HREF="#example.more">Other network layouts</A></LI>
+<UL>
+<LI><A HREF="#internet.subnet">The Internet as a big subnet</A></LI>
+<LI><A HREF="#wireless.config">Wireless</A></LI>
+</UL>
+</UL>
+<LI><A HREF="#choose">Choosing connection types</A></LI>
+<UL>
+<LI><A HREF="#man-auto">Manual vs. automatic keying</A></LI>
+<LI><A HREF="#auto-auth">Authentication methods for auto-keying</A></LI>
+<LI><A HREF="#adv-pk">Advantages of public key methods</A></LI>
+</UL>
+<LI><A HREF="#prodsecrets">Using shared secrets in production</A></LI>
+<UL>
+<LI><A HREF="#secrets">Putting secrets in ipsec.secrets(5)</A></LI>
+<LI><A HREF="#securing.secrets">File security</A></LI>
+<LI><A HREF="#notroadshared">Shared secrets for road warriors</A></LI>
+</UL>
+<LI><A HREF="#prodman">Using manual keying in production</A></LI>
+<UL>
+<LI><A HREF="#ranbits">Creating keys with ranbits</A></LI>
+</UL>
+<LI><A HREF="#boot">Setting up connections at boot time</A></LI>
+<LI><A HREF="#multitunnel">Multiple tunnels between the same two
+ gateways</A></LI>
+<UL>
+<LI><A HREF="#advroute">One tunnel plus advanced routing</A></LI>
+</UL>
+<LI><A HREF="#opp.gate">An Opportunistic Gateway</A></LI>
+<UL>
+<LI><A HREF="#14_7_1">Start from full opportunism</A></LI>
+<LI><A HREF="#14_7_2">Reverse DNS TXT records for each protected machine</A>
+</LI>
+<LI><A HREF="#14_7_3">Publish your records</A></LI>
+<LI><A HREF="#14_7_4">...and test them</A></LI>
+<LI><A HREF="#14_7_5">No Configuration Needed</A></LI>
+</UL>
+<LI><A HREF="#extruded.config">Extruded Subnets</A></LI>
+<LI><A HREF="#roadvirt">Road Warrior with virtual IP address</A></LI>
+<LI><A HREF="#dynamic">Dynamic Network Interfaces</A></LI>
+<UL>
+<LI><A HREF="#basicdyn">Basics</A></LI>
+<LI><A HREF="#bootdyn">Boot Time</A></LI>
+<LI><A HREF="#changedyn">Change Time</A></LI>
+</UL>
+<LI><A HREF="#unencrypted">Unencrypted tunnels</A></LI>
+</UL>
+<B><A HREF="#install">Installing FreeS/WAN</A></B>
+<UL>
+<LI><A HREF="#15_1">Requirements</A></LI>
+<LI><A HREF="#15_2">Choose your install method</A></LI>
+<LI><A HREF="#15_3">FreeS/WAN ships with some Linuxes</A></LI>
+<UL>
+<LI><A HREF="#15_3_1">FreeS/WAN may be altered...</A></LI>
+<LI><A HREF="#15_3_2">You might need to create an authentication keypair</A>
+</LI>
+<LI><A HREF="#15_3_3">Start and test FreeS/WAN</A></LI>
+</UL>
+<LI><A HREF="#15_4">RPM install</A></LI>
+<UL>
+<LI><A HREF="#15_4_1">Download RPMs</A></LI>
+<LI><A HREF="#15_4_2">For freeswan.org RPMs: check signatures</A></LI>
+<LI><A HREF="#15_4_3">Install the RPMs</A></LI>
+<LI><A HREF="#15_4_4">Start and Test FreeS/WAN</A></LI>
+</UL>
+<LI><A HREF="#15_5">Install from Source</A></LI>
+<UL>
+<LI><A HREF="#15_5_1">Decide what functionality you need</A></LI>
+<LI><A HREF="#15_5_2">Download FreeS/WAN</A></LI>
+<LI><A HREF="#15_5_3">For freeswan.org source: check its signature</A></LI>
+<LI><A HREF="#15_5_4">Untar, unzip</A></LI>
+<LI><A HREF="#15_5_5">Patch if desired</A></LI>
+<LI><A HREF="#15_5_6">... and Make</A></LI>
+<UL>
+<LI><A HREF="#15_5_6_1">Userland-only Install for 2.6 kernels</A></LI>
+<LI><A HREF="#15_5_6_2">KLIPS install for 2.2, 2.4, or 2.6 kernels</A></LI>
+</UL>
+</UL>
+<LI><A HREF="#15_6">Start FreeS/WAN and test your install</A></LI>
+<LI><A HREF="#15_7">Test your install</A></LI>
+<LI><A HREF="#15_8">Making FreeS/WAN play well with others</A></LI>
+<LI><A HREF="#15_9">Configure for your needs</A></LI>
+</UL>
+<B><A HREF="#config">How to configure FreeS/WAN</A></B>
+<UL>
+<LI><A HREF="#16_1">Requirements</A></LI>
+<LI><A HREF="#config.netnet">Net-to-Net connection</A></LI>
+<UL>
+<LI><A HREF="#netnet.info.ex">Gather information</A></LI>
+<UL>
+<LI><A HREF="#16_2_1_1">Get your leftrsasigkey</A></LI>
+<LI><A HREF="#16_2_1_2">...and your rightrsasigkey</A></LI>
+</UL>
+<LI><A HREF="#16_2_2">Edit /etc/ipsec.conf</A></LI>
+<LI><A HREF="#16_2_3">Start your connection</A></LI>
+<LI><A HREF="#16_2_4">Do not MASQ or NAT packets to be tunneled</A></LI>
+<LI><A HREF="#16_2_5">Test your connection</A></LI>
+<LI><A HREF="#16_2_6">Finishing touches</A></LI>
+</UL>
+<LI><A HREF="#config.rw">Road Warrior Configuration</A></LI>
+<UL>
+<LI><A HREF="#rw.info.ex">Gather information</A></LI>
+<UL>
+<LI><A HREF="#16_3_1_1">Get your leftrsasigkey...</A></LI>
+<LI><A HREF="#16_3_1_2">...and your rightrsasigkey</A></LI>
+</UL>
+<LI><A HREF="#16_3_2">Customize /etc/ipsec.conf</A></LI>
+<LI><A HREF="#16_3_3">Start your connection</A></LI>
+<LI><A HREF="#16_3_4">Do not MASQ or NAT packets to be tunneled</A></LI>
+<LI><A HREF="#16_3_5">Test your connection</A></LI>
+<LI><A HREF="#16_3_6">Finishing touches</A></LI>
+<LI><A HREF="#16_3_7">Multiple Road Warriors</A></LI>
+</UL>
+<LI><A HREF="#16_4">What next?</A></LI>
+</UL>
+<B><A HREF="#background">Linux FreeS/WAN background</A></B>
+<UL>
+<LI><A HREF="#dns.background">Some DNS background</A></LI>
+<UL>
+<LI><A HREF="#forward.reverse">Forward and reverse maps</A></LI>
+<LI><A HREF="#17_1_2">Hierarchy and delegation</A></LI>
+<LI><A HREF="#17_1_3">Syntax of DNS records</A></LI>
+<LI><A HREF="#17_1_4">Cacheing, TTL and propagation delay</A></LI>
+</UL>
+<LI><A HREF="#MTU.trouble">Problems with packet fragmentation</A></LI>
+<LI><A HREF="#nat.background">Network address translation (NAT)</A></LI>
+<UL>
+<LI><A HREF="#17_3_1">NAT to non-routable addresses</A></LI>
+<LI><A HREF="#17_3_2">NAT to routable addresses</A></LI>
+</UL>
+</UL>
+<B><A HREF="#user.examples">FreeS/WAN script examples</A></B>
+<UL>
+<LI><A HREF="#poltorak">Poltorak's Firewall script</A></LI>
+</UL>
+<B><A HREF="#makecheck">How to configure to use &quot;make check&quot;</A></B>
+<UL>
+<LI><A HREF="#19_1">What is &quot;make check&quot;</A></LI>
+<LI><A HREF="#19_2">Running &quot;make check&quot;</A></LI>
+</UL>
+<B><A HREF="#20">How to write a &quot;make check&quot; test</A></B>
+<UL>
+<LI><A HREF="#20_1">Structure of a test</A></LI>
+<LI><A HREF="#20_2">The TESTLIST</A></LI>
+<LI><A HREF="#20_3">Test kinds</A></LI>
+<LI><A HREF="#20_4">Common parameters</A></LI>
+<LI><A HREF="#20_5">KLIPStest paramaters</A></LI>
+<LI><A HREF="#20_6">mkinsttest paramaters</A></LI>
+<LI><A HREF="#20_7">rpm_build_install_test paramaters</A></LI>
+<LI><A HREF="#20_8">libtest paramaters</A></LI>
+<LI><A HREF="#20_9">umlplutotest paramaters</A></LI>
+<LI><A HREF="#20_10">umlXhost parameters</A></LI>
+<LI><A HREF="#20_11">kernel_patch_test paramaters</A></LI>
+<LI><A HREF="#20_12">module_compile paramaters</A></LI>
+</UL>
+<B><A HREF="#21">Current pitfalls</A></B>
+<BR>
+<BR><B><A HREF="#umltesting">User-Mode-Linux Testing guide</A></B>
+<UL>
+<LI><A HREF="#22_1">Preliminary Notes on BIND</A></LI>
+<LI><A HREF="#22_2">Steps to Install UML for FreeS/WAN</A></LI>
+</UL>
+<B><A HREF="#23">Debugging the kernel with GDB</A></B>
+<UL>
+<LI><A HREF="#23_1">Other notes about debugging</A></LI>
+</UL>
+<B><A HREF="#24">User-Mode-Linux mysteries</A></B>
+<BR>
+<BR><B><A HREF="#25">Getting more info from uml_netjig</A></B>
+<BR>
+<BR><B><A HREF="#politics">History and politics of cryptography</A></B>
+<UL>
+<LI><A HREF="#intro.politics">Introduction</A></LI>
+<UL>
+<LI><A HREF="#26_1_1">History</A></LI>
+<UL>
+<LI><A HREF="#26_1_1_1">World War II</A></LI>
+<LI><A HREF="#postwar">Postwar and Cold War</A></LI>
+<LI><A HREF="#recent">Recent history -- the crypto wars</A></LI>
+</UL>
+<LI><A HREF="#intro.poli">Politics</A></LI>
+<LI><A HREF="#26_1_3">Links</A></LI>
+<LI><A HREF="#26_1_4">Outline of this section</A></LI>
+</UL>
+<LI><A HREF="#leader">From our project leader</A></LI>
+<UL>
+<LI><A HREF="#gilmore">Swan: Securing the Internet against Wiretapping</A>
+</LI>
+<UL>
+<LI><A HREF="#26_2_1_1">Deployment of IPSEC</A></LI>
+<LI><A HREF="#26_2_1_2">Current status</A></LI>
+<LI><A HREF="#26_2_1_3">Why?</A></LI>
+<LI><A HREF="#26_2_1_4">What You Can Do</A></LI>
+<LI><A HREF="#26_2_1_5">Related projects</A></LI>
+</UL>
+<LI><A HREF="#policestate">Stopping wholesale monitoring</A></LI>
+</UL>
+<LI><A HREF="#weak">Government promotion of weak crypto</A></LI>
+<UL>
+<LI><A HREF="#escrow">Escrowed encryption</A></LI>
+<LI><A HREF="#shortkeys">Limited key lengths</A></LI>
+<UL>
+<LI><A HREF="#26_3_2_1">Some real trade-offs</A></LI>
+</UL>
+</UL>
+<LI><A HREF="#exlaw">Cryptography Export Laws</A></LI>
+<UL>
+<LI><A HREF="#USlaw">US Law</A></LI>
+<UL>
+<LI><A HREF="#UScontrib">US contributions to FreeS/WAN</A></LI>
+</UL>
+<LI><A HREF="#wrong">What's wrong with restrictions on cryptography</A></LI>
+<LI><A HREF="#Wassenaar">The Wassenaar Arrangement</A></LI>
+<LI><A HREF="#status">Export status of Linux FreeS/WAN</A></LI>
+<LI><A HREF="#help">Help spread IPsec around</A></LI>
+</UL>
+<LI><A HREF="#desnotsecure">DES is Not Secure</A></LI>
+<UL>
+<LI><A HREF="#deshware">Dedicated hardware breaks DES in a few days</A></LI>
+<LI><A HREF="#spooks">Spooks may break DES faster yet</A></LI>
+<LI><A HREF="#desnet">Networks break DES in a few weeks</A></LI>
+<LI><A HREF="#no_des">We disable DES</A></LI>
+<LI><A HREF="#40joke">40-bits is laughably weak</A></LI>
+<LI><A HREF="#altdes">Triple DES is almost certainly secure</A></LI>
+<LI><A HREF="#aes.ipsec">AES in IPsec</A></LI>
+</UL>
+<LI><A HREF="#press">Press coverage of Linux FreeS/WAN:</A></LI>
+<UL>
+<LI><A HREF="#26_6_1">FreeS/WAN 1.0 press</A></LI>
+<LI><A HREF="#release">Press release for version 1.0</A></LI>
+</UL>
+</UL>
+<B><A HREF="#ipsec.detail">The IPsec protocols</A></B>
+<UL>
+<LI><A HREF="#27_1">Protocols and phases</A></LI>
+<LI><A HREF="#others">Applying IPsec</A></LI>
+<UL>
+<LI><A HREF="#advantages">Advantages of IPsec</A></LI>
+<LI><A HREF="#limitations">Limitations of IPsec</A></LI>
+<LI><A HREF="#uses">IPsec is a general mechanism for securing IP</A></LI>
+<LI><A HREF="#authonly">Using authentication without encryption</A></LI>
+<LI><A HREF="#encnoauth">Encryption without authentication is dangerous</A>
+</LI>
+<LI><A HREF="#multilayer">Multiple layers of IPsec processing are
+ possible</A></LI>
+<LI><A HREF="#traffic.resist">Resisting traffic analysis</A></LI>
+<UL>
+<LI><A HREF="#extra">Using &quot;unnecessary&quot; encryption</A></LI>
+<LI><A HREF="#multi-encrypt">Using multiple encryption</A></LI>
+<LI><A HREF="#fewer">Using fewer tunnels</A></LI>
+</UL>
+</UL>
+<LI><A HREF="#primitives">Cryptographic components</A></LI>
+<UL>
+<LI><A HREF="#block.cipher">Block ciphers</A></LI>
+<LI><A HREF="#hash.ipsec">Hash functions</A></LI>
+<UL>
+<LI><A HREF="#hmac.ipsec">The HMAC construct</A></LI>
+<LI><A HREF="#27_3_2_2">Choice of hash algorithm</A></LI>
+</UL>
+<LI><A HREF="#DH.keying">Diffie-Hellman key agreement</A></LI>
+<LI><A HREF="#RSA.auth">RSA authentication</A></LI>
+</UL>
+<LI><A HREF="#structure">Structure of IPsec</A></LI>
+<UL>
+<LI><A HREF="#IKE.ipsec">IKE (Internet Key Exchange)</A></LI>
+<UL>
+<LI><A HREF="#phases">Phases of IKE</A></LI>
+<LI><A HREF="#sequence">Sequence of messages in IKE</A></LI>
+<LI><A HREF="#struct.exchange">Structure of IKE messages</A></LI>
+</UL>
+<LI><A HREF="#services">IPsec Services, AH and ESP</A></LI>
+<LI><A HREF="#AH.ipsec">The Authentication Header (AH)</A></LI>
+<UL>
+<LI><A HREF="#keyed">Keyed MD5 and Keyed SHA</A></LI>
+<LI><A HREF="#sequence">Sequence numbers</A></LI>
+</UL>
+<LI><A HREF="#ESP.ipsec">Encapsulated Security Payload (ESP)</A></LI>
+</UL>
+<LI><A HREF="#modes">IPsec modes</A></LI>
+<UL>
+<LI><A HREF="#tunnel.ipsec">Tunnel mode</A></LI>
+<LI><A HREF="#transport.ipsec">Transport mode</A></LI>
+</UL>
+<LI><A HREF="#parts">FreeS/WAN parts</A></LI>
+<UL>
+<LI><A HREF="#KLIPS.ipsec">KLIPS: Kernel IPsec Support</A></LI>
+<LI><A HREF="#Pluto.ipsec">The Pluto daemon</A></LI>
+<LI><A HREF="#command">The ipsec(8) command</A></LI>
+<LI><A HREF="#ipsec.conf">Linux FreeS/WAN configuration file</A></LI>
+</UL>
+<LI><A HREF="#key">Key management</A></LI>
+<UL>
+<LI><A HREF="#current">Currently Implemented Methods</A></LI>
+<UL>
+<LI><A HREF="#manual">Manual keying</A></LI>
+<LI><A HREF="#auto">Automatic keying</A></LI>
+</UL>
+<LI><A HREF="#notyet">Methods not yet implemented</A></LI>
+<UL>
+<LI><A HREF="#noauth">Unauthenticated key exchange</A></LI>
+<LI><A HREF="#DNS">Key exchange using DNS</A></LI>
+<LI><A HREF="#PKI">Key exchange using a PKI</A></LI>
+<LI><A HREF="#photuris">Photuris</A></LI>
+<LI><A HREF="#skip">SKIP</A></LI>
+</UL>
+</UL>
+</UL>
+<B><A HREF="#lists">Mailing lists and newsgroups</A></B>
+<UL>
+<LI><A HREF="#list.fs">Mailing lists about FreeS/WAN</A></LI>
+<UL>
+<LI><A HREF="#projlist">The project mailing lists</A></LI>
+<UL>
+<LI><A HREF="#which.list">Which list should I use?</A></LI>
+<LI><A HREF="#policy.list">List policies</A></LI>
+</UL>
+<LI><A HREF="#archive">Archives of the lists</A></LI>
+</UL>
+<LI><A HREF="#indexes">Indexes of mailing lists</A></LI>
+<LI><A HREF="#otherlists">Lists for related software and topics</A></LI>
+<UL>
+<LI><A HREF="#28_3_1">Products that include FreeS/WAN</A></LI>
+<LI><A HREF="#linux.lists">Linux mailing lists</A></LI>
+<LI><A HREF="#ietf">Lists for IETF working groups</A></LI>
+<LI><A HREF="#other">Other mailing lists</A></LI>
+</UL>
+<LI><A HREF="#newsgroups">Usenet newsgroups</A></LI>
+</UL>
+<B><A HREF="#weblink">Web links</A></B>
+<UL>
+<LI><A HREF="#freeswan">The Linux FreeS/WAN Project</A></LI>
+<UL>
+<LI><A HREF="#patch">Add-ons and patches for FreeS/WAN</A></LI>
+<UL>
+<LI><A HREF="#29_1_1_1">Current patches</A></LI>
+<LI><A HREF="#29_1_1_2">Older patches</A></LI>
+<LI><A HREF="#VPN.masq">VPN masquerade patches</A></LI>
+</UL>
+<LI><A HREF="#dist">Distributions including FreeS/WAN</A></LI>
+<LI><A HREF="#used">Things FreeS/WAN uses or could use</A></LI>
+<LI><A HREF="#alternatives">Other approaches to VPNs for Linux</A></LI>
+</UL>
+<LI><A HREF="#ipsec.link">The IPsec Protocols</A></LI>
+<UL>
+<LI><A HREF="#general">General IPsec or VPN information</A></LI>
+<LI><A HREF="#overview">IPsec overview documents or slide sets</A></LI>
+<LI><A HREF="#otherlang">IPsec information in languages other than
+ English</A></LI>
+<LI><A HREF="#RFCs1">RFCs and other reference documents</A></LI>
+<LI><A HREF="#analysis">Analysis and critiques of IPsec protocols</A></LI>
+<LI><A HREF="#IP.background">Background information on IP</A></LI>
+</UL>
+<LI><A HREF="#implement">IPsec Implementations</A></LI>
+<UL>
+<LI><A HREF="#linuxprod">Linux products</A></LI>
+<LI><A HREF="#router">IPsec in router products</A></LI>
+<LI><A HREF="#fw.web">IPsec in firewall products</A></LI>
+<LI><A HREF="#ipsecos">Operating systems with IPsec support</A></LI>
+<LI><A HREF="#29_3_5">IPsec on network cards</A></LI>
+<LI><A HREF="#opensource">Open source IPsec implementations</A></LI>
+<UL>
+<LI><A HREF="#linuxipsec">Other Linux IPsec implementations</A></LI>
+<LI><A HREF="#BSD">IPsec for BSD Unix</A></LI>
+<LI><A HREF="#misc">IPsec for other systems</A></LI>
+</UL>
+<LI><A HREF="#interop.web">Interoperability</A></LI>
+<UL>
+<LI><A HREF="#result">Interoperability results</A></LI>
+<LI><A HREF="#test1">Interoperability test sites</A></LI>
+</UL>
+</UL>
+<LI><A HREF="#linux.link">Linux links</A></LI>
+<UL>
+<LI><A HREF="#linux.basic">Basic and tutorial Linux information</A></LI>
+<LI><A HREF="#general">General Linux sites</A></LI>
+<LI><A HREF="#docs.ldp">Documentation</A></LI>
+<LI><A HREF="#advroute.web">Advanced routing</A></LI>
+<LI><A HREF="#linsec">Security for Linux</A></LI>
+<LI><A HREF="#firewall.linux">Linux firewalls</A></LI>
+<LI><A HREF="#linux.misc">Miscellaneous Linux information</A></LI>
+</UL>
+<LI><A HREF="#crypto.link">Crypto and security links</A></LI>
+<UL>
+<LI><A HREF="#security">Crypto and security resources</A></LI>
+<UL>
+<LI><A HREF="#std.links">The standard link collections</A></LI>
+<LI><A HREF="#FAQ">Frequently Asked Question (FAQ) documents</A></LI>
+<LI><A HREF="#cryptover">Tutorials</A></LI>
+<LI><A HREF="#standards">Crypto and security standards</A></LI>
+<LI><A HREF="#quotes">Crypto quotes</A></LI>
+</UL>
+<LI><A HREF="#policy">Cryptography law and policy</A></LI>
+<UL>
+<LI><A HREF="#legal">Surveys of crypto law</A></LI>
+<LI><A HREF="#oppose">Organisations opposing crypto restrictions</A></LI>
+<LI><A HREF="#other.policy">Other information on crypto policy</A></LI>
+</UL>
+<LI><A HREF="#crypto.tech">Cryptography technical information</A></LI>
+<UL>
+<LI><A HREF="#cryptolinks">Collections of crypto links</A></LI>
+<LI><A HREF="#papers">Lists of online cryptography papers</A></LI>
+<LI><A HREF="#interesting">Particularly interesting papers</A></LI>
+</UL>
+<LI><A HREF="#compsec">Computer and network security</A></LI>
+<UL>
+<LI><A HREF="#seclink">Security links</A></LI>
+<LI><A HREF="#firewall.web">Firewall links</A></LI>
+<LI><A HREF="#vpn">VPN links</A></LI>
+<LI><A HREF="#tools">Security tools</A></LI>
+</UL>
+<LI><A HREF="#people">Links to home pages</A></LI>
+</UL>
+</UL>
+<B><A HREF="#ourgloss">Glossary for the Linux FreeS/WAN project</A></B>
+<UL>
+<LI><A HREF="#jump">Jump to a letter in the glossary</A></LI>
+<LI><A HREF="#gloss">Other glossaries</A></LI>
+<LI><A HREF="#definitions">Definitions</A></LI>
+</UL>
+<B><A HREF="#biblio">Bibliography for the Linux FreeS/WAN project</A></B>
+<BR>
+<BR><B><A HREF="#RFC">IPsec RFCs and related documents</A></B>
+<UL>
+<LI><A HREF="#RFCfile">The RFCs.tar.gz Distribution File</A></LI>
+<LI><A HREF="#sources">Other sources for RFCs &amp; Internet drafts</A></LI>
+<UL>
+<LI><A HREF="#RFCdown">RFCs</A></LI>
+<LI><A HREF="#drafts">Internet Drafts</A></LI>
+<LI><A HREF="#FIPS1">FIPS standards</A></LI>
+</UL>
+<LI><A HREF="#RFCs.tar.gz">What's in the RFCs.tar.gz bundle?</A></LI>
+<UL>
+<LI><A HREF="#rfc.ov">Overview RFCs</A></LI>
+<LI><A HREF="#basic.prot">Basic protocols</A></LI>
+<LI><A HREF="#key.ike">Key management</A></LI>
+<LI><A HREF="#rfc.detail">Details of various things used</A></LI>
+<LI><A HREF="#rfc.ref">Older RFCs which may be referenced</A></LI>
+<LI><A HREF="#rfc.dns">RFCs for secure DNS service, which IPsec may use</A>
+</LI>
+<LI><A HREF="#rfc.exp">RFCs labelled &quot;experimental&quot;</A></LI>
+<LI><A HREF="#rfc.rel">Related RFCs</A></LI>
+</UL>
+</UL>
+<B><A HREF="#roadmap">Distribution Roadmap: What's Where in Linux
+ FreeS/WAN</A></B>
+<UL>
+<LI><A HREF="#top">Top directory</A></LI>
+<LI><A HREF="#doc">Documentation</A></LI>
+<LI><A HREF="#klips.roadmap">KLIPS: kernel IP security</A></LI>
+<LI><A HREF="#pluto.roadmap">Pluto key and connection management daemon</A>
+</LI>
+<LI><A HREF="#utils">Utils</A></LI>
+<LI><A HREF="#lib">Libraries</A></LI>
+<UL>
+<LI><A HREF="#fswanlib">FreeS/WAN Library</A></LI>
+<LI><A HREF="#otherlib">Imported Libraries</A></LI>
+<UL>
+<LI><A HREF="#33_6_2_1">LibDES</A></LI>
+<LI><A HREF="#33_6_2_2">GMP</A></LI>
+</UL>
+</UL>
+</UL>
+<B><A HREF="#umltesting">User-Mode-Linux Testing guide</A></B>
+<UL>
+<LI><A HREF="#34_1">Preliminary Notes on BIND</A></LI>
+<LI><A HREF="#34_2">Steps to Install UML for FreeS/WAN</A></LI>
+</UL>
+<B><A HREF="#35">Debugging the kernel with GDB</A></B>
+<UL>
+<LI><A HREF="#35_1">Other notes about debugging</A></LI>
+</UL>
+<B><A HREF="#36">User-Mode-Linux mysteries</A></B>
+<BR>
+<BR><B><A HREF="#37">Getting more info from uml_netjig</A></B>
+<BR>
+<BR><B><A HREF="#makecheck">How to configure to use &quot;make check&quot;</A></B>
+<UL>
+<LI><A HREF="#38_1">What is &quot;make check&quot;</A></LI>
+<LI><A HREF="#38_2">Running &quot;make check&quot;</A></LI>
+</UL>
+<B><A HREF="#39">How to write a &quot;make check&quot; test</A></B>
+<UL>
+<LI><A HREF="#39_1">Structure of a test</A></LI>
+<LI><A HREF="#39_2">The TESTLIST</A></LI>
+<LI><A HREF="#39_3">Test kinds</A></LI>
+<LI><A HREF="#39_4">Common parameters</A></LI>
+<LI><A HREF="#39_5">KLIPStest paramaters</A></LI>
+<LI><A HREF="#39_6">mkinsttest paramaters</A></LI>
+<LI><A HREF="#39_7">rpm_build_install_test paramaters</A></LI>
+<LI><A HREF="#39_8">libtest paramaters</A></LI>
+<LI><A HREF="#39_9">umlplutotest paramaters</A></LI>
+<LI><A HREF="#39_10">umlXhost parameters</A></LI>
+<LI><A HREF="#39_11">kernel_patch_test paramaters</A></LI>
+<LI><A HREF="#39_12">module_compile paramaters</A></LI>
+</UL>
+<B><A HREF="#40">Current pitfalls</A></B>
+<BR>
+<BR><B><A HREF="#nightly">Nightly regression testing</A></B>
+<BR>
+<BR><B><A HREF="#nightlyhowto">How to setup the nightly build</A></B>
+<UL>
+<LI><A HREF="#42_1"> Files you need to know about</A></LI>
+<LI><A HREF="#42_2">Configuring freeswan-regress-env.sh</A></LI>
+</UL>
+<HR>
+<H1><A name="intro">Introduction</A></H1>
+<P>This section gives an overview of:</P>
+<UL>
+<LI>what IP Security (IPsec) does</LI>
+<LI>how IPsec works</LI>
+<LI>why we are implementing it for Linux</LI>
+<LI>how this implementation works</LI>
+</UL>
+<P>This section is intended to cover only the essentials,<EM> things you
+ should know before trying to use FreeS/WAN.</EM></P>
+<P>For more detailed background information, see the<A href="#politics">
+ history and politics</A> and<A href="#ipsec.detail"> IPsec protocols</A>
+ sections.</P>
+<H2><A name="ipsec.intro">IPsec, Security for the Internet Protocol</A></H2>
+<P>FreeS/WAN is a Linux implementation of the IPsec (IP security)
+ protocols. IPsec provides<A href="#encryption"> encryption</A> and<A href="#authentication">
+ authentication</A> services at the IP (Internet Protocol) level of the
+ network protocol stack.</P>
+<P>Working at this level, IPsec can protect any traffic carried over IP,
+ unlike other encryption which generally protects only a particular
+ higher-level protocol --<A href="#PGP"> PGP</A> for mail,<A href="#ssh">
+ SSH</A> for remote login,<A href="#SSL"> SSL</A> for web work, and so
+ on. This approach has both considerable advantages and some
+ limitations. For discussion, see our<A href="#others"> IPsec section</A>
+</P>
+<P>IPsec can be used on any machine which does IP networking. Dedicated
+ IPsec gateway machines can be installed wherever required to protect
+ traffic. IPsec can also run on routers, on firewall machines, on
+ various application servers, and on end-user desktop or laptop
+ machines.</P>
+<P>Three protocols are used</P>
+<UL>
+<LI><A href="#AH">AH</A> (Authentication Header) provides a packet-level
+ authentication service</LI>
+<LI><A href="#ESP">ESP</A> (Encapsulating Security Payload) provides
+ encryption plus authentication</LI>
+<LI><A href="#IKE">IKE</A> (Internet Key Exchange) negotiates connection
+ parameters, including keys, for the other two</LI>
+</UL>
+<P>Our implementation has three main parts:</P>
+<UL>
+<LI><A href="#KLIPS">KLIPS</A> (kernel IPsec) implements AH, ESP, and
+ packet handling within the kernel</LI>
+<LI><A href="#Pluto">Pluto</A> (an IKE daemon) implements IKE,
+ negotiating connections with other systems</LI>
+<LI>various scripts provide an adminstrator's interface to the machinery</LI>
+</UL>
+<P>IPsec is optional for the current (version 4) Internet Protocol.
+ FreeS/WAN adds IPsec to the Linux IPv4 network stack. Implementations
+ of<A href="#ipv6.gloss"> IP version 6</A> are required to include
+ IPsec. Work toward integrating FreeS/WAN into the Linux IPv6 stack has<A
+href="#ipv6"> started</A>.</P>
+<P>For more information on IPsec, see our<A href="#ipsec.detail"> IPsec
+ protocols</A> section, our collection of<A href="#ipsec.link"> IPsec
+ links</A> or the<A href="#RFC"> RFCs</A> which are the official
+ definitions of these protocols.</P>
+<H3><A name="intro.interop">Interoperating with other IPsec
+ implementations</A></H3>
+<P>IPsec is designed to let different implementations work together. We
+ provide:</P>
+<UL>
+<LI>a<A href="#implement"> list</A> of some other implementations</LI>
+<LI>information on<A href="#interop"> using FreeS/WAN with other
+ implementations</A></LI>
+</UL>
+<P>The VPN Consortium fosters cooperation among implementers and
+ interoperability among implementations. Their<A href="http://www.vpnc.org/">
+ web site</A> has much more information.</P>
+<H3><A name="advantages">Advantages of IPsec</A></H3>
+<P>IPsec has a number of security advantages. Here are some
+ independently written articles which discuss these:</P>
+<P><A HREF="http://www.sans.org/rr/"> SANS institute papers</A>. See the
+ section on Encryption &amp;VPNs.
+<BR><A HREF="http://www.cisco.com/en/US/netsol/ns110/ns170/ns171/ns128/networking_solutions_white_papers_list.html">
+ Cisco's white papers on &quot;Networking Solutions&quot;</A>.
+<BR><A HREF="http://iscs.sourceforge.net/HowWhyBrief/HowWhyBrief.html">
+ Advantages of ISCS (Linux Integrated Secure Communications System;
+ includes FreeS/WAN and other software)</A>.</P>
+<H3><A name="applications">Applications of IPsec</A></H3>
+<P>Because IPsec operates at the network layer, it is remarkably
+ flexible and can be used to secure nearly any type of Internet traffic.
+ Two applications, however, are extremely widespread:</P>
+<UL>
+<LI>a<A href="#VPN"> Virtual Private Network</A>, or VPN, allows
+ multiple sites to communicate securely over an insecure Internet by
+ encrypting all communication between the sites.</LI>
+<LI>&quot;Road Warriors&quot; connect to the office from home, or perhaps from a
+ hotel somewhere</LI>
+</UL>
+<P>There is enough opportunity in these applications that vendors are
+ flocking to them. IPsec is being built into routers, into firewall
+ products, and into major operating systems, primarily to support these
+ applications. See our<A href="#implement"> list</A> of implementations
+ for details.</P>
+<P>We support both of those applications, and various less common IPsec
+ applications as well, but we also add one of our own:</P>
+<UL>
+<LI>opportunistic encryption, the ability to set up FreeS/WAN gateways
+ so that any two of them can encrypt to each other, and will do so
+ whenever packets pass between them.</LI>
+</UL>
+<P>This is an extension we are adding to the protocols. FreeS/WAN is the
+ first prototype implementation, though we hope other IPsec
+ implementations will adopt the technique once we demonstrate it. See<A href="#goals">
+ project goals</A> below for why we think this is important.</P>
+<P>A somewhat more detailed description of each of these applications is
+ below. Our<A href="#quick_guide"> quickstart</A> section will show you
+ how to build each of them.</P>
+<H4><A name="makeVPN">Using secure tunnels to create a VPN</A></H4>
+<P>A VPN, or<STRONG> V</STRONG>irtual<STRONG> P</STRONG>rivate<STRONG> N</STRONG>
+etwork lets two networks communicate securely when the only connection
+ between them is over a third network which they do not trust.</P>
+<P>The method is to put a security gateway machine between each of the
+ communicating networks and the untrusted network. The gateway machines
+ encrypt packets entering the untrusted net and decrypt packets leaving
+ it, creating a secure tunnel through it.</P>
+<P>If the cryptography is strong, the implementation is careful, and the
+ administration of the gateways is competent, then one can reasonably
+ trust the security of the tunnel. The two networks then behave like a
+ single large private network, some of whose links are encrypted tunnels
+ through untrusted nets.</P>
+<P>Actual VPNs are often more complex. One organisation may have fifty
+ branch offices, plus some suppliers and clients, with whom it needs to
+ communicate securely. Another might have 5,000 stores, or 50,000
+ point-of-sale devices. The untrusted network need not be the Internet.
+ All the same issues arise on a corporate or institutional network
+ whenever two departments want to communicate privately with each other.</P>
+<P>Administratively, the nice thing about many VPN setups is that large
+ parts of them are static. You know the IP addresses of most of the
+ machines involved. More important, you know they will not change on
+ you. This simplifies some of the admin work. For cases where the
+ addresses do change, see the next section.</P>
+<H4><A name="road.intro">Road Warriors</A></H4>
+<P>The prototypical &quot;Road Warrior&quot; is a traveller connecting to home
+ base from a laptop machine. Administratively, most of the same problems
+ arise for a telecommuter connecting from home to the office, especially
+ if the telecommuter does not have a static IP address.</P>
+<P>For purposes of this document:</P>
+<UL>
+<LI>anyone with a dynamic IP address is a &quot;Road Warrior&quot;.</LI>
+<LI>any machine doing IPsec processing is a &quot;gateway&quot;. Think of the
+ single-user road warrior machine as a gateway with a degenerate subnet
+ (one machine, itself) behind it.</LI>
+</UL>
+<P>These require somewhat different setup than VPN gateways with static
+ addresses and with client systems behind them, but are basically not
+ problematic.</P>
+<P>There are some difficulties which appear for some road warrior
+ connections:</P>
+<UL>
+<LI>Road Wariors who get their addresses via DHCP may have a problem.
+ FreeS/WAN can quite happily build and use a tunnel to such an address,
+ but when the DHCP lease expires, FreeS/WAN does not know that. The
+ tunnel fails, and the only recovery method is to tear it down and
+ re-build it.</LI>
+<LI>If<A href="#NAT.gloss"> Network Address Translation</A> (NAT) is
+ applied between the two IPsec Gateways, this breaks IPsec. IPsec
+ authenticates packets on an end-to-end basis, to ensure they are not
+ altered en route. NAT rewrites packets as they go by. See our<A href="#NAT">
+ firewalls</A> document for details.</LI>
+</UL>
+<P>In most situations, however, FreeS/WAN supports road warrior
+ connections just fine.</P>
+<H4><A name="opp.intro">Opportunistic encryption</A></H4>
+<P>One of the reasons we are working on FreeS/WAN is that it gives us
+ the opportunity to add what we call opportuntistic encryption. This
+ means that any two FreeS/WAN gateways will be able to encrypt their
+ traffic, even if the two gateway administrators have had no prior
+ contact and neither system has any preset information about the other.</P>
+<P>Both systems pick up the authentication information they need from
+ the<A href="#DNS"> DNS</A> (domain name service), the service they
+ already use to look up IP addresses. Of course the administrators must
+ put that information in the DNS, and must set up their gateways with
+ opportunistic encryption enabled. Once that is done, everything is
+ automatic. The gateways look for opportunities to encrypt, and encrypt
+ whatever they can. Whether they also accept unencrypted communication
+ is a policy decision the administrator can make.</P>
+<P>This technique can give two large payoffs:</P>
+<UL>
+<LI>It reduces the administrative overhead for IPsec enormously. You
+ configure your gateway and thereafter everything is automatic. The need
+ to configure the system on a per-tunnel basis disappears. Of course,
+ FreeS/WAN allows specifically configured tunnels to co-exist with
+ opportunistic encryption, but we hope to make them unnecessary in most
+ cases.</LI>
+<LI>It moves us toward a more secure Internet, allowing users to create
+ an environment where message privacy is the default. All messages can
+ be encrypted, provided the other end is willing to co-operate. See our<A
+href="#politics"> history and politics of cryptography</A> section for
+ discussion of why we think this is needed.</LI>
+</UL>
+<P>Opportunistic encryption is not (yet?) a standard part of the IPsec
+ protocols, but an extension we are proposing and demonstrating. For
+ details of our design, see<A href="#applied"> links</A> below.</P>
+<P>Only one current product we know of implements a form of
+ opportunistic encryption.<A href="#ssmail"> Secure sendmail</A> will
+ automatically encrypt server-to-server mail transfers whenever
+ possible.</P>
+<H3><A name="types">The need to authenticate gateways</A></H3>
+<P>A complication, which applies to any type of connection -- VPN, Road
+ Warrior or opportunistic -- is that a secure connection cannot be
+ created magically.<EM> There must be some mechanism which enables the
+ gateways to reliably identify each other.</EM> Without this, they
+ cannot sensibly trust each other and cannot create a genuinely secure
+ link.</P>
+<P>Any link they do create without some form of<A href="#authentication">
+ authentication</A> will be vulnerable to a<A href="#middle">
+ man-in-the-middle attack</A>. If<A href="#alicebob"> Alice and Bob</A>
+ are the people creating the connection, a villian who can re-route or
+ intercept the packets can pose as Alice while talking to Bob and pose
+ as Bob while talking to Alice. Alice and Bob then both talk to the man
+ in the middle, thinking they are talking to each other, and the villain
+ gets everything sent on the bogus &quot;secure&quot; connection.</P>
+<P>There are two ways to build links securely, both of which exclude the
+ man-in-the middle:</P>
+<UL>
+<LI>with<STRONG> manual keying</STRONG>, Alice and Bob share a secret
+ key (which must be transmitted securely, perhaps in a note or via PGP
+ or SSH) to encrypt their messages. For FreeS/WAN, such keys are stored
+ in the<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf(5)</A> file. Of
+ course, if an enemy gets the key, all is lost.</LI>
+<LI>with<STRONG> automatic keying</STRONG>, the two systems authenticate
+ each other and negotiate their own secret keys. The keys are
+ automatically changed periodically.</LI>
+</UL>
+<P>Automatic keying is much more secure, since if an enemy gets one key
+ only messages between the previous re-keying and the next are exposed.
+ It is therefore the usual mode of operation for most IPsec deployment,
+ and the mode we use in our setup examples. FreeS/WAN does support
+ manual keying for special circumstanes. See this<A href="#prodman">
+ section</A>.</P>
+<P>For automatic keying, the two systems must authenticate each other
+ during the negotiations. There is a choice of methods for this:</P>
+<UL>
+<LI>a<STRONG> shared secret</STRONG> provides authentication. If Alice
+ and Bob are the only ones who know a secret and Alice recives a message
+ which could not have been created without that secret, then Alice can
+ safely believe the message came from Bob.</LI>
+<LI>a<A href="#public"> public key</A> can also provide authentication.
+ If Alice receives a message signed with Bob's private key (which of
+ course only he should know) and she has a trustworthy copy of his
+ public key (so that she can verify the signature), then she can safely
+ believe the message came from Bob.</LI>
+</UL>
+<P>Public key techniques are much preferable, for reasons discussed<A href="#choose">
+ later</A>, and will be used in all our setup examples. FreeS/WAN does
+ also support auto-keying with shared secret authentication. See this<A href="#prodsecrets">
+ section</A>.</P>
+<H2><A name="project">The FreeS/WAN project</A></H2>
+<P>For complete information on the project, see our web site,<A href="http://liberty.freeswan.org">
+ freeswan.org</A>.</P>
+<P>In summary, we are implementing the<A href="#IPSEC"> IPsec</A>
+ protocols for Linux and extending them to do<A href="#carpediem">
+ opportunistic encryption</A>.</P>
+<H3><A name="goals">Project goals</A></H3>
+<P>Our overall goal in FreeS/WAN is to make the Internet more secure and
+ more private.</P>
+<P>Our IPsec implementation supports VPNs and Road Warriors of course.
+ Those are important applications. Many users will want FreeS/WAN to
+ build corporate VPNs or to provide secure remote access.</P>
+<P>However, our goals in building it go beyond that. We are trying to
+ help<STRONG> build security into the fabric of the Internet</STRONG> so
+ that anyone who choses to communicate securely can do so, as easily as
+ they can do anything else on the net.</P>
+<P>More detailed objectives are:</P>
+<UL>
+<LI>extend IPsec to do<A href="#carpediem"> opportunistic encryption</A>
+ so that
+<UL>
+<LI>any two systems can secure their communications without a
+ pre-arranged connection</LI>
+<LI><STRONG>secure connections can be the default</STRONG>, falling back
+ to unencrypted connections only if:
+<UL>
+<LI><EM>both</EM> the partner is not set up to co-operate on securing
+ the connection</LI>
+<LI><EM>and</EM> your policy allows insecure connections</LI>
+</UL>
+</LI>
+<LI>a significant fraction of all Internet traffic is encrypted</LI>
+<LI>wholesale monitoring of the net (<A href="#intro.poli">examples</A>)
+ becomes difficult or impossible</LI>
+</UL>
+</LI>
+<LI>help make IPsec widespread by providing an implementation with no
+ restrictions:
+<UL>
+<LI>freely available in source code under the<A href="#GPL"> GNU General
+ Public License</A></LI>
+<LI>running on a range of readily available hardware</LI>
+<LI>not subject to US or other nations'<A href="#exlaw"> export
+ restrictions</A>.
+<BR> Note that in order to avoid<EM> even the appearance</EM> of being
+ subject to those laws, the project cannot accept software contributions
+ --<EM> not even one-line bug fixes</EM> -- from US residents or
+ citizens.</LI>
+</UL>
+</LI>
+<LI>provide a high-quality IPsec implementation for Linux
+<UL>
+<LI>portable to all CPUs Linux supports:<A href="#CPUs"> (current list)</A>
+</LI>
+<LI>interoperable with other IPsec implementations:<A href="#interop">
+ (current list)</A></LI>
+</UL>
+</LI>
+</UL>
+<P>If we can get opportunistic encryption implemented and widely
+ deployed, then it becomes impossible for even huge well-funded agencies
+ to monitor the net.</P>
+<P>See also our section on<A href="#politics"> history and politics</A>
+ of cryptography, which includes our project leader's<A href="#gilmore">
+ rationale</A> for starting the project.</P>
+<H3><A name="staff">Project team</A></H3>
+<P>Two of the team are from the US and can therefore contribute no code:</P>
+<UL>
+<LI>John Gilmore: founder and policy-maker (<A href="http://www.toad.com/gnu/">
+home page</A>)</LI>
+<LI>Hugh Daniel: project manager, Most Demented Tester, and occasionally
+ Pointy-Haired Boss</LI>
+</UL>
+<P>The rest of the team are Canadians, working in Canada. (<A href="#status">
+Why Canada?</A>)</P>
+<UL>
+<LI>Hugh Redelmeier:<A href="#Pluto"> Pluto daemon</A> programmer</LI>
+<LI>Richard Guy Briggs:<A href="#KLIPS"> KLIPS</A> programmer</LI>
+<LI>Michael Richardson: hacker without portfolio</LI>
+<LI>Claudia Schmeing: documentation</LI>
+<LI>Sam Sgro: technical support via the<A href="#lists"> mailing lists</A>
+</LI>
+</UL>
+<P>The project is funded by civil libertarians who consider our goals
+ worthwhile. Most of the team are paid for this work.</P>
+<P>People outside this core team have made substantial contributions.
+ See</P>
+<UL>
+<LI>our<A href="../CREDITS"> CREDITS</A> file</LI>
+<LI>the<A href="#patch"> patches and add-ons</A> section of our web
+ references file</LI>
+<LI>lists below of user-written<A href="#howto"> HowTos</A> and<A href="#applied">
+ other papers</A></LI>
+</UL>
+<P>Additional contributions are welcome. See the<A href="#contrib.faq">
+ FAQ</A> for details.</P>
+<H2><A name="products">Products containing FreeS/WAN</A></H2>
+<P>Unfortunately the<A href="#exlaw"> export laws</A> of some countries
+ restrict the distribution of strong cryptography. FreeS/WAN is
+ therefore not in the standard Linux kernel and not in all CD or web
+ distributions.</P>
+<P>FreeS/WAN is, however, quite widely used. Products we know of that
+ use it are listed below. We would appreciate hearing, via the<A href="#lists">
+ mailing lists</A>, of any we don't know of.</P>
+<H3><A name="distwith">Full Linux distributions</A></H3>
+<P>FreeS/WAN is included in various general-purpose Linux distributions,
+ mostly from countries (shown in brackets) with more sensible laws:</P>
+<UL>
+<LI><A href="http://www.suse.com/">SuSE Linux</A> (Germany)</LI>
+<LI><A href="http://www.conectiva.com">Conectiva</A> (Brazil)</LI>
+<LI><A href="http://www.linux-mandrake.com/en/">Mandrake</A> (France)</LI>
+<LI><A href="http://www.debian.org">Debian</A></LI>
+<LI>the<A href="http://www.pld.org.pl/"> Polish(ed) Linux Distribution</A>
+ (Poland)</LI>
+<LI><A>Best Linux</A> (Finland)</LI>
+</UL>
+<P>For distributions which do not include FreeS/WAN and are not Redhat
+ (which we develop and test on), there is additional information in our<A
+href="#otherdist"> compatibility</A> section.</P>
+<P>The server edition of<A href="http://www.corel.com"> Corel</A> Linux
+ (Canada) also had FreeS/WAN, but Corel have dropped that product line.</P>
+<H3><A name="kernel_dist">Linux kernel distributions</A></H3>
+<UL>
+<LI><A href="http://sourceforge.net/projects/wolk/">Working Overloaded
+ Linux Kernel (WOLK)</A></LI>
+</UL>
+<H3><A name="office_dist">Office server distributions</A></H3>
+<P>FreeS/WAN is also included in several distributions aimed at the
+ market for turnkey business servers:</P>
+<UL>
+<LI><A href="http://www.e-smith.com/">e-Smith</A> (Canada), which has
+ recently been acquired and become the Network Server Solutions group of<A
+href="http://www.mitel.com/"> Mitel Networks</A> (Canada)</LI>
+<LI><A href="http://www.clarkconnect.org/">ClarkConnect</A> from Point
+ Clark Networks (Canada)</LI>
+<LI><A href="http://www.trustix.net/">Trustix Secure Linux</A> (Norway)</LI>
+</UL>
+<H3><A name="fw_dist">Firewall distributions</A></H3>
+<P>Several distributions intended for firewall and router applications
+ include FreeS/WAN:</P>
+<UL>
+<LI>The<A href="http://www.linuxrouter.org/"> Linux Router Project</A>
+ produces a Linux distribution that will boot from a single floppy. The<A
+href="http://leaf.sourceforge.net"> LEAF</A> firewall project provides
+ several different LRP-based firewall packages. At least one of them,
+ Charles Steinkuehler's Dachstein, includes FreeS/WAN with X.509
+ patches.</LI>
+<LI>there are several distributions bootable directly from CD-ROM,
+ usable on a machine without hard disk.
+<UL>
+<LI>Dachstein (see above) can be used this way</LI>
+<LI><A href="http://www.gibraltar.at/">Gibraltar</A> is based on Debian
+ GNU/Linux.</LI>
+<LI>at time of writing,<A href="www.xiloo.com"> Xiloo</A> is available
+ only in Chinese. An English version is expected.</LI>
+</UL>
+</LI>
+<LI><A href="http://www.astaro.com/products/index.html">Astaro Security
+ Linux</A> includes FreeS/WAN. It has some web-based tools for managing
+ the firewall that include FreeS/WAN configuration management.</LI>
+<LI><A href="http://www.linuxwall.de">Linuxwall</A></LI>
+<LI><A href="http://www.smoothwall.org/">Smoothwall</A></LI>
+<LI><A href="http://www.devil-linux.org/">Devil Linux</A></LI>
+<LI>Coyote Linux has a<A href="http://embedded.coyotelinux.com/wolverine/index.php">
+ Wolverine</A> firewall/VPN server</LI>
+</UL>
+<P>There are also several sets of scripts available for managing a
+ firewall which is also acting as a FreeS/WAN IPsec gateway. See this<A href="#rules.pub">
+ list</A>.</P>
+<H3><A name="turnkey">Firewall and VPN products</A></H3>
+<P>Several vendors use FreeS/WAN as the IPsec component of a turnkey
+ firewall or VPN product.</P>
+<P>Software-only products:</P>
+<UL>
+<LI><A href="http://www.linuxmagic.com/vpn/index.html">Linux Magic</A>
+ offer a VPN/Firewall product using FreeS/WAN</LI>
+<LI>The Software Group's<A href="http://www.wanware.com/sentinet/">
+ Sentinet</A> product uses FreeS/WAN</LI>
+<LI><A href="http://www.merilus.com">Merilus</A> use FreeS/WAN in their
+ Gateway Guardian firewall product</LI>
+</UL>
+<P>Products that include the hardware:</P>
+<UL>
+<LI>The<A href="http://www.lasat.com"> LASAT SafePipe[tm]</A> series. is
+ an IPsec box based on an embedded MIPS running Linux with FreeS/WAN and
+ a web-config front end. This company also host our freeswan.org web
+ site.</LI>
+<LI>Merilus<A href="http://www.merilus.com/products/fc/index.shtml">
+ Firecard</A> is a Linux firewall on a PCI card.</LI>
+<LI><A href="http://www.kyzo.com/">Kyzo</A> have a &quot;pizza box&quot; product
+ line with various types of server, all running from flash. One of them
+ is an IPsec/PPTP VPN server</LI>
+<LI><A href="http://www.pfn.com">PFN</A> use FreeS/WAN in some of their
+ products</LI>
+</UL>
+<P><A href="www.rebel.com">Rebel.com</A>, makers of the Netwinder Linux
+ machines (ARM or Crusoe based), had a product that used FreeS/WAN. The
+ company is in receivership so the future of the Netwinder is at best
+ unclear.<A href="#patch"> PKIX patches</A> for FreeS/WAN developed at
+ Rebel are listed in our web links document.</P>
+<H2><A name="docs">Information sources</A></H2>
+<H3><A name="docformats">This HowTo, in multiple formats</A></H3>
+<P>FreeS/WAN documentation up to version 1.5 was available only in HTML.
+ Now we ship two formats:</P>
+<UL>
+<LI>as HTML, one file for each doc section plus a global<A href="toc.html">
+ Table of Contents</A></LI>
+<LI><A href="HowTo.html">one big HTML file</A> for easy searching</LI>
+</UL>
+<P>and provide a Makefile to generate other formats if required:</P>
+<UL>
+<LI><A href="HowTo.pdf">PDF</A></LI>
+<LI><A href="HowTo.ps">Postscript</A></LI>
+<LI><A href="HowTo.txt">ASCII text</A></LI>
+</UL>
+<P>The Makefile assumes the htmldoc tool is available. You can download
+ it from<A href="http://www.easysw.com"> Easy Software</A>.</P>
+<P>All formats should be available at the following websites:</P>
+<UL>
+<LI><A href="http://www.freeswan.org/doc.html">FreeS/WAN project</A></LI>
+<LI><A href="http://www.linuxdoc.org">Linux Documentation Project</A></LI>
+</UL>
+<P>The distribution tarball has only the two HTML formats.</P>
+<P><STRONG>Note:</STRONG> If you need the latest doc version, for
+ example to see if anyone has managed to set up interoperation between
+ FreeS/WAN and whatever, then you should download the current snapshot.
+ What is on the web is documentation as of the last release. Snapshots
+ have all changes I've checked in to date.</P>
+<H3><A name="rtfm">RTFM (please Read The Fine Manuals)</A></H3>
+<P>As with most things on any Unix-like system, most parts of Linux
+ FreeS/WAN are documented in online manual pages. We provide a list of<A href="/mnt/floppy/manpages.html">
+ FreeS/WAN man pages</A>, with links to HTML versions of them.</P>
+<P>The man pages describing configuration files are:</P>
+<UL>
+<LI><A href="/mnt/floppy/manpage.d/ipsec.conf.5.html">ipsec.conf(5)</A></LI>
+<LI><A href="/mnt/floppy/manpage.d/ipsec.secrets.5.html">
+ipsec.secrets(5)</A></LI>
+</UL>
+<P>Man pages for common commands include:</P>
+<UL>
+<LI><A href="/mnt/floppy/manpage.d/ipsec.8.html">ipsec(8)</A></LI>
+<LI><A href="/mnt/floppy/manpage.d/ipsec_pluto.8.html">ipsec_pluto(8)</A>
+</LI>
+<LI><A href="/mnt/floppy/manpage.d/ipsec_newhostkey.8.html">
+ipsec_newhostkey(8)</A></LI>
+<LI><A href="/mnt/floppy/manpage.d/ipsec_auto.8.html">ipsec_auto(8)</A></LI>
+</UL>
+<P>You can read these either in HTML using the links above or with the<VAR>
+ man(1)</VAR> command.</P>
+<P>In the event of disagreement between this HTML documentation and the
+ man pages, the man pages are more likely correct since they are written
+ by the implementers. Please report any such inconsistency on the<A href="#lists">
+ mailing list</A>.</P>
+<H3><A name="text">Other documents in the distribution</A></H3>
+<P>Text files in the main distribution directory are README, INSTALL,
+ CREDITS, CHANGES, BUGS and COPYING.</P>
+<P>The Libdes encryption library we use has its own documentation. You
+ can find it in the library directory..</P>
+<H3><A name="assumptions">Background material</A></H3>
+<P>Throughout this documentation, I write as if the reader had at least
+ a general familiarity with Linux, with Internet Protocol networking,
+ and with the basic ideas of system and network security. Of course that
+ will certainly not be true for all readers, and quite likely not even
+ for a majority.</P>
+<P>However, I must limit amount of detail on these topics in the main
+ text. For one thing, I don't understand all the details of those topics
+ myself. Even if I did, trying to explain everything here would produce
+ extremely long and almost completely unreadable documentation.</P>
+<P>If one or more of those areas is unknown territory for you, there are
+ plenty of other resources you could look at:</P>
+<DL>
+<DT>Linux</DT>
+<DD>the<A href="http://www.linuxdoc.org"> Linux Documentation Project</A>
+ or a local<A href="http://www.linux.org/groups/"> Linux User Group</A>
+ and these<A href="#linux.link"> links</A></DD>
+<DT>IP networks</DT>
+<DD>Rusty Russell's<A href="http://netfilter.samba.org/unreliable-guides/networking-concepts-HOWTO/index.html">
+ Networking Concepts HowTo</A> and these<A href="#IP.background"> links</A>
+</DD>
+<DT>Security</DT>
+<DD>Schneier's book<A href="#secrets"> Secrets and Lies</A> and these<A href="#crypto.link">
+ links</A></DD>
+</DL>
+<P>Also, I do make an effort to provide some background material in
+ these documents. All the basic ideas behind IPsec and FreeS/WAN are
+ explained here. Explanations that do not fit in the main text, or that
+ not everyone will need, are often in the<A href="#ourgloss"> glossary</A>
+, which is the largest single file in this document set. There is also a<A
+href="#background"> background</A> file containing various explanations
+ too long to fit in glossary definitions. All files are heavily
+ sprinkled with links to each other and to the glossary.<STRONG> If some
+ passage makes no sense to you, try the links</STRONG>.</P>
+<P>For other reference material, see the<A href="#biblio"> bibliography</A>
+ and our collection of<A href="web.html#weblinks"> web links</A>.</P>
+<P>Of course, no doubt I get this (and other things) wrong sometimes.
+ Feedback via the<A href="#lists"> mailing lists</A> is welcome.</P>
+<H3><A name="archives">Archives of the project mailing list</A></H3>
+<P>Until quite recently, there was only one FreeS/WAN mailing list, and
+ archives of it were:</P>
+<UL>
+<LI><A href="http://www.sandelman.ottawa.on.ca/linux-ipsec">Canada</A></LI>
+<LI><A href="http://www.nexial.com">Holland</A></LI>
+</UL>
+ The two archives use completely different search engines. You might
+ want to try both.
+<P>More recently we have expanded to five lists, each with its own
+ archive.</P>
+<P><A href="#lists">More information</A> on mailing lists.</P>
+<H3><A name="howto">User-written HowTo information</A></H3>
+<P>Various user-written HowTo documents are available. The ones covering
+ FreeS/WAN-to-FreeS/WAN connections are:</P>
+<UL>
+<LI>Jean-Francois Nadeau's<A href="http://jixen.tripod.com/"> practical
+ configurations</A> document</LI>
+<LI>Jens Zerbst's HowTo on<A href="http://dynipsec.tripod.com/"> Using
+ FreeS/WAN with dynamic IP addresses</A>.</LI>
+<LI>an entry in Kurt Seifried's<A href="http://www.securityportal.com/lskb/kben00000013.html">
+ Linux Security Knowledge Base</A>.</LI>
+<LI>a section of David Ranch's<A href="http://www.ecst.csuchico.edu/~dranch/LINUX/index-linux.html#trinityos">
+ Trinity OS Guide</A></LI>
+<LI>a section in David Bander's book<A href="#bander"> Linux Security
+ Toolkit</A></LI>
+</UL>
+<P>User-wriiten HowTo material may be<STRONG> especially helpful if you
+ need to interoperate with another IPsec implementation</STRONG>. We
+ have neither the equipment nor the manpower to test such
+ configurations. Users seem to be doing an admirable job of filling the
+ gaps.</P>
+<UL>
+<LI>list of user-written<A href="interop.html#otherpub"> interoperation
+ HowTos</A> in our interop document</LI>
+</UL>
+<P>Check what version of FreeS/WAN user-written documents cover. The
+ software is under active development and the current version may be
+ significantly different from what an older document describes.</P>
+<H3><A name="applied">Papers on FreeS/WAN</A></H3>
+<P>Two design documents show team thinking on new developments:</P>
+<UL>
+<LI><A href="opportunism.spec">Opportunistic Encryption</A> by technical
+ lead Henry Spencer and Pluto programmer Hugh Redelemeier</LI>
+<LI>discussion of<A href="http://www.sandelman.ottawa.on.ca/SSW/freeswan/klips2req/">
+ KLIPS redesign</A></LI>
+</UL>
+<P>Both documents are works in progress and are frequently revised. For
+ the latest version, see the<A href="#lists"> design mailing list</A>.
+ Comments should go to that list.</P>
+<P>There is now an<A href="http://www.ietf.org/internet-drafts/draft-richardson-ipsec-opportunistic-06.txt">
+ Internet Draft on Opportunistic Encryption</A> by Michael Richardson,
+ Hugh Redelmeier and Henry Spencer. This is a first step toward getting
+ the protocol standardised so there can be multiple implementations of
+ it. Discussion of it takes place on the<A href="http://www.ietf.org/html.charters/ipsec-charter.html">
+ IETF IPsec Working Group</A> mailing list.</P>
+<P>A number of papers giving further background on FreeS/WAN, or
+ exploring its future or its applications, are also available:</P>
+<UL>
+<LI>Both Henry and Richard gave talks on FreeS/WAN at the 2000<A href="http://www.linuxsymposium.org">
+ Ottawa Linux Symposium</A>.
+<UL>
+<LI>Richard's<A href="http://www.conscoop.ottawa.on.ca/rgb/freeswan/ols2k/">
+ slides</A></LI>
+<LI>Henry's paper</LI>
+<LI>MP3 audio of their talks is available from the<A href="http://www.linuxsymposium.org/">
+ conference page</A></LI>
+</UL>
+</LI>
+<LI><CITE>Moat: A Virtual Private Network Appliances and Services
+ Platform</CITE> is a paper about large-scale (a few 100 links) use of
+ FreeS/WAN in a production application at AT&amp;T Research. It is available
+ in Postscript or PDF from co-author Steve Bellovin's<A href="http://www.research.att.com/~smb/papers/index.html">
+ papers list page</A>.</LI>
+<LI>One of the Moat co-authors, John Denker, has also written
+<UL>
+<LI>a<A href="http://www.av8n.com/vpn/ipsec+routing.htm"> proposal</A>
+ for how future versions of FreeS/WAN might interact with routing
+ protocols</LI>
+<LI>a<A href="http://www.av8n.com/vpn/wishlist.htm"> wishlist</A> of
+ possible new features</LI>
+</UL>
+</LI>
+<LI>Bart Trojanowski's web page has a draft design for<A href="http://www.jukie.net/~bart/linux-ipsec/">
+ hardware acceleration</A> of FreeS/WAN</LI>
+</UL>
+<P>Several of these provoked interesting discussions on the mailing
+ lists, worth searching for in the<A href="#archive"> archives</A>.</P>
+<P>There are also several papers in languages other than English, see
+ our<A href="#otherlang"> web links</A>.</P>
+<H3><A name="licensing">License and copyright information</A></H3>
+<P>All code and documentation written for this project is distributed
+ under either the GNU General Public License (<A href="#GPL">GPL</A>) or
+ the GNU Library General Public License. For details see the COPYING
+ file in the distribution.</P>
+<P>Not all code in the distribution is ours, however. See the CREDITS
+ file for details. In particular, note that the<A href="#LIBDES"> Libdes</A>
+ library and the version of<A href="#MD5"> MD5</A> that we use each have
+ their own license.</P>
+<H2><A name="sites">Distribution sites</A></H2>
+<P>FreeS/WAN is available from a number of sites.</P>
+<H3><A NAME="1_5_1">Primary site</A></H3>
+<P>Our primary site, is at xs4all (Thanks, folks!) in Holland:</P>
+<UL>
+<LI><A href="http://www.xs4all.nl/~freeswan">HTTP</A></LI>
+<LI><A href="ftp://ftp.xs4all.nl/pub/crypto/freeswan">FTP</A></LI>
+</UL>
+<H3><A name="mirrors">Mirrors</A></H3>
+<P>There are also mirror sites all over the world:</P>
+<UL>
+<LI><A href="http://www.flora.org/freeswan">Eastern Canada</A> (limited
+ resouces)</LI>
+<LI><A href="ftp://ludwig.doculink.com/pub/freeswan/">Eastern Canada</A>
+ (has older versions too)</LI>
+<LI><A href="ftp://ntsc.notBSD.org/pub/crypto/freeswan/">Eastern Canada</A>
+ (has older versions too)</LI>
+<LI><A href="ftp://ftp.kame.net/pub/freeswan/">Japan</A></LI>
+<LI><A href="ftp://ftp.futuredynamics.com/freecrypto/FreeSWAN/">Hong
+ Kong</A></LI>
+<LI><A href="ftp://ipsec.dk/pub/freeswan/">Denmark</A></LI>
+<LI><A href="ftp://ftp.net.lut.ac.uk/freeswan">the UK</A></LI>
+<LI><A href="http://storm.alert.sk/comp/mirrors/freeswan/">Slovak
+ Republic</A></LI>
+<LI><A href="http://the.wiretapped.net/security/vpn-tunnelling/freeswan/">
+Australia</A></LI>
+<LI><A href="http://freeswan.technolust.cx/">technolust</A></LI>
+<LI><A href="http://freeswan.devguide.de/">Germany</A></LI>
+<LI>Ivan Moore's<A href="http://snowcrash.tdyc.com/freeswan/"> site</A></LI>
+<LI>the<A href="http://www.cryptoarchive.net/"> Crypto Archive</A> on
+ the<A href="http://www.securityportal.com/"> Security Portal</A> site</LI>
+<LI><A href="http://www.wiretapped.net/">Wiretapped.net</A> in Australia</LI>
+</UL>
+<P>Thanks to those folks as well.</P>
+<H3><A name="munitions">The &quot;munitions&quot; archive of Linux crypto software</A>
+</H3>
+<P>There is also an archive of Linux crypto software called &quot;munitions&quot;,
+ with its own mirrors in a number of countries. It includes FreeS/WAN,
+ though not always the latest version. Some of its sites are:</P>
+<UL>
+<LI><A href="http://munitions.vipul.net/">Germany</A></LI>
+<LI><A href="http://munitions.iglu.cjb.net/">Italy</A></LI>
+<LI><A href="http://munitions2.xs4all.nl/">Netherlands</A></LI>
+</UL>
+<P>Any of those will have a list of other &quot;munitions&quot; mirrors. There is
+ also a CD available.</P>
+<H2><A NAME="1_6">Links to other sections</A></H2>
+<P>For more detailed background information, see:</P>
+<UL>
+<LI><A href="#politics">history and politics</A> of cryptography</LI>
+<LI><A href="#ipsec.detail">IPsec protocols</A></LI>
+</UL>
+<P>To begin working with FreeS/WAN, go to our<A href="quickstart.html#quick.guide">
+ quickstart</A> guide.</P>
+<HR>
+<A NAME="upgrading"></A>
+<H1><A NAME="2">Upgrading to FreeS/WAN 2.x</A></H1>
+<H2><A NAME="2_1">New! Built in Opportunistic connections</A></H2>
+<P>Out of the box, FreeS/WAN 2.x will attempt to encrypt all your IP
+ traffic. It will try to establish IPsec connections for:</P>
+<UL>
+<LI> IP traffic from the Linux box on which you have installed
+ FreeS/WAN, and</LI>
+<LI> outbound IP traffic routed through that Linux box (eg. from a
+ protected subnet).</LI>
+</UL>
+<P>FreeS/WAN 2.x uses<STRONG> hidden, automatically enabled<VAR>
+ ipsec.conf</VAR> connections</STRONG> to do this.</P>
+<P>This behaviour is part of our campaign to get Opportunistic
+ Encryption (OE) widespread in the Linux world, so that any two Linux
+ boxes can encrypt to one another without prearrangement. There's one
+ catch, however: you must<A HREF="#quickstart"> set up a few DNS records</A>
+ to distribute RSA public keys and (if applicable) IPsec gateway
+ information.</P>
+<P>If you start FreeS/WAN before you have set up these DNS records, your
+ connectivity will be slow, and messages relating to the built in
+ connections will clutter your logs. If you are unable to set up DNS for
+ OE, you will wish to<A HREF="#disable_policygroups"> disable the hidden
+ connections</A>.</P>
+<A NAME="upgrading.flagday"></A>
+<H3><A NAME="2_1_1">Upgrading Opportunistic Encryption to 2.01 (or
+ later)</A></H3>
+<P>As of FreeS/WAN 2.01, Opportunistic Encryption (OE) uses DNS TXT
+ resource records (RRs) only (rather than TXT with KEY). This change
+ causes a &quot;flag day&quot;. Users of FreeS/WAN 2.00 (or earlier) OE who are
+ upgrading may need to post additional resource records.</P>
+<P>If you are running<A HREF="#initiate-only"> initiate-only OE</A>, you<EM>
+ must</EM> put up a TXT record in any forward domain as per our<A HREF="#opp.client">
+ quickstart instructions</A>. This replaces your old forward KEY.</P>
+<P> If you are running full OE, you require no updates. You already have
+ the needed TXT record in the reverse domain. However, to facilitate
+ future features, you may also wish to publish that TXT record in a
+ forward domain as instructed<A HREF="#opp.incoming"> here</A>.</P>
+<P>If you are running OE on a gateway (and encrypting on behalf of
+ subnetted boxes) you require no updates. You already have the required
+ TXT record in your gateway's reverse map, and the TXT records for any
+ subnetted boxes require no updating. However, to facilitate future
+ features, you may wish to publish your gateway's TXT record in a
+ forward domain as shown<A HREF="#opp.incoming"> here</A>.</P>
+<P> During the transition, you may wish to leave any old KEY records up
+ for some time. They will provide limited backward compatibility.
+<!--
+For more
+detail on that compatibility, see <A HREF="oe.known-issues">Known Issues with
+OE</A>.
+-->
+</P>
+<H2><A NAME="2_2">New! Policy Groups</A></H2>
+<P>We want to make it easy for you to declare security policy as it
+ applies to IPsec connections.</P>
+<P>Policy Groups make it simple to say:</P>
+<UL>
+<LI>These are the folks I want to talk to in the clear.</LI>
+<LI>These spammers' domains -- I don't want to talk to them at all.</LI>
+<LI>To talk to the finance department, I must use IPsec.</LI>
+<LI>For any other communication, try to encrypt, but it's okay if we
+ can't.</LI>
+</UL>
+<P>FreeS/WAN then implements these policies, creating OE connections if
+ and when needed. You can use Policy Groups along with connections you
+ explicitly define in ipsec.conf.</P>
+<P>For more information, see our<A HREF="policygroups.html"> Policy
+ Group HOWTO</A>.</P>
+<H2><A NAME="2_3">New! Packetdefault Connection</A></H2>
+<P>Free/SWAN 2.x ships with the<STRONG> automatically enabled, hidden
+ connection</STRONG><VAR> packetdefault</VAR>. This configures a
+ FreeS/WAN box as an OE gateway for any hosts located behind it. As
+ mentioned above, you must configure some<A HREF="quickstart.html"> DNS
+ records</A> for OE to work.</P>
+<P>As the name implies, this connection functions as a default. If you
+ have more specific connections, such as policy groups which configure
+ your FreeS/WAN box as an OE gateway for a local subnet, these will
+ apply before<VAR> packetdefault</VAR>. You can view<VAR> packetdefault</VAR>
+'s specifics in<A HREF="manpage.d/ipsec.conf.5.html"> man ipsec.conf</A>
+.</P>
+<H2><A NAME="2_4">FreeS/WAN now disables Reverse Path Filtering</A></H2>
+<P>FreeS/WAN often doesn't work with reverse path filtering. At start
+ time, FreeS/WAN now turns rp_filter off, and logs a warning.</P>
+<P>FreeS/WAN does not turn it back on again. You can do this yourself
+ with a command like:</P>
+<PRE>   echo 1 &gt; /proc/sys/net/ipv4/conf/eth0/rp_filter</PRE>
+<P>For eth0, substitute the interface which FreeS/WAN was affecting.</P>
+<A NAME="ipsec.conf_v2"></A>
+<H2><A NAME="2_5">Revised<VAR> ipsec.conf</VAR></A></H2>
+<H3><A NAME="2_5_1">No promise of compatibility</A></H3>
+<P>The FreeS/WAN team promised config-file compatibility throughout the
+ 1.x series. That means a 1.5 config file can be directly imported into
+ a fresh 1.99 install with no problems.</P>
+<P>With FreeS/WAN 2.x, we've given ourselves permission to make the
+ config file easier to use. The cost: some FreeS/WAN 1.x configurations
+ will not work properly. Many of the new features are, however, backward
+ compatible.</P>
+<H3><A NAME="2_5_2">Most<VAR> ipsec.conf</VAR> files will work fine</A></H3>
+<P>... so long as you paste this line,<STRONG> with no preceding
+ whitespace</STRONG>, at the top of your config file:</P>
+<PRE>    version 2</PRE>
+<H3><A NAME="2_5_3">Backward compatibility patch</A></H3>
+<P>If the new defaults bite you, use<A HREF="ipsec.conf.2_to_1"> this<VAR>
+ ipsec.conf</VAR> fragment</A> to simulate the old default values.</P>
+<H3><A NAME="2_5_4">Details</A></H3>
+<P> We've obsoleted various directives which almost no one was using:</P>
+<PRE>    dump
+    plutobackgroundload
+    no_eroute_pass
+    lifetime
+    rekeystart
+    rekeytries</PRE>
+<P>For most of these, there is some other way to elicit the desired
+ behaviour. See<A HREF="http://lists.freeswan.org/pipermail/design/2002-August/003243.html">
+ this post</A>.</P>
+<P> We've made some settings, which almost everyone was using, defaults.
+ For example:</P>
+<PRE>    interfaces=%defaultroute
+    plutoload=%search
+    plutostart=%search
+    uniqueids=yes</PRE>
+<P>We've also changed some default values to help with OE and Policy
+ Groups:</P>
+<PRE>    authby=rsasig   ## not secret!!!
+    leftrsasigkey=%dnsondemand ## looks up missing keys in DNS when needed.
+    rightrsasigkey=%dnsondemand</PRE>
+<P> Of course, you can still override any defaults by explictly
+ declaring something else in your connection.</P>
+<P><A HREF="http://lists.freeswan.org/pipermail/design/2002-August/003243.html">
+ A post with a list of many ipsec.conf changes.</A>
+<BR><A HREF="manpage.d/ipsec.conf.5.html"> Current ipsec.conf manual.</A>
+</P>
+<A NAME="upgrading.rpms"></A>
+<H3><A NAME="2_5_5">Upgrading from 1.x RPMs to 2.x RPMs</A></H3>
+<P>Note: When upgrading from 1-series to 2-series RPMs,<VAR> rpm -U</VAR>
+ will not work.</P>
+<P>You must instead erase the 1.x RPMs, then install the 2.x set:</P>
+<PRE>    rpm -e freeswan</PRE>
+<PRE>    rpm -e freeswan-module</PRE>
+<P>On erasing, your old<VAR> ipsec.conf</VAR> should be moved to<VAR>
+ ipsec.conf.rpmsave</VAR>. Keep this. You will probably want to copy
+ your existing connections to the end of your new 2.x file.</P>
+<P>Install the RPMs suitable for your kernel version, such as:</P>
+<PRE>    rpm -ivh freeswan-module-2.04_2.4.20_20.9-0.i386.rpm</PRE>
+<PRE>    rpm -ivh freeswan-userland-2.04_2.4.20_20.9-0.i386.rpm</PRE>
+<P>Or, to splice the files:</P>
+<PRE>    cat /etc/ipsec.conf /etc/ipsec.conf.rpmsave &gt; /etc/ipsec.conf.tmp
+    mv /etc/ipsec.conf.tmp /etc/ipsec.conf</PRE>
+<P>Then, remove the redundant<VAR> conn %default</VAR> and<VAR> config
+ setup</VAR> sections. Unless you have done any special configuring
+ here, you'll likely want to remove the 1.x versions. Remove<VAR> conn
+ OEself</VAR>, if present.</P>
+<HR>
+<H1><A name="quickstart">Quickstart Guide to Opportunistic Encryption</A>
+</H1>
+<A name="quick_guide"></A>
+<H2><A name="opp.setup">Purpose</A></H2>
+<P>This page will get you started using Linux FreeS/WAN with
+ opportunistic encryption (OE). OE enables you to set up IPsec tunnels
+ without co-ordinating with another site administrator, and without hand
+ configuring each tunnel. If enough sites support OE, a &quot;FAX effect&quot;
+ occurs, and many of us can communicate without eavesdroppers.</P>
+<H3><A NAME="3_1_1">OE &quot;flag day&quot;</A></H3>
+<P>As of FreeS/WAN 2.01, OE uses DNS TXT resource records (RRs) only
+ (rather than TXT with KEY). This change causes a<A href="http://jargon.watson-net.com/jargon.asp?w=flag+day">
+ &quot;flag day&quot;</A>. Users of FreeS/WAN 2.00 (or earlier) OE who are
+ upgrading may require additional resource records, as detailed in our<A href="#upgrading.flagday">
+ upgrading document</A>. OE setup instructions here are for 2.02 or
+ later.</P>
+<H2><A name="opp.dns">Requirements</A></H2>
+<P>To set up opportunistic encryption, you will need:</P>
+<UL>
+<LI>a Linux box. For OE to the public Internet, this box must NOT be
+ behind<A HREF="#NAT.gloss"> Network Address Translation</A> (NAT).</LI>
+<LI>to install Linux FreeS/WAN 2.02 or later</LI>
+<LI>either control over your reverse DNS (for full opportunism) or the
+ ability to write to some forward domain (for initiator-only).<A HREF="http://www.fdns.net">
+ This free DNS service</A> explicitly supports forward TXT records for
+ FreeS/WAN use.</LI>
+<LI>(for full opportunism) a static IP</LI>
+</UL>
+<P>Note: Currently, only Linux FreeS/WAN supports opportunistic
+ encryption.</P>
+<H2><A name="easy.install">RPM install</A></H2>
+<P>Our instructions are for a recent Red Hat with a 2.4-series stock or
+ Red Hat updated kernel. For other ways to install, see our<A href="#install">
+ install document</A>.</P>
+<H3><A NAME="3_3_1">Download RPMs</A></H3>
+<P>If we have prebuilt RPMs for your Red Hat system, this command will
+ get them:</P>
+<PRE>    ncftpget ftp://ftp.xs4all.nl/pub/crypto/freeswan/binaries/RedHat-RPMs/`uname -r | tr -d 'a-wy-z'`/\*</PRE>
+<P>If that fails, you will need to try<A HREF="install.html"> another
+ install method</A>. Our kernel modules<B> will only work on the Red Hat
+ kernel they were built for</B>, since they are very sensitive to small
+ changes in the kernel.</P>
+<P>If it succeeds, you will have userland tools, a kernel module, and an
+ RPM signing key:</P>
+<PRE>    freeswan-module-2.04_2.4.20_20.9-0.i386.rpm
+    freeswan-userland-2.04_2.4.20_20.9-0.i386.rpm
+    freeswan-rpmsign.asc</PRE>
+<H3><A NAME="3_3_2">Check signatures</A></H3>
+<P>If you're running RedHat 8.x or later, import the RPM signing key
+ into the RPM database:</P>
+<PRE>    rpm --import freeswan-rpmsign.asc</PRE>
+<P>For RedHat 7.x systems, you'll need to add it to your<A HREF="#PGP">
+ PGP</A> keyring:</P>
+<PRE>    pgp -ka freeswan-rpmsign.asc</PRE>
+<P>Check the digital signatures on both RPMs using:</P>
+<PRE>    rpm --checksig freeswan*.rpm </PRE>
+<P>You should see that these signatures are good:</P>
+<PRE>    freeswan-module-2.04_2.4.20_20.9-0.i386.rpm: pgp md5 OK
+    freeswan-userland-2.04_2.4.20_20.9-0.i386.rpm: pgp md5 OK</PRE>
+<H3><A NAME="3_3_3">Install the RPMs</A></H3>
+<P>Become root:</P>
+<PRE>    su</PRE>
+<P>Install your RPMs with:</P>
+<P></P>
+<PRE>    rpm -ivh freeswan*.rpm</PRE>
+<P>If you're upgrading from FreeS/WAN 1.x RPMs, and have problems with
+ that command, see<A HREF="#upgrading.rpms"> this note</A>.</P>
+<P>Then, start FreeS/WAN:</P>
+<PRE>    service ipsec start</PRE>
+<H3><A name="testinstall">Test</A></H3>
+<P>To check that you have a successful install, run:</P>
+<PRE>    ipsec verify</PRE>
+<P>You should see as part of the<VAR> verify</VAR> output:</P>
+<PRE>
+    Checking your system to see if IPsec got installed and started correctly
+    Version check and ipsec on-path                             [OK]
+    Checking for KLIPS support in kernel                        [OK]
+    Checking for RSA private key (/etc/ipsec.secrets)           [OK]
+    Checking that pluto is running                              [OK]
+    ...</PRE>
+<P>If any of these first four checks fails, see our<A href="#install.check">
+ troubleshooting guide</A>.</P>
+<H2><A name="opp.setups.list">Our Opportunistic Setups</A></H2>
+<H3><A NAME="3_4_1">Full or partial opportunism?</A></H3>
+<P>Determine the best form of opportunism your system can support.</P>
+<UL>
+<LI>For<A HREF="#opp.incoming"> full opportunism</A>, you'll need a
+ static IP and and either control over your reverse DNS or an ISP that
+ can add the required TXT record for you.</LI>
+<LI>If you have a dynamic IP, and/or write access to forward DNS only,
+ you can do<A HREF="#opp.client"> initiate-only opportunism</A></LI>
+<LI>To protect traffic bound for real IPs behind your gateway, use<A HREF="#opp.gate">
+ this form of full opportunism</A>.</LI>
+</UL>
+<H2><A name="opp.client">Initiate-only setup</A></H2>
+<H3><A NAME="3_5_1">Restrictions</A></H3>
+<P>When you set up initiate-only Opportunistic Encryption (iOE):</P>
+<UL>
+<LI>there will be<STRONG> no incoming connection requests</STRONG>; you
+ can initiate all the IPsec connections you need.</LI>
+<LI><STRONG>only one machine is visible</STRONG> on your end of the
+ connection.</LI>
+<LI>iOE also protects traffic on behalf of<A HREF="#NAT.gloss"> NATted</A>
+ hosts behind the iOE box.</LI>
+</UL>
+<P>You cannot network a group of initiator-only machines if none of
+ these is capable of responding to OE. If one is capable of responding,
+ you may be able to create a hub topology using routing.</P>
+<H3><A name="forward.dns">Create and publish a forward DNS record</A></H3>
+<H4><A NAME="3_5_2_1">Find a domain you can use</A></H4>
+<P>Find a DNS forward domain (e.g. example.com) where you can publish
+ your key. You'll need access to the DNS zone files for that domain.
+ This is common for a domain you own. Some free DNS providers, such as<A HREF="http://www.fdns.net">
+ this one</A>, also provide this service.</P>
+<P>Dynamic IP users take note: the domain where you place your key need
+ not be associated with the IP address for your system, or even with
+ your system's usual hostname.</P>
+<H4><A NAME="3_5_2_2">Choose your ID</A></H4>
+<P>Choose a name within that domain which you will use to identify your
+ machine. It's convenient if this can be the same as your hostname:</P>
+<PRE>    [root@xy root]# hostname --fqdn
+    xy.example.com</PRE>
+<P>This name in FQDN (fully-qualified domain name) format will be your
+ ID, for DNS key lookup and IPsec negotiation.</P>
+<H4><A NAME="3_5_2_3">Create a forward TXT record</A></H4>
+<P>Generate a forward TXT record containing your system's public key
+ with a command like:</P>
+<PRE>    ipsec showhostkey --txt @xy.example.com</PRE>
+<P>using your chosen ID in place of xy.example.com. This command takes
+ the contents of /etc/ipsec.secrets and reformats it into something
+ usable by ISC's BIND. The result should look like this (with the key
+ data trimmed down for clarity):</P>
+<PRE>
+    ; RSA 2192 bits   xy.example.com   Thu Jan  2 12:41:44 2003
+        IN      TXT     &quot;X-IPsec-Server(10)=@xy.example.com&quot; 
+    &quot;AQOF8tZ2... ...+buFuFn/&quot;
+</PRE>
+<H4><A NAME="3_5_2_4">Publish the forward TXT record</A></H4>
+<P>Insert the record into DNS, or have a system adminstrator do it for
+ you. It may take up to 48 hours for the record to propagate, but it's
+ usually much quicker.</P>
+<H3><A NAME="3_5_3">Test that your key has been published</A></H3>
+<P>Check your DNS work</P>
+<PRE>    ipsec verify --host xy.example.com</PRE>
+<P>As part of the<VAR> verify</VAR> output, you ought to see something
+ like:</P>
+<PRE>    ...
+    Looking for TXT in forward map: xy.example.com          [OK]
+    ...</PRE>
+<P>For this type of opportunism, only the forward test is relevant; you
+ can ignore the tests designed to find reverse records.</P>
+<H3><A NAME="3_5_4">Configure, if necessary</A></H3>
+<P> If your ID is the same as your hostname, you're ready to go.
+ FreeS/WAN will use its<A HREF="policygroups.html"> built-in connections</A>
+ to create your iOE functionality.</P>
+<P>If you have chosen a different ID, you must tell FreeS/WAN about it
+ via<A HREF="manpage.d/ipsec.conf.5.html"><VAR> ipsec.conf</VAR></A>:</P>
+<PRE>    config setup
+        myid=@myname.freedns.example.com</PRE>
+<P>and restart FreeS/WAN:</P>
+<PRE>    service ipsec restart</PRE>
+<P>The new ID will be applied to the built-in connections.</P>
+<P>Note: you can create more complex iOE configurations as explained in
+ our<A HREF="#policygroups"> policy groups document</A>, or disable OE
+ using<A HREF="#disable_policygroups"> these instructions</A>.</P>
+<H3><A NAME="3_5_5">Test</A></H3>
+<P>That's it!<A HREF="#opp.test"> Test your connections</A>.</P>
+<A name="opp.incoming"></A>
+<H2><A NAME="3_6">Full Opportunism</A></H2>
+<P>Full opportunism allows you to initiate and receive opportunistic
+ connections on your machine.</P>
+<A name="incoming.opp.dns"></A>
+<H3><A NAME="3_6_1">Put a TXT record in a Forward Domain</A></H3>
+<P>To set up full opportunism, first<A HREF="#forward.dns"> set up a
+ forward TXT record</A> as for<A HREF="#opp.client"> initiator-only OE</A>
+, using an ID (for example, your hostname) that resolves to your IP. Do
+ not configure<VAR> /etc/ipsec.conf</VAR>, but continue with the
+ instructions for full opportunism, below.</P>
+<P>Note that this forward record is not currently necessary for full OE,
+ but will facilitate future features.</P>
+<A name="incoming.opp.dns"></A>
+<H3><A NAME="3_6_2">Put a TXT record in Reverse DNS</A></H3>
+<P>You must be able to publish your DNS RR directly in the reverse
+ domain. FreeS/WAN will not follow a PTR which appears in the reverse,
+ since a second lookup at connection start time is too costly.</P>
+<H4><A NAME="3_6_2_1">Create a Reverse DNS TXT record</A></H4>
+<P>This record serves to publicize your FreeS/WAN public key. In
+ addition, it lets others know that this machine can receive
+ opportunistic connections, and asserts that the machine is authorized
+ to encrypt on its own behalf.</P>
+<P>Use the command:</P>
+<PRE>    ipsec showhostkey --txt 192.0.2.11</PRE>
+<P>where you replace 192.0.2.11 with your public IP.</P>
+<P>The record (with key shortened) looks like:</P>
+<PRE>    ; RSA 2048 bits  xy.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;</PRE>
+<H4><A NAME="3_6_2_2">Publish your TXT record</A></H4>
+<P>Send these records to your ISP, to be published in your IP's reverse
+ map. It may take up to 48 hours for these to propagate, but usually
+ takes much less time.</P>
+<H3><A NAME="3_6_3">Test your DNS record</A></H3>
+<P>Check your DNS work with</P>
+<PRE>    ipsec verify --host xy.example.com</PRE>
+<P>As part of the<VAR> verify</VAR> output, you ought to see something
+ like:</P>
+<PRE>    ...
+    Looking for TXT in reverse map: 11.2.0.192.in-addr.arpa [OK]
+    ...</PRE>
+<P>which indicates that you've passed the reverse-map test.</P>
+<H3><A NAME="3_6_4">No Configuration Needed</A></H3>
+<P>FreeS/WAN 2.x ships with full OE enabled, so you don't need to
+ configure anything. To enable OE out of the box, FreeS/WAN 2.x uses the
+ policy group<VAR> private-or-clear</VAR>, which creates IPsec
+ connections if possible (using OE if needed), and allows traffic in the
+ clear otherwise. You can create more complex OE configurations as
+ described in our<A HREF="#policygroups"> policy groups document</A>, or
+ disable OE using<A HREF="#disable_policygroups"> these instructions</A>
+.</P>
+<P>If you've previously configured for initiator-only opportunism,
+ remove<VAR> myid=</VAR> from<VAR> config setup</VAR>, so that peer
+ FreeS/WANs will look up your key by IP. Restart FreeS/WAN so that your
+ change will take effect, with</P>
+<PRE>    service ipsec restart</PRE>
+<H3><A NAME="3_6_5">Consider Firewalling</A></H3>
+<P>If you are running a default install of RedHat 8.x, take note: you
+ will need to alter your iptables rule setup to allow IPSec traffic
+ through your firewall. See<A HREF="#simple.rules"> our firewall
+ document</A> for sample<VAR> iptables</VAR> rules.</P>
+<H3><A NAME="3_6_6">Test</A></H3>
+<P>That's it. Now,<A HREF="#opp.test"> test your connection</A>.</P>
+<H3><A NAME="3_6_7">Test</A></H3>
+<P>Instructions are in the next section.</P>
+<H2><A NAME="opp.test">Testing opportunistic connections</A></H2>
+<P>Be sure IPsec is running. You can see whether it is with:</P>
+<PRE>    ipsec setup status</PRE>
+<P>If need be, you can restart it with:</P>
+<PRE>    service ipsec restart</PRE>
+<P>Load a FreeS/WAN test website from the host on which you're running
+ FreeS/WAN. Note: the feds may be watching these sites. Type one of:</P>
+<P></P>
+<PRE>   links oetest.freeswan.org</PRE>
+<PRE>   links oetest.freeswan.nl</PRE>
+
+<!--<PRE>   links oetest.freeswan.ca</PRE>-->
+<P>A positive result looks like this:</P>
+<PRE>
+   You  seem  to  be  connecting  from:  192.0.2.11 which DNS says is:
+   gateway.example.com
+     _________________________________________________________________
+
+   Status E-route
+   OE    enabled    16    192.139.46.73/32    -&gt;    192.0.2.11/32   =&gt;
+   tun0x2097@192.0.2.11
+   OE    enabled    176    192.139.46.77/32    -&gt;   192.0.2.11/32   =&gt;
+   tun0x208a@192.0.2.11
+</PRE>
+<P>If you see this, congratulations! Your OE host or gateway will now
+ encrypt its own traffic whenever it can. For more OE tests, please see
+ our<A HREF="#test.oe"> testing document</A>. If you have difficulty,
+ see our<A HREF="#oe.trouble"> OE troubleshooting tips</A>.</P>
+<H2><A NAME="3_8">Now what?</A></H2>
+<P>Please see our<A HREF="policygroups.html"> policy groups document</A>
+ for more ways to set up Opportunistic Encryption.</P>
+<P>You may also wish to make some<A HREF="config.html"> pre-configured
+ connections</A>.</P>
+<H2><A NAME="3_9">Notes</A></H2>
+<UL>
+<LI>We assume some facts about your system in order to make
+ Opportunistic Encryption easier to configure. For example, we assume
+ that you wish to have FreeS/WAN secure your default interface.</LI>
+<LI>You may change this, and other settings, by altering the<VAR> config
+ setup</VAR> section in<VAR> /etc/ipsec.conf</VAR>.</LI>
+<LI>Note that the built-in connections used to build policy groups do
+ not inherit from<VAR> conn default</VAR>.</LI>
+
+<!--
+<LI>If you do not define your local identity
+(eg. <VAR>leftid</VAR>), this will be the IP address of your default
+FreeS/WAN interface.  
+-->
+<LI> If you fail to define your local identity and do not fill in your
+ reverse DNS entry, you will not be able to use OE.</LI>
+</UL>
+<A NAME="oe.trouble"></A>
+<H2><A NAME="3_10">Troubleshooting OE</A></H2>
+<P>See the OE troubleshooting hints in our<A HREF="#oe.trouble">
+ troubleshooting guide</A>.</P>
+<A NAME="oe.known-issues"></A>
+<H2><A NAME="3_11">Known Issues</A></H2>
+<P>Please see<A HREF="opportunism.known-issues"> this list</A> of known
+ issues with Opportunistic Encryption.</P>
+<HR>
+<H1><A NAME="4">How to Configure Linux FreeS/WAN with Policy Groups</A></H1>
+<A NAME="policygroups"></A>
+<H2><A NAME="4_1">What are Policy Groups?</A></H2>
+<P><STRONG>Policy Groups</STRONG> are an elegant general mechanism to
+ configure FreeS/WAN. They are useful for many FreeS/WAN users.</P>
+<P>In previous FreeS/WAN versions, you needed to configure each IPsec
+ connection explicitly, on both local and remote hosts. This could
+ become complex.</P>
+<P>By contrast, Policy Groups allow you to set local IPsec policy for
+ lists of remote hosts and networks, simply by listing the hosts and
+ networks which you wish to have special treatment in one of several
+ Policy Group files. FreeS/WAN then internally creates the connections
+ needed to implement each policy.</P>
+<P>In the next section we describe our five Base Policy Groups, which
+ you can use to configure IPsec in many useful ways. Later, we will show
+ you how to create an IPsec VPN using one line of configuration for each
+ remote host or network.</P>
+<A NAME="builtin_policygroups"></A>
+<H3><A NAME="4_1_1">Built-In Security Options</A></H3>
+<P>FreeS/WAN offers these Base Policy Groups:</P>
+<DL>
+<DT>private</DT>
+<DD> FreeS/WAN only communicates privately with the listed<A HREF="#CIDR">
+ CIDR</A> blocks. If needed, FreeS/WAN attempts to create a connection
+ opportunistically. If this fails, FreeS/WAN blocks communication.
+ Inbound blocking is assumed to be done by the firewall. FreeS/WAN
+ offers firewall hooks but no modern firewall rules to help with inbound
+ blocking.</DD>
+<DT>private-or-clear</DT>
+<DD> FreeS/WAN prefers private communication with the listed CIDR
+ blocks. If needed, FreeS/WAN attempts to create a connection
+ opportunistically. If this fails, FreeS/WAN allows traffic in the
+ clear.</DD>
+<DT>clear-or-private</DT>
+<DD> FreeS/WAN communicates cleartext with the listed CIDR blocks, but
+ also accepts inbound OE connection requests from them. Also known as<A HREF="#passive.OE">
+ passive OE (pOE)</A>, this policy may be used to create an<A HREF="#responder">
+ opportunistic responder</A>.</DD>
+<DT>clear</DT>
+<DD> FreeS/WAN only communicates cleartext with the listed CIDR blocks.</DD>
+<DT>block</DT>
+<DD>FreeS/WAN blocks traffic to and from and the listed CIDR blocks.
+ Inbound blocking is assumed to be done by the firewall. FreeS/WAN
+ offers firewall hooks but no modern firewall rules to help with inbound
+ blocking.
+<!-- also called "blockdrop".-->
+</DD>
+</DL>
+<A NAME="policy.group.notes"></A>
+<P>Notes:</P>
+<UL>
+<LI>Base Policy Groups apply to communication with this host only.</LI>
+<LI>The most specific rule (whether policy or pre-configured connection)
+ applies. This has several practical applications:
+<UL>
+<LI>If CIDR blocks overlap, FreeS/WAN chooses the most specific
+ applicable block.</LI>
+<LI>This decision also takes into account any pre-configured connections
+ you may have.</LI>
+<LI>If the most specific connection is a pre-configured connection, the
+ following procedure applies. If that connection is up, it will be used.
+ If it is routed, it will be brought up. If it is added, no action will
+ be taken.</LI>
+</UL>
+</LI>
+<LI>Base Policy Groups are created using built-in connections. Details
+ in<A HREF="manpage.d/ipsec.conf.5.html"> man ipsec.conf</A>.</LI>
+<LI>All Policy Groups are bidirectional.<A HREF="src/policy-groups-table.html">
+ This chart</A> shows some technical details. FreeS/WAN does not support
+ one-way encryption, since it can give users a false sense of security.</LI>
+</UL>
+<H2><A NAME="4_2">Using Policy Groups</A></H2>
+<P>The Base Policy Groups which build IPsec connections rely on
+ Opportunistic Encryption. To use the following examples, you must first
+ become OE-capable, as described in our<A HREF="#quickstart"> quickstart
+ guide</A>.<A NAME="example1"></A></P>
+<H3><A NAME="4_2_1">Example 1: Using a Base Policy Group</A></H3>
+<P>Simply place CIDR blocks (<A HREF="#dnswarning">names</A>, IPs or IP
+ ranges) in /etc/ipsec.d/policies/<VAR>[groupname]</VAR>, and reread the
+ policy group files.</P>
+<P>For example, the<VAR> private-or-clear</VAR> policy tells FreeS/WAN
+ to prefer encrypted communication to the listed CIDR blocks. Failing
+ that, it allows talk in the clear.</P>
+<P>To make this your default policy, place<A HREF="#fullnet"> fullnet</A>
+ in the<VAR> private-or-clear</VAR> policy group file:</P>
+<PRE>    [root@xy root]# cat /etc/ipsec.d/policies/private-or-clear
+    # This file defines the set of CIDRs (network/mask-length) to which
+    # communication should be private, if possible, but in the clear otherwise.
+    ....
+    0.0.0.0/0</PRE>
+<P>and reload your policies with</P>
+<PRE>    ipsec auto --rereadgroups</PRE>
+<P>Use<A HREF="#opp.test"> this test</A> to verify opportunistic
+ connections.</P>
+<A NAME="example2"></A>
+<H3><A NAME="4_2_2">Example 2: Defining IPsec Security Policy with
+ Groups</A></H3>
+<P>Defining IPsec security policy with Base Policy Groups is like
+ creating a shopping list: just put CIDR blocks in the appropriate group
+ files. For example:</P>
+<PRE>    [root@xy root]# cd /etc/ipsec.d/policies
+    [root@xy policies]# cat private
+        192.0.2.96/27              # The finance department
+        192.0.2.192/29             # HR
+	192.0.2.12                 # HR gateway
+        irc.private.example.com    # Private IRC server
+  
+    [root@xy policies]# cat private-or-clear
+        0.0.0.0/0                  # My default policy: try to encrypt.
+
+    [root@xy policies]# cat clear
+        192.0.2.18/32              # My POP3 server
+        192.0.2.19/32              # My Web proxy
+
+    [root@xy policies]# cat block
+        spamsource.example.com</PRE>
+<P>To make these settings take effect, type:</P>
+<PRE>    ipsec auto --rereadgroups</PRE>
+<P>Notes:</P>
+<UL>
+<LI>For opportunistic connection attempts to succeed, all participating
+ FreeS/WAN hosts and gateways must be configured for OE.</LI>
+<LI>Examples 3 through 5 show how to implement a detailed<VAR> private</VAR>
+ policy.</LI>
+<LI><A NAME="dnswarning"></A><FONT COLOR="RED"> Warning:</FONT> Using
+ DNS names in policy files and ipsec.conf can be tricky. If the name
+ does not resolve, the policy will not be implemented for that name. It
+ is therefore safer either to use IPs, or to put any critical names in
+ /etc/hosts. We plan to implement periodic DNS retry to help with this.
+<BR> Names are resolved at FreeS/WAN startup, or when the policies are
+ reloaded. Unfortunately, name lookup can hold up the startup process.
+ If you have fast DNS servers, the problem may be less severe.</LI>
+</UL>
+<A HREF="example3"></A>
+<H3><A NAME="4_2_3">Example 3: Creating a Simple IPsec VPN with the<VAR>
+ private</VAR> Group</A></H3>
+<P>You can create an IPsec VPN between several hosts, with only one line
+ of configuration per host, using the<VAR> private</VAR> policy group.</P>
+<P>First, use our<A HREF="quickstart.html"> quickstart guide</A> to set
+ up each participating host with a FreeS/WAN install and OE.</P>
+<P>In one host's<VAR> /etc/ipsec.d/policies/private</VAR>, list the
+ peers to which you wish to protect traffic. For example:</P>
+<PRE>    [root@xy root]# cd /etc/ipsec.d/policies
+    [root@xy policies]# cat private
+        192.0.2.9              # several hosts at example.com
+        192.0.2.11             
+        192.0.2.12                 
+        irc.private.example.com 
+</PRE>
+<P>Copy the<VAR> private</VAR> file to each host. Remove the local host,
+ and add the initial host.</P>
+<PRE>    scp2 /etc/ipsec.d/policies/private root@192.0.2.12:/etc/ipsec.d/policies/private</PRE>
+<P>On each host, reread the policy groups with</P>
+<PRE>    ipsec auto --rereadgroups</PRE>
+<P>That's it! You're configured.</P>
+<P>Test by pinging between two hosts. After a second or two, traffic
+ should flow, and</P>
+<PRE>    ipsec eroute</PRE>
+<P>should yield something like</P>
+<PRE>    192.0.2.11/32   -&gt; 192.0.2.8/32  =&gt; tun0x149f@192.0.2.8</PRE>
+<P>where your host IPs are substituted for 192.0.2.11 and 192.0.2.8.</P>
+<P>If traffic does not flow, there may be an error in your OE setup.
+ Revisit our<A HREF="quickstart.html"> quickstart guide</A>.</P>
+<P>Our next two examples show you how to add subnets to this IPsec VPN.</P>
+<A NAME="example4"></A>
+<H3><A NAME="4_2_4">Example 4: New Policy Groups to Protect a Subnet</A></H3>
+<P>To protect traffic to a subnet behind your FreeS/WAN gateway, you'll
+ need additional DNS records, and new policy groups. To set up the DNS,
+ see our<A HREF="#opp.gate"> quickstart guide</A>. To create five new
+ policy groups for your subnet, copy these connections to<VAR>
+ /etc/ipsec.conf</VAR>. Substitute your subnet's IPs for 192.0.2.128/29.</P>
+<PRE>
+conn private-net
+    also=private  # inherits settings (eg. auto=start) from built in conn
+    leftsubnet=192.0.2.128/29  # your subnet's IPs here
+
+conn private-or-clear-net
+    also=private-or-clear
+    leftsubnet=192.0.2.128/29
+
+conn clear-or-private-net
+    also=clear-or-private
+    leftsubnet=192.0.2.128/29
+
+conn clear-net
+    also=clear
+    leftsubnet=192.0.2.128/29
+
+conn block-net
+    also=block
+    leftsubnet=192.0.2.128/29
+</PRE>
+<P>Copy the gateway's files to serve as the initial policy group files
+ for the new groups:</P>
+<PRE>
+    cp -p /etc/ipsec.d/policies/private /etc/ipsec.d/policies/private-net
+    cp -p /etc/ipsec.d/policies/private-or-clear /etc/ipsec.d/policies/private-or-clear-net
+    cp -p /etc/ipsec.d/policies/clear-or-private /etc/ipsec.d/policies/clear-or-private-net
+    cp -p /etc/ipsec.d/policies/clear /etc/ipsec.d/policies/clear-net
+    cp -p /etc/ipsec.d/policies/block /etc/ipsec.d/policies/block
+</PRE>
+<P><STRONG>Tip: Since a missing policy group file is equivalent to a
+ file with no entries, you need only create files for the connections
+ you'll use.</STRONG></P>
+<P>To test one of your new groups, place the fullnet 0.0.0.0/0 in<VAR>
+ private-or-clear-net</VAR>. Perform the subnet test in<A HREF="#opp.test">
+ our quickstart guide</A>. You should see a connection, and</P>
+<PRE>    ipsec eroute</PRE>
+<P>should include an entry which mentions the subnet node's IP and the
+ OE test site IP, like this:</P>
+<PRE>    192.0.2.131/32   -&gt; 192.139.46.77/32  =&gt; tun0x149f@192.0.2.11</PRE>
+<A HREF="example5"></A>
+<H3><A NAME="4_2_5">Example 5: Adding a Subnet to the VPN</A></H3>
+<P>Suppose you wish to secure traffic to a subnet 192.0.2.192/29 behind
+ a FreeS/WAN box 192.0.2.12.</P>
+<P>First, add DNS entries to configure 192.0.2.12 as an opportunistic
+ gateway for that subnet. Instructions are in our<A HREF="#opp.gate">
+ quickstart guide</A>. Next, create a<VAR> private-net</VAR> group on
+ 192.0.2.12 as described in<A HREF="#example4"> Example 4</A>.</P>
+<P>On each other host, add the subnet 192.0.2.192/29 to<VAR> private</VAR>
+, yielding for example</P>
+<PRE>    [root@xy root]# cd /etc/ipsec.d/policies
+    [root@xy policies]# cat private
+        192.0.2.9              # several hosts at example.com
+        192.0.2.11
+        192.0.2.12             # HR department gateway
+        192.0.2.192/29         # HR subnet
+        irc.private.example.com
+</PRE>
+<P>and reread policy groups with</P>
+<PRE>    ipsec auto --rereadgroups</PRE>
+<P>That's all the configuration you need.</P>
+<P>Test your VPN by pinging from a machine on 192.0.2.192/29 to any
+ other host:</P>
+<PRE>    [root@192.0.2.194]# ping 192.0.2.11</PRE>
+<P>After a second or two, traffic should flow, and</P>
+<PRE>    ipsec eroute</PRE>
+<P>should yield something like</P>
+<PRE>    192.0.2.11/32   -&gt; 192.0.2.194/32  =&gt; tun0x149f@192.0.2.12
+</PRE>
+<P>Key:</P>
+<TABLE>
+<TR><TD>1.</TD><TD>192.0.2.11/32</TD><TD>Local start point of the
+ protected traffic.</TD></TR>
+<TR><TD>2.</TD><TD>192.0.2.194/32</TD><TD>Remote end point of the
+ protected traffic.</TD></TR>
+<TR><TD>3.</TD><TD>192.0.2.12</TD><TD>Remote FreeS/WAN node (gateway or
+ host). May be the same as (2).</TD></TR>
+<TR><TD>4.</TD><TD>[not shown]</TD><TD>Local FreeS/WAN node (gateway or
+ host), where you've produced the output. May be the same as (1).</TD></TR>
+</TABLE>
+<P>For additional assurance, you can verify with a packet sniffer that
+ the traffic is being encrypted.</P>
+<P>Note</P>
+<UL>
+<LI>Because strangers may also connect via OE, this type of VPN may
+ require a stricter firewalling policy than a conventional VPN.</LI>
+</UL>
+<H2><A NAME="4_3">Appendix</A></H2>
+<A NAME="hiddenconn"></A>
+<H3><A NAME="4_3_1">Our Hidden Connections</A></H3>
+<P>Our Base Policy Groups are created using hidden connections. These
+ are spelled out in<A HREF="manpage.d/ipsec.conf.5.html"> man ipsec.conf</A>
+ and defined in<VAR> /usr/local/lib/ipsec/_confread</VAR>.</P>
+<A NAME="custom_policygroups"></A>
+<H3><A NAME="4_3_2">Custom Policy Groups</A></H3>
+<P>A policy group is built using a special connection description in<VAR>
+ ipsec.conf</VAR>, which:</P>
+<UL>
+<LI>is<STRONG> generic</STRONG>. It uses<VAR>
+ right=[%group|%opportunisticgroup]</VAR> rather than specific IPs. The
+ connection is cloned for every name or IP range listed in its Policy
+ Group file.</LI>
+<LI>often has a<STRONG> failure rule</STRONG>. This rule, written<VAR>
+ failureshunt=[passthrough|drop|reject|none]</VAR>, tells FreeS/WAN what
+ to do with packets for these CIDRs if it fails to establish the
+ connection. Default is<VAR> none</VAR>.</LI>
+</UL>
+<P>To create a new group:</P>
+<OL>
+<LI>Create its connection definition in<VAR> ipsec.conf</VAR>.</LI>
+<LI>Create a Policy Group file in<VAR> /etc/ipsec.d/policies</VAR> with
+ the same name as your connection.</LI>
+<LI>Put a CIDR block in that file.</LI>
+<LI>Reread groups with<VAR> ipsec auto --rereadgroups</VAR>.</LI>
+<LI>Test:<VAR> ping</VAR> to activate any OE connection, and view
+ results with<VAR> ipsec eroute</VAR>.</LI>
+</OL>
+<A NAME="disable_oe"></A><A NAME="disable_policygroups"></A>
+<H3><A NAME="4_3_3">Disabling Opportunistic Encryption</A></H3>
+<P>To disable OE (eg. policy groups and packetdefault), cut and paste
+ the following lines to<VAR> /etc/ipsec.conf</VAR>:</P>
+<PRE>conn block
+    auto=ignore
+
+conn private
+    auto=ignore
+
+conn private-or-clear
+    auto=ignore
+
+conn clear-or-private
+    auto=ignore
+
+conn clear
+    auto=ignore
+
+conn packetdefault
+    auto=ignore</PRE>
+<P>Restart FreeS/WAN so that the changes take effect:</P>
+<PRE>    ipsec setup restart</PRE>
+<HR>
+<H1><A NAME="5">FreeS/WAN FAQ</A></H1>
+<P>This is a collection of questions and answers, mostly taken from the
+ FreeS/WAN<A href="mail.html"> mailing list</A>. See the project<A href="http://www.freeswan.org/">
+ web site</A> for more information. All the FreeS/WAN documentation is
+ online there.</P>
+<P>Contributions to the FAQ are welcome. Please send them to the project<A
+href="mail.html"> mailing list</A>.</P>
+<HR>
+<H2><A name="questions">Index of FAQ questions</A></H2>
+<UL>
+<LI><A href="#whatzit">What is FreeS/WAN?</A></LI>
+<LI><A href="#problems">How do I report a problem or seek help?</A></LI>
+<LI><A href="#generic">Can I get ...</A>
+<UL>
+<LI><A href="#lemme_out">... an off-the-shelf system that includes
+ FreeS/WAN?</A></LI>
+<LI><A href="#contractor">... contractors or staff who know FreeS/WAN?</A>
+</LI>
+<LI><A href="#commercial">... commercial support?</A></LI>
+</UL>
+</LI>
+<LI><A href="#release">Release questions</A>
+<UL>
+<LI><A href="#rel.current">What is the current release?</A></LI>
+<LI><A href="#relwhen">When is the next release?</A></LI>
+<LI><A href="#rel.bugs">Are there known bugs in the current release?</A></LI>
+</UL>
+</LI>
+<LI><A href="mod_cons">Modifications and contributions</A>
+<UL>
+<LI><A href="#modify.faq">Can I modify FreeS/WAN to ...?</A></LI>
+<LI><A href="#contrib.faq">Can I contribute to the project?</A></LI>
+<LI><A href="#ddoc.faq">Is there detailed design documentation?</A></LI>
+</UL>
+</LI>
+<LI><A href="#interact">Will FreeS/WAN work in my environment?</A>
+<UL>
+<LI><A href="#interop.faq">Can FreeS/WAN talk to ... ?</A></LI>
+<LI><A href="#old_to_new">Can different FreeS/WAN versions talk to each
+ other?</A></LI>
+<LI><A href="#faq.bandwidth">Is there a limit on throughput?</A></LI>
+<LI><A href="#faq.number">Is there a limit on number of connections?</A></LI>
+<LI><A href="#faq.speed">Is a ... fast enough to handle FreeS/WAN with
+ my loads?</A></LI>
+</UL>
+</LI>
+<LI><A href="#work_on">Will FreeS/WAN work on ...</A>
+<UL>
+<LI><A href="#versions">... my version of Linux?</A></LI>
+<LI><A href="#nonIntel.faq">... non-Intel CPUs?</A></LI>
+<LI><A href="#multi.faq">... multiprocessors?</A></LI>
+<LI><A href="#k.old">... an older kernel?</A></LI>
+<LI><A href="#k.versions">... the latest kernel version?</A></LI>
+<LI><A href="#interface.faq">... unusual network hardware?</A></LI>
+<LI><A href="#vlan">... a VLAN (802.1q) network?</A></LI>
+</UL>
+</LI>
+<LI><A href="#features.faq">Does FreeS/WAN support ...</A>
+<UL>
+<LI><A href="#VPN.faq">... site-to-site VPN applications</A></LI>
+<LI><A href="#warrior.faq">... remote users connecting to a LAN</A></LI>
+<LI><A href="#road.shared.possible">... remote users using shared secret
+ authentication?</A></LI>
+<LI><A href="#wireless.faq">... wireless networks</A></LI>
+<LI><A href="#PKIcert">... X.509 or other PKI certificates?</A></LI>
+<LI><A href="#Radius">... user authentication (Radius, SecureID, Smart
+ Card ...)?</A></LI>
+<LI><A href="#NATtraversal">... NAT traversal</A></LI>
+<LI><A href="#virtID">... assigning a &quot;virtual identity&quot; to a remote
+ system?</A></LI>
+<LI><A href="#noDES.faq">... single DES encryption?</A></LI>
+<LI><A href="#AES.faq">... AES encryption?</A></LI>
+<LI><A href="#other.cipher">... other encryption algorithms?</A></LI>
+</UL>
+</LI>
+<LI><A href="#canI">Can I ...</A>
+<UL>
+<LI><A href="#policy.preconfig">...use policy groups along with
+ explicitly configured connections?</A></LI>
+<LI><A href="#policy.off">...turn off policy groups?</A></LI>
+
+<!--
+      <li><a href="#policy.otherinterface">...use policy groups
+      on an interface other than <VAR>%defaultroute</VAR>?</a></li>
+-->
+<LI><A href="#reload">... reload connection info without restarting?</A></LI>
+<LI><A href="#masq.faq">... use several masqueraded subnets?</A></LI>
+<LI><A href="#dup_route">... use subnets masqueraded to the same
+ addresses?</A></LI>
+<LI><A href="#road.masq">... assign a road warrior an address on my net
+ (a virtual identity)?</A></LI>
+<LI><A href="#road.many">... support many road warriors with one
+ gateway?</A></LI>
+<LI><A href="#road.PSK">... have many road warriors using shared secret
+ authentication?</A></LI>
+<LI><A href="#QoS">... use Quality of Service routing with FreeS/WAN?</A>
+</LI>
+<LI><A href="#deadtunnel">... recognise dead tunnels and shut them down?</A>
+</LI>
+<LI><A href="#demanddial">... build IPsec tunnels over a demand-dialed
+ link?</A></LI>
+<LI><A href="#GRE">... build GRE, L2TP or PPTP tunnels over IPsec?</A></LI>
+<LI><A href="#NetBIOS">... use Network Neighborhood (Samba, NetBIOS)
+ over IPsec?</A></LI>
+</UL>
+</LI>
+<LI><A href="#setup.faq">Life's little mysteries</A>
+<UL>
+<LI><A href="#cantping">I cannot ping ....</A></LI>
+<LI><A href="#forever">It takes forever to ...</A></LI>
+<LI><A href="#route">I send packets to the tunnel with route(8) but they
+ vanish</A></LI>
+<LI><A href="#down_route">When a tunnel goes down, packets vanish</A></LI>
+<LI><A href="#firewall_ate">The firewall ate my packets!</A></LI>
+<LI><A href="#dropconn">Dropped connections</A></LI>
+<LI><A href="#defaultroutegone">Disappearing %defaultroute</A></LI>
+<LI><A href="#tcpdump.faq">TCPdump on the gateway shows strange things</A>
+</LI>
+<LI><A href="#no_trace">Traceroute does not show anything between the
+ gateways</A></LI>
+</UL>
+</LI>
+<LI><A href="#man4debug">Testing in stages (or .... works but ...
+ doesn't)</A>
+<UL>
+<LI><A href="#nomanual">Manually keyed connections don't work</A></LI>
+<LI><A href="#spi_error">One manual connection works, but second one
+ fails</A></LI>
+<LI><A href="#man_no_auto">Manual connections work, but automatic keying
+ doesn't</A></LI>
+<LI><A href="#nocomp">IPsec works, but connections using compression
+ fail</A></LI>
+<LI><A href="#pmtu.broken">Small packets work, but large transfers fail</A>
+</LI>
+<LI><A href="#subsub">Subnet-to-subnet works, but tests from the
+ gateways don't</A></LI>
+</UL>
+</LI>
+<LI><A href="#compile.faq">Compilation problems</A>
+<UL>
+<LI><A href="#gmp.h_missing">gmp.h: No such file or directory</A></LI>
+<LI><A href="#noVM">... virtual memory exhausted</A></LI>
+</UL>
+</LI>
+<LI><A href="#error">Interpreting error messages</A>
+<UL>
+<LI><A href="#route-client">route-client (or host) exited with status 7</A>
+</LI>
+<LI><A href="#unreachable">SIOCADDRT:Network is unreachable</A></LI>
+<LI><A href="#modprobe">ipsec_setup: modprobe: Can't locate moduleipsec</A>
+</LI>
+<LI><A href="#noKLIPS">ipsec_setup: Fatal error, kernel appears to lack
+ KLIPS</A></LI>
+<LI><A href="#noDNS">ipsec_setup: ... failure to fetch key for ... from
+ DNS</A></LI>
+<LI><A href="#dup_address">ipsec_setup: ... interfaces ... and ... share
+ address ...</A></LI>
+<LI><A href="#kflags">ipsec_setup: Cannot adjust kernel flags</A></LI>
+<LI><A href="#message_num">Message numbers (MI3, QR1, et cetera) in
+ Pluto messages</A></LI>
+<LI><A href="#conn_name">Connection names in Pluto error messages</A></LI>
+<LI><A href="#cantorient">Pluto: ... can't orient connection</A></LI>
+<LI><A href="#no.interface">... we have no ipsecN interface for either
+ end of this connection</A></LI>
+<LI><A href="#noconn">Pluto: ... no connection is known</A></LI>
+<LI><A href="#nosuit">Pluto: ... no suitable connection ...</A></LI>
+<LI><A href="#noconn.auth">Pluto: ... no connection has been authorized</A>
+</LI>
+<LI><A href="#noDESsupport">Pluto: ... OAKLEY_DES_CBC is not supported.</A>
+</LI>
+<LI><A href="#notransform">Pluto: ... no acceptable transform</A></LI>
+<LI><A href="#rsasigkey">rsasigkey dumps core</A></LI>
+<LI><A href="#sig4">!Pluto failure!: ... exited with ... signal 4</A></LI>
+<LI><A href="#econnrefused">ECONNREFUSED error message</A></LI>
+<LI><A href="#no_eroute">klips_debug: ... no eroute!</A></LI>
+<LI><A href="#SAused">... trouble writing to /dev/ipsec ... SA already
+ in use</A></LI>
+<LI><A href="#ignore">... ignoring ... payload</A></LI>
+<LI><A href="#unknown_rightcert">unknown parameter name &quot;rightcert&quot;</A></LI>
+</UL>
+</LI>
+<LI><A href="#spam">Why don't you restrict the mailing lists to reduce
+ spam?</A></LI>
+</UL>
+<HR>
+<H2><A name="whatzit">What is FreeS/WAN?</A></H2>
+<P>FreeS/WAN is a Linux implementation of the<A href="#IPSEC"> IPsec</A>
+ protocols, providing security services at the IP (Internet Protocol)
+ level of the network.</P>
+<P>For more detail, see our<A href="intro.html"> introduction</A>
+ document or the FreeS/WAN project<A href="http://www.freeswan.org/">
+ web site</A>.</P>
+<P>To start setting it up, go to our<A href="quickstart.html">
+ quickstart guide</A>.</P>
+<P>Our<A href="web.html"> web links</A> document has information on<A href="#implement">
+ IPsec for other systems</A>.</P>
+<H2><A name="problems">How do I report a problem or seek help?</A></H2>
+<DL>
+<DT>Read our<A href="trouble.html"> troubleshooting</A> document.</DT>
+<DD>
+<P>It may guide you to a solution. If not, see its<A href="#prob.report">
+ problem reporting</A> section.</P>
+<P>Basically, what it says is<STRONG> give us the output from<VAR> ipsec
+ barf</VAR> from both gateways</STRONG>. Without full information, we
+ cannot diagnose a problem. However,<VAR> ipsec barf</VAR> produces a
+ lot of output. If at all possible,<STRONG> please make barfs accessible
+ via the web or FTP</STRONG> rather than sending enormous mail messages.</P>
+</DD>
+<DT><STRONG>Use the<A href="mail.html"> users mailing list</A> for
+ problem reports</STRONG>, rather than mailing developers directly.</DT>
+<DD>
+<UL>
+<LI>This gives you access to more expertise, including users who may
+ have encountered and solved the same problems.</LI>
+<LI>It is more likely to get a quick response. Developers may get behind
+ on email, or even ignore it entirely for a while, but a list message
+ (given a reasonable Subject: line) is certain to be read by a fair
+ number of people within hours.</LI>
+<LI>It may also be important because of<A href="#exlaw"> cryptography
+ export laws</A>. A US citizen who provides technical assistance to
+ foreign cryptographic work might be charged under the arms export
+ regulations. Such a charge would be easier to defend if the discussion
+ took place on a public mailing list than if it were done in private
+ mail.</LI>
+</UL>
+</DD>
+<DT>Try irc.freenode.net#freeswan.</DT>
+<DD>
+<P>FreeS/WAN developers, volunteers and users can often be found there.
+ Be patient and be prepared to provide lots of information to support
+ your question.</P>
+<P>If your question was really interesting, and you found an answer,
+ please share that with the class by posting to the<A href="mail.html">
+ users mailing list</A>. That way others with the same problem can find
+ your answer in the archives.</P>
+</DD>
+<DT>Premium support is also available.</DT>
+<DD>
+<P>See the next several questions.</P>
+</DD>
+</DL>
+<H2><A name="generic">Can I get ...</A></H2>
+<H3><A name="lemme_out">Can I get an off-the-shelf system that includes
+ FreeS/WAN?</A></H3>
+<P>There are a number of Linux distributions or firewall products which
+ include FreeS/WAN. See this<A href="#products"> list</A>. Using one of
+ these, chosen to match your requirements and budget, may save you
+ considerable time and effort.</P>
+<P>If you don't know your requirements, start by reading Schneier's<A href="#secrets">
+ Secrets and Lies</A>. That gives the best overview of security issues I
+ have seen. Then consider hiring a consultant (see next question) to
+ help define your requirements.</P>
+<H3><A name="consultant">Can I hire consultants or staff who know
+ FreeS/WAN?</A></H3>
+<P>If you want the help of a contractor, or to hire staff with FreeS/WAN
+ expertise, you could:</P>
+<UL>
+<LI>check availability in your area through your local Linux User Group
+ (<A href="http://lugww.counter.li.org/">LUG Index</A>)</LI>
+<LI>try asking on our<A href="mail.html"> mailing list</A></LI>
+</UL>
+<P>For companies offerring support, see the next question.</P>
+<H3><A name="commercial">Can I get commercial support?</A></H3>
+<P>Many of the distributions or firewall products which include
+ FreeS/WAN (see this<A href="#products"> list</A>) come with commercial
+ support or have it available as an option.</P>
+<P>Various companies specialize in commercial support of open source
+ software. Our project leader was a founder of the first such company,
+ Cygnus Support. It has since been bought by<A href="http://www.redhat.com">
+ Redhat</A>. Another such firm is<A href="http://www.linuxcare.com">
+ Linuxcare</A>.</P>
+<H2><A name="release">Release questions</A></H2>
+<H3><A name="rel.current">What is the current release?</A></H3>
+<P>The current release is the highest-numbered tarball on our<A href="ftp://ftp.xs4all.nl/pub/crypto/freeswan">
+ distribution site</A>. Almost always, any of<A href="#mirrors"> the
+ mirrors</A> will have the same file, though perhaps not for a day or so
+ after a release.</P>
+<P>Unfortunately, the web site is not always updated as quickly as it
+ should be.</P>
+<H3><A name="relwhen">When is the next release?</A></H3>
+<P>We try to do a release approximately every six to eight weeks.</P>
+<P>If pre-release tests fail and the fix appears complex, or more
+ generally if the code does not appear stable when a release is
+ scheduled, we will just skip that release.</P>
+<P>For serious bugs, we may bring out an extra bug-fix release. These
+ get numbers in the normal release series. For example, there was a bug
+ found in FreeS/WAN 1.6, so we did another release less than two weeks
+ later. The bug-fix release was called 1.7.</P>
+<H3><A name="rel.bugs">Are there known bugs in the current release?</A></H3>
+<P>Any problems we are aware of at the time of a release are documented
+ in the<A href="../BUGS"> BUGS</A> file for that release. You should
+ also look at the<A href="../CHANGES"> CHANGES</A> file.</P>
+<P>Bugs discovered after a release are discussed on the<A href="mail.html">
+ mailing lists</A>. The easiest way to check for any problems in the
+ current code would be to peruse the<A href="http://lists.freeswan.org/pipermail/briefs">
+ List In Brief</A>.</P>
+<H2><A name="mod_cons">Modifications and contributions</A></H2>
+<H3><A name="modify.faq">Can I modify FreeS/WAN to ...?</A></H3>
+<P>You are free to modify FreeS/WAN in any way. See the discussion of<A href="#licensing">
+ licensing</A> in our introduction document.</P>
+<P>Before investing much energy in any such project, we suggest that you</P>
+<UL>
+<LI>check the list of<A href="#patch"> existing patches</A></LI>
+<LI>post something about your project to the<A href="mail.html"> design
+ mailing list</A></LI>
+</UL>
+<P>This may prevent duplicated effort, or lead to interesting
+ collaborations.</P>
+<H3><A name="contrib.faq">Can I contribute to the project?</A></H3>
+ In general, we welcome contributions from the community. Various
+ contributed patches, either to fix bugs or to add features, have been
+ incorporated into our distribution. Other patches, not yet included in
+ the distribution, are listed in our<A href="#patch"> web links</A>
+ section.
+<P>Users have also contributed heavily to documentation, both by
+ creating their own<A href="#howto"> HowTos</A> and by posting things on
+ the<A href="mail.html"> mailing lists</A> which I have quoted in these
+ HTML docs.</P>
+<P>There are, however, some caveats.</P>
+<P>FreeS/WAN is being implemented in Canada, by Canadians, largely to
+ ensure that is it is entirely free of export restrictions. See this<A href="#status">
+ discussion</A>. We<STRONG> cannot accept code contributions from US
+ residents or citizens</STRONG>, not even one-line bugs fixes. The
+ reasons for this were recently discussed extensively on the mailing
+ list, in a thread starting<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/01/msg00111.html">
+ here</A>.</P>
+<P>Not all contributions are of interest to us. The project has a set of
+ fairly ambitious and quite specific goals, described in our<A href="#goals">
+ introduction</A>. Contributions that lead toward these goals are likely
+ to be welcomed enthusiastically. Other contributions may be seen as
+ lower priority, or even as a distraction.</P>
+<P>Discussion of possible contributions takes place on the<A href="mail.html">
+ design mailing list</A>.</P>
+<H3><A name="ddoc.faq">Is there detailed design documentation?</A></H3>
+ There are:
+<UL>
+<LI><A href="rfc.html">RFCs</A> specifying the protocols we implement</LI>
+<LI><A href="manpages.html">man pages</A> for our utilities, library
+ functions and file formats</LI>
+<LI>comments in the source code</LI>
+<LI><A href="index.html">HTML documentation</A> written primarily for
+ users</LI>
+<LI>archived discussions from the<A href="mail.html"> mailing lists</A></LI>
+<LI>other papers mentioned in our<A href="#applied"> introduction</A></LI>
+</UL>
+<P>The only formal design documents are a few papers in the last
+ category above. All the other categories, however, have things to say
+ about design as well.</P>
+<H2><A name="interact">Will FreeS/WAN work in my environment?</A></H2>
+<H3><A name="interop.faq">Can FreeS/WAN talk to ...?</A></H3>
+<P>The IPsec protocols are designed to support interoperation. In
+ theory, any two IPsec implementations should be able to talk to each
+ other. In practice, it is considerably more complex. We have a whole<A href="interop.html">
+ interoperation document</A> devoted to this problem.</P>
+<P>An important part of that document is links to the many<A href="interop.html#otherpub">
+ user-written HowTos</A> on interoperation between FreeS/WAN and various
+ other implementations. Often the users know more than the developers
+ about these issues (and almost always more than me :-), so these
+ documents may be your best resource.</P>
+<H3><A name="old_to_new">Can different FreeS/WAN versions talk to each
+ other?</A></H3>
+<P>Linux FreeS/WAN can interoperate with many IPsec implementations,
+ including earlier versions of Linux FreeS/WAN itself.</P>
+<P>In a few cases, there are some complications. See our<A href="interop.html#oldswan">
+ interoperation</A> document for details.</P>
+<H3><A name="faq.bandwidth">Is there a limit on throughput?</A></H3>
+<P>There is no hard limit, but see below.</P>
+<H3><A name="faq.number">Is there a limit on number of tunnels?</A></H3>
+<P>There is no hard limit, but see next question.</P>
+<H3><A name="faq.speed">Is a ... fast enough to handle FreeS/WAN with my
+ loads?</A></H3>
+<P>A quick summary:</P>
+<DL>
+<DT>Even a limited machine can be useful</DT>
+<DD>A 486 can handle a T1, ADSL or cable link, though the machine may be
+ breathing hard.</DD>
+<DT>A mid-range PC (say 800 MHz with good network cards) can do a lot of
+ IPsec</DT>
+<DD>With up to roughly 50 tunnels and aggregate bandwidth of 20 Megabits
+ per second, it willl have cycles left over for other tasks.</DD>
+<DT>There are limits</DT>
+<DD>Even a high end CPU will not come close to handling a fully loaded
+ 100 Mbit/second Ethernet link.
+<P>Beyond about 50 tunnels it needs careful management.</P>
+</DD>
+</DL>
+<P>See our<A href="performance.html"> FreeS/WAN performance</A> document
+ for details.</P>
+<H2><A name="work_on">Will FreeS/WAN work on ... ?</A></H2>
+<H3><A name="versions">Will FreeS/WAN run on my version of Linux?</A></H3>
+<P>We build and test on Redhat distributions, but FreeS/WAN runs just
+ fine on several other distributions, sometimes with minor fiddles to
+ adapt to the local environment. Details are in our<A href="#otherdist">
+ compatibility</A> document. Also, some distributions or products come
+ with<A href="#products"> FreeS/WAN included</A>.</P>
+<H3><A name="nonIntel.faq">Will FreeS/WAN run on non-Intel CPUs?</A></H3>
+<P>FreeS/WAN is<STRONG> intended to run on all CPUs Linux supports</STRONG>
+. We know of it being used in production on x86, ARM, Alpha and MIPS. It
+ has also had successful tests on PPC and SPARC, though we don't know of
+ actual use there. Details are in our<A href="#CPUs"> compatibility</A>
+ document.</P>
+<H3><A name="multi.faq">Will FreeS/WAN run on multiprocessors?</A></H3>
+<P>FreeS/WAN is designed to work on any SMP architecture Linux supports,
+ and has been tested successfully on at least dual processor Intel
+ architecture machines. Details are in our<A href="#multiprocessor">
+ compatibility</A> document.</P>
+<H3><A name="k.old">Will FreeS/WAN work on an older kernel?</A></H3>
+<P>It might, but we strongly recommend using a recent 2.2 or 2.4 series
+ kernel. Sometimes the newer versions include security fixes which can
+ be quite important on a gateway.</P>
+<P>Also, we use recent kernels for development and testing, so those are
+ better tested and, if you do encounter a problem, more easily
+ supported. If something breaks applying recent FreeS/WAN patches to an
+ older kernel, then &quot;update your kernel&quot; is almost certain to be the
+ first thing we suggest. It may be the only suggestion we have.</P>
+<P>The precise kernel versions supported by a particular FreeS/WAN
+ release are given in the<A href="XX"> README</A> file of that release.</P>
+<P>See the following question for more on kernels.</P>
+<H3><A name="k.versions">Will FreeS/WAN run on the latest kernel
+ version?</A></H3>
+<P>Sometimes yes, but quite often, no.</P>
+<P>Kernel versions supported are given in the<A href="../README"> README</A>
+ file of each FreeS/WAN release. Typically, they are whatever production
+ kernels were current at the time of our release (or shortly before; we
+ might release for kernel<VAR> n</VAR> just as Linus releases<VAR> n+1</VAR>
+). Often FreeS/WAN will work on slightly later kernels as well, but of
+ course this cannot be guaranteed.</P>
+<P>For example, FreeS/WAN 1.91 was released for kernels 2.2.19 or 2.4.5,
+ the current kernels at the time. It also worked on 2.4.6, 2.4.7 and
+ 2.4.8, but 2.4.9 had changes that caused compilation errors if it was
+ patched with FreeS/WAN 1.91.</P>
+<P>When such changes appear, we put a fix in the FreeS/WAN snapshots,
+ and distribute it with our next release. However, this is not a high
+ priority for us, and it may take anything from a few days to several
+ weeks for such a problem to find its way to the top of our kernel
+ programmer's To-Do list. In the meanwhile, you have two choices:</P>
+<UL>
+<LI>either stick with a slightly older kernel, even if it is not the
+ latest and greatest. This is recommended for production systems; new
+ versions may have new bugs.</LI>
+<LI>or fix the problem yourself and send us a patch, via the<A href="mail.html">
+ Users mailing list</A>.</LI>
+</UL>
+<P>We don't even try to keep up with kernel changes outside the main 2.2
+ and 2.4 branches, such as the 2.4.x-ac patched versions from Alan Cox
+ or the 2.5 series of development kernels. We'd rather work on
+ developing the FreeS/WAN code than on chasing these moving targets. We
+ are, however, happy to get patches for problems discovered there.</P>
+<P>See also the<A href="install.html#choosek"> Choosing a kernel</A>
+ section of our installation document.</P>
+<H3><A name="interface.faq">Will FreeS/WAN work on unusual network
+ hardware?</A></H3>
+<P>IPsec is designed to work over any network that IP works over, and
+ FreeS/WAN is intended to work over any network interface hardware that
+ Linux supports.</P>
+<P>If you have working IP on some unusual interface -- perhaps Arcnet,
+ Token Ring, ATM or Gigabit Ethernet -- then IPsec should &quot;just work&quot;.</P>
+<P>That said, practice is sometimes less tractable than theory. Our
+ testing is done almost entirely on:</P>
+<UL>
+<LI>10 or 100 Mbit Ethernet</LI>
+<LI>ADSL or cable connections, with and without PPPoE</LI>
+<LI>IEEE 802.11 wireless LANs (see<A href="#wireless.faq"> below</A>)</LI>
+</UL>
+<P>If you have some other interface, especially an uncommon one, it is
+ entirely possible you will get bitten either by a FreeS/WAN bug which
+ our testing did not turn up, or by a bug in the driver that shows up
+ only with our loads.</P>
+<P>If IP works on your interface and FreeS/WAN doesn't, seek help on the<A
+href="mail.html"> mailing lists</A>.</P>
+<P>Another FAQ section describes<A href="#pmtu.broken"> MTU problems</A>
+. These are a possibility for some interfaces.</P>
+<H3><A name="vlan">Will FreeS/WAN work on a VLAN (802.1q) network?</A></H3>
+<P> Yes, FreeSwan works fine, though some network drivers have problems
+ with jumbo sized ethernet frames. If you used interfaces=%defaultroute
+ you do not need to change anything, but if you specified an interface
+ (eg eth0) then remember you must change that to reflect the VLAN
+ interface (eg eth0.2 for VLAN ID 2).</P>
+<P> The &quot;eepro100&quot; module is known to be broken, use the e100 driver for
+ those cards instead (included in 2.4 as 'alternative driver' for the
+ Intel EtherExpressPro/100.</P>
+<P> You do not need to change any MTU setting (those are workarounds
+ that are only needed for buggy drivers)</P>
+<P><EM>This FAQ contributed by Paul Wouters.</EM></P>
+<H2><A name="features.faq">Does FreeS/WAN support ...</A></H2>
+<P>For a discussion of which parts of the IPsec specifications FreeS/WAN
+ does and does not implement, see our<A href="#spec"> compatibility</A>
+ document.</P>
+<P>For information on some often-requested features, see below.</P>
+<H3><A name="VPN.faq"></A>Does FreeS/WAN support site-to-site VPN (<A HREF="#VPN">
+Virtual Private Network</A>) applications?</H3>
+<P>Absolutely. See this FreeS/WAN-FreeS/WAN<A HREF="config.html">
+ configuration example</A>. If only one site is using FreeS/WAN, there
+ may be a relevant HOWTO on our<A HREF="interop.html"> interop page</A>.</P>
+<H3><A name="warrior.faq">Does FreeS/WAN support remote users connecting
+ to a LAN?</A></H3>
+<P>Yes. We call the remote users &quot;Road Warriors&quot;. Check out our
+ FreeS/WAN-FreeS/WAN<A HREF="#config.rw"> Road Warrior Configuration
+ Example</A>.</P>
+<P>If your Road Warrior is a Windows or Mac PC, you may need to install
+ an IPsec implementation on that machine. Our<A HREF="interop.html">
+ interop</A> page lists many available brands, and features links to
+ several HOWTOs.</P>
+<H3><A name="road.shared.possible">Does FreeS/WAN support remote users
+ using shared secret authentication?</A></H3>
+<P><STRONG>Yes, but</STRONG> there are severe restrictions, so<STRONG>
+ we strongly recommend using</STRONG><A href="#RSA"><STRONG> RSA</STRONG>
+</A><STRONG> keys for</STRONG><A href="#authentication"><STRONG>
+ authentication</STRONG></A><STRONG> instead</STRONG>.</P>
+<P>See this<A href="#road.PSK"> FAQ question</A>.</P>
+<H3><A name="wireless.faq">Does FreeS/WAN support wireless networks?</A></H3>
+<P>Yes, it is a common practice to use IPsec over wireless networks
+ because their built-in encryption,<A href="#WEP"> WEP</A>, is insecure.</P>
+<P>There is some<A href="#wireless.config"> discussion</A> in our
+ advanced configuration document. See also the<A HREF="http://www.wavesec.org">
+ WaveSEC site</A>.</P>
+<H3><A name="PKIcert">Does FreeS/WAN support X.509 or other PKI
+ certificates?</A></H3>
+<P>Vanilla FreeS/WAN does not support X.509, but Andreas Steffen and
+ others have provided a popular, well-supported X.509 patch.</P>
+<UL>
+<LI><A HREF="http://www.strongsec.com/freeswan">patch</A></LI>
+<LI><A HREF="http://www.freeswan.ca">Super FreeS/WAN</A> incorporates
+ this and other user-contributed patches.</LI>
+<LI> Kai Martius'<A HREF="http://www.strongsec.com/freeswan/install.htm">
+ X.509 Installation and Configuration Guide</A></LI>
+</UL>
+<P> Linux FreeS/WAN features<A HREF="quickstart.html"> Opportunistic
+ Encryption</A>, an alternative Public Key Infrastructure based on
+ Secure DNS.</P>
+<H3><A name="Radius">Does FreeS/WAN support user authentication (Radius,
+ SecureID, Smart Card...)?</A></H3>
+<P>Andreas Steffen's<A HREF="http://www.strongsec.com/freeswan"> X.509
+ patch</A> (v. 1.42+) supports Smart Cards. The patch does not ship with
+ vanilla FreeS/WAN, but will be incorporated into<A HREF="http://www.freeswan.ca/">
+ Super FreeS/WAN 2.01+</A>. The patch implements the PCKS#15
+ Cryptographic Token Information Format Standard, using the OpenSC
+ smartcard library functions.</P>
+<P>Older news:</P>
+<P>A user-supported patch to FreeS/WAN 1.3, for smart card style
+ authentication, is available on<A HREF="http://alcatraz.webcriminals.com/~bastiaan/ipsec">
+ Bastiaan's site</A>. It supports skeyid and ibutton. This patch is not
+ part of Super FreeS/WAN.</P>
+<P>For a while progress on this front was impeded by a lack of standard.
+ The IETF<A href="http://www.ietf.org/html.charters/ipsra-charter.html">
+ working group</A> has now nearly completed its recommended solution to
+ the problem; meanwhile several vendors have implemented various things.</P>
+
+<!--
+<p>The <a href="web.html#patch">patches</a> section of our web links document
+has links to some user work on this.</p>
+-->
+<P>Of course, there are various ways to avoid any requirement for user
+ authentication in IPsec. Consider the situation where road warriors
+ build IPsec tunnels to your office net and you are considering
+ requiring user authentication during tunnel negotiation. Alternatives
+ include:</P>
+<UL>
+<LI>If you can trust the road warrior machines, then set them up so that
+ only authorised users can create tunnels. If your road warriors use
+ laptops, consider the possibility of theft.</LI>
+<LI>If the tunnel only provides access to particular servers and you can
+ trust those servers, then set the servers up to require user
+ authentication.</LI>
+</UL>
+<P>If either of those is trustworthy, it is not clear that you need user
+ authentication in IPsec.</P>
+<H3><A name="NATtraversal">Does FreeS/WAN support NAT traversal?</A></H3>
+<P>Vanilla FreeS/WAN does not, but thanks to Mathieu Lafon and Arkoon
+ Network Security, there's a patch to support this.</P>
+<UL>
+<LI><A HREF="http://open-source.arkoon.net">patch and documentation</A></LI>
+<LI><A HREF="http://www.freeswan.ca">Super FreeS/WAN</A> incorporates
+ this and other user-contributed patches.</LI>
+</UL>
+<P>The NAT traversal patch has some issues with PSKs, so you may wish to
+ authenticate with RSA keys, or X.509 (requires a patch which is also
+ included in Super FreeS/WAN). Doing the latter also has advantages when
+ dealing with large numbers of clients who may be behind NAT; instead of
+ having to make an individual Roadwarrior connection for each virtual
+ IP, you can use the &quot;rightsubnetwithin&quot; parameter to specify a range.
+ See<A HREF="http://www.strongsec.com/freeswan/install.htm#section_4.4">
+ these<VAR> rightsubnetwithin</VAR> instructions</A>.</P>
+<H3><A name="virtID">Does FreeS/WAN support assigning a &quot;virtual
+ identity&quot; to a remote system?</A></H3>
+<P>Some IPsec implementations allow you to make the source address on
+ packets sent by a Road Warrior machine be something other than the
+ address of its interface to the Internet. This is sometimes described
+ as assigning a virtual identity to that machine.</P>
+<P>FreeS/WAN does not directly support this, but it can be done. See
+ this<A href="#road.masq"> FAQ question</A>.</P>
+<H3><A name="noDES.faq">Does FreeS/WAN support single DES encryption?</A>
+</H3>
+<P><STRONG>No</STRONG>, single DES is not used either at the<A href="#IKE">
+ IKE</A> level for negotiating connections or at the<A href="#IPSEC">
+ IPsec</A> level for actually building them.</P>
+<P>Single DES is<A href="#desnotsecure"> insecure</A>. As we see it, it
+ is more important to deliver real security than to comply with a
+ standard which has been subverted into allowing use of inadequate
+ methods. See this<A href="#weak"> discussion</A>.</P>
+<P>If you want to interoperate with an IPsec implementation which offers
+ only DES, see our<A href="interop.html#noDES"> interoperation</A>
+ document.</P>
+<H3><A name="AES.faq">Does FreeS/WAN support AES encryption?</A></H3>
+<P><A href="#AES">AES</A> is a new US government<A href="#block"> block
+ cipher</A> standard to replace the obsolete<A href="#DES"> DES</A>.</P>
+<P>At time of writing (March 2002), the FreeS/WAN distribution does not
+ yet support AES but user-written<A href="#patch"> patches</A> are
+ available to add it. Our kernel programmer is working on integrating
+ those patches into the distribution, and there is active discussion of
+ this on the design mailimg list.</P>
+<H3><A name="other.cipher">Does FreeS/WAN support other encryption
+ algorithms?</A></H3>
+<P>Currently<A href="#3DES"> triple DES</A> is the only cipher
+ supported. AES will almost certainly be added (see previous question),
+ and it is likely that in the process we will also add the other two AES
+ finalists with open licensing, Twofish and Serpent.</P>
+<P>We are extremely reluctant to add other ciphers. This would make both
+ use and maintenance of FreeS/WAN more complex without providing any
+ clear benefit. Complexity is emphatically not desirable in a security
+ product.</P>
+<P>Various users have written patches to add other ciphers. We provide<A href="#patch">
+ links</A> to these.</P>
+<H2><A name="canI">Can I ...</A></H2>
+<H3><A name="policy.preconfig">Can I use policy groups along with
+ explicitly configured connections?</A></H3>
+<P>Yes, you can, so long as you pay attention to the selection rule,
+ which can be summarized &quot;the most specific connection wins&quot;. We
+ describe the rule in our<A HREF="#policy.group.notes"> policy groups</A>
+ document, and provide a more technical explanation in<A HREF="manpage.d/ipsec.conf.5.html">
+ man ipsec.conf</A>.</P>
+<P>A good guideline: If you have a regular connection defined in<VAR>
+ ipsec.conf</VAR>, ensure that a subset of that connection is not listed
+ in a less restrictive policy group. Otherwise, FreeS/WAN will use the
+ subset, with its more specific source/destination pair.</P>
+<P>Here's an example. Suppose you are the system administrator at
+ 192.0.2.2. You have this connection in ipsec.conf:<VAR> ipsec.conf</VAR>
+:</P>
+<PRE>conn net-to-net
+    left=192.0.2.2           # you are here
+    right=192.0.2.8
+    rightsubnet=192.0.2.96/27
+    ....
+</PRE>
+<P>If you then place a host or net within<VAR> rightsubnet</VAR>, (let's
+ say 192.0.2.98) in<VAR> private-or-clear</VAR>, you may find that
+ 192.0.2.2 at times communicates in the clear with 192.0.2.98. That's
+ consistent with the rule, but may be contrary to your expectations.</P>
+<P>On the other hand, it's safe to put a larger subnet in a less
+ restrictive policy group file. If<VAR> private-or-clear</VAR> contains
+ 192.0.2.0/24, then the more specific<VAR> net-to-net</VAR> connection
+ is used for any communication to 192.0.2.96/27. The more general policy
+ applies only to communication with hosts or subnets in 192.0.2.0/24
+ without a more specific policy or connection.</P>
+<H3><A name="policy.off">Can I turn off policy groups?</A></H3>
+<P>Yes. Use<A HREF="#disable_policygroups"> these instructions</A>.</P>
+
+<!--
+<h3><a name="policy.otherinterface">Can I use policy groups
+ on an interface other than <VAR>%defaultroute</VAR>?</a></h3>
+
+<p>??<p>
+-->
+<H3><A name="reload">Can I reload connection info without restarting?</A>
+</H3>
+<P>Yes, you can do this. Here are the details, in a mailing list message
+ from Pluto programmer Hugh Redelmeier:</P>
+<PRE>| How can I reload config's without restarting all of pluto and klips?  I am using
+| FreeSWAN -&gt; PGPNet in a medium sized production environment, and would like to be
+| able to add new connections ( i am using include config/* ) without dropping current
+| SA's.
+| 
+| Can this be done?
+| 
+| If not, are there plans to add this kind of feature?
+
+        ipsec auto --add whatever
+This will look in the usual place (/etc/ipsec.conf) for a conn named
+whatever and add it.
+
+If you added new secrets, you need to do
+        ipsec auto --rereadsecrets
+before Pluto needs to know those secrets.
+
+| I have looked (perhaps not thoroughly enough tho) to see how to do this:
+
+There may be more bits to look for, depending on what you are trying
+to do.</PRE>
+<P>Another useful command here is<VAR> ipsec auto --replace &lt;conn_name&gt;</VAR>
+ which re-reads data for a named connection.</P>
+<H3><A name="masq.faq">Can I use several masqueraded subnets?</A></H3>
+<P>Yes. This is done all the time. See the discussion in our<A href="config.html#route_or_not">
+ setup</A> document. The only restriction is that the subnets on the two
+ ends must not overlap. See the next question.</P>
+<P>Here is a mailing list message on the topic. The user incorrectly
+ thinks you need a 2.4 kernel for this -- actually various people have
+ been doing it on 2.0 and 2.2 for quite some time -- but he has it right
+ for 2.4.</P>
+<PRE>Subject: Double NAT and freeswan working :)
+   Date: Sun, 11 Mar 2001
+   From: Paul Wouters &lt;paul@xtdnet.nl&gt;
+
+Just to share my pleasure, and make an entry for people who are searching
+the net on how to do this. Here's the very simple solution to have a double
+NAT'ed network working with freeswan. (Not sure if this is old news, but I'm
+not on the list (too much spam) and I didn't read this in any HOWTO/FAQ/doc
+on the freeswan site yet (Sandy, put it in! :)
+
+10.0.0.0/24 --- 10.0.0.1 a.b.c.d  ---- a.b.c.e {internet} ----+
+                                                              |
+10.0.1.0/24 --- 10.0.1.1 f.g.h.i  ---- f.g.h.j {internet} ----+
+
+the goal is to have the first network do a VPN to the second one, yet also
+have NAT in place for connections not destinated for the other side of the
+NAT. Here the two Linux security gateways have one real IP number (cable
+modem, dialup, whatever.
+
+The problem with NAT is you don't want packets from 10.*.*.* to 10.*.*.*
+to be NAT'ed. While with Linux 2.2, you can't, with Linux 2.4 you can.
+
+(This has been tested and works for 2.4.2 with Freeswan snapshot2001mar8b)
+
+relevant parts of /etc/ipsec.conf:
+
+        left=f.g.h.i
+        leftsubnet=10.0.1.0/24
+        leftnexthop=f.g.h.j
+        leftfirewall=yes
+        leftid=@firewall.netone.nl
+        leftrsasigkey=0x0........
+        right=a.b.c.d
+        rightsubnet=10.0.0.0/24
+        rightnexthop=a.b.c.e
+        rightfirewall=yes
+        rightid=@firewall.nettwo.nl
+        rightrsasigkey=0x0......
+        # To authorize this connection, but not actually start it, at startup,
+        # uncomment this.
+        auto=add
+
+and now the real trick. Setup the NAT correctly on both sites:
+
+iptables -t nat -F
+iptables -t nat -A POSTROUTING -o eth0 -d \! 10.0.0.0/8 -j MASQUERADE
+
+This tells the NAT code to only do NAT for packets with destination other then
+10.* networks. note the backslash to mask the exclamation mark to protect it
+against the shell.
+
+Happy painting :)
+
+Paul</PRE>
+<H3><A name="dup_route">Can I use subnets masqueraded to the same
+ addresses?</A></H3>
+<P><STRONG>No.</STRONG> The notion that IP addresses are unique is one
+ of the fundamental principles of the IP protocol. Messing with it is
+ exceedingly perilous.</P>
+<P>Fairly often a situation comes up where a company has several
+ branches, all using the same<A href="#non-routable"> non-routable
+ addresses</A>, perhaps 192.168.0.0/24. This works fine as long as those
+ nets are kept distinct. The<A href="#masq"> IP masquerading</A> on
+ their firewalls ensures that packets reaching the Internet carry the
+ firewall address, not the private address.</P>
+<P>This can break down when IPsec enters the picture. FreeS/WAN builds a
+ tunnel that pokes through both masquerades and delivers packets from<VAR>
+ leftsubnet</VAR> to<VAR> rightsubnet</VAR> and vice versa. For this to
+ work, the two subnets<EM> must</EM> be distinct.</P>
+<P>There are several solutions to this problem.</P>
+<P>Usually, you<STRONG> re-number the subnets</STRONG>. Perhaps the
+ Vancouver office becomes 192.168.101.0/24, Calgary 192.168.102.0/24 and
+ so on. FreeS/WAN can happily handle this. With, for example<VAR>
+ leftsubnet=192.168.101.0/24</VAR> and<VAR> rightsubnet=192.168.102.0/24</VAR>
+ in a connection description, any machine in Calgary can talk to any
+ machine in Vancouver. If you want to be more restrictive and use
+ something like<VAR> leftsubnet=192.168.101.128/25</VAR> and<VAR>
+ rightsubnet=192.168.102.240/28</VAR> so only certain machines on each
+ end have access to the tunnel, that's fine too.</P>
+<P>You could also<STRONG> split the subnet</STRONG> into smaller ones,
+ for example using<VAR> 192.168.1.0/25</VAR> in Vancouver and<VAR>
+ rightsubnet=192.168.0.128/25</VAR> in Calgary.</P>
+<P>Alternately, you can just<STRONG> give up routing</STRONG> directly
+ to machines on the subnets. Omit the<VAR> leftsubnet</VAR> and<VAR>
+ rightsubnet</VAR> parameters from your connection descriptions. Your
+ IPsec tunnels will then run between the public interfaces of the two
+ firewalls. Packets will be masqueraded both before they are put into
+ tunnels and after they emerge. Your Vancouver client machines will see
+ only one Calgary machine, the firewall.</P>
+<H3><A name="road.masq">Can I assign a road warrior an address on my net
+ (a virtual identity)?</A></H3>
+<P>Often it would be convenient to be able to give a Road Warrior an IP
+ address which appears to be on the local network. Some IPsec
+ implementations have support for this, sometimes calling the feature
+ &quot;virtual identity&quot;.</P>
+<P>Currently (Sept 2002) FreeS/WAN does not support this, and we have no
+ definite plans to add it. The difficulty is that is not yet a standard
+ mechanism for it. There is an Internet Draft for a method of doing it
+ using<A href="#DHCP"> DHCP</A> which looks promising. FreeS/WAN may
+ support that in a future release.</P>
+<P>In the meanwhile, you can do it yourself using the Linux iproute2(8)
+ facilities. Details are in<A href="http://www.av8n.com/vpn/iproute2.htm">
+ this paper</A>.</P>
+<P>Another method has also been discussed on the mailing list.:</P>
+<UL>
+<LI>You can use a variant of the<A href="#extruded.config"> extruded
+ subnet</A> procedure.</LI>
+<LI>You have to avoid having the road warrior's assigned address within
+ the range you actually use at home base. See previous question.</LI>
+<LI>On the other hand, you want the roadwarrior's address to be within
+ the range that<EM> seems</EM> to be on your network.</LI>
+</UL>
+<P>For example, you might have:</P>
+<DL>
+<DT>leftsubnet=a.b.c.0/25</DT>
+<DD>head office network</DD>
+<DT>rightsubnet=a.b.c.129/32</DT>
+<DD>extruded to a road warrior. Note that this is not in a.b.c.0/25</DD>
+<DT>a.b.c.0/24</DT>
+<DD>whole network, including both the above</DD>
+</DL>
+<P>You then set up routing so that the office machines use the IPsec
+ gateway as their route to a.b.c.128/25. The leftsubnet parameter tells
+ the road warriors to use tunnels to reach a.b.c.0/25, so you should
+ have two-way communication. Depending or your network and applications,
+ there may be some additional work to do on DNS or Windows configuration</P>
+<H3><A name="road.many">Can I support many road warriors with one
+ gateway?</A></H3>
+<P>Yes. This is easily done, using</P>
+<DL>
+<DT>either RSA authentication</DT>
+<DD>standard in the FreeS/WAN distribution</DD>
+<DT>or X.509 certificates</DT>
+<DD>requires<A href="#PKIcert"> Super FreeS/WAN or a patch</A>.</DD>
+</DL>
+<P>In either case, each Road Warrior must have a different key or
+ certificate.</P>
+<P>It is also possible using pre-shared key authentication, though we
+ don't recommend this; see the<A href="#road.PSK"> next question</A> for
+ details.</P>
+<P>If you expect to have more than a few dozen Road Warriors connecting
+ simultaneously, you may need a fairly powerful gateway machine. See our
+ document on<A href="performance.html"> FreeS/WAN performance</A>.</P>
+<H3><A name="road.PSK">Can I have many road warriors using shared secret
+ authentication?</A></H3>
+<P><STRONG>Yes, but avoid it if possible</STRONG>.</P>
+<P>You can have multiple Road Warriors using shared secret
+ authentication<STRONG> only if they all use the same secret</STRONG>.
+ You must also set:</P>
+<P></P>
+<PRE>   uniqueids=no   </PRE>
+<P>in the connection definition.</P>
+<P>Why it's less secure:</P>
+<UL>
+<LI>If you have many users, it becomes almost certain the secret will
+ leak</LI>
+<LI>The secret becomes quite valuable to an attacker</LI>
+<LI>All users authenticate the same way, so the gateway cannot tell them
+ apart for logging or access control purposes</LI>
+<LI>Changing the secret is difficult. You have to securely notify all
+ users.</LI>
+<LI>If you find out the secret has been compromised, you can change it,
+ but then what? None of your users can connect without the new secret.
+ How will you notify them all, quickly and securely, without using the
+ VPN?</LI>
+</UL>
+<P>This is a designed-in limitation of the<A href="#IKE"> IKE</A> key
+ negotiation protocol, not a problem with our implementation.</P>
+<P><STRONG>We very strongly recommend that you avoid using shared secret
+ authentication for multiple Road Warriors.</STRONG> Use RSA
+ authentication instead.</P>
+<P>The longer story: When using shared secrets, the protocol requires
+ that the responding gateway be able to determine which secret to use at
+ a time when all it knows about the initiator is an IP address. This
+ works fine if you know the initiator's address in advance and can use
+ it to look up the appropiriate secret. However, it fails for Road
+ Warriors since the gateway cannot know their IP addresses in advance.</P>
+<P>With RSA signatures (or certificates) the protocol is slightly
+ different. The initiator provides an identifier early in the exchange
+ and the responder can use that identifier to look up the correct key or
+ certificate. See<A href="#road.many"> above</A>.</P>
+<H3><A name="QoS">Can I use Quality of Service routing with FreeS/WAN?</A>
+</H3>
+<P>From project technical lead Henry Spencer:</P>
+<PRE>&gt; Do QoS add to FreeS/WAN?
+&gt; For example integrating DiffServ and FreeS/WAN?
+
+With a current version of FreeS/WAN, you will have to add hidetos=no to
+the config-setup section of your configuration file.  By default, the TOS
+field of tunnel packets is zeroed; with hidetos=no, it is copied from the
+packet inside.  (This is a modest security hole, which is why it is no
+longer the default.)
+
+DiffServ does not interact well with tunneling in general.  Ways of
+improving this are being studied.</PRE>
+<P>Copying the<A href="#TOS"> TOS</A> (type of service) information from
+ the encapsulated packet to the outer header reveals the TOS information
+ to an eavesdropper. This does not tell him much, but it might be of use
+ in<A href="#traffic"> traffic analysis</A>. Since we do not have to
+ give it to him, our default is not to.</P>
+<P>Even with the TOS hidden, you can still:</P>
+<UL>
+<LI>apply QOS rules to the tunneled (ESP) packets; for example, by
+ giving ESP packets a certain priority.</LI>
+<LI>apply QOS rules to the packets as they enter or exit the tunnel via
+ an IPsec virtual interface (eg.<VAR> ipsec0</VAR>).</LI>
+</UL>
+<P>See<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf(5)</A> for more
+ on the<VAR> hidetos=</VAR> parameter.</P>
+<H3><A name="deadtunnel">Can I recognise dead tunnels and shut them
+ down?</A></H3>
+<P>There is no general mechanism to do this is in the IPsec protocols.</P>
+<P>From time to time, there is discussion on the IETF Working Group<A href="#ietf">
+ mailing list</A> of adding a &quot;keep-alive&quot; mechanism (which some say
+ should be called &quot;make-dead&quot;), but it is a fairly complex problem and
+ no consensus has been reached on whether or how it should be done.</P>
+<P>The protocol does have optional<A href="#ignore"> delete-SA</A>
+ messages which one side can send when it closes a connection in hopes
+ this will cause the other side to do the same. FreeS/WAN does not
+ currently support these. In any case, they would not solve the problem
+ since:</P>
+<UL>
+<LI>a gateway that crashes or hangs would not send the messages</LI>
+<LI>the sender is not required to send them</LI>
+<LI>they are not authenticated, so any receiver that trusts them leaves
+ itself open to a<A href="#DOS"> denial of service</A> attack</LI>
+<LI>the receiver is not required to do anything about them</LI>
+<LI>the receiver cannot acknowledge them; the protocol provides no
+ mechanism for that</LI>
+<LI>since they are not acknowledged, the sender cannot rely on them</LI>
+</UL>
+<P>However, connections do have limited lifetimes and you can control
+ how many attempts your gateway makes to rekey before giving up. For
+ example, you can set:</P>
+<PRE>conn default
+        keyingtries=3
+        keylife=30m</PRE>
+<P>With these settings old connections will be cleaned up. Within 30
+ minutes of the other end dying, rekeying will be attempted. If it
+ succeeds, the new connection replaces the old one. If it fails, no new
+ connection is created. Either way, the old connection is taken down
+ when its lifetime expires.</P>
+<P>Here is a mailing list message on the topic from FreeS/WAN tech
+ support person Claudia Schmeing:</P>
+<PRE>You ask how to determine whether a tunnel is redundant:
+
+&gt; Can anybody explain the best way to determine this. Esp when a RW has
+&gt; disconnected? I thought 'ipsec auto --status' might be one way.
+
+If a tunnel goes down from one end, Linux FreeS/WAN on the
+other end has no way of knowing this until it attempts to rekey.
+Once it tries to rekey and fails, it will 'know' that the tunnel is 
+down.
+
+Because it doesn't have a way of knowing the state until this point, 
+it will also not be able to tell you the state via ipsec auto --status.
+
+&gt; However, comparing output from a working tunnel with that of one that
+&gt; was closed 
+&gt; did not show clearly show tunnel status.
+
+If your tunnel is down but not 'unrouted' (see man ipsec_auto), you
+should not be able to ping the opposite side of the tunnel. You can
+use this as an indicator of tunnel status.
+
+On a related note, you may be interested to know that as of 1.7, 
+redundant tunnels caused by RW disconnections are likely to be 
+less of a pain. From doc/CHANGES:
+
+    There is a new configuration parameter, uniqueids, to control a new Pluto
+    option:  when a new connection is negotiated with the same ID as an old
+    one, the old one is deleted immediately.  This should help eliminate
+    dangling Road Warrior connections when the same Road Warrior reconnects. 
+    It thus requires that IDs not be shared by hosts (a previously legal but
+    probably useless capability).  NOTE WELL:  the sample ipsec.conf now has
+    uniqueids=yes in its config-setup section.
+
+
+Cheers,
+
+Claudia</PRE>
+<H3><A name="demanddial">Can I build IPsec tunnels over a demand-dialed
+ link?</A></H3>
+<P>This is possible, but not easy. FreeS/WAN technical lead Henry
+ Spencer wrote:</P>
+<PRE>&gt; 5. If the ISDN link goes down in between and is reestablished, the SAs
+&gt; are still up but the eroute are deleted and the IPsec interface shows
+&gt; garbage (with ifconfig)
+&gt; 6. Only restarting IPsec will bring the VPN back online.
+
+This one is awkward to solve.  If the real interface that the IPsec
+interface is mounted on goes down, it takes most of the IPsec machinery
+down with it, and a restart is the only good way to recover. 
+
+The only really clean fix, right now, is to split the machines in two: 
+
+1. A minimal machine serves as the network router, and only it is aware
+that the link goes up and down. 
+
+2. The IPsec is done on a separate gateway machine, which thinks it has
+a permanent network connection, via the router.
+
+This is clumsy but it does work.  Trying to do both functions within a
+single machine is tricky.  There is a software package (diald) which will
+give the illusion of a permanent connection for demand-dialed modem
+connections; I don't know whether it's usable for ISDN, or whether it can
+be made to cooperate properly with FreeS/WAN. 
+
+Doing a restart each time the interface comes up *does* work, although it
+is a bit painful.  I did that with PPP when I was running on a modem link;
+it wasn't hard to arrange the PPP scripts to bring IPsec up and down at
+the right times.  (I'd meant to investigate diald but never found time.)
+
+In principle you don't need to do a complete restart on reconnect, but you
+do have to rebuild some things, and we have no nice clean way of doing
+only the necessary parts.</PRE>
+<P>In the same thread, one user commented:</P>
+<PRE>Subject: Re: linux-ipsec: IPsec and Dial Up Connections
+   Date: Wed, 22 Nov 2000
+   From: Andy Bradford &lt;andyb@calderasystems.com&gt;
+
+On Wed, 22 Nov 2000 19:47:11 +0100, Philip Reetz wrote:
+
+&gt; Are there any ideas what might be the cause of the problem and any way
+&gt; to work around it.
+&gt; Any help is highly appreciated.
+
+On my laptop, when using ppp there is a ip-up script in /etc/ppp that 
+will be executed each time that the ppp interface is brought up.  
+Likewise there is an ip-down script that is called when it is taken 
+down.  You might consider custimzing those to stop and start FreeS/WAN 
+with each connection.  I believe that ISDN uses the same files, though 
+I could be wrong---there should be something similar though.</PRE>
+<H3><A name="GRE">Can I build GRE, L2TP or PPTP tunnels over IPsec?</A></H3>
+<P>Yes. Normally this is not necessary, but it is useful in a few
+ special cases. For example, if you must route non-IP packets such as
+ IPX, you will need to use a tunneling protocol that can route these
+ packets. IPsec can be layered around it for extra security. Another
+ example: you can provide failover protection for high availability (HA)
+ environments by combining IPsec with other tools. Ken Bantoft describes
+ one such setup in<A HREF="http://www.freeswan.ca/docs/HA"> Using
+ FreeS/WAN with Linux-HA, GRE, OSPF and BGP for enterprise grade VPN
+ solutions</A>.</P>
+<P>GRE over IPsec is covered as part of<A HREF="http://www.freeswan.ca/docs/HA">
+ that document</A>.<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/07/msg00209.html">
+ Here are links</A> to other GRE resources. Jacco de Leuw has created<A HREF="http://www.jacco2.dds.nl/networking/">
+ this page on L2TP over IPsec</A> with instructions for FreeS/WAN and
+ several other brands of IPsec software.</P>
+<P>Please let us know of other useful links via the<A HREF="mail.html">
+ mailing lists</A>.</P>
+<H3><A name="NetBIOS">... use Network Neighborhood (Samba, NetBIOS) over
+ IPsec?</A></H3>
+<P>Your local PC needs to know how to translate NetBIOS names to IP
+ addresses. It may do this either via a local LMHOSTS file, or using a
+ local or remote WINS server. The WINS server is preferable since it
+ provides a centralized source of the information to the entire network.
+ To use a WINS server over the<A HREF="#VPN"> VPN</A> (or any IP-based
+ network), you must enable &quot;NetBIOS over TCP&quot;.</P>
+<P><A HREF="http://www.samba.org">Samba</A> can emulate a WINS server on
+ Linux.</P>
+<P> See also several discussions in our<A HREF="http://lists.freeswan.org/pipermail/users/2002-September/thread.html">
+ September 2002 Users archives</A></P>
+<H2><A name="setup.faq">Life's little mysteries</A></H2>
+<P>FreeS/WAN is a fairly complex product. (Neither the networks it runs
+ on nor the protocols it uses are simple, so it could hardly be
+ otherwise.) It therefore sometimes exhibits behaviour which can be
+ somewhat confusing, or has problems which are not easy to diagnose.
+ This section tries to explain those problems.</P>
+<P>Setup and configuration of FreeS/WAN are covered in other
+ documentation sections:</P>
+<UL>
+<LI><A href="quickstart.html">basic setup and configuration</A></LI>
+<LI><A href="adv_config.html">advanced configuration</A></LI>
+<LI><A href="trouble.html">Troubleshooting</A></LI>
+</UL>
+<P>However, we also list some of the commonest problems here.</P>
+<H3><A name="cantping">I cannot ping ....</A></H3>
+<P>This question is dealt with in the advanced configuration section
+ under the heading<A href="#multitunnel"> multiple tunnels</A>.</P>
+<P>The standard subnet-to-subnet tunnel protects traffic<STRONG> only
+ between the subnets</STRONG>. To test it, you must use pings that go
+ from one subnet to the other.</P>
+<P>For example, suppose you have:</P>
+<PRE>      subnet a.b.c.0/24
+             |
+      eth1 = a.b.c.1
+         gate1
+      eth0 = 192.0.2.8
+             |
+
+       ~ internet ~
+
+             |
+      eth0 = 192.0.2.11
+         gate2
+      eth1 = x.y.z.1
+              |
+       subnet x.y.z.0/24</PRE>
+<P>and the connection description:</P>
+<PRE>conn abc-xyz
+     left=192.0.2.8
+     leftsubnet=a.b.c.0/24
+     right=192.0.2.11
+     rightsubnet=x.y.z.0/24</PRE>
+<P>You can test this connection description only by sending a ping that
+ will actually go through the tunnel. Assuming you have machines at
+ addresses a.b.c.2 and x.y.z.2, pings you might consider trying are:</P>
+<DL>
+<DT>ping from x.y.z.2 to a.b.c.2 or vice versa</DT>
+<DD>Succeeds if tunnel is working. This is the<STRONG> only valid test
+ of the tunnel</STRONG>.</DD>
+<DT>ping from gate2 to a.b.c.2 or vice versa</DT>
+<DD><STRONG>Does not use tunnel</STRONG>. gate2 is not on protected
+ subnet.</DD>
+<DT>ping from gate1 to x.y.z.2 or vice versa</DT>
+<DD><STRONG>Does not use tunnel</STRONG>. gate1 is not on protected
+ subnet.</DD>
+<DT>ping from gate1 to gate2 or vice versa</DT>
+<DD><STRONG>Does not use tunnel</STRONG>. Neither gate is on a protected
+ subnet.</DD>
+</DL>
+<P>Only the first of these is a useful test of this tunnel. The others
+ do not use the tunnel. Depending on other details of your setup and
+ routing, they:</P>
+<UL>
+<LI>either fail, telling you nothing about the tunnel</LI>
+<LI>or succeed, telling you nothing about the tunnel since these packets
+ use some other route</LI>
+</UL>
+<P>In some cases, you may be able to get around this. For the example
+ network above, you could use:</P>
+<PRE>        ping -I a.b.c.1 x.y.z.1</PRE>
+<P>Both the adresses given are within protected subnets, so this should
+ go through the tunnel.</P>
+<P>If required, you can build additional tunnels so that all the
+ machines involved can talk to all the others. See<A href="#multitunnel">
+ multiple tunnels</A> in the advanced configuration document for
+ details.</P>
+<H3><A name="forever">It takes forever to ...</A></H3>
+<P>Users fairly often report various problems involving long delays,
+ sometimes on tunnel setup and sometimes on operations done through the
+ tunnel, occasionally on simple things like ping or more often on more
+ complex operations like doing NFS or Samba through the tunnel.</P>
+<P>Almost always, these turn out to involve failure of a DNS lookup. The
+ timeouts waiting for DNS are typically set long so that you won't time
+ out when a query involves multiple lookups or long paths. Genuine
+ failures therefore produce long delays before they are detected.</P>
+<P>A mailing list message from project technical lead Henry Spencer:</P>
+<PRE>&gt; ... when i run /etc/rc.d/init.d/ipsec start, i get:
+&gt; ipsec_setup: Starting FreeS/WAN IPsec 1.5...
+&gt; and it just sits there, doesn't give back my bash prompt.
+
+Almost certainly, the problem is that you're using DNS names in your
+ipsec.conf, but DNS lookups are not working for some reason.  You will
+get your prompt back... eventually.  But the DNS timeouts are long.
+Doing something about this is on our list, but it is not easy.</PRE>
+<P>In the meanwhile, we recommend that connection descriptions in<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A> use numeric IP addresses rather than names which will
+ require a DNS lookup.</P>
+<P>Names that do not require a lookup are fine. For example:</P>
+<UL>
+<LI>a road warrior might use the identity<VAR>
+ rightid=@lancelot.example.org</VAR></LI>
+<LI>the gateway might use<VAR> leftid=@camelot.example.org</VAR></LI>
+</UL>
+<P>These are fine. The @ sign prevents any DNS lookup. However, do not
+ attempt to give the gateway address as<VAR> left=camelot.example.org</VAR>
+. That requires a lookup.</P>
+<P>A post from one user after solving a problem with long delays:</P>
+<PRE>Subject: Final Answer to Delay!!!
+   Date: Mon, 19 Feb 2001
+   From: &quot;Felippe Solutions&quot; &lt;felippe@solutionstecnologia.com.br&gt;
+
+Sorry people, but seems like the Delay problem had nothing to do with
+freeswan.
+
+The problem was DNS as some people sad from the beginning, but not the way
+they thought it was happening. Samba, ssh, telnet and other apps try to
+reverse lookup addresses when you use IP numbers (Stupid that ahh).
+
+I could ping very fast because I always ping with &quot;-n&quot; option, but I don't
+know the option on the other apps to stop reverse addressing so I don't use
+it.</PRE>
+<P>This post is fairly typical. These problems are often tricky and
+ frustrating to diagnose, and most turn out to be DNS-related.</P>
+<P>One suggestion for diagnosis: test with both names and addresses if
+ possible. For example, try all of:</P>
+<UL>
+<LI>ping<VAR> address</VAR></LI>
+<LI>ping -n<VAR> address</VAR></LI>
+<LI>ping<VAR> name</VAR></LI>
+</UL>
+<P>If these behave differently, the problem must be DNS-related since
+ the three commands do exactly the same thing except for DNS lookups.</P>
+<H3><A name="route">I send packets to the tunnel with route(8) but they
+ vanish</A></H3>
+<P>IPsec connections are designed to carry only packets travelling
+ between pre-defined connection endpoints. As project technical lead
+ Henry Spencer put it:</P>
+<BLOCKQUOTE> IPsec tunnels are not just virtual wires; they are virtual
+ wires with built-in access controls. Negotiation of an IPsec tunnel
+ includes negotiation of access rights for it, which don't include
+ packets to/from other IP addresses. (The protocols themselves are quite
+ inflexible about this, so there are limits to what we can do about it.)</BLOCKQUOTE>
+<P>For fairly obvious security reasons, and to comply with the IPsec
+ RFCs,<A href="#KLIPS"> KLIPS</A> drops any packets it receives that are
+ not allowed on the tunnels currently defined. So if you send it packets
+ with<VAR> route(8)</VAR>, and suitable tunnels are not defined, the
+ packets vanish. Whether this is reported in the logs depends on the
+ setting of<VAR> klipsdebug</VAR> in your<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A> file.</P>
+<P>To rescue vanishing packets, you must ensure that suitable tunnels
+ for them exist, by editing the connection descriptions in<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A>. For example, supposing you have a simple setup:</P>
+<PRE>         leftsubnet -- leftgateway === internet === roadwarrior</PRE>
+<P>If you want to give the roadwarrior access to some resource that is
+ located behind the left gateway but is not in the currently defined
+ left subnet, then the usual procedure is to define an additional tunnel
+ for those packets by creating a new connection description.</P>
+<P>In some cases, it may be easier to alter an existing connection
+ description, enlarging the definition of<VAR> leftsubnet</VAR>. For
+ example, instead of two connection descriptions with 192.168.8.0/24 and
+ 192.168.9.0/24 as their<VAR> leftsubnet</VAR> parameters, you can use a
+ single description with 192.168.8.0/23.</P>
+<P>If you have multiple endpoints on each side, you need to ensure that
+ there is a route for each pair of endpoints. See this<A href="#multitunnel">
+ example</A>.</P>
+<H3><A name="down_route">When a tunnel goes down, packets vanish</A></H3>
+<P>This is a special case of the vanishing packet problem described in
+ the previous question. Whenever KLIPS sees packets for which it does
+ not have a tunnel, it drops them.</P>
+<P>When a tunnel goes away, either because negotiations with the other
+ gateway failed or because you gave an<VAR> ipsec auto --down</VAR>
+ command, the route to its other end is left pointing into KLIPS, and
+ KLIPS will drop packets it has no tunnel for.</P>
+<P>This is a documented design decision, not a bug. FreeS/WAN must not
+ automatically adjust things to send packets via another route. The
+ other route might be insecure.</P>
+<P>Of course, re-routing may be necessary in many cases. In those cases,
+ you have to do it manually or via scripts. We provide the<VAR> ipsec
+ auto --unroute</VAR> command for these cases.</P>
+<P>From<A href="manpage.d/ipsec_auto.8.html"> ipsec_auto(8)</A>:</P>
+<BLOCKQUOTE> Normally, pluto establishes a route to the destination
+ specified for a connection as part of the --up operation. However, the
+ route and only the route can be established with the --route operation.
+ Until and unless an actual connection is established, this discards any
+ packets sent there, which may be preferable to having them sent
+ elsewhere based on a more general route (e.g., a default route).</BLOCKQUOTE><BLOCKQUOTE>
+ Normally, pluto's route to a destination remains in place when a --down
+ operation is used to take the connection down (or if connection setup,
+ or later automatic rekeying, fails). This permits establishing a new
+ connection (perhaps using a different specification; the route is
+ altered as necessary) without having a ``window'' in which packets
+ might go elsewhere based on a more general route. Such a route can be
+ removed using the --unroute operation (and is implicitly removed by
+ --delete).</BLOCKQUOTE>
+<P>See also this mailing list<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/11/msg00523.html">
+ message</A>.</P>
+<H3><A name="firewall_ate">The firewall ate my packets!</A></H3>
+<P>If firewalls filter out:</P>
+<UL>
+<LI>either the UDP port 500 packets used in IKE negotiations</LI>
+<LI>or the ESP and AH (protocols 50 and 51) packets used to implement
+ the IPsec tunnel</LI>
+</UL>
+<P>then IPsec cannot work. The first thing to check if packets seem to
+ be vanishing is the firewall rules on the two gateway machines and any
+ other machines along the path that you have access to.</P>
+<P>For details, see our document on<A href="firewall.html"> firewalls</A>
+.</P>
+<P>Some advice from technical lead Henry Spencer on diagnosing such
+ problems:</P>
+<PRE>&gt; &gt; Packets vanishing between the hardware interface and the ipsecN interface
+&gt; &gt; is usually the result of firewalls not being configured to let them in...
+&gt; 
+&gt; Thanks for the suggestion. If only it were that simple! My ipchains startup
+&gt; script does take care of that, but just in case I manually inserted rules 
+&gt; accepting everything from london on dublin. No difference.
+
+The other thing to check is whether the &quot;RX packets dropped&quot; count on the
+ipsecN interface (run &quot;ifconfig ipsecN&quot;, for N=1 or whatever, to see the
+counts) is rising.  If so, then there's some sort of configuration mismatch
+between the two ends, and IPsec itself is rejecting them.  If none of the
+ipsecN counts is rising, then the packets are never reaching the IPsec
+machinery, and the problem is almost certainly in firewalls etc.</PRE>
+<H3><A name="dropconn">Dropped connections</A></H3>
+<P>Networks being what they are, IPsec connections can be broken for any
+ number of reasons, ranging from hardware failures to various software
+ problems such as the path MTU problems discussed<A href="#pmtu.broken">
+ elsewhere in the FAQ</A>. Fortunately, various diagnostic tools exist
+ that help you sort out many of the possible problems.</P>
+<P>There is one situation, however, where FreeS/WAN (using default
+ settings) may destroy a connection for no readily apparent reason. This
+ occurs when things are<STRONG> misconfigured</STRONG> so that<STRONG>
+ two tunnels</STRONG> from the same gateway expect<STRONG> the same
+ subnet on the far end</STRONG>.</P>
+<P>In this situation, the first tunnel comes up fine and works until the
+ second is established. At that point, because of the way we track
+ connections internally, the first tunnel ceases to exist as far as this
+ gateway is concerned. Of course the far end does not know that, and a
+ storm of error messages appears on both systems as it tries to use the
+ tunnel.</P>
+<P>If the far end gives up, goes back to square one and negotiates a new
+ tunnel, then that wipes out the second tunnel and ...</P>
+<P>The solution is simple.<STRONG> Do not build multiple conn
+ descriptions with the same remote subnet</STRONG>.</P>
+<P>This is actually intended to be a feature, rather than a bug.
+ Consider the situation where a single remote system goes down, then
+ comes back up and reconnects to the gateway. It is useful to have the
+ gateway tear down the old tunnel and recover resources when the
+ reconnection is made. It recognises that situation by checking the
+ remote subnet for each tunnel it builds and discarding duplicates. This
+ works fine as long as you don't configure multiple tunnels with the
+ same remote subnet.</P>
+<P>If this behaviour is inconvenient for you, you can disable it by
+ setting<VAR> uniqueids=no</VAR> in<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A>.</P>
+<H3><A name="defaultroutegone">Disappearing %defaultroute</A></H3>
+<P>When an underlying connection (eg. ppp) goes down, FreeS/WAN will not
+ recover properly without a little help. Here are the symptoms that
+ FreeS/WAN user Michael Carmody noticed:</P>
+<PRE>
+&gt; After about 24 hours the freeswan connection takes over the default route.
+&gt; 
+&gt; i.e instead of deafult gateway pointing to the router via eth0, it becomes a 
+&gt; pointer to the router via ipsec0.
+ 
+&gt; All internet access is then lost as all replies (and not just the link I 
+&gt; wanted) are routed out ipsec0 and the router doesn't respond to the ipsec 
+&gt; traffic.
+</PRE>
+<P>If you're using a FreeS/WAN 2.x/KLIPS system, simply re-attach the
+ IPsec virtual interface with<EM> ipsec tnconfig</EM> command such as:</P>
+<PRE>    ipsec tnconfig --attach --virtual ipsec0 --physical ppp0</PRE>
+<P>In your command, name the physical and virtual interfaces as they
+ appear paired on your system during regular uptime. For a system with
+ several physical/virtual interface pairs on flaky links, you'll need
+ more than one such command. If you're using FreeS/WAN 1.x, you must
+ restart FreeS/WAN, which is more time consuming.</P>
+<P><A href="http://lists.freeswan.org/pipermail/design/2002-July/003070.html">
+ Here</A> is a script which can help to automate the process of
+ FreeS/WAN restart at need. It could easily be adapted to use tnconfig
+ instead.</P>
+<H3><A name="tcpdump.faq">TCPdump on the gateway shows strange things</A>
+</H3>
+ As another user pointed out, keeping the connect
+<P>Attempting to look at IPsec packets by running monitoring tools on
+ the IPsec gateway machine can produce silly results. That machine is
+ mangling the packets for IPsec, and possibly for firewall or NAT
+ purposes as well. If the internals of the machine's IP stack are not
+ what the monitoring tool expects, then the tool can misinterpret them
+ and produce nonsense output.</P>
+<P>See our<A href="#tcpdump.test"> testing</A> document for more detail.</P>
+<H3><A name="no_trace">Traceroute does not show anything between the
+ gateways</A></H3>
+<P>As far as traceroute can see, the two gateways are one hop apart; the
+ data packet goes directly from one to the other through the tunnel. Of
+ course the outer packets that implement the tunnel pass through
+ whatever lies between the gateways, but those packets are built and
+ dismantled by the gateways. Traceroute does not see them and cannot
+ report anything about their path.</P>
+<P>Here is a mailing list message with more detail.</P>
+<PRE>Date: Mon, 14 May 2001
+To: linux-ipsec@freeswan.org
+From: &quot;John S. Denker&quot; &lt;jsd@research.att.com&lt;
+Subject: Re: traceroute: one virtual hop
+
+At 02:20 PM 5/14/01 -0400, Claudia Schmeing wrote:
+&gt;
+&gt;&gt; &gt; A bonus question: traceroute in subnet to subnet enviroment looks like:
+&gt;&gt; &gt; 
+&gt;&gt; &gt; traceroute to andris.dmz (172.20.24.10), 30 hops max, 38 byte packets
+&gt;&gt; &gt; 1  drama (172.20.1.1)  0.716 ms  0.942 ms  0.434 ms
+&gt;&gt; &gt; 2  * * *
+&gt;&gt; &gt; 3  andris.dmz (172.20.24.10)  73.576 ms  78.858 ms  79.434 ms
+&gt;&gt; &gt; 
+&gt;&gt; &gt; Why aren't there the other hosts which take part in the delivery during 
+&gt;    * * * ?
+&gt;
+&gt;If there is an ipsec tunnel between GateA and Gate B, this tunnel forms a 
+&gt;'virtual wire'.  When it is tunneled, the original packet becomes an inner 
+&gt;packet, and new ESP and/or AH headers are added to create an outer packet 
+&gt;around it. You can see an example of how this is done for AH at 
+&gt;doc/ipsec.html#AH . For ESP it is similar.
+&gt;
+&gt;Think about the packet's path from the inner packet's perspective.
+&gt;It leaves the subnet, goes into the tunnel, and re-emerges in the second
+&gt;subnet. This perspective is also the only one available to the
+&gt;'traceroute' command when the IPSec tunnel is up.
+
+Claudia got this exactly right.  Let me just expand on a couple of points:
+
+*) GateB is exactly one (virtual) hop away from GateA.  This is how it
+would be if there were a physically private wire from A to B.  The
+virtually private connection should work the same, and it does.
+
+*) While the information is in transit from GateA to GateB, the hop count
+of the outer header (the &quot;envelope&quot;) is being decremented.  The hop count
+of the inner header (the &quot;contents&quot; of the envelope) is not decremented and
+should not be decremented.  The hop count of the outer header is not
+derived from and should not be derived from the hop count of the inner header.
+
+Indeed, even if the packets did time out in transit along the tunnel, there
+would be no way for traceroute to find out what happened.  Just as
+information cannot leak _out_ of the tunnel to the outside, information
+cannot leak _into_ the tunnel from outside, and this includes ICMP messages
+from routers along the path.
+
+There are some cases where one might wish for information about what is
+happening at the IP layer (below the tunnel layer) -- but the protocol
+makes no provision for this.  This raises all sorts of conceptual issues.
+AFAIK nobody has ever cared enough to really figure out what _should_
+happen, let alone implement it and standardize it.
+
+*) I consider the &quot;* * *&quot; to be a slight bug.  One might wish for it to be
+replaced by &quot;GateB GateB GateB&quot;.  It has to do with treating host-to-subnet
+traffic different from subnet-to-subnet traffic (and other gory details).
+I fervently hope KLIPS2 will make this problem go away.
+
+*) If you want to ask questions about the link from GateA to GateB at the
+IP level (below the tunnel level), you have to ssh to GateA and launch a
+traceroute from there.</PRE>
+<H2><A name="man4debug">Testing in stages</A></H2>
+<P>It is often useful in debugging to test things one at a time:</P>
+<UL>
+<LI>disable IPsec entirely, for example by turning it off with
+ chkconfig(8), and make sure routing works</LI>
+<LI>Once that works, try a manually keyed connection. This does not
+ require key negotiation between Pluto and the key daemon on the other
+ end.</LI>
+<LI>Once that works, try automatically keyed connections</LI>
+<LI>Once IPsec works, add packet compression</LI>
+<LI>Once everything seems to work, try stress tests with large
+ transfers, many connections, frequent re-keying, ...</LI>
+</UL>
+<P>FreeS/WAN releases are tested for all of these, so you can be
+ reasonably certain they<EM> can</EM> do them all. Of course, that does
+ not mean they<EM> will</EM> on the first try, especially if you have
+ some unusual configuration.</P>
+<P>The rest of this section gives information on diagnosing the problem
+ when each of the above steps fails.</P>
+<H3><A name="nomanual">Manually keyed connections don't work</A></H3>
+<P>Suspect one of:</P>
+<UL>
+<LI>mis-configuration of IPsec system in the /etc/ipsec.conf file
+<BR> common errors are incorrect interface or next hop information</LI>
+<LI>mis-configuration of manual connection in the /etc/ipsec.conf file</LI>
+<LI>routing problems causing IPsec packets to be lost</LI>
+<LI>bugs in KLIPS</LI>
+<LI>mismatch between the transforms we support and those another IPsec
+ implementation offers.</LI>
+</UL>
+<H3><A name="spi_error">One manual connection works, but second one
+ fails</A></H3>
+<P>This is a fairly common problem when attempting to configure multiple
+ manually keyed connections from a single gateway.</P>
+<P>Each connection must be identified by a unique<A href="#SPI"> SPI</A>
+ value. For automatic connections, these values are assigned
+ automatically. For manual connections, you must set them with<VAR> spi=</VAR>
+ statements in<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf(5)</A>.</P>
+<P>Each manual connection must have a unique SPI value in the range
+ 0x100 to 0x999. Two or more with the same value will fail. For details,
+ see our doc section<A href="#prodman"> Using manual keying in
+ production</A> and the man page<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A>.</P>
+<H3><A name="man_no_auto">Manual connections work, but automatic keying
+ doesn't</A></H3>
+<P>The most common reason for this behaviour is a firewall dropping the
+ UDP port 500 packets used in key negotiation.</P>
+<P>Other possibilities:</P>
+<UL>
+<LI>mis-configuration of auto connection in the /etc/ipsec.conf file.
+<P>One common configuration error is forgetting that you need<VAR>
+ auto=add</VAR> to load the connection description on the receiving end
+ so it recognises the connection when the other end asks for it.</P>
+</LI>
+<LI>error in shared secret in /etc/ipsec.secrets</LI>
+<LI>one gateway lacks a route to the other so Pluto's UDP packets are
+ lost</LI>
+<LI>bugs in Pluto</LI>
+<LI>incompatibilities between Pluto's<A href="#IKE"> IKE</A>
+ implementation and the IKE at the other end of the tunnel.
+<P>Some possibile problems are discussed in out<A href="interop.html#interop.problem">
+ interoperation</A> document.</P>
+</LI>
+</UL>
+<H3><A name="nocomp">IPsec works, but connections using compression fail</A>
+</H3>
+<P>When we first added compression, we saw some problems:</P>
+<UL>
+<LI>compatibility issues with other implementations. We followed the
+ RFCs and omitted some extra material that many compression libraries
+ add by default. Some other implementations left the extras in</LI>
+<LI>bugs in assembler compression routines on non-Intel CPUs. The
+ workaround is to use C code instead of possibly problematic assembler.</LI>
+</UL>
+<P>We have not seen either problem in some time (at least six months as
+ I write in March 2002), but if you have some unusual configuration then
+ you may see them.</P>
+<H3><A name="pmtu.broken">Small packets work, but large transfers fail</A>
+</H3>
+<P>If tests with ping(1) and a small packet size succeed, but tests or
+ transfers with larger packet sizes fail, suspect problems with packet
+ fragmentation and perhaps<A href="#pathMTU"> path MTU discovery</A>.</P>
+<P>Our<A href="#bigpacket"> troubleshooting document</A> covers these
+ problems. Information on the underlying mechanism is in our<A href="#MTU.trouble">
+ background</A> document.</P>
+<H3><A name="subsub">Subnet-to-subnet works, but tests from the gateways
+ don't</A></H3>
+<P>This is described under<A href="#cantping"> I cannot ping...</A>
+ above.</P>
+<H2><A name="compile.faq">Compilation problems</A></H2>
+<H3><A name="gmp.h_missing">gmp.h: No such file or directory</A></H3>
+<P>Pluto needs the GMP (<STRONG>G</STRONG>NU</P>
+<P><STRONG>M</STRONG>ulti-<STRONG>P</STRONG>recision) library for the
+ large integer calculations it uses in<A href="#public"> public key</A>
+ cryptography. This error message indicates a failure to find the
+ library. You must install it before Pluto will compile.</P>
+<P>The GMP library is included in most Linux distributions. Typically,
+ there are two RPMs, libgmp and libgmp-devel, You need to<EM> install
+ both</EM>, either from your distribution CDs or from your vendor's web
+ site.</P>
+<P>On Debian, a mailing list message reports that the command to give is<VAR>
+ apt-get install gmp2</VAR>.</P>
+<P>For more information and the latest version, see the<A href="http://www.swox.com/gmp/">
+ GMP home page</A>.</P>
+<H3><A name="noVM">... virtual memory exhausted</A></H3>
+<P>We have had several reports of this message appearing, all on SPARC
+ Linux. Here is a mailing message on a solution:</P>
+<PRE>&gt; ipsec_sha1.c: In function `SHA1Transform':
+&gt; ipsec_sha1.c:95: virtual memory exhausted
+
+I'm seeing exactly the same problem on an Ultra with 256MB ram and 500
+MB swap.  Except I am compiling version 1.5 and its Red Hat 6.2.
+
+I can get around this by using -O instead of -O2 for the optimization
+level.  So it is probably a bug in the optimizer on the sparc complier. 
+I'll try and chase this down on the sparc lists.</PRE>
+<H2><A name="error">Interpreting error messages</A></H2>
+<H3><A name="route-client">route-client (or host) exited with status 7</A>
+</H3>
+<P>Here is a discussion of this error from FreeS/WAN &quot;listress&quot; (mailing
+ list tech support person) Claudia Schmeing. The &quot;FAQ on the network
+ unreachable error&quot; which she refers to is the next question below.</P>
+<PRE>&gt; I reached the point where the two boxes (both on dial-up connections, but
+&gt; treated as static IPs by getting the IP and editing ipsec.conf after the
+&gt; connection is established) to the point where they exchange some info, but I
+&gt; get an error like &quot;route-client command exited with status 7 \n internal
+&gt; error&quot;.
+&gt; Where can I find a description of this error?
+
+In general, if the FAQ doesn't cover it, you can search the mailing list 
+archives - I like to use
+http://www.sandelman.ottawa.on.ca/linux-ipsec/
+but you can see doc/mail.html for different archive formats.
+
+
+Your error comes from the _updown script, which performs some
+routing and firewall functions to help Linux FreeS/WAN. More info
+is available at doc/firewall.html and man ipsec.conf. Its routing
+is integral to the health of Linux FreeS/WAN; it also provides facility
+to insert custom firewall rules to be executed when you create or destroy
+a connection.
+
+Yours is, of course, a routing error. You can be fairly sure the routing 
+machinery is saying &quot;network is unreachable&quot;. There's a FAQ on the 
+&quot;network is unreachable&quot; error, but more information is available now; read on.
+
+If your _updown script is recent (for example if it shipped with 
+Linux FreeS/WAN 1.91), you will see another debugging line in your logs 
+that looks something like this:
+
+&gt; output: /usr/local/lib/ipsec/_updown: `route add -net 128.174.253.83 
+&gt; netmask 255.255.255.255 dev ipsec0 gw 66.92.93.161' failed
+
+This is, of course, the system route command that exited with status 7, 
+(ie. failed). Man route for details. Seeing the command typed out yields 
+more information. If your _updown script is older, you may wish to update 
+it to show the command explicitly.
+
+Three parameters fed to the route command: net, netmask and gw [gateway] 
+are derived from things you've put in ipsec.conf.
+
+Net and netmask are derived from the peer's IP and mask. In more detail:
+
+You may see a routing error when routing to a client (ie. subnet), or 
+to a host (IPSec gateway or freestanding host; a box that does IPSec for
+itself). In _updown, the &quot;route-client&quot; section  is responsible to set up 
+the route for IPSec'd (usually, read 'tunneled') packets headed to a 
+peer subnet. Similarly, route-host routes IPSec'd packets to a peer host
+or IPSec gateway.
+
+When routing to a 'client', net and netmask are ipsec.conf's left- or 
+rightsubnet (whichever is not local). Similarly, when routing to a 
+'host' the net is left or right. Host netmask is always /32, indicating a 
+single machine.
+
+Gw is nexthop's value. Again, the value in question is left- or rightnexthop,
+whichever is local. Where left/right or left-/rightnexthop has the special 
+value %defaultroute (described in man ipsec.conf), gw will automagically get
+the value of the next hop on the default route.
+
+Q: &quot;What's a nexthop and why do I need one?&quot;
+
+A: 'nexthop' is a routing kluge; its value is the next hop away
+   from the machine that's doing IPSec, and toward your IPSec peer. 
+   You need it to get the processed packets out of the local system and 
+   onto the wire. While we often route other packets through the machine 
+   that's now doing IPSec, and are done with it, this does not suffice here. 
+   After packets are processed with IPSec, this machine needs to know where 
+   they go next. Of course using the 'IPSec gateway' as their routing gateway 
+   would cause an infinite loop! [To visualize this, see the packet flow 
+   diagram at doc/firewall.html.] To avoid this, we route packets through 
+   the next hop down their projected path.
+
+Now that you know the background, consider:
+1. Did you test routing between the gateways in the absence of Linux
+   FreeS/WAN, as recommended? You need to ensure the two machines that
+   will be running Linux FreeS/WAN can route to one another before trying to 
+   make a secure connection.
+2. Is there anything obviously wrong with the sense of your route command?
+
+Normally, this problem is caused by an incorrect local nexthop parameter.
+Check out the use of %defaultroute, described in man ipsec.conf. This is
+a simple way to set nexthop for most people. To figure nexthop out by hand,
+traceroute in-the-clear to your IPSec peer. Nexthop is the traceroute's 
+first hop after your IPSec gateway.</PRE>
+<H3><A name="unreachable">SIOCADDRT:Network is unreachable</A></H3>
+<P>This message is not from FreeS/WAN, but from the Linux IP stack
+ itself. That stack is seeing packets it has no route for, either
+ because your routing was broken before FreeS/WAN started or because
+ FreeS/WAN's changes broke it.</P>
+<P>Here is a message from Claudia suggesting ways to diagnose and fix
+ such problems:</P>
+<PRE>You write,
+&gt; I have correctly installed freeswan-1.8 on RH7.0 kernel 2.2.17, but when 
+&gt; I setup a VPN connection with the other machine(RH5.2 Kernel 2.0.36 
+&gt; freeswan-1.0, it works well.) it told me that 
+&gt; &quot;SIOCADDRT:Network is unreachable&quot;!  But the network connection is no 
+&gt; problem.
+
+Often this error is the result of a misconfiguration. 
+
+Be sure that you can route successfully in the absence of Linux
+FreeS/WAN. (You say this is no problem, so proceed to the next step.)
+
+Use a custom copy of the default updownscript. Do not change the route 
+commands, but add a diagnostic message revealing the exact text of the 
+route command. Is there a problem with the sense of the route command
+that you can see? If so, then re-examine those ipsec.conf settings
+that are being sent to the route command. 
+
+You may wish to use the ipsec auto --route and --unroute commands to 
+troubleshoot the problem. See man ipsec_auto for details.</PRE>
+<P>Since the above message was written, we have modified the updown
+ script to provide a better diagnostic for this problem. Check<VAR>
+ /var/log/messages</VAR>.</P>
+<P>See also the FAQ question<A href="#route-client"> route-client (or
+ host) exited with status 7</A>.</P>
+<H3><A name="modprobe">ipsec_setup: modprobe: Can't locate module ipsec</A>
+</H3>
+<H3><A name="noKLIPS">ipsec_setup: Fatal error, kernel appears to lack
+ KLIPS</A></H3>
+<P>These messages indicate an installation failure. The kernel you are
+ running does not contain the<A href="#KLIPS"> KLIPS (kernel IPsec)</A>
+ code.</P>
+<P>Note that the &quot;modprobe: Can't locate module ipsec&quot; message appears
+ even if you are not using modules. If there is no KLIPS in your kernel,
+ FreeS/WAN tries to load it as a module. If that fails, you get this
+ message.</P>
+<P>Commands you can quickly try are:</P>
+<DL>
+<DT><VAR>uname -a</VAR></DT>
+<DD>to get details, including compilation date and time, of the
+ currently running kernel</DD>
+<DT><VAR>ls /</VAR></DT>
+<DT><VAR>ls /boot</VAR></DT>
+<DD>to ensure a new kernel is where it should be. If kernel compilation
+ puts it in<VAR> /</VAR> but<VAR> lilo</VAR> wants it in<VAR> /boot</VAR>
+, then you should uncomment the<VAR> INSTALL_PATH=/boot</VAR> line in
+ the kernel<VAR> Makefile</VAR>.</DD>
+<DT><VAR>more /etc/lilo.conf</VAR></DT>
+<DD>to see that<VAR> lilo</VAR> has correct information</DD>
+<DT><VAR>lilo</VAR></DT>
+<DD>to ensure that information in<VAR> /etc/lilo.conf</VAR> has been
+ transferred to the boot sector</DD>
+</DL>
+<P>If those don't find the problem, you have to go back and check
+ through the<A href="install.html"> install</A> procedure to see what
+ was missed.</P>
+<P>Here is one of Claudia's messages on the topic:</P>
+<PRE>&gt; I tried to install freeswan 1.8 on my mandrake 7.2 test box. ...
+
+&gt; It does show version and some output for whack.
+
+Yes, because the Pluto (daemon) part of ipsec is installed correctly, but
+as we see below the kernel portion is not.
+
+&gt; However, I get the following from /var/log/messages:
+&gt; 
+&gt; Mar 11 22:11:55 pavillion ipsec_setup: Starting FreeS/WAN IPsec 1.8...
+&gt; Mar 11 22:12:02 pavillion ipsec_setup: modprobe: Can't locate module ipsec
+&gt; Mar 11 22:12:02 pavillion ipsec_setup: Fatal error, kernel appears to lack
+&gt; KLIPS.
+
+This is your problem. You have not successfully installed a kernel with
+IPSec machinery in it. 
+
+Did you build Linux FreeS/WAN as a module? If so, you need to ensure that 
+your new module has been installed in the directory where your kernel 
+loader normally finds your modules. If not, you need to ensure
+that the new IPSec-enabled kernel is being loaded correctly.
+
+See also doc/install.html, and INSTALL in the distro.</PRE>
+<H3><A name="noDNS">ipsec_setup: ... failure to fetch key for ... from
+ DNS</A></H3>
+<P>Quoting Henry:</P>
+<PRE>Note that by default, FreeS/WAN is now set up to
+     (a) authenticate with RSA keys, and
+     (b) fetch the public key of the far end from DNS.
+Explicit attention to  ipsec.conf will be needed if you want
+to do something different.</PRE>
+<P>and Claudia, responding to the same user:</P>
+<PRE>You write,
+
+&gt;       My current setup in ipsec.conf is leftrsasigkey=%dns I have 
+&gt; commented this and authby=rsasig out. I am able to get ipsec running, 
+&gt; but what I find is that the documentation only specifies for %dns are 
+&gt; there any other values that can be placed in this variable other than 
+&gt; %dns and the key? I am also assuming that this is where I would place 
+&gt; my public key for the left and right side as well is this correct?
+
+Valid values for authby= are rsasig and secret, which entail authentication
+by RSA signature or by shared secret, respectively. Because you have 
+commented authby=rsasig out, you are using the default value of authby=secret. 
+
+When using RSA signatures, there are two ways to get the public key for the
+IPSec peer: either copy it directly into *rsasigkey= in ipsec.conf, or
+fetch it from dns. The magic value %dns for *rsasigkey parameters says to 
+try to fetch the peer's key from dns.
+
+For any parameters, you may find their significance and special values in
+man ipsec.conf. If you are setting up keys or secrets, be sure also to
+reference man ipsec.secrets.</PRE>
+<H3><A name="dup_address">ipsec_setup: ... interfaces ... and ... share
+ address ...</A></H3>
+<P>This is a fatal error. FreeS/WAN cannot cope with two or more
+ interfaces using the same IP address. You must re-configure to avoid
+ this.</P>
+<P>A mailing list message on the topic from Pluto developer Hugh
+ Redelmeier:</P>
+<PRE>| I'm trying to get freeswan working between two machine where one has a ppp
+| interface.
+| I've already suceeded with  two machines with ethernet ports but  the ppp
+| interface is causing me problems.
+|  basically when I run ipsec start  i get
+| ipsec_setup: Starting FreeS/WAN IPsec 1.7...
+| ipsec_setup: 003 IP interfaces ppp1 and ppp0 share address 192.168.0.10!
+| ipsec_setup: 003 IP interfaces ppp1 and ppp2 share address 192.168.0.10!
+| ipsec_setup: 003 IP interfaces ppp0 and ppp2 share address 192.168.0.10!
+| ipsec_setup: 003 no public interfaces found
+|
+| followed by lots of cannot work out interface for connection messages
+|
+| now I can specify the interface in ipsec.conf to be ppp0 , but this does
+| not affect the above behaviour. A quick look in server.c indicates that the
+| interfaces value  is not used but some sort of raw detect happens.
+|
+| I guess I could prevent the formation of the extra ppp interfaces or
+| allocate them different ip but I'd  rather not. if at all possible. Any
+| suggestions please.
+
+Pluto won't touch an interface that shares an IP address with another.
+This will eventually change, but it probably won't happen soon.
+
+For now, you will have to give the ppp1 and ppp2 different addresses.</PRE>
+<H3><A name="kflags">ipsec_setup: Cannot adjust kernel flags</A></H3>
+<P>A mailing list message form technical lead Henry Spencer:</P>
+<PRE>&gt; When FreeS/WAN IPsec 1.7 is starting on my 2.0.38 Linux kernel the following
+&gt; error message is generated:
+&gt; ipsec_setup: Cannot adjust kernel flags, no /proc/sys/net/ipsec directory!
+&gt; What is supposed to create this directory and how can I fix this problem?
+
+I think that directory is a 2.2ism, although I'm not certain (I don't have
+a 2.0.xx system handy any more for testing).  Without it, some of the
+ipsec.conf config-setup flags won't work, but otherwise things should
+function. </PRE>
+<P>You also need to enable the<VAR> /proc</VAR> filesystem in your
+ kernel configuration for these operations to work.</P>
+<H3><A name="message_num">Message numbers (MI3, QR1, et cetera) in Pluto
+ messages</A></H3>
+<P>Pluto messages often indicate where Pluto is in the IKE protocols.
+ The letters indicate<STRONG> M</STRONG>ain mode or<STRONG> Q</STRONG>
+uick mode and<STRONG> I</STRONG>nitiator or<STRONG> R</STRONG>esponder.
+ The numerals are message sequence numbers. For more detail, see our<A href="#sequence">
+ IPsec section</A>.</P>
+<H3><A name="conn_name">Connection names in Pluto error messages</A></H3>
+<P>From Pluto programmer Hugh Redelmeier:</P>
+<PRE>| Jan 17 16:21:10 remus Pluto[13631]: &quot;jumble&quot; #1: responding to Main Mode from Road Warrior 130.205.82.46
+| Jan 17 16:21:11 remus Pluto[13631]: &quot;jumble&quot; #1: no suitable connection for peer @banshee.wittsend.com
+| 
+|     The connection &quot;jumble&quot; has nothing to do with the incoming
+| connection requests, which were meant for the connection &quot;banshee&quot;.
+
+You are right.  The message tells you which Connection Pluto is
+currently using, which need not be the right one.  It need not be the
+right one now for the negotiation to eventually succeed!  This is
+described in ipsec_pluto(8) in the section &quot;Road Warrior Support&quot;.
+
+There are two times when Pluto will consider switching Connections for
+a state object.  Both are in response to receiving ID payloads (one in
+Phase 1 / Main Mode and one in Phase 2 / Quick Mode).  The second is
+not unique to Road Warriors.  In fact, neither is the first any more
+(two connections for the same pair of hosts could differ in Phase 1 ID
+payload; probably nobody else has tried this).</PRE>
+<H3><A name="cantorient">Pluto: ... can't orient connection</A></H3>
+<P>Older versions of FreeS/WAN used this message. The same error now
+ gives the &quot;we have no ipsecN ...&quot; error described just below.</P>
+<H3><A name="no.interface">... we have no ipsecN interface for either
+ end of this connection</A></H3>
+<P>Your tunnel has no IP address which matches the IP address of any of
+ the available IPsec interfaces. Either you've misconfigured the
+ connection, or you need to define an appropriate IPsec interface
+ connection.<VAR> interfaces=%defaultroute</VAR> works in many cases.</P>
+<P>A longer story: Pluto needs to know whether it is running on the
+ machine which the connection description calls<VAR> left</VAR> or on<VAR>
+ right</VAR>. It figures that out by:</P>
+<UL>
+<LI>looking at the interfaces given in<VAR> interfaces=</VAR> lines in
+ the<VAR> config setup</VAR> section</LI>
+<LI>discovering the IP addresses for those interfaces</LI>
+<LI>searching for a match between those addresses and the ones given in<VAR>
+ left=</VAR> or<VAR> right=</VAR> lines.</LI>
+</UL>
+<P>Normally a match is found. Then Pluto knows where it is and can set
+ up other things (for example, if it is<VAR> left</VAR>) using
+ parameters such as<VAR> leftsubnet</VAR> and<VAR> leftnexthop</VAR>,
+ and sending its outgoing packets to<VAR> right</VAR>.</P>
+<P>If no match is found, it emits the above error message.</P>
+<H3><A name="noconn">Pluto: ... no connection is known</A></H3>
+<P>This error message occurs when a remote system attempts to negotiate
+ a connection and Pluto does not have a connection description that
+ matches what the remote system has requested. The most common cause is
+ a configuration error on one end or the other.</P>
+<P>Parameters involved in this match are<VAR> left</VAR>,<VAR> right</VAR>
+,<VAR> leftsubnet</VAR> and<VAR> rightsubnet</VAR>.</P>
+<P><STRONG>The match must be exact</STRONG>. For example, if your left
+ subnet is a.b.c.0/24 then neither a single machine in that net nor a
+ smaller subnet such as a.b.c.64/26 will be considered a match.</P>
+<P>The message can also occur when an appropriate description exists but
+ Pluto has not loaded it. Use an<VAR> auto=add</VAR> statement in the
+ connection description, or an<VAR> ipsec auto --add &lt;conn_name&gt;</VAR>
+ command, to correct this.</P>
+<P>An explanation from the Pluto developer:</P>
+<PRE>| Jul 12 15:00:22 sohar58 Pluto[574]: &quot;corp_road&quot; #2: cannot respond to IPsec
+| SA request because no connection is known for
+| 216.112.83.112/32===216.112.83.112...216.67.25.118
+
+This is the first message from the Pluto log showing a problem.  It
+means that PGPnet is trying to negotiate a set of SAs with this
+topology:
+
+216.112.83.112/32===216.112.83.112...216.67.25.118
+^^^^^^^^^^^^^^^^^   ^^^^^^^^^^^^^^   ^^^^^^^^^^^^^
+client on our side  our host         PGPnet host, no client
+
+None of the conns you showed look like this.
+
+Use
+        ipsec auto --status
+to see a snapshot of what connections are in pluto, what
+negotiations are going on, and what SAs are established.
+
+The leftsubnet= (client) in your conn is 216.112.83.64/26.  It must
+exactly match what pluto is looking for, and it does not.</PRE>
+<H3><A name="nosuit">Pluto: ... no suitable connection ...</A></H3>
+<P>This is similar to the<A href="#noconn"> no connection known</A>
+ error, but occurs at a different point in Pluto processing.</P>
+<P>Here is one of Claudia's messages explaining the problem:</P>
+<PRE>You write,
+
+&gt; What could be the reason of the following error? 
+&gt; &quot;no suitable connection for peer '@xforce'&quot;
+
+When a connection is initiated by the peer, Pluto must choose which entry in 
+the conf file best matches the incoming connection. A preliminary choice is 
+made on the basis of source and destination IPs, since that information is 
+available at that time. 
+
+A payload containing an ID arrives later in the negotiation. Based on this
+id and the *id= parameters, Pluto refines its conn selection. ...
+
+The message &quot;no suitable connection&quot; indicates that in this refining step,
+Pluto does not find a connection that matches that ID.
+
+Please see &quot;Selecting a connection when responding&quot; in man ipsec_pluto for
+more details.</PRE>
+<P>See also<A href="#conn_name"> Connection names in Pluto error
+ messages</A>.</P>
+<H3><A name="noconn.auth">Pluto: ... no connection has been authorized</A>
+</H3>
+<P>Here is one of Claudia's messages discussing this problem:</P>
+<PRE>You write,
+
+&gt;  May 22 10:46:31 debian Pluto[25834]: packet from x.y.z.p:10014: 
+&gt;  initial Main Mode message from x.y.z.p:10014 
+                            but no connection has been authorized
+
+This error occurs early in the connection negotiation process,
+at the first step of IKE negotiation (Main Mode), which is itself the 
+first of two negotiation phases involved in creating an IPSec connection.
+
+Here, Linux FreeS/WAN receives a packet from a potential peer, which 
+requests that they begin discussing a connection.
+
+The &quot;no connection has been authorized&quot; means that there is no connection 
+description in Linux FreeS/WAN's internal database that can be used to 
+link your ipsec interface with that peer.
+
+&quot;But of course I configured that connection!&quot; 
+
+It may be that the appropriate connection description exists in ipsec.conf 
+but has not been added to the database with ipsec auto --add myconn or the 
+auto=add method. Or, the connection description may be misconfigured.
+
+The only parameters that are relevant in this decision are left= and right= .
+Local and remote ports are also taken into account -- we see that the port 
+is printed in the message above -- but there is no way to control these
+in ipsec.conf.
+
+
+Failure at &quot;no connection has been authorized&quot; is similar to the
+&quot;no connection is known for...&quot; error in the FAQ, and the &quot;no suitable
+connection&quot; error described in the snapshot's FAQ. In all three cases,
+Linux FreeS/WAN is trying to match parameters received in the
+negotiation with the connection description in the local config file.
+
+As it receives more information, its matches take more parameters into 
+account, and become more precise:  first the pair of potential peers,
+then the peer IDs, then the endpoints (including any subnets).
+
+The &quot;no suitable connection for peer *&quot; occurs toward the end of IKE 
+(Main Mode) negotiation, when the IDs are matched.
+
+&quot;no connection is known for a/b===c...d&quot; is seen at the beginning of IPSec 
+(Quick Mode, phase 2) negotiation, when the connections are matched using
+left, right, and any information about the subnets.</PRE>
+<H3><A name="noDESsupport">Pluto: ... OAKLEY_DES_CBC is not supported.</A>
+</H3>
+<P>This message occurs when the other system attempts to negotiate a
+ connection using<A href="#DES"> single DES</A>, which we do not support
+ because it is<A href="#desnotsecure"> insecure</A>.</P>
+<P>Our interoperation document has suggestions for<A href="interop.html#noDES">
+ how to deal with</A> systems that attempt to use single DES.</P>
+<H3><A name="notransform">Pluto: ... no acceptable transform</A></H3>
+<P>This message means that the other gateway has made a proposal for
+ connection parameters, but nothing they proposed is acceptable to
+ Pluto. Possible causes include:</P>
+<UL>
+<LI>misconfiguration on either end</LI>
+<LI>policy incompatibilities, for example we require encrypted
+ connections but they are trying to create one with just authentication</LI>
+<LI>interoperation problems, for example they offer only single DES and
+ FreeS/WAN does not support that. See<A href="interop.html#interop.problem">
+ discussion</A> in our interoperation document.</LI>
+</UL>
+<P>A more detailed explanation, from Pluto programmer Hugh Redelmeier:</P>
+<PRE>Background:
+
+When one IKE system (for example, Pluto) is negotiating with another
+to create an SA, the Initiator proposes a bunch of choices and the
+Responder replies with one that it has selected.
+
+The structure of the choices is fairly complicated.  An SA payload
+contains a list of lists of &quot;Proposals&quot;.  The outer list is a set of
+choices: the selection must be from one element of this list.
+
+Each of these elements is a list of Proposals.  A selection must be
+made from each of the elements of the inner list.  In other words,
+*all* of them apply (that is how, for example, both AH and ESP can
+apply at once).
+
+Within each of these Proposals is a list of Transforms.  For each
+Proposal selected, one Transform must be selected (in other words,
+each Proposal provides a choice of Transforms).
+
+Each Transform is made up of a list of Attributes describing, well,
+attributes.  Such as lifetime of the SA.  Such as algorithm to be
+used.  All the Attributes apply to a Transform.
+
+You will have noticed a pattern here: layers alternate between being
+disjunctions (&quot;or&quot;) and conjunctions (&quot;and&quot;).
+
+For Phase 1 / Main Mode (negotiating an ISAKMP SA), this structure is
+cut back.  There must be exactly one Proposal.  So this degenerates to
+a list of Transforms, one of which must be chosen.
+
+In your case, no proposal was considered acceptable to Pluto (the
+Responder).  So negotiation ceased.  Pluto logs the reason it rejects
+each Transform.  So look back in the log to see what is going wrong.</PRE>
+<H3><A name="rsasigkey">rsasigkey dumps core</A></H3>
+ A comment on this error from Henry:
+<PRE>On Fri, 29 Jun 2001, Rodrigo Gruppelli wrote:
+&gt; ...Well, it seem that there's
+&gt; another problem with it. When I try to generate a pair of RSA keys,
+&gt; rsasigkey cores dump...
+
+*That* is a neon sign flashing &quot;GMP LIBRARY IS BROKEN&quot;.  Rsasigkey calls
+GMP a lot, and our own library a little bit, and that's very nearly all it
+does.  Barring bugs in its code or our library -- which have happened, but
+not very often -- a problem in rsasigkey is a problem in GMP.</PRE>
+<P>See the next question for how to deal with GMP errors.</P>
+<H3><A name="sig4">!Pluto failure!: ... exited with ... signal 4</A></H3>
+<P>Pluto has died. Signal 4 is SIGILL, illegal instruction.</P>
+<P>The most likely cause is that your<A href="#GMP"> GMP</A> (GNU
+ multi-precision) library is compiled for a different processor than
+ what you are running on. Pluto uses that library for its public key
+ calculations.</P>
+<P>Try getting the GMP sources and recompile for your processor type.
+ Most Linux distributions will include this source, or you can download
+ it from the<A href="http://www.swox.com/gmp/"> GMP home page</A>.</P>
+<H3><A name="econnrefused">ECONNREFUSED error message</A></H3>
+<P>From John Denker, on the mailing list:</P>
+<PRE>1)  The log message
+  some IKE message we sent has been rejected with 
+  ECONNREFUSED (kernel supplied no details)
+is much more suitable than the previous version.  Thanks.
+
+2) Minor suggestion for further improvement: it might be worth mentioning
+that the command
+  tcpdump -i eth1 icmp[0] != 8 and icmp[0] != 0
+is useful for tracking down the details in question.  We shouldn't expect
+all IPsec users to figure that out on their own.  The log message might
+even provide a hint as to where to look in the docs.</PRE>
+<P>Reply From Pluto developer Hugh Redelmeier</P>
+<PRE>Good idea.
+
+I've added a bit pluto(8)'s BUGS section along these lines.
+I didn't have the heart to lengthen this message.</PRE>
+<H3><A name="no_eroute">klips_debug: ... no eroute!</A></H3>
+<P>This message means<A href="#KLIPS"> KLIPS</A> has received a packet
+ for which no IPsec tunnel has been defined.</P>
+<P>Here is a more detailed duscussion from the team's tech support
+ person Claudia Schmeing, responding to a query on the mailing list:</P>
+<PRE>&gt; Why ipsec reports no eroute! ???? IP Masq... is disabled.
+
+In general, more information is required so that people on the list may
+give you informed input. See doc/prob.report.</PRE>
+<P>The document she refers to has since been replaced by a<A href="#prob.report">
+ section</A> of the troubleshooting document.</P>
+<PRE>However, I can make some general comments on this type of error.
+
+This error usually looks something like this (clipped from an archived
+message):
+
+&gt; ttl:64 proto:1 chk:45459 saddr:192.168.1.2 daddr:192.168.100.1
+&gt; ... klips_debug:ipsec_findroute: 192.168.1.2-&gt;192.168.100.1
+&gt; ... klips_debug:rj_match: * See if we match exactly as a host destination
+&gt; ... klips_debug:rj_match: ** try to match a leaf, t=0xc1a260b0
+&gt; ... klips_debug:rj_match: *** start searching up the tree, t=0xc1a260b0
+&gt; ... klips_debug:rj_match: **** t=0xc1a260c8
+&gt; ... klips_debug:rj_match: **** t=0xc1fe5960
+&gt; ... klips_debug:rj_match: ***** not found.
+&gt; ... klips_debug:ipsec_tunnel_start_xmit: Original head/tailroom: 2, 28
+&gt; ... klips_debug:ipsec_tunnel_start_xmit: no eroute!: ts=47.3030, dropping.
+
+
+What does this mean?
+- --------------------
+
+&quot;eroute&quot; stands for &quot;extended route&quot;, and is a special type of route 
+internal to Linux FreeS/WAN. For more information about this type of route, 
+see the section of man ipsec_auto on ipsec auto --route.
+
+&quot;no eroute!&quot; here means, roughly, that Linux FreeS/WAN cannot find an 
+appropriate tunnel that should have delivered this packet. Linux 
+FreeS/WAN therefore drops the packet, with the message &quot;no eroute! ...
+dropping&quot;, on the assumption that this packet is not a legitimate 
+transmission through a properly constructed tunnel.
+
+
+How does this situation come about?
+- -----------------------------------
+
+Linux FreeS/WAN has a number of connection descriptions defined in 
+ipsec.conf. These must be successfully brought &quot;up&quot; to form actual tunnels.
+(see doc/setup.html's step 15, man ipsec.conf and man ipsec_auto 
+for details).
+
+Such connections are often specific to the endpoints' IPs. However, in 
+some cases they may be more general, for example in the case of 
+Road Warriors where left or right is the special value %any.
+
+When Linux FreeS/WAN receives a packet, it verifies that the packet has
+come through a legitimate channel, by checking that there is an
+appropriate tunnel through which this packet might legitimately have
+arrived. This is the process we see above.
+
+First, it checks for an eroute that exactly matches the packet. In the 
+example above, we see it checking for a route that begins at 192.168.1.2
+and ends at 192.168.100.1. This search favours the most specific match that
+would apply to the route between these IPs. So, if there is a connection 
+description exactly matching these IPs, the search will end there. If not, 
+the code will search for a more general description matching the IPs.
+If there is no match, either specific or general, the packet will be
+dropped, as we see, above.
+
+Unless you are working with Road Warriors, only the first, specific part 
+of the matching process is likely to be relevant to you.
+
+
+&quot;But I defined the tunnel, and it came up, why do I have this error?&quot;
+- ---------------------------------------------------------------------
+
+One of the most common causes of this error is failure to specify enough
+connection descriptions to cover all needed tunnels between any two 
+gateways and their respective subnets. As you have noticed, troubleshooting
+this error may be complicated by the use of IP Masq. However, this error is
+not limited to cases where IP Masq is used. 
+
+See doc/configuration.html#multitunnel for a detailed example of the 
+solution to this type of problem.</PRE>
+<P>The documentation section she refers to is now<A href="#multitunnel">
+ here</A>.</P>
+<H3><A name="SAused">... trouble writing to /dev/ipsec ... SA already in
+ use</A></H3>
+<P>This error message occurs when two manual connections are set up with
+ the same SPI value.</P>
+<P>See the FAQ for<A href="#spi_error"> One manual connection works, but
+ second one fails</A>.</P>
+<H3><A name="ignore">... ignoring ... payload</A></H3>
+<P>This message is harmless. The IKE protocol provides for a number of
+ optional messages types:</P>
+<UL>
+<LI>delete SA</LI>
+<LI>initial contact</LI>
+<LI>vendor ID</LI>
+<LI>...</LI>
+</UL>
+<P>An implementation is never required to send these, but they are
+ allowed to. The receiver is not required to do anything with them.
+ FreeS/WAN ignores them, but notifies you via the logs.</P>
+<P>For the &quot;ignoring delete SA Payload&quot; message, see also our discussion
+ of cleaning up<A href="#deadtunnel"> dead tunnels</A>.</P>
+<H3><A name="unknown_rightcert">unknown parameter name &quot;rightcert&quot;</A></H3>
+<P>This message can appear when you've upgraded an X.509-enabled Linux
+ FreeS/WAN with a vanilla Linux FreeS/WAN. To use your X.509 configs you
+ will need to overwrite the new install with<A HREF="http://www.freeswan.ca">
+ Super FreeS/WAN</A>, or add the<A HREF="http://www.strongsec.ca/freeswan">
+ X.509 patch</A> by hand.</P>
+<H2><A name="spam">Why don't you restrict the mailing lists to reduce
+ spam?</A></H2>
+<P>As a matter of policy, some of our<A href="mail.html"> mailing lists</A>
+ need to be open to non-subscribers. Project management feel strongly
+ that maintaining this openness is more important than blocking spam.</P>
+<UL>
+<LI>Users should be able to get help or report bugs without subscribing.</LI>
+<LI>Even a user who is subscribed may not have access to his or her
+ subscribed account when he or she needs help, miles from home base in
+ the middle of setting up a client's gateway.</LI>
+<LI>There is arguably a legal requirement for this policy. A US resident
+ or citizen could be charged under munitions export laws for providing
+ technical assistance to a foreign cryptographic project. Such a charge
+ would be more easily defended if the discussion takes place in public,
+ on an open list.</LI>
+</UL>
+<P>This has been discussed several times at some length on the list. See
+ the<A href="#archive"> list archives</A>. Bringing the topic up again
+ is unlikely to be useful. Please don't. Or at the very least, please
+ don't without reading the archives and being certain that whatever you
+ are about to suggest has not yet been discussed.</P>
+<P>Project technical lead Henry Spencer summarised one discussion:</P>
+<BLOCKQUOTE> For the third and last time: this list *will* *not* do
+ address-based filtering. This is a policy decision, not an
+ implementation problem. The decision is final, and is not open to
+ discussion. This needs to be communicated better to people, and steps
+ are being taken to do that.</BLOCKQUOTE>
+<P>Adding this FAQ section is one of the steps he refers to.</P>
+<P>You have various options other than just putting up with the spam,
+ filtering it yourself, or unsubscribing:</P>
+<UL>
+<LI>subscribe only to one or both of our lists with restricted posting
+ rules:
+<UL>
+<LI><A href="mailto:briefs@lists.freeswan.org?body=subscribe">briefs</A>
+, weekly list summaries</LI>
+<LI><A href="mailto:announce@lists.freeswan.org?body=subscribe">announce</A>
+, project-related announcements</LI>
+</UL>
+</LI>
+<LI>read the other lists via the<A href="#archive"> archives</A></LI>
+</UL>
+<P>A number of tools are available to filter mail.</P>
+<UL>
+<LI>Many mail readers include some filtering capability.</LI>
+<LI>Many Linux distributions include<A href="http://www.procmail.org/">
+ procmail(8)</A> for server-side filtering.</LI>
+<LI>The<A href="http://www.spambouncer.org/"> Spam Bouncer</A> is a set
+ of procmail(8) filters designed to combat spam.</LI>
+<LI>Roaring Penguin have a<A href="http://www.roaringpenguin.com/mimedefang/">
+ MIME defanger</A> that removes potentially dangerous attachments.</LI>
+</UL>
+<P>If you use your ISP's mail server rather than running your own,
+ consider suggesting to the ISP that they tag suspected spam as<A href="http://www.msen.com/1997/spam.html#SUSPECTED">
+ this ISP</A> does. They could just refuse mail from dubious sources,
+ but that is tricky and runs some risk of losing valuable mail or
+ senselessly annoying senders and their admins. However, they can safely
+ tag and deliver dubious mail. The tags can greatly assist your
+ filtering.</P>
+<P>For information on tracking down spammers, see these<A href="http://www.rahul.net/falk/#howtos">
+ HowTos</A>, or the<A href="http://www.sputum.com/index2.html"> Sputum</A>
+ site. Sputum have a Linux anti-spam screensaver available for download.</P>
+<P>Here is a more detailed message from Henry:</P>
+<PRE>On Mon, 15 Jan 2001, Jay Vaughan wrote:
+&gt; I know I'm flogging a dead horse here, but I'm curious as to the reasons for
+&gt; an aversion for a subscriber-only mailing list?
+
+Once again:  for legal reasons, it is important that discussions of these
+things be held in a public place -- the list -- and we do not want to
+force people to subscribe to the list just to ask one question, because
+that may be more than merely inconvenient for them.  There are also real
+difficulties with people who are temporarily forced to use alternate
+addresses; that is precisely the time when they may be most in need of
+help, yet a subscribers-only policy shuts them out.
+
+These issues do not apply to most mailing lists, but for a list that is
+(necessarily) the primary user support route for a crypto package, they
+are very important.  This is *not* an ordinary mailing list; it has to
+function under awkward constraints that make various simplistic solutions
+inapplicable or undesirable. 
+
+&gt; We're *ALL* sick of hearing about list management problems, not just you
+&gt; old-timers, so why don't you DO SOMETHING EFFECTIVE ABOUT IT...
+
+Because it's a lot harder than it looks, and many existing &quot;solutions&quot;
+have problems when examined closely.
+
+&gt; A suggestion for you, based on 10 years of experience with management of my
+&gt; own mailing lists would be to use mailman, which includes pretty much every
+&gt; feature under the sun that you guys need and want, plus some.  The URL for
+&gt; mailman...
+
+I assure you, we're aware of mailman.  Along with a whole bunch of others,
+including some you almost certainly have never heard of (I hadn't!).
+
+&gt; As for the argument that the list shouldn't be configured to enforce
+&gt; subscription - I contend that it *SHOULD* AT LEAST require manual address
+&gt; verification in order for posts to be redirected.
+
+You do realize, I hope, that interposing such a manual step might cause
+your government to decide that this is not truly a public forum, and thus
+you could go to jail if you don't get approval from them before mailing to
+it?  If you think this sounds irrational, your government is noted for
+making irrational decisions in this area; we can't assume that they will
+suddenly start being sensible.  See above about awkward constraints.  You
+may be willing to take the risk, but we can't, in good conscience, insist
+that all users with problems do so. 
+
+                                                          Henry Spencer
+                                                       henry@spsystems.net</PRE>
+<P>and a message on the topic from project leader John Gilmore:</P>
+<PRE>Subject: Re: The linux-ipsec list's topic
+   Date: Sat, 30 Dec 2000
+   From: John Gilmore &lt;gnu@toad.com&gt;
+
+I'll post this single message, once only, in this discussion, and then
+not burden the list with any further off-topic messages.  I encourage
+everyone on the list to restrain themself from posting ANY off-topic
+messages to the linux-ipsec list.
+
+The topic of the linux-ipsec mailing list is the FreeS/WAN software.
+
+I frequently see &quot;discussions about spam on a list&quot; overwhelm the
+volume of &quot;actual spam&quot; on a list. BOTH kinds of messages are
+off-topic messages.  Twenty anti-spam messages take just as long to
+detect and discard as twenty spam messages.
+
+The Linux-ipsec list encourages on-topic messages from people who have
+not joined the list itself.  We will not censor messages to the list
+based on where they originate, or what return address they contain.
+In other words, non-subscribers ARE allowed to post, and this will not
+change.  My own valid contributions have been rejected out-of-hand by
+too many other mailing lists for me to want to impose that censorship
+on anybody else's contributions.  And every day I see the damage that
+anti-spam zeal is causing in many other ways; that zeal is far more
+damaging to the culture of the Internet than the nuisance of spam.
+
+In general, it is the responsibility of recipients to filter,
+prioritize, or otherwise manage the handling of email that comes to
+them.  It is not the responsibility of the rest of the Internet
+community to refrain from sending messages to recipients that they
+might not want to see.  If your software infrastructure for managing
+your incoming email is insufficient, then improve it.  If you think
+the signal-to-noise ratio on linux-ipsec is too poor, then please
+unsubscribe.  But don't further increase the noise by posting to the
+linux-ipsec list about those topics.
+
+        John Gilmore
+        founder &amp; sponsor, FreeS/WAN project</PRE>
+<HR>
+<H1><A name="manpages">FreeS/WAN manual pages</A></H1>
+<P>The various components of Linux FreeS/WAN are of course documented in
+ standard Unix manual pages, accessible via the man(1) command.</P>
+<P>Links here take you to an HTML version of the man pages.</P>
+<H2><A name="man.file">Files</A></H2>
+<DL>
+<DT><A href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</A></DT>
+<DD>IPsec configuration and connections</DD>
+<DT><A href="manpage.d/ipsec.secrets.5.html">ipsec.secrets(5)</A></DT>
+<DD>secrets for IKE authentication, either pre-shared keys or RSA
+ private keys</DD>
+</DL>
+<P>These files are also discussed in the<A href="config.html">
+ configuration</A> section.</P>
+<H2><A name="man.command">Commands</A></H2>
+<P>Many users will never give most of the FreeS/WAN commands directly.
+ Configure the files listed above correctly and everything should be
+ automatic.</P>
+<P>The exceptions are commands for mainpulating the<A href="#RSA"> RSA</A>
+ keys used in Pluto authentication:</P>
+<DL>
+<DT><A href="manpage.d/ipsec_rsasigkey.8.html">ipsec_rsasigkey(8)</A></DT>
+<DD>generate keys</DD>
+<DT><A href="manpage.d/ipsec_newhostkey.8.html">ipsec_newhostkey(8)</A></DT>
+<DD>generate keys in a convenient format</DD>
+<DT><A href="manpage.d/ipsec_showhostkey.8.html">ipsec_showhostkey(8)</A>
+</DT>
+<DD>extract<A href="#RSA"> RSA</A> keys from<A href="manpage.d/ipsec.secrets.5.html">
+ ipsec.secrets(5)</A> (or optionally, another file) and format them for
+ insertion in<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf(5)</A> or
+ in DNS records</DD>
+</DL>
+<P>Note that:</P>
+<UL>
+<LI>These keys are for<STRONG> authentication only</STRONG>. They are<STRONG>
+ not secure for encryption</STRONG>.</LI>
+<LI>The utility uses random(4) as a source of<A href="#random"> random
+ numbers</A>. This may block for some time if there is not enough
+ activity on the machine to provide the required entropy. You may want
+ to give it some bogus activity such as random mouse movements or some
+ command such as<NOBR> <TT>du /usr &gt; /dev/null &amp;</TT>.</LI>
+</UL>
+<P>The following commands are fairly likely to be used, if only for
+ testing and status checks:</P>
+<DL>
+<DT><A href="manpage.d/ipsec.8.html">ipsec(8)</A></DT>
+<DD>invoke IPsec utilities</DD>
+<DT><A href="manpage.d/ipsec_setup.8.html">ipsec_setup(8)</A></DT>
+<DD>control IPsec subsystem</DD>
+<DT><A href="manpage.d/ipsec_auto.8.html">ipsec_auto(8)</A></DT>
+<DD>control automatically-keyed IPsec connections</DD>
+<DT><A href="manpage.d/ipsec_manual.8.html">ipsec_manual(8)</A></DT>
+<DD>take manually-keyed IPsec connections up and down</DD>
+<DT><A href="manpage.d/ipsec_ranbits.8.html">ipsec_ranbits(8)</A></DT>
+<DD>generate random bits in ASCII form</DD>
+<DT><A href="manpage.d/ipsec_look.8.html">ipsec_look(8)</A></DT>
+<DD>show minimal debugging information</DD>
+<DT><A href="manpage.d/ipsec_barf.8.html">ipsec_barf(8)</A></DT>
+<DD>spew out collected IPsec debugging information</DD>
+</DL>
+<P>The lower-level utilities listed below are normally invoked via
+ scripts listed above, but they can also be used directly when required.</P>
+<DL>
+<DT><A href="manpage.d/ipsec_eroute.8.html">ipsec_eroute(8)</A></DT>
+<DD>manipulate IPsec extended routing tables</DD>
+<DT><A href="manpage.d/ipsec_klipsdebug.8.html">ipsec_klipsdebug(8)</A></DT>
+<DD>set Klips (kernel IPsec support) debug features and level</DD>
+<DT><A href="manpage.d/ipsec_pluto.8.html">ipsec_pluto(8)</A></DT>
+<DD>IPsec IKE keying daemon</DD>
+<DT><A href="manpage.d/ipsec_spi.8.html">ipsec_spi(8)</A></DT>
+<DD>manage IPsec Security Associations</DD>
+<DT><A href="manpage.d/ipsec_spigrp.8.html">ipsec_spigrp(8)</A></DT>
+<DD>group/ungroup IPsec Security Associations</DD>
+<DT><A href="manpage.d/ipsec_tncfg.8.html">ipsec_tncfg(8)</A></DT>
+<DD>associate IPsec virtual interface with real interface</DD>
+<DT><A href="manpage.d/ipsec_whack.8.html">ipsec_whack(8)</A></DT>
+<DD>control interface for IPsec keying daemon</DD>
+</DL>
+<H2><A name="man.lib">Library routines</A></H2>
+<DL>
+<DT><A href="manpage.d/ipsec_atoaddr.3.html">ipsec_atoaddr(3)</A></DT>
+<DT><A href="manpage.d/ipsec_addrtoa.3.html">ipsec_addrtoa(3)</A></DT>
+<DD>convert Internet addresses to and from ASCII</DD>
+<DT><A href="manpage.d/ipsec_atosubnet.3.html">ipsec_atosubnet(3)</A></DT>
+<DT><A href="manpage.d/ipsec_subnettoa.3.html">ipsec_subnettoa(3)</A></DT>
+<DD>convert subnet/mask ASCII form to and from addresses</DD>
+<DT><A href="manpage.d/ipsec_atoasr.3.html">ipsec_atoasr(3)</A></DT>
+<DD>convert ASCII to Internet address, subnet, or range</DD>
+<DT><A href="manpage.d/ipsec_rangetoa.3.html">ipsec_rangetoa(3)</A></DT>
+<DD>convert Internet address range to ASCII</DD>
+<DT>ipsec_atodata(3)</DT>
+<DT><A href="manpage.d/ipsec_datatoa.3.html">ipsec_datatoa(3)</A></DT>
+<DD>convert binary data from and to ASCII formats</DD>
+<DT><A href="manpage.d/ipsec_atosa.3.html">ipsec_atosa(3)</A></DT>
+<DT><A href="manpage.d/ipsec_satoa.3.html">ipsec_satoa(3)</A></DT>
+<DD>convert IPsec Security Association IDs to and from ASCII</DD>
+<DT><A href="manpage.d/ipsec_atoul.3.html">ipsec_atoul(3)</A></DT>
+<DT><A href="manpage.d/ipsec_ultoa.3.html">ipsec_ultoa(3)</A></DT>
+<DD>convert unsigned-long numbers to and from ASCII</DD>
+<DT><A href="manpage.d/ipsec_goodmask.3.html">ipsec_goodmask(3)</A></DT>
+<DD>is this Internet subnet mask a valid one?</DD>
+<DT><A href="manpage.d/ipsec_masktobits.3.html">ipsec_masktobits(3)</A></DT>
+<DD>convert Internet subnet mask to bit count</DD>
+<DT><A href="manpage.d/ipsec_bitstomask.3.html">ipsec_bitstomask(3)</A></DT>
+<DD>convert bit count to Internet subnet mask</DD>
+<DT><A href="manpage.d/ipsec_optionsfrom.3.html">ipsec_optionsfrom(3)</A>
+</DT>
+<DD>read additional ``command-line'' options from file</DD>
+<DT><A href="manpage.d/ipsec_subnetof.3.html">ipsec_subnetof(3)</A></DT>
+<DD>given Internet address and subnet mask, return subnet number</DD>
+<DT><A href="manpage.d/ipsec_hostof.3.html">ipsec_hostof(3)</A></DT>
+<DD>given Internet address and subnet mask, return host part</DD>
+<DT><A href="manpage.d/ipsec_broadcastof.3.html">ipsec_broadcastof(3)</A>
+</DT>
+<DD>given Internet address and subnet mask, return broadcast address</DD>
+</DL>
+<HR>
+<H1><A name="firewall">FreeS/WAN and firewalls</A></H1>
+<P>FreeS/WAN, or other IPsec implementations, frequently run on gateway
+ machines, the same machines running firewall or packet filtering code.
+ This document discusses the relation between the two.</P>
+<P>The firewall code in 2.4 and later kernels is called Netfilter. The
+ user-space utility to manage a firewall is iptables(8). See the<A href="http://netfilter.samba.org">
+ netfilter/iptables web site</A> for details.</P>
+<H2><A name="filters">Filtering rules for IPsec packets</A></H2>
+<P>The basic constraint is that<STRONG> an IPsec gateway must have
+ packet filters that allow IPsec packets</STRONG>, at least when talking
+ to other IPsec gateways:</P>
+<UL>
+<LI>UDP port 500 for<A href="#IKE"> IKE</A> negotiations</LI>
+<LI>protocol 50 if you use<A href="#ESP"> ESP</A> encryption and/or
+ authentication (the typical case)</LI>
+<LI>protocol 51 if you use<A href="#AH"> AH</A> packet-level
+ authentication</LI>
+</UL>
+<P>Your gateway and the other IPsec gateways it communicates with must
+ be able to exchange these packets for IPsec to work. Firewall rules
+ must allow UDP 500 and at least one of<A href="#AH"> AH</A> or<A href="#ESP">
+ ESP</A> on the interface that communicates with the other gateway.</P>
+<P>For nearly all FreeS/WAN applications, you must allow UDP port 500
+ and the ESP protocol.</P>
+<P>There are two ways to set this up:</P>
+<DL>
+<DT>easier but less flexible</DT>
+<DD>Just set up your firewall scripts at boot time to allow IPsec
+ packets to and from your gateway. Let FreeS/WAN reject any bogus
+ packets.</DD>
+<DT>more work, giving you more precise control</DT>
+<DD>Have the<A href="manpage.d/ipsec_pluto.8.html"> ipsec_pluto(8)</A>
+ daemon call scripts to adjust firewall rules dynamically as required.
+ This is done by naming the scripts in the<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A> variables<VAR> prepluto=</VAR>,<VAR> postpluto=</VAR>
+,<VAR> leftupdown=</VAR> and<VAR> rightupdown=</VAR>.</DD>
+</DL>
+<P>Both methods are described in more detail below.</P>
+<H2><A name="examplefw">Firewall configuration at boot</A></H2>
+<P>It is possible to set up both firewalling and IPsec with appropriate
+ scripts at boot and then not use<VAR> leftupdown=</VAR> and<VAR>
+ rightupdown=</VAR>, or use them only for simple up and down operations.</P>
+<P>Basically, the technique is</P>
+<UL>
+<LI>allow IPsec packets (typically, IKE on UDP port 500 plus ESP,
+ protocol 50)
+<UL>
+<LI>incoming, if the destination address is your gateway (and
+ optionally, only from known senders)</LI>
+<LI>outgoing, with the from address of your gateway (and optionally,
+ only to known receivers)</LI>
+</UL>
+</LI>
+<LI>let<A href="#Pluto"> Pluto</A> deal with IKE</LI>
+<LI>let<A href="#KLIPS"> KLIPS</A> deal with ESP</LI>
+</UL>
+<P>Since Pluto authenticates its partners during the negotiation, and
+ KLIPS drops packets for which no tunnel has been negotiated, this may
+ be all you need.</P>
+<H3><A name="simple.rules">A simple set of rules</A></H3>
+<P>In simple cases, you need only a few rules, as in this example:</P>
+<PRE># allow IPsec
+#
+# IKE negotiations
+iptables -I INPUT  -p udp --sport 500 --dport 500 -j ACCEPT
+iptables -I OUTPUT -p udp --sport 500 --dport 500 -j ACCEPT
+# ESP encryption and authentication
+iptables -I INPUT  -p 50 -j ACCEPT
+iptables -I OUTPUT -p 50 -j ACCEPT
+</PRE>
+<P>This should be all you need to allow IPsec through<VAR> lokkit</VAR>,
+ which ships with Red Hat 9, on its medium security setting. Once you've
+ tweaked to your satisfaction, save your active rule set with:</P>
+<PRE>service iptables save</PRE>
+<H3><A name="complex.rules">Other rules</A></H3>
+ You can add additional rules, or modify existing ones, to work with
+ IPsec and with your network and policies. We give a some examples in
+ this section.
+<P>However, while it is certainly possible to create an elaborate set of
+ rules yourself (please let us know via the<A href="mail.html"> mailing
+ list</A> if you do), it may be both easier and more secure to use a set
+ which has already been published and tested.</P>
+<P>The published rule sets we know of are described in the<A href="#rules.pub">
+ next section</A>.</P>
+<H4><A NAME="7_2_2_1">Adding additional rules</A></H4>
+ If necessary, you can add additional rules to:
+<DL>
+<DT>reject IPsec packets that are not to or from known gateways</DT>
+<DD>This possibility is discussed in more detail<A href="#unknowngate">
+ later</A></DD>
+<DT>allow systems behind your gateway to build IPsec tunnels that pass
+ through the gateway</DT>
+<DD>This possibility is discussed in more detail<A href="#through">
+ later</A></DD>
+<DT>filter incoming packets emerging from KLIPS.</DT>
+<DD>Firewall rules can recognise packets emerging from IPsec. They are
+ marked as arriving on an interface such as<VAR> ipsec0</VAR>, rather
+ than<VAR> eth0</VAR>,<VAR> ppp0</VAR> or whatever.</DD>
+</DL>
+<P>It is therefore reasonably straightforward to filter these packets in
+ whatever way suits your situation.</P>
+<H4><A NAME="7_2_2_2">Modifying existing rules</A></H4>
+<P>In some cases rules that work fine before you add IPsec may require
+ modification to work with IPsec.</P>
+<P>This is especially likely for rules that deal with interfaces on the
+ Internet side of your system. IPsec adds a new interface; often the
+ rules must change to take account of that.</P>
+<P>For example, consider the rules given in<A href="http://www.netfilter.org/documentation/HOWTO//packet-filtering-HOWTO-5.html">
+ this section</A> of the Netfilter documentation:</P>
+<PRE>Most people just have a single PPP connection to the Internet, and don't
+want anyone coming back into their network, or the firewall:
+
+    ## Insert connection-tracking modules (not needed if built into kernel).
+    # insmod ip_conntrack
+    # insmod ip_conntrack_ftp
+
+    ## Create chain which blocks new connections, except if coming from inside.
+    # iptables -N block
+    # iptables -A block -m state --state ESTABLISHED,RELATED -j ACCEPT
+    # iptables -A block -m state --state NEW -i ! ppp0 -j ACCEPT
+    # iptables -A block -j DROP
+
+    ## Jump to that chain from INPUT and FORWARD chains.
+    # iptables -A INPUT -j block
+    # iptables -A FORWARD -j block</PRE>
+<P>On an IPsec gateway, those rules may need to be modified. The above
+ allows new connections from<EM> anywhere except ppp0</EM>. That means
+ new connections from ipsec0 are allowed.</P>
+<P>Do you want to allow anyone who can establish an IPsec connection to
+ your gateway to initiate TCP connections to any service on your
+ network? Almost certainly not if you are using opportunistic
+ encryption. Quite possibly not even if you have only explicitly
+ configured connections.</P>
+<P>To disallow incoming connections from ipsec0, change the middle
+ section above to:</P>
+<PRE>    ## Create chain which blocks new connections, except if coming from inside.
+    # iptables -N block
+    # iptables -A block -m state --state ESTABLISHED,RELATED -j ACCEPT
+    # iptables -A block -m state --state NEW -i ppp+ -j DROP
+    # iptables -A block -m state --state NEW -i ipsec+ -j DROP
+    # iptables -A block -m state --state NEW -i -j ACCEPT
+    # iptables -A block -j DROP</PRE>
+<P>The original rules accepted NEW connections from anywhere except
+ ppp0. This version drops NEW connections from any PPP interface (ppp+)
+ and from any ipsec interface (ipsec+), then accepts the survivors.</P>
+<P>Of course, these are only examples. You will need to adapt them to
+ your own situation.</P>
+<H3><A name="rules.pub">Published rule sets</A></H3>
+<P>Several sets of firewall rules that work with FreeS/WAN are
+ available.</P>
+<H4><A name="Ranch.trinity">Scripts based on Ranch's work</A></H4>
+<P>One user, Rob Hutton, posted his boot time scripts to the mailing
+ list, and we included them in previous versions of this documentation.
+ They are still available from our<A href="http://www.freeswan.org/freeswan_trees/freeswan-1.5/doc/firewall.html#examplefw">
+ web site</A>. However, they were for an earlier FreeS/WAN version so we
+ no longer recommend them. Also, they had some bugs. See this<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/04/msg00316.html">
+ message</A>.</P>
+<P>Those scripts were based on David Ranch's scripts for his &quot;Trinity
+ OS&quot; for setting up a secure Linux. Check his<A href="http://www.ecst.csuchico.edu/~dranch/LINUX/index-linux.html">
+ home page</A> for the latest version and for information on his<A href="#ranch">
+ book</A> on securing Linux. If you are going to base your firewalling
+ on Ranch's scripts, we recommend using his latest version, and sending
+ him any IPsec modifications you make for incorporation into later
+ versions.</P>
+<H4><A name="seawall">The Seattle firewall</A></H4>
+<P>We have had several mailing lists reports of good results using
+ FreeS/WAN with Seawall (the Seattle Firewall). See that project's<A href="http://seawall.sourceforge.net/">
+ home page</A> on Sourceforge.</P>
+<H4><A name="rcf">The RCF scripts</A></H4>
+<P>Another set of firewall scripts with IPsec support are the RCF or
+ rc.firewall scripts. See their<A href="http://jsmoriss.mvlan.net/linux/rcf.html">
+ home page</A>.</P>
+<H4><A name="asgard">Asgard scripts</A></H4>
+<P><A href="http://heimdall.asgardsrealm.net/linux/firewall/">Asgard's
+ Realm</A> has set of firewall scripts with FreeS/WAN support, for 2.4
+ kernels and iptables.</P>
+<H4><A name="user.scripts">User scripts from the mailing list</A></H4>
+<P>One user gave considerable detail on his scripts, including
+ supporting<A href="#IPX"> IPX</A> through the tunnel. His message was
+ too long to conveniently be quoted here, so I've put it in a<A href="user_examples.html">
+ separate file</A>.</P>
+<H2><A name="updown">Calling firewall scripts, named in ipsec.conf(5)</A>
+</H2>
+<P>The<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf(5)</A>
+ configuration file has three pairs of parameters used to specify an
+ interface between FreeS/WAN and firewalling code.</P>
+<P>Note that using these is not required if you have a static firewall
+ setup. In that case, you just set your firewall up at boot time (in a
+ way that permits the IPsec connections you want) and do not change it
+ thereafter. Omit all the FreeS/WAN firewall parameters and FreeS/WAN
+ will not attempt to adjust firewall rules at all. See<A href="#examplefw">
+ above</A> for some information on appropriate scripts.</P>
+<P>However, if you want your firewall rules to change when IPsec
+ connections change, then you need to use these parameters.</P>
+<H3><A name="pre_post">Scripts called at IPsec start and stop</A></H3>
+<P>One pair of parmeters are set in the<VAR> config setup</VAR> section
+ of the<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf(5)</A> file and
+ affect all connections:</P>
+<DL>
+<DT>prepluto=</DT>
+<DD>script to be called before<A href="manpage.d/ipsec_pluto.8.html">
+ pluto(8)</A> IKE daemon is started.</DD>
+<DT>postpluto=</DT>
+<DD>script to be called after<A href="manpage.d/ipsec_pluto.8.html">
+ pluto(8)</A> IKE daemon is stopped.</DD>
+</DL>
+ These parameters allow you to change firewall parameters whenever IPsec
+ is started or stopped.
+<P>They can also be used in other ways. For example, you might have<VAR>
+ prepluto</VAR> add a module to your kernel for the secure network
+ interface or make a dialup connection, and then have<VAR> postpluto</VAR>
+ remove the module or take the connection down.</P>
+<H3><A name="up_down">Scripts called at connection up and down</A></H3>
+<P>The other parameters are set in connection descriptions. They can be
+ set in individual connection descriptions, and could even call
+ different scripts for each connection for maximum flexibility. In most
+ applications, however, it makes sense to use only one script and to
+ call it from<VAR> conn %default</VAR> section so that it applies to all
+ connections.</P>
+<P>You can:</P>
+<DL>
+<DT><STRONG>either</STRONG></DT>
+<DD>set<VAR> leftfirewall=yes</VAR> or<VAR> rightfirewall=yes</VAR> to
+ use our supplied default script</DD>
+<DT><STRONG>or</STRONG></DT>
+<DD>assign a name in a<VAR> leftupdown=</VAR> or<VAR> rightupdown=</VAR>
+ line to use your own script</DD>
+</DL>
+<P>Note that<STRONG> only one of these should be used</STRONG>. You
+ cannot sensibly use both. Since<STRONG> our default script is obsolete</STRONG>
+ (designed for firewalls using<VAR> ipfwadm(8)</VAR> on 2.0 kernels),
+ most users who need this service will<STRONG> need to write a custom
+ script</STRONG>.</P>
+<H4><A name="fw.default">The default script</A></H4>
+<P>We supply a default script named<VAR> _updown</VAR>.</P>
+<DL>
+<DT>leftfirewall=</DT>
+<DD></DD>
+<DT>rightfirewall=</DT>
+<DD>indicates that the gateway is doing firewalling and that<A href="manpage.d/ipsec_pluto.8.html">
+ pluto(8)</A> should poke holes in the firewall as required.</DD>
+</DL>
+<P>Set these to<VAR> yes</VAR> and Pluto will call our default script<VAR>
+ _updown</VAR> with appropriate arguments whenever it:</P>
+<UL>
+<LI>starts or stops IPsec services</LI>
+<LI>brings a connection up or down</LI>
+</UL>
+<P>The supplied default<VAR> _updown</VAR> script is appropriate for
+ simple cases using the<VAR> ipfwadm(8)</VAR> firewalling package.</P>
+<H4><A name="userscript">User-written scripts</A></H4>
+<P>You can also write your own script and have Pluto call it. Just put
+ the script's name in one of these<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A> lines:</P>
+<DL>
+<DT>leftupdown=</DT>
+<DD></DD>
+<DT>rightupdown=</DT>
+<DD>specifies a script to call instead of our default script<VAR>
+ _updown</VAR>.</DD>
+</DL>
+<P>Your script should take the same arguments and use the same
+ environment variables as<VAR> _updown</VAR>. See the &quot;updown command&quot;
+ section of the<A href="manpage.d/ipsec_pluto.8.html"> ipsec_pluto(8)</A>
+ man page for details.</P>
+<P>Note that<STRONG> you should not modify our _updown script in place</STRONG>
+. If you did that, then upgraded FreeS/WAN, the upgrade would install a
+ new default script, overwriting your changes.</P>
+<H3><A name="ipchains.script">Scripts for ipchains or iptables</A></H3>
+<P>Our<VAR> _updown</VAR> is for firewalls using<VAR> ipfwadm(8)</VAR>,
+ the firewall code for the 2.0 series of Linux kernels. If you are using
+ the more recent packages<VAR> ipchains(8)</VAR> (for 2.2 kernels) or<VAR>
+ iptables(8)</VAR> (2.4 kernels), then you must do one of:</P>
+<UL>
+<LI>use static firewall rules which are set up at boot time as described<A
+href="#examplefw"> above</A> and do not need to be changed by Pluto</LI>
+<LI>limit yourself to ipchains(8)'s ipfwadm(8) emulation mode in order
+ to use our script</LI>
+<LI>write your own script and call it with<VAR> leftupdown</VAR> and<VAR>
+ rightupdown</VAR>.</LI>
+</UL>
+<P>You can write a script to do whatever you need with firewalling.
+ Specify its name in a<VAR> [left|right]updown=</VAR> parameter in<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A> and Pluto will automatically call it for you.</P>
+<P>The arguments Pluto passes such a script are the same ones it passes
+ to our default _updown script, so the best way to build yours is to
+ copy ours and modify the copy.</P>
+<P>Note, however, that<STRONG> you should not modify our _updown script
+ in place</STRONG>. If you did that, then upgraded FreeS/WAN, the
+ upgrade would install a new default script, overwriting your changes.</P>
+<H2><A name="NAT">A complication: IPsec vs. NAT</A></H2>
+<P><A href="#NAT.gloss">Network Address Translation</A>, also known as
+ IP masquerading, is a method of allocating IP addresses dynamically,
+ typically in circumstances where the total number of machines which
+ need to access the Internet exceeds the supply of IP addresses.</P>
+<P>Any attempt to perform NAT operations on IPsec packets<EM> between
+ the IPsec gateways</EM> creates a basic conflict:</P>
+<UL>
+<LI>IPsec wants to authenticate packets and ensure they are unaltered on
+ a gateway-to-gateway basis</LI>
+<LI>NAT rewrites packet headers as they go by</LI>
+<LI>IPsec authentication fails if packets are rewritten anywhere between
+ the IPsec gateways</LI>
+</UL>
+<P>For<A href="#AH"> AH</A>, which authenticates parts of the packet
+ header including source and destination IP addresses, this is fatal. If
+ NAT changes those fields, AH authentication fails.</P>
+<P>For<A href="#IKE"> IKE</A> and<A href="#ESP"> ESP</A> it is not
+ necessarily fatal, but is certainly an unwelcome complication.</P>
+<H3><A name="nat_ok">NAT on or behind the IPsec gateway works</A></H3>
+<P>This problem can be avoided by having the masquerading take place<EM>
+ on or behind</EM> the IPsec gateway.</P>
+<P>This can be done physically with two machines, one physically behind
+ the other. A picture, using SG to indicate IPsec<STRONG> S</STRONG>
+ecurity<STRONG> G</STRONG>ateways, is:</P>
+<PRE>      clients --- NAT ----- SG ---------- SG
+                  two machines</PRE>
+<P>In this configuration, the actual client addresses need not be given
+ in the<VAR> leftsubnet=</VAR> parameter of the FreeS/WAN connection
+ description. The security gateway just delivers packets to the NAT box;
+ it needs only that machine's address. What that machine does with them
+ does not affect FreeS/WAN.</P>
+<P>A more common setup has one machine performing both functions:</P>
+<PRE>      clients ----- NAT/SG ---------------SG
+                  one machine</PRE>
+<P>Here you have a choice of techniques depending on whether you want to
+ make your client subnet visible to clients on the other end:</P>
+<UL>
+<LI>If you want the single gateway to behave like the two shown above,
+ with your clients hidden behind the NAT, then omit the<VAR> leftsubnet=</VAR>
+ parameter. It then defaults to the gateway address. Clients on the
+ other end then talk via the tunnel only to your gateway. The gateway
+ takes packets emerging from the tunnel, applies normal masquerading,
+ and forwards them to clients.</LI>
+<LI>If you want to make your client machines visible, then give the
+ client subnet addresses as the<VAR> leftsubnet=</VAR> parameter in the
+ connection description and
+<DL>
+<DT>either</DT>
+<DD>set<VAR> leftfirewall=yes</VAR> to use the default<VAR> updown</VAR>
+ script</DD>
+<DT>or</DT>
+<DD>use your own script by giving its name in a<VAR> leftupdown=</VAR>
+ parameter</DD>
+</DL>
+ These scripts are described in their own<A href="#updown"> section</A>.
+<P>In this case, no masquerading is done. Packets to or from the client
+ subnet are encrypted or decrypted without any change to their client
+ subnet addresses, although of course the encapsulating packets use
+ gateway addresses in their headers. Clients behind the right security
+ gateway see a route via that gateway to the left subnet.</P>
+</LI>
+</UL>
+<H3><A name="nat_bad">NAT between gateways is problematic</A></H3>
+<P>We recommend not trying to build IPsec connections which pass through
+ a NAT machine. This setup poses problems:</P>
+<PRE>      clients --- SG --- NAT ---------- SG</PRE>
+<P>If you must try it, some references are:</P>
+<UL>
+<LI>Jean_Francois Nadeau's document on doing<A href="http://jixen.tripod.com/#NATed gateways">
+ IPsec behind NAT</A></LI>
+<LI><A href="#VPN.masq">VPN masquerade patches</A> to make a Linux NAT
+ box handle IPsec packets correctly</LI>
+</UL>
+<H3><A name="NAT.ref">Other references on NAT and IPsec</A></H3>
+<P>Other documents which may be relevant include:</P>
+<UL>
+<LI>an Internet Draft on<A href="http://search.ietf.org/internet-drafts/draft-aboba-nat-ipsec-04.txt">
+ IPsec and NAT</A> which may eventually evolve into a standard solution
+ for this problem.</LI>
+<LI>an informational<A href="http://www.cis.ohio-state.edu/rfc/rfc2709.txt">
+ RFC</A>,<CITE> Security Model with Tunnel-mode IPsec for NAT Domains</CITE>
+.</LI>
+<LI>an<A href="http://www.cisco.com/warp/public/759/ipj_3-4/ipj_3-4_nat.html">
+ article</A> in Cisco's<CITE> Internet Protocol Journal</CITE></LI>
+</UL>
+<H2><A name="complications">Other complications</A></H2>
+<P>Of course simply allowing UDP 500 and ESP packets is not the whole
+ story. Various other issues arise in making IPsec and packet filters
+ co-exist and even co-operate. Some of them are summarised below.</P>
+<H3><A name="through">IPsec<EM> through</EM></A> the gateway</H3>
+<P>Basic IPsec packet filtering rules deal only with packets addressed
+ to or sent from your IPsec gateway.</P>
+<P>It is a separate policy decision whether to permit such packets to
+ pass through the gateway so that client machines can build end-to-end
+ IPsec tunnels of their own. This may not be practical if you are using<A
+href="#NAT"> NAT (IP masquerade)</A> on your gateway, and may conflict
+ with some corporate security policies.</P>
+<P>Where possible, allowing this is almost certainly a good idea. Using
+ IPsec on an end-to-end basis is more secure than gateway-to-gateway.</P>
+<P>Doing it is quite simple. You just need firewall rules that allow UDP
+ port 500 and protocols 50 and 51 to pass through your gateway. If you
+ wish, you can of course restrict this to certain hosts.</P>
+<H3><A name="ipsec_only">Preventing non-IPsec traffic</A></H3>
+ You can also filter<EM> everything but</EM> UDP port 500 and ESP or AH
+ to restrict traffic to IPsec only, either for anyone communicating with
+ your host or just for specific partners.
+<P>One application of this is for the telecommuter who might have:</P>
+<PRE>     Sunset==========West------------------East ================= firewall --- the Internet
+         home network      untrusted net        corporate network</PRE>
+<P>The subnet on the right is 0.0.0.0/0, the whole Internet. The West
+ gateway is set up so that it allows only IPsec packets to East in or
+ out.</P>
+<P>This configuration is used in AT&amp;T Research's network. For details,
+ see the<A href="#applied"> papers</A> links in our introduction.</P>
+<P>Another application would be to set up firewall rules so that an
+ internal machine, such as an employees-only web server, could not talk
+ to the outside world except via specific IPsec tunnels.</P>
+<H3><A name="unknowngate">Filtering packets from unknown gateways</A></H3>
+<P>It is possible to use firewall rules to restrict UDP 500, ESP and AH
+ packets so that these packets are accepted only from known gateways.
+ This is not strictly necessary since FreeS/WAN will discard packets
+ from unknown gateways. You might, however, want to do it for any of a
+ number of reasons. For example:</P>
+<UL>
+<LI>Arguably, &quot;belt and suspenders&quot; is the sensible approach to
+ security. If you can block a potential attack in two ways, use both.
+ The only question is whether to look for a third way after implementing
+ the first two.</LI>
+<LI>Some admins may prefer to use the firewall code this way because
+ they prefer firewall logging to FreeS/WAN's logging.</LI>
+<LI>You may need it to implement your security policy. Consider an
+ employee working at home, and a policy that says traffic from the home
+ system to the Internet at large must go first via IPsec to the
+ corporate LAN and then out to the Internet via the corporate firewall.
+ One way to do that is to make<VAR> ipsec0</VAR> the default route on
+ the home gateway and provide exceptions only for UDP 500 and ESP to the
+ corporate gateway. Everything else is then routed via the tunnel to the
+ corporate gateway.</LI>
+</UL>
+<P>It is not possible to use only static firewall rules for this
+ filtering if you do not know the other gateways' IP addresses in
+ advance, for example if you have &quot;road warriors&quot; who may connect from a
+ different address each time or if want to do<A href="#carpediem">
+ opportunistic encryption</A> to arbitrary gateways. In these cases, you
+ can accept UDP 500 IKE packets from anywhere, then use the<A href="#updown">
+ updown</A> script feature of<A href="manpage.d/ipsec_pluto.8.html">
+ pluto(8)</A> to dynamically adjust firewalling for each negotiated
+ tunnel.</P>
+<P>Firewall packet filtering does not much reduce the risk of a<A href="#DOS">
+ denial of service attack</A> on FreeS/WAN. The firewall can drop
+ packets from unknown gateways, but KLIPS does that quite efficiently
+ anyway, so you gain little. The firewall cannot drop otherwise
+ legitmate packets that fail KLIPS authentication, so it cannot protect
+ against an attack designed to exhaust resources by making FreeS/WAN
+ perform many expensive authentication operations.</P>
+<P>In summary, firewall filtering of IPsec packets from unknown gateways
+ is possible but not strictly necessary.</P>
+<H2><A name="otherfilter">Other packet filters</A></H2>
+<P>When the IPsec gateway is also acting as your firewall, other packet
+ filtering rules will be in play. In general, those are outside the
+ scope of this document. See our<A href="#firewall.linux"> Linux
+ firewall links</A> for information. There are a few types of packet,
+ however, which can affect the operation of FreeS/WAN or of diagnostic
+ tools commonly used with it. These are discussed below.</P>
+<H3><A name="ICMP">ICMP filtering</A></H3>
+<P><A href="#ICMP.gloss">ICMP</A> is the<STRONG> I</STRONG>nternet<STRONG>
+ C</STRONG>ontrol<STRONG> M</STRONG>essage<STRONG> P</STRONG>rotocol. It
+ is used for messages between IP implementations themselves, whereas IP
+ used is used between the clients of those implementations. ICMP is,
+ unsurprisingly, used for control messages. For example, it is used to
+ notify a sender that a desination is not reachable, or to tell a router
+ to reroute certain packets elsewhere.</P>
+<P>ICMP handling is tricky for firewalls.</P>
+<UL>
+<LI>You definitely want some ICMP messages to get through; things won't
+ work without them. For example, your clients need to know if some
+ destination they ask for is unreachable.</LI>
+<LI>On the other hand, you do equally definitely do not want untrusted
+ folk sending arbitrary control messages to your machines. Imagine what
+ someone moderately clever and moderately malicious could do to you,
+ given control of your network's routing.</LI>
+</UL>
+<P>ICMP does not use ports. Messages are distinguished by a &quot;message
+ type&quot; field and, for some types, by an additional &quot;code&quot; field. The
+ definitive list of types and codes is on the<A href="http://www.iana.org">
+ IANA</A> site.</P>
+<P>One expert uses this definition for ICMP message types to be dropped
+ at the firewall.</P>
+<PRE># ICMP types which lack socially redeeming value.
+#  5     Redirect
+#  9     Router Advertisement
+# 10     Router Selection
+# 15     Information Request
+# 16     Information Reply
+# 17     Address Mask Request
+# 18     Address Mask Reply
+
+badicmp='5 9 10 15 16 17 18'</PRE>
+<P>A more conservative approach would be to make a list of allowed types
+ and drop everything else.</P>
+<P>Whichever way you do it, your ICMP filtering rules on a FreeS/WAN
+ gateway should allow at least the following ICMP packet types:</P>
+<DL>
+<DT>echo (type 8)</DT>
+<DD></DD>
+<DT>echo reply (type 0)</DT>
+<DD>These are used by ping(1). We recommend allowing both types through
+ the tunnel and to or from your gateway's external interface, since
+ ping(1) is an essential testing tool.
+<P>It is fairly common for firewalls to drop ICMP echo packets addressed
+ to machines behind the firewall. If that is your policy, please create
+ an exception for such packets arriving via an IPsec tunnel, at least
+ during intial testing of those tunnels.</P>
+</DD>
+<DT>destination unreachable (type 3)</DT>
+<DD>This is used, with code 4 (Fragmentation Needed and Don't Fragment
+ was Set) in the code field, to control<A href="#pathMTU"> path MTU
+ discovery</A>. Since IPsec processing adds headers, enlarges packets
+ and may cause fragmentation, an IPsec gateway should be able to send
+ and receive these ICMP messages<STRONG> on both inside and outside
+ interfaces</STRONG>.</DD>
+</DL>
+<H3><A name="traceroute">UDP packets for traceroute</A></H3>
+<P>The traceroute(1) utility uses UDP port numbers from 33434 to
+ approximately 33633. Generally, these should be allowed through for
+ troubleshooting.</P>
+<P>Some firewalls drop these packets to prevent outsiders exploring the
+ protected network with traceroute(1). If that is your policy, consider
+ creating an exception for such packets arriving via an IPsec tunnel, at
+ least during intial testing of those tunnels.</P>
+<H3><A name="l2tp">UDP for L2TP</A></H3>
+<P> Windows 2000 does, and products designed for compatibility with it
+ may, build<A href="#l2tp"> L2TP</A> tunnels over IPsec connections.</P>
+<P>For this to work, you must allow UDP protocol 1701 packets coming out
+ of your tunnels to continue to their destination. You can, and probably
+ should, block such packets to or from your external interfaces, but
+ allow them from<VAR> ipsec0</VAR>.</P>
+<P>See also our Windows 2000<A href="interop.html#win2k"> interoperation
+ discussion</A>.</P>
+<H2><A name="packets">How it all works: IPsec packet details</A></H2>
+<P>IPsec uses three main types of packet:</P>
+<DL>
+<DT><A href="#IKE">IKE</A> uses<STRONG> the UDP protocol and port 500</STRONG>
+.</DT>
+<DD>Unless you are using only (less secure, not recommended) manual
+ keying, you need IKE to negotiate connection parameters, acceptable
+ algorithms, key sizes and key setup. IKE handles everything required to
+ set up, rekey, repair or tear down IPsec connections.</DD>
+<DT><A href="#ESP">ESP</A> is<STRONG> protocol number 50</STRONG></DT>
+<DD>This is required for encrypted connections.</DD>
+<DT><A href="#AH">AH</A> is<STRONG> protocol number 51</STRONG></DT>
+<DD>This can be used where only authentication, not encryption, is
+ required.</DD>
+</DL>
+<P>All of those packets should have appropriate IPsec gateway addresses
+ in both the to and from IP header fields. Firewall rules can check this
+ if you wish, though it is not strictly necessary. This is discussed in
+ more detail<A href="#unknowngate"> later</A>.</P>
+<P>IPsec processing of incoming packets authenticates them then removes
+ the ESP or AH header and decrypts if necessary. Successful processing
+ exposes an inner packet which is then delivered back to the firewall
+ machinery, marked as having arrived on an<VAR> ipsec[0-3]</VAR>
+ interface. Firewall rules can use that interface label to distinguish
+ these packets from unencrypted packets which are labelled with the
+ physical interface they arrived on (or perhaps with a non-IPsec virtual
+ interface such as<VAR> ppp0</VAR>).</P>
+<P>One of our users sent a mailing list message with a<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/12/msg00006.html">
+ diagram</A> of the packet flow.</P>
+<H3><A name="noport">ESP and AH do not have ports</A></H3>
+<P>Some protocols, such as TCP and UDP, have the notion of ports. Others
+ protocols, including ESP and AH, do not. Quite a few IPsec newcomers
+ have become confused on this point. There are no ports<EM> in</EM> the
+ ESP or AH protocols, and no ports used<EM> for</EM> them. For these
+ protocols,<EM> the idea of ports is completely irrelevant</EM>.</P>
+<H3><A name="header">Header layout</A></H3>
+<P>The protocol numbers for ESP or AH are used in the 'next header'
+ field of the IP header. On most non-IPsec packets, that field would
+ have one of:</P>
+<UL>
+<LI>1 for ICMP</LI>
+<LI>4 for IP-in-IP encapsulation</LI>
+<LI>6 for TCP</LI>
+<LI>17 for UDP</LI>
+<LI>... or one of about 100 other possibilities listed by<A href="http://www.iana.org">
+ IANA</A></LI>
+</UL>
+<P>Each header in the sequence tells what the next header will be. IPsec
+ adds headers for ESP or AH near the beginning of the sequence. The
+ original headers are kept and the 'next header' fields adjusted so that
+ all headers can be correctly interpreted.</P>
+<P>For example, using<STRONG> [</STRONG><STRONG> ]</STRONG> to indicate
+ data protected by ESP and unintelligible to an eavesdropper between the
+ gateways:</P>
+<UL>
+<LI>a simple packet might have only IP and TCP headers with:
+<UL>
+<LI>IP header says next header --&gt; TCP</LI>
+<LI>TCP header port number --&gt; which process to send data to</LI>
+<LI>data</LI>
+</UL>
+</LI>
+<LI>with ESP<A href="#transport"> transport mode</A> encapsulation, that
+ packet would have:
+<UL>
+<LI>IP header says next header --&gt; ESP</LI>
+<LI>ESP header<STRONG> [</STRONG> says next --&gt; TCP</LI>
+<LI>TCP header port number --&gt; which process to send data to</LI>
+<LI>data<STRONG> ]</STRONG></LI>
+</UL>
+ Note that the IP header is outside ESP protection, visible to an
+ attacker, and that the final destination must be the gateway.</LI>
+<LI>with ESP in<A href="#tunnel"> tunnel mode</A>, we might have:
+<UL>
+<LI>IP header says next header --&gt; ESP</LI>
+<LI>ESP header<STRONG> [</STRONG> says next --&gt; IP</LI>
+<LI>IP header says next header --&gt; TCP</LI>
+<LI>TCP header port number --&gt; which process to send data to</LI>
+<LI>data<STRONG> ]</STRONG></LI>
+</UL>
+ Here the inner IP header is protected by ESP, unreadable by an
+ attacker. Also, the inner header can have a different IP address than
+ the outer IP header, so the decrypted packet can be routed from the
+ IPsec gateway to a final destination which may be another machine.</LI>
+</UL>
+<P>Part of the ESP header itself is encrypted, which is why the<STRONG>
+ [</STRONG> indicating protected data appears in the middle of some
+ lines above. The next header field of the ESP header is protected. This
+ makes<A href="#traffic"> traffic analysis</A> more difficult. The next
+ header field would tell an eavesdropper whether your packet was UDP to
+ the gateway, TCP to the gateway, or encapsulated IP. It is better not
+ to give this information away. A clever attacker may deduce some of it
+ from the pattern of packet sizes and timings, but we need not make it
+ easy.</P>
+<P>IPsec allows various combinations of these to match local policies,
+ including combinations that use both AH and ESP headers or that nest
+ multiple copies of these headers.</P>
+<P>For example, suppose my employer has an IPsec VPN running between two
+ offices so all packets travelling between the gateways for those
+ offices are encrypted. If gateway policies allow it (The admins could
+ block UDP 500 and protocols 50 and 51 to disallow it), I can build an
+ IPsec tunnel from my desktop to a machine in some remote office. Those
+ packets will have one ESP header throughout their life, for my
+ end-to-end tunnel. For part of the route, however, they will also have
+ another ESP layer for the corporate VPN's encapsulation. The whole
+ header scheme for a packet on the Internet might be:</P>
+<UL>
+<LI>IP header (with gateway address) says next header --&gt; ESP</LI>
+<LI>ESP header<STRONG> [</STRONG> says next --&gt; IP</LI>
+<LI>IP header (with receiving machine address) says next header --&gt; ESP</LI>
+<LI>ESP header<STRONG> [</STRONG> says next --&gt; TCP</LI>
+<LI>TCP header port number --&gt; which process to send data to</LI>
+<LI>data<STRONG> ]]</STRONG></LI>
+</UL>
+<P>The first ESP (outermost) header is for the corporate VPN. The inner
+ ESP header is for the secure machine-to-machine link.</P>
+<H3><A name="dhr">DHR on the updown script</A></H3>
+<P>Here are some mailing list comments from<A href="manpage.d/ipsec_pluto.8.html">
+ pluto(8)</A> developer Hugh Redelmeier on an earlier draft of this
+ document:</P>
+<PRE>There are many important things left out
+
+- firewalling is important but must reflect (implement) policy.  Since
+  policy isn't the same for all our customers, and we're not experts,
+  we should concentrate on FW and MASQ interactions with FreeS/WAN.
+
+- we need a diagram to show packet flow WITHIN ONE MACHINE, assuming
+  IKE, IPsec, FW, and MASQ are all done on that machine.  The flow is
+  obvious if the components are run on different machines (trace the
+  cables).
+
+  IKE input:
+        + packet appears on public IF, as UDP port 500
+        + input firewalling rules are applied (may discard)
+        + Pluto sees the packet.
+
+  IKE output:
+        + Pluto generates the packet &amp; writes to public IF, UDP port 500
+        + output firewalling rules are applied (may discard)
+        + packet sent out public IF
+
+  IPsec input, with encapsulated packet, outer destination of this host:
+        + packet appears on public IF, protocol 50 or 51.  If this
+          packet is the result of decapsulation, it will appear
+          instead on the paired ipsec IF.
+        + input firewalling rules are applied (but packet is opaque)
+        + KLIPS decapsulates it, writes result to paired ipsec IF
+        + input firewalling rules are applied to resulting packet
+          as input on ipsec IF
+        + if the destination of the packet is this machine, the
+          packet is passed on to the appropriate protocol handler.
+          If the original packet was encapsulated more than once
+          and the new outer destination is this machine, that
+          handler will be KLIPS.
+        + otherwise:
+          * routing is done for the resulting packet.  This may well
+            direct it into KLIPS for encoding or encrypting.  What
+            happens then is described elsewhere.
+          * forwarding firewalling rules are applied
+          * output firewalling rules are applied
+          * the packet is sent where routing specified
+
+ IPsec input, with encapsulated packet, outer destination of another host:
+        + packet appears on some IF, protocol 50 or 51
+        + input firewalling rules are applied (but packet is opaque)
+        + routing selects where to send the packet
+        + forwarding firewalling rules are applied (but packet is opaque)
+        + packet forwarded, still encapsulated
+
+  IPsec output, from this host or from a client:
+        + if from a client, input firewalling rules are applied as the
+          packet arrives on the private IF
+        + routing directs the packet to an ipsec IF (this is how the
+          system decides KLIPS processing is required)
+        + if from a client, forwarding firewalling rules are applied
+        + KLIPS eroute mechanism matches the source and destination
+          to registered eroutes, yielding a SPI group.  This dictates
+          processing, and where the resulting packet is to be sent
+          (the destinations SG and the nexthop).
+        + output firewalling is not applied to the resulting
+          encapsulated packet
+
+- Until quite recently, KLIPS would double encapsulate packets that
+  didn't strictly need to be.  Firewalling should be prepared for
+  those packets showing up as ESP and AH protocol input packets on
+  an ipsec IF.
+
+- MASQ processing seems to be done as if it were part of the
+  forwarding firewall processing (this should be verified).
+
+- If a firewall is being used, it is likely the case that it needs to
+  be adjusted whenever IPsec SAs are added or removed.  Pluto invokes
+  a script to do this (and to adjust routing) at suitable times.  The
+  default script is only suitable for ipfwadm-managed firewalls.  Under
+  LINUX 2.2.x kernels, ipchains can be managed by ipfwadm (emulation),
+  but ipchains more powerful if manipulated using the ipchains command.
+  In this case, a custom updown script must be used.
+
+  We think that the flexibility of ipchains precludes us supplying an
+  updown script that would be widely appropriate.</PRE>
+<HR>
+<H1><A NAME="trouble"></A>Linux FreeS/WAN Troubleshooting Guide</H1>
+<H2><A NAME="overview"></A>Overview</H2>
+<P> This document covers several general places where you might have a
+ problem:</P>
+<OL>
+<LI><A HREF="#install">During install</A>.</LI>
+<LI><A HREF="#negotiation">During the negotiation process</A>.</LI>
+<LI><A HREF="#use">Using an established connection</A>.</LI>
+</OL>
+<P>This document also contains<A HREF="#notes"> notes</A> which expand
+ on points made in these sections, and tips for<A HREF="#prob.report">
+ problem reporting</A>. If the other end of your connection is not
+ FreeS/WAN, you'll also want to read our<A HREF="interop.html#interop.problem">
+ interoperation</A> document.</P>
+<H2><A NAME="install"></A>1. During Install</H2>
+<H3><A NAME="8_2_1">1.1 RPM install gotchas</A></H3>
+<P>With the RPM method:</P>
+<UL>
+<LI>Be sure you have installed both the userland tools and the kernel
+ components. One will not work without the other. For example, when
+ using FreeS/WAN-produced RPMs for our 2.04 release, you need both:
+<PRE>    freeswan-userland-2.04_2.4.20_20.9-0.i386.rpm
+    freeswan-module-2.04_2.4.20_20.9-0.i386.rpm
+</PRE>
+</LI>
+</UL>
+<H3><A NAME="8_2_2">1.2 Problems installing from source</A></H3>
+<P>When installing from source, you may find these problems:</P>
+<UL>
+<LI>Missing library. See<A HREF="#gmp.h_missing"> this</A> FAQ.</LI>
+<LI>Missing utilities required for compile. See this<A HREF="install.html#tool.lib">
+ checklist</A>.</LI>
+<LI>Kernel version incompatibility. See<A HREF="#k.versions"> this</A>
+ FAQ.</LI>
+<LI>Another compile problem. Find information in the out.* files, ie.
+ out.kpatch, out.kbuild, created at compile time in the top-level Linux
+ FreeS/WAN directory. Error messages generated by KLIPS during the boot
+ sequence are accessible with the<VAR> dmesg</VAR> command.
+<BR> Check the list archives and the List in Brief to see if this is a
+ known issue. If it is not, report it to the bugs list as described in
+ our<A HREF="#prob.report"> problem reporting</A> section. In some
+ cases, you may be asked to provide debugging information using gdb;
+ details<A HREF="#gdb"> below</A>.</LI>
+<LI>If your kernel compiles but you fail to install your new
+ FreeS/WAN-enabled kernel, review the sections on<A HREF="install.html#newk">
+ installing the patched kernel</A>, and<A HREF="#testinstall"> testing</A>
+ to see if install succeeded.</LI>
+</UL>
+<H3><A NAME="install.check"></A>1.3 Install checks</H3>
+<P><VAR>ipsec verify</VAR> checks a number of FreeS/WAN essentials. Here
+ are some hints on what do to when your system doesn't check out:</P>
+<P></P>
+<TABLE border="1">
+<TR><TD><STRONG>Problem</STRONG></TD><TD><STRONG>Status</STRONG></TD><TD>
+<STRONG>Action</STRONG></TD></TR>
+<TR><TD><VAR>ipsec</VAR> not on-path</TD><TD>&nbsp;</TD><TD>
+<P>Add<VAR> /usr/local/sbin</VAR> to your PATH.</P>
+</TD></TR>
+<TR><TD>Missing KLIPS support</TD><TD><FONT COLOR="#FF0000">critical</FONT>
+</TD><TD>See<A HREF="#noKLIPS"> this FAQ.</A></TD></TR>
+<TR><TD>No RSA private key</TD><TD>&nbsp;</TD><TD>
+<P>Follow<A HREF="install.html#genrsakey"> these instructions</A> to
+ create an RSA key pair for your host. RSA keys are:</P>
+<UL>
+<LI>required for opportunistic encryption, and</LI>
+<LI>our preferred method to authenticate pre-configured connections.</LI>
+</UL>
+</TD></TR>
+<TR><TD><VAR>pluto</VAR> not running</TD><TD><FONT COLOR="#FF0000">
+critical</FONT></TD><TD>
+<PRE>service ipsec start</PRE>
+</TD></TR>
+<TR><TD>No port 500 hole</TD><TD><FONT COLOR="#FF0000">critical</FONT></TD><TD>
+Open port 500 for IKE negotiation.</TD></TR>
+<TR><TD>Port 500 check N/A</TD><TD>&nbsp;</TD><TD>Check that port 500 is open
+ for IKE negotiation.</TD></TR>
+<TR><TD>Failed DNS checks</TD><TD>&nbsp;</TD><TD>Opportunistic encryption
+ requires information from DNS. To set this up, see<A HREF="#opp.setup">
+ our instructions</A>.</TD></TR>
+<TR><TD>No public IP address</TD><TD>&nbsp;</TD><TD>Check that the interface
+ which you want to protect with IPSec is up and running.</TD></TR>
+</TABLE>
+<H3><A NAME="oe.trouble"></A>1.3 Troubleshooting OE</H3>
+<P>OE should work with no local configuration, if you have posted DNS
+ TXT records according to the instructions in our<A HREF="quickstart.html">
+ quickstart guide</A>. If you encounter trouble, try these hints. We
+ welcome additional hints via the<A HREF="mail.html"> users' mailing
+ list</A>.</P>
+<TABLE border="1">
+<TR><TD><STRONG>Symptom</STRONG></TD><TD><STRONG>Problem</STRONG></TD><TD>
+<STRONG>Action</STRONG></TD></TR>
+<TR><TD> You're running FreeS/WAN 2.01 (or later), and initiating a
+ connection to FreeS/WAN 2.00 (or earlier). In your logs, you see a
+ message like:
+<PRE>no RSA public key known for '192.0.2.13';
+DNS search for KEY failed (no KEY record
+for 13.2.0.192.in-addr.arpa.)</PRE>
+ The older FreeS/WAN logs no error.</TD><TD><A NAME="oe.trouble.flagday">
+</A> A protocol level incompatibility between 2.01 (or later) and 2.00
+ (or earlier) causes this error. It occurs when a FreeS/WAN 2.01 (or
+ later) box for which no KEY record is posted attempts to initiate an OE
+ connection to older FreeS/WAN versions (2.00 and earlier). Note that
+ older versions can initiate to newer versions without this error.</TD><TD>
+If you control the peer host, upgrade its FreeS/WAN to 2.01 (or later),
+ and post new style TXT records for it. If not, but if you know its
+ sysadmin, perhaps a quick note is in order. If neither option is
+ possible, you can ease the transition by posting an old style KEY
+ record (created with a command like &quot;ipsec&nbsp;showhostkey&nbsp;--key&quot;) to the
+ reverse map for the FreeS/WAN 2.01 (or later) box.</TD></TR>
+<TR><TD>OE host is very slow to contact other hosts.</TD><TD>Slow DNS
+ service while running OE.</TD><TD>It's a good idea to run a caching DNS
+ server on your OE host, as outlined in<A HREF="http://lists.freeswan.org/pipermail/design/2003-January/004205.html">
+ this mailing list message</A>. If your DNS servers are elsewhere, put
+ their IPs in the<VAR> clear</VAR> policy group, and re-read groups with
+<PRE>ipsec auto --rereadgroups</PRE>
+</TD></TR>
+<TR><TD>
+<PRE>Can't Opportunistically initiate for
+192.0.2.2 to 192.0.2.3: no TXT record
+for 13.2.0.192.in-addr.arpa.</PRE>
+</TD><TD>Peer is not set up for OE.</TD><TD>
+<P>None. Plenty of hosts on the Internet do not run OE. If, however, you
+ have set OE up on that peer, this may indicate that you need to wait up
+ to 48 hours for its DNS records to propagate.</P>
+</TD></TR>
+<TR><TD><VAR>ipsec verify</VAR> does not find DNS records:
+<PRE>...
+Looking for TXT in forward map:
+                xy.example.com...[FAILED]
+Looking for TXT in reverse map...[FAILED]
+...</PRE>
+ You also experience authentication failure:
+<BR>
+<PRE>Possible authentication failure:
+no acceptable response to our
+first encrypted message</PRE>
+</TD><TD>DNS records are not posted or have not propagated.</TD><TD>Did
+ you post the DNS records necessary for OE? If not, do so using the
+ instructions in our<A HREF="#quickstart"> quickstart guide</A>. If so,
+ wait up to 48 hours for the DNS records to propagate.</TD></TR>
+<TR><TD><VAR>ipsec verify</VAR> does not find DNS records, and you
+ experience authentication failure.</TD><TD>For iOE, your ID does not
+ match location of forward DNS record.</TD><TD>In<VAR> config setup</VAR>
+, change<VAR> myid=</VAR> to match the forward DNS where you posted the
+ record. Restart FreeS/WAN. For reference, see our<A HREF="#opp.client">
+ iOE instructions</A>.</TD></TR>
+<TR><TD><VAR>ipsec verify</VAR> finds DNS records, yet there is still
+ authentication failure. ( ? )</TD><TD>DNS records are malformed.</TD><TD>
+Re-create the records and send new copies to your DNS administrator.</TD>
+</TR>
+<TR><TD><VAR>ipsec verify</VAR> finds DNS records, yet there is still
+ authentication failure. ( ? )</TD><TD>DNS records show different keys
+ for a gateway vs. its subnet hosts.</TD><TD>All TXT records for boxes
+ protected by an OE gateway must contain the gateway's public key.
+ Re-create and re-post any incorrect records using<A HREF="#opp.incoming">
+ these instructions</A>.</TD></TR>
+<TR><TD>OE gateway loses connectivity to its subnet. The gateway's
+ routing table shows routes to the subnet through IPsec interfaces.</TD><TD>
+The subnet is part of the<VAR> private</VAR> or<VAR> block</VAR> policy
+ group on the gateway.</TD><TD>Remove the subnet from the group, and
+ reread groups with
+<PRE>ipsec auto --rereadgroups</PRE>
+</TD></TR>
+<TR><TD>OE does not work to hosts on the local LAN.</TD><TD>This is a
+ known issue.</TD><TD>See<A HREF="opportunism.known-issues"> this list</A>
+ of known issues with OE.</TD></TR>
+<TR><TD>FreeS/WAN does not seem to be executing your default policy. In
+ your logs, you see a message like:
+<PRE>/etc/ipsec.d/policies/iprivate-or-clear&quot;
+line 14: subnet &quot;0.0.0.0/0&quot;,
+source 192.0.2.13/32,
+already &quot;private-or-clear&quot;</PRE>
+</TD><TD><A HREF="#fullnet">Fullnet</A> in a policy group file defines
+ your default policy. Fullnet should normally be present in only one
+ policy group file. The fine print: you can have two default policies
+ defined so long as they protect different local endpoints (e.g. the
+ FreeS/WAN gateway and a subnet).</TD><TD> Find all policies which
+ contain fullnet with:
+<BR>
+<PRE>grep -F 0.0.0.0/0 /etc/ipsec.d/policies/*</PRE>
+ then remove the unwanted occurrence(s).</TD></TR>
+</TABLE>
+<H2><A NAME="negotiation"></A>2. During Negotiation</H2>
+<P>When you fail to bring up a tunnel, you'll need to find out:</P>
+<UL>
+<LI><A HREF="#state">what your connection state is,</A> and often</LI>
+<LI><A HREF="#find.pluto.error">an error message</A>.</LI>
+</UL>
+<P>before you can<A HREF="#interpret.pluto.error"> diagnose your problem</A>
+.</P>
+<H3><A NAME="state"></A>2.1 Determine Connection State</H3>
+<H4><A NAME="8_3_1_1">Finding current state</A></H4>
+<P>You can see connection states (STATE_MAIN_I1 and so on) when you
+ bring up a connection on the command line. If you have missed this, or
+ brought up your connection automatically, use:</P>
+<PRE>ipsec auto --status</PRE>
+<P>The most relevant state is the last one reached.</P>
+<H4><A NAME="8_3_1_2"><VAR>What's this supposed to look like?</VAR></A></H4>
+<P>Negotiations should proceed though various states, in the processes
+ of:</P>
+<OL>
+<LI>IKE negotiations (aka Phase 1, Main Mode, STATE_MAIN_*)</LI>
+<LI>IPSEC negotiations (aka Phase 2, Quick Mode, STATE_QUICK_*)</LI>
+</OL>
+<P>These are done and a connection is established when you see messages
+ like:</P>
+<PRE>    000 #21: &quot;myconn&quot; STATE_MAIN_I4 (ISAKMP SA established)...
+    000 #2: &quot;myconn&quot; STATE_QUICK_I2 (sent QI2, IPsec SA established)...</PRE>
+<P> Look for the key phrases are &quot;ISAKMP SA established&quot; and &quot;IPSec SA
+ established&quot;, with the relevant connection name. Often, this happens at
+ STATE_MAIN_I4 and STATE_QUICK_I2, respectively.</P>
+<P><VAR>ipsec auto --status</VAR> will tell you what states<STRONG> have
+ been achieved</STRONG>, rather than the current state. Since
+ determining the current state is rather more difficult to do, current
+ state information is not available from Linux FreeS/WAN. If you are
+ actively bringing a connection up, the status report's last states for
+ that connection likely reflect its current state. Beware, though, of
+ the case where a connection was correctly brought up but is now downed:
+ Linux FreeS/WAN will not notice this until it attempts to rekey.
+ Meanwhile, the last known state indicates that the connection has been
+ established.</P>
+<P>If your connection is stuck at STATE_MAIN_I1, skip straight to<A HREF="#ikepath">
+ here</A>.</P>
+<H3><A NAME="find.pluto.error"></A>2.2 Finding error text</H3>
+<P>Solving most errors will require you to find verbose error text,
+ either on the command line or in the logs.</P>
+<H4><A NAME="8_3_2_1">Verbose start for more information</A></H4>
+<P> Note that you can get more detail from<VAR> ipsec auto</VAR> using
+ the --verbose flag:</P>
+<PRE STYLE="margin-bottom: 0.2in">    ipsec auto --verbose --up west-east</PRE>
+<P> More complete information can be gleaned from the<A HREF="#logusage">
+ log files</A>.</P>
+<H4><A NAME="8_3_2_2">Debug levels count</A></H4>
+<P>The amount of description you'll get here depends on ipsec.conf debug
+ settings,<VAR> klipsdebug</VAR>= and<VAR> plutodebug</VAR>=. When
+ troubleshooting, set at least one of these to<VAR> all</VAR>, and when
+ done, reset it to<VAR> none</VAR> so your logs don't fill up. Note that
+ you must have enabled the<VAR> klipsdebug</VAR><A HREF="install.html#allbut">
+ compile-time option</A> for the<VAR> klipsdebug</VAR> configuration
+ switch to work.</P>
+<P>For negotiation problems<VAR> plutodebug</VAR> is most relevant.<VAR>
+ klipsdebug</VAR> applies mainly to attempts to use an
+ already-established connection. See also<A HREF="#parts"> this</A>
+ description of the division of duties within Linux FreeS/WAN.</P>
+<P>After raising your debug levels, restart Linux FreeS/WAN to ensure
+ that ipsec.conf is reread, then recreate the error to generate verbose
+ logs.</P>
+<H4><A NAME="8_3_2_3"><VAR>ipsec barf</VAR> for lots of debugging
+ information</A></H4>
+<P><A HREF="manpage.d/ipsec_barf.8.html"><VAR> ipsec barf (8)</VAR></A>
+ collects a bunch of useful debugging information, including these logs
+ Use the command</P>
+<PRE>
+    ipsec barf &gt; barf.west
+</PRE>
+<P>to generate one.</P>
+<H4><A NAME="8_3_2_4">Find the error</A></H4>
+<P>Search out the failure point in your logs. Are there a handful of
+ lines which succinctly describe how things are going wrong or contrary
+ to your expectation? Sometimes the failure point is not immediately
+ obvious: Linux FreeS/WAN's errors are usually not marked &quot;Error&quot;. Have
+ a look in the<A HREF="faq.html"> FAQ</A> for what some common failures
+ look like.</P>
+<P>Tip: problems snowball. Focus your efforts on the first problem,
+ which is likely to be the cause of later errors.</P>
+<H4><A NAME="8_3_2_5">Play both sides</A></H4>
+<P>Also find error text on the peer IPSec box. This gives you two
+ perspectives on the same failure.</P>
+<P>At times you will require information which only one side has. The
+ peer can merely indicate the presence of an error, and its approximate
+ point in the negotiations. If one side keeps retrying, it may be
+ because there is a show stopper on the other side. Have a look at the
+ other side and figure out what it doesn't like.</P>
+<P>If the other end is not Linux FreeS/WAN, the principle is the same:
+ replicate the error with its most verbose logging on, and capture the
+ output to a file.</P>
+<H3><A NAME="interpret.pluto.error"></A>2.3 Interpreting a Negotiation
+ Error</H3>
+<H4><A NAME="ikepath"></A>Connection stuck at STATE_MAIN_I1</H4>
+<P>This error commonly happens because IKE (port 500) packets, needed to
+ negotiate an IPSec connection, cannot travel freely between your IPSec
+ gateways. See<A HREF="#packets"> our firewall document</A> for details.</P>
+<H4><A NAME="8_3_3_2">Other errors</A></H4>
+<P>Other errors require a bit more digging. Use the following resources:</P>
+<UL>
+<LI><A HREF="faq.html">the FAQ</A> . Since this document is constantly
+ updated, the snapshot's FAQ may have a new entry relevant to your
+ problem.</LI>
+<LI>our<A HREF="background.html"> background document</A> . Special
+ considerations which, while not central to Linux FreeS/WAN, are often
+ tripped over. Includes problems with<A href="#MTU.trouble"> packet
+ fragmentation</A>, and considerations for testing opportunism.</LI>
+<LI>the<A HREF="#lists"> list archives</A>. Each of the searchable
+ archives works differently, so it's worth checking each. Use a search
+ term which is generic, but identifies your error, for example &quot;No
+ connection is known for&quot;.
+<BR> Often, you will find that your question has been answered in the
+ past. Finding an archived answer is quicker than asking the list. You
+ may, however, find similar questions without answers. If you do, send
+ their URLs to the list with your trouble report. The additional
+ examples may help the list tech support person find your answer.</LI>
+<LI>Look into the code where the error is being generated. The pluto
+ code is nicely documented with comments and meaningful variable names.</LI>
+</UL>
+<P>If you have failed to solve your problem with the help of these
+ resources, send a detailed problem report to the users list, following
+ these<A HREF="#prob.report"> guidelines</A>.</P>
+<H2><A NAME="use"></A>3. Using a Connection</H2>
+<H3><A NAME="8_4_1">3.1 Orienting yourself</A></H3>
+<H4><A NAME="8_4_1_1"><VAR>How do I know if it works?</VAR></A></H4>
+<P>Test your connection by sending packets through it. The simplest way
+ to do this is with ping, but the ping needs to<STRONG> test the correct
+ tunnel.</STRONG> See<A HREF="#testgates"> this example scenario</A> if
+ you don't understand this.</P>
+<P></P>
+<P>If your ping returns, test any other connections you've brought u all
+ check out, great. You may wish to<A HREF="#bigpacket"> test with large
+ packets</A> for MTU problems.</P>
+<H4><A NAME="8_4_1_2"><VAR>ipsec barf</VAR> is useful again</A></H4>
+<P>If your ping fails to return, generate an ipsec barf debugging report
+ on each IPSec gateway. On a non-Linux FreeS/WAN implementation, gather
+ equivalent information. Use this, and the tips in the next sections, to
+ troubleshoot. Are you sure that both endpoints are capable of hearing
+ and responding to ping?</P>
+<H3><A NAME="8_4_2">3.2 Those pesky configuration errors</A></H3>
+<P>IPSec may be dropping your ping packets since they do not belong in
+ the tunnels you have constructed:</P>
+<UL>
+<LI>Your ping may not test the tunnel you intend to test. For details,
+ see our<A HREF="#cantping"> &quot;I can't ping&quot;</A> FAQ.</LI>
+<LI> Alternately, you may have a configuration error. For example, you
+ may have configured one of the four possible tunnels between two
+ gateways, but not the one required to secure the important traffic
+ you're now testing. In this case, add and start the tunnel, and try
+ again.</LI>
+</UL>
+<P>In either case, you will often see a message like:</P>
+<PRE>klipsdebug... no eroute</PRE>
+<P>which we discuss in<A HREF="#no_eroute"> this FAQ</A>.</P>
+<P>Note:</P>
+<UL>
+<LI><A HREF="#NAT.gloss">Network Address Translation (NAT)</A> and<A HREF="#masq">
+ IP masquerade</A> may have an effect on which tunnels you need to
+ configure.</LI>
+<LI>When testing a tunnel that protects a multi-node subnet, try several
+ subnet nodes as ping targets, in case one node is routing incorrectly.</LI>
+</UL>
+<H3><A NAME="route.firewall"></A>3.3 Check Routing and Firewalling</H3>
+<P>If you've confirmed your configuration assumptions, the problem is
+ almost certainly with routing or firewalling. Isolate the problem using
+ interface statistics, firewall statistics, or a packet sniffer.</P>
+<H4><A NAME="8_4_3_1">Background:</A></H4>
+<UL>
+<LI>Linux FreeS/WAN supplies all the special routing it needs; you need
+ only route packets out through your IPSec gateway. Verify that on the<VAR>
+ subnetted</VAR> machines you are using for your ping-test, your routing
+ is as expected. I have seen a tunnel &quot;fail&quot; because the subnet machine
+ sending packets out an alternate gateway (not our IPSec gateway) on
+ their return path.</LI>
+<LI>Linux FreeS/WAN requires particular<A HREF="firewall.html">
+ firewalling considerations</A>. Check the firewall rules on your IPSec
+ gateways and ensure that they allow IPSec traffic through. Be sure that
+ no other machine - for example a router between the gateways - is
+ blocking your IPSec packets.</LI>
+</UL>
+<H4><A NAME="ifconfig"></A>View Interface and Firewall Statistics</H4>
+<P>Interface reports and firewall statistics can help you track down
+ lost packets at a glance. Check any firewall statistics you may be
+ keeping on your IPSec gateways, for dropped packets.</P>
+<P><STRONG>Tip</STRONG>: You can take a snapshot of the packets
+ processed by your firewall with:</P>
+<PRE>    iptables -L -n -v</PRE>
+<P>You can get creative with &quot;diff&quot; to find out what happens to a
+ particular packet during transmission.</P>
+<P>Both<VAR> cat /proc/net/dev</VAR> and<VAR> ifconfig</VAR> display
+ interface statistics, and both are included in<VAR> ipsec barf</VAR>.
+ Use either to check if any interface has dropped packets. If you find
+ that one has, test whether this is related to your ping. While you ping
+ continuously, print that interface's statistics several times. Does its
+ drop count increase in proportion to the ping? If so, check why the
+ packets are dropped there.</P>
+<P>To do this, look at the firewall rules that apply to that interface.
+ If the interface is an IPSec interface, more information may be
+ available in the log. Grep for the word &quot;drop&quot; in a log which was
+ created with<VAR> klipsdebug=all</VAR> as the error happened.</P>
+<P>See also this<A HREF="#ifconfig1"> discussion</A> on interpreting<VAR>
+ ifconfig</VAR> statistics.</P>
+<H3><A NAME="sniff"></A>3.4 When in doubt, sniff it out</H3>
+<P>If you have checked configuration assumptions, routing, and firewall
+ rules, and your interface statistics yield no clue, it remains for you
+ to investigate the mystery of the lost packet by the most thorough
+ method: with a packet sniffer (providing, of course, that this is legal
+ where you are working).</P>
+<P>In order to detect packets on the ipsec virtual interfaces, you will
+ need an up-to-date sniffer (tcpdump, ethereal, ksnuffle) on your IPSec
+ gateway machines. You may also find it useful to sniff the ping
+ endpoints.</P>
+<H4><A NAME="8_4_4_1">Anticipate your packets' path</A></H4>
+<P>Ping, and examine each interface along the projected path, checking
+ for your ping's arrival. If it doesn't get to the the next stop, you
+ have narrowed down where to look for it. In this way, you can isolate a
+ problem area, and narrow your troubleshooting focus.</P>
+<P>Within a machine running Linux FreeS/WAN, this<A HREF="#packets">
+ packet flow diagram</A> will help you anticipate a packet's path.</P>
+<P>Note that:</P>
+<UL>
+<LI> from the perspective of the tunneled packet, the entire tunnel is
+ one hop. That's explained in<A HREF="#no_trace"> this</A> FAQ.</LI>
+<LI> an encapsulated IPSec packet will look different, when sniffed,
+ from the plaintext packet which generated it. You can see plaintext
+ packets entering an IPSec interface and the resulting cyphertext
+ packets as they emerge from the corresponding physical interface.</LI>
+</UL>
+<P>Once you isolate where the packet is lost, take a closer look at
+ firewall rules, routing and configuration assumptions as they affect
+ that specific area. If the packet is lost on an IPSec gateway, comb
+ through<VAR> klipsdebug</VAR> output for anomalies.</P>
+<P>If the packet goes through both gateways successfully and reaches the
+ ping target, but does not return, suspect routing. Check that the ping
+ target routes packets back to the IPSec gateway.</P>
+<H3><A NAME="find.use.error"></A>3.5 Check your logs</H3>
+<P>Here, too, log information can be useful. Start with the<A HREF="#find.pluto.error">
+ guidelines above</A>.</P>
+<P>For connection use problems, set<VAR> klipsdebug=all</VAR>. Note that
+ you must have enabled the<VAR> klipsdebug</VAR><A HREF="install.html#allbut">
+ compile-time option</A> to do this. Restart Linux FreeS/WAN so that it
+ rereads<VAR> ipsec.conf</VAR>, then recreate the error condition. When
+ searching through<VAR> klipsdebug</VAR> data, look especially for the
+ keywords &quot;drop&quot; (as in dropped packets) and &quot;error&quot;.</P>
+<P>Often the problem with connection use is not software error, but
+ rather that the software is behaving contrary to expectation.</P>
+<H4><A NAME="interpret.use.error"></A>Interpreting log text</H4>
+<P>To interpret the Linux FreeS/WAN log text you've found, use the same
+ resources as indicated for troubleshooting connection negotiation:<A HREF="faq.html">
+ the FAQ</A> , our<A HREF="background.html"> background document</A>,
+ and the<A HREF="#lists"> list archives</A>. Looking in the KLIPS code
+ is only for the very brave.</P>
+<P>If you are still stuck, send a<A HREF="#prob.report"> detailed
+ problem report</A> to the users' list.</P>
+<H3><A NAME="bigpacket"></A>3.6 More testing for the truly thorough</H3>
+<H4><A NAME="8_4_6_1">Large Packets</A></H4>
+<P>If each of your connections passed the ping test, you may wish to
+ test by pinging with large packets (2000 bytes or larger). If it does
+ not return, suspect MTU issues, and see this<A HREF="#MTU.trouble">
+ discussion</A>.</P>
+<H4><A NAME="8_4_6_2">Stress Tests</A></H4>
+<P>In most users' view, a simple ping test, and perhaps a large-packet
+ ping test suffice to indicate a working IPSec connection.</P>
+<P>Some people might like to do additional stress tests prior to
+ production use. They may be interested in this<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/12/msg00224.html">
+ testing protocol</A> we use at interoperation conferences, aka
+ &quot;bakeoffs&quot;. We also have a<VAR> testing</VAR> directory that ships with
+ the release.</P>
+<H2><A NAME="prob.report"></A>4. Problem Reporting</H2>
+<H3><A NAME="8_5_1">4.1 How to ask for help</A></H3>
+<P>Ask for troubleshooting help on the users' mailing list,<A HREF="mailto:users@lists.freeswan.org">
+ users@lists.freeswan.org</A>. While sometimes an initial query with a
+ quick description of your intent and error will twig someone's memory
+ of a similar problem, it's often necessary to send a second mail with a
+ complete problem report.</P>
+<P>When reporting problems to the mailing list(s), please include:</P>
+<UL>
+<LI>a brief description of the problem</LI>
+<LI>if it's a compile problem, the actual output from make, showing the
+ problem. Try to edit it down to only the relevant part, but when in
+ doubt, be as complete as you can. If it's a kernel compile problem, any
+ relevant out.* files</LI>
+<LI>if it's a run-time problem, pointers to where we can find the
+ complete output from &quot;ipsec barf&quot; from BOTH ENDS (not just one of
+ them). Remember that it's common outside the US and Canada to pay for
+ download volume, so if you can't post barfs on the web and send the URL
+ to the mailing list, at least compress them with tar or gzip.
+<BR> If you can, try to simplify the case that is causing the problem.
+ In particular, if you clear your logs, start FreeS/WAN with no other
+ connections running, cause the problem to happen, and then do<VAR>
+ ipsec barf</VAR> on both ends immediately, that gives the smallest and
+ least cluttered output.</LI>
+<LI>any other error messages, complaints, etc. that you saw. Please send
+ the complete text of the messages, not just a summary.</LI>
+<LI>what your network setup is. Include subnets, gateway addresses, etc.
+ A schematic diagram is a good format for this information.</LI>
+<LI>exactly what you were trying to do with Linux FreeS/WAN, and exactly
+ what went wrong</LI>
+<LI>a fix, if you have one. But remember, you are sending mail to people
+ all over the world; US residents and US citizens in particular, please
+ read doc/exportlaws.html before sending code -- even small bug fixes --
+ to the list or to us.</LI>
+<LI>When in doubt about whether to include some seemingly-trivial item
+ of information, include it. It is rare for problem reports to have too
+ much information, and common for them to have too little.</LI>
+</UL>
+<P>Here are some good general guidelines on bug reporting:<A href="http://tuxedo.org/~esr/faqs/smart-questions.html">
+ How To Ask Questions The Smart Way</A> and<A href="http://www.chiark.greenend.org.uk/~sgtatham/bugs.html">
+ How to Report Bugs Effectively</A>.</P>
+<H3><A NAME="8_5_2">4.2 Where to ask</A></H3>
+<P>To report a problem, send mail about it to the users' list. If you
+ are certain that you have found a bug, report it to the bugs list. If
+ you encounter a problem while doing your own coding on the Linux
+ FreeS/WAN codebase and think it is of interest to the design team,
+ notify the design list. When in doubt, default to the users' list. More
+ information about the mailing lists is found<A HREF="#lists"> here</A>.</P>
+<P>For a number of reasons -- including export-control regulations
+ affecting almost any<STRONG> private</STRONG> discussion of encryption
+ software -- we prefer that problem reports and discussions go to the
+ lists, not directly to the team. Beware that the list goes worldwide;
+ US citizens, read this important information about your<A HREF="#exlaw">
+ export laws</A>. If you're using this software, you really should be on
+ the lists. To get onto them, visit<A HREF="http://lists.freeswan.org/">
+ lists.freeswan.org</A>.</P>
+<P>If you do send private mail to our coders or want a private reply
+ from them, please make sure that the return address on your mail (From
+ or Reply-To header) is a valid one. They have more important things to
+ do than to unravel addresses that have been mangled in an attempt to
+ confuse spammers.</P>
+<H2><A NAME="notes"></A>5. Additional Notes on Troubleshooting</H2>
+<P>The following sections supplement the Guide:<A HREF="#system.info">
+ information available on your system</A>;<A HREF="#testgates"> testing
+ between security gateways</A>;<A HREF="#ifconfig1"> ifconfig reports
+ for KLIPS debugging</A>;<A HREF="#gdb"> using GDB on Pluto</A>.</P>
+<H3><A NAME="system.info"></A>5.1 Information available on your system</H3>
+<H4><A NAME="logusage"></A>Logs used</H4>
+<P>Linux FreeS/WAN logs to:</P>
+<UL>
+<LI>/var/log/secure (or, on Debian, /var/log/auth.log)</LI>
+<LI>/var/log/messages</LI>
+</UL>
+<P>Check both places to get full information. If you find nothing, check
+ your<VAR> syslogd.conf(5)</VAR> to see where your /etc/syslog.conf or
+ equivalent is directing<VAR> authpriv</VAR> messages.</P>
+<H4><A NAME="pages"></A>man pages provided</H4>
+<DL>
+<DT><A HREF="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</A></DT>
+<DD> Manual page for IPSEC configuration file.</DD>
+<DT><A HREF="manpage.d/ipsec.8.html"> ipsec(8)</A></DT>
+<DD STYLE="margin-bottom: 0.2in"> Primary man page for ipsec utilities.</DD>
+</DL>
+<P> Other man pages are on<A HREF="manpages.html"> this list</A> and in</P>
+<UL>
+<LI>/usr/local/man/man3</LI>
+<LI>/usr/local/man/man5</LI>
+<LI>/usr/local/man/man8/ipsec_*</LI>
+</UL>
+<H4><A NAME="statusinfo"></A>Status information</H4>
+<DL>
+<DT>ipsec auto --status</DT>
+<DD> Command to get status report from running system. Displays Pluto's
+ state. Includes the list of connections which are currently &quot;added&quot; to
+ Pluto's internal database; lists state objects reflecting ISAKMP and
+ IPsec SAs being negotiated or installed.</DD>
+<DT> ipsec look</DT>
+<DD> Brief status info.</DD>
+<DT> ipsec barf</DT>
+<DD STYLE="margin-bottom: 0.2in"> Copious debugging info.</DD>
+</DL>
+<H3><A NAME="testgates"></A> 5.2 Testing between security gateways</H3>
+<P>Sometimes you need to test a subnet-subnet tunnel. This is a tunnel
+ between two security gateways, which protects traffic on behalf of the
+ subnets behind these gateways. On this network:</P>
+<PRE>     Sunset==========West------------------East=========Sunrise
+                     IPSec gateway         IPSec gateway
+           local net       untrusted net       local net</PRE>
+<P> you might name this tunnel sunset-sunrise. You can test this tunnel
+ by having a machine behind one gateway ping a machine behind the other
+ gateway, but this is not always convenient or even possible.</P>
+<P>Simply pinging one gateway from the other is not useful. Such a ping
+ does not normally go through the tunnel.<STRONG> The tunnel handles
+ traffic between the two protected subnets, not between the gateways</STRONG>
+ . Depending on the routing in place, a ping might</P>
+<UL>
+<LI>either succeed by finding an unencrypted route</LI>
+<LI>or fail by finding no route. Packets without an IPSEC eroute are
+ discarded.</LI>
+</UL>
+<P><STRONG>Neither event tells you anything about the tunnel</STRONG>.
+ You can explicitly create an eroute to force such packets through the
+ tunnel, or you can create additional tunnels as described in our<A HREF="#multitunnel">
+ configuration document</A>, but those may be unnecessary complications
+ in your situation.</P>
+<P>The trick is to explicitly test between<STRONG> both gateways'
+ private-side IP addresses</STRONG>. Since the private-side interfaces
+ are on the protected subnets, the resulting packets do go via the
+ tunnel. Use either ping -I or traceroute -i, both of which allow you to
+ specify a source interface. (Note: unsupported on older Linuxes). The
+ same principles apply for a road warrior (or other) case where only one
+ end of your tunnel is a subnet.</P>
+<H3><A NAME="ifconfig1"></A>5.3 ifconfig reports for KLIPS debugging</H3>
+<P>When diagnosing problems using ifconfig statistics, you may wonder
+ what type of activity increments a particular counter for an ipsecN
+ device. Here's an index, posted by KLIPS developer Richard Guy Briggs:</P>
+<PRE>Here is a catalogue of the types of errors that can occur for which
+statistics are kept when transmitting and receiving packets via klips.
+I notice that they are not necessarily logged in the right counter.
+. . .
+
+Sources of ifconfig statistics for ipsec devices
+
+rx-errors:
+- packet handed to ipsec_rcv that is not an ipsec packet.
+- ipsec packet with payload length not modulo 4.
+- ipsec packet with bad authenticator length.
+- incoming packet with no SA.
+- replayed packet.
+- incoming authentication failed.
+- got esp packet with length not modulo 8.
+
+tx_dropped:
+- cannot process ip_options.
+- packet ttl expired.
+- packet with no eroute.
+- eroute with no SA.
+- cannot allocate sk_buff.
+- cannot allocate kernel memory.
+- sk_buff internal error.
+
+
+The standard counters are:
+
+struct enet_statistics
+{
+        int        rx_packets;                /* total packets received */
+        int        tx_packets;                /* total packets transmitted */
+        int        rx_errors;                /* bad packets received */
+        int        tx_errors;                /* packet transmit problems */
+        int        rx_dropped;                /* no space in linux buffers */
+        int        tx_dropped;                /* no space available in linux */
+        int        multicast;                /* multicast packets received */
+        int        collisions;
+
+        /* detailed rx_errors: */
+        int        rx_length_errors;
+        int        rx_over_errors;                /* receiver ring buff overflow */
+        int        rx_crc_errors;                /* recved pkt with crc error */
+        int        rx_frame_errors;        /* recv'd frame alignment error */
+        int        rx_fifo_errors;                /* recv'r fifo overrun */
+        int        rx_missed_errors;        /* receiver missed packet */
+
+        /* detailed tx_errors */
+        int        tx_aborted_errors;
+        int        tx_carrier_errors;
+        int        tx_fifo_errors;
+        int        tx_heartbeat_errors;
+        int        tx_window_errors;
+};
+
+of which I think only the first 6 are useful.</PRE>
+<H3><A NAME="gdb"></A> 5.4 Using GDB on Pluto</H3>
+<P>You may need to use the GNU debugger, gdb(1), on Pluto. This should
+ be necessary only in unusual cases, for example if you encounter a
+ problem which the Pluto developer cannot readily reproduce or if you
+ are modifying Pluto.</P>
+<P>Here are the Pluto developer's suggestions for doing this:</P>
+<PRE>Can you get a core dump and use gdb to find out what Pluto was doing
+when it died?
+
+To get a core dump, you will have to set dumpdir to point to a
+suitable directory (see <A HREF="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</A>).
+
+To get gdb to tell you interesting stuff:
+        $ script
+        $ cd dump-directory-you-chose
+        $ gdb /usr/local/lib/ipsec/pluto core
+        (gdb) where
+        (gdb) quit
+        $ exit
+
+The resulting output will have been captured by the script command in
+a file called &quot;typescript&quot;.  Send it to the list.
+
+Do not delete the core file.  I may need to ask you to print out some
+more relevant stuff.</PRE>
+<P> Note that the<VAR> dumpdir</VAR> parameter takes effect only when
+ the IPsec subsystem is restarted -- reboot or ipsec setup restart.</P>
+<P>
+<BR>
+<BR></P>
+<HR>
+<H1><A name="compat">Linux FreeS/WAN Compatibility Guide</A></H1>
+<P>Much of this document is quoted directly from the Linux FreeS/WAN<A href="mail.html">
+ mailing list</A>. Thanks very much to the community of testers,
+ patchers and commenters there, especially the ones quoted below but
+ also various contributors we haven't quoted.</P>
+<H2><A name="spec">Implemented parts of the IPsec Specification</A></H2>
+<P>In general, do not expect Linux FreeS/WAN to do everything yet. This
+ is a work-in-progress and some parts of the IPsec specification are not
+ yet implemented.</P>
+<H3><A name="in">In Linux FreeS/WAN</A></H3>
+<P>Things we do, as of version 1.96:</P>
+<UL>
+<LI>key management methods
+<DL>
+<DT>manually keyed</DT>
+<DD>using keys stored in /etc/ipsec.conf</DD>
+<DT>automatically keyed</DT>
+<DD>Automatically negotiating session keys as required. All connections
+ are automatically re-keyed periodically. The<A href="#Pluto"> Pluto</A>
+ daemon implements this using the<A href="#IKE"> IKE</A> protocol.</DD>
+</DL>
+</LI>
+<LI>Methods of authenticating gateways for IKE
+<DL>
+<DT>shared secrets</DT>
+<DD>stored in<A href="manpage.d/ipsec.secrets.5.html"> ipsec.secrets(5)</A>
+</DD>
+<DT><A href="#RSA">RSA</A> signatures</DT>
+<DD>For details, see<A href="manpage.d/ipsec_pluto.8.html"> pluto(8)</A>
+.</DD>
+<DT>looking up RSA authentication keys from<A href="#DNS"> DNS</A>.</DT>
+<DD>Note that this technique cannot be fully secure until<A href="#SDNS">
+ secure DNS</A> is widely deployed.</DD>
+</DL>
+</LI>
+<LI>groups for<A href="#DH"> Diffie-Hellman</A> key negotiation
+<DL>
+<DT>group 2, modp 1024-bit</DT>
+<DT>group 5, modp 1536-bit</DT>
+<DD>We implement these two groups.
+<P>In negotiating a keying connection (ISAKMP SA, Phase 1) we propose
+ both groups when we are the initiator, and accept either when a peer
+ proposes them. Once the keying connection is made, we propose only the
+ alternative agreed there for data connections (IPsec SA's, Phase 2)
+ negotiated over that keying connection.</P>
+</DD>
+</DL>
+</LI>
+<LI>encryption transforms
+<DL>
+<DT><A href="#DES">DES</A></DT>
+<DD>DES is in the source code since it is needed to implement 3DES, but
+ single DES is not made available to users because<A href="#desnotsecure">
+ DES is insecure</A>.</DD>
+<DT><A href="#3DES">Triple DES</A></DT>
+<DD>implemented, and used as the default encryption in Linux FreeS/WAN.</DD>
+</DL>
+</LI>
+<LI>authentication transforms
+<DL>
+<DT><A href="#HMAC">HMAC</A> using<A href="#MD5"> MD5</A></DT>
+<DD>implemented, may be used in IKE or by by AH or ESP transforms.</DD>
+<DT><A href="#HMAC">HMAC</A> using<A href="#SHA"> SHA</A></DT>
+<DD>implemented, may be used in IKE or by AH or ESP transforms.</DD>
+</DL>
+<P>In negotiations, we propose both of these and accept either.</P>
+</LI>
+<LI>compression transforms
+<DL>
+<DT>IPComp</DT>
+<DD>IPComp as described in RFC 2393 was added for FreeS/WAN 1.6. Note
+ that Pluto becomes confused if you ask it to do IPComp when the kernel
+ cannot.</DD>
+</DL>
+</LI>
+</UL>
+<P>All combinations of implemented transforms are supported. Note that
+ some form of packet-level<STRONG> authentication is required whenever
+ encryption is used</STRONG>. Without it, the encryption will not be
+ secure.</P>
+<H3><A name="dropped">Deliberately omitted</A></H3>
+ We do not implement everything in the RFCs because some of those things
+ are insecure. See our discussions of avoiding<A href="#weak"> bogus
+ security</A>.
+<P>Things we deliberately omit which are required in the RFCs are:</P>
+<UL>
+<LI>null encryption (to use ESP as an authentication-only service)</LI>
+<LI>single DES</LI>
+<LI>DH group 1, a 768-bit modp group</LI>
+</UL>
+<P>Since these are the only encryption algorithms and DH group the RFCs
+ require, it is possible in theory to have a standards-conforming
+ implementation which will not interpoperate with FreeS/WAN. Such an
+ implementation would be inherently insecure, so we do not consider this
+ a problem.</P>
+<P>Anyway, most implementations sensibly include more secure options as
+ well, so dropping null encryption, single DES and Group 1 does not
+ greatly hinder interoperation in practice.</P>
+<P>We also do not implement some optional features allowed by the RFCs:</P>
+<UL>
+<LI>aggressive mode for negotiation of the keying channel or ISAKMP SA.
+ This mode is a little faster than main mode, but exposes more
+ information to an eavesdropper.</LI>
+</UL>
+<P>In theory, this should cause no interoperation problems since all
+ implementations are required to support the more secure main mode,
+ whether or not they also allow aggressive mode.</P>
+<P>In practice, it does sometimes produce problems with implementations
+ such as Windows 2000 where aggressive mode is the default. Typically,
+ these are easily solved with a configuration change that overrides that
+ default.</P>
+<H3><A name="not">Not (yet) in Linux FreeS/WAN</A></H3>
+<P>Things we don't yet do, as of version 1.96:</P>
+<UL>
+<LI>key management methods
+<UL>
+<LI>authenticate key negotiations via local<A href="#PKI"> PKI</A>
+ server, but see links to user<A href="#patch"> patches</A></LI>
+<LI>authenticate key negotiations via<A href="#SDNS"> secure DNS</A></LI>
+<LI>unauthenticated key management, using<A href="#DH"> Diffie-Hellman</A>
+ key agreement protocol without authentication. Arguably, this would be
+ worth doing since it is secure against all passive attacks. On the
+ other hand, it is vulnerable to an active<A href="#middle">
+ man-in-the-middle attack</A>.</LI>
+</UL>
+</LI>
+<LI>encryption transforms
+<P>Currently<A href="#3DES"> Triple DES</A> is the only encryption
+ method Pluto will negotiate.</P>
+<P>No additional encryption transforms are implemented, though the RFCs
+ allow them and some other IPsec implementations support various of
+ them. We are not eager to add more. See this<A href="#other.cipher">
+ FAQ question</A>.</P>
+<P><A href="#AES">AES</A>, the successor to the DES standard, is an
+ excellent candidate for inclusion in FreeS/WAN, see links to user<A href="#patch">
+ patches</A>.</P>
+</LI>
+<LI>authentication transforms
+<P>No optional additional authentication transforms are currently
+ implemented. Likely<A href="#SHA-256"> SHA-256, SHA-384 and SHA-512</A>
+ will be added when AES is.</P>
+</LI>
+<LI>Policy checking on decrypted packets
+<P>To fully comply with the RFCs, it is not enough just to accept only
+ packets which survive any firewall rules in place to limit what IPsec
+ packets get in, and then pass KLIPS authentication. That is what
+ FreeS/WAN currently does.</P>
+<P>We should also apply additional tests, for example ensuring that all
+ packets emerging from a particular tunnel have source and destination
+ addresses that fall within the subnets defined for that tunnel, and
+ that packets with those addresses that did not emerge from the
+ appropriate tunnel are disallowed.</P>
+<P>This will be done as part of a KLIPS rewrite. See these<A href="#applied">
+ links</A> and the<A href="mail.html"> design mailing list</A> for
+ discussion.</P>
+</LI>
+</UL>
+<H2><A name="pfkey">Our PF-Key implementation</A></H2>
+<P>We use PF-key Version Two for communication between the KLIPS kernel
+ code and the Pluto Daemon. PF-Key v2 is defined by<A href="http://www.normos.org/ietf/rfc/rfc2367.txt">
+ RFC 2367</A>.</P>
+<P>The &quot;PF&quot; stands for Protocol Family. PF-Inet defines a
+ kernel/userspace interface for the TCP/IP Internet protocols (TCP/IP),
+ and other members of the PF series handle Netware, Appletalk, etc.
+ PF-Key is just a PF for key-related matters.</P>
+<H3><A name="pfk.port">PF-Key portability</A></H3>
+<P>PF-Key came out of Berkeley Unix work and is used in the various BSD
+ IPsec implementations, and in Solaris. This means there is some hope of
+ porting our Pluto(8) to one of the BSD distributions, or of running
+ their photurisd(8) on Linux if you prefer<A href="#photuris"> Photuris</A>
+ key management over IKE.</P>
+<P>It is, however, more complex than that. The PK-Key RFC deliberately
+ deals only with keying, not policy management. The three PF-Key
+ implementations we have looked at -- ours, OpenBSD and KAME -- all have
+ extensions to deal with security policy, and the extensions are
+ different. There have been discussions aimed at sorting out the
+ differences, perhaps for a version three PF-Key spec. All players are
+ in favour of this, but everyone involved is busy and it is not clear
+ whether or when these discussions might bear fruit.</P>
+<H2><A name="otherk">Kernels other than the latest 2.2.x and 2.4.y</A></H2>
+<P>We develop and test on Redhat Linux using the most recent kernel in
+ the 2.2 and 2.4 series. In general, we recommend you use the latest
+ kernel in one of those series. Complications and caveats are discussed
+ below.</P>
+<H3><A name="kernel.2.0">2.0.x kernels</A></H3>
+<P>Consider upgrading to the 2.2 kernel series. If you want to stay with
+ the 2.0 series, then we strongly recommend 2.0.39. Some useful security
+ patches were added in 2.0.38.</P>
+<P>Various versions of the code have run at various times on most 2.0.xx
+ kernels, but the current version is only lightly tested on 2.0.39, and
+ not at all on older kernels.</P>
+<P>Some of our patches for older kernels are shipped in 2.0.37 and
+ later, so they are no longer provided in FreeS/WAN. This means recent
+ versions of FreeS/WAN will probably not compile on anything earlier
+ than 2.0.37.</P>
+<H3><A name="kernel.production">2.2 and 2.4 kernels</A></H3>
+<DL>
+<DT>FreeS/WAN 1.0</DT>
+<DD>ran only on 2.0 kernels</DD>
+<DT>FreeS/WAN 1.1 to 1.8</DT>
+<DD>ran on 2.0 or 2.2 kernels
+<BR> ran on some development kernels, 2.3 or 2.4-test</DD>
+<DT>FreeS/WAN 1.9 to 1.96</DT>
+<DD>runs on 2.0, 2.2 or 2.4 kernels</DD>
+</DL>
+<P>In general,<STRONG> we suggest the latest 2.2 kernel or 2.4 for
+ production use</STRONG>.</P>
+<P>Of course no release can be guaranteed to run on kernels more recent
+ than it is, so quite often there will be no stable FreeS/WAN for the
+ absolute latest kernel. See the<A href="#k.versions"> FAQ</A> for
+ discussion.</P>
+<H2><A name="otherdist">Intel Linux distributions other than Redhat</A></H2>
+<P>We develop and test on Redhat 6.1 for 2.2 kernels, and on Redhat 7.1
+ or 7.2 for 2.4, so minor changes may be required for other
+ distributions.</P>
+<H3><A name="rh7">Redhat 7.0</A></H3>
+<P>There are some problems with FreeS/WAN on Redhat 7.0. They are
+ soluble, but we recommend you upgrade to a later Redhat instead..</P>
+<P>Redhat 7 ships with two compilers.</P>
+<UL>
+<LI>Their<VAR> gcc</VAR> is version 2.96. Various people, including the
+ GNU compiler developers and Linus, have said fairly emphatically that
+ using this was a mistake. 2.96 is a development version, not intended
+ for production use. In particular, it will not compile a Linux kernel.</LI>
+<LI>Redhat therefore also ship a separate compiler, which they call<VAR>
+ kgcc</VAR>, for compiling kernels.</LI>
+</UL>
+<P>Kernel Makefiles have<VAR> gcc</VAR> as a default, and must be
+ adjusted to use<VAR> kgcc</VAR> before a kernel will compile on 7.0.
+ This mailing list message gives details:</P>
+<PRE>Subject: Re: AW: Installing IPsec on Redhat 7.0
+   Date: Thu, 1 Feb 2001 14:32:52 -0200 (BRST)
+  From: Mads Rasmussen &lt;mads@cit.com.br&gt;
+ 
+&gt; From www.redhat.com/support/docs/gotchas/7.0/gotchas-7-6.html#ss6.1
+
+cd to /usr/src/linux and open the Makefile in your favorite editor. You
+will need to look for a line similar to this:
+
+CC = $(CROSS_COMPILE)gcc -D__KERNEL__ -I$(HPATH)
+
+This line specifies which C compiler to use to build the kernel. It should
+be changed to:
+
+CC = $(CROSS_COMPILE)kgcc -D__KERNEL__ -I$(HPATH)
+
+for Red Hat Linux 7. The kgcc compiler is egcs 2.91.66. From here you can
+proceed with the typical compiling steps.</PRE>
+<P>Check the<A href="mail.html"> mailing list</A> archive for more
+ recent news.</P>
+<H3><A name="suse">SuSE Linux</A></H3>
+<P>SuSE 6.3 and later versions, at least in Europe, ship with FreeS/WAN
+ included.</P>
+<P>FreeS/WAN packages distributed for SuSE 7.0-7.2 were somehow
+ miscompiled. You can find fixed packages on<A HREF="http://www.suse.de/~garloff/linux/FreeSWAN">
+ Kurt Garloff's page</A>.</P>
+<P>Here are some notes for an earlier SuSE version.</P>
+<H4><A NAME="9_4_2_1">SuSE Linux 5.3</A></H4>
+<PRE>Date: Mon, 30 Nov 1998
+From: Peter Onion &lt;ponion@srd.bt.co.uk&gt;
+
+... I got Saturdays snapshot working between my two SUSE5.3 machines at home.
+
+The mods to the install process are quite simple.  From memory and looking at
+the files on the SUSE53 machine here at work....
+
+And extra link in each of the /etc/init.d/rc?.d directories called K35ipsec
+which SUSE use to shut a service down.
+
+A few mods in /etc/init.d/ipsec  to cope with the different places that SUSE
+put config info, and remove the inculsion of /etc/rc.d/init.d/functions and .
+/etc/sysconfig/network as they don't exists and 1st one isn't needed anyway.
+
+insert &quot;. /etc/rc.config&quot; to pick up the SUSE config info and use 
+
+  if test -n &quot;$NETCONFIG&quot; -a &quot;$NETCONFIG&quot; != &quot;YAST_ASK&quot; ; then
+
+to replace 
+
+  [ ${NETWORKING} = &quot;no&quot; ] &amp;&amp; exit 0
+
+Create /etc/sysconfig  as SUSE doesn't have one.
+
+I think that was all (but I prob forgot something)....</PRE>
+<P>You may also need to fiddle initialisation scripts to ensure that<VAR>
+ /var/run/pluto.pid</VAR> is removed when rebooting. If this file is
+ present, Pluto does not come up correctly.</P>
+<H3><A name="slack">Slackware</A></H3>
+<PRE>Subject: Re: linux-IPsec: Slackware distribution
+  Date:  Thu, 15 Apr 1999 12:07:01 -0700
+  From:  Evan Brewer &lt;dmessiah@silcon.com&gt;
+
+&gt; Very shortly, I will be needing to install IPsec on at least gateways that
+&gt; are running Slackware. . . .
+
+The only trick to getting it up is that on the slackware dist there is no
+init.d directory in /etc/rc.d .. so create one.  Then, what I do is take the
+IPsec startup script which normally gets put into the init.d directory, and
+put it in /etc/rc.d and name ir rc.ipsec .. then I symlink it to the file
+in init.d.  The only file in the dist you need to really edit is the
+utils/Makefile, setup4:
+
+Everything else should be just fine.</PRE>
+<P>A year or so later:</P>
+<PRE>Subject: Re: HTML Docs- Need some cleanup?
+   Date: Mon, 8 Jan 2001
+   From: Jody McIntyre &lt;jodym@oeone.com&gt;
+
+I have successfully installed FreeS/WAN on several Slackware 7.1 machines.
+FreeS/WAN installed its rc.ipsec file in /etc/rc.d.  I had to manually call
+this script from rc.inet2.  This seems to be an easier method than Evan
+Brewer's.</PRE>
+<H3><A name="deb">Debian</A></H3>
+<P>A recent (Nov 2001) mailing list points to a<A href="http://www.thing.dyndns.org/debian/vpn.htm">
+ web page</A> on setting up several types of tunnel, including IPsec, on
+ Debian.</P>
+<P>Some older information:</P>
+<PRE>Subject: FreeS/WAN 1.0 on Debian 2.1
+   Date: Tue, 20 Apr 1999
+  From:  Tim Miller &lt;cerebus+counterpane@haybaler.sackheads.org&gt;
+
+        Compiled and installed without error on a Debian 2.1 system
+with kernel-source-2.0.36 after pointing RCDIR in utils/Makefile to
+/etc/init.d.
+
+        /var/lock/subsys/ doesn't exist on Debian boxen, needs to be
+created; not a fatal error.
+
+        Finally, IPsec scripts appear to be dependant on GNU awk
+(gawk); the default Debian awk (mawk-1.3.3-2) had fatal difficulties.
+With gawk installed and /etc/alternatives/awk linked to /usr/bin/gawk
+operation appears flawless.</PRE>
+<P>The scripts in question have been modified since this was posted. Awk
+ versions should no longer be a problem.</P>
+<H3><A name="caldera">Caldera</A></H3>
+<PRE>Subject: Re: HTML Docs- Need some cleanup?
+   Date: Mon, 08 Jan 2001
+   From: Andy Bradford &lt;andyb@calderasystems.com&gt;
+
+On Sun, 07 Jan 2001 22:59:05 EST, Sandy Harris wrote:
+
+&gt;     Intel Linux distributions other than Redhat 5.x and 6.x 
+&gt;         Redhat 7.0 
+&gt;         SuSE Linux 
+&gt;             SuSE Linux 5.3 
+&gt;         Slackware 
+&gt;         Debian 
+
+Can you please include Caldera in this list?  I have tested it since 
+FreeS/Wan 1.1 and it works great with our systems---provided one 
+follows the FreeS/Wan documentation. :-)
+
+Thank you,
+Andy</PRE>
+<H2><A name="CPUs">CPUs other than Intel</A></H2>
+<P>FreeS/WAN has been run sucessfully on a number of different CPU
+ architectures. If you have tried it on one not listed here, please post
+ to the<A href="mail.html"> mailing list</A>.</P>
+<H3><A name=" strongarm">Corel Netwinder (StrongARM CPU)</A></H3>
+<PRE>Subject: linux-ipsec: Netwinder diffs
+Date: Wed, 06 Jan 1999
+From: rhatfield@plaintree.com
+
+I had a mistake in my IPsec-auto, so I got things working this morning.
+
+Following are the diffs for my changes.  Probably not the best and cleanest way 
+of doing it, but it works. . . . </PRE>
+<P>These diffs are in the 0.92 and later distributions, so these should
+ work out-of-the-box on Netwinder.</P>
+<H3><A name="yellowdog">Yellow Dog Linux on Power PC</A></H3>
+<PRE>Subject:  Compiling FreeS/WAN 1.1 on YellowDog Linux (PPC)
+   Date:  11 Dec 1999
+   From:  Darron Froese &lt;darron@fudgehead.com&gt;
+
+I'm summarizing here for the record - because it's taken me many hours to do
+this (multiple times) and because I want to see IPsec on more linuxes than
+just x86.
+
+Also, I can't remember if I actually did summarize it before... ;-) I'm
+working too many late hours.
+
+That said - here goes.
+
+1. Get your linux kernel and unpack into /usr/src/linux/ - I used 2.2.13.
+&lt;http://www.kernel.org/pub/linux/kernel/v2.2/linux-2.2.13.tar.bz2&gt;
+
+2. Get FreeS/WAN and unpack into /usr/src/freeswan-1.1
+&lt;ftp://ftp.xs4all.nl/pub/crypto/freeswan/freeswan-1.1.tar.gz&gt;
+
+3. Get the gmp src rpm from here:
+&lt;ftp://ftp.yellowdoglinux.com//pub/yellowdog/champion-1.1/SRPMS/SRPMS/gmp-2.0.2-9a.src.rpm&gt;
+
+4. Su to root and do this: rpm --rebuild gmp-2.0.2-9a.src.rpm
+
+You will see a lot of text fly by and when you start to see the rpm
+recompiling like this:
+
+Executing: %build
++ umask 022
++ cd /usr/src/redhat/BUILD
++ cd gmp-2.0.2
++ libtoolize --copy --force
+Remember to add `AM_PROG_LIBTOOL' to `configure.in'.
+You should add the contents of `/usr/share/aclocal/libtool.m4' to
+`aclocal.m4'.
++ CFLAGS=-O2 -fsigned-char
++ ./configure --prefix=/usr
+
+Hit Control-C to stop the rebuild. NOTE: We're doing this because for some
+reason the gmp source provided with FreeS/WAN 1.1 won't build properly on
+ydl.
+
+cd /usr/src/redhat/BUILD/
+cp -ar gmp-2.0.2 /usr/src/freeswan-1.1/
+cd /usr/src/freeswan-1.1/
+rm -rf gmp
+mv gmp-2.0.2 gmp
+
+5. Open the freeswan Makefile and change the line that says:
+KERNEL=$(b)zimage (or something like that) to
+KERNEL=vmlinux
+
+6. cd ../linux/
+
+7. make menuconfig
+Select an option or two and then exit - saving your changes.
+
+8. cd ../freeswan-1.1/ ; make menugo
+
+That will start the whole process going - once that's finished compiling,
+you have to install your new kernel and reboot.
+
+That should build FreeS/WAN on ydl (I tried it on 1.1).</PRE>
+ And a later message on the same topic:
+<PRE>Subject: Re: FreeS/WAN, PGPnet and E-mail
+   Date: Sat, 22 Jan 2000
+   From: Darron Froese &lt;darron@fudgehead.com&gt;
+
+on 1/22/00 6:47 PM, Philip Trauring at philip@trauring.com wrote:
+
+&gt; I have a PowerMac G3 ...
+
+The PowerMac G3 can run YDL 1.1 just fine. It should also be able to run
+FreeS/WAN 1.2patch1 with a couple minor modifications:
+
+1. In the Makefile it specifies a bzimage for the kernel compile - you have
+to change that to vmlinux for the PPC.
+
+2. The gmp source that comes with FreeS/WAN (for whatever reason) fails to
+compile. I have gotten around this by getting the gmp src rpm from here:
+
+ftp://ftp.yellowdoglinux.com//pub/yellowdog/champion-1.1/SRPMS/SRPMS/gmp-2.0.2-9a.src.rpm
+
+If you rip the source out of there - and place it where the gmp source
+resides it will compile just fine.</PRE>
+<P>FreeS/WAN no longer includes GMP source.</P>
+<H3><A name="mklinux">Mklinux</A></H3>
+<P>One user reports success on the Mach-based<STRONG> m</STRONG>icro<STRONG>
+k</STRONG>ernel Linux.</P>
+<PRE>Subject: Smiles on sparc and ppc
+   Date: Fri, 10 Mar 2000
+   From: Jake Hill &lt;jah@alien.bt.co.uk&gt;
+
+You may or may not be interested to know that I have successfully built
+FreeS/WAN on a number of non intel alpha architectures; namely on ppc
+and sparc and also on osfmach3/ppc (MkLinux). I can report that it just
+works, mostly, with few changes.</PRE>
+<H3><A name="alpha">Alpha 64-bit processors</A></H3>
+<PRE>Subject: IT WORKS (again) between intel &amp; alpha :-)))))
+   Date: Fri, 29 Jan 1999
+   From: Peter Onion &lt;ponion@srd.bt.co.uk&gt;
+
+Well I'm happy to report that I've got an IPsec connection between by intel &amp; alpha machines again :-))
+
+If you look back on this list to 7th of December I wrote...
+
+-On 07-Dec-98 Peter Onion wrote:
+-&gt; 
+-&gt; I've about had enuf of wandering around inside the kernel trying to find out
+-&gt; just what is corrupting outgoing packets...
+-
+-Its 7:30 in the evening .....
+-
+-I FIXED IT  :-))))))))))))))))))))))))))))))))
+-
+-It was my own fault :-((((((((((((((((((
+-
+-If you ask me very nicly I'll tell you where I was a little too over keen to
+-change unsigned long int __u32 :-)  OPSE ...
+-
+-So tomorrow it will full steam ahead to produce a set of diffs/patches against
+-0.91 
+-
+-Peter Onion.</PRE>
+<P>In general (there have been some glitches), FreeS/WAN has been
+ running on Alphas since then.</P>
+<H3><A name="SPARC">Sun SPARC processors</A></H3>
+<P>Several users have reported success with FreeS/WAN on SPARC Linux.
+ Here is one mailing list message:</P>
+<PRE>Subject: Smiles on sparc and ppc
+   Date: Fri, 10 Mar 2000
+   From: Jake Hill &lt;jah@alien.bt.co.uk&gt;
+
+You may or may not be interested to know that I have successfully built
+FreeS/WAN on a number of non intel alpha architectures; namely on ppc
+and sparc and also on osfmach3/ppc (MkLinux). I can report that it just
+works, mostly, with few changes.
+
+I have a question, before I make up some patches. I need to hack
+gmp/mpn/powerpc32/*.s to build them. Is this ok? The changes are
+trivial, but could I also use a different version of gmp? Is it vanilla
+here?
+
+I guess my only real headache is from ipchains, which appears to stop
+running when IPsec has been started for a while. This is with 2.2.14 on
+sparc.</PRE>
+<P>This message, from a different mailing list, may be relevant for
+ anyone working with FreeS/WAN on Suns:</P>
+<PRE>Subject: UltraSPARC DES assembler
+   Date: Thu, 13 Apr 2000
+   From: svolaf@inet.uni2.dk (Svend Olaf Mikkelsen)
+     To: coderpunks@toad.com
+
+An UltraSPARC assembler version of the LibDES/SSLeay/OpenSSL des_enc.c
+file is available at http://inet.uni2.dk/~svolaf/des.htm.
+
+This brings DES on UltraSPARC from slower than Pentium at the same
+clock speed to significantly faster.</PRE>
+<H3><A name="mips">MIPS processors</A></H3>
+<P>We know FreeS/WAN runs on at least some MIPS processors because<A href="http://www.lasat.com">
+ Lasat</A> manufacture an IPsec box based on an embedded MIPS running
+ Linux with FreeS/WAN. We have no details.</P>
+<H3><A name="crusoe">Transmeta Crusoe</A></H3>
+<P>The Merilus<A href="http://www.merilus.com/products/fc/index.shtml">
+ Firecard</A>, a Linux firewall on a PCI card, is based on a Crusoe
+ processor and supports FreeS/WAN.</P>
+<H3><A name="coldfire">Motorola Coldfire</A></H3>
+<PRE>Subject: Re: Crypto hardware support
+   Date: Mon, 03 Jul 2000
+   From: Dan DeVault &lt;devault@tampabay.rr.com&gt;
+
+.... I have been running
+uClinux with FreeS/WAN 1.4 on a system built by Moreton Bay  (
+http://www.moretonbay.com )  and it was using a Coldfire processor
+and was able to do the Triple DES encryption at just about
+1 mbit / sec rate.......  they put a Hi/Fn 7901 hardware encryption
+chip on their board and now their system does over 25 mbit of 3DES
+encryption........ pretty significant increase if you ask me.</PRE>
+<H2><A name="multiprocessor">Multiprocessor machines</A></H2>
+<P>FreeS/WAN is designed to work on SMP (symmetric multi-processing)
+ Linux machines and is regularly tested on dual processor x86 machines.</P>
+<P>We do not know of any testing on multi-processor machines with other
+ CPU architectures or with more than two CPUs. Anyone who does test
+ this, please report results to the<A href="mail.html"> mailing list</A>
+.</P>
+<P>The current design does not make particularly efficient use of
+ multiprocessor machines; some of the kernel work is single-threaded.</P>
+<H2><A name="hardware">Support for crypto hardware</A></H2>
+<P>Supporting hardware cryptography accelerators has not been a high
+ priority for the development team because it raises a number of fairly
+ complex issues:</P>
+<UL>
+<LI>Can you trust the hardware? If it is not Open Source, how do you
+ audit its security? Even if it is, how do you check that the design has
+ no concealed traps?</LI>
+<LI>If an interface is added for such hardware, can that interface be
+ subverted or misused?</LI>
+<LI>Is hardware acceleration actually a performance win? It clearly is
+ in many cases, but on a fast machine it might be better to use the CPU
+ for the encryption than to pay the overheads of moving data to and from
+ a crypto board.</LI>
+<LI>the current KLIPS code does not provide a clean interface for
+ hardware accelerators</LI>
+</UL>
+<P>That said, we have a<A href="#coldfire"> report</A> of FreeS/WAN
+ working with one crypto accelerator and some work is going on to modify
+ KLIPS to create a clean generic interface to such products. See this<A href="http://www.jukie.net/~bart/linux-ipsec/">
+ web page</A> for some of the design discussion.</P>
+<P>More recently, a patch to support some hardware accelerators has been
+ posted:</P>
+<PRE>Subject: [Design] [PATCH] H/W acceleration patch
+   Date: Tue, 18 Sep 2001
+   From: &quot;Martin Gadbois&quot; &lt;martin.gadbois@colubris.com&gt;
+ 
+Finally!!
+Here's a web site with H/W acceleration patch for FreeS/WAN 1.91, including
+S/W and Hifn 7901 crypto support.
+
+http://sources.colubris.com/
+
+Martin Gadbois</PRE>
+<P>Hardware accelerators could take performance well beyond what
+ FreeS/WAN can do in software (discussed<A href="performance.html"> here</A>
+). Here is some discussion off the IETF IPsec list, October 2001:</P>
+<PRE> ... Currently shipping chips deliver, 600 mbps throughput on a single
+ stream of 3DES IPsec traffic.  There are also chips that use multiple
+ cores to do 2.4 gbps.  We (Cavium) and others have announced even faster
+ chips. ... Mid 2002 versions will handle at line rate (OC48 and OC192)
+ IPsec and SSL/TLS traffic not only 3DES CBC but also AES and arc4.</PRE>
+<P>The patches to date support chips that have been in production for
+ some time, not the state-of-the-art latest-and-greatest devices
+ described in that post. However, they may still outperform software and
+ they almost certainly reduce CPU overhead.</P>
+<H2><A name="ipv6">IP version 6 (IPng)</A></H2>
+<P>The Internet currently runs on version four of the IP protocols. IPv4
+ is what is in the standard Linux IP stack, and what FreeS/WAN was built
+ for. In IPv4, IPsec is an optional feature.</P>
+<P>The next version of the IP protocol suite is version six, usually
+ abbreviated either as &quot;IPv6&quot; or as &quot;IPng&quot; for &quot;IP: the next
+ generation&quot;. For IPv6, IPsec is a required feature. Any machine doing
+ IPv6 is required to support IPsec, much as any machine doing (any
+ version of) IP is required to support ICMP.</P>
+<P>There is a Linux implementation of IPv6 in Linux kernels 2.2 and
+ above. For details, see the<A href="http://www.cs-ipv6.lancs.ac.uk/ipv6/systems/linux/faq/">
+ FAQ</A>. It does not yet support IPsec. The<A href="http://www.linux-ipv6.org/">
+ USAGI</A> project are also working on IPv6 for Linux.</P>
+<P>FreeS/WAN was originally built for the current standard, IPv4, but we
+ are interested in seeing it work with IPv6. Some progress has been
+ made, and a patched version with IPv6 support is<A href="http://www.ipv6.iabg.de/downloadframe/index.html">
+ available</A>. For more recent information, check the<A href="mail.html">
+ mailing list</A>.</P>
+<H3><A name="v6.back">IPv6 background</A></H3>
+<P>IPv6 has been specified by an IETF<A href="http://www.ietf.org/html.charters/ipngwg-charter.html">
+ working group</A>. The group's page lists over 30 RFCs to date, and
+ many Internet Drafts as well. The overview is<A href="http://www.ietf.org/rfc/rfc2460.txt">
+ RFC 2460</A>. Major features include:</P>
+<UL>
+<LI>expansion of the address space from 32 to 128 bits,</LI>
+<LI>changes to improve support for
+<UL>
+<LI>mobile IP</LI>
+<LI>automatic network configuration</LI>
+<LI>quality of service routing</LI>
+<LI>...</LI>
+</UL>
+</LI>
+<LI>improved security via IPsec</LI>
+</UL>
+<P>A number of projects are working on IPv6 implementation. A prominent
+ Open Source effort is<A href="http://www.kame.net/"> KAME</A>, a
+ collaboration among several large Japanese companies to implement IPv6
+ for Berkeley Unix. Other major players are also working on IPv6. For
+ example, see pages at:</P>
+<UL>
+<LI><A href="http://playground.sun.com/pub/ipng/html/ipng-main.html">Sun</A>
+</LI>
+<LI><A href="http://www.cisco.com/warp/public/732/ipv6/index.html">Cisco</A>
+</LI>
+<LI><A href="http://www.microsoft.com/windows2000/techinfo/howitworks/communications/networkbasics/IPv6.asp">
+Microsoft</A></LI>
+</UL>
+<P>The<A href="http://www.6bone.net/"> 6bone</A> (IPv6 backbone) testbed
+ network has been up for some time. There is an active<A href="http://www.ipv6.org/">
+ IPv6 user group</A>.</P>
+<P>One of the design goals for IPv6 was that it must be possible to
+ convert from v4 to v6 via a gradual transition process. Imagine the
+ mess if there were a &quot;flag day&quot; after which the entire Internet used
+ v6, and all software designed for v4 stopped working. Almost every
+ computer on the planet would need major software changes! There would
+ be huge costs to replace older equipment. Implementers would be worked
+ to death before &quot;the day&quot;, systems administrators and technical support
+ would be completely swamped after it. The bugs in every implementation
+ would all bite simultaneously. Large chunks of the net would almost
+ certainly be down for substantial time periods. ...</P>
+<P>Fortunately, the design avoids any &quot;flag day&quot;. It is therefore a
+ little tricky to tell how quickly IPv6 will take over. The transition
+ has certainly begun. For examples, see announcements from<A href="http://www.mailbase.ac.uk/lists/internet2/2000-03/0016.html">
+ NTT</A> and<A href="http://www.vnunet.com/News/1102383"> Nokia</A>.
+ However, it is not yet clear how quickly the process will gain
+ momentum, or when it will be completed. Likely large parts of the
+ Internet will remain with IPv4 for years to come.</P>
+<HR>
+<A NAME="interop"></A>
+<H1><A NAME="10">Interoperating with FreeS/WAN</A></H1>
+<P>The FreeS/WAN project needs you! We rely on the user community to
+ keep up to date. Mail users@lists.freeswan.org with your interop
+ success stories.</P>
+<P><STRONG>Please note</STRONG>: Most of our interop examples feature
+ Linux FreeS/WAN 1.x config files. You can convert them to 2.x files
+ fairly easily with the patch in our<A HREF="#ipsec.conf_v2"> Upgrading
+ Guide</A>.</P>
+<H2><A NAME="10_1">Interop at a Glance</A></H2>
+<TABLE BORDER="1">
+<TR><TD>&nbsp;</TD><TD colspan="5">FreeS/WAN VPN</TD><TD>Road Warrior</TD><TD>
+OE</TD></TR>
+<TR><TD>&nbsp;</TD><TD>PSK</TD><TD>RSA Secret</TD><TD>X.509
+<BR><SMALL><A HREF="#interoprules">(requires patch)</A></SMALL></TD><TD>
+NAT-Traversal
+<BR><SMALL><A HREF="#interoprules">(requires patch)</A></SMALL></TD><TD>
+Manual
+<BR>Keying</TD><TD>&nbsp;</TD><TD>&nbsp;</TD></TR>
+<TR><TD colspan="8">More Compatible</TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#freeswan">FreeS/WAN</A><A NAME="freeswan.top"> &nbsp;</A></TD><TD>
+<FONT color="#00cc00">Yes</FONT></TD><TD><FONT color="#00cc00">Yes</FONT>
+</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD><FONT color="#00cc00">Yes</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#isakmpd">isakmpd (OpenBSD)</A><A NAME="isakmpd.top"> &nbsp;</A>
+</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>
+<FONT color="#cc0000">No&nbsp;&nbsp;&nbsp;&nbsp;</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#kame">Kame (FreeBSD,
+<BR> NetBSD, MacOSX)
+<BR> <SMALL>aka racoon</SMALL></A><A NAME="kame.top"> &nbsp;</A></TD><TD><FONT
+color="#00cc00">Yes</FONT></TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>
+<FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#mcafee">McAfee VPN
+<BR><SMALL>was PGPNet</SMALL></A><A NAME="mcafee.top"> &nbsp;</A></TD><TD><FONT
+color="#00cc00">Yes</FONT></TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>
+<FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#microsoft">Microsoft
+<BR> Windows 2000/XP</A><A NAME="microsoft.top"> &nbsp;</A></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD><FONT color="#cc0000">
+No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#ssh">SSH Sentinel</A><A NAME="ssh.top"> &nbsp;</A></TD><TD><FONT
+color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT>
+</TD><TD><FONT color="#cccc00">Maybe</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#safenet">Safenet SoftPK
+<BR>/SoftRemote</A><A NAME="safenet.top"> &nbsp;</A></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD><FONT color="#cc0000">
+No</FONT></TD></TR>
+<TR><TD colspan="8">Other</TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#6wind">6Wind</A><A NAME="6wind.top"> &nbsp;</A></TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+<FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#alcatel">Alcatel Timestep</A><A NAME="alcatel.top"> &nbsp;</A>
+</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#apple">Apple Macintosh
+<BR>System 10+</A><A NAME="apple.top"> &nbsp;</A></TD><TD><FONT color="#cccc00">
+Maybe</FONT></TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD><FONT color="#cccc00">
+Maybe</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#cccc00">Maybe</FONT></TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#ashleylaurent">AshleyLaurent
+<BR> VPCom</A><A NAME="ashleylaurent.top"> &nbsp;</A></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT
+color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#borderware">Borderware</A><A NAME="borderware.top"> &nbsp;</A>
+</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD><TD><FONT color="#cc0000">
+No</FONT></TD></TR>
+
+<!--
+http://www.cequrux.com/vpn-guides.php3
+"coming soon" guide to connect with FreeS/WAN.
+-->
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#checkpoint">Check Point FW-1/VPN-1</A><A NAME="checkpoint.top">
+ &nbsp;</A></TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>
+<FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#cisco">Cisco with 3DES</A><A NAME="cisco.top"> &nbsp;</A></TD><TD>
+<FONT color="#00cc00">Yes</FONT></TD><TD><FONT color="#cccc00">Maybe</FONT>
+</TD><TD>&nbsp;</TD><TD><FONT color="#cccc00">Maybe</FONT></TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#equinux">Equinux VPN Tracker
+<BR> (for Mac OS X)</A><A NAME="equinux.top"> &nbsp;</A></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#cccc00">Maybe</FONT></TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#fsecure">F-Secure</A><A NAME="fsecure.top"> &nbsp;</A></TD><TD>
+<FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#cccc00">
+Maybe</FONT></TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#gauntlet">Gauntlet GVPN</A><A NAME="gauntlet.top"> &nbsp;</A>
+</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#cc0000">
+No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#aix">IBM AIX</A><A NAME="aix.top"> &nbsp;</A></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#cccc00">Maybe</FONT></TD><TD>
+&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#as400">IBM AS/400</A><A NAME="as400"> &nbsp;</A></TD><TD><FONT
+color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#intel">Intel Shiva
+<BR>LANRover/Net Structure</A><A NAME="intel.top"> &nbsp;</A></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT
+color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#lancom">LanCom (formerly ELSA)</A><A NAME="lancom.top">
+ &nbsp;</A></TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#linksys">Linksys</A><A NAME="linksys.top"> &nbsp;</A></TD><TD>
+<FONT color="#cccc00">Maybe</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#cc0000">
+No</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>
+<FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#lucent">Lucent</A><A NAME="lucent.top"> &nbsp;</A></TD><TD><FONT
+color="#cccc00">Partial</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#netasq">Netasq</A><A NAME="netasq.top"> &nbsp;</A></TD><TD>
+&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#netcelo">netcelo</A><A NAME="netcelo.top"> &nbsp;</A></TD><TD>
+&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#netgear">Netgear fvs318</A><A NAME="netgear.top"> &nbsp;</A>
+</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#netscreen">Netscreen 100
+<BR>or 5xp</A><A NAME="netscreen.top"> &nbsp;</A></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#cccc00">
+Maybe</FONT></TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#nortel">Nortel Contivity</A><A NAME="nortel.top"> &nbsp;</A>
+</TD><TD><FONT color="#cccc00">Partial</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD><FONT color="#cccc00">Maybe</FONT></TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#radguard">RadGuard</A><A NAME="radguard.top"> &nbsp;</A></TD><TD>
+<FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#raptor">Raptor</A><A NAME="raptor"> &nbsp;</A></TD><TD><FONT
+color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#redcreek">Redcreek Ravlin</A><A NAME="redcreek.top"> &nbsp;</A>
+</TD><TD><FONT color="#00cc00">Yes</FONT><FONT color="#cccc00">/Partial</FONT>
+</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#cc0000">
+No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#sonicwall">SonicWall</A><A NAME="sonicwall.top"> &nbsp;</A></TD><TD>
+<FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT
+color="#cccc00">Maybe</FONT></TD><TD><FONT color="#cc0000">No</FONT></TD><TD>
+<FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#sun">Sun Solaris</A><A NAME="sun.top"> &nbsp;</A></TD><TD><FONT
+color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT>
+</TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT
+color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#symantec">Symantec</A><A NAME="symantec.top"> &nbsp;</A></TD><TD>
+<FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#watchguard">Watchguard
+<BR> Firebox</A><A NAME="watchguard.top"> &nbsp;</A></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#xedia">Xedia Access Point
+<BR>/QVPN</A><A NAME="xedia.top"> &nbsp;</A></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT
+color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#zyxel">Zyxel Zywall
+<BR>/Prestige</A><A NAME="zyxel.top"> &nbsp;</A></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT
+color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE
+
+
+<TR>
+<TD><A HREF="#sample">sample</A></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+-->
+<TR><TD>&nbsp;</TD><TD>PSK</TD><TD>RSA Secret</TD><TD>X.509
+<BR><SMALL><A HREF="#interoprules">(requires patch)</A></SMALL></TD><TD>
+NAT-Traversal
+<BR><SMALL><A HREF="#interoprules">(requires patch)</A></SMALL></TD><TD>
+Manual
+<BR>Keying</TD><TD>&nbsp;</TD><TD>&nbsp;</TD></TR>
+<TR><TD>&nbsp;</TD><TD colspan="5">FreeS/WAN VPN</TD><TD>Road Warrior</TD><TD>
+OE</TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+</TABLE>
+<H3><A NAME="10_1_1">Key</A></H3>
+<TABLE BORDER="1">
+<TR><TD><FONT color="#00cc00">Yes</FONT></TD><TD>People report that this
+ works for them.</TD></TR>
+<TR><TD>[Blank]</TD><TD>We don't know.</TD></TR>
+<TR><TD><FONT color="#cc0000">No</FONT></TD><TD>We have reason to
+ believe it was, at some point, not possible to get this to work.</TD></TR>
+<TR><TD><FONT color="#cccc00">Partial</FONT></TD><TD>Partial success.
+ For example, a connection can be created from one end only.</TD></TR>
+<TR><TD><FONT color="#00cc00">Yes</FONT><FONT color="#cccc00">/Partial</FONT>
+</TD><TD>Mixed reports.</TD></TR>
+<TR><TD><FONT color="#cccc00">Maybe</FONT></TD><TD>We think the answer
+ is &quot;yes&quot;, but need confirmation.</TD></TR>
+</TABLE>
+<A NAME="interoprules"></A>
+<H2><A NAME="10_2">Basic Interop Rules</A></H2>
+<P>Vanilla FreeS/WAN implements<A HREF="#compat"> these parts</A> of the
+ IPSec specifications. You can add more with<A HREF="http://www.freeswan.ca">
+ Super FreeS/WAN</A>, but what we offer may be enough for many users.</P>
+<UL>
+<LI> To use X.509 certificates with FreeS/WAN, you will need the<A HREF="http://www.strongsec.org/freeswan">
+ X.509 patch</A> or<A HREF="http://www.freeswan.ca"> Super FreeS/WAN</A>
+, which includes that patch.</LI>
+<LI> To use<A HREF="#NAT.gloss"> Network Address Translation</A> (NAT)
+ traversal with FreeS/WAN, you will need Arkoon Network Security's<A HREF="http://open-source.arkoon.net">
+ NAT traversal patch</A> or<A HREF="http://www.freeswan.ca"> Super
+ FreeS/WAN</A>, which includes it.</LI>
+</UL>
+<P>We offer a set of proposals which is not user-adjustable, but covers
+ all combinations that we can offer. FreeS/WAN always proposes triple
+ DES encryption and Perfect Forward Secrecy (PFS). In addition, we
+ propose Diffie Hellman groups 5 and 2 (in that order), and MD5 and
+ SHA-1 hashes. We accept the same proposals, in the same order of
+ preference.</P>
+<P>Other interop notes:</P>
+<UL>
+<LI> A<A HREF="http://lists.freeswan.org/archives/users/2003-September/msg00462.html">
+ SHA-1 bug in FreeS/WAN 2.00, 2.01 and 2.02</A> may affect some interop
+ scenarios. It does not affect 1.x versions, and is fixed in 2.03 and
+ later.</LI>
+<LI> Some other implementations will close a connection with FreeS/WAN
+ after some time. This may be a problem with rekey lifetimes. Please see<A
+HREF="http://lists.freeswan.org/archives/users/2003-October/msg00293.html">
+ this tip</A> and<A HREF="http://lists.freeswan.org/pipermail/users/2001-December/005758.html">
+ this workaround</A>.</LI>
+</UL>
+<H2><A NAME="10_3">Longer Stories</A></H2>
+<H3><A NAME="10_3_1">For<EM> More Compatible</EM> Implementations</A></H3>
+<H4><A NAME="freeswan">FreeS/WAN</A></H4>
+<P> See our documentation at<A HREF="http://www.freeswan.org">
+ freeswan.org</A> and the Super FreeS/WAN docs at<A HREF="http://www.freeswan.ca">
+ freeswan.ca</A>. Some user-written HOWTOs for FreeS/WAN-FreeS/WAN
+ connections are listed in<A HREF="#howto"> our Introduction</A>.</P>
+<P>See also:</P>
+<UL>
+<LI><A HREF="http://lugbe.ch/action/reports/ipsec_htbe.phtml"> A German
+ FreeS/WAN-FreeS/WAN page by Markus Wernig (X.509)</A></LI>
+</UL>
+<P><A HREF="#freeswan.top">Back to chart</A></P>
+<H4><A NAME="isakmpd">isakmpd (OpenBSD)</A></H4>
+<P><A HREF="http://www.openbsd.org/faq/faq13.html">OpenBSD FAQ: Using
+ IPsec</A>
+<BR><A HREF="http://www.rommel.stw.uni-erlangen.de/~hshoexer/ipsec-howto/HOWTO.html">
+ Hans-Joerg Hoexer's interop Linux-OpenBSD (PSK)</A>
+<BR><A HREF="http://www.segfault.net/ipsec/"> Skyper's configuration
+ (PSK)</A>
+<BR><A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+ French page with configs (X.509)</A></P>
+<P><A HREF="#isakmpd.top">Back to chart</A></P>
+<H4><A NAME="kame">Kame</A></H4>
+<UL>
+<LI>For FreeBSD and NetBSD. Ships with Mac OS X; see also our<A HREF="#apple">
+ Mac</A> section.</LI>
+<LI>Also known as<EM> racoon</EM>, its keying daemon.</LI>
+</UL>
+<P><A HREF="http://www.kame.net">Kame homepage, with FAQ</A>
+<BR><A HREF="http://www.netbsd.org/Documentation/network/ipsec">
+ NetBSD's IPSec FAQ</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/12/msg00560.html">
+ Ghislaine's post explaining some interop peculiarities</A></P>
+<P><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/09/msg00511.html">
+ Itojun's Kame-FreeS/WAN interop tips (PSK)</A>
+<BR><A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2000"> Ghislaine
+ Labouret's French page with links to matching FreeS/WAN and Kame
+ configs (RSA)</A>
+<BR><A HREF="http://lugbe.ch/lostfound/contrib/freebsd_router/"> Markus
+ Wernig's HOWTO (X.509, BSD gateway)</A>
+<BR><A HREF="http://web.morgul.net/~frodo/docs/kame+freeswan_interop.html">
+ Frodo's Kame-FreeS/WAN interop (X.509)</A>
+<BR><A HREF="http://www.wavesec.org/kame.phtml"> Kame as a WAVEsec
+ client.</A></P>
+<P><A HREF="#kame.top">Back to chart</A></P>
+<H4><A NAME="mcafee">PGPNet/McAfee</A></H4>
+<P></P>
+<UL>
+<LI>Now called McAfee VPN Client.</LI>
+<LI>PGPNet also came in a freeware version which did not support subnets</LI>
+<LI>To support dhcp-over-ipsec, you need the X.509 patch, which is
+ included in<A HREF="http://www.freeswan.ca"> Super FreeS/WAN</A>.</LI>
+</UL>
+<P><A HREF="http://www.freeswan.ca/docs/WindowsInterop"> Tim Carr's
+ Windows Interop Guide (X.509)</A>
+<BR><A HREF="http://www.rommel.stw.uni-erlangen.de/~hshoexer/ipsec-howto/HOWTO.html#Interop2">
+ Hans-Joerg Hoexer's Guide for Linux-PGPNet (PSK)</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/04/msg00339.html">
+ Kai Martius' instructions using RSA Key-Extractor Tool (RSA)</A>
+<BR> &nbsp;&nbsp;&nbsp;&nbsp;<A HREF="http://www.zengl.net/freeswan/english.html">Christian
+ Zeng's page (RSA)</A> based on Kai's work. English or German.
+<BR><A HREF="http://tirnanog.ls.fi.upm.es/CriptoLab/Biblioteca/InfTech/InfTech_CriptoLab.htm">
+ Oscar Delgado's PDF (X.509, no configs)</A>
+<BR><A HREF="http://www-ec.njit.edu/~rxt1077/Howto.txt"> Ryan's HOWTO
+ for FreeS/WAN-PGPNet (X.509)</A>. Through a Linksys Router with IPsec
+ Passthru enabled.
+<BR><A HREF="http://jixen.tripod.com/#RW-PGP-to-Fwan"> Jean-Francois
+ Nadeau's Practical Configuration (Road Warrior with PSK)</A>
+<BR><A HREF="http://www.evolvedatacom.nl/freeswan.html#toc"> Wouter
+ Prins' HOWTO (Road Warrior with X.509)</A>
+<BR></P>
+<P><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/01/msg00271.html">
+ Rekeying problem with FreeS/WAN and older PGPNets</A>
+<BR></P>
+<P><A HREF="http://www.strongsec.com/freeswan/dhcprelay/index.htm"> DHCP
+ over IPSEC HOWTO for FreeS/WAN (requires X.509 and dhcprelay patches)</A>
+</P>
+<P><A HREF="#mcafee.top">Back to chart</A></P>
+<H4><A NAME="microsoft">Microsoft Windows 2000/XP</A></H4>
+<UL>
+<LI>IPsec comes with Win2k, and with XP Support Tools. May require<A HREF="http://www.microsoft.com/windows2000/downloads/recommended/encryption/default.asp">
+ High Encryption Pack</A>. WinXP users have also reported better results
+ with Service Pack 1.</LI>
+<LI>The Road Warrior setup works either way round. Windows (XP or 2K)
+ IPsec can connect as a Road Warrior to FreeS/WAN. However, FreeS/WAN
+ can also successfully connect as a Road Warrior to Windows IPsec (see
+ Nate Carlson's configs below).</LI>
+<LI>FreeS/WAN version 1.92 or later is required to avoid an
+ interoperation problem with Windows native IPsec. Earlier FreeS/WAN
+ versions did not process the Commit Bit as Windows native IPsec
+ expected.</LI>
+</UL>
+<P><A HREF="http://www.freeswan.ca/docs/WindowsInterop"> Tim Carr's
+ Windows Interop Guide (X.509)</A>
+<BR><A HREF="http://ipsec.math.ucla.edu/services/ipsec.html"> James
+ Carter's instructions (X.509, NAT-T)</A>
+<BR><A HREF="http://jixen.tripod.com/#Win2000-Fwan"> Jean-Francois
+ Nadeau's Net-net Configuration (PSK)</A>
+<BR><A HREF="http://security.nta.no/freeswan-w2k.html"> Telenor's
+ Node-node Config (Transport-mode PSK)</A>
+<BR><A HREF="http://vpn.ebootis.de"> Marcus Mueller's HOWTO using his
+ VPN config tool (X.509).</A> Tool also works with PSK.
+<BR><A HREF="http://www.natecarlson.com/include/showpage.php?cat=linux&page=ipsec-x509">
+ Nate Carlson's HOWTO using same tool (Road Warrior with X.509)</A>.
+ Unusually, FreeS/WAN is the Road Warrior here.
+<BR><A HREF="http://tirnanog.ls.fi.upm.es/CriptoLab/Biblioteca/InfTech/InfTech_CriptoLab.htm">
+ Oscar Delgado's PDF (X.509, no configs)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2003-July/022425.html">
+ Tim Scannell's Windows XP Additional Checklist (X.509)</A>
+<BR></P>
+
+<!-- Note to self: Include L2TP references? -->
+<P><A HREF="http://www.microsoft.com/windows2000/en/server/help/default.asp?url=/windows2000/en/server/help/sag_TCPIP_ovr_secfeatures.htm">
+ Microsoft's page on Win2k TCP/IP security features</A>
+<BR><A HREF="http://support.microsoft.com/support/kb/articles/Q257/2/25.ASP">
+ Microsoft's Win2k IPsec debugging tips</A>
+<BR>
+<!-- Alt-URL http://support.microsoft.com/default.aspx?scid=kb;EN-US;q257225
+Perhaps newer? -->
+<A HREF="http://www.wired.com/news/technology/0,1282,36336,00.html">
+ MS VPN may fall back to 1DES</A></P>
+<P><A HREF="#microsoft.top">Back to chart</A></P>
+<H4><A NAME="ssh">SSH Sentinel</A></H4>
+<UL>
+<LI>Popular and well tested.</LI>
+<LI>Also rebranded in<A HREF="http://www.zyxel.com"> Zyxel Zywall</A>.
+ Our Zyxel interop notes are<A HREF="#zyxel"> here</A>.</LI>
+<LI> SSH supports IPsec-over-UDP NAT traversal.</LI>
+<LI>There is this<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/12/msg00370.html">
+ potential problem</A> if you're not using the Legacy Proposal option.</LI>
+</UL>
+<P><A HREF="http://www.ssh.com/support/sentinel/documents.cfm"> SSH's
+ Sentinel-FreeSWAN interop PDF (X.509)</A>
+<BR><A HREF="http://www.nadmm.com/show.php?story=articles/vpn.inc">
+ Nadeem Hassan's SUSE-to-Sentinel article (Road warrior with X.509)</A>
+<BR><A HREF="http://www.zerozone.it/documents/Linux/HowTo/VPN-IPsec-Freeswan-HOWTO.html">
+ O-Zone's Italian HOWTO (Road Warrior, X.509, DHCP)</A>
+<BR></P>
+<P><A HREF="#ssh.top">Back to chart</A></P>
+<H4><A NAME="safenet">Safenet SoftPK/SoftRemote</A></H4>
+<UL>
+<LI>People recommend SafeNet as a low cost Windows client.</LI>
+<LI>SoftRemote seems to be the newer name for SoftPK.</LI>
+</UL>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2001-November/005061.html">
+ Whit Blauvelt's SoftRemote tips</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-October/015591.html">
+ Tim Wilson's tips (X.509)</A><A HREF="http://lists.freeswan.org/archives/users/2003-October/msg00607.html">
+ Workaround for a &quot;gotcha&quot;</A></P>
+<P><A HREF="http://jixen.tripod.com/#Rw-IRE-to-Fwan"> Jean-Francois
+ Nadeau's Practical Configuration (Road Warrior with PSK)</A>
+<BR><A HREF="http://www.terradoncommunications.com/security/whitepapers/safe_net-to-free_swan.pdf">
+ Terradon Communications' PDF (Road Warrior with PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-October/?????.html">
+ Seaan.net's PDF (Road Warrior to Subnet, with PSK)</A>
+<BR><A HREF="http://www.redbaronconsulting.com/freeswan/fswansafenet.pdf">
+ Red Baron Consulting's PDF (Road Warrior with X.509)</A></P>
+<P><A HREF="#safenet.top">Back to chart</A></P>
+<H3><A NAME="10_3_2">For<EM> Other Implementations</EM></A></H3>
+<H4><A NAME="6wind">6Wind</A></H4>
+<P><A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+ French page with configs (X.509)</A></P>
+<P><A HREF="#6wind.top">Back to chart</A></P>
+<H4><A NAME="alcatel">Alcatel Timestep</A></H4>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2002-June/011878.html">
+ Alain Sabban's settings (PSK or PSK road warrior; through static NAT)</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/1999/06/msg00100.html">
+ Derick Cassidy's configs (PSK)</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/1999/08/msg00194.html">
+ David Kerry's Timestep settings (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-August/013711.html">
+ Kevin Gerbracht's ipsec.conf (X.509)</A></P>
+<P><A HREF="#alcatel.top">Back to chart</A></P>
+<H4><A NAME="apple">Apple Macintosh System 10+</A></H4>
+<UL>
+<LI>Since the system is based on FreeBSD, this should interoperate<A HREF="#kame">
+ just like FreeBSD</A>.</LI>
+<LI> To use Appletalk over IPsec tunnels,<A HREF="http://lists.freeswan.org/pipermail/users/2001-November/005116.html">
+ run it over TCP/IP</A>, or use Open Door Networks' Shareway IP tool,<A HREF="http://lists.freeswan.org/pipermail/users/2001-November/005426.html">
+ described here.</A></LI>
+<LI>See also the<A HREF="#equinux"> Equinux VPN Tracker</A> for Mac OS
+ X.</LI>
+</UL>
+<P><A HREF="http://ipsec.math.ucla.edu/services/ipsec.html"> James
+ Carter's instructions (X.509, NAT-T)</A></P>
+<P><A HREF="#apple.top">Back to chart</A></P>
+<H4><A NAME="ashleylaurent">AshleyLaurent VPCom</A></H4>
+<P><A HREF="http://www.ashleylaurent.com/newsletter/01-28-00.htm">
+ Successful interop report, no details</A></P>
+<P><A HREF="#ashleylaurent.top">Back to chart</A></P>
+<H4><A NAME="borderware">Borderware</A></H4>
+<UL>
+<LI>I suspect the Borderware client is a rebranded Safenet. If that's
+ true, our<A HREF="#safenet"> Safenet section</A> will help.</LI>
+</UL>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2002-March/008288.html">
+ Philip Reetz' configs (PSK)</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/09/msg00217.html">
+ Borderware server does not support FreeS/WAN road warriors</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-February/007733.html">
+ Older Borderware may not support Diffie Hellman groups 2, 5</A>
+<BR></P>
+<P><A HREF="#borderware.top">Back to chart</A></P>
+<H4><A NAME="checkpoint">Check Point VPN-1 or FW-1</A></H4>
+<UL>
+<LI><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/02/msg00099.html">
+ Caveat about IP-range inclusion on Check Point.</A></LI>
+<LI> Some versions of Check Point may require an aggressive mode patch
+ to interoperate with FreeS/WAN.
+<BR><A HREF="http://www.freeswan.ca/code/super-freeswan"> Super
+ FreeS/WAN</A> now features this patch.
+<!--
+<A HREF="http://www.freeswan.ca/patches/aggressivemode">Steve Harvey's 
+aggressive mode patch for FreeS/WAN 1.5</A>
+-->
+</LI>
+<LI></LI>
+<LI>A Linux FreeS/WAN-Checkpoint connection may close after some time.
+ Try<A HREF="http://lists.freeswan.org/archives/users/2003-October/msg00293.html">
+ this tip</A> toward a workaround.</LI>
+</UL>
+<P><A HREF="http://www.fw-1.de/aerasec/ng/vpn-freeswan/CPNG+Linux-FreeSWAN.html">
+ AERAsec's Firewall-1 NG site (PSK, X.509, Road Warrior with X.509,
+ other algorithms)</A>
+<BR> &nbsp;&nbsp;&nbsp;&nbsp;<A HREF="http://www.fw-1.de/aerasec/ng/vpn-freeswan/CPNG+Linux-FreeSWAN.html#support-matrix">
+ AERAsec's detailed Check Point-FreeS/WAN support matrix</A>
+<BR><A HREF="http://support.checkpoint.com/kb/docs/public/firewall1/4_1/pdf/fw-linuxvpn.pdf">
+ Checkpoint.com PDF: Linux as a VPN Client to FW-1 (PSK)</A>
+<BR><A HREF="http://www.phoneboy.com"> PhoneBoy's Check Point FAQ (on
+ Check Point only, not FreeS/WAN)</A>
+<BR></P>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2001-August/002351.html">
+ Chris Harwell's tips FreeS/WAN configs (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-April/009362.html">
+ Daniel Tombeil's configs (PSK)</A></P>
+<P><A HREF="#checkpoint.top">Back to chart</A></P>
+<H4><A NAME="cisco">Cisco</A></H4>
+<UL>
+<LI> Cisco supports IPsec-over-UDP NAT traversal.</LI>
+<LI>Cisco VPN Client appears to use nonstandard IPsec and does not work
+ with FreeS/WAN.<A HREF="https://mj2.freeswan.org/archives/2003-August/maillist.html">
+ This message</A> concerns Cisco VPN Client 4.01.
+<!-- fix link -->
+</LI>
+<LI>A Linux FreeS/WAN-Cisco connection may close after some time.<A HREF="http://lists.freeswan.org/pipermail/users/2001-December/005758.html">
+ Here</A> is a workaround, and<A HREF="http://lists.freeswan.org/archives/users/2003-October/msg00293.html">
+ here</A> is another comment on the same subject.</LI>
+<LI><A HREF="http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120t/120t2/3desips.htm">
+Older Ciscos</A> purchased outside the United States may not have 3DES,
+ which FreeS/WAN requires.</LI>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2001-June/000406.html">
+RSA keying may not be possible between Cisco and FreeS/WAN.</A></LI>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2001-October/004357.html">
+In ipsec.conf, VPN3000 DN (distinguished name) must be in binary (X.509
+ only)</A></LI>
+</UL>
+<P><A HREF="http://rr.sans.org/encryption/cisco_router.php"> SANS
+ Institute HOWTO (PSK).</A> Detailed, with extensive references.
+<BR><A HREF="http://www.worldbank.ro/IPSEC/cisco-linux.txt"> Short HOWTO
+ (PSK)</A>
+<BR><A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+ French page with configs for Cisco IOS, PIX and VPN 3000 (X.509)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2001-August/002966.html">
+ Dave McFerren's sample configs (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2001-September/003422.html">
+ Wolfgang Tremmel's sample configs (PSK road warrior)</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/11/msg00578.html">
+ Old doc from Pete Davis, with William Watson's updated Tips (PSK)</A>
+<BR></P>
+<P><STRONG>Some PIX specific information:</STRONG>
+<BR><A HREF="http://www.wlug.org.nz/FreeSwanToCiscoPix"> Waikato Linux
+ Users' Group HOWTO. Nice detail (PSK)</A>
+<BR><A HREF="http://www.johnleach.co.uk/documents/freeswan-pix/freeswan-pix.html">
+ John Leach's configs (PSK)</A>
+<BR><A HREF="http://www.diverdown.cc/vpn/freeswanpix.html"> Greg
+ Robinson's settings (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-February/007901.html">
+ Scott's ipsec.conf for PIX (PSK, FreeS/WAN side only)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2001-October/003949.html">
+ Rick Trimble's PIX and FreeS/WAN settings (PSK)</A>
+<BR></P>
+<P><A href="http://www.cisco.com/public/support/tac"> Cisco VPN support
+ page</A>
+<BR><A href="http://www.ieng.com/warp/public/707/index.shtml#ipsec">
+ Cisco IPsec information page</A></P>
+<P><A HREF="#cisco.top">Back to chart</A></P>
+<H4><A NAME="equinux">Equinux VPN tracker (for Mac OS X)</A></H4>
+<UL>
+<LI>Graphical configurator for Mac OS X IPsec. May be an interface to
+ the<A HREF="#apple"> native Mac OS X IPsec</A>, which is essentially<A HREF="#kame">
+ KAME</A>.</LI>
+<LI>To use Appletalk over IPsec tunnels,<A HREF="http://lists.freeswan.org/pipermail/users/2001-November/005116.html">
+ run it over TCP/IP</A>, or use Open Door Networks' Shareway IP tool,<A HREF="http://lists.freeswan.org/pipermail/users/2001-November/005426.html">
+ described here.</A></LI>
+</UL>
+<P> Equinux provides<A HREF="http://www.equinux.com/download/HowTo_FreeSWAN.pdf">
+ this excellent interop PDF</A> (PSK, RSA, X.509).</P>
+<P><A HREF="#equinux.top">Back to chart</A></P>
+<H4><A NAME="fsecure">F-Secure</A></H4>
+<UL>
+<LI>
+<!-- <A HREF="http://lists.freeswan.org/pipermail/users/2002-February/007596.html"> -->
+ F-Secure supports IPsec-over-UDP NAT traversal.</LI>
+</UL>
+<P><A HREF="http://www.pingworks.de/tech/vpn/vpn.txt">pingworks.de's
+ &quot;Connecting F-Secure's VPN+ to Linux FreeS/WAN&quot; (PSK road warrior)</A>
+<BR> &nbsp;&nbsp;&nbsp;&nbsp;<A HREF="http://www.pingworks.de/tech/vpn/vpn.pdf">Same thing
+ as PDF</A>
+<BR><A HREF="http://www.exim.org/pipermail/linux-ipsec/Week-of-Mon-20010122/000061.html">
+ Success report, no detail (PSK)</A>
+<BR><A HREF="http://www.exim.org/pipermail/linux-ipsec/Week-of-Mon-20010122/000041.html">
+ Success report, no detail (Manual)</A></P>
+
+<!-- Other NAT traversers:
+http://lists.freeswan.org/pipermail/users/2002-April/009136.html
+and ssh sentinel:
+http://lists.freeswan.org/pipermail/users/2001-September/003108.html
+-->
+<P><A HREF="#fsecure.top">Back to chart</A></P>
+<H4><A NAME="gauntlet">Gauntlet GVPN</A></H4>
+<P><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/11/msg00535.html">
+ Richard Reiner's ipsec.conf (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-June/011434.html">
+ Might work without that pesky firewall... (PSK)</A>
+<BR>
+<!-- insert archive link -->
+ In late July, 2003 Alexandar Antik reported success interoperating
+ with Gauntlet 6.0 for Solaris (X.509). Unfortunately the message is not
+ properly archived at this time.</P>
+<P><A HREF="#gauntlet.top">Back to chart</A></P>
+<H4><A NAME="aix">IBM AIX</A></H4>
+<P><A HREF="http://www-1.ibm.com/servers/esdd/articles/security.html">
+ IBM's &quot;Built-In Network Security with AIX&quot; (PSK, X.509)</A>
+<BR><A HREF="http://www-1.ibm.com/servers/aix/products/ibmsw/security/vpn/faqandtips/#ques20">
+ IBM's tip: importing Linux FreeS/WAN settings into AIX's<VAR> ikedb</VAR>
+ (PSK)</A></P>
+<P><A HREF="#aix.top">Back to chart</A></P>
+<H4><A NAME="as400">IBM AS/400</A></H4>
+<UL>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2002-April/009106.html">
+ Road Warriors may act flaky</A>.</LI>
+</UL>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2002-September/014264.html">
+ Richard Welty's tips and tricks</A>
+<BR></P>
+<P><A HREF="#as400.top">Back to chart</A></P>
+<H4><A NAME="intel">Intel Shiva LANRover / Net Structure</A></H4>
+<UL>
+<LI>Intel Shiva LANRover is now known as Intel Net Structure.</LI>
+<LI><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/01/msg00298.html">
+ Shiva seems to have two modes: IPsec or the proprietary &quot;Shiva Tunnel&quot;.</A>
+ Of course, FreeS/WAN will only create IPsec tunnels.</LI>
+<LI><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/02/msg00293.html">
+ AH may not work for Shiva-FreeS/WAN.</A> That's OK, since FreeS/WAN has
+ phased out the use of AH.</LI>
+</UL>
+<P><A HREF="http://snowcrash.tdyc.com/freeswan/"> Snowcrash's configs
+ (PSK)</A>
+<BR><A HREF="http://www.opus1.com/vpn/index.html"> Old configs from an
+ interop (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2001-October/003831.html">
+ The day Shiva tickled a Pluto bug (PSK)</A>
+<BR> &nbsp;&nbsp;&nbsp;&nbsp;<A HREF="http://lists.freeswan.org/pipermail/users/2001-October/004270.html">
+ Follow up: success!</A></P>
+<P><A HREF="#intel.top">Back to chart</A></P>
+<H4><A NAME="lancom">LanCom (formerly ELSA)</A></H4>
+<UL>
+<LI>This router is popular in Germany.</LI>
+</UL>
+<P> Jakob Curdes successfully created a PSK connection with the LanCom
+ 1612 in August 2003.
+<!-- add ML link when it appears -->
+</P>
+<P><A HREF="#lancom.top">Back to chart</A></P>
+<H4><A NAME="linksys">Linksys</A></H4>
+<UL>
+<LI>Linksys may be used as an IPsec tunnel endpoint,<STRONG> OR</STRONG>
+ as a router in &quot;IPsec passthrough&quot; mode, so that the IPsec tunnel
+ passes through the Linksys.</LI>
+</UL>
+<H5>As tunnel endpoint</H5>
+<P><A HREF="http://www.freeswan.ca/docs/BEFVP41/"> Ken Bantoft's
+ instructions (Road Warrior with PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-February/007814.html">
+ Nate Carlson's caveats</A></P>
+<H5>In IPsec passthrough mode</H5>
+<P><A HREF="http://www-ec.njit.edu/~rxt1077/Howto.txt"> Sample HOWTO
+ through a Linksys Router</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2002/02/msg00114.html">
+ Nadeem Hasan's configs</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2002/02/msg00180.html">
+ Brock Nanson's tips</A>
+<BR></P>
+<P><A HREF="#linksys.top">Back to chart</A></P>
+<H4><A NAME="lucent">Lucent</A></H4>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2002-May/010976.html">
+ Partial success report; see also the next message in thread</A></P>
+
+<!-- section done -->
+<P><A HREF="#lucent.top">Back to chart</A></P>
+<H4><A NAME="netasq">Netasq</A></H4>
+<P><A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+ French page with configs (X.509)</A></P>
+
+<!-- section done -->
+<P><A HREF="#netasq.top">Back to chart</A></P>
+<H4><A NAME="netcelo">Netcelo</A></H4>
+<P><A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+ French page with configs (X.509)</A>
+<!-- section done -->
+</P>
+<P><A HREF="#netcelo.top">Back to chart</A></P>
+<H4><A NAME="netgear">Netgear fvs318</A></H4>
+<UL>
+<LI>With a recent Linux FreeS/WAN, you will require the latest (12/2002)
+ Netgear firmware, which supports Diffie-Hellman (DH) group 2. For
+ security reasons, we phased out DH 1 after Linux FreeS/WAN 1.5.</LI>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2002-June/011833.html">
+ This message</A> reports the incompatibility between Linux FreeS/WAN
+ 1.6+ and Netgear fvs318 without the firmware upgrade.</LI>
+<LI>We believe Linux FreeS/WAN 1.5 and earlier will interoperate with
+ any NetGear firmware.</LI>
+</UL>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2003-February/017891.html">
+ John Morris' setup (PSK)</A></P>
+<P><A HREF="#netgear.top">Back to chart</A></P>
+<H4><A NAME="netscreen">Netscreen 100 or 5xp</A></H4>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2002-August/013409.html">
+ Errol Neal's settings (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-October/015265.html">
+ Corey Rogers' configs (PSK, no PFS)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-August/013051.html">
+ Jordan Share's configs (PSK, 2 subnets, through static NAT)</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/08/msg00404.html">
+ Set src proxy_id to your protected subnet/mask</A>
+<BR><A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+ French page with ipsec.conf, Netscreen screen shots (X.509, may need to
+ revert to PSK...)</A></P>
+<P><A HREF="http://archives.neohapsis.com/archives/sf/linux/2001-q2/0123.html">
+ A report of a company using Netscreen with FreeS/WAN on a large scale
+ (FreeS/WAN road warriors?)</A></P>
+<P><A HREF="#netscreen.top">Back to chart</A></P>
+<H4><A NAME="nortel">Nortel Contivity</A></H4>
+<UL>
+<LI> Nortel supports IPsec-over-UDP NAT traversal.</LI>
+<LI><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/02/msg00417.html">
+ Some older versions of Contivity and FreeS/WAN will not communicate.</A>
+</LI>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2002-May/010924.html">
+ FreeS/WAN cannot be used as a &quot;client&quot; to a Nortel Contivity server,
+ but can be used as a branch-office tunnel.</A></LI>
+
+<!--  Probably obsoleted by Ken's post
+<LI>
+(Matthias siebler from old interop)
+At one point you could not configure Nortel-FreeS/WAN tunnels as 
+"Client Tunnels" since FreeS/WAN does not support Aggressive Mode.
+Current status of this problem: unknown.
+<LI>
+<A HREF="http://lists.freeswan.org/pipermail/users/2001-November/004612.html">
+How do we map group and user passwords onto the data that FreeS/WAN wants?
+</A>
+</LI>
+-->
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2002-October/015455.html">
+ Contivity does not send Distinguished Names in the order FS wants them
+ (X.509).</A></LI>
+<LI><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/03/msg00137.html">
+ Connections may time out after 30-40 minutes idle.</A></LI>
+</UL>
+<P><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/03/msg00137.html">
+ JJ Streicher-Bremer's mini HOWTO for old new software. (PSK with two
+ subnets)</A>
+<BR><A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+ French page with configs (X.509)</A>. This succeeds using the above
+ X.509 tip.</P>
+
+<!-- I could do more searching but this is a solid start. -->
+<P><A HREF="#nortel.top">Back to chart</A></P>
+<H4><A NAME="radguard">Radguard</A></H4>
+<P><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/05/msg00009.html">
+ Marko Hausalo's configs (PSK).</A> Note: These do create a connection,
+ as you can see by &quot;IPsec SA established&quot;.
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-October/???.html">
+ Claudia Schmeing's comments</A></P>
+<P><A HREF="#radguard.top">Back to chart</A></P>
+<H4><A NAME="raptor">Raptor (NT or Solaris)</A></H4>
+<P></P>
+<UL>
+<LI>Now known as Symantec Enterprise Firewall.</LI>
+<LI>The Raptor does not normally come with X.509, but this may be
+ available as an add-on.</LI>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2002-May/010256.html">
+ Raptor requires alphanumberic PSK values, whereas FreeS/WAN uses hex.</A>
+</LI>
+<LI>Raptor's tunnel endpoint may be a host, subnet or group of subnets
+ (see<A HREF="http://lists.freeswan.org/pipermail/design/2001-November/001295.html">
+ this message</A> ). FreeS/WAN cannot handle the group of subnets; you
+ must create separate connections for each in order to interoperate.</LI>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2002-May/010113.html">
+ Some versions of Raptor accept only single DES.</A> According to this
+ German message,<A HREF="http://radawana.cg.tuwien.ac.at/mail-archives/lll/200012/msg00065.html">
+ the Raptor Mobile Client demo offers single DES only.</A></LI>
+</UL>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2002-January/006935.html">
+ Peter Mazinger's settings (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2001-November/005522.html">
+ Peter Gerland's configs (PSK)</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/07/msg00597.html">
+ Charles Griebel's configs (PSK).</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-July/012275.html">
+ Lumir Srch's tips (PSK)</A></P>
+<P><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/05/msg00214.html">
+ John Hardy's configs (Manual)</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/01/msg00236.html">
+ Older Raptors want 3DES keys in 3 parts (Manual).</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/06/msg00480.html">
+ Different keys for each direction? (Manual)</A>
+<BR></P>
+<P><A HREF="#raptor.top">Back to chart</A></P>
+<H4><A NAME="redcreek">Redcreek Ravlin</A></H4>
+<UL>
+<LI>Known issue #1: The Ravlin expects a quick mode renegotiation right
+ after every Main Mode negotiation.</LI>
+<LI> Known issue #2: The Ravlin tries to negotiate a zero connection
+ lifetime, which it takes to mean &quot;infinite&quot;.<A HREF="http://www.bear-cave.org.uk/linux/ravlin/">
+ Jim Hague's patch</A> addresses both issues.</LI>
+<LI><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/03/msg00191.html">
+ Interop works with Ravlin Firmware &gt; 3.33. Includes tips (PSK).</A></LI>
+</UL>
+<P><A HREF="#redcreek.top">Back to chart</A></P>
+<H4><A NAME="sonicwall">SonicWall</A></H4>
+<UL>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2001-June/000998.html">
+ Sonicwall cannot be used for Road Warrior setups</A></LI>
+<LI> At one point,<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/05/msg00217.html">
+ only Sonicwall PRO supported triple DES</A>.</LI>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2002-March/008600.html">
+ Older Sonicwalls (before Nov 2001) feature Diffie Hellman group 1 only</A>
+.</LI>
+</UL>
+<P><A HREF="http://www.xinit.cx/docs/freeswan.html"> Paul Wouters'
+ config (PSK)</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/02/msg00073.html">
+ Dilan Arumainathan's configuration (PSK)</A>
+<BR><A HREF="http://www.gravitas.co.uk/vpndebug"> Dariush's setup...
+ only opens one way (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2003-July/022302.html">
+ Andreas Steffen's tips (X.509)</A>
+<BR></P>
+<P><A HREF="#sonicwall.top">Back to chart</A></P>
+<H4><A NAME="sun">Sun Solaris</A></H4>
+<UL>
+<LI> Solaris 8+ has a native (in kernel) IPsec implementation.</LI>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2002-May/010503.html">
+ Solaris does not seem to support tunnel mode, but you can make IP-in-IP
+ tunnels instead, like this.</A></LI>
+</UL>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2003-June/022216.html">
+ Reports of some successful interops</A> from a fellow @sun.com. See
+ also<A HREF="http://lists.freeswan.org/pipermail/users/2003-July/022247.html">
+ these follow up posts</A>.
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/03/msg00332.html">
+ Aleks Shenkman's configs (Manual in transport mode)</A>
+<BR>
+<!--sparc 64 stuff goes where?-->
+</P>
+<P><A HREF="#solaris.top">Back to chart</A></P>
+<H4><A NAME="symantec">Symantec</A></H4>
+<UL>
+<LI>The Raptor, covered<A HREF="#raptor"> above</A>, is now known as
+ Symantec Enterprise Firewall.</LI>
+<LI>Symantec's &quot;distinguished name&quot; is a KEY_ID. See Andreas Steffen's
+ post, below.</LI>
+</UL>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2002-April/009037.html">
+ Andreas Steffen's configs for Symantec 200R (PSK)</A></P>
+<P><A HREF="#symantec.top">Back to chart</A></P>
+<H4><A NAME="watchguard">Watchguard Firebox</A></H4>
+<UL>
+<LI>Automatic keying works with WatchGuard 5.0+ only.</LI>
+<LI>Seen to interoperate with WatchGuard 1000, II, III; firmware v. 5,
+ 6..</LI>
+<LI>For manual keying, Watchguard's Policy Manager expects SPI numbers
+ and encryption and authentication keys in decimal (not hex).</LI>
+</UL>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2002-July/012595.html">
+ WatchGuard's HOWTO (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-August/013342.html">
+ Ronald C. Riviera's Settings (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/archives/users/2003-October/msg00179.html">
+ Walter Wickersham's Notes (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-October/015587.html">
+ Max Enders' Configs (Manual)</A></P>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2002-April/009404.html">
+ Old known issue with auto keying</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/02/msg00124.html">
+ Tips on key generation and format (Manual)</A>
+<BR></P>
+<P><A HREF="#watchguard.top">Back to chart</A></P>
+<H4><A NAME="xedia">Xedia Access Point/QVPN</A></H4>
+<P><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/12/msg00520.html">
+ Hybrid IPsec/L2TP connection settings (X.509)</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/ipsec/1999/08/msg00140.html">
+ Xedia's LAN-LAN links don't use multiple tunnels</A>
+<BR> &nbsp;&nbsp;&nbsp;&nbsp;<A HREF="http://www.sandelman.ottawa.on.ca/ipsec/1999/08/msg00140.html">
+ That explanation, continued</A></P>
+<P><A HREF="#xedia.top">Back to chart</A></P>
+<H4><A NAME="zyxel">Zyxel</A></H4>
+<UL>
+<LI>The Zyxel Zywall is a rebranded SSH Sentinel box. See also our
+ section on<A HREF="#ssh"> SSH</A>.</LI>
+<LI>There seems to be a problem with keeping this connection alive. This
+ is caused at the Zyxel end. See this brief<A HREF="http://lists.freeswan.org/archives/users/2003-October/msg00141.html">
+ discussion and solution.</A></LI>
+</UL>
+<P><A HREF="http://www.zyxel.com/support/supportnote/zywall/app/zw_freeswan.htm">
+ Zyxel's Zywall to FreeS/WAN instructions (PSK)</A>
+<BR><A HREF="http://www.zyxel.com/support/supportnote/p652/app/zw_freeswan.htm">
+ Zyxel's Prestige to FreeS/WAN instructions (PSK)</A>. Note: not all
+ Prestige versions include VPN software.
+<BR><A HREF="http://www.lancry.net/techdocs/freeswan-zyxel.txt"> Fabrice
+ Cahen's HOWTO (PSK)</A>
+<BR> &nbsp;&nbsp;&nbsp;&nbsp;</P>
+<P><A HREF="#zyxel.top">Back to chart</A></P>
+
+<!-- SAMPLE ENTRY
+
+<H4><A NAME="timestep">Timestep</A></H4>
+
+<P>Text goes here.
+</P>
+
+-->
+<HR>
+<H1><A name="performance">Performance of FreeS/WAN</A></H1>
+ The performance of FreeS/WAN is adequate for most applications.
+<P>In normal operation, the main concern is the overhead for encryption,
+ decryption and authentication of the actual IPsec (<A href="#ESP">ESP</A>
+ and/or<A href="#AH"> AH</A>) data packets. Tunnel setup and rekeying
+ occur so much less frequently than packet processing that, in general,
+ their overheads are not worth worrying about.</P>
+<P>At startup, however, tunnel setup overheads may be significant. If
+ you reboot a gateway and it needs to establish many tunnels, expect
+ some delay. This and other issues for large gateways are discussed<A href="#biggate">
+ below</A>.</P>
+<H2><A name="pub.bench">Published material</A></H2>
+<P>The University of Wales at Aberystwyth has done quite detailed speed
+ tests and put<A href="http://tsc.llwybr.org.uk/public/reports/SWANTIME/">
+ their results</A> on the web.</P>
+<P>Davide Cerri's<A href="http://www.linux.it/~davide/doc/"> thesis (in
+ Italian)</A> includes performance results for FreeS/WAN and for<A href="#TLS">
+ TLS</A>. He posted an<A href="http://lists.freeswan.org/pipermail/users/2001-December/006303.html">
+ English summary</A> on the mailing list.</P>
+<P>Steve Bellovin used one of AT&amp;T Research's FreeS/WAN gateways as his
+ data source for an analysis of the cache sizes required for key
+ swapping in IPsec. Available as<A href="http://www.research.att.com/~smb/talks/key-agility.email.txt">
+ text</A> or<A href="http://www.research.att.com/~smb/talks/key-agility.pdf">
+ PDF slides</A> for a talk on the topic.</P>
+<P>See also the NAI work mentioned in the next section.</P>
+<H2><A name="perf.estimate">Estimating CPU overheads</A></H2>
+<P>We can come up with a formula that roughly relates CPU speed to the
+ rate of IPsec processing possible. It is far from exact, but should be
+ usable as a first approximation.</P>
+<P>An analysis of authentication overheads for high-speed networks,
+ including some tests using FreeS/WAN, is on the<A href="http://www.pgp.com/research/nailabs/cryptographic/adaptive-cryptographic.asp">
+ NAI Labs site</A>. In particular, see figure 3 in this<A href="http://download.nai.com/products/media/pgp/pdf/acsa_final_report.pdf">
+ PDF document</A>. Their estimates of overheads, measured in Pentium II
+ cycles per byte processed are:</P>
+<TABLE align="center" border="1"><TBODY></TBODY>
+<TR><TH></TH><TH>IPsec</TH><TH>authentication</TH><TH>encryption</TH><TH>
+cycles/byte</TH></TR>
+<TR><TD>Linux IP stack alone</TD><TD>no</TD><TD>no</TD><TD>no</TD><TD align="right">
+5</TD></TR>
+<TR><TD>IPsec without crypto</TD><TD>yes</TD><TD>no</TD><TD>no</TD><TD align="right">
+11</TD></TR>
+<TR><TD>IPsec, authentication only</TD><TD>yes</TD><TD>SHA-1</TD><TD>no</TD><TD
+align="right">24</TD></TR>
+<TR><TD>IPsec with encryption</TD><TD>yes</TD><TD>yes</TD><TD>yes</TD><TD
+align="right">not tested</TD></TR>
+</TABLE>
+<P>Overheads for IPsec with encryption were not tested in the NAI work,
+ but Antoon Bosselaers'<A href="http://www.esat.kuleuven.ac.be/~bosselae/fast.html">
+ web page</A> gives cost for his optimised Triple DES implementation as
+ 928 Pentium cycles per block, or 116 per byte. Adding that to the 24
+ above, we get 140 cycles per byte for IPsec with encryption.</P>
+<P>At 140 cycles per byte, a 140 MHz machine can handle a megabyte -- 8
+ megabits -- per second. Speeds for other machines will be proportional
+ to this. To saturate a link with capacity C megabits per second, you
+ need a machine running at<VAR> C * 140/8 = C * 17.5</VAR> MHz.</P>
+<P>However, that estimate is not precise. It ignores the differences
+ between:</P>
+<UL>
+<LI>NAI's test packets and real traffic</LI>
+<LI>NAI's Pentium II cycles, Bosselaers' Pentium cycles, and your
+ machine's cycles</LI>
+<LI>different 3DES implementations</LI>
+<LI>SHA-1 and MD5</LI>
+</UL>
+<P>and does not account for some overheads you will almost certainly
+ have:</P>
+<UL>
+<LI>communication on the client-side interface</LI>
+<LI>switching between multiple tunnels -- re-keying, cache reloading and
+ so on</LI>
+</UL>
+<P>so we suggest using<VAR> C * 25</VAR> to get an estimate with a bit
+ of a built-in safety factor.</P>
+<P>This covers only IP and IPsec processing. If you have other loads on
+ your gateway -- for example if it is also working as a firewall -- then
+ you will need to add your own safety factor atop that.</P>
+<P>This estimate matches empirical data reasonably well. For example,
+ Metheringham's tests, described<A href="#klips.bench"> below</A>, show
+ a 733 topping out between 32 and 36 Mbit/second, pushing data as fast
+ as it can down a 100 Mbit link. Our formula suggests you need at least
+ an 800 to handle a fully loaded 32 Mbit link. The two results are
+ consistent.</P>
+<P>Some examples using this estimation method:</P>
+<TABLE align="center" border="1"><TBODY></TBODY>
+<TR><TH colspan="2">Interface</TH><TH colspan="3">Machine speed in MHz</TH>
+</TR>
+<TR><TH>Type</TH><TH>Mbit per
+<BR> second</TH><TH>Estimate
+<BR> Mbit*25</TH><TH>Minimum IPSEC gateway</TH><TH>Minimum with other
+ load
+<P>(e.g. firewall)</P>
+</TH></TR>
+<TR><TD>DSL</TD><TD align="right">1</TD><TD align="right">25 MHz</TD><TD rowspan="2">
+whatever you have</TD><TD rowspan="2">133, or better if you have it</TD></TR>
+<TR><TD>cable modem</TD><TD align="right">3</TD><TD align="right">75 MHz</TD>
+</TR>
+<TR><TD><STRONG>any link, light load</STRONG></TD><TD align="right"><STRONG>
+5</STRONG></TD><TD align="right">125 MHz</TD><TD>133</TD><TD>200+,<STRONG>
+ almost any surplus machine</STRONG></TD></TR>
+<TR><TD>Ethernet</TD><TD align="right">10</TD><TD align="right">250 MHz</TD><TD>
+surplus 266 or 300</TD><TD>500+</TD></TR>
+<TR><TD><STRONG>fast link, moderate load</STRONG></TD><TD align="right"><STRONG>
+20</STRONG></TD><TD align="right">500 MHz</TD><TD>500</TD><TD>800+,<STRONG>
+ any current off-the-shelf PC</STRONG></TD></TR>
+<TR><TD>T3 or E3</TD><TD align="right">45</TD><TD align="right">1125 MHz</TD><TD>
+1200</TD><TD>1500+</TD></TR>
+<TR><TD>fast Ethernet</TD><TD align="right">100</TD><TD align="right">
+2500 MHz</TD><TD align="center" colspan="2" rowspan="2">// not feasible
+ with 3DES in software on current machines //</TD></TR>
+<TR><TD>OC3</TD><TD align="right">155</TD><TD align="right">3875 MHz</TD>
+</TR>
+</TABLE>
+<P>Such an estimate is far from exact, but should be usable as minimum
+ requirement for planning. The key observations are:</P>
+<UL>
+<LI>older<STRONG> surplus machines</STRONG> are fine for IPsec gateways
+ at loads up to<STRONG> 5 megabits per second</STRONG> or so</LI>
+<LI>a<STRONG> mid-range new machine</STRONG> can handle IPsec at rates
+ up to<STRONG> 20 megabits per second</STRONG> or more</LI>
+</UL>
+<H3><A name="perf.more">Higher performance alternatives</A></H3>
+<P><A href="#AES">AES</A> is a new US government block cipher standard,
+ designed to replace the obsolete<A href="#DES"> DES</A>. If FreeS/WAN
+ using<A href="#3DES"> 3DES</A> is not fast enough for your application,
+ the AES<A href="#patch"> patch</A> may help.</P>
+<P>To date (March 2002) we have had only one<A href="http://lists.freeswan.org/pipermail/users/2002-February/007771.html">
+ mailing list report</A> of measurements with the patch applied. It
+ indicates that, at least for the tested load on that user's network,<STRONG>
+ AES roughly doubles IPsec throughput</STRONG>. If further testing
+ confirms this, it may prove possible to saturate an OC3 link in
+ software on a high-end box.</P>
+<P>Also, some work is being done toward support of<A href="#hardware">
+ hardware IPsec acceleration</A> which might extend the range of
+ requirements FreeS/WAN could meet.</P>
+<H3><A NAME="11_2_2">Other considerations</A></H3>
+<P>CPU speed may be the main issue for IPsec performance, but of course
+ it isn't the only one.</P>
+<P>You need good ethernet cards or other network interface hardware to
+ get the best performance. See this<A href="http://www.ethermanage.com/ethernet/ethernet.html">
+ ethernet information</A> page and this<A href="http://www.scyld.com/diag">
+ Linux network driver</A> page.</P>
+<P>The current FreeS/WAN kernel code is largely single-threaded. It is
+ SMP safe, and will run just fine on a multiprocessor machine (<A href="#multiprocessor">
+discussion</A>), but the load within the kernel is not shared
+ effectively. This means that, for example to saturate a T3 -- which
+ needs about a 1200 MHz machine -- you cannot expect something like a
+ dual 800 to do the job.</P>
+<P>On the other hand, SMP machines do tend to share loads well so --
+ provided one CPU is fast enough for the IPsec work -- a multiprocessor
+ machine may be ideal for a gateway with a mixed load.</P>
+<H2><A name="biggate">Many tunnels from a single gateway</A></H2>
+<P>FreeS/WAN allows a single gateway machine to build tunnels to many
+ others. There may, however, be some problems for large numbers as
+ indicated in this message from the mailing list:</P>
+<PRE>Subject: Re: Maximum number of ipsec tunnels?
+   Date: Tue, 18 Apr 2000
+   From: &quot;John S. Denker&quot; &lt;jsd@research.att.com&gt;
+
+Christopher Ferris wrote:
+
+&gt;&gt; What are the maximum number ipsec tunnels FreeS/WAN can handle??
+
+Henry Spencer wrote:
+
+&gt;There is no particular limit.  Some of the setup procedures currently
+&gt;scale poorly to large numbers of connections, but there are (clumsy)
+&gt;workarounds for that now, and proper fixes are coming.
+
+1) &quot;Large&quot; numbers means anything over 50 or so.  I routinely run boxes
+with about 200 tunnels.  Once you get more than 50 or so, you need to worry
+about several scalability issues:
+
+a) You need to put a &quot;-&quot; sign in syslogd.conf, and rotate the logs daily
+not weekly.
+
+b) Processor load per tunnel is small unless the tunnel is not up, in which
+case a new half-key gets generated every 90 seconds, which can add up if
+you've got a lot of down tunnels.
+
+c) There's other bits of lore you need when running a large number of
+tunnels.  For instance, systematically keeping the .conf file free of
+conflicts requires tools that aren't shipped with the standard freeswan
+package.
+
+d) The pluto startup behavior is quadratic.  With 200 tunnels, this eats up
+several minutes at every restart.   I'm told fixes are coming soon.
+
+2) Other than item (1b), the CPU load depends mainly on the size of the
+pipe attached, not on the number of tunnels.
+</PRE>
+<P>It is worth noting that item (1b) applies only to repeated attempts
+ to re-key a data connection (IPsec SA, Phase 2) over an established
+ keying connection (ISAKMP SA, Phase 1). There are two ways to reduce
+ this overhead using settings in<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A>:</P>
+<UL>
+<LI>set<VAR> keyingtries</VAR> to some small value to limit repetitions</LI>
+<LI>set<VAR> keylife</VAR> to a short time so that a failing data
+ connection will be cleaned up when the keying connection is reset.</LI>
+</UL>
+<P>The overheads for establishing keying connections (ISAKMP SAs, Phase
+ 1) are lower because for these Pluto does not perform expensive
+ operations before receiving a reply from the peer.</P>
+<P>A gateway that does a lot of rekeying -- many tunnels and/or low
+ settings for tunnel lifetimes -- will also need a lot of<A href="#random">
+ random numbers</A> from the random(4) driver.</P>
+<H2><A name="low-end">Low-end systems</A></H2>
+<P><EM>Even a 486 can handle a T1 line</EM>, according to this mailing
+ list message:</P>
+<PRE>Subject: Re: linux-ipsec: IPSec Masquerade
+   Date: Fri, 15 Jan 1999 11:13:22 -0500
+   From: Michael Richardson 
+
+. . . A 486/66 has been clocked by Phil Karn to do
+10Mb/s encryption.. that uses all the CPU, so half that to get some CPU,
+and you have 5Mb/s. 1/3 that for 3DES and you get 1.6Mb/s....</PRE>
+<P>and a piece of mail from project technical lead Henry Spencer:</P>
+<PRE>Oh yes, and a new timing point for Sandy's docs...  A P60 -- yes, a 60MHz
+Pentium, talk about antiques -- running a host-to-host tunnel to another
+machine shows an FTP throughput (that is, end-to-end results with a real
+protocol) of slightly over 5Mbit/s either way.  (The other machine is much
+faster, the network is 100Mbps, and the ether cards are good ones... so
+the P60 is pretty definitely the bottleneck.)</PRE>
+<P>From the above, and from general user experience as reported on the
+ list, it seems clear that a cheap surplus machine -- a reasonable 486,
+ a minimal Pentium box, a Sparc 5, ... -- can easily handle a home
+ office or a small company connection using any of:</P>
+<UL>
+<LI>ADSL service</LI>
+<LI>cable modem</LI>
+<LI>T1</LI>
+<LI>E1</LI>
+</UL>
+<P>If available, we suggest using a Pentium 133 or better. This should
+ ensure that, even under maximum load, IPsec will use less than half the
+ CPU cycles. You then have enough left for other things you may want on
+ your gateway -- firewalling, web caching, DNS and such.</P>
+<H2><A name="klips.bench">Measuring KLIPS</A></H2>
+<P>Here is some additional data from the mailing list.</P>
+<PRE>Subject: FreeSWAN (specically KLIPS) performance measurements
+   Date: Thu, 01 Feb 2001
+   From: Nigel Metheringham &lt;Nigel.Metheringham@intechnology.co.uk&gt;
+
+I've spent a happy morning attempting performance tests against KLIPS 
+(this is due to me not being able to work out the CPU usage of KLIPS so 
+resorting to the crude measurements of maximum throughput to give a 
+baseline to work out loading of a box).
+
+Measurements were done using a set of 4 boxes arranged in a line, each 
+connected to the next by 100Mbit duplex ethernet.  The inner 2 had an 
+ipsec tunnel between them (shared secret, but I was doing measurements 
+when the tunnel was up and running - keying should not be an issue 
+here).  The outer pair of boxes were traffic generators or traffic sink.
+
+The crypt boxes are Compaq DL380s - Uniprocessor PIII/733 with 256K 
+cache.  They have 128M main memory.  Nothing significant was running on 
+the boxes other than freeswan.  The kernel was a 2.2.19pre7 patched 
+with freeswan and ext3.
+
+Without an ipsec tunnel in the chain (ie the 2 inner boxes just being 
+100BaseT routers), throughput (measured with ttcp) was between 10644 
+and 11320 KB/sec
+
+With an ipsec tunnel in place, throughput was between 3268 and 3402 
+KB/sec
+
+These measurements are for data pushed across a TCP link, so the 
+traffic on the wire between the 2 ipsec boxes would have been higher 
+than this....
+
+vmstat (run during some other tests, so not affecting those figures) on 
+the encrypting box shows approx 50% system &amp; 50% idle CPU - which I 
+don't believe at all.  Interactive feel of the box was significantly 
+sluggish.
+
+I also tried running the kernel profiler (see man readprofile) during 
+test runs.
+
+A box doing primarily decrypt work showed basically nothing happening - 
+I assume interrupts were off.
+A box doing encrypt work showed the following:-
+ Ticks Function                                   Load
+ ~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~    ~~~~~~
+   956 total                                      0.0010
+   532 des_encrypt2                               0.1330
+   110 MD5Transform                               0.0443
+    97 kmalloc                                    0.1880
+    39 des_encrypt3                               0.1336
+    23 speedo_interrupt                           0.0298
+    14 skb_copy_expand                            0.0250
+    13 ipsec_tunnel_start_xmit                    0.0009
+    13 Decode                                     0.1625
+    11 handle_IRQ_event                           0.1019
+    11 .des_ncbc_encrypt_end                      0.0229
+    10 speedo_start_xmit                          0.0188
+     9 satoa                                      0.0225
+     8 kfree                                      0.0118
+     8 ip_fragment                                0.0121
+     7 ultoa                                      0.0365
+     5 speedo_rx                                  0.0071
+     5 .des_encrypt2_end                          5.0000
+     4 _stext                                     0.0140
+     4 ip_fw_check                                0.0035
+     2 rj_match                                   0.0034
+     2 ipfw_output_check                          0.0200
+     2 inet_addr_type                             0.0156
+     2 eth_copy_and_sum                           0.0139
+     2 dev_get                                    0.0294
+     2 addrtoa                                    0.0143
+     1 speedo_tx_buffer_gc                        0.0024
+     1 speedo_refill_rx_buf                       0.0022
+     1 restore_all                                0.0667
+     1 number                                     0.0020
+     1 net_bh                                     0.0021
+     1 neigh_connected_output                     0.0076
+     1 MD5Final                                   0.0083
+     1 kmem_cache_free                            0.0016
+     1 kmem_cache_alloc                           0.0022
+     1 __kfree_skb                                0.0060
+     1 ipsec_rcv                                  0.0001
+     1 ip_rcv                                     0.0014
+     1 ip_options_fragment                        0.0071
+     1 ip_local_deliver                           0.0023
+     1 ipfw_forward_check                         0.0139
+     1 ip_forward                                 0.0011
+     1 eth_header                                 0.0040
+     1 .des_encrypt3_end                          0.0833
+     1 des_decrypt3                               0.0034
+     1 csum_partial_copy_generic                  0.0045
+     1 call_out_firewall                          0.0125
+
+Hope this data is helpful to someone... however the lack of visibility 
+into the decrypt side makes things less clear</PRE>
+<H2><A name="speed.compress">Speed with compression</A></H2>
+<P>Another user reported some results for connections with and without
+ IP compression:</P>
+<PRE>Subject: [Users] Speed with compression
+   Date: Fri, 29 Jun 2001
+   From: John McMonagle &lt;johnm@advocap.org&gt;
+
+Did a couple tests with compression using the new 1.91 freeswan.
+
+Running between 2 sites with cable modems.  Both  using approximately
+130 mhz pentium.
+
+Transferred files with ncftp.
+
+Compressed file was a 6mb compressed  installation file.
+Non compressed was 18mb /var/lib/rpm/packages.rpm
+
+                            Compressed vpn          regular vpn
+Compress file                42.59 kBs               42.08 kBs
+regular file                110.84 kBs               41.66 kBs
+
+Load  was about 0 either way.
+Ping times were very similar  a bit above 9 ms.
+
+Compression looks attractive to me.</PRE>
+ Later in the same thread, project technical lead Henry Spencer added:
+<PRE>&gt; is there a reason not to switch compression on?  I have large gateway boxes
+&gt; connecting 3 connections, one of them with a measly DS1 link...
+
+Run some timing tests with and without, with data and loads representative
+of what you expect in production.  That's the definitive way to decide. 
+If compression is a net loss, then obviously, leave it turned off.  If it
+doesn't make much difference, leave it off for simplicity and hence
+robustness.  If there's a substantial gain, by all means turn it on. 
+
+If both ends support compression and can successfully negotiate a
+compressed connection (trivially true if both are FreeS/WAN 1.91), then
+the crucial question is CPU cycles. 
+
+Compression has some overhead, so one question is whether *your* data
+compresses well enough to save you more CPU cycles (by reducing the volume
+of data going through CPU-intensive encryption/decryption) than it costs
+you.  Last time I ran such tests on data that was reasonably compressible
+but not deliberately contrived to be so, this generally was not true --
+compression cost extra CPU cycles -- so compression was worthwhile only if
+the link, not the CPU, was the bottleneck.  However, that was before the
+slow-compression bug was fixed.  I haven't had a chance to re-run those
+tests yet, but it sounds like I'd probably see a different result. </PRE>
+ The bug he refers to was a problem with the compression libraries that
+ had us using C code, rather than assembler, for compression. It was
+ fixed before 1.91.
+<H2><A name="methods">Methods of measuring</A></H2>
+<P>If you want to measure the loads FreeS/WAN puts on a system, note
+ that tools such as top or measurements such as load average are
+ more-or-less useless for this. They are not designed to measure
+ something that does most of its work inside the kernel.</P>
+<P>Here is a message from FreeS/WAN kernel programmer Richard Guy Briggs
+ on this:</P>
+<PRE>&gt; I have a batch of boxes doing Freeswan stuff.
+&gt; I want to measure the CPU loading of the Freeswan tunnels, but am 
+&gt; having trouble seeing how I get some figures out...
+&gt; 
+&gt;  - Keying etc is in userspace so will show up on the per-process
+&gt;    and load average etc (ie pluto's load)
+
+Correct.
+
+&gt;  - KLIPS is in the kernel space, and does not show up in load average
+&gt;    I think also that the KLIPS per-packet processing stuff is running
+&gt;    as part of an interrupt handler so it does not show up in the
+&gt;    /proc/stat system_cpu or even idle_cpu figures
+
+It is not running in interrupt handler.  It is in the bottom half.
+This is somewhere between user context (careful, this is not
+userspace!) and hardware interrupt context.
+
+&gt; Is this correct, and is there any means of instrumenting how much the 
+&gt; cpu is being loaded - I don't like the idea of a system running out of 
+&gt; steam whilst still showing 100% idle CPU :-)
+
+vmstat seems to do a fairly good job, but use a running tally to get a
+good idea.  A one-off call to vmstat gives different numbers than a
+running stat.  To do this, put an interval on your vmstat command
+line.</PRE>
+ and another suggestion from the same thread:
+<PRE>Subject: Re: Measuring the CPU usage of Freeswan
+   Date: Mon, 29 Jan 2001
+   From: Patrick Michael Kane &lt;modus@pr.es.to&gt;
+ 
+The only truly accurate way to accurately track FreeSWAN CPU usage is to use
+a CPU soaker. You run it on an unloaded system as a benchmark, then start up
+FreeSWAN and take the difference to determine how much FreeSWAN is eating.
+I believe someone has done this in the past, so you may find something in
+the FreeSWAN archives.  If not, someone recently posted a URL to a CPU
+soaker benchmark tool on linux-kernel.</PRE>
+<HR>
+<H1><A name="test.freeswan">Testing FreeS/WAN</A></H1>
+ This document discusses testing FreeS/WAN.
+<P>Not all types of testing are described here. Other parts of the
+ documentation describe some tests:</P>
+<DL>
+<DT><A href="#testinstall">installation</A> document</DT>
+<DD>testing for a successful install</DD>
+<DT><A href="config.html#testsetup">configuration</A> document</DT>
+<DD>basic tests for a working configuration</DD>
+<DT><A href="#interop.web">web links</A> document</DT>
+<DD>General information on tests for interoperability between various
+ IPsec implementations. This includes links to several test sites.</DD>
+<DT><A href="interop.html">interoperation</A> document.</DT>
+<DD>More specific information on FreeS/WAN interoperation with other
+ implementations.</DD>
+<DT><A href="performance.html">performance</A> document</DT>
+<DD>performance measurements</DD>
+</DL>
+<P>The test setups and procedures described here can also be used in
+ other testing, but this document focuses on testing the IPsec
+ functionality of FreeS/WAN.</P>
+<H2><A NAME="test.oe">Testing opportunistic connections</A></H2>
+<P>This section teaches you how to test your opportunistically encrypted
+ (OE) connections. To set up OE, please see the easy instructions in our<A
+HREF="quickstart.html"> quickstart guide</A>.</P>
+<H3><A NAME="12_1_1">Basic OE Test</A></H3>
+<P>This test is for basic OE functionality.
+<!-- You may use it on an 
+<A HREF="quickstart.html#oppo.client">initiate-only OE</A> box or a 
+<A HREF="quickstart.html#opp.incoming">full OE</A> box. -->
+ For additional tests, keep
+ reading.</P>
+<P>Be sure IPsec is running. You can see whether it is with:</P>
+<PRE>    ipsec setup status</PRE>
+<P>If need be, you can restart it with:</P>
+<PRE>    service ipsec restart</PRE>
+<P>Load a FreeS/WAN test website from the host on which you're running
+ FreeS/WAN. Note: the feds may be watching these sites. Type one of:</P>
+<P></P>
+<PRE>   links oetest.freeswan.org</PRE>
+<PRE>   links oetest.freeswan.nl</PRE>
+
+<!--<PRE>   links oetest.freeswan.ca</PRE>-->
+<P>A positive result looks like this:</P>
+<PRE>
+   You  seem  to  be  connecting  from:  192.0.2.11 which DNS says is:
+   gateway.example.com
+     _________________________________________________________________
+                                                                                
+   Status E-route
+   OE    enabled    16    192.139.46.73/32    -&gt;    192.0.2.11/32   =&gt;
+   tun0x2097@192.0.2.11
+   OE    enabled    176    192.139.46.77/32    -&gt;   192.0.2.11/32   =&gt;
+   tun0x208a@192.0.2.11
+</PRE>
+<P>If you see this, congratulations! Your OE box will now encrypt its
+ own traffic whenever it can. If you have difficulty, see our<A HREF="#oe.trouble">
+ OE troubleshooting tips</A>.</P>
+<H3><A NAME="12_1_2">OE Gateway Test</A></H3>
+<P>If you've set up FreeS/WAN to protect a subnet behind your gateway,
+ you'll need to run another simple test, which can be done from a
+ machine running any OS. That's right, your Windows box can be protected
+ by opportunistic encryption without any FreeS/WAN install or
+ configuration on that box. From<STRONG> each protected subnet node</STRONG>
+, load the FreeS/WAN website with:</P>
+<PRE>   links oetest.freeswan.org</PRE>
+<PRE>   links oetest.freeswan.nl</PRE>
+<P>A positive result looks like this:</P>
+<PRE>
+   You  seem  to  be  connecting  from:  192.0.2.98 which DNS says is:
+   box98.example.com
+     _________________________________________________________________
+                                                                                
+   Status E-route
+   OE    enabled    16    192.139.46.73/32    -&gt;    192.0.2.98/32   =&gt;
+   tun0x134ed@192.0.2.11
+   OE    enabled    176    192.139.46.77/32    -&gt;   192.0.2.11/32   =&gt;
+   tun0x134d2@192.0.2.11
+</PRE>
+<P>If you see this, congratulations! Your OE gateway will now encrypt
+ traffic for this subnet node whenever it can. If you have difficulty,
+ see our<A HREF="#oe.trouble"> OE troubleshooting tips</A>.</P>
+<H3><A NAME="12_1_3">Additional OE tests</A></H3>
+<P>When testing OE, you will often find it useful to execute this
+ command on the FreeS/WAN host:</P>
+<PRE>   ipsec eroute</PRE>
+<P>If you have established a connection (either for or for a subnet
+ node) you will see a result like:</P>
+<PRE>    192.0.2.11/32   -&gt; 192.139.46.73/32  =&gt; tun0x149f@192.139.46.38
+</PRE>
+<P>Key:</P>
+<TABLE>
+<TR><TD>1.</TD><TD>192.0.2.11/32</TD><TD>Local start point of the
+ protected traffic.</TD></TR>
+<TR><TD>2.</TD><TD>192.0.2.194/32</TD><TD>Remote end point of the
+ protected traffic.</TD></TR>
+<TR><TD>3.</TD><TD>192.0.48.38</TD><TD>Remote FreeS/WAN node (gateway or
+ host). May be the same as (2).</TD></TR>
+<TR><TD>4.</TD><TD>[not shown]</TD><TD>Local FreeS/WAN node (gateway or
+ host), where you've produced the output. May be the same as (1).</TD></TR>
+</TABLE>
+<P>For extra assurance, you may wish to use a packet sniffer such as<A HREF="http://www.tcpdump.org">
+ tcpdump</A> to verify that packets are being encrypted. You should see
+ output that indicates<STRONG> ESP</STRONG> encrypted data, for example:</P>
+<PRE>    02:17:47.353750 PPPoE  [ses 0x1e12] IP 154: xy.example.com &gt; oetest.freeswan.org: ESP(spi=0x87150d16,seq=0x55)</PRE>
+<H2><A name="test.uml">Testing with User Mode Linux</A></H2>
+<P><A href="http://user-mode-linux.sourceforge.net/">User Mode Linux</A>
+ allows you to run Linux as a user process on another Linux machine.</P>
+<P>As of 1.92, the distribution has a new directory named testing. It
+ contains a collection of test scripts and sample configurations. Using
+ these, you can bring up several copies of Linux in user mode and have
+ them build tunnels to each other. This lets you do some testing of a
+ FreeS/WAN configuration on a single machine.</P>
+<P>You need a moderately well-endowed machine for this to work well.
+ Each UML wants about 16 megs of memory by default, which is plenty for
+ FreeS/WAN usage. Typical regression testing only occasionally uses as
+ many as 4 UMLs. If one is doing nothing else with the machine (in
+ particular, not running X on it), then 128 megs and a 500MHz CPU are
+ fine.</P>
+ Documentation on these scripts is<A href="umltesting.html"> here</A>.
+ There is also documentation on automated testing<A href="makecheck.html">
+ here</A>.
+<H2><A name="testnet">Configuration for a testbed network</A></H2>
+<P>A common test setup is to put a machine with dual Ethernet cards in
+ between two gateways under test. You need at least five machines; two
+ gateways, two clients and a testing machine in the middle.</P>
+<P>The central machine both routes packets and provides a place to run
+ diagnostic software for checking IPsec packets. See next section for
+ discussion of<A href="#tcpdump.faq"> using tcpdump(8)</A> for this.</P>
+<P>This makes things more complicated than if you just connected the two
+ gateway machines directly to each other, but it also makes your test
+ setup much more like the environment you actually use IPsec in. Those
+ environments nearly always involve routing, and quite a few apparent
+ IPsec failures turn out to be problems with routing or with firewalls
+ dropping packets. This approach lets you deal with those problems on
+ your test setup.</P>
+<P>What you end up with looks like:</P>
+<H3><A name="testbed">Testbed network</A></H3>
+<PRE>      subnet a.b.c.0/24
+             |
+      eth1 = a.b.c.1
+         gate1
+      eth0 = 192.168.p.1
+             |
+             |
+      eth0 = 192.168.p.2
+         route/monitor box
+      eth1 = 192.168.q.2
+             |
+             |
+      eth0 = 192.168.q.1
+         gate2
+      eth1 = x.y.z.1
+              |
+       subnet x.y.z.0/24</PRE>
+<PRE>Where p and q are any convenient values that do not interfere with other
+routes you may have. The ipsec.conf(5) file then has, among other things:</PRE>
+<PRE>conn abc-xyz
+      left=192.168.p.1
+      leftnexthop=192.168.p.2
+      right=192.168.q.1
+      rightnexthop=192.168.q.2</PRE>
+<P>Once that works, you can remove the &quot;route/monitor box&quot;, and connect
+ the two gateways to the Internet. The only parameters in ipsec.conf(5)
+ that need to change are the four shown above. You replace them with
+ values appropriate for your Internet connection, and change the eth0 IP
+ addresses and the default routes on both gateways.</P>
+<P>Note that nothing on either subnet needs to change. This lets you
+ test most of your IPsec setup before connecting to the insecure
+ Internet.</P>
+<H3><A name="tcpdump.test">Using packet sniffers in testing</A></H3>
+<P>A number of tools are available for looking at packets. We will
+ discuss using<A href="http://www.tcpdump.org/"> tcpdump(8)</A>, a
+ common Linux tool included in most distributions. Alternatives
+ offerring more-or-less the same functionality include:</P>
+<DL>
+<DT><A href="http://www.ethereal.com">Ethereal</A></DT>
+<DD>Several people on our mailing list report a preference for this over
+ tcpdump.</DD>
+<DT><A href="http://netgroup-serv.polito.it/windump/">windump</A></DT>
+<DD>a Windows version of tcpdump(8), possibly handy if you have Windows
+ boxes in your network</DD>
+<DT><A href="http://reptile.rug.ac.be/~coder/sniffit/sniffit.html">
+Sniffit</A></DT>
+<DD>A linux sniffer that we don't know much about. If you use it, please
+ comment on our mailing list.</DD>
+</DL>
+<P>See also this<A href="http://www.tlsecurity.net/unix/ids/sniffer/">
+ index</A> of packet sniffers.</P>
+<P>tcpdump(8) may misbehave if run on the gateways themselves. It is
+ designed to look into a normal IP stack and may become confused if you
+ ask it to display data from a stack which has IPsec in play.</P>
+<P>At one point, the problem was quite severe. Recent versions of
+ tcpdump, however, understand IPsec well enough to be usable on a
+ gateway. You can get the latest version from<A href="http://www.tcpdump.org/">
+ tcpdump.org</A>.</P>
+<P>Even with a recent tcpdump, some care is required. Here is part of a
+ post from Henry on the topic:</P>
+<PRE>&gt; a) data from sunset to sunrise or the other way is not being
+&gt; encrypted (I am using tcpdump (ver. 3.4) -x/ping -p to check
+&gt; packages) 
+
+What *interface* is tcpdump being applied to?  Use the -i option to
+control this.  It matters!  If tcpdump is looking at the ipsecN
+interfaces, e.g. ipsec0, then it is seeing the packets before they are
+encrypted or after they are decrypted, so of course they don't look
+encrypted.  You want to have tcpdump looking at the actual hardware
+interfaces, e.g. eth0. 
+
+Actually, the only way to be *sure* what you are sending on the wire is to
+have a separate machine eavesdropping on the traffic.  Nothing you can do
+on the machines actually running IPsec is 100% guaranteed reliable in this
+area (although tcpdump is a lot better now than it used to be).</PRE>
+<P>The most certain way to examine IPsec packets is to look at them on
+ the wire. For security, you need to be certain, so we recommend doing
+ that. To do so, you need a<STRONG> separate sniffer machine located
+ between the two gateways</STRONG>. This machine can be routing IPsec
+ packets, but it must not be an IPsec gateway. Network configuration for
+ such testing is discussed<A href="#testnet"> above</A>.</P>
+<P>Here's another mailing list message with advice on using tcpdump(8):</P>
+<PRE>Subject: RE: [Users] Encrypted???
+   Date: Thu, 29 Nov 2001
+   From: &quot;Joe Patterson&quot; &lt;jpatterson@asgardgroup.com&gt;
+
+tcpdump -nl -i $EXT-IF proto 50
+
+-nl tells it not to buffer output or resolve names (if you don't do that it
+may confuse you by not outputing anything for a while), -i $EXT-IF (replace
+with your external interface) tells it what interface to listen on, and
+proto 50 is ESP.  Use &quot;proto 51&quot; if for some odd reason you're using AH, and
+&quot;udp port 500&quot; if you want to see the isakmp key exchange/tunnel setup
+packets.
+
+You can also run `tcpdump -nl -i ipsec0` to see what traffic is on that
+virtual interface.  Anything you see there *should* be either encrypted or
+dropped (unless you've turned on some strange options in your ipsec.conf
+file)
+
+Another very handy thing is ethereal (http://www.ethereal.com/) which runs
+on just about anything, has a nice gui interface (or a nice text-based
+interface), and does a great job of protocol  breakdown.  For ESP and AH
+it'll basically just tell you that there's a packet of that protocol, and
+what the spi is, but for isakmp it'll actually show you a lot of the tunnel
+setup information (until it gets to the point in the protocol where isakmp
+is encrypted....)</PRE>
+<H2><A name="verify.crypt">Verifying encryption</A></H2>
+<P>The question of how to verify that messages are actually encrypted
+ has been extensively discussed on the mailing list. See this<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/07/msg00262.html">
+ thread</A>.</P>
+<P>If you just want to verify that packets are encrypted, look at them
+ with a packet sniffer (see<A href="#tcpdump.test"> previous section</A>
+) located between the gateways. The packets should, except for some of
+ the header information, be utterly unintelligible.<STRONG> The output
+ of good encryption looks<EM> exactly</EM> like random noise</STRONG>.</P>
+<P>A packet sniffer can only tell you that the data you looked at was
+ encrypted. If you have stronger requirements -- for example if your
+ security policy requires verification that plaintext is not leaked
+ during startup or under various anomolous conditions -- then you will
+ need to devise much more thorough tests. If you do that, please post
+ any results or methodological details which your security policy allows
+ you to make public.</P>
+<P>You can put recognizable data into ping packets with something like:</P>
+<PRE>        ping -p feedfacedeadbeef 11.0.1.1</PRE>
+<P>&quot;feedfacedeadbeef&quot; is a legal hexadecimal pattern that is easy to
+ pick out of hex dumps.</P>
+<P>For other protocols, you may need to check if you have encrypted data
+ or ASCII text. Encrypted data has approximately equal frequencies for
+ all 256 possible characters. ASCII text has most characters in the
+ printable range 0x20-0x7f, a few control characters less than 0x20, and
+ none at all in the range 0x80-0xff. 0x20, space, is a good character to
+ look for. In normal English text space occurs about once in seven
+ characters, versus about once in 256 for random or encrypted data.</P>
+<P>One thing to watch for: the output of good compression, like that of
+ good encryption, looks just like random noise. You cannot tell just by
+ looking at a data stream whether it has been compressed, encrypted, or
+ both. You need a little care not to mistake compressed data for
+ encrypted data in your testing.</P>
+<P>Note also that weak encryption also produces random-looking output.
+ You cannot tell whether the encryption is strong by looking at the
+ output. To be sure of that, you would need to have both the algorithms
+ and the implementation examined by experts.</P>
+<P>For IPsec, you can get partial assurance from interoperability tests.
+ See our<A href="interop.html"> interop</A> document. When twenty
+ products all claim to implement<A href="#3DES"> 3DES</A>, and they all
+ talk to each other, you can be fairly sure they have it right. Of
+ course, you might wonder whether all the implementers are consipring to
+ trick you or, more plausibly, whether some implementations might have
+ &quot;back doors&quot; so they can get also it wrong when required.. If you're
+ seriously worried about things like that, you need to get the code you
+ use audited (good luck if it is not Open Source), or perhaps to talk to
+ a psychiatrist about treatments for paranoia.</P>
+<H2><A name="mail.test">Mailing list pointers</A></H2>
+<P>Additional information on testing can be found in these<A href="mail.html">
+ mailing list</A> messages:</P>
+<UL>
+<LI>a user's detailed<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/11/msg00571.html">
+ setup diary</A> for his testbed network</LI>
+<LI>a FreeS/WAN team member's<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/11/msg00425.html">
+ notes</A> from testing at an IPsec interop &quot;bakeoff&quot;</LI>
+</UL>
+<HR>
+<H1><A name="kernelconfig">Kernel configuration for FreeS/WAN</A></H1>
+<P> This section lists many of the options available when configuring a
+ Linux kernel, and explains how they should be set on a FreeS/WAN IPsec
+ gateway.</P>
+<H2><A name="notall">Not everyone needs to worry about kernel
+ configuration</A></H2>
+<P>Note that in many cases you do not need to mess with these.</P>
+<P> You may have a Linux distribution which comes with FreeS/WAN
+ installed (see this<A href="#products"> list</A>). In that case, you
+ need not do a FreeS/WAN installation or a kernel configuration. Of
+ course, you might still want to configure and rebuild your kernel to
+ improve performance or security. This can be done with standard tools
+ described in the<A href="http://www.linuxdoc.org/HOWTO/Kernel-HOWTO.html">
+ Kernel HowTo</A>.</P>
+<P>If you need to install FreeS/WAN, then you do need to configure a
+ kernel. However, you may choose to do that using the simplest
+ procedure:</P>
+<UL>
+<LI>Configure, build and test a kernel for your system before adding
+ FreeS/WAN. See the<A href="http://www.linuxdoc.org/HOWTO/Kernel-HOWTO.html">
+ Kernel HowTo</A> for details.<STRONG> This step cannot be skipped</STRONG>
+. FreeS/WAN needs the results of your configuration.</LI>
+<LI>Then use FreeS/WAN's<VAR> make oldgo</VAR> command. This sets
+ everything FreeS/WAN needs and retains your values everywhere else.</LI>
+</UL>
+<P> This document is for those who choose to configure their FreeS/WAN
+ kernel themselves.</P>
+<H2><A name="assume">Assumptions and notation</A></H2>
+<P> Help text for most kernel options is included with the kernel files,
+ and is accessible from within the configuration utilities. We assume
+ you will refer to that, and to the<A href="http://www.linuxdoc.org/HOWTO/Kernel-HOWTO.html">
+ Kernel HowTo</A>, as necessary. This document covers only the
+ FreeS/WAN-specific aspects of the problem.</P>
+<P> To avoid duplication, this document section does not cover settings
+ for the additional IPsec-related kernel options which become available
+ after you have patched your kernel with FreeS/WAN patches. There is
+ help text for those available from within the configuration utility.</P>
+<P> We assume a common configuration in which the FreeS/WAN IPsec
+ gateway is also doing ipchains(8) firewalling for a local network, and
+ possibly masquerading as well.</P>
+<P> Some suggestions below are labelled as appropriate for &quot;a true
+ paranoid&quot;. By this we mean they may cause inconvenience and it is not
+ entirely clear they are necessary, but they appear to be the safest
+ choice. Not using them might entail some risk. Of course one suggested
+ mantra for security administrators is: &quot;I know I'm paranoid. I wonder
+ if I'm paranoid enough.&quot;</P>
+<H3><A name="labels">Labels used</A></H3>
+<P> Six labels are used to indicate how options should be set. We mark
+ the labels with [square brackets]. For two of these labels, you have no
+ choice:</P>
+<DL>
+<DT>[required]</DT>
+<DD>essential for FreeS/WAN operation.</DD>
+<DT>[incompatible]</DT>
+<DD>incompatible with FreeS/WAN.</DD>
+</DL>
+<P>those must be set correctly or FreeS/WAN will not work</P>
+<P>FreeS/WAN should work with any settings of the others, though of
+ course not all combinations have been tested. We do label these in
+ various ways, but<EM> these labels are only suggestions</EM>.</P>
+<DL>
+<DT>[recommended]</DT>
+<DD>useful on most FreeS/WAN gateways</DD>
+<DT>[disable]</DT>
+<DD>an unwelcome complication on a FreeS/WAN gateway.</DD>
+<DT>[optional]</DT>
+<DD>Your choice. We outline issues you might consider.</DD>
+<DT>[anything]</DT>
+<DD>This option has no direct effect on FreeS/WAN and related tools, so
+ you should be able to set it as you please.</DD>
+</DL>
+<P> Of course complexity is an enemy in any effort to build secure
+ systems.<STRONG> For maximum security, any feature that can reasonably
+ be turned off should be</STRONG>. &quot;If in doubt, leave it out.&quot;</P>
+<H2><A name="kernelopt">Kernel options for FreeS/WAN</A></H2>
+<P> Indentation is based on the nesting shown by 'make menuconfig' with
+ a 2.2.16 kernel for the i386 architecture.</P>
+<DL>
+<DT><A name="maturity">Code maturity and level options</A></DT>
+<DD>
+<DL>
+<DT><A name="devel">Prompt for development ... code/drivers</A></DT>
+<DD>[optional] If this is<VAR> no</VAR>, experimental drivers are not
+ shown in later menus.
+<P>For most FreeS/WAN work,<VAR> no</VAR> is the preferred setting.
+ Using new or untested components is too risky for a security gateway.</P>
+<P>However, for some hardware (such as the author's network cards) the
+ only drivers available are marked<VAR> new/experimental</VAR>. In such
+ cases, you must enable this option or your cards will not appear under
+ &quot;network device support&quot;. A true paranoid would leave this option off
+ and replace the cards.</P>
+</DD>
+<DT>Processor type and features</DT>
+<DD>[anything]</DD>
+<DT>Loadable module support</DT>
+<DD>
+<DL>
+<DT>Enable loadable module support</DT>
+<DD>[optional] A true paranoid would disable this. An attacker who has
+ root access to your machine can fairly easily install a bogus module
+ that does awful things, provided modules are enabled. A common tool for
+ attackers is a &quot;rootkit&quot;, a set of tools the attacker uses once he or
+ she has become root on your system. The kit introduces assorted
+ additional compromises so that the attacker will continue to &quot;own&quot; your
+ system despite most things you might do to recovery the situation. For
+ Linux, there is a tool called<A href="http://www.sans.org/newlook/resources/IDFAQ/knark.htm">
+ knark</A> which is basically a rootkit packaged as a kernel module.
+<P>With modules disabled, an attacker cannot install a bogus module. The
+ only way he can achieve the same effects is to install a new kernel and
+ reboot. This is considerably more likely to be noticed.</P>
+<P>Many FreeS/WAN gateways run with modules enabled. This simplifies
+ some administrative tasks and some ipchains features are available only
+ as modules. Once an enemy has root on your machine your security is
+ nil, so arguably defenses which come into play only in that situation
+ are pointless.</P>
+<P></P>
+</DD>
+<DT>Set version information ....</DT>
+<DD>[optional] This provides a check to prevent loading modules compiled
+ for a different kernel.</DD>
+<DT>Kernel module loader</DT>
+<DD>[disable] It gives little benefit on a typical FreeS/WAN gate and
+ entails some risk.</DD>
+</DL>
+</DD>
+<DT>General setup</DT>
+<DD>We list here only the options that matter for FreeS/WAN.
+<DL>
+<DT>Networking support</DT>
+<DD>[required]</DD>
+<DT>Sysctl interface</DT>
+<DD>[optional] If this option is turned on and the<VAR> /proc</VAR>
+ filesystem installed, then you can control various system behaviours by
+ writing to files under<VAR> /proc/sys</VAR>. For example:
+<PRE>        echo 1 &gt; /proc/sys/net/ipv4/ipforward</PRE>
+ turns IP forwarding on.
+<P>Disabling this option breaks many firewall scripts. A true paranoid
+ would disable it anyway since it might conceivably be of use to an
+ attacker.</P>
+</DD>
+</DL>
+</DD>
+<DT>Plug and Play support</DT>
+<DD>[anything]</DD>
+<DT>Block devices</DT>
+<DD>[anything]</DD>
+<DT>Networking options</DT>
+<DD>
+<DL>
+<DT>Packet socket</DT>
+<DD>[optional] This kernel feature supports tools such as tcpdump(8)
+ which communicate directly with network hardware, bypassing kernel
+ protocols. This is very much a two-edged sword:
+<UL>
+<LI>such tools can be very useful to the firewall admin, especially
+ during initial testing</LI>
+<LI>should an evildoer breach your firewall, such tools could give him
+ or her a great deal of information about the rest of your network</LI>
+</UL>
+ We recommend disabling this option on production gateways.</DD>
+<DT><A name="netlink">Kernel/User netlink socket</A></DT>
+<DD>[optional] Required if you want to use<A href="#adv"> advanced
+ router</A> features.</DD>
+<DT>Routing messages</DT>
+<DD>[optional]</DD>
+<DT>Netlink device emulation</DT>
+<DD>[optional]</DD>
+<DT>Network firewalls</DT>
+<DD>[recommended] You need this if the IPsec gateway also functions as a
+ firewall.
+<P>Even if the IPsec gateway is not your primary firewall, we suggest
+ setting this so that you can protect the gateway with at least basic
+ local packet filters.</P>
+</DD>
+<DT>Socket filtering</DT>
+<DD>[disable] This enables an older filtering interface. We suggest
+ using ipchains(8) instead. To do that, set the &quot;Network firewalls&quot;
+ option just above, and not this one.</DD>
+<DT>Unix domain sockets</DT>
+<DD>[required] These sockets are used for communication between the<A href="manpage.d/ipsec.8.html">
+ ipsec(8)</A> commands and the<A href="manpage.d/ipsec_pluto.8.html">
+ ipsec_pluto(8)</A> daemon.</DD>
+<DT>TCP/IP networking</DT>
+<DD>[required]
+<DL>
+<DT>IP: multicasting</DT>
+<DD>[anything]</DD>
+<DT><A name="adv">IP: advanced router</A></DT>
+<DD>[optional] This gives you policy routing, which some people have
+ used to good advantage in their scripts for FreeS/WAN gateway
+ management. It is not used in our distributed scripts, so not required
+ unless you want it for custom scripts. It requires the<A href="#netlink">
+ netlink</A> interface between kernel code and the iproute2(8) command.</DD>
+<DT>IP: kernel level autoconfiguration</DT>
+<DD>[disable] It gives little benefit on a typical FreeS/WAN gate and
+ entails some risk.</DD>
+<DT>IP: firewall packet netlink device</DT>
+<DD>[disable]</DD>
+<DT>IP: transparent proxy support</DT>
+<DD>[optional] This is required in some firewall configurations, but
+ should be disabled unless you have a definite need for it.</DD>
+<DT>IP: masquerading</DT>
+<DD>[optional] Required if you want to use<A href="#non-routable">
+ non-routable</A> private IP addresses for your local network.</DD>
+<DT>IP: Optimize as router not host</DT>
+<DD>[recommended]</DD>
+<DT>IP: tunneling</DT>
+<DD>[required]</DD>
+<DT>IP: GRE tunnels over IP</DT>
+<DD>[anything]</DD>
+<DT>IP: aliasing support</DT>
+<DD>[anything]</DD>
+<DT>IP: ARP daemon support (EXPERIMENTAL)</DT>
+<DD>Not required on most systems, but might prove useful on
+ heavily-loaded gateways.</DD>
+<DT>IP: TCP syncookie support</DT>
+<DD>[recommended] It provides a defense against a<A href="#DOS"> denial
+ of service attack</A> which uses bogus TCP connection requests to waste
+ resources on the victim machine.</DD>
+<DT>IP: Reverse ARP</DT>
+<DD></DD>
+<DT>IP: large window support</DT>
+<DD>[recommended] unless you have less than 16 meg RAM</DD>
+</DL>
+</DD>
+<DT>IPv6</DT>
+<DD>[optional] FreeS/WAN does not currently support IPv6, though work on
+ integrating FreeS/WAN with the Linux IPv6 stack has begun.<A href="#ipv6">
+ Details</A>.
+<P> It should be possible to use IPv4 FreeS/WAN on a machine which also
+ does IPv6. This combination is not yet well tested. We would be quite
+ interested in hearing results from anyone expermenting with it, via the<A
+href="mail.html"> mailing list</A>.</P>
+<P> We do not recommend using IPv6 on production FreeS/WAN gateways
+ until more testing has been done.</P>
+</DD>
+<DT>Novell IPX</DT>
+<DD>[disable]</DD>
+<DT>Appletalk</DT>
+<DD>[disable] Quite a few Linux installations use IP but also have some
+ other protocol, such as Appletalk or IPX, for communication with local
+ desktop machines. In theory it should be possible to configure IPsec
+ for the IP side of things without interfering with the second protocol.
+<P>We do not recommend this. Keep the software on your gateway as simple
+ as possible. If you need a Linux-based Appletalk or IPX server, use a
+ separate machine.</P>
+</DD>
+</DL>
+</DD>
+<DT>Telephony support</DT>
+<DD>[anything]</DD>
+<DT>SCSI support</DT>
+<DD>[anything]</DD>
+<DT>I2O device support</DT>
+<DD>[anything]</DD>
+<DT>Network device support</DT>
+<DD>[anything] should work, but there are some points to note.
+<P>The development team test almost entirely on 10 or 100 megabit
+ Ethernet and modems. In principle, any device that can do IP should be
+ just fine for IPsec, but in the real world any device that has not been
+ well-tested is somewhat risky. By all means try it, but don't bet your
+ project on it until you have solid test results.</P>
+<P>If you disabled experimental drivers in the<A href="#maturity"> Code
+ maturity</A> section above, then those drivers will not be shown here.
+ Check that option before going off to hunt for missing drivers.</P>
+<P>If you want Linux to automatically find more than one ethernet
+ interface at boot time, you need to:</P>
+<UL>
+<LI>compile the appropriate driver(s) into your kernel. Modules will not
+ work for this</LI>
+<LI>add a line such as
+<PRE>
+   append=&quot;ether=0,0,eth0 ether=0,0,eth1&quot;
+</PRE>
+ to your /etc/lilo.conf file. In some cases you may need to specify
+ parameters such as IRQ or base address. The example uses &quot;0,0&quot; for
+ these, which tells the system to search. If the search does not succeed
+ on your hardware, then you should retry with explicit parameters. See
+ the lilo.conf(5) man page for details.</LI>
+<LI>run lilo(8)</LI>
+</UL>
+ Having Linux find the cards this way is not necessary, but is usually
+ more convenient than loading modules in your boot scripts.</DD>
+<DT>Amateur radio support</DT>
+<DD>[anything]</DD>
+<DT>IrDA (infrared) support</DT>
+<DD>[anything]</DD>
+<DT>ISDN subsystem</DT>
+<DD>[anything]</DD>
+<DT>Old CDROM drivers</DT>
+<DD>[anything]</DD>
+<DT>Character devices</DT>
+<DD>The only required character device is:
+<DL>
+<DT>random(4)</DT>
+<DD>[required] This is a source of<A href="#random"> random</A> numbers
+ which are required for many cryptographic protocols, including several
+ used in IPsec.
+<P>If you are comfortable with C source code, it is likely a good idea
+ to go in and adjust the<VAR> #define</VAR> lines in<VAR>
+ /usr/src/linux/drivers/char/random.c</VAR> to ensure that all sources
+ of randomness are enabled. Relying solely on keyboard and mouse
+ randomness is dubious procedure for a gateway machine. You could also
+ increase the randomness pool size from the default 512 bytes (128
+ 32-bit words).</P>
+</DD>
+</DL>
+</DD>
+<DT>Filesystems</DT>
+<DD>[anything] should work, but we suggest limiting a gateway machine to
+ the standard Linux ext2 filesystem in most cases.</DD>
+<DT>Network filesystems</DT>
+<DD>[disable] These systems are an unnecessary risk on an IPsec gateway.</DD>
+<DT>Console drivers</DT>
+<DD>[anything]</DD>
+<DT>Sound</DT>
+<DD>[anything] should work, but we suggest enabling sound only if you
+ plan to use audible alarms for firewall problems.</DD>
+<DT>Kernel hacking</DT>
+<DD>[disable] This might be enabled on test machines, but should not be
+ on production gateways.</DD>
+</DL>
+</DD>
+</DL>
+<HR>
+<H1><A name="adv_config">Other configuration possibilities</A></H1>
+<P>This document describes various options for FreeS/WAN configuration
+ which are less used or more complex (often both) than the standard
+ cases described in our<A href="#config"> config</A> and<A href="#quick_guide">
+ quickstart</A> documents.</P>
+<H2><A name="thumb">Some rules of thumb about configuration</A></H2>
+<H3><A name="cheap.tunnel">Tunnels are cheap</A></H3>
+<P>Nearly all of the overhead in IPsec processing is in the encryption
+ and authentication of packets. Our<A href="performance.html">
+ performance</A> document discusses these overheads.</P>
+<P>Beside those overheads, the cost of managing additional tunnels is
+ trivial. Whether your gateway supports one tunnel or ten just does not
+ matter. A hundred might be a problem; there is a<A href="#biggate">
+ section</A> on this in the performance document.</P>
+<P>So, in nearly all cases, if using multiple tunnels gives you a
+ reasonable way to describe what you need to do, you should describe it
+ that way in your configuration files.</P>
+<P>For example, one user recently asked on a mailing list about this
+ network configuration:</P>
+<PRE>        netA---gwA---gwB---netB
+                            |----netC
+
+   netA and B are secured netC not.
+   netA and gwA can not access netC</PRE>
+<P>The user had constructed only one tunnel, netA to netB, and wanted to
+ know how to use ip-route to get netC packets into it. This is entirely
+ unnecessary. One of the replies was:</P>
+<PRE>  The simplest way and indeed the right way to
+  solve this problem is to set up two connections:
+
+        leftsubnet=NetA
+        left=gwA
+        right=gwB
+        rightsubnet=NetB
+  and
+        leftsubnet=NetA
+        left=gwA
+        right=gwB
+        rightsubnet=NetC</PRE>
+<P>This would still be correct even if we added nets D, E, F, ... to the
+ above diagram and needed twenty tunnels.</P>
+<P>Of course another possibility would be to just use one tunnel, with a
+ subnet mask that includes both netB and netC (or B, C, D, ...). See
+ next section.</P>
+<P>In general, you can construct as many tunnels as you need. Networks
+ like netC in this example that do not connect directly to the gateway
+ are fine, as long as the gateway can route to them.</P>
+<P>The number of tunnels can become an issue if it reaches 50 or so.
+ This is discussed in the<A href="#biggate"> performance</A> document.
+ Look there for information on supporting hundreds of Road Warriors from
+ one gateway.</P>
+<P>If you find yourself with too many tunnels for some reason like
+ having eight subnets at one location and nine at another so you end up
+ with 9*8=72 tunnels, read the next section here.</P>
+<H3><A name="subnet.size">Subnet sizes</A></H3>
+<P>The subnets used in<VAR> leftsubnet</VAR> and<VAR> rightsubnet</VAR>
+ can be of any size that fits your needs, and they need not correspond
+ to physical networks.</P>
+<P>You adjust the size by changing the<A href="#subnet"> subnet mask</A>
+, the number after the slash in the subnet description. For example</P>
+<UL>
+<LI>in 192.168.100.0/24 the /24 mask says 24 bits are used to designate
+ the network. This leave 8 bits to label machines. This subnet has 256
+ addresses. .0 and .255 are reserved, so it can have 254 machines.</LI>
+<LI>A subnet with a /23 mask would be twice as large, 512 addresses.</LI>
+<LI>A subnet with a /25 mask would be half the size, 128 addresses.</LI>
+<LI>/0 is the whole Internet</LI>
+<LI>/32 is a single machine</LI>
+</UL>
+<P>As an example of using these in connection descriptions, suppose your
+ company's head office has four physical networks using the address
+ ranges:</P>
+<DL>
+<DT>192.168.100.0/24</DT>
+<DD>development</DD>
+<DT>192.168.101.0/24</DT>
+<DD>production</DD>
+<DT>192.168.102.0/24</DT>
+<DD>marketing</DD>
+<DT>192.168.103.0/24</DT>
+<DD>administration</DD>
+</DL>
+<P>You can use exactly those subnets in your connection descriptions, or
+ use larger subnets to grant broad access if required:</P>
+<DL>
+<DT>leftsubnet=192.168.100.0/24</DT>
+<DD>remote hosts can access only development</DD>
+<DT>leftsubnet=192.168.100.0/23</DT>
+<DD>remote hosts can access development or production</DD>
+<DT>leftsubnet=192.168.102.0/23</DT>
+<DD>remote hosts can access marketing or administration</DD>
+<DT>leftsubnet=192.168.100.0/22</DT>
+<DD>remote hosts can access any of the four departments</DD>
+</DL>
+<P>or use smaller subnets to restrict access:</P>
+<DL>
+<DT>leftsubnet=192.168.103.0/24</DT>
+<DD>remote hosts can access any machine in administration</DD>
+<DT>leftsubnet=192.168.103.64/28</DT>
+<DD>remote hosts can access only certain machines in administration.</DD>
+<DT>leftsubnet=192.168.103.42/32</DT>
+<DD>remote hosts can access only one particular machine in
+ administration</DD>
+</DL>
+<P>To be exact, 192.68.103.64/28 means all addresses whose top 28 bits
+ match 192.168.103.64. There are 16 of these because there are 16
+ possibilities for the remainingg 4 bits. Their addresses are
+ 192.168.103.64 to 192.168.103.79.</P>
+<P>Each connection description can use a different subnet if required.</P>
+<P>It is possible to use all the examples above on the same FreeS/WAN
+ gateway, each in a different connection description, perhaps for
+ different classes of user or for different remote offices.</P>
+<P>It is also possible to have multiple tunnels using different<VAR>
+ leftsubnet</VAR> descriptions with the same<VAR> right</VAR>. For
+ example, when the marketing manager is on the road he or she might have
+ access to:</P>
+<DL>
+<DT>leftsubnet=192.168.102.0/24</DT>
+<DD>all machines in marketing</DD>
+<DT>192.168.101.32/29</DT>
+<DD>some machines in production</DD>
+<DT>leftsubnet=192.168.103.42/32</DT>
+<DD>one particular machine in administration</DD>
+</DL>
+<P>This takes three tunnels, but tunnels are cheap. If the laptop is set
+ up to build all three tunnels automatically, then he or she can access
+ all these machines concurrently, perhaps from different windows.</P>
+<H3><A name="example.more">Other network layouts</A></H3>
+<P>Here is the usual network picture for a site-to-site VPN::</P>
+<PRE>     Sunset==========West------------------East=========Sunrise
+           local net       untrusted net       local net</PRE>
+<P>and for the Road Warrior::</P>
+<PRE>                                           telecommuter's PC or
+                                           traveller's laptop
+     Sunset==========West------------------East
+         corporate LAN     untrusted net</PRE>
+<P>Other configurations are also possible.</P>
+<H4><A name="internet.subnet">The Internet as a big subnet</A></H4>
+<P>A telecommuter might have:</P>
+<PRE>     Sunset==========West------------------East ================= firewall --- the Internet
+         home network      untrusted net        corporate network</PRE>
+<P>This can be described as a special case of the general
+ subnet-to-subnet connection. The subnet on the right is 0.0.0.0/0, the
+ whole Internet.</P>
+<P>West (the home gateway) can have its firewall rules set up so that
+ only IPsec packets to East are allowed out. It will then behave as if
+ its only connection to the world was a wire to East.</P>
+<P>When machines on the home network need to reach the Internet, they do
+ so via the tunnel, East and the corporate firewall. From the viewpoint
+ of the Internet (perhaps of some EvilDoer trying to break in!), those
+ home office machines are behind the firewall and protected by it.</P>
+<H4><A name="wireless.config">Wireless</A></H4>
+<P>Another possible configuration comes up when you do not trust the
+ local network, either because you have very high security standards or
+ because your are using easily-intercepted wireless signals.</P>
+<P>Some wireless networks have built-in encryption called<A href="#WEP">
+ WEP</A>, but its security is dubious. It is a fairly common practice to
+ use IPsec instead.</P>
+<P>In this case, part of your network may look like this:</P>
+<PRE>          West-----------------------------East == the rest of your network
+     workstation   untrusted wireless net</PRE>
+<P>Of course, there would likely be several wireless workstations, each
+ with its own IPsec tunnel to the East gateway.</P>
+<P>The connection descriptions look much like Road Warrior descriptions:</P>
+<UL>
+<LI>each workstation should have its own unique
+<UL>
+<LI>identifier for IPsec</LI>
+<LI>RSA key</LI>
+<LI>connection description.</LI>
+</UL>
+</LI>
+<LI>on the gateway, use<VAR> left=%any</VAR>, or the workstation IP
+ address</LI>
+<LI>on workstations,<VAR> left=%defaultroute</VAR>, or the workstation
+ IP address</LI>
+<LI><VAR>leftsubnet=</VAR> is not used.</LI>
+</UL>
+<P>The<VAR> rightsubnet=</VAR> parameter might be set in any of several
+ ways:</P>
+<DL>
+<DT>rightsubnet=0.0.0.0/0</DT>
+<DD>allowing workstations to access the entire Internet (see<A href="#internet.subnet">
+ above</A>)</DD>
+<DT>rightsubnet=a.b.c.0/24</DT>
+<DD>allowing access to your entire local network</DD>
+<DT>rightsubnet=a.b.c.d/32</DT>
+<DD>restricting the workstation to connecting to a particular server</DD>
+</DL>
+<P>Of course you can mix and match these as required. For example, a
+ university might allow faculty full Internet access while letting
+ student laptops connect only to a group of lab machines.</P>
+<H2><A name="choose">Choosing connection types</A></H2>
+<P>One choice you need to make before configuring additional connections
+ is what type or types of connections you will use. There are several
+ options, and you can use more than one concurrently.</P>
+<H3><A name="man-auto">Manual vs. automatic keying</A></H3>
+<P>IPsec allows two types of connections, with manual or automatic
+ keying. FreeS/WAN starts them with commands such as:</P>
+<PRE>        ipsec manual --up <VAR>name</VAR>
+        ipsec auto --up <VAR>name</VAR></PRE>
+<P>The difference is in how they are keyed.</P>
+<DL>
+<DT><A href="#manual">Manually keyed</A> connections</DT>
+<DD>use keys stored in<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf</A>
+.</DD>
+<DT><A href="#auto">Automatically keyed</A> connections</DT>
+<DD>use keys automatically generated by the Pluto key negotiation
+ daemon. The key negotiation protocol,<A href="#IKE"> IKE</A>, must
+ authenticate the other system. (It is vulnerable to a<A href="#middle">
+ man-in-the-middle attack</A> if used without authentication.) We
+ currently support two authentication methods:
+<UL>
+<LI>using shared secrets stored in<A href="manpage.d/ipsec.secrets.5.html">
+ ipsec.secrets</A>.</LI>
+<LI>RSA<A href="#public"> public key</A> authentication, with our
+ machine's private key in<A href="manpage.d/ipsec.secrets.5.html">
+ ipsec.secrets</A>. Public keys for other machines may either be placed
+ in<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf</A> or provided via
+ DNS.</LI>
+</UL>
+<P>A third method, using RSA keys embedded in<A href="#X509"> X.509</A>
+ certtificates, is provided by user<A href="#patch"> patches</A>.</P>
+</DD>
+</DL>
+<P><A href="#manual">Manually keyed</A> connections provide weaker
+ security than<A href="#auto"> automatically keyed</A> connections. An
+ opponent who reads ipsec.secrets(5) gets your encryption key and can
+ read all data encrypted by it. If he or she has an archive of old
+ messages, all of them back to your last key change are also readable.</P>
+<P>With automatically-(re)-keyed connections, an opponent who reads
+ ipsec.secrets(5) gets the key used to authenticate your system in IKE
+ -- the shared secret or your private key, depending what authentication
+ mechanism is in use. However, he or she does not automatically gain
+ access to any encryption keys or any data.</P>
+<P>An attacker who has your authentication key can mount a<A href="#middle">
+ man-in-the-middle attack</A> and, if that succeeds, he or she will get
+ encryption keys and data. This is a serious danger, but it is better
+ than having the attacker read everyting as soon as he or she breaks
+ into ipsec.secrets(5).. Moreover, the keys change often so an opponent
+ who gets one key does not get a large amount of data. To read all your
+ data, he or she would have to do a man-in-the-middle attack at every
+ key change.</P>
+<P>We discuss using<A href="#prodman"> manual keying in production</A>
+ below, but this is<STRONG> not recommended</STRONG> except in special
+ circumstances, such as needing to communicate with some implementation
+ that offers no auto-keyed mode compatible with FreeS/WAN.</P>
+<P>Manual keying may also be useful for testing. There is some
+ discussion of this in our<A href="#man4debug"> FAQ</A>.</P>
+<H3><A name="auto-auth">Authentication methods for auto-keying</A></H3>
+<P>The IKE protocol which Pluto uses to negotiate connections between
+ gateways must use some form of authentication of peers. A gateway must
+ know who it is talking to before it can create a secure connection. We
+ support two basic methods for this authentication:</P>
+<UL>
+<LI>shared secrets, stored in<A href="manpage.d/ipsec.secrets.5.html">
+ ipsec.secrets(5)</A></LI>
+<LI>RSA authentication</LI>
+</UL>
+<P>There are, howver, several variations on the RSA theme, using
+ different methods of managing the RSA keys:</P>
+<UL>
+<LI>our RSA private key in<A href="manpage.d/ipsec.secrets.5.html">
+ ipsec.secrets(5)</A> with other gateways' public keys
+<DL>
+<DT>either</DT>
+<DD>stored in<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf(5)</A></DD>
+<DT>or</DT>
+<DD>looked up via<A href="#DNS"> DNS</A></DD>
+</DL>
+</LI>
+<LI>authentication with<A href="#X509"> x.509</A> certificates.; See our<A
+href="#patch"> links section</A> for information on user-contributed
+ patches for this.:</LI>
+</UL>
+<P>Public keys in<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf(5</A>
+) give a reasonably straightforward method of specifying keys for
+ explicitly configured connections.</P>
+<P>Putting public keys in DNS allows us to support<A href="#carpediem">
+ opportunistic encryption</A>. Any two FreeS/WAN gateways can provide
+ secure communication, without either of them having any preset
+ information about the other.</P>
+<P>X.509 certificates may be required to interface to various<A href="#PKI">
+ PKI</A>s.</P>
+<H3><A name="adv-pk">Advantages of public key methods</A></H3>
+<P>Authentication with a<A href="#public"> public key</A> method such as<A
+href="#RSA"> RSA</A> has some important advantages over using shared
+ secrets.</P>
+<UL>
+<LI>no problem of secure transmission of secrets
+<UL>
+<LI>A shared secret must be shared, so you have the problem of
+ transmitting it securely to the other party. If you get this wrong, you
+ have no security.</LI>
+<LI>With a public key technique, you transmit only your public key. The
+ system is designed to ensure that it does not matter if an enemy
+ obtains public keys. The private key never leaves your machine.</LI>
+</UL>
+</LI>
+<LI>easier management
+<UL>
+<LI>Suppose you have 20 branch offices all connecting to one gateway at
+ head office, and all using shared secrets. Then the head office admin
+ has 20 secrets to manage. Each of them must be kept secret not only
+ from outsiders, but also from 19 of the branch office admins. The
+ branch office admins have only one secret each to manage.
+<P>If the branch offices need to talk to each other, this becomes
+ problematic. You need another 20*19/2 = 190 secrets for
+ branch-to-branch communication, each known to exactly two branches. Now
+ all the branch admins have the headache of handling 20 keys, each
+ shared with exactly one other branch or with head office.</P>
+<P>For larger numbers of branches, the number of connections and secrets
+ increases quadratically and managing them becomes a nightmare. A
+ 1000-gateway fully connected network needs 499,500 secrets, each known
+ to exactly two players. There are ways to reduce this problem, for
+ example by introducing a central key server, but these involve
+ additional communication overheads, more administrative work, and new
+ threats that must be carefully guarded against.</P>
+</LI>
+<LI>With public key techniques, the<EM> only</EM> thing you have to keep
+ secret is your private key, and<EM> you keep that secret from everyone</EM>
+.
+<P>As network size increaes, the number of public keys used increases
+ linearly with the number of nodes. This still requires careful
+ administration in large applications, but is nothing like the disaster
+ of a quadratic increase. On a 1000-gateway network, you have 1000
+ private keys, each of which must be kept secure on one machine, and
+ 1000 public keys which must be distributed. This is not a trivial
+ problem, but it is manageable.</P>
+</LI>
+</UL>
+</LI>
+<LI>does not require fixed IP addresses
+<UL>
+<LI>When shared secrets are used in IPsec, the responder must be able to
+ tell which secret to use by looking at the IP address on the incoming
+ packets. When the other parties do not have a fixed IP address to be
+ identified by (for example, on nearly all dialup ISP connections and
+ many cable or ADSL links), this does not work well -- all must share
+ the same secret!</LI>
+<LI>When RSA authentication is in use, the initiator can identify itself
+ by name before the key must be determined. The responder then checks
+ that the message is signed with the public key corresponding to that
+ name.</LI>
+</UL>
+</LI>
+</UL>
+<P>There is also a disadvantage:</P>
+<UL>
+<LI>your private key is a single point of attack, extremely valuable to
+ an enemy
+<UL>
+<LI>with shared secrets, an attacker who steals your ipsec.secrets file
+ can impersonate you or try<A href="#middle"> man-in-the-middle</A>
+ attacks, but can only attack connections described in that file</LI>
+<LI>an attacker who steals your private key gains the chance to attack
+ not only existing connections<EM> but also any future connections</EM>
+ created using that key</LI>
+</UL>
+</LI>
+</UL>
+<P>This is partly counterbalanced by the fact that the key is never
+ transmitted and remains under your control at all times. It is likely
+ necessary, however, to take account of this in setting security policy.
+ For example, you should change gateway keys when an administrator
+ leaves the company, and should change them periodically in any case.</P>
+<P>Overall, public key methods are<STRONG> more secure, more easily
+ managed and more flexible</STRONG>. We recommend that they be used for
+ all connections, unless there is a compelling reason to do otherwise.</P>
+<H2><A name="prodsecrets">Using shared secrets in production</A></H2>
+<P>Generally, public key methods are preferred for reasons given above,
+ but shared secrets can be used with no loss of security, just more work
+ and perhaps more need to take precautions.</P>
+<P>What I call &quot;shared secrets&quot; are sometimes also called &quot;pre-shared
+ keys&quot;. They are used only for for authentication, never for encryption.
+ Calling them &quot;pre-shared keys&quot; has confused some users into thinking
+ they were encryption keys, so I prefer to avoid the term..</P>
+<P>If you are interoperating with another IPsec implementation, you may
+ find its documentation calling them &quot;passphrases&quot;.</P>
+<H3><A name="secrets">Putting secrets in ipsec.secrets(5)</A></H3>
+<P>If shared secrets are to be used to<A href="#authentication">
+ authenticate</A> communication for the<A href="#DH"> Diffie-Hellman</A>
+ key exchange in the<A href="#IKE"> IKE</A> protocol, then those secrets
+ must be stored in<VAR> /etc/ipsec.secrets</VAR>. For details, see the<A href="manpage.d/ipsec.secrets.5.html">
+ ipsec.secrets(5)</A> man page.</P>
+<P>A few considerations are vital:</P>
+<UL>
+<LI>make the secrets long and unguessable. Since they need not be
+ remembered by humans, very long ugly strings may be used. We suggest
+ using our<A href="manpage.d/ipsec_ranbits.8.html"> ipsec_ranbits(8)</A>
+ utility to generate long (128 bits or more) random strings.</LI>
+<LI>transmit secrets securely. You have to share them with other
+ systems, but you lose if they are intercepted and used against you. Use<A
+href="#PGP"> PGP</A>,<A href="#ssh"> SSH</A>, hand delivery of a floppy
+ disk which is then destroyed, or some other trustworthy method to
+ deliver them.</LI>
+<LI>store secrets securely, in root-owned files with permissions
+ rw------.</LI>
+<LI>limit sharing of secrets. Alice, Bob, Carol and Dave may all talk to
+ each other, but only Alice and Bob should know the secret for an
+ Alice-Bob link.</LI>
+<LI><STRONG>do not share private keys</STRONG>. The private key for RSA
+ authentication of your system is stored in<A href="manpage.d/ipsec.secrets.5.html">
+ ipsec.secrets(5)</A>, but it is a different class of secret from the
+ pre-shared keys used for the &quot;shared secret&quot; authentication. No-one but
+ you should have the RSA private key.</LI>
+</UL>
+<P>Each line has the IP addresses of the two gateways plus the secret.
+ It should look something like this:</P>
+<PRE>        10.0.0.1 11.0.0.1 : PSK &quot;jxTR1lnmSjuj33n4W51uW3kTR55luUmSmnlRUuWnkjRj3UuTV4T3USSu23Uk55nWu5TkTUnjT&quot;</PRE>
+<P><VAR>PSK</VAR> indicates the use of a<STRONG> p</STRONG>re-<STRONG>s</STRONG>
+hared<STRONG> k</STRONG>ey. The quotes and the whitespace shown are
+ required.</P>
+<P>You can use any character string as your secret. For security, it
+ should be both long and extremely hard to guess. We provide a utility
+ to generate such strings,<A href="manpage.d/ipsec_ranbits.8.html">
+ ipsec_ranbits(8)</A>.</P>
+<P>You want the same secret on the two gateways used, so you create a
+ line with that secret and the two gateway IP addresses. The
+ installation process supplies an example secret, useful<EM> only</EM>
+ for testing. You must change it for production use.</P>
+<H3><A name="securing.secrets">File security</A></H3>
+<P>You must deliver this file, or the relevant part of it, to the other
+ gateway machine by some<STRONG> secure</STRONG> means.<EM> Don't just
+ FTP or mail the file!</EM> It is vital that the secrets in it remain
+ secret. An attacker who knew those could easily have<EM> all the data
+ on your &quot;secure&quot; connection</EM>.</P>
+<P>This file must be owned by root and should have permissions<VAR>
+ rw-------</VAR>.</P>
+<H3><A name="notroadshared">Shared secrets for road warriors</A></H3>
+<P>You can use a shared secret to support a single road warrior
+ connecting to your gateway, and this is a reasonable thing to do in
+ some circumstances. Public key methods have advantages, discussed<A href="#choose">
+ above</A>, but they are not critical in this case.</P>
+<P>To do this, the line in ipsec.secrets(5) is something like:</P>
+<PRE>        10.0.0.1 0.0.0.0 : PSK &quot;jxTR1lnmSjuj33n4W51uW3kTR55luUmSmnlRUuWnkjRj3UuTV4T3USSu23Uk55nWu5TkTUnjT&quot;</PRE>
+ where the<VAR> 0.0.0.0</VAR> means that any IP address is acceptable.
+<P><STRONG>For more than one road warrior, shared secrets are<EM> not</EM>
+ recommended.</STRONG> If shared secrets are used, then when the
+ responder needs to look up the secret, all it knows about the sender is
+ an IP address. This is fine if the sender is at a fixed IP address
+ specified in the config file. It is also fine if only one road warrior
+ uses the wildcard<VAR> 0.0.0.0</VAR> address. However, if you have more
+ than one road warrior using shared secret authentication, then they
+ must all use that wildcard and therefore<STRONG> all road warriors
+ using PSK autentication must use the same secret</STRONG>. Obviously,
+ this is insecure.</P>
+<P><STRONG>For multiple road warriors, use public key authentication.</STRONG>
+ Each roadwarrior can then have its own identity (our<VAR> leftid=</VAR>
+ or<VAR> rightid=</VAR> parameters), its own public/private key pair,
+ and its own secure connection.</P>
+<H2><A name="prodman">Using manual keying in production</A></H2>
+<P>Generally,<A href="#auto"> automatic keying</A> is preferred over<A href="#manual">
+ manual keying</A> for production use because it is both easier to
+ manage and more secure. Automatic keying frees the admin from much of
+ the burden of managing keys securely, and can provide<A href="#PFS">
+ perfect forward secrecy</A>. This is discussed in more detail<A href="#man-auto">
+ above</A>.</P>
+<P>However, it is possible to use manual keying in production if that is
+ what you want to do. This might be necessary, for example, in order to
+ interoperate with some device that either does not provide automatic
+ keying or provides it in some version we cannot talk to.</P>
+<P>Note that with manual keying<STRONG> all security rests with the keys</STRONG>
+. If an adversary acquires your keys, you've had it. He or she can read
+ everything ever sent with those keys, including old messages he or she
+ may have archived.</P>
+<P>You need to<STRONG> be really paranoid about keys</STRONG> if you're
+ going to rely on manual keying for anything important.</P>
+<UL>
+<LI>keep keys in files with 600 permissions, owned by root</LI>
+<LI>be extremely careful about security of your gateway systems. Anyone
+ who breaks into a gateway and gains root privileges can get all your
+ keys and read everything ever encrypted with those keys, both old
+ messages he has archived and any new ones you may send.</LI>
+<LI>change keys regularly. This can be a considerable bother, (and
+ provides an excellent reason to consider automatic keying instead), but
+ it is<EM> absolutely essential</EM> for security. Consider a manually
+ keyed system in which you leave the same key in place for months:
+<UL>
+<LI>an attacker can have a very large sample of text sent with that key
+ to work with. This makes various cryptographic attacks much more likely
+ to succeed.</LI>
+<LI>The chances of the key being compromised in some non-cryptographic
+ manner -- a spy finds it on a discarded notepad, someone breaks into
+ your server or your building and steals it, a staff member is bribed,
+ tricked, seduced or coerced into revealing it, etc. -- also increase
+ over time.</LI>
+<LI>a successful attacker can read everything ever sent with that key.
+ This makes any successful attack extremely damaging.</LI>
+</UL>
+ It is clear that you must change keys often to have any useful
+ security. The only question is how often.</LI>
+<LI>use<A href="#PGP"> PGP</A> or<A href="#ssh"> SSH</A> for all key
+ transfers</LI>
+<LI>don't edit files with keys in them when someone can look over your
+ shoulder</LI>
+<LI>worry about network security; could someone get keys by snooping
+ packets on the LAN between your X desktop and the gateway?</LI>
+<LI>lock up your backup tapes for the gateway system</LI>
+<LI>... and so on</LI>
+</UL>
+<P>Linux FreeS/WAN provides some facilities to help with this. In
+ particular, it is good policy to<STRONG> keep keys in separate files</STRONG>
+ so you can edit configuration information in /etc/ipsec.conf without
+ exposing keys to &quot;shoulder surfers&quot; or network snoops. We support this
+ with the<VAR> also=</VAR> and<VAR> include</VAR> syntax in<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A>.</P>
+<P>See the last example in our<A href="examples"> examples</A> file. In
+ the /etc/ipsec.conf<VAR> conn samplesep</VAR> section, it has the line:</P>
+<PRE>        also=samplesep-keys</PRE>
+<P>which tells the &quot;ipsec manual&quot; script to insert the configuration
+ description labelled &quot;samplesep-keys&quot; if it can find it. The
+ /etc/ipsec.conf file must also have a line such as:</P>
+<PRE>include ipsec.*.conf</PRE>
+<P>which tells it to read other files. One of those other files then
+ might contain the additional data:</P>
+<PRE>conn samplesep-keys
+  spi=0x200
+  esp=3des-md5-96
+  espenckey=0x01234567_89abcdef_02468ace_13579bdf_12345678_9abcdef0
+  espauthkey=0x12345678_9abcdef0_2468ace0_13579bdf</PRE>
+<P>The first line matches the label in the &quot;also=&quot; line, so the indented
+ lines are inserted. The net effect is exactly as if the inserted lines
+ had occurred in the original file in place of the &quot;also=&quot; line.</P>
+<P>Variables set here are:</P>
+<DL>
+<DT>spi</DT>
+<DD>A number needed by the manual keying code. Any 3-digit hex number
+ will do, but if you have more than one manual connection then<STRONG>
+ spi must be different</STRONG> for each connection.</DD>
+<DT>esp</DT>
+<DD>Options for<A href="#ESP"> ESP</A> (Encapsulated Security Payload),
+ the usual IPsec encryption mode. Settings here are for<A href="#encryption">
+ encryption</A> using<A href="#3DES"> triple DES</A> and<A href="#authentication">
+ authentication</A> using<A href="#MD5"> MD5</A>. Note that encryption
+ without authentication should not be used; it is insecure.</DD>
+<DT>espenkey</DT>
+<DD>Key for ESP encryption. Here, a 192-bit hex number for triple DES.</DD>
+<DT>espauthkey</DT>
+<DD>Key for ESP authentication. Here, a 128-bit hex number for MD5.</DD>
+</DL>
+<P><STRONG>Note</STRONG> that the<STRONG> example keys we supply</STRONG>
+ are intended<STRONG> only for testing</STRONG>. For real use, you
+ should go to automatic keying. If that is not possible, create your own
+ keys for manual mode and keep them secret</P>
+<P>Of course, any files containing keys<STRONG> must</STRONG> have 600
+ permissions and be owned by root.</P>
+<P>If you connect in this way to multiple sites, we recommend that you
+ keep keys for each site in a separate file and adopt some naming
+ convention that lets you pick them all up with a single &quot;include&quot; line.
+ This minimizes the risk of losing several keys to one error or attack
+ and of accidentally giving another site admin keys which he or she has
+ no business knowing.</P>
+<P>Also note that if you have multiple manually keyed connections on a
+ single machine, then the<VAR> spi</VAR> parameter must be different for
+ each one. Any 3-digit hex number is OK, provided they are different for
+ each connection. We reserve the range 0x100 to 0xfff for manual
+ connections. Pluto assigns SPIs from 0x1000 up for automatically keyed
+ connections.</P>
+<P>If<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf(5)</A> contains
+ keys for manual mode connections, then it too must have permissions<VAR>
+ rw-------</VAR>. We recommend instead that, if you must manual keying
+ in production, you keep the keys in separate files.</P>
+<P>Note also that<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf</A>
+ is installed with permissions<VAR> rw-r--r--</VAR>. If you plan to use
+ manually keyed connections for anything more than initial testing, you<B>
+ must</B>:</P>
+<UL>
+<LI>either change permissions to<VAR> rw-------</VAR></LI>
+<LI>or store keys separately in secure files and access them via include
+ statements in<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf</A>.</LI>
+</UL>
+<P>We recommend the latter method for all but the simplest
+ configurations.</P>
+<H3><A name="ranbits">Creating keys with ranbits</A></H3>
+<P>You can create new<A href="#random"> random</A> keys with the<A href="manpage.d/ipsec_ranbits.8.html">
+ ranbits(8)</A> utility. For example, the commands:</P>
+<PRE>      umask 177
+      ipsec ranbits 192  &gt; temp
+      ipsec ranbits 128 &gt;&gt; temp</PRE>
+<P>create keys in the sizes needed for our default algorithms:</P>
+<UL>
+<LI>192-bit key for<A href="#3DES"> 3DES</A> encryption
+<BR> (only 168 bits are used; parity bits are ignored)</LI>
+<LI>128-bit key for keyed<A href="#MD5"> MD5</A> authentication</LI>
+</UL>
+<P>If you want to use<A href="#SHA"> SHA</A> instead of<A href="#MD5">
+ MD5</A>, that requires a 160-bit key</P>
+<P>Note that any<STRONG> temporary files</STRONG> used must be kept<STRONG>
+ secure</STRONG> since they contain keys. That is the reason for the
+ umask command above. The temporary file should be deleted as soon as
+ you are done with it. You may also want to change the umask back to its
+ default value after you are finished working on keys.</P>
+<P>The ranbits utility may pause for a few seconds if not enough entropy
+ is available immediately. See ipsec_ranbits(8) and random(4) for
+ details. You may wish to provide some activity to feed entropy into the
+ system. For example, you might move the mouse around, type random
+ characters, or do<VAR> du /usr &gt; /dev/null</VAR> in the background.</P>
+<H2><A name="boot">Setting up connections at boot time</A></H2>
+<P>You can tell the system to set up connections automatically at boot
+ time by putting suitable stuff in /etc/ipsec.conf on both systems. The
+ relevant section of the file is labelled by a line reading<VAR> config
+ setup</VAR>.</P>
+<P>Details can be found in the<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A> man page. We also provide a file of<A href="examples">
+ example configurations</A>.</P>
+<P>The most likely options are something like:</P>
+<DL>
+<DT>interfaces=&quot;ipsec0=eth0 ipsec1=ppp0&quot;</DT>
+<DD>Tells KLIPS which interfaces to use. Up to four interfaces numbered
+ ipsec[0-3] are supported. Each interface can support an arbitrary
+ number of tunnels.
+<P>Note that for PPP, you give the ppp[0-9] device name here, not the
+ underlying device such as modem (or eth1 if you are using PPPoE).</P>
+</DD>
+<DT>interfaces=%defaultroute</DT>
+<DD>Alternative setting, useful in simple cases. KLIPS will pick up both
+ its interface and the next hop information from the settings of the
+ Linux default route.</DD>
+<DT>forwardcontrol=no</DT>
+<DD>Normally &quot;no&quot;. Set to &quot;yes&quot; if the IP forwarding option is disabled
+ in your network configuration. (This can be set as a kernel
+ configuration option or later. e.g. on Redhat, it's in
+ /etc/sysconfig/network and on SuSE you can adjust it with Yast.) Linux
+ FreeS/WAN will then enable forwarding when starting up and turn it off
+ when going down. This is used to ensure that no packets will be
+ forwarded before IPsec comes up and takes control.</DD>
+<DT>syslog=daemon.error</DT>
+<DD>Used in messages to the system logging daemon (syslogd) to specify
+ what type of software is sending the messages. If the settings are
+ &quot;daemon.error&quot; as in our example, then syslogd treats the messages as
+ error messages from a daemon.
+<P>Note that<A href="#Pluto"> Pluto</A> does not currently pay attention
+ to this variable. The variable controls setup messages only.</P>
+</DD>
+<DT>klipsdebug=</DT>
+<DD>Debug settings for<A href="#KLIPS"> KLIPS</A>.</DD>
+<DT>plutodebug=</DT>
+<DD>Debug settings for<A href="#Pluto"> Pluto</A>.</DD>
+<DT>... for both the above DEBUG settings</DT>
+<DD>Normally, leave empty as shown above for no debugging output.
+<BR> Use &quot;all&quot; for maximum information.
+<BR> See ipsec_klipsdebug(8) and ipsec_pluto(8) man page for other
+ options. Beware that if you set /etc/ipsec.conf to enable debug output,
+ your system's log files may get large quickly.</DD>
+<DT>dumpdir=/safe/directory</DT>
+<DD>Normally, programs started by ipsec setup don't crash. If they do,
+ by default, no core dump will be produced because such dumps would
+ contain secrets. If you find you need to debug such crashes, you can
+ set dumpdir to the name of a directory in which to collect the core
+ file.</DD>
+<DT>manualstart=</DT>
+<DD>List of manually keyed connections to be automatically started at
+ boot time. Useful for testing, but not for long term use. Connections
+ which are automatically started should also be automatically re-keyed.</DD>
+<DT>pluto=yes</DT>
+<DD>Whether to start<A href="#Pluto"> Pluto</A> when ipsec startup is
+ done.
+<BR> This parameter is optional and defaults to &quot;yes&quot; if not present.
+<P>&quot;yes&quot; is strongly recommended for production use so that the keying
+ daemon (Pluto) will automatically re-key the connections regularly. The
+ ipsec-auto parameters ikelifetime, ipseclifetime and reykeywindow give
+ you control over frequency of rekeying.</P>
+</DD>
+<DT>plutoload=&quot;reno-van reno-adam reno-nyc&quot;</DT>
+<DD>List of tunnels (by name, e.g. fred-susan or reno-van in our
+ examples) to be loaded into Pluto's internal database at startup. In
+ this example, Pluto loads three tunnels into its database when it is
+ started.
+<P>If plutoload is &quot;%search&quot;, Pluto will load any connections whose
+ description includes &quot;auto=add&quot; or &quot;auto=start&quot;.</P>
+</DD>
+<DT>plutostart=&quot;reno-van reno-adam reno-nyc&quot;</DT>
+<DD>List of tunnels to attempt to negotiate when Pluto is started.
+<P>If plutostart is &quot;%search&quot;, Pluto will start any connections whose
+ description includes &quot;auto=start&quot;.</P>
+<P>Note that, for a connection intended to be permanent,<STRONG> both
+ gateways should be set try to start</STRONG> the tunnel. This allows
+ quick recovery if either gateway is rebooted or has its IPsec
+ restarted. If only one gateway is set to start the tunnel and the other
+ gateway restarts, the tunnel may not be rebuilt.</P>
+</DD>
+<DT>plutowait=no</DT>
+<DD>Controls whether Pluto waits for one tunnel to be established before
+ starting to negotiate the next. You might set this to &quot;yes&quot;
+<UL>
+<LI>if your gateway is a very limited machine and you need to conserve
+ resources.</LI>
+<LI>for debugging; the logs are clearer if only one connection is
+ brought up at a time</LI>
+</UL>
+ For a busy and resource-laden production gateway, you likely want &quot;no&quot;
+ so that connections are brought up in parallel and the whole process
+ takes less time.</DD>
+</DL>
+<P>The example assumes you are at the Reno office and will use IPsec to
+ Vancouver, New York City and Amsterdam.</P>
+<H2><A name="multitunnel">Multiple tunnels between the same two gateways</A>
+</H2>
+<P>Consider a pair of subnets, each with a security gateway, connected
+ via the Internet:</P>
+<PRE>         192.168.100.0/24           left subnet
+              |
+         192.168.100.1
+         North Gateway
+         101.101.101.101            left
+              |
+         101.101.101.1              left next hop
+         [Internet]
+         202.202.202.1              right next hop
+              |
+         202.202.202.202            right
+         South gateway
+         192.168.200.1
+              |
+         192.168.200.0/24           right subnet</PRE>
+<P>A tunnel specification such as:</P>
+<PRE>conn northnet-southnet
+      left=101.101.101.101
+      leftnexthop=101.101.101.1
+      leftsubnet=192.168.100.0/24
+      leftfirewall=yes
+      right=202.202.202.202
+      rightnexthop=202.202.202.1
+      rightsubnet=192.168.200.0/24
+      rightfirewall=yes</PRE>
+ will allow machines on the two subnets to talk to each other. You might
+ test this by pinging from polarbear (192.168.100.7) to penguin
+ (192.168.200.5).
+<P>However,<STRONG> this does not cover other traffic you might want to
+ secure</STRONG>. To handle all the possibilities, you might also want
+ these connection descriptions:</P>
+<PRE>conn northgate-southnet
+      left=101.101.101.101
+      leftnexthop=101.101.101.1
+      right=202.202.202.202
+      rightnexthop=202.202.202.1
+      rightsubnet=192.168.200.0/24
+      rightfirewall=yes
+
+conn northnet-southgate
+      left=101.101.101.101
+      leftnexthop=101.101.101.1
+      leftsubnet=192.168.100.0/24
+      leftfirewall=yes
+      right=202.202.202.202
+      rightnexthop=202.202.202.1</PRE>
+<P>Without these, neither gateway can do IPsec to the remote subnet.
+ There is no IPsec tunnel or eroute set up for the traffic.</P>
+<P>In our example, with the non-routable 192.168.* addresses used,
+ packets would simply be discarded. In a different configuration, with
+ routable addresses for the remote subnet,<STRONG> they would be sent
+ unencrypted</STRONG> since there would be no IPsec eroute and there
+ would be a normal IP route.</P>
+<P>You might also want:</P>
+<PRE>conn northgate-southgate
+      left=101.101.101.101
+      leftnexthop=101.101.101.1
+      right=202.202.202.202
+      rightnexthop=202.202.202.1</PRE>
+<P>This is required if you want the two gateways to speak IPsec to each
+ other.</P>
+<P>This requires a lot of duplication of details. Judicious use of<VAR>
+ also=</VAR> and<VAR> include</VAR> can reduce this problem.</P>
+<P>Note that, while FreeS/WAN supports all four tunnel types, not all
+ implementations do. In particular, some versions of Windows 2000 and
+ the freely downloadable version of PGP provide only &quot;client&quot;
+ functionality. You cannot use them as gateways with a subnet behind
+ them. To get that functionality, you must upgrade to Windows 2000
+ server or the commercially available PGP products.</P>
+<H3><A name="advroute">One tunnel plus advanced routing</A></H3>
+ It is also possible to use the new routing features in 2.2 and later
+ kernels to avoid most needs for multple tunnels. Here is one mailing
+ list message on the topic:
+<PRE>Subject: Re: linux-ipsec: IPSec packets not entering tunnel?
+   Date: Mon, 20 Nov 2000
+   From: Justin Guyett &lt;jfg@sonicity.com&gt;
+
+On Mon, 20 Nov 2000, Claudia Schmeing wrote:
+
+&gt; Right                                                         Left
+&gt;                      &quot;home&quot;                &quot;office&quot;
+&gt; 10.92.10.0/24 ---- 24.93.85.110 ========= 216.175.164.91 ---- 10.91.10.24/24
+&gt;
+&gt; I've created all four tunnels, and can ping to test each of them,
+&gt; *except* homegate-officenet.
+
+I keep wondering why people create all four tunnels.  Why not route
+traffic generated from home to 10.91.10.24/24 out ipsec0 with iproute2?
+And 99% of the time you don't need to access &quot;office&quot; directly, which
+means you can eliminate all but the subnet&lt;-&gt;subnet connection.</PRE>
+ and FreeS/WAN technical lead Henry Spencer's comment:
+<PRE>&gt; I keep wondering why people create all four tunnels.  Why not route
+&gt; traffic generated from home to 10.91.10.24/24 out ipsec0 with iproute2?
+
+This is feasible, given some iproute2 attention to source addresses, but
+it isn't something we've documented yet... (partly because we're still
+making some attempt to support 2.0.xx kernels, which can't do this, but
+mostly because we haven't caught up with it yet).
+
+&gt; And 99% of the time you don't need to access &quot;office&quot; directly, which
+&gt; means you can eliminate all but the subnet&lt;-&gt;subnet connection.
+
+Correct in principle, but people will keep trying to ping to or from the
+gateways during testing, and sometimes they want to run services on the
+gateway machines too.</PRE>
+
+<!-- Is this in the right spot in this document? -->
+<H2><A name="opp.gate">An Opportunistic Gateway</A></H2>
+<H3><A NAME="14_7_1">Start from full opportunism</A></H3>
+<P>Full opportunism allows you to initiate and receive opportunistic
+ connections on your machine. The remaining instructions in this section
+ assume you have first set up full opportunism on your gateway using<A HREF="#opp.incoming">
+ these instructions</A>. Both sets of instructions require mailing DNS
+ records to your ISP. Collect DNS records for both the gateway (above)
+ and the subnet nodes (below) before contacting your ISP.</P>
+<H3><A NAME="14_7_2">Reverse DNS TXT records for each protected machine</A>
+</H3>
+<P>You need these so that your Opportunistic peers can:</P>
+<UL>
+<LI>discover the gateway's address, knowing only the IP address that
+ packets are bound for</LI>
+<LI>verify that the gateway is authorised to encrypt for that endpoint</LI>
+</UL>
+<P>On the gateway, generate a TXT record with:</P>
+<PRE>    ipsec showhostkey --txt 192.0.2.11</PRE>
+<P>Use your gateway address in place of 192.0.2.11.</P>
+<P>You should see (keys are trimmed for clarity throughout our example):</P>
+<PRE>    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;</PRE>
+<P><B>This MUST BE the same key as in your gateway's TXT record, or
+ nothing will work.</B></P>
+<P>In a text file, make one copy of this TXT record for each subnet
+ node:</P>
+<PRE>    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;
+                                                                                
+    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;
+                                                                                
+    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;</PRE>
+<P>Above each entry, insert a line like this:</P>
+<PRE>    98.2.0.192.in-addr.arpa. IN PTR arthur.example.com.</PRE>
+<P>It must include:</P>
+<UL>
+<LI>The subnet node's address in reverse map format. For example,
+ 192.0.2.120 becomes<VAR> 120.2.0.192.in-addr.arpa.</VAR>. Note the
+ final period.</LI>
+<LI><VAR>IN PTR</VAR></LI>
+<LI>The node's name, ie.<VAR> arthur.example.com.</VAR>. Note the final
+ period.</LI>
+</UL>
+<P>The result will be a file of TXT records, like this:</P>
+<PRE>    98.2.0.192.in-addr.arpa. IN PTR arthur.example.com.
+    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;
+                                                                                
+    99.2.0.192.in-addr.arpa. IN PTR ford.example.com.
+    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;
+                                                                                
+    100.2.0.192.in-addr.arpa. IN PTR trillian.example.com.
+    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;</PRE>
+<H3><A NAME="14_7_3">Publish your records</A></H3>
+<P>Ask your ISP to publish all the reverse DNS records you have
+ collected. There may be a delay of up to 48 hours as the records
+ propagate.</P>
+<H3><A NAME="14_7_4">...and test them</A></H3>
+<P>Check a couple of records with commands like this one:</P>
+<PRE>    ipsec verify --host ford.example.com
+    ipsec verify --host trillian.example.com</PRE>
+<P>The<VAR> verify</VAR> command checks for TXT records for both the
+ subnet host and its gateway. You should see output like:</P>
+<PRE>    ...
+    Looking for TXT in reverse map: 99.2.0.192.in-addr.arpa [OK]
+    ...
+    Looking for TXT in reverse map: 11.2.0.192.in-addr.arpa   [OK]
+    ...
+    Looking for TXT in reverse map: 100.2.0.192.in-addr.arpa [OK]
+    ...
+    Looking for TXT in reverse map: 11.2.0.192.in-addr.arpa   [OK]
+    ...</PRE>
+<H3><A NAME="14_7_5">No Configuration Needed</A></H3>
+<P>FreeS/WAN 2.x ships with a built-in, automatically enabled OE
+ connection<VAR> conn packetdefault</VAR> which applies OE, if possible,
+ to all outbound traffic routed through the FreeS/WAN box. The<A HREF="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5) manual</A> describes this connection in detail. While the
+ effect is much the same as<VAR> private-or-clear</VAR>, the
+ implementation is different: notably, it does not use policy groups.</P>
+<P>You can create more complex OE configurations for traffic forwarded
+ through a FreeS/WAN box, as explained in our<A HREF="#policygroups">
+ policy groups document</A>, or disable OE using<A HREF="#disable_policygroups">
+ these instructions</A>.</P>
+<H2><A name="extruded.config">Extruded Subnets</A></H2>
+<P>What we call<A href="glossary.html#extruded"> extruded subnets</A>
+ are a special case of<A href="glossary.html#VPN.gloss"> VPNs</A>.</P>
+<P>If your buddy has some unused IP addresses, in his subnet far off at
+ the other side of the Internet, he can loan them to you... provided
+ that the connection between you and him is fast enough to carry all the
+ traffic between your machines and the rest of the Internet. In effect,
+ he &quot;extrudes&quot; a part of his address space over the network to you, with
+ your Internet traffic appearing to originate from behind his Internet
+ gateway.</P>
+<P>As far as the Internet is concerned, your new extruded net is behind
+ your buddy's gateway. You route all your packets for the Internet at
+ large out his gateway, and receive return packets the same way. You
+ route your local packets locally.</P>
+<P>Suppose your friend has a.b.c.0/24 and wants to give you
+ a.b.c.240/28. The initial situation is:</P>
+<PRE>    subnet           gateway          Internet
+  a.b.c.0/24    a.b.c.1    p.q.r.s</PRE>
+ where anything from the Internet destined for any machine in a.b.c.0/24
+ is routed via p.q.r.s and that gateway knows what to do from there.
+<P>Of course it is quite normal for various smaller subnets to exist
+ behind your friend's gateway. For example, your friend's company might
+ have a.b.c.16/28=development, a.b.c.32/28=marketing and so on. The
+ Internet neither knows not cares about this; it just delivers packets
+ to the p.q.r.s and lets the gateway do whatever needs to be done from
+ there.</P>
+<P>What we want to do is take a subnet, perhaps a.b.c.240/28, out of
+ your friend's physical location<EM> while still having your friend's
+ gateway route to it</EM>. As far as the Internet is concerned, you
+ remain behind that gateway.</P>
+<PRE>    subnet           gateway          Internet       your gate  extruded
+
+  a.b.c.0/24   a.b.c.1     p.q.r.s              d.e.f.g         a.b.c.240/28                
+
+                           ========== tunnel ==========</PRE>
+<P>The extruded addresses have to be a complete subnet.</P>
+<P>In our example, the friend's security gateway is also his Internet
+ gateway, but this is not necessary. As long as all traffic from the
+ Internet to his addresses passes through the Internet gate, the
+ security gate could be a machine behind that. The IG would need to
+ route all traffic for the extruded subnet to the SG, and the SG could
+ handle the rest.</P>
+<P>First, configure your subnet using the extruded addresses. Your
+ security gateway's interface to your subnet needs to have an extruded
+ address (possibly using a Linux<A href="#virtual"> virtual interface</A>
+, if it also has to have a different address). Your gateway needs to
+ have a route to the extruded subnet, pointing to that interface. The
+ other machines at your site need to have addresses in that subnet, and
+ default routes pointing to your gateway.</P>
+<P>If any of your friend's machines need to talk to the extruded subnet,<EM>
+ they</EM> need to have a route for the extruded subnet, pointing at his
+ gateway.</P>
+<P>Then set up an IPsec subnet-to-subnet tunnel between your gateway and
+ his, with your subnet specified as the extruded subnet, and his subnet
+ specified as &quot;0.0.0.0/0&quot;.</P>
+<P>The tunnel description should be:</P>
+<PRE>conn extruded
+        left=p.q.r.s
+        leftsubnet=0.0.0.0/0
+        right=d.e.f.g
+        rightsubnet=a.b.c.0/28</PRE>
+<P>If either side was doing firewalling for the extruded subnet before
+ the IPsec connection is set up, you'll need to poke holes in your<A HREF="#firewall">
+ firewall</A> to allow packets through.</P>
+<P>And it all just works. Your SG routes traffic for 0.0.0.0/0 -- that
+ is, the whole Internet -- through the tunnel to his SG, which then
+ sends it onward as if it came from his subnet. When traffic for the
+ extruded subnet arrives at his SG, it gets sent through the tunnel to
+ your SG, which passes it to the right machine.</P>
+<P>Remember that when ipsec_manual or ipsec_auto takes a connection
+ down, it<EM> does not undo the route</EM> it made for that connection.
+ This lets you take a connection down and bring up a new one, or a
+ modified version of the old one, without having to rebuild the route it
+ uses and without any risk of packets which should use IPsec
+ accidentally going out in the clear. Because the route always points
+ into KLIPS, the packets will always go there. Because KLIPS temporarily
+ has no idea what to do with them (no eroute for them), they will be
+ discarded.</P>
+<P>If you<EM> do</EM> want to take the route down, this is what the
+ &quot;unroute&quot; operation in manual and auto is for. Just do an unroute after
+ doing the down.</P>
+<P>Note that the route for a connection may have replaced an existing
+ non-IPsec route. Nothing in Linux FreeS/WAN will put that pre-IPsec
+ route back. If you need it back, you have to create it with the route
+ command.</P>
+<H2><A name="roadvirt">Road Warrior with virtual IP address</A></H2>
+<P>Please note that<A HREF="http://www.freeswan.ca/download.php"> Super
+ FreeS/WAN</A> now features DHCP-over-IPsec, which is an alternate
+ procedure for Virtual IP address assignment.</P>
+<P></P>
+<P>Here is a mailing list message about another way to configure for
+ road warrior support:</P>
+<PRE>Subject: Re: linux-ipsec: understanding the vpn
+   Date: Thu, 28 Oct 1999 10:43:22 -0400
+   From: Irving Reid &lt;irving@nevex.com&gt;
+
+&gt;  local-------linux------internet------mobile
+&gt;  LAN        box                         user
+&gt;  ...
+
+&gt;  now when the mobile user connects to the linux box
+&gt;  it is given a virtual IP address, i have configured it to
+&gt;  be in the 10.x.x.x range. mobile user and linux box 
+&gt;  have a tunnel between them with these IP addresses.
+
+&gt;   Uptil this all is fine.
+
+If it is possible to configure your mobile client software *not* to
+use a virtual IP address, that will make your life easier. It is easier
+to configure FreeS/WAN to use the actual address the mobile user gets
+from its ISP.
+
+Unfortunately, some Windows clients don't let you choose.
+
+&gt;  what i would like to know is that how does the mobile
+&gt;  user communicate with other computers on the local
+&gt;  LAN , of course with the vpn ?
+
+&gt;   what IP address should the local LAN 
+&gt;  computers have ? I guess their default gateway 
+&gt;  should be the linux box ? and does the linux box need
+&gt;  to be a 2 NIC card box or one is fine.
+
+As someone else stated, yes, the Linux box would usually be the default
+IP gateway for the local lan.
+
+However...
+
+If you mobile user has software that *must* use a virtual IP address,
+the whole picture changes. Nobody has put much effort into getting
+FreeS/WAN to play well in this environment, but here's a sketch of one
+approach:
+
+Local Lan 1.0.0.0/24
+    |
+    +- Linux FreeS/WAN 1.0.0.2
+    |
+    | 1.0.0.1
+ Router
+    | 2.0.0.1
+    |
+Internet
+    |
+    | 3.0.0.1
+Mobile User
+      Virtual Address: 1.0.0.3
+
+Note that the Local Lan network (1.0.0.x) can be registered, routable
+addresses.
+
+Now, the Mobile User sets up an IPSec security association with the
+Linux box (1.0.0.2); it should ESP encapsulate all traffic to the
+network 1.0.0.x **EXCEPT** UDP port 500. 500/udp is required for the key
+negotiation, which needs to work outside of the IPSec tunnel.
+
+On the Linux side, there's a bunch of stuff you need to do by hand (for
+now). FreeS/WAN should correctly handle setting up the IPSec SA and
+routes, but I haven't tested it so this may not work...
+
+The FreeS/WAN conn should look like:
+
+conn mobile
+        right=1.0.0.2
+        rightsubnet=1.0.0.0/24
+        rightnexthop=1.0.0.1
+        left=0.0.0.0  # The infamous &quot;road warrior&quot;
+        leftsubnet=1.0.0.3/32
+
+Note that the left subnet contains *only* the remote host's virtual
+address.
+
+Hopefully the routing table on the FreeS/WAN box ends up looking like
+this:
+
+% netstat -rn
+Kernel IP routing table
+Destination     Gateway      Genmask         Flags   MSS Window  irtt Iface
+1.0.0.0         0.0.0.0      255.255.255.0   U      1500 0          0 eth0
+127.0.0.0       0.0.0.0      255.0.0.0       U      3584 0          0 lo
+0.0.0.0         1.0.0.1      0.0.0.0         UG     1500 0          0 eth0
+1.0.0.3         1.0.0.1      255.255.255.255 UG     1433 0          0 ipsec0
+
+So, if anybody sends a packet for 1.0.0.3 to the Linux box, it should
+get bundled up and sent through the tunnel. To get the packets for
+1.0.0.3 to the Linux box in the first place, you need to use &quot;proxy
+ARP&quot;.
+
+How this works is: when a host or router on the local Ethernet segment
+wants to send a packet to 1.0.0.3, it sends out an Ethernet level
+broadcast &quot;ARP request&quot;. If 1.0.0.3 was on the local LAN, it would
+reply, saying &quot;send IP packets for 1.0.0.3 to my Ethernet address&quot;.
+
+Instead, you need to set up the Linux box so that _it_ answers ARP
+requests for 1.0.0.3, even though that isn't its IP address. That
+convinces everyone else on the lan to send 1.0.0.3 packets to the Linux
+box, where the usual FreeS/WAN processing and routing take over.
+
+% arp -i eth0 -s 1.0.0.3 -D eth0 pub
+
+This says, if you see an ARP request on interface eth0 asking for
+1.0.0.3, respond with the Ethernet address of interface eth0.
+
+Now, as I said at the very beginning, if it is *at all* possible to
+configure your client *not* to use the virtual IP address, you can avoid
+this whole mess.</PRE>
+<H2><A name="dynamic">Dynamic Network Interfaces</A></H2>
+<P>Sometimes you have to cope with a situation where the network
+ interface(s) aren't all there at boot. The common example is notebooks
+ with PCMCIA.</P>
+<H3><A name="basicdyn">Basics</A></H3>
+<P>The key issue here is that the<VAR> config setup</VAR> section of the<VAR>
+ /etc/ipsec.conf</VAR> configuration file lists the connection between
+ ipsecN and hardware interfaces, in the<VAR> interfaces=</VAR> variable.
+ At any time when<VAR> ipsec setup start</VAR> or<VAR> ipsec setup
+ restart</VAR> is run this variable<STRONG> must</STRONG> correspond to
+ the current real situation. More precisely, it<STRONG> must not</STRONG>
+ mention any hardware interfaces which don't currently exist. The
+ difficulty is that an<VAR> ipsec setup start</VAR> command is normally
+ run at boot time so interfaces that are not up then are mis-handled.</P>
+<H3><A name="bootdyn">Boot Time</A></H3>
+<P>Normally, an<VAR> ipsec setup start</VAR> is run at boot time.
+ However, if the hardware situation at boot time is uncertain, one of
+ two things must be done.</P>
+<UL>
+<LI>One possibility is simply not to have IPsec brought up at boot time.
+ To do this:
+<PRE>        chkconfig --level 2345 ipsec off</PRE>
+ That's for modern Red Hats or other Linuxes with chkconfig. Systems
+ which lack this will require fiddling with symlinks in /etc/rc.d/rc?.d
+ or the equivalent.</LI>
+<LI>Another possibility is to bring IPsec up with no interfaces, which
+ is less aesthetically satisfying but simpler. Just put
+<PRE>        interfaces=</PRE>
+ in the configuration file. KLIPS and Pluto will be started, but won't
+ do anything.</LI>
+</UL>
+<H3><A name="changedyn">Change Time</A></H3>
+<P>When the hardware *is* in place, IPsec has to be made aware of it.
+ Someday there may be a nice way to do this.</P>
+<P>Right now, the way to do it is to fix the<VAR> /etc/ipsec.conf</VAR>
+ file appropriately, so<VAR> interfaces</VAR> reflects the new
+ situation, and then restart the IPsec subsystem. This does break any
+ existing IPsec connections.</P>
+<P>If IPsec wasn't brought up at boot time, do</P>
+<PRE>        ipsec setup start</PRE>
+ while if it was, do
+<PRE>        ipsec setup restart</PRE>
+ which won't be as quick.
+<P>If some of the hardware is to be taken out, before doing that, amend
+ the configuration file so interfaces no longer includes it, and do</P>
+<PRE>        ipsec setup restart</PRE>
+<P>Again, this breaks any existing connections.</P>
+<H2><A name="unencrypted">Unencrypted tunnels</A></H2>
+<P>Sometimes you might want to create a tunnel without encryption. Often
+ this is a bad idea, even if you have some data which need not be
+ private. See this<A href="#traffic.resist"> discussion</A>.</P>
+<P>The IPsec protocols provide two ways to do build such tunnels:</P>
+<DL>
+<DT>using ESP with null encryption</DT>
+<DD>not supported by FreeS/WAN</DD>
+<DT>using<A href="#AH"> AH</A> without<A href="#ESP"> ESP</A></DT>
+<DD>supported for manually keyed connections</DD>
+<DD>possible with explicit commands via<A href="manpage.d/ipsec_whack.8.html">
+ ipsec_whack(8)</A> (see this<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/02/msg00190.html">
+ list message</A>)</DD>
+<DD>not supported in the<A href="manpage.d/ipsec_auto.8.html">
+ ipsec_auto(8)</A> scripts.</DD>
+</DL>
+ One situation in which this comes up is when otherwise some data would
+ be encrypted twice. Alice wants a secure tunnel from her machine to
+ Bob's. Since she's behind one security gateway and he's behind another,
+ part of the tunnel that they build passes through the tunnel that their
+ site admins have built between the gateways. All of Alice and Bob's
+ messages are encrypted twice.
+<P>There are several ways to handle this.</P>
+<UL>
+<LI>Just accept the overhead of double encryption. The site admins might
+ choose this if any of the following apply:
+<UL>
+<LI>policy says encrypt everything (usually, it should)</LI>
+<LI>they don't entirely trust Alice and Bob (usually, if they don't have
+ to, they shouldn't)</LI>
+<LI>if they don't feel the saved cycles are worth the time they'd need
+ to build a non-encrypted tunnel for Alice and Bob's packets (often,
+ they aren't)</LI>
+</UL>
+</LI>
+<LI>Use a plain IP-in-IP tunnel. These are not well documented. A good
+ starting point is in the Linux kernel source tree, in
+ /usr/src/linux/drivers/net/README.tunnel.</LI>
+<LI>Use a manually-keyed AH-only tunnel.</LI>
+</UL>
+<P>Note that if Alice and Bob want end-to-end security, they must build
+ a tunnel end-to-end between their machines or use some other end-to-end
+ tool such as PGP or SSL that suits their data. The only question is
+ whether the admins build some special unencrypted tunnel for those
+ already-encrypted packets.</P>
+<HR>
+<H1><A name="install">Installing FreeS/WAN</A></H1>
+<P>This document will teach you how to install Linux FreeS/WAN. If your
+ distribution comes with Linux FreeS/WAN, we offer tips to get you
+ started.</P>
+<H2><A NAME="15_1">Requirements</A></H2>
+<P>To install FreeS/WAN you must:</P>
+<UL>
+<LI>be running Linux with the 2.4 or 2.2 kernel series. See this<A HREF="http://www.freeswan.ca/download.php#contact">
+ kernel compatibility table</A>.
+<BR>We also have experimental support for 2.6 kernels. Here are two
+ basic approaches:
+<UL>
+<LI> install FreeS/WAN, including its<A HREF="#parts"> KLIPS</A> kernel
+ code. This will remove the native IPsec stack and replace it with
+ KLIPS.</LI>
+<LI> install the FreeS/WAN<A HREF="#parts"> userland tools</A> (keying
+ daemon and supporting scripts) for use with<A HREF="http://lartc.org/howto/lartc.ipsec.html">
+ 2.6 kernel native IPsec</A>,</LI>
+</UL>
+ See also these<A HREF="2.6.known-issues"> known issues with 2.6</A>.</LI>
+<LI>have root access to your Linux box</LI>
+<LI>choose the version of FreeS/WAN you wish to install based on<A HREF="http://www.freeswan.org/mail.html">
+ mailing list reports</A>
+<!-- or 
+our updates page (coming soon)-->
+</LI>
+</UL>
+<H2><A NAME="15_2">Choose your install method</A></H2>
+<P>There are three basic ways to get FreeS/WAN onto your system:</P>
+<UL>
+<LI>activating and testing a FreeS/WAN that<A HREF="#distroinstall">
+ shipped with your Linux distribution</A></LI>
+<LI><A HREF="#rpminstall">RPM install</A></LI>
+<LI><A HREF="#srcinstall">Install from source</A></LI>
+</UL>
+<A NAME="distroinstall"></A>
+<H2><A NAME="15_3">FreeS/WAN ships with some Linuxes</A></H2>
+<P>FreeS/WAN comes with<A HREF="#distwith"> these distributions</A>.</P>
+<P>If you're running one of these, include FreeS/WAN in the choices you
+ make during installation, or add it later using the distribution's
+ tools.</P>
+<H3><A NAME="15_3_1">FreeS/WAN may be altered...</A></H3>
+<P>Your distribution may have integrated extra features, such as Andreas
+ Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup
+ script locations or directory names.</P>
+<H3><A NAME="15_3_2">You might need to create an authentication keypair</A>
+</H3>
+<P>If your FreeS/WAN came with your distribution, you may wish to
+ generate a fresh RSA key pair. FreeS/WAN will use these keys for
+ authentication.</P>
+<P> To do this, become root, and type:</P>
+<PRE>    ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
+    chmod 600 /etc/ipsec.secrets</PRE>
+<P>where you replace xy.example.com with your machine's fully-qualified
+ domain name. Generate some randomness, for example by wiggling your
+ mouse, to speed the process.</P>
+<P>The resulting ipsec.secrets looks like:</P>
+<PRE>: RSA   {
+        # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
+        # for signatures only, UNSAFE FOR ENCRYPTION
+        #pubkey=0sAQOFppfeE3cC7wqJi...
+        Modulus: 0x85a697de137702ef0...
+        # everything after this point is secret
+        PrivateExponent: 0x16466ea5033e807...
+        Prime1: 0xdfb5003c8947b7cc88759065...
+        Prime2: 0x98f199b9149fde11ec956c814...
+        Exponent1: 0x9523557db0da7a885af90aee...
+        Exponent2: 0x65f6667b63153eb69db8f300dbb...
+        Coefficient: 0x90ad00415d3ca17bebff123413fc518...
+        }
+# do not change the indenting of that &quot;}&quot;</PRE>
+<P>In the actual file, the strings are much longer.</P>
+<H3><A NAME="15_3_3">Start and test FreeS/WAN</A></H3>
+<P>You can now<A HREF="#starttest"> start FreeS/WAN and test whether
+ it's been successfully installed.</A>.</P>
+<A NAME="rpminstall"></A>
+<H2><A NAME="15_4">RPM install</A></H2>
+<P>These instructions are for a recent Red Hat with a stock Red Hat
+ kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If
+ you're running either, install using your distribution's tools.</P>
+<H3><A NAME="15_4_1">Download RPMs</A></H3>
+<P>Decide which functionality you need:</P>
+<UL>
+<LI>standard FreeS/WAN RPMs. Use these shortcuts:
+<BR>
+<UL>
+<LI>(for 2.6 kernels: userland only)
+<BR> ncftpget
+ ftp://ftp.xs4all.nl/pub/crypto/freeswan/binaries/RedHat-RPMs/\*userland*
+</LI>
+<LI>(for 2.4 kernels)
+<BR> ncftpget
+ ftp://ftp.xs4all.nl/pub/crypto/freeswan/binaries/RedHat-RPMs/`uname -r
+ | tr -d 'a-wy-z'`/\*</LI>
+<LI> or view all the offerings at our<A href="ftp://ftp.xs4all.nl/pub/crypto/freeswan/binaries/RedHat-RPMs">
+ FTP site</A>.</LI>
+</UL>
+</LI>
+<LI>unofficial<A href="http://www.freeswan.ca/download.php"> Super
+ FreeS/WAN</A> RPMs, which include Andreas Steffen's X.509 patch and
+ more. Super FreeS/WAN RPMs do not currently include<A HREF="#NAT.gloss">
+ Network Address Translation</A> (NAT) traversal, but Super FreeS/WAN
+ source does.</LI>
+</UL>
+<A NAME="2.6.rpm"></A>
+<P>For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:</P>
+<PRE>    freeswan-userland-2.04.9-0.i386.rpm</PRE>
+<P>Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please
+ see<A HREf="2.6.known-issues"> 2.6.known-issues</A>, and the latest<A HREF="http://www.freeswan.org/mail.html">
+ mailing list reports</A>.</P>
+<P>Change to your new FreeS/WAN directory, and make and install the</P>
+<P>For 2.4 kernels, get both kernel and userland RPMs. Check your kernel
+ version with</P>
+<PRE>    uname -r</PRE>
+<P>Get a kernel module which matches that version. For example:</P>
+<PRE>    freeswan-module-2.04_2.4.20_20.9-0.i386.rpm</PRE>
+<P>Note: These modules<B> will only work on the Red Hat kernel they were
+ built for</B>, since they are very sensitive to small changes in the
+ kernel.</P>
+<P>Get FreeS/WAN utilities to match. For example:</P>
+<PRE>    freeswan-userland-2.04_2.4.20_20.9-0.i386.rpm</PRE>
+<H3><A NAME="15_4_2">For freeswan.org RPMs: check signatures</A></H3>
+<P>While you're at our ftp site, grab the RPM signing key</P>
+<PRE>    freeswan-rpmsign.asc</PRE>
+<P>If you're running RedHat 8.x or later, import this key into the RPM
+ database:</P>
+<PRE>    rpm --import freeswan-rpmsign.asc</PRE>
+<P>For RedHat 7.x systems, you'll need to add it to your<A HREF="#PGP">
+ PGP</A> keyring:</P>
+<PRE>    pgp -ka freeswan-rpmsign.asc</PRE>
+<P>Check the digital signatures on both RPMs using:</P>
+<PRE>    rpm --checksig freeswan*.rpm </PRE>
+<P>You should see that these signatures are good:</P>
+<PRE>    freeswan-module-2.04_2.4.20_20.9-0.i386.rpm: pgp md5 OK
+    freeswan-userland-2.04_2.4.20_20.9-0.i386.rpm: pgp md5 OK</PRE>
+<H3><A NAME="15_4_3">Install the RPMs</A></H3>
+<P>Become root:</P>
+<PRE>    su</PRE>
+<P>For a first time install, use:</P>
+<PRE>    rpm -ivh freeswan*.rpm</PRE>
+<P>To upgrade existing RPMs (and keep all .conf files in place), use:</P>
+<PRE>    rpm -Uvh freeswan*.rpm</PRE>
+<P>If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter
+ problems, see<A HREF="#upgrading.rpms"> this note</A>.</P>
+<H3><A NAME="15_4_4">Start and Test FreeS/WAN</A></H3>
+<P>Now,<A HREF="#starttest"> start FreeS/WAN and test your install</A>.</P>
+<A NAME="srcinstall"></A>
+<H2><A NAME="15_5">Install from Source</A></H2>
+
+<!-- Most of this section, along with "Start and Test", can replace 
+INSTALL. -->
+<H3><A NAME="15_5_1">Decide what functionality you need</A></H3>
+<P>Your choices are:</P>
+<UL>
+<LI><A HREF="ftp://ftp.xs4all.nl/pub/crypto/freeswan">standard FreeS/WAN</A>
+,</LI>
+<LI>standard FreeS/WAN plus any of these<A HREF="#patch"> user-supported
+ patches</A>, or</LI>
+<LI><A HREF="http://www.freeswan.ca/download">Super FreeS/WAN</A>, an
+ unofficial FreeS/WAN pre-patched with many of the above. Provides
+ additional algorithms, X.509, SA deletion, dead peer detection, and<A HREF="#NAT.gloss">
+ Network Address Translation</A> (NAT) traversal.</LI>
+</UL>
+<H3><A NAME="15_5_2">Download FreeS/WAN</A></H3>
+<P>Download the source tarball you've chosen, along with any patches.</P>
+<H3><A NAME="15_5_3">For freeswan.org source: check its signature</A></H3>
+<P>While you're at our ftp site, get our source signing key</P>
+<PRE>    freeswan-sigkey.asc</PRE>
+<P>Add it to your PGP keyring:</P>
+<PRE>    pgp -ka freeswan-sigkey.asc</PRE>
+<P>Check the signature using:</P>
+<PRE>    pgp freeswan-2.04.tar.gz.sig freeswan-2.04.tar.gz</PRE>
+<P>You should see something like:</P>
+<PRE>    Good signature from user &quot;Linux FreeS/WAN Software Team (build@freeswan.org)&quot;.
+    Signature made 2002/06/26 21:04 GMT using 2047-bit key, key ID 46EAFCE1</PRE>
+
+<!-- Note to self: build@freeswan.org has angled brackets in the original.
+     Changed because it conflicts with HTML tags. -->
+<H3><A NAME="15_5_4">Untar, unzip</A></H3>
+<P>As root, unpack your FreeS/WAN source into<VAR> /usr/src</VAR>.</P>
+<PRE>    su
+    mv freeswan-2.04.tar.gz /usr/src
+    cd /usr/src
+    tar -xzf freeswan-2.04.tar.gz
+</PRE>
+<H3><A NAME="15_5_5">Patch if desired</A></H3>
+<P>Now's the time to add any patches. The contributor may have special
+ instructions, or you may simply use the patch command.</P>
+<H3><A NAME="15_5_6">... and Make</A></H3>
+<P>Choose one of the methods below.</P>
+<H4><A NAME="15_5_6_1">Userland-only Install for 2.6 kernels</A></H4>
+<A NAME="2.6.src"></A>
+<P>Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please
+ see<A HREf="2.6.known-issues"> 2.6.known-issues</A>, and the latest<A HREF="http://www.freeswan.org/mail.html">
+ mailing list reports</A>.</P>
+<P>Change to your new FreeS/WAN directory, and make and install the
+ FreeS/WAN userland tools.</P>
+<PRE>    cd /usr/src/freeswan-2.04
+    make programs
+    make install</PRE>
+<P>Now,<A HREF="#starttest"> start FreeS/WAN and test your install</A>.</P>
+<H4><A NAME="15_5_6_2">KLIPS install for 2.2, 2.4, or 2.6 kernels</A></H4>
+<A NAME="modinstall"></A>
+<P>To make a modular version of KLIPS, along with other FreeS/WAN
+ programs you'll need, use the command sequence below. This will change
+ to your new FreeS/WAN directory, make the FreeS/WAN module (and other
+ stuff), and install it all.</P>
+<PRE>    cd /usr/src/freeswan-2.04
+    make oldmod
+    make minstall</PRE>
+<P><A HREF="#starttest">Start FreeS/WAN and test your install</A>.</P>
+<P>To link KLIPS statically into your kernel (using your old kernel
+ settings), and install other FreeS/WAN components, do:</P>
+<PRE>    cd /usr/src/freeswan-2.04
+    make oldmod
+    make minstall</PRE>
+<P>Reboot your system and<A HREF="#testonly"> test your install</A>.</P>
+<P>For other ways to compile KLIPS, see our Makefile.</P>
+<A name="starttest"></A>
+<H2><A NAME="15_6">Start FreeS/WAN and test your install</A></H2>
+<P>Bring FreeS/WAN up with:</P>
+<PRE>    service ipsec start</PRE>
+<P>This is not necessary if you've rebooted.</P>
+<A name="testonly"></A>
+<H2><A NAME="15_7">Test your install</A></H2>
+<P>To check that you have a successful install, run:</P>
+<PRE>    ipsec verify</PRE>
+<P>You should see at least:</P>
+<PRE>
+    Checking your system to see if IPsec got installed and started correctly
+    Version check and ipsec on-path                             [OK]
+    Checking for KLIPS support in kernel                        [OK]
+    Checking for RSA private key (/etc/ipsec.secrets)           [OK]
+    Checking that pluto is running                              [OK]
+</PRE>
+<P>If any of these first four checks fails, see our<A href="#install.check">
+ troubleshooting guide</A>.</P>
+<H2><A NAME="15_8">Making FreeS/WAN play well with others</A></H2>
+<P>There are at least a couple of things on your system that might
+ interfere with FreeS/WAN, and now's a good time to check these:</P>
+<UL>
+<LI>Firewalling. You need to allow UDP 500 through your firewall, plus
+ ESP (protocol 50) and AH (protocol 51). For more information, see our
+ updated firewalls document (coming soon).</LI>
+<LI>Network address translation. Do not NAT the packets you will be
+ tunneling.</LI>
+</UL>
+<H2><A NAME="15_9">Configure for your needs</A></H2>
+<P>You'll need to configure FreeS/WAN for your local site. Have a look
+ at our<A HREF="quickstart.html"> opportunism quickstart guide</A> to
+ see if that easy method is right for your needs. Or, see how to<A HREF="config.html">
+ configure a network-to-network or Road Warrior style VPN</A>.</P>
+<HR>
+<H1><A NAME="config">How to configure FreeS/WAN</A></H1>
+<P>This page will teach you how to configure a simple network-to-network
+ link or a Road Warrior connection between two Linux FreeS/WAN boxes.</P>
+<P>See also these related documents:</P>
+<UL>
+<LI>our<A HREF="#quickstart"> quickstart</A> guide to<A HREF="#carpediem">
+ opportunistic encryption</A></LI>
+<LI>our guide to configuration with<A HREF="#policygroups"> policy
+ groups</A></LI>
+<LI>our<A HREF="#adv_config"> advanced configuration</A> document</LI>
+</UL>
+<P> The network-to-network setup allows you to connect two office
+ networks into one Virtual Private Network, while the Road Warrior
+ connection secures a laptop's telecommute to work. Our examples also
+ show the basic procedure on the Linux FreeS/WAN side where another
+ IPsec peer is in play.</P>
+<P> Shortcut to<A HREF="#config.netnet"> net-to-net</A>.
+<BR> Shortcut to<A HREF="#config.rw"> Road Warrior</A>.</P>
+<H2><A NAME="16_1">Requirements</A></H2>
+<P>To configure the network-to-network connection you must have:</P>
+<UL>
+<LI>two Linux gateways with static IPs</LI>
+<LI>a network behind each gate. Networks must have non-overlapping IP
+ ranges.</LI>
+<LI>Linux FreeS/WAN<A HREF="#install"> installed</A> on both gateways</LI>
+<LI><A HREF="http://www.tcpdump.org"><VAR>tcpdump</VAR></A> on the local
+ gate, to test the connection</LI>
+</UL>
+<P>For the Road Warrior you need:</P>
+<UL>
+<LI>one Linux box with a static IP</LI>
+<LI>a Linux laptop with a dynamic IP</LI>
+<LI>Linux FreeS/WAN installed on both</LI>
+<LI>for testing,<VAR> tcpdump</VAR> on your gateway or laptop</LI>
+</UL>
+<P>If both IPs are dynamic, your situation is a bit trickier. Your best
+ bet is a variation on the<A HREF="#config.rw"> Road Warrior</A>, as
+ described in<A HREF="http://lists.freeswan.org/archives/users/2003-October/msg00282.html">
+ this mailing list message</A>.</P>
+<H2><A name="config.netnet"></A>Net-to-Net connection</H2>
+<H3><A name="netnet.info.ex">Gather information</A></H3>
+<P>For each gateway, compile the following information:</P>
+<UL>
+<LI>gateway IP</LI>
+<LI>IP range of the subnet you will be protecting. This doesn't have to
+ be your whole physical subnet.</LI>
+<LI>a name by which that gateway can identify itself for IPsec
+ negotiations. Its form is a Fully Qualified Domain Name preceded by an
+ @ sign, ie. @xy.example.com.
+<BR> It does not need to be within a domain that you own. It can be a
+ made-up name.</LI>
+</UL>
+<H4><A NAME="16_2_1_1">Get your leftrsasigkey</A></H4>
+<P>On your local Linux FreeS/WAN gateway, print your IPsec public key:</P>
+<PRE>    ipsec showhostkey --left</PRE>
+<P>The output should look like this (with the key shortened for easy
+ reading):</P>
+<PRE>    # RSA 2048 bits   xy.example.com   Fri Apr 26 15:01:41 2002
+    leftrsasigkey=0sAQOnwiBPt...</PRE>
+<P>Don't have a key? Use<A HREF="manpage.d/ipsec_newhostkey.8.html"><VAR>
+ ipsec newhostkey</VAR></A> to create one.</P>
+<H4><A NAME="16_2_1_2">...and your rightrsasigkey</A></H4>
+<P>Get a console on the remote side:</P>
+<PRE>    ssh2 ab.example.com</PRE>
+<P>In that window, type:</P>
+<PRE>    ipsec showhostkey --right</PRE>
+<P>You'll see something like:</P>
+<PRE>    # RSA 2192 bits   ab.example.com   Thu May 16 15:26:20 2002
+    rightrsasigkey=0sAQOqH55O...</PRE>
+<H3><A NAME="16_2_2">Edit<VAR> /etc/ipsec.conf</VAR></A></H3>
+<P>Back on the local gate, copy our template to<VAR> /etc/ipsec.conf</VAR>
+. (on Mandrake,<VAR> /etc/freeswan/ipsec.conf</VAR>). Substitute the
+ information you've gathered for our example data.</P>
+<PRE>conn net-to-net
+    left=192.0.2.2                 # Local vitals
+    leftsubnet=192.0.2.128/29      # 
+    leftid=@xy.example.com         #   
+    leftrsasigkey=0s1LgR7/oUM...   #
+    leftnexthop=%defaultroute      # correct in many situations 
+    right=192.0.2.9                # Remote vitals
+    rightsubnet=10.0.0.0/24        #
+    rightid=@ab.example.com        # 
+    rightrsasigkey=0sAQOqH55O...   #
+    rightnexthop=%defaultroute     # correct in many situations
+    auto=add                       # authorizes but doesn't start this 
+                                   # connection at startup</PRE>
+<P> &quot;Left&quot; and &quot;right&quot; should represent the machines that have FreeS/WAN
+ installed on them, and &quot;leftsubnet&quot; and &quot;rightsubnet&quot; machines that are
+ being protected. /32 is assumed for left/right and left/rightsubnet
+ parameters.</P>
+<P>Copy<VAR> conn net-to-net</VAR> to the remote-side /etc/ipsec.conf.
+ If you've made no other modifications to either<VAR> ipsec.conf</VAR>,
+ simply:</P>
+<PRE>    scp2 ipsec.conf root@ab.example.com:/etc/ipsec.conf</PRE>
+<H3><A NAME="16_2_3">Start your connection</A></H3>
+<P>Locally, type:</P>
+<PRE>    ipsec auto --up net-to-net</PRE>
+<P>You should see:</P>
+<PRE>    104 &quot;net-net&quot; #223: STATE_MAIN_I1: initiate
+    106 &quot;net-net&quot; #223: STATE_MAIN_I2: sent MI2, expecting MR2
+    108 &quot;net-net&quot; #223: STATE_MAIN_I3: sent MI3, expecting MR3
+    004 &quot;net-net&quot; #223: STATE_MAIN_I4: ISAKMP SA established
+    112 &quot;net-net&quot; #224: STATE_QUICK_I1: initiate
+    004 &quot;net-net&quot; #224: STATE_QUICK_I2: sent QI2, IPsec SA established</PRE>
+<P>The important thing is<VAR> IPsec SA established</VAR>. If you're
+ unsuccessful, see our<A HREF="#trouble"> troubleshooting tips</A>.</P>
+<H3><A NAME="16_2_4">Do not MASQ or NAT packets to be tunneled</A></H3>
+<P>If you are using<A HREF="#masq"> IP masquerade</A> or<A HREF="#NAT.gloss">
+ Network Address Translation (NAT)</A> on either gateway, you must now
+ exempt the packets you wish to tunnel from this treatment. For example,
+ if you have a rule like:</P>
+<PRE>iptables -t nat -A POSTROUTING -o eth0 -s 10.0.0.0/24 -j MASQUERADE
+</PRE>
+<P>change it to something like:</P>
+<PRE>iptables -t nat -A POSTROUTING -o eth0 -s 10.0.0.0/24 -d \! 192.0.2.128/29 -j MASQUERADE</PRE>
+<P>This may be necessary on both gateways.</P>
+<H3><A NAME="16_2_5">Test your connection</A></H3>
+<P>Sit at one of your local subnet nodes (not the gateway), and ping a
+ subnet node on the other (again, not the gateway).</P>
+<PRE>    ping fileserver.toledo.example.com</PRE>
+<P>While still pinging, go to the local gateway and snoop your outgoing
+ interface, for example:</P>
+<PRE>    tcpdump -i ppp0</PRE>
+<P>You want to see ESP (Encapsulating Security Payload) packets moving<B>
+ back and forth</B> between the two gateways at the same frequency as
+ your pings:</P>
+<PRE>    19:16:32.046220 192.0.2.2 &gt; 192.0.2.9: ESP(spi=0x3be6c4dc,seq=0x3)
+    19:16:32.085630 192.0.2.9 &gt; 192.0.2.2: ESP(spi=0x5fdd1cf8,seq=0x6)</PRE>
+<P>If you see this, congratulations are in order! You have a tunnel
+ which will protect any IP data from one subnet to the other, as it
+ passes between the two gates. If not, go and<A HREF="#trouble">
+ troubleshoot</A>.</P>
+<P>Note: your new tunnel protects only net-net traffic, not
+ gateway-gateway, or gateway-subnet. If you need this (for example, if
+ machines on one net need to securely contact a fileserver on the IPsec
+ gateway), you'll need to create<A HREF="#adv_config"> extra connections</A>
+.</P>
+<H3><A NAME="16_2_6">Finishing touches</A></H3>
+<P>Now that your connection works, name it something sensible, like:</P>
+<PRE>conn winstonnet-toledonet</PRE>
+<P>To have the tunnel come up on-boot, replace</P>
+<PRE>    auto=add</PRE>
+<P>with:</P>
+<PRE>    auto=start</PRE>
+<P>Copy these changes to the other side, for example:</P>
+<PRE>    scp2 ipsec.conf root@ab.example.com:/etc/ipsec.conf</PRE>
+<P>Enjoy!</P>
+<H2><A name="config.rw"></A>Road Warrior Configuration</H2>
+<H3><A name="rw.info.ex">Gather information</A></H3>
+<P>You'll need to know:</P>
+<UL>
+<LI>the gateway's static IP</LI>
+<LI>the IP range of the subnet behind that gateway</LI>
+<LI>a name by which each side can identify itself for IPsec
+ negotiations. Its form is a Fully Qualified Domain Name preceded by an
+ @ sign, ie. @road.example.com.
+<BR> It does not need to be within a domain that you own. It can be a
+ made-up name.</LI>
+</UL>
+<H4><A NAME="16_3_1_1">Get your leftrsasigkey...</A></H4>
+<P>On your laptop, print your IPsec public key:</P>
+<PRE>    ipsec showhostkey --left</PRE>
+<P>The output should look like this (with the key shortened for easy
+ reading):</P>
+<PRE>    # RSA 2192 bits   road.example.com   Sun Jun  9 02:45:02 2002
+    leftrsasigkey=0sAQPIPN9uI...</PRE>
+<P>Don't have a key? See<A HREF="old_config.html#genrsakey"> these
+ instructions</A>.</P>
+<H4><A NAME="16_3_1_2">...and your rightrsasigkey</A></H4>
+<P>Get a console on the gateway:</P>
+<PRE>    ssh2 xy.example.com</PRE>
+<P>View the gateway's public key with:</P>
+<PRE>    ipsec showhostkey --right</PRE>
+<P>This will yield something like</P>
+<PRE>    # RSA 2048 bits   xy.example.com   Fri Apr 26 15:01:41 2002
+    rightrsasigkey=0sAQOnwiBPt...</PRE>
+<H3><A NAME="16_3_2">Customize<VAR> /etc/ipsec.conf</VAR></A></H3>
+<P>On your laptop, copy this template to<VAR> /etc/ipsec.conf</VAR>. (on
+ Mandrake,<VAR> /etc/freeswan/ipsec.conf</VAR>). Substitute the
+ information you've gathered for our example data.</P>
+<PRE>conn road
+    left=%defaultroute             # Picks up our dynamic IP 
+    leftnexthop=%defaultroute      # 
+    leftid=@road.example.com       # Local information
+    leftrsasigkey=0sAQPIPN9uI...   #
+    right=192.0.2.10               # Remote information
+    rightsubnet=10.0.0.0/24        #
+    rightid=@xy.example.com        # 
+    rightrsasigkey=0sAQOnwiBPt...  #
+    auto=add                       # authorizes but doesn't start this
+                                   # connection at startup</PRE>
+<P>The template for the gateway is different. Notice how it reverses<VAR>
+ left</VAR> and<VAR> right</VAR>, in keeping with our convention that<STRONG>
+ L</STRONG>eft is<STRONG> L</STRONG>ocal,<STRONG> R</STRONG>ight<STRONG>
+ R</STRONG>emote. Be sure to switch your rsasigkeys in keeping with
+ this.</P>
+<PRE>    ssh2 xy.example.com
+    vi /etc/ipsec.conf</PRE>
+<P>and add:</P>
+<PRE>conn road
+    left=192.0.2.2                 # Gateway's information
+    leftid=@xy.example.com         #
+    leftsubnet=192.0.2.128/29      #
+    leftrsasigkey=0sAQOnwiBPt...   #
+    rightnexthop=%defaultroute     # correct in many situations
+    right=%any                     # Wildcard: we don't know the laptop's IP
+    rightid=@road.example.com      #
+    rightrsasigkey=0sAQPIPN9uI...  #
+    auto=add                       # authorizes but doesn't start this
+                                   # connection at startup</PRE>
+<H3><A NAME="16_3_3">Start your connection</A></H3>
+<P>You must start the connection from the Road Warrior side. On your
+ laptop, type:</P>
+<PRE>    ipsec auto --start net-to-net</PRE>
+<P>You should see:</P>
+<PRE>104 &quot;net-net&quot; #223: STATE_MAIN_I1: initiate
+106 &quot;road&quot; #301: STATE_MAIN_I2: sent MI2, expecting MR2
+108 &quot;road&quot; #301: STATE_MAIN_I3: sent MI3, expecting MR3
+004 &quot;road&quot; #301: STATE_MAIN_I4: ISAKMP SA established
+112 &quot;road&quot; #302: STATE_QUICK_I1: initiate
+004 &quot;road&quot; #302: STATE_QUICK_I2: sent QI2, IPsec SA established</PRE>
+<P>Look for<VAR> IPsec SA established</VAR>. If you're unsuccessful, see
+ our<A HREF="#trouble"> troubleshooting tips</A>.</P>
+<H3><A NAME="16_3_4">Do not MASQ or NAT packets to be tunneled</A></H3>
+<P>If you are using<A HREF="#masq"> IP masquerade</A> or<A HREF="#NAT.gloss">
+ Network Address Translation (NAT)</A> on either gateway, you must now
+ exempt the packets you wish to tunnel from this treatment. For example,
+ if you have a rule like:</P>
+<PRE>iptables -t nat -A POSTROUTING -o eth0 -s 10.0.0.0/24 -j MASQUERADE
+</PRE>
+<P>change it to something like:</P>
+<PRE>iptables -t nat -A POSTROUTING -o eth0 -s 10.0.0.0/24 -d \! 192.0.2.128/29 -j MASQUERADE</PRE>
+<H3><A NAME="16_3_5">Test your connection</A></H3>
+<P>From your laptop, ping a subnet node behind the remote gateway. Do
+ not choose the gateway itself for this test.</P>
+<PRE>    ping ns.winston.example.com</PRE>
+<P>Snoop the packets exiting the laptop, with a command like:</P>
+<PRE>    tcpdump -i wlan0</PRE>
+<P>You have success if you see (Encapsulating Security Payload) packets
+ travelling<B> in both directions</B>:</P>
+<PRE>    19:16:32.046220 192.0.2.2 &gt; 192.0.2.9: ESP(spi=0x3be6c4dc,seq=0x3)
+    19:16:32.085630 192.0.2.9 &gt; 192.0.2.2: ESP(spi=0x5fdd1cf8,seq=0x6)</PRE>
+<P>If you do, great! Traffic between your Road Warrior and the net
+ behind your gateway is protected. If not, see our<A HREF="#trouble">
+ troubleshooting hints</A>.</P>
+<P>Your new tunnel protects only traffic addressed to the net, not to
+ the IPsec gateway itself. If you need the latter, you'll want to make
+ an<A HREF="#adv_config"> extra tunnel.</A>.</P>
+<H3><A NAME="16_3_6">Finishing touches</A></H3>
+<P>On both ends, name your connection wisely, like:</P>
+<PRE>conn mike-to-office</PRE>
+<P><B>On the laptop only,</B> replace</P>
+<PRE>    auto=add</PRE>
+<P>with:</P>
+<PRE>    auto=start</PRE>
+<P>so that you'll be connected on-boot.</P>
+<P>Happy telecommuting!</P>
+<H3><A NAME="16_3_7">Multiple Road Warriors</A></H3>
+<P>If you're using RSA keys, as we did in this example, you can add as
+ many Road Warriors as you like. The left/rightid parameter lets Linux
+ FreeS/WAN distinguish between multiple Road Warrior peers, each with
+ its own public key.</P>
+<P>The situation is different for shared secrets (PSK). During a PSK
+ negotiation, ID information is not available at the time Pluto is
+ trying to determine which secret to use, so, effectively, you can only
+ define one Roadwarrior connection. All your PSK road warriors must
+ therefore share one secret.</P>
+<H2><A NAME="16_4">What next?</A></H2>
+<P>Using the principles illustrated here, you can try variations such
+ as:</P>
+<UL>
+<LI>a telecommuter with a static IP</LI>
+<LI>a road warrior with a subnet behind it</LI>
+</UL>
+<P>Or, look at some of our<A HREF="#adv_config"> more complex
+ configuration examples.</A>.</P>
+<HR>
+<H1><A name="background">Linux FreeS/WAN background</A></H1>
+<P>This section discusses a number of issues which have three things in
+ common:</P>
+<UL>
+<LI>They are not specifically FreeS/WAN problems</LI>
+<LI>You may have to understand them to get FreeS/WAN working right</LI>
+<LI>They are not simple questions</LI>
+</UL>
+<P>Grouping them here lets us provide the explanations some users will
+ need without unduly complicating the main text.</P>
+<P>The explanations here are intended to be adequate for FreeS/WAN
+ purposes (please comment to the<A href="mail.html"> users mailing list</A>
+ if you don't find them so), but they are not trying to be complete or
+ definitive. If you need more information, see the references provided
+ in each section.</P>
+<H2><A name="dns.background">Some DNS background</A></H2>
+<P><A href="#carpediem">Opportunistic encryption</A> requires that the
+ gateway systems be able to fetch public keys, and other IPsec-related
+ information, from each other's DNS (Domain Name Service) records.</P>
+<P><A href="#DNS">DNS</A> is a distributed database that maps names to
+ IP addresses and vice versa.</P>
+<P>Much good reference material is available for DNS, including:</P>
+<UL>
+<LI>the<A href="http://www.linuxdoc.org/HOWTO/DNS-HOWTO.html"> DNS HowTo</A>
+</LI>
+<LI>the standard<A href="#DNS.book"> DNS reference</A> book</LI>
+<LI><A href="http://www.linuxdoc.org/LDP/nag2/index.html">Linux Network
+ Administrator's Guide</A></LI>
+<LI><A href="http://www.nominum.com/resources/whitepapers/bind-white-paper.html">
+BIND overview</A></LI>
+<LI><A href="http://www.nominum.com/resources/documentation/Bv9ARM.pdf">
+BIND 9 Administrator's Reference</A></LI>
+</UL>
+<P>We give only a brief overview here, intended to help you use DNS for
+ FreeS/WAN purposes.</P>
+<H3><A name="forward.reverse">Forward and reverse maps</A></H3>
+<P>Although the implementation is distributed, it is often useful to
+ speak of DNS as if it were just two enormous tables:</P>
+<UL>
+<LI>the forward map: look up a name, get an IP address</LI>
+<LI>the reverse map: look up an IP address, get a name</LI>
+</UL>
+<P>Both maps can optionally contain additional data. For opportunistic
+ encryption, we insert the data need for IPsec authentication.</P>
+<P>A system named gateway.example.com with IP address 10.20.30.40 should
+ have at least two DNS records, one in each map:</P>
+<DL>
+<DT>gateway.example.com. IN A 10.20.30.40</DT>
+<DD>used to look up the name and get an IP address</DD>
+<DT>40.30.20.10.in-addr.arpa. IN PTR gateway.example.com.</DT>
+<DD>used for reverse lookups, looking up an address to get the
+ associated name. Notice that the digits here are in reverse order; the
+ actual address is 10.20.30.40 but we use 40.30.20.10 here.</DD>
+</DL>
+<H3><A NAME="17_1_2">Hierarchy and delegation</A></H3>
+<P>For both maps there is a hierarchy of DNS servers and a system of
+ delegating authority so that, for example:</P>
+<UL>
+<LI>the DNS administrator for example.com can create entries of the form<VAR>
+ name</VAR>.example.com</LI>
+<LI>the example.com admin cannot create an entry for counterexample.com;
+ only someone with authority for .com can do that</LI>
+<LI>an admin might have authority for 20.10.in-addr.arpa.</LI>
+<LI>in either map, authority can be delegated
+<UL>
+<LI>the example.com admin could give you authority for
+ westcoast.example.com</LI>
+<LI>the 20.10.in-addr.arpa admin could give you authority for
+ 30.20.10.in-addr.arpa</LI>
+</UL>
+</LI>
+</UL>
+<P>DNS zones are the units of delegation. There is a hierarchy of zones.</P>
+<H3><A NAME="17_1_3">Syntax of DNS records</A></H3>
+<P>Returning to the example records:</P>
+<PRE>        gateway.example.com. IN A 10.20.30.40
+        40.30.20.10.in-addr.arpa. IN PTR gateway.example.com.</PRE>
+<P>some syntactic details are:</P>
+<UL>
+<LI>the IN indicates that these records are for<STRONG> In</STRONG>
+ternet addresses</LI>
+<LI>The final periods in '.com.' and '.arpa.' are required. They
+ indicate the root of the domain name system.</LI>
+</UL>
+<P>The capitalised strings after IN indicate the type of record.
+ Possible types include:</P>
+<UL>
+<LI><STRONG>A</STRONG>ddress, for forward lookups</LI>
+<LI><STRONG>P</STRONG>oin<STRONG>T</STRONG>e<STRONG>R</STRONG>, for
+ reverse lookups</LI>
+<LI><STRONG>C</STRONG>anonical<STRONG> NAME</STRONG>, records to support
+ aliasing, multiple names for one address</LI>
+<LI><STRONG>M</STRONG>ail e<STRONG>X</STRONG>change, used in mail
+ routing</LI>
+<LI><STRONG>SIG</STRONG>nature, used in<A href="#SDNS"> secure DNS</A></LI>
+<LI><STRONG>KEY</STRONG>, used in<A href="#SDNS"> secure DNS</A></LI>
+<LI><STRONG>T</STRONG>e<STRONG>XT</STRONG>, a multi-purpose record type</LI>
+</UL>
+<P>To set up for opportunistic encryption, you add some TXT records to
+ your DNS data. Details are in our<A href="quickstart.html"> quickstart</A>
+ document.</P>
+<H3><A NAME="17_1_4">Cacheing, TTL and propagation delay</A></H3>
+<P>DNS information is extensively cached. With no caching, a lookup by
+ your system of &quot;www.freeswan.org&quot; might involve:</P>
+<UL>
+<LI>your system asks your nameserver for &quot;www.freeswan.org&quot;</LI>
+<LI>local nameserver asks root server about &quot;.org&quot;, gets reply</LI>
+<LI>local nameserver asks .org nameserver about &quot;freeswan.org&quot;, gets
+ reply</LI>
+<LI>local nameserver asks freeswan.org nameserver about
+ &quot;www.freeswan.org&quot;, gets reply</LI>
+</UL>
+<P>However, this can be a bit inefficient. For example, if you are in
+ the Phillipines, the closest a root server is in Japan. That might send
+ you to a .org server in the US, and then to freeswan.org in Holland. If
+ everyone did all those lookups every time they clicked on a web link,
+ the net would grind to a halt.</P>
+<P>Nameservers therefore cache information they look up. When you click
+ on another link at www.freeswan.org, your local nameserver has the IP
+ address for that server in its cache, and no further lookups are
+ required.</P>
+<P>Intermediate results are also cached. If you next go to
+ lists.freeswan.org, your nameserver can just ask the freeswan.org
+ nameserver for that address; it does not need to query the root or .org
+ nameservers because it has a cached address for the freeswan.org zone
+ server.</P>
+<P>Of course, like any cacheing mechanism, this can create problems of
+ consistency. What if the administrator for freeswan.org changes the IP
+ address, or the authentication key, for www.freeswan.org? If you use
+ old information from the cache, you may get it wrong. On the other
+ hand, you cannot afford to look up fresh information every time. Nor
+ can you expect the freeswan.org server to notify you; that isn't in the
+ protocols.</P>
+<P>The solution that is in the protocols is fairly simple. Cacheable
+ records are marked with Time To Live (TTL) information. When the time
+ expires, the caching server discards the record. The next time someone
+ asks for it, the server fetches a fresh copy. Of course, a server may
+ also discard records before their TTL expires if it is running out of
+ cache space.</P>
+<P>This implies that there will be some delay before the new version of
+ a changed record propagates around the net. Until the TTLs on all
+ copies of the old record expire, some users will see it because that is
+ what is in their cache. Other users may see the new record immediately
+ because they don't have an old one cached.</P>
+<H2><A name="MTU.trouble">Problems with packet fragmentation</A></H2>
+<P>It seems, from mailing list reports, to be moderately common for
+ problems to crop up in which small packets pass through the IPsec
+ tunnels just fine but larger packets fail.</P>
+<P>These problems are caused by various devices along the way
+ mis-handling either packet fragments or<A href="#pathMTU"> path MTU
+ discovery</A>.</P>
+<P>IPsec makes packets larger by adding an ESP or AH header. This can
+ tickle assorted bugs in fragment handling in routers and firewalls, or
+ in path MTU discovery mechanisms, and cause a variety of symptoms which
+ are both annoying and, often, quite hard to diagnose.</P>
+<P>An explanation from project technical lead Henry Spencer:</P>
+<PRE>The problem is IP fragmentation; more precisely, the problem is that the
+second, third, etc. fragments of an IP packet are often difficult for
+filtering mechanisms to classify.
+
+Routers cannot rely on reassembling the packet, or remembering what was in
+earlier fragments, because the fragments may be out of order or may even
+follow different routes.  So any general, worst-case filtering decision
+pretty much has to be made on each fragment independently.  (If the router
+knows that it is the only route to the destination, so all fragments
+*must* pass through it, reassembly would be possible... but most routers
+don't want to bother with the complications of that.)
+
+All fragments carry roughly the original IP header, but any higher-level
+header is (for IP purposes) just the first part of the packet data... so
+only the first fragment carries that.  So, for example, on examining the
+second fragment of a TCP packet, you could tell that it's TCP, but not
+what port number it is destined for -- that information is in the TCP
+header, which appears in the first fragment only. 
+
+The result of this classification difficulty is that stupid routers and
+over-paranoid firewalls may just throw fragments away.  To get through
+them, you must reduce your MTU enough that fragmentation will not occur.
+(In some cases, they might be willing to attempt reassembly, but have very
+limited resources to devote to it, meaning that packets must be small and
+fragments few in number, leading to the same conclusion:  smaller MTU.)</PRE>
+<P>In addition to the problem Henry describes, you may also have trouble
+ with<A href="#pathMTU"> path MTU discovery</A>.</P>
+<P>By default, FreeS/WAN uses a large<A href="#MTU"> MTU</A> for the
+ ipsec device. This avoids some problems, but may complicate others.
+ Here's an explanation from Claudia:</P>
+<PRE>Here are a couple of pieces of background information. Apologies if you
+have seen these already. An excerpt from one of my old posts:
+
+    An MTU of 16260 on ipsec0 is usual. The IPSec device defaults to this 
+    high MTU so that it does not fragment incoming packets before encryption 
+    and encapsulation. If after IPSec processing packets are larger than 1500,
+    [ie. the mtu of eth0] then eth0 will fragment them. 
+
+    Adding IPSec headers adds a certain number of bytes to each packet. 
+    The MTU of the IPSec interface refers to the maximum size of the packet
+    before the IPSec headers are added. In some cases, people find it helpful 
+    to set ipsec0's MTU to 1500-(IPSec header size), which IIRC is about 1430.
+
+    That way, the resulting encapsulated packets don't exceed 1500. On most 
+    networks, packets less than 1500 will not need to be fragmented.
+
+and... (from Henry Spencer)
+
+    The way it *ought* to work is that the MTU advertised by the ipsecN
+    interface should be that of the underlying hardware interface, less a
+    pinch for the extra headers needed. 
+
+    Unfortunately, in certain situations this breaks many applications.
+    There is a widespread implicit assumption that the smallest MTUs are 
+    at the ends of paths, not in the middle, and another that MTUs are 
+    never less than 1500.  A lot of code is unprepared to handle paths 
+    where there is an &quot;interior minimum&quot; in the MTU, especially when it's 
+    less than 1500. So we advertise a big MTU and just let the resulting 
+    big packets fragment.
+
+This usually works, but we do get bitten in cases where some intermediate
+point can't handle all that fragmentation.  We can't win on this one.</PRE>
+<P>The MTU can be changed with an<VAR> overridemtu=</VAR> statement in
+ the<VAR> config setup</VAR> section of<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf.5</A>.</P>
+<P>For a discussion of MTU issues and some possible solutions using
+ Linux advanced routing facilities, see the<A href="http://www.linuxguruz.org/iptables/howto/2.4routing-15.html#ss15.6">
+ Linux 2.4 Advanced Routing HOWTO</A>. For a discussion of MTU and NAT
+ (Network Address Translation), see<A HREF="http://harlech.math.ucla.edu/services/ipsec.html">
+ James Carter's MTU notes</A>.</P>
+<H2><A name="nat.background">Network address translation (NAT)</A></H2>
+<P><STRONG>N</STRONG>etwork<STRONG> A</STRONG>ddress<STRONG> T</STRONG>
+ranslation is a service provided by some gateway machines. Calling it
+ NAPT (adding the word<STRONG> P</STRONG>ort) would be more precise, but
+ we will follow the widespread usage.</P>
+<P>A gateway doing NAT rewrites the headers of packets it is forwarding,
+ changing one or more of:</P>
+<UL>
+<LI>source address</LI>
+<LI>source port</LI>
+<LI>destination address</LI>
+<LI>destination port</LI>
+</UL>
+<P>On Linux 2.4, NAT services are provided by the<A href="http://netfilter.samba.org">
+ netfilter(8)</A> firewall code. There are several<A href="http://netfilter.samba.org/documentation/index.html#HOWTO">
+ Netfilter HowTos</A> including one on NAT.</P>
+<P>For older versions of Linux, this was referred to as &quot;IP masquerade&quot;
+ and different tools were used. See this<A href="http://www.e-infomax.com/ipmasq/">
+ resource page</A>.</P>
+<P>Putting an IPsec gateway behind a NAT gateway is not recommended. See
+ our<A href="#NAT"> firewalls document</A>.</P>
+<H3><A NAME="17_3_1">NAT to non-routable addresses</A></H3>
+<P>The most common application of NAT uses private<A href="#non-routable">
+ non-routable</A> addresses.</P>
+<P>Often a home or small office network will have:</P>
+<UL>
+<LI>one connection to the Internet</LI>
+<LI>one assigned publicly visible IP address</LI>
+<LI>several machines that all need access to the net</LI>
+</UL>
+<P>Of course this poses a problem since several machines cannot use one
+ address. The best solution might be to obtain more addresses, but often
+ this is impractical or uneconomical.</P>
+<P>A common solution is to have:</P>
+<UL>
+<LI><A href="#non-routable">non-routable</A> addresses on the local
+ network</LI>
+<LI>the gateway machine doing NAT</LI>
+<LI>all packets going outside the LAN rewritten to have the gateway as
+ their source address</LI>
+</UL>
+<P>The client machines are set up with reserved<A href="#non-routable">
+ non-routable</A> IP addresses defined in RFC 1918. The masquerading
+ gateway, the machine with the actual link to the Internet, rewrites
+ packet headers so that all packets going onto the Internet appear to
+ come from one IP address, that of its Internet interface. It then gets
+ all the replies, does some table lookups and more header rewriting, and
+ delivers the replies to the appropriate client machines.</P>
+<P>As far as anyone else on the Internet is concerned, the systems
+ behind the gateway are completely hidden. Only one machine with one IP
+ address is visible.</P>
+<P>For IPsec on such a gateway, you can entirely ignore the NAT in:</P>
+<UL>
+<LI><A href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</A></LI>
+<LI>firewall rules affecting your Internet-side interface</LI>
+</UL>
+<P>Those can be set up exactly as they would be if your gateway had no
+ other systems behind it.</P>
+<P>You do, however, have to take account of the NAT in firewall rules
+ which affect packet forwarding.</P>
+<H3><A NAME="17_3_2">NAT to routable addresses</A></H3>
+<P>NAT to routable addresses is also possible, but is less common and
+ may make for rather tricky routing problems. We will not discuss it
+ here. See the<A href="http://netfilter.samba.org/documentation/index.html#HOWTO">
+ Netfilter HowTos</A>.</P>
+<HR>
+<H1><A name="user.examples">FreeS/WAN script examples</A></H1>
+ This file is intended to hold a collection of user-written example
+ scripts or configuration files for use with FreeS/WAN.
+<P> So far it has only one entry.</P>
+<H2><A name="poltorak">Poltorak's Firewall script</A></H2>
+<PRE>
+From: Poltorak Serguei &lt;poltorak@dataforce.net&gt;
+Subject: [Users] Using FreeS/WAN
+Date: Tue, 16 Oct 2001
+
+Hello.
+
+I'm using FreeS/WAN IPsec for half a year. I learned a lot of things about
+it and I think it would be interesting for someone to see the result of my
+experiments and usage of FreeS/WAN. If you find a mistake in this
+file, please e-mail me. And excuse me for my english... I'm learning.. :)
+
+I'll talk about vary simple configuration:
+
+addresses prefix = 192.168
+
+    lan1          sgw1     .0.0/24 (Internet)       sgw2            lan2
+  .1.0/24---[ .1.1 ; .0.1 ]===================[ .0.10 ; . 2.10 ]---.2.0/24
+
+
+We need to let lan1 see lan2 across Internet like it is behind sgw1. The
+same for lan2. And we need to do IPX bridge for Novel Clients and NDS
+synchronization.
+
+my config:
+------------------- ipsec.conf -------------------
+conn lan1-lan2
+        type=tunnel
+        compress=yes
+        #-------------------
+        left=192.168.0.1
+        leftsubnet=192.168.1.0/24
+        #-------------------
+        right=192.168.0.10
+        rightsubnet=192.168.2.0/24
+        #-------------------
+        auth=esp
+        authby=secret
+--------------- end of ipsec.conf ----------------
+
+ping .2.x from .1.y   (y != 1)
+It works?? Fine. Let's continue...
+
+Why y != 1 ?? Because kernel of sgw1 have 2 IP addresses and it will choose
+the first IP (which is used to go to Internet) .0.1 and the packet won't go
+through IPsec tunnel :(  But if do ping on .1.1 kernel will respond from
+that address (.1.1) and the packet will be tunneled. The same problem occurred then
+.2.x sends a packet to .1.2 which is down at the moment. What happens? .1.1
+sends ARP requesting .1.2... after 3 tries it send to .2.x an destunreach,
+but from his &quot;natural&quot; IP or .0.1 . So the error message won't be delivered!
+It's a big problem...
+
+Resolution... One can manipulate with ipsec0 or ipsec0:0 to solve the
+problem (if ipsec0 has .1.1 kernel will send packets correctly), but there
+are powerful and elegant iproute2 :) We simply need to change source address
+of packet that goes to other secure lan. This is done with
+
+ip route replace 192.168.2.0/24 via 192.168.0.10 dev ipsec0 src 192.168.1.1
+
+Cool!! Now it works!!
+
+The second step. We want install firewall on sgw1 and sgw2. Encryption of 
+traffic without security isn't a good idea. I don't use {left|right}firewall, 
+because I'm running firewall from init scripts.
+
+We want IPsec data between lan1-lan2, some ICMP errors (destination
+unreachable, TTL exceeded, parameter problem and source quench), replying on 
+pings from both lans and Internet, ipxtunnel data for IPX and of course SSH
+between sgw1 and sgw2 and from/to one specified host.
+
+I'm using ipchains. With iptables there are some changes.
+
+---------------- rc.firewall ---------------------
+#!/bin/sh
+#
+# Firewall for IPsec lan1-lan2
+#
+
+IPC=/sbin/ipchains
+ANY=0.0.0.0/0
+
+# left
+SGW1_EXT=192.168.0.1
+SGW1_INT=192.168.1.1
+LAN1=192.168.1.0/24
+
+# right
+SGW2_EXT=192.168.0.10
+SGW2_INT=192.168.2.10
+LAN2=192.168.2.0/24
+
+# SSH from and to this host
+SSH_PEER_HOST=_SOME_HOST_
+
+# this is for left. exchange these values for right.
+MY_EXT=$SGW1_EXT
+MY_INT=$SGW1_INT
+PEER_EXT=$SGW2_EXT
+PEER_INT=$SGW2_INT
+INT_IF=eth1
+EXT_IF=eth0
+IPSEC_IF=ipsec0
+MY_LAN=$LAN1
+PEER_LAN=$LAN2
+
+$IPC -F
+$IPC -P input DENY
+$IPC -P forward DENY
+$IPC -P output DENY
+
+# Loopback traffic
+$IPC -A input -i lo -j ACCEPT
+$IPC -A output -i lo -j ACCEPT
+
+# for IPsec SGW1-SGW2
+## IKE
+$IPC -A input -p udp -s $PEER_EXT 500 -d $MY_EXT 500 -i $EXT_IF -j ACCEPT
+$IPC -A output -p udp -s $MY_EXT 500 -d $PEER_EXT 500 -i $EXT_IF -j ACCEPT
+## ESP
+$IPC -A input -p 50 -s $PEER_EXT -d $MY_EXT -i $EXT_IF -j ACCEPT
+### we don't need this line ### $IPC -A output -p 50 -s $MY_EXT -d $PEER_EXT -i $EXT_IF -j ACCEPT
+## forward LAN1-LAN2
+$IPC -A forward -s $MY_LAN -d $PEER_LAN -i $IPSEC_IF -j ACCEPT
+$IPC -A forward -s $PEER_LAN -d $MY_LAN -i $INT_IF -j ACCEPT
+$IPC -A output -s $PEER_LAN -d $MY_LAN -i $INT_IF -j ACCEPT
+$IPC -A input -s $PEER_LAN -d $MY_LAN -i $IPSEC_IF -j ACCEPT
+$IPC -A input -s $MY_LAN -d $PEER_LAN -i $INT_IF -j ACCEPT
+$IPC -A output -s $MY_LAN -d $PEER_LAN -i $IPSEC_IF -j ACCEPT
+
+# ICMP
+#
+## Dest unreachable
+### from/to Internet
+$IPC -A input -p icmp --icmp-type destination-unreachable -s $ANY -d $MY_EXT -i $EXT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type destination-unreachable -s $MY_EXT -d $ANY -i $EXT_IF -j ACCEPT
+### from/to Lan
+$IPC -A input -p icmp --icmp-type destination-unreachable -s $ANY -d $MY_INT -i $INT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type destination-unreachable -s $MY_INT -d $ANY -i $INT_IF -j ACCEPT
+### from/to Peer Lan
+$IPC -A input -p icmp --icmp-type destination-unreachable -s $ANY -d $MY_INT -i $IPSEC_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type destination-unreachable -s $MY_INT -d $ANY -i $IPSEC_IF -j ACCEPT
+#
+## Source quench
+### from/to Internet
+$IPC -A input -p icmp --icmp-type source-quench -s $ANY -d $MY_EXT -i $EXT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type source-quench -s $MY_EXT -d $ANY -i $EXT_IF -j ACCEPT
+### from/to Lan
+$IPC -A input -p icmp --icmp-type source-quench -s $ANY -d $MY_INT -i $INT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type source-quench -s $MY_INT -d $ANY -i $INT_IF -j ACCEPT
+### from/to Peer Lan
+$IPC -A input -p icmp --icmp-type source-quench -s $ANY -d $MY_INT -i $IPSEC_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type source-quench -s $MY_INT -d $ANY -i $IPSEC_IF -j ACCEPT
+#
+## Parameter problem
+### from/to Internet
+$IPC -A input -p icmp --icmp-type parameter-problem -s $ANY -d $MY_EXT -i $EXT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type parameter-problem -s $MY_EXT -d $ANY -i $EXT_IF -j ACCEPT
+### from/to Lan
+$IPC -A input -p icmp --icmp-type parameter-problem -s $ANY -d $MY_INT -i $INT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type parameter-problem -s $MY_INT -d $ANY -i $INT_IF -j ACCEPT
+### from/to Peer Lan
+$IPC -A input -p icmp --icmp-type parameter-problem -s $ANY -d $MY_INT -i $IPSEC_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type parameter-problem -s $MY_INT -d $ANY -i $IPSEC_IF -j ACCEPT
+#
+## Time To Live exceeded
+### from/to Internet
+$IPC -A input -p icmp --icmp-type time-exceeded -s $ANY -d $MY_EXT -i $EXT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type time-exceeded -s $MY_EXT -d $ANY -i $EXT_IF -j ACCEPT
+### to Lan
+$IPC -A input -p icmp --icmp-type time-exceeded -s $ANY -d $MY_INT -i $INT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type time-exceeded -s $MY_INT -d $ANY -i $INT_IF -j ACCEPT
+### to Peer Lan
+$IPC -A input -p icmp --icmp-type time-exceeded -s $ANY -d $MY_INT -i $IPSEC_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type time-exceeded -s $MY_INT -d $ANY -i $IPSEC_IF -j ACCEPT
+
+# ICMP PINGs
+## from Internet
+$IPC -A input -p icmp -s $ANY -d $MY_EXT --icmp-type echo-request  -i $EXT_IF -j ACCEPT
+$IPC -A output -p icmp -s $MY_EXT -d $ANY --icmp-type echo-reply  -i $EXT_IF -j ACCEPT
+## from LAN
+$IPC -A input -p icmp -s $ANY -d $MY_INT --icmp-type echo-request -i $INT_IF -j ACCEPT
+$IPC -A output -p icmp -s $MY_INT -d $ANY --icmp-type echo-reply  -i $INT_IF -j ACCEPT
+## from Peer LAN
+$IPC -A input -p icmp -s $ANY -d $MY_INT --icmp-type echo-request -i $IPSEC_IF -j ACCEPT
+$IPC -A output -p icmp -s $MY_INT -d $ANY --icmp-type echo-reply  -i $IPSEC_IF -j ACCEPT
+
+# SSH
+## from SSH_PEER_HOST
+$IPC -A input -p tcp -s $SSH_PEER_HOST -d $MY_EXT 22 -i $EXT_IF -j ACCEPT
+$IPC -A output -p tcp \! -y -s $MY_EXT 22 -d $SSH_PEER_HOST -i $EXT_IF -j ACCEPT
+## to SSH_PEER_HOST
+$IPC -A input -p tcp \! -y -s $SSH_PEER_HOST 22 -d $MY_EXT -i $EXT_IF -j ACCEPT
+$IPC -A output -p tcp -s $MY_EXT -d $SSH_PEER_HOST 22 -i $EXT_IF -j ACCEPT
+## from PEER
+$IPC -A input -p tcp -s $PEER_EXT -d $MY_EXT 22 -i $EXT_IF -j ACCEPT
+$IPC -A output -p tcp \! -y -s $MY_EXT 22 -d $PEER_EXT -i $EXT_IF -j ACCEPT
+## to PEER
+$IPC -A input -p tcp \! -y -s $PEER_EXT 22 -d $MY_EXT -i $EXT_IF -j ACCEPT
+$IPC -A output -p tcp -s $MY_EXT -d $PEER_EXT 22 -i $EXT_IF -j ACCEPT
+
+# ipxtunnel
+$IPC -A input -p udp -s $PEER_INT 2005 -d $MY_INT 2005 -i $IPSEC_IF -j ACCEPT
+$IPC -A output -p udp -s $MY_INT 2005 -d $PEER_INT 2005 -i $IPSEC_IF -j ACCEPT
+
+---------------- end of rc.firewall ----------------------
+
+To understand this we need to look on this scheme:
+
+           ++-----------------------&lt;----------------------------+
+           || ipsec0                                             |
+           \/                                                    |
+ eth0  +--------+    /---------/ yes  /---------/ yes +-----------------------+
+------&gt;| INPUT  |--&gt;/ ?local? /-----&gt;/ ?IPsec? /-----&gt;| decrypt decapsulate |
+ eth1  +--------+  /---------/      /---------/       +-----------------------+
+                       || no            || no
+                       \/               \/
+                  +----------+      +---------+        +-------+
+                  | routing  |      |  local  |        | local |
+                  | decision |      | deliver |        | send  |
+                  +----------+      +---------+        +-------+
+                       ||                                 ||
+                       \/                                 \/
+                   +---------+                       +----------+
+                   | forward |                       | routing  |
+                   +---------+                       | decision |
+                       ||                            +----------+
+                       ||                                  ||
+                       ++----------------&lt;-----------------++
+                       ||
+                       \/
+                   +--------+ eth0
+                   | OUTPUT | eth1
+                   +--------+ ipsec0
+                       ||
+                       \/
+                   /---------/ yes +-----------------------+
+                  / ?IPsec? /-----&gt;| encrypt encapsulate |
+                 /---------/       +-----------------------+
+                      || no                    ||
+                      ||                       ||
+                      ||                       \/   eth0, eth1
+                      ++-----------------------++--------------&gt;
+
+This explain how a packet traverse TCP/IP stack in IPsec capable kernel.
+
+FIX ME, please, if there are any errors
+
+Test the new firewall now.
+
+
+Now about IPX. I tried 3 programs for tunneling IPX: tipxd, SIB and ipxtunnel
+
+tipxd didn't send packets.. :(
+SIB and ipxtunnel worked fine :)
+With ipxtunnel there was a little problem. In sources there are an error.
+
+--------------------- in main.c ------------------------
+&lt;       bytes += p.len;
+---
+&gt;       bytes += len;
+--------------------------------------------------------
+
+After this FIX everything goes right...
+
+------------------- /etc/ipxtunnel.conf ----------------
+port    2005
+remote  192.168.101.97    2005
+interface eth1
+--------------- end of /etc/ipxtunnel.conf -------------
+
+I use IPX tunnel between .1.1 and .2.10 so we don't need to encrypt nor
+authenticate encapsulated IPX packets, it is done with IPsec.
+
+If you don't wont to use iproute2 to change source IP you need to use SIB
+(it is able to bind local address) or establish tunnel between .0.1 and
+.0.10 (external IPs, you need to do encryption in the program, but it isn't
+strong).
+
+For now I'm using ipxtunnel.
+
+I think that's all for the moment. If there are any error, please e-mail me: 
+poltorak@df.ru . It would be cool if someone puts the scheme of TCP/IP in
+kernel and firewall example on FreeS/WAN's manual pages.
+
+PoltoS
+</PRE>
+<HR>
+<H1><A name="makecheck">How to configure to use &quot;make check&quot;</A></H1>
+<H2><A NAME="19_1">What is &quot;make check&quot;</A></H2>
+<P> &quot;make check&quot; is a target in the top level makefile. It takes care of
+ running a number of unit and system tests to confirm that FreeSWAN has
+ been compiled correctly, and that no new bugs have been introduced.</P>
+<P> As FreeSWAN contains both kernel and userspace components, doing
+ testing of FreeSWAN requires that the kernel be simulated. This is
+ typically difficult to do as a kernel requires that it be run on bare
+ hardware. A technology has emerged that makes this simpler. This is<A HREF="http://user-mode-linux.sourceforge.net">
+ User Mode Linux</A>.</P>
+<P> User-Mode Linux is a way to build a Linux kernel such that it can
+ run as a process under another Linux (or in the future other) kernel.
+ Presently, this can only be done for 2.4 guest kernels. The host kernel
+ can be 2.2 or 2.4.</P>
+<P> &quot;make check&quot; expects to be able to build User-Mode Linux kernels
+ with FreeSWAN included. To do this it needs to have some files
+ downloaded and extracted prior to running &quot;make check&quot;. This is
+ described in the<A HREF="umltesting.html"> UML testing</A> document.</P>
+<P> After having run the example in the UML testing document and
+ successfully brought up the four machine combination, you are ready to
+ use &quot;make check&quot;</P>
+<H2><A NAME="19_2">Running &quot;make check&quot;</A></H2>
+<P> &quot;make check&quot; works by walking the FreeSWAN source tree invoking the
+ &quot;check&quot; target at each node. At present there are tests defined only
+ for the <CODE>klips</CODE> directory. These tests will use the UML
+ infrastructure to test out pieces of the <CODE>klips</CODE> code.</P>
+<P> The results of the tests can be recorded. If the environment
+ variable <CODE>$REGRESSRESULTS</CODE> is non-null, then the results of
+ each test will be recorded. This can be used as part of a nightly
+ regression testing system, see<A HREF="nightly.html"> Nightly testing</A>
+ for more details.</P>
+<P> &quot;make check&quot; otherwise prints a minimal amount of output for each
+ test, and indicates pass/fail status of each test as they are run.
+ Failed tests do not cause failure of the target in the form of exit
+ codes.</P>
+<H1><A NAME="20">How to write a &quot;make check&quot; test</A></H1>
+<H2><A NAME="20_1">Structure of a test</A></H2>
+<P> Each test consists of a set of directories under <CODE>testing/</CODE>
+. There are directories for <CODE>klips</CODE>, <CODE>pluto</CODE>, <CODE>
+packaging</CODE> and <CODE>libraries</CODE>. Each directory has a list
+ of tests to run is stored in a file called <CODE>TESTLIST</CODE> in
+ that directory. e.g. <CODE>testing/klips/TESTLIST</CODE>.</P>
+<H2 NAME="TESTLIST"><A NAME="20_2">The TESTLIST</A></H2>
+<P> This isn't actually a shell script. It just looks like one. Some
+ tools other than /bin/sh process it. Lines that start with # are
+ comments.</P>
+<PRE>
+# test-kind     directory-containing-test       expectation     [PR#]
+</PRE>
+<P>The first word provides the test type, detailed below.</P>
+<P> The second word is the name of the test to run. This the directory
+ in which the test case is to be found..</P>
+<P>The third word may be one of:</P>
+<DL>
+<DT> blank/good</DT>
+<DD>the test is believed to function, report failure</DD>
+<DT> bad</DT>
+<DD> the test is known to fail, report unexpected success</DD>
+<DT> suspended</DT>
+<DD> the test should not be run</DD>
+</DL>
+<P> The fourth word may be a number, which is a PR# if the test is
+ failing.</P>
+<H2><A NAME="20_3">Test kinds</A></H2>
+ The test types are:
+<DL>
+<DT>skiptest</DT>
+<DD>means run no test.</DD>
+<DT>ctltest</DT>
+<DD>means run a single system without input/output.</DD>
+<DT>klipstest</DT>
+<DD>means run a single system with input/output networks</DD>
+<DT><A HREF="#umlplutotest">umlplutotest</A></DT>
+<DD>means run a pair of systems</DD>
+<DT><A HREF="#umlXhost">umlXhost</A></DT>
+<DD>run an arbitrary number of systems</DD>
+<DT>suntest (TBD)</DT>
+<DD>means run a quad of east/west/sunrise/sunset</DD>
+<DT>roadtest (TBD)</DT>
+<DD>means run a trio of east-sunrise + warrior</DD>
+<DT>extrudedtest (TBD)</DT>
+<DD>means run a quad of east-sunrise + warriorsouth + park</DD>
+<DT>mkinsttest</DT>
+<DD>a test of the &quot;make install&quot; machinery.</DD>
+<DT>kernel_test_patch</DT>
+<DD>a test of the &quot;make kernelpatch&quot; machinery.</DD>
+</DL>
+ Tests marked (TBD) have yet to be fully defined.
+<P> Each test directory has a file in it called <CODE>testparams.sh</CODE>
+. This file sets a number of environment variables to define the
+ parameters of the test.</P>
+<H2><A NAME="20_4">Common parameters</A></H2>
+<DL>
+<DT>TESTNAME</DT>
+<DD>the name of the test (repeated for checking purposes)</DD>
+<DT>TEST_TYPE</DT>
+<DD>the type of the test (repeat of type type above)</DD>
+<DT>TESTHOST</DT>
+<DD>the name of the UML machine to run for the test, typically &quot;east&quot; or
+ &quot;west&quot;</DD>
+<DT>TEST_PURPOSE</DT>
+<DD>The purpose of the test is one of:
+<DL>
+<DT>goal</DT>
+<DD>The goal purpose is where a test is defined for code that is not yet
+ finished. The test indicates when the goals have in fact been reached.</DD>
+<DT>regress</DT>
+<DD>This is a test to determine that a previously existing bug has been
+ repaired. This test will initially be created to reproduce the bug in
+ isolation, and then the bug will be fixed.</DD>
+<DT>exploit</DT>
+<DD>This is a set of packets/programs that causes a vulnerability to be
+ exposed. It is a specific variation of the regress option.</DD>
+</DL>
+</DD>
+<DT>TEST_GOAL_ITEM</DT>
+<DT></DT>
+<DD>in the case of a goal test, this is a reference to the requirements
+ document</DD>
+<DT>TEST_PROB_REPORT</DT>
+<DD>in the case of regression test, this the problem report number from
+ GNATS</DD>
+<DT>TEST_EXPLOIT_URL</DT>
+<DD>in the case of an exploit, this is a URL referencing the paper
+ explaining the origin of the test and the origin of exploit software</DD>
+<DT>REF_CONSOLE_OUTPUT</DT>
+<DD>a file in the test directory that contains the sanitized console
+ output against which to compare the output of the actual test.</DD>
+<DT>REF_CONSOLE_FIXUPS</DT>
+<DD>a list of scripts (found in <CODE>klips/test/fixups</CODE>) to apply
+ to sanitize the console output of the machine under test. These are
+ typically perl, awk or sed scripts that remove things in the kernel
+ output that change each time the test is run and/or compiled.</DD>
+<DT>INIT_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode prior to starting the tests. This file will usually
+ set up any eroute's and SADB entries that are required for the test.</P>
+<P>Lines beginning with # are skipped. Blank lines are skipped.
+ Otherwise, a shell prompted is waited for each time (consisting of <CODE>
+\n#</CODE>) and then the command is sent. Note that the prompt is waited
+ for before the command and not after, so completion of the last command
+ in the script is not required. This is often used to invoke a program
+ to monitor the system, e.g. <CODE>ipsec pf_key</CODE>.</P>
+</DD>
+<DT>RUN_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode, before the packets are sent. On single machine tests,
+ this script doesn't provide any more power than INIT_SCRIPT, but is
+ implemented for consistency's sake.</P>
+</DD>
+<DT>FINAL_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode after the final packet is sent. Similar to
+ INIT_SCRIPT, above. If not specified, then the single command &quot;halt&quot; is
+ sent. If specified, then the script should end with a halt command to
+ nicely shutdown the UML.</P>
+</DD>
+<DT>CONSOLEDIFFDEBUG</DT>
+<DD>If set to &quot;true&quot; then the series of console fixups (see
+ REF_CONSOLE_FIXUPS) will be output after it is constructed. (It should
+ be set to &quot;false&quot;, or unset otherwise)</DD>
+<DT>NETJIGDEBUG</DT>
+<DD>If set to &quot;true&quot; then the series of console fixups (see
+ REF_CONSOLE_FIXUPS) will be output after it is constructed. (It should
+ be set to &quot;false&quot;, or unset otherwise)</DD>
+<DT>NETJIGTESTDEBUG</DT>
+<DD> If set to &quot;netjig&quot;, then the results of talking to the <CODE>
+uml_netjig</CODE> will be printed to stderr during the test. In
+ addition, the jig will be invoked with --debug, which causes it to log
+ its process ID, and wait 60 seconds before continuing. This can be used
+ if you are trying to debug the <CODE>uml_netjig</CODE> program itself.</DD>
+<DT>HOSTTESTDEBUG</DT>
+<DD> If set to &quot;hosttest&quot;, then the results of taling to the consoles of
+ the UMLs will be printed to stderr during the test.</DD>
+<DT>NETJIGWAITUSER</DT>
+<DD> If set to &quot;waituser&quot;, then the scripts will wait forever for user
+ input before they shut the tests down. Use this is if you are debugging
+ through the kernel.</DD>
+<DT>PACKETRATE</DT>
+<DD> A number, in miliseconds (default is 500ms) at which packets will
+ be replayed by the netjig.</DD>
+</DL>
+<H2><A NAME="20_5">KLIPStest paramaters</A></H2>
+<P> The klipstest function starts a program (<CODE>
+testing/utils/uml_netjig/uml_netjig</CODE>) to setup a bunch of I/O
+ sockets (that simulate network interfaces). It then exports the
+ references to these sockets to the environment and invokes (using
+ system()) a given script. It waits for the script to finish.</P>
+
+<!-- <IMG SRC="single_netjig.png" ALT="block diagram of uml_netjig"> -->
+<P> The script invoked (<CODE>testing/utils/host-test.tcl</CODE>) is a
+ TCL<A HREF="http://expect.nist.gov/"> expect</A> script that arranges
+ to start the UML and configure it appropriately for the test. The
+ configuration is done with the script given above for<VAR> INIT_SCRIPT</VAR>
+. The TCL script then forks, leaves the UML in the background and exits.
+ uml_netjig continues. It then starts listening to the simulated network
+ answering ARPs and inserting packets as appropriate.</P>
+<P> The klipstest function invokes <CODE>uml_netjig</CODE> with
+ arguments to capture output from network interface(s) and insert
+ packets as appropriate:</P>
+<DL>
+<DT>PUB_INPUT</DT>
+<DD>a<A HREF="http://www.tcpdump.org/"> pcap</A> file to feed in on the
+ public (encrypted) interface. (typically, eth1)</DD>
+<DT>PRIV_INPUT</DT>
+<DD>a pcap file to feed in on the private (plain-text) interface
+ (typically, eth0).</DD>
+<DT>REF_PUB_OUTPUT</DT>
+<DD>a text file containing tcpdump output. Packets on the public (eth1)
+ interface are captured to a<A HREF="http://www.tcpdump.org/"> pcap</A>
+ file by <CODE>uml_netjig</CODE>. The klipstest function then uses
+ tcpdump on the file to produce text output, which is compared to the
+ file given.</DD>
+<DT>REF_PUB_FILTER</DT>
+<DD>a program that will filter the TCPDUMP output to do further
+ processing. Defaults to &quot;cat&quot;.</DD>
+<DT>REF_PRIV_OUTPUT</DT>
+<DD>a text file containing tcpdump output. Packets on the private (eth0)
+ interface are captured and compared after conversion by tcpdump, as
+ with<VAR> REFPUBOUTPUT</VAR>.</DD>
+<DT>REF_PRIV_FILTER</DT>
+<DD>a program that will filter the TCPDUMP output to do further
+ processing. Defaults to &quot;cat&quot;.</DD>
+<DT>EXITONEMPTY</DT>
+<DD>a flag for <CODE>uml_netjig</CODE>. It should contain
+ &quot;--exitonempty&quot; of uml_netjig should exit when all of the input (<VAR>
+PUBINPUT</VAR>,<VAR>PRIVINPUT</VAR>) packets have been injected.</DD>
+<DT>ARPREPLY</DT>
+<DD>a flag for <CODE>uml_netjig</CODE>. It should contain &quot;--arpreply&quot;
+ if <CODE>uml_netjig</CODE> should reply to ARP requests. One will
+ typically set this to avoid having to fudge the ARP cache manually.</DD>
+<DT>TCPDUMPFLAGS</DT>
+<DD>a set of flags for the tcpdump used when converting captured output.
+ Typical values will include &quot;-n&quot; to turn off DNS, and often &quot;-E&quot; to set
+ the decryption key (tcpdump 3.7.1 and higher only) for ESP packets. The
+ &quot;-t&quot; flag (turn off timestamps) is provided automatically</DD>
+<DT>NETJIG_EXTRA</DT>
+<DD>additional comments to be sent to the netjig. This may arrange to
+ record or create additional networks, or may toggle options.</DD>
+</DL>
+<H2><A NAME="20_6">mkinsttest paramaters</A></H2>
+<P> The basic concept of the <CODE>mkinsttest</CODE> test type is that
+ it performs a &quot;make install&quot; to a temporary $DESTDIR. The resulting
+ tree can then be examined to determine if it was done properly. The
+ files can be uninstalled to determine if the file list was correct, or
+ the contents of files can be examined more precisely.</P>
+<DL>
+<DT>INSTALL_FLAGS</DT>
+<DD>If set, then an install will be done. This provides the set of flags
+ to provide for the install. The target to be used (usually &quot;install&quot;)
+ must be among the flags.</DD>
+<DT>POSTINSTALL_SCRIPT</DT>
+<DD>If set, a script to run after initial &quot;make install&quot;. Two arguments
+ are provided: an absolute path to the root of the FreeSWAN src tree,
+ and an absolute path to the temporary installation area.</DD>
+<DT>INSTALL2_FLAGS</DT>
+<DD>If set, a second install will be done using these flags. Similarly
+ to INSTALL_FLAGS, the target must be among the flags.</DD>
+<DT>UNINSTALL_FLAGS</DT>
+<DD>If set, an uninstall will be done using these flags. Similarly to
+ INSTALL_FLAGS, the target (usually &quot;uninstall&quot;) must be among the
+ flags.</DD>
+<DT>REF_FIND_f_l_OUTPUT</DT>
+<DD>If set, a <CODE>find $ROOT ( -type f -or -type -l )</CODE> will be
+ done to get a list of a real files and symlinks. The resulting file
+ will be compared to the file listed by this option.</DD>
+<DT>REF_FILE_CONTENTS</DT>
+<DD>If set, it should point to a file containing records for the form:
+<PRE>
+  
+<!--VARIABLE-->
+reffile</(null)>   
+<!--VARIABLE-->
+samplefile</(null)>
+</PRE>
+ one record per line. A diff between the provided reference file, and
+ the sample file (located in the temporary installation root) will be
+ done for each record.</DD>
+</DL>
+<H2><A NAME="20_7">rpm_build_install_test paramaters</A></H2>
+<P> The <CODE>rpm_build_install_test</CODE> type is to verify that the
+ proper packing list is produced by &quot;make rpm&quot;, and that the mechanisms
+ for building the kernel modules produce consistent results.</P>
+<DL>
+<DT>RPM_KERNEL_SOURCE</DT>
+<DD>Point to an extracted copy of the RedHat kernel source code.
+ Variables from the environment may be used.</DD>
+<DT>REF_RPM_CONTENTS</DT>
+<DD>This is a file containing one record per line. Each record consists
+ of a RPM name (may contain wildcards) and a filename to compare the
+ contents to. The RPM will be located and a file list will be produced
+ with rpm2cpio.</DD>
+</DL>
+<H2><A NAME="20_8">libtest paramaters</A></H2>
+<P> The libtest test is for testing library routines. The library file
+ is expected to provided an <CODE>#ifdef</CODE> by the name of<VAR>
+ library</VAR>
+<!--CODE_MAIN</CODE-->
+. The libtest type invokes the C compiler to compile this
+ file, links it against <CODE>libfreeswan.a</CODE> (to resolve any other
+ dependancies) and runs the test with the <CODE>-r</CODE> argument to
+ invoke a regression test.</(null)></P>
+<P>The library test case is expected to do a self-test, exiting with
+ status code 0 if everything is okay, and with non-zero otherwise. A
+ core dump (exit code greater than 128) is noted specifically.</P>
+<P> Unlike other tests, there are no subdirectories required, or other
+ parameters to set.</P>
+<H2 NAME="umlplutotest"><A NAME="20_9">umlplutotest paramaters</A></H2>
+<P> The umlplutotest function starts a pair of user mode line processes.
+ This is a 2-host version of umlXhost. The &quot;EAST&quot; and &quot;WEST&quot; slots are
+ defined.</P>
+<H2 NAME="umlXhost"><A NAME="20_10">umlXhost parameters</A></H2>
+<P> The umlXtest function starts an arbitrary number of user mode line
+ processes.</P>
+
+<!-- <IMG SRC="single_netjig.png" ALT="block diagram of uml_netjig"> -->
+<P> The script invoked (<CODE>testing/utils/Xhost-test.tcl</CODE>) is a
+ TCL<A HREF="http://expect.nist.gov/"> expect</A> script that arranges
+ to start each UML and configure it appropriately for the test. It then
+ starts listening (using uml_netjig) to the simulated network answering
+ ARPs and inserting packets as appropriate.</P>
+<P> umlXtest has a series of slots, each of which should be filled by a
+ host. The list of slots is controlled by the variable, XHOST_LIST. This
+ variable should be set to a space seperated list of slots. The former
+ umlplutotest is now implemented as a variation of the umlXhost test,
+ with XHOST_LIST=&quot;EAST WEST&quot;.</P>
+<P> For each host slot that is defined, a series of variables should be
+ filled in, defining what configuration scripts to use for that host.</P>
+<P> The following are used to control the console input and output to
+ the system. Where the string ${host} is present, the host slot should
+ be filled in. I.e. for the two host system with XHOST_LIST=&quot;EAST WEST&quot;,
+ then the variables: EAST_INIT_SCRIPT and WEST_INIT_SCRIPT will exist.</P>
+<DL>
+<DT>${host}HOST</DT>
+<DD>The name of the UML host which will fill this slot</DD>
+<DT>${host}_INIT_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode prior to starting the tests. This file will usually
+ set up any eroute's and SADB entries that are required for the test.
+ Similar to INIT_SCRIPT, above.</P>
+</DD>
+<DT>${host}_RUN_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode, before the packets are sent. This set of commands is
+ run after all of the virtual machines are initialized. I.e. after
+ EAST_INIT_SCRIPT<B> AND</B> WEST_INIT_SCRIPT. This script can therefore
+ do things that require that all machines are properly configured.</P>
+</DD>
+<DT>${host}_RUN2_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode, after the packets are sent. This set of commands is
+ run before any of the virtual machines have been shut down. (I.e.
+ before EAST_FINAL_SCRIPT<B> AND</B> WEST_FINAL_SCRIPT.) This script can
+ therefore catch post-activity status reports.</P>
+</DD>
+<DT>${host}_FINAL_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode after the final packet is sent. Similar to
+ INIT_SCRIPT, above. If not specified, then the single command &quot;halt&quot; is
+ sent. Note that when this script is run, the other virtual machines may
+ already have been killed. If specified, then the script should end with
+ a halt command to nicely shutdown the UML.</P>
+</DD>
+<DT>REF_${host}_CONSOLE_OUTPUT</DT>
+<DD>Similar to REF_CONSOLE_OUTPUT, above.</DD>
+</DL>
+<P>Some additional flags apply to all hosts:</P>
+<DL>
+<DT>REF_CONSOLE_FIXUPS</DT>
+<DD>a list of scripts (found in <CODE>klips/test/fixups</CODE>) to apply
+ to sanitize the console output of the machine under test. These are
+ typically perl, awk or sed scripts that remove things in the kernel
+ output that change each time the test is run and/or compiled.</DD>
+</DL>
+<P> In addition to input to the console, the networks may have input fed
+ to them:</P>
+<DL>
+<DT>EAST_INPUT/WEST_INPUT</DT>
+<DD>a<A HREF="http://www.tcpdump.org/"> pcap</A> file to feed in on the
+ private network side of each network. The &quot;EAST&quot; and &quot;WEST&quot; here refer
+ to the networks, not the hosts.</DD>
+<DT>REF_PUB_FILTER</DT>
+<DD>a program that will filter the TCPDUMP output to do further
+ processing. Defaults to &quot;cat&quot;.</DD>
+<DT>REF_EAST_FILTER/REF_WEST_FILTER</DT>
+<DD>a program that will filter the TCPDUMP output to do further
+ processing. Defaults to &quot;cat&quot;.</DD>
+&lt;
+<DT>TCPDUMPFLAGS</DT>
+<DD>a set of flags for the tcpdump used when converting captured output.
+ Typical values will include &quot;-n&quot; to turn off DNS, and often &quot;-E&quot; to set
+ the decryption key (tcpdump 3.7.1 and higher only) for ESP packets. The
+ &quot;-t&quot; flag (turn off timestamps) is provided automatically</DD>
+<DT>REF_EAST_OUTPUT/REF_WEST_OUTPUT</DT>
+<DD>a text file containing tcpdump output. Packets on the private (eth0)
+ interface are captured and compared after conversion by tcpdump, as
+ with<VAR> REF_PUB_OUTPUT</VAR>.</DD>
+<P> There are two additional environment variables that may be set on
+ the command line:</P>
+<DL>
+<DT> NETJIGVERBOSE=verbose export NETJIGVERBOSE</DT>
+<DD> If set, then the test output will be &quot;chatty&quot;, and let you know
+ what commands it is running, and as packets are sent. Without it set,
+ the output is limited to success/failure messages.</DD>
+<DT> NETJIGTESTDEBUG=netjig export NETJIGTESTDEBUG</DT>
+<DD> This will enable debugging of the communication with uml_netjig,
+ and turn on debugging in this utility. This does not imply
+ NETJIGVERBOSE.</DD>
+</DL>
+<DT> HOSTTESTDEBUG=hosttest export HOSTTESTDEBUG</DT>
+<DD> This will show all interactions with the user-mode-linux consoles</DD>
+</DL>
+<H2 NAME="kernelpatch"><A NAME="20_11">kernel_patch_test paramaters</A></H2>
+<P> The kernel_patch_test function takes some kernel source, copies it
+ with lndir, and then applies the patch as produced by &quot;make
+ kernelpatch&quot;.</P>
+<P> The following are used to control the input and output to the
+ system:</P>
+<DL>
+<DT>KERNEL_NAME</DT>
+<DD>the kernel name, typically something like &quot;linus&quot; or &quot;rh&quot;</DD>
+<DT>KERNEL_VERSION</DT>
+<DD>the kernel version number, as in &quot;2.2&quot; or &quot;2.4&quot;.</DD>
+<DT>KERNEL_${KERNEL_NAME}${KERNEL_VERSION}_SRC</DT>
+<DD>This variable should set in the environment, probably in
+ ~/freeswan-regress-env.sh. Examples of this variables would be
+ KERNEL_LINUS2_0_SRC or KERNEL_RH7_3_SRC. This variable should point to
+ an extracted copy of the kernel source in question.</DD>
+<DT>REF_PATCH_OUTPUT</DT>
+<DD>a copy of the patch output to compare against</DD>
+<DT>KERNEL_PATCH_LEAVE_SOURCE</DT>
+<DD>If set to a non-empty string, then the patched kernel source is not
+ removed at the end of the test. This will typically be set in the
+ environment while debugging.</DD>
+</DL>
+<H2 NAME="modtest"><A NAME="20_12">module_compile paramaters</A></H2>
+<P> The module_compile test attempts to build the KLIPS module against a
+ given set of kernel source. This is also done by the RPM tests, but in
+ a very specific manner.</P>
+<P> There are two variations of this test - one where the kernel either
+ doesn't need to be configured, or is already done, and tests were there
+ is a local configuration file.</P>
+<P> Where the kernel doesn't need to be configured, the kernel source
+ that is found is simply used. It may be a RedHat-style kernel, where
+ one can cause it to configure itself via rhconfig.h-style definitions.
+ Or, it may just be a kernel tree that has been configured.</P>
+<P> If the variable KERNEL_CONFIG_FILE is set, then a new directory is
+ created for the kernel source. It is populated with lndir(1). The
+ referenced file is then copied in as .config, and &quot;make oldconfig&quot; is
+ used to configure the kernel. This resulting kernel is then used as the
+ reference source.</P>
+<P> In all cases, the kernel source is found the same was for the
+ kernelpatch test, i.e. via KERNEL_VERSION/KERNEL_NAME and
+ KERNEL_${KERNEL_NAME}${KERNEL_VERSION}_SRC.</P>
+<P> Once there is kernel source, the module is compiled using the
+ top-level &quot;make module&quot; target.</P>
+<P> The test is considered successful if an executable is found in
+ OUTPUT/module/ipsec.o at the end of the test.</P>
+<DL>
+<DT>KERNEL_NAME</DT>
+<DD>the kernel name, typically something like &quot;linus&quot; or &quot;rh&quot;</DD>
+<DT>KERNEL_VERSION</DT>
+<DD>the kernel version number, as in &quot;2.2&quot; or &quot;2.4&quot;.</DD>
+<DT>KERNEL_${KERNEL_NAME}${KERNEL_VERSION}_SRC</DT>
+<DD>This variable should set in the environment, probably in
+ ~/freeswan-regress-env.sh. Examples of this variables would be
+ KERNEL_LINUS2_0_SRC or KERNEL_RH7_3_SRC. This variable should point to
+ an extracted copy of the kernel source in question.</DD>
+<DT>KERNEL_CONFIG_FILE</DT>
+<DD>The configuration file for the kernel.</DD>
+<DT>KERNEL_PATCH_LEAVE_SOURCE</DT>
+<DD>If set to a non-empty string, then the configured kernel source is
+ not removed at the end of the test. This will typically be set in the
+ environment while debugging.</DD>
+<DT>MODULE_DEF_INCLUDE</DT>
+<DD>The include file that will be used to configure the KLIPS module,
+ and possibly the kernel source.</DD>
+</DL>
+<H1><A NAME="21">Current pitfalls</A></H1>
+<DL>
+<DT> &quot;tcpdump dissector&quot; not available.</DT>
+<DD> This is a non-fatal warning. If uml_netjig is invoked with the -t
+ option, then it will attempt to use tcpdump's dissector to decode each
+ packet that it processes. The dissector is presently not available, so
+ this option it normally turned off at compile time. The dissector
+ library will be released with tcpdump version 4.0.</DD>
+</DL>
+<HR>
+<H1><A name="umltesting">User-Mode-Linux Testing guide</A></H1>
+<P> User mode linux is a way to compile a linux kernel such that it can
+ run as a process in another linux system (potentially as a *BSD or
+ Windows process later). See<A HREF="http://user-mode-linux.sourceforge.net/">
+ http://user-mode-linux.sourceforge.net/</A></P>
+<P> UML is a good platform for testing and experimenting with FreeS/WAN.
+ It allows several network nodes to be simulated on a single machine.
+ Creating, configuring, installing, monitoring, and controling these
+ nodes is generally easier and easier to script with UML than real
+ hardware.</P>
+<P> You'll need about 500Mb of disk space for a full
+ sunrise-east-west-sunset setup. You can possibly get this down by 130Mb
+ if you remove the sunrise/sunset kernel build. If you just want to run,
+ then you can even remove the east/west kernel build.</P>
+<P> Nothing need be done as super user. In a couple of steps, we note
+ where super user is required to install commands in system-wide
+ directories, but ~/bin could be used instead. UML seems to use a
+ system-wide /tmp/uml directory so different users may interfere with
+ one another. Later UMLs use ~/.uml instead, so multiple users running
+ UML tests should not be a problem, but note that a single user running
+ the UML tests will only be able run one set. Further, UMLs sometimes
+ get stuck and hang around. These &quot;zombies&quot; (most will actually be in
+ the &quot;T&quot; state in the process table) will interfere with subsequent
+ tests.</P>
+<H2><A NAME="22_1">Preliminary Notes on BIND</A></H2>
+<P> As of 2003/3/1, the Light-Weight Resolver is used by pluto. This
+ requires that BIND9 be running. It also requires that BIND9 development
+ libraries be present in the build environment. The DNSSEC code is only
+ truly functional in BIND9 snapshots. The library code could be 9.2.2,
+ we believe. We are using BIND9 20021115 snapshot code from<A HREF="ftp://ftp.isc.org/isc/bind9/snapshots">
+ ftp://ftp.isc.org/isc/bind9/snapshots</A>.</P>
+<P> FreeS/WAN may well require a newer BIND than is on your system. Many
+ distributions have moved to BIND9.2.2 recently due to a security
+ advisory. BIND is five components.</P>
+<OL>
+<LI> named</LI>
+<LI> dnssec-*</LI>
+<LI> client side resolver libraries</LI>
+<LI> client side utility libraries I thought there were lib and named
+ parts to dnsssec...</LI>
+<LI> dynamic DNS update utilities</LI>
+</OL>
+<P> The only piece that we need for *building* is #4. That's the only
+ part that has to be on the build host. What is the difference between
+ resolver and util libs? If you want to edit
+ testing/baseconfigs/all/etc/bind, you'll need a snapshot version. The
+ resolver library contains the resolver. FreeS/WAN has its own copy of
+ that in lib/liblwres.</P>
+<H2><A NAME="22_2">Steps to Install UML for FreeS/WAN</A></H2>
+<OL>
+<LI> Get the following files:
+<OL type="a">
+<LI> from<A HREF="http://www.sandelman.ottawa.on.ca/freeswan/uml/">
+ http://www.sandelman.ottawa.on.ca/freeswan/uml/</A>
+ umlfreeroot-15.1.tar.gz (or highest numbered one). This is a debian
+ potato root file system. You can use this even on a Redhat host, as it
+ has the newer GLIBC2.2 libraries as well.
+<!-- If you are using
+  Redhat 7.2 or newer as your development machine, you can create the
+  image from your installation media. See <A HREF="uml-rhroot.html">Building a RedHat root"></A>.
+  A future document will explain how to build this from .DEB files as well.
+-->
+
+<!--
+<LI> umlfreesharemini.tar.gz    (or umlfreeshareall.tar.gz). 
+  If you are a Debian potato user, you don't need it you can use your
+  native /usr/share.
+</UL>
+-->
+</LI>
+<LI> From<A HREF="ftp://ftp.xs4all.nl/pub/crypto/freeswan/">
+ ftp://ftp.xs4all.nl/pub/crypto/freeswan/</A> a snapshot or release
+ (1.92 or better)</LI>
+<LI> From a<A HREF="http://www.kernel.org/mirrors/">
+ http://www.kernel.org mirror</A>, the virgin 2.4.19 kernel. Please
+ realize that we have defaults in our tree for kernel configuration. We
+ try to track the latest UML kernels. If you use a newer kernel, you may
+ have faults in the kernel build process. You can see what the latest
+ that is being regularly tested by visiting<A HREF="http://bugs.freeswan.org:81/regress/HEAD/lastgood/freeswan-regress-env.sh">
+ freeswan-regress-env.sh</A>.</LI>
+<LI>
+<!-- Note: this step is refered to as "step 1d" below. -->
+ Get<A HREF="http://ftp.nl.linux.org/uml/">
+ http://ftp.nl.linux.org/uml/</A> uml-patch-2.4.19-47.bz2 or the one
+ associated with your kernel. As of 2003/03/05, uml-patch-2.4.19-47.bz2
+ works for us.<STRONG> More recent versions of the patch have not been
+ tested by us.</STRONG></LI>
+<LI> You'll probably want to visit<A HREF="http://user-mode-linux.sourceforge.net">
+ http://user-mode-linux.sourceforge.net</A> and get the UML utilities.
+ These are not needed for the build or interactive use (but
+ recommended). They are necessary for the regression testing procedures
+ used by &quot;make check&quot;. We currently use uml_utilities_20020212.tar.bz2.</LI>
+<LI> You need tcpdump version 3.7.1 or better. This is newer than the
+ version included in most LINUX distributions. You can check the version
+ of an installed tcpdump with the --version flag. If you need a newer
+ tcpdump fetch both tcpdump and libpcap source tar files from<A HREF="http://www.tcpdump.org/">
+ http://www.tcpdump.org/</A> or a mirror.</LI>
+</OL>
+</LI>
+<LI> Pick a suitable place, and extract the following files:
+<OL type="a">
+<LI>
+<!-- Note: this step is refered to as "step 2a" later. -->
+ 2.4.19 kernel. For instance:
+<PRE>
+ <CODE>           cd /c2/kernel
+           tar xzvf ../download/pub/linux/kernel/v2.4/linux-2.4.19.tar.gz
+</CODE>
+</PRE>
+</LI>
+<LI> extract the umlfreeroot file
+<!-- (unless you <A HREF="uml-rhroot.html">built your own from RPMs</A>) -->
+
+<PRE>
+ <CODE>           mkdir -p /c2/user-mode-linux/basic-root
+           cd /c2/user-mode-linux/basic-root
+           tar xzvf ../download/umlfreeroot-15.1.tar.gz
+</CODE>
+</PRE>
+</LI>
+<LI> FreeSWAN itself (or checkout &quot;all&quot; from CVS)
+<PRE>
+ <CODE>           mkdir -p /c2/freeswan/sandbox
+           cd /c2/freeswan/sandbox
+           tar xzvf ../download/snapshot.tar.gz
+</CODE>
+</PRE>
+</LI>
+</OL>
+</LI>
+<LI> If you need to build a newer tcpdump:
+<UL>
+<LI> Make sure you have OpenSSL installed -- it is needed for
+ cryptographic routines.</LI>
+<LI> Unpack libpcap and tcpdump source in parallel directories (the
+ tcpdump build procedures look for libpcap next door).</LI>
+<LI> Change directory into the libpcap source directory and then build
+ the library:
+<PRE>
+ <CODE>	./configure
+	make
+</CODE>
+</PRE>
+</LI>
+<LI> Change into the tcpdump source directory, build tcpdump, and
+ install it.
+<PRE>
+ <CODE>	./configure
+	make
+	# Need to be superuser to install in system directories.
+	# Installing in ~/bin would be an alternative.
+	su -c &quot;make install&quot;
+</CODE>
+</PRE>
+</LI>
+</UL>
+</LI>
+<LI> If you need the uml utilities, unpack them somewhere then build and
+ install them:
+<PRE>
+ <CODE>	cd tools
+	make all
+	# Need to be superuser to install in system directories.
+	# Installing in ~/bin would be an alternative.
+	su -c &quot;make install BIN_DIR=/usr/local/bin&quot;
+</CODE>
+</PRE>
+</LI>
+<LI> set up the configuration file
+<UL>
+<LI> <CODE>cd /c2/freeswan/sandbox/freeswan-1.97/testing/utils</CODE></LI>
+<LI> copy umlsetup-sample.sh to ../../umlsetup.sh: <CODE> cp
+ umlsetup-sample.sh ../../umlsetup.sh</CODE></LI>
+<LI> open up ../../umlsetup.sh in your favorite editor.</LI>
+<LI> change POOLSPACE= to point to the place with at least 500Mb of
+ disk. Best if it is on the same partition as the &quot;umlfreeroot&quot;
+ extraction, as it will attempt to use hard links if possible to save
+ disk space.</LI>
+<LI> Set TESTINGROOT if you intend to run the script outside of the
+ sandbox/snapshot/release directory. Otherwise, it will configure
+ itself.</LI>
+<LI> KERNPOOL should point to the directory with your 2.4.19 kernel
+ tree. This tree should be unconfigured! This is the directory you used
+ in step 2a.</LI>
+<LI> UMLPATCH should point at the bz2 file you downloaded at 1d. If
+ using a kernel that already includes the patch, set this to /dev/null.</LI>
+<LI> FREESWANDIR should point at the directory where you unpacked the
+ snapshot/release. Include the &quot;freeswan-snap2001sep16b&quot; or whatever in
+ it. If you are running from CVS, then you point at the directory where
+ top, klips, etc. are. The script will fix up the directory so that it
+ can be used.</LI>
+<LI> BASICROOT should be set to the directory used in 2b, or to the
+ directory that you created with RPMs.</LI>
+<LI> SHAREDIR should be set to the directory used in 2c, to /usr/share
+ for Debian potato users, or to $BASICROOT/usr/share.</LI>
+</UL>
+</LI>
+<LI>
+<PRE> <CODE>cd $TESTINGROOT/utils
+sh make-uml.sh
+</CODE></PRE>
+ It will grind for awhile. If there are errors it will bail. If so, run
+ it under &quot;script&quot; and send the output to bugs@lists.freeswan.org.</LI>
+<LI> You will have a bunch of stuff under $POOLSPACE. Open four xterms:
+<PRE> <CODE>    for i in sunrise sunset east west
+    do
+        xterm -name $i -title $i -e $POOLSPACE/$i/start.sh     done
+</CODE></PRE>
+</LI>
+<LI> Login as root. Password is &quot;root&quot; (Note, these virtual machines are
+ networked together, but are not configured to talk to the rest of the
+ world.)</LI>
+<LI> verify that pluto started on east/west, run &quot;ipsec look&quot;</LI>
+<LI> login to sunrise. run &quot;ping sunset&quot;</LI>
+<LI> login to west. run &quot;tcpdump -p -i eth1 -n&quot; (tcpdump must be version
+ 3.7.1 or newer)</LI>
+<LI> Closing a console xterm will shut down that UML.</LI>
+<LI> You can &quot;make check&quot;, if you want to. It is run from
+ /c2/freeswan/sandbox/freeswan-1.97.</LI>
+</OL>
+<H1><A NAME="23">Debugging the kernel with GDB</A></H1>
+<P> With User-Mode-Linux, you can debug the kernel using GDB. See
+<!--HREF="http://user-mode-linux.sourceforge.net/debugging.html"-->
+
+ http://user-mode-linux.sourceforge.net/debugging.html.</(null)></P>
+<P> Typically, one will want to address a test case for a failing
+ situation. Running GDB from Emacs, or from other front ends is
+ possible. First start GDB.</P>
+<P> Tell it to open the UMLPOOL/swan/linux program.</P>
+<P> Note the PID of GDB:</P>
+<PRE>
+marajade-[projects/freeswan/mgmt/planning] mcr 1029 %ps ax | grep gdb
+ 1659 pts/9    SN     0:00 /usr/bin/gdb -fullname -cd /mara4/freeswan/kernpatch/UMLPOOL/swan/ linux
+</PRE>
+<P> Set the following in the environment:</P>
+<PRE>
+UML_east_OPT=&quot;debug gdb-pid=1659&quot;
+</PRE>
+<P> Then start the user-mode-linux in the test scheme you wish:</P>
+<PRE>
+marajade-[kernpatch/testing/klips/east-icmp-02] mcr 1220 %../../utils/runme.sh
+</PRE>
+ The user-mode-linux will stop on boot, giving you a chance to attach to
+ the process:
+<PRE>
+(gdb) file linux
+Reading symbols from linux...done.
+(gdb) attach 1
+Attaching to program: /mara4/freeswan/kernpatch/UMLPOOL/swan/linux, process 1
+0xa0118bc1 in kill () at hostfs_kern.c:770
+</PRE>
+<P> At this point, break points should be created as appropriate.</P>
+<H2><A NAME="23_1">Other notes about debugging</A></H2>
+<P> If you are running a standard test, after all the packets are sent,
+ the UML will be shutdown. This can cause problems, because the UML may
+ get terminated while you are debugging.</P>
+<P> The environment variable <CODE>NETJIGWAITUSER</CODE> can be set to
+ &quot;waituser&quot;. If so, then the testing system will prompt before exiting
+ the test.</P>
+<H1><A NAME="24">User-Mode-Linux mysteries</A></H1>
+<UL>
+<LI> running more than one UML of the same name (e.g. &quot;west&quot;) can cause
+ problems.</LI>
+<LI> running more than one UML from the same root file system is not a
+ good idea.</LI>
+<LI> all this means that running &quot;make check&quot; twice on the same machine
+ is probably not a good idea.</LI>
+<LI> occationally, UMLs will get stuck. This can happen like:
+<!--BLOCK-->
+ 15134 ? T
+ 0:00 /spare/hugh/uml/uml2.4.18-sept5/umlbuild/east/linux (east)
+ [/bin/sh] 15138 ? T 0:00
+ /spare/hugh/uml/uml2.4.18-sept5/umlbuild/east/linux (east) [halt]</(null)>
+ these will need to be killed. Note that they are in &quot;T&quot;racing mode.</LI>
+<LI> UMLs can also hang, and will report &quot;Tracing myself and I can't get
+ out&quot;. This is a bug in UML. There are ways to find out what is going on
+ and report this to the UML people, but we don't know the magic right
+ now.</LI>
+</UL>
+<H1><A NAME="25">Getting more info from uml_netjig</A></H1>
+<P> uml_netjig can be compiled with a built-in tcpdump. This uses
+ not-yet-released code from<A HREF="http://www.tcpdump.org/">
+ www.tcpdump.org</A>. Please see the instructions in <CODE>
+testing/utils/uml_netjig/Makefile</CODE>.</P>
+<HR>
+<H1><A name="politics">History and politics of cryptography</A></H1>
+<P>Cryptography has a long and interesting history, and has been the
+ subject of considerable political controversy.</P>
+<H2><A name="intro.politics">Introduction</A></H2>
+<H3><A NAME="26_1_1">History</A></H3>
+<P>The classic book on the history of cryptography is David Kahn's<A href="#Kahn">
+ The Codebreakers</A>. It traces codes and codebreaking from ancient
+ Egypt to the 20th century.</P>
+<P>Diffie and Landau<A href="#diffie"> Privacy on the Line: The Politics
+ of Wiretapping and Encryption</A> covers the history from the First
+ World War to the 1990s, with an emphasis on the US.</P>
+<H4><A NAME="26_1_1_1">World War II</A></H4>
+<P>During the Second World War, the British &quot;Ultra&quot; project achieved one
+ of the greatest intelligence triumphs in the history of warfare,
+ breaking many Axis codes. One major target was the Enigma cipher
+ machine, a German device whose users were convinced it was unbreakable.
+ The American &quot;Magic&quot; project had some similar triumphs against Japanese
+ codes.</P>
+<P>There are many books on this period. See our bibliography for
+ several. Two I particularly like are:</P>
+<UL>
+<LI>Andrew Hodges has done a superb<A href="http://www.turing.org.uk/book/">
+ biography</A> of Alan Turing, a key player among the Ultra
+ codebreakers. Turing was also an important computer pioneer. The terms<A
+href="http://www.abelard.org/turpap/turpap.htm"> Turing test</A> and<A href="http://plato.stanford.edu/entries/turing-machine/">
+ Turing machine</A> are named for him, as is the<A href="http://www.acm.org">
+ ACM</A>'s highest technical<A href="http://www.acm.org/awards/taward.html">
+ award</A>.</LI>
+<LI>Neal Stephenson's<A href="#neal"> Cryptonomicon</A> is a novel with
+ cryptography central to the plot. Parts of it take place during WW II,
+ other parts today.</LI>
+</UL>
+<P>Bletchley Park, where much of the Ultra work was done, now has a
+ museum and a<A href="http://www.bletchleypark.org.uk/"> web site</A>.</P>
+<P>The Ultra work introduced three major innovations.</P>
+<UL>
+<LI>The first break of Enigma was achieved by Polish Intelligence in
+ 1931. Until then most code-breakers had been linguists, but a different
+ approach was needed to break machine ciphers. Polish Intelligence
+ recruited bright young mathematicians to crack the &quot;unbreakable&quot;
+ Enigma. When war came in 1939, the Poles told their allies about this,
+ putting Britain on the road to Ultra. The British also adopted a
+ mathematical approach.</LI>
+<LI>Machines were extensively used in the attacks. First the Polish
+ &quot;Bombe&quot; for attacking Enigma, then British versions of it, then
+ machines such as Collosus for attacking other codes. By the end of the
+ war, some of these machines were beginning to closely resemble digital
+ computers. After the war, a team at Manchester University, several old
+ Ultra hands included, built one of the world's first actual
+ general-purpose digital computers.</LI>
+<LI>Ultra made codebreaking a large-scale enterprise, producing
+ intelligence on an industrial scale. This was not a &quot;black chamber&quot;,
+ not a hidden room in some obscure government building with a small crew
+ of code-breakers. The whole operation -- from wholesale interception of
+ enemy communications by stations around the world, through large-scale
+ code-breaking and analysis of the decrypted material (with an enormous
+ set of files for cross-referencing), to delivery of intelligence to
+ field commanders -- was huge, and very carefully managed.</LI>
+</UL>
+<P>So by the end of the war, Allied code-breakers were expert at
+ large-scale mechanised code-breaking. The payoffs were enormous.</P>
+<H4><A name="postwar">Postwar and Cold War</A></H4>
+<P>The wartime innovations were enthusiastically adopted by post-war and
+ Cold War signals intelligence agencies. Presumably many nations now
+ have some agency capable of sophisticated attacks on communications
+ security, and quite a few engage in such activity on a large scale.</P>
+<P>America's<A href="#NSA"> NSA</A>, for example, is said to be both the
+ world's largest employer of mathematicians and the world's largest
+ purchaser of computer equipment. Such claims may be somewhat
+ exaggerated, but beyond doubt the NSA -- and similar agencies in other
+ countries -- have some excellent mathematicians, lots of powerful
+ computers, sophisticated software, and the organisation and funding to
+ apply them on a large scale. Details of the NSA budget are secret, but
+ there are some published<A href="http://www.fas.org/irp/nsa/nsabudget.html">
+ estimates</A>.</P>
+<P>Changes in the world's communications systems since WW II have
+ provided these agencies with new targets. Cracking the codes used on an
+ enemy's military or diplomatic communications has been common practice
+ for centuries. Extensive use of radio in war made large-scale attacks
+ such as Ultra possible. Modern communications make it possible to go
+ far beyond that. Consider listening in on cell phones, or intercepting
+ electronic mail, or tapping into the huge volumes of data on new media
+ such as fiber optics or satellite links. None of these targets existed
+ in 1950. All of them can be attacked today, and almost certainly are
+ being attacked.</P>
+<P>The Ultra story was not made public until the 1970s. Much of the
+ recent history of codes and code-breaking has not been made public, and
+ some of it may never be. Two important books are:</P>
+<UL>
+<LI>Bamford's<A href="#puzzle"> The Puzzle Palace</A>, a history of the
+ NSA</LI>
+<LI>Hager's<A href="http://www.fas.org/irp/eprint/sp/index.html"> Secret
+ Power</A>, about the<A href="http://sg.yahoo.com/government/intelligence/echelon_network/">
+ Echelon</A> system -- the US, UK, Canada, Australia and New Zealand
+ co-operating to monitor much of the world's communications.</LI>
+</UL>
+<P>Note that these books cover only part of what is actually going on,
+ and then only the activities of nations open and democratic enough that
+ (some of) what they are doing can be discovered. A full picture,
+ including:</P>
+<UL>
+<LI>actions of the English-speaking democracies not covered in those
+ books</LI>
+<LI>actions of other more-or-less sane governments</LI>
+<LI>the activities of various more-or-less insane governments</LI>
+<LI>possibilities for unauthorized action by government employees</LI>
+<LI>possible actions by large non-government organisations:
+ corporations, criminals, or conspiracies</LI>
+</UL>
+<P>might be really frightening.</P>
+<H4><A name="recent">Recent history -- the crypto wars</A></H4>
+<P>Until quite recently, cryptography was primarily a concern of
+ governments, especially of the military, of spies, and of diplomats.
+ Much of it was extremely secret.</P>
+<P>In recent years, that has changed a great deal. With computers and
+ networking becoming ubiquitous, cryptography is now important to almost
+ everyone. Among the developments since the 1970s:</P>
+<UL>
+<LI>The US gov't established the Data Encryption Standard,<A href="#DES">
+ DES</A>, a<A href="#block"> block cipher</A> for cryptographic
+ protection of unclassfied documents.</LI>
+<LI>DES also became widely used in industry, especially regulated
+ industries such as banking.</LI>
+<LI>Other nations produced their own standards, such as<A href="glossary.html#GOST">
+ GOST</A> in the Soviet Union.</LI>
+<LI><A href="#public">Public key</A> cryptography was invented by Diffie
+ and Hellman.</LI>
+<LI>Academic conferences such as<A href="http://www-cse.ucsd.edu/users/mihir/crypto2k.html">
+ Crypto</A> and<A href="http://www.esat.kuleuven.ac.be/cosic/eurocrypt2000/">
+ Eurocrypt</A> began.</LI>
+<LI>Several companies began offerring cryptographic products:<A href="#RSAco">
+ RSA</A>,<A href="#PGPI"> PGP</A>, the many vendors with<A href="#PKI">
+ PKI</A> products, ...</LI>
+<LI>Cryptography appeared in other products: operating systems, word
+ processors, ...</LI>
+<LI>Network protocols based on crypto were developed:<A href="#ssh"> SSH</A>
+,<A href="#SSL"> SSL</A>,<A href="#IPSEC"> IPsec</A>, ...</LI>
+<LI>Crytography came into widespread use to secure bank cards,
+ terminals, ...</LI>
+<LI>The US government replaced<A href="#DES"> DES</A> with the much
+ stronger Advanced Encryption Standard,<A href="#AES"> AES</A></LI>
+</UL>
+<P>This has led to a complex ongoing battle between various mainly
+ government groups wanting to control the spread of crypto and various
+ others, notably the computer industry and the<A href="http://online.offshore.com.ai/security/">
+ cypherpunk</A> crypto advocates, wanting to encourage widespread use.</P>
+<P>Steven Levy has written a fine history of much of this, called<A href="#crypto">
+ Crypto: How the Code rebels Beat the Government -- Saving Privacy in
+ the Digital Age</A>.</P>
+<P>The FreeS/WAN project is to a large extent an outgrowth of cypherpunk
+ ideas. Our reasons for doing the project can be seen in these quotes
+ from the<A href="http://www.eff.org/pub/Privacy/Crypto_misc/cypherpunk.manifesto">
+ Cypherpunk Manifesto</A>:</P>
+<BLOCKQUOTE> Privacy is necessary for an open society in the electronic
+ age. ...
+<P>We cannot expect governments, corporations, or other large, faceless
+ organizations to grant us privacy out of their beneficence. It is to
+ their advantage to speak of us, and we should expect that they will
+ speak. ...</P>
+<P>We must defend our own privacy if we expect to have any. ...</P>
+<P>Cypherpunks write code. We know that someone has to write software to
+ defend privacy, and since we can't get privacy unless we all do, we're
+ going to write it. We publish our code so that our fellow Cypherpunks
+ may practice and play with it. Our code is free for all to use,
+ worldwide. We don't much care if you don't approve of the software we
+ write. We know that software can't be destroyed and that a widely
+ dispersed system can't be shut down.</P>
+<P>Cypherpunks deplore regulations on cryptography, for encryption is
+ fundamentally a private act. ...</P>
+<P>For privacy to be widespread it must be part of a social contract.
+ People must come and together deploy these systems for the common good.
+ ...</P>
+</BLOCKQUOTE>
+<P>To quote project leader John Gilmore:</P>
+<BLOCKQUOTE> We are literally in a race between our ability to build and
+ deploy technology, and their ability to build and deploy laws and
+ treaties. Neither side is likely to back down or wise up until it has
+ definitively lost the race.</BLOCKQUOTE>
+<P>If FreeS/WAN reaches its goal of making<A href="#opp.intro">
+ opportunistic encryption</A> widespread so that secure communication
+ can become the default for a large part of the net, we will have struck
+ a major blow.</P>
+<H3><A name="intro.poli">Politics</A></H3>
+<P>The political problem is that nearly all governments want to monitor
+ their enemies' communications, and some want to monitor their citizens.
+ They may be very interested in protecting some of their own
+ communications, and often some types of business communication, but not
+ in having everyone able to communicate securely. They therefore attempt
+ to restrict availability of strong cryptography as much as possible.</P>
+<P>Things various governments have tried or are trying include:</P>
+<UL>
+<LI>Echelon, a monitor-the-world project of the US, UK, NZ, Australian
+ and Canadian<A href="#SIGINT"> signals intelligence</A> agencies. See
+ this<A href="http://sg.yahoo.com/government/intelligence/echelon_network/">
+ collection</A> of links and this<A href="http://www.zdnet.com/zdnn/stories/news/0,4586,2640682,00.html">
+ story</A> on the French Parliament's reaction.</LI>
+<LI>Others governments may well have their own Echelon-like projects. To
+ quote the Dutch Minister of Defense, as reported in a German<A href="http://www.heise.de/tp/english/inhalt/te/4729/1.html">
+ magazine</A>:<BLOCKQUOTE> The government believes not only the
+ governments associated with Echelon are able to intercept communication
+ systems, but that it is an activity of the investigative authorities
+ and intelligence services of many countries with governments of
+ different political signature.</BLOCKQUOTE> Even if they have nothing
+ on the scale of Echelon, most intelligence agencies and police forces
+ certainly have some interception capability.</LI>
+<LI><A href="#NSA">NSA</A> tapping of submarine communication cables,
+ described in<A href="http://www.zdnet.com/zdnn/stories/news/0,4586,2764372,00.html">
+ this article</A></LI>
+<LI>A proposal for international co-operation on<A href="http://www.heise.de/tp/english/special/enfo/4306/1.html">
+ Internet surveillance</A>.</LI>
+<LI>Alleged<A href="http://cryptome.org/nsa-sabotage.htm"> sabotage</A>
+ of security products by the<A href="#NSA"> NSA</A> (the US signals
+ intelligence agency).</LI>
+<LI>The German armed forces and some government departments will stop
+ using American software for fear of NSA &quot;back doors&quot;, according to this<A
+href="http://www.theregister.co.uk/content/4/17679.html"> news story</A>
+.</LI>
+<LI>The British Regulation of Investigatory Powers bill. See this<A href="http://www.fipr.org/rip/index.html">
+ web page.</A> and perhaps this<A href="http://ars.userfriendly.org/cartoons/?id=20000806&amp;mode=classic">
+ cartoon</A>.</LI>
+<LI>A Russian<A href="http://www.eff.org/pub/Privacy/Foreign_and_local/Russia/russian_crypto_ban_english.edict">
+ ban</A> on cryptography</LI>
+<LI>Chinese<A href="http://www.eff.org/pub/Misc/Publications/Declan_McCullagh/www/global/china">
+ controls</A> on net use.</LI>
+<LI>The FBI's carnivore system for covert searches of email. See this<A href="http://www.zdnet.com/zdnn/stories/news/0,4586,2601502,00.html">
+ news coverage</A> and this<A href="http://www.crypto.com/papers/carnivore-risks.html">
+ risk assessment</A>. The government had an external review of some
+ aspects of this system done. See this<A href="http://www.crypto.com/papers/carnivore_report_comments.html">
+ analysis</A> of that review. Possible defenses against Carnivore
+ include:
+<UL>
+<LI><A href="#PGP">PGP</A> for end-to-end mail encryption</LI>
+<LI><A href="http://www.home.aone.net.au/qualcomm/">secure sendmail</A>
+ for server-to-server encryption</LI>
+<LI>IPsec encryption on the underlying IP network</LI>
+</UL>
+</LI>
+<LI>export laws restricting strong cryptography as a munition. See<A href="#exlaw">
+ discussion</A> below.</LI>
+<LI>various attempts to convince people that fundamentally flawed
+ cryptography, such as encryption with a<A href="#escrow"> back door</A>
+ for government access to data or with<A href="#shortkeys"> inadequate
+ key lengths</A>, was adequate for their needs.</LI>
+</UL>
+<P>Of course governments are by no means the only threat to privacy and
+ security on the net. Other threats include:</P>
+<UL>
+<LI>industrial espionage, as for example in this<A href="http://www.zdnet.com/zdnn/stories/news/0,4586,2626931,00.html">
+ news story</A></LI>
+<LI>attacks by organised criminals, as in this<A href="http://www.sans.org/newlook/alerts/NTE-bank.htm">
+ large-scale attack</A></LI>
+<LI>collection of personal data by various companies.
+<UL>
+<LI>for example, consider the various corporate winners of Privacy
+ International's<A href="http://www.privacyinternational.org/bigbrother/">
+ Big Brother Awards</A>.</LI>
+<LI><A href="http://www.zeroknowledge.com">Zero Knowledge</A> sell tools
+ to defend against this</LI>
+</UL>
+</LI>
+<LI>individuals may also be a threat in a variety of ways and for a
+ variety of reasons</LI>
+<LI>in particular, an individual with access to government or industry
+ data collections could do considerable damage using that data in
+ unauthorized ways.</LI>
+</UL>
+<P>One<A href="http://www.zdnet.com/zdnn/stories/news/0,4586,2640674,00.html">
+ study</A> enumerates threats and possible responses for small and
+ medium businesses. VPNs are a key part of the suggested strategy.</P>
+<P>We consider privacy a human right. See the UN's<A href="http://www.un.org/Overview/rights.html">
+ Universal Declaration of Human Rights</A>, article twelve:</P>
+<BLOCKQUOTE> No one shall be subjected to arbitrary interference with
+ his privacy, family, home or correspondence, nor to attacks upon his
+ honor and reputation. Everyone has the right to the protection of the
+ law against such interference or attacks.</BLOCKQUOTE>
+<P>Our objective is to help make privacy possible on the Internet using
+ cryptography strong enough not even those well-funded government
+ agencies are likely to break it. If we can do that, the chances of
+ anyone else breaking it are negliible.</P>
+<H3><A NAME="26_1_3">Links</A></H3>
+<P>Many groups are working in different ways to defend privacy on the
+ net and elsewhere. Please consider contributing to one or more of these
+ groups:</P>
+<UL>
+<LI>the EFF's<A href="http://www.eff.org/crypto/"> Privacy Now!</A>
+ campaign</LI>
+<LI>the<A href="http://www.gilc.org"> Global Internet Liberty Campaign</A>
+</LI>
+<LI><A href="http://www.cpsr.org/program/privacy/privacy.html">Computer
+ Professionals for Social Responsibility</A></LI>
+</UL>
+<P>For more on these issues see:</P>
+<UL>
+<LI>Steven Levy (Newsweek's chief technology writer and author of the
+ classic &quot;Hackers&quot;) new book<A href="#crypto"> Crypto: How the Code
+ Rebels Beat the Government--Saving Privacy in the Digital Age</A></LI>
+<LI>Simson Garfinkel (Boston Globe columnist and author of books on<A href="#PGP">
+ PGP</A> and<A href="#practical"> Unix Security</A>) book<A href="#Garfinkel">
+ Database Nation: the death of privacy in the 21st century</A></LI>
+</UL>
+<P>There are several collections of<A href="#quotes"> crypto quotes</A>
+ on the net.</P>
+<P>See also the<A href="biblio.html"> bibliography</A> and our list of<A href="#policy">
+ web references</A> on cryptography law and policy.</P>
+<H3><A NAME="26_1_4">Outline of this section</A></H3>
+<P>The remainder of this section includes two pieces of writing by our
+ project leader</P>
+<UL>
+<LI>his<A href="#gilmore"> rationale</A> for starting this</LI>
+<LI>another<A href="#policestate"> discussion</A> of project goals</LI>
+</UL>
+<P>and discussions of:</P>
+<UL>
+<LI><A href="#desnotsecure">why we do not use DES</A></LI>
+<LI><A href="#exlaw">cryptography export laws</A></LI>
+<LI>why<A href="#escrow"> government access to keys</A> is not a good
+ idea</LI>
+<LI>the myth that<A href="#shortkeys"> short keys</A> are adequate for
+ some security requirements</LI>
+</UL>
+<P>and a section on<A href="#press"> press coverage of FreeS/WAN</A>.</P>
+<H2><A name="leader">From our project leader</A></H2>
+<P>FreeS/WAN project founder John Gilmore wrote a web page about why we
+ are doing this. The version below is slightly edited, to fit this
+ format and to update some links. For a version without these edits, see
+ his<A href="http://www.toad.com/gnu/"> home page</A>.</P>
+<CENTER>
+<H3><A name="gilmore">Swan: Securing the Internet against Wiretapping</A>
+</H3>
+</CENTER>
+<P>My project for 1996 was to<B> secure 5% of the Internet traffic
+ against passive wiretapping</B>. It didn't happen in 1996, so I'm still
+ working on it in 1997, 1998, and 1999! If we get 5% in 1999 or 2000, we
+ can secure 20% the next year, against both active and passive attacks;
+ and 80% the following year. Soon the whole Internet will be private and
+ secure. The project is called S/WAN or S/Wan or Swan for Secure Wide
+ Area Network; since it's free software, we call it FreeSwan to
+ distinguish it from various commercial implementations.<A href="http://www.rsa.com/rsa/SWAN/">
+ RSA</A> came up with the term &quot;S/WAN&quot;. Our main web site is at<A href="http://www.freeswan.org/">
+ http://www.freeswan.org/</A>. Want to help?</P>
+<P>The idea is to deploy PC-based boxes that will sit between your local
+ area network and the Internet (near your firewall or router) which
+ opportunistically encrypt your Internet packets. Whenever you talk to a
+ machine (like a Web site) that doesn't support encryption, your traffic
+ goes out &quot;in the clear&quot; as usual. Whenever you connect to a machine
+ that does support this kind of encryption, this box automatically
+ encrypts all your packets, and decrypts the ones that come in. In
+ effect, each packet gets put into an &quot;envelope&quot; on one side of the net,
+ and removed from the envelope when it reaches its destination. This
+ works for all kinds of Internet traffic, including Web access, Telnet,
+ FTP, email, IRC, Usenet, etc.</P>
+<P>The encryption boxes are standard PC's that use freely available
+ Linux software that you can download over the Internet or install from
+ a cheap CDROM.</P>
+<P>This wasn't just my idea; lots of people have been working on it for
+ years. The encryption protocols for these boxes are called<A href="#IPSEC">
+ IPSEC (IP Security)</A>. They have been developed by the<A href="http://www.ietf.cnri.reston.va.us/html.charters/ipsec-charter.html">
+ IP Security Working Group</A> of the<A href="http://www.ietf.org/">
+ Internet Engineering Task Force</A>, and will be a standard part of the
+ next major version of the Internet protocols (<A href="http://playground.sun.com/pub/ipng/html/ipng-main.html">
+IPv6</A>). For today's (IP version 4) Internet, they are an option.</P>
+<P>The<A href="http://www.iab.org/iab"> Internet Architecture Board</A>
+ and<A href="http://www.ietf.org/"> Internet Engineering Steering Group</A>
+ have taken a<A href="iab-iesg.stmt"> strong stand</A> that the Internet
+ should use powerful encryption to provide security and privacy. I think
+ these protocols are the best chance to do that, because they can be
+ deployed very easily, without changing your hardware or software or
+ retraining your users. They offer the best security we know how to
+ build, using the Triple-DES, RSA, and Diffie-Hellman algorithms.</P>
+<P>This &quot;opportunistic encryption box&quot; offers the &quot;fax effect&quot;. As each
+ person installs one for their own use, it becomes more valuable for
+ their neighbors to install one too, because there's one more person to
+ use it with. The software automatically notices each newly installed
+ box, and doesn't require a network administrator to reconfigure it.
+ Instead of &quot;virtual private networks&quot; we have a &quot;REAL private network&quot;;
+ we add privacy to the real network instead of layering a
+ manually-maintained virtual network on top of an insecure Internet.</P>
+<H4><A NAME="26_2_1_1">Deployment of IPSEC</A></H4>
+<P>The US government would like to control the deployment of IP Security
+ with its<A href="#exlaw"> crypto export laws</A>. This isn't a problem
+ for my effort, because the cryptographic work is happening outside the
+ United States. A foreign philanthropist, and others, have donated the
+ resources required to add these protocols to the Linux operating
+ system.<A href="http://www.linux.org/"> Linux</A> is a complete, freely
+ available operating system for IBM PC's and several kinds of
+ workstation, which is compatible with Unix. It was written by Linus
+ Torvalds, and is still maintained by a talented team of expert
+ programmers working all over the world and coordinating over the
+ Internet. Linux is distributed under the<A href="#GPL"> GNU Public
+ License</A>, which gives everyone the right to copy it, improve it,
+ give it to their friends, sell it commercially, or do just about
+ anything else with it, without paying anyone for the privilege.</P>
+<P>Organizations that want to secure their network will be able to put
+ two Ethernet cards into an IBM PC, install Linux on it from a $30 CDROM
+ or by downloading it over the net, and plug it in between their
+ Ethernet and their Internet link or firewall. That's all they'll have
+ to do to encrypt their Internet traffic everywhere outside their own
+ local area network.</P>
+<P>Travelers will be able to run Linux on their laptops, to secure their
+ connection back to their home network (and to everywhere else that they
+ connect to, such as customer sites). Anyone who runs Linux on a
+ standalone PC will also be able to secure their network connections,
+ without changing their application software or how they operate their
+ computer from day to day.</P>
+<P>There will also be numerous commercially available firewalls that use
+ this technology.<A href="http://www.rsa.com/"> RSA Data Security</A> is
+ coordinating the<A href="http://www.rsa.com/rsa/SWAN"> S/Wan (Secure
+ Wide Area Network)</A> project among more than a dozen vendors who use
+ these protocols. There's a<A href="http://www.rsa.com/rsa/SWAN/swan_test.htm">
+ compatability chart</A> that shows which vendors have tested their
+ boxes against which other vendors to guarantee interoperatility.</P>
+<P>Eventually it will also move into the operating systems and
+ networking protocol stacks of major vendors. This will probably take
+ longer, because those vendors will have to figure out what they want to
+ do about the export controls.</P>
+<H4><A NAME="26_2_1_2">Current status</A></H4>
+<P>My initial goal of securing 5% of the net by Christmas '96 was not
+ met. It was an ambitious goal, and inspired me and others to work hard,
+ but was ultimately too ambitious. The protocols were in an early stage
+ of development, and needed a lot more protocol design before they could
+ be implemented. As of April 1999, we have released version 1.0 of the
+ software (<A href="ftp://ftp.xs4all.nl/freeswan/freeswan-1.0.tar.gz">
+freeswan-1.0.tar.gz</A>), which is suitable for setting up Virtual
+ Private Networks using shared secrets for authentication. It does not
+ yet do opportunistic encryption, or use DNSSEC for authentication;
+ those features are coming in a future release.</P>
+<DL>
+<DT>Protocols</DT>
+<DD>The low-level encrypted packet formats are defined. The system for
+ publishing keys and providing secure domain name service is defined.
+ The IP Security working group has settled on an NSA-sponsored protocol
+ for key agreement (called ISAKMP/Oakley), but it is still being worked
+ on, as the protocol and its documentation is too complex and
+ incomplete. There are prototype implementations of ISAKMP. The protocol
+ is not yet defined to enable opportunistic encryption or the use of
+ DNSSEC keys.</DD>
+<DT>Linux Implementation</DT>
+<DD>The Linux implementation has reached its first major release and is
+ ready for production use in manually-configured networks, using Linux
+ kernel version 2.0.36.</DD>
+<DT>Domain Name System Security</DT>
+<DD>There is now a release of BIND 8.2 that includes most DNS Security
+ features.
+<P>The first prototype implementation of Domain Name System Security was
+ funded by<A href="#DARPA"> DARPA</A> as part of their<A href="http://www.darpa.mil/ito/research/is/index.html">
+ Information Survivability program</A>.<A href="http://www.tis.com">
+ Trusted Information Systems</A> wrote a modified version of<A href="http://www.isc.org/bind.html">
+ BIND</A>, the widely-used Berkeley implementation of the Domain Name
+ System.</P>
+<P>TIS, ISC, and I merged the prototype into the standard version of
+ BIND. The first production version that supports KEY and SIG records is<B>
+ bind-4.9.5</B>. This or any later version of BIND will do for
+ publishing keys. It is available from the<A href="http://www.isc.org/bind.html">
+ Internet Software Consortium</A>. This version of BIND is not
+ export-controlled since it does not contain any cryptography. Later
+ releases starting with BIND 8.2 include cryptography for authenticating
+ DNS records, which is also exportable. Better documentation is needed.</P>
+</DD>
+</DL>
+<H4><A NAME="26_2_1_3">Why?</A></H4>
+<P>Because I can. I have made enough money from several successful
+ startup companies, that for a while I don't have to work to support
+ myself. I spend my energies and money creating the kind of world that
+ I'd like to live in and that I'd like my (future) kids to live in.
+ Keeping and improving on the civil rights we have in the United States,
+ as we move more of our lives into cyberspace, is a particular goal of
+ mine.</P>
+<H4><A NAME="26_2_1_4">What You Can Do</A></H4>
+<DL>
+<DT>Install the latest BIND at your site.</DT>
+<DD>You won't be able to publish any keys for your domain, until you
+ have upgraded your copy of BIND. The thing you really need from it is
+ the new version of<I> named</I>, the Name Daemon, which knows about the
+ new KEY and SIG record types. So, download it from the<A href="http://www.isc.org/bind.html">
+ Internet Software Consortium</A> and install it on your name server
+ machine (or get your system administrator, or Internet Service
+ Provider, to install it). Both your primary DNS site and all of your
+ secondary DNS sites will need the new release before you will be able
+ to publish your keys. You can tell which sites this is by running the
+ Unix command &quot;dig MYDOMAIN ns&quot; and seeing which sites are mentioned in
+ your NS (name server) records.</DD>
+<DT>Set up a Linux system and run a 2.0.x kernel on it</DT>
+<DD>Get a machine running Linux (say the 5.2 release from<A href="http://www.redhat.com">
+ Red Hat</A>). Give the machine two Ethernet cards.</DD>
+<DT>Install the Linux IPSEC (Freeswan) software</DT>
+<DD>If you're an experienced sysadmin or Linux hacker, install the
+ freeswan-1.0 release, or any later release or snapshot. These releases
+ do NOT provide automated &quot;opportunistic&quot; operation; they must be
+ manually configured for each site you wish to encrypt with.</DD>
+<DT>Get on the linux-ipsec mailing list</DT>
+<DD>The discussion forum for people working on the project, and testing
+ the code and documentation, is: linux-ipsec@clinet.fi. To join this
+ mailing list, send email to<A href="mailto:linux-ipsec-REQUEST@clinet.fi">
+ linux-ipsec-REQUEST@clinet.fi</A> containing a line of text that says
+ &quot;subscribe linux-ipsec&quot;. (You can later get off the mailing list the
+ same way -- just send &quot;unsubscribe linux-ipsec&quot;).</DD>
+<P></P>
+<DT>Check back at this web page every once in a while</DT>
+<DD>I update this page periodically, and there may be new information in
+ it that you haven't seen. My intent is to send email to the mailing
+ list when I update the page in any significant way, so subscribing to
+ the list is an alternative.</DD>
+</DL>
+<P>Would you like to help? I can use people who are willing to write
+ documentation, install early releases for testing, write cryptographic
+ code outside the United States, sell pre-packaged software or systems
+ including this technology, and teach classes for network administrators
+ who want to install this technology. To offer to help, send me email at
+ gnu@toad.com. Tell me what country you live in and what your
+ citizenship is (it matters due to the export control laws; personally I
+ don't care). Include a copy of your resume and the URL of your home
+ page. Describe what you'd like to do for the project, and what you're
+ uniquely qualified for. Mention what other volunteer projects you've
+ been involved in (and how they worked out). Helping out will require
+ that you be able to commit to doing particular things, meet your
+ commitments, and be responsive by email. Volunteer projects just don't
+ work without those things.</P>
+<H4><A NAME="26_2_1_5">Related projects</A></H4>
+<DL>
+<DT>IPSEC for NetBSD</DT>
+<DD>This prototype implementation of the IP Security protocols is for
+ another free operating system.<A href="ftp://ftp.funet.fi/pub/unix/security/net/ip/BSDipsec.tar.gz">
+ Download BSDipsec.tar.gz</A>.</DD>
+<DT>IPSEC for<A href="http://www.openbsd.org"> OpenBSD</A></DT>
+<DD>This prototype implementation of the IP Security protocols is for
+ yet another free operating system. It is directly integrated into the
+ OS release, since the OS is maintained in Canada, which has freedom of
+ speech in software.</DD>
+</DL>
+<H3><A name="policestate">Stopping wholesale monitoring</A></H3>
+<P>From a message project leader John Gilmore posted to the mailing
+ list:</P>
+<PRE>John Denker wrote:
+
+&gt; Indeed there are several ways in which the documentation overstates the 
+&gt; scope of what this project does -- starting with the name 
+&gt; FreeS/WAN.  There's a big difference between having an encrypted IP tunnel 
+&gt; versus having a Secure Wide-Area Network.  This software does a fine job of 
+&gt; the former, which is necessary but not sufficient for the latter.
+
+The goal of the project is to make it very hard to tap your wide area
+communications.  The current system provides very good protection
+against passive attacks (wiretapping and those big antenna farms).
+Active attacks, which involve the intruder sending packets to your
+system (like packets that break into sendmail and give them a root
+shell :-) are much harder to guard against.  Active attacks that
+involve sending people (breaking into your house and replacing parts
+of your computer with ones that transmit what you're doing) are also
+much harder to guard against.  Though we are putting effort into
+protecting against active attacks, it's a much bigger job than merely
+providing strong encryption.  It involves general computer security,
+and general physical security, which are two very expensive problems
+for even a site to solve, let alone to build into a whole society.
+
+The societal benefit of building an infrastructure that protects
+well against passive attacks is that it makes it much harder to do
+undetected bulk monitoring of the population.  It's a defense against
+police-states, not against policemen.
+
+Policemen can put in the effort required to actively attack sites that
+they have strong suspicions about.  But police states won't be able to
+build systems that automatically monitor everyone's communications.
+Either they will be able to monitor only a small subset of the
+populace (by targeting those who screwed up their passive security),
+or their monitoring activities will be detectable by those monitored
+(active attacks leave packet traces or footprints), which can then be
+addressed through the press and through political means if they become
+too widespread.
+
+FreeS/WAN does not protect very well against traffic analysis, which
+is a kind of widespread police-state style monitoring that still
+reveals significant information (who's talking to who) without
+revealing the contents of what was said.  Defenses against traffic
+analysis are an open research problem.  Zero Knowledge Systems is
+actively deploying a system designed to thwart it, designed by Ian
+Goldberg.  The jury is out on whether it actually works; a lot more
+experience with it will be needed.</PRE>
+<P>Notes on things mentioned in that message:</P>
+<UL>
+<LI>Denker is a co-author of a<A href="#applied"> paper</A> on a large
+ FreeS/WAN application.</LI>
+<LI>Information on Zero Knowledge is on their<A href="http://www.zks.net/">
+ web site</A>. Their Freedom product, designed to provide untracable
+ pseudonyms for use on the net, is no longer marketed.</LI>
+<LI>Another section of our documentation discusses ways to<A href="#traffic.resist">
+ resist traffic analysis</A>.</LI>
+</UL>
+<H2><A name="weak">Government promotion of weak crypto</A></H2>
+<P>Various groups, especially governments and especially the US
+ government, have a long history of advocating various forms of bogus
+ security.</P>
+<P>We regard bogus security as extremely dangerous. If users are
+ deceived into relying on bogus security, then they may be exposed to
+ large risks. They would be better off having no security and knowing
+ it. At least then they would be careful about what they said.</P>
+<P><STRONG>Avoiding bogus security is a key design criterion for
+ everything we do in FreeS/WAN</STRONG>. The most conspicuous example is
+ our refusal to support<A href="#desnotsecure"> single DES</A>. Other
+ IPsec &quot;features&quot; which we do not implement are discussed in our<A href="#dropped">
+ compatibility</A> document.</P>
+<H3><A name="escrow">Escrowed encryption</A></H3>
+<P>Various governments have made persistent attempts to encourage or
+ mandate &quot;escrowed encrytion&quot;, also called &quot;key recovery&quot;, or GAK for
+ &quot;government access to keys&quot;. The idea is that cryptographic keys be
+ held by some third party and turned over to law enforcement or security
+ agencies under some conditions.</P>
+<PRE>  Mary had a little key - she kept it in escrow,
+  and every thing that Mary said,
+  the feds were sure to know.</PRE>
+<P>A<A href="#quotes"> crypto quotes</A> page attributes this to<A href="http://www.scramdisk.clara.net/">
+ Sam Simpson</A>.</P>
+<P>There is an excellent paper available on<A href="http://www.cdt.org/crypto/risks98/">
+ Risks of Escrowed Encryption</A>, from a group of cryptographic
+ luminaries which included our project leader.</P>
+<P>Like any unnecessary complication, GAK tends to weaken security of
+ any design it infects. For example:</P>
+<UL>
+<LI>Matt Blaze found a fatal flaw in the US government's Clipper chip
+ shortly after design information became public. See his paper &quot;Protocol
+ Failure in the Escrowed Encryption Standard&quot; on his<A href="http://www.crypto.com/papers/">
+ papers</A> page.</LI>
+<LI>a rather<A href="http://www.pgp.com/other/advisories/adk.asp"> nasty
+ bug</A> was found in the &quot;additional decryption keys&quot; &quot;feature&quot; of some
+ releases of<A href="#PGP"> PGP</A></LI>
+</UL>
+<P>FreeS/WAN does not support escrowed encryption, and never will.</P>
+<H3><A name="shortkeys">Limited key lengths</A></H3>
+<P>Various governments, and some vendors, have also made persistent
+ attempts to convince people that:</P>
+<UL>
+<LI>weak systems are sufficient for some data</LI>
+<LI>strong cryptography should be reserved for cases where the extra
+ overheads are justified</LI>
+</UL>
+<P><STRONG>This is utter nonsense</STRONG>.</P>
+<P>Weak systems touted include:</P>
+<UL>
+<LI>the ludicrously weak (deliberately crippled) 40-bit ciphers that
+ until recently were all various<A href="#exlaw"> export laws</A>
+ allowed</LI>
+<LI>56-bit single DES, discussed<A href="#desnotsecure"> below</A></LI>
+<LI>64-bit symmetric ciphers and 512-bit RSA, the maximums for
+ unrestricted export under various current laws</LI>
+</UL>
+<P>The notion that choice of ciphers or keysize should be determined by
+ a trade-off between security requirements and overheads is pure
+ bafflegab.</P>
+<UL>
+<LI>For most<A href="#symmetric"> symmetric ciphers</A>, it is simply a
+ lie. Any block cipher has some natural maximum keysize inherent in the
+ design -- 128 bits for<A href="#IDEA"> IDEA</A> or<A href="#CAST128">
+ CAST-128</A>, 256 for Serpent or Twofish, 448 for<A href="#Blowfish">
+ Blowfish</A> and 2048 for<A href="#RC4"> RC4</A>. Using a key size
+ smaller than that limit gives<EM> exactly zero</EM> savings in
+ overhead. The crippled 40-bit or 64-bit version of the cipher provides<EM>
+ no advantage whatsoever</EM>.</LI>
+<LI><A href="#AES">AES</A> uses 10 rounds with 128-bit keys, 12 rounds
+ for 192-bit and 14 rounds for 256-bit, so there actually is a small
+ difference in overhead, but not enough to matter in most applications.</LI>
+<LI>For<A href="#3DES"> triple DES</A> there is a grain of truth in the
+ argument. 3DES is indeed three times slower than single DES. However,
+ the solution is not to use the insecure single DES, but to pick a
+ faster secure cipher.<A href="#CAST128"> CAST-128</A>,<A href="#Blowfish">
+ Blowfish</A> and the<A href="#AES"> AES candidate</A> ciphers are are
+ all considerably faster in software than DES (let alone 3DES!), and
+ apparently secure.</LI>
+<LI>For<A href="#public"> public key</A> techniques, there are extra
+ overheads for larger keys, but they generally do not affect overall
+ performance significantly. Practical public key applications are
+ usually<A href="#hybrid"> hybrid</A> systems in which the bulk of the
+ work is done by a symmetric cipher. The effect of increasing the cost
+ of the public key operations is typically negligible because the public
+ key operations use only a tiny fraction of total resources.
+<P>For example, suppose public key operations use use 1% of the time in
+ a hybrid system and you triple the cost of public key operations. The
+ cost of symmetric cipher operations is unchanged at 99% of the original
+ total cost, so the overall effect is a jump from 99 + 1 = 100 to 99 + 3
+ = 102, a 2% rise in system cost.</P>
+</LI>
+</UL>
+<P>In short,<STRONG> there has never been any technical reason to use
+ inadequate ciphers</STRONG>. The only reason there has ever been for
+ anyone to use such ciphers is that government agencies want weak
+ ciphers used so that they can crack them. The alleged savings are
+ simply propaganda.</P>
+<PRE>   Mary had a little key (It's all she could export),
+   and all the email that she sent was opened at the Fort.</PRE>
+<P>A<A href="#quotes"> crypto quotes</A> page attributes this to<A href="http://theory.lcs.mit.edu:80/~rivest/">
+ Ron Rivest</A>. NSA headquarters is at Fort Meade, Maryland.</P>
+<P>Our policy in FreeS/WAN is to use only cryptographic components with
+ adequate keylength and no known weaknesses.</P>
+<UL>
+<LI>We do not implement single DES because it is clearly<A href="#desnotsecure">
+ insecure</A>, so implemeting it would violate our policy of avoiding
+ bogus security. Our default cipher is<A href="#3DES"> 3DES</A></LI>
+<LI>Similarly, we do not implement the 768-bit Group 1 for<A href="#DH">
+ Diffie-Hellman</A> key negotiation. We provide only the 1024-bit Group
+ 2 and 1536-bit Group 5.</LI>
+</UL>
+<P>Detailed discussion of which IPsec features we implement or omit is
+ in out<A href="compat.html"> compatibility document</A>.</P>
+<P>These decisions imply that we cannot fully conform to the IPsec RFCs,
+ since those have DES as the only required cipher and Group 1 as the
+ only required DH group. (In our view, the standards were subverted into
+ offerring bogus security.) Fortunately, we can still interoperate with
+ most other IPsec implementations since nearly all implementers provide
+ at least 3DES and Group 2 as well.</P>
+<P>We hope that eventually the RFCs will catch up with our (and others')
+ current practice and reject dubious components. Some of our team and a
+ number of others are working on this in<A href="#ietf"> IETF</A>
+ working groups.</P>
+<H4><A NAME="26_3_2_1">Some real trade-offs</A></H4>
+<P>Of course, making systems secure does involve costs, and trade-offs
+ can be made between cost and security. However, the real trade-offs
+ have nothing to do with using weaker ciphers.</P>
+<P>There can be substantial hardware and software costs. There are often
+ substantial training costs, both to train administrators and to
+ increase user awareness of security issues and procedures. There are
+ almost always substantial staff or contracting costs.</P>
+<P>Security takes staff time for planning, implementation, testing and
+ auditing. Some of the issues are subtle; you need good (hence often
+ expensive) people for this. You also need people to monitor your
+ systems and respond to problems. The best safe ever built is insecure
+ if an attacker can work on it for days without anyone noticing. Any
+ computer is insecure if the administrator is &quot;too busy&quot; to check the
+ logs.</P>
+<P>Moreover, someone in your organisation (or on contract to it) needs
+ to spend considerable time keeping up with new developments. EvilDoers<EM>
+ will</EM> know about new attacks shortly after they are found. You need
+ to know about them before your systems are attacked. If your vendor
+ provides a patch, you need to apply it. If the vendor does nothing, you
+ need to complain or start looking for another vendor.</P>
+<P>For a fairly awful example, see this<A href="http://www.sans.org/newlook/alerts/NTE-bank.htm">
+ report</A>. In that case over a million credit card numbers were taken
+ from e-commerce sites, using security flaws in Windows NT servers.
+ Microsoft had long since released patches for most or all of the flaws,
+ but the site administrators had not applied them.</P>
+<P>At an absolute minimum, you must do something about such issues<EM>
+ before</EM> an exploitation tool is posted to the net for downloading
+ by dozens of &quot;script kiddies&quot;. Such a tool might appear at any time
+ from the announcement of the security hole to several months later.
+ Once it appears, anyone with a browser and an attitude can break any
+ system whose administrators have done nothing about the flaw.</P>
+<P>Compared to those costs, cipher overheads are an insignificant factor
+ in the cost of security.</P>
+<P>The only thing using a weak cipher can do for you is to cause all
+ your other investment to be wasted.</P>
+<H2><A name="exlaw">Cryptography Export Laws</A></H2>
+<P>Many nations restrict the export of cryptography and some restrict
+ its use by their citizens or others within their borders.</P>
+<H3><A name="USlaw">US Law</A></H3>
+<P>US laws, as currently interpreted by the US government, forbid export
+ of most cryptographic software from the US in machine-readable form
+ without government permission. In general, the restrictions apply even
+ if the software is widely-disseminated or public-domain and even if it
+ came from outside the US originally. Cryptography is legally a munition
+ and export is tightly controlled under the<A href="#EAR"> EAR</A>
+ Export Administration Regulations.</P>
+<P>If you are a US citizen, your brain is considered US territory no
+ matter where it is physically located at the moment. The US believes
+ that its laws apply to its citizens everywhere, not just within the US.
+ Providing technical assistance or advice to foreign &quot;munitions&quot;
+ projects is illegal. The US government has very little sense of humor
+ about this issue and does not consider good intentions to be sufficient
+ excuse. Beware.</P>
+<P>The<A href="http://www.bxa.doc.gov/Encryption/"> official website</A>
+ for these regulations is run by the Commerce Department's Bureau of
+ Export Administration (BXA).</P>
+<P>The<A href="http://www.eff.org/bernstein/"> Bernstein case</A>
+ challenges the export restrictions on Constitutional grounds. Code is
+ speech so restrictions on export of code violate the First Amendment's
+ free speech provisions. This argument has succeeded in two levels of
+ court so far. It is quite likely to go on to the Supreme Court.</P>
+<P>The regulations were changed substantially in January 2000,
+ apparently as a government attempt to get off the hook in the Bernstein
+ case. It is now legal to export public domain source code for
+ encryption, provided you notify the<A href="#BXA"> BXA</A>.</P>
+<P>There are, however, still restrictions in force. Moreover, the
+ regulations can still be changed again whenever the government chooses
+ to do so. Short of a Supreme Court ruling (in the Berstein case or
+ another) that overturns the regulations completely, the problem of
+ export regulation is not likely to go away in the forseeable future.</P>
+<H4><A name="UScontrib">US contributions to FreeS/WAN</A></H4>
+<P>The FreeS/WAN project<STRONG> cannot accept software contributions,<EM>
+ not even small bug fixes</EM>, from US citizens or residents</STRONG>.
+ We want it to be absolutely clear that our distribution is not subject
+ to US export law. Any contribution from an American might open that
+ question to a debate we'd prefer to avoid. It might also put the
+ contributor at serious legal risk.</P>
+<P>Of course Americans can still make valuable contributions (many
+ already have) by reporting bugs, or otherwise contributing to
+ discussions, on the project<A href="mail.html"> mailing list</A>. Since
+ the list is public, this is clearly constitutionally protected free
+ speech.</P>
+<P>Note, however, that the export laws restrict Americans from providing
+ technical assistance to foreign &quot;munitions&quot; projects. The government
+ might claim that private discussions or correspondence with FreeS/WAN
+ developers were covered by this. It is not clear what the courts would
+ do with such a claim, so we strongly encourage Americans to use the
+ list rather than risk the complications.</P>
+<H3><A name="wrong">What's wrong with restrictions on cryptography</A></H3>
+<P>Some quotes from prominent cryptography experts:</P>
+<BLOCKQUOTE> The real aim of current policy is to ensure the continued
+ effectiveness of US information warfare assets against individuals,
+ businesses and governments in Europe and elsewhere.
+<BR><A href="http://www.cl.cam.ac.uk/users/rja14"> Ross Anderson,
+ Cambridge University</A></BLOCKQUOTE><BLOCKQUOTE> If the government
+ were honest about its motives, then the debate about crypto export
+ policy would have ended years ago.
+<BR><A href="http://www.counterpane.com"> Bruce Schneier, Counterpane
+ Systems</A></BLOCKQUOTE><BLOCKQUOTE> The NSA regularly lies to people
+ who ask it for advice on export control. They have no reason not to;
+ accomplishing their goal by any legal means is fine by them. Lying by
+ government employees is legal.
+<BR> John Gilmore.</BLOCKQUOTE>
+<P>The Internet Architecture Board (IAB) and the Internet Engineering
+ Steering Group (IESG) made a<A href="iab-iesg.stmt"> strong statement</A>
+ in favour of worldwide access to strong cryptography. Essentially the
+ same statement is in the appropriately numbered<A href="ftp://ftp.isi.edu/in-notes/rfc1984.txt">
+ RFC 1984</A>. Two critical paragraphs are:</P>
+<BLOCKQUOTE> ... various governments have actual or proposed policies on
+ access to cryptographic technology ...
+<P>(a) ... export controls ...
+<BR> (b) ... short cryptographic keys ...
+<BR> (c) ... keys should be in the hands of the government or ...
+<BR> (d) prohibit the use of cryptology ...</P>
+<P>We believe that such policies are against the interests of consumers
+ and the business community, are largely irrelevant to issues of
+ military security, and provide only a marginal or illusory benefit to
+ law enforcement agencies, ...</P>
+<P>The IAB and IESG would like to encourage policies that allow ready
+ access to uniform strong cryptographic technology for all Internet
+ users in all countries.</P>
+</BLOCKQUOTE>
+<P>Our goal in the FreeS/WAN project is to build just such &quot;strong
+ cryptographic technology&quot; and to distribute it &quot;for all Internet users
+ in all countries&quot;.</P>
+<P>More recently, the same two bodies (IESG and IAB) have issued<A href="ftp://ftp.isi.edu/in-notes/rfc2804.txt">
+ RFC 2804</A> on why the IETF should not build wiretapping capabilities
+ into protocols for the convenience of security or law enforcement
+ agenicies. The abstract from that document is:</P>
+<BLOCKQUOTE> The Internet Engineering Task Force (IETF) has been asked
+ to take a position on the inclusion into IETF standards-track documents
+ of functionality designed to facilitate wiretapping.
+<P>This memo explains what the IETF thinks the question means, why its
+ answer is &quot;no&quot;, and what that answer means.</P>
+</BLOCKQUOTE> A quote from the debate leading up to that RFC:<BLOCKQUOTE>
+ We should not be building surveillance technology into standards. Law
+ enforcement was not supposed to be easy. Where it is easy, it's called
+ a police state.
+<BR> Jeff Schiller of MIT, in a discussion of FBI demands for wiretap
+ capability on the net, as quoted by<A href="http://www.wired.com/news/politics/0,1283,31895,00.html">
+ Wired</A>.</BLOCKQUOTE>
+<P>The<A href="http://www.ietf.org/mailman/listinfo/raven"> Raven</A>
+ mailing list was set up for this IETF discussion.</P>
+<P>Our goal is to go beyond that RFC and prevent Internet wiretapping
+ entirely.</P>
+<H3><A name="Wassenaar">The Wassenaar Arrangement</A></H3>
+<P>Restrictions on the export of cryptography are not just US policy,
+ though some consider the US at least partly to blame for the policies
+ of other nations in this area.</P>
+<P>A number of countries:</P>
+<P>Argentina, Australia, Austria, Belgium, Bulgaria, Canada, Czech
+ Republic, Denmark, Finland, France, Germany, Greece, Hungary, Ireland,
+ Italy, Japan, Luxembourg, Netherlands, New Zealand, Norway, Poland,
+ Portugal, Republic of Korea, Romania, Russian Federation, Slovak
+ Republic, Spain, Sweden, Switzerland, Turkey, Ukraine, United Kingdom
+ and United States</P>
+<P>have signed the Wassenaar Arrangement which restricts export of
+ munitions and other tools of war. Cryptographic sofware is covered
+ there.</P>
+<P>Wassenaar details are available from the<A href="http://www.wassenaar.org/">
+ Wassenaar Secretariat</A>, and elsewhere in a more readable<A href="http://www.fitug.de/news/wa/index.html">
+ HTML version</A>.</P>
+<P>For a critique see the<A href="http://www.gilc.org/crypto/wassenaar">
+ GILC site</A>:</P>
+<BLOCKQUOTE> The Global Internet Liberty Campaign (GILC) has begun a
+ campaign calling for the removal of cryptography controls from the
+ Wassenaar Arrangement.
+<P>The aim of the Wassenaar Arrangement is to prevent the build up of
+ military capabilities that threaten regional and international security
+ and stability . . .</P>
+<P>There is no sound basis within the Wassenaar Arrangement for the
+ continuation of any export controls on cryptographic products.</P>
+</BLOCKQUOTE>
+<P>We agree entirely.</P>
+<P>An interesting analysis of Wassenaar can be found on the<A href="http://www.cyber-rights.org/crypto/wassenaar.htm">
+ cyber-rights.org</A> site.</P>
+<H3><A name="status">Export status of Linux FreeS/WAN</A></H3>
+<P>We believe our software is entirely exempt from these controls since
+ the Wassenaar<A href="http://www.wassenaar.org/list/GTN%20and%20GSN%20-%2099.pdf">
+ General Software Note</A> says:</P>
+<BLOCKQUOTE> The Lists do not control &quot;software&quot; which is either:
+<OL>
+<LI>Generally available to the public by . . . retail . . . or</LI>
+<LI>&quot;In the public domain&quot;.</LI>
+</OL>
+</BLOCKQUOTE>
+<P>There is a note restricting some of this, but it is a sub-heading
+ under point 1, so it appears not to apply to public domain software.</P>
+<P>Their glossary defines &quot;In the public domain&quot; as:</P>
+<BLOCKQUOTE> . . . &quot;technology&quot; or &quot;software&quot; which has been made
+ available without restrictions upon its further dissemination.
+<P>N.B. Copyright restrictions do not remove &quot;technology&quot; or &quot;software&quot;
+ from being &quot;in the public domain&quot;.</P>
+</BLOCKQUOTE>
+<P>We therefore believe that software freely distributed under the<A href="#GPL">
+ GNU Public License</A>, such as Linux FreeS/WAN, is exempt from
+ Wassenaar restrictions.</P>
+<P>Most of the development work is being done in Canada. Our
+ understanding is that the Canadian government accepts this
+ interpretation.</P>
+<UL>
+<LI>A web statement of<A href="http://www.dfait-maeci.gc.ca/~eicb/notices/ser113-e.htm">
+ Canadian policy</A> is available from the Department of Foreign Affairs
+ and International Trade.</LI>
+<LI>Another document from that department states that<A href="http://www.dfait-maeci.gc.ca/~eicb/export/gr1_e.htm">
+ public domain software</A> is exempt from the export controls.</LI>
+<LI>A researcher's<A href="http://insight.mcmaster.ca/org/efc/pages/doc/crypto-export.html">
+ analysis</A> of Canadian policy is also available.</LI>
+</UL>
+<P>Recent copies of the freely modifiable and distributable source code
+ exist in many countries. Citizens all over the world participate in its
+ use and evolution, and guard its ongoing distribution. Even if Canadian
+ policy were to change, the software would continue to evolve in
+ countries which do not restrict exports, and would continue to be
+ imported from there into unfree countries. &quot;The Net culture treats
+ censorship as damage, and routes around it.&quot;</P>
+<H3><A name="help">Help spread IPsec around</A></H3>
+<P>You can help. If you don't know of a Linux FreeS/WAN archive in your
+ own country, please download it now to your personal machine, and
+ consider making it publicly accessible if that doesn't violate your own
+ laws. If you have the resources, consider going one step further and
+ setting up a mirror site for the whole<A href="#munitions"> munitions</A>
+ Linux crypto software archive.</P>
+<P>If you make Linux CD-ROMs, please consider including this code, in a
+ way that violates no laws (in a free country, or in a domestic-only CD
+ product).</P>
+<P>Please send a note about any new archive mirror sites or CD
+ distributions to linux-ipsec@clinet.fi so we can update the
+ documentation.</P>
+<P>Lists of current<A href="#sites"> mirror sites</A> and of<A href="#distwith">
+ distributions</A> which include FreeS/WAN are in our introduction
+ section.</P>
+<H2><A name="desnotsecure">DES is Not Secure</A></H2>
+<P>DES, the<STRONG> D</STRONG>ata<STRONG> E</STRONG>ncryption<STRONG> S</STRONG>
+tandard, can no longer be considered secure. While no major flaws in its
+ innards are known, it is fundamentally inadequate because its<STRONG>
+ 56-bit key is too short</STRONG>. It is vulnerable to<A href="#brute">
+ brute-force search</A> of the whole key space, either by large
+ collections of general-purpose machines or even more quickly by
+ specialized hardware. Of course this also applies to<STRONG> any other
+ cipher with only a 56-bit key</STRONG>. The only reason anyone could
+ have for using a 56 or 64-bit key is to comply with various<A href="exportlaw.html">
+ export laws</A> intended to ensure the use of breakable ciphers.</P>
+<P>Non-government cryptologists have been saying DES's 56-bit key was
+ too short for some time -- some of them were saying it in the 70's when
+ DES became a standard -- but the US government has consistently
+ ridiculed such suggestions.</P>
+<P>A group of well-known cryptographers looked at key lengths in a<A href="http://www.counterpane.com/keylength.html">
+ 1996 paper</A>. They suggested a<EM> minimum</EM> of 75 bits to
+ consider an existing cipher secure and a<EM> minimum of 90 bits for new
+ ciphers</EM>. More recent papers, covering both<A href="#symmetric">
+ symmetric</A> and<A href="#public"> public key</A> systems are at<A href="http://www.cryptosavvy.com/">
+ cryptosavvy.com</A> and<A href="http://www.rsasecurity.com/rsalabs/bulletins/bulletin13.html">
+ rsa.com</A>. For all algorithms, the minimum keylengths recommended in
+ such papers are significantly longer than the maximums allowed by
+ various export laws.</P>
+<P>In a<A href="http://www.privacy.nb.ca/cryptography/archives/cryptography/html/1998-09/0095.html">
+ 1998 ruling</A>, a German court described DES as &quot;out-of-date and not
+ safe enough&quot; and held a bank liable for using it.</P>
+<H3><A name="deshware">Dedicated hardware breaks DES in a few days</A></H3>
+<P>The question of DES security has now been settled once and for all.
+ In early 1998, the<A href="http://www.eff.org/"> Electronic Frontier
+ Foundation</A> built a<A href="http://www.eff.org/descracker.html">
+ DES-cracking machine</A>. It can find a DES key in an average of a few
+ days' search. The details of all this, including complete code listings
+ and complete plans for the machine, have been published in<A href="#EFF">
+<CITE> Cracking DES</CITE></A>, by the Electronic Frontier Foundation.</P>
+<P>That machine cost just over $200,000 to design and build. &quot;Moore's
+ Law&quot; is that machines get faster (or cheaper, for the same speed) by
+ roughly a factor of two every 18 months. At that rate, their $200,000
+ in 1998 becomes $50,000 in 2001.</P>
+<P>However, Moore's Law is not exact and the $50,000 estimate does not
+ allow for the fact that a copy based on the published EFF design would
+ cost far less than the original. We cannot say exactly what such a
+ cracker would cost today, but it would likely be somewhere between
+ $10,000 and $100,000.</P>
+<P>A large corporation could build one of these out of petty cash. The
+ cost is low enough for a senior manager to hide it in a departmental
+ budget and avoid having to announce or justify the project. Any
+ government agency, from a major municipal police force up, could afford
+ one. Or any other group with a respectable budget -- criminal
+ organisations, political groups, labour unions, religious groups, ...
+ Or any millionaire with an obsession or a grudge, or just strange taste
+ in toys.</P>
+<P>One might wonder if a private security or detective agency would have
+ one for rent. They wouldn't need many clients to pay off that
+ investment.</P>
+<H3><A name="spooks">Spooks may break DES faster yet</A></H3>
+<P>As for the security and intelligence agencies of various nations,
+ they may have had DES crackers for years, and theirs may be much
+ faster. It is difficult to make most computer applications work well on
+ parallel machines, or to design specialised hardware to accelerate
+ them. Cipher-cracking is one of the very few exceptions. It is entirely
+ straightforward to speed up cracking by just adding hardware. Within
+ very broad limits, you can make it as fast as you like if you have the
+ budget. The EFF's $200,000 machine breaks DES in a few days. An<A href="http://www.planepage.com/">
+ aviation website</A> gives the cost of a B1 bomber as $200,000,000.
+ Spending that much, an intelligence agency could break DES in an
+ average time of<EM> six and a half minutes</EM>.</P>
+<P>That estimate assumes they use the EFF's 1998 technology and just
+ spend more money. They may have an attack that is superior to brute
+ force, they quite likely have better chip technology (Moore's law, a
+ bigger budget, and whatever secret advances they may have made) and of
+ course they may have spent the price of an aircraft carrier, not just
+ one aircraft.</P>
+<P>In short, we have<EM> no idea</EM> how quickly these organisations
+ can break DES. Unless they're spectacularly incompetent or horribly
+ underfunded, they can certainly break it, but we cannot guess how
+ quickly. Pick any time unit between days and milliseconds; none is
+ entirely unbelievable. More to the point, none of them is of any
+ comfort if you don't want such organisations reading your
+ communications.</P>
+<P>Note that this may be a concern even if nothing you do is a threat to
+ anyone's national security. An intelligence agency might well consider
+ it to be in their national interest for certain companies to do well.
+ If you're competing against such companies in a world market and that
+ agency can read your secrets, you have a serious problem.</P>
+<P>One might wonder about technology the former Soviet Union and its
+ allies developed for cracking DES during the Cold War. They must have
+ tried; the cipher was an American standard and widely used. Certainly
+ those countries have some fine mathematicians, and those agencies had
+ budget. How well did they succeed? Is their technology now for sale or
+ rent?</P>
+<H3><A name="desnet">Networks break DES in a few weeks</A></H3>
+<P>Before the definitive EFF effort, DES had been cracked several times
+ by people using many machines. See this<A href="http://www.distributed.net/pressroom/DESII-1-PR.html">
+ press release</A> for example.</P>
+<P>A major corporation, university, or government department could break
+ DES by using spare cycles on their existing collection of computers, by
+ dedicating a group of otherwise surplus machines to the problem, or by
+ combining the two approaches. It might take them weeks or months,
+ rather than the days required for the EFF machine, but they could do
+ it.</P>
+<P>What about someone working alone, without the resources of a large
+ organisation? For them, cracking DES will not be easy, but it may be
+ possible. A few thousand dollars buys a lot of surplus workstations. A
+ pile of such machines will certainly heat your garage nicely and might
+ break DES in a few months or years. Or enroll at a university and use
+ their machines. Or use an employer's machines. Or crack security
+ somewhere and steal the resources to crack a DES key. Or write a virus
+ that steals small amounts of resources on many machines. Or . . .</P>
+<P>None of these approaches are easy or break DES really quickly, but an
+ attacker only needs to find one that is feasible and breaks DES quickly
+ enough to be dangerous. How much would you care to bet that this will
+ be impossible if the attacker is clever and determined? How valuable is
+ your data? Are you authorised to risk it on a dubious bet?</P>
+<H3><A name="no_des">We disable DES</A></H3>
+<P>In short, it is now absolutely clear that<STRONG> DES is not secure</STRONG>
+ against</P>
+<UL>
+<LI>any<STRONG> well-funded opponent</STRONG></LI>
+<LI>any opponent (even a penniless one) with access (even stolen access)
+ to<STRONG> enough general purpose computers</STRONG></LI>
+</UL>
+<P>That is why<STRONG> Linux FreeS/WAN disables all transforms which use
+ plain DES</STRONG> for encryption.</P>
+<P>DES is in the source code, because we need DES to implement our
+ default encryption transform,<A href="#3DES"> Triple DES</A>.<STRONG>
+ We urge you not to use single DES</STRONG>. We do not provide any easy
+ way to enable it in FreeS/WAN, and our policy is to provide no
+ assistance to anyone wanting to do so.</P>
+<H3><A name="40joke">40-bits is laughably weak</A></H3>
+<P>The same is true, in spades, of ciphers -- DES or others -- crippled
+ by 40-bit keys, as many ciphers were required to be until recently
+ under various<A href="#exlaw"> export laws</A>. A brute force search of
+ such a cipher's keyspace is 2<SUP>16</SUP> times faster than a similar
+ search against DES. The EFF's machine can do a brute-force search of a
+ 40-bit key space in<EM> seconds</EM>. One contest to crack a 40-bit
+ cipher was won by a student<A href="http://catless.ncl.ac.uk/Risks/18.80.html#subj1">
+ using a few hundred idle machines at his university</A>. It took only
+ three and half hours.</P>
+<P>We do not, and will not, implement any 40-bit cipher.</P>
+<H3><A name="altdes">Triple DES is almost certainly secure</A></H3>
+<P><A href="#3DES">Triple DES</A>, usually abbreviated 3DES, applies DES
+ three times, with three different keys. DES seems to be basically an
+ excellent cipher design; it has withstood several decades of intensive
+ analysis without any disastrous flaws being found. It's only major flaw
+ is that the small keyspace allows brute force attacks to succeeed.
+ Triple DES enlarges the key space to 168 bits, making brute-force
+ search a ridiculous impossibility.</P>
+<P>3DES is currently the only block cipher implemented in FreeS/WAN.
+ 3DES is, unfortunately, about 1/3 the speed of DES, but modern CPUs
+ still do it at quite respectable speeds. Some<A href="#benchmarks">
+ speed measurements</A> for our code are available.</P>
+<H3><A name="aes.ipsec">AES in IPsec</A></H3>
+<P>The<A href="#AES"> AES</A> project has chosen a replacement for DES,
+ a new standard cipher for use in non-classified US government work and
+ in regulated industries such as banking. This cipher will almost
+ certainly become widely used for many applications, including IPsec.</P>
+<P>The winner, announced in October 2000 after several years of analysis
+ and discussion, was the<A href="http://www.esat.kuleuven.ac.be/~rijmen/rijndael/">
+ Rijndael</A> cipher from two Belgian designers.</P>
+<P>It is almost certain that FreeS/WAN will add AES support.<A href="#patch">
+ AES patches</A> are already available.</P>
+<H2><A name="press">Press coverage of Linux FreeS/WAN:</A></H2>
+<H3><A NAME="26_6_1">FreeS/WAN 1.0 press</A></H3>
+<UL>
+<LI><A href="http://www.wired.com/news/news/technology/story/19136.html">
+Wired</A> &quot;Linux-Based Crypto Stops Snoops&quot;, James Glave April 15 1999</LI>
+<LI><A href="http://slashdot.org/articles/99/04/15/1851212.shtml">
+Slashdot</A></LI>
+<LI><A href="http://dgl.com/itinfo/1999/it990415.html">DGL</A>, Damar
+ Group Limited; looking at FreeS/WAN from a perspective of business
+ computing</LI>
+<LI><A href="http://linuxtoday.com/stories/5010.html">Linux Today</A></LI>
+<LI><A href="http://www.tbtf.com/archive/1999-04-21.html#Tcep">TBTF</A>,
+ Tasty Bits from the Technology Front</LI>
+<LI><A href="http://www.salonmagazine.com/tech/log/1999/04/16/encryption/index.html">
+Salon Magazine</A> &quot;Free Encryption Takes a Big Step&quot;</LI>
+</UL>
+<H3><A name="release">Press release for version 1.0</A></H3>
+<PRE>        Strong Internet Privacy Software Free for Linux Users Worldwide
+
+Toronto, ON, April 14, 1999 - 
+
+The Linux FreeS/WAN project today released free software to protect
+the privacy of Internet communications using strong encryption codes.
+FreeS/WAN automatically encrypts data as it crosses the Internet, to
+prevent unauthorized people from receiving or modifying it.  One
+ordinary PC per site runs this free software under Linux to become a
+secure gateway in a Virtual Private Network, without having to modify
+users' operating systems or application software.  The project built
+and released the software outside the United States, avoiding US
+government regulations which prohibit good privacy protection.
+FreeS/WAN version 1.0 is available immediately for downloading at
+http://www.xs4all.nl/~freeswan/.
+
+&quot;Today's FreeS/WAN release allows network administrators to build
+excellent secure gateways out of old PCs at no cost, or using a cheap
+new PC,&quot; said John Gilmore, the entrepreneur who instigated the
+project in 1996.  &quot;They can build operational experience with strong
+network encryption and protect their users' most important
+communications worldwide.&quot;
+
+&quot;The software was written outside the United States, and we do not
+accept contributions from US citizens or residents, so that it can be
+freely published for use in every country,&quot; said Henry Spencer, who
+built the release in Toronto, Canada.  &quot;Similar products based in the
+US require hard-to-get government export licenses before they can be
+provided to non-US users, and can never be simply published on a Web
+site.  Our product is freely available worldwide for immediate
+downloading, at no cost.&quot;
+
+FreeS/WAN provides privacy against both quiet eavesdropping (such as
+&quot;packet sniffing&quot;) and active attempts to compromise communications
+(such as impersonating participating computers).  Secure &quot;tunnels&quot; carry
+information safely across the Internet between locations such as a
+company's main office, distant sales offices, and roaming laptops.  This
+protects the privacy and integrity of all information sent among those
+locations, including sensitive intra-company email, financial transactions
+such as mergers and acquisitions, business negotiations, personal medical
+records, privileged correspondence with lawyers, and information about
+crimes or civil rights violations.  The software will be particularly
+useful to frequent wiretapping targets such as private companies competing
+with government-owned companies, civil rights groups and lawyers,
+opposition political parties, and dissidents. 
+
+FreeS/WAN provides privacy for Internet packets using the proposed
+standard Internet Protocol Security (IPSEC) protocols.  FreeS/WAN
+negotiates strong keys using Diffie-Hellman key agreement with 1024-bit
+keys, and encrypts each packet with 168-bit Triple-DES (3DES).  A modern
+$500 PC can set up a tunnel in less than a second, and can encrypt
+6 megabits of packets per second, easily handling the whole available
+bandwidth at the vast majority of Internet sites.  In preliminary testing,
+FreeS/WAN interoperated with 3DES IPSEC products from OpenBSD, PGP, SSH,
+Cisco, Raptor, and Xedia.  Since FreeS/WAN is distributed as source code,
+its innards are open to review by outside experts and sophisticated users,
+reducing the chance of undetected bugs or hidden security compromises.
+
+The software has been in development for several years.  It has been
+funded by several philanthropists interested in increased privacy on
+the Internet, including John Gilmore, co-founder of the Electronic
+Frontier Foundation, a leading online civil rights group.
+
+Press contacts:
+Hugh Daniel,   +1 408 353 8124, hugh@toad.com
+Henry Spencer, +1 416 690 6561, henry@spsystems.net
+
+* FreeS/WAN derives its name from S/WAN, which is a trademark of RSA Data
+  Security, Inc; used by permission.</PRE>
+<HR>
+<H1><A name="ipsec.detail">The IPsec protocols</A></H1>
+<P>This section provides information on the IPsec protocols which
+ FreeS/WAN implements. For more detail, see the<A href="rfc.html"> RFCs</A>
+.</P>
+<P>The basic idea of IPsec is to provide security functions,<A href="#authentication">
+ authentication</A> and<A href="#encryption"> encryption</A>, at the IP
+ (Internet Protocol) level. This requires a higher-level protocol (IKE)
+ to set things up for the IP-level services (ESP and AH).</P>
+<H2><A NAME="27_1">Protocols and phases</A></H2>
+<P>Three protocols are used in an IPsec implementation:</P>
+<DL>
+<DT>ESP, Encapsulating Security Payload</DT>
+<DD>Encrypts and/or authenticates data</DD>
+<DT>AH, Authentication Header</DT>
+<DD>Provides a packet authentication service</DD>
+<DT>IKE, Internet Key Exchange</DT>
+<DD>Negotiates connection parameters, including keys, for the other two</DD>
+</DL>
+<P>The term &quot;IPsec&quot; (also written as IPSEC) is slightly ambiguous. In
+ some contexts, it includes all three of the above but in other contexts
+ it refers only to AH and ESP.</P>
+<P>There is more detail below, but a quick summary of how the whole
+ thing works is:</P>
+<DL>
+<DT>Phase one IKE (main mode exchange)</DT>
+<DD>sets up a keying channel (ISAKMP SA) between the two gateways</DD>
+<DT>Phase two IKE (quick mode exchange)</DT>
+<DD>sets up data channels (IPsec SAs)</DD>
+<DT>IPsec proper</DT>
+<DD>exchanges data using AH or ESP</DD>
+</DL>
+<P>Both phases of IKE are repeated periodically to automate re-keying.</P>
+<H2><A name="others">Applying IPsec</A></H2>
+<P>Authentication and encryption functions for network data can, of
+ course, be provided at other levels. Many security protocols work at
+ levels above IP.</P>
+<UL>
+<LI><A href="#PGP">PGP</A> encrypts and authenticates mail messages</LI>
+<LI><A href="#ssh">SSH</A> authenticates remote logins and then encrypts
+ the session</LI>
+<LI><A href="#SSL">SSL</A> or<A href="#TLS"> TLS</A> provides security
+ at the sockets layer, e.g. for secure web browsing</LI>
+</UL>
+<P>and so on. Other techniques work at levels below IP. For example,
+ data on a communications circuit or an entire network can be encrypted
+ by specialised hardware. This is common practice in high-security
+ applications.</P>
+<H3><A name="advantages">Advantages of IPsec</A></H3>
+<P>There are, however, advantages to doing it at the IP level instead
+ of, or as well as, at other levels.</P>
+<P>IPsec is the<STRONG> most general way to provide these services for
+ the Internet</STRONG>.</P>
+<UL>
+<LI>Higher-level services protect a<EM> single protocol</EM>; for
+ example PGP protects mail.</LI>
+<LI>Lower level services protect a<EM> single medium</EM>; for example a
+ pair of encryption boxes on the ends of a line make wiretaps on that
+ line useless unless the attacker is capable of breaking the encryption.</LI>
+</UL>
+<P>IPsec, however, can protect<EM> any protocol</EM> running above IP
+ and<EM> any medium</EM> which IP runs over. More to the point, it can
+ protect a mixture of application protocols running over a complex
+ combination of media. This is the normal situation for Internet
+ communication; IPsec is the only general solution.</P>
+<P>IPsec can also provide some security services &quot;in the background&quot;,
+ with<STRONG> no visible impact on users</STRONG>. To use<A href="#PGP">
+ PGP</A> encryption and signatures on mail, for example, the user must
+ at least:</P>
+<UL>
+<LI>remember his or her passphrase,</LI>
+<LI>keep it secure</LI>
+<LI>follow procedures to validate correspondents' keys</LI>
+</UL>
+<P>These systems can be designed so that the burden on users is not
+ onerous, but any system will place some requirements on users. No such
+ system can hope to be secure if users are sloppy about meeting those
+ requirements. The author has seen username and password stuck on
+ terminals with post-it notes in an allegedly secure environment, for
+ example.</P>
+<H3><A name="limitations">Limitations of IPsec</A></H3>
+<P>IPsec is designed to secure IP links between machines. It does that
+ well, but it is important to remember that there are many things it
+ does not do. Some of the important limitations are:</P>
+<DL>
+<DT><A name="depends">IPsec cannot be secure if your system isn't</A></DT>
+<DD>System security on IPsec gateway machines is an essential
+ requirement if IPsec is to function as designed. No system can be
+ trusted if the underlying machine has been subverted. See books on Unix
+ security such as<A href="#practical"> Garfinkel and Spafford</A> or our
+ web references for<A href="#linsec"> Linux security</A> or more general<A
+href="#compsec"> computer security</A>.
+<P>Of course, there is another side to this. IPsec can be a powerful
+ tool for improving system and network security. For example, requiring
+ packet authentication makes various spoofing attacks harder and IPsec
+ tunnels can be extremely useful for secure remote administration of
+ various things.</P>
+</DD>
+<DT><A name="not-end-to-end">IPsec is not end-to-end</A></DT>
+<DD>IPsec cannot provide the same end-to-end security as systems working
+ at higher levels. IPsec encrypts an IP connection between two machines,
+ which is quite a different thing than encrypting messages between users
+ or between applications.
+<P>For example, if you need mail encrypted from the sender's desktop to
+ the recipient's desktop and decryptable only by the recipient, use<A href="#PGP">
+ PGP</A> or another such system. IPsec can encrypt any or all of the
+ links involved -- between the two mail servers, or between either
+ server and its clients. It could even be used to secure a direct IP
+ link from the sender's desktop machine to the recipient's, cutting out
+ any sort of network snoop. What it cannot ensure is end-to-end
+ user-to-user security. If only IPsec is used to secure mail, then
+ anyone with appropriate privileges on any machine where that mail is
+ stored (at either end or on any store-and-forward servers in the path)
+ can read it.</P>
+<P>In another common setup, IPsec encrypts packets at a security gateway
+ machine as they leave the sender's site and decrypts them on arrival at
+ the gateway to the recipient's site. This does provide a useful
+ security service -- only encrypted data is passed over the Internet --
+ but it does not even come close to providing an end-to-end service. In
+ particular, anyone with appropriate privileges on either site's LAN can
+ intercept the message in unencrypted form.</P>
+</DD>
+<DT><A name="notpanacea">IPsec cannot do everything</A></DT>
+<DD>IPsec also cannot provide all the functions of systems working at
+ higher levels of the protocol stack. If you need a document
+ electronically signed by a particular person, then you need his or her<A
+href="#signature"> digital signature</A> and a<A href="#public"> public
+ key cryptosystem</A> to verify it with.
+<P>Note, however, that IPsec authentication of the underlying
+ communication can make various attacks on higher-level protocols more
+ difficult. In particular, authentication prevents<A href="#middle">
+ man-in-the-middle attacks</A>.</P>
+</DD>
+<DT><A name="no_user">IPsec authenticates machines, not users</A></DT>
+<DD>IPsec uses strong authentication mechanisms to control which
+ messages go to which machines, but it does not have the concept of user
+ ID, which is vital to many other security mechansims and policies. This
+ means some care must be taken in fitting the various security
+ mechansims on a network together. For example, if you need to control
+ which users access your database server, you need some non-IPsec
+ mechansim for that. IPsec can control which machines connect to the
+ server, and can ensure that data transfer to those machines is done
+ securely, but that is all. Either the machines themselves must control
+ user access or there must be some form of user authentication to the
+ database, independent of IPsec.</DD>
+<DT><A name="DoS">IPsec does not stop denial of service attacks</A></DT>
+<DD><A href="#DOS">Denial of service</A> attacks aim at causing a system
+ to crash, overload, or become confused so that legitimate users cannot
+ get whatever services the system is supposed to provide. These are
+ quite different from attacks in which the attacker seeks either to use
+ the service himself or to subvert the service into delivering incorrect
+ results.
+<P>IPsec shifts the ground for DoS attacks; the attacks possible against
+ systems using IPsec are different than those that might be used against
+ other systems. It does not, however, eliminate the possibility of such
+ attacks.</P>
+</DD>
+<DT><A name="traffic">IPsec does not stop traffic analysis</A></DT>
+<DD><A href="#traffic">Traffic analysis</A> is the attempt to derive
+ intelligence from messages without regard for their contents. In the
+ case of IPsec, it would mean analysis based on things visible in the
+ unencrypted headers of encrypted packets -- source and destination
+ gateway addresses, packet size, et cetera. Given the resources to
+ acquire such data and some skill in analysing it (both of which any
+ national intelligence agency should have), this can be a very powerful
+ technique.
+<P>IPsec is not designed to defend against this. Partial defenses are
+ certainly possible, and some are<A href="#traffic.resist"> described
+ below</A>, but it is not clear that any complete defense can be
+ provided.</P>
+</DD>
+</DL>
+<H3><A name="uses">IPsec is a general mechanism for securing IP</A></H3>
+<P>While IPsec does not provide all functions of a mail encryption
+ package, it can encrypt your mail. In particular, it can ensure that
+ all mail passing between a pair or a group of sites is encrypted. An
+ attacker looking only at external traffic, without access to anything
+ on or behind the IPsec gateway, cannot read your mail. He or she is
+ stymied by IPsec just as he or she would be by<A href="#PGP"> PGP</A>.</P>
+<P>The advantage is that IPsec can provide the same protection for<STRONG>
+ anything transmitted over IP</STRONG>. In a corporate network example,
+ PGP lets the branch offices exchange secure mail with head office. SSL
+ and SSH allow them to securely view web pages, connect as terminals to
+ machines, and so on. IPsec can support all those applications, plus
+ database queries, file sharing (NFS or Windows), other protocols
+ encapsulated in IP (Netware, Appletalk, ...), phone-over-IP,
+ video-over-IP, ... anything-over-IP. The only limitation is that IP
+ Multicast is not yet supported, though there are Internet Draft
+ documents for that.</P>
+<P>IPsec creates<STRONG> secure tunnels through untrusted networks</STRONG>
+. Sites connected by these tunnels form VPNs,<A href="#VPN"> Virtual
+ Private Networks</A>.</P>
+<P>IPsec gateways can be installed wherever they are required.</P>
+<UL>
+<LI>One organisation might choose to install IPsec only on firewalls
+ between their LANs and the Internet. This would allow them to create a
+ VPN linking several offices. It would provide protection against anyone
+ outside their sites.</LI>
+<LI>Another might install IPsec on departmental servers so everything on
+ the corporate backbone net was encrypted. This would protect messages
+ on that net from everyone except the sending and receiving department.</LI>
+<LI>Another might be less concerned with information secrecy and more
+ with controlling access to certain resources. They might use IPsec
+ packet authentication as part of an access control mechanism, with or
+ without also using the IPsec encryption service.</LI>
+<LI>It is even possible (assuming adequate processing power and an IPsec
+ implementation in each node) to make every machine its own IPsec
+ gateway so that everything on a LAN is encrypted. This protects
+ information from everyone outside the sending and receiving machine.</LI>
+<LI>These techniques can be combined in various ways. One might, for
+ example, require authentication everywhere on a network while using
+ encryption only for a few links.</LI>
+</UL>
+<P>Which of these, or of the many other possible variants, to use is up
+ to you.<STRONG> IPsec provides mechanisms; you provide the policy</STRONG>
+.</P>
+<P><STRONG>No end user action is required</STRONG> for IPsec security to
+ be used; they don't even have to know about it. The site
+ administrators, of course, do have to know about it and to put some
+ effort into making it work. Poor administration can compromise IPsec as
+ badly as the post-it notes mentioned above. It seems reasonable,
+ though, for organisations to hope their system administrators are
+ generally both more security-conscious than end users and more able to
+ follow computer security procedures. If not, at least there are fewer
+ of them to educate or replace.</P>
+<P>IPsec can be, and often should be, used with along with security
+ protocols at other levels. If two sites communicate with each other via
+ the Internet, then IPsec is the obvious way to protect that
+ communication. If two others have a direct link between them, either
+ link encryption or IPsec would make sense. Choose one or use both.
+ Whatever you use at and below the IP level, use other things as
+ required above that level. Whatever you use above the IP level,
+ consider what can be done with IPsec to make attacks on the higher
+ levels harder. For example,<A href="#middle"> man-in-the-middle attacks</A>
+ on various protocols become difficult if authentication at packet level
+ is in use on the potential victims' communication channel.</P>
+<H3><A name="authonly">Using authentication without encryption</A></H3>
+<P>Where appropriate, IPsec can provide authentication without
+ encryption. One might do this, for example:</P>
+<UL>
+<LI>where the data is public but one wants to be sure of getting the
+ right data, for example on some web sites</LI>
+<LI>where encryption is judged unnecessary, for example on some company
+ or department LANs</LI>
+<LI>where strong encryption is provided at link level, below IP</LI>
+<LI>where strong encryption is provided in other protocols, above IP
+<BR> Note that IPsec authentication may make some attacks on those
+ protocols harder.</LI>
+</UL>
+<P>Authentication has lower overheads than encryption.</P>
+<P>The protocols provide four ways to build such connections, using
+ either an AH-only connection or ESP using null encryption, and in
+ either manually or automatically keyed mode. FreeS/WAN supports only
+ one of these, manually keyed AH-only connections, and<STRONG> we do not
+ recommend using that</STRONG>. Our reasons are discussed under<A href="#traffic.resist">
+ Resisting traffic analysis</A> a few sections further along.</P>
+<H3><A name="encnoauth">Encryption without authentication is dangerous</A>
+</H3>
+<P>Originally, the IPsec encryption protocol<A href="#ESP"> ESP</A>
+ didn't do integrity checking. It only did encryption. Steve Bellovin
+ found many ways to attack ESP used without authentication. See his
+ paper<A href="http://www.research.att.com/~smb/papers/badesp.ps">
+ Problem areas for the IP Security Protocols</A>. To make a secure
+ connection, you had to add an<A href="#AH"> AH</A> Authentication
+ Header as well as ESP. Rather than incur the overhead of several layers
+ (and rather than provide an ESP layer that didn't actually protect the
+ traffic), the IPsec working group built integrity and replay checking
+ directly into ESP.</P>
+<P>Today, typical usage is one of:</P>
+<UL>
+<LI>ESP for encryption and authentication</LI>
+<LI>AH for authentication alone</LI>
+</UL>
+<P>Other variants are allowed by the standard, but not much used:</P>
+<DL>
+<DT>ESP encryption without authentication</DT>
+<DD><STRONG>Bellovin has demonstrated fatal flaws in this. Do not use.</STRONG>
+</DD>
+<DT>ESP encryption with AH authentication</DT>
+<DD>This has higher overheads than using the authentication in ESP, and
+ no obvious benefit in most cases. The exception might be a network
+ where AH authentication was widely or universally used. If you're going
+ to do AH to conform with network policy, why authenticate again in the
+ ESP layer?</DD>
+<DT>Authenticate twice, with AH and with ESP</DT>
+<DD>Why? Of course, some folk consider &quot;belt and suspenders&quot; the
+ sensible approach to security. If you're among them, you might use both
+ protocols here. You might also use both to satisfy different parts of a
+ security policy. For example, an organisation might require AH
+ authentication everywhere but two users within the organisation might
+ use ESP as well.</DD>
+<DT>ESP authentication without encryption</DT>
+<DD>The standard allows this, calling it &quot;null encryption&quot;. FreeS/WAN
+ does not support it. We recommend that you use AH instead if
+ authentication is all you require. AH authenticates parts of the IP
+ header, which ESP-null does not do.</DD>
+</DL>
+<P>Some of these variants cannot be used with FreeS/WAN because we do
+ not support ESP-null and do not support automatic keying of AH-only
+ connections.</P>
+<P>There are fairly frequent suggestions that AH be dropped entirely
+ from the IPsec specifications since ESP and null encryption can handle
+ that situation. It is not clear whether this will occur. My guess is
+ that it is unlikely.</P>
+<H3><A name="multilayer">Multiple layers of IPsec processing are
+ possible</A></H3>
+<P>The above describes combinations possible on a single IPsec
+ connection. In a complex network you may have several layers of IPsec
+ in play, with any of the above combinations at each layer.</P>
+<P>For example, a connection from a desktop machine to a database server
+ might require AH authentication. Working with other host, network and
+ database security measures, AH might be just the thing for access
+ control. You might decide not to use ESP encryption on such packets,
+ since it uses resources and might complicate network debugging. Within
+ the site where the server is, then, only AH would be used on those
+ packets.</P>
+<P>Users at another office, however, might have their whole connection
+ (AH headers and all) passing over an IPsec tunnel connecting their
+ office to the one with the database server. Such a tunnel should use
+ ESP encryption and authentication. You need authentication in this
+ layer because without authentication the encryption is vulnerable and
+ the gateway cannot verify the AH authentication. The AH is between
+ client and database server; the gateways aren't party to it.</P>
+<P>In this situation, some packets would get multiple layers of IPsec
+ applied to them, AH on an end-to-end client-to-server basis and ESP
+ from one office's security gateway to the other.</P>
+<H3><A name="traffic.resist">Resisting traffic analysis</A></H3>
+<P><A href="#traffic">Traffic analysis</A> is the attempt to derive
+ useful intelligence from encrypted traffic without breaking the
+ encryption.</P>
+<P>Is your CEO exchanging email with a venture capital firm? With
+ bankruptcy trustees? With an executive recruiting agency? With the
+ holder of some important patents? If an eavesdropper learns about any
+ of those, then he has interesting intelligence on your company, whether
+ or not he can read the messages themselves.</P>
+<P>Even just knowing that there is network traffic between two sites may
+ tell an analyst something useful, especially when combined with
+ whatever other information he or she may have. For example, if you know
+ Company A is having cashflow problems and Company B is looking for
+ aquisitions, then knowing that packets are passing between the two is
+ interesting. It is more interesting if you can tell it is email, and
+ perhaps yet more if you know the sender and recipient.</P>
+<P>Except in the simplest cases, traffic analysis is hard to do well. It
+ requires both considerable resources and considerable analytic skill.
+ However, intelligence agencies of various nations have been doing it
+ for centuries and many of them are likely quite good at it by now.
+ Various commercial organisations, especially those working on &quot;targeted
+ marketing&quot; may also be quite good at analysing certain types of
+ traffic.</P>
+<P>In general, defending against traffic analysis is also difficult.
+ Inventing a really good defense could get you a PhD and some
+ interesting job offers.</P>
+<P>IPsec is not designed to stop traffic analysis and we know of no
+ plausible method of extending it to do so. That said, there are ways to
+ make traffic analysis harder. This section describes them.</P>
+<H4><A name="extra">Using &quot;unnecessary&quot; encryption</A></H4>
+<P>One might choose to use encryption even where it appears unnecessary
+ in order to make analysis more difficult. Consider two offices which
+ pass a small volume of business data between them using IPsec and also
+ transfer large volumes of Usenet news. At first glance, it would seem
+ silly to encrypt the newsfeed, except possibly for any newsgroups that
+ are internal to the company. Why encrypt data that is all publicly
+ available from many sites?</P>
+<P>However, if we encrypt a lot of news and send it down the same
+ connection as our business data, we make<A href="#traffic"> traffic
+ analysis</A> much harder. A snoop cannot now make inferences based on
+ patterns in the volume, direction, sizes, sender, destination, or
+ timing of our business messages. Those messages are hidden in a mass of
+ news messages encapsulated in the same way.</P>
+<P>If we're going to do this we need to ensure that keys change often
+ enough to remain secure even with high volumes and with the adversary
+ able to get plaintext of much of the data. We also need to look at
+ other attacks this might open up. For example, can the adversary use a
+ chosen plaintext attack, deliberately posting news articles which, when
+ we receive and encrypt them, will help break our encryption? Or can he
+ block our business data transmission by flooding us with silly news
+ articles? Or ...</P>
+<P>Also, note that this does not provide complete protection against
+ traffic analysis. A clever adversary might still deduce useful
+ intelligence from statistical analysis (perhaps comparing the input
+ newsfeed to encrypted output, or comparing the streams we send to
+ different branch offices), or by looking for small packets which might
+ indicate establishment of TCP connections, or ...</P>
+<P>As a general rule, though, to improve resistance to traffic analysis,
+ you should<STRONG> encrypt as much traffic as possible, not just as
+ much as seems necessary.</STRONG></P>
+<H4><A name="multi-encrypt">Using multiple encryption</A></H4>
+<P>This also applies to using multiple layers of encryption. If you have
+ an IPsec tunnel between two branch offices, it might appear silly to
+ send<A href="#PGP"> PGP</A>-encrypted email through that tunnel.
+ However, if you suspect someone is snooping your traffic, then it does
+ make sense:</P>
+<UL>
+<LI>it protects the mail headers; they cannot even see who is mailing
+ who</LI>
+<LI>it protects against user bungles or software malfunctions that
+ accidentally send messages in the clear</LI>
+<LI>it makes any attack on the mail encryption much harder; they have to
+ break IPsec or break into your network before they can start on the
+ mail encryption</LI>
+</UL>
+<P>Similar arguments apply for<A href="#SSL"> SSL</A>-encrypted web
+ traffic or<A href="#ssh"> SSH</A>-encrypted remote login sessions, even
+ for end-to-end IPsec tunnels between systems in the two offices.</P>
+<H4><A name="fewer">Using fewer tunnels</A></H4>
+<P>It may also help to use fewer tunnels. For example, if all you
+ actually need encrypted is connections between:</P>
+<UL>
+<LI>mail servers at branch and head offices</LI>
+<LI>a few branch office users and the head office database server</LI>
+</UL>
+<P>You might build one tunnel per mail server and one per remote
+ database user, restricting traffic to those applications. This gives
+ the traffic analyst some information, however. He or she can
+ distinguish the tunnels by looking at information in the ESP header
+ and, given that distinction and the patterns of tunnel usage, might be
+ able to figure out something useful. Perhaps not, but why take the
+ risk?</P>
+<P>We suggest instead that you build one tunnel per branch office,
+ encrypting everything passing from head office to branches. This has a
+ number of advantages:</P>
+<UL>
+<LI>it is easier to build and administer</LI>
+<LI>it resists traffic analysis somewhat better</LI>
+<LI>it provides security for whatever you forgot. For example, if some
+ user at a remote office browses proprietary company data on some head
+ office web page (that the security people may not even know about!),
+ then that data is encrypted before it reaches the Internet.</LI>
+</UL>
+<P>Of course you might also want to add additional tunnels. For example,
+ if some of the database data is confidential and should not be exposed
+ even within the company, then you need protection from the user's
+ desktop to the database server. We suggest you do that in whatever way
+ seems appropriate -- IPsec, SSH or SSL might fit -- but, whatever you
+ choose, pass it between locations via a gateway-to-gateway IPsec tunnel
+ to provide some resistance to traffic analysis.</P>
+<H2><A name="primitives">Cryptographic components</A></H2>
+<P>IPsec combines a number of cryptographic techniques, all of them
+ well-known and well-analyzed. The overall design approach was
+ conservative; no new or poorly-understood components were included.</P>
+<P>This section gives a brief overview of each technique. It is intended
+ only as an introduction. There is more information, and links to
+ related topics, in our<A href="glossary.html"> glossary</A>. See also
+ our<A href="biblio.html"> bibliography</A> and cryptography<A href="#crypto.link">
+ web links</A>.</P>
+<H3><A name="block.cipher">Block ciphers</A></H3>
+<P>The<A href="#encryption"> encryption</A> in the<A href="#ESP"> ESP</A>
+ encapsulation protocol is done with a<A href="#block"> block cipher</A>
+.</P>
+<P>We do not implement<A href="#DES"> single DES</A>. It is<A href="#desnotsecure">
+ insecure</A>. Our default, and currently only, block cipher is<A href="#3DES">
+ triple DES</A>.</P>
+<P>The<A href="#rijndael"> Rijndael</A> block cipher has won the<A href="#AES">
+ AES</A> competition to choose a relacement for DES. It will almost
+ certainly be added to FreeS/WAN and to other IPsec implementations.<A href="#patch">
+ Patches</A> are already available.</P>
+<H3><A name="hash.ipsec">Hash functions</A></H3>
+<H4><A name="hmac.ipsec">The HMAC construct</A></H4>
+<P>IPsec packet authentication is done with the<A href="#HMAC"> HMAC</A>
+ construct. This is not just a hash of the packet data, but a more
+ complex operation which uses both a hashing algorithm and a key. It
+ therefore does more than a simple hash would. A simple hash would only
+ tell you that the packet data was not changed in transit, or that
+ whoever changed it also regenerated the hash. An HMAC also tells you
+ that the sender knew the HMAC key.</P>
+<P>For IPsec HMAC, the output of the hash algorithm is truncated to 96
+ bits. This saves some space in the packets. More important, it prevents
+ an attacker from seeing all the hash output bits and perhaps creating
+ some sort of attack based on that knowledge.</P>
+<H4><A NAME="27_3_2_2">Choice of hash algorithm</A></H4>
+<P>The IPsec RFCs require two hash algorithms --<A href="#MD5"> MD5</A>
+ and<A href="#SHA"> SHA-1</A> -- both of which FreeS/WAN implements.</P>
+<P>Various other algorithms -- such as RIPEMD and Tiger -- are listed in
+ the RFCs as optional. None of these are in the FreeS/WAN distribution,
+ or are likely to be added, although user<A href="#patch"> patches</A>
+ exist for several of them.</P>
+<P>Additional hash algorithms --<A href="#SHA-256"> SHA-256, SHA-384 and
+ SHA-512</A> -- may be required to give hash strength matching the
+ strength of<A href="#AES"> AES</A>. These are likely to be added to
+ FreeS/WAN along with AES.</P>
+<H3><A name="DH.keying">Diffie-Hellman key agreement</A></H3>
+<P>The<A href="#DH"> Diffie-Hellman</A> key agreement protocol allows
+ two parties (A and B or<A href="#alicebob"> Alice and Bob</A>) to agree
+ on a key in such a way that an eavesdropper who intercepts the entire
+ conversation cannot learn the key.</P>
+<P>The protocol is based on the<A href="#dlog"> discrete logarithm</A>
+ problem and is therefore thought to be secure. Mathematicians have been
+ working on that problem for years and seem no closer to a solution,
+ though there is no proof that an efficient solution is impossible.</P>
+<H3><A name="RSA.auth">RSA authentication</A></H3>
+<P>The<A href="#RSA"> RSA</A> algorithm (named for its inventors --
+ Rivest, Shamir and Adleman) is a very widely used<A href="glossary.html#">
+ public key</A> cryptographic technique. It is used in IPsec as one
+ method of authenticating gateways for Diffie-Hellman key negotiation.</P>
+<H2><A name="structure">Structure of IPsec</A></H2>
+<P>There are three protocols used in an IPsec implementation:</P>
+<DL>
+<DT>ESP, Encapsulating Security Payload</DT>
+<DD>Encrypts and/or authenticates data</DD>
+<DT>AH, Authentication Header</DT>
+<DD>Provides a packet authentication service</DD>
+<DT>IKE, Internet Key Exchange</DT>
+<DD>Negotiates connection parameters, including keys, for the other two</DD>
+</DL>
+<P>The term &quot;IPsec&quot; is slightly ambiguous. In some contexts, it includes
+ all three of the above but in other contexts it refers only to AH and
+ ESP.</P>
+<H3><A name="IKE.ipsec">IKE (Internet Key Exchange)</A></H3>
+<P>The IKE protocol sets up IPsec (ESP or AH) connections after
+ negotiating appropriate parameters (algorithms to be used, keys,
+ connection lifetimes) for them. This is done by exchanging packets on
+ UDP port 500 between the two gateways.</P>
+<P>IKE (RFC 2409) was the outcome of a long, complex process in which
+ quite a number of protocols were proposed and debated. Oversimplifying
+ mildly, IKE combines:</P>
+<DL>
+<DT>ISAKMP (RFC 2408)</DT>
+<DD>The<STRONG> I</STRONG>nternet<STRONG> S</STRONG>ecurity<STRONG> A</STRONG>
+ssociation and<STRONG> K</STRONG>ey<STRONG> M</STRONG>anagement<STRONG>
+ P</STRONG>rotocol manages negotiation of connections and defines<A href="#SA">
+ SA</A>s (Security Associations) as a means of describing connection
+ properties.</DD>
+<DT>IPsec DOI for ISAKMP (RFC 2407)</DT>
+<DD>A<STRONG> D</STRONG>omain<STRONG> O</STRONG>f<STRONG> I</STRONG>
+nterpretation fills in the details necessary to turn the rather abstract
+ ISAKMP protocol into a more tightly specified protocol, so it becomes
+ applicable in a particular domain.</DD>
+<DT>Oakley key determination protocol (RFC 2412)</DT>
+<DD>Oakley creates keys using the<A href="#DH"> Diffie-Hellman</A> key
+ agreement protocol.</DD>
+</DL>
+<P>For all the details, you would need to read the four<A href="rfc.html">
+ RFCs</A> just mentioned (over 200 pages) and a number of others. We
+ give a summary below, but it is far from complete.</P>
+<H4><A name="phases">Phases of IKE</A></H4>
+<P>IKE negotiations have two phases.</P>
+<DL>
+<DT>Phase one</DT>
+<DD>The two gateways negotiate and set up a two-way ISAKMP SA which they
+ can then use to handle phase two negotiations. One such SA between a
+ pair of gateways can handle negotiations for multiple tunnels.</DD>
+<DT>Phase two</DT>
+<DD>Using the ISAKMP SA, the gateways negotiate IPsec (ESP and/or AH)
+ SAs as required. IPsec SAs are unidirectional (a different key is used
+ in each direction) and are always negotiated in pairs to handle two-way
+ traffic. There may be more than one pair defined between two gateways.</DD>
+</DL>
+<P>Both of these phases use the UDP protocol and port 500 for their
+ negotiations.</P>
+<P>After both IKE phases are complete, you have IPsec SAs to carry your
+ encrypted data. These use the ESP or AH protocols. These protocols do
+ not have ports. Ports apply only to UDP or TCP.</P>
+<P>The IKE protocol is designed to be extremely flexible. Among the
+ things that can be negotiated (separately for each SA) are:</P>
+<UL>
+<LI>SA lifetime before rekeying</LI>
+<LI>encryption algorithm used. We currently support only<A href="#3DES">
+ triple DES</A>. Single DES is<A href="#desnotsecure"> insecure</A>. The
+ RFCs say you MUST do DES, SHOULD do 3DES and MAY do various others. We
+ do not do any of the others.</LI>
+<LI>authentication algorithms. We support<A href="#MD5"> MD5</A> and<A href="#SHA">
+ SHA</A>. These are the two the RFCs require.</LI>
+<LI>choice of group for<A href="#DH"> Diffie-Hellman</A> key agreement.
+ We currently support Groups 2 and 5 (which are defined modulo primes of
+ various lengths) and do not support Group 1 (defined modulo a shorter
+ prime, and therefore cryptographically weak) or groups 3 and 4 (defined
+ using elliptic curves). The RFCs require only Group 1.</LI>
+</UL>
+<P>The protocol also allows implementations to add their own encryption
+ algorithms, authentication algorithms or Diffie-Hellman groups. We do
+ not support any such extensions, but there are some<A href="#patch">
+ patches</A> that do.</P>
+<P>There are a number of complications:</P>
+<UL>
+<LI>The gateways must be able to authenticate each other's identities
+ before they can create a secure connection. This host authentication is
+ part of phase one negotiations, and is a required prerequisite for
+ packet authentication used later. Host authentication can be done in a
+ variety of ways. Those supported by FreeS/WAN are discussed in our<A href="#auto-auth">
+ advanced configuration</A> document.</LI>
+<LI>Phase one can be done in two ways.
+<UL>
+<LI>Main Mode is required by the RFCs and supported in FreeS/WAN. It
+ uses a 6-packet exzchange.</LI>
+<LI>Aggressive Mode is somewhat faster (only 3 packets) but reveals more
+ to an eavesdropper. This is optional in the RFCs, not currently
+ supported by FreeS/WAN, and not likely to be.</LI>
+</UL>
+</LI>
+<LI>A new group exchange may take place after phase one but before phase
+ two, defining an additional group for use in the<A href="#DH">
+ Diffie-Hellman</A> key agreement part of phase two. FreeS/WAN does not
+ currently support this.</LI>
+<LI>Phase two always uses Quick Mode, but there are two variants of
+ that:
+<UL>
+<LI>One variant provides<A href="#PFS"> Perfect Forward Secrecy (PFS)</A>
+. An attacker that obtains your long-term host authentication key does
+ not immediately get any of your short-term packet encryption of packet
+ authentication keys. He must conduct another successful attack each
+ time you rekey to get the short-term keys. Having some short-term keys
+ does not help him learn others. In particular, breaking your system
+ today does not let him read messages he archived yestarday, assuming
+ you've changed short-term keys in the meanwhile. We enable PFS as the
+ default.</LI>
+<LI>The other variant disables PFS and is therefore slightly faster. We
+ do not recommend this since it is less secure, but FreeS/WAN does
+ support it. You can enable it with a<VAR> pfs=no</VAR> statement in<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A>.</LI>
+<LI>The protocol provides no way to negotiate which variant will be
+ used. If one gateway is set for PFS and the other is not, the
+ negotiation fails. This has proved a fairly common source of
+ interoperation problems.</LI>
+</UL>
+</LI>
+<LI>Several types of notification message may be sent by either side
+ during either phase, or later. FreeS/WAN does not currently support
+ these, but they are a likely addition in future releases.</LI>
+<LI>There is a commit flag which may optionally be set on some messages.
+ The<A href="http://www.lounge.org/ike_doi_errata.html"> errata</A> page
+ for the RFCs includes two changes related to this, one to clarify the
+ description of its use and one to block a<A href="#DOS"> denial of
+ service</A> attack which uses it. We currently do not implement this
+ feature.</LI>
+</UL>
+<P>These complications can of course lead to problems, particularly when
+ two different implementations attempt to interoperate. For example, we
+ have seen problems such as:</P>
+<UL>
+<LI>Some implementations (often products crippled by<A href="#exlaw">
+ export laws</A>) have the insecure DES algorithm as their only
+ supported encryption method. Other parts of our documentation discuss
+ the<A href="#desnotsecure"> reasons we do not implement single DES</A>,
+ and<A href="interop.html#noDES"> how to cope with crippled products</A>
+.</LI>
+<LI>Windows 2000 IPsec tries to negotiate using Aggressive Mode, which
+ we don't support. Later on, it uses the commit bit, which we also don't
+ support.</LI>
+<LI>Various implementations disable PFS by default, and therefore will
+ not talk to FreeS/WAN until you either turn on PFS on their end or turn
+ it off in FreeS/WAN with a<VAR> pfs=no</VAR> entry in the connection
+ description.</LI>
+<LI>FreeS/WAN's interaction with PGPnet is complicated by their use of
+ notification messages we do not yet support.</LI>
+</UL>
+<P>Despite this, we do interoperate successfully with many
+ implementations, including both Windows 2000 and PGPnet. Details are in
+ our<A href="interop.html"> interoperability</A> document.</P>
+<H4><A name="sequence">Sequence of messages in IKE</A></H4>
+<P>Each phase (see<A href="#phases"> previous section</A>)of IKE
+ involves a series of messages. In Pluto error messages, these are
+ abbreviated using:</P>
+<DL>
+<DT>M</DT>
+<DD><STRONG>M</STRONG>ain mode, settting up the keying channel (ISAKMP
+ SA)</DD>
+<DT>Q</DT>
+<DD><STRONG>Q</STRONG>uick mode, setting up the data channel (IPsec SA)</DD>
+<DT>I</DT>
+<DD><STRONG>I</STRONG>nitiator, the machine that starts the negotiation</DD>
+<DT>R</DT>
+<DD><STRONG>R</STRONG>esponder</DD>
+</DL>
+<P>For example, the six messages of a main mode negotiation, in
+ sequence, are labelled:</P>
+<PRE>       MI1 ----------&gt;
+           &lt;---------- MR1
+       MI2 ----------&gt; 
+           &lt;---------- MR2
+       MI3 ----------&gt;
+           &lt;---------- MR3</PRE>
+<H4><A name="struct.exchange">Structure of IKE messages</A></H4>
+<P>Here is our Pluto developer explaining some of this on the mailing
+ list:</P>
+<PRE>When one IKE system (for example, Pluto) is negotiating with another
+to create an SA, the Initiator proposes a bunch of choices and the
+Responder replies with one that it has selected.
+
+The structure of the choices is fairly complicated.  An SA payload
+contains a list of lists of &quot;Proposals&quot;.  The outer list is a set of
+choices: the selection must be from one element of this list.
+
+Each of these elements is a list of Proposals.  A selection must be
+made from each of the elements of the inner list.  In other words,
+*all* of them apply (that is how, for example, both AH and ESP can
+apply at once).
+
+Within each of these Proposals is a list of Transforms.  For each
+Proposal selected, one Transform must be selected (in other words,
+each Proposal provides a choice of Transforms).
+
+Each Transform is made up of a list of Attributes describing, well,
+attributes.  Such as lifetime of the SA.  Such as algorithm to be
+used.  All the Attributes apply to a Transform.
+
+You will have noticed a pattern here: layers alternate between being
+disjunctions (&quot;or&quot;) and conjunctions (&quot;and&quot;).
+
+For Phase 1 / Main Mode (negotiating an ISAKMP SA), this structure is
+cut back.  There must be exactly one Proposal.  So this degenerates to
+a list of Transforms, one of which must be chosen.</PRE>
+<H3><A name="services">IPsec Services, AH and ESP</A></H3>
+<P>IPsec offers two services,<A href="#authentication"> authentication</A>
+ and<A href="#encryption"> encryption</A>. These can be used separately
+ but are often used together.</P>
+<DL>
+<DT>Authentication</DT>
+<DD>Packet-level authentication allows you to be confident that a packet
+ came from a particular machine and that its contents were not altered
+ en route to you. No attempt is made to conceal or protect the contents,
+ only to assure their integrity. Packet authentication can be provided
+ separately using an<A href="#AH"> Authentication Header</A>, described
+ just below, or it can be included as part of the<A href="#ESP"> ESP</A>
+ (Encapsulated Security Payload) service, described in the following
+ section. That service offers encryption as well as authentication. In
+ either case, the<A href="#HMAC"> HMAC</A> construct is used as the
+ authentication mechanism.
+<P>There is a separate authentication operation at the IKE level, in
+ which each gateway authenticates the other. This can be done in a
+ variety of ways.</P>
+</DD>
+<DT>Encryption</DT>
+<DD>Encryption allows you to conceal the contents of a message from
+ eavesdroppers.
+<P>In IPsec this is done using a<A href="#block"> block cipher</A>
+ (normally<A href="#3DES"> Triple DES</A> for Linux). In the most used
+ setup, keys are automatically negotiated, and periodically
+ re-negotiated, using the<A href="#IKE"> IKE</A> (Internet Key Exchange)
+ protocol. In Linux FreeS/WAN this is handled by the Pluto Daemon.</P>
+<P>The IPsec protocol offering encryption is<A href="#ESP"> ESP</A>,
+ Encapsulated Security Payload. It can also include a packet
+ authentication service.</P>
+</DD>
+</DL>
+<P>Note that<STRONG> encryption should always be used with some packet
+ authentication service</STRONG>. Unauthenticated encryption is
+ vulnerable to<A href="#middle"> man-in-the-middle attacks</A>. Also
+ note that encryption does not prevent<A href="#traffic"> traffic
+ analysis</A>.</P>
+<H3><A name="AH.ipsec">The Authentication Header (AH)</A></H3>
+<P>Packet authentication can be provided separately from encryption by
+ adding an authentication header (AH) after the IP header but before the
+ other headers on the packet. This is the subject of this section.
+ Details are in RFC 2402.</P>
+<P>Each of the several headers on a packet header contains a &quot;next
+ protocol&quot; field telling the system what header to look for next. IP
+ headers generally have either TCP or UDP in this field. When IPsec
+ authentication is used, the packet IP header has AH in this field,
+ saying that an Authentication Header comes next. The AH header then has
+ the next header type -- usually TCP, UDP or encapsulated IP.</P>
+<P>IPsec packet authentication can be added in transport mode, as a
+ modification of standard IP transport. This is shown in this diagram
+ from the RFC:</P>
+<PRE>                  BEFORE APPLYING AH
+            ----------------------------
+      IPv4  |orig IP hdr  |     |      |
+            |(any options)| TCP | Data |
+            ----------------------------
+
+                  AFTER APPLYING AH
+            ---------------------------------
+      IPv4  |orig IP hdr  |    |     |      |
+            |(any options)| AH | TCP | Data |
+            ---------------------------------
+            ||
+                 except for mutable fields</PRE>
+<P>Athentication can also be used in tunnel mode, encapsulating the
+ underlying IP packet beneath AH and an additional IP header.</P>
+<PRE>                         ||
+IPv4  | new IP hdr* |    | orig IP hdr*  |    |      |
+      |(any options)| AH | (any options) |TCP | Data |
+      ------------------------------------------------
+      ||
+      |           in the new IP hdr                  |</PRE>
+<P>This would normally be used in a gateway-to-gateway tunnel. The
+ receiving gateway then strips the outer IP header and the AH header and
+ forwards the inner IP packet.</P>
+<P>The mutable fields referred to are things like the time-to-live field
+ in the IP header. These cannot be included in authentication
+ calculations because they change as the packet travels.</P>
+<H4><A name="keyed">Keyed MD5 and Keyed SHA</A></H4>
+<P>The actual authentication data in the header is typically 96 bits and
+ depends both on a secret shared between sender and receiver and on
+ every byte of the data being authenticated. The technique used is<A href="#HMAC">
+ HMAC</A>, defined in RFC 2104.</P>
+<P>The algorithms involved are the<A href="#MD5"> MD5</A> Message Digest
+ Algorithm or<A href="#SHA"> SHA</A>, the Secure Hash Algorithm. For
+ details on their use in this application, see RFCs 2403 and 2404
+ respectively.</P>
+<P>For descriptions of the algorithms themselves, see RFC 1321 for MD5
+ and<A href="#FIPS"> FIPS</A> (Federal Information Processing Standard)
+ number 186 from<A href="#NIST"> NIST</A>, the US National Institute of
+ Standards and Technology for SHA.<A href="#schneier"><CITE> Applied
+ Cryptography</CITE></A> covers both in some detail, MD5 starting on
+ page 436 and SHA on 442.</P>
+<P>These algorithms are intended to make it nearly impossible for anyone
+ to alter the authenticated data in transit. The sender calculates a
+ digest or hash value from that data and includes the result in the
+ authentication header. The recipient does the same calculation and
+ compares results. For unchanged data, the results will be identical.
+ The hash algorithms are designed to make it extremely difficult to
+ change the data in any way and still get the correct hash.</P>
+<P>Since the shared secret key is also used in both calculations, an
+ interceptor cannot simply alter the authenticated data and change the
+ hash value to match. Without the key, he or she (or even the dreaded
+ They) cannot produce a usable hash.</P>
+<H4><A name="sequence">Sequence numbers</A></H4>
+<P>The authentication header includes a sequence number field which the
+ sender is required to increment for each packet. The receiver can
+ ignore it or use it to check that packets are indeed arriving in the
+ expected sequence.</P>
+<P>This provides partial protection against<A href="#replay"> replay
+ attacks</A> in which an attacker resends intercepted packets in an
+ effort to confuse or subvert the receiver. Complete protection is not
+ possible since it is necessary to handle legitmate packets which are
+ lost, duplicated, or delivered out of order, but use of sequence
+ numbers makes the attack much more difficult.</P>
+<P>The RFCs require that sequence numbers never cycle, that a new key
+ always be negotiated before the sequence number reaches 2^32-1. This
+ protects both against replays attacks using packets from a previous
+ cyclce and against<A href="#birthday"> birthday attacks</A> on the the
+ packet authentication algorithm.</P>
+<P>In Linux FreeS/WAN, the sequence number is ignored for manually keyed
+ connections and checked for automatically keyed ones. In manual mode,
+ there is no way to negotiate a new key, or to recover from a sequence
+ number problem, so we don't use sequence numbers.</P>
+<H3><A name="ESP.ipsec">Encapsulated Security Payload (ESP)</A></H3>
+<P>The ESP protocol is defined in RFC 2406. It provides one or both of
+ encryption and packet authentication. It may be used with or without AH
+ packet authentication.</P>
+<P>Note that<STRONG> some form of packet authentication should<EM>
+ always</EM> be used whenever data is encrypted</STRONG>. Without
+ authentication, the encryption is vulnerable to active attacks which
+ may allow an enemy to break the encryption. ESP should<STRONG> always</STRONG>
+ either include its own authentication or be used with AH
+ authentication.</P>
+<P>The RFCs require support for only two mandatory encryption algorithms
+ --<A href="#DES"> DES</A>, and null encryption -- and for two
+ authentication methods -- keyed MD5 and keyed SHA. Implementers may
+ choose to support additional algorithms in either category.</P>
+<P>The authentication algorithms are the same ones used in the IPsec<A href="#AH">
+ authentication header</A>.</P>
+<P>We do not implement single DES since<A href="#desnotsecure"> DES is
+ insecure</A>. Instead we provide<A href="#3DES"> triple DES or 3DES</A>
+. This is currently the only encryption algorithm supported.</P>
+<P>We do not implement null encryption since it is obviously insecure.</P>
+<H2><A name="modes">IPsec modes</A></H2>
+<P>IPsec can connect in two modes. Transport mode is a host-to-host
+ connection involving only two machines. In tunnel mode, the IPsec
+ machines act as gateways and trafiic for any number of client machines
+ may be carried.</P>
+<H3><A name="tunnel.ipsec">Tunnel mode</A></H3>
+<P>Security gateways are required to support tunnel mode connections. In
+ this mode the gateways provide tunnels for use by client machines
+ behind the gateways. The client machines need not do any IPsec
+ processing; all they have to do is route things to gateways.</P>
+<H3><A name="transport.ipsec">Transport mode</A></H3>
+<P>Host machines (as opposed to security gateways) with IPsec
+ implementations must also support transport mode. In this mode, the
+ host does its own IPsec processing and routes some packets via IPsec.</P>
+<H2><A name="parts">FreeS/WAN parts</A></H2>
+<H3><A name="KLIPS.ipsec">KLIPS: Kernel IPsec Support</A></H3>
+<P>KLIPS is<STRONG> K</STRONG>erne<STRONG>L</STRONG><STRONG> IP</STRONG>
+SEC<STRONG> S</STRONG>upport, the modifications necessary to support
+ IPsec within the Linux kernel. KILPS does all the actual IPsec
+ packet-handling, including</P>
+<UL>
+<LI>encryption</LI>
+<LI>packet authentication calculations</LI>
+<LI>creation of ESP and AH headers for outgoing packets</LI>
+<LI>interpretation of those headers on incoming packets</LI>
+</UL>
+<P>KLIPS also checks all non-IPsec packets to ensure they are not
+ bypassing IPsec security policies.</P>
+<H3><A name="Pluto.ipsec">The Pluto daemon</A></H3>
+<P><A href="manpage.d/ipsec_pluto.8.html">Pluto(8)</A> is a daemon which
+ implements the IKE protocol. It</P>
+<UL>
+<LI>handles all the Phase one ISAKMP SAs</LI>
+<LI>performs host authentication and negotiates with other gateways</LI>
+<LI>creates IPsec SAs and passes the data required to run them to KLIPS</LI>
+<LI>adjust routing and firewall setup to meet IPsec requirements. See
+ our<A href="firewall.html"> IPsec and firewalling</A> document for
+ details.</LI>
+</UL>
+<P>Pluto is controlled mainly by the<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A> configuration file.</P>
+<H3><A name="command">The ipsec(8) command</A></H3>
+<P>The<A href="manpage.d/ipsec.8.html"> ipsec(8)</A> command is a front
+ end shellscript that allows control over IPsec activity.</P>
+<H3><A name="ipsec.conf">Linux FreeS/WAN configuration file</A></H3>
+<P>The configuration file for Linux FreeS/WAN is</P>
+<PRE>        /etc/ipsec.conf</PRE>
+<P>For details see the<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A> manual page .</P>
+<H2><A name="key">Key management</A></H2>
+<P>There are several ways IPsec can manage keys. Not all are implemented
+ in Linux FreeS/WAN.</P>
+<H3><A name="current">Currently Implemented Methods</A></H3>
+<H4><A name="manual">Manual keying</A></H4>
+<P>IPsec allows keys to be manually set. In Linux FreeS/WAN, such keys
+ are stored with the connection definitions in /etc/ipsec.conf.</P>
+<P><A href="#manual">Manual keying</A> is useful for debugging since it
+ allows you to test the<A href="#KLIPS"> KLIPS</A> kernel IPsec code
+ without the<A href="#Pluto"> Pluto</A> daemon doing key negotiation.</P>
+<P>In general, however, automatic keying is preferred because it is more
+ secure.</P>
+<H4><A name="auto">Automatic keying</A></H4>
+<P>In automatic keying, the<A href="#Pluto"> Pluto</A> daemon negotiates
+ keys using the<A href="#IKE"> IKE</A> Internet Key Exchange protocol.
+ Connections are automatically re-keyed periodically.</P>
+<P>This is considerably more secure than manual keying. In either case
+ an attacker who acquires a key can read every message encrypted with
+ that key, but automatic keys can be changed every few hours or even
+ every few minutes without breaking the connection or requiring
+ intervention by the system administrators. Manual keys can only be
+ changed manually; you need to shut down the connection and have the two
+ admins make changes. Moreover, they have to communicate the new keys
+ securely, perhaps with<A href="#PGP"> PGP</A> or<A href="#ssh"> SSH</A>
+. This may be possible in some cases, but as a general solution it is
+ expensive, bothersome and unreliable. Far better to let<A href="#Pluto">
+ Pluto</A> handle these chores; no doubt the administrators have enough
+ to do.</P>
+<P>Also, automatic keying is inherently more secure against an attacker
+ who manages to subvert your gateway system. If manual keying is in use
+ and an adversary acquires root privilege on your gateway, he reads your
+ keys from /etc/ipsec.conf and then reads all messages encrypted with
+ those keys.</P>
+<P>If automatic keying is used, an adversary with the same privileges
+ can read /etc/ipsec.secrets, but this does not contain any keys, only
+ the secrets used to authenticate key exchanges. Having an adversary
+ able to authenticate your key exchanges need not worry you overmuch.
+ Just having the secrets does not give him any keys. You are still
+ secure against<A href="#passive"> passive</A> attacks. This property of
+ automatic keying is called<A href="#PFS"> perfect forward secrecy</A>,
+ abbreviated PFS.</P>
+<P>Unfortunately, having the secrets does allow an<A href="#active">
+ active attack</A>, specifically a<A href="#middle"> man-in-the-middle</A>
+ attack. Losing these secrets to an attacker may not be quite as
+ disastrous as losing the actual keys, but it is<EM> still a serious
+ security breach</EM>. These secrets should be guarded as carefully as
+ keys.</P>
+<H3><A name="notyet">Methods not yet implemented</A></H3>
+<H4><A name="noauth">Unauthenticated key exchange</A></H4>
+<P>It would be possible to exchange keys without authenticating the
+ players. This would support<A href="#carpediem"> opportunistic
+ encryption</A> -- allowing any two systems to encrypt their
+ communications without requiring a shared PKI or a previously
+ negotiated secret -- and would be secure against<A href="#passive">
+ passive attacks</A>. It would, however, be highly vulnerable to active<A
+href="#middle"> man-in-the-middle</A> attacks. RFC 2408 therefore
+ specifies that all<A href="#ISAKMP"> ISAKMP</A> key management
+ interactions<EM> must</EM> be authenticated.</P>
+<P>There is room for debate here. Should we provide immediate security
+ against<A href="#passive"> passive attacks</A> and encourage widespread
+ use of encryption, at the expense of risking the more difficult<A href="#active">
+ active attacks</A>? Or should we wait until we can implement a solution
+ that can both be widespread and offer security against active attacks?</P>
+<P>So far, we have chosen the second course, complying with the RFCs and
+ waiting for secure DNS (see<A href="#DNS"> below</A>) so that we can do<A
+href="#carpediem"> opportunistic encryption</A> right.</P>
+<H4><A name="DNS">Key exchange using DNS</A></H4>
+<P>The IPsec RFCs allow key exchange based on authentication services
+ provided by<A href="#SDNS"> Secure DNS</A>. Once Secure DNS service
+ becomes widely available, we expect to make this the<EM> primary key
+ management method for Linux FreeS/WAN</EM>. It is the best way we know
+ of to support<A href="#carpediem"> opportunistic encryption</A>,
+ allowing two systems without a common PKI or previous negotiation to
+ secure their communication.</P>
+<P>We currently have code to acquire RSA keys from DNS but do not yet
+ have code to validate Secure DNS signatures.</P>
+<H4><A name="PKI">Key exchange using a PKI</A></H4>
+<P>The IPsec RFCs allow key exchange based on authentication services
+ provided by a<A href="#PKI"> PKI</A> or Public Key Infrastructure. With
+ many vendors selling such products and many large organisations
+ building these infrastructures, this will clearly be an important
+ application of IPsec and one Linux FreeS/WAN will eventually support.</P>
+<P>On the other hand, this is not as high a priority for Linux FreeS/WAN
+ as solutions based on<A href="#SDNS"> secure DNS</A>. We do not expect
+ any PKI to become as universal as DNS.</P>
+<P>Some<A href="#patch"> patches</A> to handle authentication with X.509
+ certificates, which most PKIs use, are available.</P>
+<H4><A name="photuris">Photuris</A></H4>
+<P><A href="#photuris">Photuris</A> is another key management protocol,
+ an alternative to IKE and ISAKMP, described in RFCs 2522 and 2523 which
+ are labelled &quot;experimental&quot;. Adding Photuris support to Linux FreeS/WAN
+ might be a good project for a volunteer. The likely starting point
+ would be the OpenBSD photurisd code.</P>
+<H4><A name="skip">SKIP</A></H4>
+<P><A href="#SKIP">SKIP</A> is yet another key management protocol,
+ developed by Sun. At one point it was fairly widely used, but it now
+ seems moribund, displaced by IKE. Sun now (as of Solaris 8.0) ship an
+ IPsec implementation using IKE. We have no plans to implement SKIP. If
+ a user were to implement it, we would almost certainly not want to add
+ the code to our distribution.</P>
+<HR>
+<H1><A name="lists">Mailing lists and newsgroups</A></H1>
+<H2><A name="list.fs">Mailing lists about FreeS/WAN</A></H2>
+<H3><A name="projlist">The project mailing lists</A></H3>
+<P>The Linux FreeS/WAN project has several email lists for user support,
+ bug reports and software development discussions.</P>
+<P>We had a single list on clinet.fi for several years (Thanks, folks!),
+ then one list on freeswan.org, but now we've split into several lists:</P>
+<DL>
+<DT><A href="mailto:users-request@lists.freeswan.org?body=subscribe">
+users</A></DT>
+<DD>
+<UL>
+<LI>The general list for discussing use of the software</LI>
+<LI>The place for seeking<STRONG> help with problems</STRONG> (but
+ please check the<A href="faq.html"> FAQ</A> first).</LI>
+<LI>Anyone can post.</LI>
+</UL>
+</DD>
+<DT><A href="mailto:bugs-request@lists.freeswan.org?body=subscribe">bugs</A>
+</DT>
+<DD>
+<UL>
+<LI>For<STRONG> bug reports</STRONG>.</LI>
+<LI>If you are not certain what is going on -- could be a bug, a
+ configuration error, a network problem, ... -- please post to the users
+ list instead.</LI>
+<LI>Anyone can post.</LI>
+</UL>
+</DD>
+<DT><A href="mailto:design-request@lists.freeswan.org?body=subscribe">
+design</A></DT>
+<DD>
+<UL>
+<LI><STRONG>Design discussions</STRONG>, for people working on FreeS/WAN
+ development or others with an interest in design and security issues.</LI>
+<LI>It would be a good idea to read the existing design papers (see this<A
+href="#applied"> list</A>) before posting.</LI>
+<LI>Anyone can post.</LI>
+</UL>
+</DD>
+<DT><A href="mailto:announce-request@lists.freeswan.org?body=subscribe">
+announce</A></DT>
+<DD>
+<UL>
+<LI>A<STRONG> low-traffic</STRONG> list.</LI>
+<LI><STRONG>Announcements</STRONG> about FreeS/WAN and related software.</LI>
+<LI>All posts here are also sent to the users list. You need not
+ subscribe to both.</LI>
+<LI>Only the FreeS/WAN team can post.</LI>
+<LI>If you have something you feel should go on this list, send it to<VAR>
+ announce-admin@lists.freeswan.org</VAR>. Unless it is obvious, please
+ include a short note explaining why we should post it.</LI>
+</UL>
+</DD>
+<DT><A href="mailto:briefs-request@lists.freeswan.org?body=subscribe">
+briefs</A></DT>
+<DD>
+<UL>
+<LI>A<STRONG> low-traffic</STRONG> list.</LI>
+<LI><STRONG>Weekly summaries</STRONG> of activity on the users list.</LI>
+<LI>All posts here are also sent to the users list. You need not
+ subscribe to both.</LI>
+<LI>Only the FreeS/WAN team can post.</LI>
+</UL>
+</DD>
+</DL>
+<P>To subscribe to any of these, you can:</P>
+<UL>
+<LI>just follow the links above</LI>
+<LI>use our<A href="http://www.freeswan.org/mail.html"> web interface</A>
+</LI>
+<LI>send mail to<VAR> listname</VAR>-request@lists.freeswan.org with a
+ one-line message body &quot;subscribe&quot;</LI>
+</UL>
+<P>Archives of these lists are available via the<A href="http://www.freeswan.org/mail.html">
+ web interface</A>.</P>
+<H4><A name="which.list">Which list should I use?</A></H4>
+<P>For most questions, please check the<A href="faq.html"> FAQ</A>
+ first, and if that does not have an answer, ask on the users list. &quot;My
+ configuration doesn't work.&quot; does not belong on the bugs list, and &quot;Can
+ FreeS/WAN do such-and-such&quot; or &quot;How do I configure it to...&quot; do not
+ belong in design discussions.</P>
+<P>Cross-posting the same message to two or more of these lists is
+ discouraged. Quite a few people read more than one list and getting
+ multiple copies is annoying.</P>
+<H4><A name="policy.list">List policies</A></H4>
+<P><STRONG>US citizens or residents are asked not to post code to the
+ lists, not even one-line bug fixes</STRONG>. The project cannot accept
+ code which might entangle it in US<A href="#exlaw"> export restrictions</A>
+.</P>
+<P>Non-subscribers can post to some of these lists. This is necessary;
+ someone working on a gateway install who encounters a problem may not
+ have access to a subscribed account.</P>
+<P>Some spam turns up on these lists from time to time. For discussion
+ of why we do not attempt to filter it, see the<A href="#spam"> FAQ</A>.
+ Please do not clutter the lists with complaints about this.</P>
+<H3><A name="archive">Archives of the lists</A></H3>
+<P>Searchable archives of the old single list have existed for some
+ time. At time of writing, it is not yet clear how they will change for
+ the new multi-list structure.</P>
+<UL>
+<LI><A href="http://www.sandelman.ottawa.on.ca/linux-ipsec">Canada</A></LI>
+<LI><A href="http://www.nexial.com">Holland</A></LI>
+</UL>
+<P>Note that these use different search engines. Try both.</P>
+<P>Archives of the new lists are available via the<A href="http://www.freeswan.org/mail.html">
+ web interface</A>.</P>
+<H2><A name="indexes">Indexes of mailing lists</A></H2>
+<P><A href="http://paml.net/">PAML</A> is the standard reference for<STRONG>
+ P</STRONG>ublicly<STRONG> A</STRONG>ccessible<STRONG> M</STRONG>ailing<STRONG>
+ L</STRONG>ists. When we last checked, it had over 7500 lists on an
+ amazing variety of topics. It also has FAQ information and a search
+ engine.</P>
+<P>There is an index of<A href="http://oslab.snu.ac.kr/~djshin/linux/mail-list/index.shtml">
+ Linux mailing lists</A> available.</P>
+<P>A list of<A href="http://xforce.iss.net/maillists/otherlists.php">
+ computer security mailing lists</A>, with descriptions.</P>
+<H2><A name="otherlists">Lists for related software and topics</A></H2>
+<P>Most links in this section point to subscription addresses for the
+ various lists. Send the one-line message &quot;subscribe<VAR> list_name</VAR>
+&quot; to subscribe to any of them.</P>
+<H3><A NAME="28_3_1">Products that include FreeS/WAN</A></H3>
+<P>Our introduction document gives a<A href="#products"> list of
+ products that include FreeS/WAN</A>. If you have, or are considering,
+ one of those, check the supplier's web site for information on mailing
+ lists for their users.</P>
+<H3><A name="linux.lists">Linux mailing lists</A></H3>
+<UL>
+<LI><A href="mailto:majordomo@vger.kernel.org">
+linux-admin@vger.kernel.org</A>, for Linux system administrators</LI>
+<LI><A href="mailto:netfilter-request@lists.samba.org">
+netfilter@lists.samba.org</A>, about Netfilter, which replaces IPchains
+ in kernels 2.3.15 and later</LI>
+<LI><A href="mailto:security-audit-request@ferret.lmh.ox.ac.uk">
+security-audit@ferret.lmh.ox.ac.uk</A>, for people working on security
+ audits of various Linux programs</LI>
+<LI><A href="mailto:securedistros-request@humbolt.geo.uu.nl">
+securedistros@humbolt.geo.uu.nl</A>, for discussion of issues common to
+ all the half dozen projects working on secure Linux distributions.</LI>
+</UL>
+<P>Each of the scure distribution projects also has its own web site and
+ mailing list. Some of the sites are:</P>
+<UL>
+<LI><A href="http://bastille-linux.org/">Bastille Linux</A> scripts to
+ harden Redhat, e.g. by changing permissions and modifying inialisation
+ scripts</LI>
+<LI><A href="http://immunix.org/">Immunix</A> take a different approach,
+ using a modified compiler to build kernel and utilities with better
+ resistance to various types of overflow and exploit</LI>
+<LI>the<A href="#NSA"> NSA</A> have contractors working on a<A href="#SElinux">
+ Security Enhanced Linux</A>, primarily adding stronger access control
+ mechanisms. You can download the current version (which interestingly
+ is under GPL and not export resrtricted) or subscribe to the mailing
+ list from the<A href="http://www.nsa.gov/selinux"> project web page</A>
+.</LI>
+</UL>
+<H3><A name="ietf">Lists for IETF working groups</A></H3>
+<P>Each<A href="#ietf"> IETF</A> working group has an associated mailing
+ list where much of the work takes place.</P>
+<UL>
+<LI><A href="mailto:majordomo@lists.tislabs.com">ipsec@lists.tislabs.com</A>
+, the IPsec<A href="http://www.ietf.org/html.charters/ipsec-charter.html">
+ working group</A>. This is where the protocols are discussed, new
+ drafts announced, and so on. By now, the IPsec working group is winding
+ down since the work is essentially complete. A<A href="http://www.sandelman.ottawa.on.ca/ipsec/">
+ list archive</A> is available.</LI>
+<LI><A href="mailto:ipsec-policy-request@vpnc.org">IPsec policy</A>
+ list, and its<A href="http://www.vpnc.org/ipsec-policy/"> archive</A></LI>
+<LI><A href="mailto:ietf-ipsra-request@vpnc.org">IP secure remote access</A>
+ list, and its<A href="http://www.vpnc.org/ietf-ipsra/mail-archive/">
+ archive</A></LI>
+</UL>
+<H3><A name="other">Other mailing lists</A></H3>
+<UL>
+<LI><A href="mailto:ipc-announce-request@privacy.org">
+ipc-announce@privacy.org</A> a low-traffic list with announcements of
+ developments in privacy, encryption and online civil rights</LI>
+<LI>a VPN mailing list's<A href="http://kubarb.phsx.ukans.edu/~tbird/vpn.html">
+ home page</A></LI>
+</UL>
+<H2><A name="newsgroups">Usenet newsgroups</A></H2>
+<UL>
+<LI>sci.crypt</LI>
+<LI>sci.crypt.research</LI>
+<LI>comp.dcom.vpn</LI>
+<LI>talk.politics.crypto</LI>
+</UL>
+<HR>
+<H1><A name="weblink">Web links</A></H1>
+<H2><A name="freeswan">The Linux FreeS/WAN Project</A></H2>
+<P>The main project web site is<A href="http://www.freeswan.org/">
+ www.freeswan.org</A>.</P>
+<P>Links to other project-related<A href="#sites"> sites</A> are
+ provided in our introduction section.</P>
+<H3><A name="patch">Add-ons and patches for FreeS/WAN</A></H3>
+<P>Some user-contributed patches have been integrated into the FreeS/WAN
+ distribution. For a variety of reasons, those listed below have not.</P>
+<P>Note that not all patches are a good idea.</P>
+<UL>
+<LI>There are a number of &quot;features&quot; of IPsec which we do not implement
+ because they reduce security. See this<A href="#dropped"> discussion</A>
+. We do not recommend using patches that implement these. One example is
+ aggressive mode.</LI>
+<LI>We do not recommend adding &quot;features&quot; of any sort unless they are
+ clearly necessary, or at least have clear benefits. For example,
+ FreeS/WAN would not become more secure if it offerred a choice of 14
+ ciphers. If even one was flawed, it would certainly become less secure
+ for anyone using that cipher. Even with 14 wonderful ciphers, it would
+ be harder to maintain and administer, hence more vulnerable to various
+ human errors.</LI>
+</UL>
+<P>This is not to say that patches are necessarily bad, only that using
+ them requires some deliberation. For example, there might be perfectly
+ good reasons to add a specific cipher in your application: perhaps GOST
+ to comply with government standards in Eastern Europe, or AES for
+ performance benefits.</P>
+<H4><A NAME="29_1_1_1">Current patches</A></H4>
+<P>Patches believed current::</P>
+<UL>
+<LI>patches for<A href="http://www.strongsec.com/freeswan/"> X.509
+ certificate support</A>, also available from a<A href="http://www.twi.ch/~sna/strongsec/freeswan/">
+ mirror site</A></LI>
+<LI>patches to add<A href="http://www.irrigacion.gov.ar/juanjo/ipsec">
+ AES and other ciphers</A>. There is preliminary data indicating AES
+ gives a substantial<A href="#perf.more"> performance gain</A>.</LI>
+</UL>
+<P>There is also one add-on that takes the form of a modified FreeS/WAN
+ distribution, rather than just patches to the standard distribution:</P>
+<UL>
+<LI><A href="http://www.ipv6.iabg.de/downloadframe/index.html">IPv6
+ support</A></LI>
+</UL>
+<P>Before using any of the above,, check the<A href="mail.html"> mailing
+ lists</A> for news of newer versions and to see whether they have been
+ incorporated into more recent versions of FreeS/WAN.</P>
+<H4><A NAME="29_1_1_2">Older patches</A></H4>
+<UL>
+<LI><A href="http://sources.colubris.com/en/projects/FreeSWAN/">hardware
+ acceleration</A></LI>
+<LI>a<A href="http://tzukanov.narod.ru/"> series</A> of patches that
+<UL>
+<LI>provide GOST, a Russian gov't. standard cipher, in MMX assembler</LI>
+<LI>add GOST to OpenSSL</LI>
+<LI>add GOST to the International kernel patch</LI>
+<LI>let FreeS/WAN use International kernel patch ciphers</LI>
+</UL>
+</LI>
+<LI>Neil Dunbar's patches for<A href="ftp://hplose.hpl.hp.com/pub/nd/pluto-openssl.tar.gz">
+ certificate support</A>, using code from<A href="http://www.openssl.org">
+ Open SSL</A>.</LI>
+<LI>Luc Lanthier's<A href="ftp://ftp.netwinder.org/users/f/firesoul/">
+ patches</A> for<A href="#PKIX"> PKIX</A> support.</LI>
+<LI><A href="ftp://ftp.heise.de/pub/ct/listings/9916-180.tgz">patches</A>
+ to add<A href="#Blowfish"> Blowfish</A>,<A href="#IDEA"> IDEA</A> and<A href="#CAST128">
+ CAST-128</A> to FreeS/WAN</LI>
+<LI>patches for FreeS/WAN 1.3, Pluto support for<A href="http://alcatraz.webcriminals.com/~bastiaan/ipsec/">
+ external authentication</A>, for example with a smartcard or SKEYID.</LI>
+<LI><A href="http://www.zengl.net/freeswan/download/">patches and
+ utilities</A> for using FreeS/WAN with PGPnet</LI>
+<LI><A href="http://www.freelith.com/lithworks/crypto/freeswan_patch.htm">
+Blowfish encryption and Tiger hash</A></LI>
+<LI><A href="http://www.cendio.se/~bellman/aggressive-pluto.snap.tar.gz">
+patches</A> for aggressive mode support</LI>
+</UL>
+<P>These patches are for older versions of FreeS/WAN and will likely not
+ work with the current version. Older versions of FreeS/WAN may be
+ available on some of the<A href="#sites"> distribution sites</A>, but
+ we recommend using the current release.</P>
+<H4><A name="VPN.masq">VPN masquerade patches</A></H4>
+<P>Finally, there are some patches to other code that may be useful with
+ FreeS/WAN:</P>
+<UL>
+<LI>a<A href="ftp://ftp.rubyriver.com/pub/jhardin/masquerade/ip_masq_vpn.html">
+ patch</A> to make IPsec, PPTP and SSH VPNs work through a Linux
+ firewall with<A href="#masq"> IP masquerade</A>.</LI>
+<LI><A href="http://www.linuxdoc.org/HOWTO/VPN-Masquerade-HOWTO.html">
+Linux VPN Masquerade HOWTO</A></LI>
+</UL>
+<P>Note that this is not required if the same machine does IPsec and
+ masquerading, only if you want a to locate your IPsec gateway on a
+ masqueraded network. See our<A href="#NAT"> firewalls</A> document for
+ discussion of why this is problematic.</P>
+<P>At last report, this patch could not co-exist with FreeS/WAN on the
+ same machine.</P>
+<H3><A name="dist">Distributions including FreeS/WAN</A></H3>
+<P>The introductory section of our document set lists several<A href="#distwith">
+ Linux distributions</A> which include FreeS/WAN.</P>
+<H3><A name="used">Things FreeS/WAN uses or could use</A></H3>
+<UL>
+<LI><A href="http://openpgp.net/random">/dev/random</A> support page,
+ discussion of and code for the Linux<A href="#random"> random number
+ driver</A>. Out-of-date when we last checked (January 2000), but still
+ useful.</LI>
+<LI>other programs related to random numbers:
+<UL>
+<LI><A href="http://www.mindrot.org/audio-entropyd.html">audio entropy
+ daemon</A> to gather noise from a sound card and feed it into
+ /dev/random</LI>
+<LI>an<A href="http://www.lothar.com/tech/crypto/"> entropy-gathering
+ daemon</A></LI>
+<LI>a driver for the random number generator in recent<A href="http://sourceforge.net/projects/gkernel/">
+ Intel chipsets</A>. This driver is included as standard in 2.4 kernels.</LI>
+</UL>
+</LI>
+<LI>a Linux<A href="http://www.marko.net/l2tp/"> L2TP Daemon</A> which
+ might be useful for communicating with Windows 2000 which builds L2TP
+ tunnels over its IPsec connections</LI>
+<LI>to use opportunistic encryption, you need a recent version of<A href="#BIND">
+ BIND</A>. You can get one from the<A href="http://www.isc.org">
+ Internet Software Consortium</A> who maintain BIND.</LI>
+</UL>
+<H3><A name="alternatives">Other approaches to VPNs for Linux</A></H3>
+<UL>
+<LI>other Linux<A href="#linuxipsec"> IPsec implementations</A></LI>
+<LI><A href="http://www.tik.ee.ethz.ch/~skip/">ENskip</A>, a free
+ implementation of Sun's<A href="#SKIP"> SKIP</A> protocol</LI>
+<LI><A href="http://sunsite.auc.dk/vpnd/">vpnd</A>, a non-IPsec VPN
+ daemon for Linux which creates tunnels using<A href="#Blowfish">
+ Blowfish</A> encryption</LI>
+<LI><A href="http://www.winton.org.uk/zebedee/">Zebedee</A>, a simple
+ GPLd tunnel-building program with Linux and Win32 versions. The name is
+ from<STRONG> Z</STRONG>lib compression,<STRONG> B</STRONG>lowfish
+ encryption and<STRONG> D</STRONG>iffie-Hellman key exchange.</LI>
+<LI>There are at least two PPTP implementations for Linux
+<UL>
+<LI>Moreton Bay's<A href="http://www.moretonbay.com/vpn/pptp.html">
+ PoPToP</A></LI>
+<LI><A href="http://cag.lcs.mit.edu/~cananian/Projects/PPTP/">PPTP-Linux</A>
+</LI>
+</UL>
+</LI>
+<LI><A href="http://sites.inka.de/sites/bigred/devel/cipe.html">CIPE</A>
+ (crypto IP encapsulation) project, using their own lightweight protocol
+ to encrypt between routers</LI>
+<LI><A href="http://tinc.nl.linux.org/">tinc</A>, a VPN Daemon</LI>
+</UL>
+<P>There is a list of<A href="http://www.securityportal.com/lskb/10000000/kben10000005.html">
+ Linux VPN</A> software in the<A href="http://www.securityportal.com/lskb/kben00000001.html">
+ Linux Security Knowledge Base</A>.</P>
+<H2><A name="ipsec.link">The IPsec Protocols</A></H2>
+<H3><A name="general">General IPsec or VPN information</A></H3>
+<UL>
+<LI>The<A href="http://www.vpnc.org"> VPN Consortium</A> is a group for
+ vendors of IPsec products. Among other things, they have a good
+ collection of<A href="http://www.vpnc.org/white-papers.html"> IPsec
+ white papers</A>.</LI>
+<LI>A VPN mailing list with a<A href="http://kubarb.phsx.ukans.edu/~tbird/vpn.html">
+ home page</A>, a FAQ, some product comparisons, and many links.</LI>
+<LI><A href="http://www.opus1.com/vpn/index.html">VPN pointer page</A></LI>
+<LI>a<A href="http://www.epm.ornl.gov/~dunigan/vpn.html"> collection</A>
+ of VPN links, and some explanation</LI>
+</UL>
+<H3><A name="overview">IPsec overview documents or slide sets</A></H3>
+<UL>
+<LI>the FreeS/WAN<A href="ipsec.html"> document section</A> on these
+ protocols</LI>
+</UL>
+<H3><A name="otherlang">IPsec information in languages other than
+ English</A></H3>
+<UL>
+<LI><A href="http://www.imib.med.tu-dresden.de/imib/Internet/Literatur/ipsec-docu.html">
+German</A></LI>
+<LI><A href="http://www.kame.net/index-j.html">Japanese</A></LI>
+<LI>Feczak Szabolcs' thesis in<A href="http://feczo.koli.kando.hu/vpn/">
+ Hungarian</A></LI>
+<LI>Davide Cerri's thesis and some presentation slides<A href="http://www.linux.it/~davide/doc/">
+ Italian</A></LI>
+</UL>
+<H3><A name="RFCs1">RFCs and other reference documents</A></H3>
+<UL>
+<LI><A href="rfc.html">Our document</A> listing the RFCs relevant to
+ Linux FreeS/WAN and giving various ways of obtaining both RFCs and
+ Internet Drafts.</LI>
+<LI><A href="http://www.vpnc.org/vpn-standards.html">VPN Standards</A>
+ page maintained by<A href="#VPNC"> VPNC</A>. This covers both RFCs and
+ Drafts, and classifies them in a fairly helpful way.</LI>
+<LI><A href="http://www.rfc-editor.org">RFC archive</A></LI>
+<LI><A href="http://www.ietf.org/ids.by.wg/ipsec.html">Internet Drafts</A>
+ related to IPsec</LI>
+<LI>US government<A href="http://www.itl.nist.gov/div897/pubs"> site</A>
+ with their<A href="#FIPS"> FIPS</A> standards</LI>
+<LI>Archives of the ipsec@tis.com mailing list where discussion of
+ drafts takes place.
+<UL>
+<LI><A href="http://www.sandelman.ottawa.on.ca/ipsec">Eastern Canada</A></LI>
+<LI><A href="http://www.vpnc.org/ietf-ipsec">California</A>.</LI>
+</UL>
+</LI>
+</UL>
+<H3><A name="analysis">Analysis and critiques of IPsec protocols</A></H3>
+<UL>
+<LI>Counterpane's<A href="http://www.counterpane.com/ipsec.pdf">
+ evaluation</A> of the protocols</LI>
+<LI>Simpson's<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/1999/06/msg00319.html">
+ IKE Considered Dangerous</A> paper. Note that this is a link to an
+ archive of our mailing list. There are several replies in addition to
+ the paper itself.</LI>
+<LI>Fate Labs<A href="http://www.fatelabs.com/loki-vpn.pdf"> Virual
+ Private Problems: the Broken Dream</A></LI>
+<LI>Catherine Meadows' paper<CITE> Analysis of the Internet Key Exchange
+ Protocol Using the NRL Protocol Analyzer</CITE>, in<A href="http://chacs.nrl.navy.mil/publications/CHACS/1999/1999meadows-IEEE99.pdf">
+ PDF</A> or<A href="http://chacs.nrl.navy.mil/publications/CHACS/1999/1999meadows-IEEE99.ps">
+ Postscript</A>.</LI>
+<LI>Perlman and Kaufmnan
+<UL>
+<LI><A href="http://snoopy.seas.smu.edu/ee8392_summer01/week7/perlman2.pdf">
+Key Exchange in IPsec</A></LI>
+<LI>a newer<A href="http://sec.femto.org/wetice-2001/papers/radia-paper.pdf">
+ PDF paper</A>,<CITE> Analysis of the IPsec Key Exchange Standard</CITE>
+.</LI>
+</UL>
+</LI>
+<LI>Bellovin's<A href="http://www.research.att.com/~smb/papers/index.html">
+ papers</A> page including his:
+<UL>
+<LI><CITE>Security Problems in the TCP/IP Protocol Suite</CITE> (1989)</LI>
+<LI><CITE>Problem Areas for the IP Security Protocols</CITE> (1996)</LI>
+<LI><CITE>Probable Plaintext Cryptanalysis of the IP Security Protocols</CITE>
+ (1997)</LI>
+</UL>
+</LI>
+<LI>An<A href="http://www.lounge.org/ike_doi_errata.html"> errata list</A>
+ for the IPsec RFCs.</LI>
+</UL>
+<H3><A name="IP.background">Background information on IP</A></H3>
+<UL>
+<LI>An<A href="http://ipprimer.windsorcs.com/"> IP tutorial</A> that
+ seems to be written mainly for Netware or Microsoft LAN admins entering
+ a new world</LI>
+<LI><A href="http://www.iana.org">IANA</A>, Internet Assigned Numbers
+ Authority</LI>
+<LI><A href="http://public.pacbell.net/dedicated/cidr.html">CIDR</A>,
+ Classless Inter-Domain Routing</LI>
+<LI>Also see our<A href="biblio.html"> bibliography</A></LI>
+</UL>
+<H2><A name="implement">IPsec Implementations</A></H2>
+<H3><A name="linuxprod">Linux products</A></H3>
+<P>Vendors using FreeS/WAN in turnkey firewall or VPN products are
+ listed in our<A href="#turnkey"> introduction</A>.</P>
+<P>Other vendors have Linux IPsec products which, as far as we know, do
+ not use FreeS/WAN</P>
+<UL>
+<LI><A href="http://www.redcreek.com/products/shareware.html">Redcreek</A>
+ provide an open source Linux driver for their PCI hardware VPN card.
+ This card has a 100 Mbit Ethernet port, an Intel 960 CPU plus more
+ specialised crypto chips, and claimed encryption performance of 45
+ Mbit/sec. The PC sees it as an Ethernet board.</LI>
+<LI><A href="http://linuxtoday.com/stories/8428.html?nn">Paktronix</A>
+ offer a Linux-based VPN with hardware encryption</LI>
+<LI><A href="http://www.watchguard.com/">Watchguard</A> use Linux in
+ their Firebox product.</LI>
+<LI><A href="http://www.entrust.com">Entrust</A> offer a developers'
+ toolkit for using their<A href="#PKI"> PKI</A> for IPsec authentication</LI>
+<LI>According to a report on our mailing list,<A href="http://www.axent.com">
+ Axent</A> have a Linux version of their product.</LI>
+</UL>
+<H3><A name="router">IPsec in router products</A></H3>
+<P>All the major router vendors support IPsec, at least in some models.</P>
+<UL>
+<LI><A href="http://www.cisco.com/warp/public/707/16.html">Cisco</A>
+ IPsec information</LI>
+<LI>Ascend, now part of<A href="http://www.lucent.com/"> Lucent</A>,
+ have some IPsec-based products</LI>
+<LI><A href="http://www.nortelnetworks.com/">Bay Networks</A>, now part
+ of Nortel, use IPsec in their Contivity switch product line</LI>
+<LI><A href="http://www.3com.com/products/enterprise.html">3Com</A> have
+ a number of VPN products, some using IPsec</LI>
+</UL>
+<H3><A name="fw.web">IPsec in firewall products</A></H3>
+<P>Many firewall vendors offer IPsec, either as a standard part of their
+ product, or an optional extra. A few we know about are:</P>
+<UL>
+<LI><A href="http://www.borderware.com/">Borderware</A></LI>
+<LI><A href="http://www.ashleylaurent.com/vpn/ipsec_vpn.htm">Ashley
+ Laurent</A></LI>
+<LI><A href="http://www.watchguard.com">Watchguard</A></LI>
+<LI><A href="http://www.fx.dk/firewall/ipsec.html">Injoy</A> for OS/2</LI>
+</UL>
+<P>Vendors using FreeS/WAN in turnkey firewall products are listed in
+ our<A href="#turnkey"> introduction</A>.</P>
+<H3><A name="ipsecos">Operating systems with IPsec support</A></H3>
+<P>All the major open source operating systems support IPsec. See below
+ for details on<A href="#BSD"> BSD-derived</A> Unix variants.</P>
+<P>Among commercial OS vendors, IPsec players include:</P>
+<UL>
+<LI><A href="http://msdn.microsoft.com/isapi/msdnlib.idc?theURL=/library/backgrnd/html/msdn_ip_security.htm">
+Microsoft</A> have put IPsec in their Windows 2000 and XP products</LI>
+<LI><A href="http://www.s390.ibm.com/stories/1999/os390v2r8_pr.html">IBM</A>
+ announce a release of OS390 with IPsec support via a crypto
+ co-processor</LI>
+<LI><A href="http://www.sun.com/solaris/ds/ds-security/ds-security.pdf">
+Sun</A> include IPsec in Solaris 8</LI>
+<LI><A href="http://www.hp.com/security/products/extranet-security.html">
+Hewlett Packard</A> offer IPsec for their Unix machines</LI>
+<LI>Certicom have IPsec available for the<A href="http://www.certicom.com/products/movian/movianvpn_tech.html">
+ Palm</A>.</LI>
+<LI>There were reports before the release that Apple's Mac OS X would
+ have IPsec support built in, but it did not seem to be there when we
+ last checked. If you find, it please let us know via the<A href="mail.html">
+ mailing list</A>.</LI>
+</UL>
+<H3><A NAME="29_3_5">IPsec on network cards</A></H3>
+<P>Network cards with built-in IPsec acceleration are available from at
+ least Intel, 3Com and Redcreek.</P>
+<H3><A name="opensource">Open source IPsec implementations</A></H3>
+<H4><A name="linuxipsec">Other Linux IPsec implementations</A></H4>
+<P>We like to think of FreeS/WAN as<EM> the</EM> Linux IPsec
+ implementation, but it is not the only one. Others we know of are:</P>
+<UL>
+<LI><A href="http://www.enst.fr/~beyssac/pipsec/">pipsecd</A>, a
+ lightweight implementation of IPsec for Linux. Does not require kernel
+ recompilation.</LI>
+<LI>Petr Novak's<A href="ftp://ftp.eunet.cz/icz/ipnsec/"> ipnsec</A>,
+ based on the OpenBSD IPsec code and using<A href="#photuris"> Photuris</A>
+ for key management</LI>
+<LI>A now defunct project at<A href="http://www.cs.arizona.edu/security/hpcc-blue/linux.html">
+ U of Arizona</A> (export controlled)</LI>
+<LI><A href="http://snad.ncsl.nist.gov/cerberus">NIST Cerebus</A>
+ (export controlled)</LI>
+</UL>
+<H4><A name="BSD">IPsec for BSD Unix</A></H4>
+<UL>
+<LI><A href="http://www.kame.net/project-overview.html">KAME</A>,
+ several large Japanese companies co-operating on IPv6 and IPsec</LI>
+<LI><A href="http://web.mit.edu/network/isakmp">US Naval Research Lab</A>
+ implementation of IPv6 and of IPsec for IPv4 (export controlled)</LI>
+<LI><A href="http://www.openbsd.org">OpenBSD</A> includes IPsec as a
+ standard part of the distribution</LI>
+<LI><A href="http://www.r4k.net/ipsec">IPsec for FreeBSD</A></LI>
+<LI>a<A href="http://www.netbsd.org/Documentation/network/ipsec/"> FAQ</A>
+ on NetBSD's IPsec implementation</LI>
+</UL>
+<H4><A name="misc">IPsec for other systems</A></H4>
+<UL>
+<LI><A href="http://www.tcm.hut.fi/Tutkimus/IPSEC/">Helsinki U of
+ Technolgy</A> have implemented IPsec for Solaris, Java and Macintosh</LI>
+</UL>
+<H3><A name="interop.web">Interoperability</A></H3>
+<P>The IPsec protocols are designed so that different implementations
+ should be able to work together. As they say &quot;the devil is in the
+ details&quot;. IPsec has a lot of details, but considerable success has been
+ achieved.</P>
+<H4><A name="result">Interoperability results</A></H4>
+<P>Linux FreeS/WAN has been tested for interoperability with many other
+ IPsec implementations. Results to date are in our<A href="interop.html">
+ interoperability</A> section.</P>
+<P>Various other sites have information on interoperability between
+ various IPsec implementations:</P>
+<UL>
+<LI><A href="http://www.opus1.com/vpn/atl99display.html">interop results</A>
+ from a bakeoff in Atlanta, September 1999.</LI>
+<LI>a French company, HSC's,<A href="http://www.hsc.fr/ressources/presentations/ipsec99/index.html.en">
+ interoperability</A> test data covers FreeS/WAN, Open BSD, KAME, Linux
+ pipsecd, Checkpoint, Red Creek Ravlin, and Cisco IOS</LI>
+<LI><A href="http://www.icsa.net/">ICSA</A> offer certification programs
+ for various security-related products. See their list of<A href="http://www.icsa.net/html/communities/ipsec/certification/certified_products/index.shtml">
+ certified IPsec</A> products. Linux FreeS/WAN is not currently on that
+ list, but several products with which we interoperate are.</LI>
+<LI>VPNC have a page on why they are not yet doing<A href="http://www.vpnc.org/interop.html">
+ interoperability</A> testing and a page on the<A href="http://www.vpnc.org/conformance.html">
+ spec conformance</A> testing that they are doing</LI>
+<LI>a<A href="http://www.commweb.com/article/COM20000912S0009"> review</A>
+ comparing a dozen commercial IPsec implemetations. Unfortunately, the
+ reviewers did not look at Open Source implementations such as FreeS/WAN
+ or OpenBSD.</LI>
+<LI><A href="http://www.tanu.org/~sakane/doc/public/report-ike-interop0007.html">
+results</A> from interoperability tests at a conference. FreeS/WAN was
+ not tested there.</LI>
+<LI>test results from the<A href="http://www.hsc.fr/ressources/veille/ipsec/ipsec2000/">
+ IPSEC 2000</A> conference</LI>
+</UL>
+<H4><A name="test1">Interoperability test sites</A></H4>
+<UL>
+<LI><A href="http://www.tahi.org/">TAHI</A>, a Japanese IPv6 testing
+ project with free IPsec validation software</LI>
+<LI><A href="http://ipsec-wit.antd.nist.gov">National Institute of
+ Standards and Technology</A></LI>
+<LI><A href="http://isakmp-test.ssh.fi/">SSH Communications Security</A></LI>
+</UL>
+<H2><A name="linux.link">Linux links</A></H2>
+<H3><A name="linux.basic">Basic and tutorial Linux information</A></H3>
+<UL>
+<LI>Linux<A href="http://linuxcentral.com/linux/LDP/LDP/gs/gs.html">
+ Getting Started</A> HOWTO document</LI>
+<LI>A getting started guide from the<A href="http://darkwing.uoregon.edu/~cchome/linuxgettingstarted.html">
+ U of Oregon</A></LI>
+<LI>A large<A href="http://www.herring.org/techie.html"> link collection</A>
+ which includes a lot of introductory and tutorial material on Unix,
+ Linux, the net, . . .</LI>
+</UL>
+<H3><A name="general">General Linux sites</A></H3>
+<UL>
+<LI><A href="http://www.freshmeat.net">Freshmeat</A> Linux news</LI>
+<LI><A href="http://slashdot.org">Slashdot</A> &quot;News for Nerds&quot;</LI>
+<LI><A href="http://www.linux.org">Linux Online</A></LI>
+<LI><A href="http://www.linuxhq.com">Linux HQ</A></LI>
+<LI><A href="http://www.tux.org">tux.org</A></LI>
+</UL>
+<H3><A name="docs.ldp">Documentation</A></H3>
+<P>Nearly any Linux documentation you are likely to want can be found at
+ the<A href="http://metalab.unc.edu/LDP"> Linux Documentation Project</A>
+ or LDP.</P>
+<UL>
+<LI><A href="http://metalab.unc.edu/LDP/HOWTO/META-FAQ.html">Meta-FAQ</A>
+ guide to Linux information sources</LI>
+<LI>The LDP's HowTo documents are a standard Linux reference. See this<A href="http://www.linuxdoc.org/docs.html#howto">
+ list</A>. Documents there most relevant to a FreeS/WAN gateway are:
+<UL>
+<LI><A href="http://metalab.unc.edu/LDP/HOWTO/Kernel-HOWTO.html">Kernel
+ HOWTO</A></LI>
+<LI><A href="http://metalab.unc.edu/LDP/HOWTO/Networking-Overview-HOWTO.html">
+Networking Overview HOWTO</A></LI>
+<LI><A href="http://metalab.unc.edu/LDP/HOWTO/Security-HOWTO.html">
+Security HOWTO</A></LI>
+</UL>
+</LI>
+<LI>The LDP do a series of Guides, book-sized publications with more
+ detail (and often more &quot;why do it this way?&quot;) than the HowTos. See this<A
+href="http://www.linuxdoc.org/guides.html"> list</A>. Documents there
+ most relevant to a FreeS/WAN gateway are:
+<UL>
+<LI><A href="http://www.tml.hut.fi/~viu/linux/sag/">System
+ Administrator's Guide</A></LI>
+<LI><A href="http://www.linuxdoc.org/LDP/nag2/index.html">Network
+ Adminstrator's Guide</A></LI>
+<LI><A href="http://www.seifried.org/lasg/">Linux Administrator's
+ Security Guide</A></LI>
+</UL>
+</LI>
+</UL>
+<P>You may not need to go to the LDP to get this material. Most Linux
+ distributions include the HowTos on their CDs and several include the
+ Guides as well. Also, most of the Guides and some collections of HowTos
+ are available in book form from various publishers.</P>
+<P>Much of the LDP material is also available in languages other than
+ English. See this<A href="http://www.linuxdoc.org/links/nenglish.html">
+ LDP page</A>.</P>
+<H3><A name="advroute.web">Advanced routing</A></H3>
+<P>The Linux IP stack has some new features in 2.4 kernels. Some HowTos
+ have been written:</P>
+<UL>
+<LI>several HowTos for the<A href="http://netfilter.samba.org/unreliable-guides/">
+ netfilter</A> firewall code in newer kernels</LI>
+<LI><A href="http://www.ds9a.nl/2.4Networking/HOWTO//cvs/2.4routing/output/2.4networking.html">
+2.4 networking</A> HowTo</LI>
+<LI><A href="http://www.ds9a.nl/2.4Networking/HOWTO//cvs/2.4routing/output/2.4routing.html">
+2.4 routing</A> HowTo</LI>
+</UL>
+<H3><A name="linsec">Security for Linux</A></H3>
+<P>See also the<A href="#docs.ldp"> LDP material</A> above.</P>
+<UL>
+<LI><A href="http://www.ecst.csuchico.edu/~dranch/LINUX/index-linux.html#trinityos">
+Trinity OS guide to setting up Linux</A></LI>
+<LI><A href="http://www.deter.com/unix">Unix security</A> page</LI>
+<LI><A href="http://linux01.gwdg.de/~alatham/">PPDD</A> encrypting
+ filesystem</LI>
+<LI><A href="http://EncryptionHOWTO.sourceforge.net/">Linux Encryption
+ HowTo</A> (outdated when last checked, had an Oct 2000 revision date in
+ March 2002)</LI>
+</UL>
+<H3><A name="firewall.linux">Linux firewalls</A></H3>
+<P>Our<A href="firewall.html"> FreeS/WAN and firewalls</A> document
+ includes links to several sets of<A href="#examplefw"> scripts</A>
+ known to work with FreeS/WAN.</P>
+<P>Other information sources:</P>
+<UL>
+<LI><A href="http://ipmasq.cjb.net/">IP Masquerade resource page</A></LI>
+<LI><A href="http://netfilter.samba.org/unreliable-guides/">netfilter</A>
+ firewall code in 2.4 kernels</LI>
+<LI>Our list of general<A href="#firewall.web"> firewall references</A>
+ on the web</LI>
+<LI><A href="http://users.dhp.com/~whisper/mason/">Mason</A>, a tool for
+ automatically configuring Linux firewalls</LI>
+<LI>the web cache software<A href="http://www.squid-cache.org/"> squid</A>
+ and<A href="http://www.squidguard.org/"> squidguard</A> which turns
+ Squid into a filtering web proxy</LI>
+</UL>
+<H3><A name="linux.misc">Miscellaneous Linux information</A></H3>
+<UL>
+<LI><A href="http://lwn.net/current/dists.php3">Linux distribution
+ vendors</A></LI>
+<LI><A href="http://www.linux.org/groups/">Linux User Groups</A></LI>
+</UL>
+<H2><A name="crypto.link">Crypto and security links</A></H2>
+<H3><A name="security">Crypto and security resources</A></H3>
+<H4><A name="std.links">The standard link collections</A></H4>
+<P>Two enormous collections of links, each the standard reference in its
+ area:</P>
+<DL>
+<DT>Gene Spafford's<A href="http://www.cerias.purdue.edu/coast/hotlist/">
+ COAST hotlist</A></DT>
+<DD>Computer and network security.</DD>
+<DT>Peter Gutmann's<A href="http://www.cs.auckland.ac.nz/~pgut001/links.html">
+ Encryption and Security-related Resources</A></DT>
+<DD>Cryptography.</DD>
+</DL>
+<H4><A name="FAQ">Frequently Asked Question (FAQ) documents</A></H4>
+<UL>
+<LI><A href="http://www.faqs.org/faqs/cryptography-faq/">Cryptography
+ FAQ</A></LI>
+<LI><A href="http://www.interhack.net/pubs/fwfaq">Firewall FAQ</A></LI>
+<LI><A href="http://www.whitefang.com/sup/secure-faq.html">Secure Unix
+ Programming FAQ</A></LI>
+<LI>FAQs for specific programs are listed in the<A href="#tools"> tools</A>
+ section below.</LI>
+</UL>
+<H4><A name="cryptover">Tutorials</A></H4>
+<UL>
+<LI>Gary Kessler's<A href="http://www.garykessler.net/library/crypto.html">
+ Overview of Cryptography</A></LI>
+<LI>Terry Ritter's<A href="http://www.ciphersbyritter.com/LEARNING.HTM">
+ introduction</A></LI>
+<LI>Peter Gutman's<A href="http://www.cs.auckland.ac.nz/~pgut001/tutorial/index.html">
+ cryptography</A> tutorial (500 slides in PDF format)</LI>
+<LI>Amir Herzberg of IBM's sildes for his course<A href="http://www.hrl.il.ibm.com/mpay/course.html">
+ Introduction to Cryptography and Electronic Commerce</A></LI>
+<LI>the<A href="http://www.gnupg.org/gph/en/manual/c173.html"> concepts
+ section</A> of the<A href="#GPG"> GNU Privacy Guard</A> documentation</LI>
+<LI>Bruce Schneier's self-study<A href="http://www.counterpane.com/self-study.html">
+ cryptanalysis</A> course</LI>
+</UL>
+<P>See also the<A href="#interesting"> interesting papers</A> section
+ below.</P>
+<H4><A name="standards">Crypto and security standards</A></H4>
+<UL>
+<LI><A href="http://csrc.nist.gov/cc">Common Criteria</A>, new
+ international computer and network security standards to replace the
+ &quot;Rainbow&quot; series</LI>
+<LI>AES<A href="http://csrc.nist.gov/encryption/aes/aes_home.htm">
+ Advanced Encryption Standard</A> which will replace DES</LI>
+<LI><A href="http://grouper.ieee.org/groups/1363">IEEE P-1363 public key
+ standard</A></LI>
+<LI>our collection of links for the<A href="#ipsec.link"> IPsec</A>
+ standards</LI>
+<LI>history of<A href="http://www.visi.com/crypto/evalhist/index.html">
+ formal evaluation</A> of security policies and implementation</LI>
+</UL>
+<H4><A name="quotes">Crypto quotes</A></H4>
+<P>There are several collections of cryptographic quotes on the net:</P>
+<UL>
+<LI><A href="http://www.eff.org/pub/EFF/quotes.eff">the EFF</A></LI>
+<LI><A href="http://www.samsimpson.com/cquotes.php">Sam Simpson</A></LI>
+<LI><A href="http://www.amk.ca/quotations/cryptography/page-1.html">AM
+ Kutchling</A></LI>
+</UL>
+<H3><A name="policy">Cryptography law and policy</A></H3>
+<H4><A name="legal">Surveys of crypto law</A></H4>
+<UL>
+<LI>International survey of<A href="http://cwis.kub.nl/~FRW/PEOPLE/koops/lawsurvy.htm">
+ crypto law</A>.</LI>
+<LI>International survey of<A href="http://rechten.kub.nl/simone/ds-lawsu.htm">
+ digital signature law</A></LI>
+</UL>
+<H4><A name="oppose">Organisations opposing crypto restrictions</A></H4>
+<UL>
+<LI>The<A href="#EFF"> EFF</A>'s archives on<A href="http://www.eff.org/pub/Privacy/">
+ privacy</A> and<A href="http://www.eff.org/pub/Privacy/ITAR_export/">
+ export control</A>.</LI>
+<LI><A href="http://www.gilc.org">Global Internet Liberty Campaign</A></LI>
+<LI><A href="http://www.cdt.org/crypto">Center for Democracy and
+ Technology</A></LI>
+<LI><A href="http://www.privacyinternational.org/">Privacy International</A>
+, who give out<A href="http://www.bigbrotherawards.org/"> Big Brother
+ Awards</A> to snoopy organisations</LI>
+</UL>
+<H4><A name="other.policy">Other information on crypto policy</A></H4>
+<UL>
+<LI><A href="ftp://ftp.isi.edu/in-notes/rfc1984.txt">RFC 1984</A>, the<A href="#IAB">
+ IAB</A> and<A href="#IESG"> IESG</A> Statement on Cryptographic
+ Technology and the Internet.</LI>
+<LI>John Young's collection of<A href="http://cryptome.org/"> documents</A>
+ of interest to the cryptography, open government and privacy movements,
+ organized chronologically</LI>
+<LI>AT&amp;T researcher Matt Blaze's Encryption, Privacy and Security<A href="http://www.crypto.com">
+ Resource Page</A></LI>
+<LI>A good<A href="http://cryptome.org/crypto97-ne.htm"> overview</A> of
+ the issues from Australia.</LI>
+</UL>
+<P>See also our documentation section on the<A href="politics.html">
+ history and politics</A> of cryptography.</P>
+<H3><A name="crypto.tech">Cryptography technical information</A></H3>
+<H4><A name="cryptolinks">Collections of crypto links</A></H4>
+<UL>
+<LI><A href="http://www.counterpane.com/hotlist.html">Counterpane</A></LI>
+<LI><A href="http://www.cs.auckland.ac.nz/~pgut001/links.html">Peter
+ Gutman's links</A></LI>
+<LI><A href="http://www.pca.dfn.de/eng/team/ske/pem-dok.html">PKI links</A>
+</LI>
+<LI><A href="http://crypto.yashy.com/www/">Robert Guerra's links</A></LI>
+</UL>
+<H4><A name="papers">Lists of online cryptography papers</A></H4>
+<UL>
+<LI><A href="http://www.counterpane.com/biblio">Counterpane</A></LI>
+<LI><A href="http://www.cryptography.com/resources/papers">
+cryptography.com</A></LI>
+<LI><A href="http://www.cryptosoft.com/html/secpub.htm">Cryptosoft</A></LI>
+</UL>
+<H4><A name="interesting">Particularly interesting papers</A></H4>
+<P>These papers emphasize important issues around the use of
+ cryptography, and the design and management of secure systems.</P>
+<UL>
+<LI><A href="http://www.counterpane.com/keylength.html">Key length
+ requirements for security</A></LI>
+<LI><A href="http://www.cl.cam.ac.uk/users/rja14/wcf.html">Why
+ Cryptosystems Fail</A></LI>
+<LI><A href="http://www.cdt.org/crypto/risks98/">Risks of escrowed
+ encryption</A></LI>
+<LI><A href="http://www.counterpane.com/pitfalls.html">Security pitfalls
+ in cryptography</A></LI>
+<LI><A href="http://www.acm.org/classics/sep95">Reflections on Trusting
+ Trust</A>, Ken Thompson on Trojan horse design</LI>
+<LI><A href="http://www.apache-ssl.org/disclosure.pdf">Security against
+ Compelled Disclosure</A>, how to maintain privacy in the face of legal
+ or other coersion</LI>
+</UL>
+<H3><A name="compsec">Computer and network security</A></H3>
+<H4><A name="seclink">Security links</A></H4>
+<UL>
+<LI><A href="http://www.cs.purdue.edu/coast/hotlist">COAST Hotlist</A></LI>
+<LI>DMOZ open directory project<A href="http://dmoz.org/Computers/Security/">
+ computer security</A> links</LI>
+<LI><A href="http://www-cse.ucsd.edu/users/bsy/sec.html">Bennet Yee</A></LI>
+<LI>Mike Fuhr's<A href="http://www.fuhr.org/~mfuhr/computers/security.html">
+ link collection</A></LI>
+<LI><A href="http://www.networkintrusion.co.uk/">links</A> with an
+ emphasis on intrusion detection</LI>
+</UL>
+<H4><A name="firewall.web">Firewall links</A></H4>
+<UL>
+<LI><A href="http://www.cs.purdue.edu/coast/firewalls">COAST firewalls</A>
+</LI>
+<LI><A href="http://www.zeuros.co.uk">Firewalls Resource page</A></LI>
+</UL>
+<H4><A name="vpn">VPN links</A></H4>
+<UL>
+<LI><A href="http://www.vpnc.org">VPN Consortium</A></LI>
+<LI>First VPN's<A href="http://www.firstvpn.com/research/rhome.html">
+ white paper</A> collection</LI>
+</UL>
+<H4><A name="tools">Security tools</A></H4>
+<UL>
+<LI>PGP -- mail encryption
+<UL>
+<LI><A href="http://www.pgp.com/">PGP Inc.</A> (part of NAI) for
+ commercial versions</LI>
+<LI><A href="http://web.mit.edu/network/pgp.html">MIT</A> distributes
+ the NAI product for non-commercial use</LI>
+<LI><A href="http://www.pgpi.org/">international</A> distribution site</LI>
+<LI><A href="http://gnupg.org">GNU Privacy Guard (GPG)</A></LI>
+<LI><A href="http://www.dk.pgp.net/pgpnet/pgp-faq/">PGP FAQ</A></LI>
+</UL>
+ A message in our mailing list archive has considerable detail on<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/12/msg00029.html">
+ available versions</A> of PGP and on IPsec support in them.
+<P><STRONG>Note:</STRONG> A fairly nasty bug exists in all commercial
+ PGP versions from 5.5 through 6.5.3. If you have one of those,<STRONG>
+ upgrade now</STRONG>.</P>
+</LI>
+<LI>SSH -- secure remote login
+<UL>
+<LI><A href="http://www.ssh.fi">SSH Communications Security</A>, for the
+ original software. It is free for trial, academic and non-commercial
+ use.</LI>
+<LI><A href="http://www.openssh.com/">Open SSH</A>, the Open BSD team's
+ free replacement</LI>
+<LI><A href="http://www.freessh.org/">freessh.org</A>, links to free
+ implementations for many systems</LI>
+<LI><A href="http://www.uni-karlsruhe.de/~ig25/ssh-faq">SSH FAQ</A></LI>
+<LI><A href="http://www.chiark.greenend.org.uk/~sgtatham/putty/">Putty</A>
+, an SSH client for Windows</LI>
+</UL>
+</LI>
+<LI>Tripwire saves message digests of your system files. Re-calculate
+ the digests and compare to saved values to detect any file changes.
+ There are several versions available:
+<UL>
+<LI><A href="http://www.tripwiresecurity.com/">commercial version</A></LI>
+<LI><A href="http://www.tripwire.org/">Open Source</A></LI>
+</UL>
+</LI>
+<LI><A href="http://www.snort.org">Snort</A> and<A href="http://www.lids.org">
+ LIDS</A> are intrusion detection system for Linux</LI>
+<LI><A href="http://www.fish.com/~zen/satan/satan.html">SATAN</A> System
+ Administrators Tool for Analysing Networks</LI>
+<LI><A href="http://www.insecure.org/nmap/">NMAP</A> Network Mapper</LI>
+<LI><A href="ftp://ftp.porcupine.org/pub/security/index.html">Wietse
+ Venema's page</A> with various tools</LI>
+<LI><A href="http://ita.ee.lbl.gov/index.html">Internet Traffic Archive</A>
+, various tools to analyze network traffic, mostly scripts to organise
+ and format tcpdump(8) output for specific purposes</LI>
+<LI><A name="ssmail">ssmail -- sendmail patched to do</A><A href="#carpediem">
+ opportunistic encryption</A>
+<UL>
+<LI><A href="http://www.home.aone.net.au/qualcomm/">web page</A> with
+ links to code and to a Usenix paper describing it, in PDF</LI>
+</UL>
+</LI>
+<LI><A href="http://www.openca.org/">Open CA</A> project to develop a
+ freely distributed<A href="#CA"> Certification Authority</A> for
+ building a open<A href="#PKI"> Public Key Infrastructure</A>.</LI>
+</UL>
+<H3><A name="people">Links to home pages</A></H3>
+<P>David Wagner at Berkeley provides a set of links to<A href="http://www.cs.berkeley.edu/~daw/people/crypto.html">
+ home pages</A> of cryptographers, cypherpunks and computer security
+ people.</P>
+<HR>
+<H1><A name="ourgloss">Glossary for the Linux FreeS/WAN project</A></H1>
+<P>Entries are in alphabetical order. Some entries are only one line or
+ one paragraph long. Others run to several paragraphs. I have tried to
+ put the essential information in the first paragraph so you can skip
+ the other paragraphs if that seems appropriate.</P>
+<HR>
+<H2><A name="jump">Jump to a letter in the glossary</A></H2>
+<CENTER> <BIG><B><A href="#0">numeric</A><A href="#A"> A</A><A href="#B">
+ B</A><A href="#C"> C</A><A href="#D"> D</A><A href="#E"> E</A><A href="#F">
+ F</A><A href="#G"> G</A><A href="#H"> H</A><A href="#I"> I</A><A href="#J">
+ J</A><A href="#K"> K</A><A href="#L"> L</A><A href="#M"> M</A><A href="#N">
+ N</A><A href="#O"> O</A><A href="#P"> P</A><A href="#Q"> Q</A><A href="#R">
+ R</A><A href="#S"> S</A><A href="#T"> T</A><A href="#U"> U</A><A href="#V">
+ V</A><A href="#W"> W</A><A href="#X"> X</A><A href="#Y"> Y</A><A href="#Z">
+ Z</A></B></BIG></CENTER>
+<HR>
+<H2><A name="gloss">Other glossaries</A></H2>
+<P>Other glossaries which overlap this one include:</P>
+<UL>
+<LI>The VPN Consortium's glossary of<A href="http://www.vpnc.org/terms.html">
+ VPN terms</A>.</LI>
+<LI>glossary portion of the<A href="http://www.rsa.com/rsalabs/faq/B.html">
+ Cryptography FAQ</A></LI>
+<LI>an extensive crytographic glossary on<A href="http://www.ciphersbyritter.com/GLOSSARY.HTM">
+ Terry Ritter's</A> page.</LI>
+<LI>The<A href="#NSA"> NSA</A>'s<A href="http://www.sans.org/newlook/resources/glossary.htm">
+ glossary of computer security</A> on the<A href="http://www.sans.org">
+ SANS Institute</A> site.</LI>
+<LI>a small glossary for Internet Security at<A href="http://www5.zdnet.com/pcmag/pctech/content/special/glossaries/internetsecurity.html">
+ PC magazine</A></LI>
+<LI>The<A href="http://www.visi.com/crypto/inet-crypto/glossary.html">
+ glossary</A> from Richard Smith's book<A href="#Smith"> Internet
+ Cryptography</A></LI>
+</UL>
+<P>Several Internet glossaries are available as RFCs:</P>
+<UL>
+<LI><A href="http://www.rfc-editor.org/rfc/rfc1208.txt">Glossary of
+ Networking Terms</A></LI>
+<LI><A href="http://www.rfc-editor.org/rfc/rfc1983.txt">Internet User's
+ Glossary</A></LI>
+<LI><A href="http://www.rfc-editor.org/rfc/rfc2828.txt">Internet
+ Security Glossary</A></LI>
+</UL>
+<P>More general glossary or dictionary information:</P>
+<UL>
+<LI>Free Online Dictionary of Computing (FOLDOC)
+<UL>
+<LI><A href="http://www.nightflight.com/foldoc">North America</A></LI>
+<LI><A href="http://wombat.doc.ic.ac.uk/foldoc/index.html">Europe</A></LI>
+<LI><A href="http://www.nue.org/foldoc/index.html">Japan</A></LI>
+</UL>
+<P>There are many more mirrors of this dictionary.</P>
+</LI>
+<LI>The Jargon File, the definitive resource for hacker slang and
+ folklore
+<UL>
+<LI><A href="http://www.netmeg.net/jargon">North America</A></LI>
+<LI><A href="http://info.wins.uva.nl/~mes/jargon/">Holland</A></LI>
+<LI><A href="http://www.tuxedo.org/~esr/jargon">home page</A></LI>
+</UL>
+<P>There are also many mirrors of this. See the home page for a list.</P>
+</LI>
+<LI>A general<A href="http://www.trinity.edu/~rjensen/245glosf.htm#Navigate">
+ technology glossary</A></LI>
+<LI>An<A href="http://www.yourdictionary.com/"> online dictionary
+ resource page</A> with pointers to many dictionaries for many languages</LI>
+<LI>A<A href="http://www.onelook.com/"> search engine</A> that accesses
+ several hundred online dictionaries</LI>
+<LI>O'Reilly<A href="http://www.ora.com/reference/dictionary/">
+ Dictionary of PC Hardware and Data Communications Terms</A></LI>
+<LI><A href="http://www.FreeSoft.org/CIE/index.htm">Connected</A>
+ Internet encyclopedia</LI>
+<LI><A href="http://www.whatis.com/">whatis.com</A></LI>
+</UL>
+<HR>
+<H2><A name="definitions">Definitions</A></H2>
+<DL>
+<DT><A name="0">0</A></DT>
+<DT><A name="3DES">3DES (Triple DES)</A></DT>
+<DD>Using three<A href="#DES"> DES</A> encryptions on a single data
+ block, with at least two different keys, to get higher security than is
+ available from a single DES pass. The three-key version of 3DES is the
+ default encryption algorithm for<A href="#FreeSWAN"> Linux FreeS/WAN</A>
+.
+<P><A href="#IPSEC">IPsec</A> always does 3DES with three different
+ keys, as required by RFC 2451. For an explanation of the two-key
+ variant, see<A href="#2key"> two key triple DES</A>. Both use an<A href="#EDE">
+ EDE</A> encrypt-decrypt-encrpyt sequence of operations.</P>
+<P>Single<A href="#DES"> DES</A> is<A href="#desnotsecure"> insecure</A>
+.</P>
+<P>Double DES is ineffective. Using two 56-bit keys, one might expect an
+ attacker to have to do 2<SUP>112</SUP> work to break it. In fact, only
+ 2<SUP>57</SUP> work is required with a<A href="#meet">
+ meet-in-the-middle attack</A>, though a large amount of memory is also
+ required. Triple DES is vulnerable to a similar attack, but that just
+ reduces the work factor from the 2<SUP>168</SUP> one might expect to 2<SUP>
+112</SUP>. That provides adequate protection against<A href="#brute">
+ brute force</A> attacks, and no better attack is known.</P>
+<P>3DES can be somewhat slow compared to other ciphers. It requires
+ three DES encryptions per block. DES was designed for hardware
+ implementation and includes some operations which are difficult in
+ software. However, the speed we get is quite acceptable for many uses.
+ See our<A href="performance.html"> performance</A> document for
+ details.</P>
+</DD>
+<DT><A name="A">A</A></DT>
+<DT><A name="active">Active attack</A></DT>
+<DD>An attack in which the attacker does not merely eavesdrop (see<A href="#passive">
+ passive attack</A>) but takes action to change, delete, reroute, add,
+ forge or divert data. Perhaps the best-known active attack is<A href="#middle">
+ man-in-the-middle</A>. In general,<A href="#authentication">
+ authentication</A> is a useful defense against active attacks.</DD>
+<DT><A name="AES">AES</A></DT>
+<DD>The<B> A</B>dvanced<B> E</B>ncryption<B> S</B>tandard -- a new<A href="#block">
+ block cipher</A> standard to replace<A href="#desnotsecure"> DES</A> --
+ developed by<A href="#NIST"> NIST</A>, the US National Institute of
+ Standards and Technology. DES used 64-bit blocks and a 56-bit key. AES
+ ciphers use a 128-bit block and 128, 192 or 256-bit keys. The larger
+ block size helps resist<A href="#birthday"> birthday attacks</A> while
+ the large key size prevents<A href="#brute"> brute force attacks</A>.
+<P>Fifteen proposals meeting NIST's basic criteria were submitted in
+ 1998 and subjected to intense discussion and analysis, &quot;round one&quot;
+ evaluation. In August 1999, NIST narrowed the field to five &quot;round two&quot;
+ candidates:</P>
+<UL>
+<LI><A href="http://www.research.ibm.com/security/mars.html">Mars</A>
+ from IBM</LI>
+<LI><A href="http://www.rsa.com/rsalabs/aes/">RC6</A> from RSA</LI>
+<LI><A href="http://www.esat.kuleuven.ac.be/~rijmen/rijndael/">Rijndael</A>
+ from two Belgian researchers</LI>
+<LI><A href="http://www.cl.cam.ac.uk/~rja14/serpent.html">Serpent</A>, a
+ British-Norwegian-Israeli collaboration</LI>
+<LI><A href="http://www.counterpane.com/twofish.html">Twofish</A> from
+ the consulting firm<A href="http://www.counterpane.com"> Counterpane</A>
+</LI>
+</UL>
+<P>Three of the five finalists -- Rijndael, Serpent and Twofish -- have
+ completely open licenses.</P>
+<P>In October 2000, NIST announced the winner -- Rijndael.</P>
+<P>For more information, see:</P>
+<UL>
+<LI>NIST's<A href="http://csrc.nist.gov/encryption/aes/aes_home.htm">
+ AES home page</A></LI>
+<LI>the Block Cipher Lounge<A href="http://www.ii.uib.no/~larsr/aes.html">
+ AES page</A></LI>
+<LI>Brian Gladman's<A href="http://fp.gladman.plus.com/cryptography_technology/index.htm">
+ code and benchmarks</A></LI>
+<LI>Helger Lipmaa's<A href="http://www.tcs.hut.fi/~helger/aes/"> survey
+ of implementations</A></LI>
+</UL>
+<P>AES will be added to a future release of<A href="#FreeSWAN"> Linux
+ FreeS/WAN</A>. Likely we will add all three of the finalists with good
+ licenses. User-written<A href="#patch"> AES patches</A> are already
+ available.</P>
+<P>Adding AES may also require adding stronger hashes,<A href="#SHA-256">
+ SHA-256, SHA-384 and SHA-512</A>.</P>
+</DD>
+<DT><A name="AH">AH</A></DT>
+<DD>The<A href="#IPSEC"> IPsec</A><B> A</B>uthentication<B> H</B>eader,
+ added after the IP header. For details, see our<A href="#AH.ipsec">
+ IPsec</A> document and/or RFC 2402.</DD>
+<DT><A name="alicebob">Alice and Bob</A></DT>
+<DD>A and B, the standard example users in writing on cryptography and
+ coding theory. Carol and Dave join them for protocols which require
+ more players.
+<P>Bruce Schneier extends these with many others such as Eve the
+ Eavesdropper and Victor the Verifier. His extensions seem to be in the
+ process of becoming standard as well. See page 23 of<A href="#schneier">
+ Applied Cryptography</A></P>
+<P>Alice and Bob have an amusing<A href="http://www.conceptlabs.co.uk/alicebob.html">
+ biography</A> on the web.</P>
+</DD>
+<DT>ARPA</DT>
+<DD>see<A href="#DARPA"> DARPA</A></DD>
+<DT><A name="ASIO">ASIO</A></DT>
+<DD>Australian Security Intelligence Organisation.</DD>
+<DT>Asymmetric cryptography</DT>
+<DD>See<A href="#public"> public key cryptography</A>.</DD>
+<DT><A name="authentication">Authentication</A></DT>
+<DD>Ensuring that a message originated from the expected sender and has
+ not been altered on route.<A href="#IPSEC"> IPsec</A> uses
+ authentication in two places:
+<UL>
+<LI>peer authentication, authenticating the players in<A href="#IKE">
+ IKE</A>'s<A href="#DH"> Diffie-Hellman</A> key exchanges to prevent<A href="#middle">
+ man-in-the-middle attacks</A>. This can be done in a number of ways.
+ The methods supported by FreeS/WAN are discussed in our<A href="#choose">
+ advanced configuration</A> document.</LI>
+<LI>packet authentication, authenticating packets on an established<A href="#SA">
+ SA</A>, either with a separate<A href="#AH"> authentication header</A>
+ or with the optional authentication in the<A href="#ESP"> ESP</A>
+ protocol. In either case, packet authentication uses a<A href="#HMAC">
+ hashed message athentication code</A> technique.</LI>
+</UL>
+<P>Outside IPsec, passwords are perhaps the most common authentication
+ mechanism. Their function is essentially to authenticate the person's
+ identity to the system. Passwords are generally only as secure as the
+ network they travel over. If you send a cleartext password over a
+ tapped phone line or over a network with a packet sniffer on it, the
+ security provided by that password becomes zero. Sending an encrypted
+ password is no better; the attacker merely records it and reuses it at
+ his convenience. This is called a<A href="#replay"> replay</A> attack.</P>
+<P>A common solution to this problem is a<A href="#challenge">
+ challenge-response</A> system. This defeats simple eavesdropping and
+ replay attacks. Of course an attacker might still try to break the
+ cryptographic algorithm used, or the<A href="#random"> random number</A>
+ generator.</P>
+</DD>
+<DT><A name="auto">Automatic keying</A></DT>
+<DD>A mode in which keys are automatically generated at connection
+ establisment and new keys automaically created periodically thereafter.
+ Contrast with<A href="#manual"> manual keying</A> in which a single
+ stored key is used.
+<P>IPsec uses the<A href="#DH"> Diffie-Hellman key exchange protocol</A>
+ to create keys. An<A href="#authentication"> authentication</A>
+ mechansim is required for this. FreeS/WAN normally uses<A href="#RSA">
+ RSA</A> for this. Other methods supported are discussed in our<A href="#choose">
+ advanced configuration</A> document.</P>
+<P>Having an attacker break the authentication is emphatically not a
+ good idea. An attacker that breaks authentication, and manages to
+ subvert some other network entities (DNS, routers or gateways), can use
+ a<A href="#middle"> man-in-the middle attack</A> to break the security
+ of your IPsec connections.</P>
+<P>However, having an attacker break the authentication in automatic
+ keying is not quite as bad as losing the key in manual keying.</P>
+<UL>
+<LI>An attacker who reads /etc/ipsec.conf and gets the keys for a
+ manually keyed connection can, without further effort, read all
+ messages encrypted with those keys, including any old messages he may
+ have archived.</LI>
+<LI>Automatic keying has a property called<A href="#PFS"> perfect
+ forward secrecy</A>. An attacker who breaks the authentication gets
+ none of the automatically generated keys and cannot immediately read
+ any messages. He has to mount a successful<A href="#middle">
+ man-in-the-middle attack</A> in real time before he can read anything.
+ He cannot read old archived messages at all and will not be able to
+ read any future messages not caught by man-in-the-middle tricks.</LI>
+</UL>
+<P>That said, the secrets used for authentication, stored in<A href="manpage.d/ipsec.secrets.5.html">
+ ipsec.secrets(5)</A>, should still be protected as tightly as
+ cryptographic keys.</P>
+</DD>
+<DT><A name="B">B</A></DT>
+<DT><A href="http://www.nortelnetworks.com">Bay Networks</A></DT>
+<DD>A vendor of routers, hubs and related products, now a subsidiary of
+ Nortel. Interoperation between their IPsec products and Linux FreeS/WAN
+ was problematic at last report; see our<A href="interop.html#bay">
+ interoperation</A> section.</DD>
+<DT><A name="benchmarks">benchmarks</A></DT>
+<DD>Our default block cipher,<A href="#3DES"> triple DES</A>, is slower
+ than many alternate ciphers that might be used. Speeds achieved,
+ however, seem adequate for many purposes. For example, the assembler
+ code from the<A href="#LIBDES"> LIBDES</A> library we use encrypts 1.6
+ megabytes per second on a Pentium 200, according to the test program
+ supplied with the library.
+<P>For more detail, see our document on<A href="performance.html">
+ FreeS/WAN performance</A>.</P>
+</DD>
+<DT><A name="BIND">BIND</A></DT>
+<DD><B>B</B>erkeley<B> I</B>nternet<B> N</B>ame<B> D</B>aemon, a widely
+ used implementation of<A href="#DNS"> DNS</A> (Domain Name Service).
+ See our bibliography for a<A href="#DNS"> useful reference</A>. See the<A
+href="http://www.isc.org/bind.html"> BIND home page</A> for more
+ information and the latest version.</DD>
+<DT><A name="birthday">Birthday attack</A></DT>
+<DD>A cryptographic attack based on the mathematics exemplified by the<A href="#paradox">
+ birthday paradox</A>. This math turns up whenever the question of two
+ cryptographic operations producing the same result becomes an issue:
+<UL>
+<LI><A href="#collision">collisions</A> in<A href="#digest"> message
+ digest</A> functions.</LI>
+<LI>identical output blocks from a<A href="#block"> block cipher</A></LI>
+<LI>repetition of a challenge in a<A href="#challenge">
+ challenge-response</A> system</LI>
+</UL>
+<P>Resisting such attacks is part of the motivation for:</P>
+<UL>
+<LI>hash algorithms such as<A href="#SHA"> SHA</A> and<A href="#RIPEMD">
+ RIPEMD-160</A> giving a 160-bit result rather than the 128 bits of<A href="#MD4">
+ MD4</A>,<A href="#MD5"> MD5</A> and<A href="#RIPEMD"> RIPEMD-128</A>.</LI>
+<LI><A href="#AES">AES</A> block ciphers using a 128-bit block instead
+ of the 64-bit block of most current ciphers</LI>
+<LI><A href="#IPSEC">IPsec</A> using a 32-bit counter for packets sent
+ on an<A href="#auto"> automatically keyed</A><A href="#SA"> SA</A> and
+ requiring that the connection always be rekeyed before the counter
+ overflows.</LI>
+</UL>
+</DD>
+<DT><A name="paradox">Birthday paradox</A></DT>
+<DD>Not really a paradox, just a rather counter-intuitive mathematical
+ fact. In a group of 23 people, the chance of a least one pair having
+ the same birthday is over 50%.
+<P>The second person has 1 chance in 365 (ignoring leap years) of
+ matching the first. If they don't match, the third person's chances of
+ matching one of them are 2/365. The 4th, 3/365, and so on. The total of
+ these chances grows more quickly than one might guess.</P>
+</DD>
+<DT><A name="block">Block cipher</A></DT>
+<DD>A<A href="#symmetric"> symmetric cipher</A> which operates on
+ fixed-size blocks of plaintext, giving a block of ciphertext for each.
+ Contrast with<A href="#stream"> stream cipher</A>. Block ciphers can be
+ used in various<A href="#mode"> modes</A> when multiple block are to be
+ encrypted.
+<P><A href="#DES">DES</A> is among the the best known and widely used
+ block ciphers, but is now obsolete. Its 56-bit key size makes it<A href="#desnotsecure">
+ highly insecure</A> today.<A href="#3DES"> Triple DES</A> is the
+ default block cipher for<A href="#FreeSWAN"> Linux FreeS/WAN</A>.</P>
+<P>The current generation of block ciphers -- such as<A href="#Blowfish">
+ Blowfish</A>,<A href="#CAST128"> CAST-128</A> and<A href="#IDEA"> IDEA</A>
+ -- all use 64-bit blocks and 128-bit keys. The next generation,<A href="#AES">
+ AES</A>, uses 128-bit blocks and supports key sizes up to 256 bits.</P>
+<P>The<A href="http://www.ii.uib.no/~larsr/bc.html"> Block Cipher Lounge</A>
+ web site has more information.</P>
+</DD>
+<DT><A name="Blowfish">Blowfish</A></DT>
+<DD>A<A href="#block"> block cipher</A> using 64-bit blocks and keys of
+ up to 448 bits, designed by<A href="#schneier"> Bruce Schneier</A> and
+ used in several products.
+<P>This is not required by the<A href="#IPSEC"> IPsec</A> RFCs and not
+ currently used in<A href="#FreeSWAN"> Linux FreeS/WAN</A>.</P>
+</DD>
+<DT><A name="brute">Brute force attack (exhaustive search)</A></DT>
+<DD>Breaking a cipher by trying all possible keys. This is always
+ possible in theory (except against a<A href="#OTP"> one-time pad</A>),
+ but it becomes practical only if the key size is inadequate. For an
+ important example, see our document on the<A href="#desnotsecure">
+ insecurity of DES</A> with its 56-bit key. For an analysis of key sizes
+ required to resist plausible brute force attacks, see<A href="http://www.counterpane.com/keylength.html">
+ this paper</A>.
+<P>Longer keys protect against brute force attacks. Each extra bit in
+ the key doubles the number of possible keys and therefore doubles the
+ work a brute force attack must do. A large enough key defeats<STRONG>
+ any</STRONG> brute force attack.</P>
+<P>For example, the EFF's<A href="#EFF"> DES Cracker</A> searches a
+ 56-bit key space in an average of a few days. Let us assume an attacker
+ that can find a 64-bit key (256 times harder) by brute force search in
+ a second (a few hundred thousand times faster). For a 96-bit key, that
+ attacker needs 2<SUP>32</SUP> seconds, about 135 years. Against a
+ 128-bit key, he needs 2<SUP>32</SUP> times that, over 500,000,000,000
+ years. Your data is then obviously secure against brute force attacks.
+ Even if our estimate of the attacker's speed is off by a factor of a
+ million, it still takes him over 500,000 years to crack a message.</P>
+<P>This is why</P>
+<UL>
+<LI>single<A href="#DES"> DES</A> is now considered<A href="#desnotsecure">
+ dangerously insecure</A></LI>
+<LI>all of the current generation of<A href="#block"> block ciphers</A>
+ use a 128-bit or longer key</LI>
+<LI><A href="#AES">AES</A> ciphers support keysizes 128, 192 and 256
+ bits</LI>
+<LI>any cipher we add to Linux FreeS/WAN will have<EM> at least</EM> a
+ 128-bit key</LI>
+</UL>
+<P><STRONG>Cautions:</STRONG>
+<BR><EM> Inadequate keylength always indicates a weak cipher</EM> but it
+ is important to note that<EM> adequate keylength does not necessarily
+ indicate a strong cipher</EM>. There are many attacks other than brute
+ force, and adequate keylength<EM> only</EM> guarantees resistance to
+ brute force. Any cipher, whatever its key size, will be weak if design
+ or implementation flaws allow other attacks.</P>
+<P>Also,<EM> once you have adequate keylength</EM> (somewhere around 90
+ or 100 bits),<EM> adding more key bits make no practical difference</EM>
+, even against brute force. Consider our 128-bit example above that
+ takes 500,000,000,000 years to break by brute force. We really don't
+ care how many zeroes there are on the end of that, as long as the
+ number remains ridiculously large. That is, we don't care exactly how
+ large the key is as long as it is large enough.</P>
+<P>There may be reasons of convenience in the design of the cipher to
+ support larger keys. For example<A href="#Blowfish"> Blowfish</A>
+ allows up to 448 bits and<A href="#RC4"> RC4</A> up to 2048, but beyond
+ 100-odd bits it makes no difference to practical security.</P>
+</DD>
+<DT>Bureau of Export Administration</DT>
+<DD>see<A href="#BXA"> BXA</A></DD>
+<DT><A name="BXA">BXA</A></DT>
+<DD>The US Commerce Department's<B> B</B>ureau of E<B>x</B>port<B> A</B>
+dministration which administers the<A href="#EAR"> EAR</A> Export
+ Administration Regulations controling the export of, among other
+ things, cryptography.</DD>
+<DT><A name="C">C</A></DT>
+<DT><A name="CA">CA</A></DT>
+<DD><B>C</B>ertification<B> A</B>uthority, an entity in a<A href="#PKI">
+ public key infrastructure</A> that can certify keys by signing them.
+ Usually CAs form a hierarchy. The top of this hierarchy is called the<A href="#rootCA">
+ root CA</A>.
+<P>See<A href="#web"> Web of Trust</A> for an alternate model.</P>
+</DD>
+<DT><A name="CAST128">CAST-128</A></DT>
+<DD>A<A href="#block"> block cipher</A> using 64-bit blocks and 128-bit
+ keys, described in RFC 2144 and used in products such as<A href="#Entrust">
+ Entrust</A> and recent versions of<A href="#PGP"> PGP</A>.
+<P>This is not required by the<A href="#IPSEC"> IPsec</A> RFCs and not
+ currently used in<A href="#FreeSWAN"> Linux FreeS/WAN</A>.</P>
+</DD>
+<DT>CAST-256</DT>
+<DD><A href="#Entrust">Entrust</A>'s candidate cipher for the<A href="#AES">
+ AES standard</A>, largely based on the<A href="#CAST128"> CAST-128</A>
+ design.</DD>
+<DT><A name="CBC">CBC mode</A></DT>
+<DD><B>C</B>ipher<B> B</B>lock<B> C</B>haining<A href="#mode"> mode</A>,
+ a method of using a<A href="#block"> block cipher</A> in which for each
+ block except the first, the result of the previous encryption is XORed
+ into the new block before it is encrypted. CBC is the mode used in<A href="#IPSEC">
+ IPsec</A>.
+<P>An<A href="#IV"> initialisation vector</A> (IV) must be provided. It
+ is XORed into the first block before encryption. The IV need not be
+ secret but should be different for each message and unpredictable.</P>
+</DD>
+<DT><A name="CIDR">CIDR</A></DT>
+<DD><B>C</B>lassless<B> I</B>nter-<B>D</B>omain<B> R</B>outing, an
+ addressing scheme used to describe networks not restricted to the old
+ Class A, B, and C sizes. A CIDR block is written<VAR> address</VAR>/<VAR>
+mask</VAR>, where<VAR> address</VAR> is a 32-bit Internet address. The
+ first<VAR> mask</VAR> bits of<VAR> address</VAR> are part of the
+ gateway address, while the remaining bits designate other host
+ addresses. For example, the CIDR block 192.0.2.96/27 describes a
+ network with gateway 192.0.2.96, hosts 192.0.2.96 through 192.0.2.126
+ and broadcast 192.0.2.127.
+<P>FreeS/WAN policy group files accept CIDR blocks of the format<VAR>
+ address</VAR>/[<VAR>mask</VAR>], where<VAR> address</VAR> may take the
+ form<VAR> name.domain.tld</VAR>. An absent<VAR> mask</VAR> is assumed
+ to be /32.</P>
+</DD>
+<DT>Certification Authority</DT>
+<DD>see<A href="#CA"> CA</A></DD>
+<DT><A name="challenge">Challenge-response authentication</A></DT>
+<DD>An<A href="#authentication"> authentication</A> system in which one
+ player generates a<A href="#random"> random number</A>, encrypts it and
+ sends the result as a challenge. The other player decrypts and sends
+ back the result. If the result is correct, that proves to the first
+ player that the second player knew the appropriate secret, required for
+ the decryption. Variations on this technique exist using<A href="#public">
+ public key</A> or<A href="#symmetric"> symmetric</A> cryptography. Some
+ provide two-way authentication, assuring each player of the other's
+ identity.
+<P>This is more secure than passwords against two simple attacks:</P>
+<UL>
+<LI>If cleartext passwords are sent across the wire (e.g. for telnet),
+ an eavesdropper can grab them. The attacker may even be able to break
+ into other systems if the user has chosen the same password for them.</LI>
+<LI>If an encrypted password is sent, an attacker can record the
+ encrypted form and use it later. This is called a replay attack.</LI>
+</UL>
+<P>A challenge-response system never sends a password, either cleartext
+ or encrypted. An attacker cannot record the response to one challenge
+ and use it as a response to a later challenge. The random number is
+ different each time.</P>
+<P>Of course an attacker might still try to break the cryptographic
+ algorithm used, or the<A href="#random"> random number</A> generator.</P>
+</DD>
+<DT><A name="mode">Cipher Modes</A></DT>
+<DD>Different ways of using a block cipher when encrypting multiple
+ blocks.
+<P>Four standard modes were defined for<A href="#DES"> DES</A> in<A href="#FIPS">
+ FIPS</A> 81. They can actually be applied with any block cipher.</P>
+<TABLE><TBODY></TBODY>
+<TR><TD></TD><TD><A href="#ECB">ECB</A></TD><TD>Electronic CodeBook</TD><TD>
+encrypt each block independently</TD></TR>
+<TR><TD></TD><TD><A href="#CBC">CBC</A></TD><TD>Cipher Block Chaining
+<BR></TD><TD>XOR previous block ciphertext into new block plaintext
+ before encrypting new block</TD></TR>
+<TR><TD></TD><TD>CFB</TD><TD>Cipher FeedBack</TD><TD></TD></TR>
+<TR><TD></TD><TD>OFB</TD><TD>Output FeedBack</TD><TD></TD></TR>
+</TABLE>
+<P><A href="#IPSEC">IPsec</A> uses<A href="#CBC"> CBC</A> mode since
+ this is only marginally slower than<A href="#ECB"> ECB</A> and is more
+ secure. In ECB mode the same plaintext always encrypts to the same
+ ciphertext, unless the key is changed. In CBC mode, this does not
+ occur.</P>
+<P>Various other modes are also possible, but none of them are used in
+ IPsec.</P>
+</DD>
+<DT><A name="ciphertext">Ciphertext</A></DT>
+<DD>The encrypted output of a cipher, as opposed to the unencrypted<A href="#plaintext">
+ plaintext</A> input.</DD>
+<DT><A href="http://www.cisco.com">Cisco</A></DT>
+<DD>A vendor of routers, hubs and related products. Their IPsec products
+ interoperate with Linux FreeS/WAN; see our<A href="#cisco"> interop</A>
+ section.</DD>
+<DT><A name="client">Client</A></DT>
+<DD>This term has at least two distinct uses in discussing IPsec:
+<UL>
+<LI>The<STRONG> clients of an IPsec gateway</STRONG> are the machines it
+ protects, typically on one or more subnets behind the gateway. In this
+ usage, all the machines on an office network are clients of that
+ office's IPsec gateway. Laptop or home machines connecting to the
+ office, however, are<EM> not</EM> clients of that gateway. They are
+ remote gateways, running the other end of an IPsec connection. Each of
+ them is also its own client.</LI>
+<LI><STRONG>IPsec client software</STRONG> is used to describe software
+ which runs on various standalone machines to let them connect to IPsec
+ networks. In this usage, a laptop or home machine connecting to the
+ office is a client, and the office gateway is the server.</LI>
+</UL>
+<P>We generally use the term in the first sense. Vendors of Windows
+ IPsec solutions often use it in the second. See this<A href="interop.html#client.server">
+ discussion</A>.</P>
+</DD>
+<DT><A name="cc">Common Criteria</A></DT>
+<DD>A set of international security classifications which are replacing
+ the old US<A href="#rainbow"> Rainbow Book</A> standards and similar
+ standards in other countries.
+<P>Web references include this<A href="http://csrc.nist.gov/cc"> US
+ government site</A> and this<A href="http://www.commoncriteria.org">
+ global home page</A>.</P>
+</DD>
+<DT>Conventional cryptography</DT>
+<DD>See<A href="#symmetric"> symmetric cryptography</A></DD>
+<DT><A name="collision">Collision resistance</A></DT>
+<DD>The property of a<A href="#digest"> message digest</A> algorithm
+ which makes it hard for an attacker to find or construct two inputs
+ which hash to the same output.</DD>
+<DT>Copyleft</DT>
+<DD>see GNU<A href="#GPL"> General Public License</A></DD>
+<DT><A name="CSE">CSE</A></DT>
+<DD><A href="http://www.cse-cst.gc.ca/">Communications Security
+ Establishment</A>, the Canadian organisation for<A href="#SIGINT">
+ signals intelligence</A>.</DD>
+<DT><A name="D">D</A></DT>
+<DT><A name="DARPA">DARPA (sometimes just ARPA)</A></DT>
+<DD>The US government's<B> D</B>efense<B> A</B>dvanced<B> R</B>esearch<B>
+ P</B>rojects<B> A</B>gency. Projects they have funded over the years
+ have included the Arpanet which evolved into the Internet, the TCP/IP
+ protocol suite (as a replacement for the original Arpanet suite), the
+ Berkeley 4.x BSD Unix projects, and<A href="#SDNS"> Secure DNS</A>.
+<P>For current information, see their<A href="http://www.darpa.mil/ito">
+ web site</A>.</P>
+</DD>
+<DT><A name="DOS">Denial of service (DoS) attack</A></DT>
+<DD>An attack that aims at denying some service to legitimate users of a
+ system, rather than providing a service to the attacker.
+<UL>
+<LI>One variant is a flooding attack, overwhelming the system with too
+ many packets, to much email, or whatever.</LI>
+<LI>A closely related variant is a resource exhaustion attack. For
+ example, consider a &quot;TCP SYN flood&quot; attack. Setting up a TCP connection
+ involves a three-packet exchange:
+<UL>
+<LI>Initiator: Connection please (SYN)</LI>
+<LI>Responder: OK (ACK)</LI>
+<LI>Initiator: OK here too</LI>
+</UL>
+<P>If the attacker puts bogus source information in the first packet,
+ such that the second is never delivered, the responder may wait a long
+ time for the third to come back. If responder has already allocated
+ memory for the connection data structures, and if many of these bogus
+ packets arrive, the responder may run out of memory.</P>
+</LI>
+<LI>Another variant is to feed the system undigestible data, hoping to
+ make it sick. For example, IP packets are limited in size to 64K bytes
+ and a fragment carries information on where it starts within that 64K
+ and how long it is. The &quot;ping of death&quot; delivers fragments that say,
+ for example, that they start at 60K and are 20K long. Attempting to
+ re-assemble these without checking for overflow can be fatal.</LI>
+</UL>
+<P>The two example attacks discussed were both quite effective when
+ first discovered, capable of crashing or disabling many operating
+ systems. They were also well-publicised, and today far fewer systems
+ are vulnerable to them.</P>
+</DD>
+<DT><A name="DES">DES</A></DT>
+<DD>The<B> D</B>ata<B> E</B>ncryption<B> S</B>tandard, a<A href="#block">
+ block cipher</A> with 64-bit blocks and a 56-bit key. Probably the most
+ widely used<A href="#symmetric"> symmetric cipher</A> ever devised. DES
+ has been a US government standard for their own use (only for
+ unclassified data), and for some regulated industries such as banking,
+ since the late 70's. It is now being replaced by<A href="#AES"> AES</A>
+.
+<P><A href="#desnotsecure">DES is seriously insecure against current
+ attacks.</A></P>
+<P><A href="#FreeSWAN">Linux FreeS/WAN</A> does not include DES, even
+ though the RFCs specify it.<B> We strongly recommend that single DES
+ not be used.</B></P>
+<P>See also<A href="#3DES"> 3DES</A> and<A href="#DESX"> DESX</A>,
+ stronger ciphers based on DES.</P>
+</DD>
+<DT><A name="DESX">DESX</A></DT>
+<DD>An improved<A href="#DES"> DES</A> suggested by Ron Rivest of RSA
+ Data Security. It XORs extra key material into the text before and
+ after applying the DES cipher.
+<P>This is not required by the<A href="#IPSEC"> IPsec</A> RFCs and not
+ currently used in<A href="#FreeSWAN"> Linux FreeS/WAN</A>. DESX would
+ be the easiest additional transform to add; there would be very little
+ code to write. It would be much faster than 3DES and almost certainly
+ more secure than DES. However, since it is not in the RFCs other IPsec
+ implementations cannot be expected to have it.</P>
+</DD>
+<DT>DH</DT>
+<DD>see<A href="#DH"> Diffie-Hellman</A></DD>
+<DT><A name="DHCP">DHCP</A></DT>
+<DD><STRONG>D</STRONG>ynamic<STRONG> H</STRONG>ost<STRONG> C</STRONG>
+onfiguration<STRONG> P</STRONG>rotocol, a method of assigning<A href="#dynamic">
+ dynamic IP addresses</A>, and providing additional information such as
+ addresses of DNS servers and of gateways. See this<A href="http://www.dhcp.org">
+ DHCP resource page.</A></DD>
+<DT><A name="DH">Diffie-Hellman (DH) key exchange protocol</A></DT>
+<DD>A protocol that allows two parties without any initial shared secret
+ to create one in a manner immune to eavesdropping. Once they have done
+ this, they can communicate privately by using that shared secret as a
+ key for a block cipher or as the basis for key exchange.
+<P>The protocol is secure against all<A href="#passive"> passive attacks</A>
+, but it is not at all resistant to active<A href="#middle">
+ man-in-the-middle attacks</A>. If a third party can impersonate Bob to
+ Alice and vice versa, then no useful secret can be created.
+ Authentication of the participants is a prerequisite for safe
+ Diffie-Hellman key exchange. IPsec can use any of several<A href="#authentication">
+ authentication</A> mechanisims. Those supported by FreeS/WAN are
+ discussed in our<A href="#choose"> configuration</A> section.</P>
+<P>The Diffie-Hellman key exchange is based on the<A href="#dlog">
+ discrete logarithm</A> problem and is secure unless someone finds an
+ efficient solution to that problem.</P>
+<P>Given a prime<VAR> p</VAR> and generator<VAR> g</VAR> (explained
+ under<A href="#dlog"> discrete log</A> below), Alice:</P>
+<UL>
+<LI>generates a random number<VAR> a</VAR></LI>
+<LI>calculates<VAR> A = g^a modulo p</VAR></LI>
+<LI>sends<VAR> A</VAR> to Bob</LI>
+</UL>
+<P>Meanwhile Bob:</P>
+<UL>
+<LI>generates a random number<VAR> b</VAR></LI>
+<LI>calculates<VAR> B = g^b modulo p</VAR></LI>
+<LI>sends<VAR> B</VAR> to Alice</LI>
+</UL>
+<P>Now Alice and Bob can both calculate the shared secret<VAR> s =
+ g^(ab)</VAR>. Alice knows<VAR> a</VAR> and<VAR> B</VAR>, so she
+ calculates<VAR> s = B^a</VAR>. Bob knows<VAR> A</VAR> and<VAR> b</VAR>
+ so he calculates<VAR> s = A^b</VAR>.</P>
+<P>An eavesdropper will know<VAR> p</VAR> and<VAR> g</VAR> since these
+ are made public, and can intercept<VAR> A</VAR> and<VAR> B</VAR> but,
+ short of solving the<A href="#dlog"> discrete log</A> problem, these do
+ not let him or her discover the secret<VAR> s</VAR>.</P>
+</DD>
+<DT><A name="signature">Digital signature</A></DT>
+<DD>Sender:
+<UL>
+<LI>calculates a<A href="#digest"> message digest</A> of a document</LI>
+<LI>encrypts the digest with his or her private key, using some<A href="#public">
+ public key cryptosystem</A>.</LI>
+<LI>attaches the encrypted digest to the document as a signature</LI>
+</UL>
+<P>Receiver:</P>
+<UL>
+<LI>calculates a digest of the document (not including the signature)</LI>
+<LI>decrypts the signature with the signer's public key</LI>
+<LI>verifies that the two results are identical</LI>
+</UL>
+<P>If the public-key system is secure and the verification succeeds,
+ then the receiver knows</P>
+<UL>
+<LI>that the document was not altered between signing and verification</LI>
+<LI>that the signer had access to the private key</LI>
+</UL>
+<P>Such an encrypted message digest can be treated as a signature since
+ it cannot be created without<EM> both</EM> the document<EM> and</EM>
+ the private key which only the sender should possess. The<A href="#legal">
+ legal issues</A> are complex, but several countries are moving in the
+ direction of legal recognition for digital signatures.</P>
+</DD>
+<DT><A name="dlog">discrete logarithm problem</A></DT>
+<DD>The problem of finding logarithms in a finite field. Given a field
+ defintion (such definitions always include some operation analogous to
+ multiplication) and two numbers, a base and a target, find the power
+ which the base must be raised to in order to yield the target.
+<P>The discrete log problem is the basis of several cryptographic
+ systems, including the<A href="#DH"> Diffie-Hellman</A> key exchange
+ used in the<A href="#IKE"> IKE</A> protocol. The useful property is
+ that exponentiation is relatively easy but the inverse operation,
+ finding the logarithm, is hard. The cryptosystems are designed so that
+ the user does only easy operations (exponentiation in the field) but an
+ attacker must solve the hard problem (discrete log) to crack the
+ system.</P>
+<P>There are several variants of the problem for different types of
+ field. The IKE/Oakley key determination protocol uses two variants,
+ either over a field modulo a prime or over a field defined by an
+ elliptic curve. We give an example modulo a prime below. For the
+ elliptic curve version, consult an advanced text such as<A href="#handbook">
+ Handbook of Applied Cryptography</A>.</P>
+<P>Given a prime<VAR> p</VAR>, a generator<VAR> g</VAR> for the field
+ modulo that prime, and a number<VAR> x</VAR> in the field, the problem
+ is to find<VAR> y</VAR> such that<VAR> g^y = x</VAR>.</P>
+<P>For example, let p = 13. The field is then the integers from 0 to 12.
+ Any integer equals one of these modulo 13. That is, the remainder when
+ any integer is divided by 13 must be one of these.</P>
+<P>2 is a generator for this field. That is, the powers of two modulo 13
+ run through all the non-zero numbers in the field. Modulo 13 we have:</P>
+<PRE>          y      x
+        2^0  ==  1
+        2^1  ==  2
+        2^2  ==  4
+        2^3  ==  8
+        2^4  ==  3 that is, the remainder from 16/13 is 3
+        2^5  ==  6          the remainder from 32/13 is 6
+        2^6  == 12 and so on
+        2^7  == 11
+        2^8  ==  9
+        2^9  ==  5
+        2^10 == 10
+        2^11 ==  7
+        2^12 ==  1</PRE>
+<P>Exponentiation in such a field is not difficult. Given, say,<NOBR><VAR>
+ y = 11</VAR>,calculating<NOBR><VAR> x = 7</VAR>is straightforward. One
+ method is just to calculate<NOBR><VAR> 2^11 = 2048</VAR>,then<NOBR><VAR>
+ 2048 mod 13 == 7</VAR>.When the field is modulo a large prime (say a
+ few 100 digits) you need a silghtly cleverer method and even that is
+ moderately expensive in computer time, but the calculation is still not
+ problematic in any basic way.</P>
+<P>The discrete log problem is the reverse. In our example, given<NOBR><VAR>
+ x = 7</VAR>,find the logarithm<NOBR><VAR> y = 11</VAR>.When the field
+ is modulo a large prime (or is based on a suitable elliptic curve),
+ this is indeed problematic. No solution method that is not
+ catastrophically expensive is known. Quite a few mathematicians have
+ tackled this problem. No efficient method has been found and
+ mathematicians do not expect that one will be. It seems likely no
+ efficient solution to either of the main variants the discrete log
+ problem exists.</P>
+<P>Note, however, that no-one has proven such methods do not exist. If a
+ solution to either variant were found, the security of any crypto
+ system using that variant would be destroyed. This is one reason<A href="#IKE">
+ IKE</A> supports two variants. If one is broken, we can switch to the
+ other.</P>
+</DD>
+<DT><A name="discretionary">discretionary access control</A></DT>
+<DD>access control mechanisms controlled by the user, for example Unix
+ rwx file permissions. These contrast with<A href="#mandatory">
+ mandatory access controls</A>.</DD>
+<DT><A name="DNS">DNS</A></DT>
+<DD><B>D</B>omain<B> N</B>ame<B> S</B>ervice, a distributed database
+ through which names are associated with numeric addresses and other
+ information in the Internet Protocol Suite. See also the<A href="#dns.background">
+ DNS background</A> section of our documentation.</DD>
+<DT>DOS attack</DT>
+<DD>see<A href="#DOS"> Denial Of Service</A> attack</DD>
+<DT><A name="dynamic">dynamic IP address</A></DT>
+<DD>an IP address which is automatically assigned, either by<A href="#DHCP">
+ DHCP</A> or by some protocol such as<A href="#PPP"> PPP</A> or<A href="#PPPoE">
+ PPPoE</A> which the machine uses to connect to the Internet. This is
+ the opposite of a<A href="#static"> static IP address</A>, pre-set on
+ the machine itself.</DD>
+<DT><A name="E">E</A></DT>
+<DT><A name="EAR">EAR</A></DT>
+<DD>The US government's<B> E</B>xport<B> A</B>dministration<B> R</B>
+egulations, administered by the<A href="#BXA"> Bureau of Export
+ Administration</A>. These have replaced the earlier<A href="#ITAR">
+ ITAR</A> regulations as the controls on export of cryptography.</DD>
+<DT><A name="ECB">ECB mode</A></DT>
+<DD><B>E</B>lectronic<B> C</B>ode<B>B</B>ook mode, the simplest way to
+ use a block cipher. See<A href="#mode"> Cipher Modes</A>.</DD>
+<DT><A name="EDE">EDE</A></DT>
+<DD>The sequence of operations normally used in either the three-key
+ variant of<A href="#3DES"> triple DES</A> used in<A href="#IPSEC">
+ IPsec</A> or the<A href="#2key"> two-key</A> variant used in some other
+ systems.
+<P>The sequence is:</P>
+<UL>
+<LI><B>E</B>ncrypt with key1</LI>
+<LI><B>D</B>ecrypt with key2</LI>
+<LI><B>E</B>ncrypt with key3</LI>
+</UL>
+<P>For the two-key version, key1=key3.</P>
+<P>The &quot;advantage&quot; of this EDE order of operations is that it makes it
+ simple to interoperate with older devices offering only single DES. Set
+ key1=key2=key3 and you have the worst of both worlds, the overhead of
+ triple DES with the &quot;security&quot; of single DES. Since both the<A href="#desnotsecure">
+ security of single DES</A> and the overheads of triple DES are
+ seriously inferior to many other ciphers, this is a spectacularly
+ dubious &quot;advantage&quot;.</P>
+</DD>
+<DT><A name="Entrust">Entrust</A></DT>
+<DD>A Canadian company offerring enterprise<A href="#PKI"> PKI</A>
+ products using<A href="#CAST128"> CAST-128</A> symmetric crypto,<A href="#RSA">
+ RSA</A> public key and<A href="#X509"> X.509</A> directories.<A href="http://www.entrust.com">
+ Web site</A></DD>
+<DT><A name="EFF">EFF</A></DT>
+<DD><A href="http://www.eff.org">Electronic Frontier Foundation</A>, an
+ advocacy group for civil rights in cyberspace.</DD>
+<DT><A name="encryption">Encryption</A></DT>
+<DD>Techniques for converting a readable message (<A href="#plaintext">
+plaintext</A>) into apparently random material (<A href="#ciphertext">
+ciphertext</A>) which cannot be read if intercepted. A key is required
+ to read the message.
+<P>Major variants include<A href="#symmetric"> symmetric</A> encryption
+ in which sender and receiver use the same secret key and<A href="#public">
+ public key</A> methods in which the sender uses one of a matched pair
+ of keys and the receiver uses the other. Many current systems,
+ including<A href="#IPSEC"> IPsec</A>, are<A href="#hybrid"> hybrids</A>
+ combining the two techniques.</P>
+</DD>
+<DT><A name="ESP">ESP</A></DT>
+<DD><B>E</B>ncapsulated<B> S</B>ecurity<B> P</B>ayload, the<A href="#IPSEC">
+ IPsec</A> protocol which provides<A href="#encryption"> encryption</A>.
+ It can also provide<A href="#authentication"> authentication</A>
+ service and may be used with null encryption (which we do not
+ recommend). For details see our<A href="#ESP.ipsec"> IPsec</A> document
+ and/or RFC 2406.</DD>
+<DT><A name="#extruded">Extruded subnet</A></DT>
+<DD>A situation in which something IP sees as one network is actually in
+ two or more places.
+<P>For example, the Internet may route all traffic for a particular
+ company to that firm's corporate gateway. It then becomes the company's
+ problem to get packets to various machines on their<A href="#subnet">
+ subnets</A> in various departments. They may decide to treat a branch
+ office like a subnet, giving it IP addresses &quot;on&quot; their corporate net.
+ This becomes an extruded subnet.</P>
+<P>Packets bound for it are delivered to the corporate gateway, since as
+ far as the outside world is concerned, that subnet is part of the
+ corporate network. However, instead of going onto the corporate LAN (as
+ they would for, say, the accounting department) they are then
+ encapsulated and sent back onto the Internet for delivery to the branch
+ office.</P>
+<P>For information on doing this with Linux FreeS/WAN, look in our<A href="#extruded.config">
+ advanced configuration</A> section.</P>
+</DD>
+<DT>Exhaustive search</DT>
+<DD>See<A href="#brute"> brute force attack</A>.</DD>
+<DT><A name="F">F</A></DT>
+<DT><A name="FIPS">FIPS</A></DT>
+<DD><B>F</B>ederal<B> I</B>nformation<B> P</B>rocessing<B> S</B>tandard,
+ the US government's standards for products it buys. These are issued by<A
+href="#NIST"> NIST</A>. Among other things,<A href="#DES"> DES</A> and<A href="#SHA">
+ SHA</A> are defined in FIPS documents. NIST have a<A href="http://www.itl.nist.gov/div897/pubs">
+ FIPS home page</A>.</DD>
+<DT><A name="FSF">Free Software Foundation (FSF)</A></DT>
+<DD>An organisation to promote free software, free in the sense of these
+ quotes from their web pages</DD>
+<DD><BLOCKQUOTE> &quot;Free software&quot; is a matter of liberty, not price. To
+ understand the concept, you should think of &quot;free speech&quot;, not &quot;free
+ beer.&quot;
+<P>&quot;Free software&quot; refers to the users' freedom to run, copy,
+ distribute, study, change and improve the software.</P>
+</BLOCKQUOTE>
+<P>See also<A href="#GNU"> GNU</A>,<A href="#GPL"> GNU General Public
+ License</A>, and<A href="http://www.fsf.org"> the FSF site</A>.</P>
+</DD>
+<DT>FreeS/WAN</DT>
+<DD>see<A href="#FreeSWAN"> Linux FreeS/WAN</A></DD>
+<DT><A name="fullnet">Fullnet</A></DT>
+<DD>The CIDR block containing all IPs of its IP version. The<A HREF="#IPv4">
+ IPv4</A> fullnet is written 0.0.0.0/0. Also known as &quot;all&quot; and
+ &quot;default&quot;, fullnet may be used in a routing table to specify a default
+ route, and in a FreeS/WAN<A HREF="#policygroups"> policy group</A> file
+ to specify a default IPsec policy.</DD>
+<DT>FSF</DT>
+<DD>see<A href="#FSF"> Free software Foundation</A></DD>
+<DT><A name="G">G</A></DT>
+<DT><A name="GCHQ">GCHQ</A></DT>
+<DD><A href="http://www.gchq.gov.uk">Government Communications
+ Headquarters</A>, the British organisation for<A href="#SIGINT">
+ signals intelligence</A>.</DD>
+<DT>generator of a prime field</DT>
+<DD>see<A href="#dlog"> discrete logarithm problem</A></DD>
+<DT><A name="GILC">GILC</A></DT>
+<DD><A href="http://www.gilc.org">Global Internet Liberty Campaign</A>,
+ an international organisation advocating, among other things, free
+ availability of cryptography. They have a<A href="http://www.gilc.org/crypto/wassenaar">
+ campaign</A> to remove cryptographic software from the<A href="#Wassenaar.gloss">
+ Wassenaar Arrangement</A>.</DD>
+<DT>Global Internet Liberty Campaign</DT>
+<DD>see<A href="#GILC"> GILC</A>.</DD>
+<DT><A name="GTR">Global Trust Register</A></DT>
+<DD>An attempt to create something like a<A href="#rootCA"> root CA</A>
+ for<A href="#PGP"> PGP</A> by publishing both<A href="#GTR"> as a book</A>
+ and<A href="http://www.cl.cam.ac.uk/Research/Security/Trust-Register">
+ on the web</A> the fingerprints of a set of verified keys for
+ well-known users and organisations.</DD>
+<DT><A name="GMP">GMP</A></DT>
+<DD>The<B> G</B>NU<B> M</B>ulti-<B>P</B>recision library code, used in<A href="#FreeSWAN">
+ Linux FreeS/WAN</A> by<A href="#Pluto"> Pluto</A> for<A href="#public">
+ public key</A> calculations. See the<A href="http://www.swox.com/gmp">
+ GMP home page</A>.</DD>
+<DT><A name="GNU">GNU</A></DT>
+<DD><B>G</B>NU's<B> N</B>ot<B> U</B>nix, the<A href="#FSF"> Free
+ Software Foundation's</A> project aimed at creating a free system with
+ at least the capabilities of Unix.<A href="#Linux"> Linux</A> uses GNU
+ utilities extensively.</DD>
+<DT><A name="#GOST">GOST</A></DT>
+<DD>a Soviet government standard<A href="#block"> block cipher</A>.<A href="#schneier">
+ Applied Cryptography</A> has details.</DD>
+<DT>GPG</DT>
+<DD>see<A href="#GPG"> GNU Privacy Guard</A></DD>
+<DT><A name="GPL">GNU General Public License</A>(GPL, copyleft)</DT>
+<DD>The license developed by the<A href="#FSF"> Free Software Foundation</A>
+ under which<A href="#Linux"> Linux</A>,<A href="#FreeSWAN"> Linux
+ FreeS/WAN</A> and many other pieces of software are distributed. The
+ license allows anyone to redistribute and modify the code, but forbids
+ anyone from distributing executables without providing access to source
+ code. For more details see the file<A href="../COPYING"> COPYING</A>
+ included with GPLed source distributions, including ours, or<A href="http://www.fsf.org/copyleft/gpl.html">
+ the GNU site's GPL page</A>.</DD>
+<DT><A name="GPG">GNU Privacy Guard</A></DT>
+<DD>An open source implementation of Open<A href="#PGP"> PGP</A> as
+ defined in RFC 2440. See their<A href="http://www.gnupg.org"> web site</A>
+</DD>
+<DT>GPL</DT>
+<DD>see<A href="#GPL"> GNU General Public License</A>.</DD>
+<DT><A name="H">H</A></DT>
+<DT><A name="hash">Hash</A></DT>
+<DD>see<A href="#digest"> message digest</A></DD>
+<DT><A name="HMAC">Hashed Message Authentication Code (HMAC)</A></DT>
+<DD>using keyed<A href="#digest"> message digest</A> functions to
+ authenticate a message. This differs from other uses of these
+ functions:
+<UL>
+<LI>In normal usage, the hash function's internal variable are
+ initialised in some standard way. Anyone can reproduce the hash to
+ check that the message has not been altered.</LI>
+<LI>For HMAC usage, you initialise the internal variables from the key.
+ Only someone with the key can reproduce the hash. A successful check of
+ the hash indicates not only that the message is unchanged but also that
+ the creator knew the key.</LI>
+</UL>
+<P>The exact techniques used in<A href="#IPSEC"> IPsec</A> are defined
+ in RFC 2104. They are referred to as HMAC-MD5-96 and HMAC-SHA-96
+ because they output only 96 bits of the hash. This makes some attacks
+ on the hash functions harder.</P>
+</DD>
+<DT>HMAC</DT>
+<DD>see<A href="#HMAC"> Hashed Message Authentication Code</A></DD>
+<DT>HMAC-MD5-96</DT>
+<DD>see<A href="#HMAC"> Hashed Message Authentication Code</A></DD>
+<DT>HMAC-SHA-96</DT>
+<DD>see<A href="#HMAC"> Hashed Message Authentication Code</A></DD>
+<DT><A name="hybrid">Hybrid cryptosystem</A></DT>
+<DD>A system using both<A href="#public"> public key</A> and<A href="#symmetric">
+ symmetric cipher</A> techniques. This works well. Public key methods
+ provide key management and<A href="#signature"> digital signature</A>
+ facilities which are not readily available using symmetric ciphers. The
+ symmetric cipher, however, can do the bulk of the encryption work much
+ more efficiently than public key methods.</DD>
+<DT><A name="I">I</A></DT>
+<DT><A name="IAB">IAB</A></DT>
+<DD><A href="http://www.iab.org/iab">Internet Architecture Board</A>.</DD>
+<DT><A name="ICMP.gloss">ICMP</A></DT>
+<DD><STRONG>I</STRONG>nternet<STRONG> C</STRONG>ontrol<STRONG> M</STRONG>
+essage<STRONG> P</STRONG>rotocol. This is used for various IP-connected
+ devices to manage the network.</DD>
+<DT><A name="IDEA">IDEA</A></DT>
+<DD><B>I</B>nternational<B> D</B>ata<B> E</B>ncrypion<B> A</B>lgorithm,
+ developed in Europe as an alternative to exportable American ciphers
+ such as<A href="#DES"> DES</A> which were<A href="#desnotsecure"> too
+ weak for serious use</A>. IDEA is a<A href="#block"> block cipher</A>
+ using 64-bit blocks and 128-bit keys, and is used in products such as<A href="#PGP">
+ PGP</A>.
+<P>IDEA is not required by the<A href="#IPSEC"> IPsec</A> RFCs and not
+ currently used in<A href="#FreeSWAN"> Linux FreeS/WAN</A>.</P>
+<P>IDEA is patented and, with strictly limited exceptions for personal
+ use, using it requires a license from<A href="http://www.ascom.com">
+ Ascom</A>.</P>
+</DD>
+<DT><A name="IEEE">IEEE</A></DT>
+<DD><A href="http://www.ieee.org">Institute of Electrical and Electronic
+ Engineers</A>, a professional association which, among other things,
+ sets some technical standards</DD>
+<DT><A name="IESG">IESG</A></DT>
+<DD><A href="http://www.iesg.org">Internet Engineering Steering Group</A>
+.</DD>
+<DT><A name="IETF">IETF</A></DT>
+<DD><A href="http://www.ietf.org">Internet Engineering Task Force</A>,
+ the umbrella organisation whose various working groups make most of the
+ technical decisions for the Internet. The IETF<A href="http://www.ietf.org/html.charters/ipsec-charter.html">
+ IPsec working group</A> wrote the<A href="#RFC"> RFCs</A> we are
+ implementing.</DD>
+<DT><A name="IKE">IKE</A></DT>
+<DD><B>I</B>nternet<B> K</B>ey<B> E</B>xchange, based on the<A href="#DH">
+ Diffie-Hellman</A> key exchange protocol. For details, see RFC 2409 and
+ our<A href="ipsec.html"> IPsec</A> document. IKE is implemented in<A href="#FreeSWAN">
+ Linux FreeS/WAN</A> by the<A href="#Pluto"> Pluto daemon</A>.</DD>
+<DT>IKE v2</DT>
+<DD>A proposed replacement for<A href="#IKE"> IKE</A>. There are other
+ candidates, such as<A href="#JFK"> JFK</A>, and at time of writing
+ (March 2002) the choice between them has not yet been made and does not
+ appear imminent.</DD>
+<DT><A name="iOE">iOE</A></DT>
+<DD>See<A HREF="#initiate-only"> Initiate-only opportunistic encryption</A>
+.</DD>
+<DT><A name="IP">IP</A></DT>
+<DD><B>I</B>nternet<B> P</B>rotocol.</DD>
+<DT><A name="masq">IP masquerade</A></DT>
+<DD>A mostly obsolete term for a method of allowing multiple machines to
+ communicate over the Internet when only one IP address is available for
+ their use. The more current term is Network Address Translation or<A href="#NAT.gloss">
+ NAT</A>.</DD>
+<DT><A name="IPng">IPng</A></DT>
+<DD>&quot;IP the Next Generation&quot;, see<A href="#ipv6.gloss"> IPv6</A>.</DD>
+<DT><A name="IPv4">IPv4</A></DT>
+<DD>The current version of the<A href="#IP"> Internet protocol suite</A>
+.</DD>
+<DT><A name="ipv6.gloss">IPv6 (IPng)</A></DT>
+<DD>Version six of the<A href="#IP"> Internet protocol suite</A>,
+ currently being developed. It will replace the current<A href="#IPv4">
+ version four</A>. IPv6 has<A href="#IPSEC"> IPsec</A> as a mandatory
+ component.
+<P>See this<A href="http://playground.sun.com/pub/ipng/html/ipng-main.html">
+ web site</A> for more details, and our<A href="#ipv6"> compatibility</A>
+ document for information on FreeS/WAN and the Linux implementation of
+ IPv6.</P>
+</DD>
+<DT><A name="IPSEC">IPsec</A> or IPSEC</DT>
+<DD><B>I</B>nternet<B> P</B>rotocol<B> SEC</B>urity, security functions
+ (<A href="#authentication">authentication</A> and<A href="#encryption">
+ encryption</A>) implemented at the IP level of the protocol stack. It
+ is optional for<A href="#IPv4"> IPv4</A> and mandatory for<A href="#ipv6.gloss">
+ IPv6</A>.
+<P>This is the standard<A href="#FreeSWAN"> Linux FreeS/WAN</A> is
+ implementing. For more details, see our<A href="ipsec.html"> IPsec
+ Overview</A>. For the standards, see RFCs listed in our<A href="#RFC">
+ RFCs document</A>.</P>
+</DD>
+<DT><A name="IPX">IPX</A></DT>
+<DD>Novell's Netware protocol tunnelled over an IP link. Our<A href="#user.scripts">
+ firewalls</A> document includes an example of using this through an
+ IPsec tunnel.</DD>
+<DT><A name="ISAKMP">ISAKMP</A></DT>
+<DD><B>I</B>nternet<B> S</B>ecurity<B> A</B>ssociation and<B> K</B>ey<B>
+ M</B>anagement<B> P</B>rotocol, defined in RFC 2408.</DD>
+<DT><A name="ITAR">ITAR</A></DT>
+<DD><B>I</B>nternational<B> T</B>raffic in<B> A</B>rms<B> R</B>
+egulations, US regulations administered by the State Department which
+ until recently limited export of, among other things, cryptographic
+ technology and software. ITAR still exists, but the limits on
+ cryptography have now been transferred to the<A href="#EAR"> Export
+ Administration Regulations</A> under the Commerce Department's<A href="#BXA">
+ Bureau of Export Administration</A>.</DD>
+<DT>IV</DT>
+<DD>see<A href="#IV"> Initialisation vector</A></DD>
+<DT><A name="IV">Initialisation Vector (IV)</A></DT>
+<DD>Some cipher<A href="#mode"> modes</A>, including the<A href="#CBC">
+ CBC</A> mode which IPsec uses, require some extra data at the
+ beginning. This data is called the initialisation vector. It need not
+ be secret, but should be different for each message. Its function is to
+ prevent messages which begin with the same text from encrypting to the
+ same ciphertext. That might give an analyst an opening, so it is best
+ prevented.</DD>
+<DT><A name="initiate-only">Initiate-only opportunistic encryption (iOE)</A>
+</DT>
+<DD>A form of<A HREF="#carpediem"> opportunistic encryption</A> (OE) in
+ which a host proposes opportunistic connections, but lacks the reverse
+ DNS records necessary to support incoming opportunistic connection
+ requests. Common among hosts on cable or pppoe connections where the
+ system administrator does not have write access to the DNS reverse map
+ for the host's external IP.
+<P>Configuring for initiate-only opportunistic encryption is described
+ in our<A href="#opp.client"> quickstart</A> document.</P>
+</DD>
+<DT><A name="J">J</A></DT>
+<DT><A name="JFK">JFK</A></DT>
+<DD><STRONG>J</STRONG>ust<STRONG> F</STRONG>ast<STRONG> K</STRONG>eying,
+ a proposed simpler replacement for<A href="#IKE"> IKE.</A></DD>
+<DT><A name="K">K</A></DT>
+<DT><A name="kernel">Kernel</A></DT>
+<DD>The basic part of an operating system (e.g. Linux) which controls
+ the hardware and provides services to all other programs.
+<P>In the Linux release numbering system, an even second digit as in 2.<STRONG>
+2</STRONG>.x indicates a stable or production kernel while an odd number
+ as in 2.<STRONG>3</STRONG>.x indicates an experimental or development
+ kernel. Most users should run a recent kernel version from the
+ production series. The development kernels are primarily for people
+ doing kernel development. Others should consider using development
+ kernels only if they have an urgent need for some feature not yet
+ available in production kernels.</P>
+</DD>
+<DT>Keyed message digest</DT>
+<DD>See<A href="#HMAC"> HMAC</A>.</DD>
+<DT>Key length</DT>
+<DD>see<A href="#brute"> brute force attack</A></DD>
+<DT><A name="KLIPS">KLIPS</A></DT>
+<DD><B>K</B>erne<B>l</B><B> IP</B><B> S</B>ecurity, the<A href="#FreeSWAN">
+ Linux FreeS/WAN</A> project's changes to the<A href="#Linux"> Linux</A>
+ kernel to support the<A href="#IPSEC"> IPsec</A> protocols.</DD>
+<DT><A name="L">L</A></DT>
+<DT><A name="LDAP">LDAP</A></DT>
+<DD><B>L</B>ightweight<B> D</B>irectory<B> A</B>ccess<B> P</B>rotocol,
+ defined in RFCs 1777 and 1778, a method of accessing information stored
+ in directories. LDAP is used by several<A href="#PKI"> PKI</A>
+ implementations, often with X.501 directories and<A href="#X509"> X.509</A>
+ certificates. It may also be used by<A href="#IPSEC"> IPsec</A> to
+ obtain key certifications from those PKIs. This is not yet implemented
+ in<A href="#FreeSWAN"> Linux FreeS/WAN</A>.</DD>
+<DT><A name="LIBDES">LIBDES</A></DT>
+<DD>A publicly available library of<A href="#DES"> DES</A> code, written
+ by Eric Young, which<A href="#FreeSWAN"> Linux FreeS/WAN</A> uses in
+ both<A href="#KLIPS"> KLIPS</A> and<A href="#Pluto"> Pluto</A>.</DD>
+<DT><A name="Linux">Linux</A></DT>
+<DD>A freely available Unix-like operating system based on a kernel
+ originally written for the Intel 386 architecture by (then) student
+ Linus Torvalds. Once his 32-bit kernel was available, the<A href="#GNU">
+ GNU</A> utilities made it a usable system and contributions from many
+ others led to explosive growth.
+<P>Today Linux is a complete Unix replacement available for several CPU
+ architectures -- Intel, DEC/Compaq Alpha, Power PC, both 32-bit SPARC
+ and the 64-bit UltraSPARC, SrongARM, . . . -- with support for multiple
+ CPUs on some architectures.</P>
+<P><A href="#FreeSWAN">Linux FreeS/WAN</A> is intended to run on all
+ CPUs supported by Linux and is known to work on several. See our<A href="#CPUs">
+ compatibility</A> section for a list.</P>
+</DD>
+<DT><A name="FreeSWAN">Linux FreeS/WAN</A></DT>
+<DD>Our implementation of the<A href="#IPSEC"> IPsec</A> protocols,
+ intended to be freely redistributable source code with<A href="#GPL"> a
+ GNU GPL license</A> and no constraints under US or other<A href="#exlaw">
+ export laws</A>. Linux FreeS/WAN is intended to interoperate with other<A
+href="#IPSEC"> IPsec</A> implementations. The name is partly taken, with
+ permission, from the<A href="#SWAN"> S/WAN</A> multi-vendor IPsec
+ compatability effort. Linux FreeS/WAN has two major components,<A href="#KLIPS">
+ KLIPS</A> (KerneL IPsec Support) and the<A href="#Pluto"> Pluto</A>
+ daemon which manages the whole thing.
+<P>See our<A href="ipsec.html"> IPsec section</A> for more detail. For
+ the code see our<A href="http://freeswan.org"> primary site</A> or one
+ of the mirror sites on<A href="#mirrors"> this list</A>.</P>
+</DD>
+<DT><A name="LSM">Linux Security Modules (LSM)</A></DT>
+<DD>a project to create an interface in the Linux kernel that supports
+ plug-in modules for various security policies.
+<P>This allows multiple security projects to take different approaches
+ to security enhancement without tying the kernel down to one particular
+ approach. As I understand the history, several projects were pressing
+ Linus to incorporate their changes, the various sets of changes were
+ incompatible, and his answer was more-or-less &quot;a plague on all your
+ houses; I'll give you an interface, but I won't incorporate anything&quot;.</P>
+<P>It seems to be working. There is a fairly active<A href="http://mail.wirex.com/mailman/listinfo/linux-security-module">
+ LSM mailing list</A>, and several projects are already using the
+ interface.</P>
+</DD>
+<DT>LSM</DT>
+<DD>see<A href="#LSM"> Linux Security Modules</A></DD>
+<DT><A name="M">M</A></DT>
+<DT><A name="list">Mailing list</A></DT>
+<DD>The<A href="#FreeSWAN"> Linux FreeS/WAN</A> project has several
+ public email lists for bug reports and software development
+ discussions. See our document on<A href="mail.html"> mailing lists</A>.</DD>
+<DT><A name="middle">Man-in-the-middle attack</A></DT>
+<DD>An<A href="#active"> active attack</A> in which the attacker
+ impersonates each of the legitimate players in a protocol to the other.
+<P>For example, if<A href="#alicebob"> Alice and Bob</A> are negotiating
+ a key via the<A href="#DH"> Diffie-Hellman</A> key agreement, and are
+ not using<A href="#authentication"> authentication</A> to be certain
+ they are talking to each other, then an attacker able to insert himself
+ in the communication path can deceive both players.</P>
+<P>Call the attacker Mallory. For Bob, he pretends to be Alice. For
+ Alice, he pretends to be Bob. Two keys are then negotiated,
+ Alice-to-Mallory and Bob-to-Mallory. Alice and Bob each think the key
+ they have is Alice-to-Bob.</P>
+<P>A message from Alice to Bob then goes to Mallory who decrypts it,
+ reads it and/or saves a copy, re-encrypts using the Bob-to-Mallory key
+ and sends it along to Bob. Bob decrypts successfully and sends a reply
+ which Mallory decrypts, reads, re-encrypts and forwards to Alice.</P>
+<P>To make this attack effective, Mallory must</P>
+<UL>
+<LI>subvert some part of the network in some way that lets him carry out
+ the deception
+<BR> possible targets: DNS, router, Alice or Bob's machine, mail server,
+ ...</LI>
+<LI>beat any authentication mechanism Alice and Bob use
+<BR> strong authentication defeats the attack entirely; this is why<A href="#IKE">
+ IKE</A> requires authentication</LI>
+<LI>work in real time, delivering messages without introducing a delay
+ large enough to alert the victims
+<BR> not hard if Alice and Bob are using email; quite difficult in some
+ situations.</LI>
+</UL>
+<P>If he manages it, however, it is devastating. He not only gets to
+ read all the messages; he can alter messages, inject his own, forge
+ anything he likes, . . . In fact, he controls the communication
+ completely.</P>
+</DD>
+<DT><A name="mandatory">mandatory access control</A></DT>
+<DD>access control mechanisims which are not settable by the user (see<A href="#discretionary">
+ discretionary access control</A>), but are enforced by the system.
+<P>For example, a document labelled &quot;secret, zebra&quot; might be readable
+ only by someone with secret clearance working on Project Zebra.
+ Ideally, the system will prevent any transfer outside those boundaries.
+ For example, even if you can read it, you should not be able to e-mail
+ it (unless the recipient is appropriately cleared) or print it (unless
+ certain printers are authorised for that classification).</P>
+<P>Mandatory access control is a required feature for some levels of<A href="#rainbow">
+ Rainbow Book</A> or<A href="#cc"> Common Criteria</A> classification,
+ but has not been widely used outside the military and government. There
+ is a good discussion of the issues in Anderson's<A href="#anderson">
+ Security Engineering</A>.</P>
+<P>The<A href="#SElinux"> Security Enhanced Linux</A> project is adding
+ mandatory access control to Linux.</P>
+</DD>
+<DT><A name="manual">Manual keying</A></DT>
+<DD>An IPsec mode in which the keys are provided by the administrator.
+ In FreeS/WAN, they are stored in /etc/ipsec.conf. The alternative,<A href="#auto">
+ automatic keying</A>, is preferred in most cases. See this<A href="#man-auto">
+ discussion</A>.</DD>
+<DT><A name="MD4">MD4</A></DT>
+<DD><A href="#digest">Message Digest Algorithm</A> Four from Ron Rivest
+ of<A href="#RSAco"> RSA</A>. MD4 was widely used a few years ago, but
+ is now considered obsolete. It has been replaced by its descendants<A href="#MD5">
+ MD5</A> and<A href="#SHA"> SHA</A>.</DD>
+<DT><A name="MD5">MD5</A></DT>
+<DD><A href="#digest">Message Digest Algorithm</A> Five from Ron Rivest
+ of<A href="#RSAco"> RSA</A>, an improved variant of his<A href="#MD4">
+ MD4</A>. Like MD4, it produces a 128-bit hash. For details see RFC
+ 1321.
+<P>MD5 is one of two message digest algorithms available in IPsec. The
+ other is<A href="#SHA"> SHA</A>. SHA produces a longer hash and is
+ therefore more resistant to<A href="#birthday"> birthday attacks</A>,
+ but this is not a concern for IPsec. The<A href="#HMAC"> HMAC</A>
+ method used in IPsec is secure even if the underlying hash is not
+ particularly strong against this attack.</P>
+<P>Hans Dobbertin found a weakness in MD5, and people often ask whether
+ this means MD5 is unsafe for IPsec. It doesn't. The IPsec RFCs discuss
+ Dobbertin's attack and conclude that it does not affect MD5 as used for
+ HMAC in IPsec.</P>
+</DD>
+<DT><A name="meet">Meet-in-the-middle attack</A></DT>
+<DD>A divide-and-conquer attack which breaks a cipher into two parts,
+ works against each separately, and compares results. Probably the best
+ known example is an attack on double DES. This applies in principle to
+ any pair of block ciphers, e.g. to an encryption system using, say,
+ CAST-128 and Blowfish, but we will describe it for double DES.
+<P>Double DES encryption and decryption can be written:</P>
+<PRE>        C = E(k2,E(k1,P))
+        P = D(k1,D(k2,C))</PRE>
+<P>Where C is ciphertext, P is plaintext, E is encryption, D is
+ decryption, k1 is one key, and k2 is the other key. If we know a P, C
+ pair, we can try and find the keys with a brute force attack, trying
+ all possible k1, k2 pairs. Since each key is 56 bits, there are 2<SUP>
+112</SUP> such pairs and this attack is painfully inefficient.</P>
+<P>The meet-in-the middle attack re-writes the equations to calculate a
+ middle value M:</P>
+<PRE>        M = E(k1,P)
+        M = D(k2,C)</PRE>
+<P>Now we can try some large number of D(k2,C) decryptions with various
+ values of k2 and store the results in a table. Then start doing E(k1,P)
+ encryptions, checking each result to see if it is in the table.</P>
+<P>With enough table space, this breaks double DES with<NOBR> 2<SUP>56</SUP>
+ + 2<SUP>56</SUP> = 2<SUP>57</SUP>work. Against triple DES, you need<NOBR>
+ 2<SUP>56</SUP> + 2<SUP>112</SUP> ~= 2<SUP>112</SUP>.</P>
+<P>The memory requirements for such attacks can be prohibitive, but
+ there is a whole body of research literature on methods of reducing
+ them.</P>
+</DD>
+<DT><A name="digest">Message Digest Algorithm</A></DT>
+<DD>An algorithm which takes a message as input and produces a hash or
+ digest of it, a fixed-length set of bits which depend on the message
+ contents in some highly complex manner. Design criteria include making
+ it extremely difficult for anyone to counterfeit a digest or to change
+ a message without altering its digest. One essential property is<A href="#collision">
+ collision resistance</A>. The main applications are in message<A href="#authentication">
+ authentication</A> and<A href="#signature"> digital signature</A>
+ schemes. Widely used algorithms include<A href="#MD5"> MD5</A> and<A href="#SHA">
+ SHA</A>. In IPsec, message digests are used for<A href="#HMAC"> HMAC</A>
+ authentication of packets.</DD>
+<DT><A name="MTU">MTU</A></DT>
+<DD><STRONG>M</STRONG>aximum<STRONG> T</STRONG>ransmission<STRONG> U</STRONG>
+nit, the largest size of packet that can be sent over a link. This is
+ determined by the underlying network, but must be taken account of at
+ the IP level.
+<P>IP packets, which can be up to 64K bytes each, must be packaged into
+ lower-level packets of the appropriate size for the underlying
+ network(s) and re-assembled on the other end. When a packet must pass
+ over multiple networks, each with its own MTU, and many of the MTUs are
+ unknown to the sender, this becomes a fairly complex problem. See<A href="#pathMTU">
+ path MTU discovery</A> for details.</P>
+<P>Often the MTU is a few hundred bytes on serial links and 1500 on
+ Ethernet. There are, however, serial link protocols which use a larger
+ MTU to avoid fragmentation at the ethernet/serial boundary, and newer
+ (especially gigabit) Ethernet networks sometimes support much larger
+ packets because these are more efficient in some applications.</P>
+</DD>
+<DT><A name="N">N</A></DT>
+<DT><A name="NAI">NAI</A></DT>
+<DD><A href="http://www.nai.com">Network Associates</A>, a conglomerate
+ formed from<A href="#PGPI"> PGP Inc.</A>, TIS (Trusted Information
+ Systems, a firewall vendor) and McAfee anti-virus products. Among other
+ things, they offer an IPsec-based VPN product.</DD>
+<DT><A name="NAT.gloss">NAT</A></DT>
+<DD><B>N</B>etwork<B> A</B>ddress<B> T</B>ranslation, a process by which
+ firewall machines may change the addresses on packets as they go
+ through. For discussion, see our<A href="#nat.background"> background</A>
+ section.</DD>
+<DT><A name="NIST">NIST</A></DT>
+<DD>The US<A href="http://www.nist.gov"> National Institute of Standards
+ and Technology</A>, responsible for<A href="#FIPS"> FIPS standards</A>
+ including<A href="#DES"> DES</A> and its replacement,<A href="#AES">
+ AES</A>.</DD>
+<DT><A name="nonce">Nonce</A></DT>
+<DD>A<A href="#random"> random</A> value used in an<A href="#authentication">
+ authentication</A> protocol.</DD>
+<DT></DT>
+<DT><A name="non-routable">Non-routable IP address</A></DT>
+<DD>An IP address not normally allowed in the &quot;to&quot; or &quot;from&quot; IP address
+ field header of IP packets.
+<P>Almost invariably, the phrase &quot;non-routable address&quot; means one of the
+ addresses reserved by RFC 1918 for private networks:</P>
+<UL>
+<LI>10.anything</LI>
+<LI>172.x.anything with 16 &lt;= x &lt;= 31</LI>
+<LI>192.168.anything</LI>
+</UL>
+<P>These addresses are commonly used on private networks, e.g. behind a
+ Linux machines doing<A href="#masq"> IP masquerade</A>. Machines within
+ the private network can address each other with these addresses. All
+ packets going outside that network, however, have these addresses
+ replaced before they reach the Internet.</P>
+<P>If any packets using these addresses do leak out, they do not go far.
+ Most routers automatically discard all such packets.</P>
+<P>Various other addresses -- the 127.0.0.0/8 block reserved for local
+ use, 0.0.0.0, various broadcast and network addresses -- cannot be
+ routed over the Internet, but are not normally included in the meaning
+ when the phrase &quot;non-routable address&quot; is used.</P>
+</DD>
+<DT><A name="NSA">NSA</A></DT>
+<DD>The US<A href="http://www.nsa.gov"> National Security Agency</A>,
+ the American organisation for<A href="#SIGINT"> signals intelligence</A>
+, the protection of US government messages and the interception and
+ analysis of other messages. For details, see Bamford's<A href="#puzzle">
+ &quot;The Puzzle Palace&quot;</A>.
+<P>Some<A href="http://www.gwu.edu/~nsarchiv/NSAEBB/NSAEBB23/index.html">
+ history of NSA</A> documents were declassified in response to a FOIA
+ (Freedom of Information Act) request.</P>
+</DD>
+<DT><A name="O">O</A></DT>
+<DT><A name="oakley">Oakley</A></DT>
+<DD>A key determination protocol, defined in RFC 2412.</DD>
+<DT>Oakley groups</DT>
+<DD>The groups used as the basis of<A href="#DH"> Diffie-Hellman</A> key
+ exchange in the Oakley protocol, and in<A href="#IKE"> IKE</A>. Four
+ were defined in the original RFC, and a fifth has been<A href="http://www.lounge.org/ike_doi_errata.html">
+ added since</A>.
+<P>Linux FreeS/WAN currently supports the three groups based on finite
+ fields modulo a prime (Groups 1, 2 and 5) and does not support the
+ elliptic curve groups (3 and 4). For a description of the difference of
+ the types, see<A href="#dlog"> discrete logarithms</A>.</P>
+</DD>
+<DT><A name="OTP">One time pad</A></DT>
+<DD>A cipher in which the key is:
+<UL>
+<LI>as long as the total set of messages to be enciphered</LI>
+<LI>absolutely<A href="#random"> random</A></LI>
+<LI>never re-used</LI>
+</UL>
+<P>Given those three conditions, it can easily be proved that the cipher
+ is perfectly secure, in the sense that an attacker with intercepted
+ message in hand has no better chance of guessing the message than an
+ attacker who has not intercepted the message and only knows the message
+ length. No such proof exists for any other cipher.</P>
+<P>There are, however, several problems with this &quot;perfect&quot; cipher.</P>
+<P>First, it is<STRONG> wildly impractical</STRONG> for most
+ applications. Key management is at best difficult, often completely
+ impossible.</P>
+<P>Second, it is<STRONG> extremely fragile</STRONG>. Small changes which
+ violate the conditions listed above do not just weaken the cipher
+ liitle. Quite often they destroy its security completely.</P>
+<UL>
+<LI>Re-using the pad weakens the cipher to the point where it can be
+ broken with pencil and paper. With a computer, the attack is trivially
+ easy.</LI>
+<LI>Using<EM> anything</EM> less than truly<A href="#random"> random</A>
+ numbers<EM> completely</EM> invalidates the security proof.</LI>
+<LI>In particular, using computer-generated pseudo-random numbers may
+ give an extremely weak cipher. It might also produce a good stream
+ cipher, if the pseudo-random generator is both well-designed and
+ properely seeded.</LI>
+</UL>
+<P>Marketing claims about the &quot;unbreakable&quot; security of various products
+ which somewhat resemble one-time pads are common. Such claims are one
+ of the surest signs of cryptographic<A href="#snake"> snake oil</A>;
+ most systems marketed with such claims are worthless.</P>
+<P>Finally, even if the system is implemented and used correctly, it is<STRONG>
+ highly vulnerable to a substitution attack</STRONG>. If an attacker
+ knows some plaintext and has an intercepted message, he can discover
+ the pad.</P>
+<UL>
+<LI>This does not matter if the attacker is just a<A href="#passive">
+ passive</A> eavesdropper. It gives him no plaintext he didn't already
+ know and we don't care that he learns a pad which we will never re-use.</LI>
+<LI>However, an<A href="#active"> active</A> attacker who knows the
+ plaintext can recover the pad, then use it to encode with whatever he
+ chooses. If he can get his version delivered instead of yours, this may
+ be a disaster. If you send &quot;attack at dawn&quot;, the delivered message can
+ be anything the same length -- perhaps &quot;retreat to east&quot; or &quot;shoot
+ generals&quot;.</LI>
+<LI>An active attacker with only a reasonable guess at the plaintext can
+ try the same attack. If the guess is correct, this works and the
+ attacker's bogus message is delivered. If the guess is wrong, a garbled
+ message is delivered.</LI>
+</UL>
+<P>In general then, despite its theoretical perfection, the one-time-pad
+ has very limited practical application.</P>
+<P>See also the<A href="http://pubweb.nfr.net/~mjr/pubs/otpfaq/"> one
+ time pad FAQ</A>.</P>
+</DD>
+<DT><A name="carpediem">Opportunistic encryption (OE)</A></DT>
+<DD>A situation in which any two IPsec-aware machines can secure their
+ communications, without a pre-shared secret and without a common<A href="#PKI">
+ PKI</A> or previous exchange of public keys. This is one of the goals
+ of the Linux FreeS/WAN project, discussed in our<A href="#goals">
+ introduction</A> section.
+<P>Setting up for opportunistic encryption is described in our<A href="#quickstart">
+ quickstart</A> document.</P>
+</DD>
+<DT><A name="responder">Opportunistic responder</A></DT>
+<DD>A host which accepts, but does not initiate, requests for<A HREF="#carpediem">
+ opportunistic encryption</A> (OE). An opportunistic responder has
+ enabled OE in its<A HREF="#passive.OE"> passive</A> form (pOE) only. A
+ web server or file server may be usefully set up as an opportunistic
+ responder.
+<P>Configuring passive OE is described in our<A href="#policygroups">
+ policy groups</A> document.</P>
+</DD>
+<DT><A name="orange">Orange book</A></DT>
+<DD>the most basic and best known of the US government's<A href="#rainbow">
+ Rainbow Book</A> series of computer security standards.</DD>
+<DT><A name="P">P</A></DT>
+<DT><A name="P1363">P1363 standard</A></DT>
+<DD>An<A href="#IEEE"> IEEE</A> standard for public key cryptography.<A href="http://grouper.ieee.org/groups/1363">
+ Web page</A>.</DD>
+<DT><A name="pOE">pOE</A></DT>
+<DD>See<A href="#passive.OE"> Passive opportunistic encryption</A>.</DD>
+<DT><A name="passive">Passive attack</A></DT>
+<DD>An attack in which the attacker only eavesdrops and attempts to
+ analyse intercepted messages, as opposed to an<A href="#active"> active
+ attack</A> in which he diverts messages or generates his own.</DD>
+<DT><A name="passive.OE">Passive opportunistic encryption (pOE)</A></DT>
+<DD>A form of<A HREF="#carpediem"> opportunistic encryption</A> (OE) in
+ which the host will accept opportunistic connection requests, but will
+ not initiate such requests. A host which runs OE in its passive form
+ only is known as an<A HREF="#responder"> opportunistic responder</A>.
+<P>Configuring passive OE is described in our<A href="#policygroups">
+ policy groups</A> document.</P>
+</DD>
+<DT><A name="pathMTU">Path MTU discovery</A></DT>
+<DD>The process of discovering the largest packet size which all links
+ on a path can handle without fragmentation -- that is, without any
+ router having to break the packet up into smaller pieces to match the<A href="#MTU">
+ MTU</A> of its outgoing link.
+<P>This is done as follows:</P>
+<UL>
+<LI>originator sends the largest packets allowed by<A href="#MTU"> MTU</A>
+ of the first link, setting the DF (<STRONG>d</STRONG>on't<STRONG> f</STRONG>
+ragment) bit in the packet header</LI>
+<LI>any router which cannot send the packet on (outgoing MTU is too
+ small for it, and DF prevents fragmenting it to match) sends back an<A href="#ICMP.gloss">
+ ICMP</A> packet reporting the problem</LI>
+<LI>originator looks at ICMP message and tries a smaller size</LI>
+<LI>eventually, you settle on a size that can pass all routers</LI>
+<LI>thereafter, originator just sends that size and no-one has to
+ fragment</LI>
+</UL>
+<P>Since this requires co-operation of many systems, and since the next
+ packet may travel a different path, this is one of the trickier areas
+ of IP programming. Bugs that have shown up over the years have
+ included:</P>
+<UL>
+<LI>malformed ICMP messages</LI>
+<LI>hosts that ignore or mishandle these ICMP messages</LI>
+<LI>firewalls blocking the ICMP messages so host does not see them</LI>
+</UL>
+<P>Since IPsec adds a header, it increases packet size and may require
+ fragmentation even where incoming and outgoing MTU are equal.</P>
+</DD>
+<DT><A name="PFS">Perfect forward secrecy (PFS)</A></DT>
+<DD>A property of systems such as<A href="#DH"> Diffie-Hellman</A> key
+ exchange which use a long-term key (such as the shared secret in IKE)
+ and generate short-term keys as required. If an attacker who acquires
+ the long-term key<EM> provably</EM> can
+<UL>
+<LI><EM>neither</EM> read previous messages which he may have archived</LI>
+<LI><EM>nor</EM> read future messages without performing additional
+ successful attacks</LI>
+</UL>
+<P>then the system has PFS. The attacker needs the short-term keys in
+ order to read the trafiic and merely having the long-term key does not
+ allow him to infer those. Of course, it may allow him to conduct
+ another attack (such as<A href="#middle"> man-in-the-middle</A>) which
+ gives him some short-term keys, but he does not automatically get them
+ just by acquiring the long-term key.</P>
+<P>See also<A href="http://sandelman.ottawa.on.ca/ipsec/1996/08/msg00123.html">
+ Phil Karn's definition</A>.</P>
+</DD>
+<DT>PFS</DT>
+<DD>see Perfect Forward Secrecy</DD>
+<DT><A name="PGP">PGP</A></DT>
+<DD><B>P</B>retty<B> G</B>ood<B> P</B>rivacy, a personal encryption
+ system for email based on public key technology, written by Phil
+ Zimmerman.
+<P>The 2.xx versions of PGP used the<A href="#RSA"> RSA</A> public key
+ algorithm and used<A href="#IDEA"> IDEA</A> as the symmetric cipher.
+ These versions are described in RFC 1991 and in<A href="#PGP">
+ Garfinkel's book</A>. Since version 5, the products from<A href="#PGPI">
+ PGP Inc</A>. have used<A href="#DH"> Diffie-Hellman</A> public key
+ methods and<A href="#CAST128"> CAST-128</A> symmetric encryption. These
+ can verify signatures from the 2.xx versions, but cannot exchange
+ encryted messages with them.</P>
+<P>An<A href="#IETF"> IETF</A> working group has issued RFC 2440 for an
+ &quot;Open PGP&quot; standard, similar to the 5.x versions. PGP Inc. staff were
+ among the authors. A free<A href="#GPG"> Gnu Privacy Guard</A> based on
+ that standard is now available.</P>
+<P>For more information on PGP, including how to obtain it, see our
+ cryptography<A href="#tools"> links</A>.</P>
+</DD>
+<DT><A name="PGPI">PGP Inc.</A></DT>
+<DD>A company founded by Zimmerman, the author of<A href="#PGP"> PGP</A>
+, now a division of<A href="#NAI"> NAI</A>. See the<A href="http://www.pgp.com">
+ corporate website</A>. Zimmerman left in 2001, and early in 2002 NAI
+ announced that they would no longer sell PGP..
+<P>Versions 6.5 and later of the PGP product include PGPnet, an IPsec
+ client for Macintosh or for Windows 95/98/NT. See our<A href="interop.html#pgpnet">
+ interoperation documen</A>t.</P>
+</DD>
+<DT><A name="photuris">Photuris</A></DT>
+<DD>Another key negotiation protocol, an alternative to<A href="#IKE">
+ IKE</A>, described in RFCs 2522 and 2523.</DD>
+<DT><A name="PPP">PPP</A></DT>
+<DD><B>P</B>oint-to-<B>P</B>oint<B> P</B>rotocol, originally a method of
+ connecting over modems or serial lines, but see also PPPoE.</DD>
+<DT><A name="PPPoE">PPPoE</A></DT>
+<DD><B>PPP</B><B> o</B>ver<B> E</B>thernet, a somewhat odd protocol that
+ makes Ethernet look like a point-to-point serial link. It is widely
+ used for cable or ADSL Internet services, apparently mainly because it
+ lets the providers use access control and address assignmment
+ mechanisms developed for dialup networks.<A href="http://www.roaringpenguin.com">
+ Roaring Penguin</A> provide a widely used Linux implementation.</DD>
+<DT><A name="PPTP">PPTP</A></DT>
+<DD><B>P</B>oint-to-<B>P</B>oint<B> T</B>unneling<B> P</B>rotocol, used
+ in some Microsoft VPN implementations. Papers discussing weaknesses in
+ it are on<A href="http://www.counterpane.com/publish.html">
+ counterpane.com</A>. It is now largely obsolete, replaced by L2TP.</DD>
+<DT><A name="PKI">PKI</A></DT>
+<DD><B>P</B>ublic<B> K</B>ey<B> I</B>nfrastructure, the things an
+ organisation or community needs to set up in order to make<A href="#public">
+ public key</A> cryptographic technology a standard part of their
+ operating procedures.
+<P>There are several PKI products on the market. Typically they use a
+ hierarchy of<A href="#CA"> Certification Authorities (CAs)</A>. Often
+ they use<A href="#LDAP"> LDAP</A> access to<A href="#X509"> X.509</A>
+ directories to implement this.</P>
+<P>See<A href="#web"> Web of Trust</A> for a different sort of
+ infrastructure.</P>
+</DD>
+<DT><A name="PKIX">PKIX</A></DT>
+<DD><B>PKI</B> e<B>X</B>change, an<A href="#IETF"> IETF</A> standard
+ that allows<A href="#PKI"> PKI</A>s to talk to each other.
+<P>This is required, for example, when users of a corporate PKI need to
+ communicate with people at client, supplier or government
+ organisations, any of which may have a different PKI in place. I should
+ be able to talk to you securely whenever:</P>
+<UL>
+<LI>your organisation and mine each have a PKI in place</LI>
+<LI>you and I are each set up to use those PKIs</LI>
+<LI>the two PKIs speak PKIX</LI>
+<LI>the configuration allows the conversation</LI>
+</UL>
+<P>At time of writing (March 1999), this is not yet widely implemented
+ but is under quite active development by several groups.</P>
+</DD>
+<DT><A name="plaintext">Plaintext</A></DT>
+<DD>The unencrypted input to a cipher, as opposed to the encrypted<A href="#ciphertext">
+ ciphertext</A> output.</DD>
+<DT><A name="Pluto">Pluto</A></DT>
+<DD>The<A href="#FreeSWAN"> Linux FreeS/WAN</A> daemon which handles key
+ exchange via the<A href="#IKE"> IKE</A> protocol, connection
+ negotiation, and other higher-level tasks. Pluto calls the<A href="#KLIPS">
+ KLIPS</A> kernel code as required. For details, see the manual page
+ ipsec_pluto(8).</DD>
+<DT><A name="public">Public Key Cryptography</A></DT>
+<DD>In public key cryptography, keys are created in matched pairs.
+ Encrypt with one half of a pair and only the matching other half can
+ decrypt it. This contrasts with<A href="#symmetric"> symmetric or
+ secret key cryptography</A> in which a single key known to both parties
+ is used for both encryption and decryption.
+<P>One half of each pair, called the public key, is made public. The
+ other half, called the private key, is kept secret. Messages can then
+ be sent by anyone who knows the public key to the holder of the private
+ key. Encrypt with the public key and you know that only someone with
+ the matching private key can decrypt.</P>
+<P>Public key techniques can be used to create<A href="#signature">
+ digital signatures</A> and to deal with key management issues, perhaps
+ the hardest part of effective deployment of<A href="#symmetric">
+ symmetric ciphers</A>. The resulting<A href="#hybrid"> hybrid
+ cryptosystems</A> use public key methods to manage keys for symmetric
+ ciphers.</P>
+<P>Many organisations are currently creating<A href="#PKI"> PKIs, public
+ key infrastructures</A> to make these benefits widely available.</P>
+</DD>
+<DT>Public Key Infrastructure</DT>
+<DD>see<A href="#PKI"> PKI</A></DD>
+<DT><A name="Q">Q</A></DT>
+<DT><A name="R">R</A></DT>
+<DT><A name="rainbow">Rainbow books</A></DT>
+<DD>A set of US government standards for evaluation of &quot;trusted computer
+ systems&quot;, of which the best known was the<A href="#orange"> Orange Book</A>
+. One fairly often hears references to &quot;C2 security&quot; or a product
+ &quot;evaluated at B1&quot;. The Rainbow books define the standards referred to
+ in those comments.
+<P>See this<A href="http://www.fas.org/irp/nsa/rainbow.htm"> reference
+ page</A>.</P>
+<P>The Rainbow books are now mainly obsolete, replaced by the
+ international<A href="#cc"> Common Criteria</A> standards.</P>
+</DD>
+<DT><A name="random">Random</A></DT>
+<DD>A remarkably tricky term, far too much so for me to attempt a
+ definition here. Quite a few cryptosystems have been broken via attacks
+ on weak random number generators, even when the rest of the system was
+ sound.
+<P>See<A href="http://nis.nsf.net/internet/documents/rfc/rfc1750.txt">
+ RFC 1750</A> for the theory.</P>
+<P>See the manual pages for<A href="manpage.d/ipsec_ranbits.8.html">
+ ipsec_ranbits(8)</A> and ipsec_prng(3) for more on FreeS/WAN's use of
+ randomness. Both depend on the random(4) device driver..</P>
+<P>A couple of years ago, there was extensive mailing list discussion
+ (archived<A href="http://www.openpgp.net/random/index.html"> here</A>
+)of Linux /dev/random and FreeS/WAN. Since then, the design of the
+ random(4) driver has changed considerably. Linux 2.4 kernels have the
+ new driver..</P>
+</DD>
+<DT>Raptor</DT>
+<DD>A firewall product for Windows NT offerring IPsec-based VPN
+ services. Linux FreeS/WAN interoperates with Raptor; see our<A href="#raptor">
+ interop</A> document for details. Raptor have recently merged with
+ Axent.</DD>
+<DT><A name="RC4">RC4</A></DT>
+<DD><B>R</B>ivest<B> C</B>ipher four, designed by Ron Rivest of<A href="#RSAco">
+ RSA</A> and widely used. Believed highly secure with adequate key
+ length, but often implemented with inadequate key length to comply with
+ export restrictions.</DD>
+<DT><A name="RC6">RC6</A></DT>
+<DD><B>R</B>ivest<B> C</B>ipher six,<A href="#RSAco"> RSA</A>'s<A href="#AES">
+ AES</A> candidate cipher.</DD>
+<DT><A name="replay">Replay attack</A></DT>
+<DD>An attack in which the attacker records data and later replays it in
+ an attempt to deceive the recipient.</DD>
+<DT><A name="reverse">Reverse map</A></DT>
+<DD>In<A href="#DNS"> DNS</A>, a table where IP addresses can be used as
+ the key for lookups which return a system name and/or other
+ information.</DD>
+<DT>RFC</DT>
+<DD><B>R</B>equest<B> F</B>or<B> C</B>omments, an Internet document.
+ Some RFCs are just informative. Others are standards.
+<P>Our list of<A href="#IPSEC"> IPsec</A> and other security-related
+ RFCs is<A href="#RFC"> here</A>, along with information on methods of
+ obtaining them.</P>
+</DD>
+<DT><A name="rijndael">Rijndael</A></DT>
+<DD>a<A href="#block"> block cipher</A> designed by two Belgian
+ cryptographers, winner of the US government's<A href="#AES"> AES</A>
+ contest to pick a replacement for<A href="#DES"> DES</A>. See the<A href="http://www.esat.kuleuven.ac.be/~rijmen/rijndael">
+ Rijndael home page</A>.</DD>
+<DT><A name="RIPEMD">RIPEMD</A></DT>
+<DD>A<A href="#digest"> message digest</A> algorithm. The current
+ version is RIPEMD-160 which gives a 160-bit hash.</DD>
+<DT><A name="rootCA">Root CA</A></DT>
+<DD>The top level<A href="#CA"> Certification Authority</A> in a
+ hierachy of such authorities.</DD>
+<DT><A name="routable">Routable IP address</A></DT>
+<DD>Most IP addresses can be used as &quot;to&quot; and &quot;from&quot; addresses in packet
+ headers. These are the routable addresses; we expect routing to be
+ possible for them. If we send a packet to one of them, we expect (in
+ most cases; there are various complications) that it will be delivered
+ if the address is in use and will cause an<A href="#ICMP.gloss"> ICMP</A>
+ error packet to come back to us if not.
+<P>There are also several classes of<A href="#non-routable">
+ non-routable</A> IP addresses.</P>
+</DD>
+<DT><A name="RSA">RSA algorithm</A></DT>
+<DD><B>R</B>ivest<B> S</B>hamir<B> A</B>dleman<A href="#public"> public
+ key</A> algorithm, named for its three inventors. It is widely used and
+ likely to become moreso since it became free of patent encumbrances in
+ September 2000.
+<P>RSA can be used to provide either<A href="#encryption"> encryption</A>
+ or<A href="#signature"> digital signatures</A>. In IPsec, it is used
+ only for signatures. These provide gateway-to-gateway<A href="#authentication">
+ authentication</A> for<A href="#IKE"> IKE</A> negotiations.</P>
+<P>For a full explanation of the algorithm, consult one of the standard
+ references such as<A href="#schneier"> Applied Cryptography</A>. A
+ simple explanation is:</P>
+<P>The great 17th century French mathematician<A href="http://www-groups.dcs.st-andrews.ac.uk/~history/Mathematicians/Fermat.html">
+ Fermat</A> proved that,</P>
+<P>for any prime p and number x, 0 &lt;= x &lt; p:</P>
+<PRE>        x^p == x         modulo p
+        x^(p-1) == 1     modulo p, non-zero x
+      </PRE>
+<P>From this it follows that if we have a pair of primes p, q and two
+ numbers e, d such that:</P>
+<PRE>        ed == 1          modulo lcm( p-1, q-1)
+      </PRE>
+ where lcm() is least common multiple, then
+<BR> for all x, 0 &lt;= x &lt; pq:
+<PRE>      x^ed == x           modulo pq
+      </PRE>
+<P>So we construct such as set of numbers p, q, e, d and publish the
+ product N=pq and e as the public key. Using c for<A href="#ciphertext">
+ ciphertext</A> and i for the input<A href="#plaintext"> plaintext</A>,
+ encryption is then:</P>
+<PRE>        c = i^e           modulo N
+      </PRE>
+<P>An attacker cannot deduce i from the cyphertext c, short of either
+ factoring N or solving the<A href="#dlog"> discrete logarithm</A>
+ problem for this field. If p, q are large primes (hundreds or thousands
+ of bits) no efficient solution to either problem is known.</P>
+<P>The receiver, knowing the private key (N and d), can readily recover
+ the plaintext p since:</P>
+<PRE>        c^d == (i^e)^d    modulo N
+            == i^ed       modulo N
+            == i          modulo N
+      </PRE>
+<P>This gives an effective public key technique, with only a couple of
+ problems. It uses a good deal of computer time, since calculations with
+ large integers are not cheap, and there is no proof it is necessarily
+ secure since no-one has proven either factoring or discrete log cannot
+ be done efficiently. Quite a few good mathematicians have tried both
+ problems, and no-one has announced success, but there is no proof they
+ are insoluble.</P>
+</DD>
+<DT><A name="RSAco">RSA Data Security</A></DT>
+<DD>A company founded by the inventors of the<A href="#RSA"> RSA</A>
+ public key algorithm.</DD>
+<DT><A name="S">S</A></DT>
+<DT><A name="SA">SA</A></DT>
+<DD><B>S</B>ecurity<B> A</B>ssociation, the channel negotiated by the
+ higher levels of an<A href="#IPSEC"> IPsec</A> implementation (<A href="#IKE">
+IKE</A>) and used by the lower (<A href="#ESP">ESP</A> and<A href="#AH">
+ AH</A>). SAs are unidirectional; you need a pair of them for two-way
+ communication.
+<P>An SA is defined by three things -- the destination, the protocol (<A href="#AH">
+AH</A> or<A href="#ESP">ESP</A>) and the<A href="SPI"> SPI</A>, security
+ parameters index. It is used as an index to look up other things such
+ as session keys and intialisation vectors.</P>
+<P>For more detail, see our section on<A href="ipsec.html"> IPsec</A>
+ and/or RFC 2401.</P>
+</DD>
+<DT><A name="SElinux">SE Linux</A></DT>
+<DD><STRONG>S</STRONG>ecurity<STRONG> E</STRONG>nhanced Linux, an<A href="#NSA">
+ NSA</A>-funded project to add<A href="#mandatory"> mandatory access
+ control</A> to Linux. See the<A href="http://www.nsa.gov/selinux">
+ project home page</A>.
+<P>According to their web pages, this work will include extending
+ mandatory access controls to IPsec tunnels.</P>
+<P>Recent versions of SE Linux code use the<A href="#LSM"> Linux
+ Security Module</A> interface.</P>
+</DD>
+<DT><A name="SDNS">Secure DNS</A></DT>
+<DD>A version of the<A href="#DNS"> DNS or Domain Name Service</A>
+ enhanced with authentication services. This is being designed by the<A href="#IETF">
+ IETF</A> DNS security<A href="http://www.ietf.org/ids.by.wg/dnssec.html">
+ working group</A>. Check the<A href="http://www.isc.org/bind.html">
+ Internet Software Consortium</A> for information on implementation
+ progress and for the latest version of<A href="#BIND"> BIND</A>.
+ Another site has<A href="http://www.toad.com/~dnssec"> more information</A>
+.
+<P><A href="#IPSEC">IPsec</A> can use this plus<A href="#DH">
+ Diffie-Hellman key exchange</A> to bootstrap itself. This allows<A href="#carpediem">
+ opportunistic encryption</A>. Any pair of machines which can
+ authenticate each other via DNS can communicate securely, without
+ either a pre-existing shared secret or a shared<A href="#PKI"> PKI</A>.</P>
+</DD>
+<DT>Secret key cryptography</DT>
+<DD>See<A href="#symmetric"> symmetric cryptography</A></DD>
+<DT>Security Association</DT>
+<DD>see<A href="#SA"> SA</A></DD>
+<DT>Security Enhanced Linux</DT>
+<DD>see<A href="#SElinux"> SE Linux</A></DD>
+<DT><A name="sequence">Sequence number</A></DT>
+<DD>A number added to a packet or message which indicates its position
+ in a sequence of packets or messages. This provides some security
+ against<A href="#replay"> replay attacks</A>.
+<P>For<A href="#auto"> automatic keying</A> mode, the<A href="#IPSEC">
+ IPsec</A> RFCs require that the sender generate sequence numbers for
+ each packet, but leave it optional whether the receiver does anything
+ with them.</P>
+</DD>
+<DT><A name="SHA">SHA</A></DT>
+<DT>SHA-1</DT>
+<DD><B>S</B>ecure<B> H</B>ash<B> A</B>lgorithm, a<A href="#digest">
+ message digest algorithm</A> developed by the<A href="#NSA"> NSA</A>
+ for use in the Digital Signature standard,<A href="#FIPS"> FIPS</A>
+ number 186 from<A href="#NIST"> NIST</A>. SHA is an improved variant of<A
+href="#MD4"> MD4</A> producing a 160-bit hash.
+<P>SHA is one of two message digest algorithms available in IPsec. The
+ other is<A href="#MD5"> MD5</A>. Some people do not trust SHA because
+ it was developed by the<A href="#NSA"> NSA</A>. There is, as far as we
+ know, no cryptographic evidence that SHA is untrustworthy, but this
+ does not prevent that view from being strongly held.</P>
+<P>The NSA made one small change after the release of the original SHA.
+ They did not give reasons. Iit may be a defense against some attack
+ they found and do not wish to disclose. Technically the modified
+ algorithm should be called SHA-1, but since it has replaced the
+ original algorithm in nearly all applications, it is generally just
+ referred to as SHA..</P>
+</DD>
+<DT><A name="SHA-256">SHA-256</A></DT>
+<DT>SHA-384</DT>
+<DT>SHA-512</DT>
+<DD>Newer variants of SHA designed to match the strength of the 128, 192
+ and 256-bit keys of<A href="#AES"> AES</A>. The work to break an
+ encryption algorithm's strength by<A href="#brute"> brute force</A> is
+ 2
+<!--math xmlns="http://www.w3.org/1998/Math/MathML"-->
+
+<!--msup-->
+
+<!--mi-->
+ keylength</(null)></(null)></(null)> operations but a<A href="birthday">
+ birthday attack</A> on a hash needs only 2
+<!--math xmlns="http://www.w3.org/1998/Math/MathML"-->
+
+<!--msup-->
+
+<!--mrow-->
+
+<!--mi-->
+ hashlength</(null)>
+<!--mo-->
+ /</(null)>
+<!--mn-->
+
+ 2</(null)></(null)></(null)></(null)> , so as a general rule you need a
+ hash twice the size of the key to get similar strength. SHA-256,
+ SHA-384 and SHA-512 are designed to match the 128, 192 and 256-bit key
+ sizes of AES, respectively.</DD>
+<DT><A name="SIGINT">Signals intelligence (SIGINT)</A></DT>
+<DD>Activities of government agencies from various nations aimed at
+ protecting their own communications and reading those of others.
+ Cryptography, cryptanalysis, wiretapping, interception and monitoring
+ of various sorts of signals. The players include the American<A href="#NSA">
+ NSA</A>, British<A href="#GCHQ"> GCHQ</A> and Canadian<A href="#CSE">
+ CSE</A>.</DD>
+<DT><A name="SKIP">SKIP</A></DT>
+<DD><B>S</B>imple<B> K</B>ey management for<B> I</B>nternet<B> P</B>
+rotocols, an alternative to<A href="#IKE"> IKE</A> developed by Sun and
+ being marketed by their<A href="http://skip.incog.com"> Internet
+ Commerce Group</A>.</DD>
+<DT><A name="snake">Snake oil</A></DT>
+<DD>Bogus cryptography. See the<A href="http://www.interhack.net/people/cmcurtin/snake-oil-faq.html">
+ Snake Oil FAQ</A> or<A href="http://www.counterpane.com/crypto-gram-9902.html#snakeoil">
+ this paper</A> by Schneier.</DD>
+<DT><A name="SPI">SPI</A></DT>
+<DD><B>S</B>ecurity<B> P</B>arameter<B> I</B>ndex, an index used within<A
+href="#IPSEC"> IPsec</A> to keep connections distinct. A<A href="#SA">
+ Security Association (SA)</A> is defined by destination, protocol and
+ SPI. Without the SPI, two connections to the same gateway using the
+ same protocol could not be distinguished.
+<P>For more detail, see our<A href="ipsec.html"> IPsec</A> section
+ and/or RFC 2401.</P>
+</DD>
+<DT><A name="SSH">SSH</A></DT>
+<DD><B>S</B>ecure<B> SH</B>ell, an encrypting replacement for the
+ insecure Berkeley commands whose names begin with &quot;r&quot; for &quot;remote&quot;:
+ rsh, rlogin, etc.
+<P>For more information on SSH, including how to obtain it, see our
+ cryptography<A href="#tools"> links</A>.</P>
+</DD>
+<DT><A name="SSHco">SSH Communications Security</A></DT>
+<DD>A company founded by the authors of<A href="#SSH"> SSH</A>. Offices
+ are in<A href="http://www.ssh.fi"> Finland</A> and<A href="http://www.ipsec.com">
+ California</A>. They have a toolkit for developers of IPsec
+ applications.</DD>
+<DT><A name="SSL">SSL</A></DT>
+<DD><A href="http://home.netscape.com/eng/ssl3">Secure Sockets Layer</A>
+, a set of encryption and authentication services for web browsers,
+ developed by Netscape. Widely used in Internet commerce. Also known as<A
+href="#TLS"> TLS</A>.</DD>
+<DT>SSLeay</DT>
+<DD>A free implementation of<A href="#SSL"> SSL</A> by Eric Young (eay)
+ and others. Developed in Australia; not subject to US export controls.</DD>
+<DT><A name="static">static IP address</A></DT>
+<DD>an IP adddress which is pre-set on the machine itself, as opposed to
+ a<A href="#dynamic"> dynamic address</A> which is assigned by a<A href="#DHCP">
+ DHCP</A> server or obtained as part of the process of establishing a<A href="#PPP">
+ PPP</A> or<A href="#PPPoE"> PPPoE</A> connection</DD>
+<DT><A name="stream">Stream cipher</A></DT>
+<DD>A<A href="#symmetric"> symmetric cipher</A> which produces a stream
+ of output which can be combined (often using XOR or bytewise addition)
+ with the plaintext to produce ciphertext. Contrasts with<A href="#block">
+ block cipher</A>.
+<P><A href="#IPSEC">IPsec</A> does not use stream ciphers. Their main
+ application is link-level encryption, for example of voice, video or
+ data streams on a wire or a radio signal.</P>
+</DD>
+<DT><A name="subnet">subnet</A></DT>
+<DD>A group of IP addresses which are logically one network, typically
+ (but not always) assigned to a group of physically connected machines.
+ The range of addresses in a subnet is described using a subnet mask.
+ See next entry.</DD>
+<DT>subnet mask</DT>
+<DD>A method of indicating the addresses included in a subnet. Here are
+ two equivalent examples:
+<UL>
+<LI>101.101.101.0/24</LI>
+<LI>101.101.101.0 with mask 255.255.255.0</LI>
+</UL>
+<P>The '24' is shorthand for a mask with the top 24 bits one and the
+ rest zero. This is exactly the same as 255.255.255.0 which has three
+ all-ones bytes and one all-zeros byte.</P>
+<P>These indicate that, for this range of addresses, the top 24 bits are
+ to be treated as naming a network (often referred to as &quot;the
+ 101.101.101.0/24 subnet&quot;) while most combinations of the low 8 bits can
+ be used to designate machines on that network. Two addresses are
+ reserved; 101.101.101.0 refers to the subnet rather than a specific
+ machine while 101.101.101.255 is a broadcast address. 1 to 254 are
+ available for machines.</P>
+<P>It is common to find subnets arranged in a hierarchy. For example, a
+ large company might have a /16 subnet and allocate /24 subnets within
+ that to departments. An ISP might have a large subnet and allocate /26
+ subnets (64 addresses, 62 usable) to business customers and /29 subnets
+ (8 addresses, 6 usable) to residential clients.</P>
+</DD>
+<DT><A name="SWAN">S/WAN</A></DT>
+<DD>Secure Wide Area Network, a project involving<A href="#RSAco"> RSA
+ Data Security</A> and a number of other companies. The goal was to
+ ensure that all their<A href="#IPSEC"> IPsec</A> implementations would
+ interoperate so that their customers can communicate with each other
+ securely.</DD>
+<DT><A name="symmetric">Symmetric cryptography</A></DT>
+<DD>Symmetric cryptography, also referred to as conventional or secret
+ key cryptography, relies on a<EM> shared secret key</EM>, identical for
+ sender and receiver. Sender encrypts with that key, receiver decrypts
+ with it. The idea is that an eavesdropper without the key be unable to
+ read the messages. There are two main types of symmetric cipher,<A href="#block">
+ block ciphers</A> and<A href="#stream"> stream ciphers</A>.
+<P>Symmetric cryptography contrasts with<A href="#public"> public key</A>
+ or asymmetric systems where the two players use different keys.</P>
+<P>The great difficulty in symmetric cryptography is, of course, key
+ management. Sender and receiver<EM> must</EM> have identical keys and
+ those keys<EM> must</EM> be kept secret from everyone else. Not too
+ much of a problem if only two people are involved and they can
+ conveniently meet privately or employ a trusted courier. Quite a
+ problem, though, in other circumstances.</P>
+<P>It gets much worse if there are many people. An application might be
+ written to use only one key for communication among 100 people, for
+ example, but there would be serious problems. Do you actually trust all
+ of them that much? Do they trust each other that much? Should they?
+ What is at risk if that key is compromised? How are you going to
+ distribute that key to everyone without risking its secrecy? What do
+ you do when one of them leaves the company? Will you even know?</P>
+<P>On the other hand, if you need unique keys for every possible
+ connection between a group of 100, then each user must have 99 keys.
+ You need either 99*100/2 = 4950<EM> secure</EM> key exchanges between
+ users or a central authority that<EM> securely</EM> distributes 100 key
+ packets, each with a different set of 99 keys.</P>
+<P>Either of these is possible, though tricky, for 100 users. Either
+ becomes an administrative nightmare for larger numbers. Moreover, keys<EM>
+ must</EM> be changed regularly, so the problem of key distribution
+ comes up again and again. If you use the same key for many messages
+ then an attacker has more text to work with in an attempt to crack that
+ key. Moreover, one successful crack will give him or her the text of
+ all those messages.</P>
+<P>In short, the<EM> hardest part of conventional cryptography is key
+ management</EM>. Today the standard solution is to build a<A href="#hybrid">
+ hybrid system</A> using<A href="#public"> public key</A> techniques to
+ manage keys.</P>
+</DD>
+<DT><A name="T">T</A></DT>
+<DT><A name="TIS">TIS</A></DT>
+<DD>Trusted Information Systems, a firewall vendor now part of<A href="#NAI">
+ NAI</A>. Their Gauntlet product offers IPsec VPN services. TIS
+ implemented the first version of<A href="#SDNS"> Secure DNS</A> on a<A href="#DARPA">
+ DARPA</A> contract.</DD>
+<DT><A name="TLS">TLS</A></DT>
+<DD><B>T</B>ransport<B> L</B>ayer<B> S</B>ecurity, a newer name for<A href="#SSL">
+ SSL</A>.</DD>
+<DT><A name="TOS">TOS field</A></DT>
+<DD>The<STRONG> T</STRONG>ype<STRONG> O</STRONG>f<STRONG> S</STRONG>
+ervice field in an IP header, used to control qualkity of service
+ routing.</DD>
+<DT><A name="traffic">Traffic analysis</A></DT>
+<DD>Deducing useful intelligence from patterns of message traffic,
+ without breaking codes or reading the messages. In one case during
+ World War II, the British guessed an attack was coming because all
+ German radio traffic stopped. The &quot;radio silence&quot; order, intended to
+ preserve security, actually gave the game away.
+<P>In an industrial espionage situation, one might deduce something
+ interesting just by knowing that company A and company B were talking,
+ especially if one were able to tell which departments were involved, or
+ if one already knew that A was looking for acquisitions and B was
+ seeking funds for expansion.</P>
+<P>In general, traffic analysis by itself is not very useful. However,
+ in the context of a larger intelligence effort where quite a bit is
+ already known, it can be very useful. When you are solving a complex
+ puzzle, every little bit helps.</P>
+<P><A href="#IPSEC">IPsec</A> itself does not defend against traffic
+ analysis, but carefully thought out systems using IPsec can provide at
+ least partial protection. In particular, one might want to encrypt more
+ traffic than was strictly necessary, route things in odd ways, or even
+ encrypt dummy packets, to confuse the analyst. We discuss this<A href="#traffic.resist">
+ here</A>.</P>
+</DD>
+<DT><A name="transport">Transport mode</A></DT>
+<DD>An IPsec application in which the IPsec gateway is the destination
+ of the protected packets, a machine acts as its own gateway. Contrast
+ with<A href="#tunnel"> tunnel mode</A>.</DD>
+<DT>Triple DES</DT>
+<DD>see<A href="#3DES"> 3DES</A></DD>
+<DT><A name="TTL">TTL</A></DT>
+<DD><STRONG>T</STRONG>ime<STRONG> T</STRONG>o<STRONG> L</STRONG>ive,
+ used to control<A href="#DNS"> DNS</A> caching. Servers discard cached
+ records whose TTL expires</DD>
+<DT><A name="tunnel">Tunnel mode</A></DT>
+<DD>An IPsec application in which an IPsec gateway provides protection
+ for packets to and from other systems. Contrast with<A href="#transport">
+ transport mode</A>.</DD>
+<DT><A name="2key">Two-key Triple DES</A></DT>
+<DD>A variant of<A href="#3DES"> triple DES or 3DES</A> in which only
+ two keys are used. As in the three-key version, the order of operations
+ is<A href="#EDE"> EDE</A> or encrypt-decrypt-encrypt, but in the
+ two-key variant the first and third keys are the same.
+<P>3DES with three keys has 3*56 = 168 bits of key but has only 112-bit
+ strength against a<A href="#meet"> meet-in-the-middle</A> attack, so it
+ is possible that the two key version is just as strong. Last I looked,
+ this was an open question in the research literature.</P>
+<P>RFC 2451 defines triple DES for<A href="#IPSEC"> IPsec</A> as the
+ three-key variant. The two-key variant should not be used and is not
+ implemented directly in<A href="#FreeSWAN"> Linux FreeS/WAN</A>. It
+ cannot be used in automatically keyed mode without major fiddles in the
+ source code. For manually keyed connections, you could make Linux
+ FreeS/WAN talk to a two-key implementation by setting two keys the same
+ in /etc/ipsec.conf.</P>
+</DD>
+<DT><A name="U">U</A></DT>
+<DT><A name="V">V</A></DT>
+<DT><A name="virtual">Virtual Interface</A></DT>
+<DD>A<A href="#Linux"> Linux</A> feature which allows one physical
+ network interface to have two or more IP addresses. See the<CITE> Linux
+ Network Administrator's Guide</CITE> in<A href="#kirch"> book form</A>
+ or<A href="http://metalab.unc.edu/LDP/LDP/nag/node1.html"> on the web</A>
+ for details.</DD>
+<DT>Virtual Private Network</DT>
+<DD>see<A href="#VPN"> VPN</A></DD>
+<DT><A name="VPN">VPN</A></DT>
+<DD><B>V</B>irtual<B> P</B>rivate<B> N</B>etwork, a network which can
+ safely be used as if it were private, even though some of its
+ communication uses insecure connections. All traffic on those
+ connections is encrypted.
+<P><A href="#IPSEC">IPsec</A> is not the only technique available for
+ building VPNs, but it is the only method defined by<A href="#RFC"> RFCs</A>
+ and supported by many vendors. VPNs are by no means the only thing you
+ can do with IPsec, but they may be the most important application for
+ many users.</P>
+</DD>
+<DT><A name="VPNC">VPNC</A></DT>
+<DD><A href="http://www.vpnc.org">Virtual Private Network Consortium</A>
+, an association of vendors of VPN products.</DD>
+<DT><A name="W">W</A></DT>
+<DT><A name="Wassenaar.gloss">Wassenaar Arrangement</A></DT>
+<DD>An international agreement restricting export of munitions and other
+ tools of war. Unfortunately, cryptographic software is also restricted
+ under the current version of the agreement.<A href="#Wassenaar">
+ Discussion</A>.</DD>
+<DT><A name="web">Web of Trust</A></DT>
+<DD><A href="#PGP">PGP</A>'s method of certifying keys. Any user can
+ sign a key; you decide which signatures or combinations of signatures
+ to accept as certification. This contrasts with the hierarchy of<A href="#CA">
+ CAs (Certification Authorities)</A> used in many<A href="#PKI"> PKIs
+ (Public Key Infrastructures)</A>.
+<P>See<A href="#GTR"> Global Trust Register</A> for an interesting
+ addition to the web of trust.</P>
+</DD>
+<DT><A name="WEP">WEP (Wired Equivalent Privacy)</A></DT>
+<DD>The cryptographic part of the<A href="#IEEE"> IEEE</A> standard for
+ wireless LANs. As the name suggests, this is designed to be only as
+ secure as a normal wired ethernet. Anyone with a network conection can
+ tap it. Its advocates would claim this is good design, refusing to
+ build in complex features beyond the actual requirements.
+<P>Critics refer to WEP as &quot;Wire<EM>tap</EM> Equivalent Privacy&quot;, and
+ consider it a horribly flawed design based on bogus &quot;requirements&quot;. You
+ do not control radio waves as you might control your wires, so the
+ metaphor in the rationale is utterly inapplicable. A security policy
+ that chooses not to invest resources in protecting against certain
+ attacks which can only be conducted by people physically plugged into
+ your LAN may or may not be reasonable. The same policy is completely
+ unreasonable when someone can &quot;plug in&quot; from a laptop half a block
+ away..</P>
+<P>There has been considerable analysis indicating that WEP is seriously
+ flawed. A FAQ on attacks against WEP is available. Part of it reads:</P>
+<BLOCKQUOTE> ... attacks are practical to mount using only inexpensive
+ off-the-shelf equipment. We recommend that anyone using an 802.11
+ wireless network not rely on WEP for security, and employ other
+ security measures to protect their wireless network. Note that our
+ attacks apply to both 40-bit and the so-called 128-bit versions of WEP
+ equally well.</BLOCKQUOTE>
+<P>WEP appears to be yet another instance of governments, and
+ unfortunately some vendors and standards bodies, deliberately promoting
+ hopelessly flawed &quot;security&quot; products, apparently mainly for the
+ benefit of eavesdropping agencies. See this<A href="#weak"> discussion</A>
+.</P>
+</DD>
+<DT><A name="X">X</A></DT>
+<DT><A name="X509">X.509</A></DT>
+<DD>A standard from the<A href="http://www.itu.int"> ITU (International
+ Telecommunication Union)</A>, for hierarchical directories with
+ authentication services, used in many<A href="#PKI"> PKI</A>
+ implementations.
+<P>Use of X.509 services, via the<A href="#LDAP"> LDAP protocol</A>, for
+ certification of keys is allowed but not required by the<A href="#IPSEC">
+ IPsec</A> RFCs. It is not yet implemented in<A href="#FreeSWAN"> Linux
+ FreeS/WAN</A>.</P>
+</DD>
+<DT>Xedia</DT>
+<DD>A vendor of router and Internet access products, now part of Lucent.
+ Their QVPN products interoperate with Linux FreeS/WAN; see our<A href="#xedia">
+ interop document</A>.</DD>
+<DT><A name="Y">Y</A></DT>
+<DT><A name="Z">Z</A></DT>
+</DL>
+<HR>
+<H1><A name="biblio">Bibliography for the Linux FreeS/WAN project</A></H1>
+<P>For extensive bibliographic links, see the<A href="http://liinwww.ira.uka.de/bibliography/index.html">
+ Collection of Computer Science Bibliographies</A></P>
+<P>See our<A href="web.html"> web links</A> for material available
+ online.</P>
+<HR><A name="adams"> Carlisle Adams and Steve Lloyd<CITE> Understanding
+ Public Key Infrastructure</CITE>
+<BR></A> Macmillan 1999 ISBN 1-57870-166-x
+<P>An overview, mainly concentrating on policy and strategic issues
+ rather than the technical details. Both authors work for<A href="#PKI">
+ PKI</A> vendor<A href="http://www.entrust.com/"> Entrust</A>.</P>
+<HR><A name="DNS.book"> Albitz, Liu &amp; Loukides<CITE> DNS &amp; BIND</CITE>
+ 3rd edition
+<BR></A> O'Reilly 1998 ISBN 1-56592-512-2
+<P>The standard reference on the<A href="#DNS"> Domain Name Service</A>
+ and<A href="#BIND"> Berkeley Internet Name Daemon</A>.</P>
+<HR><A name="anderson"> Ross Anderson</A>,<CITE> Security Engineering -
+ a Guide to Building Dependable Distributed Systems</CITE>
+<BR> Wiley, 2001, ISBN 0471389226
+<P>Easily the best book for the security professional I have seen.<STRONG>
+ Highly recommended</STRONG>. See the<A href="http://www.cl.cam.ac.uk/~rja14/book.html">
+ book web page</A>.</P>
+<P>This is quite readable, but Schneier's<A href="#secrets"> Secrets and
+ Lies</A> might be an easier introduction.</P>
+<HR><A name="puzzle"> Bamford<CITE> The Puzzle Palace, A report on NSA,
+ Americas's most Secret Agency</CITE>
+<BR> Houghton Mifflin 1982 ISBN 0-395-31286-8</A>
+<HR> Bamford<CITE> Body of Secrets</CITE>
+<P>The sequel.</P>
+<HR><A name="bander"> David Bander</A>,<CITE> Linux Security Toolkit</CITE>
+<BR> IDG Books, 2000, ISBN: 0764546902
+<P>This book has a short section on FreeS/WAN and includes Caldera Linux
+ on CD.</P>
+<HR><A name="CZR"> Chapman, Zwicky &amp; Russell</A>,<CITE> Building
+ Internet Firewalls</CITE>
+<BR> O'Reilly 1995 ISBN 1-56592-124-0
+<HR><A name="firewall.book"> Cheswick and Bellovin</A><CITE> Firewalls
+ and Internet Security: Repelling the Wily Hacker</CITE>
+<BR> Addison-Wesley 1994 ISBN 0201633574
+<P>A fine book on firewalls in particular and security in general from
+ two of AT&amp;T's system adminstrators.</P>
+<P>Bellovin has also done a number of<A href="#papers"> papers</A> on
+ IPsec and co-authored a<A href="#applied"> paper</A> on a large
+ FreeS/WAN application.</P>
+<HR><A name="comer"> Comer<CITE> Internetworking with TCP/IP</CITE>
+<BR> Prentice Hall</A>
+<UL>
+<LI>Vol. I: Principles, Protocols, &amp; Architecture, 3rd Ed. 1995
+ ISBN:0-13-216987-8</LI>
+<LI>Vol. II: Design, Implementation, &amp; Internals, 2nd Ed. 1994
+ ISBN:0-13-125527-4</LI>
+<LI>Vol. III: Client/Server Programming &amp; Applications
+<UL>
+<LI>AT&amp;T TLI Version 1994 ISBN:0-13-474230-3</LI>
+<LI>BSD Socket Version 1996 ISBN:0-13-260969-X</LI>
+<LI>Windows Sockets Version 1997 ISBN:0-13-848714-6</LI>
+</UL>
+</LI>
+</UL>
+<P>If you need to deal with the details of the network protocols, read
+ either this series or the<A href="#stevens"> Stevens and Wright</A>
+ series before you start reading the RFCs.</P>
+<HR><A name="diffie"> Diffie and Landau</A><CITE> Privacy on the Line:
+ The Politics of Wiretapping and Encryption</CITE>
+<BR> MIT press 1998 ISBN 0-262-04167-7 (hardcover) or 0-262-54100-9
+<BR>
+<HR><A name="d_and_hark"> Doraswamy and Harkins<CITE> IP Sec: The New
+ Security Standard for the Internet, Intranets and Virtual Private
+ Networks</CITE>
+<BR> Prentice Hall 1999 ISBN: 0130118982</A>
+<HR><A name="EFF"> Electronic Frontier Foundation<CITE> Cracking DES:
+ Secrets of Encryption Research, Wiretap Politics and Chip Design</CITE>
+<BR></A> O'Reilly 1998 ISBN 1-56592-520-3
+<P>To conclusively demonstrate that DES is inadequate for continued use,
+ the<A href="#EFF"> EFF</A> built a machine for just over $200,000 that
+ breaks DES encryption in under five days on average, under nine in the
+ worst case.</P>
+<P>The book provides details of their design and, perhaps even more
+ important, discusses why they felt the project was necessary.
+ Recommended for anyone interested in any of the three topics mentioned
+ in the subtitle.</P>
+<P>See also the<A href="http://www.eff.org/descracker.html"> EFF page on
+ this project</A> and our discussion of<A href="#desnotsecure"> DES
+ insecurity</A>.</P>
+<HR> Martin Freiss<CITE> Protecting Networks with SATAN</CITE>
+<BR> O'Reilly 1998 ISBN 1-56592-425-8
+<BR> translated from a 1996 work in German
+<P>SATAN is a Security Administrator's Tool for Analysing Networks. This
+ book is a tutorial in its use.</P>
+<HR> Gaidosch and Kunzinger<CITE> A Guide to Virtual Private Networks</CITE>
+<BR> Prentice Hall 1999 ISBN: 0130839647
+<HR><A name="Garfinkel"> Simson Garfinkel</A><CITE> Database Nation: the
+ death of privacy in the 21st century</CITE>
+<BR> O'Reilly 2000 ISBN 1-56592-653-6
+<P>A thoughtful and rather scary book.</P>
+<HR><A name="PGP"> Simson Garfinkel</A><CITE> PGP: Pretty Good Privacy</CITE>
+<BR> O'Reilly 1995 ISBN 1-56592-098-8
+<P>An excellent introduction and user manual for the<A href="#PGP"> PGP</A>
+ email-encryption package. PGP is a good package with a complex and
+ poorly-designed user interface. This book or one like it is a must for
+ anyone who has to use it at length.</P>
+<P>The book covers using PGP in Unix, PC and Macintosh environments,
+ plus considerable background material on both the technical and
+ political issues around cryptography.</P>
+<P>The book is now seriously out of date. It does not cover recent
+ developments such as commercial versions since PGP 5, the Open PGP
+ standard or GNU PG..</P>
+<HR><A name="practical"> Garfinkel and Spafford</A><CITE> Practical Unix
+ Security</CITE>
+<BR> O'Reilly 1996 ISBN 1-56592-148-8
+<P>A standard reference.</P>
+<P>Spafford's web page has an excellent collection of<A href="http://www.cs.purdue.edu/coast/hotlist">
+ crypto and security links</A>.</P>
+<HR><A name="Kahn"> David Kahn</A><CITE> The Codebreakers: the
+ Comprehensive History of Secret Communications from Ancient Times to
+ the Internet</CITE>
+<BR> second edition Scribner 1996 ISBN 0684831309
+<P>A history of codes and code-breaking from ancient Egypt to the 20th
+ century. Well-written and exhaustively researched.<STRONG> Highly
+ recommended</STRONG>, even though it does not have much on computer
+ cryptography.</P>
+<HR> David Kahn<CITE> Seizing the Enigma, The Race to Break the German
+ U-Boat codes, 1939-1943</CITE>
+<BR> Houghton Mifflin 1991 ISBN 0-395-42739-8
+<HR><A name="kirch"> Olaf Kirch</A><CITE> Linux Network Administrator's
+ Guide</CITE>
+<BR> O'Reilly 1995 ISBN 1-56592-087-2
+<P>Now becoming somewhat dated in places, but still a good introductory
+ book and general reference.</P>
+<HR><A name="LinVPN"> Kolesnikov and Hatch</A>,<CITE> Building Linux
+ Virtual Private Networks (VPNs)</CITE>
+<BR> New Riders 2002
+<P>This has had a number of favorable reviews, including<A href="http://www.slashdot.org/article.pl?sid=02/02/27/0115214&amp;mode=thread&amp;tid=172">
+ this one</A> on Slashdot. The book has a<A href="http://www.buildinglinuxvpns.net/">
+ web site</A>.</P>
+<HR><A name="RFCs"> Pete Loshin<CITE> Big Book of IPsec RFCs</CITE>
+<BR> Morgan Kaufmann 2000 ISBN: 0-12-455839-9</A>
+<HR><A name="crypto"> Steven Levy<CITE> Crypto: How the Code Rebels Beat
+ the Government -- Saving Privacy in the Digital Age</CITE></A>
+<BR> Penguin 2001, ISBN 0-670--85950-8
+<P><STRONG>Highly recommended</STRONG>. A fine history of recent (about
+ 1970-2000) developments in the field, and the related political
+ controversies. FreeS/WAN project founder and leader John Gilmore
+ appears several times.</P>
+<P>The book does not cover IPsec or FreeS/WAN, but this project is very
+ much another battle in the same war. See our discussion of the<A href="politics.html">
+ politics</A>.</P>
+<HR><A name="GTR"> Matyas, Anderson et al.</A><CITE> The Global Trust
+ Register</CITE>
+<BR> Northgate Consultants Ltd 1998 ISBN: 0953239705
+<BR> hard cover edition MIT Press 1999 ISBN 0262511053
+<P>From<A href="http://www.cl.cam.ac.uk/Research/Security/Trust-Register">
+ their web page:</A></P>
+<BLOCKQUOTE> This book is a register of the fingerprints of the world's
+ most important public keys; it implements a top-level certification
+ authority (CA) using paper and ink rather than in an electronic system.</BLOCKQUOTE>
+<HR><A name="handbook"> Menezies, van Oorschot and Vanstone<CITE>
+ Handbook of Applied Cryptography</CITE></A>
+<BR> CRC Press 1997
+<BR> ISBN 0-8493-8523-7
+<P>An excellent reference. Read<A href="#schneier"> Schneier</A> before
+ tackling this.</P>
+<HR> Michael Padlipsky<CITE> Elements of Networking Style</CITE>
+<BR> Prentice-Hall 1985 ISBN 0-13-268111-0 or 0-13-268129-3
+<P>Probably<STRONG> the funniest technical book ever written</STRONG>,
+ this is a vicious but well-reasoned attack on the OSI &quot;seven layer
+ model&quot; and all that went with it. Several chapters of it are also
+ available as RFCs 871 to 875.</P>
+<HR><A name="matrix"> John S. Quarterman</A><CITE> The Matrix: Computer
+ Networks and Conferencing Systems Worldwide</CITE>
+<BR> Digital Press 1990 ISBN 155558-033-5
+<BR> Prentice-Hall ISBN 0-13-565607-9
+<P>The best general treatment of computer-mediated communication we have
+ seen. It naturally has much to say about the Internet, but also covers
+ UUCP, Fidonet and so on.</P>
+<HR><A name="ranch"> David Ranch</A><CITE> Securing Linux Step by Step</CITE>
+<BR> SANS Institute, 1999
+<P><A href="http://www.sans.org/">SANS</A> is a respected organisation,
+ this guide is part of a well-known series, and Ranch has previously
+ written the useful<A href=" http://www.ecst.csuchico.edu/~dranch/LINUX/index-linux.html#trinityos">
+ Trinity OS</A> guide to securing Linux, so my guess would be this is a
+ pretty good book. I haven't read it yet, so I'm not certain. It can be
+ ordered online from<A href="http://www.sans.org/"> SANS</A>.</P>
+<P>Note (Mar 1, 2002): a new edition with different editors in the
+ works. Expect it this year.</P>
+<HR><A name="schneier"> Bruce Schneier</A><CITE> Applied Cryptography,
+ Second Edition</CITE>
+<BR> John Wiley &amp; Sons, 1996
+<BR> ISBN 0-471-12845-7 hardcover
+<BR> ISBN 0-471-11709-9 paperback
+<P>A standard reference on computer cryptography. For more recent
+ essays, see the<A href="http://www.counterpane.com/"> author's
+ company's web site</A>.</P>
+<HR><A name="secrets"> Bruce Schneier</A><CITE> Secrets and Lies</CITE>
+<BR> Wiley 2000, ISBN 0-471-25311-1
+<P>An interesting discussion of security and privacy issues, written
+ with more of an &quot;executive overview&quot; approach rather than a narrow
+ focus on the technical issues.<STRONG> Highly recommended</STRONG>.</P>
+<P>This is worth reading even if you already understand security issues,
+ or think you do. To go deeper, follow it with Anderson's<A href="#anderson">
+ Security Engineering</A>.</P>
+<HR><A name="VPNbook"> Scott, Wolfe and Irwin<CITE> Virtual Private
+ Networks</CITE></A>
+<BR> 2nd edition, O'Reilly 1999 ISBN: 1-56592-529-7
+<P>This is the only O'Reilly book, out of a dozen I own, that I'm
+ disappointed with. It deals mainly with building VPNs with various
+ proprietary tools --<A href="#PPTP"> PPTP</A>,<A href="#ssh"> SSH</A>,
+ Cisco PIX, ... -- and touches only lightly on IPsec-based approaches.</P>
+<P>That said, it appears to deal competently with what it does cover and
+ it has readable explanations of many basic VPN and security concepts.
+ It may be exactly what some readers require, even if I find the
+ emphasis unfortunate.</P>
+<HR><A name="LASG"> Kurt Seifried<CITE> Linux Administrator's Security
+ Guide</CITE></A>
+<P>Available online from<A href="http://www.securityportal.com/lasg/">
+ Security Portal</A>. It has fairly extensive coverage of IPsec.</P>
+<HR><A name="Smith"> Richard E Smith<CITE> Internet Cryptography</CITE>
+<BR></A> ISBN 0-201-92480-3, Addison Wesley, 1997
+<P>See the book's<A href="http://www.visi.com/crypto/inet-crypto/index.html">
+ home page</A></P>
+<HR><A name="neal"> Neal Stephenson<CITE> Cryptonomicon</CITE></A>
+<BR> Hardcover ISBN -380-97346-4, Avon, 1999.
+<P>A novel in which cryptography and the net figure prominently.<STRONG>
+ Highly recommended</STRONG>: I liked it enough I immediately went out
+ and bought all the author's other books.</P>
+<P>There is also a paperback edition. Sequels are expected.</P>
+<HR><A name="stevens"> Stevens and Wright</A><CITE> TCP/IP Illustrated</CITE>
+<BR> Addison-Wesley
+<UL>
+<LI>Vol. I: The Protocols 1994 ISBN:0-201-63346-9</LI>
+<LI>Vol. II: The Implementation 1995 ISBN:0-201-63354-X</LI>
+<LI>Vol. III: TCP for Transactions, HTTP, NNTP, and the UNIX Domain
+ Protocols 1996 ISBN: 0-201-63495-3</LI>
+</UL>
+<P>If you need to deal with the details of the network protocols, read
+ either this series or the<A href="#comer"> Comer</A> series before you
+ start reading the RFCs.</P>
+<HR><A name="Rubini"> Rubini</A><CITE> Linux Device Drivers</CITE>
+<BR> O'Reilly &amp; Associates, Inc. 1998 ISBN 1-56592-292-1
+<HR><A name="Zeigler"> Robert Zeigler</A><CITE> Linux Firewalls</CITE>
+<BR> Newriders Publishing, 2000 ISBN 0-7537-0900-9
+<P>A good book, with detailed coverage of ipchains(8) firewalls and of
+ many related issues.</P>
+<HR>
+<H1><A name="RFC">IPsec RFCs and related documents</A></H1>
+<H2><A name="RFCfile">The RFCs.tar.gz Distribution File</A></H2>
+<P>The Linux FreeS/WAN distribution is available from<A href="http://www.xs4all.nl/~freeswan">
+ our primary distribution site</A> and various mirror sites. To give
+ people more control over their downloads, the RFCs that define IP
+ security are bundled separately in the file RFCs.tar.gz.</P>
+<P>The file you are reading is included in the main distribution and is
+ available on the web site. It describes the RFCs included in the<A href="#RFCs.tar.gz">
+ RFCs.tar.gz</A> bundle and gives some pointers to<A href="#sources">
+ other ways to get them</A>.</P>
+<H2><A name="sources">Other sources for RFCs &amp; Internet drafts</A></H2>
+<H3><A name="RFCdown">RFCs</A></H3>
+<P>RFCs are downloadble at many places around the net such as:</P>
+<UL>
+<LI><A href="http://www.rfc-editor.org">http://www.rfc-editor.org</A></LI>
+<LI><A href="http://nis.nsf.net/internet/documents/rfc">NSF.net</A></LI>
+<LI><A href="http://sunsite.doc.ic.ac.uk/computing/internet/rfc">Sunsite
+ in the UK</A></LI>
+</UL>
+<P>browsable in HTML form at others such as:</P>
+<UL>
+<LI><A href="http://www.landfield.com/rfcs/index.html">landfield.com</A></LI>
+<LI><A href="http://www.library.ucg.ie/Connected/RFC">Connected Internet
+ Encyclopedia</A></LI>
+</UL>
+<P>and some of them are available in translation:</P>
+<UL>
+<LI><A href="http://www.eisti.fr/eistiweb/docs/normes/">French</A></LI>
+</UL>
+<P>There is also a published<A href="#RFCs"> Big Book of IPSEC RFCs</A>.</P>
+<H3><A name="drafts">Internet Drafts</A></H3>
+<P>Internet Drafts, working documents which sometimes evolve into RFCs,
+ are also available.</P>
+<UL>
+<LI><A href="http://www.ietf.org/ID.html">Overall reference page</A></LI>
+<LI><A href="http://www.ietf.org/ids.by.wg/ipsec.html">IPsec</A> working
+ group</LI>
+<LI><A href="http://www.ietf.org/ids.by.wg/ipsra.html">IPSRA (IPsec
+ Remote Access)</A> working group</LI>
+<LI><A href="http://www.ietf.org/ids.by.wg/ipsp.html">IPsec Policy</A>
+ working group</LI>
+<LI><A href="http://www.ietf.org/ids.by.wg/kink.html">KINK (Kerberized
+ Internet Negotiation of Keys)</A> working group</LI>
+</UL>
+<P>Note: some of these may be obsolete, replaced by later drafts or by
+ RFCs.</P>
+<H3><A name="FIPS1">FIPS standards</A></H3>
+<P>Some things used by<A href="#IPSEC"> IPsec</A>, such as<A href="#DES">
+ DES</A> and<A href="#SHA"> SHA</A>, are defined by US government
+ standards called<A href="#FIPS"> FIPS</A>. The issuing organisation,<A href="#NIST">
+ NIST</A>, have a<A href="http://www.itl.nist.gov/div897/pubs"> FIPS
+ home page</A>.</P>
+<H2><A name="RFCs.tar.gz">What's in the RFCs.tar.gz bundle?</A></H2>
+<P>All filenames are of the form rfc*.txt, with the * replaced with the
+ RFC number.</P>
+<PRE>RFC#        Title</PRE>
+<H3><A name="rfc.ov">Overview RFCs</A></H3>
+<PRE>2401        Security Architecture for the Internet Protocol
+2411        IP Security Document Roadmap</PRE>
+<H3><A name="basic.prot">Basic protocols</A></H3>
+<PRE>2402        IP Authentication Header
+2406        IP Encapsulating Security Payload (ESP)</PRE>
+<H3><A name="key.ike">Key management</A></H3>
+<PRE>2367        PF_KEY Key Management API, Version 2
+2407        The Internet IP Security Domain of Interpretation for ISAKMP
+2408        Internet Security Association and Key Management Protocol (ISAKMP)
+2409        The Internet Key Exchange (IKE)
+2412        The OAKLEY Key Determination Protocol
+2528        Internet X.509 Public Key Infrastructure</PRE>
+<H3><A name="rfc.detail">Details of various things used</A></H3>
+<PRE>2085        HMAC-MD5 IP Authentication with Replay Prevention
+2104        HMAC: Keyed-Hashing for Message Authentication
+2202        Test Cases for HMAC-MD5 and HMAC-SHA-1
+2207        RSVP Extensions for IPSEC Data Flows
+2403        The Use of HMAC-MD5-96 within ESP and AH
+2404        The Use of HMAC-SHA-1-96 within ESP and AH
+2405        The ESP DES-CBC Cipher Algorithm With Explicit IV
+2410        The NULL Encryption Algorithm and Its Use With IPsec
+2451        The ESP CBC-Mode Cipher Algorithms
+2521        ICMP Security Failures Messages</PRE>
+<H3><A name="rfc.ref">Older RFCs which may be referenced</A></H3>
+<PRE>1321        The MD5 Message-Digest Algorithm
+1828        IP Authentication using Keyed MD5
+1829        The ESP DES-CBC Transform
+1851        The ESP Triple DES Transform
+1852        IP Authentication using Keyed SHA</PRE>
+<H3><A name="rfc.dns">RFCs for secure DNS service, which IPsec may use</A>
+</H3>
+<PRE>2137        Secure Domain Name System Dynamic Update
+2230        Key Exchange Delegation Record for the DNS
+2535        Domain Name System Security Extensions
+2536        DSA KEYs and SIGs in the Domain Name System (DNS)
+2537        RSA/MD5 KEYs and SIGs in the Domain Name System (DNS)
+2538        Storing Certificates in the Domain Name System (DNS)
+2539        Storage of Diffie-Hellman Keys in the Domain Name System (DNS)</PRE>
+<H3><A name="rfc.exp">RFCs labelled &quot;experimental&quot;</A></H3>
+<PRE>2521        ICMP Security Failures Messages
+2522        Photuris: Session-Key Management Protocol
+2523        Photuris: Extended Schemes and Attributes</PRE>
+<H3><A name="rfc.rel">Related RFCs</A></H3>
+<PRE>1750        Randomness Recommendations for Security
+1918        Address Allocation for Private Internets
+1984        IAB and IESG Statement on Cryptographic Technology and the Internet
+2144        The CAST-128 Encryption Algorithm</PRE>
+<HR>
+<H1><A name="roadmap">Distribution Roadmap: What's Where in Linux
+ FreeS/WAN</A></H1>
+<P> This file is a guide to the locations of files within the FreeS/WAN
+ distribution. Everything described here should be on your system once
+ you download, gunzip, and untar the distribution.</P>
+<P>This distribution contains two major subsystems</P>
+<DL>
+<DT><A href="#klips.roadmap">KLIPS</A></DT>
+<DD>the kernel code</DD>
+<DT><A href="#pluto.roadmap">Pluto</A></DT>
+<DD>the user-level key-management daemon</DD>
+</DL>
+<P>plus assorted odds and ends.</P>
+<H2><A name="top">Top directory</A></H2>
+<P>The top directory has essential information in text files:</P>
+<DL>
+<DT>README</DT>
+<DD>introduction to the software</DD>
+<DT>INSTALL</DT>
+<DD>short experts-only installation procedures. More detalied procedures
+ are in<A href="install.html"> installation</A> and<A href="config.html">
+ configuration</A> HTML documents.</DD>
+<DT>BUGS</DT>
+<DD>major known bugs in the current release.</DD>
+<DT>CHANGES</DT>
+<DD>changes from previous releases</DD>
+<DT>CREDITS</DT>
+<DD>acknowledgement of contributors</DD>
+<DT>COPYING</DT>
+<DD>licensing and distribution information</DD>
+</DL>
+<H2><A name="doc">Documentation</A></H2>
+<P> The doc directory contains the bulk of the documentation, most of it
+ in HTML format. See the<A href="index.html"> index file</A> for
+ details.</P>
+<H2><A name="klips.roadmap">KLIPS: kernel IP security</A></H2>
+<P><A href="#KLIPS"> KLIPS</A> is<STRONG> K</STRONG>erne<STRONG>L</STRONG><STRONG>
+ IP</STRONG><STRONG> S</STRONG>ecurity. It lives in the klips directory,
+ of course.</P>
+<DL>
+<DT>klips/doc</DT>
+<DD>documentation</DD>
+<DT>klips/patches</DT>
+<DD>patches for existing kernel files</DD>
+<DT>klips/test</DT>
+<DD>test stuff</DD>
+<DT>klips/utils</DT>
+<DD>low-level user utilities</DD>
+<DT>klips/net/ipsec</DT>
+<DD>actual klips kernel files</DD>
+<DT>klips/src</DT>
+<DD>symbolic link to klips/net/ipsec
+<P>The &quot;make insert&quot; step of installation installs the patches and makes
+ a symbolic link from the kernel tree to klips/net/ipsec. The odd name
+ of klips/net/ipsec is dictated by some annoying limitations of the
+ scripts which build the Linux kernel. The symbolic-link business is a
+ bit messy, but all the alternatives are worse.</P>
+<P></P>
+</DD>
+<DT>klips/utils</DT>
+<DD>Utility programs:
+<P></P>
+<DL>
+<DT>eroute</DT>
+<DD>manipulate IPsec extended routing tables</DD>
+<DT>klipsdebug</DT>
+<DD>set Klips (kernel IPsec support) debug features and level</DD>
+<DT>spi</DT>
+<DD>manage IPsec Security Associations</DD>
+<DT>spigrp</DT>
+<DD>group/ungroup IPsec Security Associations</DD>
+<DT>tncfg</DT>
+<DD>associate IPsec virtual interface with real interface</DD>
+</DL>
+<P>These are all normally invoked by ipsec(8) with commands such as</P>
+<PRE>        ipsec tncfg <VAR>arguments</VAR></PRE>
+ There are section 8 man pages for all of these; the names have &quot;ipsec_&quot;
+ as a prefix, so your man command should be something like:
+<PRE>        man 8 ipsec_tncfg</PRE>
+</DD>
+</DL>
+<H2><A name="pluto.roadmap">Pluto key and connection management daemon</A>
+</H2>
+<P><A href="#Pluto"> Pluto</A> is our key management and negotiation
+ daemon. It lives in the pluto directory, along with its low-level user
+ utility, whack.</P>
+<P> There are no subdirectories. Documentation is a man page,<A href="manpage.d/ipsec_pluto.8.html">
+ pluto.8</A>. This covers whack as well.</P>
+<H2><A name="utils">Utils</A></H2>
+<P> The utils directory contains a growing collection of higher-level
+ user utilities, the commands that administer and control the software.
+ Most of the things that you will actually have to run yourself are in
+ there.</P>
+<DL>
+<DT>ipsec</DT>
+<DD>invoke IPsec utilities
+<P>ipsec(8) is normally the only program installed in a standard
+ directory, /usr/local/sbin. It is used to invoke the others, both those
+ listed below and the ones in klips/utils mentioned above.</P>
+<P></P>
+</DD>
+<DT>auto</DT>
+<DD>control automatically-keyed IPsec connections</DD>
+<DT>manual</DT>
+<DD>take manually-keyed IPsec connections up and down</DD>
+<DT>barf</DT>
+<DD>generate copious debugging output</DD>
+<DT>look</DT>
+<DD>generate moderate amounts of debugging output</DD>
+</DL>
+<P> There are .8 manual pages for these. look is covered in barf.8. The
+ man pages have an &quot;ipsec_&quot; prefix so your man command should be
+ something like:</P>
+<PRE>
+        man 8 ipsec_auto
+</PRE>
+<P> Examples are in various files with names utils/*.eg</P>
+<H2><A name="lib">Libraries</A></H2>
+<H3><A name="fswanlib">FreeS/WAN Library</A></H3>
+<P> The lib directory is the FreeS/WAN library, also steadily growing,
+ used by both user-level and kernel code.
+<BR /> It includes section 3<A href="manpages.html"> man pages</A> for
+ the library routines.</P>
+<H3><A name="otherlib">Imported Libraries</A></H3>
+<H4><A NAME="33_6_2_1">LibDES</A></H4>
+ The libdes library, originally from SSLeay, is used by both Klips and
+ Pluto for<A href="#3DES"> Triple DES</A> encryption. Single DES is not
+ used because<A href="#desnotsecure"> it is insecure</A>.
+<P> Note that this library has its own license, different from the<A href="#GPL">
+ GPL</A> used for other code in FreeS/WAN.</P>
+<P> The library includes its own documentation.</P>
+<H4><A NAME="33_6_2_2">GMP</A></H4>
+ The GMP (GNU multi-precision) library is used for multi-precision
+ arithmetic in Pluto's key-exchange code and public key code.
+<P> Older versions (up to 1.7) of FreeS/WAN included a copy of this
+ library in the FreeS/WAN distribution.</P>
+<P> Since 1.8, we have begun to rely on the system copy of GMP.</P>
+<HR>
+<H1><A name="umltesting">User-Mode-Linux Testing guide</A></H1>
+<P> User mode linux is a way to compile a linux kernel such that it can
+ run as a process in another linux system (potentially as a *BSD or
+ Windows process later). See<A HREF="http://user-mode-linux.sourceforge.net/">
+ http://user-mode-linux.sourceforge.net/</A></P>
+<P> UML is a good platform for testing and experimenting with FreeS/WAN.
+ It allows several network nodes to be simulated on a single machine.
+ Creating, configuring, installing, monitoring, and controling these
+ nodes is generally easier and easier to script with UML than real
+ hardware.</P>
+<P> You'll need about 500Mb of disk space for a full
+ sunrise-east-west-sunset setup. You can possibly get this down by 130Mb
+ if you remove the sunrise/sunset kernel build. If you just want to run,
+ then you can even remove the east/west kernel build.</P>
+<P> Nothing need be done as super user. In a couple of steps, we note
+ where super user is required to install commands in system-wide
+ directories, but ~/bin could be used instead. UML seems to use a
+ system-wide /tmp/uml directory so different users may interfere with
+ one another. Later UMLs use ~/.uml instead, so multiple users running
+ UML tests should not be a problem, but note that a single user running
+ the UML tests will only be able run one set. Further, UMLs sometimes
+ get stuck and hang around. These &quot;zombies&quot; (most will actually be in
+ the &quot;T&quot; state in the process table) will interfere with subsequent
+ tests.</P>
+<H2><A NAME="34_1">Preliminary Notes on BIND</A></H2>
+<P> As of 2003/3/1, the Light-Weight Resolver is used by pluto. This
+ requires that BIND9 be running. It also requires that BIND9 development
+ libraries be present in the build environment. The DNSSEC code is only
+ truly functional in BIND9 snapshots. The library code could be 9.2.2,
+ we believe. We are using BIND9 20021115 snapshot code from<A HREF="ftp://ftp.isc.org/isc/bind9/snapshots">
+ ftp://ftp.isc.org/isc/bind9/snapshots</A>.</P>
+<P> FreeS/WAN may well require a newer BIND than is on your system. Many
+ distributions have moved to BIND9.2.2 recently due to a security
+ advisory. BIND is five components.</P>
+<OL>
+<LI> named</LI>
+<LI> dnssec-*</LI>
+<LI> client side resolver libraries</LI>
+<LI> client side utility libraries I thought there were lib and named
+ parts to dnsssec...</LI>
+<LI> dynamic DNS update utilities</LI>
+</OL>
+<P> The only piece that we need for *building* is #4. That's the only
+ part that has to be on the build host. What is the difference between
+ resolver and util libs? If you want to edit
+ testing/baseconfigs/all/etc/bind, you'll need a snapshot version. The
+ resolver library contains the resolver. FreeS/WAN has its own copy of
+ that in lib/liblwres.</P>
+<H2><A NAME="34_2">Steps to Install UML for FreeS/WAN</A></H2>
+<OL>
+<LI> Get the following files:
+<OL type="a">
+<LI> from<A HREF="http://www.sandelman.ottawa.on.ca/freeswan/uml/">
+ http://www.sandelman.ottawa.on.ca/freeswan/uml/</A>
+ umlfreeroot-15.1.tar.gz (or highest numbered one). This is a debian
+ potato root file system. You can use this even on a Redhat host, as it
+ has the newer GLIBC2.2 libraries as well.
+<!-- If you are using
+  Redhat 7.2 or newer as your development machine, you can create the
+  image from your installation media. See <A HREF="uml-rhroot.html">Building a RedHat root"></A>.
+  A future document will explain how to build this from .DEB files as well.
+-->
+
+<!--
+<LI> umlfreesharemini.tar.gz    (or umlfreeshareall.tar.gz). 
+  If you are a Debian potato user, you don't need it you can use your
+  native /usr/share.
+</UL>
+-->
+</LI>
+<LI> From<A HREF="ftp://ftp.xs4all.nl/pub/crypto/freeswan/">
+ ftp://ftp.xs4all.nl/pub/crypto/freeswan/</A> a snapshot or release
+ (1.92 or better)</LI>
+<LI> From a<A HREF="http://www.kernel.org/mirrors/">
+ http://www.kernel.org mirror</A>, the virgin 2.4.19 kernel. Please
+ realize that we have defaults in our tree for kernel configuration. We
+ try to track the latest UML kernels. If you use a newer kernel, you may
+ have faults in the kernel build process. You can see what the latest
+ that is being regularly tested by visiting<A HREF="http://bugs.freeswan.org:81/regress/HEAD/lastgood/freeswan-regress-env.sh">
+ freeswan-regress-env.sh</A>.</LI>
+<LI>
+<!-- Note: this step is refered to as "step 1d" below. -->
+ Get<A HREF="http://ftp.nl.linux.org/uml/">
+ http://ftp.nl.linux.org/uml/</A> uml-patch-2.4.19-47.bz2 or the one
+ associated with your kernel. As of 2003/03/05, uml-patch-2.4.19-47.bz2
+ works for us.<STRONG> More recent versions of the patch have not been
+ tested by us.</STRONG></LI>
+<LI> You'll probably want to visit<A HREF="http://user-mode-linux.sourceforge.net">
+ http://user-mode-linux.sourceforge.net</A> and get the UML utilities.
+ These are not needed for the build or interactive use (but
+ recommended). They are necessary for the regression testing procedures
+ used by &quot;make check&quot;. We currently use uml_utilities_20020212.tar.bz2.</LI>
+<LI> You need tcpdump version 3.7.1 or better. This is newer than the
+ version included in most LINUX distributions. You can check the version
+ of an installed tcpdump with the --version flag. If you need a newer
+ tcpdump fetch both tcpdump and libpcap source tar files from<A HREF="http://www.tcpdump.org/">
+ http://www.tcpdump.org/</A> or a mirror.</LI>
+</OL>
+</LI>
+<LI> Pick a suitable place, and extract the following files:
+<OL type="a">
+<LI>
+<!-- Note: this step is refered to as "step 2a" later. -->
+ 2.4.19 kernel. For instance:
+<PRE>
+ <CODE>           cd /c2/kernel
+           tar xzvf ../download/pub/linux/kernel/v2.4/linux-2.4.19.tar.gz
+</CODE>
+</PRE>
+</LI>
+<LI> extract the umlfreeroot file
+<!-- (unless you <A HREF="uml-rhroot.html">built your own from RPMs</A>) -->
+
+<PRE>
+ <CODE>           mkdir -p /c2/user-mode-linux/basic-root
+           cd /c2/user-mode-linux/basic-root
+           tar xzvf ../download/umlfreeroot-15.1.tar.gz
+</CODE>
+</PRE>
+</LI>
+<LI> FreeSWAN itself (or checkout &quot;all&quot; from CVS)
+<PRE>
+ <CODE>           mkdir -p /c2/freeswan/sandbox
+           cd /c2/freeswan/sandbox
+           tar xzvf ../download/snapshot.tar.gz
+</CODE>
+</PRE>
+</LI>
+</OL>
+</LI>
+<LI> If you need to build a newer tcpdump:
+<UL>
+<LI> Make sure you have OpenSSL installed -- it is needed for
+ cryptographic routines.</LI>
+<LI> Unpack libpcap and tcpdump source in parallel directories (the
+ tcpdump build procedures look for libpcap next door).</LI>
+<LI> Change directory into the libpcap source directory and then build
+ the library:
+<PRE>
+ <CODE>	./configure
+	make
+</CODE>
+</PRE>
+</LI>
+<LI> Change into the tcpdump source directory, build tcpdump, and
+ install it.
+<PRE>
+ <CODE>	./configure
+	make
+	# Need to be superuser to install in system directories.
+	# Installing in ~/bin would be an alternative.
+	su -c &quot;make install&quot;
+</CODE>
+</PRE>
+</LI>
+</UL>
+</LI>
+<LI> If you need the uml utilities, unpack them somewhere then build and
+ install them:
+<PRE>
+ <CODE>	cd tools
+	make all
+	# Need to be superuser to install in system directories.
+	# Installing in ~/bin would be an alternative.
+	su -c &quot;make install BIN_DIR=/usr/local/bin&quot;
+</CODE>
+</PRE>
+</LI>
+<LI> set up the configuration file
+<UL>
+<LI> <CODE>cd /c2/freeswan/sandbox/freeswan-1.97/testing/utils</CODE></LI>
+<LI> copy umlsetup-sample.sh to ../../umlsetup.sh: <CODE> cp
+ umlsetup-sample.sh ../../umlsetup.sh</CODE></LI>
+<LI> open up ../../umlsetup.sh in your favorite editor.</LI>
+<LI> change POOLSPACE= to point to the place with at least 500Mb of
+ disk. Best if it is on the same partition as the &quot;umlfreeroot&quot;
+ extraction, as it will attempt to use hard links if possible to save
+ disk space.</LI>
+<LI> Set TESTINGROOT if you intend to run the script outside of the
+ sandbox/snapshot/release directory. Otherwise, it will configure
+ itself.</LI>
+<LI> KERNPOOL should point to the directory with your 2.4.19 kernel
+ tree. This tree should be unconfigured! This is the directory you used
+ in step 2a.</LI>
+<LI> UMLPATCH should point at the bz2 file you downloaded at 1d. If
+ using a kernel that already includes the patch, set this to /dev/null.</LI>
+<LI> FREESWANDIR should point at the directory where you unpacked the
+ snapshot/release. Include the &quot;freeswan-snap2001sep16b&quot; or whatever in
+ it. If you are running from CVS, then you point at the directory where
+ top, klips, etc. are. The script will fix up the directory so that it
+ can be used.</LI>
+<LI> BASICROOT should be set to the directory used in 2b, or to the
+ directory that you created with RPMs.</LI>
+<LI> SHAREDIR should be set to the directory used in 2c, to /usr/share
+ for Debian potato users, or to $BASICROOT/usr/share.</LI>
+</UL>
+</LI>
+<LI>
+<PRE> <CODE>cd $TESTINGROOT/utils
+sh make-uml.sh
+</CODE></PRE>
+ It will grind for awhile. If there are errors it will bail. If so, run
+ it under &quot;script&quot; and send the output to bugs@lists.freeswan.org.</LI>
+<LI> You will have a bunch of stuff under $POOLSPACE. Open four xterms:
+<PRE> <CODE>    for i in sunrise sunset east west
+    do
+        xterm -name $i -title $i -e $POOLSPACE/$i/start.sh     done
+</CODE></PRE>
+</LI>
+<LI> Login as root. Password is &quot;root&quot; (Note, these virtual machines are
+ networked together, but are not configured to talk to the rest of the
+ world.)</LI>
+<LI> verify that pluto started on east/west, run &quot;ipsec look&quot;</LI>
+<LI> login to sunrise. run &quot;ping sunset&quot;</LI>
+<LI> login to west. run &quot;tcpdump -p -i eth1 -n&quot; (tcpdump must be version
+ 3.7.1 or newer)</LI>
+<LI> Closing a console xterm will shut down that UML.</LI>
+<LI> You can &quot;make check&quot;, if you want to. It is run from
+ /c2/freeswan/sandbox/freeswan-1.97.</LI>
+</OL>
+<H1><A NAME="35">Debugging the kernel with GDB</A></H1>
+<P> With User-Mode-Linux, you can debug the kernel using GDB. See
+<!--HREF="http://user-mode-linux.sourceforge.net/debugging.html"-->
+
+ http://user-mode-linux.sourceforge.net/debugging.html.</(null)></P>
+<P> Typically, one will want to address a test case for a failing
+ situation. Running GDB from Emacs, or from other front ends is
+ possible. First start GDB.</P>
+<P> Tell it to open the UMLPOOL/swan/linux program.</P>
+<P> Note the PID of GDB:</P>
+<PRE>
+marajade-[projects/freeswan/mgmt/planning] mcr 1029 %ps ax | grep gdb
+ 1659 pts/9    SN     0:00 /usr/bin/gdb -fullname -cd /mara4/freeswan/kernpatch/UMLPOOL/swan/ linux
+</PRE>
+<P> Set the following in the environment:</P>
+<PRE>
+UML_east_OPT=&quot;debug gdb-pid=1659&quot;
+</PRE>
+<P> Then start the user-mode-linux in the test scheme you wish:</P>
+<PRE>
+marajade-[kernpatch/testing/klips/east-icmp-02] mcr 1220 %../../utils/runme.sh
+</PRE>
+ The user-mode-linux will stop on boot, giving you a chance to attach to
+ the process:
+<PRE>
+(gdb) file linux
+Reading symbols from linux...done.
+(gdb) attach 1
+Attaching to program: /mara4/freeswan/kernpatch/UMLPOOL/swan/linux, process 1
+0xa0118bc1 in kill () at hostfs_kern.c:770
+</PRE>
+<P> At this point, break points should be created as appropriate.</P>
+<H2><A NAME="35_1">Other notes about debugging</A></H2>
+<P> If you are running a standard test, after all the packets are sent,
+ the UML will be shutdown. This can cause problems, because the UML may
+ get terminated while you are debugging.</P>
+<P> The environment variable <CODE>NETJIGWAITUSER</CODE> can be set to
+ &quot;waituser&quot;. If so, then the testing system will prompt before exiting
+ the test.</P>
+<H1><A NAME="36">User-Mode-Linux mysteries</A></H1>
+<UL>
+<LI> running more than one UML of the same name (e.g. &quot;west&quot;) can cause
+ problems.</LI>
+<LI> running more than one UML from the same root file system is not a
+ good idea.</LI>
+<LI> all this means that running &quot;make check&quot; twice on the same machine
+ is probably not a good idea.</LI>
+<LI> occationally, UMLs will get stuck. This can happen like:
+<!--BLOCK-->
+ 15134 ? T
+ 0:00 /spare/hugh/uml/uml2.4.18-sept5/umlbuild/east/linux (east)
+ [/bin/sh] 15138 ? T 0:00
+ /spare/hugh/uml/uml2.4.18-sept5/umlbuild/east/linux (east) [halt]</(null)>
+ these will need to be killed. Note that they are in &quot;T&quot;racing mode.</LI>
+<LI> UMLs can also hang, and will report &quot;Tracing myself and I can't get
+ out&quot;. This is a bug in UML. There are ways to find out what is going on
+ and report this to the UML people, but we don't know the magic right
+ now.</LI>
+</UL>
+<H1><A NAME="37">Getting more info from uml_netjig</A></H1>
+<P> uml_netjig can be compiled with a built-in tcpdump. This uses
+ not-yet-released code from<A HREF="http://www.tcpdump.org/">
+ www.tcpdump.org</A>. Please see the instructions in <CODE>
+testing/utils/uml_netjig/Makefile</CODE>.</P>
+<HR>
+<H1><A name="makecheck">How to configure to use &quot;make check&quot;</A></H1>
+<H2><A NAME="38_1">What is &quot;make check&quot;</A></H2>
+<P> &quot;make check&quot; is a target in the top level makefile. It takes care of
+ running a number of unit and system tests to confirm that FreeSWAN has
+ been compiled correctly, and that no new bugs have been introduced.</P>
+<P> As FreeSWAN contains both kernel and userspace components, doing
+ testing of FreeSWAN requires that the kernel be simulated. This is
+ typically difficult to do as a kernel requires that it be run on bare
+ hardware. A technology has emerged that makes this simpler. This is<A HREF="http://user-mode-linux.sourceforge.net">
+ User Mode Linux</A>.</P>
+<P> User-Mode Linux is a way to build a Linux kernel such that it can
+ run as a process under another Linux (or in the future other) kernel.
+ Presently, this can only be done for 2.4 guest kernels. The host kernel
+ can be 2.2 or 2.4.</P>
+<P> &quot;make check&quot; expects to be able to build User-Mode Linux kernels
+ with FreeSWAN included. To do this it needs to have some files
+ downloaded and extracted prior to running &quot;make check&quot;. This is
+ described in the<A HREF="umltesting.html"> UML testing</A> document.</P>
+<P> After having run the example in the UML testing document and
+ successfully brought up the four machine combination, you are ready to
+ use &quot;make check&quot;</P>
+<H2><A NAME="38_2">Running &quot;make check&quot;</A></H2>
+<P> &quot;make check&quot; works by walking the FreeSWAN source tree invoking the
+ &quot;check&quot; target at each node. At present there are tests defined only
+ for the <CODE>klips</CODE> directory. These tests will use the UML
+ infrastructure to test out pieces of the <CODE>klips</CODE> code.</P>
+<P> The results of the tests can be recorded. If the environment
+ variable <CODE>$REGRESSRESULTS</CODE> is non-null, then the results of
+ each test will be recorded. This can be used as part of a nightly
+ regression testing system, see<A HREF="nightly.html"> Nightly testing</A>
+ for more details.</P>
+<P> &quot;make check&quot; otherwise prints a minimal amount of output for each
+ test, and indicates pass/fail status of each test as they are run.
+ Failed tests do not cause failure of the target in the form of exit
+ codes.</P>
+<H1><A NAME="39">How to write a &quot;make check&quot; test</A></H1>
+<H2><A NAME="39_1">Structure of a test</A></H2>
+<P> Each test consists of a set of directories under <CODE>testing/</CODE>
+. There are directories for <CODE>klips</CODE>, <CODE>pluto</CODE>, <CODE>
+packaging</CODE> and <CODE>libraries</CODE>. Each directory has a list
+ of tests to run is stored in a file called <CODE>TESTLIST</CODE> in
+ that directory. e.g. <CODE>testing/klips/TESTLIST</CODE>.</P>
+<H2 NAME="TESTLIST"><A NAME="39_2">The TESTLIST</A></H2>
+<P> This isn't actually a shell script. It just looks like one. Some
+ tools other than /bin/sh process it. Lines that start with # are
+ comments.</P>
+<PRE>
+# test-kind     directory-containing-test       expectation     [PR#]
+</PRE>
+<P>The first word provides the test type, detailed below.</P>
+<P> The second word is the name of the test to run. This the directory
+ in which the test case is to be found..</P>
+<P>The third word may be one of:</P>
+<DL>
+<DT> blank/good</DT>
+<DD>the test is believed to function, report failure</DD>
+<DT> bad</DT>
+<DD> the test is known to fail, report unexpected success</DD>
+<DT> suspended</DT>
+<DD> the test should not be run</DD>
+</DL>
+<P> The fourth word may be a number, which is a PR# if the test is
+ failing.</P>
+<H2><A NAME="39_3">Test kinds</A></H2>
+ The test types are:
+<DL>
+<DT>skiptest</DT>
+<DD>means run no test.</DD>
+<DT>ctltest</DT>
+<DD>means run a single system without input/output.</DD>
+<DT>klipstest</DT>
+<DD>means run a single system with input/output networks</DD>
+<DT><A HREF="#umlplutotest">umlplutotest</A></DT>
+<DD>means run a pair of systems</DD>
+<DT><A HREF="#umlXhost">umlXhost</A></DT>
+<DD>run an arbitrary number of systems</DD>
+<DT>suntest (TBD)</DT>
+<DD>means run a quad of east/west/sunrise/sunset</DD>
+<DT>roadtest (TBD)</DT>
+<DD>means run a trio of east-sunrise + warrior</DD>
+<DT>extrudedtest (TBD)</DT>
+<DD>means run a quad of east-sunrise + warriorsouth + park</DD>
+<DT>mkinsttest</DT>
+<DD>a test of the &quot;make install&quot; machinery.</DD>
+<DT>kernel_test_patch</DT>
+<DD>a test of the &quot;make kernelpatch&quot; machinery.</DD>
+</DL>
+ Tests marked (TBD) have yet to be fully defined.
+<P> Each test directory has a file in it called <CODE>testparams.sh</CODE>
+. This file sets a number of environment variables to define the
+ parameters of the test.</P>
+<H2><A NAME="39_4">Common parameters</A></H2>
+<DL>
+<DT>TESTNAME</DT>
+<DD>the name of the test (repeated for checking purposes)</DD>
+<DT>TEST_TYPE</DT>
+<DD>the type of the test (repeat of type type above)</DD>
+<DT>TESTHOST</DT>
+<DD>the name of the UML machine to run for the test, typically &quot;east&quot; or
+ &quot;west&quot;</DD>
+<DT>TEST_PURPOSE</DT>
+<DD>The purpose of the test is one of:
+<DL>
+<DT>goal</DT>
+<DD>The goal purpose is where a test is defined for code that is not yet
+ finished. The test indicates when the goals have in fact been reached.</DD>
+<DT>regress</DT>
+<DD>This is a test to determine that a previously existing bug has been
+ repaired. This test will initially be created to reproduce the bug in
+ isolation, and then the bug will be fixed.</DD>
+<DT>exploit</DT>
+<DD>This is a set of packets/programs that causes a vulnerability to be
+ exposed. It is a specific variation of the regress option.</DD>
+</DL>
+</DD>
+<DT>TEST_GOAL_ITEM</DT>
+<DT></DT>
+<DD>in the case of a goal test, this is a reference to the requirements
+ document</DD>
+<DT>TEST_PROB_REPORT</DT>
+<DD>in the case of regression test, this the problem report number from
+ GNATS</DD>
+<DT>TEST_EXPLOIT_URL</DT>
+<DD>in the case of an exploit, this is a URL referencing the paper
+ explaining the origin of the test and the origin of exploit software</DD>
+<DT>REF_CONSOLE_OUTPUT</DT>
+<DD>a file in the test directory that contains the sanitized console
+ output against which to compare the output of the actual test.</DD>
+<DT>REF_CONSOLE_FIXUPS</DT>
+<DD>a list of scripts (found in <CODE>klips/test/fixups</CODE>) to apply
+ to sanitize the console output of the machine under test. These are
+ typically perl, awk or sed scripts that remove things in the kernel
+ output that change each time the test is run and/or compiled.</DD>
+<DT>INIT_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode prior to starting the tests. This file will usually
+ set up any eroute's and SADB entries that are required for the test.</P>
+<P>Lines beginning with # are skipped. Blank lines are skipped.
+ Otherwise, a shell prompted is waited for each time (consisting of <CODE>
+\n#</CODE>) and then the command is sent. Note that the prompt is waited
+ for before the command and not after, so completion of the last command
+ in the script is not required. This is often used to invoke a program
+ to monitor the system, e.g. <CODE>ipsec pf_key</CODE>.</P>
+</DD>
+<DT>RUN_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode, before the packets are sent. On single machine tests,
+ this script doesn't provide any more power than INIT_SCRIPT, but is
+ implemented for consistency's sake.</P>
+</DD>
+<DT>FINAL_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode after the final packet is sent. Similar to
+ INIT_SCRIPT, above. If not specified, then the single command &quot;halt&quot; is
+ sent. If specified, then the script should end with a halt command to
+ nicely shutdown the UML.</P>
+</DD>
+<DT>CONSOLEDIFFDEBUG</DT>
+<DD>If set to &quot;true&quot; then the series of console fixups (see
+ REF_CONSOLE_FIXUPS) will be output after it is constructed. (It should
+ be set to &quot;false&quot;, or unset otherwise)</DD>
+<DT>NETJIGDEBUG</DT>
+<DD>If set to &quot;true&quot; then the series of console fixups (see
+ REF_CONSOLE_FIXUPS) will be output after it is constructed. (It should
+ be set to &quot;false&quot;, or unset otherwise)</DD>
+<DT>NETJIGTESTDEBUG</DT>
+<DD> If set to &quot;netjig&quot;, then the results of talking to the <CODE>
+uml_netjig</CODE> will be printed to stderr during the test. In
+ addition, the jig will be invoked with --debug, which causes it to log
+ its process ID, and wait 60 seconds before continuing. This can be used
+ if you are trying to debug the <CODE>uml_netjig</CODE> program itself.</DD>
+<DT>HOSTTESTDEBUG</DT>
+<DD> If set to &quot;hosttest&quot;, then the results of taling to the consoles of
+ the UMLs will be printed to stderr during the test.</DD>
+<DT>NETJIGWAITUSER</DT>
+<DD> If set to &quot;waituser&quot;, then the scripts will wait forever for user
+ input before they shut the tests down. Use this is if you are debugging
+ through the kernel.</DD>
+<DT>PACKETRATE</DT>
+<DD> A number, in miliseconds (default is 500ms) at which packets will
+ be replayed by the netjig.</DD>
+</DL>
+<H2><A NAME="39_5">KLIPStest paramaters</A></H2>
+<P> The klipstest function starts a program (<CODE>
+testing/utils/uml_netjig/uml_netjig</CODE>) to setup a bunch of I/O
+ sockets (that simulate network interfaces). It then exports the
+ references to these sockets to the environment and invokes (using
+ system()) a given script. It waits for the script to finish.</P>
+
+<!-- <IMG SRC="single_netjig.png" ALT="block diagram of uml_netjig"> -->
+<P> The script invoked (<CODE>testing/utils/host-test.tcl</CODE>) is a
+ TCL<A HREF="http://expect.nist.gov/"> expect</A> script that arranges
+ to start the UML and configure it appropriately for the test. The
+ configuration is done with the script given above for<VAR> INIT_SCRIPT</VAR>
+. The TCL script then forks, leaves the UML in the background and exits.
+ uml_netjig continues. It then starts listening to the simulated network
+ answering ARPs and inserting packets as appropriate.</P>
+<P> The klipstest function invokes <CODE>uml_netjig</CODE> with
+ arguments to capture output from network interface(s) and insert
+ packets as appropriate:</P>
+<DL>
+<DT>PUB_INPUT</DT>
+<DD>a<A HREF="http://www.tcpdump.org/"> pcap</A> file to feed in on the
+ public (encrypted) interface. (typically, eth1)</DD>
+<DT>PRIV_INPUT</DT>
+<DD>a pcap file to feed in on the private (plain-text) interface
+ (typically, eth0).</DD>
+<DT>REF_PUB_OUTPUT</DT>
+<DD>a text file containing tcpdump output. Packets on the public (eth1)
+ interface are captured to a<A HREF="http://www.tcpdump.org/"> pcap</A>
+ file by <CODE>uml_netjig</CODE>. The klipstest function then uses
+ tcpdump on the file to produce text output, which is compared to the
+ file given.</DD>
+<DT>REF_PUB_FILTER</DT>
+<DD>a program that will filter the TCPDUMP output to do further
+ processing. Defaults to &quot;cat&quot;.</DD>
+<DT>REF_PRIV_OUTPUT</DT>
+<DD>a text file containing tcpdump output. Packets on the private (eth0)
+ interface are captured and compared after conversion by tcpdump, as
+ with<VAR> REFPUBOUTPUT</VAR>.</DD>
+<DT>REF_PRIV_FILTER</DT>
+<DD>a program that will filter the TCPDUMP output to do further
+ processing. Defaults to &quot;cat&quot;.</DD>
+<DT>EXITONEMPTY</DT>
+<DD>a flag for <CODE>uml_netjig</CODE>. It should contain
+ &quot;--exitonempty&quot; of uml_netjig should exit when all of the input (<VAR>
+PUBINPUT</VAR>,<VAR>PRIVINPUT</VAR>) packets have been injected.</DD>
+<DT>ARPREPLY</DT>
+<DD>a flag for <CODE>uml_netjig</CODE>. It should contain &quot;--arpreply&quot;
+ if <CODE>uml_netjig</CODE> should reply to ARP requests. One will
+ typically set this to avoid having to fudge the ARP cache manually.</DD>
+<DT>TCPDUMPFLAGS</DT>
+<DD>a set of flags for the tcpdump used when converting captured output.
+ Typical values will include &quot;-n&quot; to turn off DNS, and often &quot;-E&quot; to set
+ the decryption key (tcpdump 3.7.1 and higher only) for ESP packets. The
+ &quot;-t&quot; flag (turn off timestamps) is provided automatically</DD>
+<DT>NETJIG_EXTRA</DT>
+<DD>additional comments to be sent to the netjig. This may arrange to
+ record or create additional networks, or may toggle options.</DD>
+</DL>
+<H2><A NAME="39_6">mkinsttest paramaters</A></H2>
+<P> The basic concept of the <CODE>mkinsttest</CODE> test type is that
+ it performs a &quot;make install&quot; to a temporary $DESTDIR. The resulting
+ tree can then be examined to determine if it was done properly. The
+ files can be uninstalled to determine if the file list was correct, or
+ the contents of files can be examined more precisely.</P>
+<DL>
+<DT>INSTALL_FLAGS</DT>
+<DD>If set, then an install will be done. This provides the set of flags
+ to provide for the install. The target to be used (usually &quot;install&quot;)
+ must be among the flags.</DD>
+<DT>POSTINSTALL_SCRIPT</DT>
+<DD>If set, a script to run after initial &quot;make install&quot;. Two arguments
+ are provided: an absolute path to the root of the FreeSWAN src tree,
+ and an absolute path to the temporary installation area.</DD>
+<DT>INSTALL2_FLAGS</DT>
+<DD>If set, a second install will be done using these flags. Similarly
+ to INSTALL_FLAGS, the target must be among the flags.</DD>
+<DT>UNINSTALL_FLAGS</DT>
+<DD>If set, an uninstall will be done using these flags. Similarly to
+ INSTALL_FLAGS, the target (usually &quot;uninstall&quot;) must be among the
+ flags.</DD>
+<DT>REF_FIND_f_l_OUTPUT</DT>
+<DD>If set, a <CODE>find $ROOT ( -type f -or -type -l )</CODE> will be
+ done to get a list of a real files and symlinks. The resulting file
+ will be compared to the file listed by this option.</DD>
+<DT>REF_FILE_CONTENTS</DT>
+<DD>If set, it should point to a file containing records for the form:
+<PRE>
+  
+<!--VARIABLE-->
+reffile</(null)>   
+<!--VARIABLE-->
+samplefile</(null)>
+</PRE>
+ one record per line. A diff between the provided reference file, and
+ the sample file (located in the temporary installation root) will be
+ done for each record.</DD>
+</DL>
+<H2><A NAME="39_7">rpm_build_install_test paramaters</A></H2>
+<P> The <CODE>rpm_build_install_test</CODE> type is to verify that the
+ proper packing list is produced by &quot;make rpm&quot;, and that the mechanisms
+ for building the kernel modules produce consistent results.</P>
+<DL>
+<DT>RPM_KERNEL_SOURCE</DT>
+<DD>Point to an extracted copy of the RedHat kernel source code.
+ Variables from the environment may be used.</DD>
+<DT>REF_RPM_CONTENTS</DT>
+<DD>This is a file containing one record per line. Each record consists
+ of a RPM name (may contain wildcards) and a filename to compare the
+ contents to. The RPM will be located and a file list will be produced
+ with rpm2cpio.</DD>
+</DL>
+<H2><A NAME="39_8">libtest paramaters</A></H2>
+<P> The libtest test is for testing library routines. The library file
+ is expected to provided an <CODE>#ifdef</CODE> by the name of<VAR>
+ library</VAR>
+<!--CODE_MAIN</CODE-->
+. The libtest type invokes the C compiler to compile this
+ file, links it against <CODE>libfreeswan.a</CODE> (to resolve any other
+ dependancies) and runs the test with the <CODE>-r</CODE> argument to
+ invoke a regression test.</(null)></P>
+<P>The library test case is expected to do a self-test, exiting with
+ status code 0 if everything is okay, and with non-zero otherwise. A
+ core dump (exit code greater than 128) is noted specifically.</P>
+<P> Unlike other tests, there are no subdirectories required, or other
+ parameters to set.</P>
+<H2 NAME="umlplutotest"><A NAME="39_9">umlplutotest paramaters</A></H2>
+<P> The umlplutotest function starts a pair of user mode line processes.
+ This is a 2-host version of umlXhost. The &quot;EAST&quot; and &quot;WEST&quot; slots are
+ defined.</P>
+<H2 NAME="umlXhost"><A NAME="39_10">umlXhost parameters</A></H2>
+<P> The umlXtest function starts an arbitrary number of user mode line
+ processes.</P>
+
+<!-- <IMG SRC="single_netjig.png" ALT="block diagram of uml_netjig"> -->
+<P> The script invoked (<CODE>testing/utils/Xhost-test.tcl</CODE>) is a
+ TCL<A HREF="http://expect.nist.gov/"> expect</A> script that arranges
+ to start each UML and configure it appropriately for the test. It then
+ starts listening (using uml_netjig) to the simulated network answering
+ ARPs and inserting packets as appropriate.</P>
+<P> umlXtest has a series of slots, each of which should be filled by a
+ host. The list of slots is controlled by the variable, XHOST_LIST. This
+ variable should be set to a space seperated list of slots. The former
+ umlplutotest is now implemented as a variation of the umlXhost test,
+ with XHOST_LIST=&quot;EAST WEST&quot;.</P>
+<P> For each host slot that is defined, a series of variables should be
+ filled in, defining what configuration scripts to use for that host.</P>
+<P> The following are used to control the console input and output to
+ the system. Where the string ${host} is present, the host slot should
+ be filled in. I.e. for the two host system with XHOST_LIST=&quot;EAST WEST&quot;,
+ then the variables: EAST_INIT_SCRIPT and WEST_INIT_SCRIPT will exist.</P>
+<DL>
+<DT>${host}HOST</DT>
+<DD>The name of the UML host which will fill this slot</DD>
+<DT>${host}_INIT_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode prior to starting the tests. This file will usually
+ set up any eroute's and SADB entries that are required for the test.
+ Similar to INIT_SCRIPT, above.</P>
+</DD>
+<DT>${host}_RUN_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode, before the packets are sent. This set of commands is
+ run after all of the virtual machines are initialized. I.e. after
+ EAST_INIT_SCRIPT<B> AND</B> WEST_INIT_SCRIPT. This script can therefore
+ do things that require that all machines are properly configured.</P>
+</DD>
+<DT>${host}_RUN2_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode, after the packets are sent. This set of commands is
+ run before any of the virtual machines have been shut down. (I.e.
+ before EAST_FINAL_SCRIPT<B> AND</B> WEST_FINAL_SCRIPT.) This script can
+ therefore catch post-activity status reports.</P>
+</DD>
+<DT>${host}_FINAL_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode after the final packet is sent. Similar to
+ INIT_SCRIPT, above. If not specified, then the single command &quot;halt&quot; is
+ sent. Note that when this script is run, the other virtual machines may
+ already have been killed. If specified, then the script should end with
+ a halt command to nicely shutdown the UML.</P>
+</DD>
+<DT>REF_${host}_CONSOLE_OUTPUT</DT>
+<DD>Similar to REF_CONSOLE_OUTPUT, above.</DD>
+</DL>
+<P>Some additional flags apply to all hosts:</P>
+<DL>
+<DT>REF_CONSOLE_FIXUPS</DT>
+<DD>a list of scripts (found in <CODE>klips/test/fixups</CODE>) to apply
+ to sanitize the console output of the machine under test. These are
+ typically perl, awk or sed scripts that remove things in the kernel
+ output that change each time the test is run and/or compiled.</DD>
+</DL>
+<P> In addition to input to the console, the networks may have input fed
+ to them:</P>
+<DL>
+<DT>EAST_INPUT/WEST_INPUT</DT>
+<DD>a<A HREF="http://www.tcpdump.org/"> pcap</A> file to feed in on the
+ private network side of each network. The &quot;EAST&quot; and &quot;WEST&quot; here refer
+ to the networks, not the hosts.</DD>
+<DT>REF_PUB_FILTER</DT>
+<DD>a program that will filter the TCPDUMP output to do further
+ processing. Defaults to &quot;cat&quot;.</DD>
+<DT>REF_EAST_FILTER/REF_WEST_FILTER</DT>
+<DD>a program that will filter the TCPDUMP output to do further
+ processing. Defaults to &quot;cat&quot;.</DD>
+&lt;
+<DT>TCPDUMPFLAGS</DT>
+<DD>a set of flags for the tcpdump used when converting captured output.
+ Typical values will include &quot;-n&quot; to turn off DNS, and often &quot;-E&quot; to set
+ the decryption key (tcpdump 3.7.1 and higher only) for ESP packets. The
+ &quot;-t&quot; flag (turn off timestamps) is provided automatically</DD>
+<DT>REF_EAST_OUTPUT/REF_WEST_OUTPUT</DT>
+<DD>a text file containing tcpdump output. Packets on the private (eth0)
+ interface are captured and compared after conversion by tcpdump, as
+ with<VAR> REF_PUB_OUTPUT</VAR>.</DD>
+<P> There are two additional environment variables that may be set on
+ the command line:</P>
+<DL>
+<DT> NETJIGVERBOSE=verbose export NETJIGVERBOSE</DT>
+<DD> If set, then the test output will be &quot;chatty&quot;, and let you know
+ what commands it is running, and as packets are sent. Without it set,
+ the output is limited to success/failure messages.</DD>
+<DT> NETJIGTESTDEBUG=netjig export NETJIGTESTDEBUG</DT>
+<DD> This will enable debugging of the communication with uml_netjig,
+ and turn on debugging in this utility. This does not imply
+ NETJIGVERBOSE.</DD>
+</DL>
+<DT> HOSTTESTDEBUG=hosttest export HOSTTESTDEBUG</DT>
+<DD> This will show all interactions with the user-mode-linux consoles</DD>
+</DL>
+<H2 NAME="kernelpatch"><A NAME="39_11">kernel_patch_test paramaters</A></H2>
+<P> The kernel_patch_test function takes some kernel source, copies it
+ with lndir, and then applies the patch as produced by &quot;make
+ kernelpatch&quot;.</P>
+<P> The following are used to control the input and output to the
+ system:</P>
+<DL>
+<DT>KERNEL_NAME</DT>
+<DD>the kernel name, typically something like &quot;linus&quot; or &quot;rh&quot;</DD>
+<DT>KERNEL_VERSION</DT>
+<DD>the kernel version number, as in &quot;2.2&quot; or &quot;2.4&quot;.</DD>
+<DT>KERNEL_${KERNEL_NAME}${KERNEL_VERSION}_SRC</DT>
+<DD>This variable should set in the environment, probably in
+ ~/freeswan-regress-env.sh. Examples of this variables would be
+ KERNEL_LINUS2_0_SRC or KERNEL_RH7_3_SRC. This variable should point to
+ an extracted copy of the kernel source in question.</DD>
+<DT>REF_PATCH_OUTPUT</DT>
+<DD>a copy of the patch output to compare against</DD>
+<DT>KERNEL_PATCH_LEAVE_SOURCE</DT>
+<DD>If set to a non-empty string, then the patched kernel source is not
+ removed at the end of the test. This will typically be set in the
+ environment while debugging.</DD>
+</DL>
+<H2 NAME="modtest"><A NAME="39_12">module_compile paramaters</A></H2>
+<P> The module_compile test attempts to build the KLIPS module against a
+ given set of kernel source. This is also done by the RPM tests, but in
+ a very specific manner.</P>
+<P> There are two variations of this test - one where the kernel either
+ doesn't need to be configured, or is already done, and tests were there
+ is a local configuration file.</P>
+<P> Where the kernel doesn't need to be configured, the kernel source
+ that is found is simply used. It may be a RedHat-style kernel, where
+ one can cause it to configure itself via rhconfig.h-style definitions.
+ Or, it may just be a kernel tree that has been configured.</P>
+<P> If the variable KERNEL_CONFIG_FILE is set, then a new directory is
+ created for the kernel source. It is populated with lndir(1). The
+ referenced file is then copied in as .config, and &quot;make oldconfig&quot; is
+ used to configure the kernel. This resulting kernel is then used as the
+ reference source.</P>
+<P> In all cases, the kernel source is found the same was for the
+ kernelpatch test, i.e. via KERNEL_VERSION/KERNEL_NAME and
+ KERNEL_${KERNEL_NAME}${KERNEL_VERSION}_SRC.</P>
+<P> Once there is kernel source, the module is compiled using the
+ top-level &quot;make module&quot; target.</P>
+<P> The test is considered successful if an executable is found in
+ OUTPUT/module/ipsec.o at the end of the test.</P>
+<DL>
+<DT>KERNEL_NAME</DT>
+<DD>the kernel name, typically something like &quot;linus&quot; or &quot;rh&quot;</DD>
+<DT>KERNEL_VERSION</DT>
+<DD>the kernel version number, as in &quot;2.2&quot; or &quot;2.4&quot;.</DD>
+<DT>KERNEL_${KERNEL_NAME}${KERNEL_VERSION}_SRC</DT>
+<DD>This variable should set in the environment, probably in
+ ~/freeswan-regress-env.sh. Examples of this variables would be
+ KERNEL_LINUS2_0_SRC or KERNEL_RH7_3_SRC. This variable should point to
+ an extracted copy of the kernel source in question.</DD>
+<DT>KERNEL_CONFIG_FILE</DT>
+<DD>The configuration file for the kernel.</DD>
+<DT>KERNEL_PATCH_LEAVE_SOURCE</DT>
+<DD>If set to a non-empty string, then the configured kernel source is
+ not removed at the end of the test. This will typically be set in the
+ environment while debugging.</DD>
+<DT>MODULE_DEF_INCLUDE</DT>
+<DD>The include file that will be used to configure the KLIPS module,
+ and possibly the kernel source.</DD>
+</DL>
+<H1><A NAME="40">Current pitfalls</A></H1>
+<DL>
+<DT> &quot;tcpdump dissector&quot; not available.</DT>
+<DD> This is a non-fatal warning. If uml_netjig is invoked with the -t
+ option, then it will attempt to use tcpdump's dissector to decode each
+ packet that it processes. The dissector is presently not available, so
+ this option it normally turned off at compile time. The dissector
+ library will be released with tcpdump version 4.0.</DD>
+</DL>
+<HR>
+<H1><A name="nightly">Nightly regression testing</A></H1>
+<P> The nightly regression testing system consists of several shell
+ scripts and some perl scripts. The goal is to check out a fresh tree,
+ run &quot;make check&quot; on it, record the results and summarize the results to
+ the team and to the web site.</P>
+<P> Output can be found on<A HREF="http://bugs.freeswan.org:81/"> adams</A>
+, although the tests are actually run on another project machine.</P>
+<H1><A name="nightlyhowto">How to setup the nightly build</A></H1>
+<P> The best way to do nightly testing is to setup a new account. We
+ call the account &quot;build&quot; - you could call it something else, but there
+ may still be some references to ~build in the scripts.</P>
+<H2><A NAME="42_1"> Files you need to know about</A></H2>
+<P> As few files as possible need to be extracted from the source tree -
+ files are run from the source tree whenever possible. However, there
+ are some bootstrap and configuration files that are necessary.</P>
+<P> There are 7 files in testing/utils that are involved:</P>
+<DL>
+<DT> nightly-sample.sh</DT>
+<DD> This is the root of the build process. This file should be copied
+ out of the CVS tree, to $HOME/bin/nightly.sh of the build account. This
+ file should be invoked from cron.</DD>
+<DT> freeswan-regress-env-sample.sh</DT>
+<DD> This file should be copied to $HOME/freeswan-regress-env.sh. It
+ should be edited to localize the values. See below.</DD>
+<DT> regress-cleanup.pl</DT>
+<DD> This file needs to be copied to $HOME/bin/regress-cleanup.pl. It is
+ invoked by the nightly file before doing anything else. It removes
+ previous nights builds in order to free up disk space for the build
+ about to be done.</DD>
+<DT> teammail-sample.sh</DT>
+<DD> A script used to send results email to the &quot;team&quot;. This sample
+ script could be copied to $HOME/bin/teammail.sh. This version will PGP
+ encrypt all the output to the team members. If this script is used,
+ then PGP will have to be properly setup to have the right keys.</DD>
+<DT> regress-nightly.sh</DT>
+<DD> This is the first stage of the nightly build. This stage will call
+ other scripts as appropriate, and will extract the source code from
+ CVS. This script should be copied to $HOME/bin/regress-nightly.sh</DD>
+<DT> regress-stage2.sh</DT>
+<DD> This is the second stage of the nightly build. It is called in
+ place. It essentially sets up the UML setup in umlsetup.sh, and calls
+ &quot;make check&quot;.</DD>
+<DT> regress-summarize-results.pl</DT>
+<DD> This script will summarize the results from the tests to a
+ permanent directory set by $REGRESSRESULTS. It is invoked from the
+ stage2 nightly script.</DD>
+<DT> regress-chart.sh</DT>
+<DD> This script is called at the end of the build process, and will
+ summarize each night's results (as saved into $REGRESSRESULTS by
+ regress-summarize-results.pl) as a chart using gnuplot. Note that this
+ requires at least gnuplot 3.7.2.</DD>
+</DL>
+<H2><A NAME="42_2">Configuring freeswan-regress-env.sh</A></H2>
+<P>For more info on KERNPOOL, UMLPATCH, BASICROOT and SHAREDIR, see<A HREF="umltesting.html">
+ User-Mode-Linux testing guide</A>.</P>
+<DL>
+<DT> KERNPOOL</DT>
+<DD> Extract copy of some kernel source to be used for UML builds</DD>
+<DT> UMLPATCH</DT>
+<DD> matching User-Mode-Linux patch.</DD>
+<DT> BASICROOT</DT>
+<DD> the root file system image (see<A HREF="umltesting.html">
+ User-Mode-Linux testing guide</A>).</DD>
+<DT> SHAREDIR=${BASICROOT}/usr/share</DT>
+<DD> The /usr/share to use.</DD>
+<DT> REGRESSTREE</DT>
+<DD> A directory in which to store the nightly regression results.
+ Directories will be created by date in this tree.</DD>
+<DT> TCPDUMP=tcpdump-3.7.1</DT>
+<DD> The path to the<A HREF="http://www.tcpdump.org/"> tcpdump</A> to
+ use. This must have crypto compiled in, and must be at least 3.7.1</DD>
+<DT> KERNEL_RH7_2_SRC=/a3/kernel_sources/linux-2.4.9-13/</DT>
+<DD> An extracted copy of the RedHat 7.2. kernel source. If set, then
+ the packaging/rpm-rh72-install-01 test will be run, and an RPM will be
+ built as a test.</DD>
+<DT> KERNEL_RH7_3_SRC=/a3/kernel_sources/rh/linux-2.4.18-5</DT>
+<DD> An extracted copy of the RedHat 7.3. kernel source. If set, then
+ the packaging/rpm-rh73-install-01 test will be run, and an RPM will be
+ built as a test.</DD>
+<DT> NIGHTLY_WATCHERS=&quot;userid,userid,userid&quot;</DT>
+<DD> The list of people who should receive nightly output. This is used
+ by teammail.sh</DD>
+<DT> FAILLINES=128</DT>
+<DD> How many lines of failed test output to include in the nightly
+ output</DD>
+<DT> PATH=$PATH:/sandel/bin export PATH</DT>
+<DD> You can also override the path if necessary here.</DD>
+<DT> CVSROOT=:pserver:anoncvs@ip212.xs4net.freeswan.org:/freeswan/MASTER</DT>
+<DD> The CVSROOT to use. This example may work for anonymous CVS, but
+ will be 12 hours behind the primary, and is still experimental</DD>
+<DT> SNAPSHOTSIGDIR=$HOME/snapshot-sig</DT>
+<DD> For the release tools, where to put the generated per-snapshot
+ signature keys</DD>
+<DT> LASTREL=1.97</DT>
+<DD> the name of the last release branch (to find the right per-snapshot
+ signature</DD>
+<DD></DD>
+</DL>
+</BODY>
+</HTML>
diff --git a/doc/Makefile b/doc/Makefile
new file mode 100644
index 000000000..f8209b3a8
--- /dev/null
+++ b/doc/Makefile
@@ -0,0 +1,167 @@
+# Makefile to generate various formats from HTML source
+#
+# Assumes the htmldoc utility is available.
+# This can be downloaded from www.easysw.com
+#
+# Also needs lynx(1) for HTML-to-text conversion
+
+.SUFFIXES: .png .fig
+
+FREESWANSRCDIR=..
+include ${FREESWANSRCDIR}/Makefile.inc
+
+# Format arguments for htmldoc
+F="--toclevels 4 --header 1cd"
+
+# source files in subdirectory
+# basic stuff
+a=src/intro.html src/upgrading.html src/quickstart.html \
+  src/policygroups.html src/faq.html
+
+# related
+b=src/manpages.html src/firewall.html src/trouble.html
+
+# more advanced
+c=src/compat.html src/interop.html src/performance.html \
+	src/testing.html src/kernel.html src/adv_config.html \
+	src/install.html src/config.html \
+	src/background.html src/user_examples.html \
+	src/makecheck.html src/umltesting.html \
+
+# background and reference material
+d=src/politics.html src/ipsec.html \
+	src/mail.html src/web.html src/glossary.html src/biblio.html \
+	src/rfc.html src/roadmap.html
+
+# build and release related
+e=src/umltesting.html src/makecheck.html src/nightly.html
+
+sections=$a $b $c $d $e
+
+# separate HTML files built in current directory
+separate=intro.html install.html config.html manpages.html \
+	firewall.html trouble.html kernel.html roadmap.html \
+	compat.html interop.html politics.html ipsec.html \
+	mail.html performance.html testing.html web.html \
+	glossary.html biblio.html rfc.html faq.html \
+	adv_config.html user_examples.html background.html \
+	quickstart.html umltesting.html makecheck.html nightly.html \
+        upgrading.html policygroups.html
+
+# various one-big-file formats
+howto=HowTo.html HowTo.ps HowTo.pdf HowTo.txt
+
+alldocs=${seperate} ${howto} index.html toc.html
+
+srcdir=..
+# where are scripts
+SCRIPTDIR=utils
+
+# where
+TESTINGDIR=${srcdir}/testing
+
+# where do we put HTML manpages?
+HMANDIR=manpage.d
+
+# default, build HTML only
+# dependencies build most of it
+# then we add index
+index.html: toc.html HowTo.html manpages src/index.html
+	cp src/index.html index.html
+
+# separate files plus table of contents
+# and then remove HTML formatting added by htmldoc
+toc.html : $(sections)
+	@htmldoc -t html --path ".;${TESTINGDIR}/doc" -d .  $(sections)
+	@$(SCRIPTDIR)/cleanhtml.sh $(SCRIPTDIR)/cleanhtml.sed $(separate)
+
+# one big HTML file
+HowTo.html : $(sections)
+	@htmldoc -t html --toclevels 4 --header ' cf' -f $@ $(sections)
+
+# other HowTo formats
+HowTo.txt: HowTo.html
+	lynx -dump $< > $@
+
+HowTo.ps : $(sections)
+	htmldoc -f $@ $(sections)
+
+HowTo.pdf : $(sections)
+	@htmldoc -f $@ $(sections)
+
+manpages:	manp
+
+manp:	$(SCRIPTDIR)/mkhtmlman
+	@$(SCRIPTDIR)/mkhtmlman $(HMANDIR) `find ../programs ../lib ../linux -type f -name '*.[1-8]' -print | grep -v lwres | grep -v CVS`
+
+programs: 
+
+all: #$(howto) $(manpages) index.html
+
+clean:
+	@rm -f $(howto) $(separate) toc.html index.html
+	@rm -rf $(HMANDIR)
+
+install:
+#install: ${alldocs} manpages
+#	@mkdir -p ${DOCDIR}
+#	@$(foreach f, $(alldocs), \
+#		$(INSTALL) $f ${DOCDIR} || exit 1;\
+#	)
+#	@find ${HMANDIR} -type f -name "*.html" -print | while read file; \
+#	do \
+#		$(INSTALL) $$file ${DOCDIR} || exit 1;\
+#	done;
+
+install_file_list:
+	@$(foreach f, $(alldocs), \
+		echo ${DOCDIR}/$f; \
+	)
+	@if [ -d ${HMANDIR} ]; then find ${HMANDIR} -type f -name "*.html" -print | while read file; \
+	do \
+		echo ${DOCDIR}/$$file; \
+	done; fi;
+
+checkprograms: ;
+
+check: ;
+
+# not enabled by default, because xml2rfc must be installed first.
+drafts: draft-richardson-ipsec-opportunistic.txt src/draft-richardson-ipsec-opportunistic.html \
+	draft-richardson-ipsec-rr.txt src/draft-richardson-ipsec-rr.html
+
+draft-richardson-ipsec-opportunistic.txt: src/draft-richardson-ipsec-opportunistic.xml
+	XML_LIBRARY=$(XML_LIBRARY):./src xml2rfc xml2rfc $? $@
+
+draft-richardson-ipsec-rr.txt: src/draft-richardson-ipsec-rr.xml
+	XML_LIBRARY=$(XML_LIBRARY):./src xml2rfc xml2rfc $? $@
+
+draft-%.nr: src/draft-%.xml
+	XML_LIBRARY=$(XML_LIBRARY):./src xml2rfc xml2nroff $? $@
+
+draft-%.html: draft-%.xml
+	XML_LIBRARY=$(XML_LIBRARY):./src xml2rfc xml2html $? $@
+
+
+.fig.eps: 
+	fig2dev -L ps $< $@
+
+.fig.png: 
+	fig2dev -L png $< $@
+
+single_netjig.png: testing/single_netjig.fig
+multi_netjig.png: testing/multi_netjig.fig
+
+makecheck.html: single_netjig.png multi_netjig.png
+
+#
+# DocBook based documentation
+#
+xmldocs: mast.html klips/mast.4
+	
+mast.html: klips/mast.xml
+	xmlto html klips/mast.xml
+
+klips/mast.4: klips/mast.xml
+	xmlto -o klips man klips/mast.xml
+
diff --git a/doc/README b/doc/README
new file mode 100644
index 000000000..ff5564e4e
--- /dev/null
+++ b/doc/README
@@ -0,0 +1,39 @@
+This directory has the HTML FreeS/WAN documentation.
+
+Start from either of:
+
+	toc.html	table of contents for HTML docs
+	index.html	pointers to everything, including
+			 text files not in HTML docs
+
+The Makefile in this directory can generate various
+things from the HTML source:
+
+	./*.html	individual HTML files
+			with previous/contents/next links
+	toc.html	table of contents
+	HowTo.html	one big HTML file
+	HowTo.ps	Postscript
+	HowTo.pdf	PDF
+	HowTo.txt	ASCII text
+
+Not all of the above are in the shipped version. All but
+text are on our website, www.freeswan.org. To get PDF or
+Postscript, either grab them from the web or install
+htmldoc from www.easysw.com, then use the Makefile.
+
+Subdirectories are:
+	src/*.html		HTML source files
+	manpage.d/*.html	HTML versions of man pages
+
+You should not need to look at these, except for following
+links to HTML man pages.
+
+The Internet Drafts are natively in XML format. They have been 
+converted with Marshall Rose's xml2rfc.
+
+xml2rfc is available at xml.resource.org. 
+You may have to install the TclXML package by symlinking it into
+/usr/lib/tcl8.3 or some such.  
+
+
diff --git a/doc/adv_config.html b/doc/adv_config.html
new file mode 100644
index 000000000..4b779c753
--- /dev/null
+++ b/doc/adv_config.html
@@ -0,0 +1,1232 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
+H5 { font-family: sans-serif }
+H6 { font-family: sans-serif }
+SUB { font-size: smaller }
+SUP { font-size: smaller }
+PRE { font-family: monospace }
+--></STYLE>
+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="kernel.html">Previous</A>
+<A HREF="install.html">Next</A>
+<HR>
+<H1><A name="adv_config">Other configuration possibilities</A></H1>
+<P>This document describes various options for FreeS/WAN configuration
+ which are less used or more complex (often both) than the standard
+ cases described in our<A href="config.html#config"> config</A> and<A href="quickstart.html#quick_guide">
+ quickstart</A> documents.</P>
+<H2><A name="thumb">Some rules of thumb about configuration</A></H2>
+<H3><A name="cheap.tunnel">Tunnels are cheap</A></H3>
+<P>Nearly all of the overhead in IPsec processing is in the encryption
+ and authentication of packets. Our<A href="performance.html">
+ performance</A> document discusses these overheads.</P>
+<P>Beside those overheads, the cost of managing additional tunnels is
+ trivial. Whether your gateway supports one tunnel or ten just does not
+ matter. A hundred might be a problem; there is a<A href="performance.html#biggate">
+ section</A> on this in the performance document.</P>
+<P>So, in nearly all cases, if using multiple tunnels gives you a
+ reasonable way to describe what you need to do, you should describe it
+ that way in your configuration files.</P>
+<P>For example, one user recently asked on a mailing list about this
+ network configuration:</P>
+<PRE>        netA---gwA---gwB---netB
+                            |----netC
+
+   netA and B are secured netC not.
+   netA and gwA can not access netC</PRE>
+<P>The user had constructed only one tunnel, netA to netB, and wanted to
+ know how to use ip-route to get netC packets into it. This is entirely
+ unnecessary. One of the replies was:</P>
+<PRE>  The simplest way and indeed the right way to
+  solve this problem is to set up two connections:
+
+        leftsubnet=NetA
+        left=gwA
+        right=gwB
+        rightsubnet=NetB
+  and
+        leftsubnet=NetA
+        left=gwA
+        right=gwB
+        rightsubnet=NetC</PRE>
+<P>This would still be correct even if we added nets D, E, F, ... to the
+ above diagram and needed twenty tunnels.</P>
+<P>Of course another possibility would be to just use one tunnel, with a
+ subnet mask that includes both netB and netC (or B, C, D, ...). See
+ next section.</P>
+<P>In general, you can construct as many tunnels as you need. Networks
+ like netC in this example that do not connect directly to the gateway
+ are fine, as long as the gateway can route to them.</P>
+<P>The number of tunnels can become an issue if it reaches 50 or so.
+ This is discussed in the<A href="performance.html#biggate"> performance</A>
+ document. Look there for information on supporting hundreds of Road
+ Warriors from one gateway.</P>
+<P>If you find yourself with too many tunnels for some reason like
+ having eight subnets at one location and nine at another so you end up
+ with 9*8=72 tunnels, read the next section here.</P>
+<H3><A name="subnet.size">Subnet sizes</A></H3>
+<P>The subnets used in<VAR> leftsubnet</VAR> and<VAR> rightsubnet</VAR>
+ can be of any size that fits your needs, and they need not correspond
+ to physical networks.</P>
+<P>You adjust the size by changing the<A href="glossary.html#subnet">
+ subnet mask</A>, the number after the slash in the subnet description.
+ For example</P>
+<UL>
+<LI>in 192.168.100.0/24 the /24 mask says 24 bits are used to designate
+ the network. This leave 8 bits to label machines. This subnet has 256
+ addresses. .0 and .255 are reserved, so it can have 254 machines.</LI>
+<LI>A subnet with a /23 mask would be twice as large, 512 addresses.</LI>
+<LI>A subnet with a /25 mask would be half the size, 128 addresses.</LI>
+<LI>/0 is the whole Internet</LI>
+<LI>/32 is a single machine</LI>
+</UL>
+<P>As an example of using these in connection descriptions, suppose your
+ company's head office has four physical networks using the address
+ ranges:</P>
+<DL>
+<DT>192.168.100.0/24</DT>
+<DD>development</DD>
+<DT>192.168.101.0/24</DT>
+<DD>production</DD>
+<DT>192.168.102.0/24</DT>
+<DD>marketing</DD>
+<DT>192.168.103.0/24</DT>
+<DD>administration</DD>
+</DL>
+<P>You can use exactly those subnets in your connection descriptions, or
+ use larger subnets to grant broad access if required:</P>
+<DL>
+<DT>leftsubnet=192.168.100.0/24</DT>
+<DD>remote hosts can access only development</DD>
+<DT>leftsubnet=192.168.100.0/23</DT>
+<DD>remote hosts can access development or production</DD>
+<DT>leftsubnet=192.168.102.0/23</DT>
+<DD>remote hosts can access marketing or administration</DD>
+<DT>leftsubnet=192.168.100.0/22</DT>
+<DD>remote hosts can access any of the four departments</DD>
+</DL>
+<P>or use smaller subnets to restrict access:</P>
+<DL>
+<DT>leftsubnet=192.168.103.0/24</DT>
+<DD>remote hosts can access any machine in administration</DD>
+<DT>leftsubnet=192.168.103.64/28</DT>
+<DD>remote hosts can access only certain machines in administration.</DD>
+<DT>leftsubnet=192.168.103.42/32</DT>
+<DD>remote hosts can access only one particular machine in
+ administration</DD>
+</DL>
+<P>To be exact, 192.68.103.64/28 means all addresses whose top 28 bits
+ match 192.168.103.64. There are 16 of these because there are 16
+ possibilities for the remainingg 4 bits. Their addresses are
+ 192.168.103.64 to 192.168.103.79.</P>
+<P>Each connection description can use a different subnet if required.</P>
+<P>It is possible to use all the examples above on the same FreeS/WAN
+ gateway, each in a different connection description, perhaps for
+ different classes of user or for different remote offices.</P>
+<P>It is also possible to have multiple tunnels using different<VAR>
+ leftsubnet</VAR> descriptions with the same<VAR> right</VAR>. For
+ example, when the marketing manager is on the road he or she might have
+ access to:</P>
+<DL>
+<DT>leftsubnet=192.168.102.0/24</DT>
+<DD>all machines in marketing</DD>
+<DT>192.168.101.32/29</DT>
+<DD>some machines in production</DD>
+<DT>leftsubnet=192.168.103.42/32</DT>
+<DD>one particular machine in administration</DD>
+</DL>
+<P>This takes three tunnels, but tunnels are cheap. If the laptop is set
+ up to build all three tunnels automatically, then he or she can access
+ all these machines concurrently, perhaps from different windows.</P>
+<H3><A name="example.more">Other network layouts</A></H3>
+<P>Here is the usual network picture for a site-to-site VPN::</P>
+<PRE>     Sunset==========West------------------East=========Sunrise
+           local net       untrusted net       local net</PRE>
+<P>and for the Road Warrior::</P>
+<PRE>                                           telecommuter's PC or
+                                           traveller's laptop
+     Sunset==========West------------------East
+         corporate LAN     untrusted net</PRE>
+<P>Other configurations are also possible.</P>
+<H4><A name="internet.subnet">The Internet as a big subnet</A></H4>
+<P>A telecommuter might have:</P>
+<PRE>     Sunset==========West------------------East ================= firewall --- the Internet
+         home network      untrusted net        corporate network</PRE>
+<P>This can be described as a special case of the general
+ subnet-to-subnet connection. The subnet on the right is 0.0.0.0/0, the
+ whole Internet.</P>
+<P>West (the home gateway) can have its firewall rules set up so that
+ only IPsec packets to East are allowed out. It will then behave as if
+ its only connection to the world was a wire to East.</P>
+<P>When machines on the home network need to reach the Internet, they do
+ so via the tunnel, East and the corporate firewall. From the viewpoint
+ of the Internet (perhaps of some EvilDoer trying to break in!), those
+ home office machines are behind the firewall and protected by it.</P>
+<H4><A name="wireless.config">Wireless</A></H4>
+<P>Another possible configuration comes up when you do not trust the
+ local network, either because you have very high security standards or
+ because your are using easily-intercepted wireless signals.</P>
+<P>Some wireless networks have built-in encryption called<A href="glossary.html#WEP">
+ WEP</A>, but its security is dubious. It is a fairly common practice to
+ use IPsec instead.</P>
+<P>In this case, part of your network may look like this:</P>
+<PRE>          West-----------------------------East == the rest of your network
+     workstation   untrusted wireless net</PRE>
+<P>Of course, there would likely be several wireless workstations, each
+ with its own IPsec tunnel to the East gateway.</P>
+<P>The connection descriptions look much like Road Warrior descriptions:</P>
+<UL>
+<LI>each workstation should have its own unique
+<UL>
+<LI>identifier for IPsec</LI>
+<LI>RSA key</LI>
+<LI>connection description.</LI>
+</UL>
+</LI>
+<LI>on the gateway, use<VAR> left=%any</VAR>, or the workstation IP
+ address</LI>
+<LI>on workstations,<VAR> left=%defaultroute</VAR>, or the workstation
+ IP address</LI>
+<LI><VAR>leftsubnet=</VAR> is not used.</LI>
+</UL>
+<P>The<VAR> rightsubnet=</VAR> parameter might be set in any of several
+ ways:</P>
+<DL>
+<DT>rightsubnet=0.0.0.0/0</DT>
+<DD>allowing workstations to access the entire Internet (see<A href="#internet.subnet">
+ above</A>)</DD>
+<DT>rightsubnet=a.b.c.0/24</DT>
+<DD>allowing access to your entire local network</DD>
+<DT>rightsubnet=a.b.c.d/32</DT>
+<DD>restricting the workstation to connecting to a particular server</DD>
+</DL>
+<P>Of course you can mix and match these as required. For example, a
+ university might allow faculty full Internet access while letting
+ student laptops connect only to a group of lab machines.</P>
+<H2><A name="choose">Choosing connection types</A></H2>
+<P>One choice you need to make before configuring additional connections
+ is what type or types of connections you will use. There are several
+ options, and you can use more than one concurrently.</P>
+<H3><A name="man-auto">Manual vs. automatic keying</A></H3>
+<P>IPsec allows two types of connections, with manual or automatic
+ keying. FreeS/WAN starts them with commands such as:</P>
+<PRE>        ipsec manual --up <VAR>name</VAR>
+        ipsec auto --up <VAR>name</VAR></PRE>
+<P>The difference is in how they are keyed.</P>
+<DL>
+<DT><A href="glossary.html#manual">Manually keyed</A> connections</DT>
+<DD>use keys stored in<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf</A>
+.</DD>
+<DT><A href="glossary.html#auto">Automatically keyed</A> connections</DT>
+<DD>use keys automatically generated by the Pluto key negotiation
+ daemon. The key negotiation protocol,<A href="glossary.html#IKE"> IKE</A>
+, must authenticate the other system. (It is vulnerable to a<A href="glossary.html#middle">
+ man-in-the-middle attack</A> if used without authentication.) We
+ currently support two authentication methods:
+<UL>
+<LI>using shared secrets stored in<A href="manpage.d/ipsec.secrets.5.html">
+ ipsec.secrets</A>.</LI>
+<LI>RSA<A href="glossary.html#public"> public key</A> authentication,
+ with our machine's private key in<A href="manpage.d/ipsec.secrets.5.html">
+ ipsec.secrets</A>. Public keys for other machines may either be placed
+ in<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf</A> or provided via
+ DNS.</LI>
+</UL>
+<P>A third method, using RSA keys embedded in<A href="glossary.html#X509">
+ X.509</A> certtificates, is provided by user<A href="web.html#patch">
+ patches</A>.</P>
+</DD>
+</DL>
+<P><A href="glossary.html#manual">Manually keyed</A> connections provide
+ weaker security than<A href="glossary.html#auto"> automatically keyed</A>
+ connections. An opponent who reads ipsec.secrets(5) gets your
+ encryption key and can read all data encrypted by it. If he or she has
+ an archive of old messages, all of them back to your last key change
+ are also readable.</P>
+<P>With automatically-(re)-keyed connections, an opponent who reads
+ ipsec.secrets(5) gets the key used to authenticate your system in IKE
+ -- the shared secret or your private key, depending what authentication
+ mechanism is in use. However, he or she does not automatically gain
+ access to any encryption keys or any data.</P>
+<P>An attacker who has your authentication key can mount a<A href="glossary.html#middle">
+ man-in-the-middle attack</A> and, if that succeeds, he or she will get
+ encryption keys and data. This is a serious danger, but it is better
+ than having the attacker read everyting as soon as he or she breaks
+ into ipsec.secrets(5).. Moreover, the keys change often so an opponent
+ who gets one key does not get a large amount of data. To read all your
+ data, he or she would have to do a man-in-the-middle attack at every
+ key change.</P>
+<P>We discuss using<A href="#prodman"> manual keying in production</A>
+ below, but this is<STRONG> not recommended</STRONG> except in special
+ circumstances, such as needing to communicate with some implementation
+ that offers no auto-keyed mode compatible with FreeS/WAN.</P>
+<P>Manual keying may also be useful for testing. There is some
+ discussion of this in our<A href="faq.html#man4debug"> FAQ</A>.</P>
+<H3><A name="auto-auth">Authentication methods for auto-keying</A></H3>
+<P>The IKE protocol which Pluto uses to negotiate connections between
+ gateways must use some form of authentication of peers. A gateway must
+ know who it is talking to before it can create a secure connection. We
+ support two basic methods for this authentication:</P>
+<UL>
+<LI>shared secrets, stored in<A href="manpage.d/ipsec.secrets.5.html">
+ ipsec.secrets(5)</A></LI>
+<LI>RSA authentication</LI>
+</UL>
+<P>There are, howver, several variations on the RSA theme, using
+ different methods of managing the RSA keys:</P>
+<UL>
+<LI>our RSA private key in<A href="manpage.d/ipsec.secrets.5.html">
+ ipsec.secrets(5)</A> with other gateways' public keys
+<DL>
+<DT>either</DT>
+<DD>stored in<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf(5)</A></DD>
+<DT>or</DT>
+<DD>looked up via<A href="glossary.html#DNS"> DNS</A></DD>
+</DL>
+</LI>
+<LI>authentication with<A href="glossary.html#x509"> x.509</A>
+ certificates.; See our<A href="web.html#patch"> links section</A> for
+ information on user-contributed patches for this.:</LI>
+</UL>
+<P>Public keys in<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf(5</A>
+) give a reasonably straightforward method of specifying keys for
+ explicitly configured connections.</P>
+<P>Putting public keys in DNS allows us to support<A href="glossary.html#carpediem">
+ opportunistic encryption</A>. Any two FreeS/WAN gateways can provide
+ secure communication, without either of them having any preset
+ information about the other.</P>
+<P>X.509 certificates may be required to interface to various<A href="glossary.html#PKI">
+ PKI</A>s.</P>
+<H3><A name="adv-pk">Advantages of public key methods</A></H3>
+<P>Authentication with a<A href="glossary.html#public"> public key</A>
+ method such as<A href="glossary.html#RSA"> RSA</A> has some important
+ advantages over using shared secrets.</P>
+<UL>
+<LI>no problem of secure transmission of secrets
+<UL>
+<LI>A shared secret must be shared, so you have the problem of
+ transmitting it securely to the other party. If you get this wrong, you
+ have no security.</LI>
+<LI>With a public key technique, you transmit only your public key. The
+ system is designed to ensure that it does not matter if an enemy
+ obtains public keys. The private key never leaves your machine.</LI>
+</UL>
+</LI>
+<LI>easier management
+<UL>
+<LI>Suppose you have 20 branch offices all connecting to one gateway at
+ head office, and all using shared secrets. Then the head office admin
+ has 20 secrets to manage. Each of them must be kept secret not only
+ from outsiders, but also from 19 of the branch office admins. The
+ branch office admins have only one secret each to manage.
+<P>If the branch offices need to talk to each other, this becomes
+ problematic. You need another 20*19/2 = 190 secrets for
+ branch-to-branch communication, each known to exactly two branches. Now
+ all the branch admins have the headache of handling 20 keys, each
+ shared with exactly one other branch or with head office.</P>
+<P>For larger numbers of branches, the number of connections and secrets
+ increases quadratically and managing them becomes a nightmare. A
+ 1000-gateway fully connected network needs 499,500 secrets, each known
+ to exactly two players. There are ways to reduce this problem, for
+ example by introducing a central key server, but these involve
+ additional communication overheads, more administrative work, and new
+ threats that must be carefully guarded against.</P>
+</LI>
+<LI>With public key techniques, the<EM> only</EM> thing you have to keep
+ secret is your private key, and<EM> you keep that secret from everyone</EM>
+.
+<P>As network size increaes, the number of public keys used increases
+ linearly with the number of nodes. This still requires careful
+ administration in large applications, but is nothing like the disaster
+ of a quadratic increase. On a 1000-gateway network, you have 1000
+ private keys, each of which must be kept secure on one machine, and
+ 1000 public keys which must be distributed. This is not a trivial
+ problem, but it is manageable.</P>
+</LI>
+</UL>
+</LI>
+<LI>does not require fixed IP addresses
+<UL>
+<LI>When shared secrets are used in IPsec, the responder must be able to
+ tell which secret to use by looking at the IP address on the incoming
+ packets. When the other parties do not have a fixed IP address to be
+ identified by (for example, on nearly all dialup ISP connections and
+ many cable or ADSL links), this does not work well -- all must share
+ the same secret!</LI>
+<LI>When RSA authentication is in use, the initiator can identify itself
+ by name before the key must be determined. The responder then checks
+ that the message is signed with the public key corresponding to that
+ name.</LI>
+</UL>
+</LI>
+</UL>
+<P>There is also a disadvantage:</P>
+<UL>
+<LI>your private key is a single point of attack, extremely valuable to
+ an enemy
+<UL>
+<LI>with shared secrets, an attacker who steals your ipsec.secrets file
+ can impersonate you or try<A href="glossary.html#middle">
+ man-in-the-middle</A> attacks, but can only attack connections
+ described in that file</LI>
+<LI>an attacker who steals your private key gains the chance to attack
+ not only existing connections<EM> but also any future connections</EM>
+ created using that key</LI>
+</UL>
+</LI>
+</UL>
+<P>This is partly counterbalanced by the fact that the key is never
+ transmitted and remains under your control at all times. It is likely
+ necessary, however, to take account of this in setting security policy.
+ For example, you should change gateway keys when an administrator
+ leaves the company, and should change them periodically in any case.</P>
+<P>Overall, public key methods are<STRONG> more secure, more easily
+ managed and more flexible</STRONG>. We recommend that they be used for
+ all connections, unless there is a compelling reason to do otherwise.</P>
+<H2><A name="prodsecrets">Using shared secrets in production</A></H2>
+<P>Generally, public key methods are preferred for reasons given above,
+ but shared secrets can be used with no loss of security, just more work
+ and perhaps more need to take precautions.</P>
+<P>What I call &quot;shared secrets&quot; are sometimes also called &quot;pre-shared
+ keys&quot;. They are used only for for authentication, never for encryption.
+ Calling them &quot;pre-shared keys&quot; has confused some users into thinking
+ they were encryption keys, so I prefer to avoid the term..</P>
+<P>If you are interoperating with another IPsec implementation, you may
+ find its documentation calling them &quot;passphrases&quot;.</P>
+<H3><A name="secrets">Putting secrets in ipsec.secrets(5)</A></H3>
+<P>If shared secrets are to be used to<A href="glossary.html#authentication">
+ authenticate</A> communication for the<A href="glossary.html#DH">
+ Diffie-Hellman</A> key exchange in the<A href="glossary.html#IKE"> IKE</A>
+ protocol, then those secrets must be stored in<VAR> /etc/ipsec.secrets</VAR>
+. For details, see the<A href="manpage.d/ipsec.secrets.5.html">
+ ipsec.secrets(5)</A> man page.</P>
+<P>A few considerations are vital:</P>
+<UL>
+<LI>make the secrets long and unguessable. Since they need not be
+ remembered by humans, very long ugly strings may be used. We suggest
+ using our<A href="manpage.d/ipsec_ranbits.8.html"> ipsec_ranbits(8)</A>
+ utility to generate long (128 bits or more) random strings.</LI>
+<LI>transmit secrets securely. You have to share them with other
+ systems, but you lose if they are intercepted and used against you. Use<A
+href="glossary.html#PGP"> PGP</A>,<A href="glossary.html#SSH"> SSH</A>,
+ hand delivery of a floppy disk which is then destroyed, or some other
+ trustworthy method to deliver them.</LI>
+<LI>store secrets securely, in root-owned files with permissions
+ rw------.</LI>
+<LI>limit sharing of secrets. Alice, Bob, Carol and Dave may all talk to
+ each other, but only Alice and Bob should know the secret for an
+ Alice-Bob link.</LI>
+<LI><STRONG>do not share private keys</STRONG>. The private key for RSA
+ authentication of your system is stored in<A href="manpage.d/ipsec.secrets.5.html">
+ ipsec.secrets(5)</A>, but it is a different class of secret from the
+ pre-shared keys used for the &quot;shared secret&quot; authentication. No-one but
+ you should have the RSA private key.</LI>
+</UL>
+<P>Each line has the IP addresses of the two gateways plus the secret.
+ It should look something like this:</P>
+<PRE>        10.0.0.1 11.0.0.1 : PSK &quot;jxTR1lnmSjuj33n4W51uW3kTR55luUmSmnlRUuWnkjRj3UuTV4T3USSu23Uk55nWu5TkTUnjT&quot;</PRE>
+<P><VAR>PSK</VAR> indicates the use of a<STRONG> p</STRONG>re-<STRONG>s</STRONG>
+hared<STRONG> k</STRONG>ey. The quotes and the whitespace shown are
+ required.</P>
+<P>You can use any character string as your secret. For security, it
+ should be both long and extremely hard to guess. We provide a utility
+ to generate such strings,<A href="manpage.d/ipsec_ranbits.8.html">
+ ipsec_ranbits(8)</A>.</P>
+<P>You want the same secret on the two gateways used, so you create a
+ line with that secret and the two gateway IP addresses. The
+ installation process supplies an example secret, useful<EM> only</EM>
+ for testing. You must change it for production use.</P>
+<H3><A name="securing.secrets">File security</A></H3>
+<P>You must deliver this file, or the relevant part of it, to the other
+ gateway machine by some<STRONG> secure</STRONG> means.<EM> Don't just
+ FTP or mail the file!</EM> It is vital that the secrets in it remain
+ secret. An attacker who knew those could easily have<EM> all the data
+ on your &quot;secure&quot; connection</EM>.</P>
+<P>This file must be owned by root and should have permissions<VAR>
+ rw-------</VAR>.</P>
+<H3><A name="notroadshared">Shared secrets for road warriors</A></H3>
+<P>You can use a shared secret to support a single road warrior
+ connecting to your gateway, and this is a reasonable thing to do in
+ some circumstances. Public key methods have advantages, discussed<A href="#choose">
+ above</A>, but they are not critical in this case.</P>
+<P>To do this, the line in ipsec.secrets(5) is something like:</P>
+<PRE>        10.0.0.1 0.0.0.0 : PSK &quot;jxTR1lnmSjuj33n4W51uW3kTR55luUmSmnlRUuWnkjRj3UuTV4T3USSu23Uk55nWu5TkTUnjT&quot;</PRE>
+ where the<VAR> 0.0.0.0</VAR> means that any IP address is acceptable.
+<P><STRONG>For more than one road warrior, shared secrets are<EM> not</EM>
+ recommended.</STRONG> If shared secrets are used, then when the
+ responder needs to look up the secret, all it knows about the sender is
+ an IP address. This is fine if the sender is at a fixed IP address
+ specified in the config file. It is also fine if only one road warrior
+ uses the wildcard<VAR> 0.0.0.0</VAR> address. However, if you have more
+ than one road warrior using shared secret authentication, then they
+ must all use that wildcard and therefore<STRONG> all road warriors
+ using PSK autentication must use the same secret</STRONG>. Obviously,
+ this is insecure.</P>
+<P><STRONG>For multiple road warriors, use public key authentication.</STRONG>
+ Each roadwarrior can then have its own identity (our<VAR> leftid=</VAR>
+ or<VAR> rightid=</VAR> parameters), its own public/private key pair,
+ and its own secure connection.</P>
+<H2><A name="prodman">Using manual keying in production</A></H2>
+<P>Generally,<A href="glossary.html#auto"> automatic keying</A> is
+ preferred over<A href="glossary.html#manual"> manual keying</A> for
+ production use because it is both easier to manage and more secure.
+ Automatic keying frees the admin from much of the burden of managing
+ keys securely, and can provide<A href="glossary.html#PFS"> perfect
+ forward secrecy</A>. This is discussed in more detail<A href="#man-auto">
+ above</A>.</P>
+<P>However, it is possible to use manual keying in production if that is
+ what you want to do. This might be necessary, for example, in order to
+ interoperate with some device that either does not provide automatic
+ keying or provides it in some version we cannot talk to.</P>
+<P>Note that with manual keying<STRONG> all security rests with the keys</STRONG>
+. If an adversary acquires your keys, you've had it. He or she can read
+ everything ever sent with those keys, including old messages he or she
+ may have archived.</P>
+<P>You need to<STRONG> be really paranoid about keys</STRONG> if you're
+ going to rely on manual keying for anything important.</P>
+<UL>
+<LI>keep keys in files with 600 permissions, owned by root</LI>
+<LI>be extremely careful about security of your gateway systems. Anyone
+ who breaks into a gateway and gains root privileges can get all your
+ keys and read everything ever encrypted with those keys, both old
+ messages he has archived and any new ones you may send.</LI>
+<LI>change keys regularly. This can be a considerable bother, (and
+ provides an excellent reason to consider automatic keying instead), but
+ it is<EM> absolutely essential</EM> for security. Consider a manually
+ keyed system in which you leave the same key in place for months:
+<UL>
+<LI>an attacker can have a very large sample of text sent with that key
+ to work with. This makes various cryptographic attacks much more likely
+ to succeed.</LI>
+<LI>The chances of the key being compromised in some non-cryptographic
+ manner -- a spy finds it on a discarded notepad, someone breaks into
+ your server or your building and steals it, a staff member is bribed,
+ tricked, seduced or coerced into revealing it, etc. -- also increase
+ over time.</LI>
+<LI>a successful attacker can read everything ever sent with that key.
+ This makes any successful attack extremely damaging.</LI>
+</UL>
+ It is clear that you must change keys often to have any useful
+ security. The only question is how often.</LI>
+<LI>use<A href="glossary.html#PGP"> PGP</A> or<A href="glossary.html#SSH">
+ SSH</A> for all key transfers</LI>
+<LI>don't edit files with keys in them when someone can look over your
+ shoulder</LI>
+<LI>worry about network security; could someone get keys by snooping
+ packets on the LAN between your X desktop and the gateway?</LI>
+<LI>lock up your backup tapes for the gateway system</LI>
+<LI>... and so on</LI>
+</UL>
+<P>Linux FreeS/WAN provides some facilities to help with this. In
+ particular, it is good policy to<STRONG> keep keys in separate files</STRONG>
+ so you can edit configuration information in /etc/ipsec.conf without
+ exposing keys to &quot;shoulder surfers&quot; or network snoops. We support this
+ with the<VAR> also=</VAR> and<VAR> include</VAR> syntax in<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A>.</P>
+<P>See the last example in our<A href="examples"> examples</A> file. In
+ the /etc/ipsec.conf<VAR> conn samplesep</VAR> section, it has the line:</P>
+<PRE>        also=samplesep-keys</PRE>
+<P>which tells the &quot;ipsec manual&quot; script to insert the configuration
+ description labelled &quot;samplesep-keys&quot; if it can find it. The
+ /etc/ipsec.conf file must also have a line such as:</P>
+<PRE>include ipsec.*.conf</PRE>
+<P>which tells it to read other files. One of those other files then
+ might contain the additional data:</P>
+<PRE>conn samplesep-keys
+  spi=0x200
+  esp=3des-md5-96
+  espenckey=0x01234567_89abcdef_02468ace_13579bdf_12345678_9abcdef0
+  espauthkey=0x12345678_9abcdef0_2468ace0_13579bdf</PRE>
+<P>The first line matches the label in the &quot;also=&quot; line, so the indented
+ lines are inserted. The net effect is exactly as if the inserted lines
+ had occurred in the original file in place of the &quot;also=&quot; line.</P>
+<P>Variables set here are:</P>
+<DL>
+<DT>spi</DT>
+<DD>A number needed by the manual keying code. Any 3-digit hex number
+ will do, but if you have more than one manual connection then<STRONG>
+ spi must be different</STRONG> for each connection.</DD>
+<DT>esp</DT>
+<DD>Options for<A href="glossary.html#ESP"> ESP</A> (Encapsulated
+ Security Payload), the usual IPsec encryption mode. Settings here are
+ for<A href="glossary.html#encryption"> encryption</A> using<A href="glossary.html#3DES">
+ triple DES</A> and<A href="glossary.html#authentication">
+ authentication</A> using<A href="glossary.html#MD5"> MD5</A>. Note that
+ encryption without authentication should not be used; it is insecure.</DD>
+<DT>espenkey</DT>
+<DD>Key for ESP encryption. Here, a 192-bit hex number for triple DES.</DD>
+<DT>espauthkey</DT>
+<DD>Key for ESP authentication. Here, a 128-bit hex number for MD5.</DD>
+</DL>
+<P><STRONG>Note</STRONG> that the<STRONG> example keys we supply</STRONG>
+ are intended<STRONG> only for testing</STRONG>. For real use, you
+ should go to automatic keying. If that is not possible, create your own
+ keys for manual mode and keep them secret</P>
+<P>Of course, any files containing keys<STRONG> must</STRONG> have 600
+ permissions and be owned by root.</P>
+<P>If you connect in this way to multiple sites, we recommend that you
+ keep keys for each site in a separate file and adopt some naming
+ convention that lets you pick them all up with a single &quot;include&quot; line.
+ This minimizes the risk of losing several keys to one error or attack
+ and of accidentally giving another site admin keys which he or she has
+ no business knowing.</P>
+<P>Also note that if you have multiple manually keyed connections on a
+ single machine, then the<VAR> spi</VAR> parameter must be different for
+ each one. Any 3-digit hex number is OK, provided they are different for
+ each connection. We reserve the range 0x100 to 0xfff for manual
+ connections. Pluto assigns SPIs from 0x1000 up for automatically keyed
+ connections.</P>
+<P>If<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf(5)</A> contains
+ keys for manual mode connections, then it too must have permissions<VAR>
+ rw-------</VAR>. We recommend instead that, if you must manual keying
+ in production, you keep the keys in separate files.</P>
+<P>Note also that<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf</A>
+ is installed with permissions<VAR> rw-r--r--</VAR>. If you plan to use
+ manually keyed connections for anything more than initial testing, you<B>
+ must</B>:</P>
+<UL>
+<LI>either change permissions to<VAR> rw-------</VAR></LI>
+<LI>or store keys separately in secure files and access them via include
+ statements in<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf</A>.</LI>
+</UL>
+<P>We recommend the latter method for all but the simplest
+ configurations.</P>
+<H3><A name="ranbits">Creating keys with ranbits</A></H3>
+<P>You can create new<A href="glossary.html#random"> random</A> keys
+ with the<A href="manpage.d/ipsec_ranbits.8.html"> ranbits(8)</A>
+ utility. For example, the commands:</P>
+<PRE>      umask 177
+      ipsec ranbits 192  &gt; temp
+      ipsec ranbits 128 &gt;&gt; temp</PRE>
+<P>create keys in the sizes needed for our default algorithms:</P>
+<UL>
+<LI>192-bit key for<A href="glossary.html#3DES"> 3DES</A> encryption
+<BR> (only 168 bits are used; parity bits are ignored)</LI>
+<LI>128-bit key for keyed<A href="glossary.html#MD5"> MD5</A>
+ authentication</LI>
+</UL>
+<P>If you want to use<A href="glossary.html#SHA"> SHA</A> instead of<A href="glossary.html#MD5">
+ MD5</A>, that requires a 160-bit key</P>
+<P>Note that any<STRONG> temporary files</STRONG> used must be kept<STRONG>
+ secure</STRONG> since they contain keys. That is the reason for the
+ umask command above. The temporary file should be deleted as soon as
+ you are done with it. You may also want to change the umask back to its
+ default value after you are finished working on keys.</P>
+<P>The ranbits utility may pause for a few seconds if not enough entropy
+ is available immediately. See ipsec_ranbits(8) and random(4) for
+ details. You may wish to provide some activity to feed entropy into the
+ system. For example, you might move the mouse around, type random
+ characters, or do<VAR> du /usr &gt; /dev/null</VAR> in the background.</P>
+<H2><A name="boot">Setting up connections at boot time</A></H2>
+<P>You can tell the system to set up connections automatically at boot
+ time by putting suitable stuff in /etc/ipsec.conf on both systems. The
+ relevant section of the file is labelled by a line reading<VAR> config
+ setup</VAR>.</P>
+<P>Details can be found in the<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A> man page. We also provide a file of<A href="examples">
+ example configurations</A>.</P>
+<P>The most likely options are something like:</P>
+<DL>
+<DT>interfaces=&quot;ipsec0=eth0 ipsec1=ppp0&quot;</DT>
+<DD>Tells KLIPS which interfaces to use. Up to four interfaces numbered
+ ipsec[0-3] are supported. Each interface can support an arbitrary
+ number of tunnels.
+<P>Note that for PPP, you give the ppp[0-9] device name here, not the
+ underlying device such as modem (or eth1 if you are using PPPoE).</P>
+</DD>
+<DT>interfaces=%defaultroute</DT>
+<DD>Alternative setting, useful in simple cases. KLIPS will pick up both
+ its interface and the next hop information from the settings of the
+ Linux default route.</DD>
+<DT>forwardcontrol=no</DT>
+<DD>Normally &quot;no&quot;. Set to &quot;yes&quot; if the IP forwarding option is disabled
+ in your network configuration. (This can be set as a kernel
+ configuration option or later. e.g. on Redhat, it's in
+ /etc/sysconfig/network and on SuSE you can adjust it with Yast.) Linux
+ FreeS/WAN will then enable forwarding when starting up and turn it off
+ when going down. This is used to ensure that no packets will be
+ forwarded before IPsec comes up and takes control.</DD>
+<DT>syslog=daemon.error</DT>
+<DD>Used in messages to the system logging daemon (syslogd) to specify
+ what type of software is sending the messages. If the settings are
+ &quot;daemon.error&quot; as in our example, then syslogd treats the messages as
+ error messages from a daemon.
+<P>Note that<A href="glossary.html#Pluto"> Pluto</A> does not currently
+ pay attention to this variable. The variable controls setup messages
+ only.</P>
+</DD>
+<DT>klipsdebug=</DT>
+<DD>Debug settings for<A href="glossary.html#KLIPS"> KLIPS</A>.</DD>
+<DT>plutodebug=</DT>
+<DD>Debug settings for<A href="glossary.html#Pluto"> Pluto</A>.</DD>
+<DT>... for both the above DEBUG settings</DT>
+<DD>Normally, leave empty as shown above for no debugging output.
+<BR> Use &quot;all&quot; for maximum information.
+<BR> See ipsec_klipsdebug(8) and ipsec_pluto(8) man page for other
+ options. Beware that if you set /etc/ipsec.conf to enable debug output,
+ your system's log files may get large quickly.</DD>
+<DT>dumpdir=/safe/directory</DT>
+<DD>Normally, programs started by ipsec setup don't crash. If they do,
+ by default, no core dump will be produced because such dumps would
+ contain secrets. If you find you need to debug such crashes, you can
+ set dumpdir to the name of a directory in which to collect the core
+ file.</DD>
+<DT>manualstart=</DT>
+<DD>List of manually keyed connections to be automatically started at
+ boot time. Useful for testing, but not for long term use. Connections
+ which are automatically started should also be automatically re-keyed.</DD>
+<DT>pluto=yes</DT>
+<DD>Whether to start<A href="glossary.html#Pluto"> Pluto</A> when ipsec
+ startup is done.
+<BR> This parameter is optional and defaults to &quot;yes&quot; if not present.
+<P>&quot;yes&quot; is strongly recommended for production use so that the keying
+ daemon (Pluto) will automatically re-key the connections regularly. The
+ ipsec-auto parameters ikelifetime, ipseclifetime and reykeywindow give
+ you control over frequency of rekeying.</P>
+</DD>
+<DT>plutoload=&quot;reno-van reno-adam reno-nyc&quot;</DT>
+<DD>List of tunnels (by name, e.g. fred-susan or reno-van in our
+ examples) to be loaded into Pluto's internal database at startup. In
+ this example, Pluto loads three tunnels into its database when it is
+ started.
+<P>If plutoload is &quot;%search&quot;, Pluto will load any connections whose
+ description includes &quot;auto=add&quot; or &quot;auto=start&quot;.</P>
+</DD>
+<DT>plutostart=&quot;reno-van reno-adam reno-nyc&quot;</DT>
+<DD>List of tunnels to attempt to negotiate when Pluto is started.
+<P>If plutostart is &quot;%search&quot;, Pluto will start any connections whose
+ description includes &quot;auto=start&quot;.</P>
+<P>Note that, for a connection intended to be permanent,<STRONG> both
+ gateways should be set try to start</STRONG> the tunnel. This allows
+ quick recovery if either gateway is rebooted or has its IPsec
+ restarted. If only one gateway is set to start the tunnel and the other
+ gateway restarts, the tunnel may not be rebuilt.</P>
+</DD>
+<DT>plutowait=no</DT>
+<DD>Controls whether Pluto waits for one tunnel to be established before
+ starting to negotiate the next. You might set this to &quot;yes&quot;
+<UL>
+<LI>if your gateway is a very limited machine and you need to conserve
+ resources.</LI>
+<LI>for debugging; the logs are clearer if only one connection is
+ brought up at a time</LI>
+</UL>
+ For a busy and resource-laden production gateway, you likely want &quot;no&quot;
+ so that connections are brought up in parallel and the whole process
+ takes less time.</DD>
+</DL>
+<P>The example assumes you are at the Reno office and will use IPsec to
+ Vancouver, New York City and Amsterdam.</P>
+<H2><A name="multitunnel">Multiple tunnels between the same two gateways</A>
+</H2>
+<P>Consider a pair of subnets, each with a security gateway, connected
+ via the Internet:</P>
+<PRE>         192.168.100.0/24           left subnet
+              |
+         192.168.100.1
+         North Gateway
+         101.101.101.101            left
+              |
+         101.101.101.1              left next hop
+         [Internet]
+         202.202.202.1              right next hop
+              |
+         202.202.202.202            right
+         South gateway
+         192.168.200.1
+              |
+         192.168.200.0/24           right subnet</PRE>
+<P>A tunnel specification such as:</P>
+<PRE>conn northnet-southnet
+      left=101.101.101.101
+      leftnexthop=101.101.101.1
+      leftsubnet=192.168.100.0/24
+      leftfirewall=yes
+      right=202.202.202.202
+      rightnexthop=202.202.202.1
+      rightsubnet=192.168.200.0/24
+      rightfirewall=yes</PRE>
+ will allow machines on the two subnets to talk to each other. You might
+ test this by pinging from polarbear (192.168.100.7) to penguin
+ (192.168.200.5).
+<P>However,<STRONG> this does not cover other traffic you might want to
+ secure</STRONG>. To handle all the possibilities, you might also want
+ these connection descriptions:</P>
+<PRE>conn northgate-southnet
+      left=101.101.101.101
+      leftnexthop=101.101.101.1
+      right=202.202.202.202
+      rightnexthop=202.202.202.1
+      rightsubnet=192.168.200.0/24
+      rightfirewall=yes
+
+conn northnet-southgate
+      left=101.101.101.101
+      leftnexthop=101.101.101.1
+      leftsubnet=192.168.100.0/24
+      leftfirewall=yes
+      right=202.202.202.202
+      rightnexthop=202.202.202.1</PRE>
+<P>Without these, neither gateway can do IPsec to the remote subnet.
+ There is no IPsec tunnel or eroute set up for the traffic.</P>
+<P>In our example, with the non-routable 192.168.* addresses used,
+ packets would simply be discarded. In a different configuration, with
+ routable addresses for the remote subnet,<STRONG> they would be sent
+ unencrypted</STRONG> since there would be no IPsec eroute and there
+ would be a normal IP route.</P>
+<P>You might also want:</P>
+<PRE>conn northgate-southgate
+      left=101.101.101.101
+      leftnexthop=101.101.101.1
+      right=202.202.202.202
+      rightnexthop=202.202.202.1</PRE>
+<P>This is required if you want the two gateways to speak IPsec to each
+ other.</P>
+<P>This requires a lot of duplication of details. Judicious use of<VAR>
+ also=</VAR> and<VAR> include</VAR> can reduce this problem.</P>
+<P>Note that, while FreeS/WAN supports all four tunnel types, not all
+ implementations do. In particular, some versions of Windows 2000 and
+ the freely downloadable version of PGP provide only &quot;client&quot;
+ functionality. You cannot use them as gateways with a subnet behind
+ them. To get that functionality, you must upgrade to Windows 2000
+ server or the commercially available PGP products.</P>
+<H3><A name="advroute">One tunnel plus advanced routing</A></H3>
+ It is also possible to use the new routing features in 2.2 and later
+ kernels to avoid most needs for multple tunnels. Here is one mailing
+ list message on the topic:
+<PRE>Subject: Re: linux-ipsec: IPSec packets not entering tunnel?
+   Date: Mon, 20 Nov 2000
+   From: Justin Guyett &lt;jfg@sonicity.com&gt;
+
+On Mon, 20 Nov 2000, Claudia Schmeing wrote:
+
+&gt; Right                                                         Left
+&gt;                      &quot;home&quot;                &quot;office&quot;
+&gt; 10.92.10.0/24 ---- 24.93.85.110 ========= 216.175.164.91 ---- 10.91.10.24/24
+&gt;
+&gt; I've created all four tunnels, and can ping to test each of them,
+&gt; *except* homegate-officenet.
+
+I keep wondering why people create all four tunnels.  Why not route
+traffic generated from home to 10.91.10.24/24 out ipsec0 with iproute2?
+And 99% of the time you don't need to access &quot;office&quot; directly, which
+means you can eliminate all but the subnet&lt;-&gt;subnet connection.</PRE>
+ and FreeS/WAN technical lead Henry Spencer's comment:
+<PRE>&gt; I keep wondering why people create all four tunnels.  Why not route
+&gt; traffic generated from home to 10.91.10.24/24 out ipsec0 with iproute2?
+
+This is feasible, given some iproute2 attention to source addresses, but
+it isn't something we've documented yet... (partly because we're still
+making some attempt to support 2.0.xx kernels, which can't do this, but
+mostly because we haven't caught up with it yet).
+
+&gt; And 99% of the time you don't need to access &quot;office&quot; directly, which
+&gt; means you can eliminate all but the subnet&lt;-&gt;subnet connection.
+
+Correct in principle, but people will keep trying to ping to or from the
+gateways during testing, and sometimes they want to run services on the
+gateway machines too.</PRE>
+
+<!-- Is this in the right spot in this document? -->
+<H2><A name="opp.gate">An Opportunistic Gateway</A></H2>
+<H3><A NAME="14_7_1">Start from full opportunism</A></H3>
+<P>Full opportunism allows you to initiate and receive opportunistic
+ connections on your machine. The remaining instructions in this section
+ assume you have first set up full opportunism on your gateway using<A HREF="quickstart.html#opp.incoming">
+ these instructions</A>. Both sets of instructions require mailing DNS
+ records to your ISP. Collect DNS records for both the gateway (above)
+ and the subnet nodes (below) before contacting your ISP.</P>
+<H3><A NAME="14_7_2">Reverse DNS TXT records for each protected machine</A>
+</H3>
+<P>You need these so that your Opportunistic peers can:</P>
+<UL>
+<LI>discover the gateway's address, knowing only the IP address that
+ packets are bound for</LI>
+<LI>verify that the gateway is authorised to encrypt for that endpoint</LI>
+</UL>
+<P>On the gateway, generate a TXT record with:</P>
+<PRE>    ipsec showhostkey --txt 192.0.2.11</PRE>
+<P>Use your gateway address in place of 192.0.2.11.</P>
+<P>You should see (keys are trimmed for clarity throughout our example):</P>
+<PRE>    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;</PRE>
+<P><B>This MUST BE the same key as in your gateway's TXT record, or
+ nothing will work.</B></P>
+<P>In a text file, make one copy of this TXT record for each subnet
+ node:</P>
+<PRE>    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;
+                                                                                
+    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;
+                                                                                
+    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;</PRE>
+<P>Above each entry, insert a line like this:</P>
+<PRE>    98.2.0.192.in-addr.arpa. IN PTR arthur.example.com.</PRE>
+<P>It must include:</P>
+<UL>
+<LI>The subnet node's address in reverse map format. For example,
+ 192.0.2.120 becomes<VAR> 120.2.0.192.in-addr.arpa.</VAR>. Note the
+ final period.</LI>
+<LI><VAR>IN PTR</VAR></LI>
+<LI>The node's name, ie.<VAR> arthur.example.com.</VAR>. Note the final
+ period.</LI>
+</UL>
+<P>The result will be a file of TXT records, like this:</P>
+<PRE>    98.2.0.192.in-addr.arpa. IN PTR arthur.example.com.
+    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;
+                                                                                
+    99.2.0.192.in-addr.arpa. IN PTR ford.example.com.
+    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;
+                                                                                
+    100.2.0.192.in-addr.arpa. IN PTR trillian.example.com.
+    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;</PRE>
+<H3><A NAME="14_7_3">Publish your records</A></H3>
+<P>Ask your ISP to publish all the reverse DNS records you have
+ collected. There may be a delay of up to 48 hours as the records
+ propagate.</P>
+<H3><A NAME="14_7_4">...and test them</A></H3>
+<P>Check a couple of records with commands like this one:</P>
+<PRE>    ipsec verify --host ford.example.com
+    ipsec verify --host trillian.example.com</PRE>
+<P>The<VAR> verify</VAR> command checks for TXT records for both the
+ subnet host and its gateway. You should see output like:</P>
+<PRE>    ...
+    Looking for TXT in reverse map: 99.2.0.192.in-addr.arpa [OK]
+    ...
+    Looking for TXT in reverse map: 11.2.0.192.in-addr.arpa   [OK]
+    ...
+    Looking for TXT in reverse map: 100.2.0.192.in-addr.arpa [OK]
+    ...
+    Looking for TXT in reverse map: 11.2.0.192.in-addr.arpa   [OK]
+    ...</PRE>
+<H3><A NAME="14_7_5">No Configuration Needed</A></H3>
+<P>FreeS/WAN 2.x ships with a built-in, automatically enabled OE
+ connection<VAR> conn packetdefault</VAR> which applies OE, if possible,
+ to all outbound traffic routed through the FreeS/WAN box. The<A HREF="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5) manual</A> describes this connection in detail. While the
+ effect is much the same as<VAR> private-or-clear</VAR>, the
+ implementation is different: notably, it does not use policy groups.</P>
+<P>You can create more complex OE configurations for traffic forwarded
+ through a FreeS/WAN box, as explained in our<A HREF="policygroups.html#policygroups">
+ policy groups document</A>, or disable OE using<A HREF="policygroups.html#disable_policygroups">
+ these instructions</A>.</P>
+<H2><A name="extruded.config">Extruded Subnets</A></H2>
+<P>What we call<A href="glossary.html#extruded"> extruded subnets</A>
+ are a special case of<A href="glossary.html#VPN.gloss"> VPNs</A>.</P>
+<P>If your buddy has some unused IP addresses, in his subnet far off at
+ the other side of the Internet, he can loan them to you... provided
+ that the connection between you and him is fast enough to carry all the
+ traffic between your machines and the rest of the Internet. In effect,
+ he &quot;extrudes&quot; a part of his address space over the network to you, with
+ your Internet traffic appearing to originate from behind his Internet
+ gateway.</P>
+<P>As far as the Internet is concerned, your new extruded net is behind
+ your buddy's gateway. You route all your packets for the Internet at
+ large out his gateway, and receive return packets the same way. You
+ route your local packets locally.</P>
+<P>Suppose your friend has a.b.c.0/24 and wants to give you
+ a.b.c.240/28. The initial situation is:</P>
+<PRE>    subnet           gateway          Internet
+  a.b.c.0/24    a.b.c.1    p.q.r.s</PRE>
+ where anything from the Internet destined for any machine in a.b.c.0/24
+ is routed via p.q.r.s and that gateway knows what to do from there.
+<P>Of course it is quite normal for various smaller subnets to exist
+ behind your friend's gateway. For example, your friend's company might
+ have a.b.c.16/28=development, a.b.c.32/28=marketing and so on. The
+ Internet neither knows not cares about this; it just delivers packets
+ to the p.q.r.s and lets the gateway do whatever needs to be done from
+ there.</P>
+<P>What we want to do is take a subnet, perhaps a.b.c.240/28, out of
+ your friend's physical location<EM> while still having your friend's
+ gateway route to it</EM>. As far as the Internet is concerned, you
+ remain behind that gateway.</P>
+<PRE>    subnet           gateway          Internet       your gate  extruded
+
+  a.b.c.0/24   a.b.c.1     p.q.r.s              d.e.f.g         a.b.c.240/28                
+
+                           ========== tunnel ==========</PRE>
+<P>The extruded addresses have to be a complete subnet.</P>
+<P>In our example, the friend's security gateway is also his Internet
+ gateway, but this is not necessary. As long as all traffic from the
+ Internet to his addresses passes through the Internet gate, the
+ security gate could be a machine behind that. The IG would need to
+ route all traffic for the extruded subnet to the SG, and the SG could
+ handle the rest.</P>
+<P>First, configure your subnet using the extruded addresses. Your
+ security gateway's interface to your subnet needs to have an extruded
+ address (possibly using a Linux<A href="glossary.html#virtual"> virtual
+ interface</A>, if it also has to have a different address). Your
+ gateway needs to have a route to the extruded subnet, pointing to that
+ interface. The other machines at your site need to have addresses in
+ that subnet, and default routes pointing to your gateway.</P>
+<P>If any of your friend's machines need to talk to the extruded subnet,<EM>
+ they</EM> need to have a route for the extruded subnet, pointing at his
+ gateway.</P>
+<P>Then set up an IPsec subnet-to-subnet tunnel between your gateway and
+ his, with your subnet specified as the extruded subnet, and his subnet
+ specified as &quot;0.0.0.0/0&quot;.</P>
+<P>The tunnel description should be:</P>
+<PRE>conn extruded
+        left=p.q.r.s
+        leftsubnet=0.0.0.0/0
+        right=d.e.f.g
+        rightsubnet=a.b.c.0/28</PRE>
+<P>If either side was doing firewalling for the extruded subnet before
+ the IPsec connection is set up, you'll need to poke holes in your<A HREF="firewall.html#firewall">
+ firewall</A> to allow packets through.</P>
+<P>And it all just works. Your SG routes traffic for 0.0.0.0/0 -- that
+ is, the whole Internet -- through the tunnel to his SG, which then
+ sends it onward as if it came from his subnet. When traffic for the
+ extruded subnet arrives at his SG, it gets sent through the tunnel to
+ your SG, which passes it to the right machine.</P>
+<P>Remember that when ipsec_manual or ipsec_auto takes a connection
+ down, it<EM> does not undo the route</EM> it made for that connection.
+ This lets you take a connection down and bring up a new one, or a
+ modified version of the old one, without having to rebuild the route it
+ uses and without any risk of packets which should use IPsec
+ accidentally going out in the clear. Because the route always points
+ into KLIPS, the packets will always go there. Because KLIPS temporarily
+ has no idea what to do with them (no eroute for them), they will be
+ discarded.</P>
+<P>If you<EM> do</EM> want to take the route down, this is what the
+ &quot;unroute&quot; operation in manual and auto is for. Just do an unroute after
+ doing the down.</P>
+<P>Note that the route for a connection may have replaced an existing
+ non-IPsec route. Nothing in Linux FreeS/WAN will put that pre-IPsec
+ route back. If you need it back, you have to create it with the route
+ command.</P>
+<H2><A name="roadvirt">Road Warrior with virtual IP address</A></H2>
+<P>Please note that<A HREF="http://www.freeswan.ca/download.php"> Super
+ FreeS/WAN</A> now features DHCP-over-IPsec, which is an alternate
+ procedure for Virtual IP address assignment.</P>
+<P></P>
+<P>Here is a mailing list message about another way to configure for
+ road warrior support:</P>
+<PRE>Subject: Re: linux-ipsec: understanding the vpn
+   Date: Thu, 28 Oct 1999 10:43:22 -0400
+   From: Irving Reid &lt;irving@nevex.com&gt;
+
+&gt;  local-------linux------internet------mobile
+&gt;  LAN        box                         user
+&gt;  ...
+
+&gt;  now when the mobile user connects to the linux box
+&gt;  it is given a virtual IP address, i have configured it to
+&gt;  be in the 10.x.x.x range. mobile user and linux box 
+&gt;  have a tunnel between them with these IP addresses.
+
+&gt;   Uptil this all is fine.
+
+If it is possible to configure your mobile client software *not* to
+use a virtual IP address, that will make your life easier. It is easier
+to configure FreeS/WAN to use the actual address the mobile user gets
+from its ISP.
+
+Unfortunately, some Windows clients don't let you choose.
+
+&gt;  what i would like to know is that how does the mobile
+&gt;  user communicate with other computers on the local
+&gt;  LAN , of course with the vpn ?
+
+&gt;   what IP address should the local LAN 
+&gt;  computers have ? I guess their default gateway 
+&gt;  should be the linux box ? and does the linux box need
+&gt;  to be a 2 NIC card box or one is fine.
+
+As someone else stated, yes, the Linux box would usually be the default
+IP gateway for the local lan.
+
+However...
+
+If you mobile user has software that *must* use a virtual IP address,
+the whole picture changes. Nobody has put much effort into getting
+FreeS/WAN to play well in this environment, but here's a sketch of one
+approach:
+
+Local Lan 1.0.0.0/24
+    |
+    +- Linux FreeS/WAN 1.0.0.2
+    |
+    | 1.0.0.1
+ Router
+    | 2.0.0.1
+    |
+Internet
+    |
+    | 3.0.0.1
+Mobile User
+      Virtual Address: 1.0.0.3
+
+Note that the Local Lan network (1.0.0.x) can be registered, routable
+addresses.
+
+Now, the Mobile User sets up an IPSec security association with the
+Linux box (1.0.0.2); it should ESP encapsulate all traffic to the
+network 1.0.0.x **EXCEPT** UDP port 500. 500/udp is required for the key
+negotiation, which needs to work outside of the IPSec tunnel.
+
+On the Linux side, there's a bunch of stuff you need to do by hand (for
+now). FreeS/WAN should correctly handle setting up the IPSec SA and
+routes, but I haven't tested it so this may not work...
+
+The FreeS/WAN conn should look like:
+
+conn mobile
+        right=1.0.0.2
+        rightsubnet=1.0.0.0/24
+        rightnexthop=1.0.0.1
+        left=0.0.0.0  # The infamous &quot;road warrior&quot;
+        leftsubnet=1.0.0.3/32
+
+Note that the left subnet contains *only* the remote host's virtual
+address.
+
+Hopefully the routing table on the FreeS/WAN box ends up looking like
+this:
+
+% netstat -rn
+Kernel IP routing table
+Destination     Gateway      Genmask         Flags   MSS Window  irtt Iface
+1.0.0.0         0.0.0.0      255.255.255.0   U      1500 0          0 eth0
+127.0.0.0       0.0.0.0      255.0.0.0       U      3584 0          0 lo
+0.0.0.0         1.0.0.1      0.0.0.0         UG     1500 0          0 eth0
+1.0.0.3         1.0.0.1      255.255.255.255 UG     1433 0          0 ipsec0
+
+So, if anybody sends a packet for 1.0.0.3 to the Linux box, it should
+get bundled up and sent through the tunnel. To get the packets for
+1.0.0.3 to the Linux box in the first place, you need to use &quot;proxy
+ARP&quot;.
+
+How this works is: when a host or router on the local Ethernet segment
+wants to send a packet to 1.0.0.3, it sends out an Ethernet level
+broadcast &quot;ARP request&quot;. If 1.0.0.3 was on the local LAN, it would
+reply, saying &quot;send IP packets for 1.0.0.3 to my Ethernet address&quot;.
+
+Instead, you need to set up the Linux box so that _it_ answers ARP
+requests for 1.0.0.3, even though that isn't its IP address. That
+convinces everyone else on the lan to send 1.0.0.3 packets to the Linux
+box, where the usual FreeS/WAN processing and routing take over.
+
+% arp -i eth0 -s 1.0.0.3 -D eth0 pub
+
+This says, if you see an ARP request on interface eth0 asking for
+1.0.0.3, respond with the Ethernet address of interface eth0.
+
+Now, as I said at the very beginning, if it is *at all* possible to
+configure your client *not* to use the virtual IP address, you can avoid
+this whole mess.</PRE>
+<H2><A name="dynamic">Dynamic Network Interfaces</A></H2>
+<P>Sometimes you have to cope with a situation where the network
+ interface(s) aren't all there at boot. The common example is notebooks
+ with PCMCIA.</P>
+<H3><A name="basicdyn">Basics</A></H3>
+<P>The key issue here is that the<VAR> config setup</VAR> section of the<VAR>
+ /etc/ipsec.conf</VAR> configuration file lists the connection between
+ ipsecN and hardware interfaces, in the<VAR> interfaces=</VAR> variable.
+ At any time when<VAR> ipsec setup start</VAR> or<VAR> ipsec setup
+ restart</VAR> is run this variable<STRONG> must</STRONG> correspond to
+ the current real situation. More precisely, it<STRONG> must not</STRONG>
+ mention any hardware interfaces which don't currently exist. The
+ difficulty is that an<VAR> ipsec setup start</VAR> command is normally
+ run at boot time so interfaces that are not up then are mis-handled.</P>
+<H3><A name="bootdyn">Boot Time</A></H3>
+<P>Normally, an<VAR> ipsec setup start</VAR> is run at boot time.
+ However, if the hardware situation at boot time is uncertain, one of
+ two things must be done.</P>
+<UL>
+<LI>One possibility is simply not to have IPsec brought up at boot time.
+ To do this:
+<PRE>        chkconfig --level 2345 ipsec off</PRE>
+ That's for modern Red Hats or other Linuxes with chkconfig. Systems
+ which lack this will require fiddling with symlinks in /etc/rc.d/rc?.d
+ or the equivalent.</LI>
+<LI>Another possibility is to bring IPsec up with no interfaces, which
+ is less aesthetically satisfying but simpler. Just put
+<PRE>        interfaces=</PRE>
+ in the configuration file. KLIPS and Pluto will be started, but won't
+ do anything.</LI>
+</UL>
+<H3><A name="changedyn">Change Time</A></H3>
+<P>When the hardware *is* in place, IPsec has to be made aware of it.
+ Someday there may be a nice way to do this.</P>
+<P>Right now, the way to do it is to fix the<VAR> /etc/ipsec.conf</VAR>
+ file appropriately, so<VAR> interfaces</VAR> reflects the new
+ situation, and then restart the IPsec subsystem. This does break any
+ existing IPsec connections.</P>
+<P>If IPsec wasn't brought up at boot time, do</P>
+<PRE>        ipsec setup start</PRE>
+ while if it was, do
+<PRE>        ipsec setup restart</PRE>
+ which won't be as quick.
+<P>If some of the hardware is to be taken out, before doing that, amend
+ the configuration file so interfaces no longer includes it, and do</P>
+<PRE>        ipsec setup restart</PRE>
+<P>Again, this breaks any existing connections.</P>
+<H2><A name="unencrypted">Unencrypted tunnels</A></H2>
+<P>Sometimes you might want to create a tunnel without encryption. Often
+ this is a bad idea, even if you have some data which need not be
+ private. See this<A href="ipsec.html#traffic.resist"> discussion</A>.</P>
+<P>The IPsec protocols provide two ways to do build such tunnels:</P>
+<DL>
+<DT>using ESP with null encryption</DT>
+<DD>not supported by FreeS/WAN</DD>
+<DT>using<A href="glossary.html#AH"> AH</A> without<A href="glossary.html#ESP">
+ ESP</A></DT>
+<DD>supported for manually keyed connections</DD>
+<DD>possible with explicit commands via<A href="manpage.d/ipsec_whack.8.html">
+ ipsec_whack(8)</A> (see this<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/02/msg00190.html">
+ list message</A>)</DD>
+<DD>not supported in the<A href="manpage.d/ipsec_auto.8.html">
+ ipsec_auto(8)</A> scripts.</DD>
+</DL>
+ One situation in which this comes up is when otherwise some data would
+ be encrypted twice. Alice wants a secure tunnel from her machine to
+ Bob's. Since she's behind one security gateway and he's behind another,
+ part of the tunnel that they build passes through the tunnel that their
+ site admins have built between the gateways. All of Alice and Bob's
+ messages are encrypted twice.
+<P>There are several ways to handle this.</P>
+<UL>
+<LI>Just accept the overhead of double encryption. The site admins might
+ choose this if any of the following apply:
+<UL>
+<LI>policy says encrypt everything (usually, it should)</LI>
+<LI>they don't entirely trust Alice and Bob (usually, if they don't have
+ to, they shouldn't)</LI>
+<LI>if they don't feel the saved cycles are worth the time they'd need
+ to build a non-encrypted tunnel for Alice and Bob's packets (often,
+ they aren't)</LI>
+</UL>
+</LI>
+<LI>Use a plain IP-in-IP tunnel. These are not well documented. A good
+ starting point is in the Linux kernel source tree, in
+ /usr/src/linux/drivers/net/README.tunnel.</LI>
+<LI>Use a manually-keyed AH-only tunnel.</LI>
+</UL>
+<P>Note that if Alice and Bob want end-to-end security, they must build
+ a tunnel end-to-end between their machines or use some other end-to-end
+ tool such as PGP or SSL that suits their data. The only question is
+ whether the admins build some special unencrypted tunnel for those
+ already-encrypted packets.</P>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="kernel.html">Previous</A>
+<A HREF="install.html">Next</A>
+</BODY>
+</HTML>
diff --git a/doc/background.html b/doc/background.html
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
+H5 { font-family: sans-serif }
+H6 { font-family: sans-serif }
+SUB { font-size: smaller }
+SUP { font-size: smaller }
+PRE { font-family: monospace }
+--></STYLE>
+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="config.html">Previous</A>
+<A HREF="user_examples.html">Next</A>
+<HR>
+<H1><A name="background">Linux FreeS/WAN background</A></H1>
+<P>This section discusses a number of issues which have three things in
+ common:</P>
+<UL>
+<LI>They are not specifically FreeS/WAN problems</LI>
+<LI>You may have to understand them to get FreeS/WAN working right</LI>
+<LI>They are not simple questions</LI>
+</UL>
+<P>Grouping them here lets us provide the explanations some users will
+ need without unduly complicating the main text.</P>
+<P>The explanations here are intended to be adequate for FreeS/WAN
+ purposes (please comment to the<A href="mail.html"> users mailing list</A>
+ if you don't find them so), but they are not trying to be complete or
+ definitive. If you need more information, see the references provided
+ in each section.</P>
+<H2><A name="dns.background">Some DNS background</A></H2>
+<P><A href="glossary.html#carpediem">Opportunistic encryption</A>
+ requires that the gateway systems be able to fetch public keys, and
+ other IPsec-related information, from each other's DNS (Domain Name
+ Service) records.</P>
+<P><A href="glossary.html#DNS">DNS</A> is a distributed database that
+ maps names to IP addresses and vice versa.</P>
+<P>Much good reference material is available for DNS, including:</P>
+<UL>
+<LI>the<A href="http://www.linuxdoc.org/HOWTO/DNS-HOWTO.html"> DNS HowTo</A>
+</LI>
+<LI>the standard<A href="biblio.html#DNS.book"> DNS reference</A> book</LI>
+<LI><A href="http://www.linuxdoc.org/LDP/nag2/index.html">Linux Network
+ Administrator's Guide</A></LI>
+<LI><A href="http://www.nominum.com/resources/whitepapers/bind-white-paper.html">
+BIND overview</A></LI>
+<LI><A href="http://www.nominum.com/resources/documentation/Bv9ARM.pdf">
+BIND 9 Administrator's Reference</A></LI>
+</UL>
+<P>We give only a brief overview here, intended to help you use DNS for
+ FreeS/WAN purposes.</P>
+<H3><A name="forward.reverse">Forward and reverse maps</A></H3>
+<P>Although the implementation is distributed, it is often useful to
+ speak of DNS as if it were just two enormous tables:</P>
+<UL>
+<LI>the forward map: look up a name, get an IP address</LI>
+<LI>the reverse map: look up an IP address, get a name</LI>
+</UL>
+<P>Both maps can optionally contain additional data. For opportunistic
+ encryption, we insert the data need for IPsec authentication.</P>
+<P>A system named gateway.example.com with IP address 10.20.30.40 should
+ have at least two DNS records, one in each map:</P>
+<DL>
+<DT>gateway.example.com. IN A 10.20.30.40</DT>
+<DD>used to look up the name and get an IP address</DD>
+<DT>40.30.20.10.in-addr.arpa. IN PTR gateway.example.com.</DT>
+<DD>used for reverse lookups, looking up an address to get the
+ associated name. Notice that the digits here are in reverse order; the
+ actual address is 10.20.30.40 but we use 40.30.20.10 here.</DD>
+</DL>
+<H3><A NAME="17_1_2">Hierarchy and delegation</A></H3>
+<P>For both maps there is a hierarchy of DNS servers and a system of
+ delegating authority so that, for example:</P>
+<UL>
+<LI>the DNS administrator for example.com can create entries of the form<VAR>
+ name</VAR>.example.com</LI>
+<LI>the example.com admin cannot create an entry for counterexample.com;
+ only someone with authority for .com can do that</LI>
+<LI>an admin might have authority for 20.10.in-addr.arpa.</LI>
+<LI>in either map, authority can be delegated
+<UL>
+<LI>the example.com admin could give you authority for
+ westcoast.example.com</LI>
+<LI>the 20.10.in-addr.arpa admin could give you authority for
+ 30.20.10.in-addr.arpa</LI>
+</UL>
+</LI>
+</UL>
+<P>DNS zones are the units of delegation. There is a hierarchy of zones.</P>
+<H3><A NAME="17_1_3">Syntax of DNS records</A></H3>
+<P>Returning to the example records:</P>
+<PRE>        gateway.example.com. IN A 10.20.30.40
+        40.30.20.10.in-addr.arpa. IN PTR gateway.example.com.</PRE>
+<P>some syntactic details are:</P>
+<UL>
+<LI>the IN indicates that these records are for<STRONG> In</STRONG>
+ternet addresses</LI>
+<LI>The final periods in '.com.' and '.arpa.' are required. They
+ indicate the root of the domain name system.</LI>
+</UL>
+<P>The capitalised strings after IN indicate the type of record.
+ Possible types include:</P>
+<UL>
+<LI><STRONG>A</STRONG>ddress, for forward lookups</LI>
+<LI><STRONG>P</STRONG>oin<STRONG>T</STRONG>e<STRONG>R</STRONG>, for
+ reverse lookups</LI>
+<LI><STRONG>C</STRONG>anonical<STRONG> NAME</STRONG>, records to support
+ aliasing, multiple names for one address</LI>
+<LI><STRONG>M</STRONG>ail e<STRONG>X</STRONG>change, used in mail
+ routing</LI>
+<LI><STRONG>SIG</STRONG>nature, used in<A href="glossary.html#SDNS">
+ secure DNS</A></LI>
+<LI><STRONG>KEY</STRONG>, used in<A href="glossary.html#SDNS"> secure
+ DNS</A></LI>
+<LI><STRONG>T</STRONG>e<STRONG>XT</STRONG>, a multi-purpose record type</LI>
+</UL>
+<P>To set up for opportunistic encryption, you add some TXT records to
+ your DNS data. Details are in our<A href="quickstart.html"> quickstart</A>
+ document.</P>
+<H3><A NAME="17_1_4">Cacheing, TTL and propagation delay</A></H3>
+<P>DNS information is extensively cached. With no caching, a lookup by
+ your system of &quot;www.freeswan.org&quot; might involve:</P>
+<UL>
+<LI>your system asks your nameserver for &quot;www.freeswan.org&quot;</LI>
+<LI>local nameserver asks root server about &quot;.org&quot;, gets reply</LI>
+<LI>local nameserver asks .org nameserver about &quot;freeswan.org&quot;, gets
+ reply</LI>
+<LI>local nameserver asks freeswan.org nameserver about
+ &quot;www.freeswan.org&quot;, gets reply</LI>
+</UL>
+<P>However, this can be a bit inefficient. For example, if you are in
+ the Phillipines, the closest a root server is in Japan. That might send
+ you to a .org server in the US, and then to freeswan.org in Holland. If
+ everyone did all those lookups every time they clicked on a web link,
+ the net would grind to a halt.</P>
+<P>Nameservers therefore cache information they look up. When you click
+ on another link at www.freeswan.org, your local nameserver has the IP
+ address for that server in its cache, and no further lookups are
+ required.</P>
+<P>Intermediate results are also cached. If you next go to
+ lists.freeswan.org, your nameserver can just ask the freeswan.org
+ nameserver for that address; it does not need to query the root or .org
+ nameservers because it has a cached address for the freeswan.org zone
+ server.</P>
+<P>Of course, like any cacheing mechanism, this can create problems of
+ consistency. What if the administrator for freeswan.org changes the IP
+ address, or the authentication key, for www.freeswan.org? If you use
+ old information from the cache, you may get it wrong. On the other
+ hand, you cannot afford to look up fresh information every time. Nor
+ can you expect the freeswan.org server to notify you; that isn't in the
+ protocols.</P>
+<P>The solution that is in the protocols is fairly simple. Cacheable
+ records are marked with Time To Live (TTL) information. When the time
+ expires, the caching server discards the record. The next time someone
+ asks for it, the server fetches a fresh copy. Of course, a server may
+ also discard records before their TTL expires if it is running out of
+ cache space.</P>
+<P>This implies that there will be some delay before the new version of
+ a changed record propagates around the net. Until the TTLs on all
+ copies of the old record expire, some users will see it because that is
+ what is in their cache. Other users may see the new record immediately
+ because they don't have an old one cached.</P>
+<H2><A name="MTU.trouble">Problems with packet fragmentation</A></H2>
+<P>It seems, from mailing list reports, to be moderately common for
+ problems to crop up in which small packets pass through the IPsec
+ tunnels just fine but larger packets fail.</P>
+<P>These problems are caused by various devices along the way
+ mis-handling either packet fragments or<A href="glossary.html#pathMTU">
+ path MTU discovery</A>.</P>
+<P>IPsec makes packets larger by adding an ESP or AH header. This can
+ tickle assorted bugs in fragment handling in routers and firewalls, or
+ in path MTU discovery mechanisms, and cause a variety of symptoms which
+ are both annoying and, often, quite hard to diagnose.</P>
+<P>An explanation from project technical lead Henry Spencer:</P>
+<PRE>The problem is IP fragmentation; more precisely, the problem is that the
+second, third, etc. fragments of an IP packet are often difficult for
+filtering mechanisms to classify.
+
+Routers cannot rely on reassembling the packet, or remembering what was in
+earlier fragments, because the fragments may be out of order or may even
+follow different routes.  So any general, worst-case filtering decision
+pretty much has to be made on each fragment independently.  (If the router
+knows that it is the only route to the destination, so all fragments
+*must* pass through it, reassembly would be possible... but most routers
+don't want to bother with the complications of that.)
+
+All fragments carry roughly the original IP header, but any higher-level
+header is (for IP purposes) just the first part of the packet data... so
+only the first fragment carries that.  So, for example, on examining the
+second fragment of a TCP packet, you could tell that it's TCP, but not
+what port number it is destined for -- that information is in the TCP
+header, which appears in the first fragment only. 
+
+The result of this classification difficulty is that stupid routers and
+over-paranoid firewalls may just throw fragments away.  To get through
+them, you must reduce your MTU enough that fragmentation will not occur.
+(In some cases, they might be willing to attempt reassembly, but have very
+limited resources to devote to it, meaning that packets must be small and
+fragments few in number, leading to the same conclusion:  smaller MTU.)</PRE>
+<P>In addition to the problem Henry describes, you may also have trouble
+ with<A href="glossary.html#pathMTU"> path MTU discovery</A>.</P>
+<P>By default, FreeS/WAN uses a large<A href="glossary.html#MTU"> MTU</A>
+ for the ipsec device. This avoids some problems, but may complicate
+ others. Here's an explanation from Claudia:</P>
+<PRE>Here are a couple of pieces of background information. Apologies if you
+have seen these already. An excerpt from one of my old posts:
+
+    An MTU of 16260 on ipsec0 is usual. The IPSec device defaults to this 
+    high MTU so that it does not fragment incoming packets before encryption 
+    and encapsulation. If after IPSec processing packets are larger than 1500,
+    [ie. the mtu of eth0] then eth0 will fragment them. 
+
+    Adding IPSec headers adds a certain number of bytes to each packet. 
+    The MTU of the IPSec interface refers to the maximum size of the packet
+    before the IPSec headers are added. In some cases, people find it helpful 
+    to set ipsec0's MTU to 1500-(IPSec header size), which IIRC is about 1430.
+
+    That way, the resulting encapsulated packets don't exceed 1500. On most 
+    networks, packets less than 1500 will not need to be fragmented.
+
+and... (from Henry Spencer)
+
+    The way it *ought* to work is that the MTU advertised by the ipsecN
+    interface should be that of the underlying hardware interface, less a
+    pinch for the extra headers needed. 
+
+    Unfortunately, in certain situations this breaks many applications.
+    There is a widespread implicit assumption that the smallest MTUs are 
+    at the ends of paths, not in the middle, and another that MTUs are 
+    never less than 1500.  A lot of code is unprepared to handle paths 
+    where there is an &quot;interior minimum&quot; in the MTU, especially when it's 
+    less than 1500. So we advertise a big MTU and just let the resulting 
+    big packets fragment.
+
+This usually works, but we do get bitten in cases where some intermediate
+point can't handle all that fragmentation.  We can't win on this one.</PRE>
+<P>The MTU can be changed with an<VAR> overridemtu=</VAR> statement in
+ the<VAR> config setup</VAR> section of<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf.5</A>.</P>
+<P>For a discussion of MTU issues and some possible solutions using
+ Linux advanced routing facilities, see the<A href="http://www.linuxguruz.org/iptables/howto/2.4routing-15.html#ss15.6">
+ Linux 2.4 Advanced Routing HOWTO</A>. For a discussion of MTU and NAT
+ (Network Address Translation), see<A HREF="http://harlech.math.ucla.edu/services/ipsec.html">
+ James Carter's MTU notes</A>.</P>
+<H2><A name="nat.background">Network address translation (NAT)</A></H2>
+<P><STRONG>N</STRONG>etwork<STRONG> A</STRONG>ddress<STRONG> T</STRONG>
+ranslation is a service provided by some gateway machines. Calling it
+ NAPT (adding the word<STRONG> P</STRONG>ort) would be more precise, but
+ we will follow the widespread usage.</P>
+<P>A gateway doing NAT rewrites the headers of packets it is forwarding,
+ changing one or more of:</P>
+<UL>
+<LI>source address</LI>
+<LI>source port</LI>
+<LI>destination address</LI>
+<LI>destination port</LI>
+</UL>
+<P>On Linux 2.4, NAT services are provided by the<A href="http://netfilter.samba.org">
+ netfilter(8)</A> firewall code. There are several<A href="http://netfilter.samba.org/documentation/index.html#HOWTO">
+ Netfilter HowTos</A> including one on NAT.</P>
+<P>For older versions of Linux, this was referred to as &quot;IP masquerade&quot;
+ and different tools were used. See this<A href="http://www.e-infomax.com/ipmasq/">
+ resource page</A>.</P>
+<P>Putting an IPsec gateway behind a NAT gateway is not recommended. See
+ our<A href="firewall.html#NAT"> firewalls document</A>.</P>
+<H3><A NAME="17_3_1">NAT to non-routable addresses</A></H3>
+<P>The most common application of NAT uses private<A href="glossary.html#non-routable">
+ non-routable</A> addresses.</P>
+<P>Often a home or small office network will have:</P>
+<UL>
+<LI>one connection to the Internet</LI>
+<LI>one assigned publicly visible IP address</LI>
+<LI>several machines that all need access to the net</LI>
+</UL>
+<P>Of course this poses a problem since several machines cannot use one
+ address. The best solution might be to obtain more addresses, but often
+ this is impractical or uneconomical.</P>
+<P>A common solution is to have:</P>
+<UL>
+<LI><A href="glossary.html#non-routable">non-routable</A> addresses on
+ the local network</LI>
+<LI>the gateway machine doing NAT</LI>
+<LI>all packets going outside the LAN rewritten to have the gateway as
+ their source address</LI>
+</UL>
+<P>The client machines are set up with reserved<A href="glossary.html#non-routable">
+ non-routable</A> IP addresses defined in RFC 1918. The masquerading
+ gateway, the machine with the actual link to the Internet, rewrites
+ packet headers so that all packets going onto the Internet appear to
+ come from one IP address, that of its Internet interface. It then gets
+ all the replies, does some table lookups and more header rewriting, and
+ delivers the replies to the appropriate client machines.</P>
+<P>As far as anyone else on the Internet is concerned, the systems
+ behind the gateway are completely hidden. Only one machine with one IP
+ address is visible.</P>
+<P>For IPsec on such a gateway, you can entirely ignore the NAT in:</P>
+<UL>
+<LI><A href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</A></LI>
+<LI>firewall rules affecting your Internet-side interface</LI>
+</UL>
+<P>Those can be set up exactly as they would be if your gateway had no
+ other systems behind it.</P>
+<P>You do, however, have to take account of the NAT in firewall rules
+ which affect packet forwarding.</P>
+<H3><A NAME="17_3_2">NAT to routable addresses</A></H3>
+<P>NAT to routable addresses is also possible, but is less common and
+ may make for rather tricky routing problems. We will not discuss it
+ here. See the<A href="http://netfilter.samba.org/documentation/index.html#HOWTO">
+ Netfilter HowTos</A>.</P>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="config.html">Previous</A>
+<A HREF="user_examples.html">Next</A>
+</BODY>
+</HTML>
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+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
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+<A HREF="rfc.html">Next</A>
+<HR>
+<H1><A name="biblio">Bibliography for the Linux FreeS/WAN project</A></H1>
+<P>For extensive bibliographic links, see the<A href="http://liinwww.ira.uka.de/bibliography/index.html">
+ Collection of Computer Science Bibliographies</A></P>
+<P>See our<A href="web.html"> web links</A> for material available
+ online.</P>
+<HR><A name="adams"> Carlisle Adams and Steve Lloyd<CITE> Understanding
+ Public Key Infrastructure</CITE>
+<BR></A> Macmillan 1999 ISBN 1-57870-166-x
+<P>An overview, mainly concentrating on policy and strategic issues
+ rather than the technical details. Both authors work for<A href="glossary.html#PKI">
+ PKI</A> vendor<A href="http://www.entrust.com/"> Entrust</A>.</P>
+<HR><A name="DNS.book"> Albitz, Liu &amp; Loukides<CITE> DNS &amp; BIND</CITE>
+ 3rd edition
+<BR></A> O'Reilly 1998 ISBN 1-56592-512-2
+<P>The standard reference on the<A href="glossary.html#DNS"> Domain Name
+ Service</A> and<A href="glossary.html#BIND"> Berkeley Internet Name
+ Daemon</A>.</P>
+<HR><A name="anderson"> Ross Anderson</A>,<CITE> Security Engineering -
+ a Guide to Building Dependable Distributed Systems</CITE>
+<BR> Wiley, 2001, ISBN 0471389226
+<P>Easily the best book for the security professional I have seen.<STRONG>
+ Highly recommended</STRONG>. See the<A href="http://www.cl.cam.ac.uk/~rja14/book.html">
+ book web page</A>.</P>
+<P>This is quite readable, but Schneier's<A href="#secrets"> Secrets and
+ Lies</A> might be an easier introduction.</P>
+<HR><A name="puzzle"> Bamford<CITE> The Puzzle Palace, A report on NSA,
+ Americas's most Secret Agency</CITE>
+<BR> Houghton Mifflin 1982 ISBN 0-395-31286-8</A>
+<HR> Bamford<CITE> Body of Secrets</CITE>
+<P>The sequel.</P>
+<HR><A name="bander"> David Bander</A>,<CITE> Linux Security Toolkit</CITE>
+<BR> IDG Books, 2000, ISBN: 0764546902
+<P>This book has a short section on FreeS/WAN and includes Caldera Linux
+ on CD.</P>
+<HR><A name="CZR"> Chapman, Zwicky &amp; Russell</A>,<CITE> Building
+ Internet Firewalls</CITE>
+<BR> O'Reilly 1995 ISBN 1-56592-124-0
+<HR><A name="firewall.book"> Cheswick and Bellovin</A><CITE> Firewalls
+ and Internet Security: Repelling the Wily Hacker</CITE>
+<BR> Addison-Wesley 1994 ISBN 0201633574
+<P>A fine book on firewalls in particular and security in general from
+ two of AT&amp;T's system adminstrators.</P>
+<P>Bellovin has also done a number of<A href="web.html#papers"> papers</A>
+ on IPsec and co-authored a<A href="intro.html#applied"> paper</A> on a
+ large FreeS/WAN application.</P>
+<HR><A name="comer"> Comer<CITE> Internetworking with TCP/IP</CITE>
+<BR> Prentice Hall</A>
+<UL>
+<LI>Vol. I: Principles, Protocols, &amp; Architecture, 3rd Ed. 1995
+ ISBN:0-13-216987-8</LI>
+<LI>Vol. II: Design, Implementation, &amp; Internals, 2nd Ed. 1994
+ ISBN:0-13-125527-4</LI>
+<LI>Vol. III: Client/Server Programming &amp; Applications
+<UL>
+<LI>AT&amp;T TLI Version 1994 ISBN:0-13-474230-3</LI>
+<LI>BSD Socket Version 1996 ISBN:0-13-260969-X</LI>
+<LI>Windows Sockets Version 1997 ISBN:0-13-848714-6</LI>
+</UL>
+</LI>
+</UL>
+<P>If you need to deal with the details of the network protocols, read
+ either this series or the<A href="#stevens"> Stevens and Wright</A>
+ series before you start reading the RFCs.</P>
+<HR><A name="diffie"> Diffie and Landau</A><CITE> Privacy on the Line:
+ The Politics of Wiretapping and Encryption</CITE>
+<BR> MIT press 1998 ISBN 0-262-04167-7 (hardcover) or 0-262-54100-9
+<BR>
+<HR><A name="d_and_hark"> Doraswamy and Harkins<CITE> IP Sec: The New
+ Security Standard for the Internet, Intranets and Virtual Private
+ Networks</CITE>
+<BR> Prentice Hall 1999 ISBN: 0130118982</A>
+<HR><A name="EFF"> Electronic Frontier Foundation<CITE> Cracking DES:
+ Secrets of Encryption Research, Wiretap Politics and Chip Design</CITE>
+<BR></A> O'Reilly 1998 ISBN 1-56592-520-3
+<P>To conclusively demonstrate that DES is inadequate for continued use,
+ the<A href="glossary.html#EFF"> EFF</A> built a machine for just over
+ $200,000 that breaks DES encryption in under five days on average,
+ under nine in the worst case.</P>
+<P>The book provides details of their design and, perhaps even more
+ important, discusses why they felt the project was necessary.
+ Recommended for anyone interested in any of the three topics mentioned
+ in the subtitle.</P>
+<P>See also the<A href="http://www.eff.org/descracker.html"> EFF page on
+ this project</A> and our discussion of<A href="politics.html#desnotsecure">
+ DES insecurity</A>.</P>
+<HR> Martin Freiss<CITE> Protecting Networks with SATAN</CITE>
+<BR> O'Reilly 1998 ISBN 1-56592-425-8
+<BR> translated from a 1996 work in German
+<P>SATAN is a Security Administrator's Tool for Analysing Networks. This
+ book is a tutorial in its use.</P>
+<HR> Gaidosch and Kunzinger<CITE> A Guide to Virtual Private Networks</CITE>
+<BR> Prentice Hall 1999 ISBN: 0130839647
+<HR><A name="Garfinkel"> Simson Garfinkel</A><CITE> Database Nation: the
+ death of privacy in the 21st century</CITE>
+<BR> O'Reilly 2000 ISBN 1-56592-653-6
+<P>A thoughtful and rather scary book.</P>
+<HR><A name="PGP"> Simson Garfinkel</A><CITE> PGP: Pretty Good Privacy</CITE>
+<BR> O'Reilly 1995 ISBN 1-56592-098-8
+<P>An excellent introduction and user manual for the<A href="glossary.html#PGP">
+ PGP</A> email-encryption package. PGP is a good package with a complex
+ and poorly-designed user interface. This book or one like it is a must
+ for anyone who has to use it at length.</P>
+<P>The book covers using PGP in Unix, PC and Macintosh environments,
+ plus considerable background material on both the technical and
+ political issues around cryptography.</P>
+<P>The book is now seriously out of date. It does not cover recent
+ developments such as commercial versions since PGP 5, the Open PGP
+ standard or GNU PG..</P>
+<HR><A name="practical"> Garfinkel and Spafford</A><CITE> Practical Unix
+ Security</CITE>
+<BR> O'Reilly 1996 ISBN 1-56592-148-8
+<P>A standard reference.</P>
+<P>Spafford's web page has an excellent collection of<A href="http://www.cs.purdue.edu/coast/hotlist">
+ crypto and security links</A>.</P>
+<HR><A name="Kahn"> David Kahn</A><CITE> The Codebreakers: the
+ Comprehensive History of Secret Communications from Ancient Times to
+ the Internet</CITE>
+<BR> second edition Scribner 1996 ISBN 0684831309
+<P>A history of codes and code-breaking from ancient Egypt to the 20th
+ century. Well-written and exhaustively researched.<STRONG> Highly
+ recommended</STRONG>, even though it does not have much on computer
+ cryptography.</P>
+<HR> David Kahn<CITE> Seizing the Enigma, The Race to Break the German
+ U-Boat codes, 1939-1943</CITE>
+<BR> Houghton Mifflin 1991 ISBN 0-395-42739-8
+<HR><A name="kirch"> Olaf Kirch</A><CITE> Linux Network Administrator's
+ Guide</CITE>
+<BR> O'Reilly 1995 ISBN 1-56592-087-2
+<P>Now becoming somewhat dated in places, but still a good introductory
+ book and general reference.</P>
+<HR><A name="LinVPN"> Kolesnikov and Hatch</A>,<CITE> Building Linux
+ Virtual Private Networks (VPNs)</CITE>
+<BR> New Riders 2002
+<P>This has had a number of favorable reviews, including<A href="http://www.slashdot.org/article.pl?sid=02/02/27/0115214&amp;mode=thread&amp;tid=172">
+ this one</A> on Slashdot. The book has a<A href="http://www.buildinglinuxvpns.net/">
+ web site</A>.</P>
+<HR><A name="RFCs"> Pete Loshin<CITE> Big Book of IPsec RFCs</CITE>
+<BR> Morgan Kaufmann 2000 ISBN: 0-12-455839-9</A>
+<HR><A name="crypto"> Steven Levy<CITE> Crypto: How the Code Rebels Beat
+ the Government -- Saving Privacy in the Digital Age</CITE></A>
+<BR> Penguin 2001, ISBN 0-670--85950-8
+<P><STRONG>Highly recommended</STRONG>. A fine history of recent (about
+ 1970-2000) developments in the field, and the related political
+ controversies. FreeS/WAN project founder and leader John Gilmore
+ appears several times.</P>
+<P>The book does not cover IPsec or FreeS/WAN, but this project is very
+ much another battle in the same war. See our discussion of the<A href="politics.html">
+ politics</A>.</P>
+<HR><A name="GTR"> Matyas, Anderson et al.</A><CITE> The Global Trust
+ Register</CITE>
+<BR> Northgate Consultants Ltd 1998 ISBN: 0953239705
+<BR> hard cover edition MIT Press 1999 ISBN 0262511053
+<P>From<A href="http://www.cl.cam.ac.uk/Research/Security/Trust-Register">
+ their web page:</A></P>
+<BLOCKQUOTE> This book is a register of the fingerprints of the world's
+ most important public keys; it implements a top-level certification
+ authority (CA) using paper and ink rather than in an electronic system.</BLOCKQUOTE>
+<HR><A name="handbook"> Menezies, van Oorschot and Vanstone<CITE>
+ Handbook of Applied Cryptography</CITE></A>
+<BR> CRC Press 1997
+<BR> ISBN 0-8493-8523-7
+<P>An excellent reference. Read<A href="#schneier"> Schneier</A> before
+ tackling this.</P>
+<HR> Michael Padlipsky<CITE> Elements of Networking Style</CITE>
+<BR> Prentice-Hall 1985 ISBN 0-13-268111-0 or 0-13-268129-3
+<P>Probably<STRONG> the funniest technical book ever written</STRONG>,
+ this is a vicious but well-reasoned attack on the OSI &quot;seven layer
+ model&quot; and all that went with it. Several chapters of it are also
+ available as RFCs 871 to 875.</P>
+<HR><A name="matrix"> John S. Quarterman</A><CITE> The Matrix: Computer
+ Networks and Conferencing Systems Worldwide</CITE>
+<BR> Digital Press 1990 ISBN 155558-033-5
+<BR> Prentice-Hall ISBN 0-13-565607-9
+<P>The best general treatment of computer-mediated communication we have
+ seen. It naturally has much to say about the Internet, but also covers
+ UUCP, Fidonet and so on.</P>
+<HR><A name="ranch"> David Ranch</A><CITE> Securing Linux Step by Step</CITE>
+<BR> SANS Institute, 1999
+<P><A href="http://www.sans.org/">SANS</A> is a respected organisation,
+ this guide is part of a well-known series, and Ranch has previously
+ written the useful<A href=" http://www.ecst.csuchico.edu/~dranch/LINUX/index-linux.html#trinityos">
+ Trinity OS</A> guide to securing Linux, so my guess would be this is a
+ pretty good book. I haven't read it yet, so I'm not certain. It can be
+ ordered online from<A href="http://www.sans.org/"> SANS</A>.</P>
+<P>Note (Mar 1, 2002): a new edition with different editors in the
+ works. Expect it this year.</P>
+<HR><A name="schneier"> Bruce Schneier</A><CITE> Applied Cryptography,
+ Second Edition</CITE>
+<BR> John Wiley &amp; Sons, 1996
+<BR> ISBN 0-471-12845-7 hardcover
+<BR> ISBN 0-471-11709-9 paperback
+<P>A standard reference on computer cryptography. For more recent
+ essays, see the<A href="http://www.counterpane.com/"> author's
+ company's web site</A>.</P>
+<HR><A name="secrets"> Bruce Schneier</A><CITE> Secrets and Lies</CITE>
+<BR> Wiley 2000, ISBN 0-471-25311-1
+<P>An interesting discussion of security and privacy issues, written
+ with more of an &quot;executive overview&quot; approach rather than a narrow
+ focus on the technical issues.<STRONG> Highly recommended</STRONG>.</P>
+<P>This is worth reading even if you already understand security issues,
+ or think you do. To go deeper, follow it with Anderson's<A href="#anderson">
+ Security Engineering</A>.</P>
+<HR><A name="VPNbook"> Scott, Wolfe and Irwin<CITE> Virtual Private
+ Networks</CITE></A>
+<BR> 2nd edition, O'Reilly 1999 ISBN: 1-56592-529-7
+<P>This is the only O'Reilly book, out of a dozen I own, that I'm
+ disappointed with. It deals mainly with building VPNs with various
+ proprietary tools --<A href="glossary.html#PPTP"> PPTP</A>,<A href="glossary.html#SSH">
+ SSH</A>, Cisco PIX, ... -- and touches only lightly on IPsec-based
+ approaches.</P>
+<P>That said, it appears to deal competently with what it does cover and
+ it has readable explanations of many basic VPN and security concepts.
+ It may be exactly what some readers require, even if I find the
+ emphasis unfortunate.</P>
+<HR><A name="LASG"> Kurt Seifried<CITE> Linux Administrator's Security
+ Guide</CITE></A>
+<P>Available online from<A href="http://www.securityportal.com/lasg/">
+ Security Portal</A>. It has fairly extensive coverage of IPsec.</P>
+<HR><A name="Smith"> Richard E Smith<CITE> Internet Cryptography</CITE>
+<BR></A> ISBN 0-201-92480-3, Addison Wesley, 1997
+<P>See the book's<A href="http://www.visi.com/crypto/inet-crypto/index.html">
+ home page</A></P>
+<HR><A name="neal"> Neal Stephenson<CITE> Cryptonomicon</CITE></A>
+<BR> Hardcover ISBN -380-97346-4, Avon, 1999.
+<P>A novel in which cryptography and the net figure prominently.<STRONG>
+ Highly recommended</STRONG>: I liked it enough I immediately went out
+ and bought all the author's other books.</P>
+<P>There is also a paperback edition. Sequels are expected.</P>
+<HR><A name="stevens"> Stevens and Wright</A><CITE> TCP/IP Illustrated</CITE>
+<BR> Addison-Wesley
+<UL>
+<LI>Vol. I: The Protocols 1994 ISBN:0-201-63346-9</LI>
+<LI>Vol. II: The Implementation 1995 ISBN:0-201-63354-X</LI>
+<LI>Vol. III: TCP for Transactions, HTTP, NNTP, and the UNIX Domain
+ Protocols 1996 ISBN: 0-201-63495-3</LI>
+</UL>
+<P>If you need to deal with the details of the network protocols, read
+ either this series or the<A href="#comer"> Comer</A> series before you
+ start reading the RFCs.</P>
+<HR><A name="Rubini"> Rubini</A><CITE> Linux Device Drivers</CITE>
+<BR> O'Reilly &amp; Associates, Inc. 1998 ISBN 1-56592-292-1
+<HR><A name="Zeigler"> Robert Zeigler</A><CITE> Linux Firewalls</CITE>
+<BR> Newriders Publishing, 2000 ISBN 0-7537-0900-9
+<P>A good book, with detailed coverage of ipchains(8) firewalls and of
+ many related issues.</P>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="glossary.html">Previous</A>
+<A HREF="rfc.html">Next</A>
+</BODY>
+</HTML>
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+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
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+<A HREF="interop.html">Next</A>
+<HR>
+<H1><A name="compat">Linux FreeS/WAN Compatibility Guide</A></H1>
+<P>Much of this document is quoted directly from the Linux FreeS/WAN<A href="mail.html">
+ mailing list</A>. Thanks very much to the community of testers,
+ patchers and commenters there, especially the ones quoted below but
+ also various contributors we haven't quoted.</P>
+<H2><A name="spec">Implemented parts of the IPsec Specification</A></H2>
+<P>In general, do not expect Linux FreeS/WAN to do everything yet. This
+ is a work-in-progress and some parts of the IPsec specification are not
+ yet implemented.</P>
+<H3><A name="in">In Linux FreeS/WAN</A></H3>
+<P>Things we do, as of version 1.96:</P>
+<UL>
+<LI>key management methods
+<DL>
+<DT>manually keyed</DT>
+<DD>using keys stored in /etc/ipsec.conf</DD>
+<DT>automatically keyed</DT>
+<DD>Automatically negotiating session keys as required. All connections
+ are automatically re-keyed periodically. The<A href="glossary.html#Pluto">
+ Pluto</A> daemon implements this using the<A href="glossary.html#IKE">
+ IKE</A> protocol.</DD>
+</DL>
+</LI>
+<LI>Methods of authenticating gateways for IKE
+<DL>
+<DT>shared secrets</DT>
+<DD>stored in<A href="manpage.d/ipsec.secrets.5.html"> ipsec.secrets(5)</A>
+</DD>
+<DT><A href="glossary.html#RSA">RSA</A> signatures</DT>
+<DD>For details, see<A href="manpage.d/ipsec_pluto.8.html"> pluto(8)</A>
+.</DD>
+<DT>looking up RSA authentication keys from<A href="glossary.html#DNS">
+ DNS</A>.</DT>
+<DD>Note that this technique cannot be fully secure until<A href="glossary.html#SDNS">
+ secure DNS</A> is widely deployed.</DD>
+</DL>
+</LI>
+<LI>groups for<A href="glossary.html#DH"> Diffie-Hellman</A> key
+ negotiation
+<DL>
+<DT>group 2, modp 1024-bit</DT>
+<DT>group 5, modp 1536-bit</DT>
+<DD>We implement these two groups.
+<P>In negotiating a keying connection (ISAKMP SA, Phase 1) we propose
+ both groups when we are the initiator, and accept either when a peer
+ proposes them. Once the keying connection is made, we propose only the
+ alternative agreed there for data connections (IPsec SA's, Phase 2)
+ negotiated over that keying connection.</P>
+</DD>
+</DL>
+</LI>
+<LI>encryption transforms
+<DL>
+<DT><A href="glossary.html#DES">DES</A></DT>
+<DD>DES is in the source code since it is needed to implement 3DES, but
+ single DES is not made available to users because<A href="politics.html#desnotsecure">
+ DES is insecure</A>.</DD>
+<DT><A href="glossary.html#3DES">Triple DES</A></DT>
+<DD>implemented, and used as the default encryption in Linux FreeS/WAN.</DD>
+</DL>
+</LI>
+<LI>authentication transforms
+<DL>
+<DT><A href="glossary.html#HMAC">HMAC</A> using<A href="glossary.html#MD5">
+ MD5</A></DT>
+<DD>implemented, may be used in IKE or by by AH or ESP transforms.</DD>
+<DT><A href="glossary.html#HMAC">HMAC</A> using<A href="glossary.html#SHA">
+ SHA</A></DT>
+<DD>implemented, may be used in IKE or by AH or ESP transforms.</DD>
+</DL>
+<P>In negotiations, we propose both of these and accept either.</P>
+</LI>
+<LI>compression transforms
+<DL>
+<DT>IPComp</DT>
+<DD>IPComp as described in RFC 2393 was added for FreeS/WAN 1.6. Note
+ that Pluto becomes confused if you ask it to do IPComp when the kernel
+ cannot.</DD>
+</DL>
+</LI>
+</UL>
+<P>All combinations of implemented transforms are supported. Note that
+ some form of packet-level<STRONG> authentication is required whenever
+ encryption is used</STRONG>. Without it, the encryption will not be
+ secure.</P>
+<H3><A name="dropped">Deliberately omitted</A></H3>
+ We do not implement everything in the RFCs because some of those things
+ are insecure. See our discussions of avoiding<A href="politics.html#weak">
+ bogus security</A>.
+<P>Things we deliberately omit which are required in the RFCs are:</P>
+<UL>
+<LI>null encryption (to use ESP as an authentication-only service)</LI>
+<LI>single DES</LI>
+<LI>DH group 1, a 768-bit modp group</LI>
+</UL>
+<P>Since these are the only encryption algorithms and DH group the RFCs
+ require, it is possible in theory to have a standards-conforming
+ implementation which will not interpoperate with FreeS/WAN. Such an
+ implementation would be inherently insecure, so we do not consider this
+ a problem.</P>
+<P>Anyway, most implementations sensibly include more secure options as
+ well, so dropping null encryption, single DES and Group 1 does not
+ greatly hinder interoperation in practice.</P>
+<P>We also do not implement some optional features allowed by the RFCs:</P>
+<UL>
+<LI>aggressive mode for negotiation of the keying channel or ISAKMP SA.
+ This mode is a little faster than main mode, but exposes more
+ information to an eavesdropper.</LI>
+</UL>
+<P>In theory, this should cause no interoperation problems since all
+ implementations are required to support the more secure main mode,
+ whether or not they also allow aggressive mode.</P>
+<P>In practice, it does sometimes produce problems with implementations
+ such as Windows 2000 where aggressive mode is the default. Typically,
+ these are easily solved with a configuration change that overrides that
+ default.</P>
+<H3><A name="not">Not (yet) in Linux FreeS/WAN</A></H3>
+<P>Things we don't yet do, as of version 1.96:</P>
+<UL>
+<LI>key management methods
+<UL>
+<LI>authenticate key negotiations via local<A href="glossary.html#PKI">
+ PKI</A> server, but see links to user<A href="web.html#patch"> patches</A>
+</LI>
+<LI>authenticate key negotiations via<A href="glossary.html#SDNS">
+ secure DNS</A></LI>
+<LI>unauthenticated key management, using<A href="glossary.html#DH">
+ Diffie-Hellman</A> key agreement protocol without authentication.
+ Arguably, this would be worth doing since it is secure against all
+ passive attacks. On the other hand, it is vulnerable to an active<A href="glossary.html#middle">
+ man-in-the-middle attack</A>.</LI>
+</UL>
+</LI>
+<LI>encryption transforms
+<P>Currently<A href="glossary.html#3DES"> Triple DES</A> is the only
+ encryption method Pluto will negotiate.</P>
+<P>No additional encryption transforms are implemented, though the RFCs
+ allow them and some other IPsec implementations support various of
+ them. We are not eager to add more. See this<A href="faq.html#other.cipher">
+ FAQ question</A>.</P>
+<P><A href="glossary.html#AES">AES</A>, the successor to the DES
+ standard, is an excellent candidate for inclusion in FreeS/WAN, see
+ links to user<A href="web.html#patch"> patches</A>.</P>
+</LI>
+<LI>authentication transforms
+<P>No optional additional authentication transforms are currently
+ implemented. Likely<A href="glossary.html#SHA-256"> SHA-256, SHA-384
+ and SHA-512</A> will be added when AES is.</P>
+</LI>
+<LI>Policy checking on decrypted packets
+<P>To fully comply with the RFCs, it is not enough just to accept only
+ packets which survive any firewall rules in place to limit what IPsec
+ packets get in, and then pass KLIPS authentication. That is what
+ FreeS/WAN currently does.</P>
+<P>We should also apply additional tests, for example ensuring that all
+ packets emerging from a particular tunnel have source and destination
+ addresses that fall within the subnets defined for that tunnel, and
+ that packets with those addresses that did not emerge from the
+ appropriate tunnel are disallowed.</P>
+<P>This will be done as part of a KLIPS rewrite. See these<A href="intro.html#applied">
+ links</A> and the<A href="mail.html"> design mailing list</A> for
+ discussion.</P>
+</LI>
+</UL>
+<H2><A name="pfkey">Our PF-Key implementation</A></H2>
+<P>We use PF-key Version Two for communication between the KLIPS kernel
+ code and the Pluto Daemon. PF-Key v2 is defined by<A href="http://www.normos.org/ietf/rfc/rfc2367.txt">
+ RFC 2367</A>.</P>
+<P>The &quot;PF&quot; stands for Protocol Family. PF-Inet defines a
+ kernel/userspace interface for the TCP/IP Internet protocols (TCP/IP),
+ and other members of the PF series handle Netware, Appletalk, etc.
+ PF-Key is just a PF for key-related matters.</P>
+<H3><A name="pfk.port">PF-Key portability</A></H3>
+<P>PF-Key came out of Berkeley Unix work and is used in the various BSD
+ IPsec implementations, and in Solaris. This means there is some hope of
+ porting our Pluto(8) to one of the BSD distributions, or of running
+ their photurisd(8) on Linux if you prefer<A href="glossary.html#photuris">
+ Photuris</A> key management over IKE.</P>
+<P>It is, however, more complex than that. The PK-Key RFC deliberately
+ deals only with keying, not policy management. The three PF-Key
+ implementations we have looked at -- ours, OpenBSD and KAME -- all have
+ extensions to deal with security policy, and the extensions are
+ different. There have been discussions aimed at sorting out the
+ differences, perhaps for a version three PF-Key spec. All players are
+ in favour of this, but everyone involved is busy and it is not clear
+ whether or when these discussions might bear fruit.</P>
+<H2><A name="otherk">Kernels other than the latest 2.2.x and 2.4.y</A></H2>
+<P>We develop and test on Redhat Linux using the most recent kernel in
+ the 2.2 and 2.4 series. In general, we recommend you use the latest
+ kernel in one of those series. Complications and caveats are discussed
+ below.</P>
+<H3><A name="kernel.2.0">2.0.x kernels</A></H3>
+<P>Consider upgrading to the 2.2 kernel series. If you want to stay with
+ the 2.0 series, then we strongly recommend 2.0.39. Some useful security
+ patches were added in 2.0.38.</P>
+<P>Various versions of the code have run at various times on most 2.0.xx
+ kernels, but the current version is only lightly tested on 2.0.39, and
+ not at all on older kernels.</P>
+<P>Some of our patches for older kernels are shipped in 2.0.37 and
+ later, so they are no longer provided in FreeS/WAN. This means recent
+ versions of FreeS/WAN will probably not compile on anything earlier
+ than 2.0.37.</P>
+<H3><A name="kernel.production">2.2 and 2.4 kernels</A></H3>
+<DL>
+<DT>FreeS/WAN 1.0</DT>
+<DD>ran only on 2.0 kernels</DD>
+<DT>FreeS/WAN 1.1 to 1.8</DT>
+<DD>ran on 2.0 or 2.2 kernels
+<BR> ran on some development kernels, 2.3 or 2.4-test</DD>
+<DT>FreeS/WAN 1.9 to 1.96</DT>
+<DD>runs on 2.0, 2.2 or 2.4 kernels</DD>
+</DL>
+<P>In general,<STRONG> we suggest the latest 2.2 kernel or 2.4 for
+ production use</STRONG>.</P>
+<P>Of course no release can be guaranteed to run on kernels more recent
+ than it is, so quite often there will be no stable FreeS/WAN for the
+ absolute latest kernel. See the<A href="faq.html#k.versions"> FAQ</A>
+ for discussion.</P>
+<H2><A name="otherdist">Intel Linux distributions other than Redhat</A></H2>
+<P>We develop and test on Redhat 6.1 for 2.2 kernels, and on Redhat 7.1
+ or 7.2 for 2.4, so minor changes may be required for other
+ distributions.</P>
+<H3><A name="rh7">Redhat 7.0</A></H3>
+<P>There are some problems with FreeS/WAN on Redhat 7.0. They are
+ soluble, but we recommend you upgrade to a later Redhat instead..</P>
+<P>Redhat 7 ships with two compilers.</P>
+<UL>
+<LI>Their<VAR> gcc</VAR> is version 2.96. Various people, including the
+ GNU compiler developers and Linus, have said fairly emphatically that
+ using this was a mistake. 2.96 is a development version, not intended
+ for production use. In particular, it will not compile a Linux kernel.</LI>
+<LI>Redhat therefore also ship a separate compiler, which they call<VAR>
+ kgcc</VAR>, for compiling kernels.</LI>
+</UL>
+<P>Kernel Makefiles have<VAR> gcc</VAR> as a default, and must be
+ adjusted to use<VAR> kgcc</VAR> before a kernel will compile on 7.0.
+ This mailing list message gives details:</P>
+<PRE>Subject: Re: AW: Installing IPsec on Redhat 7.0
+   Date: Thu, 1 Feb 2001 14:32:52 -0200 (BRST)
+  From: Mads Rasmussen &lt;mads@cit.com.br&gt;
+ 
+&gt; From www.redhat.com/support/docs/gotchas/7.0/gotchas-7-6.html#ss6.1
+
+cd to /usr/src/linux and open the Makefile in your favorite editor. You
+will need to look for a line similar to this:
+
+CC = $(CROSS_COMPILE)gcc -D__KERNEL__ -I$(HPATH)
+
+This line specifies which C compiler to use to build the kernel. It should
+be changed to:
+
+CC = $(CROSS_COMPILE)kgcc -D__KERNEL__ -I$(HPATH)
+
+for Red Hat Linux 7. The kgcc compiler is egcs 2.91.66. From here you can
+proceed with the typical compiling steps.</PRE>
+<P>Check the<A href="mail.html"> mailing list</A> archive for more
+ recent news.</P>
+<H3><A name="suse">SuSE Linux</A></H3>
+<P>SuSE 6.3 and later versions, at least in Europe, ship with FreeS/WAN
+ included.</P>
+<P>FreeS/WAN packages distributed for SuSE 7.0-7.2 were somehow
+ miscompiled. You can find fixed packages on<A HREF="http://www.suse.de/~garloff/linux/FreeSWAN">
+ Kurt Garloff's page</A>.</P>
+<P>Here are some notes for an earlier SuSE version.</P>
+<H4>SuSE Linux 5.3</H4>
+<PRE>Date: Mon, 30 Nov 1998
+From: Peter Onion &lt;ponion@srd.bt.co.uk&gt;
+
+... I got Saturdays snapshot working between my two SUSE5.3 machines at home.
+
+The mods to the install process are quite simple.  From memory and looking at
+the files on the SUSE53 machine here at work....
+
+And extra link in each of the /etc/init.d/rc?.d directories called K35ipsec
+which SUSE use to shut a service down.
+
+A few mods in /etc/init.d/ipsec  to cope with the different places that SUSE
+put config info, and remove the inculsion of /etc/rc.d/init.d/functions and .
+/etc/sysconfig/network as they don't exists and 1st one isn't needed anyway.
+
+insert &quot;. /etc/rc.config&quot; to pick up the SUSE config info and use 
+
+  if test -n &quot;$NETCONFIG&quot; -a &quot;$NETCONFIG&quot; != &quot;YAST_ASK&quot; ; then
+
+to replace 
+
+  [ ${NETWORKING} = &quot;no&quot; ] &amp;&amp; exit 0
+
+Create /etc/sysconfig  as SUSE doesn't have one.
+
+I think that was all (but I prob forgot something)....</PRE>
+<P>You may also need to fiddle initialisation scripts to ensure that<VAR>
+ /var/run/pluto.pid</VAR> is removed when rebooting. If this file is
+ present, Pluto does not come up correctly.</P>
+<H3><A name="slack">Slackware</A></H3>
+<PRE>Subject: Re: linux-IPsec: Slackware distribution
+  Date:  Thu, 15 Apr 1999 12:07:01 -0700
+  From:  Evan Brewer &lt;dmessiah@silcon.com&gt;
+
+&gt; Very shortly, I will be needing to install IPsec on at least gateways that
+&gt; are running Slackware. . . .
+
+The only trick to getting it up is that on the slackware dist there is no
+init.d directory in /etc/rc.d .. so create one.  Then, what I do is take the
+IPsec startup script which normally gets put into the init.d directory, and
+put it in /etc/rc.d and name ir rc.ipsec .. then I symlink it to the file
+in init.d.  The only file in the dist you need to really edit is the
+utils/Makefile, setup4:
+
+Everything else should be just fine.</PRE>
+<P>A year or so later:</P>
+<PRE>Subject: Re: HTML Docs- Need some cleanup?
+   Date: Mon, 8 Jan 2001
+   From: Jody McIntyre &lt;jodym@oeone.com&gt;
+
+I have successfully installed FreeS/WAN on several Slackware 7.1 machines.
+FreeS/WAN installed its rc.ipsec file in /etc/rc.d.  I had to manually call
+this script from rc.inet2.  This seems to be an easier method than Evan
+Brewer's.</PRE>
+<H3><A name="deb">Debian</A></H3>
+<P>A recent (Nov 2001) mailing list points to a<A href="http://www.thing.dyndns.org/debian/vpn.htm">
+ web page</A> on setting up several types of tunnel, including IPsec, on
+ Debian.</P>
+<P>Some older information:</P>
+<PRE>Subject: FreeS/WAN 1.0 on Debian 2.1
+   Date: Tue, 20 Apr 1999
+  From:  Tim Miller &lt;cerebus+counterpane@haybaler.sackheads.org&gt;
+
+        Compiled and installed without error on a Debian 2.1 system
+with kernel-source-2.0.36 after pointing RCDIR in utils/Makefile to
+/etc/init.d.
+
+        /var/lock/subsys/ doesn't exist on Debian boxen, needs to be
+created; not a fatal error.
+
+        Finally, IPsec scripts appear to be dependant on GNU awk
+(gawk); the default Debian awk (mawk-1.3.3-2) had fatal difficulties.
+With gawk installed and /etc/alternatives/awk linked to /usr/bin/gawk
+operation appears flawless.</PRE>
+<P>The scripts in question have been modified since this was posted. Awk
+ versions should no longer be a problem.</P>
+<H3><A name="caldera">Caldera</A></H3>
+<PRE>Subject: Re: HTML Docs- Need some cleanup?
+   Date: Mon, 08 Jan 2001
+   From: Andy Bradford &lt;andyb@calderasystems.com&gt;
+
+On Sun, 07 Jan 2001 22:59:05 EST, Sandy Harris wrote:
+
+&gt;     Intel Linux distributions other than Redhat 5.x and 6.x 
+&gt;         Redhat 7.0 
+&gt;         SuSE Linux 
+&gt;             SuSE Linux 5.3 
+&gt;         Slackware 
+&gt;         Debian 
+
+Can you please include Caldera in this list?  I have tested it since 
+FreeS/Wan 1.1 and it works great with our systems---provided one 
+follows the FreeS/Wan documentation. :-)
+
+Thank you,
+Andy</PRE>
+<H2><A name="CPUs">CPUs other than Intel</A></H2>
+<P>FreeS/WAN has been run sucessfully on a number of different CPU
+ architectures. If you have tried it on one not listed here, please post
+ to the<A href="mail.html"> mailing list</A>.</P>
+<H3><A name=" strongarm">Corel Netwinder (StrongARM CPU)</A></H3>
+<PRE>Subject: linux-ipsec: Netwinder diffs
+Date: Wed, 06 Jan 1999
+From: rhatfield@plaintree.com
+
+I had a mistake in my IPsec-auto, so I got things working this morning.
+
+Following are the diffs for my changes.  Probably not the best and cleanest way 
+of doing it, but it works. . . . </PRE>
+<P>These diffs are in the 0.92 and later distributions, so these should
+ work out-of-the-box on Netwinder.</P>
+<H3><A name="yellowdog">Yellow Dog Linux on Power PC</A></H3>
+<PRE>Subject:  Compiling FreeS/WAN 1.1 on YellowDog Linux (PPC)
+   Date:  11 Dec 1999
+   From:  Darron Froese &lt;darron@fudgehead.com&gt;
+
+I'm summarizing here for the record - because it's taken me many hours to do
+this (multiple times) and because I want to see IPsec on more linuxes than
+just x86.
+
+Also, I can't remember if I actually did summarize it before... ;-) I'm
+working too many late hours.
+
+That said - here goes.
+
+1. Get your linux kernel and unpack into /usr/src/linux/ - I used 2.2.13.
+&lt;http://www.kernel.org/pub/linux/kernel/v2.2/linux-2.2.13.tar.bz2&gt;
+
+2. Get FreeS/WAN and unpack into /usr/src/freeswan-1.1
+&lt;ftp://ftp.xs4all.nl/pub/crypto/freeswan/freeswan-1.1.tar.gz&gt;
+
+3. Get the gmp src rpm from here:
+&lt;ftp://ftp.yellowdoglinux.com//pub/yellowdog/champion-1.1/SRPMS/SRPMS/gmp-2.0.2-9a.src.rpm&gt;
+
+4. Su to root and do this: rpm --rebuild gmp-2.0.2-9a.src.rpm
+
+You will see a lot of text fly by and when you start to see the rpm
+recompiling like this:
+
+Executing: %build
++ umask 022
++ cd /usr/src/redhat/BUILD
++ cd gmp-2.0.2
++ libtoolize --copy --force
+Remember to add `AM_PROG_LIBTOOL' to `configure.in'.
+You should add the contents of `/usr/share/aclocal/libtool.m4' to
+`aclocal.m4'.
++ CFLAGS=-O2 -fsigned-char
++ ./configure --prefix=/usr
+
+Hit Control-C to stop the rebuild. NOTE: We're doing this because for some
+reason the gmp source provided with FreeS/WAN 1.1 won't build properly on
+ydl.
+
+cd /usr/src/redhat/BUILD/
+cp -ar gmp-2.0.2 /usr/src/freeswan-1.1/
+cd /usr/src/freeswan-1.1/
+rm -rf gmp
+mv gmp-2.0.2 gmp
+
+5. Open the freeswan Makefile and change the line that says:
+KERNEL=$(b)zimage (or something like that) to
+KERNEL=vmlinux
+
+6. cd ../linux/
+
+7. make menuconfig
+Select an option or two and then exit - saving your changes.
+
+8. cd ../freeswan-1.1/ ; make menugo
+
+That will start the whole process going - once that's finished compiling,
+you have to install your new kernel and reboot.
+
+That should build FreeS/WAN on ydl (I tried it on 1.1).</PRE>
+ And a later message on the same topic:
+<PRE>Subject: Re: FreeS/WAN, PGPnet and E-mail
+   Date: Sat, 22 Jan 2000
+   From: Darron Froese &lt;darron@fudgehead.com&gt;
+
+on 1/22/00 6:47 PM, Philip Trauring at philip@trauring.com wrote:
+
+&gt; I have a PowerMac G3 ...
+
+The PowerMac G3 can run YDL 1.1 just fine. It should also be able to run
+FreeS/WAN 1.2patch1 with a couple minor modifications:
+
+1. In the Makefile it specifies a bzimage for the kernel compile - you have
+to change that to vmlinux for the PPC.
+
+2. The gmp source that comes with FreeS/WAN (for whatever reason) fails to
+compile. I have gotten around this by getting the gmp src rpm from here:
+
+ftp://ftp.yellowdoglinux.com//pub/yellowdog/champion-1.1/SRPMS/SRPMS/gmp-2.0.2-9a.src.rpm
+
+If you rip the source out of there - and place it where the gmp source
+resides it will compile just fine.</PRE>
+<P>FreeS/WAN no longer includes GMP source.</P>
+<H3><A name="mklinux">Mklinux</A></H3>
+<P>One user reports success on the Mach-based<STRONG> m</STRONG>icro<STRONG>
+k</STRONG>ernel Linux.</P>
+<PRE>Subject: Smiles on sparc and ppc
+   Date: Fri, 10 Mar 2000
+   From: Jake Hill &lt;jah@alien.bt.co.uk&gt;
+
+You may or may not be interested to know that I have successfully built
+FreeS/WAN on a number of non intel alpha architectures; namely on ppc
+and sparc and also on osfmach3/ppc (MkLinux). I can report that it just
+works, mostly, with few changes.</PRE>
+<H3><A name="alpha">Alpha 64-bit processors</A></H3>
+<PRE>Subject: IT WORKS (again) between intel &amp; alpha :-)))))
+   Date: Fri, 29 Jan 1999
+   From: Peter Onion &lt;ponion@srd.bt.co.uk&gt;
+
+Well I'm happy to report that I've got an IPsec connection between by intel &amp; alpha machines again :-))
+
+If you look back on this list to 7th of December I wrote...
+
+-On 07-Dec-98 Peter Onion wrote:
+-&gt; 
+-&gt; I've about had enuf of wandering around inside the kernel trying to find out
+-&gt; just what is corrupting outgoing packets...
+-
+-Its 7:30 in the evening .....
+-
+-I FIXED IT  :-))))))))))))))))))))))))))))))))
+-
+-It was my own fault :-((((((((((((((((((
+-
+-If you ask me very nicly I'll tell you where I was a little too over keen to
+-change unsigned long int __u32 :-)  OPSE ...
+-
+-So tomorrow it will full steam ahead to produce a set of diffs/patches against
+-0.91 
+-
+-Peter Onion.</PRE>
+<P>In general (there have been some glitches), FreeS/WAN has been
+ running on Alphas since then.</P>
+<H3><A name="SPARC">Sun SPARC processors</A></H3>
+<P>Several users have reported success with FreeS/WAN on SPARC Linux.
+ Here is one mailing list message:</P>
+<PRE>Subject: Smiles on sparc and ppc
+   Date: Fri, 10 Mar 2000
+   From: Jake Hill &lt;jah@alien.bt.co.uk&gt;
+
+You may or may not be interested to know that I have successfully built
+FreeS/WAN on a number of non intel alpha architectures; namely on ppc
+and sparc and also on osfmach3/ppc (MkLinux). I can report that it just
+works, mostly, with few changes.
+
+I have a question, before I make up some patches. I need to hack
+gmp/mpn/powerpc32/*.s to build them. Is this ok? The changes are
+trivial, but could I also use a different version of gmp? Is it vanilla
+here?
+
+I guess my only real headache is from ipchains, which appears to stop
+running when IPsec has been started for a while. This is with 2.2.14 on
+sparc.</PRE>
+<P>This message, from a different mailing list, may be relevant for
+ anyone working with FreeS/WAN on Suns:</P>
+<PRE>Subject: UltraSPARC DES assembler
+   Date: Thu, 13 Apr 2000
+   From: svolaf@inet.uni2.dk (Svend Olaf Mikkelsen)
+     To: coderpunks@toad.com
+
+An UltraSPARC assembler version of the LibDES/SSLeay/OpenSSL des_enc.c
+file is available at http://inet.uni2.dk/~svolaf/des.htm.
+
+This brings DES on UltraSPARC from slower than Pentium at the same
+clock speed to significantly faster.</PRE>
+<H3><A name="mips">MIPS processors</A></H3>
+<P>We know FreeS/WAN runs on at least some MIPS processors because<A href="http://www.lasat.com">
+ Lasat</A> manufacture an IPsec box based on an embedded MIPS running
+ Linux with FreeS/WAN. We have no details.</P>
+<H3><A name="crusoe">Transmeta Crusoe</A></H3>
+<P>The Merilus<A href="http://www.merilus.com/products/fc/index.shtml">
+ Firecard</A>, a Linux firewall on a PCI card, is based on a Crusoe
+ processor and supports FreeS/WAN.</P>
+<H3><A name="coldfire">Motorola Coldfire</A></H3>
+<PRE>Subject: Re: Crypto hardware support
+   Date: Mon, 03 Jul 2000
+   From: Dan DeVault &lt;devault@tampabay.rr.com&gt;
+
+.... I have been running
+uClinux with FreeS/WAN 1.4 on a system built by Moreton Bay  (
+http://www.moretonbay.com )  and it was using a Coldfire processor
+and was able to do the Triple DES encryption at just about
+1 mbit / sec rate.......  they put a Hi/Fn 7901 hardware encryption
+chip on their board and now their system does over 25 mbit of 3DES
+encryption........ pretty significant increase if you ask me.</PRE>
+<H2><A name="multiprocessor">Multiprocessor machines</A></H2>
+<P>FreeS/WAN is designed to work on SMP (symmetric multi-processing)
+ Linux machines and is regularly tested on dual processor x86 machines.</P>
+<P>We do not know of any testing on multi-processor machines with other
+ CPU architectures or with more than two CPUs. Anyone who does test
+ this, please report results to the<A href="mail.html"> mailing list</A>
+.</P>
+<P>The current design does not make particularly efficient use of
+ multiprocessor machines; some of the kernel work is single-threaded.</P>
+<H2><A name="hardware">Support for crypto hardware</A></H2>
+<P>Supporting hardware cryptography accelerators has not been a high
+ priority for the development team because it raises a number of fairly
+ complex issues:</P>
+<UL>
+<LI>Can you trust the hardware? If it is not Open Source, how do you
+ audit its security? Even if it is, how do you check that the design has
+ no concealed traps?</LI>
+<LI>If an interface is added for such hardware, can that interface be
+ subverted or misused?</LI>
+<LI>Is hardware acceleration actually a performance win? It clearly is
+ in many cases, but on a fast machine it might be better to use the CPU
+ for the encryption than to pay the overheads of moving data to and from
+ a crypto board.</LI>
+<LI>the current KLIPS code does not provide a clean interface for
+ hardware accelerators</LI>
+</UL>
+<P>That said, we have a<A href="#coldfire"> report</A> of FreeS/WAN
+ working with one crypto accelerator and some work is going on to modify
+ KLIPS to create a clean generic interface to such products. See this<A href="http://www.jukie.net/~bart/linux-ipsec/">
+ web page</A> for some of the design discussion.</P>
+<P>More recently, a patch to support some hardware accelerators has been
+ posted:</P>
+<PRE>Subject: [Design] [PATCH] H/W acceleration patch
+   Date: Tue, 18 Sep 2001
+   From: &quot;Martin Gadbois&quot; &lt;martin.gadbois@colubris.com&gt;
+ 
+Finally!!
+Here's a web site with H/W acceleration patch for FreeS/WAN 1.91, including
+S/W and Hifn 7901 crypto support.
+
+http://sources.colubris.com/
+
+Martin Gadbois</PRE>
+<P>Hardware accelerators could take performance well beyond what
+ FreeS/WAN can do in software (discussed<A href="performance.html"> here</A>
+). Here is some discussion off the IETF IPsec list, October 2001:</P>
+<PRE> ... Currently shipping chips deliver, 600 mbps throughput on a single
+ stream of 3DES IPsec traffic.  There are also chips that use multiple
+ cores to do 2.4 gbps.  We (Cavium) and others have announced even faster
+ chips. ... Mid 2002 versions will handle at line rate (OC48 and OC192)
+ IPsec and SSL/TLS traffic not only 3DES CBC but also AES and arc4.</PRE>
+<P>The patches to date support chips that have been in production for
+ some time, not the state-of-the-art latest-and-greatest devices
+ described in that post. However, they may still outperform software and
+ they almost certainly reduce CPU overhead.</P>
+<H2><A name="ipv6">IP version 6 (IPng)</A></H2>
+<P>The Internet currently runs on version four of the IP protocols. IPv4
+ is what is in the standard Linux IP stack, and what FreeS/WAN was built
+ for. In IPv4, IPsec is an optional feature.</P>
+<P>The next version of the IP protocol suite is version six, usually
+ abbreviated either as &quot;IPv6&quot; or as &quot;IPng&quot; for &quot;IP: the next
+ generation&quot;. For IPv6, IPsec is a required feature. Any machine doing
+ IPv6 is required to support IPsec, much as any machine doing (any
+ version of) IP is required to support ICMP.</P>
+<P>There is a Linux implementation of IPv6 in Linux kernels 2.2 and
+ above. For details, see the<A href="http://www.cs-ipv6.lancs.ac.uk/ipv6/systems/linux/faq/">
+ FAQ</A>. It does not yet support IPsec. The<A href="http://www.linux-ipv6.org/">
+ USAGI</A> project are also working on IPv6 for Linux.</P>
+<P>FreeS/WAN was originally built for the current standard, IPv4, but we
+ are interested in seeing it work with IPv6. Some progress has been
+ made, and a patched version with IPv6 support is<A href="http://www.ipv6.iabg.de/downloadframe/index.html">
+ available</A>. For more recent information, check the<A href="mail.html">
+ mailing list</A>.</P>
+<H3><A name="v6.back">IPv6 background</A></H3>
+<P>IPv6 has been specified by an IETF<A href="http://www.ietf.org/html.charters/ipngwg-charter.html">
+ working group</A>. The group's page lists over 30 RFCs to date, and
+ many Internet Drafts as well. The overview is<A href="http://www.ietf.org/rfc/rfc2460.txt">
+ RFC 2460</A>. Major features include:</P>
+<UL>
+<LI>expansion of the address space from 32 to 128 bits,</LI>
+<LI>changes to improve support for
+<UL>
+<LI>mobile IP</LI>
+<LI>automatic network configuration</LI>
+<LI>quality of service routing</LI>
+<LI>...</LI>
+</UL>
+</LI>
+<LI>improved security via IPsec</LI>
+</UL>
+<P>A number of projects are working on IPv6 implementation. A prominent
+ Open Source effort is<A href="http://www.kame.net/"> KAME</A>, a
+ collaboration among several large Japanese companies to implement IPv6
+ for Berkeley Unix. Other major players are also working on IPv6. For
+ example, see pages at:</P>
+<UL>
+<LI><A href="http://playground.sun.com/pub/ipng/html/ipng-main.html">Sun</A>
+</LI>
+<LI><A href="http://www.cisco.com/warp/public/732/ipv6/index.html">Cisco</A>
+</LI>
+<LI><A href="http://www.microsoft.com/windows2000/techinfo/howitworks/communications/networkbasics/IPv6.asp">
+Microsoft</A></LI>
+</UL>
+<P>The<A href="http://www.6bone.net/"> 6bone</A> (IPv6 backbone) testbed
+ network has been up for some time. There is an active<A href="http://www.ipv6.org/">
+ IPv6 user group</A>.</P>
+<P>One of the design goals for IPv6 was that it must be possible to
+ convert from v4 to v6 via a gradual transition process. Imagine the
+ mess if there were a &quot;flag day&quot; after which the entire Internet used
+ v6, and all software designed for v4 stopped working. Almost every
+ computer on the planet would need major software changes! There would
+ be huge costs to replace older equipment. Implementers would be worked
+ to death before &quot;the day&quot;, systems administrators and technical support
+ would be completely swamped after it. The bugs in every implementation
+ would all bite simultaneously. Large chunks of the net would almost
+ certainly be down for substantial time periods. ...</P>
+<P>Fortunately, the design avoids any &quot;flag day&quot;. It is therefore a
+ little tricky to tell how quickly IPv6 will take over. The transition
+ has certainly begun. For examples, see announcements from<A href="http://www.mailbase.ac.uk/lists/internet2/2000-03/0016.html">
+ NTT</A> and<A href="http://www.vnunet.com/News/1102383"> Nokia</A>.
+ However, it is not yet clear how quickly the process will gain
+ momentum, or when it will be completed. Likely large parts of the
+ Internet will remain with IPv4 for years to come.</P>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="trouble.html">Previous</A>
+<A HREF="interop.html">Next</A>
+</BODY>
+</HTML>
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
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+<A HREF="toc.html">Contents</A>
+<A HREF="install.html">Previous</A>
+<A HREF="background.html">Next</A>
+<HR>
+<H1><A NAME="config">How to configure FreeS/WAN</A></H1>
+<P>This page will teach you how to configure a simple network-to-network
+ link or a Road Warrior connection between two Linux FreeS/WAN boxes.</P>
+<P>See also these related documents:</P>
+<UL>
+<LI>our<A HREF="quickstart.html#quickstart"> quickstart</A> guide to<A HREF="glossary.html#carpediem">
+ opportunistic encryption</A></LI>
+<LI>our guide to configuration with<A HREF="policygroups.html#policygroups">
+ policy groups</A></LI>
+<LI>our<A HREF="adv_config.html#adv_config"> advanced configuration</A>
+ document</LI>
+</UL>
+<P> The network-to-network setup allows you to connect two office
+ networks into one Virtual Private Network, while the Road Warrior
+ connection secures a laptop's telecommute to work. Our examples also
+ show the basic procedure on the Linux FreeS/WAN side where another
+ IPsec peer is in play.</P>
+<P> Shortcut to<A HREF="#config.netnet"> net-to-net</A>.
+<BR> Shortcut to<A HREF="#config.rw"> Road Warrior</A>.</P>
+<H2><A NAME="16_1">Requirements</A></H2>
+<P>To configure the network-to-network connection you must have:</P>
+<UL>
+<LI>two Linux gateways with static IPs</LI>
+<LI>a network behind each gate. Networks must have non-overlapping IP
+ ranges.</LI>
+<LI>Linux FreeS/WAN<A HREF="install.html#install"> installed</A> on both
+ gateways</LI>
+<LI><A HREF="http://www.tcpdump.org"><VAR>tcpdump</VAR></A> on the local
+ gate, to test the connection</LI>
+</UL>
+<P>For the Road Warrior you need:</P>
+<UL>
+<LI>one Linux box with a static IP</LI>
+<LI>a Linux laptop with a dynamic IP</LI>
+<LI>Linux FreeS/WAN installed on both</LI>
+<LI>for testing,<VAR> tcpdump</VAR> on your gateway or laptop</LI>
+</UL>
+<P>If both IPs are dynamic, your situation is a bit trickier. Your best
+ bet is a variation on the<A HREF="#config.rw"> Road Warrior</A>, as
+ described in<A HREF="http://lists.freeswan.org/archives/users/2003-October/msg00282.html">
+ this mailing list message</A>.</P>
+<H2><A name="config.netnet"></A>Net-to-Net connection</H2>
+<H3><A name="netnet.info.ex">Gather information</A></H3>
+<P>For each gateway, compile the following information:</P>
+<UL>
+<LI>gateway IP</LI>
+<LI>IP range of the subnet you will be protecting. This doesn't have to
+ be your whole physical subnet.</LI>
+<LI>a name by which that gateway can identify itself for IPsec
+ negotiations. Its form is a Fully Qualified Domain Name preceded by an
+ @ sign, ie. @xy.example.com.
+<BR> It does not need to be within a domain that you own. It can be a
+ made-up name.</LI>
+</UL>
+<H4>Get your leftrsasigkey</H4>
+<P>On your local Linux FreeS/WAN gateway, print your IPsec public key:</P>
+<PRE>    ipsec showhostkey --left</PRE>
+<P>The output should look like this (with the key shortened for easy
+ reading):</P>
+<PRE>    # RSA 2048 bits   xy.example.com   Fri Apr 26 15:01:41 2002
+    leftrsasigkey=0sAQOnwiBPt...</PRE>
+<P>Don't have a key? Use<A HREF="manpage.d/ipsec_newhostkey.8.html"><VAR>
+ ipsec newhostkey</VAR></A> to create one.</P>
+<H4>...and your rightrsasigkey</H4>
+<P>Get a console on the remote side:</P>
+<PRE>    ssh2 ab.example.com</PRE>
+<P>In that window, type:</P>
+<PRE>    ipsec showhostkey --right</PRE>
+<P>You'll see something like:</P>
+<PRE>    # RSA 2192 bits   ab.example.com   Thu May 16 15:26:20 2002
+    rightrsasigkey=0sAQOqH55O...</PRE>
+<H3><A NAME="16_2_2">Edit<VAR> /etc/ipsec.conf</VAR></A></H3>
+<P>Back on the local gate, copy our template to<VAR> /etc/ipsec.conf</VAR>
+. (on Mandrake,<VAR> /etc/freeswan/ipsec.conf</VAR>). Substitute the
+ information you've gathered for our example data.</P>
+<PRE>conn net-to-net
+    left=192.0.2.2                 # Local vitals
+    leftsubnet=192.0.2.128/29      # 
+    leftid=@xy.example.com         #   
+    leftrsasigkey=0s1LgR7/oUM...   #
+    leftnexthop=%defaultroute      # correct in many situations 
+    right=192.0.2.9                # Remote vitals
+    rightsubnet=10.0.0.0/24        #
+    rightid=@ab.example.com        # 
+    rightrsasigkey=0sAQOqH55O...   #
+    rightnexthop=%defaultroute     # correct in many situations
+    auto=add                       # authorizes but doesn't start this 
+                                   # connection at startup</PRE>
+<P> &quot;Left&quot; and &quot;right&quot; should represent the machines that have FreeS/WAN
+ installed on them, and &quot;leftsubnet&quot; and &quot;rightsubnet&quot; machines that are
+ being protected. /32 is assumed for left/right and left/rightsubnet
+ parameters.</P>
+<P>Copy<VAR> conn net-to-net</VAR> to the remote-side /etc/ipsec.conf.
+ If you've made no other modifications to either<VAR> ipsec.conf</VAR>,
+ simply:</P>
+<PRE>    scp2 ipsec.conf root@ab.example.com:/etc/ipsec.conf</PRE>
+<H3><A NAME="16_2_3">Start your connection</A></H3>
+<P>Locally, type:</P>
+<PRE>    ipsec auto --up net-to-net</PRE>
+<P>You should see:</P>
+<PRE>    104 &quot;net-net&quot; #223: STATE_MAIN_I1: initiate
+    106 &quot;net-net&quot; #223: STATE_MAIN_I2: sent MI2, expecting MR2
+    108 &quot;net-net&quot; #223: STATE_MAIN_I3: sent MI3, expecting MR3
+    004 &quot;net-net&quot; #223: STATE_MAIN_I4: ISAKMP SA established
+    112 &quot;net-net&quot; #224: STATE_QUICK_I1: initiate
+    004 &quot;net-net&quot; #224: STATE_QUICK_I2: sent QI2, IPsec SA established</PRE>
+<P>The important thing is<VAR> IPsec SA established</VAR>. If you're
+ unsuccessful, see our<A HREF="trouble.html#trouble"> troubleshooting
+ tips</A>.</P>
+<H3><A NAME="16_2_4">Do not MASQ or NAT packets to be tunneled</A></H3>
+<P>If you are using<A HREF="glossary.html#masq"> IP masquerade</A> or<A HREF="glossary.html#NAT.gloss">
+ Network Address Translation (NAT)</A> on either gateway, you must now
+ exempt the packets you wish to tunnel from this treatment. For example,
+ if you have a rule like:</P>
+<PRE>iptables -t nat -A POSTROUTING -o eth0 -s 10.0.0.0/24 -j MASQUERADE
+</PRE>
+<P>change it to something like:</P>
+<PRE>iptables -t nat -A POSTROUTING -o eth0 -s 10.0.0.0/24 -d \! 192.0.2.128/29 -j MASQUERADE</PRE>
+<P>This may be necessary on both gateways.</P>
+<H3><A NAME="16_2_5">Test your connection</A></H3>
+<P>Sit at one of your local subnet nodes (not the gateway), and ping a
+ subnet node on the other (again, not the gateway).</P>
+<PRE>    ping fileserver.toledo.example.com</PRE>
+<P>While still pinging, go to the local gateway and snoop your outgoing
+ interface, for example:</P>
+<PRE>    tcpdump -i ppp0</PRE>
+<P>You want to see ESP (Encapsulating Security Payload) packets moving<B>
+ back and forth</B> between the two gateways at the same frequency as
+ your pings:</P>
+<PRE>    19:16:32.046220 192.0.2.2 &gt; 192.0.2.9: ESP(spi=0x3be6c4dc,seq=0x3)
+    19:16:32.085630 192.0.2.9 &gt; 192.0.2.2: ESP(spi=0x5fdd1cf8,seq=0x6)</PRE>
+<P>If you see this, congratulations are in order! You have a tunnel
+ which will protect any IP data from one subnet to the other, as it
+ passes between the two gates. If not, go and<A HREF="trouble.html#trouble">
+ troubleshoot</A>.</P>
+<P>Note: your new tunnel protects only net-net traffic, not
+ gateway-gateway, or gateway-subnet. If you need this (for example, if
+ machines on one net need to securely contact a fileserver on the IPsec
+ gateway), you'll need to create<A HREF="adv_config.html#adv_config">
+ extra connections</A>.</P>
+<H3><A NAME="16_2_6">Finishing touches</A></H3>
+<P>Now that your connection works, name it something sensible, like:</P>
+<PRE>conn winstonnet-toledonet</PRE>
+<P>To have the tunnel come up on-boot, replace</P>
+<PRE>    auto=add</PRE>
+<P>with:</P>
+<PRE>    auto=start</PRE>
+<P>Copy these changes to the other side, for example:</P>
+<PRE>    scp2 ipsec.conf root@ab.example.com:/etc/ipsec.conf</PRE>
+<P>Enjoy!</P>
+<H2><A name="config.rw"></A>Road Warrior Configuration</H2>
+<H3><A name="rw.info.ex">Gather information</A></H3>
+<P>You'll need to know:</P>
+<UL>
+<LI>the gateway's static IP</LI>
+<LI>the IP range of the subnet behind that gateway</LI>
+<LI>a name by which each side can identify itself for IPsec
+ negotiations. Its form is a Fully Qualified Domain Name preceded by an
+ @ sign, ie. @road.example.com.
+<BR> It does not need to be within a domain that you own. It can be a
+ made-up name.</LI>
+</UL>
+<H4>Get your leftrsasigkey...</H4>
+<P>On your laptop, print your IPsec public key:</P>
+<PRE>    ipsec showhostkey --left</PRE>
+<P>The output should look like this (with the key shortened for easy
+ reading):</P>
+<PRE>    # RSA 2192 bits   road.example.com   Sun Jun  9 02:45:02 2002
+    leftrsasigkey=0sAQPIPN9uI...</PRE>
+<P>Don't have a key? See<A HREF="old_config.html#genrsakey"> these
+ instructions</A>.</P>
+<H4>...and your rightrsasigkey</H4>
+<P>Get a console on the gateway:</P>
+<PRE>    ssh2 xy.example.com</PRE>
+<P>View the gateway's public key with:</P>
+<PRE>    ipsec showhostkey --right</PRE>
+<P>This will yield something like</P>
+<PRE>    # RSA 2048 bits   xy.example.com   Fri Apr 26 15:01:41 2002
+    rightrsasigkey=0sAQOnwiBPt...</PRE>
+<H3><A NAME="16_3_2">Customize<VAR> /etc/ipsec.conf</VAR></A></H3>
+<P>On your laptop, copy this template to<VAR> /etc/ipsec.conf</VAR>. (on
+ Mandrake,<VAR> /etc/freeswan/ipsec.conf</VAR>). Substitute the
+ information you've gathered for our example data.</P>
+<PRE>conn road
+    left=%defaultroute             # Picks up our dynamic IP 
+    leftnexthop=%defaultroute      # 
+    leftid=@road.example.com       # Local information
+    leftrsasigkey=0sAQPIPN9uI...   #
+    right=192.0.2.10               # Remote information
+    rightsubnet=10.0.0.0/24        #
+    rightid=@xy.example.com        # 
+    rightrsasigkey=0sAQOnwiBPt...  #
+    auto=add                       # authorizes but doesn't start this
+                                   # connection at startup</PRE>
+<P>The template for the gateway is different. Notice how it reverses<VAR>
+ left</VAR> and<VAR> right</VAR>, in keeping with our convention that<STRONG>
+ L</STRONG>eft is<STRONG> L</STRONG>ocal,<STRONG> R</STRONG>ight<STRONG>
+ R</STRONG>emote. Be sure to switch your rsasigkeys in keeping with
+ this.</P>
+<PRE>    ssh2 xy.example.com
+    vi /etc/ipsec.conf</PRE>
+<P>and add:</P>
+<PRE>conn road
+    left=192.0.2.2                 # Gateway's information
+    leftid=@xy.example.com         #
+    leftsubnet=192.0.2.128/29      #
+    leftrsasigkey=0sAQOnwiBPt...   #
+    rightnexthop=%defaultroute     # correct in many situations
+    right=%any                     # Wildcard: we don't know the laptop's IP
+    rightid=@road.example.com      #
+    rightrsasigkey=0sAQPIPN9uI...  #
+    auto=add                       # authorizes but doesn't start this
+                                   # connection at startup</PRE>
+<H3><A NAME="16_3_3">Start your connection</A></H3>
+<P>You must start the connection from the Road Warrior side. On your
+ laptop, type:</P>
+<PRE>    ipsec auto --start net-to-net</PRE>
+<P>You should see:</P>
+<PRE>104 &quot;net-net&quot; #223: STATE_MAIN_I1: initiate
+106 &quot;road&quot; #301: STATE_MAIN_I2: sent MI2, expecting MR2
+108 &quot;road&quot; #301: STATE_MAIN_I3: sent MI3, expecting MR3
+004 &quot;road&quot; #301: STATE_MAIN_I4: ISAKMP SA established
+112 &quot;road&quot; #302: STATE_QUICK_I1: initiate
+004 &quot;road&quot; #302: STATE_QUICK_I2: sent QI2, IPsec SA established</PRE>
+<P>Look for<VAR> IPsec SA established</VAR>. If you're unsuccessful, see
+ our<A HREF="trouble.html#trouble"> troubleshooting tips</A>.</P>
+<H3><A NAME="16_3_4">Do not MASQ or NAT packets to be tunneled</A></H3>
+<P>If you are using<A HREF="glossary.html#masq"> IP masquerade</A> or<A HREF="glossary.html#NAT.gloss">
+ Network Address Translation (NAT)</A> on either gateway, you must now
+ exempt the packets you wish to tunnel from this treatment. For example,
+ if you have a rule like:</P>
+<PRE>iptables -t nat -A POSTROUTING -o eth0 -s 10.0.0.0/24 -j MASQUERADE
+</PRE>
+<P>change it to something like:</P>
+<PRE>iptables -t nat -A POSTROUTING -o eth0 -s 10.0.0.0/24 -d \! 192.0.2.128/29 -j MASQUERADE</PRE>
+<H3><A NAME="16_3_5">Test your connection</A></H3>
+<P>From your laptop, ping a subnet node behind the remote gateway. Do
+ not choose the gateway itself for this test.</P>
+<PRE>    ping ns.winston.example.com</PRE>
+<P>Snoop the packets exiting the laptop, with a command like:</P>
+<PRE>    tcpdump -i wlan0</PRE>
+<P>You have success if you see (Encapsulating Security Payload) packets
+ travelling<B> in both directions</B>:</P>
+<PRE>    19:16:32.046220 192.0.2.2 &gt; 192.0.2.9: ESP(spi=0x3be6c4dc,seq=0x3)
+    19:16:32.085630 192.0.2.9 &gt; 192.0.2.2: ESP(spi=0x5fdd1cf8,seq=0x6)</PRE>
+<P>If you do, great! Traffic between your Road Warrior and the net
+ behind your gateway is protected. If not, see our<A HREF="trouble.html#trouble">
+ troubleshooting hints</A>.</P>
+<P>Your new tunnel protects only traffic addressed to the net, not to
+ the IPsec gateway itself. If you need the latter, you'll want to make
+ an<A HREF="adv_config.html#adv_config"> extra tunnel.</A>.</P>
+<H3><A NAME="16_3_6">Finishing touches</A></H3>
+<P>On both ends, name your connection wisely, like:</P>
+<PRE>conn mike-to-office</PRE>
+<P><B>On the laptop only,</B> replace</P>
+<PRE>    auto=add</PRE>
+<P>with:</P>
+<PRE>    auto=start</PRE>
+<P>so that you'll be connected on-boot.</P>
+<P>Happy telecommuting!</P>
+<H3><A NAME="16_3_7">Multiple Road Warriors</A></H3>
+<P>If you're using RSA keys, as we did in this example, you can add as
+ many Road Warriors as you like. The left/rightid parameter lets Linux
+ FreeS/WAN distinguish between multiple Road Warrior peers, each with
+ its own public key.</P>
+<P>The situation is different for shared secrets (PSK). During a PSK
+ negotiation, ID information is not available at the time Pluto is
+ trying to determine which secret to use, so, effectively, you can only
+ define one Roadwarrior connection. All your PSK road warriors must
+ therefore share one secret.</P>
+<H2><A NAME="16_4">What next?</A></H2>
+<P>Using the principles illustrated here, you can try variations such
+ as:</P>
+<UL>
+<LI>a telecommuter with a static IP</LI>
+<LI>a road warrior with a subnet behind it</LI>
+</UL>
+<P>Or, look at some of our<A HREF="adv_config.html#adv_config"> more
+ complex configuration examples.</A>.</P>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="install.html">Previous</A>
+<A HREF="background.html">Next</A>
+</BODY>
+</HTML>
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+
+Independent submission                                     M. Richardson
+Internet-Draft                                                       SSW
+Expires: November 19, 2003                                 D. Redelmeier
+                                                                  Mimosa
+                                                            May 21, 2003
+
+
+     Opportunistic Encryption using The Internet Key Exchange (IKE)
+              draft-richardson-ipsec-opportunistic-11.txt
+
+Status of this Memo
+
+   This document is an Internet-Draft and is in full conformance with
+   all provisions of Section 10 of RFC2026.
+
+   Internet-Drafts are working documents of the Internet Engineering
+   Task Force (IETF), its areas, and its working groups.  Note that
+   other groups may also distribute working documents as Internet-
+   Drafts.
+
+   Internet-Drafts are draft documents valid for a maximum of six months
+   and may be updated, replaced, or obsoleted by other documents at any
+   time.  It is inappropriate to use Internet-Drafts as reference
+   material or to cite them other than as "work in progress."
+
+   The list of current Internet-Drafts can be accessed at http://
+   www.ietf.org/ietf/1id-abstracts.txt.
+
+   The list of Internet-Draft Shadow Directories can be accessed at
+   http://www.ietf.org/shadow.html.
+
+   This Internet-Draft will expire on November 19, 2003.
+
+Copyright Notice
+
+   Copyright (C) The Internet Society (2003).  All Rights Reserved.
+
+Abstract
+
+   This document describes opportunistic encryption (OE) using the
+   Internet Key Exchange (IKE) and IPsec.  Each system administrator
+   adds new resource records to his or her Domain Name System (DNS) to
+   support opportunistic encryption.  The objective is to allow
+   encryption for secure communication without any pre-arrangement
+   specific to the pair of systems involved.
+
+   DNS is used to distribute the public keys of each system involved.
+   This is resistant to passive attacks.  The use of DNS Security
+   (DNSSEC) secures this system against active attackers as well.
+
+
+
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+
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+
+
+   As a result, the administrative overhead is reduced from the square
+   of the number of systems to a linear dependence, and it becomes
+   possible to make secure communication the default even when the
+   partner is not known in advance.
+
+   This document is offered up as an Informational RFC.
+
+Table of Contents
+
+   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
+   2.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  6
+   3.  Specification  . . . . . . . . . . . . . . . . . . . . . . . . 10
+   4.  Impacts on IKE . . . . . . . . . . . . . . . . . . . . . . . . 21
+   5.  DNS issues . . . . . . . . . . . . . . . . . . . . . . . . . . 24
+   6.  Network address translation interaction  . . . . . . . . . . . 28
+   7.  Host implementations . . . . . . . . . . . . . . . . . . . . . 29
+   8.  Multi-homing . . . . . . . . . . . . . . . . . . . . . . . . . 30
+   9.  Failure modes  . . . . . . . . . . . . . . . . . . . . . . . . 32
+   10. Unresolved issues  . . . . . . . . . . . . . . . . . . . . . . 34
+   11. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
+   12. Security considerations  . . . . . . . . . . . . . . . . . . . 42
+   13. IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 44
+   14. Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 45
+       Normative references . . . . . . . . . . . . . . . . . . . . . 46
+       Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 47
+       Full Copyright Statement . . . . . . . . . . . . . . . . . . . 48
+
+
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+
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+
+
+1. Introduction
+
+1.1 Motivation
+
+   The objective of opportunistic encryption is to allow encryption
+   without any pre-arrangement specific to the pair of systems involved.
+   Each system administrator adds public key information to DNS records
+   to support opportunistic encryption and then enables this feature in
+   the nodes' IPsec stack.  Once this is done, any two such nodes can
+   communicate securely.
+
+   This document describes opportunistic encryption as designed and
+   mostly implemented by the Linux FreeS/WAN project.  For project
+   information, see http://www.freeswan.org.
+
+   The Internet Architecture Board (IAB) and Internet Engineering
+   Steering Group (IESG) have taken a strong stand that the Internet
+   should use powerful encryption to provide security and privacy [4].
+   The Linux FreeS/WAN project attempts to provide a practical means to
+   implement this policy.
+
+   The project uses the IPsec, ISAKMP/IKE, DNS and DNSSEC protocols
+   because they are standardized, widely available and can often be
+   deployed very easily without changing hardware or software or
+   retraining users.
+
+   The extensions to support opportunistic encryption are simple.  No
+   changes to any on-the-wire formats are needed.  The only changes are
+   to the policy decision making system.  This means that opportunistic
+   encryption can be implemented with very minimal changes to an
+   existing IPsec implementation.
+
+   Opportunistic encryption creates a "fax effect".  The proliferation
+   of the fax machine was possible because it did not require that
+   everyone buy one overnight.  Instead, as each person installed one,
+   the value of having one increased - as there were more people that
+   could receive faxes.  Once opportunistic encryption is installed it
+   automatically recognizes other boxes using opportunistic encryption,
+   without any further configuration by the network administrator.  So,
+   as opportunistic encryption software is installed on more boxes, its
+   value as a tool increases.
+
+   This document describes the infrastructure to permit deployment of
+   Opportunistic Encryption.
+
+   The term S/WAN is a trademark of RSA Data Systems, and is used with
+   permission by this project.
+
+
+
+
+Richardson & Redelmeier    Expires November 19, 2003            [Page 3]
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+
+
+1.2 Types of network traffic
+
+   To aid in understanding the relationship between security processing
+   and IPsec we divide network traffic into four categories:
+
+   * Deny: networks to which traffic is always forbidden.
+
+   * Permit: networks to which traffic in the clear is permitted.
+
+   * Opportunistic tunnel: networks to which traffic is encrypted if
+      possible, but otherwise is in the clear or fails depending on the
+      default policy in place.
+
+   * Configured tunnel: networks to which traffic must be encrypted, and
+      traffic in the clear is never permitted.
+
+   Traditional firewall devices handle the first two categories.  No
+   authentication is required.  The permit policy is currently the
+   default on the Internet.
+
+   This document describes the third category - opportunistic tunnel,
+   which is proposed as the new default for the Internet.
+
+   Category four, encrypt traffic or drop it, requires authentication of
+   the end points.  As the number of end points is typically bounded and
+   is typically under a single authority, arranging for distribution of
+   authentication material, while difficult, does not require any new
+   technology.  The mechanism described here provides an additional way
+   to distribute the authentication materials, that of a public key
+   method that does not require deployment of an X.509 based
+   infrastructure.
+
+   Current Virtual Private Networks can often be replaced by an "OE
+   paranoid" policy as described herein.
+
+1.3 Peer authentication in opportunistic encryption
+
+   Opportunistic encryption creates tunnels between nodes that are
+   essentially strangers.  This is done without any prior bilateral
+   arrangement.  There is, therefore, the difficult question of how one
+   knows to whom one is talking.
+
+   One possible answer is that since no useful authentication can be
+   done, none should be tried.  This mode of operation is named
+   "anonymous encryption".  An active man-in-the-middle attack can be
+   used to thwart the privacy of this type of communication.  Without
+   peer authentication, there is no way to prevent this kind of attack.
+
+
+
+
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+
+
+   Although a useful mode, anonymous encryption is not the goal of this
+   project.  Simpler methods are available that can achieve anonymous
+   encryption only, but authentication of the peer is a desireable goal.
+   The latter is achieved through key distribution in DNS, leveraging
+   upon the authentication of the DNS in DNSSEC.
+
+   Peers are, therefore, authenticated with DNSSEC when available.
+   Local policy determines how much trust to extend when DNSSEC is not
+   available.
+
+   However, an essential premise of building private connections with
+   strangers is that datagrams received through opportunistic tunnels
+   are no more special than datagrams that arrive in the clear.  Unlike
+   in a VPN, these datagrams should not be given any special exceptions
+   when it comes to auditing, further authentication or firewalling.
+
+   When initiating outbound opportunistic encryption, local
+   configuration determines what happens if tunnel setup fails.  It may
+   be that the packet goes out in the clear, or it may be dropped.
+
+1.4 Use of RFC2119 terms
+
+   The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
+   SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this
+   document, are to be interpreted as described in [5]
+
+
+
+
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+Richardson & Redelmeier    Expires November 19, 2003            [Page 5]
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+
+
+2. Overview
+
+2.1 Reference diagram
+
+   ---------------------------------------------------------------------
+
+   The following network diagram is used in the rest of this document as
+   the canonical diagram:
+
+                             [Q]  [R]
+                              .    .              AS2
+     [A]----+----[SG-A].......+....+.......[SG-B]-------[B]
+            |                 ......
+        AS1 |                 ..PI..
+            |                 ......
+     [D]----+----[SG-D].......+....+.......[C] AS3
+
+
+
+                  Figure 1: Reference Network Diagram
+
+   ---------------------------------------------------------------------
+
+   In this diagram, there are four end-nodes: A, B, C and D.  There are
+   three gateways, SG-A, SG-B, SG-D.  A, D, SG-A and SG-D are part of
+   the same administrative authority, AS1.  SG-A and SG-D are on two
+   different exit paths from organization 1.  SG-B/B is an independent
+   organization, AS2.  Nodes Q and R are nodes on the Internet.  PI is
+   the Public Internet ("The Wild").
+
+2.2 Terminology
+
+   The following terminology is used in this document:
+
+   Security gateway: a system that performs IPsec tunnel mode
+      encapsulation/decapsulation.  [SG-x] in the diagram.
+
+   Alice: node [A] in the diagram.  When an IP address is needed, this
+      is 192.1.0.65.
+
+   Bob: node [B] in the diagram.  When an IP address is needed, this is
+      192.2.0.66.
+
+   Carol: node [C] in the diagram.  When an IP address is needed, this
+      is 192.1.1.67.
+
+   Dave: node [D] in the diagram.  When an IP address is needed, this is
+      192.3.0.68.
+
+
+
+Richardson & Redelmeier    Expires November 19, 2003            [Page 6]
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+
+
+   SG-A: Alice's security gateway.  Internally it is 192.1.0.1,
+      externally it is 192.1.1.4.
+
+   SG-B: Bob's security gateway.  Internally it is 192.2.0.1, externally
+      it is 192.1.1.5.
+
+   SG-D: Dave's security gateway.  Also Alice's backup security gateway.
+      Internally it is 192.3.0.1, externally it is 192.1.1.6.
+
+   -  A single dash represents clear-text datagrams.
+
+   =  An equals sign represents phase 2 (IPsec) cipher-text datagrams.
+
+   ~  A single tilde represents clear-text phase 1 datagrams.
+
+   #  A hash sign represents phase 1 (IKE) cipher-text datagrams.
+
+   .  A period represents an untrusted network of unknown type.
+
+   Configured tunnel: a tunnel that is directly and deliberately hand
+      configured on participating gateways.  Configured tunnels are
+      typically given a higher level of trust than opportunistic
+      tunnels.
+
+   Road warrior tunnel: a configured tunnel connecting one node with a
+      fixed IP address and one node with a variable IP address.  A road
+      warrior (RW) connection must be initiated by the variable node,
+      since the fixed node cannot know the current address for the road
+      warrior.
+
+   Anonymous encryption: the process of encrypting a session without any
+      knowledge of who the other parties are.  No authentication of
+      identities is done.
+
+   Opportunistic encryption: the process of encrypting a session with
+      authenticated knowledge of who the other parties are.
+
+   Lifetime: the period in seconds (bytes or datagrams) for which a
+      security association will remain alive before needing to be re-
+      keyed.
+
+   Lifespan: the effective time for which a security association remains
+      useful.  A security association with a lifespan shorter than its
+      lifetime would be removed when no longer needed.  A security
+      association with a lifespan longer than its lifetime would need to
+      be re-keyed one or more times.
+
+   Phase 1 SA: an ISAKMP/IKE security association sometimes referred to
+
+
+
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+
+
+      as a keying channel.
+
+   Phase 2 SA: an IPsec security association.
+
+   Tunnel: another term for a set of phase 2 SA (one in each direction).
+
+   NAT: Network Address Translation (see [20]).
+
+   NAPT: Network Address and Port Translation (see [20]).
+
+   AS: an autonomous system (AS) is a group of systems (a network) that
+      are under the administrative control of a single organization.
+
+   Default-free zone: a set of routers that maintain a complete set of
+      routes to all currently reachable destinations.  Having such a
+      list, these routers never make use of a default route.  A datagram
+      with a destination address not matching any route will be dropped
+      by such a router.
+
+
+2.3 Model of operation
+
+   The opportunistic encryption security gateway (OE gateway) is a
+   regular gateway node as described in [2] section 2.4 and [3] with the
+   additional capabilities described here and in [7].  The algorithm
+   described here provides a way to determine, for each datagram,
+   whether or not to encrypt and tunnel the datagram.  Two important
+   things that must be determined are whether or not to encrypt and
+   tunnel and, if so, the destination address or name of the tunnel end
+   point which should be used.
+
+2.3.1 Tunnel authorization
+
+   The OE gateway determines whether or not to create a tunnel based on
+   the destination address of each packet.  Upon receiving a packet with
+   a destination address not recently seen, the OE gateway performs a
+   lookup in DNS for an authorization resource record (see Section 5.2).
+   The record is located using the IP address to perform a search in the
+   in-addr.arpa (IPv4) or ip6.arpa (IPv6) maps.  If an authorization
+   record is found, the OE gateway interprets this as a request for a
+   tunnel to be formed.
+
+2.3.2 Tunnel end-point discovery
+
+   The authorization resource record also provides the address or name
+   of the tunnel end point which should be used.
+
+   The record may also provide the public RSA key of the tunnel end
+
+
+
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+
+
+   point itself.  This is provided for efficiency only.  If the public
+   RSA key is not present, the OE gateway performs a second lookup to
+   find a KEY resource record for the end point address or name.
+
+   Origin and integrity protection of the resource records is provided
+   by DNSSEC ([16]).  Section 3.2.4.1 documents an optional restriction
+   on the tunnel end point if DNSSEC signatures are not available for
+   the relevant records.
+
+2.3.3 Caching of authorization results
+
+   The OE gateway maintains a cache, in the forwarding plane, of source/
+   destination pairs for which opportunistic encryption has been
+   attempted.  This cache maintains a record of whether or not OE was
+   successful so that subsequent datagrams can be forwarded properly
+   without additional delay.
+
+   Successful negotiation of OE instantiates a new security association.
+   Failure to negotiate OE results in creation of a forwarding policy
+   entry either to drop or transmit in the clear future datagrams.  This
+   negative cache is necessary to avoid the possibly lengthy process of
+   repeatedly looking up the same information.
+
+   The cache is timed out periodically, as described in Section 3.4.
+   This removes entries that are no longer being used and permits the
+   discovery of changes in authorization policy.
+
+
+
+
+
+
+
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+
+
+3. Specification
+
+   The OE gateway is modeled to have a forwarding plane and a control
+   plane.  A control channel, such as PF_KEY, connects the two planes.
+   (See [6].) The forwarding plane performs per datagram operations.
+   The control plane contains a keying daemon, such as ISAKMP/IKE, and
+   performs all authorization, peer authentication and key derivation
+   functions.
+
+3.1 Datagram state machine
+
+   Let the OE gateway maintain a collection of objects -- a superset of
+   the security policy database (SPD) specified in [7].  For each
+   combination of source and destination address, an SPD object exists
+   in one of five following states.  Prior to forwarding each datagram,
+   the responder uses the source and destination addresses to pick an
+   entry from the SPD.  The SPD then determines if and how the packet is
+   forwarded.
+
+3.1.1 Non-existent policy
+
+   If the responder does not find an entry, then this policy applies.
+   The responder creates an entry with an initial state of "hold policy"
+   and requests keying material from the keying daemon.  The responder
+   does not forward the datagram, rather it attaches the datagram to the
+   SPD entry as the  "first" datagram and retains it for eventual
+   transmission in a new state.
+
+3.1.2 Hold policy
+
+   The responder requests keying material.  If the interface to the
+   keying system is lossy (PF_KEY, for instance, can be), the
+   implementation SHOULD include a mechanism to retransmit the keying
+   request at a rate limited to less than 1 request per second.  The
+   responder does not forward the datagram.  It attaches the datagram to
+   the SPD entry as the "last" datagram where it is retained for
+   eventual transmission.  If there is a datagram already so stored,
+   then that already stored datagram is discarded.
+
+   Because the "first" datagram is probably a TCP SYN packet, the
+   responder retains the "first" datagram in an attempt to avoid waiting
+   for a TCP retransmit.  The responder retains the "last" datagram in
+   deference to streaming protocols that find it useful to know how much
+   data has been lost.  These are recommendations to decrease latency.
+   There are no operational requirements for this.
+
+
+
+
+
+
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+
+
+3.1.3 Pass-through policy
+
+   The responder forwards the datagram using the normal forwarding
+   table.  The responder enters this state only by command from the
+   keying daemon, and upon entering this state, also forwards the
+   "first" and "last" datagrams.
+
+3.1.4 Deny policy
+
+   The responder discards the datagram.  The responder enters this state
+   only by command from the keying daemon, and upon entering this state,
+   discards the "first" and "last" datagrams.  Local administration
+   decides if further datagrams cause ICMP messages to be generated
+   (i.e.  ICMP Destination Unreachable, Communication Administratively
+   Prohibited.  type=3, code=13).
+
+3.1.5 Encrypt policy
+
+   The responder encrypts the datagram using the indicated security
+   association database (SAD) entry.  The responder enters this state
+   only by command from the keying daemon, and upon entering this state,
+   releases and forwards the "first" and "last" datagrams using the new
+   encrypt policy.
+
+   If the associated SAD entry expires because of byte, packet or time
+   limits, then the entry returns to the Hold policy, and an expire
+   message is sent to the keying daemon.
+
+   All states may be created directly by the keying daemon while acting
+   as a responder.
+
+3.2 Keying state machine - initiator
+
+   Let the keying daemon maintain a collection of objects.  Let them be
+   called "connections" or "conn"s.  There are two categories of
+   connection objects: classes and instances.  A class represents an
+   abstract policy - what could be.  An instance represents an actual
+   connection - what is implemented at the time.
+
+   Let there be two further subtypes of connections: keying channels
+   (Phase 1 SAs) and data channels (Phase 2 SAs).  Each data channel
+   object may have a corresponding SPD and SAD entry maintained by the
+   datagram state machine.
+
+   For the purposes of opportunistic encryption, there MUST, at least,
+   be connection classes known as "deny", "always-clear-text", "OE-
+   permissive", and "OE-paranoid".  The latter two connection classes
+   define a set of source and/or destination addresses for which
+
+
+
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+
+
+   opportunistic encryption will be attempted.  The administrator MAY
+   set policy options in a number of additional places.  An
+   implementation MAY create additional connection classes to further
+   refine these policies.
+
+   The simplest system may need only the "OE-permissive" connection, and
+   would list its own (single) IP address as the source address of this
+   policy and the wild-card address 0.0.0.0/0 as the destination IPv4
+   address.  That is, the simplest policy is to try opportunistic
+   encryption with all destinations.
+
+   The distinction between permissive and paranoid OE use will become
+   clear in the state transition differences.  In general a permissive
+   OE will, on failure, install a pass-through policy, while a paranoid
+   OE will, on failure, install a drop policy.
+
+   In this description of the keying machine's state transitions, the
+   states associated with the keying system itself are omitted because
+   they are best documented in the keying system ([8], [9] and [10] for
+   ISAKMP/IKE), and the details are keying system specific.
+   Opportunistic encryption is not dependent upon any specific keying
+   protocol, but this document does provide requirements for those using
+   ISAKMP/IKE to assure that implementations inter-operate.
+
+   The state transitions that may be involved in communicating with the
+   forwarding plane are omitted.  PF_KEY and similar protocols have
+   their own set of states required for message sends and completion
+   notifications.
+
+   Finally, the retransmits and recursive lookups that are normal for
+   DNS are not included in this description of the state machine.
+
+3.2.1 Nonexistent connection
+
+   There is no connection instance for a given source/destination
+   address pair.  Upon receipt of a request for keying material for this
+   source/destination pair, the initiator searches through the
+   connection classes to determine the most appropriate policy.  Upon
+   determining an appropriate connection class, an instance object is
+   created of that type.  Both of the OE types result in a potential OE
+   connection.
+
+   Failure to find an appropriate connection class results in an
+   administrator defined default.
+
+   In each case, when the initiator finds an appropriate class for the
+   new flow, an instance connection is made of the class which matched.
+
+
+
+
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+
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+
+
+3.2.2 Clear-text connection
+
+   The non-existent connection makes a transition to this state when an
+   always-clear-text class is instantiated, or when an OE-permissive
+   connection fails.  During the transition, the initiator creates a
+   pass-through policy object in the forwarding plane for the
+   appropriate flow.
+
+   Timing out is the only way to leave this state (see Section 3.2.7).
+
+3.2.3 Deny connection
+
+   The empty connection makes a transition to this state when a deny
+   class is instantiated, or when an OE-paranoid connection fails.
+   During the transition, the initiator creates a deny policy object in
+   the forwarding plane for the appropriate flow.
+
+   Timing out is the only way to leave this state (see Section 3.2.7).
+
+3.2.4 Potential OE connection
+
+   The empty connection makes a transition to this state when one of
+   either OE class is instantiated.  During the transition to this
+   state, the initiator creates a hold policy object in the forwarding
+   plane for the appropriate flow.
+
+   In addition, when making a transition into this state, DNS lookup is
+   done in the reverse-map for a TXT delegation resource record (see
+   Section 5.2).  The lookup key is the destination address of the flow.
+
+   There are three ways to exit this state:
+
+   1.  DNS lookup finds a TXT delegation resource record.
+
+   2.  DNS lookup does not find a TXT delegation resource record.
+
+   3.  DNS lookup times out.
+
+   Based upon the results of the DNS lookup, the potential OE connection
+   makes a transition to the pending OE connection state.  The
+   conditions for a successful DNS look are:
+
+   1.  DNS finds an appropriate resource record
+
+   2.  It is properly formatted according to Section 5.2
+
+   3.  if DNSSEC is enabled, then the signature has been vouched for.
+
+
+
+
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+
+
+   Note that if the initiator does not find the public key present in
+   the TXT delegation record, then the public key must be looked up as a
+   sub-state.  Only successful completion of all the DNS lookups is
+   considered a success.
+
+   If DNS lookup does not find a resource record or DNS times out, then
+   the initiator considers the receiver not OE capable.  If this is an
+   OE-paranoid instance, then the potential OE connection makes a
+   transition to the deny connection state.  If this is an OE-permissive
+   instance, then the potential OE connection makes a transition to the
+   clear-text connection state.
+
+   If the initiator finds a resource record but it is not properly
+   formatted, or if DNSSEC is enabled and reports a failure to
+   authenticate, then the potential OE connection should make a
+   transition to the deny connection state.  This action SHOULD be
+   logged.  If the administrator wishes to override this transition
+   between states, then an always-clear class can be installed for this
+   flow.  An implementation MAY make this situation a new class.
+
+3.2.4.1 Restriction on unauthenticated TXT delegation records
+
+   An implementation SHOULD also provide an additional administrative
+   control on delegation records and DNSSEC.  This control would apply
+   to delegation records (the TXT records in the reverse-map) that are
+   not protected by DNSSEC.  Records of this type are only permitted to
+   delegate to their own address as a gateway.  When this option is
+   enabled, an active attack on DNS will be unable to redirect packets
+   to other than the original destination.
+
+3.2.5 Pending OE connection
+
+   The potential OE connection makes a transition to this state when the
+   initiator determines that all the information required from the DNS
+   lookup is present.  Upon entering this state, the initiator attempts
+   to initiate keying to the gateway provided.
+
+   Exit from this state occurs either with a successfully created IPsec
+   SA, or with a failure of some kind.  Successful SA creation results
+   in a transition to the key connection state.
+
+   Three failures have caused significant problems.  They are clearly
+   not the only possible failures from keying.
+
+   Note that if there are multiple gateways available in the TXT
+   delegation records, then a failure can only be declared after all
+   have been tried.  Further, creation of a phase 1 SA does not
+   constitute success.  A set of phase 2 SAs (a tunnel) is considered
+
+
+
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+
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+
+
+   success.
+
+   The first failure occurs when an ICMP port unreachable is
+   consistently received without any other communication, or when there
+   is silence from the remote end.  This usually means that either the
+   gateway is not alive, or the keying daemon is not functional.  For an
+   OE-permissive connection, the initiator makes a transition to the
+   clear-text connection but with a low lifespan.  For an OE-pessimistic
+   connection, the initiator makes a transition to the deny connection
+   again with a low lifespan.  The lifespan in both cases is kept low
+   because the remote gateway may be in the process of rebooting or be
+   otherwise temporarily unavailable.
+
+   The length of time to wait for the remote keying daemon to wake up is
+   a matter of some debate.  If there is a routing failure, 5 minutes is
+   usually long enough for the network to re-converge.  Many systems can
+   reboot in that amount of time as well.  However, 5 minutes is far too
+   long for most users to wait to hear that they can not connect using
+   OE.  Implementations SHOULD make this a tunable parameter.
+
+   The second failure occurs after a phase 1 SA has been created, but
+   there is either no response to the phase 2 proposal, or the initiator
+   receives a negative notify (the notify must be authenticated).  The
+   remote gateway is not prepared to do OE at this time.  As before, the
+   initiator makes a transition to the clear-text or the deny connection
+   based upon connection class, but this time with a normal lifespan.
+
+   The third failure occurs when there is signature failure while
+   authenticating the remote gateway.  This can occur when there has
+   been a key roll-over, but DNS has not caught up.  In this case again,
+   the initiator makes a transition to the clear-text or the deny
+   connection based upon the connection class.  However, the lifespan
+   depends upon the remaining time to live in the DNS.  (Note that
+   DNSSEC signed resource records have a different expiry time than non-
+   signed records.)
+
+3.2.6 Keyed connection
+
+   The pending OE connection makes a transition to this state when
+   session keying material (the phase 2 SAs) is derived.  The initiator
+   creates an encrypt policy in the forwarding plane for this flow.
+
+   There are three ways to exit this state.  The first is by receipt of
+   an authenticated delete message (via the keying channel) from the
+   peer.  This is normal teardown and results in a transition to the
+   expired connection state.
+
+   The second exit is by expiry of the forwarding plane keying material.
+
+
+
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+
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+
+
+   This starts a re-key operation with a transition back to pending OE
+   connection.  In general, the soft expiry occurs with sufficient time
+   left to continue to use the keys.  A re-key can fail, which may
+   result in the connection failing to clear-text or deny as
+   appropriate.  In the event of a failure, the forwarding plane policy
+   does not change until the phase 2 SA (IPsec SA) reaches its hard
+   expiry.
+
+   The third exit is in response to a negotiation from a remote gateway.
+   If the forwarding plane signals the control plane that it has
+   received an unknown SPI from the remote gateway, or an ICMP is
+   received from the remote gateway indicating an unknown SPI, the
+   initiator should consider that the remote gateway has rebooted or
+   restarted.  Since these indications are easily forged, the
+   implementation must exercise care.  The initiator should make a
+   cautious (rate-limited) attempt to re-key the connection.
+
+3.2.7 Expiring connection
+
+   The initiator will periodically place each of the deny, clear-text,
+   and keyed connections into this sub-state.  See Section 3.4 for more
+   details of how often this occurs.  The initiator queries the
+   forwarding plane for last use time of the appropriate policy.  If the
+   last use time is relatively recent, then the connection returns to
+   the previous deny, clear-text or keyed connection state.  If not,
+   then the connection enters the expired connection state.
+
+   The DNS query and answer that lead to the expiring connection state
+   are also examined.  The DNS query may become stale.  (A negative,
+   i.e.  no such record, answer is valid for the period of time given by
+   the MINIMUM field in an attached SOA record.  See [12] section
+   4.3.4.) If the DNS query is stale, then a new query is made.  If the
+   results change, then the connection makes a transition to a new state
+   as described in potential OE connection state.
+
+   Note that when considering how stale a connection is, both outgoing
+   SPD and incoming SAD must be queried as some flows may be
+   unidirectional for some time.
+
+   Also note that the policy at the forwarding plane is not updated
+   unless there is a conclusion that there should be a change.
+
+3.2.8 Expired connection
+
+   Entry to this state occurs when no datagrams have been forwarded
+   recently via the appropriate SPD and SAD objects.  The objects in the
+   forwarding plane are removed (logging any final byte and packet
+   counts if appropriate) and the connection instance in the keying
+
+
+
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+
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+
+
+   plane is deleted.
+
+   The initiator sends an ISAKMP/IKE delete to clean up the phase 2 SAs
+   as described in Section 3.4.
+
+   Whether or not to delete the phase 1 SAs at this time is left as a
+   local implementation issue.  Implementations that do delete the phase
+   1 SAs MUST send authenticated delete messages to indicate that they
+   are doing so.  There is an advantage to keeping the phase 1 SAs until
+   they expire - they may prove useful again in the near future.
+
+3.3 Keying state machine - responder
+
+   The responder has a set of objects identical to those of the
+   initiator.
+
+   The responder receives an invitation to create a keying channel from
+   an initiator.
+
+3.3.1 Unauthenticated OE peer
+
+   Upon entering this state, the responder starts a DNS lookup for a KEY
+   record for the initiator.  The responder looks in the reverse-map for
+   a KEY record for the initiator if the initiator has offered an
+   ID_IPV4_ADDR, and in the forward map if the initiator has offered an
+   ID_FQDN type.  (See [8] section 4.6.2.1.)
+
+   The responder exits this state upon successful receipt of a KEY from
+   DNS, and use of the key to verify the signature of the initiator.
+
+   Successful authentication of the peer results in a transition to the
+   authenticated OE Peer state.
+
+   Note that the unauthenticated OE peer state generally occurs in the
+   middle of the key negotiation protocol.  It is really a form of
+   pseudo-state.
+
+3.3.2 Authenticated OE Peer
+
+   The peer will eventually propose one or more phase 2 SAs.  The
+   responder uses the source and destination address in the proposal to
+   finish instantiating the connection state using the connection class
+   table.  The responder MUST search for an identical connection object
+   at this point.
+
+   If an identical connection is found, then the responder deletes the
+   old instance, and the new object makes a transition to the pending OE
+   connection state.  This means that new ISAKMP connections with a
+
+
+
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+
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+
+
+   given peer will always use the latest instance, which is the correct
+   one if the peer has rebooted in the interim.
+
+   If an identical connection is not found, then the responder makes the
+   transition according to the rules given for the initiator.
+
+   Note that if the initiator is in OE-paranoid mode and the responder
+   is in either always-clear-text or deny, then no communication is
+   possible according to policy.  An implementation is permitted to
+   create new types of policies such as "accept OE but do not initiate
+   it".  This is a local matter.
+
+3.4 Renewal and teardown
+
+3.4.1 Aging
+
+   A potentially unlimited number of tunnels may exist.  In practice,
+   only a few tunnels are used during a period of time.  Unused tunnels
+   MUST, therefore, be torn down.  Detecting when tunnels are no longer
+   in use is the subject of this section.
+
+   There are two methods for removing tunnels: explicit deletion or
+   expiry.
+
+   Explicit deletion requires an IKE delete message.  As the deletes
+   MUST be authenticated, both ends of the tunnel must maintain the key
+   channel (phase 1 ISAKMP SA).  An implementation which refuses to
+   either maintain or recreate the keying channel SA will be unable to
+   use this method.
+
+   The tunnel expiry method, simply allows the IKE daemon to expire
+   normally without attempting to re-key it.
+
+   Regardless of which method is used to remove tunnels, the
+   implementation requires a method to determine if the tunnel is still
+   in use.  The specifics are a local matter, but  the FreeS/WAN project
+   uses the following criteria.  These criteria are currently
+   implemented in the key management daemon, but could also be
+   implemented at the SPD layer using an idle timer.
+
+   Set a short initial (soft) lifespan of 1 minute since many net flows
+   last only a few seconds.
+
+   At the end of the lifespan, check to see if the tunnel was used by
+   traffic in either direction during the last 30 seconds.  If so,
+   assign a longer tentative lifespan of 20 minutes after which, look
+   again.  If the tunnel is not in use, then close the tunnel.
+
+
+
+
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+
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+
+
+   The expiring state in the key management system (see Section 3.2.7)
+   implements these timeouts.  The timer above may be in the forwarding
+   plane, but then it must be re-settable.
+
+   The tentative lifespan is independent of re-keying; it is just the
+   time when the tunnel's future is next considered.  (The term lifespan
+   is used here rather than lifetime for this reason.) Unlike re-keying,
+   this tunnel use check is not costly and should happen reasonably
+   frequently.
+
+   A multi-step back-off algorithm is not considered worth the effort
+   here.
+
+   If the security gateway and the client host are the same and not a
+   Bump-in-the-Stack or Bump-in-the-Wire implementation, tunnel teardown
+   decisions MAY pay attention to TCP connection status as reported by
+   the local TCP layer.  A still-open TCP connection is almost a
+   guarantee that more traffic is expected.  Closing of the only TCP
+   connection through a tunnel is a strong hint that no more traffic is
+   expected.
+
+3.4.2 Teardown and cleanup
+
+   Teardown should always be coordinated between the two ends of the
+   tunnel by interpreting and sending delete notifications.  There is a
+   detailed sub-state in the expired connection state of the key manager
+   that relates to retransmits of the delete notifications, but this is
+   considered to be a keying system detail.
+
+   On receiving a delete for the outbound SAs of a tunnel (or some
+   subset of them), tear down the inbound ones also and notify the
+   remote end with a delete.  If the local system receives a delete for
+   a tunnel which is no longer in existence, then two delete messages
+   have crossed paths.  Ignore the delete.  The operation has already
+   been completed.  Do not generate any messages in this situation.
+
+   Tunnels are to be considered as bidirectional entities, even though
+   the low-level protocols don't treat them this way.
+
+   When the deletion is initiated locally, rather than as a response to
+   a received delete, send a delete for (all) the inbound SAs of a
+   tunnel.  If the local system does not receive a responding delete for
+   the outbound SAs, try re-sending the original delete.  Three tries
+   spaced 10 seconds apart seems a reasonable level of effort.  A
+   failure of the other end to respond after 3 attempts, indicates that
+   the possibility of further communication is unlikely.  Remove the
+   outgoing SAs.  (The remote system may be a mobile node that is no
+   longer present or powered on.)
+
+
+
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+
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+
+
+   After re-keying, transmission should switch to using the new outgoing
+   SAs (ISAKMP or IPsec) immediately, and the old leftover outgoing SAs
+   should be cleared out promptly (delete should be sent for the
+   outgoing SAs) rather than waiting for them to expire.  This reduces
+   clutter and minimizes confusion for the operator doing diagnostics.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
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+
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+
+
+4. Impacts on IKE
+
+4.1 ISAKMP/IKE protocol
+
+   The IKE wire protocol needs no modifications.  The major changes are
+   implementation issues relating to how the proposals are interpreted,
+   and from whom they may come.
+
+   As opportunistic encryption is designed to be useful between peers
+   without prior operator configuration, an IKE daemon must be prepared
+   to negotiate phase 1 SAs with any node.  This may require a large
+   amount of resources to maintain cookie state, as well as large
+   amounts of entropy for nonces, cookies and so on.
+
+   The major changes to support opportunistic encryption are at the IKE
+   daemon level.  These changes relate to handling of key acquisition
+   requests, lookup of public keys and TXT records, and interactions
+   with firewalls and other security facilities that may be co-resident
+   on the same gateway.
+
+4.2 Gateway discovery process
+
+   In a typical configured tunnel, the address of SG-B is provided via
+   configuration.  Furthermore, the mapping of an SPD entry to a gateway
+   is typically a 1:1 mapping.  When the 0.0.0.0/0 SPD entry technique
+   is used, then the mapping to a gateway is determined by the reverse
+   DNS records.
+
+   The need to do a DNS lookup and wait for a reply will typically
+   introduce a new state and a new event source (DNS replies) to IKE.
+   Although a synchronous DNS request can be implemented for proof of
+   concept, experience is that it can cause very high latencies when a
+   queue of queries must all timeout in series.
+
+   Use of an asynchronous DNS lookup will also permit overlap of DNS
+   lookups with some of the protocol steps.
+
+4.3 Self identification
+
+   SG-A will have to establish its identity.  Use an IPv4 ID in phase 1.
+
+   There are many situations where the administrator of SG-A may not be
+   able to control the reverse DNS records for SG-A's public IP address.
+   Typical situations include dialup connections and most residential-
+   type broadband Internet access (ADSL, cable-modem) connections.  In
+   these situations, a fully qualified domain name that is under the
+   control of SG-A's administrator may be used when acting as an
+   initiator only.  The FQDN ID should be used in phase 1.  See Section
+
+
+
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+
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+
+
+   5.3 for more details and restrictions.
+
+4.4 Public key retrieval process
+
+   Upon receipt of a phase 1 SA proposal with either an IPv4 (IPv6) ID
+   or an FQDN ID, an IKE daemon needs to examine local caches and
+   configuration files to determine if this is part of a configured
+   tunnel.  If no configured tunnels are found, then the implementation
+   should attempt to retrieve a KEY record from the reverse DNS in the
+   case of an IPv4/IPv6 ID, or from the forward DNS in the case of FQDN
+   ID.
+
+   It is reasonable that if other non-local sources of policy are used
+   (COPS, LDAP), they be consulted concurrently but some clear ordering
+   of policy be provided.  Note that due to variances in latency,
+   implementations must wait for positive or negative replies from all
+   sources of policy before making any decisions.
+
+4.5 Interactions with DNSSEC
+
+   The implementation described (1.98) neither uses DNSSEC directly to
+   explicitly verify the authenticity of zone information, nor uses the
+   NXT records to provide authentication of the absence of a TXT or KEY
+   record.  Rather, this implementation uses a trusted path to a DNSSEC
+   capable caching resolver.
+
+   To distinguish between an authenticated and an unauthenticated DNS
+   resource record, a stub resolver capable of returning DNSSEC
+   information MUST be used.
+
+4.6 Required proposal types
+
+4.6.1 Phase 1 parameters
+
+   Main mode MUST be used.
+
+   The initiator MUST offer at least one proposal using some combination
+   of: 3DES, HMAC-MD5 or HMAC-SHA1, DH group 2 or 5.  Group 5 SHOULD be
+   proposed first.  [11]
+
+   The initiator MAY offer additional proposals, but the cipher MUST not
+   be weaker than 3DES.  The initiator SHOULD limit the number of
+   proposals such that the IKE datagrams do not need to be fragmented.
+
+   The responder MUST accept one of the proposals.  If any configuration
+   of the responder is required then the responder is not acting in an
+   opportunistic way.
+
+
+
+
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+
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+
+
+   SG-A SHOULD use an ID_IPV4_ADDR (ID_IPV6_ADDR for IPv6) of the
+   external interface of SG-A for phase 1.  (There is an exception, see
+   Section 5.3.) The authentication method MUST be RSA public key
+   signatures.  The RSA key for SG-A SHOULD be placed into a DNS KEY
+   record in the reverse space of SG-A (i.e.  using in-addr.arpa).
+
+4.6.2 Phase 2 parameters
+
+   SG-A MUST propose a tunnel between Alice and Bob, using 3DES-CBC
+   mode, MD5 or SHA1 authentication.  Perfect Forward Secrecy MUST be
+   specified.
+
+   Tunnel mode MUST be used.
+
+   Identities MUST be ID_IPV4_ADDR_SUBNET with the mask being /32.
+
+   Authorization for SG-A to act on Alice's behalf is determined by
+   looking for a TXT record in the reverse-map at Alice's address.
+
+   Compression SHOULD NOT be mandatory.  It may be offered as an option.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
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+
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+
+
+5. DNS issues
+
+5.1 Use of KEY record
+
+   In order to establish their own identities, SG-A and SG-B SHOULD
+   publish their public keys in their reverse DNS via DNSSEC's KEY
+   record.  See section 3 of RFC 2535 [16].
+
+   For example:
+
+   KEY 0x4200 4 1 AQNJjkKlIk9...nYyUkKK8
+
+   0x4200: The flag bits, indicating that this key is prohibited for
+      confidentiality use (it authenticates the peer only, a separate
+      Diffie-Hellman exchange is used for confidentiality), and that
+      this key is associated with the non-zone entity whose name is the
+      RR owner name.  No other flags are set.
+
+   4: This indicates that this key is for use by IPsec.
+
+   1: An RSA key is present.
+
+   AQNJjkKlIk9...nYyUkKK8: The public key of the host as described in
+      [17].
+
+   Use of several KEY records allows for key rollover.  The SIG Payload
+   in IKE phase 1 SHOULD be accepted if the public key given by any KEY
+   RR validates it.
+
+5.2 Use of TXT delegation record
+
+   Alice publishes a TXT record to provide authorization for SG-A to act
+   on Alice's behalf.  Bob publishes a TXT record to provide
+   authorization for SG-B to act on Bob's behalf.  These records are
+   located in the reverse DNS (in-addr.arpa) for their respective IP
+   addresses.  The reverse DNS SHOULD be secured by DNSSEC, when it is
+   deployed.  DNSSEC is required to defend against active attacks.
+
+   If Alice's address is P.Q.R.S, then she can authorize another node to
+   act on her behalf by publishing records at:
+
+   S.R.Q.P.in-addr.arpa
+
+   The contents of the resource record are expected to be a string that
+   uses the following syntax, as suggested in [15].  (Note that the
+   reply to query may include other TXT resource records used by other
+   applications.)
+
+
+
+
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+
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+
+
+   ---------------------------------------------------------------------
+
+
+   X-IPsec-Server(P)=A.B.C.D KEY
+
+             Figure 2: Format of reverse delegation record
+
+   ---------------------------------------------------------------------
+
+   P: Specifies a precedence for this record.  This is similar to MX
+      record preferences.  Lower numbers have stronger preference.
+
+   A.B.C.D: Specifies the IP address of the Security Gateway for this
+      client machine.
+
+   KEY: Is the encoded RSA Public key of the Security Gateway.  The key
+      is provided here to avoid a second DNS lookup.  If this field is
+      absent, then a KEY resource record should be looked up in the
+      reverse-map of A.B.C.D.  The key is transmitted in base64 format.
+
+   The pieces of the record are separated by any whitespace (space, tab,
+   newline, carriage return).  An ASCII space SHOULD be used.
+
+   In the case where Alice is located at a public address behind a
+   security gateway that has no fixed address (or no control over its
+   reverse-map), then Alice may delegate to a public key by domain name.
+
+   ---------------------------------------------------------------------
+
+
+   X-IPsec-Server(P)=@FQDN KEY
+
+      Figure 3: Format of reverse delegation record (FQDN version)
+
+   ---------------------------------------------------------------------
+
+   P: Is as above.
+
+   FQDN: Specifies the FQDN that the Security Gateway will identify
+      itself with.
+
+   KEY: Is the encoded RSA Public key of the Security Gateway.
+
+   If there is more than one such TXT record with strongest (lowest
+   numbered) precedence, one Security Gateway is picked arbitrarily from
+   those specified in the strongest-preference records.
+
+
+
+
+
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+
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+
+
+5.2.1 Long TXT records
+
+   When packed into transport format, TXT records which are longer than
+   255 characters are divided into smaller <character-strings>.  (See
+   [13] section 3.3 and 3.3.14.) These MUST be reassembled into a single
+   string for processing.  Whitespace characters in the base64 encoding
+   are to be ignored.
+
+5.2.2 Choice of TXT record
+
+   It has been suggested to use the KEY, OPT, CERT, or KX records
+   instead of a TXT record.  None is satisfactory.
+
+   The KEY RR has a protocol field which could be used to indicate a new
+   protocol, and an algorithm field which could be used to indicate
+   different contents in the key data.  However, the KEY record is
+   clearly not intended for storing what are really authorizations, it
+   is just for identities.  Other uses have been discouraged.
+
+   OPT resource records, as defined in [14] are not intended to be used
+   for storage of information.  They are not to be loaded, cached or
+   forwarded.  They are, therefore, inappropriate for use here.
+
+   CERT records [18] can encode almost any set of information.  A custom
+   type code could be used permitting any suitable encoding to be
+   stored, not just X.509.  According to the RFC, the certificate RRs
+   are to be signed internally which may add undesirable and unnecessary
+   bulk.  Larger DNS records may require TCP instead of UDP transfers.
+
+   At the time of protocol design, the CERT RR was not widely deployed
+   and could not be counted upon.  Use of CERT records will be
+   investigated, and may be proposed in a future revision of this
+   document.
+
+   KX records are ideally suited for use instead of TXT records, but had
+   not been deployed at the time of implementation.
+
+5.3 Use of FQDN IDs
+
+   Unfortunately, not every administrator has control over the contents
+   of the reverse-map.  Where the initiator (SG-A) has no suitable
+   reverse-map, the authorization record present in the reverse-map of
+   Alice may refer to a FQDN instead of an IP address.
+
+   In this case, the client's TXT record gives the fully qualified
+   domain name (FQDN) in place of its security gateway's IP address.
+   The initiator should use the ID_FQDN ID-payload in phase 1.  A
+   forward lookup for a KEY record on the FQDN must yield the
+
+
+
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+
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+
+
+   initiator's public key.
+
+   This method can also be used when the external address of SG-A is
+   dynamic.
+
+   If SG-A is acting on behalf of Alice, then Alice must still delegate
+   authority for SG-A to do so in her reverse-map.  When Alice and SG-A
+   are one and the same (i.e.  Alice is acting as an end-node) then
+   there is no need for this when initiating only.
+
+   However, Alice must still delegate to  herself if she wishes others
+   to initiate OE to her.  See Figure 3.
+
+5.4 Key roll-over
+
+   Good cryptographic hygiene says that one should replace public/
+   private key pairs periodically.  Some administrators may wish to do
+   this as often as daily.  Typical DNS propagation delays are
+   determined by the SOA Resource Record MINIMUM parameter, which
+   controls how long DNS replies may be cached.  For reasonable
+   operation of DNS servers, administrators usually want this value to
+   be at least several hours, sometimes as a long as a day.  This
+   presents a problem - a new key MUST not be used prior to it
+   propagating through DNS.
+
+   This problem is dealt with by having the Security Gateway generate a
+   new public/private key pair at least MINIMUM seconds in advance of
+   using it.  It then adds this key to the DNS (both as a second KEY
+   record and in additional TXT delegation records) at key generation
+   time.  Note: only one key is allowed in each TXT record.
+
+   When authenticating, all gateways MUST have available all public keys
+   that are found in DNS for this entity.  This permits the
+   authenticating end to check both the key for "today" and the key for
+   "tomorrow".  Note that it is the end which is creating the signature
+   (possesses the private key) that determines which key is to be used.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
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+
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+
+
+6. Network address translation interaction
+
+   There are no fundamentally new issues for implementing opportunistic
+   encryption in the presence of network address translation.  Rather
+   there are only the regular IPsec issues with NAT traversal.
+
+   There are several situations to consider for NAT.
+
+6.1 Co-located NAT/NAPT
+
+   If SG-A is also performing network address translation on behalf of
+   Alice, then the packet should be translated prior to being subjected
+   to opportunistic encryption.  This is in contrast to typically
+   configured tunnels which often exist to bridge islands of private
+   network address space.  SG-A will use the translated source address
+   for phase 2, and so SG-B will look up that address to confirm SG-A's
+   authorization.
+
+   In the case of NAT (1:1), the address space into which the
+   translation is done MUST be globally unique, and control over the
+   reverse-map is assumed.  Placing of TXT records is possible.
+
+   In the case of NAPT (m:1), the address will be SG-A.  The ability to
+   get KEY and TXT records in place will again depend upon whether or
+   not there is administrative control over the reverse-map.  This is
+   identical to situations involving a single host acting on behalf of
+   itself.  FQDN style can be used to get around a lack of a reverse-map
+   for initiators only.
+
+6.2 SG-A behind NAT/NAPT
+
+   If there is a NAT or NAPT between SG-A and SG-B, then normal IPsec
+   NAT traversal rules apply.  In addition to the transport problem
+   which may be solved by other mechanisms, there is the issue of what
+   phase 1 and phase 2 IDs to use.  While FQDN could be used during
+   phase 1 for SG-A, there is no appropriate ID for phase 2 that permits
+   SG-B to determine that SG-A is in fact authorized to speak for Alice.
+
+6.3 Bob is behind a NAT/NAPT
+
+   If Bob is behind a NAT (perhaps SG-B), then there is, in fact, no way
+   for Alice to address a packet to Bob.  Not only is opportunistic
+   encryption impossible, but it is also impossible for Alice to
+   initiate any communication to Bob.  It may be possible for Bob to
+   initiate in such a situation.  This creates an asymmetry, but this is
+   common for NAPT.
+
+
+
+
+
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+
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+
+
+7. Host implementations
+
+   When Alice and SG-A are components of the same system, they are
+   considered to be a host implementation.  The packet sequence scenario
+   remains unchanged.
+
+   Components marked Alice are the upper layers (TCP, UDP, the
+   application), and SG-A is the IP layer.
+
+   Note that tunnel mode is still required.
+
+   As Alice and SG-A are acting on behalf of themselves, no TXT based
+   delegation record is necessary for Alice to initiate.  She can rely
+   on FQDN in a forward map.  This is particularly attractive to mobile
+   nodes such as notebook computers at conferences.  To respond, Alice/
+   SG-A will still need an entry in Alice's reverse-map.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
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+
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+
+
+8. Multi-homing
+
+   If there are multiple paths between Alice and Bob (as illustrated in
+   the diagram with SG-D), then additional DNS records are required to
+   establish authorization.
+
+   In Figure 1, Alice has two ways to exit her network: SG-A and SG-D.
+   Previously SG-D has been ignored.  Postulate that there are routers
+   between Alice and her set of security gateways (denoted by the +
+   signs and the marking of an autonomous system number for Alice's
+   network).  Datagrams may, therefore, travel to either SG-A or SG-D en
+   route to Bob.
+
+   As long as all network connections are in good order, it does not
+   matter how datagrams exit Alice's network.  When they reach either
+   security gateway, the security gateway will find the TXT delegation
+   record in Bob's reverse-map, and establish an SA with SG-B.
+
+   SG-B has no problem establishing that either of SG-A or SG-D may
+   speak for Alice, because Alice has published two equally weighted TXT
+   delegation records:
+
+   ---------------------------------------------------------------------
+
+
+   X-IPsec-Server(10)=192.1.1.5 AQMM...3s1Q==
+   X-IPsec-Server(10)=192.1.1.6 AAJN...j8r9==
+
+        Figure 4: Multiple gateway delegation example for Alice
+
+   ---------------------------------------------------------------------
+
+   Alice's routers can now do any kind of load sharing needed.  Both SG-
+   A and SG-D send datagrams addressed to Bob through their tunnel to
+   SG-B.
+
+   Alice's use of non-equal weight delegation records to show preference
+   of one gateway over another, has relevance only when SG-B is
+   initiating to Alice.
+
+   If the precedences are the same, then SG-B has a more difficult time.
+   It must decide which of the two tunnels to use.  SG-B has no
+   information about which link is less loaded, nor which security
+   gateway has more cryptographic resources available.  SG-B, in fact,
+   has no knowledge of whether both gateways are even reachable.
+
+   The Public Internet's default-free zone may well know a good route to
+   Alice, but the datagrams that SG-B creates must be addressed to
+
+
+
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+
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+
+
+   either SG-A or SG-D; they can not be addressed to Alice directly.
+
+   SG-B may make a number of choices:
+
+   1.  It can ignore the problem and round robin among the tunnels.
+       This causes losses during times when one or the other security
+       gateway is unreachable.  If this worries Alice, she can change
+       the weights in her TXT delegation records.
+
+   2.  It can send to the gateway from which it most recently received
+       datagrams.  This assumes that routing and reachability are
+       symmetrical.
+
+   3.  It can listen to BGP information from the Internet to decide
+       which system is currently up.  This is clearly much more
+       complicated, but if SG-B is already participating in the BGP
+       peering system to announce Bob, the results data may already be
+       available to it.
+
+   4.  It can refuse to negotiate the second tunnel.  (It is unclear
+       whether or not this is even an option.)
+
+   5.  It can silently replace the outgoing portion of the first tunnel
+       with the second one while still retaining the incoming portions
+       of both.  SG-B can, thus, accept datagrams from either SG-A or
+       SG-D, but send only to the gateway that most recently re-keyed
+       with it.
+
+   Local policy determines which choice SG-B makes.  Note that even if
+   SG-B has perfect knowledge about the reachability of SG-A and SG-D,
+   Alice may not be reachable from either of these security gateways
+   because of internal reachability issues.
+
+   FreeS/WAN implements option 5.  Implementing a different option is
+   being considered.  The multi-homing aspects of OE are not well
+   developed and may be the subject of a future document.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
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+
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+
+
+9. Failure modes
+
+9.1 DNS failures
+
+   If a DNS server fails to respond, local policy decides whether or not
+   to permit communication in the clear as embodied in the connection
+   classes in Section 3.2.  It is easy to mount a denial of service
+   attack on the DNS server responsible for a particular network's
+   reverse-map.  Such an attack may cause all communication with that
+   network to go in the clear if the policy is permissive, or fail
+   completely if the policy is paranoid.  Please note that this is an
+   active attack.
+
+   There are still many networks that do not have properly configured
+   reverse-maps.  Further, if the policy is not to communicate, the
+   above denial of service attack isolates the target network.
+   Therefore, the decision of whether or not to permit communication in
+   the clear MUST be a matter of local policy.
+
+9.2 DNS configured, IKE failures
+
+   DNS records claim that opportunistic encryption should occur, but the
+   target gateway either does not respond on port 500, or refuses the
+   proposal.  This may be because of a crash or reboot, a faulty
+   configuration, or a firewall filtering port 500.
+
+   The receipt of ICMP port, host or network unreachable messages
+   indicates a potential problem, but MUST NOT cause communication to
+   fail immediately.  ICMP messages are easily forged by attackers.  If
+   such a forgery caused immediate failure, then an active attacker
+   could easily prevent any encryption from ever occurring, possibly
+   preventing all communication.
+
+   In these situations a clear log should be produced and local policy
+   should dictate if communication is then permitted in the clear.
+
+9.3 System reboots
+
+   Tunnels sometimes go down because the remote end crashes,
+   disconnects, or has a network link break.  In general there is no
+   notification of this.  Even in the event of a crash and successful
+   reboot, other SGs don't hear about it unless the rebooted SG has
+   specific reason to talk to them immediately.  Over-quick response to
+   temporary network outages is undesirable.  Note that a tunnel can be
+   torn down and then re-established without any effect visible to the
+   user except a pause in traffic.  On the other hand, if one end
+   reboots, the other end can't get datagrams to it at all (except via
+   IKE) until the situation is noticed.  So a bias toward quick response
+
+
+
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+
+
+   is appropriate even at the cost of occasional false alarms.
+
+   A mechanism for recovery after reboot is a topic of current research
+   and is not specified in this document.
+
+   A deliberate shutdown should include an attempt, using deletes, to
+   notify all other SGs currently connected by phase 1 SAs that
+   communication is about to fail.  Again, a remote SG will assume this
+   is a teardown.  Attempts by the remote SGs to negotiate new tunnels
+   as replacements should be ignored.  When possible, SGs should attempt
+   to preserve information about currently-connected SGs in non-volatile
+   storage, so that after a crash, an Initial-Contact can be sent to
+   previous partners to indicate loss of all previously established
+   connections.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
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+
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+
+
+10. Unresolved issues
+
+10.1 Control of reverse DNS
+
+   The method of obtaining information by reverse DNS lookup causes
+   problems for people who cannot control their reverse DNS bindings.
+   This is an unresolved problem in this version, and is out of scope.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
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+
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+
+
+11. Examples
+
+11.1 Clear-text usage (permit policy)
+
+   Two example scenarios follow.  In the first example GW-A (Gateway A)
+   and GW-B (Gateway B) have always-clear-text policies, and in the
+   second example they have an OE policy.
+
+   ---------------------------------------------------------------------
+
+
+     Alice         SG-A       DNS       SG-B           Bob
+      (1)
+       ------(2)-------------->
+       <-----(3)---------------
+      (4)----(5)----->
+                      ----------(6)------>
+                                          ------(7)----->
+                                         <------(8)------
+                      <----------(9)------
+       <----(10)-----
+      (11)----------->
+                      ----------(12)----->
+                                          -------------->
+                                         <---------------
+                      <-------------------
+       <-------------
+
+                Figure 5: Timing of regular transaction
+
+   ---------------------------------------------------------------------
+
+   Alice wants to communicate with Bob.  Perhaps she wants to retrieve a
+   web page from Bob's web server.  In the absence of opportunistic
+   encryptors, the following events occur:
+
+   (1) Human or application 'clicks' with a name.
+
+   (2) Application looks up name in DNS to get IP address.
+
+   (3) Resolver returns A record to application.
+
+   (4) Application starts a TCP session or UDP session and OS sends
+      datagram.
+
+   (5) Datagram is seen at first gateway from Alice (SG-A).  (SG-A makes
+      a transition through Empty connection to always-clear connection
+      and instantiates a pass-through policy at the forwarding plane.)
+
+
+
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+
+
+   (6) Datagram is seen at last gateway before Bob (SG-B).
+
+   (7) First datagram from Alice is seen by Bob.
+
+   (8) First return datagram is sent by Bob.
+
+   (9) Datagram is seen at Bob's gateway.  (SG-B makes a transition
+      through Empty connection to always-clear connection and
+      instantiates a pass-through policy at the forwarding plane.)
+
+   (10) Datagram is seen at Alice's gateway.
+
+   (11) OS hands datagram to application.  Alice sends another datagram.
+
+   (12) A second datagram traverses the Internet.
+
+
+11.2 Opportunistic encryption
+
+   In the presence of properly configured opportunistic encryptors, the
+   event list is extended.
+
+   ---------------------------------------------------------------------
+
+
+     Alice          SG-A      DNS       SG-B           Bob
+      (1)
+       ------(2)-------------->
+       <-----(3)---------------
+      (4)----(5)----->+
+                     ----(5B)->
+                     <---(5C)--
+                     ~~~~~~~~~~~~~(5D)~~~>
+                     <~~~~~~~~~~~~(5E1)~~~
+                     ~~~~~~~~~~~~~(5E2)~~>
+                     <~~~~~~~~~~~~(5E3)~~~
+                     #############(5E4)##>
+                     <############(5E5)###
+                              <----(5F1)--
+                              -----(5F2)->
+                     #############(5G1)##>
+                              <----(5H1)--
+                              -----(5H2)->
+                     <############(5G2)###
+                     #############(5G3)##>
+                      ============(6)====>
+   		                       ------(7)----->
+                                         <------(8)------
+
+
+
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+
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+
+
+                     <==========(9)======
+       <-----(10)----
+      (11)----------->
+                      ==========(12)=====>
+                                          -------------->
+                                         <---------------
+                      <===================
+       <-------------
+
+        Figure 6: Timing of opportunistic encryption transaction
+
+   ---------------------------------------------------------------------
+
+   (1) Human or application clicks with a name.
+
+   (2) Application initiates DNS mapping.
+
+   (3) Resolver returns A record to application.
+
+   (4) Application starts a TCP session or UDP.
+
+   (5) SG-A (host or SG) sees datagram to target, and buffers it.
+
+   (5B) SG-A asks DNS for TXT record.
+
+   (5C) DNS returns TXT record(s).
+
+   (5D) Initial IKE Main Mode Packet goes out.
+
+   (5E) IKE ISAKMP phase 1 succeeds.
+
+   (5F) SG-B asks DNS for TXT record to prove SG-A is an agent for
+      Alice.
+
+   (5G) IKE phase 2 negotiation.
+
+   (5H) DNS lookup by responder (SG-B).
+
+   (6) Buffered datagram is sent by SG-A.
+
+   (7) Datagram is received by SG-B, decrypted, and sent to Bob.
+
+   (8) Bob replies, and datagram is seen by SG-B.
+
+   (9) SG-B already has tunnel up with SG-A, and uses it.
+
+   (10) SG-A decrypts datagram and gives it to Alice.
+
+
+
+
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+
+
+   (11) Alice receives datagram.  Sends new packet to Bob.
+
+   (12) SG-A gets second datagram, sees that tunnel is up, and uses it.
+
+   For the purposes of this section, we will describe only the changes
+   that occur between Figure 5 and Figure 6.  This corresponds to time
+   points 5, 6, 7, 9 and 10 on the list above.
+
+11.2.1 (5) IPsec datagram interception
+
+   At point (5), SG-A intercepts the datagram because this source/
+   destination pair lacks a policy (the non-existent policy state).  SG-
+   A creates a hold policy, and buffers the datagram.  SG-A requests
+   keys from the keying daemon.
+
+11.2.2 (5B) DNS lookup for TXT record
+
+   SG-A's IKE daemon, having looked up the source/destination pair in
+   the connection class list, creates a new Potential OE connection
+   instance.  SG-A starts DNS queries.
+
+11.2.3 (5C) DNS returns TXT record(s)
+
+   DNS returns properly formed TXT delegation records, and SG-A's IKE
+   daemon causes this instance to make a transition from Potential OE
+   connection to Pending OE connection.
+
+   Using the example above, the returned record might contain:
+
+   ---------------------------------------------------------------------
+
+
+   X-IPsec-Server(10)=192.1.1.5 AQMM...3s1Q==
+
+         Figure 7: Example of reverse delegation record for Bob
+
+   ---------------------------------------------------------------------
+
+    with SG-B's IP address and public key listed.
+
+11.2.4 (5D) Initial IKE main mode packet goes out
+
+   Upon entering Pending OE connection, SG-A sends the initial ISAKMP
+   message with proposals.  See Section 4.6.1.
+
+11.2.5 (5E1) Message 2 of phase 1 exchange
+
+   SG-B receives the message.  A new connection instance is created in
+
+
+
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+
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+
+
+   the unauthenticated OE peer state.
+
+11.2.6 (5E2) Message 3 of phase 1 exchange
+
+   SG-A sends a Diffie-Hellman exponent.  This is an internal state of
+   the keying daemon.
+
+11.2.7 (5E3) Message 4 of phase 1 exchange
+
+   SG-B responds with a Diffie-Hellman exponent.  This is an internal
+   state of the keying protocol.
+
+11.2.8 (5E4) Message 5 of phase 1 exchange
+
+   SG-A uses the phase 1 SA to send its identity under encryption.  The
+   choice of identity is discussed in Section 4.6.1.  This is an
+   internal state of the keying protocol.
+
+11.2.9 (5F1) Responder lookup of initiator key
+
+   SG-B asks DNS for the public key of the initiator.  DNS looks for a
+   KEY record by IP address in the reverse-map.  That is, a KEY resource
+   record is queried for 4.1.1.192.in-addr.arpa (recall that SG-A's
+   external address is 192.1.1.4).  SG-B uses the resulting public key
+   to authenticate the initiator.  See Section 5.1 for further details.
+
+11.2.10 (5F2) DNS replies with public key of initiator
+
+   Upon successfully authenticating the peer, the connection instance
+   makes a transition to authenticated OE peer on SG-B.
+
+   The format of the TXT record returned is described in Section 5.2.
+
+11.2.11 (5E5) Responder replies with ID and authentication
+
+   SG-B sends its ID along with authentication material.  This is an
+   internal state for the keying protocol.
+
+11.2.12 (5G) IKE phase 2
+
+11.2.12.1 (5G1) Initiator proposes tunnel
+
+   Having established mutually agreeable authentications (via KEY) and
+   authorizations (via TXT), SG-A proposes to create an IPsec tunnel for
+   datagrams transiting from Alice to Bob.  This tunnel is established
+   only for the Alice/Bob combination, not for any subnets that may be
+   behind SG-A and SG-B.
+
+
+
+
+Richardson & Redelmeier    Expires November 19, 2003           [Page 39]
+
+Internet-Draft                opportunistic                     May 2003
+
+
+11.2.12.2 (5H1) Responder determines initiator's authority
+
+   While the identity of SG-A has been established, its authority to
+   speak for Alice has not yet been confirmed.  SG-B does a reverse
+   lookup on Alice's address for a TXT record.
+
+   Upon receiving this specific proposal, SG-B's connection instance
+   makes a transition into the potential OE connection state.  SG-B may
+   already have an instance, and the check is made as described above.
+
+11.2.12.3 (5H2) DNS replies with TXT record(s)
+
+   The returned key and IP address should match that of SG-A.
+
+11.2.12.4 (5G2) Responder agrees to proposal
+
+   Should additional communication occur between, for instance, Dave and
+   Bob using SG-A and SG-B, a new tunnel (phase 2 SA) would be
+   established.  The phase 1 SA may be reusable.
+
+   SG-A, having successfully keyed the tunnel, now makes a transition
+   from Pending OE connection to Keyed OE connection.
+
+   The responder MUST setup the inbound IPsec SAs before sending its
+   reply.
+
+11.2.12.5 (5G3) Final acknowledgment from initiator
+
+   The initiator agrees with the responder's choice and sets up the
+   tunnel.  The initiator sets up the inbound and outbound IPsec SAs.
+
+   The proper authorization returned with keys prompts SG-B to make a
+   transition to the keyed OE connection state.
+
+   Upon receipt of this message, the responder may now setup the
+   outbound IPsec SAs.
+
+11.2.13 (6) IPsec succeeds, and sets up tunnel for communication between
+        Alice and Bob
+
+   SG-A sends the datagram saved at step (5) through the newly created
+   tunnel to SG-B, where it gets decrypted and forwarded.  Bob receives
+   it at (7) and replies at (8).
+
+11.2.14 (9) SG-B already has tunnel up with G1 and uses it
+
+   At (9), SG-B has already established an SPD entry mapping Bob->Alice
+   via a tunnel, so this tunnel is simply applied.  The datagram is
+
+
+
+Richardson & Redelmeier    Expires November 19, 2003           [Page 40]
+
+Internet-Draft                opportunistic                     May 2003
+
+
+   encrypted to SG-A, decrypted by SG-A and passed to Alice at (10).
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
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+
+Richardson & Redelmeier    Expires November 19, 2003           [Page 41]
+
+Internet-Draft                opportunistic                     May 2003
+
+
+12. Security considerations
+
+12.1 Configured vs opportunistic tunnels
+
+   Configured tunnels are those which are setup using bilateral
+   mechanisms: exchanging public keys (raw RSA, DSA, PKIX), pre-shared
+   secrets, or by referencing keys that are in known places
+   (distinguished name from LDAP, DNS).  These keys are then used to
+   configure a specific tunnel.
+
+   A pre-configured tunnel may be on all the time, or may be keyed only
+   when needed.  The end points of the tunnel are not necessarily
+   static: many mobile applications (road warrior) are considered to be
+   configured tunnels.
+
+   The primary characteristic is that configured tunnels are assigned
+   specific security properties.  They may be trusted in different ways
+   relating to exceptions to firewall rules, exceptions to NAT
+   processing, and to bandwidth or other quality of service
+   restrictions.
+
+   Opportunistic tunnels are not inherently trusted in any strong way.
+   They are created without prior arrangement.  As the two parties are
+   strangers, there MUST be no confusion of datagrams that arrive from
+   opportunistic peers and those that arrive from configured tunnels.  A
+   security gateway MUST take care that an opportunistic peer can not
+   impersonate a configured peer.
+
+   Ingress filtering MUST be used to make sure that only datagrams
+   authorized by negotiation (and the concomitant authentication and
+   authorization) are accepted from a tunnel.  This is to prevent one
+   peer from impersonating another.
+
+   An implementation suggestion is to treat opportunistic tunnel
+   datagrams as if they arrive on a logical interface distinct from
+   other configured tunnels.  As the number of opportunistic tunnels
+   that may be created automatically on a system is potentially very
+   high, careful attention to scaling should be taken into account.
+
+   As with any IKE negotiation, opportunistic encryption cannot be
+   secure without authentication.  Opportunistic encryption relies on
+   DNS for its authentication information and, therefore, cannot be
+   fully secure without a secure DNS.  Without secure DNS, opportunistic
+   encryption can protect against passive eavesdropping but not against
+   active man-in-the-middle attacks.
+
+
+
+
+
+
+Richardson & Redelmeier    Expires November 19, 2003           [Page 42]
+
+Internet-Draft                opportunistic                     May 2003
+
+
+12.2 Firewalls versus Opportunistic Tunnels
+
+   Typical usage of per datagram access control lists is to implement
+   various kinds of security gateways.  These are typically called
+   "firewalls".
+
+   Typical usage of a virtual private network (VPN) within a firewall is
+   to bypass all or part of the access controls between two networks.
+   Additional trust (as outlined in the previous section) is given to
+   datagrams that arrive in the VPN.
+
+   Datagrams that arrive via opportunistically configured tunnels MUST
+   not be trusted.  Any security policy that would apply to a datagram
+   arriving in the clear SHOULD also be applied to datagrams arriving
+   opportunistically.
+
+12.3 Denial of service
+
+   There are several different forms of denial of service that an
+   implementor should concern themselves with.  Most of these problems
+   are shared with security gateways that have large numbers of mobile
+   peers (road warriors).
+
+   The design of ISAKMP/IKE, and its use of cookies, defend against many
+   kinds of denial of service.  Opportunism changes the assumption that
+   if the phase 1 (ISAKMP) SA is authenticated, that it was worthwhile
+   creating.  Because the gateway will communicate with any machine, it
+   is possible to form phase 1 SAs with any machine on the Internet.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
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+
+
+
+
+
+
+
+Richardson & Redelmeier    Expires November 19, 2003           [Page 43]
+
+Internet-Draft                opportunistic                     May 2003
+
+
+13. IANA Considerations
+
+   There are no known numbers which IANA will need to manage.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
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+
+Richardson & Redelmeier    Expires November 19, 2003           [Page 44]
+
+Internet-Draft                opportunistic                     May 2003
+
+
+14. Acknowledgments
+
+   Substantive portions of this document are based upon previous work by
+   Henry Spencer.
+
+   Thanks to Tero Kivinen, Sandy Harris, Wes Hardarker, Robert
+   Moskowitz, Jakob Schlyter, Bill Sommerfeld, John Gilmore and John
+   Denker for their comments and constructive criticism.
+
+   Sandra Hoffman and Bill Dickie did the detailed proof reading and
+   editing.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
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+
+Richardson & Redelmeier    Expires November 19, 2003           [Page 45]
+
+Internet-Draft                opportunistic                     May 2003
+
+
+Normative references
+
+   [1]   Redelmeier, D. and H. Spencer, "Opportunistic Encryption",
+         paper http://www.freeswan.org/freeswan_trees/freeswan-1.91/doc/
+         opportunism.spec, May 2001.
+
+   [2]   Defense Advanced Research Projects Agency (DARPA), Information
+         Processing Techniques Office and University of Southern
+         California (USC)/Information Sciences Institute, "Internet
+         Protocol", STD 5, RFC 791, September 1981.
+
+   [3]   Braden, R. and J. Postel, "Requirements for Internet gateways",
+         RFC 1009, June 1987.
+
+   [4]   IAB, IESG, Carpenter, B. and F. Baker, "IAB and IESG Statement
+         on Cryptographic Technology and the Internet", RFC 1984, August
+         1996.
+
+   [5]   Bradner, S., "Key words for use in RFCs to Indicate Requirement
+         Levels", BCP 14, RFC 2119, March 1997.
+
+   [6]   McDonald, D., Metz, C. and B. Phan, "PF_KEY Key Management API,
+         Version 2", RFC 2367, July 1998.
+
+   [7]   Kent, S. and R. Atkinson, "Security Architecture for the
+         Internet Protocol", RFC 2401, November 1998.
+
+   [8]   Piper, D., "The Internet IP Security Domain of Interpretation
+         for ISAKMP", RFC 2407, November 1998.
+
+   [9]   Maughan, D., Schneider, M. and M. Schertler, "Internet Security
+         Association and Key Management Protocol (ISAKMP)", RFC 2408,
+         November 1998.
+
+   [10]  Harkins, D. and D. Carrel, "The Internet Key Exchange (IKE)",
+         RFC 2409, November 1998.
+
+   [11]  Kivinen, T. and M. Kojo, "More MODP Diffie-Hellman groups for
+         IKE", RFC 3526, March 2003.
+
+   [12]  Mockapetris, P., "Domain names - concepts and facilities", STD
+         13, RFC 1034, November 1987.
+
+   [13]  Mockapetris, P., "Domain names - implementation and
+         specification", STD 13, RFC 1035, November 1987.
+
+   [14]  Vixie, P., "Extension Mechanisms for DNS (EDNS0)", RFC 2671,
+         August 1999.
+
+
+
+Richardson & Redelmeier    Expires November 19, 2003           [Page 46]
+
+Internet-Draft                opportunistic                     May 2003
+
+
+   [15]  Rosenbaum, R., "Using the Domain Name System To Store Arbitrary
+         String Attributes", RFC 1464, May 1993.
+
+   [16]  Eastlake, D., "Domain Name System Security Extensions", RFC
+         2535, March 1999.
+
+   [17]  Eastlake, D., "RSA/SHA-1 SIGs and RSA KEYs in the Domain Name
+         System (DNS)", RFC 3110, May 2001.
+
+   [18]  Eastlake, D. and O. Gudmundsson, "Storing Certificates in the
+         Domain Name System (DNS)", RFC 2538, March 1999.
+
+   [19]  Durham, D., Boyle, J., Cohen, R., Herzog, S., Rajan, R. and A.
+         Sastry, "The COPS (Common Open Policy Service) Protocol", RFC
+         2748, January 2000.
+
+   [20]  Srisuresh, P. and M. Holdrege, "IP Network Address Translator
+         (NAT) Terminology and Considerations", RFC 2663, August 1999.
+
+
+Authors' Addresses
+
+   Michael C. Richardson
+   Sandelman Software Works
+   470 Dawson Avenue
+   Ottawa, ON  K1Z 5V7
+   CA
+
+   EMail: mcr@sandelman.ottawa.on.ca
+   URI:   http://www.sandelman.ottawa.on.ca/
+
+
+   D. Hugh Redelmeier
+   Mimosa
+   Toronto, ON
+   CA
+
+   EMail: hugh@mimosa.com
+
+
+
+
+
+
+
+
+
+
+
+
+
+Richardson & Redelmeier    Expires November 19, 2003           [Page 47]
+
+Internet-Draft                opportunistic                     May 2003
+
+
+Full Copyright Statement
+
+   Copyright (C) The Internet Society (2003).  All Rights Reserved.
+
+   This document and translations of it may be copied and furnished to
+   others, and derivative works that comment on or otherwise explain it
+   or assist in its implementation may be prepared, copied, published
+   and distributed, in whole or in part, without restriction of any
+   kind, provided that the above copyright notice and this paragraph are
+   included on all such copies and derivative works.  However, this
+   document itself may not be modified in any way, such as by removing
+   the copyright notice or references to the Internet Society or other
+   Internet organizations, except as needed for the purpose of
+   developing Internet standards in which case the procedures for
+   copyrights defined in the Internet Standards process must be
+   followed, or as required to translate it into languages other than
+   English.
+
+   The limited permissions granted above are perpetual and will not be
+   revoked by the Internet Society or its successors or assigns.
+
+   This document and the information contained herein is provided on an
+   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
+   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
+   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
+   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
+   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
+
+Acknowledgement
+
+   Funding for the RFC Editor function is currently provided by the
+   Internet Society.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Richardson & Redelmeier    Expires November 19, 2003           [Page 48]
+
diff --git a/doc/draft-richardson-ipsec-rr.txt b/doc/draft-richardson-ipsec-rr.txt
new file mode 100644
index 000000000..7c229b8e1
--- /dev/null
+++ b/doc/draft-richardson-ipsec-rr.txt
@@ -0,0 +1,840 @@
+
+
+IPSECKEY WG                                                M. Richardson
+Internet-Draft                                                       SSW
+Expires: March 4, 2004                                 September 4, 2003
+
+
+           A method for storing IPsec keying material in DNS.
+                     draft-ietf-ipseckey-rr-07.txt
+
+Status of this Memo
+
+   This document is an Internet-Draft and is in full conformance with
+   all provisions of Section 10 of RFC2026.
+
+   Internet-Drafts are working documents of the Internet Engineering
+   Task Force (IETF), its areas, and its working groups.  Note that
+   other groups may also distribute working documents as Internet-
+   Drafts.
+
+   Internet-Drafts are draft documents valid for a maximum of six months
+   and may be updated, replaced, or obsoleted by other documents at any
+   time.  It is inappropriate to use Internet-Drafts as reference
+   material or to cite them other than as "work in progress."
+
+   The list of current Internet-Drafts can be accessed at http://
+   www.ietf.org/ietf/1id-abstracts.txt.
+
+   The list of Internet-Draft Shadow Directories can be accessed at
+   http://www.ietf.org/shadow.html.
+
+   This Internet-Draft will expire on March 4, 2004.
+
+Copyright Notice
+
+   Copyright (C) The Internet Society (2003).  All Rights Reserved.
+
+Abstract
+
+   This document describes a new resource record for DNS.  This record
+   may be used to store public keys for use in IPsec systems.
+
+   This record replaces the functionality of the sub-type #1 of the KEY
+   Resource Record, which has been obsoleted by RFC3445.
+
+
+
+
+
+
+
+
+
+
+Richardson                Expires March 4, 2004                 [Page 1]
+
+Internet-Draft                   ipsecrr                  September 2003
+
+
+Table of Contents
+
+   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
+   1.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  3
+   1.2 Usage Criteria . . . . . . . . . . . . . . . . . . . . . . . .  3
+   2.  Storage formats  . . . . . . . . . . . . . . . . . . . . . . .  4
+   2.1 IPSECKEY RDATA format  . . . . . . . . . . . . . . . . . . . .  4
+   2.2 RDATA format - precedence  . . . . . . . . . . . . . . . . . .  4
+   2.3 RDATA format - algorithm type  . . . . . . . . . . . . . . . .  4
+   2.4 RDATA format - gateway type  . . . . . . . . . . . . . . . . .  4
+   2.5 RDATA format - gateway . . . . . . . . . . . . . . . . . . . .  5
+   2.6 RDATA format - public keys . . . . . . . . . . . . . . . . . .  5
+   3.  Presentation formats . . . . . . . . . . . . . . . . . . . . .  7
+   3.1 Representation of IPSECKEY RRs . . . . . . . . . . . . . . . .  7
+   3.2 Examples . . . . . . . . . . . . . . . . . . . . . . . . . . .  7
+   4.  Security Considerations  . . . . . . . . . . . . . . . . . . .  9
+   4.1 Active attacks against unsecured IPSECKEY resource records . .  9
+   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 11
+   6.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 12
+       Normative references . . . . . . . . . . . . . . . . . . . . . 13
+       Non-normative references . . . . . . . . . . . . . . . . . . . 14
+       Author's Address . . . . . . . . . . . . . . . . . . . . . . . 14
+       Full Copyright Statement . . . . . . . . . . . . . . . . . . . 15
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Richardson                Expires March 4, 2004                 [Page 2]
+
+Internet-Draft                   ipsecrr                  September 2003
+
+
+1. Introduction
+
+   The type number for the IPSECKEY RR is TBD.
+
+1.1 Overview
+
+   The IPSECKEY resource record (RR) is used to publish a public key
+   that is to be associated with a Domain Name System (DNS) name for use
+   with the IPsec protocol suite.  This can be the  public key of a
+   host, network, or application (in the case of per-port keying).
+
+   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
+   "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in this
+   document are to be interpreted as described in RFC2119 [8].
+
+1.2 Usage Criteria
+
+   An IPSECKEY resource record SHOULD be used in combination with DNSSEC
+   unless some other means of authenticating the IPSECKEY resource
+   record is available.
+
+   It is expected that there will often be multiple IPSECKEY resource
+   records at the same name.  This will be due to the presence of
+   multiple gateways and the need to rollover keys.
+
+   This resource record is class independent.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Richardson                Expires March 4, 2004                 [Page 3]
+
+Internet-Draft                   ipsecrr                  September 2003
+
+
+2. Storage formats
+
+2.1 IPSECKEY RDATA format
+
+   The RDATA for an IPSECKEY RR consists of a precedence value, a public
+   key, algorithm type, and an optional gateway address.
+
+       0                   1                   2                   3
+       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+      |  precedence   | gateway type  |  algorithm  |     gateway     |
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-------------+                 +
+      ~                            gateway                            ~
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+      |                                                               /
+      /                          public key                           /
+      /                                                               /
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|
+
+
+2.2 RDATA format - precedence
+
+   This is an 8-bit precedence for this record.  This is interpreted in
+   the same way as the PREFERENCE field described in section 3.3.9 of
+   RFC1035 [2].
+
+   Gateways listed in IPSECKEY records with  lower precedence are to be
+   attempted first.  Where there is a tie in precedence, the order
+   should be non-deterministic.
+
+2.3 RDATA format - algorithm type
+
+   The algorithm type field identifies the public key's cryptographic
+   algorithm and determines the format of the public key field.
+
+   A value of 0 indicates that no key is present.
+
+   The following values are defined:
+
+   1  A DSA key is present, in the format defined in RFC2536 [11]
+
+   2  A RSA key is present, in the format defined in RFC3110 [12]
+
+
+2.4 RDATA format - gateway type
+
+   The gateway type field indicates the format of the information that
+   is stored in the gateway field.
+
+
+
+Richardson                Expires March 4, 2004                 [Page 4]
+
+Internet-Draft                   ipsecrr                  September 2003
+
+
+   The following values are defined:
+
+   0  No gateway is present
+
+   1  A 4-byte IPv4 address is present
+
+   2  A 16-byte IPv6 address is present
+
+   3  A wire-encoded domain name is present.  The wire-encoded format is
+      self-describing, so the length is implicit.  The domain name MUST
+      NOT be compressed.
+
+
+2.5 RDATA format - gateway
+
+   The gateway field indicates a gateway to which an IPsec tunnel may be
+   created in order to reach the entity named by this resource record.
+
+   There are three formats:
+
+   A 32-bit IPv4 address is present in the gateway field.  The data
+   portion is an IPv4 address as described in section 3.4.1 of RFC1035
+   [2].  This is a 32-bit number in network byte order.
+
+   A 128-bit IPv6 address is present in the gateway field.  The data
+   portion is an IPv6 address as described in section 2.2 of RFC1886
+   [7].  This is a 128-bit number in network byte order.
+
+   The gateway field is a normal wire-encoded domain name, as described
+   in section 3.3 of RFC1035 [2].  Compression MUST NOT be used.
+
+2.6 RDATA format - public keys
+
+   Both of the public key types defined in this document (RSA and DSA)
+   inherit their public key formats from the corresponding KEY RR
+   formats.  Specifically, the public key field contains the algorithm-
+   specific portion of the KEY RR RDATA, which is all of the KEY RR DATA
+   after the first four octets.  This is the same portion of the KEY RR
+   that must be specified by documents that define a DNSSEC algorithm.
+   Those documents also specify a message digest to be used for
+   generation of SIG RRs; that specification is not relevant for
+   IPSECKEY RR.
+
+   Future algorithms, if they are to be used by both DNSSEC (in the KEY
+   RR) and IPSECKEY, are likely to use the same public key encodings in
+   both records.  Unless otherwise specified, the IPSECKEY public key
+   field will contain the algorithm-specific portion of the KEY RR RDATA
+   for the corresponding algorithm.  The algorithm must still be
+
+
+
+Richardson                Expires March 4, 2004                 [Page 5]
+
+Internet-Draft                   ipsecrr                  September 2003
+
+
+   designated for use by IPSECKEY, and an IPSECKEY algorithm type number
+   (which might be different than the DNSSEC algorithm number) must be
+   assigned to it.
+
+   The DSA key format is defined in RFC2536 [11]
+
+   The RSA key format is defined in RFC3110 [12], with the following
+   changes:
+
+   The earlier definition of RSA/MD5 in RFC2065 limited the exponent and
+   modulus to 2552 bits in length.  RFC3110 extended that limit to 4096
+   bits for RSA/SHA1 keys.  The IPSECKEY RR imposes no length limit on
+   RSA public keys, other than the 65535 octet limit imposed by the two-
+   octet length encoding.  This length extension is applicable only to
+   IPSECKEY and not to KEY RRs.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Richardson                Expires March 4, 2004                 [Page 6]
+
+Internet-Draft                   ipsecrr                  September 2003
+
+
+3. Presentation formats
+
+3.1 Representation of IPSECKEY RRs
+
+   IPSECKEY RRs may appear in a zone data master file.  The precedence,
+   gateway type and algorithm and gateway fields are REQUIRED.  The
+   base64 encoded public key block is OPTIONAL; if not present, then the
+   public key field of the resource record MUST be construed as being
+   zero octets in length.
+
+   The algorithm field is an unsigned integer.  No mnemonics are
+   defined.
+
+   If no gateway is to be indicated, then the gateway type field MUST be
+   zero, and the gateway field MUST be "."
+
+   The Public Key field is represented as a Base64 encoding of the
+   Public Key.  Whitespace is allowed within the Base64 text.  For a
+   definition of Base64 encoding, see RFC1521 [3] Section 5.2.
+
+   The general presentation for the record as as follows:
+
+   IN     IPSECKEY ( precedence gateway-type algorithm
+                     gateway base64-encoded-public-key )
+
+
+3.2 Examples
+
+   An example of a node 192.0.2.38 that will accept IPsec tunnels on its
+   own behalf.
+
+   38.2.0.192.in-addr.arpa. 7200 IN     IPSECKEY ( 10 1 2
+                    192.0.2.38
+                    AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )
+
+   An example of a node, 192.0.2.38 that has published its key only.
+
+   38.2.0.192.in-addr.arpa. 7200 IN     IPSECKEY ( 10 0 2
+                    .
+                    AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )
+
+   An example of a node, 192.0.2.38 that has delegated authority to the
+   node 192.0.2.3.
+
+   38.2.0.192.in-addr.arpa. 7200 IN     IPSECKEY ( 10 1 2
+                    192.0.2.3
+                    AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )
+
+
+
+
+Richardson                Expires March 4, 2004                 [Page 7]
+
+Internet-Draft                   ipsecrr                  September 2003
+
+
+   An example of a node, 192.0.1.38 that has delegated authority to the
+   node with the identity "mygateway.example.com".
+
+   38.1.0.192.in-addr.arpa. 7200 IN     IPSECKEY ( 10 3 2
+                    mygateway.example.com.
+                    AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )
+
+   An example of a node, 2001:0DB8:0200:1:210:f3ff:fe03:4d0 that has
+   delegated authority to the node 2001:0DB8:c000:0200:2::1
+
+   $ORIGIN 1.0.0.0.0.0.2.8.B.D.0.1.0.0.2.ip6.int.
+   0.d.4.0.3.0.e.f.f.f.3.f.0.1.2.0 7200 IN     IPSECKEY ( 10 2 2
+                    2001:0DB8:0:8002::2000:1
+                    AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
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+
+
+
+
+
+
+
+
+
+
+
+
+
+Richardson                Expires March 4, 2004                 [Page 8]
+
+Internet-Draft                   ipsecrr                  September 2003
+
+
+4. Security Considerations
+
+   This entire memo pertains to the provision of public keying material
+   for use by key management protocols such as ISAKMP/IKE (RFC2407) [9].
+
+   The IPSECKEY resource record contains information that SHOULD be
+   communicated to the end client in an integral fashion - i.e.  free
+   from modification.  The form of this channel is up to the consumer of
+   the data - there must be a trust relationship between the end
+   consumer of this resource record and the server.  This relationship
+   may be end-to-end DNSSEC validation, a TSIG or SIG(0) channel to
+   another secure source, a secure local channel on the host, or some
+   combination of the above.
+
+   The keying material provided by the IPSECKEY resource record is not
+   sensitive to passive attacks.  The keying material may be freely
+   disclosed to any party without any impact on the security properties
+   of the resulting IPsec session: IPsec and IKE provide for defense
+   against both active and passive attacks.
+
+   Any user of this resource record MUST carefully document their trust
+   model, and why the trust model of DNSSEC is appropriate, if that is
+   the secure channel used.
+
+4.1 Active attacks against unsecured IPSECKEY resource records
+
+   This section deals with active attacks against the DNS.  These
+   attacks require that DNS requests and responses be intercepted and
+   changed.  DNSSEC is designed to defend against attacks of this kind.
+
+   The first kind of active attack is when the attacker replaces the
+   keying material with either a key under its control or with garbage.
+
+   If the attacker is not able to mount a subsequent man-in-the-middle
+   attack on the IKE negotiation after replacing the public key, then
+   this will result in a denial of service, as the authenticator used by
+   IKE would fail.
+
+   If the attacker is able to both to mount active attacks against DNS
+   and is also in a position to perform a man-in-the-middle attack on
+   IKE and IPsec negotiations, then the attacker will be in a position
+   to compromise the resulting IPsec channel.  Note that an attacker
+   must be able to perform active DNS attacks on both sides of the IKE
+   negotiation in order for this to succeed.
+
+   The second kind of active attack is one in which the attacker
+   replaces the the gateway address to point to a node under the
+   attacker's control.  The attacker can then either replace the public
+
+
+
+Richardson                Expires March 4, 2004                 [Page 9]
+
+Internet-Draft                   ipsecrr                  September 2003
+
+
+   key or remove it, thus providing an IPSECKEY record of its own to
+   match the gateway address.
+
+   This later form creates a simple man-in-the-middle since the attacker
+   can then create a second tunnel to the real destination.  Note that,
+   as before, this requires that the attacker also mount an active
+   attack against the responder.
+
+   Note that the man-in-the-middle can not just forward cleartext
+   packets to the original destination.  While the destination may be
+   willing to speak in the clear, replying to the original sender, the
+   sender will have already created a policy expecting ciphertext.
+   Thus, the attacker will need to intercept traffic from both sides.
+   In some cases, the attacker may be able to accomplish the full
+   intercept by use of Network Addresss/Port Translation (NAT/NAPT)
+   technology.
+
+   Note that the danger here only applies to cases where the gateway
+   field of the IPSECKEY RR indicates a different entity than the owner
+   name of the IPSECKEY RR.  In cases where the end-to-end integrity of
+   the IPSECKEY RR is suspect, the end client MUST restrict its use of
+   the IPSECKEY RR to cases where the RR owner name matches the content
+   of the gateway field.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Richardson                Expires March 4, 2004                [Page 10]
+
+Internet-Draft                   ipsecrr                  September 2003
+
+
+5. IANA Considerations
+
+   This document updates the IANA Registry for DNS Resource Record Types
+   by assigning type X to the IPSECKEY record.
+
+   This document creates an IANA registry for the algorithm type field.
+
+   Values 0, 1 and 2 are defined in Section 2.3.  Algorithm numbers 3
+   through 255 can be assigned by IETF Consensus (see RFC2434 [6]).
+
+   This document creates an IANA registry for the gateway type field.
+
+   Values 0, 1, 2 and 3 are defined in Section 2.4.  Algorithm numbers 4
+   through 255 can be assigned by Standards Action (see RFC2434 [6]).
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
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+
+
+
+
+
+
+
+
+
+Richardson                Expires March 4, 2004                [Page 11]
+
+Internet-Draft                   ipsecrr                  September 2003
+
+
+6. Acknowledgments
+
+   My thanks to Paul Hoffman, Sam Weiler, Jean-Jacques Puig, Rob
+   Austein, and Olafur Gurmundsson who reviewed this document carefully.
+   Additional thanks to Olafur Gurmundsson for a reference
+   implementation.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
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+
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+
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+
+
+
+Richardson                Expires March 4, 2004                [Page 12]
+
+Internet-Draft                   ipsecrr                  September 2003
+
+
+Normative references
+
+   [1]  Mockapetris, P., "Domain names - concepts and facilities", STD
+        13, RFC 1034, November 1987.
+
+   [2]  Mockapetris, P., "Domain names - implementation and
+        specification", STD 13, RFC 1035, November 1987.
+
+   [3]  Borenstein, N. and N. Freed, "MIME (Multipurpose Internet Mail
+        Extensions) Part One: Mechanisms for Specifying and Describing
+        the Format of Internet Message Bodies", RFC 1521, September
+        1993.
+
+   [4]  Bradner, S., "The Internet Standards Process -- Revision 3", BCP
+        9, RFC 2026, October 1996.
+
+   [5]  Eastlake, D. and C. Kaufman, "Domain Name System Security
+        Extensions", RFC 2065, January 1997.
+
+   [6]  Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
+        Considerations Section in RFCs", BCP 26, RFC 2434, October 1998.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
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+
+
+
+
+
+
+
+
+
+Richardson                Expires March 4, 2004                [Page 13]
+
+Internet-Draft                   ipsecrr                  September 2003
+
+
+Non-normative references
+
+   [7]   Thomson, S. and C. Huitema, "DNS Extensions to support IP
+         version 6", RFC 1886, December 1995.
+
+   [8]   Bradner, S., "Key words for use in RFCs to Indicate Requirement
+         Levels", BCP 14, RFC 2119, March 1997.
+
+   [9]   Piper, D., "The Internet IP Security Domain of Interpretation
+         for ISAKMP", RFC 2407, November 1998.
+
+   [10]  Eastlake, D., "Domain Name System Security Extensions", RFC
+         2535, March 1999.
+
+   [11]  Eastlake, D., "DSA KEYs and SIGs in the Domain Name System
+         (DNS)", RFC 2536, March 1999.
+
+   [12]  Eastlake, D., "RSA/SHA-1 SIGs and RSA KEYs in the Domain Name
+         System (DNS)", RFC 3110, May 2001.
+
+   [13]  Massey, D. and S. Rose, "Limiting the Scope of the KEY Resource
+         Record (RR)", RFC 3445, December 2002.
+
+
+Author's Address
+
+   Michael C. Richardson
+   Sandelman Software Works
+   470 Dawson Avenue
+   Ottawa, ON  K1Z 5V7
+   CA
+
+   EMail: mcr@sandelman.ottawa.on.ca
+   URI:   http://www.sandelman.ottawa.on.ca/
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Richardson                Expires March 4, 2004                [Page 14]
+
+Internet-Draft                   ipsecrr                  September 2003
+
+
+Full Copyright Statement
+
+   Copyright (C) The Internet Society (2003).  All Rights Reserved.
+
+   This document and translations of it may be copied and furnished to
+   others, and derivative works that comment on or otherwise explain it
+   or assist in its implementation may be prepared, copied, published
+   and distributed, in whole or in part, without restriction of any
+   kind, provided that the above copyright notice and this paragraph are
+   included on all such copies and derivative works.  However, this
+   document itself may not be modified in any way, such as by removing
+   the copyright notice or references to the Internet Society or other
+   Internet organizations, except as needed for the purpose of
+   developing Internet standards in which case the procedures for
+   copyrights defined in the Internet Standards process must be
+   followed, or as required to translate it into languages other than
+   English.
+
+   The limited permissions granted above are perpetual and will not be
+   revoked by the Internet Society or its successors or assigns.
+
+   This document and the information contained herein is provided on an
+   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
+   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
+   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
+   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
+   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
+
+Acknowledgement
+
+   Funding for the RFC Editor function is currently provided by the
+   Internet Society.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Richardson                Expires March 4, 2004                [Page 15]
+
diff --git a/doc/draft-spencer-ipsec-ike-implementation.nr b/doc/draft-spencer-ipsec-ike-implementation.nr
new file mode 100644
index 000000000..5b5776e22
--- /dev/null
+++ b/doc/draft-spencer-ipsec-ike-implementation.nr
@@ -0,0 +1,1203 @@
+.\" date, expiry date, copyright year, and revision
+.DA "26 Feb 2002"
+.ds e "26 Aug 2002
+.ds c 2002
+.ds r 02
+.\" boilerplate
+.pl 10i
+.nr PL 10i
+.po 0
+.nr PO 0
+.ll 7.2i
+.nr LL 7.2i
+.lt 7.2i
+.nr LT 7.2i
+.hy 0
+.nr HY 0
+.ad l
+.nr PD 1v
+.\" macros for paragraph, section header, reference, TOC
+.de P
+.br
+.LP
+.in 3
+..
+.de H
+.br
+.ne 5
+.LP
+.in 0
+..
+.de R
+.IP "   [\\$1]" 14
+..
+.de T
+.ie \\$1=1 \{\
+.nf
+.ta \n(LLu-3nR
+.\}
+.el \{\
+.fi
+.\}
+..
+.de S
+.ie '\\$1'' \\$2 \a \\$3
+.el \\$1. \\$2 \a \\$3
+..
+.\" headers/footers
+.ds LH "Internet Draft
+.ds CH "IKE Implementation Issues
+.ds RH "\*(DY
+.ds LF "Spencer & Redelmeier
+.ds CF "
+.ds RF "[Page %]
+.\" and let's get started
+.RT
+.nf
+.tl 'Network Working Group''Henry Spencer'
+.tl 'Internet Draft''SP Systems'
+.tl 'Expires: \*e''D. Hugh Redelmeier'
+.tl '''Mimosa Systems'
+.tl '''\*(DY'
+.sp
+.ce 99
+IKE Implementation Issues
+<draft-spencer-ipsec-ike-implementation-\*r.txt>
+.ce 0
+.H
+Status of this Memo
+.P
+This document is an Internet-Draft and is in full conformance with
+all provisions of Section 10 of RFC2026.
+.P
+(If approved as an Informational RFC...)
+This memo provides information for the Internet community.
+This memo does not specify an Internet standard of any kind.
+.P
+Distribution of this memo is unlimited.
+.P
+Internet-Drafts are working documents of the Internet Engineering
+Task Force (IETF), its areas, and its working groups.
+Note that
+other groups may also distribute working documents as Internet-Drafts.
+.P
+Internet-Drafts are draft documents valid for a maximum of six months
+and may be updated, replaced, or obsoleted by other documents at any
+time.
+It is inappropriate to use Internet-Drafts as reference
+material or to cite them other than as "work in progress."
+.P
+The list of current Internet-Drafts can be accessed at
+http://www.ietf.org/ietf/1id-abstracts.txt.
+.P
+The list of Internet-Draft Shadow Directories can be accessed at
+http://www.ietf.org/shadow.html.
+.P
+This Internet-Draft will expire on \*e.
+.H
+Copyright Notice
+.P
+Copyright (C) The Internet Society \*c.  All Rights Reserved.
+.bp
+.H
+Table of Contents
+.P
+.T 1
+.S "1" "Introduction" "3"
+.S "2" "Lower-level Background and Notes" "4"
+.S "2.1" "Packet Handling" "4"
+.S "2.2" "Ciphers" "5"
+.S "2.3" "Interfaces" "5"
+.S "3" "IKE Infrastructural Issues" "5"
+.S "3.1" "Continuous Channel" "5"
+.S "3.2" "Retransmission" "5"
+.S "3.3" "Replay Prevention" "6"
+.S "4" "Basic Keying and Rekeying" "7"
+.S "4.1" "When to Create SAs" "7"
+.S "4.2" "When to Rekey" "8"
+.S "4.3" "Choosing an SA" "9"
+.S "4.4" "Why to Rekey" "9"
+.S "4.5" "Rekeying ISAKMP SAs" "10"
+.S "4.6" "Bulk Negotiation" "10"
+.S "5" "Deletions, Teardowns, Crashes" "11"
+.S "5.1" "Deletions" "11"
+.S "5.2" "Teardowns and Shutdowns" "12"
+.S "5.3" "Crashes" "13"
+.S "5.4" "Network Partitions" "13"
+.S "5.5" "Unknown SAs" "14"
+.S "6" "Misc. IKE Issues" "16"
+.S "6.1" "Groups 1 and 5" "16"
+.S "6.2" "To PFS Or Not To PFS" "16"
+.S "6.3" "Debugging Tools, Lack Thereof" "16"
+.S "6.4" "Terminology, Vagueness Thereof" "17"
+.S "6.5" "A Question of Identity" "17"
+.S "6.6" "Opportunistic Encryption" "17"
+.S "6.7" "Authentication and RSA Keys" "17"
+.S "6.8" "Misc. Snags" "18"
+.S "7" "Security Considerations" "19"
+.S "8" "References" "19"
+.S "" "Authors' Addresses" "20"
+.S "" "Full Copyright Statement" "21"
+.T 0
+.bp
+.H
+Abstract
+.P
+The current IPsec specifications for key exchange and connection management,
+RFCs 2408 [ISAKMP] and 2409 [IKE],
+leave many aspects of connection management unspecified,
+most prominently rekeying practices.
+Pending clarifications in future revisions of the specifications,
+this document sets down some successful experiences,
+to minimize the extent to which new implementors have to rely
+on unwritten folklore.
+.P
+The Linux FreeS/WAN implementation of IPsec interoperates
+with almost every other IPsec implementation.
+This document describes how the FreeS/WAN project has resolved
+some of the gaps in the IPsec specifications
+(and plans to resolve some others),
+and what difficulties have been encountered,
+in hopes that this generally-successful experience
+might be informative to new implementors.
+.P
+This is offered as an Informational RFC.
+.P
+This -\*r revision mainly:
+discusses ISAKMP SA expiry during IPsec-SA rekeying (4.5),
+revises the discussion of bidirectional Deletes (5.1),
+suggests remembering the parameters of successful negotiations
+for later use (4.2, 5.3),
+notes an unsuccessful negotiation from the other end as a hint of a possibly
+broken connection (5.5),
+and adds sections on network partitions (5.4),
+authentication methods and the subtleties of RSA public keys (6.7),
+and miscellaneous interoperability concerns (6.8).
+.H
+1. Introduction
+.P
+The current IPsec specifications for key exchange and connection management,
+RFCs 2408 [ISAKMP] and 2409 [IKE],
+leave many aspects of connection management unspecified,
+most prominently rekeying practices.
+This is a cryptic puzzle which
+each group of implementors has to struggle with,
+and differences in how the ambiguities and gaps are resolved are
+potentially a fruitful source of interoperability problems.
+We can hope that future revisions of the specifications will clear this up.
+Meanwhile, it seems useful to set down some successful experiences,
+to minimize the extent to which new implementors have to rely
+on unwritten folklore.
+.P
+The Linux FreeS/WAN implementation of IPsec interoperates
+with almost every other IPsec implementation,
+and because of its free nature,
+it also sees some use as a reference implementation by other implementors.
+The high degree of interoperability is noteworthy
+given its organizers' strong minimalist bias,
+which has caused them to implement only
+a small subset of the full glory of IPsec.
+This document describes how the FreeS/WAN project has resolved
+some of the gaps in the IPsec specifications
+(and plans to resolve some others),
+and what difficulties have been encountered,
+in hopes that this generally-successful experience
+might be informative to new implementors.
+.P
+One small caution about applicability:
+this experience may not be relevant
+to severely resource-constrained implementations.
+FreeS/WAN's target environment is previous-generation PCs,
+now available at trivial cost (often,
+within an organization, at no cost),
+which have quite impressive CPU power and memory by the standards
+of only a few years ago.
+Some of the approaches discussed here may be inapplicable to
+implementations with severe external constraints which prevent them
+from taking advantage of modern hardware technology.
+.H
+2. Lower-level Background and Notes
+.H
+2.1. Packet Handling
+.P
+FreeS/WAN implements ESP [ESP] and AH [AH] straightforwardly,
+although AH sees little use among our users.
+Our ESP/AH implementation cannot currently handle packets
+with IP options;
+somewhat surprisingly, this has caused little difficulty.
+We insist on encryption and do not support authentication-only
+connections, and this has not caused significant difficulty either.
+.P
+MTU and fragmentation issues, by contrast, have been a constant headache.
+We will not describe the details of our current approach to them,
+because it still needs work.
+One difficulty we have encountered is that many combinations of
+packet source and packet destination
+apparently cannot cope with an "interior minimum" in the path MTU,
+e.g. where an IPsec tunnel intervenes and its headers reduce the MTU
+for an intermediate link.
+This is particularly prevalent when using common PC software to
+connect to large well-known web sites;
+we think it is largely due to
+misconfigured firewalls which do not pass ICMP
+Fragmentation Required messages.
+The only solution we have yet found is to lie about the MTU of the tunnel,
+accepting the (undesirable) fragmentation of the ESP packets
+for the sake of preserving connectivity.
+.P
+We currently zero out the TOS field of ESP packets,
+rather than copying it from the inner header,
+on the grounds that it lends itself too well to traffic analysis
+and covert channels.
+We provide an option to restore RFC 2401 [IPSEC] copying behavior,
+but this appears to see little use.
+.H
+2.2. Ciphers
+.P
+We initially implemented both DES [DES] and 3DES [CIPHERS] for both
+IKE and ESP,
+but after the Deep Crack effort [CRACK] demonstrated its inherent insecurity,
+we dropped support for DES.
+Somewhat surprisingly,
+our insistence on 3DES has caused almost no interoperability problems,
+despite DES being officially mandatory.
+A very few other systems either do not support 3DES or support it only
+as an optional upgrade,
+which inconveniences a few would-be users.
+There have also been one or two cases of systems
+which don't quite seem to know the difference!
+.P
+See also section 6.1 for a consequence of our insistence on 3DES.
+.H
+2.3. Interfaces
+.P
+We currently employ PF_KEY version 2 [PFKEY],
+plus various non-standard extensions,
+as our interface between keying and ESP.
+This has not proven entirely satisfactory.
+Our feeling now is that keying issues and policy issues
+do not really lend
+themselves to the clean separation that PF_KEY envisions.
+.H
+3. IKE Infrastructural Issues
+.P
+A number of problems in IPsec connection management become easier if
+some attention is first paid to providing an infrastructure
+to support solving them.
+.H
+3.1. Continuous Channel
+.P
+FreeS/WAN uses an approximation to the "continuous channel" model,
+in which ISAKMP SAs are maintained between IKEs
+so long as any IPsec SAs are open between the two systems.
+The resource consumption of this is minor:
+the only substantial overhead is occasional rekeying.
+IPsec SA management becomes significantly simpler if there is always
+a channel for transmission of control messages.
+We suggest (although we do not yet fully implement this) that
+inability to maintain (e.g., to rekey) this control path
+should be grounds for tearing down the IPsec SAs as well.
+.P
+As a corollary of this,
+there is one and only one ISAKMP SA maintained between a pair of IKEs
+(although see sections 5.3 and 6.5 for minor complications).
+.H
+3.2. Retransmission
+.P
+The unreliable nature of UDP transmission is a nuisance.
+IKE implementations should always be prepared to retransmit the most recent
+message they sent on an ISAKMP SA,
+since there is some possibility that the other end did not get it.
+This means, in particular,
+that the system sending the supposedly-last message of an exchange
+cannot relax and assume that the exchange is complete,
+at least not until a significant timeout has elapsed.
+.P
+Systems must also retain information about the message most recently received
+in an exchange,
+so that a duplicate of it can be detected
+(and possibly interpreted as a NACK for the response).
+.P
+The retransmission rules FreeS/WAN follows are:
+(1) if a reply is expected, retransmit only if it does not appear
+before a timeout;
+and (2) if a reply is not expected (last message of the exchange),
+retransmit only on receiving a retransmission of the previous message.
+Notably, in case (1) we do NOT retransmit on receiving a retransmission,
+which avoids possible congestion problems arising from packet duplication,
+at the price of slowing response to packet loss.
+The timeout for case (1) is 10 seconds for the first retry,
+20 seconds for the second, and 40 seconds for all subsequent
+retries (normally only one,
+except when
+configuration settings call for persistence and the message is
+the first message of Main Mode with a new peer).
+These retransmission rules have been entirely successful.
+.P
+(Michael Thomas of Cisco has pointed out that the retry timeouts should
+include some random jitter, to de-synchronize hosts which are
+initially synchronized by, e.g., a power outage.
+We already jitter our rekeying times,
+as noted in section 4.2,
+but that does not help with initial startup.
+We're implementing jittered retries,
+but cannot yet report on experience with this.)
+.P
+There is a deeper problem, of course, when an entire "exchange" consists
+of a single message,
+e.g. the ISAKMP Informational Exchange.
+Then there is no way to decide whether or when a retransmission is
+warranted at all.
+This seems like poor design, to put it mildly
+(and there is now talk of fixing it).
+We have no experience in dealing with this problem at this time,
+although it is part of the reason why we have delayed implementing
+Notification messages.
+.H
+3.3. Replay Prevention
+.P
+The unsequenced nature of UDP transmission is also troublesome,
+because it means that higher levels must consider the possibility
+of replay attacks.
+FreeS/WAN takes the position that systematically eliminating this
+possibility at a low level is strongly preferable to forcing careful
+consideration of possible impacts at every step of an exchange.
+RFC 2408 [ISAKMP] section 3.1 states that the Message ID of an
+ISAKMP message must be "unique".
+FreeS/WAN interprets this literally,
+as forbidding duplication of Message IDs
+within the set of all messages sent via a single ISAKMP SA.
+.P
+This requires remembering all Message IDs until the ISAKMP SA is
+superseded by rekeying,
+but that is not costly (four bytes per sent or received message),
+and it ELIMINATES replay attacks from consideration;
+we believe this investment of resources is well worthwhile.
+If the resource consumption becomes excessive\(emin our experience
+it has not\(emthe ISAKMP SA can be rekeyed early to collect the garbage.
+.P
+There is theoretically an interoperability problem when talking to
+implementations which interpret "unique" more loosely
+and may re-use Message IDs,
+but it has not been encountered in practice.
+This approach appears to be completely interoperable.
+.P
+The proposal by
+Andrew Krywaniuk [REPLAY],
+which advocates turning the Message ID into an anti-replay counter,
+would achieve the same goal without the minor per-message memory overhead.
+This may be preferable,
+although it means an actual protocol change and more study is needed.
+.H
+4. Basic Keying and Rekeying
+.H
+4.1. When to Create SAs
+.P
+As Tim Jenkins [REKEY] pointed out,
+there is a potential race condition in Quick Mode:
+a fast lightly-loaded Initiator might start using IPsec SAs very
+shortly after sending QM3 (the third and last message of Quick Mode),
+while a slow heavily-loaded Responder might
+not be ready to receive them until after spending
+a significant amount of time creating its inbound SAs.
+The problem is even worse if QM3 gets delayed or lost.
+.P
+FreeS/WAN's approach to this is what Jenkins called "Responder Pre-Setup":
+the Responder creates its inbound IPsec SAs before it sends QM2,
+so they are always ready and waiting
+when the Initiator sends QM3 and begins sending traffic.
+This approach is simple and reliable,
+and in our experience it interoperates with everybody.
+(There is potentially still a problem if FreeS/WAN is the Initiator
+and the Responder does not use Responder Pre-Setup,
+but no such problems have been seen.)
+The only real weakness of Responder Pre-Setup
+is the possibility of replay attacks,
+which we have eliminated by other means (see section 3.3).
+.P
+With this approach, the Commit Bit is useless,
+and we ignore it.
+In fact, until quite recently we discarded any IKE message containing it,
+and this caused surprisingly few interoperability problems;
+apparently it is not widely used.
+We have recently been persuaded that simply ignoring it is preferable;
+preliminary experience with this indicates that the result is successful
+interoperation with implementations which set it.
+.H
+4.2. When to Rekey
+.P
+To preserve connectivity for user traffic,
+rekeying of a connection
+(that is, creation of new IPsec SAs to supersede the current ones)
+must begin before its current IPsec SAs expire.
+Preferably one end should predictably start rekeying negotiations first,
+to avoid the extra overhead of two simultaneous negotiations,
+although either end should be prepared to rekey if the other does not.
+There is also a problem with "convoys" of keying negotiations:
+for example, a "hub" gateway with many IPsec connections
+can be inundated with rekeying negotiations
+exactly one connection-expiry time after it reboots,
+and the massive overload this induces tends to make this
+situation self-perpetuating,
+so it recurs regularly.
+(Convoys can also evolve gradually from initially-unsynchronized negotiations.)
+.P
+FreeS/WAN has the concept of a "rekeying margin", measured in seconds.
+If FreeS/WAN was the Initiator for the previous rekeying
+(or the startup, if none) of the connection,
+it nominally starts rekeying negotiations at expiry time
+minus one rekeying margin.
+Some random jitter is added to break up convoys:
+rather than starting rekeying exactly at minus one margin,
+it starts at a random time between minus one margin
+and minus two margins.
+(The randomness here need not be cryptographic in quality,
+so long as it varies over time and between hosts.
+We use an ordinary PRNG seeded with a few bytes from a cryptographic
+randomness source.
+The seeding mostly just ensures that the PRNG sequence is different
+for different hosts, even if they start up simultaneously.)
+.P
+If FreeS/WAN was the Responder for the previous rekeying/startup,
+and nothing has been heard from the previous Initiator
+at expiry time minus one-half the rekeying margin,
+FreeS/WAN will initiate rekeying negotiations.
+No jitter is applied;
+we now believe that it should be jittered,
+say between minus one-half margin and minus one-quarter margin.
+.P
+Having the Initiator lead the way is an obvious way of deciding
+who should speak first,
+since there is already an Initiator/Responder asymmetry in the connection.
+Moreover, our experience has been that Initiator lead gives a significantly
+higher probability of successful negotiation!
+The negotiation process itself is asymmetric,
+because the Initiator must make a few specific proposals which the Responder
+can only accept or reject,
+so the Initiator must try to guess where its "acceptable" region
+(in parameter space)
+might overlap with the Responder's.
+We have seen situations where negotiations would succeed or fail
+depending on which end initiated them,
+because one end was making better guesses.
+Given an existing connection,
+we KNOW that the previous Initiator WAS able to initiate a successful
+negotiation,
+so it should (if at all possible) take the lead again.
+Also, the Responder should remember the Initiator's successful proposal,
+and start from that
+rather than from his own default proposals if he must take the lead;
+we don't currently implement this completely but plan to.
+.P
+FreeS/WAN defaults the rekeying margin to 9 minutes,
+although this can be changed by configuration.
+There is also
+a configuration option to alter the permissible range of jitter.
+The defaults were chosen somewhat arbitrarily,
+but they work extremely well
+and the configuration options are rarely used.
+.H
+4.3. Choosing an SA
+.P
+Once rekeying has occurred,
+both old and new IPsec SAs for the connection exist,
+at least momentarily.
+FreeS/WAN accepts incoming traffic
+on either old or new inbound SAs,
+but sends outgoing traffic only on the new outbound ones.
+This approach appears to be significantly more robust than
+using the old ones until they expire,
+notably in cases where renegotiation has occurred because something has
+gone wrong on the other end.
+It avoids having to pay meticulous attention to the state of the other end,
+state which is difficult to learn reliably given the limitations of IKE.
+.P
+This approach has interoperated successfully with ALMOST all other
+implementations.
+The only (well-characterized) problem cases have been implementations
+which rely on receiving a Delete message for the old SAs to tell them
+to switch over to the new ones.
+Since delivery of Delete is unreliable,
+and support for Delete is optional,
+this reliance seems like a serious mistake.
+This is all the more true because Delete
+announces that the deletion has
+already occurred [ISAKMP, section 3.15], not that it is about to occur,
+so packets already in transit in the other direction could be lost.
+Delete should be used for resource cleanup, not for switchover control.
+(These matters are discussed further in section 5.)
+.H
+4.4. Why to Rekey
+.P
+FreeS/WAN currently implements only time-based expiry (life in seconds),
+although we are working toward
+supporting volume-based expiry (life in kilobytes) as well.
+The lack of volume-based expiry has not been an interoperability
+problem so far.
+.P
+Volume-based expiry does add some minor complications.
+In particular, it makes explicit Delete of now-disused SAs more important,
+because once an SA stops being used,
+it might not expire on its own.
+We believe this lacks robustness and is generally unwise,
+especially given the lack of a reliable Delete,
+and expect to use volume-based expiry only as a supplement
+to time-based expiry.
+However, Delete support (see section 5) does seem advisable
+for use with volume-based expiry.
+.P
+We do not believe that volume-based expiry alters the desirability
+of switching immediately to the new SAs after rekeying.
+Rekeying margins are normally a small fraction of the total life of an SA,
+so we feel there is no great need to "use it all up".
+.H
+4.5. Rekeying ISAKMP SAs
+.P
+The above discussion has focused on rekeying for IPsec SAs,
+but FreeS/WAN applies the same approaches to rekeying for ISAKMP SAs,
+with similar success.
+.P
+One issue which we have noticed, but not explicitly dealt with,
+is that difficulties may ensue if an IPsec-SA rekeying negotiation
+is in progress at the time when the relevant ISAKMP SA gets rekeyed.
+The IKE specification [IKE] hints, but does not actually say,
+that a Quick Mode negotiation should remain on a single ISAKMP SA throughout.
+.P
+A reasonable rekeying margin will generally
+prevent the old ISAKMP SA from actually expiring during a negotiation.
+Some attention may be needed to prevent in-progress negotiations from
+being switched to the new ISAKMP SA.
+Any attempt at pre-expiry deletion of the ISAKMP SA must be postponed
+until after such dangling negotiations are completed,
+and there should be enough delay between ISAKMP-SA rekeying and a
+deletion attempt to (more or less)
+ensure that there are no negotiation-starting packets still in transit
+from before the rekeying.
+.P
+At present, FreeS/WAN does none of this,
+and we don't KNOW of any resulting trouble.
+With normal lifetimes, the problem should be uncommon,
+and we speculate that an occasional disrupted negotiation simply gets retried.
+.H
+4.6. Bulk Negotiation
+.P
+Quick Mode nominally provides for negotiating possibly-large numbers of
+similar but unrelated IPsec SAs simultaneously
+[IKE, section 9].
+Nobody appears to do this.
+FreeS/WAN does not support it, and its absence has caused no problems.
+.H
+5. Deletions, Teardowns, Crashes
+.P
+FreeS/WAN currently ignores all Notifications and Deletes,
+and never generates them.
+This has caused little difficulty in interoperability,
+which shouldn't be surprising (since Notification and Delete support is
+officially entirely optional) but does seem to surprise some people.
+Nevertheless, we do plan some changes to this approach
+based on past experience.
+.H
+5.1. Deletions
+.P
+As hinted at above,
+we plan to implement Delete support, done as follows.
+Shortly after rekeying of IPsec SAs,
+the Responder issues a Delete for its old inbound SAs
+(but does not actually delete them yet).
+The Responder initiates this because the Initiator started using the
+new SAs on sending QM3, while the Responder started using them only
+on (or somewhat after) receiving QM3,
+so there is less chance of old-SA packets still being in transit from
+the Initiator.
+The Initiator issues an unsolicited Delete only if it does not hear one
+from the Responder after a longer delay.
+.P
+Either party, on receiving a Delete
+for one or more of the old outbound SAs of a connection,
+deletes ALL the connection's SAs,
+and acknowledges with a Delete for the old inbound SAs.
+A Delete for nonexistent SAs
+(e.g., SAs which have already been expired or deleted) is ignored.
+There is no retransmission of unacknowledged Deletes.
+.P
+In the normal case,
+with prompt reliable transmission (except possibly for loss of the
+Responder's initial Delete)
+and conforming implementations
+on both ends, this results in three Deletes being transmitted,
+resembling the classic three-way handshake.
+Loss of a Delete after the first, or multiple losses,
+will cause the SAs not to be deleted on at least one end.
+It appears difficult to do much better without at least
+a distinction between request and acknowledgement.
+.P
+RFC 2409 section 9 "strongly suggests" that there be no response to
+informational messages such as Deletes,
+but the only rationale offered is prevention of infinite loops
+endlessly exchanging "I don't understand you" informationals.
+Since Deletes cannot lead to such a loop
+(and in any case, the nonexistent-SA rule prevents more than one
+acknowledgement for the same connection),
+we believe this recommendation is inapplicable here.
+.P
+As noted in section 4.3, these Deletes are intended for
+resource cleanup, not to control switching between SAs.
+But we expect that they will improve interoperability
+with some broken implementations.
+.P
+We believe strongly that connections need to be considered as a whole,
+rather than treating each SA as an independent entity.
+We will issue Deletes only for the full set of inbound SAs of
+a connection,
+and will treat a Delete for any outbound SA as equivalent to deletion
+of all the outbound SAs for the associated connection.
+.P
+The above is phrased in terms of IPsec SAs,
+but essentially the same approach can be applied to ISAKMP SAs
+(the Deletes for the old ISAKMP SA should be sent via the new one).
+.H
+5.2. Teardowns and Shutdowns
+.P
+When a connection is not intended to be up permanently,
+there is a need to coordinate teardown,
+so that both ends are aware that the connection is down.
+This is both for recovery of resources,
+and to avoid routing packets through
+dangling SAs which can no longer deliver them.
+.P
+Connection teardown will use the same bidirectional exchange of Deletes
+as discussed in section 5.1:
+a Delete received for current IPsec SAs (not yet obsoleted by rekeying)
+indicates that the other host wishes to tear down the associated connection.
+.P
+A Delete received for a current ISAKMP SA indicates that the other host
+wishes to tear down not only the ISAKMP SA but also all IPsec SAs
+currently under the supervision of that ISAKMP SA.
+The 5.1 bidirectional exchange might seem impossible in this case,
+since reception of an ISAKMP-SA Delete indicates that the other end
+will ignore further traffic on that ISAKMP SA.
+We suggest using the same tactic discussed in 5.1 for IPsec SAs:
+the first Delete is sent without actually doing the deletion,
+and the response to receiving a Delete is to do the deletion and reply
+with another Delete.
+If there is no response to the first Delete,
+retry a small number of times and then give up and do the deletion;
+apart from being robust against packet loss,
+this also maximizes the probability that an implementation which does
+not do the bidirectional Delete will receive at least one of the Deletes.
+.P
+When a host with current connections knows that it is about to shut down,
+it will issue Deletes for all SAs involved (both IPsec and ISAKMP),
+advising its peers (as per the meaning of Delete [ISAKMP, section 3.15])
+that the SAs have become useless.
+It will ignore attempts at rekeying or connection startup thereafter,
+until it shuts down.
+.P
+It would be better to have a Final-Contact notification,
+analogous to Initial-Contact but indicating that no new negotiations
+should be attempted until further notice.
+Initial-Contact actually could be used for shutdown notification (!),
+but in networks where connections are intended to exist permanently,
+it seems likely to provoke unwanted attempts
+to renegotiate the lost connections.
+.H
+5.3. Crashes
+.P
+Systems sometimes crash.
+Coping with the resulting loss of information is easily the most
+difficult problem we have found in implementing robust IPsec systems.
+.P
+When connections are intended to be permanent,
+it is simple to specify renegotiation on reboot.
+With our approach to SA selection (see section 4.3),
+this handles such cases robustly and well.
+We do have to tell users that BOTH hosts should be set this way.
+In cases where crashes are synchronized (e.g. by power interruptions),
+this may result in simultaneous negotiations at reboot.
+We currently allow both negotiations to proceed to completion,
+but our use-newest selection method
+effectively ignores one connection or the other,
+and when one of them rekeys,
+we notice that the new SAs replace those of both old connections,
+and we then refrain from rekeying the other.
+(This duplicate detection is desirable in any event, for robustness,
+to ensure that the system converges on a reasonable state eventually
+after it is perturbed by difficulties or bugs.)
+.P
+When connections are not permanent, the situation is less happy.
+One particular situation in which we see problems is when a number of
+"Road Warrior" hosts occasionally call in to a central server.
+The server is normally configured not to initiate such connections,
+since it does not know when the Road Warrior is available (or what IP
+address it is using).
+Unfortunately, if the server crashes and reboots,
+any Road Warriors then connected have a problem:
+they don't know that the server has crashed,
+so they can't renegotiate,
+and the server has forgotten both the connections and
+their (transient) IP addresses,
+so it cannot renegotiate.
+.P
+We believe that the simplest answer to this problem is what John Denker
+has dubbed "address inertia":
+the server makes a best-effort attempt to remember (in nonvolatile storage)
+which connections were active and what the far-end addresses were
+(and what the successful proposal's parameters were),
+so that it can attempt renegotiation on reboot.
+We have not implemented this yet, but intend to;
+Denker has implemented it himself,
+although in a somewhat messy way,
+and reports excellent results.
+.H
+5.4. Network Partitions
+.P
+A network partition, making the two ends unable to reach each other,
+has many of the same characteristics as having the other end crash... until
+the network reconnects.
+It is desirable that recovery from this be automatic.
+.P
+If the network reconnects before any rekeying attempts
+or other IKE activities occurred,
+recovery is fully transparent,
+because the IKEs have no idea that there was any problem.
+(Complaints such as ICMP Host Unreachable messages are unauthenticated
+and hence cannot be given much weight.)
+This fits the general mold of TCP/IP:
+if nobody wanted to send any traffic, a network outage doesn't matter.
+.P
+If IKE activity did occur,
+the IKE implementation will discover that the other end doesn't seem
+to be responding.
+The preferred response to this depends on the nature of the connection.
+If it was intended to be ephemeral (e.g. opportunistic encryption [OE]),
+closing it down after a few retries is reasonable.
+If the other end is expected to sometimes drop the connection without
+warning, it may not be desirable to retry at all.
+(We support both these forms of configurability,
+and indeed we also have a configuration option to suppress
+rekeying entirely on one end.)
+.P
+If the connection was intended to be permanent, however,
+then persistent attempts to re-establish it are appropriate.
+Some degree of backoff is appropriate here,
+so that retries get less frequent as the outage gets prolonged.
+Backoff should be limited,
+so that re-established connectivity is not followed by a long delay
+before a retry.
+Finally, after many retries (say 24 hours' worth),
+it may be preferable to just declare the connection down and rely
+on manual intervention to re-establish it,
+should this be desirable.
+We do not yet fully support all this.
+.H
+5.5. Unknown SAs
+.P
+A more complete solution to crashes
+would be for an IPsec host to note the arrival
+of ESP packets on an unknown IPsec SA,
+and report it somehow to the other host, which can then decide to renegotiate.
+This arguably might be preferable in any case\(emif
+the non-rebooted host has no traffic to send,
+it does not care whether the connection is intact\(embut
+delays and packet loss will be reduced
+if the connection is renegotiated BEFORE there is traffic for it.
+So unknown-SA detection is best reserved as a fallback method,
+with address inertia used to deal with most such cases.
+.P
+A difficulty with unknown-SA detection is,
+just HOW should the other host be notified?
+IKE provides no good way to do the notification:
+Notification payloads (e.g., Initial-Contact) are unauthenticated
+unless they are sent under protection of an ISAKMP SA.
+A "Security Failures - Bad SPI" ICMP message [SECFAIL]
+is an interesting alternative,
+but has the disadvantage of likewise being unauthenticated.
+It's fundamentally unlikely that there is a simple solution to this,
+given that almost any way of arranging or checking authentication for such a
+notification is costly.
+.P
+We think the best answer to this is a two-step approach.
+An unauthenticated Initial-Contact or
+Security Failures - Bad SPI cannot be taken as a reliable
+report of a problem,
+but can be taken as a hint that a problem MIGHT exist.
+Then there needs to be some reliable way of checking such hints,
+subject to rate limiting since the checks are likely to be costly
+(and checking the same connection repeatedly at short intervals is unlikely
+to be worthwhile anyway).
+So the rebooted host sends the notification,
+and the non-rebooted host\(emwhich still thinks it has a connection\(emchecks
+whether the connection still works,
+and renegotiates if not.
+.P
+Also, if an IPsec host which believes it has a connection to another host
+sees an unsuccessful attempt by that host to negotiate a new one,
+that is also a hint of possible problems,
+justifying a check and possible renegotiation.
+("Unsuccessful" here means a negotiation failure due to lack of a
+satisfactory proposal.
+A failure due to authentication failure
+suggests a denial-of-service attack by a third party,
+rather than a genuine problem on the legitimate other end.)
+As noted in section 4.2,
+it is possible for negotiations to succeed or fail based on which
+end initiates them, and some robustness against that is desirable.
+.P
+We have not yet decided what form the notification should take.
+IKE Initial-Contact is an obvious possibility,
+but has some disadvantages.
+It does not specify which connection has had difficulties.
+Also, the specification [IKE section 4.6.3.3]
+refers to "remote system" and "sending system"
+without clearly specifying just what "system" means;
+in the case of a multi-homed host using multiple forms of identification,
+the question is not trivial.
+Initial-Contact does have the fairly-decisive advantage
+that it is likely to convey the right general
+meaning even to an implementation which does not do things
+exactly the way ours does.
+.P
+A more fundamental difficulty is what form the reliable check takes.
+What is wanted is an "IKE ping",
+verifying that the ISAKMP SA is still intact
+(it being unlikely that IPsec SAs have been lost while the ISAKMP SA has not).
+The lack of such a facility is a serious failing of IKE.
+An acknowledged Notification of some sort would be ideal,
+but there is none at present.
+Some existing implementations are known
+to use the private Notification values 30000 as ping
+and 30002 as ping reply,
+and that seems the most attractive choice at present.
+If it is not recognized, there will probably be no reply,
+and the result will be an unnecessary renegotiation,
+so this needs strict rate limiting.
+(Also, when a new connection is set up,
+it's probably worth determining by experiment whether the other end
+supports IKE ping, and remembering that.)
+.P
+While we think this facility is desirable,
+and is about the best that can be done with the poor tools available,
+we have not gotten very far in implementation and cannot comment
+intelligently about how well it works or interoperates.
+.H
+6. Misc. IKE Issues
+.H
+6.1. Groups 1 and 5
+.P
+We have dropped support for the first Oakley Group (group 1),
+despite it being officially mandatory,
+on the grounds that it is
+grossly too weak to provide enough randomness for 3DES.
+There have been some interoperability problems,
+mostly quite minor:
+ALMOST everyone supports group 2 as well,
+although sometimes it has to be explicitly configured.
+.P
+We also support the quasi-standard group 5 [GROUPS].
+This has not been seriously exercised yet,
+because historically
+we offered group 2 first and almost everyone accepted it.
+We have recently changed to offering group 5 first,
+and no difficulties have been reported.
+.H
+6.2. To PFS Or Not To PFS
+.P
+A persistent small interoperability problem is that
+the presence or absence of PFS (for keys [IKE, section 5.5])
+is neither negotiated nor announced.
+We have it enabled by default,
+and successful interoperation often requires having
+the other end turn it on in their implementation,
+or having the FreeS/WAN end disable it.
+Almost everyone supports it, but it's usually not the default,
+and interoperability is often impossible unless the two ends
+somehow reach prior agreement on it.
+.P
+We do not explicitly support the other flavor of PFS,
+for identities [IKE, section 8],
+and this has caused no interoperability problems.
+.H
+6.3. Debugging Tools, Lack Thereof
+.P
+We find IKE lacking in basic debugging tools.
+Section 5.4, above,
+notes that an IKE ping would be useful for connectivity verification.
+It would also be extremely helpful for determining that UDP/500
+packets get back and forth successfully between the two ends,
+which is often an important first step in debugging.
+.P
+It's also quite common to have IKE negotiate a connection successfully,
+but to have some firewall along the way blocking ESP.
+Users find this mysterious and difficult to diagnose.
+We have no immediate suggestions on what could be done about it.
+.H
+6.4. Terminology, Vagueness Thereof
+.P
+The terminology of IPsec needs work.
+We feel that both the specifications and user-oriented
+documentation would be greatly clarified by concise, intelligible names for
+certain concepts.
+.P
+We semi-consistently use "group" for the set of IPsec SAs which are
+established in one direction
+by a single Quick Mode negotiation and are used together
+to process a packet (e.g., an ESP SA plus an AH SA),
+"connection" for the logical packet path provided
+by a succession of pairs of groups
+(each rekeying providing a new pair, one group in each direction),
+and "keying channel" for the corresponding supervisory path provided
+by a sequence of ISAKMP SAs.
+.P
+We think it's a botch that "PFS" is used to refer to two very different things,
+but we have no specific new terms to suggest, since we only implement
+one kind of PFS and thus can just ignore the other.
+.H
+6.5. A Question of Identity
+.P
+One specification problem deserves note:
+exactly when can an existing phase 1 negotiation
+be re-used for a new phase 2 negotiation,
+as IKE [IKE, section 4] specifies?
+Presumably,
+when it connects the same two "parties"... but exactly what is a "party"?
+.P
+As noted in section 5.4,
+in cases involving multi-homing and multiple identities,
+it's not clear exactly what criteria are used for deciding
+whether the intended far end for a new negotiation is the same one
+as for a previous negotiation.
+Is it by Identification Payload?
+By IP address?
+Or what?
+.P
+We currently use a somewhat-vague notion of "identity",
+basically what gets sent in Identification Payloads,
+for this, and this seems to be successful,
+but we think this needs better specification.
+.H
+6.6. Opportunistic Encryption
+.P
+Further IKE challenges appear in the context of Opportunistic Encryption
+[OE],
+but operational experience with it is too limited as yet for us
+to comment usefully right now.
+.H
+6.7. Authentication and RSA Keys
+.P
+We provide two IKE authentication methods:
+shared secrets ("pre-shared keys")
+and RSA digital signatures.
+(A user-provided add-on package generalizes the latter to limited
+support for certificates;
+we have not worked extensively with it ourselves yet and cannot comment
+on it yet.)
+.P
+Shared secrets, despite their administrative difficulties,
+see considerable use,
+and are also the method of last resort for interoperability problems.
+.P
+For digital signatures,
+we have taken the somewhat unorthodox approach of using "bare" RSA public keys,
+either supplied in configuration files or fetched from DNS,
+rather than getting involved in the complexity of certificates.
+We encode our RSA public keys using the DNS KEY encoding [DNSRSA]
+(aka "RFC 2537", although that RFC is now outdated),
+which has given us no difficulties and which we highly recommend.
+We have seen two difficulties in connection with RSA keys, however.
+.P
+First,
+while a number of IPsec implementations are able to take "bare" RSA public keys,
+each one seems to have its own idea of what format should be used
+for transporting them.
+We've had little success with interoperability here,
+mostly because of key-format issues;
+the implementations generally WILL interoperate successfully if you can
+somehow get an RSA key into them at all, but that's hard.
+X.509 certificates seem to be the lowest (!)
+common denominator for key transfer.
+.P
+Second,
+although the content of RSA public keys has been stable,
+there has been a small but subtle change over time in the content
+of RSA private keys.
+The "internal modulus",
+used to compute the private exponent "d" from the public exponent "e"
+(or vice-versa)
+was originally [RSA] [PKCS1v1] [SCHNEIER] specified to be (p-1)*(q-1),
+where p and q are the two primes.
+However, more recent definitions [PKCS1v2] call it
+"lambda(n)" and define it to be lcm(p-1,\ q-1);
+this appears to be a minor optimization.
+The result is that private keys generated with the new definition
+often fail consistency checks in implementations using the old definition.
+Fortunately, it is seldom necessary to move private keys around.
+Our software now consistently uses the new definition
+(and thus will accept keys generated with either definition),
+but our key generator also has an option to generate old-definition keys,
+for the benefit of users who upgrade their networks incrementally.
+.H
+6.8. Misc. Snags
+.P
+Nonce size is another characteristic that is neither negotiated nor announced
+but that the two ends must somehow be able to agree on.
+Our software accepts anything between 8 and 256, and defaults to 16.
+These numbers were chosen rather arbitrarily,
+but we have seen no interoperability failures here.
+.P
+Nothing in the ISAKMP [ISAKMP] or IKE [IKE] specifications says
+explicitly that a normal Message ID must be non-zero,
+but a zero Message ID in fact causes failures.
+.P
+Similarly, there is nothing in the specs which says that ISAKMP cookies
+must be non-zero, but zero cookies will in fact cause trouble.
+.H
+7. Security Considerations
+.P
+Since this document discusses aspects of building robust and
+interoperable IPsec implementations,
+security considerations permeate it.
+.H
+8. References
+.R AH
+Kent, S., and Atkinson, R.,
+"IP Authentication Header",
+RFC 2402,
+Nov 1998.
+.R CIPHERS
+Pereira, R., and Adams, R.,
+"The ESP CBC-Mode Cipher Algorithms",
+RFC 2451,
+Nov 1998.
+.R CRACK
+Electronic Frontier Foundation,
+"Cracking DES:
+Secrets of Encryption Research, Wiretap Politics and Chip Design",
+O'Reilly 1998,
+ISBN 1-56592-520-3.
+.R DES
+Madson, C., and Doraswamy, N.,
+"The ESP DES-CBC Cipher Algorithm",
+RFC 2405,
+Nov 1998.
+.R DNSRSA
+D. Eastlake 3rd,
+"RSA/SHA-1 SIGs and RSA KEYs in the Domain Name System (DNS)",
+RFC 3110,
+May 2001.
+.R ESP
+Kent, S., and Atkinson, R.,
+"IP Encapsulating Security Payload (ESP)",
+RFC 2406,
+Nov 1998.
+.R GROUPS
+Kivinen, T., and Kojo, M.,
+"More MODP Diffie-Hellman groups for IKE",
+<draft-ietf-ipsec-ike-modp-groups-04.txt>,
+13 Dec 2001 (work in progress).
+.R IKE
+Harkins, D., and Carrel, D.,
+"The Internet Key Exchange (IKE)",
+RFC 2409, Nov 1998.
+.R IPSEC
+Kent, S., and Atkinson, R.,
+"Security Architecture for the Internet Protocol",
+RFC 2401, Nov 1998.
+.R ISAKMP
+Maughan, D., Schertler, M., Schneider, M., and Turner, J.,
+"Internet Security Association and Key Management Protocol (ISAKMP)",
+RFC 2408, Nov 1998.
+.R OE
+Richardson, M., Redelmeier, D. H., and Spencer, H.,
+"A method for doing opportunistic encryption with IKE",
+<draft-richardson-ipsec-opportunistic-06.txt>,
+21 Feb 2002 (work in progress).
+.R PKCS1v1
+Kaliski, B.,
+"PKCS #1: RSA Encryption, Version 1.5",
+RFC 2313, March 1998.
+.R PKCS1v2
+Kaliski, B., and Staddon, J.,
+"PKCS #1: RSA Cryptography Specifications, Version 2.0",
+RFC 2437, Oct 1998.
+.R PFKEY
+McDonald, D., Metz, C., and Phan, B.,
+"PF_KEY Key Management API, Version 2",
+RFC 2367, July 1998.
+.R REKEY
+Tim Jenkins, "IPsec Re-keying Issues",
+<draft-jenkins-ipsec-rekeying-06.txt>,
+2 May 2000 (draft expired, work no longer in progress).
+.R REPLAY
+Krywaniuk, A.,
+"Using Isakmp Message Ids for Replay Protection",
+<draft-krywaniuk-ipsec-antireplay-00.txt>,
+9 July 2001
+(work in progress).
+.R RSA
+Rivest, R.L., Shamir, A., and Adleman, L.,
+"A Method for Obtaining Digital Signatures and Public-Key
+Cryptosystems",
+Communications of the ACM v21n2, Feb 1978, p. 120.
+.R SCHNEIER
+Bruce Schneier, "Applied Cryptography", 2nd ed.,
+Wiley 1996, ISBN 0-471-11709-9.
+.R SECFAIL
+Karn, P., and Simpson, W.,
+"ICMP Security Failures Messages",
+RFC 2521,
+March 1999.
+.H
+Authors' Addresses
+.P
+.nf
+.ne 8
+Henry Spencer
+SP Systems
+Box 280 Stn. A
+Toronto, Ont. M5W1B2
+Canada
+
+henry@spsystems.net
+416-690-6561
+.ne 8
+.sp 2
+D. Hugh Redelmeier
+Mimosa Systems Inc.
+29 Donino Ave.
+Toronto, Ont. M4N2W6
+Canada
+
+hugh@mimosa.com
+416-482-8253
+.bp
+.H
+Full Copyright Statement
+.P
+Copyright (C) The Internet Society \*c. All Rights
+Reserved.
+
+This document and translations of it may be copied and
+furnished to others, and derivative works that comment on or
+otherwise explain it or assist in its implmentation may be
+prepared, copied, published and distributed, in whole or in
+part, without restriction of any kind, provided that the above
+copyright notice and this paragraph are included on all such
+copies and derivative works.  However, this document itself may
+not be modified in any way, such as by removing the copyright
+notice or references to the Internet Society or other Internet
+organizations, except as needed for the  purpose of developing
+Internet standards in which case the procedures for copyrights
+defined in the Internet Standards process must be followed, or
+as required to translate it into languages other than English.
+
+The limited permissions granted above are perpetual and will
+not be revoked by the Internet Society or its successors or
+assigns.
+
+This document and the information contained herein is provided
+on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET
+ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE
+OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY
+IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A
+PARTICULAR PURPOSE.
diff --git a/doc/draft-spencer-ipsec-ike-implementation.txt b/doc/draft-spencer-ipsec-ike-implementation.txt
new file mode 100644
index 000000000..145c00ba8
--- /dev/null
+++ b/doc/draft-spencer-ipsec-ike-implementation.txt
@@ -0,0 +1,1232 @@
+
+
+
+Network Working Group                                      Henry Spencer
+Internet Draft                                                SP Systems
+Expires: 26 Aug 2002                                  D. Hugh Redelmeier
+                                                          Mimosa Systems
+                                                             26 Feb 2002
+
+                       IKE Implementation Issues
+            <draft-spencer-ipsec-ike-implementation-02.txt>
+
+Status of this Memo
+
+   This document is an Internet-Draft and is in full conformance with
+   all provisions of Section 10 of RFC2026.
+
+   (If approved as an Informational RFC...)  This memo provides
+   information for the Internet community.  This memo does not specify
+   an Internet standard of any kind.
+
+   Distribution of this memo is unlimited.
+
+   Internet-Drafts are working documents of the Internet Engineering
+   Task Force (IETF), its areas, and its working groups.  Note that
+   other groups may also distribute working documents as Internet-
+   Drafts.
+
+   Internet-Drafts are draft documents valid for a maximum of six months
+   and may be updated, replaced, or obsoleted by other documents at any
+   time.  It is inappropriate to use Internet-Drafts as reference
+   material or to cite them other than as "work in progress."
+
+   The list of current Internet-Drafts can be accessed at
+   http://www.ietf.org/ietf/1id-abstracts.txt.
+
+   The list of Internet-Draft Shadow Directories can be accessed at
+   http://www.ietf.org/shadow.html.
+
+   This Internet-Draft will expire on 26 Aug 2002.
+
+Copyright Notice
+
+   Copyright (C) The Internet Society 2002.  All Rights Reserved.
+
+
+
+
+
+
+
+
+
+
+Spencer & Redelmeier                                            [Page 1]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+Table of Contents
+
+   1. Introduction ................................................... 3
+   2. Lower-level Background and Notes ............................... 4
+   2.1. Packet Handling .............................................. 4
+   2.2. Ciphers ...................................................... 5
+   2.3. Interfaces ................................................... 5
+   3. IKE Infrastructural Issues ..................................... 5
+   3.1. Continuous Channel ........................................... 5
+   3.2. Retransmission ............................................... 5
+   3.3. Replay Prevention ............................................ 6
+   4. Basic Keying and Rekeying ...................................... 7
+   4.1. When to Create SAs ........................................... 7
+   4.2. When to Rekey ................................................ 8
+   4.3. Choosing an SA ............................................... 9
+   4.4. Why to Rekey ................................................. 9
+   4.5. Rekeying ISAKMP SAs ......................................... 10
+   4.6. Bulk Negotiation ............................................ 10
+   5. Deletions, Teardowns, Crashes ................................. 11
+   5.1. Deletions ................................................... 11
+   5.2. Teardowns and Shutdowns ..................................... 12
+   5.3. Crashes ..................................................... 13
+   5.4. Network Partitions .......................................... 13
+   5.5. Unknown SAs ................................................. 14
+   6. Misc. IKE Issues .............................................. 16
+   6.1. Groups 1 and 5 .............................................. 16
+   6.2. To PFS Or Not To PFS ........................................ 16
+   6.3. Debugging Tools, Lack Thereof ............................... 16
+   6.4. Terminology, Vagueness Thereof .............................. 17
+   6.5. A Question of Identity ...................................... 17
+   6.6. Opportunistic Encryption .................................... 17
+   6.7. Authentication and RSA Keys ................................. 17
+   6.8. Misc. Snags ................................................. 18
+   7. Security Considerations ....................................... 19
+   8. References .................................................... 19
+   Authors' Addresses ............................................... 20
+   Full Copyright Statement ......................................... 21
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Spencer & Redelmeier                                            [Page 2]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+Abstract
+
+   The current IPsec specifications for key exchange and connection
+   management, RFCs 2408 [ISAKMP] and 2409 [IKE], leave many aspects of
+   connection management unspecified, most prominently rekeying
+   practices.  Pending clarifications in future revisions of the
+   specifications, this document sets down some successful experiences,
+   to minimize the extent to which new implementors have to rely on
+   unwritten folklore.
+
+   The Linux FreeS/WAN implementation of IPsec interoperates with almost
+   every other IPsec implementation.  This document describes how the
+   FreeS/WAN project has resolved some of the gaps in the IPsec
+   specifications (and plans to resolve some others), and what
+   difficulties have been encountered, in hopes that this generally-
+   successful experience might be informative to new implementors.
+
+   This is offered as an Informational RFC.
+
+   This -02 revision mainly: discusses ISAKMP SA expiry during IPsec-SA
+   rekeying (4.5), revises the discussion of bidirectional Deletes
+   (5.1), suggests remembering the parameters of successful negotiations
+   for later use (4.2, 5.3), notes an unsuccessful negotiation from the
+   other end as a hint of a possibly broken connection (5.5), and adds
+   sections on network partitions (5.4), authentication methods and the
+   subtleties of RSA public keys (6.7), and miscellaneous
+   interoperability concerns (6.8).
+
+1. Introduction
+
+   The current IPsec specifications for key exchange and connection
+   management, RFCs 2408 [ISAKMP] and 2409 [IKE], leave many aspects of
+   connection management unspecified, most prominently rekeying
+   practices.  This is a cryptic puzzle which each group of implementors
+   has to struggle with, and differences in how the ambiguities and gaps
+   are resolved are potentially a fruitful source of interoperability
+   problems.  We can hope that future revisions of the specifications
+   will clear this up.  Meanwhile, it seems useful to set down some
+   successful experiences, to minimize the extent to which new
+   implementors have to rely on unwritten folklore.
+
+   The Linux FreeS/WAN implementation of IPsec interoperates with almost
+   every other IPsec implementation, and because of its free nature, it
+   also sees some use as a reference implementation by other
+   implementors.  The high degree of interoperability is noteworthy
+   given its organizers' strong minimalist bias, which has caused them
+   to implement only a small subset of the full glory of IPsec.  This
+   document describes how the FreeS/WAN project has resolved some of the
+
+
+
+Spencer & Redelmeier                                            [Page 3]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+   gaps in the IPsec specifications (and plans to resolve some others),
+   and what difficulties have been encountered, in hopes that this
+   generally-successful experience might be informative to new
+   implementors.
+
+   One small caution about applicability: this experience may not be
+   relevant to severely resource-constrained implementations.
+   FreeS/WAN's target environment is previous-generation PCs, now
+   available at trivial cost (often, within an organization, at no
+   cost), which have quite impressive CPU power and memory by the
+   standards of only a few years ago.  Some of the approaches discussed
+   here may be inapplicable to implementations with severe external
+   constraints which prevent them from taking advantage of modern
+   hardware technology.
+
+2. Lower-level Background and Notes
+
+2.1. Packet Handling
+
+   FreeS/WAN implements ESP [ESP] and AH [AH] straightforwardly,
+   although AH sees little use among our users.  Our ESP/AH
+   implementation cannot currently handle packets with IP options;
+   somewhat surprisingly, this has caused little difficulty.  We insist
+   on encryption and do not support authentication-only connections, and
+   this has not caused significant difficulty either.
+
+   MTU and fragmentation issues, by contrast, have been a constant
+   headache.  We will not describe the details of our current approach
+   to them, because it still needs work.  One difficulty we have
+   encountered is that many combinations of packet source and packet
+   destination apparently cannot cope with an "interior minimum" in the
+   path MTU, e.g. where an IPsec tunnel intervenes and its headers
+   reduce the MTU for an intermediate link.  This is particularly
+   prevalent when using common PC software to connect to large well-
+   known web sites; we think it is largely due to misconfigured
+   firewalls which do not pass ICMP Fragmentation Required messages.
+   The only solution we have yet found is to lie about the MTU of the
+   tunnel, accepting the (undesirable) fragmentation of the ESP packets
+   for the sake of preserving connectivity.
+
+   We currently zero out the TOS field of ESP packets, rather than
+   copying it from the inner header, on the grounds that it lends itself
+   too well to traffic analysis and covert channels.  We provide an
+   option to restore RFC 2401 [IPSEC] copying behavior, but this appears
+   to see little use.
+
+
+
+
+
+
+Spencer & Redelmeier                                            [Page 4]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+2.2. Ciphers
+
+   We initially implemented both DES [DES] and 3DES [CIPHERS] for both
+   IKE and ESP, but after the Deep Crack effort [CRACK] demonstrated its
+   inherent insecurity, we dropped support for DES.  Somewhat
+   surprisingly, our insistence on 3DES has caused almost no
+   interoperability problems, despite DES being officially mandatory.  A
+   very few other systems either do not support 3DES or support it only
+   as an optional upgrade, which inconveniences a few would-be users.
+   There have also been one or two cases of systems which don't quite
+   seem to know the difference!
+
+   See also section 6.1 for a consequence of our insistence on 3DES.
+
+2.3. Interfaces
+
+   We currently employ PF_KEY version 2 [PFKEY], plus various non-
+   standard extensions, as our interface between keying and ESP.  This
+   has not proven entirely satisfactory.  Our feeling now is that keying
+   issues and policy issues do not really lend themselves to the clean
+   separation that PF_KEY envisions.
+
+3. IKE Infrastructural Issues
+
+   A number of problems in IPsec connection management become easier if
+   some attention is first paid to providing an infrastructure to
+   support solving them.
+
+3.1. Continuous Channel
+
+   FreeS/WAN uses an approximation to the "continuous channel" model, in
+   which ISAKMP SAs are maintained between IKEs so long as any IPsec SAs
+   are open between the two systems.  The resource consumption of this
+   is minor: the only substantial overhead is occasional rekeying.
+   IPsec SA management becomes significantly simpler if there is always
+   a channel for transmission of control messages.  We suggest (although
+   we do not yet fully implement this) that inability to maintain (e.g.,
+   to rekey) this control path should be grounds for tearing down the
+   IPsec SAs as well.
+
+   As a corollary of this, there is one and only one ISAKMP SA
+   maintained between a pair of IKEs (although see sections 5.3 and 6.5
+   for minor complications).
+
+3.2. Retransmission
+
+   The unreliable nature of UDP transmission is a nuisance.  IKE
+   implementations should always be prepared to retransmit the most
+
+
+
+Spencer & Redelmeier                                            [Page 5]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+   recent message they sent on an ISAKMP SA, since there is some
+   possibility that the other end did not get it.  This means, in
+   particular, that the system sending the supposedly-last message of an
+   exchange cannot relax and assume that the exchange is complete, at
+   least not until a significant timeout has elapsed.
+
+   Systems must also retain information about the message most recently
+   received in an exchange, so that a duplicate of it can be detected
+   (and possibly interpreted as a NACK for the response).
+
+   The retransmission rules FreeS/WAN follows are: (1) if a reply is
+   expected, retransmit only if it does not appear before a timeout; and
+   (2) if a reply is not expected (last message of the exchange),
+   retransmit only on receiving a retransmission of the previous
+   message.  Notably, in case (1) we do NOT retransmit on receiving a
+   retransmission, which avoids possible congestion problems arising
+   from packet duplication, at the price of slowing response to packet
+   loss.  The timeout for case (1) is 10 seconds for the first retry, 20
+   seconds for the second, and 40 seconds for all subsequent retries
+   (normally only one, except when configuration settings call for
+   persistence and the message is the first message of Main Mode with a
+   new peer).  These retransmission rules have been entirely successful.
+
+   (Michael Thomas of Cisco has pointed out that the retry timeouts
+   should include some random jitter, to de-synchronize hosts which are
+   initially synchronized by, e.g., a power outage.  We already jitter
+   our rekeying times, as noted in section 4.2, but that does not help
+   with initial startup.  We're implementing jittered retries, but
+   cannot yet report on experience with this.)
+
+   There is a deeper problem, of course, when an entire "exchange"
+   consists of a single message, e.g. the ISAKMP Informational Exchange.
+   Then there is no way to decide whether or when a retransmission is
+   warranted at all.  This seems like poor design, to put it mildly (and
+   there is now talk of fixing it).  We have no experience in dealing
+   with this problem at this time, although it is part of the reason why
+   we have delayed implementing Notification messages.
+
+3.3. Replay Prevention
+
+   The unsequenced nature of UDP transmission is also troublesome,
+   because it means that higher levels must consider the possibility of
+   replay attacks.  FreeS/WAN takes the position that systematically
+   eliminating this possibility at a low level is strongly preferable to
+   forcing careful consideration of possible impacts at every step of an
+   exchange.  RFC 2408 [ISAKMP] section 3.1 states that the Message ID
+   of an ISAKMP message must be "unique".  FreeS/WAN interprets this
+   literally, as forbidding duplication of Message IDs within the set of
+
+
+
+Spencer & Redelmeier                                            [Page 6]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+   all messages sent via a single ISAKMP SA.
+
+   This requires remembering all Message IDs until the ISAKMP SA is
+   superseded by rekeying, but that is not costly (four bytes per sent
+   or received message), and it ELIMINATES replay attacks from
+   consideration; we believe this investment of resources is well
+   worthwhile.  If the resource consumption becomes excessive--in our
+   experience it has not--the ISAKMP SA can be rekeyed early to collect
+   the garbage.
+
+   There is theoretically an interoperability problem when talking to
+   implementations which interpret "unique" more loosely and may re-use
+   Message IDs, but it has not been encountered in practice.  This
+   approach appears to be completely interoperable.
+
+   The proposal by Andrew Krywaniuk [REPLAY], which advocates turning
+   the Message ID into an anti-replay counter, would achieve the same
+   goal without the minor per-message memory overhead.  This may be
+   preferable, although it means an actual protocol change and more
+   study is needed.
+
+4. Basic Keying and Rekeying
+
+4.1. When to Create SAs
+
+   As Tim Jenkins [REKEY] pointed out, there is a potential race
+   condition in Quick Mode: a fast lightly-loaded Initiator might start
+   using IPsec SAs very shortly after sending QM3 (the third and last
+   message of Quick Mode), while a slow heavily-loaded Responder might
+   not be ready to receive them until after spending a significant
+   amount of time creating its inbound SAs.  The problem is even worse
+   if QM3 gets delayed or lost.
+
+   FreeS/WAN's approach to this is what Jenkins called "Responder Pre-
+   Setup": the Responder creates its inbound IPsec SAs before it sends
+   QM2, so they are always ready and waiting when the Initiator sends
+   QM3 and begins sending traffic.  This approach is simple and
+   reliable, and in our experience it interoperates with everybody.
+   (There is potentially still a problem if FreeS/WAN is the Initiator
+   and the Responder does not use Responder Pre-Setup, but no such
+   problems have been seen.)  The only real weakness of Responder Pre-
+   Setup is the possibility of replay attacks, which we have eliminated
+   by other means (see section 3.3).
+
+   With this approach, the Commit Bit is useless, and we ignore it.  In
+   fact, until quite recently we discarded any IKE message containing
+   it, and this caused surprisingly few interoperability problems;
+   apparently it is not widely used.  We have recently been persuaded
+
+
+
+Spencer & Redelmeier                                            [Page 7]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+   that simply ignoring it is preferable; preliminary experience with
+   this indicates that the result is successful interoperation with
+   implementations which set it.
+
+4.2. When to Rekey
+
+   To preserve connectivity for user traffic, rekeying of a connection
+   (that is, creation of new IPsec SAs to supersede the current ones)
+   must begin before its current IPsec SAs expire.  Preferably one end
+   should predictably start rekeying negotiations first, to avoid the
+   extra overhead of two simultaneous negotiations, although either end
+   should be prepared to rekey if the other does not.  There is also a
+   problem with "convoys" of keying negotiations: for example, a "hub"
+   gateway with many IPsec connections can be inundated with rekeying
+   negotiations exactly one connection-expiry time after it reboots, and
+   the massive overload this induces tends to make this situation self-
+   perpetuating, so it recurs regularly.  (Convoys can also evolve
+   gradually from initially-unsynchronized negotiations.)
+
+   FreeS/WAN has the concept of a "rekeying margin", measured in
+   seconds.  If FreeS/WAN was the Initiator for the previous rekeying
+   (or the startup, if none) of the connection, it nominally starts
+   rekeying negotiations at expiry time minus one rekeying margin.  Some
+   random jitter is added to break up convoys: rather than starting
+   rekeying exactly at minus one margin, it starts at a random time
+   between minus one margin and minus two margins.  (The randomness here
+   need not be cryptographic in quality, so long as it varies over time
+   and between hosts.  We use an ordinary PRNG seeded with a few bytes
+   from a cryptographic randomness source.  The seeding mostly just
+   ensures that the PRNG sequence is different for different hosts, even
+   if they start up simultaneously.)
+
+   If FreeS/WAN was the Responder for the previous rekeying/startup, and
+   nothing has been heard from the previous Initiator at expiry time
+   minus one-half the rekeying margin, FreeS/WAN will initiate rekeying
+   negotiations.  No jitter is applied; we now believe that it should be
+   jittered, say between minus one-half margin and minus one-quarter
+   margin.
+
+   Having the Initiator lead the way is an obvious way of deciding who
+   should speak first, since there is already an Initiator/Responder
+   asymmetry in the connection.  Moreover, our experience has been that
+   Initiator lead gives a significantly higher probability of successful
+   negotiation!  The negotiation process itself is asymmetric, because
+   the Initiator must make a few specific proposals which the Responder
+   can only accept or reject, so the Initiator must try to guess where
+   its "acceptable" region (in parameter space) might overlap with the
+   Responder's.  We have seen situations where negotiations would
+
+
+
+Spencer & Redelmeier                                            [Page 8]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+   succeed or fail depending on which end initiated them, because one
+   end was making better guesses.  Given an existing connection, we KNOW
+   that the previous Initiator WAS able to initiate a successful
+   negotiation, so it should (if at all possible) take the lead again.
+   Also, the Responder should remember the Initiator's successful
+   proposal, and start from that rather than from his own default
+   proposals if he must take the lead; we don't currently implement this
+   completely but plan to.
+
+   FreeS/WAN defaults the rekeying margin to 9 minutes, although this
+   can be changed by configuration.  There is also a configuration
+   option to alter the permissible range of jitter.  The defaults were
+   chosen somewhat arbitrarily, but they work extremely well and the
+   configuration options are rarely used.
+
+4.3. Choosing an SA
+
+   Once rekeying has occurred, both old and new IPsec SAs for the
+   connection exist, at least momentarily.  FreeS/WAN accepts incoming
+   traffic on either old or new inbound SAs, but sends outgoing traffic
+   only on the new outbound ones.  This approach appears to be
+   significantly more robust than using the old ones until they expire,
+   notably in cases where renegotiation has occurred because something
+   has gone wrong on the other end.  It avoids having to pay meticulous
+   attention to the state of the other end, state which is difficult to
+   learn reliably given the limitations of IKE.
+
+   This approach has interoperated successfully with ALMOST all other
+   implementations.  The only (well-characterized) problem cases have
+   been implementations which rely on receiving a Delete message for the
+   old SAs to tell them to switch over to the new ones.  Since delivery
+   of Delete is unreliable, and support for Delete is optional, this
+   reliance seems like a serious mistake.  This is all the more true
+   because Delete announces that the deletion has already occurred
+   [ISAKMP, section 3.15], not that it is about to occur, so packets
+   already in transit in the other direction could be lost.  Delete
+   should be used for resource cleanup, not for switchover control.
+   (These matters are discussed further in section 5.)
+
+4.4. Why to Rekey
+
+   FreeS/WAN currently implements only time-based expiry (life in
+   seconds), although we are working toward supporting volume-based
+   expiry (life in kilobytes) as well.  The lack of volume-based expiry
+   has not been an interoperability problem so far.
+
+   Volume-based expiry does add some minor complications.  In
+   particular, it makes explicit Delete of now-disused SAs more
+
+
+
+Spencer & Redelmeier                                            [Page 9]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+   important, because once an SA stops being used, it might not expire
+   on its own.  We believe this lacks robustness and is generally
+   unwise, especially given the lack of a reliable Delete, and expect to
+   use volume-based expiry only as a supplement to time-based expiry.
+   However, Delete support (see section 5) does seem advisable for use
+   with volume-based expiry.
+
+   We do not believe that volume-based expiry alters the desirability of
+   switching immediately to the new SAs after rekeying.  Rekeying
+   margins are normally a small fraction of the total life of an SA, so
+   we feel there is no great need to "use it all up".
+
+4.5. Rekeying ISAKMP SAs
+
+   The above discussion has focused on rekeying for IPsec SAs, but
+   FreeS/WAN applies the same approaches to rekeying for ISAKMP SAs,
+   with similar success.
+
+   One issue which we have noticed, but not explicitly dealt with, is
+   that difficulties may ensue if an IPsec-SA rekeying negotiation is in
+   progress at the time when the relevant ISAKMP SA gets rekeyed.  The
+   IKE specification [IKE] hints, but does not actually say, that a
+   Quick Mode negotiation should remain on a single ISAKMP SA
+   throughout.
+
+   A reasonable rekeying margin will generally prevent the old ISAKMP SA
+   from actually expiring during a negotiation.  Some attention may be
+   needed to prevent in-progress negotiations from being switched to the
+   new ISAKMP SA.  Any attempt at pre-expiry deletion of the ISAKMP SA
+   must be postponed until after such dangling negotiations are
+   completed, and there should be enough delay between ISAKMP-SA
+   rekeying and a deletion attempt to (more or less) ensure that there
+   are no negotiation-starting packets still in transit from before the
+   rekeying.
+
+   At present, FreeS/WAN does none of this, and we don't KNOW of any
+   resulting trouble.  With normal lifetimes, the problem should be
+   uncommon, and we speculate that an occasional disrupted negotiation
+   simply gets retried.
+
+4.6. Bulk Negotiation
+
+   Quick Mode nominally provides for negotiating possibly-large numbers
+   of similar but unrelated IPsec SAs simultaneously [IKE, section 9].
+   Nobody appears to do this.  FreeS/WAN does not support it, and its
+   absence has caused no problems.
+
+
+
+
+
+Spencer & Redelmeier                                           [Page 10]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+5. Deletions, Teardowns, Crashes
+
+   FreeS/WAN currently ignores all Notifications and Deletes, and never
+   generates them.  This has caused little difficulty in
+   interoperability, which shouldn't be surprising (since Notification
+   and Delete support is officially entirely optional) but does seem to
+   surprise some people.  Nevertheless, we do plan some changes to this
+   approach based on past experience.
+
+5.1. Deletions
+
+   As hinted at above, we plan to implement Delete support, done as
+   follows.  Shortly after rekeying of IPsec SAs, the Responder issues a
+   Delete for its old inbound SAs (but does not actually delete them
+   yet).  The Responder initiates this because the Initiator started
+   using the new SAs on sending QM3, while the Responder started using
+   them only on (or somewhat after) receiving QM3, so there is less
+   chance of old-SA packets still being in transit from the Initiator.
+   The Initiator issues an unsolicited Delete only if it does not hear
+   one from the Responder after a longer delay.
+
+   Either party, on receiving a Delete for one or more of the old
+   outbound SAs of a connection, deletes ALL the connection's SAs, and
+   acknowledges with a Delete for the old inbound SAs.  A Delete for
+   nonexistent SAs (e.g., SAs which have already been expired or
+   deleted) is ignored.  There is no retransmission of unacknowledged
+   Deletes.
+
+   In the normal case, with prompt reliable transmission (except
+   possibly for loss of the Responder's initial Delete) and conforming
+   implementations on both ends, this results in three Deletes being
+   transmitted, resembling the classic three-way handshake.  Loss of a
+   Delete after the first, or multiple losses, will cause the SAs not to
+   be deleted on at least one end.  It appears difficult to do much
+   better without at least a distinction between request and
+   acknowledgement.
+
+   RFC 2409 section 9 "strongly suggests" that there be no response to
+   informational messages such as Deletes, but the only rationale
+   offered is prevention of infinite loops endlessly exchanging "I don't
+   understand you" informationals.  Since Deletes cannot lead to such a
+   loop (and in any case, the nonexistent-SA rule prevents more than one
+   acknowledgement for the same connection), we believe this
+   recommendation is inapplicable here.
+
+   As noted in section 4.3, these Deletes are intended for resource
+   cleanup, not to control switching between SAs.  But we expect that
+   they will improve interoperability with some broken implementations.
+
+
+
+Spencer & Redelmeier                                           [Page 11]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+   We believe strongly that connections need to be considered as a
+   whole, rather than treating each SA as an independent entity.  We
+   will issue Deletes only for the full set of inbound SAs of a
+   connection, and will treat a Delete for any outbound SA as equivalent
+   to deletion of all the outbound SAs for the associated connection.
+
+   The above is phrased in terms of IPsec SAs, but essentially the same
+   approach can be applied to ISAKMP SAs (the Deletes for the old ISAKMP
+   SA should be sent via the new one).
+
+5.2. Teardowns and Shutdowns
+
+   When a connection is not intended to be up permanently, there is a
+   need to coordinate teardown, so that both ends are aware that the
+   connection is down.  This is both for recovery of resources, and to
+   avoid routing packets through dangling SAs which can no longer
+   deliver them.
+
+   Connection teardown will use the same bidirectional exchange of
+   Deletes as discussed in section 5.1: a Delete received for current
+   IPsec SAs (not yet obsoleted by rekeying) indicates that the other
+   host wishes to tear down the associated connection.
+
+   A Delete received for a current ISAKMP SA indicates that the other
+   host wishes to tear down not only the ISAKMP SA but also all IPsec
+   SAs currently under the supervision of that ISAKMP SA.  The 5.1
+   bidirectional exchange might seem impossible in this case, since
+   reception of an ISAKMP-SA Delete indicates that the other end will
+   ignore further traffic on that ISAKMP SA.  We suggest using the same
+   tactic discussed in 5.1 for IPsec SAs: the first Delete is sent
+   without actually doing the deletion, and the response to receiving a
+   Delete is to do the deletion and reply with another Delete.  If there
+   is no response to the first Delete, retry a small number of times and
+   then give up and do the deletion; apart from being robust against
+   packet loss, this also maximizes the probability that an
+   implementation which does not do the bidirectional Delete will
+   receive at least one of the Deletes.
+
+   When a host with current connections knows that it is about to shut
+   down, it will issue Deletes for all SAs involved (both IPsec and
+   ISAKMP), advising its peers (as per the meaning of Delete [ISAKMP,
+   section 3.15]) that the SAs have become useless.  It will ignore
+   attempts at rekeying or connection startup thereafter, until it shuts
+   down.
+
+   It would be better to have a Final-Contact notification, analogous to
+   Initial-Contact but indicating that no new negotiations should be
+   attempted until further notice.  Initial-Contact actually could be
+
+
+
+Spencer & Redelmeier                                           [Page 12]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+   used for shutdown notification (!), but in networks where connections
+   are intended to exist permanently, it seems likely to provoke
+   unwanted attempts to renegotiate the lost connections.
+
+5.3. Crashes
+
+   Systems sometimes crash.  Coping with the resulting loss of
+   information is easily the most difficult problem we have found in
+   implementing robust IPsec systems.
+
+   When connections are intended to be permanent, it is simple to
+   specify renegotiation on reboot.  With our approach to SA selection
+   (see section 4.3), this handles such cases robustly and well.  We do
+   have to tell users that BOTH hosts should be set this way.  In cases
+   where crashes are synchronized (e.g. by power interruptions), this
+   may result in simultaneous negotiations at reboot.  We currently
+   allow both negotiations to proceed to completion, but our use-newest
+   selection method effectively ignores one connection or the other, and
+   when one of them rekeys, we notice that the new SAs replace those of
+   both old connections, and we then refrain from rekeying the other.
+   (This duplicate detection is desirable in any event, for robustness,
+   to ensure that the system converges on a reasonable state eventually
+   after it is perturbed by difficulties or bugs.)
+
+   When connections are not permanent, the situation is less happy.  One
+   particular situation in which we see problems is when a number of
+   "Road Warrior" hosts occasionally call in to a central server.  The
+   server is normally configured not to initiate such connections, since
+   it does not know when the Road Warrior is available (or what IP
+   address it is using).  Unfortunately, if the server crashes and
+   reboots, any Road Warriors then connected have a problem: they don't
+   know that the server has crashed, so they can't renegotiate, and the
+   server has forgotten both the connections and their (transient) IP
+   addresses, so it cannot renegotiate.
+
+   We believe that the simplest answer to this problem is what John
+   Denker has dubbed "address inertia": the server makes a best-effort
+   attempt to remember (in nonvolatile storage) which connections were
+   active and what the far-end addresses were (and what the successful
+   proposal's parameters were), so that it can attempt renegotiation on
+   reboot.  We have not implemented this yet, but intend to; Denker has
+   implemented it himself, although in a somewhat messy way, and reports
+   excellent results.
+
+5.4. Network Partitions
+
+   A network partition, making the two ends unable to reach each other,
+   has many of the same characteristics as having the other end crash...
+
+
+
+Spencer & Redelmeier                                           [Page 13]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+   until the network reconnects.  It is desirable that recovery from
+   this be automatic.
+
+   If the network reconnects before any rekeying attempts or other IKE
+   activities occurred, recovery is fully transparent, because the IKEs
+   have no idea that there was any problem.  (Complaints such as ICMP
+   Host Unreachable messages are unauthenticated and hence cannot be
+   given much weight.)  This fits the general mold of TCP/IP: if nobody
+   wanted to send any traffic, a network outage doesn't matter.
+
+   If IKE activity did occur, the IKE implementation will discover that
+   the other end doesn't seem to be responding.  The preferred response
+   to this depends on the nature of the connection.  If it was intended
+   to be ephemeral (e.g. opportunistic encryption [OE]), closing it down
+   after a few retries is reasonable.  If the other end is expected to
+   sometimes drop the connection without warning, it may not be
+   desirable to retry at all.  (We support both these forms of
+   configurability, and indeed we also have a configuration option to
+   suppress rekeying entirely on one end.)
+
+   If the connection was intended to be permanent, however, then
+   persistent attempts to re-establish it are appropriate.  Some degree
+   of backoff is appropriate here, so that retries get less frequent as
+   the outage gets prolonged.  Backoff should be limited, so that re-
+   established connectivity is not followed by a long delay before a
+   retry.  Finally, after many retries (say 24 hours' worth), it may be
+   preferable to just declare the connection down and rely on manual
+   intervention to re-establish it, should this be desirable.  We do not
+   yet fully support all this.
+
+5.5. Unknown SAs
+
+   A more complete solution to crashes would be for an IPsec host to
+   note the arrival of ESP packets on an unknown IPsec SA, and report it
+   somehow to the other host, which can then decide to renegotiate.
+   This arguably might be preferable in any case--if the non-rebooted
+   host has no traffic to send, it does not care whether the connection
+   is intact--but delays and packet loss will be reduced if the
+   connection is renegotiated BEFORE there is traffic for it.  So
+   unknown-SA detection is best reserved as a fallback method, with
+   address inertia used to deal with most such cases.
+
+   A difficulty with unknown-SA detection is, just HOW should the other
+   host be notified?  IKE provides no good way to do the notification:
+   Notification payloads (e.g., Initial-Contact) are unauthenticated
+   unless they are sent under protection of an ISAKMP SA.  A "Security
+   Failures - Bad SPI" ICMP message [SECFAIL] is an interesting
+   alternative, but has the disadvantage of likewise being
+
+
+
+Spencer & Redelmeier                                           [Page 14]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+   unauthenticated.  It's fundamentally unlikely that there is a simple
+   solution to this, given that almost any way of arranging or checking
+   authentication for such a notification is costly.
+
+   We think the best answer to this is a two-step approach.  An
+   unauthenticated Initial-Contact or Security Failures - Bad SPI cannot
+   be taken as a reliable report of a problem, but can be taken as a
+   hint that a problem MIGHT exist.  Then there needs to be some
+   reliable way of checking such hints, subject to rate limiting since
+   the checks are likely to be costly (and checking the same connection
+   repeatedly at short intervals is unlikely to be worthwhile anyway).
+   So the rebooted host sends the notification, and the non-rebooted
+   host--which still thinks it has a connection--checks whether the
+   connection still works, and renegotiates if not.
+
+   Also, if an IPsec host which believes it has a connection to another
+   host sees an unsuccessful attempt by that host to negotiate a new
+   one, that is also a hint of possible problems, justifying a check and
+   possible renegotiation.  ("Unsuccessful" here means a negotiation
+   failure due to lack of a satisfactory proposal.  A failure due to
+   authentication failure suggests a denial-of-service attack by a third
+   party, rather than a genuine problem on the legitimate other end.)
+   As noted in section 4.2, it is possible for negotiations to succeed
+   or fail based on which end initiates them, and some robustness
+   against that is desirable.
+
+   We have not yet decided what form the notification should take.  IKE
+   Initial-Contact is an obvious possibility, but has some
+   disadvantages.  It does not specify which connection has had
+   difficulties.  Also, the specification [IKE section 4.6.3.3] refers
+   to "remote system" and "sending system" without clearly specifying
+   just what "system" means; in the case of a multi-homed host using
+   multiple forms of identification, the question is not trivial.
+   Initial-Contact does have the fairly-decisive advantage that it is
+   likely to convey the right general meaning even to an implementation
+   which does not do things exactly the way ours does.
+
+   A more fundamental difficulty is what form the reliable check takes.
+   What is wanted is an "IKE ping", verifying that the ISAKMP SA is
+   still intact (it being unlikely that IPsec SAs have been lost while
+   the ISAKMP SA has not).  The lack of such a facility is a serious
+   failing of IKE.  An acknowledged Notification of some sort would be
+   ideal, but there is none at present.  Some existing implementations
+   are known to use the private Notification values 30000 as ping and
+   30002 as ping reply, and that seems the most attractive choice at
+   present.  If it is not recognized, there will probably be no reply,
+   and the result will be an unnecessary renegotiation, so this needs
+   strict rate limiting.  (Also, when a new connection is set up, it's
+
+
+
+Spencer & Redelmeier                                           [Page 15]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+   probably worth determining by experiment whether the other end
+   supports IKE ping, and remembering that.)
+
+   While we think this facility is desirable, and is about the best that
+   can be done with the poor tools available, we have not gotten very
+   far in implementation and cannot comment intelligently about how well
+   it works or interoperates.
+
+6. Misc. IKE Issues
+
+6.1. Groups 1 and 5
+
+   We have dropped support for the first Oakley Group (group 1), despite
+   it being officially mandatory, on the grounds that it is grossly too
+   weak to provide enough randomness for 3DES.  There have been some
+   interoperability problems, mostly quite minor: ALMOST everyone
+   supports group 2 as well, although sometimes it has to be explicitly
+   configured.
+
+   We also support the quasi-standard group 5 [GROUPS].  This has not
+   been seriously exercised yet, because historically we offered group 2
+   first and almost everyone accepted it.  We have recently changed to
+   offering group 5 first, and no difficulties have been reported.
+
+6.2. To PFS Or Not To PFS
+
+   A persistent small interoperability problem is that the presence or
+   absence of PFS (for keys [IKE, section 5.5]) is neither negotiated
+   nor announced.  We have it enabled by default, and successful
+   interoperation often requires having the other end turn it on in
+   their implementation, or having the FreeS/WAN end disable it.  Almost
+   everyone supports it, but it's usually not the default, and
+   interoperability is often impossible unless the two ends somehow
+   reach prior agreement on it.
+
+   We do not explicitly support the other flavor of PFS, for identities
+   [IKE, section 8], and this has caused no interoperability problems.
+
+6.3. Debugging Tools, Lack Thereof
+
+   We find IKE lacking in basic debugging tools.  Section 5.4, above,
+   notes that an IKE ping would be useful for connectivity verification.
+   It would also be extremely helpful for determining that UDP/500
+   packets get back and forth successfully between the two ends, which
+   is often an important first step in debugging.
+
+   It's also quite common to have IKE negotiate a connection
+   successfully, but to have some firewall along the way blocking ESP.
+
+
+
+Spencer & Redelmeier                                           [Page 16]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+   Users find this mysterious and difficult to diagnose.  We have no
+   immediate suggestions on what could be done about it.
+
+6.4. Terminology, Vagueness Thereof
+
+   The terminology of IPsec needs work.  We feel that both the
+   specifications and user-oriented documentation would be greatly
+   clarified by concise, intelligible names for certain concepts.
+
+   We semi-consistently use "group" for the set of IPsec SAs which are
+   established in one direction by a single Quick Mode negotiation and
+   are used together to process a packet (e.g., an ESP SA plus an AH
+   SA), "connection" for the logical packet path provided by a
+   succession of pairs of groups (each rekeying providing a new pair,
+   one group in each direction), and "keying channel" for the
+   corresponding supervisory path provided by a sequence of ISAKMP SAs.
+
+   We think it's a botch that "PFS" is used to refer to two very
+   different things, but we have no specific new terms to suggest, since
+   we only implement one kind of PFS and thus can just ignore the other.
+
+6.5. A Question of Identity
+
+   One specification problem deserves note: exactly when can an existing
+   phase 1 negotiation be re-used for a new phase 2 negotiation, as IKE
+   [IKE, section 4] specifies?  Presumably, when it connects the same
+   two "parties"... but exactly what is a "party"?
+
+   As noted in section 5.4, in cases involving multi-homing and multiple
+   identities, it's not clear exactly what criteria are used for
+   deciding whether the intended far end for a new negotiation is the
+   same one as for a previous negotiation.  Is it by Identification
+   Payload?  By IP address?  Or what?
+
+   We currently use a somewhat-vague notion of "identity", basically
+   what gets sent in Identification Payloads, for this, and this seems
+   to be successful, but we think this needs better specification.
+
+6.6. Opportunistic Encryption
+
+   Further IKE challenges appear in the context of Opportunistic
+   Encryption [OE], but operational experience with it is too limited as
+   yet for us to comment usefully right now.
+
+6.7. Authentication and RSA Keys
+
+   We provide two IKE authentication methods: shared secrets ("pre-
+   shared keys") and RSA digital signatures.  (A user-provided add-on
+
+
+
+Spencer & Redelmeier                                           [Page 17]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+   package generalizes the latter to limited support for certificates;
+   we have not worked extensively with it ourselves yet and cannot
+   comment on it yet.)
+
+   Shared secrets, despite their administrative difficulties, see
+   considerable use, and are also the method of last resort for
+   interoperability problems.
+
+   For digital signatures, we have taken the somewhat unorthodox
+   approach of using "bare" RSA public keys, either supplied in
+   configuration files or fetched from DNS, rather than getting involved
+   in the complexity of certificates.  We encode our RSA public keys
+   using the DNS KEY encoding [DNSRSA] (aka "RFC 2537", although that
+   RFC is now outdated), which has given us no difficulties and which we
+   highly recommend.  We have seen two difficulties in connection with
+   RSA keys, however.
+
+   First, while a number of IPsec implementations are able to take
+   "bare" RSA public keys, each one seems to have its own idea of what
+   format should be used for transporting them.  We've had little
+   success with interoperability here, mostly because of key-format
+   issues; the implementations generally WILL interoperate successfully
+   if you can somehow get an RSA key into them at all, but that's hard.
+   X.509 certificates seem to be the lowest (!)  common denominator for
+   key transfer.
+
+   Second, although the content of RSA public keys has been stable,
+   there has been a small but subtle change over time in the content of
+   RSA private keys.  The "internal modulus", used to compute the
+   private exponent "d" from the public exponent "e" (or vice-versa) was
+   originally [RSA] [PKCS1v1] [SCHNEIER] specified to be (p-1)*(q-1),
+   where p and q are the two primes.  However, more recent definitions
+   [PKCS1v2] call it "lambda(n)" and define it to be lcm(p-1, q-1); this
+   appears to be a minor optimization.  The result is that private keys
+   generated with the new definition often fail consistency checks in
+   implementations using the old definition.  Fortunately, it is seldom
+   necessary to move private keys around.  Our software now consistently
+   uses the new definition (and thus will accept keys generated with
+   either definition), but our key generator also has an option to
+   generate old-definition keys, for the benefit of users who upgrade
+   their networks incrementally.
+
+6.8. Misc. Snags
+
+   Nonce size is another characteristic that is neither negotiated nor
+   announced but that the two ends must somehow be able to agree on.
+   Our software accepts anything between 8 and 256, and defaults to 16.
+   These numbers were chosen rather arbitrarily, but we have seen no
+
+
+
+Spencer & Redelmeier                                           [Page 18]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+   interoperability failures here.
+
+   Nothing in the ISAKMP [ISAKMP] or IKE [IKE] specifications says
+   explicitly that a normal Message ID must be non-zero, but a zero
+   Message ID in fact causes failures.
+
+   Similarly, there is nothing in the specs which says that ISAKMP
+   cookies must be non-zero, but zero cookies will in fact cause
+   trouble.
+
+7. Security Considerations
+
+   Since this document discusses aspects of building robust and
+   interoperable IPsec implementations, security considerations permeate
+   it.
+
+8. References
+
+   [AH]       Kent, S., and Atkinson, R., "IP Authentication Header",
+              RFC 2402, Nov 1998.
+
+   [CIPHERS]  Pereira, R., and Adams, R., "The ESP CBC-Mode Cipher
+              Algorithms", RFC 2451, Nov 1998.
+
+   [CRACK]    Electronic Frontier Foundation, "Cracking DES: Secrets of
+              Encryption Research, Wiretap Politics and Chip Design",
+              O'Reilly 1998, ISBN 1-56592-520-3.
+
+   [DES]      Madson, C., and Doraswamy, N., "The ESP DES-CBC Cipher
+              Algorithm", RFC 2405, Nov 1998.
+
+   [DNSRSA]   D. Eastlake 3rd, "RSA/SHA-1 SIGs and RSA KEYs in the
+              Domain Name System (DNS)", RFC 3110, May 2001.
+
+   [ESP]      Kent, S., and Atkinson, R., "IP Encapsulating Security
+              Payload (ESP)", RFC 2406, Nov 1998.
+
+   [GROUPS]   Kivinen, T., and Kojo, M., "More MODP Diffie-Hellman
+              groups for IKE", <draft-ietf-ipsec-ike-modp-
+              groups-04.txt>, 13 Dec 2001 (work in progress).
+
+   [IKE]      Harkins, D., and Carrel, D., "The Internet Key Exchange
+              (IKE)", RFC 2409, Nov 1998.
+
+   [IPSEC]    Kent, S., and Atkinson, R., "Security Architecture for the
+              Internet Protocol", RFC 2401, Nov 1998.
+
+
+
+
+
+Spencer & Redelmeier                                           [Page 19]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+   [ISAKMP]   Maughan, D., Schertler, M., Schneider, M., and Turner, J.,
+              "Internet Security Association and Key Management Protocol
+              (ISAKMP)", RFC 2408, Nov 1998.
+
+   [OE]       Richardson, M., Redelmeier, D. H., and Spencer, H., "A
+              method for doing opportunistic encryption with IKE",
+              <draft-richardson-ipsec-opportunistic-06.txt>, 21 Feb 2002
+              (work in progress).
+
+   [PKCS1v1]  Kaliski, B., "PKCS #1: RSA Encryption, Version 1.5", RFC
+              2313, March 1998.
+
+   [PKCS1v2]  Kaliski, B., and Staddon, J., "PKCS #1: RSA Cryptography
+              Specifications, Version 2.0", RFC 2437, Oct 1998.
+
+   [PFKEY]    McDonald, D., Metz, C., and Phan, B., "PF_KEY Key
+              Management API, Version 2", RFC 2367, July 1998.
+
+   [REKEY]    Tim Jenkins, "IPsec Re-keying Issues", <draft-jenkins-
+              ipsec-rekeying-06.txt>, 2 May 2000 (draft expired, work no
+              longer in progress).
+
+   [REPLAY]   Krywaniuk, A., "Using Isakmp Message Ids for Replay
+              Protection", <draft-krywaniuk-ipsec-antireplay-00.txt>, 9
+              July 2001 (work in progress).
+
+   [RSA]      Rivest, R.L., Shamir, A., and Adleman, L., "A Method for
+              Obtaining Digital Signatures and Public-Key
+              Cryptosystems", Communications of the ACM v21n2, Feb 1978,
+              p. 120.
+
+   [SCHNEIER] Bruce Schneier, "Applied Cryptography", 2nd ed., Wiley
+              1996, ISBN 0-471-11709-9.
+
+   [SECFAIL]  Karn, P., and Simpson, W., "ICMP Security Failures
+              Messages", RFC 2521, March 1999.
+
+Authors' Addresses
+
+   Henry Spencer
+   SP Systems
+   Box 280 Stn. A
+   Toronto, Ont. M5W1B2
+   Canada
+
+   henry@spsystems.net
+   416-690-6561
+
+
+
+
+Spencer & Redelmeier                                           [Page 20]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+   D. Hugh Redelmeier
+   Mimosa Systems Inc.
+   29 Donino Ave.
+   Toronto, Ont. M4N2W6
+   Canada
+
+   hugh@mimosa.com
+   416-482-8253
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Spencer & Redelmeier                                           [Page 21]
+
+Internet Draft          IKE Implementation Issues            26 Feb 2002
+
+
+Full Copyright Statement
+
+   Copyright (C) The Internet Society 2002. All Rights Reserved.
+
+   This document and translations of it may be copied and furnished to
+   others, and derivative works that comment on or otherwise explain it
+   or assist in its implmentation may be prepared, copied, published and
+   distributed, in whole or in part, without restriction of any kind,
+   provided that the above copyright notice and this paragraph are
+   included on all such copies and derivative works.  However, this
+   document itself may not be modified in any way, such as by removing
+   the copyright notice or references to the Internet Society or other
+   Internet organizations, except as needed for the  purpose of
+   developing Internet standards in which case the procedures for
+   copyrights defined in the Internet Standards process must be
+   followed, or as required to translate it into languages other than
+   English.
+
+   The limited permissions granted above are perpetual and will not be
+   revoked by the Internet Society or its successors or assigns.
+
+   This document and the information contained herein is provided on an
+   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
+   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
+   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
+   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
+   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Spencer & Redelmeier                                           [Page 22]
+
diff --git a/doc/examples b/doc/examples
new file mode 100644
index 000000000..315049b04
--- /dev/null
+++ b/doc/examples
@@ -0,0 +1,182 @@
+# sample connections
+# This file is RCSID $Id: examples,v 1.1 2004/03/15 20:35:21 as Exp $
+
+
+
+# basic configuration
+config setup
+	# THIS SETTING MUST BE CORRECT or almost nothing will work.
+	interfaces="ipsec0=eth1 ipsec1=ppp0"
+	# Debug-logging controls:  "none" for (almost) none, "all" for lots.
+	klipsdebug=none
+	plutodebug=none
+	# Manual connections to be started at startup.
+	manualstart="test1 test2"
+	# Auto connections to be loaded into Pluto at startup.
+	plutoload="samplehth samplefire"
+	# Auto connections to be started at startup.
+	plutostart=samplefire
+
+
+
+# defaults for subsequent connection descriptions
+conn %default
+	# How persistent to be in (re)keying negotiations (0 means very).
+	keyingtries=0
+	# Parameters for manual-keying testing (DON'T USE OPERATIONALLY).
+	spi=0x200
+	esp=3des-md5-96
+	espenckey=0x01234567_89abcdef_02468ace_13579bdf_12345678_9abcdef0
+	espauthkey=0x12345678_9abcdef0_2468ace0_13579bdf
+	# key lifetime (before automatic rekeying)
+	keylife=8h
+
+
+
+# sample connection
+conn sample
+	# Left security gateway and subnet behind it.
+	left=10.0.0.1
+	leftsubnet=172.16.0.0/24
+	# Right security gateway and subnet behind it.
+	right=10.12.12.1
+	rightsubnet=192.168.0.0/24
+	# Authorize this connection, but don't actually start it, at startup.
+	auto=add
+
+# sample tunnel (manually or automatically keyed)
+# Here we just use ESP for both encryption and authentication, which is
+# the simplest and often the best method.
+conn sample
+	# left security gateway (public-network address)
+	left=10.0.0.1
+	# next hop to reach right
+	leftnexthop=10.44.55.66
+	# subnet behind left (omit if left end of the tunnel is just the s.g.)
+	leftsubnet=172.16.0.0/24
+	# right s.g., subnet behind it, and next hop to reach left
+	right=10.12.12.1
+	rightnexthop=10.88.77.66
+	rightsubnet=192.168.0.0/24
+	# (manual) SPI number
+	spi=0x200
+	# (manual) encryption/authentication algorithm and parameters to it
+	esp=3des-md5-96
+	espenckey=[192 bits]
+	espauthkey=[128 bits]
+
+# In the remaining examples, deviations from the sample-tunnel configuration
+# are marked with ###.
+
+# sample host-to-host tunnel (no subnets)
+# Here we assume (for purposes of illustration) that the hosts talk directly
+# to each other, so we don't need next-hop settings.
+conn samplehth
+	### left host (public-network address)
+	left=10.0.0.1
+	### next hop to reach right
+	leftnexthop=
+	### right host
+	right=10.12.12.1
+	### next hop to reach left
+	rightnexthop=
+	### (manual) SPI number
+	spi=0x300
+	# (manual) encryption/authentication algorithm and parameters to it
+	esp=3des-md5-96
+	espenckey=[192 bits]
+	espauthkey=[128 bits]
+
+# sample hybrid tunnel, with a host on one end and a subnet (behind a
+# security gateway) on the other
+# This case is also sometimes called "road warrior".
+conn samplehyb
+	### left host (public-network address)
+	left=10.0.0.1
+	# next hop to reach right
+	leftnexthop=10.44.55.66
+	# subnet behind left
+	leftsubnet=172.16.0.0/24
+	### right host, and next hop to reach left
+	right=10.12.12.1
+	rightnexthop=10.88.77.66
+	### (manual) SPI number
+	spi=0x400
+	# (manual) encryption/authentication algorithm and parameters to it
+	esp=3des-md5-96
+	espenckey=[192 bits]
+	espauthkey=[128 bits]
+
+# sample firewall-penetrating tunnel
+# Here we assume that firewalling is being done on the left side.
+conn samplefire
+	# left security gateway (public-network address)
+	left=10.0.0.1
+	# next hop to reach right
+	leftnexthop=10.44.55.66
+	# subnet behind left (omit if left end of the tunnel is just the s.g.)
+	leftsubnet=172.16.0.0/24
+	### left is firewalling for its subnet
+	leftfirewall=yes
+	# right s.g., subnet behind it, and next hop to reach left
+	right=10.12.12.1
+	rightnexthop=10.88.77.66
+	rightsubnet=192.168.0.0/24
+	### (manual) SPI number
+	spi=0x500
+	# (manual) encryption/authentication algorithm and parameters to it
+	esp=3des-md5-96
+	espenckey=[192 bits]
+	espauthkey=[128 bits]
+
+# sample transport-mode connection (which can only be host-to-host)
+# Here we use the whole nine yards, with encryption done by ESP and
+# authentication by AH; this perhaps is slightly preferable for transport
+# mode, where the IP headers are exposed.
+conn sampletm
+	### transport mode rather than tunnel
+	type=transport
+	### left host (public-network address)
+	left=10.0.0.1
+	# next hop to reach right
+	leftnexthop=10.44.55.66
+	### right host, and next hop to reach left
+	right=10.12.12.1
+	rightnexthop=10.88.77.66
+	### (manual) SPI number
+	spi=0x600
+	### (manual) encryption algorithm and parameters to it
+	esp=3des
+	espenckey=[192 bits]
+	### (manual) authentication algorithm and parameters to it
+	ah=hmac-md5
+	ahkey=[128 bits]
+	### (auto) authentication control
+	auth=ah
+
+# sample description with keys split out into a separate section
+# Normally the key section would go in a separate file, with tighter
+# permissions set on it.
+conn samplesep
+	# left security gateway (public-network address)
+	left=10.0.0.1
+	# next hop to reach right
+	leftnexthop=10.44.55.66
+	# subnet behind left (omit if left end of the tunnel is just the s.g.)
+	leftsubnet=172.16.0.0/24
+	# right s.g., subnet behind it, and next hop to reach left
+	right=10.12.12.1
+	rightnexthop=10.88.77.66
+	rightsubnet=192.168.0.0/24
+	### (manual) SPI number
+	spi=0x700
+	# (manual) encryption/authentication algorithm and parameters to it
+	esp=3des-md5-96
+	also=samplesep-keys
+
+# keys for the previous section
+# Normally this would go in a separate file, picked up using an include line,
+# to allow keeping the keys confidential.
+conn samplesep-keys
+	espenckey=[192 bits]
+	espauthkey=[128 bits]
diff --git a/doc/faq.html b/doc/faq.html
new file mode 100644
index 000000000..b0fed502e
--- /dev/null
+++ b/doc/faq.html
@@ -0,0 +1,2339 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
+H5 { font-family: sans-serif }
+H6 { font-family: sans-serif }
+SUB { font-size: smaller }
+SUP { font-size: smaller }
+PRE { font-family: monospace }
+--></STYLE>
+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="policygroups.html">Previous</A>
+<A HREF="manpages.html">Next</A>
+<HR>
+<H1><A NAME="5">FreeS/WAN FAQ</A></H1>
+<P>This is a collection of questions and answers, mostly taken from the
+ FreeS/WAN<A href="mail.html"> mailing list</A>. See the project<A href="http://www.freeswan.org/">
+ web site</A> for more information. All the FreeS/WAN documentation is
+ online there.</P>
+<P>Contributions to the FAQ are welcome. Please send them to the project<A
+href="mail.html"> mailing list</A>.</P>
+<HR>
+<H2><A name="questions">Index of FAQ questions</A></H2>
+<UL>
+<LI><A href="#whatzit">What is FreeS/WAN?</A></LI>
+<LI><A href="#problems">How do I report a problem or seek help?</A></LI>
+<LI><A href="#generic">Can I get ...</A>
+<UL>
+<LI><A href="#lemme_out">... an off-the-shelf system that includes
+ FreeS/WAN?</A></LI>
+<LI><A href="#contractor">... contractors or staff who know FreeS/WAN?</A>
+</LI>
+<LI><A href="#commercial">... commercial support?</A></LI>
+</UL>
+</LI>
+<LI><A href="#release">Release questions</A>
+<UL>
+<LI><A href="#rel.current">What is the current release?</A></LI>
+<LI><A href="#relwhen">When is the next release?</A></LI>
+<LI><A href="#rel.bugs">Are there known bugs in the current release?</A></LI>
+</UL>
+</LI>
+<LI><A href="mod_cons">Modifications and contributions</A>
+<UL>
+<LI><A href="#modify.faq">Can I modify FreeS/WAN to ...?</A></LI>
+<LI><A href="#contrib.faq">Can I contribute to the project?</A></LI>
+<LI><A href="#ddoc.faq">Is there detailed design documentation?</A></LI>
+</UL>
+</LI>
+<LI><A href="#interact">Will FreeS/WAN work in my environment?</A>
+<UL>
+<LI><A href="#interop.faq">Can FreeS/WAN talk to ... ?</A></LI>
+<LI><A href="#old_to_new">Can different FreeS/WAN versions talk to each
+ other?</A></LI>
+<LI><A href="#faq.bandwidth">Is there a limit on throughput?</A></LI>
+<LI><A href="#faq.number">Is there a limit on number of connections?</A></LI>
+<LI><A href="#faq.speed">Is a ... fast enough to handle FreeS/WAN with
+ my loads?</A></LI>
+</UL>
+</LI>
+<LI><A href="#work_on">Will FreeS/WAN work on ...</A>
+<UL>
+<LI><A href="#versions">... my version of Linux?</A></LI>
+<LI><A href="#nonIntel.faq">... non-Intel CPUs?</A></LI>
+<LI><A href="#multi.faq">... multiprocessors?</A></LI>
+<LI><A href="#k.old">... an older kernel?</A></LI>
+<LI><A href="#k.versions">... the latest kernel version?</A></LI>
+<LI><A href="#interface.faq">... unusual network hardware?</A></LI>
+<LI><A href="#vlan">... a VLAN (802.1q) network?</A></LI>
+</UL>
+</LI>
+<LI><A href="#features.faq">Does FreeS/WAN support ...</A>
+<UL>
+<LI><A href="#VPN.faq">... site-to-site VPN applications</A></LI>
+<LI><A href="#warrior.faq">... remote users connecting to a LAN</A></LI>
+<LI><A href="#road.shared.possible">... remote users using shared secret
+ authentication?</A></LI>
+<LI><A href="#wireless.faq">... wireless networks</A></LI>
+<LI><A href="#PKIcert">... X.509 or other PKI certificates?</A></LI>
+<LI><A href="#Radius">... user authentication (Radius, SecureID, Smart
+ Card ...)?</A></LI>
+<LI><A href="#NATtraversal">... NAT traversal</A></LI>
+<LI><A href="#virtID">... assigning a &quot;virtual identity&quot; to a remote
+ system?</A></LI>
+<LI><A href="#noDES.faq">... single DES encryption?</A></LI>
+<LI><A href="#AES.faq">... AES encryption?</A></LI>
+<LI><A href="#other.cipher">... other encryption algorithms?</A></LI>
+</UL>
+</LI>
+<LI><A href="#canI">Can I ...</A>
+<UL>
+<LI><A href="#policy.preconfig">...use policy groups along with
+ explicitly configured connections?</A></LI>
+<LI><A href="#policy.off">...turn off policy groups?</A></LI>
+
+<!--
+      <li><a href="#policy.otherinterface">...use policy groups
+      on an interface other than <VAR>%defaultroute</VAR>?</a></li>
+-->
+<LI><A href="#reload">... reload connection info without restarting?</A></LI>
+<LI><A href="#masq.faq">... use several masqueraded subnets?</A></LI>
+<LI><A href="#dup_route">... use subnets masqueraded to the same
+ addresses?</A></LI>
+<LI><A href="#road.masq">... assign a road warrior an address on my net
+ (a virtual identity)?</A></LI>
+<LI><A href="#road.many">... support many road warriors with one
+ gateway?</A></LI>
+<LI><A href="#road.PSK">... have many road warriors using shared secret
+ authentication?</A></LI>
+<LI><A href="#QoS">... use Quality of Service routing with FreeS/WAN?</A>
+</LI>
+<LI><A href="#deadtunnel">... recognise dead tunnels and shut them down?</A>
+</LI>
+<LI><A href="#demanddial">... build IPsec tunnels over a demand-dialed
+ link?</A></LI>
+<LI><A href="#GRE">... build GRE, L2TP or PPTP tunnels over IPsec?</A></LI>
+<LI><A href="#NetBIOS">... use Network Neighborhood (Samba, NetBIOS)
+ over IPsec?</A></LI>
+</UL>
+</LI>
+<LI><A href="#setup.faq">Life's little mysteries</A>
+<UL>
+<LI><A href="#cantping">I cannot ping ....</A></LI>
+<LI><A href="#forever">It takes forever to ...</A></LI>
+<LI><A href="#route">I send packets to the tunnel with route(8) but they
+ vanish</A></LI>
+<LI><A href="#down_route">When a tunnel goes down, packets vanish</A></LI>
+<LI><A href="#firewall_ate">The firewall ate my packets!</A></LI>
+<LI><A href="#dropconn">Dropped connections</A></LI>
+<LI><A href="#defaultroutegone">Disappearing %defaultroute</A></LI>
+<LI><A href="#tcpdump.faq">TCPdump on the gateway shows strange things</A>
+</LI>
+<LI><A href="#no_trace">Traceroute does not show anything between the
+ gateways</A></LI>
+</UL>
+</LI>
+<LI><A href="#man4debug">Testing in stages (or .... works but ...
+ doesn't)</A>
+<UL>
+<LI><A href="#nomanual">Manually keyed connections don't work</A></LI>
+<LI><A href="#spi_error">One manual connection works, but second one
+ fails</A></LI>
+<LI><A href="#man_no_auto">Manual connections work, but automatic keying
+ doesn't</A></LI>
+<LI><A href="#nocomp">IPsec works, but connections using compression
+ fail</A></LI>
+<LI><A href="#pmtu.broken">Small packets work, but large transfers fail</A>
+</LI>
+<LI><A href="#subsub">Subnet-to-subnet works, but tests from the
+ gateways don't</A></LI>
+</UL>
+</LI>
+<LI><A href="#compile.faq">Compilation problems</A>
+<UL>
+<LI><A href="#gmp.h_missing">gmp.h: No such file or directory</A></LI>
+<LI><A href="#noVM">... virtual memory exhausted</A></LI>
+</UL>
+</LI>
+<LI><A href="#error">Interpreting error messages</A>
+<UL>
+<LI><A href="#route-client">route-client (or host) exited with status 7</A>
+</LI>
+<LI><A href="#unreachable">SIOCADDRT:Network is unreachable</A></LI>
+<LI><A href="#modprobe">ipsec_setup: modprobe: Can't locate moduleipsec</A>
+</LI>
+<LI><A href="#noKLIPS">ipsec_setup: Fatal error, kernel appears to lack
+ KLIPS</A></LI>
+<LI><A href="#noDNS">ipsec_setup: ... failure to fetch key for ... from
+ DNS</A></LI>
+<LI><A href="#dup_address">ipsec_setup: ... interfaces ... and ... share
+ address ...</A></LI>
+<LI><A href="#kflags">ipsec_setup: Cannot adjust kernel flags</A></LI>
+<LI><A href="#message_num">Message numbers (MI3, QR1, et cetera) in
+ Pluto messages</A></LI>
+<LI><A href="#conn_name">Connection names in Pluto error messages</A></LI>
+<LI><A href="#cantorient">Pluto: ... can't orient connection</A></LI>
+<LI><A href="#no.interface">... we have no ipsecN interface for either
+ end of this connection</A></LI>
+<LI><A href="#noconn">Pluto: ... no connection is known</A></LI>
+<LI><A href="#nosuit">Pluto: ... no suitable connection ...</A></LI>
+<LI><A href="#noconn.auth">Pluto: ... no connection has been authorized</A>
+</LI>
+<LI><A href="#noDESsupport">Pluto: ... OAKLEY_DES_CBC is not supported.</A>
+</LI>
+<LI><A href="#notransform">Pluto: ... no acceptable transform</A></LI>
+<LI><A href="#rsasigkey">rsasigkey dumps core</A></LI>
+<LI><A href="#sig4">!Pluto failure!: ... exited with ... signal 4</A></LI>
+<LI><A href="#econnrefused">ECONNREFUSED error message</A></LI>
+<LI><A href="#no_eroute">klips_debug: ... no eroute!</A></LI>
+<LI><A href="#SAused">... trouble writing to /dev/ipsec ... SA already
+ in use</A></LI>
+<LI><A href="#ignore">... ignoring ... payload</A></LI>
+<LI><A href="#unknown_rightcert">unknown parameter name &quot;rightcert&quot;</A></LI>
+</UL>
+</LI>
+<LI><A href="#spam">Why don't you restrict the mailing lists to reduce
+ spam?</A></LI>
+</UL>
+<HR>
+<H2><A name="whatzit">What is FreeS/WAN?</A></H2>
+<P>FreeS/WAN is a Linux implementation of the<A href="glossary.html#IPSEC">
+ IPsec</A> protocols, providing security services at the IP (Internet
+ Protocol) level of the network.</P>
+<P>For more detail, see our<A href="intro.html"> introduction</A>
+ document or the FreeS/WAN project<A href="http://www.freeswan.org/">
+ web site</A>.</P>
+<P>To start setting it up, go to our<A href="quickstart.html">
+ quickstart guide</A>.</P>
+<P>Our<A href="web.html"> web links</A> document has information on<A href="web.html#implement">
+ IPsec for other systems</A>.</P>
+<H2><A name="problems">How do I report a problem or seek help?</A></H2>
+<DL>
+<DT>Read our<A href="trouble.html"> troubleshooting</A> document.</DT>
+<DD>
+<P>It may guide you to a solution. If not, see its<A href="trouble.html#prob.report">
+ problem reporting</A> section.</P>
+<P>Basically, what it says is<STRONG> give us the output from<VAR> ipsec
+ barf</VAR> from both gateways</STRONG>. Without full information, we
+ cannot diagnose a problem. However,<VAR> ipsec barf</VAR> produces a
+ lot of output. If at all possible,<STRONG> please make barfs accessible
+ via the web or FTP</STRONG> rather than sending enormous mail messages.</P>
+</DD>
+<DT><STRONG>Use the<A href="mail.html"> users mailing list</A> for
+ problem reports</STRONG>, rather than mailing developers directly.</DT>
+<DD>
+<UL>
+<LI>This gives you access to more expertise, including users who may
+ have encountered and solved the same problems.</LI>
+<LI>It is more likely to get a quick response. Developers may get behind
+ on email, or even ignore it entirely for a while, but a list message
+ (given a reasonable Subject: line) is certain to be read by a fair
+ number of people within hours.</LI>
+<LI>It may also be important because of<A href="politics.html#exlaw">
+ cryptography export laws</A>. A US citizen who provides technical
+ assistance to foreign cryptographic work might be charged under the
+ arms export regulations. Such a charge would be easier to defend if the
+ discussion took place on a public mailing list than if it were done in
+ private mail.</LI>
+</UL>
+</DD>
+<DT>Try irc.freenode.net#freeswan.</DT>
+<DD>
+<P>FreeS/WAN developers, volunteers and users can often be found there.
+ Be patient and be prepared to provide lots of information to support
+ your question.</P>
+<P>If your question was really interesting, and you found an answer,
+ please share that with the class by posting to the<A href="mail.html">
+ users mailing list</A>. That way others with the same problem can find
+ your answer in the archives.</P>
+</DD>
+<DT>Premium support is also available.</DT>
+<DD>
+<P>See the next several questions.</P>
+</DD>
+</DL>
+<H2><A name="generic">Can I get ...</A></H2>
+<H3><A name="lemme_out">Can I get an off-the-shelf system that includes
+ FreeS/WAN?</A></H3>
+<P>There are a number of Linux distributions or firewall products which
+ include FreeS/WAN. See this<A href="intro.html#products"> list</A>.
+ Using one of these, chosen to match your requirements and budget, may
+ save you considerable time and effort.</P>
+<P>If you don't know your requirements, start by reading Schneier's<A href="biblio.html#secrets">
+ Secrets and Lies</A>. That gives the best overview of security issues I
+ have seen. Then consider hiring a consultant (see next question) to
+ help define your requirements.</P>
+<H3><A name="consultant">Can I hire consultants or staff who know
+ FreeS/WAN?</A></H3>
+<P>If you want the help of a contractor, or to hire staff with FreeS/WAN
+ expertise, you could:</P>
+<UL>
+<LI>check availability in your area through your local Linux User Group
+ (<A href="http://lugww.counter.li.org/">LUG Index</A>)</LI>
+<LI>try asking on our<A href="mail.html"> mailing list</A></LI>
+</UL>
+<P>For companies offerring support, see the next question.</P>
+<H3><A name="commercial">Can I get commercial support?</A></H3>
+<P>Many of the distributions or firewall products which include
+ FreeS/WAN (see this<A href="intro.html#products"> list</A>) come with
+ commercial support or have it available as an option.</P>
+<P>Various companies specialize in commercial support of open source
+ software. Our project leader was a founder of the first such company,
+ Cygnus Support. It has since been bought by<A href="http://www.redhat.com">
+ Redhat</A>. Another such firm is<A href="http://www.linuxcare.com">
+ Linuxcare</A>.</P>
+<H2><A name="release">Release questions</A></H2>
+<H3><A name="rel.current">What is the current release?</A></H3>
+<P>The current release is the highest-numbered tarball on our<A href="ftp://ftp.xs4all.nl/pub/crypto/freeswan">
+ distribution site</A>. Almost always, any of<A href="intro.html#mirrors">
+ the mirrors</A> will have the same file, though perhaps not for a day
+ or so after a release.</P>
+<P>Unfortunately, the web site is not always updated as quickly as it
+ should be.</P>
+<H3><A name="relwhen">When is the next release?</A></H3>
+<P>We try to do a release approximately every six to eight weeks.</P>
+<P>If pre-release tests fail and the fix appears complex, or more
+ generally if the code does not appear stable when a release is
+ scheduled, we will just skip that release.</P>
+<P>For serious bugs, we may bring out an extra bug-fix release. These
+ get numbers in the normal release series. For example, there was a bug
+ found in FreeS/WAN 1.6, so we did another release less than two weeks
+ later. The bug-fix release was called 1.7.</P>
+<H3><A name="rel.bugs">Are there known bugs in the current release?</A></H3>
+<P>Any problems we are aware of at the time of a release are documented
+ in the<A href="../BUGS"> BUGS</A> file for that release. You should
+ also look at the<A href="../CHANGES"> CHANGES</A> file.</P>
+<P>Bugs discovered after a release are discussed on the<A href="mail.html">
+ mailing lists</A>. The easiest way to check for any problems in the
+ current code would be to peruse the<A href="http://lists.freeswan.org/pipermail/briefs">
+ List In Brief</A>.</P>
+<H2><A name="mod_cons">Modifications and contributions</A></H2>
+<H3><A name="modify.faq">Can I modify FreeS/WAN to ...?</A></H3>
+<P>You are free to modify FreeS/WAN in any way. See the discussion of<A href="intro.html#licensing">
+ licensing</A> in our introduction document.</P>
+<P>Before investing much energy in any such project, we suggest that you</P>
+<UL>
+<LI>check the list of<A href="web.html#patch"> existing patches</A></LI>
+<LI>post something about your project to the<A href="mail.html"> design
+ mailing list</A></LI>
+</UL>
+<P>This may prevent duplicated effort, or lead to interesting
+ collaborations.</P>
+<H3><A name="contrib.faq">Can I contribute to the project?</A></H3>
+ In general, we welcome contributions from the community. Various
+ contributed patches, either to fix bugs or to add features, have been
+ incorporated into our distribution. Other patches, not yet included in
+ the distribution, are listed in our<A href="web.html#patch"> web links</A>
+ section.
+<P>Users have also contributed heavily to documentation, both by
+ creating their own<A href="intro.html#howto"> HowTos</A> and by posting
+ things on the<A href="mail.html"> mailing lists</A> which I have quoted
+ in these HTML docs.</P>
+<P>There are, however, some caveats.</P>
+<P>FreeS/WAN is being implemented in Canada, by Canadians, largely to
+ ensure that is it is entirely free of export restrictions. See this<A href="politics.html#status">
+ discussion</A>. We<STRONG> cannot accept code contributions from US
+ residents or citizens</STRONG>, not even one-line bugs fixes. The
+ reasons for this were recently discussed extensively on the mailing
+ list, in a thread starting<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/01/msg00111.html">
+ here</A>.</P>
+<P>Not all contributions are of interest to us. The project has a set of
+ fairly ambitious and quite specific goals, described in our<A href="intro.html#goals">
+ introduction</A>. Contributions that lead toward these goals are likely
+ to be welcomed enthusiastically. Other contributions may be seen as
+ lower priority, or even as a distraction.</P>
+<P>Discussion of possible contributions takes place on the<A href="mail.html">
+ design mailing list</A>.</P>
+<H3><A name="ddoc.faq">Is there detailed design documentation?</A></H3>
+ There are:
+<UL>
+<LI><A href="rfc.html">RFCs</A> specifying the protocols we implement</LI>
+<LI><A href="manpages.html">man pages</A> for our utilities, library
+ functions and file formats</LI>
+<LI>comments in the source code</LI>
+<LI><A href="index.html">HTML documentation</A> written primarily for
+ users</LI>
+<LI>archived discussions from the<A href="mail.html"> mailing lists</A></LI>
+<LI>other papers mentioned in our<A href="intro.html#applied">
+ introduction</A></LI>
+</UL>
+<P>The only formal design documents are a few papers in the last
+ category above. All the other categories, however, have things to say
+ about design as well.</P>
+<H2><A name="interact">Will FreeS/WAN work in my environment?</A></H2>
+<H3><A name="interop.faq">Can FreeS/WAN talk to ...?</A></H3>
+<P>The IPsec protocols are designed to support interoperation. In
+ theory, any two IPsec implementations should be able to talk to each
+ other. In practice, it is considerably more complex. We have a whole<A href="interop.html">
+ interoperation document</A> devoted to this problem.</P>
+<P>An important part of that document is links to the many<A href="interop.html#otherpub">
+ user-written HowTos</A> on interoperation between FreeS/WAN and various
+ other implementations. Often the users know more than the developers
+ about these issues (and almost always more than me :-), so these
+ documents may be your best resource.</P>
+<H3><A name="old_to_new">Can different FreeS/WAN versions talk to each
+ other?</A></H3>
+<P>Linux FreeS/WAN can interoperate with many IPsec implementations,
+ including earlier versions of Linux FreeS/WAN itself.</P>
+<P>In a few cases, there are some complications. See our<A href="interop.html#oldswan">
+ interoperation</A> document for details.</P>
+<H3><A name="faq.bandwidth">Is there a limit on throughput?</A></H3>
+<P>There is no hard limit, but see below.</P>
+<H3><A name="faq.number">Is there a limit on number of tunnels?</A></H3>
+<P>There is no hard limit, but see next question.</P>
+<H3><A name="faq.speed">Is a ... fast enough to handle FreeS/WAN with my
+ loads?</A></H3>
+<P>A quick summary:</P>
+<DL>
+<DT>Even a limited machine can be useful</DT>
+<DD>A 486 can handle a T1, ADSL or cable link, though the machine may be
+ breathing hard.</DD>
+<DT>A mid-range PC (say 800 MHz with good network cards) can do a lot of
+ IPsec</DT>
+<DD>With up to roughly 50 tunnels and aggregate bandwidth of 20 Megabits
+ per second, it willl have cycles left over for other tasks.</DD>
+<DT>There are limits</DT>
+<DD>Even a high end CPU will not come close to handling a fully loaded
+ 100 Mbit/second Ethernet link.
+<P>Beyond about 50 tunnels it needs careful management.</P>
+</DD>
+</DL>
+<P>See our<A href="performance.html"> FreeS/WAN performance</A> document
+ for details.</P>
+<H2><A name="work_on">Will FreeS/WAN work on ... ?</A></H2>
+<H3><A name="versions">Will FreeS/WAN run on my version of Linux?</A></H3>
+<P>We build and test on Redhat distributions, but FreeS/WAN runs just
+ fine on several other distributions, sometimes with minor fiddles to
+ adapt to the local environment. Details are in our<A href="compat.html#otherdist">
+ compatibility</A> document. Also, some distributions or products come
+ with<A href="intro.html#products"> FreeS/WAN included</A>.</P>
+<H3><A name="nonIntel.faq">Will FreeS/WAN run on non-Intel CPUs?</A></H3>
+<P>FreeS/WAN is<STRONG> intended to run on all CPUs Linux supports</STRONG>
+. We know of it being used in production on x86, ARM, Alpha and MIPS. It
+ has also had successful tests on PPC and SPARC, though we don't know of
+ actual use there. Details are in our<A href="compat.html#CPUs">
+ compatibility</A> document.</P>
+<H3><A name="multi.faq">Will FreeS/WAN run on multiprocessors?</A></H3>
+<P>FreeS/WAN is designed to work on any SMP architecture Linux supports,
+ and has been tested successfully on at least dual processor Intel
+ architecture machines. Details are in our<A href="compat.html#multiprocessor">
+ compatibility</A> document.</P>
+<H3><A name="k.old">Will FreeS/WAN work on an older kernel?</A></H3>
+<P>It might, but we strongly recommend using a recent 2.2 or 2.4 series
+ kernel. Sometimes the newer versions include security fixes which can
+ be quite important on a gateway.</P>
+<P>Also, we use recent kernels for development and testing, so those are
+ better tested and, if you do encounter a problem, more easily
+ supported. If something breaks applying recent FreeS/WAN patches to an
+ older kernel, then &quot;update your kernel&quot; is almost certain to be the
+ first thing we suggest. It may be the only suggestion we have.</P>
+<P>The precise kernel versions supported by a particular FreeS/WAN
+ release are given in the<A href="XX"> README</A> file of that release.</P>
+<P>See the following question for more on kernels.</P>
+<H3><A name="k.versions">Will FreeS/WAN run on the latest kernel
+ version?</A></H3>
+<P>Sometimes yes, but quite often, no.</P>
+<P>Kernel versions supported are given in the<A href="../README"> README</A>
+ file of each FreeS/WAN release. Typically, they are whatever production
+ kernels were current at the time of our release (or shortly before; we
+ might release for kernel<VAR> n</VAR> just as Linus releases<VAR> n+1</VAR>
+). Often FreeS/WAN will work on slightly later kernels as well, but of
+ course this cannot be guaranteed.</P>
+<P>For example, FreeS/WAN 1.91 was released for kernels 2.2.19 or 2.4.5,
+ the current kernels at the time. It also worked on 2.4.6, 2.4.7 and
+ 2.4.8, but 2.4.9 had changes that caused compilation errors if it was
+ patched with FreeS/WAN 1.91.</P>
+<P>When such changes appear, we put a fix in the FreeS/WAN snapshots,
+ and distribute it with our next release. However, this is not a high
+ priority for us, and it may take anything from a few days to several
+ weeks for such a problem to find its way to the top of our kernel
+ programmer's To-Do list. In the meanwhile, you have two choices:</P>
+<UL>
+<LI>either stick with a slightly older kernel, even if it is not the
+ latest and greatest. This is recommended for production systems; new
+ versions may have new bugs.</LI>
+<LI>or fix the problem yourself and send us a patch, via the<A href="mail.html">
+ Users mailing list</A>.</LI>
+</UL>
+<P>We don't even try to keep up with kernel changes outside the main 2.2
+ and 2.4 branches, such as the 2.4.x-ac patched versions from Alan Cox
+ or the 2.5 series of development kernels. We'd rather work on
+ developing the FreeS/WAN code than on chasing these moving targets. We
+ are, however, happy to get patches for problems discovered there.</P>
+<P>See also the<A href="install.html#choosek"> Choosing a kernel</A>
+ section of our installation document.</P>
+<H3><A name="interface.faq">Will FreeS/WAN work on unusual network
+ hardware?</A></H3>
+<P>IPsec is designed to work over any network that IP works over, and
+ FreeS/WAN is intended to work over any network interface hardware that
+ Linux supports.</P>
+<P>If you have working IP on some unusual interface -- perhaps Arcnet,
+ Token Ring, ATM or Gigabit Ethernet -- then IPsec should &quot;just work&quot;.</P>
+<P>That said, practice is sometimes less tractable than theory. Our
+ testing is done almost entirely on:</P>
+<UL>
+<LI>10 or 100 Mbit Ethernet</LI>
+<LI>ADSL or cable connections, with and without PPPoE</LI>
+<LI>IEEE 802.11 wireless LANs (see<A href="#wireless.faq"> below</A>)</LI>
+</UL>
+<P>If you have some other interface, especially an uncommon one, it is
+ entirely possible you will get bitten either by a FreeS/WAN bug which
+ our testing did not turn up, or by a bug in the driver that shows up
+ only with our loads.</P>
+<P>If IP works on your interface and FreeS/WAN doesn't, seek help on the<A
+href="mail.html"> mailing lists</A>.</P>
+<P>Another FAQ section describes<A href="#pmtu.broken"> MTU problems</A>
+. These are a possibility for some interfaces.</P>
+<H3><A name="vlan">Will FreeS/WAN work on a VLAN (802.1q) network?</A></H3>
+<P> Yes, FreeSwan works fine, though some network drivers have problems
+ with jumbo sized ethernet frames. If you used interfaces=%defaultroute
+ you do not need to change anything, but if you specified an interface
+ (eg eth0) then remember you must change that to reflect the VLAN
+ interface (eg eth0.2 for VLAN ID 2).</P>
+<P> The &quot;eepro100&quot; module is known to be broken, use the e100 driver for
+ those cards instead (included in 2.4 as 'alternative driver' for the
+ Intel EtherExpressPro/100.</P>
+<P> You do not need to change any MTU setting (those are workarounds
+ that are only needed for buggy drivers)</P>
+<P><EM>This FAQ contributed by Paul Wouters.</EM></P>
+<H2><A name="features.faq">Does FreeS/WAN support ...</A></H2>
+<P>For a discussion of which parts of the IPsec specifications FreeS/WAN
+ does and does not implement, see our<A href="compat.html#spec">
+ compatibility</A> document.</P>
+<P>For information on some often-requested features, see below.</P>
+<H3><A name="VPN.faq"></A>Does FreeS/WAN support site-to-site VPN (<A HREF="glossary.html#VPN">
+Virtual Private Network</A>) applications?</H3>
+<P>Absolutely. See this FreeS/WAN-FreeS/WAN<A HREF="config.html">
+ configuration example</A>. If only one site is using FreeS/WAN, there
+ may be a relevant HOWTO on our<A HREF="interop.html"> interop page</A>.</P>
+<H3><A name="warrior.faq">Does FreeS/WAN support remote users connecting
+ to a LAN?</A></H3>
+<P>Yes. We call the remote users &quot;Road Warriors&quot;. Check out our
+ FreeS/WAN-FreeS/WAN<A HREF="config.html#config.rw"> Road Warrior
+ Configuration Example</A>.</P>
+<P>If your Road Warrior is a Windows or Mac PC, you may need to install
+ an IPsec implementation on that machine. Our<A HREF="interop.html">
+ interop</A> page lists many available brands, and features links to
+ several HOWTOs.</P>
+<H3><A name="road.shared.possible">Does FreeS/WAN support remote users
+ using shared secret authentication?</A></H3>
+<P><STRONG>Yes, but</STRONG> there are severe restrictions, so<STRONG>
+ we strongly recommend using</STRONG><A href="glossary.html#RSA"><STRONG>
+ RSA</STRONG></A><STRONG> keys for</STRONG><A href="glossary.html#authentication">
+<STRONG> authentication</STRONG></A><STRONG> instead</STRONG>.</P>
+<P>See this<A href="#road.PSK"> FAQ question</A>.</P>
+<H3><A name="wireless.faq">Does FreeS/WAN support wireless networks?</A></H3>
+<P>Yes, it is a common practice to use IPsec over wireless networks
+ because their built-in encryption,<A href="glossary.html#WEP"> WEP</A>,
+ is insecure.</P>
+<P>There is some<A href="adv_config.html#wireless.config"> discussion</A>
+ in our advanced configuration document. See also the<A HREF="http://www.wavesec.org">
+ WaveSEC site</A>.</P>
+<H3><A name="PKIcert">Does FreeS/WAN support X.509 or other PKI
+ certificates?</A></H3>
+<P>Vanilla FreeS/WAN does not support X.509, but Andreas Steffen and
+ others have provided a popular, well-supported X.509 patch.</P>
+<UL>
+<LI><A HREF="http://www.strongsec.com/freeswan">patch</A></LI>
+<LI><A HREF="http://www.freeswan.ca">Super FreeS/WAN</A> incorporates
+ this and other user-contributed patches.</LI>
+<LI> Kai Martius'<A HREF="http://www.strongsec.com/freeswan/install.htm">
+ X.509 Installation and Configuration Guide</A></LI>
+</UL>
+<P> Linux FreeS/WAN features<A HREF="quickstart.html"> Opportunistic
+ Encryption</A>, an alternative Public Key Infrastructure based on
+ Secure DNS.</P>
+<H3><A name="Radius">Does FreeS/WAN support user authentication (Radius,
+ SecureID, Smart Card...)?</A></H3>
+<P>Andreas Steffen's<A HREF="http://www.strongsec.com/freeswan"> X.509
+ patch</A> (v. 1.42+) supports Smart Cards. The patch does not ship with
+ vanilla FreeS/WAN, but will be incorporated into<A HREF="http://www.freeswan.ca/">
+ Super FreeS/WAN 2.01+</A>. The patch implements the PCKS#15
+ Cryptographic Token Information Format Standard, using the OpenSC
+ smartcard library functions.</P>
+<P>Older news:</P>
+<P>A user-supported patch to FreeS/WAN 1.3, for smart card style
+ authentication, is available on<A HREF="http://alcatraz.webcriminals.com/~bastiaan/ipsec">
+ Bastiaan's site</A>. It supports skeyid and ibutton. This patch is not
+ part of Super FreeS/WAN.</P>
+<P>For a while progress on this front was impeded by a lack of standard.
+ The IETF<A href="http://www.ietf.org/html.charters/ipsra-charter.html">
+ working group</A> has now nearly completed its recommended solution to
+ the problem; meanwhile several vendors have implemented various things.</P>
+
+<!--
+<p>The <a href="web.html#patch">patches</a> section of our web links document
+has links to some user work on this.</p>
+-->
+<P>Of course, there are various ways to avoid any requirement for user
+ authentication in IPsec. Consider the situation where road warriors
+ build IPsec tunnels to your office net and you are considering
+ requiring user authentication during tunnel negotiation. Alternatives
+ include:</P>
+<UL>
+<LI>If you can trust the road warrior machines, then set them up so that
+ only authorised users can create tunnels. If your road warriors use
+ laptops, consider the possibility of theft.</LI>
+<LI>If the tunnel only provides access to particular servers and you can
+ trust those servers, then set the servers up to require user
+ authentication.</LI>
+</UL>
+<P>If either of those is trustworthy, it is not clear that you need user
+ authentication in IPsec.</P>
+<H3><A name="NATtraversal">Does FreeS/WAN support NAT traversal?</A></H3>
+<P>Vanilla FreeS/WAN does not, but thanks to Mathieu Lafon and Arkoon
+ Network Security, there's a patch to support this.</P>
+<UL>
+<LI><A HREF="http://open-source.arkoon.net">patch and documentation</A></LI>
+<LI><A HREF="http://www.freeswan.ca">Super FreeS/WAN</A> incorporates
+ this and other user-contributed patches.</LI>
+</UL>
+<P>The NAT traversal patch has some issues with PSKs, so you may wish to
+ authenticate with RSA keys, or X.509 (requires a patch which is also
+ included in Super FreeS/WAN). Doing the latter also has advantages when
+ dealing with large numbers of clients who may be behind NAT; instead of
+ having to make an individual Roadwarrior connection for each virtual
+ IP, you can use the &quot;rightsubnetwithin&quot; parameter to specify a range.
+ See<A HREF="http://www.strongsec.com/freeswan/install.htm#section_4.4">
+ these<VAR> rightsubnetwithin</VAR> instructions</A>.</P>
+<H3><A name="virtID">Does FreeS/WAN support assigning a &quot;virtual
+ identity&quot; to a remote system?</A></H3>
+<P>Some IPsec implementations allow you to make the source address on
+ packets sent by a Road Warrior machine be something other than the
+ address of its interface to the Internet. This is sometimes described
+ as assigning a virtual identity to that machine.</P>
+<P>FreeS/WAN does not directly support this, but it can be done. See
+ this<A href="#road.masq"> FAQ question</A>.</P>
+<H3><A name="noDES.faq">Does FreeS/WAN support single DES encryption?</A>
+</H3>
+<P><STRONG>No</STRONG>, single DES is not used either at the<A href="glossary.html#IKE">
+ IKE</A> level for negotiating connections or at the<A href="glossary.html#IPsec">
+ IPsec</A> level for actually building them.</P>
+<P>Single DES is<A href="politics.html#desnotsecure"> insecure</A>. As
+ we see it, it is more important to deliver real security than to comply
+ with a standard which has been subverted into allowing use of
+ inadequate methods. See this<A href="politics.html#weak"> discussion</A>
+.</P>
+<P>If you want to interoperate with an IPsec implementation which offers
+ only DES, see our<A href="interop.html#noDES"> interoperation</A>
+ document.</P>
+<H3><A name="AES.faq">Does FreeS/WAN support AES encryption?</A></H3>
+<P><A href="glossary.html#AES">AES</A> is a new US government<A href="glossary.html#block">
+ block cipher</A> standard to replace the obsolete<A href="glossary.html#DES">
+ DES</A>.</P>
+<P>At time of writing (March 2002), the FreeS/WAN distribution does not
+ yet support AES but user-written<A href="web.html#patch"> patches</A>
+ are available to add it. Our kernel programmer is working on
+ integrating those patches into the distribution, and there is active
+ discussion of this on the design mailimg list.</P>
+<H3><A name="other.cipher">Does FreeS/WAN support other encryption
+ algorithms?</A></H3>
+<P>Currently<A href="glossary.html#3DES"> triple DES</A> is the only
+ cipher supported. AES will almost certainly be added (see previous
+ question), and it is likely that in the process we will also add the
+ other two AES finalists with open licensing, Twofish and Serpent.</P>
+<P>We are extremely reluctant to add other ciphers. This would make both
+ use and maintenance of FreeS/WAN more complex without providing any
+ clear benefit. Complexity is emphatically not desirable in a security
+ product.</P>
+<P>Various users have written patches to add other ciphers. We provide<A href="web.html#patch">
+ links</A> to these.</P>
+<H2><A name="canI">Can I ...</A></H2>
+<H3><A name="policy.preconfig">Can I use policy groups along with
+ explicitly configured connections?</A></H3>
+<P>Yes, you can, so long as you pay attention to the selection rule,
+ which can be summarized &quot;the most specific connection wins&quot;. We
+ describe the rule in our<A HREF="policygroups.html#policy.group.notes">
+ policy groups</A> document, and provide a more technical explanation in<A
+HREF="manpage.d/ipsec.conf.5.html"> man ipsec.conf</A>.</P>
+<P>A good guideline: If you have a regular connection defined in<VAR>
+ ipsec.conf</VAR>, ensure that a subset of that connection is not listed
+ in a less restrictive policy group. Otherwise, FreeS/WAN will use the
+ subset, with its more specific source/destination pair.</P>
+<P>Here's an example. Suppose you are the system administrator at
+ 192.0.2.2. You have this connection in ipsec.conf:<VAR> ipsec.conf</VAR>
+:</P>
+<PRE>conn net-to-net
+    left=192.0.2.2           # you are here
+    right=192.0.2.8
+    rightsubnet=192.0.2.96/27
+    ....
+</PRE>
+<P>If you then place a host or net within<VAR> rightsubnet</VAR>, (let's
+ say 192.0.2.98) in<VAR> private-or-clear</VAR>, you may find that
+ 192.0.2.2 at times communicates in the clear with 192.0.2.98. That's
+ consistent with the rule, but may be contrary to your expectations.</P>
+<P>On the other hand, it's safe to put a larger subnet in a less
+ restrictive policy group file. If<VAR> private-or-clear</VAR> contains
+ 192.0.2.0/24, then the more specific<VAR> net-to-net</VAR> connection
+ is used for any communication to 192.0.2.96/27. The more general policy
+ applies only to communication with hosts or subnets in 192.0.2.0/24
+ without a more specific policy or connection.</P>
+<H3><A name="policy.off">Can I turn off policy groups?</A></H3>
+<P>Yes. Use<A HREF="policygroups.html#disable_policygroups"> these
+ instructions</A>.</P>
+
+<!--
+<h3><a name="policy.otherinterface">Can I use policy groups
+ on an interface other than <VAR>%defaultroute</VAR>?</a></h3>
+
+<p>??<p>
+-->
+<H3><A name="reload">Can I reload connection info without restarting?</A>
+</H3>
+<P>Yes, you can do this. Here are the details, in a mailing list message
+ from Pluto programmer Hugh Redelmeier:</P>
+<PRE>| How can I reload config's without restarting all of pluto and klips?  I am using
+| FreeSWAN -&gt; PGPNet in a medium sized production environment, and would like to be
+| able to add new connections ( i am using include config/* ) without dropping current
+| SA's.
+| 
+| Can this be done?
+| 
+| If not, are there plans to add this kind of feature?
+
+        ipsec auto --add whatever
+This will look in the usual place (/etc/ipsec.conf) for a conn named
+whatever and add it.
+
+If you added new secrets, you need to do
+        ipsec auto --rereadsecrets
+before Pluto needs to know those secrets.
+
+| I have looked (perhaps not thoroughly enough tho) to see how to do this:
+
+There may be more bits to look for, depending on what you are trying
+to do.</PRE>
+<P>Another useful command here is<VAR> ipsec auto --replace &lt;conn_name&gt;</VAR>
+ which re-reads data for a named connection.</P>
+<H3><A name="masq.faq">Can I use several masqueraded subnets?</A></H3>
+<P>Yes. This is done all the time. See the discussion in our<A href="config.html#route_or_not">
+ setup</A> document. The only restriction is that the subnets on the two
+ ends must not overlap. See the next question.</P>
+<P>Here is a mailing list message on the topic. The user incorrectly
+ thinks you need a 2.4 kernel for this -- actually various people have
+ been doing it on 2.0 and 2.2 for quite some time -- but he has it right
+ for 2.4.</P>
+<PRE>Subject: Double NAT and freeswan working :)
+   Date: Sun, 11 Mar 2001
+   From: Paul Wouters &lt;paul@xtdnet.nl&gt;
+
+Just to share my pleasure, and make an entry for people who are searching
+the net on how to do this. Here's the very simple solution to have a double
+NAT'ed network working with freeswan. (Not sure if this is old news, but I'm
+not on the list (too much spam) and I didn't read this in any HOWTO/FAQ/doc
+on the freeswan site yet (Sandy, put it in! :)
+
+10.0.0.0/24 --- 10.0.0.1 a.b.c.d  ---- a.b.c.e {internet} ----+
+                                                              |
+10.0.1.0/24 --- 10.0.1.1 f.g.h.i  ---- f.g.h.j {internet} ----+
+
+the goal is to have the first network do a VPN to the second one, yet also
+have NAT in place for connections not destinated for the other side of the
+NAT. Here the two Linux security gateways have one real IP number (cable
+modem, dialup, whatever.
+
+The problem with NAT is you don't want packets from 10.*.*.* to 10.*.*.*
+to be NAT'ed. While with Linux 2.2, you can't, with Linux 2.4 you can.
+
+(This has been tested and works for 2.4.2 with Freeswan snapshot2001mar8b)
+
+relevant parts of /etc/ipsec.conf:
+
+        left=f.g.h.i
+        leftsubnet=10.0.1.0/24
+        leftnexthop=f.g.h.j
+        leftfirewall=yes
+        leftid=@firewall.netone.nl
+        leftrsasigkey=0x0........
+        right=a.b.c.d
+        rightsubnet=10.0.0.0/24
+        rightnexthop=a.b.c.e
+        rightfirewall=yes
+        rightid=@firewall.nettwo.nl
+        rightrsasigkey=0x0......
+        # To authorize this connection, but not actually start it, at startup,
+        # uncomment this.
+        auto=add
+
+and now the real trick. Setup the NAT correctly on both sites:
+
+iptables -t nat -F
+iptables -t nat -A POSTROUTING -o eth0 -d \! 10.0.0.0/8 -j MASQUERADE
+
+This tells the NAT code to only do NAT for packets with destination other then
+10.* networks. note the backslash to mask the exclamation mark to protect it
+against the shell.
+
+Happy painting :)
+
+Paul</PRE>
+<H3><A name="dup_route">Can I use subnets masqueraded to the same
+ addresses?</A></H3>
+<P><STRONG>No.</STRONG> The notion that IP addresses are unique is one
+ of the fundamental principles of the IP protocol. Messing with it is
+ exceedingly perilous.</P>
+<P>Fairly often a situation comes up where a company has several
+ branches, all using the same<A href="glossary.html#non-routable">
+ non-routable addresses</A>, perhaps 192.168.0.0/24. This works fine as
+ long as those nets are kept distinct. The<A href="glossary.html#masq">
+ IP masquerading</A> on their firewalls ensures that packets reaching
+ the Internet carry the firewall address, not the private address.</P>
+<P>This can break down when IPsec enters the picture. FreeS/WAN builds a
+ tunnel that pokes through both masquerades and delivers packets from<VAR>
+ leftsubnet</VAR> to<VAR> rightsubnet</VAR> and vice versa. For this to
+ work, the two subnets<EM> must</EM> be distinct.</P>
+<P>There are several solutions to this problem.</P>
+<P>Usually, you<STRONG> re-number the subnets</STRONG>. Perhaps the
+ Vancouver office becomes 192.168.101.0/24, Calgary 192.168.102.0/24 and
+ so on. FreeS/WAN can happily handle this. With, for example<VAR>
+ leftsubnet=192.168.101.0/24</VAR> and<VAR> rightsubnet=192.168.102.0/24</VAR>
+ in a connection description, any machine in Calgary can talk to any
+ machine in Vancouver. If you want to be more restrictive and use
+ something like<VAR> leftsubnet=192.168.101.128/25</VAR> and<VAR>
+ rightsubnet=192.168.102.240/28</VAR> so only certain machines on each
+ end have access to the tunnel, that's fine too.</P>
+<P>You could also<STRONG> split the subnet</STRONG> into smaller ones,
+ for example using<VAR> 192.168.1.0/25</VAR> in Vancouver and<VAR>
+ rightsubnet=192.168.0.128/25</VAR> in Calgary.</P>
+<P>Alternately, you can just<STRONG> give up routing</STRONG> directly
+ to machines on the subnets. Omit the<VAR> leftsubnet</VAR> and<VAR>
+ rightsubnet</VAR> parameters from your connection descriptions. Your
+ IPsec tunnels will then run between the public interfaces of the two
+ firewalls. Packets will be masqueraded both before they are put into
+ tunnels and after they emerge. Your Vancouver client machines will see
+ only one Calgary machine, the firewall.</P>
+<H3><A name="road.masq">Can I assign a road warrior an address on my net
+ (a virtual identity)?</A></H3>
+<P>Often it would be convenient to be able to give a Road Warrior an IP
+ address which appears to be on the local network. Some IPsec
+ implementations have support for this, sometimes calling the feature
+ &quot;virtual identity&quot;.</P>
+<P>Currently (Sept 2002) FreeS/WAN does not support this, and we have no
+ definite plans to add it. The difficulty is that is not yet a standard
+ mechanism for it. There is an Internet Draft for a method of doing it
+ using<A href="glossary.html#DHCP"> DHCP</A> which looks promising.
+ FreeS/WAN may support that in a future release.</P>
+<P>In the meanwhile, you can do it yourself using the Linux iproute2(8)
+ facilities. Details are in<A href="http://www.av8n.com/vpn/iproute2.htm">
+ this paper</A>.</P>
+<P>Another method has also been discussed on the mailing list.:</P>
+<UL>
+<LI>You can use a variant of the<A href="adv_config.html#extruded.config">
+ extruded subnet</A> procedure.</LI>
+<LI>You have to avoid having the road warrior's assigned address within
+ the range you actually use at home base. See previous question.</LI>
+<LI>On the other hand, you want the roadwarrior's address to be within
+ the range that<EM> seems</EM> to be on your network.</LI>
+</UL>
+<P>For example, you might have:</P>
+<DL>
+<DT>leftsubnet=a.b.c.0/25</DT>
+<DD>head office network</DD>
+<DT>rightsubnet=a.b.c.129/32</DT>
+<DD>extruded to a road warrior. Note that this is not in a.b.c.0/25</DD>
+<DT>a.b.c.0/24</DT>
+<DD>whole network, including both the above</DD>
+</DL>
+<P>You then set up routing so that the office machines use the IPsec
+ gateway as their route to a.b.c.128/25. The leftsubnet parameter tells
+ the road warriors to use tunnels to reach a.b.c.0/25, so you should
+ have two-way communication. Depending or your network and applications,
+ there may be some additional work to do on DNS or Windows configuration</P>
+<H3><A name="road.many">Can I support many road warriors with one
+ gateway?</A></H3>
+<P>Yes. This is easily done, using</P>
+<DL>
+<DT>either RSA authentication</DT>
+<DD>standard in the FreeS/WAN distribution</DD>
+<DT>or X.509 certificates</DT>
+<DD>requires<A href="#PKIcert"> Super FreeS/WAN or a patch</A>.</DD>
+</DL>
+<P>In either case, each Road Warrior must have a different key or
+ certificate.</P>
+<P>It is also possible using pre-shared key authentication, though we
+ don't recommend this; see the<A href="#road.PSK"> next question</A> for
+ details.</P>
+<P>If you expect to have more than a few dozen Road Warriors connecting
+ simultaneously, you may need a fairly powerful gateway machine. See our
+ document on<A href="performance.html"> FreeS/WAN performance</A>.</P>
+<H3><A name="road.PSK">Can I have many road warriors using shared secret
+ authentication?</A></H3>
+<P><STRONG>Yes, but avoid it if possible</STRONG>.</P>
+<P>You can have multiple Road Warriors using shared secret
+ authentication<STRONG> only if they all use the same secret</STRONG>.
+ You must also set:</P>
+<P></P>
+<PRE>   uniqueids=no   </PRE>
+<P>in the connection definition.</P>
+<P>Why it's less secure:</P>
+<UL>
+<LI>If you have many users, it becomes almost certain the secret will
+ leak</LI>
+<LI>The secret becomes quite valuable to an attacker</LI>
+<LI>All users authenticate the same way, so the gateway cannot tell them
+ apart for logging or access control purposes</LI>
+<LI>Changing the secret is difficult. You have to securely notify all
+ users.</LI>
+<LI>If you find out the secret has been compromised, you can change it,
+ but then what? None of your users can connect without the new secret.
+ How will you notify them all, quickly and securely, without using the
+ VPN?</LI>
+</UL>
+<P>This is a designed-in limitation of the<A href="glossary.html#IKE">
+ IKE</A> key negotiation protocol, not a problem with our
+ implementation.</P>
+<P><STRONG>We very strongly recommend that you avoid using shared secret
+ authentication for multiple Road Warriors.</STRONG> Use RSA
+ authentication instead.</P>
+<P>The longer story: When using shared secrets, the protocol requires
+ that the responding gateway be able to determine which secret to use at
+ a time when all it knows about the initiator is an IP address. This
+ works fine if you know the initiator's address in advance and can use
+ it to look up the appropiriate secret. However, it fails for Road
+ Warriors since the gateway cannot know their IP addresses in advance.</P>
+<P>With RSA signatures (or certificates) the protocol is slightly
+ different. The initiator provides an identifier early in the exchange
+ and the responder can use that identifier to look up the correct key or
+ certificate. See<A href="#road.many"> above</A>.</P>
+<H3><A name="QoS">Can I use Quality of Service routing with FreeS/WAN?</A>
+</H3>
+<P>From project technical lead Henry Spencer:</P>
+<PRE>&gt; Do QoS add to FreeS/WAN?
+&gt; For example integrating DiffServ and FreeS/WAN?
+
+With a current version of FreeS/WAN, you will have to add hidetos=no to
+the config-setup section of your configuration file.  By default, the TOS
+field of tunnel packets is zeroed; with hidetos=no, it is copied from the
+packet inside.  (This is a modest security hole, which is why it is no
+longer the default.)
+
+DiffServ does not interact well with tunneling in general.  Ways of
+improving this are being studied.</PRE>
+<P>Copying the<A href="glossary.html#TOS"> TOS</A> (type of service)
+ information from the encapsulated packet to the outer header reveals
+ the TOS information to an eavesdropper. This does not tell him much,
+ but it might be of use in<A href="glossary.html#traffic"> traffic
+ analysis</A>. Since we do not have to give it to him, our default is
+ not to.</P>
+<P>Even with the TOS hidden, you can still:</P>
+<UL>
+<LI>apply QOS rules to the tunneled (ESP) packets; for example, by
+ giving ESP packets a certain priority.</LI>
+<LI>apply QOS rules to the packets as they enter or exit the tunnel via
+ an IPsec virtual interface (eg.<VAR> ipsec0</VAR>).</LI>
+</UL>
+<P>See<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf(5)</A> for more
+ on the<VAR> hidetos=</VAR> parameter.</P>
+<H3><A name="deadtunnel">Can I recognise dead tunnels and shut them
+ down?</A></H3>
+<P>There is no general mechanism to do this is in the IPsec protocols.</P>
+<P>From time to time, there is discussion on the IETF Working Group<A href="mail.html#ietf">
+ mailing list</A> of adding a &quot;keep-alive&quot; mechanism (which some say
+ should be called &quot;make-dead&quot;), but it is a fairly complex problem and
+ no consensus has been reached on whether or how it should be done.</P>
+<P>The protocol does have optional<A href="#ignore"> delete-SA</A>
+ messages which one side can send when it closes a connection in hopes
+ this will cause the other side to do the same. FreeS/WAN does not
+ currently support these. In any case, they would not solve the problem
+ since:</P>
+<UL>
+<LI>a gateway that crashes or hangs would not send the messages</LI>
+<LI>the sender is not required to send them</LI>
+<LI>they are not authenticated, so any receiver that trusts them leaves
+ itself open to a<A href="glossary.html#DOS"> denial of service</A>
+ attack</LI>
+<LI>the receiver is not required to do anything about them</LI>
+<LI>the receiver cannot acknowledge them; the protocol provides no
+ mechanism for that</LI>
+<LI>since they are not acknowledged, the sender cannot rely on them</LI>
+</UL>
+<P>However, connections do have limited lifetimes and you can control
+ how many attempts your gateway makes to rekey before giving up. For
+ example, you can set:</P>
+<PRE>conn default
+        keyingtries=3
+        keylife=30m</PRE>
+<P>With these settings old connections will be cleaned up. Within 30
+ minutes of the other end dying, rekeying will be attempted. If it
+ succeeds, the new connection replaces the old one. If it fails, no new
+ connection is created. Either way, the old connection is taken down
+ when its lifetime expires.</P>
+<P>Here is a mailing list message on the topic from FreeS/WAN tech
+ support person Claudia Schmeing:</P>
+<PRE>You ask how to determine whether a tunnel is redundant:
+
+&gt; Can anybody explain the best way to determine this. Esp when a RW has
+&gt; disconnected? I thought 'ipsec auto --status' might be one way.
+
+If a tunnel goes down from one end, Linux FreeS/WAN on the
+other end has no way of knowing this until it attempts to rekey.
+Once it tries to rekey and fails, it will 'know' that the tunnel is 
+down.
+
+Because it doesn't have a way of knowing the state until this point, 
+it will also not be able to tell you the state via ipsec auto --status.
+
+&gt; However, comparing output from a working tunnel with that of one that
+&gt; was closed 
+&gt; did not show clearly show tunnel status.
+
+If your tunnel is down but not 'unrouted' (see man ipsec_auto), you
+should not be able to ping the opposite side of the tunnel. You can
+use this as an indicator of tunnel status.
+
+On a related note, you may be interested to know that as of 1.7, 
+redundant tunnels caused by RW disconnections are likely to be 
+less of a pain. From doc/CHANGES:
+
+    There is a new configuration parameter, uniqueids, to control a new Pluto
+    option:  when a new connection is negotiated with the same ID as an old
+    one, the old one is deleted immediately.  This should help eliminate
+    dangling Road Warrior connections when the same Road Warrior reconnects. 
+    It thus requires that IDs not be shared by hosts (a previously legal but
+    probably useless capability).  NOTE WELL:  the sample ipsec.conf now has
+    uniqueids=yes in its config-setup section.
+
+
+Cheers,
+
+Claudia</PRE>
+<H3><A name="demanddial">Can I build IPsec tunnels over a demand-dialed
+ link?</A></H3>
+<P>This is possible, but not easy. FreeS/WAN technical lead Henry
+ Spencer wrote:</P>
+<PRE>&gt; 5. If the ISDN link goes down in between and is reestablished, the SAs
+&gt; are still up but the eroute are deleted and the IPsec interface shows
+&gt; garbage (with ifconfig)
+&gt; 6. Only restarting IPsec will bring the VPN back online.
+
+This one is awkward to solve.  If the real interface that the IPsec
+interface is mounted on goes down, it takes most of the IPsec machinery
+down with it, and a restart is the only good way to recover. 
+
+The only really clean fix, right now, is to split the machines in two: 
+
+1. A minimal machine serves as the network router, and only it is aware
+that the link goes up and down. 
+
+2. The IPsec is done on a separate gateway machine, which thinks it has
+a permanent network connection, via the router.
+
+This is clumsy but it does work.  Trying to do both functions within a
+single machine is tricky.  There is a software package (diald) which will
+give the illusion of a permanent connection for demand-dialed modem
+connections; I don't know whether it's usable for ISDN, or whether it can
+be made to cooperate properly with FreeS/WAN. 
+
+Doing a restart each time the interface comes up *does* work, although it
+is a bit painful.  I did that with PPP when I was running on a modem link;
+it wasn't hard to arrange the PPP scripts to bring IPsec up and down at
+the right times.  (I'd meant to investigate diald but never found time.)
+
+In principle you don't need to do a complete restart on reconnect, but you
+do have to rebuild some things, and we have no nice clean way of doing
+only the necessary parts.</PRE>
+<P>In the same thread, one user commented:</P>
+<PRE>Subject: Re: linux-ipsec: IPsec and Dial Up Connections
+   Date: Wed, 22 Nov 2000
+   From: Andy Bradford &lt;andyb@calderasystems.com&gt;
+
+On Wed, 22 Nov 2000 19:47:11 +0100, Philip Reetz wrote:
+
+&gt; Are there any ideas what might be the cause of the problem and any way
+&gt; to work around it.
+&gt; Any help is highly appreciated.
+
+On my laptop, when using ppp there is a ip-up script in /etc/ppp that 
+will be executed each time that the ppp interface is brought up.  
+Likewise there is an ip-down script that is called when it is taken 
+down.  You might consider custimzing those to stop and start FreeS/WAN 
+with each connection.  I believe that ISDN uses the same files, though 
+I could be wrong---there should be something similar though.</PRE>
+<H3><A name="GRE">Can I build GRE, L2TP or PPTP tunnels over IPsec?</A></H3>
+<P>Yes. Normally this is not necessary, but it is useful in a few
+ special cases. For example, if you must route non-IP packets such as
+ IPX, you will need to use a tunneling protocol that can route these
+ packets. IPsec can be layered around it for extra security. Another
+ example: you can provide failover protection for high availability (HA)
+ environments by combining IPsec with other tools. Ken Bantoft describes
+ one such setup in<A HREF="http://www.freeswan.ca/docs/HA"> Using
+ FreeS/WAN with Linux-HA, GRE, OSPF and BGP for enterprise grade VPN
+ solutions</A>.</P>
+<P>GRE over IPsec is covered as part of<A HREF="http://www.freeswan.ca/docs/HA">
+ that document</A>.<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/07/msg00209.html">
+ Here are links</A> to other GRE resources. Jacco de Leuw has created<A HREF="http://www.jacco2.dds.nl/networking/">
+ this page on L2TP over IPsec</A> with instructions for FreeS/WAN and
+ several other brands of IPsec software.</P>
+<P>Please let us know of other useful links via the<A HREF="mail.html">
+ mailing lists</A>.</P>
+<H3><A name="NetBIOS">... use Network Neighborhood (Samba, NetBIOS) over
+ IPsec?</A></H3>
+<P>Your local PC needs to know how to translate NetBIOS names to IP
+ addresses. It may do this either via a local LMHOSTS file, or using a
+ local or remote WINS server. The WINS server is preferable since it
+ provides a centralized source of the information to the entire network.
+ To use a WINS server over the<A HREF="glossary.html#VPN"> VPN</A> (or
+ any IP-based network), you must enable &quot;NetBIOS over TCP&quot;.</P>
+<P><A HREF="http://www.samba.org">Samba</A> can emulate a WINS server on
+ Linux.</P>
+<P> See also several discussions in our<A HREF="http://lists.freeswan.org/pipermail/users/2002-September/thread.html">
+ September 2002 Users archives</A></P>
+<H2><A name="setup.faq">Life's little mysteries</A></H2>
+<P>FreeS/WAN is a fairly complex product. (Neither the networks it runs
+ on nor the protocols it uses are simple, so it could hardly be
+ otherwise.) It therefore sometimes exhibits behaviour which can be
+ somewhat confusing, or has problems which are not easy to diagnose.
+ This section tries to explain those problems.</P>
+<P>Setup and configuration of FreeS/WAN are covered in other
+ documentation sections:</P>
+<UL>
+<LI><A href="quickstart.html">basic setup and configuration</A></LI>
+<LI><A href="adv_config.html">advanced configuration</A></LI>
+<LI><A href="trouble.html">Troubleshooting</A></LI>
+</UL>
+<P>However, we also list some of the commonest problems here.</P>
+<H3><A name="cantping">I cannot ping ....</A></H3>
+<P>This question is dealt with in the advanced configuration section
+ under the heading<A href="adv_config.html#multitunnel"> multiple
+ tunnels</A>.</P>
+<P>The standard subnet-to-subnet tunnel protects traffic<STRONG> only
+ between the subnets</STRONG>. To test it, you must use pings that go
+ from one subnet to the other.</P>
+<P>For example, suppose you have:</P>
+<PRE>      subnet a.b.c.0/24
+             |
+      eth1 = a.b.c.1
+         gate1
+      eth0 = 192.0.2.8
+             |
+
+       ~ internet ~
+
+             |
+      eth0 = 192.0.2.11
+         gate2
+      eth1 = x.y.z.1
+              |
+       subnet x.y.z.0/24</PRE>
+<P>and the connection description:</P>
+<PRE>conn abc-xyz
+     left=192.0.2.8
+     leftsubnet=a.b.c.0/24
+     right=192.0.2.11
+     rightsubnet=x.y.z.0/24</PRE>
+<P>You can test this connection description only by sending a ping that
+ will actually go through the tunnel. Assuming you have machines at
+ addresses a.b.c.2 and x.y.z.2, pings you might consider trying are:</P>
+<DL>
+<DT>ping from x.y.z.2 to a.b.c.2 or vice versa</DT>
+<DD>Succeeds if tunnel is working. This is the<STRONG> only valid test
+ of the tunnel</STRONG>.</DD>
+<DT>ping from gate2 to a.b.c.2 or vice versa</DT>
+<DD><STRONG>Does not use tunnel</STRONG>. gate2 is not on protected
+ subnet.</DD>
+<DT>ping from gate1 to x.y.z.2 or vice versa</DT>
+<DD><STRONG>Does not use tunnel</STRONG>. gate1 is not on protected
+ subnet.</DD>
+<DT>ping from gate1 to gate2 or vice versa</DT>
+<DD><STRONG>Does not use tunnel</STRONG>. Neither gate is on a protected
+ subnet.</DD>
+</DL>
+<P>Only the first of these is a useful test of this tunnel. The others
+ do not use the tunnel. Depending on other details of your setup and
+ routing, they:</P>
+<UL>
+<LI>either fail, telling you nothing about the tunnel</LI>
+<LI>or succeed, telling you nothing about the tunnel since these packets
+ use some other route</LI>
+</UL>
+<P>In some cases, you may be able to get around this. For the example
+ network above, you could use:</P>
+<PRE>        ping -I a.b.c.1 x.y.z.1</PRE>
+<P>Both the adresses given are within protected subnets, so this should
+ go through the tunnel.</P>
+<P>If required, you can build additional tunnels so that all the
+ machines involved can talk to all the others. See<A href="adv_config.html#multitunnel">
+ multiple tunnels</A> in the advanced configuration document for
+ details.</P>
+<H3><A name="forever">It takes forever to ...</A></H3>
+<P>Users fairly often report various problems involving long delays,
+ sometimes on tunnel setup and sometimes on operations done through the
+ tunnel, occasionally on simple things like ping or more often on more
+ complex operations like doing NFS or Samba through the tunnel.</P>
+<P>Almost always, these turn out to involve failure of a DNS lookup. The
+ timeouts waiting for DNS are typically set long so that you won't time
+ out when a query involves multiple lookups or long paths. Genuine
+ failures therefore produce long delays before they are detected.</P>
+<P>A mailing list message from project technical lead Henry Spencer:</P>
+<PRE>&gt; ... when i run /etc/rc.d/init.d/ipsec start, i get:
+&gt; ipsec_setup: Starting FreeS/WAN IPsec 1.5...
+&gt; and it just sits there, doesn't give back my bash prompt.
+
+Almost certainly, the problem is that you're using DNS names in your
+ipsec.conf, but DNS lookups are not working for some reason.  You will
+get your prompt back... eventually.  But the DNS timeouts are long.
+Doing something about this is on our list, but it is not easy.</PRE>
+<P>In the meanwhile, we recommend that connection descriptions in<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A> use numeric IP addresses rather than names which will
+ require a DNS lookup.</P>
+<P>Names that do not require a lookup are fine. For example:</P>
+<UL>
+<LI>a road warrior might use the identity<VAR>
+ rightid=@lancelot.example.org</VAR></LI>
+<LI>the gateway might use<VAR> leftid=@camelot.example.org</VAR></LI>
+</UL>
+<P>These are fine. The @ sign prevents any DNS lookup. However, do not
+ attempt to give the gateway address as<VAR> left=camelot.example.org</VAR>
+. That requires a lookup.</P>
+<P>A post from one user after solving a problem with long delays:</P>
+<PRE>Subject: Final Answer to Delay!!!
+   Date: Mon, 19 Feb 2001
+   From: &quot;Felippe Solutions&quot; &lt;felippe@solutionstecnologia.com.br&gt;
+
+Sorry people, but seems like the Delay problem had nothing to do with
+freeswan.
+
+The problem was DNS as some people sad from the beginning, but not the way
+they thought it was happening. Samba, ssh, telnet and other apps try to
+reverse lookup addresses when you use IP numbers (Stupid that ahh).
+
+I could ping very fast because I always ping with &quot;-n&quot; option, but I don't
+know the option on the other apps to stop reverse addressing so I don't use
+it.</PRE>
+<P>This post is fairly typical. These problems are often tricky and
+ frustrating to diagnose, and most turn out to be DNS-related.</P>
+<P>One suggestion for diagnosis: test with both names and addresses if
+ possible. For example, try all of:</P>
+<UL>
+<LI>ping<VAR> address</VAR></LI>
+<LI>ping -n<VAR> address</VAR></LI>
+<LI>ping<VAR> name</VAR></LI>
+</UL>
+<P>If these behave differently, the problem must be DNS-related since
+ the three commands do exactly the same thing except for DNS lookups.</P>
+<H3><A name="route">I send packets to the tunnel with route(8) but they
+ vanish</A></H3>
+<P>IPsec connections are designed to carry only packets travelling
+ between pre-defined connection endpoints. As project technical lead
+ Henry Spencer put it:</P>
+<BLOCKQUOTE> IPsec tunnels are not just virtual wires; they are virtual
+ wires with built-in access controls. Negotiation of an IPsec tunnel
+ includes negotiation of access rights for it, which don't include
+ packets to/from other IP addresses. (The protocols themselves are quite
+ inflexible about this, so there are limits to what we can do about it.)</BLOCKQUOTE>
+<P>For fairly obvious security reasons, and to comply with the IPsec
+ RFCs,<A href="glossary.html#KLIPS"> KLIPS</A> drops any packets it
+ receives that are not allowed on the tunnels currently defined. So if
+ you send it packets with<VAR> route(8)</VAR>, and suitable tunnels are
+ not defined, the packets vanish. Whether this is reported in the logs
+ depends on the setting of<VAR> klipsdebug</VAR> in your<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A> file.</P>
+<P>To rescue vanishing packets, you must ensure that suitable tunnels
+ for them exist, by editing the connection descriptions in<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A>. For example, supposing you have a simple setup:</P>
+<PRE>         leftsubnet -- leftgateway === internet === roadwarrior</PRE>
+<P>If you want to give the roadwarrior access to some resource that is
+ located behind the left gateway but is not in the currently defined
+ left subnet, then the usual procedure is to define an additional tunnel
+ for those packets by creating a new connection description.</P>
+<P>In some cases, it may be easier to alter an existing connection
+ description, enlarging the definition of<VAR> leftsubnet</VAR>. For
+ example, instead of two connection descriptions with 192.168.8.0/24 and
+ 192.168.9.0/24 as their<VAR> leftsubnet</VAR> parameters, you can use a
+ single description with 192.168.8.0/23.</P>
+<P>If you have multiple endpoints on each side, you need to ensure that
+ there is a route for each pair of endpoints. See this<A href="adv_config.html#multitunnel">
+ example</A>.</P>
+<H3><A name="down_route">When a tunnel goes down, packets vanish</A></H3>
+<P>This is a special case of the vanishing packet problem described in
+ the previous question. Whenever KLIPS sees packets for which it does
+ not have a tunnel, it drops them.</P>
+<P>When a tunnel goes away, either because negotiations with the other
+ gateway failed or because you gave an<VAR> ipsec auto --down</VAR>
+ command, the route to its other end is left pointing into KLIPS, and
+ KLIPS will drop packets it has no tunnel for.</P>
+<P>This is a documented design decision, not a bug. FreeS/WAN must not
+ automatically adjust things to send packets via another route. The
+ other route might be insecure.</P>
+<P>Of course, re-routing may be necessary in many cases. In those cases,
+ you have to do it manually or via scripts. We provide the<VAR> ipsec
+ auto --unroute</VAR> command for these cases.</P>
+<P>From<A href="manpage.d/ipsec_auto.8.html"> ipsec_auto(8)</A>:</P>
+<BLOCKQUOTE> Normally, pluto establishes a route to the destination
+ specified for a connection as part of the --up operation. However, the
+ route and only the route can be established with the --route operation.
+ Until and unless an actual connection is established, this discards any
+ packets sent there, which may be preferable to having them sent
+ elsewhere based on a more general route (e.g., a default route).</BLOCKQUOTE><BLOCKQUOTE>
+ Normally, pluto's route to a destination remains in place when a --down
+ operation is used to take the connection down (or if connection setup,
+ or later automatic rekeying, fails). This permits establishing a new
+ connection (perhaps using a different specification; the route is
+ altered as necessary) without having a ``window'' in which packets
+ might go elsewhere based on a more general route. Such a route can be
+ removed using the --unroute operation (and is implicitly removed by
+ --delete).</BLOCKQUOTE>
+<P>See also this mailing list<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/11/msg00523.html">
+ message</A>.</P>
+<H3><A name="firewall_ate">The firewall ate my packets!</A></H3>
+<P>If firewalls filter out:</P>
+<UL>
+<LI>either the UDP port 500 packets used in IKE negotiations</LI>
+<LI>or the ESP and AH (protocols 50 and 51) packets used to implement
+ the IPsec tunnel</LI>
+</UL>
+<P>then IPsec cannot work. The first thing to check if packets seem to
+ be vanishing is the firewall rules on the two gateway machines and any
+ other machines along the path that you have access to.</P>
+<P>For details, see our document on<A href="firewall.html"> firewalls</A>
+.</P>
+<P>Some advice from technical lead Henry Spencer on diagnosing such
+ problems:</P>
+<PRE>&gt; &gt; Packets vanishing between the hardware interface and the ipsecN interface
+&gt; &gt; is usually the result of firewalls not being configured to let them in...
+&gt; 
+&gt; Thanks for the suggestion. If only it were that simple! My ipchains startup
+&gt; script does take care of that, but just in case I manually inserted rules 
+&gt; accepting everything from london on dublin. No difference.
+
+The other thing to check is whether the &quot;RX packets dropped&quot; count on the
+ipsecN interface (run &quot;ifconfig ipsecN&quot;, for N=1 or whatever, to see the
+counts) is rising.  If so, then there's some sort of configuration mismatch
+between the two ends, and IPsec itself is rejecting them.  If none of the
+ipsecN counts is rising, then the packets are never reaching the IPsec
+machinery, and the problem is almost certainly in firewalls etc.</PRE>
+<H3><A name="dropconn">Dropped connections</A></H3>
+<P>Networks being what they are, IPsec connections can be broken for any
+ number of reasons, ranging from hardware failures to various software
+ problems such as the path MTU problems discussed<A href="#pmtu.broken">
+ elsewhere in the FAQ</A>. Fortunately, various diagnostic tools exist
+ that help you sort out many of the possible problems.</P>
+<P>There is one situation, however, where FreeS/WAN (using default
+ settings) may destroy a connection for no readily apparent reason. This
+ occurs when things are<STRONG> misconfigured</STRONG> so that<STRONG>
+ two tunnels</STRONG> from the same gateway expect<STRONG> the same
+ subnet on the far end</STRONG>.</P>
+<P>In this situation, the first tunnel comes up fine and works until the
+ second is established. At that point, because of the way we track
+ connections internally, the first tunnel ceases to exist as far as this
+ gateway is concerned. Of course the far end does not know that, and a
+ storm of error messages appears on both systems as it tries to use the
+ tunnel.</P>
+<P>If the far end gives up, goes back to square one and negotiates a new
+ tunnel, then that wipes out the second tunnel and ...</P>
+<P>The solution is simple.<STRONG> Do not build multiple conn
+ descriptions with the same remote subnet</STRONG>.</P>
+<P>This is actually intended to be a feature, rather than a bug.
+ Consider the situation where a single remote system goes down, then
+ comes back up and reconnects to the gateway. It is useful to have the
+ gateway tear down the old tunnel and recover resources when the
+ reconnection is made. It recognises that situation by checking the
+ remote subnet for each tunnel it builds and discarding duplicates. This
+ works fine as long as you don't configure multiple tunnels with the
+ same remote subnet.</P>
+<P>If this behaviour is inconvenient for you, you can disable it by
+ setting<VAR> uniqueids=no</VAR> in<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A>.</P>
+<H3><A name="defaultroutegone">Disappearing %defaultroute</A></H3>
+<P>When an underlying connection (eg. ppp) goes down, FreeS/WAN will not
+ recover properly without a little help. Here are the symptoms that
+ FreeS/WAN user Michael Carmody noticed:</P>
+<PRE>
+&gt; After about 24 hours the freeswan connection takes over the default route.
+&gt; 
+&gt; i.e instead of deafult gateway pointing to the router via eth0, it becomes a 
+&gt; pointer to the router via ipsec0.
+ 
+&gt; All internet access is then lost as all replies (and not just the link I 
+&gt; wanted) are routed out ipsec0 and the router doesn't respond to the ipsec 
+&gt; traffic.
+</PRE>
+<P>If you're using a FreeS/WAN 2.x/KLIPS system, simply re-attach the
+ IPsec virtual interface with<EM> ipsec tnconfig</EM> command such as:</P>
+<PRE>    ipsec tnconfig --attach --virtual ipsec0 --physical ppp0</PRE>
+<P>In your command, name the physical and virtual interfaces as they
+ appear paired on your system during regular uptime. For a system with
+ several physical/virtual interface pairs on flaky links, you'll need
+ more than one such command. If you're using FreeS/WAN 1.x, you must
+ restart FreeS/WAN, which is more time consuming.</P>
+<P><A href="http://lists.freeswan.org/pipermail/design/2002-July/003070.html">
+ Here</A> is a script which can help to automate the process of
+ FreeS/WAN restart at need. It could easily be adapted to use tnconfig
+ instead.</P>
+<H3><A name="tcpdump.faq">TCPdump on the gateway shows strange things</A>
+</H3>
+ As another user pointed out, keeping the connect
+<P>Attempting to look at IPsec packets by running monitoring tools on
+ the IPsec gateway machine can produce silly results. That machine is
+ mangling the packets for IPsec, and possibly for firewall or NAT
+ purposes as well. If the internals of the machine's IP stack are not
+ what the monitoring tool expects, then the tool can misinterpret them
+ and produce nonsense output.</P>
+<P>See our<A href="testing.html#tcpdump.test"> testing</A> document for
+ more detail.</P>
+<H3><A name="no_trace">Traceroute does not show anything between the
+ gateways</A></H3>
+<P>As far as traceroute can see, the two gateways are one hop apart; the
+ data packet goes directly from one to the other through the tunnel. Of
+ course the outer packets that implement the tunnel pass through
+ whatever lies between the gateways, but those packets are built and
+ dismantled by the gateways. Traceroute does not see them and cannot
+ report anything about their path.</P>
+<P>Here is a mailing list message with more detail.</P>
+<PRE>Date: Mon, 14 May 2001
+To: linux-ipsec@freeswan.org
+From: &quot;John S. Denker&quot; &lt;jsd@research.att.com&lt;
+Subject: Re: traceroute: one virtual hop
+
+At 02:20 PM 5/14/01 -0400, Claudia Schmeing wrote:
+&gt;
+&gt;&gt; &gt; A bonus question: traceroute in subnet to subnet enviroment looks like:
+&gt;&gt; &gt; 
+&gt;&gt; &gt; traceroute to andris.dmz (172.20.24.10), 30 hops max, 38 byte packets
+&gt;&gt; &gt; 1  drama (172.20.1.1)  0.716 ms  0.942 ms  0.434 ms
+&gt;&gt; &gt; 2  * * *
+&gt;&gt; &gt; 3  andris.dmz (172.20.24.10)  73.576 ms  78.858 ms  79.434 ms
+&gt;&gt; &gt; 
+&gt;&gt; &gt; Why aren't there the other hosts which take part in the delivery during 
+&gt;    * * * ?
+&gt;
+&gt;If there is an ipsec tunnel between GateA and Gate B, this tunnel forms a 
+&gt;'virtual wire'.  When it is tunneled, the original packet becomes an inner 
+&gt;packet, and new ESP and/or AH headers are added to create an outer packet 
+&gt;around it. You can see an example of how this is done for AH at 
+&gt;doc/ipsec.html#AH . For ESP it is similar.
+&gt;
+&gt;Think about the packet's path from the inner packet's perspective.
+&gt;It leaves the subnet, goes into the tunnel, and re-emerges in the second
+&gt;subnet. This perspective is also the only one available to the
+&gt;'traceroute' command when the IPSec tunnel is up.
+
+Claudia got this exactly right.  Let me just expand on a couple of points:
+
+*) GateB is exactly one (virtual) hop away from GateA.  This is how it
+would be if there were a physically private wire from A to B.  The
+virtually private connection should work the same, and it does.
+
+*) While the information is in transit from GateA to GateB, the hop count
+of the outer header (the &quot;envelope&quot;) is being decremented.  The hop count
+of the inner header (the &quot;contents&quot; of the envelope) is not decremented and
+should not be decremented.  The hop count of the outer header is not
+derived from and should not be derived from the hop count of the inner header.
+
+Indeed, even if the packets did time out in transit along the tunnel, there
+would be no way for traceroute to find out what happened.  Just as
+information cannot leak _out_ of the tunnel to the outside, information
+cannot leak _into_ the tunnel from outside, and this includes ICMP messages
+from routers along the path.
+
+There are some cases where one might wish for information about what is
+happening at the IP layer (below the tunnel layer) -- but the protocol
+makes no provision for this.  This raises all sorts of conceptual issues.
+AFAIK nobody has ever cared enough to really figure out what _should_
+happen, let alone implement it and standardize it.
+
+*) I consider the &quot;* * *&quot; to be a slight bug.  One might wish for it to be
+replaced by &quot;GateB GateB GateB&quot;.  It has to do with treating host-to-subnet
+traffic different from subnet-to-subnet traffic (and other gory details).
+I fervently hope KLIPS2 will make this problem go away.
+
+*) If you want to ask questions about the link from GateA to GateB at the
+IP level (below the tunnel level), you have to ssh to GateA and launch a
+traceroute from there.</PRE>
+<H2><A name="man4debug">Testing in stages</A></H2>
+<P>It is often useful in debugging to test things one at a time:</P>
+<UL>
+<LI>disable IPsec entirely, for example by turning it off with
+ chkconfig(8), and make sure routing works</LI>
+<LI>Once that works, try a manually keyed connection. This does not
+ require key negotiation between Pluto and the key daemon on the other
+ end.</LI>
+<LI>Once that works, try automatically keyed connections</LI>
+<LI>Once IPsec works, add packet compression</LI>
+<LI>Once everything seems to work, try stress tests with large
+ transfers, many connections, frequent re-keying, ...</LI>
+</UL>
+<P>FreeS/WAN releases are tested for all of these, so you can be
+ reasonably certain they<EM> can</EM> do them all. Of course, that does
+ not mean they<EM> will</EM> on the first try, especially if you have
+ some unusual configuration.</P>
+<P>The rest of this section gives information on diagnosing the problem
+ when each of the above steps fails.</P>
+<H3><A name="nomanual">Manually keyed connections don't work</A></H3>
+<P>Suspect one of:</P>
+<UL>
+<LI>mis-configuration of IPsec system in the /etc/ipsec.conf file
+<BR> common errors are incorrect interface or next hop information</LI>
+<LI>mis-configuration of manual connection in the /etc/ipsec.conf file</LI>
+<LI>routing problems causing IPsec packets to be lost</LI>
+<LI>bugs in KLIPS</LI>
+<LI>mismatch between the transforms we support and those another IPsec
+ implementation offers.</LI>
+</UL>
+<H3><A name="spi_error">One manual connection works, but second one
+ fails</A></H3>
+<P>This is a fairly common problem when attempting to configure multiple
+ manually keyed connections from a single gateway.</P>
+<P>Each connection must be identified by a unique<A href="glossary.html#SPI">
+ SPI</A> value. For automatic connections, these values are assigned
+ automatically. For manual connections, you must set them with<VAR> spi=</VAR>
+ statements in<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf(5)</A>.</P>
+<P>Each manual connection must have a unique SPI value in the range
+ 0x100 to 0x999. Two or more with the same value will fail. For details,
+ see our doc section<A href="adv_config.html#prodman"> Using manual
+ keying in production</A> and the man page<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A>.</P>
+<H3><A name="man_no_auto">Manual connections work, but automatic keying
+ doesn't</A></H3>
+<P>The most common reason for this behaviour is a firewall dropping the
+ UDP port 500 packets used in key negotiation.</P>
+<P>Other possibilities:</P>
+<UL>
+<LI>mis-configuration of auto connection in the /etc/ipsec.conf file.
+<P>One common configuration error is forgetting that you need<VAR>
+ auto=add</VAR> to load the connection description on the receiving end
+ so it recognises the connection when the other end asks for it.</P>
+</LI>
+<LI>error in shared secret in /etc/ipsec.secrets</LI>
+<LI>one gateway lacks a route to the other so Pluto's UDP packets are
+ lost</LI>
+<LI>bugs in Pluto</LI>
+<LI>incompatibilities between Pluto's<A href="glossary.html#IKE"> IKE</A>
+ implementation and the IKE at the other end of the tunnel.
+<P>Some possibile problems are discussed in out<A href="interop.html#interop.problem">
+ interoperation</A> document.</P>
+</LI>
+</UL>
+<H3><A name="nocomp">IPsec works, but connections using compression fail</A>
+</H3>
+<P>When we first added compression, we saw some problems:</P>
+<UL>
+<LI>compatibility issues with other implementations. We followed the
+ RFCs and omitted some extra material that many compression libraries
+ add by default. Some other implementations left the extras in</LI>
+<LI>bugs in assembler compression routines on non-Intel CPUs. The
+ workaround is to use C code instead of possibly problematic assembler.</LI>
+</UL>
+<P>We have not seen either problem in some time (at least six months as
+ I write in March 2002), but if you have some unusual configuration then
+ you may see them.</P>
+<H3><A name="pmtu.broken">Small packets work, but large transfers fail</A>
+</H3>
+<P>If tests with ping(1) and a small packet size succeed, but tests or
+ transfers with larger packet sizes fail, suspect problems with packet
+ fragmentation and perhaps<A href="glossary.html#pathMTU"> path MTU
+ discovery</A>.</P>
+<P>Our<A href="trouble.html#bigpacket"> troubleshooting document</A>
+ covers these problems. Information on the underlying mechanism is in
+ our<A href="background.html#MTU.trouble"> background</A> document.</P>
+<H3><A name="subsub">Subnet-to-subnet works, but tests from the gateways
+ don't</A></H3>
+<P>This is described under<A href="#cantping"> I cannot ping...</A>
+ above.</P>
+<H2><A name="compile.faq">Compilation problems</A></H2>
+<H3><A name="gmp.h_missing">gmp.h: No such file or directory</A></H3>
+<P>Pluto needs the GMP (<STRONG>G</STRONG>NU</P>
+<P><STRONG>M</STRONG>ulti-<STRONG>P</STRONG>recision) library for the
+ large integer calculations it uses in<A href="glossary.html#public">
+ public key</A> cryptography. This error message indicates a failure to
+ find the library. You must install it before Pluto will compile.</P>
+<P>The GMP library is included in most Linux distributions. Typically,
+ there are two RPMs, libgmp and libgmp-devel, You need to<EM> install
+ both</EM>, either from your distribution CDs or from your vendor's web
+ site.</P>
+<P>On Debian, a mailing list message reports that the command to give is<VAR>
+ apt-get install gmp2</VAR>.</P>
+<P>For more information and the latest version, see the<A href="http://www.swox.com/gmp/">
+ GMP home page</A>.</P>
+<H3><A name="noVM">... virtual memory exhausted</A></H3>
+<P>We have had several reports of this message appearing, all on SPARC
+ Linux. Here is a mailing message on a solution:</P>
+<PRE>&gt; ipsec_sha1.c: In function `SHA1Transform':
+&gt; ipsec_sha1.c:95: virtual memory exhausted
+
+I'm seeing exactly the same problem on an Ultra with 256MB ram and 500
+MB swap.  Except I am compiling version 1.5 and its Red Hat 6.2.
+
+I can get around this by using -O instead of -O2 for the optimization
+level.  So it is probably a bug in the optimizer on the sparc complier. 
+I'll try and chase this down on the sparc lists.</PRE>
+<H2><A name="error">Interpreting error messages</A></H2>
+<H3><A name="route-client">route-client (or host) exited with status 7</A>
+</H3>
+<P>Here is a discussion of this error from FreeS/WAN &quot;listress&quot; (mailing
+ list tech support person) Claudia Schmeing. The &quot;FAQ on the network
+ unreachable error&quot; which she refers to is the next question below.</P>
+<PRE>&gt; I reached the point where the two boxes (both on dial-up connections, but
+&gt; treated as static IPs by getting the IP and editing ipsec.conf after the
+&gt; connection is established) to the point where they exchange some info, but I
+&gt; get an error like &quot;route-client command exited with status 7 \n internal
+&gt; error&quot;.
+&gt; Where can I find a description of this error?
+
+In general, if the FAQ doesn't cover it, you can search the mailing list 
+archives - I like to use
+http://www.sandelman.ottawa.on.ca/linux-ipsec/
+but you can see doc/mail.html for different archive formats.
+
+
+Your error comes from the _updown script, which performs some
+routing and firewall functions to help Linux FreeS/WAN. More info
+is available at doc/firewall.html and man ipsec.conf. Its routing
+is integral to the health of Linux FreeS/WAN; it also provides facility
+to insert custom firewall rules to be executed when you create or destroy
+a connection.
+
+Yours is, of course, a routing error. You can be fairly sure the routing 
+machinery is saying &quot;network is unreachable&quot;. There's a FAQ on the 
+&quot;network is unreachable&quot; error, but more information is available now; read on.
+
+If your _updown script is recent (for example if it shipped with 
+Linux FreeS/WAN 1.91), you will see another debugging line in your logs 
+that looks something like this:
+
+&gt; output: /usr/local/lib/ipsec/_updown: `route add -net 128.174.253.83 
+&gt; netmask 255.255.255.255 dev ipsec0 gw 66.92.93.161' failed
+
+This is, of course, the system route command that exited with status 7, 
+(ie. failed). Man route for details. Seeing the command typed out yields 
+more information. If your _updown script is older, you may wish to update 
+it to show the command explicitly.
+
+Three parameters fed to the route command: net, netmask and gw [gateway] 
+are derived from things you've put in ipsec.conf.
+
+Net and netmask are derived from the peer's IP and mask. In more detail:
+
+You may see a routing error when routing to a client (ie. subnet), or 
+to a host (IPSec gateway or freestanding host; a box that does IPSec for
+itself). In _updown, the &quot;route-client&quot; section  is responsible to set up 
+the route for IPSec'd (usually, read 'tunneled') packets headed to a 
+peer subnet. Similarly, route-host routes IPSec'd packets to a peer host
+or IPSec gateway.
+
+When routing to a 'client', net and netmask are ipsec.conf's left- or 
+rightsubnet (whichever is not local). Similarly, when routing to a 
+'host' the net is left or right. Host netmask is always /32, indicating a 
+single machine.
+
+Gw is nexthop's value. Again, the value in question is left- or rightnexthop,
+whichever is local. Where left/right or left-/rightnexthop has the special 
+value %defaultroute (described in man ipsec.conf), gw will automagically get
+the value of the next hop on the default route.
+
+Q: &quot;What's a nexthop and why do I need one?&quot;
+
+A: 'nexthop' is a routing kluge; its value is the next hop away
+   from the machine that's doing IPSec, and toward your IPSec peer. 
+   You need it to get the processed packets out of the local system and 
+   onto the wire. While we often route other packets through the machine 
+   that's now doing IPSec, and are done with it, this does not suffice here. 
+   After packets are processed with IPSec, this machine needs to know where 
+   they go next. Of course using the 'IPSec gateway' as their routing gateway 
+   would cause an infinite loop! [To visualize this, see the packet flow 
+   diagram at doc/firewall.html.] To avoid this, we route packets through 
+   the next hop down their projected path.
+
+Now that you know the background, consider:
+1. Did you test routing between the gateways in the absence of Linux
+   FreeS/WAN, as recommended? You need to ensure the two machines that
+   will be running Linux FreeS/WAN can route to one another before trying to 
+   make a secure connection.
+2. Is there anything obviously wrong with the sense of your route command?
+
+Normally, this problem is caused by an incorrect local nexthop parameter.
+Check out the use of %defaultroute, described in man ipsec.conf. This is
+a simple way to set nexthop for most people. To figure nexthop out by hand,
+traceroute in-the-clear to your IPSec peer. Nexthop is the traceroute's 
+first hop after your IPSec gateway.</PRE>
+<H3><A name="unreachable">SIOCADDRT:Network is unreachable</A></H3>
+<P>This message is not from FreeS/WAN, but from the Linux IP stack
+ itself. That stack is seeing packets it has no route for, either
+ because your routing was broken before FreeS/WAN started or because
+ FreeS/WAN's changes broke it.</P>
+<P>Here is a message from Claudia suggesting ways to diagnose and fix
+ such problems:</P>
+<PRE>You write,
+&gt; I have correctly installed freeswan-1.8 on RH7.0 kernel 2.2.17, but when 
+&gt; I setup a VPN connection with the other machine(RH5.2 Kernel 2.0.36 
+&gt; freeswan-1.0, it works well.) it told me that 
+&gt; &quot;SIOCADDRT:Network is unreachable&quot;!  But the network connection is no 
+&gt; problem.
+
+Often this error is the result of a misconfiguration. 
+
+Be sure that you can route successfully in the absence of Linux
+FreeS/WAN. (You say this is no problem, so proceed to the next step.)
+
+Use a custom copy of the default updownscript. Do not change the route 
+commands, but add a diagnostic message revealing the exact text of the 
+route command. Is there a problem with the sense of the route command
+that you can see? If so, then re-examine those ipsec.conf settings
+that are being sent to the route command. 
+
+You may wish to use the ipsec auto --route and --unroute commands to 
+troubleshoot the problem. See man ipsec_auto for details.</PRE>
+<P>Since the above message was written, we have modified the updown
+ script to provide a better diagnostic for this problem. Check<VAR>
+ /var/log/messages</VAR>.</P>
+<P>See also the FAQ question<A href="#route-client"> route-client (or
+ host) exited with status 7</A>.</P>
+<H3><A name="modprobe">ipsec_setup: modprobe: Can't locate module ipsec</A>
+</H3>
+<H3><A name="noKLIPS">ipsec_setup: Fatal error, kernel appears to lack
+ KLIPS</A></H3>
+<P>These messages indicate an installation failure. The kernel you are
+ running does not contain the<A href="glossary.html#KLIPS"> KLIPS
+ (kernel IPsec)</A> code.</P>
+<P>Note that the &quot;modprobe: Can't locate module ipsec&quot; message appears
+ even if you are not using modules. If there is no KLIPS in your kernel,
+ FreeS/WAN tries to load it as a module. If that fails, you get this
+ message.</P>
+<P>Commands you can quickly try are:</P>
+<DL>
+<DT><VAR>uname -a</VAR></DT>
+<DD>to get details, including compilation date and time, of the
+ currently running kernel</DD>
+<DT><VAR>ls /</VAR></DT>
+<DT><VAR>ls /boot</VAR></DT>
+<DD>to ensure a new kernel is where it should be. If kernel compilation
+ puts it in<VAR> /</VAR> but<VAR> lilo</VAR> wants it in<VAR> /boot</VAR>
+, then you should uncomment the<VAR> INSTALL_PATH=/boot</VAR> line in
+ the kernel<VAR> Makefile</VAR>.</DD>
+<DT><VAR>more /etc/lilo.conf</VAR></DT>
+<DD>to see that<VAR> lilo</VAR> has correct information</DD>
+<DT><VAR>lilo</VAR></DT>
+<DD>to ensure that information in<VAR> /etc/lilo.conf</VAR> has been
+ transferred to the boot sector</DD>
+</DL>
+<P>If those don't find the problem, you have to go back and check
+ through the<A href="install.html"> install</A> procedure to see what
+ was missed.</P>
+<P>Here is one of Claudia's messages on the topic:</P>
+<PRE>&gt; I tried to install freeswan 1.8 on my mandrake 7.2 test box. ...
+
+&gt; It does show version and some output for whack.
+
+Yes, because the Pluto (daemon) part of ipsec is installed correctly, but
+as we see below the kernel portion is not.
+
+&gt; However, I get the following from /var/log/messages:
+&gt; 
+&gt; Mar 11 22:11:55 pavillion ipsec_setup: Starting FreeS/WAN IPsec 1.8...
+&gt; Mar 11 22:12:02 pavillion ipsec_setup: modprobe: Can't locate module ipsec
+&gt; Mar 11 22:12:02 pavillion ipsec_setup: Fatal error, kernel appears to lack
+&gt; KLIPS.
+
+This is your problem. You have not successfully installed a kernel with
+IPSec machinery in it. 
+
+Did you build Linux FreeS/WAN as a module? If so, you need to ensure that 
+your new module has been installed in the directory where your kernel 
+loader normally finds your modules. If not, you need to ensure
+that the new IPSec-enabled kernel is being loaded correctly.
+
+See also doc/install.html, and INSTALL in the distro.</PRE>
+<H3><A name="noDNS">ipsec_setup: ... failure to fetch key for ... from
+ DNS</A></H3>
+<P>Quoting Henry:</P>
+<PRE>Note that by default, FreeS/WAN is now set up to
+     (a) authenticate with RSA keys, and
+     (b) fetch the public key of the far end from DNS.
+Explicit attention to  ipsec.conf will be needed if you want
+to do something different.</PRE>
+<P>and Claudia, responding to the same user:</P>
+<PRE>You write,
+
+&gt;       My current setup in ipsec.conf is leftrsasigkey=%dns I have 
+&gt; commented this and authby=rsasig out. I am able to get ipsec running, 
+&gt; but what I find is that the documentation only specifies for %dns are 
+&gt; there any other values that can be placed in this variable other than 
+&gt; %dns and the key? I am also assuming that this is where I would place 
+&gt; my public key for the left and right side as well is this correct?
+
+Valid values for authby= are rsasig and secret, which entail authentication
+by RSA signature or by shared secret, respectively. Because you have 
+commented authby=rsasig out, you are using the default value of authby=secret. 
+
+When using RSA signatures, there are two ways to get the public key for the
+IPSec peer: either copy it directly into *rsasigkey= in ipsec.conf, or
+fetch it from dns. The magic value %dns for *rsasigkey parameters says to 
+try to fetch the peer's key from dns.
+
+For any parameters, you may find their significance and special values in
+man ipsec.conf. If you are setting up keys or secrets, be sure also to
+reference man ipsec.secrets.</PRE>
+<H3><A name="dup_address">ipsec_setup: ... interfaces ... and ... share
+ address ...</A></H3>
+<P>This is a fatal error. FreeS/WAN cannot cope with two or more
+ interfaces using the same IP address. You must re-configure to avoid
+ this.</P>
+<P>A mailing list message on the topic from Pluto developer Hugh
+ Redelmeier:</P>
+<PRE>| I'm trying to get freeswan working between two machine where one has a ppp
+| interface.
+| I've already suceeded with  two machines with ethernet ports but  the ppp
+| interface is causing me problems.
+|  basically when I run ipsec start  i get
+| ipsec_setup: Starting FreeS/WAN IPsec 1.7...
+| ipsec_setup: 003 IP interfaces ppp1 and ppp0 share address 192.168.0.10!
+| ipsec_setup: 003 IP interfaces ppp1 and ppp2 share address 192.168.0.10!
+| ipsec_setup: 003 IP interfaces ppp0 and ppp2 share address 192.168.0.10!
+| ipsec_setup: 003 no public interfaces found
+|
+| followed by lots of cannot work out interface for connection messages
+|
+| now I can specify the interface in ipsec.conf to be ppp0 , but this does
+| not affect the above behaviour. A quick look in server.c indicates that the
+| interfaces value  is not used but some sort of raw detect happens.
+|
+| I guess I could prevent the formation of the extra ppp interfaces or
+| allocate them different ip but I'd  rather not. if at all possible. Any
+| suggestions please.
+
+Pluto won't touch an interface that shares an IP address with another.
+This will eventually change, but it probably won't happen soon.
+
+For now, you will have to give the ppp1 and ppp2 different addresses.</PRE>
+<H3><A name="kflags">ipsec_setup: Cannot adjust kernel flags</A></H3>
+<P>A mailing list message form technical lead Henry Spencer:</P>
+<PRE>&gt; When FreeS/WAN IPsec 1.7 is starting on my 2.0.38 Linux kernel the following
+&gt; error message is generated:
+&gt; ipsec_setup: Cannot adjust kernel flags, no /proc/sys/net/ipsec directory!
+&gt; What is supposed to create this directory and how can I fix this problem?
+
+I think that directory is a 2.2ism, although I'm not certain (I don't have
+a 2.0.xx system handy any more for testing).  Without it, some of the
+ipsec.conf config-setup flags won't work, but otherwise things should
+function. </PRE>
+<P>You also need to enable the<VAR> /proc</VAR> filesystem in your
+ kernel configuration for these operations to work.</P>
+<H3><A name="message_num">Message numbers (MI3, QR1, et cetera) in Pluto
+ messages</A></H3>
+<P>Pluto messages often indicate where Pluto is in the IKE protocols.
+ The letters indicate<STRONG> M</STRONG>ain mode or<STRONG> Q</STRONG>
+uick mode and<STRONG> I</STRONG>nitiator or<STRONG> R</STRONG>esponder.
+ The numerals are message sequence numbers. For more detail, see our<A href="ipsec.html#sequence">
+ IPsec section</A>.</P>
+<H3><A name="conn_name">Connection names in Pluto error messages</A></H3>
+<P>From Pluto programmer Hugh Redelmeier:</P>
+<PRE>| Jan 17 16:21:10 remus Pluto[13631]: &quot;jumble&quot; #1: responding to Main Mode from Road Warrior 130.205.82.46
+| Jan 17 16:21:11 remus Pluto[13631]: &quot;jumble&quot; #1: no suitable connection for peer @banshee.wittsend.com
+| 
+|     The connection &quot;jumble&quot; has nothing to do with the incoming
+| connection requests, which were meant for the connection &quot;banshee&quot;.
+
+You are right.  The message tells you which Connection Pluto is
+currently using, which need not be the right one.  It need not be the
+right one now for the negotiation to eventually succeed!  This is
+described in ipsec_pluto(8) in the section &quot;Road Warrior Support&quot;.
+
+There are two times when Pluto will consider switching Connections for
+a state object.  Both are in response to receiving ID payloads (one in
+Phase 1 / Main Mode and one in Phase 2 / Quick Mode).  The second is
+not unique to Road Warriors.  In fact, neither is the first any more
+(two connections for the same pair of hosts could differ in Phase 1 ID
+payload; probably nobody else has tried this).</PRE>
+<H3><A name="cantorient">Pluto: ... can't orient connection</A></H3>
+<P>Older versions of FreeS/WAN used this message. The same error now
+ gives the &quot;we have no ipsecN ...&quot; error described just below.</P>
+<H3><A name="no.interface">... we have no ipsecN interface for either
+ end of this connection</A></H3>
+<P>Your tunnel has no IP address which matches the IP address of any of
+ the available IPsec interfaces. Either you've misconfigured the
+ connection, or you need to define an appropriate IPsec interface
+ connection.<VAR> interfaces=%defaultroute</VAR> works in many cases.</P>
+<P>A longer story: Pluto needs to know whether it is running on the
+ machine which the connection description calls<VAR> left</VAR> or on<VAR>
+ right</VAR>. It figures that out by:</P>
+<UL>
+<LI>looking at the interfaces given in<VAR> interfaces=</VAR> lines in
+ the<VAR> config setup</VAR> section</LI>
+<LI>discovering the IP addresses for those interfaces</LI>
+<LI>searching for a match between those addresses and the ones given in<VAR>
+ left=</VAR> or<VAR> right=</VAR> lines.</LI>
+</UL>
+<P>Normally a match is found. Then Pluto knows where it is and can set
+ up other things (for example, if it is<VAR> left</VAR>) using
+ parameters such as<VAR> leftsubnet</VAR> and<VAR> leftnexthop</VAR>,
+ and sending its outgoing packets to<VAR> right</VAR>.</P>
+<P>If no match is found, it emits the above error message.</P>
+<H3><A name="noconn">Pluto: ... no connection is known</A></H3>
+<P>This error message occurs when a remote system attempts to negotiate
+ a connection and Pluto does not have a connection description that
+ matches what the remote system has requested. The most common cause is
+ a configuration error on one end or the other.</P>
+<P>Parameters involved in this match are<VAR> left</VAR>,<VAR> right</VAR>
+,<VAR> leftsubnet</VAR> and<VAR> rightsubnet</VAR>.</P>
+<P><STRONG>The match must be exact</STRONG>. For example, if your left
+ subnet is a.b.c.0/24 then neither a single machine in that net nor a
+ smaller subnet such as a.b.c.64/26 will be considered a match.</P>
+<P>The message can also occur when an appropriate description exists but
+ Pluto has not loaded it. Use an<VAR> auto=add</VAR> statement in the
+ connection description, or an<VAR> ipsec auto --add &lt;conn_name&gt;</VAR>
+ command, to correct this.</P>
+<P>An explanation from the Pluto developer:</P>
+<PRE>| Jul 12 15:00:22 sohar58 Pluto[574]: &quot;corp_road&quot; #2: cannot respond to IPsec
+| SA request because no connection is known for
+| 216.112.83.112/32===216.112.83.112...216.67.25.118
+
+This is the first message from the Pluto log showing a problem.  It
+means that PGPnet is trying to negotiate a set of SAs with this
+topology:
+
+216.112.83.112/32===216.112.83.112...216.67.25.118
+^^^^^^^^^^^^^^^^^   ^^^^^^^^^^^^^^   ^^^^^^^^^^^^^
+client on our side  our host         PGPnet host, no client
+
+None of the conns you showed look like this.
+
+Use
+        ipsec auto --status
+to see a snapshot of what connections are in pluto, what
+negotiations are going on, and what SAs are established.
+
+The leftsubnet= (client) in your conn is 216.112.83.64/26.  It must
+exactly match what pluto is looking for, and it does not.</PRE>
+<H3><A name="nosuit">Pluto: ... no suitable connection ...</A></H3>
+<P>This is similar to the<A href="#noconn"> no connection known</A>
+ error, but occurs at a different point in Pluto processing.</P>
+<P>Here is one of Claudia's messages explaining the problem:</P>
+<PRE>You write,
+
+&gt; What could be the reason of the following error? 
+&gt; &quot;no suitable connection for peer '@xforce'&quot;
+
+When a connection is initiated by the peer, Pluto must choose which entry in 
+the conf file best matches the incoming connection. A preliminary choice is 
+made on the basis of source and destination IPs, since that information is 
+available at that time. 
+
+A payload containing an ID arrives later in the negotiation. Based on this
+id and the *id= parameters, Pluto refines its conn selection. ...
+
+The message &quot;no suitable connection&quot; indicates that in this refining step,
+Pluto does not find a connection that matches that ID.
+
+Please see &quot;Selecting a connection when responding&quot; in man ipsec_pluto for
+more details.</PRE>
+<P>See also<A href="#conn_name"> Connection names in Pluto error
+ messages</A>.</P>
+<H3><A name="noconn.auth">Pluto: ... no connection has been authorized</A>
+</H3>
+<P>Here is one of Claudia's messages discussing this problem:</P>
+<PRE>You write,
+
+&gt;  May 22 10:46:31 debian Pluto[25834]: packet from x.y.z.p:10014: 
+&gt;  initial Main Mode message from x.y.z.p:10014 
+                            but no connection has been authorized
+
+This error occurs early in the connection negotiation process,
+at the first step of IKE negotiation (Main Mode), which is itself the 
+first of two negotiation phases involved in creating an IPSec connection.
+
+Here, Linux FreeS/WAN receives a packet from a potential peer, which 
+requests that they begin discussing a connection.
+
+The &quot;no connection has been authorized&quot; means that there is no connection 
+description in Linux FreeS/WAN's internal database that can be used to 
+link your ipsec interface with that peer.
+
+&quot;But of course I configured that connection!&quot; 
+
+It may be that the appropriate connection description exists in ipsec.conf 
+but has not been added to the database with ipsec auto --add myconn or the 
+auto=add method. Or, the connection description may be misconfigured.
+
+The only parameters that are relevant in this decision are left= and right= .
+Local and remote ports are also taken into account -- we see that the port 
+is printed in the message above -- but there is no way to control these
+in ipsec.conf.
+
+
+Failure at &quot;no connection has been authorized&quot; is similar to the
+&quot;no connection is known for...&quot; error in the FAQ, and the &quot;no suitable
+connection&quot; error described in the snapshot's FAQ. In all three cases,
+Linux FreeS/WAN is trying to match parameters received in the
+negotiation with the connection description in the local config file.
+
+As it receives more information, its matches take more parameters into 
+account, and become more precise:  first the pair of potential peers,
+then the peer IDs, then the endpoints (including any subnets).
+
+The &quot;no suitable connection for peer *&quot; occurs toward the end of IKE 
+(Main Mode) negotiation, when the IDs are matched.
+
+&quot;no connection is known for a/b===c...d&quot; is seen at the beginning of IPSec 
+(Quick Mode, phase 2) negotiation, when the connections are matched using
+left, right, and any information about the subnets.</PRE>
+<H3><A name="noDESsupport">Pluto: ... OAKLEY_DES_CBC is not supported.</A>
+</H3>
+<P>This message occurs when the other system attempts to negotiate a
+ connection using<A href="glossary.html#DES"> single DES</A>, which we
+ do not support because it is<A href="politics.html#desnotsecure">
+ insecure</A>.</P>
+<P>Our interoperation document has suggestions for<A href="interop.html#noDES">
+ how to deal with</A> systems that attempt to use single DES.</P>
+<H3><A name="notransform">Pluto: ... no acceptable transform</A></H3>
+<P>This message means that the other gateway has made a proposal for
+ connection parameters, but nothing they proposed is acceptable to
+ Pluto. Possible causes include:</P>
+<UL>
+<LI>misconfiguration on either end</LI>
+<LI>policy incompatibilities, for example we require encrypted
+ connections but they are trying to create one with just authentication</LI>
+<LI>interoperation problems, for example they offer only single DES and
+ FreeS/WAN does not support that. See<A href="interop.html#interop.problem">
+ discussion</A> in our interoperation document.</LI>
+</UL>
+<P>A more detailed explanation, from Pluto programmer Hugh Redelmeier:</P>
+<PRE>Background:
+
+When one IKE system (for example, Pluto) is negotiating with another
+to create an SA, the Initiator proposes a bunch of choices and the
+Responder replies with one that it has selected.
+
+The structure of the choices is fairly complicated.  An SA payload
+contains a list of lists of &quot;Proposals&quot;.  The outer list is a set of
+choices: the selection must be from one element of this list.
+
+Each of these elements is a list of Proposals.  A selection must be
+made from each of the elements of the inner list.  In other words,
+*all* of them apply (that is how, for example, both AH and ESP can
+apply at once).
+
+Within each of these Proposals is a list of Transforms.  For each
+Proposal selected, one Transform must be selected (in other words,
+each Proposal provides a choice of Transforms).
+
+Each Transform is made up of a list of Attributes describing, well,
+attributes.  Such as lifetime of the SA.  Such as algorithm to be
+used.  All the Attributes apply to a Transform.
+
+You will have noticed a pattern here: layers alternate between being
+disjunctions (&quot;or&quot;) and conjunctions (&quot;and&quot;).
+
+For Phase 1 / Main Mode (negotiating an ISAKMP SA), this structure is
+cut back.  There must be exactly one Proposal.  So this degenerates to
+a list of Transforms, one of which must be chosen.
+
+In your case, no proposal was considered acceptable to Pluto (the
+Responder).  So negotiation ceased.  Pluto logs the reason it rejects
+each Transform.  So look back in the log to see what is going wrong.</PRE>
+<H3><A name="rsasigkey">rsasigkey dumps core</A></H3>
+ A comment on this error from Henry:
+<PRE>On Fri, 29 Jun 2001, Rodrigo Gruppelli wrote:
+&gt; ...Well, it seem that there's
+&gt; another problem with it. When I try to generate a pair of RSA keys,
+&gt; rsasigkey cores dump...
+
+*That* is a neon sign flashing &quot;GMP LIBRARY IS BROKEN&quot;.  Rsasigkey calls
+GMP a lot, and our own library a little bit, and that's very nearly all it
+does.  Barring bugs in its code or our library -- which have happened, but
+not very often -- a problem in rsasigkey is a problem in GMP.</PRE>
+<P>See the next question for how to deal with GMP errors.</P>
+<H3><A name="sig4">!Pluto failure!: ... exited with ... signal 4</A></H3>
+<P>Pluto has died. Signal 4 is SIGILL, illegal instruction.</P>
+<P>The most likely cause is that your<A href="glossary.html#GMP"> GMP</A>
+ (GNU multi-precision) library is compiled for a different processor
+ than what you are running on. Pluto uses that library for its public
+ key calculations.</P>
+<P>Try getting the GMP sources and recompile for your processor type.
+ Most Linux distributions will include this source, or you can download
+ it from the<A href="http://www.swox.com/gmp/"> GMP home page</A>.</P>
+<H3><A name="econnrefused">ECONNREFUSED error message</A></H3>
+<P>From John Denker, on the mailing list:</P>
+<PRE>1)  The log message
+  some IKE message we sent has been rejected with 
+  ECONNREFUSED (kernel supplied no details)
+is much more suitable than the previous version.  Thanks.
+
+2) Minor suggestion for further improvement: it might be worth mentioning
+that the command
+  tcpdump -i eth1 icmp[0] != 8 and icmp[0] != 0
+is useful for tracking down the details in question.  We shouldn't expect
+all IPsec users to figure that out on their own.  The log message might
+even provide a hint as to where to look in the docs.</PRE>
+<P>Reply From Pluto developer Hugh Redelmeier</P>
+<PRE>Good idea.
+
+I've added a bit pluto(8)'s BUGS section along these lines.
+I didn't have the heart to lengthen this message.</PRE>
+<H3><A name="no_eroute">klips_debug: ... no eroute!</A></H3>
+<P>This message means<A href="glossary.html#KLIPS"> KLIPS</A> has
+ received a packet for which no IPsec tunnel has been defined.</P>
+<P>Here is a more detailed duscussion from the team's tech support
+ person Claudia Schmeing, responding to a query on the mailing list:</P>
+<PRE>&gt; Why ipsec reports no eroute! ???? IP Masq... is disabled.
+
+In general, more information is required so that people on the list may
+give you informed input. See doc/prob.report.</PRE>
+<P>The document she refers to has since been replaced by a<A href="trouble.html#prob.report">
+ section</A> of the troubleshooting document.</P>
+<PRE>However, I can make some general comments on this type of error.
+
+This error usually looks something like this (clipped from an archived
+message):
+
+&gt; ttl:64 proto:1 chk:45459 saddr:192.168.1.2 daddr:192.168.100.1
+&gt; ... klips_debug:ipsec_findroute: 192.168.1.2-&gt;192.168.100.1
+&gt; ... klips_debug:rj_match: * See if we match exactly as a host destination
+&gt; ... klips_debug:rj_match: ** try to match a leaf, t=0xc1a260b0
+&gt; ... klips_debug:rj_match: *** start searching up the tree, t=0xc1a260b0
+&gt; ... klips_debug:rj_match: **** t=0xc1a260c8
+&gt; ... klips_debug:rj_match: **** t=0xc1fe5960
+&gt; ... klips_debug:rj_match: ***** not found.
+&gt; ... klips_debug:ipsec_tunnel_start_xmit: Original head/tailroom: 2, 28
+&gt; ... klips_debug:ipsec_tunnel_start_xmit: no eroute!: ts=47.3030, dropping.
+
+
+What does this mean?
+- --------------------
+
+&quot;eroute&quot; stands for &quot;extended route&quot;, and is a special type of route 
+internal to Linux FreeS/WAN. For more information about this type of route, 
+see the section of man ipsec_auto on ipsec auto --route.
+
+&quot;no eroute!&quot; here means, roughly, that Linux FreeS/WAN cannot find an 
+appropriate tunnel that should have delivered this packet. Linux 
+FreeS/WAN therefore drops the packet, with the message &quot;no eroute! ...
+dropping&quot;, on the assumption that this packet is not a legitimate 
+transmission through a properly constructed tunnel.
+
+
+How does this situation come about?
+- -----------------------------------
+
+Linux FreeS/WAN has a number of connection descriptions defined in 
+ipsec.conf. These must be successfully brought &quot;up&quot; to form actual tunnels.
+(see doc/setup.html's step 15, man ipsec.conf and man ipsec_auto 
+for details).
+
+Such connections are often specific to the endpoints' IPs. However, in 
+some cases they may be more general, for example in the case of 
+Road Warriors where left or right is the special value %any.
+
+When Linux FreeS/WAN receives a packet, it verifies that the packet has
+come through a legitimate channel, by checking that there is an
+appropriate tunnel through which this packet might legitimately have
+arrived. This is the process we see above.
+
+First, it checks for an eroute that exactly matches the packet. In the 
+example above, we see it checking for a route that begins at 192.168.1.2
+and ends at 192.168.100.1. This search favours the most specific match that
+would apply to the route between these IPs. So, if there is a connection 
+description exactly matching these IPs, the search will end there. If not, 
+the code will search for a more general description matching the IPs.
+If there is no match, either specific or general, the packet will be
+dropped, as we see, above.
+
+Unless you are working with Road Warriors, only the first, specific part 
+of the matching process is likely to be relevant to you.
+
+
+&quot;But I defined the tunnel, and it came up, why do I have this error?&quot;
+- ---------------------------------------------------------------------
+
+One of the most common causes of this error is failure to specify enough
+connection descriptions to cover all needed tunnels between any two 
+gateways and their respective subnets. As you have noticed, troubleshooting
+this error may be complicated by the use of IP Masq. However, this error is
+not limited to cases where IP Masq is used. 
+
+See doc/configuration.html#multitunnel for a detailed example of the 
+solution to this type of problem.</PRE>
+<P>The documentation section she refers to is now<A href="adv_config.html#multitunnel">
+ here</A>.</P>
+<H3><A name="SAused">... trouble writing to /dev/ipsec ... SA already in
+ use</A></H3>
+<P>This error message occurs when two manual connections are set up with
+ the same SPI value.</P>
+<P>See the FAQ for<A href="#spi_error"> One manual connection works, but
+ second one fails</A>.</P>
+<H3><A name="ignore">... ignoring ... payload</A></H3>
+<P>This message is harmless. The IKE protocol provides for a number of
+ optional messages types:</P>
+<UL>
+<LI>delete SA</LI>
+<LI>initial contact</LI>
+<LI>vendor ID</LI>
+<LI>...</LI>
+</UL>
+<P>An implementation is never required to send these, but they are
+ allowed to. The receiver is not required to do anything with them.
+ FreeS/WAN ignores them, but notifies you via the logs.</P>
+<P>For the &quot;ignoring delete SA Payload&quot; message, see also our discussion
+ of cleaning up<A href="#deadtunnel"> dead tunnels</A>.</P>
+<H3><A name="unknown_rightcert">unknown parameter name &quot;rightcert&quot;</A></H3>
+<P>This message can appear when you've upgraded an X.509-enabled Linux
+ FreeS/WAN with a vanilla Linux FreeS/WAN. To use your X.509 configs you
+ will need to overwrite the new install with<A HREF="http://www.freeswan.ca">
+ Super FreeS/WAN</A>, or add the<A HREF="http://www.strongsec.ca/freeswan">
+ X.509 patch</A> by hand.</P>
+<H2><A name="spam">Why don't you restrict the mailing lists to reduce
+ spam?</A></H2>
+<P>As a matter of policy, some of our<A href="mail.html"> mailing lists</A>
+ need to be open to non-subscribers. Project management feel strongly
+ that maintaining this openness is more important than blocking spam.</P>
+<UL>
+<LI>Users should be able to get help or report bugs without subscribing.</LI>
+<LI>Even a user who is subscribed may not have access to his or her
+ subscribed account when he or she needs help, miles from home base in
+ the middle of setting up a client's gateway.</LI>
+<LI>There is arguably a legal requirement for this policy. A US resident
+ or citizen could be charged under munitions export laws for providing
+ technical assistance to a foreign cryptographic project. Such a charge
+ would be more easily defended if the discussion takes place in public,
+ on an open list.</LI>
+</UL>
+<P>This has been discussed several times at some length on the list. See
+ the<A href="mail.html#archive"> list archives</A>. Bringing the topic
+ up again is unlikely to be useful. Please don't. Or at the very least,
+ please don't without reading the archives and being certain that
+ whatever you are about to suggest has not yet been discussed.</P>
+<P>Project technical lead Henry Spencer summarised one discussion:</P>
+<BLOCKQUOTE> For the third and last time: this list *will* *not* do
+ address-based filtering. This is a policy decision, not an
+ implementation problem. The decision is final, and is not open to
+ discussion. This needs to be communicated better to people, and steps
+ are being taken to do that.</BLOCKQUOTE>
+<P>Adding this FAQ section is one of the steps he refers to.</P>
+<P>You have various options other than just putting up with the spam,
+ filtering it yourself, or unsubscribing:</P>
+<UL>
+<LI>subscribe only to one or both of our lists with restricted posting
+ rules:
+<UL>
+<LI><A href="mailto:briefs@lists.freeswan.org?body=subscribe">briefs</A>
+, weekly list summaries</LI>
+<LI><A href="mailto:announce@lists.freeswan.org?body=subscribe">announce</A>
+, project-related announcements</LI>
+</UL>
+</LI>
+<LI>read the other lists via the<A href="mail.html#archive"> archives</A>
+</LI>
+</UL>
+<P>A number of tools are available to filter mail.</P>
+<UL>
+<LI>Many mail readers include some filtering capability.</LI>
+<LI>Many Linux distributions include<A href="http://www.procmail.org/">
+ procmail(8)</A> for server-side filtering.</LI>
+<LI>The<A href="http://www.spambouncer.org/"> Spam Bouncer</A> is a set
+ of procmail(8) filters designed to combat spam.</LI>
+<LI>Roaring Penguin have a<A href="http://www.roaringpenguin.com/mimedefang/">
+ MIME defanger</A> that removes potentially dangerous attachments.</LI>
+</UL>
+<P>If you use your ISP's mail server rather than running your own,
+ consider suggesting to the ISP that they tag suspected spam as<A href="http://www.msen.com/1997/spam.html#SUSPECTED">
+ this ISP</A> does. They could just refuse mail from dubious sources,
+ but that is tricky and runs some risk of losing valuable mail or
+ senselessly annoying senders and their admins. However, they can safely
+ tag and deliver dubious mail. The tags can greatly assist your
+ filtering.</P>
+<P>For information on tracking down spammers, see these<A href="http://www.rahul.net/falk/#howtos">
+ HowTos</A>, or the<A href="http://www.sputum.com/index2.html"> Sputum</A>
+ site. Sputum have a Linux anti-spam screensaver available for download.</P>
+<P>Here is a more detailed message from Henry:</P>
+<PRE>On Mon, 15 Jan 2001, Jay Vaughan wrote:
+&gt; I know I'm flogging a dead horse here, but I'm curious as to the reasons for
+&gt; an aversion for a subscriber-only mailing list?
+
+Once again:  for legal reasons, it is important that discussions of these
+things be held in a public place -- the list -- and we do not want to
+force people to subscribe to the list just to ask one question, because
+that may be more than merely inconvenient for them.  There are also real
+difficulties with people who are temporarily forced to use alternate
+addresses; that is precisely the time when they may be most in need of
+help, yet a subscribers-only policy shuts them out.
+
+These issues do not apply to most mailing lists, but for a list that is
+(necessarily) the primary user support route for a crypto package, they
+are very important.  This is *not* an ordinary mailing list; it has to
+function under awkward constraints that make various simplistic solutions
+inapplicable or undesirable. 
+
+&gt; We're *ALL* sick of hearing about list management problems, not just you
+&gt; old-timers, so why don't you DO SOMETHING EFFECTIVE ABOUT IT...
+
+Because it's a lot harder than it looks, and many existing &quot;solutions&quot;
+have problems when examined closely.
+
+&gt; A suggestion for you, based on 10 years of experience with management of my
+&gt; own mailing lists would be to use mailman, which includes pretty much every
+&gt; feature under the sun that you guys need and want, plus some.  The URL for
+&gt; mailman...
+
+I assure you, we're aware of mailman.  Along with a whole bunch of others,
+including some you almost certainly have never heard of (I hadn't!).
+
+&gt; As for the argument that the list shouldn't be configured to enforce
+&gt; subscription - I contend that it *SHOULD* AT LEAST require manual address
+&gt; verification in order for posts to be redirected.
+
+You do realize, I hope, that interposing such a manual step might cause
+your government to decide that this is not truly a public forum, and thus
+you could go to jail if you don't get approval from them before mailing to
+it?  If you think this sounds irrational, your government is noted for
+making irrational decisions in this area; we can't assume that they will
+suddenly start being sensible.  See above about awkward constraints.  You
+may be willing to take the risk, but we can't, in good conscience, insist
+that all users with problems do so. 
+
+                                                          Henry Spencer
+                                                       henry@spsystems.net</PRE>
+<P>and a message on the topic from project leader John Gilmore:</P>
+<PRE>Subject: Re: The linux-ipsec list's topic
+   Date: Sat, 30 Dec 2000
+   From: John Gilmore &lt;gnu@toad.com&gt;
+
+I'll post this single message, once only, in this discussion, and then
+not burden the list with any further off-topic messages.  I encourage
+everyone on the list to restrain themself from posting ANY off-topic
+messages to the linux-ipsec list.
+
+The topic of the linux-ipsec mailing list is the FreeS/WAN software.
+
+I frequently see &quot;discussions about spam on a list&quot; overwhelm the
+volume of &quot;actual spam&quot; on a list. BOTH kinds of messages are
+off-topic messages.  Twenty anti-spam messages take just as long to
+detect and discard as twenty spam messages.
+
+The Linux-ipsec list encourages on-topic messages from people who have
+not joined the list itself.  We will not censor messages to the list
+based on where they originate, or what return address they contain.
+In other words, non-subscribers ARE allowed to post, and this will not
+change.  My own valid contributions have been rejected out-of-hand by
+too many other mailing lists for me to want to impose that censorship
+on anybody else's contributions.  And every day I see the damage that
+anti-spam zeal is causing in many other ways; that zeal is far more
+damaging to the culture of the Internet than the nuisance of spam.
+
+In general, it is the responsibility of recipients to filter,
+prioritize, or otherwise manage the handling of email that comes to
+them.  It is not the responsibility of the rest of the Internet
+community to refrain from sending messages to recipients that they
+might not want to see.  If your software infrastructure for managing
+your incoming email is insufficient, then improve it.  If you think
+the signal-to-noise ratio on linux-ipsec is too poor, then please
+unsubscribe.  But don't further increase the noise by posting to the
+linux-ipsec list about those topics.
+
+        John Gilmore
+        founder &amp; sponsor, FreeS/WAN project</PRE>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="policygroups.html">Previous</A>
+<A HREF="manpages.html">Next</A>
+</BODY>
+</HTML>
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
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+SUB { font-size: smaller }
+SUP { font-size: smaller }
+PRE { font-family: monospace }
+--></STYLE>
+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="manpages.html">Previous</A>
+<A HREF="trouble.html">Next</A>
+<HR>
+<H1><A name="firewall">FreeS/WAN and firewalls</A></H1>
+<P>FreeS/WAN, or other IPsec implementations, frequently run on gateway
+ machines, the same machines running firewall or packet filtering code.
+ This document discusses the relation between the two.</P>
+<P>The firewall code in 2.4 and later kernels is called Netfilter. The
+ user-space utility to manage a firewall is iptables(8). See the<A href="http://netfilter.samba.org">
+ netfilter/iptables web site</A> for details.</P>
+<H2><A name="filters">Filtering rules for IPsec packets</A></H2>
+<P>The basic constraint is that<STRONG> an IPsec gateway must have
+ packet filters that allow IPsec packets</STRONG>, at least when talking
+ to other IPsec gateways:</P>
+<UL>
+<LI>UDP port 500 for<A href="glossary.html#IKE"> IKE</A> negotiations</LI>
+<LI>protocol 50 if you use<A href="glossary.html#ESP"> ESP</A>
+ encryption and/or authentication (the typical case)</LI>
+<LI>protocol 51 if you use<A href="glossary.html#AH"> AH</A>
+ packet-level authentication</LI>
+</UL>
+<P>Your gateway and the other IPsec gateways it communicates with must
+ be able to exchange these packets for IPsec to work. Firewall rules
+ must allow UDP 500 and at least one of<A href="glossary.html#AH"> AH</A>
+ or<A href="glossary.html#ESP"> ESP</A> on the interface that
+ communicates with the other gateway.</P>
+<P>For nearly all FreeS/WAN applications, you must allow UDP port 500
+ and the ESP protocol.</P>
+<P>There are two ways to set this up:</P>
+<DL>
+<DT>easier but less flexible</DT>
+<DD>Just set up your firewall scripts at boot time to allow IPsec
+ packets to and from your gateway. Let FreeS/WAN reject any bogus
+ packets.</DD>
+<DT>more work, giving you more precise control</DT>
+<DD>Have the<A href="manpage.d/ipsec_pluto.8.html"> ipsec_pluto(8)</A>
+ daemon call scripts to adjust firewall rules dynamically as required.
+ This is done by naming the scripts in the<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A> variables<VAR> prepluto=</VAR>,<VAR> postpluto=</VAR>
+,<VAR> leftupdown=</VAR> and<VAR> rightupdown=</VAR>.</DD>
+</DL>
+<P>Both methods are described in more detail below.</P>
+<H2><A name="examplefw">Firewall configuration at boot</A></H2>
+<P>It is possible to set up both firewalling and IPsec with appropriate
+ scripts at boot and then not use<VAR> leftupdown=</VAR> and<VAR>
+ rightupdown=</VAR>, or use them only for simple up and down operations.</P>
+<P>Basically, the technique is</P>
+<UL>
+<LI>allow IPsec packets (typically, IKE on UDP port 500 plus ESP,
+ protocol 50)
+<UL>
+<LI>incoming, if the destination address is your gateway (and
+ optionally, only from known senders)</LI>
+<LI>outgoing, with the from address of your gateway (and optionally,
+ only to known receivers)</LI>
+</UL>
+</LI>
+<LI>let<A href="glossary.html#Pluto"> Pluto</A> deal with IKE</LI>
+<LI>let<A href="glossary.html#KLIPS"> KLIPS</A> deal with ESP</LI>
+</UL>
+<P>Since Pluto authenticates its partners during the negotiation, and
+ KLIPS drops packets for which no tunnel has been negotiated, this may
+ be all you need.</P>
+<H3><A name="simple.rules">A simple set of rules</A></H3>
+<P>In simple cases, you need only a few rules, as in this example:</P>
+<PRE># allow IPsec
+#
+# IKE negotiations
+iptables -I INPUT  -p udp --sport 500 --dport 500 -j ACCEPT
+iptables -I OUTPUT -p udp --sport 500 --dport 500 -j ACCEPT
+# ESP encryption and authentication
+iptables -I INPUT  -p 50 -j ACCEPT
+iptables -I OUTPUT -p 50 -j ACCEPT
+</PRE>
+<P>This should be all you need to allow IPsec through<VAR> lokkit</VAR>,
+ which ships with Red Hat 9, on its medium security setting. Once you've
+ tweaked to your satisfaction, save your active rule set with:</P>
+<PRE>service iptables save</PRE>
+<H3><A name="complex.rules">Other rules</A></H3>
+ You can add additional rules, or modify existing ones, to work with
+ IPsec and with your network and policies. We give a some examples in
+ this section.
+<P>However, while it is certainly possible to create an elaborate set of
+ rules yourself (please let us know via the<A href="mail.html"> mailing
+ list</A> if you do), it may be both easier and more secure to use a set
+ which has already been published and tested.</P>
+<P>The published rule sets we know of are described in the<A href="#rules.pub">
+ next section</A>.</P>
+<H4>Adding additional rules</H4>
+ If necessary, you can add additional rules to:
+<DL>
+<DT>reject IPsec packets that are not to or from known gateways</DT>
+<DD>This possibility is discussed in more detail<A href="#unknowngate">
+ later</A></DD>
+<DT>allow systems behind your gateway to build IPsec tunnels that pass
+ through the gateway</DT>
+<DD>This possibility is discussed in more detail<A href="#through">
+ later</A></DD>
+<DT>filter incoming packets emerging from KLIPS.</DT>
+<DD>Firewall rules can recognise packets emerging from IPsec. They are
+ marked as arriving on an interface such as<VAR> ipsec0</VAR>, rather
+ than<VAR> eth0</VAR>,<VAR> ppp0</VAR> or whatever.</DD>
+</DL>
+<P>It is therefore reasonably straightforward to filter these packets in
+ whatever way suits your situation.</P>
+<H4>Modifying existing rules</H4>
+<P>In some cases rules that work fine before you add IPsec may require
+ modification to work with IPsec.</P>
+<P>This is especially likely for rules that deal with interfaces on the
+ Internet side of your system. IPsec adds a new interface; often the
+ rules must change to take account of that.</P>
+<P>For example, consider the rules given in<A href="http://www.netfilter.org/documentation/HOWTO//packet-filtering-HOWTO-5.html">
+ this section</A> of the Netfilter documentation:</P>
+<PRE>Most people just have a single PPP connection to the Internet, and don't
+want anyone coming back into their network, or the firewall:
+
+    ## Insert connection-tracking modules (not needed if built into kernel).
+    # insmod ip_conntrack
+    # insmod ip_conntrack_ftp
+
+    ## Create chain which blocks new connections, except if coming from inside.
+    # iptables -N block
+    # iptables -A block -m state --state ESTABLISHED,RELATED -j ACCEPT
+    # iptables -A block -m state --state NEW -i ! ppp0 -j ACCEPT
+    # iptables -A block -j DROP
+
+    ## Jump to that chain from INPUT and FORWARD chains.
+    # iptables -A INPUT -j block
+    # iptables -A FORWARD -j block</PRE>
+<P>On an IPsec gateway, those rules may need to be modified. The above
+ allows new connections from<EM> anywhere except ppp0</EM>. That means
+ new connections from ipsec0 are allowed.</P>
+<P>Do you want to allow anyone who can establish an IPsec connection to
+ your gateway to initiate TCP connections to any service on your
+ network? Almost certainly not if you are using opportunistic
+ encryption. Quite possibly not even if you have only explicitly
+ configured connections.</P>
+<P>To disallow incoming connections from ipsec0, change the middle
+ section above to:</P>
+<PRE>    ## Create chain which blocks new connections, except if coming from inside.
+    # iptables -N block
+    # iptables -A block -m state --state ESTABLISHED,RELATED -j ACCEPT
+    # iptables -A block -m state --state NEW -i ppp+ -j DROP
+    # iptables -A block -m state --state NEW -i ipsec+ -j DROP
+    # iptables -A block -m state --state NEW -i -j ACCEPT
+    # iptables -A block -j DROP</PRE>
+<P>The original rules accepted NEW connections from anywhere except
+ ppp0. This version drops NEW connections from any PPP interface (ppp+)
+ and from any ipsec interface (ipsec+), then accepts the survivors.</P>
+<P>Of course, these are only examples. You will need to adapt them to
+ your own situation.</P>
+<H3><A name="rules.pub">Published rule sets</A></H3>
+<P>Several sets of firewall rules that work with FreeS/WAN are
+ available.</P>
+<H4><A name="Ranch.trinity">Scripts based on Ranch's work</A></H4>
+<P>One user, Rob Hutton, posted his boot time scripts to the mailing
+ list, and we included them in previous versions of this documentation.
+ They are still available from our<A href="http://www.freeswan.org/freeswan_trees/freeswan-1.5/doc/firewall.html#examplefw">
+ web site</A>. However, they were for an earlier FreeS/WAN version so we
+ no longer recommend them. Also, they had some bugs. See this<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/04/msg00316.html">
+ message</A>.</P>
+<P>Those scripts were based on David Ranch's scripts for his &quot;Trinity
+ OS&quot; for setting up a secure Linux. Check his<A href="http://www.ecst.csuchico.edu/~dranch/LINUX/index-linux.html">
+ home page</A> for the latest version and for information on his<A href="biblio.html#ranch">
+ book</A> on securing Linux. If you are going to base your firewalling
+ on Ranch's scripts, we recommend using his latest version, and sending
+ him any IPsec modifications you make for incorporation into later
+ versions.</P>
+<H4><A name="seawall">The Seattle firewall</A></H4>
+<P>We have had several mailing lists reports of good results using
+ FreeS/WAN with Seawall (the Seattle Firewall). See that project's<A href="http://seawall.sourceforge.net/">
+ home page</A> on Sourceforge.</P>
+<H4><A name="rcf">The RCF scripts</A></H4>
+<P>Another set of firewall scripts with IPsec support are the RCF or
+ rc.firewall scripts. See their<A href="http://jsmoriss.mvlan.net/linux/rcf.html">
+ home page</A>.</P>
+<H4><A name="asgard">Asgard scripts</A></H4>
+<P><A href="http://heimdall.asgardsrealm.net/linux/firewall/">Asgard's
+ Realm</A> has set of firewall scripts with FreeS/WAN support, for 2.4
+ kernels and iptables.</P>
+<H4><A name="user.scripts">User scripts from the mailing list</A></H4>
+<P>One user gave considerable detail on his scripts, including
+ supporting<A href="glossary.html#IPX"> IPX</A> through the tunnel. His
+ message was too long to conveniently be quoted here, so I've put it in
+ a<A href="user_examples.html"> separate file</A>.</P>
+<H2><A name="updown">Calling firewall scripts, named in ipsec.conf(5)</A>
+</H2>
+<P>The<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf(5)</A>
+ configuration file has three pairs of parameters used to specify an
+ interface between FreeS/WAN and firewalling code.</P>
+<P>Note that using these is not required if you have a static firewall
+ setup. In that case, you just set your firewall up at boot time (in a
+ way that permits the IPsec connections you want) and do not change it
+ thereafter. Omit all the FreeS/WAN firewall parameters and FreeS/WAN
+ will not attempt to adjust firewall rules at all. See<A href="#examplefw">
+ above</A> for some information on appropriate scripts.</P>
+<P>However, if you want your firewall rules to change when IPsec
+ connections change, then you need to use these parameters.</P>
+<H3><A name="pre_post">Scripts called at IPsec start and stop</A></H3>
+<P>One pair of parmeters are set in the<VAR> config setup</VAR> section
+ of the<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf(5)</A> file and
+ affect all connections:</P>
+<DL>
+<DT>prepluto=</DT>
+<DD>script to be called before<A href="manpage.d/ipsec_pluto.8.html">
+ pluto(8)</A> IKE daemon is started.</DD>
+<DT>postpluto=</DT>
+<DD>script to be called after<A href="manpage.d/ipsec_pluto.8.html">
+ pluto(8)</A> IKE daemon is stopped.</DD>
+</DL>
+ These parameters allow you to change firewall parameters whenever IPsec
+ is started or stopped.
+<P>They can also be used in other ways. For example, you might have<VAR>
+ prepluto</VAR> add a module to your kernel for the secure network
+ interface or make a dialup connection, and then have<VAR> postpluto</VAR>
+ remove the module or take the connection down.</P>
+<H3><A name="up_down">Scripts called at connection up and down</A></H3>
+<P>The other parameters are set in connection descriptions. They can be
+ set in individual connection descriptions, and could even call
+ different scripts for each connection for maximum flexibility. In most
+ applications, however, it makes sense to use only one script and to
+ call it from<VAR> conn %default</VAR> section so that it applies to all
+ connections.</P>
+<P>You can:</P>
+<DL>
+<DT><STRONG>either</STRONG></DT>
+<DD>set<VAR> leftfirewall=yes</VAR> or<VAR> rightfirewall=yes</VAR> to
+ use our supplied default script</DD>
+<DT><STRONG>or</STRONG></DT>
+<DD>assign a name in a<VAR> leftupdown=</VAR> or<VAR> rightupdown=</VAR>
+ line to use your own script</DD>
+</DL>
+<P>Note that<STRONG> only one of these should be used</STRONG>. You
+ cannot sensibly use both. Since<STRONG> our default script is obsolete</STRONG>
+ (designed for firewalls using<VAR> ipfwadm(8)</VAR> on 2.0 kernels),
+ most users who need this service will<STRONG> need to write a custom
+ script</STRONG>.</P>
+<H4><A name="fw.default">The default script</A></H4>
+<P>We supply a default script named<VAR> _updown</VAR>.</P>
+<DL>
+<DT>leftfirewall=</DT>
+<DD></DD>
+<DT>rightfirewall=</DT>
+<DD>indicates that the gateway is doing firewalling and that<A href="manpage.d/ipsec_pluto.8.html">
+ pluto(8)</A> should poke holes in the firewall as required.</DD>
+</DL>
+<P>Set these to<VAR> yes</VAR> and Pluto will call our default script<VAR>
+ _updown</VAR> with appropriate arguments whenever it:</P>
+<UL>
+<LI>starts or stops IPsec services</LI>
+<LI>brings a connection up or down</LI>
+</UL>
+<P>The supplied default<VAR> _updown</VAR> script is appropriate for
+ simple cases using the<VAR> ipfwadm(8)</VAR> firewalling package.</P>
+<H4><A name="userscript">User-written scripts</A></H4>
+<P>You can also write your own script and have Pluto call it. Just put
+ the script's name in one of these<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A> lines:</P>
+<DL>
+<DT>leftupdown=</DT>
+<DD></DD>
+<DT>rightupdown=</DT>
+<DD>specifies a script to call instead of our default script<VAR>
+ _updown</VAR>.</DD>
+</DL>
+<P>Your script should take the same arguments and use the same
+ environment variables as<VAR> _updown</VAR>. See the &quot;updown command&quot;
+ section of the<A href="manpage.d/ipsec_pluto.8.html"> ipsec_pluto(8)</A>
+ man page for details.</P>
+<P>Note that<STRONG> you should not modify our _updown script in place</STRONG>
+. If you did that, then upgraded FreeS/WAN, the upgrade would install a
+ new default script, overwriting your changes.</P>
+<H3><A name="ipchains.script">Scripts for ipchains or iptables</A></H3>
+<P>Our<VAR> _updown</VAR> is for firewalls using<VAR> ipfwadm(8)</VAR>,
+ the firewall code for the 2.0 series of Linux kernels. If you are using
+ the more recent packages<VAR> ipchains(8)</VAR> (for 2.2 kernels) or<VAR>
+ iptables(8)</VAR> (2.4 kernels), then you must do one of:</P>
+<UL>
+<LI>use static firewall rules which are set up at boot time as described<A
+href="#examplefw"> above</A> and do not need to be changed by Pluto</LI>
+<LI>limit yourself to ipchains(8)'s ipfwadm(8) emulation mode in order
+ to use our script</LI>
+<LI>write your own script and call it with<VAR> leftupdown</VAR> and<VAR>
+ rightupdown</VAR>.</LI>
+</UL>
+<P>You can write a script to do whatever you need with firewalling.
+ Specify its name in a<VAR> [left|right]updown=</VAR> parameter in<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A> and Pluto will automatically call it for you.</P>
+<P>The arguments Pluto passes such a script are the same ones it passes
+ to our default _updown script, so the best way to build yours is to
+ copy ours and modify the copy.</P>
+<P>Note, however, that<STRONG> you should not modify our _updown script
+ in place</STRONG>. If you did that, then upgraded FreeS/WAN, the
+ upgrade would install a new default script, overwriting your changes.</P>
+<H2><A name="NAT">A complication: IPsec vs. NAT</A></H2>
+<P><A href="glossary.html#NAT.gloss">Network Address Translation</A>,
+ also known as IP masquerading, is a method of allocating IP addresses
+ dynamically, typically in circumstances where the total number of
+ machines which need to access the Internet exceeds the supply of IP
+ addresses.</P>
+<P>Any attempt to perform NAT operations on IPsec packets<EM> between
+ the IPsec gateways</EM> creates a basic conflict:</P>
+<UL>
+<LI>IPsec wants to authenticate packets and ensure they are unaltered on
+ a gateway-to-gateway basis</LI>
+<LI>NAT rewrites packet headers as they go by</LI>
+<LI>IPsec authentication fails if packets are rewritten anywhere between
+ the IPsec gateways</LI>
+</UL>
+<P>For<A href="glossary.html#AH"> AH</A>, which authenticates parts of
+ the packet header including source and destination IP addresses, this
+ is fatal. If NAT changes those fields, AH authentication fails.</P>
+<P>For<A href="glossary.html#IKE"> IKE</A> and<A href="glossary.html#ESP">
+ ESP</A> it is not necessarily fatal, but is certainly an unwelcome
+ complication.</P>
+<H3><A name="nat_ok">NAT on or behind the IPsec gateway works</A></H3>
+<P>This problem can be avoided by having the masquerading take place<EM>
+ on or behind</EM> the IPsec gateway.</P>
+<P>This can be done physically with two machines, one physically behind
+ the other. A picture, using SG to indicate IPsec<STRONG> S</STRONG>
+ecurity<STRONG> G</STRONG>ateways, is:</P>
+<PRE>      clients --- NAT ----- SG ---------- SG
+                  two machines</PRE>
+<P>In this configuration, the actual client addresses need not be given
+ in the<VAR> leftsubnet=</VAR> parameter of the FreeS/WAN connection
+ description. The security gateway just delivers packets to the NAT box;
+ it needs only that machine's address. What that machine does with them
+ does not affect FreeS/WAN.</P>
+<P>A more common setup has one machine performing both functions:</P>
+<PRE>      clients ----- NAT/SG ---------------SG
+                  one machine</PRE>
+<P>Here you have a choice of techniques depending on whether you want to
+ make your client subnet visible to clients on the other end:</P>
+<UL>
+<LI>If you want the single gateway to behave like the two shown above,
+ with your clients hidden behind the NAT, then omit the<VAR> leftsubnet=</VAR>
+ parameter. It then defaults to the gateway address. Clients on the
+ other end then talk via the tunnel only to your gateway. The gateway
+ takes packets emerging from the tunnel, applies normal masquerading,
+ and forwards them to clients.</LI>
+<LI>If you want to make your client machines visible, then give the
+ client subnet addresses as the<VAR> leftsubnet=</VAR> parameter in the
+ connection description and
+<DL>
+<DT>either</DT>
+<DD>set<VAR> leftfirewall=yes</VAR> to use the default<VAR> updown</VAR>
+ script</DD>
+<DT>or</DT>
+<DD>use your own script by giving its name in a<VAR> leftupdown=</VAR>
+ parameter</DD>
+</DL>
+ These scripts are described in their own<A href="#updown"> section</A>.
+<P>In this case, no masquerading is done. Packets to or from the client
+ subnet are encrypted or decrypted without any change to their client
+ subnet addresses, although of course the encapsulating packets use
+ gateway addresses in their headers. Clients behind the right security
+ gateway see a route via that gateway to the left subnet.</P>
+</LI>
+</UL>
+<H3><A name="nat_bad">NAT between gateways is problematic</A></H3>
+<P>We recommend not trying to build IPsec connections which pass through
+ a NAT machine. This setup poses problems:</P>
+<PRE>      clients --- SG --- NAT ---------- SG</PRE>
+<P>If you must try it, some references are:</P>
+<UL>
+<LI>Jean_Francois Nadeau's document on doing<A href="http://jixen.tripod.com/#NATed gateways">
+ IPsec behind NAT</A></LI>
+<LI><A href="web.html#VPN.masq">VPN masquerade patches</A> to make a
+ Linux NAT box handle IPsec packets correctly</LI>
+</UL>
+<H3><A name="NAT.ref">Other references on NAT and IPsec</A></H3>
+<P>Other documents which may be relevant include:</P>
+<UL>
+<LI>an Internet Draft on<A href="http://search.ietf.org/internet-drafts/draft-aboba-nat-ipsec-04.txt">
+ IPsec and NAT</A> which may eventually evolve into a standard solution
+ for this problem.</LI>
+<LI>an informational<A href="http://www.cis.ohio-state.edu/rfc/rfc2709.txt">
+ RFC</A>,<CITE> Security Model with Tunnel-mode IPsec for NAT Domains</CITE>
+.</LI>
+<LI>an<A href="http://www.cisco.com/warp/public/759/ipj_3-4/ipj_3-4_nat.html">
+ article</A> in Cisco's<CITE> Internet Protocol Journal</CITE></LI>
+</UL>
+<H2><A name="complications">Other complications</A></H2>
+<P>Of course simply allowing UDP 500 and ESP packets is not the whole
+ story. Various other issues arise in making IPsec and packet filters
+ co-exist and even co-operate. Some of them are summarised below.</P>
+<H3><A name="through">IPsec<EM> through</EM></A> the gateway</H3>
+<P>Basic IPsec packet filtering rules deal only with packets addressed
+ to or sent from your IPsec gateway.</P>
+<P>It is a separate policy decision whether to permit such packets to
+ pass through the gateway so that client machines can build end-to-end
+ IPsec tunnels of their own. This may not be practical if you are using<A
+href="#NAT"> NAT (IP masquerade)</A> on your gateway, and may conflict
+ with some corporate security policies.</P>
+<P>Where possible, allowing this is almost certainly a good idea. Using
+ IPsec on an end-to-end basis is more secure than gateway-to-gateway.</P>
+<P>Doing it is quite simple. You just need firewall rules that allow UDP
+ port 500 and protocols 50 and 51 to pass through your gateway. If you
+ wish, you can of course restrict this to certain hosts.</P>
+<H3><A name="ipsec_only">Preventing non-IPsec traffic</A></H3>
+ You can also filter<EM> everything but</EM> UDP port 500 and ESP or AH
+ to restrict traffic to IPsec only, either for anyone communicating with
+ your host or just for specific partners.
+<P>One application of this is for the telecommuter who might have:</P>
+<PRE>     Sunset==========West------------------East ================= firewall --- the Internet
+         home network      untrusted net        corporate network</PRE>
+<P>The subnet on the right is 0.0.0.0/0, the whole Internet. The West
+ gateway is set up so that it allows only IPsec packets to East in or
+ out.</P>
+<P>This configuration is used in AT&amp;T Research's network. For details,
+ see the<A href="intro.html#applied"> papers</A> links in our
+ introduction.</P>
+<P>Another application would be to set up firewall rules so that an
+ internal machine, such as an employees-only web server, could not talk
+ to the outside world except via specific IPsec tunnels.</P>
+<H3><A name="unknowngate">Filtering packets from unknown gateways</A></H3>
+<P>It is possible to use firewall rules to restrict UDP 500, ESP and AH
+ packets so that these packets are accepted only from known gateways.
+ This is not strictly necessary since FreeS/WAN will discard packets
+ from unknown gateways. You might, however, want to do it for any of a
+ number of reasons. For example:</P>
+<UL>
+<LI>Arguably, &quot;belt and suspenders&quot; is the sensible approach to
+ security. If you can block a potential attack in two ways, use both.
+ The only question is whether to look for a third way after implementing
+ the first two.</LI>
+<LI>Some admins may prefer to use the firewall code this way because
+ they prefer firewall logging to FreeS/WAN's logging.</LI>
+<LI>You may need it to implement your security policy. Consider an
+ employee working at home, and a policy that says traffic from the home
+ system to the Internet at large must go first via IPsec to the
+ corporate LAN and then out to the Internet via the corporate firewall.
+ One way to do that is to make<VAR> ipsec0</VAR> the default route on
+ the home gateway and provide exceptions only for UDP 500 and ESP to the
+ corporate gateway. Everything else is then routed via the tunnel to the
+ corporate gateway.</LI>
+</UL>
+<P>It is not possible to use only static firewall rules for this
+ filtering if you do not know the other gateways' IP addresses in
+ advance, for example if you have &quot;road warriors&quot; who may connect from a
+ different address each time or if want to do<A href="glossary.html#carpediem">
+ opportunistic encryption</A> to arbitrary gateways. In these cases, you
+ can accept UDP 500 IKE packets from anywhere, then use the<A href="#updown">
+ updown</A> script feature of<A href="manpage.d/ipsec_pluto.8.html">
+ pluto(8)</A> to dynamically adjust firewalling for each negotiated
+ tunnel.</P>
+<P>Firewall packet filtering does not much reduce the risk of a<A href="glossary.html#DOS">
+ denial of service attack</A> on FreeS/WAN. The firewall can drop
+ packets from unknown gateways, but KLIPS does that quite efficiently
+ anyway, so you gain little. The firewall cannot drop otherwise
+ legitmate packets that fail KLIPS authentication, so it cannot protect
+ against an attack designed to exhaust resources by making FreeS/WAN
+ perform many expensive authentication operations.</P>
+<P>In summary, firewall filtering of IPsec packets from unknown gateways
+ is possible but not strictly necessary.</P>
+<H2><A name="otherfilter">Other packet filters</A></H2>
+<P>When the IPsec gateway is also acting as your firewall, other packet
+ filtering rules will be in play. In general, those are outside the
+ scope of this document. See our<A href="web.html#firewall.linux"> Linux
+ firewall links</A> for information. There are a few types of packet,
+ however, which can affect the operation of FreeS/WAN or of diagnostic
+ tools commonly used with it. These are discussed below.</P>
+<H3><A name="ICMP">ICMP filtering</A></H3>
+<P><A href="glossary.html#ICMP.gloss">ICMP</A> is the<STRONG> I</STRONG>
+nternet<STRONG> C</STRONG>ontrol<STRONG> M</STRONG>essage<STRONG> P</STRONG>
+rotocol. It is used for messages between IP implementations themselves,
+ whereas IP used is used between the clients of those implementations.
+ ICMP is, unsurprisingly, used for control messages. For example, it is
+ used to notify a sender that a desination is not reachable, or to tell
+ a router to reroute certain packets elsewhere.</P>
+<P>ICMP handling is tricky for firewalls.</P>
+<UL>
+<LI>You definitely want some ICMP messages to get through; things won't
+ work without them. For example, your clients need to know if some
+ destination they ask for is unreachable.</LI>
+<LI>On the other hand, you do equally definitely do not want untrusted
+ folk sending arbitrary control messages to your machines. Imagine what
+ someone moderately clever and moderately malicious could do to you,
+ given control of your network's routing.</LI>
+</UL>
+<P>ICMP does not use ports. Messages are distinguished by a &quot;message
+ type&quot; field and, for some types, by an additional &quot;code&quot; field. The
+ definitive list of types and codes is on the<A href="http://www.iana.org">
+ IANA</A> site.</P>
+<P>One expert uses this definition for ICMP message types to be dropped
+ at the firewall.</P>
+<PRE># ICMP types which lack socially redeeming value.
+#  5     Redirect
+#  9     Router Advertisement
+# 10     Router Selection
+# 15     Information Request
+# 16     Information Reply
+# 17     Address Mask Request
+# 18     Address Mask Reply
+
+badicmp='5 9 10 15 16 17 18'</PRE>
+<P>A more conservative approach would be to make a list of allowed types
+ and drop everything else.</P>
+<P>Whichever way you do it, your ICMP filtering rules on a FreeS/WAN
+ gateway should allow at least the following ICMP packet types:</P>
+<DL>
+<DT>echo (type 8)</DT>
+<DD></DD>
+<DT>echo reply (type 0)</DT>
+<DD>These are used by ping(1). We recommend allowing both types through
+ the tunnel and to or from your gateway's external interface, since
+ ping(1) is an essential testing tool.
+<P>It is fairly common for firewalls to drop ICMP echo packets addressed
+ to machines behind the firewall. If that is your policy, please create
+ an exception for such packets arriving via an IPsec tunnel, at least
+ during intial testing of those tunnels.</P>
+</DD>
+<DT>destination unreachable (type 3)</DT>
+<DD>This is used, with code 4 (Fragmentation Needed and Don't Fragment
+ was Set) in the code field, to control<A href="glossary.html#pathMTU">
+ path MTU discovery</A>. Since IPsec processing adds headers, enlarges
+ packets and may cause fragmentation, an IPsec gateway should be able to
+ send and receive these ICMP messages<STRONG> on both inside and outside
+ interfaces</STRONG>.</DD>
+</DL>
+<H3><A name="traceroute">UDP packets for traceroute</A></H3>
+<P>The traceroute(1) utility uses UDP port numbers from 33434 to
+ approximately 33633. Generally, these should be allowed through for
+ troubleshooting.</P>
+<P>Some firewalls drop these packets to prevent outsiders exploring the
+ protected network with traceroute(1). If that is your policy, consider
+ creating an exception for such packets arriving via an IPsec tunnel, at
+ least during intial testing of those tunnels.</P>
+<H3><A name="l2tp">UDP for L2TP</A></H3>
+<P> Windows 2000 does, and products designed for compatibility with it
+ may, build<A href="glossary.html#L2TP"> L2TP</A> tunnels over IPsec
+ connections.</P>
+<P>For this to work, you must allow UDP protocol 1701 packets coming out
+ of your tunnels to continue to their destination. You can, and probably
+ should, block such packets to or from your external interfaces, but
+ allow them from<VAR> ipsec0</VAR>.</P>
+<P>See also our Windows 2000<A href="interop.html#win2k"> interoperation
+ discussion</A>.</P>
+<H2><A name="packets">How it all works: IPsec packet details</A></H2>
+<P>IPsec uses three main types of packet:</P>
+<DL>
+<DT><A href="glossary.html#IKE">IKE</A> uses<STRONG> the UDP protocol
+ and port 500</STRONG>.</DT>
+<DD>Unless you are using only (less secure, not recommended) manual
+ keying, you need IKE to negotiate connection parameters, acceptable
+ algorithms, key sizes and key setup. IKE handles everything required to
+ set up, rekey, repair or tear down IPsec connections.</DD>
+<DT><A href="glossary.html#ESP">ESP</A> is<STRONG> protocol number 50</STRONG>
+</DT>
+<DD>This is required for encrypted connections.</DD>
+<DT><A href="glossary.html#AH">AH</A> is<STRONG> protocol number 51</STRONG>
+</DT>
+<DD>This can be used where only authentication, not encryption, is
+ required.</DD>
+</DL>
+<P>All of those packets should have appropriate IPsec gateway addresses
+ in both the to and from IP header fields. Firewall rules can check this
+ if you wish, though it is not strictly necessary. This is discussed in
+ more detail<A href="#unknowngate"> later</A>.</P>
+<P>IPsec processing of incoming packets authenticates them then removes
+ the ESP or AH header and decrypts if necessary. Successful processing
+ exposes an inner packet which is then delivered back to the firewall
+ machinery, marked as having arrived on an<VAR> ipsec[0-3]</VAR>
+ interface. Firewall rules can use that interface label to distinguish
+ these packets from unencrypted packets which are labelled with the
+ physical interface they arrived on (or perhaps with a non-IPsec virtual
+ interface such as<VAR> ppp0</VAR>).</P>
+<P>One of our users sent a mailing list message with a<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/12/msg00006.html">
+ diagram</A> of the packet flow.</P>
+<H3><A name="noport">ESP and AH do not have ports</A></H3>
+<P>Some protocols, such as TCP and UDP, have the notion of ports. Others
+ protocols, including ESP and AH, do not. Quite a few IPsec newcomers
+ have become confused on this point. There are no ports<EM> in</EM> the
+ ESP or AH protocols, and no ports used<EM> for</EM> them. For these
+ protocols,<EM> the idea of ports is completely irrelevant</EM>.</P>
+<H3><A name="header">Header layout</A></H3>
+<P>The protocol numbers for ESP or AH are used in the 'next header'
+ field of the IP header. On most non-IPsec packets, that field would
+ have one of:</P>
+<UL>
+<LI>1 for ICMP</LI>
+<LI>4 for IP-in-IP encapsulation</LI>
+<LI>6 for TCP</LI>
+<LI>17 for UDP</LI>
+<LI>... or one of about 100 other possibilities listed by<A href="http://www.iana.org">
+ IANA</A></LI>
+</UL>
+<P>Each header in the sequence tells what the next header will be. IPsec
+ adds headers for ESP or AH near the beginning of the sequence. The
+ original headers are kept and the 'next header' fields adjusted so that
+ all headers can be correctly interpreted.</P>
+<P>For example, using<STRONG> [</STRONG><STRONG> ]</STRONG> to indicate
+ data protected by ESP and unintelligible to an eavesdropper between the
+ gateways:</P>
+<UL>
+<LI>a simple packet might have only IP and TCP headers with:
+<UL>
+<LI>IP header says next header --&gt; TCP</LI>
+<LI>TCP header port number --&gt; which process to send data to</LI>
+<LI>data</LI>
+</UL>
+</LI>
+<LI>with ESP<A href="glossary.html#transport"> transport mode</A>
+ encapsulation, that packet would have:
+<UL>
+<LI>IP header says next header --&gt; ESP</LI>
+<LI>ESP header<STRONG> [</STRONG> says next --&gt; TCP</LI>
+<LI>TCP header port number --&gt; which process to send data to</LI>
+<LI>data<STRONG> ]</STRONG></LI>
+</UL>
+ Note that the IP header is outside ESP protection, visible to an
+ attacker, and that the final destination must be the gateway.</LI>
+<LI>with ESP in<A href="glossary.html#tunnel"> tunnel mode</A>, we might
+ have:
+<UL>
+<LI>IP header says next header --&gt; ESP</LI>
+<LI>ESP header<STRONG> [</STRONG> says next --&gt; IP</LI>
+<LI>IP header says next header --&gt; TCP</LI>
+<LI>TCP header port number --&gt; which process to send data to</LI>
+<LI>data<STRONG> ]</STRONG></LI>
+</UL>
+ Here the inner IP header is protected by ESP, unreadable by an
+ attacker. Also, the inner header can have a different IP address than
+ the outer IP header, so the decrypted packet can be routed from the
+ IPsec gateway to a final destination which may be another machine.</LI>
+</UL>
+<P>Part of the ESP header itself is encrypted, which is why the<STRONG>
+ [</STRONG> indicating protected data appears in the middle of some
+ lines above. The next header field of the ESP header is protected. This
+ makes<A href="glossary.html#traffic"> traffic analysis</A> more
+ difficult. The next header field would tell an eavesdropper whether
+ your packet was UDP to the gateway, TCP to the gateway, or encapsulated
+ IP. It is better not to give this information away. A clever attacker
+ may deduce some of it from the pattern of packet sizes and timings, but
+ we need not make it easy.</P>
+<P>IPsec allows various combinations of these to match local policies,
+ including combinations that use both AH and ESP headers or that nest
+ multiple copies of these headers.</P>
+<P>For example, suppose my employer has an IPsec VPN running between two
+ offices so all packets travelling between the gateways for those
+ offices are encrypted. If gateway policies allow it (The admins could
+ block UDP 500 and protocols 50 and 51 to disallow it), I can build an
+ IPsec tunnel from my desktop to a machine in some remote office. Those
+ packets will have one ESP header throughout their life, for my
+ end-to-end tunnel. For part of the route, however, they will also have
+ another ESP layer for the corporate VPN's encapsulation. The whole
+ header scheme for a packet on the Internet might be:</P>
+<UL>
+<LI>IP header (with gateway address) says next header --&gt; ESP</LI>
+<LI>ESP header<STRONG> [</STRONG> says next --&gt; IP</LI>
+<LI>IP header (with receiving machine address) says next header --&gt; ESP</LI>
+<LI>ESP header<STRONG> [</STRONG> says next --&gt; TCP</LI>
+<LI>TCP header port number --&gt; which process to send data to</LI>
+<LI>data<STRONG> ]]</STRONG></LI>
+</UL>
+<P>The first ESP (outermost) header is for the corporate VPN. The inner
+ ESP header is for the secure machine-to-machine link.</P>
+<H3><A name="dhr">DHR on the updown script</A></H3>
+<P>Here are some mailing list comments from<A href="manpage.d/ipsec_pluto.8.html">
+ pluto(8)</A> developer Hugh Redelmeier on an earlier draft of this
+ document:</P>
+<PRE>There are many important things left out
+
+- firewalling is important but must reflect (implement) policy.  Since
+  policy isn't the same for all our customers, and we're not experts,
+  we should concentrate on FW and MASQ interactions with FreeS/WAN.
+
+- we need a diagram to show packet flow WITHIN ONE MACHINE, assuming
+  IKE, IPsec, FW, and MASQ are all done on that machine.  The flow is
+  obvious if the components are run on different machines (trace the
+  cables).
+
+  IKE input:
+        + packet appears on public IF, as UDP port 500
+        + input firewalling rules are applied (may discard)
+        + Pluto sees the packet.
+
+  IKE output:
+        + Pluto generates the packet &amp; writes to public IF, UDP port 500
+        + output firewalling rules are applied (may discard)
+        + packet sent out public IF
+
+  IPsec input, with encapsulated packet, outer destination of this host:
+        + packet appears on public IF, protocol 50 or 51.  If this
+          packet is the result of decapsulation, it will appear
+          instead on the paired ipsec IF.
+        + input firewalling rules are applied (but packet is opaque)
+        + KLIPS decapsulates it, writes result to paired ipsec IF
+        + input firewalling rules are applied to resulting packet
+          as input on ipsec IF
+        + if the destination of the packet is this machine, the
+          packet is passed on to the appropriate protocol handler.
+          If the original packet was encapsulated more than once
+          and the new outer destination is this machine, that
+          handler will be KLIPS.
+        + otherwise:
+          * routing is done for the resulting packet.  This may well
+            direct it into KLIPS for encoding or encrypting.  What
+            happens then is described elsewhere.
+          * forwarding firewalling rules are applied
+          * output firewalling rules are applied
+          * the packet is sent where routing specified
+
+ IPsec input, with encapsulated packet, outer destination of another host:
+        + packet appears on some IF, protocol 50 or 51
+        + input firewalling rules are applied (but packet is opaque)
+        + routing selects where to send the packet
+        + forwarding firewalling rules are applied (but packet is opaque)
+        + packet forwarded, still encapsulated
+
+  IPsec output, from this host or from a client:
+        + if from a client, input firewalling rules are applied as the
+          packet arrives on the private IF
+        + routing directs the packet to an ipsec IF (this is how the
+          system decides KLIPS processing is required)
+        + if from a client, forwarding firewalling rules are applied
+        + KLIPS eroute mechanism matches the source and destination
+          to registered eroutes, yielding a SPI group.  This dictates
+          processing, and where the resulting packet is to be sent
+          (the destinations SG and the nexthop).
+        + output firewalling is not applied to the resulting
+          encapsulated packet
+
+- Until quite recently, KLIPS would double encapsulate packets that
+  didn't strictly need to be.  Firewalling should be prepared for
+  those packets showing up as ESP and AH protocol input packets on
+  an ipsec IF.
+
+- MASQ processing seems to be done as if it were part of the
+  forwarding firewall processing (this should be verified).
+
+- If a firewall is being used, it is likely the case that it needs to
+  be adjusted whenever IPsec SAs are added or removed.  Pluto invokes
+  a script to do this (and to adjust routing) at suitable times.  The
+  default script is only suitable for ipfwadm-managed firewalls.  Under
+  LINUX 2.2.x kernels, ipchains can be managed by ipfwadm (emulation),
+  but ipchains more powerful if manipulated using the ipchains command.
+  In this case, a custom updown script must be used.
+
+  We think that the flexibility of ipchains precludes us supplying an
+  updown script that would be widely appropriate.</PRE>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="manpages.html">Previous</A>
+<A HREF="trouble.html">Next</A>
+</BODY>
+</HTML>
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+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
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+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="web.html">Previous</A>
+<A HREF="biblio.html">Next</A>
+<HR>
+<H1><A name="ourgloss">Glossary for the Linux FreeS/WAN project</A></H1>
+<P>Entries are in alphabetical order. Some entries are only one line or
+ one paragraph long. Others run to several paragraphs. I have tried to
+ put the essential information in the first paragraph so you can skip
+ the other paragraphs if that seems appropriate.</P>
+<HR>
+<H2><A name="jump">Jump to a letter in the glossary</A></H2>
+<CENTER> <BIG><B><A href="#0">numeric</A><A href="#A"> A</A><A href="#B">
+ B</A><A href="#C"> C</A><A href="#D"> D</A><A href="#E"> E</A><A href="#F">
+ F</A><A href="#G"> G</A><A href="#H"> H</A><A href="#I"> I</A><A href="#J">
+ J</A><A href="#K"> K</A><A href="#L"> L</A><A href="#M"> M</A><A href="#N">
+ N</A><A href="#O"> O</A><A href="#P"> P</A><A href="#Q"> Q</A><A href="#R">
+ R</A><A href="#S"> S</A><A href="#T"> T</A><A href="#U"> U</A><A href="#V">
+ V</A><A href="#W"> W</A><A href="#X"> X</A><A href="#Y"> Y</A><A href="#Z">
+ Z</A></B></BIG></CENTER>
+<HR>
+<H2><A name="gloss">Other glossaries</A></H2>
+<P>Other glossaries which overlap this one include:</P>
+<UL>
+<LI>The VPN Consortium's glossary of<A href="http://www.vpnc.org/terms.html">
+ VPN terms</A>.</LI>
+<LI>glossary portion of the<A href="http://www.rsa.com/rsalabs/faq/B.html">
+ Cryptography FAQ</A></LI>
+<LI>an extensive crytographic glossary on<A href="http://www.ciphersbyritter.com/GLOSSARY.HTM">
+ Terry Ritter's</A> page.</LI>
+<LI>The<A href="#NSA"> NSA</A>'s<A href="http://www.sans.org/newlook/resources/glossary.htm">
+ glossary of computer security</A> on the<A href="http://www.sans.org">
+ SANS Institute</A> site.</LI>
+<LI>a small glossary for Internet Security at<A href="http://www5.zdnet.com/pcmag/pctech/content/special/glossaries/internetsecurity.html">
+ PC magazine</A></LI>
+<LI>The<A href="http://www.visi.com/crypto/inet-crypto/glossary.html">
+ glossary</A> from Richard Smith's book<A href="biblio.html#Smith">
+ Internet Cryptography</A></LI>
+</UL>
+<P>Several Internet glossaries are available as RFCs:</P>
+<UL>
+<LI><A href="http://www.rfc-editor.org/rfc/rfc1208.txt">Glossary of
+ Networking Terms</A></LI>
+<LI><A href="http://www.rfc-editor.org/rfc/rfc1983.txt">Internet User's
+ Glossary</A></LI>
+<LI><A href="http://www.rfc-editor.org/rfc/rfc2828.txt">Internet
+ Security Glossary</A></LI>
+</UL>
+<P>More general glossary or dictionary information:</P>
+<UL>
+<LI>Free Online Dictionary of Computing (FOLDOC)
+<UL>
+<LI><A href="http://www.nightflight.com/foldoc">North America</A></LI>
+<LI><A href="http://wombat.doc.ic.ac.uk/foldoc/index.html">Europe</A></LI>
+<LI><A href="http://www.nue.org/foldoc/index.html">Japan</A></LI>
+</UL>
+<P>There are many more mirrors of this dictionary.</P>
+</LI>
+<LI>The Jargon File, the definitive resource for hacker slang and
+ folklore
+<UL>
+<LI><A href="http://www.netmeg.net/jargon">North America</A></LI>
+<LI><A href="http://info.wins.uva.nl/~mes/jargon/">Holland</A></LI>
+<LI><A href="http://www.tuxedo.org/~esr/jargon">home page</A></LI>
+</UL>
+<P>There are also many mirrors of this. See the home page for a list.</P>
+</LI>
+<LI>A general<A href="http://www.trinity.edu/~rjensen/245glosf.htm#Navigate">
+ technology glossary</A></LI>
+<LI>An<A href="http://www.yourdictionary.com/"> online dictionary
+ resource page</A> with pointers to many dictionaries for many languages</LI>
+<LI>A<A href="http://www.onelook.com/"> search engine</A> that accesses
+ several hundred online dictionaries</LI>
+<LI>O'Reilly<A href="http://www.ora.com/reference/dictionary/">
+ Dictionary of PC Hardware and Data Communications Terms</A></LI>
+<LI><A href="http://www.FreeSoft.org/CIE/index.htm">Connected</A>
+ Internet encyclopedia</LI>
+<LI><A href="http://www.whatis.com/">whatis.com</A></LI>
+</UL>
+<HR>
+<H2><A name="definitions">Definitions</A></H2>
+<DL>
+<DT><A name="0">0</A></DT>
+<DT><A name="3DES">3DES (Triple DES)</A></DT>
+<DD>Using three<A href="#DES"> DES</A> encryptions on a single data
+ block, with at least two different keys, to get higher security than is
+ available from a single DES pass. The three-key version of 3DES is the
+ default encryption algorithm for<A href="web.html#FreeSWAN"> Linux
+ FreeS/WAN</A>.
+<P><A href="#IPSEC">IPsec</A> always does 3DES with three different
+ keys, as required by RFC 2451. For an explanation of the two-key
+ variant, see<A href="#2key"> two key triple DES</A>. Both use an<A href="#EDE">
+ EDE</A> encrypt-decrypt-encrpyt sequence of operations.</P>
+<P>Single<A href="#DES"> DES</A> is<A href="politics.html#desnotsecure">
+ insecure</A>.</P>
+<P>Double DES is ineffective. Using two 56-bit keys, one might expect an
+ attacker to have to do 2<SUP>112</SUP> work to break it. In fact, only
+ 2<SUP>57</SUP> work is required with a<A href="#meet">
+ meet-in-the-middle attack</A>, though a large amount of memory is also
+ required. Triple DES is vulnerable to a similar attack, but that just
+ reduces the work factor from the 2<SUP>168</SUP> one might expect to 2<SUP>
+112</SUP>. That provides adequate protection against<A href="#brute">
+ brute force</A> attacks, and no better attack is known.</P>
+<P>3DES can be somewhat slow compared to other ciphers. It requires
+ three DES encryptions per block. DES was designed for hardware
+ implementation and includes some operations which are difficult in
+ software. However, the speed we get is quite acceptable for many uses.
+ See our<A href="performance.html"> performance</A> document for
+ details.</P>
+</DD>
+<DT><A name="A">A</A></DT>
+<DT><A name="active">Active attack</A></DT>
+<DD>An attack in which the attacker does not merely eavesdrop (see<A href="#passive">
+ passive attack</A>) but takes action to change, delete, reroute, add,
+ forge or divert data. Perhaps the best-known active attack is<A href="#middle">
+ man-in-the-middle</A>. In general,<A href="#authentication">
+ authentication</A> is a useful defense against active attacks.</DD>
+<DT><A name="AES">AES</A></DT>
+<DD>The<B> A</B>dvanced<B> E</B>ncryption<B> S</B>tandard -- a new<A href="#block">
+ block cipher</A> standard to replace<A href="politics.html#desnotsecure">
+ DES</A> -- developed by<A href="#NIST"> NIST</A>, the US National
+ Institute of Standards and Technology. DES used 64-bit blocks and a
+ 56-bit key. AES ciphers use a 128-bit block and 128, 192 or 256-bit
+ keys. The larger block size helps resist<A href="#birthday"> birthday
+ attacks</A> while the large key size prevents<A href="#brute"> brute
+ force attacks</A>.
+<P>Fifteen proposals meeting NIST's basic criteria were submitted in
+ 1998 and subjected to intense discussion and analysis, &quot;round one&quot;
+ evaluation. In August 1999, NIST narrowed the field to five &quot;round two&quot;
+ candidates:</P>
+<UL>
+<LI><A href="http://www.research.ibm.com/security/mars.html">Mars</A>
+ from IBM</LI>
+<LI><A href="http://www.rsa.com/rsalabs/aes/">RC6</A> from RSA</LI>
+<LI><A href="http://www.esat.kuleuven.ac.be/~rijmen/rijndael/">Rijndael</A>
+ from two Belgian researchers</LI>
+<LI><A href="http://www.cl.cam.ac.uk/~rja14/serpent.html">Serpent</A>, a
+ British-Norwegian-Israeli collaboration</LI>
+<LI><A href="http://www.counterpane.com/twofish.html">Twofish</A> from
+ the consulting firm<A href="http://www.counterpane.com"> Counterpane</A>
+</LI>
+</UL>
+<P>Three of the five finalists -- Rijndael, Serpent and Twofish -- have
+ completely open licenses.</P>
+<P>In October 2000, NIST announced the winner -- Rijndael.</P>
+<P>For more information, see:</P>
+<UL>
+<LI>NIST's<A href="http://csrc.nist.gov/encryption/aes/aes_home.htm">
+ AES home page</A></LI>
+<LI>the Block Cipher Lounge<A href="http://www.ii.uib.no/~larsr/aes.html">
+ AES page</A></LI>
+<LI>Brian Gladman's<A href="http://fp.gladman.plus.com/cryptography_technology/index.htm">
+ code and benchmarks</A></LI>
+<LI>Helger Lipmaa's<A href="http://www.tcs.hut.fi/~helger/aes/"> survey
+ of implementations</A></LI>
+</UL>
+<P>AES will be added to a future release of<A href="web.html#FreeSWAN">
+ Linux FreeS/WAN</A>. Likely we will add all three of the finalists with
+ good licenses. User-written<A href="web.html#patch"> AES patches</A>
+ are already available.</P>
+<P>Adding AES may also require adding stronger hashes,<A href="#SHA-256">
+ SHA-256, SHA-384 and SHA-512</A>.</P>
+</DD>
+<DT><A name="AH">AH</A></DT>
+<DD>The<A href="#IPSEC"> IPsec</A><B> A</B>uthentication<B> H</B>eader,
+ added after the IP header. For details, see our<A href="ipsec.html#AH.ipsec">
+ IPsec</A> document and/or RFC 2402.</DD>
+<DT><A name="alicebob">Alice and Bob</A></DT>
+<DD>A and B, the standard example users in writing on cryptography and
+ coding theory. Carol and Dave join them for protocols which require
+ more players.
+<P>Bruce Schneier extends these with many others such as Eve the
+ Eavesdropper and Victor the Verifier. His extensions seem to be in the
+ process of becoming standard as well. See page 23 of<A href="biblio.html#schneier">
+ Applied Cryptography</A></P>
+<P>Alice and Bob have an amusing<A href="http://www.conceptlabs.co.uk/alicebob.html">
+ biography</A> on the web.</P>
+</DD>
+<DT>ARPA</DT>
+<DD>see<A href="#DARPA"> DARPA</A></DD>
+<DT><A name="ASIO">ASIO</A></DT>
+<DD>Australian Security Intelligence Organisation.</DD>
+<DT>Asymmetric cryptography</DT>
+<DD>See<A href="#public"> public key cryptography</A>.</DD>
+<DT><A name="authentication">Authentication</A></DT>
+<DD>Ensuring that a message originated from the expected sender and has
+ not been altered on route.<A href="#IPSEC"> IPsec</A> uses
+ authentication in two places:
+<UL>
+<LI>peer authentication, authenticating the players in<A href="#IKE">
+ IKE</A>'s<A href="#DH"> Diffie-Hellman</A> key exchanges to prevent<A href="#middle">
+ man-in-the-middle attacks</A>. This can be done in a number of ways.
+ The methods supported by FreeS/WAN are discussed in our<A href="adv_config.html#choose">
+ advanced configuration</A> document.</LI>
+<LI>packet authentication, authenticating packets on an established<A href="#SA">
+ SA</A>, either with a separate<A href="#AH"> authentication header</A>
+ or with the optional authentication in the<A href="#ESP"> ESP</A>
+ protocol. In either case, packet authentication uses a<A href="#HMAC">
+ hashed message athentication code</A> technique.</LI>
+</UL>
+<P>Outside IPsec, passwords are perhaps the most common authentication
+ mechanism. Their function is essentially to authenticate the person's
+ identity to the system. Passwords are generally only as secure as the
+ network they travel over. If you send a cleartext password over a
+ tapped phone line or over a network with a packet sniffer on it, the
+ security provided by that password becomes zero. Sending an encrypted
+ password is no better; the attacker merely records it and reuses it at
+ his convenience. This is called a<A href="#replay"> replay</A> attack.</P>
+<P>A common solution to this problem is a<A href="#challenge">
+ challenge-response</A> system. This defeats simple eavesdropping and
+ replay attacks. Of course an attacker might still try to break the
+ cryptographic algorithm used, or the<A href="#random"> random number</A>
+ generator.</P>
+</DD>
+<DT><A name="auto">Automatic keying</A></DT>
+<DD>A mode in which keys are automatically generated at connection
+ establisment and new keys automaically created periodically thereafter.
+ Contrast with<A href="ipsec.html#manual"> manual keying</A> in which a
+ single stored key is used.
+<P>IPsec uses the<A href="#DH"> Diffie-Hellman key exchange protocol</A>
+ to create keys. An<A href="#authentication"> authentication</A>
+ mechansim is required for this. FreeS/WAN normally uses<A href="#RSA">
+ RSA</A> for this. Other methods supported are discussed in our<A href="adv_config.html#choose">
+ advanced configuration</A> document.</P>
+<P>Having an attacker break the authentication is emphatically not a
+ good idea. An attacker that breaks authentication, and manages to
+ subvert some other network entities (DNS, routers or gateways), can use
+ a<A href="#middle"> man-in-the middle attack</A> to break the security
+ of your IPsec connections.</P>
+<P>However, having an attacker break the authentication in automatic
+ keying is not quite as bad as losing the key in manual keying.</P>
+<UL>
+<LI>An attacker who reads /etc/ipsec.conf and gets the keys for a
+ manually keyed connection can, without further effort, read all
+ messages encrypted with those keys, including any old messages he may
+ have archived.</LI>
+<LI>Automatic keying has a property called<A href="#PFS"> perfect
+ forward secrecy</A>. An attacker who breaks the authentication gets
+ none of the automatically generated keys and cannot immediately read
+ any messages. He has to mount a successful<A href="#middle">
+ man-in-the-middle attack</A> in real time before he can read anything.
+ He cannot read old archived messages at all and will not be able to
+ read any future messages not caught by man-in-the-middle tricks.</LI>
+</UL>
+<P>That said, the secrets used for authentication, stored in<A href="manpage.d/ipsec.secrets.5.html">
+ ipsec.secrets(5)</A>, should still be protected as tightly as
+ cryptographic keys.</P>
+</DD>
+<DT><A name="B">B</A></DT>
+<DT><A href="http://www.nortelnetworks.com">Bay Networks</A></DT>
+<DD>A vendor of routers, hubs and related products, now a subsidiary of
+ Nortel. Interoperation between their IPsec products and Linux FreeS/WAN
+ was problematic at last report; see our<A href="interop.html#bay">
+ interoperation</A> section.</DD>
+<DT><A name="benchmarks">benchmarks</A></DT>
+<DD>Our default block cipher,<A href="#3DES"> triple DES</A>, is slower
+ than many alternate ciphers that might be used. Speeds achieved,
+ however, seem adequate for many purposes. For example, the assembler
+ code from the<A href="#LIBDES"> LIBDES</A> library we use encrypts 1.6
+ megabytes per second on a Pentium 200, according to the test program
+ supplied with the library.
+<P>For more detail, see our document on<A href="performance.html">
+ FreeS/WAN performance</A>.</P>
+</DD>
+<DT><A name="BIND">BIND</A></DT>
+<DD><B>B</B>erkeley<B> I</B>nternet<B> N</B>ame<B> D</B>aemon, a widely
+ used implementation of<A href="ipsec.html#DNS"> DNS</A> (Domain Name
+ Service). See our bibliography for a<A href="ipsec.html#DNS"> useful
+ reference</A>. See the<A href="http://www.isc.org/bind.html"> BIND home
+ page</A> for more information and the latest version.</DD>
+<DT><A name="birthday">Birthday attack</A></DT>
+<DD>A cryptographic attack based on the mathematics exemplified by the<A href="#paradox">
+ birthday paradox</A>. This math turns up whenever the question of two
+ cryptographic operations producing the same result becomes an issue:
+<UL>
+<LI><A href="#collision">collisions</A> in<A href="#digest"> message
+ digest</A> functions.</LI>
+<LI>identical output blocks from a<A href="#block"> block cipher</A></LI>
+<LI>repetition of a challenge in a<A href="#challenge">
+ challenge-response</A> system</LI>
+</UL>
+<P>Resisting such attacks is part of the motivation for:</P>
+<UL>
+<LI>hash algorithms such as<A href="#SHA"> SHA</A> and<A href="#RIPEMD">
+ RIPEMD-160</A> giving a 160-bit result rather than the 128 bits of<A href="#MD4">
+ MD4</A>,<A href="#MD5"> MD5</A> and<A href="#RIPEMD"> RIPEMD-128</A>.</LI>
+<LI><A href="#AES">AES</A> block ciphers using a 128-bit block instead
+ of the 64-bit block of most current ciphers</LI>
+<LI><A href="#IPSEC">IPsec</A> using a 32-bit counter for packets sent
+ on an<A href="ipsec.html#auto"> automatically keyed</A><A href="#SA">
+ SA</A> and requiring that the connection always be rekeyed before the
+ counter overflows.</LI>
+</UL>
+</DD>
+<DT><A name="paradox">Birthday paradox</A></DT>
+<DD>Not really a paradox, just a rather counter-intuitive mathematical
+ fact. In a group of 23 people, the chance of a least one pair having
+ the same birthday is over 50%.
+<P>The second person has 1 chance in 365 (ignoring leap years) of
+ matching the first. If they don't match, the third person's chances of
+ matching one of them are 2/365. The 4th, 3/365, and so on. The total of
+ these chances grows more quickly than one might guess.</P>
+</DD>
+<DT><A name="block">Block cipher</A></DT>
+<DD>A<A href="#symmetric"> symmetric cipher</A> which operates on
+ fixed-size blocks of plaintext, giving a block of ciphertext for each.
+ Contrast with<A href="#stream"> stream cipher</A>. Block ciphers can be
+ used in various<A href="#mode"> modes</A> when multiple block are to be
+ encrypted.
+<P><A href="#DES">DES</A> is among the the best known and widely used
+ block ciphers, but is now obsolete. Its 56-bit key size makes it<A href="politics.html#desnotsecure">
+ highly insecure</A> today.<A href="#3DES"> Triple DES</A> is the
+ default block cipher for<A href="web.html#FreeSWAN"> Linux FreeS/WAN</A>
+.</P>
+<P>The current generation of block ciphers -- such as<A href="#Blowfish">
+ Blowfish</A>,<A href="#CAST128"> CAST-128</A> and<A href="#IDEA"> IDEA</A>
+ -- all use 64-bit blocks and 128-bit keys. The next generation,<A href="#AES">
+ AES</A>, uses 128-bit blocks and supports key sizes up to 256 bits.</P>
+<P>The<A href="http://www.ii.uib.no/~larsr/bc.html"> Block Cipher Lounge</A>
+ web site has more information.</P>
+</DD>
+<DT><A name="Blowfish">Blowfish</A></DT>
+<DD>A<A href="#block"> block cipher</A> using 64-bit blocks and keys of
+ up to 448 bits, designed by<A href="biblio.html#schneier"> Bruce
+ Schneier</A> and used in several products.
+<P>This is not required by the<A href="#IPSEC"> IPsec</A> RFCs and not
+ currently used in<A href="web.html#FreeSWAN"> Linux FreeS/WAN</A>.</P>
+</DD>
+<DT><A name="brute">Brute force attack (exhaustive search)</A></DT>
+<DD>Breaking a cipher by trying all possible keys. This is always
+ possible in theory (except against a<A href="#OTP"> one-time pad</A>),
+ but it becomes practical only if the key size is inadequate. For an
+ important example, see our document on the<A href="politics.html#desnotsecure">
+ insecurity of DES</A> with its 56-bit key. For an analysis of key sizes
+ required to resist plausible brute force attacks, see<A href="http://www.counterpane.com/keylength.html">
+ this paper</A>.
+<P>Longer keys protect against brute force attacks. Each extra bit in
+ the key doubles the number of possible keys and therefore doubles the
+ work a brute force attack must do. A large enough key defeats<STRONG>
+ any</STRONG> brute force attack.</P>
+<P>For example, the EFF's<A href="#EFF"> DES Cracker</A> searches a
+ 56-bit key space in an average of a few days. Let us assume an attacker
+ that can find a 64-bit key (256 times harder) by brute force search in
+ a second (a few hundred thousand times faster). For a 96-bit key, that
+ attacker needs 2<SUP>32</SUP> seconds, about 135 years. Against a
+ 128-bit key, he needs 2<SUP>32</SUP> times that, over 500,000,000,000
+ years. Your data is then obviously secure against brute force attacks.
+ Even if our estimate of the attacker's speed is off by a factor of a
+ million, it still takes him over 500,000 years to crack a message.</P>
+<P>This is why</P>
+<UL>
+<LI>single<A href="#DES"> DES</A> is now considered<A href="politics.html#desnotsecure">
+ dangerously insecure</A></LI>
+<LI>all of the current generation of<A href="#block"> block ciphers</A>
+ use a 128-bit or longer key</LI>
+<LI><A href="#AES">AES</A> ciphers support keysizes 128, 192 and 256
+ bits</LI>
+<LI>any cipher we add to Linux FreeS/WAN will have<EM> at least</EM> a
+ 128-bit key</LI>
+</UL>
+<P><STRONG>Cautions:</STRONG>
+<BR><EM> Inadequate keylength always indicates a weak cipher</EM> but it
+ is important to note that<EM> adequate keylength does not necessarily
+ indicate a strong cipher</EM>. There are many attacks other than brute
+ force, and adequate keylength<EM> only</EM> guarantees resistance to
+ brute force. Any cipher, whatever its key size, will be weak if design
+ or implementation flaws allow other attacks.</P>
+<P>Also,<EM> once you have adequate keylength</EM> (somewhere around 90
+ or 100 bits),<EM> adding more key bits make no practical difference</EM>
+, even against brute force. Consider our 128-bit example above that
+ takes 500,000,000,000 years to break by brute force. We really don't
+ care how many zeroes there are on the end of that, as long as the
+ number remains ridiculously large. That is, we don't care exactly how
+ large the key is as long as it is large enough.</P>
+<P>There may be reasons of convenience in the design of the cipher to
+ support larger keys. For example<A href="#Blowfish"> Blowfish</A>
+ allows up to 448 bits and<A href="#RC4"> RC4</A> up to 2048, but beyond
+ 100-odd bits it makes no difference to practical security.</P>
+</DD>
+<DT>Bureau of Export Administration</DT>
+<DD>see<A href="#BXA"> BXA</A></DD>
+<DT><A name="BXA">BXA</A></DT>
+<DD>The US Commerce Department's<B> B</B>ureau of E<B>x</B>port<B> A</B>
+dministration which administers the<A href="#EAR"> EAR</A> Export
+ Administration Regulations controling the export of, among other
+ things, cryptography.</DD>
+<DT><A name="C">C</A></DT>
+<DT><A name="CA">CA</A></DT>
+<DD><B>C</B>ertification<B> A</B>uthority, an entity in a<A href="#PKI">
+ public key infrastructure</A> that can certify keys by signing them.
+ Usually CAs form a hierarchy. The top of this hierarchy is called the<A href="#rootCA">
+ root CA</A>.
+<P>See<A href="#web"> Web of Trust</A> for an alternate model.</P>
+</DD>
+<DT><A name="CAST128">CAST-128</A></DT>
+<DD>A<A href="#block"> block cipher</A> using 64-bit blocks and 128-bit
+ keys, described in RFC 2144 and used in products such as<A href="#Entrust">
+ Entrust</A> and recent versions of<A href="#PGP"> PGP</A>.
+<P>This is not required by the<A href="#IPSEC"> IPsec</A> RFCs and not
+ currently used in<A href="web.html#FreeSWAN"> Linux FreeS/WAN</A>.</P>
+</DD>
+<DT>CAST-256</DT>
+<DD><A href="#Entrust">Entrust</A>'s candidate cipher for the<A href="#AES">
+ AES standard</A>, largely based on the<A href="#CAST128"> CAST-128</A>
+ design.</DD>
+<DT><A name="CBC">CBC mode</A></DT>
+<DD><B>C</B>ipher<B> B</B>lock<B> C</B>haining<A href="#mode"> mode</A>,
+ a method of using a<A href="#block"> block cipher</A> in which for each
+ block except the first, the result of the previous encryption is XORed
+ into the new block before it is encrypted. CBC is the mode used in<A href="#IPSEC">
+ IPsec</A>.
+<P>An<A href="#IV"> initialisation vector</A> (IV) must be provided. It
+ is XORed into the first block before encryption. The IV need not be
+ secret but should be different for each message and unpredictable.</P>
+</DD>
+<DT><A name="CIDR">CIDR</A></DT>
+<DD><B>C</B>lassless<B> I</B>nter-<B>D</B>omain<B> R</B>outing, an
+ addressing scheme used to describe networks not restricted to the old
+ Class A, B, and C sizes. A CIDR block is written<VAR> address</VAR>/<VAR>
+mask</VAR>, where<VAR> address</VAR> is a 32-bit Internet address. The
+ first<VAR> mask</VAR> bits of<VAR> address</VAR> are part of the
+ gateway address, while the remaining bits designate other host
+ addresses. For example, the CIDR block 192.0.2.96/27 describes a
+ network with gateway 192.0.2.96, hosts 192.0.2.96 through 192.0.2.126
+ and broadcast 192.0.2.127.
+<P>FreeS/WAN policy group files accept CIDR blocks of the format<VAR>
+ address</VAR>/[<VAR>mask</VAR>], where<VAR> address</VAR> may take the
+ form<VAR> name.domain.tld</VAR>. An absent<VAR> mask</VAR> is assumed
+ to be /32.</P>
+</DD>
+<DT>Certification Authority</DT>
+<DD>see<A href="#CA"> CA</A></DD>
+<DT><A name="challenge">Challenge-response authentication</A></DT>
+<DD>An<A href="#authentication"> authentication</A> system in which one
+ player generates a<A href="#random"> random number</A>, encrypts it and
+ sends the result as a challenge. The other player decrypts and sends
+ back the result. If the result is correct, that proves to the first
+ player that the second player knew the appropriate secret, required for
+ the decryption. Variations on this technique exist using<A href="#public">
+ public key</A> or<A href="#symmetric"> symmetric</A> cryptography. Some
+ provide two-way authentication, assuring each player of the other's
+ identity.
+<P>This is more secure than passwords against two simple attacks:</P>
+<UL>
+<LI>If cleartext passwords are sent across the wire (e.g. for telnet),
+ an eavesdropper can grab them. The attacker may even be able to break
+ into other systems if the user has chosen the same password for them.</LI>
+<LI>If an encrypted password is sent, an attacker can record the
+ encrypted form and use it later. This is called a replay attack.</LI>
+</UL>
+<P>A challenge-response system never sends a password, either cleartext
+ or encrypted. An attacker cannot record the response to one challenge
+ and use it as a response to a later challenge. The random number is
+ different each time.</P>
+<P>Of course an attacker might still try to break the cryptographic
+ algorithm used, or the<A href="#random"> random number</A> generator.</P>
+</DD>
+<DT><A name="mode">Cipher Modes</A></DT>
+<DD>Different ways of using a block cipher when encrypting multiple
+ blocks.
+<P>Four standard modes were defined for<A href="#DES"> DES</A> in<A href="#FIPS">
+ FIPS</A> 81. They can actually be applied with any block cipher.</P>
+<TABLE><TBODY></TBODY>
+<TR><TD></TD><TD><A href="#ECB">ECB</A></TD><TD>Electronic CodeBook</TD><TD>
+encrypt each block independently</TD></TR>
+<TR><TD></TD><TD><A href="#CBC">CBC</A></TD><TD>Cipher Block Chaining
+<BR></TD><TD>XOR previous block ciphertext into new block plaintext
+ before encrypting new block</TD></TR>
+<TR><TD></TD><TD>CFB</TD><TD>Cipher FeedBack</TD><TD></TD></TR>
+<TR><TD></TD><TD>OFB</TD><TD>Output FeedBack</TD><TD></TD></TR>
+</TABLE>
+<P><A href="#IPSEC">IPsec</A> uses<A href="#CBC"> CBC</A> mode since
+ this is only marginally slower than<A href="#ECB"> ECB</A> and is more
+ secure. In ECB mode the same plaintext always encrypts to the same
+ ciphertext, unless the key is changed. In CBC mode, this does not
+ occur.</P>
+<P>Various other modes are also possible, but none of them are used in
+ IPsec.</P>
+</DD>
+<DT><A name="ciphertext">Ciphertext</A></DT>
+<DD>The encrypted output of a cipher, as opposed to the unencrypted<A href="#plaintext">
+ plaintext</A> input.</DD>
+<DT><A href="http://www.cisco.com">Cisco</A></DT>
+<DD>A vendor of routers, hubs and related products. Their IPsec products
+ interoperate with Linux FreeS/WAN; see our<A href="interop.html#Cisco">
+ interop</A> section.</DD>
+<DT><A name="client">Client</A></DT>
+<DD>This term has at least two distinct uses in discussing IPsec:
+<UL>
+<LI>The<STRONG> clients of an IPsec gateway</STRONG> are the machines it
+ protects, typically on one or more subnets behind the gateway. In this
+ usage, all the machines on an office network are clients of that
+ office's IPsec gateway. Laptop or home machines connecting to the
+ office, however, are<EM> not</EM> clients of that gateway. They are
+ remote gateways, running the other end of an IPsec connection. Each of
+ them is also its own client.</LI>
+<LI><STRONG>IPsec client software</STRONG> is used to describe software
+ which runs on various standalone machines to let them connect to IPsec
+ networks. In this usage, a laptop or home machine connecting to the
+ office is a client, and the office gateway is the server.</LI>
+</UL>
+<P>We generally use the term in the first sense. Vendors of Windows
+ IPsec solutions often use it in the second. See this<A href="interop.html#client.server">
+ discussion</A>.</P>
+</DD>
+<DT><A name="cc">Common Criteria</A></DT>
+<DD>A set of international security classifications which are replacing
+ the old US<A href="#rainbow"> Rainbow Book</A> standards and similar
+ standards in other countries.
+<P>Web references include this<A href="http://csrc.nist.gov/cc"> US
+ government site</A> and this<A href="http://www.commoncriteria.org">
+ global home page</A>.</P>
+</DD>
+<DT>Conventional cryptography</DT>
+<DD>See<A href="#symmetric"> symmetric cryptography</A></DD>
+<DT><A name="collision">Collision resistance</A></DT>
+<DD>The property of a<A href="#digest"> message digest</A> algorithm
+ which makes it hard for an attacker to find or construct two inputs
+ which hash to the same output.</DD>
+<DT>Copyleft</DT>
+<DD>see GNU<A href="#GPL"> General Public License</A></DD>
+<DT><A name="CSE">CSE</A></DT>
+<DD><A href="http://www.cse-cst.gc.ca/">Communications Security
+ Establishment</A>, the Canadian organisation for<A href="#SIGINT">
+ signals intelligence</A>.</DD>
+<DT><A name="D">D</A></DT>
+<DT><A name="DARPA">DARPA (sometimes just ARPA)</A></DT>
+<DD>The US government's<B> D</B>efense<B> A</B>dvanced<B> R</B>esearch<B>
+ P</B>rojects<B> A</B>gency. Projects they have funded over the years
+ have included the Arpanet which evolved into the Internet, the TCP/IP
+ protocol suite (as a replacement for the original Arpanet suite), the
+ Berkeley 4.x BSD Unix projects, and<A href="#SDNS"> Secure DNS</A>.
+<P>For current information, see their<A href="http://www.darpa.mil/ito">
+ web site</A>.</P>
+</DD>
+<DT><A name="DOS">Denial of service (DoS) attack</A></DT>
+<DD>An attack that aims at denying some service to legitimate users of a
+ system, rather than providing a service to the attacker.
+<UL>
+<LI>One variant is a flooding attack, overwhelming the system with too
+ many packets, to much email, or whatever.</LI>
+<LI>A closely related variant is a resource exhaustion attack. For
+ example, consider a &quot;TCP SYN flood&quot; attack. Setting up a TCP connection
+ involves a three-packet exchange:
+<UL>
+<LI>Initiator: Connection please (SYN)</LI>
+<LI>Responder: OK (ACK)</LI>
+<LI>Initiator: OK here too</LI>
+</UL>
+<P>If the attacker puts bogus source information in the first packet,
+ such that the second is never delivered, the responder may wait a long
+ time for the third to come back. If responder has already allocated
+ memory for the connection data structures, and if many of these bogus
+ packets arrive, the responder may run out of memory.</P>
+</LI>
+<LI>Another variant is to feed the system undigestible data, hoping to
+ make it sick. For example, IP packets are limited in size to 64K bytes
+ and a fragment carries information on where it starts within that 64K
+ and how long it is. The &quot;ping of death&quot; delivers fragments that say,
+ for example, that they start at 60K and are 20K long. Attempting to
+ re-assemble these without checking for overflow can be fatal.</LI>
+</UL>
+<P>The two example attacks discussed were both quite effective when
+ first discovered, capable of crashing or disabling many operating
+ systems. They were also well-publicised, and today far fewer systems
+ are vulnerable to them.</P>
+</DD>
+<DT><A name="DES">DES</A></DT>
+<DD>The<B> D</B>ata<B> E</B>ncryption<B> S</B>tandard, a<A href="#block">
+ block cipher</A> with 64-bit blocks and a 56-bit key. Probably the most
+ widely used<A href="#symmetric"> symmetric cipher</A> ever devised. DES
+ has been a US government standard for their own use (only for
+ unclassified data), and for some regulated industries such as banking,
+ since the late 70's. It is now being replaced by<A href="#AES"> AES</A>
+.
+<P><A href="politics.html#desnotsecure">DES is seriously insecure
+ against current attacks.</A></P>
+<P><A href="web.html#FreeSWAN">Linux FreeS/WAN</A> does not include DES,
+ even though the RFCs specify it.<B> We strongly recommend that single
+ DES not be used.</B></P>
+<P>See also<A href="#3DES"> 3DES</A> and<A href="#DESX"> DESX</A>,
+ stronger ciphers based on DES.</P>
+</DD>
+<DT><A name="DESX">DESX</A></DT>
+<DD>An improved<A href="#DES"> DES</A> suggested by Ron Rivest of RSA
+ Data Security. It XORs extra key material into the text before and
+ after applying the DES cipher.
+<P>This is not required by the<A href="#IPSEC"> IPsec</A> RFCs and not
+ currently used in<A href="web.html#FreeSWAN"> Linux FreeS/WAN</A>. DESX
+ would be the easiest additional transform to add; there would be very
+ little code to write. It would be much faster than 3DES and almost
+ certainly more secure than DES. However, since it is not in the RFCs
+ other IPsec implementations cannot be expected to have it.</P>
+</DD>
+<DT>DH</DT>
+<DD>see<A href="#DH"> Diffie-Hellman</A></DD>
+<DT><A name="DHCP">DHCP</A></DT>
+<DD><STRONG>D</STRONG>ynamic<STRONG> H</STRONG>ost<STRONG> C</STRONG>
+onfiguration<STRONG> P</STRONG>rotocol, a method of assigning<A href="#dynamic">
+ dynamic IP addresses</A>, and providing additional information such as
+ addresses of DNS servers and of gateways. See this<A href="http://www.dhcp.org">
+ DHCP resource page.</A></DD>
+<DT><A name="DH">Diffie-Hellman (DH) key exchange protocol</A></DT>
+<DD>A protocol that allows two parties without any initial shared secret
+ to create one in a manner immune to eavesdropping. Once they have done
+ this, they can communicate privately by using that shared secret as a
+ key for a block cipher or as the basis for key exchange.
+<P>The protocol is secure against all<A href="#passive"> passive attacks</A>
+, but it is not at all resistant to active<A href="#middle">
+ man-in-the-middle attacks</A>. If a third party can impersonate Bob to
+ Alice and vice versa, then no useful secret can be created.
+ Authentication of the participants is a prerequisite for safe
+ Diffie-Hellman key exchange. IPsec can use any of several<A href="#authentication">
+ authentication</A> mechanisims. Those supported by FreeS/WAN are
+ discussed in our<A href="config.html#choose"> configuration</A>
+ section.</P>
+<P>The Diffie-Hellman key exchange is based on the<A href="#dlog">
+ discrete logarithm</A> problem and is secure unless someone finds an
+ efficient solution to that problem.</P>
+<P>Given a prime<VAR> p</VAR> and generator<VAR> g</VAR> (explained
+ under<A href="#dlog"> discrete log</A> below), Alice:</P>
+<UL>
+<LI>generates a random number<VAR> a</VAR></LI>
+<LI>calculates<VAR> A = g^a modulo p</VAR></LI>
+<LI>sends<VAR> A</VAR> to Bob</LI>
+</UL>
+<P>Meanwhile Bob:</P>
+<UL>
+<LI>generates a random number<VAR> b</VAR></LI>
+<LI>calculates<VAR> B = g^b modulo p</VAR></LI>
+<LI>sends<VAR> B</VAR> to Alice</LI>
+</UL>
+<P>Now Alice and Bob can both calculate the shared secret<VAR> s =
+ g^(ab)</VAR>. Alice knows<VAR> a</VAR> and<VAR> B</VAR>, so she
+ calculates<VAR> s = B^a</VAR>. Bob knows<VAR> A</VAR> and<VAR> b</VAR>
+ so he calculates<VAR> s = A^b</VAR>.</P>
+<P>An eavesdropper will know<VAR> p</VAR> and<VAR> g</VAR> since these
+ are made public, and can intercept<VAR> A</VAR> and<VAR> B</VAR> but,
+ short of solving the<A href="#dlog"> discrete log</A> problem, these do
+ not let him or her discover the secret<VAR> s</VAR>.</P>
+</DD>
+<DT><A name="signature">Digital signature</A></DT>
+<DD>Sender:
+<UL>
+<LI>calculates a<A href="#digest"> message digest</A> of a document</LI>
+<LI>encrypts the digest with his or her private key, using some<A href="#public">
+ public key cryptosystem</A>.</LI>
+<LI>attaches the encrypted digest to the document as a signature</LI>
+</UL>
+<P>Receiver:</P>
+<UL>
+<LI>calculates a digest of the document (not including the signature)</LI>
+<LI>decrypts the signature with the signer's public key</LI>
+<LI>verifies that the two results are identical</LI>
+</UL>
+<P>If the public-key system is secure and the verification succeeds,
+ then the receiver knows</P>
+<UL>
+<LI>that the document was not altered between signing and verification</LI>
+<LI>that the signer had access to the private key</LI>
+</UL>
+<P>Such an encrypted message digest can be treated as a signature since
+ it cannot be created without<EM> both</EM> the document<EM> and</EM>
+ the private key which only the sender should possess. The<A href="web.html#legal">
+ legal issues</A> are complex, but several countries are moving in the
+ direction of legal recognition for digital signatures.</P>
+</DD>
+<DT><A name="dlog">discrete logarithm problem</A></DT>
+<DD>The problem of finding logarithms in a finite field. Given a field
+ defintion (such definitions always include some operation analogous to
+ multiplication) and two numbers, a base and a target, find the power
+ which the base must be raised to in order to yield the target.
+<P>The discrete log problem is the basis of several cryptographic
+ systems, including the<A href="#DH"> Diffie-Hellman</A> key exchange
+ used in the<A href="#IKE"> IKE</A> protocol. The useful property is
+ that exponentiation is relatively easy but the inverse operation,
+ finding the logarithm, is hard. The cryptosystems are designed so that
+ the user does only easy operations (exponentiation in the field) but an
+ attacker must solve the hard problem (discrete log) to crack the
+ system.</P>
+<P>There are several variants of the problem for different types of
+ field. The IKE/Oakley key determination protocol uses two variants,
+ either over a field modulo a prime or over a field defined by an
+ elliptic curve. We give an example modulo a prime below. For the
+ elliptic curve version, consult an advanced text such as<A href="biblio.html#handbook">
+ Handbook of Applied Cryptography</A>.</P>
+<P>Given a prime<VAR> p</VAR>, a generator<VAR> g</VAR> for the field
+ modulo that prime, and a number<VAR> x</VAR> in the field, the problem
+ is to find<VAR> y</VAR> such that<VAR> g^y = x</VAR>.</P>
+<P>For example, let p = 13. The field is then the integers from 0 to 12.
+ Any integer equals one of these modulo 13. That is, the remainder when
+ any integer is divided by 13 must be one of these.</P>
+<P>2 is a generator for this field. That is, the powers of two modulo 13
+ run through all the non-zero numbers in the field. Modulo 13 we have:</P>
+<PRE>          y      x
+        2^0  ==  1
+        2^1  ==  2
+        2^2  ==  4
+        2^3  ==  8
+        2^4  ==  3 that is, the remainder from 16/13 is 3
+        2^5  ==  6          the remainder from 32/13 is 6
+        2^6  == 12 and so on
+        2^7  == 11
+        2^8  ==  9
+        2^9  ==  5
+        2^10 == 10
+        2^11 ==  7
+        2^12 ==  1</PRE>
+<P>Exponentiation in such a field is not difficult. Given, say,<NOBR><VAR>
+ y = 11</VAR>,calculating<NOBR><VAR> x = 7</VAR>is straightforward. One
+ method is just to calculate<NOBR><VAR> 2^11 = 2048</VAR>,then<NOBR><VAR>
+ 2048 mod 13 == 7</VAR>.When the field is modulo a large prime (say a
+ few 100 digits) you need a silghtly cleverer method and even that is
+ moderately expensive in computer time, but the calculation is still not
+ problematic in any basic way.</P>
+<P>The discrete log problem is the reverse. In our example, given<NOBR><VAR>
+ x = 7</VAR>,find the logarithm<NOBR><VAR> y = 11</VAR>.When the field
+ is modulo a large prime (or is based on a suitable elliptic curve),
+ this is indeed problematic. No solution method that is not
+ catastrophically expensive is known. Quite a few mathematicians have
+ tackled this problem. No efficient method has been found and
+ mathematicians do not expect that one will be. It seems likely no
+ efficient solution to either of the main variants the discrete log
+ problem exists.</P>
+<P>Note, however, that no-one has proven such methods do not exist. If a
+ solution to either variant were found, the security of any crypto
+ system using that variant would be destroyed. This is one reason<A href="#IKE">
+ IKE</A> supports two variants. If one is broken, we can switch to the
+ other.</P>
+</DD>
+<DT><A name="discretionary">discretionary access control</A></DT>
+<DD>access control mechanisms controlled by the user, for example Unix
+ rwx file permissions. These contrast with<A href="#mandatory">
+ mandatory access controls</A>.</DD>
+<DT><A name="DNS">DNS</A></DT>
+<DD><B>D</B>omain<B> N</B>ame<B> S</B>ervice, a distributed database
+ through which names are associated with numeric addresses and other
+ information in the Internet Protocol Suite. See also the<A href="background.html#dns.background">
+ DNS background</A> section of our documentation.</DD>
+<DT>DOS attack</DT>
+<DD>see<A href="#DOS"> Denial Of Service</A> attack</DD>
+<DT><A name="dynamic">dynamic IP address</A></DT>
+<DD>an IP address which is automatically assigned, either by<A href="#DHCP">
+ DHCP</A> or by some protocol such as<A href="#PPP"> PPP</A> or<A href="#PPPoE">
+ PPPoE</A> which the machine uses to connect to the Internet. This is
+ the opposite of a<A href="#static"> static IP address</A>, pre-set on
+ the machine itself.</DD>
+<DT><A name="E">E</A></DT>
+<DT><A name="EAR">EAR</A></DT>
+<DD>The US government's<B> E</B>xport<B> A</B>dministration<B> R</B>
+egulations, administered by the<A href="#BXA"> Bureau of Export
+ Administration</A>. These have replaced the earlier<A href="#ITAR">
+ ITAR</A> regulations as the controls on export of cryptography.</DD>
+<DT><A name="ECB">ECB mode</A></DT>
+<DD><B>E</B>lectronic<B> C</B>ode<B>B</B>ook mode, the simplest way to
+ use a block cipher. See<A href="#mode"> Cipher Modes</A>.</DD>
+<DT><A name="EDE">EDE</A></DT>
+<DD>The sequence of operations normally used in either the three-key
+ variant of<A href="#3DES"> triple DES</A> used in<A href="#IPSEC">
+ IPsec</A> or the<A href="#2key"> two-key</A> variant used in some other
+ systems.
+<P>The sequence is:</P>
+<UL>
+<LI><B>E</B>ncrypt with key1</LI>
+<LI><B>D</B>ecrypt with key2</LI>
+<LI><B>E</B>ncrypt with key3</LI>
+</UL>
+<P>For the two-key version, key1=key3.</P>
+<P>The &quot;advantage&quot; of this EDE order of operations is that it makes it
+ simple to interoperate with older devices offering only single DES. Set
+ key1=key2=key3 and you have the worst of both worlds, the overhead of
+ triple DES with the &quot;security&quot; of single DES. Since both the<A href="politics.html#desnotsecure">
+ security of single DES</A> and the overheads of triple DES are
+ seriously inferior to many other ciphers, this is a spectacularly
+ dubious &quot;advantage&quot;.</P>
+</DD>
+<DT><A name="Entrust">Entrust</A></DT>
+<DD>A Canadian company offerring enterprise<A href="#PKI"> PKI</A>
+ products using<A href="#CAST128"> CAST-128</A> symmetric crypto,<A href="#RSA">
+ RSA</A> public key and<A href="#X509"> X.509</A> directories.<A href="http://www.entrust.com">
+ Web site</A></DD>
+<DT><A name="EFF">EFF</A></DT>
+<DD><A href="http://www.eff.org">Electronic Frontier Foundation</A>, an
+ advocacy group for civil rights in cyberspace.</DD>
+<DT><A name="encryption">Encryption</A></DT>
+<DD>Techniques for converting a readable message (<A href="#plaintext">
+plaintext</A>) into apparently random material (<A href="#ciphertext">
+ciphertext</A>) which cannot be read if intercepted. A key is required
+ to read the message.
+<P>Major variants include<A href="#symmetric"> symmetric</A> encryption
+ in which sender and receiver use the same secret key and<A href="#public">
+ public key</A> methods in which the sender uses one of a matched pair
+ of keys and the receiver uses the other. Many current systems,
+ including<A href="#IPSEC"> IPsec</A>, are<A href="#hybrid"> hybrids</A>
+ combining the two techniques.</P>
+</DD>
+<DT><A name="ESP">ESP</A></DT>
+<DD><B>E</B>ncapsulated<B> S</B>ecurity<B> P</B>ayload, the<A href="#IPSEC">
+ IPsec</A> protocol which provides<A href="#encryption"> encryption</A>.
+ It can also provide<A href="#authentication"> authentication</A>
+ service and may be used with null encryption (which we do not
+ recommend). For details see our<A href="ipsec.html#ESP.ipsec"> IPsec</A>
+ document and/or RFC 2406.</DD>
+<DT><A name="#extruded">Extruded subnet</A></DT>
+<DD>A situation in which something IP sees as one network is actually in
+ two or more places.
+<P>For example, the Internet may route all traffic for a particular
+ company to that firm's corporate gateway. It then becomes the company's
+ problem to get packets to various machines on their<A href="#subnet">
+ subnets</A> in various departments. They may decide to treat a branch
+ office like a subnet, giving it IP addresses &quot;on&quot; their corporate net.
+ This becomes an extruded subnet.</P>
+<P>Packets bound for it are delivered to the corporate gateway, since as
+ far as the outside world is concerned, that subnet is part of the
+ corporate network. However, instead of going onto the corporate LAN (as
+ they would for, say, the accounting department) they are then
+ encapsulated and sent back onto the Internet for delivery to the branch
+ office.</P>
+<P>For information on doing this with Linux FreeS/WAN, look in our<A href="adv_config.html#extruded.config">
+ advanced configuration</A> section.</P>
+</DD>
+<DT>Exhaustive search</DT>
+<DD>See<A href="#brute"> brute force attack</A>.</DD>
+<DT><A name="F">F</A></DT>
+<DT><A name="FIPS">FIPS</A></DT>
+<DD><B>F</B>ederal<B> I</B>nformation<B> P</B>rocessing<B> S</B>tandard,
+ the US government's standards for products it buys. These are issued by<A
+href="#NIST"> NIST</A>. Among other things,<A href="#DES"> DES</A> and<A href="#SHA">
+ SHA</A> are defined in FIPS documents. NIST have a<A href="http://www.itl.nist.gov/div897/pubs">
+ FIPS home page</A>.</DD>
+<DT><A name="FSF">Free Software Foundation (FSF)</A></DT>
+<DD>An organisation to promote free software, free in the sense of these
+ quotes from their web pages</DD>
+<DD><BLOCKQUOTE> &quot;Free software&quot; is a matter of liberty, not price. To
+ understand the concept, you should think of &quot;free speech&quot;, not &quot;free
+ beer.&quot;
+<P>&quot;Free software&quot; refers to the users' freedom to run, copy,
+ distribute, study, change and improve the software.</P>
+</BLOCKQUOTE>
+<P>See also<A href="#GNU"> GNU</A>,<A href="#GPL"> GNU General Public
+ License</A>, and<A href="http://www.fsf.org"> the FSF site</A>.</P>
+</DD>
+<DT>FreeS/WAN</DT>
+<DD>see<A href="web.html#FreeSWAN"> Linux FreeS/WAN</A></DD>
+<DT><A name="fullnet">Fullnet</A></DT>
+<DD>The CIDR block containing all IPs of its IP version. The<A HREF="#IPv4">
+ IPv4</A> fullnet is written 0.0.0.0/0. Also known as &quot;all&quot; and
+ &quot;default&quot;, fullnet may be used in a routing table to specify a default
+ route, and in a FreeS/WAN<A HREF="policygroups.html#policygroups">
+ policy group</A> file to specify a default IPsec policy.</DD>
+<DT>FSF</DT>
+<DD>see<A href="#FSF"> Free software Foundation</A></DD>
+<DT><A name="G">G</A></DT>
+<DT><A name="GCHQ">GCHQ</A></DT>
+<DD><A href="http://www.gchq.gov.uk">Government Communications
+ Headquarters</A>, the British organisation for<A href="#SIGINT">
+ signals intelligence</A>.</DD>
+<DT>generator of a prime field</DT>
+<DD>see<A href="#dlog"> discrete logarithm problem</A></DD>
+<DT><A name="GILC">GILC</A></DT>
+<DD><A href="http://www.gilc.org">Global Internet Liberty Campaign</A>,
+ an international organisation advocating, among other things, free
+ availability of cryptography. They have a<A href="http://www.gilc.org/crypto/wassenaar">
+ campaign</A> to remove cryptographic software from the<A href="#Wassenaar.gloss">
+ Wassenaar Arrangement</A>.</DD>
+<DT>Global Internet Liberty Campaign</DT>
+<DD>see<A href="#GILC"> GILC</A>.</DD>
+<DT><A name="GTR">Global Trust Register</A></DT>
+<DD>An attempt to create something like a<A href="#rootCA"> root CA</A>
+ for<A href="#PGP"> PGP</A> by publishing both<A href="biblio.html#GTR">
+ as a book</A> and<A href="http://www.cl.cam.ac.uk/Research/Security/Trust-Register">
+ on the web</A> the fingerprints of a set of verified keys for
+ well-known users and organisations.</DD>
+<DT><A name="GMP">GMP</A></DT>
+<DD>The<B> G</B>NU<B> M</B>ulti-<B>P</B>recision library code, used in<A href="web.html#FreeSWAN">
+ Linux FreeS/WAN</A> by<A href="#Pluto"> Pluto</A> for<A href="#public">
+ public key</A> calculations. See the<A href="http://www.swox.com/gmp">
+ GMP home page</A>.</DD>
+<DT><A name="GNU">GNU</A></DT>
+<DD><B>G</B>NU's<B> N</B>ot<B> U</B>nix, the<A href="#FSF"> Free
+ Software Foundation's</A> project aimed at creating a free system with
+ at least the capabilities of Unix.<A href="#Linux"> Linux</A> uses GNU
+ utilities extensively.</DD>
+<DT><A name="#GOST">GOST</A></DT>
+<DD>a Soviet government standard<A href="#block"> block cipher</A>.<A href="biblio.html#schneier">
+ Applied Cryptography</A> has details.</DD>
+<DT>GPG</DT>
+<DD>see<A href="#GPG"> GNU Privacy Guard</A></DD>
+<DT><A name="GPL">GNU General Public License</A>(GPL, copyleft)</DT>
+<DD>The license developed by the<A href="#FSF"> Free Software Foundation</A>
+ under which<A href="#Linux"> Linux</A>,<A href="web.html#FreeSWAN">
+ Linux FreeS/WAN</A> and many other pieces of software are distributed.
+ The license allows anyone to redistribute and modify the code, but
+ forbids anyone from distributing executables without providing access
+ to source code. For more details see the file<A href="../COPYING">
+ COPYING</A> included with GPLed source distributions, including ours,
+ or<A href="http://www.fsf.org/copyleft/gpl.html"> the GNU site's GPL
+ page</A>.</DD>
+<DT><A name="GPG">GNU Privacy Guard</A></DT>
+<DD>An open source implementation of Open<A href="#PGP"> PGP</A> as
+ defined in RFC 2440. See their<A href="http://www.gnupg.org"> web site</A>
+</DD>
+<DT>GPL</DT>
+<DD>see<A href="#GPL"> GNU General Public License</A>.</DD>
+<DT><A name="H">H</A></DT>
+<DT><A name="hash">Hash</A></DT>
+<DD>see<A href="#digest"> message digest</A></DD>
+<DT><A name="HMAC">Hashed Message Authentication Code (HMAC)</A></DT>
+<DD>using keyed<A href="#digest"> message digest</A> functions to
+ authenticate a message. This differs from other uses of these
+ functions:
+<UL>
+<LI>In normal usage, the hash function's internal variable are
+ initialised in some standard way. Anyone can reproduce the hash to
+ check that the message has not been altered.</LI>
+<LI>For HMAC usage, you initialise the internal variables from the key.
+ Only someone with the key can reproduce the hash. A successful check of
+ the hash indicates not only that the message is unchanged but also that
+ the creator knew the key.</LI>
+</UL>
+<P>The exact techniques used in<A href="#IPSEC"> IPsec</A> are defined
+ in RFC 2104. They are referred to as HMAC-MD5-96 and HMAC-SHA-96
+ because they output only 96 bits of the hash. This makes some attacks
+ on the hash functions harder.</P>
+</DD>
+<DT>HMAC</DT>
+<DD>see<A href="#HMAC"> Hashed Message Authentication Code</A></DD>
+<DT>HMAC-MD5-96</DT>
+<DD>see<A href="#HMAC"> Hashed Message Authentication Code</A></DD>
+<DT>HMAC-SHA-96</DT>
+<DD>see<A href="#HMAC"> Hashed Message Authentication Code</A></DD>
+<DT><A name="hybrid">Hybrid cryptosystem</A></DT>
+<DD>A system using both<A href="#public"> public key</A> and<A href="#symmetric">
+ symmetric cipher</A> techniques. This works well. Public key methods
+ provide key management and<A href="#signature"> digital signature</A>
+ facilities which are not readily available using symmetric ciphers. The
+ symmetric cipher, however, can do the bulk of the encryption work much
+ more efficiently than public key methods.</DD>
+<DT><A name="I">I</A></DT>
+<DT><A name="IAB">IAB</A></DT>
+<DD><A href="http://www.iab.org/iab">Internet Architecture Board</A>.</DD>
+<DT><A name="ICMP.gloss">ICMP</A></DT>
+<DD><STRONG>I</STRONG>nternet<STRONG> C</STRONG>ontrol<STRONG> M</STRONG>
+essage<STRONG> P</STRONG>rotocol. This is used for various IP-connected
+ devices to manage the network.</DD>
+<DT><A name="IDEA">IDEA</A></DT>
+<DD><B>I</B>nternational<B> D</B>ata<B> E</B>ncrypion<B> A</B>lgorithm,
+ developed in Europe as an alternative to exportable American ciphers
+ such as<A href="#DES"> DES</A> which were<A href="politics.html#desnotsecure">
+ too weak for serious use</A>. IDEA is a<A href="#block"> block cipher</A>
+ using 64-bit blocks and 128-bit keys, and is used in products such as<A href="#PGP">
+ PGP</A>.
+<P>IDEA is not required by the<A href="#IPSEC"> IPsec</A> RFCs and not
+ currently used in<A href="web.html#FreeSWAN"> Linux FreeS/WAN</A>.</P>
+<P>IDEA is patented and, with strictly limited exceptions for personal
+ use, using it requires a license from<A href="http://www.ascom.com">
+ Ascom</A>.</P>
+</DD>
+<DT><A name="IEEE">IEEE</A></DT>
+<DD><A href="http://www.ieee.org">Institute of Electrical and Electronic
+ Engineers</A>, a professional association which, among other things,
+ sets some technical standards</DD>
+<DT><A name="IESG">IESG</A></DT>
+<DD><A href="http://www.iesg.org">Internet Engineering Steering Group</A>
+.</DD>
+<DT><A name="IETF">IETF</A></DT>
+<DD><A href="http://www.ietf.org">Internet Engineering Task Force</A>,
+ the umbrella organisation whose various working groups make most of the
+ technical decisions for the Internet. The IETF<A href="http://www.ietf.org/html.charters/ipsec-charter.html">
+ IPsec working group</A> wrote the<A href="rfc.html#RFC"> RFCs</A> we
+ are implementing.</DD>
+<DT><A name="IKE">IKE</A></DT>
+<DD><B>I</B>nternet<B> K</B>ey<B> E</B>xchange, based on the<A href="#DH">
+ Diffie-Hellman</A> key exchange protocol. For details, see RFC 2409 and
+ our<A href="ipsec.html"> IPsec</A> document. IKE is implemented in<A href="web.html#FreeSWAN">
+ Linux FreeS/WAN</A> by the<A href="#Pluto"> Pluto daemon</A>.</DD>
+<DT>IKE v2</DT>
+<DD>A proposed replacement for<A href="#IKE"> IKE</A>. There are other
+ candidates, such as<A href="#JFK"> JFK</A>, and at time of writing
+ (March 2002) the choice between them has not yet been made and does not
+ appear imminent.</DD>
+<DT><A name="iOE">iOE</A></DT>
+<DD>See<A HREF="#initiate-only"> Initiate-only opportunistic encryption</A>
+.</DD>
+<DT><A name="IP">IP</A></DT>
+<DD><B>I</B>nternet<B> P</B>rotocol.</DD>
+<DT><A name="masq">IP masquerade</A></DT>
+<DD>A mostly obsolete term for a method of allowing multiple machines to
+ communicate over the Internet when only one IP address is available for
+ their use. The more current term is Network Address Translation or<A href="#NAT.gloss">
+ NAT</A>.</DD>
+<DT><A name="IPng">IPng</A></DT>
+<DD>&quot;IP the Next Generation&quot;, see<A href="#ipv6.gloss"> IPv6</A>.</DD>
+<DT><A name="IPv4">IPv4</A></DT>
+<DD>The current version of the<A href="#IP"> Internet protocol suite</A>
+.</DD>
+<DT><A name="ipv6.gloss">IPv6 (IPng)</A></DT>
+<DD>Version six of the<A href="#IP"> Internet protocol suite</A>,
+ currently being developed. It will replace the current<A href="#IPv4">
+ version four</A>. IPv6 has<A href="#IPSEC"> IPsec</A> as a mandatory
+ component.
+<P>See this<A href="http://playground.sun.com/pub/ipng/html/ipng-main.html">
+ web site</A> for more details, and our<A href="compat.html#ipv6">
+ compatibility</A> document for information on FreeS/WAN and the Linux
+ implementation of IPv6.</P>
+</DD>
+<DT><A name="IPSEC">IPsec</A> or IPSEC</DT>
+<DD><B>I</B>nternet<B> P</B>rotocol<B> SEC</B>urity, security functions
+ (<A href="#authentication">authentication</A> and<A href="#encryption">
+ encryption</A>) implemented at the IP level of the protocol stack. It
+ is optional for<A href="#IPv4"> IPv4</A> and mandatory for<A href="#ipv6.gloss">
+ IPv6</A>.
+<P>This is the standard<A href="web.html#FreeSWAN"> Linux FreeS/WAN</A>
+ is implementing. For more details, see our<A href="ipsec.html"> IPsec
+ Overview</A>. For the standards, see RFCs listed in our<A href="rfc.html#RFC">
+ RFCs document</A>.</P>
+</DD>
+<DT><A name="IPX">IPX</A></DT>
+<DD>Novell's Netware protocol tunnelled over an IP link. Our<A href="firewall.html#user.scripts">
+ firewalls</A> document includes an example of using this through an
+ IPsec tunnel.</DD>
+<DT><A name="ISAKMP">ISAKMP</A></DT>
+<DD><B>I</B>nternet<B> S</B>ecurity<B> A</B>ssociation and<B> K</B>ey<B>
+ M</B>anagement<B> P</B>rotocol, defined in RFC 2408.</DD>
+<DT><A name="ITAR">ITAR</A></DT>
+<DD><B>I</B>nternational<B> T</B>raffic in<B> A</B>rms<B> R</B>
+egulations, US regulations administered by the State Department which
+ until recently limited export of, among other things, cryptographic
+ technology and software. ITAR still exists, but the limits on
+ cryptography have now been transferred to the<A href="#EAR"> Export
+ Administration Regulations</A> under the Commerce Department's<A href="#BXA">
+ Bureau of Export Administration</A>.</DD>
+<DT>IV</DT>
+<DD>see<A href="#IV"> Initialisation vector</A></DD>
+<DT><A name="IV">Initialisation Vector (IV)</A></DT>
+<DD>Some cipher<A href="#mode"> modes</A>, including the<A href="#CBC">
+ CBC</A> mode which IPsec uses, require some extra data at the
+ beginning. This data is called the initialisation vector. It need not
+ be secret, but should be different for each message. Its function is to
+ prevent messages which begin with the same text from encrypting to the
+ same ciphertext. That might give an analyst an opening, so it is best
+ prevented.</DD>
+<DT><A name="initiate-only">Initiate-only opportunistic encryption (iOE)</A>
+</DT>
+<DD>A form of<A HREF="#carpediem"> opportunistic encryption</A> (OE) in
+ which a host proposes opportunistic connections, but lacks the reverse
+ DNS records necessary to support incoming opportunistic connection
+ requests. Common among hosts on cable or pppoe connections where the
+ system administrator does not have write access to the DNS reverse map
+ for the host's external IP.
+<P>Configuring for initiate-only opportunistic encryption is described
+ in our<A href="quickstart.html#opp.client"> quickstart</A> document.</P>
+</DD>
+<DT><A name="J">J</A></DT>
+<DT><A name="JFK">JFK</A></DT>
+<DD><STRONG>J</STRONG>ust<STRONG> F</STRONG>ast<STRONG> K</STRONG>eying,
+ a proposed simpler replacement for<A href="#IKE"> IKE.</A></DD>
+<DT><A name="K">K</A></DT>
+<DT><A name="kernel">Kernel</A></DT>
+<DD>The basic part of an operating system (e.g. Linux) which controls
+ the hardware and provides services to all other programs.
+<P>In the Linux release numbering system, an even second digit as in 2.<STRONG>
+2</STRONG>.x indicates a stable or production kernel while an odd number
+ as in 2.<STRONG>3</STRONG>.x indicates an experimental or development
+ kernel. Most users should run a recent kernel version from the
+ production series. The development kernels are primarily for people
+ doing kernel development. Others should consider using development
+ kernels only if they have an urgent need for some feature not yet
+ available in production kernels.</P>
+</DD>
+<DT>Keyed message digest</DT>
+<DD>See<A href="#HMAC"> HMAC</A>.</DD>
+<DT>Key length</DT>
+<DD>see<A href="#brute"> brute force attack</A></DD>
+<DT><A name="KLIPS">KLIPS</A></DT>
+<DD><B>K</B>erne<B>l</B><B> IP</B><B> S</B>ecurity, the<A href="web.html#FreeSWAN">
+ Linux FreeS/WAN</A> project's changes to the<A href="#Linux"> Linux</A>
+ kernel to support the<A href="#IPSEC"> IPsec</A> protocols.</DD>
+<DT><A name="L">L</A></DT>
+<DT><A name="LDAP">LDAP</A></DT>
+<DD><B>L</B>ightweight<B> D</B>irectory<B> A</B>ccess<B> P</B>rotocol,
+ defined in RFCs 1777 and 1778, a method of accessing information stored
+ in directories. LDAP is used by several<A href="#PKI"> PKI</A>
+ implementations, often with X.501 directories and<A href="#X509"> X.509</A>
+ certificates. It may also be used by<A href="#IPSEC"> IPsec</A> to
+ obtain key certifications from those PKIs. This is not yet implemented
+ in<A href="web.html#FreeSWAN"> Linux FreeS/WAN</A>.</DD>
+<DT><A name="LIBDES">LIBDES</A></DT>
+<DD>A publicly available library of<A href="#DES"> DES</A> code, written
+ by Eric Young, which<A href="web.html#FreeSWAN"> Linux FreeS/WAN</A>
+ uses in both<A href="#KLIPS"> KLIPS</A> and<A href="#Pluto"> Pluto</A>.</DD>
+<DT><A name="Linux">Linux</A></DT>
+<DD>A freely available Unix-like operating system based on a kernel
+ originally written for the Intel 386 architecture by (then) student
+ Linus Torvalds. Once his 32-bit kernel was available, the<A href="#GNU">
+ GNU</A> utilities made it a usable system and contributions from many
+ others led to explosive growth.
+<P>Today Linux is a complete Unix replacement available for several CPU
+ architectures -- Intel, DEC/Compaq Alpha, Power PC, both 32-bit SPARC
+ and the 64-bit UltraSPARC, SrongARM, . . . -- with support for multiple
+ CPUs on some architectures.</P>
+<P><A href="web.html#FreeSWAN">Linux FreeS/WAN</A> is intended to run on
+ all CPUs supported by Linux and is known to work on several. See our<A href="compat.html#CPUs">
+ compatibility</A> section for a list.</P>
+</DD>
+<DT><A name="FreeSWAN">Linux FreeS/WAN</A></DT>
+<DD>Our implementation of the<A href="#IPSEC"> IPsec</A> protocols,
+ intended to be freely redistributable source code with<A href="#GPL"> a
+ GNU GPL license</A> and no constraints under US or other<A href="politics.html#exlaw">
+ export laws</A>. Linux FreeS/WAN is intended to interoperate with other<A
+href="#IPSEC"> IPsec</A> implementations. The name is partly taken, with
+ permission, from the<A href="#SWAN"> S/WAN</A> multi-vendor IPsec
+ compatability effort. Linux FreeS/WAN has two major components,<A href="#KLIPS">
+ KLIPS</A> (KerneL IPsec Support) and the<A href="#Pluto"> Pluto</A>
+ daemon which manages the whole thing.
+<P>See our<A href="ipsec.html"> IPsec section</A> for more detail. For
+ the code see our<A href="http://freeswan.org"> primary site</A> or one
+ of the mirror sites on<A href="intro.html#mirrors"> this list</A>.</P>
+</DD>
+<DT><A name="LSM">Linux Security Modules (LSM)</A></DT>
+<DD>a project to create an interface in the Linux kernel that supports
+ plug-in modules for various security policies.
+<P>This allows multiple security projects to take different approaches
+ to security enhancement without tying the kernel down to one particular
+ approach. As I understand the history, several projects were pressing
+ Linus to incorporate their changes, the various sets of changes were
+ incompatible, and his answer was more-or-less &quot;a plague on all your
+ houses; I'll give you an interface, but I won't incorporate anything&quot;.</P>
+<P>It seems to be working. There is a fairly active<A href="http://mail.wirex.com/mailman/listinfo/linux-security-module">
+ LSM mailing list</A>, and several projects are already using the
+ interface.</P>
+</DD>
+<DT>LSM</DT>
+<DD>see<A href="#LSM"> Linux Security Modules</A></DD>
+<DT><A name="M">M</A></DT>
+<DT><A name="list">Mailing list</A></DT>
+<DD>The<A href="web.html#FreeSWAN"> Linux FreeS/WAN</A> project has
+ several public email lists for bug reports and software development
+ discussions. See our document on<A href="mail.html"> mailing lists</A>.</DD>
+<DT><A name="middle">Man-in-the-middle attack</A></DT>
+<DD>An<A href="#active"> active attack</A> in which the attacker
+ impersonates each of the legitimate players in a protocol to the other.
+<P>For example, if<A href="#alicebob"> Alice and Bob</A> are negotiating
+ a key via the<A href="#DH"> Diffie-Hellman</A> key agreement, and are
+ not using<A href="#authentication"> authentication</A> to be certain
+ they are talking to each other, then an attacker able to insert himself
+ in the communication path can deceive both players.</P>
+<P>Call the attacker Mallory. For Bob, he pretends to be Alice. For
+ Alice, he pretends to be Bob. Two keys are then negotiated,
+ Alice-to-Mallory and Bob-to-Mallory. Alice and Bob each think the key
+ they have is Alice-to-Bob.</P>
+<P>A message from Alice to Bob then goes to Mallory who decrypts it,
+ reads it and/or saves a copy, re-encrypts using the Bob-to-Mallory key
+ and sends it along to Bob. Bob decrypts successfully and sends a reply
+ which Mallory decrypts, reads, re-encrypts and forwards to Alice.</P>
+<P>To make this attack effective, Mallory must</P>
+<UL>
+<LI>subvert some part of the network in some way that lets him carry out
+ the deception
+<BR> possible targets: DNS, router, Alice or Bob's machine, mail server,
+ ...</LI>
+<LI>beat any authentication mechanism Alice and Bob use
+<BR> strong authentication defeats the attack entirely; this is why<A href="#IKE">
+ IKE</A> requires authentication</LI>
+<LI>work in real time, delivering messages without introducing a delay
+ large enough to alert the victims
+<BR> not hard if Alice and Bob are using email; quite difficult in some
+ situations.</LI>
+</UL>
+<P>If he manages it, however, it is devastating. He not only gets to
+ read all the messages; he can alter messages, inject his own, forge
+ anything he likes, . . . In fact, he controls the communication
+ completely.</P>
+</DD>
+<DT><A name="mandatory">mandatory access control</A></DT>
+<DD>access control mechanisims which are not settable by the user (see<A href="#discretionary">
+ discretionary access control</A>), but are enforced by the system.
+<P>For example, a document labelled &quot;secret, zebra&quot; might be readable
+ only by someone with secret clearance working on Project Zebra.
+ Ideally, the system will prevent any transfer outside those boundaries.
+ For example, even if you can read it, you should not be able to e-mail
+ it (unless the recipient is appropriately cleared) or print it (unless
+ certain printers are authorised for that classification).</P>
+<P>Mandatory access control is a required feature for some levels of<A href="#rainbow">
+ Rainbow Book</A> or<A href="#cc"> Common Criteria</A> classification,
+ but has not been widely used outside the military and government. There
+ is a good discussion of the issues in Anderson's<A href="biblio.html#anderson">
+ Security Engineering</A>.</P>
+<P>The<A href="#SElinux"> Security Enhanced Linux</A> project is adding
+ mandatory access control to Linux.</P>
+</DD>
+<DT><A name="manual">Manual keying</A></DT>
+<DD>An IPsec mode in which the keys are provided by the administrator.
+ In FreeS/WAN, they are stored in /etc/ipsec.conf. The alternative,<A href="ipsec.html#auto">
+ automatic keying</A>, is preferred in most cases. See this<A href="adv_config.html#man-auto">
+ discussion</A>.</DD>
+<DT><A name="MD4">MD4</A></DT>
+<DD><A href="#digest">Message Digest Algorithm</A> Four from Ron Rivest
+ of<A href="#RSAco"> RSA</A>. MD4 was widely used a few years ago, but
+ is now considered obsolete. It has been replaced by its descendants<A href="#MD5">
+ MD5</A> and<A href="#SHA"> SHA</A>.</DD>
+<DT><A name="MD5">MD5</A></DT>
+<DD><A href="#digest">Message Digest Algorithm</A> Five from Ron Rivest
+ of<A href="#RSAco"> RSA</A>, an improved variant of his<A href="#MD4">
+ MD4</A>. Like MD4, it produces a 128-bit hash. For details see RFC
+ 1321.
+<P>MD5 is one of two message digest algorithms available in IPsec. The
+ other is<A href="#SHA"> SHA</A>. SHA produces a longer hash and is
+ therefore more resistant to<A href="#birthday"> birthday attacks</A>,
+ but this is not a concern for IPsec. The<A href="#HMAC"> HMAC</A>
+ method used in IPsec is secure even if the underlying hash is not
+ particularly strong against this attack.</P>
+<P>Hans Dobbertin found a weakness in MD5, and people often ask whether
+ this means MD5 is unsafe for IPsec. It doesn't. The IPsec RFCs discuss
+ Dobbertin's attack and conclude that it does not affect MD5 as used for
+ HMAC in IPsec.</P>
+</DD>
+<DT><A name="meet">Meet-in-the-middle attack</A></DT>
+<DD>A divide-and-conquer attack which breaks a cipher into two parts,
+ works against each separately, and compares results. Probably the best
+ known example is an attack on double DES. This applies in principle to
+ any pair of block ciphers, e.g. to an encryption system using, say,
+ CAST-128 and Blowfish, but we will describe it for double DES.
+<P>Double DES encryption and decryption can be written:</P>
+<PRE>        C = E(k2,E(k1,P))
+        P = D(k1,D(k2,C))</PRE>
+<P>Where C is ciphertext, P is plaintext, E is encryption, D is
+ decryption, k1 is one key, and k2 is the other key. If we know a P, C
+ pair, we can try and find the keys with a brute force attack, trying
+ all possible k1, k2 pairs. Since each key is 56 bits, there are 2<SUP>
+112</SUP> such pairs and this attack is painfully inefficient.</P>
+<P>The meet-in-the middle attack re-writes the equations to calculate a
+ middle value M:</P>
+<PRE>        M = E(k1,P)
+        M = D(k2,C)</PRE>
+<P>Now we can try some large number of D(k2,C) decryptions with various
+ values of k2 and store the results in a table. Then start doing E(k1,P)
+ encryptions, checking each result to see if it is in the table.</P>
+<P>With enough table space, this breaks double DES with<NOBR> 2<SUP>56</SUP>
+ + 2<SUP>56</SUP> = 2<SUP>57</SUP>work. Against triple DES, you need<NOBR>
+ 2<SUP>56</SUP> + 2<SUP>112</SUP> ~= 2<SUP>112</SUP>.</P>
+<P>The memory requirements for such attacks can be prohibitive, but
+ there is a whole body of research literature on methods of reducing
+ them.</P>
+</DD>
+<DT><A name="digest">Message Digest Algorithm</A></DT>
+<DD>An algorithm which takes a message as input and produces a hash or
+ digest of it, a fixed-length set of bits which depend on the message
+ contents in some highly complex manner. Design criteria include making
+ it extremely difficult for anyone to counterfeit a digest or to change
+ a message without altering its digest. One essential property is<A href="#collision">
+ collision resistance</A>. The main applications are in message<A href="#authentication">
+ authentication</A> and<A href="#signature"> digital signature</A>
+ schemes. Widely used algorithms include<A href="#MD5"> MD5</A> and<A href="#SHA">
+ SHA</A>. In IPsec, message digests are used for<A href="#HMAC"> HMAC</A>
+ authentication of packets.</DD>
+<DT><A name="MTU">MTU</A></DT>
+<DD><STRONG>M</STRONG>aximum<STRONG> T</STRONG>ransmission<STRONG> U</STRONG>
+nit, the largest size of packet that can be sent over a link. This is
+ determined by the underlying network, but must be taken account of at
+ the IP level.
+<P>IP packets, which can be up to 64K bytes each, must be packaged into
+ lower-level packets of the appropriate size for the underlying
+ network(s) and re-assembled on the other end. When a packet must pass
+ over multiple networks, each with its own MTU, and many of the MTUs are
+ unknown to the sender, this becomes a fairly complex problem. See<A href="#pathMTU">
+ path MTU discovery</A> for details.</P>
+<P>Often the MTU is a few hundred bytes on serial links and 1500 on
+ Ethernet. There are, however, serial link protocols which use a larger
+ MTU to avoid fragmentation at the ethernet/serial boundary, and newer
+ (especially gigabit) Ethernet networks sometimes support much larger
+ packets because these are more efficient in some applications.</P>
+</DD>
+<DT><A name="N">N</A></DT>
+<DT><A name="NAI">NAI</A></DT>
+<DD><A href="http://www.nai.com">Network Associates</A>, a conglomerate
+ formed from<A href="#PGPI"> PGP Inc.</A>, TIS (Trusted Information
+ Systems, a firewall vendor) and McAfee anti-virus products. Among other
+ things, they offer an IPsec-based VPN product.</DD>
+<DT><A name="NAT.gloss">NAT</A></DT>
+<DD><B>N</B>etwork<B> A</B>ddress<B> T</B>ranslation, a process by which
+ firewall machines may change the addresses on packets as they go
+ through. For discussion, see our<A href="background.html#nat.background">
+ background</A> section.</DD>
+<DT><A name="NIST">NIST</A></DT>
+<DD>The US<A href="http://www.nist.gov"> National Institute of Standards
+ and Technology</A>, responsible for<A href="#FIPS"> FIPS standards</A>
+ including<A href="#DES"> DES</A> and its replacement,<A href="#AES">
+ AES</A>.</DD>
+<DT><A name="nonce">Nonce</A></DT>
+<DD>A<A href="#random"> random</A> value used in an<A href="#authentication">
+ authentication</A> protocol.</DD>
+<DT></DT>
+<DT><A name="non-routable">Non-routable IP address</A></DT>
+<DD>An IP address not normally allowed in the &quot;to&quot; or &quot;from&quot; IP address
+ field header of IP packets.
+<P>Almost invariably, the phrase &quot;non-routable address&quot; means one of the
+ addresses reserved by RFC 1918 for private networks:</P>
+<UL>
+<LI>10.anything</LI>
+<LI>172.x.anything with 16 &lt;= x &lt;= 31</LI>
+<LI>192.168.anything</LI>
+</UL>
+<P>These addresses are commonly used on private networks, e.g. behind a
+ Linux machines doing<A href="#masq"> IP masquerade</A>. Machines within
+ the private network can address each other with these addresses. All
+ packets going outside that network, however, have these addresses
+ replaced before they reach the Internet.</P>
+<P>If any packets using these addresses do leak out, they do not go far.
+ Most routers automatically discard all such packets.</P>
+<P>Various other addresses -- the 127.0.0.0/8 block reserved for local
+ use, 0.0.0.0, various broadcast and network addresses -- cannot be
+ routed over the Internet, but are not normally included in the meaning
+ when the phrase &quot;non-routable address&quot; is used.</P>
+</DD>
+<DT><A name="NSA">NSA</A></DT>
+<DD>The US<A href="http://www.nsa.gov"> National Security Agency</A>,
+ the American organisation for<A href="#SIGINT"> signals intelligence</A>
+, the protection of US government messages and the interception and
+ analysis of other messages. For details, see Bamford's<A href="biblio.html#puzzle">
+ &quot;The Puzzle Palace&quot;</A>.
+<P>Some<A href="http://www.gwu.edu/~nsarchiv/NSAEBB/NSAEBB23/index.html">
+ history of NSA</A> documents were declassified in response to a FOIA
+ (Freedom of Information Act) request.</P>
+</DD>
+<DT><A name="O">O</A></DT>
+<DT><A name="oakley">Oakley</A></DT>
+<DD>A key determination protocol, defined in RFC 2412.</DD>
+<DT>Oakley groups</DT>
+<DD>The groups used as the basis of<A href="#DH"> Diffie-Hellman</A> key
+ exchange in the Oakley protocol, and in<A href="#IKE"> IKE</A>. Four
+ were defined in the original RFC, and a fifth has been<A href="http://www.lounge.org/ike_doi_errata.html">
+ added since</A>.
+<P>Linux FreeS/WAN currently supports the three groups based on finite
+ fields modulo a prime (Groups 1, 2 and 5) and does not support the
+ elliptic curve groups (3 and 4). For a description of the difference of
+ the types, see<A href="#dlog"> discrete logarithms</A>.</P>
+</DD>
+<DT><A name="OTP">One time pad</A></DT>
+<DD>A cipher in which the key is:
+<UL>
+<LI>as long as the total set of messages to be enciphered</LI>
+<LI>absolutely<A href="#random"> random</A></LI>
+<LI>never re-used</LI>
+</UL>
+<P>Given those three conditions, it can easily be proved that the cipher
+ is perfectly secure, in the sense that an attacker with intercepted
+ message in hand has no better chance of guessing the message than an
+ attacker who has not intercepted the message and only knows the message
+ length. No such proof exists for any other cipher.</P>
+<P>There are, however, several problems with this &quot;perfect&quot; cipher.</P>
+<P>First, it is<STRONG> wildly impractical</STRONG> for most
+ applications. Key management is at best difficult, often completely
+ impossible.</P>
+<P>Second, it is<STRONG> extremely fragile</STRONG>. Small changes which
+ violate the conditions listed above do not just weaken the cipher
+ liitle. Quite often they destroy its security completely.</P>
+<UL>
+<LI>Re-using the pad weakens the cipher to the point where it can be
+ broken with pencil and paper. With a computer, the attack is trivially
+ easy.</LI>
+<LI>Using<EM> anything</EM> less than truly<A href="#random"> random</A>
+ numbers<EM> completely</EM> invalidates the security proof.</LI>
+<LI>In particular, using computer-generated pseudo-random numbers may
+ give an extremely weak cipher. It might also produce a good stream
+ cipher, if the pseudo-random generator is both well-designed and
+ properely seeded.</LI>
+</UL>
+<P>Marketing claims about the &quot;unbreakable&quot; security of various products
+ which somewhat resemble one-time pads are common. Such claims are one
+ of the surest signs of cryptographic<A href="#snake"> snake oil</A>;
+ most systems marketed with such claims are worthless.</P>
+<P>Finally, even if the system is implemented and used correctly, it is<STRONG>
+ highly vulnerable to a substitution attack</STRONG>. If an attacker
+ knows some plaintext and has an intercepted message, he can discover
+ the pad.</P>
+<UL>
+<LI>This does not matter if the attacker is just a<A href="#passive">
+ passive</A> eavesdropper. It gives him no plaintext he didn't already
+ know and we don't care that he learns a pad which we will never re-use.</LI>
+<LI>However, an<A href="#active"> active</A> attacker who knows the
+ plaintext can recover the pad, then use it to encode with whatever he
+ chooses. If he can get his version delivered instead of yours, this may
+ be a disaster. If you send &quot;attack at dawn&quot;, the delivered message can
+ be anything the same length -- perhaps &quot;retreat to east&quot; or &quot;shoot
+ generals&quot;.</LI>
+<LI>An active attacker with only a reasonable guess at the plaintext can
+ try the same attack. If the guess is correct, this works and the
+ attacker's bogus message is delivered. If the guess is wrong, a garbled
+ message is delivered.</LI>
+</UL>
+<P>In general then, despite its theoretical perfection, the one-time-pad
+ has very limited practical application.</P>
+<P>See also the<A href="http://pubweb.nfr.net/~mjr/pubs/otpfaq/"> one
+ time pad FAQ</A>.</P>
+</DD>
+<DT><A name="carpediem">Opportunistic encryption (OE)</A></DT>
+<DD>A situation in which any two IPsec-aware machines can secure their
+ communications, without a pre-shared secret and without a common<A href="#PKI">
+ PKI</A> or previous exchange of public keys. This is one of the goals
+ of the Linux FreeS/WAN project, discussed in our<A href="intro.html#goals">
+ introduction</A> section.
+<P>Setting up for opportunistic encryption is described in our<A href="quickstart.html#quickstart">
+ quickstart</A> document.</P>
+</DD>
+<DT><A name="responder">Opportunistic responder</A></DT>
+<DD>A host which accepts, but does not initiate, requests for<A HREF="#carpediem">
+ opportunistic encryption</A> (OE). An opportunistic responder has
+ enabled OE in its<A HREF="#passive.OE"> passive</A> form (pOE) only. A
+ web server or file server may be usefully set up as an opportunistic
+ responder.
+<P>Configuring passive OE is described in our<A href="policygroups.html#policygroups">
+ policy groups</A> document.</P>
+</DD>
+<DT><A name="orange">Orange book</A></DT>
+<DD>the most basic and best known of the US government's<A href="#rainbow">
+ Rainbow Book</A> series of computer security standards.</DD>
+<DT><A name="P">P</A></DT>
+<DT><A name="P1363">P1363 standard</A></DT>
+<DD>An<A href="#IEEE"> IEEE</A> standard for public key cryptography.<A href="http://grouper.ieee.org/groups/1363">
+ Web page</A>.</DD>
+<DT><A name="pOE">pOE</A></DT>
+<DD>See<A href="#passive.OE"> Passive opportunistic encryption</A>.</DD>
+<DT><A name="passive">Passive attack</A></DT>
+<DD>An attack in which the attacker only eavesdrops and attempts to
+ analyse intercepted messages, as opposed to an<A href="#active"> active
+ attack</A> in which he diverts messages or generates his own.</DD>
+<DT><A name="passive.OE">Passive opportunistic encryption (pOE)</A></DT>
+<DD>A form of<A HREF="#carpediem"> opportunistic encryption</A> (OE) in
+ which the host will accept opportunistic connection requests, but will
+ not initiate such requests. A host which runs OE in its passive form
+ only is known as an<A HREF="#responder"> opportunistic responder</A>.
+<P>Configuring passive OE is described in our<A href="policygroups.html#policygroups">
+ policy groups</A> document.</P>
+</DD>
+<DT><A name="pathMTU">Path MTU discovery</A></DT>
+<DD>The process of discovering the largest packet size which all links
+ on a path can handle without fragmentation -- that is, without any
+ router having to break the packet up into smaller pieces to match the<A href="#MTU">
+ MTU</A> of its outgoing link.
+<P>This is done as follows:</P>
+<UL>
+<LI>originator sends the largest packets allowed by<A href="#MTU"> MTU</A>
+ of the first link, setting the DF (<STRONG>d</STRONG>on't<STRONG> f</STRONG>
+ragment) bit in the packet header</LI>
+<LI>any router which cannot send the packet on (outgoing MTU is too
+ small for it, and DF prevents fragmenting it to match) sends back an<A href="#ICMP.gloss">
+ ICMP</A> packet reporting the problem</LI>
+<LI>originator looks at ICMP message and tries a smaller size</LI>
+<LI>eventually, you settle on a size that can pass all routers</LI>
+<LI>thereafter, originator just sends that size and no-one has to
+ fragment</LI>
+</UL>
+<P>Since this requires co-operation of many systems, and since the next
+ packet may travel a different path, this is one of the trickier areas
+ of IP programming. Bugs that have shown up over the years have
+ included:</P>
+<UL>
+<LI>malformed ICMP messages</LI>
+<LI>hosts that ignore or mishandle these ICMP messages</LI>
+<LI>firewalls blocking the ICMP messages so host does not see them</LI>
+</UL>
+<P>Since IPsec adds a header, it increases packet size and may require
+ fragmentation even where incoming and outgoing MTU are equal.</P>
+</DD>
+<DT><A name="PFS">Perfect forward secrecy (PFS)</A></DT>
+<DD>A property of systems such as<A href="#DH"> Diffie-Hellman</A> key
+ exchange which use a long-term key (such as the shared secret in IKE)
+ and generate short-term keys as required. If an attacker who acquires
+ the long-term key<EM> provably</EM> can
+<UL>
+<LI><EM>neither</EM> read previous messages which he may have archived</LI>
+<LI><EM>nor</EM> read future messages without performing additional
+ successful attacks</LI>
+</UL>
+<P>then the system has PFS. The attacker needs the short-term keys in
+ order to read the trafiic and merely having the long-term key does not
+ allow him to infer those. Of course, it may allow him to conduct
+ another attack (such as<A href="#middle"> man-in-the-middle</A>) which
+ gives him some short-term keys, but he does not automatically get them
+ just by acquiring the long-term key.</P>
+<P>See also<A href="http://sandelman.ottawa.on.ca/ipsec/1996/08/msg00123.html">
+ Phil Karn's definition</A>.</P>
+</DD>
+<DT>PFS</DT>
+<DD>see Perfect Forward Secrecy</DD>
+<DT><A name="PGP">PGP</A></DT>
+<DD><B>P</B>retty<B> G</B>ood<B> P</B>rivacy, a personal encryption
+ system for email based on public key technology, written by Phil
+ Zimmerman.
+<P>The 2.xx versions of PGP used the<A href="#RSA"> RSA</A> public key
+ algorithm and used<A href="#IDEA"> IDEA</A> as the symmetric cipher.
+ These versions are described in RFC 1991 and in<A href="#PGP">
+ Garfinkel's book</A>. Since version 5, the products from<A href="#PGPI">
+ PGP Inc</A>. have used<A href="#DH"> Diffie-Hellman</A> public key
+ methods and<A href="#CAST128"> CAST-128</A> symmetric encryption. These
+ can verify signatures from the 2.xx versions, but cannot exchange
+ encryted messages with them.</P>
+<P>An<A href="mail.html#IETF"> IETF</A> working group has issued RFC
+ 2440 for an &quot;Open PGP&quot; standard, similar to the 5.x versions. PGP Inc.
+ staff were among the authors. A free<A href="#GPG"> Gnu Privacy Guard</A>
+ based on that standard is now available.</P>
+<P>For more information on PGP, including how to obtain it, see our
+ cryptography<A href="web.html#tools"> links</A>.</P>
+</DD>
+<DT><A name="PGPI">PGP Inc.</A></DT>
+<DD>A company founded by Zimmerman, the author of<A href="#PGP"> PGP</A>
+, now a division of<A href="#NAI"> NAI</A>. See the<A href="http://www.pgp.com">
+ corporate website</A>. Zimmerman left in 2001, and early in 2002 NAI
+ announced that they would no longer sell PGP..
+<P>Versions 6.5 and later of the PGP product include PGPnet, an IPsec
+ client for Macintosh or for Windows 95/98/NT. See our<A href="interop.html#pgpnet">
+ interoperation documen</A>t.</P>
+</DD>
+<DT><A name="photuris">Photuris</A></DT>
+<DD>Another key negotiation protocol, an alternative to<A href="#IKE">
+ IKE</A>, described in RFCs 2522 and 2523.</DD>
+<DT><A name="PPP">PPP</A></DT>
+<DD><B>P</B>oint-to-<B>P</B>oint<B> P</B>rotocol, originally a method of
+ connecting over modems or serial lines, but see also PPPoE.</DD>
+<DT><A name="PPPoE">PPPoE</A></DT>
+<DD><B>PPP</B><B> o</B>ver<B> E</B>thernet, a somewhat odd protocol that
+ makes Ethernet look like a point-to-point serial link. It is widely
+ used for cable or ADSL Internet services, apparently mainly because it
+ lets the providers use access control and address assignmment
+ mechanisms developed for dialup networks.<A href="http://www.roaringpenguin.com">
+ Roaring Penguin</A> provide a widely used Linux implementation.</DD>
+<DT><A name="PPTP">PPTP</A></DT>
+<DD><B>P</B>oint-to-<B>P</B>oint<B> T</B>unneling<B> P</B>rotocol, used
+ in some Microsoft VPN implementations. Papers discussing weaknesses in
+ it are on<A href="http://www.counterpane.com/publish.html">
+ counterpane.com</A>. It is now largely obsolete, replaced by L2TP.</DD>
+<DT><A name="PKI">PKI</A></DT>
+<DD><B>P</B>ublic<B> K</B>ey<B> I</B>nfrastructure, the things an
+ organisation or community needs to set up in order to make<A href="#public">
+ public key</A> cryptographic technology a standard part of their
+ operating procedures.
+<P>There are several PKI products on the market. Typically they use a
+ hierarchy of<A href="#CA"> Certification Authorities (CAs)</A>. Often
+ they use<A href="#LDAP"> LDAP</A> access to<A href="#X509"> X.509</A>
+ directories to implement this.</P>
+<P>See<A href="#web"> Web of Trust</A> for a different sort of
+ infrastructure.</P>
+</DD>
+<DT><A name="PKIX">PKIX</A></DT>
+<DD><B>PKI</B> e<B>X</B>change, an<A href="mail.html#IETF"> IETF</A>
+ standard that allows<A href="#PKI"> PKI</A>s to talk to each other.
+<P>This is required, for example, when users of a corporate PKI need to
+ communicate with people at client, supplier or government
+ organisations, any of which may have a different PKI in place. I should
+ be able to talk to you securely whenever:</P>
+<UL>
+<LI>your organisation and mine each have a PKI in place</LI>
+<LI>you and I are each set up to use those PKIs</LI>
+<LI>the two PKIs speak PKIX</LI>
+<LI>the configuration allows the conversation</LI>
+</UL>
+<P>At time of writing (March 1999), this is not yet widely implemented
+ but is under quite active development by several groups.</P>
+</DD>
+<DT><A name="plaintext">Plaintext</A></DT>
+<DD>The unencrypted input to a cipher, as opposed to the encrypted<A href="#ciphertext">
+ ciphertext</A> output.</DD>
+<DT><A name="Pluto">Pluto</A></DT>
+<DD>The<A href="web.html#FreeSWAN"> Linux FreeS/WAN</A> daemon which
+ handles key exchange via the<A href="#IKE"> IKE</A> protocol,
+ connection negotiation, and other higher-level tasks. Pluto calls the<A href="#KLIPS">
+ KLIPS</A> kernel code as required. For details, see the manual page
+ ipsec_pluto(8).</DD>
+<DT><A name="public">Public Key Cryptography</A></DT>
+<DD>In public key cryptography, keys are created in matched pairs.
+ Encrypt with one half of a pair and only the matching other half can
+ decrypt it. This contrasts with<A href="#symmetric"> symmetric or
+ secret key cryptography</A> in which a single key known to both parties
+ is used for both encryption and decryption.
+<P>One half of each pair, called the public key, is made public. The
+ other half, called the private key, is kept secret. Messages can then
+ be sent by anyone who knows the public key to the holder of the private
+ key. Encrypt with the public key and you know that only someone with
+ the matching private key can decrypt.</P>
+<P>Public key techniques can be used to create<A href="#signature">
+ digital signatures</A> and to deal with key management issues, perhaps
+ the hardest part of effective deployment of<A href="#symmetric">
+ symmetric ciphers</A>. The resulting<A href="#hybrid"> hybrid
+ cryptosystems</A> use public key methods to manage keys for symmetric
+ ciphers.</P>
+<P>Many organisations are currently creating<A href="#PKI"> PKIs, public
+ key infrastructures</A> to make these benefits widely available.</P>
+</DD>
+<DT>Public Key Infrastructure</DT>
+<DD>see<A href="#PKI"> PKI</A></DD>
+<DT><A name="Q">Q</A></DT>
+<DT><A name="R">R</A></DT>
+<DT><A name="rainbow">Rainbow books</A></DT>
+<DD>A set of US government standards for evaluation of &quot;trusted computer
+ systems&quot;, of which the best known was the<A href="#orange"> Orange Book</A>
+. One fairly often hears references to &quot;C2 security&quot; or a product
+ &quot;evaluated at B1&quot;. The Rainbow books define the standards referred to
+ in those comments.
+<P>See this<A href="http://www.fas.org/irp/nsa/rainbow.htm"> reference
+ page</A>.</P>
+<P>The Rainbow books are now mainly obsolete, replaced by the
+ international<A href="#cc"> Common Criteria</A> standards.</P>
+</DD>
+<DT><A name="random">Random</A></DT>
+<DD>A remarkably tricky term, far too much so for me to attempt a
+ definition here. Quite a few cryptosystems have been broken via attacks
+ on weak random number generators, even when the rest of the system was
+ sound.
+<P>See<A href="http://nis.nsf.net/internet/documents/rfc/rfc1750.txt">
+ RFC 1750</A> for the theory.</P>
+<P>See the manual pages for<A href="manpage.d/ipsec_ranbits.8.html">
+ ipsec_ranbits(8)</A> and ipsec_prng(3) for more on FreeS/WAN's use of
+ randomness. Both depend on the random(4) device driver..</P>
+<P>A couple of years ago, there was extensive mailing list discussion
+ (archived<A href="http://www.openpgp.net/random/index.html"> here</A>
+)of Linux /dev/random and FreeS/WAN. Since then, the design of the
+ random(4) driver has changed considerably. Linux 2.4 kernels have the
+ new driver..</P>
+</DD>
+<DT>Raptor</DT>
+<DD>A firewall product for Windows NT offerring IPsec-based VPN
+ services. Linux FreeS/WAN interoperates with Raptor; see our<A href="interop.html#Raptor">
+ interop</A> document for details. Raptor have recently merged with
+ Axent.</DD>
+<DT><A name="RC4">RC4</A></DT>
+<DD><B>R</B>ivest<B> C</B>ipher four, designed by Ron Rivest of<A href="#RSAco">
+ RSA</A> and widely used. Believed highly secure with adequate key
+ length, but often implemented with inadequate key length to comply with
+ export restrictions.</DD>
+<DT><A name="RC6">RC6</A></DT>
+<DD><B>R</B>ivest<B> C</B>ipher six,<A href="#RSAco"> RSA</A>'s<A href="#AES">
+ AES</A> candidate cipher.</DD>
+<DT><A name="replay">Replay attack</A></DT>
+<DD>An attack in which the attacker records data and later replays it in
+ an attempt to deceive the recipient.</DD>
+<DT><A name="reverse">Reverse map</A></DT>
+<DD>In<A href="ipsec.html#DNS"> DNS</A>, a table where IP addresses can
+ be used as the key for lookups which return a system name and/or other
+ information.</DD>
+<DT>RFC</DT>
+<DD><B>R</B>equest<B> F</B>or<B> C</B>omments, an Internet document.
+ Some RFCs are just informative. Others are standards.
+<P>Our list of<A href="#IPSEC"> IPsec</A> and other security-related
+ RFCs is<A href="rfc.html#RFC"> here</A>, along with information on
+ methods of obtaining them.</P>
+</DD>
+<DT><A name="rijndael">Rijndael</A></DT>
+<DD>a<A href="#block"> block cipher</A> designed by two Belgian
+ cryptographers, winner of the US government's<A href="#AES"> AES</A>
+ contest to pick a replacement for<A href="#DES"> DES</A>. See the<A href="http://www.esat.kuleuven.ac.be/~rijmen/rijndael">
+ Rijndael home page</A>.</DD>
+<DT><A name="RIPEMD">RIPEMD</A></DT>
+<DD>A<A href="#digest"> message digest</A> algorithm. The current
+ version is RIPEMD-160 which gives a 160-bit hash.</DD>
+<DT><A name="rootCA">Root CA</A></DT>
+<DD>The top level<A href="#CA"> Certification Authority</A> in a
+ hierachy of such authorities.</DD>
+<DT><A name="routable">Routable IP address</A></DT>
+<DD>Most IP addresses can be used as &quot;to&quot; and &quot;from&quot; addresses in packet
+ headers. These are the routable addresses; we expect routing to be
+ possible for them. If we send a packet to one of them, we expect (in
+ most cases; there are various complications) that it will be delivered
+ if the address is in use and will cause an<A href="#ICMP.gloss"> ICMP</A>
+ error packet to come back to us if not.
+<P>There are also several classes of<A href="#non-routable">
+ non-routable</A> IP addresses.</P>
+</DD>
+<DT><A name="RSA">RSA algorithm</A></DT>
+<DD><B>R</B>ivest<B> S</B>hamir<B> A</B>dleman<A href="#public"> public
+ key</A> algorithm, named for its three inventors. It is widely used and
+ likely to become moreso since it became free of patent encumbrances in
+ September 2000.
+<P>RSA can be used to provide either<A href="#encryption"> encryption</A>
+ or<A href="#signature"> digital signatures</A>. In IPsec, it is used
+ only for signatures. These provide gateway-to-gateway<A href="#authentication">
+ authentication</A> for<A href="#IKE"> IKE</A> negotiations.</P>
+<P>For a full explanation of the algorithm, consult one of the standard
+ references such as<A href="biblio.html#schneier"> Applied Cryptography</A>
+. A simple explanation is:</P>
+<P>The great 17th century French mathematician<A href="http://www-groups.dcs.st-andrews.ac.uk/~history/Mathematicians/Fermat.html">
+ Fermat</A> proved that,</P>
+<P>for any prime p and number x, 0 &lt;= x &lt; p:</P>
+<PRE>        x^p == x         modulo p
+        x^(p-1) == 1     modulo p, non-zero x
+      </PRE>
+<P>From this it follows that if we have a pair of primes p, q and two
+ numbers e, d such that:</P>
+<PRE>        ed == 1          modulo lcm( p-1, q-1)
+      </PRE>
+ where lcm() is least common multiple, then
+<BR> for all x, 0 &lt;= x &lt; pq:
+<PRE>      x^ed == x           modulo pq
+      </PRE>
+<P>So we construct such as set of numbers p, q, e, d and publish the
+ product N=pq and e as the public key. Using c for<A href="#ciphertext">
+ ciphertext</A> and i for the input<A href="#plaintext"> plaintext</A>,
+ encryption is then:</P>
+<PRE>        c = i^e           modulo N
+      </PRE>
+<P>An attacker cannot deduce i from the cyphertext c, short of either
+ factoring N or solving the<A href="#dlog"> discrete logarithm</A>
+ problem for this field. If p, q are large primes (hundreds or thousands
+ of bits) no efficient solution to either problem is known.</P>
+<P>The receiver, knowing the private key (N and d), can readily recover
+ the plaintext p since:</P>
+<PRE>        c^d == (i^e)^d    modulo N
+            == i^ed       modulo N
+            == i          modulo N
+      </PRE>
+<P>This gives an effective public key technique, with only a couple of
+ problems. It uses a good deal of computer time, since calculations with
+ large integers are not cheap, and there is no proof it is necessarily
+ secure since no-one has proven either factoring or discrete log cannot
+ be done efficiently. Quite a few good mathematicians have tried both
+ problems, and no-one has announced success, but there is no proof they
+ are insoluble.</P>
+</DD>
+<DT><A name="RSAco">RSA Data Security</A></DT>
+<DD>A company founded by the inventors of the<A href="#RSA"> RSA</A>
+ public key algorithm.</DD>
+<DT><A name="S">S</A></DT>
+<DT><A name="SA">SA</A></DT>
+<DD><B>S</B>ecurity<B> A</B>ssociation, the channel negotiated by the
+ higher levels of an<A href="#IPSEC"> IPsec</A> implementation (<A href="#IKE">
+IKE</A>) and used by the lower (<A href="#ESP">ESP</A> and<A href="#AH">
+ AH</A>). SAs are unidirectional; you need a pair of them for two-way
+ communication.
+<P>An SA is defined by three things -- the destination, the protocol (<A href="#AH">
+AH</A> or<A href="#ESP">ESP</A>) and the<A href="SPI"> SPI</A>, security
+ parameters index. It is used as an index to look up other things such
+ as session keys and intialisation vectors.</P>
+<P>For more detail, see our section on<A href="ipsec.html"> IPsec</A>
+ and/or RFC 2401.</P>
+</DD>
+<DT><A name="SElinux">SE Linux</A></DT>
+<DD><STRONG>S</STRONG>ecurity<STRONG> E</STRONG>nhanced Linux, an<A href="#NSA">
+ NSA</A>-funded project to add<A href="#mandatory"> mandatory access
+ control</A> to Linux. See the<A href="http://www.nsa.gov/selinux">
+ project home page</A>.
+<P>According to their web pages, this work will include extending
+ mandatory access controls to IPsec tunnels.</P>
+<P>Recent versions of SE Linux code use the<A href="#LSM"> Linux
+ Security Module</A> interface.</P>
+</DD>
+<DT><A name="SDNS">Secure DNS</A></DT>
+<DD>A version of the<A href="ipsec.html#DNS"> DNS or Domain Name Service</A>
+ enhanced with authentication services. This is being designed by the<A href="mail.html#IETF">
+ IETF</A> DNS security<A href="http://www.ietf.org/ids.by.wg/dnssec.html">
+ working group</A>. Check the<A href="http://www.isc.org/bind.html">
+ Internet Software Consortium</A> for information on implementation
+ progress and for the latest version of<A href="#BIND"> BIND</A>.
+ Another site has<A href="http://www.toad.com/~dnssec"> more information</A>
+.
+<P><A href="#IPSEC">IPsec</A> can use this plus<A href="#DH">
+ Diffie-Hellman key exchange</A> to bootstrap itself. This allows<A href="#carpediem">
+ opportunistic encryption</A>. Any pair of machines which can
+ authenticate each other via DNS can communicate securely, without
+ either a pre-existing shared secret or a shared<A href="#PKI"> PKI</A>.</P>
+</DD>
+<DT>Secret key cryptography</DT>
+<DD>See<A href="#symmetric"> symmetric cryptography</A></DD>
+<DT>Security Association</DT>
+<DD>see<A href="#SA"> SA</A></DD>
+<DT>Security Enhanced Linux</DT>
+<DD>see<A href="#SElinux"> SE Linux</A></DD>
+<DT><A name="sequence">Sequence number</A></DT>
+<DD>A number added to a packet or message which indicates its position
+ in a sequence of packets or messages. This provides some security
+ against<A href="#replay"> replay attacks</A>.
+<P>For<A href="ipsec.html#auto"> automatic keying</A> mode, the<A href="#IPSEC">
+ IPsec</A> RFCs require that the sender generate sequence numbers for
+ each packet, but leave it optional whether the receiver does anything
+ with them.</P>
+</DD>
+<DT><A name="SHA">SHA</A></DT>
+<DT>SHA-1</DT>
+<DD><B>S</B>ecure<B> H</B>ash<B> A</B>lgorithm, a<A href="#digest">
+ message digest algorithm</A> developed by the<A href="#NSA"> NSA</A>
+ for use in the Digital Signature standard,<A href="#FIPS"> FIPS</A>
+ number 186 from<A href="#NIST"> NIST</A>. SHA is an improved variant of<A
+href="#MD4"> MD4</A> producing a 160-bit hash.
+<P>SHA is one of two message digest algorithms available in IPsec. The
+ other is<A href="#MD5"> MD5</A>. Some people do not trust SHA because
+ it was developed by the<A href="#NSA"> NSA</A>. There is, as far as we
+ know, no cryptographic evidence that SHA is untrustworthy, but this
+ does not prevent that view from being strongly held.</P>
+<P>The NSA made one small change after the release of the original SHA.
+ They did not give reasons. Iit may be a defense against some attack
+ they found and do not wish to disclose. Technically the modified
+ algorithm should be called SHA-1, but since it has replaced the
+ original algorithm in nearly all applications, it is generally just
+ referred to as SHA..</P>
+</DD>
+<DT><A name="SHA-256">SHA-256</A></DT>
+<DT>SHA-384</DT>
+<DT>SHA-512</DT>
+<DD>Newer variants of SHA designed to match the strength of the 128, 192
+ and 256-bit keys of<A href="#AES"> AES</A>. The work to break an
+ encryption algorithm's strength by<A href="#brute"> brute force</A> is
+ 2
+<!--math xmlns="http://www.w3.org/1998/Math/MathML"-->
+
+<!--msup-->
+
+<!--mi-->
+ keylength</(null)></(null)></(null)> operations but a<A href="birthday">
+ birthday attack</A> on a hash needs only 2
+<!--math xmlns="http://www.w3.org/1998/Math/MathML"-->
+
+<!--msup-->
+
+<!--mrow-->
+
+<!--mi-->
+ hashlength</(null)>
+<!--mo-->
+ /</(null)>
+<!--mn-->
+
+ 2</(null)></(null)></(null)></(null)> , so as a general rule you need a
+ hash twice the size of the key to get similar strength. SHA-256,
+ SHA-384 and SHA-512 are designed to match the 128, 192 and 256-bit key
+ sizes of AES, respectively.</DD>
+<DT><A name="SIGINT">Signals intelligence (SIGINT)</A></DT>
+<DD>Activities of government agencies from various nations aimed at
+ protecting their own communications and reading those of others.
+ Cryptography, cryptanalysis, wiretapping, interception and monitoring
+ of various sorts of signals. The players include the American<A href="#NSA">
+ NSA</A>, British<A href="#GCHQ"> GCHQ</A> and Canadian<A href="#CSE">
+ CSE</A>.</DD>
+<DT><A name="SKIP">SKIP</A></DT>
+<DD><B>S</B>imple<B> K</B>ey management for<B> I</B>nternet<B> P</B>
+rotocols, an alternative to<A href="#IKE"> IKE</A> developed by Sun and
+ being marketed by their<A href="http://skip.incog.com"> Internet
+ Commerce Group</A>.</DD>
+<DT><A name="snake">Snake oil</A></DT>
+<DD>Bogus cryptography. See the<A href="http://www.interhack.net/people/cmcurtin/snake-oil-faq.html">
+ Snake Oil FAQ</A> or<A href="http://www.counterpane.com/crypto-gram-9902.html#snakeoil">
+ this paper</A> by Schneier.</DD>
+<DT><A name="SPI">SPI</A></DT>
+<DD><B>S</B>ecurity<B> P</B>arameter<B> I</B>ndex, an index used within<A
+href="#IPSEC"> IPsec</A> to keep connections distinct. A<A href="#SA">
+ Security Association (SA)</A> is defined by destination, protocol and
+ SPI. Without the SPI, two connections to the same gateway using the
+ same protocol could not be distinguished.
+<P>For more detail, see our<A href="ipsec.html"> IPsec</A> section
+ and/or RFC 2401.</P>
+</DD>
+<DT><A name="SSH">SSH</A></DT>
+<DD><B>S</B>ecure<B> SH</B>ell, an encrypting replacement for the
+ insecure Berkeley commands whose names begin with &quot;r&quot; for &quot;remote&quot;:
+ rsh, rlogin, etc.
+<P>For more information on SSH, including how to obtain it, see our
+ cryptography<A href="web.html#tools"> links</A>.</P>
+</DD>
+<DT><A name="SSHco">SSH Communications Security</A></DT>
+<DD>A company founded by the authors of<A href="#SSH"> SSH</A>. Offices
+ are in<A href="http://www.ssh.fi"> Finland</A> and<A href="http://www.ipsec.com">
+ California</A>. They have a toolkit for developers of IPsec
+ applications.</DD>
+<DT><A name="SSL">SSL</A></DT>
+<DD><A href="http://home.netscape.com/eng/ssl3">Secure Sockets Layer</A>
+, a set of encryption and authentication services for web browsers,
+ developed by Netscape. Widely used in Internet commerce. Also known as<A
+href="#TLS"> TLS</A>.</DD>
+<DT>SSLeay</DT>
+<DD>A free implementation of<A href="#SSL"> SSL</A> by Eric Young (eay)
+ and others. Developed in Australia; not subject to US export controls.</DD>
+<DT><A name="static">static IP address</A></DT>
+<DD>an IP adddress which is pre-set on the machine itself, as opposed to
+ a<A href="#dynamic"> dynamic address</A> which is assigned by a<A href="#DHCP">
+ DHCP</A> server or obtained as part of the process of establishing a<A href="#PPP">
+ PPP</A> or<A href="#PPPoE"> PPPoE</A> connection</DD>
+<DT><A name="stream">Stream cipher</A></DT>
+<DD>A<A href="#symmetric"> symmetric cipher</A> which produces a stream
+ of output which can be combined (often using XOR or bytewise addition)
+ with the plaintext to produce ciphertext. Contrasts with<A href="#block">
+ block cipher</A>.
+<P><A href="#IPSEC">IPsec</A> does not use stream ciphers. Their main
+ application is link-level encryption, for example of voice, video or
+ data streams on a wire or a radio signal.</P>
+</DD>
+<DT><A name="subnet">subnet</A></DT>
+<DD>A group of IP addresses which are logically one network, typically
+ (but not always) assigned to a group of physically connected machines.
+ The range of addresses in a subnet is described using a subnet mask.
+ See next entry.</DD>
+<DT>subnet mask</DT>
+<DD>A method of indicating the addresses included in a subnet. Here are
+ two equivalent examples:
+<UL>
+<LI>101.101.101.0/24</LI>
+<LI>101.101.101.0 with mask 255.255.255.0</LI>
+</UL>
+<P>The '24' is shorthand for a mask with the top 24 bits one and the
+ rest zero. This is exactly the same as 255.255.255.0 which has three
+ all-ones bytes and one all-zeros byte.</P>
+<P>These indicate that, for this range of addresses, the top 24 bits are
+ to be treated as naming a network (often referred to as &quot;the
+ 101.101.101.0/24 subnet&quot;) while most combinations of the low 8 bits can
+ be used to designate machines on that network. Two addresses are
+ reserved; 101.101.101.0 refers to the subnet rather than a specific
+ machine while 101.101.101.255 is a broadcast address. 1 to 254 are
+ available for machines.</P>
+<P>It is common to find subnets arranged in a hierarchy. For example, a
+ large company might have a /16 subnet and allocate /24 subnets within
+ that to departments. An ISP might have a large subnet and allocate /26
+ subnets (64 addresses, 62 usable) to business customers and /29 subnets
+ (8 addresses, 6 usable) to residential clients.</P>
+</DD>
+<DT><A name="SWAN">S/WAN</A></DT>
+<DD>Secure Wide Area Network, a project involving<A href="#RSAco"> RSA
+ Data Security</A> and a number of other companies. The goal was to
+ ensure that all their<A href="#IPSEC"> IPsec</A> implementations would
+ interoperate so that their customers can communicate with each other
+ securely.</DD>
+<DT><A name="symmetric">Symmetric cryptography</A></DT>
+<DD>Symmetric cryptography, also referred to as conventional or secret
+ key cryptography, relies on a<EM> shared secret key</EM>, identical for
+ sender and receiver. Sender encrypts with that key, receiver decrypts
+ with it. The idea is that an eavesdropper without the key be unable to
+ read the messages. There are two main types of symmetric cipher,<A href="#block">
+ block ciphers</A> and<A href="#stream"> stream ciphers</A>.
+<P>Symmetric cryptography contrasts with<A href="#public"> public key</A>
+ or asymmetric systems where the two players use different keys.</P>
+<P>The great difficulty in symmetric cryptography is, of course, key
+ management. Sender and receiver<EM> must</EM> have identical keys and
+ those keys<EM> must</EM> be kept secret from everyone else. Not too
+ much of a problem if only two people are involved and they can
+ conveniently meet privately or employ a trusted courier. Quite a
+ problem, though, in other circumstances.</P>
+<P>It gets much worse if there are many people. An application might be
+ written to use only one key for communication among 100 people, for
+ example, but there would be serious problems. Do you actually trust all
+ of them that much? Do they trust each other that much? Should they?
+ What is at risk if that key is compromised? How are you going to
+ distribute that key to everyone without risking its secrecy? What do
+ you do when one of them leaves the company? Will you even know?</P>
+<P>On the other hand, if you need unique keys for every possible
+ connection between a group of 100, then each user must have 99 keys.
+ You need either 99*100/2 = 4950<EM> secure</EM> key exchanges between
+ users or a central authority that<EM> securely</EM> distributes 100 key
+ packets, each with a different set of 99 keys.</P>
+<P>Either of these is possible, though tricky, for 100 users. Either
+ becomes an administrative nightmare for larger numbers. Moreover, keys<EM>
+ must</EM> be changed regularly, so the problem of key distribution
+ comes up again and again. If you use the same key for many messages
+ then an attacker has more text to work with in an attempt to crack that
+ key. Moreover, one successful crack will give him or her the text of
+ all those messages.</P>
+<P>In short, the<EM> hardest part of conventional cryptography is key
+ management</EM>. Today the standard solution is to build a<A href="#hybrid">
+ hybrid system</A> using<A href="#public"> public key</A> techniques to
+ manage keys.</P>
+</DD>
+<DT><A name="T">T</A></DT>
+<DT><A name="TIS">TIS</A></DT>
+<DD>Trusted Information Systems, a firewall vendor now part of<A href="#NAI">
+ NAI</A>. Their Gauntlet product offers IPsec VPN services. TIS
+ implemented the first version of<A href="#SDNS"> Secure DNS</A> on a<A href="#DARPA">
+ DARPA</A> contract.</DD>
+<DT><A name="TLS">TLS</A></DT>
+<DD><B>T</B>ransport<B> L</B>ayer<B> S</B>ecurity, a newer name for<A href="#SSL">
+ SSL</A>.</DD>
+<DT><A name="TOS">TOS field</A></DT>
+<DD>The<STRONG> T</STRONG>ype<STRONG> O</STRONG>f<STRONG> S</STRONG>
+ervice field in an IP header, used to control qualkity of service
+ routing.</DD>
+<DT><A name="traffic">Traffic analysis</A></DT>
+<DD>Deducing useful intelligence from patterns of message traffic,
+ without breaking codes or reading the messages. In one case during
+ World War II, the British guessed an attack was coming because all
+ German radio traffic stopped. The &quot;radio silence&quot; order, intended to
+ preserve security, actually gave the game away.
+<P>In an industrial espionage situation, one might deduce something
+ interesting just by knowing that company A and company B were talking,
+ especially if one were able to tell which departments were involved, or
+ if one already knew that A was looking for acquisitions and B was
+ seeking funds for expansion.</P>
+<P>In general, traffic analysis by itself is not very useful. However,
+ in the context of a larger intelligence effort where quite a bit is
+ already known, it can be very useful. When you are solving a complex
+ puzzle, every little bit helps.</P>
+<P><A href="#IPSEC">IPsec</A> itself does not defend against traffic
+ analysis, but carefully thought out systems using IPsec can provide at
+ least partial protection. In particular, one might want to encrypt more
+ traffic than was strictly necessary, route things in odd ways, or even
+ encrypt dummy packets, to confuse the analyst. We discuss this<A href="ipsec.html#traffic.resist">
+ here</A>.</P>
+</DD>
+<DT><A name="transport">Transport mode</A></DT>
+<DD>An IPsec application in which the IPsec gateway is the destination
+ of the protected packets, a machine acts as its own gateway. Contrast
+ with<A href="#tunnel"> tunnel mode</A>.</DD>
+<DT>Triple DES</DT>
+<DD>see<A href="#3DES"> 3DES</A></DD>
+<DT><A name="TTL">TTL</A></DT>
+<DD><STRONG>T</STRONG>ime<STRONG> T</STRONG>o<STRONG> L</STRONG>ive,
+ used to control<A href="ipsec.html#DNS"> DNS</A> caching. Servers
+ discard cached records whose TTL expires</DD>
+<DT><A name="tunnel">Tunnel mode</A></DT>
+<DD>An IPsec application in which an IPsec gateway provides protection
+ for packets to and from other systems. Contrast with<A href="#transport">
+ transport mode</A>.</DD>
+<DT><A name="2key">Two-key Triple DES</A></DT>
+<DD>A variant of<A href="#3DES"> triple DES or 3DES</A> in which only
+ two keys are used. As in the three-key version, the order of operations
+ is<A href="#EDE"> EDE</A> or encrypt-decrypt-encrypt, but in the
+ two-key variant the first and third keys are the same.
+<P>3DES with three keys has 3*56 = 168 bits of key but has only 112-bit
+ strength against a<A href="#meet"> meet-in-the-middle</A> attack, so it
+ is possible that the two key version is just as strong. Last I looked,
+ this was an open question in the research literature.</P>
+<P>RFC 2451 defines triple DES for<A href="#IPSEC"> IPsec</A> as the
+ three-key variant. The two-key variant should not be used and is not
+ implemented directly in<A href="web.html#FreeSWAN"> Linux FreeS/WAN</A>
+. It cannot be used in automatically keyed mode without major fiddles in
+ the source code. For manually keyed connections, you could make Linux
+ FreeS/WAN talk to a two-key implementation by setting two keys the same
+ in /etc/ipsec.conf.</P>
+</DD>
+<DT><A name="U">U</A></DT>
+<DT><A name="V">V</A></DT>
+<DT><A name="virtual">Virtual Interface</A></DT>
+<DD>A<A href="#Linux"> Linux</A> feature which allows one physical
+ network interface to have two or more IP addresses. See the<CITE> Linux
+ Network Administrator's Guide</CITE> in<A href="biblio.html#kirch">
+ book form</A> or<A href="http://metalab.unc.edu/LDP/LDP/nag/node1.html">
+ on the web</A> for details.</DD>
+<DT>Virtual Private Network</DT>
+<DD>see<A href="#VPN"> VPN</A></DD>
+<DT><A name="VPN">VPN</A></DT>
+<DD><B>V</B>irtual<B> P</B>rivate<B> N</B>etwork, a network which can
+ safely be used as if it were private, even though some of its
+ communication uses insecure connections. All traffic on those
+ connections is encrypted.
+<P><A href="#IPSEC">IPsec</A> is not the only technique available for
+ building VPNs, but it is the only method defined by<A href="rfc.html#RFC">
+ RFCs</A> and supported by many vendors. VPNs are by no means the only
+ thing you can do with IPsec, but they may be the most important
+ application for many users.</P>
+</DD>
+<DT><A name="VPNC">VPNC</A></DT>
+<DD><A href="http://www.vpnc.org">Virtual Private Network Consortium</A>
+, an association of vendors of VPN products.</DD>
+<DT><A name="W">W</A></DT>
+<DT><A name="Wassenaar.gloss">Wassenaar Arrangement</A></DT>
+<DD>An international agreement restricting export of munitions and other
+ tools of war. Unfortunately, cryptographic software is also restricted
+ under the current version of the agreement.<A href="politics.html#Wassenaar">
+ Discussion</A>.</DD>
+<DT><A name="web">Web of Trust</A></DT>
+<DD><A href="#PGP">PGP</A>'s method of certifying keys. Any user can
+ sign a key; you decide which signatures or combinations of signatures
+ to accept as certification. This contrasts with the hierarchy of<A href="#CA">
+ CAs (Certification Authorities)</A> used in many<A href="#PKI"> PKIs
+ (Public Key Infrastructures)</A>.
+<P>See<A href="#GTR"> Global Trust Register</A> for an interesting
+ addition to the web of trust.</P>
+</DD>
+<DT><A name="WEP">WEP (Wired Equivalent Privacy)</A></DT>
+<DD>The cryptographic part of the<A href="#IEEE"> IEEE</A> standard for
+ wireless LANs. As the name suggests, this is designed to be only as
+ secure as a normal wired ethernet. Anyone with a network conection can
+ tap it. Its advocates would claim this is good design, refusing to
+ build in complex features beyond the actual requirements.
+<P>Critics refer to WEP as &quot;Wire<EM>tap</EM> Equivalent Privacy&quot;, and
+ consider it a horribly flawed design based on bogus &quot;requirements&quot;. You
+ do not control radio waves as you might control your wires, so the
+ metaphor in the rationale is utterly inapplicable. A security policy
+ that chooses not to invest resources in protecting against certain
+ attacks which can only be conducted by people physically plugged into
+ your LAN may or may not be reasonable. The same policy is completely
+ unreasonable when someone can &quot;plug in&quot; from a laptop half a block
+ away..</P>
+<P>There has been considerable analysis indicating that WEP is seriously
+ flawed. A FAQ on attacks against WEP is available. Part of it reads:</P>
+<BLOCKQUOTE> ... attacks are practical to mount using only inexpensive
+ off-the-shelf equipment. We recommend that anyone using an 802.11
+ wireless network not rely on WEP for security, and employ other
+ security measures to protect their wireless network. Note that our
+ attacks apply to both 40-bit and the so-called 128-bit versions of WEP
+ equally well.</BLOCKQUOTE>
+<P>WEP appears to be yet another instance of governments, and
+ unfortunately some vendors and standards bodies, deliberately promoting
+ hopelessly flawed &quot;security&quot; products, apparently mainly for the
+ benefit of eavesdropping agencies. See this<A href="politics.html#weak">
+ discussion</A>.</P>
+</DD>
+<DT><A name="X">X</A></DT>
+<DT><A name="X509">X.509</A></DT>
+<DD>A standard from the<A href="http://www.itu.int"> ITU (International
+ Telecommunication Union)</A>, for hierarchical directories with
+ authentication services, used in many<A href="#PKI"> PKI</A>
+ implementations.
+<P>Use of X.509 services, via the<A href="#LDAP"> LDAP protocol</A>, for
+ certification of keys is allowed but not required by the<A href="#IPSEC">
+ IPsec</A> RFCs. It is not yet implemented in<A href="web.html#FreeSWAN">
+ Linux FreeS/WAN</A>.</P>
+</DD>
+<DT>Xedia</DT>
+<DD>A vendor of router and Internet access products, now part of Lucent.
+ Their QVPN products interoperate with Linux FreeS/WAN; see our<A href="interop.html#Xedia">
+ interop document</A>.</DD>
+<DT><A name="Y">Y</A></DT>
+<DT><A name="Z">Z</A></DT>
+</DL>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="web.html">Previous</A>
+<A HREF="biblio.html">Next</A>
+</BODY>
+</HTML>
diff --git a/doc/impl.notes b/doc/impl.notes
new file mode 100644
index 000000000..6ea3678b6
--- /dev/null
+++ b/doc/impl.notes
@@ -0,0 +1,127 @@
+Introduction
+
+This document is some quick notes to sophisticated implementors, on topics
+which are a bit too arcane to be mentioned in the install instructions.
+Beware that it is not updated very often, and may be behind the times.
+This file is RCSID $Id: impl.notes,v 1.1 2004/03/15 20:35:21 as Exp $
+
+
+
+Where are things?
+
+If your kernel sources are not located in /usr/src/linux, or local manual
+pages are not in /usr/local/man/man[1-8], you've got a problem.  You may
+be able to get around it to some extent just by modifying the top-level
+Makefile, but we don't promise.  For a different manpage location, that
+will probably suffice; for a different kernel location, probably not. 
+We'd welcome reports of what needs to be fixed for this. 
+
+
+
+Cross-compiling
+
+At the moment, this distribution makes no attempt to support building
+the software on one machine for use on another.  That's hard, especially
+since the Linux kernel sources are not set up for it at all.
+
+
+
+One thing at a time
+
+(CAUTION:  This is somewhat outdated.  It's retained because it may be a
+useful guide for experts.  Consult the Makefile for current details.)
+
+If you want to do the build and install one step at a time, instead of
+using the prepackaged make commands like "make menugo", do the following
+instead.  (We do things in a slightly different order here, to avoid
+unnecessary directory changing.)
+
+To fit the kernel part of KLIPS into the kernel sources, do:
+
+	make insert
+
+(This makes a symbolic link /usr/src/linux/net/ipsec, pointing to the
+KLIPS source directory.  It patches some kernel files, where necessary, to
+know about KLIPS and/or to fix bugs.  It adds a default configuration to
+the kernel configuration file.  Finally, it makes the KLIPS communication
+file, /dev/ipsec, if it's not already there.)
+
+Build the libraries, Pluto, and various user-level utilities: 
+
+	make programs
+
+Install the Pluto daemon and user-level utilities, and set things up for
+boot-time startup:
+
+	make install
+
+Configure the kernel:
+
+	cd /usr/src/linux
+	make menuconfig          # (or xconfig, or whatever)
+
+See the configuration step of INSTALL for details of what to do within
+the configuration program.  Don't forget to save the results.
+
+Go through the usual kernel make process (still in /usr/src/linux):
+
+	make dep clean zImage
+
+Caution:  the Linux kernel Makefiles are not always careful about checking
+for errors.  We recommend capturing the output of this step and searching
+it for any occurrence of "error", "Error", etc.  The details of how to do
+so are unfortunately somewhat shell-dependent, although if you are using
+the standard shell (rather than csh, tcsh, etc.), this would do:
+
+	make dep clean zImage 2>&1 | tee junk
+	egrep -i error junk		# no output is good output
+
+(One glitch here is that the word "error" can sometimes occur legitimately
+in the make output.  For example, the kernel math emulation package has a
+source file "errors.c".  Some judgement is required to ignore such false
+alarms.)  The prepackaged make commands do all this for you.
+
+If your kernel is using loadable modules, you'll also need to do:
+
+	make modules
+
+Now you need to install the resulting kernel.  If you're not using the
+kernel's "make install" -- many people aren't -- then you need to do your
+usual install procedure.  You might want to read doc/kernel.notes, which
+recounts some of our experiences with RedHat 5.2 kernel installation in
+particular.
+
+If "make install" is good enough for you, then: 
+
+	make install
+
+(Same comments on error checking as in previous step.)  If your kernel is
+using loadable modules, you'll also need to do: 
+
+	make modules_install
+
+Finally, go back to INSTALL for the remaining steps.
+
+
+
+Klips as a module
+
+It is possible to run Klips as a kernel module, meaning that it does not
+have to be loaded until needed.  Formerly this was necessary, in fact,
+because Klips wouldn't run any other way.  Now it will, and we recommend
+static linking ("y", not "m", to the configuration question) for security.
+Klips is not terribly large (tens of KB, not hundreds) and should not
+cause size problems unless your kernel is already pushing the limits.
+
+However, Klips does still run as a module, if you want (although beware
+that we don't test this option very often).  "ipsec setup start" and
+"ipsec setup stop" load and unload it as appropriate, and you should not
+need to do anything about that yourself.
+
+
+
+Old Red Hats
+
+Our development is currently on a mix of Red Hat 6.2 and 7.1, with 6.2
+fading fast.  Our older Red Hats have been retired, and although FreeS/WAN
+should still work on them, we no longer make any attempt to ensure that. 
diff --git a/doc/index.html b/doc/index.html
new file mode 100644
index 000000000..427ed7ea7
--- /dev/null
+++ b/doc/index.html
@@ -0,0 +1,55 @@
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>FreeS/WAN index</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, encryption, cryptography, FreeS/WAN, FreeSWAN">
+  <!--
+
+  Written by Claudia Schmeing for the Linux FreeS/WAN project
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: index.html,v 1.1 2004/03/15 20:35:21 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:21 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+
+<body>
+<h1>FreeS/WAN documentation</h1>
+
+<ul>
+  <li><a href="intro.html">Introduction</a></li>
+  <li><a href="upgrading.html">Upgrading to 2.x</a></li>
+</ul>
+
+<ul> 
+  <li><a href="quickstart.html">Quickstart guide to Opportunistic Encryption</a></li>
+  <li><a href="install.html">Installing</a></li>
+  <li><a href="config.html">Configuring</a></li>
+  <li><a href="policygroups.html">Policy Groups</a> 
+                   </li>
+  <li><a href="interop.html">Interoperating</a> 
+<FONT COLOR="#FF0000">New and improved!</FONT></li>
+  <li><a href="faq.html">FAQ</a></li>
+  <li><a href="trouble.html">Troubleshooting and problem reporting</a></li>
+</ul>
+
+<ul>
+  <li><a href="toc.html">Full table of contents, with much more</a></li>
+  <li><a href="HowTo.html">All our docs as one big file</a></li>
+</ul>  
+
+<p>For technical support and other questions, use our <a
+href="mail.html">mailing lists</a>.</p>
+
+<pre>        This index last changed:    $Date: 2004/03/15 20:35:21 $</pre>
+
+</body>
+</html>
diff --git a/doc/install.html b/doc/install.html
new file mode 100644
index 000000000..6cd55535e
--- /dev/null
+++ b/doc/install.html
@@ -0,0 +1,286 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
+H5 { font-family: sans-serif }
+H6 { font-family: sans-serif }
+SUB { font-size: smaller }
+SUP { font-size: smaller }
+PRE { font-family: monospace }
+--></STYLE>
+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="adv_config.html">Previous</A>
+<A HREF="config.html">Next</A>
+<HR>
+<H1><A name="install">Installing FreeS/WAN</A></H1>
+<P>This document will teach you how to install Linux FreeS/WAN. If your
+ distribution comes with Linux FreeS/WAN, we offer tips to get you
+ started.</P>
+<H2><A NAME="15_1">Requirements</A></H2>
+<P>To install FreeS/WAN you must:</P>
+<UL>
+<LI>be running Linux with the 2.4 or 2.2 kernel series. See this<A HREF="http://www.freeswan.ca/download.php#contact">
+ kernel compatibility table</A>.
+<BR>We also have experimental support for 2.6 kernels. Here are two
+ basic approaches:
+<UL>
+<LI> install FreeS/WAN, including its<A HREF="ipsec.html#parts"> KLIPS</A>
+ kernel code. This will remove the native IPsec stack and replace it
+ with KLIPS.</LI>
+<LI> install the FreeS/WAN<A HREF="ipsec.html#parts"> userland tools</A>
+ (keying daemon and supporting scripts) for use with<A HREF="http://lartc.org/howto/lartc.ipsec.html">
+ 2.6 kernel native IPsec</A>,</LI>
+</UL>
+ See also these<A HREF="2.6.known-issues"> known issues with 2.6</A>.</LI>
+<LI>have root access to your Linux box</LI>
+<LI>choose the version of FreeS/WAN you wish to install based on<A HREF="http://www.freeswan.org/mail.html">
+ mailing list reports</A>
+<!-- or 
+our updates page (coming soon)-->
+</LI>
+</UL>
+<H2><A NAME="15_2">Choose your install method</A></H2>
+<P>There are three basic ways to get FreeS/WAN onto your system:</P>
+<UL>
+<LI>activating and testing a FreeS/WAN that<A HREF="#distroinstall">
+ shipped with your Linux distribution</A></LI>
+<LI><A HREF="#rpminstall">RPM install</A></LI>
+<LI><A HREF="#srcinstall">Install from source</A></LI>
+</UL>
+<A NAME="distroinstall"></A>
+<H2><A NAME="15_3">FreeS/WAN ships with some Linuxes</A></H2>
+<P>FreeS/WAN comes with<A HREF="intro.html#distwith"> these
+ distributions</A>.</P>
+<P>If you're running one of these, include FreeS/WAN in the choices you
+ make during installation, or add it later using the distribution's
+ tools.</P>
+<H3><A NAME="15_3_1">FreeS/WAN may be altered...</A></H3>
+<P>Your distribution may have integrated extra features, such as Andreas
+ Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup
+ script locations or directory names.</P>
+<H3><A NAME="15_3_2">You might need to create an authentication keypair</A>
+</H3>
+<P>If your FreeS/WAN came with your distribution, you may wish to
+ generate a fresh RSA key pair. FreeS/WAN will use these keys for
+ authentication.</P>
+<P> To do this, become root, and type:</P>
+<PRE>    ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
+    chmod 600 /etc/ipsec.secrets</PRE>
+<P>where you replace xy.example.com with your machine's fully-qualified
+ domain name. Generate some randomness, for example by wiggling your
+ mouse, to speed the process.</P>
+<P>The resulting ipsec.secrets looks like:</P>
+<PRE>: RSA   {
+        # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
+        # for signatures only, UNSAFE FOR ENCRYPTION
+        #pubkey=0sAQOFppfeE3cC7wqJi...
+        Modulus: 0x85a697de137702ef0...
+        # everything after this point is secret
+        PrivateExponent: 0x16466ea5033e807...
+        Prime1: 0xdfb5003c8947b7cc88759065...
+        Prime2: 0x98f199b9149fde11ec956c814...
+        Exponent1: 0x9523557db0da7a885af90aee...
+        Exponent2: 0x65f6667b63153eb69db8f300dbb...
+        Coefficient: 0x90ad00415d3ca17bebff123413fc518...
+        }
+# do not change the indenting of that &quot;}&quot;</PRE>
+<P>In the actual file, the strings are much longer.</P>
+<H3><A NAME="15_3_3">Start and test FreeS/WAN</A></H3>
+<P>You can now<A HREF="install.html#starttest"> start FreeS/WAN and test
+ whether it's been successfully installed.</A>.</P>
+<A NAME="rpminstall"></A>
+<H2><A NAME="15_4">RPM install</A></H2>
+<P>These instructions are for a recent Red Hat with a stock Red Hat
+ kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If
+ you're running either, install using your distribution's tools.</P>
+<H3><A NAME="15_4_1">Download RPMs</A></H3>
+<P>Decide which functionality you need:</P>
+<UL>
+<LI>standard FreeS/WAN RPMs. Use these shortcuts:
+<BR>
+<UL>
+<LI>(for 2.6 kernels: userland only)
+<BR> ncftpget
+ ftp://ftp.xs4all.nl/pub/crypto/freeswan/binaries/RedHat-RPMs/\*userland*
+</LI>
+<LI>(for 2.4 kernels)
+<BR> ncftpget
+ ftp://ftp.xs4all.nl/pub/crypto/freeswan/binaries/RedHat-RPMs/`uname -r
+ | tr -d 'a-wy-z'`/\*</LI>
+<LI> or view all the offerings at our<A href="ftp://ftp.xs4all.nl/pub/crypto/freeswan/binaries/RedHat-RPMs">
+ FTP site</A>.</LI>
+</UL>
+</LI>
+<LI>unofficial<A href="http://www.freeswan.ca/download.php"> Super
+ FreeS/WAN</A> RPMs, which include Andreas Steffen's X.509 patch and
+ more. Super FreeS/WAN RPMs do not currently include<A HREF="glossary.html#NAT.gloss">
+ Network Address Translation</A> (NAT) traversal, but Super FreeS/WAN
+ source does.</LI>
+</UL>
+<A NAME="2.6.rpm"></A>
+<P>For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:</P>
+<PRE>    freeswan-userland-2.04.9-0.i386.rpm</PRE>
+<P>Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please
+ see<A HREf="2.6.known-issues"> 2.6.known-issues</A>, and the latest<A HREF="http://www.freeswan.org/mail.html">
+ mailing list reports</A>.</P>
+<P>Change to your new FreeS/WAN directory, and make and install the</P>
+<P>For 2.4 kernels, get both kernel and userland RPMs. Check your kernel
+ version with</P>
+<PRE>    uname -r</PRE>
+<P>Get a kernel module which matches that version. For example:</P>
+<PRE>    freeswan-module-2.04_2.4.20_20.9-0.i386.rpm</PRE>
+<P>Note: These modules<B> will only work on the Red Hat kernel they were
+ built for</B>, since they are very sensitive to small changes in the
+ kernel.</P>
+<P>Get FreeS/WAN utilities to match. For example:</P>
+<PRE>    freeswan-userland-2.04_2.4.20_20.9-0.i386.rpm</PRE>
+<H3><A NAME="15_4_2">For freeswan.org RPMs: check signatures</A></H3>
+<P>While you're at our ftp site, grab the RPM signing key</P>
+<PRE>    freeswan-rpmsign.asc</PRE>
+<P>If you're running RedHat 8.x or later, import this key into the RPM
+ database:</P>
+<PRE>    rpm --import freeswan-rpmsign.asc</PRE>
+<P>For RedHat 7.x systems, you'll need to add it to your<A HREF="glossary.html#PGP">
+ PGP</A> keyring:</P>
+<PRE>    pgp -ka freeswan-rpmsign.asc</PRE>
+<P>Check the digital signatures on both RPMs using:</P>
+<PRE>    rpm --checksig freeswan*.rpm </PRE>
+<P>You should see that these signatures are good:</P>
+<PRE>    freeswan-module-2.04_2.4.20_20.9-0.i386.rpm: pgp md5 OK
+    freeswan-userland-2.04_2.4.20_20.9-0.i386.rpm: pgp md5 OK</PRE>
+<H3><A NAME="15_4_3">Install the RPMs</A></H3>
+<P>Become root:</P>
+<PRE>    su</PRE>
+<P>For a first time install, use:</P>
+<PRE>    rpm -ivh freeswan*.rpm</PRE>
+<P>To upgrade existing RPMs (and keep all .conf files in place), use:</P>
+<PRE>    rpm -Uvh freeswan*.rpm</PRE>
+<P>If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter
+ problems, see<A HREF="upgrading.html#upgrading.rpms"> this note</A>.</P>
+<H3><A NAME="15_4_4">Start and Test FreeS/WAN</A></H3>
+<P>Now,<A HREF="install.html#starttest"> start FreeS/WAN and test your
+ install</A>.</P>
+<A NAME="srcinstall"></A>
+<H2><A NAME="15_5">Install from Source</A></H2>
+
+<!-- Most of this section, along with "Start and Test", can replace 
+INSTALL. -->
+<H3><A NAME="15_5_1">Decide what functionality you need</A></H3>
+<P>Your choices are:</P>
+<UL>
+<LI><A HREF="ftp://ftp.xs4all.nl/pub/crypto/freeswan">standard FreeS/WAN</A>
+,</LI>
+<LI>standard FreeS/WAN plus any of these<A HREF="web.html#patch">
+ user-supported patches</A>, or</LI>
+<LI><A HREF="http://www.freeswan.ca/download">Super FreeS/WAN</A>, an
+ unofficial FreeS/WAN pre-patched with many of the above. Provides
+ additional algorithms, X.509, SA deletion, dead peer detection, and<A HREF="glossary.html#NAT.gloss">
+ Network Address Translation</A> (NAT) traversal.</LI>
+</UL>
+<H3><A NAME="15_5_2">Download FreeS/WAN</A></H3>
+<P>Download the source tarball you've chosen, along with any patches.</P>
+<H3><A NAME="15_5_3">For freeswan.org source: check its signature</A></H3>
+<P>While you're at our ftp site, get our source signing key</P>
+<PRE>    freeswan-sigkey.asc</PRE>
+<P>Add it to your PGP keyring:</P>
+<PRE>    pgp -ka freeswan-sigkey.asc</PRE>
+<P>Check the signature using:</P>
+<PRE>    pgp freeswan-2.04.tar.gz.sig freeswan-2.04.tar.gz</PRE>
+<P>You should see something like:</P>
+<PRE>    Good signature from user &quot;Linux FreeS/WAN Software Team (build@freeswan.org)&quot;.
+    Signature made 2002/06/26 21:04 GMT using 2047-bit key, key ID 46EAFCE1</PRE>
+
+<!-- Note to self: build@freeswan.org has angled brackets in the original.
+     Changed because it conflicts with HTML tags. -->
+<H3><A NAME="15_5_4">Untar, unzip</A></H3>
+<P>As root, unpack your FreeS/WAN source into<VAR> /usr/src</VAR>.</P>
+<PRE>    su
+    mv freeswan-2.04.tar.gz /usr/src
+    cd /usr/src
+    tar -xzf freeswan-2.04.tar.gz
+</PRE>
+<H3><A NAME="15_5_5">Patch if desired</A></H3>
+<P>Now's the time to add any patches. The contributor may have special
+ instructions, or you may simply use the patch command.</P>
+<H3><A NAME="15_5_6">... and Make</A></H3>
+<P>Choose one of the methods below.</P>
+<H4>Userland-only Install for 2.6 kernels</H4>
+<A NAME="2.6.src"></A>
+<P>Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please
+ see<A HREf="2.6.known-issues"> 2.6.known-issues</A>, and the latest<A HREF="http://www.freeswan.org/mail.html">
+ mailing list reports</A>.</P>
+<P>Change to your new FreeS/WAN directory, and make and install the
+ FreeS/WAN userland tools.</P>
+<PRE>    cd /usr/src/freeswan-2.04
+    make programs
+    make install</PRE>
+<P>Now,<A HREF="install.html#starttest"> start FreeS/WAN and test your
+ install</A>.</P>
+<H4>KLIPS install for 2.2, 2.4, or 2.6 kernels</H4>
+<A NAME="modinstall"></A>
+<P>To make a modular version of KLIPS, along with other FreeS/WAN
+ programs you'll need, use the command sequence below. This will change
+ to your new FreeS/WAN directory, make the FreeS/WAN module (and other
+ stuff), and install it all.</P>
+<PRE>    cd /usr/src/freeswan-2.04
+    make oldmod
+    make minstall</PRE>
+<P><A HREF="install.html#starttest">Start FreeS/WAN and test your
+ install</A>.</P>
+<P>To link KLIPS statically into your kernel (using your old kernel
+ settings), and install other FreeS/WAN components, do:</P>
+<PRE>    cd /usr/src/freeswan-2.04
+    make oldmod
+    make minstall</PRE>
+<P>Reboot your system and<A HREF="install.html#testonly"> test your
+ install</A>.</P>
+<P>For other ways to compile KLIPS, see our Makefile.</P>
+<A name="starttest"></A>
+<H2><A NAME="15_6">Start FreeS/WAN and test your install</A></H2>
+<P>Bring FreeS/WAN up with:</P>
+<PRE>    service ipsec start</PRE>
+<P>This is not necessary if you've rebooted.</P>
+<A name="testonly"></A>
+<H2><A NAME="15_7">Test your install</A></H2>
+<P>To check that you have a successful install, run:</P>
+<PRE>    ipsec verify</PRE>
+<P>You should see at least:</P>
+<PRE>
+    Checking your system to see if IPsec got installed and started correctly
+    Version check and ipsec on-path                             [OK]
+    Checking for KLIPS support in kernel                        [OK]
+    Checking for RSA private key (/etc/ipsec.secrets)           [OK]
+    Checking that pluto is running                              [OK]
+</PRE>
+<P>If any of these first four checks fails, see our<A href="trouble.html#install.check">
+ troubleshooting guide</A>.</P>
+<H2><A NAME="15_8">Making FreeS/WAN play well with others</A></H2>
+<P>There are at least a couple of things on your system that might
+ interfere with FreeS/WAN, and now's a good time to check these:</P>
+<UL>
+<LI>Firewalling. You need to allow UDP 500 through your firewall, plus
+ ESP (protocol 50) and AH (protocol 51). For more information, see our
+ updated firewalls document (coming soon).</LI>
+<LI>Network address translation. Do not NAT the packets you will be
+ tunneling.</LI>
+</UL>
+<H2><A NAME="15_9">Configure for your needs</A></H2>
+<P>You'll need to configure FreeS/WAN for your local site. Have a look
+ at our<A HREF="quickstart.html"> opportunism quickstart guide</A> to
+ see if that easy method is right for your needs. Or, see how to<A HREF="config.html">
+ configure a network-to-network or Road Warrior style VPN</A>.</P>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="adv_config.html">Previous</A>
+<A HREF="config.html">Next</A>
+</BODY>
+</HTML>
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
+H5 { font-family: sans-serif }
+H6 { font-family: sans-serif }
+SUB { font-size: smaller }
+SUP { font-size: smaller }
+PRE { font-family: monospace }
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+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="compat.html">Previous</A>
+<A HREF="performance.html">Next</A>
+<HR>
+<A NAME="interop"></A>
+<H1><A NAME="10">Interoperating with FreeS/WAN</A></H1>
+<P>The FreeS/WAN project needs you! We rely on the user community to
+ keep up to date. Mail users@lists.freeswan.org with your interop
+ success stories.</P>
+<P><STRONG>Please note</STRONG>: Most of our interop examples feature
+ Linux FreeS/WAN 1.x config files. You can convert them to 2.x files
+ fairly easily with the patch in our<A HREF="upgrading.html#ipsec.conf_v2">
+ Upgrading Guide</A>.</P>
+<H2><A NAME="10_1">Interop at a Glance</A></H2>
+<TABLE BORDER="1">
+<TR><TD>&nbsp;</TD><TD colspan="5">FreeS/WAN VPN</TD><TD>Road Warrior</TD><TD>
+OE</TD></TR>
+<TR><TD>&nbsp;</TD><TD>PSK</TD><TD>RSA Secret</TD><TD>X.509
+<BR><SMALL><A HREF="#interoprules">(requires patch)</A></SMALL></TD><TD>
+NAT-Traversal
+<BR><SMALL><A HREF="#interoprules">(requires patch)</A></SMALL></TD><TD>
+Manual
+<BR>Keying</TD><TD>&nbsp;</TD><TD>&nbsp;</TD></TR>
+<TR><TD colspan="8">More Compatible</TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="web.html#freeswan">FreeS/WAN</A><A NAME="freeswan.top">
+ &nbsp;</A></TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD><FONT color="#00cc00">Yes</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#isakmpd">isakmpd (OpenBSD)</A><A NAME="isakmpd.top"> &nbsp;</A>
+</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>
+<FONT color="#cc0000">No&nbsp;&nbsp;&nbsp;&nbsp;</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#kame">Kame (FreeBSD,
+<BR> NetBSD, MacOSX)
+<BR> <SMALL>aka racoon</SMALL></A><A NAME="kame.top"> &nbsp;</A></TD><TD><FONT
+color="#00cc00">Yes</FONT></TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>
+<FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#mcafee">McAfee VPN
+<BR><SMALL>was PGPNet</SMALL></A><A NAME="mcafee.top"> &nbsp;</A></TD><TD><FONT
+color="#00cc00">Yes</FONT></TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>
+<FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#microsoft">Microsoft
+<BR> Windows 2000/XP</A><A NAME="microsoft.top"> &nbsp;</A></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD><FONT color="#cc0000">
+No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="glossary.html#ssh">SSH Sentinel</A><A NAME="ssh.top"> &nbsp;</A>
+</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD><FONT color="#cccc00">Maybe</FONT></TD><TD>&nbsp;</TD><TD><FONT
+color="#00cc00">Yes</FONT></TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#safenet">Safenet SoftPK
+<BR>/SoftRemote</A><A NAME="safenet.top"> &nbsp;</A></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD><FONT color="#cc0000">
+No</FONT></TD></TR>
+<TR><TD colspan="8">Other</TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#6wind">6Wind</A><A NAME="6wind.top"> &nbsp;</A></TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+<FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#alcatel">Alcatel Timestep</A><A NAME="alcatel.top"> &nbsp;</A>
+</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#apple">Apple Macintosh
+<BR>System 10+</A><A NAME="apple.top"> &nbsp;</A></TD><TD><FONT color="#cccc00">
+Maybe</FONT></TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD><FONT color="#cccc00">
+Maybe</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#cccc00">Maybe</FONT></TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#ashleylaurent">AshleyLaurent
+<BR> VPCom</A><A NAME="ashleylaurent.top"> &nbsp;</A></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT
+color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#borderware">Borderware</A><A NAME="borderware.top"> &nbsp;</A>
+</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD><TD><FONT color="#cc0000">
+No</FONT></TD></TR>
+
+<!--
+http://www.cequrux.com/vpn-guides.php3
+"coming soon" guide to connect with FreeS/WAN.
+-->
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#checkpoint">Check Point FW-1/VPN-1</A><A NAME="checkpoint.top">
+ &nbsp;</A></TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>
+<FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#cisco">Cisco with 3DES</A><A NAME="cisco.top"> &nbsp;</A></TD><TD>
+<FONT color="#00cc00">Yes</FONT></TD><TD><FONT color="#cccc00">Maybe</FONT>
+</TD><TD>&nbsp;</TD><TD><FONT color="#cccc00">Maybe</FONT></TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#equinux">Equinux VPN Tracker
+<BR> (for Mac OS X)</A><A NAME="equinux.top"> &nbsp;</A></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#cccc00">Maybe</FONT></TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#fsecure">F-Secure</A><A NAME="fsecure.top"> &nbsp;</A></TD><TD>
+<FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#cccc00">
+Maybe</FONT></TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#gauntlet">Gauntlet GVPN</A><A NAME="gauntlet.top"> &nbsp;</A>
+</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#cc0000">
+No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#aix">IBM AIX</A><A NAME="aix.top"> &nbsp;</A></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#cccc00">Maybe</FONT></TD><TD>
+&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#as400">IBM AS/400</A><A NAME="as400"> &nbsp;</A></TD><TD><FONT
+color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#intel">Intel Shiva
+<BR>LANRover/Net Structure</A><A NAME="intel.top"> &nbsp;</A></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT
+color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#lancom">LanCom (formerly ELSA)</A><A NAME="lancom.top">
+ &nbsp;</A></TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#linksys">Linksys</A><A NAME="linksys.top"> &nbsp;</A></TD><TD>
+<FONT color="#cccc00">Maybe</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#cc0000">
+No</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>
+<FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#lucent">Lucent</A><A NAME="lucent.top"> &nbsp;</A></TD><TD><FONT
+color="#cccc00">Partial</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#netasq">Netasq</A><A NAME="netasq.top"> &nbsp;</A></TD><TD>
+&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#netcelo">netcelo</A><A NAME="netcelo.top"> &nbsp;</A></TD><TD>
+&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#netgear">Netgear fvs318</A><A NAME="netgear.top"> &nbsp;</A>
+</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#netscreen">Netscreen 100
+<BR>or 5xp</A><A NAME="netscreen.top"> &nbsp;</A></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#cccc00">
+Maybe</FONT></TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#nortel">Nortel Contivity</A><A NAME="nortel.top"> &nbsp;</A>
+</TD><TD><FONT color="#cccc00">Partial</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD><FONT color="#cccc00">Maybe</FONT></TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#radguard">RadGuard</A><A NAME="radguard.top"> &nbsp;</A></TD><TD>
+<FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#raptor">Raptor</A><A NAME="raptor"> &nbsp;</A></TD><TD><FONT
+color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#redcreek">Redcreek Ravlin</A><A NAME="redcreek.top"> &nbsp;</A>
+</TD><TD><FONT color="#00cc00">Yes</FONT><FONT color="#cccc00">/Partial</FONT>
+</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#cc0000">
+No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#sonicwall">SonicWall</A><A NAME="sonicwall.top"> &nbsp;</A></TD><TD>
+<FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT
+color="#cccc00">Maybe</FONT></TD><TD><FONT color="#cc0000">No</FONT></TD><TD>
+<FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#sun">Sun Solaris</A><A NAME="sun.top"> &nbsp;</A></TD><TD><FONT
+color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT>
+</TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT
+color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#symantec">Symantec</A><A NAME="symantec.top"> &nbsp;</A></TD><TD>
+<FONT color="#00cc00">Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>
+&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#watchguard">Watchguard
+<BR> Firebox</A><A NAME="watchguard.top"> &nbsp;</A></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD><FONT color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#xedia">Xedia Access Point
+<BR>/QVPN</A><A NAME="xedia.top"> &nbsp;</A></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT
+color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR><TD><A HREF="#zyxel">Zyxel Zywall
+<BR>/Prestige</A><A NAME="zyxel.top"> &nbsp;</A></TD><TD><FONT color="#00cc00">
+Yes</FONT></TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD>&nbsp;</TD><TD><FONT
+color="#cc0000">No</FONT></TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE
+
+
+<TR>
+<TD><A HREF="#sample">sample</A></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+-->
+<TR><TD>&nbsp;</TD><TD>PSK</TD><TD>RSA Secret</TD><TD>X.509
+<BR><SMALL><A HREF="#interoprules">(requires patch)</A></SMALL></TD><TD>
+NAT-Traversal
+<BR><SMALL><A HREF="#interoprules">(requires patch)</A></SMALL></TD><TD>
+Manual
+<BR>Keying</TD><TD>&nbsp;</TD><TD>&nbsp;</TD></TR>
+<TR><TD>&nbsp;</TD><TD colspan="5">FreeS/WAN VPN</TD><TD>Road Warrior</TD><TD>
+OE</TD></TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+</TABLE>
+<H3><A NAME="10_1_1">Key</A></H3>
+<TABLE BORDER="1">
+<TR><TD><FONT color="#00cc00">Yes</FONT></TD><TD>People report that this
+ works for them.</TD></TR>
+<TR><TD>[Blank]</TD><TD>We don't know.</TD></TR>
+<TR><TD><FONT color="#cc0000">No</FONT></TD><TD>We have reason to
+ believe it was, at some point, not possible to get this to work.</TD></TR>
+<TR><TD><FONT color="#cccc00">Partial</FONT></TD><TD>Partial success.
+ For example, a connection can be created from one end only.</TD></TR>
+<TR><TD><FONT color="#00cc00">Yes</FONT><FONT color="#cccc00">/Partial</FONT>
+</TD><TD>Mixed reports.</TD></TR>
+<TR><TD><FONT color="#cccc00">Maybe</FONT></TD><TD>We think the answer
+ is &quot;yes&quot;, but need confirmation.</TD></TR>
+</TABLE>
+<A NAME="interoprules"></A>
+<H2><A NAME="10_2">Basic Interop Rules</A></H2>
+<P>Vanilla FreeS/WAN implements<A HREF="compat.html#compat"> these parts</A>
+ of the IPSec specifications. You can add more with<A HREF="http://www.freeswan.ca">
+ Super FreeS/WAN</A>, but what we offer may be enough for many users.</P>
+<UL>
+<LI> To use X.509 certificates with FreeS/WAN, you will need the<A HREF="http://www.strongsec.org/freeswan">
+ X.509 patch</A> or<A HREF="http://www.freeswan.ca"> Super FreeS/WAN</A>
+, which includes that patch.</LI>
+<LI> To use<A HREF="glossary.html#NAT.gloss"> Network Address
+ Translation</A> (NAT) traversal with FreeS/WAN, you will need Arkoon
+ Network Security's<A HREF="http://open-source.arkoon.net"> NAT
+ traversal patch</A> or<A HREF="http://www.freeswan.ca"> Super FreeS/WAN</A>
+, which includes it.</LI>
+</UL>
+<P>We offer a set of proposals which is not user-adjustable, but covers
+ all combinations that we can offer. FreeS/WAN always proposes triple
+ DES encryption and Perfect Forward Secrecy (PFS). In addition, we
+ propose Diffie Hellman groups 5 and 2 (in that order), and MD5 and
+ SHA-1 hashes. We accept the same proposals, in the same order of
+ preference.</P>
+<P>Other interop notes:</P>
+<UL>
+<LI> A<A HREF="http://lists.freeswan.org/archives/users/2003-September/msg00462.html">
+ SHA-1 bug in FreeS/WAN 2.00, 2.01 and 2.02</A> may affect some interop
+ scenarios. It does not affect 1.x versions, and is fixed in 2.03 and
+ later.</LI>
+<LI> Some other implementations will close a connection with FreeS/WAN
+ after some time. This may be a problem with rekey lifetimes. Please see<A
+HREF="http://lists.freeswan.org/archives/users/2003-October/msg00293.html">
+ this tip</A> and<A HREF="http://lists.freeswan.org/pipermail/users/2001-December/005758.html">
+ this workaround</A>.</LI>
+</UL>
+<H2><A NAME="10_3">Longer Stories</A></H2>
+<H3><A NAME="10_3_1">For<EM> More Compatible</EM> Implementations</A></H3>
+<H4><A NAME="freeswan">FreeS/WAN</A></H4>
+<P> See our documentation at<A HREF="http://www.freeswan.org">
+ freeswan.org</A> and the Super FreeS/WAN docs at<A HREF="http://www.freeswan.ca">
+ freeswan.ca</A>. Some user-written HOWTOs for FreeS/WAN-FreeS/WAN
+ connections are listed in<A HREF="intro.html#howto"> our Introduction</A>
+.</P>
+<P>See also:</P>
+<UL>
+<LI><A HREF="http://lugbe.ch/action/reports/ipsec_htbe.phtml"> A German
+ FreeS/WAN-FreeS/WAN page by Markus Wernig (X.509)</A></LI>
+</UL>
+<P><A HREF="#freeswan.top">Back to chart</A></P>
+<H4><A NAME="isakmpd">isakmpd (OpenBSD)</A></H4>
+<P><A HREF="http://www.openbsd.org/faq/faq13.html">OpenBSD FAQ: Using
+ IPsec</A>
+<BR><A HREF="http://www.rommel.stw.uni-erlangen.de/~hshoexer/ipsec-howto/HOWTO.html">
+ Hans-Joerg Hoexer's interop Linux-OpenBSD (PSK)</A>
+<BR><A HREF="http://www.segfault.net/ipsec/"> Skyper's configuration
+ (PSK)</A>
+<BR><A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+ French page with configs (X.509)</A></P>
+<P><A HREF="#isakmpd.top">Back to chart</A></P>
+<H4><A NAME="kame">Kame</A></H4>
+<UL>
+<LI>For FreeBSD and NetBSD. Ships with Mac OS X; see also our<A HREF="#apple">
+ Mac</A> section.</LI>
+<LI>Also known as<EM> racoon</EM>, its keying daemon.</LI>
+</UL>
+<P><A HREF="http://www.kame.net">Kame homepage, with FAQ</A>
+<BR><A HREF="http://www.netbsd.org/Documentation/network/ipsec">
+ NetBSD's IPSec FAQ</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/12/msg00560.html">
+ Ghislaine's post explaining some interop peculiarities</A></P>
+<P><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/09/msg00511.html">
+ Itojun's Kame-FreeS/WAN interop tips (PSK)</A>
+<BR><A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2000"> Ghislaine
+ Labouret's French page with links to matching FreeS/WAN and Kame
+ configs (RSA)</A>
+<BR><A HREF="http://lugbe.ch/lostfound/contrib/freebsd_router/"> Markus
+ Wernig's HOWTO (X.509, BSD gateway)</A>
+<BR><A HREF="http://web.morgul.net/~frodo/docs/kame+freeswan_interop.html">
+ Frodo's Kame-FreeS/WAN interop (X.509)</A>
+<BR><A HREF="http://www.wavesec.org/kame.phtml"> Kame as a WAVEsec
+ client.</A></P>
+<P><A HREF="#kame.top">Back to chart</A></P>
+<H4><A NAME="mcafee">PGPNet/McAfee</A></H4>
+<P></P>
+<UL>
+<LI>Now called McAfee VPN Client.</LI>
+<LI>PGPNet also came in a freeware version which did not support subnets</LI>
+<LI>To support dhcp-over-ipsec, you need the X.509 patch, which is
+ included in<A HREF="http://www.freeswan.ca"> Super FreeS/WAN</A>.</LI>
+</UL>
+<P><A HREF="http://www.freeswan.ca/docs/WindowsInterop"> Tim Carr's
+ Windows Interop Guide (X.509)</A>
+<BR><A HREF="http://www.rommel.stw.uni-erlangen.de/~hshoexer/ipsec-howto/HOWTO.html#Interop2">
+ Hans-Joerg Hoexer's Guide for Linux-PGPNet (PSK)</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/04/msg00339.html">
+ Kai Martius' instructions using RSA Key-Extractor Tool (RSA)</A>
+<BR> &nbsp;&nbsp;&nbsp;&nbsp;<A HREF="http://www.zengl.net/freeswan/english.html">Christian
+ Zeng's page (RSA)</A> based on Kai's work. English or German.
+<BR><A HREF="http://tirnanog.ls.fi.upm.es/CriptoLab/Biblioteca/InfTech/InfTech_CriptoLab.htm">
+ Oscar Delgado's PDF (X.509, no configs)</A>
+<BR><A HREF="http://www-ec.njit.edu/~rxt1077/Howto.txt"> Ryan's HOWTO
+ for FreeS/WAN-PGPNet (X.509)</A>. Through a Linksys Router with IPsec
+ Passthru enabled.
+<BR><A HREF="http://jixen.tripod.com/#RW-PGP-to-Fwan"> Jean-Francois
+ Nadeau's Practical Configuration (Road Warrior with PSK)</A>
+<BR><A HREF="http://www.evolvedatacom.nl/freeswan.html#toc"> Wouter
+ Prins' HOWTO (Road Warrior with X.509)</A>
+<BR></P>
+<P><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/01/msg00271.html">
+ Rekeying problem with FreeS/WAN and older PGPNets</A>
+<BR></P>
+<P><A HREF="http://www.strongsec.com/freeswan/dhcprelay/index.htm"> DHCP
+ over IPSEC HOWTO for FreeS/WAN (requires X.509 and dhcprelay patches)</A>
+</P>
+<P><A HREF="#mcafee.top">Back to chart</A></P>
+<H4><A NAME="microsoft">Microsoft Windows 2000/XP</A></H4>
+<UL>
+<LI>IPsec comes with Win2k, and with XP Support Tools. May require<A HREF="http://www.microsoft.com/windows2000/downloads/recommended/encryption/default.asp">
+ High Encryption Pack</A>. WinXP users have also reported better results
+ with Service Pack 1.</LI>
+<LI>The Road Warrior setup works either way round. Windows (XP or 2K)
+ IPsec can connect as a Road Warrior to FreeS/WAN. However, FreeS/WAN
+ can also successfully connect as a Road Warrior to Windows IPsec (see
+ Nate Carlson's configs below).</LI>
+<LI>FreeS/WAN version 1.92 or later is required to avoid an
+ interoperation problem with Windows native IPsec. Earlier FreeS/WAN
+ versions did not process the Commit Bit as Windows native IPsec
+ expected.</LI>
+</UL>
+<P><A HREF="http://www.freeswan.ca/docs/WindowsInterop"> Tim Carr's
+ Windows Interop Guide (X.509)</A>
+<BR><A HREF="http://ipsec.math.ucla.edu/services/ipsec.html"> James
+ Carter's instructions (X.509, NAT-T)</A>
+<BR><A HREF="http://jixen.tripod.com/#Win2000-Fwan"> Jean-Francois
+ Nadeau's Net-net Configuration (PSK)</A>
+<BR><A HREF="http://security.nta.no/freeswan-w2k.html"> Telenor's
+ Node-node Config (Transport-mode PSK)</A>
+<BR><A HREF="http://vpn.ebootis.de"> Marcus Mueller's HOWTO using his
+ VPN config tool (X.509).</A> Tool also works with PSK.
+<BR><A HREF="http://www.natecarlson.com/include/showpage.php?cat=linux&page=ipsec-x509">
+ Nate Carlson's HOWTO using same tool (Road Warrior with X.509)</A>.
+ Unusually, FreeS/WAN is the Road Warrior here.
+<BR><A HREF="http://tirnanog.ls.fi.upm.es/CriptoLab/Biblioteca/InfTech/InfTech_CriptoLab.htm">
+ Oscar Delgado's PDF (X.509, no configs)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2003-July/022425.html">
+ Tim Scannell's Windows XP Additional Checklist (X.509)</A>
+<BR></P>
+
+<!-- Note to self: Include L2TP references? -->
+<P><A HREF="http://www.microsoft.com/windows2000/en/server/help/default.asp?url=/windows2000/en/server/help/sag_TCPIP_ovr_secfeatures.htm">
+ Microsoft's page on Win2k TCP/IP security features</A>
+<BR><A HREF="http://support.microsoft.com/support/kb/articles/Q257/2/25.ASP">
+ Microsoft's Win2k IPsec debugging tips</A>
+<BR>
+<!-- Alt-URL http://support.microsoft.com/default.aspx?scid=kb;EN-US;q257225
+Perhaps newer? -->
+<A HREF="http://www.wired.com/news/technology/0,1282,36336,00.html">
+ MS VPN may fall back to 1DES</A></P>
+<P><A HREF="#microsoft.top">Back to chart</A></P>
+<H4><A NAME="ssh">SSH Sentinel</A></H4>
+<UL>
+<LI>Popular and well tested.</LI>
+<LI>Also rebranded in<A HREF="http://www.zyxel.com"> Zyxel Zywall</A>.
+ Our Zyxel interop notes are<A HREF="#zyxel"> here</A>.</LI>
+<LI> SSH supports IPsec-over-UDP NAT traversal.</LI>
+<LI>There is this<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/12/msg00370.html">
+ potential problem</A> if you're not using the Legacy Proposal option.</LI>
+</UL>
+<P><A HREF="http://www.ssh.com/support/sentinel/documents.cfm"> SSH's
+ Sentinel-FreeSWAN interop PDF (X.509)</A>
+<BR><A HREF="http://www.nadmm.com/show.php?story=articles/vpn.inc">
+ Nadeem Hassan's SUSE-to-Sentinel article (Road warrior with X.509)</A>
+<BR><A HREF="http://www.zerozone.it/documents/Linux/HowTo/VPN-IPsec-Freeswan-HOWTO.html">
+ O-Zone's Italian HOWTO (Road Warrior, X.509, DHCP)</A>
+<BR></P>
+<P><A HREF="#ssh.top">Back to chart</A></P>
+<H4><A NAME="safenet">Safenet SoftPK/SoftRemote</A></H4>
+<UL>
+<LI>People recommend SafeNet as a low cost Windows client.</LI>
+<LI>SoftRemote seems to be the newer name for SoftPK.</LI>
+</UL>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2001-November/005061.html">
+ Whit Blauvelt's SoftRemote tips</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-October/015591.html">
+ Tim Wilson's tips (X.509)</A><A HREF="http://lists.freeswan.org/archives/users/2003-October/msg00607.html">
+ Workaround for a &quot;gotcha&quot;</A></P>
+<P><A HREF="http://jixen.tripod.com/#Rw-IRE-to-Fwan"> Jean-Francois
+ Nadeau's Practical Configuration (Road Warrior with PSK)</A>
+<BR><A HREF="http://www.terradoncommunications.com/security/whitepapers/safe_net-to-free_swan.pdf">
+ Terradon Communications' PDF (Road Warrior with PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-October/?????.html">
+ Seaan.net's PDF (Road Warrior to Subnet, with PSK)</A>
+<BR><A HREF="http://www.redbaronconsulting.com/freeswan/fswansafenet.pdf">
+ Red Baron Consulting's PDF (Road Warrior with X.509)</A></P>
+<P><A HREF="#safenet.top">Back to chart</A></P>
+<H3><A NAME="10_3_2">For<EM> Other Implementations</EM></A></H3>
+<H4><A NAME="6wind">6Wind</A></H4>
+<P><A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+ French page with configs (X.509)</A></P>
+<P><A HREF="#6wind.top">Back to chart</A></P>
+<H4><A NAME="alcatel">Alcatel Timestep</A></H4>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2002-June/011878.html">
+ Alain Sabban's settings (PSK or PSK road warrior; through static NAT)</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/1999/06/msg00100.html">
+ Derick Cassidy's configs (PSK)</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/1999/08/msg00194.html">
+ David Kerry's Timestep settings (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-August/013711.html">
+ Kevin Gerbracht's ipsec.conf (X.509)</A></P>
+<P><A HREF="#alcatel.top">Back to chart</A></P>
+<H4><A NAME="apple">Apple Macintosh System 10+</A></H4>
+<UL>
+<LI>Since the system is based on FreeBSD, this should interoperate<A HREF="#kame">
+ just like FreeBSD</A>.</LI>
+<LI> To use Appletalk over IPsec tunnels,<A HREF="http://lists.freeswan.org/pipermail/users/2001-November/005116.html">
+ run it over TCP/IP</A>, or use Open Door Networks' Shareway IP tool,<A HREF="http://lists.freeswan.org/pipermail/users/2001-November/005426.html">
+ described here.</A></LI>
+<LI>See also the<A HREF="#equinux"> Equinux VPN Tracker</A> for Mac OS
+ X.</LI>
+</UL>
+<P><A HREF="http://ipsec.math.ucla.edu/services/ipsec.html"> James
+ Carter's instructions (X.509, NAT-T)</A></P>
+<P><A HREF="#apple.top">Back to chart</A></P>
+<H4><A NAME="ashleylaurent">AshleyLaurent VPCom</A></H4>
+<P><A HREF="http://www.ashleylaurent.com/newsletter/01-28-00.htm">
+ Successful interop report, no details</A></P>
+<P><A HREF="#ashleylaurent.top">Back to chart</A></P>
+<H4><A NAME="borderware">Borderware</A></H4>
+<UL>
+<LI>I suspect the Borderware client is a rebranded Safenet. If that's
+ true, our<A HREF="#safenet"> Safenet section</A> will help.</LI>
+</UL>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2002-March/008288.html">
+ Philip Reetz' configs (PSK)</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/09/msg00217.html">
+ Borderware server does not support FreeS/WAN road warriors</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-February/007733.html">
+ Older Borderware may not support Diffie Hellman groups 2, 5</A>
+<BR></P>
+<P><A HREF="#borderware.top">Back to chart</A></P>
+<H4><A NAME="checkpoint">Check Point VPN-1 or FW-1</A></H4>
+<UL>
+<LI><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/02/msg00099.html">
+ Caveat about IP-range inclusion on Check Point.</A></LI>
+<LI> Some versions of Check Point may require an aggressive mode patch
+ to interoperate with FreeS/WAN.
+<BR><A HREF="http://www.freeswan.ca/code/super-freeswan"> Super
+ FreeS/WAN</A> now features this patch.
+<!--
+<A HREF="http://www.freeswan.ca/patches/aggressivemode">Steve Harvey's 
+aggressive mode patch for FreeS/WAN 1.5</A>
+-->
+</LI>
+<LI></LI>
+<LI>A Linux FreeS/WAN-Checkpoint connection may close after some time.
+ Try<A HREF="http://lists.freeswan.org/archives/users/2003-October/msg00293.html">
+ this tip</A> toward a workaround.</LI>
+</UL>
+<P><A HREF="http://www.fw-1.de/aerasec/ng/vpn-freeswan/CPNG+Linux-FreeSWAN.html">
+ AERAsec's Firewall-1 NG site (PSK, X.509, Road Warrior with X.509,
+ other algorithms)</A>
+<BR> &nbsp;&nbsp;&nbsp;&nbsp;<A HREF="http://www.fw-1.de/aerasec/ng/vpn-freeswan/CPNG+Linux-FreeSWAN.html#support-matrix">
+ AERAsec's detailed Check Point-FreeS/WAN support matrix</A>
+<BR><A HREF="http://support.checkpoint.com/kb/docs/public/firewall1/4_1/pdf/fw-linuxvpn.pdf">
+ Checkpoint.com PDF: Linux as a VPN Client to FW-1 (PSK)</A>
+<BR><A HREF="http://www.phoneboy.com"> PhoneBoy's Check Point FAQ (on
+ Check Point only, not FreeS/WAN)</A>
+<BR></P>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2001-August/002351.html">
+ Chris Harwell's tips FreeS/WAN configs (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-April/009362.html">
+ Daniel Tombeil's configs (PSK)</A></P>
+<P><A HREF="#checkpoint.top">Back to chart</A></P>
+<H4><A NAME="cisco">Cisco</A></H4>
+<UL>
+<LI> Cisco supports IPsec-over-UDP NAT traversal.</LI>
+<LI>Cisco VPN Client appears to use nonstandard IPsec and does not work
+ with FreeS/WAN.<A HREF="https://mj2.freeswan.org/archives/2003-August/maillist.html">
+ This message</A> concerns Cisco VPN Client 4.01.
+<!-- fix link -->
+</LI>
+<LI>A Linux FreeS/WAN-Cisco connection may close after some time.<A HREF="http://lists.freeswan.org/pipermail/users/2001-December/005758.html">
+ Here</A> is a workaround, and<A HREF="http://lists.freeswan.org/archives/users/2003-October/msg00293.html">
+ here</A> is another comment on the same subject.</LI>
+<LI><A HREF="http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120t/120t2/3desips.htm">
+Older Ciscos</A> purchased outside the United States may not have 3DES,
+ which FreeS/WAN requires.</LI>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2001-June/000406.html">
+RSA keying may not be possible between Cisco and FreeS/WAN.</A></LI>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2001-October/004357.html">
+In ipsec.conf, VPN3000 DN (distinguished name) must be in binary (X.509
+ only)</A></LI>
+</UL>
+<P><A HREF="http://rr.sans.org/encryption/cisco_router.php"> SANS
+ Institute HOWTO (PSK).</A> Detailed, with extensive references.
+<BR><A HREF="http://www.worldbank.ro/IPSEC/cisco-linux.txt"> Short HOWTO
+ (PSK)</A>
+<BR><A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+ French page with configs for Cisco IOS, PIX and VPN 3000 (X.509)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2001-August/002966.html">
+ Dave McFerren's sample configs (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2001-September/003422.html">
+ Wolfgang Tremmel's sample configs (PSK road warrior)</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/11/msg00578.html">
+ Old doc from Pete Davis, with William Watson's updated Tips (PSK)</A>
+<BR></P>
+<P><STRONG>Some PIX specific information:</STRONG>
+<BR><A HREF="http://www.wlug.org.nz/FreeSwanToCiscoPix"> Waikato Linux
+ Users' Group HOWTO. Nice detail (PSK)</A>
+<BR><A HREF="http://www.johnleach.co.uk/documents/freeswan-pix/freeswan-pix.html">
+ John Leach's configs (PSK)</A>
+<BR><A HREF="http://www.diverdown.cc/vpn/freeswanpix.html"> Greg
+ Robinson's settings (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-February/007901.html">
+ Scott's ipsec.conf for PIX (PSK, FreeS/WAN side only)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2001-October/003949.html">
+ Rick Trimble's PIX and FreeS/WAN settings (PSK)</A>
+<BR></P>
+<P><A href="http://www.cisco.com/public/support/tac"> Cisco VPN support
+ page</A>
+<BR><A href="http://www.ieng.com/warp/public/707/index.shtml#ipsec">
+ Cisco IPsec information page</A></P>
+<P><A HREF="#cisco.top">Back to chart</A></P>
+<H4><A NAME="equinux">Equinux VPN tracker (for Mac OS X)</A></H4>
+<UL>
+<LI>Graphical configurator for Mac OS X IPsec. May be an interface to
+ the<A HREF="#apple"> native Mac OS X IPsec</A>, which is essentially<A HREF="#kame">
+ KAME</A>.</LI>
+<LI>To use Appletalk over IPsec tunnels,<A HREF="http://lists.freeswan.org/pipermail/users/2001-November/005116.html">
+ run it over TCP/IP</A>, or use Open Door Networks' Shareway IP tool,<A HREF="http://lists.freeswan.org/pipermail/users/2001-November/005426.html">
+ described here.</A></LI>
+</UL>
+<P> Equinux provides<A HREF="http://www.equinux.com/download/HowTo_FreeSWAN.pdf">
+ this excellent interop PDF</A> (PSK, RSA, X.509).</P>
+<P><A HREF="#equinux.top">Back to chart</A></P>
+<H4><A NAME="fsecure">F-Secure</A></H4>
+<UL>
+<LI>
+<!-- <A HREF="http://lists.freeswan.org/pipermail/users/2002-February/007596.html"> -->
+ F-Secure supports IPsec-over-UDP NAT traversal.</LI>
+</UL>
+<P><A HREF="http://www.pingworks.de/tech/vpn/vpn.txt">pingworks.de's
+ &quot;Connecting F-Secure's VPN+ to Linux FreeS/WAN&quot; (PSK road warrior)</A>
+<BR> &nbsp;&nbsp;&nbsp;&nbsp;<A HREF="http://www.pingworks.de/tech/vpn/vpn.pdf">Same thing
+ as PDF</A>
+<BR><A HREF="http://www.exim.org/pipermail/linux-ipsec/Week-of-Mon-20010122/000061.html">
+ Success report, no detail (PSK)</A>
+<BR><A HREF="http://www.exim.org/pipermail/linux-ipsec/Week-of-Mon-20010122/000041.html">
+ Success report, no detail (Manual)</A></P>
+
+<!-- Other NAT traversers:
+http://lists.freeswan.org/pipermail/users/2002-April/009136.html
+and ssh sentinel:
+http://lists.freeswan.org/pipermail/users/2001-September/003108.html
+-->
+<P><A HREF="#fsecure.top">Back to chart</A></P>
+<H4><A NAME="gauntlet">Gauntlet GVPN</A></H4>
+<P><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/11/msg00535.html">
+ Richard Reiner's ipsec.conf (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-June/011434.html">
+ Might work without that pesky firewall... (PSK)</A>
+<BR>
+<!-- insert archive link -->
+ In late July, 2003 Alexandar Antik reported success interoperating
+ with Gauntlet 6.0 for Solaris (X.509). Unfortunately the message is not
+ properly archived at this time.</P>
+<P><A HREF="#gauntlet.top">Back to chart</A></P>
+<H4><A NAME="aix">IBM AIX</A></H4>
+<P><A HREF="http://www-1.ibm.com/servers/esdd/articles/security.html">
+ IBM's &quot;Built-In Network Security with AIX&quot; (PSK, X.509)</A>
+<BR><A HREF="http://www-1.ibm.com/servers/aix/products/ibmsw/security/vpn/faqandtips/#ques20">
+ IBM's tip: importing Linux FreeS/WAN settings into AIX's<VAR> ikedb</VAR>
+ (PSK)</A></P>
+<P><A HREF="#aix.top">Back to chart</A></P>
+<H4><A NAME="as400">IBM AS/400</A></H4>
+<UL>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2002-April/009106.html">
+ Road Warriors may act flaky</A>.</LI>
+</UL>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2002-September/014264.html">
+ Richard Welty's tips and tricks</A>
+<BR></P>
+<P><A HREF="#as400.top">Back to chart</A></P>
+<H4><A NAME="intel">Intel Shiva LANRover / Net Structure</A></H4>
+<UL>
+<LI>Intel Shiva LANRover is now known as Intel Net Structure.</LI>
+<LI><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/01/msg00298.html">
+ Shiva seems to have two modes: IPsec or the proprietary &quot;Shiva Tunnel&quot;.</A>
+ Of course, FreeS/WAN will only create IPsec tunnels.</LI>
+<LI><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/02/msg00293.html">
+ AH may not work for Shiva-FreeS/WAN.</A> That's OK, since FreeS/WAN has
+ phased out the use of AH.</LI>
+</UL>
+<P><A HREF="http://snowcrash.tdyc.com/freeswan/"> Snowcrash's configs
+ (PSK)</A>
+<BR><A HREF="http://www.opus1.com/vpn/index.html"> Old configs from an
+ interop (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2001-October/003831.html">
+ The day Shiva tickled a Pluto bug (PSK)</A>
+<BR> &nbsp;&nbsp;&nbsp;&nbsp;<A HREF="http://lists.freeswan.org/pipermail/users/2001-October/004270.html">
+ Follow up: success!</A></P>
+<P><A HREF="#intel.top">Back to chart</A></P>
+<H4><A NAME="lancom">LanCom (formerly ELSA)</A></H4>
+<UL>
+<LI>This router is popular in Germany.</LI>
+</UL>
+<P> Jakob Curdes successfully created a PSK connection with the LanCom
+ 1612 in August 2003.
+<!-- add ML link when it appears -->
+</P>
+<P><A HREF="#lancom.top">Back to chart</A></P>
+<H4><A NAME="linksys">Linksys</A></H4>
+<UL>
+<LI>Linksys may be used as an IPsec tunnel endpoint,<STRONG> OR</STRONG>
+ as a router in &quot;IPsec passthrough&quot; mode, so that the IPsec tunnel
+ passes through the Linksys.</LI>
+</UL>
+<H5>As tunnel endpoint</H5>
+<P><A HREF="http://www.freeswan.ca/docs/BEFVP41/"> Ken Bantoft's
+ instructions (Road Warrior with PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-February/007814.html">
+ Nate Carlson's caveats</A></P>
+<H5>In IPsec passthrough mode</H5>
+<P><A HREF="http://www-ec.njit.edu/~rxt1077/Howto.txt"> Sample HOWTO
+ through a Linksys Router</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2002/02/msg00114.html">
+ Nadeem Hasan's configs</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2002/02/msg00180.html">
+ Brock Nanson's tips</A>
+<BR></P>
+<P><A HREF="#linksys.top">Back to chart</A></P>
+<H4><A NAME="lucent">Lucent</A></H4>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2002-May/010976.html">
+ Partial success report; see also the next message in thread</A></P>
+
+<!-- section done -->
+<P><A HREF="#lucent.top">Back to chart</A></P>
+<H4><A NAME="netasq">Netasq</A></H4>
+<P><A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+ French page with configs (X.509)</A></P>
+
+<!-- section done -->
+<P><A HREF="#netasq.top">Back to chart</A></P>
+<H4><A NAME="netcelo">Netcelo</A></H4>
+<P><A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+ French page with configs (X.509)</A>
+<!-- section done -->
+</P>
+<P><A HREF="#netcelo.top">Back to chart</A></P>
+<H4><A NAME="netgear">Netgear fvs318</A></H4>
+<UL>
+<LI>With a recent Linux FreeS/WAN, you will require the latest (12/2002)
+ Netgear firmware, which supports Diffie-Hellman (DH) group 2. For
+ security reasons, we phased out DH 1 after Linux FreeS/WAN 1.5.</LI>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2002-June/011833.html">
+ This message</A> reports the incompatibility between Linux FreeS/WAN
+ 1.6+ and Netgear fvs318 without the firmware upgrade.</LI>
+<LI>We believe Linux FreeS/WAN 1.5 and earlier will interoperate with
+ any NetGear firmware.</LI>
+</UL>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2003-February/017891.html">
+ John Morris' setup (PSK)</A></P>
+<P><A HREF="#netgear.top">Back to chart</A></P>
+<H4><A NAME="netscreen">Netscreen 100 or 5xp</A></H4>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2002-August/013409.html">
+ Errol Neal's settings (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-October/015265.html">
+ Corey Rogers' configs (PSK, no PFS)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-August/013051.html">
+ Jordan Share's configs (PSK, 2 subnets, through static NAT)</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/08/msg00404.html">
+ Set src proxy_id to your protected subnet/mask</A>
+<BR><A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+ French page with ipsec.conf, Netscreen screen shots (X.509, may need to
+ revert to PSK...)</A></P>
+<P><A HREF="http://archives.neohapsis.com/archives/sf/linux/2001-q2/0123.html">
+ A report of a company using Netscreen with FreeS/WAN on a large scale
+ (FreeS/WAN road warriors?)</A></P>
+<P><A HREF="#netscreen.top">Back to chart</A></P>
+<H4><A NAME="nortel">Nortel Contivity</A></H4>
+<UL>
+<LI> Nortel supports IPsec-over-UDP NAT traversal.</LI>
+<LI><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/02/msg00417.html">
+ Some older versions of Contivity and FreeS/WAN will not communicate.</A>
+</LI>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2002-May/010924.html">
+ FreeS/WAN cannot be used as a &quot;client&quot; to a Nortel Contivity server,
+ but can be used as a branch-office tunnel.</A></LI>
+
+<!--  Probably obsoleted by Ken's post
+<LI>
+(Matthias siebler from old interop)
+At one point you could not configure Nortel-FreeS/WAN tunnels as 
+"Client Tunnels" since FreeS/WAN does not support Aggressive Mode.
+Current status of this problem: unknown.
+<LI>
+<A HREF="http://lists.freeswan.org/pipermail/users/2001-November/004612.html">
+How do we map group and user passwords onto the data that FreeS/WAN wants?
+</A>
+</LI>
+-->
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2002-October/015455.html">
+ Contivity does not send Distinguished Names in the order FS wants them
+ (X.509).</A></LI>
+<LI><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/03/msg00137.html">
+ Connections may time out after 30-40 minutes idle.</A></LI>
+</UL>
+<P><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/03/msg00137.html">
+ JJ Streicher-Bremer's mini HOWTO for old new software. (PSK with two
+ subnets)</A>
+<BR><A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+ French page with configs (X.509)</A>. This succeeds using the above
+ X.509 tip.</P>
+
+<!-- I could do more searching but this is a solid start. -->
+<P><A HREF="#nortel.top">Back to chart</A></P>
+<H4><A NAME="radguard">Radguard</A></H4>
+<P><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/05/msg00009.html">
+ Marko Hausalo's configs (PSK).</A> Note: These do create a connection,
+ as you can see by &quot;IPsec SA established&quot;.
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-October/???.html">
+ Claudia Schmeing's comments</A></P>
+<P><A HREF="#radguard.top">Back to chart</A></P>
+<H4><A NAME="raptor">Raptor (NT or Solaris)</A></H4>
+<P></P>
+<UL>
+<LI>Now known as Symantec Enterprise Firewall.</LI>
+<LI>The Raptor does not normally come with X.509, but this may be
+ available as an add-on.</LI>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2002-May/010256.html">
+ Raptor requires alphanumberic PSK values, whereas FreeS/WAN uses hex.</A>
+</LI>
+<LI>Raptor's tunnel endpoint may be a host, subnet or group of subnets
+ (see<A HREF="http://lists.freeswan.org/pipermail/design/2001-November/001295.html">
+ this message</A> ). FreeS/WAN cannot handle the group of subnets; you
+ must create separate connections for each in order to interoperate.</LI>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2002-May/010113.html">
+ Some versions of Raptor accept only single DES.</A> According to this
+ German message,<A HREF="http://radawana.cg.tuwien.ac.at/mail-archives/lll/200012/msg00065.html">
+ the Raptor Mobile Client demo offers single DES only.</A></LI>
+</UL>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2002-January/006935.html">
+ Peter Mazinger's settings (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2001-November/005522.html">
+ Peter Gerland's configs (PSK)</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/07/msg00597.html">
+ Charles Griebel's configs (PSK).</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-July/012275.html">
+ Lumir Srch's tips (PSK)</A></P>
+<P><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/05/msg00214.html">
+ John Hardy's configs (Manual)</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/01/msg00236.html">
+ Older Raptors want 3DES keys in 3 parts (Manual).</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/06/msg00480.html">
+ Different keys for each direction? (Manual)</A>
+<BR></P>
+<P><A HREF="#raptor.top">Back to chart</A></P>
+<H4><A NAME="redcreek">Redcreek Ravlin</A></H4>
+<UL>
+<LI>Known issue #1: The Ravlin expects a quick mode renegotiation right
+ after every Main Mode negotiation.</LI>
+<LI> Known issue #2: The Ravlin tries to negotiate a zero connection
+ lifetime, which it takes to mean &quot;infinite&quot;.<A HREF="http://www.bear-cave.org.uk/linux/ravlin/">
+ Jim Hague's patch</A> addresses both issues.</LI>
+<LI><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/03/msg00191.html">
+ Interop works with Ravlin Firmware &gt; 3.33. Includes tips (PSK).</A></LI>
+</UL>
+<P><A HREF="#redcreek.top">Back to chart</A></P>
+<H4><A NAME="sonicwall">SonicWall</A></H4>
+<UL>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2001-June/000998.html">
+ Sonicwall cannot be used for Road Warrior setups</A></LI>
+<LI> At one point,<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/05/msg00217.html">
+ only Sonicwall PRO supported triple DES</A>.</LI>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2002-March/008600.html">
+ Older Sonicwalls (before Nov 2001) feature Diffie Hellman group 1 only</A>
+.</LI>
+</UL>
+<P><A HREF="http://www.xinit.cx/docs/freeswan.html"> Paul Wouters'
+ config (PSK)</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/02/msg00073.html">
+ Dilan Arumainathan's configuration (PSK)</A>
+<BR><A HREF="http://www.gravitas.co.uk/vpndebug"> Dariush's setup...
+ only opens one way (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2003-July/022302.html">
+ Andreas Steffen's tips (X.509)</A>
+<BR></P>
+<P><A HREF="#sonicwall.top">Back to chart</A></P>
+<H4><A NAME="sun">Sun Solaris</A></H4>
+<UL>
+<LI> Solaris 8+ has a native (in kernel) IPsec implementation.</LI>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2002-May/010503.html">
+ Solaris does not seem to support tunnel mode, but you can make IP-in-IP
+ tunnels instead, like this.</A></LI>
+</UL>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2003-June/022216.html">
+ Reports of some successful interops</A> from a fellow @sun.com. See
+ also<A HREF="http://lists.freeswan.org/pipermail/users/2003-July/022247.html">
+ these follow up posts</A>.
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/03/msg00332.html">
+ Aleks Shenkman's configs (Manual in transport mode)</A>
+<BR>
+<!--sparc 64 stuff goes where?-->
+</P>
+<P><A HREF="#solaris.top">Back to chart</A></P>
+<H4><A NAME="symantec">Symantec</A></H4>
+<UL>
+<LI>The Raptor, covered<A HREF="#raptor"> above</A>, is now known as
+ Symantec Enterprise Firewall.</LI>
+<LI>Symantec's &quot;distinguished name&quot; is a KEY_ID. See Andreas Steffen's
+ post, below.</LI>
+</UL>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2002-April/009037.html">
+ Andreas Steffen's configs for Symantec 200R (PSK)</A></P>
+<P><A HREF="#symantec.top">Back to chart</A></P>
+<H4><A NAME="watchguard">Watchguard Firebox</A></H4>
+<UL>
+<LI>Automatic keying works with WatchGuard 5.0+ only.</LI>
+<LI>Seen to interoperate with WatchGuard 1000, II, III; firmware v. 5,
+ 6..</LI>
+<LI>For manual keying, Watchguard's Policy Manager expects SPI numbers
+ and encryption and authentication keys in decimal (not hex).</LI>
+</UL>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2002-July/012595.html">
+ WatchGuard's HOWTO (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-August/013342.html">
+ Ronald C. Riviera's Settings (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/archives/users/2003-October/msg00179.html">
+ Walter Wickersham's Notes (PSK)</A>
+<BR><A HREF="http://lists.freeswan.org/pipermail/users/2002-October/015587.html">
+ Max Enders' Configs (Manual)</A></P>
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2002-April/009404.html">
+ Old known issue with auto keying</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/02/msg00124.html">
+ Tips on key generation and format (Manual)</A>
+<BR></P>
+<P><A HREF="#watchguard.top">Back to chart</A></P>
+<H4><A NAME="xedia">Xedia Access Point/QVPN</A></H4>
+<P><A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/12/msg00520.html">
+ Hybrid IPsec/L2TP connection settings (X.509)</A>
+<BR><A HREF="http://www.sandelman.ottawa.on.ca/ipsec/1999/08/msg00140.html">
+ Xedia's LAN-LAN links don't use multiple tunnels</A>
+<BR> &nbsp;&nbsp;&nbsp;&nbsp;<A HREF="http://www.sandelman.ottawa.on.ca/ipsec/1999/08/msg00140.html">
+ That explanation, continued</A></P>
+<P><A HREF="#xedia.top">Back to chart</A></P>
+<H4><A NAME="zyxel">Zyxel</A></H4>
+<UL>
+<LI>The Zyxel Zywall is a rebranded SSH Sentinel box. See also our
+ section on<A HREF="glossary.html#ssh"> SSH</A>.</LI>
+<LI>There seems to be a problem with keeping this connection alive. This
+ is caused at the Zyxel end. See this brief<A HREF="http://lists.freeswan.org/archives/users/2003-October/msg00141.html">
+ discussion and solution.</A></LI>
+</UL>
+<P><A HREF="http://www.zyxel.com/support/supportnote/zywall/app/zw_freeswan.htm">
+ Zyxel's Zywall to FreeS/WAN instructions (PSK)</A>
+<BR><A HREF="http://www.zyxel.com/support/supportnote/p652/app/zw_freeswan.htm">
+ Zyxel's Prestige to FreeS/WAN instructions (PSK)</A>. Note: not all
+ Prestige versions include VPN software.
+<BR><A HREF="http://www.lancry.net/techdocs/freeswan-zyxel.txt"> Fabrice
+ Cahen's HOWTO (PSK)</A>
+<BR> &nbsp;&nbsp;&nbsp;&nbsp;</P>
+<P><A HREF="#zyxel.top">Back to chart</A></P>
+
+<!-- SAMPLE ENTRY
+
+<H4><A NAME="timestep">Timestep</A></H4>
+
+<P>Text goes here.
+</P>
+
+-->
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="compat.html">Previous</A>
+<A HREF="performance.html">Next</A>
+</BODY>
+</HTML>
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
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+PRE { font-family: monospace }
+--></STYLE>
+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="upgrading.html">Next</A>
+<HR>
+<H1><A name="intro">Introduction</A></H1>
+<P>This section gives an overview of:</P>
+<UL>
+<LI>what IP Security (IPsec) does</LI>
+<LI>how IPsec works</LI>
+<LI>why we are implementing it for Linux</LI>
+<LI>how this implementation works</LI>
+</UL>
+<P>This section is intended to cover only the essentials,<EM> things you
+ should know before trying to use FreeS/WAN.</EM></P>
+<P>For more detailed background information, see the<A href="politics.html#politics">
+ history and politics</A> and<A href="ipsec.html#ipsec.detail"> IPsec
+ protocols</A> sections.</P>
+<H2><A name="ipsec.intro">IPsec, Security for the Internet Protocol</A></H2>
+<P>FreeS/WAN is a Linux implementation of the IPsec (IP security)
+ protocols. IPsec provides<A href="glossary.html#encryption"> encryption</A>
+ and<A href="glossary.html#authentication"> authentication</A> services
+ at the IP (Internet Protocol) level of the network protocol stack.</P>
+<P>Working at this level, IPsec can protect any traffic carried over IP,
+ unlike other encryption which generally protects only a particular
+ higher-level protocol --<A href="glossary.html#PGP"> PGP</A> for mail,<A
+href="glossary.html#SSH"> SSH</A> for remote login,<A href="glossary.html#SSL">
+ SSL</A> for web work, and so on. This approach has both considerable
+ advantages and some limitations. For discussion, see our<A href="ipsec.html#others">
+ IPsec section</A></P>
+<P>IPsec can be used on any machine which does IP networking. Dedicated
+ IPsec gateway machines can be installed wherever required to protect
+ traffic. IPsec can also run on routers, on firewall machines, on
+ various application servers, and on end-user desktop or laptop
+ machines.</P>
+<P>Three protocols are used</P>
+<UL>
+<LI><A href="glossary.html#AH">AH</A> (Authentication Header) provides a
+ packet-level authentication service</LI>
+<LI><A href="glossary.html#ESP">ESP</A> (Encapsulating Security Payload)
+ provides encryption plus authentication</LI>
+<LI><A href="glossary.html#IKE">IKE</A> (Internet Key Exchange)
+ negotiates connection parameters, including keys, for the other two</LI>
+</UL>
+<P>Our implementation has three main parts:</P>
+<UL>
+<LI><A href="glossary.html#KLIPS">KLIPS</A> (kernel IPsec) implements
+ AH, ESP, and packet handling within the kernel</LI>
+<LI><A href="glossary.html#Pluto">Pluto</A> (an IKE daemon) implements
+ IKE, negotiating connections with other systems</LI>
+<LI>various scripts provide an adminstrator's interface to the machinery</LI>
+</UL>
+<P>IPsec is optional for the current (version 4) Internet Protocol.
+ FreeS/WAN adds IPsec to the Linux IPv4 network stack. Implementations
+ of<A href="glossary.html#ipv6.gloss"> IP version 6</A> are required to
+ include IPsec. Work toward integrating FreeS/WAN into the Linux IPv6
+ stack has<A href="compat.html#ipv6"> started</A>.</P>
+<P>For more information on IPsec, see our<A href="ipsec.html#ipsec.detail">
+ IPsec protocols</A> section, our collection of<A href="web.html#ipsec.link">
+ IPsec links</A> or the<A href="rfc.html#RFC"> RFCs</A> which are the
+ official definitions of these protocols.</P>
+<H3><A name="intro.interop">Interoperating with other IPsec
+ implementations</A></H3>
+<P>IPsec is designed to let different implementations work together. We
+ provide:</P>
+<UL>
+<LI>a<A href="web.html#implement"> list</A> of some other
+ implementations</LI>
+<LI>information on<A href="interop.html#interop"> using FreeS/WAN with
+ other implementations</A></LI>
+</UL>
+<P>The VPN Consortium fosters cooperation among implementers and
+ interoperability among implementations. Their<A href="http://www.vpnc.org/">
+ web site</A> has much more information.</P>
+<H3><A name="advantages">Advantages of IPsec</A></H3>
+<P>IPsec has a number of security advantages. Here are some
+ independently written articles which discuss these:</P>
+<P><A HREF="http://www.sans.org/rr/"> SANS institute papers</A>. See the
+ section on Encryption &amp;VPNs.
+<BR><A HREF="http://www.cisco.com/en/US/netsol/ns110/ns170/ns171/ns128/networking_solutions_white_papers_list.html">
+ Cisco's white papers on &quot;Networking Solutions&quot;</A>.
+<BR><A HREF="http://iscs.sourceforge.net/HowWhyBrief/HowWhyBrief.html">
+ Advantages of ISCS (Linux Integrated Secure Communications System;
+ includes FreeS/WAN and other software)</A>.</P>
+<H3><A name="applications">Applications of IPsec</A></H3>
+<P>Because IPsec operates at the network layer, it is remarkably
+ flexible and can be used to secure nearly any type of Internet traffic.
+ Two applications, however, are extremely widespread:</P>
+<UL>
+<LI>a<A href="glossary.html#VPN"> Virtual Private Network</A>, or VPN,
+ allows multiple sites to communicate securely over an insecure Internet
+ by encrypting all communication between the sites.</LI>
+<LI>&quot;Road Warriors&quot; connect to the office from home, or perhaps from a
+ hotel somewhere</LI>
+</UL>
+<P>There is enough opportunity in these applications that vendors are
+ flocking to them. IPsec is being built into routers, into firewall
+ products, and into major operating systems, primarily to support these
+ applications. See our<A href="web.html#implement"> list</A> of
+ implementations for details.</P>
+<P>We support both of those applications, and various less common IPsec
+ applications as well, but we also add one of our own:</P>
+<UL>
+<LI>opportunistic encryption, the ability to set up FreeS/WAN gateways
+ so that any two of them can encrypt to each other, and will do so
+ whenever packets pass between them.</LI>
+</UL>
+<P>This is an extension we are adding to the protocols. FreeS/WAN is the
+ first prototype implementation, though we hope other IPsec
+ implementations will adopt the technique once we demonstrate it. See<A href="#goals">
+ project goals</A> below for why we think this is important.</P>
+<P>A somewhat more detailed description of each of these applications is
+ below. Our<A href="quickstart.html#quick_guide"> quickstart</A> section
+ will show you how to build each of them.</P>
+<H4><A name="makeVPN">Using secure tunnels to create a VPN</A></H4>
+<P>A VPN, or<STRONG> V</STRONG>irtual<STRONG> P</STRONG>rivate<STRONG> N</STRONG>
+etwork lets two networks communicate securely when the only connection
+ between them is over a third network which they do not trust.</P>
+<P>The method is to put a security gateway machine between each of the
+ communicating networks and the untrusted network. The gateway machines
+ encrypt packets entering the untrusted net and decrypt packets leaving
+ it, creating a secure tunnel through it.</P>
+<P>If the cryptography is strong, the implementation is careful, and the
+ administration of the gateways is competent, then one can reasonably
+ trust the security of the tunnel. The two networks then behave like a
+ single large private network, some of whose links are encrypted tunnels
+ through untrusted nets.</P>
+<P>Actual VPNs are often more complex. One organisation may have fifty
+ branch offices, plus some suppliers and clients, with whom it needs to
+ communicate securely. Another might have 5,000 stores, or 50,000
+ point-of-sale devices. The untrusted network need not be the Internet.
+ All the same issues arise on a corporate or institutional network
+ whenever two departments want to communicate privately with each other.</P>
+<P>Administratively, the nice thing about many VPN setups is that large
+ parts of them are static. You know the IP addresses of most of the
+ machines involved. More important, you know they will not change on
+ you. This simplifies some of the admin work. For cases where the
+ addresses do change, see the next section.</P>
+<H4><A name="road.intro">Road Warriors</A></H4>
+<P>The prototypical &quot;Road Warrior&quot; is a traveller connecting to home
+ base from a laptop machine. Administratively, most of the same problems
+ arise for a telecommuter connecting from home to the office, especially
+ if the telecommuter does not have a static IP address.</P>
+<P>For purposes of this document:</P>
+<UL>
+<LI>anyone with a dynamic IP address is a &quot;Road Warrior&quot;.</LI>
+<LI>any machine doing IPsec processing is a &quot;gateway&quot;. Think of the
+ single-user road warrior machine as a gateway with a degenerate subnet
+ (one machine, itself) behind it.</LI>
+</UL>
+<P>These require somewhat different setup than VPN gateways with static
+ addresses and with client systems behind them, but are basically not
+ problematic.</P>
+<P>There are some difficulties which appear for some road warrior
+ connections:</P>
+<UL>
+<LI>Road Wariors who get their addresses via DHCP may have a problem.
+ FreeS/WAN can quite happily build and use a tunnel to such an address,
+ but when the DHCP lease expires, FreeS/WAN does not know that. The
+ tunnel fails, and the only recovery method is to tear it down and
+ re-build it.</LI>
+<LI>If<A href="glossary.html#NAT.gloss"> Network Address Translation</A>
+ (NAT) is applied between the two IPsec Gateways, this breaks IPsec.
+ IPsec authenticates packets on an end-to-end basis, to ensure they are
+ not altered en route. NAT rewrites packets as they go by. See our<A href="firewall.html#NAT">
+ firewalls</A> document for details.</LI>
+</UL>
+<P>In most situations, however, FreeS/WAN supports road warrior
+ connections just fine.</P>
+<H4><A name="opp.intro">Opportunistic encryption</A></H4>
+<P>One of the reasons we are working on FreeS/WAN is that it gives us
+ the opportunity to add what we call opportuntistic encryption. This
+ means that any two FreeS/WAN gateways will be able to encrypt their
+ traffic, even if the two gateway administrators have had no prior
+ contact and neither system has any preset information about the other.</P>
+<P>Both systems pick up the authentication information they need from
+ the<A href="glossary.html#DNS"> DNS</A> (domain name service), the
+ service they already use to look up IP addresses. Of course the
+ administrators must put that information in the DNS, and must set up
+ their gateways with opportunistic encryption enabled. Once that is
+ done, everything is automatic. The gateways look for opportunities to
+ encrypt, and encrypt whatever they can. Whether they also accept
+ unencrypted communication is a policy decision the administrator can
+ make.</P>
+<P>This technique can give two large payoffs:</P>
+<UL>
+<LI>It reduces the administrative overhead for IPsec enormously. You
+ configure your gateway and thereafter everything is automatic. The need
+ to configure the system on a per-tunnel basis disappears. Of course,
+ FreeS/WAN allows specifically configured tunnels to co-exist with
+ opportunistic encryption, but we hope to make them unnecessary in most
+ cases.</LI>
+<LI>It moves us toward a more secure Internet, allowing users to create
+ an environment where message privacy is the default. All messages can
+ be encrypted, provided the other end is willing to co-operate. See our<A
+href="politics.html#politics"> history and politics of cryptography</A>
+ section for discussion of why we think this is needed.</LI>
+</UL>
+<P>Opportunistic encryption is not (yet?) a standard part of the IPsec
+ protocols, but an extension we are proposing and demonstrating. For
+ details of our design, see<A href="#applied"> links</A> below.</P>
+<P>Only one current product we know of implements a form of
+ opportunistic encryption.<A href="web.html#ssmail"> Secure sendmail</A>
+ will automatically encrypt server-to-server mail transfers whenever
+ possible.</P>
+<H3><A name="types">The need to authenticate gateways</A></H3>
+<P>A complication, which applies to any type of connection -- VPN, Road
+ Warrior or opportunistic -- is that a secure connection cannot be
+ created magically.<EM> There must be some mechanism which enables the
+ gateways to reliably identify each other.</EM> Without this, they
+ cannot sensibly trust each other and cannot create a genuinely secure
+ link.</P>
+<P>Any link they do create without some form of<A href="glossary.html#authentication">
+ authentication</A> will be vulnerable to a<A href="glossary.html#middle">
+ man-in-the-middle attack</A>. If<A href="glossary.html#alicebob"> Alice
+ and Bob</A> are the people creating the connection, a villian who can
+ re-route or intercept the packets can pose as Alice while talking to
+ Bob and pose as Bob while talking to Alice. Alice and Bob then both
+ talk to the man in the middle, thinking they are talking to each other,
+ and the villain gets everything sent on the bogus &quot;secure&quot; connection.</P>
+<P>There are two ways to build links securely, both of which exclude the
+ man-in-the middle:</P>
+<UL>
+<LI>with<STRONG> manual keying</STRONG>, Alice and Bob share a secret
+ key (which must be transmitted securely, perhaps in a note or via PGP
+ or SSH) to encrypt their messages. For FreeS/WAN, such keys are stored
+ in the<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf(5)</A> file. Of
+ course, if an enemy gets the key, all is lost.</LI>
+<LI>with<STRONG> automatic keying</STRONG>, the two systems authenticate
+ each other and negotiate their own secret keys. The keys are
+ automatically changed periodically.</LI>
+</UL>
+<P>Automatic keying is much more secure, since if an enemy gets one key
+ only messages between the previous re-keying and the next are exposed.
+ It is therefore the usual mode of operation for most IPsec deployment,
+ and the mode we use in our setup examples. FreeS/WAN does support
+ manual keying for special circumstanes. See this<A href="adv_config.html#prodman">
+ section</A>.</P>
+<P>For automatic keying, the two systems must authenticate each other
+ during the negotiations. There is a choice of methods for this:</P>
+<UL>
+<LI>a<STRONG> shared secret</STRONG> provides authentication. If Alice
+ and Bob are the only ones who know a secret and Alice recives a message
+ which could not have been created without that secret, then Alice can
+ safely believe the message came from Bob.</LI>
+<LI>a<A href="glossary.html#public"> public key</A> can also provide
+ authentication. If Alice receives a message signed with Bob's private
+ key (which of course only he should know) and she has a trustworthy
+ copy of his public key (so that she can verify the signature), then she
+ can safely believe the message came from Bob.</LI>
+</UL>
+<P>Public key techniques are much preferable, for reasons discussed<A href="config.html#choose">
+ later</A>, and will be used in all our setup examples. FreeS/WAN does
+ also support auto-keying with shared secret authentication. See this<A href="adv_config.html#prodsecrets">
+ section</A>.</P>
+<H2><A name="project">The FreeS/WAN project</A></H2>
+<P>For complete information on the project, see our web site,<A href="http://liberty.freeswan.org">
+ freeswan.org</A>.</P>
+<P>In summary, we are implementing the<A href="glossary.html#IPsec">
+ IPsec</A> protocols for Linux and extending them to do<A href="glossary.html#carpediem">
+ opportunistic encryption</A>.</P>
+<H3><A name="goals">Project goals</A></H3>
+<P>Our overall goal in FreeS/WAN is to make the Internet more secure and
+ more private.</P>
+<P>Our IPsec implementation supports VPNs and Road Warriors of course.
+ Those are important applications. Many users will want FreeS/WAN to
+ build corporate VPNs or to provide secure remote access.</P>
+<P>However, our goals in building it go beyond that. We are trying to
+ help<STRONG> build security into the fabric of the Internet</STRONG> so
+ that anyone who choses to communicate securely can do so, as easily as
+ they can do anything else on the net.</P>
+<P>More detailed objectives are:</P>
+<UL>
+<LI>extend IPsec to do<A href="glossary.html#carpediem"> opportunistic
+ encryption</A> so that
+<UL>
+<LI>any two systems can secure their communications without a
+ pre-arranged connection</LI>
+<LI><STRONG>secure connections can be the default</STRONG>, falling back
+ to unencrypted connections only if:
+<UL>
+<LI><EM>both</EM> the partner is not set up to co-operate on securing
+ the connection</LI>
+<LI><EM>and</EM> your policy allows insecure connections</LI>
+</UL>
+</LI>
+<LI>a significant fraction of all Internet traffic is encrypted</LI>
+<LI>wholesale monitoring of the net (<A href="politics.html#intro.poli">
+examples</A>) becomes difficult or impossible</LI>
+</UL>
+</LI>
+<LI>help make IPsec widespread by providing an implementation with no
+ restrictions:
+<UL>
+<LI>freely available in source code under the<A href="glossary.html#GPL">
+ GNU General Public License</A></LI>
+<LI>running on a range of readily available hardware</LI>
+<LI>not subject to US or other nations'<A href="politics.html#exlaw">
+ export restrictions</A>.
+<BR> Note that in order to avoid<EM> even the appearance</EM> of being
+ subject to those laws, the project cannot accept software contributions
+ --<EM> not even one-line bug fixes</EM> -- from US residents or
+ citizens.</LI>
+</UL>
+</LI>
+<LI>provide a high-quality IPsec implementation for Linux
+<UL>
+<LI>portable to all CPUs Linux supports:<A href="compat.html#CPUs">
+ (current list)</A></LI>
+<LI>interoperable with other IPsec implementations:<A href="interop.html#interop">
+ (current list)</A></LI>
+</UL>
+</LI>
+</UL>
+<P>If we can get opportunistic encryption implemented and widely
+ deployed, then it becomes impossible for even huge well-funded agencies
+ to monitor the net.</P>
+<P>See also our section on<A href="politics.html#politics"> history and
+ politics</A> of cryptography, which includes our project leader's<A href="politics.html#gilmore">
+ rationale</A> for starting the project.</P>
+<H3><A name="staff">Project team</A></H3>
+<P>Two of the team are from the US and can therefore contribute no code:</P>
+<UL>
+<LI>John Gilmore: founder and policy-maker (<A href="http://www.toad.com/gnu/">
+home page</A>)</LI>
+<LI>Hugh Daniel: project manager, Most Demented Tester, and occasionally
+ Pointy-Haired Boss</LI>
+</UL>
+<P>The rest of the team are Canadians, working in Canada. (<A href="politics.html#status">
+Why Canada?</A>)</P>
+<UL>
+<LI>Hugh Redelmeier:<A href="glossary.html#Pluto"> Pluto daemon</A>
+ programmer</LI>
+<LI>Richard Guy Briggs:<A href="glossary.html#KLIPS"> KLIPS</A>
+ programmer</LI>
+<LI>Michael Richardson: hacker without portfolio</LI>
+<LI>Claudia Schmeing: documentation</LI>
+<LI>Sam Sgro: technical support via the<A href="mail.html#lists">
+ mailing lists</A></LI>
+</UL>
+<P>The project is funded by civil libertarians who consider our goals
+ worthwhile. Most of the team are paid for this work.</P>
+<P>People outside this core team have made substantial contributions.
+ See</P>
+<UL>
+<LI>our<A href="../CREDITS"> CREDITS</A> file</LI>
+<LI>the<A href="web.html#patch"> patches and add-ons</A> section of our
+ web references file</LI>
+<LI>lists below of user-written<A href="#howto"> HowTos</A> and<A href="#applied">
+ other papers</A></LI>
+</UL>
+<P>Additional contributions are welcome. See the<A href="faq.html#contrib.faq">
+ FAQ</A> for details.</P>
+<H2><A name="products">Products containing FreeS/WAN</A></H2>
+<P>Unfortunately the<A href="politics.html#exlaw"> export laws</A> of
+ some countries restrict the distribution of strong cryptography.
+ FreeS/WAN is therefore not in the standard Linux kernel and not in all
+ CD or web distributions.</P>
+<P>FreeS/WAN is, however, quite widely used. Products we know of that
+ use it are listed below. We would appreciate hearing, via the<A href="mail.html#lists">
+ mailing lists</A>, of any we don't know of.</P>
+<H3><A name="distwith">Full Linux distributions</A></H3>
+<P>FreeS/WAN is included in various general-purpose Linux distributions,
+ mostly from countries (shown in brackets) with more sensible laws:</P>
+<UL>
+<LI><A href="http://www.suse.com/">SuSE Linux</A> (Germany)</LI>
+<LI><A href="http://www.conectiva.com">Conectiva</A> (Brazil)</LI>
+<LI><A href="http://www.linux-mandrake.com/en/">Mandrake</A> (France)</LI>
+<LI><A href="http://www.debian.org">Debian</A></LI>
+<LI>the<A href="http://www.pld.org.pl/"> Polish(ed) Linux Distribution</A>
+ (Poland)</LI>
+<LI><A>Best Linux</A> (Finland)</LI>
+</UL>
+<P>For distributions which do not include FreeS/WAN and are not Redhat
+ (which we develop and test on), there is additional information in our<A
+href="compat.html#otherdist"> compatibility</A> section.</P>
+<P>The server edition of<A href="http://www.corel.com"> Corel</A> Linux
+ (Canada) also had FreeS/WAN, but Corel have dropped that product line.</P>
+<H3><A name="kernel_dist">Linux kernel distributions</A></H3>
+<UL>
+<LI><A href="http://sourceforge.net/projects/wolk/">Working Overloaded
+ Linux Kernel (WOLK)</A></LI>
+</UL>
+<H3><A name="office_dist">Office server distributions</A></H3>
+<P>FreeS/WAN is also included in several distributions aimed at the
+ market for turnkey business servers:</P>
+<UL>
+<LI><A href="http://www.e-smith.com/">e-Smith</A> (Canada), which has
+ recently been acquired and become the Network Server Solutions group of<A
+href="http://www.mitel.com/"> Mitel Networks</A> (Canada)</LI>
+<LI><A href="http://www.clarkconnect.org/">ClarkConnect</A> from Point
+ Clark Networks (Canada)</LI>
+<LI><A href="http://www.trustix.net/">Trustix Secure Linux</A> (Norway)</LI>
+</UL>
+<H3><A name="fw_dist">Firewall distributions</A></H3>
+<P>Several distributions intended for firewall and router applications
+ include FreeS/WAN:</P>
+<UL>
+<LI>The<A href="http://www.linuxrouter.org/"> Linux Router Project</A>
+ produces a Linux distribution that will boot from a single floppy. The<A
+href="http://leaf.sourceforge.net"> LEAF</A> firewall project provides
+ several different LRP-based firewall packages. At least one of them,
+ Charles Steinkuehler's Dachstein, includes FreeS/WAN with X.509
+ patches.</LI>
+<LI>there are several distributions bootable directly from CD-ROM,
+ usable on a machine without hard disk.
+<UL>
+<LI>Dachstein (see above) can be used this way</LI>
+<LI><A href="http://www.gibraltar.at/">Gibraltar</A> is based on Debian
+ GNU/Linux.</LI>
+<LI>at time of writing,<A href="www.xiloo.com"> Xiloo</A> is available
+ only in Chinese. An English version is expected.</LI>
+</UL>
+</LI>
+<LI><A href="http://www.astaro.com/products/index.html">Astaro Security
+ Linux</A> includes FreeS/WAN. It has some web-based tools for managing
+ the firewall that include FreeS/WAN configuration management.</LI>
+<LI><A href="http://www.linuxwall.de">Linuxwall</A></LI>
+<LI><A href="http://www.smoothwall.org/">Smoothwall</A></LI>
+<LI><A href="http://www.devil-linux.org/">Devil Linux</A></LI>
+<LI>Coyote Linux has a<A href="http://embedded.coyotelinux.com/wolverine/index.php">
+ Wolverine</A> firewall/VPN server</LI>
+</UL>
+<P>There are also several sets of scripts available for managing a
+ firewall which is also acting as a FreeS/WAN IPsec gateway. See this<A href="firewall.html#rules.pub">
+ list</A>.</P>
+<H3><A name="turnkey">Firewall and VPN products</A></H3>
+<P>Several vendors use FreeS/WAN as the IPsec component of a turnkey
+ firewall or VPN product.</P>
+<P>Software-only products:</P>
+<UL>
+<LI><A href="http://www.linuxmagic.com/vpn/index.html">Linux Magic</A>
+ offer a VPN/Firewall product using FreeS/WAN</LI>
+<LI>The Software Group's<A href="http://www.wanware.com/sentinet/">
+ Sentinet</A> product uses FreeS/WAN</LI>
+<LI><A href="http://www.merilus.com">Merilus</A> use FreeS/WAN in their
+ Gateway Guardian firewall product</LI>
+</UL>
+<P>Products that include the hardware:</P>
+<UL>
+<LI>The<A href="http://www.lasat.com"> LASAT SafePipe[tm]</A> series. is
+ an IPsec box based on an embedded MIPS running Linux with FreeS/WAN and
+ a web-config front end. This company also host our freeswan.org web
+ site.</LI>
+<LI>Merilus<A href="http://www.merilus.com/products/fc/index.shtml">
+ Firecard</A> is a Linux firewall on a PCI card.</LI>
+<LI><A href="http://www.kyzo.com/">Kyzo</A> have a &quot;pizza box&quot; product
+ line with various types of server, all running from flash. One of them
+ is an IPsec/PPTP VPN server</LI>
+<LI><A href="http://www.pfn.com">PFN</A> use FreeS/WAN in some of their
+ products</LI>
+</UL>
+<P><A href="www.rebel.com">Rebel.com</A>, makers of the Netwinder Linux
+ machines (ARM or Crusoe based), had a product that used FreeS/WAN. The
+ company is in receivership so the future of the Netwinder is at best
+ unclear.<A href="web.html#patch"> PKIX patches</A> for FreeS/WAN
+ developed at Rebel are listed in our web links document.</P>
+<H2><A name="docs">Information sources</A></H2>
+<H3><A name="docformats">This HowTo, in multiple formats</A></H3>
+<P>FreeS/WAN documentation up to version 1.5 was available only in HTML.
+ Now we ship two formats:</P>
+<UL>
+<LI>as HTML, one file for each doc section plus a global<A href="toc.html">
+ Table of Contents</A></LI>
+<LI><A href="HowTo.html">one big HTML file</A> for easy searching</LI>
+</UL>
+<P>and provide a Makefile to generate other formats if required:</P>
+<UL>
+<LI><A href="HowTo.pdf">PDF</A></LI>
+<LI><A href="HowTo.ps">Postscript</A></LI>
+<LI><A href="HowTo.txt">ASCII text</A></LI>
+</UL>
+<P>The Makefile assumes the htmldoc tool is available. You can download
+ it from<A href="http://www.easysw.com"> Easy Software</A>.</P>
+<P>All formats should be available at the following websites:</P>
+<UL>
+<LI><A href="http://www.freeswan.org/doc.html">FreeS/WAN project</A></LI>
+<LI><A href="http://www.linuxdoc.org">Linux Documentation Project</A></LI>
+</UL>
+<P>The distribution tarball has only the two HTML formats.</P>
+<P><STRONG>Note:</STRONG> If you need the latest doc version, for
+ example to see if anyone has managed to set up interoperation between
+ FreeS/WAN and whatever, then you should download the current snapshot.
+ What is on the web is documentation as of the last release. Snapshots
+ have all changes I've checked in to date.</P>
+<H3><A name="rtfm">RTFM (please Read The Fine Manuals)</A></H3>
+<P>As with most things on any Unix-like system, most parts of Linux
+ FreeS/WAN are documented in online manual pages. We provide a list of<A href="/mnt/floppy/manpages.html">
+ FreeS/WAN man pages</A>, with links to HTML versions of them.</P>
+<P>The man pages describing configuration files are:</P>
+<UL>
+<LI><A href="/mnt/floppy/manpage.d/ipsec.conf.5.html">ipsec.conf(5)</A></LI>
+<LI><A href="/mnt/floppy/manpage.d/ipsec.secrets.5.html">
+ipsec.secrets(5)</A></LI>
+</UL>
+<P>Man pages for common commands include:</P>
+<UL>
+<LI><A href="/mnt/floppy/manpage.d/ipsec.8.html">ipsec(8)</A></LI>
+<LI><A href="/mnt/floppy/manpage.d/ipsec_pluto.8.html">ipsec_pluto(8)</A>
+</LI>
+<LI><A href="/mnt/floppy/manpage.d/ipsec_newhostkey.8.html">
+ipsec_newhostkey(8)</A></LI>
+<LI><A href="/mnt/floppy/manpage.d/ipsec_auto.8.html">ipsec_auto(8)</A></LI>
+</UL>
+<P>You can read these either in HTML using the links above or with the<VAR>
+ man(1)</VAR> command.</P>
+<P>In the event of disagreement between this HTML documentation and the
+ man pages, the man pages are more likely correct since they are written
+ by the implementers. Please report any such inconsistency on the<A href="mail.html#lists">
+ mailing list</A>.</P>
+<H3><A name="text">Other documents in the distribution</A></H3>
+<P>Text files in the main distribution directory are README, INSTALL,
+ CREDITS, CHANGES, BUGS and COPYING.</P>
+<P>The Libdes encryption library we use has its own documentation. You
+ can find it in the library directory..</P>
+<H3><A name="assumptions">Background material</A></H3>
+<P>Throughout this documentation, I write as if the reader had at least
+ a general familiarity with Linux, with Internet Protocol networking,
+ and with the basic ideas of system and network security. Of course that
+ will certainly not be true for all readers, and quite likely not even
+ for a majority.</P>
+<P>However, I must limit amount of detail on these topics in the main
+ text. For one thing, I don't understand all the details of those topics
+ myself. Even if I did, trying to explain everything here would produce
+ extremely long and almost completely unreadable documentation.</P>
+<P>If one or more of those areas is unknown territory for you, there are
+ plenty of other resources you could look at:</P>
+<DL>
+<DT>Linux</DT>
+<DD>the<A href="http://www.linuxdoc.org"> Linux Documentation Project</A>
+ or a local<A href="http://www.linux.org/groups/"> Linux User Group</A>
+ and these<A href="web.html#linux.link"> links</A></DD>
+<DT>IP networks</DT>
+<DD>Rusty Russell's<A href="http://netfilter.samba.org/unreliable-guides/networking-concepts-HOWTO/index.html">
+ Networking Concepts HowTo</A> and these<A href="web.html#IP.background">
+ links</A></DD>
+<DT>Security</DT>
+<DD>Schneier's book<A href="biblio.html#secrets"> Secrets and Lies</A>
+ and these<A href="web.html#crypto.link"> links</A></DD>
+</DL>
+<P>Also, I do make an effort to provide some background material in
+ these documents. All the basic ideas behind IPsec and FreeS/WAN are
+ explained here. Explanations that do not fit in the main text, or that
+ not everyone will need, are often in the<A href="glossary.html#ourgloss">
+ glossary</A>, which is the largest single file in this document set.
+ There is also a<A href="background.html#background"> background</A>
+ file containing various explanations too long to fit in glossary
+ definitions. All files are heavily sprinkled with links to each other
+ and to the glossary.<STRONG> If some passage makes no sense to you, try
+ the links</STRONG>.</P>
+<P>For other reference material, see the<A href="biblio.html#biblio">
+ bibliography</A> and our collection of<A href="web.html#weblinks"> web
+ links</A>.</P>
+<P>Of course, no doubt I get this (and other things) wrong sometimes.
+ Feedback via the<A href="mail.html#lists"> mailing lists</A> is
+ welcome.</P>
+<H3><A name="archives">Archives of the project mailing list</A></H3>
+<P>Until quite recently, there was only one FreeS/WAN mailing list, and
+ archives of it were:</P>
+<UL>
+<LI><A href="http://www.sandelman.ottawa.on.ca/linux-ipsec">Canada</A></LI>
+<LI><A href="http://www.nexial.com">Holland</A></LI>
+</UL>
+ The two archives use completely different search engines. You might
+ want to try both.
+<P>More recently we have expanded to five lists, each with its own
+ archive.</P>
+<P><A href="mail.html#lists">More information</A> on mailing lists.</P>
+<H3><A name="howto">User-written HowTo information</A></H3>
+<P>Various user-written HowTo documents are available. The ones covering
+ FreeS/WAN-to-FreeS/WAN connections are:</P>
+<UL>
+<LI>Jean-Francois Nadeau's<A href="http://jixen.tripod.com/"> practical
+ configurations</A> document</LI>
+<LI>Jens Zerbst's HowTo on<A href="http://dynipsec.tripod.com/"> Using
+ FreeS/WAN with dynamic IP addresses</A>.</LI>
+<LI>an entry in Kurt Seifried's<A href="http://www.securityportal.com/lskb/kben00000013.html">
+ Linux Security Knowledge Base</A>.</LI>
+<LI>a section of David Ranch's<A href="http://www.ecst.csuchico.edu/~dranch/LINUX/index-linux.html#trinityos">
+ Trinity OS Guide</A></LI>
+<LI>a section in David Bander's book<A href="biblio.html#bander"> Linux
+ Security Toolkit</A></LI>
+</UL>
+<P>User-wriiten HowTo material may be<STRONG> especially helpful if you
+ need to interoperate with another IPsec implementation</STRONG>. We
+ have neither the equipment nor the manpower to test such
+ configurations. Users seem to be doing an admirable job of filling the
+ gaps.</P>
+<UL>
+<LI>list of user-written<A href="interop.html#otherpub"> interoperation
+ HowTos</A> in our interop document</LI>
+</UL>
+<P>Check what version of FreeS/WAN user-written documents cover. The
+ software is under active development and the current version may be
+ significantly different from what an older document describes.</P>
+<H3><A name="applied">Papers on FreeS/WAN</A></H3>
+<P>Two design documents show team thinking on new developments:</P>
+<UL>
+<LI><A href="opportunism.spec">Opportunistic Encryption</A> by technical
+ lead Henry Spencer and Pluto programmer Hugh Redelemeier</LI>
+<LI>discussion of<A href="http://www.sandelman.ottawa.on.ca/SSW/freeswan/klips2req/">
+ KLIPS redesign</A></LI>
+</UL>
+<P>Both documents are works in progress and are frequently revised. For
+ the latest version, see the<A href="mail.html#lists"> design mailing
+ list</A>. Comments should go to that list.</P>
+<P>There is now an<A href="http://www.ietf.org/internet-drafts/draft-richardson-ipsec-opportunistic-06.txt">
+ Internet Draft on Opportunistic Encryption</A> by Michael Richardson,
+ Hugh Redelmeier and Henry Spencer. This is a first step toward getting
+ the protocol standardised so there can be multiple implementations of
+ it. Discussion of it takes place on the<A href="http://www.ietf.org/html.charters/ipsec-charter.html">
+ IETF IPsec Working Group</A> mailing list.</P>
+<P>A number of papers giving further background on FreeS/WAN, or
+ exploring its future or its applications, are also available:</P>
+<UL>
+<LI>Both Henry and Richard gave talks on FreeS/WAN at the 2000<A href="http://www.linuxsymposium.org">
+ Ottawa Linux Symposium</A>.
+<UL>
+<LI>Richard's<A href="http://www.conscoop.ottawa.on.ca/rgb/freeswan/ols2k/">
+ slides</A></LI>
+<LI>Henry's paper</LI>
+<LI>MP3 audio of their talks is available from the<A href="http://www.linuxsymposium.org/">
+ conference page</A></LI>
+</UL>
+</LI>
+<LI><CITE>Moat: A Virtual Private Network Appliances and Services
+ Platform</CITE> is a paper about large-scale (a few 100 links) use of
+ FreeS/WAN in a production application at AT&amp;T Research. It is available
+ in Postscript or PDF from co-author Steve Bellovin's<A href="http://www.research.att.com/~smb/papers/index.html">
+ papers list page</A>.</LI>
+<LI>One of the Moat co-authors, John Denker, has also written
+<UL>
+<LI>a<A href="http://www.av8n.com/vpn/ipsec+routing.htm"> proposal</A>
+ for how future versions of FreeS/WAN might interact with routing
+ protocols</LI>
+<LI>a<A href="http://www.av8n.com/vpn/wishlist.htm"> wishlist</A> of
+ possible new features</LI>
+</UL>
+</LI>
+<LI>Bart Trojanowski's web page has a draft design for<A href="http://www.jukie.net/~bart/linux-ipsec/">
+ hardware acceleration</A> of FreeS/WAN</LI>
+</UL>
+<P>Several of these provoked interesting discussions on the mailing
+ lists, worth searching for in the<A href="mail.html#archive"> archives</A>
+.</P>
+<P>There are also several papers in languages other than English, see
+ our<A href="web.html#otherlang"> web links</A>.</P>
+<H3><A name="licensing">License and copyright information</A></H3>
+<P>All code and documentation written for this project is distributed
+ under either the GNU General Public License (<A href="glossary.html#GPL">
+GPL</A>) or the GNU Library General Public License. For details see the
+ COPYING file in the distribution.</P>
+<P>Not all code in the distribution is ours, however. See the CREDITS
+ file for details. In particular, note that the<A href="glossary.html#LIBDES">
+ Libdes</A> library and the version of<A href="glossary.html#MD5"> MD5</A>
+ that we use each have their own license.</P>
+<H2><A name="sites">Distribution sites</A></H2>
+<P>FreeS/WAN is available from a number of sites.</P>
+<H3><A NAME="1_5_1">Primary site</A></H3>
+<P>Our primary site, is at xs4all (Thanks, folks!) in Holland:</P>
+<UL>
+<LI><A href="http://www.xs4all.nl/~freeswan">HTTP</A></LI>
+<LI><A href="ftp://ftp.xs4all.nl/pub/crypto/freeswan">FTP</A></LI>
+</UL>
+<H3><A name="mirrors">Mirrors</A></H3>
+<P>There are also mirror sites all over the world:</P>
+<UL>
+<LI><A href="http://www.flora.org/freeswan">Eastern Canada</A> (limited
+ resouces)</LI>
+<LI><A href="ftp://ludwig.doculink.com/pub/freeswan/">Eastern Canada</A>
+ (has older versions too)</LI>
+<LI><A href="ftp://ntsc.notBSD.org/pub/crypto/freeswan/">Eastern Canada</A>
+ (has older versions too)</LI>
+<LI><A href="ftp://ftp.kame.net/pub/freeswan/">Japan</A></LI>
+<LI><A href="ftp://ftp.futuredynamics.com/freecrypto/FreeSWAN/">Hong
+ Kong</A></LI>
+<LI><A href="ftp://ipsec.dk/pub/freeswan/">Denmark</A></LI>
+<LI><A href="ftp://ftp.net.lut.ac.uk/freeswan">the UK</A></LI>
+<LI><A href="http://storm.alert.sk/comp/mirrors/freeswan/">Slovak
+ Republic</A></LI>
+<LI><A href="http://the.wiretapped.net/security/vpn-tunnelling/freeswan/">
+Australia</A></LI>
+<LI><A href="http://freeswan.technolust.cx/">technolust</A></LI>
+<LI><A href="http://freeswan.devguide.de/">Germany</A></LI>
+<LI>Ivan Moore's<A href="http://snowcrash.tdyc.com/freeswan/"> site</A></LI>
+<LI>the<A href="http://www.cryptoarchive.net/"> Crypto Archive</A> on
+ the<A href="http://www.securityportal.com/"> Security Portal</A> site</LI>
+<LI><A href="http://www.wiretapped.net/">Wiretapped.net</A> in Australia</LI>
+</UL>
+<P>Thanks to those folks as well.</P>
+<H3><A name="munitions">The &quot;munitions&quot; archive of Linux crypto software</A>
+</H3>
+<P>There is also an archive of Linux crypto software called &quot;munitions&quot;,
+ with its own mirrors in a number of countries. It includes FreeS/WAN,
+ though not always the latest version. Some of its sites are:</P>
+<UL>
+<LI><A href="http://munitions.vipul.net/">Germany</A></LI>
+<LI><A href="http://munitions.iglu.cjb.net/">Italy</A></LI>
+<LI><A href="http://munitions2.xs4all.nl/">Netherlands</A></LI>
+</UL>
+<P>Any of those will have a list of other &quot;munitions&quot; mirrors. There is
+ also a CD available.</P>
+<H2><A NAME="1_6">Links to other sections</A></H2>
+<P>For more detailed background information, see:</P>
+<UL>
+<LI><A href="politics.html#politics">history and politics</A> of
+ cryptography</LI>
+<LI><A href="ipsec.html#ipsec.detail">IPsec protocols</A></LI>
+</UL>
+<P>To begin working with FreeS/WAN, go to our<A href="quickstart.html#quick.guide">
+ quickstart</A> guide.</P>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="upgrading.html">Next</A>
+</BODY>
+</HTML>
diff --git a/doc/ipsec.conf.2_to_1 b/doc/ipsec.conf.2_to_1
new file mode 100644
index 000000000..3100ed78d
--- /dev/null
+++ b/doc/ipsec.conf.2_to_1
@@ -0,0 +1,22 @@
+version 2
+# If you put the preceding line in front of a 1.x ipsec.conf, 
+# it should work within 2.x.
+
+
+# Merge the following sections with your existing config setup
+# and conn %default.
+# Allot these values to any you have not explictly defined.
+
+config setup
+        interfaces=%none     # new default is %defaultroute
+        plutoload=%none     # new default is %search
+        plutostart=%none     # new default is %search
+
+conn %default
+        uniqueids=no     # new default is yes
+        keyingtries=3     # new default is %forever
+        disablearrivalcheck=yes     # new default is no
+        authby=secret     # new default is rsasig
+        leftrsasigkey=%none     # new default %dnsondemand
+        rightrsasigkey=%none     # new default %dnsondemand
+
diff --git a/doc/ipsec.html b/doc/ipsec.html
new file mode 100644
index 000000000..4fb27b92b
--- /dev/null
+++ b/doc/ipsec.html
@@ -0,0 +1,1040 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
+H5 { font-family: sans-serif }
+H6 { font-family: sans-serif }
+SUB { font-size: smaller }
+SUP { font-size: smaller }
+PRE { font-family: monospace }
+--></STYLE>
+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="politics.html">Previous</A>
+<A HREF="mail.html">Next</A>
+<HR>
+<H1><A name="ipsec.detail">The IPsec protocols</A></H1>
+<P>This section provides information on the IPsec protocols which
+ FreeS/WAN implements. For more detail, see the<A href="rfc.html"> RFCs</A>
+.</P>
+<P>The basic idea of IPsec is to provide security functions,<A href="glossary.html#authentication">
+ authentication</A> and<A href="glossary.html#encryption"> encryption</A>
+, at the IP (Internet Protocol) level. This requires a higher-level
+ protocol (IKE) to set things up for the IP-level services (ESP and AH).</P>
+<H2><A NAME="27_1">Protocols and phases</A></H2>
+<P>Three protocols are used in an IPsec implementation:</P>
+<DL>
+<DT>ESP, Encapsulating Security Payload</DT>
+<DD>Encrypts and/or authenticates data</DD>
+<DT>AH, Authentication Header</DT>
+<DD>Provides a packet authentication service</DD>
+<DT>IKE, Internet Key Exchange</DT>
+<DD>Negotiates connection parameters, including keys, for the other two</DD>
+</DL>
+<P>The term &quot;IPsec&quot; (also written as IPSEC) is slightly ambiguous. In
+ some contexts, it includes all three of the above but in other contexts
+ it refers only to AH and ESP.</P>
+<P>There is more detail below, but a quick summary of how the whole
+ thing works is:</P>
+<DL>
+<DT>Phase one IKE (main mode exchange)</DT>
+<DD>sets up a keying channel (ISAKMP SA) between the two gateways</DD>
+<DT>Phase two IKE (quick mode exchange)</DT>
+<DD>sets up data channels (IPsec SAs)</DD>
+<DT>IPsec proper</DT>
+<DD>exchanges data using AH or ESP</DD>
+</DL>
+<P>Both phases of IKE are repeated periodically to automate re-keying.</P>
+<H2><A name="others">Applying IPsec</A></H2>
+<P>Authentication and encryption functions for network data can, of
+ course, be provided at other levels. Many security protocols work at
+ levels above IP.</P>
+<UL>
+<LI><A href="glossary.html#PGP">PGP</A> encrypts and authenticates mail
+ messages</LI>
+<LI><A href="glossary.html#SSH">SSH</A> authenticates remote logins and
+ then encrypts the session</LI>
+<LI><A href="glossary.html#SSL">SSL</A> or<A href="glossary.html#TLS">
+ TLS</A> provides security at the sockets layer, e.g. for secure web
+ browsing</LI>
+</UL>
+<P>and so on. Other techniques work at levels below IP. For example,
+ data on a communications circuit or an entire network can be encrypted
+ by specialised hardware. This is common practice in high-security
+ applications.</P>
+<H3><A name="advantages">Advantages of IPsec</A></H3>
+<P>There are, however, advantages to doing it at the IP level instead
+ of, or as well as, at other levels.</P>
+<P>IPsec is the<STRONG> most general way to provide these services for
+ the Internet</STRONG>.</P>
+<UL>
+<LI>Higher-level services protect a<EM> single protocol</EM>; for
+ example PGP protects mail.</LI>
+<LI>Lower level services protect a<EM> single medium</EM>; for example a
+ pair of encryption boxes on the ends of a line make wiretaps on that
+ line useless unless the attacker is capable of breaking the encryption.</LI>
+</UL>
+<P>IPsec, however, can protect<EM> any protocol</EM> running above IP
+ and<EM> any medium</EM> which IP runs over. More to the point, it can
+ protect a mixture of application protocols running over a complex
+ combination of media. This is the normal situation for Internet
+ communication; IPsec is the only general solution.</P>
+<P>IPsec can also provide some security services &quot;in the background&quot;,
+ with<STRONG> no visible impact on users</STRONG>. To use<A href="glossary.html#PGP">
+ PGP</A> encryption and signatures on mail, for example, the user must
+ at least:</P>
+<UL>
+<LI>remember his or her passphrase,</LI>
+<LI>keep it secure</LI>
+<LI>follow procedures to validate correspondents' keys</LI>
+</UL>
+<P>These systems can be designed so that the burden on users is not
+ onerous, but any system will place some requirements on users. No such
+ system can hope to be secure if users are sloppy about meeting those
+ requirements. The author has seen username and password stuck on
+ terminals with post-it notes in an allegedly secure environment, for
+ example.</P>
+<H3><A name="limitations">Limitations of IPsec</A></H3>
+<P>IPsec is designed to secure IP links between machines. It does that
+ well, but it is important to remember that there are many things it
+ does not do. Some of the important limitations are:</P>
+<DL>
+<DT><A name="depends">IPsec cannot be secure if your system isn't</A></DT>
+<DD>System security on IPsec gateway machines is an essential
+ requirement if IPsec is to function as designed. No system can be
+ trusted if the underlying machine has been subverted. See books on Unix
+ security such as<A href="biblio.html#practical"> Garfinkel and Spafford</A>
+ or our web references for<A href="web.html#linsec"> Linux security</A>
+ or more general<A href="web.html#compsec"> computer security</A>.
+<P>Of course, there is another side to this. IPsec can be a powerful
+ tool for improving system and network security. For example, requiring
+ packet authentication makes various spoofing attacks harder and IPsec
+ tunnels can be extremely useful for secure remote administration of
+ various things.</P>
+</DD>
+<DT><A name="not-end-to-end">IPsec is not end-to-end</A></DT>
+<DD>IPsec cannot provide the same end-to-end security as systems working
+ at higher levels. IPsec encrypts an IP connection between two machines,
+ which is quite a different thing than encrypting messages between users
+ or between applications.
+<P>For example, if you need mail encrypted from the sender's desktop to
+ the recipient's desktop and decryptable only by the recipient, use<A href="glossary.html#PGP">
+ PGP</A> or another such system. IPsec can encrypt any or all of the
+ links involved -- between the two mail servers, or between either
+ server and its clients. It could even be used to secure a direct IP
+ link from the sender's desktop machine to the recipient's, cutting out
+ any sort of network snoop. What it cannot ensure is end-to-end
+ user-to-user security. If only IPsec is used to secure mail, then
+ anyone with appropriate privileges on any machine where that mail is
+ stored (at either end or on any store-and-forward servers in the path)
+ can read it.</P>
+<P>In another common setup, IPsec encrypts packets at a security gateway
+ machine as they leave the sender's site and decrypts them on arrival at
+ the gateway to the recipient's site. This does provide a useful
+ security service -- only encrypted data is passed over the Internet --
+ but it does not even come close to providing an end-to-end service. In
+ particular, anyone with appropriate privileges on either site's LAN can
+ intercept the message in unencrypted form.</P>
+</DD>
+<DT><A name="notpanacea">IPsec cannot do everything</A></DT>
+<DD>IPsec also cannot provide all the functions of systems working at
+ higher levels of the protocol stack. If you need a document
+ electronically signed by a particular person, then you need his or her<A
+href="glossary.html#signature"> digital signature</A> and a<A href="glossary.html#public">
+ public key cryptosystem</A> to verify it with.
+<P>Note, however, that IPsec authentication of the underlying
+ communication can make various attacks on higher-level protocols more
+ difficult. In particular, authentication prevents<A href="glossary.html#middle">
+ man-in-the-middle attacks</A>.</P>
+</DD>
+<DT><A name="no_user">IPsec authenticates machines, not users</A></DT>
+<DD>IPsec uses strong authentication mechanisms to control which
+ messages go to which machines, but it does not have the concept of user
+ ID, which is vital to many other security mechansims and policies. This
+ means some care must be taken in fitting the various security
+ mechansims on a network together. For example, if you need to control
+ which users access your database server, you need some non-IPsec
+ mechansim for that. IPsec can control which machines connect to the
+ server, and can ensure that data transfer to those machines is done
+ securely, but that is all. Either the machines themselves must control
+ user access or there must be some form of user authentication to the
+ database, independent of IPsec.</DD>
+<DT><A name="DoS">IPsec does not stop denial of service attacks</A></DT>
+<DD><A href="glossary.html#DOS">Denial of service</A> attacks aim at
+ causing a system to crash, overload, or become confused so that
+ legitimate users cannot get whatever services the system is supposed to
+ provide. These are quite different from attacks in which the attacker
+ seeks either to use the service himself or to subvert the service into
+ delivering incorrect results.
+<P>IPsec shifts the ground for DoS attacks; the attacks possible against
+ systems using IPsec are different than those that might be used against
+ other systems. It does not, however, eliminate the possibility of such
+ attacks.</P>
+</DD>
+<DT><A name="traffic">IPsec does not stop traffic analysis</A></DT>
+<DD><A href="glossary.html#traffic">Traffic analysis</A> is the attempt
+ to derive intelligence from messages without regard for their contents.
+ In the case of IPsec, it would mean analysis based on things visible in
+ the unencrypted headers of encrypted packets -- source and destination
+ gateway addresses, packet size, et cetera. Given the resources to
+ acquire such data and some skill in analysing it (both of which any
+ national intelligence agency should have), this can be a very powerful
+ technique.
+<P>IPsec is not designed to defend against this. Partial defenses are
+ certainly possible, and some are<A href="#traffic.resist"> described
+ below</A>, but it is not clear that any complete defense can be
+ provided.</P>
+</DD>
+</DL>
+<H3><A name="uses">IPsec is a general mechanism for securing IP</A></H3>
+<P>While IPsec does not provide all functions of a mail encryption
+ package, it can encrypt your mail. In particular, it can ensure that
+ all mail passing between a pair or a group of sites is encrypted. An
+ attacker looking only at external traffic, without access to anything
+ on or behind the IPsec gateway, cannot read your mail. He or she is
+ stymied by IPsec just as he or she would be by<A href="glossary.html#PGP">
+ PGP</A>.</P>
+<P>The advantage is that IPsec can provide the same protection for<STRONG>
+ anything transmitted over IP</STRONG>. In a corporate network example,
+ PGP lets the branch offices exchange secure mail with head office. SSL
+ and SSH allow them to securely view web pages, connect as terminals to
+ machines, and so on. IPsec can support all those applications, plus
+ database queries, file sharing (NFS or Windows), other protocols
+ encapsulated in IP (Netware, Appletalk, ...), phone-over-IP,
+ video-over-IP, ... anything-over-IP. The only limitation is that IP
+ Multicast is not yet supported, though there are Internet Draft
+ documents for that.</P>
+<P>IPsec creates<STRONG> secure tunnels through untrusted networks</STRONG>
+. Sites connected by these tunnels form VPNs,<A href="glossary.html#VPN">
+ Virtual Private Networks</A>.</P>
+<P>IPsec gateways can be installed wherever they are required.</P>
+<UL>
+<LI>One organisation might choose to install IPsec only on firewalls
+ between their LANs and the Internet. This would allow them to create a
+ VPN linking several offices. It would provide protection against anyone
+ outside their sites.</LI>
+<LI>Another might install IPsec on departmental servers so everything on
+ the corporate backbone net was encrypted. This would protect messages
+ on that net from everyone except the sending and receiving department.</LI>
+<LI>Another might be less concerned with information secrecy and more
+ with controlling access to certain resources. They might use IPsec
+ packet authentication as part of an access control mechanism, with or
+ without also using the IPsec encryption service.</LI>
+<LI>It is even possible (assuming adequate processing power and an IPsec
+ implementation in each node) to make every machine its own IPsec
+ gateway so that everything on a LAN is encrypted. This protects
+ information from everyone outside the sending and receiving machine.</LI>
+<LI>These techniques can be combined in various ways. One might, for
+ example, require authentication everywhere on a network while using
+ encryption only for a few links.</LI>
+</UL>
+<P>Which of these, or of the many other possible variants, to use is up
+ to you.<STRONG> IPsec provides mechanisms; you provide the policy</STRONG>
+.</P>
+<P><STRONG>No end user action is required</STRONG> for IPsec security to
+ be used; they don't even have to know about it. The site
+ administrators, of course, do have to know about it and to put some
+ effort into making it work. Poor administration can compromise IPsec as
+ badly as the post-it notes mentioned above. It seems reasonable,
+ though, for organisations to hope their system administrators are
+ generally both more security-conscious than end users and more able to
+ follow computer security procedures. If not, at least there are fewer
+ of them to educate or replace.</P>
+<P>IPsec can be, and often should be, used with along with security
+ protocols at other levels. If two sites communicate with each other via
+ the Internet, then IPsec is the obvious way to protect that
+ communication. If two others have a direct link between them, either
+ link encryption or IPsec would make sense. Choose one or use both.
+ Whatever you use at and below the IP level, use other things as
+ required above that level. Whatever you use above the IP level,
+ consider what can be done with IPsec to make attacks on the higher
+ levels harder. For example,<A href="glossary.html#middle">
+ man-in-the-middle attacks</A> on various protocols become difficult if
+ authentication at packet level is in use on the potential victims'
+ communication channel.</P>
+<H3><A name="authonly">Using authentication without encryption</A></H3>
+<P>Where appropriate, IPsec can provide authentication without
+ encryption. One might do this, for example:</P>
+<UL>
+<LI>where the data is public but one wants to be sure of getting the
+ right data, for example on some web sites</LI>
+<LI>where encryption is judged unnecessary, for example on some company
+ or department LANs</LI>
+<LI>where strong encryption is provided at link level, below IP</LI>
+<LI>where strong encryption is provided in other protocols, above IP
+<BR> Note that IPsec authentication may make some attacks on those
+ protocols harder.</LI>
+</UL>
+<P>Authentication has lower overheads than encryption.</P>
+<P>The protocols provide four ways to build such connections, using
+ either an AH-only connection or ESP using null encryption, and in
+ either manually or automatically keyed mode. FreeS/WAN supports only
+ one of these, manually keyed AH-only connections, and<STRONG> we do not
+ recommend using that</STRONG>. Our reasons are discussed under<A href="#traffic.resist">
+ Resisting traffic analysis</A> a few sections further along.</P>
+<H3><A name="encnoauth">Encryption without authentication is dangerous</A>
+</H3>
+<P>Originally, the IPsec encryption protocol<A href="glossary.html#ESP">
+ ESP</A> didn't do integrity checking. It only did encryption. Steve
+ Bellovin found many ways to attack ESP used without authentication. See
+ his paper<A href="http://www.research.att.com/~smb/papers/badesp.ps">
+ Problem areas for the IP Security Protocols</A>. To make a secure
+ connection, you had to add an<A href="glossary.html#AH"> AH</A>
+ Authentication Header as well as ESP. Rather than incur the overhead of
+ several layers (and rather than provide an ESP layer that didn't
+ actually protect the traffic), the IPsec working group built integrity
+ and replay checking directly into ESP.</P>
+<P>Today, typical usage is one of:</P>
+<UL>
+<LI>ESP for encryption and authentication</LI>
+<LI>AH for authentication alone</LI>
+</UL>
+<P>Other variants are allowed by the standard, but not much used:</P>
+<DL>
+<DT>ESP encryption without authentication</DT>
+<DD><STRONG>Bellovin has demonstrated fatal flaws in this. Do not use.</STRONG>
+</DD>
+<DT>ESP encryption with AH authentication</DT>
+<DD>This has higher overheads than using the authentication in ESP, and
+ no obvious benefit in most cases. The exception might be a network
+ where AH authentication was widely or universally used. If you're going
+ to do AH to conform with network policy, why authenticate again in the
+ ESP layer?</DD>
+<DT>Authenticate twice, with AH and with ESP</DT>
+<DD>Why? Of course, some folk consider &quot;belt and suspenders&quot; the
+ sensible approach to security. If you're among them, you might use both
+ protocols here. You might also use both to satisfy different parts of a
+ security policy. For example, an organisation might require AH
+ authentication everywhere but two users within the organisation might
+ use ESP as well.</DD>
+<DT>ESP authentication without encryption</DT>
+<DD>The standard allows this, calling it &quot;null encryption&quot;. FreeS/WAN
+ does not support it. We recommend that you use AH instead if
+ authentication is all you require. AH authenticates parts of the IP
+ header, which ESP-null does not do.</DD>
+</DL>
+<P>Some of these variants cannot be used with FreeS/WAN because we do
+ not support ESP-null and do not support automatic keying of AH-only
+ connections.</P>
+<P>There are fairly frequent suggestions that AH be dropped entirely
+ from the IPsec specifications since ESP and null encryption can handle
+ that situation. It is not clear whether this will occur. My guess is
+ that it is unlikely.</P>
+<H3><A name="multilayer">Multiple layers of IPsec processing are
+ possible</A></H3>
+<P>The above describes combinations possible on a single IPsec
+ connection. In a complex network you may have several layers of IPsec
+ in play, with any of the above combinations at each layer.</P>
+<P>For example, a connection from a desktop machine to a database server
+ might require AH authentication. Working with other host, network and
+ database security measures, AH might be just the thing for access
+ control. You might decide not to use ESP encryption on such packets,
+ since it uses resources and might complicate network debugging. Within
+ the site where the server is, then, only AH would be used on those
+ packets.</P>
+<P>Users at another office, however, might have their whole connection
+ (AH headers and all) passing over an IPsec tunnel connecting their
+ office to the one with the database server. Such a tunnel should use
+ ESP encryption and authentication. You need authentication in this
+ layer because without authentication the encryption is vulnerable and
+ the gateway cannot verify the AH authentication. The AH is between
+ client and database server; the gateways aren't party to it.</P>
+<P>In this situation, some packets would get multiple layers of IPsec
+ applied to them, AH on an end-to-end client-to-server basis and ESP
+ from one office's security gateway to the other.</P>
+<H3><A name="traffic.resist">Resisting traffic analysis</A></H3>
+<P><A href="glossary.html#traffic">Traffic analysis</A> is the attempt
+ to derive useful intelligence from encrypted traffic without breaking
+ the encryption.</P>
+<P>Is your CEO exchanging email with a venture capital firm? With
+ bankruptcy trustees? With an executive recruiting agency? With the
+ holder of some important patents? If an eavesdropper learns about any
+ of those, then he has interesting intelligence on your company, whether
+ or not he can read the messages themselves.</P>
+<P>Even just knowing that there is network traffic between two sites may
+ tell an analyst something useful, especially when combined with
+ whatever other information he or she may have. For example, if you know
+ Company A is having cashflow problems and Company B is looking for
+ aquisitions, then knowing that packets are passing between the two is
+ interesting. It is more interesting if you can tell it is email, and
+ perhaps yet more if you know the sender and recipient.</P>
+<P>Except in the simplest cases, traffic analysis is hard to do well. It
+ requires both considerable resources and considerable analytic skill.
+ However, intelligence agencies of various nations have been doing it
+ for centuries and many of them are likely quite good at it by now.
+ Various commercial organisations, especially those working on &quot;targeted
+ marketing&quot; may also be quite good at analysing certain types of
+ traffic.</P>
+<P>In general, defending against traffic analysis is also difficult.
+ Inventing a really good defense could get you a PhD and some
+ interesting job offers.</P>
+<P>IPsec is not designed to stop traffic analysis and we know of no
+ plausible method of extending it to do so. That said, there are ways to
+ make traffic analysis harder. This section describes them.</P>
+<H4><A name="extra">Using &quot;unnecessary&quot; encryption</A></H4>
+<P>One might choose to use encryption even where it appears unnecessary
+ in order to make analysis more difficult. Consider two offices which
+ pass a small volume of business data between them using IPsec and also
+ transfer large volumes of Usenet news. At first glance, it would seem
+ silly to encrypt the newsfeed, except possibly for any newsgroups that
+ are internal to the company. Why encrypt data that is all publicly
+ available from many sites?</P>
+<P>However, if we encrypt a lot of news and send it down the same
+ connection as our business data, we make<A href="glossary.html#traffic">
+ traffic analysis</A> much harder. A snoop cannot now make inferences
+ based on patterns in the volume, direction, sizes, sender, destination,
+ or timing of our business messages. Those messages are hidden in a mass
+ of news messages encapsulated in the same way.</P>
+<P>If we're going to do this we need to ensure that keys change often
+ enough to remain secure even with high volumes and with the adversary
+ able to get plaintext of much of the data. We also need to look at
+ other attacks this might open up. For example, can the adversary use a
+ chosen plaintext attack, deliberately posting news articles which, when
+ we receive and encrypt them, will help break our encryption? Or can he
+ block our business data transmission by flooding us with silly news
+ articles? Or ...</P>
+<P>Also, note that this does not provide complete protection against
+ traffic analysis. A clever adversary might still deduce useful
+ intelligence from statistical analysis (perhaps comparing the input
+ newsfeed to encrypted output, or comparing the streams we send to
+ different branch offices), or by looking for small packets which might
+ indicate establishment of TCP connections, or ...</P>
+<P>As a general rule, though, to improve resistance to traffic analysis,
+ you should<STRONG> encrypt as much traffic as possible, not just as
+ much as seems necessary.</STRONG></P>
+<H4><A name="multi-encrypt">Using multiple encryption</A></H4>
+<P>This also applies to using multiple layers of encryption. If you have
+ an IPsec tunnel between two branch offices, it might appear silly to
+ send<A href="glossary.html#PGP"> PGP</A>-encrypted email through that
+ tunnel. However, if you suspect someone is snooping your traffic, then
+ it does make sense:</P>
+<UL>
+<LI>it protects the mail headers; they cannot even see who is mailing
+ who</LI>
+<LI>it protects against user bungles or software malfunctions that
+ accidentally send messages in the clear</LI>
+<LI>it makes any attack on the mail encryption much harder; they have to
+ break IPsec or break into your network before they can start on the
+ mail encryption</LI>
+</UL>
+<P>Similar arguments apply for<A href="glossary.html#SSL"> SSL</A>
+-encrypted web traffic or<A href="glossary.html#SSH"> SSH</A>-encrypted
+ remote login sessions, even for end-to-end IPsec tunnels between
+ systems in the two offices.</P>
+<H4><A name="fewer">Using fewer tunnels</A></H4>
+<P>It may also help to use fewer tunnels. For example, if all you
+ actually need encrypted is connections between:</P>
+<UL>
+<LI>mail servers at branch and head offices</LI>
+<LI>a few branch office users and the head office database server</LI>
+</UL>
+<P>You might build one tunnel per mail server and one per remote
+ database user, restricting traffic to those applications. This gives
+ the traffic analyst some information, however. He or she can
+ distinguish the tunnels by looking at information in the ESP header
+ and, given that distinction and the patterns of tunnel usage, might be
+ able to figure out something useful. Perhaps not, but why take the
+ risk?</P>
+<P>We suggest instead that you build one tunnel per branch office,
+ encrypting everything passing from head office to branches. This has a
+ number of advantages:</P>
+<UL>
+<LI>it is easier to build and administer</LI>
+<LI>it resists traffic analysis somewhat better</LI>
+<LI>it provides security for whatever you forgot. For example, if some
+ user at a remote office browses proprietary company data on some head
+ office web page (that the security people may not even know about!),
+ then that data is encrypted before it reaches the Internet.</LI>
+</UL>
+<P>Of course you might also want to add additional tunnels. For example,
+ if some of the database data is confidential and should not be exposed
+ even within the company, then you need protection from the user's
+ desktop to the database server. We suggest you do that in whatever way
+ seems appropriate -- IPsec, SSH or SSL might fit -- but, whatever you
+ choose, pass it between locations via a gateway-to-gateway IPsec tunnel
+ to provide some resistance to traffic analysis.</P>
+<H2><A name="primitives">Cryptographic components</A></H2>
+<P>IPsec combines a number of cryptographic techniques, all of them
+ well-known and well-analyzed. The overall design approach was
+ conservative; no new or poorly-understood components were included.</P>
+<P>This section gives a brief overview of each technique. It is intended
+ only as an introduction. There is more information, and links to
+ related topics, in our<A href="glossary.html"> glossary</A>. See also
+ our<A href="biblio.html"> bibliography</A> and cryptography<A href="web.html#crypto.link">
+ web links</A>.</P>
+<H3><A name="block.cipher">Block ciphers</A></H3>
+<P>The<A href="glossary.html#encryption"> encryption</A> in the<A href="glossary.html#ESP">
+ ESP</A> encapsulation protocol is done with a<A href="glossary.html#block">
+ block cipher</A>.</P>
+<P>We do not implement<A href="glossary.html#DES"> single DES</A>. It is<A
+href="politics.html#desnotsecure"> insecure</A>. Our default, and
+ currently only, block cipher is<A href="glossary.html#3DES"> triple DES</A>
+.</P>
+<P>The<A href="glossary.html#rijndael"> Rijndael</A> block cipher has
+ won the<A href="glossary.html#AES"> AES</A> competition to choose a
+ relacement for DES. It will almost certainly be added to FreeS/WAN and
+ to other IPsec implementations.<A href="web.html#patch"> Patches</A>
+ are already available.</P>
+<H3><A name="hash.ipsec">Hash functions</A></H3>
+<H4><A name="hmac.ipsec">The HMAC construct</A></H4>
+<P>IPsec packet authentication is done with the<A href="glossary.html#HMAC">
+ HMAC</A> construct. This is not just a hash of the packet data, but a
+ more complex operation which uses both a hashing algorithm and a key.
+ It therefore does more than a simple hash would. A simple hash would
+ only tell you that the packet data was not changed in transit, or that
+ whoever changed it also regenerated the hash. An HMAC also tells you
+ that the sender knew the HMAC key.</P>
+<P>For IPsec HMAC, the output of the hash algorithm is truncated to 96
+ bits. This saves some space in the packets. More important, it prevents
+ an attacker from seeing all the hash output bits and perhaps creating
+ some sort of attack based on that knowledge.</P>
+<H4>Choice of hash algorithm</H4>
+<P>The IPsec RFCs require two hash algorithms --<A href="glossary.html#MD5">
+ MD5</A> and<A href="glossary.html#SHA"> SHA-1</A> -- both of which
+ FreeS/WAN implements.</P>
+<P>Various other algorithms -- such as RIPEMD and Tiger -- are listed in
+ the RFCs as optional. None of these are in the FreeS/WAN distribution,
+ or are likely to be added, although user<A href="web.html#patch">
+ patches</A> exist for several of them.</P>
+<P>Additional hash algorithms --<A href="glossary.html#SHA-256">
+ SHA-256, SHA-384 and SHA-512</A> -- may be required to give hash
+ strength matching the strength of<A href="glossary.html#AES"> AES</A>.
+ These are likely to be added to FreeS/WAN along with AES.</P>
+<H3><A name="DH.keying">Diffie-Hellman key agreement</A></H3>
+<P>The<A href="glossary.html#DH"> Diffie-Hellman</A> key agreement
+ protocol allows two parties (A and B or<A href="glossary.html#alicebob">
+ Alice and Bob</A>) to agree on a key in such a way that an eavesdropper
+ who intercepts the entire conversation cannot learn the key.</P>
+<P>The protocol is based on the<A href="glossary.html#dlog"> discrete
+ logarithm</A> problem and is therefore thought to be secure.
+ Mathematicians have been working on that problem for years and seem no
+ closer to a solution, though there is no proof that an efficient
+ solution is impossible.</P>
+<H3><A name="RSA.auth">RSA authentication</A></H3>
+<P>The<A href="glossary.html#RSA"> RSA</A> algorithm (named for its
+ inventors -- Rivest, Shamir and Adleman) is a very widely used<A href="glossary.html#">
+ public key</A> cryptographic technique. It is used in IPsec as one
+ method of authenticating gateways for Diffie-Hellman key negotiation.</P>
+<H2><A name="structure">Structure of IPsec</A></H2>
+<P>There are three protocols used in an IPsec implementation:</P>
+<DL>
+<DT>ESP, Encapsulating Security Payload</DT>
+<DD>Encrypts and/or authenticates data</DD>
+<DT>AH, Authentication Header</DT>
+<DD>Provides a packet authentication service</DD>
+<DT>IKE, Internet Key Exchange</DT>
+<DD>Negotiates connection parameters, including keys, for the other two</DD>
+</DL>
+<P>The term &quot;IPsec&quot; is slightly ambiguous. In some contexts, it includes
+ all three of the above but in other contexts it refers only to AH and
+ ESP.</P>
+<H3><A name="IKE.ipsec">IKE (Internet Key Exchange)</A></H3>
+<P>The IKE protocol sets up IPsec (ESP or AH) connections after
+ negotiating appropriate parameters (algorithms to be used, keys,
+ connection lifetimes) for them. This is done by exchanging packets on
+ UDP port 500 between the two gateways.</P>
+<P>IKE (RFC 2409) was the outcome of a long, complex process in which
+ quite a number of protocols were proposed and debated. Oversimplifying
+ mildly, IKE combines:</P>
+<DL>
+<DT>ISAKMP (RFC 2408)</DT>
+<DD>The<STRONG> I</STRONG>nternet<STRONG> S</STRONG>ecurity<STRONG> A</STRONG>
+ssociation and<STRONG> K</STRONG>ey<STRONG> M</STRONG>anagement<STRONG>
+ P</STRONG>rotocol manages negotiation of connections and defines<A href="glossary.html#SA">
+ SA</A>s (Security Associations) as a means of describing connection
+ properties.</DD>
+<DT>IPsec DOI for ISAKMP (RFC 2407)</DT>
+<DD>A<STRONG> D</STRONG>omain<STRONG> O</STRONG>f<STRONG> I</STRONG>
+nterpretation fills in the details necessary to turn the rather abstract
+ ISAKMP protocol into a more tightly specified protocol, so it becomes
+ applicable in a particular domain.</DD>
+<DT>Oakley key determination protocol (RFC 2412)</DT>
+<DD>Oakley creates keys using the<A href="glossary.html#DH">
+ Diffie-Hellman</A> key agreement protocol.</DD>
+</DL>
+<P>For all the details, you would need to read the four<A href="rfc.html">
+ RFCs</A> just mentioned (over 200 pages) and a number of others. We
+ give a summary below, but it is far from complete.</P>
+<H4><A name="phases">Phases of IKE</A></H4>
+<P>IKE negotiations have two phases.</P>
+<DL>
+<DT>Phase one</DT>
+<DD>The two gateways negotiate and set up a two-way ISAKMP SA which they
+ can then use to handle phase two negotiations. One such SA between a
+ pair of gateways can handle negotiations for multiple tunnels.</DD>
+<DT>Phase two</DT>
+<DD>Using the ISAKMP SA, the gateways negotiate IPsec (ESP and/or AH)
+ SAs as required. IPsec SAs are unidirectional (a different key is used
+ in each direction) and are always negotiated in pairs to handle two-way
+ traffic. There may be more than one pair defined between two gateways.</DD>
+</DL>
+<P>Both of these phases use the UDP protocol and port 500 for their
+ negotiations.</P>
+<P>After both IKE phases are complete, you have IPsec SAs to carry your
+ encrypted data. These use the ESP or AH protocols. These protocols do
+ not have ports. Ports apply only to UDP or TCP.</P>
+<P>The IKE protocol is designed to be extremely flexible. Among the
+ things that can be negotiated (separately for each SA) are:</P>
+<UL>
+<LI>SA lifetime before rekeying</LI>
+<LI>encryption algorithm used. We currently support only<A href="glossary.html#3DES">
+ triple DES</A>. Single DES is<A href="politics.html#desnotsecure">
+ insecure</A>. The RFCs say you MUST do DES, SHOULD do 3DES and MAY do
+ various others. We do not do any of the others.</LI>
+<LI>authentication algorithms. We support<A href="glossary.html#MD5">
+ MD5</A> and<A href="glossary.html#SHA"> SHA</A>. These are the two the
+ RFCs require.</LI>
+<LI>choice of group for<A href="glossary.html#DH"> Diffie-Hellman</A>
+ key agreement. We currently support Groups 2 and 5 (which are defined
+ modulo primes of various lengths) and do not support Group 1 (defined
+ modulo a shorter prime, and therefore cryptographically weak) or groups
+ 3 and 4 (defined using elliptic curves). The RFCs require only Group 1.</LI>
+</UL>
+<P>The protocol also allows implementations to add their own encryption
+ algorithms, authentication algorithms or Diffie-Hellman groups. We do
+ not support any such extensions, but there are some<A href="web.html#patch">
+ patches</A> that do.</P>
+<P>There are a number of complications:</P>
+<UL>
+<LI>The gateways must be able to authenticate each other's identities
+ before they can create a secure connection. This host authentication is
+ part of phase one negotiations, and is a required prerequisite for
+ packet authentication used later. Host authentication can be done in a
+ variety of ways. Those supported by FreeS/WAN are discussed in our<A href="adv_config.html#auto-auth">
+ advanced configuration</A> document.</LI>
+<LI>Phase one can be done in two ways.
+<UL>
+<LI>Main Mode is required by the RFCs and supported in FreeS/WAN. It
+ uses a 6-packet exzchange.</LI>
+<LI>Aggressive Mode is somewhat faster (only 3 packets) but reveals more
+ to an eavesdropper. This is optional in the RFCs, not currently
+ supported by FreeS/WAN, and not likely to be.</LI>
+</UL>
+</LI>
+<LI>A new group exchange may take place after phase one but before phase
+ two, defining an additional group for use in the<A href="glossary.html#DH">
+ Diffie-Hellman</A> key agreement part of phase two. FreeS/WAN does not
+ currently support this.</LI>
+<LI>Phase two always uses Quick Mode, but there are two variants of
+ that:
+<UL>
+<LI>One variant provides<A href="glossary.html#PFS"> Perfect Forward
+ Secrecy (PFS)</A>. An attacker that obtains your long-term host
+ authentication key does not immediately get any of your short-term
+ packet encryption of packet authentication keys. He must conduct
+ another successful attack each time you rekey to get the short-term
+ keys. Having some short-term keys does not help him learn others. In
+ particular, breaking your system today does not let him read messages
+ he archived yestarday, assuming you've changed short-term keys in the
+ meanwhile. We enable PFS as the default.</LI>
+<LI>The other variant disables PFS and is therefore slightly faster. We
+ do not recommend this since it is less secure, but FreeS/WAN does
+ support it. You can enable it with a<VAR> pfs=no</VAR> statement in<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A>.</LI>
+<LI>The protocol provides no way to negotiate which variant will be
+ used. If one gateway is set for PFS and the other is not, the
+ negotiation fails. This has proved a fairly common source of
+ interoperation problems.</LI>
+</UL>
+</LI>
+<LI>Several types of notification message may be sent by either side
+ during either phase, or later. FreeS/WAN does not currently support
+ these, but they are a likely addition in future releases.</LI>
+<LI>There is a commit flag which may optionally be set on some messages.
+ The<A href="http://www.lounge.org/ike_doi_errata.html"> errata</A> page
+ for the RFCs includes two changes related to this, one to clarify the
+ description of its use and one to block a<A href="glossary.html#DOS">
+ denial of service</A> attack which uses it. We currently do not
+ implement this feature.</LI>
+</UL>
+<P>These complications can of course lead to problems, particularly when
+ two different implementations attempt to interoperate. For example, we
+ have seen problems such as:</P>
+<UL>
+<LI>Some implementations (often products crippled by<A href="politics.html#exlaw">
+ export laws</A>) have the insecure DES algorithm as their only
+ supported encryption method. Other parts of our documentation discuss
+ the<A href="politics.html#desnotsecure"> reasons we do not implement
+ single DES</A>, and<A href="interop.html#noDES"> how to cope with
+ crippled products</A>.</LI>
+<LI>Windows 2000 IPsec tries to negotiate using Aggressive Mode, which
+ we don't support. Later on, it uses the commit bit, which we also don't
+ support.</LI>
+<LI>Various implementations disable PFS by default, and therefore will
+ not talk to FreeS/WAN until you either turn on PFS on their end or turn
+ it off in FreeS/WAN with a<VAR> pfs=no</VAR> entry in the connection
+ description.</LI>
+<LI>FreeS/WAN's interaction with PGPnet is complicated by their use of
+ notification messages we do not yet support.</LI>
+</UL>
+<P>Despite this, we do interoperate successfully with many
+ implementations, including both Windows 2000 and PGPnet. Details are in
+ our<A href="interop.html"> interoperability</A> document.</P>
+<H4><A name="sequence">Sequence of messages in IKE</A></H4>
+<P>Each phase (see<A href="#phases"> previous section</A>)of IKE
+ involves a series of messages. In Pluto error messages, these are
+ abbreviated using:</P>
+<DL>
+<DT>M</DT>
+<DD><STRONG>M</STRONG>ain mode, settting up the keying channel (ISAKMP
+ SA)</DD>
+<DT>Q</DT>
+<DD><STRONG>Q</STRONG>uick mode, setting up the data channel (IPsec SA)</DD>
+<DT>I</DT>
+<DD><STRONG>I</STRONG>nitiator, the machine that starts the negotiation</DD>
+<DT>R</DT>
+<DD><STRONG>R</STRONG>esponder</DD>
+</DL>
+<P>For example, the six messages of a main mode negotiation, in
+ sequence, are labelled:</P>
+<PRE>       MI1 ----------&gt;
+           &lt;---------- MR1
+       MI2 ----------&gt; 
+           &lt;---------- MR2
+       MI3 ----------&gt;
+           &lt;---------- MR3</PRE>
+<H4><A name="struct.exchange">Structure of IKE messages</A></H4>
+<P>Here is our Pluto developer explaining some of this on the mailing
+ list:</P>
+<PRE>When one IKE system (for example, Pluto) is negotiating with another
+to create an SA, the Initiator proposes a bunch of choices and the
+Responder replies with one that it has selected.
+
+The structure of the choices is fairly complicated.  An SA payload
+contains a list of lists of &quot;Proposals&quot;.  The outer list is a set of
+choices: the selection must be from one element of this list.
+
+Each of these elements is a list of Proposals.  A selection must be
+made from each of the elements of the inner list.  In other words,
+*all* of them apply (that is how, for example, both AH and ESP can
+apply at once).
+
+Within each of these Proposals is a list of Transforms.  For each
+Proposal selected, one Transform must be selected (in other words,
+each Proposal provides a choice of Transforms).
+
+Each Transform is made up of a list of Attributes describing, well,
+attributes.  Such as lifetime of the SA.  Such as algorithm to be
+used.  All the Attributes apply to a Transform.
+
+You will have noticed a pattern here: layers alternate between being
+disjunctions (&quot;or&quot;) and conjunctions (&quot;and&quot;).
+
+For Phase 1 / Main Mode (negotiating an ISAKMP SA), this structure is
+cut back.  There must be exactly one Proposal.  So this degenerates to
+a list of Transforms, one of which must be chosen.</PRE>
+<H3><A name="services">IPsec Services, AH and ESP</A></H3>
+<P>IPsec offers two services,<A href="glossary.html#authentication">
+ authentication</A> and<A href="glossary.html#encryption"> encryption</A>
+. These can be used separately but are often used together.</P>
+<DL>
+<DT>Authentication</DT>
+<DD>Packet-level authentication allows you to be confident that a packet
+ came from a particular machine and that its contents were not altered
+ en route to you. No attempt is made to conceal or protect the contents,
+ only to assure their integrity. Packet authentication can be provided
+ separately using an<A href="glossary.html#AH"> Authentication Header</A>
+, described just below, or it can be included as part of the<A href="glossary.html#ESP">
+ ESP</A> (Encapsulated Security Payload) service, described in the
+ following section. That service offers encryption as well as
+ authentication. In either case, the<A href="glossary.html#HMAC"> HMAC</A>
+ construct is used as the authentication mechanism.
+<P>There is a separate authentication operation at the IKE level, in
+ which each gateway authenticates the other. This can be done in a
+ variety of ways.</P>
+</DD>
+<DT>Encryption</DT>
+<DD>Encryption allows you to conceal the contents of a message from
+ eavesdroppers.
+<P>In IPsec this is done using a<A href="glossary.html#block"> block
+ cipher</A> (normally<A href="glossary.html#3DES"> Triple DES</A> for
+ Linux). In the most used setup, keys are automatically negotiated, and
+ periodically re-negotiated, using the<A href="glossary.html#IKE"> IKE</A>
+ (Internet Key Exchange) protocol. In Linux FreeS/WAN this is handled by
+ the Pluto Daemon.</P>
+<P>The IPsec protocol offering encryption is<A href="glossary.html#ESP">
+ ESP</A>, Encapsulated Security Payload. It can also include a packet
+ authentication service.</P>
+</DD>
+</DL>
+<P>Note that<STRONG> encryption should always be used with some packet
+ authentication service</STRONG>. Unauthenticated encryption is
+ vulnerable to<A href="glossary.html#middle"> man-in-the-middle attacks</A>
+. Also note that encryption does not prevent<A href="glossary.html#traffic">
+ traffic analysis</A>.</P>
+<H3><A name="AH.ipsec">The Authentication Header (AH)</A></H3>
+<P>Packet authentication can be provided separately from encryption by
+ adding an authentication header (AH) after the IP header but before the
+ other headers on the packet. This is the subject of this section.
+ Details are in RFC 2402.</P>
+<P>Each of the several headers on a packet header contains a &quot;next
+ protocol&quot; field telling the system what header to look for next. IP
+ headers generally have either TCP or UDP in this field. When IPsec
+ authentication is used, the packet IP header has AH in this field,
+ saying that an Authentication Header comes next. The AH header then has
+ the next header type -- usually TCP, UDP or encapsulated IP.</P>
+<P>IPsec packet authentication can be added in transport mode, as a
+ modification of standard IP transport. This is shown in this diagram
+ from the RFC:</P>
+<PRE>                  BEFORE APPLYING AH
+            ----------------------------
+      IPv4  |orig IP hdr  |     |      |
+            |(any options)| TCP | Data |
+            ----------------------------
+
+                  AFTER APPLYING AH
+            ---------------------------------
+      IPv4  |orig IP hdr  |    |     |      |
+            |(any options)| AH | TCP | Data |
+            ---------------------------------
+            ||
+                 except for mutable fields</PRE>
+<P>Athentication can also be used in tunnel mode, encapsulating the
+ underlying IP packet beneath AH and an additional IP header.</P>
+<PRE>                         ||
+IPv4  | new IP hdr* |    | orig IP hdr*  |    |      |
+      |(any options)| AH | (any options) |TCP | Data |
+      ------------------------------------------------
+      ||
+      |           in the new IP hdr                  |</PRE>
+<P>This would normally be used in a gateway-to-gateway tunnel. The
+ receiving gateway then strips the outer IP header and the AH header and
+ forwards the inner IP packet.</P>
+<P>The mutable fields referred to are things like the time-to-live field
+ in the IP header. These cannot be included in authentication
+ calculations because they change as the packet travels.</P>
+<H4><A name="keyed">Keyed MD5 and Keyed SHA</A></H4>
+<P>The actual authentication data in the header is typically 96 bits and
+ depends both on a secret shared between sender and receiver and on
+ every byte of the data being authenticated. The technique used is<A href="glossary.html#HMAC">
+ HMAC</A>, defined in RFC 2104.</P>
+<P>The algorithms involved are the<A href="glossary.html#MD5"> MD5</A>
+ Message Digest Algorithm or<A href="glossary.html#SHA"> SHA</A>, the
+ Secure Hash Algorithm. For details on their use in this application,
+ see RFCs 2403 and 2404 respectively.</P>
+<P>For descriptions of the algorithms themselves, see RFC 1321 for MD5
+ and<A href="glossary.html#FIPS"> FIPS</A> (Federal Information
+ Processing Standard) number 186 from<A href="glossary.html#NIST"> NIST</A>
+, the US National Institute of Standards and Technology for SHA.<A href="biblio.html#schneier">
+<CITE> Applied Cryptography</CITE></A> covers both in some detail, MD5
+ starting on page 436 and SHA on 442.</P>
+<P>These algorithms are intended to make it nearly impossible for anyone
+ to alter the authenticated data in transit. The sender calculates a
+ digest or hash value from that data and includes the result in the
+ authentication header. The recipient does the same calculation and
+ compares results. For unchanged data, the results will be identical.
+ The hash algorithms are designed to make it extremely difficult to
+ change the data in any way and still get the correct hash.</P>
+<P>Since the shared secret key is also used in both calculations, an
+ interceptor cannot simply alter the authenticated data and change the
+ hash value to match. Without the key, he or she (or even the dreaded
+ They) cannot produce a usable hash.</P>
+<H4><A name="sequence">Sequence numbers</A></H4>
+<P>The authentication header includes a sequence number field which the
+ sender is required to increment for each packet. The receiver can
+ ignore it or use it to check that packets are indeed arriving in the
+ expected sequence.</P>
+<P>This provides partial protection against<A href="glossary.html#replay">
+ replay attacks</A> in which an attacker resends intercepted packets in
+ an effort to confuse or subvert the receiver. Complete protection is
+ not possible since it is necessary to handle legitmate packets which
+ are lost, duplicated, or delivered out of order, but use of sequence
+ numbers makes the attack much more difficult.</P>
+<P>The RFCs require that sequence numbers never cycle, that a new key
+ always be negotiated before the sequence number reaches 2^32-1. This
+ protects both against replays attacks using packets from a previous
+ cyclce and against<A href="glossary.html#birthday"> birthday attacks</A>
+ on the the packet authentication algorithm.</P>
+<P>In Linux FreeS/WAN, the sequence number is ignored for manually keyed
+ connections and checked for automatically keyed ones. In manual mode,
+ there is no way to negotiate a new key, or to recover from a sequence
+ number problem, so we don't use sequence numbers.</P>
+<H3><A name="ESP.ipsec">Encapsulated Security Payload (ESP)</A></H3>
+<P>The ESP protocol is defined in RFC 2406. It provides one or both of
+ encryption and packet authentication. It may be used with or without AH
+ packet authentication.</P>
+<P>Note that<STRONG> some form of packet authentication should<EM>
+ always</EM> be used whenever data is encrypted</STRONG>. Without
+ authentication, the encryption is vulnerable to active attacks which
+ may allow an enemy to break the encryption. ESP should<STRONG> always</STRONG>
+ either include its own authentication or be used with AH
+ authentication.</P>
+<P>The RFCs require support for only two mandatory encryption algorithms
+ --<A href="glossary.html#DES"> DES</A>, and null encryption -- and for
+ two authentication methods -- keyed MD5 and keyed SHA. Implementers may
+ choose to support additional algorithms in either category.</P>
+<P>The authentication algorithms are the same ones used in the IPsec<A href="glossary.html#AH">
+ authentication header</A>.</P>
+<P>We do not implement single DES since<A href="politics.html#desnotsecure">
+ DES is insecure</A>. Instead we provide<A href="glossary.html#3DES">
+ triple DES or 3DES</A>. This is currently the only encryption algorithm
+ supported.</P>
+<P>We do not implement null encryption since it is obviously insecure.</P>
+<H2><A name="modes">IPsec modes</A></H2>
+<P>IPsec can connect in two modes. Transport mode is a host-to-host
+ connection involving only two machines. In tunnel mode, the IPsec
+ machines act as gateways and trafiic for any number of client machines
+ may be carried.</P>
+<H3><A name="tunnel.ipsec">Tunnel mode</A></H3>
+<P>Security gateways are required to support tunnel mode connections. In
+ this mode the gateways provide tunnels for use by client machines
+ behind the gateways. The client machines need not do any IPsec
+ processing; all they have to do is route things to gateways.</P>
+<H3><A name="transport.ipsec">Transport mode</A></H3>
+<P>Host machines (as opposed to security gateways) with IPsec
+ implementations must also support transport mode. In this mode, the
+ host does its own IPsec processing and routes some packets via IPsec.</P>
+<H2><A name="parts">FreeS/WAN parts</A></H2>
+<H3><A name="KLIPS.ipsec">KLIPS: Kernel IPsec Support</A></H3>
+<P>KLIPS is<STRONG> K</STRONG>erne<STRONG>L</STRONG><STRONG> IP</STRONG>
+SEC<STRONG> S</STRONG>upport, the modifications necessary to support
+ IPsec within the Linux kernel. KILPS does all the actual IPsec
+ packet-handling, including</P>
+<UL>
+<LI>encryption</LI>
+<LI>packet authentication calculations</LI>
+<LI>creation of ESP and AH headers for outgoing packets</LI>
+<LI>interpretation of those headers on incoming packets</LI>
+</UL>
+<P>KLIPS also checks all non-IPsec packets to ensure they are not
+ bypassing IPsec security policies.</P>
+<H3><A name="Pluto.ipsec">The Pluto daemon</A></H3>
+<P><A href="manpage.d/ipsec_pluto.8.html">Pluto(8)</A> is a daemon which
+ implements the IKE protocol. It</P>
+<UL>
+<LI>handles all the Phase one ISAKMP SAs</LI>
+<LI>performs host authentication and negotiates with other gateways</LI>
+<LI>creates IPsec SAs and passes the data required to run them to KLIPS</LI>
+<LI>adjust routing and firewall setup to meet IPsec requirements. See
+ our<A href="firewall.html"> IPsec and firewalling</A> document for
+ details.</LI>
+</UL>
+<P>Pluto is controlled mainly by the<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A> configuration file.</P>
+<H3><A name="command">The ipsec(8) command</A></H3>
+<P>The<A href="manpage.d/ipsec.8.html"> ipsec(8)</A> command is a front
+ end shellscript that allows control over IPsec activity.</P>
+<H3><A name="ipsec.conf">Linux FreeS/WAN configuration file</A></H3>
+<P>The configuration file for Linux FreeS/WAN is</P>
+<PRE>        /etc/ipsec.conf</PRE>
+<P>For details see the<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A> manual page .</P>
+<H2><A name="key">Key management</A></H2>
+<P>There are several ways IPsec can manage keys. Not all are implemented
+ in Linux FreeS/WAN.</P>
+<H3><A name="current">Currently Implemented Methods</A></H3>
+<H4><A name="manual">Manual keying</A></H4>
+<P>IPsec allows keys to be manually set. In Linux FreeS/WAN, such keys
+ are stored with the connection definitions in /etc/ipsec.conf.</P>
+<P><A href="glossary.html#manual">Manual keying</A> is useful for
+ debugging since it allows you to test the<A href="glossary.html#KLIPS">
+ KLIPS</A> kernel IPsec code without the<A href="glossary.html#Pluto">
+ Pluto</A> daemon doing key negotiation.</P>
+<P>In general, however, automatic keying is preferred because it is more
+ secure.</P>
+<H4><A name="auto">Automatic keying</A></H4>
+<P>In automatic keying, the<A href="glossary.html#Pluto"> Pluto</A>
+ daemon negotiates keys using the<A href="glossary.html#IKE"> IKE</A>
+ Internet Key Exchange protocol. Connections are automatically re-keyed
+ periodically.</P>
+<P>This is considerably more secure than manual keying. In either case
+ an attacker who acquires a key can read every message encrypted with
+ that key, but automatic keys can be changed every few hours or even
+ every few minutes without breaking the connection or requiring
+ intervention by the system administrators. Manual keys can only be
+ changed manually; you need to shut down the connection and have the two
+ admins make changes. Moreover, they have to communicate the new keys
+ securely, perhaps with<A href="glossary.html#PGP"> PGP</A> or<A href="glossary.html#SSH">
+ SSH</A>. This may be possible in some cases, but as a general solution
+ it is expensive, bothersome and unreliable. Far better to let<A href="glossary.html#Pluto">
+ Pluto</A> handle these chores; no doubt the administrators have enough
+ to do.</P>
+<P>Also, automatic keying is inherently more secure against an attacker
+ who manages to subvert your gateway system. If manual keying is in use
+ and an adversary acquires root privilege on your gateway, he reads your
+ keys from /etc/ipsec.conf and then reads all messages encrypted with
+ those keys.</P>
+<P>If automatic keying is used, an adversary with the same privileges
+ can read /etc/ipsec.secrets, but this does not contain any keys, only
+ the secrets used to authenticate key exchanges. Having an adversary
+ able to authenticate your key exchanges need not worry you overmuch.
+ Just having the secrets does not give him any keys. You are still
+ secure against<A href="glossary.html#passive"> passive</A> attacks.
+ This property of automatic keying is called<A href="glossary.html#PFS">
+ perfect forward secrecy</A>, abbreviated PFS.</P>
+<P>Unfortunately, having the secrets does allow an<A href="glossary.html#active">
+ active attack</A>, specifically a<A href="glossary.html#middle">
+ man-in-the-middle</A> attack. Losing these secrets to an attacker may
+ not be quite as disastrous as losing the actual keys, but it is<EM>
+ still a serious security breach</EM>. These secrets should be guarded
+ as carefully as keys.</P>
+<H3><A name="notyet">Methods not yet implemented</A></H3>
+<H4><A name="noauth">Unauthenticated key exchange</A></H4>
+<P>It would be possible to exchange keys without authenticating the
+ players. This would support<A href="glossary.html#carpediem">
+ opportunistic encryption</A> -- allowing any two systems to encrypt
+ their communications without requiring a shared PKI or a previously
+ negotiated secret -- and would be secure against<A href="glossary.html#passive">
+ passive attacks</A>. It would, however, be highly vulnerable to active<A
+href="glossary.html#middle"> man-in-the-middle</A> attacks. RFC 2408
+ therefore specifies that all<A href="glossary.html#ISAKMP"> ISAKMP</A>
+ key management interactions<EM> must</EM> be authenticated.</P>
+<P>There is room for debate here. Should we provide immediate security
+ against<A href="glossary.html#passive"> passive attacks</A> and
+ encourage widespread use of encryption, at the expense of risking the
+ more difficult<A href="glossary.html#active"> active attacks</A>? Or
+ should we wait until we can implement a solution that can both be
+ widespread and offer security against active attacks?</P>
+<P>So far, we have chosen the second course, complying with the RFCs and
+ waiting for secure DNS (see<A href="glossary.html#DNS"> below</A>) so
+ that we can do<A href="glossary.html#carpediem"> opportunistic
+ encryption</A> right.</P>
+<H4><A name="DNS">Key exchange using DNS</A></H4>
+<P>The IPsec RFCs allow key exchange based on authentication services
+ provided by<A href="glossary.html#SDNS"> Secure DNS</A>. Once Secure
+ DNS service becomes widely available, we expect to make this the<EM>
+ primary key management method for Linux FreeS/WAN</EM>. It is the best
+ way we know of to support<A href="glossary.html#carpediem">
+ opportunistic encryption</A>, allowing two systems without a common PKI
+ or previous negotiation to secure their communication.</P>
+<P>We currently have code to acquire RSA keys from DNS but do not yet
+ have code to validate Secure DNS signatures.</P>
+<H4><A name="PKI">Key exchange using a PKI</A></H4>
+<P>The IPsec RFCs allow key exchange based on authentication services
+ provided by a<A href="glossary.html#PKI"> PKI</A> or Public Key
+ Infrastructure. With many vendors selling such products and many large
+ organisations building these infrastructures, this will clearly be an
+ important application of IPsec and one Linux FreeS/WAN will eventually
+ support.</P>
+<P>On the other hand, this is not as high a priority for Linux FreeS/WAN
+ as solutions based on<A href="glossary.html#SDNS"> secure DNS</A>. We
+ do not expect any PKI to become as universal as DNS.</P>
+<P>Some<A href="web.html#patch"> patches</A> to handle authentication
+ with X.509 certificates, which most PKIs use, are available.</P>
+<H4><A name="photuris">Photuris</A></H4>
+<P><A href="glossary.html#photuris">Photuris</A> is another key
+ management protocol, an alternative to IKE and ISAKMP, described in
+ RFCs 2522 and 2523 which are labelled &quot;experimental&quot;. Adding Photuris
+ support to Linux FreeS/WAN might be a good project for a volunteer. The
+ likely starting point would be the OpenBSD photurisd code.</P>
+<H4><A name="skip">SKIP</A></H4>
+<P><A href="glossary.html#SKIP">SKIP</A> is yet another key management
+ protocol, developed by Sun. At one point it was fairly widely used, but
+ it now seems moribund, displaced by IKE. Sun now (as of Solaris 8.0)
+ ship an IPsec implementation using IKE. We have no plans to implement
+ SKIP. If a user were to implement it, we would almost certainly not
+ want to add the code to our distribution.</P>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="politics.html">Previous</A>
+<A HREF="mail.html">Next</A>
+</BODY>
+</HTML>
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
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+<A HREF="toc.html">Contents</A>
+<A HREF="testing.html">Previous</A>
+<A HREF="adv_config.html">Next</A>
+<HR>
+<H1><A name="kernelconfig">Kernel configuration for FreeS/WAN</A></H1>
+<P> This section lists many of the options available when configuring a
+ Linux kernel, and explains how they should be set on a FreeS/WAN IPsec
+ gateway.</P>
+<H2><A name="notall">Not everyone needs to worry about kernel
+ configuration</A></H2>
+<P>Note that in many cases you do not need to mess with these.</P>
+<P> You may have a Linux distribution which comes with FreeS/WAN
+ installed (see this<A href="intro.html#products"> list</A>). In that
+ case, you need not do a FreeS/WAN installation or a kernel
+ configuration. Of course, you might still want to configure and rebuild
+ your kernel to improve performance or security. This can be done with
+ standard tools described in the<A href="http://www.linuxdoc.org/HOWTO/Kernel-HOWTO.html">
+ Kernel HowTo</A>.</P>
+<P>If you need to install FreeS/WAN, then you do need to configure a
+ kernel. However, you may choose to do that using the simplest
+ procedure:</P>
+<UL>
+<LI>Configure, build and test a kernel for your system before adding
+ FreeS/WAN. See the<A href="http://www.linuxdoc.org/HOWTO/Kernel-HOWTO.html">
+ Kernel HowTo</A> for details.<STRONG> This step cannot be skipped</STRONG>
+. FreeS/WAN needs the results of your configuration.</LI>
+<LI>Then use FreeS/WAN's<VAR> make oldgo</VAR> command. This sets
+ everything FreeS/WAN needs and retains your values everywhere else.</LI>
+</UL>
+<P> This document is for those who choose to configure their FreeS/WAN
+ kernel themselves.</P>
+<H2><A name="assume">Assumptions and notation</A></H2>
+<P> Help text for most kernel options is included with the kernel files,
+ and is accessible from within the configuration utilities. We assume
+ you will refer to that, and to the<A href="http://www.linuxdoc.org/HOWTO/Kernel-HOWTO.html">
+ Kernel HowTo</A>, as necessary. This document covers only the
+ FreeS/WAN-specific aspects of the problem.</P>
+<P> To avoid duplication, this document section does not cover settings
+ for the additional IPsec-related kernel options which become available
+ after you have patched your kernel with FreeS/WAN patches. There is
+ help text for those available from within the configuration utility.</P>
+<P> We assume a common configuration in which the FreeS/WAN IPsec
+ gateway is also doing ipchains(8) firewalling for a local network, and
+ possibly masquerading as well.</P>
+<P> Some suggestions below are labelled as appropriate for &quot;a true
+ paranoid&quot;. By this we mean they may cause inconvenience and it is not
+ entirely clear they are necessary, but they appear to be the safest
+ choice. Not using them might entail some risk. Of course one suggested
+ mantra for security administrators is: &quot;I know I'm paranoid. I wonder
+ if I'm paranoid enough.&quot;</P>
+<H3><A name="labels">Labels used</A></H3>
+<P> Six labels are used to indicate how options should be set. We mark
+ the labels with [square brackets]. For two of these labels, you have no
+ choice:</P>
+<DL>
+<DT>[required]</DT>
+<DD>essential for FreeS/WAN operation.</DD>
+<DT>[incompatible]</DT>
+<DD>incompatible with FreeS/WAN.</DD>
+</DL>
+<P>those must be set correctly or FreeS/WAN will not work</P>
+<P>FreeS/WAN should work with any settings of the others, though of
+ course not all combinations have been tested. We do label these in
+ various ways, but<EM> these labels are only suggestions</EM>.</P>
+<DL>
+<DT>[recommended]</DT>
+<DD>useful on most FreeS/WAN gateways</DD>
+<DT>[disable]</DT>
+<DD>an unwelcome complication on a FreeS/WAN gateway.</DD>
+<DT>[optional]</DT>
+<DD>Your choice. We outline issues you might consider.</DD>
+<DT>[anything]</DT>
+<DD>This option has no direct effect on FreeS/WAN and related tools, so
+ you should be able to set it as you please.</DD>
+</DL>
+<P> Of course complexity is an enemy in any effort to build secure
+ systems.<STRONG> For maximum security, any feature that can reasonably
+ be turned off should be</STRONG>. &quot;If in doubt, leave it out.&quot;</P>
+<H2><A name="kernelopt">Kernel options for FreeS/WAN</A></H2>
+<P> Indentation is based on the nesting shown by 'make menuconfig' with
+ a 2.2.16 kernel for the i386 architecture.</P>
+<DL>
+<DT><A name="maturity">Code maturity and level options</A></DT>
+<DD>
+<DL>
+<DT><A name="devel">Prompt for development ... code/drivers</A></DT>
+<DD>[optional] If this is<VAR> no</VAR>, experimental drivers are not
+ shown in later menus.
+<P>For most FreeS/WAN work,<VAR> no</VAR> is the preferred setting.
+ Using new or untested components is too risky for a security gateway.</P>
+<P>However, for some hardware (such as the author's network cards) the
+ only drivers available are marked<VAR> new/experimental</VAR>. In such
+ cases, you must enable this option or your cards will not appear under
+ &quot;network device support&quot;. A true paranoid would leave this option off
+ and replace the cards.</P>
+</DD>
+<DT>Processor type and features</DT>
+<DD>[anything]</DD>
+<DT>Loadable module support</DT>
+<DD>
+<DL>
+<DT>Enable loadable module support</DT>
+<DD>[optional] A true paranoid would disable this. An attacker who has
+ root access to your machine can fairly easily install a bogus module
+ that does awful things, provided modules are enabled. A common tool for
+ attackers is a &quot;rootkit&quot;, a set of tools the attacker uses once he or
+ she has become root on your system. The kit introduces assorted
+ additional compromises so that the attacker will continue to &quot;own&quot; your
+ system despite most things you might do to recovery the situation. For
+ Linux, there is a tool called<A href="http://www.sans.org/newlook/resources/IDFAQ/knark.htm">
+ knark</A> which is basically a rootkit packaged as a kernel module.
+<P>With modules disabled, an attacker cannot install a bogus module. The
+ only way he can achieve the same effects is to install a new kernel and
+ reboot. This is considerably more likely to be noticed.</P>
+<P>Many FreeS/WAN gateways run with modules enabled. This simplifies
+ some administrative tasks and some ipchains features are available only
+ as modules. Once an enemy has root on your machine your security is
+ nil, so arguably defenses which come into play only in that situation
+ are pointless.</P>
+<P></P>
+</DD>
+<DT>Set version information ....</DT>
+<DD>[optional] This provides a check to prevent loading modules compiled
+ for a different kernel.</DD>
+<DT>Kernel module loader</DT>
+<DD>[disable] It gives little benefit on a typical FreeS/WAN gate and
+ entails some risk.</DD>
+</DL>
+</DD>
+<DT>General setup</DT>
+<DD>We list here only the options that matter for FreeS/WAN.
+<DL>
+<DT>Networking support</DT>
+<DD>[required]</DD>
+<DT>Sysctl interface</DT>
+<DD>[optional] If this option is turned on and the<VAR> /proc</VAR>
+ filesystem installed, then you can control various system behaviours by
+ writing to files under<VAR> /proc/sys</VAR>. For example:
+<PRE>        echo 1 &gt; /proc/sys/net/ipv4/ipforward</PRE>
+ turns IP forwarding on.
+<P>Disabling this option breaks many firewall scripts. A true paranoid
+ would disable it anyway since it might conceivably be of use to an
+ attacker.</P>
+</DD>
+</DL>
+</DD>
+<DT>Plug and Play support</DT>
+<DD>[anything]</DD>
+<DT>Block devices</DT>
+<DD>[anything]</DD>
+<DT>Networking options</DT>
+<DD>
+<DL>
+<DT>Packet socket</DT>
+<DD>[optional] This kernel feature supports tools such as tcpdump(8)
+ which communicate directly with network hardware, bypassing kernel
+ protocols. This is very much a two-edged sword:
+<UL>
+<LI>such tools can be very useful to the firewall admin, especially
+ during initial testing</LI>
+<LI>should an evildoer breach your firewall, such tools could give him
+ or her a great deal of information about the rest of your network</LI>
+</UL>
+ We recommend disabling this option on production gateways.</DD>
+<DT><A name="netlink">Kernel/User netlink socket</A></DT>
+<DD>[optional] Required if you want to use<A href="#adv"> advanced
+ router</A> features.</DD>
+<DT>Routing messages</DT>
+<DD>[optional]</DD>
+<DT>Netlink device emulation</DT>
+<DD>[optional]</DD>
+<DT>Network firewalls</DT>
+<DD>[recommended] You need this if the IPsec gateway also functions as a
+ firewall.
+<P>Even if the IPsec gateway is not your primary firewall, we suggest
+ setting this so that you can protect the gateway with at least basic
+ local packet filters.</P>
+</DD>
+<DT>Socket filtering</DT>
+<DD>[disable] This enables an older filtering interface. We suggest
+ using ipchains(8) instead. To do that, set the &quot;Network firewalls&quot;
+ option just above, and not this one.</DD>
+<DT>Unix domain sockets</DT>
+<DD>[required] These sockets are used for communication between the<A href="manpage.d/ipsec.8.html">
+ ipsec(8)</A> commands and the<A href="manpage.d/ipsec_pluto.8.html">
+ ipsec_pluto(8)</A> daemon.</DD>
+<DT>TCP/IP networking</DT>
+<DD>[required]
+<DL>
+<DT>IP: multicasting</DT>
+<DD>[anything]</DD>
+<DT><A name="adv">IP: advanced router</A></DT>
+<DD>[optional] This gives you policy routing, which some people have
+ used to good advantage in their scripts for FreeS/WAN gateway
+ management. It is not used in our distributed scripts, so not required
+ unless you want it for custom scripts. It requires the<A href="#netlink">
+ netlink</A> interface between kernel code and the iproute2(8) command.</DD>
+<DT>IP: kernel level autoconfiguration</DT>
+<DD>[disable] It gives little benefit on a typical FreeS/WAN gate and
+ entails some risk.</DD>
+<DT>IP: firewall packet netlink device</DT>
+<DD>[disable]</DD>
+<DT>IP: transparent proxy support</DT>
+<DD>[optional] This is required in some firewall configurations, but
+ should be disabled unless you have a definite need for it.</DD>
+<DT>IP: masquerading</DT>
+<DD>[optional] Required if you want to use<A href="glossary.html#non-routable">
+ non-routable</A> private IP addresses for your local network.</DD>
+<DT>IP: Optimize as router not host</DT>
+<DD>[recommended]</DD>
+<DT>IP: tunneling</DT>
+<DD>[required]</DD>
+<DT>IP: GRE tunnels over IP</DT>
+<DD>[anything]</DD>
+<DT>IP: aliasing support</DT>
+<DD>[anything]</DD>
+<DT>IP: ARP daemon support (EXPERIMENTAL)</DT>
+<DD>Not required on most systems, but might prove useful on
+ heavily-loaded gateways.</DD>
+<DT>IP: TCP syncookie support</DT>
+<DD>[recommended] It provides a defense against a<A href="glossary.html#DOS">
+ denial of service attack</A> which uses bogus TCP connection requests
+ to waste resources on the victim machine.</DD>
+<DT>IP: Reverse ARP</DT>
+<DD></DD>
+<DT>IP: large window support</DT>
+<DD>[recommended] unless you have less than 16 meg RAM</DD>
+</DL>
+</DD>
+<DT>IPv6</DT>
+<DD>[optional] FreeS/WAN does not currently support IPv6, though work on
+ integrating FreeS/WAN with the Linux IPv6 stack has begun.<A href="compat.html#ipv6">
+ Details</A>.
+<P> It should be possible to use IPv4 FreeS/WAN on a machine which also
+ does IPv6. This combination is not yet well tested. We would be quite
+ interested in hearing results from anyone expermenting with it, via the<A
+href="mail.html"> mailing list</A>.</P>
+<P> We do not recommend using IPv6 on production FreeS/WAN gateways
+ until more testing has been done.</P>
+</DD>
+<DT>Novell IPX</DT>
+<DD>[disable]</DD>
+<DT>Appletalk</DT>
+<DD>[disable] Quite a few Linux installations use IP but also have some
+ other protocol, such as Appletalk or IPX, for communication with local
+ desktop machines. In theory it should be possible to configure IPsec
+ for the IP side of things without interfering with the second protocol.
+<P>We do not recommend this. Keep the software on your gateway as simple
+ as possible. If you need a Linux-based Appletalk or IPX server, use a
+ separate machine.</P>
+</DD>
+</DL>
+</DD>
+<DT>Telephony support</DT>
+<DD>[anything]</DD>
+<DT>SCSI support</DT>
+<DD>[anything]</DD>
+<DT>I2O device support</DT>
+<DD>[anything]</DD>
+<DT>Network device support</DT>
+<DD>[anything] should work, but there are some points to note.
+<P>The development team test almost entirely on 10 or 100 megabit
+ Ethernet and modems. In principle, any device that can do IP should be
+ just fine for IPsec, but in the real world any device that has not been
+ well-tested is somewhat risky. By all means try it, but don't bet your
+ project on it until you have solid test results.</P>
+<P>If you disabled experimental drivers in the<A href="#maturity"> Code
+ maturity</A> section above, then those drivers will not be shown here.
+ Check that option before going off to hunt for missing drivers.</P>
+<P>If you want Linux to automatically find more than one ethernet
+ interface at boot time, you need to:</P>
+<UL>
+<LI>compile the appropriate driver(s) into your kernel. Modules will not
+ work for this</LI>
+<LI>add a line such as
+<PRE>
+   append=&quot;ether=0,0,eth0 ether=0,0,eth1&quot;
+</PRE>
+ to your /etc/lilo.conf file. In some cases you may need to specify
+ parameters such as IRQ or base address. The example uses &quot;0,0&quot; for
+ these, which tells the system to search. If the search does not succeed
+ on your hardware, then you should retry with explicit parameters. See
+ the lilo.conf(5) man page for details.</LI>
+<LI>run lilo(8)</LI>
+</UL>
+ Having Linux find the cards this way is not necessary, but is usually
+ more convenient than loading modules in your boot scripts.</DD>
+<DT>Amateur radio support</DT>
+<DD>[anything]</DD>
+<DT>IrDA (infrared) support</DT>
+<DD>[anything]</DD>
+<DT>ISDN subsystem</DT>
+<DD>[anything]</DD>
+<DT>Old CDROM drivers</DT>
+<DD>[anything]</DD>
+<DT>Character devices</DT>
+<DD>The only required character device is:
+<DL>
+<DT>random(4)</DT>
+<DD>[required] This is a source of<A href="glossary.html#random"> random</A>
+ numbers which are required for many cryptographic protocols, including
+ several used in IPsec.
+<P>If you are comfortable with C source code, it is likely a good idea
+ to go in and adjust the<VAR> #define</VAR> lines in<VAR>
+ /usr/src/linux/drivers/char/random.c</VAR> to ensure that all sources
+ of randomness are enabled. Relying solely on keyboard and mouse
+ randomness is dubious procedure for a gateway machine. You could also
+ increase the randomness pool size from the default 512 bytes (128
+ 32-bit words).</P>
+</DD>
+</DL>
+</DD>
+<DT>Filesystems</DT>
+<DD>[anything] should work, but we suggest limiting a gateway machine to
+ the standard Linux ext2 filesystem in most cases.</DD>
+<DT>Network filesystems</DT>
+<DD>[disable] These systems are an unnecessary risk on an IPsec gateway.</DD>
+<DT>Console drivers</DT>
+<DD>[anything]</DD>
+<DT>Sound</DT>
+<DD>[anything] should work, but we suggest enabling sound only if you
+ plan to use audible alarms for firewall problems.</DD>
+<DT>Kernel hacking</DT>
+<DD>[disable] This might be enabled on test machines, but should not be
+ on production gateways.</DD>
+</DL>
+</DD>
+</DL>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="testing.html">Previous</A>
+<A HREF="adv_config.html">Next</A>
+</BODY>
+</HTML>
diff --git a/doc/kernel.notes b/doc/kernel.notes
new file mode 100644
index 000000000..675e80be3
--- /dev/null
+++ b/doc/kernel.notes
@@ -0,0 +1,173 @@
+Notes on Red Hat 5.2 kernel installation (See Addendum for RH6.1)
+=================================================================
+
+Warning: We (the FreeS/WAN Project http://www.xs4all.nl/~freeswan/)
+had nothing to do with designing the kernel installation process.  This
+document explains some tricky points that we wish we had been told.
+We don't know if these notes apply to systems other than Red Hat 5.2.
+This is meant as a supplement to other kernel install guides (such as
+the Red Hat 5.2 Installation Guide section 11.6).
+
+Goal: install a new kernel on RH5.2 in such a way that it doesn't
+interfere with any other kernels.  This should be repeatable: each new
+kernel should have this property.  Each should remain bootable.
+
+Problem: there are several components to a kernel, and each must be
+segregated.  How are the parts kept apart?  How are they found?
+
+All the parts live in the file system, so it all comes down to
+pathnames.  Well, except for the fiddly bits in /etc/lilo.conf.  What
+are the parts?
+
+	/lib/modules/VER/	directory for kernel modules
+	/boot/vmlinux-VER	the kernel
+	/boot/System.map-VER	the kernel symbol table
+	/boot/initrd-VER.img 	the initial ramdisk (for modules needed
+				at boot time -- usually not necessary)
+	/boot/boot.b		the second-stage loader
+	/boot/map		the map file, an index into system index for
+				all files used by boot loader (all kernels,
+				all initrds, perhaps /boot/boot.b, and itself)
+
+This list does not include /boot/module-info-VER.  That is supplied
+by RedHat, and it isn't clear to me how to build it or why.
+
+In each entry, I've used "VER" to signify a version number.  For
+RH-supplied kernels, these look like 2.0.36-0.7 (the original 5.2) or
+2.0.36-3 (the kernel updates).
+
+There are also symbolic links:
+	/lib/modules/preferred	created by /etc/rc.d/rc.sysinit
+	/boot/System.map	created by /etc/rc.d/rc.sysinit
+	/boot/module-info	created by /etc/rc.d/rc.sysinit
+	/vmlinuz		created by ???
+I don't know when the /vmlinuz symlink is set up and I don't know
+for what it is used.
+
+If you follow the RH procedures, documented in 11.6 of their Installation
+Guide, all your VERs will be 2.0.36.  This is very bad: all your builds
+will step on each other.  Worse, your new module directory will be half
+picked up when you boot a stock RH kernel binary! 
+
+It is important to know how the various parts of the built kernel are
+found at booting.
+
+- the kernel path is specified in the image= option in lilo.conf.
+  (Lilo.conf may specify several and one is selected at boot time
+  by default or user selection.)  The kernel is loaded by the
+  boot loader.
+
+- The initial ramdisk is a per-image option (initrd=) specified in
+  lilo.conf.  (It isn't described in the RH5.2 lilo.conf(5) manpage!).
+  The initial ramdisk is loaded into RAM by the boot loader.
+
+- Since the boot loader doesn't know about the file system, it needs a
+  map to figure out which absolute disk blocks to load, and where.
+  This is /boot/map.  It is built by the lilo command (also known as
+  the map installer).  It will have indices for the all the kernels
+  that can be booted, all their initial ram disks, perhaps
+  /boot/boot.b, and itself.  This is why moving the blocks of these
+  files throws off the boot loader -- lilo must be rerun after even a
+  cp command to one of them.
+
+- the modules directory is found two different ways.  Unfortunately,
+  they don't mesh properly:
+
+  + at boot time, /etc/rc.d/rc.sysinit tries to figure out the correct
+    subdirectory of /lib/modules, using the .rhkmvtag trick (see
+    later).  It then builds a symlink /lib/modules/preferred to
+    record this.  It also invokes depmod to build the module
+    dependency info.  At the same time, it creates the symlinks
+    /boot/System.map and /boot/module-info, using the inferred
+    value for VER!
+
+  + modprobe and friends stupidly look first in /lib/modules/2.0.36
+    (more precisely, /lib/modules/`uname -r`) and then in
+    /lib/modules/preferred.  So if there is a /lib/modules/2.0.36 and
+    it is the wrong one, you are in trouble.
+
+  If there is no /lib/modules/2.0.36, then both searches above will
+  agree (a very Good Thing).  So I recommend strongly that you not
+  have a /lib/boot/2.0.36 at boot time.  Unfortunately, you will get
+  one during the kernel install process.  Be sure to rename it.  I
+  suggest using 2.0.36-x (for some unique x) as VER.
+
+- Red Hat supplied /lib/modules/VER directories contain a hidden file
+  .rhkmvtag.  This file contains exactly one line.  This line is
+  exactly the same as the contents of /proc/version while the
+  corresponding kernel is running.  For the stock kernel, the line is:
+Linux version 2.0.36 (root@porky.redhat.com) (gcc version 2.7.2.3) #1 Tue Dec 29 13:11:13 EST 1998
+
+- At boot time, /etc/rc.d/rc.sysinit uses the .rhkmvtag files to
+  figure out which of the /lib/modules/* directories matches the
+  kernel.  If it could figure out the directory, it uses this
+  information to set the symlinks mentioned above.  It then runs
+  depmod to build the module dependency information (in
+  /lib/modules/preferred/modules.dep, if it created the
+  /lib/modules/preferred symlink).  I recommend looking at the code.
+
+- The documented kernel install procedures DO NOT fill in the
+  .rhkmvtag file for the new modules directory!  So you should do so
+  by hand.  You have to figure out what the contents should be.  Here
+  is is a command that will do the job, assuming that
+  /usr/src/linux/vmlinux is the kernel associated with
+  /lib/modules/2.0.36/:
+
+	strings /usr/src/linux/vmlinux \
+	| grep 'x version' >/lib/modules/2.0.36/.rhkmvtag
+
+I've recommended (above) that you use 2.0.36-x for VER when you install
+a kernel.  What should x be?  I have found that there is a hidden file
+/usr/src/linux/.version which contains a counter that gets incremented
+whenever you do a "make install" in the kernel (see target
+newversion).  There are some other times that it gets incremented, but
+I think that it all works out.  It also gets incorporated into the
+resulting kernel's /proc/version, prefixed with ``#''.  This makes it
+a natural.
+
+Here is a script to do the recommended renaming:
+
+   # VER will eventually need to be updated
+   VER=2.0.36
+   VERX=${VER}-`cat /usr/src/linux/.version`
+
+   strings /usr/src/linux/vmlinux | grep 'x version' >/lib/modules/$VER/.rhkmvtag
+   mv /lib/modules/$VER /lib/modules/$VERX
+   mv /boot/System.map-$VER /boot/System.map-$VERX
+   mv /boot/vmlinuz-$VER /boot/vmlinuz-$VERX
+
+And, if an initrd has been built (usually it is best to arrange not to
+use one -- see the Red Hat Installation Guide):
+
+   /sbin/mkinitrd /boot/initrd-$VERX.img $VERX
+
+Remember: a new lilo.conf entry is needed for the new kernel, and then
+the lilo command will need to be rerun.
+
+Now that kernel installs don't overwrite the results of previous ones,
+you will need to manually delete the components and their lilo entry
+to get rid of them.
+
+Please send comments, additions, and corrections to:
+
+Hugh Redelmeier
+hugh@mimosa.com  voice: +1 416 482-8253
+
+
+Addendum: Red Hat 6.1
+=====================
+
+The kernel supplied with RH6.1 kernel is out of date, so you might
+wish to use a newer one.
+
+Much of the description for 5.2 still applies, but the procedure is
+quite different because the .version file is no longer used.  Instead,
+the top-level Makefile contains a definition EXTRAVERSION which adds a
+qualifier to the version for most purposes.  No manual renaming is
+required.
+
+Before building the kernel, change EXTRAVERSION by editing
+/usr/src/linux/Makefile, and make an appropriate entry in /etc/lilo.conf.
+
+EXTRAVERSION is a feature of the standard kernel sources, not just the
+ones supplied by Red Hat.
diff --git a/doc/mail.html b/doc/mail.html
new file mode 100644
index 000000000..68b5d8cd8
--- /dev/null
+++ b/doc/mail.html
@@ -0,0 +1,216 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
+H5 { font-family: sans-serif }
+H6 { font-family: sans-serif }
+SUB { font-size: smaller }
+SUP { font-size: smaller }
+PRE { font-family: monospace }
+--></STYLE>
+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="ipsec.html">Previous</A>
+<A HREF="web.html">Next</A>
+<HR>
+<H1><A name="lists">Mailing lists and newsgroups</A></H1>
+<H2><A name="list.fs">Mailing lists about FreeS/WAN</A></H2>
+<H3><A name="projlist">The project mailing lists</A></H3>
+<P>The Linux FreeS/WAN project has several email lists for user support,
+ bug reports and software development discussions.</P>
+<P>We had a single list on clinet.fi for several years (Thanks, folks!),
+ then one list on freeswan.org, but now we've split into several lists:</P>
+<DL>
+<DT><A href="mailto:users-request@lists.freeswan.org?body=subscribe">
+users</A></DT>
+<DD>
+<UL>
+<LI>The general list for discussing use of the software</LI>
+<LI>The place for seeking<STRONG> help with problems</STRONG> (but
+ please check the<A href="faq.html"> FAQ</A> first).</LI>
+<LI>Anyone can post.</LI>
+</UL>
+</DD>
+<DT><A href="mailto:bugs-request@lists.freeswan.org?body=subscribe">bugs</A>
+</DT>
+<DD>
+<UL>
+<LI>For<STRONG> bug reports</STRONG>.</LI>
+<LI>If you are not certain what is going on -- could be a bug, a
+ configuration error, a network problem, ... -- please post to the users
+ list instead.</LI>
+<LI>Anyone can post.</LI>
+</UL>
+</DD>
+<DT><A href="mailto:design-request@lists.freeswan.org?body=subscribe">
+design</A></DT>
+<DD>
+<UL>
+<LI><STRONG>Design discussions</STRONG>, for people working on FreeS/WAN
+ development or others with an interest in design and security issues.</LI>
+<LI>It would be a good idea to read the existing design papers (see this<A
+href="intro.html#applied"> list</A>) before posting.</LI>
+<LI>Anyone can post.</LI>
+</UL>
+</DD>
+<DT><A href="mailto:announce-request@lists.freeswan.org?body=subscribe">
+announce</A></DT>
+<DD>
+<UL>
+<LI>A<STRONG> low-traffic</STRONG> list.</LI>
+<LI><STRONG>Announcements</STRONG> about FreeS/WAN and related software.</LI>
+<LI>All posts here are also sent to the users list. You need not
+ subscribe to both.</LI>
+<LI>Only the FreeS/WAN team can post.</LI>
+<LI>If you have something you feel should go on this list, send it to<VAR>
+ announce-admin@lists.freeswan.org</VAR>. Unless it is obvious, please
+ include a short note explaining why we should post it.</LI>
+</UL>
+</DD>
+<DT><A href="mailto:briefs-request@lists.freeswan.org?body=subscribe">
+briefs</A></DT>
+<DD>
+<UL>
+<LI>A<STRONG> low-traffic</STRONG> list.</LI>
+<LI><STRONG>Weekly summaries</STRONG> of activity on the users list.</LI>
+<LI>All posts here are also sent to the users list. You need not
+ subscribe to both.</LI>
+<LI>Only the FreeS/WAN team can post.</LI>
+</UL>
+</DD>
+</DL>
+<P>To subscribe to any of these, you can:</P>
+<UL>
+<LI>just follow the links above</LI>
+<LI>use our<A href="http://www.freeswan.org/mail.html"> web interface</A>
+</LI>
+<LI>send mail to<VAR> listname</VAR>-request@lists.freeswan.org with a
+ one-line message body &quot;subscribe&quot;</LI>
+</UL>
+<P>Archives of these lists are available via the<A href="http://www.freeswan.org/mail.html">
+ web interface</A>.</P>
+<H4><A name="which.list">Which list should I use?</A></H4>
+<P>For most questions, please check the<A href="faq.html"> FAQ</A>
+ first, and if that does not have an answer, ask on the users list. &quot;My
+ configuration doesn't work.&quot; does not belong on the bugs list, and &quot;Can
+ FreeS/WAN do such-and-such&quot; or &quot;How do I configure it to...&quot; do not
+ belong in design discussions.</P>
+<P>Cross-posting the same message to two or more of these lists is
+ discouraged. Quite a few people read more than one list and getting
+ multiple copies is annoying.</P>
+<H4><A name="policy.list">List policies</A></H4>
+<P><STRONG>US citizens or residents are asked not to post code to the
+ lists, not even one-line bug fixes</STRONG>. The project cannot accept
+ code which might entangle it in US<A href="politics.html#exlaw"> export
+ restrictions</A>.</P>
+<P>Non-subscribers can post to some of these lists. This is necessary;
+ someone working on a gateway install who encounters a problem may not
+ have access to a subscribed account.</P>
+<P>Some spam turns up on these lists from time to time. For discussion
+ of why we do not attempt to filter it, see the<A href="faq.html#spam">
+ FAQ</A>. Please do not clutter the lists with complaints about this.</P>
+<H3><A name="archive">Archives of the lists</A></H3>
+<P>Searchable archives of the old single list have existed for some
+ time. At time of writing, it is not yet clear how they will change for
+ the new multi-list structure.</P>
+<UL>
+<LI><A href="http://www.sandelman.ottawa.on.ca/linux-ipsec">Canada</A></LI>
+<LI><A href="http://www.nexial.com">Holland</A></LI>
+</UL>
+<P>Note that these use different search engines. Try both.</P>
+<P>Archives of the new lists are available via the<A href="http://www.freeswan.org/mail.html">
+ web interface</A>.</P>
+<H2><A name="indexes">Indexes of mailing lists</A></H2>
+<P><A href="http://paml.net/">PAML</A> is the standard reference for<STRONG>
+ P</STRONG>ublicly<STRONG> A</STRONG>ccessible<STRONG> M</STRONG>ailing<STRONG>
+ L</STRONG>ists. When we last checked, it had over 7500 lists on an
+ amazing variety of topics. It also has FAQ information and a search
+ engine.</P>
+<P>There is an index of<A href="http://oslab.snu.ac.kr/~djshin/linux/mail-list/index.shtml">
+ Linux mailing lists</A> available.</P>
+<P>A list of<A href="http://xforce.iss.net/maillists/otherlists.php">
+ computer security mailing lists</A>, with descriptions.</P>
+<H2><A name="otherlists">Lists for related software and topics</A></H2>
+<P>Most links in this section point to subscription addresses for the
+ various lists. Send the one-line message &quot;subscribe<VAR> list_name</VAR>
+&quot; to subscribe to any of them.</P>
+<H3><A NAME="28_3_1">Products that include FreeS/WAN</A></H3>
+<P>Our introduction document gives a<A href="intro.html#products"> list
+ of products that include FreeS/WAN</A>. If you have, or are
+ considering, one of those, check the supplier's web site for
+ information on mailing lists for their users.</P>
+<H3><A name="linux.lists">Linux mailing lists</A></H3>
+<UL>
+<LI><A href="mailto:majordomo@vger.kernel.org">
+linux-admin@vger.kernel.org</A>, for Linux system administrators</LI>
+<LI><A href="mailto:netfilter-request@lists.samba.org">
+netfilter@lists.samba.org</A>, about Netfilter, which replaces IPchains
+ in kernels 2.3.15 and later</LI>
+<LI><A href="mailto:security-audit-request@ferret.lmh.ox.ac.uk">
+security-audit@ferret.lmh.ox.ac.uk</A>, for people working on security
+ audits of various Linux programs</LI>
+<LI><A href="mailto:securedistros-request@humbolt.geo.uu.nl">
+securedistros@humbolt.geo.uu.nl</A>, for discussion of issues common to
+ all the half dozen projects working on secure Linux distributions.</LI>
+</UL>
+<P>Each of the scure distribution projects also has its own web site and
+ mailing list. Some of the sites are:</P>
+<UL>
+<LI><A href="http://bastille-linux.org/">Bastille Linux</A> scripts to
+ harden Redhat, e.g. by changing permissions and modifying inialisation
+ scripts</LI>
+<LI><A href="http://immunix.org/">Immunix</A> take a different approach,
+ using a modified compiler to build kernel and utilities with better
+ resistance to various types of overflow and exploit</LI>
+<LI>the<A href="glossary.html#NSA"> NSA</A> have contractors working on
+ a<A href="glossary.html#SElinux"> Security Enhanced Linux</A>,
+ primarily adding stronger access control mechanisms. You can download
+ the current version (which interestingly is under GPL and not export
+ resrtricted) or subscribe to the mailing list from the<A href="http://www.nsa.gov/selinux">
+ project web page</A>.</LI>
+</UL>
+<H3><A name="ietf">Lists for IETF working groups</A></H3>
+<P>Each<A href="glossary.html#IETF"> IETF</A> working group has an
+ associated mailing list where much of the work takes place.</P>
+<UL>
+<LI><A href="mailto:majordomo@lists.tislabs.com">ipsec@lists.tislabs.com</A>
+, the IPsec<A href="http://www.ietf.org/html.charters/ipsec-charter.html">
+ working group</A>. This is where the protocols are discussed, new
+ drafts announced, and so on. By now, the IPsec working group is winding
+ down since the work is essentially complete. A<A href="http://www.sandelman.ottawa.on.ca/ipsec/">
+ list archive</A> is available.</LI>
+<LI><A href="mailto:ipsec-policy-request@vpnc.org">IPsec policy</A>
+ list, and its<A href="http://www.vpnc.org/ipsec-policy/"> archive</A></LI>
+<LI><A href="mailto:ietf-ipsra-request@vpnc.org">IP secure remote access</A>
+ list, and its<A href="http://www.vpnc.org/ietf-ipsra/mail-archive/">
+ archive</A></LI>
+</UL>
+<H3><A name="other">Other mailing lists</A></H3>
+<UL>
+<LI><A href="mailto:ipc-announce-request@privacy.org">
+ipc-announce@privacy.org</A> a low-traffic list with announcements of
+ developments in privacy, encryption and online civil rights</LI>
+<LI>a VPN mailing list's<A href="http://kubarb.phsx.ukans.edu/~tbird/vpn.html">
+ home page</A></LI>
+</UL>
+<H2><A name="newsgroups">Usenet newsgroups</A></H2>
+<UL>
+<LI>sci.crypt</LI>
+<LI>sci.crypt.research</LI>
+<LI>comp.dcom.vpn</LI>
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+<HR>
+<H1><A name="makecheck">How to configure to use &quot;make check&quot;</A></H1>
+<H2><A NAME="38_1">What is &quot;make check&quot;</A></H2>
+<P> &quot;make check&quot; is a target in the top level makefile. It takes care of
+ running a number of unit and system tests to confirm that FreeSWAN has
+ been compiled correctly, and that no new bugs have been introduced.</P>
+<P> As FreeSWAN contains both kernel and userspace components, doing
+ testing of FreeSWAN requires that the kernel be simulated. This is
+ typically difficult to do as a kernel requires that it be run on bare
+ hardware. A technology has emerged that makes this simpler. This is<A HREF="http://user-mode-linux.sourceforge.net">
+ User Mode Linux</A>.</P>
+<P> User-Mode Linux is a way to build a Linux kernel such that it can
+ run as a process under another Linux (or in the future other) kernel.
+ Presently, this can only be done for 2.4 guest kernels. The host kernel
+ can be 2.2 or 2.4.</P>
+<P> &quot;make check&quot; expects to be able to build User-Mode Linux kernels
+ with FreeSWAN included. To do this it needs to have some files
+ downloaded and extracted prior to running &quot;make check&quot;. This is
+ described in the<A HREF="umltesting.html"> UML testing</A> document.</P>
+<P> After having run the example in the UML testing document and
+ successfully brought up the four machine combination, you are ready to
+ use &quot;make check&quot;</P>
+<H2><A NAME="38_2">Running &quot;make check&quot;</A></H2>
+<P> &quot;make check&quot; works by walking the FreeSWAN source tree invoking the
+ &quot;check&quot; target at each node. At present there are tests defined only
+ for the <CODE>klips</CODE> directory. These tests will use the UML
+ infrastructure to test out pieces of the <CODE>klips</CODE> code.</P>
+<P> The results of the tests can be recorded. If the environment
+ variable <CODE>$REGRESSRESULTS</CODE> is non-null, then the results of
+ each test will be recorded. This can be used as part of a nightly
+ regression testing system, see<A HREF="nightly.html"> Nightly testing</A>
+ for more details.</P>
+<P> &quot;make check&quot; otherwise prints a minimal amount of output for each
+ test, and indicates pass/fail status of each test as they are run.
+ Failed tests do not cause failure of the target in the form of exit
+ codes.</P>
+<H1><A NAME="39">How to write a &quot;make check&quot; test</A></H1>
+<H2><A NAME="39_1">Structure of a test</A></H2>
+<P> Each test consists of a set of directories under <CODE>testing/</CODE>
+. There are directories for <CODE>klips</CODE>, <CODE>pluto</CODE>, <CODE>
+packaging</CODE> and <CODE>libraries</CODE>. Each directory has a list
+ of tests to run is stored in a file called <CODE>TESTLIST</CODE> in
+ that directory. e.g. <CODE>testing/klips/TESTLIST</CODE>.</P>
+<H2 NAME="TESTLIST"><A NAME="39_2">The TESTLIST</A></H2>
+<P> This isn't actually a shell script. It just looks like one. Some
+ tools other than /bin/sh process it. Lines that start with # are
+ comments.</P>
+<PRE>
+# test-kind     directory-containing-test       expectation     [PR#]
+</PRE>
+<P>The first word provides the test type, detailed below.</P>
+<P> The second word is the name of the test to run. This the directory
+ in which the test case is to be found..</P>
+<P>The third word may be one of:</P>
+<DL>
+<DT> blank/good</DT>
+<DD>the test is believed to function, report failure</DD>
+<DT> bad</DT>
+<DD> the test is known to fail, report unexpected success</DD>
+<DT> suspended</DT>
+<DD> the test should not be run</DD>
+</DL>
+<P> The fourth word may be a number, which is a PR# if the test is
+ failing.</P>
+<H2><A NAME="39_3">Test kinds</A></H2>
+ The test types are:
+<DL>
+<DT>skiptest</DT>
+<DD>means run no test.</DD>
+<DT>ctltest</DT>
+<DD>means run a single system without input/output.</DD>
+<DT>klipstest</DT>
+<DD>means run a single system with input/output networks</DD>
+<DT><A HREF="#umlplutotest">umlplutotest</A></DT>
+<DD>means run a pair of systems</DD>
+<DT><A HREF="#umlXhost">umlXhost</A></DT>
+<DD>run an arbitrary number of systems</DD>
+<DT>suntest (TBD)</DT>
+<DD>means run a quad of east/west/sunrise/sunset</DD>
+<DT>roadtest (TBD)</DT>
+<DD>means run a trio of east-sunrise + warrior</DD>
+<DT>extrudedtest (TBD)</DT>
+<DD>means run a quad of east-sunrise + warriorsouth + park</DD>
+<DT>mkinsttest</DT>
+<DD>a test of the &quot;make install&quot; machinery.</DD>
+<DT>kernel_test_patch</DT>
+<DD>a test of the &quot;make kernelpatch&quot; machinery.</DD>
+</DL>
+ Tests marked (TBD) have yet to be fully defined.
+<P> Each test directory has a file in it called <CODE>testparams.sh</CODE>
+. This file sets a number of environment variables to define the
+ parameters of the test.</P>
+<H2><A NAME="39_4">Common parameters</A></H2>
+<DL>
+<DT>TESTNAME</DT>
+<DD>the name of the test (repeated for checking purposes)</DD>
+<DT>TEST_TYPE</DT>
+<DD>the type of the test (repeat of type type above)</DD>
+<DT>TESTHOST</DT>
+<DD>the name of the UML machine to run for the test, typically &quot;east&quot; or
+ &quot;west&quot;</DD>
+<DT>TEST_PURPOSE</DT>
+<DD>The purpose of the test is one of:
+<DL>
+<DT>goal</DT>
+<DD>The goal purpose is where a test is defined for code that is not yet
+ finished. The test indicates when the goals have in fact been reached.</DD>
+<DT>regress</DT>
+<DD>This is a test to determine that a previously existing bug has been
+ repaired. This test will initially be created to reproduce the bug in
+ isolation, and then the bug will be fixed.</DD>
+<DT>exploit</DT>
+<DD>This is a set of packets/programs that causes a vulnerability to be
+ exposed. It is a specific variation of the regress option.</DD>
+</DL>
+</DD>
+<DT>TEST_GOAL_ITEM</DT>
+<DT></DT>
+<DD>in the case of a goal test, this is a reference to the requirements
+ document</DD>
+<DT>TEST_PROB_REPORT</DT>
+<DD>in the case of regression test, this the problem report number from
+ GNATS</DD>
+<DT>TEST_EXPLOIT_URL</DT>
+<DD>in the case of an exploit, this is a URL referencing the paper
+ explaining the origin of the test and the origin of exploit software</DD>
+<DT>REF_CONSOLE_OUTPUT</DT>
+<DD>a file in the test directory that contains the sanitized console
+ output against which to compare the output of the actual test.</DD>
+<DT>REF_CONSOLE_FIXUPS</DT>
+<DD>a list of scripts (found in <CODE>klips/test/fixups</CODE>) to apply
+ to sanitize the console output of the machine under test. These are
+ typically perl, awk or sed scripts that remove things in the kernel
+ output that change each time the test is run and/or compiled.</DD>
+<DT>INIT_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode prior to starting the tests. This file will usually
+ set up any eroute's and SADB entries that are required for the test.</P>
+<P>Lines beginning with # are skipped. Blank lines are skipped.
+ Otherwise, a shell prompted is waited for each time (consisting of <CODE>
+\n#</CODE>) and then the command is sent. Note that the prompt is waited
+ for before the command and not after, so completion of the last command
+ in the script is not required. This is often used to invoke a program
+ to monitor the system, e.g. <CODE>ipsec pf_key</CODE>.</P>
+</DD>
+<DT>RUN_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode, before the packets are sent. On single machine tests,
+ this script doesn't provide any more power than INIT_SCRIPT, but is
+ implemented for consistency's sake.</P>
+</DD>
+<DT>FINAL_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode after the final packet is sent. Similar to
+ INIT_SCRIPT, above. If not specified, then the single command &quot;halt&quot; is
+ sent. If specified, then the script should end with a halt command to
+ nicely shutdown the UML.</P>
+</DD>
+<DT>CONSOLEDIFFDEBUG</DT>
+<DD>If set to &quot;true&quot; then the series of console fixups (see
+ REF_CONSOLE_FIXUPS) will be output after it is constructed. (It should
+ be set to &quot;false&quot;, or unset otherwise)</DD>
+<DT>NETJIGDEBUG</DT>
+<DD>If set to &quot;true&quot; then the series of console fixups (see
+ REF_CONSOLE_FIXUPS) will be output after it is constructed. (It should
+ be set to &quot;false&quot;, or unset otherwise)</DD>
+<DT>NETJIGTESTDEBUG</DT>
+<DD> If set to &quot;netjig&quot;, then the results of talking to the <CODE>
+uml_netjig</CODE> will be printed to stderr during the test. In
+ addition, the jig will be invoked with --debug, which causes it to log
+ its process ID, and wait 60 seconds before continuing. This can be used
+ if you are trying to debug the <CODE>uml_netjig</CODE> program itself.</DD>
+<DT>HOSTTESTDEBUG</DT>
+<DD> If set to &quot;hosttest&quot;, then the results of taling to the consoles of
+ the UMLs will be printed to stderr during the test.</DD>
+<DT>NETJIGWAITUSER</DT>
+<DD> If set to &quot;waituser&quot;, then the scripts will wait forever for user
+ input before they shut the tests down. Use this is if you are debugging
+ through the kernel.</DD>
+<DT>PACKETRATE</DT>
+<DD> A number, in miliseconds (default is 500ms) at which packets will
+ be replayed by the netjig.</DD>
+</DL>
+<H2><A NAME="39_5">KLIPStest paramaters</A></H2>
+<P> The klipstest function starts a program (<CODE>
+testing/utils/uml_netjig/uml_netjig</CODE>) to setup a bunch of I/O
+ sockets (that simulate network interfaces). It then exports the
+ references to these sockets to the environment and invokes (using
+ system()) a given script. It waits for the script to finish.</P>
+
+<!-- <IMG SRC="single_netjig.png" ALT="block diagram of uml_netjig"> -->
+<P> The script invoked (<CODE>testing/utils/host-test.tcl</CODE>) is a
+ TCL<A HREF="http://expect.nist.gov/"> expect</A> script that arranges
+ to start the UML and configure it appropriately for the test. The
+ configuration is done with the script given above for<VAR> INIT_SCRIPT</VAR>
+. The TCL script then forks, leaves the UML in the background and exits.
+ uml_netjig continues. It then starts listening to the simulated network
+ answering ARPs and inserting packets as appropriate.</P>
+<P> The klipstest function invokes <CODE>uml_netjig</CODE> with
+ arguments to capture output from network interface(s) and insert
+ packets as appropriate:</P>
+<DL>
+<DT>PUB_INPUT</DT>
+<DD>a<A HREF="http://www.tcpdump.org/"> pcap</A> file to feed in on the
+ public (encrypted) interface. (typically, eth1)</DD>
+<DT>PRIV_INPUT</DT>
+<DD>a pcap file to feed in on the private (plain-text) interface
+ (typically, eth0).</DD>
+<DT>REF_PUB_OUTPUT</DT>
+<DD>a text file containing tcpdump output. Packets on the public (eth1)
+ interface are captured to a<A HREF="http://www.tcpdump.org/"> pcap</A>
+ file by <CODE>uml_netjig</CODE>. The klipstest function then uses
+ tcpdump on the file to produce text output, which is compared to the
+ file given.</DD>
+<DT>REF_PUB_FILTER</DT>
+<DD>a program that will filter the TCPDUMP output to do further
+ processing. Defaults to &quot;cat&quot;.</DD>
+<DT>REF_PRIV_OUTPUT</DT>
+<DD>a text file containing tcpdump output. Packets on the private (eth0)
+ interface are captured and compared after conversion by tcpdump, as
+ with<VAR> REFPUBOUTPUT</VAR>.</DD>
+<DT>REF_PRIV_FILTER</DT>
+<DD>a program that will filter the TCPDUMP output to do further
+ processing. Defaults to &quot;cat&quot;.</DD>
+<DT>EXITONEMPTY</DT>
+<DD>a flag for <CODE>uml_netjig</CODE>. It should contain
+ &quot;--exitonempty&quot; of uml_netjig should exit when all of the input (<VAR>
+PUBINPUT</VAR>,<VAR>PRIVINPUT</VAR>) packets have been injected.</DD>
+<DT>ARPREPLY</DT>
+<DD>a flag for <CODE>uml_netjig</CODE>. It should contain &quot;--arpreply&quot;
+ if <CODE>uml_netjig</CODE> should reply to ARP requests. One will
+ typically set this to avoid having to fudge the ARP cache manually.</DD>
+<DT>TCPDUMPFLAGS</DT>
+<DD>a set of flags for the tcpdump used when converting captured output.
+ Typical values will include &quot;-n&quot; to turn off DNS, and often &quot;-E&quot; to set
+ the decryption key (tcpdump 3.7.1 and higher only) for ESP packets. The
+ &quot;-t&quot; flag (turn off timestamps) is provided automatically</DD>
+<DT>NETJIG_EXTRA</DT>
+<DD>additional comments to be sent to the netjig. This may arrange to
+ record or create additional networks, or may toggle options.</DD>
+</DL>
+<H2><A NAME="39_6">mkinsttest paramaters</A></H2>
+<P> The basic concept of the <CODE>mkinsttest</CODE> test type is that
+ it performs a &quot;make install&quot; to a temporary $DESTDIR. The resulting
+ tree can then be examined to determine if it was done properly. The
+ files can be uninstalled to determine if the file list was correct, or
+ the contents of files can be examined more precisely.</P>
+<DL>
+<DT>INSTALL_FLAGS</DT>
+<DD>If set, then an install will be done. This provides the set of flags
+ to provide for the install. The target to be used (usually &quot;install&quot;)
+ must be among the flags.</DD>
+<DT>POSTINSTALL_SCRIPT</DT>
+<DD>If set, a script to run after initial &quot;make install&quot;. Two arguments
+ are provided: an absolute path to the root of the FreeSWAN src tree,
+ and an absolute path to the temporary installation area.</DD>
+<DT>INSTALL2_FLAGS</DT>
+<DD>If set, a second install will be done using these flags. Similarly
+ to INSTALL_FLAGS, the target must be among the flags.</DD>
+<DT>UNINSTALL_FLAGS</DT>
+<DD>If set, an uninstall will be done using these flags. Similarly to
+ INSTALL_FLAGS, the target (usually &quot;uninstall&quot;) must be among the
+ flags.</DD>
+<DT>REF_FIND_f_l_OUTPUT</DT>
+<DD>If set, a <CODE>find $ROOT ( -type f -or -type -l )</CODE> will be
+ done to get a list of a real files and symlinks. The resulting file
+ will be compared to the file listed by this option.</DD>
+<DT>REF_FILE_CONTENTS</DT>
+<DD>If set, it should point to a file containing records for the form:
+<PRE>
+  
+<!--VARIABLE-->
+reffile</(null)>   
+<!--VARIABLE-->
+samplefile</(null)>
+</PRE>
+ one record per line. A diff between the provided reference file, and
+ the sample file (located in the temporary installation root) will be
+ done for each record.</DD>
+</DL>
+<H2><A NAME="39_7">rpm_build_install_test paramaters</A></H2>
+<P> The <CODE>rpm_build_install_test</CODE> type is to verify that the
+ proper packing list is produced by &quot;make rpm&quot;, and that the mechanisms
+ for building the kernel modules produce consistent results.</P>
+<DL>
+<DT>RPM_KERNEL_SOURCE</DT>
+<DD>Point to an extracted copy of the RedHat kernel source code.
+ Variables from the environment may be used.</DD>
+<DT>REF_RPM_CONTENTS</DT>
+<DD>This is a file containing one record per line. Each record consists
+ of a RPM name (may contain wildcards) and a filename to compare the
+ contents to. The RPM will be located and a file list will be produced
+ with rpm2cpio.</DD>
+</DL>
+<H2><A NAME="39_8">libtest paramaters</A></H2>
+<P> The libtest test is for testing library routines. The library file
+ is expected to provided an <CODE>#ifdef</CODE> by the name of<VAR>
+ library</VAR>
+<!--CODE_MAIN</CODE-->
+. The libtest type invokes the C compiler to compile this
+ file, links it against <CODE>libfreeswan.a</CODE> (to resolve any other
+ dependancies) and runs the test with the <CODE>-r</CODE> argument to
+ invoke a regression test.</(null)></P>
+<P>The library test case is expected to do a self-test, exiting with
+ status code 0 if everything is okay, and with non-zero otherwise. A
+ core dump (exit code greater than 128) is noted specifically.</P>
+<P> Unlike other tests, there are no subdirectories required, or other
+ parameters to set.</P>
+<H2 NAME="umlplutotest"><A NAME="39_9">umlplutotest paramaters</A></H2>
+<P> The umlplutotest function starts a pair of user mode line processes.
+ This is a 2-host version of umlXhost. The &quot;EAST&quot; and &quot;WEST&quot; slots are
+ defined.</P>
+<H2 NAME="umlXhost"><A NAME="39_10">umlXhost parameters</A></H2>
+<P> The umlXtest function starts an arbitrary number of user mode line
+ processes.</P>
+
+<!-- <IMG SRC="single_netjig.png" ALT="block diagram of uml_netjig"> -->
+<P> The script invoked (<CODE>testing/utils/Xhost-test.tcl</CODE>) is a
+ TCL<A HREF="http://expect.nist.gov/"> expect</A> script that arranges
+ to start each UML and configure it appropriately for the test. It then
+ starts listening (using uml_netjig) to the simulated network answering
+ ARPs and inserting packets as appropriate.</P>
+<P> umlXtest has a series of slots, each of which should be filled by a
+ host. The list of slots is controlled by the variable, XHOST_LIST. This
+ variable should be set to a space seperated list of slots. The former
+ umlplutotest is now implemented as a variation of the umlXhost test,
+ with XHOST_LIST=&quot;EAST WEST&quot;.</P>
+<P> For each host slot that is defined, a series of variables should be
+ filled in, defining what configuration scripts to use for that host.</P>
+<P> The following are used to control the console input and output to
+ the system. Where the string ${host} is present, the host slot should
+ be filled in. I.e. for the two host system with XHOST_LIST=&quot;EAST WEST&quot;,
+ then the variables: EAST_INIT_SCRIPT and WEST_INIT_SCRIPT will exist.</P>
+<DL>
+<DT>${host}HOST</DT>
+<DD>The name of the UML host which will fill this slot</DD>
+<DT>${host}_INIT_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode prior to starting the tests. This file will usually
+ set up any eroute's and SADB entries that are required for the test.
+ Similar to INIT_SCRIPT, above.</P>
+</DD>
+<DT>${host}_RUN_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode, before the packets are sent. This set of commands is
+ run after all of the virtual machines are initialized. I.e. after
+ EAST_INIT_SCRIPT<B> AND</B> WEST_INIT_SCRIPT. This script can therefore
+ do things that require that all machines are properly configured.</P>
+</DD>
+<DT>${host}_RUN2_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode, after the packets are sent. This set of commands is
+ run before any of the virtual machines have been shut down. (I.e.
+ before EAST_FINAL_SCRIPT<B> AND</B> WEST_FINAL_SCRIPT.) This script can
+ therefore catch post-activity status reports.</P>
+</DD>
+<DT>${host}_FINAL_SCRIPT</DT>
+<DD>
+<P>a file of commands that is fed into the virtual machine's console in
+ single user mode after the final packet is sent. Similar to
+ INIT_SCRIPT, above. If not specified, then the single command &quot;halt&quot; is
+ sent. Note that when this script is run, the other virtual machines may
+ already have been killed. If specified, then the script should end with
+ a halt command to nicely shutdown the UML.</P>
+</DD>
+<DT>REF_${host}_CONSOLE_OUTPUT</DT>
+<DD>Similar to REF_CONSOLE_OUTPUT, above.</DD>
+</DL>
+<P>Some additional flags apply to all hosts:</P>
+<DL>
+<DT>REF_CONSOLE_FIXUPS</DT>
+<DD>a list of scripts (found in <CODE>klips/test/fixups</CODE>) to apply
+ to sanitize the console output of the machine under test. These are
+ typically perl, awk or sed scripts that remove things in the kernel
+ output that change each time the test is run and/or compiled.</DD>
+</DL>
+<P> In addition to input to the console, the networks may have input fed
+ to them:</P>
+<DL>
+<DT>EAST_INPUT/WEST_INPUT</DT>
+<DD>a<A HREF="http://www.tcpdump.org/"> pcap</A> file to feed in on the
+ private network side of each network. The &quot;EAST&quot; and &quot;WEST&quot; here refer
+ to the networks, not the hosts.</DD>
+<DT>REF_PUB_FILTER</DT>
+<DD>a program that will filter the TCPDUMP output to do further
+ processing. Defaults to &quot;cat&quot;.</DD>
+<DT>REF_EAST_FILTER/REF_WEST_FILTER</DT>
+<DD>a program that will filter the TCPDUMP output to do further
+ processing. Defaults to &quot;cat&quot;.</DD>
+&lt;
+<DT>TCPDUMPFLAGS</DT>
+<DD>a set of flags for the tcpdump used when converting captured output.
+ Typical values will include &quot;-n&quot; to turn off DNS, and often &quot;-E&quot; to set
+ the decryption key (tcpdump 3.7.1 and higher only) for ESP packets. The
+ &quot;-t&quot; flag (turn off timestamps) is provided automatically</DD>
+<DT>REF_EAST_OUTPUT/REF_WEST_OUTPUT</DT>
+<DD>a text file containing tcpdump output. Packets on the private (eth0)
+ interface are captured and compared after conversion by tcpdump, as
+ with<VAR> REF_PUB_OUTPUT</VAR>.</DD>
+<P> There are two additional environment variables that may be set on
+ the command line:</P>
+<DL>
+<DT> NETJIGVERBOSE=verbose export NETJIGVERBOSE</DT>
+<DD> If set, then the test output will be &quot;chatty&quot;, and let you know
+ what commands it is running, and as packets are sent. Without it set,
+ the output is limited to success/failure messages.</DD>
+<DT> NETJIGTESTDEBUG=netjig export NETJIGTESTDEBUG</DT>
+<DD> This will enable debugging of the communication with uml_netjig,
+ and turn on debugging in this utility. This does not imply
+ NETJIGVERBOSE.</DD>
+</DL>
+<DT> HOSTTESTDEBUG=hosttest export HOSTTESTDEBUG</DT>
+<DD> This will show all interactions with the user-mode-linux consoles</DD>
+</DL>
+<H2 NAME="kernelpatch"><A NAME="39_11">kernel_patch_test paramaters</A></H2>
+<P> The kernel_patch_test function takes some kernel source, copies it
+ with lndir, and then applies the patch as produced by &quot;make
+ kernelpatch&quot;.</P>
+<P> The following are used to control the input and output to the
+ system:</P>
+<DL>
+<DT>KERNEL_NAME</DT>
+<DD>the kernel name, typically something like &quot;linus&quot; or &quot;rh&quot;</DD>
+<DT>KERNEL_VERSION</DT>
+<DD>the kernel version number, as in &quot;2.2&quot; or &quot;2.4&quot;.</DD>
+<DT>KERNEL_${KERNEL_NAME}${KERNEL_VERSION}_SRC</DT>
+<DD>This variable should set in the environment, probably in
+ ~/freeswan-regress-env.sh. Examples of this variables would be
+ KERNEL_LINUS2_0_SRC or KERNEL_RH7_3_SRC. This variable should point to
+ an extracted copy of the kernel source in question.</DD>
+<DT>REF_PATCH_OUTPUT</DT>
+<DD>a copy of the patch output to compare against</DD>
+<DT>KERNEL_PATCH_LEAVE_SOURCE</DT>
+<DD>If set to a non-empty string, then the patched kernel source is not
+ removed at the end of the test. This will typically be set in the
+ environment while debugging.</DD>
+</DL>
+<H2 NAME="modtest"><A NAME="39_12">module_compile paramaters</A></H2>
+<P> The module_compile test attempts to build the KLIPS module against a
+ given set of kernel source. This is also done by the RPM tests, but in
+ a very specific manner.</P>
+<P> There are two variations of this test - one where the kernel either
+ doesn't need to be configured, or is already done, and tests were there
+ is a local configuration file.</P>
+<P> Where the kernel doesn't need to be configured, the kernel source
+ that is found is simply used. It may be a RedHat-style kernel, where
+ one can cause it to configure itself via rhconfig.h-style definitions.
+ Or, it may just be a kernel tree that has been configured.</P>
+<P> If the variable KERNEL_CONFIG_FILE is set, then a new directory is
+ created for the kernel source. It is populated with lndir(1). The
+ referenced file is then copied in as .config, and &quot;make oldconfig&quot; is
+ used to configure the kernel. This resulting kernel is then used as the
+ reference source.</P>
+<P> In all cases, the kernel source is found the same was for the
+ kernelpatch test, i.e. via KERNEL_VERSION/KERNEL_NAME and
+ KERNEL_${KERNEL_NAME}${KERNEL_VERSION}_SRC.</P>
+<P> Once there is kernel source, the module is compiled using the
+ top-level &quot;make module&quot; target.</P>
+<P> The test is considered successful if an executable is found in
+ OUTPUT/module/ipsec.o at the end of the test.</P>
+<DL>
+<DT>KERNEL_NAME</DT>
+<DD>the kernel name, typically something like &quot;linus&quot; or &quot;rh&quot;</DD>
+<DT>KERNEL_VERSION</DT>
+<DD>the kernel version number, as in &quot;2.2&quot; or &quot;2.4&quot;.</DD>
+<DT>KERNEL_${KERNEL_NAME}${KERNEL_VERSION}_SRC</DT>
+<DD>This variable should set in the environment, probably in
+ ~/freeswan-regress-env.sh. Examples of this variables would be
+ KERNEL_LINUS2_0_SRC or KERNEL_RH7_3_SRC. This variable should point to
+ an extracted copy of the kernel source in question.</DD>
+<DT>KERNEL_CONFIG_FILE</DT>
+<DD>The configuration file for the kernel.</DD>
+<DT>KERNEL_PATCH_LEAVE_SOURCE</DT>
+<DD>If set to a non-empty string, then the configured kernel source is
+ not removed at the end of the test. This will typically be set in the
+ environment while debugging.</DD>
+<DT>MODULE_DEF_INCLUDE</DT>
+<DD>The include file that will be used to configure the KLIPS module,
+ and possibly the kernel source.</DD>
+</DL>
+<H1><A NAME="40">Current pitfalls</A></H1>
+<DL>
+<DT> &quot;tcpdump dissector&quot; not available.</DT>
+<DD> This is a non-fatal warning. If uml_netjig is invoked with the -t
+ option, then it will attempt to use tcpdump's dissector to decode each
+ packet that it processes. The dissector is presently not available, so
+ this option it normally turned off at compile time. The dissector
+ library will be released with tcpdump version 4.0.</DD>
+</DL>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="umltesting.html">Previous</A>
+<A HREF="nightly.html">Next</A>
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec.8.html b/doc/manpage.d/ipsec.8.html
new file mode 100644
index 000000000..ff9b7ca39
--- /dev/null
+++ b/doc/manpage.d/ipsec.8.html
@@ -0,0 +1,215 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC</TITLE>
+</HEAD><BODY>
+<H1>IPSEC</H1>
+Section: Maintenance Commands (8)<BR>Updated: 26 March 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec - invoke IPsec utilities
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+command [ argument ...]
+<P>
+<B>ipsec</B>
+
+<B>--help</B>
+
+<BR>
+
+<B>ipsec</B>
+
+<B>--version</B>
+
+<BR>
+
+<B>ipsec</B>
+
+<B>--versioncode</B>
+
+<BR>
+
+<B>ipsec</B>
+
+<B>--copyright</B>
+
+<BR>
+
+<B>ipsec</B>
+
+<B>--directory</B>
+
+<BR>
+
+<B>ipsec</B>
+
+<B>--confdir</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Ipsec</I>
+
+invokes any of several utilities involved in controlling the IPsec
+encryption/authentication system,
+running the specified
+<I>command</I>
+
+with the specified
+<I>argument</I>s
+
+as if it had been invoked directly.
+This largely eliminates possible name collisions with other software,
+and also permits some centralized services.
+<P>
+
+In particular,
+<I>ipsec</I>
+
+supplies the invoked
+<I>command</I>
+
+with a suitable PATH environment variable,
+and also provides IPSEC_DIR,
+IPSEC_CONFS, and IPSEC_VERSION environment variables,
+containing respectively
+the full pathname of the directory where the IPsec utilities are stored,
+the full pathname of the directory where the configuration files live,
+and the IPsec version number.
+<P>
+
+<B>ipsec --help</B>
+
+lists the available commands.
+Most have their own manual pages, e.g.
+<I><A HREF="ipsec_auto.8.html">ipsec_auto</A></I>(8)
+
+for
+<I>auto</I>.
+
+<P>
+
+<B>ipsec --version</B>
+
+outputs version information about Linux FreeS/WAN.
+A version code of the form ``U<I>xxx</I>/K<I>yyy</I>''
+indicates that the user-level utilities are version <I>xxx</I>
+but the kernel portion appears to be version <I>yyy</I>
+(this form is used only if the two disagree).
+<P>
+
+<B>ipsec --versioncode</B>
+
+outputs <I>just</I> the version code,
+with none of
+<B>--version</B>'s
+
+supporting information,
+for use by scripts.
+<P>
+
+<B>ipsec --copyright</B>
+
+supplies boring copyright details.
+<P>
+
+<B>ipsec --directory</B>
+
+reports where
+<I>ipsec</I>
+
+thinks the IPsec utilities are stored.
+<P>
+
+<B>ipsec --confdir</B>
+
+reports where
+<I>ipsec</I>
+
+thinks the IPsec configuration files are stored.
+<A NAME="lbAE">&nbsp;</A>
+<H2>FILES</H2>
+
+/usr/local/lib/ipsec<TT>&nbsp;&nbsp;&nbsp;</TT>usual utilities directory<BR>
+<A NAME="lbAF">&nbsp;</A>
+<H2>ENVIRONMENT</H2>
+
+<P>
+
+The following environment variables control where FreeS/WAN finds its
+components.
+The
+<B>ipsec</B>
+
+command sets them if they are not already set.
+<PRE>
+IPSEC_EXECDIR   directory containing published commands
+IPSEC_LIBDIR    directory containing internal executables
+IPSEC_SBINDIR   directory containing <B>ipsec</B> command
+IPSEC_CONFS     directory containing configuration files
+</PRE>
+
+<A NAME="lbAG">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+
+
+<A HREF="ipsec.conf.5.html">ipsec.conf</A>(5), <A HREF="ipsec.secrets.5.html">ipsec.secrets</A>(5),
+<A HREF="ipsec_auto.8.html">ipsec_auto</A>(8),
+<A HREF="ipsec_barf.8.html">ipsec_barf</A>(8),
+<A HREF="ipsec_setup.8.html">ipsec_setup</A>(8),
+<A HREF="ipsec_showdefaults.8.html">ipsec_showdefaults</A>(8),
+<A HREF="ipsec_showhostkey.8.html">ipsec_showhostkey</A>(8)
+
+
+<P>
+
+HTML documentation shipped with the release, starting with
+<I>doc/index.html</I>.
+
+<I>&lt;<A HREF="http://www.freeswan.org/doc.html">http://www.freeswan.org/doc.html</A>&gt;</I>
+
+may also be of use.
+<A NAME="lbAH">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for Linux FreeS/WAN
+&lt;<A HREF="http://www.freeswan.org">http://www.freeswan.org</A>&gt;
+by Henry Spencer.
+<A NAME="lbAI">&nbsp;</A>
+<H2>BUGS</H2>
+
+The provision of centralized services,
+while convenient,
+does compromise the original concept of making the utilities
+invocable directly as well as via
+<I>ipsec</I>.
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">FILES</A><DD>
+<DT><A HREF="#lbAF">ENVIRONMENT</A><DD>
+<DT><A HREF="#lbAG">SEE ALSO</A><DD>
+<DT><A HREF="#lbAH">HISTORY</A><DD>
+<DT><A HREF="#lbAI">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec.conf.5.html b/doc/manpage.d/ipsec.conf.5.html
new file mode 100644
index 000000000..36e0452ef
--- /dev/null
+++ b/doc/manpage.d/ipsec.conf.5.html
@@ -0,0 +1,1830 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC.CONF</TITLE>
+</HEAD><BODY>
+<H1>IPSEC.CONF</H1>
+Section: File Formats (5)<BR>Updated: 26 Nov 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec.conf - IPsec configuration and connections
+<A NAME="lbAC">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+The optional
+<I>ipsec.conf</I>
+
+file
+specifies most configuration and control information for the
+FreeS/WAN IPsec subsystem.
+(The major exception is secrets for authentication;
+see
+<I><A HREF="ipsec.secrets.5.html">ipsec.secrets</A></I>(5).)
+
+Its contents are not security-sensitive
+<I>unless</I>
+
+manual keying is being done for more than just testing,
+in which case the encryption/authentication keys in the
+descriptions for the manually-keyed connections are very sensitive
+(and those connection descriptions
+are probably best kept in a separate file,
+via the include facility described below).
+<P>
+
+The file is a text file, consisting of one or more
+<I>sections</I>.
+
+White space followed by
+<B>#</B>
+
+followed by anything to the end of the line
+is a comment and is ignored,
+as are empty lines which are not within a section.
+<P>
+
+A line which contains
+<B>include</B>
+
+and a file name, separated by white space,
+is replaced by the contents of that file,
+preceded and followed by empty lines.
+If the file name is not a full pathname,
+it is considered to be relative to the directory containing the
+including file.
+Such inclusions can be nested.
+Only a single filename may be supplied, and it may not contain white space,
+but it may include shell wildcards (see
+<I><A HREF="sh.1.html">sh</A></I>(1));
+
+for example:
+<P>
+
+<B>include</B>
+
+<B>ipsec.*.conf</B>
+
+<P>
+
+The intention of the include facility is mostly to permit keeping
+information on connections, or sets of connections,
+separate from the main configuration file.
+This permits such connection descriptions to be changed,
+copied to the other security gateways involved, etc.,
+without having to constantly extract them from the configuration
+file and then insert them back into it.
+Note also the
+<B>also</B>
+
+and
+<B>alsoflip</B>
+
+parameters (described below) which permit splitting a single logical section
+(e.g. a connection description) into several actual sections.
+<P>
+
+The first significant line of the file must specify the version
+of this specification that it conforms to:
+<P>
+
+<B>version 2</B>
+<P>
+
+A section
+begins with a line of the form:
+<P>
+
+<I>type</I>
+
+<I>name</I>
+
+<P>
+
+where
+<I>type</I>
+
+indicates what type of section follows, and
+<I>name</I>
+
+is an arbitrary name which distinguishes the section from others
+of the same type.
+(Names must start with a letter and may contain only
+letters, digits, periods, underscores, and hyphens.)
+All subsequent non-empty lines
+which begin with white space are part of the section;
+comments within a section must begin with white space too.
+There may be only one section of a given type with a given name.
+<P>
+
+Lines within the section are generally of the form
+<P>
+
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<I>parameter</I><B>=</B><I>value</I>
+<P>
+
+(note the mandatory preceding white space).
+There can be white space on either side of the
+<B>=</B>.
+
+Parameter names follow the same syntax as section names,
+and are specific to a section type.
+Unless otherwise explicitly specified,
+no parameter name may appear more than once in a section.
+<P>
+
+An empty
+<I>value</I>
+
+stands for the system default value (if any) of the parameter,
+i.e. it is roughly equivalent to omitting the parameter line entirely.
+A
+<I>value</I>
+
+may contain white space only if the entire
+<I>value</I>
+
+is enclosed in double quotes (<B>&quot;</B>);
+a
+<I>value</I>
+
+cannot itself contain a double quote,
+nor may it be continued across more than one line.
+<P>
+
+Numeric values are specified to be either an ``integer''
+(a sequence of digits) or a ``decimal number''
+(sequence of digits optionally followed by `.' and another sequence of digits).
+<P>
+
+There is currently one parameter which is available in any type of
+section:
+<DL COMPACT>
+<DT><B>also</B>
+
+<DD>
+the value is a section name;
+the parameters of that section are appended to this section,
+as if they had been written as part of it.
+The specified section must exist, must follow the current one,
+and must have the same section type.
+(Nesting is permitted,
+and there may be more than one
+<B>also</B>
+
+in a single section,
+although it is forbidden to append the same section more than once.)
+This allows, for example, keeping the encryption keys
+for a connection in a separate file
+from the rest of the description, by using both an
+<B>also</B>
+
+parameter and an
+<B>include</B>
+
+line.
+(Caution, see BUGS below for some restrictions.)
+<DT><B>alsoflip</B>
+
+<DD>
+can be used in a
+<B>conn</B>
+
+section.
+It acts like an
+<B>also</B>
+
+that flips the referenced section's entries left-for-right.
+</DL>
+<P>
+
+Parameter names beginning with
+<B>x-</B>
+
+(or
+<B>X-</B>,
+
+or
+<B>x_</B>,
+
+or
+<B>X_</B>)
+
+are reserved for user extensions and will never be assigned meanings
+by IPsec.
+Parameters with such names must still observe the syntax rules
+(limits on characters used in the name;
+no white space in a non-quoted value;
+no newlines or double quotes within the value).
+All other as-yet-unused parameter names are reserved for future IPsec
+improvements.
+<P>
+
+A section with name
+<B>%default</B>
+
+specifies defaults for sections of the same type.
+For each parameter in it,
+any section of that type which does not have a parameter of the same name
+gets a copy of the one from the
+<B>%default</B>
+
+section.
+There may be multiple
+<B>%default</B>
+
+sections of a given type,
+but only one default may be supplied for any specific parameter name,
+and all
+<B>%default</B>
+
+sections of a given type must precede all non-<B>%default</B>
+
+sections of that type.
+<B>%default</B>
+
+sections may not contain
+<B>also</B>
+
+or
+<B>alsoflip</B>
+
+parameters.
+<P>
+
+Currently there are two types of section:
+a
+<B>config</B>
+
+section specifies general configuration information for IPsec,
+while a
+<B>conn</B>
+
+section specifies an IPsec connection.
+<A NAME="lbAD">&nbsp;</A>
+<H2>CONN SECTIONS</H2>
+
+A
+<B>conn</B>
+
+section contains a
+<I>connection specification</I>,
+
+defining a network connection to be made using IPsec.
+The name given is arbitrary, and is used to identify the connection to
+<I><A HREF="ipsec_auto.8.html">ipsec_auto</A></I>(8)
+
+and
+<I><A HREF="ipsec_manual.8.html">ipsec_manual</A></I>(8).
+
+Here's a simple example:
+<P>
+
+
+<PRE>
+<B>
+conn snt
+ left=10.11.11.1
+ leftsubnet=10.0.1.0/24
+ leftnexthop=172.16.55.66
+ right=192.168.22.1
+ rightsubnet=10.0.2.0/24
+ rightnexthop=172.16.88.99
+ keyingtries=%forever
+</B></PRE>
+
+<P>
+
+A note on terminology...
+In automatic keying, there are two kinds of communications going on:
+transmission of user IP packets, and gateway-to-gateway negotiations for
+keying, rekeying, and general control.
+The data path (a set of ``IPsec SAs'') used for user packets is herein
+referred to as the ``connection'';
+the path used for negotiations (built with ``ISAKMP SAs'') is referred to as
+the ``keying channel''.
+<P>
+
+To avoid trivial editing of the configuration file to suit it to each system
+involved in a connection,
+connection specifications are written in terms of
+<I>left</I>
+
+and
+<I>right</I>
+
+participants,
+rather than in terms of local and remote.
+Which participant is considered
+<I>left</I>
+
+or
+<I>right</I>
+
+is arbitrary;
+IPsec figures out which one it is being run on based on internal information.
+This permits using identical connection specifications on both ends.
+There are cases where there is no symmetry; a good convention is to
+use
+<I>left</I>
+
+for the local side and
+<I>right</I>
+
+for the remote side (the first letters are a good mnemonic).
+<P>
+
+Many of the parameters relate to one participant or the other;
+only the ones for
+<I>left</I>
+
+are listed here, but every parameter whose name begins with
+<B>left</B>
+
+has a
+<B>right</B>
+
+counterpart,
+whose description is the same but with
+<B>left</B>
+
+and
+<B>right</B>
+
+reversed.
+<P>
+
+Parameters are optional unless marked ``(required)'';
+a parameter required for manual keying need not be included for
+a connection which will use only automatic keying, and vice versa.
+<A NAME="lbAE">&nbsp;</A>
+<H3>CONN PARAMETERS:  GENERAL</H3>
+
+The following parameters are relevant to both automatic and manual keying.
+Unless otherwise noted,
+for a connection to work,
+in general it is necessary for the two ends to agree exactly
+on the values of these parameters.
+<DL COMPACT>
+<DT><B>type</B>
+
+<DD>
+the type of the connection; currently the accepted values
+are
+<B>tunnel</B>
+
+(the default)
+signifying a host-to-host, host-to-subnet, or subnet-to-subnet tunnel;
+<B>transport</B>,
+
+signifying host-to-host transport mode;
+<B>passthrough</B>,
+
+signifying that no IPsec processing should be done at all;
+<B>drop</B>,
+
+signifying that packets should be discarded; and
+<B>reject</B>,
+
+signifying that packets should be discarded and a diagnostic ICMP returned.
+<DT><B>left</B>
+
+<DD>
+(required)
+the IP address of the left participant's public-network interface,
+in any form accepted by
+<I><A HREF="ipsec_ttoaddr.3.html">ipsec_ttoaddr</A></I>(3)
+
+or one of several magic values.
+If it is
+<B>%defaultroute</B>,
+
+and
+the
+<B>config</B>
+
+<B>setup</B>
+
+section's,
+<B>interfaces</B>
+
+specification contains
+<B>%defaultroute,</B>
+
+<B>left</B>
+
+will be filled in automatically with the local address
+of the default-route interface (as determined at IPsec startup time);
+this also overrides any value supplied for
+<B>leftnexthop</B>.
+
+(Either
+<B>left</B>
+
+or
+<B>right</B>
+
+may be
+<B>%defaultroute</B>,
+
+but not both.)
+The value
+<B>%any</B>
+
+signifies an address to be filled in (by automatic keying) during
+negotiation.
+The value
+<B>%opportunistic</B>
+
+signifies that both
+<B>left</B>
+
+and
+<B>leftnexthop</B>
+
+are to be filled in (by automatic keying) from DNS data for
+<B>left</B>'s
+
+client.
+The values
+<B>%group</B>
+
+and
+<B>%opportunisticgroup</B>
+
+makes this a policy group conn: one that will be instantiated
+into a regular or opportunistic conn for each CIDR block listed in the
+policy group file with the same name as the conn.
+<DT><B>leftsubnet</B>
+
+<DD>
+private subnet behind the left participant, expressed as
+<I>network</I><B>/</B><I>netmask</I>
+(actually, any form acceptable to
+<I><A HREF="ipsec_ttosubnet.3.html">ipsec_ttosubnet</A></I>(3));
+
+if omitted, essentially assumed to be <I>left</I><B>/32</B>,
+signifying that the left end of the connection goes to the left participant only
+<DT><B>leftnexthop</B>
+
+<DD>
+next-hop gateway IP address for the left participant's connection
+to the public network;
+defaults to
+<B>%direct</B>
+
+(meaning
+<I>right</I>).
+
+If the value is to be overridden by the
+<B>left=%defaultroute</B>
+
+method (see above),
+an explicit value must
+<I>not</I>
+
+be given.
+If that method is not being used,
+but
+<B>leftnexthop</B>
+
+is
+<B>%defaultroute</B>,
+
+and
+<B>interfaces=%defaultroute</B>
+
+is used in the
+<B>config</B>
+
+<B>setup</B>
+
+section,
+the next-hop gateway address of the default-route interface
+will be used.
+The magic value
+<B>%direct</B>
+
+signifies a value to be filled in (by automatic keying)
+with the peer's address.
+Relevant only locally, other end need not agree on it.
+<DT><B>leftupdown</B>
+
+<DD>
+what ``updown'' script to run to adjust routing and/or firewalling
+when the status of the connection
+changes (default
+<B>ipsec _updown</B>).
+
+May include positional parameters separated by white space
+(although this requires enclosing the whole string in quotes);
+including shell metacharacters is unwise.
+See
+<I><A HREF="ipsec_pluto.8.html">ipsec_pluto</A></I>(8)
+
+for details.
+Relevant only locally, other end need not agree on it.
+<DT><B>leftfirewall</B>
+
+<DD>
+whether the left participant is doing forwarding-firewalling
+(including masquerading) for traffic from <I>leftsubnet</I>,
+which should be turned off (for traffic to the other subnet)
+once the connection is established;
+acceptable values are
+<B>yes</B>
+
+and (the default)
+<B>no</B>.
+
+May not be used in the same connection description with
+<B>leftupdown</B>.
+
+Implemented as a parameter to the default
+<I>updown</I>
+
+script.
+See notes below.
+Relevant only locally, other end need not agree on it.
+</DL>
+<P>
+
+If one or both security gateways are doing forwarding firewalling
+(possibly including masquerading),
+and this is specified using the firewall parameters,
+tunnels established with IPsec are exempted from it
+so that packets can flow unchanged through the tunnels.
+(This means that all subnets connected in this manner must have
+distinct, non-overlapping subnet address blocks.)
+This is done by the default
+<I>updown</I>
+
+script (see
+<I><A HREF="ipsec_pluto.8.html">ipsec_pluto</A></I>(8)).
+
+<P>
+
+The implementation of this makes certain assumptions about firewall setup,
+notably the use of the old
+<I>ipfwadm</I>
+
+interface to the firewall.
+In situations calling for more control,
+it may be preferable for the user to supply his own
+<I>updown</I>
+
+script,
+which makes the appropriate adjustments for his system.
+<A NAME="lbAF">&nbsp;</A>
+<H3>CONN PARAMETERS:  AUTOMATIC KEYING</H3>
+
+The following parameters are relevant only to automatic keying,
+and are ignored in manual keying.
+Unless otherwise noted,
+for a connection to work,
+in general it is necessary for the two ends to agree exactly
+on the values of these parameters.
+<DL COMPACT>
+<DT><B>keyexchange</B>
+
+<DD>
+method of key exchange;
+the default and currently the only accepted value is
+<B>ike</B>
+
+<DT><B>auto</B>
+
+<DD>
+what operation, if any, should be done automatically at IPsec startup;
+currently-accepted values are
+<B>add</B>
+
+(signifying an
+<B>ipsec auto</B>
+
+<B>--add</B>),
+
+<B>route</B>
+
+(signifying that plus an
+<B>ipsec auto</B>
+
+<B>--route</B>),
+
+<B>start</B>
+
+(signifying that plus an
+<B>ipsec auto</B>
+
+<B>--up</B>),
+
+<B>manual</B>
+
+(signifying an
+<B>ipsec</B>
+
+<B>manual</B>
+
+<B>--up</B>),
+
+and
+<B>ignore</B>
+
+(also the default) (signifying no automatic startup operation).
+See the
+<B>config</B>
+
+<B>setup</B>
+
+discussion below.
+Relevant only locally, other end need not agree on it
+(but in general, for an intended-to-be-permanent connection,
+both ends should use
+<B>auto=start</B>
+
+to ensure that any reboot causes immediate renegotiation).
+<DT><B>auth</B>
+
+<DD>
+whether authentication should be done as part of
+ESP encryption, or separately using the AH protocol;
+acceptable values are
+<B>esp</B>
+
+(the default) and
+<B>ah</B>.
+
+<DT><B>authby</B>
+
+<DD>
+how the two security gateways should authenticate each other;
+acceptable values are
+<B>secret</B>
+
+for shared secrets,
+<B>rsasig</B>
+
+for RSA digital signatures (the default),
+<B>secret|rsasig</B>
+
+for either, and
+<B>never</B>
+
+if negotiation is never to be attempted or accepted (useful for shunt-only conns).
+Digital signatures are superior in every way to shared secrets.
+<DT><B>leftid</B>
+
+<DD>
+how
+the left participant
+should be identified for authentication;
+defaults to
+<B>left</B>.
+
+Can be an IP address (in any
+<I><A HREF="ipsec_ttoaddr.3.html">ipsec_ttoaddr</A></I>(3)
+
+syntax)
+or a fully-qualified domain name preceded by
+<B>@</B>
+
+(which is used as a literal string and not resolved).
+The magic value
+<B>%myid</B>
+
+stands for the current setting of <I>myid</I>.
+This is set in <B>config setup</B> or by <I><A HREF="ipsec_whack.8.html">ipsec_whack</A></I>(8)), or, if not set,
+it is the IP address in <B>%defaultroute</B> (if that is supported by a TXT record in its reverse domain), or otherwise
+it is the system's hostname (if that is supported by a TXT record in its forward domain), or otherwise it is undefined.
+<DT><B>leftrsasigkey</B>
+
+<DD>
+the left participant's
+public key for RSA signature authentication,
+in RFC 2537 format using
+<I><A HREF="ipsec_ttodata.3.html">ipsec_ttodata</A></I>(3)
+
+encoding.
+The magic value
+<B>%none</B>
+
+means the same as not specifying a value (useful to override a default).
+The value
+<B>%dnsondemand</B>
+
+(the default)
+means the key is to be fetched from DNS at the time it is needed.
+The value
+<B>%dnsonload</B>
+
+means the key is to be fetched from DNS at the time
+the connection description is read from
+<I>ipsec.conf</I>;
+
+currently this will be treated as
+<B>%none</B>
+
+if
+<B>right=%any</B>
+
+or
+<B>right=%opportunistic</B>.
+
+The value
+<B>%dns</B>
+
+is currently treated as
+<B>%dnsonload</B>
+
+but will change to
+<B>%dnsondemand</B>
+
+in the future.
+The identity used for the left participant
+must be a specific host, not
+<B>%any</B>
+
+or another magic value.
+<B>Caution:</B>
+
+if two connection descriptions
+specify different public keys for the same
+<B>leftid</B>,
+
+confusion and madness will ensue.
+<DT><B>leftrsasigkey2</B>
+
+<DD>
+if present, a second public key.
+Either key can authenticate the signature, allowing for key rollover.
+<DT><B>pfs</B>
+
+<DD>
+whether Perfect Forward Secrecy of keys is desired on the connection's
+keying channel
+(with PFS, penetration of the key-exchange protocol
+does not compromise keys negotiated earlier);
+acceptable values are
+<B>yes</B>
+
+(the default)
+and
+<B>no</B>.
+
+<DT><B>keylife</B>
+
+<DD>
+how long a particular instance of a connection
+(a set of encryption/authentication keys for user packets) should last,
+from successful negotiation to expiry;
+acceptable values are an integer optionally followed by
+<B>s</B>
+
+(a time in seconds)
+or a decimal number followed by
+<B>m</B>,
+
+<B>h</B>,
+
+or
+<B>d</B>
+
+(a time
+in minutes, hours, or days respectively)
+(default
+<B>8.0h</B>,
+
+maximum
+<B>24h</B>).
+
+Normally, the connection is renegotiated (via the keying channel)
+before it expires.
+The two ends need not exactly agree on
+<B>keylife</B>,
+
+although if they do not,
+there will be some clutter of superseded connections on the end
+which thinks the lifetime is longer.
+<DT><B>rekey</B>
+
+<DD>
+whether a connection should be renegotiated when it is about to expire;
+acceptable values are
+<B>yes</B>
+
+(the default)
+and
+<B>no</B>.
+
+The two ends need not agree,
+but while a value of
+<B>no</B>
+
+prevents Pluto from requesting renegotiation,
+it does not prevent responding to renegotiation requested from the other end,
+so
+<B>no</B>
+
+will be largely ineffective unless both ends agree on it.
+<DT><B>rekeymargin</B>
+
+<DD>
+how long before connection expiry or keying-channel expiry
+should attempts to
+negotiate a replacement
+begin; acceptable values as for
+<B>keylife</B>
+
+(default
+<B>9m</B>).
+
+Relevant only locally, other end need not agree on it.
+<DT><B>rekeyfuzz</B>
+
+<DD>
+maximum percentage by which
+<B>rekeymargin</B>
+
+should be randomly increased to randomize rekeying intervals
+(important for hosts with many connections);
+acceptable values are an integer,
+which may exceed 100,
+followed by a `%'
+(default set by
+<I><A HREF="ipsec_pluto.8.html">ipsec_pluto</A></I>(8),
+
+currently
+<B>100%</B>).
+
+The value of
+<B>rekeymargin</B>,
+
+after this random increase,
+must not exceed
+<B>keylife</B>.
+
+The value
+<B>0%</B>
+
+will suppress time randomization.
+Relevant only locally, other end need not agree on it.
+<DT><B>keyingtries</B>
+
+<DD>
+how many attempts (a whole number or <B>%forever</B>) should be made to
+negotiate a connection, or a replacement for one, before giving up
+(default
+<B>%forever</B>).
+
+The value <B>%forever</B>
+means ``never give up'' (obsolete: this can be written <B>0</B>).
+Relevant only locally, other end need not agree on it.
+<DT><B>ikelifetime</B>
+
+<DD>
+how long the keying channel of a connection (buzzphrase:  ``ISAKMP SA'')
+should last before being renegotiated;
+acceptable values as for
+<B>keylife</B>
+
+(default set by
+<I><A HREF="ipsec_pluto.8.html">ipsec_pluto</A></I>(8),
+
+currently
+<B>1h</B>,
+
+maximum
+<B>8h</B>).
+
+The two-ends-disagree case is similar to that of
+<B>keylife</B>.
+
+<DT><B>compress</B>
+
+<DD>
+whether IPComp compression of content is proposed on the connection
+(link-level compression does not work on encrypted data,
+so to be effective, compression must be done <I>before</I> encryption);
+acceptable values are
+<B>yes</B>
+
+and
+<B>no</B>
+
+(the default).
+The two ends need not agree.
+A value of
+<B>yes</B>
+
+causes IPsec to propose both compressed and uncompressed,
+and prefer compressed.
+A value of
+<B>no</B>
+
+prevents IPsec from proposing compression;
+a proposal to compress will still be accepted.
+<DT><B>disablearrivalcheck</B>
+
+<DD>
+whether KLIPS's normal tunnel-exit check
+(that a packet emerging from a tunnel has plausible addresses in its header)
+should be disabled;
+acceptable values are
+<B>yes</B>
+
+and
+<B>no</B>
+
+(the default).
+Tunnel-exit checks improve security and do not break any normal configuration.
+Relevant only locally, other end need not agree on it.
+<DT><B>failureshunt</B>
+
+<DD>
+what to do with packets when negotiation fails.
+The default is
+<B>none</B>:
+
+no shunt;
+<B>passthrough</B>,
+
+<B>drop</B>,
+
+and
+<B>reject</B>
+
+have the obvious meanings.
+</DL>
+<A NAME="lbAG">&nbsp;</A>
+<H3>CONN PARAMETERS:  MANUAL KEYING</H3>
+
+The following parameters are relevant only to manual keying,
+and are ignored in automatic keying.
+Unless otherwise noted,
+for a connection to work,
+in general it is necessary for the two ends to agree exactly
+on the values of these parameters.
+A manually-keyed
+connection must specify at least one of AH or ESP.
+<DL COMPACT>
+<DT><B>spi</B>
+
+<DD>
+(this or
+<B>spibase</B>
+
+required for manual keying)
+the SPI number to be used for the connection (see
+<I><A HREF="ipsec_manual.8.html">ipsec_manual</A></I>(8));
+
+must be of the form <B>0x</B><I>hex</I><B></B>,
+where
+<I>hex</I>
+
+is one or more hexadecimal digits
+(note, it will generally be necessary to make
+<I>spi</I>
+
+at least
+<B>0x100</B>
+
+to be acceptable to KLIPS,
+and use of SPIs in the range
+<B>0x100</B>-<B>0xfff</B>
+
+is recommended)
+<DT><B>spibase</B>
+
+<DD>
+(this or
+<B>spi</B>
+
+required for manual keying)
+the base number for the SPIs to be used for the connection (see
+<I><A HREF="ipsec_manual.8.html">ipsec_manual</A></I>(8));
+
+must be of the form <B>0x</B><I>hex</I><B>0</B>,
+where
+<I>hex</I>
+
+is one or more hexadecimal digits
+(note, it will generally be necessary to make
+<I>spibase</I>
+
+at least
+<B>0x100</B>
+
+for the resulting SPIs
+to be acceptable to KLIPS,
+and use of numbers in the range
+<B>0x100</B>-<B>0xff0</B>
+
+is recommended)
+<DT><B>esp</B>
+
+<DD>
+ESP encryption/authentication algorithm to be used
+for the connection, e.g.
+<B>3des-md5-96</B>
+
+(must be suitable as a value of
+<I><A HREF="ipsec_spi.8.html">ipsec_spi</A></I>(8)'s
+
+<B>--esp</B>
+
+option);
+default is not to use ESP
+<DT><B>espenckey</B>
+
+<DD>
+ESP encryption key
+(must be suitable as a value of
+<I><A HREF="ipsec_spi.8.html">ipsec_spi</A></I>(8)'s
+
+<B>--enckey</B>
+
+option)
+(may be specified separately for each direction using
+<B>leftespenckey</B>
+
+(leftward SA)
+and
+<B>rightespenckey</B>
+
+parameters)
+<DT><B>espauthkey</B>
+
+<DD>
+ESP authentication key
+(must be suitable as a value of
+<I><A HREF="ipsec_spi.8.html">ipsec_spi</A></I>(8)'s
+
+<B>--authkey</B>
+
+option)
+(may be specified separately for each direction using
+<B>leftespauthkey</B>
+
+(leftward SA)
+and
+<B>rightespauthkey</B>
+
+parameters)
+<DT><B>espreplay_window</B>
+
+<DD>
+ESP replay-window setting,
+an integer from
+<B>0</B>
+
+(the
+<I>ipsec_manual</I>
+
+default, which turns off replay protection) to
+<B>64</B>;
+
+relevant only if ESP authentication is being used
+<DT><B>leftespspi</B>
+
+<DD>
+SPI to be used for the leftward ESP SA, overriding
+automatic assignment using
+<B>spi</B>
+
+or
+<B>spibase</B>;
+
+typically a hexadecimal number beginning with
+<B>0x</B>
+
+<DT><B>ah</B>
+
+<DD>
+AH authentication algorithm to be used
+for the connection, e.g.
+<B>hmac-md5-96</B>
+
+(must be suitable as a value of
+<I><A HREF="ipsec_spi.8.html">ipsec_spi</A></I>(8)'s
+
+<B>--ah</B>
+
+option);
+default is not to use AH
+<DT><B>ahkey</B>
+
+<DD>
+(required if
+<B>ah</B>
+
+is present) AH authentication key
+(must be suitable as a value of
+<I><A HREF="ipsec_spi.8.html">ipsec_spi</A></I>(8)'s
+
+<B>--authkey</B>
+
+option)
+(may be specified separately for each direction using
+<B>leftahkey</B>
+
+(leftward SA)
+and
+<B>rightahkey</B>
+
+parameters)
+<DT><B>ahreplay_window</B>
+
+<DD>
+AH replay-window setting,
+an integer from
+<B>0</B>
+
+(the
+<I>ipsec_manual</I>
+
+default, which turns off replay protection) to
+<B>64</B>
+
+<DT><B>leftahspi</B>
+
+<DD>
+SPI to be used for the leftward AH SA, overriding
+automatic assignment using
+<B>spi</B>
+
+or
+<B>spibase</B>;
+
+typically a hexadecimal number beginning with
+<B>0x</B>
+
+</DL>
+<A NAME="lbAH">&nbsp;</A>
+<H2>CONFIG SECTIONS</H2>
+
+At present, the only
+<B>config</B>
+
+section known to the IPsec software is the one named
+<B>setup</B>,
+
+which contains information used when the software is being started
+(see
+<I><A HREF="ipsec_setup.8.html">ipsec_setup</A></I>(8)).
+
+Here's an example:
+<P>
+
+
+<PRE>
+<B>
+config setup
+ interfaces=&quot;ipsec0=eth1 ipsec1=ppp0&quot;
+ klipsdebug=none
+ plutodebug=all
+ manualstart=
+</B></PRE>
+
+<P>
+
+Parameters are optional unless marked ``(required)''.
+The currently-accepted
+<I>parameter</I>
+
+names in a
+<B>config</B>
+
+<B>setup</B>
+
+section are:
+<DL COMPACT>
+<DT><B>myid</B>
+
+<DD>
+the identity to be used for
+<B>%myid</B>.
+
+<B>%myid</B>
+
+is used in the implicit policy group conns and can be used as
+an identity in explicit conns.
+If unspecified,
+<B>%myid</B>
+
+is set to the IP address in <B>%defaultroute</B> (if that is supported by a TXT record in its reverse domain), or otherwise
+the system's hostname (if that is supported by a TXT record in its forward domain), or otherwise it is undefined.
+An explicit value generally starts with ``<B>@</B>''.
+<DT><B>interfaces</B>
+
+<DD>
+virtual and physical interfaces for IPsec to use:
+a single
+<I>virtual</I><B>=</B><I>physical</I> pair, a (quoted!) list of pairs separated
+by white space, or
+<B>%none</B>.
+
+One of the pairs may be written as
+<B>%defaultroute</B>,
+
+which means: find the interface <I>d</I> that the default route points to,
+and then act as if the value was ``<B>ipsec0=</B><I>d</I>''.
+<B>%defaultroute</B>
+
+is the default;
+<B>%none</B>
+
+must be used to denote no interfaces.
+If
+<B>%defaultroute</B>
+
+is used (implicitly or explicitly)
+information about the default route and its interface is noted for
+use by
+<I><A HREF="ipsec_manual.8.html">ipsec_manual</A></I>(8)
+
+and
+<I><A HREF="ipsec_auto.8.html">ipsec_auto</A></I>(8).)
+
+<DT><B>forwardcontrol</B>
+
+<DD>
+whether
+<I>setup</I>
+
+should turn IP forwarding on
+(if it's not already on) as IPsec is started,
+and turn it off again (if it was off) as IPsec is stopped;
+acceptable values are
+<B>yes</B>
+
+and (the default)
+<B>no</B>.
+
+For this to have full effect, forwarding must be
+disabled before the hardware interfaces are brought
+up (e.g.,
+<B>net.ipv4.ip_forward&nbsp;=&nbsp;0</B>
+
+in Red Hat 6.x
+<I>/etc/sysctl.conf</I>),
+
+because IPsec doesn't get control early enough to do that.
+<DT><B>rp_filter</B>
+
+<DD>
+whether and how
+<I>setup</I>
+
+should adjust the reverse path filtering mechanism for the
+physical devices to be used.
+Values are <B>%unchanged</B> (to leave it alone)
+or <B>0</B>, <B>1</B>, <B>2</B> (values to set it to).
+<I>/proc/sys/net/ipv4/conf/PHYS/rp_filter</I>
+is badly documented; it must be <B>0</B> in many cases
+for ipsec to function.
+The default value for the parameter is <B>0</B>.
+<DT><B>syslog</B>
+
+<DD>
+the
+<I><A HREF="syslog.2.html">syslog</A></I>(2)
+
+``facility'' name and priority to use for
+startup/shutdown log messages,
+default
+<B>daemon.error</B>.
+
+<DT><B>klipsdebug</B>
+
+<DD>
+how much KLIPS debugging output should be logged.
+An empty value,
+or the magic value
+<B>none</B>,
+
+means no debugging output (the default).
+The magic value
+<B>all</B>
+
+means full output.
+Otherwise only the specified types of output
+(a quoted list, names separated by white space) are enabled;
+for details on available debugging types, see
+<I><A HREF="ipsec_klipsdebug.8.html">ipsec_klipsdebug</A></I>(8).
+
+<DT><B>plutodebug</B>
+
+<DD>
+how much Pluto debugging output should be logged.
+An empty value,
+or the magic value
+<B>none</B>,
+
+means no debugging output (the default).
+The magic value
+<B>all</B>
+
+means full output.
+Otherwise only the specified types of output
+(a quoted list, names without the
+<B>--debug-</B>
+
+prefix,
+separated by white space) are enabled;
+for details on available debugging types, see
+<I><A HREF="ipsec_pluto.8.html">ipsec_pluto</A></I>(8).
+
+<DT><B>plutoopts</B>
+
+<DD>
+additional options to pass to pluto upon startup. See
+<I><A HREF="ipsec_pluto.8.html">ipsec_pluto</A></I>(8).
+
+<DT><B>plutostderrlog</B>
+
+<DD>
+do not use syslog, but rather log to stderr, and direct stderr to the
+argument file.
+<DT><B>dumpdir</B>
+
+<DD>
+in what directory should things started by
+<I>setup</I>
+
+(notably the Pluto daemon) be allowed to
+dump core?
+The empty value (the default) means they are not
+allowed to.
+<DT><B>manualstart</B>
+
+<DD>
+which manually-keyed connections to set up at startup
+(empty, a name, or a quoted list of names separated by white space);
+see
+<I><A HREF="ipsec_manual.8.html">ipsec_manual</A></I>(8).
+
+Default is none.
+<DT><B>pluto</B>
+
+<DD>
+whether to start Pluto or not;
+Values are
+<B>yes</B>
+
+(the default)
+or
+<B>no</B>
+
+(useful only in special circumstances).
+<DT><B>plutowait</B>
+
+<DD>
+should Pluto wait for each
+negotiation attempt that is part of startup to
+finish before proceeding with the next?
+Values are
+<B>yes</B>
+
+or
+<B>no</B>
+
+(the default).
+<DT><B>prepluto</B>
+
+<DD>
+shell command to run before starting Pluto
+(e.g., to decrypt an encrypted copy of the
+<I>ipsec.secrets</I>
+
+file).
+It's run in a very simple way;
+complexities like I/O redirection are best hidden within a script.
+Any output is redirected for logging,
+so running interactive commands is difficult unless they use
+<I>/dev/tty</I>
+
+or equivalent for their interaction.
+Default is none.
+<DT><B>postpluto</B>
+
+<DD>
+shell command to run after starting Pluto
+(e.g., to remove a decrypted copy of the
+<I>ipsec.secrets</I>
+
+file).
+It's run in a very simple way;
+complexities like I/O redirection are best hidden within a script.
+Any output is redirected for logging,
+so running interactive commands is difficult unless they use
+<I>/dev/tty</I>
+
+or equivalent for their interaction.
+Default is none.
+<DT><B>fragicmp</B>
+
+<DD>
+whether a tunnel's need to fragment a packet should be reported
+back with an ICMP message,
+in an attempt to make the sender lower his PMTU estimate;
+acceptable values are
+<B>yes</B>
+
+(the default)
+and
+<B>no</B>.
+
+<DT><B>hidetos</B>
+
+<DD>
+whether a tunnel packet's TOS field should be set to
+<B>0</B>
+
+rather than copied from the user packet inside;
+acceptable values are
+<B>yes</B>
+
+(the default)
+and
+<B>no</B>.
+
+<DT><B>uniqueids</B>
+
+<DD>
+whether a particular participant ID should be kept unique,
+with any new (automatically keyed)
+connection using an ID from a different IP address
+deemed to replace all old ones using that ID;
+acceptable values are
+<B>yes</B>
+
+(the default)
+and
+<B>no</B>.
+
+Participant IDs normally <I>are</I> unique,
+so a new (automatically-keyed) connection using the same ID is
+almost invariably intended to replace an old one.
+<DT><B>overridemtu</B>
+
+<DD>
+value that the MTU of the ipsec<I>n</I> interface(s) should be set to,
+overriding IPsec's (large) default.
+This parameter is needed only in special situations.
+</DL>
+<A NAME="lbAI">&nbsp;</A>
+<H2>IMPLICIT CONNS</H2>
+
+<P>
+
+The system automatically defines several conns to implement
+default policy groups.  Each can be overridden by explicitly
+defining a new conn with the same name.  If the new conn has <B>auto=ignore</B>,
+the definition is suppressed.
+<P>
+
+Here are the automatically supplied definitions.
+<P>
+
+
+<PRE>
+<B>
+conn clear
+ type=passthrough
+ authby=never
+ left=%defaultroute
+ right=%group
+ auto=route
+
+conn clear-or-private
+ type=passthrough
+ left=%defaultroute
+ leftid=%myid
+ right=%opportunisticgroup
+ failureshunt=passthrough
+ keyingtries=3
+ ikelifetime=1h
+ keylife=1h
+ rekey=no
+ auto=route
+
+conn private-or-clear
+ type=tunnel
+ left=%defaultroute
+ leftid=%myid
+ right=%opportunisticgroup
+ failureshunt=passthrough
+ keyingtries=3
+ ikelifetime=1h
+ keylife=1h
+ rekey=no
+ auto=route
+
+conn private
+ type=tunnel
+ left=%defaultroute
+ leftid=%myid
+ right=%opportunisticgroup
+ failureshunt=drop
+ keyingtries=3
+ ikelifetime=1h
+ keylife=1h
+ rekey=no
+ auto=route
+
+conn block
+ type=reject
+ authby=never
+ left=%defaultroute
+ right=%group
+ auto=route
+
+# default policy
+conn packetdefault
+ type=tunnel
+ left=%defaultroute
+ leftid=%myid
+ left=0.0.0.0/0
+ right=%opportunistic
+ failureshunt=passthrough
+ keyingtries=3
+ ikelifetime=1h
+ keylife=1h
+ rekey=no
+ auto=route
+</B></PRE>
+
+<P>
+
+These conns are <I>not</I> affected by anything in <B>conn %default</B>.
+They will only work if <B>%defaultroute</B> works.
+The <B>leftid</B> will be the interfaces IP address; this
+requires that reverse DNS records be set up properly.
+<P>
+
+The implicit conns are defined after all others.  It is
+appropriate and reasonable to use <B>also=private-or-clear</B>
+(for example) in any other opportunistic conn.
+<A NAME="lbAJ">&nbsp;</A>
+<H2>POLICY GROUP FILES</H2>
+
+<P>
+
+The optional files under 
+<I>/etc/ipsec.d/policy</I>,
+
+including
+<PRE>
+
+/etc/ipsec.d/policies/clear
+/etc/ipsec.d/policies/clear-or-private
+/etc/ipsec.d/policies/private-or-clear
+/etc/ipsec.d/policies/private
+/etc/ipsec.d/policies/block
+
+</PRE>
+
+may contain policy group configuration information to 
+supplement 
+<I>ipsec.conf</I>.
+
+Their contents are not security-sensitive.
+<P>
+
+These files are text files.
+Each consists of a list of CIDR blocks, one per line.
+White space followed by # followed by anything to the end of the line
+is a comment and is ignored, as are empty lines.
+<P>
+
+A connection in
+<I>/etc/ipsec.conf</I>
+
+which has
+<B>right=%group</B>
+
+or 
+<B>right=%opportunisticgroup</B>
+
+is a policy group connection.
+When a policy group file of the same name is loaded, with
+<P>
+
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<B>ipsec auto --rereadgroups</B> 
+<P>
+
+or at system start, the connection is instantiated such that each
+CIDR block serves as an instance's 
+<B>right</B>
+
+value. The system treats the
+resulting instances as normal connections.
+<P>
+
+For example, given a suitable connection definition 
+<B>private</B>,
+
+and the file
+<I>/etc/ipsec.d/policy/private </I>
+
+with an entry 192.0.2.3,
+the system creates a connection instance 
+<B>private#192.0.2.3.</B>
+
+This connection inherits all details from 
+<B>private</B>,
+
+except that its right client is 192.0.2.3.
+<A NAME="lbAK">&nbsp;</A>
+<H2>DEFAULT POLICY GROUPS</H2>
+
+<P>
+
+The standard FreeS/WAN install includes several policy groups
+which provide a way of classifying possible peers into IPsec security classes:
+<B>private</B>
+
+(talk encrypted only),
+<B>private-or-clear</B>
+
+(prefer encryption),
+<B>clear-or-private</B>
+
+(respond to requests for encryption), 
+<B>clear</B>
+
+and
+<B>block</B>.
+
+Implicit policy groups apply to the local host only,
+and are implemented by the
+<B>IMPLICIT CONNECTIONS </B>
+
+described above.
+<A NAME="lbAL">&nbsp;</A>
+<H2>CHOOSING A CONNECTION</H2>
+
+<P>
+
+When choosing a connection to apply to an outbound packet caught with a 
+<B>%trap,</B>
+
+the system prefers the one with the most specific eroute that
+includes the packet's source and destination IP addresses.
+Source subnets are examined before destination subnets.
+For initiating, only routed connections are considered. For responding,
+unrouted but added connections are considered.
+<P>
+
+When choosing a connection to use to respond to a negotiation which
+doesn't match an ordinary conn, an opportunistic connection
+may be instantiated. Eventually, its instance will be /32 -&gt; /32, but
+for earlier stages of the negotiation, there will not be enough
+information about the client subnets to complete the instantiation.
+<A NAME="lbAM">&nbsp;</A>
+<H2>FILES</H2>
+
+<PRE>
+/etc/ipsec.conf
+/etc/ipsec.d/policies/clear
+/etc/ipsec.d/policies/clear-or-private
+/etc/ipsec.d/policies/private-or-clear
+/etc/ipsec.d/policies/private
+/etc/ipsec.d/policies/block
+</PRE>
+
+<A NAME="lbAN">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_ttoaddr.8.html">ipsec_ttoaddr</A>(8), <A HREF="ipsec_auto.8.html">ipsec_auto</A>(8), <A HREF="ipsec_manual.8.html">ipsec_manual</A>(8), <A HREF="ipsec_rsasigkey.8.html">ipsec_rsasigkey</A>(8)
+<A NAME="lbAO">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Designed for the FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org">http://www.freeswan.org</A>&gt;
+by Henry Spencer.
+<A NAME="lbAP">&nbsp;</A>
+<H2>BUGS</H2>
+
+<P>
+
+When
+<B>type</B>
+
+or 
+<B>failureshunt</B>
+
+is set to
+<B>drop</B>
+
+or
+<B>reject,</B>
+
+FreeS/WAN blocks outbound packets using eroutes, but assumes inbound
+blocking is handled by the firewall. FreeS/WAN offers firewall hooks 
+via an ``updown'' script.  However, the default 
+<B>ipsec _updown</B>
+
+provides no help in controlling a modern firewall.
+<P>
+
+Including attributes of the keying channel
+(authentication methods,
+<B>ikelifetime</B>,
+
+etc.)
+as an attribute of a connection,
+rather than of a participant pair, is dubious and incurs limitations.
+<P>
+
+<I>Ipsec_manual</I>
+
+is not nearly as generous about the syntax of subnets,
+addresses, etc. as the usual FreeS/WAN user interfaces.
+Four-component dotted-decimal must be used for all addresses.
+It
+<I>is</I>
+
+smart enough to translate bit-count netmasks to dotted-decimal form.
+<P>
+
+It would be good to have a line-continuation syntax,
+especially for the very long lines involved in
+RSA signature keys.
+<P>
+
+The ability to specify different identities,
+<B>authby</B>,
+
+and public keys for different automatic-keyed connections
+between the same participants is misleading;
+this doesn't work dependably because the identity of the participants
+is not known early enough.
+This is especially awkward for the ``Road Warrior'' case,
+where the remote IP address is specified as
+<B>0.0.0.0</B>,
+
+and that is considered to be the ``participant'' for such connections.
+<P>
+
+In principle it might be necessary to control MTU on an
+interface-by-interface basis,
+rather than with the single global override that
+<B>overridemtu</B>
+
+provides.
+<P>
+
+A number of features which <I>could</I> be implemented in
+both manual and automatic keying
+actually are not yet implemented for manual keying.
+This is unlikely to be fixed any time soon.
+<P>
+
+If conns are to be added before DNS is available,
+<B>left=</B><I>FQDN</I>,
+<B>leftnextop=</B><I>FQDN</I>,
+and
+<B>leftrsasigkey=%dnsonload</B>
+
+will fail.
+<I><A HREF="ipsec_pluto.8.html">ipsec_pluto</A></I>(8)
+
+does not actually use the public key for our side of a conn but it
+isn't generally known at a add-time which side is ours (Road Warrior
+and Opportunistic conns are currently exceptions).
+<P>
+
+The <B>myid</B> option does not affect explicit <B> ipsec auto --add</B> or <B>ipsec auto --replace</B> commands for implicit conns.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAD">CONN SECTIONS</A><DD>
+<DL>
+<DT><A HREF="#lbAE">CONN PARAMETERS:  GENERAL</A><DD>
+<DT><A HREF="#lbAF">CONN PARAMETERS:  AUTOMATIC KEYING</A><DD>
+<DT><A HREF="#lbAG">CONN PARAMETERS:  MANUAL KEYING</A><DD>
+</DL>
+<DT><A HREF="#lbAH">CONFIG SECTIONS</A><DD>
+<DT><A HREF="#lbAI">IMPLICIT CONNS</A><DD>
+<DT><A HREF="#lbAJ">POLICY GROUP FILES</A><DD>
+<DT><A HREF="#lbAK">DEFAULT POLICY GROUPS</A><DD>
+<DT><A HREF="#lbAL">CHOOSING A CONNECTION</A><DD>
+<DT><A HREF="#lbAM">FILES</A><DD>
+<DT><A HREF="#lbAN">SEE ALSO</A><DD>
+<DT><A HREF="#lbAO">HISTORY</A><DD>
+<DT><A HREF="#lbAP">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec.secrets.5.html b/doc/manpage.d/ipsec.secrets.5.html
new file mode 100644
index 000000000..8abc1f492
--- /dev/null
+++ b/doc/manpage.d/ipsec.secrets.5.html
@@ -0,0 +1,227 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC.SECRETS</TITLE>
+</HEAD><BODY>
+<H1>IPSEC.SECRETS</H1>
+Section: File Formats (5)<BR>Updated: 28 March 1999<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec.secrets - secrets for IKE/IPsec authentication
+<A NAME="lbAC">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+The file <I>ipsec.secrets</I> holds a table of secrets.
+These secrets are used by <I><A HREF="ipsec_pluto.8.html">ipsec_pluto</A></I>(8), the FreeS/WAN Internet Key
+Exchange daemon, to authenticate other hosts.
+Currently there are two kinds of secrets: preshared secrets and
+
+RSA private keys.
+<P>
+
+It is vital that these secrets be protected.  The file should be owned
+by the super-user,
+and its permissions should be set to block all access by others.
+<P>
+
+The file is a sequence of entries and include directives.
+Here is an example.  Each entry or directive must start at the
+left margin, but if it continues beyond a single line, each continuation
+line must be indented.
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+# sample /etc/ipsec.secrets file for 10.1.0.1
+10.1.0.1 10.2.0.1: PSK &quot;secret shared by two hosts&quot;
+
+# an entry may be split across lines,
+# but indentation matters
+<A HREF="http://www.xs4all.nl">www.xs4all.nl</A> @<A HREF="http://www.kremvax.ru">www.kremvax.ru</A>
+&nbsp;&nbsp;&nbsp;&nbsp;10.6.0.1 10.7.0.1 1.8.0.1: PSK &quot;secret shared by 5&quot;
+
+# an RSA private key.
+# note that the lines are too wide for a
+# man page, so ... has been substituted for
+# the truncated part
+@my.com: rsa {
+&nbsp;&nbsp;&nbsp;&nbsp;Modulus:&nbsp;0syXpo/6waam+ZhSs8Lt6jnBzu3C4grtt...
+&nbsp;&nbsp;&nbsp;&nbsp;PublicExponent:&nbsp;0sAw==
+&nbsp;&nbsp;&nbsp;&nbsp;PrivateExponent:&nbsp;0shlGbVR1m8Z+7rhzSyenCaBN...
+&nbsp;&nbsp;&nbsp;&nbsp;Prime1:&nbsp;0s8njV7WTxzVzRz7AP+0OraDxmEAt1BL5l...
+&nbsp;&nbsp;&nbsp;&nbsp;Prime2:&nbsp;0s1LgR7/oUMo9BvfU8yRFNos1s211KX5K0...
+&nbsp;&nbsp;&nbsp;&nbsp;Exponent1:&nbsp;0soaXj85ihM5M2inVf/NfHmtLutVz4r...
+&nbsp;&nbsp;&nbsp;&nbsp;Exponent2:&nbsp;0sjdAL9VFizF+BKU4ohguJFzOd55OG6...
+&nbsp;&nbsp;&nbsp;&nbsp;Coefficient:&nbsp;0sK1LWwgnNrNFGZsS/2GuMBg9nYVZ...
+&nbsp;&nbsp;&nbsp;&nbsp;}
+
+include ipsec.*.secrets # get secrets from other files
+</PRE>
+
+</DL>
+
+<P>
+
+Each entry in the file is a list of indices, followed by a secret.
+The two parts are separated by a colon (<B>:</B>) that is
+followed by whitespace or a newline.  For compatability
+with the previous form of this file, if the key part is just a
+double-quoted string the colon may be left out.
+<P>
+
+An index is an IP address, or a Fully Qualified Domain Name, <A HREF="mailto:user@FQDN">user@FQDN</A>,
+<B>%any</B> or <B>%any6</B> (other kinds may come).  An IP address may be written
+in the familiar dotted quad form or as a domain name to be looked up
+when the file is loaded
+(or in any of the forms supported by the FreeS/WAN <I><A HREF="ipsec_ttoaddr.3.html">ipsec_ttoaddr</A></I>(3)
+routine).  In many cases it is a bad idea to use domain names because
+the name server may not be running or may be insecure.  To denote a
+Fully Qualified Domain Name (as opposed to an IP address denoted by
+its domain name), precede the name with an at sign (<B>@</B>).
+<P>
+
+Matching IDs with indices is fairly straightforward: they have to be
+equal.  In the case of a ``Road Warrior'' connection, if an equal
+match is not found for the Peer's ID, and it is in the form of an IP
+address, an index of <B>%any</B> will match the peer's IP address if IPV4
+and <B>%any6</B> will match a the peer's IP address if IPV6.
+Currently, the obsolete notation <B>0.0.0.0</B> may be used in place of
+<B>%any</B>.
+<P>
+
+An additional complexity
+arises in the case of authentication by preshared secret: the
+responder will need to look up the secret before the Peer's ID payload has
+been decoded, so the ID used will be the IP address.
+<P>
+
+To authenticate a connection between two hosts, the entry that most
+specifically matches the host and peer IDs is used.  An entry with no
+index will match any host and peer.  More specifically, an entry with one index will
+match a host and peer if the index matches the host's ID (the peer isn't
+considered).  Still more specifically, an entry with multiple indices will match a host and
+peer if the host ID and peer ID each match one of the indices.  If the key
+is for an asymmetric authentication technique (i.e. a public key
+system such as RSA), an entry with multiple indices will match a host
+and peer even if only the host ID matches an index (it is presumed that the
+multiple indices are all identities of the host).
+It is acceptable for two entries to be the best match as
+long as they agree about the secret or private key.
+<P>
+
+Authentication by preshared secret requires that both systems find the
+identical secret (the secret is not actually transmitted by the IKE
+protocol).  If both the host and peer appear in the index list, the
+same entry will be suitable for both systems so verbatim copying
+between systems can be used.  This naturally extends to larger groups
+sharing the same secret.  Thus multiple-index entries are best for PSK
+authentication.
+<P>
+
+Authentication by RSA Signatures requires that each host have its own private
+key.  A host could reasonably use a different private keys
+for different interfaces and for different peers.  But it would not
+be normal to share entries between systems.  Thus thus no-index and
+one-index forms of entry often make sense for RSA Signature authentication.
+<P>
+
+The key part of an entry may start with a token indicating the kind of
+key.  ``RSA'' signifies RSA private key and ``PSK'' signifies
+PreShared Key (case is ignored).  For compatability with previous
+forms of this file, PSK is the default.
+<P>
+
+A preshared secret is most conveniently represented as a sequence of
+characters, delimited by the double-quote
+character (<B>&quot;</B>).  The sequence cannot contain a newline or
+double-quote.  Strictly speaking, the secret is actually the sequence
+of bytes that is used in the file to represent the sequence of
+characters (excluding the delimiters).
+A preshared secret may also be represented, without quotes, in any form supported by
+<I><A HREF="ipsec_ttodata.3.html">ipsec_ttodata</A></I>(3).
+<P>
+
+An RSA private key is a composite of eight generally large numbers.  The notation
+used is a brace-enclosed list of field name and value pairs (see the example above).
+A suitable key, in a suitable format, may be generated by <I><A HREF="ipsec_rsasigkey.8.html">ipsec_rsasigkey</A></I>(8).
+The structure is very similar to that used by BIND 8.2.2 or later, but note that
+the numbers must have a ``0s'' prefix if they are in base 64.  The order of
+the fields is fixed.
+<P>
+
+The first token an entry must start in
+the first column of its line.  Subsequent tokens must be
+separated by whitespace,
+except for a colon token, which only needs to be followed by whitespace.
+A newline is taken as whitespace, but every
+line of an entry after the first must be indented.
+<P>
+
+Whitespace at the end of a line is ignored (except in the 0t
+notation for a key).  At the start of line or
+after whitespace, <B>#</B> and the following text up to the end of the
+line is treated as a comment.  Within entries, all lines must be
+indented (except for lines with no tokens).
+Outside entries, no line may be indented (this is to make sure that
+the file layout reflects its structure).
+<P>
+
+An include directive causes the contents of the named file to be processed
+before continuing with the current file.  The filename is subject to
+``globbing'' as in <I><A HREF="sh.1.html">sh</A></I>(1), so every file with a matching name
+is processed.  Includes may be nested to a modest
+depth (10, currently).  If the filename doesn't start with a <B>/</B>, the
+directory containing the current file is prepended to the name.  The
+include directive is a line that starts with the word <B>include</B>,
+followed by whitespace, followed by the filename (which must not contain
+whitespace).
+<A NAME="lbAD">&nbsp;</A>
+<H2>FILES</H2>
+
+/etc/ipsec.secrets
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+The rest of the FreeS/WAN distribution, in particular
+<I><A HREF="ipsec.conf.5.html">ipsec.conf</A></I>(5),
+<I><A HREF="ipsec.8.html">ipsec</A></I>(8),
+<I><A HREF="ipsec_newhostkey.8.html">ipsec_newhostkey</A></I>(8),
+<I><A HREF="ipsec_rsasigkey.8.html">ipsec_rsasigkey</A></I>(8),
+<I><A HREF="ipsec_showhostkey.8.html">ipsec_showhostkey</A></I>(8),
+<I><A HREF="ipsec_auto.8.html">ipsec_auto</A></I>(8) <B>--rereadsecrets</B>,
+and <I><A HREF="ipsec_pluto.8.html">ipsec_pluto</A></I>(8) <B>--listen</B>,.
+<BR>
+
+BIND 8.2.2 or later, <A HREF="ftp://ftp.isc.org/isc/bind/src/">ftp://ftp.isc.org/isc/bind/src/</A>
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Designed for the FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org">http://www.freeswan.org</A>&gt;
+by D. Hugh Redelmeier.
+<A NAME="lbAG">&nbsp;</A>
+<H2>BUGS</H2>
+
+If an ID is <B>0.0.0.0</B>, it will match <B>%any</B>;
+if it is <B>0::0</B>, it will match <B>%any6</B>.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAD">FILES</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+<DT><A HREF="#lbAG">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec__confread.8.html b/doc/manpage.d/ipsec__confread.8.html
new file mode 100644
index 000000000..ecc120c7e
--- /dev/null
+++ b/doc/manpage.d/ipsec__confread.8.html
@@ -0,0 +1,58 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of _CONFREAD</TITLE>
+</HEAD><BODY>
+<H1>_CONFREAD</H1>
+Section: Maintenance Commands (8)<BR>Updated: 25 Apr 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec _confread - internal routing to parse config file
+<A NAME="lbAC">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>_confread </I>
+
+is an internal script used for parsing /etc/ipsec.conf into a canonical format.
+<A NAME="lbAD">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_conf.8.html">ipsec_conf</A>(8)
+<A NAME="lbAE">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Man page written for the Linux FreeS/WAN project &lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Michael Richardson. Program written by Henry Spencer.
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAD">SEE ALSO</A><DD>
+<DT><A HREF="#lbAE">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec__copyright.8.html b/doc/manpage.d/ipsec__copyright.8.html
new file mode 100644
index 000000000..7f78b3feb
--- /dev/null
+++ b/doc/manpage.d/ipsec__copyright.8.html
@@ -0,0 +1,62 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of _COPYRIGHT</TITLE>
+</HEAD><BODY>
+<H1>_COPYRIGHT</H1>
+Section: Maintenance Commands (8)<BR>Updated: 25 Apr 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec _copyright - prints FreeSWAN copyright
+<A NAME="lbAC">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>_copyright</I>
+
+outputs the FreeSWAN copyright, and version numbers for &quot;ipsec --copyright&quot;
+<A NAME="lbAD">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8)
+<A NAME="lbAE">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Man page written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Michael Richardson. Program written by Henry Spencer.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAD">SEE ALSO</A><DD>
+<DT><A HREF="#lbAE">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec__include.8.html b/doc/manpage.d/ipsec__include.8.html
new file mode 100644
index 000000000..d85ee7852
--- /dev/null
+++ b/doc/manpage.d/ipsec__include.8.html
@@ -0,0 +1,67 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of _INCLUDE</TITLE>
+</HEAD><BODY>
+<H1>_INCLUDE</H1>
+Section: Maintenance Commands (8)<BR>Updated: 25 Apr 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec _include - internal script to process config files
+<A NAME="lbAC">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>_include</I>
+
+is used by 
+<I>_confread </I>
+
+to process 
+<B>include </B>
+
+directives in /etc/ipsec.conf.
+<A NAME="lbAD">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec__confread.8.html">ipsec__confread</A>(8)
+<A NAME="lbAE">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Man page written for the Linux FreeS/WAN project &lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Michael Richardson. Program written by Henry Spencer.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAD">SEE ALSO</A><DD>
+<DT><A HREF="#lbAE">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec__keycensor.8.html b/doc/manpage.d/ipsec__keycensor.8.html
new file mode 100644
index 000000000..22e574932
--- /dev/null
+++ b/doc/manpage.d/ipsec__keycensor.8.html
@@ -0,0 +1,64 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of _KEYCENSOR</TITLE>
+</HEAD><BODY>
+<H1>_KEYCENSOR</H1>
+Section: Maintenance Commands (8)<BR>Updated: 25 Apr 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec _keycensor - internal routine to remove sensitive information
+<A NAME="lbAC">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>_keycensor</I>
+
+is used by 
+<B>ipsec barf</B>
+
+to process the /etc/ipsec.secrets file, removing private key info.
+<A NAME="lbAD">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_barf.8.html">ipsec_barf</A>(8)
+<A NAME="lbAE">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Man page written for the Linux FreeS/WAN project &lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Michael Richardson. Original program by Henry Spencer.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAD">SEE ALSO</A><DD>
+<DT><A HREF="#lbAE">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec__plutoload.8.html b/doc/manpage.d/ipsec__plutoload.8.html
new file mode 100644
index 000000000..2c4968300
--- /dev/null
+++ b/doc/manpage.d/ipsec__plutoload.8.html
@@ -0,0 +1,64 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of _PLUTOLOAD</TITLE>
+</HEAD><BODY>
+<H1>_PLUTOLOAD</H1>
+Section: Maintenance Commands (8)<BR>Updated: 25 Apr 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec _plutoload - internal script to start pluto
+<A NAME="lbAC">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>_plutoload</I>
+
+is called by 
+<B>_plutorun</B>
+
+to actually start the pluto executable.
+<A NAME="lbAD">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_setup.8.html">ipsec_setup</A>(8), <A HREF="ipsec__realsetup.8.html">ipsec__realsetup</A>(8), <A HREF="ipsec__plutorun.8.html">ipsec__plutorun</A>(8)
+<A NAME="lbAE">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Man page written for the Linux FreeS/WAN project &lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Michael Richardson. Original program by Henry Spencer.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAD">SEE ALSO</A><DD>
+<DT><A HREF="#lbAE">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec__plutorun.8.html b/doc/manpage.d/ipsec__plutorun.8.html
new file mode 100644
index 000000000..1b5a1da11
--- /dev/null
+++ b/doc/manpage.d/ipsec__plutorun.8.html
@@ -0,0 +1,70 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of _PLUTORUN</TITLE>
+</HEAD><BODY>
+<H1>_PLUTORUN</H1>
+Section: Maintenance Commands (8)<BR>Updated: 25 Apr 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec _plutorun - internal script to start pluto
+<A NAME="lbAC">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>_plutorun</I>
+
+is called by
+<B>_realsetup</B>
+
+to configure and bring up 
+<B><A HREF="ipsec_pluto.8.html">ipsec_pluto</A>(8).</B>
+
+It calls 
+<B>_plutoload</B>
+
+to invoke pluto, and watches to makes sure that pluto is restarted if it fails.
+<A NAME="lbAD">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_setup.8.html">ipsec_setup</A>(8), <A HREF="ipsec__realsetup.8.html">ipsec__realsetup</A>(8), <A HREF="ipsec__plutoload.8.html">ipsec__plutoload</A>(8), <A HREF="ipsec_pluto.8.html">ipsec_pluto</A>(8).
+<A NAME="lbAE">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Man page written for the Linux FreeS/WAN project &lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Michael Richardson. Original program written by Henry Spencer.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAD">SEE ALSO</A><DD>
+<DT><A HREF="#lbAE">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec__realsetup.8.html b/doc/manpage.d/ipsec__realsetup.8.html
new file mode 100644
index 000000000..f45bec647
--- /dev/null
+++ b/doc/manpage.d/ipsec__realsetup.8.html
@@ -0,0 +1,68 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of _REALSETUP</TITLE>
+</HEAD><BODY>
+<H1>_REALSETUP</H1>
+Section: Maintenance Commands (8)<BR>Updated: 25 Apr 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec _realsetup - internal routine to start FreeS/WAN.
+<A NAME="lbAC">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>_realsetup</I>
+
+is called by the system init scripts to start the FreeS/WAN 
+system. It starts 
+<B>KLIPS </B>
+
+(the kernel component) and 
+<B>pluto </B>
+
+(the userspace keying component).
+<A NAME="lbAD">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec__klipsstart.8.html">ipsec__klipsstart</A>(8), <A HREF="ipsec__plutorun.8.html">ipsec__plutorun</A>(8).
+<A NAME="lbAE">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Man page written for the Linux FreeS/WAN project &lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Michael Richardson. Original program by Henry Spencer.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAD">SEE ALSO</A><DD>
+<DT><A HREF="#lbAE">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec__secretcensor.8.html b/doc/manpage.d/ipsec__secretcensor.8.html
new file mode 100644
index 000000000..6c6ea312d
--- /dev/null
+++ b/doc/manpage.d/ipsec__secretcensor.8.html
@@ -0,0 +1,65 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of _SECRETCENSOR</TITLE>
+</HEAD><BODY>
+<H1>_SECRETCENSOR</H1>
+Section: Maintenance Commands (8)<BR>Updated: 25 Apr 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec _secretcensor - internal routing to sanitize files
+<A NAME="lbAC">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>_secretcensor</I>
+
+is called by
+<B>ipsec barf</B>
+
+to process the /etc/ipsec.secrets file to remove the private key components
+from the file prior to revealing the contents.
+<A NAME="lbAD">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_barf.8.html">ipsec_barf</A>(8).
+<A NAME="lbAE">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Man page written for the Linux FreeS/WAN project &lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Michael Richardson. Original program by Henry Spencer.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAD">SEE ALSO</A><DD>
+<DT><A HREF="#lbAE">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec__startklips.8.html b/doc/manpage.d/ipsec__startklips.8.html
new file mode 100644
index 000000000..3ad565e57
--- /dev/null
+++ b/doc/manpage.d/ipsec__startklips.8.html
@@ -0,0 +1,63 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of _STARTKLIPS</TITLE>
+</HEAD><BODY>
+<H1>_STARTKLIPS</H1>
+Section: Maintenance Commands (8)<BR>Updated: 25 Apr 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec _startklips - internal script to bring up kernel components
+<A NAME="lbAC">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>_startklips</I>
+
+brings up the FreeS/WAN kernel component. This involves loading any
+required modules, attaching and configuring the ipsecX pseudo-devices and
+attaching the pseudo-devices to the physical devices.
+<A NAME="lbAD">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_tncfg.8.html">ipsec_tncfg</A>(8).
+<A NAME="lbAE">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Man page written for the Linux FreeS/WAN project &lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Michael Richardson. Original program by Henry Spencer.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAD">SEE ALSO</A><DD>
+<DT><A HREF="#lbAE">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec__updown.8.html b/doc/manpage.d/ipsec__updown.8.html
new file mode 100644
index 000000000..73bf8a343
--- /dev/null
+++ b/doc/manpage.d/ipsec__updown.8.html
@@ -0,0 +1,63 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of _UPDOWN</TITLE>
+</HEAD><BODY>
+<H1>_UPDOWN</H1>
+Section: Maintenance Commands (8)<BR>Updated: 25 Apr 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec _updown - klips manipulation script
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<I>_updown</I>
+
+is invoked by pluto when it has brought up a new connection. This script
+is used to insert the appropriate routing entries for IPsec operation.
+The interface to the script is documented in the pluto man page.
+<A NAME="lbAD">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_pluto.8.html">ipsec_pluto</A>(8).
+<A NAME="lbAE">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Man page written for the Linux FreeS/WAN project &lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Michael Richardson. Original program written by Henry Spencer.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">SEE ALSO</A><DD>
+<DT><A HREF="#lbAE">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_addrbytesof.3.html b/doc/manpage.d/ipsec_addrbytesof.3.html
new file mode 100644
index 000000000..ca1f857e7
--- /dev/null
+++ b/doc/manpage.d/ipsec_addrbytesof.3.html
@@ -0,0 +1,232 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_INITADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_INITADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 11 Sept 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec initaddr - initialize an ip_address
+<BR>
+
+ipsec addrtypeof - get address type of an ip_address
+<BR>
+
+ipsec addrlenof - get length of address within an ip_address
+<BR>
+
+ipsec addrbytesof - get copy of address within an ip_address
+<BR>
+
+ipsec addrbytesptr - get pointer to address within an ip_address
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *initaddr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int addrtypeof(const ip_address *src);</B>
+
+<BR>
+
+<B>size_t addrlenof(const ip_address *src);</B>
+
+<BR>
+
+<B>size_t addrbytesof(const ip_address *src,</B>
+
+<BR>
+&nbsp;
+<B>unsigned char *dst, size_t dstlen);</B>
+
+<BR>
+
+<B>size_t addrbytesptr(const ip_address *src,</B>
+
+<BR>
+&nbsp;
+<B>const unsigned char **dst);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+library uses an internal type
+<I>ip_address</I>
+
+to contain one of the (currently two) types of IP address.
+These functions provide basic tools for creating and examining this type.
+<P>
+
+<I>Initaddr</I>
+
+initializes a variable
+<I>*dst</I>
+
+of type
+<I>ip_address</I>
+
+from an address
+(in network byte order,
+indicated by a pointer
+<I>src</I>
+
+and a length
+<I>srclen</I>)
+
+and an address family
+<I>af</I>
+
+(typically
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>).
+
+The length must be consistent with the address family.
+<P>
+
+<I>Addrtypeof</I>
+
+returns the address type of an address,
+normally
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>.
+
+(The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file arranges to include the necessary headers for these
+names to be known.)
+<P>
+
+<I>Addrlenof</I>
+
+returns the size (in bytes) of the address within an
+<I>ip_address</I>,
+
+to permit storage allocation etc.
+<P>
+
+<I>Addrbytesof</I>
+
+copies the address within the
+<I>ip_address</I>
+
+<I>src</I>
+
+to the buffer indicated by the pointer
+<I>dst</I>
+
+and the length
+<I>dstlen</I>,
+
+and returns the address length (in bytes).
+If the address will not fit,
+as many bytes as will fit are copied;
+the returned length is still the full length.
+It is the caller's responsibility to check the
+returned value to ensure that there was enough room.
+<P>
+
+<I>Addrbytesptr</I>
+
+sets
+<I>*dst</I>
+
+to a pointer to the internal address within the
+<I>ip_address</I>,
+
+and returns the address length (in bytes).
+If
+<I>dst</I>
+
+is
+<B>NULL</B>,
+
+it just returns the address length.
+The pointer points to
+<B>const</B>
+
+to discourage misuse.
+<P>
+
+<I>Initaddr</I>
+
+returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<P>
+
+The functions which return
+<I>size_t</I>
+
+return
+<B>0</B>
+
+for a failure.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_ttoaddr.3.html">ipsec_ttoaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+An unknown address family is a fatal error for any of these functions
+except
+<I>addrtypeof</I>.
+
+An address-size mismatch is a fatal error for
+<I>initaddr</I>.
+
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+<I>Addrtypeof</I>
+
+should probably have been named
+<I>addrfamilyof</I>.
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_addrbytesptr.3.html b/doc/manpage.d/ipsec_addrbytesptr.3.html
new file mode 100644
index 000000000..ca1f857e7
--- /dev/null
+++ b/doc/manpage.d/ipsec_addrbytesptr.3.html
@@ -0,0 +1,232 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_INITADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_INITADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 11 Sept 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec initaddr - initialize an ip_address
+<BR>
+
+ipsec addrtypeof - get address type of an ip_address
+<BR>
+
+ipsec addrlenof - get length of address within an ip_address
+<BR>
+
+ipsec addrbytesof - get copy of address within an ip_address
+<BR>
+
+ipsec addrbytesptr - get pointer to address within an ip_address
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *initaddr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int addrtypeof(const ip_address *src);</B>
+
+<BR>
+
+<B>size_t addrlenof(const ip_address *src);</B>
+
+<BR>
+
+<B>size_t addrbytesof(const ip_address *src,</B>
+
+<BR>
+&nbsp;
+<B>unsigned char *dst, size_t dstlen);</B>
+
+<BR>
+
+<B>size_t addrbytesptr(const ip_address *src,</B>
+
+<BR>
+&nbsp;
+<B>const unsigned char **dst);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+library uses an internal type
+<I>ip_address</I>
+
+to contain one of the (currently two) types of IP address.
+These functions provide basic tools for creating and examining this type.
+<P>
+
+<I>Initaddr</I>
+
+initializes a variable
+<I>*dst</I>
+
+of type
+<I>ip_address</I>
+
+from an address
+(in network byte order,
+indicated by a pointer
+<I>src</I>
+
+and a length
+<I>srclen</I>)
+
+and an address family
+<I>af</I>
+
+(typically
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>).
+
+The length must be consistent with the address family.
+<P>
+
+<I>Addrtypeof</I>
+
+returns the address type of an address,
+normally
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>.
+
+(The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file arranges to include the necessary headers for these
+names to be known.)
+<P>
+
+<I>Addrlenof</I>
+
+returns the size (in bytes) of the address within an
+<I>ip_address</I>,
+
+to permit storage allocation etc.
+<P>
+
+<I>Addrbytesof</I>
+
+copies the address within the
+<I>ip_address</I>
+
+<I>src</I>
+
+to the buffer indicated by the pointer
+<I>dst</I>
+
+and the length
+<I>dstlen</I>,
+
+and returns the address length (in bytes).
+If the address will not fit,
+as many bytes as will fit are copied;
+the returned length is still the full length.
+It is the caller's responsibility to check the
+returned value to ensure that there was enough room.
+<P>
+
+<I>Addrbytesptr</I>
+
+sets
+<I>*dst</I>
+
+to a pointer to the internal address within the
+<I>ip_address</I>,
+
+and returns the address length (in bytes).
+If
+<I>dst</I>
+
+is
+<B>NULL</B>,
+
+it just returns the address length.
+The pointer points to
+<B>const</B>
+
+to discourage misuse.
+<P>
+
+<I>Initaddr</I>
+
+returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<P>
+
+The functions which return
+<I>size_t</I>
+
+return
+<B>0</B>
+
+for a failure.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_ttoaddr.3.html">ipsec_ttoaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+An unknown address family is a fatal error for any of these functions
+except
+<I>addrtypeof</I>.
+
+An address-size mismatch is a fatal error for
+<I>initaddr</I>.
+
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+<I>Addrtypeof</I>
+
+should probably have been named
+<I>addrfamilyof</I>.
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_addrcmp.3.html b/doc/manpage.d/ipsec_addrcmp.3.html
new file mode 100644
index 000000000..93ac522cd
--- /dev/null
+++ b/doc/manpage.d/ipsec_addrcmp.3.html
@@ -0,0 +1,274 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ANYADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ANYADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 28 Nov 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec sameaddr - are two addresses the same?
+<BR>
+
+ipsec addrcmp - ordered comparison of addresses
+<BR>
+
+ipsec samesubnet - are two subnets the same?
+<BR>
+
+ipsec addrinsubnet - is an address within a subnet?
+<BR>
+
+ipsec subnetinsubnet - is a subnet within another subnet?
+<BR>
+
+ipsec subnetishost - is a subnet a single host?
+<BR>
+
+ipsec samesaid - are two SA IDs the same?
+<BR>
+
+ipsec sameaddrtype - are two addresses of the same address family?
+<BR>
+
+ipsec samesubnettype - are two subnets of the same address family?
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>int sameaddr(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int addrcmp(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int samesubnet(const ip_subnet *a, const ip_subnet *b);</B>
+
+<BR>
+
+<B>int addrinsubnet(const ip_address *a, const ip_subnet *s);</B>
+
+<BR>
+
+<B>int subnetinsubnet(const ip_subnet *a, const ip_subnet *b);</B>
+
+<BR>
+
+<B>int subnetishost(const ip_subnet *s);</B>
+
+<BR>
+
+<B>int samesaid(const ip_said *a, const ip_said *b);</B>
+
+<BR>
+
+<B>int sameaddrtype(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int samesubnettype(const ip_subnet *a, const ip_subnet *b);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions do various comparisons and tests on the
+<I>ip_address</I>
+
+type and
+<I>ip_subnet</I>
+
+types.
+<P>
+
+<I>Sameaddr</I>
+
+returns
+non-zero
+if addresses
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+Addresses of different families are never identical.
+<P>
+
+<I>Addrcmp</I>
+
+returns
+<B>-1</B>,
+
+<B>0</B>,
+
+or
+<B>1</B>
+
+respectively
+if address
+<I>a</I>
+
+is less than, equal to, or greater than
+<I>b</I>.
+
+If they are not of the same address family,
+they are never equal;
+the ordering reported in this case is arbitrary
+(and probably not useful) but consistent.
+<P>
+
+<I>Samesubnet</I>
+
+returns
+non-zero
+if subnets
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+Subnets of different address families are never identical.
+<P>
+
+<I>Addrinsubnet</I>
+
+returns
+non-zero
+if address
+<I>a</I>
+
+is within subnet
+<I>s</I>
+
+and
+<B>0</B>
+
+otherwise.
+An address is never within a
+subnet of a different address family.
+<P>
+
+<I>Subnetinsubnet</I>
+
+returns
+non-zero
+if subnet
+<I>a</I>
+
+is a subset of subnet
+<I>b</I>
+
+and
+<B>0</B>
+
+otherwise.
+A subnet is deemed to be a subset of itself.
+A subnet is never a subset of another
+subnet if their address families differ.
+<P>
+
+<I>Subnetishost</I>
+
+returns
+non-zero
+if subnet
+<I>s</I>
+
+is in fact only a single host,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Samesaid</I>
+
+returns
+non-zero
+if SA IDs
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Sameaddrtype</I>
+
+returns
+non-zero
+if addresses
+<I>a</I>
+
+and
+<I>b</I>
+
+are of the same address family,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Samesubnettype</I>
+
+returns
+non-zero
+if subnets
+<I>a</I>
+
+and
+<I>b</I>
+
+are of the same address family,
+and
+<B>0</B>
+
+otherwise.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_initaddr.3.html">ipsec_initaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_addrinsubnet.3.html b/doc/manpage.d/ipsec_addrinsubnet.3.html
new file mode 100644
index 000000000..93ac522cd
--- /dev/null
+++ b/doc/manpage.d/ipsec_addrinsubnet.3.html
@@ -0,0 +1,274 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ANYADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ANYADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 28 Nov 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec sameaddr - are two addresses the same?
+<BR>
+
+ipsec addrcmp - ordered comparison of addresses
+<BR>
+
+ipsec samesubnet - are two subnets the same?
+<BR>
+
+ipsec addrinsubnet - is an address within a subnet?
+<BR>
+
+ipsec subnetinsubnet - is a subnet within another subnet?
+<BR>
+
+ipsec subnetishost - is a subnet a single host?
+<BR>
+
+ipsec samesaid - are two SA IDs the same?
+<BR>
+
+ipsec sameaddrtype - are two addresses of the same address family?
+<BR>
+
+ipsec samesubnettype - are two subnets of the same address family?
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>int sameaddr(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int addrcmp(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int samesubnet(const ip_subnet *a, const ip_subnet *b);</B>
+
+<BR>
+
+<B>int addrinsubnet(const ip_address *a, const ip_subnet *s);</B>
+
+<BR>
+
+<B>int subnetinsubnet(const ip_subnet *a, const ip_subnet *b);</B>
+
+<BR>
+
+<B>int subnetishost(const ip_subnet *s);</B>
+
+<BR>
+
+<B>int samesaid(const ip_said *a, const ip_said *b);</B>
+
+<BR>
+
+<B>int sameaddrtype(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int samesubnettype(const ip_subnet *a, const ip_subnet *b);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions do various comparisons and tests on the
+<I>ip_address</I>
+
+type and
+<I>ip_subnet</I>
+
+types.
+<P>
+
+<I>Sameaddr</I>
+
+returns
+non-zero
+if addresses
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+Addresses of different families are never identical.
+<P>
+
+<I>Addrcmp</I>
+
+returns
+<B>-1</B>,
+
+<B>0</B>,
+
+or
+<B>1</B>
+
+respectively
+if address
+<I>a</I>
+
+is less than, equal to, or greater than
+<I>b</I>.
+
+If they are not of the same address family,
+they are never equal;
+the ordering reported in this case is arbitrary
+(and probably not useful) but consistent.
+<P>
+
+<I>Samesubnet</I>
+
+returns
+non-zero
+if subnets
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+Subnets of different address families are never identical.
+<P>
+
+<I>Addrinsubnet</I>
+
+returns
+non-zero
+if address
+<I>a</I>
+
+is within subnet
+<I>s</I>
+
+and
+<B>0</B>
+
+otherwise.
+An address is never within a
+subnet of a different address family.
+<P>
+
+<I>Subnetinsubnet</I>
+
+returns
+non-zero
+if subnet
+<I>a</I>
+
+is a subset of subnet
+<I>b</I>
+
+and
+<B>0</B>
+
+otherwise.
+A subnet is deemed to be a subset of itself.
+A subnet is never a subset of another
+subnet if their address families differ.
+<P>
+
+<I>Subnetishost</I>
+
+returns
+non-zero
+if subnet
+<I>s</I>
+
+is in fact only a single host,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Samesaid</I>
+
+returns
+non-zero
+if SA IDs
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Sameaddrtype</I>
+
+returns
+non-zero
+if addresses
+<I>a</I>
+
+and
+<I>b</I>
+
+are of the same address family,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Samesubnettype</I>
+
+returns
+non-zero
+if subnets
+<I>a</I>
+
+and
+<I>b</I>
+
+are of the same address family,
+and
+<B>0</B>
+
+otherwise.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_initaddr.3.html">ipsec_initaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_addrlenof.3.html b/doc/manpage.d/ipsec_addrlenof.3.html
new file mode 100644
index 000000000..ca1f857e7
--- /dev/null
+++ b/doc/manpage.d/ipsec_addrlenof.3.html
@@ -0,0 +1,232 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_INITADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_INITADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 11 Sept 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec initaddr - initialize an ip_address
+<BR>
+
+ipsec addrtypeof - get address type of an ip_address
+<BR>
+
+ipsec addrlenof - get length of address within an ip_address
+<BR>
+
+ipsec addrbytesof - get copy of address within an ip_address
+<BR>
+
+ipsec addrbytesptr - get pointer to address within an ip_address
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *initaddr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int addrtypeof(const ip_address *src);</B>
+
+<BR>
+
+<B>size_t addrlenof(const ip_address *src);</B>
+
+<BR>
+
+<B>size_t addrbytesof(const ip_address *src,</B>
+
+<BR>
+&nbsp;
+<B>unsigned char *dst, size_t dstlen);</B>
+
+<BR>
+
+<B>size_t addrbytesptr(const ip_address *src,</B>
+
+<BR>
+&nbsp;
+<B>const unsigned char **dst);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+library uses an internal type
+<I>ip_address</I>
+
+to contain one of the (currently two) types of IP address.
+These functions provide basic tools for creating and examining this type.
+<P>
+
+<I>Initaddr</I>
+
+initializes a variable
+<I>*dst</I>
+
+of type
+<I>ip_address</I>
+
+from an address
+(in network byte order,
+indicated by a pointer
+<I>src</I>
+
+and a length
+<I>srclen</I>)
+
+and an address family
+<I>af</I>
+
+(typically
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>).
+
+The length must be consistent with the address family.
+<P>
+
+<I>Addrtypeof</I>
+
+returns the address type of an address,
+normally
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>.
+
+(The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file arranges to include the necessary headers for these
+names to be known.)
+<P>
+
+<I>Addrlenof</I>
+
+returns the size (in bytes) of the address within an
+<I>ip_address</I>,
+
+to permit storage allocation etc.
+<P>
+
+<I>Addrbytesof</I>
+
+copies the address within the
+<I>ip_address</I>
+
+<I>src</I>
+
+to the buffer indicated by the pointer
+<I>dst</I>
+
+and the length
+<I>dstlen</I>,
+
+and returns the address length (in bytes).
+If the address will not fit,
+as many bytes as will fit are copied;
+the returned length is still the full length.
+It is the caller's responsibility to check the
+returned value to ensure that there was enough room.
+<P>
+
+<I>Addrbytesptr</I>
+
+sets
+<I>*dst</I>
+
+to a pointer to the internal address within the
+<I>ip_address</I>,
+
+and returns the address length (in bytes).
+If
+<I>dst</I>
+
+is
+<B>NULL</B>,
+
+it just returns the address length.
+The pointer points to
+<B>const</B>
+
+to discourage misuse.
+<P>
+
+<I>Initaddr</I>
+
+returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<P>
+
+The functions which return
+<I>size_t</I>
+
+return
+<B>0</B>
+
+for a failure.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_ttoaddr.3.html">ipsec_ttoaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+An unknown address family is a fatal error for any of these functions
+except
+<I>addrtypeof</I>.
+
+An address-size mismatch is a fatal error for
+<I>initaddr</I>.
+
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+<I>Addrtypeof</I>
+
+should probably have been named
+<I>addrfamilyof</I>.
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_addrtoa.3.html b/doc/manpage.d/ipsec_addrtoa.3.html
new file mode 100644
index 000000000..8f0d765e5
--- /dev/null
+++ b/doc/manpage.d/ipsec_addrtoa.3.html
@@ -0,0 +1,448 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ATOADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ATOADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 11 June 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec atoaddr, addrtoa - convert Internet addresses to and from ASCII
+<BR>
+
+ipsec atosubnet, subnettoa - convert subnet/mask ASCII form to and from addresses
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *atoaddr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>struct in_addr *addr);</B>
+
+<BR>
+
+<B>size_t addrtoa(struct in_addr addr, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<P>
+<B>const char *atosubnet(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>struct in_addr *addr, struct in_addr *mask);</B>
+
+<BR>
+
+<B>size_t subnettoa(struct in_addr addr, struct in_addr mask,</B>
+
+<BR>
+&nbsp;
+<B>int format, char *dst, size_t dstlen);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions are obsolete; see
+<I><A HREF="ipsec_ttoaddr.3.html">ipsec_ttoaddr</A></I>(3)
+
+for their replacements.
+<P>
+
+<I>Atoaddr</I>
+
+converts an ASCII name or dotted-decimal address into a binary address
+(in network byte order).
+<I>Addrtoa</I>
+
+does the reverse conversion, back to an ASCII dotted-decimal address.
+<I>Atosubnet</I>
+
+and
+<I>subnettoa</I>
+
+do likewise for the ``address/mask'' ASCII form used to write a
+specification of a subnet.
+<P>
+
+An address is specified in ASCII as a
+dotted-decimal address (e.g.
+<B>1.2.3.4</B>),
+
+an eight-digit network-order hexadecimal number with the usual C prefix (e.g.
+<B>0x01020304</B>,
+
+which is synonymous with
+<B>1.2.3.4</B>),
+
+an eight-digit host-order hexadecimal number with a
+<B>0h</B>
+
+prefix (e.g.
+<B>0h01020304</B>,
+
+which is synonymous with
+<B>1.2.3.4</B>
+
+on a big-endian host and
+<B>4.3.2.1</B>
+
+on a little-endian host),
+a DNS name to be looked up via
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3),
+
+or an old-style network name to be looked up via
+<I><A HREF="getnetbyname.3.html">getnetbyname</A></I>(3).
+
+<P>
+
+A dotted-decimal address may be incomplete, in which case
+ASCII-to-binary conversion implicitly appends
+as many instances of
+<B>.0</B>
+
+as necessary to bring it up to four components.
+The components of a dotted-decimal address are always taken as
+decimal, and leading zeros are ignored.
+For example,
+<B>10</B>
+
+is synonymous with
+<B>10.0.0.0</B>,
+
+and
+<B>128.009.000.032</B>
+
+is synonymous with
+<B>128.9.0.32</B>
+
+(the latter example is verbatim from RFC 1166).
+The result of
+<I>addrtoa</I>
+
+is always complete and does not contain leading zeros.
+<P>
+
+The letters in
+a hexadecimal address may be uppercase or lowercase or any mixture thereof.
+Use of hexadecimal addresses is
+<B>strongly</B>
+
+<B>discouraged</B>;
+
+they are included only to save hassles when dealing with
+the handful of perverted programs which already print 
+network addresses in hexadecimal.
+<P>
+
+DNS names may be complete (optionally terminated with a ``.'')
+or incomplete, and are looked up as specified by local system configuration
+(see
+<I><A HREF="resolver.5.html">resolver</A></I>(5)).
+
+The
+<I>h_addr</I>
+
+value returned by
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3)
+
+is used,
+so with current DNS implementations,
+the result when the name corresponds to more than one address is
+difficult to predict.
+Name lookup resorts to
+<I><A HREF="getnetbyname.3.html">getnetbyname</A></I>(3)
+
+only if
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3)
+
+fails.
+<P>
+
+A subnet specification is of the form <I>network</I><B>/</B><I>mask</I>.
+The
+<I>network</I>
+
+and
+<I>mask</I>
+
+can be any form acceptable to
+<I>atoaddr</I>.
+
+In addition, the
+<I>mask</I>
+
+can be a decimal integer (leading zeros ignored) giving a bit count,
+in which case
+it stands for a mask with that number of high bits on and all others off
+(e.g.,
+<B>24</B>
+
+means
+<B>255.255.255.0</B>).
+
+In any case, the mask must be contiguous
+(a sequence of high bits on and all remaining low bits off).
+As a special case, the subnet specification
+<B>%default</B>
+
+is a synonym for
+<B>0.0.0.0/0</B>.
+
+<P>
+
+<I>Atosubnet</I>
+
+ANDs the mask with the address before returning,
+so that any non-network bits in the address are turned off
+(e.g.,
+<B>10.1.2.3/24</B>
+
+is synonymous with
+<B>10.1.2.0/24</B>).
+
+<I>Subnettoa</I>
+
+generates the decimal-integer-bit-count
+form of the mask,
+with no leading zeros,
+unless the mask is non-contiguous.
+<P>
+
+The
+<I>srclen</I>
+
+parameter of
+<I>atoaddr</I>
+
+and
+<I>atosubnet</I>
+
+specifies the length of the ASCII string pointed to by
+<I>src</I>;
+
+it is an error for there to be anything else
+(e.g., a terminating NUL) within that length.
+As a convenience for cases where an entire NUL-terminated string is
+to be converted,
+a
+<I>srclen</I>
+
+value of
+<B>0</B>
+
+is taken to mean
+<B>strlen(src)</B>.
+
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of
+<I>addrtoa</I>
+
+and
+<I>subnettoa</I>
+
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+The
+<I>freeswan.h</I>
+
+header file defines constants,
+<B>ADDRTOA_BUF</B>
+
+and
+<B>SUBNETTOA_BUF</B>,
+
+which are the sizes of buffers just large enough for worst-case results.
+<P>
+
+The
+<I>format</I>
+
+parameter of
+<I>addrtoa</I>
+
+and
+<I>subnettoa</I>
+
+specifies what format is to be used for the conversion.
+The value
+<B>0</B>
+
+(not the ASCII character
+<B>'0'</B>,
+
+but a zero value)
+specifies a reasonable default,
+and is in fact the only format currently available.
+This parameter is a hedge against future needs.
+<P>
+
+The ASCII-to-binary functions return NULL for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+The binary-to-ASCII functions return
+<B>0</B>
+
+for a failure, and otherwise
+always return the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL;
+it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>atoaddr</I>
+
+are:
+empty input;
+attempt to allocate temporary storage for a very long name failed;
+name lookup failed;
+syntax error in dotted-decimal form;
+dotted-decimal component too large to fit in 8 bits.
+<P>
+
+Fatal errors in
+<I>atosubnet</I>
+
+are:
+no
+<B>/</B>
+
+in
+<I>src</I>;
+
+<I>atoaddr</I>
+
+error in conversion of
+<I>network</I>
+
+or
+<I>mask</I>;
+
+bit-count mask too big;
+mask non-contiguous.
+<P>
+
+Fatal errors in
+<I>addrtoa</I>
+
+and
+<I>subnettoa</I>
+
+are:
+unknown format.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+The interpretation of incomplete dotted-decimal addresses
+(e.g.
+<B>10/24</B>
+
+means
+<B>10.0.0.0/24</B>)
+
+differs from that of some older conversion
+functions, e.g. those of
+<I><A HREF="inet.3.html">inet</A></I>(3).
+
+The behavior of the older functions has never been
+particularly consistent or particularly useful.
+<P>
+
+Ignoring leading zeros in dotted-decimal components and bit counts
+is arguably the most useful behavior in this application,
+but it might occasionally cause confusion with the historical use of leading 
+zeros to denote octal numbers.
+<P>
+
+It is barely possible that somebody, somewhere,
+might have a legitimate use for non-contiguous subnet masks.
+<P>
+
+<I><A HREF="Getnetbyname.3.html">Getnetbyname</A></I>(3)
+
+is a historical dreg.
+<P>
+
+The restriction of ASCII-to-binary error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The ASCII-to-binary error-reporting convention lends itself
+to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = atoaddr( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_addrtosubnet.3.html b/doc/manpage.d/ipsec_addrtosubnet.3.html
new file mode 100644
index 000000000..e442a9100
--- /dev/null
+++ b/doc/manpage.d/ipsec_addrtosubnet.3.html
@@ -0,0 +1,238 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_INITSUBNET</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_INITSUBNET</H1>
+Section: C Library Functions (3)<BR>Updated: 12 March 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec initsubnet - initialize an ip_subnet
+<BR>
+
+ipsec addrtosubnet - initialize a singleton ip_subnet
+<BR>
+
+ipsec subnettypeof - get address type of an ip_subnet
+<BR>
+
+ipsec masktocount - convert subnet mask to bit count
+<BR>
+
+ipsec networkof - get base address of an ip_subnet
+<BR>
+
+ipsec maskof - get subnet mask of an ip_subnet
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *initsubnet(const ip_address *addr,</B>
+
+<BR>
+&nbsp;
+<B>int maskbits, int clash, ip_subnet *dst);</B>
+
+<BR>
+
+<B>const char *addrtosubnet(const ip_address *addr,</B>
+
+<BR>
+&nbsp;
+<B>ip_subnet *dst);</B>
+
+<P>
+<B>int subnettypeof(const ip_subnet *src);</B>
+
+<BR>
+
+<B>int masktocount(const ip_address *src);</B>
+
+<BR>
+
+<B>void networkof(const ip_subnet *src, ip_address *dst);</B>
+
+<BR>
+
+<B>void maskof(const ip_subnet *src, ip_address *dst);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+library uses an internal type
+<I>ip_subnet</I>
+
+to contain a description of an IP subnet
+(base address plus mask).
+These functions provide basic tools for creating and examining this type.
+<P>
+
+<I>Initsubnet</I>
+
+initializes a variable
+<I>*dst</I>
+
+of type
+<I>ip_subnet</I>
+
+from a base address and
+a count of mask bits.
+The
+<I>clash</I>
+
+parameter specifies what to do if the base address includes
+<B>1</B>
+
+bits outside the prefix specified by the mask
+(that is, in the ``host number'' part of the address):
+<DL COMPACT><DT><DD>
+<DL COMPACT>
+<DT>'0'<DD>
+zero out host-number bits
+<DT>'x'<DD>
+non-zero host-number bits are an error
+</DL>
+</DL>
+
+<P>
+
+<I>Initsubnet</I>
+
+returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<P>
+
+<I>Addrtosubnet</I>
+
+initializes an
+<I>ip_subnet</I>
+
+variable
+<I>*dst</I>
+
+to a ``singleton subnet'' containing the single address
+<I>*addr</I>.
+
+It returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure.
+<P>
+
+<I>Subnettypeof</I>
+
+returns the address type of a subnet,
+normally
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>.
+
+(The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file arranges to include the necessary headers for these
+names to be known.)
+<P>
+
+<I>Masktocount</I>
+
+converts a subnet mask, expressed as an address, to a bit count
+suitable for use with
+<I>initsubnet</I>.
+
+It returns
+<B>-1</B>
+
+for error; see DIAGNOSTICS.
+<P>
+
+<I>Networkof</I>
+
+fills in
+<I>*dst</I>
+
+with the base address of subnet
+<I>src</I>.
+
+<P>
+
+<I>Maskof</I>
+
+fills in
+<I>*dst</I>
+
+with the subnet mask of subnet
+<I>src</I>,
+
+expressed as an address.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_ttosubnet.3.html">ipsec_ttosubnet</A>(3), <A HREF="ipsec_rangetosubnet.3.html">ipsec_rangetosubnet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>initsubnet</I>
+
+are:
+unknown address family;
+unknown
+<I>clash</I>
+
+value;
+impossible mask bit count;
+non-zero host-number bits and
+<I>clash</I>
+
+is
+<B>'x'</B>.
+
+Fatal errors in
+<I>addrtosubnet</I>
+
+are:
+unknown address family.
+Fatal errors in
+<I>masktocount</I>
+
+are:
+unknown address family;
+mask bits not contiguous.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_addrtot.3.html b/doc/manpage.d/ipsec_addrtot.3.html
new file mode 100644
index 000000000..eccb946e6
--- /dev/null
+++ b/doc/manpage.d/ipsec_addrtot.3.html
@@ -0,0 +1,569 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_TTOADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_TTOADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 28 Sept 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec ttoaddr, tnatoaddr, addrtot - convert Internet addresses to and from text
+<BR>
+
+ipsec ttosubnet, subnettot - convert subnet/mask text form to and from addresses
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *ttoaddr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int af, ip_address *addr);</B>
+
+<BR>
+
+<B>const char *tnatoaddr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int af, ip_address *addr);</B>
+
+<BR>
+
+<B>size_t addrtot(const ip_address *addr, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<P>
+<B>const char *ttosubnet(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int af, ip_subnet *dst);</B>
+
+<BR>
+
+<B>size_t subnettot(const ip_subnet *sub, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Ttoaddr</I>
+
+converts a text-string name or numeric address into a binary address
+(in network byte order).
+<I>Tnatoaddr</I>
+
+does the same conversion,
+but the only text forms it accepts are
+the ``official'' forms of
+numeric address (dotted-decimal for IPv4, colon-hex for IPv6).
+<I>Addrtot</I>
+
+does the reverse conversion, from binary address back to a text form.
+<I>Ttosubnet</I>
+
+and
+<I>subnettot</I>
+
+do likewise for the ``address/mask'' form used to write a
+specification of a subnet.
+<P>
+
+An IPv4 address is specified in text as a
+dotted-decimal address (e.g.
+<B>1.2.3.4</B>),
+
+an eight-digit network-order hexadecimal number with the usual C prefix (e.g.
+<B>0x01020304</B>,
+
+which is synonymous with
+<B>1.2.3.4</B>),
+
+an eight-digit host-order hexadecimal number with a
+<B>0h</B>
+
+prefix (e.g.
+<B>0h01020304</B>,
+
+which is synonymous with
+<B>1.2.3.4</B>
+
+on a big-endian host and
+<B>4.3.2.1</B>
+
+on a little-endian host),
+a DNS name to be looked up via
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3),
+
+or an old-style network name to be looked up via
+<I><A HREF="getnetbyname.3.html">getnetbyname</A></I>(3).
+
+<P>
+
+A dotted-decimal address may be incomplete, in which case
+text-to-binary conversion implicitly appends
+as many instances of
+<B>.0</B>
+
+as necessary to bring it up to four components.
+The components of a dotted-decimal address are always taken as
+decimal, and leading zeros are ignored.
+For example,
+<B>10</B>
+
+is synonymous with
+<B>10.0.0.0</B>,
+
+and
+<B>128.009.000.032</B>
+
+is synonymous with
+<B>128.9.0.32</B>
+
+(the latter example is verbatim from RFC 1166).
+The result of applying
+<I>addrtot</I>
+
+to an IPv4 address is always complete and does not contain leading zeros.
+<P>
+
+Use of hexadecimal addresses is
+<B>strongly</B>
+
+<B>discouraged</B>;
+
+they are included only to save hassles when dealing with
+the handful of perverted programs which already print 
+network addresses in hexadecimal.
+<P>
+
+An IPv6 address is specified in text with
+colon-hex notation (e.g.
+<B>0:56:78ab:22:33:44:55:66</B>),
+
+colon-hex with
+<B>::</B>
+
+abbreviating at most one subsequence of multiple zeros (e.g.
+<B>99:ab::54:068</B>,
+
+which is synonymous with
+<B>99:ab:0:0:0:0:54:68</B>),
+
+or a DNS name to be looked up via
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3).
+
+The result of applying
+<I>addrtot</I>
+
+to an IPv6 address will use
+<B>::</B>
+
+abbreviation if possible,
+and will not contain leading zeros.
+<P>
+
+The letters in hexadecimal
+may be uppercase or lowercase or any mixture thereof.
+<P>
+
+DNS names may be complete (optionally terminated with a ``.'')
+or incomplete, and are looked up as specified by local system configuration
+(see
+<I><A HREF="resolver.5.html">resolver</A></I>(5)).
+
+The
+<I>h_addr</I>
+
+value returned by
+<I><A HREF="gethostbyname2.3.html">gethostbyname2</A></I>(3)
+
+is used,
+so with current DNS implementations,
+the result when the name corresponds to more than one address is
+difficult to predict.
+IPv4 name lookup resorts to
+<I><A HREF="getnetbyname.3.html">getnetbyname</A></I>(3)
+
+only if
+<I><A HREF="gethostbyname2.3.html">gethostbyname2</A></I>(3)
+
+fails.
+<P>
+
+A subnet specification is of the form <I>network</I><B>/</B><I>mask</I>.
+The
+<I>network</I>
+
+and
+<I>mask</I>
+
+can be any form acceptable to
+<I>ttoaddr</I>.
+
+In addition, and preferably, the
+<I>mask</I>
+
+can be a decimal integer (leading zeros ignored) giving a bit count,
+in which case
+it stands for a mask with that number of high bits on and all others off
+(e.g.,
+<B>24</B>
+
+in IPv4 means
+<B>255.255.255.0</B>).
+
+In any case, the mask must be contiguous
+(a sequence of high bits on and all remaining low bits off).
+As a special case, the subnet specification
+<B>%default</B>
+
+is a synonym for
+<B>0.0.0.0/0</B>
+
+or
+<B>::/0</B>
+
+in IPv4 or IPv6 respectively.
+<P>
+
+<I>Ttosubnet</I>
+
+ANDs the mask with the address before returning,
+so that any non-network bits in the address are turned off
+(e.g.,
+<B>10.1.2.3/24</B>
+
+is synonymous with
+<B>10.1.2.0/24</B>).
+
+<I>Subnettot</I>
+
+always generates the decimal-integer-bit-count
+form of the mask,
+with no leading zeros.
+<P>
+
+The
+<I>srclen</I>
+
+parameter of
+<I>ttoaddr</I>
+
+and
+<I>ttosubnet</I>
+
+specifies the length of the text string pointed to by
+<I>src</I>;
+
+it is an error for there to be anything else
+(e.g., a terminating NUL) within that length.
+As a convenience for cases where an entire NUL-terminated string is
+to be converted,
+a
+<I>srclen</I>
+
+value of
+<B>0</B>
+
+is taken to mean
+<B>strlen(src)</B>.
+
+<P>
+
+The
+<I>af</I>
+
+parameter of
+<I>ttoaddr</I>
+
+and
+<I>ttosubnet</I>
+
+specifies the address family of interest.
+It should be either
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>.
+
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of
+<I>addrtot</I>
+
+and
+<I>subnettot</I>
+
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+The
+<I>freeswan.h</I>
+
+header file defines constants,
+<B>ADDRTOT_BUF</B>
+
+and
+<B>SUBNETTOT_BUF</B>,
+
+which are the sizes of buffers just large enough for worst-case results.
+<P>
+
+The
+<I>format</I>
+
+parameter of
+<I>addrtot</I>
+
+and
+<I>subnettot</I>
+
+specifies what format is to be used for the conversion.
+The value
+<B>0</B>
+
+(not the character
+<B>'0'</B>,
+
+but a zero value)
+specifies a reasonable default,
+and is in fact the only format currently available in
+<I>subnettot</I>.
+
+<I>Addrtot</I>
+
+also accepts format values
+<B>'r'</B>
+
+(signifying a text form suitable for DNS reverse lookups,
+e.g.
+<B>4.3.2.1.IN-ADDR.ARPA.</B>
+
+for IPv4 and
+RFC 2874 format for IPv6),
+and
+<B>'R'</B>
+
+(signifying an alternate reverse-lookup form,
+an error for IPv4 and RFC 1886 format for IPv6).
+Reverse-lookup names always end with a ``.''.
+<P>
+
+The text-to-binary functions return NULL for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+The binary-to-text functions return
+<B>0</B>
+
+for a failure, and otherwise
+always return the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL;
+it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>ttoaddr</I>
+
+are:
+empty input;
+unknown address family;
+attempt to allocate temporary storage for a very long name failed;
+name lookup failed;
+syntax error in dotted-decimal or colon-hex form;
+dotted-decimal or colon-hex component too large.
+<P>
+
+Fatal errors in
+<I>ttosubnet</I>
+
+are:
+no
+<B>/</B>
+
+in
+<I>src</I>;
+
+<I>ttoaddr</I>
+
+error in conversion of
+<I>network</I>
+
+or
+<I>mask</I>;
+
+bit-count mask too big;
+mask non-contiguous.
+<P>
+
+Fatal errors in
+<I>addrtot</I>
+
+and
+<I>subnettot</I>
+
+are:
+unknown format.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+The interpretation of incomplete dotted-decimal addresses
+(e.g.
+<B>10/24</B>
+
+means
+<B>10.0.0.0/24</B>)
+
+differs from that of some older conversion
+functions, e.g. those of
+<I><A HREF="inet.3.html">inet</A></I>(3).
+
+The behavior of the older functions has never been
+particularly consistent or particularly useful.
+<P>
+
+Ignoring leading zeros in dotted-decimal components and bit counts
+is arguably the most useful behavior in this application,
+but it might occasionally cause confusion with the historical use of leading 
+zeros to denote octal numbers.
+<P>
+
+<I>Ttoaddr</I>
+
+does not support the mixed colon-hex-dotted-decimal
+convention used to embed an IPv4 address in an IPv6 address.
+<P>
+
+<I>Addrtot</I>
+
+always uses the
+<B>::</B>
+
+abbreviation (which can appear only once in an address) for the
+<I>first</I>
+
+sequence of multiple zeros in an IPv6 address.
+One can construct addresses (unlikely ones) in which this is suboptimal.
+<P>
+
+<I>Addrtot</I>
+
+<B>'r'</B>
+
+conversion of an IPv6 address uses lowercase hexadecimal,
+not the uppercase used in RFC 2874's examples.
+It takes careful reading of RFCs 2874, 2673, and 2234 to realize
+that lowercase is technically legitimate here,
+and there may be software which botches this
+and hence would have trouble with lowercase hex.
+<P>
+
+Possibly
+<I>subnettot</I>
+
+ought to recognize the
+<B>%default</B>
+
+case and generate that string as its output.
+Currently it doesn't.
+<P>
+
+It is barely possible that somebody, somewhere,
+might have a legitimate use for non-contiguous subnet masks.
+<P>
+
+<I><A HREF="Getnetbyname.3.html">Getnetbyname</A></I>(3)
+
+is a historical dreg.
+<P>
+
+<I>Tnatoaddr</I>
+
+probably should enforce completeness of dotted-decimal addresses.
+<P>
+
+The restriction of text-to-binary error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The text-to-binary error-reporting convention lends itself
+to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = ttoaddr( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_addrtypeof.3.html b/doc/manpage.d/ipsec_addrtypeof.3.html
new file mode 100644
index 000000000..ca1f857e7
--- /dev/null
+++ b/doc/manpage.d/ipsec_addrtypeof.3.html
@@ -0,0 +1,232 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_INITADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_INITADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 11 Sept 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec initaddr - initialize an ip_address
+<BR>
+
+ipsec addrtypeof - get address type of an ip_address
+<BR>
+
+ipsec addrlenof - get length of address within an ip_address
+<BR>
+
+ipsec addrbytesof - get copy of address within an ip_address
+<BR>
+
+ipsec addrbytesptr - get pointer to address within an ip_address
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *initaddr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int addrtypeof(const ip_address *src);</B>
+
+<BR>
+
+<B>size_t addrlenof(const ip_address *src);</B>
+
+<BR>
+
+<B>size_t addrbytesof(const ip_address *src,</B>
+
+<BR>
+&nbsp;
+<B>unsigned char *dst, size_t dstlen);</B>
+
+<BR>
+
+<B>size_t addrbytesptr(const ip_address *src,</B>
+
+<BR>
+&nbsp;
+<B>const unsigned char **dst);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+library uses an internal type
+<I>ip_address</I>
+
+to contain one of the (currently two) types of IP address.
+These functions provide basic tools for creating and examining this type.
+<P>
+
+<I>Initaddr</I>
+
+initializes a variable
+<I>*dst</I>
+
+of type
+<I>ip_address</I>
+
+from an address
+(in network byte order,
+indicated by a pointer
+<I>src</I>
+
+and a length
+<I>srclen</I>)
+
+and an address family
+<I>af</I>
+
+(typically
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>).
+
+The length must be consistent with the address family.
+<P>
+
+<I>Addrtypeof</I>
+
+returns the address type of an address,
+normally
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>.
+
+(The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file arranges to include the necessary headers for these
+names to be known.)
+<P>
+
+<I>Addrlenof</I>
+
+returns the size (in bytes) of the address within an
+<I>ip_address</I>,
+
+to permit storage allocation etc.
+<P>
+
+<I>Addrbytesof</I>
+
+copies the address within the
+<I>ip_address</I>
+
+<I>src</I>
+
+to the buffer indicated by the pointer
+<I>dst</I>
+
+and the length
+<I>dstlen</I>,
+
+and returns the address length (in bytes).
+If the address will not fit,
+as many bytes as will fit are copied;
+the returned length is still the full length.
+It is the caller's responsibility to check the
+returned value to ensure that there was enough room.
+<P>
+
+<I>Addrbytesptr</I>
+
+sets
+<I>*dst</I>
+
+to a pointer to the internal address within the
+<I>ip_address</I>,
+
+and returns the address length (in bytes).
+If
+<I>dst</I>
+
+is
+<B>NULL</B>,
+
+it just returns the address length.
+The pointer points to
+<B>const</B>
+
+to discourage misuse.
+<P>
+
+<I>Initaddr</I>
+
+returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<P>
+
+The functions which return
+<I>size_t</I>
+
+return
+<B>0</B>
+
+for a failure.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_ttoaddr.3.html">ipsec_ttoaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+An unknown address family is a fatal error for any of these functions
+except
+<I>addrtypeof</I>.
+
+An address-size mismatch is a fatal error for
+<I>initaddr</I>.
+
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+<I>Addrtypeof</I>
+
+should probably have been named
+<I>addrfamilyof</I>.
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_anyaddr.3.html b/doc/manpage.d/ipsec_anyaddr.3.html
new file mode 100644
index 000000000..974236005
--- /dev/null
+++ b/doc/manpage.d/ipsec_anyaddr.3.html
@@ -0,0 +1,166 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ANYADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ANYADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 8 Sept 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec anyaddr - get &quot;any&quot; address
+<BR>
+
+ipsec isanyaddr - test address for equality to &quot;any&quot; address
+<BR>
+
+ipsec unspecaddr - get &quot;unspecified&quot; address
+<BR>
+
+ipsec isunspecaddr - test address for equality to &quot;unspecified&quot; address
+<BR>
+
+ipsec loopbackaddr - get loopback address
+<BR>
+
+ipsec isloopbackaddr - test address for equality to loopback address
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *anyaddr(int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int isanyaddr(const ip_address *src);</B>
+
+<BR>
+
+<B>const char *unspecaddr(int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int isunspecaddr(const ip_address *src);</B>
+
+<BR>
+
+<B>const char *loopbackaddr(int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int isloopbackaddr(const ip_address *src);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions fill in, and test for, special values of the
+<I>ip_address</I>
+
+type.
+<P>
+
+<I>Anyaddr</I>
+
+fills in the destination
+<I>*dst</I>
+
+with the ``any'' address of address family
+<I>af</I>
+
+(normally
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>).
+
+The IPv4 ``any'' address is the one embodied in the old
+<B>INADDR_ANY</B>
+
+macro.
+<P>
+
+<I>Isanyaddr</I>
+
+returns
+<B>1</B>
+
+if the
+<I>src</I>
+
+address equals the ``any'' address,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+Similarly,
+<I>unspecaddr</I>
+
+supplies, and
+<I>isunspecaddr</I>
+
+tests for,
+the ``unspecified'' address,
+which may be the same as the ``any'' address.
+<P>
+
+Similarly,
+<I>loopbackaddr</I>
+
+supplies, and
+<I>islookbackaddr</I>
+
+tests for,
+the loopback address.
+<P>
+
+<I>Anyaddr</I>,
+
+<I>unspecaddr</I>,
+
+and
+<I>loopbackaddr</I>
+
+return
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_addrtot.3.html">ipsec_addrtot</A>(3), <A HREF="ipsec_sameaddr.3.html">ipsec_sameaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in the address-supplying functions are:
+unknown address family.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_atoaddr.3.html b/doc/manpage.d/ipsec_atoaddr.3.html
new file mode 100644
index 000000000..8f0d765e5
--- /dev/null
+++ b/doc/manpage.d/ipsec_atoaddr.3.html
@@ -0,0 +1,448 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ATOADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ATOADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 11 June 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec atoaddr, addrtoa - convert Internet addresses to and from ASCII
+<BR>
+
+ipsec atosubnet, subnettoa - convert subnet/mask ASCII form to and from addresses
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *atoaddr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>struct in_addr *addr);</B>
+
+<BR>
+
+<B>size_t addrtoa(struct in_addr addr, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<P>
+<B>const char *atosubnet(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>struct in_addr *addr, struct in_addr *mask);</B>
+
+<BR>
+
+<B>size_t subnettoa(struct in_addr addr, struct in_addr mask,</B>
+
+<BR>
+&nbsp;
+<B>int format, char *dst, size_t dstlen);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions are obsolete; see
+<I><A HREF="ipsec_ttoaddr.3.html">ipsec_ttoaddr</A></I>(3)
+
+for their replacements.
+<P>
+
+<I>Atoaddr</I>
+
+converts an ASCII name or dotted-decimal address into a binary address
+(in network byte order).
+<I>Addrtoa</I>
+
+does the reverse conversion, back to an ASCII dotted-decimal address.
+<I>Atosubnet</I>
+
+and
+<I>subnettoa</I>
+
+do likewise for the ``address/mask'' ASCII form used to write a
+specification of a subnet.
+<P>
+
+An address is specified in ASCII as a
+dotted-decimal address (e.g.
+<B>1.2.3.4</B>),
+
+an eight-digit network-order hexadecimal number with the usual C prefix (e.g.
+<B>0x01020304</B>,
+
+which is synonymous with
+<B>1.2.3.4</B>),
+
+an eight-digit host-order hexadecimal number with a
+<B>0h</B>
+
+prefix (e.g.
+<B>0h01020304</B>,
+
+which is synonymous with
+<B>1.2.3.4</B>
+
+on a big-endian host and
+<B>4.3.2.1</B>
+
+on a little-endian host),
+a DNS name to be looked up via
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3),
+
+or an old-style network name to be looked up via
+<I><A HREF="getnetbyname.3.html">getnetbyname</A></I>(3).
+
+<P>
+
+A dotted-decimal address may be incomplete, in which case
+ASCII-to-binary conversion implicitly appends
+as many instances of
+<B>.0</B>
+
+as necessary to bring it up to four components.
+The components of a dotted-decimal address are always taken as
+decimal, and leading zeros are ignored.
+For example,
+<B>10</B>
+
+is synonymous with
+<B>10.0.0.0</B>,
+
+and
+<B>128.009.000.032</B>
+
+is synonymous with
+<B>128.9.0.32</B>
+
+(the latter example is verbatim from RFC 1166).
+The result of
+<I>addrtoa</I>
+
+is always complete and does not contain leading zeros.
+<P>
+
+The letters in
+a hexadecimal address may be uppercase or lowercase or any mixture thereof.
+Use of hexadecimal addresses is
+<B>strongly</B>
+
+<B>discouraged</B>;
+
+they are included only to save hassles when dealing with
+the handful of perverted programs which already print 
+network addresses in hexadecimal.
+<P>
+
+DNS names may be complete (optionally terminated with a ``.'')
+or incomplete, and are looked up as specified by local system configuration
+(see
+<I><A HREF="resolver.5.html">resolver</A></I>(5)).
+
+The
+<I>h_addr</I>
+
+value returned by
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3)
+
+is used,
+so with current DNS implementations,
+the result when the name corresponds to more than one address is
+difficult to predict.
+Name lookup resorts to
+<I><A HREF="getnetbyname.3.html">getnetbyname</A></I>(3)
+
+only if
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3)
+
+fails.
+<P>
+
+A subnet specification is of the form <I>network</I><B>/</B><I>mask</I>.
+The
+<I>network</I>
+
+and
+<I>mask</I>
+
+can be any form acceptable to
+<I>atoaddr</I>.
+
+In addition, the
+<I>mask</I>
+
+can be a decimal integer (leading zeros ignored) giving a bit count,
+in which case
+it stands for a mask with that number of high bits on and all others off
+(e.g.,
+<B>24</B>
+
+means
+<B>255.255.255.0</B>).
+
+In any case, the mask must be contiguous
+(a sequence of high bits on and all remaining low bits off).
+As a special case, the subnet specification
+<B>%default</B>
+
+is a synonym for
+<B>0.0.0.0/0</B>.
+
+<P>
+
+<I>Atosubnet</I>
+
+ANDs the mask with the address before returning,
+so that any non-network bits in the address are turned off
+(e.g.,
+<B>10.1.2.3/24</B>
+
+is synonymous with
+<B>10.1.2.0/24</B>).
+
+<I>Subnettoa</I>
+
+generates the decimal-integer-bit-count
+form of the mask,
+with no leading zeros,
+unless the mask is non-contiguous.
+<P>
+
+The
+<I>srclen</I>
+
+parameter of
+<I>atoaddr</I>
+
+and
+<I>atosubnet</I>
+
+specifies the length of the ASCII string pointed to by
+<I>src</I>;
+
+it is an error for there to be anything else
+(e.g., a terminating NUL) within that length.
+As a convenience for cases where an entire NUL-terminated string is
+to be converted,
+a
+<I>srclen</I>
+
+value of
+<B>0</B>
+
+is taken to mean
+<B>strlen(src)</B>.
+
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of
+<I>addrtoa</I>
+
+and
+<I>subnettoa</I>
+
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+The
+<I>freeswan.h</I>
+
+header file defines constants,
+<B>ADDRTOA_BUF</B>
+
+and
+<B>SUBNETTOA_BUF</B>,
+
+which are the sizes of buffers just large enough for worst-case results.
+<P>
+
+The
+<I>format</I>
+
+parameter of
+<I>addrtoa</I>
+
+and
+<I>subnettoa</I>
+
+specifies what format is to be used for the conversion.
+The value
+<B>0</B>
+
+(not the ASCII character
+<B>'0'</B>,
+
+but a zero value)
+specifies a reasonable default,
+and is in fact the only format currently available.
+This parameter is a hedge against future needs.
+<P>
+
+The ASCII-to-binary functions return NULL for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+The binary-to-ASCII functions return
+<B>0</B>
+
+for a failure, and otherwise
+always return the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL;
+it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>atoaddr</I>
+
+are:
+empty input;
+attempt to allocate temporary storage for a very long name failed;
+name lookup failed;
+syntax error in dotted-decimal form;
+dotted-decimal component too large to fit in 8 bits.
+<P>
+
+Fatal errors in
+<I>atosubnet</I>
+
+are:
+no
+<B>/</B>
+
+in
+<I>src</I>;
+
+<I>atoaddr</I>
+
+error in conversion of
+<I>network</I>
+
+or
+<I>mask</I>;
+
+bit-count mask too big;
+mask non-contiguous.
+<P>
+
+Fatal errors in
+<I>addrtoa</I>
+
+and
+<I>subnettoa</I>
+
+are:
+unknown format.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+The interpretation of incomplete dotted-decimal addresses
+(e.g.
+<B>10/24</B>
+
+means
+<B>10.0.0.0/24</B>)
+
+differs from that of some older conversion
+functions, e.g. those of
+<I><A HREF="inet.3.html">inet</A></I>(3).
+
+The behavior of the older functions has never been
+particularly consistent or particularly useful.
+<P>
+
+Ignoring leading zeros in dotted-decimal components and bit counts
+is arguably the most useful behavior in this application,
+but it might occasionally cause confusion with the historical use of leading 
+zeros to denote octal numbers.
+<P>
+
+It is barely possible that somebody, somewhere,
+might have a legitimate use for non-contiguous subnet masks.
+<P>
+
+<I><A HREF="Getnetbyname.3.html">Getnetbyname</A></I>(3)
+
+is a historical dreg.
+<P>
+
+The restriction of ASCII-to-binary error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The ASCII-to-binary error-reporting convention lends itself
+to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = atoaddr( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_atoasr.3.html b/doc/manpage.d/ipsec_atoasr.3.html
new file mode 100644
index 000000000..7c9e2c4aa
--- /dev/null
+++ b/doc/manpage.d/ipsec_atoasr.3.html
@@ -0,0 +1,294 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ATOASR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ATOASR</H1>
+Section: C Library Functions (3)<BR>Updated: 11 June 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec atoasr - convert ASCII to Internet address, subnet, or range
+<BR>
+
+ipsec rangetoa - convert Internet address range to ASCII
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *atoasr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>char *type, struct in_addr *addrs);</B>
+
+<BR>
+
+<B>size_t rangetoa(struct in_addr *addrs, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions are obsolete;
+there is no current equivalent,
+because so far they have not proved useful.
+<P>
+
+<I>Atoasr</I>
+
+converts an ASCII address, subnet, or address range
+into a suitable combination of binary addresses
+(in network byte order).
+<I>Rangetoa</I>
+
+converts an address range back into ASCII,
+using dotted-decimal form for the addresses
+(the other reverse conversions are handled by
+<I><A HREF="ipsec_addrtoa.3.html">ipsec_addrtoa</A></I>(3)
+
+and
+<I><A HREF="ipsec_subnettoa.3.html">ipsec_subnettoa</A></I>(3)).
+
+<P>
+
+A single address can be any form acceptable to
+<I><A HREF="ipsec_atoaddr.3.html">ipsec_atoaddr</A></I>(3):
+
+dotted decimal, DNS name, or hexadecimal number.
+A subnet
+specification uses the form <I>network</I><B>/</B><I>mask</I>
+interpreted by
+<I><A HREF="ipsec_atosubnet.3.html">ipsec_atosubnet</A></I>(3).
+
+<P>
+
+An address range is two
+<I><A HREF="ipsec_atoaddr.3.html">ipsec_atoaddr</A></I>(3)
+
+addresses separated by a
+<B>...</B>
+
+delimiter.
+If there are four dots rather than three, the first is taken as
+part of the begin address,
+e.g. for a complete DNS name which ends with
+<B>.</B>
+
+to suppress completion attempts.
+The begin address of a range must be
+less than or equal to the end address.
+<P>
+
+The
+<I>srclen</I>
+
+parameter of
+<I>atoasr</I>
+
+specifies the length of the ASCII string pointed to by
+<I>src</I>;
+
+it is an error for there to be anything else
+(e.g., a terminating NUL) within that length.
+As a convenience for cases where an entire NUL-terminated string is
+to be converted,
+a
+<I>srclen</I>
+
+value of
+<B>0</B>
+
+is taken to mean
+<B>strlen(src)</B>.
+
+<P>
+
+The
+<I>type</I>
+
+parameter of
+<I>atoasr</I>
+
+must point to a
+<B>char</B>
+
+variable used to record which form was found.
+The
+<I>addrs</I>
+
+parameter must point to a two-element array of
+<B>struct in_addr</B>
+
+which receives the results.
+The values stored into
+<B>*type</B>,
+
+and the corresponding values in the array, are:
+<P>
+
+
+
+<TT>&nbsp;&nbsp;&nbsp;</TT>*typeaddrs[0]addrs[1]<BR>
+<P>
+address<B>'a'</B>address-<BR>
+<BR>
+
+subnet<TT>&nbsp;</TT><B>'s'</B>networkmask<BR>
+<BR>
+
+range<TT>&nbsp;&nbsp;</TT><B>'r'</B>beginend<BR>
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of
+<I>rangetoa</I>
+
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+The
+<I>freeswan.h</I>
+
+header file defines a constant,
+<B>RANGETOA_BUF</B>,
+
+which is the size of a buffer just large enough for worst-case results.
+<P>
+
+The
+<I>format</I>
+
+parameter of
+<I>rangetoa</I>
+
+specifies what format is to be used for the conversion.
+The value
+<B>0</B>
+
+(not the ASCII character
+<B>'0'</B>,
+
+but a zero value)
+specifies a reasonable default,
+and is in fact the only format currently available.
+This parameter is a hedge against future needs.
+<P>
+
+<I>Atoasr</I>
+
+returns NULL for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<I>Rangetoa</I>
+
+returns
+<B>0</B>
+
+for a failure, and otherwise
+always returns the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL;
+it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec_atoaddr.3.html">ipsec_atoaddr</A>(3), <A HREF="ipsec_atosubnet.3.html">ipsec_atosubnet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>atoasr</I>
+
+are:
+empty input;
+error in
+<I><A HREF="ipsec_atoaddr.3.html">ipsec_atoaddr</A></I>(3)
+
+or
+<I><A HREF="ipsec_atosubnet.3.html">ipsec_atosubnet</A></I>(3)
+
+during conversion;
+begin address of range exceeds end address.
+<P>
+
+Fatal errors in
+<I>rangetoa</I>
+
+are:
+unknown format.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+The restriction of error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The error-reporting convention lends itself
+to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = atoasr( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_atosa.3.html b/doc/manpage.d/ipsec_atosa.3.html
new file mode 100644
index 000000000..9e2dc2f61
--- /dev/null
+++ b/doc/manpage.d/ipsec_atosa.3.html
@@ -0,0 +1,347 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ATOSA</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ATOSA</H1>
+Section: C Library Functions (3)<BR>Updated: 11 June 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec atosa, satoa - convert IPsec Security Association IDs to and from ASCII
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *atosa(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>struct sa_id *sa);</B>
+
+<BR>
+
+<B>size_t satoa(struct sa_id sa, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<P>
+<B>struct sa_id {</B>
+
+<BR>
+&nbsp;
+<B>struct in_addr dst;</B>
+
+<BR>
+&nbsp;
+<B>ipsec_spi_t spi;</B>
+
+<BR>
+&nbsp;
+<B>int proto;</B>
+
+<BR>
+
+<B>};</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions are obsolete; see
+<I><A HREF="ipsec_ttosa.3.html">ipsec_ttosa</A></I>(3)
+
+for their replacements.
+<P>
+
+<I>Atosa</I>
+
+converts an ASCII Security Association (SA) specifier into an
+<B>sa_id</B>
+
+structure (containing
+a destination-host address
+in network byte order,
+an SPI number in network byte order, and
+a protocol code).
+<I>Satoa</I>
+
+does the reverse conversion, back to an ASCII SA specifier.
+<P>
+
+An SA is specified in ASCII with a mail-like syntax, e.g.
+<B><A HREF="mailto:esp507@1.2.3.4">esp507@1.2.3.4</A></B>.
+
+An SA specifier contains
+a protocol prefix (currently
+<B>ah</B>,
+
+<B>esp</B>,
+
+or
+<B>tun</B>),
+
+an unsigned integer SPI number,
+and an IP address.
+The SPI number can be decimal or hexadecimal
+(with
+<B>0x</B>
+
+prefix), as accepted by
+<I><A HREF="ipsec_atoul.3.html">ipsec_atoul</A></I>(3).
+
+The IP address can be any form accepted by
+<I><A HREF="ipsec_atoaddr.3.html">ipsec_atoaddr</A></I>(3),
+
+e.g. dotted-decimal address or DNS name.
+<P>
+
+As a special case, the SA specifier
+<B>%passthrough</B>
+
+signifies the special SA used to indicate that packets should be
+passed through unaltered.
+(At present, this is a synonym for
+<B><A HREF="mailto:tun0x0@0.0.0.0">tun0x0@0.0.0.0</A></B>,
+
+but that is subject to change without notice.)
+This form is known to both
+<I>atosa</I>
+
+and
+<I>satoa</I>,
+
+so the internal form of
+<B>%passthrough</B>
+
+is never visible.
+<P>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file supplies the
+<B>sa_id</B>
+
+structure, as well as a data type
+<B>ipsec_spi_t</B>
+
+which is an unsigned 32-bit integer.
+(There is no consistency between kernel and user on what such a type
+is called, hence the header hides the differences.)
+<P>
+
+The protocol code uses the same numbers that IP does.
+For user convenience, given the difficulty in acquiring the exact set of
+protocol names used by the kernel,
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+defines the names
+<B>SA_ESP</B>,
+
+<B>SA_AH</B>,
+
+and
+<B>SA_IPIP</B>
+
+to have the same values as the kernel names
+<B>IPPROTO_ESP</B>,
+
+<B>IPPROTO_AH</B>,
+
+and
+<B>IPPROTO_IPIP</B>.
+
+<P>
+
+The
+<I>srclen</I>
+
+parameter of
+<I>atosa</I>
+
+specifies the length of the ASCII string pointed to by
+<I>src</I>;
+
+it is an error for there to be anything else
+(e.g., a terminating NUL) within that length.
+As a convenience for cases where an entire NUL-terminated string is
+to be converted,
+a
+<I>srclen</I>
+
+value of
+<B>0</B>
+
+is taken to mean
+<B>strlen(src)</B>.
+
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of
+<I>satoa</I>
+
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+The
+<I>freeswan.h</I>
+
+header file defines a constant,
+<B>SATOA_BUF</B>,
+
+which is the size of a buffer just large enough for worst-case results.
+<P>
+
+The
+<I>format</I>
+
+parameter of
+<I>satoa</I>
+
+specifies what format is to be used for the conversion.
+The value
+<B>0</B>
+
+(not the ASCII character
+<B>'0'</B>,
+
+but a zero value)
+specifies a reasonable default
+(currently
+lowercase protocol prefix, lowercase hexadecimal SPI, dotted-decimal address).
+The value
+<B>d</B>
+
+causes the SPI to be generated in decimal instead.
+<P>
+
+<I>Atosa</I>
+
+returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<I>Satoa</I>
+
+returns
+<B>0</B>
+
+for a failure, and otherwise
+always returns the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL;
+it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec_atoul.3.html">ipsec_atoul</A>(3), <A HREF="ipsec_atoaddr.3.html">ipsec_atoaddr</A>(3), <A HREF="inet.3.html">inet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>atosa</I>
+
+are:
+empty input;
+input too small to be a legal SA specifier;
+no
+<B>@</B>
+
+in input;
+unknown protocol prefix;
+conversion error in
+<I>atoul</I>
+
+or
+<I>atoaddr</I>.
+
+<P>
+
+Fatal errors in
+<I>satoa</I>
+
+are:
+unknown format; unknown protocol code.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+The
+<B>tun</B>
+
+protocol code is a FreeS/WANism which may eventually disappear.
+<P>
+
+The restriction of ASCII-to-binary error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The ASCII-to-binary error-reporting convention lends itself
+to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = atoaddr( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_atosubnet.3.html b/doc/manpage.d/ipsec_atosubnet.3.html
new file mode 100644
index 000000000..8f0d765e5
--- /dev/null
+++ b/doc/manpage.d/ipsec_atosubnet.3.html
@@ -0,0 +1,448 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ATOADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ATOADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 11 June 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec atoaddr, addrtoa - convert Internet addresses to and from ASCII
+<BR>
+
+ipsec atosubnet, subnettoa - convert subnet/mask ASCII form to and from addresses
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *atoaddr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>struct in_addr *addr);</B>
+
+<BR>
+
+<B>size_t addrtoa(struct in_addr addr, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<P>
+<B>const char *atosubnet(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>struct in_addr *addr, struct in_addr *mask);</B>
+
+<BR>
+
+<B>size_t subnettoa(struct in_addr addr, struct in_addr mask,</B>
+
+<BR>
+&nbsp;
+<B>int format, char *dst, size_t dstlen);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions are obsolete; see
+<I><A HREF="ipsec_ttoaddr.3.html">ipsec_ttoaddr</A></I>(3)
+
+for their replacements.
+<P>
+
+<I>Atoaddr</I>
+
+converts an ASCII name or dotted-decimal address into a binary address
+(in network byte order).
+<I>Addrtoa</I>
+
+does the reverse conversion, back to an ASCII dotted-decimal address.
+<I>Atosubnet</I>
+
+and
+<I>subnettoa</I>
+
+do likewise for the ``address/mask'' ASCII form used to write a
+specification of a subnet.
+<P>
+
+An address is specified in ASCII as a
+dotted-decimal address (e.g.
+<B>1.2.3.4</B>),
+
+an eight-digit network-order hexadecimal number with the usual C prefix (e.g.
+<B>0x01020304</B>,
+
+which is synonymous with
+<B>1.2.3.4</B>),
+
+an eight-digit host-order hexadecimal number with a
+<B>0h</B>
+
+prefix (e.g.
+<B>0h01020304</B>,
+
+which is synonymous with
+<B>1.2.3.4</B>
+
+on a big-endian host and
+<B>4.3.2.1</B>
+
+on a little-endian host),
+a DNS name to be looked up via
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3),
+
+or an old-style network name to be looked up via
+<I><A HREF="getnetbyname.3.html">getnetbyname</A></I>(3).
+
+<P>
+
+A dotted-decimal address may be incomplete, in which case
+ASCII-to-binary conversion implicitly appends
+as many instances of
+<B>.0</B>
+
+as necessary to bring it up to four components.
+The components of a dotted-decimal address are always taken as
+decimal, and leading zeros are ignored.
+For example,
+<B>10</B>
+
+is synonymous with
+<B>10.0.0.0</B>,
+
+and
+<B>128.009.000.032</B>
+
+is synonymous with
+<B>128.9.0.32</B>
+
+(the latter example is verbatim from RFC 1166).
+The result of
+<I>addrtoa</I>
+
+is always complete and does not contain leading zeros.
+<P>
+
+The letters in
+a hexadecimal address may be uppercase or lowercase or any mixture thereof.
+Use of hexadecimal addresses is
+<B>strongly</B>
+
+<B>discouraged</B>;
+
+they are included only to save hassles when dealing with
+the handful of perverted programs which already print 
+network addresses in hexadecimal.
+<P>
+
+DNS names may be complete (optionally terminated with a ``.'')
+or incomplete, and are looked up as specified by local system configuration
+(see
+<I><A HREF="resolver.5.html">resolver</A></I>(5)).
+
+The
+<I>h_addr</I>
+
+value returned by
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3)
+
+is used,
+so with current DNS implementations,
+the result when the name corresponds to more than one address is
+difficult to predict.
+Name lookup resorts to
+<I><A HREF="getnetbyname.3.html">getnetbyname</A></I>(3)
+
+only if
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3)
+
+fails.
+<P>
+
+A subnet specification is of the form <I>network</I><B>/</B><I>mask</I>.
+The
+<I>network</I>
+
+and
+<I>mask</I>
+
+can be any form acceptable to
+<I>atoaddr</I>.
+
+In addition, the
+<I>mask</I>
+
+can be a decimal integer (leading zeros ignored) giving a bit count,
+in which case
+it stands for a mask with that number of high bits on and all others off
+(e.g.,
+<B>24</B>
+
+means
+<B>255.255.255.0</B>).
+
+In any case, the mask must be contiguous
+(a sequence of high bits on and all remaining low bits off).
+As a special case, the subnet specification
+<B>%default</B>
+
+is a synonym for
+<B>0.0.0.0/0</B>.
+
+<P>
+
+<I>Atosubnet</I>
+
+ANDs the mask with the address before returning,
+so that any non-network bits in the address are turned off
+(e.g.,
+<B>10.1.2.3/24</B>
+
+is synonymous with
+<B>10.1.2.0/24</B>).
+
+<I>Subnettoa</I>
+
+generates the decimal-integer-bit-count
+form of the mask,
+with no leading zeros,
+unless the mask is non-contiguous.
+<P>
+
+The
+<I>srclen</I>
+
+parameter of
+<I>atoaddr</I>
+
+and
+<I>atosubnet</I>
+
+specifies the length of the ASCII string pointed to by
+<I>src</I>;
+
+it is an error for there to be anything else
+(e.g., a terminating NUL) within that length.
+As a convenience for cases where an entire NUL-terminated string is
+to be converted,
+a
+<I>srclen</I>
+
+value of
+<B>0</B>
+
+is taken to mean
+<B>strlen(src)</B>.
+
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of
+<I>addrtoa</I>
+
+and
+<I>subnettoa</I>
+
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+The
+<I>freeswan.h</I>
+
+header file defines constants,
+<B>ADDRTOA_BUF</B>
+
+and
+<B>SUBNETTOA_BUF</B>,
+
+which are the sizes of buffers just large enough for worst-case results.
+<P>
+
+The
+<I>format</I>
+
+parameter of
+<I>addrtoa</I>
+
+and
+<I>subnettoa</I>
+
+specifies what format is to be used for the conversion.
+The value
+<B>0</B>
+
+(not the ASCII character
+<B>'0'</B>,
+
+but a zero value)
+specifies a reasonable default,
+and is in fact the only format currently available.
+This parameter is a hedge against future needs.
+<P>
+
+The ASCII-to-binary functions return NULL for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+The binary-to-ASCII functions return
+<B>0</B>
+
+for a failure, and otherwise
+always return the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL;
+it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>atoaddr</I>
+
+are:
+empty input;
+attempt to allocate temporary storage for a very long name failed;
+name lookup failed;
+syntax error in dotted-decimal form;
+dotted-decimal component too large to fit in 8 bits.
+<P>
+
+Fatal errors in
+<I>atosubnet</I>
+
+are:
+no
+<B>/</B>
+
+in
+<I>src</I>;
+
+<I>atoaddr</I>
+
+error in conversion of
+<I>network</I>
+
+or
+<I>mask</I>;
+
+bit-count mask too big;
+mask non-contiguous.
+<P>
+
+Fatal errors in
+<I>addrtoa</I>
+
+and
+<I>subnettoa</I>
+
+are:
+unknown format.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+The interpretation of incomplete dotted-decimal addresses
+(e.g.
+<B>10/24</B>
+
+means
+<B>10.0.0.0/24</B>)
+
+differs from that of some older conversion
+functions, e.g. those of
+<I><A HREF="inet.3.html">inet</A></I>(3).
+
+The behavior of the older functions has never been
+particularly consistent or particularly useful.
+<P>
+
+Ignoring leading zeros in dotted-decimal components and bit counts
+is arguably the most useful behavior in this application,
+but it might occasionally cause confusion with the historical use of leading 
+zeros to denote octal numbers.
+<P>
+
+It is barely possible that somebody, somewhere,
+might have a legitimate use for non-contiguous subnet masks.
+<P>
+
+<I><A HREF="Getnetbyname.3.html">Getnetbyname</A></I>(3)
+
+is a historical dreg.
+<P>
+
+The restriction of ASCII-to-binary error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The ASCII-to-binary error-reporting convention lends itself
+to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = atoaddr( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_atoul.3.html b/doc/manpage.d/ipsec_atoul.3.html
new file mode 100644
index 000000000..923a16131
--- /dev/null
+++ b/doc/manpage.d/ipsec_atoul.3.html
@@ -0,0 +1,266 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ATOUL</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ATOUL</H1>
+Section: C Library Functions (3)<BR>Updated: 11 June 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec atoul, ultoa - convert unsigned-long numbers to and from ASCII
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *atoul(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int base, unsigned long *n);</B>
+
+<BR>
+
+<B>size_t ultoa(unsigned long n, int base, char *dst,</B>
+
+<BR>
+&nbsp;
+<B>size_t dstlen);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions are obsolete; see
+<I><A HREF="ipsec_ttoul.3.html">ipsec_ttoul</A></I>(3)
+
+for their replacements.
+<P>
+
+<I>Atoul</I>
+
+converts an ASCII number into a binary
+<B>unsigned long</B>
+
+value.
+<I>Ultoa</I>
+
+does the reverse conversion, back to an ASCII version.
+<P>
+
+Numbers are specified in ASCII as
+decimal (e.g.
+<B>123</B>),
+
+octal with a leading zero (e.g.
+<B>012</B>,
+
+which has value 10),
+or hexadecimal with a leading
+<B>0x</B>
+
+(e.g.
+<B>0x1f</B>,
+
+which has value 31)
+in either upper or lower case.
+<P>
+
+The
+<I>srclen</I>
+
+parameter of
+<I>atoul</I>
+
+specifies the length of the ASCII string pointed to by
+<I>src</I>;
+
+it is an error for there to be anything else
+(e.g., a terminating NUL) within that length.
+As a convenience for cases where an entire NUL-terminated string is
+to be converted,
+a
+<I>srclen</I>
+
+value of
+<B>0</B>
+
+is taken to mean
+<B>strlen(src)</B>.
+
+<P>
+
+The
+<I>base</I>
+
+parameter of
+<I>atoul</I>
+
+can be
+<B>8</B>,
+
+<B>10</B>,
+
+or
+<B>16</B>,
+
+in which case the number supplied is assumed to be of that form
+(and in the case of
+<B>16</B>,
+
+to lack any
+<B>0x</B>
+
+prefix).
+It can also be
+<B>0</B>,
+
+in which case the number is examined for a leading zero
+or a leading
+<B>0x</B>
+
+to determine its base,
+or
+<B>13</B>
+
+(halfway between 10 and 16),
+which has the same effect as
+<B>0</B>
+
+except that a non-hexadecimal
+number is considered decimal regardless of any leading zero.
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of
+<I>ultoa</I>
+
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+<P>
+
+The
+<I>base</I>
+
+parameter of
+<I>ultoa</I>
+
+must be
+<B>8</B>,
+
+<B>10</B>,
+
+or
+<B>16</B>.
+
+<P>
+
+<I>Atoul</I>
+
+returns NULL for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<I>Ultoa</I>
+
+returns the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL;
+it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="atol.3.html">atol</A>(3), <A HREF="strtoul.3.html">strtoul</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>atoul</I>
+
+are:
+empty input;
+unknown
+<I>base</I>;
+
+non-digit character found;
+number too large for an
+<B>unsigned long</B>.
+
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+There is no provision for reporting an invalid
+<I>base</I>
+
+parameter given to
+<I>ultoa</I>.
+
+<P>
+
+The restriction of error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The error-reporting convention lends itself to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = atoul( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_auto.8.html b/doc/manpage.d/ipsec_auto.8.html
new file mode 100644
index 000000000..68ca61bdc
--- /dev/null
+++ b/doc/manpage.d/ipsec_auto.8.html
@@ -0,0 +1,416 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_AUTO</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_AUTO</H1>
+Section: Maintenance Commands (8)<BR>Updated: 31 Jan 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec auto - control automatically-keyed IPsec connections
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>auto</B>
+
+[
+<B>--show</B>
+
+] [
+<B>--showonly</B>
+
+] [
+<B>--asynchronous</B>
+
+]
+<BR>
+
+&nbsp;&nbsp;&nbsp;[
+<B>--config</B>
+
+configfile
+] [
+<B>--verbose</B>
+
+]
+<BR>
+
+&nbsp;&nbsp;&nbsp;operation
+connection
+<P>
+<B>ipsec</B>
+
+<B>auto</B>
+
+[
+<B>--show</B>
+
+] [
+<B>--showonly</B>
+
+] operation
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Auto</I>
+
+manipulates automatically-keyed FreeS/WAN IPsec connections,
+setting them up and shutting them down
+based on the information in the IPsec configuration file.
+In the normal usage,
+<I>connection</I>
+
+is the name of a connection specification in the configuration file;
+<I>operation</I>
+
+is
+<B>--add</B>,
+
+<B>--delete</B>,
+
+<B>--replace</B>,
+
+<B>--up</B>,
+
+<B>--down</B>,
+
+<B>--route</B>,
+
+or
+<B>--unroute</B>.
+
+The
+<B>--ready</B>,
+
+<B>--rereadsecrets</B>,
+
+<B>--rereadgroups</B>,
+
+and
+<B>--status</B>
+
+<I>operations</I>
+
+do not take a connection name.
+<I>Auto</I>
+
+generates suitable
+commands and feeds them to a shell for execution.
+<P>
+
+The
+<B>--add</B>
+
+operation adds a connection specification to the internal database
+within
+<I>pluto</I>;
+
+it will fail if
+<I>pluto</I>
+
+already has a specification by that name.
+The
+<B>--delete</B>
+
+operation deletes a connection specification from
+<I>pluto</I>'s
+
+internal database (also tearing down any connections based on it);
+it will fail if the specification does not exist.
+The
+<B>--replace</B>
+
+operation is equivalent to
+<B>--delete</B>
+
+(if there is already a specification by the given name)
+followed by
+<B>--add</B>,
+
+and is a convenience for updating
+<I>pluto</I>'s
+
+internal specification to match an external one.
+(Note that a
+<B>--rereadsecrets</B>
+
+may also be needed.)
+The
+<B>--rereadgroups</B>
+
+operation causes any changes to the policy group files to take effect
+(this is currently a synonym for
+<B>--ready</B>,
+
+but that may change).
+None of the other operations alters the internal database.
+<P>
+
+The
+<B>--up</B>
+
+operation asks
+<I>pluto</I>
+
+to establish a connection based on an entry in its internal database.
+The
+<B>--down</B>
+
+operation tells
+<I>pluto</I>
+
+to tear down such a connection.
+<P>
+
+Normally,
+<I>pluto</I>
+
+establishes a route to the destination specified for a connection as
+part of the
+<B>--up</B>
+
+operation.
+However, the route and only the route can be established with the
+<B>--route</B>
+
+operation.
+Until and unless an actual connection is established,
+this discards any packets sent there,
+which may be preferable to having them sent elsewhere based on a more
+general route (e.g., a default route).
+<P>
+
+Normally,
+<I>pluto</I>'s
+
+route to a destination remains in place when a
+<B>--down</B>
+
+operation is used to take the connection down
+(or if connection setup, or later automatic rekeying, fails).
+This permits establishing a new connection (perhaps using a
+different specification; the route is altered as necessary)
+without having a ``window'' in which packets might go elsewhere
+based on a more general route.
+Such a route can be removed using the
+<B>--unroute</B>
+
+operation
+(and is implicitly removed by
+<B>--delete</B>).
+
+<P>
+
+The
+<B>--ready</B>
+
+operation tells
+<I>pluto</I>
+
+to listen for connection-setup requests from other hosts.
+Doing an
+<B>--up</B>
+
+operation before doing
+<B>--ready</B>
+
+on both ends is futile and will not work,
+although this is now automated as part of IPsec startup and
+should not normally be an issue.
+<P>
+
+The
+<B>--status</B>
+
+operation asks
+<I>pluto</I>
+
+for current connection status.
+The output format is ad-hoc and likely to change.
+<P>
+
+The
+<B>--rereadsecrets</B>
+
+operation tells
+<I>pluto</I>
+
+to re-read the
+<I>/etc/ipsec.secrets</I>
+
+secret-keys file,
+which it normally reads only at startup time.
+(This is currently a synonym for
+<B>--ready</B>,
+
+but that may change.)
+<P>
+
+The
+<B>--show</B>
+
+option turns on the
+<B>-x</B>
+
+option of the shell used to execute the commands,
+so each command is shown as it is executed.
+<P>
+
+The
+<B>--showonly</B>
+
+option causes
+<I>auto</I>
+
+to show the commands it would run, on standard output,
+and not run them.
+<P>
+
+The
+<B>--asynchronous</B>
+
+option, applicable only to the
+<B>up</B>
+
+operation,
+tells
+<I>pluto</I>
+
+to attempt to establish the connection,
+but does not delay to report results.
+This is especially useful to start multiple connections in parallel
+when network links are slow.
+<P>
+
+The
+<B>--verbose</B>
+
+option instructs
+<I>auto</I>
+
+to pass through all output from
+<I><A HREF="ipsec_whack.8.html">ipsec_whack</A></I>(8),
+
+including log output that is normally filtered out as uninteresting.
+<P>
+
+The
+<B>--config</B>
+
+option specifies a non-standard location for the IPsec
+configuration file (default
+<I>/etc/ipsec.conf</I>).
+
+<P>
+
+See
+<I><A HREF="ipsec.conf.5.html">ipsec.conf</A></I>(5)
+
+for details of the configuration file.
+Apart from the basic parameters which specify the endpoints and routing
+of a connection (<B>left</B>
+and
+<B>right</B>,
+
+plus possibly
+<B>leftsubnet</B>,
+
+<B>leftnexthop</B>,
+
+<B>leftfirewall</B>,
+
+their
+<B>right</B>
+
+equivalents,
+and perhaps
+<B>type</B>),
+
+an
+<I>auto</I>
+
+connection almost certainly needs a
+<B>keyingtries</B>
+
+parameter (since the
+<B>keyingtries</B>
+
+default is poorly chosen).
+<A NAME="lbAE">&nbsp;</A>
+<H2>FILES</H2>
+
+
+
+/etc/ipsec.conf<TT>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TT>default IPSEC configuration file<BR>
+<BR>
+
+/var/run/ipsec.info<TT>&nbsp;&nbsp;&nbsp;</TT><B>%defaultroute</B> information<BR>
+<A NAME="lbAF">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.conf.5.html">ipsec.conf</A>(5), <A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_pluto.8.html">ipsec_pluto</A>(8), <A HREF="ipsec_whack.8.html">ipsec_whack</A>(8), <A HREF="ipsec_manual.8.html">ipsec_manual</A>(8)
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org">http://www.freeswan.org</A>&gt;
+by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+Although an
+<B>--up</B>
+
+operation does connection setup on both ends,
+<B>--down</B>
+
+tears only one end of the connection down
+(although the orphaned end will eventually time out).
+<P>
+
+There is no support for
+<B>passthrough</B>
+
+connections.
+<P>
+
+A connection description which uses
+<B>%defaultroute</B>
+
+for one of its
+<B>nexthop</B>
+
+parameters but not the other may be falsely
+rejected as erroneous in some circumstances.
+<P>
+
+The exit status of
+<B>--showonly</B>
+
+does not always reflect errors discovered during processing of the request.
+(This is fine for human inspection, but not so good for use in scripts.)
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">FILES</A><DD>
+<DT><A HREF="#lbAF">SEE ALSO</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_barf.8.html b/doc/manpage.d/ipsec_barf.8.html
new file mode 100644
index 000000000..e7b7200e0
--- /dev/null
+++ b/doc/manpage.d/ipsec_barf.8.html
@@ -0,0 +1,150 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_BARF</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_BARF</H1>
+Section: Maintenance Commands (8)<BR>Updated: 17 March 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec barf - spew out collected IPsec debugging information
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>barf</B>
+
+[
+<B>--short</B>
+
+]
+<P>
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Barf</I>
+
+outputs (on standard output) a collection of debugging information
+(contents of files, selections from logs, etc.)
+related to the IPsec encryption/authentication system.
+It is primarily a convenience for remote debugging,
+a single command which packages up (and labels) all information
+that might be relevant to diagnosing a problem in IPsec.
+<P>
+
+<P>
+
+The
+<B>--short</B>
+
+option limits the length of
+the log portion of
+<I>barf</I>'s
+
+output, which can otherwise be extremely voluminous
+if debug logging is turned on.
+<P>
+
+<I>Barf</I>
+
+censors its output,
+replacing keys
+and secrets with brief checksums to avoid revealing sensitive information.
+<P>
+
+Beware that the output of both commands is aimed at humans,
+not programs,
+and the output format is subject to change without warning.
+<P>
+
+<I>Barf</I>
+
+has to figure out which files in
+<I>/var/log</I>
+
+contain the IPsec log messages.
+It looks for KLIPS and general log messages first in
+<I>messages</I>
+
+and
+<I>syslog</I>,
+
+and for Pluto messages first in
+<I>secure</I>,
+
+<I>auth.log</I>,
+
+and
+<I>debug</I>.
+
+In both cases,
+if it does not find what it is looking for in one of those ``likely'' places,
+it will resort to a brute-force search of most (non-compressed) files in
+<I>/var/log</I>.
+
+<A NAME="lbAE">&nbsp;</A>
+<H2>FILES</H2>
+
+<PRE>
+/proc/net/*
+/var/log/*
+/etc/ipsec.conf
+/etc/ipsec.secrets
+</PRE>
+
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org">http://www.freeswan.org</A>&gt;
+by Henry Spencer.
+<A NAME="lbAG">&nbsp;</A>
+<H2>BUGS</H2>
+
+<I>Barf</I>
+
+uses heuristics to try to pick relevant material out of the logs,
+and relevant messages
+which are not labelled with any of the tags that
+<I>barf</I>
+
+looks for will be lost.
+We think we've eliminated the last such case, but one never knows...
+<P>
+
+Finding
+<I>updown</I>
+
+scripts (so they can be included in output) is, in general, difficult.
+<I>Barf</I>
+
+uses a very simple heuristic that is easily fooled.
+<P>
+
+The brute-force search for the right log files can get expensive on
+systems with a lot of clutter in
+<I>/var/log</I>.
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">FILES</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+<DT><A HREF="#lbAG">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_bitstomask.3.html b/doc/manpage.d/ipsec_bitstomask.3.html
new file mode 100644
index 000000000..a67a08d83
--- /dev/null
+++ b/doc/manpage.d/ipsec_bitstomask.3.html
@@ -0,0 +1,122 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_GOODMASK</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_GOODMASK</H1>
+Section: C Library Functions (3)<BR>Updated: 11 June 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec goodmask - is this Internet subnet mask a valid one?
+<BR>
+
+ipsec masktobits - convert Internet subnet mask to bit count
+<BR>
+
+ipsec bitstomask - convert bit count to Internet subnet mask
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>int goodmask(struct in_addr mask);</B>
+
+<BR>
+
+<B>int masktobits(struct in_addr mask);</B>
+
+<BR>
+
+<B>struct in_addr bitstomask(int n);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions are obsolete;
+see
+<I><A HREF="ipsec_masktocount.3.html">ipsec_masktocount</A></I>(3)
+
+for a partial replacement.
+<P>
+
+<I>Goodmask</I>
+
+reports whether the subnet
+<I>mask</I>
+
+is a valid one,
+i.e. consists of a (possibly empty) sequence of
+<B>1</B>s
+
+followed by a (possibly empty) sequence of
+<B>0</B>s.
+
+<I>Masktobits</I>
+
+takes a (valid) subnet mask and returns the number of
+<B>1</B>
+
+bits in it.
+<I>Bitstomask</I>
+
+reverses this,
+returning the subnet mask corresponding to bit count
+<I>n</I>.
+
+<P>
+
+All masks are in network byte order.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_atosubnet.3.html">ipsec_atosubnet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+<I>Masktobits</I>
+
+returns
+<B>-1</B>
+
+for an invalid mask.
+<I>Bitstomask</I>
+
+returns an all-zeros mask for a negative or out-of-range
+<I>n</I>.
+
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+The error-reporting convention of
+<I>bitstomask</I>
+
+is less than ideal;
+zero is sometimes a legitimate mask.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_broadcastof.3.html b/doc/manpage.d/ipsec_broadcastof.3.html
new file mode 100644
index 000000000..57d4a5648
--- /dev/null
+++ b/doc/manpage.d/ipsec_broadcastof.3.html
@@ -0,0 +1,107 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_SUBNETOF</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_SUBNETOF</H1>
+Section: C Library Functions (3)<BR>Updated: 11 June 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec subnetof - given Internet address and subnet mask, return subnet number
+<BR>
+
+ipsec hostof - given Internet address and subnet mask, return host part
+<BR>
+
+ipsec broadcastof - given Internet address and subnet mask, return broadcast address
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>struct in_addr subnetof(struct in_addr addr,</B>
+
+<BR>
+&nbsp;
+<B>struct in_addr mask);</B>
+
+<BR>
+
+<B>struct in_addr hostof(struct in_addr addr,</B>
+
+<BR>
+&nbsp;
+<B>struct in_addr mask);</B>
+
+<BR>
+
+<B>struct in_addr broadcastof(struct in_addr addr,</B>
+
+<BR>
+&nbsp;
+<B>struct in_addr mask);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions are obsolete; see
+<I><A HREF="ipsec_networkof.3.html">ipsec_networkof</A></I>(3)
+
+for their replacements.
+<P>
+
+<I>Subnetof</I>
+
+takes an Internet
+<I>address</I>
+
+and a subnet
+<I>mask</I>
+
+and returns the network part of the address
+(all in network byte order).
+<I>Hostof</I>
+
+similarly returns the host part, and
+<I>broadcastof</I>
+
+returns the broadcast address (all-1s convention) for the network.
+<P>
+
+These functions are provided to hide the Internet bit-munging inside
+an API, in hopes of easing the eventual transition to IPv6.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_atosubnet.3.html">ipsec_atosubnet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAG">&nbsp;</A>
+<H2>BUGS</H2>
+
+Calling functions for this is more costly than doing it yourself.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+<DT><A HREF="#lbAG">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_calcgoo.8.html b/doc/manpage.d/ipsec_calcgoo.8.html
new file mode 100644
index 000000000..8379ac6a4
--- /dev/null
+++ b/doc/manpage.d/ipsec_calcgoo.8.html
@@ -0,0 +1,78 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_CALCGOO</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_CALCGOO</H1>
+Section: Maintenance Commands (8)<BR>Updated: 8 June 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec calcgoo - calculate hex value for matching modules and kernels
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>calcgoo</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>calcgoo</I>
+
+accepts the output of 
+<B>nm -ao</B>
+
+or 
+<B>/proc/ksyms</B>
+
+and extracts a release dependant list of symbols from it. The symbols
+are processed to extract the values assigned during the MODVERSIONS 
+process. This process makes sure that Linux modules are only loaded
+on matching kernels.
+
+This routine is used to find an appropriate module to match the currently
+running kernel by _startklips.
+<A NAME="lbAE">&nbsp;</A>
+<H2>FILES</H2>
+
+<PRE>
+/proc/ksyms
+</PRE>
+
+<A NAME="lbAF">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec__startklips.8.html">ipsec__startklips</A>(8), <A HREF="genksyms.8.html">genksyms</A>(8)
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org">http://www.freeswan.org</A>&gt;
+by Michael Richardson.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">FILES</A><DD>
+<DT><A HREF="#lbAF">SEE ALSO</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_copyright_notice.3.html b/doc/manpage.d/ipsec_copyright_notice.3.html
new file mode 100644
index 000000000..c832e01f7
--- /dev/null
+++ b/doc/manpage.d/ipsec_copyright_notice.3.html
@@ -0,0 +1,94 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_VERSION</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_VERSION</H1>
+Section: C Library Functions (3)<BR>Updated: 21 Nov 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec ipsec_version_code - get IPsec version code
+<BR>
+
+ipsec ipsec_version_string - get full IPsec version string
+<BR>
+
+ipsec ipsec_copyright_notice - get IPsec copyright notice
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *ipsec_version_code(void);</B>
+
+<BR>
+
+<B>const char *ipsec_version_string(void);</B>
+
+<BR>
+
+<B>const char **ipsec_copyright_notice(void);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions provide information on version numbering and copyright
+of the Linux FreeS/WAN IPsec implementation.
+<P>
+
+<I>Ipsec_version_code</I>
+
+returns a pointer to a string constant
+containing the current IPsec version code,
+such as ``1.92'' or ``snap2001Nov19b''.
+<P>
+
+<I>Ipsec_version_string</I>
+
+returns a pointer to a string constant giving a full version identification,
+consisting of the version code preceded by a prefix identifying the software,
+e.g. ``Linux FreeS/WAN 1.92''.
+<P>
+
+<I>Ipsec_copyright_notice</I>
+
+returns a pointer to a vector of pointers,
+terminated by a
+<B>NULL</B>,
+
+which is the text of a suitable copyright notice.
+Each pointer points to a string constant (possibly empty) which is one line
+of the somewhat-verbose copyright notice.
+The strings are NUL-terminated and do not contain a newline;
+supplying suitable line termination for the output device is
+the caller's responsibility.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8)
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_datatot.3.html b/doc/manpage.d/ipsec_datatot.3.html
new file mode 100644
index 000000000..628558001
--- /dev/null
+++ b/doc/manpage.d/ipsec_datatot.3.html
@@ -0,0 +1,439 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_TTODATA</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_TTODATA</H1>
+Section: C Library Functions (3)<BR>Updated: 16 August 2003<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec ttodata, datatot - convert binary data bytes from and to text formats
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *ttodata(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int base, char *dst, size_t dstlen, size_t *lenp);</B>
+
+<BR>
+
+<B>const char *ttodatav(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int base, char *dst, size_t dstlen, size_t *lenp,</B>
+
+<BR>
+&nbsp;
+<B>char *errp, size_t errlen, int flags);</B>
+
+<BR>
+
+<B>size_t datatot(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int format, char *dst, size_t dstlen);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Ttodata</I>,
+
+<I>ttodatav</I>,
+
+and
+<I>datatot</I>
+
+convert arbitrary binary data (e.g. encryption or authentication keys)
+from and to more-or-less human-readable text formats.
+<P>
+
+Currently supported formats are hexadecimal, base64, and characters.
+<P>
+
+A hexadecimal text value begins with a
+<B>0x</B>
+
+(or
+<B>0X</B>)
+
+prefix and continues with two-digit groups
+of hexadecimal digits (0-9, and a-f or A-F),
+each group encoding the value of one binary byte, high-order digit first.
+A single
+<B>_</B>
+
+(underscore)
+between consecutive groups is ignored, permitting punctuation to improve 
+readability; doing this every eight digits seems about right.
+<P>
+
+A base64 text value begins with a
+<B>0s</B>
+
+(or
+<B>0S</B>)
+
+prefix 
+and continues with four-digit groups of base64 digits (A-Z, a-z, 0-9, +, and /),
+each group encoding the value of three binary bytes as described in
+section 6.8 of RFC 2045.
+If
+<B>flags</B>
+
+has the
+<B>TTODATAV_IGNORESPACE</B>
+
+bit on, blanks are ignore (after the prefix).
+Note that the last one or two digits of a base64 group can be
+<B>=</B>
+
+to indicate that fewer than three binary bytes are encoded.
+<P>
+
+A character text value begins with a
+<B>0t</B>
+
+(or
+<B>0T</B>)
+
+prefix
+and continues with text characters, each being the value of one binary byte. 
+<P>
+
+All these functions basically copy data from
+<I>src</I>
+
+(whose size is specified by
+<I>srclen</I>)
+
+to
+<I>dst</I>
+
+(whose size is specified by
+<I>dstlen</I>),
+
+doing the conversion en route.
+If the result will not fit in
+<I>dst</I>,
+
+it is truncated;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes of result written to
+<I>dst</I>.
+
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result bytes are written at all.
+<P>
+
+The
+<I>base</I>
+
+parameter of
+<I>ttodata</I>
+
+and
+<I>ttodatav</I>
+
+specifies what format the input is in;
+normally it should be
+<B>0</B>
+
+to signify that this gets figured out from the prefix.
+Values of
+<B>16</B>,
+
+<B>64</B>,
+
+and
+<B>256</B>
+
+respectively signify hexadecimal, base64, and character-text formats
+without prefixes.
+<P>
+
+The
+<I>format</I>
+
+parameter of
+<I>datatot</I>,
+
+a single character used as a type code,
+specifies which text format is wanted.
+The value
+<B>0</B>
+
+(not ASCII
+<B>'0'</B>,
+
+but a zero value) specifies a reasonable default.
+Other currently-supported values are:
+<DL COMPACT><DT><DD>
+<DL COMPACT>
+<DT><B>'x'</B>
+
+<DD>
+continuous lower-case hexadecimal with a
+<B>0x</B>
+
+prefix
+<DT><B>'h'</B>
+
+<DD>
+lower-case hexadecimal with a
+<B>0x</B>
+
+prefix and a
+<B>_</B>
+
+every eight digits
+<DT><B>':'</B>
+
+<DD>
+lower-case hexadecimal with no prefix and a
+<B>:</B>
+
+(colon) every two digits
+<DT><B>16</B>
+
+<DD>
+lower-case hexadecimal with no prefix or
+<B>_</B>
+
+<DT><B>'s'</B>
+
+<DD>
+continuous base64 with a
+<B>0s</B>
+
+prefix
+<DT><B>64</B>
+
+<DD>
+continuous base64 with no prefix
+</DL>
+</DL>
+
+<P>
+
+The default format is currently
+<B>'h'</B>.
+
+<P>
+
+<I>Ttodata</I>
+
+returns NULL for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+On success,
+if and only if
+<I>lenp</I>
+
+is non-NULL,
+<B>*lenp</B>
+
+is set to the number of bytes required to contain the full untruncated result.
+It is the caller's responsibility to check this against
+<I>dstlen</I>
+
+to determine whether he has obtained a complete result.
+The
+<B>*lenp</B>
+
+value is correct even if
+<I>dstlen</I>
+
+is zero, which offers a way to determine how much space would be needed
+before having to allocate any.
+<P>
+
+<I>Ttodatav</I>
+
+is just like
+<I>ttodata</I>
+
+except that in certain cases,
+if
+<I>errp</I>
+
+is non-NULL,
+the buffer pointed to by
+<I>errp</I>
+
+(whose length is given by
+<I>errlen</I>)
+
+is used to hold a more detailed error message.
+The return value is NULL for success,
+and is either
+<I>errp</I>
+
+or a pointer to a string literal for failure.
+If the size of the error-message buffer is
+inadequate for the desired message,
+<I>ttodatav</I>
+
+will fall back on returning a pointer to a literal string instead.
+The
+<I>freeswan.h</I>
+
+header file defines a constant
+<B>TTODATAV_BUF</B>
+
+which is the size of a buffer large enough for worst-case results.
+<P>
+
+The normal return value of
+<I>datatot</I>
+
+is the number of bytes required
+to contain the full untruncated result.
+It is the caller's responsibility to check this against
+<I>dstlen</I>
+
+to determine whether he has obtained a complete result.
+The return value is correct even if
+<I>dstlen</I>
+
+is zero, which offers a way to determine how much space would be needed
+before having to allocate any.
+A return value of
+<B>0</B>
+
+signals a fatal error of some kind
+(see DIAGNOSTICS).
+<P>
+
+A zero value for
+<I>srclen</I>
+
+in
+<I>ttodata</I>
+
+(but not
+<I>datatot</I>!)
+
+is synonymous with
+<B>strlen(src)</B>.
+
+A non-zero
+<I>srclen</I>
+
+in
+<I>ttodata</I>
+
+must not include the terminating NUL.
+<P>
+
+Unless
+<I>dstlen</I>
+
+is zero,
+the result supplied by
+<I>datatot</I>
+
+is always NUL-terminated,
+and its needed-size return value includes space for the terminating NUL.
+<P>
+
+Several obsolete variants of these functions
+(<I>atodata</I>,
+
+<I>datatoa</I>,
+
+<I>atobytes</I>,
+
+and
+<I>bytestoa</I>)
+
+are temporarily also supported.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="sprintf.3.html">sprintf</A>(3), <A HREF="ipsec_atoaddr.3.html">ipsec_atoaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>ttodata</I>
+
+and
+<I>ttodatav</I>
+
+are:
+unknown characters in the input;
+unknown or missing prefix;
+unknown base;
+incomplete digit group;
+non-zero padding in a base64 less-than-three-bytes digit group;
+zero-length input.
+<P>
+
+Fatal errors in
+<I>datatot</I>
+
+are:
+unknown format code;
+zero-length input.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+<I>Datatot</I>
+
+should have a format code to produce character-text output.
+<P>
+
+The
+<B>0s</B>
+
+and
+<B>0t</B>
+
+prefixes are the author's inventions and are not a standard
+of any kind.
+They have been chosen to avoid collisions with existing practice
+(some C implementations use
+<B>0b</B>
+
+for binary)
+and possible confusion with unprefixed hexadecimal.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_eroute.5.html b/doc/manpage.d/ipsec_eroute.5.html
new file mode 100644
index 000000000..158b57015
--- /dev/null
+++ b/doc/manpage.d/ipsec_eroute.5.html
@@ -0,0 +1,370 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_EROUTE</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_EROUTE</H1>
+Section: File Formats (5)<BR>Updated: 20 Sep 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec_eroute - list of existing eroutes
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>eroute</B>
+
+<P>
+
+<B>cat</B>
+
+<B>/proc/net/ipsec_eroute</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>/proc/net/ipsec_eroute</I>
+
+lists the IPSEC extended routing tables,
+which control what (if any) processing is applied
+to non-encrypted packets arriving for IPSEC processing and forwarding.
+At this point it is a read-only file.
+<P>
+
+A table entry consists of:
+<DL COMPACT>
+<DT>+<DD>
+packet count,
+<DT>+<DD>
+source address with mask,
+<DT>+<DD>
+a '-&gt;' separator for visual and automated parsing between src and dst
+<DT>+<DD>
+destination address with mask
+<DT>+<DD>
+a '=&gt;' separator for visual and automated parsing between selection
+criteria and SAID to use
+<DT>+<DD>
+SAID (Security Association IDentifier), comprised of:
+<DT>+<DD>
+protocol
+(<I>proto</I>),
+<DT>+<DD>
+address family
+(<I>af</I>),
+where '.' stands for IPv4 and ':' for IPv6
+<DT>+<DD>
+Security Parameters Index
+(<I>SPI</I>),
+<DT>+<DD>
+effective destination
+(<I>edst</I>),
+where the packet should be forwarded after processing
+(normally the other security gateway)
+together indicate which Security Association should be used to process
+the packet,
+<DT>+<DD>
+source identity text string with no whitespace, in parens,
+<DT>+<DD>
+destination identity text string with no whitespace, in parens
+</DL>
+<P>
+
+Addresses are written as IPv4 dotted quads or IPv6 coloned hex,
+protocol is one of &quot;ah&quot;, &quot;esp&quot;, &quot;comp&quot; or &quot;tun&quot;
+and
+SPIs are prefixed hexadecimal numbers where the prefix '.' is for IPv4 and the prefix ':' is for IPv6
+<P>
+
+SAIDs are written as &quot;<A HREF="mailto:protoafSPI@edst">protoafSPI@edst</A>&quot;.  There are also 5
+&quot;magic&quot; SAIDs which have special meaning:
+<DL COMPACT>
+<DT>+<DD>
+<B>%drop</B>
+
+means that matches are to be dropped
+<DT>+<DD>
+<B>%reject</B>
+
+means that matches are to be dropped and an ICMP returned, if
+possible to inform
+<DT>+<DD>
+<B>%trap</B>
+
+means that matches are to trigger an ACQUIRE message to the Key
+Management daemon(s) and a hold eroute will be put in place to
+prevent subsequent packets also triggering ACQUIRE messages.
+<DT>+<DD>
+<B>%hold</B>
+
+means that matches are to stored until the eroute is replaced or
+until that eroute gets reaped
+<DT>+<DD>
+<B>%pass</B>
+
+means that matches are to allowed to pass without IPSEC processing
+<BR>
+
+
+</DL>
+<A NAME="lbAE">&nbsp;</A>
+<H2>EXAMPLES</H2>
+
+<P>
+
+<B>1867     172.31.252.0/24    -&gt; 0.0.0.0/0          =&gt; <A HREF="mailto:tun.130@192.168.43.1">tun.130@192.168.43.1</A> </B>
+
+<BR>
+
+<B>        ()<TT>&nbsp;&nbsp;&nbsp;&nbsp;</TT>()</B>
+
+<P>
+
+means that 1,867 packets have been sent to an<BR>
+<B>eroute</B>
+
+that has been set up to protect traffic between the subnet
+<B>172.31.252.0</B>
+
+with a subnet mask of
+<B>24</B>
+
+bits and the default address/mask represented by an address of
+<B>0.0.0.0</B>
+
+with a subnet mask of
+<B>0</B>
+
+bits using the local machine as a security gateway on this end of the
+tunnel and the machine
+<B>192.168.43.1</B>
+
+on the other end of the tunnel with a Security Association IDentifier of
+<B><A HREF="mailto:tun0x130@192.168.43.1">tun0x130@192.168.43.1</A></B>
+
+which means that it is a tunnel mode connection (4, IPPROTO_IPIP) with a
+Security Parameters Index of
+<B>130</B>
+
+in hexadecimal with no identies defined for either end.
+<P>
+
+<B>125      3049:1::/64    -&gt; 0:0/0          =&gt; tun:<A HREF="mailto:130@3058">130@3058</A>:4::5<TT>&nbsp;</TT>()<TT>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TT>()</B>
+
+<P>
+
+means that 125 packets have been sent to an<BR>
+<B>eroute</B>
+
+that has been set up to protect traffic between the subnet
+<B>3049:1::</B>
+
+with a subnet mask of
+<B>64</B>
+
+bits and the default address/mask represented by an address of
+<B>0:0</B>
+
+with a subnet mask of
+<B>0</B>
+
+bits using the local machine as a security gateway on this end of the
+tunnel and the machine
+<B>3058:4::5</B>
+
+on the other end of the tunnel with a Security Association IDentifier of
+<B>tun:<A HREF="mailto:130@3058">130@3058</A>:4::5</B>
+
+which means that it is a tunnel mode connection with a
+Security Parameters Index of
+<B>130</B>
+
+in hexadecimal with no identies defined for either end.
+<P>
+
+<B>42         192.168.6.0/24     -&gt; 192.168.7.0/24     =&gt; %passthrough</B>
+
+<P>
+
+means that 42 packets have been sent to an
+<B>eroute</B>
+
+that has been set up to pass the traffic from the subnet
+<B>192.168.6.0</B>
+
+with a subnet mask of
+<B>24</B>
+
+bits and to subnet
+<B>192.168.7.0</B>
+
+with a subnet mask of
+<B>24</B>
+
+bits without any IPSEC processing with no identies defined for either end.
+<P>
+
+<B>2112     192.168.8.55/32    -&gt; 192.168.9.47/24    =&gt; %hold<TT>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TT>(east)<TT>&nbsp;&nbsp;</TT>()</B>
+
+<P>
+
+means that 2112 packets have been sent to an<BR>
+<B>eroute</B>
+
+that has been set up to hold the traffic from the host
+<B>192.168.8.55</B>
+
+and to host
+<B>192.168.9.47</B>
+
+until a key exchange from a Key Management daemon
+succeeds and puts in an SA or fails and puts in a pass
+or drop eroute depending on the default configuration with the local client
+defined as &quot;east&quot; and no identy defined for the remote end.
+<P>
+
+<B>2001     192.168.2.110/32   -&gt; 192.168.2.120/32   =&gt; </B>
+
+<BR>
+
+<B>        <A HREF="mailto:esp.e6de@192.168.2.120">esp.e6de@192.168.2.120</A><TT>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TT>()<TT>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TT>()</B>
+
+<P>
+
+means that 2001 packets have been sent to an<BR>
+<B>eroute</B>
+
+that has been set up to protect traffic between the host
+<B>192.168.2.110</B>
+
+and the host
+<B>192.168.2.120</B>
+
+using
+<B>192.168.2.110</B>
+
+as a security gateway on this end of the
+connection and the machine
+<B>192.168.2.120</B>
+
+on the other end of the connection with a Security Association IDentifier of
+<B><A HREF="mailto:esp.e6de@192.168.2.120">esp.e6de@192.168.2.120</A></B>
+
+which means that it is a transport mode connection with a Security
+Parameters Index of
+<B>e6de</B>
+
+in hexadecimal using Encapsuation Security Payload protocol (50,
+IPPROTO_ESP) with no identies defined for either end.
+<P>
+
+<B>1984     3049:1::110/128   -&gt; 3049:1::120/128   =&gt; </B>
+
+<BR>
+
+<B>        ah:<A HREF="mailto:f5ed@3049">f5ed@3049</A>:1::120<TT>&nbsp;&nbsp;&nbsp;</TT>()<TT>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TT>()</B>
+
+<P>
+
+means that 1984 packets have been sent to an<BR>
+<B>eroute</B>
+
+that has been set up to authenticate traffic between the host
+<B>3049:1::110</B>
+
+and the host
+<B>3049:1::120</B>
+
+using
+<B>3049:1::110</B>
+
+as a security gateway on this end of the
+connection and the machine
+<B>3049:1::120</B>
+
+on the other end of the connection with a Security Association IDentifier of
+<B>ah:<A HREF="mailto:f5ed@3049">f5ed@3049</A>:1::120</B>
+
+which means that it is a transport mode connection with a Security
+Parameters Index of
+<B>f5ed</B>
+
+in hexadecimal using Authentication Header protocol (51,
+IPPROTO_AH) with no identies defined for either end.
+<A NAME="lbAF">&nbsp;</A>
+<H2>FILES</H2>
+
+/proc/net/ipsec_eroute, /usr/local/bin/ipsec
+<A NAME="lbAG">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_manual.8.html">ipsec_manual</A>(8), <A HREF="ipsec_tncfg.5.html">ipsec_tncfg</A>(5), <A HREF="ipsec_spi.5.html">ipsec_spi</A>(5),
+<A HREF="ipsec_spigrp.5.html">ipsec_spigrp</A>(5), <A HREF="ipsec_klipsdebug.5.html">ipsec_klipsdebug</A>(5), <A HREF="ipsec_eroute.8.html">ipsec_eroute</A>(8), <A HREF="ipsec_version.5.html">ipsec_version</A>(5),
+<A HREF="ipsec_pf_key.5.html">ipsec_pf_key</A>(5)
+<A NAME="lbAH">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Richard Guy Briggs.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">EXAMPLES</A><DD>
+<DT><A HREF="#lbAF">FILES</A><DD>
+<DT><A HREF="#lbAG">SEE ALSO</A><DD>
+<DT><A HREF="#lbAH">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_eroute.8.html b/doc/manpage.d/ipsec_eroute.8.html
new file mode 100644
index 000000000..7489462d7
--- /dev/null
+++ b/doc/manpage.d/ipsec_eroute.8.html
@@ -0,0 +1,421 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_EROUTE</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_EROUTE</H1>
+Section: Maintenance Commands (8)<BR>Updated: 21 Jun 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec eroute - manipulate IPSEC extended routing tables
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>eroute</B>
+
+<P>
+
+<B>ipsec</B>
+
+<B>eroute</B>
+
+<B>--add</B>
+
+<B>--eraf (inet | inet6)</B>
+
+<B>--src</B>
+
+src/srcmaskbits|srcmask
+<B>--dst</B>
+
+dst/dstmaskbits|dstmask
+&lt;SAID&gt;
+<P>
+
+<B>ipsec</B>
+
+<B>eroute</B>
+
+<B>--replace</B>
+
+<B>--eraf (inet | inet6)</B>
+
+<B>--src</B>
+
+src/srcmaskbits|srcmask
+<B>--dst</B>
+
+dst/dstmaskbits|dstmask
+&lt;SAID&gt;
+<P>
+
+<B>ipsec</B>
+
+<B>eroute</B>
+
+<B>--del</B>
+
+<B>--eraf (inet | inet6)</B>
+
+<B>--src</B>
+
+src/srcmaskbits|srcmask
+<B>--dst</B>
+
+dst/dstmaskbits|dstmask
+<P>
+
+<B>ipsec</B>
+
+<B>eroute</B>
+
+<B>--clear</B>
+
+<P>
+
+<B>ipsec</B>
+
+<B>eroute</B>
+
+<B>--help</B>
+
+<P>
+
+<B>ipsec</B>
+
+<B>eroute</B>
+
+<B>--version</B>
+
+<P>
+
+Where &lt;SAID&gt; is
+<B>--af</B>
+
+(inet | inet6)
+<B>--edst</B>
+
+edst
+<B>--spi</B>
+
+spi
+<B>--proto</B>
+
+proto
+OR
+<B>--said</B>
+
+said
+OR
+<B>--said</B>
+
+<B>(%passthrough | %passthrough4 | %passthrough6)</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Eroute</I>
+
+manages the IPSEC extended routing tables,
+which control what (if any) processing is applied
+to non-encrypted packets arriving for IPSEC processing and forwarding.
+The form with no additional arguments lists the contents of
+/proc/net/ipsec_eroute.
+The
+<B>--add</B>
+
+form adds a table entry, the
+<B>--replace</B>
+
+form replaces a table entry, while the
+<B>--del</B>
+
+form deletes one.  The
+<B>--clear</B>
+
+form deletes the entire table.
+<P>
+
+A table entry consists of:
+<DL COMPACT>
+<DT>+<DD>
+source and destination addresses,
+with masks,
+for selection of packets
+<DT>+<DD>
+Security Association IDentifier, comprised of:
+<DT>+<DD>
+protocol
+(<I>proto</I>), indicating (together with the
+effective destination and the security parameters index)
+which Security Association should be used to process the packet
+<DT>+<DD>
+address family
+(<I>af</I>),
+<DT>+<DD>
+Security Parameters Index
+(<I>spi</I>), indicating (together with the
+effective destination and protocol)
+which Security Association should be used to process the packet
+(must be larger than or equal to 0x100)
+<DT>+<DD>
+effective destination
+(<I>edst</I>),
+where the packet should be forwarded after processing
+(normally the other security gateway)
+<DT>+<DD>
+OR
+<DT>+<DD>
+SAID
+(<I>said</I>), indicating 
+which Security Association should be used to process the packet
+</DL>
+<P>
+
+Addresses are written as IPv4 dotted quads or IPv6 coloned hex,
+protocol is one of &quot;ah&quot;, &quot;esp&quot;, &quot;comp&quot; or &quot;tun&quot; and SPIs are
+prefixed hexadecimal numbers where '.' represents IPv4 and ':'
+stands for IPv6.
+<P>
+
+SAIDs are written as &quot;<A HREF="mailto:protoafSPI@address">protoafSPI@address</A>&quot;.  There are also 5
+&quot;magic&quot; SAIDs which have special meaning:
+<DL COMPACT>
+<DT>+<DD>
+<B>%drop</B>
+
+means that matches are to be dropped
+<DT>+<DD>
+<B>%reject</B>
+
+means that matches are to be dropped and an ICMP returned, if
+possible to inform
+<DT>+<DD>
+<B>%trap</B>
+
+means that matches are to trigger an ACQUIRE message to the Key
+Management daemon(s) and a hold eroute will be put in place to
+prevent subsequent packets also triggering ACQUIRE messages.
+<DT>+<DD>
+<B>%hold</B>
+
+means that matches are to stored until the eroute is replaced or
+until that eroute gets reaped
+<DT>+<DD>
+<B>%pass</B>
+
+means that matches are to allowed to pass without IPSEC processing
+</DL>
+<P>
+
+The format of /proc/net/ipsec_eroute is listed in <A HREF="ipsec_eroute.5.html">ipsec_eroute</A>(5).
+<BR>
+
+
+<A NAME="lbAE">&nbsp;</A>
+<H2>EXAMPLES</H2>
+
+<P>
+
+<B>ipsec eroute --add --eraf inet --src 192.168.0.1/32 \</B>
+
+<BR>
+
+<B>   --dst 192.168.2.0/24 --af inet --edst 192.168.0.2 \</B>
+
+<BR>
+
+<B>   --spi 0x135 --proto tun</B>
+
+<P>
+
+sets up an
+<B>eroute</B>
+
+on a Security Gateway to protect traffic between the host
+<B>192.168.0.1</B>
+
+and the subnet
+<B>192.168.2.0</B>
+
+with
+<B>24</B>
+
+bits of subnet mask via Security Gateway
+<B>192.168.0.2</B>
+
+using the Security Association with address
+<B>192.168.0.2</B>,
+
+Security Parameters Index
+<B>0x135</B>
+
+and protocol
+<B>tun</B>
+
+(50, IPPROTO_ESP).
+<P>
+
+<B>ipsec eroute --add --eraf inet6 --src 3049:1::1/128 \</B>
+
+<BR>
+
+<B>   --dst 3049:2::/64 --af inet6 --edst 3049:1::2 \</B>
+
+<BR>
+
+<B>   --spi 0x145 --proto tun</B>
+
+<P>
+
+sets up an
+<B>eroute</B>
+
+on a Security Gateway to protect traffic between the host
+<B>3049:1::1</B>
+
+and the subnet
+<B>3049:2::</B>
+
+with
+<B>64</B>
+
+bits of subnet mask via Security Gateway
+<B>3049:1::2</B>
+
+using the Security Association with address
+<B>3049:1::2</B>,
+
+Security Parameters Index
+<B>0x145</B>
+
+and protocol
+<B>tun</B>
+
+(50, IPPROTO_ESP).
+<P>
+
+<B>ipsec eroute --replace --eraf inet --src company.com/24 \</B>
+
+<BR>
+
+<B>   --dst <A HREF="ftp://ftp.ngo.org">ftp.ngo.org</A>/32 --said <A HREF="mailto:tun.135@gw.ngo.org">tun.135@gw.ngo.org</A></B>
+
+<P>
+
+replaces an
+<B>eroute</B>
+
+on a Security Gateway to protect traffic between the subnet
+<B>company.com</B>
+
+with
+<B>24</B>
+
+bits of subnet mask and the host
+<B><A HREF="ftp://ftp.ngo.org">ftp.ngo.org</A></B>
+
+via Security Gateway
+<B>gw.ngo.org</B>
+
+using the Security Association with Security Association ID
+<B><A HREF="mailto:tun0x135@gw.ngo.org">tun0x135@gw.ngo.org</A></B>
+
+<P>
+
+<B>ipsec eroute --del --eraf inet --src company.com/24 \</B>
+
+<BR>
+
+<B>   --dst <A HREF="http://www.ietf.org">www.ietf.org</A>/32 --said %passthrough4</B>
+
+<P>
+
+deletes an
+<B>eroute</B>
+
+on a Security Gateway that allowed traffic between the subnet
+<B>company.com</B>
+
+with
+<B>24</B>
+
+bits of subnet mask and the host
+<B><A HREF="http://www.ietf.org">www.ietf.org</A></B>
+
+to pass in the clear, unprocessed.
+<A NAME="lbAF">&nbsp;</A>
+<H2>FILES</H2>
+
+/proc/net/ipsec_eroute, /usr/local/bin/ipsec
+<A NAME="lbAG">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_manual.8.html">ipsec_manual</A>(8), <A HREF="ipsec_tncfg.8.html">ipsec_tncfg</A>(8), <A HREF="ipsec_spi.8.html">ipsec_spi</A>(8),
+<A HREF="ipsec_spigrp.8.html">ipsec_spigrp</A>(8), <A HREF="ipsec_klipsdebug.8.html">ipsec_klipsdebug</A>(8), <A HREF="ipsec_eroute.5.html">ipsec_eroute</A>(5)
+<A NAME="lbAH">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Richard Guy Briggs.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">EXAMPLES</A><DD>
+<DT><A HREF="#lbAF">FILES</A><DD>
+<DT><A HREF="#lbAG">SEE ALSO</A><DD>
+<DT><A HREF="#lbAH">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_goodmask.3.html b/doc/manpage.d/ipsec_goodmask.3.html
new file mode 100644
index 000000000..a67a08d83
--- /dev/null
+++ b/doc/manpage.d/ipsec_goodmask.3.html
@@ -0,0 +1,122 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_GOODMASK</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_GOODMASK</H1>
+Section: C Library Functions (3)<BR>Updated: 11 June 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec goodmask - is this Internet subnet mask a valid one?
+<BR>
+
+ipsec masktobits - convert Internet subnet mask to bit count
+<BR>
+
+ipsec bitstomask - convert bit count to Internet subnet mask
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>int goodmask(struct in_addr mask);</B>
+
+<BR>
+
+<B>int masktobits(struct in_addr mask);</B>
+
+<BR>
+
+<B>struct in_addr bitstomask(int n);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions are obsolete;
+see
+<I><A HREF="ipsec_masktocount.3.html">ipsec_masktocount</A></I>(3)
+
+for a partial replacement.
+<P>
+
+<I>Goodmask</I>
+
+reports whether the subnet
+<I>mask</I>
+
+is a valid one,
+i.e. consists of a (possibly empty) sequence of
+<B>1</B>s
+
+followed by a (possibly empty) sequence of
+<B>0</B>s.
+
+<I>Masktobits</I>
+
+takes a (valid) subnet mask and returns the number of
+<B>1</B>
+
+bits in it.
+<I>Bitstomask</I>
+
+reverses this,
+returning the subnet mask corresponding to bit count
+<I>n</I>.
+
+<P>
+
+All masks are in network byte order.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_atosubnet.3.html">ipsec_atosubnet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+<I>Masktobits</I>
+
+returns
+<B>-1</B>
+
+for an invalid mask.
+<I>Bitstomask</I>
+
+returns an all-zeros mask for a negative or out-of-range
+<I>n</I>.
+
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+The error-reporting convention of
+<I>bitstomask</I>
+
+is less than ideal;
+zero is sometimes a legitimate mask.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_hostof.3.html b/doc/manpage.d/ipsec_hostof.3.html
new file mode 100644
index 000000000..57d4a5648
--- /dev/null
+++ b/doc/manpage.d/ipsec_hostof.3.html
@@ -0,0 +1,107 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_SUBNETOF</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_SUBNETOF</H1>
+Section: C Library Functions (3)<BR>Updated: 11 June 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec subnetof - given Internet address and subnet mask, return subnet number
+<BR>
+
+ipsec hostof - given Internet address and subnet mask, return host part
+<BR>
+
+ipsec broadcastof - given Internet address and subnet mask, return broadcast address
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>struct in_addr subnetof(struct in_addr addr,</B>
+
+<BR>
+&nbsp;
+<B>struct in_addr mask);</B>
+
+<BR>
+
+<B>struct in_addr hostof(struct in_addr addr,</B>
+
+<BR>
+&nbsp;
+<B>struct in_addr mask);</B>
+
+<BR>
+
+<B>struct in_addr broadcastof(struct in_addr addr,</B>
+
+<BR>
+&nbsp;
+<B>struct in_addr mask);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions are obsolete; see
+<I><A HREF="ipsec_networkof.3.html">ipsec_networkof</A></I>(3)
+
+for their replacements.
+<P>
+
+<I>Subnetof</I>
+
+takes an Internet
+<I>address</I>
+
+and a subnet
+<I>mask</I>
+
+and returns the network part of the address
+(all in network byte order).
+<I>Hostof</I>
+
+similarly returns the host part, and
+<I>broadcastof</I>
+
+returns the broadcast address (all-1s convention) for the network.
+<P>
+
+These functions are provided to hide the Internet bit-munging inside
+an API, in hopes of easing the eventual transition to IPv6.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_atosubnet.3.html">ipsec_atosubnet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAG">&nbsp;</A>
+<H2>BUGS</H2>
+
+Calling functions for this is more costly than doing it yourself.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+<DT><A HREF="#lbAG">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_ikeping.8.html b/doc/manpage.d/ipsec_ikeping.8.html
new file mode 100644
index 000000000..03ed961f3
--- /dev/null
+++ b/doc/manpage.d/ipsec_ikeping.8.html
@@ -0,0 +1,137 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_IKEPING</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_IKEPING</H1>
+Section: Maintenance Commands (8)<BR>Updated: 23 Feb 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec ikeping - send/receive ISAKMP/IKE echo requests/replies
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>ikeping</B>
+
+[
+<B>--listen</B>
+
+] [
+<B>--verbose</B>
+
+] [
+<B>--wait </B>
+
+time ] [
+<B>--exchangenum </B>
+
+num ] [
+<B>--ikeport </B>
+
+localport ] [
+<B>--ikeaddress </B>
+
+address ] [ 
+<B>--inet</B>
+
+] [
+<B>--inet6</B>
+
+] destaddr[/dstport] ...
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Ikeping</I>
+
+sends and receives ISAKMP/IKE echo request and echo reply packets. These
+packets are intended for diagnostics purposes, in a manner similar to 
+<I><A HREF="ping.8.html">ping</A></I>(8)
+
+does for ICMP echo request/reply packets.
+<P>
+
+At the time of this writing, the ISAKMP echo request/reply exchange is still
+an internet-draft, and is therefore completely non-standard.
+<P>
+
+<I>Ikeping</I>
+
+will bind to the local address given by 
+<B>--ikeaddress</B>
+
+and the port number given by
+<B>--ikeport</B>
+
+defaulting to the wildcard address and the ISAKMP port 500. An ISAKMP
+exchange of type 244 (a private use number) is sent to each of the
+address/ports listed on the command line. The exchange number may be
+overridden by the  
+<B>--exchangenum </B>
+
+option.
+<P>
+
+<I>Ikeping</I>
+
+then listens for replies, printing them as they are received. Replies
+are of exchange type 245 or the specified exchange number plus 1.
+<I>Ikeping </I>
+
+will keep listening until it either receives as many echo responses as it sent,
+or until the timeout period (10 seconds) has been reached. Receipt of a
+packet will reset the timer. The 
+<B>--wait</B>
+
+option can be used to specify a different timeout period. 
+<P>
+
+If the 
+<B>--listen</B>
+
+option is given, then 
+<I>ikeping</I>
+
+will not send any packets. Instead, it will listen for them and reply to
+each request received.
+<A NAME="lbAE">&nbsp;</A>
+<H2>FILES</H2>
+
+no external files
+<A NAME="lbAF">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ping.8.html">ping</A>(8), <A HREF="ipsec_pluto.8.html">ipsec_pluto</A>(8)
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org">http://www.freeswan.org</A>&gt;
+by Michael Richardson.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">FILES</A><DD>
+<DT><A HREF="#lbAF">SEE ALSO</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_initaddr.3.html b/doc/manpage.d/ipsec_initaddr.3.html
new file mode 100644
index 000000000..ca1f857e7
--- /dev/null
+++ b/doc/manpage.d/ipsec_initaddr.3.html
@@ -0,0 +1,232 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_INITADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_INITADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 11 Sept 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec initaddr - initialize an ip_address
+<BR>
+
+ipsec addrtypeof - get address type of an ip_address
+<BR>
+
+ipsec addrlenof - get length of address within an ip_address
+<BR>
+
+ipsec addrbytesof - get copy of address within an ip_address
+<BR>
+
+ipsec addrbytesptr - get pointer to address within an ip_address
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *initaddr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int addrtypeof(const ip_address *src);</B>
+
+<BR>
+
+<B>size_t addrlenof(const ip_address *src);</B>
+
+<BR>
+
+<B>size_t addrbytesof(const ip_address *src,</B>
+
+<BR>
+&nbsp;
+<B>unsigned char *dst, size_t dstlen);</B>
+
+<BR>
+
+<B>size_t addrbytesptr(const ip_address *src,</B>
+
+<BR>
+&nbsp;
+<B>const unsigned char **dst);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+library uses an internal type
+<I>ip_address</I>
+
+to contain one of the (currently two) types of IP address.
+These functions provide basic tools for creating and examining this type.
+<P>
+
+<I>Initaddr</I>
+
+initializes a variable
+<I>*dst</I>
+
+of type
+<I>ip_address</I>
+
+from an address
+(in network byte order,
+indicated by a pointer
+<I>src</I>
+
+and a length
+<I>srclen</I>)
+
+and an address family
+<I>af</I>
+
+(typically
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>).
+
+The length must be consistent with the address family.
+<P>
+
+<I>Addrtypeof</I>
+
+returns the address type of an address,
+normally
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>.
+
+(The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file arranges to include the necessary headers for these
+names to be known.)
+<P>
+
+<I>Addrlenof</I>
+
+returns the size (in bytes) of the address within an
+<I>ip_address</I>,
+
+to permit storage allocation etc.
+<P>
+
+<I>Addrbytesof</I>
+
+copies the address within the
+<I>ip_address</I>
+
+<I>src</I>
+
+to the buffer indicated by the pointer
+<I>dst</I>
+
+and the length
+<I>dstlen</I>,
+
+and returns the address length (in bytes).
+If the address will not fit,
+as many bytes as will fit are copied;
+the returned length is still the full length.
+It is the caller's responsibility to check the
+returned value to ensure that there was enough room.
+<P>
+
+<I>Addrbytesptr</I>
+
+sets
+<I>*dst</I>
+
+to a pointer to the internal address within the
+<I>ip_address</I>,
+
+and returns the address length (in bytes).
+If
+<I>dst</I>
+
+is
+<B>NULL</B>,
+
+it just returns the address length.
+The pointer points to
+<B>const</B>
+
+to discourage misuse.
+<P>
+
+<I>Initaddr</I>
+
+returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<P>
+
+The functions which return
+<I>size_t</I>
+
+return
+<B>0</B>
+
+for a failure.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_ttoaddr.3.html">ipsec_ttoaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+An unknown address family is a fatal error for any of these functions
+except
+<I>addrtypeof</I>.
+
+An address-size mismatch is a fatal error for
+<I>initaddr</I>.
+
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+<I>Addrtypeof</I>
+
+should probably have been named
+<I>addrfamilyof</I>.
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_initsaid.3.html b/doc/manpage.d/ipsec_initsaid.3.html
new file mode 100644
index 000000000..2ba79a8ac
--- /dev/null
+++ b/doc/manpage.d/ipsec_initsaid.3.html
@@ -0,0 +1,453 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_TTOSA</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_TTOSA</H1>
+Section: C Library Functions (3)<BR>Updated: 26 Nov 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec ttosa, satot - convert IPsec Security Association IDs to and from text
+<BR>
+
+ipsec initsaid - initialize an SA ID
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>typedef struct {</B>
+
+<BR>
+&nbsp;
+<B>ip_address dst;</B>
+
+<BR>
+&nbsp;
+<B>ipsec_spi_t spi;</B>
+
+<BR>
+&nbsp;
+<B>int proto;</B>
+
+<BR>
+
+<B>} ip_said;</B>
+
+<P>
+<B>const char *ttosa(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>ip_said *sa);</B>
+
+<BR>
+
+<B>size_t satot(const ip_said *sa, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<BR>
+
+<B>void initsaid(const ip_address *addr, ipsec_spi_t spi,</B>
+
+<BR>
+&nbsp;
+<B>int proto, ip_said *dst);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Ttosa</I>
+
+converts an ASCII Security Association (SA) specifier into an
+<B>ip_said</B>
+
+structure (containing
+a destination-host address
+in network byte order,
+an SPI number in network byte order, and
+a protocol code).
+<I>Satot</I>
+
+does the reverse conversion, back to a text SA specifier.
+<I>Initsaid</I>
+
+initializes an
+<B>ip_said</B>
+
+from separate items of information.
+<P>
+
+An SA is specified in text with a mail-like syntax, e.g.
+<B><A HREF="mailto:esp.5a7@1.2.3.4">esp.5a7@1.2.3.4</A></B>.
+
+An SA specifier contains
+a protocol prefix (currently
+<B>ah</B>,
+
+<B>esp</B>,
+
+<B>tun</B>,
+
+<B>comp</B>,
+
+or
+<B>int</B>),
+
+a single character indicating the address family
+(<B>.</B>
+
+for IPv4,
+<B>:</B>
+
+for IPv6),
+an unsigned integer SPI number in hexadecimal (with no
+<B>0x</B>
+
+prefix),
+and an IP address.
+The IP address can be any form accepted by
+<I><A HREF="ipsec_ttoaddr.3.html">ipsec_ttoaddr</A></I>(3),
+
+e.g. dotted-decimal IPv4 address,
+colon-hex IPv6 address,
+or DNS name.
+<P>
+
+As a special case, the SA specifier
+<B>%passthrough4</B>
+
+or
+<B>%passthrough6</B>
+
+signifies the special SA used to indicate that packets should be
+passed through unaltered.
+(At present, these are synonyms for
+<B><A HREF="mailto:tun.0@0.0.0.0">tun.0@0.0.0.0</A></B>
+
+and
+<B>tun:0@::</B>
+
+respectively,
+but that is subject to change without notice.)
+<B>%passthrough</B>
+
+is a historical synonym for
+<B>%passthrough4</B>.
+
+These forms are known to both
+<I>ttosa</I>
+
+and
+<I>satot</I>,
+
+so the internal representation is never visible.
+<P>
+
+Similarly, the SA specifiers
+<B>%pass</B>,
+
+<B>%drop</B>,
+
+<B>%reject</B>,
+
+<B>%hold</B>,
+
+<B>%trap</B>,
+
+and
+<B>%trapsubnet</B>
+
+signify special ``magic'' SAs used to indicate that packets should be
+passed, dropped, rejected (dropped with ICMP notification),
+held,
+and trapped (sent up to
+<I><A HREF="ipsec_pluto.8.html">ipsec_pluto</A></I>(8),
+
+with either of two forms of
+<B>%hold</B>
+
+automatically installed)
+respectively.
+These forms too are known to both routines,
+so the internal representation of the magic SAs should never be visible.
+<P>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file supplies the
+<B>ip_said</B>
+
+structure, as well as a data type
+<B>ipsec_spi_t</B>
+
+which is an unsigned 32-bit integer.
+(There is no consistency between kernel and user on what such a type
+is called, hence the header hides the differences.)
+<P>
+
+The protocol code uses the same numbers that IP does.
+For user convenience, given the difficulty in acquiring the exact set of
+protocol names used by the kernel,
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+defines the names
+<B>SA_ESP</B>,
+
+<B>SA_AH</B>,
+
+<B>SA_IPIP</B>,
+
+and
+<B>SA_COMP</B>
+
+to have the same values as the kernel names
+<B>IPPROTO_ESP</B>,
+
+<B>IPPROTO_AH</B>,
+
+<B>IPPROTO_IPIP</B>,
+
+and
+<B>IPPROTO_COMP</B>.
+
+<P>
+
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+also defines
+<B>SA_INT</B>
+
+to have the value
+<B>61</B>
+
+(reserved by IANA for ``any host internal protocol'')
+and
+<B>SPI_PASS</B>,
+
+<B>SPI_DROP</B>,
+
+<B>SPI_REJECT</B>,
+
+<B>SPI_HOLD</B>,
+
+and
+<B>SPI_TRAP</B>
+
+to have the values 256-260 (in <I>host</I> byte order) respectively.
+These are used in constructing the magic SAs
+(which always have address
+<B>0.0.0.0</B>).
+
+<P>
+
+If
+<I>satot</I>
+
+encounters an unknown protocol code, e.g. 77,
+it yields output using a prefix
+showing the code numerically, e.g. ``unk77''.
+This form is
+<I>not</I>
+
+recognized by
+<I>ttosa</I>.
+
+<P>
+
+The
+<I>srclen</I>
+
+parameter of
+<I>ttosa</I>
+
+specifies the length of the string pointed to by
+<I>src</I>;
+
+it is an error for there to be anything else
+(e.g., a terminating NUL) within that length.
+As a convenience for cases where an entire NUL-terminated string is
+to be converted,
+a
+<I>srclen</I>
+
+value of
+<B>0</B>
+
+is taken to mean
+<B>strlen(src)</B>.
+
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of
+<I>satot</I>
+
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file defines a constant,
+<B>SATOT_BUF</B>,
+
+which is the size of a buffer just large enough for worst-case results.
+<P>
+
+The
+<I>format</I>
+
+parameter of
+<I>satot</I>
+
+specifies what format is to be used for the conversion.
+The value
+<B>0</B>
+
+(not the ASCII character
+<B>'0'</B>,
+
+but a zero value)
+specifies a reasonable default
+(currently
+lowercase protocol prefix, lowercase hexadecimal SPI,
+dotted-decimal or colon-hex address).
+The value
+<B>'f'</B>
+
+is similar except that the SPI is padded with
+<B>0</B>s
+
+to a fixed 32-bit width, to ease aligning displayed tables.
+<P>
+
+<I>Ttosa</I>
+
+returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<I>Satot</I>
+
+returns
+<B>0</B>
+
+for a failure, and otherwise
+always returns the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL;
+it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred.
+<P>
+
+There is also, temporarily, support for some obsolete
+forms of SA specifier which lack the address-family indicator.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec_ttoul.3.html">ipsec_ttoul</A>(3), <A HREF="ipsec_ttoaddr.3.html">ipsec_ttoaddr</A>(3), <A HREF="ipsec_samesaid.3.html">ipsec_samesaid</A>(3), <A HREF="inet.3.html">inet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>ttosa</I>
+
+are:
+empty input;
+input too small to be a legal SA specifier;
+no
+<B>@</B>
+
+in input;
+unknown protocol prefix;
+conversion error in
+<I>ttoul</I>
+
+or
+<I>ttoaddr</I>.
+
+<P>
+
+Fatal errors in
+<I>satot</I>
+
+are:
+unknown format.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+The restriction of text-to-binary error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The text-to-binary error-reporting convention lends itself
+to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = ttosa( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_initsubnet.3.html b/doc/manpage.d/ipsec_initsubnet.3.html
new file mode 100644
index 000000000..e442a9100
--- /dev/null
+++ b/doc/manpage.d/ipsec_initsubnet.3.html
@@ -0,0 +1,238 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_INITSUBNET</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_INITSUBNET</H1>
+Section: C Library Functions (3)<BR>Updated: 12 March 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec initsubnet - initialize an ip_subnet
+<BR>
+
+ipsec addrtosubnet - initialize a singleton ip_subnet
+<BR>
+
+ipsec subnettypeof - get address type of an ip_subnet
+<BR>
+
+ipsec masktocount - convert subnet mask to bit count
+<BR>
+
+ipsec networkof - get base address of an ip_subnet
+<BR>
+
+ipsec maskof - get subnet mask of an ip_subnet
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *initsubnet(const ip_address *addr,</B>
+
+<BR>
+&nbsp;
+<B>int maskbits, int clash, ip_subnet *dst);</B>
+
+<BR>
+
+<B>const char *addrtosubnet(const ip_address *addr,</B>
+
+<BR>
+&nbsp;
+<B>ip_subnet *dst);</B>
+
+<P>
+<B>int subnettypeof(const ip_subnet *src);</B>
+
+<BR>
+
+<B>int masktocount(const ip_address *src);</B>
+
+<BR>
+
+<B>void networkof(const ip_subnet *src, ip_address *dst);</B>
+
+<BR>
+
+<B>void maskof(const ip_subnet *src, ip_address *dst);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+library uses an internal type
+<I>ip_subnet</I>
+
+to contain a description of an IP subnet
+(base address plus mask).
+These functions provide basic tools for creating and examining this type.
+<P>
+
+<I>Initsubnet</I>
+
+initializes a variable
+<I>*dst</I>
+
+of type
+<I>ip_subnet</I>
+
+from a base address and
+a count of mask bits.
+The
+<I>clash</I>
+
+parameter specifies what to do if the base address includes
+<B>1</B>
+
+bits outside the prefix specified by the mask
+(that is, in the ``host number'' part of the address):
+<DL COMPACT><DT><DD>
+<DL COMPACT>
+<DT>'0'<DD>
+zero out host-number bits
+<DT>'x'<DD>
+non-zero host-number bits are an error
+</DL>
+</DL>
+
+<P>
+
+<I>Initsubnet</I>
+
+returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<P>
+
+<I>Addrtosubnet</I>
+
+initializes an
+<I>ip_subnet</I>
+
+variable
+<I>*dst</I>
+
+to a ``singleton subnet'' containing the single address
+<I>*addr</I>.
+
+It returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure.
+<P>
+
+<I>Subnettypeof</I>
+
+returns the address type of a subnet,
+normally
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>.
+
+(The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file arranges to include the necessary headers for these
+names to be known.)
+<P>
+
+<I>Masktocount</I>
+
+converts a subnet mask, expressed as an address, to a bit count
+suitable for use with
+<I>initsubnet</I>.
+
+It returns
+<B>-1</B>
+
+for error; see DIAGNOSTICS.
+<P>
+
+<I>Networkof</I>
+
+fills in
+<I>*dst</I>
+
+with the base address of subnet
+<I>src</I>.
+
+<P>
+
+<I>Maskof</I>
+
+fills in
+<I>*dst</I>
+
+with the subnet mask of subnet
+<I>src</I>,
+
+expressed as an address.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_ttosubnet.3.html">ipsec_ttosubnet</A>(3), <A HREF="ipsec_rangetosubnet.3.html">ipsec_rangetosubnet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>initsubnet</I>
+
+are:
+unknown address family;
+unknown
+<I>clash</I>
+
+value;
+impossible mask bit count;
+non-zero host-number bits and
+<I>clash</I>
+
+is
+<B>'x'</B>.
+
+Fatal errors in
+<I>addrtosubnet</I>
+
+are:
+unknown address family.
+Fatal errors in
+<I>masktocount</I>
+
+are:
+unknown address family;
+mask bits not contiguous.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_isanyaddr.3.html b/doc/manpage.d/ipsec_isanyaddr.3.html
new file mode 100644
index 000000000..974236005
--- /dev/null
+++ b/doc/manpage.d/ipsec_isanyaddr.3.html
@@ -0,0 +1,166 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ANYADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ANYADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 8 Sept 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec anyaddr - get &quot;any&quot; address
+<BR>
+
+ipsec isanyaddr - test address for equality to &quot;any&quot; address
+<BR>
+
+ipsec unspecaddr - get &quot;unspecified&quot; address
+<BR>
+
+ipsec isunspecaddr - test address for equality to &quot;unspecified&quot; address
+<BR>
+
+ipsec loopbackaddr - get loopback address
+<BR>
+
+ipsec isloopbackaddr - test address for equality to loopback address
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *anyaddr(int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int isanyaddr(const ip_address *src);</B>
+
+<BR>
+
+<B>const char *unspecaddr(int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int isunspecaddr(const ip_address *src);</B>
+
+<BR>
+
+<B>const char *loopbackaddr(int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int isloopbackaddr(const ip_address *src);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions fill in, and test for, special values of the
+<I>ip_address</I>
+
+type.
+<P>
+
+<I>Anyaddr</I>
+
+fills in the destination
+<I>*dst</I>
+
+with the ``any'' address of address family
+<I>af</I>
+
+(normally
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>).
+
+The IPv4 ``any'' address is the one embodied in the old
+<B>INADDR_ANY</B>
+
+macro.
+<P>
+
+<I>Isanyaddr</I>
+
+returns
+<B>1</B>
+
+if the
+<I>src</I>
+
+address equals the ``any'' address,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+Similarly,
+<I>unspecaddr</I>
+
+supplies, and
+<I>isunspecaddr</I>
+
+tests for,
+the ``unspecified'' address,
+which may be the same as the ``any'' address.
+<P>
+
+Similarly,
+<I>loopbackaddr</I>
+
+supplies, and
+<I>islookbackaddr</I>
+
+tests for,
+the loopback address.
+<P>
+
+<I>Anyaddr</I>,
+
+<I>unspecaddr</I>,
+
+and
+<I>loopbackaddr</I>
+
+return
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_addrtot.3.html">ipsec_addrtot</A>(3), <A HREF="ipsec_sameaddr.3.html">ipsec_sameaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in the address-supplying functions are:
+unknown address family.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_isloopbackaddr.3.html b/doc/manpage.d/ipsec_isloopbackaddr.3.html
new file mode 100644
index 000000000..974236005
--- /dev/null
+++ b/doc/manpage.d/ipsec_isloopbackaddr.3.html
@@ -0,0 +1,166 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ANYADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ANYADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 8 Sept 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec anyaddr - get &quot;any&quot; address
+<BR>
+
+ipsec isanyaddr - test address for equality to &quot;any&quot; address
+<BR>
+
+ipsec unspecaddr - get &quot;unspecified&quot; address
+<BR>
+
+ipsec isunspecaddr - test address for equality to &quot;unspecified&quot; address
+<BR>
+
+ipsec loopbackaddr - get loopback address
+<BR>
+
+ipsec isloopbackaddr - test address for equality to loopback address
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *anyaddr(int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int isanyaddr(const ip_address *src);</B>
+
+<BR>
+
+<B>const char *unspecaddr(int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int isunspecaddr(const ip_address *src);</B>
+
+<BR>
+
+<B>const char *loopbackaddr(int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int isloopbackaddr(const ip_address *src);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions fill in, and test for, special values of the
+<I>ip_address</I>
+
+type.
+<P>
+
+<I>Anyaddr</I>
+
+fills in the destination
+<I>*dst</I>
+
+with the ``any'' address of address family
+<I>af</I>
+
+(normally
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>).
+
+The IPv4 ``any'' address is the one embodied in the old
+<B>INADDR_ANY</B>
+
+macro.
+<P>
+
+<I>Isanyaddr</I>
+
+returns
+<B>1</B>
+
+if the
+<I>src</I>
+
+address equals the ``any'' address,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+Similarly,
+<I>unspecaddr</I>
+
+supplies, and
+<I>isunspecaddr</I>
+
+tests for,
+the ``unspecified'' address,
+which may be the same as the ``any'' address.
+<P>
+
+Similarly,
+<I>loopbackaddr</I>
+
+supplies, and
+<I>islookbackaddr</I>
+
+tests for,
+the loopback address.
+<P>
+
+<I>Anyaddr</I>,
+
+<I>unspecaddr</I>,
+
+and
+<I>loopbackaddr</I>
+
+return
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_addrtot.3.html">ipsec_addrtot</A>(3), <A HREF="ipsec_sameaddr.3.html">ipsec_sameaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in the address-supplying functions are:
+unknown address family.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_isunspecaddr.3.html b/doc/manpage.d/ipsec_isunspecaddr.3.html
new file mode 100644
index 000000000..974236005
--- /dev/null
+++ b/doc/manpage.d/ipsec_isunspecaddr.3.html
@@ -0,0 +1,166 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ANYADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ANYADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 8 Sept 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec anyaddr - get &quot;any&quot; address
+<BR>
+
+ipsec isanyaddr - test address for equality to &quot;any&quot; address
+<BR>
+
+ipsec unspecaddr - get &quot;unspecified&quot; address
+<BR>
+
+ipsec isunspecaddr - test address for equality to &quot;unspecified&quot; address
+<BR>
+
+ipsec loopbackaddr - get loopback address
+<BR>
+
+ipsec isloopbackaddr - test address for equality to loopback address
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *anyaddr(int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int isanyaddr(const ip_address *src);</B>
+
+<BR>
+
+<B>const char *unspecaddr(int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int isunspecaddr(const ip_address *src);</B>
+
+<BR>
+
+<B>const char *loopbackaddr(int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int isloopbackaddr(const ip_address *src);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions fill in, and test for, special values of the
+<I>ip_address</I>
+
+type.
+<P>
+
+<I>Anyaddr</I>
+
+fills in the destination
+<I>*dst</I>
+
+with the ``any'' address of address family
+<I>af</I>
+
+(normally
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>).
+
+The IPv4 ``any'' address is the one embodied in the old
+<B>INADDR_ANY</B>
+
+macro.
+<P>
+
+<I>Isanyaddr</I>
+
+returns
+<B>1</B>
+
+if the
+<I>src</I>
+
+address equals the ``any'' address,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+Similarly,
+<I>unspecaddr</I>
+
+supplies, and
+<I>isunspecaddr</I>
+
+tests for,
+the ``unspecified'' address,
+which may be the same as the ``any'' address.
+<P>
+
+Similarly,
+<I>loopbackaddr</I>
+
+supplies, and
+<I>islookbackaddr</I>
+
+tests for,
+the loopback address.
+<P>
+
+<I>Anyaddr</I>,
+
+<I>unspecaddr</I>,
+
+and
+<I>loopbackaddr</I>
+
+return
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_addrtot.3.html">ipsec_addrtot</A>(3), <A HREF="ipsec_sameaddr.3.html">ipsec_sameaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in the address-supplying functions are:
+unknown address family.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:17 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_keyblobtoid.3.html b/doc/manpage.d/ipsec_keyblobtoid.3.html
new file mode 100644
index 000000000..109cfafa7
--- /dev/null
+++ b/doc/manpage.d/ipsec_keyblobtoid.3.html
@@ -0,0 +1,174 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_KEYBLOBTOID</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_KEYBLOBTOID</H1>
+Section: C Library Functions (3)<BR>Updated: 25 March 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec keyblobtoid, splitkeytoid - generate key IDs from RSA keys
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>size_t keyblobtoid(const unsigned char *blob,</B>
+
+<BR>
+&nbsp;
+<B>size_t bloblen, char *dst, size_t dstlen);</B>
+
+<BR>
+
+<B>size_t splitkeytoid(const unsigned char *e, size_t elen,</B>
+
+<BR>
+&nbsp;
+<B>const unsigned char *m, size_t mlen, char *dst,</B>
+
+<BR>
+&nbsp;
+<B>size_t dstlen);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Keyblobtoid</I>
+
+and
+<I>splitkeytoid</I>
+
+generate
+key IDs
+from RSA keys,
+for use in messages and reporting,
+writing the result to
+<I>dst</I>.
+
+A
+<I>key ID</I>
+
+is a short ASCII string identifying a key;
+currently it is just the first nine characters of the base64
+encoding of the RFC 2537/3110 ``byte blob'' representation of the key.
+(Beware that no finite key ID can be collision-proof:
+there is always some small chance of two random keys having the
+same ID.)
+<P>
+
+<I>Keyblobtoid</I>
+
+generates a key ID from a key which is already in the form of an
+RFC 2537/3110 binary key
+<I>blob</I>
+
+(encoded exponent length, exponent, modulus).
+<P>
+
+<I>Splitkeytoid</I>
+
+generates a key ID from a key given in the form of a separate
+(binary) exponent
+<I>e</I>
+
+and modulus
+<I>m</I>.
+
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of either
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+The
+<I>freeswan.h</I>
+
+header file defines a constant
+<B>KEYID_BUF</B>
+
+which is the size of a buffer large enough for worst-case results.
+<P>
+
+Both functions return
+<B>0</B>
+
+for a failure, and otherwise
+always return the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL;
+it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred.
+
+With keys generated by
+<I><A HREF="ipsec_rsasigkey.3.html">ipsec_rsasigkey</A></I>(3),
+
+the first two base64 digits are always the same,
+and the third carries only about one bit of information.
+It's worse with keys using longer fixed exponents,
+e.g. the 24-bit exponent that's common in X.509 certificates.
+However, being able to relate key IDs to the full
+base64 text form of keys by eye is sufficiently useful that this
+waste of space seems justifiable.
+The choice of nine digits is a compromise between bulk and
+probability of collision.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+RFC 3110,
+<I>RSA/SHA-1 SIGs and RSA KEYs in the Domain Name System (DNS)</I>,
+Eastlake, 2001
+(superseding the older but better-known RFC 2537).
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors are:
+key too short to supply enough bits to construct a complete key ID
+(almost certainly indicating a garbage key);
+exponent too long for its length to be representable.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_klipsdebug.5.html b/doc/manpage.d/ipsec_klipsdebug.5.html
new file mode 100644
index 000000000..964329256
--- /dev/null
+++ b/doc/manpage.d/ipsec_klipsdebug.5.html
@@ -0,0 +1,229 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_KLIPSDEBUG</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_KLIPSDEBUG</H1>
+Section: File Formats (5)<BR>Updated: 26 Jun 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec_klipsdebug - list KLIPS (kernel IPSEC support) debug features and level
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>klipsdebug</B>
+
+<P>
+
+<B>cat</B>
+
+<B>/proc/net/ipsec_klipsdebug</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>/proc/net/ipsec_klipsdebug</I>
+
+lists flags that control various parts of the debugging output of Klips
+(the kernel portion of FreeS/WAN IPSEC).
+At this point it is a read-only file.
+<P>
+
+A table entry consists of:
+<DL COMPACT>
+<DT>+<DD>
+a KLIPS debug variable
+<DT>+<DD>
+a '=' separator for visual and automated parsing between the variable
+name and its current value
+<DT>+<DD>
+hexadecimal bitmap of variable's flags.
+</DL>
+<P>
+
+The variable names roughly describe the scope of the debugging variable.
+Currently, no flags are documented or individually accessible yet except
+tunnel-xmit.
+
+<P>
+
+The variable names are:
+<DL COMPACT>
+<DT><B>tunnel</B>
+
+<DD>
+tunnelling code
+<DT><B>netlink</B>
+
+<DD>
+userspace communication code (obsolete)
+<DT><B>xform</B>
+
+<DD>
+transform selection and manipulation code
+<DT><B>eroute</B>
+
+<DD>
+eroute table manipulation code
+<DT><B>spi</B>
+
+<DD>
+SA table manipulation code
+<DT><B>radij</B>
+
+<DD>
+radij tree manipulation code
+<DT><B>esp</B>
+
+<DD>
+encryptions transforms code
+<DT><B>ah</B>
+
+<DD>
+authentication transforms code
+<DT><B>rcv</B>
+
+<DD>
+receive code
+<DT><B>ipcomp</B>
+
+<DD>
+ip compression transforms code
+<DT><B>verbose</B>
+
+<DD>
+give even more information, beware this will probably trample the 4k kernel printk buffer giving inaccurate output
+</DL>
+<P>
+
+All KLIPS debug output appears as
+<B>kernel.info</B>
+
+messages to
+<I><A HREF="syslogd.8.html">syslogd</A></I>(8).
+
+Most systems are set up
+to log these messages to
+<I>/var/log/messages</I>.
+
+<P>
+
+<A NAME="lbAE">&nbsp;</A>
+<H2>EXAMPLES</H2>
+
+<P>
+
+<B>debug_tunnel=00000010.</B>
+
+<BR>
+
+<B>debug_netlink=00000000.</B>
+
+<BR>
+
+<B>debug_xform=00000000.</B>
+
+<BR>
+
+<B>debug_eroute=00000000.</B>
+
+<BR>
+
+<B>debug_spi=00000000.</B>
+
+<BR>
+
+<B>debug_radij=00000000.</B>
+
+<BR>
+
+<B>debug_esp=00000000.</B>
+
+<BR>
+
+<B>debug_ah=00000000.</B>
+
+<BR>
+
+<B>debug_rcv=00000000.</B>
+
+<BR>
+
+<B>debug_pfkey=ffffffff.</B>
+
+<P>
+
+means that one
+<B>tunnel</B>
+
+flag has been set (tunnel-xmit),
+full
+<B>pfkey</B>
+
+sockets debugging has been set and everything else is not set.
+<P>
+
+<A NAME="lbAF">&nbsp;</A>
+<H2>FILES</H2>
+
+/proc/net/ipsec_klipsdebug, /usr/local/bin/ipsec
+<A NAME="lbAG">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_manual.8.html">ipsec_manual</A>(8), <A HREF="ipsec_tncfg.8.html">ipsec_tncfg</A>(8), <A HREF="ipsec_eroute.8.html">ipsec_eroute</A>(8),
+<A HREF="ipsec_spi.8.html">ipsec_spi</A>(8), <A HREF="ipsec_spigrp.8.html">ipsec_spigrp</A>(8), <A HREF="ipsec_klipsdebug.5.html">ipsec_klipsdebug</A>(5), <A HREF="ipsec_version.5.html">ipsec_version</A>(5),
+<A HREF="ipsec_pf_key.5.html">ipsec_pf_key</A>(5)
+<A NAME="lbAH">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Richard Guy Briggs.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">EXAMPLES</A><DD>
+<DT><A HREF="#lbAF">FILES</A><DD>
+<DT><A HREF="#lbAG">SEE ALSO</A><DD>
+<DT><A HREF="#lbAH">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_klipsdebug.8.html b/doc/manpage.d/ipsec_klipsdebug.8.html
new file mode 100644
index 000000000..67b1c3a5d
--- /dev/null
+++ b/doc/manpage.d/ipsec_klipsdebug.8.html
@@ -0,0 +1,264 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_KLIPSDEBUG</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_KLIPSDEBUG</H1>
+Section: Maintenance Commands (8)<BR>Updated: 21 Jun 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec klipsdebug - set KLIPS (kernel IPSEC support) debug features and level
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>klipsdebug</B>
+
+<P>
+
+<B>ipsec</B>
+
+<B>klipsdebug</B>
+
+<B>--set</B>
+
+flagname
+<P>
+
+<B>ipsec</B>
+
+<B>klipsdebug</B>
+
+<B>--clear</B>
+
+flagname
+<P>
+
+<B>ipsec</B>
+
+<B>klipsdebug</B>
+
+<B>--all</B>
+
+<P>
+
+<B>ipsec</B>
+
+<B>klipsdebug</B>
+
+<B>--none</B>
+
+<P>
+
+<B>ipsec</B>
+
+<B>klipsdebug</B>
+
+<B>--help</B>
+
+<P>
+
+<B>ipsec</B>
+
+<B>klipsdebug</B>
+
+<B>--version</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Klipsdebug</I>
+
+sets and clears flags that control
+various parts of the debugging output of Klips
+(the kernel portion of FreeS/WAN IPSEC).
+The form with no additional arguments lists the present contents of
+/proc/net/ipsec_klipsdebug.
+The
+<B>--set</B>
+
+form turns the specified flag on,
+while the
+<B>--clear</B>
+
+form turns the specified flag off.
+The 
+<B>--all</B>
+
+form 
+turns all flags on except verbose, while the
+<B>--none</B>
+
+form turns all flags off.
+<P>
+
+The current flag names are:
+<DL COMPACT>
+<DT><B>tunnel</B>
+
+<DD>
+tunnelling code
+<DT><B>tunnel-xmit</B>
+
+<DD>
+tunnelling transmit only code
+<DT><B>pfkey</B>
+
+<DD>
+userspace communication code
+<DT><B>xform</B>
+
+<DD>
+transform selection and manipulation code
+<DT><B>eroute</B>
+
+<DD>
+eroute table manipulation code
+<DT><B>spi</B>
+
+<DD>
+SA table manipulation code
+<DT><B>radij</B>
+
+<DD>
+radij tree manipulation code
+<DT><B>esp</B>
+
+<DD>
+encryptions transforms code
+<DT><B>ah</B>
+
+<DD>
+authentication transforms code
+<B>rcv</B>
+
+receive code
+<DT><B>ipcomp</B>
+
+<DD>
+ip compression transforms code
+<DT><B>verbose</B>
+
+<DD>
+give even more information, BEWARE:
+a)this will print authentication and encryption keys in the logs
+b)this will probably trample the 4k kernel printk buffer giving inaccurate output
+</DL>
+<P>
+
+All Klips debug output appears as
+<B>kernel.info</B>
+
+messages to
+<I><A HREF="syslogd.8.html">syslogd</A></I>(8).
+
+Most systems are set up
+to log these messages to
+<I>/var/log/messages</I>.
+
+Beware that
+<B>klipsdebug</B>
+
+<B>--all</B>
+
+produces a lot of output and the log file will grow quickly.
+<P>
+
+The file format for /proc/net/ipsec_klipsdebug is discussed in
+<A HREF="ipsec_klipsdebug.5.html">ipsec_klipsdebug</A>(5).
+<A NAME="lbAE">&nbsp;</A>
+<H2>EXAMPLES</H2>
+
+<DL COMPACT>
+<DT><B>klipsdebug --all</B>
+
+<DD>
+turns on all KLIPS debugging except verbose.
+<DT><B>klipsdebug --clear tunnel</B>
+
+<DD>
+turns off only the
+<B>tunnel</B>
+
+debugging messages.
+</DL>
+<P>
+
+<A NAME="lbAF">&nbsp;</A>
+<H2>FILES</H2>
+
+/proc/net/ipsec_klipsdebug, /usr/local/bin/ipsec
+<A NAME="lbAG">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_manual.8.html">ipsec_manual</A>(8), <A HREF="ipsec_tncfg.8.html">ipsec_tncfg</A>(8), <A HREF="ipsec_eroute.8.html">ipsec_eroute</A>(8),
+<A HREF="ipsec_spi.8.html">ipsec_spi</A>(8), <A HREF="ipsec_spigrp.8.html">ipsec_spigrp</A>(8), <A HREF="ipsec_klipsdebug.5.html">ipsec_klipsdebug</A>(5)
+<A NAME="lbAH">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Richard Guy Briggs.
+<A NAME="lbAI">&nbsp;</A>
+<H2>BUGS</H2>
+
+It really ought to be possible to set or unset selective combinations
+of flags.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">EXAMPLES</A><DD>
+<DT><A HREF="#lbAF">FILES</A><DD>
+<DT><A HREF="#lbAG">SEE ALSO</A><DD>
+<DT><A HREF="#lbAH">HISTORY</A><DD>
+<DT><A HREF="#lbAI">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_look.8.html b/doc/manpage.d/ipsec_look.8.html
new file mode 100644
index 000000000..ffe07a57c
--- /dev/null
+++ b/doc/manpage.d/ipsec_look.8.html
@@ -0,0 +1,76 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of look</TITLE>
+</HEAD><BODY>
+<H1>look</H1>
+Section: Maintenance Commands (8)<BR>Updated: 25 Apr 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec look - get a quick summary of FreeS/WAN status
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<I>look</I>
+
+is used to get a quick overview of what the status of FreeSWAN is.
+It is equivalent to:
+&nbsp;&nbsp;&nbsp;ipsec eroute
+<P>
+&nbsp;&nbsp;&nbsp;ipsec spigrp
+<P>
+&nbsp;&nbsp;&nbsp;ipsec tncfg
+<P>
+&nbsp;&nbsp;&nbsp;ipsec spi
+<P>
+&nbsp;&nbsp;&nbsp;netstat -rn
+<P>
+<P>
+
+However a bit of processing is done to combine the outputs.
+<A NAME="lbAD">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_tncfg.8.html">ipsec_tncfg</A>(8), <A HREF="ipsec_spi.8.html">ipsec_spi</A>(8), <A HREF="ipsec_spigrp.8.html">ipsec_spigrp</A>(8), <A HREF="ipsec_eroute.5.html">ipsec_eroute</A>(5),
+<A HREF="netstat.8.html">netstat</A>(8).
+<A NAME="lbAE">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Man page written for the Linux FreeS/WAN project &lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Michael Richardson. Original program written by Henry Spencer.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">SEE ALSO</A><DD>
+<DT><A HREF="#lbAE">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_loopbackaddr.3.html b/doc/manpage.d/ipsec_loopbackaddr.3.html
new file mode 100644
index 000000000..92f69d99c
--- /dev/null
+++ b/doc/manpage.d/ipsec_loopbackaddr.3.html
@@ -0,0 +1,166 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ANYADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ANYADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 8 Sept 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec anyaddr - get &quot;any&quot; address
+<BR>
+
+ipsec isanyaddr - test address for equality to &quot;any&quot; address
+<BR>
+
+ipsec unspecaddr - get &quot;unspecified&quot; address
+<BR>
+
+ipsec isunspecaddr - test address for equality to &quot;unspecified&quot; address
+<BR>
+
+ipsec loopbackaddr - get loopback address
+<BR>
+
+ipsec isloopbackaddr - test address for equality to loopback address
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *anyaddr(int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int isanyaddr(const ip_address *src);</B>
+
+<BR>
+
+<B>const char *unspecaddr(int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int isunspecaddr(const ip_address *src);</B>
+
+<BR>
+
+<B>const char *loopbackaddr(int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int isloopbackaddr(const ip_address *src);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions fill in, and test for, special values of the
+<I>ip_address</I>
+
+type.
+<P>
+
+<I>Anyaddr</I>
+
+fills in the destination
+<I>*dst</I>
+
+with the ``any'' address of address family
+<I>af</I>
+
+(normally
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>).
+
+The IPv4 ``any'' address is the one embodied in the old
+<B>INADDR_ANY</B>
+
+macro.
+<P>
+
+<I>Isanyaddr</I>
+
+returns
+<B>1</B>
+
+if the
+<I>src</I>
+
+address equals the ``any'' address,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+Similarly,
+<I>unspecaddr</I>
+
+supplies, and
+<I>isunspecaddr</I>
+
+tests for,
+the ``unspecified'' address,
+which may be the same as the ``any'' address.
+<P>
+
+Similarly,
+<I>loopbackaddr</I>
+
+supplies, and
+<I>islookbackaddr</I>
+
+tests for,
+the loopback address.
+<P>
+
+<I>Anyaddr</I>,
+
+<I>unspecaddr</I>,
+
+and
+<I>loopbackaddr</I>
+
+return
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_addrtot.3.html">ipsec_addrtot</A>(3), <A HREF="ipsec_sameaddr.3.html">ipsec_sameaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in the address-supplying functions are:
+unknown address family.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_lwdnsq.8.html b/doc/manpage.d/ipsec_lwdnsq.8.html
new file mode 100644
index 000000000..1122b188a
--- /dev/null
+++ b/doc/manpage.d/ipsec_lwdnsq.8.html
@@ -0,0 +1,400 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC LWDNSQ</TITLE>
+</HEAD><BODY>
+<H1>IPSEC LWDNSQ</H1>
+Section:  (8)<BR>Updated: <BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+lwdnsq - lookup items in DNS to help pluto (and others)
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<P>
+<PRE>
+<B>ipsec lwdnsq</B> lwdnsq [<B>--prompt</B>] [<B>--serial</B>]
+</PRE>
+
+<P>
+<PRE>
+<B>ipsec lwdnsq</B> lwdnsq [<B>--help</B>]
+</PRE>
+
+<P>
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<P>
+<P>
+
+The <B>ipsec lwdnsq</B> is a helper program that does DNS lookups for other programs. It implements an asynchronous interface on stdin/stdout, with an ASCII driven command language.
+<P>
+<P>
+
+If stdin is a tty or if the <B>--prompt</B> option is given, then it issues a prompt to the user. Otherwise, it is silent, except for results.
+<P>
+<P>
+
+The program will accept multiple queries concurrently, with each result being marked with the ID provided on the output. The IDs are strings.
+<P>
+<P>
+
+If the <B>--serial</B> option is given, then the program will not attempt to execute concurrent queries, but will serialize all input and output.
+<P>
+<A NAME="lbAE">&nbsp;</A>
+<H2>QUERY LANGUAGE</H2>
+
+<P>
+<P>
+
+There are eleven command that the program understands. This is to lookup different types of records in both the forward and reverse maps. Every query includes a queryid, which is returned in the output, on every single line to identify the transaction.
+<P>
+<A NAME="lbAF">&nbsp;</A>
+<H3>KEY queryid FQDN</H3>
+
+<P>
+<P>
+
+This request looks up the KEY resource record for the given <B>FQDN.</B>.
+<P>
+<A NAME="lbAG">&nbsp;</A>
+<H3>KEY4 queryid A.B.C.D</H3>
+
+<P>
+<P>
+
+This request looks up the KEY resource record found in the reverse map for the IP version 4 address <B>A.B.C.D</B>, i.e. it looks up D.C.B.A.in-addr.arpa.
+<P>
+<A NAME="lbAH">&nbsp;</A>
+<H3>KEY6 queryid A:B::C:D</H3>
+
+<P>
+<P>
+
+This request looks up the KEY resource record found in the reverse map for the IPv6 address <B>A:B::C:D</B>, i.e. it looks the 32-nibble long entry in ip6.arpa (and ip6.int).
+<P>
+<A NAME="lbAI">&nbsp;</A>
+<H3>TXT4 queryid A.B.C.D</H3>
+
+<P>
+<P>
+
+This request looks up the TXT resource record found in the reverse map for the IP version 4 address <B>A.B.C.D</B>, i.e. it looks up D.C.B.A.in-addr.arpa.
+<P>
+<A NAME="lbAJ">&nbsp;</A>
+<H3>TXT6 queryid A:B::C:D</H3>
+
+<P>
+<P>
+
+This request looks up the TXT resource record found in the reverse map for the IPv6 address <B>A:B::C:D</B>, i.e. it looks the 32-nibble long entry in ip6.arpa (and ip6.int).
+<P>
+<A NAME="lbAK">&nbsp;</A>
+<H3>KEY queryid FQDN</H3>
+
+<P>
+<P>
+
+This request looks up the IPSECKEY resource record for the given <B>FQDN.</B>. See note about IPSECKEY processing, below.
+<P>
+<A NAME="lbAL">&nbsp;</A>
+<H3>IPSECKEY4 queryid A.B.C.D</H3>
+
+<P>
+<P>
+
+This request looks up the IPSECKEY resource record found in the reverse map for the IP version 4 address <B>A.B.C.D</B>, i.e. it looks up D.C.B.A.in-addr.arpa. See special note about IPSECKEY processing, below.
+<P>
+<A NAME="lbAM">&nbsp;</A>
+<H3>IPSECKEY6 queryid A:B::C:D</H3>
+
+<P>
+<P>
+
+This request looks up the IPSECKEY resource record found in the reverse map for the IPv6 address <B>A:B::C:D</B>, i.e. it looks the 32-nibble long entry in ip6.arpa (and ip6.int). See special note about IPSECKEY processing, below.
+<P>
+<A NAME="lbAN">&nbsp;</A>
+<H3>OE4 queryid A.B.C.D</H3>
+
+<P>
+<P>
+
+This request looks an appropriate record for Opportunistic Encryption for the given IP address. This attempts to look for the delegation record. This may be one of IPSECKEY, KEY, or TXT record. Unless configured otherwise, (see OE4 Directives, below), then a query type of ANY will be used to retrieve all relevant records, and all will be returned.
+<P>
+<A NAME="lbAO">&nbsp;</A>
+<H3>OE6 queryid A:B::C:D</H3>
+
+<P>
+<P>
+
+This request looks an appropriate record for Opportunistic Encryption for the given IPv6 address. This attempts to look for the delegation record. This may be one of IPSECKEY, KEY, or TXT record. Unless configured otherwise, (see OE Directives, below), then a query type of ALL will be used to retrieve all relevant records, and all will be returned. i.e. it looks the 32-nibble long entry in ip6.arpa (and ip6.int).
+<P>
+<A NAME="lbAP">&nbsp;</A>
+<H3>A queryid FQDN</H3>
+
+<P>
+<P>
+
+This request looks up the A (IPv4) resource record for the given <B>FQDN.</B>.
+<P>
+<A NAME="lbAQ">&nbsp;</A>
+<H3>AAAA queryid FQDN</H3>
+
+<P>
+<P>
+
+This request looks up the AAAA (IPv6) resource record for the given <B>FQDN.</B>.
+<P>
+<A NAME="lbAR">&nbsp;</A>
+<H2>REPLIES TO QUERIES</H2>
+
+<P>
+<P>
+
+All replies from the queries are in the following format: 
+<P>
+<PRE>
+
+&lt;ID&gt; &lt;TIME&gt; &lt;TTL&gt; &lt;TYPE&gt; &lt;TYPE-SPECIFIC&gt; \n
+
+</PRE>
+
+<BR>&nbsp;&nbsp;
+<P>
+<DL COMPACT>
+<DT><I>ID</I><DD>
+this is the <B>queryid</B> value that was provided in the query. It is repeated on every line to permit the replies to be properly associated with the query. When the response is not ascribable to particular query (such as for a mis-formed query), then the query ID &quot;0&quot; will be used.
+<P>
+<DT><I>TIME</I><DD>
+this is the current time in seconds since epoch.
+<P>
+<DT><I>TTL</I><DD>
+for answers which have a time to live, this is the current value. The answer is valid for this number of seconds. If there is no useful value here, then the number 0 is used.
+<P>
+<DT><I>TYPE</I><DD>
+This is the type of the record that is being returned. The types are described in the next section. The TYPE specific data that follows is specific to the type.
+<BR>&nbsp;
+<P>
+</DL>
+<P>
+
+The replies are limited to 4096 bytes, a value defined as <B>LWDNSQ_RESULT_LEN_MAX</B>. This is defined in <I>freeswan.h</I>.
+<P>
+<P>
+
+All of the replies which include resource records use the standard presentation format (with no line feeds or carriage returns) in their answer.
+<P>
+<A NAME="lbAS">&nbsp;</A>
+<H3>START</H3>
+
+<P>
+<P>
+
+This reply indicates that a query has been received and has been started. It serves as an anchor point for timing, as well as an acknowledgement.
+<P>
+<A NAME="lbAT">&nbsp;</A>
+<H3>DONE</H3>
+
+<P>
+<P>
+
+This reply indicates that a query is entirely over, and no further information from this query will be sent.
+<P>
+<A NAME="lbAU">&nbsp;</A>
+<H3>RETRY</H3>
+
+<P>
+<P>
+
+This reply indicates that a query is entirely over, but that no data was found. The records may exist, but appropriate servers could not be reached.
+<P>
+<A NAME="lbAV">&nbsp;</A>
+<H3>FATAL</H3>
+
+<P>
+<P>
+
+This reply indicates that a query is entirely over, and that no data of the type requested could be found. There were no timeouts, and all servers were available and confirmed non-existances. There may be NXT records returned prior to this.
+<P>
+<A NAME="lbAW">&nbsp;</A>
+<H3>CNAME</H3>
+
+<P>
+<P>
+
+This is an interim reply, and indicates that a CNAME was found (and followed) while performing the query. The value of the CNAME is present in the type specific section.
+<P>
+<A NAME="lbAX">&nbsp;</A>
+<H3>CNAMEFROM</H3>
+
+<P>
+<P>
+
+This is an interim reply, and indicates that a CNAME was found. The original name that was queries for was not the canonical name, and this reply indicates the name that was actually followed.
+<P>
+<A NAME="lbAY">&nbsp;</A>
+<H3>NAME</H3>
+
+<P>
+<P>
+
+This is an interim reply. The original name that was queries for was not the canonical name. This reply indicates the canonical name.
+<P>
+<A NAME="lbAZ">&nbsp;</A>
+<H3>DNSSEC</H3>
+
+<P>
+<P>
+
+This is an interim reply. It is followed either by &quot;OKAY&quot; or &quot;not present. It indicates if DNSSEC was available on the reply.
+<P>
+<A NAME="lbBA">&nbsp;</A>
+<H3>TXT and AD-TXT</H3>
+
+<P>
+<P>
+
+This is an interim reply. If there are TXT resource records in the reply, then each one is presented using this type. If preceeded by AD-, then this record was signed with DNSSEC.
+<P>
+<A NAME="lbBB">&nbsp;</A>
+<H3>A and AD-A</H3>
+
+<P>
+<P>
+
+This is an interim reply. If there are A resource records in the reply, then each one is presented using this type. If preceeded by AD-, then this record was signed with DNSSEC.
+<P>
+<A NAME="lbBC">&nbsp;</A>
+<H3>AAAA and AD-AAAA</H3>
+
+<P>
+<P>
+
+This is an interim reply. If there are AAAA resource records in the reply, then each one is presented using this type. If preceeded by AD-, then this record was signed with DNSSEC.
+<P>
+<A NAME="lbBD">&nbsp;</A>
+<H3>PTR and AD-PTR</H3>
+
+<P>
+<P>
+
+This is an interim reply. If there are PTR resource records in the reply, then each one is presented using this type. If preceeded by AD-, then this record was signed with DNSSEC.
+<P>
+<A NAME="lbBE">&nbsp;</A>
+<H3>KEY and AD-KEY</H3>
+
+<P>
+<P>
+
+This is an interim reply. If there are KEY resource records in the reply, then each one is presented using this type. If preceeded by AD-, then this record was signed with DNSSEC.
+<P>
+<A NAME="lbBF">&nbsp;</A>
+<H3>IPSECKEY and AD-IPSECKEY</H3>
+
+<P>
+<P>
+
+This is an interim reply. If there are IPSEC resource records in the reply, then each one is presented using this type. If preceeded by AD-, then this record was signed with DNSSEC.
+<P>
+<A NAME="lbBG">&nbsp;</A>
+<H2>SPECIAL IPSECKEY PROCESSING</H2>
+
+<P>
+<P>
+
+At the time of this writing, the IPSECKEY resource record is not entirely specified. In particular no resource record number has been assigned. This program assumes that it is resource record number 45. If the file /etc/ipsec.d/lwdnsq.conf exists, and contains a line like 
+<P>
+<PRE>
+
+ipseckey_rr=<B>number</B>
+
+</PRE>
+
+<BR>&nbsp;then&nbsp;this&nbsp;number&nbsp;will&nbsp;be&nbsp;used&nbsp;instead.&nbsp;The&nbsp;file&nbsp;is&nbsp;read&nbsp;only&nbsp;once&nbsp;at&nbsp;startup.
+<P>
+<A NAME="lbBH">&nbsp;</A>
+<H2>OE DIRECTIVES</H2>
+
+<P>
+<P>
+
+If the file /etc/ipsec.d/lwdnsq.conf exists, and contains a line like 
+<P>
+<PRE>
+
+queryany=false
+
+</PRE>
+
+<BR>&nbsp;then&nbsp;instead&nbsp;of&nbsp;doing&nbsp;an&nbsp;ALL&nbsp;query&nbsp;when&nbsp;looking&nbsp;for&nbsp;OE&nbsp;delegation&nbsp;records,&nbsp;lwdnsq&nbsp;will&nbsp;do&nbsp;a&nbsp;series&nbsp;of&nbsp;queries.&nbsp;It&nbsp;will&nbsp;first&nbsp;look&nbsp;for&nbsp;IPSECKEY,&nbsp;and&nbsp;then&nbsp;TXT&nbsp;record.&nbsp;If&nbsp;it&nbsp;finds&nbsp;neither,&nbsp;it&nbsp;will&nbsp;then&nbsp;look&nbsp;for&nbsp;KEY&nbsp;records&nbsp;of&nbsp;all&nbsp;kinds,&nbsp;although&nbsp;they&nbsp;do&nbsp;not&nbsp;contain&nbsp;delegation&nbsp;information.
+<P>
+<A NAME="lbBI">&nbsp;</A>
+<H2>SPECIAL IPSECKEY PROCESSING</H2>
+
+<P>
+<PRE>
+
+/etc/ipsec.d/lwdnsq.conf
+
+</PRE>
+
+<P>
+<A NAME="lbBJ">&nbsp;</A>
+<H2>AUTHOR</H2>
+
+Michael Richardson &lt;<A HREF="mailto:mcr@sandelman.ottawa.on.ca">mcr@sandelman.ottawa.on.ca</A>&gt;.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">QUERY LANGUAGE</A><DD>
+<DL>
+<DT><A HREF="#lbAF">KEY queryid FQDN</A><DD>
+<DT><A HREF="#lbAG">KEY4 queryid A.B.C.D</A><DD>
+<DT><A HREF="#lbAH">KEY6 queryid A:B::C:D</A><DD>
+<DT><A HREF="#lbAI">TXT4 queryid A.B.C.D</A><DD>
+<DT><A HREF="#lbAJ">TXT6 queryid A:B::C:D</A><DD>
+<DT><A HREF="#lbAK">KEY queryid FQDN</A><DD>
+<DT><A HREF="#lbAL">IPSECKEY4 queryid A.B.C.D</A><DD>
+<DT><A HREF="#lbAM">IPSECKEY6 queryid A:B::C:D</A><DD>
+<DT><A HREF="#lbAN">OE4 queryid A.B.C.D</A><DD>
+<DT><A HREF="#lbAO">OE6 queryid A:B::C:D</A><DD>
+<DT><A HREF="#lbAP">A queryid FQDN</A><DD>
+<DT><A HREF="#lbAQ">AAAA queryid FQDN</A><DD>
+</DL>
+<DT><A HREF="#lbAR">REPLIES TO QUERIES</A><DD>
+<DL>
+<DT><A HREF="#lbAS">START</A><DD>
+<DT><A HREF="#lbAT">DONE</A><DD>
+<DT><A HREF="#lbAU">RETRY</A><DD>
+<DT><A HREF="#lbAV">FATAL</A><DD>
+<DT><A HREF="#lbAW">CNAME</A><DD>
+<DT><A HREF="#lbAX">CNAMEFROM</A><DD>
+<DT><A HREF="#lbAY">NAME</A><DD>
+<DT><A HREF="#lbAZ">DNSSEC</A><DD>
+<DT><A HREF="#lbBA">TXT and AD-TXT</A><DD>
+<DT><A HREF="#lbBB">A and AD-A</A><DD>
+<DT><A HREF="#lbBC">AAAA and AD-AAAA</A><DD>
+<DT><A HREF="#lbBD">PTR and AD-PTR</A><DD>
+<DT><A HREF="#lbBE">KEY and AD-KEY</A><DD>
+<DT><A HREF="#lbBF">IPSECKEY and AD-IPSECKEY</A><DD>
+</DL>
+<DT><A HREF="#lbBG">SPECIAL IPSECKEY PROCESSING</A><DD>
+<DT><A HREF="#lbBH">OE DIRECTIVES</A><DD>
+<DT><A HREF="#lbBI">SPECIAL IPSECKEY PROCESSING</A><DD>
+<DT><A HREF="#lbBJ">AUTHOR</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_mailkey.8.html b/doc/manpage.d/ipsec_mailkey.8.html
new file mode 100644
index 000000000..83a532563
--- /dev/null
+++ b/doc/manpage.d/ipsec_mailkey.8.html
@@ -0,0 +1,97 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_MAILKEY</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_MAILKEY</H1>
+Section: Maintenance Commands (8)<BR>Updated: 21 Feb 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec mailkey - mail DNS records for Opportunistic Encryption
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>mailkey</B>
+
+--me
+<A HREF="mailto:my@address.tld">my@address.tld</A>
+[
+<B>--reverse</B>
+
+1.2.3.4
+] [
+<B>--forward</B>
+
+hostname.domain.tld
+]
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>mailkey</I>
+
+is a meta-program. It generates a script which will attempt to mail the TXT 
+records required to enable Opportunistic Encryption (OE).
+<P>
+
+An e-mail address for the domain's DNS administrator is derived from SOA records. 
+The mail body and destination address are freely editable in the script.
+<P>
+
+If no administrator can be located, the output file will not be executable.
+<P>
+
+<DL COMPACT>
+<DT><B>--me</B>&nbsp;<I><A HREF="mailto:my@address.tld">my@address.tld</A></I><DD>
+set the Reply-To: address of the mail to be sent.
+<DT><B>--forward</B>&nbsp;<I>hostname.domain.tld</I><DD>
+the domain name to be used for initator-only OE.  
+<DT><B>--reverse</B>&nbsp;<I>1.2.3.4</I><DD>
+the IP address to be used for full Opportunistic Encryption.
+</DL>
+<P>
+
+Only one of --forward or --reverse may be specified.
+<A NAME="lbAE">&nbsp;</A>
+<H2>FILES</H2>
+
+<PRE>
+/etc/ipsec.secrets
+</PRE>
+
+<A NAME="lbAF">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec_showhostkey.8.html">ipsec_showhostkey</A>(8), <A HREF="host.8.html">host</A>(8)
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project &lt;<A HREF="http://www.freeswan.org">http://www.freeswan.org</A>&gt; by Sam Sgro.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+May produce indeterminate results when processing non-routable IPs.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">FILES</A><DD>
+<DT><A HREF="#lbAF">SEE ALSO</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_manual.8.html b/doc/manpage.d/ipsec_manual.8.html
new file mode 100644
index 000000000..77134f7d0
--- /dev/null
+++ b/doc/manpage.d/ipsec_manual.8.html
@@ -0,0 +1,414 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_MANUAL</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_MANUAL</H1>
+Section: Maintenance Commands (8)<BR>Updated: 17 July 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec manual - take manually-keyed IPsec connections up and down
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>manual</B>
+
+[
+<B>--show</B>
+
+] [
+<B>--showonly</B>
+
+] [
+<B>--other</B>
+
+]
+<BR>
+
+&nbsp;&nbsp;&nbsp;[
+<B>--iam</B>
+
+address<B>@</B>interface
+
+] [
+<B>--config</B>
+
+configfile
+]
+<BR>
+
+&nbsp;&nbsp;&nbsp;operation connection
+<P>
+<B>ipsec</B>
+
+<B>manual</B>
+
+[
+<I>options</I>
+
+]
+<B>--union</B>
+
+operation part ...
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Manual</I>
+
+manipulates manually-keyed FreeS/WAN IPsec connections,
+setting them up and shutting them down,
+based on the information in the IPsec configuration file.
+In the normal usage,
+<I>connection</I>
+
+is the name of a connection specification in the configuration file;
+<I>operation</I>
+
+is
+<B>--up</B>,
+
+<B>--down</B>,
+
+<B>--route</B>,
+
+or
+<B>--unroute</B>.
+
+<I>Manual</I>
+
+generates setup (<B>--route</B>
+
+or
+<B>--up</B>)
+
+or
+teardown (<B>--down</B>
+
+or
+<B>--unroute</B>)
+
+commands for the connection and feeds them to a shell for execution.
+<P>
+
+The
+<B>--up</B>
+
+operation brings the specified connection up, including establishing a
+suitable route for it if necessary.
+<P>
+
+The
+<B>--route</B>
+
+operation just establishes the route for a connection.
+Unless and until an
+<B>--up</B>
+
+operation is done, packets routed by that route will simply be discarded.
+<P>
+
+The
+<B>--down</B>
+
+operation tears the specified connection down,
+<I>except</I>
+
+that it leaves the route in place.
+Unless and until an
+<B>--unroute</B>
+
+operation is done, packets routed by that route will simply be discarded.
+This permits establishing another connection to the same destination
+without any ``window'' in which packets can pass without encryption.
+<P>
+
+The
+<B>--unroute</B>
+
+operation (and only the
+<B>--unroute</B>
+
+operation) deletes any route established for a connection.
+<P>
+
+In the
+<B>--union</B>
+
+usage, each
+<I>part</I>
+
+is the name of a partial connection specification in the configuration file,
+and the union of all the partial specifications is the
+connection specification used.
+The effect is as if the contents of the partial specifications were
+concatenated together;
+restrictions on duplicate parameters, etc., do apply to the result.
+(The same effect can now be had, more gracefully, using the
+<B>also</B>
+
+parameter in connection descriptions;
+see
+<I><A HREF="ipsec.conf.5.html">ipsec.conf</A></I>(5)
+
+for details.)
+<P>
+
+The
+<B>--show</B>
+
+option turns on the
+<B>-x</B>
+
+option of the shell used to execute the commands,
+so each command is shown as it is executed.
+<P>
+
+The
+<B>--showonly</B>
+
+option causes
+<I>manual</I>
+
+to show the commands it would run, on standard output,
+and not run them.
+<P>
+
+The
+<B>--other</B>
+
+option causes
+<I>manual</I>
+
+to pretend it is the other end of the connection.
+This is probably not useful except in combination with
+<B>--showonly</B>.
+
+<P>
+
+The
+<B>--iam</B>
+
+option causes
+<I>manual</I>
+
+to believe it is running on the host with the specified IP
+<I>address</I>,
+
+and that it should use the specified
+<I>interface</I>
+
+(normally it determines all this automatically,
+based on what IPsec interfaces are up and how they are configured).
+<P>
+
+The
+<B>--config</B>
+
+option specifies a non-standard location for the FreeS/WAN IPsec
+configuration file (default
+<I>/etc/ipsec.conf</I>).
+
+<P>
+
+See
+<I><A HREF="ipsec.conf.5.html">ipsec.conf</A></I>(5)
+
+for details of the configuration file.
+Apart from the basic parameters which specify the endpoints and routing
+of a connection (<B>left</B>
+and
+<B>right</B>,
+
+plus possibly
+<B>leftsubnet</B>,
+
+<B>leftnexthop</B>,
+
+<B>leftfirewall</B>,
+
+their
+<B>right</B>
+
+equivalents,
+and perhaps
+<B>type</B>),
+
+a non-<B>passthrough</B>
+<I>manual</I>
+
+connection needs an
+<B>spi</B>
+
+or
+<B>spibase</B>
+
+parameter and some parameters specifying encryption, authentication, or
+both, most simply
+<B>esp</B>,
+
+<B>espenckey</B>,
+
+and
+<B>espauthkey</B>.
+
+Moderately-secure keys can be obtained from
+<I><A HREF="ipsec_ranbits.8.html">ipsec_ranbits</A></I>(8).
+
+For production use of manually-keyed connections,
+it is strongly recommended that the keys be kept in a separate file
+(with permissions
+<B>rw-------</B>)
+
+using the
+<B>include</B>
+
+and
+<B>also</B>
+
+facilities of the configuration file (see
+<I><A HREF="ipsec.conf.5.html">ipsec.conf</A></I>(5)).
+
+<P>
+
+If an
+<B>spi</B>
+
+parameter is given,
+<I>manual</I>
+
+uses that value as the SPI number for all the SAs
+(which are in separate number spaces anyway).
+If an
+<B>spibase</B>
+
+parameter is given instead,
+<I>manual</I>
+
+assigns SPI values by altering the bottom digit
+of that value;
+SAs going from left to right get even digits starting at 0,
+SAs going from right to left get odd digits starting at 1.
+Either way, it is suggested that manually-keyed connections use
+three-digit SPIs with the first digit non-zero,
+i.e. in the range
+<B>0x100</B>
+
+through
+<B>0xfff</B>;
+
+FreeS/WAN reserves those for manual keying and will not
+attempt to use them for automatic keying (unless requested to,
+presumably by a non-FreeS/WAN other end).
+<A NAME="lbAE">&nbsp;</A>
+<H2>FILES</H2>
+
+
+
+/etc/ipsec.conf<TT>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TT>default IPsec configuration file<BR>
+<BR>
+
+/var/run/ipsec.info<TT>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TT><B>%defaultroute</B> information<BR>
+<A NAME="lbAF">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec.conf.5.html">ipsec.conf</A>(5), <A HREF="ipsec_spi.8.html">ipsec_spi</A>(8), <A HREF="ipsec_eroute.8.html">ipsec_eroute</A>(8), <A HREF="ipsec_spigrp.8.html">ipsec_spigrp</A>(8),
+<A HREF="route.8.html">route</A>(8)
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+It's not nearly as generous about the syntax of subnets,
+addresses, etc. as the usual FreeS/WAN user interfaces.
+Four-component dotted-decimal must be used for all addresses.
+It
+<I>is</I>
+
+smart enough to translate bit-count netmasks to dotted-decimal form.
+<P>
+
+If the connection specification for a connection is changed between an
+<B>--up</B>
+
+and the ensuing
+<B>--down</B>,
+
+chaos may ensue.
+<P>
+
+The
+<B>--up</B>
+
+operation is not smart enough to notice whether the connection is already up.
+<P>
+
+<I>Manual</I>
+
+is not smart enough to reject insecure combinations of algorithms,
+e.g. encryption with no authentication at all.
+<P>
+
+Any non-IPsec route to the other end which is replaced by the
+<B>--up</B>
+
+or
+<B>--route</B>
+
+operation will not be re-established by
+<B>--unroute</B>.
+
+Whether this is a feature or a bug depends on your viewpoint.
+<P>
+
+The optional parameters which
+override the automatic
+<B>spibase</B>-based
+
+SPI assignment are a messy area of the code and bugs are likely.
+<P>
+
+``Road warrior'' handling,
+and other special forms of setup which
+require negotiation between the two security gateways,
+inherently cannot be done with
+<I>manual</I>.
+
+<P>
+
+<I>Manual</I>
+
+generally lags behind
+<I>auto</I>
+
+in support of various features,
+even when implementation <I>would</I> be possible.
+For example, currently it does not do IPComp content compression.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">FILES</A><DD>
+<DT><A HREF="#lbAF">SEE ALSO</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_maskof.3.html b/doc/manpage.d/ipsec_maskof.3.html
new file mode 100644
index 000000000..ea0f83f82
--- /dev/null
+++ b/doc/manpage.d/ipsec_maskof.3.html
@@ -0,0 +1,238 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_INITSUBNET</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_INITSUBNET</H1>
+Section: C Library Functions (3)<BR>Updated: 12 March 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec initsubnet - initialize an ip_subnet
+<BR>
+
+ipsec addrtosubnet - initialize a singleton ip_subnet
+<BR>
+
+ipsec subnettypeof - get address type of an ip_subnet
+<BR>
+
+ipsec masktocount - convert subnet mask to bit count
+<BR>
+
+ipsec networkof - get base address of an ip_subnet
+<BR>
+
+ipsec maskof - get subnet mask of an ip_subnet
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *initsubnet(const ip_address *addr,</B>
+
+<BR>
+&nbsp;
+<B>int maskbits, int clash, ip_subnet *dst);</B>
+
+<BR>
+
+<B>const char *addrtosubnet(const ip_address *addr,</B>
+
+<BR>
+&nbsp;
+<B>ip_subnet *dst);</B>
+
+<P>
+<B>int subnettypeof(const ip_subnet *src);</B>
+
+<BR>
+
+<B>int masktocount(const ip_address *src);</B>
+
+<BR>
+
+<B>void networkof(const ip_subnet *src, ip_address *dst);</B>
+
+<BR>
+
+<B>void maskof(const ip_subnet *src, ip_address *dst);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+library uses an internal type
+<I>ip_subnet</I>
+
+to contain a description of an IP subnet
+(base address plus mask).
+These functions provide basic tools for creating and examining this type.
+<P>
+
+<I>Initsubnet</I>
+
+initializes a variable
+<I>*dst</I>
+
+of type
+<I>ip_subnet</I>
+
+from a base address and
+a count of mask bits.
+The
+<I>clash</I>
+
+parameter specifies what to do if the base address includes
+<B>1</B>
+
+bits outside the prefix specified by the mask
+(that is, in the ``host number'' part of the address):
+<DL COMPACT><DT><DD>
+<DL COMPACT>
+<DT>'0'<DD>
+zero out host-number bits
+<DT>'x'<DD>
+non-zero host-number bits are an error
+</DL>
+</DL>
+
+<P>
+
+<I>Initsubnet</I>
+
+returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<P>
+
+<I>Addrtosubnet</I>
+
+initializes an
+<I>ip_subnet</I>
+
+variable
+<I>*dst</I>
+
+to a ``singleton subnet'' containing the single address
+<I>*addr</I>.
+
+It returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure.
+<P>
+
+<I>Subnettypeof</I>
+
+returns the address type of a subnet,
+normally
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>.
+
+(The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file arranges to include the necessary headers for these
+names to be known.)
+<P>
+
+<I>Masktocount</I>
+
+converts a subnet mask, expressed as an address, to a bit count
+suitable for use with
+<I>initsubnet</I>.
+
+It returns
+<B>-1</B>
+
+for error; see DIAGNOSTICS.
+<P>
+
+<I>Networkof</I>
+
+fills in
+<I>*dst</I>
+
+with the base address of subnet
+<I>src</I>.
+
+<P>
+
+<I>Maskof</I>
+
+fills in
+<I>*dst</I>
+
+with the subnet mask of subnet
+<I>src</I>,
+
+expressed as an address.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_ttosubnet.3.html">ipsec_ttosubnet</A>(3), <A HREF="ipsec_rangetosubnet.3.html">ipsec_rangetosubnet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>initsubnet</I>
+
+are:
+unknown address family;
+unknown
+<I>clash</I>
+
+value;
+impossible mask bit count;
+non-zero host-number bits and
+<I>clash</I>
+
+is
+<B>'x'</B>.
+
+Fatal errors in
+<I>addrtosubnet</I>
+
+are:
+unknown address family.
+Fatal errors in
+<I>masktocount</I>
+
+are:
+unknown address family;
+mask bits not contiguous.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_masktobits.3.html b/doc/manpage.d/ipsec_masktobits.3.html
new file mode 100644
index 000000000..6eccdd8d5
--- /dev/null
+++ b/doc/manpage.d/ipsec_masktobits.3.html
@@ -0,0 +1,122 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_GOODMASK</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_GOODMASK</H1>
+Section: C Library Functions (3)<BR>Updated: 11 June 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec goodmask - is this Internet subnet mask a valid one?
+<BR>
+
+ipsec masktobits - convert Internet subnet mask to bit count
+<BR>
+
+ipsec bitstomask - convert bit count to Internet subnet mask
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>int goodmask(struct in_addr mask);</B>
+
+<BR>
+
+<B>int masktobits(struct in_addr mask);</B>
+
+<BR>
+
+<B>struct in_addr bitstomask(int n);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions are obsolete;
+see
+<I><A HREF="ipsec_masktocount.3.html">ipsec_masktocount</A></I>(3)
+
+for a partial replacement.
+<P>
+
+<I>Goodmask</I>
+
+reports whether the subnet
+<I>mask</I>
+
+is a valid one,
+i.e. consists of a (possibly empty) sequence of
+<B>1</B>s
+
+followed by a (possibly empty) sequence of
+<B>0</B>s.
+
+<I>Masktobits</I>
+
+takes a (valid) subnet mask and returns the number of
+<B>1</B>
+
+bits in it.
+<I>Bitstomask</I>
+
+reverses this,
+returning the subnet mask corresponding to bit count
+<I>n</I>.
+
+<P>
+
+All masks are in network byte order.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_atosubnet.3.html">ipsec_atosubnet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+<I>Masktobits</I>
+
+returns
+<B>-1</B>
+
+for an invalid mask.
+<I>Bitstomask</I>
+
+returns an all-zeros mask for a negative or out-of-range
+<I>n</I>.
+
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+The error-reporting convention of
+<I>bitstomask</I>
+
+is less than ideal;
+zero is sometimes a legitimate mask.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_masktocount.3.html b/doc/manpage.d/ipsec_masktocount.3.html
new file mode 100644
index 000000000..ea0f83f82
--- /dev/null
+++ b/doc/manpage.d/ipsec_masktocount.3.html
@@ -0,0 +1,238 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_INITSUBNET</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_INITSUBNET</H1>
+Section: C Library Functions (3)<BR>Updated: 12 March 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec initsubnet - initialize an ip_subnet
+<BR>
+
+ipsec addrtosubnet - initialize a singleton ip_subnet
+<BR>
+
+ipsec subnettypeof - get address type of an ip_subnet
+<BR>
+
+ipsec masktocount - convert subnet mask to bit count
+<BR>
+
+ipsec networkof - get base address of an ip_subnet
+<BR>
+
+ipsec maskof - get subnet mask of an ip_subnet
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *initsubnet(const ip_address *addr,</B>
+
+<BR>
+&nbsp;
+<B>int maskbits, int clash, ip_subnet *dst);</B>
+
+<BR>
+
+<B>const char *addrtosubnet(const ip_address *addr,</B>
+
+<BR>
+&nbsp;
+<B>ip_subnet *dst);</B>
+
+<P>
+<B>int subnettypeof(const ip_subnet *src);</B>
+
+<BR>
+
+<B>int masktocount(const ip_address *src);</B>
+
+<BR>
+
+<B>void networkof(const ip_subnet *src, ip_address *dst);</B>
+
+<BR>
+
+<B>void maskof(const ip_subnet *src, ip_address *dst);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+library uses an internal type
+<I>ip_subnet</I>
+
+to contain a description of an IP subnet
+(base address plus mask).
+These functions provide basic tools for creating and examining this type.
+<P>
+
+<I>Initsubnet</I>
+
+initializes a variable
+<I>*dst</I>
+
+of type
+<I>ip_subnet</I>
+
+from a base address and
+a count of mask bits.
+The
+<I>clash</I>
+
+parameter specifies what to do if the base address includes
+<B>1</B>
+
+bits outside the prefix specified by the mask
+(that is, in the ``host number'' part of the address):
+<DL COMPACT><DT><DD>
+<DL COMPACT>
+<DT>'0'<DD>
+zero out host-number bits
+<DT>'x'<DD>
+non-zero host-number bits are an error
+</DL>
+</DL>
+
+<P>
+
+<I>Initsubnet</I>
+
+returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<P>
+
+<I>Addrtosubnet</I>
+
+initializes an
+<I>ip_subnet</I>
+
+variable
+<I>*dst</I>
+
+to a ``singleton subnet'' containing the single address
+<I>*addr</I>.
+
+It returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure.
+<P>
+
+<I>Subnettypeof</I>
+
+returns the address type of a subnet,
+normally
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>.
+
+(The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file arranges to include the necessary headers for these
+names to be known.)
+<P>
+
+<I>Masktocount</I>
+
+converts a subnet mask, expressed as an address, to a bit count
+suitable for use with
+<I>initsubnet</I>.
+
+It returns
+<B>-1</B>
+
+for error; see DIAGNOSTICS.
+<P>
+
+<I>Networkof</I>
+
+fills in
+<I>*dst</I>
+
+with the base address of subnet
+<I>src</I>.
+
+<P>
+
+<I>Maskof</I>
+
+fills in
+<I>*dst</I>
+
+with the subnet mask of subnet
+<I>src</I>,
+
+expressed as an address.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_ttosubnet.3.html">ipsec_ttosubnet</A>(3), <A HREF="ipsec_rangetosubnet.3.html">ipsec_rangetosubnet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>initsubnet</I>
+
+are:
+unknown address family;
+unknown
+<I>clash</I>
+
+value;
+impossible mask bit count;
+non-zero host-number bits and
+<I>clash</I>
+
+is
+<B>'x'</B>.
+
+Fatal errors in
+<I>addrtosubnet</I>
+
+are:
+unknown address family.
+Fatal errors in
+<I>masktocount</I>
+
+are:
+unknown address family;
+mask bits not contiguous.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_networkof.3.html b/doc/manpage.d/ipsec_networkof.3.html
new file mode 100644
index 000000000..ea0f83f82
--- /dev/null
+++ b/doc/manpage.d/ipsec_networkof.3.html
@@ -0,0 +1,238 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_INITSUBNET</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_INITSUBNET</H1>
+Section: C Library Functions (3)<BR>Updated: 12 March 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec initsubnet - initialize an ip_subnet
+<BR>
+
+ipsec addrtosubnet - initialize a singleton ip_subnet
+<BR>
+
+ipsec subnettypeof - get address type of an ip_subnet
+<BR>
+
+ipsec masktocount - convert subnet mask to bit count
+<BR>
+
+ipsec networkof - get base address of an ip_subnet
+<BR>
+
+ipsec maskof - get subnet mask of an ip_subnet
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *initsubnet(const ip_address *addr,</B>
+
+<BR>
+&nbsp;
+<B>int maskbits, int clash, ip_subnet *dst);</B>
+
+<BR>
+
+<B>const char *addrtosubnet(const ip_address *addr,</B>
+
+<BR>
+&nbsp;
+<B>ip_subnet *dst);</B>
+
+<P>
+<B>int subnettypeof(const ip_subnet *src);</B>
+
+<BR>
+
+<B>int masktocount(const ip_address *src);</B>
+
+<BR>
+
+<B>void networkof(const ip_subnet *src, ip_address *dst);</B>
+
+<BR>
+
+<B>void maskof(const ip_subnet *src, ip_address *dst);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+library uses an internal type
+<I>ip_subnet</I>
+
+to contain a description of an IP subnet
+(base address plus mask).
+These functions provide basic tools for creating and examining this type.
+<P>
+
+<I>Initsubnet</I>
+
+initializes a variable
+<I>*dst</I>
+
+of type
+<I>ip_subnet</I>
+
+from a base address and
+a count of mask bits.
+The
+<I>clash</I>
+
+parameter specifies what to do if the base address includes
+<B>1</B>
+
+bits outside the prefix specified by the mask
+(that is, in the ``host number'' part of the address):
+<DL COMPACT><DT><DD>
+<DL COMPACT>
+<DT>'0'<DD>
+zero out host-number bits
+<DT>'x'<DD>
+non-zero host-number bits are an error
+</DL>
+</DL>
+
+<P>
+
+<I>Initsubnet</I>
+
+returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<P>
+
+<I>Addrtosubnet</I>
+
+initializes an
+<I>ip_subnet</I>
+
+variable
+<I>*dst</I>
+
+to a ``singleton subnet'' containing the single address
+<I>*addr</I>.
+
+It returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure.
+<P>
+
+<I>Subnettypeof</I>
+
+returns the address type of a subnet,
+normally
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>.
+
+(The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file arranges to include the necessary headers for these
+names to be known.)
+<P>
+
+<I>Masktocount</I>
+
+converts a subnet mask, expressed as an address, to a bit count
+suitable for use with
+<I>initsubnet</I>.
+
+It returns
+<B>-1</B>
+
+for error; see DIAGNOSTICS.
+<P>
+
+<I>Networkof</I>
+
+fills in
+<I>*dst</I>
+
+with the base address of subnet
+<I>src</I>.
+
+<P>
+
+<I>Maskof</I>
+
+fills in
+<I>*dst</I>
+
+with the subnet mask of subnet
+<I>src</I>,
+
+expressed as an address.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_ttosubnet.3.html">ipsec_ttosubnet</A>(3), <A HREF="ipsec_rangetosubnet.3.html">ipsec_rangetosubnet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>initsubnet</I>
+
+are:
+unknown address family;
+unknown
+<I>clash</I>
+
+value;
+impossible mask bit count;
+non-zero host-number bits and
+<I>clash</I>
+
+is
+<B>'x'</B>.
+
+Fatal errors in
+<I>addrtosubnet</I>
+
+are:
+unknown address family.
+Fatal errors in
+<I>masktocount</I>
+
+are:
+unknown address family;
+mask bits not contiguous.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_newhostkey.8.html b/doc/manpage.d/ipsec_newhostkey.8.html
new file mode 100644
index 000000000..e6cf302bf
--- /dev/null
+++ b/doc/manpage.d/ipsec_newhostkey.8.html
@@ -0,0 +1,196 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_NEWHOSTKEY</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_NEWHOSTKEY</H1>
+Section: Maintenance Commands (8)<BR>Updated: 4 March 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec newhostkey - generate a new host authentication key
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>newhostkey</B>
+
+<B>--output</B>
+
+filename
+[
+<B>--quiet</B>
+
+]
+<B>\</B>
+
+<BR>
+
+
+[
+<B>--bits</B>
+
+n
+]
+[
+<B>--hostname</B>
+
+host
+]
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Newhostkey</I>
+
+outputs (into
+<I>filename</I>,
+
+which can be `<B>-</B>' for standard output)
+an RSA private key suitable for this host,
+in
+<I>/etc/ipsec.secrets</I>
+
+format
+(see
+<I><A HREF="ipsec.secrets.5.html">ipsec.secrets</A></I>(5)).
+
+Normally,
+<I>newhostkey</I>
+
+invokes
+<I>rsasigkey</I>
+
+(see
+<I><A HREF="ipsec_rsasigkey.8.html">ipsec_rsasigkey</A></I>(8))
+
+with the
+<B>--verbose</B>
+
+option, so a narrative of what is being done appears on standard error.
+<P>
+
+The
+<B>--output</B>
+
+specifier, although it is syntactically an option and can appear at
+any point among the options (it doesn't have to be first),
+is not optional.
+The specified
+<I>filename</I>
+
+is created under umask
+<B>077</B>
+
+if nonexistent;
+if it already exists and is non-empty,
+a warning message about that is sent to standard error,
+and the output is appended to the file.
+<P>
+
+The
+<B>--quiet</B>
+
+option suppresses both the
+<I>rsasigkey</I>
+
+narrative and the existing-file warning message.
+<P>
+
+The
+<B>--bits</B>
+
+option specifies the number of bits in the key;
+the current default is 2192 and we do not recommend use of anything
+shorter unless unusual constraints demand it.
+<P>
+
+The
+<B>--hostname</B>
+
+option is passed through to
+<I>rsasigkey</I>
+
+to tell it what host name to label the output with
+(via its
+<B>--hostname</B>
+
+option).
+<P>
+
+The output format is that of
+<I>rsasigkey</I>,
+
+with bracketing added to complete the
+<I>ipsec.secrets</I>
+
+format.
+In the usual case, where
+<I>ipsec.secrets</I>
+
+contains only the host's own private key,
+the output of
+<I>newhostkey</I>
+
+is sufficient as a complete
+<I>ipsec.secrets</I>
+
+file.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.secrets.5.html">ipsec.secrets</A>(5), <A HREF="ipsec_rsasigkey.8.html">ipsec_rsasigkey</A>(8)
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org">http://www.freeswan.org</A>&gt;
+by Henry Spencer.
+<A NAME="lbAG">&nbsp;</A>
+<H2>BUGS</H2>
+
+As with
+<I>rsasigkey</I>,
+
+the run time is difficult to predict,
+since depletion of the system's randomness pool can cause
+arbitrarily long waits for random bits,
+and the prime-number searches can also take unpredictable
+(and potentially large) amounts of CPU time.
+See
+<I><A HREF="ipsec_rsasigkey.8.html">ipsec_rsasigkey</A></I>(8)
+
+for some typical performance numbers.
+<P>
+
+A higher-level tool which could handle the clerical details
+of changing to a new key would be helpful.
+<P>
+
+The requirement for
+<B>--output</B>
+
+is a blemish,
+but private keys are extremely sensitive information
+and unusual precautions seem justified.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+<DT><A HREF="#lbAG">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_optionsfrom.3.html b/doc/manpage.d/ipsec_optionsfrom.3.html
new file mode 100644
index 000000000..05d045e4d
--- /dev/null
+++ b/doc/manpage.d/ipsec_optionsfrom.3.html
@@ -0,0 +1,275 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_OPTIONSFROM</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_OPTIONSFROM</H1>
+Section: C Library Functions (3)<BR>Updated: 16 Oct 1998<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec optionsfrom - read additional ``command-line'' options from file
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *optionsfrom(char *filename, int *argcp,</B>
+
+<BR>
+&nbsp;
+<B>char ***argvp, int optind, FILE *errsto);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Optionsfrom</I>
+
+is called from within a
+<I><A HREF="getopt_long.3.html">getopt_long</A></I>(3)
+
+scan,
+as the result of the appearance of an option (preferably
+<B>--optionsfrom</B>)
+
+to insert additional ``command-line'' arguments
+into the scan immediately after
+the option.
+Typically this would be done to pick up options which are
+security-sensitive and should not be visible to
+<I><A HREF="ps.1.html">ps</A></I>(1)
+
+and similar commands,
+and hence cannot be supplied as part
+of the actual command line or the environment.
+<P>
+
+<I>Optionsfrom</I>
+
+reads the additional arguments from the specified
+<I>filename</I>,
+
+allocates a new argument vector to hold pointers to the existing
+arguments plus the new ones,
+and amends
+<I>argc</I>
+
+and
+<I>argv</I>
+
+(via the pointers
+<I>argcp</I>
+
+and
+<I>argvp</I>,
+
+which must point to the
+<I>argc</I>
+
+and
+<I>argv</I>
+
+being supplied to
+<I><A HREF="getopt_long.3.html">getopt_long</A></I>(3))
+
+accordingly.
+<I>Optind</I>
+
+must be the index, in the original argument vector,
+of the next argument.
+<P>
+
+If
+<I>errsto</I>
+
+is NULL,
+<I>optionsfrom</I>
+
+returns NULL for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+If
+<I>errsto</I>
+
+is non-NULL and an error occurs,
+<I>optionsfrom</I>
+
+prints a suitable complaint onto the
+<I>errsto</I>
+
+descriptor and invokes
+<I>exit</I>
+
+with an exit status of 2;
+this is a convenience for cases where more sophisticated
+responses are not required.
+<P>
+
+The text of existing arguments is not disturbed by
+<I>optionsfrom</I>,
+
+so pointers to them and into them remain valid.
+<P>
+
+The file of additional arguments is an ASCII text file.
+Lines consisting solely of white space,
+and lines beginning with
+<B>#</B>,
+
+are comments and are ignored.
+Otherwise, a line which does not begin with
+<B>-</B>
+
+is taken to be a single argument;
+if it both begins and ends with double-quote (&quot;),
+those quotes are stripped off (note, no other processing is done within
+the line!).
+A line beginning with
+<B>-</B>
+
+is considered to contain multiple arguments separated by white space.
+<P>
+
+Because
+<I>optionsfrom</I>
+
+reads its entire file before the
+<I><A HREF="getopt_long.3.html">getopt_long</A></I>(3)
+
+scan is resumed, an
+<I>optionsfrom</I>
+
+file can contain another
+<B>--optionsfrom</B>
+
+option.
+Obviously, infinite loops are possible here.
+If
+<I>errsto</I>
+
+is non-NULL,
+<I>optionsfrom</I>
+
+considers it an error to be called more than 100 times.
+If
+<I>errsto</I>
+
+is NULL,
+loop detection is up to the caller
+(and the internal loop counter is zeroed out).
+<A NAME="lbAE">&nbsp;</A>
+<H2>EXAMPLE</H2>
+
+A reasonable way to invoke
+<I>optionsfrom</I>
+
+would be like so:
+<P>
+
+<PRE>
+<B>#include &lt;<A HREF="file:/usr/include/getopt.h">getopt.h</A>&gt;
+
+struct option opts[] = {
+        /* ... */
+        &quot;optionsfrom&quot;,  1,      NULL,   '+',
+        /* ... */
+};
+
+int
+main(argc, argv)
+int argc;
+char *argv[];
+{
+        int opt;
+        extern char *optarg;
+        extern int optind;
+
+        while ((opt = getopt_long(argc, argv, &quot;&quot;, opts, NULL)) != EOF)
+                switch (opt) {
+                /* ... */
+                case '+':       /* optionsfrom */
+                        optionsfrom(optarg, &amp;argc, &amp;argv, optind, stderr);
+                        /* does not return on error */
+                        break;
+                /* ... */
+                }
+        /* ... */
+</B></PRE>
+
+<A NAME="lbAF">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="getopt_long.3.html">getopt_long</A>(3)
+<A NAME="lbAG">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Errors in
+<I>optionsfrom</I>
+
+are:
+unable to open file;
+attempt to allocate temporary storage for argument or
+argument vector failed;
+read error in file;
+line too long.
+<A NAME="lbAH">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAI">&nbsp;</A>
+<H2>BUGS</H2>
+
+The double-quote convention is rather simplistic.
+<P>
+
+Line length is currently limited to 1023 bytes,
+and there is no continuation convention.
+<P>
+
+The restriction of error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The error-reporting convention lends itself
+to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+<P>
+
+There is a certain element of unwarranted chumminess with
+the insides of
+<I><A HREF="getopt_long.3.html">getopt_long</A></I>(3)
+
+here.
+No non-public interfaces are actually used, but
+<I>optionsfrom</I>
+
+does rely on
+<I><A HREF="getopt_long.3.html">getopt_long</A></I>(3)
+
+being well-behaved in certain ways that are not actually
+promised by the specs.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">EXAMPLE</A><DD>
+<DT><A HREF="#lbAF">SEE ALSO</A><DD>
+<DT><A HREF="#lbAG">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAH">HISTORY</A><DD>
+<DT><A HREF="#lbAI">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_pf_key.5.html b/doc/manpage.d/ipsec_pf_key.5.html
new file mode 100644
index 000000000..420c12900
--- /dev/null
+++ b/doc/manpage.d/ipsec_pf_key.5.html
@@ -0,0 +1,176 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_PF_KEY</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_PF_KEY</H1>
+Section: File Formats (5)<BR>Updated: 29 Jun 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec_pf_key - lists PF_KEY sockets registered with KLIPS
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>cat</B>
+
+<B>/proc/net/pf_key</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>/proc/net/pf_key</I>
+
+is a read-only file which lists the presently open PF_KEY sockets on the
+local system and their parameters.
+<P>
+
+Each line lists one PF_KEY socket.
+A table entry consists of:
+<DL COMPACT>
+<DT>+<DD>
+sock pointer (sock)
+<DT>+<DD>
+PID of the socket owner (pid)
+<DT>+<DD>
+flag to indicate if the socket is dead (d)
+<DT>+<DD>
+socket wait queue (sleep)
+<DT>+<DD>
+socket pointer (socket)
+<DT>+<DD>
+next socket in chain (next)
+<DT>+<DD>
+previous socket in chain (prev)
+<DT>+<DD>
+last socket error (e)
+<DT>+<DD>
+pointer to destruct routine (destruct)
+<DT>+<DD>
+is this a reused socket (r)
+<DT>+<DD>
+has this socket been zapped (z)
+<DT>+<DD>
+socket family to which this socket belongs (fa)
+<DT>+<DD>
+local port number (n)
+<DT>+<DD>
+protocol version number (p)
+<DT>+<DD>
+Receive queue bytes committed (r)
+<DT>+<DD>
+Transmit queue bytes committed (w)
+<DT>+<DD>
+option memory allocations (o)
+<DT>+<DD>
+size of send buffer in bytes (sndbf)
+<DT>+<DD>
+timestamp in seconds (stamp)
+<DT>+<DD>
+socket flags (Flags)
+<DT>+<DD>
+socket type (Type)
+<DT>+<DD>
+connection state (St)
+<B>.SH</B>EXAMPLES
+
+<DT>
+<DD>
+<DT><B>c3b8c140 3553 0 c0599818 c05997fc        0        0 0        0 1 0 15 0 2 0 0 0 65535 0.103232 00000000 00000003 01</B>
+
+<DD>
+</DL>
+<P>
+
+shows that there is one pf_key socket set up that starts at
+<B>c3b8c140</B>,
+
+whose owning process has PID
+<B>3553</B>,
+
+the socket is not dead, its wait queue is at
+<B>c0599818</B>,
+
+whose owning socket is at
+<B>c05997fc</B>,
+
+with no other sockets in the chain, no errors, no destructor, it is a
+reused socket which has not been zapped, from protocol family
+<B>15</B>
+
+(PF_KEY), local port number
+<B>0</B>,
+
+protocol socket version
+<B>2</B>,
+
+no memory allocated to transmit, receive or option queues, a send buffer
+of almost
+<B>64kB</B>,
+
+a timestamp of
+<B>0.103232</B>,
+
+no flags set, type
+<B>3</B>,
+
+in state
+<B>1</B>.
+
+<A NAME="lbAE">&nbsp;</A>
+<H2>FILES</H2>
+
+/proc/net/pf_key
+<A NAME="lbAF">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_manual.8.html">ipsec_manual</A>(8), <A HREF="ipsec_eroute.5.html">ipsec_eroute</A>(5), <A HREF="ipsec_spi.5.html">ipsec_spi</A>(5),
+<A HREF="ipsec_spigrp.5.html">ipsec_spigrp</A>(5), <A HREF="ipsec_klipsdebug.5.html">ipsec_klipsdebug</A>(5), <A HREF="ipsec_tncfg.8.html">ipsec_tncfg</A>(8), <A HREF="ipsec_version.5.html">ipsec_version</A>(5)
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Richard Guy Briggs.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">FILES</A><DD>
+<DT><A HREF="#lbAF">SEE ALSO</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_pf_key.8.html b/doc/manpage.d/ipsec_pf_key.8.html
new file mode 100644
index 000000000..e40cfb15b
--- /dev/null
+++ b/doc/manpage.d/ipsec_pf_key.8.html
@@ -0,0 +1,122 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_PF_KEY</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_PF_KEY</H1>
+Section: User Commands  (1)<BR>Updated: 17 Oct 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+pf_key - shows pfkey messages emitted by the kernel
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>pf_key</B>
+
+<B>--ah</B>
+
+<B>--esp</B>
+
+<B>--ipip</B>
+
+<B>--ipcomp</B>
+
+<B>--daemon </B>
+
+<I>file</I>
+
+<B>hmac-md5-96</B>|<B>hmac-sha1-96</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<B>pf_key</B>
+
+is a program to open a PF_KEY socket and print all messages that are received
+from it. With no options, it will register itself to receive key requests for
+AH, ESP, IPIP and IPCOMP security associations. If given more specific
+options, then it will listen only to those protocols which are listed.
+<P>
+
+If the messages are recognized, the messages will be decoded.
+<P>
+
+If the option 
+<B>--daemon</B>
+
+is provided, then after doing the registrations, the program will fork
+into the background. The provided file will be opened and the process ID of
+the background process will be written to it. This option is present to
+present race conditions in regression testing.
+<A NAME="lbAE">&nbsp;</A>
+<H2>EXAMPLES</H2>
+
+<DL COMPACT>
+<DT>
+<DD>
+</DL>
+<A NAME="lbAF">&nbsp;</A>
+<H2>FILES</H2>
+
+/proc/net/pf_key
+<A NAME="lbAG">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="pf_key.5.html">pf_key</A>(5), <A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_manual.8.html">ipsec_manual</A>(8), <A HREF="ipsec_eroute.5.html">ipsec_eroute</A>(5), <A HREF="ipsec_spi.5.html">ipsec_spi</A>(5),
+<A HREF="ipsec_spigrp.5.html">ipsec_spigrp</A>(5), <A HREF="ipsec_klipsdebug.5.html">ipsec_klipsdebug</A>(5), <A HREF="ipsec_tncfg.8.html">ipsec_tncfg</A>(8), <A HREF="ipsec_version.5.html">ipsec_version</A>(5)
+<A NAME="lbAH">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Michael Richardson &lt;<A HREF="mailto:mcr@freeswan.org">mcr@freeswan.org</A>&gt;
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">EXAMPLES</A><DD>
+<DT><A HREF="#lbAF">FILES</A><DD>
+<DT><A HREF="#lbAG">SEE ALSO</A><DD>
+<DT><A HREF="#lbAH">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_pluto.8.html b/doc/manpage.d/ipsec_pluto.8.html
new file mode 100644
index 000000000..2e2ce4c2f
--- /dev/null
+++ b/doc/manpage.d/ipsec_pluto.8.html
@@ -0,0 +1,1824 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_PLUTO</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_PLUTO</H1>
+Section: Maintenance Commands (8)<BR>Updated: 28 March 1999<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec pluto - IPsec IKE keying daemon
+<BR>
+
+ipsec whack - control interface for IPSEC keying daemon
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+
+
+<DL COMPACT>
+<DT>
+<B>
+<DD>ipsec pluto
+[--help]
+[--version]
+[--optionsfrom&nbsp;</B><I>filename</I>]
+[--nofork]
+[--stderrlog]
+[--noklips]
+[--uniqueids]
+[<B>--interface</B> <I>interfacename</I>]
+[--ikeport&nbsp;<I>portnumber</I>]
+[--ctlbase&nbsp;<I>path</I>]
+[--secretsfile&nbsp;<I>secrets-file</I>]
+[--adns <I>pathname</I>]
+[--lwdnsq <I>pathname</I>]
+[--perpeerlog]
+[--perpeerlogbase&nbsp;<I>dirname</I>]
+[--debug-none]
+[--debug-all]
+[--debug-raw]
+[--debug-crypt]
+[--debug-parsing]
+[--debug-emitting]
+[--debug-control]
+[--debug-lifecycle]
+[--debug-klips]
+[--debug-dns]
+[--debug-oppo]
+[--debug-private]
+<DT>
+<B>
+<DD>ipsec whack
+[--help]
+[--version]
+<DT>
+
+<DD>ipsec whack
+--name&nbsp;</B><I>connection-name</I>
+<BR>
+
+[--id&nbsp;<I>id</I>] [--host&nbsp;<I>ip-address</I>]
+[--ikeport&nbsp;<I>port-number</I>]
+[--nexthop&nbsp;<I>ip-address</I>]
+[--client&nbsp;<I>subnet</I>]
+[--dnskeyondemand]
+[--updown&nbsp;<I>updown</I>]
+<BR>
+
+--to
+<BR>
+
+[--id&nbsp;<I>id</I>]
+[--host&nbsp;<I>ip-address</I>]
+[--ikeport&nbsp;<I>port-number</I>]
+[--nexthop&nbsp;<I>ip-address</I>]
+[--client&nbsp;<I>subnet</I>]
+[--dnskeyondemand]
+[--updown&nbsp;<I>updown</I>]
+<BR>
+
+[--psk]
+[--rsasig]
+[--encrypt]
+[--authenticate]
+[--compress]
+[--tunnel]
+[--pfs]
+[--disablearrivalcheck]
+[--ipv4]
+[--ipv6]
+[--tunnelipv4]
+[--tunnelipv6]
+[--ikelifetime&nbsp;<I>seconds</I>]
+[--ipseclifetime&nbsp;<I>seconds</I>]
+[--rekeymargin&nbsp;<I>seconds</I>]
+[--rekeyfuzz&nbsp;<I>percentage</I>]
+[--keyingtries&nbsp;<I>count</I>]
+[--dontrekey]
+[--delete]
+[--ctlbase&nbsp;<I>path</I>]
+[--optionsfrom&nbsp;<I>filename</I>]
+[--label&nbsp;<I>string</I>]
+<DT>
+<B>
+<DD>ipsec whack
+--keyid&nbsp;</B><I>id</I>
+[--addkey]
+[--pubkeyrsa&nbsp;<I>key</I>]
+[--ctlbase&nbsp;<I>path</I>]
+[--optionsfrom&nbsp;<I>filename</I>]
+[--label&nbsp;<I>string</I>]
+<DT>
+<B>
+<DD>ipsec whack
+--myid&nbsp;</B><I>id</I>
+<DT>
+<B>
+<DD>ipsec whack
+--listen|--unlisten
+[--ctlbase&nbsp;</B><I>path</I>]
+[--optionsfrom&nbsp;<I>filename</I>]
+[--label&nbsp;<I>string</I>]
+<DT>
+<B>
+<DD>ipsec whack
+--route|--unroute
+--name&nbsp;</B><I>connection-name</I>
+[--ctlbase&nbsp;<I>path</I>]
+[--optionsfrom&nbsp;<I>filename</I>]
+[--label&nbsp;<I>string</I>]
+<DT>
+<B>
+<DD>ipsec whack
+--initiate|--terminate
+--name&nbsp;</B><I>connection-name</I>
+[--asynchronous]
+[--ctlbase&nbsp;<I>path</I>]
+[--optionsfrom&nbsp;<I>filename</I>]
+[--label&nbsp;<I>string</I>]
+<DT>
+<B>
+<DD>ipsec whack
+[--tunnelipv4]
+[--tunnelipv6]
+--oppohere </B><I>ip-address</I>
+--oppothere <I>ip-address</I>
+<DT>
+<B>
+<DD>ipsec whack
+--delete
+--name&nbsp;</B><I>connection-name</I>
+[--ctlbase&nbsp;<I>path</I>]
+[--optionsfrom&nbsp;<I>filename</I>]
+[--label&nbsp;<I>string</I>]
+<DT>
+<B>
+<DD>ipsec whack
+--deletestate&nbsp;</B><I>state-number</I>
+[--ctlbase&nbsp;<I>path</I>]
+[--optionsfrom&nbsp;<I>filename</I>]
+[--label&nbsp;<I>string</I>]
+<DT>
+<B>
+<DD>ipsec whack
+[--name&nbsp;</B><I>connection-name</I>]
+[--debug-none]
+[--debug-all]
+[--debug-raw]
+[--debug-crypt]
+[--debug-parsing]
+[--debug-emitting]
+[--debug-control]
+[--debug-lifecycle]
+[--debug-klips]
+[--debug-dns]
+[--debug-oppo]
+[--debug-private]
+[--ctlbase&nbsp;<I>path</I>]
+[--optionsfrom&nbsp;<I>filename</I>]
+[--label&nbsp;<I>string</I>]
+<DT>
+<B>
+<DD>ipsec whack
+--status
+[--ctlbase&nbsp;</B><I>path</I>]
+[--optionsfrom&nbsp;<I>filename</I>]
+[--label&nbsp;<I>string</I>]
+<DT>
+<B>
+<DD>ipsec whack
+--shutdown
+[--ctlbase&nbsp;</B><I>path</I>]
+[--optionsfrom&nbsp;<I>filename</I>]
+[--label&nbsp;<I>string</I>]
+
+
+
+</DL>
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<B>pluto</B>
+
+is an IKE (``IPsec Key Exchange'') daemon.
+<B>whack</B>
+
+is an auxiliary program to allow requests to be made to a running
+<B>pluto</B>.
+
+<P>
+
+<B>pluto</B>
+
+is used to automatically build shared ``security associations'' on a
+system that has IPsec, the secure IP protocol.
+In other words,
+<B>pluto</B>
+
+can eliminate much of the work of manual keying.
+The actual
+secure transmission of packets is the responsibility of other parts of
+the system (see
+<B>KLIPS</B>,
+
+the companion implementation of IPsec).
+<I><A HREF="ipsec_auto.8.html">ipsec_auto</A></I>(8) provides a more convenient interface to
+<B>pluto</B> and <B>whack</B>.
+<A NAME="lbAE">&nbsp;</A>
+<H3>IKE's Job</H3>
+
+<P>
+
+A <I>Security Association</I> (<I>SA</I>) is an agreement between two network nodes on
+how to process certain traffic between them.  This processing involves
+encapsulation, authentication, encryption, or compression.
+<P>
+
+IKE can be deployed on a network node to negotiate Security
+Associations for that node.  These IKE implementations can only
+negotiate with other IKE implementations, so IKE must be on each node
+that is to be an endpoint of an IKE-negotiated Security Association.
+No other nodes need to be running IKE.
+<P>
+
+An IKE instance (i.e. an IKE implementation on a particular network
+node) communicates with another IKE instance using UDP IP packets, so
+there must be a route between the nodes in each direction.
+<P>
+
+The negotiation of Security Associations requires a number of choices
+that involve tradeoffs between security, convenience, trust, and
+efficiency.  These are policy issues and are normally specified to the
+IKE instance by the system administrator.
+<P>
+
+IKE deals with two kinds of Security Associations.  The first part of
+a negotiation between IKE instances is to build an ISAKMP SA.  An
+ISAKMP SA is used to protect communication between the two IKEs.
+IPsec SAs can then be built by the IKEs - these are used to carry
+protected IP traffic between the systems.
+<P>
+
+The negotiation of the ISAKMP SA is known as Phase 1.  In theory,
+Phase 1 can be accomplished by a couple of different exchange types,
+but we only implement one called Main Mode (we don't implement
+Aggressive Mode).
+<P>
+
+Any negotiation under the protection of an ISAKMP SA, including the
+negotiation of IPsec SAs, is part of Phase 2.  The exchange type
+that we use to negotiate an IPsec SA is called Quick Mode.
+<P>
+
+IKE instances must be able to authenticate each other as part of their
+negotiation of an ISAKMP SA.  This can be done by several mechanisms
+described in the draft standards.
+<P>
+
+IKE negotiation can be initiated by any instance with any other.  If
+both can find an agreeable set of characteristics for a Security
+Association, and both recognize each others authenticity, they can set
+up a Security Association.  The standards do not specify what causes
+an IKE instance to initiate a negotiation.
+<P>
+
+In summary, an IKE instance is prepared to automate the management of
+Security Associations in an IPsec environment, but a number of issues
+are considered policy and are left in the system administrator's hands.
+<A NAME="lbAF">&nbsp;</A>
+<H3>Pluto</H3>
+
+<P>
+
+<B>pluto</B> is an implementation of IKE.  It runs as a daemon on a network
+node.  Currently, this network node must be a LINUX system running the
+<B>KLIPS</B> implementation of IPsec.
+<P>
+
+<B>pluto</B> only implements a subset of IKE.  This is enough for it to
+interoperate with other instances of <B>pluto</B>, and many other IKE
+implementations.  We are working on implementing more of IKE.
+<P>
+
+The policy for acceptable characteristics for Security Associations is
+mostly hardwired into the code of <B>pluto</B> (spdb.c).  Eventually
+this will be moved into a security policy database with reasonable
+expressive power and more convenience.
+<P>
+
+<B>pluto</B> uses shared secrets or RSA signatures to authenticate
+peers with whom it is negotiating.
+<P>
+
+<B>pluto</B> initiates negotiation of a Security Association when it is
+manually prodded: the program <B>whack</B> is run to trigger this.
+It will also initiate a negotiation when <B>KLIPS</B> traps an outbound packet
+for Opportunistic Encryption.
+<P>
+
+<B>pluto</B> implements ISAKMP SAs itself.  After it has negotiated the
+characteristics of an IPsec SA, it directs <B>KLIPS</B> to implement it.
+It also invokes a script to adjust any firewall and issue <I><A HREF="route.8.html">route</A></I>(8)
+commands to direct IP packets through <B>KLIPS</B>.
+<P>
+
+When <B>pluto</B> shuts down, it closes all Security Associations.
+<A NAME="lbAG">&nbsp;</A>
+<H3>Before Running Pluto</H3>
+
+<P>
+
+<B>pluto</B> runs as a daemon with userid root.  Before running it, a few
+things must be set up.
+<P>
+
+<B>pluto</B> requires <B>KLIPS</B>, the FreeS/WAN implementation of IPsec.
+All of the components of <B>KLIPS</B> and <B>pluto</B> should be installed.
+<P>
+
+<B>pluto</B> supports multiple public networks (that is, networks
+that are considered insecure and thus need to have their traffic
+encrypted or authenticated).  It discovers the
+public interfaces to use by looking at all interfaces that are
+configured (the <B>--interface</B> option can be used to limit
+the interfaces considered).
+It does this only when <B>whack</B> tells it to --listen,
+so the interfaces must be configured by then.  Each interface with a name of the form
+<B>ipsec</B>[<B>0</B>-<B>9</B>] is taken as a <B>KLIPS</B> virtual public interface.
+Another network interface with the same IP address (there should be only
+one) is taken as the corresponding real public
+interface.  <I><A HREF="ifconfig.8.html">ifconfig</A></I>(8) with the <B>-a</B> flag will show
+the name and status of each network interface.
+<P>
+
+<B>pluto</B> requires a database of preshared secrets and RSA private keys.
+This is described in the
+<I><A HREF="ipsec.secrets.5.html">ipsec.secrets</A></I>(5).
+
+<B>pluto</B> is told of RSA public keys via <B>whack</B> commands.
+If the connection is Opportunistic, and no RSA public key is known,
+<B>pluto</B> will attempt to fetch RSA keys using the Domain Name System.
+<A NAME="lbAH">&nbsp;</A>
+<H3>Setting up <B>KLIPS</B> for <B>pluto</B></H3>
+
+<P>
+
+The most basic network topology that <B>pluto</B> supports has two security
+gateways negotiating on behalf of client subnets.  The diagram of RGB's
+testbed is a good example (see <I>klips/doc/rgb_setup.txt</I>).
+<P>
+
+The file <I>INSTALL</I> in the base directory of this distribution
+explains how to start setting up the whole system, including <B>KLIPS</B>.
+<P>
+
+Make sure that the security gateways have routes to each other.  This
+is usually covered by the default route, but may require issuing
+<I><A HREF="route.8.html">route</A></I>(8)
+
+commands.  The route must go through a particular IP
+interface (we will assume it is <I>eth0</I>, but it need not be).  The
+interface that connects the security gateway to its client must be a
+different one.
+<P>
+
+It is necessary to issue a
+<I><A HREF="ipsec_tncfg.8.html">ipsec_tncfg</A></I>(8)
+
+command on each gateway.  The required command is:
+<P>
+&nbsp;&nbsp;&nbsp;ipsec tncfg --attach&nbsp;--virtual&nbsp;ipsec0 --physical&nbsp;eth0
+<P>
+A command to set up the ipsec0 virtual interface will also need to be
+run.  It will have the same parameters as the command used to set up
+the physical interface to which it has just been connected using
+<I><A HREF="ipsec_tncfg.8.html">ipsec_tncfg</A></I>(8).
+
+<A NAME="lbAI">&nbsp;</A>
+<H3>ipsec.secrets file</H3>
+
+<P>
+
+A <B>pluto</B> daemon and another IKE daemon (for example, another instance
+of <B>pluto</B>) must convince each other that they are who they are supposed
+to be before any negotiation can succeed.  This authentication is
+accomplished by using either secrets that have been shared beforehand
+(manually) or by using RSA signatures.  There are other techniques,
+but they have not been implemented in <B>pluto</B>.
+<P>
+
+The file <I>/etc/ipsec.secrets</I> is used to keep preshared secret keys
+and RSA private keys for
+authentication with other IKE daemons.  For debugging, there is an
+argument to the <B>pluto</B> command to use a different file.
+This file is described in
+<I><A HREF="ipsec.secrets.5.html">ipsec.secrets</A></I>(5).
+
+<A NAME="lbAJ">&nbsp;</A>
+<H3>Running Pluto</H3>
+
+<P>
+
+To fire up the daemon, just type <B>pluto</B> (be sure to be running as
+the superuser).
+The default IKE port number is 500, the UDP port assigned by IANA for IKE Daemons.
+<B>pluto</B> must be run by the superuser to be able to use the UDP 500 port.
+<P>
+
+<B>pluto</B> attempts to create a lockfile with the name
+<I>/var/run/pluto.pid</I>.  If the lockfile cannot be created,
+<B>pluto</B> exits - this prevents multiple <B>pluto</B>s from
+competing  Any ``leftover'' lockfile must be removed before
+<B>pluto</B> will run.  <B>pluto</B> writes its pid into this file so
+that scripts can find it.  This lock will not function properly if it
+is on an NFS volume (but sharing locks on multiple machines doesn't
+make sense anyway).
+<P>
+
+<B>pluto</B> then forks and the parent exits.  This is the conventional
+``daemon fork''.  It can make debugging awkward, so there is an option
+to suppress this fork.
+<P>
+
+All logging, including diagnostics, is sent to
+<I><A HREF="syslog.3.html">syslog</A></I>(3)
+
+with facility=authpriv;
+it decides where to put these messages (possibly in /var/log/secure).
+Since this too can make debugging awkward, there is an option to
+steer logging to stderr.
+<P>
+
+If the <B>--perpeerlog</B> option is given, then pluto will open
+a log file per connection. By default, this is in /var/log/pluto/peer,
+in a subdirectory formed by turning all dot (.) [IPv4} or colon (:)
+[IPv6] into slashes (/).
+<P>
+
+The base directory can be changed with the <B>--perpeerlogbase</B>.
+<P>
+
+Once <B>pluto</B> is started, it waits for requests from <B>whack</B>.
+<A NAME="lbAK">&nbsp;</A>
+<H3>Pluto's Internal State</H3>
+
+<P>
+
+To understand how to use <B>pluto</B>, it is helpful to understand a little
+about its internal state.  Furthermore, the terminology is needed to decipher
+some of the diagnostic messages.
+<P>
+
+The <I>(potential) connection</I> database describes attributes of a
+connection.  These include the IP addresses of the hosts and client
+subnets and the security characteristics desired.  <B>pluto</B>
+requires this information (simply called a connection) before it can
+respond to a request to build an SA.  Each connection is given a name
+when it is created, and all references are made using this name.
+<P>
+
+During the IKE exchange to build an SA, the information about the
+negotiation is represented in a <I>state object</I>.  Each state object
+reflects how far the negotiation has reached.  Once the negotiation is
+complete and the SA established, the state object remains to represent
+the SA.  When the SA is terminated, the state object is discarded.
+Each State object is given a serial number and this is used to refer
+to the state objects in logged messages.
+<P>
+
+Each state object corresponds to a connection and can be thought of
+as an instantiation of that connection.
+At any particular time, there may be any number of state objects
+corresponding to a particular connection.
+Often there is one representing an ISAKMP SA and another representing
+an IPsec SA.
+<P>
+
+<B>KLIPS</B> hooks into the routing code in a LINUX kernel.
+Traffic to be processed by an IPsec SA must be directed through
+<B>KLIPS</B> by routing commands.  Furthermore, the processing to be
+done is specified by <I>ipsec <A HREF="eroute.8.html">eroute</A>(8)</I> commands.
+<B>pluto</B> takes the responsibility of managing both of these special
+kinds of routes.
+<P>
+
+Each connection may be routed, and must be while it has an IPsec SA.
+The connection specifies the characteristics of the route: the
+interface on this machine, the ``gateway'' (the nexthop),
+and the peer's client subnet.  Two
+connections may not be simultaneously routed if they are for the same
+peer's client subnet but use different interfaces or gateways
+(<B>pluto</B>'s logic does not reflect any advanced routing capabilities).
+<P>
+
+Each eroute is associated with the state object for an IPsec SA
+because it has the particular characteristics of the SA.
+Two eroutes conflict if they specify the identical local
+and remote clients (unlike for routes, the local clients are
+taken into account).
+<P>
+
+When <B>pluto</B> needs to install a route for a connection,
+it must make sure that no conflicting route is in use.  If another
+connection has a conflicting route, that route will be taken down, as long
+as there is no IPsec SA instantiating that connection.
+If there is such an IPsec SA, the attempt to install a route will fail.
+<P>
+
+There is an exception.  If <B>pluto</B>, as Responder, needs to install
+a route to a fixed client subnet for a connection, and there is
+already a conflicting route, then the SAs using the route are deleted
+to make room for the new SAs.  The rationale is that the new
+connection is probably more current.  The need for this usually is a
+product of Road Warrior connections (these are explained later; they
+cannot be used to initiate).
+<P>
+
+When <B>pluto</B> needs to install an eroute for an IPsec SA (for a
+state object), first the state object's connection must be routed (if
+this cannot be done, the eroute and SA will not be installed).
+If a conflicting eroute is already in place for another connection,
+the eroute and SA will not be installed (but note that the routing
+exception mentioned above may have already deleted potentially conflicting SAs).
+If another IPsec
+SA for the same connection already has an eroute, all its outgoing traffic
+is taken over by the new eroute.  The incoming traffic will still be
+processed.  This characteristic is exploited during rekeying.
+<P>
+
+All of these routing characteristics are expected change when
+<B>KLIPS</B> is modified to use the firewall hooks in the LINUX 2.4.x
+kernel.
+<A NAME="lbAL">&nbsp;</A>
+<H3>Using Whack</H3>
+
+<P>
+
+<B>whack</B> is used to command a running <B>pluto</B>.
+<B>whack</B> uses a UNIX domain socket to speak to <B>pluto</B>
+(by default, <I>/var/pluto.ctl</I>).
+<P>
+
+<B>whack</B> has an intricate argument syntax.
+This syntax allows many different functions to be specified.
+The help form shows the usage or version information.
+The connection form gives <B>pluto</B> a description of a potential connection.
+The public key form informs <B>pluto</B> of the RSA public key for a potential peer.
+The delete form deletes a connection description and all SAs corresponding
+to it.
+The listen form tells <B>pluto</B> to start or stop listening on the public interfaces
+for IKE requests from peers.
+The route form tells <B>pluto</B> to set up routing for a connection;
+the unroute form undoes this.
+The initiate form tells <B>pluto</B> to negotiate an SA corresponding to a connection.
+The terminate form tells <B>pluto</B> to remove all SAs corresponding to a connection,
+including those being negotiated.
+The status form displays the <B>pluto</B>'s internal state.
+The debug form tells <B>pluto</B> to change the selection of debugging output
+``on the fly''.  The shutdown form tells
+<B>pluto</B> to shut down, deleting all SAs.
+<P>
+
+Most options are specific to one of the forms, and will be described
+with that form.  There are three options that apply to all forms.
+<DL COMPACT>
+<DT><B>--ctlbase</B>&nbsp;<I>path</I><DD>
+<I>path</I>.ctl is used as the UNIX domain socket for talking
+to <B>pluto</B>.
+This option facilitates debugging.
+<DT><B>--optionsfrom</B>&nbsp;<I>filename</I><DD>
+adds the contents of the file to the argument list.
+<DT><B>--label</B>&nbsp;<I>string</I><DD>
+adds the string to all error messages generated by <B>whack</B>.
+</DL>
+<P>
+
+The help form of <B>whack</B> is self-explanatory.
+<DL COMPACT>
+<DT><B>--help</B><DD>
+display the usage message.
+<DT><B>--version</B><DD>
+display the version of <B>whack</B>.
+</DL>
+<P>
+
+The connection form describes a potential connection to <B>pluto</B>.
+<B>pluto</B> needs to know what connections can and should be negotiated.
+When <B>pluto</B> is the initiator, it needs to know what to propose.
+When <B>pluto</B> is the responder, it needs to know enough to decide whether
+is is willing to set up the proposed connection.
+<P>
+
+The description of a potential connection can specify a large number
+of details.  Each connection has a unique name.  This name will appear
+in a updown shell command, so it should not contain punctuation
+that would make the command ill-formed.
+<DL COMPACT>
+<DT><B>--name</B>&nbsp;<I>connection-name</I><DD>
+</DL>
+<P>
+
+The topology of
+a connection is symmetric, so to save space here is half a picture:
+<P>
+&nbsp;&nbsp;&nbsp;client_subnet&lt;--&gt;host:ikeport&lt;--&gt;nexthop&lt;---
+<P>
+A similar trick is used in the flags.  The same flag names are used for
+both ends.  Those before the <B>--to</B> flag describe the left side
+and those afterwards describe the right side.  When <B>pluto</B> attempts
+to use the connection, it decides whether it is the left side or the right
+side of the connection, based on the IP numbers of its interfaces.
+<DL COMPACT>
+<DT><B>--id</B>&nbsp;<I>id</I><DD>
+the identity of the end.  Currently, this can be an IP address (specified
+as dotted quad or as a Fully Qualified Domain Name, which will be resolved
+immediately) or as a Fully Qualified Domain Name itself (prefixed by ``@''
+to signify that it should not be resolved), or as <A HREF="mailto:user@FQDN">user@FQDN</A>, or as the
+magic value <B>%myid</B>.
+<B>Pluto</B> only authenticates the identity, and does not use it for
+addressing, so, for example, an IP address need not be the one to which
+packets are to be sent.  If the option is absent, the
+identity defaults to the IP address specified by <B>--host</B>.
+<B>%myid</B> allows the identity to be separately specified (by the <B>pluto</B> or <B>whack</B> option <B>--myid</B>
+or by the <B><A HREF="ipsec.conf.5.html">ipsec.conf</A></B>(5) <B>config setup</B> parameter myid).
+Otherwise, <B>pluto</B> tries to guess what <B>%myid</B> should stand for:
+the IP address of <B>%defaultroute</B>, if it is supported by a suitable TXT record in the reverse domain for that IP address,
+or the system's hostname, if it is supported by a suitable TXT record in its forward domain.
+
+<DT><B>--host</B>&nbsp;<I>ip-address</I><DD>
+<DT><B>--host</B>&nbsp;<B>%any</B><DD>
+<DT><B>--host</B>&nbsp;<B>%opportunistic</B><DD>
+the IP address of the end (generally the public interface).
+If <B>pluto</B> is to act as a responder
+for IKE negotiations initiated from unknown IP addresses (the
+``Road Warrior'' case), the
+IP address should be specified as <B>%any</B> (currently,
+the obsolete notation <B>0.0.0.0</B> is also accepted for this).
+If <B>pluto</B> is to opportunistically initiate the connection,
+use <B>%opportunistic</B>
+<DT><B>--ikeport</B>&nbsp;<I>port-number</I><DD>
+the UDP port that IKE listens to on that host.  The default is 500.
+(<B>pluto</B> on this machine uses the port specified by its own command
+line argument, so this only affects where <B>pluto</B> sends messages.)
+<DT><B>--nexthop</B>&nbsp;<I>ip-address</I><DD>
+where to route packets for the peer's client (presumably for the peer too,
+but it will not be used for this).
+When <B>pluto</B> installs an IPsec SA, it issues a route command.
+It uses the nexthop as the gateway.
+The default is the peer's IP address (this can be explicitly written as
+<B>%direct</B>; the obsolete notation <B>0.0.0.0</B> is accepted).
+This option is necessary if <B>pluto</B>'s host's interface used for sending
+packets to the peer is neither point-to-point nor directly connected to the
+peer.
+<DT><B>--client</B>&nbsp;<I>subnet</I><DD>
+the subnet for which the IPsec traffic will be destined.  If not specified,
+the host will be the client.
+The subnet can be specified in any of the forms supported by <I><A HREF="ipsec_atosubnet.3.html">ipsec_atosubnet</A></I>(3).
+The general form is <I>address</I>/<I>mask</I>.  The <I>address</I> can be either
+a domain name or four decimal numbers (specifying octets) separated by dots.
+The most convenient form of the <I>mask</I> is a decimal integer, specifying
+the number of leading one bits in the mask.  So, for example, 10.0.0.0/8
+would specify the class A network ``Net 10''.
+<DT><B>--dnskeyondemand]</B><DD>
+specifies that when an RSA public key is needed to authenticate this
+host, and it isn't already known, fetch it from DNS.
+<DT><B>--updown</B>&nbsp;<I>updown</I><DD>
+specifies an external shell command to be run whenever <B>pluto</B>
+brings up or down a connection.
+The script is used to build a shell command, so it may contain positional
+parameters, but ought not to have punctuation that would cause the
+resulting command to be ill-formed.
+The default is <I>ipsec _updown</I>.
+<DT><B>--to</B><DD>
+separates the specification of the left and right ends of the connection.
+</DL>
+<P>
+
+The potential connection description also specifies characteristics of
+rekeying and security.
+<DL COMPACT>
+<DT><B>--psk</B><DD>
+Propose and allow preshared secret authentication for IKE peers.  This authentication
+requires that each side use the same secret.  May be combined with <B>--rsasig</B>;
+at least one must be specified.
+<DT><B>--rsasig</B><DD>
+Propose and allow RSA signatures for authentication of IKE peers.  This authentication
+requires that each side have have a private key of its own and know the
+public key of its peer.  May be combined with <B>--psk</B>;
+at least one must be specified.
+<DT><B>--encrypt</B><DD>
+All proposed or accepted IPsec SAs will include non-null ESP.
+The actual choices of transforms are wired into <B>pluto</B>.
+<DT><B>--authenticate</B><DD>
+All proposed IPsec SAs will include AH.
+All accepted IPsec SAs will include AH or ESP with authentication.
+The actual choices of transforms are wired into <B>pluto</B>.
+Note that this has nothing to do with IKE authentication.
+<DT><B>--compress</B><DD>
+All proposed IPsec SAs will include IPCOMP (compression).
+This will be ignored if KLIPS is not configured with IPCOMP support.
+<DT><B>--tunnel</B><DD>
+the IPsec SA should use tunneling.  Implicit if the SA is for clients.
+Must only be used with <B>--authenticate</B> or <B>--encrypt</B>.
+<DT><B>--ipv4</B><DD>
+The host addresses will be interpreted as IPv4 addresses.  This is the
+default.  Note that for a connection, all host addresses must be of
+the same Address Family (IPv4 and IPv6 use different Address Families).
+<DT><B>--ipv6</B><DD>
+The host addresses (including nexthop) will be interpreted as IPv6 addresses.
+Note that for a connection, all host addresses must be of
+the same Address Family (IPv4 and IPv6 use different Address Families).
+<DT><B>--tunnelipv4</B><DD>
+The client addresses will be interpreted as IPv4 addresses.  The default is
+to match what the host will be.  This does not imply <B>--tunnel</B> so the
+flag can be safely used when no tunnel is actually specified.
+Note that for a connection, all tunnel addresses must be of the same
+Address Family.
+<DT><B>--tunnelipv6</B><DD>
+The client addresses will be interpreted as IPv6 addresses.  The default is
+to match what the host will be.  This does not imply <B>--tunnel</B> so the
+flag can be safely used when no tunnel is actually specified.
+Note that for a connection, all tunnel addresses must be of the same
+Address Family.
+<DT><B>--pfs</B><DD>
+There should be Perfect Forward Secrecy - new keying material will
+be generated for each IPsec SA rather than being derived from the ISAKMP
+SA keying material.
+Since the group to be used cannot be negotiated (a dubious feature of the
+standard), <B>pluto</B> will propose the same group that was used during Phase 1.
+We don't implement a stronger form of PFS which would require that the
+ISAKMP SA be deleted after the IPSEC SA is negotiated.
+<DT><B>--disablearrivalcheck</B><DD>
+If the connection is a tunnel, allow packets arriving through the tunnel
+to have any source and destination addresses.
+</DL>
+<P>
+
+If none of the <B>--encrypt</B>, <B>--authenticate</B>, <B>--compress</B>,
+or <B>--pfs</B> flags is given, the initiating the connection will
+only build an ISAKMP SA.  For such a connection, client subnets have
+no meaning and must not be specified.
+<P>
+
+More work is needed to allow for flexible policies.  Currently
+policy is hardwired in the source file spdb.c.  The ISAKMP SAs may use
+Oakley groups MODP1024 and MODP1536; 3DES encryption; SHA1-96
+and MD5-96 authentication.  The IPsec SAs may use 3DES and
+MD5-96 or SHA1-96 for ESP, or just MD5-96 or SHA1-96 for AH.
+IPCOMP Compression is always Deflate.
+<DL COMPACT>
+<DT><B>--ikelifetime</B>&nbsp;<I>seconds</I><DD>
+how long <B>pluto</B> will propose that an ISAKMP SA be allowed to live.
+The default is 3600 (one hour) and the maximum is 28800 (8 hours).
+This option will not affect what is accepted.
+<B>pluto</B> will reject proposals that exceed the maximum.
+<DT><B>--ipseclifetime</B>&nbsp;<I>seconds</I><DD>
+how long <B>pluto</B> will propose that an IPsec SA be allowed to live.
+The default is 28800 (eight hours) and the maximum is 86400 (one day).
+This option will not affect what is accepted.
+<B>pluto</B> will reject proposals that exceed the maximum.
+<DT><B>--rekeymargin</B>&nbsp;<I>seconds</I><DD>
+how long before an SA's expiration should <B>pluto</B> try to negotiate
+a replacement SA.  This will only happen if <B>pluto</B> was the initiator.
+The default is 540 (nine minutes).
+<DT><B>--rekeyfuzz</B>&nbsp;<I>percentage</I><DD>
+maximum size of random component to add to rekeymargin, expressed as
+a percentage of rekeymargin.  <B>pluto</B> will select a delay uniformly
+distributed within this range.  By default, the percentage will be 100.
+If greater determinism is desired, specify 0.  It may be appropriate
+for the percentage to be much larger than 100.
+<DT><B>--keyingtries</B>&nbsp;<I>count</I><DD>
+how many times <B>pluto</B> should try to negotiate an SA,
+either for the first time or for rekeying.
+A value of 0 is interpreted as a very large number: never give up.
+The default is three.
+<DT><B>--dontrekey</B><DD>
+A misnomer.
+Only rekey a connection if we were the Initiator and there was recent
+traffic on the existing connection.
+This applies to Phase 1 and Phase 2.
+This is currently the only automatic way for a connection to terminate.
+It may be useful with Road Warrior or Opportunistic connections.
+<BR>
+
+Since SA lifetime negotiation is take-it-or-leave it, a Responder
+normally uses the shorter of the negotiated or the configured lifetime.
+This only works because if the lifetime is shorter than negotiated,
+the Responder will rekey in time so that everything works.
+This interacts badly with <B>--dontrekey</B>.  In this case,
+the Responder will end up rekeying to rectify a shortfall in an IPsec SA
+lifetime; for an ISAKMP SA, the Responder will accept the negotiated
+lifetime.
+<DT><B>--delete</B><DD>
+when used in the connection form, it causes any previous connection
+with this name to be deleted before this one is added.  Unlike a
+normal delete, no diagnostic is produced if there was no previous
+connection to delete.  Any routing in place for the connection is undone.
+</DL>
+<P>
+
+The delete form deletes a named connection description and any
+SAs established or negotiations initiated using this connection.
+Any routing in place for the connection is undone.
+<DL COMPACT>
+<DT><B>--delete</B><DD>
+<DT><B>--name</B>&nbsp;<I>connection-name</I><DD>
+</DL>
+<P>
+
+The deletestate form deletes the state object with the specified serial number.
+This is useful for selectively deleting instances of connections.
+<DL COMPACT>
+<DT><B>--deletestate</B>&nbsp;<I>state-number</I><DD>
+</DL>
+<P>
+
+The route form of the <B>whack</B> command tells <B>pluto</B> to set up
+routing for a connection.
+Although like a traditional route, it uses an ipsec device as a
+virtual interface.
+Once routing is set up, no packets will be
+sent ``in the clear'' to the peer's client specified in the connection.
+A TRAP shunt eroute will be installed; if outbound traffic is caught,
+Pluto will initiate the connection.
+An explicit <B>whack</B> route is not always needed: if it hasn't been
+done when an IPsec SA is being installed, one will be automatically attempted.
+<P>
+
+When a routing is attempted for a connection, there must not already
+be a routing for a different connection with the same subnet but different
+interface or destination, or if
+there is, it must not be being used by an IPsec SA.  Otherwise the
+attempt will fail.
+<DL COMPACT>
+<DT><B>--route</B><DD>
+<DT><B>--name</B>&nbsp;<I>connection-name</I><DD>
+</DL>
+<P>
+
+The unroute form of the <B>whack</B> command tells <B>pluto</B> to undo
+a routing.  <B>pluto</B> will refuse if an IPsec SA is using the connection.
+If another connection is sharing the same routing, it will be left in place.
+Without a routing, packets will be sent without encryption or authentication.
+<DL COMPACT>
+<DT><B>--unroute</B><DD>
+<DT><B>--name</B>&nbsp;<I>connection-name</I><DD>
+</DL>
+<P>
+
+The initiate form tells <B>pluto</B> to initiate a negotiation with another
+<B>pluto</B> (or other IKE daemon) according to the named connection.
+Initiation requires a route that <B>--route</B> would provide;
+if none is in place at the time an IPsec SA is being installed,
+<B>pluto</B> attempts to set one up.
+<DL COMPACT>
+<DT><B>--initiate</B><DD>
+<DT><B>--name</B>&nbsp;<I>connection-name</I><DD>
+<DT><B>--asynchronous<DD>
+</DL>
+<P>
+
+The initiate form of the whack</B> command will relay back from
+<B>pluto</B> status information via the UNIX domain socket (unless
+--asynchronous is specified).  The status information is meant to
+look a bit like that from <B>FTP</B>.  Currently <B>whack</B> simply
+copies this to stderr.  When the request is finished (eg. the SAs are
+established or <B>pluto</B> gives up), <B>pluto</B> closes the channel,
+causing <B>whack</B> to terminate.
+<P>
+
+The opportunistic initiate form is mainly used for debugging.
+<DL COMPACT>
+<DT><B>--tunnelipv4</B><DD>
+<DT><B>--tunnelipv6</B><DD>
+<DT><B>--oppohere</B>&nbsp;<I>ip-address</I><DD>
+<DT><B>--oppothere</B>&nbsp;<I>ip-address</I><DD>
+</DL>
+<P>
+
+This will cause <B>pluto</B> to attempt to opportunistically initiate a
+connection from here to the there, even if a previous attempt
+had been made.
+The whack log will show the progress of this attempt.
+<P>
+
+The terminate form tells <B>pluto</B> to delete any SAs that use the specified
+connection and to stop any negotiations in process.
+It does not prevent new negotiations from starting (the delete form
+has this effect).
+<DL COMPACT>
+<DT><B>--terminate</B><DD>
+<DT><B>--name</B>&nbsp;<I>connection-name</I><DD>
+</DL>
+<P>
+
+The public key for informs <B>pluto</B> of the RSA public key for a potential peer.
+Private keys must be kept secret, so they are kept in
+<I><A HREF="ipsec.secrets.5.html">ipsec.secrets</A></I>(5).
+
+<DL COMPACT>
+<DT><B>--keyid&nbsp;</B><I>id</I><DD>
+specififies the identity of the peer for which a public key should be used.
+Its form is identical to the identity in the connection.
+If no public key is specified, <B>pluto</B> attempts to find KEY records
+from DNS for the id (if a FQDN) or through reverse lookup (if an IP address).
+Note that there several interesting ways in which this is not secure.
+<DT><B>--addkey</B><DD>
+specifies that the new key is added to the collection; otherwise the
+new key replaces any old ones.
+<DT><B>--pubkeyrsa&nbsp;</B><I>key</I><DD>
+specifies the value of the RSA public key.  It is a sequence of bytes
+as described in RFC 2537 ``RSA/MD5 KEYs and SIGs in the Domain Name System (DNS)''.
+It is denoted in a way suitable for <I><A HREF="ipsec_ttodata.3.html">ipsec_ttodata</A></I>(3).
+For example, a base 64 numeral starts with 0s.
+</DL>
+<P>
+
+The listen form tells <B>pluto</B> to start listening for IKE requests
+on its public interfaces.  To avoid race conditions, it is normal to
+load the appropriate connections into <B>pluto</B> before allowing it
+to listen.  If <B>pluto</B> isn't listening, it is pointless to
+initiate negotiations, so it will refuse requests to do so.  Whenever
+the listen form is used, <B>pluto</B> looks for public interfaces and
+will notice when new ones have been added and when old ones have been
+removed.  This is also the trigger for <B>pluto</B> to read the
+<I>ipsec.secrets</I> file.  So listen may useful more than once.
+<DL COMPACT>
+<DT><B>--listen</B><DD>
+start listening for IKE traffic on public interfaces.
+<DT><B>--unlisten</B><DD>
+stop listening for IKE traffic on public interfaces.
+</DL>
+<P>
+
+The status form will display information about the internal state of
+<B>pluto</B>: information about each potential connection, about
+each state object, and about each shunt that <B>pluto</B> is managing
+without an associated connection.
+<DL COMPACT>
+<DT><B>--status</B><DD>
+</DL>
+<P>
+
+The shutdown form is the proper way to shut down <B>pluto</B>.
+It will tear down the SAs on this machine that <B>pluto</B> has negotiated.
+It does not inform its peers, so the SAs on their machines remain.
+<DL COMPACT>
+<DT><B>--shutdown</B><DD>
+</DL>
+<A NAME="lbAM">&nbsp;</A>
+<H3>Examples</H3>
+
+<P>
+
+It would be normal to start <B>pluto</B> in one of the system initialization
+scripts.  It needs to be run by the superuser.  Generally, no arguments are needed.
+To run in manually, the superuser can simply type
+<P>
+&nbsp;&nbsp;&nbsp;ipsec pluto
+<P>
+The command will immediately return, but a <B>pluto</B> process will be left
+running, waiting for requests from <B>whack</B> or a peer.
+<P>
+
+Using <B>whack</B>, several potential connections would be described:
+<DL COMPACT>
+<DT>
+
+&nbsp;&nbsp;&nbsp;ipsec whack --name&nbsp;silly
+--host&nbsp;127.0.0.1 --to --host&nbsp;127.0.0.2
+--ikelifetime&nbsp;900 --ipseclifetime&nbsp;800 --keyingtries&nbsp;3
+
+</DL>
+<P>
+
+<DD>Since this silly connection description specifies neither encryption,
+authentication, nor tunneling, it could only be used to establish
+an ISAKMP SA.
+<DL COMPACT>
+<DT>
+
+&nbsp;&nbsp;&nbsp;ipsec whack --name&nbsp;secret --host&nbsp;10.0.0.1 --client&nbsp;10.0.1.0/24
+--to --host&nbsp;10.0.0.2 --client&nbsp;10.0.2.0/24
+--encrypt
+
+</DL>
+<P>
+
+<DD>This is something that must be done on both sides.  If the other
+side is <B>pluto</B>, the same <B>whack</B> command could be used on it
+(the command syntax is designed to not distinguish which end is ours).
+<P>
+
+Now that the connections are specified, <B>pluto</B> is ready to handle
+requests and replies via the public interfaces.  We must tell it to discover
+those interfaces and start accepting messages from peers:
+<P>
+&nbsp;&nbsp;&nbsp;ipsec whack --listen
+<P>
+
+If we don't immediately wish to bring up a secure connection between
+the two clients, we might wish to prevent insecure traffic.
+The routing form asks <B>pluto</B> to cause the packets sent from
+our client to the peer's client to be routed through the ipsec0
+device; if there is no SA, they will be discarded:
+<P>
+&nbsp;&nbsp;&nbsp;ipsec whack --route secret
+<P>
+
+Finally, we are ready to get <B>pluto</B> to initiate negotiation
+for an IPsec SA (and implicitly, an ISAKMP SA):
+<P>
+&nbsp;&nbsp;&nbsp;ipsec whack --initiate&nbsp;--name&nbsp;secret
+<P>
+A small log of interesting events will appear on standard output
+(other logging is sent to syslog).
+<P>
+
+<B>whack</B> can also be used to terminate <B>pluto</B> cleanly, tearing down
+all SAs that it has negotiated.
+<P>
+&nbsp;&nbsp;&nbsp;ipsec whack --shutdown
+<P>
+Notification of any IPSEC SA deletion, but not ISAKMP SA deletion
+is sent to the peer.  Unfortunately, such Notification is not reliable.
+Furthermore, <B>pluto</B> itself ignores Notifications.
+<A NAME="lbAN">&nbsp;</A>
+<H3>The updown command</H3>
+
+<P>
+
+Whenever <B>pluto</B> brings a connection up or down, it invokes
+the updown command.  This command is specified using the <B>--updown</B>
+option.  This allows for customized control over routing and firewall manipulation.
+<P>
+
+The updown is invoked for five different operations.  Each of
+these operations can be for our client subnet or for our host itself.
+<DL COMPACT>
+<DT><B>prepare-host</B> or <B>prepare-client</B><DD>
+is run before bringing up a new connection if no other connection
+with the same clients is up.  Generally, this is useful for deleting a
+route that might have been set up before <B>pluto</B> was run or
+perhaps by some agent not known to <B>pluto</B>.
+<DT><B>route-host</B> or <B>route-client</B><DD>
+is run when bringing up a connection for a new peer client subnet
+(even if <B>prepare-host</B> or <B>prepare-client</B> was run).  The
+command should install a suitable route.  Routing decisions are based
+only on the destination (peer's client) subnet address, unlike eroutes
+which discriminate based on source too.
+<DT><B>unroute-host</B> or <B>unroute-client</B><DD>
+is run when bringing down the last connection for a particular peer
+client subnet.  It should undo what the <B>route-host</B> or <B>route-client</B>
+did.
+<DT><B>up-host</B> or <B>up-client</B><DD>
+is run when bringing up a tunnel eroute with a pair of client subnets
+that does not already have a tunnel eroute.
+This command should install firewall rules as appropriate.
+It is generally a good idea to allow IKE messages (UDP port 500)
+travel between the hosts.
+<DT><B>down-host</B> or <B>down-client</B><DD>
+is run when bringing down the eroute for a pair of client subnets.
+This command should delete firewall rules as appropriate.  Note that
+there may remain some inbound IPsec SAs with these client subnets.
+</DL>
+<P>
+
+The script is passed a large number of environment variables to specify
+what needs to be done.
+<DL COMPACT>
+<DT><B>PLUTO_VERSION</B><DD>
+indicates what version of this interface is being used.  This document
+describes version 1.1.  This is upwardly compatible with version 1.0.
+<DT><B>PLUTO_VERB</B><DD>
+specifies the name of the operation to be performed
+(<B>prepare-host</B>,r <B>prepare-client</B>,
+<B>up-host</B>, <B>up-client</B>,
+<B>down-host</B>, or <B>down-client</B>).  If the address family for
+security gateway to security gateway communications is IPv6, then
+a suffix of -v6 is added to the verb.
+<DT><B>PLUTO_CONNECTION</B><DD>
+is the name of the connection for which we are routing.
+<DT><B>PLUTO_NEXT_HOP</B><DD>
+is the next hop to which packets bound for the peer must be sent.
+<DT><B>PLUTO_INTERFACE</B><DD>
+is the name of the ipsec interface to be used.
+<DT><B>PLUTO_ME</B><DD>
+is the IP address of our host.
+<DT><B>PLUTO_MY_CLIENT</B><DD>
+is the IP address / count of our client subnet.
+If the client is just the host, this will be the host's own IP address / max
+(where max is 32 for IPv4 and 128 for IPv6).
+<DT><B>PLUTO_MY_CLIENT_NET</B><DD>
+is the IP address of our client net.
+If the client is just the host, this will be the host's own IP address.
+<DT><B>PLUTO_MY_CLIENT_MASK</B><DD>
+is the mask for our client net.
+If the client is just the host, this will be 255.255.255.255.
+<DT><B>PLUTO_PEER</B><DD>
+is the IP address of our peer.
+<DT><B>PLUTO_PEER_CLIENT</B><DD>
+is the IP address / count of the peer's client subnet.
+If the client is just the peer, this will be the peer's own IP address / max
+(where max is 32 for IPv4 and 128 for IPv6).
+<DT><B>PLUTO_PEER_CLIENT_NET</B><DD>
+is the IP address of the peer's client net.
+If the client is just the peer, this will be the peer's own IP address.
+<DT><B>PLUTO_PEER_CLIENT_MASK</B><DD>
+is the mask for the peer's client net.
+If the client is just the peer, this will be 255.255.255.255.
+</DL>
+<P>
+
+All output sent by the script to stderr or stdout is logged.  The
+script should return an exit status of 0 if and only if it succeeds.
+<P>
+
+<B>Pluto</B> waits for the script to finish and will not do any other
+processing while it is waiting.
+The script may assume that <B>pluto</B> will not change anything
+while the script runs.
+The script should avoid doing anything that takes much time and it
+should not issue any command that requires processing by <B>pluto</B>.
+Either of these activities could be performed by a background
+subprocess of the script.
+<A NAME="lbAO">&nbsp;</A>
+<H3>Rekeying</H3>
+
+<P>
+
+When an SA that was initiated by <B>pluto</B> has only a bit of
+lifetime left,
+<B>pluto</B> will initiate the creation of a new SA.  This applies to
+ISAKMP and IPsec SAs.
+The rekeying will be initiated when the SA's remaining lifetime is
+less than the rekeymargin plus a random percentage, between 0 and
+rekeyfuzz, of the rekeymargin.
+<P>
+
+Similarly, when an SA that was initiated by the peer has only a bit of
+lifetime left, <B>pluto</B> will try to initiate the creation of a
+replacement.
+To give preference to the initiator, this rekeying will only be initiated
+when the SA's remaining lifetime is half of rekeymargin.
+If rekeying is done by the responder, the roles will be reversed: the
+responder for the old SA will be the initiator for the replacement.
+The former initiator might also initiate rekeying, so there may
+be redundant SAs created.
+To avoid these complications, make sure that rekeymargin is generous.
+<P>
+
+One risk of having the former responder initiate is that perhaps
+none of its proposals is acceptable to the former initiator
+(they have not been used in a successful negotiation).
+To reduce the chances of this happening, and to prevent loss of security,
+the policy settings are taken from the old SA (this is the case even if
+the former initiator is initiating).
+These may be stricter than those of the connection.
+<P>
+
+<B>pluto</B> will not rekey an SA if that SA is not the most recent of its
+type (IPsec or ISAKMP) for its potential connection.
+This avoids creating redundant SAs.
+<P>
+
+The random component in the rekeying time (rekeyfuzz) is intended to
+make certain pathological patterns of rekeying unstable.  If both
+sides decide to rekey at the same time, twice as many SAs as necessary
+are created.  This could become a stable pattern without the
+randomness.
+<P>
+
+Another more important case occurs when a security gateway has SAs
+with many other security gateways.  Each of these connections might
+need to be rekeyed at the same time.  This would cause a high peek
+requirement for resources (network bandwidth, CPU time, entropy for
+random numbers).  The rekeyfuzz can be used to stagger the rekeying
+times.
+<P>
+
+Once a new set of SAs has been negotiated, <B>pluto</B> will never send
+traffic on a superseded one.  Traffic will be accepted on an old SA
+until it expires.
+<A NAME="lbAP">&nbsp;</A>
+<H3>Selecting a Connection When Responding: Road Warrior Support</H3>
+
+<P>
+
+When <B>pluto</B> receives an initial Main Mode message, it needs to
+decide which connection this message is for.  It picks based solely on
+the source and destination IP addresses of the message.  There might
+be several connections with suitable IP addresses, in which case one
+of them is arbitrarily chosen.  (The ISAKMP SA proposal contained in
+the message could be taken into account, but it is not.)
+<P>
+
+The ISAKMP SA is negotiated before the parties pass further
+identifying information, so all ISAKMP SA characteristics specified in
+the connection description should be the same for every connection
+with the same two host IP addresses.  At the moment, the only
+characteristic that might differ is authentication method.
+<P>
+
+Up to this point,
+all configuring has presumed that the IP addresses
+are known to all parties ahead of time.  This will not work
+when either end is mobile (or assigned a dynamic IP address for other
+reasons).  We call this situation ``Road Warrior''.  It is fairly tricky
+and has some important limitations, most of which are features of
+the IKE protocol.
+<P>
+
+Only the initiator may be mobile:
+the initiator may have an IP number unknown to the responder.  When
+the responder doesn't recognize the IP address on the first Main Mode
+packet, it looks for a connection with itself as one end and <B>%any</B>
+as the other.
+If it cannot find one, it refuses to negotiate.  If it
+does find one, it creates a temporary connection that is a duplicate
+except with the <B>%any</B> replaced by the source IP address from the
+packet; if there was no identity specified for the peer, the new IP
+address will be used.
+<P>
+
+When <B>pluto</B> is using one of these temporary connections and
+needs to find the preshared secret or RSA private key in <I>ipsec.secrets</I>,
+and and the connection specified no identity for the peer, <B>%any</B>
+is used as its identity.  After all, the real IP address was apparently
+unknown to the configuration, so it is unreasonable to require that
+it be used in this table.
+<P>
+
+Part way into the Phase 1 (Main Mode) negotiation using one of these
+temporary connection descriptions, <B>pluto</B> will be receive an
+Identity Payload.  At this point, <B>pluto</B> checks for a more
+appropriate connection, one with an identity for the peer that matches
+the payload but which would use the same keys so-far used for
+authentication.  If it finds one, it will switch to using this better
+connection (or a temporary derived from this, if it has <B>%any</B>
+for the peer's IP address).  It may even turn out that no connection
+matches the newly discovered identity, including the current connection;
+if so, <B>pluto</B> terminates negotiation.
+<P>
+
+Unfortunately, if preshared secret authentication is being used, the
+Identity Payload is encrypted using this secret, so the secret must be
+selected by the responder without knowing this payload.  This
+limits there to being at most one preshared secret for all Road Warrior
+systems connecting to a host.  RSA Signature authentications does not
+require that the responder know how to select the initiator's public key
+until after the initiator's Identity Payload is decoded (using the
+responder's private key, so that must be preselected).
+<P>
+
+When <B>pluto</B> is responding to a Quick Mode negotiation via one of these
+temporary connection descriptions, it may well find that the subnets
+specified by the initiator don't match those in the temporary
+connection description.  If so, it will look for a connection with
+matching subnets, its own host address, a peer address of <B>%any</B>
+and matching identities.
+If it finds one, a new temporary connection is derived from this one
+and used for the Quick Mode negotiation of IPsec SAs.  If it does not
+find one, <B>pluto</B> terminates negotiation.
+<P>
+
+Be sure to specify an appropriate nexthop for the responder
+to send a message to the initiator: <B>pluto</B> has no way of guessing
+it (if forwarding isn't required, use an explicit <B>%direct</B> as the nexthop
+and the IP address of the initiator will be filled in; the obsolete
+notation <B>0.0.0.0</B> is still accepted).
+<P>
+
+<B>pluto</B> has no special provision for the initiator side.  The current
+(possibly dynamic) IP address and nexthop must be used in defining
+connections.  These must be
+properly configured each time the initiator's IP address changes.
+<B>pluto</B> has no mechanism to do this automatically.
+<P>
+
+Although we call this Road Warrior Support, it could also be used to
+support encrypted connections with anonymous initiators.  The
+responder's organization could announce the preshared secret that would be used
+with unrecognized initiators and let anyone connect.  Of course the initiator's
+identity would not be authenticated.
+<P>
+
+If any Road Warrior connections are supported, <B>pluto</B> cannot
+reject an exchange initiated by an unknown host until it has
+determined that the secret is not shared or the signature is invalid.
+This must await the
+third Main Mode message from the initiator.  If no Road Warrior
+connection is supported, the first message from an unknown source
+would be rejected.  This has implications for ease of debugging
+configurations and for denial of service attacks.
+<P>
+
+Although a Road Warrior connection must be initiated by the mobile
+side, the other side can and will rekey using the temporary connection
+it has created.  If the Road Warrior wishes to be able to disconnect,
+it is probably wise to set <B>--keyingtries</B> to 1 in the
+connection on the non-mobile side to prevent it trying to rekey the
+connection.  Unfortunately, there is no mechanism to unroute the
+connection automatically.
+<A NAME="lbAQ">&nbsp;</A>
+<H3>Debugging</H3>
+
+<P>
+
+<B>pluto</B> accepts several optional arguments, useful mostly for debugging.
+Except for <B>--interface</B>, each should appear at most once.
+<DL COMPACT>
+<DT><B>--interface</B> <I>interfacename</I><DD>
+specifies that the named real public network interface should be considered.
+The interface name specified should not be <B>ipsec</B><I>N</I>.
+If the option doesn't appear, all interfaces are considered.
+To specify several interfaces, use the option once for each.
+One use of this option is to specify which interface should be used
+when two or more share the same IP address.
+<DT><B>--ikeport</B> <I>port-number</I><DD>
+changes the UDP port that <B>pluto</B> will use
+(default, specified by IANA: 500)
+<DT><B>--ctlbase</B> <I>path</I><DD>
+basename for control files.
+<I>path</I>.ctl is the socket through which <B>whack</B> communicates with
+<B>pluto</B>.
+<I>path</I>.pid is the lockfile to prevent multiple <B>pluto</B> instances.
+The default is <I>/var/run/pluto</I>).
+<DT><B>--secretsfile</B> <I>file</I><DD>
+specifies the file for authentication secrets
+(default: <I>/etc/ipsec.secrets</I>).
+This name is subject to ``globbing'' as in <I><A HREF="sh.1.html">sh</A></I>(1),
+so every file with a matching name is processed.
+Quoting is generally needed to prevent the shell from doing the globbing.
+<DT><B>--adns</B> <I>pathname</I><DD>
+<DT><B>--lwdnsq</B> <I>pathname</I><DD>
+specifies where to find <B>pluto</B>'s helper program for asynchronous DNS lookup.
+<B>pluto</B> can be built to use one of two helper programs: <B>_pluto_adns</B>
+or <B>lwdnsq</B>.  You must use the program for which it was built.
+By default, <B>pluto</B> will look for the program in
+<B>$IPSEC_DIR</B> (if that environment variable is defined) or, failing that,
+in the same directory as <B>pluto</B>.
+<DT><B>--nofork</B><DD>
+disable ``daemon fork'' (default is to fork).  In addition, after the
+lock file and control socket are created, print the line ``Pluto
+initialized'' to standard out.
+<DT><B>--noklips</B><DD>
+don't actually implement negotiated IPsec SAs
+<DT><B>--uniqueids</B><DD>
+if this option has been selected, whenever a new ISAKMP SA is
+established, any connection with the same Peer ID but a different
+Peer IP address is unoriented (causing all its SAs to be deleted).
+This helps clean up dangling SAs when a connection is lost and
+then regained at another IP address.
+<DT><B>--stderrlog</B><DD>
+log goes to standard out {default is to use <I><A HREF="syslogd.8.html">syslogd</A></I>(8))
+</DL>
+<P>
+
+For example
+<DL COMPACT>
+<DT>pluto --secretsfile&nbsp;ipsec.secrets --ctlbase&nbsp;pluto.base --ikeport&nbsp;8500 --nofork --noklips --stderrlog<DD>
+</DL>
+<P>
+
+lets one test <B>pluto</B> without using the superuser account.
+<P>
+
+<B>pluto</B> is willing to produce a prodigious amount of debugging
+information.  To do so, it must be compiled with -DDEBUG.  There are
+several classes of debugging output, and <B>pluto</B> may be directed to
+produce a selection of them.  All lines of
+debugging output are prefixed with ``|&nbsp;'' to distinguish them from error
+messages.
+<P>
+
+When <B>pluto</B> is invoked, it may be given arguments to specify
+which classes to output.  The current options are:
+<DL COMPACT>
+<DT><B>--debug-raw</B><DD>
+show the raw bytes of messages
+<DT><B>--debug-crypt</B><DD>
+show the encryption and decryption of messages
+<DT><B>--debug-parsing</B><DD>
+show the structure of input messages
+<DT><B>--debug-emitting</B><DD>
+show the structure of output messages
+<DT><B>--debug-control</B><DD>
+show <B>pluto</B>'s decision making
+<DT><B>--debug-lifecycle</B><DD>
+[this option is temporary] log more detail of lifecycle of SAs
+<DT><B>--debug-klips</B><DD>
+show <B>pluto</B>'s interaction with <B>KLIPS</B>
+<DT><B>--debug-dns</B><DD>
+show <B>pluto</B>'s interaction with <B>DNS</B> for KEY and TXT records
+<DT><B>--debug-oppo</B><DD>
+show why <B>pluto</B> didn't find a suitable DNS TXT record to authorize opportunistic initiation
+<DT><B>--debug-all</B><DD>
+all of the above
+<DT><B>--debug-private</B><DD>
+allow debugging output with private keys.
+<DT><B>--debug-none</B><DD>
+none of the above
+</DL>
+<P>
+
+The debug form of the
+<B>whack</B> command will change the selection in a running
+<B>pluto</B>.
+If a connection name is specified, the flags are added whenever
+<B>pluto</B> has identified that it is dealing with that connection.
+Unfortunately, this is often part way into the operation being observed.
+<P>
+
+For example, to start a <B>pluto</B> with a display of the structure of input
+and output:
+<DL COMPACT>
+<DT><DD>
+pluto --debug-emitting --debug-parsing
+</DL>
+<P>
+
+To later change this <B>pluto</B> to only display raw bytes:
+<DL COMPACT>
+<DT><DD>
+whack --debug-raw
+</DL>
+<P>
+
+For testing, SSH's IKE test page is quite useful:
+<DL COMPACT>
+<DT><DD>
+<I><A HREF="http://isakmp-test.ssh.fi/">http://isakmp-test.ssh.fi/</A></I>
+</DL>
+<P>
+
+Hint: ISAKMP SAs are often kept alive by IKEs even after the IPsec SA
+is established.  This allows future IPsec SA's to be negotiated
+directly.  If one of the IKEs is restarted, the other may try to use
+the ISAKMP SA but the new IKE won't know about it.  This can lead to
+much confusion.  <B>pluto</B> is not yet smart enough to get out of such a
+mess.
+<A NAME="lbAR">&nbsp;</A>
+<H3>Pluto's Behaviour When Things Go Wrong</H3>
+
+<P>
+
+When <B>pluto</B> doesn't understand or accept a message, it just
+ignores the message.  It is not yet capable of communicating the
+problem to the other IKE daemon (in the future it might use
+Notifications to accomplish this in many cases).  It does log a diagnostic.
+<P>
+
+When <B>pluto</B> gets no response from a message, it resends the same
+message (a message will be sent at most three times).  This is
+appropriate: UDP is unreliable.
+<P>
+
+When pluto gets a message that it has already seen, there are many
+cases when it notices and discards it.  This too is appropriate for UDP.
+<P>
+
+Combine these three rules, and you can explain many apparently
+mysterious behaviours.  In a <B>pluto</B> log, retrying isn't usually the
+interesting event.  The critical thing is either earlier (<B>pluto</B>
+got a message which it didn't like and so ignored, so it was still
+awaiting an acceptable message and got impatient) or on the other
+system (<B>pluto</B> didn't send a reply because it wasn't happy with
+the previous message).
+<A NAME="lbAS">&nbsp;</A>
+<H3>Notes</H3>
+
+<P>
+
+If <B>pluto</B> is compiled without -DKLIPS, it negotiates Security
+Associations but never ask the kernel to put them in place and never
+makes routing changes.  This allows <B>pluto</B> to be tested on systems
+without <B>KLIPS</B>, but makes it rather useless.
+<P>
+
+Each IPsec SA is assigned an SPI, a 32-bit number used to refer to the SA.
+The IKE protocol lets the destination of the SA choose the SPI.
+The range 0 to 0xFF is reserved for IANA.
+<B>Pluto</B> also avoids choosing an SPI in the range 0x100 to 0xFFF,
+leaving these SPIs free for manual keying.
+Remember that the peer, if not <B>pluto</B>, may well chose
+SPIs in this range.
+<A NAME="lbAT">&nbsp;</A>
+<H3>Policies</H3>
+
+<P>
+
+This catalogue of policies may be of use when trying to configure
+<B>Pluto</B> and another IKE implementation to interoperate.
+<P>
+
+In Phase 1, only Main Mode is supported.  We are not sure that
+Aggressive Mode is secure.  For one thing, it does not support
+identity protection.  It may allow more severe Denial Of Service
+attacks.
+<P>
+
+No Informational Exchanges are supported.  These are optional and
+since their delivery is not assured, they must not matter.
+It is the case that some IKE implementations won't interoperate
+without Informational Exchanges, but we feel they are broken.
+<P>
+
+No Informational Payloads are supported.  These are optional, but
+useful.  It is of concern that these payloads are not authenticated in
+Phase 1, nor in those Phase 2 messages authenticated with <A HREF="HASH.3.html">HASH</A>(3).
+<DL COMPACT>
+<DT>*<DD>
+Diffie Hellman Groups MODP 1024 and MODP 1536 (2 and 5)
+are supported.
+Group MODP768 (1) is not supported because it is too weak.
+<DT>*<DD>
+Host authetication can be done by RSA Signatures or Pre-Shared
+Secrets.
+<DT>*<DD>
+3DES CBC (Cypher Block Chaining mode) is the only encryption
+supported, both for ISAKMP SAs and IPSEC SAs.
+<DT>*<DD>
+MD5 and SHA1 hashing are supported for packet authentication in both
+kinds of SAs.
+<DT>*<DD>
+The ESP, AH, or AH plus ESP are supported.  If, and only if, AH and
+ESP are combined, the ESP need not have its own authentication
+component.  The selection is controlled by the --encrypt and
+--authenticate flags.
+<DT>*<DD>
+Each of these may be combined with IPCOMP Deflate compression,
+but only if the potential connection specifies compression and only
+if KLIPS is configured with IPCOMP support.
+<DT>*<DD>
+The IPSEC SAs may be tunnel or transport mode, where appropriate.
+The --tunnel flag controls this when <B>pluto</B> is initiating.
+<DT>*<DD>
+When responding to an ISAKMP SA proposal, the maximum acceptable
+lifetime is eight hours.  The default is one hour.  There is no
+minimum.  The --ikelifetime flag controls this when <B>pluto</B>
+is initiating.
+<DT>*<DD>
+When responding to an IPSEC SA proposal, the maximum acceptable
+lifetime is one day.  The default is eight hours.  There is no
+minimum.  The --ipseclifetime flag controls this when <B>pluto</B>
+is initiating.
+<DT>*<DD>
+PFS is acceptable, and will be proposed if the --pfs flag was
+specified.  The DH group proposed will be the same as negotiated for
+Phase 1.
+</DL>
+<A NAME="lbAU">&nbsp;</A>
+<H2>SIGNALS</H2>
+
+<P>
+
+<B>Pluto</B> responds to <B>SIGHUP</B> by issuing a suggestion that ``<B>whack</B>
+--listen'' might have been intended.
+<P>
+
+<B>Pluto</B> exits when it recieves <B>SIGTERM</B>.
+<A NAME="lbAV">&nbsp;</A>
+<H2>EXIT STATUS</H2>
+
+<P>
+
+<B>pluto</B> normally forks a daemon process, so the exit status is
+normally a very preliminary result.
+<DL COMPACT>
+<DT>0<DD>
+means that all is OK so far.
+<DT>1<DD>
+means that something was wrong.
+<DT>10<DD>
+means that the lock file already exists.
+</DL>
+<P>
+
+If <B>whack</B> detects a problem, it will return an exit status of 1.
+If it received progress messages from <B>pluto</B>, it returns as status
+the value of the numeric prefix from the last such message
+that was not a message sent to syslog or a comment
+(but the prefix for success is treated as 0).
+Otherwise, the exit status is 0.
+<A NAME="lbAW">&nbsp;</A>
+<H2>FILES</H2>
+
+<I>/var/run/pluto.pid</I>
+<BR>
+
+<I>/var/run/pluto.ctl</I>
+<BR>
+
+<I>/etc/ipsec.secrets</I>
+<BR>
+
+<I>$IPSEC_LIBDIR/_pluto_adns</I>
+<BR>
+
+<I>$IPSEC_EXECDIR/lwdnsq</I>
+<BR>
+
+<I>/dev/urandom</I>
+<A NAME="lbAX">&nbsp;</A>
+<H2>ENVIRONMENT</H2>
+
+<I>IPSEC_LIBDIR</I>
+<BR>
+
+<I>IPSEC_EXECDIR</I>
+<BR>
+
+<I>IPSECmyid</I>
+<A NAME="lbAY">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<P>
+
+The rest of the FreeS/WAN distribution, in particular <I><A HREF="ipsec.8.html">ipsec</A></I>(8).
+<P>
+
+<I><A HREF="ipsec_auto.8.html">ipsec_auto</A></I>(8) is designed to make using <B>pluto</B> more pleasant.
+Use it!
+<P>
+
+<I><A HREF="ipsec.secrets.5.html">ipsec.secrets</A></I>(5)
+
+describes the format of the secrets file.
+<P>
+
+<I><A HREF="ipsec_atoaddr.3.html">ipsec_atoaddr</A></I>(3), part of the FreeS/WAN distribution, describes the
+forms that IP addresses may take.
+<I><A HREF="ipsec_atosubnet.3.html">ipsec_atosubnet</A></I>(3), part of the FreeS/WAN distribution, describes the
+forms that subnet specifications.
+<P>
+
+For more information on IPsec, the mailing list, and the relevant
+documents, see:
+<DL COMPACT>
+<DT><DD>
+
+<I><A HREF="http://www.ietf.cnri.reston.va.us/html.charters/ipsec-charter.html">http://www.ietf.cnri.reston.va.us/html.charters/ipsec-charter.html</A></I>
+
+</DL>
+<P>
+
+At the time of writing, the most relevant IETF RFCs are:
+<DL COMPACT>
+<DT><DD>
+RFC2409 The Internet Key Exchange (IKE)
+<DT><DD>
+RFC2408 Internet Security Association and Key Management Protocol (ISAKMP)
+<DT><DD>
+RFC2407 The Internet IP Security Domain of Interpretation for ISAKMP
+</DL>
+<P>
+
+The FreeS/WAN web site &lt;<A HREF="htp://www.freeswan.org">htp://www.freeswan.org</A>&gt;
+and the mailing lists described there.
+<A NAME="lbAZ">&nbsp;</A>
+<H2>HISTORY</H2>
+
+This code is released under the GPL terms.
+See the accompanying file COPYING-2.0 for more details.
+The GPL does NOT apply to those pieces of code written by others
+which are included in this distribution, except as noted by the
+individual authors.
+<P>
+
+This software was originally written
+for the FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org">http://www.freeswan.org</A>&gt;
+by Angelos D. Keromytis
+(<A HREF="mailto:angelos@dsl.cis.upenn.edu">angelos@dsl.cis.upenn.edu</A>), in May/June 1997, in Athens, Greece.
+Thanks go to John Ioannidis for his help.
+<P>
+
+It is currently (2000)
+being developed and maintained by D. Hugh Redelmeier
+(<A HREF="mailto:hugh@mimosa.com">hugh@mimosa.com</A>), in Canada.  The regulations of Greece and Canada
+allow us to make the code freely redistributable.
+<P>
+
+Kai Martius (<A HREF="mailto:admin@imib.med.tu-dresden.de">admin@imib.med.tu-dresden.de</A>) contributed the initial
+version of the code supporting PFS.
+<P>
+
+Richard Guy Briggs &lt;<A HREF="mailto:rgb@conscoop.ottawa.on.ca">rgb@conscoop.ottawa.on.ca</A>&gt; and Peter Onion
+&lt;<A HREF="mailto:ponion@srd.bt.co.uk">ponion@srd.bt.co.uk</A>&gt; added the PFKEY2 support.
+<P>
+
+We gratefully acknowledge that we use parts of Eric Young's <I>libdes</I>
+package; see <I>../libdes/COPYRIGHT</I>.
+<A NAME="lbBA">&nbsp;</A>
+<H2>BUGS</H2>
+
+<B>pluto</B>
+
+is a work-in-progress.  It currently has many limitations.
+For example, it ignores notification messages that it receives, and
+it generates only Delete Notifications and those only for IPSEC SAs.
+<P>
+
+<B>pluto</B> does not support the Commit Flag.
+The Commit Flag is a bad feature of the IKE protocol.
+It isn't protected -- neither encrypted nor authenticated.
+A man in the middle could turn it on, leading to DoS.
+We just ignore it, with a warning.
+This should let us interoperate with
+implementations that insist on it, with minor damage.
+<P>
+
+<B>pluto</B> does not check that the SA returned by the Responder
+is actually one that was proposed.  It only checks that the SA is
+acceptable.  The difference is not large, but can show up in attributes
+such as SA lifetime.
+<P>
+
+There is no good way for a connection to be automatically terminated.
+This is a problem for Road Warrior and Opportunistic connections.
+The <B>--dontrekey</B> option does prevent the SAs from
+being rekeyed on expiry.
+Additonally, if a Road Warrior connection has a client subnet with a fixed IP
+address, a negotiation with that subnet will cause any other
+connection instantiations with that same subnet to be unoriented
+(deleted, in effect).
+See also the --uniqueids option for an extension of this.
+<P>
+
+When <B>pluto</B> sends a message to a peer that has disappeared,
+<B>pluto</B> receives incomplete information from the kernel, so it
+logs the unsatisfactory message ``some IKE message we sent has been
+rejected with ECONNREFUSED (kernel supplied no details)''.  John
+Denker suggests that this command is useful for tracking down the
+source of these problems:
+<BR>
+
+<TT>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TT>tcpdump -i eth0 icmp[0] != 8 and icmp[0] != 0<BR>
+<BR>
+
+Substitute your public interface for eth0 if it is different.
+<P>
+
+The word ``authenticate'' is used for two different features.  We must
+authenticate each IKE peer to the other.  This is an important task of
+Phase 1.  Each packet must be authenticated, both in IKE and in IPsec,
+and the method for IPsec is negotiated as an AH SA or part of an ESP SA.
+Unfortunately, the protocol has no mechanism for authenticating the Phase 2
+identities.
+<P>
+
+Bugs should be reported to the &lt;<A HREF="mailto:users@lists.freeswan.org">users@lists.freeswan.org</A>&gt; mailing list.
+Caution: we cannot accept
+actual code from US residents, or even US citizens living outside the
+US, because that would bring FreeS/WAN under US export law.  Some
+other countries cause similar problems.  In general, we would prefer
+that you send detailed problem reports rather than code:  we want
+FreeS/WAN to be unquestionably freely exportable, which means being
+very careful about where the code comes from, and for a small bug fix,
+that is often more time-consuming than just reinventing the fix
+ourselves.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DL>
+<DT><A HREF="#lbAE">IKE's Job</A><DD>
+<DT><A HREF="#lbAF">Pluto</A><DD>
+<DT><A HREF="#lbAG">Before Running Pluto</A><DD>
+<DT><A HREF="#lbAH">Setting up <B>KLIPS</B> for <B>pluto</B></A><DD>
+<DT><A HREF="#lbAI">ipsec.secrets file</A><DD>
+<DT><A HREF="#lbAJ">Running Pluto</A><DD>
+<DT><A HREF="#lbAK">Pluto's Internal State</A><DD>
+<DT><A HREF="#lbAL">Using Whack</A><DD>
+<DT><A HREF="#lbAM">Examples</A><DD>
+<DT><A HREF="#lbAN">The updown command</A><DD>
+<DT><A HREF="#lbAO">Rekeying</A><DD>
+<DT><A HREF="#lbAP">Selecting a Connection When Responding: Road Warrior Support</A><DD>
+<DT><A HREF="#lbAQ">Debugging</A><DD>
+<DT><A HREF="#lbAR">Pluto's Behaviour When Things Go Wrong</A><DD>
+<DT><A HREF="#lbAS">Notes</A><DD>
+<DT><A HREF="#lbAT">Policies</A><DD>
+</DL>
+<DT><A HREF="#lbAU">SIGNALS</A><DD>
+<DT><A HREF="#lbAV">EXIT STATUS</A><DD>
+<DT><A HREF="#lbAW">FILES</A><DD>
+<DT><A HREF="#lbAX">ENVIRONMENT</A><DD>
+<DT><A HREF="#lbAY">SEE ALSO</A><DD>
+<DT><A HREF="#lbAZ">HISTORY</A><DD>
+<DT><A HREF="#lbBA">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_portof.3.html b/doc/manpage.d/ipsec_portof.3.html
new file mode 100644
index 000000000..3965ca62d
--- /dev/null
+++ b/doc/manpage.d/ipsec_portof.3.html
@@ -0,0 +1,143 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_PORTOF</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_PORTOF</H1>
+Section: C Library Functions (3)<BR>Updated: 8 Sept 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec portof - get port field of an ip_address
+<BR>
+
+ipsec setportof - set port field of an ip_address
+<BR>
+
+ipsec sockaddrof - get pointer to internal sockaddr of an ip_address
+<BR>
+
+ipsec sockaddrlenof - get length of internal sockaddr of an ip_address
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>int portof(const ip_address *src);</B>
+
+<BR>
+
+<B>void setportof(int port, ip_address *dst);</B>
+
+<BR>
+
+<B>struct sockaddr *sockaddrof(ip_address *src);</B>
+
+<BR>
+
+<B>size_t sockaddrlenof(const ip_address *src);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+internal type
+<I>ip_address</I>
+
+contains one of the
+<I>sockaddr</I>
+
+types internally.
+<I>Reliance on this feature is discouraged</I>,
+but it may occasionally be necessary.
+These functions provide low-level tools for this purpose.
+<P>
+
+<I>Portof</I>
+
+and
+<I>setportof</I>
+
+respectively read and write the port-number field of the internal
+<I>sockaddr</I>.
+
+The values are in network byte order.
+<P>
+
+<I>Sockaddrof</I>
+
+returns a pointer to the internal
+<I>sockaddr</I>,
+
+for passing to other functions.
+<P>
+
+<I>Sockaddrlenof</I>
+
+reports the size of the internal
+<I>sockaddr</I>,
+
+for use in storage allocation.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_initaddr.3.html">ipsec_initaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+<I>Portof</I>
+
+returns
+<B>-1</B>,
+
+<I>sockaddrof</I>
+
+returns
+<B>NULL</B>,
+
+and
+<I>sockaddrlenof</I>
+
+returns
+<B>0</B>
+
+if an unknown address family is found within the
+<I>ip_address</I>.
+
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+These functions all depend on low-level details of the
+<I>ip_address</I>
+
+type, which are in principle subject to change.
+Avoid using them unless really necessary.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_prng.3.html b/doc/manpage.d/ipsec_prng.3.html
new file mode 100644
index 000000000..27763a2bb
--- /dev/null
+++ b/doc/manpage.d/ipsec_prng.3.html
@@ -0,0 +1,204 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_PRNG</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_PRNG</H1>
+Section: C Library Functions (3)<BR>Updated: 1 April 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec prng_init - initialize IPsec pseudorandom-number generator
+<BR>
+
+ipsec prng_bytes - get bytes from IPsec pseudorandom-number generator
+<BR>
+
+ipsec prng_final - close down IPsec pseudorandom-number generator
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>void prng_init(struct prng *prng,</B>
+
+<BR>
+&nbsp;
+<B>const unsigned char *key, size_t keylen);</B>
+
+<BR>
+
+<B>void prng_bytes(struct prng *prng, char *dst,</B>
+
+<BR>
+&nbsp;
+<B>size_t dstlen);</B>
+
+<BR>
+
+<B>unsigned long prng_count(struct prng *prng);</B>
+
+<BR>
+
+<B>void prng_final(struct prng *prng);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Prng_init</I>
+
+initializes a crypto-quality pseudo-random-number generator from a key;
+<I>prng_bytes</I>
+
+obtains pseudo-random bytes from it;
+<I>prng_count</I>
+
+reports the number of bytes extracted from it to date;
+<I>prng_final</I>
+
+closes it down.
+It is the user's responsibility to initialize a PRNG before using it,
+and not to use it again after it is closed down.
+<P>
+
+<I>Prng_init</I>
+
+initializes,
+or re-initializes,
+the specified
+<I>prng</I>
+
+from the
+<I>key</I>,
+
+whose length is given by
+<I>keylen</I>.
+
+The user must allocate the
+<B>struct prng</B>
+
+pointed to by
+<I>prng</I>.
+
+There is no particular constraint on the length of the key,
+although a key longer than 256 bytes is unnecessary because
+only the first 256 would be used.
+Initialization requires on the order of 3000 integer operations,
+independent of key length.
+<P>
+
+<I>Prng_bytes</I>
+
+obtains
+<I>dstlen</I>
+
+pseudo-random bytes from the PRNG and puts them in
+<I>buf</I>.
+
+This is quite fast,
+on the order of 10 integer operations per byte.
+<P>
+
+<I>Prng_count</I>
+
+reports the number of bytes obtained from the PRNG
+since it was (last) initialized.
+<P>
+
+<I>Prng_final</I>
+
+closes down a PRNG by
+zeroing its internal memory,
+obliterating all trace of the state used to generate its previous output.
+This requires on the order of 250 integer operations.
+<P>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file supplies the definition of the
+<B>prng</B>
+
+structure.
+Examination of its innards is discouraged, as they may change.
+<P>
+
+The PRNG algorithm
+used by these functions is currently identical to that of RC4(TM).
+This algorithm is cryptographically strong,
+sufficiently unpredictable that even a hostile observer will
+have difficulty determining the next byte of output from past history,
+provided it is initialized from a reasonably large key composed of
+highly random bytes (see
+<I><A HREF="random.4.html">random</A></I>(4)).
+
+The usual run of software pseudo-random-number generators
+(e.g.
+<I><A HREF="random.3.html">random</A></I>(3))
+
+are
+<I>not</I>
+
+cryptographically strong.
+<P>
+
+The well-known attacks against RC4(TM),
+e.g. as found in 802.11b's WEP encryption system,
+apply only if multiple PRNGs are initialized with closely-related keys
+(e.g., using a counter appended to a base key).
+If such keys are used, the first few hundred pseudo-random bytes
+from each PRNG should be discarded,
+to give the PRNGs a chance to randomize their innards properly.
+No useful attacks are known if the key is well randomized to begin with.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="random.3.html">random</A>(3), <A HREF="random.4.html">random</A>(4)
+<BR>
+
+Bruce Schneier,
+<I>Applied Cryptography</I>, 2nd ed., 1996, ISBN 0-471-11709-9,
+pp. 397-8.
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAG">&nbsp;</A>
+<H2>BUGS</H2>
+
+If an attempt is made to obtain more than 4e9 bytes
+between initializations,
+the PRNG will continue to work but
+<I>prng_count</I>'s
+
+output will stick at
+<B>4000000000</B>.
+
+Fixing this would require a longer integer type and does
+not seem worth the trouble,
+since you should probably re-initialize before then anyway...
+<P>
+
+``RC4'' is a trademark of RSA Data Security, Inc.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+<DT><A HREF="#lbAG">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_prng_bytes.3.html b/doc/manpage.d/ipsec_prng_bytes.3.html
new file mode 100644
index 000000000..27763a2bb
--- /dev/null
+++ b/doc/manpage.d/ipsec_prng_bytes.3.html
@@ -0,0 +1,204 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_PRNG</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_PRNG</H1>
+Section: C Library Functions (3)<BR>Updated: 1 April 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec prng_init - initialize IPsec pseudorandom-number generator
+<BR>
+
+ipsec prng_bytes - get bytes from IPsec pseudorandom-number generator
+<BR>
+
+ipsec prng_final - close down IPsec pseudorandom-number generator
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>void prng_init(struct prng *prng,</B>
+
+<BR>
+&nbsp;
+<B>const unsigned char *key, size_t keylen);</B>
+
+<BR>
+
+<B>void prng_bytes(struct prng *prng, char *dst,</B>
+
+<BR>
+&nbsp;
+<B>size_t dstlen);</B>
+
+<BR>
+
+<B>unsigned long prng_count(struct prng *prng);</B>
+
+<BR>
+
+<B>void prng_final(struct prng *prng);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Prng_init</I>
+
+initializes a crypto-quality pseudo-random-number generator from a key;
+<I>prng_bytes</I>
+
+obtains pseudo-random bytes from it;
+<I>prng_count</I>
+
+reports the number of bytes extracted from it to date;
+<I>prng_final</I>
+
+closes it down.
+It is the user's responsibility to initialize a PRNG before using it,
+and not to use it again after it is closed down.
+<P>
+
+<I>Prng_init</I>
+
+initializes,
+or re-initializes,
+the specified
+<I>prng</I>
+
+from the
+<I>key</I>,
+
+whose length is given by
+<I>keylen</I>.
+
+The user must allocate the
+<B>struct prng</B>
+
+pointed to by
+<I>prng</I>.
+
+There is no particular constraint on the length of the key,
+although a key longer than 256 bytes is unnecessary because
+only the first 256 would be used.
+Initialization requires on the order of 3000 integer operations,
+independent of key length.
+<P>
+
+<I>Prng_bytes</I>
+
+obtains
+<I>dstlen</I>
+
+pseudo-random bytes from the PRNG and puts them in
+<I>buf</I>.
+
+This is quite fast,
+on the order of 10 integer operations per byte.
+<P>
+
+<I>Prng_count</I>
+
+reports the number of bytes obtained from the PRNG
+since it was (last) initialized.
+<P>
+
+<I>Prng_final</I>
+
+closes down a PRNG by
+zeroing its internal memory,
+obliterating all trace of the state used to generate its previous output.
+This requires on the order of 250 integer operations.
+<P>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file supplies the definition of the
+<B>prng</B>
+
+structure.
+Examination of its innards is discouraged, as they may change.
+<P>
+
+The PRNG algorithm
+used by these functions is currently identical to that of RC4(TM).
+This algorithm is cryptographically strong,
+sufficiently unpredictable that even a hostile observer will
+have difficulty determining the next byte of output from past history,
+provided it is initialized from a reasonably large key composed of
+highly random bytes (see
+<I><A HREF="random.4.html">random</A></I>(4)).
+
+The usual run of software pseudo-random-number generators
+(e.g.
+<I><A HREF="random.3.html">random</A></I>(3))
+
+are
+<I>not</I>
+
+cryptographically strong.
+<P>
+
+The well-known attacks against RC4(TM),
+e.g. as found in 802.11b's WEP encryption system,
+apply only if multiple PRNGs are initialized with closely-related keys
+(e.g., using a counter appended to a base key).
+If such keys are used, the first few hundred pseudo-random bytes
+from each PRNG should be discarded,
+to give the PRNGs a chance to randomize their innards properly.
+No useful attacks are known if the key is well randomized to begin with.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="random.3.html">random</A>(3), <A HREF="random.4.html">random</A>(4)
+<BR>
+
+Bruce Schneier,
+<I>Applied Cryptography</I>, 2nd ed., 1996, ISBN 0-471-11709-9,
+pp. 397-8.
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAG">&nbsp;</A>
+<H2>BUGS</H2>
+
+If an attempt is made to obtain more than 4e9 bytes
+between initializations,
+the PRNG will continue to work but
+<I>prng_count</I>'s
+
+output will stick at
+<B>4000000000</B>.
+
+Fixing this would require a longer integer type and does
+not seem worth the trouble,
+since you should probably re-initialize before then anyway...
+<P>
+
+``RC4'' is a trademark of RSA Data Security, Inc.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+<DT><A HREF="#lbAG">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_prng_final.3.html b/doc/manpage.d/ipsec_prng_final.3.html
new file mode 100644
index 000000000..27763a2bb
--- /dev/null
+++ b/doc/manpage.d/ipsec_prng_final.3.html
@@ -0,0 +1,204 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_PRNG</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_PRNG</H1>
+Section: C Library Functions (3)<BR>Updated: 1 April 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec prng_init - initialize IPsec pseudorandom-number generator
+<BR>
+
+ipsec prng_bytes - get bytes from IPsec pseudorandom-number generator
+<BR>
+
+ipsec prng_final - close down IPsec pseudorandom-number generator
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>void prng_init(struct prng *prng,</B>
+
+<BR>
+&nbsp;
+<B>const unsigned char *key, size_t keylen);</B>
+
+<BR>
+
+<B>void prng_bytes(struct prng *prng, char *dst,</B>
+
+<BR>
+&nbsp;
+<B>size_t dstlen);</B>
+
+<BR>
+
+<B>unsigned long prng_count(struct prng *prng);</B>
+
+<BR>
+
+<B>void prng_final(struct prng *prng);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Prng_init</I>
+
+initializes a crypto-quality pseudo-random-number generator from a key;
+<I>prng_bytes</I>
+
+obtains pseudo-random bytes from it;
+<I>prng_count</I>
+
+reports the number of bytes extracted from it to date;
+<I>prng_final</I>
+
+closes it down.
+It is the user's responsibility to initialize a PRNG before using it,
+and not to use it again after it is closed down.
+<P>
+
+<I>Prng_init</I>
+
+initializes,
+or re-initializes,
+the specified
+<I>prng</I>
+
+from the
+<I>key</I>,
+
+whose length is given by
+<I>keylen</I>.
+
+The user must allocate the
+<B>struct prng</B>
+
+pointed to by
+<I>prng</I>.
+
+There is no particular constraint on the length of the key,
+although a key longer than 256 bytes is unnecessary because
+only the first 256 would be used.
+Initialization requires on the order of 3000 integer operations,
+independent of key length.
+<P>
+
+<I>Prng_bytes</I>
+
+obtains
+<I>dstlen</I>
+
+pseudo-random bytes from the PRNG and puts them in
+<I>buf</I>.
+
+This is quite fast,
+on the order of 10 integer operations per byte.
+<P>
+
+<I>Prng_count</I>
+
+reports the number of bytes obtained from the PRNG
+since it was (last) initialized.
+<P>
+
+<I>Prng_final</I>
+
+closes down a PRNG by
+zeroing its internal memory,
+obliterating all trace of the state used to generate its previous output.
+This requires on the order of 250 integer operations.
+<P>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file supplies the definition of the
+<B>prng</B>
+
+structure.
+Examination of its innards is discouraged, as they may change.
+<P>
+
+The PRNG algorithm
+used by these functions is currently identical to that of RC4(TM).
+This algorithm is cryptographically strong,
+sufficiently unpredictable that even a hostile observer will
+have difficulty determining the next byte of output from past history,
+provided it is initialized from a reasonably large key composed of
+highly random bytes (see
+<I><A HREF="random.4.html">random</A></I>(4)).
+
+The usual run of software pseudo-random-number generators
+(e.g.
+<I><A HREF="random.3.html">random</A></I>(3))
+
+are
+<I>not</I>
+
+cryptographically strong.
+<P>
+
+The well-known attacks against RC4(TM),
+e.g. as found in 802.11b's WEP encryption system,
+apply only if multiple PRNGs are initialized with closely-related keys
+(e.g., using a counter appended to a base key).
+If such keys are used, the first few hundred pseudo-random bytes
+from each PRNG should be discarded,
+to give the PRNGs a chance to randomize their innards properly.
+No useful attacks are known if the key is well randomized to begin with.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="random.3.html">random</A>(3), <A HREF="random.4.html">random</A>(4)
+<BR>
+
+Bruce Schneier,
+<I>Applied Cryptography</I>, 2nd ed., 1996, ISBN 0-471-11709-9,
+pp. 397-8.
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAG">&nbsp;</A>
+<H2>BUGS</H2>
+
+If an attempt is made to obtain more than 4e9 bytes
+between initializations,
+the PRNG will continue to work but
+<I>prng_count</I>'s
+
+output will stick at
+<B>4000000000</B>.
+
+Fixing this would require a longer integer type and does
+not seem worth the trouble,
+since you should probably re-initialize before then anyway...
+<P>
+
+``RC4'' is a trademark of RSA Data Security, Inc.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+<DT><A HREF="#lbAG">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_prng_init.3.html b/doc/manpage.d/ipsec_prng_init.3.html
new file mode 100644
index 000000000..27763a2bb
--- /dev/null
+++ b/doc/manpage.d/ipsec_prng_init.3.html
@@ -0,0 +1,204 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_PRNG</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_PRNG</H1>
+Section: C Library Functions (3)<BR>Updated: 1 April 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec prng_init - initialize IPsec pseudorandom-number generator
+<BR>
+
+ipsec prng_bytes - get bytes from IPsec pseudorandom-number generator
+<BR>
+
+ipsec prng_final - close down IPsec pseudorandom-number generator
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>void prng_init(struct prng *prng,</B>
+
+<BR>
+&nbsp;
+<B>const unsigned char *key, size_t keylen);</B>
+
+<BR>
+
+<B>void prng_bytes(struct prng *prng, char *dst,</B>
+
+<BR>
+&nbsp;
+<B>size_t dstlen);</B>
+
+<BR>
+
+<B>unsigned long prng_count(struct prng *prng);</B>
+
+<BR>
+
+<B>void prng_final(struct prng *prng);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Prng_init</I>
+
+initializes a crypto-quality pseudo-random-number generator from a key;
+<I>prng_bytes</I>
+
+obtains pseudo-random bytes from it;
+<I>prng_count</I>
+
+reports the number of bytes extracted from it to date;
+<I>prng_final</I>
+
+closes it down.
+It is the user's responsibility to initialize a PRNG before using it,
+and not to use it again after it is closed down.
+<P>
+
+<I>Prng_init</I>
+
+initializes,
+or re-initializes,
+the specified
+<I>prng</I>
+
+from the
+<I>key</I>,
+
+whose length is given by
+<I>keylen</I>.
+
+The user must allocate the
+<B>struct prng</B>
+
+pointed to by
+<I>prng</I>.
+
+There is no particular constraint on the length of the key,
+although a key longer than 256 bytes is unnecessary because
+only the first 256 would be used.
+Initialization requires on the order of 3000 integer operations,
+independent of key length.
+<P>
+
+<I>Prng_bytes</I>
+
+obtains
+<I>dstlen</I>
+
+pseudo-random bytes from the PRNG and puts them in
+<I>buf</I>.
+
+This is quite fast,
+on the order of 10 integer operations per byte.
+<P>
+
+<I>Prng_count</I>
+
+reports the number of bytes obtained from the PRNG
+since it was (last) initialized.
+<P>
+
+<I>Prng_final</I>
+
+closes down a PRNG by
+zeroing its internal memory,
+obliterating all trace of the state used to generate its previous output.
+This requires on the order of 250 integer operations.
+<P>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file supplies the definition of the
+<B>prng</B>
+
+structure.
+Examination of its innards is discouraged, as they may change.
+<P>
+
+The PRNG algorithm
+used by these functions is currently identical to that of RC4(TM).
+This algorithm is cryptographically strong,
+sufficiently unpredictable that even a hostile observer will
+have difficulty determining the next byte of output from past history,
+provided it is initialized from a reasonably large key composed of
+highly random bytes (see
+<I><A HREF="random.4.html">random</A></I>(4)).
+
+The usual run of software pseudo-random-number generators
+(e.g.
+<I><A HREF="random.3.html">random</A></I>(3))
+
+are
+<I>not</I>
+
+cryptographically strong.
+<P>
+
+The well-known attacks against RC4(TM),
+e.g. as found in 802.11b's WEP encryption system,
+apply only if multiple PRNGs are initialized with closely-related keys
+(e.g., using a counter appended to a base key).
+If such keys are used, the first few hundred pseudo-random bytes
+from each PRNG should be discarded,
+to give the PRNGs a chance to randomize their innards properly.
+No useful attacks are known if the key is well randomized to begin with.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="random.3.html">random</A>(3), <A HREF="random.4.html">random</A>(4)
+<BR>
+
+Bruce Schneier,
+<I>Applied Cryptography</I>, 2nd ed., 1996, ISBN 0-471-11709-9,
+pp. 397-8.
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAG">&nbsp;</A>
+<H2>BUGS</H2>
+
+If an attempt is made to obtain more than 4e9 bytes
+between initializations,
+the PRNG will continue to work but
+<I>prng_count</I>'s
+
+output will stick at
+<B>4000000000</B>.
+
+Fixing this would require a longer integer type and does
+not seem worth the trouble,
+since you should probably re-initialize before then anyway...
+<P>
+
+``RC4'' is a trademark of RSA Data Security, Inc.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+<DT><A HREF="#lbAG">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_ranbits.8.html b/doc/manpage.d/ipsec_ranbits.8.html
new file mode 100644
index 000000000..036b2a351
--- /dev/null
+++ b/doc/manpage.d/ipsec_ranbits.8.html
@@ -0,0 +1,147 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_RANBITS</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_RANBITS</H1>
+Section: Maintenance Commands (8)<BR>Updated: 22 Aug 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec ranbits - generate random bits in ASCII form
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>ranbits</B>
+
+[
+<B>--quick</B>
+
+] [
+<B>--continuous</B>
+
+] [
+<B>--bytes</B>
+
+] nbits
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Ranbits</I>
+
+obtains
+<I>nbits</I>
+
+(rounded up to the nearest byte)
+high-quality random bits from
+<I><A HREF="random.4.html">random</A></I>(4),
+
+and emits them on standard output as an ASCII string.
+The default output format is
+<I><A HREF="datatot.3.html">datatot</A></I>(3)
+
+<B>h</B>
+
+format:
+lowercase hexadecimal with a
+<B>0x</B>
+
+prefix and an underscore every 32 bits.
+<P>
+
+The
+<B>--quick</B>
+
+option produces quick-and-dirty random bits:
+instead of using the high-quality random bits from
+<I>/dev/random</I>,
+
+which may take some time to supply the necessary bits if
+<I>nbits</I>
+
+is large,
+<I>ranbits</I>
+
+uses
+<I>/dev/urandom</I>,
+
+which yields prompt results but lower-quality randomness.
+<P>
+
+The
+<B>--continuous</B>
+
+option uses
+<I><A HREF="datatot.3.html">datatot</A></I>(3)
+
+<B>x</B>
+
+output format, like
+<B>h</B>
+
+but without the underscores.
+<P>
+
+The
+<B>--bytes</B>
+
+option causes
+<I>nbits</I>
+
+to be interpreted as a byte count rather than a bit count.
+<A NAME="lbAE">&nbsp;</A>
+<H2>FILES</H2>
+
+/dev/random, /dev/urandom
+<A NAME="lbAF">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec_datatot.3.html">ipsec_datatot</A>(3), <A HREF="random.4.html">random</A>(4)
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org">http://www.freeswan.org</A>&gt;
+by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+There is an internal limit on
+<I>nbits</I>,
+
+currently 20000.
+<P>
+
+Without
+<B>--quick</B>,
+
+<I>ranbits</I>'s
+
+run time is difficult to predict.
+A request for a large number of bits,
+at a time when the system's entropy pool is low on randomness,
+may take quite a while to satisfy.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">FILES</A><DD>
+<DT><A HREF="#lbAF">SEE ALSO</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_rangetoa.3.html b/doc/manpage.d/ipsec_rangetoa.3.html
new file mode 100644
index 000000000..3bacd5943
--- /dev/null
+++ b/doc/manpage.d/ipsec_rangetoa.3.html
@@ -0,0 +1,294 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ATOASR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ATOASR</H1>
+Section: C Library Functions (3)<BR>Updated: 11 June 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec atoasr - convert ASCII to Internet address, subnet, or range
+<BR>
+
+ipsec rangetoa - convert Internet address range to ASCII
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *atoasr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>char *type, struct in_addr *addrs);</B>
+
+<BR>
+
+<B>size_t rangetoa(struct in_addr *addrs, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions are obsolete;
+there is no current equivalent,
+because so far they have not proved useful.
+<P>
+
+<I>Atoasr</I>
+
+converts an ASCII address, subnet, or address range
+into a suitable combination of binary addresses
+(in network byte order).
+<I>Rangetoa</I>
+
+converts an address range back into ASCII,
+using dotted-decimal form for the addresses
+(the other reverse conversions are handled by
+<I><A HREF="ipsec_addrtoa.3.html">ipsec_addrtoa</A></I>(3)
+
+and
+<I><A HREF="ipsec_subnettoa.3.html">ipsec_subnettoa</A></I>(3)).
+
+<P>
+
+A single address can be any form acceptable to
+<I><A HREF="ipsec_atoaddr.3.html">ipsec_atoaddr</A></I>(3):
+
+dotted decimal, DNS name, or hexadecimal number.
+A subnet
+specification uses the form <I>network</I><B>/</B><I>mask</I>
+interpreted by
+<I><A HREF="ipsec_atosubnet.3.html">ipsec_atosubnet</A></I>(3).
+
+<P>
+
+An address range is two
+<I><A HREF="ipsec_atoaddr.3.html">ipsec_atoaddr</A></I>(3)
+
+addresses separated by a
+<B>...</B>
+
+delimiter.
+If there are four dots rather than three, the first is taken as
+part of the begin address,
+e.g. for a complete DNS name which ends with
+<B>.</B>
+
+to suppress completion attempts.
+The begin address of a range must be
+less than or equal to the end address.
+<P>
+
+The
+<I>srclen</I>
+
+parameter of
+<I>atoasr</I>
+
+specifies the length of the ASCII string pointed to by
+<I>src</I>;
+
+it is an error for there to be anything else
+(e.g., a terminating NUL) within that length.
+As a convenience for cases where an entire NUL-terminated string is
+to be converted,
+a
+<I>srclen</I>
+
+value of
+<B>0</B>
+
+is taken to mean
+<B>strlen(src)</B>.
+
+<P>
+
+The
+<I>type</I>
+
+parameter of
+<I>atoasr</I>
+
+must point to a
+<B>char</B>
+
+variable used to record which form was found.
+The
+<I>addrs</I>
+
+parameter must point to a two-element array of
+<B>struct in_addr</B>
+
+which receives the results.
+The values stored into
+<B>*type</B>,
+
+and the corresponding values in the array, are:
+<P>
+
+
+
+<TT>&nbsp;&nbsp;&nbsp;</TT>*typeaddrs[0]addrs[1]<BR>
+<P>
+address<B>'a'</B>address-<BR>
+<BR>
+
+subnet<TT>&nbsp;</TT><B>'s'</B>networkmask<BR>
+<BR>
+
+range<TT>&nbsp;&nbsp;</TT><B>'r'</B>beginend<BR>
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of
+<I>rangetoa</I>
+
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+The
+<I>freeswan.h</I>
+
+header file defines a constant,
+<B>RANGETOA_BUF</B>,
+
+which is the size of a buffer just large enough for worst-case results.
+<P>
+
+The
+<I>format</I>
+
+parameter of
+<I>rangetoa</I>
+
+specifies what format is to be used for the conversion.
+The value
+<B>0</B>
+
+(not the ASCII character
+<B>'0'</B>,
+
+but a zero value)
+specifies a reasonable default,
+and is in fact the only format currently available.
+This parameter is a hedge against future needs.
+<P>
+
+<I>Atoasr</I>
+
+returns NULL for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<I>Rangetoa</I>
+
+returns
+<B>0</B>
+
+for a failure, and otherwise
+always returns the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL;
+it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec_atoaddr.3.html">ipsec_atoaddr</A>(3), <A HREF="ipsec_atosubnet.3.html">ipsec_atosubnet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>atoasr</I>
+
+are:
+empty input;
+error in
+<I><A HREF="ipsec_atoaddr.3.html">ipsec_atoaddr</A></I>(3)
+
+or
+<I><A HREF="ipsec_atosubnet.3.html">ipsec_atosubnet</A></I>(3)
+
+during conversion;
+begin address of range exceeds end address.
+<P>
+
+Fatal errors in
+<I>rangetoa</I>
+
+are:
+unknown format.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+The restriction of error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The error-reporting convention lends itself
+to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = atoasr( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_rangetosubnet.3.html b/doc/manpage.d/ipsec_rangetosubnet.3.html
new file mode 100644
index 000000000..9e03244ea
--- /dev/null
+++ b/doc/manpage.d/ipsec_rangetosubnet.3.html
@@ -0,0 +1,116 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_RANGETOSUBNET</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_RANGETOSUBNET</H1>
+Section: C Library Functions (3)<BR>Updated: 8 Sept 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec rangetosubnet - convert address range to subnet
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *rangetosubnet(const ip_address *start,</B>
+
+<BR>
+&nbsp;
+<B>const ip_address *stop, ip_subnet *dst);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Rangetosubnet</I>
+
+accepts two IP addresses which define an address range,
+from
+<I>start</I>
+
+to
+<I>stop</I>
+
+inclusive,
+and converts this to a subnet if possible.
+The addresses must both be IPv4 or both be IPv6,
+and the address family of the resulting subnet is the same.
+<P>
+
+<I>Rangetosubnet</I>
+
+returns NULL for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec_initsubnet.3.html">ipsec_initsubnet</A>(3), <A HREF="ipsec_ttosubnet.3.html">ipsec_ttosubnet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>rangetosubnet</I>
+
+are:
+mixed address families;
+unknown address family;
+<I>start</I>
+
+and
+<I>stop</I>
+
+do not define a subnet.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+The restriction of error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The error-reporting convention lends itself
+to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = rangetosubnet( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_rsasigkey.8.html b/doc/manpage.d/ipsec_rsasigkey.8.html
new file mode 100644
index 000000000..3173a9f13
--- /dev/null
+++ b/doc/manpage.d/ipsec_rsasigkey.8.html
@@ -0,0 +1,401 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_RSASIGKEY</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_RSASIGKEY</H1>
+Section: Maintenance Commands (8)<BR>Updated: 22 July 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec rsasigkey - generate RSA signature key
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>rsasigkey</B>
+
+[
+<B>--verbose</B>
+
+] [
+<B>--random</B>
+
+filename
+]
+<B>\</B>
+
+<BR>
+
+&nbsp;&nbsp;&nbsp;[
+<B>--rounds</B>
+
+nr
+] [
+<B>--hostname</B>
+
+host ] [
+<B>--noopt</B>
+
+] nbits
+<BR>
+
+<B>ipsec</B>
+
+<B>rsasigkey</B>
+
+[
+<B>--verbose</B>
+
+] [
+<B>--hostname</B>
+
+host ]
+<B>\</B>
+
+<BR>
+
+&nbsp;&nbsp;&nbsp;
+[
+<B>--noopt</B>
+
+]
+<B>--oldkey</B>
+
+file
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Rsasigkey</I>
+
+generates an RSA public/private key pair,
+suitable for digital signatures,
+of (exactly)
+<I>nbits</I>
+
+bits (that is, two primes each of exactly
+<I>nbits</I>/2
+
+bits,
+and related numbers)
+and emits it on standard output as ASCII (mostly hex) data.
+<I>nbits</I>
+
+must be a multiple of 16.
+<P>
+
+The public exponent is forced to the value
+<B>3</B>,
+
+which has important speed advantages for signature checking.
+Beware that the resulting keys have known weaknesses as encryption keys
+<I>and should not be used for that purpose</I>.
+<P>
+
+The
+<B>--verbose</B>
+
+option makes
+<I>rsasigkey</I>
+
+give a running commentary on standard error.
+By default, it works in silence until it is ready to generate output.
+<P>
+
+The
+<B>--random</B>
+
+option specifies a source for random bits.
+The default is
+<I>/dev/random</I>
+
+(see
+<I><A HREF="random.4.html">random</A></I>(4)).
+
+Normally,
+<I>rsasigkey</I>
+
+reads exactly
+<I>nbits</I>
+
+random bits from the source;
+in extremely-rare circumstances it may need more.
+<P>
+
+The
+<B>--rounds</B>
+
+option specifies the number of rounds to be done by the
+<I>mpz_probab_prime_p</I>
+
+probabilistic primality checker.
+The default, 30, is fairly rigorous and should not normally
+have to be overridden.
+<P>
+
+The
+<B>--hostname</B>
+
+option specifies what host name to use in
+the first line of the output (see below);
+the default is what
+<I><A HREF="gethostname.2.html">gethostname</A></I>(2)
+
+returns.
+<P>
+
+The
+<B>--noopt</B>
+
+option suppresses an optimization of the private key
+(to be precise, setting of the decryption exponent to
+<B>lcm(p-1,q-1)</B>
+
+rather than
+<B>(p-1)*(q-1)</B>)
+
+which speeds up operations on it slightly
+but can cause it to flunk a validity check in old RSA implementations
+(notably, obsolete versions of
+<I><A HREF="ipsec_pluto.8.html">ipsec_pluto</A></I>(8)).
+
+<P>
+
+The
+<B>--oldkey</B>
+
+option specifies that rather than generate a new key,
+<I>rsasigkey</I>
+
+should read an old key from the
+<I>file</I>
+
+(the name
+<B>-</B>
+
+means ``standard input'')
+and use that to generate its output.
+Input lines which do not look like
+<I>rsasigkey</I>
+
+output are silently ignored.
+This permits updating old keys to the current format.
+<P>
+
+The output format looks like this (with long numbers trimmed down
+for clarity):
+<P>
+
+
+<PRE>
+        # RSA 2048 bits   xy.example.com   Sat Apr 15 13:53:22 2000
+        # for signatures only, UNSAFE FOR ENCRYPTION
+        #pubkey=0sAQOF8tZ2NZt...Y1P+buFuFn/
+        Modulus: 0xcc2a86fcf440...cf1011abb82d1
+        PublicExponent: 0x03
+        # everything after this point is secret
+        PrivateExponent: 0x881c59fdf8...ab05c8c77d23
+        Prime1: 0xf49fd1f779...46504c7bf3
+        Prime2: 0xd5a9108453...321d43cb2b
+        Exponent1: 0xa31536a4fb...536d98adda7f7
+        Exponent2: 0x8e70b5ad8d...9142168d7dcc7
+        Coefficient: 0xafb761d001...0c13e98d98
+</PRE>
+
+<P>
+
+The first (comment) line,
+indicating the nature and date of the key,
+and giving a host name,
+is used by
+<I><A HREF="ipsec_showhostkey.8.html">ipsec_showhostkey</A></I>(8)
+
+when generating some forms of key output.
+<P>
+
+The commented-out
+<B>pubkey=</B>
+
+line contains the public key---the public exponent and the modulus---combined
+in approximately RFC 2537 format
+(the one deviation is that the combined value is given with a
+<B>0s</B>
+
+prefix, rather than in unadorned base-64),
+suitable for use in the
+<I>ipsec.conf</I>
+
+file.
+<P>
+
+The
+<B>Modulus</B>,
+
+<B>PublicExponent</B>,
+
+and
+<B>PrivateExponent</B>
+
+lines give the basic signing and verification data.
+<P>
+
+The
+<B>Prime1</B>
+
+and
+<B>Prime2</B>
+
+lines give the primes themselves (aka
+<I>p</I>
+
+and
+<I>q</I>),
+
+largest first.
+The
+<B>Exponent1</B>
+
+and
+<B>Exponent2</B>
+
+lines give
+the private exponent mod
+<I>p-1</I>
+
+and
+<I>q-1</I>
+
+respectively.
+The
+<B>Coefficient</B>
+
+line gives the Chinese Remainder Theorem coefficient,
+which is the inverse of
+<I>q</I>,
+
+mod
+<I>p</I>.
+
+These additional numbers (which must all be kept as secret as the
+private exponent) are precomputed aids to rapid signature generation.
+<P>
+
+No attempt is made to break long lines.
+<P>
+
+The US patent on the RSA algorithm expired 20 Sept 2000.
+<A NAME="lbAE">&nbsp;</A>
+<H2>EXAMPLES</H2>
+
+<DL COMPACT>
+<DT><B>ipsec rsasigkey --verbose 2192 &gt;mykey</B>
+
+<DD>
+generates a 2192-bit signature key and puts it in the file
+<I>mykey</I>,
+
+with running commentary on standard error.
+The file contents can be inserted verbatim into a suitable entry in the
+<I>ipsec.secrets</I>
+
+file (see
+<I><A HREF="ipsec.secrets.5.html">ipsec.secrets</A></I>(5)),
+
+and the public key can then be extracted and edited into the
+<I>ipsec.conf</I>
+
+file (see
+<I><A HREF="ipsec.conf.5.html">ipsec.conf</A></I>(5)).
+
+<DT><B>ipsec rsasigkey --verbose --oldkey oldie &gt;latest</B>
+
+<DD>
+takes the old signature key from file
+<I>oldie</I>
+
+and puts a version in the current format into the file
+<I>latest</I>,
+
+with running commentary on standard error.
+</DL>
+<A NAME="lbAF">&nbsp;</A>
+<H2>FILES</H2>
+
+/dev/random
+<A NAME="lbAG">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="random.4.html">random</A>(4), <A HREF="ipsec_showhostkey.8.html">ipsec_showhostkey</A>(8)
+<BR>
+
+<I>Applied Cryptography</I>, 2nd. ed., by Bruce Schneier, Wiley 1996.
+<BR>
+
+RFCs 2537, 2313.
+<BR>
+
+<I>GNU MP, the GNU multiple precision arithmetic library, edition 2.0.2</I>,
+by Torbj Granlund.
+<A NAME="lbAH">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org">http://www.freeswan.org</A>&gt;
+by Henry Spencer.
+<A NAME="lbAI">&nbsp;</A>
+<H2>BUGS</H2>
+
+There is an internal limit on
+<I>nbits</I>,
+
+currently 20000.
+<P>
+
+<I>Rsasigkey</I>'s
+
+run time is difficult to predict,
+since
+<I>/dev/random</I>
+
+output can be arbitrarily delayed if
+the system's entropy pool is low on randomness,
+and the time taken by the search for primes is also somewhat unpredictable.
+A reasonably typical time for a 1024-bit key on a quiet 200MHz Pentium MMX
+with plenty of randomness available is 20 seconds,
+almost all of it in the prime searches.
+Generating a 2192-bit key on the same system usually takes several minutes.
+A 4096-bit key took an hour and a half of CPU time.
+<P>
+
+The
+<B>--oldkey</B>
+
+option does not check its input format as rigorously as it might.
+Corrupted
+<I>rsasigkey</I>
+
+output may confuse it.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">EXAMPLES</A><DD>
+<DT><A HREF="#lbAF">FILES</A><DD>
+<DT><A HREF="#lbAG">SEE ALSO</A><DD>
+<DT><A HREF="#lbAH">HISTORY</A><DD>
+<DT><A HREF="#lbAI">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_sameaddr.3.html b/doc/manpage.d/ipsec_sameaddr.3.html
new file mode 100644
index 000000000..414a0d513
--- /dev/null
+++ b/doc/manpage.d/ipsec_sameaddr.3.html
@@ -0,0 +1,274 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ANYADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ANYADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 28 Nov 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec sameaddr - are two addresses the same?
+<BR>
+
+ipsec addrcmp - ordered comparison of addresses
+<BR>
+
+ipsec samesubnet - are two subnets the same?
+<BR>
+
+ipsec addrinsubnet - is an address within a subnet?
+<BR>
+
+ipsec subnetinsubnet - is a subnet within another subnet?
+<BR>
+
+ipsec subnetishost - is a subnet a single host?
+<BR>
+
+ipsec samesaid - are two SA IDs the same?
+<BR>
+
+ipsec sameaddrtype - are two addresses of the same address family?
+<BR>
+
+ipsec samesubnettype - are two subnets of the same address family?
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>int sameaddr(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int addrcmp(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int samesubnet(const ip_subnet *a, const ip_subnet *b);</B>
+
+<BR>
+
+<B>int addrinsubnet(const ip_address *a, const ip_subnet *s);</B>
+
+<BR>
+
+<B>int subnetinsubnet(const ip_subnet *a, const ip_subnet *b);</B>
+
+<BR>
+
+<B>int subnetishost(const ip_subnet *s);</B>
+
+<BR>
+
+<B>int samesaid(const ip_said *a, const ip_said *b);</B>
+
+<BR>
+
+<B>int sameaddrtype(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int samesubnettype(const ip_subnet *a, const ip_subnet *b);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions do various comparisons and tests on the
+<I>ip_address</I>
+
+type and
+<I>ip_subnet</I>
+
+types.
+<P>
+
+<I>Sameaddr</I>
+
+returns
+non-zero
+if addresses
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+Addresses of different families are never identical.
+<P>
+
+<I>Addrcmp</I>
+
+returns
+<B>-1</B>,
+
+<B>0</B>,
+
+or
+<B>1</B>
+
+respectively
+if address
+<I>a</I>
+
+is less than, equal to, or greater than
+<I>b</I>.
+
+If they are not of the same address family,
+they are never equal;
+the ordering reported in this case is arbitrary
+(and probably not useful) but consistent.
+<P>
+
+<I>Samesubnet</I>
+
+returns
+non-zero
+if subnets
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+Subnets of different address families are never identical.
+<P>
+
+<I>Addrinsubnet</I>
+
+returns
+non-zero
+if address
+<I>a</I>
+
+is within subnet
+<I>s</I>
+
+and
+<B>0</B>
+
+otherwise.
+An address is never within a
+subnet of a different address family.
+<P>
+
+<I>Subnetinsubnet</I>
+
+returns
+non-zero
+if subnet
+<I>a</I>
+
+is a subset of subnet
+<I>b</I>
+
+and
+<B>0</B>
+
+otherwise.
+A subnet is deemed to be a subset of itself.
+A subnet is never a subset of another
+subnet if their address families differ.
+<P>
+
+<I>Subnetishost</I>
+
+returns
+non-zero
+if subnet
+<I>s</I>
+
+is in fact only a single host,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Samesaid</I>
+
+returns
+non-zero
+if SA IDs
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Sameaddrtype</I>
+
+returns
+non-zero
+if addresses
+<I>a</I>
+
+and
+<I>b</I>
+
+are of the same address family,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Samesubnettype</I>
+
+returns
+non-zero
+if subnets
+<I>a</I>
+
+and
+<I>b</I>
+
+are of the same address family,
+and
+<B>0</B>
+
+otherwise.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_initaddr.3.html">ipsec_initaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_sameaddrtype.3.html b/doc/manpage.d/ipsec_sameaddrtype.3.html
new file mode 100644
index 000000000..414a0d513
--- /dev/null
+++ b/doc/manpage.d/ipsec_sameaddrtype.3.html
@@ -0,0 +1,274 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ANYADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ANYADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 28 Nov 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec sameaddr - are two addresses the same?
+<BR>
+
+ipsec addrcmp - ordered comparison of addresses
+<BR>
+
+ipsec samesubnet - are two subnets the same?
+<BR>
+
+ipsec addrinsubnet - is an address within a subnet?
+<BR>
+
+ipsec subnetinsubnet - is a subnet within another subnet?
+<BR>
+
+ipsec subnetishost - is a subnet a single host?
+<BR>
+
+ipsec samesaid - are two SA IDs the same?
+<BR>
+
+ipsec sameaddrtype - are two addresses of the same address family?
+<BR>
+
+ipsec samesubnettype - are two subnets of the same address family?
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>int sameaddr(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int addrcmp(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int samesubnet(const ip_subnet *a, const ip_subnet *b);</B>
+
+<BR>
+
+<B>int addrinsubnet(const ip_address *a, const ip_subnet *s);</B>
+
+<BR>
+
+<B>int subnetinsubnet(const ip_subnet *a, const ip_subnet *b);</B>
+
+<BR>
+
+<B>int subnetishost(const ip_subnet *s);</B>
+
+<BR>
+
+<B>int samesaid(const ip_said *a, const ip_said *b);</B>
+
+<BR>
+
+<B>int sameaddrtype(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int samesubnettype(const ip_subnet *a, const ip_subnet *b);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions do various comparisons and tests on the
+<I>ip_address</I>
+
+type and
+<I>ip_subnet</I>
+
+types.
+<P>
+
+<I>Sameaddr</I>
+
+returns
+non-zero
+if addresses
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+Addresses of different families are never identical.
+<P>
+
+<I>Addrcmp</I>
+
+returns
+<B>-1</B>,
+
+<B>0</B>,
+
+or
+<B>1</B>
+
+respectively
+if address
+<I>a</I>
+
+is less than, equal to, or greater than
+<I>b</I>.
+
+If they are not of the same address family,
+they are never equal;
+the ordering reported in this case is arbitrary
+(and probably not useful) but consistent.
+<P>
+
+<I>Samesubnet</I>
+
+returns
+non-zero
+if subnets
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+Subnets of different address families are never identical.
+<P>
+
+<I>Addrinsubnet</I>
+
+returns
+non-zero
+if address
+<I>a</I>
+
+is within subnet
+<I>s</I>
+
+and
+<B>0</B>
+
+otherwise.
+An address is never within a
+subnet of a different address family.
+<P>
+
+<I>Subnetinsubnet</I>
+
+returns
+non-zero
+if subnet
+<I>a</I>
+
+is a subset of subnet
+<I>b</I>
+
+and
+<B>0</B>
+
+otherwise.
+A subnet is deemed to be a subset of itself.
+A subnet is never a subset of another
+subnet if their address families differ.
+<P>
+
+<I>Subnetishost</I>
+
+returns
+non-zero
+if subnet
+<I>s</I>
+
+is in fact only a single host,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Samesaid</I>
+
+returns
+non-zero
+if SA IDs
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Sameaddrtype</I>
+
+returns
+non-zero
+if addresses
+<I>a</I>
+
+and
+<I>b</I>
+
+are of the same address family,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Samesubnettype</I>
+
+returns
+non-zero
+if subnets
+<I>a</I>
+
+and
+<I>b</I>
+
+are of the same address family,
+and
+<B>0</B>
+
+otherwise.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_initaddr.3.html">ipsec_initaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_samesaid.3.html b/doc/manpage.d/ipsec_samesaid.3.html
new file mode 100644
index 000000000..414a0d513
--- /dev/null
+++ b/doc/manpage.d/ipsec_samesaid.3.html
@@ -0,0 +1,274 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ANYADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ANYADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 28 Nov 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec sameaddr - are two addresses the same?
+<BR>
+
+ipsec addrcmp - ordered comparison of addresses
+<BR>
+
+ipsec samesubnet - are two subnets the same?
+<BR>
+
+ipsec addrinsubnet - is an address within a subnet?
+<BR>
+
+ipsec subnetinsubnet - is a subnet within another subnet?
+<BR>
+
+ipsec subnetishost - is a subnet a single host?
+<BR>
+
+ipsec samesaid - are two SA IDs the same?
+<BR>
+
+ipsec sameaddrtype - are two addresses of the same address family?
+<BR>
+
+ipsec samesubnettype - are two subnets of the same address family?
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>int sameaddr(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int addrcmp(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int samesubnet(const ip_subnet *a, const ip_subnet *b);</B>
+
+<BR>
+
+<B>int addrinsubnet(const ip_address *a, const ip_subnet *s);</B>
+
+<BR>
+
+<B>int subnetinsubnet(const ip_subnet *a, const ip_subnet *b);</B>
+
+<BR>
+
+<B>int subnetishost(const ip_subnet *s);</B>
+
+<BR>
+
+<B>int samesaid(const ip_said *a, const ip_said *b);</B>
+
+<BR>
+
+<B>int sameaddrtype(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int samesubnettype(const ip_subnet *a, const ip_subnet *b);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions do various comparisons and tests on the
+<I>ip_address</I>
+
+type and
+<I>ip_subnet</I>
+
+types.
+<P>
+
+<I>Sameaddr</I>
+
+returns
+non-zero
+if addresses
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+Addresses of different families are never identical.
+<P>
+
+<I>Addrcmp</I>
+
+returns
+<B>-1</B>,
+
+<B>0</B>,
+
+or
+<B>1</B>
+
+respectively
+if address
+<I>a</I>
+
+is less than, equal to, or greater than
+<I>b</I>.
+
+If they are not of the same address family,
+they are never equal;
+the ordering reported in this case is arbitrary
+(and probably not useful) but consistent.
+<P>
+
+<I>Samesubnet</I>
+
+returns
+non-zero
+if subnets
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+Subnets of different address families are never identical.
+<P>
+
+<I>Addrinsubnet</I>
+
+returns
+non-zero
+if address
+<I>a</I>
+
+is within subnet
+<I>s</I>
+
+and
+<B>0</B>
+
+otherwise.
+An address is never within a
+subnet of a different address family.
+<P>
+
+<I>Subnetinsubnet</I>
+
+returns
+non-zero
+if subnet
+<I>a</I>
+
+is a subset of subnet
+<I>b</I>
+
+and
+<B>0</B>
+
+otherwise.
+A subnet is deemed to be a subset of itself.
+A subnet is never a subset of another
+subnet if their address families differ.
+<P>
+
+<I>Subnetishost</I>
+
+returns
+non-zero
+if subnet
+<I>s</I>
+
+is in fact only a single host,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Samesaid</I>
+
+returns
+non-zero
+if SA IDs
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Sameaddrtype</I>
+
+returns
+non-zero
+if addresses
+<I>a</I>
+
+and
+<I>b</I>
+
+are of the same address family,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Samesubnettype</I>
+
+returns
+non-zero
+if subnets
+<I>a</I>
+
+and
+<I>b</I>
+
+are of the same address family,
+and
+<B>0</B>
+
+otherwise.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_initaddr.3.html">ipsec_initaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_samesubnet.3.html b/doc/manpage.d/ipsec_samesubnet.3.html
new file mode 100644
index 000000000..414a0d513
--- /dev/null
+++ b/doc/manpage.d/ipsec_samesubnet.3.html
@@ -0,0 +1,274 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ANYADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ANYADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 28 Nov 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec sameaddr - are two addresses the same?
+<BR>
+
+ipsec addrcmp - ordered comparison of addresses
+<BR>
+
+ipsec samesubnet - are two subnets the same?
+<BR>
+
+ipsec addrinsubnet - is an address within a subnet?
+<BR>
+
+ipsec subnetinsubnet - is a subnet within another subnet?
+<BR>
+
+ipsec subnetishost - is a subnet a single host?
+<BR>
+
+ipsec samesaid - are two SA IDs the same?
+<BR>
+
+ipsec sameaddrtype - are two addresses of the same address family?
+<BR>
+
+ipsec samesubnettype - are two subnets of the same address family?
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>int sameaddr(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int addrcmp(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int samesubnet(const ip_subnet *a, const ip_subnet *b);</B>
+
+<BR>
+
+<B>int addrinsubnet(const ip_address *a, const ip_subnet *s);</B>
+
+<BR>
+
+<B>int subnetinsubnet(const ip_subnet *a, const ip_subnet *b);</B>
+
+<BR>
+
+<B>int subnetishost(const ip_subnet *s);</B>
+
+<BR>
+
+<B>int samesaid(const ip_said *a, const ip_said *b);</B>
+
+<BR>
+
+<B>int sameaddrtype(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int samesubnettype(const ip_subnet *a, const ip_subnet *b);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions do various comparisons and tests on the
+<I>ip_address</I>
+
+type and
+<I>ip_subnet</I>
+
+types.
+<P>
+
+<I>Sameaddr</I>
+
+returns
+non-zero
+if addresses
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+Addresses of different families are never identical.
+<P>
+
+<I>Addrcmp</I>
+
+returns
+<B>-1</B>,
+
+<B>0</B>,
+
+or
+<B>1</B>
+
+respectively
+if address
+<I>a</I>
+
+is less than, equal to, or greater than
+<I>b</I>.
+
+If they are not of the same address family,
+they are never equal;
+the ordering reported in this case is arbitrary
+(and probably not useful) but consistent.
+<P>
+
+<I>Samesubnet</I>
+
+returns
+non-zero
+if subnets
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+Subnets of different address families are never identical.
+<P>
+
+<I>Addrinsubnet</I>
+
+returns
+non-zero
+if address
+<I>a</I>
+
+is within subnet
+<I>s</I>
+
+and
+<B>0</B>
+
+otherwise.
+An address is never within a
+subnet of a different address family.
+<P>
+
+<I>Subnetinsubnet</I>
+
+returns
+non-zero
+if subnet
+<I>a</I>
+
+is a subset of subnet
+<I>b</I>
+
+and
+<B>0</B>
+
+otherwise.
+A subnet is deemed to be a subset of itself.
+A subnet is never a subset of another
+subnet if their address families differ.
+<P>
+
+<I>Subnetishost</I>
+
+returns
+non-zero
+if subnet
+<I>s</I>
+
+is in fact only a single host,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Samesaid</I>
+
+returns
+non-zero
+if SA IDs
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Sameaddrtype</I>
+
+returns
+non-zero
+if addresses
+<I>a</I>
+
+and
+<I>b</I>
+
+are of the same address family,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Samesubnettype</I>
+
+returns
+non-zero
+if subnets
+<I>a</I>
+
+and
+<I>b</I>
+
+are of the same address family,
+and
+<B>0</B>
+
+otherwise.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_initaddr.3.html">ipsec_initaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_samesubnettype.3.html b/doc/manpage.d/ipsec_samesubnettype.3.html
new file mode 100644
index 000000000..414a0d513
--- /dev/null
+++ b/doc/manpage.d/ipsec_samesubnettype.3.html
@@ -0,0 +1,274 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ANYADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ANYADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 28 Nov 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec sameaddr - are two addresses the same?
+<BR>
+
+ipsec addrcmp - ordered comparison of addresses
+<BR>
+
+ipsec samesubnet - are two subnets the same?
+<BR>
+
+ipsec addrinsubnet - is an address within a subnet?
+<BR>
+
+ipsec subnetinsubnet - is a subnet within another subnet?
+<BR>
+
+ipsec subnetishost - is a subnet a single host?
+<BR>
+
+ipsec samesaid - are two SA IDs the same?
+<BR>
+
+ipsec sameaddrtype - are two addresses of the same address family?
+<BR>
+
+ipsec samesubnettype - are two subnets of the same address family?
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>int sameaddr(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int addrcmp(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int samesubnet(const ip_subnet *a, const ip_subnet *b);</B>
+
+<BR>
+
+<B>int addrinsubnet(const ip_address *a, const ip_subnet *s);</B>
+
+<BR>
+
+<B>int subnetinsubnet(const ip_subnet *a, const ip_subnet *b);</B>
+
+<BR>
+
+<B>int subnetishost(const ip_subnet *s);</B>
+
+<BR>
+
+<B>int samesaid(const ip_said *a, const ip_said *b);</B>
+
+<BR>
+
+<B>int sameaddrtype(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int samesubnettype(const ip_subnet *a, const ip_subnet *b);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions do various comparisons and tests on the
+<I>ip_address</I>
+
+type and
+<I>ip_subnet</I>
+
+types.
+<P>
+
+<I>Sameaddr</I>
+
+returns
+non-zero
+if addresses
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+Addresses of different families are never identical.
+<P>
+
+<I>Addrcmp</I>
+
+returns
+<B>-1</B>,
+
+<B>0</B>,
+
+or
+<B>1</B>
+
+respectively
+if address
+<I>a</I>
+
+is less than, equal to, or greater than
+<I>b</I>.
+
+If they are not of the same address family,
+they are never equal;
+the ordering reported in this case is arbitrary
+(and probably not useful) but consistent.
+<P>
+
+<I>Samesubnet</I>
+
+returns
+non-zero
+if subnets
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+Subnets of different address families are never identical.
+<P>
+
+<I>Addrinsubnet</I>
+
+returns
+non-zero
+if address
+<I>a</I>
+
+is within subnet
+<I>s</I>
+
+and
+<B>0</B>
+
+otherwise.
+An address is never within a
+subnet of a different address family.
+<P>
+
+<I>Subnetinsubnet</I>
+
+returns
+non-zero
+if subnet
+<I>a</I>
+
+is a subset of subnet
+<I>b</I>
+
+and
+<B>0</B>
+
+otherwise.
+A subnet is deemed to be a subset of itself.
+A subnet is never a subset of another
+subnet if their address families differ.
+<P>
+
+<I>Subnetishost</I>
+
+returns
+non-zero
+if subnet
+<I>s</I>
+
+is in fact only a single host,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Samesaid</I>
+
+returns
+non-zero
+if SA IDs
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Sameaddrtype</I>
+
+returns
+non-zero
+if addresses
+<I>a</I>
+
+and
+<I>b</I>
+
+are of the same address family,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Samesubnettype</I>
+
+returns
+non-zero
+if subnets
+<I>a</I>
+
+and
+<I>b</I>
+
+are of the same address family,
+and
+<B>0</B>
+
+otherwise.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_initaddr.3.html">ipsec_initaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_satoa.3.html b/doc/manpage.d/ipsec_satoa.3.html
new file mode 100644
index 000000000..2b2c7425c
--- /dev/null
+++ b/doc/manpage.d/ipsec_satoa.3.html
@@ -0,0 +1,347 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ATOSA</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ATOSA</H1>
+Section: C Library Functions (3)<BR>Updated: 11 June 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec atosa, satoa - convert IPsec Security Association IDs to and from ASCII
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *atosa(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>struct sa_id *sa);</B>
+
+<BR>
+
+<B>size_t satoa(struct sa_id sa, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<P>
+<B>struct sa_id {</B>
+
+<BR>
+&nbsp;
+<B>struct in_addr dst;</B>
+
+<BR>
+&nbsp;
+<B>ipsec_spi_t spi;</B>
+
+<BR>
+&nbsp;
+<B>int proto;</B>
+
+<BR>
+
+<B>};</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions are obsolete; see
+<I><A HREF="ipsec_ttosa.3.html">ipsec_ttosa</A></I>(3)
+
+for their replacements.
+<P>
+
+<I>Atosa</I>
+
+converts an ASCII Security Association (SA) specifier into an
+<B>sa_id</B>
+
+structure (containing
+a destination-host address
+in network byte order,
+an SPI number in network byte order, and
+a protocol code).
+<I>Satoa</I>
+
+does the reverse conversion, back to an ASCII SA specifier.
+<P>
+
+An SA is specified in ASCII with a mail-like syntax, e.g.
+<B><A HREF="mailto:esp507@1.2.3.4">esp507@1.2.3.4</A></B>.
+
+An SA specifier contains
+a protocol prefix (currently
+<B>ah</B>,
+
+<B>esp</B>,
+
+or
+<B>tun</B>),
+
+an unsigned integer SPI number,
+and an IP address.
+The SPI number can be decimal or hexadecimal
+(with
+<B>0x</B>
+
+prefix), as accepted by
+<I><A HREF="ipsec_atoul.3.html">ipsec_atoul</A></I>(3).
+
+The IP address can be any form accepted by
+<I><A HREF="ipsec_atoaddr.3.html">ipsec_atoaddr</A></I>(3),
+
+e.g. dotted-decimal address or DNS name.
+<P>
+
+As a special case, the SA specifier
+<B>%passthrough</B>
+
+signifies the special SA used to indicate that packets should be
+passed through unaltered.
+(At present, this is a synonym for
+<B><A HREF="mailto:tun0x0@0.0.0.0">tun0x0@0.0.0.0</A></B>,
+
+but that is subject to change without notice.)
+This form is known to both
+<I>atosa</I>
+
+and
+<I>satoa</I>,
+
+so the internal form of
+<B>%passthrough</B>
+
+is never visible.
+<P>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file supplies the
+<B>sa_id</B>
+
+structure, as well as a data type
+<B>ipsec_spi_t</B>
+
+which is an unsigned 32-bit integer.
+(There is no consistency between kernel and user on what such a type
+is called, hence the header hides the differences.)
+<P>
+
+The protocol code uses the same numbers that IP does.
+For user convenience, given the difficulty in acquiring the exact set of
+protocol names used by the kernel,
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+defines the names
+<B>SA_ESP</B>,
+
+<B>SA_AH</B>,
+
+and
+<B>SA_IPIP</B>
+
+to have the same values as the kernel names
+<B>IPPROTO_ESP</B>,
+
+<B>IPPROTO_AH</B>,
+
+and
+<B>IPPROTO_IPIP</B>.
+
+<P>
+
+The
+<I>srclen</I>
+
+parameter of
+<I>atosa</I>
+
+specifies the length of the ASCII string pointed to by
+<I>src</I>;
+
+it is an error for there to be anything else
+(e.g., a terminating NUL) within that length.
+As a convenience for cases where an entire NUL-terminated string is
+to be converted,
+a
+<I>srclen</I>
+
+value of
+<B>0</B>
+
+is taken to mean
+<B>strlen(src)</B>.
+
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of
+<I>satoa</I>
+
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+The
+<I>freeswan.h</I>
+
+header file defines a constant,
+<B>SATOA_BUF</B>,
+
+which is the size of a buffer just large enough for worst-case results.
+<P>
+
+The
+<I>format</I>
+
+parameter of
+<I>satoa</I>
+
+specifies what format is to be used for the conversion.
+The value
+<B>0</B>
+
+(not the ASCII character
+<B>'0'</B>,
+
+but a zero value)
+specifies a reasonable default
+(currently
+lowercase protocol prefix, lowercase hexadecimal SPI, dotted-decimal address).
+The value
+<B>d</B>
+
+causes the SPI to be generated in decimal instead.
+<P>
+
+<I>Atosa</I>
+
+returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<I>Satoa</I>
+
+returns
+<B>0</B>
+
+for a failure, and otherwise
+always returns the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL;
+it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec_atoul.3.html">ipsec_atoul</A>(3), <A HREF="ipsec_atoaddr.3.html">ipsec_atoaddr</A>(3), <A HREF="inet.3.html">inet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>atosa</I>
+
+are:
+empty input;
+input too small to be a legal SA specifier;
+no
+<B>@</B>
+
+in input;
+unknown protocol prefix;
+conversion error in
+<I>atoul</I>
+
+or
+<I>atoaddr</I>.
+
+<P>
+
+Fatal errors in
+<I>satoa</I>
+
+are:
+unknown format; unknown protocol code.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+The
+<B>tun</B>
+
+protocol code is a FreeS/WANism which may eventually disappear.
+<P>
+
+The restriction of ASCII-to-binary error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The ASCII-to-binary error-reporting convention lends itself
+to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = atoaddr( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_satot.3.html b/doc/manpage.d/ipsec_satot.3.html
new file mode 100644
index 000000000..1e457fc24
--- /dev/null
+++ b/doc/manpage.d/ipsec_satot.3.html
@@ -0,0 +1,453 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_TTOSA</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_TTOSA</H1>
+Section: C Library Functions (3)<BR>Updated: 26 Nov 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec ttosa, satot - convert IPsec Security Association IDs to and from text
+<BR>
+
+ipsec initsaid - initialize an SA ID
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>typedef struct {</B>
+
+<BR>
+&nbsp;
+<B>ip_address dst;</B>
+
+<BR>
+&nbsp;
+<B>ipsec_spi_t spi;</B>
+
+<BR>
+&nbsp;
+<B>int proto;</B>
+
+<BR>
+
+<B>} ip_said;</B>
+
+<P>
+<B>const char *ttosa(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>ip_said *sa);</B>
+
+<BR>
+
+<B>size_t satot(const ip_said *sa, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<BR>
+
+<B>void initsaid(const ip_address *addr, ipsec_spi_t spi,</B>
+
+<BR>
+&nbsp;
+<B>int proto, ip_said *dst);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Ttosa</I>
+
+converts an ASCII Security Association (SA) specifier into an
+<B>ip_said</B>
+
+structure (containing
+a destination-host address
+in network byte order,
+an SPI number in network byte order, and
+a protocol code).
+<I>Satot</I>
+
+does the reverse conversion, back to a text SA specifier.
+<I>Initsaid</I>
+
+initializes an
+<B>ip_said</B>
+
+from separate items of information.
+<P>
+
+An SA is specified in text with a mail-like syntax, e.g.
+<B><A HREF="mailto:esp.5a7@1.2.3.4">esp.5a7@1.2.3.4</A></B>.
+
+An SA specifier contains
+a protocol prefix (currently
+<B>ah</B>,
+
+<B>esp</B>,
+
+<B>tun</B>,
+
+<B>comp</B>,
+
+or
+<B>int</B>),
+
+a single character indicating the address family
+(<B>.</B>
+
+for IPv4,
+<B>:</B>
+
+for IPv6),
+an unsigned integer SPI number in hexadecimal (with no
+<B>0x</B>
+
+prefix),
+and an IP address.
+The IP address can be any form accepted by
+<I><A HREF="ipsec_ttoaddr.3.html">ipsec_ttoaddr</A></I>(3),
+
+e.g. dotted-decimal IPv4 address,
+colon-hex IPv6 address,
+or DNS name.
+<P>
+
+As a special case, the SA specifier
+<B>%passthrough4</B>
+
+or
+<B>%passthrough6</B>
+
+signifies the special SA used to indicate that packets should be
+passed through unaltered.
+(At present, these are synonyms for
+<B><A HREF="mailto:tun.0@0.0.0.0">tun.0@0.0.0.0</A></B>
+
+and
+<B>tun:0@::</B>
+
+respectively,
+but that is subject to change without notice.)
+<B>%passthrough</B>
+
+is a historical synonym for
+<B>%passthrough4</B>.
+
+These forms are known to both
+<I>ttosa</I>
+
+and
+<I>satot</I>,
+
+so the internal representation is never visible.
+<P>
+
+Similarly, the SA specifiers
+<B>%pass</B>,
+
+<B>%drop</B>,
+
+<B>%reject</B>,
+
+<B>%hold</B>,
+
+<B>%trap</B>,
+
+and
+<B>%trapsubnet</B>
+
+signify special ``magic'' SAs used to indicate that packets should be
+passed, dropped, rejected (dropped with ICMP notification),
+held,
+and trapped (sent up to
+<I><A HREF="ipsec_pluto.8.html">ipsec_pluto</A></I>(8),
+
+with either of two forms of
+<B>%hold</B>
+
+automatically installed)
+respectively.
+These forms too are known to both routines,
+so the internal representation of the magic SAs should never be visible.
+<P>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file supplies the
+<B>ip_said</B>
+
+structure, as well as a data type
+<B>ipsec_spi_t</B>
+
+which is an unsigned 32-bit integer.
+(There is no consistency between kernel and user on what such a type
+is called, hence the header hides the differences.)
+<P>
+
+The protocol code uses the same numbers that IP does.
+For user convenience, given the difficulty in acquiring the exact set of
+protocol names used by the kernel,
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+defines the names
+<B>SA_ESP</B>,
+
+<B>SA_AH</B>,
+
+<B>SA_IPIP</B>,
+
+and
+<B>SA_COMP</B>
+
+to have the same values as the kernel names
+<B>IPPROTO_ESP</B>,
+
+<B>IPPROTO_AH</B>,
+
+<B>IPPROTO_IPIP</B>,
+
+and
+<B>IPPROTO_COMP</B>.
+
+<P>
+
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+also defines
+<B>SA_INT</B>
+
+to have the value
+<B>61</B>
+
+(reserved by IANA for ``any host internal protocol'')
+and
+<B>SPI_PASS</B>,
+
+<B>SPI_DROP</B>,
+
+<B>SPI_REJECT</B>,
+
+<B>SPI_HOLD</B>,
+
+and
+<B>SPI_TRAP</B>
+
+to have the values 256-260 (in <I>host</I> byte order) respectively.
+These are used in constructing the magic SAs
+(which always have address
+<B>0.0.0.0</B>).
+
+<P>
+
+If
+<I>satot</I>
+
+encounters an unknown protocol code, e.g. 77,
+it yields output using a prefix
+showing the code numerically, e.g. ``unk77''.
+This form is
+<I>not</I>
+
+recognized by
+<I>ttosa</I>.
+
+<P>
+
+The
+<I>srclen</I>
+
+parameter of
+<I>ttosa</I>
+
+specifies the length of the string pointed to by
+<I>src</I>;
+
+it is an error for there to be anything else
+(e.g., a terminating NUL) within that length.
+As a convenience for cases where an entire NUL-terminated string is
+to be converted,
+a
+<I>srclen</I>
+
+value of
+<B>0</B>
+
+is taken to mean
+<B>strlen(src)</B>.
+
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of
+<I>satot</I>
+
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file defines a constant,
+<B>SATOT_BUF</B>,
+
+which is the size of a buffer just large enough for worst-case results.
+<P>
+
+The
+<I>format</I>
+
+parameter of
+<I>satot</I>
+
+specifies what format is to be used for the conversion.
+The value
+<B>0</B>
+
+(not the ASCII character
+<B>'0'</B>,
+
+but a zero value)
+specifies a reasonable default
+(currently
+lowercase protocol prefix, lowercase hexadecimal SPI,
+dotted-decimal or colon-hex address).
+The value
+<B>'f'</B>
+
+is similar except that the SPI is padded with
+<B>0</B>s
+
+to a fixed 32-bit width, to ease aligning displayed tables.
+<P>
+
+<I>Ttosa</I>
+
+returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<I>Satot</I>
+
+returns
+<B>0</B>
+
+for a failure, and otherwise
+always returns the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL;
+it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred.
+<P>
+
+There is also, temporarily, support for some obsolete
+forms of SA specifier which lack the address-family indicator.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec_ttoul.3.html">ipsec_ttoul</A>(3), <A HREF="ipsec_ttoaddr.3.html">ipsec_ttoaddr</A>(3), <A HREF="ipsec_samesaid.3.html">ipsec_samesaid</A>(3), <A HREF="inet.3.html">inet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>ttosa</I>
+
+are:
+empty input;
+input too small to be a legal SA specifier;
+no
+<B>@</B>
+
+in input;
+unknown protocol prefix;
+conversion error in
+<I>ttoul</I>
+
+or
+<I>ttoaddr</I>.
+
+<P>
+
+Fatal errors in
+<I>satot</I>
+
+are:
+unknown format.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+The restriction of text-to-binary error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The text-to-binary error-reporting convention lends itself
+to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = ttosa( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_send-pr.8.html b/doc/manpage.d/ipsec_send-pr.8.html
new file mode 100644
index 000000000..19026543a
--- /dev/null
+++ b/doc/manpage.d/ipsec_send-pr.8.html
@@ -0,0 +1,427 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of SEND-PR</TITLE>
+</HEAD><BODY>
+<H1>SEND-PR</H1>
+Section: User Commands  (1)<BR>Updated: xVERSIONx<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec send-pr - send problem report (PR) to a central support site
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec send-pr</B>
+
+[
+<I>site</I>
+
+]
+[
+<B>-f</B>
+
+<I>problem-report</I>
+
+]
+[
+<B>-t</B>
+
+<I>mail-address</I>
+
+]
+<BR>
+
+
+[
+<B>-P</B>
+
+]
+[
+<B>-L</B>
+
+]
+[
+<B>-s</B>
+
+<I>severity</I>
+
+]
+[
+<B>-c</B>
+
+<I>address</I>
+
+]
+<BR>
+
+[
+<B>--request-id</B>
+
+]
+[
+<B>-V</B>
+
+]
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<B>ipsec send-pr</B>
+
+is a tool used to submit 
+<I>problem reports </I>
+
+
+(PRs) to a central support site.  In most cases the correct 
+<I>site</I>
+
+will be the default.  This argument indicates the support site which
+is responsible for the category of problem involved.  Some sites may
+use a local address as a default.  
+<I>site</I>
+
+values are defined by using the 
+<B><A HREF="aliases.5.html">aliases</A></B>(5).
+
+<P>
+
+<B>ipsec send-pr</B>
+
+invokes an editor on a problem report template (after trying to fill
+in some fields with reasonable default values).  When you exit the
+editor,
+<B>ipsec send-pr </B>
+
+sends the completed form to the
+<I>Problem Report Management System</I>
+
+(<B>GNATS</B>) at a central support site.  At the support site, the PR
+is assigned a unique number and is stored in the <B>GNATS</B> database
+according to its category and submitter-id.  <B>GNATS</B> automatically
+replies with an acknowledgement, citing the category and the PR
+number.
+<P>
+
+To ensure that a PR is handled promptly, it should contain your (unique)
+<I>submitter-id</I> and one of the available <I>categories</I> to identify the
+problem area.  (Use
+<B>`ipsec send-pr -L'</B>
+
+to see a list of categories.)
+<P>
+
+The
+<B>ipsec send-pr</B>
+
+template at your site should already be customized with your
+submitter-id (running `<B>install-sid</B> <I>submitter-id</I>' to
+accomplish this is part of the installation procedures for
+<B>ipsec</B>send-pr<B>).</B>
+
+If this hasn't been done, see your system administrator for your
+submitter-id, or request one from your support site by invoking
+<B>`ipsec send-pr --request-id'.</B>
+
+If your site does not distinguish between different user sites, or if
+you are not affiliated with the support site, use
+<B>`net'</B>
+
+for this field.
+<P>
+
+The more precise your problem description and the more complete your
+information, the faster your support team can solve your problems.
+<A NAME="lbAE">&nbsp;</A>
+<H2>OPTIONS</H2>
+
+<DL COMPACT>
+<DT><B>-f</B><I> problem-report</I>
+
+<DD>
+specify a file (<I>problem-report</I>) which already contains a
+complete problem report.
+<B>ipsec send-pr</B>
+
+sends the contents of the file without invoking the editor.  If 
+the value for 
+<I>problem-report</I>
+
+is
+<B>`-'</B>,
+
+then
+<B>ipsec send-pr</B>
+
+reads from standard input.
+<DT><B>-s</B><I> severity</I>
+
+<DD>
+Give the problem report the severity
+<I>severity</I>.
+
+<DT><B>-t</B><I> mail-address</I>
+
+<DD>
+Change mail address at the support site for problem reports.  The
+default 
+<I>mail-address</I>
+
+is the address used for the default 
+<I>site</I>.
+
+Use the
+<I>site</I>
+
+argument rather than this option in nearly all cases.
+<DT><B>-c</B><I> address</I>
+
+<DD>
+Put
+<I>address</I>
+
+in the 
+<B>Cc:</B>
+
+header of the message.
+<DT><B>-P</B>
+
+<DD>
+print the form specified by the environment variable 
+<B>PR_FORM </B>
+
+on standard output.  If 
+<B>PR_FORM</B>
+
+is not set, print the standard blank PR template.  No mail is sent.
+<DT><B>-L</B>
+
+<DD>
+print the list of available categories.  No mail is sent.
+<DT><B>--request-id</B>
+
+<DD>
+sends mail to the default support site, or
+<I>site</I>
+
+if specified, with a request for your 
+<I>submitter-id</I>.
+
+If you are
+not affiliated with 
+<I>site</I>,
+
+use a
+<I>submitter-id</I>
+
+of
+<B>net</B>'.
+
+<DT><B>-V</B>
+
+<DD>
+Display the 
+<B>ipsec send-pr</B>
+
+version number.
+</DL>
+<P>
+
+Note: use
+<B>ipsec send-pr</B>
+
+to submit problem reports rather than mailing them directly.  Using
+both the template and
+<B>ipsec send-pr</B>
+
+itself will help ensure all necessary information will reach the
+support site.
+<A NAME="lbAF">&nbsp;</A>
+<H2>ENVIRONMENT</H2>
+
+The environment variable 
+<B>EDITOR</B>
+
+specifies the editor to invoke on the template.
+<BR>
+
+default:
+<B>vi</B>
+
+<P>
+If the environment variable 
+<B>PR_FORM</B>
+
+is set, then its value is used as the file name of the template for
+your problem-report editing session.  You can use this to start with a
+partially completed form (for example, a form with the identification
+fields already completed).
+<A NAME="lbAG">&nbsp;</A>
+<H2>HOW TO FILL OUT A PROBLEM REPORT</H2>
+
+Problem reports have to be in a particular form so that a program can
+easily manage them.  Please remember the following guidelines:
+<DL COMPACT>
+<DT>*<DD>
+describe only 
+<B>one problem</B>
+
+with each problem report.
+<DT>*<DD>
+For follow-up mail, use the same subject line as the one in the automatic
+acknowledgent. It consists of category, PR number and the original synopsis
+line.  This allows the support site to relate several mail messages to a
+particular PR and to record them automatically.
+<DT>*<DD>
+Please try to be as accurate as possible in the subject and/or synopsis line.
+<DT>*<DD>
+The subject and the synopsis line are not confidential.  This is
+because open-bugs lists are compiled from them.  Avoid confidential
+information there.
+</DL>
+<P>
+
+See the GNU 
+<B>Info </B>
+
+file
+<B>send-pr.info</B>
+
+or the document <I>Reporting Problems With send-pr</I>&nbsp;for detailed
+information on reporting problems
+<A NAME="lbAH">&nbsp;</A>
+<H2>HOW TO SUBMIT TEST CASES, CODE, ETC.</H2>
+
+Submit small code samples with the PR.  Contact the support site for
+instructions on submitting larger test cases and problematic source
+code.
+<A NAME="lbAI">&nbsp;</A>
+<H2>FILES</H2>
+
+
+
+/tmp/p$$<TT>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TT>copy of PR used in editing session<BR>
+<BR>
+
+/tmp/pf$$<TT>&nbsp;&nbsp;&nbsp;</TT>copy of empty PR form, for testing purposes<BR>
+<BR>
+
+/tmp/pbad$$<TT>&nbsp;</TT>file for rejected PRs<BR>
+<BR>
+
+@IPSEC_DIR@/send-pr.confscript to customize send-pr.<BR>
+<A NAME="lbAJ">&nbsp;</A>
+<H2>EMACS USER INTERFACE</H2>
+
+An Emacs user interface for 
+<B>send-pr</B>
+
+with completion of field values is part of the 
+<B>send-pr</B>
+
+distribution (invoked with
+<B>M-x send-pr</B>).
+
+See the file
+<B>send-pr.info</B>
+
+or the ASCII file
+<B>INSTALL</B>
+
+in the top level directory of the distribution for configuration and
+installation information.  The Emacs LISP template file is 
+<B>send-pr-el.in</B>
+
+and is installed as
+<B>send-pr.el</B>.
+
+<A NAME="lbAK">&nbsp;</A>
+<H2>INSTALLATION AND CONFIGURATION</H2>
+
+See 
+<B>send-pr.info</B>
+
+or
+<B>INSTALL</B>
+
+for installation instructions.
+<A NAME="lbAL">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<I>Reporting Problems Using send-pr</I>
+
+(also installed as the GNU Info file
+<B>send-pr.info</B>).
+
+<P>
+
+<B><A HREF="http://localhost/cgi-bin/man/man2html?l+gnats">gnats</A></B>(l),
+
+<B><A HREF="query-pr.1.html">query-pr</A></B>(1),
+
+<B><A HREF="edit-pr.1.html">edit-pr</A></B>(1),
+
+<B><A HREF="gnats.8.html">gnats</A></B>(8),
+
+<B><A HREF="queue-pr.8.html">queue-pr</A></B>(8),
+
+<B><A HREF="at-pr.8.html">at-pr</A></B>(8),
+
+<B><A HREF="mkcat.8.html">mkcat</A></B>(8),
+
+<B><A HREF="mkdist.8.html">mkdist</A></B>(8).
+
+<A NAME="lbAM">&nbsp;</A>
+<H2>AUTHORS</H2>
+
+Jeffrey Osier, Brendan Kehoe, Jason Merrill, Heinz G. Seidl (Cygnus
+Support)
+<A NAME="lbAN">&nbsp;</A>
+<H2>COPYING</H2>
+
+Copyright (c) 1992, 1993 Free Software Foundation, Inc.
+<P>
+
+Permission is granted to make and distribute verbatim copies of
+this manual provided the copyright notice and this permission notice
+are preserved on all copies.
+<P>
+
+Permission is granted to copy and distribute modified versions of this
+manual under the conditions for verbatim copying, provided that the
+entire resulting derived work is distributed under the terms of a
+permission notice identical to this one.
+<P>
+
+Permission is granted to copy and distribute translations of this
+manual into another language, under the above conditions for modified
+versions, except that this permission notice may be included in
+translations approved by the Free Software Foundation instead of in
+the original English.
+<P>
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">OPTIONS</A><DD>
+<DT><A HREF="#lbAF">ENVIRONMENT</A><DD>
+<DT><A HREF="#lbAG">HOW TO FILL OUT A PROBLEM REPORT</A><DD>
+<DT><A HREF="#lbAH">HOW TO SUBMIT TEST CASES, CODE, ETC.</A><DD>
+<DT><A HREF="#lbAI">FILES</A><DD>
+<DT><A HREF="#lbAJ">EMACS USER INTERFACE</A><DD>
+<DT><A HREF="#lbAK">INSTALLATION AND CONFIGURATION</A><DD>
+<DT><A HREF="#lbAL">SEE ALSO</A><DD>
+<DT><A HREF="#lbAM">AUTHORS</A><DD>
+<DT><A HREF="#lbAN">COPYING</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_setportof.3.html b/doc/manpage.d/ipsec_setportof.3.html
new file mode 100644
index 000000000..3965ca62d
--- /dev/null
+++ b/doc/manpage.d/ipsec_setportof.3.html
@@ -0,0 +1,143 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_PORTOF</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_PORTOF</H1>
+Section: C Library Functions (3)<BR>Updated: 8 Sept 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec portof - get port field of an ip_address
+<BR>
+
+ipsec setportof - set port field of an ip_address
+<BR>
+
+ipsec sockaddrof - get pointer to internal sockaddr of an ip_address
+<BR>
+
+ipsec sockaddrlenof - get length of internal sockaddr of an ip_address
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>int portof(const ip_address *src);</B>
+
+<BR>
+
+<B>void setportof(int port, ip_address *dst);</B>
+
+<BR>
+
+<B>struct sockaddr *sockaddrof(ip_address *src);</B>
+
+<BR>
+
+<B>size_t sockaddrlenof(const ip_address *src);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+internal type
+<I>ip_address</I>
+
+contains one of the
+<I>sockaddr</I>
+
+types internally.
+<I>Reliance on this feature is discouraged</I>,
+but it may occasionally be necessary.
+These functions provide low-level tools for this purpose.
+<P>
+
+<I>Portof</I>
+
+and
+<I>setportof</I>
+
+respectively read and write the port-number field of the internal
+<I>sockaddr</I>.
+
+The values are in network byte order.
+<P>
+
+<I>Sockaddrof</I>
+
+returns a pointer to the internal
+<I>sockaddr</I>,
+
+for passing to other functions.
+<P>
+
+<I>Sockaddrlenof</I>
+
+reports the size of the internal
+<I>sockaddr</I>,
+
+for use in storage allocation.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_initaddr.3.html">ipsec_initaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+<I>Portof</I>
+
+returns
+<B>-1</B>,
+
+<I>sockaddrof</I>
+
+returns
+<B>NULL</B>,
+
+and
+<I>sockaddrlenof</I>
+
+returns
+<B>0</B>
+
+if an unknown address family is found within the
+<I>ip_address</I>.
+
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+These functions all depend on low-level details of the
+<I>ip_address</I>
+
+type, which are in principle subject to change.
+Avoid using them unless really necessary.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_setup.8.html b/doc/manpage.d/ipsec_setup.8.html
new file mode 100644
index 000000000..7197e2b18
--- /dev/null
+++ b/doc/manpage.d/ipsec_setup.8.html
@@ -0,0 +1,237 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_SETUP</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_SETUP</H1>
+Section: Maintenance Commands (8)<BR>Updated: 23 July 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec setup - control IPsec subsystem
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>setup</B>
+
+[
+<B>--show</B>
+
+|
+<B>--showonly</B>
+
+]
+command
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Setup</I>
+
+controls the FreeS/WAN IPsec subsystem,
+including both the Klips kernel code and the Pluto key-negotiation daemon.
+(It is a synonym for the ``rc'' script for the subsystem;
+the system runs the equivalent of
+<B>ipsec setup start</B>
+
+at boot time,
+and
+<B>ipsec setup stop</B>
+
+at shutdown time, more or less.)
+<P>
+
+The action taken depends on the specific
+<I>command</I>,
+
+and on the contents of the
+<B>config</B>
+
+<B>setup</B>
+
+section of the
+IPsec configuration file (<I>/etc/ipsec.conf</I>,
+
+see
+<I><A HREF="ipsec.conf.5.html">ipsec.conf</A></I>(5)).
+
+Current
+<I>command</I>s
+
+are:
+<DL COMPACT>
+<DT><B>start</B>
+
+<DD>
+start Klips and Pluto,
+including setting up Klips to do crypto operations on the 
+interface(s) specified in the configuration file,
+and (if the configuration file so specifies)
+setting up manually-keyed connections and/or
+asking Pluto to negotiate automatically-keyed connections
+to other security gateways
+<DT><B>stop</B>
+
+<DD>
+shut down Klips and Pluto,
+including tearing down all existing crypto connections
+<DT><B>restart</B>
+
+<DD>
+equivalent to
+<B>stop</B>
+
+followed by
+<B>start</B>
+
+<DT><B>status</B>
+
+<DD>
+report the status of the subsystem;
+normally just reports
+<B>IPsec running</B>
+
+and
+<B>pluto pid </B><I>nnn</I>,
+
+or
+<B>IPsec stopped</B>,
+
+and exits with status 0,
+but will go into more detail (and exit with status 1)
+if something strange is found.
+(An ``illicit'' Pluto is one that does not match the process ID in
+Pluto's lock file;
+an ``orphaned'' Pluto is one with no lock file.)
+</DL>
+<P>
+
+The
+<B>stop</B>
+
+operation tries to clean up properly even if assorted accidents
+have occurred,
+e.g. Pluto having died without removing its lock file.
+If
+<B>stop</B>
+
+discovers that the subsystem is (supposedly) not running,
+it will complain,
+but will do its cleanup anyway before exiting with status 1.
+<P>
+
+Although a number of configuration-file parameters influence
+<I>setup</I>'s
+
+operations, the key one is the
+<B>interfaces</B>
+
+parameter, which must be right or chaos will ensue.
+<P>
+
+The
+<B>--show</B>
+
+and
+<B>--showonly</B>
+
+options cause
+<I>setup</I>
+
+to display the shell commands that it would execute.
+<B>--showonly</B>
+
+suppresses their execution.
+Only
+<B>start</B>,
+
+<B>stop</B>,
+
+and
+<B>restart</B>
+
+commands recognize these flags.
+<A NAME="lbAE">&nbsp;</A>
+<H2>FILES</H2>
+
+
+
+/etc/rc.d/init.d/ipsec<TT>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TT>the script itself<BR>
+<BR>
+
+/etc/init.d/ipsec<TT>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TT>alternate location for the script<BR>
+<BR>
+
+/etc/ipsec.conf<TT>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TT>IPsec configuration file<BR>
+<BR>
+
+/proc/sys/net/ipv4/ip_forward<TT>&nbsp;</TT>forwarding control<BR>
+<BR>
+
+/var/run/ipsec.info<TT>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TT>saved information<BR>
+<BR>
+
+/var/run/pluto.pid<TT>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TT>Pluto lock file<BR>
+<BR>
+
+/var/run/ipsec_setup.pid<TT>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TT>IPsec lock file<BR>
+<A NAME="lbAF">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.conf.5.html">ipsec.conf</A>(5), <A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_manual.8.html">ipsec_manual</A>(8), <A HREF="ipsec_auto.8.html">ipsec_auto</A>(8), <A HREF="route.8.html">route</A>(8)
+<A NAME="lbAG">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+All output from the commands
+<B>start</B>
+
+and
+<B>stop</B>
+
+goes both to standard
+output and to
+<I><A HREF="syslogd.8.html">syslogd</A></I>(8),
+
+via
+<I><A HREF="logger.1.html">logger</A></I>(1).
+
+Selected additional information is logged only to
+<I><A HREF="syslogd.8.html">syslogd</A></I>(8).
+
+<A NAME="lbAH">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org">http://www.freeswan.org</A>&gt;
+by Henry Spencer.
+<A NAME="lbAI">&nbsp;</A>
+<H2>BUGS</H2>
+
+Old versions of
+<I><A HREF="logger.1.html">logger</A></I>(1)
+
+inject spurious extra newlines onto standard output.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">FILES</A><DD>
+<DT><A HREF="#lbAF">SEE ALSO</A><DD>
+<DT><A HREF="#lbAG">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAH">HISTORY</A><DD>
+<DT><A HREF="#lbAI">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_showdefaults.8.html b/doc/manpage.d/ipsec_showdefaults.8.html
new file mode 100644
index 000000000..e1786dc0a
--- /dev/null
+++ b/doc/manpage.d/ipsec_showdefaults.8.html
@@ -0,0 +1,82 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_SHOWDEFAULTS</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_SHOWDEFAULTS</H1>
+Section: Maintenance Commands (8)<BR>Updated: 23 Jan 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec showdefaults - show %defaultroute defaults
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>showdefaults</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Showdefaults</I>
+
+outputs (on standard output) a terse description of the defaults
+used by the
+<B>%defaultroute</B>
+
+facilities in
+<I><A HREF="ipsec_auto.8.html">ipsec_auto</A></I>(8)
+
+and
+<I><A HREF="ipsec_manual.8.html">ipsec_manual</A></I>(8).
+
+<P>
+
+Beware that the exact output format is subject to change.
+<A NAME="lbAE">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Normal exit status is 0.
+If no defaults are available,
+i.e. the
+<B>interfaces</B>
+
+parameter in
+<B>config setup</B>
+
+is not
+<B>%defaultroute</B>,
+
+produces a message on standard error and exits with status 1.
+<A NAME="lbAF">&nbsp;</A>
+<H2>FILES</H2>
+
+/var/run/ipsec.info
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org">http://www.freeswan.org</A>&gt;
+by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAF">FILES</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_showhostkey.8.html b/doc/manpage.d/ipsec_showhostkey.8.html
new file mode 100644
index 000000000..90a16d5ee
--- /dev/null
+++ b/doc/manpage.d/ipsec_showhostkey.8.html
@@ -0,0 +1,269 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_SHOWHOSTKEY</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_SHOWHOSTKEY</H1>
+Section: Maintenance Commands (8)<BR>Updated: 5 March 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec showhostkey - show host's authentication key
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>showhostkey</B>
+
+[
+<B>--key</B>
+
+] [
+<B>--left</B>
+
+] [
+<B>--right</B>
+
+] [
+<B>--txt</B>
+
+gateway
+] [
+<B>--dhclient</B>
+
+] [
+<B>--file</B>
+
+secretfile
+] [
+<B>--id</B>
+
+identity
+]
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Showhostkey</I>
+
+outputs (on standard output) a public key suitable for this host,
+in the format specified,
+using the host key information stored in
+<I>/etc/ipsec.secrets</I>.
+
+In general only the super-user can run this command,
+since only he can read
+<I>ipsec.secrets</I>.
+
+<P>
+
+The
+<B>--txt</B>
+
+option causes the output to be in opportunistic-encryption DNS TXT record
+format,
+with the specified
+<I>gateway</I>
+
+value.
+If information about how the key was generated is available,
+that is provided as a DNS-file comment.
+For example,
+<B>--txt 10.11.12.13</B>
+
+might give (with the key data trimmed for clarity):
+<P>
+
+<PRE>
+  ; RSA 2048 bits   xy.example.com   Sat Apr 15 13:53:22 2000
+      IN TXT  &quot;X-IPsec-Server(10)=10.11.12.13 AQOF8tZ2...+buFuFn/&quot;
+</PRE>
+
+<P>
+
+No name is supplied in the TXT record
+because there are too many possibilities,
+depending on how it will be used.
+If the text string is longer than 255 bytes,
+it is split up into multiple strings (matching the restrictions of
+the DNS TXT binary format).
+If any split is needed, the first split will be at the start of the key:
+this increases the chances that later hand editing will work.
+<P>
+
+The
+<B>--left</B>
+
+and
+<B>--right</B>
+
+options cause the output to be in
+<I><A HREF="ipsec.conf.5.html">ipsec.conf</A></I>(5)
+
+format, as a
+<B>leftrsasigkey</B>
+
+or
+<B>rightrsasigkey</B>
+
+parameter respectively.
+Again, generation information is included if available.
+For example,
+<B>--left</B>
+
+might give (with the key data trimmed down for clarity):
+<P>
+
+<PRE>
+  # RSA 2048 bits   xy.example.com   Sat Apr 15 13:53:22 2000
+  leftrsasigkey=0sAQOF8tZ2...+buFuFn/
+</PRE>
+
+<P>
+
+The
+<B>--dhclient</B>
+
+option cause the output to be suitable for inclusion in
+<I><A HREF="dhclient.conf.5.html">dhclient.conf</A></I>(5)
+
+as part of configuring WAVEsec.
+See &lt;<A HREF="http://www.wavesec.org">http://www.wavesec.org</A>&gt;.
+<P>
+
+If
+<B>--key</B>
+
+is specified,
+the output format is the text form of a DNS KEY record;
+the host name is the one included in the key information
+(or, if that is not available,
+the output of
+<B>hostname&nbsp;--fqdn</B>),
+
+with a
+<B>.</B>
+
+appended.
+Again, generation information is included if available.
+For example (with the key data trimmed down for clarity):
+<P>
+
+<PRE>
+  ; RSA 2048 bits   xy.example.com   Sat Apr 15 13:53:22 2000
+  xy.example.com.   IN   KEY   0x4200 4 1 AQOF8tZ2...+buFuFn/
+</PRE>
+
+<P>
+
+Normally, the default key for this host
+(the one with no host identities specified for it) is the one extracted.
+The
+<B>--id</B>
+
+option overrides this,
+causing extraction of the key labeled with the specified
+<I>identity</I>,
+
+if any.
+The specified
+<I>identity</I>
+
+must
+<I>exactly</I>
+
+match the identity in the file;
+in particular, the comparison is case-sensitive.
+<P>
+
+The
+<B>--file</B>
+
+option overrides the default for where the key information should be
+found, and takes it from the specified
+<I>secretfile</I>.
+
+<A NAME="lbAE">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+A complaint about ``no pubkey line found'' indicates that the
+host has a key but it was generated with an old version of FreeS/WAN
+and does not contain the information that
+<I>showhostkey</I>
+
+needs.
+<A NAME="lbAF">&nbsp;</A>
+<H2>FILES</H2>
+
+/etc/ipsec.secrets
+<A NAME="lbAG">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.secrets.5.html">ipsec.secrets</A>(5), <A HREF="ipsec.conf.5.html">ipsec.conf</A>(5), <A HREF="ipsec_rsasigkey.8.html">ipsec_rsasigkey</A>(8)
+<A NAME="lbAH">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org">http://www.freeswan.org</A>&gt;
+by Henry Spencer.
+<A NAME="lbAI">&nbsp;</A>
+<H2>BUGS</H2>
+
+Arguably,
+rather than just reporting the no-IN-KEY-line-found problem,
+<I>showhostkey</I>
+
+should be smart enough to run the existing key through
+<I>rsasigkey</I>
+
+with the
+<B>--oldkey</B>
+
+option, to generate a suitable output line.
+<P>
+
+The need to specify the gateway address (etc.) for
+<B>--txt</B>
+
+is annoying, but there is no good way to determine it automatically.
+<P>
+
+There should be a way to specify the priority value for TXT records;
+currently it is hardwired to
+<B>10</B>.
+
+<P>
+
+The
+<B>--id</B>
+
+option assumes that the
+<I>identity</I>
+
+appears on the same line as the
+<B>:&nbsp;RSA&nbsp;{</B>
+
+that begins the key proper.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAF">FILES</A><DD>
+<DT><A HREF="#lbAG">SEE ALSO</A><DD>
+<DT><A HREF="#lbAH">HISTORY</A><DD>
+<DT><A HREF="#lbAI">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_showpolicy.8.html b/doc/manpage.d/ipsec_showpolicy.8.html
new file mode 100644
index 000000000..470c40879
--- /dev/null
+++ b/doc/manpage.d/ipsec_showpolicy.8.html
@@ -0,0 +1,88 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_SHOWPOLICY</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_SHOWPOLICY</H1>
+Section: Maintenance Commands (8)<BR>Updated: 7 May 2003<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec showpolicy - dump policy of socket found as stdin
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<P>
+
+<B>ipsec</B>
+
+<B>showpolicy</B>
+
+<P>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>showpolicy</I>
+
+calls the 
+<I><A HREF="ipsec_policy_lookup.3.html">ipsec_policy_lookup</A></I>(3)
+
+function on the file description which is its stdin.
+<P>
+
+It then dumps the resulting query in a human readable form.
+<P>
+
+This is a test program. One might run it from inetd, via:
+<DL COMPACT>
+<DT>discard stream tcp nowait nobody /usr/local/libexec/ipsec/showpolicy showpolicy<DD>
+</DL>
+<A NAME="lbAE">&nbsp;</A>
+<H2>FILES</H2>
+
+/var/run/ipsecpolicy.ctl
+<A NAME="lbAF">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_policy_query.3.html">ipsec_policy_query</A>(3), <A HREF="ipsec_pluto.8.html">ipsec_pluto</A>(8)
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Michael Richardson
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">FILES</A><DD>
+<DT><A HREF="#lbAF">SEE ALSO</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_sockaddrlenof.3.html b/doc/manpage.d/ipsec_sockaddrlenof.3.html
new file mode 100644
index 000000000..3965ca62d
--- /dev/null
+++ b/doc/manpage.d/ipsec_sockaddrlenof.3.html
@@ -0,0 +1,143 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_PORTOF</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_PORTOF</H1>
+Section: C Library Functions (3)<BR>Updated: 8 Sept 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec portof - get port field of an ip_address
+<BR>
+
+ipsec setportof - set port field of an ip_address
+<BR>
+
+ipsec sockaddrof - get pointer to internal sockaddr of an ip_address
+<BR>
+
+ipsec sockaddrlenof - get length of internal sockaddr of an ip_address
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>int portof(const ip_address *src);</B>
+
+<BR>
+
+<B>void setportof(int port, ip_address *dst);</B>
+
+<BR>
+
+<B>struct sockaddr *sockaddrof(ip_address *src);</B>
+
+<BR>
+
+<B>size_t sockaddrlenof(const ip_address *src);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+internal type
+<I>ip_address</I>
+
+contains one of the
+<I>sockaddr</I>
+
+types internally.
+<I>Reliance on this feature is discouraged</I>,
+but it may occasionally be necessary.
+These functions provide low-level tools for this purpose.
+<P>
+
+<I>Portof</I>
+
+and
+<I>setportof</I>
+
+respectively read and write the port-number field of the internal
+<I>sockaddr</I>.
+
+The values are in network byte order.
+<P>
+
+<I>Sockaddrof</I>
+
+returns a pointer to the internal
+<I>sockaddr</I>,
+
+for passing to other functions.
+<P>
+
+<I>Sockaddrlenof</I>
+
+reports the size of the internal
+<I>sockaddr</I>,
+
+for use in storage allocation.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_initaddr.3.html">ipsec_initaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+<I>Portof</I>
+
+returns
+<B>-1</B>,
+
+<I>sockaddrof</I>
+
+returns
+<B>NULL</B>,
+
+and
+<I>sockaddrlenof</I>
+
+returns
+<B>0</B>
+
+if an unknown address family is found within the
+<I>ip_address</I>.
+
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+These functions all depend on low-level details of the
+<I>ip_address</I>
+
+type, which are in principle subject to change.
+Avoid using them unless really necessary.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_sockaddrof.3.html b/doc/manpage.d/ipsec_sockaddrof.3.html
new file mode 100644
index 000000000..3965ca62d
--- /dev/null
+++ b/doc/manpage.d/ipsec_sockaddrof.3.html
@@ -0,0 +1,143 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_PORTOF</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_PORTOF</H1>
+Section: C Library Functions (3)<BR>Updated: 8 Sept 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec portof - get port field of an ip_address
+<BR>
+
+ipsec setportof - set port field of an ip_address
+<BR>
+
+ipsec sockaddrof - get pointer to internal sockaddr of an ip_address
+<BR>
+
+ipsec sockaddrlenof - get length of internal sockaddr of an ip_address
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>int portof(const ip_address *src);</B>
+
+<BR>
+
+<B>void setportof(int port, ip_address *dst);</B>
+
+<BR>
+
+<B>struct sockaddr *sockaddrof(ip_address *src);</B>
+
+<BR>
+
+<B>size_t sockaddrlenof(const ip_address *src);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+internal type
+<I>ip_address</I>
+
+contains one of the
+<I>sockaddr</I>
+
+types internally.
+<I>Reliance on this feature is discouraged</I>,
+but it may occasionally be necessary.
+These functions provide low-level tools for this purpose.
+<P>
+
+<I>Portof</I>
+
+and
+<I>setportof</I>
+
+respectively read and write the port-number field of the internal
+<I>sockaddr</I>.
+
+The values are in network byte order.
+<P>
+
+<I>Sockaddrof</I>
+
+returns a pointer to the internal
+<I>sockaddr</I>,
+
+for passing to other functions.
+<P>
+
+<I>Sockaddrlenof</I>
+
+reports the size of the internal
+<I>sockaddr</I>,
+
+for use in storage allocation.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_initaddr.3.html">ipsec_initaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+<I>Portof</I>
+
+returns
+<B>-1</B>,
+
+<I>sockaddrof</I>
+
+returns
+<B>NULL</B>,
+
+and
+<I>sockaddrlenof</I>
+
+returns
+<B>0</B>
+
+if an unknown address family is found within the
+<I>ip_address</I>.
+
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+These functions all depend on low-level details of the
+<I>ip_address</I>
+
+type, which are in principle subject to change.
+Avoid using them unless really necessary.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_spi.5.html b/doc/manpage.d/ipsec_spi.5.html
new file mode 100644
index 000000000..b1cf89033
--- /dev/null
+++ b/doc/manpage.d/ipsec_spi.5.html
@@ -0,0 +1,305 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_SPI</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_SPI</H1>
+Section: File Formats (5)<BR>Updated: 26 Jun 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec_spi - list IPSEC Security Associations
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>spi</B>
+
+<P>
+
+<B>cat</B>
+
+<B>/proc/net/ipsec_spi</B>
+
+<P>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>/proc/net/ipsec_spi</I>
+
+is a read-only file that lists the current IPSEC Security Associations.
+A Security Association (SA) is a transform through which packet contents
+are to be processed before being forwarded.  A transform can be an
+IPv4-in-IPv4 or IPv6-in-IPv6 encapsulation, an IPSEC Authentication Header (authentication
+with no encryption), or an IPSEC Encapsulation Security Payload
+(encryption, possibly including authentication).
+<P>
+
+When a packet is passed from a higher networking layer through an IPSEC
+virtual interface, a search in the extended routing table (see
+<I><A HREF="ipsec_eroute.5.html">ipsec_eroute</A></I>(5))
+
+yields
+a IP protocol number
+,
+a Security Parameters Index (SPI)
+and
+an effective destination address
+When an IPSEC packet arrives from the network,
+its ostensible destination, an SPI and an IP protocol
+specified by its outermost IPSEC header are used.
+The destination/SPI/protocol combination is used to select a relevant SA.
+(See
+<I><A HREF="ipsec_spigrp.5.html">ipsec_spigrp</A></I>(5)
+
+for discussion of how multiple transforms are combined.)
+<P>
+
+An
+<I>spi ,</I>
+
+<I>proto, </I>
+
+<I>daddr</I>
+
+and
+<I>address_family</I>
+
+arguments specify an SAID.
+<I>Proto</I>
+
+is an ASCII string, &quot;ah&quot;, &quot;esp&quot;, &quot;comp&quot; or &quot;tun&quot;, specifying the IP protocol.
+<I>Spi</I>
+
+is a number, preceded by '.' indicating hexadecimal and IPv4 or by ':' indicating hexadecimal and IPv6,
+where each hexadecimal digit represents 4 bits,
+between
+<B>0x100</B>
+
+and
+<B>0xffffffff</B>;
+
+values from
+<B>0x0</B>
+
+to
+<B>0xff</B>
+
+are reserved.
+<I>Daddr</I>
+
+is a dotted-decimal IPv4 destination address or a coloned hex IPv6 destination address.
+<P>
+
+An
+<I>SAID</I>
+
+combines the three parameters above, such as: &quot;<A HREF="mailto:tun.101@1.2.3.4">tun.101@1.2.3.4</A>&quot; for IPv4 or &quot;tun:<A HREF="mailto:101@3049">101@3049</A>:1::1&quot; for IPv6
+<P>
+
+A table entry consists of:
+<DL COMPACT>
+<DT>+<DD>
+<B>SAID</B>
+
+<DT>+<DD>
+&lt;transform name (proto,encalg,authalg)&gt;:
+<DT>+<DD>
+direction (dir=)
+<DT>+<DD>
+source address (src=)
+<DT>+<DD>
+source and destination addresses and masks for inner header policy check
+addresses (policy=), as dotted-quads or coloned hex, separated by '-&gt;',
+for IPv4-in-IPv4 or IPv6-in-IPv6 SAs only
+<DT>+<DD>
+initialisation vector length and value (iv_bits=, iv=) if non-zero
+<DT>+<DD>
+out-of-order window size, number of out-of-order errors, sequence
+number, recently received packet bitmask, maximum difference between
+sequence numbers (ooowin=, ooo_errs=, seq=, bit=, max_seq_diff=) if SA
+is AH or ESP and if individual items are non-zero
+<DT>+<DD>
+extra flags (flags=) if any are set
+<DT>+<DD>
+authenticator length in bits (alen=) if non-zero
+<DT>+<DD>
+authentication key length in bits (aklen=) if non-zero
+<DT>+<DD>
+authentication errors (auth_errs=) if non-zero
+<DT>+<DD>
+encryption key length in bits (eklen=) if non-zero
+<DT>+<DD>
+encryption size errors (encr_size_errs=) if non-zero
+<DT>+<DD>
+encryption padding error warnings (encr_pad_errs=) if non-zero
+<DT>+<DD>
+lifetimes legend, c=Current status, s=Soft limit when exceeded will
+initiate rekeying, h=Hard limit will cause termination of SA (life(c,s,h)=)
+<DT>+<DD>
+number of connections to which the SA is allocated (c), that will cause a
+rekey (s), that will cause an expiry (h) (alloc=), if any value is non-zero
+<DT>+<DD>
+number of bytes processesd by this SA (c), that will cause a rekey (s), that
+will cause an expiry (h) (bytes=), if any value is non-zero
+<DT>+<DD>
+time since the SA was added (c), until rekey (s), until expiry (h), in seconds (add=)
+<DT>+<DD>
+time since the SA was first used (c), until rekey (s), until expiry (h), in seconds (used=),
+if any value is non-zero
+<DT>+<DD>
+number of packets processesd by this SA (c), that will cause a rekey (s), that
+will cause an expiry (h) (packets=), if any value is non-zero
+<DT>+<DD>
+time since the last packet was processed, in seconds (idle=), if SA has
+been used
+<DT><DD>
+average compression ratio (ratio=)
+</DL>
+<A NAME="lbAE">&nbsp;</A>
+<H2>EXAMPLES</H2>
+
+<B><A HREF="mailto:tun.12a@192.168.43.1">tun.12a@192.168.43.1</A> IPIP: dir=out src=192.168.43.2</B>
+
+<BR>
+
+<B>      life(c,s,h)=bytes(14073,0,0)add(269,0,0)</B>
+
+<BR>
+
+<B>      use(149,0,0)packets(14,0,0)</B>
+
+<BR>
+
+<B>      idle=23</B>
+
+<P>
+
+is an outbound IPv4-in-IPv4 (protocol 4) tunnel-mode SA set up between machines
+192.168.43.2 and 192.168.43.1 with an SPI of 12a in hexadecimal that has
+passed about 14 kilobytes of traffic in 14 packets since it was created,
+269 seconds ago, first used 149 seconds ago and has been idle for 23
+seconds.
+<P>
+
+<B>esp:<A HREF="mailto:9a35fc02@3049">9a35fc02@3049</A>:1::1 ESP_3DES_HMAC_MD5:</B>
+
+<BR>
+
+<B>      dir=in src=<A HREF="mailto:9a35fc02@3049">9a35fc02@3049</A>:1::2</B>
+
+<BR>
+
+<B>      ooowin=32 seq=7149 bit=0xffffffff</B>
+
+<BR>
+
+<B>      alen=128 aklen=128 eklen=192</B>
+
+<BR>
+
+<B>      life(c,s,h)=bytes(1222304,0,0)add(4593,0,0)</B>
+
+<BR>
+
+<B>      use(3858,0,0)packets(7149,0,0)</B>
+
+<BR>
+
+<B>      idle=23</B>
+
+<P>
+
+is an inbound Encapsulating Security Payload (protocol 50) SA on machine
+3049:1::1 with an SPI of 9a35fc02 that uses 3DES as the encryption
+cipher, HMAC MD5 as the authentication algorithm, an out-of-order
+window of 32 packets, a present sequence number of 7149, every one of
+the last 32 sequence numbers was received, the authenticator length and
+keys is 128 bits, the encryption key is 192 bits (actually 168 for 3DES
+since 1 of 8 bits is a parity bit), has passed 1.2 Mbytes of data in
+7149 packets, was added 4593 seconds ago, first used
+3858 seconds ago and has been idle for 23 seconds.
+<P>
+
+<A NAME="lbAF">&nbsp;</A>
+<H2>FILES</H2>
+
+/proc/net/ipsec_spi, /usr/local/bin/ipsec
+<A NAME="lbAG">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_manual.8.html">ipsec_manual</A>(8), <A HREF="ipsec_tncfg.5.html">ipsec_tncfg</A>(5), <A HREF="ipsec_eroute.5.html">ipsec_eroute</A>(5),
+<A HREF="ipsec_spigrp.5.html">ipsec_spigrp</A>(5), <A HREF="ipsec_klipsdebug.5.html">ipsec_klipsdebug</A>(5), <A HREF="ipsec_spi.8.html">ipsec_spi</A>(8), <A HREF="ipsec_version.5.html">ipsec_version</A>(5),
+<A HREF="ipsec_pf_key.5.html">ipsec_pf_key</A>(5)
+<A NAME="lbAH">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Richard Guy Briggs.
+<A NAME="lbAI">&nbsp;</A>
+<H2>BUGS</H2>
+
+The add and use times are awkward, displayed in seconds since machine
+start.  It would be better to display them in seconds before now for
+human readability.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">EXAMPLES</A><DD>
+<DT><A HREF="#lbAF">FILES</A><DD>
+<DT><A HREF="#lbAG">SEE ALSO</A><DD>
+<DT><A HREF="#lbAH">HISTORY</A><DD>
+<DT><A HREF="#lbAI">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_spi.8.html b/doc/manpage.d/ipsec_spi.8.html
new file mode 100644
index 000000000..a40d06d9b
--- /dev/null
+++ b/doc/manpage.d/ipsec_spi.8.html
@@ -0,0 +1,790 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_SPI</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_SPI</H1>
+Section: Maintenance Commands (8)<BR>Updated: 23 Oct 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec spi - manage IPSEC Security Associations
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<BR>
+
+Note: In the following,
+<BR>
+
+<B>&lt;SA&gt;</B>
+
+means:
+<B>--af</B>
+
+(inet | inet6)
+<B>--edst</B>
+
+daddr
+<B>--spi</B>
+
+spi
+<B>--proto</B>
+
+proto OR 
+<B>--said</B>
+
+said,
+<BR>
+
+<B>&lt;life&gt;</B>
+
+means:
+<B>--life</B>
+
+(soft | hard)-(allocations | bytes | addtime | usetime | packets)=value[,...]
+<P>
+
+<B>ipsec</B>
+
+<B>spi</B>
+
+<P>
+
+<B>ipsec</B>
+
+<B>spi</B>
+
+<B>&lt;SA&gt;</B>
+
+<B>--src</B>
+
+src
+<B>--ah</B>
+
+<B>hmac-md5-96</B>|<B>hmac-sha1-96</B>
+
+[
+<B>--replay_window</B>
+
+replayw ]
+[
+<B>&lt;life&gt;</B>
+
+]
+<B>--authkey</B>
+
+akey
+<P>
+
+<B>ipsec</B>
+
+<B>spi</B>
+
+<B>&lt;SA&gt;</B>
+
+<B>--src</B>
+
+src
+<B>--esp</B>
+
+<B>3des</B>
+
+[
+<B>--replay_window</B>
+
+replayw ]
+[
+<B>&lt;life&gt;</B>
+
+]
+<B>--enckey</B>
+
+ekey
+<P>
+
+<B>ipsec</B>
+
+<B>spi</B>
+
+<B>&lt;SA&gt;</B>
+
+<B>--src</B>
+
+src
+<B>--esp</B>
+
+<B>3des-md5-96</B>|<B>3des-sha1-96</B>
+
+[
+<B>--replay_window</B>
+
+replayw ]
+[
+<B>&lt;life&gt;</B>
+
+]
+<B>--enckey</B>
+
+ekey
+<B>--authkey</B>
+
+akey
+<P>
+
+<B>ipsec</B>
+
+<B>spi</B>
+
+<B>&lt;SA&gt;</B>
+
+<B>--src</B>
+
+src
+<B>--comp</B>
+
+<B>deflate</B>
+
+<P>
+
+<B>ipsec</B>
+
+<B>spi</B>
+
+<B>&lt;SA&gt;</B>
+
+<B>--ip4</B>
+
+<B>--src</B>
+
+encap-src
+<B>--dst</B>
+
+encap-dst
+<P>
+
+<B>ipsec</B>
+
+<B>spi</B>
+
+<B>&lt;SA&gt;</B>
+
+<B>--ip6</B>
+
+<B>--src</B>
+
+encap-src
+<B>--dst</B>
+
+encap-dst
+<P>
+
+<B>ipsec</B>
+
+<B>spi</B>
+
+<B>&lt;SA&gt;</B>
+
+<B>--del</B>
+
+<P>
+
+<B>ipsec</B>
+
+<B>spi</B>
+
+<B>--help</B>
+
+<P>
+
+<B>ipsec</B>
+
+<B>spi</B>
+
+<B>--version</B>
+
+<P>
+
+<B>ipsec</B>
+
+<B>spi</B>
+
+<B>--clear</B>
+
+<P>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Spi</I>
+
+creates and deletes IPSEC Security Associations.
+A Security Association (SA) is a transform through which packet
+contents are to be processed before being forwarded.
+A transform can be an IPv4-in-IPv4 or an IPv6-in-IPv6 encapsulation,
+an IPSEC Authentication Header (authentication with no encryption),
+or an IPSEC Encapsulation Security Payload (encryption, possibly
+including authentication).
+<P>
+
+When a packet is passed from a higher networking layer
+through an IPSEC virtual interface,
+a search in the extended routing table (see
+<I><A HREF="ipsec_eroute.8.html">ipsec_eroute</A></I>(8))
+
+yields an effective destination address, a
+Security Parameters Index (SPI) and a IP protocol number.
+When an IPSEC packet arrives from the network,
+its ostensible destination, an SPI and an IP protocol
+specified by its outermost IPSEC header are used.
+The destination/SPI/protocol combination is used to select a relevant SA.
+(See
+<I><A HREF="ipsec_spigrp.8.html">ipsec_spigrp</A></I>(8)
+
+for discussion of how multiple transforms are combined.)
+<P>
+
+The
+<I>af</I>,
+
+<I>daddr</I>,
+
+<I>spi</I>
+
+and
+<I>proto</I>
+
+arguments specify the SA to be created or deleted.
+<I>af</I>
+
+is the address family (inet for IPv4, inet6 for IPv6).
+<I>Daddr</I>
+
+is a destination address
+in dotted-decimal notation for IPv4 
+or in a coloned hex notation for IPv6.
+<I>Spi</I>
+
+is a number, preceded by '0x' for hexadecimal,
+between
+<B>0x100</B>
+
+and
+<B>0xffffffff</B>;
+
+values from
+<B>0x0</B>
+
+to
+<B>0xff</B>
+
+are reserved.
+<I>Proto</I>
+
+is an ASCII string, &quot;ah&quot;, &quot;esp&quot;, &quot;comp&quot; or &quot;tun&quot;, specifying the IP protocol.
+The protocol must agree with the algorithm selected.
+<P>
+
+Alternatively, the
+<I>said</I>
+
+argument can also specify an SA to be created or deleted.
+<I>Said</I>
+
+combines the three parameters above, such as: &quot;<A HREF="mailto:tun.101@1.2.3.4">tun.101@1.2.3.4</A>&quot; or &quot;tun:101@1:2::3:4&quot;,
+where the address family is specified by &quot;.&quot; for IPv4 and &quot;:&quot; for IPv6. The address
+family indicators substitute the &quot;0x&quot; for hexadecimal.
+<P>
+
+The source address,
+<I>src</I>,
+
+must also be provided for the inbound policy check to
+function.  The source address does not need to be included if inbound
+policy checking has been disabled.
+<P>
+
+Keys vectors must be entered as hexadecimal or base64 numbers.
+They should be cryptographically strong random numbers.
+<P>
+
+All hexadecimal numbers are entered as strings of hexadecimal digits
+(0-9 and a-f), without spaces, preceded by '0x', where each hexadecimal
+digit represents 4 bits.
+All base64 numbers are entered as strings of base64 digits
+<BR>&nbsp;(0-9,&nbsp;A-Z,&nbsp;a-z,&nbsp;'+'&nbsp;and&nbsp;'/'),&nbsp;without&nbsp;spaces,&nbsp;preceded&nbsp;by&nbsp;'0s',
+where each hexadecimal digit represents 6 bits and '=' is used for padding.
+<P>
+
+The deletion of an SA which has been grouped will result in the entire chain
+being deleted.
+<P>
+
+The form with no additional arguments lists the contents of
+/proc/net/ipsec_spi.  The format of /proc/net/ipsec_spi is discussed in
+<A HREF="ipsec_spi.5.html">ipsec_spi</A>(5).
+<P>
+
+The lifetime severity of
+<B>soft</B>
+
+sets a limit when the key management daemons are asked to rekey the SA.
+The lifetime severity of
+<B>hard</B>
+
+sets a limit when the SA must expire.
+The lifetime type
+<B>allocations</B>
+
+tells the system when to expire the SA because it is being shared by too many
+eroutes (not currently used).  The lifetime type of
+<B>bytes</B>
+
+tells the system to expire the SA after a certain number of bytes have been
+processed with that SA.  The lifetime type of
+<B>addtime</B>
+
+tells the system to expire the SA a certain number of seconds after the SA was
+installed.  The lifetime type of
+<B>usetime</B>
+
+tells the system to expire the SA a certain number of seconds after that SA has
+processed its first packet.  The lifetime type of
+<B>packets</B>
+
+tells the system to expire the SA after a certain number of packets have been
+processed with that SA.
+<A NAME="lbAE">&nbsp;</A>
+<H2>OPTIONS</H2>
+
+<DL COMPACT>
+<DT><B>--af</B>
+
+<DD>
+specifies the address family (inet for IPv4, inet6 for IPv6)
+<DT><B>--edst</B>
+
+<DD>
+specifies the effective destination
+<I>daddr</I>
+
+of the Security Association
+<DT><B>--spi</B>
+
+<DD>
+specifies the Security Parameters Index
+<I>spi</I>
+
+of the Security Association
+<DT><B>--proto</B>
+
+<DD>
+specifies the IP protocol
+<I>proto</I>
+
+of the Security Association
+<DT><B>--said</B>
+
+<DD>
+specifies the Security Association in monolithic format
+<DT><B>--ah</B>
+
+<DD>
+add an SA for an IPSEC Authentication Header,
+specified by the following transform identifier
+(<B>hmac-md5-96</B>
+
+or
+<B>hmac-sha1-96</B>)
+
+(RFC2402, obsoletes RFC1826)
+<DT><B>hmac-md5-96</B>
+
+<DD>
+transform following the HMAC and MD5 standards,
+using a 128-bit
+<I>key</I>
+
+to produce a 96-bit authenticator (RFC2403)
+<DT><B>hmac-sha1-96</B>
+
+<DD>
+transform following the HMAC and SHA1 standards,
+using a 160-bit
+<I>key</I>
+
+to produce a 96-bit authenticator (RFC2404)
+<DT><B>--esp</B>
+
+<DD>
+add an SA for an IPSEC Encapsulation Security Payload,
+specified by the following
+transform identifier (<B>3des</B>,
+
+or
+<B>3des-md5-96</B>)
+
+(RFC2406, obsoletes RFC1827)
+<DT><B>3des</B>
+
+<DD>
+encryption transform following the Triple-DES standard in
+Cipher-Block-Chaining mode using a 64-bit
+<I>iv</I>
+
+(internally generated) and a 192-bit 3DES
+<I>ekey</I>
+
+(RFC2451)
+<DT><B>3des-md5-96</B>
+
+<DD>
+encryption transform following the Triple-DES standard in
+Cipher-Block-Chaining mode with authentication provided by
+HMAC and MD5
+(96-bit authenticator),
+using a 64-bit
+<I>iv</I>
+
+(internally generated), a 192-bit 3DES
+<I>ekey</I>
+
+and a 128-bit HMAC-MD5
+<I>akey</I>
+
+(RFC2451, RFC2403)
+<DT><B>3des-sha1-96</B>
+
+<DD>
+encryption transform following the Triple-DES standard in
+Cipher-Block-Chaining mode with authentication provided by
+HMAC and SHA1
+(96-bit authenticator),
+using a 64-bit
+<I>iv</I>
+
+(internally generated), a 192-bit 3DES
+<I>ekey</I>
+
+and a 160-bit HMAC-SHA1
+<I>akey</I>
+
+(RFC2451, RFC2404)
+<DT><B>--replay_window</B> replayw
+
+<DD>
+sets the replay window size; valid values are decimal, 1 to 64
+<DT><B>--life</B> life_param[,life_param]
+
+<DD>
+sets the lifetime expiry; the format of
+<B>life_param</B>
+
+consists of a comma-separated list of lifetime specifications without spaces;
+a lifetime specification is comprised of a severity of
+<B>soft</B> or <B>hard</B>
+
+followed by a '-', followed by a lifetime type of
+<B>allocations</B>, <B>bytes</B>, <B>addtime</B>, <B>usetime</B> or <B>packets</B>
+
+followed by an '=' and finally by a value
+<DT><B>--comp</B>
+
+<DD>
+add an SA for IPSEC IP Compression,
+specified by the following
+transform identifier (<B>deflate</B>)
+
+(RFC2393)
+<DT><B>deflate</B>
+
+<DD>
+compression transform following the patent-free Deflate compression algorithm
+(RFC2394)
+<DT><B>--ip4</B>
+
+<DD>
+add an SA for an IPv4-in-IPv4
+tunnel from
+<I>encap-src</I>
+
+to
+<I>encap-dst</I>
+
+<DT><B>--ip6</B>
+
+<DD>
+add an SA for an IPv6-in-IPv6
+tunnel from
+<I>encap-src</I>
+
+to
+<I>encap-dst</I>
+
+<DT><B>--src</B>
+
+<DD>
+specify the source end of an IP-in-IP tunnel from
+<I>encap-src</I>
+
+to
+<I>encap-dst</I>
+
+and also specifies the source address of the Security Association to be
+used in inbound policy checking and must be the same address
+family as
+<I>af</I>
+
+and
+<I>edst</I>
+
+<DT><B>--dst</B>
+
+<DD>
+specify the destination end of an IP-in-IP tunnel from
+<I>encap-src</I>
+
+to
+<I>encap-dst</I>
+
+<DT><B>--del</B>
+
+<DD>
+delete the specified SA
+<DT><B>--clear</B>
+
+<DD>
+clears the table of
+<B>SA</B>s
+
+<DT><B>--help</B>
+
+<DD>
+display synopsis
+<DT><B>--version</B>
+
+<DD>
+display version information
+</DL>
+<A NAME="lbAF">&nbsp;</A>
+<H2>EXAMPLES</H2>
+
+To keep line lengths down and reduce clutter,
+some of the long keys in these examples have been abbreviated
+by replacing part of their text with
+``<I>...</I>''.
+
+Keys used when the programs are actually run must,
+of course, be the full length required for the particular algorithm.
+<P>
+
+<B>ipsec spi --af inet --edst gw2 --spi 0x125 --proto esp \</B>
+
+<BR>
+
+<B>   --src gw1 \</B>
+
+<BR>
+
+<B>   --esp 3des-md5-96 \</B>
+
+<BR>
+
+<B>&nbsp;&nbsp;&nbsp;--enckey&nbsp;0x6630</B><I>...</I><B>97ce&nbsp;\</B>
+
+<BR>
+
+<B>   --authkey 0x9941</B><I>...</I><B>71df</B>
+
+<P>
+
+sets up an SA from
+<B>gw1</B>
+
+to
+<B>gw2</B>
+
+with an SPI of 
+<B>0x125</B>
+
+and protocol
+<B>ESP</B>
+
+(50) using
+<B>3DES</B>
+
+encryption with integral
+<B>MD5-96</B>
+
+authentication transform, using an encryption key of
+<B>0x6630</B><I>...</I><B>97ce</B>
+
+and an authentication key of
+<B>0x9941</B><I>...</I><B>71df</B>
+
+(see note above about abbreviated keys).
+<P>
+
+<B>ipsec spi --af inet6 --edst 3049:9::9000:3100 --spi 0x150 --proto ah \</B>
+
+<BR>
+
+<B>   --src 3049:9::9000:3101 \</B>
+
+<BR>
+
+<B>   --ah hmac-md5-96 \</B>
+
+<BR>
+
+<B>&nbsp;&nbsp;&nbsp;--authkey&nbsp;0x1234</B><I>...</I><B>2eda&nbsp;\</B>
+
+<P>
+
+sets up an SA from
+<B>3049:9::9000:3101</B>
+
+to
+<B>3049:9::9000:3100</B>
+
+with an SPI of 
+<B>0x150</B>
+
+and protocol
+<B>AH</B>
+
+(50) using
+<B>MD5-96</B>
+
+authentication transform, using an authentication key of
+<B>0x1234</B><I>...</I><B>2eda</B>
+
+(see note above about abbreviated keys).
+<P>
+
+<B>ipsec spi --said <A HREF="mailto:tun.987@192.168.100.100">tun.987@192.168.100.100</A> --del </B>
+
+<P>
+
+deletes an SA to
+<B>192.168.100.100</B>
+
+with an SPI of 
+<B>0x987</B>
+
+and protocol
+<B>IPv4-in-IPv4</B>
+
+(4).
+<P>
+
+<B>ipsec spi --said tun:<A HREF="mailto:500@3049">500@3049</A>:9::1000:1 --del </B>
+
+<P>
+
+deletes an SA to
+<B>3049:9::1000:1</B>
+
+with an SPI of 
+<B>0x500</B>
+
+and protocol
+<B>IPv6-in-IPv6</B>
+
+(4).
+<P>
+
+<A NAME="lbAG">&nbsp;</A>
+<H2>FILES</H2>
+
+/proc/net/ipsec_spi, /usr/local/bin/ipsec
+<A NAME="lbAH">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_manual.8.html">ipsec_manual</A>(8), <A HREF="ipsec_tncfg.8.html">ipsec_tncfg</A>(8), <A HREF="ipsec_eroute.8.html">ipsec_eroute</A>(8),
+<A HREF="ipsec_spigrp.8.html">ipsec_spigrp</A>(8), <A HREF="ipsec_klipsdebug.8.html">ipsec_klipsdebug</A>(8), <A HREF="ipsec_spi.5.html">ipsec_spi</A>(5)
+<A NAME="lbAI">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Richard Guy Briggs.
+<A NAME="lbAJ">&nbsp;</A>
+<H2>BUGS</H2>
+
+The syntax is messy and the transform naming needs work.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">OPTIONS</A><DD>
+<DT><A HREF="#lbAF">EXAMPLES</A><DD>
+<DT><A HREF="#lbAG">FILES</A><DD>
+<DT><A HREF="#lbAH">SEE ALSO</A><DD>
+<DT><A HREF="#lbAI">HISTORY</A><DD>
+<DT><A HREF="#lbAJ">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_spigrp.5.html b/doc/manpage.d/ipsec_spigrp.5.html
new file mode 100644
index 000000000..e0efcb73e
--- /dev/null
+++ b/doc/manpage.d/ipsec_spigrp.5.html
@@ -0,0 +1,193 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_SPIGRP</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_SPIGRP</H1>
+Section: File Formats (5)<BR>Updated: 27 Jun 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec_spigrp - list IPSEC Security Association groupings
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>spigrp</B>
+
+<P>
+
+<B>cat</B>
+
+<B>/proc/net/ipsec_spigrp</B>
+
+<P>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>/proc/net/ipsec_spigrp</I>
+
+is a read-only file that lists groups of IPSEC Security Associations
+(SAs).
+<P>
+
+An entry in the IPSEC extended routing table can only point (via an
+SAID) to one SA.  If more than one transform must be applied to a given
+type of packet, this can be accomplished by setting up several SAs with
+the same destination address but potentially different SPIs and
+protocols, and grouping them with
+<I><A HREF="ipsec_spigrp.8.html">ipsec_spigrp</A>(8)</I>.
+
+<P>
+
+The SA groups are listed, one line per connection/group, as a sequence
+of SAs to be applied (or that should have been applied, in the case of
+an incoming packet) from inside to outside the packet.  An SA is
+identified by its SAID, which consists of protocol (&quot;ah&quot;, &quot;esp&quot;, &quot;comp&quot; or
+&quot;tun&quot;), SPI (with '.' for IPv4 or ':' for IPv6 prefixed hexadecimal number ) and destination address
+(IPv4 dotted quad or IPv6 coloned hex) prefixed by '@', in the format &lt;proto&gt;&lt;af&gt;&lt;spi&gt;@&lt;dest&gt;.
+<A NAME="lbAE">&nbsp;</A>
+<H2>EXAMPLES</H2>
+
+<DL COMPACT>
+<DT><B><A HREF="mailto:tun.3d0@192.168.2.110">tun.3d0@192.168.2.110</A></B>
+
+<DD>
+<B><A HREF="mailto:comp.3d0@192.168.2.110">comp.3d0@192.168.2.110</A></B>
+
+<B><A HREF="mailto:esp.187a101b@192.168.2.110">esp.187a101b@192.168.2.110</A></B>
+
+<B><A HREF="mailto:ah.187a101a@192.168.2.110">ah.187a101a@192.168.2.110</A> </B>
+
+</DL>
+<P>
+
+is a group of 3 SAs, destined for 
+<B>192.168.2.110</B>
+
+with an IPv4-in-IPv4 tunnel SA applied first with an SPI of
+<B>3d0</B>
+
+in hexadecimal, followed by a Deflate compression header to compress
+the packet with CPI of
+<B>3d0</B>
+
+in hexadecimal, followed by an Encapsulating Security Payload header to
+encrypt the packet with SPI
+<B>187a101b</B>
+
+in hexadecimal, followed by an Authentication Header to authenticate the
+packet with SPI
+<B>187a101a</B>
+
+in hexadecimal, applied from inside to outside the packet.  This could
+be an incoming or outgoing group, depending on the address of the local
+machine.
+<P>
+
+<DL COMPACT>
+<DT><B>tun:<A HREF="mailto:3d0@3049">3d0@3049</A>:1::2</B>
+
+<DD>
+<B>comp:<A HREF="mailto:3d0@3049">3d0@3049</A>:1::2</B>
+
+<B>esp:<A HREF="mailto:187a101b@3049">187a101b@3049</A>:1::2</B>
+
+<B>ah:<A HREF="mailto:187a101a@3049">187a101a@3049</A>:1::2 </B>
+
+</DL>
+<P>
+
+is a group of 3 SAs, destined for 
+<B>3049:1::2</B>
+
+with an IPv6-in-IPv6 tunnel SA applied first with an SPI of
+<B>3d0</B>
+
+in hexadecimal, followed by a Deflate compression header to compress
+the packet with CPI of
+<B>3d0</B>
+
+in hexadecimal, followed by an Encapsulating Security Payload header to
+encrypt the packet with SPI
+<B>187a101b</B>
+
+in hexadecimal, followed by an Authentication Header to authenticate the
+packet with SPI
+<B>187a101a</B>
+
+in hexadecimal, applied from inside to outside the packet.  This could
+be an incoming or outgoing group, depending on the address of the local
+machine.
+<P>
+
+<A NAME="lbAF">&nbsp;</A>
+<H2>FILES</H2>
+
+/proc/net/ipsec_spigrp, /usr/local/bin/ipsec
+<A NAME="lbAG">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_manual.8.html">ipsec_manual</A>(8), <A HREF="ipsec_tncfg.5.html">ipsec_tncfg</A>(5), <A HREF="ipsec_eroute.5.html">ipsec_eroute</A>(5),
+<A HREF="ipsec_spi.5.html">ipsec_spi</A>(5), <A HREF="ipsec_klipsdebug.5.html">ipsec_klipsdebug</A>(5), <A HREF="ipsec_spigrp.8.html">ipsec_spigrp</A>(8), <A HREF="ipsec_version.5.html">ipsec_version</A>(5),
+<A HREF="ipsec_pf_key.5.html">ipsec_pf_key</A>(5)
+<A NAME="lbAH">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Richard Guy Briggs.
+<A NAME="lbAI">&nbsp;</A>
+<H2>BUGS</H2>
+
+:-)
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">EXAMPLES</A><DD>
+<DT><A HREF="#lbAF">FILES</A><DD>
+<DT><A HREF="#lbAG">SEE ALSO</A><DD>
+<DT><A HREF="#lbAH">HISTORY</A><DD>
+<DT><A HREF="#lbAI">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_spigrp.8.html b/doc/manpage.d/ipsec_spigrp.8.html
new file mode 100644
index 000000000..2e96c0574
--- /dev/null
+++ b/doc/manpage.d/ipsec_spigrp.8.html
@@ -0,0 +1,280 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_SPIGRP</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_SPIGRP</H1>
+Section: Maintenance Commands (8)<BR>Updated: 21 Jun 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec spigrp - group/ungroup IPSEC Security Associations
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>spigrp</B>
+
+<P>
+
+<B>ipsec</B>
+
+<B>spigrp</B>
+
+[
+<B>--label</B>
+
+label ]
+af1 dst1 spi1 proto1 [ af2 dst2 spi2 proto2 [ af3 dst3 spi3 proto3 [ af4 dst4 spi4 proto4 ] ] ] 
+<P>
+
+<B>ipsec</B>
+
+<B>spigrp</B>
+
+[
+<B>--label</B>
+
+label ]
+<B>--said</B>
+
+SA1 [ SA2 [ SA3 [ SA4 ] ] ] 
+<P>
+
+<B>ipsec</B>
+
+<B>spigrp</B>
+
+<B>--help</B>
+
+<P>
+
+<B>ipsec</B>
+
+<B>spigrp</B>
+
+<B>--version</B>
+
+<P>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Spigrp</I>
+
+groups IPSEC Security Associations (SAs) together or ungroups
+previously grouped SAs.
+An entry in the IPSEC extended
+routing table can only point
+(via a destination address, a Security Parameters Index (SPI) and
+a protocol identifier) to one SA.
+If more than one transform must be applied to a given type of packet,
+this can be accomplished by setting up several SAs
+with the same destination address but potentially different SPIs and protocols,
+and grouping them with
+<I>spigrp</I>.
+
+<P>
+
+The SAs to be grouped,
+specified by destination address (DNS name lookup, IPv4 dotted quad or IPv6 coloned hex), SPI
+('0x'-prefixed hexadecimal number) and protocol (&quot;ah&quot;, &quot;esp&quot;, &quot;comp&quot; or &quot;tun&quot;),
+are listed from the inside transform to the
+outside;
+in other words, the transforms are applied in
+the order of the command line and removed in the reverse
+order.
+The resulting SA group is referred to by its first SA (by
+<I>af1</I>,
+
+<I>dst1</I>,
+
+<I>spi1</I>
+
+and
+<I>proto1</I>).
+
+<P>
+
+The --said option indicates that the SA IDs are to be specified as
+one argument each, in the format &lt;proto&gt;&lt;af&gt;&lt;spi&gt;@&lt;dest&gt;.  The SA IDs must
+all be specified as separate parameters without the --said option or
+all as monolithic parameters after the --said option.
+<P>
+
+The SAs must already exist and must not already
+be part of a group.
+<P>
+
+If
+<I>spigrp</I>
+
+is invoked with only one SA specification,
+it ungroups the previously-grouped set of SAs containing
+the SA specified.
+<P>
+
+The --label option identifies all responses from that command
+invocation with a user-supplied label, provided as an argument to the
+label option.  This can be helpful for debugging one invocation of the
+command out of a large number.
+<P>
+
+The command form with no additional arguments lists the contents of
+/proc/net/ipsec_spigrp.  The format of /proc/net/ipsec_spigrp is
+discussed in <A HREF="ipsec_spigrp.5.html">ipsec_spigrp</A>(5).
+<A NAME="lbAE">&nbsp;</A>
+<H2>EXAMPLES</H2>
+
+<DL COMPACT>
+<DT><B>ipsec spigrp inet gw2 0x113 tun inet gw2 0x115 esp inet gw2 0x116 ah</B>
+
+<DD>
+groups 3 SAs together, all destined for
+<B>gw2</B>,
+
+but with an IPv4-in-IPv4 tunnel SA applied first with SPI
+<B>0x113</B>,
+
+then an ESP header to encrypt the packet with SPI
+<B>0x115</B>,
+
+and finally an AH header to authenticate the packet with SPI
+<B>0x116</B>.
+
+</DL>
+<P>
+
+<DL COMPACT>
+<DT><B>ipsec spigrp --said tun.113@gw2 esp.115@gw2 ah.116@gw2 </B>
+
+<DD>
+groups 3 SAs together, all destined for
+<B>gw2</B>,
+
+but with an IPv4-in-IPv4 tunnel SA applied first with SPI
+<B>0x113</B>,
+
+then an ESP header to encrypt the packet with SPI
+<B>0x115</B>,
+
+and finally an AH header to authenticate the packet with SPI
+<B>0x116</B>.
+
+</DL>
+<P>
+
+<DL COMPACT>
+<DT><B>ipsec spigrp --said tun:<A HREF="mailto:233@3049">233@3049</A>:1::1 esp:<A HREF="mailto:235@3049">235@3049</A>:1::1 ah:<A HREF="mailto:236@3049">236@3049</A>:1::1 </B>
+
+<DD>
+groups 3 SAs together, all destined for
+<B>3049:1::1,</B>
+
+but with an IPv6-in-IPv6 tunnel SA applied first with SPI
+<B>0x233</B>,
+
+then an ESP header to encrypt the packet with SPI
+<B>0x235</B>,
+
+and finally an AH header to authenticate the packet with SPI
+<B>0x236</B>.
+
+</DL>
+<P>
+
+<DL COMPACT>
+<DT><B>ipsec spigrp inet6 3049:1::1 0x233 tun inet6 3049:1::1 0x235 esp inet6 3049:1::1 0x236 ah</B>
+
+<DD>
+groups 3 SAs together, all destined for
+<B>3049:1::1,</B>
+
+but with an IPv6-in-IPv6 tunnel SA applied first with SPI
+<B>0x233</B>,
+
+then an ESP header to encrypt the packet with SPI
+<B>0x235</B>,
+
+and finally an AH header to authenticate the packet with SPI
+<B>0x236</B>.
+
+</DL>
+<P>
+
+<A NAME="lbAF">&nbsp;</A>
+<H2>FILES</H2>
+
+/proc/net/ipsec_spigrp, /usr/local/bin/ipsec
+<A NAME="lbAG">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_manual.8.html">ipsec_manual</A>(8), <A HREF="ipsec_tncfg.8.html">ipsec_tncfg</A>(8), <A HREF="ipsec_eroute.8.html">ipsec_eroute</A>(8),
+<A HREF="ipsec_spi.8.html">ipsec_spi</A>(8), <A HREF="ipsec_klipsdebug.8.html">ipsec_klipsdebug</A>(8), <A HREF="ipsec_spigrp.5.html">ipsec_spigrp</A>(5)
+<A NAME="lbAH">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Richard Guy Briggs.
+<A NAME="lbAI">&nbsp;</A>
+<H2>BUGS</H2>
+
+Yes, it really is limited to a maximum of four SAs,
+although admittedly it's hard to see why you would need more.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">EXAMPLES</A><DD>
+<DT><A HREF="#lbAF">FILES</A><DD>
+<DT><A HREF="#lbAG">SEE ALSO</A><DD>
+<DT><A HREF="#lbAH">HISTORY</A><DD>
+<DT><A HREF="#lbAI">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_splitkeytoid.3.html b/doc/manpage.d/ipsec_splitkeytoid.3.html
new file mode 100644
index 000000000..109cfafa7
--- /dev/null
+++ b/doc/manpage.d/ipsec_splitkeytoid.3.html
@@ -0,0 +1,174 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_KEYBLOBTOID</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_KEYBLOBTOID</H1>
+Section: C Library Functions (3)<BR>Updated: 25 March 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec keyblobtoid, splitkeytoid - generate key IDs from RSA keys
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>size_t keyblobtoid(const unsigned char *blob,</B>
+
+<BR>
+&nbsp;
+<B>size_t bloblen, char *dst, size_t dstlen);</B>
+
+<BR>
+
+<B>size_t splitkeytoid(const unsigned char *e, size_t elen,</B>
+
+<BR>
+&nbsp;
+<B>const unsigned char *m, size_t mlen, char *dst,</B>
+
+<BR>
+&nbsp;
+<B>size_t dstlen);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Keyblobtoid</I>
+
+and
+<I>splitkeytoid</I>
+
+generate
+key IDs
+from RSA keys,
+for use in messages and reporting,
+writing the result to
+<I>dst</I>.
+
+A
+<I>key ID</I>
+
+is a short ASCII string identifying a key;
+currently it is just the first nine characters of the base64
+encoding of the RFC 2537/3110 ``byte blob'' representation of the key.
+(Beware that no finite key ID can be collision-proof:
+there is always some small chance of two random keys having the
+same ID.)
+<P>
+
+<I>Keyblobtoid</I>
+
+generates a key ID from a key which is already in the form of an
+RFC 2537/3110 binary key
+<I>blob</I>
+
+(encoded exponent length, exponent, modulus).
+<P>
+
+<I>Splitkeytoid</I>
+
+generates a key ID from a key given in the form of a separate
+(binary) exponent
+<I>e</I>
+
+and modulus
+<I>m</I>.
+
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of either
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+The
+<I>freeswan.h</I>
+
+header file defines a constant
+<B>KEYID_BUF</B>
+
+which is the size of a buffer large enough for worst-case results.
+<P>
+
+Both functions return
+<B>0</B>
+
+for a failure, and otherwise
+always return the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL;
+it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred.
+
+With keys generated by
+<I><A HREF="ipsec_rsasigkey.3.html">ipsec_rsasigkey</A></I>(3),
+
+the first two base64 digits are always the same,
+and the third carries only about one bit of information.
+It's worse with keys using longer fixed exponents,
+e.g. the 24-bit exponent that's common in X.509 certificates.
+However, being able to relate key IDs to the full
+base64 text form of keys by eye is sufficiently useful that this
+waste of space seems justifiable.
+The choice of nine digits is a compromise between bulk and
+probability of collision.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+RFC 3110,
+<I>RSA/SHA-1 SIGs and RSA KEYs in the Domain Name System (DNS)</I>,
+Eastlake, 2001
+(superseding the older but better-known RFC 2537).
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors are:
+key too short to supply enough bits to construct a complete key ID
+(almost certainly indicating a garbage key);
+exponent too long for its length to be representable.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_subnetinsubnet.3.html b/doc/manpage.d/ipsec_subnetinsubnet.3.html
new file mode 100644
index 000000000..414a0d513
--- /dev/null
+++ b/doc/manpage.d/ipsec_subnetinsubnet.3.html
@@ -0,0 +1,274 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ANYADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ANYADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 28 Nov 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec sameaddr - are two addresses the same?
+<BR>
+
+ipsec addrcmp - ordered comparison of addresses
+<BR>
+
+ipsec samesubnet - are two subnets the same?
+<BR>
+
+ipsec addrinsubnet - is an address within a subnet?
+<BR>
+
+ipsec subnetinsubnet - is a subnet within another subnet?
+<BR>
+
+ipsec subnetishost - is a subnet a single host?
+<BR>
+
+ipsec samesaid - are two SA IDs the same?
+<BR>
+
+ipsec sameaddrtype - are two addresses of the same address family?
+<BR>
+
+ipsec samesubnettype - are two subnets of the same address family?
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>int sameaddr(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int addrcmp(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int samesubnet(const ip_subnet *a, const ip_subnet *b);</B>
+
+<BR>
+
+<B>int addrinsubnet(const ip_address *a, const ip_subnet *s);</B>
+
+<BR>
+
+<B>int subnetinsubnet(const ip_subnet *a, const ip_subnet *b);</B>
+
+<BR>
+
+<B>int subnetishost(const ip_subnet *s);</B>
+
+<BR>
+
+<B>int samesaid(const ip_said *a, const ip_said *b);</B>
+
+<BR>
+
+<B>int sameaddrtype(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int samesubnettype(const ip_subnet *a, const ip_subnet *b);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions do various comparisons and tests on the
+<I>ip_address</I>
+
+type and
+<I>ip_subnet</I>
+
+types.
+<P>
+
+<I>Sameaddr</I>
+
+returns
+non-zero
+if addresses
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+Addresses of different families are never identical.
+<P>
+
+<I>Addrcmp</I>
+
+returns
+<B>-1</B>,
+
+<B>0</B>,
+
+or
+<B>1</B>
+
+respectively
+if address
+<I>a</I>
+
+is less than, equal to, or greater than
+<I>b</I>.
+
+If they are not of the same address family,
+they are never equal;
+the ordering reported in this case is arbitrary
+(and probably not useful) but consistent.
+<P>
+
+<I>Samesubnet</I>
+
+returns
+non-zero
+if subnets
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+Subnets of different address families are never identical.
+<P>
+
+<I>Addrinsubnet</I>
+
+returns
+non-zero
+if address
+<I>a</I>
+
+is within subnet
+<I>s</I>
+
+and
+<B>0</B>
+
+otherwise.
+An address is never within a
+subnet of a different address family.
+<P>
+
+<I>Subnetinsubnet</I>
+
+returns
+non-zero
+if subnet
+<I>a</I>
+
+is a subset of subnet
+<I>b</I>
+
+and
+<B>0</B>
+
+otherwise.
+A subnet is deemed to be a subset of itself.
+A subnet is never a subset of another
+subnet if their address families differ.
+<P>
+
+<I>Subnetishost</I>
+
+returns
+non-zero
+if subnet
+<I>s</I>
+
+is in fact only a single host,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Samesaid</I>
+
+returns
+non-zero
+if SA IDs
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Sameaddrtype</I>
+
+returns
+non-zero
+if addresses
+<I>a</I>
+
+and
+<I>b</I>
+
+are of the same address family,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Samesubnettype</I>
+
+returns
+non-zero
+if subnets
+<I>a</I>
+
+and
+<I>b</I>
+
+are of the same address family,
+and
+<B>0</B>
+
+otherwise.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_initaddr.3.html">ipsec_initaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_subnetishost.3.html b/doc/manpage.d/ipsec_subnetishost.3.html
new file mode 100644
index 000000000..414a0d513
--- /dev/null
+++ b/doc/manpage.d/ipsec_subnetishost.3.html
@@ -0,0 +1,274 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ANYADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ANYADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 28 Nov 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec sameaddr - are two addresses the same?
+<BR>
+
+ipsec addrcmp - ordered comparison of addresses
+<BR>
+
+ipsec samesubnet - are two subnets the same?
+<BR>
+
+ipsec addrinsubnet - is an address within a subnet?
+<BR>
+
+ipsec subnetinsubnet - is a subnet within another subnet?
+<BR>
+
+ipsec subnetishost - is a subnet a single host?
+<BR>
+
+ipsec samesaid - are two SA IDs the same?
+<BR>
+
+ipsec sameaddrtype - are two addresses of the same address family?
+<BR>
+
+ipsec samesubnettype - are two subnets of the same address family?
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>int sameaddr(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int addrcmp(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int samesubnet(const ip_subnet *a, const ip_subnet *b);</B>
+
+<BR>
+
+<B>int addrinsubnet(const ip_address *a, const ip_subnet *s);</B>
+
+<BR>
+
+<B>int subnetinsubnet(const ip_subnet *a, const ip_subnet *b);</B>
+
+<BR>
+
+<B>int subnetishost(const ip_subnet *s);</B>
+
+<BR>
+
+<B>int samesaid(const ip_said *a, const ip_said *b);</B>
+
+<BR>
+
+<B>int sameaddrtype(const ip_address *a, const ip_address *b);</B>
+
+<BR>
+
+<B>int samesubnettype(const ip_subnet *a, const ip_subnet *b);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions do various comparisons and tests on the
+<I>ip_address</I>
+
+type and
+<I>ip_subnet</I>
+
+types.
+<P>
+
+<I>Sameaddr</I>
+
+returns
+non-zero
+if addresses
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+Addresses of different families are never identical.
+<P>
+
+<I>Addrcmp</I>
+
+returns
+<B>-1</B>,
+
+<B>0</B>,
+
+or
+<B>1</B>
+
+respectively
+if address
+<I>a</I>
+
+is less than, equal to, or greater than
+<I>b</I>.
+
+If they are not of the same address family,
+they are never equal;
+the ordering reported in this case is arbitrary
+(and probably not useful) but consistent.
+<P>
+
+<I>Samesubnet</I>
+
+returns
+non-zero
+if subnets
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+Subnets of different address families are never identical.
+<P>
+
+<I>Addrinsubnet</I>
+
+returns
+non-zero
+if address
+<I>a</I>
+
+is within subnet
+<I>s</I>
+
+and
+<B>0</B>
+
+otherwise.
+An address is never within a
+subnet of a different address family.
+<P>
+
+<I>Subnetinsubnet</I>
+
+returns
+non-zero
+if subnet
+<I>a</I>
+
+is a subset of subnet
+<I>b</I>
+
+and
+<B>0</B>
+
+otherwise.
+A subnet is deemed to be a subset of itself.
+A subnet is never a subset of another
+subnet if their address families differ.
+<P>
+
+<I>Subnetishost</I>
+
+returns
+non-zero
+if subnet
+<I>s</I>
+
+is in fact only a single host,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Samesaid</I>
+
+returns
+non-zero
+if SA IDs
+<I>a</I>
+
+and
+<I>b</I>
+
+are identical,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Sameaddrtype</I>
+
+returns
+non-zero
+if addresses
+<I>a</I>
+
+and
+<I>b</I>
+
+are of the same address family,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+<I>Samesubnettype</I>
+
+returns
+non-zero
+if subnets
+<I>a</I>
+
+and
+<I>b</I>
+
+are of the same address family,
+and
+<B>0</B>
+
+otherwise.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_initaddr.3.html">ipsec_initaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_subnetof.3.html b/doc/manpage.d/ipsec_subnetof.3.html
new file mode 100644
index 000000000..a185d716b
--- /dev/null
+++ b/doc/manpage.d/ipsec_subnetof.3.html
@@ -0,0 +1,107 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_SUBNETOF</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_SUBNETOF</H1>
+Section: C Library Functions (3)<BR>Updated: 11 June 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec subnetof - given Internet address and subnet mask, return subnet number
+<BR>
+
+ipsec hostof - given Internet address and subnet mask, return host part
+<BR>
+
+ipsec broadcastof - given Internet address and subnet mask, return broadcast address
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>struct in_addr subnetof(struct in_addr addr,</B>
+
+<BR>
+&nbsp;
+<B>struct in_addr mask);</B>
+
+<BR>
+
+<B>struct in_addr hostof(struct in_addr addr,</B>
+
+<BR>
+&nbsp;
+<B>struct in_addr mask);</B>
+
+<BR>
+
+<B>struct in_addr broadcastof(struct in_addr addr,</B>
+
+<BR>
+&nbsp;
+<B>struct in_addr mask);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions are obsolete; see
+<I><A HREF="ipsec_networkof.3.html">ipsec_networkof</A></I>(3)
+
+for their replacements.
+<P>
+
+<I>Subnetof</I>
+
+takes an Internet
+<I>address</I>
+
+and a subnet
+<I>mask</I>
+
+and returns the network part of the address
+(all in network byte order).
+<I>Hostof</I>
+
+similarly returns the host part, and
+<I>broadcastof</I>
+
+returns the broadcast address (all-1s convention) for the network.
+<P>
+
+These functions are provided to hide the Internet bit-munging inside
+an API, in hopes of easing the eventual transition to IPv6.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_atosubnet.3.html">ipsec_atosubnet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAG">&nbsp;</A>
+<H2>BUGS</H2>
+
+Calling functions for this is more costly than doing it yourself.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+<DT><A HREF="#lbAG">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_subnettoa.3.html b/doc/manpage.d/ipsec_subnettoa.3.html
new file mode 100644
index 000000000..718fa935a
--- /dev/null
+++ b/doc/manpage.d/ipsec_subnettoa.3.html
@@ -0,0 +1,448 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ATOADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ATOADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 11 June 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec atoaddr, addrtoa - convert Internet addresses to and from ASCII
+<BR>
+
+ipsec atosubnet, subnettoa - convert subnet/mask ASCII form to and from addresses
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *atoaddr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>struct in_addr *addr);</B>
+
+<BR>
+
+<B>size_t addrtoa(struct in_addr addr, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<P>
+<B>const char *atosubnet(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>struct in_addr *addr, struct in_addr *mask);</B>
+
+<BR>
+
+<B>size_t subnettoa(struct in_addr addr, struct in_addr mask,</B>
+
+<BR>
+&nbsp;
+<B>int format, char *dst, size_t dstlen);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions are obsolete; see
+<I><A HREF="ipsec_ttoaddr.3.html">ipsec_ttoaddr</A></I>(3)
+
+for their replacements.
+<P>
+
+<I>Atoaddr</I>
+
+converts an ASCII name or dotted-decimal address into a binary address
+(in network byte order).
+<I>Addrtoa</I>
+
+does the reverse conversion, back to an ASCII dotted-decimal address.
+<I>Atosubnet</I>
+
+and
+<I>subnettoa</I>
+
+do likewise for the ``address/mask'' ASCII form used to write a
+specification of a subnet.
+<P>
+
+An address is specified in ASCII as a
+dotted-decimal address (e.g.
+<B>1.2.3.4</B>),
+
+an eight-digit network-order hexadecimal number with the usual C prefix (e.g.
+<B>0x01020304</B>,
+
+which is synonymous with
+<B>1.2.3.4</B>),
+
+an eight-digit host-order hexadecimal number with a
+<B>0h</B>
+
+prefix (e.g.
+<B>0h01020304</B>,
+
+which is synonymous with
+<B>1.2.3.4</B>
+
+on a big-endian host and
+<B>4.3.2.1</B>
+
+on a little-endian host),
+a DNS name to be looked up via
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3),
+
+or an old-style network name to be looked up via
+<I><A HREF="getnetbyname.3.html">getnetbyname</A></I>(3).
+
+<P>
+
+A dotted-decimal address may be incomplete, in which case
+ASCII-to-binary conversion implicitly appends
+as many instances of
+<B>.0</B>
+
+as necessary to bring it up to four components.
+The components of a dotted-decimal address are always taken as
+decimal, and leading zeros are ignored.
+For example,
+<B>10</B>
+
+is synonymous with
+<B>10.0.0.0</B>,
+
+and
+<B>128.009.000.032</B>
+
+is synonymous with
+<B>128.9.0.32</B>
+
+(the latter example is verbatim from RFC 1166).
+The result of
+<I>addrtoa</I>
+
+is always complete and does not contain leading zeros.
+<P>
+
+The letters in
+a hexadecimal address may be uppercase or lowercase or any mixture thereof.
+Use of hexadecimal addresses is
+<B>strongly</B>
+
+<B>discouraged</B>;
+
+they are included only to save hassles when dealing with
+the handful of perverted programs which already print 
+network addresses in hexadecimal.
+<P>
+
+DNS names may be complete (optionally terminated with a ``.'')
+or incomplete, and are looked up as specified by local system configuration
+(see
+<I><A HREF="resolver.5.html">resolver</A></I>(5)).
+
+The
+<I>h_addr</I>
+
+value returned by
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3)
+
+is used,
+so with current DNS implementations,
+the result when the name corresponds to more than one address is
+difficult to predict.
+Name lookup resorts to
+<I><A HREF="getnetbyname.3.html">getnetbyname</A></I>(3)
+
+only if
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3)
+
+fails.
+<P>
+
+A subnet specification is of the form <I>network</I><B>/</B><I>mask</I>.
+The
+<I>network</I>
+
+and
+<I>mask</I>
+
+can be any form acceptable to
+<I>atoaddr</I>.
+
+In addition, the
+<I>mask</I>
+
+can be a decimal integer (leading zeros ignored) giving a bit count,
+in which case
+it stands for a mask with that number of high bits on and all others off
+(e.g.,
+<B>24</B>
+
+means
+<B>255.255.255.0</B>).
+
+In any case, the mask must be contiguous
+(a sequence of high bits on and all remaining low bits off).
+As a special case, the subnet specification
+<B>%default</B>
+
+is a synonym for
+<B>0.0.0.0/0</B>.
+
+<P>
+
+<I>Atosubnet</I>
+
+ANDs the mask with the address before returning,
+so that any non-network bits in the address are turned off
+(e.g.,
+<B>10.1.2.3/24</B>
+
+is synonymous with
+<B>10.1.2.0/24</B>).
+
+<I>Subnettoa</I>
+
+generates the decimal-integer-bit-count
+form of the mask,
+with no leading zeros,
+unless the mask is non-contiguous.
+<P>
+
+The
+<I>srclen</I>
+
+parameter of
+<I>atoaddr</I>
+
+and
+<I>atosubnet</I>
+
+specifies the length of the ASCII string pointed to by
+<I>src</I>;
+
+it is an error for there to be anything else
+(e.g., a terminating NUL) within that length.
+As a convenience for cases where an entire NUL-terminated string is
+to be converted,
+a
+<I>srclen</I>
+
+value of
+<B>0</B>
+
+is taken to mean
+<B>strlen(src)</B>.
+
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of
+<I>addrtoa</I>
+
+and
+<I>subnettoa</I>
+
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+The
+<I>freeswan.h</I>
+
+header file defines constants,
+<B>ADDRTOA_BUF</B>
+
+and
+<B>SUBNETTOA_BUF</B>,
+
+which are the sizes of buffers just large enough for worst-case results.
+<P>
+
+The
+<I>format</I>
+
+parameter of
+<I>addrtoa</I>
+
+and
+<I>subnettoa</I>
+
+specifies what format is to be used for the conversion.
+The value
+<B>0</B>
+
+(not the ASCII character
+<B>'0'</B>,
+
+but a zero value)
+specifies a reasonable default,
+and is in fact the only format currently available.
+This parameter is a hedge against future needs.
+<P>
+
+The ASCII-to-binary functions return NULL for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+The binary-to-ASCII functions return
+<B>0</B>
+
+for a failure, and otherwise
+always return the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL;
+it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>atoaddr</I>
+
+are:
+empty input;
+attempt to allocate temporary storage for a very long name failed;
+name lookup failed;
+syntax error in dotted-decimal form;
+dotted-decimal component too large to fit in 8 bits.
+<P>
+
+Fatal errors in
+<I>atosubnet</I>
+
+are:
+no
+<B>/</B>
+
+in
+<I>src</I>;
+
+<I>atoaddr</I>
+
+error in conversion of
+<I>network</I>
+
+or
+<I>mask</I>;
+
+bit-count mask too big;
+mask non-contiguous.
+<P>
+
+Fatal errors in
+<I>addrtoa</I>
+
+and
+<I>subnettoa</I>
+
+are:
+unknown format.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+The interpretation of incomplete dotted-decimal addresses
+(e.g.
+<B>10/24</B>
+
+means
+<B>10.0.0.0/24</B>)
+
+differs from that of some older conversion
+functions, e.g. those of
+<I><A HREF="inet.3.html">inet</A></I>(3).
+
+The behavior of the older functions has never been
+particularly consistent or particularly useful.
+<P>
+
+Ignoring leading zeros in dotted-decimal components and bit counts
+is arguably the most useful behavior in this application,
+but it might occasionally cause confusion with the historical use of leading 
+zeros to denote octal numbers.
+<P>
+
+It is barely possible that somebody, somewhere,
+might have a legitimate use for non-contiguous subnet masks.
+<P>
+
+<I><A HREF="Getnetbyname.3.html">Getnetbyname</A></I>(3)
+
+is a historical dreg.
+<P>
+
+The restriction of ASCII-to-binary error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The ASCII-to-binary error-reporting convention lends itself
+to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = atoaddr( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_subnettot.3.html b/doc/manpage.d/ipsec_subnettot.3.html
new file mode 100644
index 000000000..199937a35
--- /dev/null
+++ b/doc/manpage.d/ipsec_subnettot.3.html
@@ -0,0 +1,569 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_TTOADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_TTOADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 28 Sept 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec ttoaddr, tnatoaddr, addrtot - convert Internet addresses to and from text
+<BR>
+
+ipsec ttosubnet, subnettot - convert subnet/mask text form to and from addresses
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *ttoaddr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int af, ip_address *addr);</B>
+
+<BR>
+
+<B>const char *tnatoaddr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int af, ip_address *addr);</B>
+
+<BR>
+
+<B>size_t addrtot(const ip_address *addr, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<P>
+<B>const char *ttosubnet(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int af, ip_subnet *dst);</B>
+
+<BR>
+
+<B>size_t subnettot(const ip_subnet *sub, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Ttoaddr</I>
+
+converts a text-string name or numeric address into a binary address
+(in network byte order).
+<I>Tnatoaddr</I>
+
+does the same conversion,
+but the only text forms it accepts are
+the ``official'' forms of
+numeric address (dotted-decimal for IPv4, colon-hex for IPv6).
+<I>Addrtot</I>
+
+does the reverse conversion, from binary address back to a text form.
+<I>Ttosubnet</I>
+
+and
+<I>subnettot</I>
+
+do likewise for the ``address/mask'' form used to write a
+specification of a subnet.
+<P>
+
+An IPv4 address is specified in text as a
+dotted-decimal address (e.g.
+<B>1.2.3.4</B>),
+
+an eight-digit network-order hexadecimal number with the usual C prefix (e.g.
+<B>0x01020304</B>,
+
+which is synonymous with
+<B>1.2.3.4</B>),
+
+an eight-digit host-order hexadecimal number with a
+<B>0h</B>
+
+prefix (e.g.
+<B>0h01020304</B>,
+
+which is synonymous with
+<B>1.2.3.4</B>
+
+on a big-endian host and
+<B>4.3.2.1</B>
+
+on a little-endian host),
+a DNS name to be looked up via
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3),
+
+or an old-style network name to be looked up via
+<I><A HREF="getnetbyname.3.html">getnetbyname</A></I>(3).
+
+<P>
+
+A dotted-decimal address may be incomplete, in which case
+text-to-binary conversion implicitly appends
+as many instances of
+<B>.0</B>
+
+as necessary to bring it up to four components.
+The components of a dotted-decimal address are always taken as
+decimal, and leading zeros are ignored.
+For example,
+<B>10</B>
+
+is synonymous with
+<B>10.0.0.0</B>,
+
+and
+<B>128.009.000.032</B>
+
+is synonymous with
+<B>128.9.0.32</B>
+
+(the latter example is verbatim from RFC 1166).
+The result of applying
+<I>addrtot</I>
+
+to an IPv4 address is always complete and does not contain leading zeros.
+<P>
+
+Use of hexadecimal addresses is
+<B>strongly</B>
+
+<B>discouraged</B>;
+
+they are included only to save hassles when dealing with
+the handful of perverted programs which already print 
+network addresses in hexadecimal.
+<P>
+
+An IPv6 address is specified in text with
+colon-hex notation (e.g.
+<B>0:56:78ab:22:33:44:55:66</B>),
+
+colon-hex with
+<B>::</B>
+
+abbreviating at most one subsequence of multiple zeros (e.g.
+<B>99:ab::54:068</B>,
+
+which is synonymous with
+<B>99:ab:0:0:0:0:54:68</B>),
+
+or a DNS name to be looked up via
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3).
+
+The result of applying
+<I>addrtot</I>
+
+to an IPv6 address will use
+<B>::</B>
+
+abbreviation if possible,
+and will not contain leading zeros.
+<P>
+
+The letters in hexadecimal
+may be uppercase or lowercase or any mixture thereof.
+<P>
+
+DNS names may be complete (optionally terminated with a ``.'')
+or incomplete, and are looked up as specified by local system configuration
+(see
+<I><A HREF="resolver.5.html">resolver</A></I>(5)).
+
+The
+<I>h_addr</I>
+
+value returned by
+<I><A HREF="gethostbyname2.3.html">gethostbyname2</A></I>(3)
+
+is used,
+so with current DNS implementations,
+the result when the name corresponds to more than one address is
+difficult to predict.
+IPv4 name lookup resorts to
+<I><A HREF="getnetbyname.3.html">getnetbyname</A></I>(3)
+
+only if
+<I><A HREF="gethostbyname2.3.html">gethostbyname2</A></I>(3)
+
+fails.
+<P>
+
+A subnet specification is of the form <I>network</I><B>/</B><I>mask</I>.
+The
+<I>network</I>
+
+and
+<I>mask</I>
+
+can be any form acceptable to
+<I>ttoaddr</I>.
+
+In addition, and preferably, the
+<I>mask</I>
+
+can be a decimal integer (leading zeros ignored) giving a bit count,
+in which case
+it stands for a mask with that number of high bits on and all others off
+(e.g.,
+<B>24</B>
+
+in IPv4 means
+<B>255.255.255.0</B>).
+
+In any case, the mask must be contiguous
+(a sequence of high bits on and all remaining low bits off).
+As a special case, the subnet specification
+<B>%default</B>
+
+is a synonym for
+<B>0.0.0.0/0</B>
+
+or
+<B>::/0</B>
+
+in IPv4 or IPv6 respectively.
+<P>
+
+<I>Ttosubnet</I>
+
+ANDs the mask with the address before returning,
+so that any non-network bits in the address are turned off
+(e.g.,
+<B>10.1.2.3/24</B>
+
+is synonymous with
+<B>10.1.2.0/24</B>).
+
+<I>Subnettot</I>
+
+always generates the decimal-integer-bit-count
+form of the mask,
+with no leading zeros.
+<P>
+
+The
+<I>srclen</I>
+
+parameter of
+<I>ttoaddr</I>
+
+and
+<I>ttosubnet</I>
+
+specifies the length of the text string pointed to by
+<I>src</I>;
+
+it is an error for there to be anything else
+(e.g., a terminating NUL) within that length.
+As a convenience for cases where an entire NUL-terminated string is
+to be converted,
+a
+<I>srclen</I>
+
+value of
+<B>0</B>
+
+is taken to mean
+<B>strlen(src)</B>.
+
+<P>
+
+The
+<I>af</I>
+
+parameter of
+<I>ttoaddr</I>
+
+and
+<I>ttosubnet</I>
+
+specifies the address family of interest.
+It should be either
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>.
+
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of
+<I>addrtot</I>
+
+and
+<I>subnettot</I>
+
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+The
+<I>freeswan.h</I>
+
+header file defines constants,
+<B>ADDRTOT_BUF</B>
+
+and
+<B>SUBNETTOT_BUF</B>,
+
+which are the sizes of buffers just large enough for worst-case results.
+<P>
+
+The
+<I>format</I>
+
+parameter of
+<I>addrtot</I>
+
+and
+<I>subnettot</I>
+
+specifies what format is to be used for the conversion.
+The value
+<B>0</B>
+
+(not the character
+<B>'0'</B>,
+
+but a zero value)
+specifies a reasonable default,
+and is in fact the only format currently available in
+<I>subnettot</I>.
+
+<I>Addrtot</I>
+
+also accepts format values
+<B>'r'</B>
+
+(signifying a text form suitable for DNS reverse lookups,
+e.g.
+<B>4.3.2.1.IN-ADDR.ARPA.</B>
+
+for IPv4 and
+RFC 2874 format for IPv6),
+and
+<B>'R'</B>
+
+(signifying an alternate reverse-lookup form,
+an error for IPv4 and RFC 1886 format for IPv6).
+Reverse-lookup names always end with a ``.''.
+<P>
+
+The text-to-binary functions return NULL for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+The binary-to-text functions return
+<B>0</B>
+
+for a failure, and otherwise
+always return the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL;
+it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>ttoaddr</I>
+
+are:
+empty input;
+unknown address family;
+attempt to allocate temporary storage for a very long name failed;
+name lookup failed;
+syntax error in dotted-decimal or colon-hex form;
+dotted-decimal or colon-hex component too large.
+<P>
+
+Fatal errors in
+<I>ttosubnet</I>
+
+are:
+no
+<B>/</B>
+
+in
+<I>src</I>;
+
+<I>ttoaddr</I>
+
+error in conversion of
+<I>network</I>
+
+or
+<I>mask</I>;
+
+bit-count mask too big;
+mask non-contiguous.
+<P>
+
+Fatal errors in
+<I>addrtot</I>
+
+and
+<I>subnettot</I>
+
+are:
+unknown format.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+The interpretation of incomplete dotted-decimal addresses
+(e.g.
+<B>10/24</B>
+
+means
+<B>10.0.0.0/24</B>)
+
+differs from that of some older conversion
+functions, e.g. those of
+<I><A HREF="inet.3.html">inet</A></I>(3).
+
+The behavior of the older functions has never been
+particularly consistent or particularly useful.
+<P>
+
+Ignoring leading zeros in dotted-decimal components and bit counts
+is arguably the most useful behavior in this application,
+but it might occasionally cause confusion with the historical use of leading 
+zeros to denote octal numbers.
+<P>
+
+<I>Ttoaddr</I>
+
+does not support the mixed colon-hex-dotted-decimal
+convention used to embed an IPv4 address in an IPv6 address.
+<P>
+
+<I>Addrtot</I>
+
+always uses the
+<B>::</B>
+
+abbreviation (which can appear only once in an address) for the
+<I>first</I>
+
+sequence of multiple zeros in an IPv6 address.
+One can construct addresses (unlikely ones) in which this is suboptimal.
+<P>
+
+<I>Addrtot</I>
+
+<B>'r'</B>
+
+conversion of an IPv6 address uses lowercase hexadecimal,
+not the uppercase used in RFC 2874's examples.
+It takes careful reading of RFCs 2874, 2673, and 2234 to realize
+that lowercase is technically legitimate here,
+and there may be software which botches this
+and hence would have trouble with lowercase hex.
+<P>
+
+Possibly
+<I>subnettot</I>
+
+ought to recognize the
+<B>%default</B>
+
+case and generate that string as its output.
+Currently it doesn't.
+<P>
+
+It is barely possible that somebody, somewhere,
+might have a legitimate use for non-contiguous subnet masks.
+<P>
+
+<I><A HREF="Getnetbyname.3.html">Getnetbyname</A></I>(3)
+
+is a historical dreg.
+<P>
+
+<I>Tnatoaddr</I>
+
+probably should enforce completeness of dotted-decimal addresses.
+<P>
+
+The restriction of text-to-binary error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The text-to-binary error-reporting convention lends itself
+to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = ttoaddr( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_subnettypeof.3.html b/doc/manpage.d/ipsec_subnettypeof.3.html
new file mode 100644
index 000000000..ea0f83f82
--- /dev/null
+++ b/doc/manpage.d/ipsec_subnettypeof.3.html
@@ -0,0 +1,238 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_INITSUBNET</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_INITSUBNET</H1>
+Section: C Library Functions (3)<BR>Updated: 12 March 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec initsubnet - initialize an ip_subnet
+<BR>
+
+ipsec addrtosubnet - initialize a singleton ip_subnet
+<BR>
+
+ipsec subnettypeof - get address type of an ip_subnet
+<BR>
+
+ipsec masktocount - convert subnet mask to bit count
+<BR>
+
+ipsec networkof - get base address of an ip_subnet
+<BR>
+
+ipsec maskof - get subnet mask of an ip_subnet
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *initsubnet(const ip_address *addr,</B>
+
+<BR>
+&nbsp;
+<B>int maskbits, int clash, ip_subnet *dst);</B>
+
+<BR>
+
+<B>const char *addrtosubnet(const ip_address *addr,</B>
+
+<BR>
+&nbsp;
+<B>ip_subnet *dst);</B>
+
+<P>
+<B>int subnettypeof(const ip_subnet *src);</B>
+
+<BR>
+
+<B>int masktocount(const ip_address *src);</B>
+
+<BR>
+
+<B>void networkof(const ip_subnet *src, ip_address *dst);</B>
+
+<BR>
+
+<B>void maskof(const ip_subnet *src, ip_address *dst);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+library uses an internal type
+<I>ip_subnet</I>
+
+to contain a description of an IP subnet
+(base address plus mask).
+These functions provide basic tools for creating and examining this type.
+<P>
+
+<I>Initsubnet</I>
+
+initializes a variable
+<I>*dst</I>
+
+of type
+<I>ip_subnet</I>
+
+from a base address and
+a count of mask bits.
+The
+<I>clash</I>
+
+parameter specifies what to do if the base address includes
+<B>1</B>
+
+bits outside the prefix specified by the mask
+(that is, in the ``host number'' part of the address):
+<DL COMPACT><DT><DD>
+<DL COMPACT>
+<DT>'0'<DD>
+zero out host-number bits
+<DT>'x'<DD>
+non-zero host-number bits are an error
+</DL>
+</DL>
+
+<P>
+
+<I>Initsubnet</I>
+
+returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<P>
+
+<I>Addrtosubnet</I>
+
+initializes an
+<I>ip_subnet</I>
+
+variable
+<I>*dst</I>
+
+to a ``singleton subnet'' containing the single address
+<I>*addr</I>.
+
+It returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure.
+<P>
+
+<I>Subnettypeof</I>
+
+returns the address type of a subnet,
+normally
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>.
+
+(The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file arranges to include the necessary headers for these
+names to be known.)
+<P>
+
+<I>Masktocount</I>
+
+converts a subnet mask, expressed as an address, to a bit count
+suitable for use with
+<I>initsubnet</I>.
+
+It returns
+<B>-1</B>
+
+for error; see DIAGNOSTICS.
+<P>
+
+<I>Networkof</I>
+
+fills in
+<I>*dst</I>
+
+with the base address of subnet
+<I>src</I>.
+
+<P>
+
+<I>Maskof</I>
+
+fills in
+<I>*dst</I>
+
+with the subnet mask of subnet
+<I>src</I>,
+
+expressed as an address.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_ttosubnet.3.html">ipsec_ttosubnet</A>(3), <A HREF="ipsec_rangetosubnet.3.html">ipsec_rangetosubnet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>initsubnet</I>
+
+are:
+unknown address family;
+unknown
+<I>clash</I>
+
+value;
+impossible mask bit count;
+non-zero host-number bits and
+<I>clash</I>
+
+is
+<B>'x'</B>.
+
+Fatal errors in
+<I>addrtosubnet</I>
+
+are:
+unknown address family.
+Fatal errors in
+<I>masktocount</I>
+
+are:
+unknown address family;
+mask bits not contiguous.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_tnatoaddr.3.html b/doc/manpage.d/ipsec_tnatoaddr.3.html
new file mode 100644
index 000000000..199937a35
--- /dev/null
+++ b/doc/manpage.d/ipsec_tnatoaddr.3.html
@@ -0,0 +1,569 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_TTOADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_TTOADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 28 Sept 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec ttoaddr, tnatoaddr, addrtot - convert Internet addresses to and from text
+<BR>
+
+ipsec ttosubnet, subnettot - convert subnet/mask text form to and from addresses
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *ttoaddr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int af, ip_address *addr);</B>
+
+<BR>
+
+<B>const char *tnatoaddr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int af, ip_address *addr);</B>
+
+<BR>
+
+<B>size_t addrtot(const ip_address *addr, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<P>
+<B>const char *ttosubnet(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int af, ip_subnet *dst);</B>
+
+<BR>
+
+<B>size_t subnettot(const ip_subnet *sub, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Ttoaddr</I>
+
+converts a text-string name or numeric address into a binary address
+(in network byte order).
+<I>Tnatoaddr</I>
+
+does the same conversion,
+but the only text forms it accepts are
+the ``official'' forms of
+numeric address (dotted-decimal for IPv4, colon-hex for IPv6).
+<I>Addrtot</I>
+
+does the reverse conversion, from binary address back to a text form.
+<I>Ttosubnet</I>
+
+and
+<I>subnettot</I>
+
+do likewise for the ``address/mask'' form used to write a
+specification of a subnet.
+<P>
+
+An IPv4 address is specified in text as a
+dotted-decimal address (e.g.
+<B>1.2.3.4</B>),
+
+an eight-digit network-order hexadecimal number with the usual C prefix (e.g.
+<B>0x01020304</B>,
+
+which is synonymous with
+<B>1.2.3.4</B>),
+
+an eight-digit host-order hexadecimal number with a
+<B>0h</B>
+
+prefix (e.g.
+<B>0h01020304</B>,
+
+which is synonymous with
+<B>1.2.3.4</B>
+
+on a big-endian host and
+<B>4.3.2.1</B>
+
+on a little-endian host),
+a DNS name to be looked up via
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3),
+
+or an old-style network name to be looked up via
+<I><A HREF="getnetbyname.3.html">getnetbyname</A></I>(3).
+
+<P>
+
+A dotted-decimal address may be incomplete, in which case
+text-to-binary conversion implicitly appends
+as many instances of
+<B>.0</B>
+
+as necessary to bring it up to four components.
+The components of a dotted-decimal address are always taken as
+decimal, and leading zeros are ignored.
+For example,
+<B>10</B>
+
+is synonymous with
+<B>10.0.0.0</B>,
+
+and
+<B>128.009.000.032</B>
+
+is synonymous with
+<B>128.9.0.32</B>
+
+(the latter example is verbatim from RFC 1166).
+The result of applying
+<I>addrtot</I>
+
+to an IPv4 address is always complete and does not contain leading zeros.
+<P>
+
+Use of hexadecimal addresses is
+<B>strongly</B>
+
+<B>discouraged</B>;
+
+they are included only to save hassles when dealing with
+the handful of perverted programs which already print 
+network addresses in hexadecimal.
+<P>
+
+An IPv6 address is specified in text with
+colon-hex notation (e.g.
+<B>0:56:78ab:22:33:44:55:66</B>),
+
+colon-hex with
+<B>::</B>
+
+abbreviating at most one subsequence of multiple zeros (e.g.
+<B>99:ab::54:068</B>,
+
+which is synonymous with
+<B>99:ab:0:0:0:0:54:68</B>),
+
+or a DNS name to be looked up via
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3).
+
+The result of applying
+<I>addrtot</I>
+
+to an IPv6 address will use
+<B>::</B>
+
+abbreviation if possible,
+and will not contain leading zeros.
+<P>
+
+The letters in hexadecimal
+may be uppercase or lowercase or any mixture thereof.
+<P>
+
+DNS names may be complete (optionally terminated with a ``.'')
+or incomplete, and are looked up as specified by local system configuration
+(see
+<I><A HREF="resolver.5.html">resolver</A></I>(5)).
+
+The
+<I>h_addr</I>
+
+value returned by
+<I><A HREF="gethostbyname2.3.html">gethostbyname2</A></I>(3)
+
+is used,
+so with current DNS implementations,
+the result when the name corresponds to more than one address is
+difficult to predict.
+IPv4 name lookup resorts to
+<I><A HREF="getnetbyname.3.html">getnetbyname</A></I>(3)
+
+only if
+<I><A HREF="gethostbyname2.3.html">gethostbyname2</A></I>(3)
+
+fails.
+<P>
+
+A subnet specification is of the form <I>network</I><B>/</B><I>mask</I>.
+The
+<I>network</I>
+
+and
+<I>mask</I>
+
+can be any form acceptable to
+<I>ttoaddr</I>.
+
+In addition, and preferably, the
+<I>mask</I>
+
+can be a decimal integer (leading zeros ignored) giving a bit count,
+in which case
+it stands for a mask with that number of high bits on and all others off
+(e.g.,
+<B>24</B>
+
+in IPv4 means
+<B>255.255.255.0</B>).
+
+In any case, the mask must be contiguous
+(a sequence of high bits on and all remaining low bits off).
+As a special case, the subnet specification
+<B>%default</B>
+
+is a synonym for
+<B>0.0.0.0/0</B>
+
+or
+<B>::/0</B>
+
+in IPv4 or IPv6 respectively.
+<P>
+
+<I>Ttosubnet</I>
+
+ANDs the mask with the address before returning,
+so that any non-network bits in the address are turned off
+(e.g.,
+<B>10.1.2.3/24</B>
+
+is synonymous with
+<B>10.1.2.0/24</B>).
+
+<I>Subnettot</I>
+
+always generates the decimal-integer-bit-count
+form of the mask,
+with no leading zeros.
+<P>
+
+The
+<I>srclen</I>
+
+parameter of
+<I>ttoaddr</I>
+
+and
+<I>ttosubnet</I>
+
+specifies the length of the text string pointed to by
+<I>src</I>;
+
+it is an error for there to be anything else
+(e.g., a terminating NUL) within that length.
+As a convenience for cases where an entire NUL-terminated string is
+to be converted,
+a
+<I>srclen</I>
+
+value of
+<B>0</B>
+
+is taken to mean
+<B>strlen(src)</B>.
+
+<P>
+
+The
+<I>af</I>
+
+parameter of
+<I>ttoaddr</I>
+
+and
+<I>ttosubnet</I>
+
+specifies the address family of interest.
+It should be either
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>.
+
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of
+<I>addrtot</I>
+
+and
+<I>subnettot</I>
+
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+The
+<I>freeswan.h</I>
+
+header file defines constants,
+<B>ADDRTOT_BUF</B>
+
+and
+<B>SUBNETTOT_BUF</B>,
+
+which are the sizes of buffers just large enough for worst-case results.
+<P>
+
+The
+<I>format</I>
+
+parameter of
+<I>addrtot</I>
+
+and
+<I>subnettot</I>
+
+specifies what format is to be used for the conversion.
+The value
+<B>0</B>
+
+(not the character
+<B>'0'</B>,
+
+but a zero value)
+specifies a reasonable default,
+and is in fact the only format currently available in
+<I>subnettot</I>.
+
+<I>Addrtot</I>
+
+also accepts format values
+<B>'r'</B>
+
+(signifying a text form suitable for DNS reverse lookups,
+e.g.
+<B>4.3.2.1.IN-ADDR.ARPA.</B>
+
+for IPv4 and
+RFC 2874 format for IPv6),
+and
+<B>'R'</B>
+
+(signifying an alternate reverse-lookup form,
+an error for IPv4 and RFC 1886 format for IPv6).
+Reverse-lookup names always end with a ``.''.
+<P>
+
+The text-to-binary functions return NULL for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+The binary-to-text functions return
+<B>0</B>
+
+for a failure, and otherwise
+always return the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL;
+it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>ttoaddr</I>
+
+are:
+empty input;
+unknown address family;
+attempt to allocate temporary storage for a very long name failed;
+name lookup failed;
+syntax error in dotted-decimal or colon-hex form;
+dotted-decimal or colon-hex component too large.
+<P>
+
+Fatal errors in
+<I>ttosubnet</I>
+
+are:
+no
+<B>/</B>
+
+in
+<I>src</I>;
+
+<I>ttoaddr</I>
+
+error in conversion of
+<I>network</I>
+
+or
+<I>mask</I>;
+
+bit-count mask too big;
+mask non-contiguous.
+<P>
+
+Fatal errors in
+<I>addrtot</I>
+
+and
+<I>subnettot</I>
+
+are:
+unknown format.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+The interpretation of incomplete dotted-decimal addresses
+(e.g.
+<B>10/24</B>
+
+means
+<B>10.0.0.0/24</B>)
+
+differs from that of some older conversion
+functions, e.g. those of
+<I><A HREF="inet.3.html">inet</A></I>(3).
+
+The behavior of the older functions has never been
+particularly consistent or particularly useful.
+<P>
+
+Ignoring leading zeros in dotted-decimal components and bit counts
+is arguably the most useful behavior in this application,
+but it might occasionally cause confusion with the historical use of leading 
+zeros to denote octal numbers.
+<P>
+
+<I>Ttoaddr</I>
+
+does not support the mixed colon-hex-dotted-decimal
+convention used to embed an IPv4 address in an IPv6 address.
+<P>
+
+<I>Addrtot</I>
+
+always uses the
+<B>::</B>
+
+abbreviation (which can appear only once in an address) for the
+<I>first</I>
+
+sequence of multiple zeros in an IPv6 address.
+One can construct addresses (unlikely ones) in which this is suboptimal.
+<P>
+
+<I>Addrtot</I>
+
+<B>'r'</B>
+
+conversion of an IPv6 address uses lowercase hexadecimal,
+not the uppercase used in RFC 2874's examples.
+It takes careful reading of RFCs 2874, 2673, and 2234 to realize
+that lowercase is technically legitimate here,
+and there may be software which botches this
+and hence would have trouble with lowercase hex.
+<P>
+
+Possibly
+<I>subnettot</I>
+
+ought to recognize the
+<B>%default</B>
+
+case and generate that string as its output.
+Currently it doesn't.
+<P>
+
+It is barely possible that somebody, somewhere,
+might have a legitimate use for non-contiguous subnet masks.
+<P>
+
+<I><A HREF="Getnetbyname.3.html">Getnetbyname</A></I>(3)
+
+is a historical dreg.
+<P>
+
+<I>Tnatoaddr</I>
+
+probably should enforce completeness of dotted-decimal addresses.
+<P>
+
+The restriction of text-to-binary error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The text-to-binary error-reporting convention lends itself
+to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = ttoaddr( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_tncfg.5.html b/doc/manpage.d/ipsec_tncfg.5.html
new file mode 100644
index 000000000..e4082a28f
--- /dev/null
+++ b/doc/manpage.d/ipsec_tncfg.5.html
@@ -0,0 +1,175 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_TNCFG</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_TNCFG</H1>
+Section: File Formats (5)<BR>Updated: 27 Jun 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec_tncfg - lists IPSEC virtual interfaces attached to real interfaces
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>tncfg</B>
+
+<P>
+
+<B>cat</B>
+
+<B>/proc/net/ipsec_tncfg</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>/proc/net/ipsec_tncfg</I>
+
+is a read-only file which lists which IPSEC virtual interfaces are
+attached to which real interfaces, through which packets will be
+forwarded once processed by IPSEC.
+<P>
+
+Each line lists one ipsec I/F.
+A table entry consists of:
+<DL COMPACT>
+<DT>+<DD>
+an ipsec virtual I/F name
+<DT>+<DD>
+a visual and machine parsable separator '-&gt;', separating the virtual I/F
+and the physical I/F,
+<DT>+<DD>
+a physical I/F name, to which the ipsec virtual I/F is attached or NULL
+if it is not attached,
+<DT>+<DD>
+the keyword
+<B>mtu=</B>,
+
+<DT>+<DD>
+the MTU of the ipsec virtual I/F,
+<DT>+<DD>
+the automatically adjusted effective MTU for PMTU discovery, in brackets,
+<DT>+<DD>
+a visual and machine parsable separator '-&gt;', separating the virtual I/F
+MTU and the physical I/F MTU,
+<DT>+<DD>
+the MTU of the attached physical I/F.
+<B>.SH</B>EXAMPLES
+
+<DT><B>ipsec2 -&gt; eth3 mtu=16260(1443) -&gt; 1500</B>
+
+<DD>
+</DL>
+<P>
+
+shows that virtual device
+<B>ipsec2</B>
+
+with an MTU of
+<B>16260</B>
+
+is connected to physical device
+<B>eth3</B>
+
+with an MTU of
+<B>1500</B>
+
+and that the effective MTU as a result of PMTU discovery has been
+automatically set to
+<B>1443.</B>
+
+<DL COMPACT>
+<DT><B>ipsec0 -&gt; wvlan0 mtu=1400(16260) -&gt; 1500</B>
+
+<DD>
+</DL>
+<P>
+
+shows that virtual device
+<B>ipsec0</B>
+
+with an MTU of
+<B>1400</B>
+
+is connected to physical device
+<B>wvlan0</B>
+
+with an MTU of
+<B>1500</B>
+
+and no PMTU packets have gotten far enough to bump down the effective MTU
+from its default of 16260.
+<DL COMPACT>
+<DT><B>ipsec3 -&gt; NULL mtu=0(0) -&gt; 0</B>
+
+<DD>
+</DL>
+<P>
+
+shows that virtual device
+<B>ipsec3</B>
+
+is not connected to any physical device.
+<P>
+
+<A NAME="lbAE">&nbsp;</A>
+<H2>FILES</H2>
+
+/proc/net/ipsec_tncfg, /usr/local/bin/ipsec
+<A NAME="lbAF">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_manual.8.html">ipsec_manual</A>(8), <A HREF="ipsec_eroute.5.html">ipsec_eroute</A>(5), <A HREF="ipsec_spi.5.html">ipsec_spi</A>(5),
+<A HREF="ipsec_spigrp.5.html">ipsec_spigrp</A>(5), <A HREF="ipsec_klipsdebug.5.html">ipsec_klipsdebug</A>(5), <A HREF="ipsec_tncfg.8.html">ipsec_tncfg</A>(8), <A HREF="ipsec_version.5.html">ipsec_version</A>(5),
+<A HREF="ipsec_pf_key.5.html">ipsec_pf_key</A>(5)
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Richard Guy Briggs.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">FILES</A><DD>
+<DT><A HREF="#lbAF">SEE ALSO</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_tncfg.8.html b/doc/manpage.d/ipsec_tncfg.8.html
new file mode 100644
index 000000000..e5965267c
--- /dev/null
+++ b/doc/manpage.d/ipsec_tncfg.8.html
@@ -0,0 +1,195 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_TNCFG</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_TNCFG</H1>
+Section: Maintenance Commands (8)<BR>Updated: 21 Jun 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec tncfg - associate IPSEC virtual interface with physical interface
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>tncfg</B>
+
+<P>
+
+<B>ipsec</B>
+
+<B>tncfg</B>
+
+<B>--attach</B>
+
+<B>--virtual</B>
+
+virtual
+<B>--physical</B>
+
+physical
+<P>
+
+<B>ipsec</B>
+
+<B>tncfg</B>
+
+<B>--detach</B>
+
+<B>--virtual</B>
+
+virtual
+<P>
+
+<B>ipsec</B>
+
+<B>tncfg</B>
+
+<B>--clear</B>
+
+<P>
+
+<B>ipsec</B>
+
+<B>tncfg</B>
+
+<B>--version</B>
+
+<P>
+
+<B>ipsec</B>
+
+<B>tncfg</B>
+
+<B>--help</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Tncfg</I>
+
+attaches/detaches IPSEC virtual interfaces to/from
+physical interfaces,
+through which packets will be forwarded once processed by IPSEC.
+<P>
+
+The form with no additional arguments lists the contents of
+/proc/net/ipsec_tncfg.  The format of /proc/net/ipsec_tncfg is discussed
+in <A HREF="ipsec_tncfg.5.html">ipsec_tncfg</A>(5).
+The
+<B>--attach</B>
+
+form attaches the
+<I>virtual</I>
+
+interface to the
+<I>physical</I>
+
+one.
+The
+<B>--detach</B>
+
+form detaches the
+<I>virtual</I>
+
+interface from whichever physical interface it is attached to.
+The
+<B>--clear</B>
+
+form clears all the
+<I>virtual</I>
+
+interfaces from whichever physical interfaces they were attached to.
+<P>
+
+Virtual interfaces typically have names like
+<B>ipsec0</B>,
+
+while physical interfaces typically have names like
+<B>eth0</B>
+
+or
+<B>ppp0</B>.
+
+<A NAME="lbAE">&nbsp;</A>
+<H2>EXAMPLES</H2>
+
+<DL COMPACT>
+<DT><B>ipsec tncfg --attach --virtual ipsec0 --physical eth0</B>
+
+<DD>
+attaches the
+<B>ipsec0</B>
+
+virtual device to the
+<B>eth0</B>
+
+physical device.
+</DL>
+<P>
+
+<A NAME="lbAF">&nbsp;</A>
+<H2>FILES</H2>
+
+/proc/net/ipsec_tncfg, /usr/local/bin/ipsec
+<A NAME="lbAG">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_manual.8.html">ipsec_manual</A>(8), <A HREF="ipsec_eroute.8.html">ipsec_eroute</A>(8), <A HREF="ipsec_spi.8.html">ipsec_spi</A>(8),
+<A HREF="ipsec_spigrp.8.html">ipsec_spigrp</A>(8), <A HREF="ipsec_klipsdebug.8.html">ipsec_klipsdebug</A>(8), <A HREF="ipsec_tncfg.5.html">ipsec_tncfg</A>(5)
+<A NAME="lbAH">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Richard Guy Briggs.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">EXAMPLES</A><DD>
+<DT><A HREF="#lbAF">FILES</A><DD>
+<DT><A HREF="#lbAG">SEE ALSO</A><DD>
+<DT><A HREF="#lbAH">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_trap_count.5.html b/doc/manpage.d/ipsec_trap_count.5.html
new file mode 100644
index 000000000..8da655f77
--- /dev/null
+++ b/doc/manpage.d/ipsec_trap_count.5.html
@@ -0,0 +1,74 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_TRAP_COUNT</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_TRAP_COUNT</H1>
+Section: File Formats (5)<BR>Updated: 19 Jun 2003<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+trap_count - KLIPS statistic on number of ACQUIREs
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>cat</B>
+
+<B>/proc/net/ipsec/stats/trap_count</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>/proc/net/ipsec/stats/trap_count</I>
+
+is a read-only file. It contains a hexadecimal number which records the
+number of attempts to send PF_ACQUIRE messages. Only those recorded by
+trap_sendcount were actually successfully passed to userland. Note that the
+userland may still have lost them on its own.
+<P>
+
+<A NAME="lbAE">&nbsp;</A>
+<H2>FILES</H2>
+
+/proc/net/ipsec/stats/trap_sendcount
+<A NAME="lbAF">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_pf_key.5.html">ipsec_pf_key</A>(5), <A HREF="trap_sendcount.5.html">trap_sendcount</A>(5), <A HREF="pluto.8.html">pluto</A>(8)
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Michael C. Richardson &lt;<A HREF="mailto:mcr@freeswan.org">mcr@freeswan.org</A>&gt;
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">FILES</A><DD>
+<DT><A HREF="#lbAF">SEE ALSO</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_trap_sendcount.5.html b/doc/manpage.d/ipsec_trap_sendcount.5.html
new file mode 100644
index 000000000..94f56b3a7
--- /dev/null
+++ b/doc/manpage.d/ipsec_trap_sendcount.5.html
@@ -0,0 +1,72 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_TRAP_SENDCOUNT</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_TRAP_SENDCOUNT</H1>
+Section: File Formats (5)<BR>Updated: 19 Jun 2003<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+trap_sendcount - KLIPS statistic on number of successful ACQUIREs
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>cat</B>
+
+<B>/proc/net/ipsec/stats/trap_sendcount</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>/proc/net/ipsec/stats/trap_sendcount</I>
+
+is a read-only file. It contains a hexadecimal number which records the
+number of successful PF_ACQUIRE messages that were sent.
+<P>
+
+<A NAME="lbAE">&nbsp;</A>
+<H2>FILES</H2>
+
+/proc/net/ipsec/stats/trap_sendcount
+<A NAME="lbAF">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_pf_key.5.html">ipsec_pf_key</A>(5), <A HREF="trap_count.5.html">trap_count</A>(5), <A HREF="pluto.8.html">pluto</A>(8)
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Michael C. Richardson &lt;<A HREF="mailto:mcr@freeswan.org">mcr@freeswan.org</A>&gt;
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">FILES</A><DD>
+<DT><A HREF="#lbAF">SEE ALSO</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_ttoaddr.3.html b/doc/manpage.d/ipsec_ttoaddr.3.html
new file mode 100644
index 000000000..199937a35
--- /dev/null
+++ b/doc/manpage.d/ipsec_ttoaddr.3.html
@@ -0,0 +1,569 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_TTOADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_TTOADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 28 Sept 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec ttoaddr, tnatoaddr, addrtot - convert Internet addresses to and from text
+<BR>
+
+ipsec ttosubnet, subnettot - convert subnet/mask text form to and from addresses
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *ttoaddr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int af, ip_address *addr);</B>
+
+<BR>
+
+<B>const char *tnatoaddr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int af, ip_address *addr);</B>
+
+<BR>
+
+<B>size_t addrtot(const ip_address *addr, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<P>
+<B>const char *ttosubnet(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int af, ip_subnet *dst);</B>
+
+<BR>
+
+<B>size_t subnettot(const ip_subnet *sub, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Ttoaddr</I>
+
+converts a text-string name or numeric address into a binary address
+(in network byte order).
+<I>Tnatoaddr</I>
+
+does the same conversion,
+but the only text forms it accepts are
+the ``official'' forms of
+numeric address (dotted-decimal for IPv4, colon-hex for IPv6).
+<I>Addrtot</I>
+
+does the reverse conversion, from binary address back to a text form.
+<I>Ttosubnet</I>
+
+and
+<I>subnettot</I>
+
+do likewise for the ``address/mask'' form used to write a
+specification of a subnet.
+<P>
+
+An IPv4 address is specified in text as a
+dotted-decimal address (e.g.
+<B>1.2.3.4</B>),
+
+an eight-digit network-order hexadecimal number with the usual C prefix (e.g.
+<B>0x01020304</B>,
+
+which is synonymous with
+<B>1.2.3.4</B>),
+
+an eight-digit host-order hexadecimal number with a
+<B>0h</B>
+
+prefix (e.g.
+<B>0h01020304</B>,
+
+which is synonymous with
+<B>1.2.3.4</B>
+
+on a big-endian host and
+<B>4.3.2.1</B>
+
+on a little-endian host),
+a DNS name to be looked up via
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3),
+
+or an old-style network name to be looked up via
+<I><A HREF="getnetbyname.3.html">getnetbyname</A></I>(3).
+
+<P>
+
+A dotted-decimal address may be incomplete, in which case
+text-to-binary conversion implicitly appends
+as many instances of
+<B>.0</B>
+
+as necessary to bring it up to four components.
+The components of a dotted-decimal address are always taken as
+decimal, and leading zeros are ignored.
+For example,
+<B>10</B>
+
+is synonymous with
+<B>10.0.0.0</B>,
+
+and
+<B>128.009.000.032</B>
+
+is synonymous with
+<B>128.9.0.32</B>
+
+(the latter example is verbatim from RFC 1166).
+The result of applying
+<I>addrtot</I>
+
+to an IPv4 address is always complete and does not contain leading zeros.
+<P>
+
+Use of hexadecimal addresses is
+<B>strongly</B>
+
+<B>discouraged</B>;
+
+they are included only to save hassles when dealing with
+the handful of perverted programs which already print 
+network addresses in hexadecimal.
+<P>
+
+An IPv6 address is specified in text with
+colon-hex notation (e.g.
+<B>0:56:78ab:22:33:44:55:66</B>),
+
+colon-hex with
+<B>::</B>
+
+abbreviating at most one subsequence of multiple zeros (e.g.
+<B>99:ab::54:068</B>,
+
+which is synonymous with
+<B>99:ab:0:0:0:0:54:68</B>),
+
+or a DNS name to be looked up via
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3).
+
+The result of applying
+<I>addrtot</I>
+
+to an IPv6 address will use
+<B>::</B>
+
+abbreviation if possible,
+and will not contain leading zeros.
+<P>
+
+The letters in hexadecimal
+may be uppercase or lowercase or any mixture thereof.
+<P>
+
+DNS names may be complete (optionally terminated with a ``.'')
+or incomplete, and are looked up as specified by local system configuration
+(see
+<I><A HREF="resolver.5.html">resolver</A></I>(5)).
+
+The
+<I>h_addr</I>
+
+value returned by
+<I><A HREF="gethostbyname2.3.html">gethostbyname2</A></I>(3)
+
+is used,
+so with current DNS implementations,
+the result when the name corresponds to more than one address is
+difficult to predict.
+IPv4 name lookup resorts to
+<I><A HREF="getnetbyname.3.html">getnetbyname</A></I>(3)
+
+only if
+<I><A HREF="gethostbyname2.3.html">gethostbyname2</A></I>(3)
+
+fails.
+<P>
+
+A subnet specification is of the form <I>network</I><B>/</B><I>mask</I>.
+The
+<I>network</I>
+
+and
+<I>mask</I>
+
+can be any form acceptable to
+<I>ttoaddr</I>.
+
+In addition, and preferably, the
+<I>mask</I>
+
+can be a decimal integer (leading zeros ignored) giving a bit count,
+in which case
+it stands for a mask with that number of high bits on and all others off
+(e.g.,
+<B>24</B>
+
+in IPv4 means
+<B>255.255.255.0</B>).
+
+In any case, the mask must be contiguous
+(a sequence of high bits on and all remaining low bits off).
+As a special case, the subnet specification
+<B>%default</B>
+
+is a synonym for
+<B>0.0.0.0/0</B>
+
+or
+<B>::/0</B>
+
+in IPv4 or IPv6 respectively.
+<P>
+
+<I>Ttosubnet</I>
+
+ANDs the mask with the address before returning,
+so that any non-network bits in the address are turned off
+(e.g.,
+<B>10.1.2.3/24</B>
+
+is synonymous with
+<B>10.1.2.0/24</B>).
+
+<I>Subnettot</I>
+
+always generates the decimal-integer-bit-count
+form of the mask,
+with no leading zeros.
+<P>
+
+The
+<I>srclen</I>
+
+parameter of
+<I>ttoaddr</I>
+
+and
+<I>ttosubnet</I>
+
+specifies the length of the text string pointed to by
+<I>src</I>;
+
+it is an error for there to be anything else
+(e.g., a terminating NUL) within that length.
+As a convenience for cases where an entire NUL-terminated string is
+to be converted,
+a
+<I>srclen</I>
+
+value of
+<B>0</B>
+
+is taken to mean
+<B>strlen(src)</B>.
+
+<P>
+
+The
+<I>af</I>
+
+parameter of
+<I>ttoaddr</I>
+
+and
+<I>ttosubnet</I>
+
+specifies the address family of interest.
+It should be either
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>.
+
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of
+<I>addrtot</I>
+
+and
+<I>subnettot</I>
+
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+The
+<I>freeswan.h</I>
+
+header file defines constants,
+<B>ADDRTOT_BUF</B>
+
+and
+<B>SUBNETTOT_BUF</B>,
+
+which are the sizes of buffers just large enough for worst-case results.
+<P>
+
+The
+<I>format</I>
+
+parameter of
+<I>addrtot</I>
+
+and
+<I>subnettot</I>
+
+specifies what format is to be used for the conversion.
+The value
+<B>0</B>
+
+(not the character
+<B>'0'</B>,
+
+but a zero value)
+specifies a reasonable default,
+and is in fact the only format currently available in
+<I>subnettot</I>.
+
+<I>Addrtot</I>
+
+also accepts format values
+<B>'r'</B>
+
+(signifying a text form suitable for DNS reverse lookups,
+e.g.
+<B>4.3.2.1.IN-ADDR.ARPA.</B>
+
+for IPv4 and
+RFC 2874 format for IPv6),
+and
+<B>'R'</B>
+
+(signifying an alternate reverse-lookup form,
+an error for IPv4 and RFC 1886 format for IPv6).
+Reverse-lookup names always end with a ``.''.
+<P>
+
+The text-to-binary functions return NULL for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+The binary-to-text functions return
+<B>0</B>
+
+for a failure, and otherwise
+always return the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL;
+it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>ttoaddr</I>
+
+are:
+empty input;
+unknown address family;
+attempt to allocate temporary storage for a very long name failed;
+name lookup failed;
+syntax error in dotted-decimal or colon-hex form;
+dotted-decimal or colon-hex component too large.
+<P>
+
+Fatal errors in
+<I>ttosubnet</I>
+
+are:
+no
+<B>/</B>
+
+in
+<I>src</I>;
+
+<I>ttoaddr</I>
+
+error in conversion of
+<I>network</I>
+
+or
+<I>mask</I>;
+
+bit-count mask too big;
+mask non-contiguous.
+<P>
+
+Fatal errors in
+<I>addrtot</I>
+
+and
+<I>subnettot</I>
+
+are:
+unknown format.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+The interpretation of incomplete dotted-decimal addresses
+(e.g.
+<B>10/24</B>
+
+means
+<B>10.0.0.0/24</B>)
+
+differs from that of some older conversion
+functions, e.g. those of
+<I><A HREF="inet.3.html">inet</A></I>(3).
+
+The behavior of the older functions has never been
+particularly consistent or particularly useful.
+<P>
+
+Ignoring leading zeros in dotted-decimal components and bit counts
+is arguably the most useful behavior in this application,
+but it might occasionally cause confusion with the historical use of leading 
+zeros to denote octal numbers.
+<P>
+
+<I>Ttoaddr</I>
+
+does not support the mixed colon-hex-dotted-decimal
+convention used to embed an IPv4 address in an IPv6 address.
+<P>
+
+<I>Addrtot</I>
+
+always uses the
+<B>::</B>
+
+abbreviation (which can appear only once in an address) for the
+<I>first</I>
+
+sequence of multiple zeros in an IPv6 address.
+One can construct addresses (unlikely ones) in which this is suboptimal.
+<P>
+
+<I>Addrtot</I>
+
+<B>'r'</B>
+
+conversion of an IPv6 address uses lowercase hexadecimal,
+not the uppercase used in RFC 2874's examples.
+It takes careful reading of RFCs 2874, 2673, and 2234 to realize
+that lowercase is technically legitimate here,
+and there may be software which botches this
+and hence would have trouble with lowercase hex.
+<P>
+
+Possibly
+<I>subnettot</I>
+
+ought to recognize the
+<B>%default</B>
+
+case and generate that string as its output.
+Currently it doesn't.
+<P>
+
+It is barely possible that somebody, somewhere,
+might have a legitimate use for non-contiguous subnet masks.
+<P>
+
+<I><A HREF="Getnetbyname.3.html">Getnetbyname</A></I>(3)
+
+is a historical dreg.
+<P>
+
+<I>Tnatoaddr</I>
+
+probably should enforce completeness of dotted-decimal addresses.
+<P>
+
+The restriction of text-to-binary error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The text-to-binary error-reporting convention lends itself
+to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = ttoaddr( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
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new file mode 100644
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@@ -0,0 +1,439 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_TTODATA</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_TTODATA</H1>
+Section: C Library Functions (3)<BR>Updated: 16 August 2003<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec ttodata, datatot - convert binary data bytes from and to text formats
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *ttodata(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int base, char *dst, size_t dstlen, size_t *lenp);</B>
+
+<BR>
+
+<B>const char *ttodatav(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int base, char *dst, size_t dstlen, size_t *lenp,</B>
+
+<BR>
+&nbsp;
+<B>char *errp, size_t errlen, int flags);</B>
+
+<BR>
+
+<B>size_t datatot(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int format, char *dst, size_t dstlen);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Ttodata</I>,
+
+<I>ttodatav</I>,
+
+and
+<I>datatot</I>
+
+convert arbitrary binary data (e.g. encryption or authentication keys)
+from and to more-or-less human-readable text formats.
+<P>
+
+Currently supported formats are hexadecimal, base64, and characters.
+<P>
+
+A hexadecimal text value begins with a
+<B>0x</B>
+
+(or
+<B>0X</B>)
+
+prefix and continues with two-digit groups
+of hexadecimal digits (0-9, and a-f or A-F),
+each group encoding the value of one binary byte, high-order digit first.
+A single
+<B>_</B>
+
+(underscore)
+between consecutive groups is ignored, permitting punctuation to improve 
+readability; doing this every eight digits seems about right.
+<P>
+
+A base64 text value begins with a
+<B>0s</B>
+
+(or
+<B>0S</B>)
+
+prefix 
+and continues with four-digit groups of base64 digits (A-Z, a-z, 0-9, +, and /),
+each group encoding the value of three binary bytes as described in
+section 6.8 of RFC 2045.
+If
+<B>flags</B>
+
+has the
+<B>TTODATAV_IGNORESPACE</B>
+
+bit on, blanks are ignore (after the prefix).
+Note that the last one or two digits of a base64 group can be
+<B>=</B>
+
+to indicate that fewer than three binary bytes are encoded.
+<P>
+
+A character text value begins with a
+<B>0t</B>
+
+(or
+<B>0T</B>)
+
+prefix
+and continues with text characters, each being the value of one binary byte. 
+<P>
+
+All these functions basically copy data from
+<I>src</I>
+
+(whose size is specified by
+<I>srclen</I>)
+
+to
+<I>dst</I>
+
+(whose size is specified by
+<I>dstlen</I>),
+
+doing the conversion en route.
+If the result will not fit in
+<I>dst</I>,
+
+it is truncated;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes of result written to
+<I>dst</I>.
+
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result bytes are written at all.
+<P>
+
+The
+<I>base</I>
+
+parameter of
+<I>ttodata</I>
+
+and
+<I>ttodatav</I>
+
+specifies what format the input is in;
+normally it should be
+<B>0</B>
+
+to signify that this gets figured out from the prefix.
+Values of
+<B>16</B>,
+
+<B>64</B>,
+
+and
+<B>256</B>
+
+respectively signify hexadecimal, base64, and character-text formats
+without prefixes.
+<P>
+
+The
+<I>format</I>
+
+parameter of
+<I>datatot</I>,
+
+a single character used as a type code,
+specifies which text format is wanted.
+The value
+<B>0</B>
+
+(not ASCII
+<B>'0'</B>,
+
+but a zero value) specifies a reasonable default.
+Other currently-supported values are:
+<DL COMPACT><DT><DD>
+<DL COMPACT>
+<DT><B>'x'</B>
+
+<DD>
+continuous lower-case hexadecimal with a
+<B>0x</B>
+
+prefix
+<DT><B>'h'</B>
+
+<DD>
+lower-case hexadecimal with a
+<B>0x</B>
+
+prefix and a
+<B>_</B>
+
+every eight digits
+<DT><B>':'</B>
+
+<DD>
+lower-case hexadecimal with no prefix and a
+<B>:</B>
+
+(colon) every two digits
+<DT><B>16</B>
+
+<DD>
+lower-case hexadecimal with no prefix or
+<B>_</B>
+
+<DT><B>'s'</B>
+
+<DD>
+continuous base64 with a
+<B>0s</B>
+
+prefix
+<DT><B>64</B>
+
+<DD>
+continuous base64 with no prefix
+</DL>
+</DL>
+
+<P>
+
+The default format is currently
+<B>'h'</B>.
+
+<P>
+
+<I>Ttodata</I>
+
+returns NULL for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+On success,
+if and only if
+<I>lenp</I>
+
+is non-NULL,
+<B>*lenp</B>
+
+is set to the number of bytes required to contain the full untruncated result.
+It is the caller's responsibility to check this against
+<I>dstlen</I>
+
+to determine whether he has obtained a complete result.
+The
+<B>*lenp</B>
+
+value is correct even if
+<I>dstlen</I>
+
+is zero, which offers a way to determine how much space would be needed
+before having to allocate any.
+<P>
+
+<I>Ttodatav</I>
+
+is just like
+<I>ttodata</I>
+
+except that in certain cases,
+if
+<I>errp</I>
+
+is non-NULL,
+the buffer pointed to by
+<I>errp</I>
+
+(whose length is given by
+<I>errlen</I>)
+
+is used to hold a more detailed error message.
+The return value is NULL for success,
+and is either
+<I>errp</I>
+
+or a pointer to a string literal for failure.
+If the size of the error-message buffer is
+inadequate for the desired message,
+<I>ttodatav</I>
+
+will fall back on returning a pointer to a literal string instead.
+The
+<I>freeswan.h</I>
+
+header file defines a constant
+<B>TTODATAV_BUF</B>
+
+which is the size of a buffer large enough for worst-case results.
+<P>
+
+The normal return value of
+<I>datatot</I>
+
+is the number of bytes required
+to contain the full untruncated result.
+It is the caller's responsibility to check this against
+<I>dstlen</I>
+
+to determine whether he has obtained a complete result.
+The return value is correct even if
+<I>dstlen</I>
+
+is zero, which offers a way to determine how much space would be needed
+before having to allocate any.
+A return value of
+<B>0</B>
+
+signals a fatal error of some kind
+(see DIAGNOSTICS).
+<P>
+
+A zero value for
+<I>srclen</I>
+
+in
+<I>ttodata</I>
+
+(but not
+<I>datatot</I>!)
+
+is synonymous with
+<B>strlen(src)</B>.
+
+A non-zero
+<I>srclen</I>
+
+in
+<I>ttodata</I>
+
+must not include the terminating NUL.
+<P>
+
+Unless
+<I>dstlen</I>
+
+is zero,
+the result supplied by
+<I>datatot</I>
+
+is always NUL-terminated,
+and its needed-size return value includes space for the terminating NUL.
+<P>
+
+Several obsolete variants of these functions
+(<I>atodata</I>,
+
+<I>datatoa</I>,
+
+<I>atobytes</I>,
+
+and
+<I>bytestoa</I>)
+
+are temporarily also supported.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="sprintf.3.html">sprintf</A>(3), <A HREF="ipsec_atoaddr.3.html">ipsec_atoaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>ttodata</I>
+
+and
+<I>ttodatav</I>
+
+are:
+unknown characters in the input;
+unknown or missing prefix;
+unknown base;
+incomplete digit group;
+non-zero padding in a base64 less-than-three-bytes digit group;
+zero-length input.
+<P>
+
+Fatal errors in
+<I>datatot</I>
+
+are:
+unknown format code;
+zero-length input.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+<I>Datatot</I>
+
+should have a format code to produce character-text output.
+<P>
+
+The
+<B>0s</B>
+
+and
+<B>0t</B>
+
+prefixes are the author's inventions and are not a standard
+of any kind.
+They have been chosen to avoid collisions with existing practice
+(some C implementations use
+<B>0b</B>
+
+for binary)
+and possible confusion with unprefixed hexadecimal.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_ttosa.3.html b/doc/manpage.d/ipsec_ttosa.3.html
new file mode 100644
index 000000000..1e457fc24
--- /dev/null
+++ b/doc/manpage.d/ipsec_ttosa.3.html
@@ -0,0 +1,453 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_TTOSA</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_TTOSA</H1>
+Section: C Library Functions (3)<BR>Updated: 26 Nov 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec ttosa, satot - convert IPsec Security Association IDs to and from text
+<BR>
+
+ipsec initsaid - initialize an SA ID
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>typedef struct {</B>
+
+<BR>
+&nbsp;
+<B>ip_address dst;</B>
+
+<BR>
+&nbsp;
+<B>ipsec_spi_t spi;</B>
+
+<BR>
+&nbsp;
+<B>int proto;</B>
+
+<BR>
+
+<B>} ip_said;</B>
+
+<P>
+<B>const char *ttosa(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>ip_said *sa);</B>
+
+<BR>
+
+<B>size_t satot(const ip_said *sa, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<BR>
+
+<B>void initsaid(const ip_address *addr, ipsec_spi_t spi,</B>
+
+<BR>
+&nbsp;
+<B>int proto, ip_said *dst);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Ttosa</I>
+
+converts an ASCII Security Association (SA) specifier into an
+<B>ip_said</B>
+
+structure (containing
+a destination-host address
+in network byte order,
+an SPI number in network byte order, and
+a protocol code).
+<I>Satot</I>
+
+does the reverse conversion, back to a text SA specifier.
+<I>Initsaid</I>
+
+initializes an
+<B>ip_said</B>
+
+from separate items of information.
+<P>
+
+An SA is specified in text with a mail-like syntax, e.g.
+<B><A HREF="mailto:esp.5a7@1.2.3.4">esp.5a7@1.2.3.4</A></B>.
+
+An SA specifier contains
+a protocol prefix (currently
+<B>ah</B>,
+
+<B>esp</B>,
+
+<B>tun</B>,
+
+<B>comp</B>,
+
+or
+<B>int</B>),
+
+a single character indicating the address family
+(<B>.</B>
+
+for IPv4,
+<B>:</B>
+
+for IPv6),
+an unsigned integer SPI number in hexadecimal (with no
+<B>0x</B>
+
+prefix),
+and an IP address.
+The IP address can be any form accepted by
+<I><A HREF="ipsec_ttoaddr.3.html">ipsec_ttoaddr</A></I>(3),
+
+e.g. dotted-decimal IPv4 address,
+colon-hex IPv6 address,
+or DNS name.
+<P>
+
+As a special case, the SA specifier
+<B>%passthrough4</B>
+
+or
+<B>%passthrough6</B>
+
+signifies the special SA used to indicate that packets should be
+passed through unaltered.
+(At present, these are synonyms for
+<B><A HREF="mailto:tun.0@0.0.0.0">tun.0@0.0.0.0</A></B>
+
+and
+<B>tun:0@::</B>
+
+respectively,
+but that is subject to change without notice.)
+<B>%passthrough</B>
+
+is a historical synonym for
+<B>%passthrough4</B>.
+
+These forms are known to both
+<I>ttosa</I>
+
+and
+<I>satot</I>,
+
+so the internal representation is never visible.
+<P>
+
+Similarly, the SA specifiers
+<B>%pass</B>,
+
+<B>%drop</B>,
+
+<B>%reject</B>,
+
+<B>%hold</B>,
+
+<B>%trap</B>,
+
+and
+<B>%trapsubnet</B>
+
+signify special ``magic'' SAs used to indicate that packets should be
+passed, dropped, rejected (dropped with ICMP notification),
+held,
+and trapped (sent up to
+<I><A HREF="ipsec_pluto.8.html">ipsec_pluto</A></I>(8),
+
+with either of two forms of
+<B>%hold</B>
+
+automatically installed)
+respectively.
+These forms too are known to both routines,
+so the internal representation of the magic SAs should never be visible.
+<P>
+
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file supplies the
+<B>ip_said</B>
+
+structure, as well as a data type
+<B>ipsec_spi_t</B>
+
+which is an unsigned 32-bit integer.
+(There is no consistency between kernel and user on what such a type
+is called, hence the header hides the differences.)
+<P>
+
+The protocol code uses the same numbers that IP does.
+For user convenience, given the difficulty in acquiring the exact set of
+protocol names used by the kernel,
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+defines the names
+<B>SA_ESP</B>,
+
+<B>SA_AH</B>,
+
+<B>SA_IPIP</B>,
+
+and
+<B>SA_COMP</B>
+
+to have the same values as the kernel names
+<B>IPPROTO_ESP</B>,
+
+<B>IPPROTO_AH</B>,
+
+<B>IPPROTO_IPIP</B>,
+
+and
+<B>IPPROTO_COMP</B>.
+
+<P>
+
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+also defines
+<B>SA_INT</B>
+
+to have the value
+<B>61</B>
+
+(reserved by IANA for ``any host internal protocol'')
+and
+<B>SPI_PASS</B>,
+
+<B>SPI_DROP</B>,
+
+<B>SPI_REJECT</B>,
+
+<B>SPI_HOLD</B>,
+
+and
+<B>SPI_TRAP</B>
+
+to have the values 256-260 (in <I>host</I> byte order) respectively.
+These are used in constructing the magic SAs
+(which always have address
+<B>0.0.0.0</B>).
+
+<P>
+
+If
+<I>satot</I>
+
+encounters an unknown protocol code, e.g. 77,
+it yields output using a prefix
+showing the code numerically, e.g. ``unk77''.
+This form is
+<I>not</I>
+
+recognized by
+<I>ttosa</I>.
+
+<P>
+
+The
+<I>srclen</I>
+
+parameter of
+<I>ttosa</I>
+
+specifies the length of the string pointed to by
+<I>src</I>;
+
+it is an error for there to be anything else
+(e.g., a terminating NUL) within that length.
+As a convenience for cases where an entire NUL-terminated string is
+to be converted,
+a
+<I>srclen</I>
+
+value of
+<B>0</B>
+
+is taken to mean
+<B>strlen(src)</B>.
+
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of
+<I>satot</I>
+
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+The
+<B>&lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+header file defines a constant,
+<B>SATOT_BUF</B>,
+
+which is the size of a buffer just large enough for worst-case results.
+<P>
+
+The
+<I>format</I>
+
+parameter of
+<I>satot</I>
+
+specifies what format is to be used for the conversion.
+The value
+<B>0</B>
+
+(not the ASCII character
+<B>'0'</B>,
+
+but a zero value)
+specifies a reasonable default
+(currently
+lowercase protocol prefix, lowercase hexadecimal SPI,
+dotted-decimal or colon-hex address).
+The value
+<B>'f'</B>
+
+is similar except that the SPI is padded with
+<B>0</B>s
+
+to a fixed 32-bit width, to ease aligning displayed tables.
+<P>
+
+<I>Ttosa</I>
+
+returns
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<I>Satot</I>
+
+returns
+<B>0</B>
+
+for a failure, and otherwise
+always returns the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL;
+it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred.
+<P>
+
+There is also, temporarily, support for some obsolete
+forms of SA specifier which lack the address-family indicator.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec_ttoul.3.html">ipsec_ttoul</A>(3), <A HREF="ipsec_ttoaddr.3.html">ipsec_ttoaddr</A>(3), <A HREF="ipsec_samesaid.3.html">ipsec_samesaid</A>(3), <A HREF="inet.3.html">inet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>ttosa</I>
+
+are:
+empty input;
+input too small to be a legal SA specifier;
+no
+<B>@</B>
+
+in input;
+unknown protocol prefix;
+conversion error in
+<I>ttoul</I>
+
+or
+<I>ttoaddr</I>.
+
+<P>
+
+Fatal errors in
+<I>satot</I>
+
+are:
+unknown format.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+The restriction of text-to-binary error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The text-to-binary error-reporting convention lends itself
+to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = ttosa( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_ttosubnet.3.html b/doc/manpage.d/ipsec_ttosubnet.3.html
new file mode 100644
index 000000000..199937a35
--- /dev/null
+++ b/doc/manpage.d/ipsec_ttosubnet.3.html
@@ -0,0 +1,569 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_TTOADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_TTOADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 28 Sept 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec ttoaddr, tnatoaddr, addrtot - convert Internet addresses to and from text
+<BR>
+
+ipsec ttosubnet, subnettot - convert subnet/mask text form to and from addresses
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *ttoaddr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int af, ip_address *addr);</B>
+
+<BR>
+
+<B>const char *tnatoaddr(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int af, ip_address *addr);</B>
+
+<BR>
+
+<B>size_t addrtot(const ip_address *addr, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<P>
+<B>const char *ttosubnet(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int af, ip_subnet *dst);</B>
+
+<BR>
+
+<B>size_t subnettot(const ip_subnet *sub, int format,</B>
+
+<BR>
+&nbsp;
+<B>char *dst, size_t dstlen);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Ttoaddr</I>
+
+converts a text-string name or numeric address into a binary address
+(in network byte order).
+<I>Tnatoaddr</I>
+
+does the same conversion,
+but the only text forms it accepts are
+the ``official'' forms of
+numeric address (dotted-decimal for IPv4, colon-hex for IPv6).
+<I>Addrtot</I>
+
+does the reverse conversion, from binary address back to a text form.
+<I>Ttosubnet</I>
+
+and
+<I>subnettot</I>
+
+do likewise for the ``address/mask'' form used to write a
+specification of a subnet.
+<P>
+
+An IPv4 address is specified in text as a
+dotted-decimal address (e.g.
+<B>1.2.3.4</B>),
+
+an eight-digit network-order hexadecimal number with the usual C prefix (e.g.
+<B>0x01020304</B>,
+
+which is synonymous with
+<B>1.2.3.4</B>),
+
+an eight-digit host-order hexadecimal number with a
+<B>0h</B>
+
+prefix (e.g.
+<B>0h01020304</B>,
+
+which is synonymous with
+<B>1.2.3.4</B>
+
+on a big-endian host and
+<B>4.3.2.1</B>
+
+on a little-endian host),
+a DNS name to be looked up via
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3),
+
+or an old-style network name to be looked up via
+<I><A HREF="getnetbyname.3.html">getnetbyname</A></I>(3).
+
+<P>
+
+A dotted-decimal address may be incomplete, in which case
+text-to-binary conversion implicitly appends
+as many instances of
+<B>.0</B>
+
+as necessary to bring it up to four components.
+The components of a dotted-decimal address are always taken as
+decimal, and leading zeros are ignored.
+For example,
+<B>10</B>
+
+is synonymous with
+<B>10.0.0.0</B>,
+
+and
+<B>128.009.000.032</B>
+
+is synonymous with
+<B>128.9.0.32</B>
+
+(the latter example is verbatim from RFC 1166).
+The result of applying
+<I>addrtot</I>
+
+to an IPv4 address is always complete and does not contain leading zeros.
+<P>
+
+Use of hexadecimal addresses is
+<B>strongly</B>
+
+<B>discouraged</B>;
+
+they are included only to save hassles when dealing with
+the handful of perverted programs which already print 
+network addresses in hexadecimal.
+<P>
+
+An IPv6 address is specified in text with
+colon-hex notation (e.g.
+<B>0:56:78ab:22:33:44:55:66</B>),
+
+colon-hex with
+<B>::</B>
+
+abbreviating at most one subsequence of multiple zeros (e.g.
+<B>99:ab::54:068</B>,
+
+which is synonymous with
+<B>99:ab:0:0:0:0:54:68</B>),
+
+or a DNS name to be looked up via
+<I><A HREF="gethostbyname.3.html">gethostbyname</A></I>(3).
+
+The result of applying
+<I>addrtot</I>
+
+to an IPv6 address will use
+<B>::</B>
+
+abbreviation if possible,
+and will not contain leading zeros.
+<P>
+
+The letters in hexadecimal
+may be uppercase or lowercase or any mixture thereof.
+<P>
+
+DNS names may be complete (optionally terminated with a ``.'')
+or incomplete, and are looked up as specified by local system configuration
+(see
+<I><A HREF="resolver.5.html">resolver</A></I>(5)).
+
+The
+<I>h_addr</I>
+
+value returned by
+<I><A HREF="gethostbyname2.3.html">gethostbyname2</A></I>(3)
+
+is used,
+so with current DNS implementations,
+the result when the name corresponds to more than one address is
+difficult to predict.
+IPv4 name lookup resorts to
+<I><A HREF="getnetbyname.3.html">getnetbyname</A></I>(3)
+
+only if
+<I><A HREF="gethostbyname2.3.html">gethostbyname2</A></I>(3)
+
+fails.
+<P>
+
+A subnet specification is of the form <I>network</I><B>/</B><I>mask</I>.
+The
+<I>network</I>
+
+and
+<I>mask</I>
+
+can be any form acceptable to
+<I>ttoaddr</I>.
+
+In addition, and preferably, the
+<I>mask</I>
+
+can be a decimal integer (leading zeros ignored) giving a bit count,
+in which case
+it stands for a mask with that number of high bits on and all others off
+(e.g.,
+<B>24</B>
+
+in IPv4 means
+<B>255.255.255.0</B>).
+
+In any case, the mask must be contiguous
+(a sequence of high bits on and all remaining low bits off).
+As a special case, the subnet specification
+<B>%default</B>
+
+is a synonym for
+<B>0.0.0.0/0</B>
+
+or
+<B>::/0</B>
+
+in IPv4 or IPv6 respectively.
+<P>
+
+<I>Ttosubnet</I>
+
+ANDs the mask with the address before returning,
+so that any non-network bits in the address are turned off
+(e.g.,
+<B>10.1.2.3/24</B>
+
+is synonymous with
+<B>10.1.2.0/24</B>).
+
+<I>Subnettot</I>
+
+always generates the decimal-integer-bit-count
+form of the mask,
+with no leading zeros.
+<P>
+
+The
+<I>srclen</I>
+
+parameter of
+<I>ttoaddr</I>
+
+and
+<I>ttosubnet</I>
+
+specifies the length of the text string pointed to by
+<I>src</I>;
+
+it is an error for there to be anything else
+(e.g., a terminating NUL) within that length.
+As a convenience for cases where an entire NUL-terminated string is
+to be converted,
+a
+<I>srclen</I>
+
+value of
+<B>0</B>
+
+is taken to mean
+<B>strlen(src)</B>.
+
+<P>
+
+The
+<I>af</I>
+
+parameter of
+<I>ttoaddr</I>
+
+and
+<I>ttosubnet</I>
+
+specifies the address family of interest.
+It should be either
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>.
+
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of
+<I>addrtot</I>
+
+and
+<I>subnettot</I>
+
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+The
+<I>freeswan.h</I>
+
+header file defines constants,
+<B>ADDRTOT_BUF</B>
+
+and
+<B>SUBNETTOT_BUF</B>,
+
+which are the sizes of buffers just large enough for worst-case results.
+<P>
+
+The
+<I>format</I>
+
+parameter of
+<I>addrtot</I>
+
+and
+<I>subnettot</I>
+
+specifies what format is to be used for the conversion.
+The value
+<B>0</B>
+
+(not the character
+<B>'0'</B>,
+
+but a zero value)
+specifies a reasonable default,
+and is in fact the only format currently available in
+<I>subnettot</I>.
+
+<I>Addrtot</I>
+
+also accepts format values
+<B>'r'</B>
+
+(signifying a text form suitable for DNS reverse lookups,
+e.g.
+<B>4.3.2.1.IN-ADDR.ARPA.</B>
+
+for IPv4 and
+RFC 2874 format for IPv6),
+and
+<B>'R'</B>
+
+(signifying an alternate reverse-lookup form,
+an error for IPv4 and RFC 1886 format for IPv6).
+Reverse-lookup names always end with a ``.''.
+<P>
+
+The text-to-binary functions return NULL for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+The binary-to-text functions return
+<B>0</B>
+
+for a failure, and otherwise
+always return the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL;
+it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>ttoaddr</I>
+
+are:
+empty input;
+unknown address family;
+attempt to allocate temporary storage for a very long name failed;
+name lookup failed;
+syntax error in dotted-decimal or colon-hex form;
+dotted-decimal or colon-hex component too large.
+<P>
+
+Fatal errors in
+<I>ttosubnet</I>
+
+are:
+no
+<B>/</B>
+
+in
+<I>src</I>;
+
+<I>ttoaddr</I>
+
+error in conversion of
+<I>network</I>
+
+or
+<I>mask</I>;
+
+bit-count mask too big;
+mask non-contiguous.
+<P>
+
+Fatal errors in
+<I>addrtot</I>
+
+and
+<I>subnettot</I>
+
+are:
+unknown format.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+The interpretation of incomplete dotted-decimal addresses
+(e.g.
+<B>10/24</B>
+
+means
+<B>10.0.0.0/24</B>)
+
+differs from that of some older conversion
+functions, e.g. those of
+<I><A HREF="inet.3.html">inet</A></I>(3).
+
+The behavior of the older functions has never been
+particularly consistent or particularly useful.
+<P>
+
+Ignoring leading zeros in dotted-decimal components and bit counts
+is arguably the most useful behavior in this application,
+but it might occasionally cause confusion with the historical use of leading 
+zeros to denote octal numbers.
+<P>
+
+<I>Ttoaddr</I>
+
+does not support the mixed colon-hex-dotted-decimal
+convention used to embed an IPv4 address in an IPv6 address.
+<P>
+
+<I>Addrtot</I>
+
+always uses the
+<B>::</B>
+
+abbreviation (which can appear only once in an address) for the
+<I>first</I>
+
+sequence of multiple zeros in an IPv6 address.
+One can construct addresses (unlikely ones) in which this is suboptimal.
+<P>
+
+<I>Addrtot</I>
+
+<B>'r'</B>
+
+conversion of an IPv6 address uses lowercase hexadecimal,
+not the uppercase used in RFC 2874's examples.
+It takes careful reading of RFCs 2874, 2673, and 2234 to realize
+that lowercase is technically legitimate here,
+and there may be software which botches this
+and hence would have trouble with lowercase hex.
+<P>
+
+Possibly
+<I>subnettot</I>
+
+ought to recognize the
+<B>%default</B>
+
+case and generate that string as its output.
+Currently it doesn't.
+<P>
+
+It is barely possible that somebody, somewhere,
+might have a legitimate use for non-contiguous subnet masks.
+<P>
+
+<I><A HREF="Getnetbyname.3.html">Getnetbyname</A></I>(3)
+
+is a historical dreg.
+<P>
+
+<I>Tnatoaddr</I>
+
+probably should enforce completeness of dotted-decimal addresses.
+<P>
+
+The restriction of text-to-binary error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The text-to-binary error-reporting convention lends itself
+to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = ttoaddr( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_ttoul.3.html b/doc/manpage.d/ipsec_ttoul.3.html
new file mode 100644
index 000000000..b722dcc13
--- /dev/null
+++ b/doc/manpage.d/ipsec_ttoul.3.html
@@ -0,0 +1,310 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_TTOUL</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_TTOUL</H1>
+Section: C Library Functions (3)<BR>Updated: 16 Aug 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec ttoul, ultot - convert unsigned-long numbers to and from text
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *ttoul(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int base, unsigned long *n);</B>
+
+<BR>
+
+<B>size_t ultot(unsigned long n, int format, char *dst,</B>
+
+<BR>
+&nbsp;
+<B>size_t dstlen);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Ttoul</I>
+
+converts a text-string number into a binary
+<B>unsigned long</B>
+
+value.
+<I>Ultot</I>
+
+does the reverse conversion, back to a text version.
+<P>
+
+Numbers are specified in text as
+decimal (e.g.
+<B>123</B>),
+
+octal with a leading zero (e.g.
+<B>012</B>,
+
+which has value 10),
+or hexadecimal with a leading
+<B>0x</B>
+
+(e.g.
+<B>0x1f</B>,
+
+which has value 31)
+in either upper or lower case.
+<P>
+
+The
+<I>srclen</I>
+
+parameter of
+<I>ttoul</I>
+
+specifies the length of the string pointed to by
+<I>src</I>;
+
+it is an error for there to be anything else
+(e.g., a terminating NUL) within that length.
+As a convenience for cases where an entire NUL-terminated string is
+to be converted,
+a
+<I>srclen</I>
+
+value of
+<B>0</B>
+
+is taken to mean
+<B>strlen(src)</B>.
+
+<P>
+
+The
+<I>base</I>
+
+parameter of
+<I>ttoul</I>
+
+can be
+<B>8</B>,
+
+<B>10</B>,
+
+or
+<B>16</B>,
+
+in which case the number supplied is assumed to be of that form
+(and in the case of
+<B>16</B>,
+
+to lack any
+<B>0x</B>
+
+prefix).
+It can also be
+<B>0</B>,
+
+in which case the number is examined for a leading zero
+or a leading
+<B>0x</B>
+
+to determine its base.
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of
+<I>ultot</I>
+
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+The
+<I>freeswan.h</I>
+
+header file defines a constant,
+<B>ULTOT_BUF</B>,
+
+which is the size of a buffer just large enough for worst-case results.
+<P>
+
+The
+<I>format</I>
+
+parameter of
+<I>ultot</I>
+
+must be one of:
+<DL COMPACT><DT><DD>
+<DL COMPACT>
+<DT><B>'o'</B><DD>
+octal conversion with leading
+<B>0</B>
+
+<DT><B>&nbsp;8</B><DD>
+octal conversion with no leading
+<B>0</B>
+
+<DT><B>'d'</B><DD>
+decimal conversion
+<DT><B>10</B><DD>
+same as
+<B>d</B>
+
+<DT><B>'x'</B><DD>
+hexadecimal conversion, including leading
+<B>0x</B>
+
+<DT><B>16</B><DD>
+hexadecimal conversion with no leading
+<B>0x</B>
+
+<DT><B>17</B><DD>
+like
+<B>16</B>
+
+except padded on left with
+<B>0</B>s
+
+to eight digits (full width of a 32-bit number)
+</DL>
+</DL>
+
+<P>
+
+<I>Ttoul</I>
+
+returns NULL for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<I>Ultot</I>
+
+returns
+<B>0</B>
+
+for a failure, and otherwise
+returns the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL
+(it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred).
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="atol.3.html">atol</A>(3), <A HREF="strtoul.3.html">strtoul</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>ttoul</I>
+
+are:
+empty input;
+unknown
+<I>base</I>;
+
+non-digit character found;
+number too large for an
+<B>unsigned long</B>.
+
+<P>
+
+Fatal errors in
+<I>ultot</I>
+
+are:
+unknown
+<I>format</I>.
+
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+Conversion of
+<B>0</B>
+
+with format
+<B>o</B>
+
+yields
+<B>00</B>.
+
+<P>
+
+<I>Ultot</I>
+
+format
+<B>17</B>
+
+is a bit of a kludge.
+<P>
+
+The restriction of error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The error-reporting convention lends itself to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = ttoul( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_ultoa.3.html b/doc/manpage.d/ipsec_ultoa.3.html
new file mode 100644
index 000000000..7669dce52
--- /dev/null
+++ b/doc/manpage.d/ipsec_ultoa.3.html
@@ -0,0 +1,266 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ATOUL</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ATOUL</H1>
+Section: C Library Functions (3)<BR>Updated: 11 June 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec atoul, ultoa - convert unsigned-long numbers to and from ASCII
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *atoul(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int base, unsigned long *n);</B>
+
+<BR>
+
+<B>size_t ultoa(unsigned long n, int base, char *dst,</B>
+
+<BR>
+&nbsp;
+<B>size_t dstlen);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions are obsolete; see
+<I><A HREF="ipsec_ttoul.3.html">ipsec_ttoul</A></I>(3)
+
+for their replacements.
+<P>
+
+<I>Atoul</I>
+
+converts an ASCII number into a binary
+<B>unsigned long</B>
+
+value.
+<I>Ultoa</I>
+
+does the reverse conversion, back to an ASCII version.
+<P>
+
+Numbers are specified in ASCII as
+decimal (e.g.
+<B>123</B>),
+
+octal with a leading zero (e.g.
+<B>012</B>,
+
+which has value 10),
+or hexadecimal with a leading
+<B>0x</B>
+
+(e.g.
+<B>0x1f</B>,
+
+which has value 31)
+in either upper or lower case.
+<P>
+
+The
+<I>srclen</I>
+
+parameter of
+<I>atoul</I>
+
+specifies the length of the ASCII string pointed to by
+<I>src</I>;
+
+it is an error for there to be anything else
+(e.g., a terminating NUL) within that length.
+As a convenience for cases where an entire NUL-terminated string is
+to be converted,
+a
+<I>srclen</I>
+
+value of
+<B>0</B>
+
+is taken to mean
+<B>strlen(src)</B>.
+
+<P>
+
+The
+<I>base</I>
+
+parameter of
+<I>atoul</I>
+
+can be
+<B>8</B>,
+
+<B>10</B>,
+
+or
+<B>16</B>,
+
+in which case the number supplied is assumed to be of that form
+(and in the case of
+<B>16</B>,
+
+to lack any
+<B>0x</B>
+
+prefix).
+It can also be
+<B>0</B>,
+
+in which case the number is examined for a leading zero
+or a leading
+<B>0x</B>
+
+to determine its base,
+or
+<B>13</B>
+
+(halfway between 10 and 16),
+which has the same effect as
+<B>0</B>
+
+except that a non-hexadecimal
+number is considered decimal regardless of any leading zero.
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of
+<I>ultoa</I>
+
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+<P>
+
+The
+<I>base</I>
+
+parameter of
+<I>ultoa</I>
+
+must be
+<B>8</B>,
+
+<B>10</B>,
+
+or
+<B>16</B>.
+
+<P>
+
+<I>Atoul</I>
+
+returns NULL for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<I>Ultoa</I>
+
+returns the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL;
+it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="atol.3.html">atol</A>(3), <A HREF="strtoul.3.html">strtoul</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>atoul</I>
+
+are:
+empty input;
+unknown
+<I>base</I>;
+
+non-digit character found;
+number too large for an
+<B>unsigned long</B>.
+
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+There is no provision for reporting an invalid
+<I>base</I>
+
+parameter given to
+<I>ultoa</I>.
+
+<P>
+
+The restriction of error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The error-reporting convention lends itself to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = atoul( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_ultot.3.html b/doc/manpage.d/ipsec_ultot.3.html
new file mode 100644
index 000000000..b722dcc13
--- /dev/null
+++ b/doc/manpage.d/ipsec_ultot.3.html
@@ -0,0 +1,310 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_TTOUL</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_TTOUL</H1>
+Section: C Library Functions (3)<BR>Updated: 16 Aug 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec ttoul, ultot - convert unsigned-long numbers to and from text
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *ttoul(const char *src, size_t srclen,</B>
+
+<BR>
+&nbsp;
+<B>int base, unsigned long *n);</B>
+
+<BR>
+
+<B>size_t ultot(unsigned long n, int format, char *dst,</B>
+
+<BR>
+&nbsp;
+<B>size_t dstlen);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>Ttoul</I>
+
+converts a text-string number into a binary
+<B>unsigned long</B>
+
+value.
+<I>Ultot</I>
+
+does the reverse conversion, back to a text version.
+<P>
+
+Numbers are specified in text as
+decimal (e.g.
+<B>123</B>),
+
+octal with a leading zero (e.g.
+<B>012</B>,
+
+which has value 10),
+or hexadecimal with a leading
+<B>0x</B>
+
+(e.g.
+<B>0x1f</B>,
+
+which has value 31)
+in either upper or lower case.
+<P>
+
+The
+<I>srclen</I>
+
+parameter of
+<I>ttoul</I>
+
+specifies the length of the string pointed to by
+<I>src</I>;
+
+it is an error for there to be anything else
+(e.g., a terminating NUL) within that length.
+As a convenience for cases where an entire NUL-terminated string is
+to be converted,
+a
+<I>srclen</I>
+
+value of
+<B>0</B>
+
+is taken to mean
+<B>strlen(src)</B>.
+
+<P>
+
+The
+<I>base</I>
+
+parameter of
+<I>ttoul</I>
+
+can be
+<B>8</B>,
+
+<B>10</B>,
+
+or
+<B>16</B>,
+
+in which case the number supplied is assumed to be of that form
+(and in the case of
+<B>16</B>,
+
+to lack any
+<B>0x</B>
+
+prefix).
+It can also be
+<B>0</B>,
+
+in which case the number is examined for a leading zero
+or a leading
+<B>0x</B>
+
+to determine its base.
+<P>
+
+The
+<I>dstlen</I>
+
+parameter of
+<I>ultot</I>
+
+specifies the size of the
+<I>dst</I>
+
+parameter;
+under no circumstances are more than
+<I>dstlen</I>
+
+bytes written to
+<I>dst</I>.
+
+A result which will not fit is truncated.
+<I>Dstlen</I>
+
+can be zero, in which case
+<I>dst</I>
+
+need not be valid and no result is written,
+but the return value is unaffected;
+in all other cases, the (possibly truncated) result is NUL-terminated.
+The
+<I>freeswan.h</I>
+
+header file defines a constant,
+<B>ULTOT_BUF</B>,
+
+which is the size of a buffer just large enough for worst-case results.
+<P>
+
+The
+<I>format</I>
+
+parameter of
+<I>ultot</I>
+
+must be one of:
+<DL COMPACT><DT><DD>
+<DL COMPACT>
+<DT><B>'o'</B><DD>
+octal conversion with leading
+<B>0</B>
+
+<DT><B>&nbsp;8</B><DD>
+octal conversion with no leading
+<B>0</B>
+
+<DT><B>'d'</B><DD>
+decimal conversion
+<DT><B>10</B><DD>
+same as
+<B>d</B>
+
+<DT><B>'x'</B><DD>
+hexadecimal conversion, including leading
+<B>0x</B>
+
+<DT><B>16</B><DD>
+hexadecimal conversion with no leading
+<B>0x</B>
+
+<DT><B>17</B><DD>
+like
+<B>16</B>
+
+except padded on left with
+<B>0</B>s
+
+to eight digits (full width of a 32-bit number)
+</DL>
+</DL>
+
+<P>
+
+<I>Ttoul</I>
+
+returns NULL for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<I>Ultot</I>
+
+returns
+<B>0</B>
+
+for a failure, and otherwise
+returns the size of buffer which would 
+be needed to
+accommodate the full conversion result, including terminating NUL
+(it is the caller's responsibility to check this against the size of
+the provided buffer to determine whether truncation has occurred).
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="atol.3.html">atol</A>(3), <A HREF="strtoul.3.html">strtoul</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in
+<I>ttoul</I>
+
+are:
+empty input;
+unknown
+<I>base</I>;
+
+non-digit character found;
+number too large for an
+<B>unsigned long</B>.
+
+<P>
+
+Fatal errors in
+<I>ultot</I>
+
+are:
+unknown
+<I>format</I>.
+
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<A NAME="lbAH">&nbsp;</A>
+<H2>BUGS</H2>
+
+Conversion of
+<B>0</B>
+
+with format
+<B>o</B>
+
+yields
+<B>00</B>.
+
+<P>
+
+<I>Ultot</I>
+
+format
+<B>17</B>
+
+is a bit of a kludge.
+<P>
+
+The restriction of error reports to literal strings
+(so that callers don't need to worry about freeing them or copying them)
+does limit the precision of error reporting.
+<P>
+
+The error-reporting convention lends itself to slightly obscure code,
+because many readers will not think of NULL as signifying success.
+A good way to make it clearer is to write something like:
+<P>
+
+<DL COMPACT><DT><DD>
+<PRE>
+<B>const char *error;</B>
+
+<B>error = ttoul( /* ... */ );</B>
+<B>if (error != NULL) {</B>
+<B>        /* something went wrong */</B>
+</PRE>
+
+</DL>
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+<DT><A HREF="#lbAH">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_unspecaddr.3.html b/doc/manpage.d/ipsec_unspecaddr.3.html
new file mode 100644
index 000000000..92f69d99c
--- /dev/null
+++ b/doc/manpage.d/ipsec_unspecaddr.3.html
@@ -0,0 +1,166 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_ANYADDR</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_ANYADDR</H1>
+Section: C Library Functions (3)<BR>Updated: 8 Sept 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec anyaddr - get &quot;any&quot; address
+<BR>
+
+ipsec isanyaddr - test address for equality to &quot;any&quot; address
+<BR>
+
+ipsec unspecaddr - get &quot;unspecified&quot; address
+<BR>
+
+ipsec isunspecaddr - test address for equality to &quot;unspecified&quot; address
+<BR>
+
+ipsec loopbackaddr - get loopback address
+<BR>
+
+ipsec isloopbackaddr - test address for equality to loopback address
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *anyaddr(int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int isanyaddr(const ip_address *src);</B>
+
+<BR>
+
+<B>const char *unspecaddr(int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int isunspecaddr(const ip_address *src);</B>
+
+<BR>
+
+<B>const char *loopbackaddr(int af, ip_address *dst);</B>
+
+<BR>
+
+<B>int isloopbackaddr(const ip_address *src);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions fill in, and test for, special values of the
+<I>ip_address</I>
+
+type.
+<P>
+
+<I>Anyaddr</I>
+
+fills in the destination
+<I>*dst</I>
+
+with the ``any'' address of address family
+<I>af</I>
+
+(normally
+<B>AF_INET</B>
+
+or
+<B>AF_INET6</B>).
+
+The IPv4 ``any'' address is the one embodied in the old
+<B>INADDR_ANY</B>
+
+macro.
+<P>
+
+<I>Isanyaddr</I>
+
+returns
+<B>1</B>
+
+if the
+<I>src</I>
+
+address equals the ``any'' address,
+and
+<B>0</B>
+
+otherwise.
+<P>
+
+Similarly,
+<I>unspecaddr</I>
+
+supplies, and
+<I>isunspecaddr</I>
+
+tests for,
+the ``unspecified'' address,
+which may be the same as the ``any'' address.
+<P>
+
+Similarly,
+<I>loopbackaddr</I>
+
+supplies, and
+<I>islookbackaddr</I>
+
+tests for,
+the loopback address.
+<P>
+
+<I>Anyaddr</I>,
+
+<I>unspecaddr</I>,
+
+and
+<I>loopbackaddr</I>
+
+return
+<B>NULL</B>
+
+for success and
+a pointer to a string-literal error message for failure;
+see DIAGNOSTICS.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="inet.3.html">inet</A>(3), <A HREF="ipsec_addrtot.3.html">ipsec_addrtot</A>(3), <A HREF="ipsec_sameaddr.3.html">ipsec_sameaddr</A>(3)
+<A NAME="lbAF">&nbsp;</A>
+<H2>DIAGNOSTICS</H2>
+
+Fatal errors in the address-supplying functions are:
+unknown address family.
+<A NAME="lbAG">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">DIAGNOSTICS</A><DD>
+<DT><A HREF="#lbAG">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_verify.8.html b/doc/manpage.d/ipsec_verify.8.html
new file mode 100644
index 000000000..09d04894b
--- /dev/null
+++ b/doc/manpage.d/ipsec_verify.8.html
@@ -0,0 +1,107 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_VERIFY</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_VERIFY</H1>
+Section: Maintenance Commands (8)<BR>Updated: 8 June 2002<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec verify - see if FreeSWAN has been installed correctly
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>ipsec</B>
+
+<B>verify</B>
+
+[
+<B>--host</B>
+
+&nbsp;name&nbsp;]
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<P>
+
+Invoked without argument,
+<I>verify  </I>
+
+examines the local system for a number of common system faults: 
+IPsec not in path, no secrets file generated, 
+pluto not running, and IPsec support not present in kernel
+(or IPsec module not loaded).
+If two or more interfaces are found, it performs checks relevant on an 
+IPsec gateway: whether IP forwarding is allowed, and if so, 
+whether MASQ or NAT rules are in play.
+<P>
+
+In addition, 
+<I>verify </I>
+
+performs checks relevant to Opportunistic Encryption. 
+It looks in forward DNS for a TXT record for the system's hostname, and
+in reverse DNS for a TXT record for the system's IP addresses.
+It checks whether the system has a public IP. 
+<P>
+
+The
+<B>--host</B>
+
+option causes
+<B>verify</B>
+
+to look for a TXT record for 
+<I>name</I>
+
+in forward and reverse DNS.
+<A NAME="lbAE">&nbsp;</A>
+<H2>FILES</H2>
+
+<PRE>
+/proc/net/ipsec_eroute
+/etc/ipsec.secrets
+</PRE>
+
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org">http://www.freeswan.org</A>&gt;
+by Michael Richardson.
+<A NAME="lbAG">&nbsp;</A>
+<H2>BUGS</H2>
+
+<I>Verify </I>
+
+does not check for 
+<B>ipchains</B>
+
+masquerading.
+<P>
+
+<I>Verify</I>
+
+does not look for TXT records for Opportunistic clients behind the system.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">FILES</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+<DT><A HREF="#lbAG">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_version.3.html b/doc/manpage.d/ipsec_version.3.html
new file mode 100644
index 000000000..bcad75a46
--- /dev/null
+++ b/doc/manpage.d/ipsec_version.3.html
@@ -0,0 +1,94 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_VERSION</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_VERSION</H1>
+Section: C Library Functions (3)<BR>Updated: 21 Nov 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec ipsec_version_code - get IPsec version code
+<BR>
+
+ipsec ipsec_version_string - get full IPsec version string
+<BR>
+
+ipsec ipsec_copyright_notice - get IPsec copyright notice
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *ipsec_version_code(void);</B>
+
+<BR>
+
+<B>const char *ipsec_version_string(void);</B>
+
+<BR>
+
+<B>const char **ipsec_copyright_notice(void);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions provide information on version numbering and copyright
+of the Linux FreeS/WAN IPsec implementation.
+<P>
+
+<I>Ipsec_version_code</I>
+
+returns a pointer to a string constant
+containing the current IPsec version code,
+such as ``1.92'' or ``snap2001Nov19b''.
+<P>
+
+<I>Ipsec_version_string</I>
+
+returns a pointer to a string constant giving a full version identification,
+consisting of the version code preceded by a prefix identifying the software,
+e.g. ``Linux FreeS/WAN 1.92''.
+<P>
+
+<I>Ipsec_copyright_notice</I>
+
+returns a pointer to a vector of pointers,
+terminated by a
+<B>NULL</B>,
+
+which is the text of a suitable copyright notice.
+Each pointer points to a string constant (possibly empty) which is one line
+of the somewhat-verbose copyright notice.
+The strings are NUL-terminated and do not contain a newline;
+supplying suitable line termination for the output device is
+the caller's responsibility.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8)
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_version.5.html b/doc/manpage.d/ipsec_version.5.html
new file mode 100644
index 000000000..89bee0f97
--- /dev/null
+++ b/doc/manpage.d/ipsec_version.5.html
@@ -0,0 +1,103 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_VERSION</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_VERSION</H1>
+Section: File Formats (5)<BR>Updated: 29 Jun 2000<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec_version - lists KLIPS version information
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>cat</B>
+
+<B>/proc/net/ipsec_version</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<I>/proc/net/ipsec_version</I>
+
+is a read-only file which lists the currently running KLIPS version
+information.
+<P>
+
+<A NAME="lbAE">&nbsp;</A>
+<H2>EXAMPLES</H2>
+
+<DL COMPACT>
+<DT><B>FreeS/WAN version: 1.4</B>
+
+<DD>
+</DL>
+<P>
+
+shows that the currently loaded
+<B>KLIPS</B>
+
+is from
+<B>FreeS/WAN 1.4.</B>
+
+<P>
+
+<A NAME="lbAF">&nbsp;</A>
+<H2>FILES</H2>
+
+/proc/net/ipsec_version
+<A NAME="lbAG">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_manual.8.html">ipsec_manual</A>(8), <A HREF="ipsec_eroute.5.html">ipsec_eroute</A>(5), <A HREF="ipsec_spi.5.html">ipsec_spi</A>(5),
+<A HREF="ipsec_spigrp.5.html">ipsec_spigrp</A>(5), <A HREF="ipsec_klipsdebug.5.html">ipsec_klipsdebug</A>(5), <A HREF="ipsec_tncfg.8.html">ipsec_tncfg</A>(8), <A HREF="ipsec_pf_key.5.html">ipsec_pf_key</A>(5)
+<A NAME="lbAH">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the Linux FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org/">http://www.freeswan.org/</A>&gt;
+by Richard Guy Briggs.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">EXAMPLES</A><DD>
+<DT><A HREF="#lbAF">FILES</A><DD>
+<DT><A HREF="#lbAG">SEE ALSO</A><DD>
+<DT><A HREF="#lbAH">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_version_code.3.html b/doc/manpage.d/ipsec_version_code.3.html
new file mode 100644
index 000000000..bcad75a46
--- /dev/null
+++ b/doc/manpage.d/ipsec_version_code.3.html
@@ -0,0 +1,94 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_VERSION</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_VERSION</H1>
+Section: C Library Functions (3)<BR>Updated: 21 Nov 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec ipsec_version_code - get IPsec version code
+<BR>
+
+ipsec ipsec_version_string - get full IPsec version string
+<BR>
+
+ipsec ipsec_copyright_notice - get IPsec copyright notice
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *ipsec_version_code(void);</B>
+
+<BR>
+
+<B>const char *ipsec_version_string(void);</B>
+
+<BR>
+
+<B>const char **ipsec_copyright_notice(void);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions provide information on version numbering and copyright
+of the Linux FreeS/WAN IPsec implementation.
+<P>
+
+<I>Ipsec_version_code</I>
+
+returns a pointer to a string constant
+containing the current IPsec version code,
+such as ``1.92'' or ``snap2001Nov19b''.
+<P>
+
+<I>Ipsec_version_string</I>
+
+returns a pointer to a string constant giving a full version identification,
+consisting of the version code preceded by a prefix identifying the software,
+e.g. ``Linux FreeS/WAN 1.92''.
+<P>
+
+<I>Ipsec_copyright_notice</I>
+
+returns a pointer to a vector of pointers,
+terminated by a
+<B>NULL</B>,
+
+which is the text of a suitable copyright notice.
+Each pointer points to a string constant (possibly empty) which is one line
+of the somewhat-verbose copyright notice.
+The strings are NUL-terminated and do not contain a newline;
+supplying suitable line termination for the output device is
+the caller's responsibility.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8)
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_version_string.3.html b/doc/manpage.d/ipsec_version_string.3.html
new file mode 100644
index 000000000..bcad75a46
--- /dev/null
+++ b/doc/manpage.d/ipsec_version_string.3.html
@@ -0,0 +1,94 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_VERSION</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_VERSION</H1>
+Section: C Library Functions (3)<BR>Updated: 21 Nov 2001<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec ipsec_version_code - get IPsec version code
+<BR>
+
+ipsec ipsec_version_string - get full IPsec version string
+<BR>
+
+ipsec ipsec_copyright_notice - get IPsec copyright notice
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>
+
+<P>
+<B>const char *ipsec_version_code(void);</B>
+
+<BR>
+
+<B>const char *ipsec_version_string(void);</B>
+
+<BR>
+
+<B>const char **ipsec_copyright_notice(void);</B>
+
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+These functions provide information on version numbering and copyright
+of the Linux FreeS/WAN IPsec implementation.
+<P>
+
+<I>Ipsec_version_code</I>
+
+returns a pointer to a string constant
+containing the current IPsec version code,
+such as ``1.92'' or ``snap2001Nov19b''.
+<P>
+
+<I>Ipsec_version_string</I>
+
+returns a pointer to a string constant giving a full version identification,
+consisting of the version code preceded by a prefix identifying the software,
+e.g. ``Linux FreeS/WAN 1.92''.
+<P>
+
+<I>Ipsec_copyright_notice</I>
+
+returns a pointer to a vector of pointers,
+terminated by a
+<B>NULL</B>,
+
+which is the text of a suitable copyright notice.
+Each pointer points to a string constant (possibly empty) which is one line
+of the somewhat-verbose copyright notice.
+The strings are NUL-terminated and do not contain a newline;
+supplying suitable line termination for the output device is
+the caller's responsibility.
+<A NAME="lbAE">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<A HREF="ipsec.8.html">ipsec</A>(8)
+<A NAME="lbAF">&nbsp;</A>
+<H2>HISTORY</H2>
+
+Written for the FreeS/WAN project by Henry Spencer.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DT><A HREF="#lbAE">SEE ALSO</A><DD>
+<DT><A HREF="#lbAF">HISTORY</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpage.d/ipsec_whack.8.html b/doc/manpage.d/ipsec_whack.8.html
new file mode 100644
index 000000000..2e2ce4c2f
--- /dev/null
+++ b/doc/manpage.d/ipsec_whack.8.html
@@ -0,0 +1,1824 @@
+Content-type: text/html
+
+<HTML><HEAD><TITLE>Manpage of IPSEC_PLUTO</TITLE>
+</HEAD><BODY>
+<H1>IPSEC_PLUTO</H1>
+Section: Maintenance Commands (8)<BR>Updated: 28 March 1999<BR><A HREF="#index">Index</A>
+<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
+
+<A NAME="lbAB">&nbsp;</A>
+<H2>NAME</H2>
+
+ipsec pluto - IPsec IKE keying daemon
+<BR>
+
+ipsec whack - control interface for IPSEC keying daemon
+<A NAME="lbAC">&nbsp;</A>
+<H2>SYNOPSIS</H2>
+
+
+
+<DL COMPACT>
+<DT>
+<B>
+<DD>ipsec pluto
+[--help]
+[--version]
+[--optionsfrom&nbsp;</B><I>filename</I>]
+[--nofork]
+[--stderrlog]
+[--noklips]
+[--uniqueids]
+[<B>--interface</B> <I>interfacename</I>]
+[--ikeport&nbsp;<I>portnumber</I>]
+[--ctlbase&nbsp;<I>path</I>]
+[--secretsfile&nbsp;<I>secrets-file</I>]
+[--adns <I>pathname</I>]
+[--lwdnsq <I>pathname</I>]
+[--perpeerlog]
+[--perpeerlogbase&nbsp;<I>dirname</I>]
+[--debug-none]
+[--debug-all]
+[--debug-raw]
+[--debug-crypt]
+[--debug-parsing]
+[--debug-emitting]
+[--debug-control]
+[--debug-lifecycle]
+[--debug-klips]
+[--debug-dns]
+[--debug-oppo]
+[--debug-private]
+<DT>
+<B>
+<DD>ipsec whack
+[--help]
+[--version]
+<DT>
+
+<DD>ipsec whack
+--name&nbsp;</B><I>connection-name</I>
+<BR>
+
+[--id&nbsp;<I>id</I>] [--host&nbsp;<I>ip-address</I>]
+[--ikeport&nbsp;<I>port-number</I>]
+[--nexthop&nbsp;<I>ip-address</I>]
+[--client&nbsp;<I>subnet</I>]
+[--dnskeyondemand]
+[--updown&nbsp;<I>updown</I>]
+<BR>
+
+--to
+<BR>
+
+[--id&nbsp;<I>id</I>]
+[--host&nbsp;<I>ip-address</I>]
+[--ikeport&nbsp;<I>port-number</I>]
+[--nexthop&nbsp;<I>ip-address</I>]
+[--client&nbsp;<I>subnet</I>]
+[--dnskeyondemand]
+[--updown&nbsp;<I>updown</I>]
+<BR>
+
+[--psk]
+[--rsasig]
+[--encrypt]
+[--authenticate]
+[--compress]
+[--tunnel]
+[--pfs]
+[--disablearrivalcheck]
+[--ipv4]
+[--ipv6]
+[--tunnelipv4]
+[--tunnelipv6]
+[--ikelifetime&nbsp;<I>seconds</I>]
+[--ipseclifetime&nbsp;<I>seconds</I>]
+[--rekeymargin&nbsp;<I>seconds</I>]
+[--rekeyfuzz&nbsp;<I>percentage</I>]
+[--keyingtries&nbsp;<I>count</I>]
+[--dontrekey]
+[--delete]
+[--ctlbase&nbsp;<I>path</I>]
+[--optionsfrom&nbsp;<I>filename</I>]
+[--label&nbsp;<I>string</I>]
+<DT>
+<B>
+<DD>ipsec whack
+--keyid&nbsp;</B><I>id</I>
+[--addkey]
+[--pubkeyrsa&nbsp;<I>key</I>]
+[--ctlbase&nbsp;<I>path</I>]
+[--optionsfrom&nbsp;<I>filename</I>]
+[--label&nbsp;<I>string</I>]
+<DT>
+<B>
+<DD>ipsec whack
+--myid&nbsp;</B><I>id</I>
+<DT>
+<B>
+<DD>ipsec whack
+--listen|--unlisten
+[--ctlbase&nbsp;</B><I>path</I>]
+[--optionsfrom&nbsp;<I>filename</I>]
+[--label&nbsp;<I>string</I>]
+<DT>
+<B>
+<DD>ipsec whack
+--route|--unroute
+--name&nbsp;</B><I>connection-name</I>
+[--ctlbase&nbsp;<I>path</I>]
+[--optionsfrom&nbsp;<I>filename</I>]
+[--label&nbsp;<I>string</I>]
+<DT>
+<B>
+<DD>ipsec whack
+--initiate|--terminate
+--name&nbsp;</B><I>connection-name</I>
+[--asynchronous]
+[--ctlbase&nbsp;<I>path</I>]
+[--optionsfrom&nbsp;<I>filename</I>]
+[--label&nbsp;<I>string</I>]
+<DT>
+<B>
+<DD>ipsec whack
+[--tunnelipv4]
+[--tunnelipv6]
+--oppohere </B><I>ip-address</I>
+--oppothere <I>ip-address</I>
+<DT>
+<B>
+<DD>ipsec whack
+--delete
+--name&nbsp;</B><I>connection-name</I>
+[--ctlbase&nbsp;<I>path</I>]
+[--optionsfrom&nbsp;<I>filename</I>]
+[--label&nbsp;<I>string</I>]
+<DT>
+<B>
+<DD>ipsec whack
+--deletestate&nbsp;</B><I>state-number</I>
+[--ctlbase&nbsp;<I>path</I>]
+[--optionsfrom&nbsp;<I>filename</I>]
+[--label&nbsp;<I>string</I>]
+<DT>
+<B>
+<DD>ipsec whack
+[--name&nbsp;</B><I>connection-name</I>]
+[--debug-none]
+[--debug-all]
+[--debug-raw]
+[--debug-crypt]
+[--debug-parsing]
+[--debug-emitting]
+[--debug-control]
+[--debug-lifecycle]
+[--debug-klips]
+[--debug-dns]
+[--debug-oppo]
+[--debug-private]
+[--ctlbase&nbsp;<I>path</I>]
+[--optionsfrom&nbsp;<I>filename</I>]
+[--label&nbsp;<I>string</I>]
+<DT>
+<B>
+<DD>ipsec whack
+--status
+[--ctlbase&nbsp;</B><I>path</I>]
+[--optionsfrom&nbsp;<I>filename</I>]
+[--label&nbsp;<I>string</I>]
+<DT>
+<B>
+<DD>ipsec whack
+--shutdown
+[--ctlbase&nbsp;</B><I>path</I>]
+[--optionsfrom&nbsp;<I>filename</I>]
+[--label&nbsp;<I>string</I>]
+
+
+
+</DL>
+<A NAME="lbAD">&nbsp;</A>
+<H2>DESCRIPTION</H2>
+
+<B>pluto</B>
+
+is an IKE (``IPsec Key Exchange'') daemon.
+<B>whack</B>
+
+is an auxiliary program to allow requests to be made to a running
+<B>pluto</B>.
+
+<P>
+
+<B>pluto</B>
+
+is used to automatically build shared ``security associations'' on a
+system that has IPsec, the secure IP protocol.
+In other words,
+<B>pluto</B>
+
+can eliminate much of the work of manual keying.
+The actual
+secure transmission of packets is the responsibility of other parts of
+the system (see
+<B>KLIPS</B>,
+
+the companion implementation of IPsec).
+<I><A HREF="ipsec_auto.8.html">ipsec_auto</A></I>(8) provides a more convenient interface to
+<B>pluto</B> and <B>whack</B>.
+<A NAME="lbAE">&nbsp;</A>
+<H3>IKE's Job</H3>
+
+<P>
+
+A <I>Security Association</I> (<I>SA</I>) is an agreement between two network nodes on
+how to process certain traffic between them.  This processing involves
+encapsulation, authentication, encryption, or compression.
+<P>
+
+IKE can be deployed on a network node to negotiate Security
+Associations for that node.  These IKE implementations can only
+negotiate with other IKE implementations, so IKE must be on each node
+that is to be an endpoint of an IKE-negotiated Security Association.
+No other nodes need to be running IKE.
+<P>
+
+An IKE instance (i.e. an IKE implementation on a particular network
+node) communicates with another IKE instance using UDP IP packets, so
+there must be a route between the nodes in each direction.
+<P>
+
+The negotiation of Security Associations requires a number of choices
+that involve tradeoffs between security, convenience, trust, and
+efficiency.  These are policy issues and are normally specified to the
+IKE instance by the system administrator.
+<P>
+
+IKE deals with two kinds of Security Associations.  The first part of
+a negotiation between IKE instances is to build an ISAKMP SA.  An
+ISAKMP SA is used to protect communication between the two IKEs.
+IPsec SAs can then be built by the IKEs - these are used to carry
+protected IP traffic between the systems.
+<P>
+
+The negotiation of the ISAKMP SA is known as Phase 1.  In theory,
+Phase 1 can be accomplished by a couple of different exchange types,
+but we only implement one called Main Mode (we don't implement
+Aggressive Mode).
+<P>
+
+Any negotiation under the protection of an ISAKMP SA, including the
+negotiation of IPsec SAs, is part of Phase 2.  The exchange type
+that we use to negotiate an IPsec SA is called Quick Mode.
+<P>
+
+IKE instances must be able to authenticate each other as part of their
+negotiation of an ISAKMP SA.  This can be done by several mechanisms
+described in the draft standards.
+<P>
+
+IKE negotiation can be initiated by any instance with any other.  If
+both can find an agreeable set of characteristics for a Security
+Association, and both recognize each others authenticity, they can set
+up a Security Association.  The standards do not specify what causes
+an IKE instance to initiate a negotiation.
+<P>
+
+In summary, an IKE instance is prepared to automate the management of
+Security Associations in an IPsec environment, but a number of issues
+are considered policy and are left in the system administrator's hands.
+<A NAME="lbAF">&nbsp;</A>
+<H3>Pluto</H3>
+
+<P>
+
+<B>pluto</B> is an implementation of IKE.  It runs as a daemon on a network
+node.  Currently, this network node must be a LINUX system running the
+<B>KLIPS</B> implementation of IPsec.
+<P>
+
+<B>pluto</B> only implements a subset of IKE.  This is enough for it to
+interoperate with other instances of <B>pluto</B>, and many other IKE
+implementations.  We are working on implementing more of IKE.
+<P>
+
+The policy for acceptable characteristics for Security Associations is
+mostly hardwired into the code of <B>pluto</B> (spdb.c).  Eventually
+this will be moved into a security policy database with reasonable
+expressive power and more convenience.
+<P>
+
+<B>pluto</B> uses shared secrets or RSA signatures to authenticate
+peers with whom it is negotiating.
+<P>
+
+<B>pluto</B> initiates negotiation of a Security Association when it is
+manually prodded: the program <B>whack</B> is run to trigger this.
+It will also initiate a negotiation when <B>KLIPS</B> traps an outbound packet
+for Opportunistic Encryption.
+<P>
+
+<B>pluto</B> implements ISAKMP SAs itself.  After it has negotiated the
+characteristics of an IPsec SA, it directs <B>KLIPS</B> to implement it.
+It also invokes a script to adjust any firewall and issue <I><A HREF="route.8.html">route</A></I>(8)
+commands to direct IP packets through <B>KLIPS</B>.
+<P>
+
+When <B>pluto</B> shuts down, it closes all Security Associations.
+<A NAME="lbAG">&nbsp;</A>
+<H3>Before Running Pluto</H3>
+
+<P>
+
+<B>pluto</B> runs as a daemon with userid root.  Before running it, a few
+things must be set up.
+<P>
+
+<B>pluto</B> requires <B>KLIPS</B>, the FreeS/WAN implementation of IPsec.
+All of the components of <B>KLIPS</B> and <B>pluto</B> should be installed.
+<P>
+
+<B>pluto</B> supports multiple public networks (that is, networks
+that are considered insecure and thus need to have their traffic
+encrypted or authenticated).  It discovers the
+public interfaces to use by looking at all interfaces that are
+configured (the <B>--interface</B> option can be used to limit
+the interfaces considered).
+It does this only when <B>whack</B> tells it to --listen,
+so the interfaces must be configured by then.  Each interface with a name of the form
+<B>ipsec</B>[<B>0</B>-<B>9</B>] is taken as a <B>KLIPS</B> virtual public interface.
+Another network interface with the same IP address (there should be only
+one) is taken as the corresponding real public
+interface.  <I><A HREF="ifconfig.8.html">ifconfig</A></I>(8) with the <B>-a</B> flag will show
+the name and status of each network interface.
+<P>
+
+<B>pluto</B> requires a database of preshared secrets and RSA private keys.
+This is described in the
+<I><A HREF="ipsec.secrets.5.html">ipsec.secrets</A></I>(5).
+
+<B>pluto</B> is told of RSA public keys via <B>whack</B> commands.
+If the connection is Opportunistic, and no RSA public key is known,
+<B>pluto</B> will attempt to fetch RSA keys using the Domain Name System.
+<A NAME="lbAH">&nbsp;</A>
+<H3>Setting up <B>KLIPS</B> for <B>pluto</B></H3>
+
+<P>
+
+The most basic network topology that <B>pluto</B> supports has two security
+gateways negotiating on behalf of client subnets.  The diagram of RGB's
+testbed is a good example (see <I>klips/doc/rgb_setup.txt</I>).
+<P>
+
+The file <I>INSTALL</I> in the base directory of this distribution
+explains how to start setting up the whole system, including <B>KLIPS</B>.
+<P>
+
+Make sure that the security gateways have routes to each other.  This
+is usually covered by the default route, but may require issuing
+<I><A HREF="route.8.html">route</A></I>(8)
+
+commands.  The route must go through a particular IP
+interface (we will assume it is <I>eth0</I>, but it need not be).  The
+interface that connects the security gateway to its client must be a
+different one.
+<P>
+
+It is necessary to issue a
+<I><A HREF="ipsec_tncfg.8.html">ipsec_tncfg</A></I>(8)
+
+command on each gateway.  The required command is:
+<P>
+&nbsp;&nbsp;&nbsp;ipsec tncfg --attach&nbsp;--virtual&nbsp;ipsec0 --physical&nbsp;eth0
+<P>
+A command to set up the ipsec0 virtual interface will also need to be
+run.  It will have the same parameters as the command used to set up
+the physical interface to which it has just been connected using
+<I><A HREF="ipsec_tncfg.8.html">ipsec_tncfg</A></I>(8).
+
+<A NAME="lbAI">&nbsp;</A>
+<H3>ipsec.secrets file</H3>
+
+<P>
+
+A <B>pluto</B> daemon and another IKE daemon (for example, another instance
+of <B>pluto</B>) must convince each other that they are who they are supposed
+to be before any negotiation can succeed.  This authentication is
+accomplished by using either secrets that have been shared beforehand
+(manually) or by using RSA signatures.  There are other techniques,
+but they have not been implemented in <B>pluto</B>.
+<P>
+
+The file <I>/etc/ipsec.secrets</I> is used to keep preshared secret keys
+and RSA private keys for
+authentication with other IKE daemons.  For debugging, there is an
+argument to the <B>pluto</B> command to use a different file.
+This file is described in
+<I><A HREF="ipsec.secrets.5.html">ipsec.secrets</A></I>(5).
+
+<A NAME="lbAJ">&nbsp;</A>
+<H3>Running Pluto</H3>
+
+<P>
+
+To fire up the daemon, just type <B>pluto</B> (be sure to be running as
+the superuser).
+The default IKE port number is 500, the UDP port assigned by IANA for IKE Daemons.
+<B>pluto</B> must be run by the superuser to be able to use the UDP 500 port.
+<P>
+
+<B>pluto</B> attempts to create a lockfile with the name
+<I>/var/run/pluto.pid</I>.  If the lockfile cannot be created,
+<B>pluto</B> exits - this prevents multiple <B>pluto</B>s from
+competing  Any ``leftover'' lockfile must be removed before
+<B>pluto</B> will run.  <B>pluto</B> writes its pid into this file so
+that scripts can find it.  This lock will not function properly if it
+is on an NFS volume (but sharing locks on multiple machines doesn't
+make sense anyway).
+<P>
+
+<B>pluto</B> then forks and the parent exits.  This is the conventional
+``daemon fork''.  It can make debugging awkward, so there is an option
+to suppress this fork.
+<P>
+
+All logging, including diagnostics, is sent to
+<I><A HREF="syslog.3.html">syslog</A></I>(3)
+
+with facility=authpriv;
+it decides where to put these messages (possibly in /var/log/secure).
+Since this too can make debugging awkward, there is an option to
+steer logging to stderr.
+<P>
+
+If the <B>--perpeerlog</B> option is given, then pluto will open
+a log file per connection. By default, this is in /var/log/pluto/peer,
+in a subdirectory formed by turning all dot (.) [IPv4} or colon (:)
+[IPv6] into slashes (/).
+<P>
+
+The base directory can be changed with the <B>--perpeerlogbase</B>.
+<P>
+
+Once <B>pluto</B> is started, it waits for requests from <B>whack</B>.
+<A NAME="lbAK">&nbsp;</A>
+<H3>Pluto's Internal State</H3>
+
+<P>
+
+To understand how to use <B>pluto</B>, it is helpful to understand a little
+about its internal state.  Furthermore, the terminology is needed to decipher
+some of the diagnostic messages.
+<P>
+
+The <I>(potential) connection</I> database describes attributes of a
+connection.  These include the IP addresses of the hosts and client
+subnets and the security characteristics desired.  <B>pluto</B>
+requires this information (simply called a connection) before it can
+respond to a request to build an SA.  Each connection is given a name
+when it is created, and all references are made using this name.
+<P>
+
+During the IKE exchange to build an SA, the information about the
+negotiation is represented in a <I>state object</I>.  Each state object
+reflects how far the negotiation has reached.  Once the negotiation is
+complete and the SA established, the state object remains to represent
+the SA.  When the SA is terminated, the state object is discarded.
+Each State object is given a serial number and this is used to refer
+to the state objects in logged messages.
+<P>
+
+Each state object corresponds to a connection and can be thought of
+as an instantiation of that connection.
+At any particular time, there may be any number of state objects
+corresponding to a particular connection.
+Often there is one representing an ISAKMP SA and another representing
+an IPsec SA.
+<P>
+
+<B>KLIPS</B> hooks into the routing code in a LINUX kernel.
+Traffic to be processed by an IPsec SA must be directed through
+<B>KLIPS</B> by routing commands.  Furthermore, the processing to be
+done is specified by <I>ipsec <A HREF="eroute.8.html">eroute</A>(8)</I> commands.
+<B>pluto</B> takes the responsibility of managing both of these special
+kinds of routes.
+<P>
+
+Each connection may be routed, and must be while it has an IPsec SA.
+The connection specifies the characteristics of the route: the
+interface on this machine, the ``gateway'' (the nexthop),
+and the peer's client subnet.  Two
+connections may not be simultaneously routed if they are for the same
+peer's client subnet but use different interfaces or gateways
+(<B>pluto</B>'s logic does not reflect any advanced routing capabilities).
+<P>
+
+Each eroute is associated with the state object for an IPsec SA
+because it has the particular characteristics of the SA.
+Two eroutes conflict if they specify the identical local
+and remote clients (unlike for routes, the local clients are
+taken into account).
+<P>
+
+When <B>pluto</B> needs to install a route for a connection,
+it must make sure that no conflicting route is in use.  If another
+connection has a conflicting route, that route will be taken down, as long
+as there is no IPsec SA instantiating that connection.
+If there is such an IPsec SA, the attempt to install a route will fail.
+<P>
+
+There is an exception.  If <B>pluto</B>, as Responder, needs to install
+a route to a fixed client subnet for a connection, and there is
+already a conflicting route, then the SAs using the route are deleted
+to make room for the new SAs.  The rationale is that the new
+connection is probably more current.  The need for this usually is a
+product of Road Warrior connections (these are explained later; they
+cannot be used to initiate).
+<P>
+
+When <B>pluto</B> needs to install an eroute for an IPsec SA (for a
+state object), first the state object's connection must be routed (if
+this cannot be done, the eroute and SA will not be installed).
+If a conflicting eroute is already in place for another connection,
+the eroute and SA will not be installed (but note that the routing
+exception mentioned above may have already deleted potentially conflicting SAs).
+If another IPsec
+SA for the same connection already has an eroute, all its outgoing traffic
+is taken over by the new eroute.  The incoming traffic will still be
+processed.  This characteristic is exploited during rekeying.
+<P>
+
+All of these routing characteristics are expected change when
+<B>KLIPS</B> is modified to use the firewall hooks in the LINUX 2.4.x
+kernel.
+<A NAME="lbAL">&nbsp;</A>
+<H3>Using Whack</H3>
+
+<P>
+
+<B>whack</B> is used to command a running <B>pluto</B>.
+<B>whack</B> uses a UNIX domain socket to speak to <B>pluto</B>
+(by default, <I>/var/pluto.ctl</I>).
+<P>
+
+<B>whack</B> has an intricate argument syntax.
+This syntax allows many different functions to be specified.
+The help form shows the usage or version information.
+The connection form gives <B>pluto</B> a description of a potential connection.
+The public key form informs <B>pluto</B> of the RSA public key for a potential peer.
+The delete form deletes a connection description and all SAs corresponding
+to it.
+The listen form tells <B>pluto</B> to start or stop listening on the public interfaces
+for IKE requests from peers.
+The route form tells <B>pluto</B> to set up routing for a connection;
+the unroute form undoes this.
+The initiate form tells <B>pluto</B> to negotiate an SA corresponding to a connection.
+The terminate form tells <B>pluto</B> to remove all SAs corresponding to a connection,
+including those being negotiated.
+The status form displays the <B>pluto</B>'s internal state.
+The debug form tells <B>pluto</B> to change the selection of debugging output
+``on the fly''.  The shutdown form tells
+<B>pluto</B> to shut down, deleting all SAs.
+<P>
+
+Most options are specific to one of the forms, and will be described
+with that form.  There are three options that apply to all forms.
+<DL COMPACT>
+<DT><B>--ctlbase</B>&nbsp;<I>path</I><DD>
+<I>path</I>.ctl is used as the UNIX domain socket for talking
+to <B>pluto</B>.
+This option facilitates debugging.
+<DT><B>--optionsfrom</B>&nbsp;<I>filename</I><DD>
+adds the contents of the file to the argument list.
+<DT><B>--label</B>&nbsp;<I>string</I><DD>
+adds the string to all error messages generated by <B>whack</B>.
+</DL>
+<P>
+
+The help form of <B>whack</B> is self-explanatory.
+<DL COMPACT>
+<DT><B>--help</B><DD>
+display the usage message.
+<DT><B>--version</B><DD>
+display the version of <B>whack</B>.
+</DL>
+<P>
+
+The connection form describes a potential connection to <B>pluto</B>.
+<B>pluto</B> needs to know what connections can and should be negotiated.
+When <B>pluto</B> is the initiator, it needs to know what to propose.
+When <B>pluto</B> is the responder, it needs to know enough to decide whether
+is is willing to set up the proposed connection.
+<P>
+
+The description of a potential connection can specify a large number
+of details.  Each connection has a unique name.  This name will appear
+in a updown shell command, so it should not contain punctuation
+that would make the command ill-formed.
+<DL COMPACT>
+<DT><B>--name</B>&nbsp;<I>connection-name</I><DD>
+</DL>
+<P>
+
+The topology of
+a connection is symmetric, so to save space here is half a picture:
+<P>
+&nbsp;&nbsp;&nbsp;client_subnet&lt;--&gt;host:ikeport&lt;--&gt;nexthop&lt;---
+<P>
+A similar trick is used in the flags.  The same flag names are used for
+both ends.  Those before the <B>--to</B> flag describe the left side
+and those afterwards describe the right side.  When <B>pluto</B> attempts
+to use the connection, it decides whether it is the left side or the right
+side of the connection, based on the IP numbers of its interfaces.
+<DL COMPACT>
+<DT><B>--id</B>&nbsp;<I>id</I><DD>
+the identity of the end.  Currently, this can be an IP address (specified
+as dotted quad or as a Fully Qualified Domain Name, which will be resolved
+immediately) or as a Fully Qualified Domain Name itself (prefixed by ``@''
+to signify that it should not be resolved), or as <A HREF="mailto:user@FQDN">user@FQDN</A>, or as the
+magic value <B>%myid</B>.
+<B>Pluto</B> only authenticates the identity, and does not use it for
+addressing, so, for example, an IP address need not be the one to which
+packets are to be sent.  If the option is absent, the
+identity defaults to the IP address specified by <B>--host</B>.
+<B>%myid</B> allows the identity to be separately specified (by the <B>pluto</B> or <B>whack</B> option <B>--myid</B>
+or by the <B><A HREF="ipsec.conf.5.html">ipsec.conf</A></B>(5) <B>config setup</B> parameter myid).
+Otherwise, <B>pluto</B> tries to guess what <B>%myid</B> should stand for:
+the IP address of <B>%defaultroute</B>, if it is supported by a suitable TXT record in the reverse domain for that IP address,
+or the system's hostname, if it is supported by a suitable TXT record in its forward domain.
+
+<DT><B>--host</B>&nbsp;<I>ip-address</I><DD>
+<DT><B>--host</B>&nbsp;<B>%any</B><DD>
+<DT><B>--host</B>&nbsp;<B>%opportunistic</B><DD>
+the IP address of the end (generally the public interface).
+If <B>pluto</B> is to act as a responder
+for IKE negotiations initiated from unknown IP addresses (the
+``Road Warrior'' case), the
+IP address should be specified as <B>%any</B> (currently,
+the obsolete notation <B>0.0.0.0</B> is also accepted for this).
+If <B>pluto</B> is to opportunistically initiate the connection,
+use <B>%opportunistic</B>
+<DT><B>--ikeport</B>&nbsp;<I>port-number</I><DD>
+the UDP port that IKE listens to on that host.  The default is 500.
+(<B>pluto</B> on this machine uses the port specified by its own command
+line argument, so this only affects where <B>pluto</B> sends messages.)
+<DT><B>--nexthop</B>&nbsp;<I>ip-address</I><DD>
+where to route packets for the peer's client (presumably for the peer too,
+but it will not be used for this).
+When <B>pluto</B> installs an IPsec SA, it issues a route command.
+It uses the nexthop as the gateway.
+The default is the peer's IP address (this can be explicitly written as
+<B>%direct</B>; the obsolete notation <B>0.0.0.0</B> is accepted).
+This option is necessary if <B>pluto</B>'s host's interface used for sending
+packets to the peer is neither point-to-point nor directly connected to the
+peer.
+<DT><B>--client</B>&nbsp;<I>subnet</I><DD>
+the subnet for which the IPsec traffic will be destined.  If not specified,
+the host will be the client.
+The subnet can be specified in any of the forms supported by <I><A HREF="ipsec_atosubnet.3.html">ipsec_atosubnet</A></I>(3).
+The general form is <I>address</I>/<I>mask</I>.  The <I>address</I> can be either
+a domain name or four decimal numbers (specifying octets) separated by dots.
+The most convenient form of the <I>mask</I> is a decimal integer, specifying
+the number of leading one bits in the mask.  So, for example, 10.0.0.0/8
+would specify the class A network ``Net 10''.
+<DT><B>--dnskeyondemand]</B><DD>
+specifies that when an RSA public key is needed to authenticate this
+host, and it isn't already known, fetch it from DNS.
+<DT><B>--updown</B>&nbsp;<I>updown</I><DD>
+specifies an external shell command to be run whenever <B>pluto</B>
+brings up or down a connection.
+The script is used to build a shell command, so it may contain positional
+parameters, but ought not to have punctuation that would cause the
+resulting command to be ill-formed.
+The default is <I>ipsec _updown</I>.
+<DT><B>--to</B><DD>
+separates the specification of the left and right ends of the connection.
+</DL>
+<P>
+
+The potential connection description also specifies characteristics of
+rekeying and security.
+<DL COMPACT>
+<DT><B>--psk</B><DD>
+Propose and allow preshared secret authentication for IKE peers.  This authentication
+requires that each side use the same secret.  May be combined with <B>--rsasig</B>;
+at least one must be specified.
+<DT><B>--rsasig</B><DD>
+Propose and allow RSA signatures for authentication of IKE peers.  This authentication
+requires that each side have have a private key of its own and know the
+public key of its peer.  May be combined with <B>--psk</B>;
+at least one must be specified.
+<DT><B>--encrypt</B><DD>
+All proposed or accepted IPsec SAs will include non-null ESP.
+The actual choices of transforms are wired into <B>pluto</B>.
+<DT><B>--authenticate</B><DD>
+All proposed IPsec SAs will include AH.
+All accepted IPsec SAs will include AH or ESP with authentication.
+The actual choices of transforms are wired into <B>pluto</B>.
+Note that this has nothing to do with IKE authentication.
+<DT><B>--compress</B><DD>
+All proposed IPsec SAs will include IPCOMP (compression).
+This will be ignored if KLIPS is not configured with IPCOMP support.
+<DT><B>--tunnel</B><DD>
+the IPsec SA should use tunneling.  Implicit if the SA is for clients.
+Must only be used with <B>--authenticate</B> or <B>--encrypt</B>.
+<DT><B>--ipv4</B><DD>
+The host addresses will be interpreted as IPv4 addresses.  This is the
+default.  Note that for a connection, all host addresses must be of
+the same Address Family (IPv4 and IPv6 use different Address Families).
+<DT><B>--ipv6</B><DD>
+The host addresses (including nexthop) will be interpreted as IPv6 addresses.
+Note that for a connection, all host addresses must be of
+the same Address Family (IPv4 and IPv6 use different Address Families).
+<DT><B>--tunnelipv4</B><DD>
+The client addresses will be interpreted as IPv4 addresses.  The default is
+to match what the host will be.  This does not imply <B>--tunnel</B> so the
+flag can be safely used when no tunnel is actually specified.
+Note that for a connection, all tunnel addresses must be of the same
+Address Family.
+<DT><B>--tunnelipv6</B><DD>
+The client addresses will be interpreted as IPv6 addresses.  The default is
+to match what the host will be.  This does not imply <B>--tunnel</B> so the
+flag can be safely used when no tunnel is actually specified.
+Note that for a connection, all tunnel addresses must be of the same
+Address Family.
+<DT><B>--pfs</B><DD>
+There should be Perfect Forward Secrecy - new keying material will
+be generated for each IPsec SA rather than being derived from the ISAKMP
+SA keying material.
+Since the group to be used cannot be negotiated (a dubious feature of the
+standard), <B>pluto</B> will propose the same group that was used during Phase 1.
+We don't implement a stronger form of PFS which would require that the
+ISAKMP SA be deleted after the IPSEC SA is negotiated.
+<DT><B>--disablearrivalcheck</B><DD>
+If the connection is a tunnel, allow packets arriving through the tunnel
+to have any source and destination addresses.
+</DL>
+<P>
+
+If none of the <B>--encrypt</B>, <B>--authenticate</B>, <B>--compress</B>,
+or <B>--pfs</B> flags is given, the initiating the connection will
+only build an ISAKMP SA.  For such a connection, client subnets have
+no meaning and must not be specified.
+<P>
+
+More work is needed to allow for flexible policies.  Currently
+policy is hardwired in the source file spdb.c.  The ISAKMP SAs may use
+Oakley groups MODP1024 and MODP1536; 3DES encryption; SHA1-96
+and MD5-96 authentication.  The IPsec SAs may use 3DES and
+MD5-96 or SHA1-96 for ESP, or just MD5-96 or SHA1-96 for AH.
+IPCOMP Compression is always Deflate.
+<DL COMPACT>
+<DT><B>--ikelifetime</B>&nbsp;<I>seconds</I><DD>
+how long <B>pluto</B> will propose that an ISAKMP SA be allowed to live.
+The default is 3600 (one hour) and the maximum is 28800 (8 hours).
+This option will not affect what is accepted.
+<B>pluto</B> will reject proposals that exceed the maximum.
+<DT><B>--ipseclifetime</B>&nbsp;<I>seconds</I><DD>
+how long <B>pluto</B> will propose that an IPsec SA be allowed to live.
+The default is 28800 (eight hours) and the maximum is 86400 (one day).
+This option will not affect what is accepted.
+<B>pluto</B> will reject proposals that exceed the maximum.
+<DT><B>--rekeymargin</B>&nbsp;<I>seconds</I><DD>
+how long before an SA's expiration should <B>pluto</B> try to negotiate
+a replacement SA.  This will only happen if <B>pluto</B> was the initiator.
+The default is 540 (nine minutes).
+<DT><B>--rekeyfuzz</B>&nbsp;<I>percentage</I><DD>
+maximum size of random component to add to rekeymargin, expressed as
+a percentage of rekeymargin.  <B>pluto</B> will select a delay uniformly
+distributed within this range.  By default, the percentage will be 100.
+If greater determinism is desired, specify 0.  It may be appropriate
+for the percentage to be much larger than 100.
+<DT><B>--keyingtries</B>&nbsp;<I>count</I><DD>
+how many times <B>pluto</B> should try to negotiate an SA,
+either for the first time or for rekeying.
+A value of 0 is interpreted as a very large number: never give up.
+The default is three.
+<DT><B>--dontrekey</B><DD>
+A misnomer.
+Only rekey a connection if we were the Initiator and there was recent
+traffic on the existing connection.
+This applies to Phase 1 and Phase 2.
+This is currently the only automatic way for a connection to terminate.
+It may be useful with Road Warrior or Opportunistic connections.
+<BR>
+
+Since SA lifetime negotiation is take-it-or-leave it, a Responder
+normally uses the shorter of the negotiated or the configured lifetime.
+This only works because if the lifetime is shorter than negotiated,
+the Responder will rekey in time so that everything works.
+This interacts badly with <B>--dontrekey</B>.  In this case,
+the Responder will end up rekeying to rectify a shortfall in an IPsec SA
+lifetime; for an ISAKMP SA, the Responder will accept the negotiated
+lifetime.
+<DT><B>--delete</B><DD>
+when used in the connection form, it causes any previous connection
+with this name to be deleted before this one is added.  Unlike a
+normal delete, no diagnostic is produced if there was no previous
+connection to delete.  Any routing in place for the connection is undone.
+</DL>
+<P>
+
+The delete form deletes a named connection description and any
+SAs established or negotiations initiated using this connection.
+Any routing in place for the connection is undone.
+<DL COMPACT>
+<DT><B>--delete</B><DD>
+<DT><B>--name</B>&nbsp;<I>connection-name</I><DD>
+</DL>
+<P>
+
+The deletestate form deletes the state object with the specified serial number.
+This is useful for selectively deleting instances of connections.
+<DL COMPACT>
+<DT><B>--deletestate</B>&nbsp;<I>state-number</I><DD>
+</DL>
+<P>
+
+The route form of the <B>whack</B> command tells <B>pluto</B> to set up
+routing for a connection.
+Although like a traditional route, it uses an ipsec device as a
+virtual interface.
+Once routing is set up, no packets will be
+sent ``in the clear'' to the peer's client specified in the connection.
+A TRAP shunt eroute will be installed; if outbound traffic is caught,
+Pluto will initiate the connection.
+An explicit <B>whack</B> route is not always needed: if it hasn't been
+done when an IPsec SA is being installed, one will be automatically attempted.
+<P>
+
+When a routing is attempted for a connection, there must not already
+be a routing for a different connection with the same subnet but different
+interface or destination, or if
+there is, it must not be being used by an IPsec SA.  Otherwise the
+attempt will fail.
+<DL COMPACT>
+<DT><B>--route</B><DD>
+<DT><B>--name</B>&nbsp;<I>connection-name</I><DD>
+</DL>
+<P>
+
+The unroute form of the <B>whack</B> command tells <B>pluto</B> to undo
+a routing.  <B>pluto</B> will refuse if an IPsec SA is using the connection.
+If another connection is sharing the same routing, it will be left in place.
+Without a routing, packets will be sent without encryption or authentication.
+<DL COMPACT>
+<DT><B>--unroute</B><DD>
+<DT><B>--name</B>&nbsp;<I>connection-name</I><DD>
+</DL>
+<P>
+
+The initiate form tells <B>pluto</B> to initiate a negotiation with another
+<B>pluto</B> (or other IKE daemon) according to the named connection.
+Initiation requires a route that <B>--route</B> would provide;
+if none is in place at the time an IPsec SA is being installed,
+<B>pluto</B> attempts to set one up.
+<DL COMPACT>
+<DT><B>--initiate</B><DD>
+<DT><B>--name</B>&nbsp;<I>connection-name</I><DD>
+<DT><B>--asynchronous<DD>
+</DL>
+<P>
+
+The initiate form of the whack</B> command will relay back from
+<B>pluto</B> status information via the UNIX domain socket (unless
+--asynchronous is specified).  The status information is meant to
+look a bit like that from <B>FTP</B>.  Currently <B>whack</B> simply
+copies this to stderr.  When the request is finished (eg. the SAs are
+established or <B>pluto</B> gives up), <B>pluto</B> closes the channel,
+causing <B>whack</B> to terminate.
+<P>
+
+The opportunistic initiate form is mainly used for debugging.
+<DL COMPACT>
+<DT><B>--tunnelipv4</B><DD>
+<DT><B>--tunnelipv6</B><DD>
+<DT><B>--oppohere</B>&nbsp;<I>ip-address</I><DD>
+<DT><B>--oppothere</B>&nbsp;<I>ip-address</I><DD>
+</DL>
+<P>
+
+This will cause <B>pluto</B> to attempt to opportunistically initiate a
+connection from here to the there, even if a previous attempt
+had been made.
+The whack log will show the progress of this attempt.
+<P>
+
+The terminate form tells <B>pluto</B> to delete any SAs that use the specified
+connection and to stop any negotiations in process.
+It does not prevent new negotiations from starting (the delete form
+has this effect).
+<DL COMPACT>
+<DT><B>--terminate</B><DD>
+<DT><B>--name</B>&nbsp;<I>connection-name</I><DD>
+</DL>
+<P>
+
+The public key for informs <B>pluto</B> of the RSA public key for a potential peer.
+Private keys must be kept secret, so they are kept in
+<I><A HREF="ipsec.secrets.5.html">ipsec.secrets</A></I>(5).
+
+<DL COMPACT>
+<DT><B>--keyid&nbsp;</B><I>id</I><DD>
+specififies the identity of the peer for which a public key should be used.
+Its form is identical to the identity in the connection.
+If no public key is specified, <B>pluto</B> attempts to find KEY records
+from DNS for the id (if a FQDN) or through reverse lookup (if an IP address).
+Note that there several interesting ways in which this is not secure.
+<DT><B>--addkey</B><DD>
+specifies that the new key is added to the collection; otherwise the
+new key replaces any old ones.
+<DT><B>--pubkeyrsa&nbsp;</B><I>key</I><DD>
+specifies the value of the RSA public key.  It is a sequence of bytes
+as described in RFC 2537 ``RSA/MD5 KEYs and SIGs in the Domain Name System (DNS)''.
+It is denoted in a way suitable for <I><A HREF="ipsec_ttodata.3.html">ipsec_ttodata</A></I>(3).
+For example, a base 64 numeral starts with 0s.
+</DL>
+<P>
+
+The listen form tells <B>pluto</B> to start listening for IKE requests
+on its public interfaces.  To avoid race conditions, it is normal to
+load the appropriate connections into <B>pluto</B> before allowing it
+to listen.  If <B>pluto</B> isn't listening, it is pointless to
+initiate negotiations, so it will refuse requests to do so.  Whenever
+the listen form is used, <B>pluto</B> looks for public interfaces and
+will notice when new ones have been added and when old ones have been
+removed.  This is also the trigger for <B>pluto</B> to read the
+<I>ipsec.secrets</I> file.  So listen may useful more than once.
+<DL COMPACT>
+<DT><B>--listen</B><DD>
+start listening for IKE traffic on public interfaces.
+<DT><B>--unlisten</B><DD>
+stop listening for IKE traffic on public interfaces.
+</DL>
+<P>
+
+The status form will display information about the internal state of
+<B>pluto</B>: information about each potential connection, about
+each state object, and about each shunt that <B>pluto</B> is managing
+without an associated connection.
+<DL COMPACT>
+<DT><B>--status</B><DD>
+</DL>
+<P>
+
+The shutdown form is the proper way to shut down <B>pluto</B>.
+It will tear down the SAs on this machine that <B>pluto</B> has negotiated.
+It does not inform its peers, so the SAs on their machines remain.
+<DL COMPACT>
+<DT><B>--shutdown</B><DD>
+</DL>
+<A NAME="lbAM">&nbsp;</A>
+<H3>Examples</H3>
+
+<P>
+
+It would be normal to start <B>pluto</B> in one of the system initialization
+scripts.  It needs to be run by the superuser.  Generally, no arguments are needed.
+To run in manually, the superuser can simply type
+<P>
+&nbsp;&nbsp;&nbsp;ipsec pluto
+<P>
+The command will immediately return, but a <B>pluto</B> process will be left
+running, waiting for requests from <B>whack</B> or a peer.
+<P>
+
+Using <B>whack</B>, several potential connections would be described:
+<DL COMPACT>
+<DT>
+
+&nbsp;&nbsp;&nbsp;ipsec whack --name&nbsp;silly
+--host&nbsp;127.0.0.1 --to --host&nbsp;127.0.0.2
+--ikelifetime&nbsp;900 --ipseclifetime&nbsp;800 --keyingtries&nbsp;3
+
+</DL>
+<P>
+
+<DD>Since this silly connection description specifies neither encryption,
+authentication, nor tunneling, it could only be used to establish
+an ISAKMP SA.
+<DL COMPACT>
+<DT>
+
+&nbsp;&nbsp;&nbsp;ipsec whack --name&nbsp;secret --host&nbsp;10.0.0.1 --client&nbsp;10.0.1.0/24
+--to --host&nbsp;10.0.0.2 --client&nbsp;10.0.2.0/24
+--encrypt
+
+</DL>
+<P>
+
+<DD>This is something that must be done on both sides.  If the other
+side is <B>pluto</B>, the same <B>whack</B> command could be used on it
+(the command syntax is designed to not distinguish which end is ours).
+<P>
+
+Now that the connections are specified, <B>pluto</B> is ready to handle
+requests and replies via the public interfaces.  We must tell it to discover
+those interfaces and start accepting messages from peers:
+<P>
+&nbsp;&nbsp;&nbsp;ipsec whack --listen
+<P>
+
+If we don't immediately wish to bring up a secure connection between
+the two clients, we might wish to prevent insecure traffic.
+The routing form asks <B>pluto</B> to cause the packets sent from
+our client to the peer's client to be routed through the ipsec0
+device; if there is no SA, they will be discarded:
+<P>
+&nbsp;&nbsp;&nbsp;ipsec whack --route secret
+<P>
+
+Finally, we are ready to get <B>pluto</B> to initiate negotiation
+for an IPsec SA (and implicitly, an ISAKMP SA):
+<P>
+&nbsp;&nbsp;&nbsp;ipsec whack --initiate&nbsp;--name&nbsp;secret
+<P>
+A small log of interesting events will appear on standard output
+(other logging is sent to syslog).
+<P>
+
+<B>whack</B> can also be used to terminate <B>pluto</B> cleanly, tearing down
+all SAs that it has negotiated.
+<P>
+&nbsp;&nbsp;&nbsp;ipsec whack --shutdown
+<P>
+Notification of any IPSEC SA deletion, but not ISAKMP SA deletion
+is sent to the peer.  Unfortunately, such Notification is not reliable.
+Furthermore, <B>pluto</B> itself ignores Notifications.
+<A NAME="lbAN">&nbsp;</A>
+<H3>The updown command</H3>
+
+<P>
+
+Whenever <B>pluto</B> brings a connection up or down, it invokes
+the updown command.  This command is specified using the <B>--updown</B>
+option.  This allows for customized control over routing and firewall manipulation.
+<P>
+
+The updown is invoked for five different operations.  Each of
+these operations can be for our client subnet or for our host itself.
+<DL COMPACT>
+<DT><B>prepare-host</B> or <B>prepare-client</B><DD>
+is run before bringing up a new connection if no other connection
+with the same clients is up.  Generally, this is useful for deleting a
+route that might have been set up before <B>pluto</B> was run or
+perhaps by some agent not known to <B>pluto</B>.
+<DT><B>route-host</B> or <B>route-client</B><DD>
+is run when bringing up a connection for a new peer client subnet
+(even if <B>prepare-host</B> or <B>prepare-client</B> was run).  The
+command should install a suitable route.  Routing decisions are based
+only on the destination (peer's client) subnet address, unlike eroutes
+which discriminate based on source too.
+<DT><B>unroute-host</B> or <B>unroute-client</B><DD>
+is run when bringing down the last connection for a particular peer
+client subnet.  It should undo what the <B>route-host</B> or <B>route-client</B>
+did.
+<DT><B>up-host</B> or <B>up-client</B><DD>
+is run when bringing up a tunnel eroute with a pair of client subnets
+that does not already have a tunnel eroute.
+This command should install firewall rules as appropriate.
+It is generally a good idea to allow IKE messages (UDP port 500)
+travel between the hosts.
+<DT><B>down-host</B> or <B>down-client</B><DD>
+is run when bringing down the eroute for a pair of client subnets.
+This command should delete firewall rules as appropriate.  Note that
+there may remain some inbound IPsec SAs with these client subnets.
+</DL>
+<P>
+
+The script is passed a large number of environment variables to specify
+what needs to be done.
+<DL COMPACT>
+<DT><B>PLUTO_VERSION</B><DD>
+indicates what version of this interface is being used.  This document
+describes version 1.1.  This is upwardly compatible with version 1.0.
+<DT><B>PLUTO_VERB</B><DD>
+specifies the name of the operation to be performed
+(<B>prepare-host</B>,r <B>prepare-client</B>,
+<B>up-host</B>, <B>up-client</B>,
+<B>down-host</B>, or <B>down-client</B>).  If the address family for
+security gateway to security gateway communications is IPv6, then
+a suffix of -v6 is added to the verb.
+<DT><B>PLUTO_CONNECTION</B><DD>
+is the name of the connection for which we are routing.
+<DT><B>PLUTO_NEXT_HOP</B><DD>
+is the next hop to which packets bound for the peer must be sent.
+<DT><B>PLUTO_INTERFACE</B><DD>
+is the name of the ipsec interface to be used.
+<DT><B>PLUTO_ME</B><DD>
+is the IP address of our host.
+<DT><B>PLUTO_MY_CLIENT</B><DD>
+is the IP address / count of our client subnet.
+If the client is just the host, this will be the host's own IP address / max
+(where max is 32 for IPv4 and 128 for IPv6).
+<DT><B>PLUTO_MY_CLIENT_NET</B><DD>
+is the IP address of our client net.
+If the client is just the host, this will be the host's own IP address.
+<DT><B>PLUTO_MY_CLIENT_MASK</B><DD>
+is the mask for our client net.
+If the client is just the host, this will be 255.255.255.255.
+<DT><B>PLUTO_PEER</B><DD>
+is the IP address of our peer.
+<DT><B>PLUTO_PEER_CLIENT</B><DD>
+is the IP address / count of the peer's client subnet.
+If the client is just the peer, this will be the peer's own IP address / max
+(where max is 32 for IPv4 and 128 for IPv6).
+<DT><B>PLUTO_PEER_CLIENT_NET</B><DD>
+is the IP address of the peer's client net.
+If the client is just the peer, this will be the peer's own IP address.
+<DT><B>PLUTO_PEER_CLIENT_MASK</B><DD>
+is the mask for the peer's client net.
+If the client is just the peer, this will be 255.255.255.255.
+</DL>
+<P>
+
+All output sent by the script to stderr or stdout is logged.  The
+script should return an exit status of 0 if and only if it succeeds.
+<P>
+
+<B>Pluto</B> waits for the script to finish and will not do any other
+processing while it is waiting.
+The script may assume that <B>pluto</B> will not change anything
+while the script runs.
+The script should avoid doing anything that takes much time and it
+should not issue any command that requires processing by <B>pluto</B>.
+Either of these activities could be performed by a background
+subprocess of the script.
+<A NAME="lbAO">&nbsp;</A>
+<H3>Rekeying</H3>
+
+<P>
+
+When an SA that was initiated by <B>pluto</B> has only a bit of
+lifetime left,
+<B>pluto</B> will initiate the creation of a new SA.  This applies to
+ISAKMP and IPsec SAs.
+The rekeying will be initiated when the SA's remaining lifetime is
+less than the rekeymargin plus a random percentage, between 0 and
+rekeyfuzz, of the rekeymargin.
+<P>
+
+Similarly, when an SA that was initiated by the peer has only a bit of
+lifetime left, <B>pluto</B> will try to initiate the creation of a
+replacement.
+To give preference to the initiator, this rekeying will only be initiated
+when the SA's remaining lifetime is half of rekeymargin.
+If rekeying is done by the responder, the roles will be reversed: the
+responder for the old SA will be the initiator for the replacement.
+The former initiator might also initiate rekeying, so there may
+be redundant SAs created.
+To avoid these complications, make sure that rekeymargin is generous.
+<P>
+
+One risk of having the former responder initiate is that perhaps
+none of its proposals is acceptable to the former initiator
+(they have not been used in a successful negotiation).
+To reduce the chances of this happening, and to prevent loss of security,
+the policy settings are taken from the old SA (this is the case even if
+the former initiator is initiating).
+These may be stricter than those of the connection.
+<P>
+
+<B>pluto</B> will not rekey an SA if that SA is not the most recent of its
+type (IPsec or ISAKMP) for its potential connection.
+This avoids creating redundant SAs.
+<P>
+
+The random component in the rekeying time (rekeyfuzz) is intended to
+make certain pathological patterns of rekeying unstable.  If both
+sides decide to rekey at the same time, twice as many SAs as necessary
+are created.  This could become a stable pattern without the
+randomness.
+<P>
+
+Another more important case occurs when a security gateway has SAs
+with many other security gateways.  Each of these connections might
+need to be rekeyed at the same time.  This would cause a high peek
+requirement for resources (network bandwidth, CPU time, entropy for
+random numbers).  The rekeyfuzz can be used to stagger the rekeying
+times.
+<P>
+
+Once a new set of SAs has been negotiated, <B>pluto</B> will never send
+traffic on a superseded one.  Traffic will be accepted on an old SA
+until it expires.
+<A NAME="lbAP">&nbsp;</A>
+<H3>Selecting a Connection When Responding: Road Warrior Support</H3>
+
+<P>
+
+When <B>pluto</B> receives an initial Main Mode message, it needs to
+decide which connection this message is for.  It picks based solely on
+the source and destination IP addresses of the message.  There might
+be several connections with suitable IP addresses, in which case one
+of them is arbitrarily chosen.  (The ISAKMP SA proposal contained in
+the message could be taken into account, but it is not.)
+<P>
+
+The ISAKMP SA is negotiated before the parties pass further
+identifying information, so all ISAKMP SA characteristics specified in
+the connection description should be the same for every connection
+with the same two host IP addresses.  At the moment, the only
+characteristic that might differ is authentication method.
+<P>
+
+Up to this point,
+all configuring has presumed that the IP addresses
+are known to all parties ahead of time.  This will not work
+when either end is mobile (or assigned a dynamic IP address for other
+reasons).  We call this situation ``Road Warrior''.  It is fairly tricky
+and has some important limitations, most of which are features of
+the IKE protocol.
+<P>
+
+Only the initiator may be mobile:
+the initiator may have an IP number unknown to the responder.  When
+the responder doesn't recognize the IP address on the first Main Mode
+packet, it looks for a connection with itself as one end and <B>%any</B>
+as the other.
+If it cannot find one, it refuses to negotiate.  If it
+does find one, it creates a temporary connection that is a duplicate
+except with the <B>%any</B> replaced by the source IP address from the
+packet; if there was no identity specified for the peer, the new IP
+address will be used.
+<P>
+
+When <B>pluto</B> is using one of these temporary connections and
+needs to find the preshared secret or RSA private key in <I>ipsec.secrets</I>,
+and and the connection specified no identity for the peer, <B>%any</B>
+is used as its identity.  After all, the real IP address was apparently
+unknown to the configuration, so it is unreasonable to require that
+it be used in this table.
+<P>
+
+Part way into the Phase 1 (Main Mode) negotiation using one of these
+temporary connection descriptions, <B>pluto</B> will be receive an
+Identity Payload.  At this point, <B>pluto</B> checks for a more
+appropriate connection, one with an identity for the peer that matches
+the payload but which would use the same keys so-far used for
+authentication.  If it finds one, it will switch to using this better
+connection (or a temporary derived from this, if it has <B>%any</B>
+for the peer's IP address).  It may even turn out that no connection
+matches the newly discovered identity, including the current connection;
+if so, <B>pluto</B> terminates negotiation.
+<P>
+
+Unfortunately, if preshared secret authentication is being used, the
+Identity Payload is encrypted using this secret, so the secret must be
+selected by the responder without knowing this payload.  This
+limits there to being at most one preshared secret for all Road Warrior
+systems connecting to a host.  RSA Signature authentications does not
+require that the responder know how to select the initiator's public key
+until after the initiator's Identity Payload is decoded (using the
+responder's private key, so that must be preselected).
+<P>
+
+When <B>pluto</B> is responding to a Quick Mode negotiation via one of these
+temporary connection descriptions, it may well find that the subnets
+specified by the initiator don't match those in the temporary
+connection description.  If so, it will look for a connection with
+matching subnets, its own host address, a peer address of <B>%any</B>
+and matching identities.
+If it finds one, a new temporary connection is derived from this one
+and used for the Quick Mode negotiation of IPsec SAs.  If it does not
+find one, <B>pluto</B> terminates negotiation.
+<P>
+
+Be sure to specify an appropriate nexthop for the responder
+to send a message to the initiator: <B>pluto</B> has no way of guessing
+it (if forwarding isn't required, use an explicit <B>%direct</B> as the nexthop
+and the IP address of the initiator will be filled in; the obsolete
+notation <B>0.0.0.0</B> is still accepted).
+<P>
+
+<B>pluto</B> has no special provision for the initiator side.  The current
+(possibly dynamic) IP address and nexthop must be used in defining
+connections.  These must be
+properly configured each time the initiator's IP address changes.
+<B>pluto</B> has no mechanism to do this automatically.
+<P>
+
+Although we call this Road Warrior Support, it could also be used to
+support encrypted connections with anonymous initiators.  The
+responder's organization could announce the preshared secret that would be used
+with unrecognized initiators and let anyone connect.  Of course the initiator's
+identity would not be authenticated.
+<P>
+
+If any Road Warrior connections are supported, <B>pluto</B> cannot
+reject an exchange initiated by an unknown host until it has
+determined that the secret is not shared or the signature is invalid.
+This must await the
+third Main Mode message from the initiator.  If no Road Warrior
+connection is supported, the first message from an unknown source
+would be rejected.  This has implications for ease of debugging
+configurations and for denial of service attacks.
+<P>
+
+Although a Road Warrior connection must be initiated by the mobile
+side, the other side can and will rekey using the temporary connection
+it has created.  If the Road Warrior wishes to be able to disconnect,
+it is probably wise to set <B>--keyingtries</B> to 1 in the
+connection on the non-mobile side to prevent it trying to rekey the
+connection.  Unfortunately, there is no mechanism to unroute the
+connection automatically.
+<A NAME="lbAQ">&nbsp;</A>
+<H3>Debugging</H3>
+
+<P>
+
+<B>pluto</B> accepts several optional arguments, useful mostly for debugging.
+Except for <B>--interface</B>, each should appear at most once.
+<DL COMPACT>
+<DT><B>--interface</B> <I>interfacename</I><DD>
+specifies that the named real public network interface should be considered.
+The interface name specified should not be <B>ipsec</B><I>N</I>.
+If the option doesn't appear, all interfaces are considered.
+To specify several interfaces, use the option once for each.
+One use of this option is to specify which interface should be used
+when two or more share the same IP address.
+<DT><B>--ikeport</B> <I>port-number</I><DD>
+changes the UDP port that <B>pluto</B> will use
+(default, specified by IANA: 500)
+<DT><B>--ctlbase</B> <I>path</I><DD>
+basename for control files.
+<I>path</I>.ctl is the socket through which <B>whack</B> communicates with
+<B>pluto</B>.
+<I>path</I>.pid is the lockfile to prevent multiple <B>pluto</B> instances.
+The default is <I>/var/run/pluto</I>).
+<DT><B>--secretsfile</B> <I>file</I><DD>
+specifies the file for authentication secrets
+(default: <I>/etc/ipsec.secrets</I>).
+This name is subject to ``globbing'' as in <I><A HREF="sh.1.html">sh</A></I>(1),
+so every file with a matching name is processed.
+Quoting is generally needed to prevent the shell from doing the globbing.
+<DT><B>--adns</B> <I>pathname</I><DD>
+<DT><B>--lwdnsq</B> <I>pathname</I><DD>
+specifies where to find <B>pluto</B>'s helper program for asynchronous DNS lookup.
+<B>pluto</B> can be built to use one of two helper programs: <B>_pluto_adns</B>
+or <B>lwdnsq</B>.  You must use the program for which it was built.
+By default, <B>pluto</B> will look for the program in
+<B>$IPSEC_DIR</B> (if that environment variable is defined) or, failing that,
+in the same directory as <B>pluto</B>.
+<DT><B>--nofork</B><DD>
+disable ``daemon fork'' (default is to fork).  In addition, after the
+lock file and control socket are created, print the line ``Pluto
+initialized'' to standard out.
+<DT><B>--noklips</B><DD>
+don't actually implement negotiated IPsec SAs
+<DT><B>--uniqueids</B><DD>
+if this option has been selected, whenever a new ISAKMP SA is
+established, any connection with the same Peer ID but a different
+Peer IP address is unoriented (causing all its SAs to be deleted).
+This helps clean up dangling SAs when a connection is lost and
+then regained at another IP address.
+<DT><B>--stderrlog</B><DD>
+log goes to standard out {default is to use <I><A HREF="syslogd.8.html">syslogd</A></I>(8))
+</DL>
+<P>
+
+For example
+<DL COMPACT>
+<DT>pluto --secretsfile&nbsp;ipsec.secrets --ctlbase&nbsp;pluto.base --ikeport&nbsp;8500 --nofork --noklips --stderrlog<DD>
+</DL>
+<P>
+
+lets one test <B>pluto</B> without using the superuser account.
+<P>
+
+<B>pluto</B> is willing to produce a prodigious amount of debugging
+information.  To do so, it must be compiled with -DDEBUG.  There are
+several classes of debugging output, and <B>pluto</B> may be directed to
+produce a selection of them.  All lines of
+debugging output are prefixed with ``|&nbsp;'' to distinguish them from error
+messages.
+<P>
+
+When <B>pluto</B> is invoked, it may be given arguments to specify
+which classes to output.  The current options are:
+<DL COMPACT>
+<DT><B>--debug-raw</B><DD>
+show the raw bytes of messages
+<DT><B>--debug-crypt</B><DD>
+show the encryption and decryption of messages
+<DT><B>--debug-parsing</B><DD>
+show the structure of input messages
+<DT><B>--debug-emitting</B><DD>
+show the structure of output messages
+<DT><B>--debug-control</B><DD>
+show <B>pluto</B>'s decision making
+<DT><B>--debug-lifecycle</B><DD>
+[this option is temporary] log more detail of lifecycle of SAs
+<DT><B>--debug-klips</B><DD>
+show <B>pluto</B>'s interaction with <B>KLIPS</B>
+<DT><B>--debug-dns</B><DD>
+show <B>pluto</B>'s interaction with <B>DNS</B> for KEY and TXT records
+<DT><B>--debug-oppo</B><DD>
+show why <B>pluto</B> didn't find a suitable DNS TXT record to authorize opportunistic initiation
+<DT><B>--debug-all</B><DD>
+all of the above
+<DT><B>--debug-private</B><DD>
+allow debugging output with private keys.
+<DT><B>--debug-none</B><DD>
+none of the above
+</DL>
+<P>
+
+The debug form of the
+<B>whack</B> command will change the selection in a running
+<B>pluto</B>.
+If a connection name is specified, the flags are added whenever
+<B>pluto</B> has identified that it is dealing with that connection.
+Unfortunately, this is often part way into the operation being observed.
+<P>
+
+For example, to start a <B>pluto</B> with a display of the structure of input
+and output:
+<DL COMPACT>
+<DT><DD>
+pluto --debug-emitting --debug-parsing
+</DL>
+<P>
+
+To later change this <B>pluto</B> to only display raw bytes:
+<DL COMPACT>
+<DT><DD>
+whack --debug-raw
+</DL>
+<P>
+
+For testing, SSH's IKE test page is quite useful:
+<DL COMPACT>
+<DT><DD>
+<I><A HREF="http://isakmp-test.ssh.fi/">http://isakmp-test.ssh.fi/</A></I>
+</DL>
+<P>
+
+Hint: ISAKMP SAs are often kept alive by IKEs even after the IPsec SA
+is established.  This allows future IPsec SA's to be negotiated
+directly.  If one of the IKEs is restarted, the other may try to use
+the ISAKMP SA but the new IKE won't know about it.  This can lead to
+much confusion.  <B>pluto</B> is not yet smart enough to get out of such a
+mess.
+<A NAME="lbAR">&nbsp;</A>
+<H3>Pluto's Behaviour When Things Go Wrong</H3>
+
+<P>
+
+When <B>pluto</B> doesn't understand or accept a message, it just
+ignores the message.  It is not yet capable of communicating the
+problem to the other IKE daemon (in the future it might use
+Notifications to accomplish this in many cases).  It does log a diagnostic.
+<P>
+
+When <B>pluto</B> gets no response from a message, it resends the same
+message (a message will be sent at most three times).  This is
+appropriate: UDP is unreliable.
+<P>
+
+When pluto gets a message that it has already seen, there are many
+cases when it notices and discards it.  This too is appropriate for UDP.
+<P>
+
+Combine these three rules, and you can explain many apparently
+mysterious behaviours.  In a <B>pluto</B> log, retrying isn't usually the
+interesting event.  The critical thing is either earlier (<B>pluto</B>
+got a message which it didn't like and so ignored, so it was still
+awaiting an acceptable message and got impatient) or on the other
+system (<B>pluto</B> didn't send a reply because it wasn't happy with
+the previous message).
+<A NAME="lbAS">&nbsp;</A>
+<H3>Notes</H3>
+
+<P>
+
+If <B>pluto</B> is compiled without -DKLIPS, it negotiates Security
+Associations but never ask the kernel to put them in place and never
+makes routing changes.  This allows <B>pluto</B> to be tested on systems
+without <B>KLIPS</B>, but makes it rather useless.
+<P>
+
+Each IPsec SA is assigned an SPI, a 32-bit number used to refer to the SA.
+The IKE protocol lets the destination of the SA choose the SPI.
+The range 0 to 0xFF is reserved for IANA.
+<B>Pluto</B> also avoids choosing an SPI in the range 0x100 to 0xFFF,
+leaving these SPIs free for manual keying.
+Remember that the peer, if not <B>pluto</B>, may well chose
+SPIs in this range.
+<A NAME="lbAT">&nbsp;</A>
+<H3>Policies</H3>
+
+<P>
+
+This catalogue of policies may be of use when trying to configure
+<B>Pluto</B> and another IKE implementation to interoperate.
+<P>
+
+In Phase 1, only Main Mode is supported.  We are not sure that
+Aggressive Mode is secure.  For one thing, it does not support
+identity protection.  It may allow more severe Denial Of Service
+attacks.
+<P>
+
+No Informational Exchanges are supported.  These are optional and
+since their delivery is not assured, they must not matter.
+It is the case that some IKE implementations won't interoperate
+without Informational Exchanges, but we feel they are broken.
+<P>
+
+No Informational Payloads are supported.  These are optional, but
+useful.  It is of concern that these payloads are not authenticated in
+Phase 1, nor in those Phase 2 messages authenticated with <A HREF="HASH.3.html">HASH</A>(3).
+<DL COMPACT>
+<DT>*<DD>
+Diffie Hellman Groups MODP 1024 and MODP 1536 (2 and 5)
+are supported.
+Group MODP768 (1) is not supported because it is too weak.
+<DT>*<DD>
+Host authetication can be done by RSA Signatures or Pre-Shared
+Secrets.
+<DT>*<DD>
+3DES CBC (Cypher Block Chaining mode) is the only encryption
+supported, both for ISAKMP SAs and IPSEC SAs.
+<DT>*<DD>
+MD5 and SHA1 hashing are supported for packet authentication in both
+kinds of SAs.
+<DT>*<DD>
+The ESP, AH, or AH plus ESP are supported.  If, and only if, AH and
+ESP are combined, the ESP need not have its own authentication
+component.  The selection is controlled by the --encrypt and
+--authenticate flags.
+<DT>*<DD>
+Each of these may be combined with IPCOMP Deflate compression,
+but only if the potential connection specifies compression and only
+if KLIPS is configured with IPCOMP support.
+<DT>*<DD>
+The IPSEC SAs may be tunnel or transport mode, where appropriate.
+The --tunnel flag controls this when <B>pluto</B> is initiating.
+<DT>*<DD>
+When responding to an ISAKMP SA proposal, the maximum acceptable
+lifetime is eight hours.  The default is one hour.  There is no
+minimum.  The --ikelifetime flag controls this when <B>pluto</B>
+is initiating.
+<DT>*<DD>
+When responding to an IPSEC SA proposal, the maximum acceptable
+lifetime is one day.  The default is eight hours.  There is no
+minimum.  The --ipseclifetime flag controls this when <B>pluto</B>
+is initiating.
+<DT>*<DD>
+PFS is acceptable, and will be proposed if the --pfs flag was
+specified.  The DH group proposed will be the same as negotiated for
+Phase 1.
+</DL>
+<A NAME="lbAU">&nbsp;</A>
+<H2>SIGNALS</H2>
+
+<P>
+
+<B>Pluto</B> responds to <B>SIGHUP</B> by issuing a suggestion that ``<B>whack</B>
+--listen'' might have been intended.
+<P>
+
+<B>Pluto</B> exits when it recieves <B>SIGTERM</B>.
+<A NAME="lbAV">&nbsp;</A>
+<H2>EXIT STATUS</H2>
+
+<P>
+
+<B>pluto</B> normally forks a daemon process, so the exit status is
+normally a very preliminary result.
+<DL COMPACT>
+<DT>0<DD>
+means that all is OK so far.
+<DT>1<DD>
+means that something was wrong.
+<DT>10<DD>
+means that the lock file already exists.
+</DL>
+<P>
+
+If <B>whack</B> detects a problem, it will return an exit status of 1.
+If it received progress messages from <B>pluto</B>, it returns as status
+the value of the numeric prefix from the last such message
+that was not a message sent to syslog or a comment
+(but the prefix for success is treated as 0).
+Otherwise, the exit status is 0.
+<A NAME="lbAW">&nbsp;</A>
+<H2>FILES</H2>
+
+<I>/var/run/pluto.pid</I>
+<BR>
+
+<I>/var/run/pluto.ctl</I>
+<BR>
+
+<I>/etc/ipsec.secrets</I>
+<BR>
+
+<I>$IPSEC_LIBDIR/_pluto_adns</I>
+<BR>
+
+<I>$IPSEC_EXECDIR/lwdnsq</I>
+<BR>
+
+<I>/dev/urandom</I>
+<A NAME="lbAX">&nbsp;</A>
+<H2>ENVIRONMENT</H2>
+
+<I>IPSEC_LIBDIR</I>
+<BR>
+
+<I>IPSEC_EXECDIR</I>
+<BR>
+
+<I>IPSECmyid</I>
+<A NAME="lbAY">&nbsp;</A>
+<H2>SEE ALSO</H2>
+
+<P>
+
+The rest of the FreeS/WAN distribution, in particular <I><A HREF="ipsec.8.html">ipsec</A></I>(8).
+<P>
+
+<I><A HREF="ipsec_auto.8.html">ipsec_auto</A></I>(8) is designed to make using <B>pluto</B> more pleasant.
+Use it!
+<P>
+
+<I><A HREF="ipsec.secrets.5.html">ipsec.secrets</A></I>(5)
+
+describes the format of the secrets file.
+<P>
+
+<I><A HREF="ipsec_atoaddr.3.html">ipsec_atoaddr</A></I>(3), part of the FreeS/WAN distribution, describes the
+forms that IP addresses may take.
+<I><A HREF="ipsec_atosubnet.3.html">ipsec_atosubnet</A></I>(3), part of the FreeS/WAN distribution, describes the
+forms that subnet specifications.
+<P>
+
+For more information on IPsec, the mailing list, and the relevant
+documents, see:
+<DL COMPACT>
+<DT><DD>
+
+<I><A HREF="http://www.ietf.cnri.reston.va.us/html.charters/ipsec-charter.html">http://www.ietf.cnri.reston.va.us/html.charters/ipsec-charter.html</A></I>
+
+</DL>
+<P>
+
+At the time of writing, the most relevant IETF RFCs are:
+<DL COMPACT>
+<DT><DD>
+RFC2409 The Internet Key Exchange (IKE)
+<DT><DD>
+RFC2408 Internet Security Association and Key Management Protocol (ISAKMP)
+<DT><DD>
+RFC2407 The Internet IP Security Domain of Interpretation for ISAKMP
+</DL>
+<P>
+
+The FreeS/WAN web site &lt;<A HREF="htp://www.freeswan.org">htp://www.freeswan.org</A>&gt;
+and the mailing lists described there.
+<A NAME="lbAZ">&nbsp;</A>
+<H2>HISTORY</H2>
+
+This code is released under the GPL terms.
+See the accompanying file COPYING-2.0 for more details.
+The GPL does NOT apply to those pieces of code written by others
+which are included in this distribution, except as noted by the
+individual authors.
+<P>
+
+This software was originally written
+for the FreeS/WAN project
+&lt;<A HREF="http://www.freeswan.org">http://www.freeswan.org</A>&gt;
+by Angelos D. Keromytis
+(<A HREF="mailto:angelos@dsl.cis.upenn.edu">angelos@dsl.cis.upenn.edu</A>), in May/June 1997, in Athens, Greece.
+Thanks go to John Ioannidis for his help.
+<P>
+
+It is currently (2000)
+being developed and maintained by D. Hugh Redelmeier
+(<A HREF="mailto:hugh@mimosa.com">hugh@mimosa.com</A>), in Canada.  The regulations of Greece and Canada
+allow us to make the code freely redistributable.
+<P>
+
+Kai Martius (<A HREF="mailto:admin@imib.med.tu-dresden.de">admin@imib.med.tu-dresden.de</A>) contributed the initial
+version of the code supporting PFS.
+<P>
+
+Richard Guy Briggs &lt;<A HREF="mailto:rgb@conscoop.ottawa.on.ca">rgb@conscoop.ottawa.on.ca</A>&gt; and Peter Onion
+&lt;<A HREF="mailto:ponion@srd.bt.co.uk">ponion@srd.bt.co.uk</A>&gt; added the PFKEY2 support.
+<P>
+
+We gratefully acknowledge that we use parts of Eric Young's <I>libdes</I>
+package; see <I>../libdes/COPYRIGHT</I>.
+<A NAME="lbBA">&nbsp;</A>
+<H2>BUGS</H2>
+
+<B>pluto</B>
+
+is a work-in-progress.  It currently has many limitations.
+For example, it ignores notification messages that it receives, and
+it generates only Delete Notifications and those only for IPSEC SAs.
+<P>
+
+<B>pluto</B> does not support the Commit Flag.
+The Commit Flag is a bad feature of the IKE protocol.
+It isn't protected -- neither encrypted nor authenticated.
+A man in the middle could turn it on, leading to DoS.
+We just ignore it, with a warning.
+This should let us interoperate with
+implementations that insist on it, with minor damage.
+<P>
+
+<B>pluto</B> does not check that the SA returned by the Responder
+is actually one that was proposed.  It only checks that the SA is
+acceptable.  The difference is not large, but can show up in attributes
+such as SA lifetime.
+<P>
+
+There is no good way for a connection to be automatically terminated.
+This is a problem for Road Warrior and Opportunistic connections.
+The <B>--dontrekey</B> option does prevent the SAs from
+being rekeyed on expiry.
+Additonally, if a Road Warrior connection has a client subnet with a fixed IP
+address, a negotiation with that subnet will cause any other
+connection instantiations with that same subnet to be unoriented
+(deleted, in effect).
+See also the --uniqueids option for an extension of this.
+<P>
+
+When <B>pluto</B> sends a message to a peer that has disappeared,
+<B>pluto</B> receives incomplete information from the kernel, so it
+logs the unsatisfactory message ``some IKE message we sent has been
+rejected with ECONNREFUSED (kernel supplied no details)''.  John
+Denker suggests that this command is useful for tracking down the
+source of these problems:
+<BR>
+
+<TT>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TT>tcpdump -i eth0 icmp[0] != 8 and icmp[0] != 0<BR>
+<BR>
+
+Substitute your public interface for eth0 if it is different.
+<P>
+
+The word ``authenticate'' is used for two different features.  We must
+authenticate each IKE peer to the other.  This is an important task of
+Phase 1.  Each packet must be authenticated, both in IKE and in IPsec,
+and the method for IPsec is negotiated as an AH SA or part of an ESP SA.
+Unfortunately, the protocol has no mechanism for authenticating the Phase 2
+identities.
+<P>
+
+Bugs should be reported to the &lt;<A HREF="mailto:users@lists.freeswan.org">users@lists.freeswan.org</A>&gt; mailing list.
+Caution: we cannot accept
+actual code from US residents, or even US citizens living outside the
+US, because that would bring FreeS/WAN under US export law.  Some
+other countries cause similar problems.  In general, we would prefer
+that you send detailed problem reports rather than code:  we want
+FreeS/WAN to be unquestionably freely exportable, which means being
+very careful about where the code comes from, and for a small bug fix,
+that is often more time-consuming than just reinventing the fix
+ourselves.
+<P>
+
+<HR>
+<A NAME="index">&nbsp;</A><H2>Index</H2>
+<DL>
+<DT><A HREF="#lbAB">NAME</A><DD>
+<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
+<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
+<DL>
+<DT><A HREF="#lbAE">IKE's Job</A><DD>
+<DT><A HREF="#lbAF">Pluto</A><DD>
+<DT><A HREF="#lbAG">Before Running Pluto</A><DD>
+<DT><A HREF="#lbAH">Setting up <B>KLIPS</B> for <B>pluto</B></A><DD>
+<DT><A HREF="#lbAI">ipsec.secrets file</A><DD>
+<DT><A HREF="#lbAJ">Running Pluto</A><DD>
+<DT><A HREF="#lbAK">Pluto's Internal State</A><DD>
+<DT><A HREF="#lbAL">Using Whack</A><DD>
+<DT><A HREF="#lbAM">Examples</A><DD>
+<DT><A HREF="#lbAN">The updown command</A><DD>
+<DT><A HREF="#lbAO">Rekeying</A><DD>
+<DT><A HREF="#lbAP">Selecting a Connection When Responding: Road Warrior Support</A><DD>
+<DT><A HREF="#lbAQ">Debugging</A><DD>
+<DT><A HREF="#lbAR">Pluto's Behaviour When Things Go Wrong</A><DD>
+<DT><A HREF="#lbAS">Notes</A><DD>
+<DT><A HREF="#lbAT">Policies</A><DD>
+</DL>
+<DT><A HREF="#lbAU">SIGNALS</A><DD>
+<DT><A HREF="#lbAV">EXIT STATUS</A><DD>
+<DT><A HREF="#lbAW">FILES</A><DD>
+<DT><A HREF="#lbAX">ENVIRONMENT</A><DD>
+<DT><A HREF="#lbAY">SEE ALSO</A><DD>
+<DT><A HREF="#lbAZ">HISTORY</A><DD>
+<DT><A HREF="#lbBA">BUGS</A><DD>
+</DL>
+<HR>
+This document was created by
+<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
+using the manual pages.<BR>
+Time: 21:40:18 GMT, November 11, 2003
+</BODY>
+</HTML>
diff --git a/doc/manpages.html b/doc/manpages.html
new file mode 100644
index 000000000..81ca11ae0
--- /dev/null
+++ b/doc/manpages.html
@@ -0,0 +1,145 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
+H5 { font-family: sans-serif }
+H6 { font-family: sans-serif }
+SUB { font-size: smaller }
+SUP { font-size: smaller }
+PRE { font-family: monospace }
+--></STYLE>
+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="faq.html">Previous</A>
+<A HREF="firewall.html">Next</A>
+<HR>
+<H1><A name="manpages">FreeS/WAN manual pages</A></H1>
+<P>The various components of Linux FreeS/WAN are of course documented in
+ standard Unix manual pages, accessible via the man(1) command.</P>
+<P>Links here take you to an HTML version of the man pages.</P>
+<H2><A name="man.file">Files</A></H2>
+<DL>
+<DT><A href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</A></DT>
+<DD>IPsec configuration and connections</DD>
+<DT><A href="manpage.d/ipsec.secrets.5.html">ipsec.secrets(5)</A></DT>
+<DD>secrets for IKE authentication, either pre-shared keys or RSA
+ private keys</DD>
+</DL>
+<P>These files are also discussed in the<A href="config.html">
+ configuration</A> section.</P>
+<H2><A name="man.command">Commands</A></H2>
+<P>Many users will never give most of the FreeS/WAN commands directly.
+ Configure the files listed above correctly and everything should be
+ automatic.</P>
+<P>The exceptions are commands for mainpulating the<A href="glossary.html#RSA">
+ RSA</A> keys used in Pluto authentication:</P>
+<DL>
+<DT><A href="manpage.d/ipsec_rsasigkey.8.html">ipsec_rsasigkey(8)</A></DT>
+<DD>generate keys</DD>
+<DT><A href="manpage.d/ipsec_newhostkey.8.html">ipsec_newhostkey(8)</A></DT>
+<DD>generate keys in a convenient format</DD>
+<DT><A href="manpage.d/ipsec_showhostkey.8.html">ipsec_showhostkey(8)</A>
+</DT>
+<DD>extract<A href="glossary.html#RSA"> RSA</A> keys from<A href="manpage.d/ipsec.secrets.5.html">
+ ipsec.secrets(5)</A> (or optionally, another file) and format them for
+ insertion in<A href="manpage.d/ipsec.conf.5.html"> ipsec.conf(5)</A> or
+ in DNS records</DD>
+</DL>
+<P>Note that:</P>
+<UL>
+<LI>These keys are for<STRONG> authentication only</STRONG>. They are<STRONG>
+ not secure for encryption</STRONG>.</LI>
+<LI>The utility uses random(4) as a source of<A href="glossary.html#random">
+ random numbers</A>. This may block for some time if there is not enough
+ activity on the machine to provide the required entropy. You may want
+ to give it some bogus activity such as random mouse movements or some
+ command such as<NOBR> <TT>du /usr &gt; /dev/null &amp;</TT>.</LI>
+</UL>
+<P>The following commands are fairly likely to be used, if only for
+ testing and status checks:</P>
+<DL>
+<DT><A href="manpage.d/ipsec.8.html">ipsec(8)</A></DT>
+<DD>invoke IPsec utilities</DD>
+<DT><A href="manpage.d/ipsec_setup.8.html">ipsec_setup(8)</A></DT>
+<DD>control IPsec subsystem</DD>
+<DT><A href="manpage.d/ipsec_auto.8.html">ipsec_auto(8)</A></DT>
+<DD>control automatically-keyed IPsec connections</DD>
+<DT><A href="manpage.d/ipsec_manual.8.html">ipsec_manual(8)</A></DT>
+<DD>take manually-keyed IPsec connections up and down</DD>
+<DT><A href="manpage.d/ipsec_ranbits.8.html">ipsec_ranbits(8)</A></DT>
+<DD>generate random bits in ASCII form</DD>
+<DT><A href="manpage.d/ipsec_look.8.html">ipsec_look(8)</A></DT>
+<DD>show minimal debugging information</DD>
+<DT><A href="manpage.d/ipsec_barf.8.html">ipsec_barf(8)</A></DT>
+<DD>spew out collected IPsec debugging information</DD>
+</DL>
+<P>The lower-level utilities listed below are normally invoked via
+ scripts listed above, but they can also be used directly when required.</P>
+<DL>
+<DT><A href="manpage.d/ipsec_eroute.8.html">ipsec_eroute(8)</A></DT>
+<DD>manipulate IPsec extended routing tables</DD>
+<DT><A href="manpage.d/ipsec_klipsdebug.8.html">ipsec_klipsdebug(8)</A></DT>
+<DD>set Klips (kernel IPsec support) debug features and level</DD>
+<DT><A href="manpage.d/ipsec_pluto.8.html">ipsec_pluto(8)</A></DT>
+<DD>IPsec IKE keying daemon</DD>
+<DT><A href="manpage.d/ipsec_spi.8.html">ipsec_spi(8)</A></DT>
+<DD>manage IPsec Security Associations</DD>
+<DT><A href="manpage.d/ipsec_spigrp.8.html">ipsec_spigrp(8)</A></DT>
+<DD>group/ungroup IPsec Security Associations</DD>
+<DT><A href="manpage.d/ipsec_tncfg.8.html">ipsec_tncfg(8)</A></DT>
+<DD>associate IPsec virtual interface with real interface</DD>
+<DT><A href="manpage.d/ipsec_whack.8.html">ipsec_whack(8)</A></DT>
+<DD>control interface for IPsec keying daemon</DD>
+</DL>
+<H2><A name="man.lib">Library routines</A></H2>
+<DL>
+<DT><A href="manpage.d/ipsec_atoaddr.3.html">ipsec_atoaddr(3)</A></DT>
+<DT><A href="manpage.d/ipsec_addrtoa.3.html">ipsec_addrtoa(3)</A></DT>
+<DD>convert Internet addresses to and from ASCII</DD>
+<DT><A href="manpage.d/ipsec_atosubnet.3.html">ipsec_atosubnet(3)</A></DT>
+<DT><A href="manpage.d/ipsec_subnettoa.3.html">ipsec_subnettoa(3)</A></DT>
+<DD>convert subnet/mask ASCII form to and from addresses</DD>
+<DT><A href="manpage.d/ipsec_atoasr.3.html">ipsec_atoasr(3)</A></DT>
+<DD>convert ASCII to Internet address, subnet, or range</DD>
+<DT><A href="manpage.d/ipsec_rangetoa.3.html">ipsec_rangetoa(3)</A></DT>
+<DD>convert Internet address range to ASCII</DD>
+<DT>ipsec_atodata(3)</DT>
+<DT><A href="manpage.d/ipsec_datatoa.3.html">ipsec_datatoa(3)</A></DT>
+<DD>convert binary data from and to ASCII formats</DD>
+<DT><A href="manpage.d/ipsec_atosa.3.html">ipsec_atosa(3)</A></DT>
+<DT><A href="manpage.d/ipsec_satoa.3.html">ipsec_satoa(3)</A></DT>
+<DD>convert IPsec Security Association IDs to and from ASCII</DD>
+<DT><A href="manpage.d/ipsec_atoul.3.html">ipsec_atoul(3)</A></DT>
+<DT><A href="manpage.d/ipsec_ultoa.3.html">ipsec_ultoa(3)</A></DT>
+<DD>convert unsigned-long numbers to and from ASCII</DD>
+<DT><A href="manpage.d/ipsec_goodmask.3.html">ipsec_goodmask(3)</A></DT>
+<DD>is this Internet subnet mask a valid one?</DD>
+<DT><A href="manpage.d/ipsec_masktobits.3.html">ipsec_masktobits(3)</A></DT>
+<DD>convert Internet subnet mask to bit count</DD>
+<DT><A href="manpage.d/ipsec_bitstomask.3.html">ipsec_bitstomask(3)</A></DT>
+<DD>convert bit count to Internet subnet mask</DD>
+<DT><A href="manpage.d/ipsec_optionsfrom.3.html">ipsec_optionsfrom(3)</A>
+</DT>
+<DD>read additional ``command-line'' options from file</DD>
+<DT><A href="manpage.d/ipsec_subnetof.3.html">ipsec_subnetof(3)</A></DT>
+<DD>given Internet address and subnet mask, return subnet number</DD>
+<DT><A href="manpage.d/ipsec_hostof.3.html">ipsec_hostof(3)</A></DT>
+<DD>given Internet address and subnet mask, return host part</DD>
+<DT><A href="manpage.d/ipsec_broadcastof.3.html">ipsec_broadcastof(3)</A>
+</DT>
+<DD>given Internet address and subnet mask, return broadcast address</DD>
+</DL>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="faq.html">Previous</A>
+<A HREF="firewall.html">Next</A>
+</BODY>
+</HTML>
diff --git a/doc/nightly.html b/doc/nightly.html
new file mode 100644
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+++ b/doc/nightly.html
@@ -0,0 +1,125 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
+H5 { font-family: sans-serif }
+H6 { font-family: sans-serif }
+SUB { font-size: smaller }
+SUP { font-size: smaller }
+PRE { font-family: monospace }
+--></STYLE>
+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="makecheck.html">Previous</A>
+<HR>
+<H1><A name="nightly">Nightly regression testing</A></H1>
+<P> The nightly regression testing system consists of several shell
+ scripts and some perl scripts. The goal is to check out a fresh tree,
+ run &quot;make check&quot; on it, record the results and summarize the results to
+ the team and to the web site.</P>
+<P> Output can be found on<A HREF="http://bugs.freeswan.org:81/"> adams</A>
+, although the tests are actually run on another project machine.</P>
+<H1><A name="nightlyhowto">How to setup the nightly build</A></H1>
+<P> The best way to do nightly testing is to setup a new account. We
+ call the account &quot;build&quot; - you could call it something else, but there
+ may still be some references to ~build in the scripts.</P>
+<H2><A NAME="42_1"> Files you need to know about</A></H2>
+<P> As few files as possible need to be extracted from the source tree -
+ files are run from the source tree whenever possible. However, there
+ are some bootstrap and configuration files that are necessary.</P>
+<P> There are 7 files in testing/utils that are involved:</P>
+<DL>
+<DT> nightly-sample.sh</DT>
+<DD> This is the root of the build process. This file should be copied
+ out of the CVS tree, to $HOME/bin/nightly.sh of the build account. This
+ file should be invoked from cron.</DD>
+<DT> freeswan-regress-env-sample.sh</DT>
+<DD> This file should be copied to $HOME/freeswan-regress-env.sh. It
+ should be edited to localize the values. See below.</DD>
+<DT> regress-cleanup.pl</DT>
+<DD> This file needs to be copied to $HOME/bin/regress-cleanup.pl. It is
+ invoked by the nightly file before doing anything else. It removes
+ previous nights builds in order to free up disk space for the build
+ about to be done.</DD>
+<DT> teammail-sample.sh</DT>
+<DD> A script used to send results email to the &quot;team&quot;. This sample
+ script could be copied to $HOME/bin/teammail.sh. This version will PGP
+ encrypt all the output to the team members. If this script is used,
+ then PGP will have to be properly setup to have the right keys.</DD>
+<DT> regress-nightly.sh</DT>
+<DD> This is the first stage of the nightly build. This stage will call
+ other scripts as appropriate, and will extract the source code from
+ CVS. This script should be copied to $HOME/bin/regress-nightly.sh</DD>
+<DT> regress-stage2.sh</DT>
+<DD> This is the second stage of the nightly build. It is called in
+ place. It essentially sets up the UML setup in umlsetup.sh, and calls
+ &quot;make check&quot;.</DD>
+<DT> regress-summarize-results.pl</DT>
+<DD> This script will summarize the results from the tests to a
+ permanent directory set by $REGRESSRESULTS. It is invoked from the
+ stage2 nightly script.</DD>
+<DT> regress-chart.sh</DT>
+<DD> This script is called at the end of the build process, and will
+ summarize each night's results (as saved into $REGRESSRESULTS by
+ regress-summarize-results.pl) as a chart using gnuplot. Note that this
+ requires at least gnuplot 3.7.2.</DD>
+</DL>
+<H2><A NAME="42_2">Configuring freeswan-regress-env.sh</A></H2>
+<P>For more info on KERNPOOL, UMLPATCH, BASICROOT and SHAREDIR, see<A HREF="umltesting.html">
+ User-Mode-Linux testing guide</A>.</P>
+<DL>
+<DT> KERNPOOL</DT>
+<DD> Extract copy of some kernel source to be used for UML builds</DD>
+<DT> UMLPATCH</DT>
+<DD> matching User-Mode-Linux patch.</DD>
+<DT> BASICROOT</DT>
+<DD> the root file system image (see<A HREF="umltesting.html">
+ User-Mode-Linux testing guide</A>).</DD>
+<DT> SHAREDIR=${BASICROOT}/usr/share</DT>
+<DD> The /usr/share to use.</DD>
+<DT> REGRESSTREE</DT>
+<DD> A directory in which to store the nightly regression results.
+ Directories will be created by date in this tree.</DD>
+<DT> TCPDUMP=tcpdump-3.7.1</DT>
+<DD> The path to the<A HREF="http://www.tcpdump.org/"> tcpdump</A> to
+ use. This must have crypto compiled in, and must be at least 3.7.1</DD>
+<DT> KERNEL_RH7_2_SRC=/a3/kernel_sources/linux-2.4.9-13/</DT>
+<DD> An extracted copy of the RedHat 7.2. kernel source. If set, then
+ the packaging/rpm-rh72-install-01 test will be run, and an RPM will be
+ built as a test.</DD>
+<DT> KERNEL_RH7_3_SRC=/a3/kernel_sources/rh/linux-2.4.18-5</DT>
+<DD> An extracted copy of the RedHat 7.3. kernel source. If set, then
+ the packaging/rpm-rh73-install-01 test will be run, and an RPM will be
+ built as a test.</DD>
+<DT> NIGHTLY_WATCHERS=&quot;userid,userid,userid&quot;</DT>
+<DD> The list of people who should receive nightly output. This is used
+ by teammail.sh</DD>
+<DT> FAILLINES=128</DT>
+<DD> How many lines of failed test output to include in the nightly
+ output</DD>
+<DT> PATH=$PATH:/sandel/bin export PATH</DT>
+<DD> You can also override the path if necessary here.</DD>
+<DT> CVSROOT=:pserver:anoncvs@ip212.xs4net.freeswan.org:/freeswan/MASTER</DT>
+<DD> The CVSROOT to use. This example may work for anonymous CVS, but
+ will be 12 hours behind the primary, and is still experimental</DD>
+<DT> SNAPSHOTSIGDIR=$HOME/snapshot-sig</DT>
+<DD> For the release tools, where to put the generated per-snapshot
+ signature keys</DD>
+<DT> LASTREL=1.97</DT>
+<DD> the name of the last release branch (to find the right per-snapshot
+ signature</DD>
+<DD></DD>
+</DL>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="makecheck.html">Previous</A>
+</BODY>
+</HTML>
diff --git a/doc/oppimpl.txt b/doc/oppimpl.txt
new file mode 100644
index 000000000..fe4527d4e
--- /dev/null
+++ b/doc/oppimpl.txt
@@ -0,0 +1,514 @@
+Implementing Opportunistic Encryption
+
+Henry Spencer & D. Hugh Redelmeier
+
+Version 4+, 15 Dec 2000
+
+
+
+Updates
+
+Major changes since last version:  "Negotiation Issues" section discussing
+some interoperability matters, plus some wording cleanup.  Some issues
+arising from discussions at OLS are not yet resolved, so there will almost
+certainly be another version soon.
+
+xxx incoming could be opportunistic or RW.  xxx any way of saving unaware
+implementations???  xxx compression needs mention.
+
+
+
+Introduction
+
+A major long-term goal of the FreeS/WAN project is opportunistic
+encryption:  a security gateway intercepts an outgoing packet aimed at a
+new remote host, and quickly attempts to negotiate an IPsec tunnel to that
+host's security gateway, so that traffic can be encrypted and
+authenticated without changes to the host software.  (This generalizes
+trivially to the end-to-end case where host and security gateway are one
+and the same.)  If the attempt fails, the packet (or a retry thereof)
+passes through in clear or is dropped, depending on local policy. 
+Prearranged tunnels bypass all this, so static VPNs can coexist with
+opportunistic encryption. 
+
+xxx here Although significant intelligence about all this is necessary at the
+initiator end, it's highly desirable for little or no special machinery
+to be needed at the responder end.  In particular, if none were needed,
+then a security gateway which knows nothing about opportunistic encryption
+could nevertheless participate in some opportunistic connections.
+
+IPSEC gives us the low-level mechanisms, and the key-exchange machinery,
+but there are some vague spots (to put it mildly) at higher levels.
+
+One constraint which deserves comment is that the process of tunnel setup
+should be quick.  Moreover, the decision that no tunnel can be created
+should also be quick, since that will be a common case, at least in the
+beginning.  People will be reluctant to use opportunistic encryption if it
+causes gross startup delays on every connection, even connections which see
+no benefit from it.  Win or lose, the process must be rapid.
+
+There's nothing much we can do to speed up the key exchange itself.  (The
+one thing which conceivably might be done is to use Aggressive Mode, which
+involves fewer round trips, but it has limitations and possible security
+problems, and we're reluctant to touch it.)  What we can do, is to make the
+other parts of the setup process as quick as possible.  This desire will
+come back to haunt us below. :-)
+
+A further note is that we must consider the processing at the responder
+end as well as the initiator end.
+
+Several pieces of new machinery are needed to make this work.  Here's a
+brief list, with details considered below.
+
++ Outgoing Packet Interception.  KLIPS needs to intercept packets which
+likely would benefit from tunnel setup, and bring them to Pluto's
+attention.  There needs to be enough memory in the process that the same
+tunnel doesn't get proposed too often (win or lose). 
+
++ Smart Connection Management.  Not only do we need to establish tunnels
+on request, once a tunnel is set up, it needs to be torn down eventually
+if it's not in use.  It's also highly desirable to detect the fact that it
+has stopped working, and do something useful.  Status changes should be
+coordinated between the two security gateways unless one has crashed,
+and even then, they should get back into sync eventually.
+
++ Security Gateway Discovery.  Given a packet destination, we must decide
+who to attempt to negotiate a tunnel with.  This must be done quickly, win
+or lose, and reliably even in the presence of diverse network setups.
+
++ Authentication Without Prearrangement.  We need to be sure we're really
+talking to the intended security gateway, without being able to prearrange
+any shared information.  He needs the same assurance about us.
+
++ More Flexible Policy.  In particular, the responding Pluto needs a way
+to figure out whether the connection it is being asked to make is okay.
+This isn't as simple as just searching our existing conn database -- we
+probably have to specify *classes* of legitimate connections.
+
+Conveniently, we have a three-letter acronym for each of these. :-)
+
+Note on philosophy:  we have deliberately avoided providing six different
+ways to do each step, in favor of specifying one good one.  Choices are
+provided only when they appear to be necessary.  (Or when we are not yet
+quite sure yet how best to do something...)
+
+
+
+OPI, SCM
+
+Smart Connection Management would be quite useful even by itself,
+requiring manual triggering.  (Right now, we do the manual triggering, but
+not the other parts of SCM.)  Outgoing Packet Interception fits together
+with SCM quite well, and improves its usefulness further.  Going through a
+connection's life cycle from the start... 
+
+OPI itself is relatively straightforward, aside from the nagging question
+of whether the intercepted packet is put on hold and then released, or
+dropped.  Putting it on hold is preferable; the alternative is to rely on
+the application or the transport layer re-trying.  The downside of packet
+hold is extra resources; the downside of packet dropping is that IPSEC
+knows *when* the packet can finally go out, and the higher layers don't. 
+Either way, life gets a little tricky because a quickly-retrying
+application may try more than once before we know for sure whether a
+tunnel can be set up, and something has to detect and filter out the
+duplications.  Some ARP implementations use the approach of keeping one
+packet for an as-yet-unresolved address, and throwing away any more that
+appear; that seems a reasonable choice.
+
+(Is it worth intercepting *incoming* packets, from the outside world, and
+attempting tunnel setup based on them?  Perhaps... if, and only if, we
+organize AWP so that non-opportunistic SGs can do it somehow.  Otherwise,
+if the other end has not initiated tunnel setup itself, it will not be
+prepared to do so at our request.)
+
+Once a tunnel is up, packets going into it naturally are not intercepted
+by OPI.  However, we need to do something about the flip side of this too: 
+after deciding that we *cannot* set up a tunnel, either because we don't
+have enough information or because the other security gateway is
+uncooperative, we have to remember that for a while, so we don't keep
+knocking on the same locked door.  One plausible way of doing that is to
+set up a bypass "tunnel" -- the equivalent of our current %passthrough
+connection -- and have it managed like a real SCM tunnel (finite lifespan
+etc.).  This sounds a bit heavyweight, but in practice, the alternatives
+all end up doing something very similar when examined closely.  Note that
+we need an extra variant of this, a block rather than a bypass, to cover
+the case where local policy dictates that packets *not* be passed through;
+we still have to remember the fact that we can't set up a real tunnel.
+
+When to tear tunnels down is a bit problematic, but if we're setting up a
+potentially unbounded number of them, we have to tear them down *somehow*
+*sometime*.  It seems fairly obvious that we set a tentative lifespan,
+probably fairly short (say 1min), and when it expires, we look to see if
+the tunnel is still in use (say, has had traffic in the last half of the
+lifespan).  If so, we assign it a somewhat longer lifespan (say 10min),
+after which we look again.  If not, we close it down.  (This lifespan is
+independent of key lifetime; it is just the time when the tunnel's future
+is next considered.  This should happen reasonably frequently, unlike
+rekeying, which is costly and shouldn't be too frequent.)  Multi-step
+backoff algorithms probably are not worth the trouble; looking every
+10min doesn't seem onerous.
+
+For the tunnel-expiry decision, we need to know how long it has been since
+the last traffic went through.  A more detailed history of the traffic
+does not seem very useful; a simple idle timer (or last-traffic timestamp)
+is both necessary and sufficient.  And KLIPS already has this.
+
+As noted, default initial lifespan should be short.  However, Pluto should
+keep a history of recently-closed tunnels, to detect cases where a tunnel
+is being repeatedly re-established and should be given a longer lifespan. 
+(Not only is tunnel setup costly, but it adds user-visible delay, so
+keeping a tunnel alive is preferable if we have reason to suspect more
+traffic soon.)  Any tunnel re-established within 10min of dying should have
+10min added to its initial lifespan.  (Just leaving all tunnels open longer
+is unappealing -- adaptive lifetimes which are sensitive to the behavior
+of a particular tunnel are wanted.  Tunnels are relatively cheap entities
+for us, but that is not necessarily true of all implementations, and there
+may also be administrative problems in sorting through large accumulations
+of idle tunnels.)
+
+It might be desirable to have detailed information about the initial
+packet when determining lifespans.  HTTP connections in particular are
+notoriously bursty and repetitive. 
+
+Arguably it would be nice to monitor TCP connection status.  A still-open
+TCP connection is almost a guarantee that more traffic is coming, while
+the closing of the only TCP connection through a tunnel is a good hint
+that none is.  But the monitoring is complex, and it doesn't seem worth
+the trouble. 
+
+IKE connections likewise should be torn down when it appears the need has
+passed.  They should linger longer than the last tunnel they administer,
+just in case they are needed again; the cost of retaining them is low.  An
+SG with only a modest number of them open might want to simply retain each
+until rekeying time, with more aggressive management cutting in only when
+the number gets large.  (They should be torn down eventually, if only to
+minimize the length of a status report, but rekeying is the only expensive
+event for them.)
+
+It's worth remembering that tunnels sometimes go down because the other
+end crashes, or disconnects, or has a network link break, and we don't get
+any notice of this in the general case.  (Even in the event of a crash and
+successful reboot, we won't hear about it unless the other end has
+specific reason to talk IKE to us immediately.)  Of course, we have to
+guard against being too quick to respond to temporary network outages,
+but it's not quite the same issue for us as for TCP, because we can tear
+down and then re-establish a tunnel without any user-visible effect except
+a pause in traffic.  And if the other end does go down and come back up,
+we and it can't communicate *at all* (except via IKE) until we tear down
+our tunnel.
+
+So... we need some kind of heartbeat mechanism.  Currently there is none
+in IKE, but there is discussion of changing that, and this seems like the
+best approach.  Doing a heartbeat at the IP level will not tell us about a
+crash/reboot event, and sending heartbeat packets through tunnels has
+various complications (they should stop at the far mouth of the tunnel
+instead of going on to a subnet; they should not count against idle
+timers; etc.).  Heartbeat exchanges obviously should be done only when
+there are tunnels established *and* there has been no recent incoming
+traffic through them.  It seems reasonable to do them at lifespan ends,
+subject to appropriate rate limiting when more than one tunnel goes to the
+same other SG.  When all traffic between the two ends is supposed to go
+via the tunnel, it might be reasonable to do a heartbeat -- subject to a
+rate limiter to avoid DOS attacks -- if the kernel sees a non-tunnel
+non-IKE packet from the other end. 
+
+If a heartbeat gets no response, try a few (say 3) pings to check IP
+connectivity; if one comes back, try another heartbeat; if it gets no
+response, the other end has rebooted, or otherwise been re-initialized,
+and its tunnels should be torn down.  If there's no response to the pings,
+note the fact and try the sequence again at the next lifespan end; if
+there's nothing then either, declare the tunnels dead. 
+
+Finally... except in cases where we've decided that the other end is dead
+or has rebooted, tunnel teardown should always be coordinated with the
+other end.  This means interpreting and sending Delete notifications, and
+also Initial-Contacts.  Receiving a Delete for the other party's tunnel
+SAs should lead us to tear down our end too -- SAs (SA bundles, really)
+need to be considered as paired bidirectional entities, even though the
+low-level protocols don't think of them that way. 
+
+
+
+SGD, AWP
+
+Given a packet destination, how do we decide who to (attempt to) negotiate
+a tunnel with?  And as a related issue, how do the negotiating parties
+authenticate each other?  DNSSEC obviously provides the tools for the
+latter, but how exactly do we use them?
+
+Having intercepted a packet, what we know is basically the IP addresses of
+source and destination (plus, in principle, some information about the
+desired communication, like protocol and port).  We might be able to map
+the source address to more information about the source, depending on how
+well we control our local networks, but we know nothing further about the
+destination. 
+
+The obvious first thing to do is a DNS reverse lookup on the destination
+address; that's about all we can do with available data.  Ideally, we'd
+like to get all necessary information with this one DNS lookup, because
+DNS lookups are time-consuming -- all the more so if they involve a DNSSEC
+signature-checking treewalk by the name server -- and we've got to hurry.
+While it is unusual for a reverse lookup to yield records other than PTR
+records (or possibly CNAME records, for RFC 2317 classless delegation),
+there's no reason why it can't.
+
+(For purposes like logging, a reverse lookup is usually followed by a
+forward lookup, to verify that the reverse lookup wasn't lying about the
+host name.  For our purposes, this is not vital, since we use stronger
+authentication methods anyway.)
+
+While we want to get as much data as possible (ideally all of it) from one
+lookup, it is useful to first consider how the necessary information would
+be obtained if DNS lookups were instantaneous.  Two pieces of information
+are absolutely vital at this point:  the IP address of the other end's
+security gateway, and the SG's public key*. 
+
+(* Actually, knowledge of the key can be postponed slightly -- it's not
+needed until the second exchange of the negotiations, while we can't even
+start negotiations without knowing the IP address.  The SG is not
+necessarily on the plain-IP route to the destination, especially when
+multiple SGs are present.)
+
+Given instantaneous DNS lookups, we would:
+
++ Start with a reverse lookup to turn the address into a name.
+
++ Look for something like RFC-2782 SRV records using the name, to find out
+who provides this particular service.  If none comes back, we can abandon
+the whole process. 
+
++ Select one SRV record, which gives us the name of a target host (plus
+possibly one or more addresses, if the name server has supplied address
+records as Additional Data for the SRV records -- this is recommended
+behavior but is not required). 
+
++ Use the target name to look up a suitable KEY record, and also address
+record(s) if they are still needed. 
+
+This gives us the desired address(es) and key.  However, it requires three
+lookups, and we don't even find out whether there's any point in trying
+until after the second.
+
+With real DNS lookups, which are far from instantaneous, some optimization
+is needed.  At the very least, typical cases should need fewer lookups.
+
+So when we do the reverse lookup on the IP address, instead of asking for
+PTR, we ask for TXT.  If we get none, we abandon opportunistic
+negotiation, and set up a bypass/block with a relatively long life (say
+6hr) because it's not worth trying again soon.  (Note, there needs to be a
+way to manually force an early retry -- say, by just clearing out all
+memory of a particular address -- to cover cases where a configuration
+error is discovered and fixed.)
+
+xxx need to discuss multi-string TXTs
+
+In the results, we look for at least one TXT record with content
+"X-IPsec-Server(nnn)=a.b.c.d kkk", following RFC 1464 attribute/value
+notation.  (The "X-" indicates that this is tentative and experimental;
+this design will probably need modification after initial experiments.)
+Again, if there is no such record, we abandon opportunistic negotiation. 
+
+"nnn" and the parentheses surrounding it are optional.  If present, it
+specifies a priority (low number high priority), as for MX records, to
+control the order in which multiple servers are tried.  If there are no
+priorities, or there are ties, pick one randomly.
+
+"a.b.c.d" is the dotted-decimal IP address of the SG.  (Suitable extensions
+for IPv6, when the time comes, are straightforward.)
+
+"kkk" is either an RSA-MD5 public key in base-64 notation, as in the text
+form of an RFC 2535 KEY record, or "@hhh".  In the latter case, hhh is a
+DNS name, under which one Host/Authentication/IPSEC/RSA-MD5 KEY record is
+present, giving the server's authentication key.  (The delay of the extra
+lookup is undesirable, but practical issues of key management may make it
+advisable not to duplicate the key itself in DNS entries for many
+clients.)
+
+It unfortunately does appear that the authentication key has to be
+associated with the server, not the client behind it.  At the time when
+the responder has to authenticate our SG, it does not know which of its
+clients we are interested in (i.e., which key to use), and there is no
+good way to tell it.  (There are some bad ways; this decision may merit
+re-examination after experimental use.)
+
+The responder authenticates our SG by doing a reverse lookup on its IP
+address to get a Host/Authentication/IPSEC/RSA-MD5 KEY record.  He can
+attempt this in parallel with the early parts of the negotiation (since he
+knows our SG IP address from the first negotiation packet), at the risk of
+having to abandon the attempt and do a different lookup if we use
+something different as our ID (see below).  Unfortunately, he doesn't yet
+know what client we will claim to represent, so he'll need to do another
+lookup as part of phase 2 negotiation (unless the client *is* our SG), to
+confirm that the client has a TXT X-IPsec-Server record pointing to our
+SG.  (Checking that the record specifies the same key is not important,
+since the responder already has a trustworthy key for our SG.)
+
+Also unfortunately, opportunistic tunnels can only have degenerate subnets
+(/32 subnets, containing one host) at their ends.  It's superficially
+attractive to negotiate broader connections... but without prearrangement,
+you don't know whether you can trust the other end's claim to have a
+specific subnet behind it.  Fixing this would require a way to do a
+reverse lookup on the *subnet* (you cannot trust information in DNS
+records for a name or a single address, which may be controlled by people
+who do not control the whole subnet) with both the address and the mask
+included in the name.  Except in the special case of a subnet masked on a
+byte boundary (in which case RFC 1035's convention of an incomplete
+in-addr.arpa name could be used), this would need extensions to the
+reverse-map name space, which is awkward, especially in the presence of
+RFC 2317 delegation.  (IPv6 delegation is more flexible and it might be
+easier there.)
+
+There is a question of what ID should be used in later steps of
+negotiation.  However, the desire not to put more DNS lookups in the
+critical path suggests avoiding the extra complication of varied IDs,
+except in the Road Warrior case (where an extra lookup is inevitable).
+Also, figuring out what such IDs *mean* gets messy.  To keep things simple,
+except in the RW case, all IDs should be IP addresses identical to those
+used in the packet headers.
+
+For Road Warrior, the RW must be the initiator, since the home-base SG has
+no idea what address the RW will appear at.  Moreover, in general the RW
+does not control the DNS entries for his address.  This inherently denies
+the home base any authentication of the RW's IP address; the most it can
+do is to verify an identity he provides, and perhaps decide whether it
+wishes to talk to someone with that identity, but this does not verify his
+right to use that IP address -- nothing can, really. 
+
+(That may sound like it would permit some man-in-the-middle attacks, but
+the RW can still do full authentication of the home base, so a man in the
+middle cannot successfully impersonate home base.  Furthermore, a man in
+the middle must impersonate both sides for the DH exchange to work.  So
+either way, the IKE negotiation falls apart.)
+
+A Road Warrior provides an FQDN ID, used for a forward lookup to obtain a
+Host/Authentication/IPSEC/RSA-MD5 KEY record.  (Note, an FQDN need not
+actually correspond to a host -- e.g., the DNS data for it need not
+include an A record.)  This suffices, since the RW is the initiator and
+the responder knows his address from his first packet.
+
+Certain situations where a host has a more-or-less permanent IP address,
+but does not control its DNS entries, must be treated essentially like
+Road Warrior.  It is unfortunate that DNS's old inverse-query feature
+cannot be used (nonrecursively) to ask the initiator's local DNS server
+whether it has a name for the address, because the address will almost
+always have been obtained from a DNS name lookup, and it might be a lookup
+of a name whose DNS entries the host *does* control.  (Real examples of
+this exist:  the host has a preferred name whose host-controlled entry
+includes an A record, but a reverse lookup on the address sends you to an
+ISP-controlled name whose entry has an A record but not much else.)  Alas,
+inverse query is long obsolete and is not widely implemented now. 
+
+There are some questions in failure cases.  If we cannot acquire the info
+needed to set up a tunnel, this is the no-tunnel-possible case.  If we
+reach an SG but negotiation fails, this too is the no-tunnel-possible
+case, with a relatively long bypass/block lifespan (say 1hr) since
+fruitless negotiations are expensive.  (In the multiple-SG case, it seems
+unlikely to be worthwhile to try other SGs just in case one of them might
+have a configuration permitting successful negotiation.)
+
+Finally, there is a sticky problem with timeouts.  If the other SG is down
+or otherwise inaccessible, in the worst case we won't hear about this
+except by not getting responses.  Some other, more pathological or even
+evil, failure cases can have the same result.  The problem is that in the
+case where a bypass is permitted, we want to decide whether a tunnel is
+possible quickly.  It gets even worse if there are multiple SGs, in which
+case conceivably we might want to try them all (since some SGs being up
+when others are down is much more likely than SGs differing in policy). 
+
+The patience setting needs to be configurable policy, with a reasonable
+default (to be determined by experiment).  If it expires, we simply have
+to declare the attempt a failure, and set up a bypass/block.  (Setting up
+a tentative bypass/block, and replacing it with a real tunnel if remaining
+attempts do produce one, looks attractive at first glance... but exposing
+the first few seconds of a connection is often almost as bad as exposing
+the whole thing!)  Such a bypass/block should have a short lifespan, say
+10min, because the SG(s) might be only temporarily unavailable.
+
+The flip side of IKE waiting for a timeout is that all other forms of
+feedback, e.g. "host not reachable", should be *ignored*, because you
+cannot trust them!  This may need kernel changes. 
+
+Can AWP be done by non-opportunistic SGs?  Probably not; existing SG
+implementations generally aren't prepared to do anything suitable, except
+perhaps via the messy business of certificates.  There is one borderline
+exception:  some implementations rely on LDAP for at least some of their
+information fetching, and it might be possible to substitute a custom LDAP
+server which does the right things for them.  Feasibility of this depends
+on details, which we don't know well enough. 
+
+[This could do with a full example, a complete packet by packet walkthrough
+including all DNS and IKE traffic.]
+
+
+
+MFP
+
+Our current conn database simply isn't flexible enough to cover all this
+properly.  In particular, the responding Pluto needs a way to figure out
+whether the connection it is being asked to make is legitimate.
+
+This is more subtle than it sounds, given the problem noted earlier, that
+there's no clear way to authenticate claims to represent a non-degenerate
+subnet.  Our database has to be able to say "a connection to any host in
+this subnet is okay" or "a connection to any subnet within this subnet is
+okay", rather than "a connection to exactly this subnet is okay".  (There
+is some analogy to the Road Warrior case here, which may be relevant.)
+This will require at least a re-interpretation of ipsec.conf.
+
+Interim stages of implementation of this will require a bit of thought.
+Notably, we need some way of dealing with the lack of fully signed DNSSEC
+records.  Without user interaction, probably the best we can do is to
+remember the results of old fetches, compare them to the results of new
+fetches, and complain and disbelieve all of it if there's a mismatch. 
+This does mean that somebody who gets fake data into our very first fetch
+will fool us, at least for a while, but that seems an acceptable tradeoff.
+
+
+
+Negotiation Issues
+
+There are various options which are nominally open to negotiation as part
+of setup, but which have to be nailed down at least well enough that
+opportunistic SGs can reliably interoperate.  Somewhat arbitrarily and
+tentatively, opportunistic SGs must support Main Mode, Oakley group 5 for
+D-H, 3DES encryption and MD5 authentication for both ISAKMP and IPsec SAs,
+RSA digital-signature authentication with keys between 2048 and 8192 bits,
+and ESP doing both encryption and authentication.  They must do key PFS
+in Quick Mode, but not identity PFS.
+
+
+
+What we need from DNS
+
+Fortunately, we don't need any new record types or suchlike to make this
+all work.  We do, however, need attention to a couple of areas in DNS
+implementation.
+
+First, size limits.  Although the information we directly need from a
+lookup is not enormous -- the only potentially-big item is the KEY record,
+and there should be only one of those -- there is still a problem with
+DNSSEC authentication signatures.  With a 2048-bit key and assorted
+supporting information, we will fill most of a 512-byte DNS UDP packet...
+and if the data is to have DNSSEC authentication, at least one quite large
+SIG record will come too.  Plus maybe a TSIG signature on the whole
+response, to authenticate it to our resolver.  So:  DNSSEC-capable name
+servers must fix the 512-byte UDP limit.  We're told there are provisions
+for this; implementation of them is mandatory. 
+
+Second, interface.  It is unclear how the resolver interface will let us
+ask for DNSSEC authentication.  We would prefer to ask for "authentication
+where possible", and get back the data with each item flagged by whether
+authentication was available (and successful!) or not available.  Having
+to ask separately for authenticated and non-authenticated data would
+probably be acceptable, *provided* both will be cached on the first
+request, so the two requests incur only one set of (non-local) network
+traffic.  Either way, we want to see the name server and resolver do this
+for us; that makes sense in any case, since it's important that
+verification be done somewhere where it can be cached, the more centrally
+the better. 
+
+Finally, a wistful note:  the ability to do a limited form of inverse
+queries (an almost forgotten feature), to ask the local name server which
+hostname it recently mapped to a particular address, would be quite
+helpful.  Note, this is *NOT* the same as a reverse lookup, and crude
+fakes like putting a dotted-decimal address in brackets do not suffice. 
diff --git a/doc/opportunism-spec.txt b/doc/opportunism-spec.txt
new file mode 100644
index 000000000..fbe319a57
--- /dev/null
+++ b/doc/opportunism-spec.txt
@@ -0,0 +1,1254 @@
+
+
+
+
+
+
+
+
+
+                  Opportunistic Encryption
+
+                       Henry Spencer
+                     D. Hugh Redelmeier
+                    henry@spsystems.net
+                      hugh@mimosa.com
+                  Linux FreeS/WAN Project
+
+
+
+          Opportunistic   encryption   permits   secure
+     (encrypted, authenticated) communication via IPsec
+     without  connection-by-connection  prearrangement,
+     either explicitly between hosts  (when  the  hosts
+     are  capable  of  it) or transparently via packet-
+     intercepting  security  gateways.   It  uses   DNS
+     records (authenticated with DNSSEC) to provide the
+     necessary information for  gateway  discovery  and
+     gateway authentication, and constrains negotiation
+     enough to guarantee success.
+
+     Substantive  changes  since  draft  3:  write  off
+     inverse  queries  as a lost cause; use Invalid-SPI
+     rather than Delete as notification of unknown  SA;
+     minor  wording  improvements  and  clarifications.
+     This document takes over from the  older  ``Imple-
+     menting Opportunistic Encryption'' document.
+
+
+1.  Introduction
+
+A  major  goal  of  the  FreeS/WAN  project is opportunistic
+encryption: a  (security)  gateway  intercepts  an  outgoing
+packet aimed at a remote host, and quickly attempts to nego-
+tiate an IPsec tunnel to that host's security  gateway.   If
+the  attempt succeeds, traffic can then be secure, transpar-
+ently (without  changes  to  the  host  software).   If  the
+attempt  fails,  the  packet  (or  a  retry  thereof) passes
+through in clear or is dropped, depending on  local  policy.
+Prearranged  tunnels bypass the packet interception etc., so
+static VPNs can coexist with opportunistic encryption.
+
+This generalizes trivially to the end-to-end case: host  and
+security  gateway  simply  are one and the same.  Some opti-
+mizations are possible in that case, but  the  basic  scheme
+need not change.
+
+The  objectives  for  security systems need to be explicitly
+stated.  Opportunistic encryption is meant to achieve secure
+communication, without prearrangement of the individual con-
+nection (although some prearrangement on a per-host basis is
+
+
+
+Draft 4                  3 May 2001                        1
+
+
+
+
+
+                  Opportunistic Encryption
+
+
+required),  between any two hosts which implement the proto-
+col (and, if they act as security  gateways,  between  hosts
+behind  them).   Here ``secure'' means strong encryption and
+authentication of packets, with authentication  of  partici-
+pants--to   prevent   man-in-the-middle   and  impersonation
+attacks--dependent on several factors.  The  biggest  factor
+is  the authentication of DNS records, via DNSSEC or equiva-
+lent means.  A lesser factor is which exact variant  of  the
+setup  procedure (see section 2.2) is used, because there is
+a tradeoff between strong authentication of  the  other  end
+and ability to negotiate opportunistic encryption with hosts
+which have limited or no control of  their  reverse-map  DNS
+records: without reverse-map information, we can verify that
+the host has the right to use a particular FQDN (Fully Qual-
+ified  Domain Name), but not whether that FQDN is authorized
+to use that IP address.  Local policy  must  decide  whether
+authentication or connectivity has higher priority.
+
+Apart  from  careful  attention  to detail in various areas,
+there are three crucial design  problems  for  opportunistic
+encryption.   It  needs a way to quickly identify the remote
+host's security gateway.  It needs a way to  quickly  obtain
+an  authentication  key  for  the security gateway.  And the
+numerous options which can be specified  with  IKE  must  be
+constrained  sufficiently  that  two independent implementa-
+tions  are  guaranteed  to  reach  agreement,  without   any
+explicit  prearrangement  or  preliminary  negotiation.  The
+first two problems are solved using DNS, with DNSSEC  ensur-
+ing  that the data obtained is reliable; the third is solved
+by specifying a minimum standard which must be supported.
+
+A note on philosophy: we have deliberately avoided providing
+six  different  ways  to do each job, in favor of specifying
+one good one.  Choices are provided only when they appear to
+be necessary, or at least important.
+
+A note on terminology: to avoid constant circumlocutions, an
+ISAKMP/IKE SA, possibly recreated occasionally by  rekeying,
+will  be  referred  to as a ``keying channel'', and a set of
+IPsec SAs providing bidirectional communication between  two
+IPsec  hosts,  possibly  recreated occasionally by rekeying,
+will be referred to as a ``tunnel''  (it  could  conceivably
+use transport mode in the host-to-host case, but we advocate
+using tunnel mode even there).  The word  ``connection''  is
+here  used  in  a more generic sense.  The word ``lifetime''
+will be avoided in favor  of  ``rekeying  interval'',  since
+many  of  the connections will have useful lives far shorter
+than any reasonable rekeying interval,  and  hence  the  two
+concepts must be separated.
+
+A note on document structure: Discussions of why things were
+done a particular way, or not done  a  particular  way,  are
+broken  out in paragraphs headed ``Rationale:'' (to preserve
+the flow of the text, many such paragraphs are  deferred  to
+
+
+
+Draft 4                  3 May 2001                        2
+
+
+
+
+
+                  Opportunistic Encryption
+
+
+the ends of sections).  Paragraphs headed ``Ahem:'' are dis-
+cussions of where the problem is  being  made  significantly
+harder  by  problems  elsewhere,  and how that might be cor-
+rected.  Some meta-comments are enclosed in [].
+
+Rationale: The motive is  to  get  the  Internet  encrypted.
+That  requires  encryption  without connection-by-connection
+prearrangement: a system must be able to reliably  negotiate
+an   encrypted,   authenticated   connection  with  a  total
+stranger.  While end-to-end encryption is preferable,  doing
+opportunistic encryption in security gateways gives enormous
+leverage for quick deployment of this technology, in a world
+where  end-host software is often primitive, rigid, and out-
+dated.
+
+Rationale: Speed is of the essence in tunnel setup:  a  con-
+nection-establishment  delay  longer  than  about 10 seconds
+begins to cause problems for users and  applications.   Thus
+the emphasis on rapidity in gateway discovery and key fetch-
+ing.
+
+Ahem: Host-to-host opportunistic encryption would be utterly
+trivial  if a fast public-key encryption/signature algorithm
+was available.  You would do a reverse lookup on the  desti-
+nation  address to obtain a public key for that address, and
+simply encrypt all packets going to it with that key,  sign-
+ing them with your own private key.  Alas, this is impracti-
+cal with current CPU speeds and current algorithms (although
+as  noted  later,  it  might be of some use for limited pur-
+poses).  Nevertheless, it is a useful model.
+
+2.  Connection Setup
+
+For purposes of discussion, the network  is  taken  to  look
+like this:
+
+     Source----Initiator----...----Responder----Destination
+
+The  intercepted packet comes from the Source, bound for the
+Destination, and is intercepted at the Initiator.  The  Ini-
+tiator  communicates  over  the  insecure  Internet  to  the
+Responder.  The Source and the Initiator might be  the  same
+host,  or  the Source might be an end-user host and the Ini-
+tiator a security gateway (SG).  Likewise for the  Responder
+and the Destination.
+
+Given  an  intercepted packet, whose useful information (for
+our purposes)  is  essentially  only  the  Destination's  IP
+address,  the Initiator must quickly determine the Responder
+(the  Destination's  SG)  and  fetch  everything  needed  to
+authenticate  it.   The  Responder  must do likewise for the
+Initiator.  Both must eventually also confirm that the other
+is  authorized to act on behalf of the client host behind it
+(if any).
+
+
+
+Draft 4                  3 May 2001                        3
+
+
+
+
+
+                  Opportunistic Encryption
+
+
+An important subtlety here is that if the alternative to  an
+IPsec  tunnel  is  plaintext  transmission, negative results
+must be obtained quickly.  That is,  the  decision  that  no
+tunnel can be established must also be made rapidly.
+
+2.1.  Packet Interception
+
+Interception  of outgoing packets is relatively straightfor-
+ward in principle.  It is preferable to put the  intercepted
+packet  on  hold rather than dropping it, since higher-level
+retries are not necessarily well-timed.  There is a  problem
+of hosts and applications retrying during negotiations.  ARP
+implementations,  which  face  the  same  problem,  use  the
+approach  of  keeping  the most recent packet for an as-yet-
+unresolved address, and throwing away older  ones.   (Incre-
+menting  of request numbers etc. means that replies to older
+ones may no longer be accepted.)
+
+Is it worth intercepting incoming packets, from the  outside
+world,  and  attempting  tunnel  setup  based  on them?  No,
+unless and until a way can be  devised  to  initiate  oppor-
+tunistic   encryption   to  a  non-opportunistic  responder,
+because if the other end  has  not  initiated  tunnel  setup
+itself, it will not be prepared to do so at our request.
+
+Rationale:  Note,  however,  that most incoming packets will
+promptly be followed by  an  outgoing  packet  in  response!
+Conceivably  it  might  be  useful  to start early stages of
+negotiation, at least as far as looking up  information,  in
+response to an incoming packet.
+
+Rationale: If a plaintext incoming packet indicates that the
+other end is not prepared to do opportunistic encryption, it
+might  seem that this fact should be noted, to avoid consum-
+ing resources and delaying traffic in an attempt  at  oppor-
+tunistic setup which is doomed to fail.  However, this would
+be a major security hole, since the plaintext packet is  not
+authenticated; see section 2.5.
+
+2.2.  Algorithm
+
+For  clarity,  the following defers most discussion of error
+handling to the end.
+
+Step 1.  Initiator does a DNS reverse lookup on the Destina-
+         tion address, asking not for the usual PTR records,
+         but for TXT  records.   Meanwhile,  Initiator  also
+         sends a ping to the Destination, to cause any other
+         dynamic setup actions to  start  happening.   (Ping
+         replies  are  disregarded;  the  host  might not be
+         reachable with plaintext pings.)
+
+Step 2A. If at least one suitable TXT  record  (see  section
+         2.3)   comes   back,   each  contains  a  potential
+
+
+
+Draft 4                  3 May 2001                        4
+
+
+
+
+
+                  Opportunistic Encryption
+
+
+         Responder's IP address and that Responder's  public
+         key (or where to find it).  Initiator picks one TXT
+         record, based on priority (see 2.3), thus picking a
+         Responder.   If  there was no public key in the TXT
+         record, the Initiator also starts a DNS lookup  (as
+         specified by the TXT record) to get KEY records.
+
+Step 2B. If  no suitable TXT record is available, and policy
+         permits,  Initiator  designates   the   Destination
+         itself as the Responder (see section 2.4).  If pol-
+         icy does not permit, or the  Destination  is  unre-
+         sponsive  to  the  negotiation,  then opportunistic
+         encryption is not possible, and Initiator gives  up
+         (see section 2.5).
+
+Step 3.  If there already is a keying channel to the Respon-
+         der's IP address, the Initiator uses  the  existing
+         keying  channel;  skip  to step 10.  Otherwise, the
+         Initiator starts an IKE Phase  1  negotiation  (see
+         section  2.7  for details) with the Responder.  The
+         address family of the Responder's IP  address  dic-
+         tates whether the keying channel and the outside of
+         the tunnel should be IPv4 or IPv6.
+
+Step 4.  Responder gets the first IKE message, and responds.
+         It  also starts a DNS reverse lookup on the Initia-
+         tor's IP address, for KEY records, on  speculation.
+
+Step 5.  Initiator  gets  Responder's reply, and sends first
+         message of IKE's D-H exchange (see 2.4).
+
+Step 6.  Responder  gets  Initiator's   D-H   message,   and
+         responds with a matching one.
+
+Step 7.  Initiator  gets Responder's D-H message; encryption
+         is now established, authentication  remains  to  be
+         done.   Initiator sends IKE authentication message,
+         with an FQDN identity if a reverse  lookup  on  its
+         address  will  not  yield  a  suitable  KEY record.
+         (Note, an FQDN need not actually  correspond  to  a
+         host--e.g., the DNS data for it need not include an
+         A record.)
+
+Step 8.  Responder gets Initiator's authentication  message.
+         If  there  is no identity included, Responder waits
+         for step 4's speculative DNS lookup to  finish;  it
+         should  yield  a suitable KEY record (see 2.3).  If
+         there is an FQDN identity, responder  discards  any
+         data obtained from step 4's DNS lookup; does a for-
+         ward lookup on the FQDN, for a  KEY  record;  waits
+         for  that lookup to return; it should yield a suit-
+         able KEY record.  Either way,  Responder  uses  the
+         KEY  data  to verify the message's hash.  Responder
+         replies with an  authentication  message,  with  an
+
+
+
+Draft 4                  3 May 2001                        5
+
+
+
+
+
+                  Opportunistic Encryption
+
+
+         FQDN  identity  if  a reverse lookup on its address
+         will not yield a suitable KEY record.
+
+Step 9A. (If step 2A was  used.)   The  Initiator  gets  the
+         Responder's  authentication  message.   Step 2A has
+         provided a key (from the  TXT  record  or  via  DNS
+         lookup).   Verify  message's  hash.   Encrypted and
+         authenticated keying channel  established,  man-in-
+         middle attack precluded.
+
+Step 9B. (If  step  2B  was  used.)   The Initiator gets the
+         Responder's authentication message, which must con-
+         tain an FQDN identity (if the Responder can't put a
+         TXT in his reverse map he presumably can't do a KEY
+         either).   Do forward lookup on the FQDN, get suit-
+         able KEY record,  verify  hash.   Encrypted  keying
+         channel   established,  man-in-middle  attack  pre-
+         cluded, but authentication weak (see 2.4).
+
+Step 10. Initiator initiates IKE Phase  2  negotiation  (see
+         2.7)  to  establish  tunnel,  specifying Source and
+         Destination identities as IP addresses  (see  2.6).
+         The  address  family of those addresses also deter-
+         mines whether the inside of the  tunnel  should  be
+         IPv4 or IPv6.
+
+Step 11. Responder  gets  first  Phase  2  message.  Now the
+         Responder finally knows what's  going  on!   Unless
+         the specified Source is identical to the Initiator,
+         Responder initiates DNS reverse lookup on Source IP
+         address,  for  TXT  records; waits for result; gets
+         suitable TXT record(s) (see 2.3), which should con-
+         tain  either  the Initiator's IP address or an FQDN
+         identity identical to that supplied by the  Initia-
+         tor in step 7.  This verifies that the Initiator is
+         authorized to act as SG for the Source.   Responder
+         replies  with  second  Phase  2  message, selecting
+         acceptable details (see 2.7), and establishes  tun-
+         nel.
+
+Step 12. Initiator  gets second Phase 2 message, establishes
+         tunnel (if he didn't  already),  and  releases  the
+         intercepted packet into it, finally.
+
+Step 13. Communication  proceeds.   See  section  3 for what
+         happens later.
+
+As additional  information  becomes  available,  notably  in
+steps 1, 2, 4, 8, 9, 11, and 12, there is always a possibil-
+ity that local policy (e.g., access limitations) might  pre-
+vent  further progress.  Whenever possible, at least attempt
+to inform the other end of this.
+
+
+
+
+
+Draft 4                  3 May 2001                        6
+
+
+
+
+
+                  Opportunistic Encryption
+
+
+At any time, there is a possibility of the negotiation fail-
+ing  due  to  unexpected  responses,  e.g. the Responder not
+responding at all or rejecting  all  Initiator's  proposals.
+If  multiple SGs were found as possible Responders, the Ini-
+tiator should try at least one more before giving  up.   The
+number  tried  should  be influenced by what the alternative
+is: if the traffic will otherwise be discarded,  trying  the
+full  list is probably appropriate, while if the alternative
+is plaintext transmission, it might be based on how long the
+tries  are  taking.   The Initiator should try as many as it
+reasonably can, ideally all of them.
+
+There is a sticky problem with timeouts.  If  the  Responder
+is  down  or  otherwise  inaccessible,  in the worst case we
+won't hear about this except by not getting responses.  Some
+other,  more  pathological  or  even evil, failure cases can
+have the same result.  The problem is that in the case where
+plaintext  is  permitted, we want to decide whether a tunnel
+is possible quickly.  There is no  good  solution  to  this,
+alas; we just have to take the time and do it right.  (Pass-
+ing plaintext meanwhile looks attractive at first  glance...
+but  exposing the first few seconds of a connection is often
+almost as bad as exposing the whole thing.   Worse,  if  the
+user  checks  the status of the connection, after that brief
+window it looks secure!)
+
+The flip side of waiting for a timeout  is  that  all  other
+forms  of  feedback,  e.g.  ``host not reachable'', arguably
+should be ignored, because in the absence  of  authenticated
+ICMP, you cannot trust them!
+
+Rationale:  An  alternative, sometimes suggested, to the use
+of explicit DNS records for  SG  discovery  is  to  directly
+attempt  IKE  negotiation  with  the  destination  host, and
+assume that any relevant SG will be on the packet path, will
+intercept the IKE packets, and will impersonate the destina-
+tion host for the IKE negotiation.   This  is  superficially
+attractive  but is a very bad idea.  It assumes that routing
+is stable throughout negotiation, that  the  SG  is  on  the
+plaintext-packets  path,  and  that  the destination host is
+routable (yes, it is possible to have (private) DNS data for
+an  unroutable host).  Playing extra games in the plaintext-
+packet path hurts performance and  can  be  expected  to  be
+unpopular.  Various difficulties ensue when there are multi-
+ple SGs along the path (there is already bad experience with
+this,  in  RSVP),  and  the presence of even one can make it
+impossible to do IKE direct to the host when that is  what's
+wanted.  Worst of all, such impersonation breaks the IP net-
+work model badly, making problems difficult to diagnose  and
+impossible  to work around (and there is already bad experi-
+ence with this, in areas like web caching).
+
+Rationale: (Step 1.)  Dynamic setup  actions  might  include
+establishment   of  demand-dialed  links.   These  might  be
+
+
+
+Draft 4                  3 May 2001                        7
+
+
+
+
+
+                  Opportunistic Encryption
+
+
+present anywhere along the path, so one cannot rely on  out-
+of-band  communication  at  the  Initiator  to trigger them.
+Hence the ping.
+
+Rationale: (Step 2.)  In many cases, the IP address  on  the
+intercepted  packet will be the result of a name lookup just
+done.  Inverse queries, an obscure DNS feature from the dis-
+tant  past,  in  theory  can  be used to ask a DNS server to
+reverse that lookup,  giving  the  name  that  produced  the
+address.   This is not the same as a reverse lookup, and the
+difference can matter a great deal in  cases  where  a  host
+does  not  control its reverse map (e.g., when the host's IP
+address is dynamically  assigned).   Unfortunately,  inverse
+queries were never widely implemented and are now considered
+obsolete.  Phooey.
+
+Ahem: Support for a small subset of this  admittedly-obscure
+feature  would be useful.  Unfortunately, it seems unlikely.
+
+Rationale: (Step 3.)  Using  only  IP  addresses  to  decide
+whether  there  is  already a relevant keying channel avoids
+some difficult problems.  In particular, it might seem  that
+this  should be based on identities, but those are not known
+until very late in IKE Phase 1 negotiations.
+
+Rationale: (Step 4.)  The DNS lookup is done on  speculation
+because  the data will probably be useful and the lookup can
+be done in parallel with IKE activity, potentially  speeding
+things up.
+
+Rationale:  (Steps  7 and 8.)  If an SG does not control its
+reverse map, there is no way it can prove its right  to  use
+an  IP address, but it can nevertheless supply both an iden-
+tity (as an FQDN) and proof of its right to use  that  iden-
+tity.   This  is  somewhat  better  than nothing, and may be
+quite useful if the SG is representing a client  host  which
+can  prove  its  right  to  its IP address.  (For example, a
+fixed-address subnet might live behind an SG with a  dynami-
+cally-assigned  address; such an SG has to be the Initiator,
+not the Responder, so the subnet's TXT records  can  contain
+FQDN identities, but with that restriction, this works.)  It
+might sound like this would  permit  some  man-in-the-middle
+attacks in important cases like Road Warrior, but the RW can
+still do full authentication of the home base, so a  man  in
+the  middle  cannot  successfully impersonate home base, and
+the D-H exchange doesn't work unless the man in  the  middle
+impersonates both ends.
+
+Rationale:  (Steps  7 and 8.)  Another situation where proof
+of the right to use an identity can be very useful  is  when
+access is deliberately limited.  While opportunistic encryp-
+tion is intended as a general-purpose  connection  mechanism
+between strangers, it may well be convenient for prearranged
+connections to use the same mechanism.
+
+
+
+Draft 4                  3 May 2001                        8
+
+
+
+
+
+                  Opportunistic Encryption
+
+
+Rationale: (Steps 7 and 8.)  FQDNs as identities are avoided
+where  possible,  since  they  can  involve  synchronous DNS
+lookups.
+
+Rationale: (Step 11.)  Note that only here, in Phase 2, does
+the  Responder actually learn who the Source and Destination
+hosts are.  This unfortunately  demands  a  synchronous  DNS
+lookup  to verify that the Initiator is authorized to repre-
+sent the Source, unless they are one and the same.  This and
+the  initial TXT lookup are the only synchronous DNS lookups
+absolutely required by the algorithm, and they appear to  be
+unavoidable.
+
+Rationale:  While  it  might seem unlikely that a refusal to
+cooperate from one SG could be remedied by trying  another--
+presumably  they all use the same policies--it's conceivable
+that one might be misconfigured.  Preferably they should all
+be tried, but it may be necessary to set some limits on this
+if alternatives exist.
+
+2.3.  DNS Records
+
+Gateway discovery and key lookup are based on  TXT  and  KEY
+DNS  records.   The TXT record specifies IP address or other
+identity of a host's SG, and possibly  supplies  its  public
+key  as  well, while the KEY record supplies public keys not
+found in TXT records.
+
+2.3.1.  TXT
+
+Opportunistic-encryption SG discovery uses TXT records  with
+the content:
+
+     X-IPsec-Gateway(nnn)=iii kkk
+
+following  RFC 1464 attribute/value notation.  Records which
+do not contain an ``='', or which do not  have  exactly  the
+specified form to the left of it, are ignored.  (Near misses
+perhaps should be reported.)
+
+The nnn is an unsigned integer which will fit  in  16  bits,
+specifying  an  MX-style preference (lower number = stronger
+preference) to control the order in which multiple  SGs  are
+tried.   If  there  are ties, pick one, randomly enough that
+the choice will probably be different each time.  The  pref-
+erence field is not optional; use ``0'' if there is no mean-
+ingful preference ordering.
+
+The iii part identifies the SG.  Normally this is a  dotted-
+decimal  IPv4 address or a colon-hex IPv6 address.  The sole
+exception is if the SG has no fixed address  (see  2.4)  but
+the  host(s)  behind it do, in which case iii is of the form
+``@fqdn'', where fqdn is the FQDN that the SG  will  use  to
+identify  itself  (in  step 7 of section 2.2); such a record
+
+
+
+Draft 4                  3 May 2001                        9
+
+
+
+
+
+                  Opportunistic Encryption
+
+
+cannot be used for SG discovery by an Initiator, but can  be
+used for SG verification (step 11 of 2.2) by a Responder.
+
+The  kkk  part is optional.  If it is present, it is an RSA-
+MD5 public key in base-64 notation, as in the text  form  of
+an  RFC  2535 KEY record.  If it is not present, this speci-
+fies that the public key  can  be  found  in  a  KEY  record
+located  based  on  the SG's identification: if iii is an IP
+address, do a reverse lookup on that address, else do a for-
+ward lookup on the FQDN.
+
+Rationale:  While  it  is unusual for a reverse lookup to go
+for records  other  than  PTR  records  (or  possibly  CNAME
+records, for RFC 2317 classless delegation), there's no rea-
+son why it can't.  The TXT record is  a  temporary  stand-in
+for  (we  hope, someday) a new DNS record for SG identifica-
+tion and keying.  Keeping the setup  process  fast  requires
+minimizing  the  number  of DNS lookups, hence the desire to
+put all the information in one place.
+
+Rationale: The use of RFC 1464  notation  avoids  collisions
+with other uses of TXT records.  The ``X-'' in the attribute
+name indicates that this format is tentative and  experimen-
+tal;  this design will probably need modification after ini-
+tial experiments.  The format is chosen with an eye on even-
+tual  binary  encoding.   Note,  in particular, that the TXT
+record normally contains the address of the SG, not (repeat,
+not)  its  name.   Name-to-address  conversion is the job of
+whatever generates the TXT record, which is expected to be a
+program,  not a human--this is conceptually a binary record,
+temporarily using a text encoding.  The  ``@fqdn''  form  of
+the  SG identity is for specialized uses and is never mapped
+to an address.
+
+Ahem: A DNS  TXT  record  contains  one  or  more  character
+strings, but RFC 1035 does not describe exactly how a multi-
+string TXT record is interpreted.  This is relevant  because
+a  string can be at most 255 characters, and public keys can
+exceed this.  Empirically, the standard pattern is that each
+string  which  is  both less than 255 characters and not the
+final string of the record should have a blank  appended  to
+it,  and  the  strings of the record should then be concate-
+nated.  (This observation is based on how BIND 8  transforms
+a TXT record from text to DNS binary.)
+
+2.3.2.  KEY
+
+An opportunistic-encryption KEY record is an Authentication-
+permitted,  Entity  (host),  non-Signatory,  IPsec,  RSA/MD5
+record  (that  is,  its first four bytes are 0x42000401), as
+per RFCs 2535 and 2537.  KEY records with other flags,  pro-
+tocol, or algorithm values are ignored.
+
+
+
+
+
+Draft 4                  3 May 2001                       10
+
+
+
+
+
+                  Opportunistic Encryption
+
+
+Rationale:  Unfortunately,  the public key has to be associ-
+ated with the SG,  not  the  client  host  behind  it.   The
+Responder  does  not  know which client it is supposed to be
+representing, or which client the Initiator is representing,
+until far too late.
+
+Ahem: Per-client keys would reduce vulnerability to key com-
+promise, and simplify key changes, but  they  would  require
+changes  to  IKE  Phase 1, to separately identify the SG and
+its initial client(s).  (At present, the  client  identities
+are  not  known  to the Responder until IKE Phase 2.)  While
+the current IKE standard does not actually specify  (!)  who
+is  being  identified by identity payloads, the overwhelming
+consensus is that they identify the SG, and as seen earlier,
+this has important uses.
+
+2.3.3.  Summary
+
+For reference, the minimum set of DNS records needed to make
+this all work is either:
+
+1.  TXT in Destination reverse  map,  identifying  Responder
+    and providing public key.
+
+2.  KEY in Initiator reverse map, providing public key.
+
+3.  TXT  in  Source  reverse  map, verifying relationship to
+    Initiator.
+
+or:
+
+1.  TXT in Destination reverse map, identifying Responder.
+
+2.  KEY in Responder reverse map, providing public key.
+
+3.  KEY in Initiator reverse map, providing public key.
+
+4.  TXT in Source reverse  map,  verifying  relationship  to
+    Initiator.
+
+Slight  complications  ensue  for dynamic addresses, lack of
+control over reverse maps, etc.
+
+2.3.4.  Implementation
+
+In the long run, we need either a tree of trust or a web  of
+trust,  so  we can trust our DNS data.  The obvious approach
+for DNS is a tree of trust, but there are various  practical
+problems  with running all of this through the root servers,
+and a web of trust is arguably more robust anyway.  This  is
+logically  independent  of  opportunistic  encryption, and a
+separate design proposal will be prepared.
+
+
+
+
+
+Draft 4                  3 May 2001                       11
+
+
+
+
+
+                  Opportunistic Encryption
+
+
+Interim stages of implementation of this will require a  bit
+of  thought.   Notably, we need some way of dealing with the
+lack of fully signed DNSSEC  records  right  away.   Without
+user interaction, probably the best we can do is to remember
+the results of old fetches, compare them to the  results  of
+new  fetches,  and  complain  and  disbelieve  all  of it if
+there's a mismatch.  This does mean that somebody  who  gets
+fake  data  into our very first fetch will fool us, at least
+for a while, but that seems an acceptable tradeoff.   (Obvi-
+ously  there  needs to be a way to manually flush the remem-
+bered results for a  specific  host,  to  permit  deliberate
+changes.)
+
+2.4.  Responders Without Credentials
+
+In  cases  where the Destination simply does not control its
+DNS reverse-map entries,  there  is  no  verifiable  way  to
+determine  a  suitable SG.  This does not make communication
+utterly impossible, though.
+
+Simply attempting negotiation directly with the  host  is  a
+last  resort.   (An  aggressive implementation might wish to
+attempt it in parallel,  rather  than  waiting  until  other
+options  are  known  to  be unavailable.)  In particular, in
+many cases involving dynamic addresses, it  will  work.   It
+has  the  disadvantage of delaying the discovery that oppor-
+tunistic encryption is entirely  impossible,  but  the  case
+seems common enough to justify the overhead.
+
+However, there are policy issues here either way, because it
+is possible to impersonate such a host.  The host can supply
+an  FQDN identity and verify its right to use that identity,
+but except by prearrangement, there is no way to verify that
+the  FQDN  is  the right one for that IP address.  (The data
+from forward lookups may be controlled by people who do  not
+own  the  address, so it cannot be trusted.)  The encryption
+is still solid, though, so in many cases this may be useful.
+
+2.5.  Failure of Opportunism
+
+When  there is no way to do opportunistic encryption, a pol-
+icy issue arises: whether to put in a bypass  (which  allows
+plaintext  traffic  through)  or a block (which discards it,
+perhaps with notification back to the sender).   The  choice
+is  very  much  a  matter of local policy, and may depend on
+details such as the higher-level protocol being  used.   For
+example,  an  SG might well permit plaintext HTTP but forbid
+plaintext Telnet, in which case both a block  and  a  bypass
+would be set up if opportunistic encryption failed.
+
+A  bypass/block  must,  in practice, be treated much like an
+IPsec tunnel.  It should persist for a while, so that  high-
+overhead  processing  doesn't  have  to  be  done  for every
+packet, but should go away eventually to  return  resources.
+
+
+
+Draft 4                  3 May 2001                       12
+
+
+
+
+
+                  Opportunistic Encryption
+
+
+It  may  be simplest to treat it as a degenerate tunnel.  It
+should have a relatively long lifetime (say 6h) to keep  the
+frequency  of  negotiation attempts down, except in the case
+where the other SG simply did not respond  to  IKE  packets,
+where  the  lifetime should be short (say 10min) because the
+other SG is presumably down and might come  back  up  again.
+(Cases  where the other SG responded to IKE with unauthenti-
+cated error reports like ``port  unreachable''  are  border-
+line,  and  might  deserve  to be treated as an intermediate
+case: while such reports cannot be trusted unreservedly,  in
+the  absence of any other response, they do give some reason
+to suspect that the other SG is unable or unwilling to  par-
+ticipate in opportunistic encryption.)
+
+As  noted  in section 2.1, one might think that arrival of a
+plaintext incoming packet should cause a bypass/block to  be
+set  up  for its source host: such a packet is almost always
+followed by an outgoing reply packet; the incoming packet is
+clear  evidence  that opportunistic encryption is not avail-
+able at the other end; attempting it  will  waste  resources
+and  delay  traffic to no good purpose.  Unfortunately, this
+means that anyone out on the Internet who can forge a source
+address  can  prevent  encrypted communication!  Since their
+source addresses are not  authenticated,  plaintext  packets
+cannot be taken as evidence of anything, except perhaps that
+communication from that host is likely to occur soon.
+
+There needs to be a way for local administrators to remove a
+bypass/block  ahead  of  its  normal expiry time, to force a
+retry after a problem at the other end is known to have been
+fixed.
+
+2.6.  Subnet Opportunism
+
+In principle, when the Source or Destination host belongs to
+a subnet and the corresponding SG is willing to provide tun-
+nels  to the whole subnet, this should be done.  There is no
+extra overhead,  and  considerable  potential  for  avoiding
+later  overhead  if  similar communication occurs with other
+members of the subnet.  Unfortunately, at the moment, oppor-
+tunistic  tunnels  can  only have degenerate subnets (single
+hosts) at their ends.  (This does, at least, set up the key-
+ing channel, so that negotiations for tunnels to other hosts
+in the same subnets will be considerably faster.)
+
+The crucial problem is step 11 of section 2.2: the Responder
+must  verify  that  the Initiator is authorized to represent
+the Source, and this is  impossible  for  a  subnet  because
+there  is  no way to do a reverse lookup on it.  Information
+in DNS records for a name or  a  single  address  cannot  be
+trusted, because they may be controlled by people who do not
+control the whole subnet.
+
+
+
+
+
+Draft 4                  3 May 2001                       13
+
+
+
+
+
+                  Opportunistic Encryption
+
+
+Ahem: Except in the special case of a  subnet  masked  on  a
+byte  boundary  (in  which  case RFC 1035's convention of an
+incomplete in-addr.arpa name could be used),  subnet  lookup
+would need extensions to the reverse-map name space, perhaps
+along the lines of that commonly done for RFC  2317  delega-
+tion.   IPv6  already  has  suitable  name syntax, as in RFC
+2874, but has no specific provisions for subnet  entries  in
+its  reverse  maps.   Fixing all this is is not conceptually
+difficult, but is  logically  independent  of  opportunistic
+encryption, and will be proposed separately.
+
+A less-troublesome problem is that the Initiator, in step 10
+of 2.2, must know exactly what  subnet  is  present  on  the
+Responder's  end  so  he  can  propose a tunnel to it.  This
+information could be included in the TXT record of the  Des-
+tination (it would have to be verified with a subnet lookup,
+but that could be done in parallel with  other  operations).
+The Initiator presumably can be configured to know what sub-
+net(s) are present on its end.
+
+2.7.  Option Settings
+
+IPsec and IKE have far too many useless options, and  a  few
+useful  ones.  IKE negotiation is quite simplistic, and can-
+not handle even simple discrepancies between  the  two  SGs.
+So it is necessary to be quite specific about what should be
+done and what should be proposed,  to  guarantee  interoper-
+ability  without  prearrangement or other negotiation proto-
+cols.
+
+Rationale: The prohibition of other negotiations  is  simply
+because there is no time.  The setup algorithm (section 2.2)
+is lengthy already.
+
+[Open question: should opportunistic  IKE  use  a  different
+port than normal IKE?]
+
+Somewhat arbitrarily and tentatively, opportunistic SGs must
+support Main Mode, Oakley group 5 for D-H,  3DES  encryption
+and  MD5  authentication  for  both  ISAKMP  and  IPsec SAs,
+RSA/MD5 digital-signature authentication with  keys  between
+2048  and  8192  bits,  and  ESP  doing  both encryption and
+authentication.  They must do key PFS in Quick Mode, but not
+identity  PFS.   They  may  support IPComp, preferably using
+Deflate, but must not insist on it.  They may support AES as
+an alternative to 3DES, but must not insist on it.
+
+Rationale:  Identity PFS essentially requires establishing a
+complete new keying channel for each new tunnel, but key PFS
+just  does  a new Diffie-Hellman exchange for each rekeying,
+which is relatively cheap.
+
+Keying channels must remain in existence at least as long as
+any  tunnel  created with them remains (they are not costly,
+
+
+
+Draft 4                  3 May 2001                       14
+
+
+
+
+
+                  Opportunistic Encryption
+
+
+and keeping the management path up and available  simplifies
+various issues).  See section 3.1 for related issues.  Given
+the use of key PFS, frequent rekeying does not seem critical
+here.   In the absence of strong reason to do otherwise, the
+Initiator  should  propose  rekeying  at  8hr-or-1MB.    The
+Responder  must accept any proposal which specifies a rekey-
+ing time between 1hr and 24hr inclusive and a rekeying  vol-
+ume between 100KB and 10MB inclusive.
+
+Given  the  short  expected useful life of most tunnels (see
+section 3.1), very few of them will survive long  enough  to
+be  rekeyed.   In  the absence of strong reason to do other-
+wise, the Initiator should propose rekeying at 1hr-or-100MB.
+The  Responder  must  accept  any proposal which specifies a
+rekeying time between 10min and 8hr inclusive and a rekeying
+volume between 1MB and 1000MB inclusive.
+
+It  is  highly  desirable  to  add some random jitter to the
+times of actual rekeying attempts, to break  up  ``convoys''
+of rekeying events; this and certain other aspects of robust
+rekeying practice will be the subject of a  separate  design
+proposal.
+
+Rationale:  The numbers used here for rekeying intervals are
+chosen quite arbitrarily and  should  be  re-assessed  after
+some implementation experience is gathered.
+
+3.  Renewal and Teardown
+
+3.1.  Aging
+
+When to tear tunnels down is a bit problematic, but if we're
+setting up a potentially unbounded number of them,  we  have
+to tear them down somehow sometime.
+
+Set a short initial tentative lifespan, say 1min, since most
+net flows in fact  last  only  a  few  seconds.   When  that
+expires,  look to see if the tunnel is still in use (defini-
+tion: has had traffic, in either direction, in the last half
+of  the  tentative  lifespan).   If so, assign it a somewhat
+longer tentative lifespan,  say  20min,  after  which,  look
+again.   If not, close it down.  (This tentative lifespan is
+independent of rekeying; it is just the time when  the  tun-
+nel's future is next considered.  This should happen reason-
+ably  frequently,  unlike  rekeying,  which  is  costly  and
+shouldn't  be  too frequent.)  Multi-step backoff algorithms
+are not worth the trouble; looking every 20min doesn't  seem
+onerous.
+
+If  the security gateway and the client host are one and the
+same, tunnel teardown decisions might wish to pay  attention
+to  TCP  connection  status,  as  reported  by the local TCP
+layer.  A still-open TCP connection is  almost  a  guarantee
+that  more  traffic  is coming, while the demise of the only
+
+
+
+Draft 4                  3 May 2001                       15
+
+
+
+
+
+                  Opportunistic Encryption
+
+
+TCP connection through a tunnel is a strong hint  that  none
+is.   If  the  SG and the client host are separate machines,
+though,  tracking  TCP  connection  status  requires  packet
+snooping,  which is complicated and probably not worthwhile.
+
+IKE keying channels likewise are torn down when  it  appears
+the  need  has  passed.   They always linger longer than the
+last tunnel they administer, in case they are needed  again;
+the  cost of retaining them is low.  Other than that, unless
+the number of keying channels on the SG gets large,  the  SG
+should  simply retain all of them until rekeying time, since
+rekeying is the only costly event.  When about  to  rekey  a
+keying  channel  which has no current tunnels, note when the
+last actual keying-channel traffic occurred, and  close  the
+keying  channel  down  if it wasn't in the last, say, 30min.
+When rekeying a keying channel (or  perhaps  shortly  before
+rekeying  is  expected),  Initiator and Responder should re-
+fetch the public keys used for  SG  authentication,  against
+the possibility that they have changed or disappeared.
+
+See section 2.7 for discussion of rekeying intervals.
+
+Given  the  low user impact of tearing down and rebuilding a
+connection (a tunnel or a keying channel), rekeying attempts
+should  not  be  too persistent: one can always just rebuild
+when needed, so heroic efforts to preserve an existing  con-
+nection  are  unnecessary.   Say, try every 10s for a minute
+and every minute for 5min, and then give up and declare  the
+connection  (and  all  other  connections  to that IKE peer)
+dead.
+
+Rationale: In future, more sophisticated, versions  of  this
+protocol,  examining  the initial packet might permit a more
+intelligent guess at the tunnel's useful life.  HTTP connec-
+tions in particular are notoriously bursty and repetitive.
+
+Rationale:  Note that rekeying a keying connection basically
+consists of building a new keying connection  from  scratch,
+using IKE Phase 1, and abandoning the old one.
+
+3.2.  Teardown and Cleanup
+
+Teardown  should  always  be coordinated with the other end.
+This means interpreting and sending Delete notifications.
+
+On receiving a Delete for the outbound SAs of a  tunnel  (or
+some  subset  of  them), tear down the inbound ones too, and
+notify the other end with a Delete.  Tunnels need to be con-
+sidered as bidirectional entities, even though the low-level
+protocols don't think of them that way.
+
+When the deletion is initiated locally,  rather  than  as  a
+response  to  a received Delete, send a Delete for (all) the
+inbound SAs  of  a  tunnel.   If  no  responding  Delete  is
+
+
+
+Draft 4                  3 May 2001                       16
+
+
+
+
+
+                  Opportunistic Encryption
+
+
+received  for  the outbound SAs, try re-sending the original
+Delete.  Three tries spaced 10s  apart  seems  a  reasonable
+level  of effort.  (Indefinite persistence is not necessary;
+whether the other end isn't cooperating because  it  doesn't
+feel  like  it, or because it is down/disconnected/etc., the
+problem will eventually be cleared up by other means.)
+
+After rekeying, transmission should switch to using the  new
+SAs  (ISAKMP or IPsec) immediately, and the old leftover SAs
+should be cleared out promptly  (and  Deletes  sent)  rather
+than  waiting  for them to expire.  This reduces clutter and
+minimizes confusion.
+
+Since there  is  only  one  keying  channel  per  remote  IP
+address,  the  question of whether a Delete notification has
+appeared on a ``suitable'' keying channel does not arise.
+
+Rationale: The pairing of Delete  notifications  effectively
+constitutes  an  acknowledged Delete, which is highly desir-
+able.
+
+3.3.  Outages and Reboots
+
+Tunnels sometimes go down because the other end crashes,  or
+disconnects,  or  has  a network link break, and there is no
+notice of this in the general case.  (Even in the event of a
+crash  and  successful reboot, other SGs don't hear about it
+unless the rebooted SG has specific reason to talk  to  them
+immediately.)  Over-quick response to temporary network out-
+ages is undesirable...  but note that a tunnel can  be  torn
+down and then re-established without any user-visible effect
+except a pause in traffic, whereas if one end  does  reboot,
+the  other  end  can't  get packets to it at all (except via
+IKE) until the situation is noticed.  So a bias toward quick
+response  is  appropriate,  even  at  the cost of occasional
+false alarms.
+
+Heartbeat mechanisms are somewhat unsatisfactory  for  this.
+Unless  they are very frequent, which causes other problems,
+they do not detect the problem promptly.
+
+Ahem: What is really wanted  is  authenticated  ICMP.   This
+might  be  a case where public-key encryption/authentication
+of network packets is the right thing  to  do,  despite  the
+expense.
+
+In the absence of that, a two-part approach seems warranted.
+
+First, when an SG receives an IPsec packet that is addressed
+to  it,  and  otherwise  appears  healthy,  but specifies an
+unknown SA and is from a host that  the  receiver  currently
+has  no  keying  channel  to,  the  receiver must attempt to
+inform the sender via an  IKE  Initial-Contact  notification
+(necessarily  sent  in plaintext, since there is no suitable
+
+
+
+Draft 4                  3 May 2001                       17
+
+
+
+
+
+                  Opportunistic Encryption
+
+
+keying channel).  This must be severely rate-limited on both
+ends; one notification per SG pair per minute seems ample.
+
+Second,  there  is an obvious difficulty with this: the Ini-
+tial-Contact notification is unauthenticated and  cannot  be
+trusted.   So it must be taken as a hint only: there must be
+a way to confirm it.
+
+What is needed here is something that's desirable for debug-
+ging and testing anyway: an IKE-level ping mechanism.  Ping-
+ing direct at the IP level instead will not tell us about  a
+crash/reboot event.  Sending pings through tunnels has vari-
+ous complications (they should stop at the far mouth of  the
+tunnel  instead  of  going  on  to a subnet; they should not
+count against idle timers; etc.).  What is needed is a  con-
+tinuity check on a keying channel.  (This could also be used
+as a heartbeat, should that seem useful.)
+
+IKE Ping delivery need not  be  reliable,  since  the  whole
+point  of  a  ping  is simply to provoke an acknowledgement.
+They should preferably be authenticated, but it is not clear
+that  this is absolutely necessary, although if they are not
+they need encryption plus a timestamp or a  nonce,  to  foil
+replay  mischief.   How  they are implemented is a secondary
+issue, and a separate design proposal will be prepared.
+
+Ahem: Some existing implementations are already using  (pri-
+vate)  notify value 30000 (``LIKE_HELLO'') as ping and (pri-
+vate) notify value 30002 (``SHUT_UP'') as ping reply.
+
+If an IKE Ping gets no response, try some (say 8) IP  pings,
+spaced a few seconds apart, to check IP connectivity; if one
+comes back, try another IKE Ping; if that gets no  response,
+the  other  end probably has rebooted, or otherwise been re-
+initialized, and its tunnels and keying channel(s) should be
+torn down.
+
+In  a  similar  vein, giving limited rekeying persistence, a
+short network outage could take some  tunnels  down  without
+disrupting  others.  On receiving a packet for an unknown SA
+from a host that a keying channel is currently open to, send
+that host a Invalid-SPI notification for that SA.  The other
+host can then tear down the half-torn-down tunnel, and nego-
+tiate a new tunnel for the traffic it presumably still wants
+to send.
+
+Finally, it would be helpful if SGs  made  some  attempt  to
+deal  intelligently  with crashes and reboots.  A deliberate
+shutdown should include an attempt to notify all  other  SGs
+currently  connected by keying channels, using Deletes, that
+communication is about to fail.  (Again, these will be taken
+as  teardowns;  attempts  by  the other SGs to negotiate new
+tunnels as replacements should be ignored  at  this  point.)
+And   when   possible,   SGs   should  attempt  to  preserve
+
+
+
+Draft 4                  3 May 2001                       18
+
+
+
+
+
+                  Opportunistic Encryption
+
+
+information about currently-connected  SGs  in  non-volatile
+storage,  so  that  after a crash, an Initial-Contact can be
+sent to previous partners to indicate  loss  of  all  previ-
+ously-established connections.
+
+4.  Conclusions
+
+This  design  appears to achieve the objective of setting up
+encryption with strangers.  The authentication aspects  also
+seem  adequately  addressed  if the destination controls its
+reverse-map DNS entries and the DNS data itself can be reli-
+ably  authenticated as having originated from the legitimate
+administrators of that subnet/FQDN.  The authentication sit-
+uation is less satisfactory when DNS is less helpful, but it
+is difficult to see what else could be done about it.
+
+5.  References
+
+[TBW]
+
+6.  Appendix:  Separate Design Proposals TBW
+
+o  How can we build a web of trust with DNSSEC?   (See  sec-
+   tion 2.3.4.)
+
+o  How  can  we extend DNS reverse lookups to permit reverse
+   lookup on a subnet?  (Both address and mask  must  appear
+   in the name to be looked up.)  (See section 2.6.)
+
+o  How  can  rekeying  be done as robustly as possible?  (At
+   least partly, this is just documenting current  FreeS/WAN
+   practice.)  (See section 2.7.)
+
+o  How  should IKE Pings be implemented?  (See section 3.3.)
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Draft 4                  3 May 2001                       19
+
+
diff --git a/doc/opportunism.howto b/doc/opportunism.howto
new file mode 100644
index 000000000..14b5ed5a2
--- /dev/null
+++ b/doc/opportunism.howto
@@ -0,0 +1,415 @@
+FreeS/WAN Opportunism HowTo
+===========================
+
+RCSID $Id: opportunism.howto,v 1.1 2004/03/15 20:35:21 as Exp $
+
+D. Hugh Redelmeier
+
+
+FreeS/WAN, the LINUX IPSEC implementation, is intended to allow
+systems to connect through secure tunnels with or without prearrangement.
+We use the term "Opportunism" to describe tunnels set up without
+prearrangement.  This HowTo will show you how to set your system up
+for Opportunism.
+
+You are expected to already have built and used FreeS/WAN.  Much more
+information about FreeS/WAN is provided at http://www.freeswan.org.
+This document is only intended to describe the support for
+opportunism.  The features described here are available in FreeS/WAN
+version 1.91 or later (there were important bugs up until 1.95).
+
+For a more complete description of the design of Opportunism, see our
+paper "Opportunistic Encryption" (available as opportunism.spec in
+the same directory as this document).
+
+
+Steps
+=====
+
+- Understand what you are attempting.  Security requires care.
+  Problems are hard to untangle.  Be sure to read the last section
+  "Important Limitations".
+
+- Install FreeS/WAN (version 1.91 or later).
+
+- Add appropriate DNS records to your reverse-map domains.
+
+- Add suitable conns to /etc/ipsec.conf.
+
+- Try it out: start it, monitor it, fix it.
+
+- Now you understand the system better, reread "Important Limitations"
+
+These steps are also an outline of this document.
+
+
+Theory
+======
+
+FreeS/WAN runs on a machine that we will call a "Security Gateway".
+Usually this machine is a gateway to the internet.  It may be that the
+only machine for which it provides gateway services is itself, but
+that is just a special case -- we will still call it a Security
+Gateway.
+
+A FreeS/WAN Security Gateway implements secure tunnels to other
+Security Gateways.  One problem is to arrange for these tunnels to be
+created and used.  If opportunism is enabled, a Security Gateway
+running FreeS/WAN will intercept the first outbound packet to a
+particular destination (IP address), and try to negotiate a security
+tunnel suitable for traffic to that destination.
+
+To make this work going the other way, the Security Gateway must be
+willing to negotiate with peers trying to protect traffic initiated
+from their side.
+
+The first novel problem is that our Security Gateway needs to discover
+the IP address of the other Security Gateway for the packet that
+prompted the negotiation.  Oh, and quickly discover if there is none
+-- that negotiation will be impossible.
+
+The second novel problem is that our Security Gateway needs to
+authenticate the other Security Gateway.  This authentication needs to
+ensure that the other Security Gateway is who it claims to be AND that
+it is authorized to represent the client for which it claims to be the
+gateway.
+
+The roles in a particular negotiation are:
+     Source----Initiator----...----Responder----Destination
+
+The Source and Destination are endpoints of the traffic that is to be
+protected.  The Source is the one that happened to send the first
+packet of traffic.  Neither needs to be aware of IPSEC or FreeS/WAN.
+That is the job of their respective Security Gateways, Initiator and
+Responder.  The names "Initiator" and "Responder" match those used in
+the IPSEC standards for IKE negotiation.  Remember that Source and
+Initiator could be the same machine; similarly, Destination and
+Responder could be the same.  All traffic from Source or Destination
+must flow through their Security Gateways if it is to be considered
+for protection.  These roles are fluid -- they can be different for
+each negotiation.
+
+We use the DNS (the Domain Name System) as a distributed database to
+publish the required information.
+
+
+DNS Records Required
+====================
+
+See section 2.3 of "Opportunistic Encryption" for a fuller
+explanation.
+
+Generally, we need to add records to the reverse-map DNS entries for
+the client machine and its Security Gateway machine.  There are
+special cases that are exceptions.
+
+A Security Gateway that is going to initiate an Opportunistic
+negotiation needs to provide a way for the Responding SG to find a
+public key for the Initiator to allow authentication.  This is
+accomplished by putting the public key in a KEY record in the
+reverse-map of the Initiator.  Conveniently, the KEY record can
+be generated by the ipsec_showhostkey(8) command.
+
+	ipsec showhostkey
+
+Here is an example of the output, with many characters of the key
+itself left out:
+
+	; RSA 2048 bits   xy.example.com   Sat Apr 15 13:53:22 2000
+	xy.example.com.   IN   KEY   0x4200 4 1 AQOF8tZ2...+buFuFn/
+
+=> Copy the output of the command into the zone information for the
+   reverse-map of the Security Gateway's public interface.
+
+Each client that is to be protected by Opportunistic Encryption must
+include a special TXT record in its reverse-map.  The
+ipsec_showhostkey(8) command can create this too.  Remember:  this
+command must be run on the Security Gateway where the ipsec.secrets
+file resides.  You must tell the command what IP address to put in the
+TXT record.  The IP address is that of the Security Gateway.
+
+	ipsec showhostkey --txt 10.11.12.13
+
+This command might produce the output:
+
+	; RSA 2048 bits   xy.example.com   Sat Apr 15 13:53:22 2000
+	IN TXT  "X-IPsec-Server(10)=10.11.12.13 AQOF8tZ2...+buFuFn/"
+
+- The quotes matter: this is a single string, as far as DNS is
+  concerned.
+
+- The X-IPsec-Server is a prefix that signifies that the TXT record
+  contains Opportunism configuration information.
+
+- The (10) specifies a precedence for this record.  This is similar
+  to MX record preferences.  Lower numbers have stronger preference.
+
+- 10.11.12.13 specifies the IP address of the Security Gateway for
+  this machine.
+
+- AQOF8tZ2...+buFuFn/ is the (shortened) encoding of the RSA Public
+  key of the Security Gateway.
+
+=> Added this output to the zone information for the reverse-map for
+   each client machine.  This gets a bit dull and repetitive.
+
+Unfortunately, not every administrator has control over the contents
+of the reverse-map.  The only case where we can work around this is
+where the Initiator has no suitable reverse map.  In this case, the
+Source's TXT record gives @FQDN ("Fully Qualified Domain Name") in
+place of its Security Gateway's IP address.  This FQDN must match the
+ID-payload used by the Initiator.  Furthermore, a forward lookup for a
+KEY record on the FQDN must yield the Initiator's public key.
+
+If the Source's IP address is the same as the Initiator's IP address,
+the Responder will assume that the Initiator is authorized to talk for
+the Source (itself!).  In this case, the Responder won't try to fetch
+the Source's TXT record from the reverse map for the Source's IP
+address.
+
+These two features can be combined.  If the Source and the Initiator
+are the same (i.e. the Security Gateway is protecting itself), and the
+Initiator uses a @FQDN ID (leftid=@example.com), then the
+administrator of that machine need only have installed a KEY record in
+the FQDN domain -- he need not control any reverse map.
+
+Obscure fact: the forward lookup is only done by a Responder, and then
+only when the Initiator's ID payload specifies the FQDN.  There is no
+provision for a Responder with no control over its reverse-map.
+
+Beware: DNS changes sometimes take a long time to propagate.
+
+
+Configuring FreeS/WAN
+=====================
+
+To enable opportunism, you must include a suitable conn in
+/etc/ipsec.conf and you must enable it.
+
+A suitable conn looks roughly like an ordinary conn.  It more closely
+resembles a Road Warrior conn (a Road Warrior conn is one that has a
+wildcard %any specified as the other Security Gateway).  But in the
+Opportunistic case, both the other Security Gateway AND its client are
+unknown ahead of time.
+
+conn client-to-anyone	# for our client subnet
+	leftsubnet=10.3.2.1.0/24	# any single client in our subnet
+	also=sg-to-anyone	# rest is same as for SG
+
+conn sg-to-anyone	# for our Security Gateway
+	left=%defaultroute	# our SG (defaults leftnexthop too)
+	right=%opportunistic
+	authby=rsasig	# almost always the right choice
+	keyingtries=2	# don't be persistent -- peer might disappear
+	auto=route	# enable at ipsec startup
+
+(%defaultroute only works if you have specified
+interfaces=%defaultroute.  Since this isn't the topic of the howto,
+you will have to look at the other documentation to find out how to
+handle other cases.)
+
+You can have any number of opportunistic conns, but generally it only
+makes sense to have one for each client subnet and one for the
+Security Gateway itself.
+
+Currently only one interface may be used for opportunism: Pluto knows
+nothing about routing, so would be unable to choose amongst several.
+Almost certainly our side's nexthop must be predetermined
+(%defaultroute will do that).
+
+Note: the routing done for outbound Opportunism will catch any packets
+not covered by a more specific route.  This is what you want for
+packets that are also covered by an eroute.  But packets caught by the
+route and not an eroute will be subject to the no-eroute policy of
+KLIPS, which defaults to %drop.  Remember that routing ignores the
+packet's source address, but erouting pays attention to it.  So if
+Opportunism is enabled, it is best to provide for it covering all IP
+addresses behind or on the Security Gateway.
+
+To enable these conns for inbound opportunistic negotiation, they must be
+--added.  auto=add would accomplish this at ipsec startup, but if you cannot
+wait:
+	ipsec auto --add sg-to-anyone
+	ipsec auto --add client-to-anyone
+
+To enable these conns for outbound opportunistic negotiation, they must
+be both --added and --routed.  Outbound packets will then be trapped
+and will trigger negotiation.  auto=route would cause this to happen
+at startup, but if you wish to do this at another time:
+	ipsec auto --add sg-to-anyone
+	ipsec auto --add client-to-anyone
+	ipsec auto --route sg-to-anyone
+	ipsec auto --route client-to-anyone
+
+
+Getting DNS Through
+===================
+
+There is a serious chicken-and-egg problem.  Outbound Opportunism blocks
+communication with an IP address until Pluto discovers whether that IP
+address can have an IPSEC connection negotiated.  This discovery takes
+DNS queries.  These DNS queries might involve communicating with
+arbitrary IP addresses.  Thus we require DNS queries to succeed before
+any communication succeeds, including those same DNS queries!  The way
+out of this conundrum is to exempt at least some DNS query IP traffic
+from Opportunism.
+
+There are several possible solutions, all of which have advantages and
+disadvantages.
+
+1. If you use a single machine, outside your Security Gateway, as DNS
+server, you can build a clear path (or even an IPSEC tunnel, but not
+opportunistically) directly to that machine.
+
+- you could use a type=passthrough conn to provide a clear path
+  between your machine and the DNS machine.
+
+- better still, you could explicitly create an IPSEC connection to
+  your DNS server.  Just be sure that Pluto does not need to access
+  DNS to find the IP addresses or RSA public keys for that connection!
+
+- you could install an explicit route to the DNS machine through
+  your public interface (not ipsecN).  This will bypass KLIPS
+  processing.  You might have to adjust your firewall.  For example:
+
+  	route add host -net ns.example.com gw gw.example.com dev eth1
+
+2. Generally, it is better to run DNS on your Security Gateway.  This
+leads to a need for non-opportunistic paths to an arbitrary number of
+DNS servers in the internet.  One way to accomplish this is to NOT
+have outbound opportunism cover the SG itself, but only the subnet
+behind it.  In other words, leave out the
+	ipsec auto --route sg-to-anyone
+You must also add a type=passthrough eroute specifically for
+sg-to-anyone (without this, the traffic will be handled by the KLIPS
+no-eroute policy).
+
+3. It is actually possible to use a single machine inside your client
+subnet as a DNS server.  The techniques listed in 1 could be used to
+let it communicate with other DNS servers without interference.  This
+might have advantages over 1 if the DNS machine *only* did DNS.
+Another technique (not often possible or reasonable) is to give this
+machine another route to the internet, one that avoids the SG.
+
+4. DNS queries will eventually time out and then Pluto will give up
+and establish %pass eroutes.  So communications should start flowing.
+
+We would like to have better solutions.  Perhaps we will in the
+future.  Suggestions are welcome.
+
+
+Figuring out what is going on
+=============================
+
+Since Opportunism lets your SG operate with less supervision, you may
+be puzzled by what it is up to.  The usual tools exist, but their use
+is more important.  To look at what Pluto is doing, use:
+	ipsec auto --status
+To look at what KLIPS is doing, use
+	ipsec look
+
+To just see the kernel's eroute table, look at the "file"
+/proc/net/ipsec_eroute.  It contains a description of all the eroutes
+in the kernel.  Here is an example:
+
+10         10.2.1.0/24      -> 0.0.0.0/0          => %trap
+259        10.2.1.115/32    -> 10.19.75.161/32    => tun0x1002@10.19.75.145
+71         10.44.73.97/32   -> 0.0.0.0/0          => %trap
+4119       10.44.73.97/32   -> 10.114.121.41/32   => %pass
+
+You read each line as: a packet from within the first subnet, destined
+for the second subnet, will be processed by the Security Association
+Identity (SAID) specified last.  The first column is the number of
+(outbound) packets processed by this eroute.
+
+For shunt eroutes, the SAID is printed as just the type of shunt:
+%pass	pass the packet through with no processing
+%drop	discard the packet
+%reject	discard the packet and notify sender
+%hold	keep the last packet; discard others
+%trap	cause any trapped packet to generate a PF_KEY ACQUIRE
+	to request negotiation; install a corresponding %hold
+	shunt and attach this packet to the %hold
+
+For other eroutes, the SAID is printed as a triple: protocol (three
+letters), SPI (32-bit number in hex), and destination IP address.
+Protocols include:
+
+tun	IP in IP encapsulation (used for most tunnels)
+esp	ESP encapsulation -- part of an IPSEC SA group
+ah	AH packet authentication -- part of an IPSEC SA group
+
+So, looking at our sample eroutes:
+
+10         10.2.1.0/24      -> 0.0.0.0/0          => %trap
+
+	This is a TRAP (int0x104) shunt eroute.  It was installed by
+	Pluto so that it can catch all traffic from its client subnet
+	to the world at large.  Ten outbound packets have been trapped.
+
+259        10.2.1.115/32    -> 10.19.75.161/32    => tun0x1002@10.19.75.145
+
+	This is a tunnel eroute: packets from 10.2.1.115 (within
+	our client subnet) going to 10.19.75.161 will be encrypted
+	and sent to the peer SG 10.19.75.145.  This was the product
+	of an Opportunistic negotiation (a hint is that each client
+	subnet has only one member).  259 packets have been sent
+	through this tunnel.
+
+71         10.44.73.97/32   -> 0.0.0.0/0          => %trap
+
+	This is another TRAP shunt eroute.  It is to catch traffic
+	from the Security Gateway to the world.  It has caught
+	71 outbound packets.
+
+4119       10.44.73.97/32   -> 10.114.121.41/32   => %pass
+
+	This is a %pass (0x100) shunt eroute.  It was installed when an
+	attempted Opportunistic negotiation failed because the reverse
+	domain of 10.114.121.41 had no suitable TXT record.  4119
+	outbound packets have been passed.
+
+
+Important Limitations
+=====================
+
+Pluto's DNS lookup is synchronous (single-threaded).  Not only does
+this slow things down, but it turns out that in extreme cases where
+there are a lot of ACQUIRE messages from KLIPS at once, some of those
+messages can be lost and communications will be blocked by the %hold
+eroute that Pluto doesn't know about.  Pluto now looks every 2 minutes
+for any %holds that it missed.
+
+DNS lookup is not verified -- we don't use Secure DNS.  A spoofed DNS
+could compromise Opportunism.
+
+There are several new opportunities for Denial of Service attacks.
+For example, a Bad Guy could spray our system with pings with forged
+source addresses.  For each unique source address, our system would do
+a (synchronous!) DNS lookup.
+
+Once a %pass eroute is added for a failed negotiation, it will stay
+until it has been inactive for about 15 minutes.  The only activity
+that counts is outbound -- not surprising since a %pass only affects
+outbound traffic.
+
+If a destination's DNS entry specifies the information we need for
+negotiation, Pluto will not let communications proceed without
+negotiating a Security Tunnel.
+
+There is currently no way to tear down a tunnel that is no longer in
+use.  To add insult to injury, when the lifetime is about to be
+exceeded, the initiating Pluto will rekey!  Restarting will clear
+these out.  rekey=no doesn't solve this since SA expiry would be
+uncoordinated and hence cause packets to be lost.
+
+If one side of a Security Tunnel restarts, but doesn't initiate
+negotiation with its peer, the peer will not be able to communicate
+with it until the peer thinks the tunnel needs rekeying due to
+lifetime, or the restarted Security Gateway decides to negotiate for
+its own reasons.
+
+It isn't clear what firewall policies make sense with Opportunism.
+
+If VPN and Opportunism connections coexist, security policies
+implemented via a firewall can only distinguish traffic by IP address.
diff --git a/doc/opportunism.known-issues b/doc/opportunism.known-issues
new file mode 100644
index 000000000..90752dee3
--- /dev/null
+++ b/doc/opportunism.known-issues
@@ -0,0 +1,287 @@
+Known issues with Opportunistic Encryption                     Claudia Schmeing
+------------------------------------------
+
+
+This is an overview of known issues with OE.
+
+
+This document supplements:
+
+
+FreeS/WAN Quickstart Guide        doc/quickstart.html
+
+Opportunism HOWTO                 doc/opportunism.howto
+
+Opportunism spec                  doc/opportunism.spec
+
+Internet Draft                    doc/draft-richardson-ipsec-opportunistic.txt
+
+
+
+* Use the most recent Linux FreeS/WAN 2.x release from ftp.xs4all.nl 
+  to try OE.
+
+
+DESIGN LIMITATIONS
+
+
+* Because Opportunistic Encryption relies on DNS:
+  - to authenticate one FreeS/WAN to another, and
+  - to prove that we have the right to protect traffic for a given IP,
+  this authentication/authorization is only as strong as your DNS is 
+  secure.
+
+  Without secure DNS, OE protects against passive snooping only.
+  Because the public key and gateway information that FreeS/WAN gets from 
+  DNS is not authenticated, a man-in-the-middle attack is still possible.  
+  We hope that as DNSsec is widely adopted, OE with strong authentication
+  will become more widespread.
+
+  However, our software does not yet distinguish between strongly and weakly 
+  authenticated OE. This information might be useful for defining local 
+  security policy.
+
+
+* Denial of service attacks are possible against OE. If you rely on OE rather 
+  than VPN to connect several offices, a determined attacker could prevent you 
+  from communicating securely.
+
+
+* OE challenges the notion that all IPsec peers are "friends". With OE, 
+  strangers can potentially tunnel IPsec packets _through_ your defenses 
+  against cleartext packets. This may call for a re-visit to firewall policy.
+
+
+* FreeS/WAN only creates OE connections when it traps an outgoing packet.
+  Since most traffic is two-way, for most traffic, FreeS/WAN 2.x may soon 
+  trap an outgoing packet and create an IPsec connection to
+  protect both incoming and outgoing traffic. However, if a local 
+  FreeS/WAN box accepts inbound traffic from a remote peer but 
+  generates no outbound traffic in response, the local FreeS/WAN will not 
+  attempt to initiate OE. Of course, the peer may also initiate OE upon
+  trapping its own outbound traffic.
+  
+
+* OE is only as reliable as your DNS is.
+  
+  If your DNS service is flaky, you will not be able to reliably establish 
+  OE connections to known OE-capable peers.
+  
+  If you ping a peer, but your FreeS/WAN does not find a TXT record signifying 
+  the peer's ability to respond to OE negotiation), FreeS/WAN will not try to 
+  opportunistically initiate, and communication will fallback to clear.
+
+  For more secure and reliable DNS, we recommend that you run DNS
+  within your security perimeter, either on your security gateway, or
+  on a machine to which you have a VPN connection. It is also possible
+  to have your DNS server located elsewhere on your LAN, though this may
+  cause lag on startup.
+  
+  This mailing list message explains how to run a local caching name server:
+  http://lists.freeswan.org/pipermail/design/2003-January/004205.html
+ 
+  See also "Getting DNS through" in opportunism.howto
+  http://lists.freeswan.org/pipermail/design/2002-April/002285.html .
+
+
+
+CURRENT ISSUES
+
+* There are several special issues re: using OE when running FreeS/WAN with
+  kernel native IPsec, introduced in the 2.6 kernel. Please see 
+  doc/2.6.known-issues.
+
+* If A and B have an OE connection, but A is rebooted, normally A will try to 
+  re-connect to B and (if it has no DNS-related failures) it will succeed. 
+  But, if A is set up for responder-only OE, you will have a one-way 
+  connection until B notices that its original tunnel has expired. For details 
+  see:
+
+      http://lists.freeswan.org/pipermail/design/2002-May/002582.html
+      http://lists.freeswan.org/pipermail/design/2002-June/002610.html
+
+  TIP:  If an OE connection isn't behaving, you can recreate it with
+
+      ipsec whack --oppohere sourceIPaddress --oppothere targetIPaddress
+
+
+* There is no good clean facility to delete OE connections.
+  Available are:
+
+      ipsec auto --status to list connections
+      ipsec whack --deletestate to delete by state#.
+   
+
+* You may experience seeming gaps at rekey time. Once you generate traffic,
+  you will find that the OE connection returns.
+
+  By default, OE connections are not rekeyed; if they were we'd have a 
+  mountain of useless connections. As a consequence, if your OE connection is
+  idle at rekey time, it will go down until you generate further traffic.
+  To ensure prompt rekeying, you can run a ping thorough the OE tunnel.
+
+
+* At the moment, you can only run active OE on one physical interface.
+
+  Active means --routed, to trap outbound packets.  It is this route
+  that is a problem.
+
+  Untested theory: you can have multiple active OE conns, for different 
+  source addresses, but they all have to point their traffic out the single 
+  interface.
+
+  When responding: you can only define one OE connection (per host or subnet) 
+  in ipsec.conf, and that conn will apply to one interface. Normally this 
+  will be the public interface which your default route uses; it is, however, 
+  configurable.
+
+  Theoretically, it might make sense to select between multiple OE conns 
+  based on some criterion, such as address ranges. This might be useful for 
+  local OE, or in a complex routing scenario.
+
+  Currently, Pluto expects only one OE connection. If you add another,
+  Pluto may choose randomly between them, producing unpredictable results.
+
+
+* Building OE conns between nodes on a LAN is not possible.
+
+  This is a side effect of conflicts about ARP entries 
+  in the rt_cache and our "stupid routing tricks".
+  There is no known workaround at this time.
+
+  "Stupid routing tricks" are an ongoing issue, and should
+  go away in a future software revision.
+
+  See these explanations:
+      http://lists.freeswan.org/pipermail/design/2002-April/002285.html
+      http://lists.freeswan.org/pipermail/design/2002-August/003249.html
+
+
+* FreeS/WAN may not correctly follow a CNAME (Canonical Name) trail resulting
+  from reverse DNS delegation.
+
+  Solution: Use a recent Bind 9 (we tested with Bind snap-pre9.3) for the 
+  DNS services which the FreeS/WAN box relies on. 
+
+  Reason: This Bind correctly implements "implied helper support" for 
+  traditional DNS records, and so can follow a properly constructed CNAME 
+  record trail which ends in a TXT record. Thus, in cases where a reverse 
+  domain has been delegated, FreeS/WAN + Bind 9 can find a TXT record and 
+  create an OE connection.
+
+  For more on the problem, see "OLD ISSUES", below.
+
+
+* To make OE operation smoother, we may need a script that runs and warns 
+  if we have the reverse DNS records, but not the software running.
+  The reverse records advertise that we can do OE, but when the software is
+  not running this is false advertising.
+
+
+
+OLD ISSUES
+
+* Coterminal OE doesn't work in practise. This includes OE-in-WAVEsec.
+  Solved in 2.02.
+
+  Old diagnosis:
+
+  If you have coterminal OE connections (two OE connections which share
+  one endpoint), you should have use of one of the encrypted links, but it 
+  is not clear which one KLIPS will prefer. In particular, the behaviour 
+  may not be symmetrical.
+
+  Worse yet, it just seems to trip over itself and be generally
+  unworkable.
+
+  Weird but predictable:
+
+  If you have both a gateway and a host who advertise (via DNS) an 
+  ability to do OE you need to be serious about doing host-based
+  OE, or you will be stuck in initiator-only mode. If your host 
+  advertises but does not run OE, then when a peer tries to connect to 
+  your host, it will fail to clear. The peer will then not try to encrypt 
+  traffic bound for that host as it travels to the gateway. To remedy 
+  the situation, restart ipsec on the peer (or otherwise flush out 
+  the %pass eroute), and ping the peer from your host to initiate 
+  OE.
+
+
+* One-way connection was created on rekey. Solved in 2.0.
+
+  If one side (A) has a shorter _keylife_ than the other,
+  and that side also has _rekey=no_, then when the keylife has 
+  expired, it will expect that its peer (B) will make a new conn to replace 
+  the existing one. Unfortunately, B has no idea. 
+
+  B continues to send out encrypted packets on the original connection,
+  while A passes the return packets along in the clear.
+
+  There is a proposed patch for (A) here:
+      http://lists.freeswan.org/pipermail/design/2002-July/003114.html
+
+
+* Failure to look up own host name is a show stopper.
+  Solved in 1.98 and 1.98b.
+
+  Solution: new setting %dnsondemand. Usage:
+
+      leftrsasigkey=%dnsondemand   # now in sample ipsec.conf
+      rightrsasigkey=%dnsondemand.
+
+  From man ipsec.conf:
+
+      The value  %dnsondemand  means  the key is to fetched from DNS 
+      at the time it is needed.
+
+  If Linux FreeS/WAN can't get the key for your public interface from 
+  DNS, it will not keep trying, and you will not be able to do OE.
+
+  The error message is:
+
+  May 14 09:40:24 road Pluto[21210]: failure to fetch key for 193.110.157.18 
+  from DNS: failure querying DNS for KEY of 18.157.110.193.in-addr.arpa.: 
+  Host name lookup failure
+
+  Workaround: 1 or 2
+  1. Supply a key in the conn. leftrsasigkey=0s...
+  2. Fix the KEY lookup failure and try again.
+
+
+* Assertion failure at OE rekey time. Fixed in 2.0pre0. Patch for 1.98b posted 
+  at http://lists.freeswan.org/pipermail/design/2002-August/003347.html
+
+
+* 1.91 to 1.94 have serious problems with %trap and %hold bugs. These bugs, 
+  introduced while coding the support structure for OE, affect both OE and VPN 
+  connections.
+
+
+* OE may not work with reverse delegation (CNAMEs). This problem was once 
+  capable of being a show stopper.
+
+  When relying on Bind versions before 9 for local DNS services, FreeS/WAN 
+  could not follow a well constructed CNAME trail that ended in a TXT or KEY 
+  record. Although OE required both record types, in practise we noticed the 
+  problem with the more common TXT lookups, rather than the rarer KEY lookups. 
+  Bind 9 largely solves the problem, by correctly seeking TXT records in 
+  delegated reverse domains. In addition, OE between two FreeS/WAN 2.02 or 
+  later boxes no longer relies on KEY records.
+    
+  Old symptoms:
+
+  When a DNS server queried by Linux FreeS/WAN follows a CNAME, 
+  it seems to forget what record type it is looking for, and it 
+  returns a PTR, despite the fact that another record type was requested.
+
+  Workaround:
+
+  Send your provider KEY and TXT records for direct insertion into the 
+  reverse ZONE files, rather than asking your provider to delegate authority 
+  using CNAME.
+
+  People who own IP blocks, rather than leasing them, may not 
+  experience this problem. If you were assigned IPs more than 
+  five years ago, you may own your IPs.
+
+
diff --git a/doc/opportunism.nr b/doc/opportunism.nr
new file mode 100644
index 000000000..c5cae757a
--- /dev/null
+++ b/doc/opportunism.nr
@@ -0,0 +1,1115 @@
+.DA "3 May 2001"
+.ds LH "
+.ds CH "Opportunistic Encryption
+.ds RH "
+.ds LF "Draft 4+
+.ds CF "\\*(DY
+.ds RF %
+.de P
+.LP
+..
+.de R
+.LP
+\fBRationale:\fR
+..
+.de A
+.LP
+\fBAhem:\fR
+..
+.TL
+Opportunistic Encryption
+.AU
+Henry Spencer
+D. Hugh Redelmeier
+.AI
+henry@spsystems.net
+hugh@mimosa.com
+Linux FreeS/WAN Project
+.AB no
+xxx cases where reverses not controlled, all possibilities.
+xxx DHR suggests okay if gateway doesn't control reverse but destination does.
+xxx level of patience where Responder just doesn't answer the phone.
+xxx IKE finger to get basic keying info, to be confirmed via DNSSEC?
+xxx packets from some OE connections might get special status,
+if the other end is definitely someone we trust.
+Opportunistic encryption permits secure (encrypted, authenticated)
+communication via IPsec without connection-by-connection prearrangement,
+either explicitly between hosts (when the hosts are capable of it) or
+transparently via packet-intercepting security gateways.
+It uses DNS records (authenticated with DNSSEC) to provide
+the necessary information for gateway discovery and gateway authentication,
+and constrains negotiation enough to guarantee success.
+.sp
+Substantive changes since draft 3:
+write off inverse queries as a lost cause;
+use Invalid-SPI rather than Delete as notification of unknown SA;
+minor wording improvements and clarifications.
+This document takes over from the older ``Implementing Opportunistic
+Encryption'' document.
+.AE
+.NH 1
+Introduction
+.P
+A major goal of the FreeS/WAN project is opportunistic encryption:
+a (security) gateway intercepts an outgoing packet aimed at a
+remote host, and quickly attempts to negotiate an IPsec tunnel to that
+host's security gateway.
+If the attempt succeeds, traffic can then be secure,
+transparently (without changes to the host software).
+If the attempt fails,
+the packet (or a retry thereof) passes through in clear or is dropped,
+depending on local policy.
+Prearranged tunnels bypass the packet interception etc., so static VPNs
+can coexist with opportunistic encryption.
+.P
+This generalizes trivially to the end-to-end case:
+host and security gateway simply are one and the same.
+Some optimizations are possible in that case,
+but the basic scheme need not change.
+.P
+The objectives for security systems need to be explicitly stated.
+Opportunistic encryption is meant to achieve secure communication,
+without prearrangement of the individual connection
+(although some prearrangement on a per-host basis is required),
+between any two hosts which implement the protocol
+(and, if they act as security gateways,
+between hosts behind them).
+Here ``secure'' means strong encryption and authentication of packets,
+with authentication of participants\(emto prevent man-in-the-middle
+and impersonation attacks\(emdependent on several factors.
+The biggest factor is the authentication of DNS records,
+via DNSSEC or equivalent means.
+A lesser factor is which exact variant
+of the setup procedure (see section 2.2) is used,
+because there is a tradeoff between strong authentication of the other end
+and ability
+to negotiate opportunistic encryption with hosts which have limited
+or no control of their reverse-map DNS records:
+without reverse-map information,
+we can verify that the host has the right to use a particular FQDN
+(Fully Qualified Domain Name),
+but not whether that FQDN is authorized to use that IP address.
+Local policy must decide whether authentication
+or connectivity has higher priority.
+.P
+Apart from careful attention to detail in various areas,
+there are three crucial design problems for opportunistic encryption.
+It needs a way to quickly identify the remote host's security gateway.
+It needs a way to quickly obtain an authentication key for the
+security gateway.
+And the numerous options which can be specified with IKE
+must be constrained sufficiently that two independent implementations are
+guaranteed to reach agreement,
+without any explicit prearrangement or preliminary negotiation.
+The first two problems are solved using DNS,
+with DNSSEC ensuring that the data obtained is reliable;
+the third is solved by specifying a minimum standard which must be supported.
+.P
+A note on philosophy:
+we have deliberately avoided providing six different
+ways to do each job, in favor of specifying one good one.
+Choices are
+provided only when they appear to be necessary,
+or at least important.
+.P
+A note on terminology:
+to avoid constant circumlocutions,
+an ISAKMP/IKE SA, possibly recreated occasionally by rekeying,
+will be referred to as a ``keying channel'',
+and a set of IPsec SAs providing bidirectional communication between
+two IPsec hosts,
+possibly recreated occasionally by rekeying,
+will be referred to as a ``tunnel''
+(it could conceivably use transport mode in the host-to-host case,
+but we advocate using tunnel mode even there).
+The word ``connection'' is here used in a more generic sense.
+The word ``lifetime'' will be avoided in favor of ``rekeying interval'',
+since many of the connections will have useful lives far shorter
+than any reasonable rekeying interval,
+and hence the two concepts must be separated.
+.P
+A note on document structure:
+Discussions of \fIwhy\fR things were done a particular way,
+or not done a particular way,
+are broken out in paragraphs headed ``Rationale:''
+(to preserve the flow of the text, many such paragraphs are deferred
+to the ends of sections).
+Paragraphs headed ``Ahem:'' are discussions of where the problem is being
+made significantly harder by problems elsewhere,
+and how that might be corrected.
+Some meta-comments are enclosed in [].
+.R
+The motive is to get the Internet encrypted.
+That requires encryption without connection-by-connection prearrangement:
+a system must be able to
+reliably negotiate an encrypted, authenticated
+connection with a total stranger.
+While end-to-end encryption is preferable,
+doing opportunistic encryption in security gateways
+gives enormous leverage for quick deployment of this technology,
+in a world where end-host software is often primitive, rigid, and outdated.
+.R
+Speed is of the essence in tunnel setup:
+a connection-establishment delay longer than about 10 seconds
+begins to cause problems for users and applications.
+Thus the emphasis on rapidity in gateway discovery and key fetching.
+.A
+Host-to-host opportunistic encryption
+would be utterly trivial if a fast public-key
+encryption/signature
+algorithm was available.
+You would do a reverse lookup on the destination address to obtain a
+public key for that address,
+and simply encrypt all packets going to it with that key,
+signing them with your own private key.
+Alas, this is impractical with current CPU speeds and current algorithms
+(although as noted later, it might be of some use for limited purposes).
+Nevertheless, it is a useful model.
+.NH 1
+Connection Setup
+.P
+For purposes of discussion, the network is taken to look like this:
+.DS
+Source----Initiator----...----Responder----Destination
+.DE
+The intercepted packet comes from the Source,
+bound for the Destination,
+and is intercepted at the Initiator.
+The Initiator communicates over the insecure Internet to the Responder.
+The Source and the Initiator might be the same host,
+or the Source might be an end-user host and the Initiator a
+security gateway (SG).
+Likewise for the Responder and the Destination.
+.P
+Given an intercepted packet,
+whose useful information (for our purposes)
+is essentially only the Destination's IP address,
+the Initiator
+must quickly determine the Responder (the Destination's SG) and
+fetch everything needed to authenticate it.
+The Responder must do likewise for the Initiator.
+Both must eventually also confirm that the other is authorized to act
+on behalf of the client host behind it (if any).
+.P
+An important subtlety here is that if the alternative to an IPsec tunnel
+is plaintext transmission, negative results must be obtained quickly.
+That is,
+the decision that \fIno\fR tunnel can be established must also be made rapidly.
+.NH 2
+Packet Interception
+.P
+Interception of outgoing packets is relatively straightforward
+in principle.
+It is preferable to put the intercepted packet on hold rather than
+dropping it, since higher-level retries are not necessarily well-timed.
+There is a problem of hosts and applications retrying during negotiations.
+ARP implementations, which face the same problem,
+use the approach of keeping the \fImost recent\fR
+packet for an as-yet-unresolved address,
+and throwing away older ones.
+(Incrementing of request numbers etc. means that replies to older ones may no
+longer be accepted.)
+.P
+Is it worth intercepting \fIincoming\fR packets, from the outside world, and
+attempting tunnel setup based on them?
+No, unless and until a way can be devised to initiate opportunistic encryption
+to a non-opportunistic responder,
+because
+if the other end has not initiated tunnel setup itself, it will not be
+prepared to do so at our request.
+.R
+Note, however, that most incoming packets will promptly be followed by
+an outgoing packet in response!
+Conceivably it might be useful to start early stages of negotiation,
+at least as far as looking up information,
+in response to an incoming packet.
+.R
+If a plaintext incoming packet indicates that the other
+end is not prepared to do opportunistic encryption,
+it might seem that this fact should be noted, to
+avoid consuming resources and delaying
+traffic in an attempt at opportunistic setup which is doomed to fail.
+However, this would be a major security hole,
+since the plaintext packet is not authenticated;
+see section 2.5.
+.NH 2
+Algorithm
+.P
+For clarity,
+the following defers most discussion of error handling to the end.
+.nr x \w'Step 3A.'u+1n
+.de S
+.IP "Step \\$1." \nxu
+..
+.S 1
+Initiator does a DNS reverse lookup on the Destination address,
+asking not for the usual PTR records,
+but for TXT records.
+Meanwhile, Initiator also sends a ping to the Destination,
+to cause any other dynamic setup actions to start happening.
+(Ping replies are disregarded;
+the host might not be reachable with plaintext pings.)
+.S 2A
+If at least one suitable TXT record (see section 2.3) comes back,
+each contains a potential Responder's IP address
+and that Responder's public key (or where to find it).
+Initiator picks one TXT record, based on priority (see 2.3),
+thus picking a Responder.
+If there was no public key in the TXT record,
+the Initiator also starts a DNS lookup (as specified by the TXT record)
+to get KEY records.
+.S 2B
+If no suitable TXT record is available,
+and policy permits,
+Initiator designates the Destination itself as the Responder
+(see section 2.4).
+If policy does not permit,
+or the Destination is unresponsive to the negotiation,
+then opportunistic encryption is not possible,
+and Initiator gives up (see section 2.5).
+.S 3
+If there already is a keying channel to the Responder's IP address,
+the Initiator uses the existing keying channel;
+skip to step 10.
+Otherwise, the Initiator starts an IKE Phase 1 negotiation
+(see section 2.7 for details)
+with the Responder.
+The address family of the Responder's IP address dictates whether
+the keying channel and the outside of the tunnel should be IPv4 or IPv6.
+.S 4
+Responder gets the first IKE message,
+and responds.
+It also starts a DNS reverse lookup on the Initiator's IP address,
+for KEY records, on speculation.
+.S 5
+Initiator gets Responder's reply,
+and sends first message of IKE's D-H exchange (see 2.4).
+.S 6
+Responder gets Initiator's D-H message,
+and responds with a matching one.
+.S 7
+Initiator gets Responder's D-H message;
+encryption is now established, authentication remains to be done.
+Initiator sends IKE authentication message,
+with an FQDN identity if a reverse lookup on its address will not yield a
+suitable KEY record.
+(Note, an FQDN need not
+actually correspond to a host\(eme.g., the DNS data for it need not
+include an A record.)
+.S 8
+Responder gets Initiator's authentication message.
+If there is no identity included,
+Responder waits for step 4's speculative DNS lookup to finish;
+it should yield a suitable KEY record (see 2.3).
+If there is an FQDN identity,
+responder discards any data obtained from step 4's DNS lookup;
+does a forward lookup on the FQDN, for a KEY record;
+waits for that lookup to return;
+it should yield a suitable KEY record.
+Either way, Responder uses the KEY data to verify the message's hash.
+Responder replies with an authentication message,
+with an FQDN identity if a reverse lookup on its address will not yield a
+suitable KEY record.
+.S 9A
+(If step 2A was used.)
+The Initiator gets the Responder's authentication message.
+Step 2A has provided a key (from the TXT record or via DNS lookup).
+Verify message's hash.
+Encrypted and authenticated keying channel established,
+man-in-middle attack precluded.
+.S 9B
+(If step 2B was used.)
+The Initiator gets the Responder's authentication message,
+which must contain an FQDN identity (if the Responder can't put a TXT in his
+reverse map he presumably can't do a KEY either).
+Do forward lookup on the FQDN,
+get suitable KEY record, verify hash.
+Encrypted keying channel established,
+man-in-middle attack precluded,
+but authentication weak (see 2.4).
+.S 10
+Initiator initiates IKE Phase 2 negotiation (see 2.7) to establish tunnel,
+specifying Source and Destination identities as IP addresses (see 2.6).
+The address family of those addresses also determines whether the inside
+of the tunnel should be IPv4 or IPv6.
+.S 11
+Responder gets first Phase 2 message.
+Now the Responder finally knows what's going on!
+Unless the specified Source is identical to the Initiator,
+Responder initiates DNS reverse lookup on Source IP address,
+for TXT records;
+waits for result;
+gets suitable TXT record(s) (see 2.3),
+which should contain either the Initiator's IP address
+or an FQDN identity identical to that supplied by the Initiator in step 7.
+This verifies that the Initiator is authorized
+to act as SG for the Source.
+Responder replies with second Phase 2 message,
+selecting acceptable details (see 2.7),
+and establishes tunnel.
+.S 12
+Initiator gets second Phase 2 message,
+establishes tunnel (if he didn't already),
+and releases the intercepted packet into it, finally.
+.S 13
+Communication proceeds.
+See section 3 for what happens later.
+.P
+As additional information becomes available,
+notably in steps 1, 2, 4, 8, 9, 11, and 12,
+there is always a possibility that local policy
+(e.g., access limitations) might prevent further progress.
+Whenever possible,
+at least attempt to inform the other end of this.
+.P
+At any time, there is a possibility of the negotiation failing due to
+unexpected responses, e.g. the Responder not responding at all
+or rejecting all Initiator's proposals.
+If multiple SGs were found as possible Responders,
+the Initiator should try at least one more before giving up.
+The number tried should be influenced by what the alternative is:
+if the traffic will otherwise be discarded, trying the full list is
+probably appropriate,
+while if the alternative is plaintext transmission,
+it might be based on how long the tries are taking.
+The Initiator should try as many as it reasonably can,
+ideally all of them.
+.P
+There is a sticky problem with timeouts.
+If the Responder is down
+or otherwise inaccessible, in the worst case we won't hear about this
+except by not getting responses.
+Some other, more pathological or even
+evil, failure cases can have the same result.
+The problem is that in the
+case where plaintext is permitted, we want to decide whether a tunnel is
+possible quickly.
+There is no good solution to this, alas;
+we just have to take the time and do it right.
+(Passing plaintext meanwhile
+looks attractive at first glance... but exposing
+the first few seconds of a connection is often almost as bad as exposing
+the whole thing.
+Worse, if the user checks the status of the connection,
+after that brief window it looks secure!)
+.P
+The flip side of waiting for a timeout is that all other forms of
+feedback, e.g. ``host not reachable'',
+arguably should be \fIignored\fR,
+because in the absence of authenticated ICMP,
+you cannot trust them!
+.R
+An alternative, sometimes suggested, to the use of explicit DNS records
+for SG discovery is to directly attempt IKE negotiation with the
+destination host,
+and assume that any relevant SG will be on the packet path,
+will intercept the IKE packets,
+and will impersonate the destination host for the IKE negotiation.
+This is superficially attractive but is a very bad idea.
+It assumes that routing is stable throughout negotiation,
+that the SG is on the plaintext-packets path,
+and that the destination host is routable
+(yes, it is possible to have (private) DNS data for an unroutable host).
+Playing extra games in the plaintext-packet path hurts performance and
+can be expected to be unpopular.
+Various difficulties ensue when there are multiple SGs along the path
+(there is already bad experience with this, in RSVP),
+and the presence of even one can make it impossible
+to do IKE direct to the host when that is what's wanted.
+Worst of all, such impersonation breaks the IP network model badly,
+making problems difficult to diagnose and impossible to work around
+(and there is already bad experience with this, in areas like web caching).
+.R
+(Step 1.)
+Dynamic setup actions might include establishment of demand-dialed links.
+These might be present anywhere along the path,
+so one cannot rely on out-of-band communication at the Initiator to
+trigger them.
+Hence the ping.
+.R
+(Step 2.)
+In many cases, the IP address on the intercepted packet will be the
+result of a name lookup just done.
+Inverse queries, an obscure DNS feature from the distant past,
+in theory can be used to ask a DNS server to reverse that lookup,
+giving the name that produced the address.
+This is not the same as a reverse lookup,
+and the difference can matter a great deal in cases where a host
+does not control its reverse map
+(e.g., when the host's IP address is dynamically assigned).
+Unfortunately, inverse queries were never widely implemented and
+are now considered obsolete.
+Phooey.
+.A
+Support for a small subset of this admittedly-obscure feature
+would be useful.
+Unfortunately, it seems unlikely.
+.R
+(Step 3.)
+Using only IP addresses to decide whether there is already a relevant
+keying channel avoids some
+difficult problems.
+In particular, it might seem that this should be based on identities,
+but those are not known until very late in IKE Phase 1 negotiations.
+.R
+(Step 4.)
+The DNS lookup is done on speculation
+because the data will probably be useful and the lookup can be done
+in parallel with IKE activity,
+potentially speeding things up.
+.R
+(Steps 7 and 8.)
+If an SG does not control its reverse map,
+there is no way it can prove its right to use an IP address,
+but it can nevertheless supply both an identity (as an FQDN) and
+proof of its right to use that identity.
+This is somewhat better than nothing,
+and may be quite useful if the SG is representing a client host
+which \fIcan\fR prove its right to \fIits\fR IP address.
+(For example, a fixed-address subnet might live behind an SG with
+a dynamically-assigned address;
+such an SG has to be the Initiator, not the Responder,
+so the subnet's TXT records can contain FQDN identities,
+but with that restriction, this works.)
+It might sound like this would permit some man-in-the-middle attacks
+in important cases like Road Warrior,
+but the RW can still do full authentication of the home base,
+so a man in the middle cannot successfully impersonate home base,
+and the D-H exchange doesn't work unless the man in the middle
+impersonates \fIboth\fR ends.
+.R
+(Steps 7 and 8.)
+Another situation where proof of the right to use an identity can be
+very useful is when access is deliberately limited.
+While opportunistic encryption is intended as a general-purpose
+connection mechanism between strangers,
+it may well be convenient for prearranged connections to use
+the same mechanism.
+.R
+(Steps 7 and 8.)
+FQDNs as identities are avoided where possible,
+since they can involve synchronous DNS lookups.
+.R
+(Step 11.)
+Note that only here, in Phase 2,
+does the Responder actually learn who the
+Source and Destination hosts are.
+This unfortunately demands a synchronous DNS lookup to verify that the
+Initiator is authorized to represent the Source,
+unless they are one and the same.
+This and the initial TXT lookup are the only synchronous DNS lookups
+absolutely required by the algorithm,
+and they appear to be unavoidable.
+.R
+While it might seem unlikely that a refusal to cooperate from one SG
+could be remedied by trying another\(empresumably they all use the
+same policies\(emit's conceivable that one might be misconfigured.
+Preferably they should all be tried,
+but it may be necessary to set some limits on this
+if alternatives exist.
+.NH 2
+DNS Records
+.P
+Gateway discovery and key lookup are based on TXT and KEY DNS records.
+The TXT record specifies IP address or other identity of a host's SG,
+and possibly supplies its public key as well,
+while the KEY record supplies public keys not found in TXT records.
+.NH 3
+TXT
+.P
+Opportunistic-encryption SG discovery uses TXT records with the content:
+.DS
+X-IPsec-Gateway(\fInnn\fR)=\fIiii\fR\ \fIkkk\fR
+.DE
+following RFC 1464 attribute/value
+notation.
+Records which
+do not contain an ``='',
+or which do not have exactly the specified form to the left of it,
+are ignored.
+(Near misses perhaps should be reported.)
+.P
+The \fInnn\fR is an unsigned integer which will fit in 16 bits,
+specifying an MX-style preference
+(lower number = stronger preference) to
+control the order in which multiple SGs are tried.
+If there are ties, pick one,
+randomly enough that the choice will probably be different each time.
+xxx rollover.
+The preference field is not optional;
+use ``0'' if there is no meaningful preference ordering.
+.P
+The \fIiii\fR part identifies the SG.
+Normally this is a dotted-decimal IPv4 address or
+a colon-hex IPv6 address.
+The sole exception is if the SG has no fixed address (see 2.4) but
+the host(s) behind it do,
+in which case \fIiii\fR is of the form ``@fqdn'',
+where \fIfqdn\fR is the FQDN that the SG will use to
+identify itself (in step 7 of section 2.2);
+such a record cannot be used for SG discovery by an Initiator,
+but can be used for
+SG verification (step 11 of 2.2) by a Responder.
+.P
+The \fIkkk\fR part is optional.
+If it is present,
+it is an RSA-MD5 public key in base-64 notation, as in the text
+form of an RFC 2535 KEY record.
+If it is not present,
+this specifies that the public key can be found in a KEY
+record located based on the SG's identification:
+if \fIiii\fR is an IP address,
+do a reverse lookup on that address,
+else do a forward lookup on the FQDN.
+.R
+While it is unusual for a reverse lookup to go for records other than PTR
+records (or possibly CNAME records, for RFC 2317 classless delegation),
+there's no reason why it can't.
+The TXT record is a temporary stand-in
+for (we hope, someday) a new DNS record for SG identification and keying.
+Keeping the setup process fast requires minimizing the number of DNS
+lookups, hence the desire to put all the information in one place.
+.R
+The use of RFC 1464 notation avoids collisions with other uses of TXT
+records.
+The ``X-'' in the attribute name
+indicates that this format is tentative and experimental;
+this design will probably need modification after initial experiments.
+The format is chosen with an eye on eventual binary encoding.
+Note, in particular,
+that the TXT record normally contains the \fIaddress\fR of the SG,
+not (repeat, not) its name.
+Name-to-address conversion is the job of
+whatever generates the TXT record,
+which is expected to be a program, not a human\(emthis is conceptually
+a \fIbinary\fR record, temporarily using a text encoding.
+The ``@fqdn'' form of the SG identity is
+for specialized uses and is never mapped to an address.
+.A
+A DNS TXT record contains one or more character strings,
+but RFC 1035 does not describe exactly how
+a multi-string TXT record is interpreted.
+This is relevant because a string can be at most 255 characters,
+and public keys can exceed this.
+Empirically, the standard pattern is that
+each string which is
+both less than 255 characters \fIand\fR not the final string of the
+record should have a blank appended to it,
+and the strings of the record
+should then be concatenated.
+(This observation is based on how BIND 8 transforms a TXT record
+from text to DNS binary.)
+.NH 3
+KEY
+.P
+An opportunistic-encryption KEY record
+is an Authentication-permitted,
+Entity (host),
+non-Signatory,
+IPsec,
+RSA/MD5 record
+(that is, its first four bytes are 0x42000401),
+as per RFCs 2535 and 2537.
+KEY records with other \fIflags\fR, \fIprotocol\fR, or \fIalgorithm\fR
+values are ignored.
+.R
+Unfortunately, the public key has to be
+associated with the SG, not the client host behind it.
+The Responder does not know which client it is supposed to be representing,
+or which client the Initiator is representing,
+until far too late.
+.A
+Per-client keys would reduce vulnerability to key compromise,
+and simplify key changes,
+but they would require changes to IKE Phase 1, to separately identify
+the SG and its initial client(s).
+(At present, the client identities are not known to the Responder
+until IKE Phase 2.)
+While the current IKE standard does not actually specify (!) who is
+being identified by identity payloads,
+the overwhelming consensus is that they identify the SG,
+and as seen earlier,
+this has important uses.
+.NH 3
+Summary
+.P
+For reference, the minimum set of DNS records needed to make this
+all work is either:
+.IP 1. \w'1.'u+2n
+TXT in Destination reverse map, identifying Responder and providing public key.
+.IP 2.
+KEY in Initiator reverse map, providing public key.
+.IP 3.
+TXT in Source reverse map, verifying relationship to Initiator.
+.P
+or:
+.IP 1. \w'1.'u+2n
+TXT in Destination reverse map, identifying Responder.
+.IP 2.
+KEY in Responder reverse map, providing public key.
+.IP 3.
+KEY in Initiator reverse map, providing public key.
+.IP 4.
+TXT in Source reverse map, verifying relationship to Initiator.
+.P
+Slight complications ensue for dynamic addresses,
+lack of control over reverse maps, etc.
+.NH 3
+Implementation
+.P
+In the long run, we need either a tree of trust or a web of trust,
+so we can trust our DNS data.
+The obvious approach for DNS is a tree of trust,
+but there are various practical problems with running all of this
+through the root servers,
+and a web of trust is arguably more robust anyway.
+This is logically independent of opportunistic encryption,
+and a separate design proposal will be prepared.
+.P
+Interim stages of implementation of this will require a bit of thought.
+Notably, we need some way of dealing with the lack of fully signed DNSSEC
+records right away.
+Without user interaction, probably the best we can do is to
+remember the results of old fetches, compare them to the results of new
+fetches, and complain and disbelieve all of it if there's a mismatch. 
+This does mean that somebody who gets fake data into our very first fetch
+will fool us, at least for a while, but that seems an acceptable tradeoff.
+(Obviously there needs to be a way to manually flush the remembered results
+for a specific host, to permit deliberate changes.)
+.NH 2
+Responders Without Credentials
+.P
+In cases where the Destination simply does not control its
+DNS reverse-map entries,
+there is no verifiable way to determine a suitable SG.
+This does not make communication utterly impossible, though.
+.P
+Simply attempting negotiation directly with the host is a last resort.
+(An aggressive implementation might wish to attempt it in parallel,
+rather than waiting until other options are known to be unavailable.)
+In particular, in many cases involving dynamic addresses, it will work.
+It has the disadvantage of delaying the discovery that opportunistic
+encryption is entirely impossible,
+but the case seems common enough to justify the overhead.
+.P
+However, there are policy issues here either way, because
+it is possible to impersonate such a host.
+The host can supply an FQDN identity and verify its right to use that
+identity,
+but except by prearrangement,
+there is no way to verify that the FQDN is the right one for that
+IP address.
+(The data from forward lookups may be controlled by people
+who do not own the address, so it cannot be trusted.)
+The encryption is still solid, though,
+so in many cases this may be useful.
+.NH 2
+Failure of Opportunism
+.P
+When there is no way to do opportunistic encryption, a policy issue arises:
+whether to put in a bypass (which allows plaintext traffic through)
+or a block (which discards it, perhaps with notification back to the sender).
+The choice is very much a matter of local policy,
+and may depend on details such as the higher-level protocol being used.
+For example,
+an SG might well permit plaintext HTTP but forbid plaintext Telnet,
+in which case \fIboth\fR a block and a bypass would be set up if
+opportunistic encryption failed.
+.P
+A bypass/block must, in practice,
+be treated much like an IPsec tunnel.
+It should persist for a while,
+so that high-overhead processing doesn't have to be done for every packet,
+but should go away eventually to return resources.
+It may be simplest to treat it as a degenerate tunnel.
+It should have a relatively long lifetime (say 6h) to keep the frequency
+of negotiation attempts down,
+except in the case where the other SG simply did not respond to IKE packets,
+where the lifetime should be short (say 10min) because
+the other SG is presumably down and might come back up again.
+(Cases where the other SG responded to IKE with unauthenticated error
+reports like ``port unreachable'' are borderline,
+and might deserve to be treated as an intermediate case:
+while such reports cannot be trusted unreservedly,
+in the absence of any other response,
+they do give some reason to suspect that the other SG is unable or
+unwilling to participate in opportunistic encryption.)
+.P
+As noted in section 2.1, one might think that
+arrival of a plaintext incoming packet should cause a
+bypass/block to be set up for its source host:
+such a packet is almost always followed by an outgoing reply packet;
+the incoming packet is clear evidence that opportunistic encryption is
+not available at the other end;
+attempting it will waste resources and delay traffic to no good purpose.
+Unfortunately, this means that anyone out on the Internet
+who can forge a source address can prevent encrypted communication!
+Since their source addresses are not authenticated,
+plaintext packets cannot be taken as evidence of anything,
+except perhaps that communication from that host is likely to occur soon.
+.P
+There needs to be a way for local administrators to remove a bypass/block
+ahead of its normal expiry time,
+to force a retry after a problem at the other end is known to have been fixed.
+.NH 2
+Subnet Opportunism
+.P
+In principle, when the Source or Destination host belongs to a subnet
+and the corresponding SG is willing to provide tunnels to the whole subnet,
+this should be done.
+There is no extra overhead,
+and considerable potential for avoiding later overhead if
+similar communication occurs with other members of the subnet.
+Unfortunately,
+at the moment,
+opportunistic tunnels can only have degenerate subnets (single hosts)
+at their ends.
+(This does, at least, set up the keying channel,
+so that negotiations for tunnels to other hosts in the same subnets
+will be considerably faster.)
+.P
+The crucial problem is step 11 of section 2.2:
+the Responder must verify that the Initiator is authorized to represent
+the Source,
+and this is impossible for a subnet because
+there is no way to do a reverse lookup on it.
+Information in DNS
+records for a name or a single address cannot be trusted,
+because they may be controlled by people who do not control the whole subnet.
+.A
+Except in the special case of a subnet masked on a
+byte boundary (in which case RFC 1035's convention of an incomplete
+in-addr.arpa name could be used), subnet lookup would need extensions to the
+reverse-map name space, perhaps along the lines of that commonly done for
+RFC 2317 delegation.
+IPv6 already has suitable name syntax, as in RFC 2874,
+but has no specific provisions for subnet entries in its reverse maps.
+Fixing all this is is not conceptually difficult,
+but is logically independent of opportunistic encryption,
+and will be proposed separately.
+.P
+A less-troublesome problem is that the Initiator,
+in step 10 of 2.2,
+must know exactly what subnet is present on the Responder's end
+so he can propose a tunnel to it.
+This information could be included in the TXT record
+of the Destination
+(it would have to be verified with a subnet lookup,
+but that could be done in parallel with other operations).
+The Initiator presumably
+can be configured to know what subnet(s) are present on its end.
+.NH 2
+Option Settings
+.P
+IPsec and IKE have far too many useless options, and a few useful ones.
+IKE negotiation is quite simplistic, and cannot handle even simple
+discrepancies between the two SGs.
+So it is necessary to be quite specific about what should be done and
+what should be proposed,
+to guarantee interoperability without prearrangement or
+other negotiation protocols.
+.R
+The prohibition of other negotiations is simply because there is no time.
+The setup algorithm (section 2.2) is lengthy already.
+.P
+[Open question:
+should opportunistic IKE use a different port than normal IKE?]
+.P
+Somewhat arbitrarily and
+tentatively, opportunistic SGs must support Main Mode, Oakley group 5 for
+D-H, 3DES encryption and MD5 authentication for both ISAKMP and IPsec SAs,
+RSA/MD5 digital-signature authentication with keys between 2048 and 8192 bits,
+and ESP doing both encryption and authentication.
+They must do key PFS
+in Quick Mode, but not identity PFS.
+They may support IPComp, preferably using Deflate,
+but must not insist on it.
+They may support AES as an alternative to 3DES,
+but must not insist on it.
+.R
+Identity PFS essentially requires establishing
+a complete new keying channel for each new tunnel,
+but key PFS just does a new Diffie-Hellman exchange for each rekeying,
+which is relatively cheap.
+.P
+Keying channels must remain in existence at least as long as any
+tunnel created with them remains (they are not costly, and keeping
+the management path up and available simplifies various issues).
+See section 3.1 for related issues.
+Given the use of key PFS,
+frequent rekeying does not seem critical here.
+In the absence of strong reason to do otherwise,
+the Initiator should propose rekeying at 8hr-or-1MB.
+The Responder must accept any proposal which specifies
+a rekeying time between 1hr and 24hr inclusive
+and a rekeying volume between 100KB and 10MB inclusive.
+.P
+Given the short expected useful life of most tunnels (see section 3.1),
+very few of them will survive long enough to be rekeyed.
+In the absence of strong reason to do otherwise,
+the Initiator should propose rekeying at 1hr-or-100MB.
+The Responder must accept any proposal which specifies
+a rekeying time between 10min and 8hr inclusive
+and a rekeying volume between 1MB and 1000MB inclusive.
+.P
+It is highly desirable to add some random jitter
+to the times of actual rekeying attempts,
+to break up ``convoys'' of rekeying events;
+this and certain other aspects of robust rekeying practice will be the subject
+of a separate design proposal.
+.R
+The numbers used here for rekeying intervals are chosen quite arbitrarily
+and should be re-assessed after some implementation experience is gathered.
+.NH 1
+Renewal and Teardown
+.NH 2
+Aging
+.P
+When to tear tunnels down is a bit problematic, but if we're setting up a
+potentially unbounded number of them,
+we have to tear them down \fIsomehow sometime\fR.
+.P
+Set a short initial tentative lifespan, say 1min,
+since most net flows in fact last only a few seconds.
+When that expires, look to see if
+the tunnel is still in use (definition:
+has had traffic, in either direction,
+in the last half of the tentative lifespan).
+If so, assign it a somewhat longer tentative lifespan, say 20min,
+after which, look again.
+If not, close it down.
+(This tentative lifespan is
+independent of rekeying; it is just the time when the tunnel's future
+is next considered.
+This should happen reasonably frequently, unlike
+rekeying, which is costly and shouldn't be too frequent.)
+Multi-step backoff algorithms are not worth the trouble; looking every
+20min doesn't seem onerous.
+.P
+If the security gateway and the client host are one and the same,
+tunnel teardown decisions might wish to pay attention to TCP connection status,
+as reported by the local TCP layer.
+A still-open
+TCP connection is almost a guarantee that more traffic is coming, while
+the demise of the only TCP connection through a tunnel is a strong hint
+that none is.
+If the SG and the client host are separate machines,
+though, tracking TCP connection status requires packet snooping,
+which is complicated and probably not worthwhile.
+.P
+IKE keying channels likewise are torn down when it appears the need has
+passed.
+They always linger longer than the last tunnel they administer,
+in case they are needed again; the cost of retaining them is low.
+Other than that,
+unless the number of keying channels on the SG gets large,
+the SG should simply retain all of them until rekeying time,
+since rekeying is the only costly event.
+When about to rekey a keying channel which has no current tunnels,
+note when the last actual keying-channel traffic occurred,
+and close the keying channel down if it wasn't in the last, say, 30min.
+When rekeying a keying channel (or perhaps shortly before rekeying is expected),
+Initiator and Responder should re-fetch the public keys used for
+SG authentication,
+against the possibility that they have changed or disappeared.
+.P
+See section 2.7 for discussion of rekeying intervals.
+.P
+Given the low user impact of tearing down and rebuilding a connection
+(a tunnel or a keying channel),
+rekeying attempts should not be too persistent:
+one can always just rebuild when needed,
+so heroic efforts to preserve an existing connection are unnecessary.
+Say, try every 10s for a minute and every minute for 5min,
+and then give up and declare the connection
+(and all other connections to that IKE peer) dead.
+.R
+In future, more sophisticated, versions of this protocol,
+examining the initial packet might permit a more intelligent guess at
+the tunnel's useful life.
+HTTP connections in particular are
+notoriously bursty and repetitive.
+.R
+Note that rekeying a keying connection basically consists of building a
+new keying connection from scratch,
+using IKE Phase 1,
+and abandoning the old one.
+.NH 2
+Teardown and Cleanup
+.P
+Teardown should always be coordinated with the other end.
+This means interpreting and sending Delete notifications.
+.P
+On receiving a Delete for the outbound SAs of a tunnel
+(or some subset of them),
+tear down the inbound ones too, and notify the other end
+with a Delete.
+Tunnels need to be considered as bidirectional entities,
+even though the low-level protocols don't think of them that way.
+.P
+When the deletion is initiated locally,
+rather than as a response to a received Delete,
+send a Delete for (all) the inbound SAs of a tunnel.
+If no responding Delete is received for the outbound SAs,
+try re-sending the original Delete.
+Three tries spaced 10s apart seems a reasonable level of effort.
+(Indefinite persistence is not necessary;
+whether the other end isn't cooperating because it doesn't feel like
+it, or because it is down/disconnected/etc.,
+the problem will eventually be cleared up by other means.)
+.P
+After rekeying,
+transmission should switch to using the new SAs (ISAKMP or IPsec)
+immediately,
+and the old leftover SAs should be cleared out promptly
+(and Deletes sent) rather than waiting for them to expire.
+This reduces clutter and minimizes confusion.
+.P
+Since there is only one keying channel per remote IP address,
+the question of whether a Delete notification has appeared on a
+``suitable'' keying channel does not arise.
+.R
+The pairing of Delete notifications effectively constitutes an
+acknowledged Delete, which is highly desirable.
+.NH 2
+Outages and Reboots
+.P
+Tunnels sometimes go down because the other
+end crashes, or disconnects, or has a network link break,
+and there is no notice of this in the general case.
+(Even in the event of a crash and
+successful reboot, other SGs don't hear about it unless the
+rebooted SG has specific reason to talk to them immediately.)
+Over-quick response to temporary network outages is undesirable...
+but note that a tunnel can be torn
+down and then re-established without any user-visible effect except
+a pause in traffic,
+whereas if one end does reboot,
+the other end can't get packets to it \fIat all\fR (except via IKE)
+until the situation is noticed.
+So a bias toward quick response is appropriate,
+even at the cost of occasional false alarms.
+.P
+Heartbeat mechanisms are somewhat unsatisfactory for this.
+Unless they are very frequent, which causes other problems,
+they do not detect the problem promptly.
+.A
+What is really wanted is authenticated ICMP.
+This might be a case where public-key encryption/authentication
+of network packets is the right thing to do,
+despite the expense.
+.P
+In the absence of that, a two-part approach seems warranted.
+.P
+First,
+when an SG receives an IPsec packet that is addressed to it,
+and otherwise appears healthy,
+but specifies an unknown SA and is from a host that the receiver currently
+has no keying channel to,
+the receiver must attempt to inform the sender
+via an IKE Initial-Contact notification
+(necessarily sent in plaintext,
+since there is no suitable keying channel).
+This must be severely rate-limited on \fIboth\fR ends;
+one notification per SG pair per minute seems ample.
+.P
+Second, there is an obvious difficulty with this:
+the Initial-Contact notification is unauthenticated
+and cannot be trusted.
+So it must be taken as a hint only:
+there must be a way to confirm it.
+.P
+What is needed here is something that's desirable for
+debugging and testing anyway:
+an IKE-level ping mechanism.
+Pinging direct at the IP level instead will not tell us about a
+crash/reboot event.
+Sending pings through tunnels has
+various complications (they should stop at the far mouth of the tunnel
+instead of going on to a subnet; they should not count against idle
+timers; etc.).
+What is needed is a continuity check on a keying channel.
+(This could also be used as a heartbeat,
+should that seem useful.)
+.P
+IKE Ping delivery need not be reliable, since the whole point of a ping is
+simply to provoke an acknowledgement.
+They should preferably be authenticated,
+but it is not clear that this is absolutely necessary,
+although if they are not they need
+encryption plus a timestamp or a nonce,
+to foil replay mischief.
+How they are implemented is a secondary issue,
+and a separate design proposal will be prepared.
+.A
+Some existing implementations are already using
+(private) notify value 30000 (``LIKE_HELLO'') as ping
+and (private) notify value 30002 (``SHUT_UP'') as ping reply.
+.P
+If an IKE Ping gets no response, try some (say 8) IP pings,
+spaced a few seconds apart, to check IP connectivity;
+if one comes back, try another IKE Ping;
+if that gets no response,
+the other end probably has rebooted, or otherwise been re-initialized,
+and its tunnels and keying channel(s) should be torn down.
+.P
+In a similar vein,
+giving limited rekeying persistence,
+a short network outage could take some tunnels down without
+disrupting others.
+On receiving a packet for an unknown SA from a host that a keying
+channel is currently open to,
+send that host a Invalid-SPI notification for that SA.
+xxx that's not what Invalid-SPI is for.
+The other host can then tear down the half-torn-down tunnel,
+and negotiate a new tunnel for the traffic
+it presumably still wants to send.
+.P
+Finally,
+it would be helpful if SGs made some attempt to deal intelligently
+with crashes and reboots.
+A deliberate shutdown should include an attempt to notify all other SGs
+currently connected by keying channels,
+using Deletes,
+that communication is about to fail.
+(Again, these will be taken as teardowns;
+attempts by the other SGs to negotiate new tunnels as replacements
+should be ignored at this point.)
+And when possible, SGs should attempt to preserve information
+about currently-connected SGs in non-volatile storage, 
+so that after a crash,
+an Initial-Contact can be sent to previous partners to
+indicate loss of all previously-established connections.
+.NH 1
+Conclusions
+.P
+This design appears to achieve the objective of setting up encryption
+with strangers.
+The authentication aspects also seem adequately addressed if the
+destination controls its reverse-map DNS entries
+and the DNS data itself can be reliably authenticated
+as having originated from the legitimate administrators of that
+subnet/FQDN.
+The authentication situation is less satisfactory when DNS is less helpful,
+but it is difficult to see what else could be done about it.
+.NH 1
+References
+.P
+[TBW]
+.NH 1
+Appendix:  Separate Design Proposals TBW
+.IP \(bu \w'\(bu'u+2n
+How can we build a web of trust with DNSSEC?
+(See section 2.3.4.)
+.IP \(bu
+How can we extend DNS reverse lookups to permit reverse lookup
+on a subnet?
+(Both address and mask must appear in the name to be looked up.)
+(See section 2.6.)
+.IP \(bu
+How can rekeying be done as robustly as possible?
+(At least partly, this is just documenting current FreeS/WAN practice.)
+(See section 2.7.)
+.IP \(bu
+How should IKE Pings be implemented?
+(See section 3.3.)
diff --git a/doc/performance.html b/doc/performance.html
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
+H5 { font-family: sans-serif }
+H6 { font-family: sans-serif }
+SUB { font-size: smaller }
+SUP { font-size: smaller }
+PRE { font-family: monospace }
+--></STYLE>
+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="interop.html">Previous</A>
+<A HREF="testing.html">Next</A>
+<HR>
+<H1><A name="performance">Performance of FreeS/WAN</A></H1>
+ The performance of FreeS/WAN is adequate for most applications.
+<P>In normal operation, the main concern is the overhead for encryption,
+ decryption and authentication of the actual IPsec (<A href="glossary.html#ESP">
+ESP</A> and/or<A href="glossary.html#AH"> AH</A>) data packets. Tunnel
+ setup and rekeying occur so much less frequently than packet processing
+ that, in general, their overheads are not worth worrying about.</P>
+<P>At startup, however, tunnel setup overheads may be significant. If
+ you reboot a gateway and it needs to establish many tunnels, expect
+ some delay. This and other issues for large gateways are discussed<A href="#biggate">
+ below</A>.</P>
+<H2><A name="pub.bench">Published material</A></H2>
+<P>The University of Wales at Aberystwyth has done quite detailed speed
+ tests and put<A href="http://tsc.llwybr.org.uk/public/reports/SWANTIME/">
+ their results</A> on the web.</P>
+<P>Davide Cerri's<A href="http://www.linux.it/~davide/doc/"> thesis (in
+ Italian)</A> includes performance results for FreeS/WAN and for<A href="glossary.html#TLS">
+ TLS</A>. He posted an<A href="http://lists.freeswan.org/pipermail/users/2001-December/006303.html">
+ English summary</A> on the mailing list.</P>
+<P>Steve Bellovin used one of AT&amp;T Research's FreeS/WAN gateways as his
+ data source for an analysis of the cache sizes required for key
+ swapping in IPsec. Available as<A href="http://www.research.att.com/~smb/talks/key-agility.email.txt">
+ text</A> or<A href="http://www.research.att.com/~smb/talks/key-agility.pdf">
+ PDF slides</A> for a talk on the topic.</P>
+<P>See also the NAI work mentioned in the next section.</P>
+<H2><A name="perf.estimate">Estimating CPU overheads</A></H2>
+<P>We can come up with a formula that roughly relates CPU speed to the
+ rate of IPsec processing possible. It is far from exact, but should be
+ usable as a first approximation.</P>
+<P>An analysis of authentication overheads for high-speed networks,
+ including some tests using FreeS/WAN, is on the<A href="http://www.pgp.com/research/nailabs/cryptographic/adaptive-cryptographic.asp">
+ NAI Labs site</A>. In particular, see figure 3 in this<A href="http://download.nai.com/products/media/pgp/pdf/acsa_final_report.pdf">
+ PDF document</A>. Their estimates of overheads, measured in Pentium II
+ cycles per byte processed are:</P>
+<TABLE align="center" border="1"><TBODY></TBODY>
+<TR><TH></TH><TH>IPsec</TH><TH>authentication</TH><TH>encryption</TH><TH>
+cycles/byte</TH></TR>
+<TR><TD>Linux IP stack alone</TD><TD>no</TD><TD>no</TD><TD>no</TD><TD align="right">
+5</TD></TR>
+<TR><TD>IPsec without crypto</TD><TD>yes</TD><TD>no</TD><TD>no</TD><TD align="right">
+11</TD></TR>
+<TR><TD>IPsec, authentication only</TD><TD>yes</TD><TD>SHA-1</TD><TD>no</TD><TD
+align="right">24</TD></TR>
+<TR><TD>IPsec with encryption</TD><TD>yes</TD><TD>yes</TD><TD>yes</TD><TD
+align="right">not tested</TD></TR>
+</TABLE>
+<P>Overheads for IPsec with encryption were not tested in the NAI work,
+ but Antoon Bosselaers'<A href="http://www.esat.kuleuven.ac.be/~bosselae/fast.html">
+ web page</A> gives cost for his optimised Triple DES implementation as
+ 928 Pentium cycles per block, or 116 per byte. Adding that to the 24
+ above, we get 140 cycles per byte for IPsec with encryption.</P>
+<P>At 140 cycles per byte, a 140 MHz machine can handle a megabyte -- 8
+ megabits -- per second. Speeds for other machines will be proportional
+ to this. To saturate a link with capacity C megabits per second, you
+ need a machine running at<VAR> C * 140/8 = C * 17.5</VAR> MHz.</P>
+<P>However, that estimate is not precise. It ignores the differences
+ between:</P>
+<UL>
+<LI>NAI's test packets and real traffic</LI>
+<LI>NAI's Pentium II cycles, Bosselaers' Pentium cycles, and your
+ machine's cycles</LI>
+<LI>different 3DES implementations</LI>
+<LI>SHA-1 and MD5</LI>
+</UL>
+<P>and does not account for some overheads you will almost certainly
+ have:</P>
+<UL>
+<LI>communication on the client-side interface</LI>
+<LI>switching between multiple tunnels -- re-keying, cache reloading and
+ so on</LI>
+</UL>
+<P>so we suggest using<VAR> C * 25</VAR> to get an estimate with a bit
+ of a built-in safety factor.</P>
+<P>This covers only IP and IPsec processing. If you have other loads on
+ your gateway -- for example if it is also working as a firewall -- then
+ you will need to add your own safety factor atop that.</P>
+<P>This estimate matches empirical data reasonably well. For example,
+ Metheringham's tests, described<A href="#klips.bench"> below</A>, show
+ a 733 topping out between 32 and 36 Mbit/second, pushing data as fast
+ as it can down a 100 Mbit link. Our formula suggests you need at least
+ an 800 to handle a fully loaded 32 Mbit link. The two results are
+ consistent.</P>
+<P>Some examples using this estimation method:</P>
+<TABLE align="center" border="1"><TBODY></TBODY>
+<TR><TH colspan="2">Interface</TH><TH colspan="3">Machine speed in MHz</TH>
+</TR>
+<TR><TH>Type</TH><TH>Mbit per
+<BR> second</TH><TH>Estimate
+<BR> Mbit*25</TH><TH>Minimum IPSEC gateway</TH><TH>Minimum with other
+ load
+<P>(e.g. firewall)</P>
+</TH></TR>
+<TR><TD>DSL</TD><TD align="right">1</TD><TD align="right">25 MHz</TD><TD rowspan="2">
+whatever you have</TD><TD rowspan="2">133, or better if you have it</TD></TR>
+<TR><TD>cable modem</TD><TD align="right">3</TD><TD align="right">75 MHz</TD>
+</TR>
+<TR><TD><STRONG>any link, light load</STRONG></TD><TD align="right"><STRONG>
+5</STRONG></TD><TD align="right">125 MHz</TD><TD>133</TD><TD>200+,<STRONG>
+ almost any surplus machine</STRONG></TD></TR>
+<TR><TD>Ethernet</TD><TD align="right">10</TD><TD align="right">250 MHz</TD><TD>
+surplus 266 or 300</TD><TD>500+</TD></TR>
+<TR><TD><STRONG>fast link, moderate load</STRONG></TD><TD align="right"><STRONG>
+20</STRONG></TD><TD align="right">500 MHz</TD><TD>500</TD><TD>800+,<STRONG>
+ any current off-the-shelf PC</STRONG></TD></TR>
+<TR><TD>T3 or E3</TD><TD align="right">45</TD><TD align="right">1125 MHz</TD><TD>
+1200</TD><TD>1500+</TD></TR>
+<TR><TD>fast Ethernet</TD><TD align="right">100</TD><TD align="right">
+2500 MHz</TD><TD align="center" colspan="2" rowspan="2">// not feasible
+ with 3DES in software on current machines //</TD></TR>
+<TR><TD>OC3</TD><TD align="right">155</TD><TD align="right">3875 MHz</TD>
+</TR>
+</TABLE>
+<P>Such an estimate is far from exact, but should be usable as minimum
+ requirement for planning. The key observations are:</P>
+<UL>
+<LI>older<STRONG> surplus machines</STRONG> are fine for IPsec gateways
+ at loads up to<STRONG> 5 megabits per second</STRONG> or so</LI>
+<LI>a<STRONG> mid-range new machine</STRONG> can handle IPsec at rates
+ up to<STRONG> 20 megabits per second</STRONG> or more</LI>
+</UL>
+<H3><A name="perf.more">Higher performance alternatives</A></H3>
+<P><A href="glossary.html#AES">AES</A> is a new US government block
+ cipher standard, designed to replace the obsolete<A href="glossary.html#DES">
+ DES</A>. If FreeS/WAN using<A href="glossary.html#3DES"> 3DES</A> is
+ not fast enough for your application, the AES<A href="web.html#patch">
+ patch</A> may help.</P>
+<P>To date (March 2002) we have had only one<A href="http://lists.freeswan.org/pipermail/users/2002-February/007771.html">
+ mailing list report</A> of measurements with the patch applied. It
+ indicates that, at least for the tested load on that user's network,<STRONG>
+ AES roughly doubles IPsec throughput</STRONG>. If further testing
+ confirms this, it may prove possible to saturate an OC3 link in
+ software on a high-end box.</P>
+<P>Also, some work is being done toward support of<A href="compat.html#hardware">
+ hardware IPsec acceleration</A> which might extend the range of
+ requirements FreeS/WAN could meet.</P>
+<H3><A NAME="11_2_2">Other considerations</A></H3>
+<P>CPU speed may be the main issue for IPsec performance, but of course
+ it isn't the only one.</P>
+<P>You need good ethernet cards or other network interface hardware to
+ get the best performance. See this<A href="http://www.ethermanage.com/ethernet/ethernet.html">
+ ethernet information</A> page and this<A href="http://www.scyld.com/diag">
+ Linux network driver</A> page.</P>
+<P>The current FreeS/WAN kernel code is largely single-threaded. It is
+ SMP safe, and will run just fine on a multiprocessor machine (<A href="compat.html#multiprocessor">
+discussion</A>), but the load within the kernel is not shared
+ effectively. This means that, for example to saturate a T3 -- which
+ needs about a 1200 MHz machine -- you cannot expect something like a
+ dual 800 to do the job.</P>
+<P>On the other hand, SMP machines do tend to share loads well so --
+ provided one CPU is fast enough for the IPsec work -- a multiprocessor
+ machine may be ideal for a gateway with a mixed load.</P>
+<H2><A name="biggate">Many tunnels from a single gateway</A></H2>
+<P>FreeS/WAN allows a single gateway machine to build tunnels to many
+ others. There may, however, be some problems for large numbers as
+ indicated in this message from the mailing list:</P>
+<PRE>Subject: Re: Maximum number of ipsec tunnels?
+   Date: Tue, 18 Apr 2000
+   From: &quot;John S. Denker&quot; &lt;jsd@research.att.com&gt;
+
+Christopher Ferris wrote:
+
+&gt;&gt; What are the maximum number ipsec tunnels FreeS/WAN can handle??
+
+Henry Spencer wrote:
+
+&gt;There is no particular limit.  Some of the setup procedures currently
+&gt;scale poorly to large numbers of connections, but there are (clumsy)
+&gt;workarounds for that now, and proper fixes are coming.
+
+1) &quot;Large&quot; numbers means anything over 50 or so.  I routinely run boxes
+with about 200 tunnels.  Once you get more than 50 or so, you need to worry
+about several scalability issues:
+
+a) You need to put a &quot;-&quot; sign in syslogd.conf, and rotate the logs daily
+not weekly.
+
+b) Processor load per tunnel is small unless the tunnel is not up, in which
+case a new half-key gets generated every 90 seconds, which can add up if
+you've got a lot of down tunnels.
+
+c) There's other bits of lore you need when running a large number of
+tunnels.  For instance, systematically keeping the .conf file free of
+conflicts requires tools that aren't shipped with the standard freeswan
+package.
+
+d) The pluto startup behavior is quadratic.  With 200 tunnels, this eats up
+several minutes at every restart.   I'm told fixes are coming soon.
+
+2) Other than item (1b), the CPU load depends mainly on the size of the
+pipe attached, not on the number of tunnels.
+</PRE>
+<P>It is worth noting that item (1b) applies only to repeated attempts
+ to re-key a data connection (IPsec SA, Phase 2) over an established
+ keying connection (ISAKMP SA, Phase 1). There are two ways to reduce
+ this overhead using settings in<A href="manpage.d/ipsec.conf.5.html">
+ ipsec.conf(5)</A>:</P>
+<UL>
+<LI>set<VAR> keyingtries</VAR> to some small value to limit repetitions</LI>
+<LI>set<VAR> keylife</VAR> to a short time so that a failing data
+ connection will be cleaned up when the keying connection is reset.</LI>
+</UL>
+<P>The overheads for establishing keying connections (ISAKMP SAs, Phase
+ 1) are lower because for these Pluto does not perform expensive
+ operations before receiving a reply from the peer.</P>
+<P>A gateway that does a lot of rekeying -- many tunnels and/or low
+ settings for tunnel lifetimes -- will also need a lot of<A href="glossary.html#random">
+ random numbers</A> from the random(4) driver.</P>
+<H2><A name="low-end">Low-end systems</A></H2>
+<P><EM>Even a 486 can handle a T1 line</EM>, according to this mailing
+ list message:</P>
+<PRE>Subject: Re: linux-ipsec: IPSec Masquerade
+   Date: Fri, 15 Jan 1999 11:13:22 -0500
+   From: Michael Richardson 
+
+. . . A 486/66 has been clocked by Phil Karn to do
+10Mb/s encryption.. that uses all the CPU, so half that to get some CPU,
+and you have 5Mb/s. 1/3 that for 3DES and you get 1.6Mb/s....</PRE>
+<P>and a piece of mail from project technical lead Henry Spencer:</P>
+<PRE>Oh yes, and a new timing point for Sandy's docs...  A P60 -- yes, a 60MHz
+Pentium, talk about antiques -- running a host-to-host tunnel to another
+machine shows an FTP throughput (that is, end-to-end results with a real
+protocol) of slightly over 5Mbit/s either way.  (The other machine is much
+faster, the network is 100Mbps, and the ether cards are good ones... so
+the P60 is pretty definitely the bottleneck.)</PRE>
+<P>From the above, and from general user experience as reported on the
+ list, it seems clear that a cheap surplus machine -- a reasonable 486,
+ a minimal Pentium box, a Sparc 5, ... -- can easily handle a home
+ office or a small company connection using any of:</P>
+<UL>
+<LI>ADSL service</LI>
+<LI>cable modem</LI>
+<LI>T1</LI>
+<LI>E1</LI>
+</UL>
+<P>If available, we suggest using a Pentium 133 or better. This should
+ ensure that, even under maximum load, IPsec will use less than half the
+ CPU cycles. You then have enough left for other things you may want on
+ your gateway -- firewalling, web caching, DNS and such.</P>
+<H2><A name="klips.bench">Measuring KLIPS</A></H2>
+<P>Here is some additional data from the mailing list.</P>
+<PRE>Subject: FreeSWAN (specically KLIPS) performance measurements
+   Date: Thu, 01 Feb 2001
+   From: Nigel Metheringham &lt;Nigel.Metheringham@intechnology.co.uk&gt;
+
+I've spent a happy morning attempting performance tests against KLIPS 
+(this is due to me not being able to work out the CPU usage of KLIPS so 
+resorting to the crude measurements of maximum throughput to give a 
+baseline to work out loading of a box).
+
+Measurements were done using a set of 4 boxes arranged in a line, each 
+connected to the next by 100Mbit duplex ethernet.  The inner 2 had an 
+ipsec tunnel between them (shared secret, but I was doing measurements 
+when the tunnel was up and running - keying should not be an issue 
+here).  The outer pair of boxes were traffic generators or traffic sink.
+
+The crypt boxes are Compaq DL380s - Uniprocessor PIII/733 with 256K 
+cache.  They have 128M main memory.  Nothing significant was running on 
+the boxes other than freeswan.  The kernel was a 2.2.19pre7 patched 
+with freeswan and ext3.
+
+Without an ipsec tunnel in the chain (ie the 2 inner boxes just being 
+100BaseT routers), throughput (measured with ttcp) was between 10644 
+and 11320 KB/sec
+
+With an ipsec tunnel in place, throughput was between 3268 and 3402 
+KB/sec
+
+These measurements are for data pushed across a TCP link, so the 
+traffic on the wire between the 2 ipsec boxes would have been higher 
+than this....
+
+vmstat (run during some other tests, so not affecting those figures) on 
+the encrypting box shows approx 50% system &amp; 50% idle CPU - which I 
+don't believe at all.  Interactive feel of the box was significantly 
+sluggish.
+
+I also tried running the kernel profiler (see man readprofile) during 
+test runs.
+
+A box doing primarily decrypt work showed basically nothing happening - 
+I assume interrupts were off.
+A box doing encrypt work showed the following:-
+ Ticks Function                                   Load
+ ~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~    ~~~~~~
+   956 total                                      0.0010
+   532 des_encrypt2                               0.1330
+   110 MD5Transform                               0.0443
+    97 kmalloc                                    0.1880
+    39 des_encrypt3                               0.1336
+    23 speedo_interrupt                           0.0298
+    14 skb_copy_expand                            0.0250
+    13 ipsec_tunnel_start_xmit                    0.0009
+    13 Decode                                     0.1625
+    11 handle_IRQ_event                           0.1019
+    11 .des_ncbc_encrypt_end                      0.0229
+    10 speedo_start_xmit                          0.0188
+     9 satoa                                      0.0225
+     8 kfree                                      0.0118
+     8 ip_fragment                                0.0121
+     7 ultoa                                      0.0365
+     5 speedo_rx                                  0.0071
+     5 .des_encrypt2_end                          5.0000
+     4 _stext                                     0.0140
+     4 ip_fw_check                                0.0035
+     2 rj_match                                   0.0034
+     2 ipfw_output_check                          0.0200
+     2 inet_addr_type                             0.0156
+     2 eth_copy_and_sum                           0.0139
+     2 dev_get                                    0.0294
+     2 addrtoa                                    0.0143
+     1 speedo_tx_buffer_gc                        0.0024
+     1 speedo_refill_rx_buf                       0.0022
+     1 restore_all                                0.0667
+     1 number                                     0.0020
+     1 net_bh                                     0.0021
+     1 neigh_connected_output                     0.0076
+     1 MD5Final                                   0.0083
+     1 kmem_cache_free                            0.0016
+     1 kmem_cache_alloc                           0.0022
+     1 __kfree_skb                                0.0060
+     1 ipsec_rcv                                  0.0001
+     1 ip_rcv                                     0.0014
+     1 ip_options_fragment                        0.0071
+     1 ip_local_deliver                           0.0023
+     1 ipfw_forward_check                         0.0139
+     1 ip_forward                                 0.0011
+     1 eth_header                                 0.0040
+     1 .des_encrypt3_end                          0.0833
+     1 des_decrypt3                               0.0034
+     1 csum_partial_copy_generic                  0.0045
+     1 call_out_firewall                          0.0125
+
+Hope this data is helpful to someone... however the lack of visibility 
+into the decrypt side makes things less clear</PRE>
+<H2><A name="speed.compress">Speed with compression</A></H2>
+<P>Another user reported some results for connections with and without
+ IP compression:</P>
+<PRE>Subject: [Users] Speed with compression
+   Date: Fri, 29 Jun 2001
+   From: John McMonagle &lt;johnm@advocap.org&gt;
+
+Did a couple tests with compression using the new 1.91 freeswan.
+
+Running between 2 sites with cable modems.  Both  using approximately
+130 mhz pentium.
+
+Transferred files with ncftp.
+
+Compressed file was a 6mb compressed  installation file.
+Non compressed was 18mb /var/lib/rpm/packages.rpm
+
+                            Compressed vpn          regular vpn
+Compress file                42.59 kBs               42.08 kBs
+regular file                110.84 kBs               41.66 kBs
+
+Load  was about 0 either way.
+Ping times were very similar  a bit above 9 ms.
+
+Compression looks attractive to me.</PRE>
+ Later in the same thread, project technical lead Henry Spencer added:
+<PRE>&gt; is there a reason not to switch compression on?  I have large gateway boxes
+&gt; connecting 3 connections, one of them with a measly DS1 link...
+
+Run some timing tests with and without, with data and loads representative
+of what you expect in production.  That's the definitive way to decide. 
+If compression is a net loss, then obviously, leave it turned off.  If it
+doesn't make much difference, leave it off for simplicity and hence
+robustness.  If there's a substantial gain, by all means turn it on. 
+
+If both ends support compression and can successfully negotiate a
+compressed connection (trivially true if both are FreeS/WAN 1.91), then
+the crucial question is CPU cycles. 
+
+Compression has some overhead, so one question is whether *your* data
+compresses well enough to save you more CPU cycles (by reducing the volume
+of data going through CPU-intensive encryption/decryption) than it costs
+you.  Last time I ran such tests on data that was reasonably compressible
+but not deliberately contrived to be so, this generally was not true --
+compression cost extra CPU cycles -- so compression was worthwhile only if
+the link, not the CPU, was the bottleneck.  However, that was before the
+slow-compression bug was fixed.  I haven't had a chance to re-run those
+tests yet, but it sounds like I'd probably see a different result. </PRE>
+ The bug he refers to was a problem with the compression libraries that
+ had us using C code, rather than assembler, for compression. It was
+ fixed before 1.91.
+<H2><A name="methods">Methods of measuring</A></H2>
+<P>If you want to measure the loads FreeS/WAN puts on a system, note
+ that tools such as top or measurements such as load average are
+ more-or-less useless for this. They are not designed to measure
+ something that does most of its work inside the kernel.</P>
+<P>Here is a message from FreeS/WAN kernel programmer Richard Guy Briggs
+ on this:</P>
+<PRE>&gt; I have a batch of boxes doing Freeswan stuff.
+&gt; I want to measure the CPU loading of the Freeswan tunnels, but am 
+&gt; having trouble seeing how I get some figures out...
+&gt; 
+&gt;  - Keying etc is in userspace so will show up on the per-process
+&gt;    and load average etc (ie pluto's load)
+
+Correct.
+
+&gt;  - KLIPS is in the kernel space, and does not show up in load average
+&gt;    I think also that the KLIPS per-packet processing stuff is running
+&gt;    as part of an interrupt handler so it does not show up in the
+&gt;    /proc/stat system_cpu or even idle_cpu figures
+
+It is not running in interrupt handler.  It is in the bottom half.
+This is somewhere between user context (careful, this is not
+userspace!) and hardware interrupt context.
+
+&gt; Is this correct, and is there any means of instrumenting how much the 
+&gt; cpu is being loaded - I don't like the idea of a system running out of 
+&gt; steam whilst still showing 100% idle CPU :-)
+
+vmstat seems to do a fairly good job, but use a running tally to get a
+good idea.  A one-off call to vmstat gives different numbers than a
+running stat.  To do this, put an interval on your vmstat command
+line.</PRE>
+ and another suggestion from the same thread:
+<PRE>Subject: Re: Measuring the CPU usage of Freeswan
+   Date: Mon, 29 Jan 2001
+   From: Patrick Michael Kane &lt;modus@pr.es.to&gt;
+ 
+The only truly accurate way to accurately track FreeSWAN CPU usage is to use
+a CPU soaker. You run it on an unloaded system as a benchmark, then start up
+FreeSWAN and take the difference to determine how much FreeSWAN is eating.
+I believe someone has done this in the past, so you may find something in
+the FreeSWAN archives.  If not, someone recently posted a URL to a CPU
+soaker benchmark tool on linux-kernel.</PRE>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="interop.html">Previous</A>
+<A HREF="testing.html">Next</A>
+</BODY>
+</HTML>
diff --git a/doc/policygroups.html b/doc/policygroups.html
new file mode 100644
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
+H5 { font-family: sans-serif }
+H6 { font-family: sans-serif }
+SUB { font-size: smaller }
+SUP { font-size: smaller }
+PRE { font-family: monospace }
+--></STYLE>
+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="quickstart.html">Previous</A>
+<A HREF="faq.html">Next</A>
+<HR>
+<H1><A NAME="4">How to Configure Linux FreeS/WAN with Policy Groups</A></H1>
+<A NAME="policygroups"></A>
+<H2><A NAME="4_1">What are Policy Groups?</A></H2>
+<P><STRONG>Policy Groups</STRONG> are an elegant general mechanism to
+ configure FreeS/WAN. They are useful for many FreeS/WAN users.</P>
+<P>In previous FreeS/WAN versions, you needed to configure each IPsec
+ connection explicitly, on both local and remote hosts. This could
+ become complex.</P>
+<P>By contrast, Policy Groups allow you to set local IPsec policy for
+ lists of remote hosts and networks, simply by listing the hosts and
+ networks which you wish to have special treatment in one of several
+ Policy Group files. FreeS/WAN then internally creates the connections
+ needed to implement each policy.</P>
+<P>In the next section we describe our five Base Policy Groups, which
+ you can use to configure IPsec in many useful ways. Later, we will show
+ you how to create an IPsec VPN using one line of configuration for each
+ remote host or network.</P>
+<A NAME="builtin_policygroups"></A>
+<H3><A NAME="4_1_1">Built-In Security Options</A></H3>
+<P>FreeS/WAN offers these Base Policy Groups:</P>
+<DL>
+<DT>private</DT>
+<DD> FreeS/WAN only communicates privately with the listed<A HREF="glossary.html#CIDR">
+ CIDR</A> blocks. If needed, FreeS/WAN attempts to create a connection
+ opportunistically. If this fails, FreeS/WAN blocks communication.
+ Inbound blocking is assumed to be done by the firewall. FreeS/WAN
+ offers firewall hooks but no modern firewall rules to help with inbound
+ blocking.</DD>
+<DT>private-or-clear</DT>
+<DD> FreeS/WAN prefers private communication with the listed CIDR
+ blocks. If needed, FreeS/WAN attempts to create a connection
+ opportunistically. If this fails, FreeS/WAN allows traffic in the
+ clear.</DD>
+<DT>clear-or-private</DT>
+<DD> FreeS/WAN communicates cleartext with the listed CIDR blocks, but
+ also accepts inbound OE connection requests from them. Also known as<A HREF="glossary.html#passive.OE">
+ passive OE (pOE)</A>, this policy may be used to create an<A HREF="glossary.html#responder">
+ opportunistic responder</A>.</DD>
+<DT>clear</DT>
+<DD> FreeS/WAN only communicates cleartext with the listed CIDR blocks.</DD>
+<DT>block</DT>
+<DD>FreeS/WAN blocks traffic to and from and the listed CIDR blocks.
+ Inbound blocking is assumed to be done by the firewall. FreeS/WAN
+ offers firewall hooks but no modern firewall rules to help with inbound
+ blocking.
+<!-- also called "blockdrop".-->
+</DD>
+</DL>
+<A NAME="policy.group.notes"></A>
+<P>Notes:</P>
+<UL>
+<LI>Base Policy Groups apply to communication with this host only.</LI>
+<LI>The most specific rule (whether policy or pre-configured connection)
+ applies. This has several practical applications:
+<UL>
+<LI>If CIDR blocks overlap, FreeS/WAN chooses the most specific
+ applicable block.</LI>
+<LI>This decision also takes into account any pre-configured connections
+ you may have.</LI>
+<LI>If the most specific connection is a pre-configured connection, the
+ following procedure applies. If that connection is up, it will be used.
+ If it is routed, it will be brought up. If it is added, no action will
+ be taken.</LI>
+</UL>
+</LI>
+<LI>Base Policy Groups are created using built-in connections. Details
+ in<A HREF="manpage.d/ipsec.conf.5.html"> man ipsec.conf</A>.</LI>
+<LI>All Policy Groups are bidirectional.<A HREF="src/policy-groups-table.html">
+ This chart</A> shows some technical details. FreeS/WAN does not support
+ one-way encryption, since it can give users a false sense of security.</LI>
+</UL>
+<H2><A NAME="4_2">Using Policy Groups</A></H2>
+<P>The Base Policy Groups which build IPsec connections rely on
+ Opportunistic Encryption. To use the following examples, you must first
+ become OE-capable, as described in our<A HREF="quickstart.html#quickstart">
+ quickstart guide</A>.<A NAME="example1"></A></P>
+<H3><A NAME="4_2_1">Example 1: Using a Base Policy Group</A></H3>
+<P>Simply place CIDR blocks (<A HREF="#dnswarning">names</A>, IPs or IP
+ ranges) in /etc/ipsec.d/policies/<VAR>[groupname]</VAR>, and reread the
+ policy group files.</P>
+<P>For example, the<VAR> private-or-clear</VAR> policy tells FreeS/WAN
+ to prefer encrypted communication to the listed CIDR blocks. Failing
+ that, it allows talk in the clear.</P>
+<P>To make this your default policy, place<A HREF="glossary.html#fullnet">
+ fullnet</A> in the<VAR> private-or-clear</VAR> policy group file:</P>
+<PRE>    [root@xy root]# cat /etc/ipsec.d/policies/private-or-clear
+    # This file defines the set of CIDRs (network/mask-length) to which
+    # communication should be private, if possible, but in the clear otherwise.
+    ....
+    0.0.0.0/0</PRE>
+<P>and reload your policies with</P>
+<PRE>    ipsec auto --rereadgroups</PRE>
+<P>Use<A HREF="quickstart.html#opp.test"> this test</A> to verify
+ opportunistic connections.</P>
+<A NAME="example2"></A>
+<H3><A NAME="4_2_2">Example 2: Defining IPsec Security Policy with
+ Groups</A></H3>
+<P>Defining IPsec security policy with Base Policy Groups is like
+ creating a shopping list: just put CIDR blocks in the appropriate group
+ files. For example:</P>
+<PRE>    [root@xy root]# cd /etc/ipsec.d/policies
+    [root@xy policies]# cat private
+        192.0.2.96/27              # The finance department
+        192.0.2.192/29             # HR
+	192.0.2.12                 # HR gateway
+        irc.private.example.com    # Private IRC server
+  
+    [root@xy policies]# cat private-or-clear
+        0.0.0.0/0                  # My default policy: try to encrypt.
+
+    [root@xy policies]# cat clear
+        192.0.2.18/32              # My POP3 server
+        192.0.2.19/32              # My Web proxy
+
+    [root@xy policies]# cat block
+        spamsource.example.com</PRE>
+<P>To make these settings take effect, type:</P>
+<PRE>    ipsec auto --rereadgroups</PRE>
+<P>Notes:</P>
+<UL>
+<LI>For opportunistic connection attempts to succeed, all participating
+ FreeS/WAN hosts and gateways must be configured for OE.</LI>
+<LI>Examples 3 through 5 show how to implement a detailed<VAR> private</VAR>
+ policy.</LI>
+<LI><A NAME="dnswarning"></A><FONT COLOR="RED"> Warning:</FONT> Using
+ DNS names in policy files and ipsec.conf can be tricky. If the name
+ does not resolve, the policy will not be implemented for that name. It
+ is therefore safer either to use IPs, or to put any critical names in
+ /etc/hosts. We plan to implement periodic DNS retry to help with this.
+<BR> Names are resolved at FreeS/WAN startup, or when the policies are
+ reloaded. Unfortunately, name lookup can hold up the startup process.
+ If you have fast DNS servers, the problem may be less severe.</LI>
+</UL>
+<A HREF="example3"></A>
+<H3><A NAME="4_2_3">Example 3: Creating a Simple IPsec VPN with the<VAR>
+ private</VAR> Group</A></H3>
+<P>You can create an IPsec VPN between several hosts, with only one line
+ of configuration per host, using the<VAR> private</VAR> policy group.</P>
+<P>First, use our<A HREF="quickstart.html"> quickstart guide</A> to set
+ up each participating host with a FreeS/WAN install and OE.</P>
+<P>In one host's<VAR> /etc/ipsec.d/policies/private</VAR>, list the
+ peers to which you wish to protect traffic. For example:</P>
+<PRE>    [root@xy root]# cd /etc/ipsec.d/policies
+    [root@xy policies]# cat private
+        192.0.2.9              # several hosts at example.com
+        192.0.2.11             
+        192.0.2.12                 
+        irc.private.example.com 
+</PRE>
+<P>Copy the<VAR> private</VAR> file to each host. Remove the local host,
+ and add the initial host.</P>
+<PRE>    scp2 /etc/ipsec.d/policies/private root@192.0.2.12:/etc/ipsec.d/policies/private</PRE>
+<P>On each host, reread the policy groups with</P>
+<PRE>    ipsec auto --rereadgroups</PRE>
+<P>That's it! You're configured.</P>
+<P>Test by pinging between two hosts. After a second or two, traffic
+ should flow, and</P>
+<PRE>    ipsec eroute</PRE>
+<P>should yield something like</P>
+<PRE>    192.0.2.11/32   -&gt; 192.0.2.8/32  =&gt; tun0x149f@192.0.2.8</PRE>
+<P>where your host IPs are substituted for 192.0.2.11 and 192.0.2.8.</P>
+<P>If traffic does not flow, there may be an error in your OE setup.
+ Revisit our<A HREF="quickstart.html"> quickstart guide</A>.</P>
+<P>Our next two examples show you how to add subnets to this IPsec VPN.</P>
+<A NAME="example4"></A>
+<H3><A NAME="4_2_4">Example 4: New Policy Groups to Protect a Subnet</A></H3>
+<P>To protect traffic to a subnet behind your FreeS/WAN gateway, you'll
+ need additional DNS records, and new policy groups. To set up the DNS,
+ see our<A HREF="quickstart.html#opp.gate"> quickstart guide</A>. To
+ create five new policy groups for your subnet, copy these connections
+ to<VAR> /etc/ipsec.conf</VAR>. Substitute your subnet's IPs for
+ 192.0.2.128/29.</P>
+<PRE>
+conn private-net
+    also=private  # inherits settings (eg. auto=start) from built in conn
+    leftsubnet=192.0.2.128/29  # your subnet's IPs here
+
+conn private-or-clear-net
+    also=private-or-clear
+    leftsubnet=192.0.2.128/29
+
+conn clear-or-private-net
+    also=clear-or-private
+    leftsubnet=192.0.2.128/29
+
+conn clear-net
+    also=clear
+    leftsubnet=192.0.2.128/29
+
+conn block-net
+    also=block
+    leftsubnet=192.0.2.128/29
+</PRE>
+<P>Copy the gateway's files to serve as the initial policy group files
+ for the new groups:</P>
+<PRE>
+    cp -p /etc/ipsec.d/policies/private /etc/ipsec.d/policies/private-net
+    cp -p /etc/ipsec.d/policies/private-or-clear /etc/ipsec.d/policies/private-or-clear-net
+    cp -p /etc/ipsec.d/policies/clear-or-private /etc/ipsec.d/policies/clear-or-private-net
+    cp -p /etc/ipsec.d/policies/clear /etc/ipsec.d/policies/clear-net
+    cp -p /etc/ipsec.d/policies/block /etc/ipsec.d/policies/block
+</PRE>
+<P><STRONG>Tip: Since a missing policy group file is equivalent to a
+ file with no entries, you need only create files for the connections
+ you'll use.</STRONG></P>
+<P>To test one of your new groups, place the fullnet 0.0.0.0/0 in<VAR>
+ private-or-clear-net</VAR>. Perform the subnet test in<A HREF="quickstart.html#opp.test">
+ our quickstart guide</A>. You should see a connection, and</P>
+<PRE>    ipsec eroute</PRE>
+<P>should include an entry which mentions the subnet node's IP and the
+ OE test site IP, like this:</P>
+<PRE>    192.0.2.131/32   -&gt; 192.139.46.77/32  =&gt; tun0x149f@192.0.2.11</PRE>
+<A HREF="example5"></A>
+<H3><A NAME="4_2_5">Example 5: Adding a Subnet to the VPN</A></H3>
+<P>Suppose you wish to secure traffic to a subnet 192.0.2.192/29 behind
+ a FreeS/WAN box 192.0.2.12.</P>
+<P>First, add DNS entries to configure 192.0.2.12 as an opportunistic
+ gateway for that subnet. Instructions are in our<A HREF="quickstart.html#opp.gate">
+ quickstart guide</A>. Next, create a<VAR> private-net</VAR> group on
+ 192.0.2.12 as described in<A HREF="#example4"> Example 4</A>.</P>
+<P>On each other host, add the subnet 192.0.2.192/29 to<VAR> private</VAR>
+, yielding for example</P>
+<PRE>    [root@xy root]# cd /etc/ipsec.d/policies
+    [root@xy policies]# cat private
+        192.0.2.9              # several hosts at example.com
+        192.0.2.11
+        192.0.2.12             # HR department gateway
+        192.0.2.192/29         # HR subnet
+        irc.private.example.com
+</PRE>
+<P>and reread policy groups with</P>
+<PRE>    ipsec auto --rereadgroups</PRE>
+<P>That's all the configuration you need.</P>
+<P>Test your VPN by pinging from a machine on 192.0.2.192/29 to any
+ other host:</P>
+<PRE>    [root@192.0.2.194]# ping 192.0.2.11</PRE>
+<P>After a second or two, traffic should flow, and</P>
+<PRE>    ipsec eroute</PRE>
+<P>should yield something like</P>
+<PRE>    192.0.2.11/32   -&gt; 192.0.2.194/32  =&gt; tun0x149f@192.0.2.12
+</PRE>
+<P>Key:</P>
+<TABLE>
+<TR><TD>1.</TD><TD>192.0.2.11/32</TD><TD>Local start point of the
+ protected traffic.</TD></TR>
+<TR><TD>2.</TD><TD>192.0.2.194/32</TD><TD>Remote end point of the
+ protected traffic.</TD></TR>
+<TR><TD>3.</TD><TD>192.0.2.12</TD><TD>Remote FreeS/WAN node (gateway or
+ host). May be the same as (2).</TD></TR>
+<TR><TD>4.</TD><TD>[not shown]</TD><TD>Local FreeS/WAN node (gateway or
+ host), where you've produced the output. May be the same as (1).</TD></TR>
+</TABLE>
+<P>For additional assurance, you can verify with a packet sniffer that
+ the traffic is being encrypted.</P>
+<P>Note</P>
+<UL>
+<LI>Because strangers may also connect via OE, this type of VPN may
+ require a stricter firewalling policy than a conventional VPN.</LI>
+</UL>
+<H2><A NAME="4_3">Appendix</A></H2>
+<A NAME="hiddenconn"></A>
+<H3><A NAME="4_3_1">Our Hidden Connections</A></H3>
+<P>Our Base Policy Groups are created using hidden connections. These
+ are spelled out in<A HREF="manpage.d/ipsec.conf.5.html"> man ipsec.conf</A>
+ and defined in<VAR> /usr/local/lib/ipsec/_confread</VAR>.</P>
+<A NAME="custom_policygroups"></A>
+<H3><A NAME="4_3_2">Custom Policy Groups</A></H3>
+<P>A policy group is built using a special connection description in<VAR>
+ ipsec.conf</VAR>, which:</P>
+<UL>
+<LI>is<STRONG> generic</STRONG>. It uses<VAR>
+ right=[%group|%opportunisticgroup]</VAR> rather than specific IPs. The
+ connection is cloned for every name or IP range listed in its Policy
+ Group file.</LI>
+<LI>often has a<STRONG> failure rule</STRONG>. This rule, written<VAR>
+ failureshunt=[passthrough|drop|reject|none]</VAR>, tells FreeS/WAN what
+ to do with packets for these CIDRs if it fails to establish the
+ connection. Default is<VAR> none</VAR>.</LI>
+</UL>
+<P>To create a new group:</P>
+<OL>
+<LI>Create its connection definition in<VAR> ipsec.conf</VAR>.</LI>
+<LI>Create a Policy Group file in<VAR> /etc/ipsec.d/policies</VAR> with
+ the same name as your connection.</LI>
+<LI>Put a CIDR block in that file.</LI>
+<LI>Reread groups with<VAR> ipsec auto --rereadgroups</VAR>.</LI>
+<LI>Test:<VAR> ping</VAR> to activate any OE connection, and view
+ results with<VAR> ipsec eroute</VAR>.</LI>
+</OL>
+<A NAME="disable_oe"></A><A NAME="disable_policygroups"></A>
+<H3><A NAME="4_3_3">Disabling Opportunistic Encryption</A></H3>
+<P>To disable OE (eg. policy groups and packetdefault), cut and paste
+ the following lines to<VAR> /etc/ipsec.conf</VAR>:</P>
+<PRE>conn block
+    auto=ignore
+
+conn private
+    auto=ignore
+
+conn private-or-clear
+    auto=ignore
+
+conn clear-or-private
+    auto=ignore
+
+conn clear
+    auto=ignore
+
+conn packetdefault
+    auto=ignore</PRE>
+<P>Restart FreeS/WAN so that the changes take effect:</P>
+<PRE>    ipsec setup restart</PRE>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="quickstart.html">Previous</A>
+<A HREF="faq.html">Next</A>
+</BODY>
+</HTML>
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
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+<A HREF="toc.html">Contents</A>
+<A HREF="umltesting.html">Previous</A>
+<A HREF="ipsec.html">Next</A>
+<HR>
+<H1><A name="politics">History and politics of cryptography</A></H1>
+<P>Cryptography has a long and interesting history, and has been the
+ subject of considerable political controversy.</P>
+<H2><A name="intro.politics">Introduction</A></H2>
+<H3><A NAME="26_1_1">History</A></H3>
+<P>The classic book on the history of cryptography is David Kahn's<A href="biblio.html#Kahn">
+ The Codebreakers</A>. It traces codes and codebreaking from ancient
+ Egypt to the 20th century.</P>
+<P>Diffie and Landau<A href="biblio.html#diffie"> Privacy on the Line:
+ The Politics of Wiretapping and Encryption</A> covers the history from
+ the First World War to the 1990s, with an emphasis on the US.</P>
+<H4>World War II</H4>
+<P>During the Second World War, the British &quot;Ultra&quot; project achieved one
+ of the greatest intelligence triumphs in the history of warfare,
+ breaking many Axis codes. One major target was the Enigma cipher
+ machine, a German device whose users were convinced it was unbreakable.
+ The American &quot;Magic&quot; project had some similar triumphs against Japanese
+ codes.</P>
+<P>There are many books on this period. See our bibliography for
+ several. Two I particularly like are:</P>
+<UL>
+<LI>Andrew Hodges has done a superb<A href="http://www.turing.org.uk/book/">
+ biography</A> of Alan Turing, a key player among the Ultra
+ codebreakers. Turing was also an important computer pioneer. The terms<A
+href="http://www.abelard.org/turpap/turpap.htm"> Turing test</A> and<A href="http://plato.stanford.edu/entries/turing-machine/">
+ Turing machine</A> are named for him, as is the<A href="http://www.acm.org">
+ ACM</A>'s highest technical<A href="http://www.acm.org/awards/taward.html">
+ award</A>.</LI>
+<LI>Neal Stephenson's<A href="biblio.html#neal"> Cryptonomicon</A> is a
+ novel with cryptography central to the plot. Parts of it take place
+ during WW II, other parts today.</LI>
+</UL>
+<P>Bletchley Park, where much of the Ultra work was done, now has a
+ museum and a<A href="http://www.bletchleypark.org.uk/"> web site</A>.</P>
+<P>The Ultra work introduced three major innovations.</P>
+<UL>
+<LI>The first break of Enigma was achieved by Polish Intelligence in
+ 1931. Until then most code-breakers had been linguists, but a different
+ approach was needed to break machine ciphers. Polish Intelligence
+ recruited bright young mathematicians to crack the &quot;unbreakable&quot;
+ Enigma. When war came in 1939, the Poles told their allies about this,
+ putting Britain on the road to Ultra. The British also adopted a
+ mathematical approach.</LI>
+<LI>Machines were extensively used in the attacks. First the Polish
+ &quot;Bombe&quot; for attacking Enigma, then British versions of it, then
+ machines such as Collosus for attacking other codes. By the end of the
+ war, some of these machines were beginning to closely resemble digital
+ computers. After the war, a team at Manchester University, several old
+ Ultra hands included, built one of the world's first actual
+ general-purpose digital computers.</LI>
+<LI>Ultra made codebreaking a large-scale enterprise, producing
+ intelligence on an industrial scale. This was not a &quot;black chamber&quot;,
+ not a hidden room in some obscure government building with a small crew
+ of code-breakers. The whole operation -- from wholesale interception of
+ enemy communications by stations around the world, through large-scale
+ code-breaking and analysis of the decrypted material (with an enormous
+ set of files for cross-referencing), to delivery of intelligence to
+ field commanders -- was huge, and very carefully managed.</LI>
+</UL>
+<P>So by the end of the war, Allied code-breakers were expert at
+ large-scale mechanised code-breaking. The payoffs were enormous.</P>
+<H4><A name="postwar">Postwar and Cold War</A></H4>
+<P>The wartime innovations were enthusiastically adopted by post-war and
+ Cold War signals intelligence agencies. Presumably many nations now
+ have some agency capable of sophisticated attacks on communications
+ security, and quite a few engage in such activity on a large scale.</P>
+<P>America's<A href="glossary.html#NSA"> NSA</A>, for example, is said
+ to be both the world's largest employer of mathematicians and the
+ world's largest purchaser of computer equipment. Such claims may be
+ somewhat exaggerated, but beyond doubt the NSA -- and similar agencies
+ in other countries -- have some excellent mathematicians, lots of
+ powerful computers, sophisticated software, and the organisation and
+ funding to apply them on a large scale. Details of the NSA budget are
+ secret, but there are some published<A href="http://www.fas.org/irp/nsa/nsabudget.html">
+ estimates</A>.</P>
+<P>Changes in the world's communications systems since WW II have
+ provided these agencies with new targets. Cracking the codes used on an
+ enemy's military or diplomatic communications has been common practice
+ for centuries. Extensive use of radio in war made large-scale attacks
+ such as Ultra possible. Modern communications make it possible to go
+ far beyond that. Consider listening in on cell phones, or intercepting
+ electronic mail, or tapping into the huge volumes of data on new media
+ such as fiber optics or satellite links. None of these targets existed
+ in 1950. All of them can be attacked today, and almost certainly are
+ being attacked.</P>
+<P>The Ultra story was not made public until the 1970s. Much of the
+ recent history of codes and code-breaking has not been made public, and
+ some of it may never be. Two important books are:</P>
+<UL>
+<LI>Bamford's<A href="biblio.html#puzzle"> The Puzzle Palace</A>, a
+ history of the NSA</LI>
+<LI>Hager's<A href="http://www.fas.org/irp/eprint/sp/index.html"> Secret
+ Power</A>, about the<A href="http://sg.yahoo.com/government/intelligence/echelon_network/">
+ Echelon</A> system -- the US, UK, Canada, Australia and New Zealand
+ co-operating to monitor much of the world's communications.</LI>
+</UL>
+<P>Note that these books cover only part of what is actually going on,
+ and then only the activities of nations open and democratic enough that
+ (some of) what they are doing can be discovered. A full picture,
+ including:</P>
+<UL>
+<LI>actions of the English-speaking democracies not covered in those
+ books</LI>
+<LI>actions of other more-or-less sane governments</LI>
+<LI>the activities of various more-or-less insane governments</LI>
+<LI>possibilities for unauthorized action by government employees</LI>
+<LI>possible actions by large non-government organisations:
+ corporations, criminals, or conspiracies</LI>
+</UL>
+<P>might be really frightening.</P>
+<H4><A name="recent">Recent history -- the crypto wars</A></H4>
+<P>Until quite recently, cryptography was primarily a concern of
+ governments, especially of the military, of spies, and of diplomats.
+ Much of it was extremely secret.</P>
+<P>In recent years, that has changed a great deal. With computers and
+ networking becoming ubiquitous, cryptography is now important to almost
+ everyone. Among the developments since the 1970s:</P>
+<UL>
+<LI>The US gov't established the Data Encryption Standard,<A href="glossary.html#DES">
+ DES</A>, a<A href="glossary.html#block"> block cipher</A> for
+ cryptographic protection of unclassfied documents.</LI>
+<LI>DES also became widely used in industry, especially regulated
+ industries such as banking.</LI>
+<LI>Other nations produced their own standards, such as<A href="glossary.html#GOST">
+ GOST</A> in the Soviet Union.</LI>
+<LI><A href="glossary.html#public">Public key</A> cryptography was
+ invented by Diffie and Hellman.</LI>
+<LI>Academic conferences such as<A href="http://www-cse.ucsd.edu/users/mihir/crypto2k.html">
+ Crypto</A> and<A href="http://www.esat.kuleuven.ac.be/cosic/eurocrypt2000/">
+ Eurocrypt</A> began.</LI>
+<LI>Several companies began offerring cryptographic products:<A href="glossary.html#RSAco">
+ RSA</A>,<A href="glossary.html#PGPI"> PGP</A>, the many vendors with<A href="glossary.html#PKI">
+ PKI</A> products, ...</LI>
+<LI>Cryptography appeared in other products: operating systems, word
+ processors, ...</LI>
+<LI>Network protocols based on crypto were developed:<A href="glossary.html#SSH">
+ SSH</A>,<A href="glossary.html#SSL"> SSL</A>,<A href="glossary.html#IPsec">
+ IPsec</A>, ...</LI>
+<LI>Crytography came into widespread use to secure bank cards,
+ terminals, ...</LI>
+<LI>The US government replaced<A href="glossary.html#DES"> DES</A> with
+ the much stronger Advanced Encryption Standard,<A href="glossary.html#AES">
+ AES</A></LI>
+</UL>
+<P>This has led to a complex ongoing battle between various mainly
+ government groups wanting to control the spread of crypto and various
+ others, notably the computer industry and the<A href="http://online.offshore.com.ai/security/">
+ cypherpunk</A> crypto advocates, wanting to encourage widespread use.</P>
+<P>Steven Levy has written a fine history of much of this, called<A href="biblio.html#crypto">
+ Crypto: How the Code rebels Beat the Government -- Saving Privacy in
+ the Digital Age</A>.</P>
+<P>The FreeS/WAN project is to a large extent an outgrowth of cypherpunk
+ ideas. Our reasons for doing the project can be seen in these quotes
+ from the<A href="http://www.eff.org/pub/Privacy/Crypto_misc/cypherpunk.manifesto">
+ Cypherpunk Manifesto</A>:</P>
+<BLOCKQUOTE> Privacy is necessary for an open society in the electronic
+ age. ...
+<P>We cannot expect governments, corporations, or other large, faceless
+ organizations to grant us privacy out of their beneficence. It is to
+ their advantage to speak of us, and we should expect that they will
+ speak. ...</P>
+<P>We must defend our own privacy if we expect to have any. ...</P>
+<P>Cypherpunks write code. We know that someone has to write software to
+ defend privacy, and since we can't get privacy unless we all do, we're
+ going to write it. We publish our code so that our fellow Cypherpunks
+ may practice and play with it. Our code is free for all to use,
+ worldwide. We don't much care if you don't approve of the software we
+ write. We know that software can't be destroyed and that a widely
+ dispersed system can't be shut down.</P>
+<P>Cypherpunks deplore regulations on cryptography, for encryption is
+ fundamentally a private act. ...</P>
+<P>For privacy to be widespread it must be part of a social contract.
+ People must come and together deploy these systems for the common good.
+ ...</P>
+</BLOCKQUOTE>
+<P>To quote project leader John Gilmore:</P>
+<BLOCKQUOTE> We are literally in a race between our ability to build and
+ deploy technology, and their ability to build and deploy laws and
+ treaties. Neither side is likely to back down or wise up until it has
+ definitively lost the race.</BLOCKQUOTE>
+<P>If FreeS/WAN reaches its goal of making<A href="intro.html#opp.intro">
+ opportunistic encryption</A> widespread so that secure communication
+ can become the default for a large part of the net, we will have struck
+ a major blow.</P>
+<H3><A name="intro.poli">Politics</A></H3>
+<P>The political problem is that nearly all governments want to monitor
+ their enemies' communications, and some want to monitor their citizens.
+ They may be very interested in protecting some of their own
+ communications, and often some types of business communication, but not
+ in having everyone able to communicate securely. They therefore attempt
+ to restrict availability of strong cryptography as much as possible.</P>
+<P>Things various governments have tried or are trying include:</P>
+<UL>
+<LI>Echelon, a monitor-the-world project of the US, UK, NZ, Australian
+ and Canadian<A href="glossary.html#SIGINT"> signals intelligence</A>
+ agencies. See this<A href="http://sg.yahoo.com/government/intelligence/echelon_network/">
+ collection</A> of links and this<A href="http://www.zdnet.com/zdnn/stories/news/0,4586,2640682,00.html">
+ story</A> on the French Parliament's reaction.</LI>
+<LI>Others governments may well have their own Echelon-like projects. To
+ quote the Dutch Minister of Defense, as reported in a German<A href="http://www.heise.de/tp/english/inhalt/te/4729/1.html">
+ magazine</A>:<BLOCKQUOTE> The government believes not only the
+ governments associated with Echelon are able to intercept communication
+ systems, but that it is an activity of the investigative authorities
+ and intelligence services of many countries with governments of
+ different political signature.</BLOCKQUOTE> Even if they have nothing
+ on the scale of Echelon, most intelligence agencies and police forces
+ certainly have some interception capability.</LI>
+<LI><A href="glossary.html#NSA">NSA</A> tapping of submarine
+ communication cables, described in<A href="http://www.zdnet.com/zdnn/stories/news/0,4586,2764372,00.html">
+ this article</A></LI>
+<LI>A proposal for international co-operation on<A href="http://www.heise.de/tp/english/special/enfo/4306/1.html">
+ Internet surveillance</A>.</LI>
+<LI>Alleged<A href="http://cryptome.org/nsa-sabotage.htm"> sabotage</A>
+ of security products by the<A href="glossary.html#NSA"> NSA</A> (the US
+ signals intelligence agency).</LI>
+<LI>The German armed forces and some government departments will stop
+ using American software for fear of NSA &quot;back doors&quot;, according to this<A
+href="http://www.theregister.co.uk/content/4/17679.html"> news story</A>
+.</LI>
+<LI>The British Regulation of Investigatory Powers bill. See this<A href="http://www.fipr.org/rip/index.html">
+ web page.</A> and perhaps this<A href="http://ars.userfriendly.org/cartoons/?id=20000806&amp;mode=classic">
+ cartoon</A>.</LI>
+<LI>A Russian<A href="http://www.eff.org/pub/Privacy/Foreign_and_local/Russia/russian_crypto_ban_english.edict">
+ ban</A> on cryptography</LI>
+<LI>Chinese<A href="http://www.eff.org/pub/Misc/Publications/Declan_McCullagh/www/global/china">
+ controls</A> on net use.</LI>
+<LI>The FBI's carnivore system for covert searches of email. See this<A href="http://www.zdnet.com/zdnn/stories/news/0,4586,2601502,00.html">
+ news coverage</A> and this<A href="http://www.crypto.com/papers/carnivore-risks.html">
+ risk assessment</A>. The government had an external review of some
+ aspects of this system done. See this<A href="http://www.crypto.com/papers/carnivore_report_comments.html">
+ analysis</A> of that review. Possible defenses against Carnivore
+ include:
+<UL>
+<LI><A href="glossary.html#PGP">PGP</A> for end-to-end mail encryption</LI>
+<LI><A href="http://www.home.aone.net.au/qualcomm/">secure sendmail</A>
+ for server-to-server encryption</LI>
+<LI>IPsec encryption on the underlying IP network</LI>
+</UL>
+</LI>
+<LI>export laws restricting strong cryptography as a munition. See<A href="#exlaw">
+ discussion</A> below.</LI>
+<LI>various attempts to convince people that fundamentally flawed
+ cryptography, such as encryption with a<A href="#escrow"> back door</A>
+ for government access to data or with<A href="#shortkeys"> inadequate
+ key lengths</A>, was adequate for their needs.</LI>
+</UL>
+<P>Of course governments are by no means the only threat to privacy and
+ security on the net. Other threats include:</P>
+<UL>
+<LI>industrial espionage, as for example in this<A href="http://www.zdnet.com/zdnn/stories/news/0,4586,2626931,00.html">
+ news story</A></LI>
+<LI>attacks by organised criminals, as in this<A href="http://www.sans.org/newlook/alerts/NTE-bank.htm">
+ large-scale attack</A></LI>
+<LI>collection of personal data by various companies.
+<UL>
+<LI>for example, consider the various corporate winners of Privacy
+ International's<A href="http://www.privacyinternational.org/bigbrother/">
+ Big Brother Awards</A>.</LI>
+<LI><A href="http://www.zeroknowledge.com">Zero Knowledge</A> sell tools
+ to defend against this</LI>
+</UL>
+</LI>
+<LI>individuals may also be a threat in a variety of ways and for a
+ variety of reasons</LI>
+<LI>in particular, an individual with access to government or industry
+ data collections could do considerable damage using that data in
+ unauthorized ways.</LI>
+</UL>
+<P>One<A href="http://www.zdnet.com/zdnn/stories/news/0,4586,2640674,00.html">
+ study</A> enumerates threats and possible responses for small and
+ medium businesses. VPNs are a key part of the suggested strategy.</P>
+<P>We consider privacy a human right. See the UN's<A href="http://www.un.org/Overview/rights.html">
+ Universal Declaration of Human Rights</A>, article twelve:</P>
+<BLOCKQUOTE> No one shall be subjected to arbitrary interference with
+ his privacy, family, home or correspondence, nor to attacks upon his
+ honor and reputation. Everyone has the right to the protection of the
+ law against such interference or attacks.</BLOCKQUOTE>
+<P>Our objective is to help make privacy possible on the Internet using
+ cryptography strong enough not even those well-funded government
+ agencies are likely to break it. If we can do that, the chances of
+ anyone else breaking it are negliible.</P>
+<H3><A NAME="26_1_3">Links</A></H3>
+<P>Many groups are working in different ways to defend privacy on the
+ net and elsewhere. Please consider contributing to one or more of these
+ groups:</P>
+<UL>
+<LI>the EFF's<A href="http://www.eff.org/crypto/"> Privacy Now!</A>
+ campaign</LI>
+<LI>the<A href="http://www.gilc.org"> Global Internet Liberty Campaign</A>
+</LI>
+<LI><A href="http://www.cpsr.org/program/privacy/privacy.html">Computer
+ Professionals for Social Responsibility</A></LI>
+</UL>
+<P>For more on these issues see:</P>
+<UL>
+<LI>Steven Levy (Newsweek's chief technology writer and author of the
+ classic &quot;Hackers&quot;) new book<A href="biblio.html#crypto"> Crypto: How
+ the Code Rebels Beat the Government--Saving Privacy in the Digital Age</A>
+</LI>
+<LI>Simson Garfinkel (Boston Globe columnist and author of books on<A href="biblio.html#PGP">
+ PGP</A> and<A href="biblio.html#practical"> Unix Security</A>) book<A href="biblio.html#Garfinkel">
+ Database Nation: the death of privacy in the 21st century</A></LI>
+</UL>
+<P>There are several collections of<A href="web.html#quotes"> crypto
+ quotes</A> on the net.</P>
+<P>See also the<A href="biblio.html"> bibliography</A> and our list of<A href="web.html#policy">
+ web references</A> on cryptography law and policy.</P>
+<H3><A NAME="26_1_4">Outline of this section</A></H3>
+<P>The remainder of this section includes two pieces of writing by our
+ project leader</P>
+<UL>
+<LI>his<A href="#gilmore"> rationale</A> for starting this</LI>
+<LI>another<A href="#policestate"> discussion</A> of project goals</LI>
+</UL>
+<P>and discussions of:</P>
+<UL>
+<LI><A href="#desnotsecure">why we do not use DES</A></LI>
+<LI><A href="#exlaw">cryptography export laws</A></LI>
+<LI>why<A href="#escrow"> government access to keys</A> is not a good
+ idea</LI>
+<LI>the myth that<A href="#shortkeys"> short keys</A> are adequate for
+ some security requirements</LI>
+</UL>
+<P>and a section on<A href="#press"> press coverage of FreeS/WAN</A>.</P>
+<H2><A name="leader">From our project leader</A></H2>
+<P>FreeS/WAN project founder John Gilmore wrote a web page about why we
+ are doing this. The version below is slightly edited, to fit this
+ format and to update some links. For a version without these edits, see
+ his<A href="http://www.toad.com/gnu/"> home page</A>.</P>
+<CENTER>
+<H3><A name="gilmore">Swan: Securing the Internet against Wiretapping</A>
+</H3>
+</CENTER>
+<P>My project for 1996 was to<B> secure 5% of the Internet traffic
+ against passive wiretapping</B>. It didn't happen in 1996, so I'm still
+ working on it in 1997, 1998, and 1999! If we get 5% in 1999 or 2000, we
+ can secure 20% the next year, against both active and passive attacks;
+ and 80% the following year. Soon the whole Internet will be private and
+ secure. The project is called S/WAN or S/Wan or Swan for Secure Wide
+ Area Network; since it's free software, we call it FreeSwan to
+ distinguish it from various commercial implementations.<A href="http://www.rsa.com/rsa/SWAN/">
+ RSA</A> came up with the term &quot;S/WAN&quot;. Our main web site is at<A href="http://www.freeswan.org/">
+ http://www.freeswan.org/</A>. Want to help?</P>
+<P>The idea is to deploy PC-based boxes that will sit between your local
+ area network and the Internet (near your firewall or router) which
+ opportunistically encrypt your Internet packets. Whenever you talk to a
+ machine (like a Web site) that doesn't support encryption, your traffic
+ goes out &quot;in the clear&quot; as usual. Whenever you connect to a machine
+ that does support this kind of encryption, this box automatically
+ encrypts all your packets, and decrypts the ones that come in. In
+ effect, each packet gets put into an &quot;envelope&quot; on one side of the net,
+ and removed from the envelope when it reaches its destination. This
+ works for all kinds of Internet traffic, including Web access, Telnet,
+ FTP, email, IRC, Usenet, etc.</P>
+<P>The encryption boxes are standard PC's that use freely available
+ Linux software that you can download over the Internet or install from
+ a cheap CDROM.</P>
+<P>This wasn't just my idea; lots of people have been working on it for
+ years. The encryption protocols for these boxes are called<A href="glossary.html#IPsec">
+ IPSEC (IP Security)</A>. They have been developed by the<A href="http://www.ietf.cnri.reston.va.us/html.charters/ipsec-charter.html">
+ IP Security Working Group</A> of the<A href="http://www.ietf.org/">
+ Internet Engineering Task Force</A>, and will be a standard part of the
+ next major version of the Internet protocols (<A href="http://playground.sun.com/pub/ipng/html/ipng-main.html">
+IPv6</A>). For today's (IP version 4) Internet, they are an option.</P>
+<P>The<A href="http://www.iab.org/iab"> Internet Architecture Board</A>
+ and<A href="http://www.ietf.org/"> Internet Engineering Steering Group</A>
+ have taken a<A href="iab-iesg.stmt"> strong stand</A> that the Internet
+ should use powerful encryption to provide security and privacy. I think
+ these protocols are the best chance to do that, because they can be
+ deployed very easily, without changing your hardware or software or
+ retraining your users. They offer the best security we know how to
+ build, using the Triple-DES, RSA, and Diffie-Hellman algorithms.</P>
+<P>This &quot;opportunistic encryption box&quot; offers the &quot;fax effect&quot;. As each
+ person installs one for their own use, it becomes more valuable for
+ their neighbors to install one too, because there's one more person to
+ use it with. The software automatically notices each newly installed
+ box, and doesn't require a network administrator to reconfigure it.
+ Instead of &quot;virtual private networks&quot; we have a &quot;REAL private network&quot;;
+ we add privacy to the real network instead of layering a
+ manually-maintained virtual network on top of an insecure Internet.</P>
+<H4>Deployment of IPSEC</H4>
+<P>The US government would like to control the deployment of IP Security
+ with its<A href="#exlaw"> crypto export laws</A>. This isn't a problem
+ for my effort, because the cryptographic work is happening outside the
+ United States. A foreign philanthropist, and others, have donated the
+ resources required to add these protocols to the Linux operating
+ system.<A href="http://www.linux.org/"> Linux</A> is a complete, freely
+ available operating system for IBM PC's and several kinds of
+ workstation, which is compatible with Unix. It was written by Linus
+ Torvalds, and is still maintained by a talented team of expert
+ programmers working all over the world and coordinating over the
+ Internet. Linux is distributed under the<A href="glossary.html#GPL">
+ GNU Public License</A>, which gives everyone the right to copy it,
+ improve it, give it to their friends, sell it commercially, or do just
+ about anything else with it, without paying anyone for the privilege.</P>
+<P>Organizations that want to secure their network will be able to put
+ two Ethernet cards into an IBM PC, install Linux on it from a $30 CDROM
+ or by downloading it over the net, and plug it in between their
+ Ethernet and their Internet link or firewall. That's all they'll have
+ to do to encrypt their Internet traffic everywhere outside their own
+ local area network.</P>
+<P>Travelers will be able to run Linux on their laptops, to secure their
+ connection back to their home network (and to everywhere else that they
+ connect to, such as customer sites). Anyone who runs Linux on a
+ standalone PC will also be able to secure their network connections,
+ without changing their application software or how they operate their
+ computer from day to day.</P>
+<P>There will also be numerous commercially available firewalls that use
+ this technology.<A href="http://www.rsa.com/"> RSA Data Security</A> is
+ coordinating the<A href="http://www.rsa.com/rsa/SWAN"> S/Wan (Secure
+ Wide Area Network)</A> project among more than a dozen vendors who use
+ these protocols. There's a<A href="http://www.rsa.com/rsa/SWAN/swan_test.htm">
+ compatability chart</A> that shows which vendors have tested their
+ boxes against which other vendors to guarantee interoperatility.</P>
+<P>Eventually it will also move into the operating systems and
+ networking protocol stacks of major vendors. This will probably take
+ longer, because those vendors will have to figure out what they want to
+ do about the export controls.</P>
+<H4>Current status</H4>
+<P>My initial goal of securing 5% of the net by Christmas '96 was not
+ met. It was an ambitious goal, and inspired me and others to work hard,
+ but was ultimately too ambitious. The protocols were in an early stage
+ of development, and needed a lot more protocol design before they could
+ be implemented. As of April 1999, we have released version 1.0 of the
+ software (<A href="ftp://ftp.xs4all.nl/freeswan/freeswan-1.0.tar.gz">
+freeswan-1.0.tar.gz</A>), which is suitable for setting up Virtual
+ Private Networks using shared secrets for authentication. It does not
+ yet do opportunistic encryption, or use DNSSEC for authentication;
+ those features are coming in a future release.</P>
+<DL>
+<DT>Protocols</DT>
+<DD>The low-level encrypted packet formats are defined. The system for
+ publishing keys and providing secure domain name service is defined.
+ The IP Security working group has settled on an NSA-sponsored protocol
+ for key agreement (called ISAKMP/Oakley), but it is still being worked
+ on, as the protocol and its documentation is too complex and
+ incomplete. There are prototype implementations of ISAKMP. The protocol
+ is not yet defined to enable opportunistic encryption or the use of
+ DNSSEC keys.</DD>
+<DT>Linux Implementation</DT>
+<DD>The Linux implementation has reached its first major release and is
+ ready for production use in manually-configured networks, using Linux
+ kernel version 2.0.36.</DD>
+<DT>Domain Name System Security</DT>
+<DD>There is now a release of BIND 8.2 that includes most DNS Security
+ features.
+<P>The first prototype implementation of Domain Name System Security was
+ funded by<A href="glossary.html#DARPA"> DARPA</A> as part of their<A href="http://www.darpa.mil/ito/research/is/index.html">
+ Information Survivability program</A>.<A href="http://www.tis.com">
+ Trusted Information Systems</A> wrote a modified version of<A href="http://www.isc.org/bind.html">
+ BIND</A>, the widely-used Berkeley implementation of the Domain Name
+ System.</P>
+<P>TIS, ISC, and I merged the prototype into the standard version of
+ BIND. The first production version that supports KEY and SIG records is<B>
+ bind-4.9.5</B>. This or any later version of BIND will do for
+ publishing keys. It is available from the<A href="http://www.isc.org/bind.html">
+ Internet Software Consortium</A>. This version of BIND is not
+ export-controlled since it does not contain any cryptography. Later
+ releases starting with BIND 8.2 include cryptography for authenticating
+ DNS records, which is also exportable. Better documentation is needed.</P>
+</DD>
+</DL>
+<H4>Why?</H4>
+<P>Because I can. I have made enough money from several successful
+ startup companies, that for a while I don't have to work to support
+ myself. I spend my energies and money creating the kind of world that
+ I'd like to live in and that I'd like my (future) kids to live in.
+ Keeping and improving on the civil rights we have in the United States,
+ as we move more of our lives into cyberspace, is a particular goal of
+ mine.</P>
+<H4>What You Can Do</H4>
+<DL>
+<DT>Install the latest BIND at your site.</DT>
+<DD>You won't be able to publish any keys for your domain, until you
+ have upgraded your copy of BIND. The thing you really need from it is
+ the new version of<I> named</I>, the Name Daemon, which knows about the
+ new KEY and SIG record types. So, download it from the<A href="http://www.isc.org/bind.html">
+ Internet Software Consortium</A> and install it on your name server
+ machine (or get your system administrator, or Internet Service
+ Provider, to install it). Both your primary DNS site and all of your
+ secondary DNS sites will need the new release before you will be able
+ to publish your keys. You can tell which sites this is by running the
+ Unix command &quot;dig MYDOMAIN ns&quot; and seeing which sites are mentioned in
+ your NS (name server) records.</DD>
+<DT>Set up a Linux system and run a 2.0.x kernel on it</DT>
+<DD>Get a machine running Linux (say the 5.2 release from<A href="http://www.redhat.com">
+ Red Hat</A>). Give the machine two Ethernet cards.</DD>
+<DT>Install the Linux IPSEC (Freeswan) software</DT>
+<DD>If you're an experienced sysadmin or Linux hacker, install the
+ freeswan-1.0 release, or any later release or snapshot. These releases
+ do NOT provide automated &quot;opportunistic&quot; operation; they must be
+ manually configured for each site you wish to encrypt with.</DD>
+<DT>Get on the linux-ipsec mailing list</DT>
+<DD>The discussion forum for people working on the project, and testing
+ the code and documentation, is: linux-ipsec@clinet.fi. To join this
+ mailing list, send email to<A href="mailto:linux-ipsec-REQUEST@clinet.fi">
+ linux-ipsec-REQUEST@clinet.fi</A> containing a line of text that says
+ &quot;subscribe linux-ipsec&quot;. (You can later get off the mailing list the
+ same way -- just send &quot;unsubscribe linux-ipsec&quot;).</DD>
+<P></P>
+<DT>Check back at this web page every once in a while</DT>
+<DD>I update this page periodically, and there may be new information in
+ it that you haven't seen. My intent is to send email to the mailing
+ list when I update the page in any significant way, so subscribing to
+ the list is an alternative.</DD>
+</DL>
+<P>Would you like to help? I can use people who are willing to write
+ documentation, install early releases for testing, write cryptographic
+ code outside the United States, sell pre-packaged software or systems
+ including this technology, and teach classes for network administrators
+ who want to install this technology. To offer to help, send me email at
+ gnu@toad.com. Tell me what country you live in and what your
+ citizenship is (it matters due to the export control laws; personally I
+ don't care). Include a copy of your resume and the URL of your home
+ page. Describe what you'd like to do for the project, and what you're
+ uniquely qualified for. Mention what other volunteer projects you've
+ been involved in (and how they worked out). Helping out will require
+ that you be able to commit to doing particular things, meet your
+ commitments, and be responsive by email. Volunteer projects just don't
+ work without those things.</P>
+<H4>Related projects</H4>
+<DL>
+<DT>IPSEC for NetBSD</DT>
+<DD>This prototype implementation of the IP Security protocols is for
+ another free operating system.<A href="ftp://ftp.funet.fi/pub/unix/security/net/ip/BSDipsec.tar.gz">
+ Download BSDipsec.tar.gz</A>.</DD>
+<DT>IPSEC for<A href="http://www.openbsd.org"> OpenBSD</A></DT>
+<DD>This prototype implementation of the IP Security protocols is for
+ yet another free operating system. It is directly integrated into the
+ OS release, since the OS is maintained in Canada, which has freedom of
+ speech in software.</DD>
+</DL>
+<H3><A name="policestate">Stopping wholesale monitoring</A></H3>
+<P>From a message project leader John Gilmore posted to the mailing
+ list:</P>
+<PRE>John Denker wrote:
+
+&gt; Indeed there are several ways in which the documentation overstates the 
+&gt; scope of what this project does -- starting with the name 
+&gt; FreeS/WAN.  There's a big difference between having an encrypted IP tunnel 
+&gt; versus having a Secure Wide-Area Network.  This software does a fine job of 
+&gt; the former, which is necessary but not sufficient for the latter.
+
+The goal of the project is to make it very hard to tap your wide area
+communications.  The current system provides very good protection
+against passive attacks (wiretapping and those big antenna farms).
+Active attacks, which involve the intruder sending packets to your
+system (like packets that break into sendmail and give them a root
+shell :-) are much harder to guard against.  Active attacks that
+involve sending people (breaking into your house and replacing parts
+of your computer with ones that transmit what you're doing) are also
+much harder to guard against.  Though we are putting effort into
+protecting against active attacks, it's a much bigger job than merely
+providing strong encryption.  It involves general computer security,
+and general physical security, which are two very expensive problems
+for even a site to solve, let alone to build into a whole society.
+
+The societal benefit of building an infrastructure that protects
+well against passive attacks is that it makes it much harder to do
+undetected bulk monitoring of the population.  It's a defense against
+police-states, not against policemen.
+
+Policemen can put in the effort required to actively attack sites that
+they have strong suspicions about.  But police states won't be able to
+build systems that automatically monitor everyone's communications.
+Either they will be able to monitor only a small subset of the
+populace (by targeting those who screwed up their passive security),
+or their monitoring activities will be detectable by those monitored
+(active attacks leave packet traces or footprints), which can then be
+addressed through the press and through political means if they become
+too widespread.
+
+FreeS/WAN does not protect very well against traffic analysis, which
+is a kind of widespread police-state style monitoring that still
+reveals significant information (who's talking to who) without
+revealing the contents of what was said.  Defenses against traffic
+analysis are an open research problem.  Zero Knowledge Systems is
+actively deploying a system designed to thwart it, designed by Ian
+Goldberg.  The jury is out on whether it actually works; a lot more
+experience with it will be needed.</PRE>
+<P>Notes on things mentioned in that message:</P>
+<UL>
+<LI>Denker is a co-author of a<A href="intro.html#applied"> paper</A> on
+ a large FreeS/WAN application.</LI>
+<LI>Information on Zero Knowledge is on their<A href="http://www.zks.net/">
+ web site</A>. Their Freedom product, designed to provide untracable
+ pseudonyms for use on the net, is no longer marketed.</LI>
+<LI>Another section of our documentation discusses ways to<A href="ipsec.html#traffic.resist">
+ resist traffic analysis</A>.</LI>
+</UL>
+<H2><A name="weak">Government promotion of weak crypto</A></H2>
+<P>Various groups, especially governments and especially the US
+ government, have a long history of advocating various forms of bogus
+ security.</P>
+<P>We regard bogus security as extremely dangerous. If users are
+ deceived into relying on bogus security, then they may be exposed to
+ large risks. They would be better off having no security and knowing
+ it. At least then they would be careful about what they said.</P>
+<P><STRONG>Avoiding bogus security is a key design criterion for
+ everything we do in FreeS/WAN</STRONG>. The most conspicuous example is
+ our refusal to support<A href="#desnotsecure"> single DES</A>. Other
+ IPsec &quot;features&quot; which we do not implement are discussed in our<A href="compat.html#dropped">
+ compatibility</A> document.</P>
+<H3><A name="escrow">Escrowed encryption</A></H3>
+<P>Various governments have made persistent attempts to encourage or
+ mandate &quot;escrowed encrytion&quot;, also called &quot;key recovery&quot;, or GAK for
+ &quot;government access to keys&quot;. The idea is that cryptographic keys be
+ held by some third party and turned over to law enforcement or security
+ agencies under some conditions.</P>
+<PRE>  Mary had a little key - she kept it in escrow,
+  and every thing that Mary said,
+  the feds were sure to know.</PRE>
+<P>A<A href="web.html#quotes"> crypto quotes</A> page attributes this to<A
+href="http://www.scramdisk.clara.net/"> Sam Simpson</A>.</P>
+<P>There is an excellent paper available on<A href="http://www.cdt.org/crypto/risks98/">
+ Risks of Escrowed Encryption</A>, from a group of cryptographic
+ luminaries which included our project leader.</P>
+<P>Like any unnecessary complication, GAK tends to weaken security of
+ any design it infects. For example:</P>
+<UL>
+<LI>Matt Blaze found a fatal flaw in the US government's Clipper chip
+ shortly after design information became public. See his paper &quot;Protocol
+ Failure in the Escrowed Encryption Standard&quot; on his<A href="http://www.crypto.com/papers/">
+ papers</A> page.</LI>
+<LI>a rather<A href="http://www.pgp.com/other/advisories/adk.asp"> nasty
+ bug</A> was found in the &quot;additional decryption keys&quot; &quot;feature&quot; of some
+ releases of<A href="glossary.html#PGP"> PGP</A></LI>
+</UL>
+<P>FreeS/WAN does not support escrowed encryption, and never will.</P>
+<H3><A name="shortkeys">Limited key lengths</A></H3>
+<P>Various governments, and some vendors, have also made persistent
+ attempts to convince people that:</P>
+<UL>
+<LI>weak systems are sufficient for some data</LI>
+<LI>strong cryptography should be reserved for cases where the extra
+ overheads are justified</LI>
+</UL>
+<P><STRONG>This is utter nonsense</STRONG>.</P>
+<P>Weak systems touted include:</P>
+<UL>
+<LI>the ludicrously weak (deliberately crippled) 40-bit ciphers that
+ until recently were all various<A href="#exlaw"> export laws</A>
+ allowed</LI>
+<LI>56-bit single DES, discussed<A href="#desnotsecure"> below</A></LI>
+<LI>64-bit symmetric ciphers and 512-bit RSA, the maximums for
+ unrestricted export under various current laws</LI>
+</UL>
+<P>The notion that choice of ciphers or keysize should be determined by
+ a trade-off between security requirements and overheads is pure
+ bafflegab.</P>
+<UL>
+<LI>For most<A href="glossary.html#symmetric"> symmetric ciphers</A>, it
+ is simply a lie. Any block cipher has some natural maximum keysize
+ inherent in the design -- 128 bits for<A href="glossary.html#IDEA">
+ IDEA</A> or<A href="glossary.html#CAST128"> CAST-128</A>, 256 for
+ Serpent or Twofish, 448 for<A href="glossary.html#Blowfish"> Blowfish</A>
+ and 2048 for<A href="glossary.html#RC4"> RC4</A>. Using a key size
+ smaller than that limit gives<EM> exactly zero</EM> savings in
+ overhead. The crippled 40-bit or 64-bit version of the cipher provides<EM>
+ no advantage whatsoever</EM>.</LI>
+<LI><A href="glossary.html#AES">AES</A> uses 10 rounds with 128-bit
+ keys, 12 rounds for 192-bit and 14 rounds for 256-bit, so there
+ actually is a small difference in overhead, but not enough to matter in
+ most applications.</LI>
+<LI>For<A href="glossary.html#3DES"> triple DES</A> there is a grain of
+ truth in the argument. 3DES is indeed three times slower than single
+ DES. However, the solution is not to use the insecure single DES, but
+ to pick a faster secure cipher.<A href="glossary.html#CAST128">
+ CAST-128</A>,<A href="glossary.html#Blowfish"> Blowfish</A> and the<A href="glossary.html#AES">
+ AES candidate</A> ciphers are are all considerably faster in software
+ than DES (let alone 3DES!), and apparently secure.</LI>
+<LI>For<A href="glossary.html#public"> public key</A> techniques, there
+ are extra overheads for larger keys, but they generally do not affect
+ overall performance significantly. Practical public key applications
+ are usually<A href="glossary.html#hybrid"> hybrid</A> systems in which
+ the bulk of the work is done by a symmetric cipher. The effect of
+ increasing the cost of the public key operations is typically
+ negligible because the public key operations use only a tiny fraction
+ of total resources.
+<P>For example, suppose public key operations use use 1% of the time in
+ a hybrid system and you triple the cost of public key operations. The
+ cost of symmetric cipher operations is unchanged at 99% of the original
+ total cost, so the overall effect is a jump from 99 + 1 = 100 to 99 + 3
+ = 102, a 2% rise in system cost.</P>
+</LI>
+</UL>
+<P>In short,<STRONG> there has never been any technical reason to use
+ inadequate ciphers</STRONG>. The only reason there has ever been for
+ anyone to use such ciphers is that government agencies want weak
+ ciphers used so that they can crack them. The alleged savings are
+ simply propaganda.</P>
+<PRE>   Mary had a little key (It's all she could export),
+   and all the email that she sent was opened at the Fort.</PRE>
+<P>A<A href="web.html#quotes"> crypto quotes</A> page attributes this to<A
+href="http://theory.lcs.mit.edu:80/~rivest/"> Ron Rivest</A>. NSA
+ headquarters is at Fort Meade, Maryland.</P>
+<P>Our policy in FreeS/WAN is to use only cryptographic components with
+ adequate keylength and no known weaknesses.</P>
+<UL>
+<LI>We do not implement single DES because it is clearly<A href="#desnotsecure">
+ insecure</A>, so implemeting it would violate our policy of avoiding
+ bogus security. Our default cipher is<A href="glossary.html#3DES"> 3DES</A>
+</LI>
+<LI>Similarly, we do not implement the 768-bit Group 1 for<A href="glossary.html#DH">
+ Diffie-Hellman</A> key negotiation. We provide only the 1024-bit Group
+ 2 and 1536-bit Group 5.</LI>
+</UL>
+<P>Detailed discussion of which IPsec features we implement or omit is
+ in out<A href="compat.html"> compatibility document</A>.</P>
+<P>These decisions imply that we cannot fully conform to the IPsec RFCs,
+ since those have DES as the only required cipher and Group 1 as the
+ only required DH group. (In our view, the standards were subverted into
+ offerring bogus security.) Fortunately, we can still interoperate with
+ most other IPsec implementations since nearly all implementers provide
+ at least 3DES and Group 2 as well.</P>
+<P>We hope that eventually the RFCs will catch up with our (and others')
+ current practice and reject dubious components. Some of our team and a
+ number of others are working on this in<A href="glossary.html#IETF">
+ IETF</A> working groups.</P>
+<H4>Some real trade-offs</H4>
+<P>Of course, making systems secure does involve costs, and trade-offs
+ can be made between cost and security. However, the real trade-offs
+ have nothing to do with using weaker ciphers.</P>
+<P>There can be substantial hardware and software costs. There are often
+ substantial training costs, both to train administrators and to
+ increase user awareness of security issues and procedures. There are
+ almost always substantial staff or contracting costs.</P>
+<P>Security takes staff time for planning, implementation, testing and
+ auditing. Some of the issues are subtle; you need good (hence often
+ expensive) people for this. You also need people to monitor your
+ systems and respond to problems. The best safe ever built is insecure
+ if an attacker can work on it for days without anyone noticing. Any
+ computer is insecure if the administrator is &quot;too busy&quot; to check the
+ logs.</P>
+<P>Moreover, someone in your organisation (or on contract to it) needs
+ to spend considerable time keeping up with new developments. EvilDoers<EM>
+ will</EM> know about new attacks shortly after they are found. You need
+ to know about them before your systems are attacked. If your vendor
+ provides a patch, you need to apply it. If the vendor does nothing, you
+ need to complain or start looking for another vendor.</P>
+<P>For a fairly awful example, see this<A href="http://www.sans.org/newlook/alerts/NTE-bank.htm">
+ report</A>. In that case over a million credit card numbers were taken
+ from e-commerce sites, using security flaws in Windows NT servers.
+ Microsoft had long since released patches for most or all of the flaws,
+ but the site administrators had not applied them.</P>
+<P>At an absolute minimum, you must do something about such issues<EM>
+ before</EM> an exploitation tool is posted to the net for downloading
+ by dozens of &quot;script kiddies&quot;. Such a tool might appear at any time
+ from the announcement of the security hole to several months later.
+ Once it appears, anyone with a browser and an attitude can break any
+ system whose administrators have done nothing about the flaw.</P>
+<P>Compared to those costs, cipher overheads are an insignificant factor
+ in the cost of security.</P>
+<P>The only thing using a weak cipher can do for you is to cause all
+ your other investment to be wasted.</P>
+<H2><A name="exlaw">Cryptography Export Laws</A></H2>
+<P>Many nations restrict the export of cryptography and some restrict
+ its use by their citizens or others within their borders.</P>
+<H3><A name="USlaw">US Law</A></H3>
+<P>US laws, as currently interpreted by the US government, forbid export
+ of most cryptographic software from the US in machine-readable form
+ without government permission. In general, the restrictions apply even
+ if the software is widely-disseminated or public-domain and even if it
+ came from outside the US originally. Cryptography is legally a munition
+ and export is tightly controlled under the<A href="glossary.html#EAR">
+ EAR</A> Export Administration Regulations.</P>
+<P>If you are a US citizen, your brain is considered US territory no
+ matter where it is physically located at the moment. The US believes
+ that its laws apply to its citizens everywhere, not just within the US.
+ Providing technical assistance or advice to foreign &quot;munitions&quot;
+ projects is illegal. The US government has very little sense of humor
+ about this issue and does not consider good intentions to be sufficient
+ excuse. Beware.</P>
+<P>The<A href="http://www.bxa.doc.gov/Encryption/"> official website</A>
+ for these regulations is run by the Commerce Department's Bureau of
+ Export Administration (BXA).</P>
+<P>The<A href="http://www.eff.org/bernstein/"> Bernstein case</A>
+ challenges the export restrictions on Constitutional grounds. Code is
+ speech so restrictions on export of code violate the First Amendment's
+ free speech provisions. This argument has succeeded in two levels of
+ court so far. It is quite likely to go on to the Supreme Court.</P>
+<P>The regulations were changed substantially in January 2000,
+ apparently as a government attempt to get off the hook in the Bernstein
+ case. It is now legal to export public domain source code for
+ encryption, provided you notify the<A href="glossary.html#BXA"> BXA</A>
+.</P>
+<P>There are, however, still restrictions in force. Moreover, the
+ regulations can still be changed again whenever the government chooses
+ to do so. Short of a Supreme Court ruling (in the Berstein case or
+ another) that overturns the regulations completely, the problem of
+ export regulation is not likely to go away in the forseeable future.</P>
+<H4><A name="UScontrib">US contributions to FreeS/WAN</A></H4>
+<P>The FreeS/WAN project<STRONG> cannot accept software contributions,<EM>
+ not even small bug fixes</EM>, from US citizens or residents</STRONG>.
+ We want it to be absolutely clear that our distribution is not subject
+ to US export law. Any contribution from an American might open that
+ question to a debate we'd prefer to avoid. It might also put the
+ contributor at serious legal risk.</P>
+<P>Of course Americans can still make valuable contributions (many
+ already have) by reporting bugs, or otherwise contributing to
+ discussions, on the project<A href="mail.html"> mailing list</A>. Since
+ the list is public, this is clearly constitutionally protected free
+ speech.</P>
+<P>Note, however, that the export laws restrict Americans from providing
+ technical assistance to foreign &quot;munitions&quot; projects. The government
+ might claim that private discussions or correspondence with FreeS/WAN
+ developers were covered by this. It is not clear what the courts would
+ do with such a claim, so we strongly encourage Americans to use the
+ list rather than risk the complications.</P>
+<H3><A name="wrong">What's wrong with restrictions on cryptography</A></H3>
+<P>Some quotes from prominent cryptography experts:</P>
+<BLOCKQUOTE> The real aim of current policy is to ensure the continued
+ effectiveness of US information warfare assets against individuals,
+ businesses and governments in Europe and elsewhere.
+<BR><A href="http://www.cl.cam.ac.uk/users/rja14"> Ross Anderson,
+ Cambridge University</A></BLOCKQUOTE><BLOCKQUOTE> If the government
+ were honest about its motives, then the debate about crypto export
+ policy would have ended years ago.
+<BR><A href="http://www.counterpane.com"> Bruce Schneier, Counterpane
+ Systems</A></BLOCKQUOTE><BLOCKQUOTE> The NSA regularly lies to people
+ who ask it for advice on export control. They have no reason not to;
+ accomplishing their goal by any legal means is fine by them. Lying by
+ government employees is legal.
+<BR> John Gilmore.</BLOCKQUOTE>
+<P>The Internet Architecture Board (IAB) and the Internet Engineering
+ Steering Group (IESG) made a<A href="iab-iesg.stmt"> strong statement</A>
+ in favour of worldwide access to strong cryptography. Essentially the
+ same statement is in the appropriately numbered<A href="ftp://ftp.isi.edu/in-notes/rfc1984.txt">
+ RFC 1984</A>. Two critical paragraphs are:</P>
+<BLOCKQUOTE> ... various governments have actual or proposed policies on
+ access to cryptographic technology ...
+<P>(a) ... export controls ...
+<BR> (b) ... short cryptographic keys ...
+<BR> (c) ... keys should be in the hands of the government or ...
+<BR> (d) prohibit the use of cryptology ...</P>
+<P>We believe that such policies are against the interests of consumers
+ and the business community, are largely irrelevant to issues of
+ military security, and provide only a marginal or illusory benefit to
+ law enforcement agencies, ...</P>
+<P>The IAB and IESG would like to encourage policies that allow ready
+ access to uniform strong cryptographic technology for all Internet
+ users in all countries.</P>
+</BLOCKQUOTE>
+<P>Our goal in the FreeS/WAN project is to build just such &quot;strong
+ cryptographic technology&quot; and to distribute it &quot;for all Internet users
+ in all countries&quot;.</P>
+<P>More recently, the same two bodies (IESG and IAB) have issued<A href="ftp://ftp.isi.edu/in-notes/rfc2804.txt">
+ RFC 2804</A> on why the IETF should not build wiretapping capabilities
+ into protocols for the convenience of security or law enforcement
+ agenicies. The abstract from that document is:</P>
+<BLOCKQUOTE> The Internet Engineering Task Force (IETF) has been asked
+ to take a position on the inclusion into IETF standards-track documents
+ of functionality designed to facilitate wiretapping.
+<P>This memo explains what the IETF thinks the question means, why its
+ answer is &quot;no&quot;, and what that answer means.</P>
+</BLOCKQUOTE> A quote from the debate leading up to that RFC:<BLOCKQUOTE>
+ We should not be building surveillance technology into standards. Law
+ enforcement was not supposed to be easy. Where it is easy, it's called
+ a police state.
+<BR> Jeff Schiller of MIT, in a discussion of FBI demands for wiretap
+ capability on the net, as quoted by<A href="http://www.wired.com/news/politics/0,1283,31895,00.html">
+ Wired</A>.</BLOCKQUOTE>
+<P>The<A href="http://www.ietf.org/mailman/listinfo/raven"> Raven</A>
+ mailing list was set up for this IETF discussion.</P>
+<P>Our goal is to go beyond that RFC and prevent Internet wiretapping
+ entirely.</P>
+<H3><A name="Wassenaar">The Wassenaar Arrangement</A></H3>
+<P>Restrictions on the export of cryptography are not just US policy,
+ though some consider the US at least partly to blame for the policies
+ of other nations in this area.</P>
+<P>A number of countries:</P>
+<P>Argentina, Australia, Austria, Belgium, Bulgaria, Canada, Czech
+ Republic, Denmark, Finland, France, Germany, Greece, Hungary, Ireland,
+ Italy, Japan, Luxembourg, Netherlands, New Zealand, Norway, Poland,
+ Portugal, Republic of Korea, Romania, Russian Federation, Slovak
+ Republic, Spain, Sweden, Switzerland, Turkey, Ukraine, United Kingdom
+ and United States</P>
+<P>have signed the Wassenaar Arrangement which restricts export of
+ munitions and other tools of war. Cryptographic sofware is covered
+ there.</P>
+<P>Wassenaar details are available from the<A href="http://www.wassenaar.org/">
+ Wassenaar Secretariat</A>, and elsewhere in a more readable<A href="http://www.fitug.de/news/wa/index.html">
+ HTML version</A>.</P>
+<P>For a critique see the<A href="http://www.gilc.org/crypto/wassenaar">
+ GILC site</A>:</P>
+<BLOCKQUOTE> The Global Internet Liberty Campaign (GILC) has begun a
+ campaign calling for the removal of cryptography controls from the
+ Wassenaar Arrangement.
+<P>The aim of the Wassenaar Arrangement is to prevent the build up of
+ military capabilities that threaten regional and international security
+ and stability . . .</P>
+<P>There is no sound basis within the Wassenaar Arrangement for the
+ continuation of any export controls on cryptographic products.</P>
+</BLOCKQUOTE>
+<P>We agree entirely.</P>
+<P>An interesting analysis of Wassenaar can be found on the<A href="http://www.cyber-rights.org/crypto/wassenaar.htm">
+ cyber-rights.org</A> site.</P>
+<H3><A name="status">Export status of Linux FreeS/WAN</A></H3>
+<P>We believe our software is entirely exempt from these controls since
+ the Wassenaar<A href="http://www.wassenaar.org/list/GTN%20and%20GSN%20-%2099.pdf">
+ General Software Note</A> says:</P>
+<BLOCKQUOTE> The Lists do not control &quot;software&quot; which is either:
+<OL>
+<LI>Generally available to the public by . . . retail . . . or</LI>
+<LI>&quot;In the public domain&quot;.</LI>
+</OL>
+</BLOCKQUOTE>
+<P>There is a note restricting some of this, but it is a sub-heading
+ under point 1, so it appears not to apply to public domain software.</P>
+<P>Their glossary defines &quot;In the public domain&quot; as:</P>
+<BLOCKQUOTE> . . . &quot;technology&quot; or &quot;software&quot; which has been made
+ available without restrictions upon its further dissemination.
+<P>N.B. Copyright restrictions do not remove &quot;technology&quot; or &quot;software&quot;
+ from being &quot;in the public domain&quot;.</P>
+</BLOCKQUOTE>
+<P>We therefore believe that software freely distributed under the<A href="glossary.html#GPL">
+ GNU Public License</A>, such as Linux FreeS/WAN, is exempt from
+ Wassenaar restrictions.</P>
+<P>Most of the development work is being done in Canada. Our
+ understanding is that the Canadian government accepts this
+ interpretation.</P>
+<UL>
+<LI>A web statement of<A href="http://www.dfait-maeci.gc.ca/~eicb/notices/ser113-e.htm">
+ Canadian policy</A> is available from the Department of Foreign Affairs
+ and International Trade.</LI>
+<LI>Another document from that department states that<A href="http://www.dfait-maeci.gc.ca/~eicb/export/gr1_e.htm">
+ public domain software</A> is exempt from the export controls.</LI>
+<LI>A researcher's<A href="http://insight.mcmaster.ca/org/efc/pages/doc/crypto-export.html">
+ analysis</A> of Canadian policy is also available.</LI>
+</UL>
+<P>Recent copies of the freely modifiable and distributable source code
+ exist in many countries. Citizens all over the world participate in its
+ use and evolution, and guard its ongoing distribution. Even if Canadian
+ policy were to change, the software would continue to evolve in
+ countries which do not restrict exports, and would continue to be
+ imported from there into unfree countries. &quot;The Net culture treats
+ censorship as damage, and routes around it.&quot;</P>
+<H3><A name="help">Help spread IPsec around</A></H3>
+<P>You can help. If you don't know of a Linux FreeS/WAN archive in your
+ own country, please download it now to your personal machine, and
+ consider making it publicly accessible if that doesn't violate your own
+ laws. If you have the resources, consider going one step further and
+ setting up a mirror site for the whole<A href="intro.html#munitions">
+ munitions</A> Linux crypto software archive.</P>
+<P>If you make Linux CD-ROMs, please consider including this code, in a
+ way that violates no laws (in a free country, or in a domestic-only CD
+ product).</P>
+<P>Please send a note about any new archive mirror sites or CD
+ distributions to linux-ipsec@clinet.fi so we can update the
+ documentation.</P>
+<P>Lists of current<A href="intro.html#sites"> mirror sites</A> and of<A href="intro.html#distwith">
+ distributions</A> which include FreeS/WAN are in our introduction
+ section.</P>
+<H2><A name="desnotsecure">DES is Not Secure</A></H2>
+<P>DES, the<STRONG> D</STRONG>ata<STRONG> E</STRONG>ncryption<STRONG> S</STRONG>
+tandard, can no longer be considered secure. While no major flaws in its
+ innards are known, it is fundamentally inadequate because its<STRONG>
+ 56-bit key is too short</STRONG>. It is vulnerable to<A href="glossary.html#brute">
+ brute-force search</A> of the whole key space, either by large
+ collections of general-purpose machines or even more quickly by
+ specialized hardware. Of course this also applies to<STRONG> any other
+ cipher with only a 56-bit key</STRONG>. The only reason anyone could
+ have for using a 56 or 64-bit key is to comply with various<A href="exportlaw.html">
+ export laws</A> intended to ensure the use of breakable ciphers.</P>
+<P>Non-government cryptologists have been saying DES's 56-bit key was
+ too short for some time -- some of them were saying it in the 70's when
+ DES became a standard -- but the US government has consistently
+ ridiculed such suggestions.</P>
+<P>A group of well-known cryptographers looked at key lengths in a<A href="http://www.counterpane.com/keylength.html">
+ 1996 paper</A>. They suggested a<EM> minimum</EM> of 75 bits to
+ consider an existing cipher secure and a<EM> minimum of 90 bits for new
+ ciphers</EM>. More recent papers, covering both<A href="glossary.html#symmetric">
+ symmetric</A> and<A href="glossary.html#public"> public key</A> systems
+ are at<A href="http://www.cryptosavvy.com/"> cryptosavvy.com</A> and<A href="http://www.rsasecurity.com/rsalabs/bulletins/bulletin13.html">
+ rsa.com</A>. For all algorithms, the minimum keylengths recommended in
+ such papers are significantly longer than the maximums allowed by
+ various export laws.</P>
+<P>In a<A href="http://www.privacy.nb.ca/cryptography/archives/cryptography/html/1998-09/0095.html">
+ 1998 ruling</A>, a German court described DES as &quot;out-of-date and not
+ safe enough&quot; and held a bank liable for using it.</P>
+<H3><A name="deshware">Dedicated hardware breaks DES in a few days</A></H3>
+<P>The question of DES security has now been settled once and for all.
+ In early 1998, the<A href="http://www.eff.org/"> Electronic Frontier
+ Foundation</A> built a<A href="http://www.eff.org/descracker.html">
+ DES-cracking machine</A>. It can find a DES key in an average of a few
+ days' search. The details of all this, including complete code listings
+ and complete plans for the machine, have been published in<A href="biblio.html#EFF">
+<CITE> Cracking DES</CITE></A>, by the Electronic Frontier Foundation.</P>
+<P>That machine cost just over $200,000 to design and build. &quot;Moore's
+ Law&quot; is that machines get faster (or cheaper, for the same speed) by
+ roughly a factor of two every 18 months. At that rate, their $200,000
+ in 1998 becomes $50,000 in 2001.</P>
+<P>However, Moore's Law is not exact and the $50,000 estimate does not
+ allow for the fact that a copy based on the published EFF design would
+ cost far less than the original. We cannot say exactly what such a
+ cracker would cost today, but it would likely be somewhere between
+ $10,000 and $100,000.</P>
+<P>A large corporation could build one of these out of petty cash. The
+ cost is low enough for a senior manager to hide it in a departmental
+ budget and avoid having to announce or justify the project. Any
+ government agency, from a major municipal police force up, could afford
+ one. Or any other group with a respectable budget -- criminal
+ organisations, political groups, labour unions, religious groups, ...
+ Or any millionaire with an obsession or a grudge, or just strange taste
+ in toys.</P>
+<P>One might wonder if a private security or detective agency would have
+ one for rent. They wouldn't need many clients to pay off that
+ investment.</P>
+<H3><A name="spooks">Spooks may break DES faster yet</A></H3>
+<P>As for the security and intelligence agencies of various nations,
+ they may have had DES crackers for years, and theirs may be much
+ faster. It is difficult to make most computer applications work well on
+ parallel machines, or to design specialised hardware to accelerate
+ them. Cipher-cracking is one of the very few exceptions. It is entirely
+ straightforward to speed up cracking by just adding hardware. Within
+ very broad limits, you can make it as fast as you like if you have the
+ budget. The EFF's $200,000 machine breaks DES in a few days. An<A href="http://www.planepage.com/">
+ aviation website</A> gives the cost of a B1 bomber as $200,000,000.
+ Spending that much, an intelligence agency could break DES in an
+ average time of<EM> six and a half minutes</EM>.</P>
+<P>That estimate assumes they use the EFF's 1998 technology and just
+ spend more money. They may have an attack that is superior to brute
+ force, they quite likely have better chip technology (Moore's law, a
+ bigger budget, and whatever secret advances they may have made) and of
+ course they may have spent the price of an aircraft carrier, not just
+ one aircraft.</P>
+<P>In short, we have<EM> no idea</EM> how quickly these organisations
+ can break DES. Unless they're spectacularly incompetent or horribly
+ underfunded, they can certainly break it, but we cannot guess how
+ quickly. Pick any time unit between days and milliseconds; none is
+ entirely unbelievable. More to the point, none of them is of any
+ comfort if you don't want such organisations reading your
+ communications.</P>
+<P>Note that this may be a concern even if nothing you do is a threat to
+ anyone's national security. An intelligence agency might well consider
+ it to be in their national interest for certain companies to do well.
+ If you're competing against such companies in a world market and that
+ agency can read your secrets, you have a serious problem.</P>
+<P>One might wonder about technology the former Soviet Union and its
+ allies developed for cracking DES during the Cold War. They must have
+ tried; the cipher was an American standard and widely used. Certainly
+ those countries have some fine mathematicians, and those agencies had
+ budget. How well did they succeed? Is their technology now for sale or
+ rent?</P>
+<H3><A name="desnet">Networks break DES in a few weeks</A></H3>
+<P>Before the definitive EFF effort, DES had been cracked several times
+ by people using many machines. See this<A href="http://www.distributed.net/pressroom/DESII-1-PR.html">
+ press release</A> for example.</P>
+<P>A major corporation, university, or government department could break
+ DES by using spare cycles on their existing collection of computers, by
+ dedicating a group of otherwise surplus machines to the problem, or by
+ combining the two approaches. It might take them weeks or months,
+ rather than the days required for the EFF machine, but they could do
+ it.</P>
+<P>What about someone working alone, without the resources of a large
+ organisation? For them, cracking DES will not be easy, but it may be
+ possible. A few thousand dollars buys a lot of surplus workstations. A
+ pile of such machines will certainly heat your garage nicely and might
+ break DES in a few months or years. Or enroll at a university and use
+ their machines. Or use an employer's machines. Or crack security
+ somewhere and steal the resources to crack a DES key. Or write a virus
+ that steals small amounts of resources on many machines. Or . . .</P>
+<P>None of these approaches are easy or break DES really quickly, but an
+ attacker only needs to find one that is feasible and breaks DES quickly
+ enough to be dangerous. How much would you care to bet that this will
+ be impossible if the attacker is clever and determined? How valuable is
+ your data? Are you authorised to risk it on a dubious bet?</P>
+<H3><A name="no_des">We disable DES</A></H3>
+<P>In short, it is now absolutely clear that<STRONG> DES is not secure</STRONG>
+ against</P>
+<UL>
+<LI>any<STRONG> well-funded opponent</STRONG></LI>
+<LI>any opponent (even a penniless one) with access (even stolen access)
+ to<STRONG> enough general purpose computers</STRONG></LI>
+</UL>
+<P>That is why<STRONG> Linux FreeS/WAN disables all transforms which use
+ plain DES</STRONG> for encryption.</P>
+<P>DES is in the source code, because we need DES to implement our
+ default encryption transform,<A href="glossary.html#3DES"> Triple DES</A>
+.<STRONG> We urge you not to use single DES</STRONG>. We do not provide
+ any easy way to enable it in FreeS/WAN, and our policy is to provide no
+ assistance to anyone wanting to do so.</P>
+<H3><A name="40joke">40-bits is laughably weak</A></H3>
+<P>The same is true, in spades, of ciphers -- DES or others -- crippled
+ by 40-bit keys, as many ciphers were required to be until recently
+ under various<A href="#exlaw"> export laws</A>. A brute force search of
+ such a cipher's keyspace is 2<SUP>16</SUP> times faster than a similar
+ search against DES. The EFF's machine can do a brute-force search of a
+ 40-bit key space in<EM> seconds</EM>. One contest to crack a 40-bit
+ cipher was won by a student<A href="http://catless.ncl.ac.uk/Risks/18.80.html#subj1">
+ using a few hundred idle machines at his university</A>. It took only
+ three and half hours.</P>
+<P>We do not, and will not, implement any 40-bit cipher.</P>
+<H3><A name="altdes">Triple DES is almost certainly secure</A></H3>
+<P><A href="glossary.html#3DES">Triple DES</A>, usually abbreviated
+ 3DES, applies DES three times, with three different keys. DES seems to
+ be basically an excellent cipher design; it has withstood several
+ decades of intensive analysis without any disastrous flaws being found.
+ It's only major flaw is that the small keyspace allows brute force
+ attacks to succeeed. Triple DES enlarges the key space to 168 bits,
+ making brute-force search a ridiculous impossibility.</P>
+<P>3DES is currently the only block cipher implemented in FreeS/WAN.
+ 3DES is, unfortunately, about 1/3 the speed of DES, but modern CPUs
+ still do it at quite respectable speeds. Some<A href="glossary.html#benchmarks">
+ speed measurements</A> for our code are available.</P>
+<H3><A name="aes.ipsec">AES in IPsec</A></H3>
+<P>The<A href="glossary.html#AES"> AES</A> project has chosen a
+ replacement for DES, a new standard cipher for use in non-classified US
+ government work and in regulated industries such as banking. This
+ cipher will almost certainly become widely used for many applications,
+ including IPsec.</P>
+<P>The winner, announced in October 2000 after several years of analysis
+ and discussion, was the<A href="http://www.esat.kuleuven.ac.be/~rijmen/rijndael/">
+ Rijndael</A> cipher from two Belgian designers.</P>
+<P>It is almost certain that FreeS/WAN will add AES support.<A href="web.html#patch">
+ AES patches</A> are already available.</P>
+<H2><A name="press">Press coverage of Linux FreeS/WAN:</A></H2>
+<H3><A NAME="26_6_1">FreeS/WAN 1.0 press</A></H3>
+<UL>
+<LI><A href="http://www.wired.com/news/news/technology/story/19136.html">
+Wired</A> &quot;Linux-Based Crypto Stops Snoops&quot;, James Glave April 15 1999</LI>
+<LI><A href="http://slashdot.org/articles/99/04/15/1851212.shtml">
+Slashdot</A></LI>
+<LI><A href="http://dgl.com/itinfo/1999/it990415.html">DGL</A>, Damar
+ Group Limited; looking at FreeS/WAN from a perspective of business
+ computing</LI>
+<LI><A href="http://linuxtoday.com/stories/5010.html">Linux Today</A></LI>
+<LI><A href="http://www.tbtf.com/archive/1999-04-21.html#Tcep">TBTF</A>,
+ Tasty Bits from the Technology Front</LI>
+<LI><A href="http://www.salonmagazine.com/tech/log/1999/04/16/encryption/index.html">
+Salon Magazine</A> &quot;Free Encryption Takes a Big Step&quot;</LI>
+</UL>
+<H3><A name="release">Press release for version 1.0</A></H3>
+<PRE>        Strong Internet Privacy Software Free for Linux Users Worldwide
+
+Toronto, ON, April 14, 1999 - 
+
+The Linux FreeS/WAN project today released free software to protect
+the privacy of Internet communications using strong encryption codes.
+FreeS/WAN automatically encrypts data as it crosses the Internet, to
+prevent unauthorized people from receiving or modifying it.  One
+ordinary PC per site runs this free software under Linux to become a
+secure gateway in a Virtual Private Network, without having to modify
+users' operating systems or application software.  The project built
+and released the software outside the United States, avoiding US
+government regulations which prohibit good privacy protection.
+FreeS/WAN version 1.0 is available immediately for downloading at
+http://www.xs4all.nl/~freeswan/.
+
+&quot;Today's FreeS/WAN release allows network administrators to build
+excellent secure gateways out of old PCs at no cost, or using a cheap
+new PC,&quot; said John Gilmore, the entrepreneur who instigated the
+project in 1996.  &quot;They can build operational experience with strong
+network encryption and protect their users' most important
+communications worldwide.&quot;
+
+&quot;The software was written outside the United States, and we do not
+accept contributions from US citizens or residents, so that it can be
+freely published for use in every country,&quot; said Henry Spencer, who
+built the release in Toronto, Canada.  &quot;Similar products based in the
+US require hard-to-get government export licenses before they can be
+provided to non-US users, and can never be simply published on a Web
+site.  Our product is freely available worldwide for immediate
+downloading, at no cost.&quot;
+
+FreeS/WAN provides privacy against both quiet eavesdropping (such as
+&quot;packet sniffing&quot;) and active attempts to compromise communications
+(such as impersonating participating computers).  Secure &quot;tunnels&quot; carry
+information safely across the Internet between locations such as a
+company's main office, distant sales offices, and roaming laptops.  This
+protects the privacy and integrity of all information sent among those
+locations, including sensitive intra-company email, financial transactions
+such as mergers and acquisitions, business negotiations, personal medical
+records, privileged correspondence with lawyers, and information about
+crimes or civil rights violations.  The software will be particularly
+useful to frequent wiretapping targets such as private companies competing
+with government-owned companies, civil rights groups and lawyers,
+opposition political parties, and dissidents. 
+
+FreeS/WAN provides privacy for Internet packets using the proposed
+standard Internet Protocol Security (IPSEC) protocols.  FreeS/WAN
+negotiates strong keys using Diffie-Hellman key agreement with 1024-bit
+keys, and encrypts each packet with 168-bit Triple-DES (3DES).  A modern
+$500 PC can set up a tunnel in less than a second, and can encrypt
+6 megabits of packets per second, easily handling the whole available
+bandwidth at the vast majority of Internet sites.  In preliminary testing,
+FreeS/WAN interoperated with 3DES IPSEC products from OpenBSD, PGP, SSH,
+Cisco, Raptor, and Xedia.  Since FreeS/WAN is distributed as source code,
+its innards are open to review by outside experts and sophisticated users,
+reducing the chance of undetected bugs or hidden security compromises.
+
+The software has been in development for several years.  It has been
+funded by several philanthropists interested in increased privacy on
+the Internet, including John Gilmore, co-founder of the Electronic
+Frontier Foundation, a leading online civil rights group.
+
+Press contacts:
+Hugh Daniel,   +1 408 353 8124, hugh@toad.com
+Henry Spencer, +1 416 690 6561, henry@spsystems.net
+
+* FreeS/WAN derives its name from S/WAN, which is a trademark of RSA Data
+  Security, Inc; used by permission.</PRE>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="umltesting.html">Previous</A>
+<A HREF="ipsec.html">Next</A>
+</BODY>
+</HTML>
diff --git a/doc/quickstart.html b/doc/quickstart.html
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
+H5 { font-family: sans-serif }
+H6 { font-family: sans-serif }
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+SUP { font-size: smaller }
+PRE { font-family: monospace }
+--></STYLE>
+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="upgrading.html">Previous</A>
+<A HREF="policygroups.html">Next</A>
+<HR>
+<H1><A name="quickstart">Quickstart Guide to Opportunistic Encryption</A>
+</H1>
+<A name="quick_guide"></A>
+<H2><A name="opp.setup">Purpose</A></H2>
+<P>This page will get you started using Linux FreeS/WAN with
+ opportunistic encryption (OE). OE enables you to set up IPsec tunnels
+ without co-ordinating with another site administrator, and without hand
+ configuring each tunnel. If enough sites support OE, a &quot;FAX effect&quot;
+ occurs, and many of us can communicate without eavesdroppers.</P>
+<H3><A NAME="3_1_1">OE &quot;flag day&quot;</A></H3>
+<P>As of FreeS/WAN 2.01, OE uses DNS TXT resource records (RRs) only
+ (rather than TXT with KEY). This change causes a<A href="http://jargon.watson-net.com/jargon.asp?w=flag+day">
+ &quot;flag day&quot;</A>. Users of FreeS/WAN 2.00 (or earlier) OE who are
+ upgrading may require additional resource records, as detailed in our<A href="upgrading.html#upgrading.flagday">
+ upgrading document</A>. OE setup instructions here are for 2.02 or
+ later.</P>
+<H2><A name="opp.dns">Requirements</A></H2>
+<P>To set up opportunistic encryption, you will need:</P>
+<UL>
+<LI>a Linux box. For OE to the public Internet, this box must NOT be
+ behind<A HREF="glossary.html#NAT.gloss"> Network Address Translation</A>
+ (NAT).</LI>
+<LI>to install Linux FreeS/WAN 2.02 or later</LI>
+<LI>either control over your reverse DNS (for full opportunism) or the
+ ability to write to some forward domain (for initiator-only).<A HREF="http://www.fdns.net">
+ This free DNS service</A> explicitly supports forward TXT records for
+ FreeS/WAN use.</LI>
+<LI>(for full opportunism) a static IP</LI>
+</UL>
+<P>Note: Currently, only Linux FreeS/WAN supports opportunistic
+ encryption.</P>
+<H2><A name="easy.install">RPM install</A></H2>
+<P>Our instructions are for a recent Red Hat with a 2.4-series stock or
+ Red Hat updated kernel. For other ways to install, see our<A href="install.html#install">
+ install document</A>.</P>
+<H3><A NAME="3_3_1">Download RPMs</A></H3>
+<P>If we have prebuilt RPMs for your Red Hat system, this command will
+ get them:</P>
+<PRE>    ncftpget ftp://ftp.xs4all.nl/pub/crypto/freeswan/binaries/RedHat-RPMs/`uname -r | tr -d 'a-wy-z'`/\*</PRE>
+<P>If that fails, you will need to try<A HREF="install.html"> another
+ install method</A>. Our kernel modules<B> will only work on the Red Hat
+ kernel they were built for</B>, since they are very sensitive to small
+ changes in the kernel.</P>
+<P>If it succeeds, you will have userland tools, a kernel module, and an
+ RPM signing key:</P>
+<PRE>    freeswan-module-2.04_2.4.20_20.9-0.i386.rpm
+    freeswan-userland-2.04_2.4.20_20.9-0.i386.rpm
+    freeswan-rpmsign.asc</PRE>
+<H3><A NAME="3_3_2">Check signatures</A></H3>
+<P>If you're running RedHat 8.x or later, import the RPM signing key
+ into the RPM database:</P>
+<PRE>    rpm --import freeswan-rpmsign.asc</PRE>
+<P>For RedHat 7.x systems, you'll need to add it to your<A HREF="glossary.html#PGP">
+ PGP</A> keyring:</P>
+<PRE>    pgp -ka freeswan-rpmsign.asc</PRE>
+<P>Check the digital signatures on both RPMs using:</P>
+<PRE>    rpm --checksig freeswan*.rpm </PRE>
+<P>You should see that these signatures are good:</P>
+<PRE>    freeswan-module-2.04_2.4.20_20.9-0.i386.rpm: pgp md5 OK
+    freeswan-userland-2.04_2.4.20_20.9-0.i386.rpm: pgp md5 OK</PRE>
+<H3><A NAME="3_3_3">Install the RPMs</A></H3>
+<P>Become root:</P>
+<PRE>    su</PRE>
+<P>Install your RPMs with:</P>
+<P></P>
+<PRE>    rpm -ivh freeswan*.rpm</PRE>
+<P>If you're upgrading from FreeS/WAN 1.x RPMs, and have problems with
+ that command, see<A HREF="upgrading.html#upgrading.rpms"> this note</A>
+.</P>
+<P>Then, start FreeS/WAN:</P>
+<PRE>    service ipsec start</PRE>
+<H3><A name="testinstall">Test</A></H3>
+<P>To check that you have a successful install, run:</P>
+<PRE>    ipsec verify</PRE>
+<P>You should see as part of the<VAR> verify</VAR> output:</P>
+<PRE>
+    Checking your system to see if IPsec got installed and started correctly
+    Version check and ipsec on-path                             [OK]
+    Checking for KLIPS support in kernel                        [OK]
+    Checking for RSA private key (/etc/ipsec.secrets)           [OK]
+    Checking that pluto is running                              [OK]
+    ...</PRE>
+<P>If any of these first four checks fails, see our<A href="trouble.html#install.check">
+ troubleshooting guide</A>.</P>
+<H2><A name="opp.setups.list">Our Opportunistic Setups</A></H2>
+<H3><A NAME="3_4_1">Full or partial opportunism?</A></H3>
+<P>Determine the best form of opportunism your system can support.</P>
+<UL>
+<LI>For<A HREF="#opp.incoming"> full opportunism</A>, you'll need a
+ static IP and and either control over your reverse DNS or an ISP that
+ can add the required TXT record for you.</LI>
+<LI>If you have a dynamic IP, and/or write access to forward DNS only,
+ you can do<A HREF="#opp.client"> initiate-only opportunism</A></LI>
+<LI>To protect traffic bound for real IPs behind your gateway, use<A HREF="adv_config.html#opp.gate">
+ this form of full opportunism</A>.</LI>
+</UL>
+<H2><A name="opp.client">Initiate-only setup</A></H2>
+<H3><A NAME="3_5_1">Restrictions</A></H3>
+<P>When you set up initiate-only Opportunistic Encryption (iOE):</P>
+<UL>
+<LI>there will be<STRONG> no incoming connection requests</STRONG>; you
+ can initiate all the IPsec connections you need.</LI>
+<LI><STRONG>only one machine is visible</STRONG> on your end of the
+ connection.</LI>
+<LI>iOE also protects traffic on behalf of<A HREF="glossary.html#NAT.gloss">
+ NATted</A> hosts behind the iOE box.</LI>
+</UL>
+<P>You cannot network a group of initiator-only machines if none of
+ these is capable of responding to OE. If one is capable of responding,
+ you may be able to create a hub topology using routing.</P>
+<H3><A name="forward.dns">Create and publish a forward DNS record</A></H3>
+<H4>Find a domain you can use</H4>
+<P>Find a DNS forward domain (e.g. example.com) where you can publish
+ your key. You'll need access to the DNS zone files for that domain.
+ This is common for a domain you own. Some free DNS providers, such as<A HREF="http://www.fdns.net">
+ this one</A>, also provide this service.</P>
+<P>Dynamic IP users take note: the domain where you place your key need
+ not be associated with the IP address for your system, or even with
+ your system's usual hostname.</P>
+<H4>Choose your ID</H4>
+<P>Choose a name within that domain which you will use to identify your
+ machine. It's convenient if this can be the same as your hostname:</P>
+<PRE>    [root@xy root]# hostname --fqdn
+    xy.example.com</PRE>
+<P>This name in FQDN (fully-qualified domain name) format will be your
+ ID, for DNS key lookup and IPsec negotiation.</P>
+<H4>Create a forward TXT record</H4>
+<P>Generate a forward TXT record containing your system's public key
+ with a command like:</P>
+<PRE>    ipsec showhostkey --txt @xy.example.com</PRE>
+<P>using your chosen ID in place of xy.example.com. This command takes
+ the contents of /etc/ipsec.secrets and reformats it into something
+ usable by ISC's BIND. The result should look like this (with the key
+ data trimmed down for clarity):</P>
+<PRE>
+    ; RSA 2192 bits   xy.example.com   Thu Jan  2 12:41:44 2003
+        IN      TXT     &quot;X-IPsec-Server(10)=@xy.example.com&quot; 
+    &quot;AQOF8tZ2... ...+buFuFn/&quot;
+</PRE>
+<H4>Publish the forward TXT record</H4>
+<P>Insert the record into DNS, or have a system adminstrator do it for
+ you. It may take up to 48 hours for the record to propagate, but it's
+ usually much quicker.</P>
+<H3><A NAME="3_5_3">Test that your key has been published</A></H3>
+<P>Check your DNS work</P>
+<PRE>    ipsec verify --host xy.example.com</PRE>
+<P>As part of the<VAR> verify</VAR> output, you ought to see something
+ like:</P>
+<PRE>    ...
+    Looking for TXT in forward map: xy.example.com          [OK]
+    ...</PRE>
+<P>For this type of opportunism, only the forward test is relevant; you
+ can ignore the tests designed to find reverse records.</P>
+<H3><A NAME="3_5_4">Configure, if necessary</A></H3>
+<P> If your ID is the same as your hostname, you're ready to go.
+ FreeS/WAN will use its<A HREF="policygroups.html"> built-in connections</A>
+ to create your iOE functionality.</P>
+<P>If you have chosen a different ID, you must tell FreeS/WAN about it
+ via<A HREF="manpage.d/ipsec.conf.5.html"><VAR> ipsec.conf</VAR></A>:</P>
+<PRE>    config setup
+        myid=@myname.freedns.example.com</PRE>
+<P>and restart FreeS/WAN:</P>
+<PRE>    service ipsec restart</PRE>
+<P>The new ID will be applied to the built-in connections.</P>
+<P>Note: you can create more complex iOE configurations as explained in
+ our<A HREF="policygroups.html#policygroups"> policy groups document</A>
+, or disable OE using<A HREF="policygroups.html#disable_policygroups">
+ these instructions</A>.</P>
+<H3><A NAME="3_5_5">Test</A></H3>
+<P>That's it!<A HREF="#opp.test"> Test your connections</A>.</P>
+<A name="opp.incoming"></A>
+<H2><A NAME="3_6">Full Opportunism</A></H2>
+<P>Full opportunism allows you to initiate and receive opportunistic
+ connections on your machine.</P>
+<A name="incoming.opp.dns"></A>
+<H3><A NAME="3_6_1">Put a TXT record in a Forward Domain</A></H3>
+<P>To set up full opportunism, first<A HREF="#forward.dns"> set up a
+ forward TXT record</A> as for<A HREF="#opp.client"> initiator-only OE</A>
+, using an ID (for example, your hostname) that resolves to your IP. Do
+ not configure<VAR> /etc/ipsec.conf</VAR>, but continue with the
+ instructions for full opportunism, below.</P>
+<P>Note that this forward record is not currently necessary for full OE,
+ but will facilitate future features.</P>
+<A name="incoming.opp.dns"></A>
+<H3><A NAME="3_6_2">Put a TXT record in Reverse DNS</A></H3>
+<P>You must be able to publish your DNS RR directly in the reverse
+ domain. FreeS/WAN will not follow a PTR which appears in the reverse,
+ since a second lookup at connection start time is too costly.</P>
+<H4>Create a Reverse DNS TXT record</H4>
+<P>This record serves to publicize your FreeS/WAN public key. In
+ addition, it lets others know that this machine can receive
+ opportunistic connections, and asserts that the machine is authorized
+ to encrypt on its own behalf.</P>
+<P>Use the command:</P>
+<PRE>    ipsec showhostkey --txt 192.0.2.11</PRE>
+<P>where you replace 192.0.2.11 with your public IP.</P>
+<P>The record (with key shortened) looks like:</P>
+<PRE>    ; RSA 2048 bits  xy.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;</PRE>
+<H4>Publish your TXT record</H4>
+<P>Send these records to your ISP, to be published in your IP's reverse
+ map. It may take up to 48 hours for these to propagate, but usually
+ takes much less time.</P>
+<H3><A NAME="3_6_3">Test your DNS record</A></H3>
+<P>Check your DNS work with</P>
+<PRE>    ipsec verify --host xy.example.com</PRE>
+<P>As part of the<VAR> verify</VAR> output, you ought to see something
+ like:</P>
+<PRE>    ...
+    Looking for TXT in reverse map: 11.2.0.192.in-addr.arpa [OK]
+    ...</PRE>
+<P>which indicates that you've passed the reverse-map test.</P>
+<H3><A NAME="3_6_4">No Configuration Needed</A></H3>
+<P>FreeS/WAN 2.x ships with full OE enabled, so you don't need to
+ configure anything. To enable OE out of the box, FreeS/WAN 2.x uses the
+ policy group<VAR> private-or-clear</VAR>, which creates IPsec
+ connections if possible (using OE if needed), and allows traffic in the
+ clear otherwise. You can create more complex OE configurations as
+ described in our<A HREF="policygroups.html#policygroups"> policy groups
+ document</A>, or disable OE using<A HREF="policygroups.html#disable_policygroups">
+ these instructions</A>.</P>
+<P>If you've previously configured for initiator-only opportunism,
+ remove<VAR> myid=</VAR> from<VAR> config setup</VAR>, so that peer
+ FreeS/WANs will look up your key by IP. Restart FreeS/WAN so that your
+ change will take effect, with</P>
+<PRE>    service ipsec restart</PRE>
+<H3><A NAME="3_6_5">Consider Firewalling</A></H3>
+<P>If you are running a default install of RedHat 8.x, take note: you
+ will need to alter your iptables rule setup to allow IPSec traffic
+ through your firewall. See<A HREF="firewall.html#simple.rules"> our
+ firewall document</A> for sample<VAR> iptables</VAR> rules.</P>
+<H3><A NAME="3_6_6">Test</A></H3>
+<P>That's it. Now,<A HREF="#opp.test"> test your connection</A>.</P>
+<H3><A NAME="3_6_7">Test</A></H3>
+<P>Instructions are in the next section.</P>
+<H2><A NAME="opp.test">Testing opportunistic connections</A></H2>
+<P>Be sure IPsec is running. You can see whether it is with:</P>
+<PRE>    ipsec setup status</PRE>
+<P>If need be, you can restart it with:</P>
+<PRE>    service ipsec restart</PRE>
+<P>Load a FreeS/WAN test website from the host on which you're running
+ FreeS/WAN. Note: the feds may be watching these sites. Type one of:</P>
+<P></P>
+<PRE>   links oetest.freeswan.org</PRE>
+<PRE>   links oetest.freeswan.nl</PRE>
+
+<!--<PRE>   links oetest.freeswan.ca</PRE>-->
+<P>A positive result looks like this:</P>
+<PRE>
+   You  seem  to  be  connecting  from:  192.0.2.11 which DNS says is:
+   gateway.example.com
+     _________________________________________________________________
+
+   Status E-route
+   OE    enabled    16    192.139.46.73/32    -&gt;    192.0.2.11/32   =&gt;
+   tun0x2097@192.0.2.11
+   OE    enabled    176    192.139.46.77/32    -&gt;   192.0.2.11/32   =&gt;
+   tun0x208a@192.0.2.11
+</PRE>
+<P>If you see this, congratulations! Your OE host or gateway will now
+ encrypt its own traffic whenever it can. For more OE tests, please see
+ our<A HREF="testing.html#test.oe"> testing document</A>. If you have
+ difficulty, see our<A HREF="#oe.trouble"> OE troubleshooting tips</A>.</P>
+<H2><A NAME="3_8">Now what?</A></H2>
+<P>Please see our<A HREF="policygroups.html"> policy groups document</A>
+ for more ways to set up Opportunistic Encryption.</P>
+<P>You may also wish to make some<A HREF="config.html"> pre-configured
+ connections</A>.</P>
+<H2><A NAME="3_9">Notes</A></H2>
+<UL>
+<LI>We assume some facts about your system in order to make
+ Opportunistic Encryption easier to configure. For example, we assume
+ that you wish to have FreeS/WAN secure your default interface.</LI>
+<LI>You may change this, and other settings, by altering the<VAR> config
+ setup</VAR> section in<VAR> /etc/ipsec.conf</VAR>.</LI>
+<LI>Note that the built-in connections used to build policy groups do
+ not inherit from<VAR> conn default</VAR>.</LI>
+
+<!--
+<LI>If you do not define your local identity
+(eg. <VAR>leftid</VAR>), this will be the IP address of your default
+FreeS/WAN interface.  
+-->
+<LI> If you fail to define your local identity and do not fill in your
+ reverse DNS entry, you will not be able to use OE.</LI>
+</UL>
+<A NAME="oe.trouble"></A>
+<H2><A NAME="3_10">Troubleshooting OE</A></H2>
+<P>See the OE troubleshooting hints in our<A HREF="trouble.html#oe.trouble">
+ troubleshooting guide</A>.</P>
+<A NAME="oe.known-issues"></A>
+<H2><A NAME="3_11">Known Issues</A></H2>
+<P>Please see<A HREF="opportunism.known-issues"> this list</A> of known
+ issues with Opportunistic Encryption.</P>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="upgrading.html">Previous</A>
+<A HREF="policygroups.html">Next</A>
+</BODY>
+</HTML>
diff --git a/doc/rfc.html b/doc/rfc.html
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
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+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="biblio.html">Previous</A>
+<A HREF="roadmap.html">Next</A>
+<HR>
+<H1><A name="RFC">IPsec RFCs and related documents</A></H1>
+<H2><A name="RFCfile">The RFCs.tar.gz Distribution File</A></H2>
+<P>The Linux FreeS/WAN distribution is available from<A href="http://www.xs4all.nl/~freeswan">
+ our primary distribution site</A> and various mirror sites. To give
+ people more control over their downloads, the RFCs that define IP
+ security are bundled separately in the file RFCs.tar.gz.</P>
+<P>The file you are reading is included in the main distribution and is
+ available on the web site. It describes the RFCs included in the<A href="#RFCs.tar.gz">
+ RFCs.tar.gz</A> bundle and gives some pointers to<A href="#sources">
+ other ways to get them</A>.</P>
+<H2><A name="sources">Other sources for RFCs &amp; Internet drafts</A></H2>
+<H3><A name="RFCdown">RFCs</A></H3>
+<P>RFCs are downloadble at many places around the net such as:</P>
+<UL>
+<LI><A href="http://www.rfc-editor.org">http://www.rfc-editor.org</A></LI>
+<LI><A href="http://nis.nsf.net/internet/documents/rfc">NSF.net</A></LI>
+<LI><A href="http://sunsite.doc.ic.ac.uk/computing/internet/rfc">Sunsite
+ in the UK</A></LI>
+</UL>
+<P>browsable in HTML form at others such as:</P>
+<UL>
+<LI><A href="http://www.landfield.com/rfcs/index.html">landfield.com</A></LI>
+<LI><A href="http://www.library.ucg.ie/Connected/RFC">Connected Internet
+ Encyclopedia</A></LI>
+</UL>
+<P>and some of them are available in translation:</P>
+<UL>
+<LI><A href="http://www.eisti.fr/eistiweb/docs/normes/">French</A></LI>
+</UL>
+<P>There is also a published<A href="biblio.html#RFCs"> Big Book of
+ IPSEC RFCs</A>.</P>
+<H3><A name="drafts">Internet Drafts</A></H3>
+<P>Internet Drafts, working documents which sometimes evolve into RFCs,
+ are also available.</P>
+<UL>
+<LI><A href="http://www.ietf.org/ID.html">Overall reference page</A></LI>
+<LI><A href="http://www.ietf.org/ids.by.wg/ipsec.html">IPsec</A> working
+ group</LI>
+<LI><A href="http://www.ietf.org/ids.by.wg/ipsra.html">IPSRA (IPsec
+ Remote Access)</A> working group</LI>
+<LI><A href="http://www.ietf.org/ids.by.wg/ipsp.html">IPsec Policy</A>
+ working group</LI>
+<LI><A href="http://www.ietf.org/ids.by.wg/kink.html">KINK (Kerberized
+ Internet Negotiation of Keys)</A> working group</LI>
+</UL>
+<P>Note: some of these may be obsolete, replaced by later drafts or by
+ RFCs.</P>
+<H3><A name="FIPS1">FIPS standards</A></H3>
+<P>Some things used by<A href="glossary.html#IPSEC"> IPsec</A>, such as<A
+href="glossary.html#DES"> DES</A> and<A href="glossary.html#SHA"> SHA</A>
+, are defined by US government standards called<A href="glossary.html#FIPS">
+ FIPS</A>. The issuing organisation,<A href="glossary.html#NIST"> NIST</A>
+, have a<A href="http://www.itl.nist.gov/div897/pubs"> FIPS home page</A>
+.</P>
+<H2><A name="RFCs.tar.gz">What's in the RFCs.tar.gz bundle?</A></H2>
+<P>All filenames are of the form rfc*.txt, with the * replaced with the
+ RFC number.</P>
+<PRE>RFC#        Title</PRE>
+<H3><A name="rfc.ov">Overview RFCs</A></H3>
+<PRE>2401        Security Architecture for the Internet Protocol
+2411        IP Security Document Roadmap</PRE>
+<H3><A name="basic.prot">Basic protocols</A></H3>
+<PRE>2402        IP Authentication Header
+2406        IP Encapsulating Security Payload (ESP)</PRE>
+<H3><A name="key.ike">Key management</A></H3>
+<PRE>2367        PF_KEY Key Management API, Version 2
+2407        The Internet IP Security Domain of Interpretation for ISAKMP
+2408        Internet Security Association and Key Management Protocol (ISAKMP)
+2409        The Internet Key Exchange (IKE)
+2412        The OAKLEY Key Determination Protocol
+2528        Internet X.509 Public Key Infrastructure</PRE>
+<H3><A name="rfc.detail">Details of various things used</A></H3>
+<PRE>2085        HMAC-MD5 IP Authentication with Replay Prevention
+2104        HMAC: Keyed-Hashing for Message Authentication
+2202        Test Cases for HMAC-MD5 and HMAC-SHA-1
+2207        RSVP Extensions for IPSEC Data Flows
+2403        The Use of HMAC-MD5-96 within ESP and AH
+2404        The Use of HMAC-SHA-1-96 within ESP and AH
+2405        The ESP DES-CBC Cipher Algorithm With Explicit IV
+2410        The NULL Encryption Algorithm and Its Use With IPsec
+2451        The ESP CBC-Mode Cipher Algorithms
+2521        ICMP Security Failures Messages</PRE>
+<H3><A name="rfc.ref">Older RFCs which may be referenced</A></H3>
+<PRE>1321        The MD5 Message-Digest Algorithm
+1828        IP Authentication using Keyed MD5
+1829        The ESP DES-CBC Transform
+1851        The ESP Triple DES Transform
+1852        IP Authentication using Keyed SHA</PRE>
+<H3><A name="rfc.dns">RFCs for secure DNS service, which IPsec may use</A>
+</H3>
+<PRE>2137        Secure Domain Name System Dynamic Update
+2230        Key Exchange Delegation Record for the DNS
+2535        Domain Name System Security Extensions
+2536        DSA KEYs and SIGs in the Domain Name System (DNS)
+2537        RSA/MD5 KEYs and SIGs in the Domain Name System (DNS)
+2538        Storing Certificates in the Domain Name System (DNS)
+2539        Storage of Diffie-Hellman Keys in the Domain Name System (DNS)</PRE>
+<H3><A name="rfc.exp">RFCs labelled &quot;experimental&quot;</A></H3>
+<PRE>2521        ICMP Security Failures Messages
+2522        Photuris: Session-Key Management Protocol
+2523        Photuris: Extended Schemes and Attributes</PRE>
+<H3><A name="rfc.rel">Related RFCs</A></H3>
+<PRE>1750        Randomness Recommendations for Security
+1918        Address Allocation for Private Internets
+1984        IAB and IESG Statement on Cryptographic Technology and the Internet
+2144        The CAST-128 Encryption Algorithm</PRE>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="biblio.html">Previous</A>
+<A HREF="roadmap.html">Next</A>
+</BODY>
+</HTML>
diff --git a/doc/roadmap.html b/doc/roadmap.html
new file mode 100644
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+++ b/doc/roadmap.html
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
+H5 { font-family: sans-serif }
+H6 { font-family: sans-serif }
+SUB { font-size: smaller }
+SUP { font-size: smaller }
+PRE { font-family: monospace }
+--></STYLE>
+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="rfc.html">Previous</A>
+<A HREF="umltesting.html">Next</A>
+<HR>
+<H1><A name="roadmap">Distribution Roadmap: What's Where in Linux
+ FreeS/WAN</A></H1>
+<P> This file is a guide to the locations of files within the FreeS/WAN
+ distribution. Everything described here should be on your system once
+ you download, gunzip, and untar the distribution.</P>
+<P>This distribution contains two major subsystems</P>
+<DL>
+<DT><A href="#klips.roadmap">KLIPS</A></DT>
+<DD>the kernel code</DD>
+<DT><A href="#pluto.roadmap">Pluto</A></DT>
+<DD>the user-level key-management daemon</DD>
+</DL>
+<P>plus assorted odds and ends.</P>
+<H2><A name="top">Top directory</A></H2>
+<P>The top directory has essential information in text files:</P>
+<DL>
+<DT>README</DT>
+<DD>introduction to the software</DD>
+<DT>INSTALL</DT>
+<DD>short experts-only installation procedures. More detalied procedures
+ are in<A href="install.html"> installation</A> and<A href="config.html">
+ configuration</A> HTML documents.</DD>
+<DT>BUGS</DT>
+<DD>major known bugs in the current release.</DD>
+<DT>CHANGES</DT>
+<DD>changes from previous releases</DD>
+<DT>CREDITS</DT>
+<DD>acknowledgement of contributors</DD>
+<DT>COPYING</DT>
+<DD>licensing and distribution information</DD>
+</DL>
+<H2><A name="doc">Documentation</A></H2>
+<P> The doc directory contains the bulk of the documentation, most of it
+ in HTML format. See the<A href="index.html"> index file</A> for
+ details.</P>
+<H2><A name="klips.roadmap">KLIPS: kernel IP security</A></H2>
+<P><A href="glossary.html#KLIPS"> KLIPS</A> is<STRONG> K</STRONG>erne<STRONG>
+L</STRONG><STRONG> IP</STRONG><STRONG> S</STRONG>ecurity. It lives in
+ the klips directory, of course.</P>
+<DL>
+<DT>klips/doc</DT>
+<DD>documentation</DD>
+<DT>klips/patches</DT>
+<DD>patches for existing kernel files</DD>
+<DT>klips/test</DT>
+<DD>test stuff</DD>
+<DT>klips/utils</DT>
+<DD>low-level user utilities</DD>
+<DT>klips/net/ipsec</DT>
+<DD>actual klips kernel files</DD>
+<DT>klips/src</DT>
+<DD>symbolic link to klips/net/ipsec
+<P>The &quot;make insert&quot; step of installation installs the patches and makes
+ a symbolic link from the kernel tree to klips/net/ipsec. The odd name
+ of klips/net/ipsec is dictated by some annoying limitations of the
+ scripts which build the Linux kernel. The symbolic-link business is a
+ bit messy, but all the alternatives are worse.</P>
+<P></P>
+</DD>
+<DT>klips/utils</DT>
+<DD>Utility programs:
+<P></P>
+<DL>
+<DT>eroute</DT>
+<DD>manipulate IPsec extended routing tables</DD>
+<DT>klipsdebug</DT>
+<DD>set Klips (kernel IPsec support) debug features and level</DD>
+<DT>spi</DT>
+<DD>manage IPsec Security Associations</DD>
+<DT>spigrp</DT>
+<DD>group/ungroup IPsec Security Associations</DD>
+<DT>tncfg</DT>
+<DD>associate IPsec virtual interface with real interface</DD>
+</DL>
+<P>These are all normally invoked by ipsec(8) with commands such as</P>
+<PRE>        ipsec tncfg <VAR>arguments</VAR></PRE>
+ There are section 8 man pages for all of these; the names have &quot;ipsec_&quot;
+ as a prefix, so your man command should be something like:
+<PRE>        man 8 ipsec_tncfg</PRE>
+</DD>
+</DL>
+<H2><A name="pluto.roadmap">Pluto key and connection management daemon</A>
+</H2>
+<P><A href="glossary.html#Pluto"> Pluto</A> is our key management and
+ negotiation daemon. It lives in the pluto directory, along with its
+ low-level user utility, whack.</P>
+<P> There are no subdirectories. Documentation is a man page,<A href="manpage.d/ipsec_pluto.8.html">
+ pluto.8</A>. This covers whack as well.</P>
+<H2><A name="utils">Utils</A></H2>
+<P> The utils directory contains a growing collection of higher-level
+ user utilities, the commands that administer and control the software.
+ Most of the things that you will actually have to run yourself are in
+ there.</P>
+<DL>
+<DT>ipsec</DT>
+<DD>invoke IPsec utilities
+<P>ipsec(8) is normally the only program installed in a standard
+ directory, /usr/local/sbin. It is used to invoke the others, both those
+ listed below and the ones in klips/utils mentioned above.</P>
+<P></P>
+</DD>
+<DT>auto</DT>
+<DD>control automatically-keyed IPsec connections</DD>
+<DT>manual</DT>
+<DD>take manually-keyed IPsec connections up and down</DD>
+<DT>barf</DT>
+<DD>generate copious debugging output</DD>
+<DT>look</DT>
+<DD>generate moderate amounts of debugging output</DD>
+</DL>
+<P> There are .8 manual pages for these. look is covered in barf.8. The
+ man pages have an &quot;ipsec_&quot; prefix so your man command should be
+ something like:</P>
+<PRE>
+        man 8 ipsec_auto
+</PRE>
+<P> Examples are in various files with names utils/*.eg</P>
+<H2><A name="lib">Libraries</A></H2>
+<H3><A name="fswanlib">FreeS/WAN Library</A></H3>
+<P> The lib directory is the FreeS/WAN library, also steadily growing,
+ used by both user-level and kernel code.
+<BR /> It includes section 3<A href="manpages.html"> man pages</A> for
+ the library routines.</P>
+<H3><A name="otherlib">Imported Libraries</A></H3>
+<H4>LibDES</H4>
+ The libdes library, originally from SSLeay, is used by both Klips and
+ Pluto for<A href="glossary.html#3DES"> Triple DES</A> encryption.
+ Single DES is not used because<A href="politics.html#desnotsecure"> it
+ is insecure</A>.
+<P> Note that this library has its own license, different from the<A href="glossary.html#GPL">
+ GPL</A> used for other code in FreeS/WAN.</P>
+<P> The library includes its own documentation.</P>
+<H4>GMP</H4>
+ The GMP (GNU multi-precision) library is used for multi-precision
+ arithmetic in Pluto's key-exchange code and public key code.
+<P> Older versions (up to 1.7) of FreeS/WAN included a copy of this
+ library in the FreeS/WAN distribution.</P>
+<P> Since 1.8, we have begun to rely on the system copy of GMP.</P>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="rfc.html">Previous</A>
+<A HREF="umltesting.html">Next</A>
+</BODY>
+</HTML>
diff --git a/doc/src/.cvsignore b/doc/src/.cvsignore
new file mode 100644
index 000000000..3ed29bc59
--- /dev/null
+++ b/doc/src/.cvsignore
@@ -0,0 +1,3 @@
+foo.xml
+foobar.html
+makecheck-2.html
diff --git a/doc/src/adv_config.html b/doc/src/adv_config.html
new file mode 100644
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+++ b/doc/src/adv_config.html
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+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>Advanced FreeS/WAN configuration</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, FreeSWAN, configuration">
+  <!--
+
+  Written by Sandy Harris for the Linux FreeS/WAN project
+  Maintained by Claudia Schmeing for same.
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: adv_config.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+
+<body>
+<h1><a name="adv_config">Other configuration possibilities</a></h1>
+
+<p>This document describes various options for FreeS/WAN configuration which
+are less used or more complex (often both) than the standard cases described
+in our <a href="config.html#config">config</a> and 
+<a href="quickstart.html#quick_guide">quickstart</a> documents.</p>
+
+<h2><a name="thumb">Some rules of thumb about configuration</a></h2>
+
+<h3><a name="cheap.tunnel">Tunnels are cheap</a></h3>
+
+<p>Nearly all of the overhead in IPsec processing is in the encryption and
+authentication of packets. Our <a href="performance.html">performance</a>
+document discusses these overheads.</p>
+
+<p>Beside those overheads, the cost of managing additional tunnels is
+trivial. Whether your gateway supports one tunnel or ten just does not
+matter. A hundred might be a problem; there is a <a
+href="performance.html#biggate">section</a> on this in the performance
+document.</p>
+
+<p>So, in nearly all cases, if using multiple tunnels gives you a reasonable
+way to describe what you need to do, you should describe it that way in your
+configuration files.</p>
+
+<p>For example, one user recently asked on a mailing list about this network
+configuration:</p>
+<pre>        netA---gwA---gwB---netB
+                            |----netC
+
+   netA and B are secured netC not.
+   netA and gwA can not access netC</pre>
+
+<p>The user had constructed only one tunnel, netA to netB, and wanted to know
+how to use ip-route to get netC packets into it. This is entirely
+unnecessary. One of the replies was:</p>
+<pre>  The simplest way and indeed the right way to
+  solve this problem is to set up two connections:
+
+        leftsubnet=NetA
+        left=gwA
+        right=gwB
+        rightsubnet=NetB
+  and
+        leftsubnet=NetA
+        left=gwA
+        right=gwB
+        rightsubnet=NetC</pre>
+
+<p>This would still be correct even if we added nets D, E, F,
+... to the above diagram and needed twenty tunnels.</p>
+
+<p>Of course another possibility would be to just use one tunnel, with a
+subnet mask that includes both netB and netC (or B, C, D, ...). See next
+section.</p>
+
+<p>In general, you can construct as many tunnels as you need. Networks like
+netC in this example that do not connect directly to the gateway are fine, as
+long as the gateway can route to them.</p>
+
+<p>The number of tunnels can become an issue if it reaches 50 or so. This is
+discussed in the <a href="performance.html#biggate">performance</a> document.
+Look there for information on supporting hundreds of Road Warriors from one
+gateway.</p>
+
+<p>If you find yourself with too many tunnels for some reason like having
+eight subnets at one location and nine at another so you end up with
+9*8=72 tunnels, read the next section here.</p>
+
+<h3><a name="subnet.size">Subnet sizes</a></h3>
+
+<p>The subnets used in <var>leftsubnet</var> and <var>rightsubnet</var> can
+be of any size that fits your needs, and they need not correspond to physical
+networks.</p>
+
+<p>You adjust the size by changing the <a href="glossary.html#subnet">subnet
+mask</a>, the number after the slash in the subnet description. For
+example</p>
+<ul>
+  <li>in 192.168.100.0/24 the /24 mask says 24 bits are used to designate the
+    network. This leave 8 bits to label machines. This subnet has 256
+    addresses. .0 and .255 are reserved, so it can have 254 machines.</li>
+  <li>A subnet with a /23 mask would be twice as large, 512 addresses.</li>
+  <li>A subnet with a /25 mask would be half the size, 128 addresses.</li>
+  <li>/0 is the whole Internet</li>
+  <li>/32 is a single machine</li>
+</ul>
+
+<p>As an example of using these in connection descriptions, suppose your
+company's head office has four physical networks using the address ranges:</p>
+<dl>
+  <dt>192.168.100.0/24</dt>
+    <dd>development</dd>
+  <dt>192.168.101.0/24</dt>
+    <dd>production</dd>
+  <dt>192.168.102.0/24</dt>
+    <dd>marketing</dd>
+  <dt>192.168.103.0/24</dt>
+    <dd>administration</dd>
+</dl>
+
+<p>You can use exactly those subnets in your connection descriptions, or use
+larger subnets to grant broad access if required:</p>
+<dl>
+  <dt>leftsubnet=192.168.100.0/24</dt>
+    <dd>remote hosts can access only development</dd>
+  <dt>leftsubnet=192.168.100.0/23</dt>
+    <dd>remote hosts can access development or production</dd>
+  <dt>leftsubnet=192.168.102.0/23</dt>
+    <dd>remote hosts can access marketing or administration</dd>
+  <dt>leftsubnet=192.168.100.0/22</dt>
+    <dd>remote hosts can access any of the four departments</dd>
+</dl>
+
+<p>or use smaller subnets to restrict access:</p>
+<dl>
+  <dt>leftsubnet=192.168.103.0/24</dt>
+    <dd>remote hosts can access any machine in administration</dd>
+  <dt>leftsubnet=192.168.103.64/28</dt>
+    <dd>remote hosts can access only certain machines in administration.</dd>
+  <dt>leftsubnet=192.168.103.42/32</dt>
+    <dd>remote hosts can access only one particular machine in
+    administration</dd>
+</dl>
+
+<p>To be exact, 192.68.103.64/28 means all addresses whose top 28 bits match
+192.168.103.64. There are 16 of these because there are  16 possibilities for
+the remainingg 4 bits. Their addresses are 192.168.103.64 to
+192.168.103.79.</p>
+
+<p>Each connection description can use a different subnet if required.</p>
+
+<p>It is possible to use all the examples above on the same FreeS/WAN
+gateway, each in a different connection description, perhaps for different
+classes of user or for different remote offices.</p>
+
+<p>It is also possible to have multiple tunnels using different
+<var>leftsubnet</var> descriptions with the same <var>right</var>. For
+example, when the marketing manager is on the road he or she might have
+access to:</p>
+<dl>
+  <dt>leftsubnet=192.168.102.0/24</dt>
+    <dd>all machines in marketing</dd>
+  <dt>192.168.101.32/29</dt>
+    <dd>some machines in production</dd>
+  <dt>leftsubnet=192.168.103.42/32</dt>
+    <dd>one particular machine in administration</dd>
+</dl>
+
+<p>This takes three tunnels, but tunnels are cheap. If the laptop is set up
+to build all three tunnels automatically, then he or she can access all these
+machines concurrently, perhaps from different windows.</p>
+
+<h3><a name="example.more">Other network layouts</a></h3>
+
+<p>Here is the usual network picture for a site-to-site VPN::</p>
+<pre>     Sunset==========West------------------East=========Sunrise
+           local net       untrusted net       local net</pre>
+
+<p>and for the Road Warrior::</p>
+<pre>                                           telecommuter's PC or
+                                           traveller's laptop
+     Sunset==========West------------------East
+         corporate LAN     untrusted net</pre>
+
+<p>Other configurations are also possible.</p>
+
+<h4><a name="internet.subnet">The Internet as a big subnet</a></h4>
+
+<p>A telecommuter might have:</p>
+<pre>     Sunset==========West------------------East ================= firewall --- the Internet
+         home network      untrusted net        corporate network</pre>
+
+<p>This can be described as a special case of the general subnet-to-subnet
+connection. The subnet on the right is 0.0.0.0/0, the whole Internet.</p>
+
+<p>West (the home gateway) can have its firewall rules set up so that only
+IPsec packets to East are allowed out. It will then behave as if its only
+connection to the world was a wire to East.</p>
+
+<p>When machines on the home network need to reach the Internet, they do so
+via the tunnel, East and the corporate firewall. From the viewpoint of the
+Internet (perhaps of some EvilDoer trying to break in!), those home office
+machines are behind the firewall and protected by it.</p>
+
+<h4><a name="wireless.config">Wireless</a></h4>
+
+<p>Another possible configuration comes up when you do not trust the local
+network, either because you have very high security standards or because your
+are using easily-intercepted wireless signals.</p>
+
+<p>Some wireless networks have built-in encryption called <a
+href="glossary.html#WEP">WEP</a>, but its security is dubious. It is a fairly
+common practice to use IPsec instead.</p>
+
+<p>In this case, part of your network may look like this:</p>
+<pre>          West-----------------------------East == the rest of your network
+     workstation   untrusted wireless net</pre>
+
+<p>Of course, there would likely be several wireless workstations, each with
+its own IPsec tunnel to the East gateway.</p>
+
+<p>The connection descriptions look much like Road Warrior descriptions:</p>
+<ul>
+  <li>each workstation should have its own unique
+    <ul>
+      <li>identifier for IPsec</li>
+      <li>RSA key</li>
+      <li>connection description.</li>
+    </ul>
+  </li>
+  <li>on the gateway, use <var>left=%any</var>, or the workstation IP
+  address</li>
+  <li>on workstations, <var>left=%defaultroute</var>, or the workstation IP
+    address</li>
+  <li><var>leftsubnet=</var> is not used.</li>
+</ul>
+
+<p>The <var>rightsubnet=</var> parameter might be set in any of several
+ways:</p>
+<dl>
+  <dt>rightsubnet=0.0.0.0/0</dt>
+    <dd>allowing workstations to access the entire Internet (see <a
+      href="#internet.subnet">above</a>)</dd>
+  <dt>rightsubnet=a.b.c.0/24</dt>
+    <dd>allowing access to your entire local network</dd>
+  <dt>rightsubnet=a.b.c.d/32</dt>
+    <dd>restricting the workstation to connecting to a particular server</dd>
+</dl>
+
+<p>Of course you can mix and match these as required. For example, a
+university might allow faculty full Internet access while letting student
+laptops connect only to a group of lab machines.</p>
+
+<h2><a name="choose">Choosing connection types</a></h2>
+
+<p>One choice you need to make before configuring additional connections is
+what type or types of connections you will use. There are several options,
+and you can use more than one concurrently.</p>
+
+<h3><a name="man-auto">Manual vs. automatic keying</a></h3>
+
+<p>IPsec allows two types of connections, with manual or automatic keying.
+FreeS/WAN starts them with commands such as:</p>
+<pre>        ipsec manual --up <var>name</var>
+        ipsec auto --up <var>name</var></pre>
+
+<p>The difference is in how they are keyed.</p>
+<dl>
+  <dt><a href="glossary.html#manual">Manually keyed</a> connections</dt>
+    <dd>use keys stored in <a
+      href="manpage.d/ipsec.conf.5.html">ipsec.conf</a>.</dd>
+  <dt><a href="glossary.html#auto">Automatically keyed</a> connections</dt>
+    <dd>use keys automatically generated by the Pluto key negotiation daemon.
+      The key negotiation protocol, <a href="glossary.html#IKE">IKE</a>, must
+      authenticate the other system. (It is vulnerable to a <a
+      href="glossary.html#middle">man-in-the-middle attack</a> if used
+      without authentication.) We currently support two authentication
+      methods:
+      <ul>
+        <li>using shared secrets stored in <a
+          href="manpage.d/ipsec.secrets.5.html">ipsec.secrets</a>.</li>
+        <li>RSA <a href="glossary.html#public">public key</a> authentication,
+          with our machine's private key in <a
+          href="manpage.d/ipsec.secrets.5.html">ipsec.secrets</a>. Public
+          keys for other machines may either be placed in <a
+          href="manpage.d/ipsec.conf.5.html">ipsec.conf</a> or provided via
+          DNS.</li>
+      </ul>
+        <p>A third method, using RSA keys embedded in <a
+        href="glossary.html#X509">X.509</a> certtificates, is provided by
+        user <a href="web.html#patch">patches</a>.</p>
+    </dd>
+</dl>
+
+<p><a href="glossary.html#manual">Manually keyed</a> connections provide
+weaker security than <a href="glossary.html#auto">automatically keyed</a>
+connections. An opponent who reads ipsec.secrets(5) gets your encryption key
+and can read all data encrypted by it. If he or she has an archive of old
+messages, all of them back to your last key change are also readable.</p>
+
+<p>With automatically-(re)-keyed connections, an opponent who reads
+ipsec.secrets(5) gets the key used to authenticate your system in IKE -- the
+shared secret or your private key, depending what authentication mechanism is
+in use. However, he or she does not automatically gain access to any
+encryption keys or any data.</p>
+
+<p>An attacker who has your authentication key can mount  a <a
+href="glossary.html#middle">man-in-the-middle attack</a> and, if that
+succeeds, he or she will get encryption keys and data. This is a serious
+danger, but it is better than having the attacker read everyting as soon as
+he or she breaks into ipsec.secrets(5).. Moreover, the keys change often so
+an opponent who gets one key does not get a large amount of data. To read all
+your data, he or she would have to do a man-in-the-middle attack at every key
+change.</p>
+
+<p>We discuss using <a href="#prodman">manual keying in production</a> below,
+but this is <strong>not recommended</strong> except in special circumstances,
+such as needing to communicate with some implementation that offers no
+auto-keyed mode compatible with FreeS/WAN.</p>
+
+<p>Manual keying may also be useful for testing. There is some discussion of
+this in our <a href="faq.html#man4debug">FAQ</a>.</p>
+
+<h3><a name="auto-auth">Authentication methods for auto-keying</a></h3>
+
+<p>The IKE protocol which Pluto uses to negotiate connections between
+gateways must use some form of authentication of peers. A gateway must know
+who it is talking to before it can create a secure connection. We support two
+basic methods for this authentication:</p>
+<ul>
+  <li>shared secrets, stored in <a
+    href="manpage.d/ipsec.secrets.5.html">ipsec.secrets(5)</a></li>
+  <li>RSA authentication</li>
+</ul>
+
+<p>There are, howver, several variations on the RSA theme, using different
+methods of managing the RSA keys:</p>
+<ul>
+  <li>our RSA private key in  <a
+    href="manpage.d/ipsec.secrets.5.html">ipsec.secrets(5)</a> with other
+    gateways' public keys
+    <dl>
+      <dt>either</dt>
+        <dd>stored in <a
+        href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a></dd>
+      <dt>or</dt>
+        <dd>looked up via <a href="glossary.html#DNS">DNS</a></dd>
+    </dl>
+  </li>
+  <li>authentication with <a href="glossary.html#x509">x.509</a>
+    certificates.; See our <a href="web.html#patch">links section</a> for
+    information on user-contributed patches for this.:</li>
+</ul>
+
+<p>Public keys in <a href="manpage.d/ipsec.conf.5.html">ipsec.conf(5</a>)
+give a reasonably straightforward method of specifying keys for explicitly
+configured connections.</p>
+
+<p>Putting public keys in DNS allows us to support <a
+href="glossary.html#carpediem">opportunistic encryption</a>. Any two
+FreeS/WAN gateways can provide secure communication, without either of them
+having any preset information about the other.</p>
+
+<p>X.509 certificates may be required to interface to various <a
+href="glossary.html#PKI">PKI</a>s.</p>
+
+<h3><a name="adv-pk">Advantages of public key methods</a></h3>
+
+<p>Authentication with a <a href="glossary.html#public">public key</a> method
+such as <a href="glossary.html#RSA">RSA</a> has some important advantages
+over using shared secrets.</p>
+<ul>
+  <li>no problem of secure transmission of secrets
+    <ul>
+      <li>A shared secret must be shared, so you have the problem of
+        transmitting it securely to the other party. If you get this wrong,
+        you have no security.</li>
+      <li>With a public key technique, you transmit only your public key. The
+        system is designed to ensure that it does not matter if an enemy
+        obtains public keys. The private key never leaves your machine.</li>
+    </ul>
+  </li>
+  <li>easier management
+    <ul>
+      <li>Suppose you have 20 branch offices all connecting to one gateway at
+        head office, and all using shared secrets. Then the head office admin
+        has 20 secrets to manage. Each of them must be kept secret not only
+        from outsiders, but also from 19 of the branch office admins. The
+        branch office admins have only one secret each to manage.
+        <p>If the branch offices need to talk to each other, this becomes
+        problematic. You need another 20*19/2 = 190 secrets for
+        branch-to-branch communication, each known to exactly two branches.
+        Now all the branch admins have the headache of handling 20 keys, each
+        shared with exactly one other branch or with head office.</p>
+        <p>For larger numbers of branches, the number of connections and
+        secrets increases quadratically  and managing them becomes a
+        nightmare. A 1000-gateway fully connected network needs 499,500
+        secrets, each known to exactly two players. There are ways to reduce
+        this problem, for example by introducing a central key server, but
+        these involve additional communication overheads, more administrative
+        work, and new threats that must be carefully guarded against.</p>
+      </li>
+      <li>With public key techniques, the <em>only</em> thing you have to
+        keep secret is your private key, and <em>you keep that secret from
+        everyone</em>.
+        <p>As network size increaes, the number of public keys used increases
+        linearly with the number of nodes. This still requires careful
+        administration in large applications, but is nothing like the
+        disaster of a quadratic increase. On a 1000-gateway network, you have
+        1000 private keys, each of which must be kept secure on one machine,
+        and 1000 public keys which must be distributed. This is not a trivial
+        problem, but it is manageable.</p>
+      </li>
+    </ul>
+  </li>
+  <li>does not require fixed IP addresses
+    <ul>
+      <li>When shared secrets are used in IPsec, the responder must be able
+        to tell which secret to use by looking at the IP address on the
+        incoming packets.  When the other parties do not have a fixed IP
+        address to be identified by (for example, on nearly all dialup ISP
+        connections and many cable or ADSL links), this does not work well --
+        all must share the same secret!</li>
+      <li>When RSA authentication is in use, the initiator can identify
+        itself by name before the key must be determined.  The responder then
+        checks that the message is signed with the public key corresponding
+        to that name.</li>
+    </ul>
+  </li>
+</ul>
+
+<p>There is also a disadvantage:</p>
+<ul>
+  <li>your private key is a single point of attack, extremely valuable to an
+    enemy
+    <ul>
+      <li>with shared secrets, an attacker who steals your ipsec.secrets file
+        can impersonate you or try <a
+        href="glossary.html#middle">man-in-the-middle</a> attacks, but can
+        only attack connections described in that file</li>
+      <li>an attacker who steals your private key gains the chance to attack
+        not only existing connections <em>but also any future
+        connections</em> created using that key</li>
+    </ul>
+  </li>
+</ul>
+
+<p>This is partly counterbalanced by the fact that the key is never
+transmitted and remains under your control at all times. It is likely
+necessary, however, to take account of this in setting security policy. For
+example, you should change gateway keys when an administrator leaves the
+company, and should change them periodically in any case.</p>
+
+<p>Overall, public key methods are <strong>more secure, more easily managed
+and more flexible</strong>. We recommend that they be used for all
+connections, unless there is a compelling reason to do otherwise.</p>
+
+<h2><a name="prodsecrets">Using shared secrets in production</a></h2>
+
+<p>Generally, public key methods are preferred for reasons given above, but
+shared secrets can be used with no loss of security, just more work and
+perhaps more need to take precautions.</p>
+
+<p>What I call "shared secrets" are sometimes also called "pre-shared keys".
+They are used only for for authentication, never for encryption. Calling them
+"pre-shared keys" has confused some users into thinking they were encryption
+keys, so I prefer to avoid the term..</p>
+
+<p>If you are interoperating with another IPsec implementation, you may find
+its documentation calling them "passphrases".</p>
+
+<h3><a name="secrets">Putting secrets in ipsec.secrets(5)</a></h3>
+
+<p>If shared secrets are to be used to <a
+href="glossary.html#authentication">authenticate</a> communication for the <a
+href="glossary.html#DH">Diffie-Hellman</a> key exchange in the <a
+href="glossary.html#IKE">IKE</a> protocol, then those secrets must be stored
+in <var>/etc/ipsec.secrets</var>. For details, see the <a
+href="manpage.d/ipsec.secrets.5.html">ipsec.secrets(5)</a> man page.</p>
+
+<p>A few considerations are vital:</p>
+<ul>
+  <li>make the secrets long and unguessable. Since they need not be
+    remembered by humans, very long ugly strings may be used. We suggest
+    using our <a href="manpage.d/ipsec_ranbits.8.html">ipsec_ranbits(8)</a>
+    utility to generate long (128 bits or more) random strings.</li>
+  <li>transmit secrets securely. You have to share them with other systems,
+    but you lose if they are intercepted and used against you. Use <a
+    href="glossary.html#PGP">PGP</a>, <a href="glossary.html#SSH">SSH</a>,
+    hand delivery of a floppy disk which is then destroyed, or some other
+    trustworthy method to deliver them.</li>
+  <li>store secrets securely, in root-owned files with permissions
+  rw------.</li>
+  <li>limit sharing of secrets. Alice, Bob, Carol and Dave may all talk to
+    each other, but only Alice and Bob should know the secret for an
+    Alice-Bob link.</li>
+  <li><strong>do not share private keys</strong>. The private key for RSA
+    authentication of your system is stored in <a
+    href="manpage.d/ipsec.secrets.5.html">ipsec.secrets(5)</a>, but it is a
+    different class of secret from the pre-shared keys used for the "shared
+    secret" authentication. No-one but you should have the RSA private
+  key.</li>
+</ul>
+
+<p>Each line has the IP addresses of the two gateways plus the secret. It
+should look something like this:</p>
+<pre>        10.0.0.1 11.0.0.1 : PSK "jxTR1lnmSjuj33n4W51uW3kTR55luUmSmnlRUuWnkjRj3UuTV4T3USSu23Uk55nWu5TkTUnjT"</pre>
+
+<p><var>PSK</var> indicates the use of a
+<strong>p</strong>re-<strong>s</strong>hared <strong>k</strong>ey. The quotes
+and the whitespace shown are required.</p>
+
+<p>You can use any character string as your secret. For security, it should
+be both long and extremely hard to guess. We provide a utility to generate
+such strings, <a
+href="manpage.d/ipsec_ranbits.8.html">ipsec_ranbits(8)</a>.</p>
+
+<p>You want the same secret on the two gateways used, so you create a line
+with that secret and the two gateway IP addresses. The installation process
+supplies an example secret, useful <em>only</em> for testing. You must change
+it for production use.</p>
+
+<h3><a name="securing.secrets">File security</a></h3>
+
+<p>You must deliver this file, or the relevant part of it, to the other
+gateway machine by some <strong>secure</strong> means. <em>Don't just FTP or
+mail the file!</em> It is vital that the secrets in it remain secret. An
+attacker who knew those could easily have <em>all the data on your "secure"
+connection</em>.</p>
+
+<p>This file must be owned by root and should have permissions
+<var>rw-------</var>.</p>
+
+<h3><a name="notroadshared">Shared secrets for road warriors</a></h3>
+
+<p>You can use a shared secret to support a single road warrior connecting to
+your gateway, and this is a reasonable thing to do in some circumstances.
+Public key methods have advantages, discussed <a href="#choose">above</a>,
+but they are not critical in this case.</p>
+
+<p>To do this, the line in ipsec.secrets(5) is something like:</p>
+<pre>        10.0.0.1 0.0.0.0 : PSK "jxTR1lnmSjuj33n4W51uW3kTR55luUmSmnlRUuWnkjRj3UuTV4T3USSu23Uk55nWu5TkTUnjT"</pre>
+where the <var>0.0.0.0</var> means that any IP address is acceptable.
+
+<p><strong>For more than one road warrior, shared secrets are <em>not</em> 
+recommended.</strong> If shared secrets are used, then when the responder
+needs to look up the secret, all it knows about the sender is an IP address.
+This is fine if the sender is at a fixed IP address specified in the config
+file. It is also fine if only one road warrior uses the wildcard
+<var>0.0.0.0</var> address. However, if you have more than one road warrior
+using shared secret authentication, then they must all use that wildcard and
+therefore <strong>all road warriors using PSK autentication must use the same
+secret</strong>. Obviously, this is insecure.</p>
+
+<p><strong>For multiple road warriors, use public key
+authentication.</strong> Each roadwarrior can then have its own identity (our
+<var>leftid=</var> or <var>rightid=</var> parameters), its own public/private
+key pair, and its own secure connection.</p>
+
+<h2><a name="prodman">Using manual keying in production</a></h2>
+
+<p>Generally, <a href="glossary.html#auto">automatic keying</a> is preferred
+over <a href="glossary.html#manual">manual keying</a> for production use
+because it is both easier to manage and more secure. Automatic keying frees
+the admin from much of the burden of managing keys securely, and can provide
+<a href="glossary.html#PFS">perfect forward secrecy</a>. This is discussed in
+more detail <a href="#man-auto">above</a>.</p>
+
+<p>However, it is possible to use manual keying in production if that is what
+you want to do. This might be necessary, for example, in order to
+interoperate with some device that either does not provide automatic keying
+or provides it in some version we cannot talk to.</p>
+
+<p>Note that with manual keying <strong>all security rests with the
+keys</strong>. If an adversary acquires your keys, you've had it. He or she
+can read everything ever sent with those keys, including old messages he or
+she may have archived.</p>
+
+<p>You need to <strong>be really paranoid about keys</strong> if you're going
+to rely on manual keying for anything important.</p>
+<ul>
+  <li>keep keys in files with 600 permissions, owned by root</li>
+  <li>be extremely careful about security of your gateway systems. Anyone who
+    breaks into a gateway and gains root privileges can get all your keys and
+    read everything ever encrypted with those keys, both old messages he has
+    archived and any new ones you may send.</li>
+  <li>change keys regularly. This can be a considerable bother, (and provides
+    an excellent reason to consider automatic keying instead), but it is
+    <em>absolutely essential</em> for security. Consider a manually keyed
+    system in which you leave the same key in place for months:
+    <ul>
+      <li>an attacker can have a very large sample of text sent with that key
+        to work with. This makes various cryptographic attacks much more
+        likely to succeed.</li>
+      <li>The chances of the key being compromised in some non-cryptographic
+        manner -- a spy finds it on a discarded notepad, someone breaks into
+        your server or your building and steals it, a staff member is bribed,
+        tricked, seduced or coerced into revealing it, etc. -- also increase
+        over time.</li>
+      <li>a successful attacker can read everything ever sent with that key.
+        This makes any successful attack extremely damaging.</li>
+    </ul>
+    It is clear that you must change keys often to have any useful security.
+    The only question is how often.</li>
+  <li>use <a href="glossary.html#PGP">PGP</a> or <a
+    href="glossary.html#SSH">SSH</a> for all key transfers</li>
+  <li>don't edit files with keys in them when someone can look over your
+    shoulder</li>
+  <li>worry about network security; could someone get keys by snooping
+    packets on the LAN between your X desktop and the gateway?</li>
+  <li>lock up your backup tapes for the gateway system</li>
+  <li>... and so on</li>
+</ul>
+
+<p>Linux FreeS/WAN provides some facilities to help with this. In particular,
+it is good policy to <strong>keep keys in separate files</strong> so you can
+edit configuration information in /etc/ipsec.conf without exposing keys to
+"shoulder surfers" or network snoops. We support this with the
+<var>also=</var> and <var>include</var> syntax in <a
+href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a>.</p>
+
+<p>See the last example in our <a href="examples">examples</a> file. In the
+/etc/ipsec.conf <var>conn samplesep</var> section, it has the line:</p>
+<pre>        also=samplesep-keys</pre>
+
+<p>which tells the "ipsec manual" script to insert the configuration
+description labelled "samplesep-keys" if it can find it. The /etc/ipsec.conf
+file must also have a line such as:</p>
+<pre>include ipsec.*.conf</pre>
+
+<p>which tells it to read other files. One of those other files then might
+contain the additional data:</p>
+<pre>conn samplesep-keys
+  spi=0x200
+  esp=3des-md5-96
+  espenckey=0x01234567_89abcdef_02468ace_13579bdf_12345678_9abcdef0
+  espauthkey=0x12345678_9abcdef0_2468ace0_13579bdf</pre>
+
+<p>The first line matches the label in the "also=" line, so the indented
+lines are inserted. The net effect is exactly as if the inserted lines had
+occurred in the original file in place of the "also=" line.</p>
+
+<p>Variables set here are:</p>
+<dl>
+  <dt>spi</dt>
+    <dd>A number needed by the manual keying code. Any 3-digit hex number
+      will do, but if you have more than one manual connection then
+      <strong>spi must be different</strong> for each connection.</dd>
+  <dt>esp</dt>
+    <dd>Options for <a href="glossary.html#ESP">ESP</a> (Encapsulated
+      Security Payload), the usual IPsec encryption mode. Settings here are
+      for <a href="glossary.html#encryption">encryption</a> using <a
+      href="glossary.html#3DES">triple DES</a> and <a
+      href="glossary.html#authentication">authentication</a> using <a
+      href="glossary.html#MD5">MD5</a>. Note that encryption without
+      authentication should not be used; it is insecure.</dd>
+  <dt>espenkey</dt>
+    <dd>Key for ESP encryption. Here, a 192-bit hex number for triple
+    DES.</dd>
+  <dt>espauthkey</dt>
+    <dd>Key for ESP authentication. Here, a 128-bit hex number for MD5.</dd>
+</dl>
+
+<p><strong>Note</strong> that the <strong>example keys we supply</strong> are
+intended <strong>only for testing</strong>. For real use, you should go to
+automatic keying. If that is not possible, create your own keys for manual
+mode and keep them secret</p>
+
+<p>Of course, any files containing keys <strong>must</strong> have 600
+permissions and be owned by root.</p>
+
+<p>If you connect in this way to multiple sites, we recommend that you keep
+keys for each site in a separate file and adopt some naming convention that
+lets you pick them all up with a single "include" line. This minimizes the
+risk of losing several keys to one error or attack and of accidentally giving
+another site admin keys which he or she has no business knowing.</p>
+
+<p>Also note that if you have multiple manually keyed connections on a single
+machine, then the <var>spi</var> parameter must be different for each one.
+Any 3-digit hex number is OK, provided they are different for each
+connection. We reserve the range 0x100 to 0xfff for manual connections. Pluto
+assigns SPIs from 0x1000 up for automatically keyed connections.</p>
+
+<p>If <a href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a> contains keys
+for manual mode connections, then it too must have permissions
+<var>rw-------</var>. We recommend instead that, if you must manual keying in
+production, you keep the keys in separate files.</p>
+
+<p>Note also that <a href="manpage.d/ipsec.conf.5.html">ipsec.conf</a> is
+installed with permissions <var>rw-r--r--</var>. If you plan to use manually
+keyed connections for anything more than initial testing, you <b>must</b>:</p>
+<ul>
+  <li>either change permissions to <var>rw-------</var></li>
+  <li>or store keys separately in secure files and access them via include
+    statements in <a href="manpage.d/ipsec.conf.5.html">ipsec.conf</a>.</li>
+</ul>
+
+<p>We recommend the latter method for all but the simplest configurations.</p>
+
+<h3><a name="ranbits">Creating keys with ranbits</a></h3>
+
+<p>You can create new <a href="glossary.html#random">random</a> keys with the
+<a href="manpage.d/ipsec_ranbits.8.html">ranbits(8)</a> utility. For example,
+the commands:</p>
+<pre>      umask 177
+      ipsec ranbits 192  &gt; temp
+      ipsec ranbits 128 &gt;&gt; temp</pre>
+
+<p>create keys in the sizes needed for our default algorithms:</p>
+<ul>
+  <li>192-bit key for <a href="glossary.html#3DES">3DES</a> encryption <br>
+    (only 168 bits are used; parity bits are ignored)</li>
+  <li>128-bit key for keyed <a href="glossary.html#MD5">MD5</a>
+  authentication</li>
+</ul>
+
+<p>If you want to use <a href="glossary.html#SHA">SHA</a> instead of <a
+href="glossary.html#MD5">MD5</a>, that requires a 160-bit key</p>
+
+<p>Note that any <strong>temporary files</strong> used must be kept
+<strong>secure</strong> since they contain keys. That is the reason for the
+umask command above. The temporary file should be deleted as soon as you are
+done with it. You may also want to change the umask back to its default value
+after you are finished working on keys.</p>
+
+<p>The ranbits utility may pause for a few seconds if not enough entropy is
+available immediately. See ipsec_ranbits(8) and random(4) for details. You
+may wish to provide some activity to feed entropy into the system. For
+example, you might move the mouse around, type random characters, or do
+<var>du /usr &gt; /dev/null</var> in the background.</p>
+
+<h2><a name="boot">Setting up connections at boot time</a></h2>
+
+<p>You can tell the system to set up connections automatically at boot time
+by putting suitable stuff in /etc/ipsec.conf on both systems. The relevant
+section of the file is labelled by a line reading <var>config setup</var>.</p>
+
+<p>Details can be found in the <a
+href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a> man page. We also
+provide a file of <a href="examples">example configurations</a>.</p>
+
+<p>The most likely options are something like:</p>
+<dl>
+  <dt>interfaces="ipsec0=eth0 ipsec1=ppp0"</dt>
+    <dd>Tells KLIPS which interfaces to use. Up to four interfaces numbered
+      ipsec[0-3] are supported. Each interface can support an arbitrary
+      number of tunnels.
+      <p>Note that for PPP, you give the ppp[0-9] device name here, not the
+      underlying device such as modem (or eth1 if you are using PPPoE).</p>
+    </dd>
+  <dt>interfaces=%defaultroute</dt>
+    <dd>Alternative setting, useful in simple cases. KLIPS will pick up both
+      its interface and the next hop information from the settings of the
+      Linux default route.</dd>
+  <dt>forwardcontrol=no</dt>
+    <dd>Normally "no". Set to "yes" if the IP forwarding option is disabled
+      in your network configuration. (This can be set as a kernel
+      configuration option or later. e.g. on Redhat, it's in
+      /etc/sysconfig/network and on SuSE you can adjust it with Yast.) Linux
+      FreeS/WAN will then enable forwarding when starting up and turn it off
+      when going down. This is used to ensure that no packets will be
+      forwarded before IPsec comes up and takes control.</dd>
+  <dt>syslog=daemon.error</dt>
+    <dd>Used in messages to the system logging daemon (syslogd) to specify
+      what type of software is sending the messages. If the settings are
+      "daemon.error" as in our example, then syslogd treats the messages as
+      error messages from a daemon.
+      <p>Note that <a href="glossary.html#Pluto">Pluto</a> does not currently
+      pay attention to this variable. The variable controls setup messages
+      only.</p>
+    </dd>
+  <dt>klipsdebug=</dt>
+    <dd>Debug settings for <a href="glossary.html#KLIPS">KLIPS</a>.</dd>
+  <dt>plutodebug=</dt>
+    <dd>Debug settings for <a href="glossary.html#Pluto">Pluto</a>.</dd>
+  <dt>... for both the above DEBUG settings</dt>
+    <dd>Normally, leave empty as shown above for no debugging output.<br>
+      Use "all" for maximum information.<br>
+      See ipsec_klipsdebug(8) and ipsec_pluto(8) man page for other options.
+      Beware that if you set /etc/ipsec.conf to enable debug output, your
+      system's log files may get large quickly.</dd>
+  <dt>dumpdir=/safe/directory</dt>
+    <dd>Normally, programs started by ipsec setup don't crash. If they do, by
+      default, no core dump will be produced because such dumps would contain
+      secrets. If you find you need to debug such crashes, you can set
+      dumpdir to the name of a directory in which to collect the core
+    file.</dd>
+  <dt>manualstart=</dt>
+    <dd>List of manually keyed connections to be automatically started at
+      boot time. Useful for testing, but not for long term use. Connections
+      which are automatically started should also be automatically
+    re-keyed.</dd>
+  <dt>pluto=yes</dt>
+    <dd>Whether to start <a href="glossary.html#Pluto">Pluto</a> when ipsec
+      startup is done.<br>
+      This parameter is optional and defaults to "yes" if not present.
+      <p>"yes" is strongly recommended for production use so that the keying
+      daemon (Pluto) will automatically re-key the connections regularly. The
+      ipsec-auto parameters ikelifetime, ipseclifetime and reykeywindow give
+      you control over frequency of rekeying.</p>
+    </dd>
+  <dt>plutoload="reno-van reno-adam reno-nyc"</dt>
+    <dd>List of tunnels (by name, e.g. fred-susan or reno-van in our
+      examples) to be loaded into Pluto's internal database at startup. In
+      this example, Pluto loads three tunnels into its database when it is
+      started.
+      <p>If plutoload is "%search", Pluto will load any connections whose
+      description includes "auto=add" or "auto=start".</p>
+    </dd>
+  <dt>plutostart="reno-van reno-adam reno-nyc"</dt>
+    <dd>List of tunnels to attempt to negotiate when Pluto is started.
+      <p>If plutostart is "%search", Pluto will start any connections whose
+      description includes "auto=start".</p>
+      <p>Note that, for a connection intended to be permanent, <strong>both
+      gateways should be set try to start</strong> the tunnel. This allows
+      quick recovery if either gateway is rebooted or has its IPsec
+      restarted. If only one gateway is set to start the tunnel and the other
+      gateway restarts, the tunnel may not be rebuilt.</p>
+    </dd>
+  <dt>plutowait=no</dt>
+    <dd>Controls whether Pluto waits for one tunnel to be established before
+      starting to negotiate the next. You might set this to "yes"
+      <ul>
+        <li>if your gateway is a very limited machine and you need to
+          conserve resources.</li>
+        <li>for debugging; the logs are clearer if only one connection is
+          brought up at a time</li>
+      </ul>
+      For a busy and resource-laden production gateway, you likely want "no"
+      so that connections are brought up in parallel and the whole process
+      takes less time.</dd>
+</dl>
+
+<p>The example assumes you are at the Reno office and will use IPsec to
+Vancouver, New York City and Amsterdam.</p>
+
+<h2><a name="multitunnel">Multiple tunnels between the same two
+gateways</a></h2>
+
+<p>Consider a pair of subnets, each with a security gateway, connected via
+the Internet:</p>
+<pre>         192.168.100.0/24           left subnet
+              |
+         192.168.100.1
+         North Gateway
+         101.101.101.101            left
+              |
+         101.101.101.1              left next hop
+         [Internet]
+         202.202.202.1              right next hop
+              |
+         202.202.202.202            right
+         South gateway
+         192.168.200.1
+              |
+         192.168.200.0/24           right subnet</pre>
+
+<p>A tunnel specification such as:</p>
+<pre>conn northnet-southnet
+      left=101.101.101.101
+      leftnexthop=101.101.101.1
+      leftsubnet=192.168.100.0/24
+      leftfirewall=yes
+      right=202.202.202.202
+      rightnexthop=202.202.202.1
+      rightsubnet=192.168.200.0/24
+      rightfirewall=yes</pre>
+will allow machines on the two subnets to talk to each other. You might test
+this by pinging from polarbear (192.168.100.7) to penguin (192.168.200.5).
+
+<p>However, <strong>this does not cover other traffic you might want to
+secure</strong>. To handle all the possibilities, you might also want these
+connection descriptions:</p>
+<pre>conn northgate-southnet
+      left=101.101.101.101
+      leftnexthop=101.101.101.1
+      right=202.202.202.202
+      rightnexthop=202.202.202.1
+      rightsubnet=192.168.200.0/24
+      rightfirewall=yes
+
+conn northnet-southgate
+      left=101.101.101.101
+      leftnexthop=101.101.101.1
+      leftsubnet=192.168.100.0/24
+      leftfirewall=yes
+      right=202.202.202.202
+      rightnexthop=202.202.202.1</pre>
+
+<p>Without these, neither gateway can do IPsec to the remote subnet. There is
+no IPsec tunnel or eroute set up for the traffic.</p>
+
+<p>In our example, with the non-routable 192.168.* addresses used, packets
+would simply be discarded. In a different configuration, with routable
+addresses for the remote subnet, <strong>they would be sent
+unencrypted</strong> since there would be no IPsec eroute and there would be
+a normal IP route.</p>
+
+<p>You might also want:</p>
+<pre>conn northgate-southgate
+      left=101.101.101.101
+      leftnexthop=101.101.101.1
+      right=202.202.202.202
+      rightnexthop=202.202.202.1</pre>
+
+<p>This is required if you want the two gateways to speak IPsec to each
+other.</p>
+
+<p>This requires a lot of duplication of details.  Judicious use of
+<var>also=</var> and <var>include</var> can reduce this problem.</p>
+
+<p>Note that, while FreeS/WAN supports all four tunnel types, not all
+implementations do. In particular, some versions of Windows 2000 and the
+freely downloadable version of PGP provide only "client" functionality. You
+cannot use them as gateways with a subnet behind them. To get that
+functionality, you must upgrade to Windows 2000 server or the commercially
+available PGP products.</p>
+
+<h3><a name="advroute">One tunnel plus advanced routing</a></h3>
+It is also possible to use the new routing features in 2.2 and later kernels
+to avoid most needs for multple tunnels. Here is one mailing list message on
+the topic:
+<pre>Subject: Re: linux-ipsec: IPSec packets not entering tunnel?
+   Date: Mon, 20 Nov 2000
+   From: Justin Guyett &lt;jfg@sonicity.com&gt;
+
+On Mon, 20 Nov 2000, Claudia Schmeing wrote:
+
+&gt; Right                                                         Left
+&gt;                      "home"                "office"
+&gt; 10.92.10.0/24 ---- 24.93.85.110 ========= 216.175.164.91 ---- 10.91.10.24/24
+&gt;
+&gt; I've created all four tunnels, and can ping to test each of them,
+&gt; *except* homegate-officenet.
+
+I keep wondering why people create all four tunnels.  Why not route
+traffic generated from home to 10.91.10.24/24 out ipsec0 with iproute2?
+And 99% of the time you don't need to access "office" directly, which
+means you can eliminate all but the subnet&lt;-&gt;subnet connection.</pre>
+and FreeS/WAN technical lead Henry Spencer's comment:
+<pre>&gt; I keep wondering why people create all four tunnels.  Why not route
+&gt; traffic generated from home to 10.91.10.24/24 out ipsec0 with iproute2?
+
+This is feasible, given some iproute2 attention to source addresses, but
+it isn't something we've documented yet... (partly because we're still
+making some attempt to support 2.0.xx kernels, which can't do this, but
+mostly because we haven't caught up with it yet).
+
+&gt; And 99% of the time you don't need to access "office" directly, which
+&gt; means you can eliminate all but the subnet&lt;-&gt;subnet connection.
+
+Correct in principle, but people will keep trying to ping to or from the
+gateways during testing, and sometimes they want to run services on the
+gateway machines too.</pre>
+
+
+<!-- Is this in the right spot in this document? -->
+<H2><A name="opp.gate">An Opportunistic Gateway</A></H2>
+                                                                                
+<H3>Start from full opportunism</H3>
+                                                                                
+<P>Full opportunism
+allows you to initiate and receive opportunistic connections on your
+machine. The remaining instructions in this section assume
+you have first set up full opportunism on your gateway using
+<A HREF="quickstart.html#opp.incoming">these instructions</A>.
+Both sets of instructions require mailing DNS records to your ISP. Collect
+DNS records for both the gateway (above) and the
+subnet nodes (below) before contacting your ISP.</P>
+                                                                                
+                                                                                
+<H3>Reverse DNS TXT records for each protected machine</H3>
+                                                                                
+<P>You need these so that your Opportunistic peers can:
+<UL>
+<LI>discover the gateway's address, knowing only the IP address
+ that packets are bound for</LI>
+<LI>verify that the gateway is authorised to encrypt for that endpoint</LI>
+</UL>
+                                                                                
+<P>On the gateway, generate a TXT record with:
+<PRE>    ipsec showhostkey --txt 192.0.2.11</PRE>
+<P>Use your gateway address in place of 192.0.2.11.</P>
+                                                                                
+<P>You should see (keys are trimmed for clarity throughout our example):</P>
+<PRE>    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;</PRE>
+                                                                                
+<P><B>This MUST BE the same key as in your gateway's TXT record, or nothing
+will work.</B></P>
+                                                                                
+<P>In a text file, make one copy of this TXT record for each subnet
+  node:</P>
+<PRE>    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;
+                                                                                
+    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;
+                                                                                
+    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;</PRE>
+                                                                                
+<P>Above each entry, insert a line like this:</P>
+<PRE>    98.2.0.192.in-addr.arpa. IN PTR arthur.example.com.</PRE>
+                                                                                
+<P>It must include:</P>
+<UL>
+<LI>The subnet node's address in reverse map format. For example, 192.0.2.120
+becomes <VAR>120.2.0.192.in-addr.arpa.</VAR>.  Note the final period.</LI>
+<LI><VAR>IN PTR</VAR></LI>
+<LI>The node's name, ie. <VAR>arthur.example.com.</VAR>. Note
+the final period.</LI>
+</UL>
+                                                                                
+<P>The result will be a file of TXT records, like this:</P>
+<PRE>    98.2.0.192.in-addr.arpa. IN PTR arthur.example.com.
+    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;
+                                                                                
+    99.2.0.192.in-addr.arpa. IN PTR ford.example.com.
+    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;
+                                                                                
+    100.2.0.192.in-addr.arpa. IN PTR trillian.example.com.
+    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;</PRE>
+                                                                                
+                                                                                
+<H3>Publish your records</H3>
+                                                                                
+<P>Ask your ISP to publish all the reverse DNS records you have collected.
+There may be a delay of up to 48 hours as the records propagate.</P>
+                                                                                
+                                                                                
+<H3>...and test them</H3>
+                                                                                
+<P>Check a couple of records with commands like this one:</P>
+                                                                                
+<PRE>    ipsec verify --host ford.example.com
+    ipsec verify --host trillian.example.com</PRE>
+                                                                                
+<P>The <var>verify</var> command checks for TXT records for both the
+subnet host and its gateway. You should see output like:</P>
+<PRE>    ...
+    Looking for TXT in reverse map: 99.2.0.192.in-addr.arpa [OK]
+    ...
+    Looking for TXT in reverse map: 11.2.0.192.in-addr.arpa   [OK]
+    ...
+    Looking for TXT in reverse map: 100.2.0.192.in-addr.arpa [OK]
+    ...
+    Looking for TXT in reverse map: 11.2.0.192.in-addr.arpa   [OK]
+    ...</PRE>
+<H3>No Configuration Needed</H3>
+                                                                                
+<P>FreeS/WAN 2.x ships with a built-in, automatically
+enabled OE connection <VAR>conn packetdefault</VAR>
+which applies OE, if possible, to all outbound traffic routed
+through the FreeS/WAN box.
+                                                                                
+The
+<A HREF="manpage.d/ipsec.conf.5.html">ipsec.conf(5) manual</A>
+describes this connection in detail.
+While the effect is much the same as <VAR>private-or-clear</VAR>,
+the implementation is different: notably, it does not use policy
+groups.</P>
+                                                                                
+<P>You can create more complex OE configurations
+for traffic forwarded through a FreeS/WAN box, as explained in our
+<A HREF="policygroups.html#policygroups">policy groups document</A>,
+or disable OE using
+<A HREF="policygroups.html#disable_policygroups">these instructions</A>.</P>
+
+
+
+<h2><a name="extruded.config">Extruded Subnets</a></h2>
+
+<p>What we call <a href="glossary.html#extruded">extruded subnets</a> are a
+special case of <a href="glossary.html#VPN.gloss">VPNs</a>.</p>
+
+<p>If your buddy has some unused IP addresses, in his subnet far off at the
+other side of the Internet, he can loan them to you... provided that the
+connection between you and him is fast enough to carry all the traffic
+between your machines and the rest of the Internet.  In effect, he "extrudes"
+a part of his address space over the network to you, with your Internet
+traffic appearing to originate from behind his Internet gateway.</p>
+
+<p>As far as the Internet is concerned, your new extruded net is behind your
+buddy's gateway. You route all your packets for the Internet at large
+out his gateway, and receive return packets the same way. You route your
+local packets locally.</p>
+
+<p>Suppose your friend has a.b.c.0/24 and wants to give you a.b.c.240/28. The
+initial situation is:</p>
+<pre>    subnet           gateway          Internet
+  a.b.c.0/24    a.b.c.1    p.q.r.s</pre>
+where anything from the Internet destined for any machine in a.b.c.0/24 is
+routed via p.q.r.s and that gateway knows what to do from there.
+
+<p>Of course it is quite normal for various smaller subnets to exist behind
+your friend's gateway. For example, your friend's company might have
+a.b.c.16/28=development, a.b.c.32/28=marketing and so on. The Internet
+neither knows not cares about this; it just delivers packets to the p.q.r.s
+and lets the gateway do whatever needs to be done from there.</p>
+
+<p>What we want to do is take a subnet, perhaps a.b.c.240/28, out of your
+friend's physical location <em>while still having your friend's gateway route
+to it</em>. As far as the Internet is concerned, you remain behind that
+gateway.</p>
+<pre>    subnet           gateway          Internet       your gate  extruded
+
+  a.b.c.0/24   a.b.c.1     p.q.r.s              d.e.f.g         a.b.c.240/28                
+
+                           ========== tunnel ==========</pre>
+
+<p>The extruded addresses have to be a complete subnet.</p>
+
+<p>In our example, the friend's security gateway is also his Internet
+gateway, but this is not necessary. As long as all traffic from the Internet
+to his addresses passes through the Internet gate, the security gate could be
+a machine behind that. The IG would need to route all traffic for the
+extruded subnet to the SG, and the SG could handle the rest.</p>
+
+<p>First, configure your subnet using the extruded addresses.  Your security
+gateway's interface to your subnet needs to have an extruded address
+(possibly using a Linux <a href="glossary.html#virtual">virtual
+interface</a>, if it also has to have a different address). Your gateway
+needs to have a route to the extruded subnet, pointing to that interface. The
+other machines at your site need to have addresses in that subnet, and
+default routes pointing to your gateway.</p>
+
+<p>If any of your friend's machines need to talk to the extruded subnet,
+<em>they</em> need to have a route for the extruded subnet, pointing at his
+gateway.</p>
+
+<p>Then set up an IPsec subnet-to-subnet tunnel between your gateway and his,
+with your subnet specified as the extruded subnet, and his subnet specified
+as "0.0.0.0/0".</p>
+
+<p>The tunnel description should be:</p>
+<pre>conn extruded
+        left=p.q.r.s
+        leftsubnet=0.0.0.0/0
+        right=d.e.f.g
+        rightsubnet=a.b.c.0/28</pre>
+
+<p>If either side was doing firewalling for the extruded subnet before the
+IPsec connection is set up, you'll need to poke holes in your
+<A HREF="firewall.html#firewall">firewall</A> to allow packets through.
+</p>
+
+<p>And it all just works.  Your SG routes traffic for 0.0.0.0/0 -- that is,
+the whole Internet -- through the tunnel to his SG, which then sends it
+onward as if it came from his subnet.  When traffic for the extruded subnet
+arrives at his SG, it gets sent through the tunnel to your SG, which passes
+it to the right machine.</p>
+
+<p>Remember that when ipsec_manual or ipsec_auto takes a connection down, it
+<em>does not undo the route</em> it made for that connection. This lets you
+take a connection down and bring up a new one, or a modified version of the
+old one, without having to rebuild the route it uses and without any risk of
+packets which should use IPsec accidentally going out in the clear. Because
+the route always points into KLIPS, the packets will always go there. Because
+KLIPS temporarily has no idea what to do with them (no eroute for them), they
+will be discarded.</p>
+
+<p>If you <em>do</em> want to take the route down, this is what the "unroute"
+operation in manual and auto is for.  Just do an unroute after doing the
+down.</p>
+
+<p>Note that the route for a connection may have replaced an existing
+non-IPsec route. Nothing in Linux FreeS/WAN will put that pre-IPsec route
+back. If you need it back, you have to create it with the route command.</p>
+
+<h2><a name="roadvirt">Road Warrior with virtual IP address</a></h2>
+
+<p>Please note that <A HREF="http://www.freeswan.ca/download.php">Super
+FreeS/WAN</A> now features DHCP-over-IPsec, which is an alternate procedure 
+for Virtual IP address assignment.
+<p>
+
+<p>Here is a mailing list message about another way to configure for road
+warrior support:</p>
+<pre>Subject: Re: linux-ipsec: understanding the vpn
+   Date: Thu, 28 Oct 1999 10:43:22 -0400
+   From: Irving Reid &lt;irving@nevex.com&gt;
+
+&gt;  local-------linux------internet------mobile
+&gt;  LAN        box                         user
+&gt;  ...
+
+&gt;  now when the mobile user connects to the linux box
+&gt;  it is given a virtual IP address, i have configured it to
+&gt;  be in the 10.x.x.x range. mobile user and linux box 
+&gt;  have a tunnel between them with these IP addresses.
+
+&gt;   Uptil this all is fine.
+
+If it is possible to configure your mobile client software *not* to
+use a virtual IP address, that will make your life easier. It is easier
+to configure FreeS/WAN to use the actual address the mobile user gets
+from its ISP.
+
+Unfortunately, some Windows clients don't let you choose.
+
+&gt;  what i would like to know is that how does the mobile
+&gt;  user communicate with other computers on the local
+&gt;  LAN , of course with the vpn ?
+
+&gt;   what IP address should the local LAN 
+&gt;  computers have ? I guess their default gateway 
+&gt;  should be the linux box ? and does the linux box need
+&gt;  to be a 2 NIC card box or one is fine.
+
+As someone else stated, yes, the Linux box would usually be the default
+IP gateway for the local lan.
+
+However...
+
+If you mobile user has software that *must* use a virtual IP address,
+the whole picture changes. Nobody has put much effort into getting
+FreeS/WAN to play well in this environment, but here's a sketch of one
+approach:
+
+Local Lan 1.0.0.0/24
+    |
+    +- Linux FreeS/WAN 1.0.0.2
+    |
+    | 1.0.0.1
+ Router
+    | 2.0.0.1
+    |
+Internet
+    |
+    | 3.0.0.1
+Mobile User
+      Virtual Address: 1.0.0.3
+
+Note that the Local Lan network (1.0.0.x) can be registered, routable
+addresses.
+
+Now, the Mobile User sets up an IPSec security association with the
+Linux box (1.0.0.2); it should ESP encapsulate all traffic to the
+network 1.0.0.x **EXCEPT** UDP port 500. 500/udp is required for the key
+negotiation, which needs to work outside of the IPSec tunnel.
+
+On the Linux side, there's a bunch of stuff you need to do by hand (for
+now). FreeS/WAN should correctly handle setting up the IPSec SA and
+routes, but I haven't tested it so this may not work...
+
+The FreeS/WAN conn should look like:
+
+conn mobile
+        right=1.0.0.2
+        rightsubnet=1.0.0.0/24
+        rightnexthop=1.0.0.1
+        left=0.0.0.0  # The infamous "road warrior"
+        leftsubnet=1.0.0.3/32
+
+Note that the left subnet contains *only* the remote host's virtual
+address.
+
+Hopefully the routing table on the FreeS/WAN box ends up looking like
+this:
+
+% netstat -rn
+Kernel IP routing table
+Destination     Gateway      Genmask         Flags   MSS Window  irtt Iface
+1.0.0.0         0.0.0.0      255.255.255.0   U      1500 0          0 eth0
+127.0.0.0       0.0.0.0      255.0.0.0       U      3584 0          0 lo
+0.0.0.0         1.0.0.1      0.0.0.0         UG     1500 0          0 eth0
+1.0.0.3         1.0.0.1      255.255.255.255 UG     1433 0          0 ipsec0
+
+So, if anybody sends a packet for 1.0.0.3 to the Linux box, it should
+get bundled up and sent through the tunnel. To get the packets for
+1.0.0.3 to the Linux box in the first place, you need to use "proxy
+ARP".
+
+How this works is: when a host or router on the local Ethernet segment
+wants to send a packet to 1.0.0.3, it sends out an Ethernet level
+broadcast "ARP request". If 1.0.0.3 was on the local LAN, it would
+reply, saying "send IP packets for 1.0.0.3 to my Ethernet address".
+
+Instead, you need to set up the Linux box so that _it_ answers ARP
+requests for 1.0.0.3, even though that isn't its IP address. That
+convinces everyone else on the lan to send 1.0.0.3 packets to the Linux
+box, where the usual FreeS/WAN processing and routing take over.
+
+% arp -i eth0 -s 1.0.0.3 -D eth0 pub
+
+This says, if you see an ARP request on interface eth0 asking for
+1.0.0.3, respond with the Ethernet address of interface eth0.
+
+Now, as I said at the very beginning, if it is *at all* possible to
+configure your client *not* to use the virtual IP address, you can avoid
+this whole mess.</pre>
+
+<h2><a name="dynamic">Dynamic Network Interfaces</a></h2>
+
+<p>Sometimes you have to cope with a situation where the network interface(s)
+aren't all there at boot. The common example is notebooks with PCMCIA.</p>
+
+<h3><a name="basicdyn">Basics</a></h3>
+
+<p>The key issue here is that the <var>config setup</var> section of the
+<var>/etc/ipsec.conf</var> configuration file lists the connection between
+ipsecN and hardware interfaces, in the <var>interfaces=</var> variable. At
+any time when <var>ipsec setup start</var> or <var>ipsec setup restart</var>
+is run this variable <strong>must</strong> correspond to the current real
+situation. More precisely, it <strong>must not</strong> mention any hardware
+interfaces which don't currently exist. The difficulty is that an <var>ipsec
+setup start</var> command is normally run at boot time so interfaces that are
+not up then are mis-handled.</p>
+
+<h3><a name="bootdyn">Boot Time</a></h3>
+
+<p>Normally, an <var>ipsec setup start</var> is run at boot time. However, if
+the hardware situation at boot time is uncertain, one of two things must be
+done.</p>
+<ul>
+  <li>One possibility is simply not to have IPsec brought up at boot time. To
+    do this:
+    <pre>        chkconfig --level 2345 ipsec off</pre>
+    That's for modern Red Hats or other Linuxes with chkconfig. Systems which
+    lack this will require fiddling with symlinks in /etc/rc.d/rc?.d or the
+    equivalent.</li>
+  <li>Another possibility is to bring IPsec up with no interfaces, which is
+    less aesthetically satisfying but simpler.  Just put
+    <pre>        interfaces=</pre>
+    in the configuration file.  KLIPS and Pluto will be started, but won't do
+    anything.</li>
+</ul>
+
+<h3><a name="changedyn">Change Time</a></h3>
+
+<p>When the hardware *is* in place, IPsec has to be made aware of it. Someday
+there may be a nice way to do this.</p>
+
+<p>Right now, the way to do it is to fix the <var>/etc/ipsec.conf</var> file
+appropriately, so <var>interfaces</var> reflects the new situation, and then
+restart the IPsec subsystem. This does break any existing IPsec
+connections.</p>
+
+<p>If IPsec wasn't brought up at boot time, do</p>
+<pre>        ipsec setup start</pre>
+while if it was, do
+<pre>        ipsec setup restart</pre>
+which won't be as quick.
+
+<p>If some of the hardware is to be taken out, before doing that, amend the
+configuration file so interfaces no longer includes it, and do</p>
+<pre>        ipsec setup restart</pre>
+
+<p>Again, this breaks any existing connections.</p>
+
+<h2><a name="unencrypted">Unencrypted tunnels</a></h2>
+
+<p>Sometimes you might want to create a tunnel without encryption. Often this
+is a bad idea, even if you have some data which need not be private. See this
+<a href="ipsec.html#traffic.resist">discussion</a>.</p>
+
+<p>The IPsec protocols provide two ways to do build such tunnels:</p>
+<dl>
+  <dt>using ESP with null encryption</dt>
+    <dd>not supported by FreeS/WAN</dd>
+  <dt>using <a href="glossary.html#AH">AH</a> without <a
+  href="glossary.html#ESP">ESP</a></dt>
+    <dd>supported for manually keyed connections</dd>
+    <dd>possible with explicit commands via <a
+      href="manpage.d/ipsec_whack.8.html">ipsec_whack(8)</a> (see this <a
+      href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/02/msg00190.html">list
+      message</a>)</dd>
+    <dd>not supported in the <a
+      href="manpage.d/ipsec_auto.8.html">ipsec_auto(8)</a> scripts.</dd>
+</dl>
+One situation in which this comes up is when otherwise some data would be
+encrypted twice. Alice wants a secure tunnel from her machine to Bob's. Since
+she's behind one security gateway and he's behind another, part of the tunnel
+that they build passes through the tunnel that their site admins have built
+between the gateways. All of Alice and Bob's messages are encrypted twice.
+
+<p>There are several ways to handle this.</p>
+<ul>
+  <li>Just accept the overhead of double encryption. The site admins might
+    choose this if any of the following apply:
+    <ul>
+      <li>policy says encrypt everything (usually, it should)</li>
+      <li>they don't entirely trust Alice and Bob (usually, if they don't
+        have to, they shouldn't)</li>
+      <li>if they don't feel the saved cycles are worth the time they'd need
+        to build a non-encrypted tunnel for Alice and Bob's packets (often,
+        they aren't)</li>
+    </ul>
+  </li>
+  <li>Use a plain IP-in-IP tunnel. These are not well documented. A good
+    starting point is in the Linux kernel source tree, in
+    /usr/src/linux/drivers/net/README.tunnel.</li>
+  <li>Use a manually-keyed AH-only tunnel.</li>
+</ul>
+
+<p>Note that if Alice and Bob want end-to-end security, they must build a
+tunnel end-to-end between their machines or use some other end-to-end tool
+such as PGP or SSL that suits their data. The only question is whether the
+admins build some special unencrypted tunnel for those already-encrypted
+packets.</p>
+</body>
+</html>
diff --git a/doc/src/background.html b/doc/src/background.html
new file mode 100644
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+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>FreeS/WAN background</title>
+  <meta name="keywords" content="Linux, IPSEC, VPN, security, FreeSWAN">
+  <!--
+
+  Written by Sandy Harris for the Linux FreeS/WAN project
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: background.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+
+<body>
+<h1><a name="background">Linux FreeS/WAN background</a></h1>
+
+<p>This section discusses a number of issues which have three things in
+common:</p>
+<ul>
+  <li>They are not specifically FreeS/WAN problems</li>
+  <li>You may have to understand them to get FreeS/WAN working right</li>
+  <li>They are not simple questions</li>
+</ul>
+
+<p>Grouping them here lets us provide the explanations some users will need
+without unduly complicating the main text.</p>
+
+<p>The explanations here are intended to be adequate for FreeS/WAN purposes
+(please comment to the <a href="mail.html">users mailing list</a> if you
+don't find them so), but they are not trying to be complete or definitive. If
+you need more information, see the references provided in each section.</p>
+
+<h2><a name="dns.background">Some DNS background</a></h2>
+
+<p><a href="glossary.html#carpediem">Opportunistic encryption</a> requires
+that the gateway systems be able to fetch public keys, and other
+IPsec-related information, from each other's DNS (Domain Name Service)
+records.</p>
+
+<p><a href="glossary.html#DNS">DNS</a> is a distributed database that maps
+names to IP addresses and vice versa.</p>
+
+<p>Much good reference material is available for DNS, including:</p>
+<ul>
+  <li>the <a href="http://www.linuxdoc.org/HOWTO/DNS-HOWTO.html">DNS
+  HowTo</a></li>
+  <li>the standard <a href="biblio.html#DNS.book">DNS reference</a> book</li>
+  <li><a href="http://www.linuxdoc.org/LDP/nag2/index.html">Linux Network
+    Administrator's Guide</a></li>
+  <li><a
+    href="http://www.nominum.com/resources/whitepapers/bind-white-paper.html">BIND
+    overview</a></li>
+  <li><a
+    href="http://www.nominum.com/resources/documentation/Bv9ARM.pdf">BIND 9
+    Administrator's Reference</a></li>
+</ul>
+
+<p>We give only a brief overview here, intended to help you use DNS for
+FreeS/WAN purposes.</p>
+
+<h3><a name="forward.reverse">Forward and reverse maps</a></h3>
+
+<p>Although the implementation is distributed, it is often useful to speak of
+DNS as if it were just two enormous tables:</p>
+<ul>
+  <li>the forward map: look up a name, get an IP address</li>
+  <li>the reverse map: look up an IP address, get a name</li>
+</ul>
+
+<p>Both maps can optionally contain additional data. For opportunistic
+encryption, we insert the data need for IPsec authentication.</p>
+
+<p>A system named gateway.example.com with IP address 10.20.30.40 should have
+at least two DNS records, one in each map:</p>
+<dl>
+  <dt>gateway.example.com. IN A 10.20.30.40</dt>
+    <dd>used to look up the name and get an IP address</dd>
+  <dt>40.30.20.10.in-addr.arpa. IN PTR gateway.example.com.</dt>
+    <dd>used for reverse lookups, looking up an address to get the associated
+      name. Notice that the digits here are in reverse order; the actual
+      address is 10.20.30.40 but we use 40.30.20.10 here.</dd>
+</dl>
+
+<h3>Hierarchy and delegation</h3>
+
+<p>For both maps there is a hierarchy of DNS servers and a system of
+delegating authority so that, for example:</p>
+<ul>
+  <li>the DNS administrator for example.com can create entries of the form
+    <var>name</var>.example.com</li>
+  <li>the example.com admin cannot create an entry for counterexample.com;
+    only someone with authority for .com can do that</li>
+  <li>an admin might have authority for 20.10.in-addr.arpa.</li>
+  <li>in either map, authority can be delegated
+    <ul>
+      <li>the example.com admin could give you authority for
+        westcoast.example.com</li>
+      <li>the 20.10.in-addr.arpa admin could give you authority for
+        30.20.10.in-addr.arpa</li>
+    </ul>
+  </li>
+</ul>
+
+<p>DNS zones are the units of delegation. There is a hierarchy of zones.</p>
+
+<h3>Syntax of DNS records</h3>
+
+<p>Returning to the example records:</p>
+<pre>        gateway.example.com. IN A 10.20.30.40
+        40.30.20.10.in-addr.arpa. IN PTR gateway.example.com.</pre>
+
+<p>some syntactic details are:</p>
+<ul>
+  <li>the IN indicates that these records are for <strong>In</strong>ternet
+    addresses</li>
+  <li>The final periods in '.com.' and '.arpa.' are required. They indicate
+    the root of the domain name system.</li>
+</ul>
+
+<p>The capitalised strings after IN indicate the type of record. Possible
+types include:</p>
+<ul>
+  <li><strong>A</strong>ddress, for forward lookups</li>
+  <li><strong>P</strong>oin<strong>T</strong>e<strong>R</strong>, for reverse
+    lookups</li>
+  <li><strong>C</strong>anonical <strong>NAME</strong>, records to support
+    aliasing, multiple names for one address</li>
+  <li><strong>M</strong>ail e<strong>X</strong>change, used in mail
+  routing</li>
+  <li><strong>SIG</strong>nature, used in <a href="glossary.html#SDNS">secure
+    DNS</a></li>
+  <li><strong>KEY</strong>, used in <a href="glossary.html#SDNS">secure
+    DNS</a></li>
+  <li><strong>T</strong>e<strong>XT</strong>, a multi-purpose record type</li>
+</ul>
+
+<p>To set up for opportunistic encryption, you add some TXT records
+to your DNS data. Details are in our <a href="quickstart.html">quickstart</a>
+document.</p>
+
+<h3>Cacheing, TTL and propagation delay</h3>
+
+<p>DNS information is extensively cached. With no caching, a lookup by your
+system of "www.freeswan.org" might involve:</p>
+<ul>
+  <li>your system asks your nameserver for "www.freeswan.org"</li>
+  <li>local nameserver asks root server about ".org", gets reply</li>
+  <li>local nameserver asks .org nameserver about "freeswan.org", gets
+  reply</li>
+  <li>local nameserver asks freeswan.org nameserver about "www.freeswan.org",
+    gets reply</li>
+</ul>
+
+<p>However, this can be a bit inefficient. For example, if you are in the
+Phillipines, the closest a root server is in Japan. That might send you to a
+.org server in the US, and then to freeswan.org in Holland. If everyone did
+all those lookups every time they clicked on a web link, the net would grind
+to a halt.</p>
+
+<p>Nameservers therefore cache information they look up. When you click on
+another link at www.freeswan.org, your local nameserver has the IP address
+for that server in its cache, and no further lookups are required. </p>
+
+<p>Intermediate results are also cached. If you next go to
+lists.freeswan.org, your nameserver can just ask the freeswan.org nameserver
+for that address; it does not need to query the root or .org nameservers
+because it has a cached address for the freeswan.org zone server.</p>
+
+<p>Of course, like any cacheing mechanism, this can create problems of
+consistency. What if the administrator for freeswan.org changes the IP
+address, or the authentication key, for www.freeswan.org? If you use old
+information from the cache, you may get it wrong. On the other hand, you
+cannot afford to look up fresh information every time. Nor can you expect the
+freeswan.org server to notify you; that isn't in the protocols.</p>
+
+<p>The solution that is in the protocols is fairly simple. Cacheable records
+are marked with Time To Live (TTL) information. When the time expires, the
+caching server discards the record. The next time someone asks for it, the
+server fetches a fresh copy. Of course, a server may also discard records
+before their TTL expires if it is running out of cache space.</p>
+
+<p>This implies that there will be some delay before the new version of a
+changed record propagates around the net. Until the TTLs on all copies of the
+old record expire, some users will see it because that is what is in their
+cache. Other users may see the new record immediately because they don't have
+an old one cached.</p>
+
+<h2><a name="MTU.trouble">Problems with packet fragmentation</a></h2>
+
+<p>It seems, from mailing list reports, to be moderately common for problems
+to crop up in which small packets pass through the IPsec tunnels just fine
+but larger packets fail.</p>
+
+<p>These problems are caused by various devices along the way mis-handling
+either packet fragments or <a href="glossary.html#pathMTU">path MTU
+discovery</a>.</p>
+
+<p>IPsec makes packets larger by adding an ESP or AH header. This can tickle
+assorted bugs in fragment handling in routers and firewalls, or in path MTU
+discovery mechanisms, and cause a variety of symptoms which are both annoying
+and, often, quite hard to diagnose.</p>
+
+<p>An explanation from project technical lead Henry Spencer:</p>
+<pre>The problem is IP fragmentation; more precisely, the problem is that the
+second, third, etc. fragments of an IP packet are often difficult for
+filtering mechanisms to classify.
+
+Routers cannot rely on reassembling the packet, or remembering what was in
+earlier fragments, because the fragments may be out of order or may even
+follow different routes.  So any general, worst-case filtering decision
+pretty much has to be made on each fragment independently.  (If the router
+knows that it is the only route to the destination, so all fragments
+*must* pass through it, reassembly would be possible... but most routers
+don't want to bother with the complications of that.)
+
+All fragments carry roughly the original IP header, but any higher-level
+header is (for IP purposes) just the first part of the packet data... so
+only the first fragment carries that.  So, for example, on examining the
+second fragment of a TCP packet, you could tell that it's TCP, but not
+what port number it is destined for -- that information is in the TCP
+header, which appears in the first fragment only. 
+
+The result of this classification difficulty is that stupid routers and
+over-paranoid firewalls may just throw fragments away.  To get through
+them, you must reduce your MTU enough that fragmentation will not occur.
+(In some cases, they might be willing to attempt reassembly, but have very
+limited resources to devote to it, meaning that packets must be small and
+fragments few in number, leading to the same conclusion:  smaller MTU.)</pre>
+
+<p>In addition to the problem Henry describes, you may also have trouble with
+<a href="glossary.html#pathMTU">path MTU discovery</a>.</p>
+
+<p>By default, FreeS/WAN uses a large <a href="glossary.html#MTU">MTU</a> for
+the ipsec device. This avoids some problems, but may complicate others.
+Here's an explanation from Claudia:</p>
+<pre>Here are a couple of pieces of background information. Apologies if you
+have seen these already. An excerpt from one of my old posts:
+
+    An MTU of 16260 on ipsec0 is usual. The IPSec device defaults to this 
+    high MTU so that it does not fragment incoming packets before encryption 
+    and encapsulation. If after IPSec processing packets are larger than 1500,
+    [ie. the mtu of eth0] then eth0 will fragment them. 
+
+    Adding IPSec headers adds a certain number of bytes to each packet. 
+    The MTU of the IPSec interface refers to the maximum size of the packet
+    before the IPSec headers are added. In some cases, people find it helpful 
+    to set ipsec0's MTU to 1500-(IPSec header size), which IIRC is about 1430.
+
+    That way, the resulting encapsulated packets don't exceed 1500. On most 
+    networks, packets less than 1500 will not need to be fragmented.
+
+and... (from Henry Spencer)
+
+    The way it *ought* to work is that the MTU advertised by the ipsecN
+    interface should be that of the underlying hardware interface, less a
+    pinch for the extra headers needed. 
+
+    Unfortunately, in certain situations this breaks many applications.
+    There is a widespread implicit assumption that the smallest MTUs are 
+    at the ends of paths, not in the middle, and another that MTUs are 
+    never less than 1500.  A lot of code is unprepared to handle paths 
+    where there is an "interior minimum" in the MTU, especially when it's 
+    less than 1500. So we advertise a big MTU and just let the resulting 
+    big packets fragment.
+
+This usually works, but we do get bitten in cases where some intermediate
+point can't handle all that fragmentation.  We can't win on this one.</pre>
+
+<p>The MTU can be changed with an <var>overridemtu=</var> statement in the
+<var>config setup</var> section of <a
+href="manpage.d/ipsec.conf.5.html">ipsec.conf.5</a>.</p>
+
+<p>For a discussion of MTU issues and some possible solutions using Linux
+advanced routing facilities, see the <a
+href="http://www.linuxguruz.org/iptables/howto/2.4routing-15.html#ss15.6">Linux
+2.4 Advanced Routing HOWTO</a>.
+
+For a discussion of MTU and NAT (Network Address Translation), see
+<A HREF="http://harlech.math.ucla.edu/services/ipsec.html">James Carter's MTU
+notes</A>.</p>
+
+<h2><a name="nat.background">Network address translation (NAT)</a></h2>
+
+<p><strong>N</strong>etwork <strong>A</strong>ddress
+<strong>T</strong>ranslation is a service provided by some gateway machines.
+Calling it NAPT (adding the word  <strong>P</strong>ort) would be more
+precise, but we will follow the widespread usage.</p>
+
+<p>A gateway doing NAT rewrites the headers of packets it is forwarding,
+changing one or more of:</p>
+<ul>
+  <li>source address</li>
+  <li>source port</li>
+  <li>destination address</li>
+  <li>destination port</li>
+</ul>
+
+<p>On Linux 2.4, NAT services are provided by the <a
+href="http://netfilter.samba.org">netfilter(8)</a> firewall code. There are
+several <a
+href="http://netfilter.samba.org/documentation/index.html#HOWTO">Netfilter
+HowTos</a> including one on NAT.</p>
+
+<p>For older versions of Linux, this was referred to as "IP masquerade" and
+different tools were used. See this <a
+href="http://www.e-infomax.com/ipmasq/">resource page</a>.</p>
+
+<p>Putting an IPsec gateway behind a NAT gateway is not recommended. See our
+<a href="firewall.html#NAT">firewalls document</a>.</p>
+
+<h3>NAT to non-routable addresses</h3>
+
+<p>The most common application of NAT uses private <a
+href="glossary.html#non-routable">non-routable</a> addresses.</p>
+
+<p>Often a home or small office network will have:</p>
+<ul>
+  <li>one connection to the Internet</li>
+  <li>one assigned publicly visible IP address</li>
+  <li>several machines that all need access to the net</li>
+</ul>
+
+<p>Of course this poses a problem since several machines cannot use one
+address. The best solution might be to obtain more addresses, but often this
+is impractical or uneconomical.</p>
+
+<p>A common solution is to have:</p>
+<ul>
+  <li><a href="glossary.html#non-routable">non-routable</a> addresses on the
+    local network</li>
+  <li>the gateway machine doing NAT</li>
+  <li>all packets going outside the LAN rewritten to have the gateway as
+    their source address</li>
+</ul>
+
+<p>The client machines are set up with reserved <a
+href="#non-routable">non-routable</a> IP addresses defined in RFC 1918. The
+masquerading gateway, the machine with the actual link to the Internet,
+rewrites packet headers so that all packets going onto the Internet appear to
+come from one IP address, that of its Internet interface. It then gets all
+the replies, does some table lookups and more header rewriting, and delivers
+the replies to the appropriate client machines.</p>
+
+<p>As far as anyone else on the Internet is concerned, the systems behind the
+gateway are completely hidden. Only one machine with one IP address is
+visible.</p>
+
+<p>For IPsec on such a gateway, you can entirely ignore the NAT in:</p>
+<ul>
+  <li><a href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a></li>
+  <li>firewall rules affecting your Internet-side interface</li>
+</ul>
+
+<p>Those can be set up exactly as they would be if your gateway had no other
+systems behind it.</p>
+
+<p>You do, however, have to take account of the NAT in firewall rules which
+affect packet forwarding.</p>
+
+<h3>NAT to routable addresses</h3>
+
+<p>NAT to routable addresses is also possible, but is less common and may
+make for rather tricky routing problems. We will not discuss it here. See the
+<a href="http://netfilter.samba.org/documentation/index.html#HOWTO">Netfilter
+HowTos</a>.</p>
+</body>
+</html>
diff --git a/doc/src/biblio.html b/doc/src/biblio.html
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+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>FreeS/WAN bibliography</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, FreeSWAN, bibliography">
+  <!--
+
+  Written by Sandy Harris for the Linux FreeS/WAN project
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: biblio.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+
+<body>
+<h1><a name="biblio">Bibliography for the Linux FreeS/WAN project</a></h1>
+
+<p>For extensive bibliographic links, see the <a
+href="http://liinwww.ira.uka.de/bibliography/index.html">Collection of
+Computer Science Bibliographies</a></p>
+
+<p>See our <a href="web.html">web links</a> for material available online.</p>
+<hr>
+<a name="adams">Carlisle Adams and Steve Lloyd <cite>Understanding Public Key
+Infrastructure</cite><br>
+</a>Macmillan 1999 ISBN 1-57870-166-x
+
+<p>An overview, mainly concentrating on policy and strategic issues rather
+than the technical details. Both authors work for <a
+href="glossary.html#PKI">PKI</a> vendor <a
+href="http://www.entrust.com/">Entrust</a>.</p>
+<hr>
+<a name="DNS.book">Albitz, Liu &amp; Loukides <cite>DNS &amp; BIND</cite> 3rd
+edition<br>
+</a> O'Reilly 1998 ISBN 1-56592-512-2
+
+<p>The standard reference on the <a href="glossary.html#DNS">Domain Name
+Service</a> and <a href="glossary.html#BIND">Berkeley Internet Name
+Daemon</a>.</p>
+<hr>
+<a name="anderson">Ross Anderson</a>, <cite>Security Engineering - a Guide to
+Building Dependable Distributed Systems</cite><br>
+Wiley, 2001, ISBN 0471389226
+
+<p>Easily the best book for the security professional I have seen.
+<strong>Highly recommended</strong>. See the <a
+href="http://www.cl.cam.ac.uk/~rja14/book.html">book web page</a>.</p>
+
+<p>This is quite readable, but Schneier's <a href="#secrets">Secrets and
+Lies</a> might be an easier introduction.</p>
+<hr>
+<a name="puzzle">Bamford <cite>The Puzzle Palace, A report on NSA, Americas's
+most Secret Agency</cite><br>
+Houghton Mifflin 1982 ISBN 0-395-31286-8</a>
+<hr>
+Bamford <cite>Body of Secrets</cite>
+
+<p>The sequel.</p>
+<hr>
+<a name="bander">David Bander</a>, <cite>Linux Security Toolkit</cite><br>
+IDG Books, 2000, ISBN: 0764546902
+
+<p>This book has a short section on FreeS/WAN and includes Caldera Linux on
+CD.</p>
+<hr>
+<a name="CZR">Chapman, Zwicky &amp; Russell</a>, <cite>Building Internet
+Firewalls</cite><br>
+O'Reilly 1995 ISBN 1-56592-124-0
+<hr>
+<a name="firewall.book">Cheswick and Bellovin</a> <cite>Firewalls and
+Internet Security: Repelling the Wily Hacker</cite><br>
+Addison-Wesley 1994 ISBN 0201633574
+
+<p>A fine book on firewalls in particular and security in general from two of
+AT&amp;T's system adminstrators.</p>
+
+<p>Bellovin has also done a number of <a href="web.html#papers">papers</a> on
+IPsec and co-authored a <a href="intro.html#applied">paper</a> on a large
+FreeS/WAN application.</p>
+<hr>
+<a name="comer">Comer <cite>Internetworking with TCP/IP</cite><br>
+Prentice Hall</a>
+<ul>
+  <li>Vol. I: Principles, Protocols, &amp; Architecture, 3rd Ed. 1995
+    ISBN:0-13-216987-8</li>
+  <li>Vol. II: Design, Implementation, &amp; Internals, 2nd Ed. 1994
+    ISBN:0-13-125527-4</li>
+  <li>Vol. III: Client/Server Programming &amp; Applications
+    <ul>
+      <li>AT&amp;T TLI Version  1994 ISBN:0-13-474230-3</li>
+      <li>BSD Socket Version 1996 ISBN:0-13-260969-X</li>
+      <li>Windows Sockets Version 1997 ISBN:0-13-848714-6</li>
+    </ul>
+  </li>
+</ul>
+
+<p>If you need to deal with the details of the network protocols, read either
+this series or the <a href="#stevens">Stevens and Wright</a> series before
+you start reading the RFCs.</p>
+<hr>
+<a name="diffie">Diffie and Landau</a> <cite>Privacy on the Line: The
+Politics of Wiretapping and Encryption</cite><br>
+MIT press 1998 ISBN 0-262-04167-7 (hardcover) or 0-262-54100-9<br>
+
+<hr>
+<a name="d_and_hark">Doraswamy and Harkins <cite>IP Sec: The New Security
+Standard for the Internet, Intranets and Virtual Private Networks</cite><br>
+Prentice Hall 1999 ISBN: 0130118982</a>
+<hr>
+<a name="EFF"> Electronic Frontier Foundation <cite>Cracking DES: Secrets of
+Encryption Research, Wiretap Politics and Chip Design</cite><br>
+</a> O'Reilly 1998 ISBN 1-56592-520-3
+
+<p>To conclusively demonstrate that DES is inadequate for continued use, the
+<a href="glossary.html#EFF">EFF</a> built a machine for just over $200,000
+that breaks DES encryption in under five days on average, under nine in the
+worst case.</p>
+
+<p>The book provides details of their design and, perhaps even more
+important, discusses why they felt the project was necessary. Recommended for
+anyone interested in any of the three topics mentioned in the subtitle.</p>
+
+<p>See also the <a href="http://www.eff.org/descracker.html"> EFF page on
+this project </a> and our discussion of <a
+href="politics.html#desnotsecure">DES insecurity</a>.</p>
+<hr>
+Martin Freiss <cite>Protecting Networks with SATAN</cite><br>
+O'Reilly 1998 ISBN 1-56592-425-8<br>
+translated from a 1996 work in German
+
+<p>SATAN is a Security Administrator's Tool for Analysing Networks. This book
+is a tutorial in its use.</p>
+<hr>
+Gaidosch and Kunzinger<cite> A Guide to Virtual Private Networks</cite><br>
+Prentice Hall 1999 ISBN: 0130839647
+<hr>
+<a name="Garfinkel">Simson Garfinkel</a> <cite>Database Nation: the death of
+privacy in the 21st century</cite><br>
+O'Reilly 2000 ISBN 1-56592-653-6
+
+<p>A thoughtful and rather scary book.</p>
+<hr>
+<a name="PGP">Simson Garfinkel</a> <cite>PGP: Pretty Good Privacy</cite><br>
+O'Reilly 1995 ISBN 1-56592-098-8
+
+<p>An excellent introduction and user manual for the <a
+href="glossary.html#PGP">PGP</a> email-encryption package.  PGP is a good
+package with a complex and poorly-designed user interface. This book or one
+like it is a must for anyone who has to use it at length.</p>
+
+<p>The book covers using PGP in Unix, PC and Macintosh environments, plus
+considerable background material on both the technical and political issues
+around cryptography.</p>
+
+<p>The book is now seriously out of date. It does not cover recent
+developments such as commercial versions since PGP 5, the Open PGP standard
+or GNU PG..</p>
+<hr>
+<a name="practical">Garfinkel and Spafford</a> <cite>Practical Unix
+Security</cite><br>
+O'Reilly 1996 ISBN 1-56592-148-8
+
+<p>A standard reference.</p>
+
+<p>Spafford's web page has an excellent collection of<a
+href="http://www.cs.purdue.edu/coast/hotlist"> crypto and security
+links</a>.</p>
+<hr>
+<a name="Kahn">David Kahn</a> <cite>The Codebreakers: the Comprehensive
+History of Secret Communications from Ancient Times to the Internet</cite><br>
+second edition Scribner 1996 ISBN 0684831309
+
+<p>A history of codes and code-breaking from ancient Egypt to the 20th
+century. Well-written and exhaustively researched. <strong>Highly
+recommended</strong>, even though it does not have much on computer
+cryptography.</p>
+<hr>
+David Kahn <cite>Seizing the Enigma, The Race to Break the German U-Boat
+codes, 1939-1943</cite><br>
+Houghton Mifflin 1991 ISBN 0-395-42739-8
+<hr>
+<a name="kirch">Olaf Kirch</a> <cite>Linux Network Administrator's
+Guide</cite><br>
+O'Reilly 1995 ISBN 1-56592-087-2
+
+<p>Now becoming somewhat dated in places, but still a good introductory book
+and general reference.</p>
+<hr>
+<a name="LinVPN">Kolesnikov and Hatch</a>, <cite>Building Linux Virtual
+Private Networks (VPNs)</cite><br>
+New Riders 2002
+
+<p>This has had a number of favorable reviews, including <a
+href="http://www.slashdot.org/article.pl?sid=02/02/27/0115214&amp;mode=thread&amp;tid=172">this
+one</a> on Slashdot. The book has a <a
+href="http://www.buildinglinuxvpns.net/">web site</a>.</p>
+<hr>
+<a name="RFCs">Pete Loshin <cite>Big Book of IPsec RFCs</cite><br>
+Morgan Kaufmann 2000 ISBN: 0-12-455839-9</a>
+<hr>
+<a name="crypto">Steven Levy <cite>Crypto: How the Code Rebels Beat the
+Government -- Saving Privacy in the Digital Age</cite></a><br>
+Penguin 2001, ISBN 0-670--85950-8
+
+<p><strong>Highly recommended</strong>. A fine history of recent (about
+1970-2000) developments in the field, and the related political
+controversies. FreeS/WAN project founder and leader John Gilmore appears
+several times.</p>
+
+<p>The book does not cover IPsec or FreeS/WAN, but this project is very much
+another battle in the same war.  See our discussion of the <a
+href="politics.html">politics</a>.</p>
+<hr>
+<a name="GTR">Matyas, Anderson et al.</a> <cite>The Global Trust
+Register</cite><br>
+Northgate Consultants Ltd 1998 ISBN: 0953239705<br>
+hard cover edition MIT Press 1999 ISBN 0262511053
+
+<p>From<a href="http://www.cl.cam.ac.uk/Research/Security/Trust-Register">
+their web page:</a></p>
+
+<blockquote>
+  This book is a register of the fingerprints of the world's most important
+  public keys; it implements a top-level certification authority (CA) using
+  paper and ink rather than in an electronic system.</blockquote>
+<hr>
+<a name="handbook">Menezies, van Oorschot and Vanstone <cite>Handbook of
+Applied Cryptography</cite></a><br>
+CRC Press 1997<br>
+ISBN 0-8493-8523-7
+
+<p>An excellent reference. Read <a href="#schneier">Schneier</a> before
+tackling this.</p>
+<hr>
+Michael Padlipsky <cite>Elements of Networking Style</cite><br>
+Prentice-Hall 1985 ISBN 0-13-268111-0 or 0-13-268129-3
+
+<p>Probably <strong>the funniest technical book ever written</strong>, this
+is a vicious but well-reasoned attack on the OSI "seven layer model" and all
+that went with it. Several chapters of it are also available as RFCs 871 to
+875.</p>
+<hr>
+<a name="matrix">John S. Quarterman</a> <cite>The Matrix: Computer Networks
+and Conferencing Systems Worldwide</cite><br>
+Digital Press 1990  ISBN 155558-033-5<br>
+Prentice-Hall ISBN 0-13-565607-9
+
+<p>The best general treatment of computer-mediated communication we have
+seen. It naturally has much to say about the Internet, but also covers UUCP,
+Fidonet and so on.</p>
+<hr>
+<a name="ranch">David Ranch</a> <cite>Securing Linux Step by Step</cite><br>
+SANS Institute, 1999
+
+<p><a href="http://www.sans.org/">SANS</a> is a respected organisation, this
+guide is part of a well-known series, and Ranch has previously written the
+useful <a
+href=" http://www.ecst.csuchico.edu/~dranch/LINUX/index-linux.html#trinityos">Trinity
+OS</a> guide to securing Linux, so my guess would be this is a pretty good
+book. I haven't read it yet, so I'm not certain. It can be ordered online
+from <a href="http://www.sans.org/">SANS</a>.</p>
+
+<p>Note (Mar 1, 2002): a new edition with different editors in the works.
+Expect it this year.</p>
+<hr>
+<a name="schneier">Bruce Schneier</a> <cite>Applied Cryptography, Second
+Edition</cite><br>
+John Wiley &amp; Sons, 1996<br>
+ISBN 0-471-12845-7 hardcover<br>
+ISBN 0-471-11709-9 paperback
+
+<p>A standard reference on computer cryptography. For more recent essays, see
+the <a href="http://www.counterpane.com/">author's company's web site</a>.</p>
+<hr>
+<a name="secrets">Bruce Schneier</a><cite> Secrets and Lies</cite><br>
+Wiley 2000, ISBN 0-471-25311-1
+
+<p>An interesting discussion of security and privacy issues, written with
+more of an "executive overview" approach rather than a narrow focus on the
+technical issues. <strong>Highly recommended</strong>.</p>
+
+<p>This is worth reading even if you already understand security issues, or
+think you do. To go deeper, follow it with Anderson's <a
+href="#anderson">Security Engineering</a>.</p>
+<hr>
+<a name="VPNbook">Scott, Wolfe and Irwin <cite>Virtual Private
+Networks</cite></a><br>
+2nd edition, O'Reilly 1999 ISBN: 1-56592-529-7
+
+<p>This is the only O'Reilly book, out of a dozen I own, that I'm
+disappointed with. It deals mainly with building VPNs with various
+proprietary tools -- <a href="glossary.html#PPTP">PPTP</a>, <a
+href="glossary.html#SSH">SSH</a>, Cisco PIX, ... -- and touches only lightly
+on IPsec-based approaches.</p>
+
+<p>That said, it appears to deal competently with what it does cover and it
+has readable explanations of many basic VPN and security concepts. It may be
+exactly what some readers require, even if I find the emphasis
+unfortunate.</p>
+<hr>
+<a name="LASG">Kurt Seifried <cite>Linux Administrator's Security
+Guide</cite></a>
+
+<p>Available online from <a
+href="http://www.securityportal.com/lasg/">Security Portal</a>. It has fairly
+extensive coverage of IPsec.</p>
+<hr>
+<a name="Smith">Richard E Smith <cite>Internet Cryptography</cite><br>
+</a>ISBN 0-201-92480-3, Addison Wesley, 1997
+
+<p>See the book's <a
+href="http://www.visi.com/crypto/inet-crypto/index.html">home page</a></p>
+<hr>
+<a name="neal">Neal Stephenson <cite>Cryptonomicon</cite></a><br>
+Hardcover ISBN -380-97346-4, Avon, 1999.
+
+<p>A novel in which cryptography and the net figure prominently.
+<strong>Highly recommended</strong>: I liked it enough I immediately went out
+and bought all the author's other books.</p>
+
+<p>There is also a paperback edition. Sequels are expected.</p>
+<hr>
+<a name="stevens">Stevens and Wright</a> <cite>TCP/IP Illustrated</cite><br>
+Addison-Wesley
+<ul>
+  <li>Vol. I: The Protocols 1994 ISBN:0-201-63346-9</li>
+  <li>Vol. II: The Implementation 1995 ISBN:0-201-63354-X</li>
+  <li>Vol. III: TCP for Transactions, HTTP, NNTP, and the UNIX Domain
+    Protocols 1996 ISBN: 0-201-63495-3</li>
+</ul>
+
+<p>If you need to deal with the details of the network protocols, read either
+this series or the <a href="#comer">Comer</a> series before you start reading
+the RFCs.</p>
+<hr>
+<a name="Rubini">Rubini</a> <cite>Linux Device Drivers</cite><br>
+O'Reilly &amp; Associates, Inc. 1998 ISBN 1-56592-292-1
+<hr>
+<a name="Zeigler">Robert Zeigler</a> <cite>Linux Firewalls</cite><br>
+Newriders Publishing, 2000 ISBN 0-7537-0900-9
+
+<p>A good book, with detailed coverage of ipchains(8) firewalls and of many
+related issues.</p>
+</body>
+</html>
diff --git a/doc/src/buildtools.html b/doc/src/buildtools.html
new file mode 100644
index 000000000..c8cfa1fc8
--- /dev/null
+++ b/doc/src/buildtools.html
@@ -0,0 +1,27 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
+<HTML>
+  <HEAD>
+    <TITLE>Tools used to build FreeSWAN releases (08-Mar-2002)</TITLE>
+    <!-- Created by: Michael Richardson, 08-Mar-2002 -->
+
+
+  </HEAD>
+  <BODY>
+    <H1>Tools used to build FreeSWAN releases</H1>
+
+<H2>man2html</H2>
+
+<P>
+If you are not running RedHat, you will need man2html. This is part of the
+"man" RPM on RedHat, whose sources can be found at <A HREF="ftp://ftp.win.tue.nl/pub/linux-local/utils/man/">ftp://ftp.win.tue.nl/pub/linux-local/utils/man/</A>.
+</P>
+
+<P>
+Note that the Debian package <A HREF="http://packages.debian.org/man2html">man2html</A>
+and the one listed on Freshmeat at
+<A HREF="http://freshmeat.net/projects/man2html/">man2html</A> will
+not work.
+</P>
+
+  </BODY>
+</HTML>
\ No newline at end of file
diff --git a/doc/src/compat.html b/doc/src/compat.html
new file mode 100644
index 000000000..a8e1455bf
--- /dev/null
+++ b/doc/src/compat.html
@@ -0,0 +1,795 @@
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>FreeS/WAN compatibility guide</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, FreeSWAN, compatibility">
+  <!--
+
+  Written by Sandy Harris for the Linux FreeS/WAN project
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: compat.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+
+<body>
+<h1><a name="compat">Linux FreeS/WAN Compatibility Guide</a></h1>
+
+<p>Much of this document is quoted directly from the Linux FreeS/WAN <a
+href="mail.html">mailing list</a>. Thanks very much to the community of
+testers, patchers and commenters there, especially the ones quoted below but
+also various contributors we haven't quoted.</p>
+
+<h2><a name="spec">Implemented parts of the IPsec Specification</a></h2>
+
+<p>In general, do not expect Linux FreeS/WAN to do everything yet. This is a
+work-in-progress and some parts of the IPsec specification are not yet
+implemented.</p>
+
+<h3><a name="in">In Linux FreeS/WAN</a></h3>
+
+<p>Things we do, as of version 1.96:</p>
+<ul>
+  <li>key management methods
+    <dl>
+      <dt>manually keyed</dt>
+        <dd>using keys stored in /etc/ipsec.conf</dd>
+      <dt>automatically keyed</dt>
+        <dd>Automatically negotiating session keys as required. All
+          connections are automatically re-keyed periodically. The <a
+          href="glossary.html#Pluto">Pluto</a> daemon implements this using
+          the <a href="glossary.html#IKE">IKE</a> protocol.</dd>
+    </dl>
+  </li>
+  <li>Methods of authenticating gateways for IKE
+    <dl>
+      <dt>shared secrets</dt>
+        <dd>stored in <a
+          href="manpage.d/ipsec.secrets.5.html">ipsec.secrets(5)</a></dd>
+      <dt><a href="glossary.html#RSA">RSA</a> signatures</dt>
+        <dd>For details, see <a
+          href="manpage.d/ipsec_pluto.8.html">pluto(8)</a>.</dd>
+      <dt>looking up RSA authentication keys from <a
+      href="glossary.html#DNS">DNS</a>.</dt>
+        <dd>Note that this technique cannot be fully secure until <a
+          href="glossary.html#SDNS">secure DNS</a> is widely deployed.</dd>
+    </dl>
+  </li>
+  <li>groups for <a href="glossary.html#DH">Diffie-Hellman</a> key negotiation
+    <dl>
+      <dt>group 2, modp 1024-bit</dt>
+      <dt>group 5, modp 1536-bit</dt>
+        <dd>We implement these two groups.
+          <p>In negotiating a keying connection (ISAKMP SA, Phase 1) we
+          propose both groups when we are the initiator, and accept either
+          when a peer proposes them. Once the keying connection is made, we
+          propose only the alternative agreed there for data connections
+          (IPsec SA's, Phase 2) negotiated over that keying connection.</p>
+        </dd>
+    </dl>
+  </li>
+  <li>encryption transforms
+    <dl>
+      <dt><a href="glossary.html#DES">DES</a></dt>
+        <dd>DES is in the source code since it is needed to implement 3DES,
+          but single DES is not made available to users because <a
+          href="politics.html#desnotsecure">DES is insecure</a>.</dd>
+      <dt><a href="glossary.html#3DES">Triple DES</a></dt>
+        <dd>implemented, and used as the default encryption in Linux
+          FreeS/WAN.</dd>
+    </dl>
+  </li>
+  <li>authentication transforms
+    <dl>
+      <dt><a href="glossary.html#HMAC">HMAC</a> using <a
+      href="glossary.html#MD5">MD5</a></dt>
+        <dd>implemented, may be used in IKE or by by AH or ESP
+        transforms.</dd>
+      <dt><a href="glossary.html#HMAC">HMAC</a> using <a
+      href="glossary.html#SHA">SHA</a></dt>
+        <dd>implemented, may be used in IKE or by AH or ESP transforms.</dd>
+    </dl>
+    <p>In negotiations, we propose both of these and accept either.</p>
+  </li>
+  <li>compression transforms
+    <dl>
+      <dt>IPComp</dt>
+        <dd>IPComp as described in RFC 2393 was added for FreeS/WAN 1.6. Note
+          that Pluto becomes confused if you ask it to do IPComp when the
+          kernel cannot.</dd>
+    </dl>
+  </li>
+</ul>
+
+<p>All combinations of implemented transforms are supported. Note that some
+form of packet-level <strong>authentication is required whenever encryption
+is used</strong>. Without it, the encryption will not be secure.</p>
+
+<h3><a name="dropped">Deliberately omitted</a></h3>
+We do not implement everything in the RFCs because some of those things are
+insecure. See our discussions of avoiding <a href="politics.html#weak">bogus
+security</a>.
+
+<p>Things we deliberately omit which are required in the RFCs are:</p>
+<ul>
+  <li>null encryption (to use ESP as an authentication-only service)</li>
+  <li>single DES</li>
+  <li>DH group 1, a 768-bit modp group</li>
+</ul>
+
+<p>Since these are the only encryption algorithms and DH group the RFCs
+require, it is possible in theory to have a standards-conforming
+implementation which will not interpoperate with FreeS/WAN. Such an
+implementation would be inherently insecure, so we do not consider this a
+problem.</p>
+
+<p>Anyway, most implementations sensibly include more secure options as well,
+so dropping null encryption, single DES and Group 1 does not greatly hinder
+interoperation in practice.</p>
+
+<p>We also do not implement some optional features allowed by the RFCs:</p>
+<ul>
+  <li>aggressive mode for negotiation of the keying channel or ISAKMP SA.
+    This mode is a little faster than main mode, but exposes more information
+    to an eavesdropper.</li>
+</ul>
+
+<p>In theory, this should cause no interoperation problems since all
+implementations are required to support the more secure main mode, whether or
+not they also allow aggressive mode.</p>
+
+<p>In practice, it does sometimes produce problems with implementations such
+as Windows 2000 where aggressive mode is the default. Typically, these are
+easily solved with a configuration change that overrides that default.</p>
+
+<h3><a name="not">Not (yet) in Linux FreeS/WAN</a></h3>
+
+<p>Things we don't yet do, as of version 1.96:</p>
+<ul>
+  <li>key management methods
+    <ul>
+      <li>authenticate key negotiations via local <a
+        href="glossary.html#PKI">PKI</a> server, but see links to user <a
+        href="web.html#patch">patches</a></li>
+      <li>authenticate key negotiations via <a
+        href="glossary.html#SDNS">secure DNS</a></li>
+      <li>unauthenticated key management, using <a
+        href="glossary.html#DH">Diffie-Hellman</a> key agreement protocol
+        without authentication. Arguably, this would be worth doing since it
+        is secure against all passive attacks. On the other hand, it is
+        vulnerable to an active <a
+        href="glossary.html#middle">man-in-the-middle attack</a>.</li>
+    </ul>
+  </li>
+  <li>encryption transforms
+    <p>Currently <a href="glossary.html#3DES">Triple DES</a> is the only
+    encryption method Pluto will negotiate.</p>
+    <p>No additional encryption transforms are implemented, though the RFCs
+    allow them and some other IPsec implementations support various of them.
+    We are not eager to add more. See this <a
+    href="faq.html#other.cipher">FAQ question</a>.</p>
+    <p><a href="glossary.html#AES">AES</a>, the successor to the DES
+    standard, is an excellent candidate for inclusion in FreeS/WAN, see links
+    to user <a href="web.html#patch">patches</a>.</p>
+  </li>
+  <li>authentication transforms
+    <p>No optional additional authentication transforms are currently
+    implemented. Likely <a href="glossary.html#SHA-256">SHA-256, SHA-384 and
+    SHA-512</a> will be added when AES is.</p>
+  </li>
+  <li>Policy checking on decrypted packets
+    <p>To fully comply with the RFCs, it is not enough just to accept only
+    packets which survive any firewall rules in place to limit what IPsec
+    packets get in, and then pass KLIPS authentication. That is what
+    FreeS/WAN currently does.</p>
+    <p>We should also apply additional tests, for example ensuring that all
+    packets emerging from a particular tunnel have source and destination
+    addresses that fall within the subnets defined for that tunnel, and that
+    packets with those addresses that did not emerge from the appropriate
+    tunnel are disallowed.</p>
+    <p>This will be done as part of a KLIPS rewrite. See these <a
+    href="intro.html#applied">links</a> and the <a href="mail.html">design
+    mailing list</a> for discussion.</p>
+  </li>
+</ul>
+
+<h2><a name="pfkey">Our PF-Key implementation</a></h2>
+
+<p>We use PF-key Version Two for communication between the KLIPS kernel code
+and the Pluto Daemon. PF-Key v2 is defined by <a
+href="http://www.normos.org/ietf/rfc/rfc2367.txt">RFC 2367</a>.</p>
+
+<p>The "PF" stands for Protocol Family. PF-Inet defines a kernel/userspace
+interface for the TCP/IP Internet protocols (TCP/IP), and other members of
+the PF series handle Netware, Appletalk, etc. PF-Key is just a PF for
+key-related matters.</p>
+
+<h3><a name="pfk.port">PF-Key portability</a></h3>
+
+<p>PF-Key came out of Berkeley Unix work and is used in the various BSD IPsec
+implementations, and in Solaris. This means there is some hope of porting our
+Pluto(8) to one of the BSD distributions, or of running their photurisd(8) on
+Linux if you prefer <a href="glossary.html#photuris">Photuris</a> key
+management over IKE.</p>
+
+<p>It is, however, more complex than that. The PK-Key RFC deliberately deals
+only with keying, not policy management. The three PF-Key implementations we
+have looked at -- ours, OpenBSD and KAME -- all have extensions to deal with
+security policy, and the extensions are different. There have been
+discussions aimed at sorting out the differences, perhaps for a version three
+PF-Key spec. All players are in favour of this, but everyone involved is busy
+and it is not clear whether or when these discussions might bear fruit.</p>
+
+<h2><a name="otherk">Kernels other than the latest 2.2.x and 2.4.y</a></h2>
+
+<p>We develop and test on Redhat Linux using the most recent kernel in the
+2.2 and 2.4 series. In general, we recommend you use the latest kernel in one
+of those series. Complications and caveats are discussed below.</p>
+
+<h3><a name="kernel.2.0">2.0.x kernels</a></h3>
+
+<p>Consider upgrading to the 2.2 kernel series. If you want to stay with the
+2.0 series, then we strongly recommend 2.0.39. Some useful security patches
+were added in 2.0.38.</p>
+
+<p>Various versions of the code have run at various times on most 2.0.xx
+kernels, but the current version is only lightly tested on 2.0.39, and not at
+all on older kernels.</p>
+
+<p>Some of our patches for older kernels are shipped in 2.0.37 and later, so
+they are no longer provided in FreeS/WAN. This means recent versions of
+FreeS/WAN will probably not compile on anything earlier than 2.0.37.</p>
+
+<h3><a name="kernel.production">2.2 and 2.4 kernels</a></h3>
+<dl>
+  <dt>FreeS/WAN 1.0</dt>
+    <dd>ran only on 2.0 kernels</dd>
+  <dt>FreeS/WAN 1.1 to 1.8</dt>
+    <dd>ran on 2.0 or 2.2 kernels<br>
+      ran on some development kernels, 2.3 or 2.4-test</dd>
+  <dt>FreeS/WAN 1.9 to 1.96</dt>
+    <dd>runs on 2.0, 2.2 or 2.4 kernels</dd>
+</dl>
+
+<p>In general, <strong>we suggest the latest 2.2 kernel or 2.4 for production
+use</strong>.</p>
+
+<p>Of course no release can be guaranteed to run on kernels more recent than
+it is, so quite often there will be no stable FreeS/WAN for the absolute
+latest kernel. See the <a href="faq.html#k.versions">FAQ</a> for
+discussion.</p>
+
+<h2><a name="otherdist">Intel Linux distributions other than Redhat</a></h2>
+
+<p>We develop and test on Redhat 6.1 for 2.2 kernels, and on Redhat 7.1 or
+7.2 for 2.4, so minor changes may be required for other distributions.</p>
+
+<h3><a name="rh7">Redhat 7.0</a></h3>
+
+<p>There are some problems with FreeS/WAN on Redhat 7.0. They are soluble,
+but we recommend you upgrade to a later Redhat instead..</p>
+
+<p>Redhat 7 ships with two compilers.</p>
+<ul>
+  <li>Their <var>gcc</var> is version 2.96. Various people, including the GNU
+    compiler developers and Linus, have said fairly emphatically that using
+    this was a mistake. 2.96 is a development version, not intended for
+    production use. In particular, it will not compile a Linux kernel.</li>
+  <li>Redhat therefore also ship a separate compiler, which they call
+    <var>kgcc</var>, for compiling kernels.</li>
+</ul>
+
+<p>Kernel Makefiles have <var>gcc</var> as a default, and must be adjusted to
+use <var>kgcc</var> before a kernel will compile on 7.0. This mailing list
+message gives details:</p>
+<pre>Subject: Re: AW: Installing IPsec on Redhat 7.0
+   Date: Thu, 1 Feb 2001 14:32:52 -0200 (BRST)
+  From: Mads Rasmussen &lt;mads@cit.com.br&gt;
+ 
+&gt; From www.redhat.com/support/docs/gotchas/7.0/gotchas-7-6.html#ss6.1
+
+cd to /usr/src/linux and open the Makefile in your favorite editor. You
+will need to look for a line similar to this:
+
+CC = $(CROSS_COMPILE)gcc -D__KERNEL__ -I$(HPATH)
+
+This line specifies which C compiler to use to build the kernel. It should
+be changed to:
+
+CC = $(CROSS_COMPILE)kgcc -D__KERNEL__ -I$(HPATH)
+
+for Red Hat Linux 7. The kgcc compiler is egcs 2.91.66. From here you can
+proceed with the typical compiling steps.</pre>
+
+<p>Check the <a href="mail.html">mailing list</a> archive for more recent
+news.</p>
+
+<h3><a name="suse">SuSE Linux</a></h3>
+
+<p>SuSE 6.3 and later versions, at least in Europe, ship with FreeS/WAN
+included.</p>
+
+<P>FreeS/WAN packages distributed for SuSE 7.0-7.2 were somehow
+miscompiled.  You can find fixed packages on 
+<A HREF="http://www.suse.de/~garloff/linux/FreeSWAN">
+Kurt Garloff's page</A>.</P>
+
+<p>Here are some notes for an earlier SuSE version.</p>
+
+<h4>SuSE Linux 5.3</h4>
+<pre>Date: Mon, 30 Nov 1998
+From: Peter Onion &lt;ponion@srd.bt.co.uk&gt;
+
+... I got Saturdays snapshot working between my two SUSE5.3 machines at home.
+
+The mods to the install process are quite simple.  From memory and looking at
+the files on the SUSE53 machine here at work....
+
+And extra link in each of the /etc/init.d/rc?.d directories called K35ipsec
+which SUSE use to shut a service down.
+
+A few mods in /etc/init.d/ipsec  to cope with the different places that SUSE
+put config info, and remove the inculsion of /etc/rc.d/init.d/functions and .
+/etc/sysconfig/network as they don't exists and 1st one isn't needed anyway.
+
+insert ". /etc/rc.config" to pick up the SUSE config info and use 
+
+  if test -n "$NETCONFIG" -a "$NETCONFIG" != "YAST_ASK" ; then
+
+to replace 
+
+  [ ${NETWORKING} = "no" ] &amp;&amp; exit 0
+
+Create /etc/sysconfig  as SUSE doesn't have one.
+
+I think that was all (but I prob forgot something)....</pre>
+
+<p>You may also need to fiddle initialisation scripts to ensure that
+<var>/var/run/pluto.pid</var> is removed when rebooting. If this file is
+present, Pluto does not come up correctly.</p>
+
+<h3><a name="slack">Slackware</a></h3>
+<pre>Subject: Re: linux-IPsec: Slackware distribution
+  Date:  Thu, 15 Apr 1999 12:07:01 -0700
+  From:  Evan Brewer &lt;dmessiah@silcon.com&gt;
+
+&gt; Very shortly, I will be needing to install IPsec on at least gateways that
+&gt; are running Slackware. . . .
+
+The only trick to getting it up is that on the slackware dist there is no
+init.d directory in /etc/rc.d .. so create one.  Then, what I do is take the
+IPsec startup script which normally gets put into the init.d directory, and
+put it in /etc/rc.d and name ir rc.ipsec .. then I symlink it to the file
+in init.d.  The only file in the dist you need to really edit is the
+utils/Makefile, setup4:
+
+Everything else should be just fine.</pre>
+
+<p>A year or so later:</p>
+<pre>Subject: Re: HTML Docs- Need some cleanup?
+   Date: Mon, 8 Jan 2001
+   From: Jody McIntyre &lt;jodym@oeone.com&gt;
+
+I have successfully installed FreeS/WAN on several Slackware 7.1 machines.
+FreeS/WAN installed its rc.ipsec file in /etc/rc.d.  I had to manually call
+this script from rc.inet2.  This seems to be an easier method than Evan
+Brewer's.</pre>
+
+<h3><a name="deb">Debian</a></h3>
+
+<p>A recent (Nov 2001) mailing list points to a <a
+href="http://www.thing.dyndns.org/debian/vpn.htm">web page</a> on setting up
+several types of tunnel, including IPsec, on Debian.</p>
+
+<p>Some older information:</p>
+<pre>Subject: FreeS/WAN 1.0 on Debian 2.1
+   Date: Tue, 20 Apr 1999
+  From:  Tim Miller &lt;cerebus+counterpane@haybaler.sackheads.org&gt;
+
+        Compiled and installed without error on a Debian 2.1 system
+with kernel-source-2.0.36 after pointing RCDIR in utils/Makefile to
+/etc/init.d.
+
+        /var/lock/subsys/ doesn't exist on Debian boxen, needs to be
+created; not a fatal error.
+
+        Finally, IPsec scripts appear to be dependant on GNU awk
+(gawk); the default Debian awk (mawk-1.3.3-2) had fatal difficulties.
+With gawk installed and /etc/alternatives/awk linked to /usr/bin/gawk
+operation appears flawless.</pre>
+
+<p>The scripts in question have been modified since this was posted. Awk
+versions should no longer be a problem.</p>
+
+<h3><a name="caldera">Caldera</a></h3>
+<pre>Subject: Re: HTML Docs- Need some cleanup?
+   Date: Mon, 08 Jan 2001
+   From: Andy Bradford &lt;andyb@calderasystems.com&gt;
+
+On Sun, 07 Jan 2001 22:59:05 EST, Sandy Harris wrote:
+
+&gt;     Intel Linux distributions other than Redhat 5.x and 6.x 
+&gt;         Redhat 7.0 
+&gt;         SuSE Linux 
+&gt;             SuSE Linux 5.3 
+&gt;         Slackware 
+&gt;         Debian 
+
+Can you please include Caldera in this list?  I have tested it since 
+FreeS/Wan 1.1 and it works great with our systems---provided one 
+follows the FreeS/Wan documentation. :-)
+
+Thank you,
+Andy</pre>
+
+<h2><a name="CPUs">CPUs other than Intel</a></h2>
+
+<p>FreeS/WAN has been run sucessfully on a number of different CPU
+architectures. If you have tried it on one not listed here, please post to
+the <a href="mail.html">mailing list</a>.</p>
+
+<h3><a name=" strongarm">Corel Netwinder (StrongARM CPU)</a></h3>
+<pre>Subject: linux-ipsec: Netwinder diffs
+Date: Wed, 06 Jan 1999
+From: rhatfield@plaintree.com
+
+I had a mistake in my IPsec-auto, so I got things working this morning.
+
+Following are the diffs for my changes.  Probably not the best and cleanest way 
+of doing it, but it works. . . . </pre>
+
+<p>These diffs are in the 0.92 and later distributions, so these should work
+out-of-the-box on Netwinder.</p>
+
+<h3><a name="yellowdog">Yellow Dog Linux on Power PC</a></h3>
+<pre>Subject:  Compiling FreeS/WAN 1.1 on YellowDog Linux (PPC)
+   Date:  11 Dec 1999
+   From:  Darron Froese &lt;darron@fudgehead.com&gt;
+
+I'm summarizing here for the record - because it's taken me many hours to do
+this (multiple times) and because I want to see IPsec on more linuxes than
+just x86.
+
+Also, I can't remember if I actually did summarize it before... ;-) I'm
+working too many late hours.
+
+That said - here goes.
+
+1. Get your linux kernel and unpack into /usr/src/linux/ - I used 2.2.13.
+&lt;http://www.kernel.org/pub/linux/kernel/v2.2/linux-2.2.13.tar.bz2&gt;
+
+2. Get FreeS/WAN and unpack into /usr/src/freeswan-1.1
+&lt;ftp://ftp.xs4all.nl/pub/crypto/freeswan/freeswan-1.1.tar.gz&gt;
+
+3. Get the gmp src rpm from here:
+&lt;ftp://ftp.yellowdoglinux.com//pub/yellowdog/champion-1.1/SRPMS/SRPMS/gmp-2.0.2-9a.src.rpm&gt;
+
+4. Su to root and do this: rpm --rebuild gmp-2.0.2-9a.src.rpm
+
+You will see a lot of text fly by and when you start to see the rpm
+recompiling like this:
+
+Executing: %build
++ umask 022
++ cd /usr/src/redhat/BUILD
++ cd gmp-2.0.2
++ libtoolize --copy --force
+Remember to add `AM_PROG_LIBTOOL' to `configure.in'.
+You should add the contents of `/usr/share/aclocal/libtool.m4' to
+`aclocal.m4'.
++ CFLAGS=-O2 -fsigned-char
++ ./configure --prefix=/usr
+
+Hit Control-C to stop the rebuild. NOTE: We're doing this because for some
+reason the gmp source provided with FreeS/WAN 1.1 won't build properly on
+ydl.
+
+cd /usr/src/redhat/BUILD/
+cp -ar gmp-2.0.2 /usr/src/freeswan-1.1/
+cd /usr/src/freeswan-1.1/
+rm -rf gmp
+mv gmp-2.0.2 gmp
+
+5. Open the freeswan Makefile and change the line that says:
+KERNEL=$(b)zimage (or something like that) to
+KERNEL=vmlinux
+
+6. cd ../linux/
+
+7. make menuconfig
+Select an option or two and then exit - saving your changes.
+
+8. cd ../freeswan-1.1/ ; make menugo
+
+That will start the whole process going - once that's finished compiling,
+you have to install your new kernel and reboot.
+
+That should build FreeS/WAN on ydl (I tried it on 1.1).</pre>
+And a later message on the same topic:
+<pre>Subject: Re: FreeS/WAN, PGPnet and E-mail
+   Date: Sat, 22 Jan 2000
+   From: Darron Froese &lt;darron@fudgehead.com&gt;
+
+on 1/22/00 6:47 PM, Philip Trauring at philip@trauring.com wrote:
+
+&gt; I have a PowerMac G3 ...
+
+The PowerMac G3 can run YDL 1.1 just fine. It should also be able to run
+FreeS/WAN 1.2patch1 with a couple minor modifications:
+
+1. In the Makefile it specifies a bzimage for the kernel compile - you have
+to change that to vmlinux for the PPC.
+
+2. The gmp source that comes with FreeS/WAN (for whatever reason) fails to
+compile. I have gotten around this by getting the gmp src rpm from here:
+
+ftp://ftp.yellowdoglinux.com//pub/yellowdog/champion-1.1/SRPMS/SRPMS/gmp-2.0.2-9a.src.rpm
+
+If you rip the source out of there - and place it where the gmp source
+resides it will compile just fine.</pre>
+
+<p>FreeS/WAN no longer includes GMP source.</p>
+
+<h3><a name="mklinux">Mklinux</a></h3>
+
+<p>One user reports success on the Mach-based
+<strong>m</strong>icro<strong>k</strong>ernel Linux.</p>
+<pre>Subject: Smiles on sparc and ppc
+   Date: Fri, 10 Mar 2000
+   From: Jake Hill &lt;jah@alien.bt.co.uk&gt;
+
+You may or may not be interested to know that I have successfully built
+FreeS/WAN on a number of non intel alpha architectures; namely on ppc
+and sparc and also on osfmach3/ppc (MkLinux). I can report that it just
+works, mostly, with few changes.</pre>
+
+<h3><a name="alpha">Alpha 64-bit processors</a></h3>
+<pre>Subject: IT WORKS (again) between intel &amp; alpha :-)))))
+   Date: Fri, 29 Jan 1999
+   From: Peter Onion &lt;ponion@srd.bt.co.uk&gt;
+
+Well I'm happy to report that I've got an IPsec connection between by intel &amp; alpha machines again :-))
+
+If you look back on this list to 7th of December I wrote...
+
+-On 07-Dec-98 Peter Onion wrote:
+-&gt; 
+-&gt; I've about had enuf of wandering around inside the kernel trying to find out
+-&gt; just what is corrupting outgoing packets...
+-
+-Its 7:30 in the evening .....
+-
+-I FIXED IT  :-))))))))))))))))))))))))))))))))
+-
+-It was my own fault :-((((((((((((((((((
+-
+-If you ask me very nicly I'll tell you where I was a little too over keen to
+-change unsigned long int __u32 :-)  OPSE ...
+-
+-So tomorrow it will full steam ahead to produce a set of diffs/patches against
+-0.91 
+-
+-Peter Onion.</pre>
+
+<p>In general (there have been some glitches), FreeS/WAN has been running on
+Alphas since then.</p>
+
+<h3><a name="SPARC">Sun SPARC processors</a></h3>
+
+<p>Several users have reported success with FreeS/WAN on SPARC Linux. Here is
+one mailing list message:</p>
+<pre>Subject: Smiles on sparc and ppc
+   Date: Fri, 10 Mar 2000
+   From: Jake Hill &lt;jah@alien.bt.co.uk&gt;
+
+You may or may not be interested to know that I have successfully built
+FreeS/WAN on a number of non intel alpha architectures; namely on ppc
+and sparc and also on osfmach3/ppc (MkLinux). I can report that it just
+works, mostly, with few changes.
+
+I have a question, before I make up some patches. I need to hack
+gmp/mpn/powerpc32/*.s to build them. Is this ok? The changes are
+trivial, but could I also use a different version of gmp? Is it vanilla
+here?
+
+I guess my only real headache is from ipchains, which appears to stop
+running when IPsec has been started for a while. This is with 2.2.14 on
+sparc.</pre>
+
+<p>This message, from a different mailing list, may be relevant for anyone
+working with FreeS/WAN on Suns:</p>
+<pre>Subject: UltraSPARC DES assembler
+   Date: Thu, 13 Apr 2000
+   From: svolaf@inet.uni2.dk (Svend Olaf Mikkelsen)
+     To: coderpunks@toad.com
+
+An UltraSPARC assembler version of the LibDES/SSLeay/OpenSSL des_enc.c
+file is available at http://inet.uni2.dk/~svolaf/des.htm.
+
+This brings DES on UltraSPARC from slower than Pentium at the same
+clock speed to significantly faster.</pre>
+
+<h3><a name="mips">MIPS processors</a></h3>
+
+<p>We know FreeS/WAN runs on at least some MIPS processors because <a
+href="http://www.lasat.com">Lasat</a> manufacture an IPsec box based on an
+embedded MIPS running Linux with FreeS/WAN. We have no details.</p>
+
+<h3><a name="crusoe">Transmeta Crusoe</a></h3>
+
+<p>The Merilus <a
+href="http://www.merilus.com/products/fc/index.shtml">Firecard</a>, a Linux
+firewall on a PCI card, is based on a Crusoe processor and supports
+FreeS/WAN.</p>
+
+<h3><a name="coldfire">Motorola Coldfire</a></h3>
+<pre>Subject: Re: Crypto hardware support
+   Date: Mon, 03 Jul 2000
+   From: Dan DeVault &lt;devault@tampabay.rr.com&gt;
+
+.... I have been running
+uClinux with FreeS/WAN 1.4 on a system built by Moreton Bay  (
+http://www.moretonbay.com )  and it was using a Coldfire processor
+and was able to do the Triple DES encryption at just about
+1 mbit / sec rate.......  they put a Hi/Fn 7901 hardware encryption
+chip on their board and now their system does over 25 mbit of 3DES
+encryption........ pretty significant increase if you ask me.</pre>
+
+<h2><a name="multiprocessor">Multiprocessor machines</a></h2>
+
+<p>FreeS/WAN is designed to work on SMP (symmetric multi-processing) Linux
+machines and is regularly tested on dual processor x86 machines.</p>
+
+<p>We do not know of any testing on multi-processor machines with other CPU
+architectures or with more than two CPUs. Anyone who does test this, please
+report results to the <a href="mail.html">mailing list</a>.</p>
+
+<p>The current design does not make particularly efficient use of
+multiprocessor machines; some of the kernel work is single-threaded.</p>
+
+<h2><a name="hardware">Support for crypto hardware</a></h2>
+
+<p>Supporting hardware cryptography accelerators has not been a high priority
+for the development team because it raises a number of fairly complex
+issues:</p>
+<ul>
+  <li>Can you trust the hardware? If it is not Open Source, how do you audit
+    its security? Even if it is, how do you check that the design has no
+    concealed traps?</li>
+  <li>If an interface is added for such hardware, can that interface be
+    subverted or misused?</li>
+  <li>Is hardware acceleration actually a performance win? It clearly is in
+    many cases, but on a fast machine it might be better to use the CPU for
+    the encryption than to pay the overheads of moving data to and from a
+    crypto board.</li>
+  <li>the current KLIPS code does not provide a clean interface for hardware
+    accelerators</li>
+</ul>
+
+<p>That said, we have a <a href="#coldfire">report</a> of FreeS/WAN working
+with one crypto accelerator and some work is going on to modify KLIPS to
+create a clean generic interface to such products. See this <a
+href="http://www.jukie.net/~bart/linux-ipsec/">web page</a> for some of the
+design discussion.</p>
+
+<p>More recently, a patch to support some hardware accelerators has been
+posted:</p>
+<pre>Subject: [Design] [PATCH] H/W acceleration patch
+   Date: Tue, 18 Sep 2001
+   From: "Martin Gadbois" &lt;martin.gadbois@colubris.com&gt;
+ 
+Finally!!
+Here's a web site with H/W acceleration patch for FreeS/WAN 1.91, including
+S/W and Hifn 7901 crypto support.
+
+http://sources.colubris.com/
+
+Martin Gadbois</pre>
+
+<p>Hardware accelerators could take performance well beyond what FreeS/WAN
+can do in software (discussed <a href="performance.html">here</a>). Here is
+some discussion off the IETF IPsec list, October 2001:</p>
+<pre> ... Currently shipping chips deliver, 600 mbps throughput on a single
+ stream of 3DES IPsec traffic.  There are also chips that use multiple
+ cores to do 2.4 gbps.  We (Cavium) and others have announced even faster
+ chips. ... Mid 2002 versions will handle at line rate (OC48 and OC192)
+ IPsec and SSL/TLS traffic not only 3DES CBC but also AES and arc4.</pre>
+
+<p>The patches to date support chips that have been in production for some
+time, not the state-of-the-art latest-and-greatest devices described in that
+post. However, they may still outperform software and they almost certainly
+reduce CPU overhead.</p>
+
+<h2><a name="ipv6">IP version 6 (IPng)</a></h2>
+
+<p>The Internet currently runs on version four of the IP protocols. IPv4 is
+what is in the standard Linux IP stack, and what FreeS/WAN was built for. In
+IPv4, IPsec is an optional feature.</p>
+
+<p>The next version of the IP protocol suite is version six, usually
+abbreviated either as "IPv6" or as "IPng" for "IP: the next generation". For
+IPv6, IPsec is a required feature. Any machine doing IPv6 is required to
+support IPsec, much as any machine doing (any version of) IP is required to
+support ICMP.</p>
+
+<p>There is a Linux implementation of IPv6 in Linux kernels 2.2 and above.
+For details, see the <a
+href="http://www.cs-ipv6.lancs.ac.uk/ipv6/systems/linux/faq/">FAQ</a>. It
+does not yet support IPsec. The <a
+href="http://www.linux-ipv6.org/">USAGI</a> project are also working on IPv6
+for Linux.</p>
+
+<p>FreeS/WAN was originally built for the current standard, IPv4, but we are
+interested in seeing it work with IPv6. Some progress has been made, and a
+patched version with IPv6 support is <a
+href="http://www.ipv6.iabg.de/downloadframe/index.html">available</a>. For
+more recent information, check the <a href="mail.html">mailing list</a>.</p>
+
+<h3><a name="v6.back">IPv6 background</a></h3>
+
+<p>IPv6 has been specified by an IETF <a
+href="http://www.ietf.org/html.charters/ipngwg-charter.html">working
+group</a>. The group's page lists over 30 RFCs to date, and many Internet
+Drafts as well. The overview is <a
+href="http://www.ietf.org/rfc/rfc2460.txt">RFC 2460</a>. Major features
+include:</p>
+<ul>
+  <li>expansion of the address space from 32 to 128 bits,</li>
+  <li>changes to improve support for
+    <ul>
+      <li>mobile IP</li>
+      <li>automatic network configuration</li>
+      <li>quality of service routing</li>
+      <li>...</li>
+    </ul>
+  </li>
+  <li>improved security via IPsec</li>
+</ul>
+
+<p>A number of projects are working on IPv6 implementation. A prominent Open
+Source effort is <a href="http://www.kame.net/">KAME</a>, a collaboration
+among several large Japanese companies to implement IPv6 for Berkeley Unix.
+Other major players are also working on IPv6. For example, see pages at:</p>
+<ul>
+  <li><a
+  href="http://playground.sun.com/pub/ipng/html/ipng-main.html">Sun</a></li>
+  <li><a
+  href="http://www.cisco.com/warp/public/732/ipv6/index.html">Cisco</a></li>
+  <li><a
+    href="http://www.microsoft.com/windows2000/techinfo/howitworks/communications/networkbasics/IPv6.asp">Microsoft</a></li>
+</ul>
+
+<p>The <a href="http://www.6bone.net/">6bone</a> (IPv6 backbone) testbed
+network has been up for some time. There is an active <a
+href="http://www.ipv6.org/">IPv6 user group</a>.</p>
+
+<p>One of the design goals for IPv6 was that it must be possible to convert
+from v4 to v6 via a gradual transition process. Imagine the mess if there
+were a "flag day" after which the entire Internet used v6, and all software
+designed for v4 stopped working. Almost every computer on the planet would
+need major software changes! There would be huge costs to replace older
+equipment. Implementers would be worked to death before "the day", systems
+administrators and technical support would be completely swamped after it.
+The bugs in every implementation would all bite simultaneously. Large chunks
+of the net would almost certainly be down for substantial time periods.
+...</p>
+
+<p>Fortunately, the design avoids any "flag day". It is therefore a little
+tricky to tell how quickly IPv6 will take over. The transition has certainly
+begun. For examples, see announcements from <a
+href="http://www.mailbase.ac.uk/lists/internet2/2000-03/0016.html">NTT</a>
+and <a href="http://www.vnunet.com/News/1102383">Nokia</a>. However, it is
+not yet clear how quickly the process will gain momentum, or when it will be
+completed. Likely large parts of the Internet will remain with IPv4 for years
+to come.</p>
+</body>
+</html>
diff --git a/doc/src/config.html b/doc/src/config.html
new file mode 100644
index 000000000..b98e452db
--- /dev/null
+++ b/doc/src/config.html
@@ -0,0 +1,394 @@
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>FreeS/WAN configuration</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, FreeSWAN, installation, quickstart">
+  <!--
+
+  Written by Claudia Schmeing for the Linux FreeS/WAN project
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: config.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+<BODY>
+<H1><A NAME="config">How to configure FreeS/WAN</A></H1>
+
+<P>This page will teach you how to configure a simple network-to-network
+link or a Road Warrior connection between two Linux FreeS/WAN boxes.
+</P>
+
+<P>See also these related documents:</P>
+<UL>
+<LI>our <A HREF="quickstart.html#quickstart">quickstart</A> guide
+to <A HREF="glossary.html#carpediem">opportunistic encryption</A></LI>
+<LI>our guide to configuration with 
+<A HREF="policygroups.html#policygroups">policy groups</A></LI>
+<LI>our  
+<A HREF="adv_config.html#adv_config">advanced configuration</A>
+document</LI>
+</UL>
+<P>
+The network-to-network setup allows you to connect two office 
+networks into one Virtual Private Network, while the Road Warrior 
+connection secures a laptop's telecommute to work.
+Our examples also show the basic procedure on the Linux FreeS/WAN side where 
+another IPsec peer is in play.</P>
+
+<P>
+Shortcut to <A HREF="#config.netnet">net-to-net</A>.<BR>
+Shortcut to <A HREF="#config.rw">Road Warrior</A>.
+</P>
+
+<H2>Requirements</H2>
+
+<P>To configure the network-to-network connection you must have:</P>
+<UL>
+<LI>two Linux gateways with static IPs</LI>
+<LI>a network behind each gate. Networks must have non-overlapping IP ranges.</LI>
+<LI>Linux FreeS/WAN <A HREF="install.html#install">installed</A>
+  on both gateways</LI>
+<LI><A HREF="http://www.tcpdump.org"><VAR>tcpdump</VAR></A> on the local gate, 
+  to test the connection</LI>
+</UL>
+<P>For the Road Warrior you need:</P>
+<UL>
+<LI>one Linux box with a static IP</LI>
+<LI>a Linux laptop with a dynamic IP</LI>
+<LI>Linux FreeS/WAN installed on both</LI>
+<LI>for testing, <VAR>tcpdump</VAR> on your gateway or laptop</LI>
+</UL>
+
+<P>If both IPs are dynamic, your situation is a bit trickier. Your best bet
+is a variation on the <A HREF="#config.rw">Road Warrior</A>, as described
+in <A HREF="http://lists.freeswan.org/archives/users/2003-October/msg00282.html">this mailing list message</A>.
+
+<H2><A name="config.netnet"></A>Net-to-Net connection</H2>
+
+
+<H3><A name="netnet.info.ex">Gather information</A></H3>
+
+<P>For each gateway, compile the following information:</P>
+<UL>
+<LI>gateway IP</LI>
+<LI>IP range of the subnet you will be protecting. This doesn't have to 
+  be your whole physical subnet.</LI>
+<LI>a name by which that gateway can identify itself for IPsec
+negotiations. Its form is a Fully Qualified Domain Name preceded by
+an @ sign, ie. @xy.example.com.
+<BR>It does not need to be within a domain that you own. It can be a made-up
+name.</LI>
+</UL>
+
+
+<H4>Get your leftrsasigkey</H4>
+<P>On your local Linux FreeS/WAN gateway, print your IPsec public key:</P>
+<PRE>    ipsec showhostkey --left</PRE>
+<P>The output should look like this (with the key shortened for easy
+ reading):</P>
+<PRE>    # RSA 2048 bits   xy.example.com   Fri Apr 26 15:01:41 2002
+    leftrsasigkey=0sAQOnwiBPt...</PRE>
+
+<P>Don't have a key? Use
+<A HREF="manpage.d/ipsec_newhostkey.8.html"><VAR>ipsec newhostkey</VAR></A>
+to create one.
+
+<H4>...and your rightrsasigkey</H4>
+<P>Get a console on the remote side:</P>
+<PRE>    ssh2 ab.example.com</PRE>
+<P>In that window, type:</P>
+<PRE>    ipsec showhostkey --right</PRE>
+<P>You'll see something like:</P>
+<PRE>    # RSA 2192 bits   ab.example.com   Thu May 16 15:26:20 2002
+    rightrsasigkey=0sAQOqH55O...</PRE>
+
+<H3>Edit <VAR>/etc/ipsec.conf</VAR></H3>
+
+<P>Back on the local gate, copy our template to <VAR>/etc/ipsec.conf</VAR>. 
+(on Mandrake, <VAR>/etc/freeswan/ipsec.conf</VAR>).
+Substitute the information you've gathered for our example data.</P>
+<PRE>conn net-to-net
+    left=192.0.2.2                 # Local vitals
+    leftsubnet=192.0.2.128/29      # 
+    leftid=@xy.example.com         #   
+    leftrsasigkey=0s1LgR7/oUM...   #
+    leftnexthop=%defaultroute      # correct in many situations 
+    right=192.0.2.9                # Remote vitals
+    rightsubnet=10.0.0.0/24        #
+    rightid=@ab.example.com        # 
+    rightrsasigkey=0sAQOqH55O...   #
+    rightnexthop=%defaultroute     # correct in many situations
+    auto=add                       # authorizes but doesn't start this 
+                                   # connection at startup</PRE>
+
+<P>
+"Left" and "right" should represent the machines that have FreeS/WAN installed
+on them, and "leftsubnet" and "rightsubnet" machines that are being protected.
+/32 is assumed for left/right and left/rightsubnet parameters.
+</P>
+
+<P>Copy <VAR>conn net-to-net</VAR> to the remote-side /etc/ipsec.conf.
+If you've made no other modifications to either <VAR>ipsec.conf</VAR>, 
+simply:</P>
+<PRE>    scp2 ipsec.conf root@ab.example.com:/etc/ipsec.conf</PRE>
+
+<H3>Start your connection</H3>
+
+<P>Locally, type:</P>
+<PRE>    ipsec auto --up net-to-net</PRE>
+
+<P>You should see:</P>
+<PRE>    104 "net-net" #223: STATE_MAIN_I1: initiate
+    106 "net-net" #223: STATE_MAIN_I2: sent MI2, expecting MR2
+    108 "net-net" #223: STATE_MAIN_I3: sent MI3, expecting MR3
+    004 "net-net" #223: STATE_MAIN_I4: ISAKMP SA established
+    112 "net-net" #224: STATE_QUICK_I1: initiate
+    004 "net-net" #224: STATE_QUICK_I2: sent QI2, IPsec SA established</PRE>
+
+<P>The important thing is <VAR>IPsec SA established</VAR>. If you're 
+unsuccessful, see our 
+<A HREF="trouble.html#trouble">troubleshooting tips</A>.</P>
+
+
+<H3>Do not MASQ or NAT packets to be tunneled</H3>
+
+<P>If you are using <A HREF="glossary.html#masq">IP masquerade</A> or 
+<A HREF="glossary.html#NAT.gloss">Network Address Translation (NAT)</A> 
+on either gateway, 
+you must now exempt the packets you wish to tunnel from this treatment.
+For example, if you have a rule like:</P>
+
+<PRE>iptables -t nat -A POSTROUTING -o eth0 -s 10.0.0.0/24 -j MASQUERADE
+</PRE>
+
+<P>change it to something like:</P>
+<PRE>iptables -t nat -A POSTROUTING -o eth0 -s 10.0.0.0/24 -d \! 192.0.2.128/29 -j MASQUERADE</PRE>
+
+<P>This may be necessary on both gateways.</P>
+
+
+<H3>Test your connection</H3>
+
+<P>Sit at one of your local subnet nodes (not the gateway), and ping a subnet 
+node on the other (again, not the gateway).</P>
+
+<PRE>    ping fileserver.toledo.example.com</PRE>
+
+<P>While still pinging, go to the local gateway and snoop your outgoing 
+interface, for example:</P>
+<PRE>    tcpdump -i ppp0</PRE>
+<P>You want to see ESP (Encapsulating Security Payload) packets moving
+<B>back and forth</B> between the two gateways at the same frequency as 
+your pings:</P>
+<PRE>    19:16:32.046220 192.0.2.2 > 192.0.2.9: ESP(spi=0x3be6c4dc,seq=0x3)
+    19:16:32.085630 192.0.2.9 > 192.0.2.2: ESP(spi=0x5fdd1cf8,seq=0x6)</PRE>
+
+<P>If you see this, congratulations are in order! You have a tunnel which 
+will protect any IP data from one subnet
+to the other, as it passes between the two gates.
+If not, go and <A HREF="trouble.html#trouble">troubleshoot</A>.</P>
+
+<P>Note: your new tunnel protects only net-net traffic, not 
+gateway-gateway, or gateway-subnet. If you need this (for example, if
+machines on one net need to securely contact a fileserver on the 
+IPsec gateway), you'll need to create
+<A HREF="adv_config.html#adv_config">extra connections</A>.</P>
+
+
+<H3>Finishing touches</H3>
+
+<P>Now that your connection works, name it something sensible, like:</P>
+<PRE>conn winstonnet-toledonet</PRE>
+<P>To have the tunnel come up on-boot, replace</P>
+<PRE>    auto=add</PRE>
+<P>with:</P>
+<PRE>    auto=start</PRE>
+<P>Copy these changes to the other side, for example:</P>
+<PRE>    scp2 ipsec.conf root@ab.example.com:/etc/ipsec.conf</PRE>
+<P>Enjoy!</P>
+
+
+
+<H2><A name="config.rw"></A>Road Warrior Configuration</H2>
+
+<H3><A name="rw.info.ex">Gather information</A></H3>
+
+<P>You'll need to know:</P>
+<UL>
+<LI>the gateway's static IP</LI>
+<LI>the IP range of the subnet behind that gateway</LI>
+<LI>a name by which each side can identify itself for IPsec
+negotiations. Its form is a Fully Qualified Domain Name preceded by
+an @ sign, ie. @road.example.com.
+<BR>It does not need to be within a domain that you own. It can be a made-up
+name.</LI>
+</UL>
+
+<H4>Get your leftrsasigkey...</H4>
+<P>On your laptop, print your IPsec public key:</P>
+<PRE>    ipsec showhostkey --left</PRE>
+<P>The output should look like this (with the key shortened for easy
+ reading):</P>
+<PRE>    # RSA 2192 bits   road.example.com   Sun Jun  9 02:45:02 2002
+    leftrsasigkey=0sAQPIPN9uI...</PRE>
+
+<P>Don't have a key? See 
+<A HREF="old_config.html#genrsakey">these instructions</A>.
+
+
+<H4>...and your rightrsasigkey</H4>
+<P>Get a console on the gateway:</P>
+<PRE>    ssh2 xy.example.com</PRE>
+<P>View the gateway's public key with:</P>
+<PRE>    ipsec showhostkey --right</PRE>
+<P>This will yield something like</P>
+<PRE>    # RSA 2048 bits   xy.example.com   Fri Apr 26 15:01:41 2002
+    rightrsasigkey=0sAQOnwiBPt...</PRE>
+ 
+
+<H3>Customize <VAR>/etc/ipsec.conf</VAR></H3>
+
+<P>On your laptop, copy this template to <VAR>/etc/ipsec.conf</VAR>. 
+(on Mandrake, <VAR>/etc/freeswan/ipsec.conf</VAR>).
+Substitute the information you've gathered for our example data.</P>
+<PRE>conn road
+    left=%defaultroute             # Picks up our dynamic IP 
+    leftnexthop=%defaultroute      # 
+    leftid=@road.example.com       # Local information
+    leftrsasigkey=0sAQPIPN9uI...   #
+    right=192.0.2.10               # Remote information
+    rightsubnet=10.0.0.0/24        #
+    rightid=@xy.example.com        # 
+    rightrsasigkey=0sAQOnwiBPt...  #
+    auto=add                       # authorizes but doesn't start this
+                                   # connection at startup</PRE>
+
+<P>The template for the gateway is different. Notice how it
+reverses <VAR>left</VAR> and <VAR>right</VAR>, in keeping with our
+convention that <STRONG>L</STRONG>eft is <STRONG>L</STRONG>ocal, 
+<STRONG>R</STRONG>ight <STRONG>R</STRONG>emote. Be sure to switch your
+rsasigkeys in keeping with this.</P>
+
+<PRE>    ssh2 xy.example.com
+    vi /etc/ipsec.conf</PRE>
+
+<P>and add:</P>
+
+<PRE>conn road
+    left=192.0.2.2                 # Gateway's information
+    leftid=@xy.example.com         #
+    leftsubnet=192.0.2.128/29      #
+    leftrsasigkey=0sAQOnwiBPt...   #
+    rightnexthop=%defaultroute     # correct in many situations
+    right=%any                     # Wildcard: we don't know the laptop's IP
+    rightid=@road.example.com      #
+    rightrsasigkey=0sAQPIPN9uI...  #
+    auto=add                       # authorizes but doesn't start this
+                                   # connection at startup</PRE>
+
+
+
+<H3>Start your connection</H3>
+
+<P>You must start the connection from the Road Warrior side. On your laptop,
+type:</P>
+<PRE>    ipsec auto --start net-to-net</PRE>
+
+<P>You should see:</P>
+<PRE>104 "net-net" #223: STATE_MAIN_I1: initiate
+106 "road" #301: STATE_MAIN_I2: sent MI2, expecting MR2
+108 "road" #301: STATE_MAIN_I3: sent MI3, expecting MR3
+004 "road" #301: STATE_MAIN_I4: ISAKMP SA established
+112 "road" #302: STATE_QUICK_I1: initiate
+004 "road" #302: STATE_QUICK_I2: sent QI2, IPsec SA established</PRE>
+
+<P>Look for <VAR>IPsec SA established</VAR>. If you're 
+unsuccessful, see our 
+<A HREF="trouble.html#trouble">troubleshooting tips</A>.</P>
+
+
+
+<H3>Do not MASQ or NAT packets to be tunneled</H3>
+
+<P>If you are using <A HREF="glossary.html#masq">IP masquerade</A> or
+<A HREF="glossary.html#NAT.gloss">Network Address Translation (NAT)</A>
+on either gateway,
+you must now exempt the packets you wish to tunnel from this treatment.
+For example, if you have a rule like:</P>
+
+<PRE>iptables -t nat -A POSTROUTING -o eth0 -s 10.0.0.0/24 -j MASQUERADE
+</PRE>
+
+<P>change it to something like:</P>
+<PRE>iptables -t nat -A POSTROUTING -o eth0 -s 10.0.0.0/24 -d \! 192.0.2.128/29 -j MASQUERADE</PRE>
+
+
+<H3>Test your connection</H3>
+
+<P>From your laptop, ping a subnet node behind the remote gateway. Do not
+choose the gateway itself for this test.</P>
+
+<PRE>    ping ns.winston.example.com</PRE>
+
+<P>Snoop the packets exiting the laptop, with a command like:</P>
+<PRE>    tcpdump -i wlan0</PRE>
+<P>You have success if you see (Encapsulating Security Payload) packets 
+travelling <B>in both directions</B>:</P>
+
+<PRE>    19:16:32.046220 192.0.2.2 > 192.0.2.9: ESP(spi=0x3be6c4dc,seq=0x3)
+    19:16:32.085630 192.0.2.9 > 192.0.2.2: ESP(spi=0x5fdd1cf8,seq=0x6)</PRE>
+
+
+<P>If you do, great! Traffic between your Road Warrior and the net
+behind your gateway is protected.
+If not, see our 
+<A HREF="trouble.html#trouble">troubleshooting hints</A>.</P>
+
+<P>Your new tunnel protects only traffic addressed to the net, not to 
+the IPsec gateway itself. If you need the latter, you'll want to make an 
+<A HREF="adv_config.html#adv_config">extra tunnel.</A>.</P>
+
+<H3>Finishing touches</H3>
+
+<P>On both ends, name your connection wisely, like:</P>
+<PRE>conn mike-to-office</PRE>
+<P><B>On the laptop only,</B> replace</P>
+<PRE>    auto=add</PRE>
+<P>with:</P>
+<PRE>    auto=start</PRE>
+<P>so that you'll be connected on-boot.</P>
+<P>Happy telecommuting!</P>
+
+<H3>Multiple Road Warriors</H3>
+
+<P>If you're using RSA keys, as we did in this example, you can add
+as many Road Warriors as you like.  The left/rightid
+parameter lets Linux FreeS/WAN distinguish between multiple Road Warrior 
+peers, each with its own public key.</P>
+
+<P>The situation is different for shared secrets (PSK). During a 
+PSK negotiation, ID information is not available at the time Pluto 
+is trying to determine which secret to use, so, effectively, you can 
+only define one Roadwarrior connection. All your PSK road warriors
+must therefore share one secret.</P>
+
+
+<H2>What next?</H2>
+
+<P>Using the principles illustrated here, you can try variations such as:
+<UL>
+<LI>a telecommuter with a static IP</LI>
+<LI>a road warrior with a subnet behind it</LI>
+</UL>
+<P>Or, look at some of our <A HREF="adv_config.html#adv_config">more complex configuration examples.</A>.</P>
+</BODY>
+</HTML>
diff --git a/doc/src/crosscompile.html b/doc/src/crosscompile.html
new file mode 100644
index 000000000..c488957c8
--- /dev/null
+++ b/doc/src/crosscompile.html
@@ -0,0 +1,105 @@
+<HTML>

+<HEAD>

+	<TITLE>Cross Compiling FreeS/WAN</TITLE>

+      <meta name="keywords" content="Linux, IPSEC, VPN, Security, FreeSWAN, cross, compile">

+<!--

+     Written by Ken Bantoft <ken@freeswan.ca> for the Linux FreeS/WAN project

+     Freely distributable under the GNU General Public License

+

+     More information at www.freeswan.org

+     Feedback to users@lists.freeswan.org

+

+CVS information:

+RCS ID:          $Id: crosscompile.html,v 1.1 2004/03/15 20:35:24 as Exp $

+Last changed:    $Date: 2004/03/15 20:35:24 $

+Revision number: $Revision: 1.1 $

+

+CVS revision numbers do not correspond to FreeS/WAN release numbers.

+-->

+ 

+</HEAD>

+<BODY>

+

+<H1><A NAME="guide"></A>Linux FreeS/WAN Cross Compiling Guide</H1>

+

+<H2><A NAME="overview"></A>Overview</H2>

+

+<P>

+This document provides general instructions on how to cross compile 

+FreeS/WAN, 

+that is - compile it for another architecture (eg: StrongARM)</P>

+<OL>

+	<LI><A HREF="#setup">Setting up your environment</A>.</LI>

+	<LI><A HREF="#building">Building</A>.</LI>

+	<LI><A HREF="#common">Common Problems</A>.</LI>

+</OL>

+<H2><A NAME="setup"></A>Setting up your Environment</H2>

+<H3>Enviroment Variables</H3>

+<P>There are a number of environment variables you can set to help facilitate

+cross compiling FreeS/WAN.  All examples will are using the bash shell. 

+</P>

+<P>The following is an example of the how to set the environment variables if

+you were cross compiling using the Embedix ARM toolchain, to build for an embedded

+device like the Sharp Zaurus.  Set these while you are in the FreeS/WAN directory.

+It is often simpler to put the entire list into a script (eg: cross-setup.sh), and 

+then "source cross-setup.sh" or similar.

+<pre>

+export ARCH=arm

+export CC=/opt/Embedix/tools/bin/arm-linux-gcc

+export LD=/opt/Embedix/tools/bin/arm-linux-ld

+export RANLIB=/opt/Embedix/tools/bin/arm-linux-ranlib 

+export AR=/opt/Embedix/tools/bin/arm-linux-ar 

+export AS=/opt/Embedix/tools/bin/arm-linux-as 

+export STRIP=/opt/Embedix/tools/bin/arm-linux-strip 

+export KERNELSRC=/zaurus/kernel-2.4.6

+export LD_LIBRARY_PATH=/opt/Embedix/tools/lib/gcc-lib/arm-linux/2.95.2/

+export PATH=$PATH:/opt/Embedix/tools/bin

+export DESTDIR=/zaurus/binaries

+</pre>

+In the example above, we setup all of the usual gcc + bin-utils programs, 

+as well as setting the LD_LIBRARY_PATH to our cross-compiled system libraries, 

+and DESTDIR to our output directory.

+</P>

+

+<H3>Kernel Source</H3>

+<P>Place a copy of the kernel source, setup for your target device somewhere on

+your filesystem and set KERNELSRC= to this directory.  You will need to prepare 

+your kernel source treefirst, by running "make menuconfig && make dep && make 

+modules".  Once this is done, you can move on to building FreeS/WAN</P>

+

+<H2><A NAME="building"></A>Building</H2>

+<H3>The Make Process</H3>

+<P>There are two parts to building FreeS/WAN - the userland programs and utilities, 

+and the ipsec.o kernel module.  Each can be built seperatly, making debugging the

+build process simpler.

+</P>

+<P>Step 1 is to run "make programs".  This will build the required libs 

+(libfreeswan.a) as well as all of the userland tools (pluto, whack, etc...).  

+Provided your environment variables are set correctly, you should see the output

+using your specified gcc (arm-linux-gcc for our example), ld, as, ar and 

+ranlib.</P>

+<P>If this completes successfully, you can run "make install" to install a copy of

+all of the binaries, man pages and other documentation to DESTDIR.</P>

+<P>Step 2 is to build the ipsec.o module.  This is done with "make oldmod", which

+should change into the KERNELSRC directory and then compile and link the required

+files to generate an ipsec.o file.  If this is successful, you will end up with an

+ipsec.o file in your FreeS/WAN directory, under linux/net/ipsec/.</P>

+<P>Remember to install this to /lib/modules/$kernelversion/kernel/net/ipsec/ on 

+your target machine.</P>

+

+

+

+<H2><A NAME="common"></A>Common Problems Building</H2>

+<P>Here is a list of common problems/errors you may run into when cross compiling

+FreeS/WAN.</P>

+<UL>

+<LI>gmp.h, libgmp not found, error with -lgmp.  All of these refer to the GNU Math 

+Precision Library.  You will need to have already built this for your target 

+system.  Place libgmp.so in LD_LIBRARY_PATH, and ensure the headers are in your

+include path as well.

+</UL>

+

+<P><BR><BR>

+</P>

+</BODY>

+</HTML>

diff --git a/doc/src/draft-richardson-ipsec-opportunistic.html b/doc/src/draft-richardson-ipsec-opportunistic.html
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+<html><head><title>Opportunistic Encryption using The Internet Key Exchange (IKE)</title>
+<STYLE type='text/css'>
+    .title { color: #990000; font-size: 22px; line-height: 22px; font-weight: bold; text-align: right;
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+             font-family: verdana, charcoal, helvetica, arial, sans-serif }
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+           font-family: monaco, charcoal, geneva, MS Sans Serif, helvetica, monotype, verdana, sans-serif;
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+               font-family: charcoal, monaco, geneva, MS Sans Serif, helvetica, monotype, verdana, sans-serif;
+               font-size: 9px }
+</style>
+</head>
+<body bgcolor="#ffffff" text="#000000" alink="#000000" vlink="#666666" link="#990000">
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<table width="66%" border="0" cellpadding="0" cellspacing="0"><tr><td><table width="100%" border="0" cellpadding="2" cellspacing="1">
+<tr valign="top"><td width="33%" bgcolor="#666666" class="header">Independent submission</td><td width="33%" bgcolor="#666666" class="header">M. Richardson</td></tr>
+<tr valign="top"><td width="33%" bgcolor="#666666" class="header">Internet-Draft</td><td width="33%" bgcolor="#666666" class="header">SSW</td></tr>
+<tr valign="top"><td width="33%" bgcolor="#666666" class="header">Expires: November 19, 2003</td><td width="33%" bgcolor="#666666" class="header">D. Redelmeier</td></tr>
+<tr valign="top"><td width="33%" bgcolor="#666666" class="header">&nbsp;</td><td width="33%" bgcolor="#666666" class="header">Mimosa</td></tr>
+<tr valign="top"><td width="33%" bgcolor="#666666" class="header">&nbsp;</td><td width="33%" bgcolor="#666666" class="header">May 21, 2003</td></tr>
+</table></td></tr></table>
+<div align="right"><font face="monaco, MS Sans Serif" color="#990000" size="+3"><b><br><span class="title">Opportunistic Encryption using The Internet Key Exchange (IKE)</span></b></font></div>
+<div align="right"><font face="monaco, MS Sans Serif" color="#666666" size="+2"><b><span class="filename">draft-richardson-ipsec-opportunistic-11.txt</span></b></font></div>
+<font face="verdana, helvetica, arial, sans-serif" size="2">
+
+<h3>Status of this Memo</h3>
+<p>
+This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026.</p>
+<p>
+Internet-Drafts are working documents of the Internet Engineering
+Task Force (IETF), its areas, and its working groups.
+Note that other groups may also distribute working documents as
+Internet-Drafts.</p>
+<p>
+Internet-Drafts are draft documents valid for a maximum of six months
+and may be updated, replaced, or obsoleted by other documents at any time.
+It is inappropriate to use Internet-Drafts as reference material or to cite
+them other than as "work in progress."</p>
+<p>
+The list of current Internet-Drafts can be accessed at
+<a href='http://www.ietf.org/ietf/1id-abstracts.txt'>http://www.ietf.org/ietf/1id-abstracts.txt</a>.</p>
+<p>
+The list of Internet-Draft Shadow Directories can be accessed at
+<a href='http://www.ietf.org/shadow.html'>http://www.ietf.org/shadow.html</a>.</p>
+<p>
+This Internet-Draft will expire on November 19, 2003.</p>
+
+<h3>Copyright Notice</h3>
+<p>
+Copyright (C) The Internet Society (2003). All Rights Reserved.</p>
+
+<h3>Abstract</h3>
+
+<p>
+This document describes opportunistic encryption (OE) using the Internet Key
+Exchange (IKE) and IPsec.  
+Each system administrator adds new
+resource records to his or her Domain Name System (DNS) to support
+opportunistic encryption. The objective is to allow encryption for secure communication without
+any pre-arrangement specific to the pair of systems involved.
+  
+</p>
+<p>
+DNS is used to distribute the public keys of each
+system involved. This is resistant to passive attacks. The use of DNS
+Security (DNSSEC) secures this system against active attackers as well. 
+  
+</p>
+<p>
+As a result, the administrative overhead is reduced
+from the square of the number of systems to a linear dependence, and it becomes  
+possible to make secure communication the default even
+when the partner is not known in advance.
+  
+</p>
+<p>
+This document is offered up as an Informational RFC.
+  
+</p><a name="toc"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<h3>Table of Contents</h3>
+<ul compact class="toc">
+<b><a href="#anchor1">1.</a>&nbsp;
+Introduction<br></b>
+<b><a href="#anchor6">2.</a>&nbsp;
+Overview<br></b>
+<b><a href="#anchor13">3.</a>&nbsp;
+Specification<br></b>
+<b><a href="#anchor31">4.</a>&nbsp;
+Impacts on IKE<br></b>
+<b><a href="#anchor38">5.</a>&nbsp;
+DNS issues<br></b>
+<b><a href="#anchor42">6.</a>&nbsp;
+Network address translation interaction<br></b>
+<b><a href="#anchor46">7.</a>&nbsp;
+Host implementations<br></b>
+<b><a href="#anchor47">8.</a>&nbsp;
+Multi-homing<br></b>
+<b><a href="#anchor48">9.</a>&nbsp;
+Failure modes<br></b>
+<b><a href="#anchor52">10.</a>&nbsp;
+Unresolved issues<br></b>
+<b><a href="#anchor54">11.</a>&nbsp;
+Examples<br></b>
+<b><a href="#securityconsiderations">12.</a>&nbsp;
+Security considerations<br></b>
+<b><a href="#anchor79">13.</a>&nbsp;
+IANA Considerations<br></b>
+<b><a href="#anchor80">14.</a>&nbsp;
+Acknowledgments<br></b>
+<b><a href="#rfc.references1">&#167;</a>&nbsp;
+Normative references<br></b>
+<b><a href="#rfc.authors">&#167;</a>&nbsp;
+Authors' Addresses<br></b>
+<b><a href="#rfc.copyright">&#167;</a>&nbsp;
+Full Copyright Statement<br></b>
+</ul>
+<br clear="all">
+
+<a name="anchor1"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<a name="rfc.section.1"></a><h3>1.&nbsp;Introduction</h3>
+
+<a name="rfc.section.1.1"></a><h4><a name="anchor2">1.1</a>&nbsp;Motivation</h4>
+
+<p>
+The objective of opportunistic encryption is to allow encryption without
+any pre-arrangement specific to the pair of systems involved. Each
+system administrator adds
+public key information to DNS records to support opportunistic
+encryption and then enables this feature in the nodes' IPsec stack. 
+Once this is done, any two such nodes can communicate securely.
+
+</p>
+<p>
+This document describes opportunistic encryption as designed and
+mostly implemented by the Linux FreeS/WAN project.
+For project information, see http://www.freeswan.org.
+
+</p>
+<p>
+The Internet Architecture Board (IAB) and Internet Engineering
+Steering Group (IESG) have taken a strong stand that the Internet
+should use powerful encryption to provide security and
+privacy <a href="#RFC1984">[4]</a>.
+The Linux FreeS/WAN project attempts to provide a practical means to implement this policy. 
+  
+</p>
+<p>
+The project uses the IPsec, ISAKMP/IKE, DNS and DNSSEC
+protocols because they are
+standardized, widely available and can often be deployed very easily
+without changing hardware or software or retraining users. 
+  
+</p>
+<p>
+The extensions to support opportunistic encryption are simple.  No
+changes to any on-the-wire formats are needed.  The only changes are to 
+the policy decision making system.  This means that opportunistic
+encryption can be implemented with very minimal changes to an existing 
+IPsec implementation.
+  
+</p>
+<p>
+Opportunistic encryption creates a "fax effect". The proliferation
+of the fax machine was possible because it did not require that everyone
+buy one overnight. Instead, as each person installed one, the value
+of having one increased - as there were more people that could receive faxes.
+Once opportunistic encryption is installed it
+automatically recognizes 
+other boxes using opportunistic encryption, without any further configuration
+by the network 
+administrator. So, as opportunistic encryption software is installed on more
+boxes, its value 
+as a tool increases.
+
+</p>
+<p>
+This document describes the infrastructure to permit deployment of
+Opportunistic Encryption.
+
+</p>
+<p>
+The term S/WAN is a trademark of RSA Data Systems, and is used with permission
+by this project.
+  
+</p>
+<a name="rfc.section.1.2"></a><h4><a name="anchor3">1.2</a>&nbsp;Types of network traffic</h4>
+
+<p>
+    To aid in understanding the relationship between security processing and IPsec
+    we divide network traffic into four categories:
+    
+<blockquote class="text"><dl>
+<dt>* Deny:</dt>
+<dd> networks to which traffic is always forbidden.
+</dd>
+<dt>* Permit:</dt>
+<dd> networks to which traffic in the clear is permitted.
+</dd>
+<dt>* Opportunistic tunnel:</dt>
+<dd> networks to which traffic is encrypted if possible, but otherwise is in the clear  
+	    or fails depending on the default policy in place.	
+      
+</dd>
+<dt>* Configured tunnel:</dt>
+<dd> networks to which traffic must be encrypted, and traffic in the clear is never permitted.
+</dd>
+</dl></blockquote><p>
+</p>
+<p>
+Traditional firewall devices handle the first two categories. No authentication is required.
+The permit policy is currently the default on the Internet. 
+
+</p>
+<p>
+This document describes the third category - opportunistic tunnel, which is
+proposed as the new default for the Internet.
+
+</p>
+<p>
+  Category four, encrypt traffic or drop it, requires authentication of the
+  end points. As the number of end points is typically bounded and is typically
+  under a single authority, arranging for distribution of
+  authentication material, while difficult, does not require any new
+  technology. The mechanism described here provides an additional way to
+  distribute the authentication materials, that of a public key method that does not
+  require deployment of an X.509 based infrastructure.  
+
+</p>
+<p>
+Current Virtual Private Networks can often be replaced by an "OE paranoid"
+policy as described herein. 
+
+</p>
+<a name="rfc.section.1.3"></a><h4><a name="anchor4">1.3</a>&nbsp;Peer authentication in opportunistic encryption</h4>
+
+<p>
+  Opportunistic encryption creates tunnels between nodes that
+  are essentially strangers. This is done without any prior bilateral
+  arrangement. 
+  There is, therefore, the difficult question of how one knows to whom one is
+  talking.
+  
+</p>
+<p>
+  One possible answer is that since no useful
+  authentication can be done, none should be tried. This mode of operation is
+  named "anonymous encryption".  An active man-in-the-middle attack can be
+  used to thwart the privacy of this type of communication. 
+  Without peer authentication, there is no way to prevent this kind of attack.
+  
+</p>
+<p>
+Although a useful mode, anonymous encryption is not the goal of this
+project. Simpler methods are available that can achieve anonymous
+encryption only, but authentication of the peer is a desireable goal.
+The latter is achieved through key distribution in DNS, leveraging upon
+the authentication of the DNS in DNSSEC.
+
+</p>
+<p>
+  Peers are, therefore, authenticated with DNSSEC when available. Local policy 
+determines how much trust to extend when DNSSEC is not available.
+  
+</p>
+<p>
+  However, an essential premise of building private connections with
+  strangers is that datagrams received through opportunistic tunnels
+  are no more special than datagrams that arrive in the clear.
+  Unlike in a VPN, these datagrams should not be given any special
+  exceptions when it comes to auditing, further authentication or
+  firewalling.
+  
+</p>
+<p>
+  When initiating outbound opportunistic encryption, local 
+  configuration determines what happens if tunnel setup fails. It may be that
+  the packet goes out in the clear, or it may be dropped.
+  
+</p>
+<a name="rfc.section.1.4"></a><h4><a name="anchor5">1.4</a>&nbsp;Use of RFC2119 terms</h4>
+
+<p>
+   The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
+   SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this
+   document, are to be interpreted as described in <a href="#RFC2119">[5]</a>
+</p>
+<a name="anchor6"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<a name="rfc.section.2"></a><h3>2.&nbsp;Overview</h3>
+
+<a name="rfc.section.2.1"></a><h4><a name="anchor7">2.1</a>&nbsp;Reference diagram</h4>
+<br><hr size="1" shade="0">
+<a name="networkdiagram"></a>
+
+<p>The following network diagram is used in the rest of
+		this document as the canonical diagram:
+</p></font><pre>
+                          [Q]  [R]          
+                           .    .              AS2                 
+  [A]----+----[SG-A].......+....+.......[SG-B]-------[B]
+         |                 ......
+     AS1 |                 ..PI..
+         |                 ......
+  [D]----+----[SG-D].......+....+.......[C] AS3
+             
+
+           </pre><font face="verdana, helvetica, arial, sans-serif" size="2">
+
+<p>
+</p><table border="0" cellpadding="0" cellspacing="2" align="center"><tr><td align="center"><font face="monaco, MS Sans Serif" size="1"><b>&nbsp;Reference Network Diagram&nbsp;</b></font><br></td></tr></table><hr size="1" shade="0">
+
+<p>
+    In this diagram, there are four end-nodes: A, B, C and D. 
+    There are three gateways, SG-A, SG-B, SG-D. A, D, SG-A and SG-D are part
+    of the same administrative authority, AS1. SG-A and SG-D are on two different exit
+    paths from organization 1. SG-B/B is an independent organization, AS2.
+    Nodes Q and R are nodes on the Internet. PI is the Public
+    Internet ("The Wild").
+    
+</p>
+<a name="rfc.section.2.2"></a><h4><a name="anchor8">2.2</a>&nbsp;Terminology</h4>
+
+<p>
+  The following terminology is used in this document:
+  
+</p>
+<blockquote class="text"><dl>
+<dt>Security gateway:</dt>
+<dd> a system that performs IPsec tunnel
+    mode encapsulation/decapsulation. [SG-x] in the diagram.
+</dd>
+<dt>Alice:</dt>
+<dd> node [A] in the diagram. When an IP address is needed, this is 192.1.0.65.
+</dd>
+<dt>Bob:</dt>
+<dd> node [B] in the diagram. When an IP address is needed, this is 192.2.0.66.
+</dd>
+<dt>Carol:</dt>
+<dd> node [C] in the diagram. When an IP address is needed, this is 192.1.1.67.
+</dd>
+<dt>Dave:</dt>
+<dd> node [D] in the diagram. When an IP address is needed, this is 192.3.0.68.
+</dd>
+<dt>SG-A:</dt>
+<dd> Alice's security gateway. Internally it is 192.1.0.1, externally it is 192.1.1.4.
+</dd>
+<dt>SG-B:</dt>
+<dd> Bob's security gateway. Internally it is 192.2.0.1, externally it is 192.1.1.5.
+</dd>
+<dt>SG-D:</dt>
+<dd> Dave's security gateway. Also Alice's backup security gateway. Internally it is 192.3.0.1, externally it is 192.1.1.6.
+</dd>
+<dt>-</dt>
+<dd> A single dash represents clear-text datagrams.
+</dd>
+<dt>=</dt>
+<dd> An equals sign represents phase 2 (IPsec) cipher-text
+        datagrams.
+</dd>
+<dt>~</dt>
+<dd> A single tilde represents clear-text phase 1 datagrams.
+</dd>
+<dt>#</dt>
+<dd> A hash sign represents phase 1 (IKE) cipher-text
+        datagrams.
+</dd>
+<dt>.</dt>
+<dd> A period represents an untrusted network of unknown
+        type.
+</dd>
+<dt>Configured tunnel:</dt>
+<dd> a tunnel that
+		  is directly and deliberately hand configured on participating gateways.
+		  Configured tunnels are typically given a higher level of
+		  trust than opportunistic tunnels.
+</dd>
+<dt>Road warrior tunnel:</dt>
+<dd> a configured tunnel connecting one
+		  node with a fixed IP address and one node with a variable IP address.
+		  A road warrior (RW) connection must be initiated by the
+		  variable node, since the fixed node cannot know the
+		  current address for the road warrior. 
+</dd>
+<dt>Anonymous encryption:</dt>
+<dd>
+	the process of encrypting a session without any knowledge of who the
+	other parties are. No authentication of identities is done.
+</dd>
+<dt>Opportunistic encryption:</dt>
+<dd>
+	the process of encrypting a session with authenticated knowledge of
+	who the other parties are.
+</dd>
+<dt>Lifetime:</dt>
+<dd>
+        the period in seconds (bytes or datagrams) for which a security
+	association will remain alive before needing to be re-keyed.
+</dd>
+<dt>Lifespan:</dt>
+<dd>
+        the effective time for which a security association remains useful. A
+	security association with a lifespan shorter than its lifetime would
+	be removed when no longer needed. A security association with a
+	lifespan longer than its lifetime would need to be re-keyed one or
+	more times.
+</dd>
+<dt>Phase 1 SA:</dt>
+<dd> an ISAKMP/IKE security association sometimes
+      referred to as a keying channel.
+</dd>
+<dt>Phase 2 SA:</dt>
+<dd> an IPsec security association.
+</dd>
+<dt>Tunnel:</dt>
+<dd> another term for a set of phase 2 SA (one in each direction).
+</dd>
+<dt>NAT:</dt>
+<dd> Network Address Translation
+    (see <a href="#RFC2663">[20]</a>).
+</dd>
+<dt>NAPT:</dt>
+<dd> Network Address and Port Translation
+    (see <a href="#RFC2663">[20]</a>).
+</dd>
+<dt>AS:</dt>
+<dd> an autonomous system (AS) is a group of systems (a network) that
+		are under the administrative control of a single organization.
+</dd>
+<dt>Default-free zone:</dt>
+<dd> 
+    a set of routers that maintain a complete set of routes to
+    all currently reachable destinations. Having such a list, these routers
+    never make use of a default route. A datagram with a destination address
+    not matching any route will be dropped by such a router.
+    
+</dd>
+</dl></blockquote><p>
+<a name="rfc.section.2.3"></a><h4><a name="anchor9">2.3</a>&nbsp;Model of operation</h4>
+
+<p>
+The opportunistic encryption security gateway (OE gateway) is a regular
+gateway node as described in <a href="#RFC0791">[2]</a> section 2.4 and  
+<a href="#RFC1009">[3]</a> with the additional capabilities described here and
+in <a href="#RFC2401">[7]</a>.  
+The algorithm described here provides a way to determine, for each datagram,
+whether or not to encrypt and tunnel the datagram. Two important things
+that must be determined are whether or not to encrypt and tunnel and, if
+so, the destination address or name of the tunnel end point which should be used. 
+
+</p>
+<a name="rfc.section.2.3.1"></a><h4><a name="anchor10">2.3.1</a>&nbsp;Tunnel authorization</h4>
+
+<p>
+The OE gateway determines whether or not to create a tunnel based on 
+the destination address of each packet. Upon receiving a packet with a destination
+address not recently seen, the OE gateway performs a lookup in DNS for an
+authorization resource record (see <a href="#TXT">Use of TXT delegation record</a>). The record is located using
+the IP address to perform a search in the in-addr.arpa (IPv4) or ip6.arpa
+(IPv6) maps. If an authorization record is found, the OE gateway 
+interprets this as a request for a tunnel to be formed.
+
+</p>
+<a name="rfc.section.2.3.2"></a><h4><a name="anchor11">2.3.2</a>&nbsp;Tunnel end-point discovery</h4>
+
+<p>
+The authorization resource record also provides the address or name of the tunnel
+end point which should be used.
+
+</p>
+<p>
+The record may also provide the public RSA key of the tunnel end point
+itself. This is provided for efficiency only. If the public RSA key is not 
+present, the OE gateway performs a second lookup to find a KEY 
+resource record for the end point address or name.
+
+</p>
+<p>
+Origin and integrity protection of the resource records is provided by 
+DNSSEC (<a href="#RFC2535">[16]</a>). <a href="#nodnssec">Restriction on unauthenticated TXT delegation records</a>
+documents an optional restriction on the tunnel end point if DNSSEC signatures
+are not available for the relevant records. 
+
+</p>
+<a name="rfc.section.2.3.3"></a><h4><a name="anchor12">2.3.3</a>&nbsp;Caching of authorization results</h4>
+
+<p>
+The OE gateway maintains a cache, in the forwarding plane, of
+source/destination pairs for which opportunistic encryption has been
+attempted. This cache maintains a record of whether or not OE was
+successful so that subsequent datagrams can be forwarded properly
+without additional delay. 
+
+</p>
+<p>
+Successful negotiation of OE instantiates a new security association. 
+Failure to negotiate OE results in creation of a 
+forwarding policy entry either to drop or transmit in the clear future
+datagrams. This negative cache is necessary to avoid the possibly lengthy process of repeatedly looking 
+up the same information.
+
+</p>
+<p>
+The cache is timed out periodically, as described in <a href="#teardown">Renewal and teardown</a>.
+This removes entries that are no longer
+being used and permits the discovery of changes in authorization policy.
+
+</p>
+<a name="anchor13"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<a name="rfc.section.3"></a><h3>3.&nbsp;Specification</h3>
+
+<p>
+The OE gateway is modeled to have a forwarding plane and a control
+plane. A control channel, such as PF_KEY, connects the two planes. 
+(See <a href="#RFC2367">[6]</a>.)
+The forwarding plane performs per datagram operations. The control plane
+contains a keying 
+daemon, such as ISAKMP/IKE, and performs all authorization, peer authentication and
+key derivation functions.  
+
+</p>
+<a name="rfc.section.3.1"></a><h4><a name="anchor14">3.1</a>&nbsp;Datagram state machine</h4>
+
+<p>
+Let the OE gateway maintain a collection of objects -- a superset of the
+security policy database (SPD) specified in <a href="#RFC2401">[7]</a>. For
+each combination of source and destination address, an SPD
+object exists in one of five following states.
+Prior to forwarding each datagram, the
+responder uses the source and destination addresses to pick an entry from the SPD.
+The SPD then determines if and how the packet is forwarded.
+
+</p>
+<a name="rfc.section.3.1.1"></a><h4><a name="anchor15">3.1.1</a>&nbsp;Non-existent policy</h4>
+
+<p>
+If the responder does not find an entry, then this policy applies.
+The responder creates an entry with an initial state of "hold policy" and requests 
+keying material from the keying daemon. The responder does not forward the datagram,
+rather it attaches the datagram to the SPD entry as the  "first" datagram and retains it
+for eventual transmission in a new state. 
+
+
+</p>
+<a name="rfc.section.3.1.2"></a><h4><a name="anchor16">3.1.2</a>&nbsp;Hold policy</h4>
+
+<p>
+The responder requests keying material. If the interface to the keying
+system is lossy (PF_KEY, for instance, can be), the implementation 
+SHOULD include a mechanism to retransmit the
+keying request at a rate limited to less than 1 request per second.
+The responder does not forward the datagram. It attaches the 
+datagram to the SPD entry as the "last" datagram where it is retained 
+for eventual transmission. If there is
+a datagram already so stored, then that already stored datagram is discarded.
+
+</p>
+<p>
+Because the "first" datagram is probably a TCP SYN packet, the 
+responder retains the "first" datagram in an attempt to avoid waiting for a
+TCP retransmit. The responder retains the "last"
+datagram in deference to streaming protocols that find it useful to know
+how much data has been lost. These are recommendations to 
+decrease latency. There are no operational requirements for this.
+
+</p>
+<a name="rfc.section.3.1.3"></a><h4><a name="anchor17">3.1.3</a>&nbsp;Pass-through policy</h4>
+
+<p>
+The responder forwards the datagram using the normal forwarding table. 
+The responder enters this state only by command from the keying daemon, 
+and upon entering this state, also forwards the "first" and "last" datagrams.
+
+</p>
+<a name="rfc.section.3.1.4"></a><h4><a name="anchor18">3.1.4</a>&nbsp;Deny policy</h4>
+
+<p>
+The responder discards the datagram. The responder enters this state only by
+command  
+from the keying daemon, and upon entering this state, discards the "first"
+and "last" datagrams.  
+Local administration decides if further datagrams cause ICMP messages
+to be generated (i.e. ICMP Destination Unreachable, Communication
+Administratively Prohibited. type=3, code=13). 
+
+</p>
+<a name="rfc.section.3.1.5"></a><h4><a name="anchor19">3.1.5</a>&nbsp;Encrypt policy</h4>
+
+<p>
+The responder encrypts the datagram using the indicated security association database
+(SAD) entry.  The responder enters this state only by command from the keying daemon, and upon entering
+this state, releases and forwards the "first" and "last" datagrams using the
+new encrypt policy.  
+
+</p>
+<p>
+If the associated SAD entry expires because of byte, packet or time limits, then
+the entry returns to the Hold policy, and an expire message is sent to the keying daemon.
+
+</p>
+<p>
+All states may be created directly by the keying daemon while acting as a
+responder. 
+
+</p>
+<a name="rfc.section.3.2"></a><h4><a name="initclasses">3.2</a>&nbsp;Keying state machine - initiator</h4>
+
+<p>
+Let the keying daemon maintain a collection of objects. Let them be
+called "connections" or "conn"s. There are two categories of
+connection objects: classes and instances. A class represents an
+abstract policy - what could be. An instance represents an actual connection -  
+what is implemented at the time.
+
+</p>
+<p>
+Let there be two further subtypes of connections: keying channels (Phase
+1 SAs) and data channels (Phase 2 SAs). Each data channel object may have 
+a corresponding SPD and SAD entry maintained by the datagram state machine.
+
+</p>
+<p>
+For the purposes of opportunistic encryption, there MUST, at least, be
+connection classes known as "deny", "always-clear-text", "OE-permissive", and 
+"OE-paranoid".  
+The latter two connection classes define a set of source and/or destination
+addresses for which opportunistic encryption will be attempted. The administrator MAY set policy
+options in a number of additional places.  An implementation MAY create additional connection classes to further refine
+these policies.
+
+</p>
+<p>
+The simplest system may need only the "OE-permissive" connection, and would
+list its own (single) IP address as the source address of this policy and
+the wild-card address 0.0.0.0/0 as the destination IPv4 address. That is, the
+simplest policy is to try opportunistic encryption with all destinations. 
+
+</p>
+<p>
+The distinction between permissive and paranoid OE use will become clear 
+in the state transition differences. In general a permissive OE will, on
+failure, install a pass-through policy, while a paranoid OE will, on failure, 
+install a drop policy.
+
+</p>
+<p>
+In this description of the keying machine's state transitions, the states
+associated with the keying system itself are omitted because they are best documented in the keying system 
+(<a href="#RFC2407">[8]</a>, 
+<a href="#RFC2408">[9]</a> and <a href="#RFC2409">[10]</a> for ISAKMP/IKE),
+and the details are keying system specific. Opportunistic encryption is not
+dependent upon any specific keying protocol, but this document does provide
+requirements for those using ISAKMP/IKE to assure that implementations inter-operate.
+
+</p>
+<p>
+The state transitions that may be involved in communicating with the
+forwarding plane are omitted. PF_KEY and similar protocols have their own
+set of states required for message sends and completion notifications.
+
+</p>
+<p>
+Finally, the retransmits and recursive lookups that are normal for DNS are 
+not included in this description of the state machine.
+
+</p>
+<a name="rfc.section.3.2.1"></a><h4><a name="anchor20">3.2.1</a>&nbsp;Nonexistent connection</h4>
+
+<p>
+There is no connection instance for a given source/destination address pair.
+Upon receipt of a request for keying material for this
+source/destination pair, the initiator searches through the connection classes to
+determine the most appropriate policy. Upon determining an appropriate
+connection class, an instance object is created of that type. 
+Both of the OE types result in a potential OE connection.
+
+</p>
+<p>Failure to find an appropriate connection class results in an
+administrator defined default. 
+
+</p>
+<p>
+In each case, when the initiator finds an appropriate class for the new flow, 
+an instance connection is made of the class which matched.
+
+</p>
+<a name="rfc.section.3.2.2"></a><h4><a name="anchor21">3.2.2</a>&nbsp;Clear-text connection</h4>
+
+<p>
+The non-existent connection makes a transition to this state when an
+always-clear-text class is instantiated, or when an OE-permissive 
+connection fails. During the transition, the initiator creates a pass-through
+policy object in the forwarding plane for the appropriate flow.
+
+</p>
+<p>
+Timing out is the only way to leave this state
+(see <a href="#expiring">Expiring connection</a>).
+
+</p>
+<a name="rfc.section.3.2.3"></a><h4><a name="anchor22">3.2.3</a>&nbsp;Deny connection</h4>
+
+<p>
+The empty connection makes a transition to this state when a
+deny class is instantiated, or when an OE-paranoid connection fails. 
+During the transition, the initiator creates a deny policy object in the forwarding plane 
+for the appropriate flow.  
+
+</p>
+<p>
+Timing out is the only way to leave this state 
+(see <a href="#expiring">Expiring connection</a>).
+
+</p>
+<a name="rfc.section.3.2.4"></a><h4><a name="anchor23">3.2.4</a>&nbsp;Potential OE connection</h4>
+
+<p>
+The empty connection makes a transition to this state when one of either OE class is instantiated.
+During the transition to this state, the initiator creates a hold policy object in the 
+forwarding plane for the appropriate flow.  
+
+</p>
+<p>
+In addition, when making a transition into this state, DNS lookup is done in
+the reverse-map for a TXT delegation resource record (see <a href="#TXT">Use of TXT delegation record</a>).
+The lookup key is the destination address of the flow.
+
+</p>
+<p>
+There are three ways to exit this state: 
+
+<ol class="text">
+<li>DNS lookup finds a TXT delegation resource record.
+</li>
+<li>DNS lookup does not find a TXT delegation resource record.
+</li>
+<li>DNS lookup times out.
+</li>
+</ol><p>
+</p>
+<p>
+Based upon the results of the DNS lookup, the potential OE connection makes a
+transition to the pending OE connection state.  The conditions for a
+successful DNS look are:
+
+<ol class="text">
+<li>DNS finds an appropriate resource record
+</li>
+<li>It is properly formatted according to <a href="#TXT">Use of TXT delegation record</a>
+</li>
+<li> if DNSSEC is enabled, then the signature has been vouched for.
+</li>
+</ol><p>
+
+Note that if the initiator does not find the public key 
+present in the TXT delegation record, then the public key must 
+be looked up as a sub-state. Only successful completion of all the 
+DNS lookups is considered a success.
+
+</p>
+<p>
+If DNS lookup does not find a resource record or DNS times out, then the 
+initiator considers the receiver not OE capable. If this is an OE-paranoid instance, 
+then the potential OE connection makes a transition to the deny connection state.
+If this is an OE-permissive instance, then the potential OE connection makes a transition to the
+clear-text connection state.
+
+</p>
+<p>
+If the initiator finds a resource record but it is not properly formatted, or
+if DNSSEC is 
+enabled and reports a failure to authenticate, then the potential OE
+connection should make a 
+transition to the deny connection state. This action SHOULD be logged. If the
+administrator wishes to override this transition between states, then an
+always-clear class can be installed for this flow. An implementation MAY make
+this situation a new class.
+
+</p>
+<a name="rfc.section.3.2.4.1"></a><h4><a name="nodnssec">3.2.4.1</a>&nbsp;Restriction on unauthenticated TXT delegation records</h4>
+
+<p>
+An implementation SHOULD also provide an additional administrative control
+on delegation records and DNSSEC. This control would apply to delegation
+records (the TXT records in the reverse-map) that are not protected by
+DNSSEC.
+Records of this type are only permitted to delegate to their own address as
+a gateway. When this option is enabled, an active attack on DNS will be
+unable to redirect packets to other than the original destination.
+
+</p>
+<a name="rfc.section.3.2.5"></a><h4><a name="anchor24">3.2.5</a>&nbsp;Pending OE connection</h4>
+
+<p>
+The potential OE connection makes a transition to this state when 
+the initiator determines that all the information required from the DNS lookup is present.
+Upon entering this state, the initiator attempts to initiate keying to the gateway
+provided.  
+
+</p>
+<p>
+Exit from this state occurs either with a successfully created IPsec SA, or
+with a failure of some kind.  Successful SA creation results in a transition
+to the key connection state.
+
+</p>
+<p>
+Three failures have caused significant problems. They are clearly not the
+only possible failures from keying.
+
+</p>
+<p>
+Note that if there are multiple gateways available in the TXT delegation
+records, then a failure can only be declared after all have been
+tried. Further, creation of a phase 1 SA does not constitute success. A set
+of phase 2 SAs (a tunnel) is considered success.
+
+</p>
+<p>
+The first failure occurs when an ICMP port unreachable is consistently received
+without any other communication, or when there is silence from the remote
+end. This usually means that either the gateway is not alive, or the
+keying daemon is not functional. For an OE-permissive connection, the initiator makes a transition
+to the clear-text connection but with a low lifespan. For an OE-pessimistic connection,
+the initiator makes a transition to the deny connection again with a low lifespan. The lifespan in both 
+cases is kept low because the remote gateway may
+be in the process of rebooting or be otherwise temporarily unavailable. 
+
+</p>
+<p>
+The length of time to wait for the remote keying daemon to wake up is
+a matter of some debate. If there is a routing failure, 5 minutes is usually long enough for the network to
+re-converge. Many systems can reboot in that amount of
+time as well. However, 5 minutes is far too long for most users to wait to
+hear that they can not connect using OE. Implementations SHOULD make this a
+tunable parameter.
+
+</p>
+<p>
+The second failure occurs after a phase 1 SA has been created, but there is 
+either no response to the phase 2 proposal, or the initiator receives a 
+negative notify (the notify must be 
+authenticated). The remote gateway is not prepared to do OE at this time. 
+As before, the initiator makes a transition to the clear-text or the deny 
+connection based upon connection class, but this
+time with a normal lifespan. 
+
+</p>
+<p>
+The third failure occurs when there is signature failure while authenticating
+the remote gateway. This can occur when there has been a 
+key roll-over, but DNS has not caught up. In this case again, the initiator makes a 
+transition to the clear-text or the deny connection based
+upon the connection class. However, the lifespan depends upon the remaining
+time to live in the DNS. (Note that DNSSEC signed resource records have a different
+expiry time than non-signed records.) 
+
+</p>
+<a name="rfc.section.3.2.6"></a><h4><a name="keyed">3.2.6</a>&nbsp;Keyed connection</h4>
+
+<p>
+The pending OE connection makes a transition to this state when 
+session keying material (the phase 2 SAs) is derived. The initiator creates an encrypt
+policy in the forwarding plane for this flow.
+
+</p>
+<p>
+There are three ways to exit this state. The first is by receipt of an
+authenticated delete message (via the keying channel) from the peer. This is
+normal teardown and results in a transition to the expired connection state.
+
+</p>
+<p>
+The second exit is by expiry of the forwarding plane keying material. This
+starts a re-key operation with a transition back to pending OE
+connection. In general, the soft expiry occurs with sufficient time left
+to continue to use the keys. A re-key can fail, which may
+result in the connection failing to clear-text or deny as
+appropriate. In the event of a failure, the forwarding plane
+policy does not change until the phase 2 SA (IPsec SA) reaches its
+hard expiry.
+
+</p>
+<p>
+The third exit is in response to a negotiation from a remote
+gateway. If the forwarding plane signals the control plane that it has received an
+unknown SPI from the remote gateway, or an ICMP is received from the remote gateway
+indicating an unknown SPI, the initiator should consider that 
+the remote gateway has rebooted or restarted. Since these 
+indications are easily forged, the implementation must 
+exercise care.  The initiator should make a cautious 
+(rate-limited) attempt to re-key the connection. 
+
+</p>
+<a name="rfc.section.3.2.7"></a><h4><a name="expiring">3.2.7</a>&nbsp;Expiring connection</h4>
+
+<p>
+The initiator will periodically place each of the deny, clear-text, and keyed
+connections into this  
+sub-state. See <a href="#teardown">Renewal and teardown</a> for more details of how often this
+occurs. 
+The initiator queries the forwarding plane for last use time of the
+appropriate 
+policy. If the last use time is relatively recent, then the connection
+returns to the 
+previous deny, clear-text or keyed connection state. If not, then the
+connection enters 
+the expired connection state. 
+
+</p>
+<p>
+The DNS query and answer that lead to the expiring connection state are also
+examined. The DNS query may become stale. (A negative, i.e. no such record, answer
+is valid for the period of time given by the MINIMUM field in an attached SOA 
+record. See <a href="#RFC1034">[12]</a> section 4.3.4.)
+If the DNS query is stale, then a new query is made. If the results change, then the connection 
+makes a transition to a new state as described in potential OE connection state.
+
+</p>
+<p> 
+Note that when considering how stale a connection is, both outgoing SPD and
+incoming SAD must be queried as some flows may be unidirectional for some time.
+
+</p>
+<p>
+Also note that the policy at the forwarding plane is not updated unless there
+is a conclusion that there should be a change.
+
+</p>
+<a name="rfc.section.3.2.8"></a><h4><a name="anchor25">3.2.8</a>&nbsp;Expired connection</h4>
+
+<p>
+Entry to this state occurs when no datagrams have been forwarded recently via the
+appropriate SPD and SAD objects. The objects in the forwarding plane are
+removed (logging any final byte and packet counts if appropriate) and the
+connection instance in the keying plane is deleted. 
+
+</p>
+<p>
+The initiator sends an ISAKMP/IKE delete to clean up the phase 2 SAs as described in
+<a href="#teardown">Renewal and teardown</a>. 
+
+</p>
+<p>
+Whether or not to delete the phase 1 SAs
+at this time is left as a local implementation issue. Implementations
+that do delete the phase 1 SAs MUST send authenticated delete messages to
+indicate that they are doing so.  There is an advantage to keeping
+the phase 1 SAs until they expire - they may prove useful again in the 
+near future.
+
+</p>
+<a name="rfc.section.3.3"></a><h4><a name="anchor26">3.3</a>&nbsp;Keying state machine - responder</h4>
+
+<p>
+The responder has a set of objects identical to those of the initiator.
+
+</p>
+<p>
+The responder receives an invitation to create a keying channel from an initiator. 
+
+</p>
+<a name="rfc.section.3.3.1"></a><h4><a name="anchor27">3.3.1</a>&nbsp;Unauthenticated OE peer</h4>
+
+<p>
+Upon entering this state, the responder starts a DNS lookup for a KEY record for the
+initiator. 
+The responder looks in the reverse-map for a KEY record for the initiator if the
+initiator has offered an ID_IPV4_ADDR, and in the forward map if the
+initiator has offered an ID_FQDN type. (See <a href="#RFC2407">[8]</a> section 
+4.6.2.1.)
+
+</p>
+<p>
+The responder exits this state upon successful receipt of a KEY from DNS, and use of the key 
+to verify the signature of the initiator.
+
+</p>
+<p>
+Successful authentication of the peer results in a transition to the
+authenticated OE Peer state.
+
+</p>
+<p>
+Note that the unauthenticated OE peer state generally occurs in the middle of the key negotiation
+protocol. It is really a form of pseudo-state.
+
+</p>
+<a name="rfc.section.3.3.2"></a><h4><a name="anchor28">3.3.2</a>&nbsp;Authenticated OE Peer</h4>
+
+<p>
+The peer will eventually propose one or more phase 2 SAs. The responder uses the source and
+destination address in the proposal to 
+finish instantiating the connection state
+using the connection class table.
+The responder MUST search for an identical connection object at this point. 
+
+</p>
+<p> 
+If an identical connection is found, then the responder deletes the old instance, 
+and the new object makes a transition to the pending OE connection state. This means
+that new ISAKMP connections with a given peer will always use the latest
+instance, which is the correct one if the peer has rebooted in the interim.
+
+</p>
+<p> 
+If an identical connection is not found, then the responder makes the transition according to the 
+rules given for the initiator.
+
+</p>
+<p> 
+Note that if the initiator is in OE-paranoid mode and the responder is in 
+either always-clear-text or deny, then no communication is possible according
+to policy. An implementation is permitted to create new types of policies 
+such as "accept OE but do not initiate it". This is a local matter.
+ 
+</p>
+<a name="rfc.section.3.4"></a><h4><a name="teardown">3.4</a>&nbsp;Renewal and teardown</h4>
+
+<a name="rfc.section.3.4.1"></a><h4><a name="anchor29">3.4.1</a>&nbsp;Aging</h4>
+
+<p>
+A potentially unlimited number of tunnels may exist. In practice, only a few
+tunnels are used during a period of time. Unused tunnels MUST, therefore, be
+torn down. Detecting when tunnels are no longer in use is the subject of this section.
+
+</p>
+<p>
+There are two methods for removing tunnels: explicit deletion or expiry. 
+
+</p>
+<p>
+Explicit deletion requires an IKE delete message. As the deletes
+MUST be authenticated, both ends of the tunnel must maintain the 
+key channel (phase 1 ISAKMP SA). An implementation which refuses to either maintain or
+recreate the keying channel SA will be unable to use this method.
+
+</p>
+<p>
+The tunnel expiry method, simply allows the IKE daemon to
+expire normally without attempting to re-key it.
+
+</p>
+<p>
+Regardless of which method is used to remove tunnels, the implementation requires 
+a method to determine if the tunnel is still in use.  The specifics are a
+local matter, but  the FreeS/WAN project uses the following criteria. These
+criteria are currently implemented in the key management daemon, but could
+also be implemented at the SPD layer using an idle timer.
+
+</p>
+<p>
+Set a short initial (soft) lifespan of 1 minute since many net flows last
+only a few seconds.
+
+</p>
+<p>
+At the end of the lifespan, check to see if the tunnel was used by
+traffic in either direction during the last 30 seconds. If so, assign a
+longer tentative lifespan of 20 minutes after which, look again. If the
+tunnel is not in use, then close the tunnel.
+
+</p>
+<p>
+The expiring state in the key management
+system (see <a href="#expiring">Expiring connection</a>) implements these timeouts.
+The timer above may be in the forwarding plane, 
+but then it must be re-settable. 
+
+</p>
+<p>
+The tentative lifespan is independent of re-keying; it is just the time when
+the tunnel's future is next considered. 
+(The term lifespan is used here rather than lifetime for this reason.) 
+Unlike re-keying, this tunnel use check is not costly and should happen
+reasonably frequently.
+
+</p>
+<p>
+A multi-step back-off algorithm is not considered worth the effort here.
+
+</p>
+<p>
+If the security gateway and the client host are the
+same and not a Bump-in-the-Stack or Bump-in-the-Wire implementation, tunnel
+teardown decisions MAY pay attention to TCP connection status as reported
+by the local TCP layer.  A still-open TCP connection is almost a guarantee that more traffic is
+expected. Closing of the only TCP connection through a tunnel is a
+strong hint that no more traffic is expected.
+
+</p>
+<a name="rfc.section.3.4.2"></a><h4><a name="anchor30">3.4.2</a>&nbsp;Teardown and cleanup</h4>
+
+<p>
+Teardown should always be coordinated between the two ends of the tunnel by 
+interpreting and sending delete notifications. There is a
+detailed sub-state in the expired connection state of the key manager that
+relates to retransmits of the delete notifications, but this is considered to 
+be a keying system detail.
+
+</p>
+<p>
+On receiving a delete for the outbound SAs of a tunnel (or some subset of
+them), tear down the inbound ones also and notify the remote end with a
+delete. If the local system receives a delete for a tunnel which is no longer in
+existence, then two delete messages have crossed paths. Ignore the delete.
+The operation has already been completed. Do not generate any messages in this
+situation. 
+
+</p>
+<p>
+Tunnels are to be considered as bidirectional entities, even though the
+low-level protocols don't treat them this way. 
+
+</p>
+<p>
+When the deletion is initiated locally, rather than as a
+response to a received delete, send a delete for (all) the
+inbound SAs of a tunnel.  If the local system does not receive a responding delete 
+for the outbound SAs, try re-sending the original
+delete. Three tries spaced 10 seconds apart seems a reasonable
+level of effort. A failure of the other end to respond after 3 attempts, 
+indicates that the possibility of further communication is unlikely. Remove the outgoing SAs.
+(The remote system may be a mobile node that is no longer present or powered on.)
+
+</p>
+<p>
+After re-keying, transmission should switch to using the new
+outgoing SAs (ISAKMP or IPsec) immediately, and the old leftover
+outgoing SAs should be cleared out promptly (delete should be sent
+for the outgoing SAs) rather than waiting for them to expire. This
+reduces clutter and minimizes confusion for the operator doing diagnostics.
+
+</p>
+<a name="anchor31"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<a name="rfc.section.4"></a><h3>4.&nbsp;Impacts on IKE</h3>
+
+<a name="rfc.section.4.1"></a><h4><a name="anchor32">4.1</a>&nbsp;ISAKMP/IKE protocol</h4>
+
+<p>
+    The IKE wire protocol needs no modifications. The major changes are
+    implementation issues relating to how the proposals are interpreted, and from
+    whom they may come.
+    
+</p>
+<p>
+    As opportunistic encryption is designed to be useful between peers without
+    prior operator configuration, an IKE daemon must be prepared to negotiate
+    phase 1 SAs with any node. This may require a large amount of resources to 
+    maintain cookie state, as well as large amounts of entropy for nonces,
+    cookies and so on. 
+    
+</p>
+<p>
+    The major changes to support opportunistic encryption are at the IKE daemon
+    level. These changes relate to handling of key acquisition requests, lookup
+    of public keys and TXT records, and interactions with firewalls and other
+    security facilities that may be co-resident on the same gateway.
+    
+</p>
+<a name="rfc.section.4.2"></a><h4><a name="anchor33">4.2</a>&nbsp;Gateway discovery process</h4>
+
+<p>
+  In a typical configured tunnel, the address of SG-B is provided
+  via configuration. Furthermore, the mapping of an SPD entry to a gateway is
+  typically a 1:1 mapping. When the 0.0.0.0/0 SPD entry technique is used, then
+  the mapping to a gateway is determined by the reverse DNS records.
+  
+</p>
+<p>
+  The need to do a DNS lookup and wait for a reply will typically introduce a
+  new state and a new event source (DNS replies) to IKE. Although a
+synchronous DNS request can be implemented for proof of concept, experience
+is that it can cause very high latencies when a queue of queries must
+all timeout in series. 
+  
+</p>
+<p> 
+  Use of an asynchronous DNS lookup will also permit overlap of DNS lookups with
+  some of the protocol steps.
+  
+</p>
+<a name="rfc.section.4.3"></a><h4><a name="anchor34">4.3</a>&nbsp;Self identification</h4>
+
+<p>
+     SG-A will have to establish its identity. Use an
+     IPv4 ID in phase 1. 
+  
+</p>
+<p> There are many situations where the administrator of SG-A may not be
+      able to control the reverse DNS records for SG-A's public IP address.
+      Typical situations include dialup connections and most residential-type broadband Internet access 
+      (ADSL, cable-modem) connections. In these situations, a fully qualified domain
+      name that is under the control of SG-A's administrator may be used
+      when acting as an initiator only.
+      The FQDN ID should be used in phase 1. See <a href="#fqdn">Use of FQDN IDs</a>
+      for more details and restrictions.
+  
+</p>
+<a name="rfc.section.4.4"></a><h4><a name="anchor35">4.4</a>&nbsp;Public key retrieval process</h4>
+
+<p>
+     Upon receipt of a phase 1 SA proposal with either an IPv4 (IPv6) ID or
+     an FQDN ID, an IKE daemon needs to examine local caches and
+     configuration files to determine if this is part of a configured tunnel.
+     If no configured tunnels are found, then the implementation should attempt to retrieve
+     a KEY record from the reverse DNS in the case of an IPv4/IPv6 ID, or 
+     from the forward DNS in the case of FQDN ID.
+  
+</p>
+<p> 
+     It is reasonable that if other non-local sources of policy are used
+     (COPS, LDAP), they be consulted concurrently but some
+     clear ordering of policy be provided. Note that due to variances in
+     latency, implementations must wait for positive or negative replies from all sources
+     of policy before making any decisions.
+  
+</p>
+<a name="rfc.section.4.5"></a><h4><a name="anchor36">4.5</a>&nbsp;Interactions with DNSSEC</h4>
+
+<p>
+     The implementation described (1.98) neither uses DNSSEC directly to
+     explicitly verify the authenticity of zone information, nor uses the NXT
+     records to provide authentication of the absence of a TXT or KEY
+     record. Rather, this implementation uses a trusted path to a DNSSEC
+     capable caching resolver. 
+  
+</p>
+<p> 
+     To distinguish between an authenticated and an unauthenticated DNS
+     resource record, a stub resolver capable of returning DNSSEC
+     information MUST be used.
+  
+</p>
+<a name="rfc.section.4.6"></a><h4><a name="anchor37">4.6</a>&nbsp;Required proposal types</h4>
+
+<a name="rfc.section.4.6.1"></a><h4><a name="phase1id">4.6.1</a>&nbsp;Phase 1 parameters</h4>
+
+<p>
+        Main mode MUST be used.
+      
+</p>
+<p>
+	The initiator MUST offer at least one proposal using some combination
+	of: 3DES, HMAC-MD5 or HMAC-SHA1, DH group 2 or 5. Group 5 SHOULD be
+	proposed first.
+	<a href="#RFC3526">[11]</a>
+</p>
+<p>
+	The initiator MAY offer additional proposals, but the cipher MUST not
+	be weaker than 3DES. The initiator SHOULD limit the number of proposals
+	such that the IKE datagrams do not need to be fragmented.
+      
+</p>
+<p>
+	The responder MUST accept one of the proposals. If any configuration
+	of the responder is required then the responder is not acting in an
+	opportunistic way. 
+      
+</p>
+<p>
+        SG-A SHOULD use an ID_IPV4_ADDR (ID_IPV6_ADDR for IPv6) of the external
+        interface of SG-A for phase 1. (There is an exception, see <a href="#fqdn">Use of FQDN IDs</a>.) The authentication method MUST be RSA public key signatures. 
+        The RSA key for SG-A SHOULD be placed into a DNS KEY record in
+	the reverse space of SG-A (i.e. using in-addr.arpa).
+      
+</p>
+<a name="rfc.section.4.6.2"></a><h4><a name="phase2id">4.6.2</a>&nbsp;Phase 2 parameters</h4>
+
+<p>
+        SG-A MUST propose a tunnel between Alice and Bob, using 3DES-CBC
+        mode, MD5 or SHA1 authentication. Perfect Forward Secrecy MUST be specified.
+      
+</p>
+<p>
+        Tunnel mode MUST be used.
+      
+</p>
+<p>
+        Identities MUST be ID_IPV4_ADDR_SUBNET with the mask being /32.
+      
+</p>
+<p>
+        Authorization for SG-A to act on Alice's behalf is determined by
+        looking for a TXT record in the reverse-map at Alice's address.
+      
+</p>
+<p>
+        Compression SHOULD NOT be mandatory. It may be offered as an option.
+      
+</p>
+<a name="anchor38"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<a name="rfc.section.5"></a><h3>5.&nbsp;DNS issues</h3>
+
+<a name="rfc.section.5.1"></a><h4><a name="KEY">5.1</a>&nbsp;Use of KEY record</h4>
+
+<p>
+    In order to establish their own identities, SG-A and SG-B SHOULD publish
+    their public keys in their reverse DNS via 
+    DNSSEC's KEY record.
+    See section 3 of <a href="#RFC2535">RFC 2535</a>[16].
+  
+</p>
+<p>
+<p>For example:
+</p></font><pre>
+KEY 0x4200 4 1 AQNJjkKlIk9...nYyUkKK8
+</pre><font face="verdana, helvetica, arial, sans-serif" size="2">
+
+<blockquote class="text"><dl>
+<dt>0x4200:</dt>
+<dd> The flag bits, indicating that this key is prohibited
+    for confidentiality use (it authenticates the peer only, a separate
+    Diffie-Hellman exchange is used for
+    confidentiality), and that this key is associated with the non-zone entity
+    whose name is the RR owner name. No other flags are set.
+</dd>
+<dt>4:</dt>
+<dd>This indicates that this key is for use by IPsec.
+</dd>
+<dt>1:</dt>
+<dd>An RSA key is present.
+</dd>
+<dt>AQNJjkKlIk9...nYyUkKK8:</dt>
+<dd>The public key of the host as described in <a href="#RFC3110">[17]</a>.
+</dd>
+</dl></blockquote><p>
+</p>
+<p>Use of several KEY records allows for key rollover. The SIG Payload in
+  IKE phase 1 SHOULD be accepted if the public key given by any KEY RR
+  validates it.
+  
+</p>
+<a name="rfc.section.5.2"></a><h4><a name="TXT">5.2</a>&nbsp;Use of TXT delegation record</h4>
+
+<p>
+Alice publishes a TXT record to provide authorization for SG-A to act on
+Alice's behalf. 
+
+Bob publishes a TXT record to provide authorization for SG-B to act on Bob's
+behalf.  
+
+These records are located in the reverse DNS (in-addr.arpa) for their
+respective IP addresses.  The reverse DNS SHOULD be secured by DNSSEC, when
+it is deployed. DNSSEC is required to defend against active attacks.
+    
+</p>
+<p>
+      If Alice's address is P.Q.R.S, then she can authorize another node to
+      act on her behalf by publishing records at:
+           </p>
+</font><pre>
+S.R.Q.P.in-addr.arpa
+          </pre><font face="verdana, helvetica, arial, sans-serif" size="2">
+<p>
+
+</p>
+<p>
+    The contents of the resource record are expected to be a string that
+    uses the following syntax, as suggested in <a href="#RFC1464">[15]</a>.
+    (Note that the reply to query may include other TXT resource
+    records used by other applications.)
+
+    <br><hr size="1" shade="0">
+<a name="txtformat"></a>
+</p>
+</font><pre>
+X-IPsec-Server(P)=A.B.C.D KEY
+          </pre><font face="verdana, helvetica, arial, sans-serif" size="2">
+<p>
+<table border="0" cellpadding="0" cellspacing="2" align="center"><tr><td align="center"><font face="monaco, MS Sans Serif" size="1"><b>&nbsp;Format of reverse delegation record&nbsp;</b></font><br></td></tr></table><hr size="1" shade="0">
+
+</p>
+<blockquote class="text"><dl>
+<dt>P:</dt>
+<dd> Specifies a precedence for this record.  This is
+      similar to MX record preferences.  Lower numbers have stronger
+      preference. 
+      
+</dd>
+<dt>A.B.C.D:</dt>
+<dd> Specifies the IP address of the Security Gateway
+      for this client machine.
+      
+</dd>
+<dt>KEY:</dt>
+<dd> Is the encoded RSA Public key of the Security
+      Gateway. The key is provided here to avoid a second DNS lookup. If this
+      field is absent, then a KEY resource record should be looked up in the
+      reverse-map of A.B.C.D. The key is transmitted in base64 format.
+      
+</dd>
+</dl></blockquote><p>
+<p>
+  	The pieces of the record are separated by any whitespace
+	(space, tab, newline, carriage return). An ASCII space SHOULD
+	be used.
+    
+</p>
+<p>
+	In the case where Alice is located at a public address behind a 
+	security gateway that has no fixed address (or no control over its
+	reverse-map), then Alice may delegate to a public key by domain name.
+
+    <br><hr size="1" shade="0">
+<a name="txtfqdnformat"></a>
+</p>
+</font><pre>
+X-IPsec-Server(P)=@FQDN KEY
+          </pre><font face="verdana, helvetica, arial, sans-serif" size="2">
+<p>
+<table border="0" cellpadding="0" cellspacing="2" align="center"><tr><td align="center"><font face="monaco, MS Sans Serif" size="1"><b>&nbsp;Format of reverse delegation record (FQDN version)&nbsp;</b></font><br></td></tr></table><hr size="1" shade="0">
+
+</p>
+<blockquote class="text"><dl>
+<dt>P:</dt>
+<dd> Is as above.
+      
+</dd>
+<dt>FQDN:</dt>
+<dd> Specifies the FQDN that the Security Gateway
+      will identify itself with. 
+      
+</dd>
+<dt>KEY:</dt>
+<dd> Is the encoded RSA Public key of the Security
+      Gateway. 
+</dd>
+</dl></blockquote><p>
+<p>
+	If there is more than one such TXT record with strongest (lowest
+	numbered) precedence, one Security Gateway is picked arbitrarily from
+	those specified in the strongest-preference records. 
+    
+</p>
+<a name="rfc.section.5.2.1"></a><h4><a name="anchor39">5.2.1</a>&nbsp;Long TXT records</h4>
+
+<p>
+  When packed into transport format, TXT records which are longer than 255
+  characters are divided into smaller &lt;character-strings&gt;.
+  (See <a href="#RFC1035">[13]</a> section 3.3 and 3.3.14.) These MUST
+  be reassembled into a single string for processing.
+  Whitespace characters in the base64 encoding are to be ignored.
+  
+</p>
+<a name="rfc.section.5.2.2"></a><h4><a name="anchor40">5.2.2</a>&nbsp;Choice of TXT record</h4>
+
+<p>
+	It has been suggested to use the KEY, OPT, CERT, or KX records
+	instead of a TXT record. None is satisfactory.
+  
+</p>
+<p> The KEY RR has a protocol field which could be used to indicate a new protocol, 
+and an algorithm field which could be used to
+        indicate different contents in the key data. However, the KEY record
+	is clearly not intended for storing what are really authorizations,
+	it is just for identities. Other uses have been discouraged.
+  
+</p>
+<p> OPT resource records, as defined in <a href="#RFC2671">[14]</a> are not 
+  intended to be used for storage of information. They are not to be loaded, 
+	cached or forwarded.  They are, therefore, inappropriate for use here.
+  
+</p>
+<p>
+    CERT records <a href="#RFC2538">[18]</a> can encode almost any set of
+    information. A custom type code could be used permitting any suitable
+    encoding to be stored, not just X.509.  According to
+    the RFC, the certificate RRs are to be signed internally which may add undesirable 
+and unnecessary bulk. Larger DNS records may require TCP instead of UDP transfers.
+  
+</p>
+<p>
+    At the time of protocol design, the CERT RR was not widely deployed and
+    could not be counted upon. Use of CERT records will be investigated,
+    and may be proposed in a future revision of this document.
+  
+</p>
+<p>
+    KX records are ideally suited for use instead of TXT records, but had not been deployed at
+    the time of implementation.
+
+</p>
+<a name="rfc.section.5.3"></a><h4><a name="fqdn">5.3</a>&nbsp;Use of FQDN IDs</h4>
+
+<p>
+      Unfortunately, not every administrator has control over the contents
+      of the reverse-map.  Where the initiator (SG-A) has no suitable reverse-map, the
+      authorization record present in the reverse-map of Alice may refer to a
+      FQDN instead of an IP address.
+    
+</p>
+<p>
+      In this case, the client's TXT record gives the fully qualified domain
+      name (FQDN) in place of its security gateway's IP address. 
+      The initiator should use the ID_FQDN ID-payload in phase 1.
+      A forward lookup for a KEY record on the FQDN must yield the
+      initiator's public key. 
+    
+</p>
+<p>
+      This method can also be used when the external address of SG-A is
+      dynamic. 
+    
+</p>
+<p>
+      If SG-A is acting on behalf of Alice, then Alice must still delegate
+      authority for SG-A to do so in her reverse-map. When Alice and SG-A
+      are one and the same (i.e. Alice is acting as an end-node) then there
+      is no need for this when initiating only. 
+</p>
+<p>However, Alice must still delegate to  herself if she wishes others to
+       initiate OE to her.  See <a href="#txtfqdnformat">Format of reverse delegation record (FQDN version)</a>.
+    
+</p>
+<a name="rfc.section.5.4"></a><h4><a name="anchor41">5.4</a>&nbsp;Key roll-over</h4>
+
+<p>
+Good cryptographic hygiene says that one should replace public/private key pairs
+periodically. Some administrators may wish to do this as often as daily. Typical DNS
+propagation delays are determined by the SOA Resource Record MINIMUM
+parameter, which controls how long DNS replies may be cached. For reasonable
+operation of DNS servers, administrators usually want this value to be at least several 
+hours, sometimes as a long as a day. This presents a problem - a new key MUST
+not be used prior to it propagating through DNS.
+
+</p>
+<p>
+This problem is dealt with by having the Security Gateway generate a new
+public/private key pair at least MINIMUM seconds in advance of using it. It
+then adds this key to the DNS (both as a second KEY record and in additional TXT
+delegation records) at key generation time. Note: only one key is allowed in
+each TXT record.
+
+</p>
+<p>
+When authenticating, all gateways MUST have available all public keys 
+that are found in DNS for this entity. This permits the authenticating end
+to check both the key for "today" and the key for "tomorrow". Note that it is 
+the end which is creating the signature (possesses the private key) that
+determines which key is to be used.
+
+</p>
+<a name="anchor42"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<a name="rfc.section.6"></a><h3>6.&nbsp;Network address translation interaction</h3>
+
+<p>
+     There are no fundamentally new issues for implementing opportunistic encryption
+     in the presence of network address translation. Rather there are 
+     only the regular IPsec issues with NAT traversal.
+  
+</p>
+<p>
+     There are several situations to consider for NAT.
+  
+</p>
+<a name="rfc.section.6.1"></a><h4><a name="anchor43">6.1</a>&nbsp;Co-located NAT/NAPT</h4>
+
+<p>
+       If SG-A is also performing network address translation on
+       behalf of Alice, then the packet should be translated prior to
+       being subjected to opportunistic encryption. This is in contrast to
+       typically configured tunnels which often exist to bridge islands of 
+       private network address space. SG-A will use the translated source
+       address for phase 2, and so SG-B will look up that address to
+       confirm SG-A's authorization. 
+    
+</p>
+<p> In the case of NAT (1:1), the address space into which the
+        translation is done MUST be globally unique, and control over the
+	reverse-map is assumed.
+        Placing of TXT records is possible.
+    
+</p>
+<p> In the case of NAPT (m:1), the address will be SG-A. The ability to get
+        KEY and TXT records in place will again depend upon whether or not
+	there is administrative control over the reverse-map. This is
+	identical to situations involving a single host acting on behalf of
+	itself. 
+
+	FQDN style can be used to get around a lack of a reverse-map for
+	initiators only.
+    
+</p>
+<a name="rfc.section.6.2"></a><h4><a name="anchor44">6.2</a>&nbsp;SG-A behind NAT/NAPT</h4>
+
+<p>
+       If there is a NAT or NAPT between SG-A and SG-B, then normal IPsec
+       NAT traversal rules apply. In addition to the transport problem
+       which may be solved by other mechanisms, there
+       is the issue of what phase 1 and phase 2 IDs to use. While FQDN could
+       be used during phase 1 for SG-A, there is no appropriate ID for phase 2
+	that permits SG-B to determine that SG-A is in fact authorized to speak for Alice. 
+    
+</p>
+<a name="rfc.section.6.3"></a><h4><a name="anchor45">6.3</a>&nbsp;Bob is behind a NAT/NAPT</h4>
+
+<p>
+       If Bob is behind a NAT (perhaps SG-B), then there is, in fact, no way for
+       Alice to address a packet to Bob. Not only is opportunistic encryption
+       impossible, but it is also impossible for Alice to initiate any
+       communication to Bob. It may be possible for Bob to initiate in such
+       a situation. This creates an asymmetry, but this is common for 
+       NAPT.
+    
+</p>
+<a name="anchor46"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<a name="rfc.section.7"></a><h3>7.&nbsp;Host implementations</h3>
+
+<p>
+  When Alice and SG-A are components of the same system, they are
+  considered to be a host implementation. The packet sequence scenario remains unchanged.
+
+</p>
+<p>
+  Components marked Alice are the upper layers (TCP, UDP, the
+  application), and SG-A is the IP layer.
+
+</p>
+<p>
+  Note that tunnel mode is still required. 
+
+</p>
+<p>
+  As Alice and SG-A are acting on behalf of themselves, no TXT based delegation
+  record is necessary for Alice to initiate. She can rely on FQDN in a
+  forward map. This is particularly attractive to mobile nodes such as 
+  notebook computers at conferences.
+  To respond, Alice/SG-A will still need an entry in Alice's reverse-map.
+
+</p>
+<a name="anchor47"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<a name="rfc.section.8"></a><h3>8.&nbsp;Multi-homing</h3>
+
+<p> 
+If there are multiple paths between Alice and Bob (as illustrated in
+the diagram with SG-D), then additional DNS records are required to establish
+authorization. 
+
+</p>
+<p>
+In <a href="#networkdiagram">Reference Network Diagram</a>, Alice has two ways to
+exit her network: SG-A and SG-D. Previously SG-D has been ignored. Postulate
+that there are routers between Alice and her set of security gateways
+(denoted by the + signs and the marking of an autonomous system number for
+Alice's network). Datagrams may, therefore, travel to either SG-A or SG-D en
+route to Bob.
+
+</p>
+<p>
+As long as all network connections are in good order, it does not matter how
+datagrams exit Alice's network. When they reach either security gateway, the
+security gateway will find the TXT delegation record in Bob's reverse-map,
+and establish an SA with SG-B. 
+
+</p>
+<p>
+SG-B has no problem establishing that either of SG-A or SG-D may speak for
+Alice, because Alice has published two equally weighted TXT delegation records:
+    <br><hr size="1" shade="0">
+<a name="txtmultiexample"></a>
+</p>
+</font><pre>
+X-IPsec-Server(10)=192.1.1.5 AQMM...3s1Q==
+X-IPsec-Server(10)=192.1.1.6 AAJN...j8r9==
+          </pre><font face="verdana, helvetica, arial, sans-serif" size="2">
+<p>
+<table border="0" cellpadding="0" cellspacing="2" align="center"><tr><td align="center"><font face="monaco, MS Sans Serif" size="1"><b>&nbsp;Multiple gateway delegation example for Alice&nbsp;</b></font><br></td></tr></table><hr size="1" shade="0">
+
+</p>
+<p>
+Alice's routers can now do any kind of load sharing needed. Both SG-A and SG-D send datagrams addressed to Bob through
+their tunnel to SG-B. 
+
+</p>
+<p>
+Alice's use of non-equal weight delegation records to show preference of one gateway over another, has relevance only when SG-B 
+is initiating to Alice. 
+
+</p>
+<p>
+If the precedences are the same, then SG-B has a more difficult time. It
+must decide which of the two tunnels to use. SG-B has no information about
+which link is less loaded, nor which security gateway has more cryptographic
+resources available. SG-B, in fact, has no knowledge of whether both gateways
+are even reachable.  
+
+</p>
+<p>
+The Public Internet's default-free zone may well know a good route to Alice,
+but the datagrams that SG-B creates must be addressed to either SG-A or SG-D;
+they can not be addressed to Alice directly.
+
+</p>
+<p>
+SG-B may make a number of choices:
+
+<ol class="text">
+<li>It can ignore the problem and round robin among the tunnels. This
+      causes losses during times when one or the other security gateway is
+      unreachable. If this worries Alice, she can change the weights in her
+      TXT delegation records.
+</li>
+<li>It can send to the gateway from which it most recently received datagrams. 
+      This assumes that routing and reachability are symmetrical.
+</li>
+<li>It can listen to BGP information from the Internet to decide which
+      system is currently up. This is clearly much more complicated, but if SG-B is already participating
+      in the BGP peering system to announce Bob, the results data may already
+      be available to it. 
+</li>
+<li>It can refuse to negotiate the second tunnel. (It is unclear whether or
+not this is even an option.)
+</li>
+<li>It can silently replace the outgoing portion of the first tunnel with the
+second one while still retaining the incoming portions of both. SG-B can,
+thus, accept datagrams from either SG-A or SG-D, but
+send only to the gateway that most recently re-keyed with it.
+</li>
+</ol><p>
+</p>
+<p>
+Local policy determines which choice SG-B makes. Note that even if SG-B has perfect
+knowledge about the reachability of SG-A and SG-D, Alice may not be reachable
+from either of these security gateways because of internal reachability
+issues. 
+
+</p>
+<p>
+FreeS/WAN implements option 5.  Implementing a different option is
+being considered. The multi-homing aspects of OE are not well developed and may
+be the subject of a future document.
+
+</p>
+<a name="anchor48"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<a name="rfc.section.9"></a><h3>9.&nbsp;Failure modes</h3>
+
+<a name="rfc.section.9.1"></a><h4><a name="anchor49">9.1</a>&nbsp;DNS failures</h4>
+
+<p>
+  If a DNS server fails to respond, local policy decides
+  whether or not to permit communication in the clear as embodied in
+  the connection classes in <a href="#initclasses">Keying state machine - initiator</a>.
+  It is easy to mount a denial of service attack on the DNS server
+  responsible for a particular network's reverse-map.
+  Such an attack may cause all communication with that network to go in
+  the clear if the policy is permissive, or fail completely 
+  if the policy is paranoid. Please note that this is an active attack.
+  
+</p>
+<p>
+  There are still many networks
+  that do not have properly configured reverse-maps. Further, if the policy is not to communicate,
+  the above denial of service attack isolates the target network. Therefore, the decision of whether 
+or not to permit communication in the clear MUST be a matter of local policy.
+  
+</p>
+<a name="rfc.section.9.2"></a><h4><a name="anchor50">9.2</a>&nbsp;DNS configured, IKE failures</h4>
+
+<p>
+  DNS records claim that opportunistic encryption should
+  occur, but the target gateway either does not respond on port 500, or
+  refuses the proposal. This may be because of a crash or reboot, a
+  faulty configuration, or a firewall filtering port 500.  
+  
+</p>
+<p>
+  The receipt of ICMP port, host or network unreachable
+  messages indicates a potential problem, but MUST NOT cause communication
+  to fail 
+  immediately. ICMP messages are easily forged by attackers. If such a
+  forgery caused immediate failure, then an active attacker could easily
+  prevent any 
+  encryption from ever occurring, possibly preventing all communication.
+  
+</p>
+<p>
+  In these situations a clear log should be produced
+  and local policy should dictate if communication is then
+  permitted in the clear.
+  
+</p>
+<a name="rfc.section.9.3"></a><h4><a name="anchor51">9.3</a>&nbsp;System reboots</h4>
+
+<p>
+Tunnels sometimes go down because the remote end crashes,
+disconnects, or has a network link break.  In general there is no
+notification of this.  Even in the event of a crash and successful reboot, 
+other SGs don't hear about it unless the rebooted SG has specific 
+reason to talk to them immediately.  Over-quick response to temporary 
+network outages is undesirable.  Note that a tunnel can be torn
+down and then re-established without any effect visible to the user
+except a pause in traffic. On the other hand, if one end reboots,
+the other end can't get datagrams to it at all (except via
+IKE) until the situation is noticed.  So a bias toward quick
+response is appropriate even at the cost of occasional
+false alarms.
+
+</p>
+<p>
+A mechanism for recovery after reboot is a topic of current research and is not specified in this
+document.
+
+</p>
+<p>
+A deliberate shutdown should include an attempt, using deletes, to notify all other SGs
+currently connected by phase 1 SAs that communication is
+about to fail.  Again, a remote SG will assume this is a teardown.  Attempts by the
+remote SGs to negotiate new tunnels as replacements should be ignored. When possible, 
+SGs should attempt to preserve information about currently-connected SGs in non-volatile storage, so
+that after a crash, an Initial-Contact can be sent to previous partners to
+indicate loss of all previously established connections.
+
+</p>
+<a name="anchor52"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<a name="rfc.section.10"></a><h3>10.&nbsp;Unresolved issues</h3>
+
+<a name="rfc.section.10.1"></a><h4><a name="anchor53">10.1</a>&nbsp;Control of reverse DNS</h4>
+
+<p>
+  The method of obtaining information by reverse DNS lookup causes
+  problems for people who cannot control their reverse DNS
+  bindings. This is an unresolved problem in this version, and is out
+  of scope.
+  
+</p>
+<a name="anchor54"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<a name="rfc.section.11"></a><h3>11.&nbsp;Examples</h3>
+
+<a name="rfc.section.11.1"></a><h4><a name="anchor55">11.1</a>&nbsp;Clear-text usage (permit policy)</h4>
+
+<p>
+Two example scenarios follow. In the first example GW-A
+(Gateway A) and GW-B (Gateway B) have always-clear-text policies, and in the second example they have an OE
+policy.
+
+</p><br><hr size="1" shade="0">
+<a name="regulartiming"></a>
+</font><pre>
+  Alice         SG-A       DNS       SG-B           Bob
+   (1)
+    ------(2)-------------->
+    &lt;-----(3)---------------
+   (4)----(5)----->
+                   ----------(6)------>
+                                       ------(7)----->
+                                      &lt;------(8)------
+                   &lt;----------(9)------
+    &lt;----(10)-----
+   (11)----------->
+                   ----------(12)----->
+                                       -------------->
+                                      &lt;---------------
+                   &lt;-------------------
+    &lt;-------------
+          </pre><font face="verdana, helvetica, arial, sans-serif" size="2">
+<table border="0" cellpadding="0" cellspacing="2" align="center"><tr><td align="center"><font face="monaco, MS Sans Serif" size="1"><b>&nbsp;Timing of regular transaction&nbsp;</b></font><br></td></tr></table><hr size="1" shade="0">
+
+<p>
+Alice wants to communicate with Bob. Perhaps she wants to retrieve a
+web page from Bob's web server. In the absence of opportunistic
+encryptors, the following events occur: 
+
+<blockquote class="text"><dl>
+<dt>(1)</dt>
+<dd>Human or application 'clicks' with a name.
+</dd>
+<dt>(2)</dt>
+<dd>Application looks up name in DNS to get IP address.
+</dd>
+<dt>(3)</dt>
+<dd>Resolver returns A record to application.
+</dd>
+<dt>(4)</dt>
+<dd>Application starts a TCP session or UDP session and OS sends datagram.
+</dd>
+<dt>(5)</dt>
+<dd>Datagram is seen at first gateway from Alice (SG-A). (SG-A
+makes a transition through Empty connection to always-clear connection and
+instantiates a pass-through policy at the forwarding plane.)
+</dd>
+<dt>(6)</dt>
+<dd>Datagram is seen at last gateway before Bob (SG-B).
+</dd>
+<dt>(7)</dt>
+<dd>First datagram from Alice is seen by Bob.
+</dd>
+<dt>(8)</dt>
+<dd>First return datagram is sent by Bob.
+</dd>
+<dt>(9)</dt>
+<dd>Datagram is seen at Bob's gateway. (SG-B makes a transition through
+Empty connection to always-clear connection and instantiates a pass-through
+policy at the forwarding plane.)
+</dd>
+<dt>(10)</dt>
+<dd>Datagram is seen at Alice's gateway.
+</dd>
+<dt>(11)</dt>
+<dd>OS hands datagram to application. Alice sends another datagram.
+</dd>
+<dt>(12)</dt>
+<dd>A second datagram traverses the Internet.
+</dd>
+</dl></blockquote><p>
+</p>
+<a name="rfc.section.11.2"></a><h4><a name="anchor56">11.2</a>&nbsp;Opportunistic encryption</h4>
+
+<p>
+In the presence of properly configured opportunistic encryptors, the
+event list is extended.
+
+<br><hr size="1" shade="0">
+<a name="opportunistictiming"></a>
+</p>
+</font><pre>
+  Alice          SG-A      DNS       SG-B           Bob
+   (1)
+    ------(2)-------------->
+    &lt;-----(3)---------------
+   (4)----(5)----->+
+                  ----(5B)->
+                  &lt;---(5C)--
+                  ~~~~~~~~~~~~~(5D)~~~>
+                  &lt;~~~~~~~~~~~~(5E1)~~~
+                  ~~~~~~~~~~~~~(5E2)~~>
+                  &lt;~~~~~~~~~~~~(5E3)~~~
+                  #############(5E4)##>
+                  &lt;############(5E5)###
+                           &lt;----(5F1)--
+                           -----(5F2)->
+                  #############(5G1)##>
+                           &lt;----(5H1)--
+                           -----(5H2)->
+                  &lt;############(5G2)###
+                  #############(5G3)##>
+                   ============(6)====>
+		                       ------(7)----->
+                                      &lt;------(8)------
+                  &lt;==========(9)======
+    &lt;-----(10)----
+   (11)----------->
+                   ==========(12)=====>
+                                       -------------->
+                                      &lt;---------------
+                   &lt;===================
+    &lt;-------------
+          </pre><font face="verdana, helvetica, arial, sans-serif" size="2">
+<p>
+<table border="0" cellpadding="0" cellspacing="2" align="center"><tr><td align="center"><font face="monaco, MS Sans Serif" size="1"><b>&nbsp;Timing of opportunistic encryption transaction&nbsp;</b></font><br></td></tr></table><hr size="1" shade="0">
+
+<blockquote class="text"><dl>
+<dt>(1)</dt>
+<dd>Human or application clicks with a name.
+</dd>
+<dt>(2)</dt>
+<dd>Application initiates DNS mapping.
+</dd>
+<dt>(3)</dt>
+<dd>Resolver returns A record to application.
+</dd>
+<dt>(4)</dt>
+<dd>Application starts a TCP session or UDP.
+</dd>
+<dt>(5)</dt>
+<dd>SG-A (host or SG) sees datagram to target, and buffers it.
+</dd>
+<dt>(5B)</dt>
+<dd>SG-A asks DNS for TXT record.
+</dd>
+<dt>(5C)</dt>
+<dd>DNS returns TXT record(s).
+</dd>
+<dt>(5D)</dt>
+<dd>Initial IKE Main Mode Packet goes out.
+</dd>
+<dt>(5E)</dt>
+<dd>IKE ISAKMP phase 1 succeeds.
+</dd>
+<dt>(5F)</dt>
+<dd>SG-B asks DNS for TXT record to prove SG-A is an agent for Alice.
+</dd>
+<dt>(5G)</dt>
+<dd>IKE phase 2 negotiation.
+</dd>
+<dt>(5H)</dt>
+<dd>DNS lookup by responder (SG-B).
+</dd>
+<dt>(6)</dt>
+<dd>Buffered datagram is sent by SG-A.
+</dd>
+<dt>(7)</dt>
+<dd>Datagram is received by SG-B, decrypted, and sent to Bob.
+</dd>
+<dt>(8)</dt>
+<dd>Bob replies, and datagram is seen by SG-B.
+</dd>
+<dt>(9)</dt>
+<dd>SG-B already has tunnel up with SG-A, and uses it.
+</dd>
+<dt>(10)</dt>
+<dd>SG-A decrypts datagram and gives it to Alice.
+</dd>
+<dt>(11)</dt>
+<dd>Alice receives datagram. Sends new packet to Bob.
+</dd>
+<dt>(12)</dt>
+<dd>SG-A gets second datagram, sees that tunnel is up, and uses it.
+</dd>
+</dl></blockquote><p>
+</p>
+<p>
+  For the purposes of this section, we will describe only the changes that
+  occur between <a href="#regulartiming">Timing of regular transaction</a> and
+  <a href="#opportunistictiming">Timing of opportunistic encryption transaction</a>. This corresponds to time points 5, 6, 7, 9 and 10 on the list above. 
+  
+</p>
+<a name="rfc.section.11.2.1"></a><h4><a name="anchor57">11.2.1</a>&nbsp;(5) IPsec datagram interception</h4>
+
+<p>
+    At point (5), SG-A intercepts the datagram because this source/destination pair lacks a policy 
+(the non-existent policy state). SG-A creates a hold policy, and buffers the datagram. SG-A requests keys from the keying daemon. 
+    
+</p>
+<a name="rfc.section.11.2.2"></a><h4><a name="anchor58">11.2.2</a>&nbsp;(5B) DNS lookup for TXT record</h4>
+
+<p>
+    SG-A's IKE daemon, having looked up the source/destination pair in the connection
+    class list, creates a new Potential OE connection instance. SG-A starts DNS
+    queries.
+    
+</p>
+<a name="rfc.section.11.2.3"></a><h4><a name="anchor59">11.2.3</a>&nbsp;(5C) DNS returns TXT record(s)</h4>
+
+<p>
+  DNS returns properly formed TXT delegation records, and SG-A's IKE daemon
+  causes this instance to make a transition from Potential OE connection to Pending OE
+  connection.
+  
+</p>
+<p>
+      Using the example above, the returned record might contain:
+
+    <br><hr size="1" shade="0">
+<a name="txtexample"></a>
+</p>
+</font><pre>
+X-IPsec-Server(10)=192.1.1.5 AQMM...3s1Q==
+          </pre><font face="verdana, helvetica, arial, sans-serif" size="2">
+<p>
+<table border="0" cellpadding="0" cellspacing="2" align="center"><tr><td align="center"><font face="monaco, MS Sans Serif" size="1"><b>&nbsp;Example of reverse delegation record for Bob&nbsp;</b></font><br></td></tr></table><hr size="1" shade="0">
+
+    with SG-B's IP address and public key listed.
+    
+</p>
+<a name="rfc.section.11.2.4"></a><h4><a name="anchor60">11.2.4</a>&nbsp;(5D) Initial IKE main mode packet goes out</h4>
+
+<p>Upon entering Pending OE connection, SG-A sends the initial ISAKMP
+  message with proposals. See <a href="#phase1id">Phase 1 parameters</a>.
+  
+</p>
+<a name="rfc.section.11.2.5"></a><h4><a name="anchor61">11.2.5</a>&nbsp;(5E1) Message 2 of phase 1 exchange</h4>
+
+<p>
+  SG-B receives the message. A new connection instance is created in the
+  unauthenticated OE peer state.
+  
+</p>
+<a name="rfc.section.11.2.6"></a><h4><a name="anchor62">11.2.6</a>&nbsp;(5E2) Message 3 of phase 1 exchange</h4>
+
+<p>
+  SG-A sends a Diffie-Hellman exponent. This is an internal state of the
+  keying daemon.
+  
+</p>
+<a name="rfc.section.11.2.7"></a><h4><a name="anchor63">11.2.7</a>&nbsp;(5E3) Message 4 of phase 1 exchange</h4>
+
+<p>
+  SG-B responds with a Diffie-Hellman exponent. This is an internal state of the
+  keying protocol.
+  
+</p>
+<a name="rfc.section.11.2.8"></a><h4><a name="anchor64">11.2.8</a>&nbsp;(5E4) Message 5 of phase 1 exchange</h4>
+
+<p>
+  SG-A uses the phase 1 SA to send its identity under encryption. 
+  The choice of identity is discussed in <a href="#phase1id">Phase 1 parameters</a>.
+  This is an internal state of the keying protocol.
+  
+</p>
+<a name="rfc.section.11.2.9"></a><h4><a name="anchor65">11.2.9</a>&nbsp;(5F1) Responder lookup of initiator key</h4>
+
+<p>
+  SG-B asks DNS for the public key of the initiator. 
+  DNS looks for a KEY record by IP address in the reverse-map.
+  That is, a KEY resource record is queried for 4.1.1.192.in-addr.arpa
+  (recall that SG-A's external address is 192.1.1.4).
+  SG-B uses the resulting public key to authenticate the initiator. See <a href="#KEY">Use of KEY record</a> for further details. 
+  
+</p>
+<a name="rfc.section.11.2.10"></a><h4><a name="anchor66">11.2.10</a>&nbsp;(5F2) DNS replies with public key of initiator</h4>
+
+<p>
+Upon successfully authenticating the peer, the connection instance makes a
+transition to authenticated OE peer on SG-B.
+
+</p>
+<p>
+The format of the TXT record returned is described in
+<a href="#TXT">Use of TXT delegation record</a>. 
+
+</p>
+<a name="rfc.section.11.2.11"></a><h4><a name="anchor67">11.2.11</a>&nbsp;(5E5) Responder replies with ID and authentication</h4>
+
+<p>
+    SG-B sends its ID along with authentication material. This is an internal
+    state for the keying protocol.
+  
+</p>
+<a name="rfc.section.11.2.12"></a><h4><a name="anchor68">11.2.12</a>&nbsp;(5G) IKE phase 2</h4>
+
+<a name="rfc.section.11.2.12.1"></a><h4><a name="anchor69">11.2.12.1</a>&nbsp;(5G1) Initiator proposes tunnel</h4>
+
+<p>
+    Having established mutually agreeable authentications (via KEY) and
+    authorizations (via TXT), SG-A proposes to create an IPsec tunnel for
+    datagrams transiting from Alice to Bob. This tunnel is established only for 
+    the Alice/Bob combination, not for any subnets that may be behind SG-A and SG-B.
+    
+</p>
+<a name="rfc.section.11.2.12.2"></a><h4><a name="anchor70">11.2.12.2</a>&nbsp;(5H1) Responder determines initiator's authority</h4>
+
+<p>
+    While the identity of SG-A has been established, its authority to
+    speak for Alice has not yet been confirmed. SG-B does a reverse
+    lookup on Alice's address for a TXT record. 
+    
+</p>
+<p>Upon receiving this specific proposal, SG-B's connection instance
+    makes a transition into the potential OE connection state. SG-B may already have an
+    instance, and the check is made as described above.
+</p>
+<a name="rfc.section.11.2.12.3"></a><h4><a name="anchor71">11.2.12.3</a>&nbsp;(5H2) DNS replies with TXT record(s)</h4>
+
+<p>
+      The returned key and IP address should match that of SG-A.
+    
+</p>
+<a name="rfc.section.11.2.12.4"></a><h4><a name="anchor72">11.2.12.4</a>&nbsp;(5G2) Responder agrees to proposal</h4>
+
+<p>
+    Should additional communication occur between, for instance, Dave and Bob using
+    SG-A and SG-B, a new tunnel (phase 2 SA) would be established. The phase 1 SA
+    may be reusable.
+    
+</p>
+<p>SG-A, having successfully keyed the tunnel, now makes a transition from
+    Pending OE connection to Keyed OE connection.
+    
+</p>
+<p>The responder MUST setup the inbound IPsec SAs before sending its reply.
+</p>
+<a name="rfc.section.11.2.12.5"></a><h4><a name="anchor73">11.2.12.5</a>&nbsp;(5G3) Final acknowledgment from initiator</h4>
+
+<p>
+    The initiator agrees with the responder's choice and sets up the tunnel.
+    The initiator sets up the inbound and outbound IPsec SAs.
+    
+</p>
+<p>
+    The proper authorization returned with keys prompts SG-B to make a transition
+    to the keyed OE connection state. 
+    
+</p>
+<p>Upon receipt of this message, the responder may now setup the outbound
+    IPsec SAs.
+</p>
+<a name="rfc.section.11.2.13"></a><h4><a name="anchor74">11.2.13</a>&nbsp;(6) IPsec succeeds, and sets up tunnel for communication between Alice and Bob</h4>
+
+<p>
+  SG-A sends the datagram saved at step (5) through the newly created
+  tunnel to SG-B, where it gets decrypted and forwarded. 
+  Bob receives it at (7) and replies at (8). 
+  
+</p>
+<a name="rfc.section.11.2.14"></a><h4><a name="anchor75">11.2.14</a>&nbsp;(9) SG-B already has tunnel up with G1 and uses it</h4>
+
+<p>
+  At (9), SG-B has already established an SPD entry mapping Bob->Alice via a
+  tunnel, so this tunnel is simply applied. The datagram is encrypted to SG-A,
+  decrypted by SG-A and passed to Alice at (10).
+  
+</p>
+<a name="securityconsiderations"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<a name="rfc.section.12"></a><h3>12.&nbsp;Security considerations</h3>
+
+<a name="rfc.section.12.1"></a><h4><a name="anchor76">12.1</a>&nbsp;Configured vs opportunistic tunnels</h4>
+
+<p>
+    Configured tunnels are those which are setup using bilateral mechanisms: exchanging 
+public keys (raw RSA, DSA, PKIX), pre-shared secrets, or by referencing keys that
+are in known places (distinguished name from LDAP, DNS). These keys are then used to
+configure a specific tunnel. 
+
+</p>
+<p>
+A pre-configured tunnel may be on all the time, or may be keyed only when needed. 
+The end points of the tunnel are not necessarily static: many mobile
+applications (road warrior) are considered to be configured tunnels. 
+
+</p>
+<p>
+The primary characteristic is that configured tunnels are assigned specific
+security properties. They may be trusted in different ways relating to exceptions to 
+firewall rules, exceptions to NAT processing, and to bandwidth or other quality of service restrictions. 
+
+</p>
+<p>
+Opportunistic tunnels are not inherently trusted in any strong way. They are
+created without prior arrangement. As the two parties are strangers, there
+MUST be no confusion of datagrams that arrive from opportunistic peers and
+those that arrive from configured tunnels. A security gateway MUST take care
+that an opportunistic peer can not impersonate a configured peer.
+
+</p>
+<p>
+Ingress filtering MUST be used to make sure that only datagrams authorized by
+negotiation (and the concomitant authentication and authorization) are
+accepted from a tunnel. This is to prevent one peer from impersonating another. 
+
+</p>
+<p>
+An implementation suggestion is to treat opportunistic tunnel
+datagrams as if they arrive on a logical interface distinct from other
+configured tunnels. As the number of opportunistic tunnels that may be
+created automatically on a system is potentially very high, careful attention 
+to scaling should be taken into account.
+
+</p>
+<p>
+As with any IKE negotiation, opportunistic encryption cannot be secure
+without authentication. Opportunistic encryption relies on DNS for its
+authentication information and, therefore, cannot be fully secure without
+a secure DNS. Without secure DNS, opportunistic encryption can protect against passive
+eavesdropping but not against active man-in-the-middle attacks.
+
+</p>
+<a name="rfc.section.12.2"></a><h4><a name="anchor77">12.2</a>&nbsp;Firewalls versus Opportunistic Tunnels</h4>
+
+<p>
+  Typical usage of per datagram access control lists is to implement various
+kinds of security gateways. These are typically called "firewalls". 
+
+</p>
+<p>
+  Typical usage of a virtual private network (VPN) within a firewall is to
+bypass all or part of the access controls between two networks. Additional
+trust (as outlined in the previous section) is given to datagrams that arrive
+in the VPN.
+
+</p>
+<p> 
+  Datagrams that arrive via opportunistically configured tunnels MUST not be
+trusted. Any security policy that would apply to a datagram arriving in the
+clear SHOULD also be applied to datagrams arriving opportunistically.
+
+</p>
+<a name="rfc.section.12.3"></a><h4><a name="anchor78">12.3</a>&nbsp;Denial of service</h4>
+
+<p>
+  There are several different forms of denial of service that an implementor 
+  should concern themselves with. Most of these problems are shared with
+  security gateways that have large numbers of mobile peers (road warriors). 
+
+</p>
+<p>
+  The design of ISAKMP/IKE, and its use of cookies, defend against many kinds
+  of denial of service. Opportunism changes the assumption that if the phase 1 (ISAKMP) 
+  SA is authenticated, that it was worthwhile creating. Because the gateway will communicate with any machine, it is
+  possible to form phase 1 SAs with any machine on the Internet. 
+
+</p>
+<a name="anchor79"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<a name="rfc.section.13"></a><h3>13.&nbsp;IANA Considerations</h3>
+
+<p>
+    There are no known numbers which IANA will need to manage.
+
+</p>
+<a name="anchor80"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<a name="rfc.section.14"></a><h3>14.&nbsp;Acknowledgments</h3>
+
+<p>
+        Substantive portions of this document are based upon previous work by
+        Henry Spencer.
+
+</p>
+<p>
+	Thanks to Tero Kivinen, Sandy Harris, Wes Hardarker, Robert Moskowitz,
+	Jakob Schlyter, Bill Sommerfeld, John Gilmore and John Denker for their
+	comments and constructive criticism.
+
+</p>
+<p>
+	Sandra Hoffman and Bill Dickie did the detailed proof reading and editing.
+
+</p>
+<a name="rfc.references1"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<h3>Normative references</h3>
+<table width="99%" border="0">
+<tr><td class="author-text" valign="top"><b><a name="OEspec">[1]</a></b></td>
+<td class="author-text"><a href="mailto:hugh@mimosa.com">Redelmeier, D.</a> and <a href="mailto:henry@spsystems.net">H. Spencer</a>, "Opportunistic Encryption", paper http://www.freeswan.org/freeswan_trees/freeswan-1.91/doc/opportunism.spec, May 2001.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC0791">[2]</a></b></td>
+<td class="author-text">Defense Advanced Research Projects Agency (DARPA), Information Processing Techniques Office and University of Southern California (USC)/Information Sciences Institute, "<a href="ftp://ftp.isi.edu/in-notes/rfc791.txt">Internet Protocol</a>", STD 5, RFC 791, September 1981.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC1009">[3]</a></b></td>
+<td class="author-text"><a href="mailto:">Braden, R.</a> and <a href="mailto:">J. Postel</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc1009.txt">Requirements for Internet gateways</a>", RFC 1009, June 1987.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC1984">[4]</a></b></td>
+<td class="author-text">IAB, IESG, <a href="mailto:brian@dxcoms.cern.ch">Carpenter, B.</a> and <a href="mailto:fred@cisco.com">F. Baker</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc1984.txt">IAB and IESG Statement on Cryptographic Technology and the Internet</a>", RFC 1984, August 1996.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC2119">[5]</a></b></td>
+<td class="author-text"><a href="mailto:-">Bradner, S.</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2119.txt">Key words for use in RFCs to Indicate Requirement Levels</a>", BCP 14, RFC 2119, March 1997.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC2367">[6]</a></b></td>
+<td class="author-text"><a href="mailto:danmcd@eng.sun.com">McDonald, D.</a>, <a href="mailto:cmetz@inner.net">Metz, C.</a> and <a href="mailto:phan@itd.nrl.navy.mil">B. Phan</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2367.txt">PF_KEY Key Management API, Version 2</a>", RFC 2367, July 1998.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC2401">[7]</a></b></td>
+<td class="author-text"><a href="mailto:kent@bbn.com">Kent, S.</a> and <a href="mailto:rja@corp.home.net">R. Atkinson</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2401.txt">Security Architecture for the Internet Protocol</a>", RFC 2401, November 1998.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC2407">[8]</a></b></td>
+<td class="author-text"><a href="mailto:ddp@network-alchemy.com">Piper, D.</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2407.txt">The Internet IP Security Domain of Interpretation for ISAKMP</a>", RFC 2407, November 1998.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC2408">[9]</a></b></td>
+<td class="author-text"><a href="mailto:wdm@tycho.ncsc.mil">Maughan, D.</a>, <a href="mailto:mss@tycho.ncsc.mil">Schneider, M.</a> and <a href="er@raba.com">M. Schertler</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2408.txt">Internet Security Association and Key Management Protocol (ISAKMP)</a>", RFC 2408, November 1998.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC2409">[10]</a></b></td>
+<td class="author-text"><a href="mailto:dharkins@cisco.com">Harkins, D.</a> and <a href="mailto:carrel@ipsec.org">D. Carrel</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2409.txt">The Internet Key Exchange (IKE)</a>", RFC 2409, November 1998.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC3526">[11]</a></b></td>
+<td class="author-text"><a href="mailto:kivinen@ssh.fi">Kivinen, T.</a> and <a href="mailto:mrskojo@cc.helsinki.fi">M. Kojo</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc3526.txt">More MODP Diffie-Hellman groups for IKE</a>", RFC 3526, March 2003.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC1034">[12]</a></b></td>
+<td class="author-text">Mockapetris, P., "<a href="ftp://ftp.isi.edu/in-notes/rfc1034.txt">Domain names - concepts and facilities</a>", STD 13, RFC 1034, November 1987.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC1035">[13]</a></b></td>
+<td class="author-text"><a href="mailto:">Mockapetris, P.</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc1035.txt">Domain names - implementation and specification</a>", STD 13, RFC 1035, November 1987.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC2671">[14]</a></b></td>
+<td class="author-text"><a href="mailto:vixie@isc.org">Vixie, P.</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2671.txt">Extension Mechanisms for DNS (EDNS0)</a>", RFC 2671, August 1999.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC1464">[15]</a></b></td>
+<td class="author-text"><a href="mailto:rosenbaum@lkg.dec.com">Rosenbaum, R.</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc1464.txt">Using the Domain Name System To Store Arbitrary String Attributes</a>", RFC 1464, May 1993.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC2535">[16]</a></b></td>
+<td class="author-text"><a href="mailto:dee3@us.ibm.com">Eastlake, D.</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2535.txt">Domain Name System Security Extensions</a>", RFC 2535, March 1999.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC3110">[17]</a></b></td>
+<td class="author-text">Eastlake, D., "<a href="ftp://ftp.isi.edu/in-notes/rfc3110.txt">RSA/SHA-1 SIGs and RSA KEYs in the Domain Name System (DNS)</a>", RFC 3110, May 2001.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC2538">[18]</a></b></td>
+<td class="author-text"><a href="mailto:dee3@us.ibm.com">Eastlake, D.</a> and <a href="mailto:ogud@tislabs.com">O. Gudmundsson</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2538.txt">Storing Certificates in the Domain Name System (DNS)</a>", RFC 2538, March 1999.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC2748">[19]</a></b></td>
+<td class="author-text"><a href="mailto:David.Durham@intel.com">Durham, D.</a>, <a href="mailto:jboyle@Level3.net">Boyle, J.</a>, <a href="mailto:ronc@cisco.com">Cohen, R.</a>, <a href="mailto:herzog@iphighway.com">Herzog, S.</a>, <a href="mailto:rajan@research.att.com">Rajan, R.</a> and <a href="mailto:asastry@cisco.com">A. Sastry</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2748.txt">The COPS (Common Open Policy Service) Protocol</a>", RFC 2748, January 2000.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC2663">[20]</a></b></td>
+<td class="author-text"><a href="mailto:srisuresh@lucent.com">Srisuresh, P.</a> and <a href="mailto:holdrege@lucent.com">M. Holdrege</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2663.txt">IP Network Address Translator (NAT) Terminology and Considerations</a>", RFC 2663, August 1999.</td></tr>
+</table>
+
+<a name="rfc.authors"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<h3>Authors' Addresses</h3>
+<table width="99%" border="0" cellpadding="0" cellspacing="0">
+<tr><td class="author-text">&nbsp;</td>
+<td class="author-text">Michael C. Richardson</td></tr>
+<tr><td class="author-text">&nbsp;</td>
+<td class="author-text">Sandelman Software Works</td></tr>
+<tr><td class="author-text">&nbsp;</td>
+<td class="author-text">470 Dawson Avenue</td></tr>
+<tr><td class="author-text">&nbsp;</td>
+<td class="author-text">Ottawa, ON  K1Z 5V7</td></tr>
+<tr><td class="author-text">&nbsp;</td>
+<td class="author-text">CA</td></tr>
+<tr><td class="author" align="right">EMail:&nbsp;</td>
+<td class="author-text"><a href="mailto:mcr@sandelman.ottawa.on.ca">mcr@sandelman.ottawa.on.ca</a></td></tr>
+<tr><td class="author" align="right">URI:&nbsp;</td>
+<td class="author-text"><a href="http://www.sandelman.ottawa.on.ca/">http://www.sandelman.ottawa.on.ca/</a></td></tr>
+<tr cellpadding="3"><td>&nbsp;</td><td>&nbsp;</td></tr>
+<tr><td class="author-text">&nbsp;</td>
+<td class="author-text">D. Hugh Redelmeier</td></tr>
+<tr><td class="author-text">&nbsp;</td>
+<td class="author-text">Mimosa</td></tr>
+<tr><td class="author-text">&nbsp;</td>
+<td class="author-text">Toronto, ON</td></tr>
+<tr><td class="author-text">&nbsp;</td>
+<td class="author-text">CA</td></tr>
+<tr><td class="author" align="right">EMail:&nbsp;</td>
+<td class="author-text"><a href="mailto:hugh@mimosa.com">hugh@mimosa.com</a></td></tr>
+</table>
+<a name="rfc.copyright"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<h3>Full Copyright Statement</h3>
+<p class='copyright'>
+Copyright (C) The Internet Society (2003). All Rights Reserved.</p>
+<p class='copyright'>
+This document and translations of it may be copied and furnished to
+others, and derivative works that comment on or otherwise explain it
+or assist in its implementation may be prepared, copied, published and
+distributed, in whole or in part, without restriction of any kind,
+provided that the above copyright notice and this paragraph are
+included on all such copies and derivative works. However, this
+document itself may not be modified in any way, such as by removing
+the copyright notice or references to the Internet Society or other
+Internet organizations, except as needed for the purpose of
+developing Internet standards in which case the procedures for
+copyrights defined in the Internet Standards process must be
+followed, or as required to translate it into languages other than
+English.</p>
+<p class='copyright'>
+The limited permissions granted above are perpetual and will not be
+revoked by the Internet Society or its successors or assigns.</p>
+<p class='copyright'>
+This document and the information contained herein is provided on an
+&quot;AS IS&quot; basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
+TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
+BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
+HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
+MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.</p>
+<h3>Acknowledgement</h3>
+<p class='copyright'>
+Funding for the RFC Editor function is currently provided by the
+Internet Society.</p>
+</font></body></html>
diff --git a/doc/src/draft-richardson-ipsec-opportunistic.xml b/doc/src/draft-richardson-ipsec-opportunistic.xml
new file mode 100644
index 000000000..d587df693
--- /dev/null
+++ b/doc/src/draft-richardson-ipsec-opportunistic.xml
@@ -0,0 +1,2519 @@
+<?xml version="1.0"?>
+<!DOCTYPE rfc SYSTEM "rfc2629.dtd">
+<?rfc toc="yes"?>
+<?rfc tocdepth='2' ?>
+
+<rfc ipr="full2026" docName="draft-richardson-ipsec-opportunistic-12.txt">
+
+<front>
+  <area>Security</area>
+  <workgroup>Independent submission</workgroup>
+  <title abbrev="opportunistic">
+     Opportunistic Encryption using The Internet Key Exchange (IKE)
+  </title>
+
+  <author initials="M." surname="Richardson" fullname="Michael C. Richardson">
+    <organization abbrev="SSW">Sandelman Software Works</organization>
+    <address>
+      <postal>   
+        <street>470 Dawson Avenue</street>
+        <city>Ottawa</city>
+        <region>ON</region>
+        <code>K1Z 5V7</code>
+        <country>CA</country>
+      </postal>
+      <email>mcr@sandelman.ottawa.on.ca</email>
+      <uri>http://www.sandelman.ottawa.on.ca/</uri>
+    </address>
+  </author>
+
+  <author initials="D.H." surname="Redelmeier"
+          fullname="D. Hugh Redelmeier">
+    <organization abbrev="Mimosa">Mimosa</organization>
+    <address>
+      <postal>   
+        <city>Toronto</city>
+        <region>ON</region>
+        <country>CA</country>
+      </postal>
+      <email>hugh@mimosa.com</email>
+    </address>
+  </author>
+
+  <date month="June" year="2003"></date>
+
+<abstract>
+  <t>
+This document describes opportunistic encryption (OE) using the Internet Key
+Exchange (IKE) and IPsec.  
+Each system administrator adds new
+resource records to his or her Domain Name System (DNS) to support
+opportunistic encryption. The objective is to allow encryption for secure communication without
+any pre-arrangement specific to the pair of systems involved.
+  </t>
+  <t>
+DNS is used to distribute the public keys of each
+system involved. This is resistant to passive attacks. The use of DNS
+Security (DNSSEC) secures this system against active attackers as well. 
+  </t>
+  <t>
+As a result, the administrative overhead is reduced
+from the square of the number of systems to a linear dependence, and it becomes  
+possible to make secure communication the default even
+when the partner is not known in advance.
+  </t>
+  <t>
+This document is offered up as an Informational RFC.
+  </t>
+</abstract>
+
+</front>
+
+<middle>
+
+<section title="Introduction">
+
+<section title="Motivation">
+
+<t>
+The objective of opportunistic encryption is to allow encryption without
+any pre-arrangement specific to the pair of systems involved. Each
+system administrator adds
+public key information to DNS records to support opportunistic
+encryption and then enables this feature in the nodes' IPsec stack. 
+Once this is done, any two such nodes can communicate securely.
+</t>
+
+<t>
+This document describes opportunistic encryption as designed and
+implemented by the Linux FreeS/WAN project in revisions up and including 2.00.
+Note that 2.01 and beyond implements RFC3445, in a backward compatible way.
+For project information, see http://www.freeswan.org.
+</t>
+
+  <t>
+The Internet Architecture Board (IAB) and Internet Engineering
+Steering Group (IESG) have taken a strong stand that the Internet
+should use powerful encryption to provide security and
+privacy <xref target="RFC1984" />.
+The Linux FreeS/WAN project attempts to provide a practical means to implement this policy. 
+  </t>
+
+  <t>
+The project uses the IPsec, ISAKMP/IKE, DNS and DNSSEC
+protocols because they are
+standardized, widely available and can often be deployed very easily
+without changing hardware or software or retraining users. 
+  </t>
+
+  <t>
+The extensions to support opportunistic encryption are simple.  No
+changes to any on-the-wire formats are needed.  The only changes are to 
+the policy decision making system.  This means that opportunistic
+encryption can be implemented with very minimal changes to an existing 
+IPsec implementation.
+  </t>
+
+  <t>
+Opportunistic encryption creates a "fax effect". The proliferation
+of the fax machine was possible because it did not require that everyone
+buy one overnight. Instead, as each person installed one, the value
+of having one increased - as there were more people that could receive faxes.
+Once opportunistic encryption is installed it
+automatically recognizes 
+other boxes using opportunistic encryption, without any further configuration
+by the network 
+administrator. So, as opportunistic encryption software is installed on more
+boxes, its value 
+as a tool increases.
+</t>
+
+  <t>
+This document describes the infrastructure to permit deployment of
+Opportunistic Encryption.
+</t>
+ 
+  <t>
+The term S/WAN is a trademark of RSA Data Systems, and is used with permission
+by this project.
+  </t>
+
+</section>
+
+<section title="Types of network traffic">
+  <t>
+    To aid in understanding the relationship between security processing and IPsec
+    we divide network traffic into four categories:
+    <list style="hanging">
+      <t hangText="* Deny:"> networks to which traffic is always forbidden.</t>
+      <t hangText="* Permit:"> networks to which traffic in the clear is permitted.</t>
+      <t hangText="* Opportunistic tunnel:"> networks to which traffic is encrypted if possible, but otherwise is in the clear  
+	    or fails depending on the default policy in place.	
+      </t>
+      <t hangText="* Configured tunnel:"> networks to which traffic
+must be encrypted, and traffic in the clear is never permitted.
+A Virtual Private Network (VPN) is a form of configured tunnel.
+</t>
+    </list>      
+  </t>
+
+<t>
+Traditional firewall devices handle the first two categories.
+No authentication is required.  
+The permit policy is currently the default on the Internet. 
+</t>
+
+<t>
+This document describes the third category - opportunistic tunnel, which is
+proposed as the new default for the Internet.
+</t>
+
+<t>
+  Category four, encrypt traffic or drop it, requires authentication of the
+  end points. As the number of end points is typically bounded and is typically
+  under a single authority, arranging for distribution of
+  authentication material, while difficult, does not require any new
+  technology. The mechanism described here provides an additional way to
+  distribute the authentication materials, that of a public key method that does not
+  require deployment of an X.509 based infrastructure.  
+</t>
+<t>
+Current Virtual Private Networks can often be replaced by an "OE paranoid"
+policy as described herein. 
+</t>
+</section>	
+
+<section title="Peer authentication in opportunistic encryption">
+
+  <t>
+  Opportunistic encryption creates tunnels between nodes that
+  are essentially strangers. This is done without any prior bilateral
+  arrangement. 
+  There is, therefore, the difficult question of how one knows to whom one is
+  talking.
+  </t>
+
+  <t>
+  One possible answer is that since no useful
+  authentication can be done, none should be tried. This mode of operation is
+  named "anonymous encryption".  An active man-in-the-middle attack can be
+  used to thwart the privacy of this type of communication. 
+  Without peer authentication, there is no way to prevent this kind of attack.
+  </t>
+
+  <t>
+Although a useful mode, anonymous encryption is not the goal of this
+project. Simpler methods are available that can achieve anonymous
+encryption only, but authentication of the peer is a desireable goal.
+The latter is achieved through key distribution in DNS, leveraging upon
+the authentication of the DNS in DNSSEC.
+</t>
+
+  <t>
+  Peers are, therefore, authenticated with DNSSEC when available. Local policy 
+determines how much trust to extend when DNSSEC is not available.
+  </t>
+
+  <t>
+  However, an essential premise of building private connections with
+  strangers is that datagrams received through opportunistic tunnels
+  are no more special than datagrams that arrive in the clear.
+  Unlike in a VPN, these datagrams should not be given any special
+  exceptions when it comes to auditing, further authentication or
+  firewalling.
+  </t>
+  
+  <t>
+  When initiating outbound opportunistic encryption, local 
+  configuration determines what happens if tunnel setup fails. It may be that
+  the packet goes out in the clear, or it may be dropped.
+  </t>
+
+  </section>
+
+<section title="Use of RFC2119 terms">
+<t>
+   The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
+   SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this
+   document, are to be interpreted as described in <xref target="RFC2119" />
+</t>
+</section>
+
+</section>
+
+<section title="Overview">
+
+  <section title="Reference diagram">
+
+    <figure anchor="networkdiagram" title="Reference Network Diagram">
+	   <preamble>The following network diagram is used in the rest of
+		this document as the canonical diagram:</preamble>
+           <artwork>
+                          [Q]  [R]          
+                           .    .              AS2                 
+  [A]----+----[SG-A].......+....+.......[SG-B]-------[B]
+         |                 ......
+     AS1 |                 ..PI..
+         |                 ......
+  [D]----+----[SG-D].......+....+.......[C] AS3
+             
+
+           </artwork>
+           <postamble></postamble>
+
+       </figure>
+
+    <t>
+    In this diagram, there are four end-nodes: A, B, C and D. 
+    There are three security gateways, SG-A, SG-B, SG-D. A, D, SG-A and
+    SG-D are part 
+    of the same administrative authority, AS1. SG-A and SG-D are on two
+    different exit
+    paths from organization 1. SG-B/B is an independent organization, AS2.
+    Nodes Q and R are nodes on the Internet. PI is the Public
+    Internet ("The Wild").
+    </t>
+
+  </section>
+
+  <section title="Terminology">
+
+  <t>
+  The following terminology is used in this document:
+  </t>
+
+  <list style="hanging">
+    <t hangText="Security gateway (or simply gateway):"> a system that performs IPsec tunnel
+    mode encapsulation/decapsulation. [SG-x] in the diagram.</t>
+    <t hangText="Alice:"> node [A] in the diagram. When an IP address is needed, this is 192.1.0.65.</t>
+    <t hangText="Bob:"> node [B] in the diagram. When an IP address is needed, this is 192.2.0.66.</t>
+    <t hangText="Carol:"> node [C] in the diagram. When an IP address is needed, this is 192.1.1.67.</t>
+    <t hangText="Dave:"> node [D] in the diagram. When an IP address is needed, this is 192.3.0.68.</t>
+    <t hangText="SG-A:"> Alice's security gateway. Internally it is 192.1.0.1, externally it is 192.1.1.4.</t>
+    <t hangText="SG-B:"> Bob's security gateway. Internally it is 192.2.0.1, externally it is 192.1.1.5.</t>
+    <t hangText="SG-D:"> Dave's security gateway. Also Alice's backup security gateway. Internally it is 192.3.0.1, externally it is 192.1.1.6.</t>
+    <t hangText="."> A period represents an untrusted network of unknown
+        type.</t> 
+    <t hangText="Configured tunnel:"> a tunnel that
+		  is directly and deliberately hand configured on participating gateways.
+		  Configured tunnels are typically given a higher level of
+		  trust than opportunistic tunnels.</t> 
+
+    <t hangText="Road warrior tunnel:"> a configured tunnel connecting one
+		  node with a fixed IP address and one node with a variable IP address.
+		  A road warrior (RW) connection must be initiated by the
+		  variable node, since the fixed node cannot know the
+		  current address for the road warrior. </t>
+
+    <t hangText="Anonymous encryption:">
+	the process of encrypting a session without any knowledge of who the
+	other parties are. No authentication of identities is done.</t>
+
+    <t hangText="Opportunistic encryption:">
+	the process of encrypting a session with authenticated knowledge of
+	who the other party is.</t>
+
+    <t hangText="Lifetime:">
+        the period in seconds (bytes or datagrams) for which a security
+	association will remain alive before needing to be re-keyed.</t>
+
+    <t hangText="Lifespan:">
+        the effective time for which a security association remains useful. A
+	security association with a lifespan shorter than its lifetime would
+	be removed when no longer needed. A security association with a
+	lifespan longer than its lifetime would need to be re-keyed one or
+	more times.</t>
+    
+    <t hangText="Phase 1 SA:"> an ISAKMP/IKE security association sometimes
+      referred to as a keying channel.</t>
+
+    <t hangText="Phase 2 SA:"> an IPsec security association.</t>
+
+    <t hangText="Tunnel:"> another term for a set of phase 2 SA (one in each direction).</t>
+
+    <t hangText="NAT:"> Network Address Translation
+    (see <xref target="RFC2663" />).</t>
+
+    <t hangText="NAPT:"> Network Address and Port Translation
+    (see <xref target="RFC2663" />).</t>
+
+    <t hangText="AS:"> an autonomous system </t>
+
+    <t hangText="FQDN:"> Fully-Qualified Domain Name </t>
+
+    <t hangText="Default-free zone:"> 
+    a set of routers that maintain a complete set of routes to
+    all currently reachable destinations. Having such a list, these routers
+    never make use of a default route. A datagram with a destination address
+    not matching any route will be dropped by such a router.
+    </t>
+
+  </list>
+  </section>
+
+<section title="Model of operation">
+
+<t>
+The opportunistic encryption security gateway (OE gateway) is a regular
+gateway node as described in <xref target="RFC0791" /> section 2.4 and  
+<xref target="RFC1009" /> with the additional capabilities described here and
+in <xref target="RFC2401" />.  
+The algorithm described here provides a way to determine, for each datagram,
+whether or not to encrypt and tunnel the datagram. Two important things
+that must be determined are whether or not to encrypt and tunnel and, if
+so, the destination address or name of the tunnel end point which should be used. 
+</t>
+
+<section title="Tunnel authorization">
+<t>
+The OE gateway determines whether or not to create a tunnel based on 
+the destination address of each packet. Upon receiving a packet with a destination
+address not recently seen, the OE gateway performs a lookup in DNS for an
+authorization resource record (see <xref target="TXT"/>). The record is located using
+the IP address to perform a search in the in-addr.arpa (IPv4) or ip6.arpa
+(IPv6) maps. If an authorization record is found, the OE gateway 
+interprets this as a request for a tunnel to be formed.
+</t>
+</section> 
+
+<section title="Tunnel end-point discovery">
+
+<t>
+The authorization resource record also provides the address or name of the tunnel
+end point which should be used.
+</t>
+<t>
+The record may also provide the public RSA key of the tunnel end point
+itself. This is provided for efficiency only. If the public RSA key is not 
+present, the OE gateway performs a second lookup to find a KEY 
+resource record for the end point address or name.
+</t>
+<t>
+Origin and integrity protection of the resource records is provided by 
+DNSSEC (<xref target="RFC2535"/>). <xref target="nodnssec"/>
+documents an optional restriction on the tunnel end point if DNSSEC signatures
+are not available for the relevant records. 
+</t>
+
+</section>
+
+<section title="Caching of authorization results">
+<t>
+The OE gateway maintains a cache, in the forwarding plane, of
+source/destination pairs for which opportunistic encryption has been
+attempted. This cache maintains a record of whether or not OE was
+successful so that subsequent datagrams can be forwarded properly
+without additional delay. 
+</t>
+
+<t>
+Successful negotiation of OE instantiates a new security association. 
+Failure to negotiate OE results in creation of a 
+forwarding policy entry either to drop or transmit in the clear future
+datagrams. This negative cache is necessary to avoid the possibly lengthy process of repeatedly looking 
+up the same information.
+</t>
+
+<t>
+The cache is timed out periodically, as described in <xref target="teardown" />.
+This removes entries that are no longer
+being used and permits the discovery of changes in authorization policy.
+</t>
+</section>
+
+</section> <!-- "Model of operation" -->
+
+</section> <!-- "Overview" -->
+
+<section title="Protocol Specification">
+
+<t>
+The OE gateway is modeled to have a forwarding plane and a control
+plane. A control channel, such as PF_KEY, connects the two planes. 
+(See <xref target="RFC2367" />.)
+The forwarding plane performs per datagram operations. The control plane
+contains a keying daemon, such as ISAKMP/IKE, and performs all
+authorization, peer authentication and key derivation functions.   
+</t>
+
+<section title="Forwarding plane state machine">
+
+<t>
+Let the OE gateway maintain a collection of objects -- a superset of the
+security policy database (SPD) specified in <xref target="RFC2401" />. For
+each combination of source and destination address, an SPD
+object exists in one of five following states.
+Prior to forwarding each datagram, the responder uses the source and
+destination addresses to pick an entry from the SPD. 
+The SPD then determines if and how the packet is forwarded.
+</t>
+
+<!-- from file forwardingstate.txt -->
+<artwork><![CDATA[
+      .--------------. 	 
+      | non-existant |
+      |    policy    |
+      `--------------'
+             |        
+             | PF_ACQUIRE
+             |           
+             |<---------.
+             V          | new packet
+      .--------------.  | (maybe resend PF_ACQUIRE)
+      |  hold policy |--'                          
+      |              |--.                          
+      `--------------'   \  pass                   
+         |        |       \ msg    .---------.     
+         |        |        \       V         | forward
+         |        |         .-------------.  | packet 
+  create |        |         | pass policy |--'       
+  IPsec  |        |         `-------------'          
+  SA     |        |                                  
+         |         \                                 
+         |          \                                
+         V           \ 	deny                         
+   .---------.        \ msg                          
+   | encrypt |         \                             
+   | policy  |          \         ,---------.        
+   `---------'           \        |         | discard
+                          \       V         | packet 
+                           .-------------.  |        
+                           | deny policy |--'        
+                           '-------------'          
+]]></artwork>
+
+
+<section title="Non-existent policy">
+<t>
+If the gateway does not find an entry, then this policy applies.
+The gateway creates an entry with an initial state of "hold policy" and requests 
+keying material from the keying daemon. The gateway does not forward the datagram,
+rather it SHOULD attach the datagram to the SPD entry as the  "first" datagram and retain it 
+for eventual transmission in a new state. 
+
+</t>
+</section>
+
+<section title="Hold policy">
+<t>
+The gateway requests keying material. If the interface to the keying
+system is lossy (PF_KEY, for instance, can be), the implementation 
+SHOULD include a mechanism to retransmit the
+keying request at a rate limited to less than 1 request per second.
+The gateway does not forward the datagram. The gateway SHOULD attach the 
+datagram to the SPD entry as the "last" datagram where it is retained 
+for eventual transmission.
+If there is a datagram already so stored, then that already stored datagram is discarded.
+</t>
+<t>
+The rational behind saving the the "first" and "last" datagrams are as follows:
+The "first" datagram is probably a TCP SYN packet. Once there is keying
+established, the gateway will release this datagram, avoiding the need to 
+for the end-point to retransmit the datagram. In the case where the connection
+was not a TCP connection, buyt was instead a streaming protocol or a DNS request,
+the "last" datagram that was retained is likely the most recent data. The difference
+between "first" and "last" may also help the end-points determine
+which data awas dropped while negotiation took place.  
+</t>
+</section>
+
+<section title="Pass-through policy">
+<t>
+The gateway forwards the datagram using the normal forwarding table. 
+The gateway enters this state only by command from the keying daemon, 
+and upon entering this state, also forwards the "first" and "last" datagrams.
+</t>
+</section>
+
+<section title="Deny policy">
+<t>
+The gateway discards the datagram. The gateway enters this state only by
+command  
+from the keying daemon, and upon entering this state, discards the "first"
+and "last" datagrams.
+An implementation MAY provide the administator with a control to determine
+if further datagrams cause ICMP messages
+to be generated (i.e. ICMP Destination Unreachable, Communication
+Administratively Prohibited. type=3, code=13). 
+</t>
+</section>
+
+<section title="Encrypt policy">
+<t>
+The gateway encrypts the datagram using the indicated security association database
+(SAD) entry.  The gateway enters this state only by command from the keying daemon, and upon entering
+this state, releases and forwards the "first" and "last" datagrams using the
+new encrypt policy.  
+</t>
+<t>
+If the associated SAD entry expires because of byte, packet or time limits, then
+the entry returns to the Hold policy, and an expire message is sent to the keying daemon.
+</t>
+</section>
+
+<t>
+All states may be created directly by the keying daemon while acting as a
+gateway. 
+</t>
+
+</section> <!-- "Datagram state machine" -->
+
+
+<section anchor="initclasses" title="Keying Daemon -- initiator">
+<t>
+Let the keying daemon maintain a collection of objects. Let them be
+called "connections" or "conn"s. There are two categories of
+connection objects: classes and instances. A class represents an
+abstract policy - what could be. An instance represents an actual connection -  
+what is implemented at the time.
+</t>
+
+<t>
+Let there be two further subtypes of connections: keying channels (Phase
+1 SAs) and data channels (Phase 2 SAs). Each data channel object may have 
+a corresponding SPD and SAD entry maintained by the datagram state machine.
+</t>
+
+<t>
+For the purposes of opportunistic encryption, there MUST, at least, be
+connection classes known as "deny", "always-clear-text", "OE-permissive", and 
+"OE-paranoid".  
+The latter two connection classes define a set of source and/or destination
+addresses for which opportunistic encryption will be attempted.
+The administrator MAY set policy options in a number of additional places.
+An implementation MAY create additional connection classes to further refine
+these policies.
+</t>
+
+<t>
+The simplest system may need only the "OE-permissive" connection, and would
+list its own (single) IP address as the source address of this policy and
+the wild-card address 0.0.0.0/0 as the destination IPv4 address. That is, the
+simplest policy is to try opportunistic encryption with all destinations. 
+</t>
+
+<t>
+The distinction between permissive and paranoid OE use will become clear 
+in the state transition differences. In general a permissive OE will, on
+failure, install a pass-through policy, while a paranoid OE will, on failure, 
+install a drop policy.
+</t>
+
+<t>
+In this description of the keying machine's state transitions, the states
+associated with the keying system itself are omitted because they are best documented in the keying system 
+(<xref target="RFC2407" />, 
+<xref target="RFC2408" /> and <xref target="RFC2409" /> for ISAKMP/IKE),
+and the details are keying system specific. Opportunistic encryption is not
+dependent upon any specific keying protocol, but this document does provide
+requirements for those using ISAKMP/IKE to assure that implementations inter-operate.
+</t>
+<t>
+The state transitions that may be involved in communicating with the
+forwarding plane are omitted. PF_KEY and similar protocols have their own
+set of states required for message sends and completion notifications.
+</t>
+<t>
+Finally, the retransmits and recursive lookups that are normal for DNS are 
+not included in this description of the state machine.
+</t>
+
+<!-- from file initiatorstate.txt -->
+<artwork><![CDATA[
+
+                       |
+	               | PF_ACQUIRE
+		       |     
+                       V
+                .---------------.       
+                |  non-existant |
+                |  connection   |
+                `---------------'
+                 |      |      |
+          send   ,      |      \
+expired   pass  /       |       \ send
+conn.     msg  /        |        \ deny
+  ^           /         |         \ msg
+  |          V          | do       \ 		 
+.---------------.       | DNS       \   .---------------.  
+|  clear-text   |	| lookup     `->|     deny      |---> expired
+|  connection   |	| for 	        |  connection   |     connection
+`---------------'	| destination   `---------------'
+   ^ ^                  |                   ^
+   | | no record        |                   |
+   | | OE-permissive    V                   | no record
+   | |            .---------------.         | OE-paranoid
+   | `------------|  potential OE |---------'
+   |              |  connection   |         ^
+   |              `---------------'         |
+   |                    |                   |
+   |                    | got TXT record    | DNSSEC failure
+   |                    | reply             |
+   |                    V                   | wrong 
+   |              .---------------.         | failure
+   |              |  authenticate |---------'
+   |              | & parse TXT RR|         ^
+   | repeated     `---------------'         |
+   | ICMP               |                   |
+   | failures           | initiate IKE to   |                         
+   | (short-timeout)    | responder         |                         
+   |                    V                   |                          
+   | phase-2      .---------------.         | failure                       
+   | failure      |   pending     |---------'                          
+   | (normal      |     OE        |         ^                          
+   |  timeout)    |               |invalid  | phase-2 failure (short-timeout)
+   |              |               |<--.SPI  | ICMP failures (normal timeout)
+   |              |               |   |     |                          
+   |              | +=======+     |---'     |                          
+   |              | |  IKE  |     |   ^     |                          
+   `--------------| | states|---------------'                          
+                  | +=======+     |   |                                
+                  `---------------'   |                                
+                        | IPsec SA    | invalid SPI                    
+                        | established |                                
+	                V             | rekey time                     
+                  .--------------.    |                                
+                  |   keyed      |<---|-------------------------------.
+                  |  connection  |----'                               |
+                  `--------------'                                    |
+                        | timer                                       |
+                        |                                             |
+                        V                                             |
+                  .--------------.     connection still active        |
+  clear-text----->|   expired    |------------------------------------'
+        deny----->|  connection  |
+                  `--------------'
+                        | dead connected - deleted
+                        V
+]]></artwork>
+
+
+<section title="Nonexistent connection">
+<t>
+There is no connection instance for a given source/destination address pair.
+Upon receipt of a request for keying material for this
+source/destination pair, the initiator searches through the connection classes to
+determine the most appropriate policy. Upon determining an appropriate
+connection class, an instance object is created of that type. 
+Both of the OE types result in a potential OE connection.
+</t>
+<t>Failure to find an appropriate connection class results in an
+administrator defined default. 
+</t>
+<t>
+In each case, when the initiator finds an appropriate class for the new flow, 
+an instance connection is made of the class which matched.
+</t>
+</section>
+
+<section title="Clear-text connection">
+<t>
+The non-existent connection makes a transition to this state when an
+always-clear-text class is instantiated, or when an OE-permissive 
+connection fails. During the transition, the initiator creates a pass-through
+policy object in the forwarding plane for the appropriate flow.
+</t>
+<t>
+Timing out is the only way to leave this state
+(see <xref target="expiring" />).
+</t>
+</section>
+
+<section title="Deny connection">
+<t>
+The empty connection makes a transition to this state when a
+deny class is instantiated, or when an OE-paranoid connection fails. 
+During the transition, the initiator creates a deny policy object in the forwarding plane 
+for the appropriate flow.  
+</t>
+<t>
+Timing out is the only way to leave this state 
+(see <xref target="expiring" />).
+</t>
+</section>
+
+<section title="Potential OE connection">
+<t>
+The empty connection makes a transition to this state when one of either OE class is instantiated.
+During the transition to this state, the initiator creates a hold policy object in the 
+forwarding plane for the appropriate flow.  
+</t>
+<t>
+In addition, when making a transition into this state, DNS lookup is done in
+the reverse-map for a TXT delegation resource record (see <xref target="TXT" />).
+The lookup key is the destination address of the flow.
+</t>
+<t>
+There are three ways to exit this state: 
+<list style="numbers">
+<t>DNS lookup finds a TXT delegation resource record.</t>
+<t>DNS lookup does not find a TXT delegation resource record.</t>
+<t>DNS lookup times out.</t>
+</list>
+</t>
+
+<t>
+Based upon the results of the DNS lookup, the potential OE connection makes a
+transition to the pending OE connection state.  The conditions for a
+successful DNS look are:
+<list style="numbers">
+<t>DNS finds an appropriate resource record</t>
+<t>It is properly formatted according to <xref target="TXT" /></t>
+<t> if DNSSEC is enabled, then the signature has been vouched for.</t>
+</list>
+
+Note that if the initiator does not find the public key 
+present in the TXT delegation record, then the public key must 
+be looked up as a sub-state. Only successful completion of all the 
+DNS lookups is considered a success.
+</t>
+<t>
+If DNS lookup does not find a resource record or DNS times out, then the 
+initiator considers the receiver not OE capable. If this is an OE-paranoid instance, 
+then the potential OE connection makes a transition to the deny connection state.
+If this is an OE-permissive instance, then the potential OE connection makes a transition to the
+clear-text connection state.
+</t>
+<t>
+If the initiator finds a resource record but it is not properly formatted, or
+if DNSSEC is 
+enabled and reports a failure to authenticate, then the potential OE
+connection makes a 
+transition to the deny connection state. This action SHOULD be logged. If the
+administrator wishes to override this transition between states, then an
+always-clear class can be installed for this flow. An implementation MAY make
+this situation a new class.
+</t>
+
+<section anchor="nodnssec" title="Restriction on unauthenticated TXT delegation records">
+<t>
+An implementation SHOULD also provide an additional administrative control
+on delegation records and DNSSEC. This control would apply to delegation
+records (the TXT records in the reverse-map) that are not protected by
+DNSSEC.
+Records of this type are only permitted to delegate to their own address as
+a gateway. When this option is enabled, an active attack on DNS will be
+unable to redirect packets to other than the original destination.
+<!-- This was asked for by Bill Sommerfeld -->
+</t>
+</section>
+</section>
+
+<section title="Pending OE connection">
+<t>
+The potential OE connection makes a transition to this state when 
+the initiator determines that all the information required from the DNS lookup is present.
+Upon entering this state, the initiator attempts to initiate keying to the gateway
+provided.  
+</t>
+<t>
+Exit from this state occurs either with a successfully created IPsec SA, or
+with a failure of some kind.  Successful SA creation results in a transition
+to the key connection state.
+</t>
+<t>
+Three failures have caused significant problems. They are clearly not the
+only possible failures from keying.
+</t>
+<t>
+Note that if there are multiple gateways available in the TXT delegation
+records, then a failure can only be declared after all have been
+tried. Further, creation of a phase 1 SA does not constitute success. A set
+of phase 2 SAs (a tunnel) is considered success.
+</t>
+<t>
+The first failure occurs when an ICMP port unreachable is consistently received
+without any other communication, or when there is silence from the remote
+end. This usually means that either the gateway is not alive, or the
+keying daemon is not functional. For an OE-permissive connection, the initiator makes a transition
+to the clear-text connection but with a low lifespan. For an OE-pessimistic connection,
+the initiator makes a transition to the deny connection again with a low lifespan. The
+lifespan in both 
+cases is kept low because the remote gateway may
+be in the process of rebooting or be otherwise temporarily unavailable. 
+</t>
+<t>
+The length of time to wait for the remote keying daemon to wake up is
+a matter of some debate. If there is a routing failure, 5 minutes is usually long
+enough for the network to
+re-converge. Many systems can reboot in that amount of
+time as well. However, 5 minutes is far too long for most users to wait to
+hear that they can not connect using OE. Implementations SHOULD make this a
+tunable parameter.
+</t>
+<t>
+The second failure occurs after a phase 1 SA has been created, but there is 
+either no response to the phase 2 proposal, or the initiator receives a 
+negative notify (the notify must be 
+authenticated). The remote gateway is not prepared to do OE at this time. 
+As before, the initiator makes a transition to the clear-text or the deny 
+connection based upon connection class, but this
+time with a normal lifespan. 
+</t>
+<t>
+The third failure occurs when there is signature failure while authenticating
+the remote gateway. This can occur when there has been a 
+key roll-over, but DNS has not caught up. In this case again, the initiator makes a 
+transition to the clear-text or the deny connection based
+upon the connection class. However, the lifespan depends upon the remaining
+time to live in the DNS. (Note that DNSSEC signed resource records have a different
+expiry time than non-signed records.) 
+<!-- dig @gateway would also work here -->
+</t>
+
+</section>
+
+<section anchor="keyed" title="Keyed connection">
+<t>
+The pending OE connection makes a transition to this state when 
+session keying material (the phase 2 SAs) is derived. The initiator creates an encrypt
+policy in the forwarding plane for this flow.
+</t>
+<t>
+There are three ways to exit this state. The first is by receipt of an
+authenticated delete message (via the keying channel) from the peer. This is
+normal teardown and results in a transition to the expired connection state.
+</t>
+<t>
+The second exit is by expiry of the forwarding plane keying material. This
+starts a re-key operation with a transition back to pending OE
+connection. In general, the soft expiry occurs with sufficient time left
+to continue to use the keys. A re-key can fail, which may
+result in the connection failing to clear-text or deny as
+appropriate. In the event of a failure, the forwarding plane
+policy does not change until the phase 2 SA (IPsec SA) reaches its
+hard expiry.
+</t>
+<t>
+The third exit is in response to a negotiation from a remote
+gateway. If the forwarding plane signals the control plane that it has received an
+unknown SPI from the remote gateway, or an ICMP is received from the remote gateway
+indicating an unknown SPI, the initiator should consider that 
+the remote gateway has rebooted or restarted. Since these 
+indications are easily forged, the implementation must 
+exercise care.  The initiator should make a cautious 
+(rate-limited) attempt to re-key the connection. 
+</t>
+</section>
+
+<section anchor="expiring" title="Expiring connection">
+<t>
+The initiator will periodically place each of the deny, clear-text, and keyed
+connections into this  
+sub-state. See <xref target="teardown" /> for more details of how often this
+occurs. 
+The initiator queries the forwarding plane for last use time of the
+appropriate 
+policy. If the last use time is relatively recent, then the connection
+returns to the 
+previous deny, clear-text or keyed connection state. If not, then the
+connection enters 
+the expired connection state. 
+</t>
+<t>
+The DNS query and answer that lead to the expiring connection state are also
+examined. The DNS query may become stale. (A negative, i.e. no such record, answer
+is valid for the period of time given by the MINIMUM field in an attached SOA 
+record. See <xref target="RFC1034" /> section 4.3.4.)
+If the DNS query is stale, then a new query is made. If the results change, then the connection 
+makes a transition to a new state as described in potential OE connection state.
+</t>
+<t> 
+Note that when considering how stale a connection is, both outgoing SPD and
+incoming SAD must be queried as some flows may be unidirectional for some time.
+</t>
+<t>
+Also note that the policy at the forwarding plane is not updated unless there
+is a conclusion that there should be a change.
+</t>
+
+</section>
+<section title="Expired connection">
+<t>
+Entry to this state occurs when no datagrams have been forwarded recently via the
+appropriate SPD and SAD objects. The objects in the forwarding plane are
+removed (logging any final byte and packet counts if appropriate) and the
+connection instance in the keying plane is deleted. 
+</t>
+<t>
+The initiator sends an ISAKMP/IKE delete to clean up the phase 2 SAs as described in
+<xref target="teardown" />. 
+</t>
+<t>
+Whether or not to delete the phase 1 SAs
+at this time is left as a local implementation issue. Implementations
+that do delete the phase 1 SAs MUST send authenticated delete messages to
+indicate that they are doing so.  There is an advantage to keeping
+the phase 1 SAs until they expire - they may prove useful again in the 
+near future.
+</t>
+</section>
+
+</section> <!-- "Keying state machine - initiator" -->
+
+<section title="Keying Daemon - responder">
+<t>
+The responder has a set of objects identical to those of the initiator.
+</t>
+<t>
+The responder receives an invitation to create a keying channel from an initiator. 
+</t>
+
+<!-- from file responderstate.txt -->
+<artwork><![CDATA[
+                |
+                | IKE main mode 
+                |  phase 1
+                V
+        .-----------------.  
+        | unauthenticated | 
+        |     OE peer     |
+        `-----------------'
+                |
+                | lookup KEY RR in in-addr.arpa 
+                |             (if ID_IPV4_ADDR)
+                | lookup KEY RR in forward
+                |             (if ID_FQDN)
+                V
+        .-----------------.  RR not found
+        |   received DNS  |---------------> log failure
+        |     reply       | 
+        `----+--------+---'
+     phase 2 |        \      misformatted 
+    proposal |         `------------------> log failure
+             V
+    .----------------.
+    |  authenticated |  identical initiator 
+    |     OE peer    |--------------------> initiator 
+    `----------------'  connection found    state machine
+         |
+         | look for TXT record for initiator
+	 |
+         V  
+   .---------------.
+   |  authorized   |---------------------> log failure
+   |    OE peer    |
+   `---------------'
+         |
+         |
+         V
+    potential OE
+    connection in
+    initiator state
+	machine
+
+
+$Id: draft-richardson-ipsec-opportunistic.xml,v 1.1 2004/03/15 20:35:24 as Exp $
+]]></artwork>
+
+
+<section title="Unauthenticated OE peer">
+<t>
+Upon entering this state, the responder starts a DNS lookup for a KEY record for the
+initiator. 
+The responder looks in the reverse-map for a KEY record for the initiator if the
+initiator has offered an ID_IPV4_ADDR, and in the forward map if the
+initiator has offered an ID_FQDN type. (See <xref target="RFC2407" /> section 
+4.6.2.1.)
+</t>
+<t>
+The responder exits this state upon successful receipt of a KEY from DNS, and use of the key 
+to verify the signature of the initiator.
+</t>
+
+<!--
+<t>
+The public key that is retrieved should be stored in stable storage for an
+administratively defined period of time, (typically several months if
+possible). If a key has previously been stored on disk, then the returned key
+should be compared to what has been received, and the key considered valid
+only if they match.  
+</t>
+-->
+
+<t>
+Successful authentication of the peer results in a transition to the
+authenticated OE Peer state.
+</t>
+<t>
+Note that the unauthenticated OE peer state generally occurs in the middle of the key negotiation
+protocol. It is really a form of pseudo-state.
+</t>
+</section>
+
+<section title="Authenticated OE Peer">
+<t>
+The peer will eventually propose one or more phase 2 SAs. The responder uses the source and
+destination address in the proposal to 
+finish instantiating the connection state
+using the connection class table.
+The responder MUST search for an identical connection object at this point. 
+</t>
+<t> 
+If an identical connection is found, then the responder deletes the old instance, 
+and the new object makes a transition to the pending OE connection state. This means
+that new ISAKMP connections with a given peer will always use the latest
+instance, which is the correct one if the peer has rebooted in the interim.
+</t>
+<t> 
+If an identical connection is not found, then the responder makes the transition according to the 
+rules given for the initiator.
+</t>
+<t> 
+Note that if the initiator is in OE-paranoid mode and the responder is in 
+either always-clear-text or deny, then no communication is possible according
+to policy. An implementation is permitted to create new types of policies 
+such as "accept OE but do not initiate it". This is a local matter.
+ </t>
+</section>
+
+</section> <!-- "Keying state machine - responder" -->
+
+<section anchor="teardown" title="Renewal and teardown">
+  <section title="Aging">
+<t>
+A potentially unlimited number of tunnels may exist. In practice, only a few
+tunnels are used during a period of time. Unused tunnels MUST, therefore, be
+torn down. Detecting when tunnels are no longer in use is the subject of this section.
+</t>
+
+<t>
+There are two methods for removing tunnels: explicit deletion or expiry. 
+</t>
+
+<t>
+Explicit deletion requires an IKE delete message. As the deletes
+MUST be authenticated, both ends of the tunnel must maintain the 
+key channel (phase 1 ISAKMP SA). An implementation which refuses to either maintain or
+recreate the keying channel SA will be unable to use this method.
+</t>
+
+<t>
+The tunnel expiry method simply allows the IKE daemon to
+expire normally without attempting to re-key it.
+</t>
+
+<t>
+Regardless of which method is used to remove tunnels, the implementation MUST
+a method to determine if the tunnel is still in use.  The specifics are a
+local matter, but  the FreeS/WAN project uses the following criteria. These
+criteria are currently implemented in the key management daemon, but could
+also be implemented at the SPD layer using an idle timer.
+</t>
+
+<t>
+Set a short initial (soft) lifespan of 1 minute since many net flows last
+only a few seconds.
+</t>
+
+<t>
+At the end of the lifespan, check to see if the tunnel was used by
+traffic in either direction during the last 30 seconds. If so, assign a
+longer tentative lifespan of 20 minutes after which, look again. If the
+tunnel is not in use, then close the tunnel.
+</t>
+
+<t>
+The expiring state in the key management
+system (see <xref target="expiring" />) implements these timeouts.
+The timer above may be in the forwarding plane, 
+but then it must be re-settable. 
+</t>
+
+<t>
+The tentative lifespan is independent of re-keying; it is just the time when
+the tunnel's future is next considered. 
+(The term lifespan is used here rather than lifetime for this reason.) 
+Unlike re-keying, this tunnel use check is not costly and should happen
+reasonably frequently.
+</t> 
+
+<t>
+A multi-step back-off algorithm is not considered worth the effort here.
+</t>
+
+<t>
+If the security gateway and the client host are the
+same and not a Bump-in-the-Stack or Bump-in-the-Wire implementation, tunnel
+teardown decisions MAY pay attention to TCP connection status as reported
+by the local TCP layer.  A still-open TCP connection is almost a guarantee that more traffic is
+expected. Closing of the only TCP connection through a tunnel is a
+strong hint that no more traffic is expected.
+</t>
+
+</section> <!-- "Aging" -->
+
+<section title="Teardown and cleanup">
+
+<t>
+Teardown should always be coordinated between the two ends of the tunnel by 
+interpreting and sending delete notifications. There is a
+detailed sub-state in the expired connection state of the key manager that
+relates to retransmits of the delete notifications, but this is considered to 
+be a keying system detail.
+</t>
+
+<t>
+On receiving a delete for the outbound SAs of a tunnel (or some subset of
+them), tear down the inbound ones also and notify the remote end with a
+delete. If the local system receives a delete for a tunnel which is no longer in
+existence, then two delete messages have crossed paths. Ignore the delete.
+The operation has already been completed. Do not generate any messages in this
+situation. 
+</t>
+<t>
+Tunnels are to be considered as bidirectional entities, even though the
+low-level protocols don't treat them this way. 
+</t>
+
+<t>
+When the deletion is initiated locally, rather than as a
+response to a received delete, send a delete for (all) the
+inbound SAs of a tunnel.  If the local system does not receive a responding delete 
+for the outbound SAs, try re-sending the original
+delete. Three tries spaced 10 seconds apart seems a reasonable
+level of effort. A failure of the other end to respond after 3 attempts, 
+indicates that the possibility of further communication is unlikely. Remove the outgoing SAs.
+(The remote system may be a mobile node that is no longer present or powered on.)
+</t>
+
+<t>
+After re-keying, transmission should switch to using the new
+outgoing SAs (ISAKMP or IPsec) immediately, and the old leftover
+outgoing SAs should be cleared out promptly (delete should be sent
+for the outgoing SAs) rather than waiting for them to expire. This
+reduces clutter and minimizes confusion for the operator doing diagnostics.
+</t>
+
+</section>
+
+</section>
+
+</section> <!-- "Specification" -->
+
+<section title="Impacts on IKE">
+
+  <section title="ISAKMP/IKE protocol">
+    <t>
+    The IKE wire protocol needs no modifications. The major changes are
+    implementation issues relating to how the proposals are interpreted, and from
+    whom they may come.
+    </t>
+    <t>
+    As opportunistic encryption is designed to be useful between peers without
+    prior operator configuration, an IKE daemon must be prepared to negotiate
+    phase 1 SAs with any node. This may require a large amount of resources to 
+    maintain cookie state, as well as large amounts of entropy for nonces,
+    cookies and so on. 
+    </t>
+    <t>
+    The major changes to support opportunistic encryption are at the IKE daemon
+    level. These changes relate to handling of key acquisition requests, lookup
+    of public keys and TXT records, and interactions with firewalls and other
+    security facilities that may be co-resident on the same gateway.
+    </t>
+  </section>
+
+  <section title="Gateway discovery process">
+  <t>
+  In a typical configured tunnel, the address of SG-B is provided
+  via configuration. Furthermore, the mapping of an SPD entry to a gateway is
+  typically a 1:1 mapping. When the 0.0.0.0/0 SPD entry technique is used, then
+  the mapping to a gateway is determined by the reverse DNS records.
+  </t>
+  <t>
+  The need to do a DNS lookup and wait for a reply will typically introduce a
+  new state and a new event source (DNS replies) to IKE. Although a
+synchronous DNS request can be implemented for proof of concept, experience
+is that it can cause very high latencies when a queue of queries must
+all timeout in series. 
+  </t>
+  <t> 
+  Use of an asynchronous DNS lookup will also permit overlap of DNS lookups with
+  some of the protocol steps.
+  </t>
+  </section>
+
+  <section title="Self identification">
+  <t>
+     SG-A will have to establish its identity. Use an
+     IPv4 ID in phase 1. 
+  </t>
+  <t> There are many situations where the administrator of SG-A may not be
+      able to control the reverse DNS records for SG-A's public IP address.
+      Typical situations include dialup connections and most residential-type broadband Internet access 
+      (ADSL, cable-modem) connections. In these situations, a fully qualified domain
+      name that is under the control of SG-A's administrator may be used
+      when acting as an initiator only.
+      The FQDN ID should be used in phase 1. See <xref target="fqdn" />
+      for more details and restrictions.
+  </t>
+  </section>
+
+  <section title="Public key retrieval process">
+  <t>
+     Upon receipt of a phase 1 SA proposal with either an IPv4 (IPv6) ID or
+     an FQDN ID, an IKE daemon needs to examine local caches and
+     configuration files to determine if this is part of a configured tunnel.
+     If no configured tunnels are found, then the implementation should attempt to retrieve
+     a KEY record from the reverse DNS in the case of an IPv4/IPv6 ID, or 
+     from the forward DNS in the case of FQDN ID.
+  </t>
+  <t> 
+     It is reasonable that if other non-local sources of policy are used
+     (COPS, LDAP), they be consulted concurrently but some
+     clear ordering of policy be provided. Note that due to variances in
+     latency, implementations must wait for positive or negative replies from all sources
+     of policy before making any decisions.
+  </t>
+  </section>
+  
+  <section title="Interactions with DNSSEC">
+  <t>
+     The implementation described (1.98) neither uses DNSSEC directly to
+     explicitly verify the authenticity of zone information, nor uses the NXT
+     records to provide authentication of the absence of a TXT or KEY
+     record. Rather, this implementation uses a trusted path to a DNSSEC
+     capable caching resolver. 
+  </t>
+  <t> 
+     To distinguish between an authenticated and an unauthenticated DNS
+     resource record, a stub resolver capable of returning DNSSEC
+     information MUST be used.
+  </t>
+     
+  </section>
+
+<!--
+  <section title="Interactions with COPS">
+  <t>
+     At this time there is no experience with implementations that interact
+     with COPS Policy Decision Points (PDP) <xref target="RFC2748" />. It is
+     suggested that it may be 
+     appropriate for many of 
+     the policy and discovery mechanisms outlined here to be done by a PDP.
+     In this context, the IKE daemon present in the Policy Enforcement Point
+     (PEP) may not need any modifications.
+  </t>
+  </section>
+-->
+
+  <section title="Required proposal types">
+
+    <section anchor="phase1id" title="Phase 1 parameters">
+      <t>
+        Main mode MUST be used.
+      </t>
+      <t>
+	The initiator MUST offer at least one proposal using some combination
+	of: 3DES, HMAC-MD5 or HMAC-SHA1, DH group 2 or 5. Group 5 SHOULD be
+	proposed first.
+	<xref target="RFC3526" />
+      </t>
+      <t>
+	The initiator MAY offer additional proposals, but the cipher MUST not
+	be weaker than 3DES. The initiator SHOULD limit the number of proposals
+	such that the IKE datagrams do not need to be fragmented.
+      </t>
+      <t>
+	The responder MUST accept one of the proposals. If any configuration
+	of the responder is required then the responder is not acting in an
+	opportunistic way. 
+      </t>
+      <t>
+        The initiator SHOULD use an ID_IPV4_ADDR (ID_IPV6_ADDR for IPv6) of the external
+        interface of the initiator for phase 1. (There is an exception, see <xref
+        target="fqdn" />.) The authentication method MUST be RSA public key signatures. 
+        The RSA key for the initiator SHOULD be placed into a DNS KEY record in
+	the reverse space of the initiator (i.e. using in-addr.arpa or
+        ip6.arpa).
+      </t>
+    </section>
+
+    <section anchor="phase2id" title="Phase 2 parameters">
+      <t>
+        The initiator MUST propose a tunnel between the ultimate
+        sender ("Alice" or "A") and ultimate recipient ("Bob" or "B")
+        using 3DES-CBC
+        mode, MD5 or SHA1 authentication. Perfect Forward Secrecy MUST be specified.
+      </t>
+      <t>
+        Tunnel mode MUST be used.
+      </t>
+      <t>
+        Identities MUST be ID_IPV4_ADDR_SUBNET with the mask being /32.
+      </t>
+      <t>
+        Authorization for the initiator to act on Alice's behalf is determined by
+        looking for a TXT record in the reverse-map at Alice's IP address.
+      </t>
+      <t>
+        Compression SHOULD NOT be mandatory. It MAY be offered as an option.
+      </t>
+    </section>
+  </section>
+
+</section>
+
+<section title="DNS issues">
+  <section anchor="KEY" title="Use of KEY record">
+  <t>
+    In order to establish their own identities, security gateways SHOULD publish
+    their public keys in their reverse DNS via 
+    DNSSEC's KEY record.
+    See section 3 of <xref target="RFC2535">RFC 2535</xref>.
+  </t>	
+  <t>
+    <preamble>For example:</preamble>
+    <artwork><![CDATA[
+KEY 0x4200 4 1 AQNJjkKlIk9...nYyUkKK8
+]]></artwork>
+
+  <list style="hanging">
+  <t hangText="0x4200:"> The flag bits, indicating that this key is prohibited
+    for confidentiality use (it authenticates the peer only, a separate
+    Diffie-Hellman exchange is used for
+    confidentiality), and that this key is associated with the non-zone entity
+    whose name is the RR owner name. No other flags are set.</t>
+  <t hangText="4:">This indicates that this key is for use by IPsec.</t>
+  <t hangText="1:">An RSA key is present.</t>
+  <t hangText="AQNJjkKlIk9...nYyUkKK8:">The public key of the host as described in <xref target="RFC3110" />.</t> 
+  </list>
+  </t>
+  <t>Use of several KEY records allows for key rollover. The SIG Payload in
+  IKE phase 1 SHOULD be accepted if the public key given by any KEY RR
+  validates it.
+  </t>
+  </section>
+
+  <section anchor="TXT" title="Use of TXT delegation record">
+    <t>
+If, for example, machine Alice wishes SG-A to act on her behalf, then
+she publishes a TXT record to provide authorization for SG-A to act on
+Alice's behalf. Similarly for Bob and SG-B.
+</t>
+
+<t>
+These records are located in the reverse DNS (in-addr.arpa or ip6.arpa) for their
+respective IP addresses.  The reverse DNS SHOULD be secured by DNSSEC.
+DNSSEC is required to defend against active attacks.
+    </t>
+    <t>
+      If Alice's address is P.Q.R.S, then she can authorize another node to
+      act on her behalf by publishing records at:
+           <artwork><![CDATA[
+S.R.Q.P.in-addr.arpa
+          ]]></artwork>
+    </t>
+
+    <t>
+    The contents of the resource record are expected to be a string that
+    uses the following syntax, as suggested in <xref target="RFC1464">RFC1464</xref>.
+    (Note that the reply to query may include other TXT resource
+    records used by other applications.)
+
+    <figure anchor="txtformat" title="Format of reverse delegation record">
+           <artwork><![CDATA[
+X-IPsec-Server(P)=A.B.C.D KEY
+          ]]></artwork>
+    </figure>
+    </t>
+
+    where the record is formed by the following fields:
+
+    <list style="hanging"> 
+      <t hangText="P:"> Specifies a precedence for this record.  This is
+      similar to MX record preferences.  Lower numbers have stronger
+      preference. 
+      </t>  
+
+      <t hangText="A.B.C.D:"> Specifies the IP address of the Security Gateway
+      for this client machine.
+      </t>
+
+      <t hangText="KEY:"> Is the encoded RSA Public key of the Security
+      Gateway. The key is provided here to avoid a second DNS lookup. If this
+      field is absent, then a KEY resource record should be looked up in the
+      reverse-map of A.B.C.D. The key is transmitted in base64 format.
+      </t> 
+    </list>
+
+    <t>
+  	The fields of the record MUST be separated by whitespace. This
+        MAY be: space, tab, newline, or carriage return. A space is preferred.
+    </t>
+
+    <t>
+	In the case where Alice is located at a public address behind a 
+	security gateway that has no fixed address (or no control over its
+	reverse-map), then Alice may delegate to a public key by domain name.
+
+    <figure anchor="txtfqdnformat"
+            title="Format of reverse delegation record (FQDN version)">
+           <artwork><![CDATA[
+X-IPsec-Server(P)=@FQDN KEY
+          ]]></artwork>
+    </figure>
+    </t>
+
+    <list style="hanging"> 
+      <t hangText="P:"> Is as above.
+      </t>  
+
+      <t hangText="FQDN:"> Specifies the FQDN that the Security Gateway
+      will identify itself with. 
+      </t>
+
+      <t hangText="KEY:"> Is the encoded RSA Public key of the Security
+      Gateway. </t> 
+    </list>
+
+    <t>
+	If there is more than one such TXT record with strongest (lowest
+	numbered) precedence, one Security Gateway is picked arbitrarily from
+	those specified in the strongest-preference records. 
+    </t>
+ 
+  <section title="Long TXT records">
+  <t>
+  When packed into transport format, TXT records which are longer than 255
+  characters are divided into smaller &lt;character-strings&gt;.
+  (See <xref target="RFC1035" /> section 3.3 and 3.3.14.) These MUST
+  be reassembled into a single string for processing.
+  Whitespace characters in the base64 encoding are to be ignored.
+  </t>
+  </section>
+
+  <section title="Choice of TXT record">
+  <t>
+	It has been suggested to use the KEY, OPT, CERT, or KX records
+	instead of a TXT record. None is satisfactory.
+  </t>
+  <t> The KEY RR has a protocol field which could be used to indicate a new protocol, 
+and an algorithm field which could be used to
+        indicate different contents in the key data. However, the KEY record
+	is clearly not intended for storing what are really authorizations,
+	it is just for identities. Other uses have been discouraged.
+  </t>
+  <t> OPT resource records, as defined in <xref target="RFC2671" /> are not 
+  intended to be used for storage of information. They are not to be loaded, 
+	cached or forwarded.  They are, therefore, inappropriate for use here.
+  </t>
+  <t>
+    CERT records <xref target="RFC2538" /> can encode almost any set of
+    information. A custom type code could be used permitting any suitable
+    encoding to be stored, not just X.509.  According to
+    the RFC, the certificate RRs are to be signed internally which may add undesirable 
+and unnecessary bulk. Larger DNS records may require TCP instead of UDP transfers.
+  </t>
+  <t>
+    At the time of protocol design, the CERT RR was not widely deployed and
+    could not be counted upon. Use of CERT records will be investigated,
+    and may be proposed in a future revision of this document.
+  </t>
+  <t>
+    KX records are ideally suited for use instead of TXT records, but had not been deployed at
+    the time of implementation.
+<!-- Jakob Schlyter <j@crt.se> confirmed -->
+  </t>	
+  </section>
+  </section>
+
+  <section anchor="fqdn" title="Use of FQDN IDs">
+    <t>
+      Unfortunately, not every administrator has control over the contents
+      of the reverse-map.  Where the initiator (SG-A) has no suitable reverse-map, the
+      authorization record present in the reverse-map of Alice may refer to a
+      FQDN instead of an IP address.
+    </t>
+    <t>
+      In this case, the client's TXT record gives the fully qualified domain
+      name (FQDN) in place of its security gateway's IP address. 
+      The initiator should use the ID_FQDN ID-payload in phase 1.
+      A forward lookup for a KEY record on the FQDN must yield the
+      initiator's public key. 
+    </t>
+    <t>
+      This method can also be used when the external address of SG-A is
+      dynamic. 
+    </t>
+    <t>
+      If SG-A is acting on behalf of Alice, then Alice must still delegate
+      authority for SG-A to do so in her reverse-map. When Alice and SG-A
+      are one and the same (i.e. Alice is acting as an end-node) then there
+      is no need for this when initiating only. </t>
+    <t>However, Alice must still delegate to  herself if she wishes others to
+       initiate OE to her.  See <xref target="txtfqdnformat" />.
+    </t>
+    <
+  </section> 
+
+<section title="Key roll-over">
+<t>
+Good cryptographic hygiene says that one should replace public/private key pairs
+periodically. Some administrators may wish to do this as often as daily. Typical DNS
+propagation delays are determined by the SOA Resource Record MINIMUM
+parameter, which controls how long DNS replies may be cached. For reasonable
+operation of DNS servers, administrators usually want this value to be at least several 
+hours, sometimes as a long as a day. This presents a problem - a new key MUST
+not be used prior to it propagating through DNS.
+</t>
+<t>
+This problem is dealt with by having the Security Gateway generate a new
+public/private key pair at least MINIMUM seconds in advance of using it. It
+then adds this key to the DNS (both as a second KEY record and in additional TXT
+delegation records) at key generation time. Note: only one key is allowed in
+each TXT record.
+</t>
+<t>
+When authenticating, all gateways MUST have available all public keys 
+that are found in DNS for this entity. This permits the authenticating end
+to check both the key for "today" and the key for "tomorrow". Note that it is 
+the end which is creating the signature (possesses the private key) that
+determines which key is to be used.
+</t>
+
+  </section>
+</section>
+
+
+<section title="Network address translation interaction">
+  <t>
+     There are no fundamentally new issues for implementing opportunistic encryption
+     in the presence of network address translation. Rather there are 
+     only the regular IPsec issues with NAT traversal.
+  </t>
+  <t>
+     There are several situations to consider for NAT.
+  </t>
+  <section title="Co-located NAT/NAPT">
+    <t>
+       If a security gateway is also performing network address translation on
+       behalf of an end-system, then the packet should be translated prior to
+       being subjected to opportunistic encryption. This is in contrast to
+       typically configured tunnels which often exist to bridge islands of 
+       private network address space. The security gateway will use the translated source
+       address for phase 2, and so the responding security gateway will look up that address to
+       confirm SG-A's authorization. 
+    </t>
+    <t> In the case of NAT (1:1), the address space into which the
+        translation is done MUST be globally unique, and control over the
+	reverse-map is assumed.
+        Placing of TXT records is possible.
+    </t>
+    <t> In the case of NAPT (m:1), the address will be the security
+        gateway itself. The ability to get
+        KEY and TXT records in place will again depend upon whether or not
+	there is administrative control over the reverse-map. This is
+	identical to situations involving a single host acting on behalf of
+	itself. 
+
+	FQDN style can be used to get around a lack of a reverse-map for
+	initiators only.
+    </t>
+  </section>
+
+  <section title="Security Gateway behind NAT/NAPT">
+    <t>
+       If there is a NAT or NAPT between the security gateways, then normal IPsec
+       NAT traversal problems occur. In addition to the transport problem
+       which may be solved by other mechanisms, there is the issue of
+       what phase 1 and phase 2 IDs to use. While FQDN could
+       be used during phase 1 for the security gateway, there is no appropriate ID for phase 2.
+       Due to the NAT, the end systems live in different IP address spaces.
+    </t>
+  </section>
+
+  <section title="End System is behind a NAT/NAPT">
+    <t>
+       If the end system is behind a NAT (perhaps SG-B), then there is, in fact, no way for
+       another end system to address a packet to this end system.
+       Not only is opportunistic encryption
+       impossible, but it is also impossible for any communication to
+       be initiate to the end system. It may be possible for this end
+       system to initiate in such communication. This creates an asymmetry, but this is common for 
+       NAPT.
+    </t>
+  </section>
+</section>
+
+<section title="Host implementations">
+<t>
+  When Alice and SG-A are components of the same system, they are
+  considered to be a host implementation. The packet sequence scenario remains unchanged.
+</t>
+<t>
+  Components marked Alice are the upper layers (TCP, UDP, the
+  application), and SG-A is the IP layer.
+</t>
+<t>
+  Note that tunnel mode is still required. 
+</t>
+<t>
+  As Alice and SG-A are acting on behalf of themselves, no TXT based delegation
+  record is necessary for Alice to initiate. She can rely on FQDN in a
+  forward map. This is particularly attractive to mobile nodes such as 
+  notebook computers at conferences.
+  To respond, Alice/SG-A will still need an entry in Alice's reverse-map.
+</t>
+</section>
+
+<section title="Multi-homing">
+<t> 
+If there are multiple paths between Alice and Bob (as illustrated in
+the diagram with SG-D), then additional DNS records are required to establish
+authorization. 
+</t>
+<t>
+In <xref target="networkdiagram" />, Alice has two ways to
+exit her network: SG-A and SG-D. Previously SG-D has been ignored. Postulate
+that there are routers between Alice and her set of security gateways
+(denoted by the + signs and the marking of an autonomous system number for
+Alice's network). Datagrams may, therefore, travel to either SG-A or SG-D en
+route to Bob.
+</t>
+<t>
+As long as all network connections are in good order, it does not matter how
+datagrams exit Alice's network. When they reach either security gateway, the
+security gateway will find the TXT delegation record in Bob's reverse-map,
+and establish an SA with SG-B. 
+</t>
+<t>
+SG-B has no problem establishing that either of SG-A or SG-D may speak for
+Alice, because Alice has published two equally weighted TXT delegation records:
+    <figure anchor="txtmultiexample"
+    title="Multiple gateway delegation example for Alice">
+           <artwork><![CDATA[
+X-IPsec-Server(10)=192.1.1.5 AQMM...3s1Q==
+X-IPsec-Server(10)=192.1.1.6 AAJN...j8r9==
+          ]]></artwork>
+    </figure>
+</t>
+<t>
+Alice's routers can now do any kind of load sharing needed. Both SG-A and SG-D send datagrams addressed to Bob through
+their tunnel to SG-B. 
+</t>
+<t>
+Alice's use of non-equal weight delegation records to show preference of one gateway over another, has relevance only when SG-B 
+is initiating to Alice. 
+</t>
+<t>
+If the precedences are the same, then SG-B has a more difficult time. It
+must decide which of the two tunnels to use. SG-B has no information about
+which link is less loaded, nor which security gateway has more cryptographic
+resources available. SG-B, in fact, has no knowledge of whether both gateways
+are even reachable.  
+</t>
+<t>
+The Public Internet's default-free zone may well know a good route to Alice,
+but the datagrams that SG-B creates must be addressed to either SG-A or SG-D;
+they can not be addressed to Alice directly.
+</t>
+<t>
+SG-B may make a number of choices:
+<list style="numbers">
+<t>It can ignore the problem and round robin among the tunnels. This
+      causes losses during times when one or the other security gateway is
+      unreachable. If this worries Alice, she can change the weights in her
+      TXT delegation records.</t>
+
+<t>It can send to the gateway from which it most recently received datagrams. 
+      This assumes that routing and reachability are symmetrical.</t>
+
+<t>It can listen to BGP information from the Internet to decide which
+      system is currently up. This is clearly much more complicated, but if SG-B is already participating
+      in the BGP peering system to announce Bob, the results data may already
+      be available to it. </t>
+
+<t>It can refuse to negotiate the second tunnel. (It is unclear whether or
+not this is even an option.)</t>
+
+<t>It can silently replace the outgoing portion of the first tunnel with the
+second one while still retaining the incoming portions of both. SG-B can,
+thus, accept datagrams from either SG-A or SG-D, but
+send only to the gateway that most recently re-keyed with it.</t> 
+</list>
+</t>
+
+<t>
+Local policy determines which choice SG-B makes. Note that even if SG-B has perfect
+knowledge about the reachability of SG-A and SG-D, Alice may not be reachable
+from either of these security gateways because of internal reachability
+issues. 
+</t>
+
+<t>
+FreeS/WAN implements option 5.  Implementing a different option is
+being considered. The multi-homing aspects of OE are not well developed and may
+be the subject of a future document.
+</t>
+	
+</section>
+
+<section title="Failure modes">
+  <section title="DNS failures">
+  <t>
+  If a DNS server fails to respond, local policy decides
+  whether or not to permit communication in the clear as embodied in
+  the connection classes in <xref target="initclasses" />.
+  It is easy to mount a denial of service attack on the DNS server
+  responsible for a particular network's reverse-map.
+  Such an attack may cause all communication with that network to go in
+  the clear if the policy is permissive, or fail completely 
+  if the policy is paranoid. Please note that this is an active attack.
+  </t>
+  <t>
+  There are still many networks
+  that do not have properly configured reverse-maps. Further, if the policy is not to communicate,
+  the above denial of service attack isolates the target network. Therefore, the decision of whether 
+or not to permit communication in the clear MUST be a matter of local policy.
+  </t>
+  </section>
+
+  <section title="DNS configured, IKE failures">
+  <t>
+  DNS records claim that opportunistic encryption should
+  occur, but the target gateway either does not respond on port 500, or
+  refuses the proposal. This may be because of a crash or reboot, a
+  faulty configuration, or a firewall filtering port 500.  
+  </t>
+  <t>
+  The receipt of ICMP port, host or network unreachable
+  messages indicates a potential problem, but MUST NOT cause communication
+  to fail 
+  immediately. ICMP messages are easily forged by attackers. If such a
+  forgery caused immediate failure, then an active attacker could easily
+  prevent any 
+  encryption from ever occurring, possibly preventing all communication.
+  </t>
+  <t>
+  In these situations a clear log should be produced
+  and local policy should dictate if communication is then
+  permitted in the clear.
+  </t>
+  </section>
+
+  <section title="System reboots">
+<t>
+Tunnels sometimes go down because the remote end crashes,
+disconnects, or has a network link break.  In general there is no
+notification of this.  Even in the event of a crash and successful reboot, 
+other SGs don't hear about it unless the rebooted SG has specific 
+reason to talk to them immediately.  Over-quick response to temporary 
+network outages is undesirable.  Note that a tunnel can be torn
+down and then re-established without any effect visible to the user
+except a pause in traffic. On the other hand, if one end reboots,
+the other end can't get datagrams to it at all (except via
+IKE) until the situation is noticed.  So a bias toward quick
+response is appropriate even at the cost of occasional
+false alarms.
+</t>
+
+<t>
+A mechanism for recovery after reboot is a topic of current research and is not specified in this
+document.
+</t>
+
+<t>
+A deliberate shutdown should include an attempt, using deletes, to notify all other SGs
+currently connected by phase 1 SAs that communication is
+about to fail.  Again, a remote SG will assume this is a teardown.  Attempts by the
+remote SGs to negotiate new tunnels as replacements should be ignored. When possible, 
+SGs should attempt to preserve information about currently-connected SGs in non-volatile storage, so
+that after a crash, an Initial-Contact can be sent to previous partners to
+indicate loss of all previously established connections.
+</t>
+
+  </section>
+</section>
+
+<!--
+<section title="Performance experiences">
+
+    Claudia> Is it useful to point out (or to clarify for our own discussion) any of the
+    Claudia> following:
+
+    Claudia> *  how much time this is likely to take on typical current hardware?
+    Claudia> *  what steps are likely to be time consuming
+    Claudia> *  how any added time could affect a typical transaction, such as hitting 
+    Claudia>    a web site
+    Claudia> *  any ways to minimize such time delays
+
+  <section title="Introduced latency">
+  </section>
+
+  <section title="Cryptographic performance">
+  </section>
+
+  <section title="Phase 1 SA performance">
+  </section>
+
+</section>
+-->
+
+<section title="Unresolved issues">
+  <section title="Control of reverse DNS">
+  <t>
+  The method of obtaining information by reverse DNS lookup causes
+  problems for people who cannot control their reverse DNS
+  bindings. This is an unresolved problem in this version, and is out
+  of scope.
+  </t>
+  </section>
+</section>
+
+<section title="Examples">
+
+<section title="Clear-text usage (permit policy)">
+
+<t>
+Two example scenarios follow. In the first example GW-A
+(Gateway A) and GW-B (Gateway B) have always-clear-text policies, and in the second example they have an OE
+policy. The clear-text policy serves as a reference for what occurs in
+TCP/IP in the absence of Opportunistic Encryption.
+
+<t>
+Alice wants to communicate with Bob. Perhaps she wants to retrieve a
+web page from Bob's web server. In the absence of opportunistic
+encryptors, the following events occur: 
+</t>
+
+       <figure anchor="regulartiming" title="Timing of regular transaction">
+           <artwork><![CDATA[
+  Alice         SG-A       DNS       SG-B           Bob
+   Human or application
+   'clicks' with a name.
+   (1)
+
+    ------(2)-------------->
+    Application looks up
+    name in DNS to get
+    IP address.
+
+    <-----(3)---------------
+    Resolver returns "A" RR
+    to application with IP 
+    address.
+
+   (4)
+   Application starts a TCP session
+   or UDP session and OS sends
+   first datagram
+
+       ----(5)----->
+       Datagram is seen at first gateway
+       from Alice (SG-A). 
+
+                   ----------(6)------>
+                   Datagram traverses
+                   network.
+
+                                       ------(7)----->
+                                       Datagram arrives
+                                       at Bob, is provided
+                                       to TCP.
+
+                                      <------(8)------
+                                       A reply is sent.
+
+                   <----------(9)------
+                   Datagram traverses
+                   network.
+    <----(10)-----
+    Alice receives
+    answer.
+
+   (11)----------->
+    A second exchange
+    occurs.
+                   ----------(12)----->
+                                       -------------->
+                                      <---------------
+                   <-------------------
+    <-------------
+          ]]></artwork>
+</figure>
+
+</t>
+</section>
+
+<section title="Opportunistic encryption">
+
+<t>
+In the presence of properly configured opportunistic encryptors, the
+event list is extended. Only changes are annotated.
+</t>
+
+<t>The following symbols are used in the time-sequence diagram</t>
+
+<t>
+<list style="hanging">
+    <t hangText="-"> A single dash represents clear-text datagrams.</t>
+    <t hangText="="> An equals sign represents phase 2 (IPsec) cipher-text
+        datagrams.</t> 
+    <t hangText="~"> A single tilde represents clear-text phase 1 datagrams.</t>
+    <t hangText="#"> A hash sign represents phase 1 (IKE) cipher-text
+        datagrams.</t> 
+</list>
+</t>
+
+<t>
+<figure anchor="opportunistictiming" title="Timing of opportunistic encryption transaction">
+           <artwork><![CDATA[
+  Alice          SG-A      DNS       SG-B           Bob
+   (1)
+    ------(2)-------------->
+    <-----(3)---------------
+   (4)----(5)----->+
+      SG-A sees datagram 
+      to new target and
+      saves it as "first"
+
+                  ----(5B)->
+                  SG-A asks DNS 
+                  for TXT RR.
+
+                  <---(5C)--
+                  DNS returns TXT RR.
+
+                  ~~~~~~~~~~~~~(5D)~~~>
+                  initial IKE main mode 
+                  packet is sent.       
+
+                  <~~~~~~~~~~~~(5E1)~~~
+                  ~~~~~~~~~~~~~(5E2)~~>
+                  <~~~~~~~~~~~~(5E3)~~~
+                  IKE phase 1 - privacy.
+
+                  #############(5E4)##>
+                  SG-A sends ID to SG-B
+                           <----(5F1)--
+                            SG-B asks DNS
+                            for SG-A's public 
+                            KEY
+                           -----(5F2)->
+                            DNS provides KEY RR.
+                            SG-B authenticates SG-A
+
+                  <############(5E5)###
+                  IKE phase 1 - complete
+                           
+                  #############(5G1)##>
+                  IKE phase 2 - Alice<->Bob
+                  tunnel is proposed.
+
+                           <----(5H1)--
+                            SG-B asks DNS for
+                            Alice's TXT record.
+                           -----(5H2)->
+                            DNS replies with TXT
+                            record. SG-B checks
+                            SG-A's authorization.
+
+                  <############(5G2)###
+                   SG-B accepts proposal.
+
+                  #############(5G3)##>
+                   SG-A confirms.
+
+                   ============(6)====>
+                    SG-A sends "first"
+                    packet in new IPsec
+                    SA.
+                                       ------(7)----->
+                                        packet is decrypted
+                                        and forward to Bob.
+                                      <------(8)------
+                  <==========(9)======
+                    return packet also
+                    encrypted.
+    <-----(10)----
+
+   (11)----------->
+     a second packet
+     is sent by Alice
+                   ==========(12)=====>
+                    existing tunnel is used
+                                       -------------->
+                                      <---------------
+                   <===================
+    <-------------
+          ]]></artwork>
+</figure>
+
+</t>
+
+  <t>
+  For the purposes of this section, we will describe only the changes that
+  occur between <xref target="regulartiming" /> and
+  <xref target="opportunistictiming" />. This corresponds to time points 5, 6, 7, 9 and 10 on the list above. 
+  </t>
+
+<list style="symbols">
+  <t>
+    At point (5), SG-A intercepts the datagram because this source/destination pair lacks a policy 
+(the non-existent policy state). SG-A creates a hold policy, and buffers the datagram. SG-A requests keys from the keying daemon. 
+    </t>
+
+    <t>
+    SG-A's IKE daemon, having looked up the source/destination pair in the connection
+    class list, creates a new Potential OE connection instance. SG-A starts DNS
+    queries.
+    </t>
+  </section>
+
+  <section title="(5C) DNS returns TXT record(s)">
+
+  <t>
+  DNS returns properly formed TXT delegation records, and SG-A's IKE daemon
+  causes this instance to make a transition from Potential OE connection to Pending OE
+  connection.
+  </t>
+
+    <t>
+      Using the example above, the returned record might contain:
+
+    <figure anchor="txtexample"
+    title="Example of reverse delegation record for Bob">
+           <artwork><![CDATA[
+X-IPsec-Server(10)=192.1.1.5 AQMM...3s1Q==
+          ]]></artwork>
+    </figure>
+    with SG-B's IP address and public key listed.
+    </t>
+
+  </section>
+
+  <section title="(5D) Initial IKE main mode packet goes out">
+  <t>Upon entering Pending OE connection, SG-A sends the initial ISAKMP
+  message with proposals. See <xref target="phase1id" />.
+  </t>
+  </section>
+
+  <section title="(5E1) Message 2 of phase 1 exchange">
+  <t>
+  SG-B receives the message. A new connection instance is created in the
+  unauthenticated OE peer state.
+  </t>
+  </section>
+
+  <section title="(5E2) Message 3 of phase 1 exchange">
+  <t>
+  SG-A sends a Diffie-Hellman exponent. This is an internal state of the
+  keying daemon.
+  </t>
+  </section>
+
+  <section title="(5E3) Message 4 of phase 1 exchange">
+  <t>
+  SG-B responds with a Diffie-Hellman exponent. This is an internal state of the
+  keying protocol.
+  </t>
+  </section>
+
+  <section title="(5E4) Message 5 of phase 1 exchange">
+  <t>
+  SG-A uses the phase 1 SA to send its identity under encryption. 
+  The choice of identity is discussed in <xref target="phase1id" />.
+  This is an internal state of the keying protocol.
+  </t>
+  </section>
+
+  <section title="(5F1) Responder lookup of initiator key">
+  <t>
+  SG-B asks DNS for the public key of the initiator. 
+  DNS looks for a KEY record by IP address in the reverse-map.
+  That is, a KEY resource record is queried for 4.1.1.192.in-addr.arpa
+  (recall that SG-A's external address is 192.1.1.4).
+  SG-B uses the resulting public key to authenticate the initiator. See <xref
+  target="KEY" /> for further details. 
+  </t>
+  </section>
+
+<section title="(5F2) DNS replies with public key of initiator">
+<t>
+Upon successfully authenticating the peer, the connection instance makes a
+transition to authenticated OE peer on SG-B.
+</t>
+<t>
+The format of the TXT record returned is described in
+<xref target="TXT" />. 
+</t>
+</section>
+
+  <section title="(5E5) Responder replies with ID and authentication">
+  <t>
+    SG-B sends its ID along with authentication material. This is an internal
+    state for the keying protocol.
+  </t>
+  </section>
+
+  <section title="(5G) IKE phase 2">
+    <section title="(5G1) Initiator proposes tunnel">
+    <t>
+    Having established mutually agreeable authentications (via KEY) and
+    authorizations (via TXT), SG-A proposes to create an IPsec tunnel for
+    datagrams transiting from Alice to Bob. This tunnel is established only for 
+    the Alice/Bob combination, not for any subnets that may be behind SG-A and SG-B.
+    </t>
+    </section>
+
+    <section title="(5H1) Responder determines initiator's authority">
+    <t>
+    While the identity of SG-A has been established, its authority to
+    speak for Alice has not yet been confirmed. SG-B does a reverse
+    lookup on Alice's address for a TXT record. 
+    </t>
+    <t>Upon receiving this specific proposal, SG-B's connection instance
+    makes a transition into the potential OE connection state. SG-B may already have an
+    instance, and the check is made as described above.</t>
+    </section>
+  
+    <section title="(5H2) DNS replies with TXT record(s)">
+    <t>
+      The returned key and IP address should match that of SG-A.
+    </t>	
+    </section>
+    
+    <section title="(5G2) Responder agrees to proposal">
+    <t>
+    Should additional communication occur between, for instance, Dave and Bob using
+    SG-A and SG-B, a new tunnel (phase 2 SA) would be established. The phase 1 SA
+    may be reusable.
+    </t>
+    <t>SG-A, having successfully keyed the tunnel, now makes a transition from
+    Pending OE connection to Keyed OE connection.
+    </t>
+    <t>The responder MUST setup the inbound IPsec SAs before sending its reply.</t>
+    </section>
+
+    <section title="(5G3) Final acknowledgment from initiator">
+    <t>
+    The initiator agrees with the responder's choice and sets up the tunnel.
+    The initiator sets up the inbound and outbound IPsec SAs.
+    </t>
+    <t>
+    The proper authorization returned with keys prompts SG-B to make a transition
+    to the keyed OE connection state. 
+    </t>
+    <t>Upon receipt of this message, the responder may now setup the outbound
+    IPsec SAs.</t> 
+    </section>
+  </section>
+
+  <section title="(6) IPsec succeeds, and sets up tunnel for communication between Alice and Bob">
+  <t>
+  SG-A sends the datagram saved at step (5) through the newly created
+  tunnel to SG-B, where it gets decrypted and forwarded. 
+  Bob receives it at (7) and replies at (8). 
+  </t>
+  </section>
+
+  <section title="(9) SG-B already has tunnel up with G1 and uses it">
+  <t>
+  At (9), SG-B has already established an SPD entry mapping Bob->Alice via a
+  tunnel, so this tunnel is simply applied. The datagram is encrypted to SG-A,
+  decrypted by SG-A and passed to Alice at (10).
+  </t>
+
+  </section>
+</section> <!-- OE example -->
+
+</section> <!-- Examples -->
+
+<section anchor="securityconsiderations" title="Security considerations">
+
+  <section title="Configured vs opportunistic tunnels">
+<t>
+    Configured tunnels are those which are setup using bilateral mechanisms: exchanging 
+public keys (raw RSA, DSA, PKIX), pre-shared secrets, or by referencing keys that
+are in known places (distinguished name from LDAP, DNS). These keys are then used to
+configure a specific tunnel. 
+</t>
+<t>
+A pre-configured tunnel may be on all the time, or may be keyed only when needed. 
+The end points of the tunnel are not necessarily static: many mobile
+applications (road warrior) are considered to be configured tunnels. 
+</t>
+<t>
+The primary characteristic is that configured tunnels are assigned specific
+security properties. They may be trusted in different ways relating to exceptions to 
+firewall rules, exceptions to NAT processing, and to bandwidth or other quality of service restrictions. 
+</t>
+<t>
+Opportunistic tunnels are not inherently trusted in any strong way. They are
+created without prior arrangement. As the two parties are strangers, there
+MUST be no confusion of datagrams that arrive from opportunistic peers and
+those that arrive from configured tunnels. A security gateway MUST take care
+that an opportunistic peer can not impersonate a configured peer.
+</t>
+<t>
+Ingress filtering MUST be used to make sure that only datagrams authorized by
+negotiation (and the concomitant authentication and authorization) are
+accepted from a tunnel. This is to prevent one peer from impersonating another. 
+</t>
+<t>
+An implementation suggestion is to treat opportunistic tunnel
+datagrams as if they arrive on a logical interface distinct from other
+configured tunnels. As the number of opportunistic tunnels that may be
+created automatically on a system is potentially very high, careful attention 
+to scaling should be taken into account.
+</t>
+<t>
+As with any IKE negotiation, opportunistic encryption cannot be secure
+without authentication. Opportunistic encryption relies on DNS for its
+authentication information and, therefore, cannot be fully secure without
+a secure DNS. Without secure DNS, opportunistic encryption can protect against passive
+eavesdropping but not against active man-in-the-middle attacks.
+</t>
+  </section>
+
+  <section title="Firewalls versus Opportunistic Tunnels">
+<t>
+  Typical usage of per datagram access control lists is to implement various
+kinds of security gateways. These are typically called "firewalls". 
+</t>
+<t>
+  Typical usage of a virtual private network (VPN) within a firewall is to
+bypass all or part of the access controls between two networks. Additional
+trust (as outlined in the previous section) is given to datagrams that arrive
+in the VPN.
+</t>
+<t> 
+  Datagrams that arrive via opportunistically configured tunnels MUST not be
+trusted. Any security policy that would apply to a datagram arriving in the
+clear SHOULD also be applied to datagrams arriving opportunistically.
+</t>
+  </section>
+
+  <section title="Denial of service">
+<t>
+  There are several different forms of denial of service that an implementor 
+  should concern themselves with. Most of these problems are shared with
+  security gateways that have large numbers of mobile peers (road warriors). 
+</t>
+<t>
+  The design of ISAKMP/IKE, and its use of cookies, defend against many kinds
+  of denial of service. Opportunism changes the assumption that if the phase 1 (ISAKMP) 
+  SA is authenticated, that it was worthwhile creating. Because the gateway will communicate with any machine, it is
+  possible to form phase 1 SAs with any machine on the Internet. 
+</t>
+
+</section>
+</section>
+
+<section title="IANA Considerations">
+<t>
+    There are no known numbers which IANA will need to manage.
+</t>
+</section>
+
+<section title="Acknowledgments">
+<t>
+        Substantive portions of this document are based upon previous work by
+        Henry Spencer.
+</t>
+<t>
+	Thanks to Tero Kivinen, Sandy Harris, Wes Hardarker, Robert Moskowitz,
+	Jakob Schlyter, Bill Sommerfeld, John Gilmore and John Denker for their
+	comments and constructive criticism.
+</t>
+<t>
+	Sandra Hoffman and Bill Dickie did the detailed proof reading and editing.
+</t>
+</section>
+
+</middle>
+
+<back>
+<references title="Normative references">
+<?rfc include="reference.OEspec" ?>
+<!-- renumber according to reference order -->
+<?rfc include="reference.RFC.0791" ?>
+<?rfc include="reference.RFC.1009" ?>
+<?rfc include="reference.RFC.1984" ?>
+<?rfc include="reference.RFC.2119" ?>
+<!-- IPsec -->
+<?rfc include="reference.RFC.2367" ?>
+<?rfc include="reference.RFC.2401" ?>
+<?rfc include="reference.RFC.2407" ?>
+<?rfc include="reference.RFC.2408" ?>
+<?rfc include="reference.RFC.2409" ?>
+<!-- MODPGROUPS -->
+<?rfc include="reference.RFC.3526" ?>
+<!-- DNSSEC -->
+<?rfc include="reference.RFC.1034" ?>
+<?rfc include="reference.RFC.1035" ?>
+<?rfc include="reference.RFC.2671" ?>
+<?rfc include="reference.RFC.1464" ?>
+<?rfc include="reference.RFC.2535" ?>
+<?rfc include="reference.RFC.3110" ?>
+<?rfc include="reference.RFC.2538" ?>
+<!-- COPS -->
+<?rfc include="reference.RFC.2748" ?>
+<!-- NAT -->
+<?rfc include="reference.RFC.2663" ?>
+</references>
+<!-- <references title="Non-normative references"> -->
+<!-- ESPUDP -->
+<!-- <?rfc include="reference.ESPUDP" ?> -->
+<!-- </references> -->
+</back>
+</rfc>
+<!--
+  $Id: draft-richardson-ipsec-opportunistic.xml,v 1.1 2004/03/15 20:35:24 as Exp $
+
+  $Log: draft-richardson-ipsec-opportunistic.xml,v $
+  Revision 1.1  2004/03/15 20:35:24  as
+  added files from freeswan-2.04-x509-1.5.3
+
+  Revision 1.33  2003/06/30 03:19:59  mcr
+  	timing-diagram with inline explanation.
+
+  Revision 1.32  2003/06/30 01:57:44  mcr
+  	initial edits per-Bob Braden.
+
+  Revision 1.31  2003/05/26 19:31:23  mcr
+  	updates to drafts - IPSEC RR - SC versions, and RFC3526
+  	reference in OE draft.
+
+  Revision 1.30  2003/05/21 15:42:34  mcr
+  	updates due to publication of RFC 3526.
+
+  Revision 1.29  2003/01/17 16:22:55  mcr
+  	rev 11 of OE draft.
+
+  Revision 1.28  2002/07/25 19:27:31  mcr
+  	added DHR's minor edits.
+
+  Revision 1.27  2002/07/21 16:26:26  mcr
+  	slides from presentation at OLS
+  	draft-10 of OE draft.
+
+  Revision 1.26  2002/07/16 03:46:53  mcr
+  	second edits from Sandra.
+
+  Revision 1.25  2002/07/16 03:36:14  mcr
+  	removed HS from authors list
+  	updated reference inclusion to use <?rfc-include directive.
+  Revision 1.24  2002/07/11 02:08:21  mcr
+  	updated XML file from Sandra
+
+  Revision 1.23  2002/06/06 17:18:53  mcr
+  	spellcheck.
+
+  Revision 1.22  2002/06/06 17:14:19  mcr
+  	results of hand-editing session from May 28th.
+  	This is FINAL OE draft.
+
+  Revision 1.21  2002/06/06 02:25:44  mcr
+  	results of hand-editing session from May 28th.
+  	This is FINAL OE draft.
+
+  Revision 1.20  2002/05/24 03:28:37  mcr
+  	changes as requested by RFC editor.
+
+  Revision 1.19  2002/04/09 16:01:05  mcr
+  	comments from PHB.
+
+  Revision 1.18  2002/04/08 02:14:34  mcr
+  	RGBs changes to rev6.
+
+  Revision 1.17  2002/03/12 21:23:55  mcr
+  	adjusted definition of default-free zone.
+  	moved text on key rollover from format description to new
+  	section.
+
+  Revision 1.16  2002/02/22 01:23:21  mcr
+  	revisions from MCR (2002/2/18) and net.
+
+  Revision 1.15  2002/02/21 20:44:12  mcr
+  	extensive from DHR.
+
+  Revision 1.14  2002/02/10 16:20:39  mcr
+  	-05 draft. Many revisions to do "OE system in world of OE systems"
+  	view of the universe.
+
+  Revision 1.13  2001/12/20 04:35:22  mcr
+  	fixed reference to rfc1984.
+
+  Revision 1.12  2001/12/20 03:35:19  mcr
+  	comments from Henry, Tero, and Sandy.
+
+  Revision 1.11  2001/12/19 07:26:22  mcr
+  	added comment about KX records.
+
+  Revision 1.10  2001/11/09 04:28:10  mcr
+  	fixed some typos with XML, and one s/SG-B/SG-D/.
+
+  Revision 1.9  2001/11/09 04:07:13  mcr
+  	expanded section 10: multihoming, with an example.
+
+  Revision 1.8  2001/11/09 02:16:51  mcr
+  	added lifetime/lifespan definitions.
+  	moved example from 5B to 5C.
+  	added reference to phase 1 IDs to 5D.
+  	cleared up text in aging section.
+  	added text about delegation of DNSSEC activity to a DNS server.
+  	spelt out DH group names.
+  	added text about ignoring TXT records unless DNSSEC is deployed (somerfeld)
+  	added example of TXT delegation using FQDN.
+  	clarified some text in NAT interaction section.
+  	clarified absense of TXT record need for host implementation
+
+  Revision 1.7  2001/11/08 23:09:37  mcr
+  	changed revision of draft to 03.
+
+  Revision 1.6  2001/11/08 19:37:14  mcr
+  	fixed some formatting of Aging section.
+
+  Revision 1.5  2001/11/08 19:19:30  mcr
+  	fixed address for DHR, updated address for MCR,
+  	added reference to original HS/DHR OE specification paper.
+
+  Revision 1.4  2001/11/08 19:08:24  mcr
+  	section 10, "Renewal and Teardown" added moved between 4/5, and
+  	slightly rewritten.
+
+  Revision 1.3  2001/11/08 18:56:34  mcr
+  	sections 4.2, 5.6, 5.7.1 and 6.2 edited as per HS.
+  	section 10, "Renewal and Teardown" added.
+  	section 11, "Failure modes" completed.
+
+  Revision 1.2  2001/11/05 20:31:31  mcr
+  	added section from OE spec on aging and teardown.
+
+  Revision 1.1  2001/11/05 04:27:58  mcr
+  	OE draft added to documentation.
+
+  Revision 1.12  2001/10/10 01:12:31  mcr
+  	removed impact on DNS servers section.
+  	removed nested comments.
+  	adjusted data of issue
+
+  Revision 1.11  2001/09/17 02:55:50  mcr
+  	outline is now stable.
+
+  Revision 1.5  2001/08/19 02:53:32  mcr
+  	version 00d formatted.
+
+  Revision 1.10  2001/08/19 02:34:04  mcr
+  	version 00d formatted.
+
+  Revision 1.9  2001/08/19 02:21:54  mcr
+  	version 00d
+
+  Revision 1.8  2001/07/20 19:07:06  mcr
+    commented out section 1.1
+
+  Revision 1.7  2001/07/20 14:14:22  mcr
+  	HS and HD comments.
+
+  Revision 1.6  2001/07/19 00:56:50  mcr
+  	version 00b.
+
+  Revision 1.5  2001/07/12 23:57:07  mcr
+  	OE ID, 00.
+
+
+!>
diff --git a/doc/src/draft-richardson-ipsec-rr.html b/doc/src/draft-richardson-ipsec-rr.html
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+<html><head><title>A method for storing IPsec keying material in DNS.</title>
+<STYLE type='text/css'>
+    .title { color: #990000; font-size: 22px; line-height: 22px; font-weight: bold; text-align: right;
+             font-family: helvetica, arial, sans-serif }
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+    li { margin-left: 3em;  }
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+    ul.text { margin-left: 2em; margin-right: 2em; }
+    pre { margin-left: 3em; color: #333333 }
+    ul.toc { color: #000000; line-height: 16px;
+             font-family: verdana, charcoal, helvetica, arial, sans-serif }
+    H3 { color: #333333; font-size: 16px; line-height: 16px; font-family: helvetica, arial, sans-serif }
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+                     font-family: verdana, charcoal, helvetica, arial, sans-serif }
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+             font-family: monaco, charcoal, geneva, MS Sans Serif, helvetica, monotype, verdana, sans-serif;
+             font-size: 9px }
+    .RFC { color:#666666; font-weight: bold; text-decoration: none;
+           font-family: monaco, charcoal, geneva, MS Sans Serif, helvetica, monotype, verdana, sans-serif;
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+               font-family: charcoal, monaco, geneva, MS Sans Serif, helvetica, monotype, verdana, sans-serif;
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+</style>
+</head>
+<body bgcolor="#ffffff" text="#000000" alink="#000000" vlink="#666666" link="#990000">
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<table width="66%" border="0" cellpadding="0" cellspacing="0"><tr><td><table width="100%" border="0" cellpadding="2" cellspacing="1">
+<tr valign="top"><td width="33%" bgcolor="#666666" class="header">IPSECKEY WG</td><td width="33%" bgcolor="#666666" class="header">M. Richardson</td></tr>
+<tr valign="top"><td width="33%" bgcolor="#666666" class="header">Internet-Draft</td><td width="33%" bgcolor="#666666" class="header">SSW</td></tr>
+<tr valign="top"><td width="33%" bgcolor="#666666" class="header">Expires: March 4, 2004</td><td width="33%" bgcolor="#666666" class="header">September 4, 2003</td></tr>
+</table></td></tr></table>
+<div align="right"><font face="monaco, MS Sans Serif" color="#990000" size="+3"><b><br><span class="title">A method for storing IPsec keying material in DNS.</span></b></font></div>
+<div align="right"><font face="monaco, MS Sans Serif" color="#666666" size="+2"><b><span class="filename">draft-ietf-ipseckey-rr-07.txt</span></b></font></div>
+<font face="verdana, helvetica, arial, sans-serif" size="2">
+
+<h3>Status of this Memo</h3>
+<p>
+This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026.</p>
+<p>
+Internet-Drafts are working documents of the Internet Engineering
+Task Force (IETF), its areas, and its working groups.
+Note that other groups may also distribute working documents as
+Internet-Drafts.</p>
+<p>
+Internet-Drafts are draft documents valid for a maximum of six months
+and may be updated, replaced, or obsoleted by other documents at any time.
+It is inappropriate to use Internet-Drafts as reference material or to cite
+them other than as "work in progress."</p>
+<p>
+The list of current Internet-Drafts can be accessed at
+<a href='http://www.ietf.org/ietf/1id-abstracts.txt'>http://www.ietf.org/ietf/1id-abstracts.txt</a>.</p>
+<p>
+The list of Internet-Draft Shadow Directories can be accessed at
+<a href='http://www.ietf.org/shadow.html'>http://www.ietf.org/shadow.html</a>.</p>
+<p>
+This Internet-Draft will expire on March 4, 2004.</p>
+
+<h3>Copyright Notice</h3>
+<p>
+Copyright (C) The Internet Society (2003). All Rights Reserved.</p>
+
+<h3>Abstract</h3>
+
+<p>
+This document describes a new resource record for DNS. This record may be
+used to store public keys for use in IPsec systems. 
+
+</p>
+<p>
+This record replaces the functionality of the sub-type #1 of the KEY Resource
+Record, which has been obsoleted by RFC3445.
+
+</p><a name="toc"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<h3>Table of Contents</h3>
+<ul compact class="toc">
+<b><a href="#anchor1">1.</a>&nbsp;
+Introduction<br></b>
+<b><a href="#anchor2">1.1</a>&nbsp;
+Overview<br></b>
+<b><a href="#anchor3">1.2</a>&nbsp;
+Usage Criteria<br></b>
+<b><a href="#anchor4">2.</a>&nbsp;
+Storage formats<br></b>
+<b><a href="#anchor5">2.1</a>&nbsp;
+IPSECKEY RDATA format<br></b>
+<b><a href="#anchor6">2.2</a>&nbsp;
+RDATA format - precedence<br></b>
+<b><a href="#algotype">2.3</a>&nbsp;
+RDATA format - algorithm type<br></b>
+<b><a href="#gatewaytype">2.4</a>&nbsp;
+RDATA format - gateway type<br></b>
+<b><a href="#anchor7">2.5</a>&nbsp;
+RDATA format - gateway<br></b>
+<b><a href="#anchor8">2.6</a>&nbsp;
+RDATA format - public keys<br></b>
+<b><a href="#anchor9">3.</a>&nbsp;
+Presentation formats<br></b>
+<b><a href="#anchor10">3.1</a>&nbsp;
+Representation of IPSECKEY RRs<br></b>
+<b><a href="#anchor11">3.2</a>&nbsp;
+Examples<br></b>
+<b><a href="#anchor12">4.</a>&nbsp;
+Security Considerations<br></b>
+<b><a href="#anchor13">4.1</a>&nbsp;
+Active attacks against unsecured IPSECKEY resource records<br></b>
+<b><a href="#anchor14">5.</a>&nbsp;
+IANA Considerations<br></b>
+<b><a href="#anchor15">6.</a>&nbsp;
+Acknowledgments<br></b>
+<b><a href="#rfc.references1">&#167;</a>&nbsp;
+Normative references<br></b>
+<b><a href="#rfc.references2">&#167;</a>&nbsp;
+Non-normative references<br></b>
+<b><a href="#rfc.authors">&#167;</a>&nbsp;
+Author's Address<br></b>
+<b><a href="#rfc.copyright">&#167;</a>&nbsp;
+Full Copyright Statement<br></b>
+</ul>
+<br clear="all">
+
+<a name="anchor1"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<a name="rfc.section.1"></a><h3>1.&nbsp;Introduction</h3>
+
+<p>
+   The type number for the IPSECKEY RR is TBD.
+
+</p>
+<a name="rfc.section.1.1"></a><h4><a name="anchor2">1.1</a>&nbsp;Overview</h4>
+
+<p>
+   The IPSECKEY resource record (RR) is used to publish a public key that is
+   to be associated with a Domain Name System (DNS) name for use with the
+   IPsec protocol suite.  This can be the  public key of a host,
+   network, or application (in the case of per-port keying).
+
+</p>
+<p>
+      The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
+      NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and
+      "OPTIONAL" in this document are to be interpreted as described in
+      RFC2119 <a href="#RFC2119">[8]</a>.
+
+</p>
+<a name="rfc.section.1.2"></a><h4><a name="anchor3">1.2</a>&nbsp;Usage Criteria</h4>
+
+<p>
+   An IPSECKEY resource record SHOULD be used in combination with DNSSEC
+unless some other means of authenticating the IPSECKEY resource record
+is available.
+
+</p>
+<p>  
+   It is expected that there will often be multiple IPSECKEY resource
+   records at the same name. This will be due to the presence
+   of multiple gateways and the need to rollover keys.
+
+
+</p>
+<p>
+   This resource record is class independent.
+
+</p>
+<a name="anchor4"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<a name="rfc.section.2"></a><h3>2.&nbsp;Storage formats</h3>
+
+<a name="rfc.section.2.1"></a><h4><a name="anchor5">2.1</a>&nbsp;IPSECKEY RDATA format</h4>
+
+<p>
+   The RDATA for an IPSECKEY RR consists of a precedence value, a public key,
+   algorithm type, and an optional gateway address.
+
+</p></font><pre>
+    0                   1                   2                   3  
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |  precedence   | gateway type  |  algorithm  |     gateway     |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-------------+                 +
+   ~                            gateway                            ~
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               /
+   /                          public key                           /
+   /                                                               /
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|
+</pre><font face="verdana, helvetica, arial, sans-serif" size="2">
+
+<a name="rfc.section.2.2"></a><h4><a name="anchor6">2.2</a>&nbsp;RDATA format - precedence</h4>
+
+<p>
+This is an 8-bit precedence for this record. This is interpreted in
+the same way as the PREFERENCE field described in section
+3.3.9 of RFC1035 <a href="#RFC1035">[2]</a>. 
+
+</p>
+<p>
+Gateways listed in IPSECKEY records with  lower precedence are
+to be attempted first. Where there is a tie in precedence, the order
+should be non-deterministic.
+
+</p>
+<a name="rfc.section.2.3"></a><h4><a name="algotype">2.3</a>&nbsp;RDATA format - algorithm type</h4>
+
+<p>
+The algorithm type field identifies the public key's cryptographic
+algorithm and determines the format of the public key field.  
+
+</p>
+<p>
+A value of 0 indicates that no key is present.
+
+</p>
+<p>
+The following values are defined:
+  
+<blockquote class="text"><dl>
+<dt>1</dt>
+<dd>A DSA key is present, in the format defined in RFC2536 <a href="#RFC2536">[11]</a>
+</dd>
+<dt>2</dt>
+<dd>A RSA key is present, in the format defined in RFC3110 <a href="#RFC3110">[12]</a>
+</dd>
+</dl></blockquote><p>
+</p>
+<a name="rfc.section.2.4"></a><h4><a name="gatewaytype">2.4</a>&nbsp;RDATA format - gateway type</h4>
+
+<p>
+The gateway type field indicates the format of the information that
+is stored in the gateway field.
+
+</p>
+<p>
+The following values are defined:
+  
+<blockquote class="text"><dl>
+<dt>0</dt>
+<dd>No gateway is present
+</dd>
+<dt>1</dt>
+<dd>A 4-byte IPv4 address is present
+</dd>
+<dt>2</dt>
+<dd>A 16-byte IPv6 address is present
+</dd>
+<dt>3</dt>
+<dd>A wire-encoded domain name is present. The wire-encoded
+format is self-describing, so the length is implicit. The domain name
+MUST NOT be compressed.
+</dd>
+</dl></blockquote><p>
+</p>
+<a name="rfc.section.2.5"></a><h4><a name="anchor7">2.5</a>&nbsp;RDATA format - gateway</h4>
+
+<p>
+The gateway field indicates a gateway to which an IPsec tunnel may be
+created in order to reach the entity named by this resource record.
+
+</p>
+<p>
+There are three formats:
+
+</p>
+<p>
+A 32-bit IPv4 address is present in the gateway field. The data
+portion is an IPv4 address as described in section 3.4.1 of
+<a href="#RFC1035">RFC1035</a>[2].  This is a 32-bit number in network byte order.
+
+</p>
+<p>A 128-bit IPv6 address is present in the gateway field.
+The data portion is an IPv6 address as described in section 2.2 of
+<a href="#RFC1886">RFC1886</a>[7]. This is a 128-bit number in network byte order.
+
+</p>
+<p>
+The gateway field is a normal wire-encoded domain name, as described
+in section 3.3 of RFC1035 <a href="#RFC1035">[2]</a>. Compression MUST NOT be used. 
+
+</p>
+<a name="rfc.section.2.6"></a><h4><a name="anchor8">2.6</a>&nbsp;RDATA format - public keys</h4>
+
+<p>
+Both of the public key types defined in this document (RSA and DSA)
+inherit their public key formats from the corresponding KEY RR formats. 
+Specifically, the public key field contains the algorithm-specific
+portion of the KEY RR RDATA, which is all of the KEY RR DATA after the
+first four octets.  This is the same portion of the KEY RR that must be
+specified by documents that define a DNSSEC algorithm.  
+Those documents also specify a message digest to be used for generation
+of SIG RRs; that specification is not relevant for IPSECKEY RR.
+
+</p>
+<p>
+Future algorithms, if they are to be used by both DNSSEC (in the KEY
+RR) and IPSECKEY, are likely to use the same public key encodings in
+both records.  Unless otherwise specified, the IPSECKEY public key
+field will contain the algorithm-specific portion of the KEY RR RDATA
+for the corresponding algorithm.  The algorithm must still be
+designated for use by IPSECKEY, and an IPSECKEY algorithm type number
+(which might be different than the DNSSEC algorithm number) must be
+assigned to it.
+
+</p>
+<p>The DSA key format is defined in RFC2536 <a href="#RFC2536">[11]</a>
+</p>
+<p>The RSA key format is defined in RFC3110 <a href="#RFC3110">[12]</a>,
+with the following changes:
+</p>
+<p>
+The earlier definition of RSA/MD5 in RFC2065 limited the exponent and
+modulus to 2552 bits in length.  RFC3110 extended that limit to 4096
+bits for RSA/SHA1 keys.  The IPSECKEY RR imposes no length limit on
+RSA public keys, other than the 65535 octet limit imposed by the
+two-octet length encoding.  This length extension is applicable only
+to IPSECKEY and not to KEY RRs. 
+
+</p>
+<a name="anchor9"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<a name="rfc.section.3"></a><h3>3.&nbsp;Presentation formats</h3>
+
+<a name="rfc.section.3.1"></a><h4><a name="anchor10">3.1</a>&nbsp;Representation of IPSECKEY RRs</h4>
+
+<p>
+   IPSECKEY RRs may appear in a zone data master file.
+   The precedence, gateway type and algorithm and gateway fields are REQUIRED.
+   The base64 encoded public key block is OPTIONAL; if not present,
+   then the public key field of the resource record MUST be construed
+   as being zero octets in length.
+
+</p>
+<p>
+   The algorithm field is an unsigned integer. No mnemonics are defined.
+
+</p>
+<p>
+   If no gateway is to be indicated, then the gateway type field MUST
+   be zero, and the gateway field MUST be "."
+
+</p>
+<p>
+   The Public Key field is represented as a Base64 encoding of the
+   Public Key.  Whitespace is allowed within the Base64 text.  For a
+   definition of Base64 encoding, see
+<a href="#RFC1521">RFC1521</a>[3] Section 5.2.
+
+</p>
+<p>
+   The general presentation for the record as as follows:
+</p>
+</font><pre>
+IN     IPSECKEY ( precedence gateway-type algorithm
+                  gateway base64-encoded-public-key )
+</pre><font face="verdana, helvetica, arial, sans-serif" size="2">
+<p>
+
+</p>
+<a name="rfc.section.3.2"></a><h4><a name="anchor11">3.2</a>&nbsp;Examples</h4>
+
+<p> 
+An example of a node 192.0.2.38 that will accept IPsec tunnels on its
+own behalf.
+</p>
+</font><pre>
+38.2.0.192.in-addr.arpa. 7200 IN     IPSECKEY ( 10 1 2 
+                 192.0.2.38
+                 AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )
+</pre><font face="verdana, helvetica, arial, sans-serif" size="2">
+<p>
+
+</p>
+<p> 
+An example of a node, 192.0.2.38 that has published its key only.
+</p>
+</font><pre>
+38.2.0.192.in-addr.arpa. 7200 IN     IPSECKEY ( 10 0 2
+                 .
+                 AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )
+</pre><font face="verdana, helvetica, arial, sans-serif" size="2">
+<p>
+
+</p>
+<p> 
+An example of a node, 192.0.2.38 that has delegated authority to the node
+192.0.2.3.
+</p>
+</font><pre>
+38.2.0.192.in-addr.arpa. 7200 IN     IPSECKEY ( 10 1 2
+                 192.0.2.3
+                 AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )
+</pre><font face="verdana, helvetica, arial, sans-serif" size="2">
+<p>
+
+</p>
+<p> 
+An example of a node, 192.0.1.38 that has delegated authority to the node
+with the identity "mygateway.example.com".
+</p>
+</font><pre>
+38.1.0.192.in-addr.arpa. 7200 IN     IPSECKEY ( 10 3 2
+                 mygateway.example.com.
+                 AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )
+</pre><font face="verdana, helvetica, arial, sans-serif" size="2">
+<p>
+
+</p>
+<p> 
+An example of a node, 2001:0DB8:0200:1:210:f3ff:fe03:4d0 that has
+delegated authority to the node 2001:0DB8:c000:0200:2::1
+</p>
+</font><pre>
+$ORIGIN 1.0.0.0.0.0.2.8.B.D.0.1.0.0.2.ip6.int.
+0.d.4.0.3.0.e.f.f.f.3.f.0.1.2.0 7200 IN     IPSECKEY ( 10 2 2
+                 2001:0DB8:0:8002::2000:1
+                 AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )
+</pre><font face="verdana, helvetica, arial, sans-serif" size="2">
+<p>
+
+</p>
+<a name="anchor12"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<a name="rfc.section.4"></a><h3>4.&nbsp;Security Considerations</h3>
+
+<p>
+   This entire memo pertains to the provision of public keying material
+   for use by key management protocols such as ISAKMP/IKE (RFC2407)
+   <a href="#RFC2407">[9]</a>.
+
+</p>
+<p>
+The IPSECKEY resource record contains information that SHOULD be
+communicated to the end client in an integral fashion - i.e. free from
+modification. The form of this channel is up to the consumer of the
+data - there must be a trust relationship between the end consumer of this
+resource record and the server. This relationship may be end-to-end
+DNSSEC validation, a TSIG or SIG(0) channel to another secure source,
+a secure local channel on the host, or some combination of the above.
+
+</p>
+<p>
+The keying material provided by the IPSECKEY resource record is not
+sensitive to passive attacks. The keying material may be freely
+disclosed to any party without any impact on the security properties
+of the resulting IPsec session: IPsec and IKE provide for defense
+against both active and passive attacks.
+
+</p>
+<p>
+   Any user of this resource record MUST carefully document their trust
+   model, and why the trust model of DNSSEC is appropriate, if that is
+   the secure channel used.
+
+</p>
+<a name="rfc.section.4.1"></a><h4><a name="anchor13">4.1</a>&nbsp;Active attacks against unsecured IPSECKEY resource records</h4>
+
+<p>
+This section deals with active attacks against the DNS. These attacks
+require that DNS requests and responses be intercepted and changed.
+DNSSEC is designed to defend against attacks of this kind.
+
+</p>
+<p>
+The first kind of active attack is when the attacker replaces the
+keying material with either a key under its control or with garbage.
+
+</p>
+<p>
+If the attacker is not able to mount a subsequent 
+man-in-the-middle attack on the IKE negotiation after replacing the
+public key, then this will result in a denial of service, as the
+authenticator used by IKE would fail.  
+
+</p>
+<p>
+If the attacker is able to both to mount active attacks against DNS
+and is also in a position to perform a man-in-the-middle attack on IKE and
+IPsec negotiations, then the attacker will be in a position to compromise
+the resulting IPsec channel. Note that an attacker must be able to
+perform active DNS attacks on both sides of the IKE negotiation in
+order for this to succeed. 
+
+</p>
+<p>
+The second kind of active attack is one in which the attacker replaces
+the the gateway address to point to a node under the attacker's
+control. The attacker can then either replace the public key or remove
+it, thus providing an IPSECKEY record of its own to match the
+gateway address. 
+
+</p>
+<p>
+This later form creates a simple man-in-the-middle since the attacker
+can then create a second tunnel to the real destination. Note that, as before,
+this requires that the attacker also mount an active attack against
+the responder. 
+
+</p>
+<p>
+Note that the man-in-the-middle can not just forward cleartext
+packets to the original destination. While the destination may be
+willing to speak in the clear, replying to the original sender,
+the sender will have already created a policy expecting ciphertext.
+Thus, the attacker will need to intercept traffic from both sides. In some
+cases, the attacker may be able to accomplish the full intercept by use
+of Network Addresss/Port Translation (NAT/NAPT) technology.
+
+</p>
+<p>
+Note that the danger here only applies to cases where the gateway
+field of the IPSECKEY RR indicates a different entity than the owner
+name of the IPSECKEY RR.  In cases where the end-to-end integrity of
+the IPSECKEY RR is suspect, the end client MUST restrict its use
+of the IPSECKEY RR to cases where the RR owner name matches the
+content of the gateway field.
+
+</p>
+<a name="anchor14"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<a name="rfc.section.5"></a><h3>5.&nbsp;IANA Considerations</h3>
+
+<p>
+This document updates the IANA Registry for DNS Resource Record Types
+by assigning type X to the IPSECKEY record.  
+
+</p>
+<p>
+This document creates an IANA registry for the algorithm type field.
+
+</p>
+<p>
+Values 0, 1 and 2 are defined in <a href="#algotype">RDATA format - algorithm type</a>. Algorithm numbers
+3 through 255 can be assigned by IETF Consensus (<a href="#RFC2434">see RFC2434</a>[6]).
+
+</p>
+<p>
+This document creates an IANA registry for the gateway type field.
+
+</p>
+<p>
+Values 0, 1, 2 and 3 are defined in <a href="#gatewaytype">RDATA format - gateway type</a>.
+Algorithm numbers 4 through 255 can be assigned by
+Standards Action (<a href="#RFC2434">see RFC2434</a>[6]).
+
+</p>
+<a name="anchor15"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<a name="rfc.section.6"></a><h3>6.&nbsp;Acknowledgments</h3>
+
+<p>
+My thanks to Paul Hoffman, Sam Weiler, Jean-Jacques Puig, Rob Austein,
+and Olafur Gurmundsson who reviewed this document carefully.
+Additional thanks to Olafur Gurmundsson for a reference implementation.
+
+</p>
+<a name="rfc.references1"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<h3>Normative references</h3>
+<table width="99%" border="0">
+<tr><td class="author-text" valign="top"><b><a name="RFC1034">[1]</a></b></td>
+<td class="author-text">Mockapetris, P., "<a href="ftp://ftp.isi.edu/in-notes/rfc1034.txt">Domain names - concepts and facilities</a>", STD 13, RFC 1034, November 1987.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC1035">[2]</a></b></td>
+<td class="author-text"><a href="mailto:">Mockapetris, P.</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc1035.txt">Domain names - implementation and specification</a>", STD 13, RFC 1035, November 1987.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC1521">[3]</a></b></td>
+<td class="author-text"><a href="mailto:nsb@bellcore.com">Borenstein, N.</a> and <a href="mailto:">N. Freed</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc1521.txt">MIME (Multipurpose Internet Mail Extensions) Part One: Mechanisms for Specifying and Describing the Format of Internet Message Bodies</a>", RFC 1521, September 1993.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC2026">[4]</a></b></td>
+<td class="author-text"><a href="mailto:sob@harvard.edu">Bradner, S.</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2026.txt">The Internet Standards Process -- Revision 3</a>", BCP 9, RFC 2026, October 1996.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC2065">[5]</a></b></td>
+<td class="author-text"><a href="mailto:dee@cybercash.com">Eastlake, D.</a> and <a href="mailto:charlie_kaufman@iris.com">C. Kaufman</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2065.txt">Domain Name System Security Extensions</a>", RFC 2065, January 1997.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC2434">[6]</a></b></td>
+<td class="author-text"><a href="mailto:narten@raleigh.ibm.com">Narten, T.</a> and <a href="mailto:Harald@Alvestrand.no">H. Alvestrand</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2434.txt">Guidelines for Writing an IANA Considerations Section in RFCs</a>", BCP 26, RFC 2434, October 1998.</td></tr>
+</table>
+
+<a name="rfc.references2"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<h3>Non-normative references</h3>
+<table width="99%" border="0">
+<tr><td class="author-text" valign="top"><b><a name="RFC1886">[7]</a></b></td>
+<td class="author-text"><a href="mailto:set@thumper.bellcore.com">Thomson, S.</a> and <a href="mailto:Christian.Huitema@MIRSA.INRIA.FR">C. Huitema</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc1886.txt">DNS Extensions to support IP version 6</a>", RFC 1886, December 1995.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC2119">[8]</a></b></td>
+<td class="author-text"><a href="mailto:-">Bradner, S.</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2119.txt">Key words for use in RFCs to Indicate Requirement Levels</a>", BCP 14, RFC 2119, March 1997.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC2407">[9]</a></b></td>
+<td class="author-text"><a href="mailto:ddp@network-alchemy.com">Piper, D.</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2407.txt">The Internet IP Security Domain of Interpretation for ISAKMP</a>", RFC 2407, November 1998.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC2535">[10]</a></b></td>
+<td class="author-text"><a href="mailto:dee3@us.ibm.com">Eastlake, D.</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2535.txt">Domain Name System Security Extensions</a>", RFC 2535, March 1999.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC2536">[11]</a></b></td>
+<td class="author-text"><a href="mailto:dee3@us.ibm.com">Eastlake, D.</a>, "<a href="ftp://ftp.isi.edu/in-notes/rfc2536.txt">DSA KEYs and SIGs in the Domain Name System (DNS)</a>", RFC 2536, March 1999.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC3110">[12]</a></b></td>
+<td class="author-text">Eastlake, D., "<a href="ftp://ftp.isi.edu/in-notes/rfc3110.txt">RSA/SHA-1 SIGs and RSA KEYs in the Domain Name System (DNS)</a>", RFC 3110, May 2001.</td></tr>
+<tr><td class="author-text" valign="top"><b><a name="RFC3445">[13]</a></b></td>
+<td class="author-text">Massey, D. and S. Rose, "<a href="ftp://ftp.isi.edu/in-notes/rfc3445.txt">Limiting the Scope of the KEY Resource Record (RR)</a>", RFC 3445, December 2002.</td></tr>
+</table>
+
+<a name="rfc.authors"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<h3>Author's Address</h3>
+<table width="99%" border="0" cellpadding="0" cellspacing="0">
+<tr><td class="author-text">&nbsp;</td>
+<td class="author-text">Michael C. Richardson</td></tr>
+<tr><td class="author-text">&nbsp;</td>
+<td class="author-text">Sandelman Software Works</td></tr>
+<tr><td class="author-text">&nbsp;</td>
+<td class="author-text">470 Dawson Avenue</td></tr>
+<tr><td class="author-text">&nbsp;</td>
+<td class="author-text">Ottawa, ON  K1Z 5V7</td></tr>
+<tr><td class="author-text">&nbsp;</td>
+<td class="author-text">CA</td></tr>
+<tr><td class="author" align="right">EMail:&nbsp;</td>
+<td class="author-text"><a href="mailto:mcr@sandelman.ottawa.on.ca">mcr@sandelman.ottawa.on.ca</a></td></tr>
+<tr><td class="author" align="right">URI:&nbsp;</td>
+<td class="author-text"><a href="http://www.sandelman.ottawa.on.ca/">http://www.sandelman.ottawa.on.ca/</a></td></tr>
+</table>
+<a name="rfc.copyright"><br><hr size="1" shade="0"></a>
+<table border="0" cellpadding="0" cellspacing="2" width="30" height="15" align="right"><tr><td bgcolor="#990000" align="center" width="30" height="15"><a href="#toc" CLASS="link2"><font face="monaco, MS Sans Serif" color="#ffffff" size="1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
+<h3>Full Copyright Statement</h3>
+<p class='copyright'>
+Copyright (C) The Internet Society (2003). All Rights Reserved.</p>
+<p class='copyright'>
+This document and translations of it may be copied and furnished to
+others, and derivative works that comment on or otherwise explain it
+or assist in its implementation may be prepared, copied, published and
+distributed, in whole or in part, without restriction of any kind,
+provided that the above copyright notice and this paragraph are
+included on all such copies and derivative works. However, this
+document itself may not be modified in any way, such as by removing
+the copyright notice or references to the Internet Society or other
+Internet organizations, except as needed for the purpose of
+developing Internet standards in which case the procedures for
+copyrights defined in the Internet Standards process must be
+followed, or as required to translate it into languages other than
+English.</p>
+<p class='copyright'>
+The limited permissions granted above are perpetual and will not be
+revoked by the Internet Society or its successors or assigns.</p>
+<p class='copyright'>
+This document and the information contained herein is provided on an
+&quot;AS IS&quot; basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
+TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
+BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
+HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
+MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.</p>
+<h3>Acknowledgement</h3>
+<p class='copyright'>
+Funding for the RFC Editor function is currently provided by the
+Internet Society.</p>
+</font></body></html>
diff --git a/doc/src/draft-richardson-ipsec-rr.xml b/doc/src/draft-richardson-ipsec-rr.xml
new file mode 100644
index 000000000..e51b32615
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+++ b/doc/src/draft-richardson-ipsec-rr.xml
@@ -0,0 +1,560 @@
+<?xml version="1.0"?>
+<!DOCTYPE rfc SYSTEM "rfc2629.dtd">
+<?rfc toc="yes"?>
+
+<rfc ipr="full2026" docName="draft-ietf-ipseckey-rr-07.txt">
+
+<front>
+  <area>Security</area>
+  <workgroup>IPSECKEY WG</workgroup>
+  <title abbrev="ipsecrr">
+     A method for storing IPsec keying material in DNS.
+  </title>
+
+  <author initials="M." surname="Richardson" fullname="Michael C. Richardson">
+    <organization abbrev="SSW">Sandelman Software Works</organization>
+    <address>
+      <postal>   
+        <street>470 Dawson Avenue</street>
+        <city>Ottawa</city>
+        <region>ON</region>
+        <code>K1Z 5V7</code>
+        <country>CA</country>
+      </postal>
+      <email>mcr@sandelman.ottawa.on.ca</email>
+      <uri>http://www.sandelman.ottawa.on.ca/</uri>
+    </address>
+  </author>
+
+  <date month="September" year="2003" />
+
+<abstract>
+  <t>
+This document describes a new resource record for DNS. This record may be
+used to store public keys for use in IPsec systems. 
+</t>
+
+<t>
+This record replaces the functionality of the sub-type #1 of the KEY Resource
+Record, which has been obsoleted by RFC3445.
+</t>
+</abstract>
+
+</front>
+
+<middle>
+
+<section title="Introduction">
+<t>
+   The type number for the IPSECKEY RR is TBD.
+</t>
+
+<section title="Overview">
+<t>
+   The IPSECKEY resource record (RR) is used to publish a public key that is
+   to be associated with a Domain Name System (DNS) name for use with the
+   IPsec protocol suite.  This can be the  public key of a host,
+   network, or application (in the case of per-port keying).
+</t>
+
+<t>
+      The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
+      NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and
+      "OPTIONAL" in this document are to be interpreted as described in
+      RFC2119 <xref target="RFC2119" />.
+</t>
+</section>
+
+<section title="Usage Criteria">
+<t>
+   An IPSECKEY resource record SHOULD be used in combination with DNSSEC
+unless some other means of authenticating the IPSECKEY resource record
+is available.
+</t>
+
+<t>  
+   It is expected that there will often be multiple IPSECKEY resource
+   records at the same name. This will be due to the presence
+   of multiple gateways and the need to rollover keys.
+
+</t>
+
+<t>
+   This resource record is class independent.
+</t>
+</section>
+</section>
+
+<section title="Storage formats">
+
+<section title="IPSECKEY RDATA format">
+
+<t>
+   The RDATA for an IPSECKEY RR consists of a precedence value, a public key,
+   algorithm type, and an optional gateway address.
+</t>
+
+<artwork><![CDATA[
+    0                   1                   2                   3  
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |  precedence   | gateway type  |  algorithm  |     gateway     |
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-------------+                 +
+   ~                            gateway                            ~
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+   |                                                               /
+   /                          public key                           /
+   /                                                               /
+   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|
+]]></artwork>
+</section>
+
+<section title="RDATA format - precedence">
+<t>
+This is an 8-bit precedence for this record. This is interpreted in
+the same way as the PREFERENCE field described in section
+3.3.9 of RFC1035 <xref target="RFC1035" />. 
+</t>
+<t>
+Gateways listed in IPSECKEY records with  lower precedence are
+to be attempted first. Where there is a tie in precedence, the order
+should be non-deterministic.
+</t>
+</section>
+
+<section anchor="algotype" title="RDATA format - algorithm type">
+<t>
+The algorithm type field identifies the public key's cryptographic
+algorithm and determines the format of the public key field.  
+</t>
+
+<t>
+A value of 0 indicates that no key is present.
+</t>
+
+<t>
+The following values are defined:
+  <list style="hanging">
+  <t hangText="1">A DSA key is present, in the format defined in RFC2536 <xref target="RFC2536" /></t>
+  <t hangText="2">A RSA key is present, in the format defined in RFC3110 <xref target="RFC3110" /></t>
+  </list>
+</t>
+
+</section>
+
+<section anchor="gatewaytype" title="RDATA format - gateway type">
+<t>
+The gateway type field indicates the format of the information that
+is stored in the gateway field.
+</t>
+
+<t>
+The following values are defined:
+  <list style="hanging">
+  <t hangText="0">No gateway is present</t>
+  <t hangText="1">A 4-byte IPv4 address is present</t>
+  <t hangText="2">A 16-byte IPv6 address is present</t>
+  <t hangText="3">A wire-encoded domain name is present. The wire-encoded
+format is self-describing, so the length is implicit. The domain name
+MUST NOT be compressed.</t>
+  </list>
+</t>
+
+</section>
+
+<section title="RDATA format - gateway">
+<t>
+The gateway field indicates a gateway to which an IPsec tunnel may be
+created in order to reach the entity named by this resource record.
+</t>
+<t>
+There are three formats:
+</t>
+
+<t>
+A 32-bit IPv4 address is present in the gateway field. The data
+portion is an IPv4 address as described in section 3.4.1 of
+<xref target="RFC1035">RFC1035</xref>.  This is a 32-bit number in network byte order.
+</t>
+
+<t>A 128-bit IPv6 address is present in the gateway field.
+The data portion is an IPv6 address as described in section 2.2 of
+<xref target="RFC1886">RFC1886</xref>. This is a 128-bit number in network byte order.
+</t>
+
+<t>
+The gateway field is a normal wire-encoded domain name, as described
+in section 3.3 of RFC1035 <xref target="RFC1035" />. Compression MUST NOT be used. 
+</t>
+
+</section>
+
+<section title="RDATA format - public keys">
+<t>
+Both of the public key types defined in this document (RSA and DSA)
+inherit their public key formats from the corresponding KEY RR formats. 
+Specifically, the public key field contains the algorithm-specific
+portion of the KEY RR RDATA, which is all of the KEY RR DATA after the
+first four octets.  This is the same portion of the KEY RR that must be
+specified by documents that define a DNSSEC algorithm.  
+Those documents also specify a message digest to be used for generation
+of SIG RRs; that specification is not relevant for IPSECKEY RR.
+</t>
+
+<t>
+Future algorithms, if they are to be used by both DNSSEC (in the KEY
+RR) and IPSECKEY, are likely to use the same public key encodings in
+both records.  Unless otherwise specified, the IPSECKEY public key
+field will contain the algorithm-specific portion of the KEY RR RDATA
+for the corresponding algorithm.  The algorithm must still be
+designated for use by IPSECKEY, and an IPSECKEY algorithm type number
+(which might be different than the DNSSEC algorithm number) must be
+assigned to it.
+</t>
+
+<t>The DSA key format is defined in RFC2536 <xref target="RFC2536" /></t>.
+
+<t>The RSA key format is defined in RFC3110 <xref target="RFC3110" />,
+with the following changes:</t>
+
+<t>
+The earlier definition of RSA/MD5 in RFC2065 limited the exponent and
+modulus to 2552 bits in length.  RFC3110 extended that limit to 4096
+bits for RSA/SHA1 keys.  The IPSECKEY RR imposes no length limit on
+RSA public keys, other than the 65535 octet limit imposed by the
+two-octet length encoding.  This length extension is applicable only
+to IPSECKEY and not to KEY RRs. 
+</t>
+
+</section>
+
+</section>
+
+
+
+<section title="Presentation formats">
+
+<section title="Representation of IPSECKEY RRs">
+<t>
+   IPSECKEY RRs may appear in a zone data master file.
+   The precedence, gateway type and algorithm and gateway fields are REQUIRED.
+   The base64 encoded public key block is OPTIONAL; if not present,
+   then the public key field of the resource record MUST be construed
+   as being zero octets in length.
+</t>
+<t>
+   The algorithm field is an unsigned integer. No mnemonics are defined.
+</t>
+<t>
+   If no gateway is to be indicated, then the gateway type field MUST
+   be zero, and the gateway field MUST be "."
+</t>
+
+<t>
+   The Public Key field is represented as a Base64 encoding of the
+   Public Key.  Whitespace is allowed within the Base64 text.  For a
+   definition of Base64 encoding, see
+<xref target="RFC1521">RFC1521</xref> Section 5.2.
+</t>
+
+   
+<t>
+   The general presentation for the record as as follows:
+<artwork><![CDATA[
+IN     IPSECKEY ( precedence gateway-type algorithm
+                  gateway base64-encoded-public-key )
+]]></artwork>
+</t>
+</section>
+
+
+<section title="Examples">
+<t> 
+An example of a node 192.0.2.38 that will accept IPsec tunnels on its
+own behalf.
+<artwork><![CDATA[
+38.2.0.192.in-addr.arpa. 7200 IN     IPSECKEY ( 10 1 2 
+                 192.0.2.38
+                 AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )
+]]></artwork>
+</t>
+
+<t> 
+An example of a node, 192.0.2.38 that has published its key only.
+<artwork><![CDATA[
+38.2.0.192.in-addr.arpa. 7200 IN     IPSECKEY ( 10 0 2
+                 .
+                 AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )
+]]></artwork>
+</t>
+
+<t> 
+An example of a node, 192.0.2.38 that has delegated authority to the node
+192.0.2.3.
+<artwork><![CDATA[
+38.2.0.192.in-addr.arpa. 7200 IN     IPSECKEY ( 10 1 2
+                 192.0.2.3
+                 AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )
+]]></artwork>
+</t>
+
+<t> 
+An example of a node, 192.0.1.38 that has delegated authority to the node
+with the identity "mygateway.example.com".
+<artwork><![CDATA[
+38.1.0.192.in-addr.arpa. 7200 IN     IPSECKEY ( 10 3 2
+                 mygateway.example.com.
+                 AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )
+]]></artwork>
+</t>
+
+<t> 
+An example of a node, 2001:0DB8:0200:1:210:f3ff:fe03:4d0 that has
+delegated authority to the node 2001:0DB8:c000:0200:2::1
+<artwork><![CDATA[
+$ORIGIN 1.0.0.0.0.0.2.8.B.D.0.1.0.0.2.ip6.int.
+0.d.4.0.3.0.e.f.f.f.3.f.0.1.2.0 7200 IN     IPSECKEY ( 10 2 2
+                 2001:0DB8:0:8002::2000:1
+                 AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )
+]]></artwork>
+</t>
+
+</section>
+</section>
+
+<section title="Security Considerations">
+<t>
+   This entire memo pertains to the provision of public keying material
+   for use by key management protocols such as ISAKMP/IKE (RFC2407)
+   <xref target="RFC2407" />.
+</t>
+
+<t>
+The IPSECKEY resource record contains information that SHOULD be
+communicated to the end client in an integral fashion - i.e. free from
+modification. The form of this channel is up to the consumer of the
+data - there must be a trust relationship between the end consumer of this
+resource record and the server. This relationship may be end-to-end
+DNSSEC validation, a TSIG or SIG(0) channel to another secure source,
+a secure local channel on the host, or some combination of the above.
+</t>
+
+<t>
+The keying material provided by the IPSECKEY resource record is not
+sensitive to passive attacks. The keying material may be freely
+disclosed to any party without any impact on the security properties
+of the resulting IPsec session: IPsec and IKE provide for defense
+against both active and passive attacks.
+</t>
+
+<t>
+   Any user of this resource record MUST carefully document their trust
+   model, and why the trust model of DNSSEC is appropriate, if that is
+   the secure channel used.
+</t>
+
+<section title="Active attacks against unsecured IPSECKEY resource records">
+<t>
+This section deals with active attacks against the DNS. These attacks
+require that DNS requests and responses be intercepted and changed.
+DNSSEC is designed to defend against attacks of this kind.
+</t>
+
+<t>
+The first kind of active attack is when the attacker replaces the
+keying material with either a key under its control or with garbage.
+</t>
+
+<t>
+If the attacker is not able to mount a subsequent 
+man-in-the-middle attack on the IKE negotiation after replacing the
+public key, then this will result in a denial of service, as the
+authenticator used by IKE would fail.  
+</t>
+
+<t>
+If the attacker is able to both to mount active attacks against DNS
+and is also in a position to perform a man-in-the-middle attack on IKE and
+IPsec negotiations, then the attacker will be in a position to compromise
+the resulting IPsec channel. Note that an attacker must be able to
+perform active DNS attacks on both sides of the IKE negotiation in
+order for this to succeed. 
+</t>
+
+<t>
+The second kind of active attack is one in which the attacker replaces
+the the gateway address to point to a node under the attacker's
+control. The attacker can then either replace the public key or remove
+it, thus providing an IPSECKEY record of its own to match the
+gateway address. 
+</t>
+
+<t>
+This later form creates a simple man-in-the-middle since the attacker
+can then create a second tunnel to the real destination. Note that, as before,
+this requires that the attacker also mount an active attack against
+the responder. 
+</t>
+
+<t>
+Note that the man-in-the-middle can not just forward cleartext
+packets to the original destination. While the destination may be
+willing to speak in the clear, replying to the original sender,
+the sender will have already created a policy expecting ciphertext.
+Thus, the attacker will need to intercept traffic from both sides. In some
+cases, the attacker may be able to accomplish the full intercept by use
+of Network Addresss/Port Translation (NAT/NAPT) technology.
+</t>
+
+<t>
+Note that the danger here only applies to cases where the gateway
+field of the IPSECKEY RR indicates a different entity than the owner
+name of the IPSECKEY RR.  In cases where the end-to-end integrity of
+the IPSECKEY RR is suspect, the end client MUST restrict its use
+of the IPSECKEY RR to cases where the RR owner name matches the
+content of the gateway field.
+</t>
+</section>
+
+</section>
+
+<section title="IANA Considerations">
+<t>
+This document updates the IANA Registry for DNS Resource Record Types
+by assigning type X to the IPSECKEY record.  
+</t>
+
+<t>
+This document creates an IANA registry for the algorithm type field.
+</t>
+<t>
+Values 0, 1 and 2 are defined in <xref target="algotype" />. Algorithm numbers
+3 through 255 can be assigned by IETF Consensus (<xref target="RFC2434">see RFC2434</xref>).
+</t>
+
+<t>
+This document creates an IANA registry for the gateway type field.
+</t>
+<t>
+Values 0, 1, 2 and 3 are defined in <xref target="gatewaytype" />.
+Algorithm numbers 4 through 255 can be assigned by
+Standards Action (<xref target="RFC2434">see RFC2434</xref>).
+</t>
+
+
+
+</section>
+
+<section title="Acknowledgments">
+<t>
+My thanks to Paul Hoffman, Sam Weiler, Jean-Jacques Puig, Rob Austein,
+and Olafur Gurmundsson who reviewed this document carefully.
+Additional thanks to Olafur Gurmundsson for a reference implementation.
+</t>
+</section>
+
+</middle>
+
+<back>
+<references title="Normative references">
+<!-- DNSSEC -->
+<?rfc include="reference.RFC.1034" ?>
+<?rfc include="reference.RFC.1035" ?>
+<?rfc include="reference.RFC.1521" ?>
+<?rfc include="reference.RFC.2026" ?>
+<?rfc include="reference.RFC.2065" ?>
+<?rfc include="reference.RFC.2434" ?>
+</references>
+
+<references title="Non-normative references">
+<?rfc include="reference.RFC.1886" ?>
+<?rfc include="reference.RFC.2119" ?>
+<?rfc include="reference.RFC.2407" ?>
+<?rfc include="reference.RFC.2535" ?>
+<?rfc include="reference.RFC.2536" ?>
+<?rfc include="reference.RFC.3110" ?>
+<?rfc include="reference.RFC.3445" ?>
+</references>
+</back>
+</rfc>
+<!--
+  $Id: draft-richardson-ipsec-rr.xml,v 1.1 2004/03/15 20:35:24 as Exp $
+
+  $Log: draft-richardson-ipsec-rr.xml,v $
+  Revision 1.1  2004/03/15 20:35:24  as
+  added files from freeswan-2.04-x509-1.5.3
+
+  Revision 1.23  2003/09/04 23:26:09  mcr
+  	more nits.
+
+  Revision 1.22  2003/08/16 15:55:35  mcr
+  	fixed version to -06.
+
+  Revision 1.21  2003/08/16 15:52:32  mcr
+  	Sam's comments on IANA considerations.
+
+  Revision 1.20  2003/07/27 22:57:54  mcr
+  	updated document with new text about a seperate registry
+  	for the algorithm type.
+
+  Revision 1.19  2003/06/30 01:51:50  mcr
+  	minor typo fixes.
+
+  Revision 1.18  2003/06/16 17:45:00  mcr
+  	adjusted date on rev-04.
+
+  Revision 1.17  2003/06/16 17:41:30  mcr
+  	revision -04
+
+  Revision 1.16  2003/06/16 17:39:20  mcr
+  	adjusted typos, and adjusted IANA considerations.
+
+  Revision 1.15  2003/05/26 19:31:23  mcr
+  	updates to drafts - IPSEC RR - SC versions, and RFC3526
+  	reference in OE draft.
+
+  Revision 1.14  2003/05/23 13:57:40  mcr
+  	updated draft ##.
+
+  Revision 1.13  2003/05/23 13:54:45  mcr
+  	updated month on draft.
+
+  Revision 1.12  2003/05/21 15:42:49  mcr
+  	new SC section with comments from Rob Austein.
+
+  Revision 1.11  2003/05/20 20:52:22  mcr
+  	new security considerations section.
+
+  Revision 1.10  2003/05/20 19:07:47  mcr
+  	rewrote Security Considerations.
+
+  Revision 1.9  2003/05/20 18:17:09  mcr
+  	nits from Rob Austein.
+
+  Revision 1.8  2003/04/29 00:44:59  mcr
+  	updates according to WG consensus: restored three-way
+  	gateway field type.
+
+  Revision 1.7  2003/03/30 17:00:29  mcr
+  	updates according to community feedback.
+
+  Revision 1.6  2003/03/19 02:20:24  mcr
+  	updated draft based upon comments from working group
+
+  Revision 1.5  2003/02/23 22:39:22  mcr
+  	updates to IPSECKEY draft.
+
+  Revision 1.4  2003/02/21 04:39:04  mcr
+  	updated drafts, and added crosscompile.html
+
+  Revision 1.3  2003/01/17 16:26:34  mcr
+  	updated IPSEC KEY draft with restrictions.
+
+  Revision 1.2  2002/08/26 18:20:54  mcr
+  	updated documents
+
+  Revision 1.1  2002/08/10 20:05:33  mcr
+  	document proposing IPSECKEY Resource Record
+
+
+!>
diff --git a/doc/src/faq.html b/doc/src/faq.html
new file mode 100644
index 000000000..f62fc1c88
--- /dev/null
+++ b/doc/src/faq.html
@@ -0,0 +1,2770 @@
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>FreeS/WAN FAQ</title>
+  <meta name="keywords" content="Linux, IPsec, VPN, security, FreeSWAN, FAQ">
+  <!--
+
+  Written by Sandy Harris for the Linux FreeS/WAN project
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: faq.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+
+<body>
+<h1>FreeS/WAN FAQ</h1>
+
+<p>This is a collection of questions and answers, mostly taken from the
+FreeS/WAN <a href="mail.html">mailing list</a>. See the project <a
+href="http://www.freeswan.org/">web site</a> for more information. All the
+FreeS/WAN documentation is online there.</p>
+
+<p>Contributions to the FAQ are welcome. Please send them to the project <a
+href="mail.html">mailing list</a>.</p>
+<hr>
+
+<h2><a name="questions">Index of FAQ questions</a></h2>
+<ul>
+  <li><a href="#whatzit">What is FreeS/WAN?</a></li>
+  <li><a href="#problems">How do I report a problem or seek help?</a></li>
+  <li><a href="#generic">Can I get ...</a>
+    <ul>
+      <li><a href="#lemme_out">... an off-the-shelf system that includes
+        FreeS/WAN?</a></li>
+      <li><a href="#contractor">... contractors or staff who know
+        FreeS/WAN?</a></li>
+      <li><a href="#commercial">... commercial support?</a></li>
+    </ul>
+  </li>
+  <li><a href="#release">Release questions</a>
+    <ul>
+      <li><a href="#rel.current">What is the current release?</a></li>
+      <li><a href="#relwhen">When is the next release?</a></li>
+      <li><a href="#rel.bugs">Are there known bugs in the current
+      release?</a></li>
+    </ul>
+  </li>
+  <li><a href="mod_cons">Modifications and contributions</a>
+    <ul>
+      <li><a href="#modify.faq">Can I modify FreeS/WAN to ...?</a></li>
+      <li><a href="#contrib.faq">Can I contribute to the project?</a></li>
+      <li><a href="#ddoc.faq">Is there detailed design documentation?</a></li>
+    </ul>
+  </li>
+  <li><a href="#interact">Will FreeS/WAN work in my environment?</a>
+    <ul>
+      <li><a href="#interop.faq">Can FreeS/WAN talk to ... ?</a></li>
+      <li><a href="#old_to_new">Can different FreeS/WAN versions talk to each
+        other?</a></li>
+      <li><a href="#faq.bandwidth">Is there a limit on throughput?</a></li>
+      <li><a href="#faq.number">Is there a limit on number of
+      connections?</a></li>
+      <li><a href="#faq.speed">Is a ... fast enough to handle FreeS/WAN with
+        my loads?</a></li>
+    </ul>
+  </li>
+  <li><a href="#work_on">Will FreeS/WAN work on ...</a>
+    <ul>
+      <li><a href="#versions">... my version of Linux?</a></li>
+      <li><a href="#nonIntel.faq">... non-Intel CPUs?</a></li>
+      <li><a href="#multi.faq">... multiprocessors?</a></li>
+      <li><a href="#k.old">... an older kernel?</a></li>
+      <li><a href="#k.versions">... the latest kernel version?</a></li>
+      <li><a href="#interface.faq">... unusual network hardware?</a></li>
+      <li><a href="#vlan">... a VLAN (802.1q) network?</a></li>
+    </ul>
+  </li>
+  <li><a href="#features.faq">Does FreeS/WAN support ...</a>
+    <ul>
+      <li><a href="#VPN.faq">... site-to-site VPN applications</a></li>
+      <li><a href="#warrior.faq">... remote users connecting to a LAN</a></li>
+      <li><a href="#road.shared.possible">... remote users using shared
+        secret authentication?</a></li>
+      <li><a href="#wireless.faq">... wireless networks</a></li>
+      <li><a href="#PKIcert">... X.509 or other PKI certificates?</a></li>
+      <li><a href="#Radius">... user authentication (Radius, SecureID,
+        Smart Card ...)?</a></li>
+      <li><a href="#NATtraversal">... NAT traversal</a></li>
+      <li><a href="#virtID">... assigning a "virtual identity" to a remote
+        system?</a></li>
+      <li><a href="#noDES.faq">... single DES encryption?</a></li>
+      <li><a href="#AES.faq">... AES encryption?</a></li>
+      <li><a href="#other.cipher">... other encryption algorithms?</a></li>
+    </ul>
+  </li>
+  <li><a href="#canI">Can I ...</a>
+    <ul>
+      <li><a href="#policy.preconfig">...use policy groups along with 
+         explicitly configured connections?</a></li>
+      <li><a href="#policy.off">...turn off policy groups?</a></li>
+<!--
+      <li><a href="#policy.otherinterface">...use policy groups
+      on an interface other than <VAR>%defaultroute</VAR>?</a></li>
+-->
+      <li><a href="#reload">... reload connection info without
+      restarting?</a></li>
+      <li><a href="#masq.faq">... use several masqueraded subnets?</a></li>
+      <li><a href="#dup_route">... use subnets masqueraded to the same
+        addresses?</a></li>
+      <li><a href="#road.masq">... assign a road warrior an address on my net
+        (a virtual identity)?</a></li>
+      <li><a href="#road.many">... support many road warriors with one
+        gateway?</a></li>
+      <li><a href="#road.PSK">... have many road warriors using shared secret
+        authentication?</a></li>
+      <li><a href="#QoS">... use Quality of Service routing with
+        FreeS/WAN?</a></li>
+      <li><a href="#deadtunnel">... recognise dead tunnels and shut them
+        down?</a></li>
+      <li><a href="#demanddial">... build IPsec tunnels over a demand-dialed
+        link?</a></li>
+      <li><a href="#GRE">... build GRE, L2TP or PPTP tunnels over IPsec?</a></li>
+      <li><a href="#NetBIOS">... use Network Neighborhood (Samba, NetBIOS) over IPsec?</a></li>
+    </ul>
+  </li>
+  <li><a href="#setup.faq">Life's little mysteries</a>
+    <ul>
+      <li><a href="#cantping">I cannot ping ....</a></li>
+      <li><a href="#forever">It takes forever to ...</a></li>
+      <li><a href="#route">I send packets to the tunnel with route(8) but
+        they vanish</a></li>
+      <li><a href="#down_route">When a tunnel goes down, packets
+      vanish</a></li>
+      <li><a href="#firewall_ate">The firewall ate my packets!</a></li>
+      <li><a href="#dropconn">Dropped connections</a></li>
+      <li><a href="#defaultroutegone">Disappearing %defaultroute</a></li>
+      <li><a href="#tcpdump.faq">TCPdump on the gateway shows strange
+        things</a></li>
+      <li><a href="#no_trace">Traceroute does not show anything between the
+        gateways</a></li>
+    </ul>
+  </li>
+  <li><a href="#man4debug">Testing in stages (or .... works but ...
+    doesn't)</a>
+    <ul>
+      <li><a href="#nomanual">Manually keyed connections don't work</a></li>
+      <li><a href="#spi_error">One manual connection works, but second one
+        fails</a></li>
+      <li><a href="#man_no_auto">Manual connections work, but automatic
+        keying doesn't</a></li>
+      <li><a href="#nocomp">IPsec works, but connections using compression
+        fail</a></li>
+      <li><a href="#pmtu.broken">Small packets work, but large transfers
+        fail</a></li>
+      <li><a href="#subsub">Subnet-to-subnet works, but tests from the
+        gateways don't</a></li>
+    </ul>
+  </li>
+  <li><a href="#compile.faq">Compilation problems</a>
+    <ul>
+      <li><a href="#gmp.h_missing">gmp.h: No such file or directory</a></li>
+      <li><a href="#noVM">... virtual memory exhausted</a></li>
+    </ul>
+  </li>
+  <li><a href="#error">Interpreting error messages</a>
+    <ul>
+      <li><a href="#route-client">route-client (or host) exited with status
+        7</a></li>
+      <li><a href="#unreachable">SIOCADDRT:Network is unreachable</a></li>
+      <li><a href="#modprobe">ipsec_setup: modprobe: Can't locate
+        moduleipsec</a></li>
+      <li><a href="#noKLIPS">ipsec_setup: Fatal error, kernel appears to lack
+        KLIPS</a></li>
+      <li><a href="#noDNS">ipsec_setup: ... failure to fetch key for ... from
+        DNS</a></li>
+      <li><a href="#dup_address">ipsec_setup: ... interfaces ... and ...
+        share address ...</a></li>
+      <li><a href="#kflags">ipsec_setup: Cannot adjust kernel flags</a></li>
+      <li><a href="#message_num">Message numbers (MI3, QR1, et cetera) in
+        Pluto messages</a></li>
+      <li><a href="#conn_name">Connection names in Pluto error
+      messages</a></li>
+      <li><a href="#cantorient">Pluto: ... can't orient connection</a></li>
+      <li><a href="#no.interface">... we have no ipsecN interface for either
+        end of this connection</a></li>
+      <li><a href="#noconn">Pluto: ... no connection is known</a></li>
+      <li><a href="#nosuit">Pluto: ... no suitable connection ...</a></li>
+      <li><a href="#noconn.auth">Pluto: ... no connection has been
+        authorized</a></li>
+      <li><a href="#noDESsupport">Pluto: ... OAKLEY_DES_CBC is not
+        supported.</a></li>
+      <li><a href="#notransform">Pluto: ... no acceptable transform</a></li>
+      <li><a href="#rsasigkey">rsasigkey dumps core</a></li>
+      <li><a href="#sig4">!Pluto failure!: ... exited with ... signal
+      4</a></li>
+      <li><a href="#econnrefused">ECONNREFUSED error message</a></li>
+      <li><a href="#no_eroute">klips_debug: ... no eroute!</a></li>
+      <li><a href="#SAused">... trouble writing to /dev/ipsec ... SA already
+        in use</a></li>
+      <li><a href="#ignore">... ignoring ... payload</a></li>
+      <li><a href="#unknown_rightcert">unknown parameter name "rightcert"</a></li> 
+    </ul>
+  <li><a href="#spam">Why don't you restrict the mailing lists to reduce
+    spam?</a></li>
+</ul>
+<hr>
+
+<h2><a name="whatzit">What is FreeS/WAN?</a></h2>
+
+<p>FreeS/WAN is a Linux implementation of the <a
+href="glossary.html#IPSEC">IPsec</a> protocols, providing security services
+at the IP (Internet Protocol) level of the network.</p>
+
+<p>For more detail, see our <a href="intro.html">introduction</a> document or
+the FreeS/WAN project <a href="http://www.freeswan.org/">web site</a>.</p>
+
+<p>To start setting it up, go to our <a href="quickstart.html">quickstart
+guide</a>.</p>
+
+<p>Our <a href="web.html">web links</a> document has information on <a
+href="web.html#implement">IPsec for other systems</a>.</p>
+
+<h2><a name="problems">How do I report a problem or seek help?</a></h2>
+
+<DL>
+<DT>Read our <a href="trouble.html">troubleshooting</a> document.</DT>
+<DD><p>It may guide you to a solution. If not, see its 
+<a href="trouble.html#prob.report">problem reporting</a> section.</p>
+
+<p>Basically, what it says is <strong>give us the output from <var>ipsec
+barf</var> from both gateways</strong>. Without full information, we cannot
+diagnose a problem. However, <var>ipsec barf</var> produces a lot of output.
+If at all possible, <strong>please make barfs accessible via the web or
+FTP</strong> rather than sending enormous mail messages.</p>
+</DD>
+
+<DT><strong>Use the <a href="mail.html">users mailing list</a> for problem
+reports</strong>, rather than mailing developers directly.
+</DT>
+
+<DD>
+<ul>
+  <li>This gives you access to more expertise, including users who may have
+    encountered and solved the same problems.</li>
+  <li>It is more likely to get a quick response. Developers may get behind on
+    email, or even ignore it entirely for a while, but a list message (given
+    a reasonable Subject: line) is certain to be read by a fair number of
+    people within hours.</li>
+  <li>It may also be important because of <a
+    href="politics.html#exlaw">cryptography export laws</a>. A US citizen who
+    provides technical assistance to foreign cryptographic work might be
+    charged under the arms export regulations. Such a charge would be easier
+    to defend if the discussion took place on a public mailing list than if
+    it were done in private mail.</li>
+</ul>
+</DD>
+
+<DT>Try irc.freenode.net#freeswan.</DT>
+
+<DD>
+<p>FreeS/WAN developers, volunteers and users can often be found there. 
+Be patient and be 
+prepared to provide lots of information to support your question.</p>
+
+<p>If your question was really interesting, and you found an answer,
+please share that with the class by posting to the 
+<a href="mail.html">users mailing list</a>. That way others with the
+same problem can find your answer in the archives.</p>
+</DD>
+
+<DT>Premium support is also available.</DT>
+<DD>
+<p>See the next several questions.</p>
+</DD>
+</DL>
+
+<h2><a name="generic">Can I get ...</a></h2>
+
+<h3><a name="lemme_out">Can I get an off-the-shelf system that includes
+FreeS/WAN?</a></h3>
+
+<p>There are a number of Linux distributions or firewall products which
+include FreeS/WAN. See this <a href="intro.html#products">list</a>. Using one
+of these, chosen to match your requirements and budget, may save you
+considerable time and effort.</p>
+
+<p>If you don't know your requirements, start by reading Schneier's <a
+href="biblio.html#secrets">Secrets and Lies</a>. That gives the best overview
+of security issues I have seen. Then consider hiring a consultant (see next
+question) to help define your requirements.</p>
+
+<h3><a name="consultant">Can I hire consultants or staff who know
+FreeS/WAN?</a></h3>
+
+<p>If you want the help of a contractor, or to hire staff with FreeS/WAN
+expertise, you could:</p>
+<ul>
+  <li>check availability in your area through your local Linux User Group (<a
+    href="http://lugww.counter.li.org/">LUG Index</a>)</li>
+  <li>try asking on our <a href="mail.html">mailing list</a></li>
+</ul>
+
+<p>For companies offerring support, see the next question.</p>
+
+<h3><a name="commercial">Can I get commercial support?</a></h3>
+
+<p>Many of the distributions or firewall products which include FreeS/WAN
+(see this <a href="intro.html#products">list</a>) come with commercial
+support or have it available as an option.</p>
+
+<p>Various companies specialize in commercial support of open source
+software. Our project leader was a founder of the first such company, Cygnus
+Support. It has since been bought by <a
+href="http://www.redhat.com">Redhat</a>. Another such firm is <a
+href="http://www.linuxcare.com">Linuxcare</a>.</p>
+
+<h2><a name="release">Release questions</a></h2>
+
+<h3><a name="rel.current">What is the current release?</a></h3>
+
+<p>The current release is the highest-numbered tarball on our <a
+href="ftp://ftp.xs4all.nl/pub/crypto/freeswan">distribution site</a>. Almost
+always, any of <a href="intro.html#mirrors">the mirrors</a> will have the
+same file, though perhaps not for a day or so after a release.</p>
+
+<p>Unfortunately, the web site is not always updated as quickly as it should
+be.</p>
+
+<h3><a name="relwhen">When is the next release?</a></h3>
+
+<p>We try to do a release approximately every six to eight weeks.
+</p>
+
+<p>If pre-release tests fail and the fix appears complex, or more generally
+if the code does not appear stable when a release is scheduled, we will just
+skip that release.</p>
+
+<p>For serious bugs, we may bring out an extra bug-fix release. These get
+numbers in the normal release series.  For example, there was a bug found in
+FreeS/WAN 1.6, so we did another release less than two weeks later. The
+bug-fix release was called 1.7.</p>
+
+<h3><a name="rel.bugs">Are there known bugs in the current release?</a></h3>
+
+<p>Any problems we are aware of at the time of a release are documented in
+the <a href="../BUGS">BUGS</a> file for that release. You should also look at
+the <a href="../CHANGES">CHANGES</a> file.</p>
+
+<p>Bugs discovered after a release are discussed on the <a
+href="mail.html">mailing lists</a>. The easiest way to check for any problems
+in the current code would be to peruse the 
+<a href="http://lists.freeswan.org/pipermail/briefs">List In Brief</a>.</p>
+
+<h2><a name="mod_cons">Modifications and contributions</a></h2>
+
+<h3><a name="modify.faq">Can I modify FreeS/WAN to ...?</a></h3>
+
+<p>You are free to modify FreeS/WAN in any way. See the discussion of <a
+href="intro.html#licensing">licensing</a> in our introduction document.</p>
+
+<p>Before investing much energy in any such project, we suggest that you</p>
+<ul>
+  <li>check the list of <a href="web.html#patch">existing patches</a></li>
+  <li>post something about your project to the <a href="mail.html">design
+    mailing list</a></li>
+</ul>
+
+<p>This may prevent duplicated effort, or lead to interesting
+collaborations.</p>
+
+<h3><a name="contrib.faq">Can I contribute to the project?</a></h3>
+In general, we welcome contributions from the community. Various contributed
+patches, either to fix bugs or to add features, have been incorporated into
+our distribution. Other patches, not yet included in the distribution, are
+listed in our <a href="web.html#patch">web links</a> section.
+
+<p>Users have also contributed heavily to documentation, both by creating
+their own <a href="intro.html#howto">HowTos</a> and by posting things on the
+<a href="mail.html">mailing lists</a> which I have quoted in these HTML
+docs.</p>
+
+<p>There are, however, some caveats.</p>
+
+<p>FreeS/WAN is being implemented in Canada, by Canadians, largely to ensure
+that is it is entirely free of export restrictions. See this <a
+href="politics.html#status">discussion</a>. We <strong>cannot accept code
+contributions from US residents or citizens</strong>, not even one-line bugs
+fixes. The reasons for this were recently discussed extensively on the
+mailing list, in a thread starting <a
+href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/01/msg00111.html">here</a>.</p>
+
+<p>Not all contributions are of interest to us. The project has a set of
+fairly ambitious and quite specific goals, described in our <a
+href="intro.html#goals">introduction</a>. Contributions that lead toward
+these goals are likely to be welcomed enthusiastically. Other contributions
+may be seen as lower priority, or even as a distraction.</p>
+
+<p>Discussion of possible contributions takes place on the <a
+href="mail.html">design mailing list</a>.</p>
+
+<h3><a name="ddoc.faq">Is there detailed design documentation?</a></h3>
+There are:
+<ul>
+  <li><a href="rfc.html">RFCs</a> specifying the protocols we implement</li>
+  <li><a href="manpages.html">man pages</a> for our utilities, library
+    functions and file formats</li>
+  <li>comments in the source code</li>
+  <li><a href="index.html">HTML documentation</a> written primarily for
+  users</li>
+  <li>archived discussions from the <a href="mail.html">mailing lists</a></li>
+  <li>other papers mentioned in our <a
+    href="intro.html#applied">introduction</a></li>
+</ul>
+
+<p>The only formal design documents are a few papers in the last category
+above. All the other categories, however, have things to say about design as
+well.</p>
+
+<h2><a name="interact">Will FreeS/WAN work in my environment?</a></h2>
+
+<h3><a name="interop.faq">Can FreeS/WAN talk to ...?</a></h3>
+
+<p>The IPsec protocols are designed to support interoperation. In theory, any
+two IPsec implementations should be able to talk to each other. In practice,
+it is considerably more complex. We have a whole <a
+href="interop.html">interoperation document</a> devoted to this problem.</p>
+
+<p>An important part of that document is links to the many <a
+href="interop.html#otherpub">user-written HowTos</a> on interoperation
+between FreeS/WAN and various other implementations. Often the users know
+more than the developers about these issues (and almost always more than me
+:-), so these documents may be your best resource.</p>
+
+<h3><a name="old_to_new">Can different FreeS/WAN versions talk to each
+other?</a></h3>
+
+<p>Linux FreeS/WAN can interoperate with many IPsec implementations,
+including earlier versions of Linux FreeS/WAN itself.</p>
+
+<p>In a few cases, there are some complications. See our <a
+href="interop.html#oldswan">interoperation</a> document for details.</p>
+
+<h3><a name="faq.bandwidth">Is there a limit on throughput?</a></h3>
+
+<p>There is no hard limit, but see below.</p>
+
+<h3><a name="faq.number">Is there a limit on number of tunnels?</a></h3>
+
+<p>There is no hard limit, but see next question.</p>
+
+<h3><a name="faq.speed">Is a ... fast enough to handle FreeS/WAN with my
+loads?</a></h3>
+
+<p>A quick summary:</p>
+<dl>
+  <dt>Even a limited machine can be useful</dt>
+    <dd>A 486 can handle a T1, ADSL or cable link, though the machine may be
+      breathing hard.</dd>
+  <dt>A mid-range PC (say 800 MHz with good network cards) can do a lot of
+  IPsec</dt>
+    <dd>With up to roughly 50 tunnels and aggregate bandwidth of 20 Megabits
+      per second, it willl have cycles left over for other tasks.</dd>
+  <dt>There are limits</dt>
+    <dd>Even a high end CPU will not come close to handling a fully loaded
+      100 Mbit/second Ethernet link.
+      <p>Beyond about 50 tunnels it needs careful management.</p>
+    </dd>
+</dl>
+
+<p>See our <a href="performance.html">FreeS/WAN performance</a> document for
+details.</p>
+
+<h2><a name="work_on">Will FreeS/WAN work on ... ?</a></h2>
+
+<h3><a name="versions">Will FreeS/WAN run on my version of Linux?</a></h3>
+
+<p>We build and test on Redhat distributions, but FreeS/WAN runs just fine on
+several other distributions, sometimes with minor fiddles to adapt to the
+local environment. Details are in our <a
+href="compat.html#otherdist">compatibility</a> document. Also, some
+distributions or products come with <a href="intro.html#products">FreeS/WAN
+included</a>.</p>
+
+<h3><a name="nonIntel.faq">Will FreeS/WAN run on non-Intel CPUs?</a></h3>
+
+<p>FreeS/WAN is <strong>intended to run on all CPUs Linux supports</strong>.
+We know of it being used in production on x86, ARM, Alpha and MIPS. It has
+also had successful tests on PPC and SPARC, though we don't know of actual
+use there. Details are in our <a href="compat.html#CPUs">compatibility</a>
+document.</p>
+
+<h3><a name="multi.faq">Will FreeS/WAN run on multiprocessors?</a></h3>
+
+<p>FreeS/WAN is designed to work on any SMP architecture Linux supports, and
+has been tested successfully on at least dual processor Intel architecture
+machines. Details are in our <a
+href="compat.html#multiprocessor">compatibility</a> document.</p>
+
+<h3><a name="k.old">Will FreeS/WAN work on an older kernel?</a></h3>
+
+<p>It might, but we strongly recommend using a recent 2.2 or 2.4 series
+kernel. Sometimes the newer versions include security fixes which can be
+quite important on a gateway.</p>
+
+<p>Also, we use recent kernels for development and testing, so those are
+better tested and, if you do encounter a problem, more easily supported. If
+something breaks applying recent FreeS/WAN patches to an older kernel, then
+"update your kernel" is almost certain to be the first thing we suggest. It
+may be the only suggestion we have.</p>
+
+<p>The precise kernel versions supported by a particular FreeS/WAN release
+are given in the <a href="XX">README</a> file of that release.</p>
+
+<p>See the following question for more on kernels.</p>
+
+<h3><a name="k.versions">Will FreeS/WAN run on the latest kernel
+version?</a></h3>
+
+<p>Sometimes yes, but quite often, no.</p>
+
+<p>Kernel versions supported are given in the <a href="../README">README</a>
+file of each FreeS/WAN release. Typically, they are whatever production
+kernels were current at the time of our release (or shortly before; we might
+release for kernel <var>n</var> just as Linus releases <var>n+1</var>). Often
+FreeS/WAN will work on slightly later kernels as well, but of course this
+cannot be guaranteed.</p>
+
+<p>For example, FreeS/WAN 1.91 was released for kernels 2.2.19 or 2.4.5, the
+current kernels at the time. It also worked on 2.4.6, 2.4.7 and 2.4.8, but
+2.4.9 had changes that caused compilation errors if it was patched with
+FreeS/WAN 1.91.</p>
+
+<p>When such changes appear, we put a fix in the FreeS/WAN snapshots, and
+distribute it with our next release. However, this is not a high priority for
+us, and it may take anything from a few days to several weeks for such a
+problem to find its way to the top of our kernel programmer's To-Do list. In
+the meanwhile, you have two choices:</p>
+<ul>
+  <li>either stick with a slightly older kernel, even if it is not the latest
+    and greatest. This is recommended for production systems; new versions
+    may have new bugs.</li>
+  <li>or fix the problem yourself and send us a patch, via the <a
+    href="mail.html">Users mailing list</a>.</li>
+</ul>
+
+<p>We don't even try to keep up with kernel changes outside the main 2.2 and
+2.4 branches, such as the 2.4.x-ac patched versions from Alan Cox or the 2.5
+series of development kernels. We'd rather work on developing the FreeS/WAN
+code than on chasing these moving targets. We are, however, happy to get
+patches for problems discovered there.</p>
+
+<p>See also the <a href="install.html#choosek">Choosing a kernel</a> section
+of our installation document.</p>
+
+<h3><a name="interface.faq">Will FreeS/WAN work on unusual network
+hardware?</a></h3>
+
+<p>IPsec is designed to work over any network that IP works over, and
+FreeS/WAN is intended to work over any network interface hardware that Linux
+supports.</p>
+
+<p>If you have working IP on some unusual interface -- perhaps Arcnet, Token
+Ring, ATM or Gigabit Ethernet -- then IPsec should "just work".</p>
+
+<p>That said, practice is sometimes less tractable than theory. Our testing
+is done almost entirely on:</p>
+<ul>
+  <li>10 or 100 Mbit Ethernet</li>
+  <li>ADSL or cable connections, with and without PPPoE</li>
+  <li>IEEE 802.11 wireless LANs (see <a href="#wireless.faq">below</a>)</li>
+</ul>
+
+<p>If you have some other interface, especially an uncommon one, it is
+entirely possible you will get bitten either by a FreeS/WAN bug which our
+testing did not turn up, or by a bug in the driver that shows up only with
+our loads.</p>
+
+<p>If IP works on your interface and FreeS/WAN doesn't, seek help on the <a
+href="mail.html">mailing lists</a>.</p>
+
+<p>Another FAQ section describes <a href="#pmtu.broken">MTU problems</a>.
+These are a possibility for some interfaces.</p>
+
+<h3><a name="vlan">Will FreeS/WAN work on a VLAN (802.1q) network?</a></h3>
+
+<p>
+   Yes, FreeSwan works fine, though some network drivers have problems
+   with jumbo sized ethernet frames. If you used interfaces=%defaultroute
+   you do not need to change anything, but if you specified an interface
+   (eg eth0) then remember you must change that to reflect the VLAN
+   interface (eg eth0.2 for VLAN ID 2).
+</p>
+<p>
+   The "eepro100" module is known to be broken, use the e100 driver
+   for those cards instead (included in 2.4 as 'alternative driver' for
+   the Intel EtherExpressPro/100.
+</p>
+<p>
+   You do not need to change any MTU setting (those are workarounds
+   that are only needed for buggy drivers)
+</p>
+
+<p><em>This FAQ contributed by Paul Wouters.</em></p>
+
+<h2><a name="features.faq">Does FreeS/WAN support ...</a></h2>
+
+<p>For a discussion of which parts of the IPsec specifications FreeS/WAN does
+and does not implement, see our <a href="compat.html#spec">compatibility</a>
+document.</p>
+
+<p>For information on some often-requested features, see below.</p>
+
+<h3><a name="VPN.faq"></a>Does FreeS/WAN support site-to-site VPN
+(<A HREF="glossary.html#VPN">Virtual Private Network</A>)
+applications?</h3>
+
+<p>Absolutely. See this FreeS/WAN-FreeS/WAN 
+<A HREF="config.html">configuration example</A>. 
+If only one site is using FreeS/WAN, there may be a relevant HOWTO on our 
+<A HREF="interop.html">interop page</A>.
+</p>
+
+<h3><a name="warrior.faq">Does FreeS/WAN support remote users connecting to a
+LAN?</a></h3>
+
+<p>Yes. We call the remote users "Road Warriors". Check out our 
+FreeS/WAN-FreeS/WAN
+<A HREF="config.html#config.rw">Road Warrior Configuration Example</A>.</P>
+
+<p>If your Road Warrior is a Windows or Mac PC, you may need to 
+install an IPsec implementation on that machine. 
+Our <A HREF="interop.html">interop</A> page lists many available brands, 
+and features links to several HOWTOs.
+
+
+<h3><a name="road.shared.possible">Does FreeS/WAN support remote users using
+shared secret authentication?</a></h3>
+
+<p><strong>Yes, but</strong> there are severe restrictions, so <strong>we
+strongly recommend using </strong><a
+href="glossary.html#RSA"><strong>RSA</strong></a><strong> keys for
+</strong> <a
+href="glossary.html#authentication"><strong>authentication</strong></a>
+<strong>
+instead</strong>.</p>
+
+<p>See this <a href="#road.PSK">FAQ question</a>.</p>
+
+<h3><a name="wireless.faq">Does FreeS/WAN support wireless networks?</a></h3>
+
+<p>Yes, it is a common practice to use IPsec over wireless networks because
+their built-in encryption, <a href="glossary.html#WEP">WEP</a>, is
+insecure.</p>
+
+<p>There is some <a href="adv_config.html#wireless.config">discussion</a> in
+our advanced configuration document. See also the 
+<A HREF="http://www.wavesec.org">WaveSEC site</A>.</p>
+
+<h3><a name="PKIcert">Does FreeS/WAN support X.509 or other PKI
+certificates?</a></h3>
+
+<P>Vanilla FreeS/WAN does not support X.509, but Andreas Steffen 
+and others have provided a popular, well-supported X.509 patch.</P>
+
+<UL>
+<LI><A HREF="http://www.strongsec.com/freeswan">patch</A>
+</LI>
+<LI><A HREF="http://www.freeswan.ca">Super FreeS/WAN</A> incorporates
+this and other user-contributed patches.
+</LI>
+<LI>
+Kai Martius' <A HREF="http://www.strongsec.com/freeswan/install.htm">X.509 
+Installation and Configuration Guide</A>
+</LI>
+</UL>
+
+<P>
+Linux FreeS/WAN features
+<A HREF="quickstart.html">Opportunistic Encryption</A>, an alternative
+Public Key Infrastructure based on Secure DNS.
+</P>
+
+<h3><a name="Radius">Does FreeS/WAN support user authentication (Radius,
+SecureID, Smart Card...)?</a></h3>
+
+<P>Andreas Steffen's <A HREF="http://www.strongsec.com/freeswan">X.509 patch</A> (v. 1.42+) supports Smart Cards. The patch
+does not ship with vanilla FreeS/WAN, but will be incorporated into 
+<A HREF="http://www.freeswan.ca/">Super FreeS/WAN 
+2.01+</A>. The patch implements the PCKS#15 
+Cryptographic Token Information Format Standard, using the OpenSC smartcard 
+library functions.</P>
+
+<P>Older news:</P>
+ 
+<P>A user-supported patch to FreeS/WAN 1.3, for smart card style 
+authentication, is available on
+<A HREF="http://alcatraz.webcriminals.com/~bastiaan/ipsec">Bastiaan's site</A>.
+It supports skeyid and ibutton.
+This patch is not part of Super FreeS/WAN.</p>
+
+<p>For a while progress on this front was impeded by a lack of standard.
+The IETF <a
+href="http://www.ietf.org/html.charters/ipsra-charter.html">working group</a>
+has now nearly completed its recommended solution to the problem; meanwhile 
+several vendors have implemented various things.</p>
+
+<!--
+<p>The <a href="web.html#patch">patches</a> section of our web links document
+has links to some user work on this.</p>
+-->
+
+<p>Of course, there are various ways to avoid any requirement for user
+authentication in IPsec. Consider the situation where road warriors build
+IPsec tunnels to your office net and you are considering requiring user
+authentication during tunnel negotiation. Alternatives include:</p>
+<ul>
+  <li>If you can trust the road warrior machines, then set them up so that
+    only authorised users can create tunnels. If your road warriors use
+    laptops, consider the possibility of theft.</li>
+  <li>If the tunnel only provides access to particular servers and you can
+    trust those servers, then set the servers up to require user
+    authentication.</li>
+</ul>
+
+<p>If either of those is trustworthy, it is not clear that you need user
+authentication in IPsec.</p>
+
+
+<h3><a name="NATtraversal">Does FreeS/WAN support NAT traversal?</a></h3>
+
+<p>Vanilla FreeS/WAN does not, but thanks to Mathieu Lafon and
+Arkoon Network Security, there's a patch to support this.</P>
+
+<UL>
+<LI><A HREF="http://open-source.arkoon.net">patch and documentation</A>
+</LI>
+<LI><A HREF="http://www.freeswan.ca">Super FreeS/WAN</A> incorporates
+this and other user-contributed patches.
+</LI>
+</UL>
+
+<P>The NAT traversal patch has some issues with PSKs, so you may wish to 
+authenticate with RSA keys, or X.509 (requires a patch which is also 
+included in Super FreeS/WAN). Doing the latter also has
+advantages when dealing with large numbers of clients who may be behind NAT;
+instead of having to make an individual Roadwarrior connection for each
+virtual IP, you can use the "rightsubnetwithin" parameter to specify a range.
+See
+<A HREF="http://www.strongsec.com/freeswan/install.htm#section_4.4">these
+<VAR>rightsubnetwithin</VAR> instructions</A>.
+</P>
+
+
+<h3><a name="virtID">Does FreeS/WAN support assigning a "virtual identity" to
+a remote system?</a></h3>
+
+<p>Some IPsec implementations allow you to make the source address on packets
+sent by a Road Warrior machine be something other than the address of its
+interface to the Internet. This is sometimes described as assigning a virtual
+identity to that machine.</p>
+
+<p>FreeS/WAN does not directly support this, but it can be done. See this <a
+href="#road.masq">FAQ question</a>.</p>
+
+<h3><a name="noDES.faq">Does FreeS/WAN support single DES encryption?</a></h3>
+
+<p><strong>No</strong>, single DES is not used either at the <a
+href="glossary.html#IKE">IKE</a> level for negotiating connections or at the
+<a href="glossary.html#IPsec">IPsec</a> level for actually building them.</p>
+
+<p>Single DES is <a href="politics.html#desnotsecure">insecure</a>. As we see
+it, it is more important to deliver real security than to comply with a
+standard which has been subverted into allowing use of inadequate methods.
+See this <a href="politics.html#weak">discussion</a>.</p>
+
+<p>If you want to interoperate with an IPsec implementation which offers only
+DES, see our <a href="interop.html#noDES">interoperation</a> document.</p>
+
+<h3><a name="AES.faq">Does FreeS/WAN support AES encryption?</a></h3>
+
+<p><a href="glossary.html#AES">AES</a> is a new US government <a
+href="glossary.html#block">block cipher</a> standard to replace the obsolete
+<a href="glossary.html#DES">DES</a>.</p>
+
+<p>At time of writing (March 2002), the FreeS/WAN distribution does not yet
+support AES but user-written <a href="web.html#patch">patches</a> are
+available to add it. Our kernel programmer is working on integrating those
+patches into the distribution, and there is active discussion of this on the
+design mailimg list.</p>
+
+<h3><a name="other.cipher">Does FreeS/WAN support other encryption
+algorithms?</a></h3>
+
+<p>Currently <a href="glossary.html#3DES">triple DES</a> is the only cipher
+supported. AES will almost certainly be added (see previous question), and it
+is likely that in the process we will also add the other two AES finalists
+with open licensing, Twofish and Serpent.</p>
+
+<p>We are extremely reluctant to add other ciphers. This would make both use
+and maintenance of FreeS/WAN more complex without providing any clear
+benefit. Complexity is emphatically not desirable in a security product.</p>
+
+<p>Various users have written patches to add other ciphers. We provide <a
+href="web.html#patch">links</a> to these.</p>
+
+<h2><a name="canI">Can I ...</a></h2>
+
+
+<h3><a name="policy.preconfig">Can I use policy groups along with
+explicitly configured connections?</a></h3>
+
+<p>Yes, you can, so long as you pay attention to the selection rule, 
+which can be summarized "the most specific 
+connection wins". We describe the rule in our
+<A HREF="policygroups.html#policy.group.notes">policy groups</A> document,
+and provide a more technical explanation in 
+<A HREF="manpage.d/ipsec.conf.5.html">man ipsec.conf</A>.
+</p>
+
+<p>A good guideline: If you have a regular connection defined in 
+<VAR>ipsec.conf</VAR>, ensure that a subset of that connection
+is not listed in a less restrictive policy group. Otherwise, 
+FreeS/WAN will use the subset, with its more specific source/destination 
+pair.</p>
+
+<p>Here's an example. Suppose you are the system administrator at 192.0.2.2.
+You have this connection in ipsec.conf:
+<VAR>ipsec.conf</VAR>:
+
+<PRE>conn net-to-net
+    left=192.0.2.2           # you are here
+    right=192.0.2.8
+    rightsubnet=192.0.2.96/27
+    ....
+</PRE>
+
+<p>If you then place a host or net within <VAR>rightsubnet</VAR>, 
+(let's say 192.0.2.98) in <VAR>private-or-clear</VAR>, you may find 
+that 192.0.2.2 at times communicates in the
+clear with 192.0.2.98. That's consistent with the rule, but may be 
+contrary to your expectations.</p>
+
+<p>On the other hand, it's safe to put a larger subnet in a less
+restrictive policy group file. If <VAR>private-or-clear</VAR>
+contains 192.0.2.0/24, then the more specific <VAR>net-to-net</VAR>
+connection is used for any communication to 192.0.2.96/27. The
+more general policy applies only to communication with hosts or subnets in 
+192.0.2.0/24 without a more specific policy or connection.</p>
+
+
+<h3><a name="policy.off">Can I turn off policy groups?</a></h3>
+
+<p>Yes. Use <A HREF="policygroups.html#disable_policygroups">these
+instructions</A>.</p>
+
+<!--
+<h3><a name="policy.otherinterface">Can I use policy groups
+ on an interface other than <VAR>%defaultroute</VAR>?</a></h3>
+
+<p>??<p>
+-->
+
+<h3><a name="reload">Can I reload connection info without restarting?</a></h3>
+
+<p>Yes, you can do this. Here are the details, in a mailing list message from
+Pluto programmer Hugh Redelmeier:</p>
+<pre>| How can I reload config's without restarting all of pluto and klips?  I am using
+| FreeSWAN -&gt; PGPNet in a medium sized production environment, and would like to be
+| able to add new connections ( i am using include config/* ) without dropping current
+| SA's.
+| 
+| Can this be done?
+| 
+| If not, are there plans to add this kind of feature?
+
+        ipsec auto --add whatever
+This will look in the usual place (/etc/ipsec.conf) for a conn named
+whatever and add it.
+
+If you added new secrets, you need to do
+        ipsec auto --rereadsecrets
+before Pluto needs to know those secrets.
+
+| I have looked (perhaps not thoroughly enough tho) to see how to do this:
+
+There may be more bits to look for, depending on what you are trying
+to do.</pre>
+
+<p>Another useful command here is <var>ipsec auto --replace
+&lt;conn_name&gt;</var> which re-reads data for a named connection.</p>
+
+<h3><a name="masq.faq">Can I use several masqueraded subnets?</a></h3>
+
+<p>Yes. This is done all the time. See the discussion in our <a
+href="config.html#route_or_not">setup</a> document. The only restriction is
+that the subnets on the two ends must not overlap. See the next question.</p>
+
+<p>Here is a mailing list message on the topic. The user incorrectly thinks
+you need a 2.4 kernel for this -- actually various people have been doing it
+on 2.0 and 2.2 for quite some time -- but he has it right for 2.4.</p>
+<pre>Subject: Double NAT and freeswan working :)
+   Date: Sun, 11 Mar 2001
+   From: Paul Wouters &lt;paul@xtdnet.nl&gt;
+
+Just to share my pleasure, and make an entry for people who are searching
+the net on how to do this. Here's the very simple solution to have a double
+NAT'ed network working with freeswan. (Not sure if this is old news, but I'm
+not on the list (too much spam) and I didn't read this in any HOWTO/FAQ/doc
+on the freeswan site yet (Sandy, put it in! :)
+
+10.0.0.0/24 --- 10.0.0.1 a.b.c.d  ---- a.b.c.e {internet} ----+
+                                                              |
+10.0.1.0/24 --- 10.0.1.1 f.g.h.i  ---- f.g.h.j {internet} ----+
+
+the goal is to have the first network do a VPN to the second one, yet also
+have NAT in place for connections not destinated for the other side of the
+NAT. Here the two Linux security gateways have one real IP number (cable
+modem, dialup, whatever.
+
+The problem with NAT is you don't want packets from 10.*.*.* to 10.*.*.*
+to be NAT'ed. While with Linux 2.2, you can't, with Linux 2.4 you can.
+
+(This has been tested and works for 2.4.2 with Freeswan snapshot2001mar8b)
+
+relevant parts of /etc/ipsec.conf:
+
+        left=f.g.h.i
+        leftsubnet=10.0.1.0/24
+        leftnexthop=f.g.h.j
+        leftfirewall=yes
+        leftid=@firewall.netone.nl
+        leftrsasigkey=0x0........
+        right=a.b.c.d
+        rightsubnet=10.0.0.0/24
+        rightnexthop=a.b.c.e
+        rightfirewall=yes
+        rightid=@firewall.nettwo.nl
+        rightrsasigkey=0x0......
+        # To authorize this connection, but not actually start it, at startup,
+        # uncomment this.
+        auto=add
+
+and now the real trick. Setup the NAT correctly on both sites:
+
+iptables -t nat -F
+iptables -t nat -A POSTROUTING -o eth0 -d \! 10.0.0.0/8 -j MASQUERADE
+
+This tells the NAT code to only do NAT for packets with destination other then
+10.* networks. note the backslash to mask the exclamation mark to protect it
+against the shell.
+
+Happy painting :)
+
+Paul</pre>
+
+<h3><a name="dup_route">Can I use subnets masqueraded to the same
+addresses?</a></h3>
+
+<p><strong>No.</strong> The notion that IP addresses are unique is one of the
+fundamental principles of the IP protocol. Messing with it is exceedingly
+perilous.</p>
+
+<p>Fairly often a situation comes up where a company has several branches,
+all using the same <a href="glossary.html#non-routable">non-routable
+addresses</a>, perhaps 192.168.0.0/24. This works fine as long as those nets
+are kept distinct. The <a href="glossary.html#masq">IP masquerading</a> on
+their firewalls ensures that packets reaching the Internet carry the firewall
+address, not the private address.</p>
+
+<p>This can break down when IPsec enters the picture. FreeS/WAN builds a
+tunnel that pokes through both masquerades and delivers packets from
+<var>leftsubnet</var> to <var>rightsubnet</var> and vice versa. For this to
+work, the two subnets <em>must</em> be distinct.</p>
+
+<p>There are several solutions to this problem.</p>
+
+<p>Usually, you <strong>re-number the subnets</strong>. Perhaps the Vancouver
+office becomes 192.168.101.0/24, Calgary 192.168.102.0/24 and so on.
+FreeS/WAN can happily handle this. With, for example
+<var>leftsubnet=192.168.101.0/24</var> and
+<var>rightsubnet=192.168.102.0/24</var> in a connection description, any
+machine in Calgary can talk to any machine in Vancouver. If you want to be
+more restrictive and use something like
+<var>leftsubnet=192.168.101.128/25</var> and
+<var>rightsubnet=192.168.102.240/28</var> so only certain machines on each
+end have access to the tunnel, that's fine too.</p>
+
+<p>You could also <strong>split the subnet</strong> into smaller ones, for
+example using <var>192.168.1.0/25</var> in Vancouver and
+<var>rightsubnet=192.168.0.128/25</var> in Calgary.</p>
+
+<p>Alternately, you can just <strong>give up routing</strong> directly to
+machines on the subnets. Omit the <var>leftsubnet</var> and
+<var>rightsubnet</var> parameters from your connection descriptions. Your
+IPsec tunnels will then run between the public interfaces of the two
+firewalls. Packets will be masqueraded both before they are put into tunnels
+and after they emerge. Your Vancouver client machines will see only one
+Calgary machine, the firewall.</p>
+
+<h3><a name="road.masq">Can I assign a road warrior an address on my net (a
+virtual identity)?</a></h3>
+
+<p>Often it would be convenient to be able to give a Road Warrior an IP
+address which appears to be on the local network. Some IPsec implementations
+have support for this, sometimes calling the feature "virtual identity".</p>
+
+<p>Currently (Sept 2002) FreeS/WAN does not support this, and we have
+no definite plans to add it. The difficulty is that is not yet a standard
+mechanism for it. There is an Internet Draft for a method of doing it using
+<a href="#DHCP">DHCP</a> which looks promising. FreeS/WAN may support that in
+a future release.</p>
+
+<p>In the meanwhile, you can do it yourself using the Linux iproute2(8)
+facilities. Details are in <a
+href="http://www.av8n.com/vpn/iproute2.htm">this
+paper</a>.</p>
+
+<p>Another method has also been discussed on the mailing list.:</p>
+<ul>
+  <li>You can use a variant of the <a
+    href="adv_config.html#extruded.config">extruded subnet</a> procedure.</li>
+  <li>You have to avoid having the road warrior's assigned address within the
+    range you actually use at home base. See previous question.</li>
+  <li>On the other hand, you want the roadwarrior's address to be within the
+    range that <em>seems</em> to be on your network.</li>
+</ul>
+
+<p>For example, you might have:</p>
+<dl>
+  <dt>leftsubnet=a.b.c.0/25</dt>
+    <dd>head office network</dd>
+  <dt>rightsubnet=a.b.c.129/32</dt>
+    <dd>extruded to a road warrior. Note that this is not in a.b.c.0/25</dd>
+  <dt>a.b.c.0/24</dt>
+    <dd>whole network, including both the above</dd>
+</dl>
+
+<p>You then set up routing so that the office machines use the IPsec gateway
+as their route to a.b.c.128/25. The leftsubnet parameter tells the road
+warriors to use tunnels to reach a.b.c.0/25, so you should have two-way
+communication. Depending or your network and applications, there may be some
+additional work to do on DNS or Windows configuration</p>
+
+<h3><a name="road.many">Can I support many road warriors with one
+gateway?</a></h3>
+
+<p>Yes. This is easily done, using</p>
+<dl>
+  <dt>either RSA authentication</dt>
+    <dd>standard in the FreeS/WAN distribution</dd>
+  <dt>or X.509 certificates</dt>
+    <dd>requires <a href="#PKIcert">Super FreeS/WAN or a patch</a>.</dd>
+</dl>
+
+<p>In either case, each Road Warrior must have a different key or
+certificate.</p>
+
+<p>It is also possible using pre-shared key authentication,
+though we don't recommend this; see the
+<a href="#road.PSK">next question</a> for details.</p>
+
+<p>If you expect to have more than a few dozen Road Warriors connecting
+simultaneously, you may need a fairly powerful gateway machine. See our
+document on <a href="performance.html">FreeS/WAN performance</a>.</p>
+
+<h3><a name="road.PSK">Can I have many road warriors using shared secret
+authentication?</a></h3>
+
+<p><STRONG>Yes, but avoid it if possible</STRONG>.</p>
+
+<p>You can have multiple Road Warriors using shared secret authentication
+<strong>only if they all use the same secret</strong>. You must also 
+set:<p>
+
+<PRE>   uniqueids=no   </PRE>
+
+<p>in the connection definition.</p>
+
+
+<p>Why it's less secure:</p>
+<ul>
+  <li>If you have many users, it becomes almost certain the secret will
+  leak</li>
+  <li>The secret becomes quite valuable to an attacker</li>
+  <li>All users authenticate the same way, so the gateway cannot tell them
+    apart for logging or access control purposes</li>
+  <li>Changing the secret is difficult. You have to securely notify all
+  users.</li>
+  <li>If you find out the secret has been compromised, you can change it, but
+    then what? None of your users can connect without the new secret. How
+    will you notify them all, quickly and securely, without using the
+  VPN?</li>
+</ul>
+
+<p>This is a designed-in limitation of the <a
+href="glossary.html#IKE">IKE</a> key negotiation protocol, not a problem with
+our implementation.</p>
+
+<p><strong>We very strongly recommend that you avoid using shared secret
+authentication for multiple Road Warriors.</strong> Use RSA authentication
+instead.</p>
+
+<p>The longer story: When using shared secrets, the protocol requires 
+that the responding
+gateway be able to determine which secret to use at a time when all it knows
+about the initiator is an IP address. This works fine if you know the
+initiator's address in advance and can use it to look up the appropiriate
+secret. However, it fails for Road Warriors since the gateway cannot know
+their IP addresses in advance.</p>
+
+<p>With RSA signatures (or certificates) the protocol is slightly different.
+The initiator provides an identifier early in the exchange and the responder
+can use that identifier to look up the correct key or certificate. See <a
+href="#road.many">above</a>.</p>
+
+<h3><a name="QoS">Can I use Quality of Service routing with
+FreeS/WAN?</a></h3>
+
+<p>From project technical lead Henry Spencer:</p>
+<pre>&gt; Do QoS add to FreeS/WAN?
+&gt; For example integrating DiffServ and FreeS/WAN?
+
+With a current version of FreeS/WAN, you will have to add hidetos=no to
+the config-setup section of your configuration file.  By default, the TOS
+field of tunnel packets is zeroed; with hidetos=no, it is copied from the
+packet inside.  (This is a modest security hole, which is why it is no
+longer the default.)
+
+DiffServ does not interact well with tunneling in general.  Ways of
+improving this are being studied.</pre>
+
+<p>Copying the <a href="glossary.html#TOS">TOS</a> (type of service)
+information from the encapsulated packet to the outer header reveals the TOS
+information to an eavesdropper. This does not tell him much, but it might be
+of use in <a href="glossary.html#traffic">traffic analysis</a>. Since we do
+not have to give it to him, our default is not to.</p>
+
+<P>Even with the TOS hidden, you can still:</P>
+<UL>
+<LI>apply QOS rules to the tunneled (ESP) packets; for example, by
+giving ESP packets a certain priority.</LI>
+<LI>apply QOS rules to the packets as they enter or exit the tunnel
+via an IPsec virtual interface (eg. <VAR>ipsec0</VAR>).</LI>
+</UL>
+
+<p>See <a href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a> for more on
+the <var>hidetos=</var> parameter.</p>
+
+
+<h3><a name="deadtunnel">Can I recognise dead tunnels and shut them
+down?</a></h3>
+
+<p>There is no general mechanism to do this is in the IPsec protocols.</p>
+
+<p>From time to time, there is discussion on the IETF Working Group <a
+href="mail.html#ietf">mailing list</a> of adding a "keep-alive" mechanism
+(which some say should be called "make-dead"), but it is a fairly complex
+problem and no consensus has been reached on whether or how it should be
+done.</p>
+
+<p>The protocol does have optional <a href="#ignore">delete-SA</a> messages
+which one side can send when it closes a connection in hopes this will cause
+the other side to do the same. FreeS/WAN does not currently support these. In
+any case, they would not solve the problem since:</p>
+<ul>
+  <li>a gateway that crashes or hangs would not send the messages</li>
+  <li>the sender is not required to send them</li>
+  <li>they are not authenticated, so any receiver that trusts them leaves
+    itself open to a <a href="glossary.html#DOS">denial of service</a>
+  attack</li>
+  <li>the receiver is not required to do anything about them</li>
+  <li>the receiver cannot acknowledge them; the protocol provides no
+    mechanism for that</li>
+  <li>since they are not acknowledged, the sender cannot rely on them</li>
+</ul>
+
+<p>However, connections do have limited lifetimes and you can control how
+many attempts your gateway makes to rekey before giving up. For example, you
+can set:</p>
+<pre>conn default
+        keyingtries=3
+        keylife=30m</pre>
+
+<p>With these settings old connections will be cleaned up. Within 30 minutes
+of the other end dying, rekeying will be attempted. If it succeeds, the new
+connection replaces the old one. If it fails, no new connection is created.
+Either way, the old connection is taken down when its lifetime expires.</p>
+
+<p>Here is a mailing list message on the topic from FreeS/WAN tech support
+person Claudia Schmeing:</p>
+<pre>You ask how to determine whether a tunnel is redundant:
+
+&gt; Can anybody explain the best way to determine this. Esp when a RW has
+&gt; disconnected? I thought 'ipsec auto --status' might be one way.
+
+If a tunnel goes down from one end, Linux FreeS/WAN on the
+other end has no way of knowing this until it attempts to rekey.
+Once it tries to rekey and fails, it will 'know' that the tunnel is 
+down.
+
+Because it doesn't have a way of knowing the state until this point, 
+it will also not be able to tell you the state via ipsec auto --status.
+
+&gt; However, comparing output from a working tunnel with that of one that
+&gt; was closed 
+&gt; did not show clearly show tunnel status.
+
+If your tunnel is down but not 'unrouted' (see man ipsec_auto), you
+should not be able to ping the opposite side of the tunnel. You can
+use this as an indicator of tunnel status.
+
+On a related note, you may be interested to know that as of 1.7, 
+redundant tunnels caused by RW disconnections are likely to be 
+less of a pain. From doc/CHANGES:
+
+    There is a new configuration parameter, uniqueids, to control a new Pluto
+    option:  when a new connection is negotiated with the same ID as an old
+    one, the old one is deleted immediately.  This should help eliminate
+    dangling Road Warrior connections when the same Road Warrior reconnects. 
+    It thus requires that IDs not be shared by hosts (a previously legal but
+    probably useless capability).  NOTE WELL:  the sample ipsec.conf now has
+    uniqueids=yes in its config-setup section.
+
+
+Cheers,
+
+Claudia</pre>
+
+<h3><a name="demanddial">Can I build IPsec tunnels over a demand-dialed
+link?</a></h3>
+
+<p>This is possible, but not easy. FreeS/WAN technical lead Henry Spencer
+wrote:</p>
+<pre>&gt; 5. If the ISDN link goes down in between and is reestablished, the SAs
+&gt; are still up but the eroute are deleted and the IPsec interface shows
+&gt; garbage (with ifconfig)
+&gt; 6. Only restarting IPsec will bring the VPN back online.
+
+This one is awkward to solve.  If the real interface that the IPsec
+interface is mounted on goes down, it takes most of the IPsec machinery
+down with it, and a restart is the only good way to recover. 
+
+The only really clean fix, right now, is to split the machines in two: 
+
+1. A minimal machine serves as the network router, and only it is aware
+that the link goes up and down. 
+
+2. The IPsec is done on a separate gateway machine, which thinks it has
+a permanent network connection, via the router.
+
+This is clumsy but it does work.  Trying to do both functions within a
+single machine is tricky.  There is a software package (diald) which will
+give the illusion of a permanent connection for demand-dialed modem
+connections; I don't know whether it's usable for ISDN, or whether it can
+be made to cooperate properly with FreeS/WAN. 
+
+Doing a restart each time the interface comes up *does* work, although it
+is a bit painful.  I did that with PPP when I was running on a modem link;
+it wasn't hard to arrange the PPP scripts to bring IPsec up and down at
+the right times.  (I'd meant to investigate diald but never found time.)
+
+In principle you don't need to do a complete restart on reconnect, but you
+do have to rebuild some things, and we have no nice clean way of doing
+only the necessary parts.</pre>
+
+<p>In the same thread, one user commented:</p>
+<pre>Subject: Re: linux-ipsec: IPsec and Dial Up Connections
+   Date: Wed, 22 Nov 2000
+   From: Andy Bradford &lt;andyb@calderasystems.com&gt;
+
+On Wed, 22 Nov 2000 19:47:11 +0100, Philip Reetz wrote:
+
+&gt; Are there any ideas what might be the cause of the problem and any way
+&gt; to work around it.
+&gt; Any help is highly appreciated.
+
+On my laptop, when using ppp there is a ip-up script in /etc/ppp that 
+will be executed each time that the ppp interface is brought up.  
+Likewise there is an ip-down script that is called when it is taken 
+down.  You might consider custimzing those to stop and start FreeS/WAN 
+with each connection.  I believe that ISDN uses the same files, though 
+I could be wrong---there should be something similar though.</pre>
+
+<h3><a name="GRE">Can I build GRE, L2TP or PPTP tunnels over IPsec?</a></h3>
+
+<p>Yes. Normally this is not necessary, but it is useful in a few special
+cases. For example, if you must route non-IP packets such as IPX, you
+will need to use a tunneling protocol that can route these packets. IPsec
+can be layered around it for extra security. Another example: you 
+can provide failover protection for high availability (HA) environments by
+combining IPsec with other tools. Ken Bantoft describes one such setup in 
+<A HREF="http://www.freeswan.ca/docs/HA">Using FreeS/WAN with Linux-HA, GRE, 
+OSPF and BGP for enterprise grade VPN solutions</A>.</P>
+
+<p>GRE over IPsec is covered as part of 
+<A HREF="http://www.freeswan.ca/docs/HA">that document</A>. 
+<a href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/07/msg00209.html">
+Here are links</a> to other GRE resources.
+
+Jacco de Leuw has created
+<A HREF="http://www.jacco2.dds.nl/networking/">this page on L2TP over IPsec</A> 
+with instructions for FreeS/WAN and several other brands of IPsec software.
+</P>
+
+<P>Please let us know of other useful links via the
+<A HREF="mail.html">mailing lists</A>.
+
+
+<h3><a name="NetBIOS">... use Network Neighborhood (Samba, NetBIOS) over IPsec?</a></h3>
+
+<p>Your local PC needs to know how to translate NetBIOS names to IP addresses.
+It may do this either via a local LMHOSTS file, or using a local or remote
+WINS server. The WINS server is preferable since it provides a centralized
+source of the information to the entire network. To use a WINS server over 
+the <A HREF="glossary.html#VPN">VPN</A>
+(or any IP-based network), you must enable "NetBIOS over TCP".</p>
+
+<p><A HREF="http://www.samba.org">Samba</A> can emulate a WINS server
+on Linux.</p>
+
+<p>
+See also several discussions in our 
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-September/thread.html">September 
+2002 Users archives</A></p>
+
+
+<h2><a name="setup.faq">Life's little mysteries</a></h2>
+
+<p>FreeS/WAN is a fairly complex product. (Neither the networks it runs on
+nor the protocols it uses are simple, so it could hardly be otherwise.) It
+therefore sometimes exhibits behaviour which can be somewhat confusing, or
+has problems which are not easy to diagnose. This section tries to explain
+those problems.</p>
+
+<p>Setup and configuration of FreeS/WAN are covered in other documentation
+sections:</p>
+<ul>
+  <li><a href="quickstart.html">basic setup and configuration</a></li>
+  <li><a href="adv_config.html">advanced configuration</a></li>
+  <li><a href="trouble.html">Troubleshooting</a></li>
+</ul>
+
+<p>However, we also list some of the commonest problems here.</p>
+
+<h3><a name="cantping">I cannot ping ....</a></h3>
+
+<p>This question is dealt with in the advanced configuration section under
+the heading <a href="adv_config.html#multitunnel">multiple tunnels</a>.</p>
+
+<p>The standard subnet-to-subnet tunnel protects traffic <strong>only between
+the subnets</strong>. To test it, you must use pings that go from one subnet
+to the other.</p>
+
+<p>For example, suppose you have:</p>
+<pre>      subnet a.b.c.0/24
+             |
+      eth1 = a.b.c.1
+         gate1
+      eth0 = 192.0.2.8
+             |
+
+       ~ internet ~
+
+             |
+      eth0 = 192.0.2.11
+         gate2
+      eth1 = x.y.z.1
+              |
+       subnet x.y.z.0/24</pre>
+
+<p>and the connection description:</p>
+<pre>conn abc-xyz
+     left=192.0.2.8
+     leftsubnet=a.b.c.0/24
+     right=192.0.2.11
+     rightsubnet=x.y.z.0/24</pre>
+
+<p>You can test this connection description only by sending a ping that will
+actually go through the tunnel. Assuming you have machines at addresses
+a.b.c.2 and x.y.z.2, pings you might consider trying are:</p>
+<dl>
+  <dt>ping from x.y.z.2 to a.b.c.2 or vice versa</dt>
+    <dd>Succeeds if tunnel is working. This is the <strong>only valid test of
+      the tunnel</strong>.</dd>
+  <dt>ping from gate2 to a.b.c.2 or vice versa</dt>
+    <dd><strong>Does not use tunnel</strong>. gate2 is not on protected
+      subnet.</dd>
+  <dt>ping from gate1 to x.y.z.2 or vice versa</dt>
+    <dd><strong>Does not use tunnel</strong>. gate1 is not on protected
+      subnet.</dd>
+  <dt>ping from gate1 to gate2 or vice versa</dt>
+    <dd><strong>Does not use tunnel</strong>. Neither gate is on a protected
+      subnet.</dd>
+</dl>
+
+<p>Only the first of these is a useful test of this tunnel. The others do not
+use the tunnel. Depending on other details of your setup and routing,
+they:</p>
+<ul>
+  <li>either fail, telling you nothing about the tunnel</li>
+  <li>or succeed, telling you nothing about the tunnel since these packets
+    use some other route</li>
+</ul>
+
+<p>In some cases, you may be able to get around this. For the example network
+above, you could use:</p>
+<pre>        ping -I a.b.c.1 x.y.z.1</pre>
+
+<p>Both the adresses given are within protected subnets, so this should go
+through the tunnel.</p>
+
+<p>If required, you can build additional tunnels so that all the machines
+involved can talk to all the others. See <a
+href="adv_config.html#multitunnel">multiple tunnels</a> in the advanced
+configuration document for details.</p>
+
+<h3><a name="forever">It takes forever to ...</a></h3>
+
+<p>Users fairly often report various problems involving long delays,
+sometimes on tunnel setup and sometimes on operations done through the
+tunnel, occasionally on simple things like ping or more often on more complex
+operations like doing NFS or Samba through the tunnel.</p>
+
+<p>Almost always, these turn out to involve failure of a DNS lookup. The
+timeouts waiting for DNS are typically set long so that you won't time out
+when a query involves multiple lookups or long paths. Genuine failures
+therefore produce long delays before they are detected.</p>
+
+<p>A mailing list message from project technical lead Henry Spencer:</p>
+<pre>&gt; ... when i run /etc/rc.d/init.d/ipsec start, i get:
+&gt; ipsec_setup: Starting FreeS/WAN IPsec 1.5...
+&gt; and it just sits there, doesn't give back my bash prompt.
+
+Almost certainly, the problem is that you're using DNS names in your
+ipsec.conf, but DNS lookups are not working for some reason.  You will
+get your prompt back... eventually.  But the DNS timeouts are long.
+Doing something about this is on our list, but it is not easy.</pre>
+
+<p>In the meanwhile, we recommend that connection descriptions in <a
+href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a> use numeric IP addresses
+rather than names which will require a DNS lookup.</p>
+
+<p>Names that do not require a lookup are fine. For example:</p>
+<ul>
+  <li>a road warrior might use the identity
+    <var>rightid=@lancelot.example.org</var></li>
+  <li>the gateway might use <var>leftid=@camelot.example.org</var></li>
+</ul>
+
+<p>These are fine. The @ sign prevents any DNS lookup. However, do not
+attempt to give the gateway address as <var>left=camelot.example.org</var>.
+That requires a lookup.</p>
+
+<p>A post from one user after solving a problem with long delays:</p>
+<pre>Subject: Final Answer to Delay!!!
+   Date: Mon, 19 Feb 2001
+   From: "Felippe Solutions" &lt;felippe@solutionstecnologia.com.br&gt;
+
+Sorry people, but seems like the Delay problem had nothing to do with
+freeswan.
+
+The problem was DNS as some people sad from the beginning, but not the way
+they thought it was happening. Samba, ssh, telnet and other apps try to
+reverse lookup addresses when you use IP numbers (Stupid that ahh).
+
+I could ping very fast because I always ping with "-n" option, but I don't
+know the option on the other apps to stop reverse addressing so I don't use
+it.</pre>
+
+<p>This post is fairly typical. These problems are often tricky and
+frustrating to diagnose, and most turn out to be DNS-related.</p>
+
+<p>One suggestion for diagnosis: test with both names and addresses if
+possible. For example, try all of:</p>
+<ul>
+  <li>ping <var>address</var></li>
+  <li>ping -n <var>address</var></li>
+  <li>ping <var>name</var></li>
+</ul>
+
+<p>If these behave differently, the problem must be DNS-related since the
+three commands do exactly the same thing except for DNS lookups.</p>
+
+<h3><a name="route">I send packets to the tunnel with route(8) but they
+vanish</a></h3>
+
+<p>IPsec connections are designed to carry only packets travelling between
+pre-defined connection endpoints. As project technical lead Henry Spencer put
+it:</p>
+
+<blockquote>
+  IPsec tunnels are not just virtual wires; they are virtual wires with
+  built-in access controls.  Negotiation of an IPsec tunnel includes
+  negotiation of access rights for it, which don't include packets to/from
+  other IP addresses.  (The protocols themselves are quite inflexible about
+  this, so there are limits to what we can do about it.)</blockquote>
+
+<p>For fairly obvious security reasons, and to comply with the IPsec RFCs, <a
+href="glossary.html#KLIPS">KLIPS</a> drops any packets it receives that are
+not allowed on the tunnels currently defined. So if you send it packets with
+<var>route(8)</var>, and suitable tunnels are not defined, the packets
+vanish. Whether this is reported in the logs depends on the setting of
+<var>klipsdebug</var> in your <a
+href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a> file.</p>
+
+<p>To rescue vanishing packets, you must ensure that suitable tunnels for
+them exist, by editing the connection descriptions in <a
+href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a>. For example, supposing
+you have a simple setup:</p>
+<pre>         leftsubnet -- leftgateway === internet === roadwarrior</pre>
+
+<p>If you want to give the roadwarrior access to some resource that is
+located behind the left gateway but is not in the currently defined left
+subnet, then the usual procedure is to define an additional tunnel for those
+packets by creating a new connection description.</p>
+
+<p>In some cases, it may be easier to alter an existing connection
+description, enlarging the definition of <var>leftsubnet</var>. For example,
+instead of two connection descriptions with 192.168.8.0/24 and 192.168.9.0/24
+as their <var>leftsubnet</var> parameters, you can use a single description
+with 192.168.8.0/23.</p>
+
+<p>If you have multiple endpoints on each side, you need to ensure that there
+is a route for each pair of endpoints. See this <a
+href="adv_config.html#multitunnel">example</a>.</p>
+
+<h3><a name="down_route">When a tunnel goes down, packets vanish</a></h3>
+
+<p>This is a special case of the vanishing packet problem described in the
+previous question. Whenever KLIPS sees packets for which it does not have a
+tunnel, it drops them.</p>
+
+<p>When a tunnel goes away, either because negotiations with the other
+gateway failed or because you gave an <var>ipsec auto --down</var> command,
+the route to its other end is left pointing into KLIPS, and KLIPS will drop
+packets it has no tunnel for.</p>
+
+<p>This is a documented design decision, not a bug. FreeS/WAN must not
+automatically adjust things to send packets via another route. The other
+route might be insecure.</p>
+
+<p>Of course, re-routing may be necessary in many cases. In those cases, you
+have to do it manually or via scripts. We provide the <var>ipsec auto
+--unroute</var> command for these cases.</p>
+
+<p>From <a href="manpage.d/ipsec_auto.8.html">ipsec_auto(8)</a>:</p>
+
+<blockquote>
+  Normally,  pluto  establishes  a  route to the destination specified for a
+  connection as part of the --up  operation. However,  the  route and only
+  the route can be established with the --route operation.  Until and  unless
+  an  actual connection  is established, this discards any packets sent
+  there, which may be preferable to having them  sent elsewhere based  on  a
+  more  general  route (e.g., a default route).</blockquote>
+
+<blockquote>
+  Normally, pluto's route to a destination remains in  place when  a  --down
+  operation  is used to take the connection down (or if connection setup, or
+  later automatic rekeying, fails).   This permits establishing a new
+  connection (perhaps using a different specification; the route is altered
+  as necessary) without having a ``window'' in which packets might go
+  elsewhere based on a more general route.  Such  a route can be removed
+  using the --unroute operation (and is implicitly removed by
+--delete).</blockquote>
+
+<p>See also this mailing list <a
+href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/11/msg00523.html">message</a>.</p>
+
+<h3><a name="firewall_ate">The firewall ate my packets!</a></h3>
+
+<p>If firewalls filter out:</p>
+<ul>
+  <li>either the UDP port 500 packets used in IKE negotiations</li>
+  <li>or the ESP and AH (protocols 50 and 51) packets used to implement the
+    IPsec tunnel</li>
+</ul>
+
+<p>then IPsec cannot work. The first thing to check if packets seem to be
+vanishing is the firewall rules on the two gateway machines and any other
+machines along the path that you have access to.</p>
+
+<p>For details, see our document on <a href="firewall.html">firewalls</a>.</p>
+
+<p>Some advice from technical lead Henry Spencer on diagnosing such
+problems:</p>
+<pre>&gt; &gt; Packets vanishing between the hardware interface and the ipsecN interface
+&gt; &gt; is usually the result of firewalls not being configured to let them in...
+&gt; 
+&gt; Thanks for the suggestion. If only it were that simple! My ipchains startup
+&gt; script does take care of that, but just in case I manually inserted rules 
+&gt; accepting everything from london on dublin. No difference.
+
+The other thing to check is whether the "RX packets dropped" count on the
+ipsecN interface (run "ifconfig ipsecN", for N=1 or whatever, to see the
+counts) is rising.  If so, then there's some sort of configuration mismatch
+between the two ends, and IPsec itself is rejecting them.  If none of the
+ipsecN counts is rising, then the packets are never reaching the IPsec
+machinery, and the problem is almost certainly in firewalls etc.</pre>
+
+<h3><a name="dropconn">Dropped connections</a></h3>
+
+<p>Networks being what they are, IPsec connections can be broken for any
+number of reasons, ranging from hardware failures to various software
+problems such as the path MTU problems discussed <a
+href="#pmtu.broken">elsewhere in the FAQ</a>. Fortunately, various diagnostic
+tools exist that help you sort out many of the possible problems.</p>
+
+<p>There is one situation, however, where FreeS/WAN (using default settings)
+may destroy a connection for no readily apparent reason. This occurs when
+things are <strong>misconfigured</strong> so that <strong>two
+tunnels</strong> from the same gateway expect <strong>the same subnet on the
+far end</strong>.</p>
+
+<p>In this situation, the first tunnel comes up fine and works until the
+second is established. At that point, because of the way we track connections
+internally, the first tunnel ceases to exist as far as this gateway is
+concerned. Of course the far end does not know that, and a storm of error
+messages appears on both systems as it tries to use the tunnel.</p>
+
+<p>If the far end gives up, goes back to square one and negotiates a new
+tunnel, then that wipes out the second tunnel and ...</p>
+
+<p>The solution is simple. <strong>Do not build multiple conn descriptions
+with the same remote subnet</strong>.</p>
+
+<p>This is actually intended to be a feature, rather than a bug. Consider the
+situation where a single remote system goes down, then comes back up and
+reconnects to the gateway. It is useful to have the gateway tear down the old
+tunnel and recover resources when the reconnection is made. It recognises
+that situation by checking the remote subnet for each tunnel it builds and
+discarding duplicates. This works fine as long as you don't configure
+multiple tunnels with the same remote subnet.</p>
+
+<p>If this behaviour is inconvenient for you, you can disable it by setting
+<var>uniqueids=no</var> in <a
+href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a>.</p>
+
+
+<h3><a name="defaultroutegone">Disappearing %defaultroute</a></h3>
+
+<p>When an underlying connection (eg. ppp) goes down, FreeS/WAN will not 
+recover properly without a little help. Here are the symptoms that FreeS/WAN 
+user Michael Carmody noticed:
+<pre>
+&gt; After about 24 hours the freeswan connection takes over the default route.
+&gt; 
+&gt; i.e instead of deafult gateway pointing to the router via eth0, it becomes a 
+&gt; pointer to the router via ipsec0.
+ 
+&gt; All internet access is then lost as all replies (and not just the link I 
+&gt; wanted) are routed out ipsec0 and the router doesn't respond to the ipsec 
+&gt; traffic.
+</pre>
+
+<p>If you're using a  
+FreeS/WAN 2.x/KLIPS system, simply re-attach the IPsec virtual 
+interface with <em>ipsec tnconfig</em> command such as:</p>
+<pre>    ipsec tnconfig --attach --virtual ipsec0 --physical ppp0</pre>
+<p>In your command, name the physical and virtual interfaces as they 
+appear paired on your system during regular uptime. For a system with several
+physical/virtual interface pairs on flaky links, you'll need more than
+one such command.
+If you're using FreeS/WAN 1.x, you must restart FreeS/WAN, which is more time 
+consuming.</p>
+
+<p>
+<A href="http://lists.freeswan.org/pipermail/design/2002-July/003070.html">Here</A> 
+is a script which can help to automate the process of FreeS/WAN restart at 
+need. 
+It could easily be adapted to use tnconfig instead.</p>
+
+<h3><a name="tcpdump.faq">TCPdump on the gateway shows strange things</a></h3>
+
+As another user pointed out, keeping the connect
+<p>Attempting to look at IPsec packets by running monitoring tools on the
+IPsec gateway machine can produce silly results. That machine is mangling the
+packets for IPsec, and possibly for firewall or NAT purposes as well. If the
+internals of the machine's IP stack are not what the monitoring tool expects,
+then the tool can misinterpret them and produce nonsense output.</p>
+
+<p>See our <a href="testing.html#tcpdump.test">testing</a> document for more
+detail.</p>
+
+<h3><a name="no_trace">Traceroute does not show anything between the
+gateways</a></h3>
+
+<p>As far as traceroute can see, the two gateways are one hop apart; the data
+packet goes directly from one to the other through the tunnel. Of course the
+outer packets that implement the tunnel pass through whatever lies between
+the gateways, but those packets are built and dismantled by the gateways.
+Traceroute does not see them and cannot report anything about their path.</p>
+
+<p>Here is a mailing list message with more detail.</p>
+<pre>Date: Mon, 14 May 2001
+To: linux-ipsec@freeswan.org
+From: "John S. Denker" &lt;jsd@research.att.com&lt;
+Subject: Re: traceroute: one virtual hop
+
+At 02:20 PM 5/14/01 -0400, Claudia Schmeing wrote:
+&gt;
+&gt;&gt; &gt; A bonus question: traceroute in subnet to subnet enviroment looks like:
+&gt;&gt; &gt; 
+&gt;&gt; &gt; traceroute to andris.dmz (172.20.24.10), 30 hops max, 38 byte packets
+&gt;&gt; &gt; 1  drama (172.20.1.1)  0.716 ms  0.942 ms  0.434 ms
+&gt;&gt; &gt; 2  * * *
+&gt;&gt; &gt; 3  andris.dmz (172.20.24.10)  73.576 ms  78.858 ms  79.434 ms
+&gt;&gt; &gt; 
+&gt;&gt; &gt; Why aren't there the other hosts which take part in the delivery during 
+&gt;    * * * ?
+&gt;
+&gt;If there is an ipsec tunnel between GateA and Gate B, this tunnel forms a 
+&gt;'virtual wire'.  When it is tunneled, the original packet becomes an inner 
+&gt;packet, and new ESP and/or AH headers are added to create an outer packet 
+&gt;around it. You can see an example of how this is done for AH at 
+&gt;doc/ipsec.html#AH . For ESP it is similar.
+&gt;
+&gt;Think about the packet's path from the inner packet's perspective.
+&gt;It leaves the subnet, goes into the tunnel, and re-emerges in the second
+&gt;subnet. This perspective is also the only one available to the
+&gt;'traceroute' command when the IPSec tunnel is up.
+
+Claudia got this exactly right.  Let me just expand on a couple of points:
+
+*) GateB is exactly one (virtual) hop away from GateA.  This is how it
+would be if there were a physically private wire from A to B.  The
+virtually private connection should work the same, and it does.
+
+*) While the information is in transit from GateA to GateB, the hop count
+of the outer header (the "envelope") is being decremented.  The hop count
+of the inner header (the "contents" of the envelope) is not decremented and
+should not be decremented.  The hop count of the outer header is not
+derived from and should not be derived from the hop count of the inner header.
+
+Indeed, even if the packets did time out in transit along the tunnel, there
+would be no way for traceroute to find out what happened.  Just as
+information cannot leak _out_ of the tunnel to the outside, information
+cannot leak _into_ the tunnel from outside, and this includes ICMP messages
+from routers along the path.
+
+There are some cases where one might wish for information about what is
+happening at the IP layer (below the tunnel layer) -- but the protocol
+makes no provision for this.  This raises all sorts of conceptual issues.
+AFAIK nobody has ever cared enough to really figure out what _should_
+happen, let alone implement it and standardize it.
+
+*) I consider the "* * *" to be a slight bug.  One might wish for it to be
+replaced by "GateB GateB GateB".  It has to do with treating host-to-subnet
+traffic different from subnet-to-subnet traffic (and other gory details).
+I fervently hope KLIPS2 will make this problem go away.
+
+*) If you want to ask questions about the link from GateA to GateB at the
+IP level (below the tunnel level), you have to ssh to GateA and launch a
+traceroute from there.</pre>
+
+<h2><a name="man4debug">Testing in stages</a></h2>
+
+<p>It is often useful in debugging to test things one at a time:</p>
+<ul>
+  <li>disable IPsec entirely, for example by turning it off with
+    chkconfig(8), and make sure routing works</li>
+  <li>Once that works, try a manually keyed connection. This does not require
+    key negotiation between Pluto and the key daemon on the other end.</li>
+  <li>Once that works, try automatically keyed connections</li>
+  <li>Once IPsec works, add packet compression</li>
+  <li>Once everything seems to work, try stress tests with large transfers,
+    many connections, frequent re-keying, ...</li>
+</ul>
+
+<p>FreeS/WAN releases are tested for all of these, so you can be reasonably
+certain they <em>can</em> do them all. Of course, that does not mean they
+<em>will</em> on the first try, especially if you have some unusual
+configuration.</p>
+
+<p>The rest of this section gives information on diagnosing the problem when
+each of the above steps fails.</p>
+
+<h3><a name="nomanual">Manually keyed connections don't work</a></h3>
+
+<p>Suspect one of:</p>
+<ul>
+  <li>mis-configuration of IPsec system in the /etc/ipsec.conf file<br>
+    common errors are incorrect interface or next hop information</li>
+  <li>mis-configuration of manual connection in the /etc/ipsec.conf file</li>
+  <li>routing problems causing IPsec packets to be lost</li>
+  <li>bugs in KLIPS</li>
+  <li>mismatch between the transforms we support and those another IPsec
+    implementation offers.</li>
+</ul>
+
+<h3><a name="spi_error">One manual connection works, but second one
+fails</a></h3>
+
+<p>This is a fairly common problem when attempting to configure multiple
+manually keyed connections from a single gateway.</p>
+
+<p>Each connection must be identified by a unique <a
+href="glossary.html#SPI">SPI</a> value. For automatic connections, these
+values are assigned automatically. For manual connections, you must set them
+with <var>spi=</var> statements in <a
+href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a>.</p>
+
+<p>Each manual connection must have a unique SPI value in the range 0x100 to
+0x999. Two or more with the same value will fail. For details, see our doc
+section <a href="adv_config.html#prodman">Using manual keying in
+production</a> and the man page <a
+href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a>.</p>
+
+<h3><a name="man_no_auto">Manual connections work, but automatic keying
+doesn't</a></h3>
+
+<p>The most common reason for this behaviour is a firewall dropping the UDP
+port 500 packets used in key negotiation.</p>
+
+<p>Other possibilities:</p>
+<ul>
+  <li>mis-configuration of auto connection in the /etc/ipsec.conf file.
+    <p>One common configuration error is forgetting that you need
+    <var>auto=add</var> to load the connection description on the receiving
+    end so it recognises the connection when the other end asks for it.</p>
+  </li>
+  <li>error in shared secret in /etc/ipsec.secrets</li>
+  <li>one gateway lacks a route to the other so Pluto's UDP packets are
+  lost</li>
+  <li>bugs in Pluto</li>
+  <li>incompatibilities between Pluto's <a href="glossary.html#IKE">IKE</a>
+    implementation and the IKE at the other end of the tunnel.
+    <p>Some possibile problems are discussed in out <a
+    href="interop.html#interop.problem">interoperation</a> document.</p>
+  </li>
+</ul>
+
+<h3><a name="nocomp">IPsec works, but connections using compression
+fail</a></h3>
+
+<p>When we first added compression, we saw some problems:</p>
+<ul>
+  <li>compatibility issues with other implementations. We followed the RFCs
+    and omitted some extra material that many compression libraries add by
+    default. Some other implementations left the extras in</li>
+  <li>bugs in assembler compression routines on non-Intel CPUs. The
+    workaround is to use C code instead of possibly problematic
+  assembler.</li>
+</ul>
+
+<p>We have not seen either problem in some time (at least six months as I
+write in March 2002), but if you have some unusual configuration then you may
+see them.</p>
+
+<h3><a name="pmtu.broken">Small packets work, but large transfers
+fail</a></h3>
+
+<p>If tests with ping(1) and a small packet size succeed, but tests or
+transfers with larger packet sizes fail, suspect problems with packet
+fragmentation and perhaps <a href="glossary.html#pathMTU">path MTU
+discovery</a>.</p>
+
+<p>Our <a href="trouble.html#bigpacket">troubleshooting document</a> covers
+these problems. Information on the underlying mechanism is in our <a
+href="background.html#MTU.trouble">background</a> document.</p>
+
+<h3><a name="subsub">Subnet-to-subnet works, but tests from the gateways
+don't</a></h3>
+
+<p>This is described under <a href="#cantping">I cannot ping...</a> above.</p>
+
+<h2><a name="compile.faq">Compilation problems</a></h2>
+
+<h3><a name="gmp.h_missing">gmp.h: No such file or directory</a></h3>
+
+<p>Pluto needs the GMP (<strong>G</strong>NU</p>
+
+<p><strong>M</strong>ulti-<strong>P</strong>recision) library for the large
+integer calculations it uses in <a href="glossary.html#public">public key</a>
+cryptography. This error message indicates a failure to find the library. You
+must install it before Pluto will compile.</p>
+
+<p>The GMP library is included in most Linux distributions. Typically, there
+are two RPMs, libgmp and libgmp-devel, You need to <em>install both</em>,
+either from your distribution CDs or from your vendor's web site.</p>
+
+<p>On Debian, a mailing list message reports that the command to give is
+<var>apt-get install gmp2</var>.</p>
+
+<p>For more information and the latest version, see the <a
+href="http://www.swox.com/gmp/">GMP home page</a>.</p>
+
+<h3><a name="noVM">... virtual memory exhausted</a></h3>
+
+<p>We have had several reports of this message appearing, all on SPARC Linux.
+Here is a mailing message on a solution:</p>
+<pre>&gt; ipsec_sha1.c: In function `SHA1Transform':
+&gt; ipsec_sha1.c:95: virtual memory exhausted
+
+I'm seeing exactly the same problem on an Ultra with 256MB ram and 500
+MB swap.  Except I am compiling version 1.5 and its Red Hat 6.2.
+
+I can get around this by using -O instead of -O2 for the optimization
+level.  So it is probably a bug in the optimizer on the sparc complier. 
+I'll try and chase this down on the sparc lists.</pre>
+
+<h2><a name="error">Interpreting error messages</a></h2>
+
+<h3><a name="route-client">route-client (or host) exited with status
+7</a></h3>
+
+<p>Here is a discussion of this error from FreeS/WAN "listress" (mailing list
+tech support person) Claudia Schmeing. The "FAQ on the network unreachable
+error" which she refers to is the next question below.</p>
+<pre>&gt; I reached the point where the two boxes (both on dial-up connections, but
+&gt; treated as static IPs by getting the IP and editing ipsec.conf after the
+&gt; connection is established) to the point where they exchange some info, but I
+&gt; get an error like "route-client command exited with status 7 \n internal
+&gt; error".
+&gt; Where can I find a description of this error?
+
+In general, if the FAQ doesn't cover it, you can search the mailing list 
+archives - I like to use
+http://www.sandelman.ottawa.on.ca/linux-ipsec/
+but you can see doc/mail.html for different archive formats.
+
+
+Your error comes from the _updown script, which performs some
+routing and firewall functions to help Linux FreeS/WAN. More info
+is available at doc/firewall.html and man ipsec.conf. Its routing
+is integral to the health of Linux FreeS/WAN; it also provides facility
+to insert custom firewall rules to be executed when you create or destroy
+a connection.
+
+Yours is, of course, a routing error. You can be fairly sure the routing 
+machinery is saying "network is unreachable". There's a FAQ on the 
+"network is unreachable" error, but more information is available now; read on.
+
+If your _updown script is recent (for example if it shipped with 
+Linux FreeS/WAN 1.91), you will see another debugging line in your logs 
+that looks something like this:
+
+&gt; output: /usr/local/lib/ipsec/_updown: `route add -net 128.174.253.83 
+&gt; netmask 255.255.255.255 dev ipsec0 gw 66.92.93.161' failed
+
+This is, of course, the system route command that exited with status 7, 
+(ie. failed). Man route for details. Seeing the command typed out yields 
+more information. If your _updown script is older, you may wish to update 
+it to show the command explicitly.
+
+Three parameters fed to the route command: net, netmask and gw [gateway] 
+are derived from things you've put in ipsec.conf.
+
+Net and netmask are derived from the peer's IP and mask. In more detail:
+
+You may see a routing error when routing to a client (ie. subnet), or 
+to a host (IPSec gateway or freestanding host; a box that does IPSec for
+itself). In _updown, the "route-client" section  is responsible to set up 
+the route for IPSec'd (usually, read 'tunneled') packets headed to a 
+peer subnet. Similarly, route-host routes IPSec'd packets to a peer host
+or IPSec gateway.
+
+When routing to a 'client', net and netmask are ipsec.conf's left- or 
+rightsubnet (whichever is not local). Similarly, when routing to a 
+'host' the net is left or right. Host netmask is always /32, indicating a 
+single machine.
+
+Gw is nexthop's value. Again, the value in question is left- or rightnexthop,
+whichever is local. Where left/right or left-/rightnexthop has the special 
+value %defaultroute (described in man ipsec.conf), gw will automagically get
+the value of the next hop on the default route.
+
+Q: "What's a nexthop and why do I need one?"
+
+A: 'nexthop' is a routing kluge; its value is the next hop away
+   from the machine that's doing IPSec, and toward your IPSec peer. 
+   You need it to get the processed packets out of the local system and 
+   onto the wire. While we often route other packets through the machine 
+   that's now doing IPSec, and are done with it, this does not suffice here. 
+   After packets are processed with IPSec, this machine needs to know where 
+   they go next. Of course using the 'IPSec gateway' as their routing gateway 
+   would cause an infinite loop! [To visualize this, see the packet flow 
+   diagram at doc/firewall.html.] To avoid this, we route packets through 
+   the next hop down their projected path.
+
+Now that you know the background, consider:
+1. Did you test routing between the gateways in the absence of Linux
+   FreeS/WAN, as recommended? You need to ensure the two machines that
+   will be running Linux FreeS/WAN can route to one another before trying to 
+   make a secure connection.
+2. Is there anything obviously wrong with the sense of your route command?
+
+Normally, this problem is caused by an incorrect local nexthop parameter.
+Check out the use of %defaultroute, described in man ipsec.conf. This is
+a simple way to set nexthop for most people. To figure nexthop out by hand,
+traceroute in-the-clear to your IPSec peer. Nexthop is the traceroute's 
+first hop after your IPSec gateway.</pre>
+
+<h3><a name="unreachable">SIOCADDRT:Network is unreachable</a></h3>
+
+<p>This message is not from FreeS/WAN, but from the Linux IP stack itself.
+That stack is seeing packets it has no route for, either because your routing
+was broken before FreeS/WAN started or because FreeS/WAN's changes broke
+it.</p>
+
+<p>Here is a message from Claudia suggesting ways to diagnose and fix such
+problems:</p>
+<pre>You write,
+&gt; I have correctly installed freeswan-1.8 on RH7.0 kernel 2.2.17, but when 
+&gt; I setup a VPN connection with the other machine(RH5.2 Kernel 2.0.36 
+&gt; freeswan-1.0, it works well.) it told me that 
+&gt; "SIOCADDRT:Network is unreachable"!  But the network connection is no 
+&gt; problem.
+
+Often this error is the result of a misconfiguration. 
+
+Be sure that you can route successfully in the absence of Linux
+FreeS/WAN. (You say this is no problem, so proceed to the next step.)
+
+Use a custom copy of the default updownscript. Do not change the route 
+commands, but add a diagnostic message revealing the exact text of the 
+route command. Is there a problem with the sense of the route command
+that you can see? If so, then re-examine those ipsec.conf settings
+that are being sent to the route command. 
+
+You may wish to use the ipsec auto --route and --unroute commands to 
+troubleshoot the problem. See man ipsec_auto for details.</pre>
+
+<p>Since the above message was written, we have modified the updown script to
+provide a better diagnostic for this problem. Check
+<var>/var/log/messages</var>.</p>
+
+<p>See also the FAQ question <a href="#route-client">route-client (or host)
+exited with status 7</a>.</p>
+
+<h3><a name="modprobe">ipsec_setup: modprobe: Can't locate module
+ipsec</a></h3>
+
+<h3><a name="noKLIPS">ipsec_setup: Fatal error, kernel appears to lack
+KLIPS</a></h3>
+
+<p>These messages indicate an installation failure. The kernel you are
+running does not contain the <a href="glossary.html#KLIPS">KLIPS (kernel
+IPsec)</a> code.</p>
+
+<p>Note that the "modprobe: Can't locate module ipsec" message appears even
+if you are not using modules. If there is no KLIPS in your kernel, FreeS/WAN
+tries to load it as a module. If that fails, you get this message.</p>
+
+<p>Commands you can quickly try are:</p>
+<dl>
+  <dt><var>uname -a</var></dt>
+    <dd>to get details, including compilation date and time, of the currently
+      running kernel</dd>
+  <dt><var>ls /</var></dt>
+  <dt><var>ls /boot</var></dt>
+    <dd>to ensure a new kernel is where it should be. If kernel compilation
+      puts it in <var>/</var> but <var>lilo</var> wants it in
+      <var>/boot</var>, then you should uncomment the
+      <var>INSTALL_PATH=/boot</var> line in the kernel
+    <var>Makefile</var>.</dd>
+  <dt><var>more /etc/lilo.conf</var></dt>
+    <dd>to see that <var>lilo</var> has correct information</dd>
+  <dt><var>lilo</var></dt>
+    <dd>to ensure that information in <var>/etc/lilo.conf</var> has been
+      transferred to the boot sector</dd>
+</dl>
+
+<p>If those don't find the problem, you have to go back and check through the
+<a href="install.html">install</a> procedure to see what was missed.</p>
+
+<p>Here is one of Claudia's messages on the topic:</p>
+<pre>&gt; I tried to install freeswan 1.8 on my mandrake 7.2 test box. ...
+
+&gt; It does show version and some output for whack.
+
+Yes, because the Pluto (daemon) part of ipsec is installed correctly, but
+as we see below the kernel portion is not.
+
+&gt; However, I get the following from /var/log/messages:
+&gt; 
+&gt; Mar 11 22:11:55 pavillion ipsec_setup: Starting FreeS/WAN IPsec 1.8...
+&gt; Mar 11 22:12:02 pavillion ipsec_setup: modprobe: Can't locate module ipsec
+&gt; Mar 11 22:12:02 pavillion ipsec_setup: Fatal error, kernel appears to lack
+&gt; KLIPS.
+
+This is your problem. You have not successfully installed a kernel with
+IPSec machinery in it. 
+
+Did you build Linux FreeS/WAN as a module? If so, you need to ensure that 
+your new module has been installed in the directory where your kernel 
+loader normally finds your modules. If not, you need to ensure
+that the new IPSec-enabled kernel is being loaded correctly.
+
+See also doc/install.html, and INSTALL in the distro.</pre>
+
+<h3><a name="noDNS">ipsec_setup: ... failure to fetch key for ... from
+DNS</a></h3>
+
+<p>Quoting Henry:</p>
+<pre>Note that by default, FreeS/WAN is now set up to
+     (a) authenticate with RSA keys, and
+     (b) fetch the public key of the far end from DNS.
+Explicit attention to  ipsec.conf will be needed if you want
+to do something different.</pre>
+
+<p>and Claudia, responding to the same user:</p>
+<pre>You write,
+
+&gt;       My current setup in ipsec.conf is leftrsasigkey=%dns I have 
+&gt; commented this and authby=rsasig out. I am able to get ipsec running, 
+&gt; but what I find is that the documentation only specifies for %dns are 
+&gt; there any other values that can be placed in this variable other than 
+&gt; %dns and the key? I am also assuming that this is where I would place 
+&gt; my public key for the left and right side as well is this correct?
+
+Valid values for authby= are rsasig and secret, which entail authentication
+by RSA signature or by shared secret, respectively. Because you have 
+commented authby=rsasig out, you are using the default value of authby=secret. 
+
+When using RSA signatures, there are two ways to get the public key for the
+IPSec peer: either copy it directly into *rsasigkey= in ipsec.conf, or
+fetch it from dns. The magic value %dns for *rsasigkey parameters says to 
+try to fetch the peer's key from dns.
+
+For any parameters, you may find their significance and special values in
+man ipsec.conf. If you are setting up keys or secrets, be sure also to
+reference man ipsec.secrets.</pre>
+
+<h3><a name="dup_address">ipsec_setup: ... interfaces ... and ... share
+address ...</a></h3>
+
+<p>This is a fatal error. FreeS/WAN cannot cope with two or more interfaces
+using the same IP address. You must re-configure to avoid this.</p>
+
+<p>A mailing list message on the topic from Pluto developer Hugh
+Redelmeier:</p>
+<pre>| I'm trying to get freeswan working between two machine where one has a ppp
+| interface.
+| I've already suceeded with  two machines with ethernet ports but  the ppp
+| interface is causing me problems.
+|  basically when I run ipsec start  i get
+| ipsec_setup: Starting FreeS/WAN IPsec 1.7...
+| ipsec_setup: 003 IP interfaces ppp1 and ppp0 share address 192.168.0.10!
+| ipsec_setup: 003 IP interfaces ppp1 and ppp2 share address 192.168.0.10!
+| ipsec_setup: 003 IP interfaces ppp0 and ppp2 share address 192.168.0.10!
+| ipsec_setup: 003 no public interfaces found
+|
+| followed by lots of cannot work out interface for connection messages
+|
+| now I can specify the interface in ipsec.conf to be ppp0 , but this does
+| not affect the above behaviour. A quick look in server.c indicates that the
+| interfaces value  is not used but some sort of raw detect happens.
+|
+| I guess I could prevent the formation of the extra ppp interfaces or
+| allocate them different ip but I'd  rather not. if at all possible. Any
+| suggestions please.
+
+Pluto won't touch an interface that shares an IP address with another.
+This will eventually change, but it probably won't happen soon.
+
+For now, you will have to give the ppp1 and ppp2 different addresses.</pre>
+
+<h3><a name="kflags">ipsec_setup: Cannot adjust kernel flags</a></h3>
+
+<p>A mailing list message form technical lead Henry Spencer:</p>
+<pre>&gt; When FreeS/WAN IPsec 1.7 is starting on my 2.0.38 Linux kernel the following
+&gt; error message is generated:
+&gt; ipsec_setup: Cannot adjust kernel flags, no /proc/sys/net/ipsec directory!
+&gt; What is supposed to create this directory and how can I fix this problem?
+
+I think that directory is a 2.2ism, although I'm not certain (I don't have
+a 2.0.xx system handy any more for testing).  Without it, some of the
+ipsec.conf config-setup flags won't work, but otherwise things should
+function. </pre>
+
+<p>You also need to enable the <var>/proc</var> filesystem in your kernel
+configuration for these operations to work.</p>
+
+<h3><a name="message_num">Message numbers (MI3, QR1, et cetera) in Pluto
+messages</a></h3>
+
+<p>Pluto messages often indicate  where Pluto is in the IKE protocols. The
+letters indicate <strong>M</strong>ain mode or <strong>Q</strong>uick mode
+and <strong>I</strong>nitiator or <strong>R</strong>esponder. The numerals
+are message sequence numbers. For more detail, see our <a
+href="ipsec.html#sequence">IPsec section</a>.</p>
+
+<h3><a name="conn_name">Connection names in Pluto error messages</a></h3>
+
+<p>From Pluto programmer Hugh Redelmeier:</p>
+<pre>| Jan 17 16:21:10 remus Pluto[13631]: "jumble" #1: responding to Main Mode from Road Warrior 130.205.82.46
+| Jan 17 16:21:11 remus Pluto[13631]: "jumble" #1: no suitable connection for peer @banshee.wittsend.com
+| 
+|     The connection "jumble" has nothing to do with the incoming
+| connection requests, which were meant for the connection "banshee".
+
+You are right.  The message tells you which Connection Pluto is
+currently using, which need not be the right one.  It need not be the
+right one now for the negotiation to eventually succeed!  This is
+described in ipsec_pluto(8) in the section "Road Warrior Support".
+
+There are two times when Pluto will consider switching Connections for
+a state object.  Both are in response to receiving ID payloads (one in
+Phase 1 / Main Mode and one in Phase 2 / Quick Mode).  The second is
+not unique to Road Warriors.  In fact, neither is the first any more
+(two connections for the same pair of hosts could differ in Phase 1 ID
+payload; probably nobody else has tried this).</pre>
+
+<h3><a name="cantorient">Pluto: ... can't orient connection</a></h3>
+
+<p>Older versions of FreeS/WAN used this message. The same error now gives
+the "we have no ipsecN ..." error described just below.</p>
+
+<h3><a name="no.interface">... we have no ipsecN interface for either end of
+this connection</a></h3>
+
+<p>Your tunnel has no IP address which matches the IP
+address of any of the available IPsec interfaces. Either you've 
+misconfigured the connection, or you need to define an appropriate 
+IPsec interface connection. <VAR>interfaces=%defaultroute</VAR> works
+in many cases.</p>
+
+<p>A longer story: Pluto needs to know whether it is running on 
+the machine which the
+connection description calls <var>left</var> or on <var>right</var>. It
+figures that out by:</p>
+<ul>
+  <li>looking at the interfaces given in <var>interfaces=</var> lines in the
+    <var>config setup</var> section</li>
+  <li>discovering the IP addresses for those interfaces</li>
+  <li>searching for a match between those addresses and the ones given in
+    <var>left=</var> or <var>right=</var> lines.</li>
+</ul>
+
+<p>Normally a match is found. Then Pluto knows where it is and can set up
+other things (for example, if it is <var>left</var>) using parameters such as
+<var>leftsubnet</var> and <var>leftnexthop</var>, and sending its outgoing
+packets to <var>right</var>.</p>
+
+<p>If no match is found, it emits the above error message.</p>
+
+<h3><a name="noconn">Pluto: ... no connection is known</a></h3>
+
+<p>This error message occurs when a remote system attempts to negotiate a
+connection and Pluto does not have a connection description that matches what
+the remote system has requested. The most common cause is a configuration
+error on one end or the other.</p>
+
+<p>Parameters involved in this match are <var>left</var>, <var>right</var>,
+<var>leftsubnet</var> and <var>rightsubnet</var>.</p>
+
+<p><strong>The match must be exact</strong>. For example, if your left subnet
+is a.b.c.0/24 then neither a single machine in that net nor a smaller subnet
+such as a.b.c.64/26 will be considered a match.</p>
+
+<p>The message can also occur when an appropriate description exists but
+Pluto has not loaded it. Use an <var>auto=add</var> statement in the
+connection description, or an <var>ipsec auto --add &lt;conn_name&gt;</var>
+command, to correct this.</p>
+
+<p>An explanation from the Pluto developer:</p>
+<pre>| Jul 12 15:00:22 sohar58 Pluto[574]: "corp_road" #2: cannot respond to IPsec
+| SA request because no connection is known for
+| 216.112.83.112/32===216.112.83.112...216.67.25.118
+
+This is the first message from the Pluto log showing a problem.  It
+means that PGPnet is trying to negotiate a set of SAs with this
+topology:
+
+216.112.83.112/32===216.112.83.112...216.67.25.118
+^^^^^^^^^^^^^^^^^   ^^^^^^^^^^^^^^   ^^^^^^^^^^^^^
+client on our side  our host         PGPnet host, no client
+
+None of the conns you showed look like this.
+
+Use
+        ipsec auto --status
+to see a snapshot of what connections are in pluto, what
+negotiations are going on, and what SAs are established.
+
+The leftsubnet= (client) in your conn is 216.112.83.64/26.  It must
+exactly match what pluto is looking for, and it does not.</pre>
+
+<h3><a name="nosuit">Pluto: ... no suitable connection ...</a></h3>
+
+<p>This is similar to the <a href="#noconn">no connection known</a> error,
+but occurs at a different point in Pluto processing.</p>
+
+<p>Here is one of Claudia's messages explaining the problem:</p>
+<pre>You write,
+
+&gt; What could be the reason of the following error? 
+&gt; "no suitable connection for peer '@xforce'"
+
+When a connection is initiated by the peer, Pluto must choose which entry in 
+the conf file best matches the incoming connection. A preliminary choice is 
+made on the basis of source and destination IPs, since that information is 
+available at that time. 
+
+A payload containing an ID arrives later in the negotiation. Based on this
+id and the *id= parameters, Pluto refines its conn selection. ...
+
+The message "no suitable connection" indicates that in this refining step,
+Pluto does not find a connection that matches that ID.
+
+Please see "Selecting a connection when responding" in man ipsec_pluto for
+more details.</pre>
+
+<p>See also <a href="#conn_name">Connection names in Pluto error
+messages</a>.</p>
+
+<h3><a name="noconn.auth">Pluto: ... no connection has been
+authorized</a></h3>
+
+<p>Here is one of Claudia's messages discussing this problem:</p>
+<pre>You write,
+
+&gt;  May 22 10:46:31 debian Pluto[25834]: packet from x.y.z.p:10014: 
+&gt;  initial Main Mode message from x.y.z.p:10014 
+                            but no connection has been authorized
+
+This error occurs early in the connection negotiation process,
+at the first step of IKE negotiation (Main Mode), which is itself the 
+first of two negotiation phases involved in creating an IPSec connection.
+
+Here, Linux FreeS/WAN receives a packet from a potential peer, which 
+requests that they begin discussing a connection.
+
+The "no connection has been authorized" means that there is no connection 
+description in Linux FreeS/WAN's internal database that can be used to 
+link your ipsec interface with that peer.
+
+"But of course I configured that connection!" 
+
+It may be that the appropriate connection description exists in ipsec.conf 
+but has not been added to the database with ipsec auto --add myconn or the 
+auto=add method. Or, the connection description may be misconfigured.
+
+The only parameters that are relevant in this decision are left= and right= .
+Local and remote ports are also taken into account -- we see that the port 
+is printed in the message above -- but there is no way to control these
+in ipsec.conf.
+
+
+Failure at "no connection has been authorized" is similar to the
+"no connection is known for..." error in the FAQ, and the "no suitable
+connection" error described in the snapshot's FAQ. In all three cases,
+Linux FreeS/WAN is trying to match parameters received in the
+negotiation with the connection description in the local config file.
+
+As it receives more information, its matches take more parameters into 
+account, and become more precise:  first the pair of potential peers,
+then the peer IDs, then the endpoints (including any subnets).
+
+The "no suitable connection for peer *" occurs toward the end of IKE 
+(Main Mode) negotiation, when the IDs are matched.
+
+"no connection is known for a/b===c...d" is seen at the beginning of IPSec 
+(Quick Mode, phase 2) negotiation, when the connections are matched using
+left, right, and any information about the subnets.</pre>
+
+<h3><a name="noDESsupport">Pluto: ... OAKLEY_DES_CBC is not
+supported.</a></h3>
+
+<p>This message occurs when the other system attempts to negotiate a
+connection using <a href="glossary.html#DES">single DES</a>, which we do not
+support because it is <a href="politics.html#desnotsecure">insecure</a>.</p>
+
+<p>Our interoperation document has suggestions for <a
+href="interop.html#noDES">how to deal with</a> systems that attempt to use
+single DES.</p>
+
+<h3><a name="notransform">Pluto: ... no acceptable transform</a></h3>
+
+<p>This message means that the other gateway has made a proposal for
+connection parameters, but nothing they proposed is acceptable to Pluto.
+Possible causes include:</p>
+<ul>
+  <li>misconfiguration on either end</li>
+  <li>policy incompatibilities, for example we require encrypted connections
+    but they are trying to create one with just authentication</li>
+  <li>interoperation problems, for example they offer only single DES and
+    FreeS/WAN does not support that. See <a
+    href="interop.html#interop.problem">discussion</a> in our interoperation
+    document.</li>
+</ul>
+
+<p>A more detailed explanation, from Pluto programmer Hugh Redelmeier:</p>
+<pre>Background:
+
+When one IKE system (for example, Pluto) is negotiating with another
+to create an SA, the Initiator proposes a bunch of choices and the
+Responder replies with one that it has selected.
+
+The structure of the choices is fairly complicated.  An SA payload
+contains a list of lists of "Proposals".  The outer list is a set of
+choices: the selection must be from one element of this list.
+
+Each of these elements is a list of Proposals.  A selection must be
+made from each of the elements of the inner list.  In other words,
+*all* of them apply (that is how, for example, both AH and ESP can
+apply at once).
+
+Within each of these Proposals is a list of Transforms.  For each
+Proposal selected, one Transform must be selected (in other words,
+each Proposal provides a choice of Transforms).
+
+Each Transform is made up of a list of Attributes describing, well,
+attributes.  Such as lifetime of the SA.  Such as algorithm to be
+used.  All the Attributes apply to a Transform.
+
+You will have noticed a pattern here: layers alternate between being
+disjunctions ("or") and conjunctions ("and").
+
+For Phase 1 / Main Mode (negotiating an ISAKMP SA), this structure is
+cut back.  There must be exactly one Proposal.  So this degenerates to
+a list of Transforms, one of which must be chosen.
+
+In your case, no proposal was considered acceptable to Pluto (the
+Responder).  So negotiation ceased.  Pluto logs the reason it rejects
+each Transform.  So look back in the log to see what is going wrong.</pre>
+
+<h3><a name="rsasigkey">rsasigkey dumps core</a></h3>
+A comment on this error from Henry:
+<pre>On Fri, 29 Jun 2001, Rodrigo Gruppelli wrote:
+&gt; ...Well, it seem that there's
+&gt; another problem with it. When I try to generate a pair of RSA keys,
+&gt; rsasigkey cores dump...
+
+*That* is a neon sign flashing "GMP LIBRARY IS BROKEN".  Rsasigkey calls
+GMP a lot, and our own library a little bit, and that's very nearly all it
+does.  Barring bugs in its code or our library -- which have happened, but
+not very often -- a problem in rsasigkey is a problem in GMP.</pre>
+
+<p>See the next question for how to deal with GMP errors.</p>
+
+<h3><a name="sig4">!Pluto failure!: ... exited with ... signal 4</a></h3>
+
+<p>Pluto has died. Signal 4 is SIGILL, illegal instruction.</p>
+
+<p>The most likely cause is that your <a href="glossary.html#GMP">GMP</a>
+(GNU multi-precision) library is compiled for a different processor than what
+you are running on. Pluto uses that library for its public key
+calculations.</p>
+
+<p>Try getting the GMP sources and recompile for your processor type. Most
+Linux distributions will include this source, or you can download it from the
+<a href="http://www.swox.com/gmp/">GMP home page</a>.</p>
+
+<h3><a name="econnrefused">ECONNREFUSED error message</a></h3>
+
+<p>From John Denker, on the mailing list:</p>
+<pre>1)  The log message
+  some IKE message we sent has been rejected with 
+  ECONNREFUSED (kernel supplied no details)
+is much more suitable than the previous version.  Thanks.
+
+2) Minor suggestion for further improvement: it might be worth mentioning
+that the command
+  tcpdump -i eth1 icmp[0] != 8 and icmp[0] != 0
+is useful for tracking down the details in question.  We shouldn't expect
+all IPsec users to figure that out on their own.  The log message might
+even provide a hint as to where to look in the docs.</pre>
+
+<p>Reply From Pluto developer Hugh Redelmeier</p>
+<pre>Good idea.
+
+I've added a bit pluto(8)'s BUGS section along these lines.
+I didn't have the heart to lengthen this message.</pre>
+
+<h3><a name="no_eroute">klips_debug: ... no eroute!</a></h3>
+
+<p>This message means <a href="glossary.html#KLIPS">KLIPS</a> has received a
+packet for which no IPsec tunnel has been defined.</p>
+
+<p>Here is a more detailed duscussion from the team's tech support person
+Claudia Schmeing, responding to a query on the mailing list:</p>
+<pre>&gt; Why ipsec reports no eroute! ???? IP Masq... is disabled.
+
+In general, more information is required so that people on the list may
+give you informed input. See doc/prob.report.</pre>
+
+<p>The document she refers to has since been replaced by a <a
+href="trouble.html#prob.report">section</a> of the troubleshooting
+document.</p>
+<pre>However, I can make some general comments on this type of error.
+
+This error usually looks something like this (clipped from an archived
+message):
+
+&gt; ttl:64 proto:1 chk:45459 saddr:192.168.1.2 daddr:192.168.100.1
+&gt; ... klips_debug:ipsec_findroute: 192.168.1.2-&gt;192.168.100.1
+&gt; ... klips_debug:rj_match: * See if we match exactly as a host destination
+&gt; ... klips_debug:rj_match: ** try to match a leaf, t=0xc1a260b0
+&gt; ... klips_debug:rj_match: *** start searching up the tree, t=0xc1a260b0
+&gt; ... klips_debug:rj_match: **** t=0xc1a260c8
+&gt; ... klips_debug:rj_match: **** t=0xc1fe5960
+&gt; ... klips_debug:rj_match: ***** not found.
+&gt; ... klips_debug:ipsec_tunnel_start_xmit: Original head/tailroom: 2, 28
+&gt; ... klips_debug:ipsec_tunnel_start_xmit: no eroute!: ts=47.3030, dropping.
+
+
+What does this mean?
+- --------------------
+
+"eroute" stands for "extended route", and is a special type of route 
+internal to Linux FreeS/WAN. For more information about this type of route, 
+see the section of man ipsec_auto on ipsec auto --route.
+
+"no eroute!" here means, roughly, that Linux FreeS/WAN cannot find an 
+appropriate tunnel that should have delivered this packet. Linux 
+FreeS/WAN therefore drops the packet, with the message "no eroute! ...
+dropping", on the assumption that this packet is not a legitimate 
+transmission through a properly constructed tunnel.
+
+
+How does this situation come about?
+- -----------------------------------
+
+Linux FreeS/WAN has a number of connection descriptions defined in 
+ipsec.conf. These must be successfully brought "up" to form actual tunnels.
+(see doc/setup.html's step 15, man ipsec.conf and man ipsec_auto 
+for details).
+
+Such connections are often specific to the endpoints' IPs. However, in 
+some cases they may be more general, for example in the case of 
+Road Warriors where left or right is the special value %any.
+
+When Linux FreeS/WAN receives a packet, it verifies that the packet has
+come through a legitimate channel, by checking that there is an
+appropriate tunnel through which this packet might legitimately have
+arrived. This is the process we see above.
+
+First, it checks for an eroute that exactly matches the packet. In the 
+example above, we see it checking for a route that begins at 192.168.1.2
+and ends at 192.168.100.1. This search favours the most specific match that
+would apply to the route between these IPs. So, if there is a connection 
+description exactly matching these IPs, the search will end there. If not, 
+the code will search for a more general description matching the IPs.
+If there is no match, either specific or general, the packet will be
+dropped, as we see, above.
+
+Unless you are working with Road Warriors, only the first, specific part 
+of the matching process is likely to be relevant to you.
+
+
+"But I defined the tunnel, and it came up, why do I have this error?"
+- ---------------------------------------------------------------------
+
+One of the most common causes of this error is failure to specify enough
+connection descriptions to cover all needed tunnels between any two 
+gateways and their respective subnets. As you have noticed, troubleshooting
+this error may be complicated by the use of IP Masq. However, this error is
+not limited to cases where IP Masq is used. 
+
+See doc/configuration.html#multitunnel for a detailed example of the 
+solution to this type of problem.</pre>
+
+<p>The documentation section she refers to is now <a
+href="adv_config.html#multitunnel">here</a>.</p>
+
+<h3><a name="SAused">... trouble writing to /dev/ipsec ... SA already in
+use</a></h3>
+
+<p>This error message occurs when two manual connections are set up with the
+same SPI value. </p>
+
+<p>See the FAQ for <a href="#spi_error">One manual connection works, but
+second one fails</a>.</p>
+
+<h3><a name="ignore">... ignoring ... payload</a></h3>
+
+<p>This message is harmless. The IKE protocol provides for a number of
+optional messages types:</p>
+<ul>
+  <li>delete SA</li>
+  <li>initial contact</li>
+  <li>vendor ID</li>
+  <li>...</li>
+</ul>
+
+<p>An implementation is never required to send these, but they are allowed
+to. The receiver is not required to do anything with them. FreeS/WAN ignores
+them, but notifies you via the logs.</p>
+
+<p>For the "ignoring delete SA Payload" message, see also our discussion of
+cleaning up <a href="#deadtunnel">dead tunnels</a>.</p>
+
+<h3><a name="unknown_rightcert">unknown parameter name "rightcert"</a></h3>
+
+<P>This message can appear when you've upgraded an X.509-enabled 
+Linux FreeS/WAN with a vanilla Linux FreeS/WAN. To use your X.509 configs
+you will need to overwrite the new install with 
+<A HREF="http://www.freeswan.ca">Super FreeS/WAN</A>, or add the
+<A HREF="http://www.strongsec.ca/freeswan">X.509 patch</A> by hand.
+</P>
+
+<h2><a name="spam">Why don't you restrict the mailing lists to reduce
+spam?</a></h2>
+
+<p>As a matter of policy, some of our <a href="mail.html">mailing lists</a>
+need to be open to non-subscribers. Project management feel strongly that
+maintaining this openness is more important than blocking spam.</p>
+<ul>
+  <li>Users should be able to get help or report bugs without
+  subscribing.</li>
+  <li>Even a user who is subscribed may not have access to his or her
+    subscribed account when he or she needs help, miles from home base in the
+    middle of setting up a client's gateway.</li>
+  <li>There is arguably a legal requirement for this policy. A US resident or
+    citizen could be charged under munitions export laws for providing
+    technical assistance to a foreign cryptographic project. Such a charge
+    would be more easily defended if the discussion takes place in public, on
+    an open list.</li>
+</ul>
+
+<p>This has been discussed several times at some length on the list. See the
+<a href="mail.html#archive">list archives</a>. Bringing the topic up again is
+unlikely to be useful. Please don't. Or at the very least, please don't
+without reading the archives and being certain that whatever you are about to
+suggest has not yet been discussed.</p>
+
+<p>Project technical lead Henry Spencer summarised one discussion:</p>
+
+<blockquote>
+  For the third and last time:  this list *will* *not* do address-based
+  filtering.  This is a policy decision, not an implementation problem. The
+  decision is final, and is not open to discussion.  This needs to be
+  communicated better to people, and steps are being taken to do
+that.</blockquote>
+
+<p>Adding this FAQ section is one of the steps he refers to.</p>
+
+<p>You have various options other than just putting up with the spam,
+filtering it yourself, or unsubscribing:</p>
+<ul>
+  <li>subscribe only to one or both of our lists with restricted posting
+    rules:
+    <ul>
+      <li><a
+        href="mailto:briefs@lists.freeswan.org?body=subscribe">briefs</a>,
+        weekly list summaries</li>
+      <li><a
+        href="mailto:announce@lists.freeswan.org?body=subscribe">announce</a>,
+        project-related announcements</li>
+    </ul>
+  </li>
+  <li>read the other lists via the <a
+  href="mail.html#archive">archives</a></li>
+</ul>
+
+<p>A number of tools are available to filter mail.</p>
+<ul>
+  <li>Many mail readers include some filtering capability.</li>
+  <li>Many Linux distributions include <a
+    href="http://www.procmail.org/">procmail(8)</a> for server-side
+  filtering.</li>
+  <li>The <a href="http://www.spambouncer.org/">Spam Bouncer</a> is a set of
+    procmail(8) filters designed to combat spam.</li>
+  <li>Roaring Penguin have a <a
+    href="http://www.roaringpenguin.com/mimedefang/">MIME defanger</a> that
+    removes potentially dangerous attachments.</li>
+</ul>
+
+<p>If you use your ISP's mail server rather than running your own, consider
+suggesting to the ISP that they tag suspected spam as <a
+href="http://www.msen.com/1997/spam.html#SUSPECTED">this ISP</a> does. They
+could just refuse mail from dubious sources, but that is tricky and runs some
+risk of losing valuable mail or senselessly annoying senders and their
+admins. However, they can safely tag and deliver dubious mail. The tags can
+greatly assist your filtering.</p>
+
+<p>For information on tracking down spammers, see these <a
+href="http://www.rahul.net/falk/#howtos">HowTos</a>, or the <a
+href="http://www.sputum.com/index2.html">Sputum</a> site. Sputum have a Linux
+anti-spam screensaver available for download.</p>
+
+<p>Here is a more detailed message from Henry:</p>
+<pre>On Mon, 15 Jan 2001, Jay Vaughan wrote:
+&gt; I know I'm flogging a dead horse here, but I'm curious as to the reasons for
+&gt; an aversion for a subscriber-only mailing list?
+
+Once again:  for legal reasons, it is important that discussions of these
+things be held in a public place -- the list -- and we do not want to
+force people to subscribe to the list just to ask one question, because
+that may be more than merely inconvenient for them.  There are also real
+difficulties with people who are temporarily forced to use alternate
+addresses; that is precisely the time when they may be most in need of
+help, yet a subscribers-only policy shuts them out.
+
+These issues do not apply to most mailing lists, but for a list that is
+(necessarily) the primary user support route for a crypto package, they
+are very important.  This is *not* an ordinary mailing list; it has to
+function under awkward constraints that make various simplistic solutions
+inapplicable or undesirable. 
+
+&gt; We're *ALL* sick of hearing about list management problems, not just you
+&gt; old-timers, so why don't you DO SOMETHING EFFECTIVE ABOUT IT...
+
+Because it's a lot harder than it looks, and many existing "solutions"
+have problems when examined closely.
+
+&gt; A suggestion for you, based on 10 years of experience with management of my
+&gt; own mailing lists would be to use mailman, which includes pretty much every
+&gt; feature under the sun that you guys need and want, plus some.  The URL for
+&gt; mailman...
+
+I assure you, we're aware of mailman.  Along with a whole bunch of others,
+including some you almost certainly have never heard of (I hadn't!).
+
+&gt; As for the argument that the list shouldn't be configured to enforce
+&gt; subscription - I contend that it *SHOULD* AT LEAST require manual address
+&gt; verification in order for posts to be redirected.
+
+You do realize, I hope, that interposing such a manual step might cause
+your government to decide that this is not truly a public forum, and thus
+you could go to jail if you don't get approval from them before mailing to
+it?  If you think this sounds irrational, your government is noted for
+making irrational decisions in this area; we can't assume that they will
+suddenly start being sensible.  See above about awkward constraints.  You
+may be willing to take the risk, but we can't, in good conscience, insist
+that all users with problems do so. 
+
+                                                          Henry Spencer
+                                                       henry@spsystems.net</pre>
+
+<p>and a message on the topic from project leader John Gilmore:</p>
+<pre>Subject: Re: The linux-ipsec list's topic
+   Date: Sat, 30 Dec 2000
+   From: John Gilmore &lt;gnu@toad.com&gt;
+
+I'll post this single message, once only, in this discussion, and then
+not burden the list with any further off-topic messages.  I encourage
+everyone on the list to restrain themself from posting ANY off-topic
+messages to the linux-ipsec list.
+
+The topic of the linux-ipsec mailing list is the FreeS/WAN software.
+
+I frequently see "discussions about spam on a list" overwhelm the
+volume of "actual spam" on a list. BOTH kinds of messages are
+off-topic messages.  Twenty anti-spam messages take just as long to
+detect and discard as twenty spam messages.
+
+The Linux-ipsec list encourages on-topic messages from people who have
+not joined the list itself.  We will not censor messages to the list
+based on where they originate, or what return address they contain.
+In other words, non-subscribers ARE allowed to post, and this will not
+change.  My own valid contributions have been rejected out-of-hand by
+too many other mailing lists for me to want to impose that censorship
+on anybody else's contributions.  And every day I see the damage that
+anti-spam zeal is causing in many other ways; that zeal is far more
+damaging to the culture of the Internet than the nuisance of spam.
+
+In general, it is the responsibility of recipients to filter,
+prioritize, or otherwise manage the handling of email that comes to
+them.  It is not the responsibility of the rest of the Internet
+community to refrain from sending messages to recipients that they
+might not want to see.  If your software infrastructure for managing
+your incoming email is insufficient, then improve it.  If you think
+the signal-to-noise ratio on linux-ipsec is too poor, then please
+unsubscribe.  But don't further increase the noise by posting to the
+linux-ipsec list about those topics.
+
+        John Gilmore
+        founder &amp; sponsor, FreeS/WAN project</pre>
+</body>
+</html>
diff --git a/doc/src/firewall.html b/doc/src/firewall.html
new file mode 100644
index 000000000..5051b458d
--- /dev/null
+++ b/doc/src/firewall.html
@@ -0,0 +1,895 @@
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>FreeS/WAN and firewalls</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, FreeSWAN, firewall, ipchains, iptables">
+  <!--
+
+  Written by Sandy Harris for the Linux FreeS/WAN project
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: firewall.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+
+<body>
+<h1><a name="firewall">FreeS/WAN and firewalls</a></h1>
+
+<p>FreeS/WAN, or other IPsec implementations, frequently run on gateway
+machines, the same machines running firewall or packet filtering code. This
+document discusses the relation between the two.</p>
+
+<p>The firewall code in 2.4 and later kernels is called Netfilter. The
+user-space utility to manage a firewall is iptables(8). See the <a
+href="http://netfilter.samba.org">netfilter/iptables web site</a> for
+details.</p>
+
+<h2><a name="filters">Filtering rules for IPsec packets</a></h2>
+
+<p>The basic constraint is that <strong>an IPsec gateway must have packet
+filters that allow IPsec packets</strong>, at least when talking to other
+IPsec gateways:</p>
+<ul>
+  <li>UDP port 500 for <a href="glossary.html#IKE">IKE</a> negotiations</li>
+  <li>protocol 50 if you use <a href="glossary.html#ESP">ESP</a> encryption
+    and/or authentication (the typical case)</li>
+  <li>protocol 51 if you use <a href="glossary.html#AH">AH</a> packet-level
+    authentication</li>
+</ul>
+
+<p>Your gateway and the other IPsec gateways it communicates with must be
+able to exchange these packets for IPsec to work. Firewall rules must allow
+UDP 500 and at least one of <a href="glossary.html#AH">AH</a> or 
+<a href="glossary.html#ESP">ESP</a> on
+the interface that communicates with the other gateway.</p>
+
+<p>For nearly all FreeS/WAN applications, you must allow UDP port 500 and the
+ESP protocol.</p>
+
+<p>There are two ways to set this up:</p>
+<dl>
+  <dt>easier but less flexible</dt>
+    <dd>Just set up your firewall scripts at boot time to allow IPsec packets
+      to and from your gateway. Let FreeS/WAN reject any bogus packets.</dd>
+  <dt>more work, giving you more precise control</dt>
+    <dd>Have the <a href="manpage.d/ipsec_pluto.8.html">ipsec_pluto(8)</a>
+      daemon call scripts to adjust firewall rules dynamically as required.
+      This is done by naming the scripts in the <a
+      href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a> variables
+      <var>prepluto=</var>, <var>postpluto=</var>, <var>leftupdown=</var> and
+      <var>rightupdown=</var>.</dd>
+</dl>
+
+<p>Both methods are described in more detail below.</p>
+
+<h2><a name="examplefw">Firewall configuration at boot</a></h2>
+
+<p>It is possible to set up both firewalling and IPsec with appropriate
+scripts at boot and then not use <var>leftupdown=</var> and
+<var>rightupdown=</var>, or use them only for simple up and down
+operations.</p>
+
+<p>Basically, the technique is</p>
+<ul>
+  <li>allow IPsec packets (typically, IKE on UDP port 500 plus ESP, protocol
+    50)
+    <ul>
+      <li>incoming, if the destination address is your gateway (and
+        optionally, only from known senders)</li>
+      <li>outgoing, with the from address of your gateway (and optionally,
+        only to known receivers)</li>
+    </ul>
+  </li>
+  <li>let <a href="glossary.html#Pluto">Pluto</a> deal with IKE</li>
+  <li>let <a href="glossary.html#KLIPS">KLIPS</a> deal with ESP</li>
+</ul>
+
+<p>Since Pluto authenticates its partners during the negotiation, and KLIPS
+drops packets for which no tunnel has been negotiated, this may be all you
+need.</p>
+
+<h3><a name="simple.rules">A simple set of rules</a></h3>
+
+<p>In simple cases, you need only a few rules, as in this example:</p>
+<pre># allow IPsec
+#
+# IKE negotiations
+iptables -I INPUT  -p udp --sport 500 --dport 500 -j ACCEPT
+iptables -I OUTPUT -p udp --sport 500 --dport 500 -j ACCEPT
+# ESP encryption and authentication
+iptables -I INPUT  -p 50 -j ACCEPT
+iptables -I OUTPUT -p 50 -j ACCEPT
+</pre>
+
+<P>This should be all you need to allow IPsec through <var>lokkit</var>,
+which ships with Red Hat 9, on its medium security setting.
+Once you've tweaked to your satisfaction, save your active rule set with:</P>
+<PRE>service iptables save</PRE>
+
+<h3><a name="complex.rules">Other rules</a></h3>
+You can add additional rules, or modify existing ones, to work with IPsec and
+with your network and policies. We give a some examples in this section.
+
+<p>However, while it is certainly possible to create an elaborate set of
+rules yourself (please let us know via the <a href="mail.html">mailing
+list</a> if you do), it may be both easier and more secure to use a set which
+has already been published and tested.</p>
+
+<p>The published rule sets we know of are described in the <a
+href="#rules.pub">next section</a>.</p>
+
+<h4>Adding additional rules</h4>
+If necessary, you can add additional rules to:
+<dl>
+  <dt>reject IPsec packets that are not to or from known gateways</dt>
+    <dd>This possibility is discussed in more detail <a
+      href="#unknowngate">later</a></dd>
+  <dt>allow systems behind your gateway to build IPsec tunnels that pass
+  through the gateway</dt>
+    <dd>This possibility is discussed in more detail <a
+      href="#through">later</a></dd>
+  <dt>filter incoming packets emerging from KLIPS.</dt>
+    <dd>Firewall rules can recognise packets emerging from IPsec. They are
+      marked as arriving on an interface such as <var>ipsec0</var>, rather
+      than <var>eth0</var>, <var>ppp0</var> or whatever.</dd>
+</dl>
+
+<p>It is therefore reasonably straightforward to filter these packets in
+whatever way suits your situation.</p>
+
+<h4>Modifying existing rules</h4>
+
+<p>In some cases rules that work fine before you add IPsec may require
+modification to work with IPsec.</p>
+
+<p>This is especially likely for rules that deal with interfaces on the
+Internet side of your system. IPsec adds a new interface; often the rules
+must change to take account of that.</p>
+
+<p>For example, consider the rules given in <a
+href="http://www.netfilter.org/documentation/HOWTO//packet-filtering-HOWTO-5.html">this
+section</a> of the Netfilter documentation:</p>
+<pre>Most people just have a single PPP connection to the Internet, and don't
+want anyone coming back into their network, or the firewall:
+
+    ## Insert connection-tracking modules (not needed if built into kernel).
+    # insmod ip_conntrack
+    # insmod ip_conntrack_ftp
+
+    ## Create chain which blocks new connections, except if coming from inside.
+    # iptables -N block
+    # iptables -A block -m state --state ESTABLISHED,RELATED -j ACCEPT
+    # iptables -A block -m state --state NEW -i ! ppp0 -j ACCEPT
+    # iptables -A block -j DROP
+
+    ## Jump to that chain from INPUT and FORWARD chains.
+    # iptables -A INPUT -j block
+    # iptables -A FORWARD -j block</pre>
+
+<p>On an IPsec gateway, those rules may need to be modified. The above allows
+new connections from <em>anywhere except ppp0</em>. That means new
+connections from ipsec0 are allowed.</p>
+
+<p>Do you want to allow anyone who can establish an IPsec connection to your
+gateway to initiate TCP connections to any service on your network? Almost
+certainly not if you are using opportunistic encryption. Quite possibly not
+even if you have only explicitly configured connections.</p>
+
+<p>To disallow incoming connections from ipsec0, change the middle section
+above to:</p>
+<pre>    ## Create chain which blocks new connections, except if coming from inside.
+    # iptables -N block
+    # iptables -A block -m state --state ESTABLISHED,RELATED -j ACCEPT
+    # iptables -A block -m state --state NEW -i ppp+ -j DROP
+    # iptables -A block -m state --state NEW -i ipsec+ -j DROP
+    # iptables -A block -m state --state NEW -i -j ACCEPT
+    # iptables -A block -j DROP</pre>
+
+<p>The original rules accepted NEW connections from anywhere except ppp0.
+This version drops NEW connections from any PPP interface (ppp+) and from any
+ipsec interface (ipsec+), then accepts the survivors.</p>
+
+<p>Of course, these are only examples. You will need to adapt them to your
+own situation.</p>
+
+<h3><a name="rules.pub">Published rule sets</a></h3>
+
+<p>Several sets of firewall rules that work with FreeS/WAN are available.</p>
+
+<h4><a name="Ranch.trinity">Scripts based on Ranch's work</a></h4>
+
+<p>One user, Rob Hutton, posted his boot time scripts to the mailing list,
+and we included them in previous versions of this documentation. They are
+still available from our <a
+href="http://www.freeswan.org/freeswan_trees/freeswan-1.5/doc/firewall.html#examplefw">web
+site</a>. However, they were for an earlier FreeS/WAN version so we no longer
+recommend them. Also, they had some bugs. See this <a
+href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/04/msg00316.html">message</a>.</p>
+
+<p>Those scripts were based on David Ranch's scripts for his "Trinity OS" for
+setting up a secure Linux. Check his <a
+href="http://www.ecst.csuchico.edu/~dranch/LINUX/index-linux.html">home
+page</a> for the latest version and for information on his <a
+href="biblio.html#ranch">book</a> on securing Linux. If you are going to base
+your firewalling on Ranch's scripts, we recommend using his latest version,
+and sending him any IPsec modifications you make for incorporation into later
+versions.</p>
+
+<h4><a name="seawall">The Seattle firewall</a></h4>
+
+<p>We have had several mailing lists reports of good results using FreeS/WAN
+with Seawall (the Seattle Firewall). See that project's <a
+href="http://seawall.sourceforge.net/">home page</a> on Sourceforge.</p>
+
+<h4><a name="rcf">The RCF scripts</a></h4>
+
+<p>Another set of firewall scripts with IPsec support are the RCF or
+rc.firewall scripts. See their <a
+href="http://jsmoriss.mvlan.net/linux/rcf.html">home page</a>.</p>
+
+<h4><a name="asgard">Asgard scripts</a></h4>
+
+<p><a href="http://heimdall.asgardsrealm.net/linux/firewall/">Asgard's
+Realm</a> has set of firewall scripts with FreeS/WAN support, for 2.4 kernels
+and iptables.</p>
+
+<h4><a name="user.scripts">User scripts from the mailing list</a></h4>
+
+<p>One user gave considerable detail on his scripts, including supporting <a
+href="glossary.html#IPX">IPX</a> through the tunnel. His message was too long
+to conveniently be quoted here, so I've put it in a <a
+href="user_examples.html">separate file</a>.</p>
+
+<h2><a name="updown">Calling firewall scripts, named in ipsec.conf(5)</a></h2>
+
+<p>The <a href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a> configuration
+file has three pairs of parameters used to specify an interface between
+FreeS/WAN and firewalling code.</p>
+
+<p>Note that using these is not required if you have a static firewall setup.
+In that case, you just set your firewall up at boot time (in a way that
+permits the IPsec connections you want) and do not change it thereafter. Omit
+all the FreeS/WAN firewall parameters and FreeS/WAN will not attempt to
+adjust firewall rules at all. See <a href="#examplefw">above</a> for some
+information on appropriate scripts.</p>
+
+<p>However, if you want your firewall rules to change when IPsec connections
+change, then you need to use these parameters.</p>
+
+<h3><a name="pre_post">Scripts called at IPsec start and stop</a></h3>
+
+<p>One pair of parmeters are set in the <var>config setup</var> section of
+the <a href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a> file and affect
+all connections:</p>
+<dl>
+  <dt>prepluto=</dt>
+    <dd>script to be called before <a
+      href="manpage.d/ipsec_pluto.8.html">pluto(8)</a> IKE daemon is
+    started.</dd>
+  <dt>postpluto=</dt>
+    <dd>script to be called after <a
+      href="manpage.d/ipsec_pluto.8.html">pluto(8)</a> IKE daemon is
+    stopped.</dd>
+</dl>
+These parameters allow you to change firewall parameters whenever IPsec is
+started or stopped.
+
+<p>They can also be used in other ways. For example, you might have
+<var>prepluto</var> add a module to your kernel for the secure network
+interface or make a dialup connection, and then have <var>postpluto</var>
+remove the module or take the connection down.</p>
+
+<h3><a name="up_down">Scripts called at connection up and down</a></h3>
+
+<p>The other parameters are set in connection descriptions. They can be set
+in individual connection descriptions, and could even call different scripts
+for each connection for maximum flexibility. In most applications, however,
+it makes sense to use only one script and to call it from <var>conn
+%default</var> section so that it applies to all connections.</p>
+
+<p>You can:</p>
+<dl>
+  <dt><strong>either</strong></dt>
+    <dd>set <var>leftfirewall=yes</var> or <var>rightfirewall=yes</var> to
+      use our supplied default script</dd>
+  <dt><strong>or</strong></dt>
+    <dd>assign a name in a <var>leftupdown=</var> or <var>rightupdown=</var>
+      line to use your own script</dd>
+</dl>
+
+<p>Note that <strong>only one of these should be used</strong>. You cannot
+sensibly use both. Since <strong>our default script is obsolete</strong>
+(designed for firewalls using <var>ipfwadm(8)</var> on 2.0 kernels), most
+users who need this service will <strong>need to write a custom
+script</strong>.</p>
+
+<h4><a name="fw.default">The default script</a></h4>
+
+<p>We supply a default script named <var>_updown</var>.</p>
+<dl>
+  <dt>leftfirewall=</dt>
+    <dd></dd>
+  <dt>rightfirewall=</dt>
+    <dd>indicates that the gateway is doing firewalling and that <a
+      href="manpage.d/ipsec_pluto.8.html">pluto(8)</a> should poke holes in
+      the firewall as required.</dd>
+</dl>
+
+<p>Set these to <var>yes</var> and Pluto will call our default script
+<var>_updown</var> with appropriate arguments whenever it:</p>
+<ul>
+  <li>starts or stops IPsec services</li>
+  <li>brings a connection up or down</li>
+</ul>
+
+<p>The supplied default <var>_updown</var> script is appropriate for simple
+cases using the <var>ipfwadm(8)</var> firewalling package.</p>
+
+<h4><a name="userscript">User-written scripts</a></h4>
+
+<p>You can also write your own script and have Pluto call it. Just put the
+script's name in one of these <a
+href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a> lines:</p>
+<dl>
+  <dt>leftupdown=</dt>
+    <dd></dd>
+  <dt>rightupdown=</dt>
+    <dd>specifies a script to call instead of our default script
+      <var>_updown</var>.</dd>
+</dl>
+
+<p>Your script should take the same arguments and use the same environment
+variables as <var>_updown</var>. See the "updown command" section of the <a
+href="manpage.d/ipsec_pluto.8.html">ipsec_pluto(8)</a> man page for
+details.</p>
+
+<p>Note that <strong>you should not modify our _updown script in
+place</strong>. If you did that, then upgraded FreeS/WAN, the upgrade would
+install a new default script, overwriting your changes.</p>
+
+<h3><a name="ipchains.script">Scripts for ipchains or iptables</a></h3>
+
+<p>Our <var>_updown</var> is for firewalls using <var>ipfwadm(8)</var>, the
+firewall code for the 2.0 series of Linux kernels. If you are using the more
+recent packages <var>ipchains(8)</var> (for 2.2 kernels) or
+<var>iptables(8)</var> (2.4 kernels), then you must do one of:</p>
+<ul>
+  <li>use static firewall rules which are set up at boot time as described <a
+    href="#examplefw">above</a> and do not need to be changed by Pluto</li>
+  <li>limit yourself to ipchains(8)'s ipfwadm(8) emulation mode in order to
+    use our script</li>
+  <li>write your own script and call it with <var>leftupdown</var> and
+    <var>rightupdown</var>.</li>
+</ul>
+
+<p>You can write a script to do whatever you need with firewalling. Specify
+its name in a <var>[left|right]updown=</var> parameter in <a
+href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a> and Pluto will
+automatically call it for you.</p>
+
+<p>The arguments Pluto passes such a script are the same ones it passes to
+our default _updown script, so the best way to build yours is to copy ours
+and modify the copy.</p>
+
+<p>Note, however, that <strong>you should not modify our _updown script in
+place</strong>. If you did that, then upgraded FreeS/WAN, the upgrade would
+install a new default script, overwriting your changes.</p>
+
+<h2><a name="NAT">A complication: IPsec vs. NAT</a></h2>
+
+<p><a href="glossary.html#NAT.gloss">Network Address Translation</a>, also
+known as IP masquerading, is a method of allocating IP addresses dynamically,
+typically in circumstances where the total number of machines which need to
+access the Internet exceeds the supply of IP addresses.</p>
+
+<p>Any attempt to perform NAT operations on IPsec packets <em>between the
+IPsec gateways</em> creates a basic conflict:</p>
+<ul>
+  <li>IPsec wants to authenticate packets and ensure they are unaltered on a
+    gateway-to-gateway basis</li>
+  <li>NAT rewrites packet headers as they go by</li>
+  <li>IPsec authentication fails if packets are rewritten anywhere between
+    the IPsec gateways</li>
+</ul>
+
+<p>For <a href="glossary.html#AH">AH</a>, which authenticates parts of the
+packet header including source and destination IP addresses, this is fatal.
+If NAT changes those fields, AH authentication fails.</p>
+
+<p>For <a href="glossary.html#IKE">IKE</a> and <a
+href="glossary.html#ESP">ESP</a> it is not necessarily fatal, but is
+certainly an unwelcome complication.</p>
+
+<h3><a name="nat_ok">NAT on or behind the IPsec gateway works</a></h3>
+
+<p>This problem can be avoided by having the masquerading take place <em>on
+or behind</em> the IPsec gateway.</p>
+
+<p>This can be done physically with two machines, one physically behind the
+other. A picture, using SG to indicate IPsec <strong>S</strong>ecurity
+<strong>G</strong>ateways, is:</p>
+<pre>      clients --- NAT ----- SG ---------- SG
+                  two machines</pre>
+
+<p>In this configuration, the actual client addresses need not be given in
+the <var>leftsubnet=</var> parameter of the FreeS/WAN connection description.
+The security gateway just delivers packets to the NAT box; it needs only that
+machine's address. What that machine does with them does not affect
+FreeS/WAN.</p>
+
+<p>A more common setup has one machine performing both functions:</p>
+<pre>      clients ----- NAT/SG ---------------SG
+                  one machine</pre>
+
+<p>Here you have a choice of techniques depending on whether you want to make
+your client subnet visible to clients on the other end:</p>
+<ul>
+  <li>If you want the single gateway to behave like the two shown above, with
+    your clients hidden behind the NAT, then omit the <var>leftsubnet=</var>
+    parameter. It then defaults to the gateway address. Clients on the other
+    end then talk via the tunnel only to your gateway. The gateway takes
+    packets emerging from the tunnel, applies normal masquerading, and
+    forwards them to clients.</li>
+  <li>If you want to make your client machines visible, then give the client
+    subnet addresses as the <var>leftsubnet=</var> parameter in the
+    connection description and
+    <dl>
+      <dt>either</dt>
+        <dd>set <var>leftfirewall=yes</var> to use the default
+          <var>updown</var> script</dd>
+      <dt>or</dt>
+        <dd>use your own script by giving its name in a
+          <var>leftupdown=</var> parameter</dd>
+    </dl>
+    These scripts are described in their own <a href="#updown">section</a>.
+    <p>In this case, no masquerading is done. Packets to or from the client
+    subnet are encrypted or decrypted without any change to their client
+    subnet addresses, although of course the encapsulating packets use
+    gateway addresses in their headers. Clients behind the right security
+    gateway see a route via that gateway to the left subnet.</p>
+  </li>
+</ul>
+
+<h3><a name="nat_bad">NAT between gateways is problematic</a></h3>
+
+<p>We recommend not trying to build IPsec connections which pass through a
+NAT machine. This setup poses problems:</p>
+<pre>      clients --- SG --- NAT ---------- SG</pre>
+
+<p>If you must try it, some references are:</p>
+<ul>
+  <li>Jean_Francois Nadeau's document on doing <a
+    href="http://jixen.tripod.com/#NATed gateways">IPsec behind NAT</a></li>
+  <li><a href="web.html#VPN.masq">VPN masquerade patches</a> to make a Linux
+    NAT box handle IPsec packets correctly</li>
+</ul>
+
+<h3><a name="NAT.ref">Other references on NAT and IPsec</a></h3>
+
+<p>Other documents which may be relevant include:</p>
+<ul>
+  <li>an Internet Draft on <a
+    href="http://search.ietf.org/internet-drafts/draft-aboba-nat-ipsec-04.txt">IPsec
+    and NAT</a> which may eventually evolve into a standard solution for this
+    problem.</li>
+  <li>an informational <a
+    href="http://www.cis.ohio-state.edu/rfc/rfc2709.txt">RFC</a>,
+    <cite>Security Model with Tunnel-mode IPsec for NAT Domains</cite>.</li>
+  <li>an <a
+    href="http://www.cisco.com/warp/public/759/ipj_3-4/ipj_3-4_nat.html">article</a>
+    in Cisco's <cite>Internet Protocol Journal</cite></li>
+</ul>
+
+<h2><a name="complications">Other complications</a></h2>
+
+<p>Of course simply allowing UDP 500 and ESP packets is not the whole story.
+Various other issues arise in making IPsec and packet filters co-exist and
+even co-operate. Some of them are summarised below.</p>
+
+<h3><a name="through">IPsec <em>through</em></a> the gateway</h3>
+
+<p>Basic IPsec packet filtering rules deal only with packets addressed to or
+sent from your IPsec gateway.</p>
+
+<p>It is a separate policy decision whether to permit such packets to pass
+through the gateway so that client machines can build end-to-end IPsec
+tunnels of their own. This may not be practical if you are using <a
+href="#NAT">NAT (IP masquerade)</a> on your gateway, and may conflict with
+some corporate security policies.</p>
+
+<p>Where possible, allowing this is almost certainly a good idea. Using IPsec
+on an end-to-end basis is more secure than gateway-to-gateway.</p>
+
+<p>Doing it is quite simple. You just need firewall rules that allow UDP port
+500 and protocols 50 and 51 to pass through your gateway. If you wish, you
+can of course restrict this to certain hosts.</p>
+
+<h3><a name="ipsec_only">Preventing non-IPsec traffic</a></h3>
+You can also filter <em>everything but</em> UDP port 500 and ESP or AH to
+restrict traffic to IPsec only, either for anyone communicating with your
+host or just for specific partners.
+
+<p>One application of this is for the telecommuter who might have:</p>
+<pre>     Sunset==========West------------------East ================= firewall --- the Internet
+         home network      untrusted net        corporate network</pre>
+
+<p>The subnet on the right is 0.0.0.0/0, the whole Internet. The West gateway
+is set up so that it allows only IPsec packets to East in or out.</p>
+
+<p>This configuration is used in AT&amp;T Research's network. For details,
+see the <a href="intro.html#applied">papers</a> links in our introduction.</p>
+
+<p>Another application would be to set up firewall rules so that an internal
+machine, such as an employees-only web server, could not talk to the outside
+world except via specific IPsec tunnels.</p>
+
+<h3><a name="unknowngate">Filtering packets from unknown gateways</a></h3>
+
+<p>It is possible to use firewall rules to restrict UDP 500, ESP and AH
+packets so that these packets are accepted only from known gateways. This is
+not strictly necessary since FreeS/WAN will discard packets from unknown
+gateways. You might, however, want to do it for any of a number of reasons.
+For example:</p>
+<ul>
+  <li>Arguably, "belt and suspenders" is the sensible approach to security.
+    If you can block a potential attack in two ways, use both. The only
+    question is whether to look for a third way after implementing the first
+    two.</li>
+  <li>Some admins may prefer to use the firewall code this way because they
+    prefer firewall logging to FreeS/WAN's logging.</li>
+  <li>You may need it to implement your security policy. Consider an employee
+    working at home, and a policy that says traffic from the home system to
+    the Internet at large must go first via IPsec to the corporate LAN and
+    then out to the Internet via the corporate firewall. One way to do that
+    is to make <var>ipsec0</var> the default route on the home gateway and
+    provide exceptions only for UDP 500 and ESP to the corporate gateway.
+    Everything else is then routed via the tunnel to the corporate
+  gateway.</li>
+</ul>
+
+<p>It is not possible to use only static firewall rules for this filtering if
+you do not know the other gateways' IP addresses in advance, for example if
+you have "road warriors" who may connect from a different address each time
+or if want to do <a href="glossary.html#carpediem">opportunistic
+encryption</a> to arbitrary gateways. In these cases, you can accept UDP 500
+IKE packets from anywhere, then use the <a href="#updown">updown</a> script
+feature of <a href="manpage.d/ipsec_pluto.8.html">pluto(8)</a> to dynamically
+adjust firewalling for each negotiated tunnel.</p>
+
+<p>Firewall packet filtering does not much reduce the risk of a <a
+href="glossary.html#DOS">denial of service attack</a> on FreeS/WAN. The
+firewall can drop packets from unknown gateways, but KLIPS does that quite
+efficiently anyway, so you gain little. The firewall cannot drop otherwise
+legitmate packets that fail KLIPS authentication, so it cannot protect
+against an attack designed to exhaust resources by making FreeS/WAN perform
+many expensive authentication operations.</p>
+
+<p>In summary, firewall filtering of IPsec packets from unknown gateways is
+possible but not strictly necessary.</p>
+
+<h2><a name="otherfilter">Other packet filters</a></h2>
+
+<p>When the IPsec gateway is also acting as your firewall, other packet
+filtering rules will be in play. In general, those are outside the scope of
+this document. See our <a href="web.html#firewall.linux">Linux firewall
+links</a> for information. There are a few types of packet, however, which
+can affect the operation of FreeS/WAN or of diagnostic tools commonly used
+with it. These are discussed below.</p>
+
+<h3><a name="ICMP">ICMP filtering</a></h3>
+
+<p><a href="glossary.html#ICMP.gloss">ICMP</a> is the
+<strong>I</strong>nternet <strong>C</strong>ontrol <strong>M</strong>essage
+<strong>P</strong>rotocol. It is used for messages between IP implementations
+themselves, whereas IP used is used between the clients of those
+implementations. ICMP is, unsurprisingly, used for control messages. For
+example, it is used to notify a sender that a desination is not reachable, or
+to tell a router to reroute certain packets elsewhere.</p>
+
+<p>ICMP handling is tricky for firewalls.</p>
+<ul>
+  <li>You definitely want some ICMP messages to get through; things won't
+    work without them. For example, your clients need to know if some
+    destination they ask for is unreachable.</li>
+  <li>On the other hand, you do equally definitely do not want untrusted folk
+    sending arbitrary control messages to your machines. Imagine what someone
+    moderately clever and moderately malicious could do to you, given control
+    of your network's routing.</li>
+</ul>
+
+<p>ICMP does not use ports. Messages are distinguished by a "message type"
+field and, for some types, by an additional "code" field. The definitive list
+of types and codes is on the <a href="http://www.iana.org">IANA</a> site.</p>
+
+<p>One expert uses this definition for ICMP message types to be dropped at
+the firewall.</p>
+<pre># ICMP types which lack socially redeeming value.
+#  5     Redirect
+#  9     Router Advertisement
+# 10     Router Selection
+# 15     Information Request
+# 16     Information Reply
+# 17     Address Mask Request
+# 18     Address Mask Reply
+
+badicmp='5 9 10 15 16 17 18'</pre>
+
+<p>A more conservative approach would be to make a list of allowed types and
+drop everything else.</p>
+
+<p>Whichever way you do it, your ICMP filtering rules on a FreeS/WAN gateway
+should allow at least the following ICMP packet types:</p>
+<dl>
+  <dt>echo (type 8)</dt>
+    <dd></dd>
+  <dt>echo reply (type 0)</dt>
+    <dd>These are used by ping(1). We recommend allowing both types through
+      the tunnel and to or from your gateway's external interface, since
+      ping(1) is an essential testing tool.
+      <p>It is fairly common for firewalls to drop ICMP echo packets
+      addressed to machines behind the firewall. If that is your policy,
+      please create an exception for such packets arriving via an IPsec
+      tunnel, at least during intial testing of those tunnels.</p>
+    </dd>
+  <dt>destination unreachable (type 3)</dt>
+    <dd>This is used, with code 4 (Fragmentation Needed and Don't Fragment
+      was Set) in the code field, to control <a
+      href="glossary.html#pathMTU">path MTU discovery</a>. Since IPsec
+      processing adds headers, enlarges packets and may cause fragmentation,
+      an IPsec gateway should be able to send and receive these ICMP messages
+      <strong>on both inside and outside interfaces</strong>.</dd>
+</dl>
+
+<h3><a name="traceroute">UDP packets for traceroute</a></h3>
+
+<p>The traceroute(1) utility uses UDP port numbers from 33434 to
+approximately 33633. Generally, these should be allowed through for
+troubleshooting.</p>
+
+<p>Some firewalls drop these packets to prevent outsiders exploring the
+protected network with traceroute(1). If that is your policy, consider
+creating an exception for such packets arriving via an IPsec tunnel, at least
+during intial testing of those tunnels.</p>
+
+<h3><a name="l2tp">UDP for L2TP</a></h3>
+<p>
+Windows 2000 does, and products designed for compatibility with it may, build
+<a href="glossary.html#L2TP">L2TP</a> tunnels over IPsec connections.
+
+<p>For this to work, you must allow UDP protocol 1701 packets coming out of
+your tunnels to continue to their destination. You can, and probably should,
+block such packets to or from your external interfaces, but allow them from
+<var>ipsec0</var>.</p>
+
+<p>See also our Windows 2000 <a href="interop.html#win2k">interoperation
+discussion</a>.</p>
+
+<h2><a name="packets">How it all works: IPsec packet details</a></h2>
+
+<p>IPsec uses three main types of packet:</p>
+<dl>
+  <dt><a href="glossary.html#IKE">IKE</a> uses <strong>the UDP protocol and
+  port 500</strong>.</dt>
+    <dd>Unless you are using only (less secure, not recommended) manual
+      keying, you need IKE to negotiate connection parameters, acceptable
+      algorithms, key sizes and key setup. IKE handles everything required to
+      set up, rekey, repair or tear down IPsec connections.</dd>
+  <dt><a href="glossary.html#ESP">ESP</a> is <strong>protocol number
+  50</strong></dt>
+    <dd>This is required for encrypted connections.</dd>
+  <dt><a href="glossary.html#AH">AH</a> is <strong>protocol number
+  51</strong></dt>
+    <dd>This can be used where only authentication, not encryption, is
+      required.</dd>
+</dl>
+
+<p>All of those packets should have appropriate IPsec gateway addresses in
+both the to and from IP header fields. Firewall rules can check this if you
+wish, though it is not strictly necessary. This is discussed in more detail
+<a href="#unknowngate">later</a>.</p>
+
+<p>IPsec processing of incoming packets authenticates them then removes the
+ESP or AH header and decrypts if necessary. Successful processing exposes an
+inner packet which is then delivered back to the firewall machinery, marked
+as having arrived on an <var>ipsec[0-3]</var> interface. Firewall rules can
+use that interface label to distinguish these packets from unencrypted
+packets which are labelled with the physical interface they arrived on (or
+perhaps with a non-IPsec virtual interface such as <var>ppp0</var>).</p>
+
+<p>One of our users sent a mailing list message with a <a
+href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/12/msg00006.html">diagram</a>
+of the packet flow.</p>
+
+<h3><a name="noport">ESP and AH do not have ports</a></h3>
+
+<p>Some protocols, such as TCP and UDP, have the notion of ports. Others
+protocols, including ESP and AH, do not. Quite a few IPsec newcomers have
+become confused on this point. There are no ports <em>in</em> the ESP or AH
+protocols, and no ports used <em>for</em> them. For these protocols, <em>the
+idea of ports is completely irrelevant</em>.</p>
+
+<h3><a name="header">Header layout</a></h3>
+
+<p>The protocol numbers for ESP or AH are used in the 'next header' field of
+the IP header. On most non-IPsec packets, that field would have one of:</p>
+<ul>
+  <li>1 for ICMP</li>
+  <li>4 for IP-in-IP encapsulation</li>
+  <li>6 for TCP</li>
+  <li>17 for UDP</li>
+  <li>... or one of about 100 other possibilities listed by <a
+    href="http://www.iana.org">IANA</a></li>
+</ul>
+
+<p>Each header in the sequence tells what the next header will be. IPsec adds
+headers for ESP or AH near the beginning of the sequence. The original
+headers are kept and the 'next header' fields adjusted so that all headers
+can be correctly interpreted.</p>
+
+<p>For example, using <strong>[</strong> <strong>]</strong> to indicate data
+protected by ESP and unintelligible to an eavesdropper between the
+gateways:</p>
+<ul>
+  <li>a simple packet might have only IP and TCP headers with:
+    <ul>
+      <li>IP header says next header --&gt; TCP</li>
+      <li>TCP header port number --&gt; which process to send data to</li>
+      <li>data</li>
+    </ul>
+  </li>
+  <li>with ESP <a href="glossary.html#transport">transport mode</a>
+    encapsulation, that packet would have:
+    <ul>
+      <li>IP header says next header --&gt; ESP</li>
+      <li>ESP header <strong>[</strong> says next --&gt; TCP</li>
+      <li>TCP header port number --&gt; which process to send data to</li>
+      <li>data <strong>]</strong></li>
+    </ul>
+    Note that the IP header is outside ESP protection, visible to an
+    attacker, and that the final destination must be the gateway.</li>
+  <li>with ESP in <a href="glossary.html#tunnel">tunnel mode</a>, we might
+    have:
+    <ul>
+      <li>IP header says next header --&gt; ESP</li>
+      <li>ESP header <strong>[</strong> says next --&gt; IP</li>
+      <li>IP header says next header --&gt; TCP</li>
+      <li>TCP header port number --&gt; which process to send data to</li>
+      <li>data <strong>]</strong></li>
+    </ul>
+    Here the inner IP header is protected by ESP, unreadable by an attacker.
+    Also, the inner header can have a different IP address than the outer IP
+    header, so the decrypted packet can be routed from the IPsec gateway to a
+    final destination which may be another machine.</li>
+</ul>
+
+<p>Part of the ESP header itself is encrypted, which is why the
+<strong>[</strong> indicating protected data appears in the middle of some
+lines above. The next header field of the ESP header is protected. This makes
+<a href="glossary.html#traffic">traffic analysis</a> more difficult. The next
+header field would tell an eavesdropper whether your packet was UDP to the
+gateway, TCP to the gateway, or encapsulated IP. It is better not to give
+this information away. A clever attacker may deduce some of it from the
+pattern of packet sizes and timings, but we need not make it easy.</p>
+
+<p>IPsec allows various combinations of these to match local policies,
+including combinations that use both AH and ESP headers or that nest multiple
+copies of these headers.</p>
+
+<p>For example, suppose my employer has an IPsec VPN running between two
+offices so all packets travelling between the gateways for those offices are
+encrypted. If gateway policies allow it (The admins could block UDP 500 and
+protocols 50 and 51 to disallow it), I can build an IPsec tunnel from my
+desktop to a machine in some remote office. Those packets will have one ESP
+header throughout their life, for my end-to-end tunnel. For part of the
+route, however, they will also have another ESP layer for the corporate VPN's
+encapsulation. The whole header scheme for a packet on the Internet might
+be:</p>
+<ul>
+  <li>IP header (with gateway address) says next header --&gt; ESP</li>
+  <li>ESP header <strong>[</strong> says next --&gt; IP</li>
+  <li>IP header (with receiving machine address) says next header --&gt;
+  ESP</li>
+  <li>ESP header <strong>[</strong> says next --&gt; TCP</li>
+  <li>TCP header port number --&gt; which process to send data to</li>
+  <li>data <strong>]]</strong></li>
+</ul>
+
+<p>The first ESP (outermost) header is for the corporate VPN. The inner ESP
+header is for the secure machine-to-machine link.</p>
+
+<h3><a name="dhr">DHR on the updown script</a></h3>
+
+<p>Here are some mailing list comments from <a
+href="manpage.d/ipsec_pluto.8.html">pluto(8)</a> developer Hugh Redelmeier on
+an earlier draft of this document:</p>
+<pre>There are many important things left out
+
+- firewalling is important but must reflect (implement) policy.  Since
+  policy isn't the same for all our customers, and we're not experts,
+  we should concentrate on FW and MASQ interactions with FreeS/WAN.
+
+- we need a diagram to show packet flow WITHIN ONE MACHINE, assuming
+  IKE, IPsec, FW, and MASQ are all done on that machine.  The flow is
+  obvious if the components are run on different machines (trace the
+  cables).
+
+  IKE input:
+        + packet appears on public IF, as UDP port 500
+        + input firewalling rules are applied (may discard)
+        + Pluto sees the packet.
+
+  IKE output:
+        + Pluto generates the packet &amp; writes to public IF, UDP port 500
+        + output firewalling rules are applied (may discard)
+        + packet sent out public IF
+
+  IPsec input, with encapsulated packet, outer destination of this host:
+        + packet appears on public IF, protocol 50 or 51.  If this
+          packet is the result of decapsulation, it will appear
+          instead on the paired ipsec IF.
+        + input firewalling rules are applied (but packet is opaque)
+        + KLIPS decapsulates it, writes result to paired ipsec IF
+        + input firewalling rules are applied to resulting packet
+          as input on ipsec IF
+        + if the destination of the packet is this machine, the
+          packet is passed on to the appropriate protocol handler.
+          If the original packet was encapsulated more than once
+          and the new outer destination is this machine, that
+          handler will be KLIPS.
+        + otherwise:
+          * routing is done for the resulting packet.  This may well
+            direct it into KLIPS for encoding or encrypting.  What
+            happens then is described elsewhere.
+          * forwarding firewalling rules are applied
+          * output firewalling rules are applied
+          * the packet is sent where routing specified
+
+ IPsec input, with encapsulated packet, outer destination of another host:
+        + packet appears on some IF, protocol 50 or 51
+        + input firewalling rules are applied (but packet is opaque)
+        + routing selects where to send the packet
+        + forwarding firewalling rules are applied (but packet is opaque)
+        + packet forwarded, still encapsulated
+
+  IPsec output, from this host or from a client:
+        + if from a client, input firewalling rules are applied as the
+          packet arrives on the private IF
+        + routing directs the packet to an ipsec IF (this is how the
+          system decides KLIPS processing is required)
+        + if from a client, forwarding firewalling rules are applied
+        + KLIPS eroute mechanism matches the source and destination
+          to registered eroutes, yielding a SPI group.  This dictates
+          processing, and where the resulting packet is to be sent
+          (the destinations SG and the nexthop).
+        + output firewalling is not applied to the resulting
+          encapsulated packet
+
+- Until quite recently, KLIPS would double encapsulate packets that
+  didn't strictly need to be.  Firewalling should be prepared for
+  those packets showing up as ESP and AH protocol input packets on
+  an ipsec IF.
+
+- MASQ processing seems to be done as if it were part of the
+  forwarding firewall processing (this should be verified).
+
+- If a firewall is being used, it is likely the case that it needs to
+  be adjusted whenever IPsec SAs are added or removed.  Pluto invokes
+  a script to do this (and to adjust routing) at suitable times.  The
+  default script is only suitable for ipfwadm-managed firewalls.  Under
+  LINUX 2.2.x kernels, ipchains can be managed by ipfwadm (emulation),
+  but ipchains more powerful if manipulated using the ipchains command.
+  In this case, a custom updown script must be used.
+
+  We think that the flexibility of ipchains precludes us supplying an
+  updown script that would be widely appropriate.</pre>
+</body>
+</html>
diff --git a/doc/src/forwardingstate.txt b/doc/src/forwardingstate.txt
new file mode 100644
index 000000000..8853ac84e
--- /dev/null
+++ b/doc/src/forwardingstate.txt
@@ -0,0 +1,35 @@
+
+ 
+      .--------------. 	 
+      | non-existant |
+      |    policy    |
+      `--------------'
+             |        
+             | PF_ACQUIRE
+             |           
+             |<---------.
+             V          | new packet
+      .--------------.  | (maybe resend PF_ACQUIRE)
+      |  hold policy |--'                          
+      |              |--.                          
+      `--------------'   \  pass                   
+         |        |       \ msg    .---------.     
+         |        |        \       V         | forward
+         |        |         .-------------.  | packet 
+  create |        |         | pass policy |--'       
+  IPsec  |        |         `-------------'          
+  SA     |        |                                  
+         |         \                                 
+         |          \                                
+         V           \ 	deny                         
+   .---------.        \ msg                          
+   | encrypt |         \                             
+   | policy  |          \         ,---------.        
+   `---------'           \        |         | discard
+                          \       V         | packet 
+                           .-------------.  |        
+                           | deny policy |--'        
+                           '-------------'          
+                                                   
+    
+$Id: forwardingstate.txt,v 1.1 2004/03/15 20:35:24 as Exp $
diff --git a/doc/src/glossary.html b/doc/src/glossary.html
new file mode 100644
index 000000000..38d0db7bb
--- /dev/null
+++ b/doc/src/glossary.html
@@ -0,0 +1,2257 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>FreeS/WAN glossary</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, FreeSWAN, glossary, cryptography">
+  <!--
+
+  Written by Sandy Harris for the Linux FreeS/WAN project
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: glossary.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+
+<body>
+<h1><a name="ourgloss">Glossary for the Linux FreeS/WAN project</a></h1>
+
+<p>Entries are in alphabetical order. Some entries are only one line or one
+paragraph long. Others run to several paragraphs. I have tried to put the
+essential information in the first paragraph so you can skip the other
+paragraphs if that seems appropriate.</p>
+<hr>
+
+<h2><a name="jump">Jump to a letter in the glossary</a></h2>
+
+<center>
+<big><b><a href="#0">numeric</a> <a href="#A">A</a> <a href="#B">B</a> <a
+href="#C">C</a> <a href="#D">D</a> <a href="#E">E</a> <a href="#F">F</a> <a
+href="#G">G</a> <a href="#H">H</a> <a href="#I">I</a> <a href="#J">J</a> <a
+href="#K">K</a> <a href="#L">L</a> <a href="#M">M</a> <a href="#N">N</a> <a
+href="#O">O</a> <a href="#P">P</a> <a href="#Q">Q</a> <a href="#R">R</a> <a
+href="#S">S</a> <a href="#T">T</a> <a href="#U">U</a> <a href="#V">V</a> <a
+href="#W">W</a> <a href="#X">X</a> <a href="#Y">Y</a> <a
+href="#Z">Z</a></b></big></center>
+<hr>
+
+<h2><a name="gloss">Other glossaries</a></h2>
+
+<p>Other glossaries which overlap this one include:</p>
+<ul>
+  <li>The VPN Consortium's glossary of <a
+    href="http://www.vpnc.org/terms.html">VPN terms</a>.</li>
+  <li>glossary portion of the <a
+    href="http://www.rsa.com/rsalabs/faq/B.html">Cryptography FAQ</a></li>
+  <li>an extensive crytographic glossary on <a
+    href="http://www.ciphersbyritter.com/GLOSSARY.HTM">Terry Ritter's</a>
+    page.</li>
+  <li>The <a href="#NSA">NSA</a>'s <a
+    href="http://www.sans.org/newlook/resources/glossary.htm">glossary of
+    computer security</a> on the <a href="http://www.sans.org">SANS
+    Institute</a> site.</li>
+  <li>a small glossary for Internet Security at <a
+    href="http://www5.zdnet.com/pcmag/pctech/content/special/glossaries/internetsecurity.html">
+    PC magazine</a></li>
+  <li>The <a
+    href="http://www.visi.com/crypto/inet-crypto/glossary.html">glossary</a>
+    from Richard Smith's book <a href="#Smith">Internet Cryptography</a></li>
+</ul>
+
+<p>Several Internet glossaries are available as RFCs:</p>
+<ul>
+  <li><a href="http://www.rfc-editor.org/rfc/rfc1208.txt">Glossary of
+    Networking Terms</a></li>
+  <li><a href="http://www.rfc-editor.org/rfc/rfc1983.txt">Internet User's
+    Glossary</a></li>
+  <li><a href="http://www.rfc-editor.org/rfc/rfc2828.txt">Internet Security
+    Glossary</a></li>
+</ul>
+
+<p>More general glossary or dictionary information:</p>
+<ul>
+  <li>Free Online Dictionary of Computing (FOLDOC)
+    <ul>
+      <li><a href="http://www.nightflight.com/foldoc">North America</a></li>
+      <li><a
+      href="http://wombat.doc.ic.ac.uk/foldoc/index.html">Europe</a></li>
+      <li><a href="http://www.nue.org/foldoc/index.html">Japan</a></li>
+    </ul>
+    <p>There are many more mirrors of this dictionary.</p>
+  </li>
+  <li>The Jargon File, the definitive resource for hacker slang and folklore
+    <ul>
+      <li><a href="http://www.netmeg.net/jargon">North America</a></li>
+      <li><a href="http://info.wins.uva.nl/~mes/jargon/">Holland</a></li>
+      <li><a href="http://www.tuxedo.org/~esr/jargon">home page</a></li>
+    </ul>
+    <p>There are also many mirrors of this. See the home page for a list.</p>
+  </li>
+  <li>A general <a
+    href="http://www.trinity.edu/~rjensen/245glosf.htm#Navigate"> technology
+    glossary</a></li>
+  <li>An <a href="http://www.yourdictionary.com/">online dictionary resource
+    page</a> with pointers to many dictionaries for many languages</li>
+  <li>A <a href="http://www.onelook.com/">search engine</a> that accesses
+    several hundred online dictionaries</li>
+  <li>O'Reilly <a href="http://www.ora.com/reference/dictionary/">Dictionary
+    of PC Hardware and Data Communications Terms</a></li>
+  <li><a href="http://www.FreeSoft.org/CIE/index.htm">Connected</a> Internet
+    encyclopedia</li>
+  <li><a href="http://www.whatis.com/">whatis.com</a></li>
+</ul>
+<hr>
+
+<h2><a name="definitions">Definitions</a></h2>
+<dl>
+  <dt><a name="0">0</a></dt>
+  <dt><a name="3DES">3DES (Triple DES)</a></dt>
+    <dd>Using three <a href="#DES">DES</a> encryptions on a single data
+      block, with at least two different keys, to get higher security than is
+      available from a single DES pass. The three-key version of 3DES is the
+      default encryption algorithm for <a href="#FreeSWAN">Linux
+      FreeS/WAN</a>.
+      <p><a href="#IPSEC">IPsec</a> always does 3DES with three different
+      keys, as required by RFC 2451. For an explanation of the two-key
+      variant, see <a href="#2key">two key triple DES</a>. Both use an <a
+      href="#EDE">EDE</a> encrypt-decrypt-encrpyt sequence of operations.</p>
+      <p>Single <a href="#DES">DES</a> is <a
+      href="politics.html#desnotsecure">insecure</a>.</p>
+      <p>Double DES is ineffective. Using two 56-bit keys, one might expect
+      an attacker to have to do 2<sup>112</sup> work to break it. In fact,
+      only 2<sup>57</sup> work is required with a <a
+      href="#meet">meet-in-the-middle attack</a>, though a large amount of
+      memory is also required. Triple DES is vulnerable to a similar attack,
+      but that just reduces the work factor from the 2<sup>168</sup> one
+      might expect to 2<sup>112</sup>. That provides adequate protection
+      against <a href="#brute">brute force</a> attacks, and no better attack
+      is known.</p>
+      <p>3DES can be somewhat slow compared to other ciphers. It requires
+      three DES encryptions per block. DES was designed for hardware
+      implementation and includes some operations which are difficult in
+      software. However, the speed we get is quite acceptable for many uses.
+      See our <a href="performance.html">performance</a> document for
+      details.</p>
+    </dd>
+  <dt><a name="A">A</a></dt>
+  <dt><a name="active">Active attack</a></dt>
+    <dd>An attack in which the attacker does not merely eavesdrop (see <a
+      href="#passive">passive attack</a>) but takes action to change, delete,
+      reroute, add, forge or divert data. Perhaps the best-known active
+      attack is <a href="#middle">man-in-the-middle</a>. In general, <a
+      href="#authentication">authentication</a> is a useful defense against
+      active attacks.</dd>
+  <dt><a name="AES">AES</a></dt>
+    <dd>The <b>A</b>dvanced <b>E</b>ncryption <b>S</b>tandard -- a new <a
+      href="#block">block cipher</a> standard to replace <a
+      href="politics.html#desnotsecure">DES</a> -- developed by <a
+      href="#NIST">NIST</a>, the US National Institute of Standards and
+      Technology. DES used 64-bit blocks and a 56-bit key. AES ciphers use a
+      128-bit block and 128, 192 or 256-bit keys. The larger block size helps
+      resist <a href="#birthday">birthday attacks</a> while the large key
+      size prevents <a href="#brute">brute force attacks</a>.
+      <p>Fifteen proposals meeting NIST's basic criteria were submitted in
+      1998 and subjected to intense discussion and analysis, "round one"
+      evaluation. In August 1999, NIST narrowed the field to five "round two"
+      candidates:</p>
+      <ul>
+        <li><a href="http://www.research.ibm.com/security/mars.html">Mars</a>
+          from IBM</li>
+        <li><a href="http://www.rsa.com/rsalabs/aes/">RC6</a> from RSA</li>
+        <li><a
+          href="http://www.esat.kuleuven.ac.be/~rijmen/rijndael/">Rijndael</a>
+          from two Belgian researchers</li>
+        <li><a
+          href="http://www.cl.cam.ac.uk/~rja14/serpent.html">Serpent</a>, a
+          British-Norwegian-Israeli collaboration</li>
+        <li><a href="http://www.counterpane.com/twofish.html">Twofish</a>
+          from the consulting firm <a
+          href="http://www.counterpane.com">Counterpane</a></li>
+      </ul>
+      <p>Three of the five finalists -- Rijndael, Serpent and Twofish -- have
+      completely open licenses.</p>
+      <p>In October 2000, NIST announced the winner -- Rijndael.</p>
+      <p>For more information, see:</p>
+      <ul>
+        <li>NIST's <a
+          href="http://csrc.nist.gov/encryption/aes/aes_home.htm">AES home
+          page</a></li>
+        <li>the Block Cipher Lounge <a
+          href="http://www.ii.uib.no/~larsr/aes.html">AES page</a></li>
+        <li>Brian Gladman's <a
+          href="http://fp.gladman.plus.com/cryptography_technology/index.htm">code
+          and benchmarks</a></li>
+        <li>Helger Lipmaa's <a
+          href="http://www.tcs.hut.fi/~helger/aes/">survey of
+          implementations</a></li>
+      </ul>
+      <p>AES will be added to a future release of <a href="#FreeSWAN">Linux
+      FreeS/WAN</a>.  Likely we will add all three of the finalists with good
+      licenses. User-written <a href="web.html#patch">AES patches</a> are
+      already available.</p>
+      <p>Adding AES may also require adding stronger hashes, <a
+      href="#SHA-256">SHA-256, SHA-384 and SHA-512</a>.</p>
+    </dd>
+  <dt><a name="AH">AH</a></dt>
+    <dd>The <a href="#IPSEC">IPsec</a> <b>A</b>uthentication <b>H</b>eader,
+      added after the IP header. For details, see our <a
+      href="ipsec.html#AH.ipsec">IPsec</a> document and/or RFC 2402.</dd>
+  <dt><a name="alicebob">Alice and Bob</a></dt>
+    <dd>A and B, the standard example users in writing on cryptography and
+      coding theory. Carol and Dave join them for protocols which require
+      more players.
+      <p>Bruce Schneier extends these with many others such as Eve the
+      Eavesdropper and Victor the Verifier. His extensions seem to be in the
+      process of becoming standard as well. See page 23 of <a
+      href="biblio.html#schneier">Applied Cryptography</a></p>
+      <p>Alice and Bob have an amusing <a
+      href="http://www.conceptlabs.co.uk/alicebob.html"> biography</a> on the
+      web.</p>
+    </dd>
+  <dt>ARPA</dt>
+    <dd>see <a href="#DARPA">DARPA</a></dd>
+  <dt><a name="ASIO">ASIO</a></dt>
+    <dd>Australian Security Intelligence Organisation.</dd>
+  <dt>Asymmetric cryptography</dt>
+    <dd>See <a href="#public">public key cryptography</a>.</dd>
+  <dt><a name="authentication">Authentication</a></dt>
+    <dd>Ensuring that a message originated from the expected sender and has
+      not been altered on route. <a href="#IPSEC">IPsec</a> uses
+      authentication in two places:
+      <ul>
+        <li>peer authentication, authenticating the players in <a
+          href="#IKE">IKE</a>'s <a href="#DH">Diffie-Hellman</a> key
+          exchanges to prevent <a href="#middle">man-in-the-middle
+          attacks</a>. This can be done in a number of ways. The methods
+          supported by FreeS/WAN are discussed in our <a
+          href="adv_config.html#choose">advanced configuration</a>
+        document.</li>
+        <li>packet authentication, authenticating packets on an established
+          <a href="#SA">SA</a>, either with a separate <a
+          href="#AH">authentication header</a> or with the optional
+          authentication in the <a href="#ESP">ESP</a> protocol. In either
+          case, packet authentication uses a <a href="#HMAC">hashed message
+          athentication code</a> technique.</li>
+      </ul>
+      <p>Outside IPsec, passwords are perhaps the most common authentication
+      mechanism. Their function is essentially to authenticate the person's
+      identity to the system. Passwords are generally only as secure as the
+      network they travel over. If you send a cleartext password over a
+      tapped phone line or over a network with a packet sniffer on it, the
+      security provided by that password becomes zero. Sending an encrypted
+      password is no better; the attacker merely records it and reuses it at
+      his convenience. This is called a <a href="#replay">replay</a>
+      attack.</p>
+      <p>A common solution to this problem is a <a
+      href="#challenge">challenge-response</a> system. This defeats simple
+      eavesdropping and replay attacks. Of course an attacker might still try
+      to break the cryptographic algorithm used, or the <a
+      href="#random">random number</a> generator.</p>
+    </dd>
+  <dt><a name="auto">Automatic keying</a></dt>
+    <dd>A mode in which keys are automatically generated at connection
+      establisment and new keys automaically created periodically thereafter.
+      Contrast with <a href="#manual">manual keying</a> in which a single
+      stored key is used.
+      <p>IPsec uses the <a href="#DH">Diffie-Hellman key exchange
+      protocol</a> to create keys. An <a
+      href="#authentication">authentication</a> mechansim is required for
+      this. FreeS/WAN normally uses <a href="#RSA">RSA</a> for this. Other
+      methods supported are discussed in our <a
+      href="adv_config.html#choose">advanced configuration</a> document.</p>
+      <p>Having an attacker break the authentication is emphatically not a
+      good idea. An attacker that breaks authentication, and manages to
+      subvert some other network entities (DNS, routers or gateways), can use
+      a <a href="#middle">man-in-the middle attack</a> to break the security
+      of your IPsec connections.</p>
+      <p>However, having an attacker break the authentication in automatic
+      keying is not quite as bad as losing the key in manual keying.</p>
+      <ul>
+        <li>An attacker who reads /etc/ipsec.conf and gets the keys for a
+          manually keyed connection can, without further effort, read all
+          messages encrypted with those keys, including any old messages he
+          may have archived.</li>
+        <li>Automatic keying has a property called <a href="#PFS">perfect
+          forward secrecy</a>. An attacker who breaks the authentication gets
+          none of the automatically generated keys and cannot immediately
+          read any messages. He has to mount a successful <a
+          href="#middle">man-in-the-middle attack</a> in real time before he
+          can read anything. He cannot read old archived messages at all and
+          will not be able to read any future messages not caught by
+          man-in-the-middle tricks.</li>
+      </ul>
+      <p>That said, the secrets used for authentication, stored in <a
+      href="manpage.d/ipsec.secrets.5.html">ipsec.secrets(5)</a>, should
+      still be protected as tightly as cryptographic keys.</p>
+    </dd>
+  <dt><a name="B">B</a></dt>
+  <dt><a href="http://www.nortelnetworks.com">Bay Networks</a></dt>
+    <dd>A vendor of routers, hubs and related products, now a subsidiary of
+      Nortel. Interoperation between their IPsec products and Linux FreeS/WAN
+      was problematic at last report; see our <a
+      href="interop.html#bay">interoperation</a> section.</dd>
+  <dt><a name="benchmarks">benchmarks</a></dt>
+    <dd>Our default block cipher, <a href="#3DES">triple DES</a>, is slower
+      than many alternate ciphers that might be used. Speeds achieved,
+      however, seem adequate for many purposes. For example, the assembler
+      code from the <a href="#LIBDES">LIBDES</a> library we use encrypts 1.6
+      megabytes per second on a Pentium 200, according to the test program
+      supplied with the library.
+      <p>For more detail, see our document on <a
+      href="performance.html">FreeS/WAN performance</a>.</p>
+    </dd>
+  <dt><a name="BIND">BIND</a></dt>
+    <dd><b>B</b>erkeley <b>I</b>nternet <b>N</b>ame <b>D</b>aemon, a widely
+      used implementation of <a href="#DNS">DNS</a> (Domain Name Service).
+      See our bibliography for a <a href="#DNS">useful reference</a>. See the
+      <a href="http://www.isc.org/bind.html">BIND home page</a> for more
+      information and the latest version.</dd>
+  <dt><a name="birthday">Birthday attack</a></dt>
+    <dd>A cryptographic attack based on the mathematics exemplified by the <a
+      href="#paradox">birthday paradox</a>. This math turns up whenever the
+      question of two cryptographic operations producing the same result
+      becomes an issue:
+      <ul>
+        <li><a href="#collision">collisions</a> in <a href="#digest">message
+          digest</a> functions.</li>
+        <li>identical output blocks from a <a href="#block">block
+        cipher</a></li>
+        <li>repetition of a challenge in a <a
+          href="#challenge">challenge-response</a> system</li>
+      </ul>
+      <p>Resisting such attacks is part of the motivation for:</p>
+      <ul>
+        <li>hash algorithms such as <a href="#SHA">SHA</a> and <a
+          href="#RIPEMD">RIPEMD-160</a> giving a 160-bit result rather than
+          the 128 bits of <a href="#MD4">MD4</a>, <a href="#MD5">MD5</a> and
+          <a href="#RIPEMD">RIPEMD-128</a>.</li>
+        <li><a href="#AES">AES</a> block ciphers using a 128-bit block
+          instead of the 64-bit block of most current ciphers</li>
+        <li><a href="#IPSEC">IPsec</a> using a 32-bit counter for packets
+          sent on an <a href="#auto">automatically keyed</a> <a
+          href="#SA">SA</a> and requiring that the connection always be
+          rekeyed before the counter overflows.</li>
+      </ul>
+    </dd>
+  <dt><a name="paradox">Birthday paradox</a></dt>
+    <dd>Not really a paradox, just a rather counter-intuitive mathematical
+      fact. In a group of 23 people, the chance of a least one pair having
+      the same birthday is over 50%.
+      <p>The second person has 1 chance in 365 (ignoring leap years) of
+      matching the first. If they don't match, the third person's chances of
+      matching one of them are 2/365. The 4th, 3/365, and so on. The total of
+      these chances grows more quickly than one might guess.</p>
+    </dd>
+  <dt><a name="block">Block cipher</a></dt>
+    <dd>A <a href="#symmetric">symmetric cipher</a> which operates on
+      fixed-size blocks of plaintext, giving a block of ciphertext for each.
+      Contrast with <a href="#stream"> stream cipher</a>. Block ciphers can
+      be used in various <a href="#mode">modes</a> when multiple block are to
+      be encrypted.
+      <p><a href="#DES">DES</a> is among the the best known and widely used
+      block ciphers, but is now obsolete. Its 56-bit key size makes it <a
+      href="#desnotsecure">highly insecure</a> today. <a href="#3DES">Triple
+      DES</a> is the default block cipher for <a href="#FreeSWAN">Linux
+      FreeS/WAN</a>.</p>
+      <p>The current generation of block ciphers -- such as <a
+      href="#Blowfish">Blowfish</a>, <a href="#CAST128">CAST-128</a> and <a
+      href="#IDEA">IDEA</a> -- all use 64-bit blocks and 128-bit keys. The
+      next generation, <a href="#AES">AES</a>, uses 128-bit blocks and
+      supports key sizes up to 256 bits.</p>
+      <p>The <a href="http://www.ii.uib.no/~larsr/bc.html"> Block Cipher
+      Lounge</a> web site has more information.</p>
+    </dd>
+  <dt><a name="Blowfish">Blowfish</a></dt>
+    <dd>A <a href="#block">block cipher</a> using 64-bit blocks and keys of
+      up to 448 bits, designed by <a href="#schneier">Bruce Schneier</a> and
+      used in several products.
+      <p>This is not required by the <a href="#IPSEC">IPsec</a> RFCs and not
+      currently used in <a href="#FreeSWAN">Linux FreeS/WAN</a>.</p>
+    </dd>
+  <dt><a name="brute">Brute force attack (exhaustive search)</a></dt>
+    <dd>Breaking a cipher by trying all possible keys. This is always
+      possible in theory (except against a <a href="#OTP">one-time pad</a>),
+      but it becomes practical only if the key size is inadequate. For an
+      important example, see our document on the <a
+      href="#desnotsecure">insecurity of DES</a> with its 56-bit key. For an
+      analysis of key sizes required to resist plausible brute force attacks,
+      see <a href="http://www.counterpane.com/keylength.html">this paper</a>.
+      <p>Longer keys protect against brute force attacks. Each extra bit in
+      the key doubles the number of possible keys and therefore doubles the
+      work a brute force attack must do. A large enough key defeats
+      <strong>any</strong> brute force attack.</p>
+      <p>For example, the EFF's <a href="#EFF">DES Cracker</a> searches a
+      56-bit key space in an average of a few days. Let us assume an attacker
+      that can find a 64-bit key (256 times harder) by brute force search in
+      a second (a few hundred thousand times faster). For a 96-bit key, that
+      attacker needs 2<sup>32</sup> seconds, about 135 years. Against a
+      128-bit key, he needs 2<sup>32</sup> times that, over 500,000,000,000
+      years. Your data is then obviously secure against brute force attacks.
+      Even if our estimate of the attacker's speed is off by a factor of a
+      million, it still takes him over 500,000 years to crack a message.</p>
+      <p>This is why</p>
+      <ul>
+        <li>single <a href="#DES">DES</a> is now considered <a
+          href="#desnotsecure">dangerously insecure</a></li>
+        <li>all of the current generation of <a href="#block">block
+          ciphers</a> use a 128-bit or longer key</li>
+        <li><a href="#AES">AES</a> ciphers support keysizes 128, 192 and 256
+          bits</li>
+        <li>any cipher we add to Linux FreeS/WAN will have <em>at least</em>
+          a 128-bit key</li>
+      </ul>
+      <p><strong>Cautions:</strong><br>
+      <em>Inadequate keylength always indicates a weak cipher</em> but it is
+      important to note that <em>adequate keylength does not necessarily
+      indicate a strong cipher</em>. There are many attacks other than brute
+      force, and adequate keylength <em>only</em> guarantees resistance to
+      brute force. Any cipher, whatever its key size, will be weak if design
+      or implementation flaws allow other attacks.</p>
+      <p>Also, <em>once you have adequate keylength</em> (somewhere around 90
+      or 100 bits), <em>adding more key bits make no practical
+      difference</em>, even against brute force. Consider our 128-bit example
+      above that takes 500,000,000,000 years to break by brute force. We
+      really don't care how many zeroes there are on the end of that, as long
+      as the number remains ridiculously large. That is, we don't care
+      exactly how large the key is as long as it is large enough.</p>
+      <p>There may be reasons of convenience in the design of the cipher to
+      support larger keys. For example <a href="#Blowfish">Blowfish</a>
+      allows up to 448 bits and <a href="#RC4">RC4</a> up to 2048, but beyond
+      100-odd bits it makes no difference to practical security.</p>
+    </dd>
+  <dt>Bureau of Export Administration</dt>
+    <dd>see <a href="#BXA">BXA</a></dd>
+  <dt><a name="BXA">BXA</a></dt>
+    <dd>The US Commerce Department's <b>B</b>ureau of E<b>x</b>port
+      <b>A</b>dministration which administers the <a href="#EAR">EAR</a>
+      Export Administration Regulations controling the export of, among other
+      things, cryptography.</dd>
+  <dt><a name="C">C</a></dt>
+  <dt><a name="CA">CA</a></dt>
+    <dd><b>C</b>ertification <b>A</b>uthority, an entity in a <a
+      href="#PKI">public key infrastructure</a> that can certify keys by
+      signing them. Usually CAs form a hierarchy. The top of this hierarchy
+      is called the <a href="#rootCA">root CA</a>.
+      <p>See <a href="#web">Web of Trust</a> for an alternate model.</p>
+    </dd>
+  <dt><a name="CAST128">CAST-128</a></dt>
+    <dd>A <a href="#block">block cipher</a> using 64-bit blocks and 128-bit
+      keys, described in RFC 2144 and used in products such as <a
+      href="#Entrust">Entrust</a> and recent versions of <a
+      href="#PGP">PGP</a>.
+      <p>This is not required by the <a href="#IPSEC">IPsec</a> RFCs and not
+      currently used in <a href="#FreeSWAN">Linux FreeS/WAN</a>.</p>
+    </dd>
+  <dt>CAST-256</dt>
+    <dd><a href="#Entrust">Entrust</a>'s candidate cipher for the <a
+      href="#AES">AES standard</a>, largely based on the <a
+      href="#CAST128">CAST-128</a> design.</dd>
+  <dt><a name="CBC">CBC mode</a></dt>
+    <dd><b>C</b>ipher <b>B</b>lock <b>C</b>haining <a href="#mode">mode</a>,
+      a method of using a <a href="#block">block cipher</a> in which for each
+      block except the first, the result of the previous encryption is XORed
+      into the new block before it is encrypted. CBC is the mode used in <a
+      href="#IPSEC">IPsec</a>.
+      <p>An <a href="#IV">initialisation vector</a> (IV) must be provided. It
+      is XORed into the first block before encryption. The IV need not be
+      secret but should be different for each message and unpredictable.</p>
+    </dd>
+  <dt><a name="CIDR">CIDR</a></dt>
+    <dd><b>C</b>lassless <b>I</b>nter-<b>D</b>omain <b>R</b>outing,
+      an addressing scheme used to describe networks not
+      restricted to the old Class A, B, and C sizes.
+      A CIDR block is written
+      <VAR>address</VAR>/<VAR>mask</VAR>, where <VAR>address</VAR> is 
+      a 32-bit Internet address. 
+      The first <VAR>mask</VAR> bits of <VAR>address</VAR>
+      are part of the gateway address, while the remaining bits designate
+      other host addresses.
+      For example, the CIDR block 192.0.2.96/27 describes a network with 
+      gateway 
+      192.0.2.96, hosts 192.0.2.96 through 192.0.2.126 and broadcast 
+      192.0.2.127.
+      <p>FreeS/WAN policy group files accept CIDR blocks of the format
+      <VAR>address</VAR>/[<VAR>mask</VAR>], where <VAR>address</VAR> may
+      take the form <VAR>name.domain.tld</VAR>. An absent <VAR>mask</VAR>
+      is assumed to be /32.
+      </p> 
+    </dd>
+
+  <dt>Certification Authority</dt>
+    <dd>see <a href="#CA">CA</a></dd>
+  <dt><a name="challenge">Challenge-response authentication</a></dt>
+    <dd>An <a href="#authentication">authentication</a> system in which one
+      player generates a <a href="#random">random number</a>, encrypts it and
+      sends the result as a challenge. The other player decrypts and sends
+      back the result. If the result is correct, that proves to the first
+      player that the second player knew the appropriate secret, required for
+      the decryption. Variations on this technique exist using <a
+      href="#public">public key</a> or <a href="#symmetric">symmetric</a>
+      cryptography. Some provide two-way authentication, assuring each player
+      of the other's identity.
+      <p>This is more secure than passwords against two simple attacks:</p>
+      <ul>
+        <li>If cleartext passwords are sent across the wire (e.g. for
+          telnet), an eavesdropper can grab them. The attacker may even be
+          able to break into other systems if the user has chosen the same
+          password for them.</li>
+        <li>If an encrypted password is sent, an attacker can record the
+          encrypted form and use it later. This is called a replay
+        attack.</li>
+      </ul>
+      <p>A challenge-response system never sends a password, either cleartext
+      or encrypted.  An attacker cannot record the response to one challenge
+      and use it as a response to a later challenge. The random number is
+      different each time.</p>
+      <p>Of course an attacker might still try to break the cryptographic
+      algorithm used, or the <a href="#random">random number</a>
+      generator.</p>
+    </dd>
+  <dt><a name="mode">Cipher Modes</a></dt>
+    <dd>Different ways of using a block cipher when encrypting multiple
+      blocks.
+      <p>Four standard modes were defined for <a href="#DES">DES</a> in <a
+      href="#FIPS">FIPS</a> 81. They can actually be applied with any block
+      cipher.</p>
+
+      <table>
+        <tbody>
+          <tr>
+            <td></td>
+            <td><a href="#ECB">ECB</a></td>
+            <td>Electronic CodeBook</td>
+            <td>encrypt each block independently</td>
+          </tr>
+          <tr>
+            <td></td>
+            <td><a href="#CBC">CBC</a></td>
+            <td>Cipher Block Chaining<br>
+            </td>
+            <td>XOR previous block ciphertext into new block plaintext before
+              encrypting new block</td>
+          </tr>
+          <tr>
+            <td></td>
+            <td>CFB</td>
+            <td>Cipher FeedBack</td>
+            <td></td>
+          </tr>
+          <tr>
+            <td></td>
+            <td>OFB</td>
+            <td>Output FeedBack</td>
+            <td></td>
+          </tr>
+        </tbody>
+      </table>
+      <p><a href="#IPSEC">IPsec</a> uses <a href="#CBC">CBC</a> mode since
+      this is only marginally slower than <a href="#ECB">ECB</a> and is more
+      secure. In ECB mode the same plaintext always encrypts to the same
+      ciphertext, unless the key is changed. In CBC mode, this does not
+      occur.</p>
+      <p>Various other modes are also possible, but none of them are used in
+      IPsec.</p>
+    </dd>
+  <dt><a name="ciphertext">Ciphertext</a></dt>
+    <dd>The encrypted output of a cipher, as opposed to the unencrypted <a
+      href="#plaintext">plaintext</a> input.</dd>
+  <dt><a href="http://www.cisco.com">Cisco</a></dt>
+    <dd>A vendor of routers, hubs and related products. Their IPsec products
+      interoperate with Linux FreeS/WAN; see our <a
+      href="interop.html#Cisco">interop</a> section.</dd>
+  <dt><a name="client">Client</a></dt>
+    <dd>This term has at least two distinct uses in discussing IPsec:
+      <ul>
+        <li>The <strong>clients of an IPsec gateway</strong> are the machines
+          it protects, typically on one or more subnets behind the gateway.
+          In this usage, all the machines on an office network are clients of
+          that office's IPsec gateway. Laptop or home machines connecting to
+          the office, however, are <em>not</em> clients of that gateway. They
+          are remote gateways, running the other end of an IPsec connection.
+          Each of them is also its own client.</li>
+        <li><strong>IPsec client software</strong> is used to describe
+          software which runs on various standalone machines to let them
+          connect to IPsec networks. In this usage, a laptop or home machine
+          connecting to the office is a client, and the office gateway is the
+          server.</li>
+      </ul>
+      <p>We generally use the term in the first sense. Vendors of Windows
+      IPsec solutions often use it in the second. See this <a
+      href="interop.html#client.server">discussion</a>.</p>
+    </dd>
+  <dt><a name="cc">Common Criteria</a></dt>
+    <dd>A set of international security classifications which are replacing
+      the old US <a href="#rainbow">Rainbow Book</a> standards and similar
+      standards in other countries.
+      <p>Web references include this <a href="http://csrc.nist.gov/cc">US
+      government site</a> and this <a
+      href="http://www.commoncriteria.org">global home page</a>.</p>
+    </dd>
+  <dt>Conventional cryptography</dt>
+    <dd>See <a href="#symmetric">symmetric cryptography</a></dd>
+  <dt><a name="collision">Collision resistance</a></dt>
+    <dd>The property of a <a href="#digest">message digest</a> algorithm
+      which makes it hard for an attacker to find or construct two inputs
+      which hash to the same output.</dd>
+  <dt>Copyleft</dt>
+    <dd>see GNU <a href="#GPL">General Public License</a></dd>
+  <dt><a name="CSE">CSE</a></dt>
+    <dd><a href="http://www.cse-cst.gc.ca/">Communications Security
+      Establishment</a>, the Canadian organisation for <a
+      href="#SIGINT">signals intelligence</a>.</dd>
+  <dt><a name="D">D</a></dt>
+  <dt><a name="DARPA">DARPA (sometimes just ARPA)</a></dt>
+    <dd>The US government's <b>D</b>efense <b>A</b>dvanced <b>R</b>esearch
+      <b>P</b>rojects <b>A</b>gency. Projects they have funded over the years
+      have included the Arpanet which evolved into the Internet, the TCP/IP
+      protocol suite (as a replacement for the original Arpanet suite), the
+      Berkeley 4.x BSD Unix projects, and <a href="#SDNS">Secure DNS</a>.
+      <p>For current information, see their <a
+      href="http://www.darpa.mil/ito">web site</a>.</p>
+    </dd>
+  <dt><a name="DOS">Denial of service (DoS) attack</a></dt>
+    <dd>An attack that aims at denying some service to legitimate users of a
+      system, rather than providing a service to the attacker.
+      <ul>
+        <li>One variant is a flooding attack, overwhelming the system with
+          too many packets, to much email, or whatever.</li>
+        <li>A closely related variant is a resource exhaustion attack. For
+          example, consider a "TCP SYN flood" attack. Setting up a TCP
+          connection involves a three-packet exchange:
+          <ul>
+            <li>Initiator: Connection please (SYN)</li>
+            <li>Responder: OK (ACK)</li>
+            <li>Initiator: OK here too</li>
+          </ul>
+          <p>If the attacker puts bogus source information in the first
+          packet, such that the second is never delivered, the responder may
+          wait a long time for the third to come back. If responder has
+          already allocated memory for the connection data structures, and if
+          many of these bogus packets arrive, the responder may run out of
+          memory.</p>
+        </li>
+        <li>Another variant is to feed the system undigestible data, hoping
+          to make it sick. For example, IP packets are limited in size to 64K
+          bytes and a fragment carries information on where it starts within
+          that 64K and how long it is. The "ping of death" delivers fragments
+          that say, for example, that they start at 60K and are 20K long.
+          Attempting to re-assemble these without checking for overflow can
+          be fatal.</li>
+      </ul>
+      <p>The two example attacks discussed were both quite effective when
+      first discovered, capable of crashing or disabling many operating
+      systems. They were also well-publicised, and today far fewer systems
+      are vulnerable to them.</p>
+    </dd>
+  <dt><a name="DES">DES</a></dt>
+    <dd>The <b>D</b>ata <b>E</b>ncryption <b>S</b>tandard, a <a
+      href="#block">block cipher</a> with 64-bit blocks and a 56-bit key.
+      Probably the most widely used <a href="#symmetric">symmetric cipher</a>
+      ever devised. DES has been a US government standard for their own use
+      (only for unclassified data), and for some regulated industries such as
+      banking, since the late 70's. It is now being replaced by <a
+      href="#AES">AES</a>.
+      <p><a href="politics.html#desnotsecure">DES is seriously insecure
+      against current attacks.</a></p>
+      <p><a href="#FreeSWAN">Linux FreeS/WAN</a> does not include DES, even
+      though the RFCs specify it. <b>We strongly recommend that single DES
+      not be used.</b></p>
+      <p>See also <a href="#3DES">3DES</a> and <a href="#DESX">DESX</a>,
+      stronger ciphers based on DES.</p>
+    </dd>
+  <dt><a name="DESX">DESX</a></dt>
+    <dd>An improved <a href="#DES">DES</a> suggested by Ron Rivest of RSA
+      Data Security. It XORs extra key material into the text before and
+      after applying the DES cipher.
+      <p>This is not required by the <a href="#IPSEC">IPsec</a> RFCs and not
+      currently used in <a href="#FreeSWAN">Linux FreeS/WAN</a>. DESX would
+      be the easiest additional transform to add; there would be very little
+      code to write. It would be much faster than 3DES and almost certainly
+      more secure than DES. However, since it is not in the RFCs other IPsec
+      implementations cannot be expected to have it.</p>
+    </dd>
+  <dt>DH</dt>
+    <dd>see <a href="#DH">Diffie-Hellman</a></dd>
+  <dt><a name="DHCP">DHCP</a></dt>
+    <dd><strong>D</strong>ynamic <strong>H</strong>ost
+      <strong>C</strong>onfiguration <strong>P</strong>rotocol, a method of
+      assigning <a href="#dynamic">dynamic IP addresses</a>, and providing
+      additional information such as addresses of DNS servers and of
+      gateways. See this <a href="http://www.dhcp.org">DHCP resource
+    page.</a></dd>
+  <dt><a name="DH">Diffie-Hellman (DH) key exchange protocol</a></dt>
+    <dd>A protocol that allows two parties without any initial shared secret
+      to create one in a manner immune to eavesdropping. Once they have done
+      this, they can communicate privately by using that shared secret as a
+      key for a block cipher or as the basis for key exchange.
+      <p>The protocol is secure against all <a href="#passive">passive
+      attacks</a>, but it is not at all resistant to active <a
+      href="#middle">man-in-the-middle attacks</a>. If a third party can
+      impersonate Bob to Alice and vice versa, then no useful secret can be
+      created. Authentication of the participants is a prerequisite for safe
+      Diffie-Hellman key exchange. IPsec can use any of several <a
+      href="#authentication">authentication</a> mechanisims. Those supported
+      by FreeS/WAN are discussed in our <a
+      href="config.html#choose">configuration</a> section.</p>
+      <p>The Diffie-Hellman key exchange is based on the <a
+      href="#dlog">discrete logarithm</a> problem and is secure unless
+      someone finds an efficient solution to that problem.</p>
+      <p>Given a prime <var>p</var> and generator <var>g</var> (explained
+      under <a href="#dlog">discrete log</a> below), Alice:</p>
+      <ul>
+        <li>generates a random number <var>a</var></li>
+        <li>calculates <var>A = g^a modulo p</var></li>
+        <li>sends <var>A</var> to Bob</li>
+      </ul>
+      <p>Meanwhile Bob:</p>
+      <ul>
+        <li>generates a random number <var>b</var></li>
+        <li>calculates <var>B = g^b modulo p</var></li>
+        <li>sends <var>B</var> to Alice</li>
+      </ul>
+      <p>Now Alice and Bob can both calculate the shared secret <var>s =
+      g^(ab)</var>. Alice knows <var>a</var> and <var>B</var>, so she
+      calculates <var>s = B^a</var>. Bob knows <var>A</var> and <var>b</var>
+      so he calculates <var>s = A^b</var>.</p>
+      <p>An eavesdropper will know <var>p</var> and <var>g</var> since these
+      are made public, and can intercept <var>A</var> and <var>B</var> but,
+      short of solving the <a href="#dlog">discrete log</a> problem, these do
+      not let him or her discover the secret <var>s</var>.</p>
+    </dd>
+  <dt><a name="signature">Digital signature</a></dt>
+    <dd>Sender:
+      <ul>
+        <li>calculates a <a href="#digest">message digest</a> of a
+        document</li>
+        <li>encrypts the digest with his or her private key, using some <a
+          href="#public">public key cryptosystem</a>.</li>
+        <li>attaches the encrypted digest to the document as a signature</li>
+      </ul>
+      <p>Receiver:</p>
+      <ul>
+        <li>calculates a digest of the document (not including the
+        signature)</li>
+        <li>decrypts the signature with the signer's public key</li>
+        <li>verifies that the two results are identical</li>
+      </ul>
+      <p>If the public-key system is secure and the verification succeeds,
+      then the receiver knows</p>
+      <ul>
+        <li>that the document was not altered between signing and
+        verification</li>
+        <li>that the signer had access to the private key</li>
+      </ul>
+      <p>Such an encrypted message digest can be treated as a signature since
+      it cannot be created without <em>both</em> the document <em>and</em>
+      the private key which only the sender should possess. The <a
+      href="web.html#legal">legal issues</a> are complex, but several
+      countries are moving in the direction of legal recognition for digital
+      signatures.</p>
+    </dd>
+  <dt><a name="dlog">discrete logarithm problem</a></dt>
+    <dd>The problem of finding logarithms in a finite field. Given a field
+      defintion (such definitions always include some operation analogous to
+      multiplication) and two numbers, a base and a target, find the power
+      which the base must be raised to in order to yield the target.
+      <p>The discrete log problem is the basis of several cryptographic
+      systems, including the <a href="#DH">Diffie-Hellman</a> key exchange
+      used in the <a href="#IKE">IKE</a> protocol. The useful property is
+      that exponentiation is relatively easy but the inverse operation,
+      finding the logarithm, is hard. The cryptosystems are designed so that
+      the user does only easy operations (exponentiation in the field) but an
+      attacker must solve the hard problem (discrete log) to crack the
+      system.</p>
+      <p>There are several variants of the problem for different types of
+      field. The IKE/Oakley key determination protocol uses two variants,
+      either over a field modulo a prime or over a field defined by an
+      elliptic curve. We give an example modulo a prime below. For the
+      elliptic curve version, consult an advanced text such as <a
+      href="biblio.html#handbook">Handbook of Applied Cryptography</a>.</p>
+      <p>Given a prime <var>p</var>, a generator <var>g</var> for the field
+      modulo that prime, and a number <var>x</var> in the field, the problem
+      is to find <var>y</var> such that <var>g^y = x</var>.</p>
+      <p>For example, let p = 13. The field is then the integers from 0 to
+      12. Any integer equals one of these modulo 13. That is, the remainder
+      when any integer is divided by 13 must be one of these.</p>
+      <p>2 is a generator for this field.  That is, the powers of two modulo
+      13 run through all the non-zero numbers in the field. Modulo 13 we
+      have:</p>
+      <pre>          y      x
+        2^0  ==  1
+        2^1  ==  2
+        2^2  ==  4
+        2^3  ==  8
+        2^4  ==  3 that is, the remainder from 16/13 is 3
+        2^5  ==  6          the remainder from 32/13 is 6
+        2^6  == 12 and so on
+        2^7  == 11
+        2^8  ==  9
+        2^9  ==  5
+        2^10 == 10
+        2^11 ==  7
+        2^12 ==  1</pre>
+      <p>Exponentiation in such a field is not difficult. Given, say,
+      <nobr><var>y = 11</var>,</nobr>calculating <nobr><var>x =
+      7</var></nobr>is straightforward. One method is just to calculate
+      <nobr><var>2^11 = 2048</var>,</nobr>then <nobr><var>2048 mod 13 ==
+      7</var>.</nobr>When the field is modulo a large prime (say a few 100
+      digits) you need a silghtly cleverer method and even that is moderately
+      expensive in computer time, but the calculation is still not
+      problematic in any basic way.</p>
+      <p>The discrete log problem is the reverse. In our example, given
+      <nobr><var>x = 7</var>,</nobr>find the logarithm <nobr><var>y =
+      11</var>.</nobr>When the field is modulo a large prime (or is based on
+      a suitable elliptic curve), this is indeed problematic. No solution
+      method that is not catastrophically expensive is known. Quite a few
+      mathematicians have tackled this problem. No efficient method has been
+      found and mathematicians do not expect that one will be. It seems
+      likely no efficient solution to either of the main variants the
+      discrete log problem exists.</p>
+      <p>Note, however, that no-one has proven such methods do not exist. If
+      a solution to either variant were found, the security of any crypto
+      system using that variant would be destroyed.  This is one reason <a
+      href="#IKE">IKE</a> supports two variants. If one is broken, we can
+      switch to the other.</p>
+    </dd>
+  <dt><a name="discretionary">discretionary access control</a></dt>
+    <dd>access control mechanisms controlled by the user, for example Unix
+      rwx file permissions. These contrast with <a
+      href="#mandatory">mandatory access controls</a>.</dd>
+  <dt><a name="DNS">DNS</a></dt>
+    <dd><b>D</b>omain <b>N</b>ame <b>S</b>ervice, a distributed database
+      through which names are associated with numeric addresses and other
+      information in the Internet Protocol Suite. See also the <a
+      href="background.html#dns.background">DNS background</a> section of our
+      documentation.</dd>
+  <dt>DOS attack</dt>
+    <dd>see <a href="#DOS">Denial Of Service</a> attack</dd>
+  <dt><a name="dynamic">dynamic IP address</a></dt>
+    <dd>an IP address which is automatically assigned, either by <a
+      href="#DHCP">DHCP</a> or by some protocol such as <a
+      href="#PPP">PPP</a> or <a href="#PPPoE">PPPoE</a> which the machine
+      uses to connect to the Internet. This is the opposite of a <a
+      href="#static">static IP address</a>, pre-set on the machine
+    itself.</dd>
+  <dt><a name="E">E</a></dt>
+  <dt><a name="EAR">EAR</a></dt>
+    <dd>The US government's <b>E</b>xport <b>A</b>dministration
+      <b>R</b>egulations, administered by the <a href="#BXA">Bureau of Export
+      Administration</a>. These have replaced the earlier <a
+      href="#ITAR">ITAR</a> regulations as the controls on export of
+      cryptography.</dd>
+  <dt><a name="ECB">ECB mode</a></dt>
+    <dd><b>E</b>lectronic <b>C</b>ode<b>B</b>ook mode, the simplest way to
+      use a block cipher. See <a href="#mode">Cipher Modes</a>.</dd>
+  <dt><a name="EDE">EDE</a></dt>
+    <dd>The sequence of operations normally used in either the three-key
+      variant of <a href="#3DES">triple DES</a> used in <a
+      href="#IPSEC">IPsec</a> or the <a href="#2key">two-key</a> variant used
+      in some other systems.
+      <p>The sequence is:</p>
+      <ul>
+        <li><b>E</b>ncrypt with key1</li>
+        <li><b>D</b>ecrypt with key2</li>
+        <li><b>E</b>ncrypt with key3</li>
+      </ul>
+      <p>For the two-key version, key1=key3.</p>
+      <p>The "advantage" of this EDE order of operations is that it makes it
+      simple to interoperate with older devices offering only single DES. Set
+      key1=key2=key3 and you have the worst of both worlds, the overhead of
+      triple DES with the "security" of single DES. Since both the <a
+      href="politics.html#desnotsecure">security of single DES</a> and the
+      overheads of triple DES are seriously inferior to many other ciphers,
+      this is a spectacularly dubious "advantage".</p>
+    </dd>
+  <dt><a name="Entrust">Entrust</a></dt>
+    <dd>A Canadian company offerring enterprise <a href="#PKI">PKI</a>
+      products using <a href="#CAST128">CAST-128</a> symmetric crypto, <a
+      href="#RSA">RSA</a> public key and <a href="#X509">X.509</a>
+      directories. <a href="http://www.entrust.com">Web site</a></dd>
+  <dt><a name="EFF">EFF</a></dt>
+    <dd><a href="http://www.eff.org">Electronic Frontier Foundation</a>, an
+      advocacy group for civil rights in cyberspace.</dd>
+  <dt><a name="encryption">Encryption</a></dt>
+    <dd>Techniques for converting a readable message (<a
+      href="#plaintext">plaintext</a>) into apparently random material (<a
+      href="#ciphertext">ciphertext</a>) which cannot be read if intercepted.
+      A key is required to read the message.
+      <p>Major variants include <a href="#symmetric">symmetric</a> encryption
+      in which sender and receiver use the same secret key and <a
+      href="#public">public key</a> methods in which the sender uses one of a
+      matched pair of keys and the receiver uses the other. Many current
+      systems, including <a href="#IPSEC">IPsec</a>, are <a
+      href="#hybrid">hybrids</a> combining the two techniques.</p>
+    </dd>
+  <dt><a name="ESP">ESP</a></dt>
+    <dd><b>E</b>ncapsulated <b>S</b>ecurity <b>P</b>ayload, the <a
+      href="#IPSEC">IPsec</a> protocol which provides <a
+      href="#encryption">encryption</a>. It can also provide <a
+      href="#authentication">authentication</a> service and may be used with
+      null encryption (which we do not recommend). For details see our <a
+      href="ipsec.html#ESP.ipsec">IPsec</a> document and/or RFC 2406.</dd>
+  <dt><a name="#extruded">Extruded subnet</a></dt>
+    <dd>A situation in which something IP sees as one network is actually in
+      two or more places.
+      <p>For example, the Internet may route all traffic for a particular
+      company to that firm's corporate gateway. It then becomes the company's
+      problem to get packets to various machines on their <a
+      href="#subnet">subnets</a> in various departments. They may decide to
+      treat a branch office like a subnet, giving it IP addresses "on" their
+      corporate net. This becomes an extruded subnet.</p>
+      <p>Packets bound for it are delivered to the corporate gateway, since
+      as far as the outside world is concerned, that subnet is part of the
+      corporate network. However, instead of going onto the corporate LAN (as
+      they would for, say, the accounting department) they are then
+      encapsulated and sent back onto the Internet for delivery to the branch
+      office.</p>
+      <p>For information on doing this with Linux FreeS/WAN, look in our <a
+      href="adv_config.html#extruded.config">advanced configuration</a>
+      section.</p>
+    </dd>
+  <dt>Exhaustive search</dt>
+    <dd>See <a href="#brute">brute force attack</a>.</dd>
+  <dt><a name="F">F</a></dt>
+  <dt><a name="FIPS">FIPS</a></dt>
+    <dd><b>F</b>ederal <b>I</b>nformation <b>P</b>rocessing <b>S</b>tandard,
+      the US government's standards for products it buys. These are issued by
+      <a href="#NIST">NIST</a>. Among other things, <a href="#DES">DES</a>
+      and <a href="#SHA">SHA</a> are defined in FIPS documents. NIST have a
+      <a href="http://www.itl.nist.gov/div897/pubs">FIPS home page</a>.</dd>
+  <dt><a name="FSF">Free Software Foundation (FSF)</a></dt>
+    <dd>An organisation to promote free software, free in the sense of these
+      quotes from their web pages</dd>
+    <dd>
+      <blockquote>
+        "Free software" is a matter of liberty, not price. To understand the
+        concept, you should think of "free speech", not "free beer."
+        <p>"Free software" refers to the users' freedom to run, copy,
+        distribute, study, change and improve the software.</p>
+      </blockquote>
+      <p>See also <a href="#GNU">GNU</a>, <a href="#GPL">GNU General Public
+      License</a>, and <a href="http://www.fsf.org">the FSF site</a>.</p>
+    </dd>
+  <dt>FreeS/WAN</dt>
+    <dd>see <a href="#FreeSWAN">Linux FreeS/WAN</a></dd>
+  <dt><a name="fullnet">Fullnet</A></dt>
+    <dd>The CIDR block containing all IPs of its IP version. 
+    The <A HREF="#IPv4">IPv4</A> fullnet is written 0.0.0.0/0. 
+    Also known as "all" and "default",
+    fullnet may be used in a routing table 
+    to specify a default route, 
+    and in a FreeS/WAN 
+    <A HREF="policygroups.html#policygroups">policy group</A> file to 
+    specify a default IPsec policy.</dd>
+  <dt>FSF</dt>
+    <dd>see <a href="#FSF">Free software Foundation</a></dd>
+  <dt><a name="G">G</a></dt>
+  <dt><a name="GCHQ">GCHQ</a></dt>
+    <dd><a href="http://www.gchq.gov.uk">Government Communications
+      Headquarters</a>, the British organisation for <a
+      href="#SIGINT">signals intelligence</a>.</dd>
+  <dt>generator of a prime field</dt>
+    <dd>see <a href="#dlog">discrete logarithm problem</a></dd>
+  <dt><a name="GILC">GILC</a></dt>
+    <dd><a href="http://www.gilc.org">Global Internet Liberty Campaign</a>,
+      an international organisation advocating, among other things, free
+      availability of cryptography. They have a <a
+      href="http://www.gilc.org/crypto/wassenaar">campaign</a> to remove
+      cryptographic software from the <a href="#Wassenaar.gloss">Wassenaar
+      Arrangement</a>.</dd>
+  <dt>Global Internet Liberty Campaign</dt>
+    <dd>see <a href="#GILC">GILC</a>.</dd>
+  <dt><a name="GTR">Global Trust Register</a></dt>
+    <dd>An attempt to create something like a <a href="#rootCA">root CA</a>
+      for <a href="#PGP">PGP</a> by publishing both <a
+      href="biblio.html#GTR">as a book</a> and <a
+      href="http://www.cl.cam.ac.uk/Research/Security/Trust-Register"> on the
+      web</a> the fingerprints of a set of verified keys for well-known users
+      and organisations.</dd>
+  <dt><a name="GMP">GMP</a></dt>
+    <dd>The <b>G</b>NU <b>M</b>ulti-<b>P</b>recision library code, used in <a
+      href="#FreeSWAN">Linux FreeS/WAN</a> by <a href="#Pluto">Pluto</a> for
+      <a href="#public">public key</a> calculations. See the <a
+      href="http://www.swox.com/gmp">GMP  home page</a>.</dd>
+  <dt><a name="GNU">GNU</a></dt>
+    <dd><b>G</b>NU's <b>N</b>ot <b>U</b>nix, the <a href="#FSF">Free Software
+      Foundation's</a> project aimed at creating a free system with at least
+      the capabilities of Unix. <a href="#Linux">Linux</a> uses GNU utilities
+      extensively.</dd>
+  <dt><a name="#GOST">GOST</a></dt>
+    <dd>a Soviet government standard <a href="#block">block cipher</a>. <a
+      href="biblio.html#schneier">Applied Cryptography</a> has details.</dd>
+  <dt>GPG</dt>
+    <dd>see <a href="#GPG">GNU Privacy Guard</a></dd>
+  <dt><a name="GPL">GNU General Public License</a>(GPL, copyleft)</dt>
+    <dd>The license developed by the <a href="#FSF">Free Software
+      Foundation</a> under which <a href="#Linux">Linux</a>, <a
+      href="#FreeSWAN">Linux FreeS/WAN</a> and many other pieces of software
+      are distributed. The license allows anyone to redistribute and modify
+      the code, but forbids anyone from distributing executables without
+      providing access to source code. For more details see the file <a
+      href="../COPYING">COPYING</a> included with GPLed source distributions,
+      including ours, or <a href="http://www.fsf.org/copyleft/gpl.html"> the
+      GNU site's GPL page</a>.</dd>
+  <dt><a name="GPG">GNU Privacy Guard</a></dt>
+    <dd>An open source implementation of Open <a href="#PGP">PGP</a> as
+      defined in RFC 2440. See their <a href="http://www.gnupg.org">web
+      site</a></dd>
+  <dt>GPL</dt>
+    <dd>see <a href="#GPL">GNU General Public License</a>.</dd>
+  <dt><a name="H">H</a></dt>
+  <dt><a name="hash">Hash</a></dt>
+    <dd>see <a href="#digest">message digest</a></dd>
+  <dt><a name="HMAC">Hashed Message Authentication Code (HMAC)</a></dt>
+    <dd>using keyed <a href="#digest">message digest</a> functions to
+      authenticate a message. This differs from other uses of these functions:
+      <ul>
+        <li>In normal usage, the hash function's internal variable are
+          initialised in some standard way. Anyone can reproduce the hash to
+          check that the message has not been altered.</li>
+        <li>For HMAC usage, you initialise the internal variables from the
+          key. Only someone with the key can reproduce the hash. A successful
+          check of the hash indicates not only that the message is unchanged
+          but also that the creator knew the key.</li>
+      </ul>
+      <p>The exact techniques used in <a href="#IPSEC">IPsec</a> are defined
+      in RFC 2104. They are referred to as HMAC-MD5-96 and HMAC-SHA-96
+      because they output only 96 bits of the hash. This makes some attacks
+      on the hash functions harder.</p>
+    </dd>
+  <dt>HMAC</dt>
+    <dd>see <a href="#HMAC">Hashed Message Authentication Code</a></dd>
+  <dt>HMAC-MD5-96</dt>
+    <dd>see <a href="#HMAC">Hashed Message Authentication Code</a></dd>
+  <dt>HMAC-SHA-96</dt>
+    <dd>see <a href="#HMAC">Hashed Message Authentication Code</a></dd>
+  <dt><a name="hybrid">Hybrid cryptosystem</a></dt>
+    <dd>A system using both <a href="#public">public key</a> and <a
+      href="#symmetric">symmetric cipher</a> techniques. This works well.
+      Public key methods provide key management and <a
+      href="#signature">digital signature</a> facilities which are not
+      readily available using symmetric ciphers. The symmetric cipher,
+      however, can do the bulk of the encryption work much more efficiently
+      than public key methods.</dd>
+  <dt><a name="I">I</a></dt>
+  <dt><a name="IAB">IAB</a></dt>
+    <dd><a href="http://www.iab.org/iab">Internet Architecture Board</a>.</dd>
+  <dt><a name="ICMP.gloss">ICMP</a></dt>
+    <dd><strong>I</strong>nternet <strong>C</strong>ontrol
+      <strong>M</strong>essage <strong>P</strong>rotocol. This is used for
+      various IP-connected devices to manage the network.</dd>
+  <dt><a name="IDEA">IDEA</a></dt>
+    <dd><b>I</b>nternational <b>D</b>ata <b>E</b>ncrypion <b>A</b>lgorithm,
+      developed in Europe as an alternative to exportable American ciphers
+      such as <a href="#DES">DES</a> which were <a href="#desnotsecure">too
+      weak for serious use</a>. IDEA is a <a href="#block">block cipher</a>
+      using 64-bit blocks and 128-bit keys, and is used in products such as
+      <a href="#PGP">PGP</a>.
+      <p>IDEA is not required by the <a href="#IPSEC">IPsec</a> RFCs and not
+      currently used in <a href="#FreeSWAN">Linux FreeS/WAN</a>.</p>
+      <p>IDEA is patented and, with strictly limited exceptions for personal
+      use, using it requires a license from <a
+      href="http://www.ascom.com">Ascom</a>.</p>
+    </dd>
+  <dt><a name="IEEE">IEEE</a></dt>
+    <dd><a href="http://www.ieee.org">Institute of Electrical and Electronic
+      Engineers</a>, a professional association which, among other things,
+      sets some technical standards</dd>
+  <dt><a name="IESG">IESG</a></dt>
+    <dd><a href="http://www.iesg.org">Internet Engineering Steering
+    Group</a>.</dd>
+  <dt><a name="IETF">IETF</a></dt>
+    <dd><a href="http://www.ietf.org">Internet Engineering Task Force</a>,
+      the umbrella organisation whose various working groups make most of the
+      technical decisions for the Internet. The IETF <a
+      href="http://www.ietf.org/html.charters/ipsec-charter.html"> IPsec
+      working group</a> wrote the <a href="#RFC">RFCs</a> we are
+    implementing.</dd>
+  <dt><a name="IKE">IKE</a></dt>
+    <dd><b>I</b>nternet <b>K</b>ey <b>E</b>xchange, based on the <a
+      href="#DH">Diffie-Hellman</a> key exchange protocol. For details, see
+      RFC 2409 and our <a href="ipsec.html">IPsec</a> document. IKE is
+      implemented in <a href="#FreeSWAN">Linux FreeS/WAN</a> by the <a
+      href="#Pluto">Pluto daemon</a>.</dd>
+  <dt>IKE v2</dt>
+    <dd>A proposed replacement for <a href="#IKE">IKE</a>. There are other
+      candidates, such as <a href="#JFK">JFK</a>, and at time of writing
+      (March 2002) the choice between them has not yet been made and does not
+      appear imminent.</dd>
+  <dt><a name="iOE">iOE</a></dt>
+    <dd>See <A HREF="#initiate-only">Initiate-only opportunistic 
+     encryption</A>.</dd>
+  <dt><a name="IP">IP</a></dt>
+    <dd><b>I</b>nternet <b>P</b>rotocol.</dd>
+  <dt><a name="masq">IP masquerade</a></dt>
+    <dd>A mostly obsolete term for a method of allowing multiple machines to
+      communicate over the Internet when only one IP address is available for
+      their use. The more current term is Network Address Translation or <a
+      href="#NAT.gloss">NAT</a>.</dd>
+  <dt><a name="IPng">IPng</a></dt>
+    <dd>"IP the Next Generation", see <a href="#ipv6.gloss">IPv6</a>.</dd>
+  <dt><a name="IPv4">IPv4</a></dt>
+    <dd>The current version of the <a href="#IP">Internet protocol
+    suite</a>.</dd>
+  <dt><a name="ipv6.gloss">IPv6 (IPng)</a></dt>
+    <dd>Version six of the <a href="#IP">Internet protocol suite</a>,
+      currently being developed. It will replace the current <a
+      href="#IPv4">version four</a>. IPv6 has <a href="#IPSEC">IPsec</a> as a
+      mandatory component.
+      <p>See this <a
+      href="http://playground.sun.com/pub/ipng/html/ipng-main.html">web
+      site</a> for more details, and our <a
+      href="compat.html#ipv6">compatibility</a> document for information on
+      FreeS/WAN and the Linux implementation of IPv6.</p>
+    </dd>
+  <dt><a name="IPSEC">IPsec</a> or IPSEC</dt>
+    <dd><b>I</b>nternet <b>P</b>rotocol <b>SEC</b>urity, security functions
+      (<a href="#authentication">authentication</a> and <a
+      href="#encryption">encryption</a>) implemented at the IP level of the
+      protocol stack. It is optional for <a href="#IPv4">IPv4</a> and
+      mandatory for <a href="#ipv6.gloss">IPv6</a>.
+      <p>This is the standard <a href="#FreeSWAN">Linux FreeS/WAN</a> is
+      implementing. For more details, see our <a href="ipsec.html">IPsec
+      Overview</a>. For the standards, see RFCs listed in our <a
+      href="rfc.html#RFC">RFCs document</a>.</p>
+    </dd>
+  <dt><a name="IPX">IPX</a></dt>
+    <dd>Novell's Netware protocol tunnelled over an IP link. Our <a
+      href="firewall.html#user.scripts">firewalls</a> document includes an
+      example of using this through an IPsec tunnel.</dd>
+  <dt><a name="ISAKMP">ISAKMP</a></dt>
+    <dd><b>I</b>nternet <b>S</b>ecurity <b>A</b>ssociation and <b>K</b>ey
+      <b>M</b>anagement <b>P</b>rotocol, defined in RFC 2408.</dd>
+  <dt><a name="ITAR">ITAR</a></dt>
+    <dd><b>I</b>nternational <b>T</b>raffic in <b>A</b>rms
+      <b>R</b>egulations, US regulations administered by the State Department
+      which until recently limited export of, among other things,
+      cryptographic technology and software. ITAR still exists, but the
+      limits on cryptography have now been transferred to the <a
+      href="#EAR">Export Administration Regulations</a> under the Commerce
+      Department's <a href="#BXA">Bureau of Export Administration</a>.</dd>
+  <dt>IV</dt>
+    <dd>see <a href="#IV">Initialisation vector</a></dd>
+  <dt><a name="IV">Initialisation Vector (IV)</a></dt>
+    <dd>Some cipher <a href="#mode">modes</a>, including the <a
+      href="#CBC">CBC</a> mode which IPsec uses, require some extra data at
+      the beginning. This data is called the initialisation vector. It need
+      not be secret, but should be different for each message. Its function
+      is to prevent messages which begin with the same text from encrypting
+      to the same ciphertext. That might give an analyst an opening, so it is
+      best prevented.</dd>
+  <dt><a name="initiate-only">Initiate-only opportunistic 
+  encryption (iOE)</a></dt>
+    <dd>A form of 
+     <A HREF="#carpediem">opportunistic encryption</A> (OE) in which 
+     a host proposes opportunistic connections, but lacks the reverse DNS
+     records necessary to support incoming opportunistic connection requests.
+     Common among hosts on cable or pppoe connections where the system 
+     administrator does not have write access to the DNS reverse map
+     for the host's external IP.
+      <p>Configuring for initiate-only opportunistic encryption 
+       is described in our
+      <a href="quickstart.html#opp.client">quickstart</a> document.</p>
+    </dd>
+  <dt><a name="J">J</a></dt>
+  <dt><a name="JFK">JFK</a></dt>
+    <dd><strong>J</strong>ust <strong>F</strong>ast <strong>K</strong>eying,
+      a proposed simpler replacement for <a href="#IKE">IKE.</a></dd>
+  <dt><a name="K">K</a></dt>
+  <dt><a name="kernel">Kernel</a></dt>
+    <dd>The basic part of an operating system (e.g. Linux) which controls the
+      hardware and provides services to all other programs.
+      <p>In the Linux release numbering system, an even second digit as in
+      2.<strong>2</strong>.x indicates a stable or production kernel while an
+      odd number as in 2.<strong>3</strong>.x indicates an experimental or
+      development kernel. Most users should run a recent kernel version from
+      the production series. The development kernels are primarily for people
+      doing kernel development. Others should consider using development
+      kernels only if they have an urgent need for some feature not yet
+      available in production kernels.</p>
+    </dd>
+  <dt>Keyed message digest</dt>
+    <dd>See <a href="#HMAC">HMAC</a>.</dd>
+  <dt>Key length</dt>
+    <dd>see <a href="#brute">brute force attack</a></dd>
+  <dt><a name="KLIPS">KLIPS</a></dt>
+    <dd><b>K</b>erne<b>l</b> <b>IP</b> <b>S</b>ecurity, the <a
+      href="#FreeSWAN">Linux FreeS/WAN</a> project's changes to the <a
+      href="#Linux">Linux</a> kernel to support the <a
+      href="#IPSEC">IPsec</a> protocols.</dd>
+  <dt><a name="L">L</a></dt>
+  <dt><a name="LDAP">LDAP</a></dt>
+    <dd><b>L</b>ightweight <b>D</b>irectory <b>A</b>ccess <b>P</b>rotocol,
+      defined in RFCs 1777 and 1778,  a method of accessing information
+      stored in directories. LDAP is used by several <a href="#PKI">PKI</a>
+      implementations, often with X.501 directories and <a
+      href="#X509">X.509</a> certificates. It may also be used by <a
+      href="#IPSEC">IPsec</a> to obtain key certifications from those PKIs.
+      This is not yet implemented in <a href="#FreeSWAN">Linux
+    FreeS/WAN</a>.</dd>
+  <dt><a name="LIBDES">LIBDES</a></dt>
+    <dd>A publicly available library of <a href="#DES">DES</a> code, written
+      by Eric Young, which <a href="#FreeSWAN">Linux FreeS/WAN</a> uses in
+      both <a href="#KLIPS">KLIPS</a> and <a href="#Pluto">Pluto</a>.</dd>
+  <dt><a name="Linux">Linux</a></dt>
+    <dd>A freely available Unix-like operating system based on a kernel
+      originally written for the Intel 386 architecture by (then) student
+      Linus Torvalds. Once his 32-bit kernel was available, the <a
+      href="#GNU">GNU</a> utilities made it a usable system and contributions
+      from many others led to explosive growth.
+      <p>Today Linux is a complete Unix replacement available for several CPU
+      architectures -- Intel, DEC/Compaq Alpha, Power PC, both 32-bit SPARC
+      and the 64-bit UltraSPARC, SrongARM, . . . -- with support for multiple
+      CPUs on some architectures.</p>
+      <p><a href="#FreeSWAN">Linux FreeS/WAN</a> is intended to run on all
+      CPUs supported by Linux and is known to work on several. See our <a
+      href="compat.html#CPUs">compatibility</a> section for a list.</p>
+    </dd>
+  <dt><a name="FreeSWAN">Linux FreeS/WAN</a></dt>
+    <dd>Our implementation of the <a href="#IPSEC">IPsec</a> protocols,
+      intended to be freely redistributable source code with <a href="#GPL">a
+      GNU GPL license</a> and no constraints under US or other <a
+      href="politics.html#exlaw">export laws</a>. Linux FreeS/WAN is intended
+      to interoperate with other <a href="#IPSEC">IPsec</a> implementations.
+      The name is partly taken, with permission, from the <a
+      href="#SWAN">S/WAN</a> multi-vendor IPsec compatability effort. Linux
+      FreeS/WAN has two major components, <a href="#KLIPS">KLIPS</a> (KerneL
+      IPsec Support) and the <a href="#Pluto">Pluto</a> daemon which manages
+      the whole thing.
+      <p>See our <a href="ipsec.html">IPsec section</a> for more detail. For
+      the code see our <a href="http://freeswan.org"> primary site</a> or one
+      of the mirror sites on <a href="intro.html#mirrors">this list</a>.</p>
+    </dd>
+  <dt><a name="LSM">Linux Security Modules (LSM)</a></dt>
+    <dd>a project to create an interface in the Linux kernel that supports
+      plug-in modules for various security policies.
+      <p>This allows multiple security projects to take different approaches
+      to security enhancement without tying the kernel down to one particular
+      approach. As I understand the history, several projects were pressing
+      Linus to incorporate their changes, the various sets of changes were
+      incompatible, and his answer was more-or-less "a plague on all your
+      houses; I'll give you an interface, but I won't incorporate
+      anything".</p>
+      <p>It seems to be working. There is a fairly active <a
+      href="http://mail.wirex.com/mailman/listinfo/linux-security-module">LSM
+      mailing list</a>, and several projects are already using the
+      interface.</p>
+    </dd>
+  <dt>LSM</dt>
+    <dd>see <a href="#LSM">Linux Security Modules</a></dd>
+  <dt><a name="M">M</a></dt>
+  <dt><a name="list">Mailing list</a></dt>
+    <dd>The <a href="#FreeSWAN">Linux FreeS/WAN</a> project has several
+      public email lists for bug reports and software development
+      discussions. See our document on <a href="mail.html">mailing
+    lists</a>.</dd>
+  <dt><a name="middle">Man-in-the-middle attack</a></dt>
+    <dd>An <a href="#active">active attack</a> in which the attacker
+      impersonates each of the legitimate players in a protocol to the other.
+      <p>For example, if <a href="#alicebob">Alice and Bob</a> are
+      negotiating a key via the <a href="#DH">Diffie-Hellman</a> key
+      agreement, and are not using <a
+      href="#authentication">authentication</a> to be certain they are
+      talking to each other, then an attacker able to insert himself in the
+      communication path can deceive both players.</p>
+      <p>Call the attacker Mallory. For Bob, he pretends to be Alice. For
+      Alice, he pretends to be Bob. Two keys are then negotiated,
+      Alice-to-Mallory and Bob-to-Mallory. Alice and Bob each think the key
+      they have is Alice-to-Bob.</p>
+      <p>A message from Alice to Bob then goes to Mallory who decrypts it,
+      reads it and/or saves a copy, re-encrypts using the Bob-to-Mallory key
+      and sends it along to Bob. Bob decrypts successfully and sends a reply
+      which Mallory decrypts, reads, re-encrypts and forwards to Alice.</p>
+      <p>To make this attack effective, Mallory must</p>
+      <ul>
+        <li>subvert some part of the network in some way that lets him carry
+          out the deception<br>
+          possible targets: DNS, router, Alice or Bob's machine, mail server,
+          ...</li>
+        <li>beat any authentication mechanism Alice and Bob use<br>
+          strong authentication defeats the attack entirely; this is why <a
+          href="#IKE">IKE</a> requires authentication</li>
+        <li>work in real time, delivering messages without introducing a
+          delay large enough to alert the victims<br>
+          not hard if Alice and Bob are using email; quite difficult in some
+          situations.</li>
+      </ul>
+      <p>If he manages it, however, it is devastating. He not only gets to
+      read all the messages; he can alter messages, inject his own, forge
+      anything he likes, . . . In fact, he controls the communication
+      completely.</p>
+    </dd>
+  <dt><a name="mandatory">mandatory access control</a></dt>
+    <dd>access control mechanisims which are not settable by the user (see <a
+      href="#discretionary">discretionary access control</a>), but are
+      enforced by the system.
+      <p>For example, a document labelled "secret, zebra" might be readable
+      only by someone with secret clearance working on Project Zebra.
+      Ideally, the system will prevent any transfer outside those boundaries.
+      For example, even if you can read it, you should not be able to e-mail
+      it (unless the recipient is appropriately cleared) or print it (unless
+      certain printers are authorised for that classification).</p>
+      <p>Mandatory access control is a required feature for some levels of <a
+      href="#rainbow">Rainbow Book</a> or <a href="#cc">Common Criteria</a>
+      classification, but has not been widely used outside the military and
+      government. There is a good discussion of the issues in Anderson's <a
+      href="biblio.html#anderson">Security Engineering</a>.</p>
+      <p>The <a href="#SElinux">Security Enhanced Linux</a> project is adding
+      mandatory access control to Linux.</p>
+    </dd>
+  <dt><a name="manual">Manual keying</a></dt>
+    <dd>An IPsec mode in which the keys are provided by the administrator. In
+      FreeS/WAN, they are stored in /etc/ipsec.conf. The alternative, <a
+      href="#auto">automatic keying</a>, is preferred in most cases. See this
+      <a href="adv_config.html#man-auto">discussion</a>.</dd>
+  <dt><a name="MD4">MD4</a></dt>
+    <dd><a href="#digest">Message Digest Algorithm</a> Four from Ron Rivest
+      of <a href="#RSAco">RSA</a>. MD4 was widely used a few years ago, but
+      is now considered obsolete. It has been replaced by its descendants <a
+      href="#MD5">MD5</a> and <a href="#SHA">SHA</a>.</dd>
+  <dt><a name="MD5">MD5</a></dt>
+    <dd><a href="#digest">Message Digest Algorithm</a> Five from Ron Rivest
+      of <a href="#RSAco">RSA</a>, an improved variant of his <a
+      href="#MD4">MD4</a>. Like MD4, it produces a 128-bit hash. For details
+      see RFC 1321.
+      <p>MD5 is one of two message digest algorithms available in IPsec. The
+      other is <a href="#SHA">SHA</a>. SHA produces a longer hash and is
+      therefore more resistant to <a href="#birthday">birthday attacks</a>,
+      but this is not a concern for IPsec. The <a href="#HMAC">HMAC</a>
+      method used in IPsec is secure even if the underlying hash is not
+      particularly strong against this attack.</p>
+      <p>Hans Dobbertin found a weakness in MD5, and people often ask whether
+      this means MD5 is unsafe for IPsec. It doesn't. The IPsec RFCs discuss
+      Dobbertin's attack and conclude that it does not affect MD5 as used for
+      HMAC in IPsec.</p>
+    </dd>
+  <dt><a name="meet">Meet-in-the-middle attack</a></dt>
+    <dd>A divide-and-conquer attack which breaks a cipher into two parts,
+      works against each separately, and compares results. Probably the best
+      known example is an attack on double DES. This applies in principle to
+      any pair of block ciphers, e.g. to an encryption system using, say,
+      CAST-128 and Blowfish, but we will describe it for double DES.
+      <p>Double DES encryption and decryption can be written:</p>
+      <pre>        C = E(k2,E(k1,P))
+        P = D(k1,D(k2,C))</pre>
+      <p>Where C is ciphertext, P is plaintext, E is encryption, D is
+      decryption, k1 is one key, and k2 is the other key. If we know a P, C
+      pair, we can try and find the keys with a brute force attack, trying
+      all possible k1, k2 pairs. Since each key is 56 bits, there are
+      2<sup>112</sup> such pairs and this attack is painfully inefficient.</p>
+      <p>The meet-in-the middle attack re-writes the equations to calculate a
+      middle value M:</p>
+      <pre>        M = E(k1,P)
+        M = D(k2,C)</pre>
+      <p>Now we can try some large number of D(k2,C) decryptions with various
+      values of k2 and store the results in a table. Then start doing E(k1,P)
+      encryptions, checking each result to see if it is in the table.</p>
+      <p>With enough table space, this breaks double DES with
+      <nobr>2<sup>56</sup> + 2<sup>56</sup> = 2<sup>57</sup></nobr>work.
+      Against triple DES, you need <nobr>2<sup>56</sup> + 2<sup>112</sup> ~=
+      2<sup>112</sup></nobr>.</p>
+      <p>The memory requirements for such attacks can be prohibitive, but
+      there is a whole body of research literature on methods of reducing
+      them.</p>
+    </dd>
+  <dt><a name="digest">Message Digest Algorithm</a></dt>
+    <dd>An algorithm which takes a message as input and produces a hash or
+      digest of it, a fixed-length set of bits which depend on the message
+      contents in some highly complex manner. Design criteria include making
+      it extremely difficult for anyone to counterfeit a digest or to change
+      a message without altering its digest. One essential property is <a
+      href="#collision">collision resistance</a>. The main applications are
+      in message <a href="#authentication">authentication</a> and <a
+      href="#signature">digital signature</a> schemes. Widely used algorithms
+      include <a href="#MD5">MD5</a> and <a href="#SHA">SHA</a>. In IPsec,
+      message digests are used for <a href="#HMAC">HMAC</a> authentication of
+      packets.</dd>
+  <dt><a name="MTU">MTU</a></dt>
+    <dd><strong>M</strong>aximum <strong>T</strong>ransmission
+      <strong>U</strong>nit, the largest size of packet that can be sent over
+      a link. This is determined by the underlying network, but must be taken
+      account of at the IP level.
+      <p>IP packets, which can be up to 64K bytes each, must be packaged into
+      lower-level packets of the appropriate size for the underlying
+      network(s) and re-assembled on the other end. When a packet must pass
+      over multiple networks, each with its own MTU, and many of the MTUs are
+      unknown to the sender, this becomes a fairly complex problem. See <a
+      href="#pathMTU">path MTU discovery</a> for details.</p>
+      <p>Often the MTU is a few hundred bytes on serial links and 1500 on
+      Ethernet. There are, however, serial link protocols which use a larger
+      MTU to avoid fragmentation at the ethernet/serial boundary, and newer
+      (especially gigabit) Ethernet networks sometimes support much larger
+      packets because these are more efficient in some applications.</p>
+    </dd>
+  <dt><a name="N">N</a></dt>
+  <dt><a name="NAI">NAI</a></dt>
+    <dd><a href="http://www.nai.com">Network Associates</a>, a conglomerate
+      formed from <a href="#PGPI">PGP Inc.</a>, TIS (Trusted Information
+      Systems, a firewall vendor) and McAfee anti-virus products. Among other
+      things, they offer an IPsec-based VPN product.</dd>
+  <dt><a name="NAT.gloss">NAT</a></dt>
+    <dd><b>N</b>etwork <b>A</b>ddress <b>T</b>ranslation, a process by which
+      firewall machines may change the addresses on packets as they go
+      through. For discussion, see our <a
+      href="background.html#nat.background">background</a> section.</dd>
+  <dt><a name="NIST">NIST</a></dt>
+    <dd>The US <a href="http://www.nist.gov"> National Institute of Standards
+      and Technology</a>, responsible for <a href="#FIPS">FIPS standards</a>
+      including <a href="#DES">DES</a> and its replacement, <a
+      href="#AES">AES</a>.</dd>
+  <dt><a name="nonce">Nonce</a></dt>
+    <dd>A <a href="#random">random</a> value used in an <a
+      href="#authentication">authentication</a> protocol.</dd>
+  <dt></dt>
+  <dt><a name="non-routable">Non-routable IP address</a></dt>
+    <dd>An IP address not normally allowed in the "to" or "from" IP address
+      field header of IP packets.
+      <p>Almost invariably, the phrase "non-routable address" means one of
+      the addresses reserved by RFC 1918 for private networks:</p>
+      <ul>
+        <li>10.anything</li>
+        <li>172.x.anything with 16 &lt;= x &lt;= 31</li>
+        <li>192.168.anything</li>
+      </ul>
+      <p>These addresses are commonly used on private networks, e.g. behind a
+      Linux machines doing <a href="#masq">IP masquerade</a>. Machines within
+      the private network can address each other with these addresses. All
+      packets going outside that network, however, have these addresses
+      replaced before they reach the Internet.</p>
+      <p>If any packets using these addresses do leak out, they do not go
+      far. Most routers automatically discard all such packets.</p>
+      <p>Various other addresses -- the 127.0.0.0/8 block reserved for local
+      use, 0.0.0.0, various broadcast and network addresses -- cannot be
+      routed over the Internet, but are not normally included in the meaning
+      when the phrase "non-routable address" is used.</p>
+    </dd>
+  <dt><a name="NSA">NSA</a></dt>
+    <dd>The US <a href="http://www.nsa.gov"> National Security Agency</a>,
+      the American organisation for <a href="#SIGINT">signals
+      intelligence</a>, the protection of US government messages and the
+      interception and analysis of other messages. For details, see Bamford's
+      <a href="biblio.html#puzzle">"The Puzzle Palace"</a>.
+      <p>Some <a
+      href="http://www.gwu.edu/~nsarchiv/NSAEBB/NSAEBB23/index.html">history
+      of NSA</a> documents were declassified in response to a FOIA (Freedom
+      of Information Act) request.</p>
+    </dd>
+  <dt><a name="O">O</a></dt>
+  <dt><a name="oakley">Oakley</a></dt>
+    <dd>A key determination protocol, defined in RFC 2412.</dd>
+  <dt>Oakley groups</dt>
+    <dd>The groups used as the basis of <a href="#DH">Diffie-Hellman</a> key
+      exchange in the Oakley protocol, and in <a href="#IKE">IKE</a>. Four
+      were defined in the original RFC, and a fifth has been <a
+      href="http://www.lounge.org/ike_doi_errata.html">added since</a>.
+      <p>Linux FreeS/WAN currently supports the three groups based on finite
+      fields modulo a prime (Groups 1, 2 and 5) and does not support the
+      elliptic curve groups (3 and 4). For a description of the difference of
+      the types, see <a href="#dlog">discrete logarithms</a>.</p>
+    </dd>
+  <dt><a name="OTP">One time pad</a></dt>
+    <dd>A cipher in which the key is:
+      <ul>
+        <li>as long as the total set of messages to be enciphered</li>
+        <li>absolutely <a href="#random">random</a></li>
+        <li>never re-used</li>
+      </ul>
+      <p>Given those three conditions, it can easily be proved that the
+      cipher is perfectly secure, in the sense that an attacker with
+      intercepted message in hand has no better chance of guessing the
+      message than an attacker who has not intercepted the message and only
+      knows the message length. No such proof exists for any other cipher.</p>
+      <p>There are, however, several problems with this "perfect" cipher.</p>
+      <p>First, it is <strong>wildly impractical</strong> for most
+      applications. Key management is at best difficult, often completely
+      impossible.</p>
+      <p>Second, it is <strong>extremely fragile</strong>. Small changes
+      which violate the conditions listed above do not just weaken the cipher
+      liitle. Quite often they destroy its security completely.</p>
+      <ul>
+        <li>Re-using the pad weakens the cipher to the point where it can be
+          broken with pencil and paper. With a computer, the attack is
+          trivially easy.</li>
+        <li>Using <em>anything</em> less than truly <a
+          href="#random">random</a> numbers <em>completely</em> invalidates
+          the security proof.</li>
+        <li>In particular, using computer-generated pseudo-random numbers may
+          give an extremely weak cipher. It might also produce a good stream
+          cipher, if the pseudo-random generator is both well-designed and
+          properely seeded.</li>
+      </ul>
+      <p>Marketing claims about the "unbreakable" security of various
+      products which somewhat resemble one-time pads are common. Such claims
+      are one of the surest signs of cryptographic <a href="#snake">snake
+      oil</a>; most systems marketed with such claims are worthless.</p>
+      <p>Finally, even if the system is implemented and used correctly, it is
+      <strong>highly vulnerable to a substitution attack</strong>. If an
+      attacker knows some plaintext and has an intercepted message, he can
+      discover the pad.</p>
+      <ul>
+        <li>This does not matter if the attacker is just a <a
+          href="#passive">passive</a> eavesdropper. It gives him no plaintext
+          he didn't already know and we don't care that he learns a pad which
+          we will never re-use.</li>
+        <li>However, an <a href="#active">active</a> attacker who knows the
+          plaintext can recover the pad, then use it to encode with whatever
+          he chooses. If he can get his version delivered instead of yours,
+          this may be a disaster. If you send "attack at dawn", the delivered
+          message can be anything the same length -- perhaps "retreat to
+          east" or "shoot generals".</li>
+        <li>An active attacker with only a reasonable guess at the plaintext
+          can try the same attack. If the guess is correct, this works and
+          the attacker's bogus message is delivered. If the guess is wrong, a
+          garbled message is delivered.</li>
+      </ul>
+      <p>In general then, despite its theoretical perfection, the
+      one-time-pad has very limited practical application.</p>
+      <p>See also the <a href="http://pubweb.nfr.net/~mjr/pubs/otpfaq/">one
+      time pad FAQ</a>.</p>
+    </dd>
+  <dt><a name="carpediem">Opportunistic encryption (OE)</a></dt>
+    <dd>A situation in which any two IPsec-aware machines can secure their
+      communications, without a pre-shared secret and without a common <a
+      href="#PKI">PKI</a> or previous exchange of public keys. This is one of
+      the goals of the Linux FreeS/WAN project, discussed in our <a
+      href="intro.html#goals">introduction</a> section.
+      <p>Setting up for opportunistic encryption is described in our <a
+      href="quickstart.html#quickstart">quickstart</a> document.</p>
+    </dd>
+  <dt><a name="responder">Opportunistic responder</a></dt>
+    <dd>A host which accepts, but does not initiate, requests for 
+     <A HREF="#carpediem">opportunistic encryption</A> (OE). 
+     An opportunistic responder has enabled OE in its
+     <A HREF="#passive.OE">passive</A> form (pOE) only.
+     A web server or file server may be usefully set up as an opportunistic 
+      responder. 
+      <p>Configuring passive OE is described in our
+      <a href="policygroups.html#policygroups">policy groups</a> document.</p>
+    </dd>
+  <dt><a name="orange">Orange book</a></dt>
+    <dd>the most basic and best known of the US government's <a
+      href="#rainbow">Rainbow Book</a> series of computer security
+    standards.</dd>
+  <dt><a name="P">P</a></dt>
+  <dt><a name="P1363">P1363 standard</a></dt>
+    <dd>An <a href="#IEEE">IEEE</a> standard for public key cryptography. <a
+      href="http://grouper.ieee.org/groups/1363">Web page</a>.</dd>
+  <dt><a name="pOE">pOE</a></dt>
+    <dd>See <a href="#passive.OE">Passive opportunistic encryption</a>.</dd>
+  <dt><a name="passive">Passive attack</a></dt>
+    <dd>An attack in which the attacker only eavesdrops and attempts to
+      analyse intercepted messages, as opposed to an <a href="#active">active
+      attack</a> in which he diverts messages or generates his own.</dd>
+  <dt><a name="passive.OE">Passive opportunistic encryption (pOE)</a></dt>
+    <dd>A form of
+     <A HREF="#carpediem">opportunistic encryption</A> (OE) in which the
+     host will accept opportunistic connection requests, but will not 
+     initiate such requests. A host which runs OE in its passive form only 
+     is known as an <A HREF="#responder">opportunistic responder</A>.
+      <p>Configuring passive OE is described in our
+      <a href="policygroups.html#policygroups">policy groups</a> document.</p>
+    </dd>
+  <dt><a name="pathMTU">Path MTU discovery</a></dt>
+    <dd>The process of discovering the largest packet size which all links on
+      a path can handle without fragmentation -- that is, without any router
+      having to break the packet up into smaller pieces to match the <a
+      href="#MTU">MTU</a> of its outgoing link.
+      <p>This is done as follows:</p>
+      <ul>
+        <li>originator sends the largest packets allowed by <a
+          href="#MTU">MTU</a> of the first link, setting the DF
+          (<strong>d</strong>on't <strong>f</strong>ragment) bit in the
+          packet header</li>
+        <li>any router which cannot send the packet on (outgoing MTU is too
+          small for it, and DF prevents fragmenting it to match) sends back
+          an <a href="#ICMP.gloss">ICMP</a> packet reporting the problem</li>
+        <li>originator looks at ICMP message and tries a smaller size</li>
+        <li>eventually, you settle on a size that can pass all routers</li>
+        <li>thereafter, originator just sends that size and no-one has to
+          fragment</li>
+      </ul>
+      <p>Since this requires co-operation of many systems, and since the next
+      packet may travel a different path, this is one of the trickier areas
+      of IP programming. Bugs that have shown up over the years have
+      included:</p>
+      <ul>
+        <li>malformed ICMP messages</li>
+        <li>hosts that ignore or mishandle these ICMP messages</li>
+        <li>firewalls blocking the ICMP messages so host does not see
+        them</li>
+      </ul>
+      <p>Since IPsec adds a header, it increases packet size and may require
+      fragmentation even where incoming and outgoing MTU are equal.</p>
+    </dd>
+  <dt><a name="PFS">Perfect forward secrecy (PFS)</a></dt>
+    <dd>A property of systems such as <a href="#DH">Diffie-Hellman</a> key
+      exchange which use a long-term key (such as the shared secret in IKE)
+      and generate short-term keys as required. If an attacker who acquires
+      the long-term key <em>provably</em> can
+      <ul>
+        <li><em>neither</em> read previous messages which he may have
+        archived</li>
+        <li><em>nor</em> read future messages without performing additional
+          successful attacks</li>
+      </ul>
+      <p>then the system has PFS. The attacker needs the short-term keys in
+      order to read the trafiic and merely having the long-term key does not
+      allow him to infer those. Of course, it may allow him to conduct
+      another attack (such as <a href="#middle">man-in-the-middle</a>) which
+      gives him some short-term keys, but he does not automatically get them
+      just by acquiring the long-term key.</p>
+      <p>See also
+<a href="http://sandelman.ottawa.on.ca/ipsec/1996/08/msg00123.html">Phil 
+Karn's definition</a>.
+    </dd>
+  <dt>PFS</dt>
+    <dd>see Perfect Forward Secrecy</dd>
+  <dt><a name="PGP">PGP</a></dt>
+    <dd><b>P</b>retty <b>G</b>ood <b>P</b>rivacy, a personal encryption
+      system for email based on public key technology, written by Phil
+      Zimmerman.
+      <p>The 2.xx versions of PGP used the <a href="#RSA">RSA</a> public key
+      algorithm and used <a href="#IDEA">IDEA</a> as the symmetric cipher.
+      These versions are described in RFC 1991 and in <a
+      href="#PGP">Garfinkel's book</a>. Since version 5, the products from <a
+      href="#PGPI">PGP Inc</a>. have used <a href="#DH">Diffie-Hellman</a>
+      public key methods and <a href="#CAST128">CAST-128</a> symmetric
+      encryption. These can verify signatures from the 2.xx versions, but
+      cannot exchange encryted messages with them.</p>
+      <p>An <a href="#IETF">IETF</a> working group has issued RFC 2440 for an
+      "Open PGP" standard, similar to the 5.x versions. PGP Inc. staff were
+      among the authors. A free <a href="#GPG">Gnu Privacy Guard</a> based on
+      that standard is now available.</p>
+      <p>For more information on PGP, including how to obtain it, see our
+      cryptography <a href="web.html#tools">links</a>.</p>
+    </dd>
+  <dt><a name="PGPI">PGP Inc.</a></dt>
+    <dd>A company founded by Zimmerman, the author of <a href="#PGP">PGP</a>,
+      now a division of <a href="#NAI">NAI</a>. See the <a
+      href="http://www.pgp.com">corporate website</a>. Zimmerman left in
+      2001, and early in 2002 NAI announced that they would no longer sell
+      PGP..
+      <p>Versions 6.5 and later of the PGP product include PGPnet, an IPsec
+      client for Macintosh or for Windows 95/98/NT. See our <a
+      href="interop.html#pgpnet">interoperation documen</a>t.</p>
+    </dd>
+  <dt><a name="photuris">Photuris</a></dt>
+    <dd>Another key negotiation protocol, an alternative to <a
+      href="#IKE">IKE</a>, described in RFCs 2522 and 2523.</dd>
+  <dt><a name="PPP">PPP</a></dt>
+    <dd><b>P</b>oint-to-<b>P</b>oint <b>P</b>rotocol, originally a method of
+      connecting over modems or serial lines, but see also PPPoE.</dd>
+  <dt><a name="PPPoE">PPPoE</a></dt>
+    <dd><b>PPP</b> <b>o</b>ver <b>E</b>thernet, a somewhat odd protocol that
+      makes Ethernet look like a point-to-point serial link. It is widely
+      used for cable or ADSL Internet services, apparently mainly because it
+      lets the providers use access control and address assignmment
+      mechanisms developed for dialup networks. <a
+      href="http://www.roaringpenguin.com">Roaring Penguin</a> provide a
+      widely used Linux implementation.</dd>
+  <dt><a name="PPTP">PPTP</a></dt>
+    <dd><b>P</b>oint-to-<b>P</b>oint <b>T</b>unneling <b>P</b>rotocol, used
+      in some Microsoft VPN implementations. Papers discussing weaknesses in
+      it are on <a
+      href="http://www.counterpane.com/publish.html">counterpane.com</a>. It
+      is now largely obsolete, replaced by L2TP.</dd>
+  <dt><a name="PKI">PKI</a></dt>
+    <dd><b>P</b>ublic <b>K</b>ey <b>I</b>nfrastructure, the things an
+      organisation or community needs to set up in order to make <a
+      href="#public">public key</a> cryptographic technology a standard part
+      of their operating procedures.
+      <p>There are several PKI products on the market. Typically they use a
+      hierarchy of <a href="#CA">Certification Authorities (CAs)</a>. Often
+      they use <a href="#LDAP">LDAP</a> access to <a href="#X509">X.509</a>
+      directories to implement this.</p>
+      <p>See <a href="#web">Web of Trust</a> for a different sort of
+      infrastructure.</p>
+    </dd>
+  <dt><a name="PKIX">PKIX</a></dt>
+    <dd><b>PKI</b> e<b>X</b>change, an <a href="#IETF">IETF</a> standard that
+      allows <a href="#PKI">PKI</a>s to talk to each other.
+      <p>This is required, for example, when users of a corporate PKI need to
+      communicate with people at client, supplier or government
+      organisations, any of which may have a different PKI in place. I should
+      be able to talk to you securely whenever:</p>
+      <ul>
+        <li>your organisation and mine each have a PKI in place</li>
+        <li>you and I are each set up to use those PKIs</li>
+        <li>the two PKIs speak PKIX</li>
+        <li>the configuration allows the conversation</li>
+      </ul>
+      <p>At time of writing (March 1999), this is not yet widely implemented
+      but is under quite active development by several groups.</p>
+    </dd>
+  <dt><a name="plaintext">Plaintext</a></dt>
+    <dd>The unencrypted input to a cipher, as opposed to the encrypted <a
+      href="#ciphertext">ciphertext</a> output.</dd>
+  <dt><a name="Pluto">Pluto</a></dt>
+    <dd>The <a href="#FreeSWAN">Linux FreeS/WAN</a> daemon which handles key
+      exchange via the <a href="#IKE">IKE</a> protocol, connection
+      negotiation, and other higher-level tasks. Pluto calls the <a
+      href="#KLIPS">KLIPS</a> kernel code as required. For details, see the
+      manual page ipsec_pluto(8).</dd>
+  <dt><a name="public">Public Key Cryptography</a></dt>
+    <dd>In public key cryptography, keys are created in matched pairs.
+      Encrypt with one half of a pair and only the matching other half can
+      decrypt it. This contrasts with <a href="#symmetric">symmetric or
+      secret key cryptography</a> in which a single key known to both parties
+      is used for both encryption and decryption.
+      <p>One half of each pair, called the public key, is made public. The
+      other half, called the private key, is kept secret. Messages can then
+      be sent by anyone who knows the public key to the holder of the private
+      key. Encrypt with the public key and you know that only someone with
+      the matching private key can decrypt.</p>
+      <p>Public key techniques can be used to create <a
+      href="#signature">digital signatures</a> and to deal with key
+      management issues, perhaps the hardest part of effective deployment of
+      <a href="#symmetric"> symmetric ciphers</a>. The resulting <a
+      href="#hybrid">hybrid cryptosystems</a> use public key methods to
+      manage keys for symmetric ciphers.</p>
+      <p>Many organisations are currently creating <a href="#PKI">PKIs,
+      public key infrastructures</a> to make these benefits widely
+      available.</p>
+    </dd>
+  <dt>Public Key Infrastructure</dt>
+    <dd>see <a href="#PKI">PKI</a></dd>
+  <dt><a name="Q">Q</a></dt>
+  <dt><a name="R">R</a></dt>
+  <dt><a name="rainbow">Rainbow books</a></dt>
+    <dd>A set of US government standards for evaluation of "trusted computer
+      systems", of which the best known was the <a href="#orange">Orange
+      Book</a>. One fairly often hears references to "C2 security" or a
+      product "evaluated at B1". The Rainbow books define the standards
+      referred to in those comments.
+      <p>See this <a href="http://www.fas.org/irp/nsa/rainbow.htm">reference
+      page</a>.</p>
+      <p>The Rainbow books are now mainly obsolete, replaced by the
+      international <a href="#cc">Common Criteria</a> standards.</p>
+    </dd>
+  <dt><a name="random">Random</a></dt>
+    <dd>A remarkably tricky term, far too much so for me to attempt a
+      definition here. Quite a few cryptosystems have been broken via attacks
+      on weak random number generators, even when the rest of the system was
+      sound.
+      <p>See <a
+      href="http://nis.nsf.net/internet/documents/rfc/rfc1750.txt">RFC
+      1750</a> for the theory.</p>
+      <p>See the manual pages for <a
+      href="manpage.d/ipsec_ranbits.8.html">ipsec_ranbits(8)</a> and
+      ipsec_prng(3) for more on FreeS/WAN's use of randomness. Both depend on
+      the random(4) device driver..</p>
+      <p>A couple of years ago, there was extensive mailing list discussion
+      (archived <a
+      href="http://www.openpgp.net/random/index.html">here</a>)of Linux
+      /dev/random and FreeS/WAN.  Since then, the design of the random(4)
+      driver has changed considerably. Linux 2.4 kernels have the new
+      driver..</p>
+    </dd>
+  <dt>Raptor</dt>
+    <dd>A firewall product for Windows NT offerring IPsec-based VPN services.
+      Linux FreeS/WAN interoperates with Raptor; see our <a
+      href="interop.html#Raptor">interop</a> document for details. Raptor
+      have recently merged with Axent.</dd>
+  <dt><a name="RC4">RC4</a></dt>
+    <dd><b>R</b>ivest <b>C</b>ipher four, designed by Ron Rivest of <a
+      href="#RSAco">RSA</a> and widely used. Believed highly secure with
+      adequate key length, but often implemented with inadequate key length
+      to comply with export restrictions.</dd>
+  <dt><a name="RC6">RC6</a></dt>
+    <dd><b>R</b>ivest <b>C</b>ipher six, <a href="#RSAco">RSA</a>'s <a
+      href="#AES">AES</a> candidate cipher.</dd>
+  <dt><a name="replay">Replay attack</a></dt>
+    <dd>An attack in which the attacker records data and later replays it in
+      an attempt to deceive the recipient.</dd>
+  <dt><a name="reverse">Reverse map</a></dt>
+    <dd>In <a href="#DNS">DNS</a>, a table where IP addresses can be used as
+      the key for lookups which return a system name and/or other
+    information.</dd>
+  <dt>RFC</dt>
+    <dd><b>R</b>equest <b>F</b>or <b>C</b>omments, an Internet document. Some
+      RFCs are just informative. Others are standards.
+      <p>Our list of <a href="#IPSEC">IPsec</a> and other security-related
+      RFCs is <a href="rfc.html#RFC">here</a>, along with information on
+      methods of obtaining them.</p>
+    </dd>
+  <dt><a name="rijndael">Rijndael</a></dt>
+    <dd>a <a href="#block">block cipher</a> designed by two Belgian
+      cryptographers, winner of the US government's <a href="#AES">AES</a>
+      contest to pick a replacement for <a href="#DES">DES</a>. See the <a
+      href="http://www.esat.kuleuven.ac.be/~rijmen/rijndael">Rijndael home
+      page</a>.</dd>
+  <dt><a name="RIPEMD">RIPEMD</a></dt>
+    <dd>A <a href="#digest">message digest</a> algorithm. The current version
+      is RIPEMD-160 which gives a 160-bit hash.</dd>
+  <dt><a name="rootCA">Root CA</a></dt>
+    <dd>The top level <a href="#CA">Certification Authority</a> in a hierachy
+      of such authorities.</dd>
+  <dt><a name="routable">Routable IP address</a></dt>
+    <dd>Most IP addresses can be used as "to" and "from" addresses in packet
+      headers. These are the routable addresses; we expect routing to be
+      possible for them. If we send a packet to one of them, we expect (in
+      most cases; there are various complications) that it will be delivered
+      if the address is in use and will cause an <a
+      href="#ICMP.gloss">ICMP</a> error packet to come back to us if not.
+      <p>There are also several classes of <a
+      href="#non-routable">non-routable</a> IP addresses.</p>
+    </dd>
+  <dt><a name="RSA">RSA algorithm</a></dt>
+    <dd><b>R</b>ivest <b>S</b>hamir <b>A</b>dleman <a href="#public">public
+      key</a> algorithm, named for its three inventors. It is widely used and
+      likely to become moreso since it became free of patent encumbrances in
+      September 2000.
+      <p>RSA can be used to provide either <a
+      href="#encryption">encryption</a> or <a href="#signature">digital
+      signatures</a>. In IPsec, it is used only for signatures. These provide
+      gateway-to-gateway <a href="#authentication">authentication</a> for <a
+      href="#IKE">IKE </a>negotiations.</p>
+      <p>For a full explanation of the algorithm, consult one of the standard
+      references such as <a href="biblio.html#schneier">Applied
+      Cryptography</a>. A simple explanation is:</p>
+      <p>The great 17th century French mathematician <a
+      href="http://www-groups.dcs.st-andrews.ac.uk/~history/Mathematicians/Fermat.html">Fermat</a>
+      proved that,</p>
+      <p>for any prime p and number x, 0 &lt;= x &lt; p:</p>
+      <pre>        x^p == x         modulo p
+        x^(p-1) == 1     modulo p, non-zero x
+      </pre>
+      <p>From this it follows that if we have a pair of primes p, q and two
+      numbers e, d such that:</p>
+      <pre>        ed == 1          modulo lcm( p-1, q-1)
+      </pre>
+      where lcm() is least common multiple, then<br>
+      for all x, 0 &lt;= x &lt; pq:
+      <pre>      x^ed == x           modulo pq
+      </pre>
+      <p>So we construct such as set of numbers p, q, e, d and publish the
+      product N=pq and e as the public key. Using c for <a
+      href="#ciphertext">ciphertext</a> and i for the input <a
+      href="#plaintext">plaintext</a>, encryption is then:</p>
+      <pre>        c = i^e           modulo N
+      </pre>
+      <p>An attacker cannot deduce i from the cyphertext c, short of either
+      factoring N or solving the <a href="#dlog">discrete logarithm</a>
+      problem for this field. If p, q are large primes (hundreds or thousands
+      of bits) no efficient solution to either problem is known.</p>
+      <p>The receiver, knowing the private key (N and d), can readily recover
+      the plaintext p since:</p>
+      <pre>        c^d == (i^e)^d    modulo N
+            == i^ed       modulo N
+            == i          modulo N
+      </pre>
+      <p>This gives an effective public key technique, with only a couple of
+      problems. It uses a good deal of computer time, since calculations with
+      large integers are not cheap, and there is no proof it is necessarily
+      secure since no-one has proven either factoring or discrete log cannot
+      be done efficiently. Quite a few good mathematicians have tried both
+      problems, and no-one has announced success, but there is no proof they
+      are insoluble.</p>
+    </dd>
+  <dt><a name="RSAco">RSA Data Security</a></dt>
+    <dd>A company founded by the inventors of the <a href="#RSA">RSA</a>
+      public key algorithm.</dd>
+  <dt><a name="S">S</a></dt>
+  <dt><a name="SA">SA</a></dt>
+    <dd><b>S</b>ecurity <b>A</b>ssociation, the channel negotiated by the
+      higher levels of an <a href="#IPSEC">IPsec</a> implementation (<a
+      href="#IKE">IKE</a>) and used by the lower (<a href="#ESP">ESP</a> and
+      <a href="#AH">AH</a>). SAs are unidirectional; you need a pair of them
+      for two-way communication.
+      <p>An SA is defined by three things -- the destination, the protocol
+      (<a href="#AH">AH</a> or<a href="#ESP">ESP</a>) and the <a
+      href="SPI">SPI</a>, security parameters index. It is used as an index
+      to look up other things such as session keys and intialisation
+      vectors.</p>
+      <p>For more detail, see our section on <a href="ipsec.html">IPsec</a>
+      and/or RFC 2401.</p>
+    </dd>
+  <dt><a name="SElinux">SE Linux</a></dt>
+    <dd><strong>S</strong>ecurity <strong>E</strong>nhanced Linux, an <a
+      href="#NSA">NSA</a>-funded project to add <a
+      href="#mandatory">mandatory access control</a> to Linux. See the <a
+      href="http://www.nsa.gov/selinux">project home page</a>.
+      <p>According to their web pages, this work will include extending
+      mandatory access controls to IPsec tunnels.</p>
+      <p>Recent versions of SE Linux code use the <a href="#LSM">Linux
+      Security Module</a> interface.</p>
+    </dd>
+  <dt><a name="SDNS">Secure DNS</a></dt>
+    <dd>A version of the <a href="#DNS">DNS or Domain Name Service</a>
+      enhanced with authentication services. This is being designed by the <a
+      href="#IETF">IETF</a> DNS security <a
+      href="http://www.ietf.org/ids.by.wg/dnssec.html">working group</a>.
+      Check the <a href="http://www.isc.org/bind.html">Internet Software
+      Consortium</a> for information on implementation progress and for the
+      latest version of <a href="#BIND">BIND</a>. Another site has <a
+      href="http://www.toad.com/~dnssec">more information</a>.
+      <p><a href="#IPSEC">IPsec</a> can use this plus <a
+      href="#DH">Diffie-Hellman key exchange</a> to bootstrap itself. This
+      allows <a href="#carpediem">opportunistic encryption</a>. Any pair of
+      machines which can authenticate each other via DNS can communicate
+      securely, without either a pre-existing shared secret or a shared <a
+      href="#PKI">PKI</a>.</p>
+    </dd>
+  <dt>Secret key cryptography</dt>
+    <dd>See <a href="#symmetric">symmetric cryptography</a></dd>
+  <dt>Security Association</dt>
+    <dd>see <a href="#SA">SA</a></dd>
+  <dt>Security Enhanced Linux</dt>
+    <dd>see <a href="#SElinux">SE Linux</a></dd>
+  <dt><a name="sequence">Sequence number</a></dt>
+    <dd>A number added to a packet or message which indicates its position in
+      a sequence of packets or messages. This provides some security against
+      <a href="#replay">replay attacks</a>.
+      <p>For <a href="#auto">automatic keying</a> mode, the <a
+      href="#IPSEC">IPsec</a> RFCs require that the sender generate sequence
+      numbers for each packet, but leave it optional whether the receiver
+      does anything with them.</p>
+    </dd>
+  <dt><a name="SHA">SHA</a></dt>
+  <dt>SHA-1</dt>
+    <dd><b>S</b>ecure <b>H</b>ash <b>A</b>lgorithm, a <a
+      href="#digest">message digest algorithm</a> developed by the <a
+      href="#NSA">NSA</a> for use in the Digital Signature standard, <a
+      href="#FIPS">FIPS</a> number 186 from <a href="#NIST">NIST</a>. SHA is
+      an improved variant of <a href="#MD4">MD4</a> producing a 160-bit hash.
+      <p>SHA is one of two message digest algorithms available in IPsec. The
+      other is <a href="#MD5">MD5</a>. Some people do not trust SHA because
+      it was developed by the <a href="#NSA">NSA</a>. There is, as far as we
+      know, no cryptographic evidence that SHA is untrustworthy, but this
+      does not prevent that view from being strongly held.</p>
+      <p>The NSA made one small change after the release of the original SHA.
+      They did not give reasons. Iit may be a defense against some attack
+      they found and do not wish to disclose.  Technically the modified
+      algorithm should be called SHA-1, but since it has replaced the
+      original algorithm in nearly all applications, it is generally just
+      referred to as SHA..</p>
+    </dd>
+  <dt><a name="SHA-256">SHA-256</a></dt>
+  <dt>SHA-384</dt>
+  <dt>SHA-512</dt>
+    <dd>Newer variants of SHA designed to match the strength of the 128, 192
+      and 256-bit keys of <a href="#AES">AES</a>. The work to break an
+      encryption algorithm's strength by <a href="#brute">brute force</a> is
+      2 
+      <math xmlns="http://www.w3.org/1998/Math/MathML">
+        <msup>
+          <mi>keylength</mi>
+        </msup>
+      </math>
+       operations but a <a href="birthday">birthday attack </a>on a hash
+      needs only 2 
+      <math xmlns="http://www.w3.org/1998/Math/MathML">
+        <msup>
+          <mrow>
+            <mi>hashlength</mi>
+            <mo>/</mo>
+            <mn>2</mn>
+          </mrow>
+        </msup>
+      </math>
+       , so as a general rule you need a hash twice the size of the key to
+      get similar strength. SHA-256, SHA-384 and SHA-512 are designed to
+      match the 128, 192 and 256-bit key sizes of AES, respectively.</dd>
+  <dt><a name="SIGINT">Signals intelligence (SIGINT)</a></dt>
+    <dd>Activities of government agencies from various nations aimed at
+      protecting their own communications and reading those of others.
+      Cryptography, cryptanalysis, wiretapping, interception and monitoring
+      of various sorts of signals. The players include the American <a
+      href="#NSA">NSA</a>, British <a href="#GCHQ">GCHQ</a> and Canadian <a
+      href="#CSE">CSE</a>.</dd>
+  <dt><a name="SKIP">SKIP</a></dt>
+    <dd><b>S</b>imple <b>K</b>ey management for <b>I</b>nternet
+      <b>P</b>rotocols, an alternative to <a href="#IKE">IKE</a> developed by
+      Sun and being marketed by their <a
+      href="http://skip.incog.com">Internet Commerce Group</a>.</dd>
+  <dt><a name="snake">Snake oil</a></dt>
+    <dd>Bogus cryptography. See the <a
+      href="http://www.interhack.net/people/cmcurtin/snake-oil-faq.html">
+      Snake Oil FAQ</a> or <a
+      href="http://www.counterpane.com/crypto-gram-9902.html#snakeoil">this
+      paper</a> by Schneier.</dd>
+  <dt><a name="SPI">SPI</a></dt>
+    <dd><b>S</b>ecurity <b>P</b>arameter <b>I</b>ndex, an index used within
+      <a href="#IPSEC">IPsec</a> to keep connections distinct. A <a
+      href="#SA">Security Association (SA)</a> is defined by destination,
+      protocol and SPI. Without the SPI, two connections to the same gateway
+      using the same protocol could not be distinguished.
+      <p>For more detail, see our <a href="ipsec.html">IPsec</a> section
+      and/or RFC 2401.</p>
+    </dd>
+  <dt><a name="SSH">SSH</a></dt>
+    <dd><b>S</b>ecure <b>SH</b>ell, an encrypting replacement for the
+      insecure Berkeley commands whose names begin with "r" for "remote":
+      rsh, rlogin, etc.
+      <p>For more information on SSH, including how to obtain it, see our
+      cryptography <a href="web.html#tools">links</a>.</p>
+    </dd>
+  <dt><a name="SSHco">SSH Communications Security</a></dt>
+    <dd>A company founded by the authors of <a href="#SSH">SSH</a>. Offices
+      are in <a href="http://www.ssh.fi">Finland</a> and <a
+      href="http://www.ipsec.com">California</a>. They have a toolkit for
+      developers of IPsec applications.</dd>
+  <dt><a name="SSL">SSL</a></dt>
+    <dd><a href="http://home.netscape.com/eng/ssl3">Secure Sockets Layer</a>,
+      a set of encryption and authentication services for web browsers,
+      developed by Netscape. Widely used in Internet commerce. Also known as
+      <a href="#TLS">TLS</a>.</dd>
+  <dt>SSLeay</dt>
+    <dd>A free implementation of <a href="#SSL">SSL</a> by Eric Young (eay)
+      and others. Developed in Australia; not subject to US export
+    controls.</dd>
+  <dt><a name="static">static IP address</a></dt>
+    <dd>an IP adddress which is pre-set on the machine itself, as opposed to
+      a <a href="#dynamic">dynamic address</a> which is assigned by a <a
+      href="#DHCP">DHCP</a> server or obtained as part of the process of
+      establishing a <a href="#PPP">PPP</a> or <a href="#PPPoE">PPPoE</a>
+      connection</dd>
+  <dt><a name="stream">Stream cipher</a></dt>
+    <dd>A <a href="#symmetric">symmetric cipher</a> which produces a stream
+      of output which can be combined (often using XOR or bytewise addition)
+      with the plaintext to produce ciphertext. Contrasts with <a
+      href="#block">block cipher</a>.
+      <p><a href="#IPSEC">IPsec</a> does not use stream ciphers. Their main
+      application is link-level encryption, for example of voice, video or
+      data streams on a wire or a radio signal.</p>
+    </dd>
+  <dt><a name="subnet">subnet</a></dt>
+    <dd>A group of IP addresses which are logically one network, typically
+      (but not always) assigned to a group of physically connected machines.
+      The range of addresses in a subnet is described using a subnet mask.
+      See next entry.</dd>
+  <dt>subnet mask</dt>
+    <dd>A method of indicating the addresses included in a subnet. Here are
+      two equivalent examples:
+      <ul>
+        <li>101.101.101.0/24</li>
+        <li>101.101.101.0 with mask 255.255.255.0</li>
+      </ul>
+      <p>The '24' is shorthand for a mask with the top 24 bits one and the
+      rest zero. This is exactly the same as 255.255.255.0 which has three
+      all-ones bytes and one all-zeros byte.</p>
+      <p>These indicate that, for this range of addresses, the top 24 bits
+      are to be treated as naming a network (often referred to as "the
+      101.101.101.0/24 subnet") while most combinations of the low 8 bits can
+      be used to designate machines on that network. Two addresses are
+      reserved; 101.101.101.0 refers to the subnet rather than a specific
+      machine while 101.101.101.255 is a broadcast address. 1 to 254 are
+      available for machines.</p>
+      <p>It is common to find subnets arranged in a hierarchy. For example, a
+      large company might have a /16 subnet and allocate /24 subnets within
+      that to departments. An ISP might have a large subnet and allocate /26
+      subnets (64 addresses, 62 usable) to business customers and /29 subnets
+      (8 addresses, 6 usable) to residential clients.</p>
+    </dd>
+  <dt><a name="SWAN">S/WAN</a></dt>
+    <dd>Secure Wide Area Network, a project involving <a href="#RSAco">RSA
+      Data Security</a> and a number of other companies. The goal was to
+      ensure that all their <a href="#IPSEC">IPsec</a> implementations would
+      interoperate so that their customers can communicate with each other
+      securely.</dd>
+  <dt><a name="symmetric">Symmetric cryptography</a></dt>
+    <dd>Symmetric cryptography, also referred to as conventional or secret
+      key cryptography, relies on a <em>shared secret key</em>, identical for
+      sender and receiver. Sender encrypts with that key, receiver decrypts
+      with it. The idea is that an eavesdropper without the key be unable to
+      read the messages. There are two main types of symmetric cipher, <a
+      href="#block">block ciphers</a> and <a href="#stream">stream
+      ciphers</a>.
+      <p>Symmetric cryptography contrasts with <a href="#public">public
+      key</a> or asymmetric systems where the two players use different
+      keys.</p>
+      <p>The great difficulty in symmetric cryptography is, of course, key
+      management. Sender and receiver <em>must</em> have identical keys and
+      those keys <em>must</em> be kept secret from everyone else. Not too
+      much of a problem if only two people are involved and they can
+      conveniently meet privately or employ a trusted courier. Quite a
+      problem, though, in other circumstances.</p>
+      <p>It gets much worse if there are many people. An application might be
+      written to use only one key for communication among 100 people, for
+      example, but there would be serious problems. Do you actually trust all
+      of them that much? Do they trust each other that much? Should they?
+      What is at risk if that key is compromised? How are you  going to
+      distribute that key to everyone without risking its secrecy? What do
+      you do when one of them leaves the company? Will you even know?</p>
+      <p>On the other hand, if you need unique keys for every possible
+      connection between a group of 100, then each user must have 99 keys.
+      You need either 99*100/2 = 4950 <em>secure</em> key exchanges between
+      users or a central authority that <em>securely</em> distributes 100 key
+      packets, each with a different set of 99 keys.</p>
+      <p>Either of these is possible, though tricky, for 100 users. Either
+      becomes an administrative nightmare for larger numbers. Moreover, keys
+      <em>must</em> be changed regularly, so the problem of key distribution
+      comes up again and again. If you use the same key for many messages
+      then an attacker has more text to work with in an attempt to crack that
+      key. Moreover, one successful crack will give him or her the text of
+      all those messages.</p>
+      <p>In short, the <em>hardest part of conventional cryptography is key
+      management</em>. Today the standard solution is to build a <a
+      href="#hybrid">hybrid system</a> using <a href="#public">public key</a>
+      techniques to manage keys.</p>
+    </dd>
+  <dt><a name="T">T</a></dt>
+  <dt><a name="TIS">TIS</a></dt>
+    <dd>Trusted Information Systems, a firewall vendor now part of <a
+      href="#NAI">NAI</a>. Their Gauntlet product offers IPsec VPN services.
+      TIS implemented the first version of <a href="#SDNS">Secure DNS</a> on
+      a <a href="#DARPA">DARPA</a> contract.</dd>
+  <dt><a name="TLS">TLS</a></dt>
+    <dd><b>T</b>ransport <b>L</b>ayer <b>S</b>ecurity, a newer name for <a
+      href="#SSL">SSL</a>.</dd>
+  <dt><a name="TOS">TOS field</a></dt>
+    <dd>The <strong>T</strong>ype <strong>O</strong>f
+      <strong>S</strong>ervice field in an IP header, used to control
+      qualkity of service routing.</dd>
+  <dt><a name="traffic">Traffic analysis</a></dt>
+    <dd>Deducing useful intelligence from patterns of message traffic,
+      without breaking codes or reading the messages. In one case during
+      World War II, the British guessed an attack was coming because all
+      German radio traffic stopped. The "radio silence" order, intended to
+      preserve security, actually gave the game away.
+      <p>In an industrial espionage situation, one might deduce something
+      interesting just by knowing that company A and company B were talking,
+      especially if one were able to tell which departments were involved, or
+      if one already knew that A was looking for acquisitions and B was
+      seeking funds for expansion.</p>
+      <p>In general, traffic analysis by itself is not very useful. However,
+      in the context of a larger intelligence effort where quite a bit is
+      already known, it can be very useful. When you are solving a complex
+      puzzle, every little bit helps.</p>
+      <p><a href="#IPSEC">IPsec</a> itself does not defend against traffic
+      analysis, but carefully thought out systems using IPsec can provide at
+      least partial protection. In particular, one might want to encrypt more
+      traffic than was strictly necessary, route things in odd ways, or even
+      encrypt dummy packets, to confuse the analyst. We discuss this <a
+      href="ipsec.html#traffic.resist">here</a>.</p>
+    </dd>
+  <dt><a name="transport">Transport mode</a></dt>
+    <dd>An IPsec application in which the IPsec gateway is the destination of
+      the protected packets, a machine acts as its own gateway. Contrast with
+      <a href="#tunnel">tunnel mode</a>.</dd>
+  <dt>Triple DES</dt>
+    <dd>see <a href="#3DES">3DES</a></dd>
+  <dt><a name="TTL">TTL</a></dt>
+    <dd><strong>T</strong>ime <strong>T</strong>o <strong>L</strong>ive, used
+      to control <a href="#DNS">DNS</a> caching. Servers discard cached
+      records whose TTL expires</dd>
+  <dt><a name="tunnel">Tunnel mode</a></dt>
+    <dd>An IPsec application in which an IPsec gateway provides protection
+      for packets to and from other systems. Contrast with <a
+      href="#transport">transport mode</a>.</dd>
+  <dt><a name="2key">Two-key Triple DES</a></dt>
+    <dd>A variant of <a href="#3DES">triple DES or 3DES</a> in which only two
+      keys are used. As in the three-key version, the order of operations is
+      <a href="#EDE">EDE</a> or encrypt-decrypt-encrypt, but in the two-key
+      variant the first and third keys are the same.
+      <p>3DES with three keys has 3*56 = 168 bits of key but has only 112-bit
+      strength against a <a href="#meet">meet-in-the-middle</a> attack, so it
+      is possible that the two key version is just as strong. Last I looked,
+      this was an open question in the research literature.</p>
+      <p>RFC 2451 defines triple DES for <a href="#IPSEC">IPsec</a> as the
+      three-key variant. The two-key variant should not be used and is not
+      implemented directly in <a href="#FreeSWAN">Linux FreeS/WAN</a>. It
+      cannot be used in automatically keyed mode without major fiddles in the
+      source code. For manually keyed connections, you could make Linux
+      FreeS/WAN talk to a two-key implementation by setting two keys the same
+      in /etc/ipsec.conf.</p>
+    </dd>
+  <dt><a name="U">U</a></dt>
+  <dt><a name="V">V</a></dt>
+  <dt><a name="virtual">Virtual Interface</a></dt>
+    <dd>A <a href="#Linux">Linux</a> feature which allows one physical
+      network interface to have two or more IP addresses. See the <cite>Linux
+      Network Administrator's Guide</cite> in <a
+      href="biblio.html#kirch">book form</a> or <a
+      href="http://metalab.unc.edu/LDP/LDP/nag/node1.html">on the web</a> for
+      details.</dd>
+  <dt>Virtual Private Network</dt>
+    <dd>see <a href="#VPN">VPN</a></dd>
+  <dt><a name="VPN">VPN</a></dt>
+    <dd><b>V</b>irtual <b>P</b>rivate <b>N</b>etwork, a network which can
+      safely be used as if it were private, even though some of its
+      communication uses insecure connections. All traffic on those
+      connections is encrypted.
+      <p><a href="#IPSEC">IPsec</a> is not the only technique available for
+      building VPNs, but it is the only method defined by <a
+      href="#RFC">RFCs</a> and supported by many vendors. VPNs are by no
+      means the only thing you can do with IPsec, but they may be the most
+      important application for many users.</p>
+    </dd>
+  <dt><a name="VPNC">VPNC</a></dt>
+    <dd><a href="http://www.vpnc.org">Virtual Private Network Consortium</a>,
+      an association of vendors of VPN products.</dd>
+  <dt><a name="W">W</a></dt>
+  <dt><a name="Wassenaar.gloss">Wassenaar Arrangement</a></dt>
+    <dd>An international agreement restricting export of munitions and other
+      tools of war. Unfortunately, cryptographic software is also restricted
+      under the current version of the agreement. <a
+      href="politics.html#Wassenaar">Discussion</a>.</dd>
+  <dt><a name="web">Web of Trust</a></dt>
+    <dd><a href="#PGP">PGP</a>'s method of certifying keys. Any user can sign
+      a key; you decide which signatures or combinations of signatures to
+      accept as certification. This contrasts with the hierarchy of <a
+      href="#CA">CAs (Certification Authorities)</a> used in many <a
+      href="#PKI">PKIs (Public Key Infrastructures)</a>.
+      <p>See <a href="#GTR">Global Trust Register</a> for an interesting
+      addition to the web of trust.</p>
+    </dd>
+  <dt><a name="WEP">WEP (Wired Equivalent Privacy)</a></dt>
+    <dd>The cryptographic part of the <a href="#IEEE">IEEE</a> standard for
+      wireless LANs. As the name suggests, this is designed to be only as
+      secure as a normal wired ethernet. Anyone with a network conection can
+      tap it. Its advocates would claim this is good design, refusing to
+      build in complex features beyond the actual requirements.
+      <p>Critics refer to WEP as "Wire<em>tap</em> Equivalent Privacy", and
+      consider it a horribly flawed design based on bogus "requirements". You
+      do not control radio waves as you might control your wires, so the
+      metaphor in the rationale is utterly inapplicable. A security policy
+      that chooses not to invest resources in protecting against certain
+      attacks which can only be conducted by people physically plugged into
+      your LAN may or may not be reasonable. The same policy is completely
+      unreasonable when someone can "plug in" from a laptop half a block
+      away..</p>
+      <p>There has been considerable analysis indicating that WEP is
+      seriously flawed. A FAQ on attacks against WEP is available. Part of it
+      reads:</p>
+
+      <blockquote>
+        ... attacks are practical to mount using only inexpensive
+        off-the-shelf equipment. We recommend that anyone using an 802.11
+        wireless network not rely on WEP for security, and employ other
+        security measures to protect their wireless network. Note that our
+        attacks apply to both 40-bit and the so-called 128-bit versions of
+        WEP equally well.</blockquote>
+      <p>WEP appears to be yet another instance of governments, and
+      unfortunately some vendors and standards bodies, deliberately promoting
+      hopelessly flawed "security" products, apparently mainly for the
+      benefit of eavesdropping agencies. See this <a
+      href="politics.html#weak">discussion</a>.</p>
+    </dd>
+  <dt><a name="X">X</a></dt>
+  <dt><a name="X509">X.509</a></dt>
+    <dd>A standard from the <a href="http://www.itu.int">ITU (International
+      Telecommunication Union)</a>, for hierarchical directories with
+      authentication services, used in many <a href="#PKI">PKI</a>
+      implementations.
+      <p>Use of X.509 services, via the <a href="#LDAP">LDAP protocol</a>,
+      for certification of keys is allowed but not required by the <a
+      href="#IPSEC">IPsec</a> RFCs. It is not yet implemented in <a
+      href="#FreeSWAN">Linux FreeS/WAN</a>.</p>
+    </dd>
+  <dt>Xedia</dt>
+    <dd>A vendor of router and Internet access products, now part of Lucent.
+      Their QVPN products interoperate with Linux FreeS/WAN; see our <a
+      href="interop.html#Xedia">interop document</a>.</dd>
+  <dt><a name="Y">Y</a></dt>
+  <dt><a name="Z">Z</a></dt>
+</dl>
+</body>
+</html>
diff --git a/doc/src/index.html b/doc/src/index.html
new file mode 100644
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@@ -0,0 +1,55 @@
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>FreeS/WAN index</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, encryption, cryptography, FreeS/WAN, FreeSWAN">
+  <!--
+
+  Written by Claudia Schmeing for the Linux FreeS/WAN project
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: index.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+
+<body>
+<h1>FreeS/WAN documentation</h1>
+
+<ul>
+  <li><a href="intro.html">Introduction</a></li>
+  <li><a href="upgrading.html">Upgrading to 2.x</a></li>
+</ul>
+
+<ul> 
+  <li><a href="quickstart.html">Quickstart guide to Opportunistic Encryption</a></li>
+  <li><a href="install.html">Installing</a></li>
+  <li><a href="config.html">Configuring</a></li>
+  <li><a href="policygroups.html">Policy Groups</a> 
+                   </li>
+  <li><a href="interop.html">Interoperating</a> 
+<FONT COLOR="#FF0000">New and improved!</FONT></li>
+  <li><a href="faq.html">FAQ</a></li>
+  <li><a href="trouble.html">Troubleshooting and problem reporting</a></li>
+</ul>
+
+<ul>
+  <li><a href="toc.html">Full table of contents, with much more</a></li>
+  <li><a href="HowTo.html">All our docs as one big file</a></li>
+</ul>  
+
+<p>For technical support and other questions, use our <a
+href="mail.html">mailing lists</a>.</p>
+
+<pre>        This index last changed:    $Date: 2004/03/15 20:35:24 $</pre>
+
+</body>
+</html>
diff --git a/doc/src/initiatorstate.txt b/doc/src/initiatorstate.txt
new file mode 100644
index 000000000..315f6da4c
--- /dev/null
+++ b/doc/src/initiatorstate.txt
@@ -0,0 +1,66 @@
+
+                       |
+	               | PF_ACQUIRE
+		       |     
+                       V
+                .---------------.       
+                |  non-existant |
+                |  connection   |
+                `---------------'
+                 |      |      |
+          send   ,      |      \
+expired   pass  /       |       \ send
+conn.     msg  /        |        \ deny
+  ^           /         |         \ msg
+  |          V          | do       \ 		 
+.---------------.       | DNS       \   .---------------.  
+|  clear-text   |	| lookup     `->|     deny      |---> expired
+|  connection   |	| for 	        |  connection   |     connection
+`---------------'	| destination   `---------------'
+   ^ ^                  |                   ^
+   | | no record        |                   |
+   | | OE-permissive    V                   | no record
+   | |            .---------------.         | OE-paranoid
+   | `------------|  potential OE |---------'
+   |              |  connection   |         ^
+   |              `---------------'         |
+   |                    |                   |
+   |                    | got TXT record    | DNSSEC failure
+   |                    | reply             |
+   |                    V                   | wrong 
+   |              .---------------.         | failure
+   |              |  authenticate |---------'
+   |              | & parse TXT RR|         ^
+   | repeated     `---------------'         |
+   | ICMP               |                   |
+   | failures           | initiate IKE to   |                         
+   | (short-timeout)    | responder         |                         
+   |                    V                   |                          
+   | phase-2      .---------------.         | failure                       
+   | failure      |   pending     |---------'                          
+   | (normal      |     OE        |         ^                          
+   |  timeout)    |               |invalid  | phase-2 failure (short-timeout)
+   |              |               |<--.SPI  | ICMP failures (normal timeout)
+   |              |               |   |     |                          
+   |              | +=======+     |---'     |                          
+   |              | |  IKE  |     |   ^     |                          
+   `--------------| | states|---------------'                          
+                  | +=======+     |   |                                
+                  `---------------'   |                                
+                        |             | invalid SPI                    
+                        |             |                                
+	                V             | rekey time                     
+                  .--------------.    |                                
+                  |   keyed      |<---|-------------------------------.
+                  |  connection  |----'                               |
+                  `--------------'                                    |
+                        |                                             |
+                        |                                             |
+                        V                                             |
+                  .--------------.     connection still active        |
+  clear-text----->|   expired    |------------------------------------'
+        deny----->|  connection  |
+                  `--------------'
+
+
+$Id: initiatorstate.txt,v 1.1 2004/03/15 20:35:24 as Exp $
diff --git a/doc/src/install.html b/doc/src/install.html
new file mode 100644
index 000000000..09d7c5a67
--- /dev/null
+++ b/doc/src/install.html
@@ -0,0 +1,378 @@
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>Installing FreeS/WAN</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, FreeSWAN, installation, quickstart">
+  <!--
+
+  Written by Claudia Schmeing for the Linux FreeS/WAN project
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: install.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+<BODY>
+<H1><A name="install">Installing FreeS/WAN</A></H1>
+
+<P>This document will teach you how to install Linux FreeS/WAN. 
+If your distribution comes with Linux FreeS/WAN, we offer
+ tips to get you started.</P>
+
+<H2>Requirements</H2>
+
+<P>To install FreeS/WAN you must:</P>
+<UL>
+<LI>be running Linux with the 2.4 or 2.2 kernel series. See 
+this <A HREF="http://www.freeswan.ca/download.php#contact">kernel 
+compatibility table</A>.<BR>We also have experimental support for 
+2.6 kernels. Here are two basic approaches:
+<UL><LI>
+install FreeS/WAN, including its <A HREF="ipsec.html#parts">KLIPS</A>
+kernel code. This will remove the native IPsec stack and replace it
+with KLIPS.</LI>
+<LI>
+install the FreeS/WAN <A HREF="ipsec.html#parts">userland tools</A> 
+(keying daemon and supporting 
+scripts) for use with 
+<A HREF="http://lartc.org/howto/lartc.ipsec.html">2.6 kernel native IPsec</A>,
+</LI>
+</UL>
+See also these <A HREF="2.6.known-issues">known issues with 2.6</A>.
+<LI>have root access to your Linux box</LI>
+<LI>choose the version of FreeS/WAN you wish to install based on
+<A HREF="http://www.freeswan.org/mail.html">mailing list reports</A> <!-- or 
+our updates page (coming soon)--></LI>
+</UL>
+
+<H2>Choose your install method</H2>
+
+<P>There are three basic ways to get FreeS/WAN onto your system:</P>
+<UL>
+<LI>activating and testing a FreeS/WAN that <A HREF="#distroinstall">shipped 
+with your Linux distribution</A></LI>
+<LI><A HREF="#rpminstall">RPM install</A></LI>
+<LI><A HREF="#srcinstall">Install from source</A></LI>
+</UL>
+
+<A NAME="distroinstall"></A><H2>FreeS/WAN ships with some Linuxes</H2>
+
+<P>FreeS/WAN comes with <A HREF="intro.html#distwith">these distributions</A>.
+
+<P>If you're running one of these, include FreeS/WAN in the choices you 
+make during installation, or add it later using the distribution's tools.
+</P>
+
+<H3>FreeS/WAN may be altered...</H3>
+<P>Your distribution may have integrated extra features, such as Andreas
+Steffen's X.509 patch, into FreeS/WAN. It may also use custom
+startup script locations or directory names.</P>
+
+<H3>You might need to create an authentication keypair</H3>
+
+<P>If your FreeS/WAN came with your distribution, you may wish to
+ generate a fresh RSA key pair. FreeS/WAN will use these keys
+ for authentication.
+
+<P>
+To do this, become root, and type:
+</P>
+
+<PRE>    ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
+    chmod 600 /etc/ipsec.secrets</PRE>
+
+<P>where you replace xy.example.com with your machine's fully-qualified 
+domain name. Generate some randomness, for example by wiggling your mouse, 
+to speed the process.
+</P>
+
+<P>The resulting ipsec.secrets looks like:</P>
+<PRE>: RSA   {
+        # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
+        # for signatures only, UNSAFE FOR ENCRYPTION
+        #pubkey=0sAQOFppfeE3cC7wqJi...
+        Modulus: 0x85a697de137702ef0...
+        # everything after this point is secret
+        PrivateExponent: 0x16466ea5033e807...
+        Prime1: 0xdfb5003c8947b7cc88759065...
+        Prime2: 0x98f199b9149fde11ec956c814...
+        Exponent1: 0x9523557db0da7a885af90aee...
+        Exponent2: 0x65f6667b63153eb69db8f300dbb...
+        Coefficient: 0x90ad00415d3ca17bebff123413fc518...
+        }
+# do not change the indenting of that "}"</PRE>
+
+<P>In the actual file, the strings are much longer.</P>
+
+
+<H3>Start and test FreeS/WAN</H3>
+
+<P>You can now <A HREF="install.html#starttest">start FreeS/WAN and 
+test whether it's been successfully installed.</A>.</P>
+
+
+<A NAME="rpminstall"></A><H2>RPM install</H2>
+
+<P>These instructions are for a recent Red Hat with a stock Red Hat kernel.
+We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're 
+running either, install using your distribution's tools.</P>
+ 
+<H3>Download RPMs</H3>
+
+<P>Decide which functionality you need:</P>
+<UL>
+<LI>standard FreeS/WAN RPMs. Use these shortcuts:<BR>
+<UL>
+<LI>(for 2.6 kernels: userland only)<BR>
+ncftpget ftp://ftp.xs4all.nl/pub/crypto/freeswan/binaries/RedHat-RPMs/\*userland*</LI>
+
+<LI>(for 2.4 kernels)<BR>
+ncftpget ftp://ftp.xs4all.nl/pub/crypto/freeswan/binaries/RedHat-RPMs/`uname -r | tr -d 'a-wy-z'`/\*</LI>
+<LI>
+or view all the offerings at our
+<A href="ftp://ftp.xs4all.nl/pub/crypto/freeswan/binaries/RedHat-RPMs">FTP site</A>.
+</LI></UL>
+</LI>
+<LI>unofficial
+<A href="http://www.freeswan.ca/download.php">Super FreeS/WAN</A> 
+RPMs, which include Andreas Steffen's X.509 patch and more. 
+Super FreeS/WAN RPMs do not currently include 
+<A HREF="glossary.html#NAT.gloss">Network Address Translation</A>
+(NAT) traversal, but Super FreeS/WAN source does.</LI>
+</UL>
+
+<A NAME="2.6.rpm"></A>
+<P>For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:</P>
+<PRE>    freeswan-userland-2.04.9-0.i386.rpm</PRE>
+
+<P>Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 
+<A HREf="2.6.known-issues">2.6.known-issues</A>, and the latest
+<A HREF="http://www.freeswan.org/mail.html">mailing list reports</A>.</P>                                                                                
+<P>Change to your new FreeS/WAN directory, and make and install the 
+
+<P>For 2.4 kernels, get both kernel and userland RPMs.
+Check your kernel version with</P>
+<PRE>    uname -r</PRE>
+
+<P>Get a kernel module which matches that version. For example:</P>
+<PRE>    freeswan-module-2.04_2.4.20_20.9-0.i386.rpm</PRE>
+<P>Note: These modules 
+<B>will only work on the Red Hat kernel they were built for</B>,
+since they are very sensitive to small changes in the kernel.</P>
+
+
+<P>Get FreeS/WAN utilities to match. For example:</P>
+<PRE>    freeswan-userland-2.04_2.4.20_20.9-0.i386.rpm</PRE>
+
+
+<H3>For freeswan.org RPMs: check signatures</H3>
+
+<P>While you're at our ftp site, grab the RPM signing key</P>
+<PRE>    freeswan-rpmsign.asc</PRE>
+
+<P>If you're running RedHat 8.x or later, import this key into the RPM 
+database:</P>
+<PRE>    rpm --import freeswan-rpmsign.asc</PRE>
+ 
+<P>For RedHat 7.x systems, you'll need to add it to your 
+<A HREF="glossary.html#PGP">PGP</A> keyring:</P>
+<PRE>    pgp -ka freeswan-rpmsign.asc</PRE>
+
+
+<P>Check the digital signatures on both RPMs using:</P>
+<PRE>    rpm --checksig freeswan*.rpm </PRE>
+
+<P>You should see that these signatures are good:</P>
+<PRE>    freeswan-module-2.04_2.4.20_20.9-0.i386.rpm: pgp md5 OK
+    freeswan-userland-2.04_2.4.20_20.9-0.i386.rpm: pgp md5 OK</PRE>
+
+
+<H3>Install the RPMs</H3>
+
+<P>Become root:</P>
+<PRE>    su</PRE>
+
+<P>For a first time install, use:</P>
+<PRE>    rpm -ivh freeswan*.rpm</PRE>
+
+<P>To upgrade existing RPMs (and keep all .conf files in place), use:</P>
+<PRE>    rpm -Uvh freeswan*.rpm</PRE>
+
+<P>If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems,
+see <A HREF="upgrading.html#upgrading.rpms">this note</A>.</P>
+
+
+<H3>Start and Test FreeS/WAN</H3>
+
+<P>Now, <A HREF="install.html#starttest">start FreeS/WAN and test your 
+install</A>.</P>
+
+
+<A NAME="srcinstall"></A><H2>Install from Source</H2>
+<!-- Most of this section, along with "Start and Test", can replace 
+INSTALL. -->
+
+<H3>Decide what functionality you need</H3>
+
+<P>Your choices are:</P>
+<UL>
+<LI><A HREF="ftp://ftp.xs4all.nl/pub/crypto/freeswan">standard 
+FreeS/WAN</A>,</LI>
+<LI>standard FreeS/WAN plus any of these
+ <A HREF="web.html#patch">user-supported patches</A>, or</LI>
+<LI><A HREF="http://www.freeswan.ca/download">Super FreeS/WAN</A>,
+an unofficial FreeS/WAN pre-patched with many of the above. Provides 
+additional algorithms, X.509, SA deletion, dead peer detection, and 
+<A HREF="glossary.html#NAT.gloss">Network Address Translation</A>
+(NAT) traversal.</LI>
+</UL>
+
+<H3>Download FreeS/WAN</H3>
+
+<P>Download the source tarball you've chosen, along with any patches.</P>
+
+<H3>For freeswan.org source: check its signature</H3>
+
+<P>While you're at our ftp site, get our source signing key</P>
+<PRE>    freeswan-sigkey.asc</PRE>
+
+<P>Add it to your PGP keyring:</P>
+<PRE>    pgp -ka freeswan-sigkey.asc</PRE>
+
+
+<P>Check the signature using:</P>
+<PRE>    pgp freeswan-2.04.tar.gz.sig freeswan-2.04.tar.gz</PRE>
+<P>You should see something like:</P>
+<PRE>    Good signature from user "Linux FreeS/WAN Software Team (build@freeswan.org)".
+    Signature made 2002/06/26 21:04 GMT using 2047-bit key, key ID 46EAFCE1</PRE>
+<!-- Note to self: build@freeswan.org has angled brackets in the original.
+     Changed because it conflicts with HTML tags. -->
+
+<H3>Untar, unzip</H3>
+
+<P>As root, unpack your FreeS/WAN source into <VAR>/usr/src</VAR>.</P>
+<PRE>    su
+    mv freeswan-2.04.tar.gz /usr/src
+    cd /usr/src
+    tar -xzf freeswan-2.04.tar.gz
+</PRE>
+
+<H3>Patch if desired</H3>
+
+<P>Now's the time to add any patches. The contributor may have special 
+instructions, or you may simply use the patch command.</P>
+
+<H3>... and Make</H3>
+
+<P>Choose one of the methods below.</P>
+
+<H4>Userland-only Install for 2.6 kernels</H4>
+<A NAME="2.6.src"></A>
+
+<P>Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 
+<A HREf="2.6.known-issues">2.6.known-issues</A>, and the latest
+<A HREF="http://www.freeswan.org/mail.html">mailing list reports</A>.</P>                                                                                
+<P>Change to your new FreeS/WAN directory, and make and install the 
+FreeS/WAN userland tools.</P>
+<PRE>    cd /usr/src/freeswan-2.04
+    make programs
+    make install</PRE>
+                                                                                
+<P>Now, <A HREF="install.html#starttest">start FreeS/WAN and
+test your install</A>.</P>
+
+
+
+<H4>KLIPS install for 2.2, 2.4, or 2.6 kernels</H4>
+
+<A NAME="modinstall"></A>
+
+<P>To make a modular version of KLIPS, along with other FreeS/WAN programs 
+you'll need, use the command sequence below. This will
+change to your new FreeS/WAN directory, make the FreeS/WAN module (and other
+stuff), and install it all.</P>
+<PRE>    cd /usr/src/freeswan-2.04
+    make oldmod
+    make minstall</PRE>
+ 
+<P><A HREF="install.html#starttest">Start FreeS/WAN and 
+test your install</A>.</P>
+
+
+
+<P>To link KLIPS statically into your kernel (using your old kernel settings), 
+and install other FreeS/WAN components, do:
+</P>
+<PRE>    cd /usr/src/freeswan-2.04
+    make oldmod
+    make minstall</PRE>
+
+
+<P>Reboot your system and <A HREF="install.html#testonly">test your 
+install</A>.</P>
+
+<P>For other ways to compile KLIPS, see our Makefile.</P>
+
+
+
+<A name="starttest"></A><H2>Start FreeS/WAN and test your install</H2>
+
+<P>Bring FreeS/WAN up with:</P>
+<PRE>    service ipsec start</PRE>
+
+<P>This is not necessary if you've rebooted.</P>
+
+<A name="testonly"></A><H2>Test your install</H2>
+
+<P>To check that you have a successful install, run:</P>
+<PRE>    ipsec verify</PRE>
+
+<P>You should see at least:</P>
+<PRE>
+    Checking your system to see if IPsec got installed and started correctly
+    Version check and ipsec on-path                             [OK]
+    Checking for KLIPS support in kernel                        [OK]
+    Checking for RSA private key (/etc/ipsec.secrets)           [OK]
+    Checking that pluto is running                              [OK]
+</PRE>
+
+<P>If any of these first four checks fails, see our 
+<A href="trouble.html#install.check">troubleshooting guide</A>.
+</P>
+
+
+<H2>Making FreeS/WAN play well with others</H2>
+
+<P>There are at least a couple of things on your system that might 
+interfere with FreeS/WAN, and now's a good time to check these:</P>
+<UL>
+  <LI>Firewalling. You need to allow UDP 500 through your firewall, plus 
+ ESP (protocol 50) and AH (protocol 51). For more information, see our
+  updated firewalls document (coming soon).
+ </LI>
+  <LI>Network address translation. 
+Do not NAT the packets you will be tunneling.</LI>
+</UL>
+
+
+<H2>Configure for your needs</H2>
+
+<P>You'll need to configure FreeS/WAN for your local site. Have a look at our 
+<A HREF="quickstart.html">opportunism quickstart guide</A> to see if that
+easy method is right for your needs. Or, see how to <A HREF="config.html">
+configure a network-to-network or Road Warrior style VPN</A>.
+</P>
+
+
+
+
+</BODY>
+</HTML>
diff --git a/doc/src/interop.html b/doc/src/interop.html
new file mode 100644
index 000000000..dd4f8c577
--- /dev/null
+++ b/doc/src/interop.html
@@ -0,0 +1,1802 @@
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>FreeS/WAN interoperation Grid</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, FreeSWAN, interoperation">
+  <!--
+
+  Written by Claudia Schmeing for the Linux FreeS/WAN project
+  With notes from Sandy Harris.
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: interop.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+
+<body>
+<A NAME="interop"></A><H1>Interoperating with FreeS/WAN</H1>
+
+
+<P>The FreeS/WAN project needs you! We rely on the user community to keep
+up to date. Mail users@lists.freeswan.org with your
+interop success stories.</P>
+
+<P><STRONG>Please note</STRONG>: Most of our interop examples feature 
+Linux FreeS/WAN 1.x config files. You can convert them to 2.x files fairly 
+easily with the patch in our 
+<A HREF="upgrading.html#ipsec.conf_v2">Upgrading Guide</A>.
+</P>
+
+<H2>Interop at a Glance</H2>
+
+
+
+<TABLE BORDER="1">
+
+<TR>
+<TD>&nbsp;</TD>
+<TD colspan="5">FreeS/WAN VPN</TD>
+<TD>Road Warrior</TD>
+<TD>OE</TD>
+</TR>
+
+<TR>
+<TD>&nbsp;</TD>
+<TD>PSK</TD>
+<TD>RSA Secret</TD>
+<TD>X.509<BR><SMALL><A HREF="#interoprules">(requires patch)</A></SMALL></TD>
+<TD>NAT-Traversal<BR><SMALL><A HREF="#interoprules">(requires patch)</A></SMALL></TD>
+<TD>Manual<BR>Keying</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+</TR>
+
+
+<TR><TD colspan="8">More Compatible</TD></TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#freeswan">FreeS/WAN</A>
+<A NAME="freeswan.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#isakmpd">isakmpd (OpenBSD)</A>
+<A NAME="isakmpd.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No&nbsp;&nbsp;&nbsp;&nbsp;</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#kame">Kame (FreeBSD,
+<BR>NetBSD, MacOSX)
+<BR> <SMALL>aka racoon</SMALL></A>
+<A NAME="kame.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#mcafee">McAfee VPN<BR><SMALL>was PGPNet</SMALL></A>
+<A NAME="mcafee.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#microsoft">Microsoft <BR>Windows 2000/XP</A>
+<A NAME="microsoft.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+<TR>
+<TD><A HREF="#ssh">SSH Sentinel</A>
+<A NAME="ssh.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#cccc00">Maybe</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#safenet">Safenet SoftPK<BR>/SoftRemote</A>
+<A NAME="safenet.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+
+<TR><TD colspan="8">Other</TD></TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#6wind">6Wind</A>
+<A NAME="6wind.top">&nbsp;</A></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#alcatel">Alcatel Timestep</A>
+<A NAME="alcatel.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#apple">Apple Macintosh<br>System 10+</A>
+<A NAME="apple.top">&nbsp;</A></TD>
+<TD><FONT color="#cccc00">Maybe</FONT></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#cccc00">Maybe</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cccc00">Maybe</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#ashleylaurent">AshleyLaurent <BR>VPCom</A>
+<A NAME="ashleylaurent.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#borderware">Borderware</A>
+<A NAME="borderware.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+<!--
+http://www.cequrux.com/vpn-guides.php3
+"coming soon" guide to connect with FreeS/WAN.
+-->
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#checkpoint">Check Point FW-1/VPN-1</A>
+<A NAME="checkpoint.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#cisco">Cisco with 3DES</A>
+<A NAME="cisco.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#cccc00">Maybe</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cccc00">Maybe</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#equinux">Equinux VPN Tracker <BR>
+(for Mac OS X)
+</A>
+<A NAME="equinux.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cccc00">Maybe</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#fsecure">F-Secure</A>
+<A NAME="fsecure.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cccc00">Maybe</FONT></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#gauntlet">Gauntlet GVPN</A>
+<A NAME="gauntlet.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#aix">IBM AIX</A>
+<A NAME="aix.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cccc00">Maybe</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#as400">IBM AS/400</A>
+<A NAME="as400">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#intel">Intel Shiva<BR>LANRover/Net Structure</A>
+<A NAME="intel.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#lancom">LanCom (formerly ELSA)</A>
+<A NAME="lancom.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#linksys">Linksys</A>
+<A NAME="linksys.top">&nbsp;</A></TD>
+<TD><FONT color="#cccc00">Maybe</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#lucent">Lucent</A>
+<A NAME="lucent.top">&nbsp;</A></TD>
+<TD><FONT color="#cccc00">Partial</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#netasq">Netasq</A>
+<A NAME="netasq.top">&nbsp;</A></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#netcelo">netcelo</A>
+<A NAME="netcelo.top">&nbsp;</A></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#netgear">Netgear fvs318</A>
+<A NAME="netgear.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#netscreen">Netscreen 100<BR>or 5xp</A>
+<A NAME="netscreen.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cccc00">Maybe</FONT></TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#nortel">Nortel Contivity</A>
+<A NAME="nortel.top">&nbsp;</A></TD>
+<TD><FONT color="#cccc00">Partial</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD><FONT color="#cccc00">Maybe</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#radguard">RadGuard</A>
+<A NAME="radguard.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#raptor">Raptor</A>
+<A NAME="raptor">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#redcreek">Redcreek Ravlin</A>
+<A NAME="redcreek.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT><FONT color="#cccc00">/Partial</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#sonicwall">SonicWall</A>
+<A NAME="sonicwall.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cccc00">Maybe</FONT></TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#sun">Sun Solaris</A>
+<A NAME="sun.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#symantec">Symantec</A>
+<A NAME="symantec.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#watchguard">Watchguard <BR>Firebox</A>
+<A NAME="watchguard.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#xedia">Xedia Access Point<BR>/QVPN</A>
+<A NAME="xedia.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+<TR>
+<TD><A HREF="#zyxel">Zyxel Zywall<BR>/Prestige</A>
+<A NAME="zyxel.top">&nbsp;</A></TD>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE
+
+
+<TR>
+<TD><A HREF="#sample">sample</A></TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+<TD><FONT color="#cc0000">No</FONT></TD>
+</TR>
+
+-->
+
+<TR>
+<TD>&nbsp;</TD>
+<TD>PSK</TD>
+<TD>RSA Secret</TD>
+<TD>X.509<BR><SMALL><A HREF="#interoprules">(requires patch)</A></SMALL></TD>
+<TD>NAT-Traversal<BR><SMALL><A HREF="#interoprules">(requires patch)</A></SMALL></TD>
+<TD>Manual<BR>Keying</TD>
+<TD>&nbsp;</TD>
+<TD>&nbsp;</TD>
+</TR>
+
+<TR>
+<TD>&nbsp;</TD>
+<TD colspan="5">FreeS/WAN VPN</TD>
+<TD>Road Warrior</TD>
+<TD>OE</TD>
+</TR>
+
+
+
+<!-- PSK  RSA  X.509  NAT-T  Manual  RW  OE -->
+
+</TABLE>
+
+
+
+
+<H3>Key</H3>
+<TABLE BORDER="1">
+
+<TR>
+<TD><FONT color="#00cc00">Yes</FONT></TD>
+<TD>People report that this works for them.</TD>
+</TR>
+
+<TR>
+<TD>[Blank]</TD>
+<TD>We don't know.</TD>
+</TR>
+
+<TR>
+<TD><FONT color="#cc0000">No</FONT></TD>
+<TD>We have reason to believe
+it was, at some point, not possible to get this to work.</TD>
+</TR>
+
+<TR>
+<TD><FONT color="#cccc00">Partial</FONT></TD>
+<TD>Partial success. For example, a connection can be 
+created from one end only.</TD>
+</TR>
+
+<TR>
+<TD><FONT color="#00cc00">Yes</FONT><FONT color="#cccc00">/Partial</FONT></TD>
+<TD>Mixed reports.</TD>
+</TR>
+
+
+<TR>
+<TD><FONT color="#cccc00">Maybe</FONT></TD>
+<TD>We think the answer is "yes", but need confirmation.</TD>
+</TR>
+
+
+</TABLE>
+
+<A NAME="interoprules"></A><h2>Basic Interop Rules</h2>
+
+<P>Vanilla
+FreeS/WAN implements <A HREF="compat.html#compat">these parts</A> of the
+IPSec specifications. You can add more with 
+<A HREF="http://www.freeswan.ca">Super FreeS/WAN</A>, 
+but what we offer may be enough for many users.</P>
+<UL>
+<LI>
+To use X.509 certificates with FreeS/WAN, you will need 
+the <A HREF="http://www.strongsec.org/freeswan">X.509 patch</a> 
+or <A HREF="http://www.freeswan.ca">Super FreeS/WAN</A>,
+which includes that patch.</LI>
+<LI>
+To use 
+<A HREF="glossary.html#NAT.gloss">Network Address Translation</A> 
+(NAT) traversal
+with FreeS/WAN, you will need Arkoon Network Security's
+<A HREF="http://open-source.arkoon.net">NAT traversal patch</A>
+or <A HREF="http://www.freeswan.ca">Super FreeS/WAN</A>, which includes it.
+</LI>
+</UL>
+
+
+<P>We offer a set of proposals which is not user-adjustable, but covers
+all combinations that we can offer.
+FreeS/WAN always proposes triple DES encryption and
+Perfect Forward Secrecy (PFS).
+In addition, we propose Diffie Hellman groups 5 and 2 
+(in that order), and MD5 and SHA-1 hashes.
+We accept the same proposals, in the same order of preference. 
+</P>
+
+<P>Other interop notes:</P>
+<UL>
+<LI>
+A <A HREF="http://lists.freeswan.org/archives/users/2003-September/msg00462.html">SHA-1 
+bug in FreeS/WAN 2.00, 2.01 and 2.02</A> may affect some
+interop scenarios. It does not affect 1.x versions, and is fixed in 2.03 and
+later.
+</LI>
+<LI>
+Some other implementations will close a connection with FreeS/WAN
+after some time. This may be a problem with rekey lifetimes. Please see
+<A HREF="http://lists.freeswan.org/archives/users/2003-October/msg00293.html">
+this tip</A> and 
+<A HREF="http://lists.freeswan.org/pipermail/users/2001-December/005758.html">
+this workaround</A>.
+</LI>
+</UL>
+
+<H2>Longer Stories</H2>
+
+
+<H3>For <EM>More Compatible</EM> Implementations</H3>
+
+
+<H4><A NAME="freeswan">FreeS/WAN</A></H4>
+
+<P>
+See our documentation at <A HREF="http://www.freeswan.org">freeswan.org</A>
+and the Super FreeS/WAN docs at 
+<A HREF="http://www.freeswan.ca">freeswan.ca</A>.
+Some user-written HOWTOs for FreeS/WAN-FreeS/WAN connections
+are listed in <A HREF="intro.html#howto">our Introduction</A>.
+</P>
+
+<P>See also:</P>
+
+<UL>
+<LI>
+<A HREF="http://lugbe.ch/action/reports/ipsec_htbe.phtml">A German FreeS/WAN-FreeS/WAN page by Markus Wernig (X.509)</A>
+</LI>
+</UL>
+
+
+<P><A HREF="#freeswan.top">Back to chart</A></P>
+
+
+<H4><A NAME="isakmpd">isakmpd (OpenBSD)</A></H4>
+
+<P><A HREF="http://www.openbsd.org/faq/faq13.html">OpenBSD FAQ: Using IPsec</A><BR>
+<A HREF="http://www.rommel.stw.uni-erlangen.de/~hshoexer/ipsec-howto/HOWTO.html">Hans-Joerg Hoexer's interop Linux-OpenBSD (PSK)</A><BR>
+<A HREF="http://www.segfault.net/ipsec/">Skyper's configuration (PSK)</A>
+<BR>
+<A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+French page with configs (X.509)</A>
+
+
+</P>
+
+<P><A HREF="#isakmpd.top">Back to chart</A></P>
+
+
+<H4><A NAME="kame">Kame</A></H4>
+
+<UL>
+<LI>For FreeBSD and NetBSD. Ships with Mac OS X; see also our
+<A HREF="#apple">Mac</A> section.</LI>
+<LI>Also known as <EM>racoon</EM>, its keying daemon.</LI>
+</UL>
+
+<P><A HREF="http://www.kame.net">Kame homepage, with FAQ</A><BR>
+<A HREF="http://www.netbsd.org/Documentation/network/ipsec">NetBSD's IPSec FAQ</A><BR>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/12/msg00560.html">Ghislaine's post explaining some interop peculiarities</A>
+</P>
+<P>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/09/msg00511.html">Itojun's Kame-FreeS/WAN interop tips (PSK)</A><BR>
+<A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2000">Ghislaine Labouret's French page with links to matching FreeS/WAN and Kame configs (RSA)</A><BR>
+<A HREF="http://lugbe.ch/lostfound/contrib/freebsd_router/">Markus Wernig's
+HOWTO (X.509, BSD gateway)</A><BR>
+<A HREF="http://web.morgul.net/~frodo/docs/kame+freeswan_interop.html">Frodo's Kame-FreeS/WAN interop (X.509)</A><BR>
+<A HREF="http://www.wavesec.org/kame.phtml">Kame as a WAVEsec client.</A>
+</P>
+
+<P><A HREF="#kame.top">Back to chart</A></P>
+
+
+<H4><A NAME="mcafee">PGPNet/McAfee</A></H4>
+
+<P>
+<UL>
+<LI>Now called McAfee VPN Client.</LI>
+<LI>PGPNet also came in a freeware version which did not support subnets</LI>
+<LI>To support dhcp-over-ipsec, you need the X.509 patch, which is included in
+<A HREF="http://www.freeswan.ca">Super FreeS/WAN</A>.
+</LI>
+</UL>
+<P>
+<A HREF="http://www.freeswan.ca/docs/WindowsInterop">Tim Carr's Windows Interop Guide (X.509)</A><BR>
+<A HREF="http://www.rommel.stw.uni-erlangen.de/~hshoexer/ipsec-howto/HOWTO.html#Interop2"
+>Hans-Joerg Hoexer's Guide for Linux-PGPNet (PSK)</A><BR>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/04/msg00339.html">Kai Martius' instructions using RSA Key-Extractor Tool (RSA)</A><BR>
+&nbsp;&nbsp;&nbsp;&nbsp;<A HREF="http://www.zengl.net/freeswan/english.html">Christian Zeng's page (RSA)</A> based on Kai's work. English or German.<BR>
+<A HREF="http://tirnanog.ls.fi.upm.es/CriptoLab/Biblioteca/InfTech/InfTech_CriptoLab.htm">
+Oscar Delgado's PDF (X.509, no configs)</A><BR>
+<A HREF="http://www-ec.njit.edu/~rxt1077/Howto.txt">Ryan's HOWTO for FreeS/WAN-PGPNet (X.509)</A>. Through a Linksys Router with IPsec Passthru enabled.<BR>
+<A HREF="http://jixen.tripod.com/#RW-PGP-to-Fwan">Jean-Francois Nadeau's Practical Configuration (Road Warrior with PSK)</A><BR>
+<A HREF="http://www.evolvedatacom.nl/freeswan.html#toc">Wouter Prins' HOWTO (Road Warrior with X.509)</A><BR>
+</P>
+<P>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/01/msg00271.html">Rekeying problem with FreeS/WAN and older PGPNets</A><BR>
+</P>
+
+<P><A HREF="http://www.strongsec.com/freeswan/dhcprelay/index.htm">
+DHCP over IPSEC HOWTO for FreeS/WAN (requires X.509 and dhcprelay patches)
+</A>
+</P>
+
+<P><A HREF="#mcafee.top">Back to chart</A></P>
+
+
+<H4><A NAME="microsoft">Microsoft Windows 2000/XP</A></H4>
+
+<UL>
+<LI>IPsec comes with Win2k, and with XP Support Tools. May require
+<A HREF="http://www.microsoft.com/windows2000/downloads/recommended/encryption/default.asp"> High Encryption Pack</A>. WinXP users have also reported better
+results with Service Pack 1.</LI>
+<LI>The Road Warrior setup works either way round. Windows (XP or 2K) IPsec
+can connect as a Road Warrior to FreeS/WAN. 
+However, FreeS/WAN can also successfully connect as a Road 
+Warrior to Windows IPsec (see Nate Carlson's configs below).</LI>
+<LI>FreeS/WAN version 1.92 or later is required to avoid an interoperation
+problem with Windows native IPsec. Earlier FreeS/WAN versions 
+did not process the Commit Bit as Windows native IPsec expected.</LI>
+</UL>
+
+<P>
+<A HREF="http://www.freeswan.ca/docs/WindowsInterop">Tim Carr's Windows Interop Guide (X.509)</A><BR>
+
+<A HREF="http://ipsec.math.ucla.edu/services/ipsec.html">James Carter's
+instructions (X.509, NAT-T)</A><BR>
+
+<A HREF="http://jixen.tripod.com/#Win2000-Fwan">
+Jean-Francois Nadeau's Net-net Configuration (PSK)</A><BR>
+
+<A HREF="http://security.nta.no/freeswan-w2k.html">
+Telenor's Node-node Config (Transport-mode PSK)</A><BR>
+
+<A HREF="http://vpn.ebootis.de">Marcus Mueller's HOWTO using his VPN config tool (X.509).</A> Tool also works with PSK.<BR>
+
+<A HREF="http://www.natecarlson.com/include/showpage.php?cat=linux&page=ipsec-x509">
+Nate Carlson's HOWTO using same tool (Road Warrior with X.509)</A>. Unusually,
+FreeS/WAN is the Road Warrior here.<BR>
+
+<A HREF="http://tirnanog.ls.fi.upm.es/CriptoLab/Biblioteca/InfTech/InfTech_CriptoLab.htm">
+Oscar Delgado's PDF (X.509, no configs)</A><BR>
+
+<A HREF="http://lists.freeswan.org/pipermail/users/2003-July/022425.html">Tim Scannell's Windows XP Additional Checklist (X.509)</A><BR>
+</P>
+
+<!-- Note to self: Include L2TP references? -->
+
+<P>
+<A HREF="http://www.microsoft.com/windows2000/en/server/help/default.asp?url=/windows2000/en/server/help/sag_TCPIP_ovr_secfeatures.htm">
+Microsoft's page on Win2k TCP/IP security features</A><BR>
+
+<A HREF="http://support.microsoft.com/support/kb/articles/Q257/2/25.ASP">
+Microsoft's Win2k IPsec debugging tips</A><BR>
+
+<!-- Alt-URL http://support.microsoft.com/default.aspx?scid=kb;EN-US;q257225
+Perhaps newer? -->
+
+<A HREF="http://www.wired.com/news/technology/0,1282,36336,00.html">MS VPN may fall back to 1DES</A>
+</P>
+
+<P><A HREF="#microsoft.top">Back to chart</A></P>
+
+
+<H4><A NAME="ssh">SSH Sentinel</A></H4>
+
+<UL>
+<LI>Popular and well tested.</LI>
+<LI>Also rebranded in <A HREF="http://www.zyxel.com">Zyxel Zywall</A>.
+Our Zyxel interop notes are <A HREF="#zyxel">here</A>.</LI>
+<LI>
+SSH supports IPsec-over-UDP NAT traversal.
+</LI>
+<LI>There is this 
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/12/msg00370.html">
+potential problem</A> if you're not using the Legacy Proposal option.
+</UL>
+
+<P>
+<A HREF="http://www.ssh.com/support/sentinel/documents.cfm">SSH's Sentinel-FreeSWAN interop PDF (X.509)</A><BR>
+<A HREF="http://www.nadmm.com/show.php?story=articles/vpn.inc">Nadeem Hassan's 
+SUSE-to-Sentinel article (Road warrior with X.509)</A><BR>
+<A HREF="http://www.zerozone.it/documents/Linux/HowTo/VPN-IPsec-Freeswan-HOWTO.html">O-Zone's Italian HOWTO (Road Warrior, X.509, DHCP)</A><BR>
+</P>
+
+
+<P><A HREF="#ssh.top">Back to chart</A></P>
+
+
+
+<H4><A NAME="safenet">Safenet SoftPK/SoftRemote</A></H4>
+
+<UL>
+<LI>People recommend SafeNet as a low cost Windows client.</LI>
+<LI>SoftRemote seems to be the newer name for SoftPK.</LI>
+</UL>
+
+<P>
+<A HREF="http://lists.freeswan.org/pipermail/users/2001-November/005061.html">
+Whit Blauvelt's SoftRemote tips</A><BR>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-October/015591.html">
+Tim Wilson's tips (X.509)</A>
+<A HREF="http://lists.freeswan.org/archives/users/2003-October/msg00607.html">Workaround for a "gotcha"</A>
+</P>
+
+<P>
+<A HREF="http://jixen.tripod.com/#Rw-IRE-to-Fwan">Jean-Francois Nadeau's 
+Practical Configuration (Road Warrior with PSK)</A><BR>
+<A HREF="http://www.terradoncommunications.com/security/whitepapers/safe_net-to-free_swan.pdf">
+Terradon Communications' PDF (Road Warrior with PSK)</A><BR>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-October/?????.html">
+Seaan.net's PDF (Road Warrior to Subnet, with PSK)
+</A><BR>
+<A HREF="http://www.redbaronconsulting.com/freeswan/fswansafenet.pdf">
+Red Baron Consulting's PDF (Road Warrior with X.509)</A>
+</P>
+
+<P><A HREF="#safenet.top">Back to chart</A></P>
+
+
+
+
+
+
+
+
+<H3>For <EM>Other Implementations</EM></H3>
+
+
+
+<H4><A NAME="6wind">6Wind</A></H4>
+
+<P>
+
+<A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+French page with configs (X.509)</A>
+
+</P>
+
+<P><A HREF="#6wind.top">Back to chart</A></P>
+
+
+
+<H4><A NAME="alcatel">Alcatel Timestep</A></H4>
+
+<P>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-June/011878.html">
+Alain Sabban's settings (PSK or PSK road warrior; through static NAT)</A><BR>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/1999/06/msg00100.html">
+Derick Cassidy's configs (PSK)</A><BR>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/1999/08/msg00194.html">
+David Kerry's Timestep settings (PSK)</A>
+<BR>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-August/013711.html">
+Kevin Gerbracht's ipsec.conf (X.509)</A>
+</P>
+
+<P><A HREF="#alcatel.top">Back to chart</A></P>
+
+
+
+<H4><A NAME="apple">Apple Macintosh System 10+</A></H4>
+
+<UL>
+<LI>Since the system is based on FreeBSD, this should
+interoperate <A HREF="#kame">just like FreeBSD</A>.
+</LI>
+
+<LI>
+To use Appletalk over IPsec tunnels,
+<A HREF="http://lists.freeswan.org/pipermail/users/2001-November/005116.html">run 
+it over TCP/IP</A>, or use 
+Open Door Networks' Shareway IP tool, 
+<A HREF="http://lists.freeswan.org/pipermail/users/2001-November/005426.html">described 
+here.</A>
+</LI>
+
+<LI>See also the <A HREF="#equinux">Equinux VPN Tracker</A> 
+for Mac OS X.</LI> 
+</UL>
+
+
+<P>
+<A HREF="http://ipsec.math.ucla.edu/services/ipsec.html">James Carter's
+instructions (X.509, NAT-T)</A>
+</P>
+
+
+<P><A HREF="#apple.top">Back to chart</A></P>
+
+
+
+
+
+
+<H4><A NAME="ashleylaurent">AshleyLaurent VPCom</A></H4>
+
+<P>
+<A HREF="http://www.ashleylaurent.com/newsletter/01-28-00.htm">
+Successful interop report, no details</A>
+</P>
+
+<P><A HREF="#ashleylaurent.top">Back to chart</A></P>
+
+
+<H4><A NAME="borderware">Borderware</A></H4>
+
+<UL>
+<LI>I suspect the Borderware client is a rebranded Safenet.
+If that's true, our <A HREF="#safenet">Safenet section</A> will help.</LI>
+</UL>
+
+<P>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-March/008288.html">
+Philip Reetz' configs (PSK)</A><BR>
+
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/09/msg00217.html">
+Borderware server does not support FreeS/WAN road warriors</A><BR>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-February/007733.html">
+Older Borderware may not support Diffie Hellman groups 2, 5</A><BR>
+</P>
+
+
+<P><A HREF="#borderware.top">Back to chart</A></P>
+
+
+
+<H4><A NAME="checkpoint">Check Point VPN-1 or FW-1</A></H4>
+
+<UL>
+<LI>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/02/msg00099.html">
+Caveat about IP-range inclusion on Check Point.</A>
+</LI>
+<LI>
+Some versions of Check Point may require an aggressive mode patch to 
+interoperate with FreeS/WAN.<BR>
+<A HREF="http://www.freeswan.ca/code/super-freeswan">Super FreeS/WAN</A> 
+now features this patch.
+<!--
+<A HREF="http://www.freeswan.ca/patches/aggressivemode">Steve Harvey's 
+aggressive mode patch for FreeS/WAN 1.5</A>
+-->
+</LI>
+<LI>
+<LI>A Linux FreeS/WAN-Checkpoint connection may close after some time. Try
+<A HREF="http://lists.freeswan.org/archives/users/2003-October/msg00293.html">this tip</A> toward a workaround.
+</LI>
+</UL>
+
+<P>
+<A HREF="http://www.fw-1.de/aerasec/ng/vpn-freeswan/CPNG+Linux-FreeSWAN.html">
+AERAsec's Firewall-1 NG site (PSK, X.509, Road Warrior with X.509, 
+other algorithms)</A><BR>
+&nbsp;&nbsp;&nbsp;&nbsp;
+<A HREF="http://www.fw-1.de/aerasec/ng/vpn-freeswan/CPNG+Linux-FreeSWAN.html#support-matrix">
+AERAsec's detailed Check Point-FreeS/WAN support matrix</A><BR>
+<A HREF="http://support.checkpoint.com/kb/docs/public/firewall1/4_1/pdf/fw-linuxvpn.pdf">Checkpoint.com PDF: Linux as a VPN Client to FW-1 (PSK)</A><BR>
+
+<A HREF="http://www.phoneboy.com">PhoneBoy's Check Point FAQ (on Check Point 
+only, not FreeS/WAN)</A><BR>
+
+</P>
+
+<P>
+<A HREF="http://lists.freeswan.org/pipermail/users/2001-August/002351.html">Chris 
+Harwell's tips & FreeS/WAN configs (PSK)</A><BR>
+
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-April/009362.html">Daniel 
+Tombeil's configs (PSK)</A>
+
+</P>
+
+<P><A HREF="#checkpoint.top">Back to chart</A></P>
+
+
+<H4><A NAME="cisco">Cisco</A></H4>
+
+<UL>
+<LI>
+Cisco supports IPsec-over-UDP NAT traversal.
+</LI>
+<LI>Cisco VPN Client appears to use nonstandard IPsec and 
+does not work with FreeS/WAN. <A HREF="https://mj2.freeswan.org/archives/2003-August/maillist.html">This message</A> concerns Cisco VPN Client 4.01.
+<!-- fix link -->
+</LI>
+<LI>A Linux FreeS/WAN-Cisco connection may close after some time.
+<A HREF="http://lists.freeswan.org/pipermail/users/2001-December/005758.html">
+Here</A>
+is a workaround, and 
+<A HREF="http://lists.freeswan.org/archives/users/2003-October/msg00293.html">here</A>
+ is another comment on the same subject.</LI>
+<LI><A HREF="http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120t/120t2/3desips.htm">Older Ciscos</A> 
+purchased outside the United States may not have 3DES, which FreeS/WAN requires.</LI>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2001-June/000406.html">RSA keying may not be possible between Cisco and FreeS/WAN.</A>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2001-October/004357.html">In 
+ipsec.conf, VPN3000 DN (distinguished name) must be in binary (X.509 only)</A></LI>
+
+
+</UL>
+
+
+<P>
+<A HREF="http://rr.sans.org/encryption/cisco_router.php">SANS Institute HOWTO (PSK).</A> Detailed, with extensive references.<BR>
+<A HREF="http://www.worldbank.ro/IPSEC/cisco-linux.txt">Short HOWTO (PSK)</A><BR>
+<A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+French page with configs for Cisco IOS, PIX and VPN 3000 (X.509)</A>
+<BR>
+
+<A HREF="http://lists.freeswan.org/pipermail/users/2001-August/002966.html">Dave
+McFerren's sample configs (PSK)</A><BR>
+<A HREF="http://lists.freeswan.org/pipermail/users/2001-September/003422.html">Wolfgang 
+Tremmel's sample configs (PSK road warrior)</A><BR>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/11/msg00578.html">
+Old doc from Pete Davis, with William Watson's updated Tips (PSK)</A><BR>
+</P>
+
+<P><STRONG>Some PIX specific information:</STRONG><BR>
+
+<A HREF="http://www.wlug.org.nz/FreeSwanToCiscoPix">
+Waikato Linux Users' Group HOWTO. Nice detail (PSK)
+</A><BR>
+<A HREF="http://www.johnleach.co.uk/documents/freeswan-pix/freeswan-pix.html">
+John Leach's configs (PSK)
+</A><BR>
+<A HREF="http://www.diverdown.cc/vpn/freeswanpix.html">
+Greg Robinson's settings (PSK)
+</A><BR>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-February/007901.html">
+Scott's ipsec.conf for PIX (PSK, FreeS/WAN side only)</A><BR>
+<A HREF="http://lists.freeswan.org/pipermail/users/2001-October/003949.html">Rick 
+Trimble's PIX and FreeS/WAN settings (PSK)</A><BR>
+</P>
+
+
+
+<P><A href="http://www.cisco.com/public/support/tac">
+Cisco VPN support page</A><BR>
+<A href="http://www.ieng.com/warp/public/707/index.shtml#ipsec">
+Cisco IPsec information page</A>
+</P>
+
+<P><A HREF="#cisco.top">Back to chart</A></P>
+
+
+
+
+<H4><A NAME="equinux">Equinux VPN tracker (for Mac OS X)</A></H4>
+                                                                                
+<UL>
+<LI>Graphical configurator for Mac OS X IPsec. May be an interface
+to the <A HREF="#apple">native Mac OS X IPsec</A>, which is essentially
+<A HREF="#kame">KAME</A>.</LI>
+<LI>To use Appletalk over IPsec tunnels,
+<A HREF="http://lists.freeswan.org/pipermail/users/2001-November/005116.html">run
+it over TCP/IP</A>, or use
+Open Door Networks' Shareway IP tool,
+<A HREF="http://lists.freeswan.org/pipermail/users/2001-November/005426.html">described
+here.</A> </LI>
+</UL>
+
+                                                                                
+<P>
+Equinux provides <A HREF="http://www.equinux.com/download/HowTo_FreeSWAN.pdf">this 
+excellent interop PDF</A> (PSK, RSA, X.509).
+</P>
+                                                                                
+<P><A HREF="#equinux.top">Back to chart</A></P>
+
+
+<H4><A NAME="fsecure">F-Secure</A></H4>
+
+<UL>
+<LI>
+<!-- <A HREF="http://lists.freeswan.org/pipermail/users/2002-February/007596.html"> -->
+F-Secure supports IPsec-over-UDP NAT traversal.
+</LI>
+</UL>
+
+<P><A HREF="http://www.pingworks.de/tech/vpn/vpn.txt">pingworks.de's
+ "Connecting F-Secure's VPN+ to Linux FreeS/WAN" (PSK road warrior)</A><BR>
+&nbsp;&nbsp;&nbsp;&nbsp;<A HREF="http://www.pingworks.de/tech/vpn/vpn.pdf">Same thing as PDF</A><BR>
+<A HREF="http://www.exim.org/pipermail/linux-ipsec/Week-of-Mon-20010122/000061.html">Success report, no detail (PSK)</A><BR>
+<A HREF="http://www.exim.org/pipermail/linux-ipsec/Week-of-Mon-20010122/000041.html">Success report, no detail (Manual)</A>
+</P>
+
+<!-- Other NAT traversers:
+http://lists.freeswan.org/pipermail/users/2002-April/009136.html
+and ssh sentinel:
+http://lists.freeswan.org/pipermail/users/2001-September/003108.html
+-->
+
+<P><A HREF="#fsecure.top">Back to chart</A></P>
+
+
+
+<H4><A NAME="gauntlet">Gauntlet GVPN</A></H4>
+
+<P>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/11/msg00535.html">Richard Reiner's ipsec.conf (PSK)</A>
+<BR>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-June/011434.html">
+Might work without that pesky firewall... (PSK)</A><BR>
+<!-- insert archive link -->
+In late July, 2003 Alexandar Antik reported success interoperating 
+with Gauntlet 6.0 for Solaris (X.509). Unfortunately the message is not 
+properly archived at this time.
+</P>
+
+<P><A HREF="#gauntlet.top">Back to chart</A></P>
+
+
+
+<H4><A NAME="aix">IBM AIX</A></H4>
+
+<P><A HREF="http://www-1.ibm.com/servers/esdd/articles/security.html">
+IBM's "Built-In Network Security with AIX" (PSK, X.509)</A><BR>
+<A HREF="http://www-1.ibm.com/servers/aix/products/ibmsw/security/vpn/faqandtips/#ques20">
+IBM's tip: importing Linux FreeS/WAN settings into AIX's <VAR>ikedb</VAR> 
+(PSK)</A>
+</P>
+
+<P><A HREF="#aix.top">Back to chart</A></P>
+
+
+
+<H4><A NAME="as400">IBM AS/400</A></H4>
+
+<UL>
+<LI>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-April/009106.html">Road
+ Warriors may act flaky</A>.
+</LI>
+</UL>
+
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2002-September/014264.html">
+Richard Welty's tips and tricks</A><BR>
+</P>
+
+<P><A HREF="#as400.top">Back to chart</A></P>
+
+
+
+<H4><A NAME="intel">Intel Shiva LANRover / Net Structure</A></H4>
+
+<UL>
+<LI>Intel Shiva LANRover is now known as Intel Net Structure.</LI>
+<LI>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/01/msg00298.html">
+Shiva seems to have two modes: IPsec or the proprietary
+"Shiva Tunnel".</A>
+Of course, FreeS/WAN will only create IPsec tunnels.
+</LI>
+
+<LI>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/02/msg00293.html">
+AH may not work for Shiva-FreeS/WAN.</A>
+That's OK, since FreeS/WAN has phased out the use of AH.
+</LI>
+</UL>
+
+<P>
+<A HREF="http://snowcrash.tdyc.com/freeswan/">
+Snowcrash's configs (PSK)</A><BR>
+
+<A HREF="http://www.opus1.com/vpn/index.html">
+Old configs from an interop (PSK)</A><BR>
+
+<A HREF="http://lists.freeswan.org/pipermail/users/2001-October/003831.html">
+The day Shiva tickled a Pluto bug (PSK)</A><BR>
+
+&nbsp;&nbsp;&nbsp;&nbsp;
+<A HREF="http://lists.freeswan.org/pipermail/users/2001-October/004270.html">
+Follow up: success!</A>
+</P>
+
+<P><A HREF="#intel.top">Back to chart</A></P>
+
+
+
+<H4><A NAME="lancom">LanCom (formerly ELSA)</A></H4>
+
+<UL>
+<LI>This router is popular in Germany.
+</UL>
+
+<P>
+Jakob Curdes successfully created a PSK connection with the LanCom 1612 in 
+August 2003.
+<!-- add ML link when it appears -->
+</P>
+
+<P><A HREF="#lancom.top">Back to chart</A></P>
+
+
+
+<H4><A NAME="linksys">Linksys</A></H4>
+
+<UL>
+<LI>Linksys may be used as an IPsec tunnel endpoint, <STRONG>OR</STRONG>
+as a router in "IPsec passthrough" mode, so that the IPsec tunnel 
+passes through the Linksys.
+</LI>
+</UL>
+
+<H5>As tunnel endpoint</H5>
+<P>
+<A HREF="http://www.freeswan.ca/docs/BEFVP41/">
+Ken Bantoft's instructions (Road Warrior with PSK)</A><BR>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-February/007814.html">
+Nate Carlson's caveats</A>
+</P>
+
+<H5>In IPsec passthrough mode</H5>
+<P>
+<A HREF="http://www-ec.njit.edu/~rxt1077/Howto.txt">
+Sample HOWTO through a Linksys Router</A><BR>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2002/02/msg00114.html">
+Nadeem Hasan's configs</A><BR>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2002/02/msg00180.html">
+Brock Nanson's tips</A><BR>
+</P>
+
+<P><A HREF="#linksys.top">Back to chart</A></P>
+
+
+<H4><A NAME="lucent">Lucent</A></H4>
+
+<P>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-May/010976.html">
+Partial success report; see also the next message in thread</A>
+</P>
+<!-- section done -->
+
+<P><A HREF="#lucent.top">Back to chart</A></P>
+
+
+<H4><A NAME="netasq">Netasq</A></H4>
+
+<P>
+<A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+French page with configs (X.509)</A>
+
+</P>
+<!-- section done -->
+
+<P><A HREF="#netasq.top">Back to chart</A></P>
+
+
+
+<H4><A NAME="netcelo">Netcelo</A></H4>
+
+<P>
+<A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+French page with configs (X.509)</A>
+
+<!-- section done -->
+
+</P>
+
+<P><A HREF="#netcelo.top">Back to chart</A></P>
+
+
+
+<H4><A NAME="netgear">Netgear fvs318</A></H4>
+
+<UL>
+<LI>With a recent Linux FreeS/WAN, you will require the latest 
+(12/2002) Netgear firmware, which supports Diffie-Hellman (DH) group 2.
+For security reasons, we phased out DH 1 after Linux FreeS/WAN 1.5.
+</LI>
+<LI>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-June/011833.html">
+This message</A> reports the incompatibility between Linux FreeS/WAN 1.6+
+and Netgear fvs318 without the firmware upgrade.
+</LI>
+<LI>We believe Linux FreeS/WAN 1.5 and earlier will interoperate with 
+any NetGear firmware.
+</LI>
+</UL>
+
+<P>
+<A HREF="http://lists.freeswan.org/pipermail/users/2003-February/017891.html">
+John Morris' setup (PSK)</A>
+</P>
+
+<P><A HREF="#netgear.top">Back to chart</A></P>
+
+
+
+<H4><A NAME="netscreen">Netscreen 100 or 5xp</A></H4>
+
+<P>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-August/013409.html">
+Errol Neal's settings (PSK)</A><BR>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-October/015265.html">
+Corey Rogers' configs (PSK, no PFS)</A><BR>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-August/013051.html">
+Jordan Share's configs (PSK, 2 subnets, through static NAT)</A><BR>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/08/msg00404.html">
+Set src proxy_id to your protected subnet/mask</A><BR>
+
+<A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+French page with ipsec.conf, Netscreen screen shots (X.509, may
+need to revert to PSK...)</A>
+
+</P>
+<P>
+<A HREF="http://archives.neohapsis.com/archives/sf/linux/2001-q2/0123.html">
+A report of a company using Netscreen with FreeS/WAN on a large scale
+(FreeS/WAN road warriors?)</A>
+</P>
+
+<P><A HREF="#netscreen.top">Back to chart</A></P>
+
+
+
+<H4><A NAME="nortel">Nortel Contivity</A></H4>
+
+<UL>
+<LI>
+Nortel supports IPsec-over-UDP NAT traversal.
+</LI>
+
+<LI>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/02/msg00417.html">
+Some older versions of Contivity and FreeS/WAN will not communicate.</A>
+</LI>
+
+<LI>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-May/010924.html">
+FreeS/WAN cannot be used as a "client" to a Nortel Contivity server,
+but can be used as a branch-office tunnel.</A>
+</LI>
+
+<!--  Probably obsoleted by Ken's post
+<LI>
+(Matthias siebler from old interop)
+At one point you could not configure Nortel-FreeS/WAN tunnels as 
+"Client Tunnels" since FreeS/WAN does not support Aggressive Mode.
+Current status of this problem: unknown.
+<LI>
+<A HREF="http://lists.freeswan.org/pipermail/users/2001-November/004612.html">
+How do we map group and user passwords onto the data that FreeS/WAN wants?
+</A>
+</LI>
+-->
+
+<LI>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-October/015455.html">
+Contivity does not send Distinguished Names in the order FS wants them (X.509).
+</A>
+</LI>
+
+<LI>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/03/msg00137.html">
+Connections may time out after 30-40 minutes idle.</A>
+</LI>
+
+</UL>
+
+<P>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/03/msg00137.html">
+JJ Streicher-Bremer's mini HOWTO for old & new software. (PSK with two subnets)
+</A><BR>
+<A HREF="http://www.hsc.fr/ressources/ipsec/ipsec2001/#config">
+French page with configs (X.509)</A>. This succeeds using the above X.509 tip.
+</P>
+
+<!-- I could do more searching but this is a solid start. -->
+
+<P><A HREF="#nortel.top">Back to chart</A></P>
+
+
+<H4><A NAME="radguard">Radguard</A></H4>
+
+<P>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/05/msg00009.html">
+Marko Hausalo's configs (PSK).</A> Note: These do create a connection,
+as you can see by "IPsec SA established".<BR>
+
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-October/???.html">
+Claudia Schmeing's comments</A>
+</P>
+
+<P><A HREF="#radguard.top">Back to chart</A></P>
+
+
+<H4><A NAME="raptor">Raptor (NT or Solaris)</A></H4>
+
+<P>
+
+<UL>
+<LI>Now known as Symantec Enterprise Firewall.</LI>
+<LI>The Raptor does not normally come with X.509, but this may be available as
+an add-on.</LI>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2002-May/010256.html">
+Raptor requires alphanumberic PSK values, whereas FreeS/WAN uses hex.</A>
+</LI>
+<LI>Raptor's tunnel endpoint may be a host, subnet or group of subnets
+(see 
+<A HREF="http://lists.freeswan.org/pipermail/design/2001-November/001295.html">
+this message</A>
+). FreeS/WAN cannot handle the group of subnets; you
+must create separate connections for each in order to interoperate.</LI>
+<LI>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-May/010113.html">
+Some versions of Raptor accept only single DES.
+</A>
+According to this German message,
+<A HREF="http://radawana.cg.tuwien.ac.at/mail-archives/lll/200012/msg00065.html">
+the Raptor Mobile Client demo offers single DES only.</A>
+</LI>
+</UL>
+
+<P>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-January/006935.html">
+Peter Mazinger's settings (PSK)</A><BR>
+
+<A HREF="http://lists.freeswan.org/pipermail/users/2001-November/005522.html">
+Peter Gerland's configs (PSK)</A><BR>
+
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/07/msg00597.html">
+Charles Griebel's configs (PSK).</A><BR>
+
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-July/012275.html">
+Lumir Srch's tips (PSK)
+</A>
+</P>
+
+<P>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/05/msg00214.html">
+John Hardy's configs (Manual)</A><BR>
+
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/01/msg00236.html">
+Older Raptors want 3DES keys in 3 parts (Manual).</A><BR>
+
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/06/msg00480.html">
+Different keys for each direction? (Manual)</A><BR>
+
+</P>
+
+<P><A HREF="#raptor.top">Back to chart</A></P>
+
+
+
+<H4><A NAME="redcreek">Redcreek Ravlin</A></H4>
+
+<UL>
+<LI>Known issue #1: The Ravlin expects a quick mode renegotiation right
+after every Main Mode negotiation.
+</LI>
+<LI>
+Known issue #2: The Ravlin tries to negotiate a zero
+connection lifetime, which it takes to mean "infinite". 
+<A HREF="http://www.bear-cave.org.uk/linux/ravlin/">Jim Hague's patch</A> 
+addresses both issues.
+</LI>
+<LI>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/03/msg00191.html">
+Interop works with Ravlin Firmware > 3.33. Includes tips (PSK).</A>
+</LI>
+</UL>
+
+<P><A HREF="#redcreek.top">Back to chart</A></P>
+
+
+
+<H4><A NAME="sonicwall">SonicWall</A></H4>
+
+<UL>
+<LI><A HREF="http://lists.freeswan.org/pipermail/users/2001-June/000998.html">
+Sonicwall cannot be used for Road Warrior setups</A></LI>
+<LI>
+At one point, <A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/05/msg00217.html">
+only Sonicwall PRO supported triple DES</A>.</LI>
+<LI>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-March/008600.html">
+Older Sonicwalls (before Nov 2001) feature Diffie Hellman group 1
+only</A>.</LI>
+</UL>
+
+<P>
+<A HREF="http://www.xinit.cx/docs/freeswan.html">Paul Wouters' config (PSK)</A><BR>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/02/msg00073.html">
+Dilan Arumainathan's configuration (PSK)</A><BR>
+<A HREF="http://www.gravitas.co.uk/vpndebug">Dariush's setup... only opens
+one way (PSK)</A><BR>
+<A HREF="http://lists.freeswan.org/pipermail/users/2003-July/022302.html">
+Andreas Steffen's tips (X.509)</A><BR>
+
+</P>
+
+<P><A HREF="#sonicwall.top">Back to chart</A></P>
+
+
+
+<H4><A NAME="sun">Sun Solaris</A></H4>
+
+<UL>
+<LI>
+Solaris 8+ has a native (in kernel) IPsec implementation.
+</LI>
+<LI>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-May/010503.html">
+Solaris does not seem to support tunnel mode, but you can make
+IP-in-IP tunnels instead, like this.</A>
+</LI>
+</UL>
+<P>
+
+<A HREF="http://lists.freeswan.org/pipermail/users/2003-June/022216.html">Reports of some successful interops</A> from a fellow @sun.com.
+See also <A HREF="http://lists.freeswan.org/pipermail/users/2003-July/022247.html">these follow up posts</A>.<BR>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/03/msg00332.html">
+Aleks Shenkman's configs (Manual in transport mode)
+</A><BR>
+<!--sparc 64 stuff goes where?-->
+</P>
+
+<P><A HREF="#solaris.top">Back to chart</A></P>
+
+
+
+<H4><A NAME="symantec">Symantec</A></H4>
+
+<UL>
+<LI>The Raptor, covered <A HREF="#raptor">above</A>, is now known as
+Symantec Enterprise Firewall.</LI>
+<LI>Symantec's "distinguished name" is a KEY_ID. See Andreas Steffen's post,
+below.</LI>
+</UL>
+
+<P><A HREF="http://lists.freeswan.org/pipermail/users/2002-April/009037.html">
+Andreas Steffen's configs for Symantec 200R (PSK)</A>
+</P>
+
+<P><A HREF="#symantec.top">Back to chart</A></P>
+
+
+
+
+<H4><A NAME="watchguard">Watchguard Firebox</A></H4>
+
+<UL>
+<LI>Automatic keying works with WatchGuard 5.0+ only.</LI>
+<LI>Seen to interoperate with WatchGuard 1000, II, III; firmware v. 5, 6..</LI>
+<LI>For manual keying, Watchguard's Policy Manager expects SPI numbers and
+encryption and authentication keys in decimal (not hex).</LI>
+</UL>
+
+<P>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-July/012595.html">
+WatchGuard's HOWTO (PSK)</A><BR>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-August/013342.html">
+Ronald C. Riviera's Settings (PSK)</A><BR>
+<A HREF="http://lists.freeswan.org/archives/users/2003-October/msg00179.html">
+Walter Wickersham's Notes (PSK)</A><BR>
+
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-October/015587.html">
+Max Enders' Configs (Manual)</A>
+</P>
+
+<P>
+<A HREF="http://lists.freeswan.org/pipermail/users/2002-April/009404.html">
+Old known issue with auto keying</A><BR>
+
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/02/msg00124.html">
+Tips on key generation and format (Manual)</A><BR>
+</P>
+
+<P><A HREF="#watchguard.top">Back to chart</A></P>
+
+
+
+<H4><A NAME="xedia">Xedia Access Point/QVPN</A></H4>
+
+<P>
+<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2001/12/msg00520.html">
+Hybrid IPsec/L2TP connection settings (X.509)
+</A><BR>
+<A HREF="http://www.sandelman.ottawa.on.ca/ipsec/1999/08/msg00140.html">
+  Xedia's LAN-LAN links don't use multiple tunnels
+</A><BR>
+&nbsp;&nbsp;&nbsp;&nbsp;
+<A HREF="http://www.sandelman.ottawa.on.ca/ipsec/1999/08/msg00140.html">
+  That explanation, continued
+</A>
+</P>
+
+<P><A HREF="#xedia.top">Back to chart</A></P>
+
+
+
+<H4><A NAME="zyxel">Zyxel</A></H4>
+
+<UL>
+<LI>The Zyxel Zywall is a rebranded SSH Sentinel box. See also our section
+on <A HREF="#ssh">SSH</A>.</LI>
+<LI>There seems to be a problem with keeping this connection alive. This is 
+caused at the Zyxel end. See this brief
+<A HREF="http://lists.freeswan.org/archives/users/2003-October/msg00141.html">
+discussion and solution.
+</A>
+</LI>
+</UL>                                                                                
+<P>
+<A HREF="http://www.zyxel.com/support/supportnote/zywall/app/zw_freeswan.htm">
+Zyxel's Zywall to FreeS/WAN instructions (PSK)</A><BR>
+<A HREF="http://www.zyxel.com/support/supportnote/p652/app/zw_freeswan.htm">
+Zyxel's Prestige to FreeS/WAN instructions (PSK)</A>. Note: not all Prestige 
+versions include VPN software.<BR>
+
+<A HREF="http://www.lancry.net/techdocs/freeswan-zyxel.txt">Fabrice Cahen's 
+ HOWTO (PSK)</A><BR>
+&nbsp;&nbsp;&nbsp;&nbsp;
+</P>
+                                                                                
+<P><A HREF="#zyxel.top">Back to chart</A></P>
+
+
+
+<!-- SAMPLE ENTRY
+
+<H4><A NAME="timestep">Timestep</A></H4>
+
+<P>Text goes here.
+</P>
+
+-->
+</BODY></HTML>
+
diff --git a/doc/src/intro.html b/doc/src/intro.html
new file mode 100644
index 000000000..09c352c00
--- /dev/null
+++ b/doc/src/intro.html
@@ -0,0 +1,887 @@
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>Introduction to FreeS/WAN</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, FreeSWAN, introduction">
+  <!--
+
+  Written by Sandy Harris for the Linux FreeS/WAN project
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: intro.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+
+<body>
+<h1><a name="intro">Introduction</a></h1>
+
+<p>This section gives an overview of:</p>
+<ul>
+  <li>what IP Security (IPsec) does</li>
+  <li>how IPsec works</li>
+  <li>why we are implementing it for Linux</li>
+  <li>how this implementation works</li>
+</ul>
+
+<p>This section is intended to cover only the essentials, <em>things you
+should know before trying to use FreeS/WAN.</em></p>
+
+<p>For more detailed background information, see the <a
+href="politics.html#politics">history and politics</a> and 
+<a href="ipsec.html#ipsec.detail">IPsec protocols</a> sections.</p>
+
+<h2><a name="ipsec.intro">IPsec, Security for the Internet Protocol</a></h2>
+
+<p>FreeS/WAN is a Linux implementation of the IPsec (IP security) protocols.
+IPsec provides <a href="glossary.html#encryption">encryption</a> and <a
+href="glossary.html#authentication">authentication</a> services at the IP
+(Internet Protocol) level of the network protocol stack.</p>
+
+<p>Working at this level, IPsec can protect any traffic carried over IP,
+unlike other encryption which generally protects only a particular
+higher-level protocol -- <a href="glossary.html#PGP">PGP</a> for mail, <a
+href="glossary.html#SSH">SSH</a> for remote login, <a
+href="glossary.html#SSL">SSL</a> for web work, and so on. This approach has
+both considerable advantages and some limitations. For discussion, see our <a
+href="ipsec.html#others">IPsec section</a></p>
+
+<p>IPsec can be used on any machine which does IP networking. Dedicated IPsec
+gateway machines can be installed wherever required to protect traffic. IPsec
+can also run on routers, on firewall machines, on various application
+servers, and on end-user desktop or laptop machines.</p>
+
+<p>Three protocols are used</p>
+<ul>
+  <li><a href="glossary.html#AH">AH</a> (Authentication Header) provides a
+    packet-level authentication service</li>
+  <li><a href="glossary.html#ESP">ESP</a> (Encapsulating Security Payload)
+    provides encryption plus authentication</li>
+  <li><a href="glossary.html#IKE">IKE</a> (Internet Key Exchange) negotiates
+    connection parameters, including keys, for the other two</li>
+</ul>
+
+<p>Our implementation has three main parts:</p>
+<ul>
+  <li><a href="glossary.html#KLIPS">KLIPS</a> (kernel IPsec) implements AH,
+    ESP, and packet handling within the kernel</li>
+  <li><a href="glossary.html#Pluto">Pluto</a> (an IKE daemon) implements IKE,
+    negotiating connections with other systems</li>
+  <li>various scripts provide an adminstrator's interface to the
+  machinery</li>
+</ul>
+
+<p>IPsec is optional for the current (version 4) Internet Protocol. FreeS/WAN
+adds IPsec to the Linux IPv4 network stack. Implementations of <a
+href="glossary.html#ipv6.gloss">IP version 6</a> are required to include
+IPsec. Work toward integrating FreeS/WAN into the Linux IPv6 stack has <a
+href="compat.html#ipv6">started</a>.</p>
+
+<p>For more information on IPsec, see our 
+<a href="ipsec.html#ipsec.detail">IPsec protocols</a> section, 
+our collection of <a href="web.html#ipsec.link">IPsec
+links</a> or the <a href="rfc.html#RFC">RFCs</a> which are the official
+definitions of these protocols.</p>
+
+<h3><a name="intro.interop">Interoperating with other IPsec
+implementations</a></h3>
+
+<p>IPsec is designed to let different implementations work together. We
+provide:</p>
+<ul>
+  <li>a <a href="web.html#implement">list</a> of some other
+  implementations</li>
+  <li>information on <a href="interop.html#interop">using FreeS/WAN 
+  with other implementations</a></li>
+</ul>
+
+<p>The VPN Consortium fosters cooperation among implementers and
+interoperability among implementations. Their <a
+href="http://www.vpnc.org/">web site</a> has much more information.</p>
+
+<h3><a name="advantages">Advantages of IPsec</a></h3>
+
+<p>IPsec has a number of security advantages. Here are some independently 
+written articles which discuss these:</p>
+
+<P>
+<A HREF="http://www.sans.org/rr/">SANS institute papers</A>. See the section
+on Encryption &amp;VPNs.
+<BR>
+<A HREF="http://www.cisco.com/en/US/netsol/ns110/ns170/ns171/ns128/networking_solutions_white_papers_list.html">Cisco's 
+white papers on "Networking Solutions"</A>.
+<BR>
+<A HREF="http://iscs.sourceforge.net/HowWhyBrief/HowWhyBrief.html">
+Advantages of ISCS (Linux Integrated Secure Communications System; 
+includes FreeS/WAN and other software)</A>.
+
+</P>
+
+
+<h3><a name="applications">Applications of IPsec</a></h3>
+
+<p>Because IPsec operates at the network layer, it is remarkably flexible and
+can be used to secure nearly any type of Internet traffic. Two applications,
+however, are extremely widespread:</p>
+<ul>
+  <li>a <a href="glossary.html#VPN">Virtual Private Network</a>, or VPN,
+    allows multiple sites to communicate securely over an insecure Internet
+    by encrypting all communication between the sites.</li>
+  <li>"Road Warriors" connect to the office from home, or perhaps from a
+    hotel somewhere</li>
+</ul>
+
+<p>There is enough opportunity in these applications that vendors are
+flocking to them. IPsec is being built into routers, into firewall products,
+and into major operating systems, primarily to support these applications.
+See our <a href="web.html#implement">list</a> of implementations for
+details.</p>
+
+<p>We support both of those applications, and various less common IPsec
+applications as well, but we also add one of our own:</p>
+<ul>
+  <li>opportunistic encryption, the ability to set up FreeS/WAN gateways so
+    that any two of them can encrypt to each other, and will do so whenever
+    packets pass between them.</li>
+</ul>
+
+<p>This is an extension we are adding to the protocols. FreeS/WAN is the
+first prototype implementation, though we hope other IPsec implementations
+will adopt the technique once we demonstrate it. See <a href="#goals">project
+goals</a> below for why we think this is important.</p>
+
+<p>A somewhat more detailed description of each of these applications is
+below. Our <a href="quickstart.html#quick_guide">quickstart</a> section will 
+show you how to build each of them.</p>
+
+<h4><a name="makeVPN">Using secure tunnels to create a VPN</a></h4>
+
+<p>A VPN, or <strong>V</strong>irtual <strong>P</strong>rivate
+<strong>N</strong>etwork lets two networks communicate securely when the only
+connection between them is over a third network which they do not trust.</p>
+
+<p>The method is to put a security gateway machine between each of the
+communicating networks and the untrusted network. The gateway machines
+encrypt packets entering the untrusted net and decrypt packets leaving it,
+creating a secure tunnel through it.</p>
+
+<p>If the cryptography is strong, the implementation is careful, and the
+administration of the gateways is competent, then one can reasonably trust
+the security of the tunnel. The two networks then behave like a single large
+private network, some of whose links are encrypted tunnels through untrusted
+nets.</p>
+
+<p>Actual VPNs are often more complex. One organisation may have fifty branch
+offices, plus some suppliers and clients, with whom it needs to communicate
+securely. Another might have 5,000 stores, or 50,000 point-of-sale devices.
+The untrusted network need not be the Internet. All the same issues arise on
+a corporate or institutional network whenever two departments want to
+communicate privately with each other.</p>
+
+<p>Administratively, the nice thing about many VPN setups is that large parts
+of them are static. You know the IP addresses of most of the machines
+involved. More important, you know they will not change on you. This
+simplifies some of the admin work. For cases where the addresses do change,
+see the next section.</p>
+
+<h4><a name="road.intro">Road Warriors</a></h4>
+
+<p>The prototypical "Road Warrior" is a traveller connecting to home base
+from a laptop machine. Administratively, most of the same problems arise for
+a telecommuter connecting from home to the office, especially if the
+telecommuter does not have a static IP address.</p>
+
+<p>For purposes of this document:</p>
+<ul>
+  <li>anyone with a dynamic IP address is a "Road Warrior".</li>
+  <li>any machine doing IPsec processing is a "gateway". Think of the
+    single-user road warrior machine as a gateway with a degenerate subnet
+    (one machine, itself) behind it.</li>
+</ul>
+
+<p>These require somewhat different setup than VPN gateways with static
+addresses and with client systems behind them, but are basically not
+problematic.</p>
+
+<p>There are some difficulties which appear for some road warrior
+connections:</p>
+<ul>
+  <li>Road Wariors who get their addresses via DHCP may have a problem.
+    FreeS/WAN can quite happily build and use a tunnel to such an address,
+    but when the DHCP lease expires, FreeS/WAN does not know that. The tunnel
+    fails, and the only recovery method is to tear it down and re-build
+  it.</li>
+  <li>If <a href="glossary.html#NAT.gloss">Network Address Translation</a>
+    (NAT) is applied between the two IPsec Gateways, this breaks IPsec. IPsec
+    authenticates packets on an end-to-end basis, to ensure they are not
+    altered en route. NAT rewrites packets as they go by. See our <a
+    href="firewall.html#NAT">firewalls</a> document for details.</li>
+</ul>
+
+<p>In most situations, however, FreeS/WAN supports road warrior connections
+just fine.</p>
+
+<h4><a name="opp.intro">Opportunistic encryption</a></h4>
+
+<p>One of the reasons we are working on FreeS/WAN is that it gives us the
+opportunity to add what we call opportuntistic encryption. This means that
+any two FreeS/WAN gateways will be able to encrypt their traffic, even if the
+two gateway administrators have had no prior contact and neither system has
+any preset information about the other.</p>
+
+<p>Both systems pick up the authentication information they need from the <a
+href="glossary.html#DNS">DNS</a> (domain name service), the service they
+already use to look up IP addresses. Of course the administrators must put
+that information in the DNS, and must set up their gateways with
+opportunistic encryption enabled. Once that is done, everything is automatic.
+The gateways look for opportunities to encrypt, and encrypt whatever they
+can. Whether they also accept unencrypted communication is a policy decision
+the administrator can make.</p>
+
+<p>This technique can give two large payoffs:</p>
+<ul>
+  <li>It reduces the administrative overhead for IPsec enormously. You
+    configure your gateway and thereafter everything is automatic. The need
+    to configure the system on a per-tunnel basis disappears. Of course,
+    FreeS/WAN allows specifically configured tunnels to co-exist with
+    opportunistic encryption, but we hope to make them unnecessary in most
+    cases.</li>
+  <li>It moves us toward a more secure Internet, allowing users to create an
+    environment where message privacy is the default. All messages can be
+    encrypted, provided the other end is willing to co-operate. See our <a
+    href="politics.html#politics">history and politics of cryptography</a> 
+    section for discussion of why we think this is needed.</li>
+</ul>
+
+<p>Opportunistic encryption is not (yet?) a standard part of the IPsec
+protocols, but an extension we are proposing and demonstrating. For details
+of our design, see <a href="#applied">links</a> below.</p>
+
+<p>Only one current product we know of implements a form of opportunistic
+encryption. <a href="web.html#ssmail">Secure sendmail</a> will automatically
+encrypt server-to-server mail transfers whenever possible.</p>
+
+<h3><a name="types">The need to authenticate gateways</a></h3>
+
+<p>A complication, which applies to any type of connection -- VPN, Road
+Warrior or opportunistic -- is that a secure connection cannot be created
+magically. <em>There must be some mechanism which enables the gateways to
+reliably identify each other.</em> Without this, they cannot sensibly trust
+each other and cannot create a genuinely secure link.</p>
+
+<p>Any link they do create without some form of <a
+href="glossary.html#authentication">authentication</a> will be vulnerable to
+a <a href="glossary.html#middle">man-in-the-middle attack</a>. If <a
+href="glossary.html#alicebob">Alice and Bob</a> are the people creating the
+connection, a villian who can re-route or intercept the packets can pose as
+Alice while talking to Bob and pose as Bob while talking to Alice. Alice and
+Bob then both talk to the man in the middle, thinking they are talking to
+each other, and the villain gets everything sent on the bogus "secure"
+connection.</p>
+
+<p>There are two ways to build links securely, both of which exclude the
+man-in-the middle:</p>
+<ul>
+  <li>with <strong>manual keying</strong>, Alice and Bob share a secret key
+    (which must be transmitted securely, perhaps in a note or via PGP or SSH)
+    to encrypt their messages. For FreeS/WAN, such keys are stored in the <a
+    href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a> file. Of course, if
+    an enemy gets the key, all is lost.</li>
+  <li>with <strong>automatic keying</strong>, the two systems authenticate
+    each other and negotiate their own secret keys. The keys are
+    automatically changed periodically.</li>
+</ul>
+
+<p>Automatic keying is much more secure, since if an enemy gets one key only
+messages between the previous re-keying and the next are exposed. It is
+therefore the usual mode of operation for most IPsec deployment, and the mode
+we use in our setup examples. FreeS/WAN does support manual keying for
+special circumstanes. See this <a
+href="adv_config.html#prodman">section</a>.</p>
+
+<p>For automatic keying, the two systems must authenticate each other during
+the negotiations. There is a choice of methods for this:</p>
+<ul>
+  <li>a <strong>shared secret</strong> provides authentication. If Alice and
+    Bob are the only ones who know a secret and Alice recives a message which
+    could not have been created without that secret, then Alice can safely
+    believe the message came from Bob.</li>
+  <li>a <a href="glossary.html#public">public key</a> can also provide
+    authentication. If Alice receives a message signed with Bob's private key
+    (which of course only he should know) and she has a trustworthy copy of
+    his public key (so that she can verify the signature), then she can
+    safely believe the message came from Bob.</li>
+</ul>
+
+<p>Public key techniques are much preferable, for reasons discussed <a
+href="config.html#choose">later</a>, and will be used in all our setup
+examples. FreeS/WAN does also support auto-keying with shared secret
+authentication. See this <a
+href="adv_config.html#prodsecrets">section</a>.</p>
+
+<h2><a name="project">The FreeS/WAN project</a></h2>
+
+<p>For complete information on the project, see our web site, <a
+href="http://liberty.freeswan.org">freeswan.org</a>.</p>
+
+<p>In summary, we are implementing the <a
+href="glossary.html#IPsec">IPsec</a> protocols for Linux and extending them
+to do <a href="glossary.html#carpediem">opportunistic encryption</a>.</p>
+
+<h3><a name="goals">Project goals</a></h3>
+
+<p>Our overall goal in FreeS/WAN is to make the Internet more secure and more
+private.</p>
+
+<p>Our IPsec implementation supports VPNs and Road Warriors of course. Those
+are important applications. Many users will want FreeS/WAN to build corporate
+VPNs or to provide secure remote access.</p>
+
+<p>However, our goals in building it go beyond that. We are trying to help
+<strong>build security into the fabric of the Internet</strong> so that
+anyone who choses to communicate securely can do so, as easily as they can do
+anything else on the net.</p>
+
+<p>More detailed objectives are:</p>
+<ul>
+  <li>extend IPsec to do <a href="glossary.html#carpediem">opportunistic
+    encryption</a> so that
+    <ul>
+      <li>any two systems can secure their communications without a
+        pre-arranged connection</li>
+      <li><strong>secure connections can be the default</strong>, falling
+        back to unencrypted connections only if:
+        <ul>
+          <li><em>both</em> the partner is not set up to co-operate on
+            securing the connection</li>
+          <li><em>and</em> your policy allows insecure connections</li>
+        </ul>
+      </li>
+      <li>a significant fraction of all Internet traffic is encrypted</li>
+      <li>wholesale monitoring of the net (<a
+        href="politics.html#intro.poli">examples</a>) becomes difficult or
+        impossible</li>
+    </ul>
+  </li>
+  <li>help make IPsec widespread by providing an implementation with no
+    restrictions:
+    <ul>
+      <li>freely available in source code under the <a
+        href="glossary.html#GPL">GNU General Public License</a></li>
+      <li>running on a range of readily available hardware</li>
+      <li>not subject to US or other nations' <a
+        href="politics.html#exlaw">export restrictions</a>.<br>
+        Note that in order to avoid <em>even the appearance</em> of being
+        subject to those laws, the project cannot accept software
+        contributions -- <em>not even one-line bug fixes</em> -- from US
+        residents or citizens.</li>
+    </ul>
+  </li>
+  <li>provide a high-quality IPsec implementation for Linux
+    <ul>
+      <li>portable to all CPUs Linux supports: <a
+        href="compat.html#CPUs">(current list)</a></li>
+      <li>interoperable with other IPsec implementations: <a
+        href="interop.html#interop">(current list)</a></li>
+    </ul>
+  </li>
+</ul>
+
+<p>If we can get opportunistic encryption implemented and widely deployed,
+then it becomes impossible for even huge well-funded agencies to monitor the
+net.</p>
+
+<p>See also our section on <a href="politics.html#politics">history and 
+politics</a> of cryptography, which includes our project leader's <a
+href="politics.html#gilmore">rationale</a> for starting the project.</p>
+
+<h3><a name="staff">Project team</a></h3>
+
+<p>Two of the team are from the US and can therefore contribute no code:</p>
+<ul>
+  <li>John Gilmore: founder and policy-maker (<a
+    href="http://www.toad.com/gnu/">home page</a>)</li>
+  <li>Hugh Daniel: project manager, Most Demented Tester, and occasionally
+    Pointy-Haired Boss</li>
+</ul>
+
+<p>The rest of the team are Canadians, working in Canada. (<a
+href="politics.html#status">Why Canada?</a>)</p>
+<ul>
+  <li>Hugh Redelmeier: <a href="glossary.html#Pluto">Pluto daemon</a>
+    programmer</li>
+  <li>Richard Guy Briggs: <a href="glossary.html#KLIPS">KLIPS</a>
+  programmer</li>
+  <li>Michael Richardson: hacker without portfolio</li>
+  <li>Claudia Schmeing: documentation</li>
+  <li>Sam Sgro: technical support via the <a href="mail.html#lists">mailing
+    lists</a></li>
+</ul>
+
+<p>The project is funded by civil libertarians who consider our goals
+worthwhile. Most of the team are paid for this work.</p>
+
+<p>People outside this core team have made substantial contributions. See</p>
+<ul>
+  <li>our <a href="../CREDITS">CREDITS</a> file</li>
+  <li>the <a href="web.html#patch">patches and add-ons</a> section of our web
+    references file</li>
+  <li>lists below of user-written <a href="#howto">HowTos</a> and <a
+    href="#applied">other papers</a></li>
+</ul>
+
+<p>Additional contributions are welcome. See the <a
+href="faq.html#contrib.faq">FAQ</a> for details.</p>
+
+<h2><a name="products">Products containing FreeS/WAN</a></h2>
+
+<p>Unfortunately the <a href="politics.html#exlaw">export laws</a> of some
+countries restrict the distribution of strong cryptography. FreeS/WAN is
+therefore not in the standard Linux kernel and not in all CD or web
+distributions.</p>
+
+<p>FreeS/WAN is, however, quite widely used. Products we know of that use it
+are listed below. We would appreciate hearing, via the <a
+href="mail.html#lists">mailing lists</a>, of any we don't know of.</p>
+
+<h3><a name="distwith">Full Linux distributions</a></h3>
+
+<p>FreeS/WAN is included in various general-purpose Linux distributions,
+mostly from countries (shown in brackets) with more sensible laws:</p>
+<ul>
+  <li><a href="http://www.suse.com/">SuSE Linux</a> (Germany)</li>
+  <li><a href="http://www.conectiva.com">Conectiva</a> (Brazil)</li>
+  <li><a href="http://www.linux-mandrake.com/en/">Mandrake</a> (France)</li>
+  <li><a href="http://www.debian.org">Debian</a></li>
+  <li>the <a href="http://www.pld.org.pl/">Polish(ed) Linux Distribution</a>
+    (Poland)</li>
+  <li><a>Best Linux</a> (Finland)</li>
+</ul>
+
+<p>For distributions which do not include FreeS/WAN and are not Redhat (which
+we develop and test on), there is additional information in our <a
+href="compat.html#otherdist">compatibility</a> section.</p>
+
+<p>The server edition of <a href="http://www.corel.com">Corel</a> Linux
+(Canada) also had FreeS/WAN, but Corel have dropped that product line.</p>
+
+<h3><a name="kernel_dist">Linux kernel distributions</a></h3>
+
+<ul>
+<li><a href="http://sourceforge.net/projects/wolk/">Working Overloaded Linux Kernel (WOLK)</a></li>
+</ul>
+
+
+<h3><a name="office_dist">Office server distributions</a></h3>
+
+<p>FreeS/WAN is also included in several distributions aimed at the market
+for turnkey business servers:</p>
+<ul>
+  <li><a href="http://www.e-smith.com/">e-Smith</a> (Canada), which has
+    recently been acquired and become the Network Server Solutions group of
+    <a href="http://www.mitel.com/">Mitel Networks</a> (Canada)</li>
+  <li><a href="http://www.clarkconnect.org/">ClarkConnect</a> from Point Clark Networks (Canada)</li>
+  <li><a href="http://www.trustix.net/">Trustix Secure Linux</a> (Norway)</li>
+   
+</ul>
+
+<h3><a name="fw_dist">Firewall distributions</a></h3>
+
+<p>Several distributions intended for firewall and router applications
+include FreeS/WAN:</p>
+<ul>
+  <li>The <a href="http://www.linuxrouter.org/">Linux Router Project</a>
+    produces a Linux distribution that will boot from a single floppy. The <a
+    href="http://leaf.sourceforge.net">LEAF</a> firewall project provides
+    several different LRP-based firewall packages. At least one of them,
+    Charles Steinkuehler's Dachstein, includes FreeS/WAN with X.509
+  patches.</li>
+  <li>there are several distributions bootable directly from CD-ROM, usable
+    on a machine without hard disk.
+    <ul>
+      <li>Dachstein (see above) can be used this way</li>
+      <li><a href="http://www.gibraltar.at/">Gibraltar</a> is based on Debian
+        GNU/Linux.</li>
+      <li>at time of writing, <a href="www.xiloo.com">Xiloo</a> is available
+        only in Chinese. An English version is expected.</li>
+    </ul>
+  </li>
+  <li><a href="http://www.astaro.com/products/index.html">Astaro Security
+    Linux</a> includes FreeS/WAN. It has some web-based tools for managing
+    the firewall that include FreeS/WAN configuration management.</li>
+  <li><a href="http://www.linuxwall.de">Linuxwall</a></li>
+  <li><a href="http://www.smoothwall.org/">Smoothwall</a></li>
+  <li><a href="http://www.devil-linux.org/">Devil Linux</a></li>
+  <li>Coyote Linux has a <a
+    href="http://embedded.coyotelinux.com/wolverine/index.php">Wolverine</a>
+    firewall/VPN server</li>
+</ul>
+
+<p>There are also several sets of scripts available for managing a firewall
+which is also acting as a FreeS/WAN IPsec gateway. See this <a
+href="firewall.html#rules.pub">list</a>.</p>
+
+<h3><a name="turnkey">Firewall and VPN products</a></h3>
+
+<p>Several vendors use FreeS/WAN as the IPsec component of a turnkey firewall
+or VPN product.</p>
+
+<p>Software-only products:</p>
+<ul>
+  <li><a href="http://www.linuxmagic.com/vpn/index.html">Linux Magic</a>
+    offer a VPN/Firewall product using FreeS/WAN</li>
+  <li>The Software Group's <a
+    href="http://www.wanware.com/sentinet/">Sentinet</a> product uses
+    FreeS/WAN</li>
+  <li><a href="http://www.merilus.com">Merilus</a> use FreeS/WAN in their
+    Gateway Guardian firewall product</li>
+</ul>
+
+<p>Products that include the hardware:</p>
+<ul>
+  <li>The <a href="http://www.lasat.com">LASAT SafePipe[tm]</a> series. is an
+    IPsec box based on an embedded MIPS running Linux with FreeS/WAN and a
+    web-config front end. This company also host our freeswan.org web
+  site.</li>
+  <li>Merilus <a
+    href="http://www.merilus.com/products/fc/index.shtml">Firecard</a> is a
+    Linux firewall on a PCI card.</li>
+  <li><a href="http://www.kyzo.com/">Kyzo</a> have a "pizza box" product line
+    with various types of server, all running from flash. One of them is an
+    IPsec/PPTP VPN server</li>
+  <li><a href="http://www.pfn.com">PFN</a> use FreeS/WAN in some of their
+    products</li>
+</ul>
+
+<p><a href="www.rebel.com">Rebel.com</a>, makers of the Netwinder Linux
+machines (ARM or Crusoe based), had a product that used FreeS/WAN. The
+company is in receivership so the future of the Netwinder is at best unclear.
+<a href="web.html#patch">PKIX patches</a> for FreeS/WAN developed at Rebel
+are listed in our web links document.</p>
+
+
+<h2><a name="docs">Information sources</a></h2>
+
+<h3><a name="docformats">This HowTo, in multiple formats</a></h3>
+
+<p>FreeS/WAN documentation up to version 1.5 was available only in HTML. Now
+we ship two formats:</p>
+<ul>
+  <li>as HTML, one file for each doc section plus a global <a
+    href="toc.html">Table of Contents</a></li>
+  <li><a href="HowTo.html">one big HTML file</a> for easy searching</li>
+</ul>
+
+<p>and provide a Makefile to generate other formats if required:</p>
+<ul>
+  <li><a href="HowTo.pdf">PDF</a></li>
+  <li><a href="HowTo.ps">Postscript</a></li>
+  <li><a href="HowTo.txt">ASCII text</a></li>
+</ul>
+
+<p>The Makefile assumes the htmldoc tool is available. You can download it
+from <a href="http://www.easysw.com">Easy Software</a>.</p>
+
+<p>All formats should be available at the following websites:</p>
+<ul>
+  <li><a href="http://www.freeswan.org/doc.html">FreeS/WAN project</a></li>
+  <li><a href="http://www.linuxdoc.org">Linux Documentation Project</a></li>
+</ul>
+
+<p>The distribution tarball has only the two HTML formats.</p>
+
+<p><strong>Note:</strong> If you need the latest doc version, for example to
+see if anyone has managed to set up interoperation between FreeS/WAN and
+whatever, then you should download the current snapshot. What is on the web
+is documentation as of the last release. Snapshots have all changes I've
+checked in to date.</p>
+
+<h3><a name="rtfm">RTFM (please Read The Fine Manuals)</a></h3>
+
+<p>As with most things on any Unix-like system, most parts of Linux FreeS/WAN
+are documented in online manual pages. We provide a list of <a
+href="/mnt/floppy/manpages.html">FreeS/WAN man pages</a>, with links to HTML
+versions of them.</p>
+
+<p>The man pages describing configuration files are:</p>
+<ul>
+  <li><a href="/mnt/floppy/manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a></li>
+  <li><a
+    href="/mnt/floppy/manpage.d/ipsec.secrets.5.html">ipsec.secrets(5)</a></li>
+</ul>
+
+<p>Man pages for common commands include:</p>
+<ul>
+  <li><a href="/mnt/floppy/manpage.d/ipsec.8.html">ipsec(8)</a></li>
+  <li><a
+  href="/mnt/floppy/manpage.d/ipsec_pluto.8.html">ipsec_pluto(8)</a></li>
+  <li><a
+    href="/mnt/floppy/manpage.d/ipsec_newhostkey.8.html">ipsec_newhostkey(8)</a></li>
+  <li><a href="/mnt/floppy/manpage.d/ipsec_auto.8.html">ipsec_auto(8)</a></li>
+</ul>
+
+<p>You can read these either in HTML using the links above or with the
+<var>man(1)</var> command.</p>
+
+<p>In the event of disagreement between this HTML documentation and the man
+pages, the man pages are more likely correct since they are written by the
+implementers. Please report any such inconsistency on the <a
+href="mail.html#lists">mailing list</a>.</p>
+
+<h3><a name="text">Other documents in the distribution</a></h3>
+
+<p>Text files in the main distribution directory are README, INSTALL,
+CREDITS, CHANGES, BUGS and COPYING.</p>
+
+<p>The Libdes encryption library we use has its own documentation. You can
+find it in the library directory..</p>
+
+<h3><a name="assumptions">Background material</a></h3>
+
+<p>Throughout this documentation, I write as if the reader had at least a
+general familiarity with Linux, with Internet Protocol networking, and with
+the basic ideas of system and network security. Of course that will certainly
+not be true for all readers, and quite likely not even for a majority.</p>
+
+<p>However, I must limit amount of detail on these topics in the main text.
+For one thing, I don't understand all the details of those topics myself.
+Even if I did, trying to explain everything here would produce extremely long
+and almost completely unreadable documentation.</p>
+
+<p>If one or more of those areas is unknown territory for you, there are
+plenty of other resources you could look at:</p>
+<dl>
+  <dt>Linux</dt>
+    <dd>the <a href="http://www.linuxdoc.org">Linux Documentation Project</a>
+      or a local <a href="http://www.linux.org/groups/">Linux User Group</a>
+      and these <a href="web.html#linux.link">links</a></dd>
+  <dt>IP networks</dt>
+    <dd>Rusty Russell's <a
+      href="http://netfilter.samba.org/unreliable-guides/networking-concepts-HOWTO/index.html">Networking
+      Concepts HowTo</a> and these <a
+    href="web.html#IP.background">links</a></dd>
+  <dt>Security</dt>
+    <dd>Schneier's book <a href="biblio.html#secrets">Secrets and Lies</a>
+      and these <a href="web.html#crypto.link">links</a></dd>
+</dl>
+
+<p>Also, I do make an effort to provide some background material in these
+documents. All the basic ideas behind IPsec and FreeS/WAN are explained here.
+Explanations that do not fit in the main text, or that not everyone will
+need, are often in the <a href="glossary.html#ourgloss">glossary</a>, which is 
+the largest single file in this document set. There is also a <a
+href="background.html#background">background</a> file containing various 
+explanations too long to fit in glossary definitions. All files are heavily 
+sprinkled with links to each other and to the glossary. <strong>If some passage 
+makes no sense to you, try the links</strong>.</p>
+
+<p>For other reference material, see the <a
+href="biblio.html#biblio">bibliography</a> and our collection of <a
+href="web.html#weblinks">web links</a>.</p>
+
+<p>Of course, no doubt I get this (and other things) wrong sometimes.
+Feedback via the <a href="mail.html#lists">mailing lists</a> is welcome.</p>
+
+<h3><a name="archives">Archives of the project mailing list</a></h3>
+
+<p>Until quite recently, there was only one FreeS/WAN mailing list, and
+archives of it were:</p>
+<ul>
+  <li><a href="http://www.sandelman.ottawa.on.ca/linux-ipsec">Canada</a></li>
+  <li><a href="http://www.nexial.com">Holland</a></li>
+</ul>
+The two archives use completely different search engines. You might want to
+try both.
+
+<p>More recently we have expanded to five lists, each with its own
+archive.</p>
+
+<p><a href="mail.html#lists">More information</a> on mailing lists.</p>
+
+<h3><a name="howto">User-written HowTo information</a></h3>
+
+<p>Various user-written HowTo documents are available. The ones covering
+FreeS/WAN-to-FreeS/WAN connections are:</p>
+<ul>
+  <li>Jean-Francois Nadeau's <a href="http://jixen.tripod.com/">practical
+    configurations</a> document</li>
+  <li>Jens Zerbst's HowTo on <a href="http://dynipsec.tripod.com/">Using
+    FreeS/WAN with dynamic IP addresses</a>.</li>
+  <li>an entry in Kurt Seifried's <a
+    href="http://www.securityportal.com/lskb/kben00000013.html">Linux
+    Security Knowledge Base</a>.</li>
+  <li>a section of David Ranch's <a
+    href="http://www.ecst.csuchico.edu/~dranch/LINUX/index-linux.html#trinityos">Trinity
+    OS Guide</a></li>
+  <li>a section in David Bander's book <a href="biblio.html#bander">Linux
+    Security Toolkit</a></li>
+</ul>
+
+<p>User-wriiten HowTo material may be <strong>especially helpful if you need
+to interoperate with another IPsec implementation</strong>. We have neither
+the equipment nor the manpower to test such configurations. Users seem to be
+doing an admirable job of filling the gaps.</p>
+<ul>
+  <li>list of user-written <a href="interop.html#otherpub">interoperation
+    HowTos</a> in our interop document</li>
+</ul>
+
+<p>Check what version of FreeS/WAN user-written documents cover. The software
+is under active development and the current version may be significantly
+different from what an older document describes.</p>
+
+<h3><a name="applied">Papers on FreeS/WAN</a></h3>
+
+<p>Two design documents show team thinking on new developments:</p>
+<ul>
+  <li><a href="opportunism.spec">Opportunistic Encryption</a> by technical
+    lead Henry Spencer and Pluto programmer Hugh Redelemeier</li>
+  <li>discussion of <a
+    href="http://www.sandelman.ottawa.on.ca/SSW/freeswan/klips2req/">KLIPS
+    redesign</a></li>
+</ul>
+
+<p>Both documents are works in progress and are frequently revised. For the
+latest version, see the <a href="mail.html#lists">design mailing list</a>. Comments
+should go to that list.</p>
+
+<p>There is now an <a
+href="http://www.ietf.org/internet-drafts/draft-richardson-ipsec-opportunistic-06.txt">Internet
+Draft on Opportunistic Encryption</a> by Michael Richardson, Hugh Redelmeier
+and Henry Spencer. This is a first step toward getting the protocol
+standardised so there can be multiple implementations of it. Discussion of it
+takes place on the <a
+href="http://www.ietf.org/html.charters/ipsec-charter.html">IETF IPsec
+Working Group</a> mailing list.</p>
+
+<p>A number of papers giving further background on FreeS/WAN, or exploring
+its future or its applications, are also available:</p>
+<ul>
+  <li>Both Henry and Richard gave talks on FreeS/WAN at the 2000 <a
+    href="http://www.linuxsymposium.org">Ottawa Linux Symposium</a>.
+    <ul>
+      <li>Richard's <a
+        href="http://www.conscoop.ottawa.on.ca/rgb/freeswan/ols2k/">slides</a></li>
+      <li>Henry's paper</li>
+      <li>MP3 audio of their talks is available from the <a
+        href="http://www.linuxsymposium.org/">conference page</a></li>
+    </ul>
+  </li>
+  <li><cite>Moat: A Virtual Private Network Appliances and Services
+    Platform</cite> is a paper about large-scale (a few 100 links) use of
+    FreeS/WAN in a production application at AT&amp;T Research. It is
+    available in Postscript or PDF from co-author Steve Bellovin's <a
+    href="http://www.research.att.com/~smb/papers/index.html">papers list
+    page</a>.</li>
+  <li>One of the Moat co-authors, John Denker, has also written
+    <ul>
+      <li>a <a
+        href="http://www.av8n.com/vpn/ipsec+routing.htm">proposal</a>
+        for how future versions of FreeS/WAN might interact with routing
+        protocols</li>
+      <li>a <a
+        href="http://www.av8n.com/vpn/wishlist.htm">wishlist</a>
+        of possible new features</li>
+    </ul>
+  </li>
+  <li>Bart Trojanowski's web page has a draft design for <a
+    href="http://www.jukie.net/~bart/linux-ipsec/">hardware acceleration</a>
+    of FreeS/WAN</li>
+</ul>
+
+<p>Several of these provoked interesting discussions on the mailing lists,
+worth searching for in the <a href="mail.html#archive">archives</a>.</p>
+
+<p>There are also several papers in languages other than English, see our <a
+href="web.html#otherlang">web links</a>.</p>
+
+<h3><a name="licensing">License and copyright information</a></h3>
+
+<p>All code and documentation written for this project is distributed under
+either the GNU General Public License (<a href="glossary.html#GPL">GPL</a>)
+or the GNU Library General Public License. For details see the COPYING file
+in the distribution.</p>
+
+<p>Not all code in the distribution is ours, however. See the CREDITS file
+for details. In particular, note that the <a
+href="glossary.html#LIBDES">Libdes</a> library and the version of <a
+href="glossary.html#MD5">MD5</a> that we use each have their own license.</p>
+
+<h2><a name="sites">Distribution sites</a></h2>
+
+<p>FreeS/WAN is available from a number of sites.</p>
+
+<h3>Primary site</h3>
+
+<p>Our primary site, is at xs4all (Thanks, folks!) in Holland:</p>
+<ul>
+  <li><a href="http://www.xs4all.nl/~freeswan">HTTP</a></li>
+  <li><a href="ftp://ftp.xs4all.nl/pub/crypto/freeswan">FTP</a></li>
+</ul>
+
+<h3><a name="mirrors">Mirrors</a></h3>
+
+<p>There are also mirror sites all over the world:</p>
+<ul>
+  <li><a href="http://www.flora.org/freeswan">Eastern Canada</a> (limited
+    resouces)</li>
+  <li><a href="ftp://ludwig.doculink.com/pub/freeswan/">Eastern Canada</a>
+    (has older versions too)</li>
+  <li><a href="ftp://ntsc.notBSD.org/pub/crypto/freeswan/">Eastern Canada</a>
+    (has older versions too)</li>
+  <li><a href="ftp://ftp.kame.net/pub/freeswan/">Japan</a></li>
+  <li><a href="ftp://ftp.futuredynamics.com/freecrypto/FreeSWAN/">Hong
+    Kong</a></li>
+  <li><a href="ftp://ipsec.dk/pub/freeswan/">Denmark</a></li>
+  <li><a href="ftp://ftp.net.lut.ac.uk/freeswan">the UK</a></li>
+  <li><a href="http://storm.alert.sk/comp/mirrors/freeswan/">Slovak
+    Republic</a></li>
+  <li><a
+    href="http://the.wiretapped.net/security/vpn-tunnelling/freeswan/">Australia</a></li>
+  <li><a href="http://freeswan.technolust.cx/">technolust</a></li>
+  <li><a href="http://freeswan.devguide.de/">Germany</a></li>
+  <li>Ivan Moore's <a href="http://snowcrash.tdyc.com/freeswan/">site</a></li>
+  <li>the <a href="http://www.cryptoarchive.net/">Crypto Archive</a> on the
+    <a href="http://www.securityportal.com/">Security Portal</a> site</li>
+  <li><a href="http://www.wiretapped.net/">Wiretapped.net</a> in
+  Australia</li>
+</ul>
+
+<p>Thanks to those folks as well.</p>
+
+<h3><a name="munitions">The "munitions" archive of Linux crypto
+software</a></h3>
+
+<p>There is also an archive of Linux crypto software called "munitions", with
+its own mirrors in a number of countries. It includes FreeS/WAN, though not
+always the latest version. Some of its sites are:</p>
+<ul>
+  <li><a href="http://munitions.vipul.net/">Germany</a></li>
+  <li><a href="http://munitions.iglu.cjb.net/">Italy</a></li>
+  <li><a href="http://munitions2.xs4all.nl/">Netherlands</a></li>
+</ul>
+
+<p>Any of those will have a list of other "munitions" mirrors. There is also
+a CD available.</p>
+
+<h2>Links to other sections</h2>
+
+<p>For more detailed background information, see:</p>
+<ul>
+  <li><a href="politics.html#politics">history and politics</a> of 
+   cryptography</li>
+  <li><a href="ipsec.html#ipsec.detail">IPsec protocols</a></li>
+</ul>
+
+<p>To begin working with FreeS/WAN, go to our <a
+href="quickstart.html#quick.guide">quickstart</a> guide.</p>
+</body>
+</html>
diff --git a/doc/src/ipsec.html b/doc/src/ipsec.html
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+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>IPsec protocols</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, FreeSWAN, protocol, ESP, AH, IKE">
+  <!--
+
+  Written by Sandy Harris for the Linux FreeS/WAN project
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: ipsec.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+
+<body>
+<h1><a name="ipsec.detail">The IPsec protocols</a></h1>
+
+<p>This section provides information on the IPsec protocols which FreeS/WAN
+implements. For more detail, see the <a href="rfc.html">RFCs</a>.</p>
+
+<p>The basic idea of IPsec is to provide security functions, <a
+href="glossary.html#authentication">authentication</a> and <a
+href="glossary.html#encryption">encryption</a>, at the IP (Internet Protocol)
+level. This requires a higher-level protocol (IKE) to set things up for the
+IP-level services (ESP and AH).</p>
+
+<h2>Protocols and phases</h2>
+
+<p>Three protocols are used in an IPsec implementation:</p>
+<dl>
+  <dt>ESP, Encapsulating Security Payload</dt>
+    <dd>Encrypts and/or authenticates data</dd>
+  <dt>AH, Authentication Header</dt>
+    <dd>Provides a packet authentication service</dd>
+  <dt>IKE, Internet Key Exchange</dt>
+    <dd>Negotiates connection parameters, including keys, for the other
+    two</dd>
+</dl>
+
+<p>The term "IPsec" (also written as IPSEC) is slightly ambiguous. In some
+contexts, it includes all three of the above but in other contexts it refers
+only to AH and ESP.</p>
+
+<p>There is more detail below, but a quick summary of how the whole thing
+works is:</p>
+<dl>
+  <dt>Phase one IKE (main mode exchange)</dt>
+    <dd>sets up a keying channel (ISAKMP SA) between the two gateways</dd>
+  <dt>Phase two IKE (quick mode exchange)</dt>
+    <dd>sets up data channels (IPsec SAs)</dd>
+  <dt>IPsec proper</dt>
+    <dd>exchanges data using AH or ESP</dd>
+</dl>
+
+<p>Both phases of IKE are repeated periodically to automate re-keying.</p>
+
+<h2><a name="others">Applying IPsec</a></h2>
+
+<p>Authentication and encryption functions for network data can, of course,
+be provided at other levels. Many security protocols work at levels above
+IP.</p>
+<ul>
+  <li><a href="glossary.html#PGP">PGP</a> encrypts and authenticates mail
+    messages</li>
+  <li><a href="glossary.html#SSH">SSH</a> authenticates remote logins and
+    then encrypts the session</li>
+  <li><a href="glossary.html#SSL">SSL</a> or <a
+    href="glossary.html#TLS">TLS</a> provides security at the sockets layer,
+    e.g. for secure web browsing</li>
+</ul>
+
+<p>and so on. Other techniques work at levels below IP. For example, data on
+a communications circuit or an entire network can be encrypted by specialised
+hardware. This is common practice in high-security applications.</p>
+
+<h3><a name="advantages">Advantages of IPsec</a></h3>
+
+<p>There are, however, advantages to doing it at the IP level instead of, or
+as well as, at other levels.</p>
+
+<p>IPsec is the <strong>most general way to provide these services for the
+Internet</strong>.</p>
+<ul>
+  <li>Higher-level services protect a <em>single protocol</em>; for example
+    PGP protects mail.</li>
+  <li>Lower level services protect a <em>single medium</em>; for example a
+    pair of encryption boxes on the ends of a line make wiretaps on that line
+    useless unless the attacker is capable of breaking the encryption.</li>
+</ul>
+
+<p>IPsec, however, can protect <em>any protocol</em> running above IP and
+<em>any medium</em> which IP runs over. More to the point, it can protect a
+mixture of application protocols running over a complex combination of media.
+This is the normal situation for Internet communication; IPsec is the only
+general solution.</p>
+
+<p>IPsec can also provide some security services "in the background", with
+<strong>no visible impact on users</strong>. To use <a
+href="glossary.html#PGP">PGP</a> encryption and signatures on mail, for
+example, the user must at least:</p>
+<ul>
+  <li>remember his or her passphrase,</li>
+  <li>keep it secure</li>
+  <li>follow procedures to validate correspondents' keys</li>
+</ul>
+
+<p>These systems can be designed so that the burden on users is not onerous,
+but any system will place some requirements on users. No such system can hope
+to be secure if users are sloppy about meeting those requirements. The author
+has seen username and password stuck on terminals with post-it notes in an
+allegedly secure environment, for example.</p>
+
+<h3><a name="limitations">Limitations of IPsec</a></h3>
+
+<p>IPsec is designed to secure IP links between machines. It does that well,
+but it is important to remember that there are many things it does not do.
+Some of the important limitations are:</p>
+<dl>
+  <dt><a name="depends">IPsec cannot be secure if your system isn't</a></dt>
+    <dd>System security on IPsec gateway machines is an essential requirement
+      if IPsec is to function as designed. No system can be trusted if the
+      underlying machine has been subverted. See books on Unix security such
+      as <a href="biblio.html#practical">Garfinkel and Spafford</a> or our
+      web references for <a href="web.html#linsec">Linux security</a> or more
+      general <a href="web.html#compsec">computer security</a>.
+      <p>Of course, there is another side to this. IPsec can be a powerful
+      tool for improving system and network security. For example, requiring
+      packet authentication makes various spoofing attacks harder and IPsec
+      tunnels can be extremely useful for secure remote administration of
+      various things.</p>
+    </dd>
+  <dt><a name="not-end-to-end">IPsec is not end-to-end</a></dt>
+    <dd>IPsec cannot provide the same end-to-end security as systems working
+      at higher levels. IPsec encrypts an IP connection between two machines,
+      which is quite a different thing than encrypting messages between users
+      or between applications.
+      <p>For example, if you need mail encrypted from the sender's desktop to
+      the recipient's desktop and decryptable only by the recipient, use <a
+      href="glossary.html#PGP">PGP</a> or another such system. IPsec can
+      encrypt any or all of the links involved -- between the two mail
+      servers, or between either server and its clients. It could even be
+      used to secure a direct IP link from the sender's desktop machine to
+      the recipient's, cutting out any sort of network snoop. What it cannot
+      ensure is end-to-end user-to-user security. If only IPsec is used to
+      secure mail, then anyone with appropriate privileges on any machine
+      where that mail is stored (at either end or on any store-and-forward
+      servers in the path) can read it.</p>
+      <p>In another common setup, IPsec encrypts packets at a security
+      gateway machine as they leave the sender's site and decrypts them on
+      arrival at the gateway to the recipient's site. This does provide a
+      useful security service -- only encrypted data is passed over the
+      Internet -- but it does not even come close to providing an end-to-end
+      service. In particular, anyone with appropriate privileges on either
+      site's LAN can intercept the message in unencrypted form.</p>
+    </dd>
+  <dt><a name="notpanacea">IPsec cannot do everything</a></dt>
+    <dd>IPsec also cannot provide all the functions of systems working at
+      higher levels of the protocol stack. If you need a document
+      electronically signed by a particular person, then you need his or her
+      <a href="glossary.html#signature">digital signature</a> and a <a
+      href="glossary.html#public">public key cryptosystem</a> to verify it
+      with.
+      <p>Note, however, that IPsec authentication of the underlying
+      communication can make various attacks on higher-level protocols more
+      difficult. In particular, authentication prevents <a
+      href="glossary.html#middle">man-in-the-middle attacks</a>.</p>
+    </dd>
+  <dt><a name="no_user">IPsec authenticates machines, not users</a></dt>
+    <dd>IPsec uses strong authentication mechanisms to control which messages
+      go to which machines, but it does not have the concept of user ID,
+      which is vital to many other security mechansims and policies. This
+      means some care must be taken in fitting the various security
+      mechansims on a network together. For example, if you need to control
+      which users access your database server, you need some non-IPsec
+      mechansim for that. IPsec can control which machines connect to the
+      server, and can ensure that data transfer to those machines is done
+      securely, but that is all. Either the machines themselves must control
+      user access or there must be some form of user authentication to the
+      database, independent of IPsec.</dd>
+  <dt><a name="DoS">IPsec does not stop denial of service attacks</a></dt>
+    <dd><a href="glossary.html#DOS">Denial of service</a> attacks aim at
+      causing a system to crash, overload, or become confused so that
+      legitimate users cannot get whatever services the system is supposed to
+      provide. These are quite different from attacks in which the attacker
+      seeks either to use the service himself or to subvert the service into
+      delivering incorrect results.
+      <p>IPsec shifts the ground for DoS attacks; the attacks possible
+      against systems using IPsec are different than those that might be used
+      against other systems. It does not, however, eliminate the possibility
+      of such attacks.</p>
+    </dd>
+  <dt><a name="traffic">IPsec does not stop traffic analysis</a></dt>
+    <dd><a href="glossary.html#traffic">Traffic analysis</a> is the attempt
+      to derive intelligence from messages without regard for their contents.
+      In the case of IPsec, it would mean analysis based on things visible in
+      the unencrypted headers of encrypted packets -- source and destination
+      gateway addresses, packet size, et cetera. Given the resources to
+      acquire such data and some skill in analysing it (both of which any
+      national intelligence agency should have), this can be a very powerful
+      technique.
+      <p>IPsec is not designed to defend against this. Partial defenses are
+      certainly possible, and some are <a href="#traffic.resist">described
+      below</a>, but it is not clear that any complete defense can be
+      provided.</p>
+    </dd>
+</dl>
+
+<h3><a name="uses">IPsec is a general mechanism for securing IP</a></h3>
+
+<p>While IPsec does not provide all functions of a mail encryption package,
+it can encrypt your mail. In particular, it can ensure that all mail passing
+between a pair or a group of sites is encrypted. An attacker looking only at
+external traffic, without access to anything on or behind the IPsec gateway,
+cannot read your mail. He or she is stymied by IPsec just as he or she would
+be by <a href="glossary.html#PGP">PGP</a>.</p>
+
+<p>The advantage is that IPsec can provide the same protection for <strong>
+anything transmitted over IP</strong>. In a corporate network example, PGP
+lets the branch offices exchange secure mail with head office. SSL and SSH
+allow them to securely view web pages, connect as terminals to machines, and
+so on. IPsec can support all those applications, plus database queries, file
+sharing (NFS or Windows), other protocols encapsulated in IP (Netware,
+Appletalk, ...), phone-over-IP, video-over-IP, ... anything-over-IP. The only
+limitation is that IP Multicast is not yet supported, though there are
+Internet Draft documents for that.</p>
+
+<p>IPsec creates <strong>secure tunnels through untrusted networks</strong>.
+Sites connected by these tunnels form VPNs, <a
+href="glossary.html#VPN">Virtual Private Networks</a>.</p>
+
+<p>IPsec gateways can be installed wherever they are required.</p>
+<ul>
+  <li>One organisation might choose to install IPsec only on firewalls
+    between their LANs and the Internet. This would allow them to create a
+    VPN linking several offices. It would provide protection against anyone
+    outside their sites.</li>
+  <li>Another might install IPsec on departmental servers so everything on
+    the corporate backbone net was encrypted. This would protect messages on
+    that net from everyone except the sending and receiving department.</li>
+  <li>Another might be less concerned with information secrecy and more with
+    controlling access to certain resources. They might use IPsec packet
+    authentication as part of an access control mechanism, with or without
+    also using the IPsec encryption service.</li>
+  <li>It is even possible (assuming adequate processing power and an IPsec
+    implementation in each node) to make every machine its own IPsec gateway
+    so that everything on a LAN is encrypted. This protects information from
+    everyone outside the sending and receiving machine.</li>
+  <li>These techniques can be combined in various ways. One might, for
+    example, require authentication everywhere on a network while using
+    encryption only for a few links.</li>
+</ul>
+
+<p>Which of these, or of the many other possible variants, to use is up to
+you. <strong>IPsec provides mechanisms; you provide the policy</strong>.</p>
+
+<p><strong>No end user action is required</strong> for IPsec security to be
+used; they don't even have to know about it. The site administrators, of
+course, do have to know about it and to put some effort into making it work.
+Poor administration can compromise IPsec as badly as the post-it notes
+mentioned above. It seems reasonable, though, for organisations to hope their
+system administrators are generally both more security-conscious than end
+users and more able to follow computer security procedures. If not, at least
+there are fewer of them to educate or replace.</p>
+
+<p>IPsec can be, and often should be, used with along with security protocols
+at other levels. If two sites communicate with each other via the Internet,
+then IPsec is the obvious way to protect that communication. If two others
+have a direct link between them, either link encryption or IPsec would make
+sense. Choose one or use both. Whatever you use at and below the IP level,
+use other things as required above that level. Whatever you use above the IP
+level, consider what can be done with IPsec to make attacks on the higher
+levels harder. For example, <a href="glossary.html#middle">man-in-the-middle
+attacks</a> on various protocols become difficult if authentication at packet
+level is in use on the potential victims' communication channel.</p>
+
+<h3><a name="authonly">Using authentication without encryption</a></h3>
+
+<p>Where appropriate, IPsec can provide authentication without encryption.
+One might do this, for example:</p>
+<ul>
+  <li>where the data is public but one wants to be sure of getting the right
+    data, for example on some web sites</li>
+  <li>where encryption is judged unnecessary, for example on some company or
+    department LANs</li>
+  <li>where strong encryption is provided at link level, below IP</li>
+  <li>where strong encryption is provided in other protocols, above IP<br>
+    Note that IPsec authentication may make some attacks on those protocols
+    harder.</li>
+</ul>
+
+<p>Authentication has lower overheads than encryption.</p>
+
+<p>The protocols provide four ways to build such connections, using either an
+AH-only connection or ESP using null encryption, and in either manually or
+automatically keyed mode. FreeS/WAN supports only one of these, manually
+keyed AH-only connections, and <strong>we do not recommend using
+that</strong>. Our reasons are discussed under <a
+href="#traffic.resist">Resisting traffic analysis</a> a few sections further
+along.</p>
+
+<h3><a name="encnoauth">Encryption without authentication is
+dangerous</a></h3>
+
+<p>Originally, the IPsec encryption protocol <a
+href="glossary.html#ESP">ESP</a> didn't do integrity checking. It only did
+encryption. Steve Bellovin found many ways to attack ESP used without
+authentication. See his paper <a
+href="http://www.research.att.com/~smb/papers/badesp.ps">Problem areas for
+the IP Security Protocols</a>. To make a secure connection, you had to add an
+<a href="glossary.html#AH">AH</a> Authentication Header as well as ESP.
+Rather than incur the overhead of several layers (and rather than provide an
+ESP layer that didn't actually protect the traffic), the IPsec working group
+built integrity and replay checking directly into ESP.</p>
+
+<p>Today, typical usage is one of:</p>
+<ul>
+  <li>ESP for encryption and authentication</li>
+  <li>AH for authentication alone</li>
+</ul>
+
+<p>Other variants are allowed by the standard, but not much used:</p>
+<dl>
+  <dt>ESP encryption without authentication</dt>
+    <dd><strong>Bellovin has demonstrated fatal flaws in this. Do not
+      use.</strong></dd>
+  <dt>ESP encryption with AH authentication</dt>
+    <dd>This has higher overheads than using the authentication in ESP, and
+      no obvious benefit in most cases. The exception might be a network
+      where AH authentication was widely or universally used. If you're going
+      to do AH to conform with network policy, why authenticate again in the
+      ESP layer?</dd>
+  <dt>Authenticate twice, with AH and with ESP</dt>
+    <dd>Why? Of course, some folk consider "belt and suspenders" the sensible
+      approach to security. If you're among them, you might use both
+      protocols here. You might also use both to satisfy different parts of a
+      security policy. For example, an organisation might require AH
+      authentication everywhere but two users within the organisation might
+      use ESP as well.</dd>
+  <dt>ESP authentication without encryption</dt>
+    <dd>The standard allows this, calling it "null encryption". FreeS/WAN
+      does not support it. We recommend that you use AH instead if
+      authentication is all you require. AH authenticates parts of the IP
+      header, which ESP-null does not do.</dd>
+</dl>
+
+<p>Some of these variants cannot be used with FreeS/WAN because we do not
+support ESP-null and do not support automatic keying of AH-only
+connections.</p>
+
+<p>There are fairly frequent suggestions that AH be dropped entirely from the
+IPsec specifications since ESP and null encryption can handle that situation.
+It is not clear whether this will occur. My guess is that it is unlikely.</p>
+
+<h3><a name="multilayer">Multiple layers of IPsec processing are
+possible</a></h3>
+
+<p>The above describes combinations possible on a single IPsec connection. In
+a complex network you may have several layers of IPsec in play, with any of
+the above combinations at each layer.</p>
+
+<p>For example, a connection from a desktop machine to a database server
+might require AH authentication. Working with other host, network and
+database security measures, AH might be just the thing for access control.
+You might decide not to use ESP encryption on such packets, since it uses
+resources and might complicate network debugging. Within the site where the
+server is, then, only AH would be used on those packets.</p>
+
+<p>Users at another office, however, might have their whole connection (AH
+headers and all) passing over an IPsec tunnel connecting their office to the
+one with the database server. Such a tunnel should use ESP encryption and
+authentication. You need authentication in this layer because without
+authentication the encryption is vulnerable and the gateway cannot verify the
+AH authentication. The AH is between client and database server; the gateways
+aren't party to it.</p>
+
+<p>In this situation, some packets would get multiple layers of IPsec applied
+to them, AH on an end-to-end client-to-server basis and ESP from one office's
+security gateway to the other.</p>
+
+<h3><a name="traffic.resist">Resisting traffic analysis</a></h3>
+
+<p><a href="glossary.html#traffic">Traffic analysis</a> is the attempt to
+derive useful intelligence from encrypted traffic without breaking the
+encryption.</p>
+
+<p>Is your CEO exchanging email with a venture capital firm? With bankruptcy
+trustees? With an executive recruiting agency? With the holder of some
+important patents? If an eavesdropper learns about any of those, then he has
+interesting intelligence on your company, whether or not he can read the
+messages themselves.</p>
+
+<p>Even just knowing that there is network traffic between two sites may tell
+an analyst something useful, especially when combined with whatever other
+information he or she may have. For example, if you know Company A is having
+cashflow problems and Company B is looking for aquisitions, then knowing that
+packets are passing between the two is interesting. It is more interesting if
+you can tell it is email, and perhaps yet more if you know the sender and
+recipient.</p>
+
+<p>Except in the simplest cases, traffic analysis is hard to do well. It
+requires both considerable resources and considerable analytic skill.
+However, intelligence agencies of various nations have been doing it for
+centuries and many of them are likely quite good at it by now. Various
+commercial organisations, especially those working on "targeted marketing"
+may also be quite good at analysing certain types of traffic.</p>
+
+<p>In general, defending against traffic analysis is also difficult.
+Inventing a really good defense could get you a PhD and some interesting job
+offers.</p>
+
+<p>IPsec is not designed to stop traffic analysis and we know of no plausible
+method of extending it to do so. That said, there are ways to make traffic
+analysis harder. This section describes them.</p>
+
+<h4><a name="extra">Using "unnecessary" encryption</a></h4>
+
+<p>One might choose to use encryption even where it appears unnecessary in
+order to make analysis more difficult. Consider two offices which pass a
+small volume of business data between them using IPsec and also transfer
+large volumes of Usenet news. At first glance, it would seem silly to encrypt
+the newsfeed, except possibly for any newsgroups that are internal to the
+company. Why encrypt data that is all publicly available from many sites?</p>
+
+<p>However, if we encrypt a lot of news and send it down the same connection
+as our business data, we make <a href="glossary.html#traffic">traffic
+analysis</a> much harder. A snoop cannot now make inferences based on
+patterns in the volume, direction, sizes, sender, destination, or timing of
+our business messages. Those messages are hidden in a mass of news messages
+encapsulated in the same way.</p>
+
+<p>If we're going to do this we need to ensure that keys change often enough
+to remain secure even with high volumes and with the adversary able to get
+plaintext of much of the data. We also need to look at other attacks this
+might open up. For example, can the adversary use a chosen plaintext attack,
+deliberately posting news articles which, when we receive and encrypt them,
+will help break our encryption? Or can he block our business data
+transmission by flooding us with silly news articles? Or ...</p>
+
+<p>Also, note that this does not provide complete protection against traffic
+analysis. A clever adversary might still deduce useful intelligence from
+statistical analysis (perhaps comparing the input newsfeed to encrypted
+output, or comparing the streams we send to different branch offices), or by
+looking for small packets which might indicate establishment of TCP
+connections, or ...</p>
+
+<p>As a general rule, though, to improve resistance to traffic analysis, you
+should <strong>encrypt as much traffic as possible, not just as much as seems
+necessary.</strong></p>
+
+<h4><a name="multi-encrypt">Using multiple encryption</a></h4>
+
+<p>This also applies to using multiple layers of encryption. If you have an
+IPsec tunnel between two branch offices, it might appear silly to send <a
+href="glossary.html#PGP">PGP</a>-encrypted email through that tunnel.
+However, if you suspect someone is snooping your traffic, then it does make
+sense:</p>
+<ul>
+  <li>it protects the mail headers; they cannot even see who is mailing
+  who</li>
+  <li>it protects against user bungles or software malfunctions that
+    accidentally send messages in the clear</li>
+  <li>it makes any attack on the mail encryption much harder; they have to
+    break IPsec or break into your network before they can start on the mail
+    encryption</li>
+</ul>
+
+<p>Similar arguments apply for <a href="glossary.html#SSL">SSL</a>-encrypted
+web traffic or <a href="glossary.html#SSH">SSH</a>-encrypted remote login
+sessions, even for end-to-end IPsec tunnels between systems in the two
+offices.</p>
+
+<h4><a name="fewer">Using fewer tunnels</a></h4>
+
+<p>It may also help to use fewer tunnels. For example, if all you actually
+need encrypted is connections between:</p>
+<ul>
+  <li>mail servers at branch and head offices</li>
+  <li>a few branch office users and the head office database server</li>
+</ul>
+
+<p>You might build one tunnel per mail server and one per remote database
+user, restricting traffic to those applications. This gives the traffic
+analyst some information, however. He or she can distinguish the tunnels by
+looking at information in the ESP header and, given that distinction and the
+patterns of tunnel usage, might be able to figure out something useful.
+Perhaps not, but why take the risk?</p>
+
+<p>We suggest instead that you build one tunnel per branch office, encrypting
+everything passing from head office to branches. This has a number of
+advantages:</p>
+<ul>
+  <li>it is easier to build and administer</li>
+  <li>it resists traffic analysis somewhat better</li>
+  <li>it provides security for whatever you forgot. For example, if some user
+    at a remote office browses proprietary company data on some head office
+    web page (that the security people may not even know about!), then that
+    data is encrypted before it reaches the Internet.</li>
+</ul>
+
+<p>Of course you might also want to add additional tunnels. For example, if
+some of the database data is confidential and should not be exposed even
+within the company, then you need protection from the user's desktop to the
+database server. We suggest you do that in whatever way seems appropriate --
+IPsec, SSH or SSL might fit -- but, whatever you choose, pass it between
+locations via a gateway-to-gateway IPsec tunnel to provide some resistance to
+traffic analysis.</p>
+
+<h2><a name="primitives">Cryptographic components</a></h2>
+
+<p>IPsec combines a number of cryptographic techniques, all of them
+well-known and well-analyzed. The overall design approach was conservative;
+no new or poorly-understood components were included.</p>
+
+<p>This section gives a brief overview of each technique. It is intended only
+as an introduction. There is more information, and links to related topics,
+in our <a href="glossary.html">glossary</a>. See also our <a
+href="biblio.html">bibliography</a> and cryptography <a
+href="web.html#crypto.link">web links</a>.</p>
+
+<h3><a name="block.cipher">Block ciphers</a></h3>
+
+<p>The <a href="glossary.html#encryption">encryption</a> in the <a
+href="glossary.html#ESP">ESP</a> encapsulation protocol is done with a <a
+href="glossary.html#block">block cipher</a>.</p>
+
+<p>We do not implement <a href="glossary.html#DES">single DES</a>. It is <a
+href="politics.html#desnotsecure">insecure</a>. Our default, and currently
+only, block cipher is <a href="glossary.html#3DES">triple DES</a>.</p>
+
+<p>The <a href="glossary.html#rijndael">Rijndael</a> block cipher has won the
+<a href="glossary.html#AES">AES</a> competition to choose a relacement for
+DES. It will almost certainly be added to FreeS/WAN and to other IPsec
+implementations. <a href="web.html#patch">Patches</a> are already
+available.</p>
+
+<h3><a name="hash.ipsec">Hash functions</a></h3>
+
+<h4><a name="hmac.ipsec">The HMAC construct</a></h4>
+
+<p>IPsec packet authentication is done with the <a
+href="glossary.html#HMAC">HMAC</a> construct. This is not just a hash of the
+packet data, but a more complex operation which uses both a hashing algorithm
+and a key. It therefore does more than a simple hash would. A simple hash
+would only tell you that the packet data was not changed in transit, or that
+whoever changed it also regenerated the hash. An HMAC also tells you that the
+sender knew the HMAC key.</p>
+
+<p>For IPsec HMAC, the output of the hash algorithm is truncated to 96 bits.
+This saves some space in the packets. More important, it prevents an attacker
+from seeing all the hash output bits and perhaps creating some sort of attack
+based on that knowledge.</p>
+
+<h4>Choice of hash algorithm</h4>
+
+<p>The IPsec RFCs require two hash algorithms -- <a
+href="glossary.html#MD5">MD5</a> and <a href="glossary.html#SHA">SHA-1</a> --
+both of which FreeS/WAN implements.</p>
+
+<p>Various other algorithms -- such as RIPEMD and Tiger -- are listed in the
+RFCs as optional. None of these are in the FreeS/WAN distribution, or are
+likely to be added, although user <a href="web.html#patch">patches</a> exist
+for several of them.</p>
+
+<p>Additional hash algorithms -- <a href="glossary.html#SHA-256">SHA-256,
+SHA-384 and SHA-512</a> -- may be required to give hash strength matching the
+strength of <a href="glossary.html#AES">AES</a>. These are likely to be added
+to FreeS/WAN along with AES.</p>
+
+<h3><a name="DH.keying">Diffie-Hellman key agreement</a></h3>
+
+<p>The <a href="glossary.html#DH">Diffie-Hellman</a> key agreement protocol
+allows two parties (A and B or <a href="glossary.html#alicebob">Alice and
+Bob</a>) to agree on a key in such a way that an eavesdropper who intercepts
+the entire conversation cannot learn the key.</p>
+
+<p>The protocol is based on the <a href="glossary.html#dlog">discrete
+logarithm</a> problem and is therefore thought to be secure. Mathematicians
+have been working on that problem for years and seem no closer to a solution,
+though there is no proof that an efficient solution is impossible.</p>
+
+<h3><a name="RSA.auth">RSA authentication</a></h3>
+
+<p>The <a href="glossary.html#RSA">RSA</a> algorithm (named for its inventors
+-- Rivest, Shamir and Adleman) is a very widely used <a
+href="glossary.html#">public key</a> cryptographic technique. It is used in
+IPsec as one method of authenticating gateways for Diffie-Hellman key
+negotiation.</p>
+
+<h2><a name="structure">Structure of IPsec</a></h2>
+
+<p>There are three protocols used in an IPsec implementation:</p>
+<dl>
+  <dt>ESP, Encapsulating Security Payload</dt>
+    <dd>Encrypts and/or authenticates data</dd>
+  <dt>AH, Authentication Header</dt>
+    <dd>Provides a packet authentication service</dd>
+  <dt>IKE, Internet Key Exchange</dt>
+    <dd>Negotiates connection parameters, including keys, for the other
+    two</dd>
+</dl>
+
+<p>The term "IPsec" is slightly ambiguous. In some contexts, it includes all
+three of the above but in other contexts it refers only to AH and ESP.</p>
+
+<h3><a name="IKE.ipsec">IKE (Internet Key Exchange)</a></h3>
+
+<p>The IKE protocol sets up IPsec (ESP or AH) connections after negotiating
+appropriate parameters (algorithms to be used, keys, connection lifetimes)
+for them. This is done by exchanging packets on UDP port 500 between the two
+gateways.</p>
+
+<p>IKE (RFC 2409) was the outcome of a long, complex process in which quite a
+number of protocols were proposed and debated. Oversimplifying mildly, IKE
+combines:</p>
+<dl>
+  <dt>ISAKMP (RFC 2408)</dt>
+    <dd>The <strong>I</strong>nternet <strong>S</strong>ecurity
+      <strong>A</strong>ssociation and <strong>K</strong>ey
+      <strong>M</strong>anagement <strong>P</strong>rotocol manages
+      negotiation of connections and defines <a
+      href="glossary.html#SA">SA</a>s (Security Associations) as a means of
+      describing connection properties.</dd>
+  <dt>IPsec DOI for ISAKMP (RFC 2407)</dt>
+    <dd>A <strong>D</strong>omain <strong>O</strong>f
+      <strong>I</strong>nterpretation fills in the details necessary to turn
+      the rather abstract ISAKMP protocol into a more tightly specified
+      protocol, so it becomes applicable in a particular domain.</dd>
+  <dt>Oakley key determination protocol (RFC 2412)</dt>
+    <dd>Oakley creates keys using the <a
+      href="glossary.html#DH">Diffie-Hellman</a> key agreement protocol.</dd>
+</dl>
+
+<p>For all the details, you would need to read the four <a
+href="rfc.html">RFCs</a> just mentioned (over 200 pages) and a number of
+others. We give a summary below, but it is far from complete.</p>
+
+<h4><a name="phases">Phases of IKE</a></h4>
+
+<p>IKE negotiations have two phases.</p>
+<dl>
+  <dt>Phase one</dt>
+    <dd>The two gateways negotiate and set up a two-way ISAKMP SA which they
+      can then use to handle phase two negotiations. One such SA between a
+      pair of gateways can handle negotiations for multiple tunnels.</dd>
+  <dt>Phase two</dt>
+    <dd>Using the ISAKMP SA, the gateways negotiate IPsec (ESP and/or AH) SAs
+      as required. IPsec SAs are unidirectional (a different key is used in
+      each direction) and are always negotiated in pairs to handle two-way
+      traffic. There may be more than one pair defined between two
+    gateways.</dd>
+</dl>
+
+<p>Both of these phases use the UDP protocol and port 500 for their
+negotiations.</p>
+
+<p>After both IKE phases are complete, you have IPsec SAs to carry your
+encrypted data. These use the ESP or AH protocols. These protocols do not
+have ports. Ports apply only to UDP or TCP.</p>
+
+<p>The IKE protocol is designed to be extremely flexible. Among the things
+that can be negotiated (separately for each SA) are:</p>
+<ul>
+  <li>SA lifetime before rekeying</li>
+  <li>encryption algorithm used. We currently support only <a
+    href="glossary.html#3DES">triple DES</a>. Single DES is <a
+    href="politics.html#desnotsecure">insecure</a>. The RFCs say you MUST do
+    DES, SHOULD do 3DES and MAY do various others. We do not do any of the
+    others.</li>
+  <li>authentication algorithms. We support <a
+    href="glossary.html#MD5">MD5</a> and <a href="glossary.html#SHA">SHA</a>.
+    These are the two the RFCs require.</li>
+  <li>choice of group for <a href="glossary.html#DH">Diffie-Hellman</a> key
+    agreement. We currently support Groups 2 and 5 (which are defined modulo
+    primes of various lengths) and do not support Group 1 (defined modulo a
+    shorter prime, and therefore cryptographically weak) or groups 3 and 4
+    (defined using elliptic curves). The RFCs require only Group 1.</li>
+</ul>
+
+<p>The protocol also allows implementations to add their own encryption
+algorithms, authentication algorithms or Diffie-Hellman groups. We do not
+support any such extensions, but there are some <a
+href="web.html#patch">patches</a> that do.</p>
+
+<p>There are a number of complications:</p>
+<ul>
+  <li>The gateways must be able to authenticate each other's identities
+    before they can create a secure connection. This host authentication is
+    part of phase one negotiations, and is a required prerequisite for packet
+    authentication used later. Host authentication can be done in a variety
+    of ways. Those supported by FreeS/WAN are discussed in our <a
+    href="adv_config.html#auto-auth">advanced configuration</a> document.</li>
+  <li>Phase one can be done in two ways.
+    <ul>
+      <li>Main Mode is required by the RFCs and supported in FreeS/WAN. It
+        uses a 6-packet exzchange.</li>
+      <li>Aggressive Mode is somewhat faster (only 3 packets) but reveals
+        more to an eavesdropper. This is optional in the RFCs, not currently
+        supported by FreeS/WAN, and not likely to be.</li>
+    </ul>
+  </li>
+  <li>A new group exchange may take place after phase one but before phase
+    two, defining an additional group for use in the <a
+    href="glossary.html#DH">Diffie-Hellman</a> key agreement part of phase
+    two. FreeS/WAN does not currently support this.</li>
+  <li>Phase two always uses Quick Mode, but there are two variants of that:
+    <ul>
+      <li>One variant provides <a href="glossary.html#PFS">Perfect Forward
+        Secrecy (PFS)</a>. An attacker that obtains your long-term host
+        authentication key does not immediately get any of your short-term
+        packet encryption of packet authentication keys. He must conduct
+        another successful attack each time you rekey to get the short-term
+        keys. Having some short-term keys does not help him learn others. In
+        particular, breaking your system today does not let him read messages
+        he archived yestarday, assuming you've changed short-term keys in the
+        meanwhile. We enable PFS as the default.</li>
+      <li>The other variant disables PFS and is therefore slightly faster. We
+        do not recommend this since it is less secure, but FreeS/WAN does
+        support it. You can enable it with a <var>pfs=no</var> statement in
+        <a href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a>.</li>
+      <li>The protocol provides no way to negotiate which variant will be
+        used. If one gateway is set for PFS and the other is not, the
+        negotiation fails. This has proved a fairly common source of
+        interoperation problems.</li>
+    </ul>
+  </li>
+  <li>Several types of notification message may be sent by either side during
+    either phase, or later. FreeS/WAN does not currently support these, but
+    they are a likely addition in future releases.</li>
+  <li>There is a commit flag which may optionally be set on some messages.
+    The <a href="http://www.lounge.org/ike_doi_errata.html">errata</a> page
+    for the RFCs includes two changes related to this, one to clarify the
+    description of its use and one to block a <a
+    href="glossary.html#DOS">denial of service</a> attack which uses it. We
+    currently do not implement this feature.</li>
+</ul>
+
+<p>These complications can of course lead to problems, particularly when two
+different implementations attempt to interoperate. For example, we have seen
+problems such as:</p>
+<ul>
+  <li>Some implementations (often products crippled by <a
+    href="politics.html#exlaw">export laws</a>) have the insecure DES
+    algorithm as their only supported encryption method. Other parts of our
+    documentation discuss the <a
+    href="politics.html#desnotsecure">reasons we do not implement single
+    DES</a>, and <a href="interop.html#noDES">how to cope with crippled
+    products</a>.</li>
+  <li>Windows 2000 IPsec tries to negotiate using Aggressive Mode, which we
+    don't support. Later on, it uses the commit bit, which we also don't
+    support.</li>
+  <li>Various implementations disable PFS by default, and therefore will not
+    talk to FreeS/WAN until you either turn on PFS on their end or turn it
+    off in FreeS/WAN with a <var>pfs=no</var> entry in the connection
+    description.</li>
+  <li>FreeS/WAN's interaction with PGPnet is complicated by their use of
+    notification messages we do not yet support.</li>
+</ul>
+
+<p>Despite this, we do interoperate successfully with many implementations,
+including both Windows 2000 and PGPnet. Details are in our <a
+href="interop.html">interoperability</a> document.</p>
+
+<h4><a name="sequence">Sequence of messages in IKE</a></h4>
+
+<p>Each phase (see <a href="#phases">previous section</a>)of IKE involves a
+series of messages. In Pluto error messages, these are abbreviated using:</p>
+<dl>
+  <dt>M</dt>
+    <dd><strong>M</strong>ain mode, settting up the keying channel (ISAKMP
+    SA)</dd>
+  <dt>Q</dt>
+    <dd><strong>Q</strong>uick mode, setting up the data channel (IPsec
+    SA)</dd>
+  <dt>I</dt>
+    <dd><strong>I</strong>nitiator, the machine that starts the
+    negotiation</dd>
+  <dt>R</dt>
+    <dd><strong>R</strong>esponder</dd>
+</dl>
+
+<p>For example, the six messages of a main mode negotiation, in sequence, are
+labelled:</p>
+<pre>       MI1 ----------&gt;
+           &lt;---------- MR1
+       MI2 ----------&gt; 
+           &lt;---------- MR2
+       MI3 ----------&gt;
+           &lt;---------- MR3</pre>
+
+<h4><a name="struct.exchange">Structure of IKE messages</a></h4>
+
+<p>Here is our Pluto developer explaining some of this on the mailing
+list:</p>
+<pre>When one IKE system (for example, Pluto) is negotiating with another
+to create an SA, the Initiator proposes a bunch of choices and the
+Responder replies with one that it has selected.
+
+The structure of the choices is fairly complicated.  An SA payload
+contains a list of lists of "Proposals".  The outer list is a set of
+choices: the selection must be from one element of this list.
+
+Each of these elements is a list of Proposals.  A selection must be
+made from each of the elements of the inner list.  In other words,
+*all* of them apply (that is how, for example, both AH and ESP can
+apply at once).
+
+Within each of these Proposals is a list of Transforms.  For each
+Proposal selected, one Transform must be selected (in other words,
+each Proposal provides a choice of Transforms).
+
+Each Transform is made up of a list of Attributes describing, well,
+attributes.  Such as lifetime of the SA.  Such as algorithm to be
+used.  All the Attributes apply to a Transform.
+
+You will have noticed a pattern here: layers alternate between being
+disjunctions ("or") and conjunctions ("and").
+
+For Phase 1 / Main Mode (negotiating an ISAKMP SA), this structure is
+cut back.  There must be exactly one Proposal.  So this degenerates to
+a list of Transforms, one of which must be chosen.</pre>
+
+<h3><a name="services">IPsec Services, AH and ESP</a></h3>
+
+<p>IPsec offers two services, <a
+href="glossary.html#authentication">authentication</a> and <a
+href="glossary.html#encryption">encryption</a>. These can be used separately
+but are often used together.</p>
+<dl>
+  <dt>Authentication</dt>
+    <dd>Packet-level authentication allows you to be confident that a packet
+      came from a particular machine and that its contents were not altered
+      en route to you. No attempt is made to conceal or protect the contents,
+      only to assure their integrity. Packet authentication can be provided
+      separately using an <a href="glossary.html#AH">Authentication
+      Header</a>, described just below, or it can be included as part of the
+      <a href="glossary.html#ESP">ESP</a> (Encapsulated Security Payload)
+      service, described in the following section. That service offers
+      encryption as well as authentication. In either case, the <a
+      href="glossary.html#HMAC">HMAC</a> construct is used as the
+      authentication mechanism.
+      <p>There is a separate authentication operation at the IKE level, in
+      which each gateway authenticates the other. This can be done in a
+      variety of ways.</p>
+    </dd>
+  <dt>Encryption</dt>
+    <dd>Encryption allows you to conceal the contents of a message from
+      eavesdroppers.
+      <p>In IPsec this is done using a <a href="glossary.html#block">block
+      cipher</a> (normally <a href="glossary.html#3DES">Triple DES</a> for
+      Linux). In the most used setup, keys are automatically negotiated, and
+      periodically re-negotiated, using the <a
+      href="glossary.html#IKE">IKE</a> (Internet Key Exchange) protocol. In
+      Linux FreeS/WAN this is handled by the Pluto Daemon.</p>
+      <p>The IPsec protocol offering encryption is <a
+      href="glossary.html#ESP">ESP</a>, Encapsulated Security Payload. It can
+      also include a packet authentication service.</p>
+    </dd>
+</dl>
+
+<p>Note that <strong>encryption should always be used with some packet
+authentication service</strong>. Unauthenticated encryption is vulnerable to
+<a href="glossary.html#middle">man-in-the-middle attacks</a>. Also note that
+encryption does not prevent <a href="glossary.html#traffic">traffic
+analysis</a>.</p>
+
+<h3><a name="AH.ipsec">The Authentication Header (AH)</a></h3>
+
+<p>Packet authentication can be provided separately from encryption by adding
+an authentication header (AH) after the IP header but before the other
+headers on the packet. This is the subject of this section. Details are in
+RFC 2402.</p>
+
+<p>Each of the several headers on a packet header contains a "next protocol"
+field telling the system what header to look for next. IP headers generally
+have either TCP or UDP in this field. When IPsec authentication is used, the
+packet IP header has AH in this field, saying that an Authentication Header
+comes next. The AH header then has the next header type -- usually TCP, UDP
+or encapsulated IP.</p>
+
+<p>IPsec packet authentication can be added in transport mode, as a
+modification of standard IP transport. This is shown in this diagram from the
+RFC:</p>
+<pre>                  BEFORE APPLYING AH
+            ----------------------------
+      IPv4  |orig IP hdr  |     |      |
+            |(any options)| TCP | Data |
+            ----------------------------
+
+                  AFTER APPLYING AH
+            ---------------------------------
+      IPv4  |orig IP hdr  |    |     |      |
+            |(any options)| AH | TCP | Data |
+            ---------------------------------
+            ||
+                 except for mutable fields</pre>
+
+<p>Athentication can also be used in tunnel mode, encapsulating the
+underlying IP packet beneath AH and an additional IP header.</p>
+<pre>                         ||
+IPv4  | new IP hdr* |    | orig IP hdr*  |    |      |
+      |(any options)| AH | (any options) |TCP | Data |
+      ------------------------------------------------
+      ||
+      |           in the new IP hdr                  |</pre>
+
+<p>This would normally be used in a gateway-to-gateway tunnel. The receiving
+gateway then strips the outer IP header and the AH header and forwards the
+inner IP packet.</p>
+
+<p>The mutable fields referred to are things like the time-to-live field in
+the IP header. These cannot be included in authentication calculations
+because they change as the packet travels.</p>
+
+<h4><a name="keyed">Keyed MD5 and Keyed SHA</a></h4>
+
+<p>The actual authentication data in the header is typically 96 bits and
+depends both on a secret shared between sender and receiver and on every byte
+of the data being authenticated. The technique used is <a
+href="glossary.html#HMAC">HMAC</a>, defined in RFC 2104.</p>
+
+<p>The algorithms involved are the <a href="glossary.html#MD5">MD5</a>
+Message Digest Algorithm or <a href="glossary.html#SHA">SHA</a>, the Secure
+Hash Algorithm. For details on their use in this application, see RFCs 2403
+and 2404 respectively.</p>
+
+<p>For descriptions of the algorithms themselves, see RFC 1321 for MD5 and <a
+href="glossary.html#FIPS">FIPS</a> (Federal Information Processing Standard)
+number 186 from <a href="glossary.html#NIST">NIST</a>, the US National
+Institute of Standards and Technology for SHA. <a
+href="biblio.html#schneier"><cite>Applied Cryptography</cite></a> covers both
+in some detail, MD5 starting on page 436 and SHA on 442.</p>
+
+<p>These algorithms are intended to make it nearly impossible for anyone to
+alter the authenticated data in transit. The sender calculates a digest or
+hash value from that data and includes the result in the authentication
+header. The recipient does the same calculation and compares results. For
+unchanged data, the results will be identical. The hash algorithms are
+designed to make it extremely difficult to change the data in any way and
+still get the correct hash.</p>
+
+<p>Since the shared secret key is also used in both calculations, an
+interceptor cannot simply alter the authenticated data and change the hash
+value to match. Without the key, he or she (or even the dreaded They) cannot
+produce a usable hash.</p>
+
+<h4><a name="sequence">Sequence numbers</a></h4>
+
+<p>The authentication header includes a sequence number field which the
+sender is required to increment for each packet. The receiver can ignore it
+or use it to check that packets are indeed arriving in the expected
+sequence.</p>
+
+<p>This provides partial protection against <a
+href="glossary.html#replay">replay attacks</a> in which an attacker resends
+intercepted packets in an effort to confuse or subvert the receiver. Complete
+protection is not possible since it is necessary to handle legitmate packets
+which are lost, duplicated, or delivered out of order, but use of sequence
+numbers makes the attack much more difficult.</p>
+
+<p>The RFCs require that sequence numbers never cycle, that a new key always
+be negotiated before the sequence number reaches 2^32-1. This protects both
+against replays attacks using packets from a previous cyclce and against <a
+href="glossary.html#birthday">birthday attacks</a> on the the packet
+authentication algorithm.</p>
+
+<p>In Linux FreeS/WAN, the sequence number is ignored for manually keyed
+connections and checked for automatically keyed ones. In manual mode, there
+is no way to negotiate a new key, or to recover from a sequence number
+problem, so we don't use sequence numbers.</p>
+
+<h3><a name="ESP.ipsec">Encapsulated Security Payload (ESP)</a></h3>
+
+<p>The ESP protocol is defined in RFC 2406. It provides one or both of
+encryption and packet authentication. It may be used with or without AH
+packet authentication.</p>
+
+<p>Note that <strong>some form of packet authentication should
+<em>always</em> be used whenever data is encrypted</strong>. Without
+authentication, the encryption is vulnerable to active attacks which may
+allow an enemy to break the encryption. ESP should <strong>always</strong>
+either include its own authentication or be used with AH authentication.</p>
+
+<p>The RFCs require support for only two mandatory encryption algorithms --
+<a href="glossary.html#DES">DES</a>, and null encryption -- and for two
+authentication methods -- keyed MD5 and keyed SHA. Implementers may choose to
+support additional algorithms in either category.</p>
+
+<p>The authentication algorithms are the same ones used in the IPsec <a
+href="#AH">authentication header</a>.</p>
+
+<p>We do not implement single DES since <a
+href="politics.html#desnotsecure">DES is insecure</a>. Instead we provide <a
+href="glossary.html#3DES">triple DES or 3DES</a>. This is currently the only
+encryption algorithm supported.</p>
+
+<p>We do not implement null encryption since it is obviously insecure.</p>
+
+<h2><a name="modes">IPsec modes</a></h2>
+
+<p>IPsec can connect in two modes. Transport mode is a host-to-host
+connection involving only two machines. In tunnel mode, the IPsec machines
+act as gateways and trafiic for any number of client machines may be
+carried.</p>
+
+<h3><a name="tunnel.ipsec">Tunnel mode</a></h3>
+
+<p>Security gateways are required to support tunnel mode connections. In this
+mode the gateways provide tunnels for use by client machines behind the
+gateways. The client machines need not do any IPsec processing; all they have
+to do is route things to gateways.</p>
+
+<h3><a name="transport.ipsec">Transport mode</a></h3>
+
+<p>Host machines (as opposed to security gateways) with IPsec implementations
+must also support transport mode. In this mode, the host does its own IPsec
+processing and routes some packets via IPsec.</p>
+
+<h2><a name="parts">FreeS/WAN parts</a></h2>
+
+<h3><a name="KLIPS.ipsec">KLIPS: Kernel IPsec Support</a></h3>
+
+<p>KLIPS is <strong>K</strong>erne<strong>L</strong> <strong>IP</strong>SEC
+<strong>S</strong>upport, the modifications necessary to support IPsec within
+the Linux kernel. KILPS does all the actual IPsec packet-handling,
+including</p>
+<ul>
+  <li>encryption</li>
+  <li>packet authentication calculations</li>
+  <li>creation of ESP and AH headers for outgoing packets</li>
+  <li>interpretation of those headers on incoming packets</li>
+</ul>
+
+<p>KLIPS also checks all non-IPsec packets to ensure they are not bypassing
+IPsec security policies.</p>
+
+<h3><a name="Pluto.ipsec">The Pluto daemon</a></h3>
+
+<p><a href="manpage.d/ipsec_pluto.8.html">Pluto(8)</a> is a daemon which
+implements the IKE protocol. It</p>
+<ul>
+  <li>handles all the Phase one ISAKMP SAs</li>
+  <li>performs host authentication and negotiates with other gateways</li>
+  <li>creates IPsec SAs and passes the data required to run them to KLIPS</li>
+  <li>adjust routing and firewall setup to meet IPsec requirements. See our
+    <a href="firewall.html">IPsec and firewalling</a> document for
+  details.</li>
+</ul>
+
+<p>Pluto is controlled mainly by the <a
+href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a> configuration file.</p>
+
+<h3><a name="command">The ipsec(8) command</a></h3>
+
+<p>The <a href="manpage.d/ipsec.8.html">ipsec(8)</a> command is a front end
+shellscript that allows control over IPsec activity.</p>
+
+<h3><a name="ipsec.conf">Linux FreeS/WAN configuration file</a></h3>
+
+<p>The configuration file for Linux FreeS/WAN is</p>
+<pre>        /etc/ipsec.conf</pre>
+
+<p>For details see the <a
+href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a> manual page .</p>
+
+<h2><a name="key">Key management</a></h2>
+
+<p>There are several ways IPsec can manage keys. Not all are implemented in
+Linux FreeS/WAN.</p>
+
+<h3><a name="current">Currently Implemented Methods</a></h3>
+
+<h4><a name="manual">Manual keying</a></h4>
+
+<p>IPsec allows keys to be manually set. In Linux FreeS/WAN, such keys are
+stored with the connection definitions in /etc/ipsec.conf.</p>
+
+<p><a href="glossary.html#manual">Manual keying</a> is useful for debugging
+since it allows you to test the <a href="glossary.html#KLIPS">KLIPS</a>
+kernel IPsec code without the <a href="glossary.html#Pluto">Pluto</a> daemon
+doing key negotiation.</p>
+
+<p>In general, however, automatic keying is preferred because it is more
+secure.</p>
+
+<h4><a name="auto">Automatic keying</a></h4>
+
+<p>In automatic keying, the <a href="glossary.html#Pluto">Pluto</a> daemon
+negotiates keys using the <a href="glossary.html#IKE">IKE</a> Internet Key
+Exchange protocol. Connections are automatically re-keyed periodically.</p>
+
+<p>This is considerably more secure than manual keying. In either case an
+attacker who acquires a key can read every message encrypted with that key,
+but automatic keys can be changed every few hours or even every few minutes
+without breaking the connection or requiring intervention by the system
+administrators. Manual keys can only be changed manually; you need to shut
+down the connection and have the two admins make changes. Moreover, they have
+to communicate the new keys securely, perhaps with <a
+href="glossary.html#PGP">PGP</a> or <a href="glossary.html#SSH">SSH</a>. This
+may be possible in some cases, but as a general solution it is expensive,
+bothersome and unreliable. Far better to let <a
+href="glossary.html#Pluto">Pluto</a> handle these chores; no doubt the
+administrators have enough to do.</p>
+
+<p>Also, automatic keying is inherently more secure against an attacker who
+manages to subvert your gateway system. If manual keying is in use and an
+adversary acquires root privilege on your gateway, he reads your keys from
+/etc/ipsec.conf and then reads all messages encrypted with those keys.</p>
+
+<p>If automatic keying is used, an adversary with the same privileges can
+read /etc/ipsec.secrets, but this does not contain any keys, only the secrets
+used to authenticate key exchanges. Having an adversary able to authenticate
+your key exchanges need not worry you overmuch. Just having the secrets does
+not give him any keys. You are still secure against <a
+href="glossary.html#passive">passive</a> attacks. This property of automatic
+keying is called <a href="glossary.html#PFS">perfect forward secrecy</a>,
+abbreviated PFS.</p>
+
+<p>Unfortunately, having the secrets does allow an <a
+href="glossary.html#active">active attack</a>, specifically a <a
+href="glossary.html#middle">man-in-the-middle</a> attack. Losing these
+secrets to an attacker may not be quite as disastrous as losing the actual
+keys, but it is <em>still a serious security breach</em>. These secrets
+should be guarded as carefully as keys.</p>
+
+<h3><a name="notyet">Methods not yet implemented</a></h3>
+
+<h4><a name="noauth">Unauthenticated key exchange</a></h4>
+
+<p>It would be possible to exchange keys without authenticating the players.
+This would support <a href="glossary.html#carpediem">opportunistic
+encryption</a> -- allowing any two systems to encrypt their communications
+without requiring a shared PKI or a previously negotiated secret -- and would
+be secure against <a href="glossary.html#passive">passive attacks</a>. It
+would, however, be highly vulnerable to active <a
+href="glossary.html#middle">man-in-the-middle</a> attacks. RFC 2408 therefore
+specifies that all <a href="glossary.html#ISAKMP">ISAKMP</a> key management
+interactions <em>must</em> be authenticated.</p>
+
+<p>There is room for debate here. Should we provide immediate security
+against <a href="glossary.html#passive">passive attacks</a> and encourage
+widespread use of encryption, at the expense of risking the more difficult <a
+href="glossary.html#active">active attacks</a>? Or should we wait until we
+can implement a solution that can both be widespread and offer security
+against active attacks?</p>
+
+<p>So far, we have chosen the second course, complying with the RFCs and
+waiting for secure DNS (see <a href="glossary.html#DNS">below</a>) so that we
+can do <a href="glossary.html#carpediem">opportunistic encryption</a>
+right.</p>
+
+<h4><a name="DNS">Key exchange using DNS</a></h4>
+
+<p>The IPsec RFCs allow key exchange based on authentication services
+provided by <a href="glossary.html#SDNS">Secure DNS</a>. Once Secure DNS
+service becomes widely available, we expect to make this the <em>primary key
+management method for Linux FreeS/WAN</em>. It is the best way we know of to
+support <a href="glossary.html#carpediem">opportunistic encryption</a>,
+allowing two systems without a common PKI or previous negotiation to secure
+their communication.</p>
+
+<p>We currently have code to acquire RSA keys from DNS but do not yet have
+code to validate Secure DNS signatures.</p>
+
+<h4><a name="PKI">Key exchange using a PKI</a></h4>
+
+<p>The IPsec RFCs allow key exchange based on authentication services
+provided by a <a href="glossary.html#PKI">PKI</a> or Public Key
+Infrastructure. With many vendors selling such products and many large
+organisations building these infrastructures, this will clearly be an
+important application of IPsec and one Linux FreeS/WAN will eventually
+support.</p>
+
+<p>On the other hand, this is not as high a priority for Linux FreeS/WAN as
+solutions based on <a href="glossary.html#SDNS">secure DNS</a>. We do not
+expect any PKI to become as universal as DNS.</p>
+
+<p>Some <a href="web.html#patch">patches</a> to handle authentication with
+X.509 certificates, which most PKIs use, are available.</p>
+
+<h4><a name="photuris">Photuris</a></h4>
+
+<p><a href="glossary.html#photuris">Photuris</a> is another key management
+protocol, an alternative to IKE and ISAKMP, described in RFCs 2522 and 2523
+which are labelled "experimental". Adding Photuris support to Linux FreeS/WAN
+might be a good project for a volunteer. The likely starting point would be
+the OpenBSD photurisd code.</p>
+
+<h4><a name="skip">SKIP</a></h4>
+
+<p><a href="glossary.html#SKIP">SKIP</a> is yet another key management
+protocol, developed by Sun. At one point it was fairly widely used, but it
+now seems moribund, displaced by IKE. Sun now (as of Solaris 8.0) ship an
+IPsec implementation using IKE. We have no plans to implement SKIP. If a user
+were to implement it, we would almost certainly not want to add the code to
+our distribution.</p>
+</body>
+</html>
diff --git a/doc/src/kernel.html b/doc/src/kernel.html
new file mode 100644
index 000000000..a4beab417
--- /dev/null
+++ b/doc/src/kernel.html
@@ -0,0 +1,392 @@
+<html>
+<head>
+<title>Kernel configuration for FreeS/WAN</title>
+<meta name="keywords" content="Linux, IPsec, VPN, security, FreeSWAN, kernel">
+
+<!--
+
+Written by Sandy Harris for the Linux FreeS/WAN project
+Freely distributable under the GNU General Public License
+
+More information at www.freeswan.org
+Feedback to users@lists.freeswan.org
+
+CVS information:
+RCS ID:          $Id: kernel.html,v 1.1 2004/03/15 20:35:24 as Exp $
+Last changed:    $Date: 2004/03/15 20:35:24 $
+Revision number: $Revision: 1.1 $
+
+CVS revision numbers do not correspond to FreeS/WAN release numbers.
+-->
+</head>
+
+<body>
+
+<h1><a name="kernelconfig">Kernel configuration for FreeS/WAN</a></h1>
+
+<p>
+This section lists many of the options available when configuring a Linux
+  kernel, and explains how they should be set on a FreeS/WAN IPsec
+  gateway.</p>
+
+  <h2><a name="notall">Not everyone needs to worry about kernel configuration</a></h2>
+
+  <p>Note that in many cases you do not need to mess with these.</p>
+
+<p>
+You may have a Linux distribution which comes with FreeS/WAN installed
+(see this <a href="intro.html#products">list</a>).
+  In that case, you need not do a FreeS/WAN installation or a kernel
+  configuration. Of course, you might still want to configure and rebuild your
+  kernel to improve performance or security. This can be done with standard
+  tools described in the <a href="http://www.linuxdoc.org/HOWTO/Kernel-HOWTO.html">Kernel HowTo</a>.</p>
+
+  <p>If you need to install FreeS/WAN, then you do need to configure a kernel.
+  However, you may choose to do that using the simplest procedure:</p>
+  <ul>
+    <li>Configure, build and test a kernel for your system before adding FreeS/WAN. See the <a
+      href="http://www.linuxdoc.org/HOWTO/Kernel-HOWTO.html">Kernel HowTo</a> for details. <strong>This step cannot be
+      skipped</strong>. FreeS/WAN needs the results of your configuration.</li>
+    <li>Then use FreeS/WAN's <var>make oldgo</var> command. This sets
+      everything FreeS/WAN needs and retains your values everywhere else.</li>
+  </ul>
+
+<p>
+This document is for those who choose to configure their FreeS/WAN kernel
+themselves.</p>
+
+<h2><a name="assume">Assumptions and notation</a></h2>
+
+<p>
+Help text for most kernel options is included with the kernel files, and
+is accessible from within the configuration utilities. We assume
+you will refer to that, and to the <a href="http://www.linuxdoc.org/HOWTO/Kernel-HOWTO.html">Kernel HowTo</a>, as
+necessary. This document covers only the FreeS/WAN-specific aspects of the
+problem.</p>
+
+<p>
+To avoid duplication, this document section does not cover settings for
+the additional IPsec-related kernel options which become available after you
+have patched your kernel with FreeS/WAN patches. There is help text for
+those available from within the configuration utility.</p>
+
+  <p>
+We assume a common configuration in which the FreeS/WAN IPsec gateway is
+also doing ipchains(8) firewalling for a local network, and possibly
+masquerading as well.</p>
+
+<p>
+Some suggestions below are labelled as appropriate for "a true paranoid".
+By this we mean they may cause inconvenience and it is not entirely clear
+  they are necessary, but they appear to be the safest choice. Not using them
+  might entail some risk. Of course one suggested mantra for security
+  administrators is: "I know I'm paranoid. I wonder if I'm paranoid
+  enough."</p>
+
+  <h3><a name="labels">Labels used</a></h3>
+
+<p>
+Six labels are used to indicate how options should be set. We mark the
+labels with [square brackets]. For two of these labels, you have no
+choice:</p>
+  <dl>
+    <dt>[required]</dt>
+      <dd>essential for FreeS/WAN operation.</dd>
+    <dt>[incompatible]</dt>
+      <dd>incompatible with FreeS/WAN.</dd>
+  </dl>
+
+  <p>those must be set correctly or FreeS/WAN will not work</p>
+
+  <p>FreeS/WAN should work with any settings of the others, though of course
+  not all combinations have been tested. We do label these in various ways,
+  but <em>these labels are only suggestions</em>.</p>
+  <dl>
+    <dt>[recommended]</dt>
+      <dd>useful on most FreeS/WAN gateways</dd>
+    <dt>[disable]</dt>
+      <dd>an unwelcome complication on a FreeS/WAN gateway.</dd>
+    <dt>[optional]</dt>
+      <dd>Your choice. We outline issues you might consider.</dd>
+    <dt>[anything]</dt>
+      <dd>This option has no direct effect on FreeS/WAN and related tools, so
+        you should be able to set it as you please.</dd>
+  </dl>
+
+<p>
+Of course complexity is an enemy in any effort to build secure systems.
+<strong>For maximum security, any feature that can reasonably be turned off
+should be</strong>. "If in doubt, leave it out."</p>
+  
+  <h2><a name="kernelopt">Kernel options for FreeS/WAN</a></h2>
+
+<p>
+Indentation is based on the nesting shown by 'make menuconfig' with a
+2.2.16 kernel for the i386 architecture.</p>
+<dl>
+    <dt><a name="maturity">Code maturity and level options</a></dt>
+      <dd>
+      <dl>
+          <dt><a name="devel">Prompt for development ...
+          code/drivers</a></dt>
+            <dd>[optional] If this is <var>no</var>, experimental drivers are
+              not shown in later menus.
+              <p>For most FreeS/WAN work, <var>no</var> is the preferred
+              setting. Using new or untested components is too risky for a
+              security gateway.</p>
+              <p>However, for some hardware (such as the author's network
+              cards) the only drivers available are marked
+              <var>new/experimental</var>. In such cases, you must enable this
+              option or your cards will not appear under &quot;network device
+              support&quot;. A true paranoid would leave this option off and
+              replace the cards.</p>
+            </dd>
+        <dt>Processor type and features</dt>
+            <dd>[anything]</dd>
+          <dt>Loadable module support</dt>
+      <dd>
+      <dl>
+          <dt>Enable loadable module support</dt>
+            <dd>[optional] A true paranoid would disable this. An attacker who
+              has root access to your machine can fairly easily install a
+              bogus module that does awful things, provided modules are
+              enabled. A common tool for attackers is a &quot;rootkit&quot;, a set
+              of tools the attacker uses once he or she has become root on your system.
+              The kit introduces assorted additional compromises so that the attacker
+              will continue to &quot;own&quot; your system despite most things you might
+              do to recovery the situation. For Linux, there is a tool called
+              <a href="http://www.sans.org/newlook/resources/IDFAQ/knark.htm">knark</a>
+              which is basically a rootkit packaged as a kernel module.
+              <p>With modules disabled, an attacker cannot install a bogus module.
+              The only way
+              he can achieve the same effects is to install a new kernel and
+              reboot. This is considerably more likely to be noticed.
+              <p>Many FreeS/WAN gateways run with modules enabled. This
+              simplifies some administrative tasks and some ipchains features
+              are available only as modules. Once an enemy has root on your
+              machine your security is nil, so arguably defenses which come
+              into play only in that situation are pointless.</p>
+              <p>
+             
+            </dd>
+          <dt>Set version information ....</dt>
+            <dd>[optional] This provides a check to prevent loading modules
+              compiled for a different kernel.</dd>
+          <dt>Kernel module loader</dt>
+            <dd>[disable] It gives little benefit on a typical FreeS/WAN gate
+              and entails some risk.</dd>
+        </dl>
+      </dd>
+    <dt>General setup</dt>
+      <dd>We list here only the options that matter for FreeS/WAN.
+        <dl>
+          <dt>Networking support</dt>
+            <dd>[required]</dd>
+          <dt>Sysctl interface</dt>
+            <dd>[optional] If this option is turned on and the
+              <var>/proc</var> filesystem installed, then you can control
+              various system behaviours by writing to files under
+              <var>/proc/sys</var>. For example:
+              <pre>        echo 1 &gt; /proc/sys/net/ipv4/ipforward</pre>
+              turns IP forwarding on.
+              <p>Disabling this option breaks many firewall scripts. A true
+              paranoid would disable it anyway since it might conceivably be
+              of use to an attacker.</p>
+            </dd>
+        </dl>
+      </dd>
+    <dt>Plug and Play support</dt>
+      <dd>[anything]</dd>
+    <dt>Block devices</dt>
+      <dd>[anything]</dd>
+    <dt>Networking options</dt>
+      <dd>
+      <dl>
+          <dt>Packet socket</dt>
+            <dd>[optional] This kernel feature supports tools such as
+              tcpdump(8) which communicate directly with network hardware,
+              bypassing kernel protocols. This is very much a two-edged sword:
+              <ul>
+                <li>such tools can be very useful to the firewall admin,
+                  especially during initial testing</li>
+                <li>should an evildoer breach your firewall, such tools could
+                  give him or her a great deal of information about the rest
+                  of your network</li>
+              </ul>
+              We recommend disabling this option on production gateways.</dd>
+          <dt><a name="netlink">Kernel/User netlink socket</a></dt>
+            <dd>[optional] Required if you want to use <a href="#adv">advanced
+              router</a> features.</dd>
+          <dt>Routing messages</dt>
+            <dd>[optional]</dd>
+          <dt>Netlink device emulation</dt>
+            <dd>[optional]</dd>
+          <dt>Network firewalls</dt>
+            <dd>[recommended] You need this if the IPsec gateway also
+              functions as a firewall.
+              <p>Even if the IPsec gateway is not your primary firewall, we
+              suggest setting this so that you can protect the gateway with at
+              least basic local packet filters.</p>
+            </dd>
+          <dt>Socket filtering</dt>
+            <dd>[disable] This enables an older filtering interface. We suggest
+                using ipchains(8) instead. To do that, set the &quot;Network
+                firewalls&quot; option just above, and not this one.</dd>
+          <dt>Unix domain sockets</dt>
+            <dd>[required] These sockets are used for communication between the
+              <a href="manpage.d/ipsec.8.html">ipsec(8)</a>
+              commands and the <a href="manpage.d/ipsec_pluto.8.html">ipsec_pluto(8)</a>
+              daemon.</dd>
+          <dt>TCP/IP networking</dt>
+            <dd>[required]
+              <dl>
+                <dt>IP: multicasting</dt>
+                  <dd>[anything]</dd>
+                <dt><a name="adv">IP: advanced router</a></dt>
+                  <dd>[optional] This gives you policy routing, which some
+                    people have used to good advantage in their scripts for
+                    FreeS/WAN gateway management. It is not used in our
+                    distributed scripts, so not required unless you want it
+                    for custom scripts. It requires the <a
+                    href="#netlink">netlink</a> interface between kernel code
+                    and the iproute2(8) command.</dd>
+                <dt>IP: kernel level autoconfiguration</dt>
+                  <dd>[disable] It gives little benefit on a typical FreeS/WAN
+                    gate and entails some risk.</dd>
+                <dt>IP: firewall packet netlink device</dt>
+                  <dd>[disable]</dd>
+                <dt>IP: transparent proxy support</dt>
+                  <dd>[optional] This is required in some firewall configurations,
+                    but should be disabled unless you have a definite need for it.
+                    </dd>
+                <dt>IP: masquerading</dt>
+                  <dd>[optional] Required if you want to use
+                    <a href="glossary.html#non-routable">non-routable</a> private
+                     IP addresses for your local network.</dd>
+                <dt>IP: Optimize as router not host</dt>
+                  <dd>[recommended]</dd>
+                <dt>IP: tunneling</dt>
+                  <dd>[required]</dd>
+                <dt>IP: GRE tunnels over IP</dt>
+                  <dd>[anything]</dd>
+                <dt>IP: aliasing support</dt>
+                  <dd>[anything]</dd>
+                <dt>IP: ARP daemon support (EXPERIMENTAL)</dt>
+                  <dd>Not required on most systems, but might prove useful on
+                    heavily-loaded gateways.</dd>
+                <dt>IP: TCP syncookie support</dt>
+                  <dd>[recommended] It provides a defense against a <a
+                    href="glossary.html#DOS">denial of
+                    service attack</a> which uses bogus TCP connection
+                    requests to waste resources on the victim machine.</dd>
+                <dt>IP: Reverse ARP</dt>
+                  <dd></dd>
+                <dt>IP: large window support</dt>
+                  <dd>[recommended] unless you have less than 16 meg RAM</dd>
+              </dl>
+            </dd>
+          <dt>IPv6</dt>
+            <dd>[optional] FreeS/WAN does not currently support IPv6, though work on
+              integrating FreeS/WAN with the Linux IPv6 stack has begun.
+              <a href="compat.html#ipv6">Details</a>.
+              <p>
+              It should be possible to use IPv4 FreeS/WAN on a machine which also
+              does IPv6. This combination is not yet well tested. We would be quite
+              interested in hearing results from anyone expermenting with it, via the
+              <a href="mail.html">mailing list</a>.
+              <p>
+              We do not recommend using IPv6 on production FreeS/WAN gateways until
+              more testing has been done.
+              </dd>
+          <dt>Novell IPX</dt>
+            <dd>[disable]</dd>
+          <dt>Appletalk</dt>
+            <dd>[disable] Quite a few Linux installations use IP but also have
+              some other protocol, such as Appletalk or IPX, for communication
+              with local desktop machines. In theory it should be possible to
+              configure IPsec for the IP side of things without interfering
+              with the second protocol.
+              <p>We do not recommend this. Keep the software on your gateway
+              as simple as possible. If you need a Linux-based Appletalk or
+              IPX server, use a separate machine.</p>
+            </dd>
+        </dl>
+      </dd>
+    <dt>Telephony support</dt>
+      <dd>[anything]</dd>
+    <dt>SCSI support</dt>
+      <dd>[anything]</dd>
+    <dt>I2O device support</dt>
+      <dd>[anything]</dd>
+    <dt>Network device support</dt>
+      <dd>[anything] should work, but there are some points to note.
+        <p>The development team test almost entirely on 10 or 100 megabit
+        Ethernet and modems. In principle, any device that can do IP should be
+        just fine for IPsec, but in the real world any device that has not
+        been well-tested is somewhat risky. By all means try it, but don't bet
+        your project on it until you have solid test results.</p>
+        <p>If you disabled experimental drivers in the <a
+        href="#maturity">Code maturity</a> section above, then those drivers
+        will not be shown here. Check that option before going off to hunt for
+        missing drivers.</p>
+        <p>If you want Linux to automatically find more than one ethernet
+        interface at boot time, you need to:</p>
+        <ul>
+          <li>compile the appropriate driver(s) into your kernel. Modules will
+            not work for this</li>
+          <li>add a line such as
+<pre>
+   append="ether=0,0,eth0 ether=0,0,eth1"
+</pre>
+            to your /etc/lilo.conf file. In some cases you may need to specify
+            parameters such as IRQ or base address. The example uses &quot;0,0&quot;
+            for these, which tells the system to search. If the search does not
+            succeed on your hardware, then you should retry with explicit parameters.
+            See the lilo.conf(5) man page for details.</li>
+          <li>run lilo(8)</li>
+        </ul>
+        Having Linux find the cards this way is not necessary, but is usually more
+        convenient than loading modules in your boot scripts.</dd>
+    <dt>Amateur radio support</dt>
+      <dd>[anything]</dd>
+    <dt>IrDA (infrared) support</dt>
+      <dd>[anything]</dd>
+    <dt>ISDN subsystem</dt>
+      <dd>[anything]</dd>
+    <dt>Old CDROM drivers</dt>
+      <dd>[anything]</dd>
+    <dt>Character devices</dt>
+      <dd>The only required character device is:
+        <dl>
+          <dt>random(4)</dt>
+            <dd>[required] This is a source of <a href="glossary.html#random">random</a>
+              numbers which are required for many cryptographic protocols,
+              including several used in IPsec.
+              <p>If you are comfortable with C source code, it is likely a
+              good idea to go in and adjust the <var>#define</var> lines in
+              <var>/usr/src/linux/drivers/char/random.c</var> to ensure that
+              all sources of randomness are enabled. Relying solely on
+              keyboard and mouse randomness is dubious procedure for a gateway
+              machine. You could also increase the randomness pool size from
+              the default 512 bytes (128 32-bit words).</p>
+            </dd>
+        </dl>
+     <dt>Filesystems</dt>
+       <dd>[anything] should work, but we suggest limiting a gateway
+         machine to the standard Linux ext2 filesystem in most
+         cases.</dd>
+     <dt>Network filesystems</dt>
+       <dd>[disable] These systems are an unnecessary risk on an IPsec
+         gateway.</dd>
+     <dt>Console drivers</dt>
+            <dd>[anything]</dd>
+     <dt>Sound</dt>
+       <dd>[anything] should work, but we suggest enabling sound only if
+              you plan to use audible alarms for firewall problems.</dd>
+     <dt>Kernel hacking</dt>
+       <dd>[disable] This might be enabled on test machines, but should
+         not be on production gateways.</dd>
+   </dl>
+  </dl>
+</body>
+</html>
diff --git a/doc/src/mail.html b/doc/src/mail.html
new file mode 100644
index 000000000..e26f025a0
--- /dev/null
+++ b/doc/src/mail.html
@@ -0,0 +1,250 @@
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>FreeS/WAN mailing lists</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, FreeSWAN, mailing, list">
+  <!--
+
+  Written by Sandy Harris for the Linux FreeS/WAN project
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: mail.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+
+<body>
+<h1><a name="lists">Mailing lists and newsgroups</a></h1>
+
+<h2><a name="list.fs">Mailing lists about FreeS/WAN</a></h2>
+
+<h3><a name="projlist">The project mailing lists</a></h3>
+
+<p>The Linux FreeS/WAN project has several email lists for user support, bug
+reports and software development discussions.</p>
+
+<p>We had a single list on clinet.fi for several years (Thanks, folks!), then
+one list on freeswan.org, but now we've split into several lists:</p>
+<dl>
+  <dt><a
+  href="mailto:users-request@lists.freeswan.org?body=subscribe">users</a></dt>
+    <dd><ul>
+        <li>The general list for discussing use of the software</li>
+        <li>The place for seeking <strong>help with problems</strong> (but
+          please check the <a href="faq.html">FAQ</a> first).</li>
+        <li>Anyone can post.</li>
+      </ul>
+    </dd>
+  <dt><a
+  href="mailto:bugs-request@lists.freeswan.org?body=subscribe">bugs</a></dt>
+    <dd><ul>
+        <li>For <strong>bug reports</strong>.</li>
+        <li>If you are not certain what is going on -- could be a bug, a
+          configuration error, a network problem, ... -- please post to the
+          users list instead.</li>
+        <li>Anyone can post.</li>
+      </ul>
+    </dd>
+  <dt><a
+  href="mailto:design-request@lists.freeswan.org?body=subscribe">design</a></dt>
+    <dd><ul>
+        <li><strong>Design discussions</strong>, for people working on
+          FreeS/WAN development or others with an interest in design and
+          security issues.</li>
+        <li>It would be a good idea to read the existing design papers (see
+          this <a href="intro.html#applied">list</a>) before posting.</li>
+        <li>Anyone can post.</li>
+      </ul>
+    </dd>
+  <dt><a
+  href="mailto:announce-request@lists.freeswan.org?body=subscribe">announce</a></dt>
+    <dd><ul>
+        <li>A <strong>low-traffic</strong> list.</li>
+        <li><strong>Announcements</strong> about FreeS/WAN and related
+          software.</li>
+        <li>All posts here are also sent to the users list. You need not
+          subscribe to both.</li>
+        <li>Only the FreeS/WAN team can post.</li>
+        <li>If you have something you feel should go on this list, send it to
+          <var>announce-admin@lists.freeswan.org</var>. Unless it is obvious,
+          please include a short note explaining why we should post it.</li>
+      </ul>
+    </dd>
+  <dt><a
+  href="mailto:briefs-request@lists.freeswan.org?body=subscribe">briefs</a></dt>
+    <dd><ul>
+        <li>A <strong>low-traffic</strong> list.</li>
+        <li><strong>Weekly summaries</strong> of activity on the users
+        list.</li>
+        <li>All posts here are also sent to the users list. You need not
+          subscribe to both.</li>
+        <li>Only the FreeS/WAN team can post.</li>
+      </ul>
+    </dd>
+</dl>
+
+<p>To subscribe to any of these, you can:</p>
+<ul>
+  <li>just follow the links above</li>
+  <li>use our <a href="http://www.freeswan.org/mail.html">web
+  interface</a></li>
+  <li>send mail to <var>listname</var>-request@lists.freeswan.org with a
+    one-line message body "subscribe"</li>
+</ul>
+
+<p>Archives of these lists are available via the <a
+href="http://www.freeswan.org/mail.html">web interface</a>.</p>
+
+<h4><a name="which.list">Which list should I use?</a></h4>
+
+<p>For most questions, please check the <a href="faq.html">FAQ</a> first, and
+if that does not have an answer, ask on the users list. "My configuration
+doesn't work." does not belong on the bugs list, and "Can FreeS/WAN do
+such-and-such" or "How do I configure it to..." do not belong in design
+discussions.</p>
+
+<p>Cross-posting the same message to two or more of these lists is
+discouraged. Quite a few people read more than one list and getting multiple
+copies is annoying.</p>
+
+<h4><a name="policy.list">List policies</a></h4>
+
+<p><strong>US citizens or residents are asked not to post code to the lists,
+not even one-line bug fixes</strong>. The project cannot accept code which
+might entangle it in US <a href="politics.html#exlaw">export
+restrictions</a>.</p>
+
+<p>Non-subscribers can post to some of these lists. This is necessary;
+someone working on a gateway install who encounters a problem may not have
+access to a subscribed account.</p>
+
+<p>Some spam turns up on these lists from time to time. For discussion of why
+we do not attempt to filter it, see the <a href="faq.html#spam">FAQ</a>.
+Please do not clutter the lists with complaints about this.</p>
+
+<h3><a name="archive">Archives of the lists</a></h3>
+
+<p>Searchable archives of the old single list have existed for some time. At
+time of writing, it is not yet clear how they will change for the new
+multi-list structure.</p>
+<ul>
+  <li><a href="http://www.sandelman.ottawa.on.ca/linux-ipsec">Canada</a></li>
+  <li><a href="http://www.nexial.com">Holland</a></li>
+</ul>
+
+<p>Note that these use different search engines. Try both.</p>
+
+<p>Archives of the new lists are available via the <a
+href="http://www.freeswan.org/mail.html">web interface</a>.</p>
+
+<h2><a name="indexes">Indexes of mailing lists</a></h2>
+
+<p><a href="http://paml.net/">PAML</a> is the standard reference for
+<strong>P</strong>ublicly <strong>A</strong>ccessible
+<strong>M</strong>ailing <strong>L</strong>ists. When we last checked, it had
+over 7500 lists on an amazing variety of topics. It also has FAQ information
+and a search engine.</p>
+
+<p>There is an index of <a
+href="http://oslab.snu.ac.kr/~djshin/linux/mail-list/index.shtml">Linux
+mailing lists</a> available.</p>
+
+<p>A list of <a
+href="http://xforce.iss.net/maillists/otherlists.php">computer security
+mailing lists</a>, with descriptions.</p>
+
+<h2><a name="otherlists">Lists for related software and topics</a></h2>
+
+<p>Most links in this section point to subscription addresses for the various
+lists. Send the one-line message "subscribe <var>list_name</var>" to
+subscribe to any of them.</p>
+
+<h3>Products that include FreeS/WAN</h3>
+
+<p>Our introduction document gives a <a href="intro.html#products">list of
+products that include FreeS/WAN</a>. If you have, or are considering, one of
+those, check the supplier's web site for information on mailing lists for
+their users.</p>
+
+<h3><a name="linux.lists">Linux mailing lists</a></h3>
+<ul>
+  <li><a
+    href="mailto:majordomo@vger.kernel.org">linux-admin@vger.kernel.org</a>,
+    for Linux system administrators</li>
+  <li><a
+    href="mailto:netfilter-request@lists.samba.org">netfilter@lists.samba.org</a>,
+    about Netfilter, which replaces IPchains in kernels 2.3.15 and later</li>
+  <li><a
+    href="mailto:security-audit-request@ferret.lmh.ox.ac.uk">security-audit@ferret.lmh.ox.ac.uk</a>,
+    for people working on security audits of various Linux programs</li>
+  <li><a
+    href="mailto:securedistros-request@humbolt.geo.uu.nl">securedistros@humbolt.geo.uu.nl</a>,
+    for discussion of issues common to all the half dozen projects working on
+    secure Linux distributions.</li>
+</ul>
+
+<p>Each of the scure distribution projects also has its own web site and
+mailing list. Some of the sites are:</p>
+<ul>
+  <li><a href="http://bastille-linux.org/">Bastille Linux</a> scripts to
+    harden Redhat, e.g. by changing permissions and modifying inialisation
+    scripts</li>
+  <li><a href="http://immunix.org/">Immunix</a> take a different approach,
+    using a modified compiler to build kernel and utilities with better
+    resistance to various types of overflow and exploit</li>
+  <li>the <a href="glossary.html#NSA">NSA</a> have contractors working on a
+    <a href="glossary.html#SElinux">Security Enhanced Linux</a>, primarily
+    adding stronger access control mechanisms. You can download the current
+    version (which interestingly is under GPL and not export resrtricted) or
+    subscribe to the mailing list from the <a
+    href="http://www.nsa.gov/selinux">project web page</a>.</li>
+</ul>
+
+<h3><a name="ietf">Lists for IETF working groups</a></h3>
+
+<p>Each <a href="glossary.html#IETF">IETF</a> working group has an associated
+mailing list where much of the work takes place.</p>
+<ul>
+  <li><a
+    href="mailto:majordomo@lists.tislabs.com">ipsec@lists.tislabs.com</a>,
+    the IPsec <a
+    href="http://www.ietf.org/html.charters/ipsec-charter.html">working
+    group</a>. This is where the protocols are discussed, new drafts
+    announced, and so on. By now, the IPsec working group is winding down
+    since the work is essentially complete. A <a
+    href="http://www.sandelman.ottawa.on.ca/ipsec/">list archive</a> is
+    available.</li>
+  <li><a href="mailto:ipsec-policy-request@vpnc.org">IPsec policy</a> list,
+    and its <a href="http://www.vpnc.org/ipsec-policy/">archive</a></li>
+  <li><a href="mailto:ietf-ipsra-request@vpnc.org">IP secure remote
+    access</a> list, and its <a
+    href="http://www.vpnc.org/ietf-ipsra/mail-archive/">archive</a></li>
+</ul>
+
+<h3><a name="other">Other mailing lists</a></h3>
+<ul>
+  <li><a
+    href="mailto:ipc-announce-request@privacy.org">ipc-announce@privacy.org</a>
+    a low-traffic list with announcements of developments in privacy,
+    encryption and online civil rights</li>
+  <li>a VPN mailing list's <a
+    href="http://kubarb.phsx.ukans.edu/~tbird/vpn.html">home page</a></li>
+</ul>
+
+<h2><a name="newsgroups">Usenet newsgroups</a></h2>
+<ul>
+  <li>sci.crypt</li>
+  <li>sci.crypt.research</li>
+  <li>comp.dcom.vpn</li>
+  <li>talk.politics.crypto</li>
+</ul>
+</body>
+</html>
diff --git a/doc/src/makecheck.html b/doc/src/makecheck.html
new file mode 100644
index 000000000..7fa3a3bcb
--- /dev/null
+++ b/doc/src/makecheck.html
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+<html>
+<head>
+<title>FreeS/WAN "make check" guide</title>
+<!-- Changed by: Michael Richardson, 02-Apr-2003 -->
+<meta name="keywords" content="Linux, IPsec, VPN, security, FreeSWAN, testing, User-Mode-Linux, UML">
+
+<!--
+
+Written by Michael Richardson for the Linux FreeS/WAN project
+Freely distributable under the GNU General Public License
+
+More information at www.freeswan.org
+Feedback to users@lists.freeswan.org
+
+$Id: makecheck.html,v 1.1 2004/03/15 20:35:24 as Exp $
+
+$Log: makecheck.html,v $
+Revision 1.1  2004/03/15 20:35:24  as
+added files from freeswan-2.04-x509-1.5.3
+
+Revision 1.25  2003/04/02 20:28:33  mcr
+	document for NETJIGVERBOSE environment variable.
+
+Revision 1.24  2003/04/02 02:17:52  mcr
+	added documentation on "PACKETRATE"
+
+Revision 1.23  2003/02/27 09:28:24  mcr
+	added documentation for *_RUN2_SCRIPT.
+
+Revision 1.22  2003/02/20 20:00:44  mcr
+	added documentation for ${host}HOST.
+
+Revision 1.21  2003/02/20 19:56:11  mcr
+	documented new umlXhost test case.
+
+Revision 1.20  2002/12/06 02:11:42  mcr
+	added new test type, module_compile.
+
+Revision 1.19  2002/12/04 03:47:06  mcr
+	added documentation of various *TESTDEBUG options in
+	the testing environment.
+
+Revision 1.18  2002/10/31 19:01:31  mcr
+	documentation for RUN_*_SCRIPT.
+
+Revision 1.17  2002/09/11 19:43:36  mcr
+	added documentation on format of TESTLIST.
+
+Revision 1.16  2002/09/11 19:26:48  mcr
+	renamed umlpluto -> umlplutotest.
+
+Revision 1.15  2002/07/29 22:27:12  mcr
+	added kernel_patch_test test type.
+
+Revision 1.14  2002/06/19 18:24:44  mcr
+	renamed SCRIPT to INIT_SCRIPT.
+
+Revision 1.13  2002/06/19 10:06:07  mcr
+	added nightly.html to the documentation tree.
+
+Revision 1.12  2002/06/19 09:19:26  mcr
+	wrote documentation for umlpluto parts of makecheck,
+	and adjusted scripts for consistency.
+
+Revision 1.11  2002/06/19 07:26:31  mcr
+	added FINAL_SCRIPT to be run after sending packets through.
+	renamed "SCRIPT" to "INIT_SCRIPT" (left compat variable)
+
+Revision 1.10  2002/06/17 05:40:57  mcr
+	Added test cases for the "make rpm" machinery.
+
+Revision 1.9  2002/06/08 17:12:49  mcr
+	added new libtest test type for use in testing libfreeswan
+
+Revision 1.8  2002/05/27 00:19:38  mcr
+	removed reference to single_netjig.png because mkhtml does not
+	grok it.
+
+Revision 1.7  2002/05/07 01:31:52  mcr
+	documented the new "mkinsttest" target type.
+
+Revision 1.6  2002/05/05 23:10:50  mcr
+	added documentation of $TEST_TYPE variable.
+
+Revision 1.5  2002/04/19 22:48:41  mcr
+	added documentation on NETJIGDEBUG and CONSOLEDIFFDEBUG.
+
+Revision 1.4  2002/04/01 23:59:46  mcr
+	added documentation on REF_{PUB,PRIV}_FILTER.
+
+Revision 1.3  2002/04/01 23:38:46  mcr
+	redo of updates to makecheck
+
+Revision 1.2  2002/03/12 21:12:07  mcr
+	initial stab at documentation on klips testing infrastructure.
+
+
+-->
+</head>
+
+<body>
+
+<h1><a name="makecheck">How to configure to use "make check"</a></h1>
+
+<H2>What is "make check"</H2>
+<p>
+"make check" is a target in the top level makefile. It takes care of
+running a number of unit and system tests to confirm that FreeSWAN has 
+been compiled correctly, and that no new bugs have been introduced.
+</p>
+<p>
+As FreeSWAN contains both kernel and userspace components, doing testing
+of FreeSWAN requires that the kernel be simulated. This is typically difficult
+to do as a kernel requires that it be run on bare hardware. A technology
+has emerged that makes this simpler. This is
+<A HREF="http://user-mode-linux.sourceforge.net">User Mode Linux</A>. 
+</p>
+
+<p>
+User-Mode Linux is a way to build a Linux kernel such that it can run as a process
+under another Linux (or in the future other) kernel. Presently, this can only be
+done for 2.4 guest kernels. The host kernel can be 2.2 or 2.4. 
+</p>
+
+<p>
+"make check" expects to be able to build User-Mode Linux kernels with FreeSWAN included. 
+To do this it needs to have some files downloaded and extracted prior
+to running "make check". This is described in the
+<A HREF="umltesting.html">UML testing</A> document.  
+</p>
+
+<p>
+After having run the example in the UML testing document and
+successfully brought up the four machine combination, you are ready to 
+use "make check"
+</p>
+
+<h2>Running "make check"</h2>
+<p>
+"make check" works by walking the FreeSWAN source tree invoking the
+"check" target at each node. At present there are tests defined only
+for the <CODE>klips</CODE> directory. These tests will use the UML
+infrastructure to test out pieces of the <CODE>klips</CODE> code.
+</p>
+<p>
+The results of the tests can be recorded. If the environment variable
+<CODE>$REGRESSRESULTS</CODE> is non-null, then the results of each
+test will be recorded. This can be used as part of a nightly
+regression testing system, see
+<A HREF="nightly.html">Nightly testing</A> for more details.
+</p>
+<p>
+"make check" otherwise prints a minimal amount of output for each
+test, and indicates pass/fail status of each test as they are run.
+Failed tests do not cause failure of the target in the form of exit
+codes. 
+</p>
+
+<H1>How to write a "make check" test</H1>
+
+<h2>Structure of a test</h2>
+
+<p>
+Each test consists of a set of directories under <CODE>testing/</CODE>.
+There are directories for <CODE>klips</CODE>, <CODE>pluto</CODE>, <CODE>packaging</CODE>
+and <CODE>libraries</CODE>.
+Each directory has a list of tests to run is stored in a file called <CODE>TESTLIST</CODE> in that directory. e.g. <CODE>testing/klips/TESTLIST</CODE>.
+</P>
+
+<H2 NAME="TESTLIST">The TESTLIST</H2>
+<P>
+This isn't actually a shell script. It just looks like one. Some tools other than
+/bin/sh process it. Lines that start with # are comments. </P>
+
+<PRE>
+# test-kind     directory-containing-test       expectation     [PR#]
+</PRE>
+
+<P>The first word provides the test type, detailed below. </P>
+<P> The second word is the name of the test to run. This the directory
+in which the test case is to be found..</P>
+<P>The third word may be one of: 
+<DL>
+<DT> blank/good</DT>
+<DD>the test is believed to function, report failure</DD>
+<DT> bad</DT>
+<DD> the test is known to fail, report unexpected success</DD>
+<DT> suspended</DT>
+<DD> the test should not be run</DD>
+</DL>
+
+<P>
+The fourth word may be a number, which is a PR# if the test is
+failing.
+</P>
+
+<H2>Test kinds</H2>
+The test types are:
+
+<DL>
+<DT>skiptest</DT>
+<DD>means run no test.</DD>
+<DT>ctltest</DT>
+<DD>means run a single system without input/output.</DD>
+<DT>klipstest</DT>
+<DD>means run a single system with input/output networks</DD>
+<DT><A HREF="#umlplutotest">umlplutotest</A></DT>
+<DD>means run a pair of systems</DD>
+<DT><A HREF="#umlXhost">umlXhost</A></DT>
+<DD>run an arbitrary number of systems</DT>
+<DT>suntest (TBD)</DT>
+<DD>means run a quad of east/west/sunrise/sunset</DD>
+<DT>roadtest (TBD)</DT>
+<DD>means run a trio of east-sunrise + warrior</DD>
+<DT>extrudedtest (TBD)</DT>
+<DD>means run a quad of east-sunrise + warriorsouth + park</DD>
+<DT>mkinsttest</TD>
+<DD>a test of the "make install" machinery.</DD>
+<DT>kernel_test_patch</TD>
+<DD>a test of the "make kernelpatch" machinery.</DD>
+</DL>
+
+Tests marked (TBD) have yet to be fully defined.
+</p>
+
+<p>
+Each test directory has a file in it called <CODE>testparams.sh</CODE>.
+This file sets a number of environment variables to define the
+parameters of the test.
+</p>
+
+<H2>Common parameters</H2>
+<DL>
+<DT>TESTNAME</DT>
+<DD>the name of the test (repeated for checking purposes)</DD>
+
+<DT>TEST_TYPE</DT>
+<DD>the type of the test (repeat of type type above)</DD>
+
+<DT>TESTHOST</DT>
+<DD>the name of the UML machine to run for the test, typically "east"
+  or "west"</DD>
+
+<DT>TEST_PURPOSE</DT>
+<DD>The purpose of the test is one of: 
+
+<DL>
+<DT>goal</DT>
+<DD>The goal purpose is where a test is defined for code that is not yet
+finished. The test indicates when the goals have in fact been reached.</DD>
+<DT>regress</DT>
+<DD>This is a test to determine that a previously existing bug has been repaired. This 
+test will initially be created to reproduce the bug in isolation, and then the bug will 
+be fixed.</DD> 
+<DT>exploit</DT>
+<DD>This is a set of packets/programs that causes a vulnerability to be
+exposed. It is a specific variation of the regress option.</DD>
+</DL>
+</DD>
+
+<DT>TEST_GOAL_ITEM<DT>
+<DD>in the case of a goal test, this is a reference to the requirements document</DD>
+
+<DT>TEST_PROB_REPORT</DT>
+<DD>in the case of regression test, this the problem report number from GNATS</DD>
+
+<DT>TEST_EXPLOIT_URL</DT>
+<DD>in the case of an exploit, this is a URL referencing the paper explaining 
+the origin of the test and the origin of exploit software</DD>
+
+<DT>REF_CONSOLE_OUTPUT</DT>
+<DD>a file in the test directory that contains the sanitized console
+  output against which to compare the output of the actual test.</DD>
+<DT>REF_CONSOLE_FIXUPS</DT>
+<DD>a list of scripts (found in <CODE>klips/test/fixups</CODE>) to
+  apply to sanitize the console output of the machine under test.
+  These are typically perl, awk or sed scripts that remove things in
+  the kernel output that change each time the test is run and/or
+  compiled.
+</DD>
+<DT>INIT_SCRIPT</DT>
+<DD><p>a file of commands that is fed into the virtual machine's console
+  in single user mode prior to starting the tests. This file will
+  usually set up any eroute's and SADB entries that are required for
+  the test. </p>
+<p>Lines beginning with # are skipped. Blank lines are
+  skipped. Otherwise, a shell prompted is waited for each time
+  (consisting of <CODE>\n#</CODE>) and then the command is sent.
+  Note that the prompt is waited for before the command and not after, 
+  so completion of the last command in the script is not
+  required. This is often used to invoke a program to monitor the
+  system, e.g. <CODE>ipsec pf_key</CODE>.
+</P>
+<DT>RUN_SCRIPT</DT>
+<DD><P>a file of commands that is fed into the virtual machine's console
+      in single user mode, before the packets are sent. On single machine
+      tests, this script doesn't provide any more power than INIT_SCRIPT,
+      but is implemented for consistency's sake.</P>
+<DT>FINAL_SCRIPT</DT>
+<DD><p>a file of commands that is fed into the virtual machine's console
+  in single user mode after the final packet is sent. Similar to INIT_SCRIPT,
+  above. If not specified, then the single command "halt" is sent.
+  If specified, then the script should end with a halt command to
+  nicely shutdown the UML.
+</P>
+<DT>CONSOLEDIFFDEBUG</DT>
+<DD>If set to "true" then the series of console fixups (see REF_CONSOLE_FIXUPS) will be output after it is constructed. (It should be set to "false", or unset otherwise)</DD>
+<DT>NETJIGDEBUG</DT>
+<DD>If set to "true" then the series of console fixups (see REF_CONSOLE_FIXUPS) will be output after it is constructed. (It should be set to "false", or unset otherwise)</DD>
+<DT>NETJIGTESTDEBUG</DT>
+<DD> If set to "netjig", then the results of talking to the <CODE>uml_netjig</CODE>
+will be printed to stderr during the test. In addition, the jig will
+be invoked with --debug, which causes it to log its process ID, and
+wait 60 seconds before continuing. This can be used if you are trying
+to debug the <CODE>uml_netjig</CODE> program itself.</DT>
+<DT>HOSTTESTDEBUG</DT>
+<DD> If set to "hosttest", then the results of taling to the consoles of the UMLs will
+be printed to stderr during the test.</DT>
+<DT>NETJIGWAITUSER</DT>
+<DD> If set to "waituser", then the scripts will wait forever for user
+  input before they shut the tests down. Use this is if you are
+  debugging through the kernel.</DD>
+
+<DT>PACKETRATE</DT>
+<DD> A number, in miliseconds (default is 500ms) at which packets will
+  be replayed by the netjig.</DD>
+</DL>
+
+
+<H2>KLIPStest paramaters</H2>
+<P>
+The klipstest function starts a program
+(<CODE>testing/utils/uml_netjig/uml_netjig</CODE>) to
+setup a bunch of I/O sockets (that simulate network interfaces). It
+then exports the references to these sockets to the environment and
+invokes (using system()) a given script. It waits for the script to
+finish.
+</P>
+
+<!-- <IMG SRC="single_netjig.png" ALT="block diagram of uml_netjig"> -->
+
+<P>
+The script invoked (<CODE>testing/utils/host-test.tcl</CODE>) is a TCL
+<A HREF="http://expect.nist.gov/">expect</A> script that arranges to start the UML 
+and configure it appropriately for the test. The configuration is done 
+with the script given above for <VAR>INIT_SCRIPT</VAR>. The TCL script then forks,
+leaves the UML in the background and exits. uml_netjig continues. It then
+starts listening to the simulated network answering ARPs and inserting
+packets as appropriate.
+</P>
+
+<P>
+The klipstest function invokes <CODE>uml_netjig</CODE> with arguments
+to capture output from network interface(s) and insert packets as
+appropriate:
+<DL>
+<DT>PUB_INPUT</DT>
+<DD>a <A HREF="http://www.tcpdump.org/">pcap</A> file to feed in on
+  the public (encrypted) interface. (typically, eth1)</DD>
+<DT>PRIV_INPUT</DT>
+<DD>a pcap file to feed in on the private (plain-text) interface
+  (typically, eth0).</DD>
+<DT>REF_PUB_OUTPUT</DT>
+<DD>a text file containing tcpdump output. Packets on the public
+  (eth1) interface are captured to a
+  <A HREF="http://www.tcpdump.org/">pcap</A> file by
+  <CODE>uml_netjig</CODE>. The klipstest function then uses tcpdump on 
+  the file to produce text output, which is compared to the file given.</DD>
+<DT>REF_PUB_FILTER</DT>
+<DD>a program that will filter the TCPDUMP output to do further processing. Defaults to "cat".</DD>
+<DT>REF_PRIV_OUTPUT</DT>
+<DD>a text file containing tcpdump output. Packets on the private
+  (eth0) interface are captured and compared after conversion by
+  tcpdump, as with <VAR>REFPUBOUTPUT</VAR>.</DD>
+<DT>REF_PRIV_FILTER</DT>
+<DD>a program that will filter the TCPDUMP output to do further processing. Defaults to "cat".</DD>
+<DT>EXITONEMPTY</DT>
+<DD>a flag for <CODE>uml_netjig</CODE>. It should contain
+  "--exitonempty" of uml_netjig should exit when all of the input
+  (<VAR>PUBINPUT</VAR>,<VAR>PRIVINPUT</VAR>) packets have been injected.</DD>
+<DT>ARPREPLY</DT>
+<DD>a flag for <CODE>uml_netjig</CODE>. It should contain "--arpreply" 
+  if <CODE>uml_netjig</CODE> should reply to ARP requests. One will
+  typically set this to avoid having to fudge the ARP cache manually.</DD>
+<DT>TCPDUMPFLAGS</DT>
+<DD>a set of flags for the tcpdump used when converting captured
+  output. Typical values will include "-n" to turn off DNS, and often
+  "-E" to set the decryption key (tcpdump 3.7.1 and higher only) for
+  ESP packets. The "-t" flag (turn off timestamps) is provided automatically</DD>
+
+<DT>NETJIG_EXTRA</DT>
+<DD>additional comments to be sent to the netjig. This may arrange to
+  record or create additional networks, or may toggle options.
+</DL>
+
+<H2>mkinsttest paramaters</H2>
+<P>
+The basic concept of the <CODE>mkinsttest</CODE> test type is that it 
+performs a "make install" to a temporary $DESTDIR. The resulting tree can then
+be examined to determine if it was done properly. The files can be uninstalled
+to determine if the file list was correct, or the contents of files can be
+examined more precisely.
+</P>
+
+<DL>
+<DT>INSTALL_FLAGS</DT>
+<DD>If set, then an install will be done. This provides the set of flags to 
+provide for the install. The target to be used (usually "install") must be 
+among the flags. </DD>  
+<DT>POSTINSTALL_SCRIPT</DT>
+<DD>If set, a script to run after initial "make install". Two arguments are provided: an absolute path to the root of the FreeSWAN src tree, and an absolute path to the temporary installation area.</DD>
+<DT>INSTALL2_FLAGS</DT>
+<DD>If set, a second install will be done using these flags. Similarly to
+INSTALL_FLAGS, the target must be among the flags. </DD>
+<DT>UNINSTALL_FLAGS</DT>
+<DD>If set, an uninstall will be done using these flags. Similarly to
+INSTALL_FLAGS, the target (usually "uninstall") must be among the flags.</DD> 
+<DT>REF_FIND_f_l_OUTPUT</DT>
+<DD>If set, a <CODE>find $ROOT ( -type f -or -type -l )</CODE> will be done to get a list of a real files and symlinks. The resulting file will be compared
+to the file listed by this option.</DD>
+<DT>REF_FILE_CONTENTS</DT>
+<DD>If set, it should point to a file containing records for the form:
+<PRE>
+  <VARIABLE>reffile</VARIABLE>   <VARIABLE>samplefile</VARIABLE>
+</PRE>
+one record per line. A diff between the provided reference file, and the
+sample file (located in the temporary installation root) will be done for
+each record.
+</DD>
+</DL>
+
+<H2>rpm_build_install_test paramaters</H2>
+<P>
+The <CODE>rpm_build_install_test</CODE> type is to verify that the proper
+packing list is produced by "make rpm", and that the mechanisms for
+building the kernel modules produce consistent results.
+</P>
+
+<DL>
+<DT>RPM_KERNEL_SOURCE</DT>
+<DD>Point to an extracted copy of the RedHat kernel source code. Variables
+from the environment may be used.</DD>  
+<DT>REF_RPM_CONTENTS</DT>
+<DD>This is a file containing one record per line. Each record consists
+of a RPM name (may contain wildcards) and a filename to compare the
+contents to. The RPM will be located and a file list will be produced with
+rpm2cpio.</DD>
+</DL>
+
+<H2>libtest paramaters</H2>
+<P>
+The libtest test is for testing library routines. The library file is
+expected to provided an <CODE>#ifdef</CODE> by the name of
+<VAR>library</VAR><CODE_MAIN</CODE>. 
+The libtest type invokes the C compiler to compile this file, links it against
+<CODE>libfreeswan.a</CODE> (to resolve any other dependancies) and runs the
+test with the <CODE>-r</CODE> argument to invoke a regression test.</P>
+<P>The library test case is expected to do a self-test, exiting with status code 0 if everything is okay, and with non-zero otherwise. A core dump (exit code greater than 128) is noted specifically.
+</P>
+<P>
+Unlike other tests, there are no subdirectories required, or other
+parameters to set.  
+</P>
+
+<H2 NAME="umlplutotest">umlplutotest paramaters</H2>
+<P>
+The umlplutotest function starts a pair of user mode line processes.
+This is a 2-host version of umlXhost. The "EAST" and "WEST" slots are defined.
+</P>
+
+<H2 NAME="umlXhost">umlXhost parameters</H2>
+<P>
+The umlXtest function starts an arbitrary number of user mode line processes.
+</P>
+
+<!-- <IMG SRC="single_netjig.png" ALT="block diagram of uml_netjig"> -->
+
+<P>
+The script invoked (<CODE>testing/utils/Xhost-test.tcl</CODE>) is a TCL
+<A HREF="http://expect.nist.gov/">expect</A> script that arranges to start each
+UML   
+and configure it appropriately for the test. It then starts listening
+(using uml_netjig) to the simulated network answering ARPs and
+inserting packets as appropriate.  
+</P>
+
+<P>
+umlXtest has a series of slots, each of which should be filled by a host.
+The list of slots is controlled by the variable, XHOST_LIST. This variable
+should be set to a space seperated list of slots. The former umlplutotest
+is now implemented as a variation of the umlXhost test,
+with XHOST_LIST="EAST WEST".
+</P>
+
+<P>
+For each host slot that is defined, a series of variables should be
+filled in, defining what configuration scripts to use for that host.
+</P>
+
+<P>
+The following are used to control the console input and output to the system.
+Where the string ${host} is present, the host slot should be filled in.
+I.e. for the two host system with XHOST_LIST="EAST WEST", then the
+variables: EAST_INIT_SCRIPT and WEST_INIT_SCRIPT will exist.
+<DL>
+<DT>${host}HOST</DT>
+<DD>The name of the UML host which will fill this slot</DD>
+<DT>${host}_INIT_SCRIPT</DT>
+<DD><p>a file of commands that is fed into the virtual machine's console
+  in single user mode prior to starting the tests. This file will
+  usually set up any eroute's and SADB entries that are required for
+  the test. Similar to INIT_SCRIPT, above.</p>
+<DT>${host}_RUN_SCRIPT</DT>
+<DD><P>a file of commands that is fed into the virtual machine's console
+      in single user mode, before the packets are sent. This set of 
+      commands is run after all of the virtual machines are initialized.
+      I.e. after EAST_INIT_SCRIPT <B>AND</B> WEST_INIT_SCRIPT. This script
+      can therefore do things that require that all machines are properly
+      configured.</P>
+<DT>${host}_RUN2_SCRIPT</DT>
+<DD><P>a file of commands that is fed into the virtual machine's console
+      in single user mode, after the packets are sent. This set of 
+      commands is run before any of the virtual machines have been shut
+      down. (I.e. before EAST_FINAL_SCRIPT <B>AND</B> WEST_FINAL_SCRIPT.)
+      This script can therefore catch post-activity status reports.</P>
+<DT>${host}_FINAL_SCRIPT</DT>
+<DD><p>a file of commands that is fed into the virtual machine's console
+  in single user mode after the final packet is sent. Similar to INIT_SCRIPT,
+  above. If not specified, then the single command "halt" is sent. Note that
+  when this script is run, the other virtual machines may already have been killed.
+  If specified, then the script should end with a halt command to nicely
+  shutdown the UML. 
+</P>
+<DT>REF_${host}_CONSOLE_OUTPUT</DT>
+<DD>Similar to REF_CONSOLE_OUTPUT, above.</DT>
+</DL>
+</P>
+
+<P>Some additional flags apply to all hosts:
+<DL>
+<DT>REF_CONSOLE_FIXUPS</DT>
+<DD>a list of scripts (found in <CODE>klips/test/fixups</CODE>) to
+  apply to sanitize the console output of the machine under test.
+  These are typically perl, awk or sed scripts that remove things in
+  the kernel output that change each time the test is run and/or
+  compiled.
+</DD>
+</DL>
+</P>
+
+<P> In addition to input to the console, the networks may have input
+fed to them:
+<DL>
+<DT>EAST_INPUT/WEST_INPUT</DT>
+<DD>a <A HREF="http://www.tcpdump.org/">pcap</A> file to feed in on
+  the private network side of each network. The "EAST" and "WEST" here 
+refer to the networks, not the hosts.</DD>
+<DT>REF_PUB_FILTER</DT>
+<DD>a program that will filter the TCPDUMP output to do further processing. Defaults to "cat".</DD>
+<DT>REF_EAST_FILTER/REF_WEST_FILTER</DT>
+<DD>a program that will filter the TCPDUMP output to do further processing. Defaults to "cat".</DD><
+<DT>TCPDUMPFLAGS</DT>
+<DD>a set of flags for the tcpdump used when converting captured
+  output. Typical values will include "-n" to turn off DNS, and often
+  "-E" to set the decryption key (tcpdump 3.7.1 and higher only) for
+  ESP packets. The "-t" flag (turn off timestamps) is provided automatically</DD>
+<DT>REF_EAST_OUTPUT/REF_WEST_OUTPUT</DT>
+<DD>a text file containing tcpdump output. Packets on the private
+  (eth0) interface are captured and compared after conversion by
+  tcpdump, as with <VAR>REF_PUB_OUTPUT</VAR>.</DD>
+</P>
+
+<P>
+There are two additional environment variables that may be set on the
+command line:
+<DL>
+<DT> NETJIGVERBOSE=verbose export NETJIGVERBOSE</DT>
+<DD> If set, then the test output will be "chatty", and let you know what
+  commands it is running, and as packets are sent. Without it set, the
+  output is limited to success/failure messages.</DD>
+<DT> NETJIGTESTDEBUG=netjig export NETJIGTESTDEBUG</DT>
+<DD> This will enable debugging of the communication with uml_netjig,
+  and turn on debugging in this utility.
+  This does not imply NETJIGVERBOSE.</DL>
+<DT> HOSTTESTDEBUG=hosttest export HOSTTESTDEBUG</DT>
+<DD> This will show all interactions with the user-mode-linux
+  consoles</DD>
+</DL>
+</P>
+
+<H2 NAME="kernelpatch">kernel_patch_test paramaters</H2>
+<P>
+The kernel_patch_test function takes some kernel source, copies it with
+lndir, and then applies the patch as produced by "make kernelpatch".
+</P>
+<P>
+The following are used to control the input and output to the system:
+<DL>
+<DT>KERNEL_NAME</DT>
+<DD>the kernel name, typically something like "linus" or "rh"</DD>
+<DT>KERNEL_VERSION</DT>
+<DD>the kernel version number, as in "2.2" or "2.4".</DD>
+<DT>KERNEL_${KERNEL_NAME}${KERNEL_VERSION}_SRC</DT>
+<DD>This variable should set in the environment, probably in
+  ~/freeswan-regress-env.sh. Examples of this variables would be
+  KERNEL_LINUS2_0_SRC or KERNEL_RH7_3_SRC. This variable should point
+  to an extracted copy of the kernel source in question.</DD>
+<DT>REF_PATCH_OUTPUT</DT>
+<DD>a copy of the patch output to compare against</DD>
+<DT>KERNEL_PATCH_LEAVE_SOURCE</DT>
+<DD>If set to a non-empty string, then the patched kernel source is not
+  removed at the end of the test. This will typically be set in the
+  environment while debugging.</DD>
+</DL>
+</P>
+
+<H2 NAME="modtest">module_compile paramaters</H2>
+<P>
+The module_compile test attempts to build the KLIPS module against a
+given set of kernel source. This is also done by the RPM tests, but
+in a very specific manner.
+</P>
+<P>
+There are two variations of this test - one where the kernel either
+doesn't need to be configured, or is already done, and tests were there
+is a local configuration file.
+</P>
+<P>
+Where the kernel doesn't need to be configured, the kernel source that
+is found is simply used. It may be a RedHat-style kernel, where one
+can cause it to configure itself via rhconfig.h-style definitions. Or,
+it may just be a kernel tree that has been configured. 
+</P>
+<P>
+If the variable KERNEL_CONFIG_FILE is set, then a new directory is
+created for the kernel source. It is populated with lndir(1). The referenced
+file is then copied in as .config, and "make oldconfig" is used to configure
+the kernel. This resulting kernel is then used as the reference source.
+</P>
+<p>
+In all cases, the kernel source is found the same was for the kernelpatch
+test, i.e. via KERNEL_VERSION/KERNEL_NAME and KERNEL_${KERNEL_NAME}${KERNEL_VERSION}_SRC.</P>
+<P>
+Once there is kernel source, the module is compiled using the top-level
+"make module" target. 
+</P>
+<P>
+The test is considered successful if an executable is found in OUTPUT/module/ipsec.o at the end of the test.
+</P>
+<DL>
+<DT>KERNEL_NAME</DT>
+<DD>the kernel name, typically something like "linus" or "rh"</DD>
+<DT>KERNEL_VERSION</DT>
+<DD>the kernel version number, as in "2.2" or "2.4".</DD>
+<DT>KERNEL_${KERNEL_NAME}${KERNEL_VERSION}_SRC</DT>
+<DD>This variable should set in the environment, probably in
+  ~/freeswan-regress-env.sh. Examples of this variables would be
+  KERNEL_LINUS2_0_SRC or KERNEL_RH7_3_SRC. This variable should point
+  to an extracted copy of the kernel source in question.</DD>
+<DT>KERNEL_CONFIG_FILE</DT>
+<DD>The configuration file for the kernel.</DD>
+<DT>KERNEL_PATCH_LEAVE_SOURCE</DT>
+<DD>If set to a non-empty string, then the configured kernel source is not
+  removed at the end of the test. This will typically be set in the
+  environment while debugging.</DD>
+<DT>MODULE_DEF_INCLUDE</DT>
+<DD>The include file that will be used to configure the KLIPS module, and
+  possibly the kernel source. </DD>
+</DL>
+
+<H1>Current pitfalls</H1>
+
+<DL>
+<DT> "tcpdump dissector" not available. </DT>
+<DD> This is a non-fatal warning. If uml_netjig is invoked with the -t 
+  option, then it will attempt to use tcpdump's dissector to decode
+  each packet that it processes. The dissector is presently not
+  available, so this option it normally turned off at compile time.
+  The dissector library will be released with tcpdump version
+  4.0.</DD>
+</DL>
+
+</body>
+</html>
\ No newline at end of file
diff --git a/doc/src/manpages.html b/doc/src/manpages.html
new file mode 100644
index 000000000..27a9aa7b3
--- /dev/null
+++ b/doc/src/manpages.html
@@ -0,0 +1,155 @@
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>FreeS/WAN man pages</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, FreeSWAN, manpage, manual, page">
+  <!--
+
+  Written by Sandy Harris for the Linux FreeS/WAN project
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: manpages.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+
+<body>
+<h1><a name="manpages">FreeS/WAN manual pages</a></h1>
+
+<p>The various components of Linux FreeS/WAN are of course documented in
+standard Unix manual pages, accessible via the man(1) command.</p>
+
+<p>Links here take you to an HTML version of the man pages.</p>
+
+<h2><a name="man.file">Files</a></h2>
+<dl>
+  <dt><a href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a></dt>
+    <dd>IPsec configuration and connections</dd>
+  <dt><a href="manpage.d/ipsec.secrets.5.html">ipsec.secrets(5)</a></dt>
+    <dd>secrets for IKE authentication, either pre-shared keys or RSA private
+      keys</dd>
+</dl>
+
+<p>These files are also discussed in the <a
+href="config.html">configuration</a> section.</p>
+
+<h2><a name="man.command">Commands</a></h2>
+
+<p>Many users will never give most of the FreeS/WAN commands directly.
+Configure the files listed above correctly and everything should be
+automatic.</p>
+
+<p>The exceptions are commands for mainpulating the <a
+href="glossary.html#RSA">RSA</a> keys used in Pluto authentication:</p>
+<dl>
+  <dt><a href="manpage.d/ipsec_rsasigkey.8.html">ipsec_rsasigkey(8)</a></dt>
+    <dd>generate keys</dd>
+  <dt><a href="manpage.d/ipsec_newhostkey.8.html">ipsec_newhostkey(8)</a></dt>
+    <dd>generate keys in a convenient format</dd>
+  <dt><a
+  href="manpage.d/ipsec_showhostkey.8.html">ipsec_showhostkey(8)</a></dt>
+    <dd>extract <a href="glossary.html#RSA">RSA</a> keys from <a
+      href="manpage.d/ipsec.secrets.5.html">ipsec.secrets(5)</a> (or
+      optionally, another file) and format them for insertion in <a
+      href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a> or in DNS
+    records</dd>
+</dl>
+
+<p>Note that:</p>
+<ul>
+  <li>These keys are for <strong>authentication only</strong>. They are
+    <strong>not secure for encryption</strong>.</li>
+  <li>The utility uses random(4) as a source of <a
+    href="glossary.html#random">random numbers</a>. This may block for some
+    time if there is not enough activity on the machine to provide the
+    required entropy. You may want to give it some bogus activity such as
+    random mouse movements or some command such as <nobr><tt>du /usr &gt; /dev/null
+    &amp;</tt></nobr>.</li>
+</ul>
+
+<p>The following commands are fairly likely to be used, if only for testing
+and status checks:</p>
+<dl>
+  <dt><a href="manpage.d/ipsec.8.html">ipsec(8)</a></dt>
+    <dd>invoke IPsec utilities</dd>
+  <dt><a href="manpage.d/ipsec_setup.8.html">ipsec_setup(8)</a></dt>
+    <dd>control IPsec subsystem</dd>
+  <dt><a href="manpage.d/ipsec_auto.8.html">ipsec_auto(8)</a></dt>
+    <dd>control automatically-keyed IPsec connections</dd>
+  <dt><a href="manpage.d/ipsec_manual.8.html">ipsec_manual(8)</a></dt>
+    <dd>take manually-keyed IPsec connections up and down</dd>
+  <dt><a href="manpage.d/ipsec_ranbits.8.html">ipsec_ranbits(8)</a></dt>
+    <dd>generate random bits in ASCII form</dd>
+  <dt><a href="manpage.d/ipsec_look.8.html">ipsec_look(8)</a></dt>
+    <dd>show minimal debugging information</dd>
+  <dt><a href="manpage.d/ipsec_barf.8.html">ipsec_barf(8)</a></dt>
+    <dd>spew out collected IPsec debugging information</dd>
+</dl>
+
+<p>The lower-level utilities listed below are normally invoked via scripts
+listed above, but they can also be used directly when required.</p>
+<dl>
+  <dt><a href="manpage.d/ipsec_eroute.8.html">ipsec_eroute(8)</a></dt>
+    <dd>manipulate IPsec extended routing tables</dd>
+  <dt><a href="manpage.d/ipsec_klipsdebug.8.html">ipsec_klipsdebug(8)</a></dt>
+    <dd>set Klips (kernel IPsec support) debug features and level</dd>
+  <dt><a href="manpage.d/ipsec_pluto.8.html">ipsec_pluto(8)</a></dt>
+    <dd>IPsec IKE keying daemon</dd>
+  <dt><a href="manpage.d/ipsec_spi.8.html">ipsec_spi(8)</a></dt>
+    <dd>manage IPsec Security Associations</dd>
+  <dt><a href="manpage.d/ipsec_spigrp.8.html">ipsec_spigrp(8)</a></dt>
+    <dd>group/ungroup IPsec Security Associations</dd>
+  <dt><a href="manpage.d/ipsec_tncfg.8.html">ipsec_tncfg(8)</a></dt>
+    <dd>associate IPsec virtual interface with real interface</dd>
+  <dt><a href="manpage.d/ipsec_whack.8.html">ipsec_whack(8)</a></dt>
+    <dd>control interface for IPsec keying daemon</dd>
+</dl>
+
+<h2><a name="man.lib">Library routines</a></h2>
+<dl>
+  <dt><a href="manpage.d/ipsec_atoaddr.3.html">ipsec_atoaddr(3)</a></dt>
+  <dt><a href="manpage.d/ipsec_addrtoa.3.html">ipsec_addrtoa(3)</a></dt>
+    <dd>convert Internet addresses to and from ASCII</dd>
+  <dt><a href="manpage.d/ipsec_atosubnet.3.html">ipsec_atosubnet(3)</a></dt>
+  <dt><a href="manpage.d/ipsec_subnettoa.3.html">ipsec_subnettoa(3)</a></dt>
+    <dd>convert subnet/mask ASCII form to and from addresses</dd>
+  <dt><a href="manpage.d/ipsec_atoasr.3.html">ipsec_atoasr(3)</a></dt>
+    <dd>convert ASCII to Internet address, subnet, or range</dd>
+  <dt><a href="manpage.d/ipsec_rangetoa.3.html">ipsec_rangetoa(3)</a></dt>
+    <dd>convert Internet address range to ASCII</dd>
+  <dt>ipsec_atodata(3)</dt>
+  <dt><a href="manpage.d/ipsec_datatoa.3.html">ipsec_datatoa(3)</a></dt>
+    <dd>convert binary data from and to ASCII formats</dd>
+  <dt><a href="manpage.d/ipsec_atosa.3.html">ipsec_atosa(3)</a></dt>
+  <dt><a href="manpage.d/ipsec_satoa.3.html">ipsec_satoa(3)</a></dt>
+    <dd>convert IPsec Security Association IDs to and from ASCII</dd>
+  <dt><a href="manpage.d/ipsec_atoul.3.html">ipsec_atoul(3)</a></dt>
+  <dt><a href="manpage.d/ipsec_ultoa.3.html">ipsec_ultoa(3)</a></dt>
+    <dd>convert unsigned-long numbers to and from ASCII</dd>
+  <dt><a href="manpage.d/ipsec_goodmask.3.html">ipsec_goodmask(3)</a></dt>
+    <dd>is this Internet subnet mask a valid one?</dd>
+  <dt><a href="manpage.d/ipsec_masktobits.3.html">ipsec_masktobits(3)</a></dt>
+    <dd>convert Internet subnet mask to bit count</dd>
+  <dt><a href="manpage.d/ipsec_bitstomask.3.html">ipsec_bitstomask(3)</a></dt>
+    <dd>convert bit count to Internet subnet mask</dd>
+  <dt><a
+  href="manpage.d/ipsec_optionsfrom.3.html">ipsec_optionsfrom(3)</a></dt>
+    <dd>read additional ``command-line'' options from file</dd>
+  <dt><a href="manpage.d/ipsec_subnetof.3.html">ipsec_subnetof(3)</a></dt>
+    <dd>given Internet address and subnet mask, return subnet number</dd>
+  <dt><a href="manpage.d/ipsec_hostof.3.html">ipsec_hostof(3)</a></dt>
+    <dd>given Internet address and subnet mask, return host part</dd>
+  <dt><a
+  href="manpage.d/ipsec_broadcastof.3.html">ipsec_broadcastof(3)</a></dt>
+    <dd>given Internet address and subnet mask, return broadcast address</dd>
+</dl>
+</body>
+</html>
diff --git a/doc/src/nightly.html b/doc/src/nightly.html
new file mode 100644
index 000000000..d86037884
--- /dev/null
+++ b/doc/src/nightly.html
@@ -0,0 +1,164 @@
+<html>
+<head>
+<title>FreeS/WAN nightly testing guide</title>
+<!-- Changed by: Michael Richardson, 23-Jul-2002 -->
+<meta name="keywords" content="Linux, IPsec, VPN, security, FreeSWAN, testing, User-Mode-Linux, UML">
+
+<!--
+
+Written by Michael Richardson for the Linux FreeS/WAN project
+Freely distributable under the GNU General Public License
+
+More information at www.freeswan.org
+Feedback to users@lists.freeswan.org
+
+$Id: nightly.html,v 1.1 2004/03/15 20:35:24 as Exp $
+
+$Log: nightly.html,v $
+Revision 1.1  2004/03/15 20:35:24  as
+added files from freeswan-2.04-x509-1.5.3
+
+Revision 1.3  2002/07/23 18:42:16  mcr
+	added instructions on setup of nightly build.
+
+Revision 1.2  2002/06/19 10:06:07  mcr
+	added nightly.html to the documentation tree.
+
+Revision 1.1  2002/05/24 03:33:30  mcr
+	start at document on nightly regression testing.
+
+
+-->
+</head>
+
+<body>
+
+<h1><a name="nightly">Nightly regression testing</a></h1>
+
+<p>
+The nightly regression testing system consists of several shell scripts
+and some perl scripts. The goal is to check out a fresh tree, run "make check" on it,
+record the results and summarize the results to the team and to the web site.
+</p>
+
+<P>
+Output can be found on <A HREF="http://bugs.freeswan.org:81/">adams</A>,
+although the tests are actually run on another project machine.</P>
+
+<H1><A name="nightlyhowto">How to setup the nightly build</A></h1>
+
+<P>
+The best way to do nightly testing is to setup a new account. We call the
+account "build" - you could call it something else, but there may
+still be some references to ~build in the scripts.
+</P>
+
+<H2> Files you need to know about </H2>
+<P>
+As few files as possible need to be extracted from the source tree -
+files are run from the source tree whenever possible. However, there
+are some bootstrap and configuration files that are necessary.
+</P>
+
+<P>
+There are 7 files in testing/utils that are involved:
+<DL>
+<DT> nightly-sample.sh </DT>
+<DD> This is the root of the build process. This file should be copied out
+of the CVS tree, to $HOME/bin/nightly.sh of the build account. This
+file should be invoked from cron. </DD>
+<DT> freeswan-regress-env-sample.sh </DT>
+<DD> This file should be copied to $HOME/freeswan-regress-env.sh. It
+  should be edited to localize the values. See below.</DD>
+<DT> regress-cleanup.pl </DT>
+<DD> This file needs to be copied to $HOME/bin/regress-cleanup.pl. It
+  is invoked by the nightly file before doing anything else. It
+  removes previous nights builds in order to free up disk space for
+  the build about to be done.</DD>
+<DT> teammail-sample.sh </DT>
+<DD> A script used to send results email to the "team". This sample
+  script could be copied to $HOME/bin/teammail.sh. This version will
+  PGP encrypt all the output to the team members. If this script is used,
+  then PGP will have to be properly setup to have the right keys.</DD>
+<DT> regress-nightly.sh </DT>
+<DD> This is the first stage of the nightly build. This stage will
+  call other scripts as appropriate, and will extract the source code
+  from CVS. This script should be copied to $HOME/bin/regress-nightly.sh</DD>
+<DT> regress-stage2.sh </DT>
+<DD> This is the second stage of the nightly build. It is called in
+  place. It essentially sets up the UML setup in umlsetup.sh, and
+  calls "make check".</DD>
+<DT> regress-summarize-results.pl
+<DD> This script will summarize the results from the tests to a
+  permanent directory set by $REGRESSRESULTS. It is invoked from the
+  stage2 nightly script.
+<DT> regress-chart.sh </DT>
+<DD> This script is called at the end of the build process, and will
+  summarize each night's results (as saved into $REGRESSRESULTS by
+  regress-summarize-results.pl) as a chart using gnuplot. Note that
+  this requires at least gnuplot 3.7.2.</DD>
+</DL>
+
+<H2>Configuring freeswan-regress-env.sh</H2>
+
+<P>For more info on KERNPOOL, UMLPATCH, BASICROOT and SHAREDIR, see
+  <A HREF="umltesting.html">User-Mode-Linux testing guide</A>.
+</P>
+
+<DL>
+<DT> KERNPOOL </DT>
+<DD> Extract copy of some kernel source to be used for UML builds</DD>
+<DT> UMLPATCH </DT>
+<DD> matching User-Mode-Linux patch.</DD>
+<DT> BASICROOT</DT>
+<DD> the root file system image (see
+  <A HREF="umltesting.html">User-Mode-Linux testing guide</A>).</DD>
+<DT> SHAREDIR=${BASICROOT}/usr/share</DT>
+<DD> The /usr/share to use.</DD>
+<DT> REGRESSTREE</DT>
+<DD> A directory in which to store the nightly regression
+  results. Directories will be created by date in this tree.</DD>
+
+<DT> TCPDUMP=tcpdump-3.7.1</DT>
+<DD> The path to the <A HREF="http://www.tcpdump.org/">tcpdump</A>
+  to use. This must have crypto compiled in, and must be at least 3.7.1</DT>
+
+<DT> KERNEL_RH7_2_SRC=/a3/kernel_sources/linux-2.4.9-13/</DT>
+<DD> An extracted copy of the RedHat 7.2. kernel source. If set, then
+  the packaging/rpm-rh72-install-01 test will be run, and an RPM will
+  be built as a test.</DD>
+  
+<DT> KERNEL_RH7_3_SRC=/a3/kernel_sources/rh/linux-2.4.18-5</DT>
+<DD> An extracted copy of the RedHat 7.3. kernel source. If set, then
+  the packaging/rpm-rh73-install-01 test will be run, and an RPM will
+  be built as a test.</DD>
+  
+<DT> NIGHTLY_WATCHERS="userid,userid,userid"</DT>
+<DD> The list of people who should receive nightly output. This is
+  used by teammail.sh</DD>
+
+<DT> FAILLINES=128</DT>
+<DD> How many lines of failed test output to include in the nightly
+  output</DD>
+
+<DT> PATH=$PATH:/sandel/bin export PATH</DT>
+<DD> You can also override the path if necessary here.</DD>
+
+<DT> CVSROOT=:pserver:anoncvs@ip212.xs4net.freeswan.org:/freeswan/MASTER</DT>
+<DD> The CVSROOT to use. This example may work for anonymous CVS, but
+  will be 12 hours behind the primary, and is still experimental</DD>
+
+<DT> SNAPSHOTSIGDIR=$HOME/snapshot-sig</DT>
+<DD> For the release tools, where to put the generated per-snapshot
+  signature keys</DD>
+
+<DT> LASTREL=1.97</DT>
+<DD> the name of the last release branch (to find the right
+  per-snapshot signature</DT>
+
+<DD>
+
+</DL>
+
+</body>
+</html>
\ No newline at end of file
diff --git a/doc/src/performance.html b/doc/src/performance.html
new file mode 100755
index 000000000..9d90acc62
--- /dev/null
+++ b/doc/src/performance.html
@@ -0,0 +1,576 @@
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>FreeS/WAN performance</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, FreeSWAN, performance, benchmark">
+  <!--
+
+  Written by Sandy Harris for the Linux FreeS/WAN project
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: performance.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+
+<body>
+<h1><a name="performance">Performance of FreeS/WAN</a></h1>
+The performance of FreeS/WAN is adequate for most applications.
+
+<p>In normal operation, the main concern is the overhead for encryption,
+decryption and authentication of the actual IPsec (<a
+href="glossary.html#ESP">ESP</a> and/or <a href="glossary.html#AH">AH</a>)
+data packets. Tunnel setup and rekeying occur so much less frequently than
+packet processing that, in general, their overheads are not worth worrying
+about.</p>
+
+<p>At startup, however, tunnel setup overheads may be significant. If you
+reboot a gateway and it needs to establish many tunnels, expect some delay.
+This and other issues for large gateways are discussed <a
+href="#biggate">below</a>.</p>
+
+<h2><a name="pub.bench">Published material</a></h2>
+
+<p>The University of Wales at Aberystwyth has done quite detailed speed tests
+and put <a href="http://tsc.llwybr.org.uk/public/reports/SWANTIME/">their
+results</a> on the web.</p>
+
+<p>Davide Cerri's <a href="http://www.linux.it/~davide/doc/">thesis (in
+Italian)</a> includes performance results for FreeS/WAN and for <a
+href="glossary.html#TLS">TLS</a>. He posted an <a
+href="http://lists.freeswan.org/pipermail/users/2001-December/006303.html">English
+summary</a> on the mailing list.</p>
+
+<p>Steve Bellovin used one of AT&amp;T Research's FreeS/WAN gateways as his
+data source for an analysis of the cache sizes required for key swapping in
+IPsec. Available as <a
+href="http://www.research.att.com/~smb/talks/key-agility.email.txt">text</a>
+or <a href="http://www.research.att.com/~smb/talks/key-agility.pdf">PDF
+slides</a> for a talk on the topic.</p>
+
+<p>See also the NAI work mentioned in the next section.</p>
+
+<h2><a name="perf.estimate">Estimating CPU overheads</a></h2>
+
+<p>We can come up with a formula that roughly relates CPU speed to the rate
+of IPsec processing possible. It is far from exact, but should be usable as a
+first approximation.</p>
+
+<p>An analysis of authentication overheads for high-speed networks, including
+some tests using FreeS/WAN, is on the <a
+href="http://www.pgp.com/research/nailabs/cryptographic/adaptive-cryptographic.asp">NAI
+Labs site</a>. In particular, see figure 3 in this <a
+href="http://download.nai.com/products/media/pgp/pdf/acsa_final_report.pdf">PDF
+document</a>. Their estimates of overheads, measured in Pentium II cycles per
+byte processed are:</p>
+
+<table border="1" align="center">
+  <tbody>
+    <tr>
+      <th></th>
+      <th>IPsec</th>
+      <th>authentication</th>
+      <th>encryption</th>
+      <th>cycles/byte</th>
+    </tr>
+    <tr>
+      <td>Linux IP stack alone</td>
+      <td>no</td>
+      <td>no</td>
+      <td>no</td>
+      <td align="right">5</td>
+    </tr>
+    <tr>
+      <td>IPsec without crypto</td>
+      <td>yes</td>
+      <td>no</td>
+      <td>no</td>
+      <td align="right">11</td>
+    </tr>
+    <tr>
+      <td>IPsec, authentication only</td>
+      <td>yes</td>
+      <td>SHA-1</td>
+      <td>no</td>
+      <td align="right">24</td>
+    </tr>
+    <tr>
+      <td>IPsec with encryption</td>
+      <td>yes</td>
+      <td>yes</td>
+      <td>yes</td>
+      <td align="right">not tested</td>
+    </tr>
+  </tbody>
+</table>
+
+<p>Overheads for IPsec with encryption were not tested in the NAI work, but
+Antoon Bosselaers' <a
+href="http://www.esat.kuleuven.ac.be/~bosselae/fast.html">web page</a> gives
+cost for his optimised Triple DES implementation as 928 Pentium cycles per
+block, or 116 per byte. Adding that to the 24 above, we get 140 cycles per
+byte for IPsec with encryption.</p>
+
+<p>At 140 cycles per byte, a 140 MHz machine can handle a megabyte -- 8
+megabits -- per second. Speeds for other machines will be proportional to
+this. To saturate a link  with capacity C megabits per second, you need a
+machine running at <var>C * 140/8 = C * 17.5</var> MHz.</p>
+
+<p>However, that estimate is not precise. It ignores the differences
+between:</p>
+<ul>
+  <li>NAI's test packets and real traffic</li>
+  <li>NAI's Pentium II cycles, Bosselaers' Pentium cycles, and your machine's
+    cycles</li>
+  <li>different 3DES implementations</li>
+  <li>SHA-1 and MD5</li>
+</ul>
+
+<p>and does not account for some overheads you will almost certainly have:</p>
+<ul>
+  <li>communication on the client-side interface</li>
+  <li>switching between multiple tunnels -- re-keying, cache reloading and so
+    on</li>
+</ul>
+
+<p>so we suggest using <var>C * 25</var> to get an estimate with a bit of a
+built-in safety factor.</p>
+
+<p>This covers only IP and IPsec processing. If you have other loads on your
+gateway -- for example if it is also working as a firewall -- then you will
+need to add your own safety factor atop that.</p>
+
+<p>This estimate matches empirical data reasonably well. For example,
+Metheringham's tests, described <a href="#klips.bench">below</a>, show a 733
+topping out between 32 and 36 Mbit/second, pushing data as fast as it can
+down a 100 Mbit link. Our formula suggests you need at least an 800 to handle
+a fully loaded 32 Mbit link. The two results are consistent.</p>
+
+<p>Some examples using this estimation method:</p>
+
+<table border="1" align="center">
+  <tbody>
+    <tr>
+      <th colspan="2">Interface</th>
+      <th colspan="3">Machine speed in MHz</th>
+    </tr>
+    <tr>
+      <th>Type</th>
+      <th>Mbit per<br>
+        second</th>
+      <th>Estimate<br>
+        Mbit*25</th>
+      <th>Minimum IPSEC gateway</th>
+      <th>Minimum with other load
+
+        <p>(e.g. firewall)</p>
+      </th>
+    </tr>
+    <tr>
+      <td>DSL</td>
+      <td align="right">1</td>
+      <td align="right">25 MHz</td>
+      <td rowspan="2">whatever you have</td>
+      <td rowspan="2">133, or better if you have it</td>
+    </tr>
+    <tr>
+      <td>cable modem</td>
+      <td align="right">3</td>
+      <td align="right">75 MHz</td>
+    </tr>
+    <tr>
+      <td><strong>any link, light load</strong></td>
+      <td align="right"><strong>5</strong></td>
+      <td align="right">125 MHz</td>
+      <td>133</td>
+      <td>200+, <strong>almost any surplus machine</strong></td>
+    </tr>
+    <tr>
+      <td>Ethernet</td>
+      <td align="right">10</td>
+      <td align="right">250 MHz</td>
+      <td>surplus 266 or 300</td>
+      <td>500+</td>
+    </tr>
+    <tr>
+      <td><strong>fast link, moderate load</strong></td>
+      <td align="right"><strong>20</strong></td>
+      <td align="right">500 MHz</td>
+      <td>500</td>
+      <td>800+, <strong>any current off-the-shelf PC</strong></td>
+    </tr>
+    <tr>
+      <td>T3 or E3</td>
+      <td align="right">45</td>
+      <td align="right">1125 MHz</td>
+      <td>1200</td>
+      <td>1500+</td>
+    </tr>
+    <tr>
+      <td>fast Ethernet</td>
+      <td align="right">100</td>
+      <td align="right">2500 MHz</td>
+      <td rowspan="2" colspan="2" align="center">// not feasible with 3DES in
+        software on current machines //</td>
+    </tr>
+    <tr>
+      <td>OC3</td>
+      <td align="right">155</td>
+      <td align="right">3875 MHz</td>
+    </tr>
+  </tbody>
+</table>
+
+<p>Such an estimate is far from exact, but should be usable as minimum
+requirement for planning. The key observations are:</p>
+<ul>
+  <li>older <strong>surplus machines</strong> are fine for IPsec gateways at
+    loads up to <strong>5 megabits per second</strong> or so</li>
+  <li>a <strong>mid-range new machine</strong> can handle IPsec at rates up
+    to <strong>20 megabits per second</strong> or more</li>
+</ul>
+  <h3><a name="perf.more">Higher performance alternatives</a></h3>
+
+  <p><a href="glossary.html#AES">AES</a> is a new US government block cipher
+  standard, designed to replace the obsolete <a
+  href="glossary.html#DES">DES</a>. If FreeS/WAN using <a
+  href="glossary.html#3DES">3DES</a> is not fast enough for your application,
+  the AES <a href="web.html#patch">patch</a> may help.</p>
+
+  <p>To date (March 2002) we have had only one <a
+  href="http://lists.freeswan.org/pipermail/users/2002-February/007771.html">mailing
+  list report</a> of measurements with the patch applied. It indicates that,
+  at least for the tested load on that user's network,  <strong>AES roughly
+  doubles IPsec throughput</strong>. If further testing confirms this, it may
+  prove possible to saturate an OC3 link in software on a high-end box.</p>
+
+  <p>Also, some work is being done toward support of <a
+  href="compat.html#hardware">hardware IPsec acceleration</a> which might
+  extend the range of requirements FreeS/WAN could meet.</p>
+
+  <h3>Other considerations</h3>
+
+  <p>CPU speed may be the main issue for IPsec performance, but of course it
+  isn't the only one.</p>
+
+  <p>You need good ethernet cards or other network interface hardware to get
+  the best performance. See this <a
+  href="http://www.ethermanage.com/ethernet/ethernet.html">ethernet
+  information</a> page and this <a href="http://www.scyld.com/diag">Linux
+  network driver</a> page.</p>
+
+  <p>The current FreeS/WAN kernel code is largely single-threaded. It is SMP
+  safe, and will run just fine on a multiprocessor machine (<a
+  href="compat.html#multiprocessor">discussion</a>), but the load within the
+  kernel is not shared effectively. This means that, for example to saturate
+  a T3 -- which needs about a 1200 MHz machine -- you cannot expect something
+  like a dual 800 to do the job. </p>
+
+  <p>On the other hand, SMP machines do tend to share loads well so --
+  provided one CPU is fast enough for the IPsec work -- a multiprocessor
+  machine may be ideal for a gateway with a mixed load.</p>
+
+  <h2><a name="biggate">Many tunnels from a single gateway</a></h2>
+
+  <p>FreeS/WAN allows a single gateway machine to build tunnels to many
+  others. There may, however, be some problems for large numbers as indicated
+  in this message from the mailing list:</p>
+
+<pre>Subject: Re: Maximum number of ipsec tunnels?
+   Date: Tue, 18 Apr 2000
+   From: "John S. Denker" &lt;jsd@research.att.com&gt;
+
+Christopher Ferris wrote:
+
+&gt;&gt; What are the maximum number ipsec tunnels FreeS/WAN can handle??
+
+Henry Spencer wrote:
+
+&gt;There is no particular limit.  Some of the setup procedures currently
+&gt;scale poorly to large numbers of connections, but there are (clumsy)
+&gt;workarounds for that now, and proper fixes are coming.
+
+1) "Large" numbers means anything over 50 or so.  I routinely run boxes
+with about 200 tunnels.  Once you get more than 50 or so, you need to worry
+about several scalability issues:
+
+a) You need to put a "-" sign in syslogd.conf, and rotate the logs daily
+not weekly.
+
+b) Processor load per tunnel is small unless the tunnel is not up, in which
+case a new half-key gets generated every 90 seconds, which can add up if
+you've got a lot of down tunnels.
+
+c) There's other bits of lore you need when running a large number of
+tunnels.  For instance, systematically keeping the .conf file free of
+conflicts requires tools that aren't shipped with the standard freeswan
+package.
+
+d) The pluto startup behavior is quadratic.  With 200 tunnels, this eats up
+several minutes at every restart.   I'm told fixes are coming soon.
+
+2) Other than item (1b), the CPU load depends mainly on the size of the
+pipe attached, not on the number of tunnels.
+</pre>
+
+<p>It is worth noting that item (1b) applies only to repeated attempts to
+re-key a data connection (IPsec SA, Phase 2) over an established keying
+connection (ISAKMP SA, Phase 1). There are two ways to reduce this overhead
+using settings in <a href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</a>:</p>
+<ul>
+  <li>set <var>keyingtries</var> to some small value to limit repetitions</li>
+  <li>set <var>keylife</var> to a short time so that a failing data
+    connection will be cleaned up when the keying connection is reset.</li>
+</ul>
+
+<p>The overheads for establishing keying connections (ISAKMP SAs, Phase 1)
+are lower because for these Pluto does not perform expensive operations
+before receiving a reply from the peer.</p>
+
+<p>A gateway that does a lot of rekeying -- many tunnels and/or low settings
+for tunnel lifetimes -- will also need a lot of <a
+href="glossary.html#random">random numbers</a> from the random(4) driver.</p>
+
+<h2><a name="low-end">Low-end systems</a></h2>
+
+<p><em>Even a 486 can handle a T1 line</em>, according to this mailing list
+message:</p>
+<pre>Subject: Re: linux-ipsec: IPSec Masquerade
+   Date: Fri, 15 Jan 1999 11:13:22 -0500
+   From: Michael Richardson 
+
+. . . A 486/66 has been clocked by Phil Karn to do
+10Mb/s encryption.. that uses all the CPU, so half that to get some CPU,
+and you have 5Mb/s. 1/3 that for 3DES and you get 1.6Mb/s....</pre>
+
+<p>and a piece of mail from project technical lead Henry Spencer:</p>
+<pre>Oh yes, and a new timing point for Sandy's docs...  A P60 -- yes, a 60MHz
+Pentium, talk about antiques -- running a host-to-host tunnel to another
+machine shows an FTP throughput (that is, end-to-end results with a real
+protocol) of slightly over 5Mbit/s either way.  (The other machine is much
+faster, the network is 100Mbps, and the ether cards are good ones... so
+the P60 is pretty definitely the bottleneck.)</pre>
+
+<p>From the above, and from general user experience as reported on the list,
+it seems clear that a cheap surplus machine -- a reasonable 486, a minimal
+Pentium box, a Sparc 5, ... -- can easily handle a home office or a small
+company connection using any of:</p>
+<ul>
+  <li>ADSL service</li>
+  <li>cable modem</li>
+  <li>T1</li>
+  <li>E1</li>
+</ul>
+
+<p>If available, we suggest using a Pentium 133 or better. This should ensure
+that, even under maximum load, IPsec will use less than half the CPU cycles.
+You then have enough left for other things you may want on your gateway --
+firewalling, web caching, DNS and such.</p>
+
+<h2><a name="klips.bench">Measuring KLIPS</a></h2>
+
+<p>Here is some additional data from the mailing list.</p>
+<pre>Subject: FreeSWAN (specically KLIPS) performance measurements
+   Date: Thu, 01 Feb 2001
+   From: Nigel Metheringham &lt;Nigel.Metheringham@intechnology.co.uk&gt;
+
+I've spent a happy morning attempting performance tests against KLIPS 
+(this is due to me not being able to work out the CPU usage of KLIPS so 
+resorting to the crude measurements of maximum throughput to give a 
+baseline to work out loading of a box).
+
+Measurements were done using a set of 4 boxes arranged in a line, each 
+connected to the next by 100Mbit duplex ethernet.  The inner 2 had an 
+ipsec tunnel between them (shared secret, but I was doing measurements 
+when the tunnel was up and running - keying should not be an issue 
+here).  The outer pair of boxes were traffic generators or traffic sink.
+
+The crypt boxes are Compaq DL380s - Uniprocessor PIII/733 with 256K 
+cache.  They have 128M main memory.  Nothing significant was running on 
+the boxes other than freeswan.  The kernel was a 2.2.19pre7 patched 
+with freeswan and ext3.
+
+Without an ipsec tunnel in the chain (ie the 2 inner boxes just being 
+100BaseT routers), throughput (measured with ttcp) was between 10644 
+and 11320 KB/sec
+
+With an ipsec tunnel in place, throughput was between 3268 and 3402 
+KB/sec
+
+These measurements are for data pushed across a TCP link, so the 
+traffic on the wire between the 2 ipsec boxes would have been higher 
+than this....
+
+vmstat (run during some other tests, so not affecting those figures) on 
+the encrypting box shows approx 50% system &amp; 50% idle CPU - which I 
+don't believe at all.  Interactive feel of the box was significantly 
+sluggish.
+
+I also tried running the kernel profiler (see man readprofile) during 
+test runs.
+
+A box doing primarily decrypt work showed basically nothing happening - 
+I assume interrupts were off.
+A box doing encrypt work showed the following:-
+ Ticks Function                                   Load
+ ~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~    ~~~~~~
+   956 total                                      0.0010
+   532 des_encrypt2                               0.1330
+   110 MD5Transform                               0.0443
+    97 kmalloc                                    0.1880
+    39 des_encrypt3                               0.1336
+    23 speedo_interrupt                           0.0298
+    14 skb_copy_expand                            0.0250
+    13 ipsec_tunnel_start_xmit                    0.0009
+    13 Decode                                     0.1625
+    11 handle_IRQ_event                           0.1019
+    11 .des_ncbc_encrypt_end                      0.0229
+    10 speedo_start_xmit                          0.0188
+     9 satoa                                      0.0225
+     8 kfree                                      0.0118
+     8 ip_fragment                                0.0121
+     7 ultoa                                      0.0365
+     5 speedo_rx                                  0.0071
+     5 .des_encrypt2_end                          5.0000
+     4 _stext                                     0.0140
+     4 ip_fw_check                                0.0035
+     2 rj_match                                   0.0034
+     2 ipfw_output_check                          0.0200
+     2 inet_addr_type                             0.0156
+     2 eth_copy_and_sum                           0.0139
+     2 dev_get                                    0.0294
+     2 addrtoa                                    0.0143
+     1 speedo_tx_buffer_gc                        0.0024
+     1 speedo_refill_rx_buf                       0.0022
+     1 restore_all                                0.0667
+     1 number                                     0.0020
+     1 net_bh                                     0.0021
+     1 neigh_connected_output                     0.0076
+     1 MD5Final                                   0.0083
+     1 kmem_cache_free                            0.0016
+     1 kmem_cache_alloc                           0.0022
+     1 __kfree_skb                                0.0060
+     1 ipsec_rcv                                  0.0001
+     1 ip_rcv                                     0.0014
+     1 ip_options_fragment                        0.0071
+     1 ip_local_deliver                           0.0023
+     1 ipfw_forward_check                         0.0139
+     1 ip_forward                                 0.0011
+     1 eth_header                                 0.0040
+     1 .des_encrypt3_end                          0.0833
+     1 des_decrypt3                               0.0034
+     1 csum_partial_copy_generic                  0.0045
+     1 call_out_firewall                          0.0125
+
+Hope this data is helpful to someone... however the lack of visibility 
+into the decrypt side makes things less clear</pre>
+
+<h2><a name="speed.compress">Speed with compression</a></h2>
+
+<p>Another user reported some results for connections with and without IP
+compression:</p>
+<pre>Subject: [Users] Speed with compression
+   Date: Fri, 29 Jun 2001
+   From: John McMonagle &lt;johnm@advocap.org&gt;
+
+Did a couple tests with compression using the new 1.91 freeswan.
+
+Running between 2 sites with cable modems.  Both  using approximately
+130 mhz pentium.
+
+Transferred files with ncftp.
+
+Compressed file was a 6mb compressed  installation file.
+Non compressed was 18mb /var/lib/rpm/packages.rpm
+
+                            Compressed vpn          regular vpn
+Compress file                42.59 kBs               42.08 kBs
+regular file                110.84 kBs               41.66 kBs
+
+Load  was about 0 either way.
+Ping times were very similar  a bit above 9 ms.
+
+Compression looks attractive to me.</pre>
+Later in the same thread, project technical lead Henry Spencer added:
+<pre>&gt; is there a reason not to switch compression on?  I have large gateway boxes
+&gt; connecting 3 connections, one of them with a measly DS1 link...
+
+Run some timing tests with and without, with data and loads representative
+of what you expect in production.  That's the definitive way to decide. 
+If compression is a net loss, then obviously, leave it turned off.  If it
+doesn't make much difference, leave it off for simplicity and hence
+robustness.  If there's a substantial gain, by all means turn it on. 
+
+If both ends support compression and can successfully negotiate a
+compressed connection (trivially true if both are FreeS/WAN 1.91), then
+the crucial question is CPU cycles. 
+
+Compression has some overhead, so one question is whether *your* data
+compresses well enough to save you more CPU cycles (by reducing the volume
+of data going through CPU-intensive encryption/decryption) than it costs
+you.  Last time I ran such tests on data that was reasonably compressible
+but not deliberately contrived to be so, this generally was not true --
+compression cost extra CPU cycles -- so compression was worthwhile only if
+the link, not the CPU, was the bottleneck.  However, that was before the
+slow-compression bug was fixed.  I haven't had a chance to re-run those
+tests yet, but it sounds like I'd probably see a different result. </pre>
+The bug he refers to was a problem with the compression libraries that had us
+using C code, rather than assembler, for compression. It was fixed before
+1.91.
+
+<h2><a name="methods">Methods of measuring</a></h2>
+
+<p>If you want to measure the loads FreeS/WAN puts on a system, note that
+tools such as top or measurements such as load average are more-or-less
+useless for this. They are not designed to measure something that does most
+of its work inside the kernel.</p>
+
+<p>Here is a message from FreeS/WAN kernel programmer Richard Guy Briggs on
+this:</p>
+<pre>&gt; I have a batch of boxes doing Freeswan stuff.
+&gt; I want to measure the CPU loading of the Freeswan tunnels, but am 
+&gt; having trouble seeing how I get some figures out...
+&gt; 
+&gt;  - Keying etc is in userspace so will show up on the per-process
+&gt;    and load average etc (ie pluto's load)
+
+Correct.
+
+&gt;  - KLIPS is in the kernel space, and does not show up in load average
+&gt;    I think also that the KLIPS per-packet processing stuff is running
+&gt;    as part of an interrupt handler so it does not show up in the
+&gt;    /proc/stat system_cpu or even idle_cpu figures
+
+It is not running in interrupt handler.  It is in the bottom half.
+This is somewhere between user context (careful, this is not
+userspace!) and hardware interrupt context.
+
+&gt; Is this correct, and is there any means of instrumenting how much the 
+&gt; cpu is being loaded - I don't like the idea of a system running out of 
+&gt; steam whilst still showing 100% idle CPU :-)
+
+vmstat seems to do a fairly good job, but use a running tally to get a
+good idea.  A one-off call to vmstat gives different numbers than a
+running stat.  To do this, put an interval on your vmstat command
+line.</pre>
+and another suggestion from the same thread:
+<pre>Subject: Re: Measuring the CPU usage of Freeswan
+   Date: Mon, 29 Jan 2001
+   From: Patrick Michael Kane &lt;modus@pr.es.to&gt;
+ 
+The only truly accurate way to accurately track FreeSWAN CPU usage is to use
+a CPU soaker. You run it on an unloaded system as a benchmark, then start up
+FreeSWAN and take the difference to determine how much FreeSWAN is eating.
+I believe someone has done this in the past, so you may find something in
+the FreeSWAN archives.  If not, someone recently posted a URL to a CPU
+soaker benchmark tool on linux-kernel.</pre>
+</body>
+</html>
diff --git a/doc/src/policy-groups-table.html b/doc/src/policy-groups-table.html
new file mode 100644
index 000000000..8e84809cf
--- /dev/null
+++ b/doc/src/policy-groups-table.html
@@ -0,0 +1,297 @@
+<!DOCTYPE html PUBLIC "-//w3c//dtd html 4.0 transitional//en">
+<html>
+<head>
+            
+  <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+            
+  <meta name="Author" content="Richard Guy Briggs">
+            
+  <meta name="GENERATOR" content="Mozilla/4.78 [en] (X11; U; Linux 2.4.18 i686) [Netscape]">
+  <title></title>
+</head>
+  <body>
+Policy Groups Table<br>
+<br>
+This table lists all the policy group combinations and expected packet flows.<br>
+<br>
+<br>
+   
+<table border="1" cols="14" width="100%" nosave="">
+   <tbody>
+      <tr>
+   <th bgcolor="#cccccc">policy</th>
+    <th bgcolor="#cccccc"><br>
+        </th>
+    <th bgcolor="#cccccc" colspan="2">none</th>
+      <th bgcolor="#cccccc" colspan="2">clear</th>
+      <th bgcolor="#cccccc" colspan="2">clear-or-private</th>
+      <th bgcolor="#cccccc" colspan="2">private-or-clear</th>
+      <th bgcolor="#cccccc" colspan="2">private</th>
+      <th bgcolor="#cccccc" colspan="2">block</th>
+     </tr>
+    <tr>
+   <th bgcolor="#cccccc"><br>
+        </th>
+    <th bgcolor="#cccccc">key?</th>
+    <th bgcolor="#cccccc">no</th>
+    <th bgcolor="#cccccc">yes</th>
+    <th bgcolor="#cccccc">no</th>
+    <th bgcolor="#cccccc">yes</th>
+    <th bgcolor="#cccccc">no</th>
+    <th bgcolor="#cccccc">yes</th>
+    <th bgcolor="#cccccc">no</th>
+    <th bgcolor="#cccccc">yes</th>
+    <th bgcolor="#cccccc">no</th>
+    <th bgcolor="#cccccc">yes</th>
+    <th bgcolor="#cccccc">no</th>
+    <th bgcolor="#cccccc">yes</th>
+   </tr>
+    <tr>
+   <th bgcolor="#cccccc" rowspan="2">none</th>
+    <th bgcolor="#cccccc">no</th>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c,f</td>
+    <td>c,f</td>
+    <td>c,f</td>
+    <td>c,f</td>
+   </tr>
+    <tr>
+    <th bgcolor="#cccccc">yes</th>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c,f?</td>
+    <td>c,f?</td>
+    <td>c,f</td>
+    <td>c,f</td>
+    <td>c,f</td>
+    <td>c,f</td>
+   </tr>
+    <tr>
+   <th bgcolor="#cccccc" rowspan="2">clear</th>
+    <th bgcolor="#cccccc">no</th>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c,c(f?)</td>
+    <td>c,f</td>
+    <td>c,f</td>
+    <td>c,f</td>
+    <td>c,f</td>
+   </tr>
+    <tr>
+    <th bgcolor="#cccccc">yes</th>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c,f?</td>
+    <td>c,f?</td>
+    <td>c,f</td>
+    <td>c,f</td>
+    <td>c,f</td>
+    <td>c,f</td>
+   </tr>
+    <tr>
+   <th bgcolor="#cccccc" rowspan="2">clear-or-private</th>
+    <th bgcolor="#cccccc">no</th>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c,f?</td>
+    <td>c,c(f?)</td>
+    <td>c,f</td>
+    <td>c,f</td>
+    <td>c,f</td>
+    <td>c,f</td>
+   </tr>
+    <tr>
+    <th bgcolor="#cccccc">yes</th>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c</td>
+    <td>c,f?</td>
+    <td>c,e</td>
+    <td>c,f</td>
+    <td>c,e</td>
+    <td>c,f</td>
+    <td>c,f</td>
+   </tr>
+    <tr>
+   <th bgcolor="#cccccc" rowspan="2">private-or-clear</th>
+    <th bgcolor="#cccccc">no</th>
+    <td>t,c</td>
+    <td>t,f?</td>
+    <td>t,c</td>
+    <td>t,f?</td>
+    <td>t,c</td>
+    <td>t,f?</td>
+    <td>t,f?</td>
+    <td>t,f?</td>
+    <td>t,f</td>
+    <td>t,f</td>
+    <td>t,f</td>
+    <td>t,f</td>
+   </tr>
+    <tr>
+    <th bgcolor="#cccccc">yes</th>
+    <td>t,c</td>
+    <td>t,f?</td>
+    <td>t,c</td>
+    <td>t,f?</td>
+    <td>t,c</td>
+    <td>t,e</td>
+    <td>t,c(f?)</td>
+    <td>t,e</td>
+    <td>t,f</td>
+    <td>t,e</td>
+    <td>t,f</td>
+    <td>t,f</td>
+   </tr>
+    <tr>
+   <th bgcolor="#cccccc" rowspan="2">private</th>
+    <th bgcolor="#cccccc">no</th>
+    <td>t,f</td>
+    <td>t,f</td>
+    <td>t,f</td>
+    <td>t,f</td>
+    <td>t,f</td>
+    <td>t,f</td>
+    <td>t,f</td>
+    <td>t,f</td>
+    <td>t,f</td>
+    <td>t,f</td>
+    <td>t,f</td>
+    <td>t,f</td>
+   </tr>
+    <tr>
+    <th bgcolor="#cccccc">yes</th>
+    <td>t,f</td>
+    <td>t,f</td>
+    <td>t,f</td>
+    <td>t,f</td>
+    <td>t,f</td>
+    <td>t,e</td>
+    <td>t,f</td>
+    <td>t,e</td>
+    <td>t,f</td>
+    <td>t,e</td>
+    <td>t,f</td>
+    <td>t,f</td>
+   </tr>
+    <tr>
+   <th bgcolor="#cccccc" rowspan="2">block</th>
+    <th bgcolor="#cccccc">no</th>
+    <td>f</td>
+    <td>f</td>
+    <td>f</td>
+    <td>f</td>
+    <td>f</td>
+    <td>f</td>
+    <td>f</td>
+    <td>f</td>
+    <td>f</td>
+    <td>f</td>
+    <td>f</td>
+    <td>f</td>
+   </tr>
+    <tr>
+    <th bgcolor="#cccccc">yes</th>
+    <td>f</td>
+    <td>f</td>
+    <td>f</td>
+    <td>f</td>
+    <td>f</td>
+    <td>f</td>
+    <td>f</td>
+    <td>f</td>
+    <td>f</td>
+    <td>f</td>
+    <td>f</td>
+    <td>f</td>
+   </tr>
+         
+  </tbody>  
+</table>
+    <br>
+  &nbsp;   
+<table border="1" cols="2" nosave="">
+   <tbody>
+      <tr nosave="">
+   <th nosave="">legend</th>
+    <th>packet fate</th>
+   </tr>
+    <tr>
+   <td>c</td>
+    <td>clear</td>
+   </tr>
+    <tr>
+   <td>f</td>
+    <td>fail</td>
+   </tr>
+    <tr>
+   <td>e</td>
+    <td>encrypt</td>
+   </tr>
+    <tr>
+   <td>t</td>
+    <td>trap</td>
+   </tr>
+    <tr>
+      <td valign="Top">c,f<br>
+      </td>
+      <td valign="Top">first packet clear, then fail<br>
+      </td>
+    </tr>
+    <tr>
+      <td valign="Top">c,e<br>
+      </td>
+      <td valign="Top">first packet clear, then encrypt<br>
+      </td>
+    </tr>
+    <tr>
+      <td valign="Top">t,f<br>
+      </td>
+      <td valign="Top">trap, then fail<br>
+      </td>
+    </tr>
+    <tr>
+      <td valign="Top">t,c<br>
+      </td>
+      <td valign="Top">trap, then clear<br>
+      </td>
+    </tr>
+    <tr>
+      <td valign="Top">t,e<br>
+      </td>
+      <td valign="Top">trap, then encrypt<br>
+      </td>
+    </tr>
+         
+  </tbody>  
+</table>
+      
+</body>
+</html>
diff --git a/doc/src/policygroups.html b/doc/src/policygroups.html
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+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>Configuring FreeS/WAN with policy groups</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, encryption, cryptography, FreeS/WAN, FreeSWAN">
+  <!--
+
+  Written by Claudia Schmeing for the Linux FreeS/WAN project
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: policygroups.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+
+<body>
+<h1>How to Configure Linux FreeS/WAN with Policy Groups</h1>
+
+
+<A NAME="policygroups"></A>
+
+<H2>What are Policy Groups?</H2>
+
+
+<P><STRONG>Policy Groups</STRONG> are an elegant general mechanism 
+to configure FreeS/WAN. They are useful for
+many FreeS/WAN users.</P>
+
+<P>In previous FreeS/WAN versions, you needed to configure each IPsec 
+connection explicitly, on both local and remote hosts.
+ This could become complex.</P>
+
+<P>By contrast, Policy Groups allow you to set local IPsec policy
+for lists of remote hosts and networks,
+simply by listing the hosts and networks which you wish to 
+have special treatment in one of several Policy Group files.
+FreeS/WAN then internally creates the connections 
+needed to implement each policy.</P>
+
+<P>In the next section we describe our five Base Policy Groups, which
+you can use to configure IPsec in many useful ways. Later, we will 
+show you how to create an IPsec VPN using one line of configuration for 
+each remote host or network.</P>
+
+
+<A NAME="builtin_policygroups"></A><H3>Built-In Security Options</H3>
+
+<P>FreeS/WAN offers these Base Policy Groups:</P>
+
+<DL>
+
+<DT>private</DT>
+
+<DD>
+FreeS/WAN only communicates privately with the listed 
+<A HREF="glossary.html#CIDR">CIDR</A> blocks.
+If needed, FreeS/WAN attempts to create a connection opportunistically.
+If this fails, FreeS/WAN blocks communication.
+Inbound blocking is assumed to be done by the firewall. FreeS/WAN offers 
+firewall hooks but no modern firewall rules to help with inbound blocking.
+
+</DD>
+
+<DT>private-or-clear</DT>
+<DD>
+
+FreeS/WAN prefers private communication with the listed CIDR blocks.
+If needed, FreeS/WAN attempts to create a connection opportunistically.
+If this fails, FreeS/WAN allows traffic in the clear.
+
+</DD>
+
+<DT>clear-or-private</DT>
+
+<DD>
+FreeS/WAN communicates cleartext with the listed CIDR blocks, but
+also accepts inbound OE connection requests from them.
+Also known as <A HREF="glossary.html#passive.OE">passive OE (pOE)</A>, 
+this policy may be used to create an 
+<A HREF="glossary.html#responder">opportunistic responder</A>.
+</DD>
+
+<DT>clear</DT>
+<DD>
+FreeS/WAN only communicates cleartext with the listed CIDR blocks.
+</DD>
+
+<DT>block</DT>
+<DD>FreeS/WAN blocks traffic to and from and the listed CIDR blocks.
+Inbound blocking is assumed to be done by the firewall. FreeS/WAN offers 
+firewall hooks but no modern firewall rules to help with inbound blocking.
+<!-- also called "blockdrop".-->
+
+</DD>
+
+</DL>
+
+<A NAME="policy.group.notes"></A><P>Notes:</P>
+
+<UL>
+<LI>Base Policy Groups apply to communication with this host only.</LI>
+<LI>The most specific rule (whether policy or pre-configured connection) 
+applies.
+This has several practical applications:
+<UL>
+<LI>If CIDR blocks overlap, FreeS/WAN chooses 
+the most specific applicable block.</LI>
+<LI>This decision also takes into account any pre-configured connections
+you may have.</LI>
+<LI>If the most specific connection is a pre-configured connection,
+the following procedure applies. If that connection is up, it will be
+used. If it is routed, it will be brought up. If it is added, 
+no action will be taken.</LI>
+</UL>
+<LI>Base Policy Groups are created using built-in connections.
+Details in 
+<A HREF="manpage.d/ipsec.conf.5.html">man ipsec.conf</A>.</LI>
+<LI>All Policy Groups are bidirectional. 
+<A HREF="src/policy-groups-table.html">This chart</A> shows some technical 
+details.
+FreeS/WAN does not support one-way encryption, since it can give users
+a false sense of security.</LI>
+</UL>
+
+
+<H2>Using Policy Groups</H2>
+
+<P>The Base Policy Groups which build IPsec connections rely on Opportunistic
+Encryption. To use the following examples, you 
+must first become OE-capable, as described 
+in our <A HREF="quickstart.html#quickstart">quickstart guide</A>.
+
+<A NAME="example1"></A><H3>Example 1: Using a Base Policy Group</H3>
+
+<P>Simply place CIDR blocks (<A HREF="#dnswarning">names</A>, 
+IPs or IP ranges) in /etc/ipsec.d/policies/<VAR>[groupname]</VAR>, 
+and reread the policy group files.</P> 
+
+<P>For example, the <VAR>private-or-clear</VAR> policy tells 
+FreeS/WAN to prefer encrypted communication to the listed CIDR blocks.
+Failing that, it allows talk in the clear.</P>
+
+<P>To make this your default policy, place
+<A HREF="glossary.html#fullnet">fullnet</A>
+in the <VAR>private-or-clear</VAR> policy group file:</P>
+
+<PRE>    [root@xy root]# cat /etc/ipsec.d/policies/private-or-clear
+    # This file defines the set of CIDRs (network/mask-length) to which
+    # communication should be private, if possible, but in the clear otherwise.
+    ....
+    0.0.0.0/0</PRE>
+
+<P>and reload your policies with</P>
+
+<PRE>    ipsec auto --rereadgroups</PRE>
+
+<P>Use <A HREF="quickstart.html#opp.test">this test</A> to verify 
+opportunistic connections.</P>
+
+
+
+<A NAME="example2"></A><H3>Example 2: Defining IPsec Security Policy 
+with Groups</H3>
+
+<P>Defining IPsec security policy with Base Policy Groups is like creating
+a shopping list: just put CIDR blocks in the appropriate group files. 
+For example:</P>
+
+
+<PRE>    [root@xy root]# cd /etc/ipsec.d/policies
+    [root@xy policies]# cat private
+        192.0.2.96/27              # The finance department
+        192.0.2.192/29             # HR
+	192.0.2.12                 # HR gateway
+        irc.private.example.com    # Private IRC server
+  
+    [root@xy policies]# cat private-or-clear
+        0.0.0.0/0                  # My default policy: try to encrypt.
+
+    [root@xy policies]# cat clear
+        192.0.2.18/32              # My POP3 server
+        192.0.2.19/32              # My Web proxy
+
+    [root@xy policies]# cat block
+        spamsource.example.com</PRE>
+
+<P>To make these settings take effect, type:</P>
+<PRE>    ipsec auto --rereadgroups</PRE>
+
+
+<P>Notes:</P>
+<UL>
+<LI>For opportunistic connection attempts to succeed, all participating
+FreeS/WAN hosts and gateways must be configured for OE.</LI>
+<LI>Examples 3 through 5 show how to implement a detailed <VAR>private</VAR>
+policy.</LI>
+<LI>
+<A NAME="dnswarning"></A>
+<FONT COLOR=RED>Warning:</FONT> Using DNS names in policy files and ipsec.conf 
+can be tricky. If the name does not resolve, the policy will not be 
+implemented for that name.
+It is therefore safer either to use IPs, or to put any critical names 
+in /etc/hosts.
+We plan to implement periodic DNS retry to help with this.
+<BR>
+Names are resolved at FreeS/WAN startup, or when the policies are reloaded.
+Unfortunately, name lookup can hold up the startup process. 
+If you have fast DNS servers, the problem may be less severe.
+</LI>
+</UL>
+
+
+<A HREF="example3"></A><H3>Example 3: Creating a Simple IPsec VPN with the 
+<VAR>private</VAR> Group</H3>
+
+
+<P>You can create an IPsec VPN between several hosts, with
+only one line of configuration per host, using the <VAR>private</VAR>
+policy group.</P>
+
+<P>First, use our <A HREF="quickstart.html">quickstart 
+guide</A> to set up each participating host
+with a FreeS/WAN install and OE.</P>
+
+<P>In one host's <VAR>/etc/ipsec.d/policies/private</VAR>, 
+list the peers to which you wish to protect traffic.
+For example:</P>
+
+<PRE>    [root@xy root]# cd /etc/ipsec.d/policies
+    [root@xy policies]# cat private
+        192.0.2.9              # several hosts at example.com
+        192.0.2.11             
+        192.0.2.12                 
+        irc.private.example.com 
+</PRE>
+
+<P>Copy the <VAR>private</VAR> file to each host. Remove the local host, and 
+add the initial host.</P>
+
+<PRE>    scp2 /etc/ipsec.d/policies/private root@192.0.2.12:/etc/ipsec.d/policies/private</PRE>
+
+<P>On each host, reread the policy groups with</P>
+
+<PRE>    ipsec auto --rereadgroups</PRE>
+
+
+<P>That's it! You're configured.</P>
+
+<P>Test by pinging between two hosts. After a second or two, 
+traffic should flow, and</P>
+
+<PRE>    ipsec eroute</PRE>
+
+<P>should yield something like</P>
+
+<PRE>    192.0.2.11/32   -> 192.0.2.8/32  => tun0x149f@192.0.2.8</PRE>
+
+<P>where your host IPs are substituted for 192.0.2.11 and 192.0.2.8.</P>
+
+<P>If traffic does not flow, there may be an error in your OE setup. 
+Revisit our <A HREF="quickstart.html">quickstart guide</A>.</P>
+
+
+<P>Our next two examples show you how to add subnets to this IPsec VPN.</P>
+
+
+<A NAME="example4"></A><H3>Example 4: New Policy Groups to Protect a
+Subnet</H3>
+
+<P>To protect traffic to a subnet behind your FreeS/WAN gateway, 
+you'll need additional DNS records, and new policy groups.
+To set up the DNS, see our <A HREF="quickstart.html#opp.gate">quickstart
+guide</A>. To create five new policy groups for your subnet, 
+copy these connections to <VAR>/etc/ipsec.conf</VAR>. 
+Substitute your subnet's IPs for 192.0.2.128/29.</P>
+
+<PRE>
+conn private-net
+    also=private  # inherits settings (eg. auto=start) from built in conn
+    leftsubnet=192.0.2.128/29  # your subnet's IPs here
+
+conn private-or-clear-net
+    also=private-or-clear
+    leftsubnet=192.0.2.128/29
+
+conn clear-or-private-net
+    also=clear-or-private
+    leftsubnet=192.0.2.128/29
+
+conn clear-net
+    also=clear
+    leftsubnet=192.0.2.128/29
+
+conn block-net
+    also=block
+    leftsubnet=192.0.2.128/29
+</PRE>
+
+<P>Copy the gateway's files to serve as the initial policy group files for the
+new groups:</P>
+
+<PRE>
+    cp -p /etc/ipsec.d/policies/private /etc/ipsec.d/policies/private-net
+    cp -p /etc/ipsec.d/policies/private-or-clear /etc/ipsec.d/policies/private-or-clear-net
+    cp -p /etc/ipsec.d/policies/clear-or-private /etc/ipsec.d/policies/clear-or-private-net
+    cp -p /etc/ipsec.d/policies/clear /etc/ipsec.d/policies/clear-net
+    cp -p /etc/ipsec.d/policies/block /etc/ipsec.d/policies/block
+</PRE>
+
+<P><STRONG>Tip: Since a missing policy group file is equivalent to a file with 
+no entries, you need only create files for the connections 
+you'll use.</STRONG></P>
+
+<P>To test one of your new groups, place the fullnet 0.0.0.0/0 in 
+<VAR>private-or-clear-net</VAR>. 
+Perform the subnet test in
+<A HREF="quickstart.html#opp.test">our quickstart guide</A>. You should
+see a connection, and</P>
+
+<PRE>    ipsec eroute</PRE>
+
+<P>should include an entry which mentions the subnet node's IP and the 
+OE test site IP, like this:</P>
+
+<PRE>    192.0.2.131/32   -> 192.139.46.77/32  => tun0x149f@192.0.2.11</PRE>
+
+
+<A HREF="example5"></A><H3>Example 5: Adding a Subnet to the VPN</H3>
+
+<P>Suppose you wish to secure traffic to a subnet 192.0.2.192/29
+behind a FreeS/WAN box 192.0.2.12.</P>
+
+<P>First, add DNS entries to configure 192.0.2.12 as an opportunistic 
+gateway for that subnet. Instructions are in
+ our <A HREF="quickstart.html#opp.gate">quickstart guide</A>.
+Next, create a <VAR>private-net</VAR> group on 192.0.2.12 as described in 
+<A HREF="#example4">Example 4</A>.
+</P>
+
+<P>On each other host, add the subnet 192.0.2.192/29 to <VAR>private</VAR>,
+yielding for example</P>
+
+<PRE>    [root@xy root]# cd /etc/ipsec.d/policies
+    [root@xy policies]# cat private
+        192.0.2.9              # several hosts at example.com
+        192.0.2.11
+        192.0.2.12             # HR department gateway
+        192.0.2.192/29         # HR subnet
+        irc.private.example.com
+</PRE>
+
+
+<P>and reread policy groups with </P>
+
+<PRE>    ipsec auto --rereadgroups</PRE>
+
+<P>That's all the configuration you need.</P>
+
+<P>Test your VPN by pinging from a machine on 192.0.2.192/29 to any other host:
+</P>
+
+<PRE>    [root@192.0.2.194]# ping 192.0.2.11</PRE>
+
+
+<P>After a second or two, traffic should flow, and</P>
+
+<PRE>    ipsec eroute</PRE>
+
+<P>should yield something like</P>
+
+<PRE>    192.0.2.11/32   -> 192.0.2.194/32  => tun0x149f@192.0.2.12
+</PRE>
+
+<P>Key:</P>
+<TABLE>
+<TR><TD>1.</TD>
+    <TD>192.0.2.11/32</TD>
+    <TD>Local start point of the protected traffic.
+    </TD></TR>
+<TR><TD>2.</TD>
+    <TD>192.0.2.194/32</TD>
+    <TD>Remote end point of the protected traffic.
+    </TD></TR>
+<TR><TD>3.</TD>
+    <TD>192.0.2.12</TD>
+    <TD>Remote FreeS/WAN node (gateway or host).
+	May be the same as (2).
+   </TD></TR>
+<TR><TD>4.</TD>
+    <TD>[not shown]</TD>
+    <TD>Local FreeS/WAN node (gateway or host),
+	where you've produced the output.
+	May be the same as (1).
+   </TD></TR>
+</TABLE>
+
+<P>For additional assurance, you can verify with a packet sniffer 
+that the traffic is being encrypted.</P>
+
+
+<P>Note</P>
+<UL>
+<LI>Because strangers may also connect via OE, 
+this type of VPN may require a stricter firewalling policy than a 
+conventional VPN.</LI></UL>
+
+
+
+<H2>Appendix</H2>
+
+<A NAME="hiddenconn"></A><H3>Our Hidden Connections</H3>
+
+
+<P>Our Base Policy Groups are created using hidden connections.
+These are spelled out in 
+<A HREF="manpage.d/ipsec.conf.5.html">man ipsec.conf</A>
+ and defined in <VAR>/usr/local/lib/ipsec/_confread</VAR>.
+</P>
+
+
+<A NAME="custom_policygroups"></A><H3>Custom Policy Groups</H3>
+
+<P>A policy group is built using a special connection description
+in <VAR>ipsec.conf</VAR>, which:</P>
+
+<UL>
+<LI>is <STRONG>generic</STRONG>. It uses 
+<VAR>right=[%group|%opportunisticgroup]</VAR> rather than specific IPs. 
+The connection is cloned for every name or IP range listed in its Policy Group
+file.</LI>
+<LI>often has a <STRONG>failure rule</STRONG>. This rule, written
+<VAR>failureshunt=[passthrough|drop|reject|none]</VAR>, tells FreeS/WAN 
+what to do with packets for these CIDRs if it fails to establish the connection.
+Default is <VAR>none</VAR>.
+</LI>
+</UL>
+
+<P>To create a new group:</P>
+<OL>
+<LI>Create its connection definition in <VAR>ipsec.conf</VAR>.</LI>
+<LI>Create a Policy Group file in <VAR>/etc/ipsec.d/policies</VAR> 
+with the same name as your connection.
+</LI>
+<LI>Put a CIDR block in that file.</LI>
+<LI>Reread groups with <VAR>ipsec auto --rereadgroups</VAR>.</LI>
+<LI>Test: <VAR>ping</VAR> to activate any OE connection, and view
+results with <VAR>ipsec eroute</VAR>.</LI>
+</OL>
+
+<A NAME="disable_oe"></A>
+<A NAME="disable_policygroups"></A><H3>Disabling Opportunistic Encryption</H3>
+
+<P>To disable OE (eg. policy groups and packetdefault), cut and paste the following lines 
+to <VAR>/etc/ipsec.conf</VAR>:</P>
+
+<PRE>conn block
+    auto=ignore
+
+conn private
+    auto=ignore
+
+conn private-or-clear
+    auto=ignore
+
+conn clear-or-private
+    auto=ignore
+
+conn clear
+    auto=ignore
+
+conn packetdefault
+    auto=ignore</PRE>
+
+<P>Restart FreeS/WAN so that the changes take effect:</P>
+
+<PRE>    ipsec setup restart</PRE>
+
+</body>
+</html>
+
+
diff --git a/doc/src/politics.html b/doc/src/politics.html
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+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>History and politics of cryptography</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, FreeSWAN, cryptography, history, politics">
+  <!--
+
+  Written by Sandy Harris for the Linux FreeS/WAN project
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: politics.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+
+<body>
+<h1><a name="politics">History and politics of cryptography</a></h1>
+
+<p>Cryptography has a long and interesting history, and has been the subject
+of considerable political controversy.</p>
+
+<h2><a name="intro.politics">Introduction</a></h2>
+
+<h3>History</h3>
+
+<p>The classic book on the history of cryptography is David Kahn's <a
+href="biblio.html#Kahn">The Codebreakers</a>. It traces codes and
+codebreaking from ancient Egypt to the 20th century.</p>
+
+<p>Diffie and Landau <a href="biblio.html#diffie">Privacy on the Line: The
+Politics of Wiretapping and Encryption</a> covers the history from the First
+World War to the 1990s, with an emphasis on the US.</p>
+
+<h4>World War II</h4>
+
+<p>During the Second World War, the British "Ultra" project achieved one of
+the greatest intelligence triumphs in the history of warfare, breaking many
+Axis codes. One major target was the Enigma cipher machine, a German device
+whose users were convinced it was unbreakable. The American "Magic" project
+had some similar triumphs against Japanese codes.</p>
+
+<p>There are many books on this period. See our bibliography for several. Two
+I particularly like are:</p>
+<ul>
+  <li>Andrew Hodges has done a superb <a
+    href="http://www.turing.org.uk/book/">biography</a> of Alan Turing, a key
+    player among the Ultra codebreakers. Turing was also an important
+    computer pioneer. The terms <a
+    href="http://www.abelard.org/turpap/turpap.htm">Turing test</a> and <a
+    href="http://plato.stanford.edu/entries/turing-machine/">Turing
+    machine</a> are named for him, as is the <a
+    href="http://www.acm.org">ACM</a>'s highest technical <a
+    href="http://www.acm.org/awards/taward.html">award</a>.</li>
+  <li>Neal Stephenson's <a href="biblio.html#neal">Cryptonomicon</a> is a
+    novel with cryptography central to the plot. Parts of it take place
+    during WW II, other parts today.</li>
+</ul>
+
+<p>Bletchley Park, where much of the Ultra work was done, now has a museum
+and a <a href="http://www.bletchleypark.org.uk/">web site</a>.</p>
+
+<p>The Ultra work introduced three major innovations.</p>
+<ul>
+  <li>The first break of Enigma was achieved by Polish Intelligence in 1931.
+    Until then most code-breakers had been linguists, but a different
+    approach was needed to break machine ciphers. Polish Intelligence
+    recruited bright young mathematicians to crack the "unbreakable" Enigma.
+    When war came in 1939, the Poles told their allies about this, putting
+    Britain on the road to Ultra. The British also adopted a mathematical
+    approach.</li>
+  <li>Machines were extensively used in the attacks. First the Polish "Bombe"
+    for attacking Enigma, then British versions of it, then machines such as
+    Collosus for attacking other codes. By the end of the war, some of these
+    machines were beginning to closely resemble digital computers. After the
+    war, a team at Manchester University, several old Ultra hands included,
+    built one of the world's first actual general-purpose digital
+  computers.</li>
+  <li>Ultra made codebreaking a large-scale enterprise, producing
+    intelligence on an industrial scale. This was not a "black chamber", not
+    a hidden room in some obscure government building with a small crew of
+    code-breakers. The whole operation -- from wholesale interception of
+    enemy communications by stations around the world, through large-scale
+    code-breaking and analysis of the decrypted material (with an enormous
+    set of files for cross-referencing), to delivery of intelligence to field
+    commanders -- was huge, and very carefully managed.</li>
+</ul>
+
+<p>So by the end of the war, Allied code-breakers were expert at large-scale
+mechanised code-breaking. The payoffs were enormous.</p>
+
+<h4><a name="postwar">Postwar and Cold War</a></h4>
+
+<p>The wartime innovations were enthusiastically adopted by post-war and Cold
+War signals intelligence agencies. Presumably many nations now have some
+agency capable of sophisticated attacks on communications security, and quite
+a few engage in such activity on a large scale.</p>
+
+<p>America's <a href="glossary.html#NSA">NSA</a>, for example, is said to be
+both the world's largest employer of mathematicians and the world's largest
+purchaser of computer equipment. Such claims may be somewhat exaggerated, but
+beyond doubt the NSA -- and similar agencies in other countries -- have some
+excellent mathematicians, lots of powerful computers, sophisticated software,
+and the organisation and funding to apply them on a large scale. Details of
+the NSA budget are secret, but there are some published <a
+href="http://www.fas.org/irp/nsa/nsabudget.html">estimates</a>.</p>
+
+<p>Changes in the world's communications systems since WW II have provided
+these agencies with new targets. Cracking the codes used on an enemy's
+military or diplomatic communications has been common practice for centuries.
+Extensive use of radio in war made large-scale attacks such as Ultra
+possible. Modern communications make it possible to go far beyond that.
+Consider listening in on cell phones, or intercepting electronic mail, or
+tapping into the huge volumes of data on new media such as fiber optics or
+satellite links. None of these targets existed in 1950. All of them can be
+attacked today, and almost certainly are being attacked.</p>
+
+<p>The Ultra story was not made public until the 1970s. Much of the recent
+history of codes and code-breaking has not been made public, and some of it
+may never be. Two important books are:</p>
+<ul>
+  <li>Bamford's <a href="biblio.html#puzzle">The Puzzle Palace</a>, a history
+    of the NSA</li>
+  <li>Hager's <a href="http://www.fas.org/irp/eprint/sp/index.html">Secret
+    Power</a>, about the <a
+    href="http://sg.yahoo.com/government/intelligence/echelon_network/">Echelon</a>
+    system -- the US, UK, Canada, Australia and New Zealand co-operating to
+    monitor much of the world's communications.</li>
+</ul>
+
+<p>Note that these books cover only part of what is actually going on, and
+then only the activities of nations open and democratic enough that (some of)
+what they are doing can be discovered. A full picture, including:</p>
+<ul>
+  <li>actions of the English-speaking democracies not covered in those
+  books</li>
+  <li>actions of other more-or-less sane governments</li>
+  <li>the activities of various more-or-less insane governments</li>
+  <li>possibilities for unauthorized action by government employees</li>
+  <li>possible actions by large non-government organisations: corporations,
+    criminals, or conspiracies</li>
+</ul>
+
+<p>might be really frightening.</p>
+
+<h4><a name="recent">Recent history -- the crypto wars</a></h4>
+
+<p>Until quite recently, cryptography was primarily a concern of governments,
+especially of the military, of spies, and of diplomats. Much of it was
+extremely secret.</p>
+
+<p>In recent years, that has changed a great deal. With computers and
+networking becoming ubiquitous, cryptography is now important to almost
+everyone. Among the developments since the 1970s:</p>
+<ul>
+  <li>The US gov't established the Data Encryption Standard, <a
+    href="glossary.html#DES">DES</a>, a <a href="glossary.html#block">block
+    cipher</a> for cryptographic protection of unclassfied documents.</li>
+  <li>DES also became widely used in industry, especially regulated
+    industries such as banking.</li>
+  <li>Other nations produced their own standards, such as <a
+    href="glossary.html#GOST">GOST</a> in the Soviet Union.</li>
+  <li><a href="glossary.html#public">Public key</a> cryptography was invented
+    by Diffie and Hellman.</li>
+  <li>Academic conferences such as <a
+    href="http://www-cse.ucsd.edu/users/mihir/crypto2k.html">Crypto</a> and
+    <a
+    href="http://www.esat.kuleuven.ac.be/cosic/eurocrypt2000/">Eurocrypt</a>
+    began.</li>
+  <li>Several companies began offerring cryptographic products: <a
+    href="glossary.html#RSAco">RSA</a>, <a href="glossary.html#PGPI">PGP</a>,
+    the many vendors with <a href="glossary.html#PKI">PKI</a> products,
+  ...</li>
+  <li>Cryptography appeared in other products: operating systems, word
+    processors, ...</li>
+  <li>Network protocols based on crypto were developed:  <a
+    href="glossary.html#SSH">SSH</a>, <a href="glossary.html#SSL">SSL</a>, <a
+    href="glossary.html#IPsec">IPsec</a>, ...</li>
+  <li>Crytography came into widespread use to secure bank cards, terminals,
+    ...</li>
+  <li>The US government replaced <a href="glossary.html#DES">DES</a> with the
+    much stronger Advanced Encryption Standard, <a
+    href="glossary.html#AES">AES</a></li>
+</ul>
+
+<p>This has led to a complex ongoing battle between various mainly government
+groups wanting to control the spread of crypto and various others, notably
+the computer industry and the <a
+href="http://online.offshore.com.ai/security/">cypherpunk</a> crypto
+advocates, wanting to encourage widespread use.</p>
+
+<p>Steven Levy has written a fine history of much of this, called <a
+href="biblio.html#crypto">Crypto: How the Code rebels Beat the Government --
+Saving Privacy in the Digital Age</a>.</p>
+
+<p>The FreeS/WAN project is to a large extent an outgrowth of cypherpunk
+ideas. Our reasons for doing the project can be seen in these quotes from the
+<a
+href="http://www.eff.org/pub/Privacy/Crypto_misc/cypherpunk.manifesto">Cypherpunk
+Manifesto</a>:</p>
+
+<blockquote>
+  Privacy is necessary for an open society in the electronic age. ...
+
+  <p>We cannot expect governments, corporations, or other large, faceless
+  organizations to grant us privacy out of their beneficence.  It is to their
+  advantage to speak of us, and  we should expect that they will speak.
+  ...</p>
+
+  <p>We must defend our own privacy if we expect to have any. ...</p>
+
+  <p>Cypherpunks write code.  We know that someone has to write software to
+  defend privacy, and since we can't get privacy unless we all do, we're
+  going to write it. We publish our code so that our fellow Cypherpunks may
+  practice and play with it. Our code is free for all to use, worldwide.  We
+  don't much care if you don't approve of the software we write.  We know
+  that software can't be destroyed and that a widely dispersed system can't
+  be shut down.</p>
+
+  <p>Cypherpunks deplore regulations on cryptography, for encryption is
+  fundamentally a private act. ...</p>
+
+  <p>For privacy to be widespread it must be part of a social contract.
+  People must come and together deploy these systems for the common good.
+  ...</p>
+</blockquote>
+
+<p>To quote project leader John Gilmore:</p>
+
+<blockquote>
+  We are literally in a race between our ability to build and deploy
+  technology, and their ability to build and deploy laws and treaties.
+  Neither side is likely to back down or wise up until it has definitively
+  lost the race.</blockquote>
+
+<p>If FreeS/WAN reaches its goal of making <a
+href="intro.html#opp.intro">opportunistic encryption</a> widespread so that
+secure communication can become the default for a large part of the net, we
+will have struck a major blow.</p>
+
+<h3><a name="intro.poli">Politics</a></h3>
+
+<p>The political problem is that nearly all governments want to monitor their
+enemies' communications, and some want to monitor their citizens. They may be
+very interested in protecting some of their own communications, and often
+some types of business communication, but not in having everyone able to
+communicate securely. They therefore attempt to restrict availability of
+strong cryptography as much as possible.</p>
+
+<p>Things various governments have tried or are trying include:</p>
+<ul>
+  <li>Echelon, a monitor-the-world project of the US, UK, NZ, Australian and
+    Canadian <a href="glossary.html#SIGINT">signals intelligence</a>
+    agencies. See this <a
+    href="http://sg.yahoo.com/government/intelligence/echelon_network/">collection</a>
+    of links and this <a
+    href="http://www.zdnet.com/zdnn/stories/news/0,4586,2640682,00.html">story</a>
+    on the French Parliament's reaction.</li>
+  <li>Others governments may well have their own Echelon-like projects. To
+    quote the Dutch Minister of Defense, as reported in a German <a
+    href="http://www.heise.de/tp/english/inhalt/te/4729/1.html">magazine</a>:
+
+    <blockquote>
+      The government believes not only the governments associated with
+      Echelon are able to intercept communication systems, but that it is an
+      activity of the investigative authorities and intelligence services of
+      many countries with governments of different political
+    signature.</blockquote>
+    Even if they have nothing on the scale of Echelon, most intelligence
+    agencies and police forces certainly have some interception
+  capability.</li>
+  <li><a href="glossary.html#NSA">NSA</a> tapping of submarine communication
+    cables, described in <a
+    href="http://www.zdnet.com/zdnn/stories/news/0,4586,2764372,00.html">this
+    article</a></li>
+  <li>A proposal for international co-operation on <a
+    href="http://www.heise.de/tp/english/special/enfo/4306/1.html">Internet
+    surveillance</a>.</li>
+  <li>Alleged <a href="http://cryptome.org/nsa-sabotage.htm">sabotage</a> of
+    security products by the <a href="glossary.html#NSA">NSA</a> (the US
+    signals intelligence agency).</li>
+  <li>The German armed forces and some government departments will stop using
+    American software for fear of NSA "back doors", according to this <a
+    href="http://www.theregister.co.uk/content/4/17679.html">news
+  story</a>.</li>
+  <li>The British Regulation of Investigatory Powers bill. See this <a
+    href="http://www.fipr.org/rip/index.html">web page.</a> and perhaps this
+    <a
+    href="http://ars.userfriendly.org/cartoons/?id=20000806&amp;mode=classic">cartoon</a>.</li>
+  <li>A Russian <a
+    href="http://www.eff.org/pub/Privacy/Foreign_and_local/Russia/russian_crypto_ban_english.edict">ban</a>
+    on cryptography</li>
+  <li>Chinese <a
+    href="http://www.eff.org/pub/Misc/Publications/Declan_McCullagh/www/global/china">controls</a>
+    on net use.</li>
+  <li>The FBI's carnivore system for covert searches of email. See this <a
+    href="http://www.zdnet.com/zdnn/stories/news/0,4586,2601502,00.html">news
+    coverage</a> and this <a
+    href="http://www.crypto.com/papers/carnivore-risks.html">risk
+    assessment</a>. The government had an external review of some aspects of
+    this system done. See this <a
+    href="http://www.crypto.com/papers/carnivore_report_comments.html">analysis</a>
+    of that review. Possible defenses against Carnivore include:
+    <ul>
+      <li><a href="glossary.html#PGP">PGP</a> for end-to-end mail
+      encryption</li>
+      <li><a href="http://www.home.aone.net.au/qualcomm/">secure sendmail</a>
+        for server-to-server encryption</li>
+      <li>IPsec encryption on the underlying IP network</li>
+    </ul>
+  </li>
+  <li>export laws restricting strong cryptography as a munition. See <a
+    href="#exlaw">discussion</a> below.</li>
+  <li>various attempts to convince people that fundamentally flawed
+    cryptography, such as encryption with a <a href="#escrow">back door</a>
+    for government access to data or with <a href="#shortkeys">inadequate key
+    lengths</a>, was adequate for their needs.</li>
+</ul>
+
+<p>Of course governments are by no means the only threat to privacy and
+security on the net. Other threats include:</p>
+<ul>
+  <li>industrial espionage, as for example in this <a
+    href="http://www.zdnet.com/zdnn/stories/news/0,4586,2626931,00.html">news
+    story</a></li>
+  <li>attacks by organised criminals, as in this <a
+    href="http://www.sans.org/newlook/alerts/NTE-bank.htm">large-scale
+    attack</a></li>
+  <li>collection of personal data by various companies.
+    <ul>
+      <li>for example, consider the various corporate winners of Privacy
+        International's <a
+        href="http://www.privacyinternational.org/bigbrother/">Big Brother
+        Awards</a>.</li>
+      <li><a href="http://www.zeroknowledge.com">Zero Knowledge</a> sell
+        tools to defend against this</li>
+    </ul>
+  </li>
+  <li>individuals may also be a threat in a variety of ways and for a variety
+    of reasons</li>
+  <li>in particular, an individual with access to government or industry data
+    collections could do considerable damage using that data in unauthorized
+    ways.</li>
+</ul>
+
+<p>One <a
+href="http://www.zdnet.com/zdnn/stories/news/0,4586,2640674,00.html">study</a>
+enumerates threats and possible responses for small and medium businesses.
+VPNs are a key part of the suggested strategy.</p>
+
+<p>We consider privacy a human right. See the UN's <a href="http://www.un.org/Overview/rights.html">Universal
+Declaration of Human Rights</a>, article twelve:</p>
+
+<blockquote>
+  No one shall be subjected to arbitrary interference with his privacy,
+  family, home or correspondence, nor to attacks upon his honor and
+  reputation. Everyone has the right to the protection of the law against
+  such interference or attacks.</blockquote>
+
+<p>Our objective is to help make privacy possible on the Internet using
+cryptography strong enough not even those well-funded government agencies are
+likely to break it. If we can do that, the chances of anyone else breaking it
+are negliible.</p>
+
+<h3>Links</h3>
+
+<p>Many groups are working in different ways to defend privacy on the net and
+elsewhere. Please consider contributing to one or more of these groups:</p>
+<ul>
+  <li>the EFF's <a href="http://www.eff.org/crypto/">Privacy Now!</a>
+  campaign</li>
+  <li>the <a href="http://www.gilc.org">Global Internet Liberty
+  Campaign</a></li>
+  <li><a href="http://www.cpsr.org/program/privacy/privacy.html">Computer
+    Professionals for Social Responsibility</a></li>
+</ul>
+
+<p>For more on these issues see:</p>
+<ul>
+  <li>Steven Levy (Newsweek's chief technology writer and author of the
+    classic "Hackers") new book <a href="biblio.html#crypto">Crypto: How the
+    Code Rebels Beat the Government--Saving Privacy in the Digital
+  Age</a></li>
+  <li>Simson Garfinkel (Boston Globe columnist and author of books on <a
+    href="biblio.html#PGP">PGP</a> and <a href="biblio.html#practical">Unix
+    Security</a>) book <a href="biblio.html#Garfinkel">Database Nation: the
+    death of privacy in the 21st century</a></li>
+</ul>
+
+<p>There are several collections of <a href="web.html#quotes">crypto
+quotes</a> on the net.</p>
+
+<p>See also the <a href="biblio.html">bibliography</a> and our list of <a
+href="web.html#policy">web references</a> on cryptography law and policy.</p>
+
+<h3>Outline of this section</h3>
+
+<p>The remainder of this section includes two pieces of writing by our
+project leader</p>
+<ul>
+  <li>his <a href="#gilmore">rationale</a> for starting this</li>
+  <li>another <a href="#policestate">discussion</a> of project goals</li>
+</ul>
+
+<p>and discussions of:</p>
+<ul>
+  <li><a href="#desnotsecure">why we do not use DES</a></li>
+  <li><a href="#exlaw">cryptography export laws</a></li>
+  <li>why <a href="#escrow">government access to keys</a> is not a good
+  idea</li>
+  <li>the myth that <a href="#shortkeys">short keys</a> are adequate for some
+    security requirements</li>
+</ul>
+
+<p>and a section on <a href="#press">press coverage of FreeS/WAN</a>.</p>
+
+<h2><a name="leader">From our project leader</a></h2>
+
+<p>FreeS/WAN project founder John Gilmore wrote a web page about why we are
+doing this. The version below is slightly edited, to fit this format and to
+update some links. For a version without these edits, see his <a
+href="http://www.toad.com/gnu/">home page</a>.</p>
+
+<center>
+<h3><a name="gilmore">Swan: Securing the Internet against Wiretapping</a></h3>
+</center>
+
+<p>My project for 1996 was to <b>secure 5% of the Internet traffic against
+passive wiretapping</b>. It didn't happen in 1996, so I'm still working on it
+in 1997, 1998, and 1999! If we get 5% in 1999 or 2000, we can secure 20% the
+next year, against both active and passive attacks; and 80% the following
+year.  Soon the whole Internet will be private and secure. The project is
+called S/WAN or S/Wan or Swan for Secure Wide Area Network; since it's free
+software, we call it FreeSwan to distinguish it from various commercial
+implementations. <a href="http://www.rsa.com/rsa/SWAN/">RSA</a> came up with
+the term "S/WAN". Our main web site is at <a
+href="http://www.freeswan.org/">http://www.freeswan.org/</a>. Want to
+help?</p>
+
+<p>The idea is to deploy PC-based boxes that will sit between your local area
+network and the Internet (near your firewall or router) which
+opportunistically encrypt your Internet packets.  Whenever you talk to a
+machine (like a Web site) that doesn't support encryption, your traffic goes
+out "in the clear" as usual.  Whenever you connect to a machine that does
+support this kind of encryption, this box automatically encrypts all your
+packets, and decrypts the ones that come in.  In effect, each packet gets put
+into an "envelope" on one side of the net, and removed from the envelope when
+it reaches its destination.  This works for all kinds of Internet traffic,
+including Web access, Telnet, FTP, email, IRC, Usenet, etc.</p>
+
+<p>The encryption boxes are standard PC's that use freely available Linux
+software that you can download over the Internet or install from a cheap
+CDROM.</p>
+
+<p>This wasn't just my idea; lots of people have been working on it for
+years. The encryption protocols for these boxes are called <a
+href="glossary.html#IPsec">IPSEC (IP Security)</a>. They have been developed
+by the <a
+href="http://www.ietf.cnri.reston.va.us/html.charters/ipsec-charter.html">IP
+Security Working Group</a> of the <a href="http://www.ietf.org/">Internet
+Engineering Task Force</a>, and will be a standard part of the next major
+version of the Internet protocols (<a
+href="http://playground.sun.com/pub/ipng/html/ipng-main.html">IPv6</a>). For
+today's (IP version 4) Internet, they are an option.</p>
+
+<p>The <a href="http://www.iab.org/iab">Internet Architecture Board</a> and
+<a href="http://www.ietf.org/">Internet Engineering Steering Group</a> have
+taken a <a href="iab-iesg.stmt">strong stand</a> that the Internet should use
+powerful encryption to provide security and privacy.  I think these protocols
+are the best chance to do that, because they can be deployed very easily,
+without changing your hardware or software or retraining your users. They
+offer the best security we know how to build, using the Triple-DES, RSA, and
+Diffie-Hellman algorithms.</p>
+
+<p>This "opportunistic encryption box" offers the "fax effect".  As each
+person installs one for their own use, it becomes more valuable for their
+neighbors to install one too, because there's one more person to use it with.
+The software automatically notices each newly installed box, and doesn't
+require a network administrator to reconfigure it.  Instead of "virtual
+private networks" we have a "REAL private network"; we add privacy to the
+real network instead of layering a manually-maintained virtual network on top
+of an insecure Internet.</p>
+
+<h4>Deployment of IPSEC</h4>
+
+<p>The US government would like to control the deployment of IP Security with
+its <a href="#exlaw">crypto export laws</a>. This isn't a problem for my
+effort, because the cryptographic work is happening outside the United
+States. A foreign philanthropist, and others, have donated the resources
+required to add these protocols to the Linux operating system. <a
+href="http://www.linux.org/">Linux</a> is a complete, freely available
+operating system for IBM PC's and several kinds of workstation, which is
+compatible with Unix.  It was written by Linus Torvalds, and is still
+maintained by a talented team of expert programmers working all over the
+world and coordinating over the Internet.  Linux is distributed under the <a
+href="glossary.html#GPL">GNU Public License</a>, which gives everyone the
+right to copy it, improve it, give it to their friends, sell it commercially,
+or do just about anything else with it, without paying anyone for the
+privilege.</p>
+
+<p>Organizations that want to secure their network will be able to put two
+Ethernet cards into an IBM PC, install Linux on it from a $30 CDROM or by
+downloading it over the net, and plug it in between their Ethernet and their
+Internet link or firewall. That's all they'll have to do to encrypt their
+Internet traffic everywhere outside their own local area network.</p>
+
+<p>Travelers will be able to run Linux on their laptops, to secure their
+connection back to their home network (and to everywhere else that they
+connect to, such as customer sites). Anyone who runs Linux on a standalone PC
+will also be able to secure their network connections, without changing their
+application software or how they operate their computer from day to day.</p>
+
+<p>There will also be numerous commercially available firewalls that use this
+technology. <a href="http://www.rsa.com/">RSA Data Security</a> is
+coordinating the <a href="http://www.rsa.com/rsa/SWAN">S/Wan (Secure Wide
+Area Network)</a> project among more than a dozen vendors who use these
+protocols. There's a <a
+href="http://www.rsa.com/rsa/SWAN/swan_test.htm">compatability chart</a> that
+shows which vendors have tested their boxes against which other vendors to
+guarantee interoperatility.</p>
+
+<p>Eventually it will also move into the operating systems and networking
+protocol stacks of major vendors.  This will probably take longer, because
+those vendors will have to figure out what they want to do about the export
+controls.</p>
+
+<h4>Current status</h4>
+
+<p>My initial goal of securing 5% of the net by Christmas '96 was not met. It
+was an ambitious goal, and inspired me and others to work hard, but was
+ultimately too ambitious.  The protocols were in an early stage of
+development, and needed a lot more protocol design before they could be
+implemented.  As of April 1999, we have released version 1.0 of the software
+(<a
+href="ftp://ftp.xs4all.nl/freeswan/freeswan-1.0.tar.gz">freeswan-1.0.tar.gz</a>),
+which is suitable for setting up Virtual Private Networks using shared
+secrets for authentication.  It does not yet do opportunistic encryption, or
+use DNSSEC for authentication; those features are coming in a future
+release.</p>
+<dl>
+  <dt>Protocols</dt>
+    <dd>The low-level encrypted packet formats are defined.  The system for
+      publishing keys and providing secure domain name service is defined.
+      The IP Security working group has settled on an NSA-sponsored protocol
+      for key agreement (called ISAKMP/Oakley), but it is still being worked
+      on, as the protocol and its documentation is too complex and
+      incomplete. There are prototype implementations of ISAKMP.  The
+      protocol is not yet defined to enable opportunistic encryption or the
+      use of DNSSEC keys.</dd>
+  <dt>Linux Implementation</dt>
+    <dd>The Linux implementation has reached its first major release and is
+      ready for production use in manually-configured networks, using Linux
+      kernel version 2.0.36.</dd>
+  <dt>Domain Name System Security</dt>
+    <dd>There is now a release of BIND 8.2 that includes most DNS Security
+      features.
+      <p>The first prototype implementation of Domain Name System Security
+      was funded by <a href="glossary.html#DARPA">DARPA</a> as part of their
+      <a href="http://www.darpa.mil/ito/research/is/index.html">Information
+      Survivability program</a>. <a href="http://www.tis.com">Trusted
+      Information Systems</a> wrote a modified version of <a
+      href="http://www.isc.org/bind.html">BIND</a>, the widely-used Berkeley
+      implementation of the Domain Name System.</p>
+      <p>TIS, ISC, and I merged the prototype into the standard version of
+      BIND. The first production version that supports KEY and SIG records is
+      <b>bind-4.9.5</b>. This or any later version of BIND will do for
+      publishing keys.  It is available from the <a
+      href="http://www.isc.org/bind.html">Internet Software Consortium</a>.
+      This version of BIND is not export-controlled since it does not contain
+      any cryptography.  Later releases starting with BIND 8.2 include
+      cryptography for authenticating DNS records, which is also exportable.
+      Better documentation is needed.</p>
+    </dd>
+</dl>
+
+<h4>Why?</h4>
+
+<p>Because I can.  I have made enough money from several successful startup
+companies, that for a while I don't have to work to support myself. I spend
+my energies and money creating the kind of world that I'd like to live in and
+that I'd like my (future) kids to live in. Keeping and improving on the civil
+rights we have in the United States, as we move more of our lives into
+cyberspace, is a particular goal of mine.</p>
+
+<h4>What You Can Do</h4>
+<dl>
+  <dt>Install the latest BIND at your site.</dt>
+    <dd>You won't be able to publish any keys for your domain, until you have
+      upgraded your copy of BIND.  The thing you really need from it is the
+      new version of <i>named</i>, the Name Daemon, which knows about the new
+      KEY and SIG record types.  So, download it from the <a
+      href="http://www.isc.org/bind.html">Internet Software Consortium </a>
+      and install it on your name server machine (or get your system
+      administrator, or Internet Service Provider, to install it).  Both your
+      primary DNS site and all of your secondary DNS sites will need the new
+      release before you will be able to publish your keys.  You can tell
+      which sites this is by running the Unix command "dig MYDOMAIN ns" and
+      seeing which sites are mentioned in your NS (name server) records.</dd>
+  <dt>Set up a Linux system and run a 2.0.x kernel on it</dt>
+    <dd>Get a machine running Linux (say the 5.2 release from <a
+      href="http://www.redhat.com">Red Hat</a>). Give the machine two
+      Ethernet cards.</dd>
+  <dt>Install the Linux IPSEC (Freeswan) software</dt>
+    <dd>If you're an experienced sysadmin or Linux hacker, install the
+      freeswan-1.0 release, or any later release or snapshot. These releases
+      do NOT provide automated "opportunistic" operation; they must be
+      manually configured for each site you wish to encrypt with.</dd>
+  <dt>Get on the linux-ipsec mailing list</dt>
+    <dd>The discussion forum for people working on the project, and testing
+      the code and documentation, is: linux-ipsec@clinet.fi. To join this
+      mailing list, send email to <a
+      href="mailto:linux-ipsec-REQUEST@clinet.fi">linux-ipsec-REQUEST@clinet.fi</a>
+      containing a line of text that says "subscribe linux-ipsec". (You can
+      later get off the mailing list the same way -- just send "unsubscribe
+      linux-ipsec").</dd>
+
+  <p></p>
+  <dt>Check back at this web page every once in a while</dt>
+    <dd>I update this page periodically, and there may be new information in
+      it that you haven't seen.  My intent is to send email to the mailing
+      list when I update the page in any significant way, so subscribing to
+      the list is an alternative.</dd>
+</dl>
+
+<p>Would you like to help?  I can use people who are willing to write
+documentation, install early releases for testing, write cryptographic code
+outside the United States, sell pre-packaged software or systems including
+this technology, and teach classes for network administrators who want to
+install this technology. To offer to help, send me email at gnu@toad.com.
+Tell me what country you live in and what your citizenship is (it matters due
+to the export control laws; personally I don't care).  Include a copy of your
+resume and the URL of your home page.  Describe what you'd like to do for the
+project, and what you're uniquely qualified for.  Mention what other
+volunteer projects you've been involved in (and how they worked out). Helping
+out will require that you be able to commit to doing particular things, meet
+your commitments, and be responsive by email.  Volunteer projects just don't
+work without those things.</p>
+
+<h4>Related projects</h4>
+<dl>
+  <dt>IPSEC for NetBSD</dt>
+    <dd>This prototype implementation of the IP Security protocols is for
+      another free operating system. <a
+      href="ftp://ftp.funet.fi/pub/unix/security/net/ip/BSDipsec.tar.gz">Download
+      BSDipsec.tar.gz</a>.</dd>
+  <dt>IPSEC for <a href="http://www.openbsd.org">OpenBSD</a></dt>
+    <dd>This prototype implementation of the IP Security protocols is for yet
+      another free operating system.  It is directly integrated into the OS
+      release, since the OS is maintained in Canada, which has freedom of
+      speech in software.</dd>
+</dl>
+
+<h3><a name="policestate">Stopping wholesale monitoring</a></h3>
+
+<p>From a message project leader John Gilmore posted to the mailing list:</p>
+<pre>John Denker wrote:
+
+&gt; Indeed there are several ways in which the documentation overstates the 
+&gt; scope of what this project does -- starting with the name 
+&gt; FreeS/WAN.  There's a big difference between having an encrypted IP tunnel 
+&gt; versus having a Secure Wide-Area Network.  This software does a fine job of 
+&gt; the former, which is necessary but not sufficient for the latter.
+
+The goal of the project is to make it very hard to tap your wide area
+communications.  The current system provides very good protection
+against passive attacks (wiretapping and those big antenna farms).
+Active attacks, which involve the intruder sending packets to your
+system (like packets that break into sendmail and give them a root
+shell :-) are much harder to guard against.  Active attacks that
+involve sending people (breaking into your house and replacing parts
+of your computer with ones that transmit what you're doing) are also
+much harder to guard against.  Though we are putting effort into
+protecting against active attacks, it's a much bigger job than merely
+providing strong encryption.  It involves general computer security,
+and general physical security, which are two very expensive problems
+for even a site to solve, let alone to build into a whole society.
+
+The societal benefit of building an infrastructure that protects
+well against passive attacks is that it makes it much harder to do
+undetected bulk monitoring of the population.  It's a defense against
+police-states, not against policemen.
+
+Policemen can put in the effort required to actively attack sites that
+they have strong suspicions about.  But police states won't be able to
+build systems that automatically monitor everyone's communications.
+Either they will be able to monitor only a small subset of the
+populace (by targeting those who screwed up their passive security),
+or their monitoring activities will be detectable by those monitored
+(active attacks leave packet traces or footprints), which can then be
+addressed through the press and through political means if they become
+too widespread.
+
+FreeS/WAN does not protect very well against traffic analysis, which
+is a kind of widespread police-state style monitoring that still
+reveals significant information (who's talking to who) without
+revealing the contents of what was said.  Defenses against traffic
+analysis are an open research problem.  Zero Knowledge Systems is
+actively deploying a system designed to thwart it, designed by Ian
+Goldberg.  The jury is out on whether it actually works; a lot more
+experience with it will be needed.</pre>
+
+<p>Notes on things mentioned in that message:</p>
+<ul>
+  <li>Denker is a co-author of a <a href="intro.html#applied">paper</a> on a
+    large FreeS/WAN application.</li>
+  <li>Information on Zero Knowledge is on their <a
+    href="http://www.zks.net/">web site</a>. Their Freedom product, designed
+    to provide untracable pseudonyms for use on the net, is no longer
+    marketed.</li>
+  <li>Another section of our documentation discusses ways to <a
+    href="ipsec.html#traffic.resist">resist traffic analysis</a>.</li>
+</ul>
+
+<h2><a name="weak">Government promotion of weak crypto</a></h2>
+
+<p>Various groups, especially governments and especially the US government,
+have a long history of advocating various forms of bogus security.</p>
+
+<p>We regard bogus security as extremely dangerous. If users are deceived
+into relying on bogus security, then they may be exposed to large risks. They
+would be better off having no security and knowing it. At least then they
+would be careful about what they said.</p>
+
+<p><strong>Avoiding bogus security is a key design criterion for everything
+we do in FreeS/WAN</strong>. The most conspicuous example is our refusal to
+support <a href="#desnotsecure">single DES</a>. Other IPsec "features" which
+we do not implement are discussed in our <a
+href="compat.html#dropped">compatibility</a> document.</p>
+
+<h3><a name="escrow">Escrowed encryption</a></h3>
+
+<p>Various governments have made persistent attempts to encourage or mandate
+"escrowed encrytion", also called "key recovery", or GAK for "government
+access to keys". The idea is that cryptographic keys be held by some third
+party and turned over to law enforcement or security agencies under some
+conditions.</p>
+<pre>  Mary had a little key - she kept it in escrow,
+  and every thing that Mary said,
+  the feds were sure to know.</pre>
+
+<p>A <a href="web.html#quotes">crypto quotes</a> page attributes this to <a
+href="http://www.scramdisk.clara.net/">Sam Simpson</a>.</p>
+
+<p>There is an excellent paper available on <a
+href="http://www.cdt.org/crypto/risks98/">Risks of Escrowed Encryption</a>,
+from a group of cryptographic luminaries which included our project
+leader.</p>
+
+<p>Like any unnecessary complication, GAK tends to weaken security of any
+design it infects. For example:</p>
+<ul>
+  <li>Matt Blaze found a fatal flaw in the US government's Clipper chip
+    shortly after design information became public. See his paper "Protocol
+    Failure in the Escrowed Encryption Standard" on his <a
+    href="http://www.crypto.com/papers/">papers</a> page.</li>
+  <li>a rather <a href="http://www.pgp.com/other/advisories/adk.asp">nasty
+    bug</a> was found in the "additional decryption keys" "feature" of some
+    releases of <a href="glossary.html#PGP">PGP</a></li>
+</ul>
+
+<p>FreeS/WAN does not support escrowed encryption, and never will.</p>
+
+<h3><a name="shortkeys">Limited key lengths</a></h3>
+
+<p>Various governments, and some vendors, have also made persistent attempts
+to convince people that:</p>
+<ul>
+  <li>weak systems are sufficient for some data</li>
+  <li>strong cryptography should be reserved for cases where the extra
+    overheads are justified</li>
+</ul>
+
+<p><strong>This is utter nonsense</strong>.</p>
+
+<p>Weak systems touted include:</p>
+<ul>
+  <li>the ludicrously weak (deliberately crippled) 40-bit ciphers that until
+    recently were all various <a href="#exlaw">export laws</a> allowed</li>
+  <li>56-bit single DES, discussed <a href="#desnotsecure">below</a></li>
+  <li>64-bit symmetric ciphers and 512-bit RSA, the maximums for unrestricted
+    export under various current laws</li>
+</ul>
+
+<p>The notion that choice of ciphers or keysize should be determined by a
+trade-off between security requirements and overheads is pure bafflegab.</p>
+<ul>
+  <li>For most <a href="glossary.html#symmetric">symmetric ciphers</a>, it is
+    simply a lie. Any block cipher has some natural maximum keysize inherent
+    in the design -- 128 bits for <a href="glossary.html#IDEA">IDEA</a> or <a
+    href="glossary.html#CAST128">CAST-128</a>, 256 for Serpent or Twofish,
+    448 for <a href="glossary.html#Blowfish">Blowfish</a> and 2048 for <a
+    href="glossary.html#RC4">RC4</a>. Using a key size smaller than that
+    limit gives <em>exactly zero </em>savings in overhead. The crippled
+    40-bit or 64-bit version of the cipher provides <em>no advantage
+    whatsoever</em>.</li>
+  <li><a href="glossary.html#AES">AES</a> uses 10 rounds with 128-bit keys,
+    12 rounds for 192-bit and 14 rounds for 256-bit, so there actually is a
+    small difference in overhead, but not enough to matter in most
+    applications.</li>
+  <li>For <a href="glossary.html#3DES">triple DES</a> there is a grain of
+    truth in the argument. 3DES is indeed three times slower than single DES.
+    However, the solution is not to use the insecure single DES, but to pick
+    a faster secure cipher. <a href="glossary.html#CAST128">CAST-128</a>, <a
+    href="glossary.html#Blowfish">Blowfish</a> and the <a
+    href="glossary.html#AES">AES candidate</a> ciphers are are all
+    considerably faster in software than DES (let alone 3DES!), and
+    apparently secure.</li>
+  <li>For <a href="glossary.html#public">public key</a> techniques, there are
+    extra overheads for larger keys, but they generally do not affect overall
+    performance significantly. Practical public key applications are usually
+    <a href="glossary.html#hybrid">hybrid</a> systems in which the bulk of
+    the work is done by a symmetric cipher. The effect of increasing the cost
+    of the public key operations is typically negligible because the public
+    key operations use only a tiny fraction of total resources.
+    <p>For example, suppose public key operations use use 1% of the time in a
+    hybrid system and you triple the cost of public key operations. The cost
+    of symmetric cipher operations is unchanged at 99% of the original total
+    cost, so the overall effect is a jump from 99 + 1 = 100 to 99 + 3 = 102,
+    a 2% rise in system cost.</p>
+  </li>
+</ul>
+
+<p>In short, <strong>there has never been any technical reason to use
+inadequate ciphers</strong>. The only reason there has ever been for anyone
+to use such ciphers is that government agencies want weak ciphers used so
+that they can crack them. The alleged savings are simply propaganda.</p>
+<pre>   Mary had a little key (It's all she could export),
+   and all the email that she sent was opened at the Fort.</pre>
+
+<p>A <a href="web.html#quotes">crypto quotes</a> page attributes this to <a
+href="http://theory.lcs.mit.edu:80/~rivest/">Ron Rivest</a>. NSA headquarters
+is at Fort Meade, Maryland.</p>
+
+<p>Our policy in FreeS/WAN is to use only cryptographic components with
+adequate keylength and no known weaknesses.</p>
+<ul>
+  <li>We do not implement single DES because it is clearly <a
+    href="#desnotsecure">insecure</a>, so implemeting it would violate our
+    policy of avoiding bogus security. Our default cipher is <a
+    href="glossary.html#3DES">3DES</a></li>
+  <li>Similarly, we do not implement the 768-bit Group 1 for <a
+    href="glossary.html#DH">Diffie-Hellman</a> key negotiation. We provide
+    only the 1024-bit Group 2 and 1536-bit Group 5.</li>
+</ul>
+
+<p>Detailed discussion of which IPsec features we implement or omit is in out
+<a href="compat.html">compatibility document</a>.</p>
+
+<p>These decisions imply that we cannot fully conform to the IPsec RFCs,
+since those have DES as the only required cipher and Group 1 as the only
+required DH group. (In our view, the standards were subverted into offerring
+bogus security.) Fortunately, we can still interoperate with most other IPsec
+implementations since nearly all implementers provide at least 3DES and Group
+2 as well.</p>
+
+<p>We hope that eventually the RFCs will catch up with our (and others')
+current practice and reject dubious components. Some of our team and a number
+of others are working on this in <a href="glossary.html#IETF">IETF</a>
+working groups.</p>
+
+<h4>Some real trade-offs</h4>
+
+<p>Of course, making systems secure does involve costs, and trade-offs can be
+made between cost and security. However, the real trade-offs have nothing to
+do with using weaker ciphers.</p>
+
+<p>There can be substantial hardware and software costs. There are often
+substantial training costs, both to train administrators and to increase user
+awareness of security issues and procedures. There are almost always
+substantial staff or contracting costs.</p>
+
+<p>Security takes staff time for planning, implementation, testing and
+auditing. Some of the issues are subtle; you need good (hence often
+expensive) people for this. You also need people to monitor your systems and
+respond to problems. The best safe ever built is insecure if an attacker can
+work on it for days without anyone noticing. Any computer is insecure if the
+administrator is "too busy" to check the logs.</p>
+
+<p>Moreover, someone in your organisation (or on contract to it) needs to
+spend considerable time keeping up with new developments. EvilDoers
+<em>will</em> know about new attacks shortly after they are found. You need
+to know about them before your systems are attacked. If your vendor provides
+a patch, you need to apply it. If the vendor does nothing, you need to
+complain or start looking for another vendor.</p>
+
+<p>For a fairly awful example, see this <a
+href="http://www.sans.org/newlook/alerts/NTE-bank.htm">report</a>. In that
+case over a million credit card numbers were taken from e-commerce sites,
+using security flaws in Windows NT servers. Microsoft had long since released
+patches for most or all of the flaws, but the site administrators had not
+applied them.</p>
+
+<p>At an absolute minimum, you must do something about such issues
+<em>before</em> an exploitation tool is posted to the net for downloading by
+dozens of "script kiddies". Such a tool might appear at any time from the
+announcement of the security hole to several months later. Once it appears,
+anyone with a browser and an attitude can break any system whose
+administrators have done nothing about the flaw.</p>
+
+<p>Compared to those costs, cipher overheads are an insignificant factor in
+the cost of security.</p>
+
+<p>The only thing using a weak cipher can do for you is to cause all your
+other investment to be wasted.</p>
+
+<h2><a name="exlaw">Cryptography Export Laws</a></h2>
+
+<p>Many nations restrict the export of cryptography and some restrict its use
+by their citizens or others within their borders.</p>
+
+<h3><a name="USlaw">US Law</a></h3>
+
+<p>US laws, as currently interpreted by the US government, forbid export of
+most cryptographic software from the US in machine-readable form without
+government permission. In general, the restrictions apply even if the
+software is widely-disseminated or public-domain and even if it came from
+outside the US originally. Cryptography is legally a munition and export is
+tightly controlled under the <a href="glossary.html#EAR">EAR</a> Export
+Administration Regulations.</p>
+
+<p>If you are a US citizen, your brain is considered US territory no matter
+where it is physically located at the moment. The US believes that its laws
+apply to its citizens everywhere, not just within the US. Providing technical
+assistance or advice to foreign "munitions" projects is illegal. The US
+government has very little sense of humor about this issue and does not
+consider good intentions to be sufficient excuse. Beware.</p>
+
+<p>The <a href="http://www.bxa.doc.gov/Encryption/">official website</a> for
+these regulations is run by the Commerce Department's Bureau of Export
+Administration (BXA).</p>
+
+<p>The <a href="http://www.eff.org/bernstein/">Bernstein case</a> challenges
+the export restrictions on Constitutional grounds. Code is speech so
+restrictions on export of code violate the First Amendment's free speech
+provisions. This argument has succeeded in two levels of court so far. It is
+quite likely to go on to the Supreme Court.</p>
+
+<p>The regulations were changed substantially in January 2000, apparently as
+a government attempt to get off the hook in the Bernstein case. It is now
+legal to export public domain source code for encryption, provided you notify
+the <a href="glossary.html#BXA">BXA</a>.</p>
+
+<p>There are, however, still restrictions in force.
+ Moreover, the regulations can still be changed again whenever the government
+chooses to do so. Short of a Supreme Court ruling (in the Berstein case or
+another) that overturns the regulations completely, the problem of export
+regulation is not likely to go away in the forseeable future.</p>
+
+<h4><a name="UScontrib">US contributions to FreeS/WAN</a></h4>
+
+<p>The FreeS/WAN project <strong>cannot accept software contributions, <em>
+not even small bug fixes</em>, from US citizens or residents</strong>. We
+want it to be absolutely clear that our distribution is not subject to US
+export law. Any contribution from an American might open that question to a
+debate we'd prefer to avoid. It might also put the contributor at serious
+legal risk.</p>
+
+<p>Of course Americans can still make valuable contributions (many already
+have) by reporting bugs, or otherwise contributing to discussions, on the
+project <a href="mail.html">mailing list</a>. Since the list is public, this
+is clearly constitutionally protected free speech.</p>
+
+<p>Note, however, that the export laws restrict Americans from providing
+technical assistance to foreign "munitions" projects. The government might
+claim that private discussions or correspondence with FreeS/WAN developers
+were covered by this. It is not clear what the courts would do with such a
+claim, so we strongly encourage Americans to use the list rather than risk
+the complications.</p>
+
+<h3><a name="wrong">What's wrong with restrictions on cryptography</a></h3>
+
+<p>Some quotes from prominent cryptography experts:</p>
+
+<blockquote>
+  The real aim of current policy is to ensure the continued effectiveness of
+  US information warfare assets against individuals, businesses and
+  governments in Europe and elsewhere.<br>
+  <a href="http://www.cl.cam.ac.uk/users/rja14"> Ross Anderson, Cambridge
+  University</a></blockquote>
+
+<blockquote>
+  If the government were honest about its motives, then the debate about
+  crypto export policy would have ended years ago.<br>
+  <a href="http://www.counterpane.com"> Bruce Schneier, Counterpane
+  Systems</a></blockquote>
+
+<blockquote>
+  The NSA regularly lies to people who ask it for advice on export control.
+  They have no reason not to; accomplishing their goal by any legal means is
+  fine by them. Lying by government employees is legal.<br>
+  John Gilmore.</blockquote>
+
+<p>The Internet Architecture Board (IAB) and the Internet Engineering
+Steering Group (IESG) made a <a href="iab-iesg.stmt">strong statement</a> in
+favour of worldwide access to strong cryptography. Essentially the same
+statement is in the appropriately numbered <a
+href="ftp://ftp.isi.edu/in-notes/rfc1984.txt">RFC 1984</a>. Two critical
+paragraphs are:</p>
+
+<blockquote>
+  ... various governments have actual or proposed policies on access to
+  cryptographic technology ...
+
+  <p>(a) ... export controls ...<br>
+  (b) ... short cryptographic keys ...<br>
+  (c) ... keys should be in the hands of the government or ...<br>
+  (d) prohibit the use of cryptology ...</p>
+
+  <p>We believe that such policies are against the interests of consumers and
+  the business community, are largely irrelevant to issues of military
+  security, and provide only a marginal or illusory benefit to law
+  enforcement agencies, ...</p>
+
+  <p>The IAB and IESG would like to encourage policies that allow ready
+  access to uniform strong cryptographic technology for all Internet users in
+  all countries.</p>
+</blockquote>
+
+<p>Our goal in the FreeS/WAN project is to build just such "strong
+cryptographic technology" and to distribute it "for all Internet users in all
+countries".</p>
+
+<p>More recently, the same two bodies (IESG and IAB) have issued <a
+href="ftp://ftp.isi.edu/in-notes/rfc2804.txt">RFC 2804</a> on why the IETF
+should not build wiretapping capabilities into protocols for the convenience
+of security or law enforcement agenicies. The abstract from that document
+is:</p>
+
+<blockquote>
+  The Internet Engineering Task Force (IETF) has been asked to take a
+  position on the inclusion into IETF standards-track documents of
+  functionality designed to facilitate wiretapping.
+
+  <p>This memo explains what the IETF thinks the question means, why its
+  answer is "no", and what that answer means.</p>
+</blockquote>
+A quote from the debate leading up to that RFC:
+
+<blockquote>
+  We should not be building surveillance technology into standards. Law
+  enforcement was not supposed to be easy. Where it is easy, it's called a
+  police state.<br>
+  Jeff Schiller of MIT, in a discussion of FBI demands for wiretap capability
+  on the net, as quoted by <a
+  href="http://www.wired.com/news/politics/0,1283,31895,00.html">Wired</a>.</blockquote>
+
+<p>The <a href="http://www.ietf.org/mailman/listinfo/raven">Raven</a> mailing
+list was set up for this IETF discussion.</p>
+
+<p>Our goal is to go beyond that RFC and prevent Internet wiretapping
+entirely.</p>
+
+<h3><a name="Wassenaar">The Wassenaar Arrangement</a></h3>
+
+<p>Restrictions on the export of cryptography are not just US policy, though
+some consider the US at least partly to blame for the policies of other
+nations in this area.</p>
+
+<p>A number of countries:</p>
+
+<p>Argentina, Australia, Austria, Belgium, Bulgaria, Canada, Czech Republic,
+Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Japan,
+Luxembourg, Netherlands, New Zealand, Norway, Poland, Portugal, Republic of
+Korea, Romania, Russian Federation, Slovak Republic, Spain, Sweden,
+Switzerland, Turkey, Ukraine, United Kingdom and United States</p>
+
+<p>have signed the Wassenaar Arrangement which restricts export of munitions
+and other tools of war. Cryptographic sofware is covered there.</p>
+
+<p>Wassenaar details are available from the <a
+href="http://www.wassenaar.org/"> Wassenaar Secretariat</a>, and elsewhere in
+a more readable <a href="http://www.fitug.de/news/wa/index.html"> HTML
+version</a>.</p>
+
+<p>For a critique see the <a href="http://www.gilc.org/crypto/wassenaar">
+GILC site</a>:</p>
+
+<blockquote>
+  The Global Internet Liberty Campaign (GILC) has begun a campaign calling
+  for the removal of cryptography controls from the Wassenaar Arrangement.
+
+  <p>The aim of the Wassenaar Arrangement is to prevent the build up of
+  military capabilities that threaten regional and international security and
+  stability . . .</p>
+
+  <p>There is no sound basis within the Wassenaar Arrangement for the
+  continuation of any export controls on cryptographic products.</p>
+</blockquote>
+
+<p>We agree entirely.</p>
+
+<p>An interesting analysis of Wassenaar can be found on the <a
+href="http://www.cyber-rights.org/crypto/wassenaar.htm">cyber-rights.org</a>
+site.</p>
+
+<h3><a name="status">Export status of Linux FreeS/WAN</a></h3>
+
+<p>We believe our software is entirely exempt from these controls since the
+Wassenaar <a
+href="http://www.wassenaar.org/list/GTN%20and%20GSN%20-%2099.pdf">General
+Software Note</a> says:</p>
+
+<blockquote>
+  The Lists do not control "software" which is either:
+  <ol>
+    <li>Generally available to the public by . . . retail . . . or</li>
+    <li>"In the public domain".</li>
+  </ol>
+</blockquote>
+
+<p>There is a note restricting some of this, but it is a sub-heading under
+point 1, so it appears not to apply to public domain software.</p>
+
+<p>Their glossary defines "In the public domain" as:</p>
+
+<blockquote>
+  . . . "technology" or "software" which has been made available without
+  restrictions upon its further dissemination.
+
+  <p>N.B. Copyright restrictions do not remove "technology" or "software"
+  from being "in the public domain".</p>
+</blockquote>
+
+<p>We therefore believe that software freely distributed under the <a
+href="glossary.html#GPL">GNU Public License</a>, such as Linux FreeS/WAN, is
+exempt from Wassenaar restrictions.</p>
+
+<p>Most of the development work is being done in Canada. Our understanding is
+that the Canadian government accepts this interpretation.</p>
+<ul>
+  <li>A web statement of <a
+    href="http://www.dfait-maeci.gc.ca/~eicb/notices/ser113-e.htm"> Canadian
+    policy</a> is available from the Department of Foreign Affairs and
+    International Trade.</li>
+  <li>Another document from that department states that <a
+    href="http://www.dfait-maeci.gc.ca/~eicb/export/gr1_e.htm">public domain
+    software</a> is exempt from the export controls.</li>
+  <li>A researcher's <a
+    href="http://insight.mcmaster.ca/org/efc/pages/doc/crypto-export.html">analysis</a>
+    of Canadian policy is also available.</li>
+</ul>
+
+<p>Recent copies of the freely modifiable and distributable source code exist
+in many countries. Citizens all over the world participate in its use and
+evolution, and guard its ongoing distribution. Even if Canadian policy were
+to change, the software would continue to evolve in countries which do not
+restrict exports, and would continue to be imported from there into unfree
+countries. "The Net culture treats censorship as damage, and routes around
+it."</p>
+
+<h3><a name="help">Help spread IPsec around</a></h3>
+
+<p>You can help. If you don't know of a Linux FreeS/WAN archive in your own
+country, please download it now to your personal machine, and consider making
+it publicly accessible if that doesn't violate your own laws. If you have the
+resources, consider going one step further and setting up a mirror site for
+the whole <a href="intro.html#munitions">munitions</a> Linux crypto software
+archive.</p>
+
+<p>If you make Linux CD-ROMs, please consider including this code, in a way
+that violates no laws (in a free country, or in a domestic-only CD
+product).</p>
+
+<p>Please send a note about any new archive mirror sites or CD distributions
+to linux-ipsec@clinet.fi so we can update the documentation.</p>
+
+<p>Lists of current <a href="intro.html#sites">mirror sites</a> and of <a
+href="intro.html#distwith">distributions</a> which include FreeS/WAN are in
+our introduction section.</p>
+
+<h2><a name="desnotsecure">DES is Not Secure</a></h2>
+
+<p>DES, the <strong>D</strong>ata <strong>E</strong>ncryption
+<strong>S</strong>tandard, can no longer be considered secure. While no major
+flaws in its innards are known, it is fundamentally inadequate because its
+<strong>56-bit key is too short</strong>. It is vulnerable to <a
+href="glossary.html#brute">brute-force search</a> of the whole key space,
+either by large collections of general-purpose machines or even more quickly
+by specialized hardware. Of course this also applies to <strong>any other
+cipher with only a 56-bit key</strong>. The only reason anyone could have for
+using a 56 or 64-bit key is to comply with various <a
+href="exportlaw.html">export laws</a> intended to ensure the use of breakable
+ciphers.</p>
+
+<p>Non-government cryptologists have been saying DES's 56-bit key was too
+short for some time -- some of them were saying it in the 70's when DES
+became a standard -- but the US government has consistently ridiculed such
+suggestions.</p>
+
+<p>A group of well-known cryptographers looked at key lengths in a <a
+href="http://www.counterpane.com/keylength.html"> 1996 paper</a>. They
+suggested a <em>minimum</em> of 75 bits to consider an existing cipher secure
+and a <em>minimum of 90 bits for new ciphers</em>. More recent papers,
+covering both <a href="glossary.html#symmetric">symmetric</a> and <a
+href="glossary.html#public">public key</a> systems are at <a
+href="http://www.cryptosavvy.com/">cryptosavvy.com</a> and <a
+href="http://www.rsasecurity.com/rsalabs/bulletins/bulletin13.html">rsa.com</a>.
+For all algorithms, the minimum keylengths recommended in such papers are
+significantly longer than the maximums allowed by various export laws.</p>
+
+<p>In a <a
+href="http://www.privacy.nb.ca/cryptography/archives/cryptography/html/1998-09/0095.html">1998
+ruling</a>, a German court described DES as "out-of-date and not safe enough"
+and held a bank liable for using it.</p>
+
+<h3><a name="deshware">Dedicated hardware breaks DES in a few days</a></h3>
+
+<p>The question of DES security has now been settled once and for all. In
+early 1998, the <a href="http://www.eff.org/">Electronic Frontier
+Foundation</a> built a <a
+href="http://www.eff.org/descracker.html">DES-cracking machine</a>. It can
+find a DES key in an average of a few days' search. The details of all this,
+including complete code listings and complete plans for the machine, have
+been published in <a href="biblio.html#EFF"><cite>Cracking DES</cite></a>, by
+the Electronic Frontier Foundation.</p>
+
+<p>That machine cost just over $200,000 to design and build. "Moore's Law" is
+that machines get faster (or cheaper, for the same speed) by roughly a factor
+of two every 18 months. At that rate, their $200,000 in 1998 becomes $50,000
+in 2001.</p>
+
+<p>However, Moore's Law is not exact and the $50,000 estimate does not allow
+for the fact that a copy based on the published EFF design would cost far
+less than the original. We cannot say exactly what such a cracker would cost
+today, but it would likely be somewhere between $10,000 and $100,000.</p>
+
+<p>A large corporation could build one of these out of petty cash. The cost
+is low enough for a senior manager to hide it in a departmental budget and
+avoid having to announce or justify the project. Any government agency, from
+a major municipal police force up, could afford one. Or any other group with
+a respectable budget -- criminal organisations, political groups, labour
+unions, religious groups, ... Or any millionaire with an obsession or a
+grudge, or just strange taste in toys.</p>
+
+<p>One might wonder if a private security or detective agency would have one
+for rent. They wouldn't need many clients to pay off that investment.</p>
+
+<h3><a name="spooks">Spooks may break DES faster yet</a></h3>
+
+<p>As for the security and intelligence agencies of various nations, they may
+have had DES crackers for years, and theirs may be much faster. It is
+difficult to make most computer applications work well on parallel machines,
+or to design specialised hardware to accelerate them. Cipher-cracking is one
+of the very few exceptions. It is entirely straightforward to speed up
+cracking by just adding hardware. Within very broad limits, you can make it
+as fast as you like if you have the budget. The EFF's $200,000 machine breaks
+DES in a few days. An <a href="http://www.planepage.com/">aviation
+website</a> gives the cost of a B1 bomber as $200,000,000. Spending that
+much, an intelligence agency could break DES in an average time of <em>six
+and a half minutes</em>.</p>
+
+<p>That estimate assumes they use the EFF's 1998 technology and just spend
+more money. They may have an attack that is superior to brute force, they
+quite likely have better chip technology (Moore's law, a bigger budget, and
+whatever secret advances they may have made) and of course they may have
+spent the price of an aircraft carrier, not just one aircraft.</p>
+
+<p>In short, we have <em>no idea</em> how quickly these organisations can
+break DES. Unless they're spectacularly incompetent or horribly underfunded,
+they can certainly break it, but we cannot guess how quickly. Pick any time
+unit between days and milliseconds; none is entirely unbelievable. More to
+the point, none of them is  of any comfort if you don't want such
+organisations reading your communications.</p>
+
+<p>Note that this may be a concern even if nothing you do is a threat to
+anyone's national security. An intelligence agency might well consider it to
+be in their national interest for certain companies to do well. If you're
+competing against such companies in a world market and that agency can read
+your secrets, you have a serious problem.</p>
+
+<p>One might wonder about technology the former Soviet Union and its allies
+developed for cracking DES during the Cold War. They must have tried; the
+cipher was an American standard and widely used. Certainly those countries
+have some fine mathematicians, and those agencies had budget. How well did
+they succeed? Is their technology now for sale or rent?</p>
+
+<h3><a name="desnet">Networks break DES in a few weeks</a></h3>
+
+<p>Before the definitive EFF effort, DES had been cracked several times by
+people using many machines. See this <a
+href="http://www.distributed.net/pressroom/DESII-1-PR.html"> press
+release</a> for example.</p>
+
+<p>A major corporation, university, or government department could break DES
+by using spare cycles on their existing collection of computers, by
+dedicating a group of otherwise surplus machines to the problem, or by
+combining the two approaches. It might take them weeks or months, rather than
+the days required for the EFF machine, but they could do it.</p>
+
+<p>What about someone working alone, without the resources of a large
+organisation? For them, cracking DES will not be easy, but it may be
+possible. A few thousand dollars buys a lot of surplus workstations. A pile
+of such machines will certainly heat your garage nicely and might break DES
+in a few months or years. Or enroll at a university and use their machines.
+Or use an employer's machines. Or crack security somewhere and steal the
+resources to crack a DES key. Or write a virus that steals small amounts of
+resources on many machines. Or . . .</p>
+
+<p>None of these approaches are easy or break DES really quickly, but an
+attacker only needs to find one that is feasible and breaks DES quickly
+enough to be dangerous. How much would you care to bet that this will be
+impossible if the attacker is clever and determined? How valuable is your
+data? Are you authorised to risk it on a dubious bet?</p>
+
+<h3><a name="no_des">We disable DES</a></h3>
+
+<p>In short, it is now absolutely clear that <strong>DES is not
+secure</strong> against</p>
+<ul>
+  <li>any <strong>well-funded opponent</strong></li>
+  <li>any opponent (even a penniless one) with access (even stolen access) to
+    <strong>enough general purpose computers</strong></li>
+</ul>
+
+<p>That is why <strong>Linux FreeS/WAN disables all transforms which use
+plain DES</strong> for encryption.</p>
+
+<p>DES is in the source code, because we need DES to implement our default
+encryption transform, <a href="glossary.html#3DES">Triple DES</a>. <strong>We
+urge you not to use single DES</strong>. We do not provide any easy way to
+enable it in FreeS/WAN, and our policy is to provide no assistance to anyone
+wanting to do so.</p>
+
+<h3><a name="40joke">40-bits is laughably weak</a></h3>
+
+<p>The same is true, in spades, of ciphers -- DES or others -- crippled by
+40-bit keys, as many ciphers were required to be until recently under various
+<a href="#exlaw">export laws</a>. A brute force search of such a cipher's
+keyspace is 2<sup>16</sup> times faster than a similar search against DES.
+The EFF's machine can do a brute-force search of a 40-bit key space in
+<em>seconds</em>. One contest to crack a 40-bit cipher was won by a student
+<a href="http://catless.ncl.ac.uk/Risks/18.80.html#subj1"> using a few
+hundred idle machines at his university</a>. It took only three and half
+hours.</p>
+
+<p>We do not, and will not, implement any 40-bit cipher.</p>
+
+<h3><a name="altdes">Triple DES is almost certainly secure</a></h3>
+
+<p><a href="glossary.html#3DES">Triple DES</a>, usually abbreviated 3DES,
+applies DES three times, with three different keys. DES seems to be basically
+an excellent cipher design; it has withstood several decades of intensive
+analysis without any disastrous flaws being found. It's only major flaw is
+that the small keyspace allows brute force attacks to succeeed. Triple DES
+enlarges the key space to 168 bits, making brute-force search a ridiculous
+impossibility.</p>
+
+<p>3DES is currently the only block cipher implemented in FreeS/WAN. 3DES is,
+unfortunately, about 1/3 the speed of DES, but modern CPUs still do it at
+quite respectable speeds. Some <a href="glossary.html#benchmarks">speed
+measurements</a> for our code are available.</p>
+
+<h3><a name="aes.ipsec">AES in IPsec</a></h3>
+
+<p>The <a href="glossary.html#AES">AES</a> project has chosen a replacement
+for DES, a new standard cipher for use in non-classified US government work
+and in regulated industries such as banking. This cipher will almost
+certainly become widely used for many applications, including IPsec.</p>
+
+<p>The winner, announced in October 2000 after several years of analysis and
+discussion, was the <a
+href="http://www.esat.kuleuven.ac.be/~rijmen/rijndael/">Rijndael</a> cipher
+from two Belgian designers.</p>
+
+<p>It is almost certain that FreeS/WAN will add AES support. <a
+href="web.html#patch">AES patches</a> are already available.</p>
+
+<h2><a name="press">Press coverage of Linux FreeS/WAN:</a></h2>
+
+<h3>FreeS/WAN 1.0 press</h3>
+<ul>
+  <li><a
+    href="http://www.wired.com/news/news/technology/story/19136.html">Wired</a>
+    "Linux-Based Crypto Stops Snoops", James Glave April 15 1999</li>
+  <li><a
+    href="http://slashdot.org/articles/99/04/15/1851212.shtml">Slashdot</a></li>
+  <li><a href="http://dgl.com/itinfo/1999/it990415.html">DGL</a>, Damar Group
+    Limited; looking at FreeS/WAN from a perspective of business
+  computing</li>
+  <li><a href="http://linuxtoday.com/stories/5010.html">Linux Today</a></li>
+  <li><a href="http://www.tbtf.com/archive/1999-04-21.html#Tcep">TBTF</a>,
+    Tasty Bits from the Technology Front</li>
+  <li><a
+    href="http://www.salonmagazine.com/tech/log/1999/04/16/encryption/index.html">Salon
+    Magazine</a> "Free Encryption Takes a Big Step"</li>
+</ul>
+
+<h3><a name="release">Press release for version 1.0</a></h3>
+<pre>        Strong Internet Privacy Software Free for Linux Users Worldwide
+
+Toronto, ON, April 14, 1999 - 
+
+The Linux FreeS/WAN project today released free software to protect
+the privacy of Internet communications using strong encryption codes.
+FreeS/WAN automatically encrypts data as it crosses the Internet, to
+prevent unauthorized people from receiving or modifying it.  One
+ordinary PC per site runs this free software under Linux to become a
+secure gateway in a Virtual Private Network, without having to modify
+users' operating systems or application software.  The project built
+and released the software outside the United States, avoiding US
+government regulations which prohibit good privacy protection.
+FreeS/WAN version 1.0 is available immediately for downloading at
+http://www.xs4all.nl/~freeswan/.
+
+"Today's FreeS/WAN release allows network administrators to build
+excellent secure gateways out of old PCs at no cost, or using a cheap
+new PC," said John Gilmore, the entrepreneur who instigated the
+project in 1996.  "They can build operational experience with strong
+network encryption and protect their users' most important
+communications worldwide."
+
+"The software was written outside the United States, and we do not
+accept contributions from US citizens or residents, so that it can be
+freely published for use in every country," said Henry Spencer, who
+built the release in Toronto, Canada.  "Similar products based in the
+US require hard-to-get government export licenses before they can be
+provided to non-US users, and can never be simply published on a Web
+site.  Our product is freely available worldwide for immediate
+downloading, at no cost."
+
+FreeS/WAN provides privacy against both quiet eavesdropping (such as
+"packet sniffing") and active attempts to compromise communications
+(such as impersonating participating computers).  Secure "tunnels" carry
+information safely across the Internet between locations such as a
+company's main office, distant sales offices, and roaming laptops.  This
+protects the privacy and integrity of all information sent among those
+locations, including sensitive intra-company email, financial transactions
+such as mergers and acquisitions, business negotiations, personal medical
+records, privileged correspondence with lawyers, and information about
+crimes or civil rights violations.  The software will be particularly
+useful to frequent wiretapping targets such as private companies competing
+with government-owned companies, civil rights groups and lawyers,
+opposition political parties, and dissidents. 
+
+FreeS/WAN provides privacy for Internet packets using the proposed
+standard Internet Protocol Security (IPSEC) protocols.  FreeS/WAN
+negotiates strong keys using Diffie-Hellman key agreement with 1024-bit
+keys, and encrypts each packet with 168-bit Triple-DES (3DES).  A modern
+$500 PC can set up a tunnel in less than a second, and can encrypt
+6 megabits of packets per second, easily handling the whole available
+bandwidth at the vast majority of Internet sites.  In preliminary testing,
+FreeS/WAN interoperated with 3DES IPSEC products from OpenBSD, PGP, SSH,
+Cisco, Raptor, and Xedia.  Since FreeS/WAN is distributed as source code,
+its innards are open to review by outside experts and sophisticated users,
+reducing the chance of undetected bugs or hidden security compromises.
+
+The software has been in development for several years.  It has been
+funded by several philanthropists interested in increased privacy on
+the Internet, including John Gilmore, co-founder of the Electronic
+Frontier Foundation, a leading online civil rights group.
+
+Press contacts:
+Hugh Daniel,   +1 408 353 8124, hugh@toad.com
+Henry Spencer, +1 416 690 6561, henry@spsystems.net
+
+* FreeS/WAN derives its name from S/WAN, which is a trademark of RSA Data
+  Security, Inc; used by permission.</pre>
+</body>
+</html>
diff --git a/doc/src/quickstart-configs.html b/doc/src/quickstart-configs.html
new file mode 100644
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@@ -0,0 +1,144 @@
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>Quick FreeS/WAN installation and configuration</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, FreeSWAN, installation, quickstart">
+  <!--
+
+  Written by Sandy Harris for the Linux FreeS/WAN project
+  Revised by Claudia Schmeing for same
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  This is a new file derived from:
+  RCS ID:          $Id: quickstart-configs.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+<BODY>
+<H1><A name="quick_configs">FreeS/WAN quick start examples</A></H1>
+<P>These are sample 
+<A href="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</A>
+configuration files for opportunistic encryption, with comments. Much of 
+this configuration will be unnecessary with the new defaults proposed
+for FreeS/WAN 2.x.</P>
+<P>Full instructions are in our
+<A href="quickstart.html#quickstart">quickstart guide</A>.
+
+<H2><A name="qc.opp.client">Configuration for Initiate-only Opportunistic Encryption</A></H2>
+<P>The ipsec.conf file for an initiate-only opportunistic setup is:</P>
+<PRE># general IPsec setup
+config setup
+        # Use the default interface
+        interfaces=%defaultroute
+        # Use auto= parameters in conn descriptions to control startup actions.
+        plutoload=%search
+        plutostart=%search
+        uniqueids=yes
+
+# defaults for subsequent connection descriptions
+conn %default
+        # How to authenticate gateways
+        authby=rsasig
+        # default is
+        # load connection description into Pluto's database
+        # so it can respond if another gatway initiates
+        # individual connection descriptions may override this
+        auto=add
+
+# description for opportunistic connections
+conn me-to-anyone
+        left=%defaultroute         # all connections should use default route
+        right=%opportunistic       # anyone we can authenticate
+        leftrsasigkey=%dnsondemand  # NEW: look up keys in DNS as-needed
+        rightrsasigkey=%dnsondemand # (not at connection load time)
+        rekey=no                   # let unused connections die
+        keylife=1h                 # short
+        auto=route                 # set up for opportunistic
+        leftid=@xy.example.com     # our identity for IPSec negotiations
+                                   # must match DNS and ipsec.secrets</PRE>
+
+<P>Normally, you need to do only two things:</P>
+<UL>
+  <LI>edit <VAR>leftid=</VAR></LI>
+  <LI>set <VAR>auto=route</VAR></LI>
+</UL>
+<P>
+ However, some people may need to customize the <VAR>interfaces=</VAR> line
+ in the "config setup" section. All other sections are identical for any
+ standalone machine doing opportunistic encryption.</P>
+<P>The @ sign in the <VAR>leftid=</VAR> makes the ID go "over the wire"
+ as a Fully Qualified Domain Name (FQDN).  Without it, an IP address would
+ be used and this won't work.</P>
+<P>The conn is not used to supply either public key. Your private key
+ is in <A href="manpage.d/ipsec.secrets.5.html">ipsec.secrets(5)</A>
+ and, for opportunistic encryption, the public keys for remote gateways
+ are all looked up in DNS.</P>
+<P>FreeS/WAN authenticates opportunistic encryption by <A href="#gen_rsa">RSA
+ signature</A> only, so "public key" and "private key" refer to these keys.</P>
+<P>While the <VAR>left</VAR> and <VAR>right</VAR> designations
+ here are arbitrary, we follow a convention of using <VAR>left</VAR> for
+ local and <VAR>right</VAR> for remote.</P>
+
+<P><A href="quickstart.html#config.opp.client">Continue configuring
+initiate-only opportunism.</A>
+
+<H2><A name="qc.incoming.opp.conf">ipsec.conf for Incoming Opportunistic Encryption</A></H2>
+Use the ipsec.conf above, except that the section describing opportunistic
+connections is now:</P>
+<PRE>
+# description for opportunistic connections
+conn me-to-anyone
+        left=%defaultroute         # all connections should use default route
+        right=%opportunistic       # anyone we can authenticate
+        leftrsasigkey=%dnsondemand  # NEW: look up keys in DNS as-needed
+        rightrsasigkey=%dnsondemand # (not at connection load time)
+        rekey=no                   # let unused connections die
+        keylife=1h                 # short
+        auto=route                 # set up for opportunistic</PRE>
+
+<P>Note that <VAR>leftid=</VAR> has been removed. With no explicit setting,
+<VAR>leftid=</VAR> defaults to the IP of your public interface.</P>
+
+<P><A href="quickstart.html#incoming.opp.conf">Continue configuring
+full opportunism.</A>
+
+
+<H2><A name="qc.gate.opp.conf">ipsec.conf for Opportunistic Gateway</A></H2>
+Use the ipsec.conf above, plus these connections:
+
+<PRE>conn subnet-to-anyone            # must be above me-to-anyone
+       also=me-to-anyone
+       leftsubnet=42.42.42.0/24
+
+conn me-to-anyone                # just like for full opportunism
+        left=%defaultroute
+        right=%opportunistic
+        leftrsasigkey=%dnsondemand
+        rightrsasigkey=%dnsondemand
+        keylife=1h
+        rekey=no
+        auto=route               # be sure this is enabled
+                                 # Note there is NO leftid= </PRE>
+
+
+<P>Note that a subnet described in ipsec.conf(5) need not correspond to a
+ physical network segment. This is discussed in more detail in our
+<A href="adv_config.html">advanced configuration</A> document.</P>
+
+<P>If required, a gateway can easily provide this service for more than one
+ subnet. You just add a connection description for each.</P>
+
+<P><A href="quickstart.html#config.opp.gate">Continue configuring an
+opportunistic gateway.</A>
+
+
+</BODY>
+</HTML>
+
diff --git a/doc/src/quickstart-firewall.html b/doc/src/quickstart-firewall.html
new file mode 100644
index 000000000..53c27b5af
--- /dev/null
+++ b/doc/src/quickstart-firewall.html
@@ -0,0 +1,187 @@
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>Quick FreeS/WAN installation and configuration</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, FreeSWAN, installation, quickstart">
+  <!--
+
+  Written by Sandy Harris for the Linux FreeS/WAN project
+  Revised by Claudia Schmeing for same
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  RCS ID:          $Id: quickstart-firewall.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+<BODY>
+<H1><A name="quick_firewall">FreeS/WAN quick start on firewalling</A></H1>
+<P>This firewalling information supplements our
+<A HREF="quickstart.html#quick_guide">quickstart guide.</A></P>
+<P>It includes tips for firewalling:</P>
+<UL>
+<LI><A HREF="#firewall.standalone">a standalone system with initiator-only 
+opportunism</A></LI>
+<LI><A HREF="#incoming.opp.firewall">incoming opportunistic connections</A></LI>
+<LI><A HREF="#opp.gate.firewall">an opportunistic gateway</A></LI>
+</UL>
+<P>and a list of helpful <A HREF="#resources">resources</A>.</P>
+<H2><A name="firewall.standalone">Firewalling a standalone system</A></H2>
+<P>Firewall rules on a standalone system doing IPsec can be very simple.</P>
+<P>The first step is to allow IPsec packets (IKE on UDP port 500 plus
+ ESP, protocol 50) in and out of your gateway. A script to set up
+ iptables(8) rules for this is:</P>
+<PRE># edit this line to match the interface you use as default route
+# ppp0 is correct for many modem, DSL or cable connections
+# but perhaps not for you
+world=ppp0
+#
+# allow IPsec
+#
+# IKE negotiations
+iptables -A INPUT  -p udp -i $world --sport 500 --dport 500 -j ACCEPT
+iptables -A OUTPUT -p udp -o $world --sport 500 --dport 500 -j ACCEPT
+# ESP encryption and authentication
+iptables -A INPUT  -p 50 -i $world -j ACCEPT
+iptables -A OUTPUT -p 50 -o $world -j ACCEPT</PRE>
+<P>Optionally, you could restrict this, allowing these packets only to
+ and from a list of known gateways.</P>
+<P>A second firewalling step -- access controls built into the IPsec
+ protocols -- is automatically applied:</P>
+<DL>
+<DT><A href="glossary.html#Pluto">Pluto</A> -- the FreeS/WAN keying
+ daemon -- deals with the IKE packets.</DT>
+<DD>Pluto authenticates its partners during the IKE negotiation, and
+ drops negotiation if authentication fails.</DD>
+<DT><A href="glossary.html#KLIPS">KLIPS</A> -- the FreeS/WAN kernel
+ component -- handles the ESP packets.</DT>
+<DD>
+<DL>
+<DT>KLIPS drops outgoing packets</DT>
+<DD>if they are routed to IPsec, but no tunnel has been negotiated for
+ them</DD>
+<DT>KLIPS drops incoming unencrypted packets</DT>
+<DD>if source and destination addresses match a tunnel; the packets
+ should have been encrypted</DD>
+<DT>KLIPS drops incoming encrypted packets</DT>
+<DD>if source and destination address do not match the negotiated
+ parameters of the tunnel that delivers them</DD>
+<DD>if packet-level authentication fails</DD>
+</DL>
+</DD>
+</DL>
+<P>These errors are logged. See our <A href="trouble.html">
+ troubleshooting</A> document for details.</P>
+<P>As an optional third step, you may wish to filter packets emerging from 
+ your opportunistic tunnels.
+ These packets arrive on an interface such as <VAR>ipsec0</VAR>, rather than
+ <VAR>eth0</VAR>, <VAR>ppp0</VAR> or whatever. For example, in an iptables(8)
+ rule set, you would use:</P>
+<DL>
+<DT><VAR>-i ipsec+</VAR></DT>
+<DD>to specify packets arriving on any ipsec device</DD>
+<DT><VAR>-o ipsec+</VAR></DT>
+<DD>to specify packets leaving via any ipsec device</DD>
+</DL>
+<P>In this way, you can apply whatever additional filtering you like to these
+packets.</P>
+<P>The packets emerging on <VAR>ipsec0</VAR> are likely
+ to be things that a client application on your machine requested: web 
+ pages, e-mail, file transfers and so on. However, any time you initiate
+ an opportunistic connection, you open a two-way connection to
+ another machine (or network). It is conceivable that a Bad Guy there 
+ could take advantage of your link.</P>
+<P>For more information, read the next section.</P>
+</P>
+<H2><A name="incoming.opp.firewall">Firewalling incoming opportunistic
+ connections</A></H2>
+<P>The basic firewalling for IPsec does not change when you support
+ incoming connections as well as connections you initiate. You must
+ still allow IKE (UDP port 500) and ESP (protocol 50) packets to and
+ from your machine, as in the rules given <A href="#firewall.standalone">
+ above</A>.</P>
+<P>However, there is an additional security concern when you allow
+ incoming opportunistic connections. Incoming opportunistic packets
+ enter your machine via an IPSec tunnel. That is, they all appear as
+ ESP (protocol 50) packets, concealing whatever port and protocol
+ characteristics the packet within the tunnel has. Contained
+ in the tunnel as they pass through <VAR>ppp0</VAR> or <VAR>eth0</VAR>,
+ these packets can bypass your usual firewall rules on these interfaces.
+<P>Consequently, you will want to firewall your <VAR>ipsec</VAR> interfaces
+ the way you would any publicly accessible interface.</P>
+<P>A simple way to do this is to create one iptables(8) table with
+ all your filtering rules for incoming packets, and apply the entire table to
+ all public interfaces, including <VAR>ipsec</VAR> interfaces.</P>
+
+<H2><A name="opp.gate.firewall">Firewalling for opportunistic gateways</A></H2>
+<P>On a gateway, the IPsec-related firewall rules applied for input and
+ output on the Internet side are exactly as shown 
+<A HREF="#firewall.standalone">above</A>. A gateway
+ exchanges exactly the same things -- UDP 500 packets and IPsec packets
+ -- with other gateways that a standalone system does, so it can use
+ exactly the same firewall rules as a standalone system would.</P>
+<P>However, on a gateway there are additional things to do:</P>
+<UL>
+<LI>you have other interfaces and need rules for them</LI>
+<LI>packets emerging from ipsec processing must be correctly forwarded</LI>
+</UL>
+<P>You need additional rules to handle these things. For example, adding
+ some rules to the set shown above we get:</P>
+<PRE># edit this line to match the interface you use as default route
+# ppp0 is correct for many modem, DSL or cable connections
+# but perhaps not for you
+world=ppp0
+#
+# edit these lines to describe your internal subnet and interface
+localnet=42.42.42.0/24
+internal=eth1
+#
+# allow IPsec
+#
+# IKE negotiations
+iptables -A INPUT  -p udp -i $world --sport 500 --dport 500 -j ACCEPT
+iptables -A OUTPUT -p udp -o $world --sport 500 --dport 500 -j ACCEPT
+# ESP encryption and authentication
+iptables -A INPUT  -p 50 -i $world -j ACCEPT
+iptables -A OUTPUT -p 50 -o $world -j ACCEPT
+#
+# packet forwarding for an IPsec gateway
+# simplest possible rules
+$ forward everything, with no attempt to filter
+#
+# handle packets emerging from IPsec
+# ipsec+ means any of ipsec0, ipsec1, ...
+iptables -A FORWARD -d $localnet -i ipsec+ -j ACCEPT
+# simple rule for outbound packets
+# let local net send anything
+# IPsec will encrypt some of it
+iptables -A FORWARD -s $localnet -i $internal -j ACCEPT </PRE>
+<P>On a production gateway, you would no doubt need tighter rules than
+ the above.</P>
+<H2><A NAME="resources">Firewall resources</A></H2>
+<P>For more information, see these handy resources:</P>
+<UL>
+<LI><A href="http://www.netfilter.org/documentation/">netfilter
+ documentation</A></LI>
+<LI>books such as:
+<UL>
+<LI>Cheswick and Bellovin, <A href="biblio.html#firewall.book">Firewalls
+ and Internet Security</A></LI>
+<LI>Zeigler, <A href="biblio.html#Zeigler">Linux Firewalls</A>,</LI>
+</UL>
+</LI>
+<LI><A href="firewall.html#firewall">our firewalls document</A></LI>
+<LI><A href="web.html#firewall.web">our firewall links</A></LI>
+</UL>
+<A HREF="quickstart.html#quick.firewall">Back to our quickstart guide.</A>
+</BODY>
+</HTML>
+
+
+
diff --git a/doc/src/quickstart.html b/doc/src/quickstart.html
new file mode 100644
index 000000000..a74c11774
--- /dev/null
+++ b/doc/src/quickstart.html
@@ -0,0 +1,458 @@
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>Quick FreeS/WAN installation and configuration</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, FreeSWAN, installation, quickstart">
+  <!--
+
+  Written by Sandy Harris for the Linux FreeS/WAN project
+  Revised by Claudia Schmeing for same
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: quickstart.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+<BODY>
+<H1><A name="quickstart">Quickstart Guide to Opportunistic Encryption</A></H1>
+<A name="quick_guide"></A>
+
+<H2><A name="opp.setup">Purpose</A></H2>
+
+<P>This page will get you started using Linux FreeS/WAN with opportunistic
+ encryption (OE). OE enables you to set up IPsec tunnels
+ without co-ordinating with another
+ site administrator, and without hand configuring each tunnel.
+ If enough sites support OE, a &quot;FAX effect&quot; occurs, and
+ many of us can communicate without eavesdroppers.</P>
+
+<H3>OE "flag day"</H3>
+
+<P>As of FreeS/WAN 2.01, OE uses DNS TXT resource records (RRs)
+only (rather than TXT with KEY). 
+This change causes a 
+<a href="http://jargon.watson-net.com/jargon.asp?w=flag+day">"flag day"</a>.
+Users of FreeS/WAN 2.00 (or earlier) OE who are upgrading may require 
+additional resource records, as detailed in our 
+<a href="upgrading.html#upgrading.flagday">upgrading document</a>. 
+OE setup instructions here are for 2.02 or later.</P>
+
+
+<H2><A name="opp.dns">Requirements</A></H2>
+
+<P>To set up opportunistic encryption, you will need:</P>
+<UL>
+<LI>a Linux box. For OE to the public Internet, this box must NOT 
+be behind <A HREF="glossary.html#NAT.gloss">Network Address Translation</A>
+(NAT).</LI>
+<LI>to install Linux FreeS/WAN 2.02 or later</LI>
+<LI>either control over your reverse DNS (for full opportunism) or 
+the ability to write to some forward domain (for initiator-only). 
+<A HREF="http://www.fdns.net">This free DNS service</A> explicitly 
+supports forward TXT records for FreeS/WAN use.</LI>
+<LI>(for full opportunism) a static IP</LI>
+</UL>
+
+<P>Note: Currently, only Linux FreeS/WAN supports opportunistic 
+encryption.</P>
+
+<H2><A name="easy.install">RPM install</A></H2>
+
+<P>Our instructions are for a recent Red Hat with a 2.4-series stock or 
+Red Hat updated kernel. For other ways to install, see our 
+<A href="install.html#install">install document</A>.</P>
+
+
+<H3>Download RPMs</H3>
+
+<P>If we have prebuilt RPMs for your Red Hat system, 
+this command will get them:
+</P>
+
+<PRE>    ncftpget ftp://ftp.xs4all.nl/pub/crypto/freeswan/binaries/RedHat-RPMs/`uname -r | tr -d 'a-wy-z'`/\*</PRE>
+
+<P>If that fails, you will need to try <A HREF="install.html">another install 
+method</A>. 
+Our kernel modules 
+<B>will only work on the Red Hat kernel they were built for</B>,
+since they are very sensitive to small changes in the kernel.</P>
+
+<P>If it succeeds, you will have userland tools, a kernel module, and an 
+RPM signing key:</P>
+
+<PRE>    freeswan-module-2.04_2.4.20_20.9-0.i386.rpm
+    freeswan-userland-2.04_2.4.20_20.9-0.i386.rpm
+    freeswan-rpmsign.asc</PRE>
+
+
+<H3>Check signatures</H3>
+
+<P>If you're running RedHat 8.x or later, import the RPM signing key into the 
+RPM database:</P>
+<PRE>    rpm --import freeswan-rpmsign.asc</PRE>
+ 
+<P>For RedHat 7.x systems, you'll need to add it to your 
+<A HREF="glossary.html#PGP">PGP</A> keyring:</P>
+<PRE>    pgp -ka freeswan-rpmsign.asc</PRE>
+
+<P>Check the digital signatures on both RPMs using:</P>
+<PRE>    rpm --checksig freeswan*.rpm </PRE>
+
+<P>You should see that these signatures are good:</P>
+<PRE>    freeswan-module-2.04_2.4.20_20.9-0.i386.rpm: pgp md5 OK
+    freeswan-userland-2.04_2.4.20_20.9-0.i386.rpm: pgp md5 OK</PRE>
+
+
+<H3>Install the RPMs</H3>
+
+<P>Become root:</P>
+<PRE>    su</PRE>
+
+<P>Install your RPMs with:<P>
+<PRE>    rpm -ivh freeswan*.rpm</PRE>
+
+<P>If you're upgrading from FreeS/WAN 1.x RPMs, and have problems with that
+command, see 
+<A HREF="upgrading.html#upgrading.rpms">this note</A>.</P>
+
+<P>Then, start FreeS/WAN:</P>
+<PRE>    service ipsec start</PRE>
+
+
+<H3><A name="testinstall">Test</A></H3>
+<P>To check that you have a successful install, run:</P>
+<PRE>    ipsec verify</PRE>
+
+<P>You should see as part of the <var>verify</var> output:</P>
+<PRE>
+    Checking your system to see if IPsec got installed and started correctly
+    Version check and ipsec on-path                             [OK]
+    Checking for KLIPS support in kernel                        [OK]
+    Checking for RSA private key (/etc/ipsec.secrets)           [OK]
+    Checking that pluto is running                              [OK]
+    ...</PRE>
+
+<P>If any of these first four checks fails, see our 
+<A href="trouble.html#install.check">troubleshooting guide</A>.
+</P>
+
+<H2><A name="opp.setups.list">Our Opportunistic Setups</A></H2>
+<H3>Full or partial opportunism?</H3>
+<P>Determine the best form of opportunism your system can support.</P>
+<UL>
+<LI>For <A HREF="#opp.incoming">full opportunism</A>, you'll need a static
+IP and and either control over your reverse DNS or an ISP
+that can add the required TXT record for you.</LI>
+<LI>If you have a dynamic IP, and/or write access to forward DNS only,
+you can do <A HREF="#opp.client">initiate-only opportunism</A></LI>
+<LI>To protect traffic bound for real IPs behind your gateway, use
+<A HREF="adv_config.html#opp.gate">this form of full opportunism</A>.</LI>
+</UL>
+
+<H2><A name="opp.client">Initiate-only setup</A></H2>
+
+<H3>Restrictions</H3>
+<P>When you set up initiate-only Opportunistic Encryption (iOE):</P>
+<UL>
+<LI>there will be <STRONG> no incoming connection requests</STRONG>; you
+ can initiate all the IPsec connections you need.</LI>
+<LI><STRONG>only one machine is visible</STRONG> on your end of the
+ connection.</LI>
+<LI>iOE also protects traffic on behalf of 
+<A HREF="glossary.html#NAT.gloss">NATted</A> hosts behind the iOE box.</LI>
+</UL>
+<P>You cannot network a group of initiator-only machines if none
+of these is capable of responding to OE. If one is capable of responding, 
+you may be able to create a hub topology using routing.</P>
+
+
+<H3><A name="forward.dns">Create and publish a forward DNS record</A></H3>
+
+<H4>Find a domain you can use</H4>
+
+<P>Find a DNS forward domain (e.g. example.com) where you can publish your key. 
+You'll need access to the DNS zone files for that domain.  
+This is common for a domain you own. Some free DNS providers, 
+such as <A HREF="http://www.fdns.net">this one</A>, also provide 
+this service.</P>
+
+<P>Dynamic IP users take note: the domain where you place your key
+ need not be associated with the IP address for your system, 
+ or even with your system's usual hostname.</P>
+
+<H4>Choose your ID</H4>
+
+<P>Choose a name within that domain which you will use to identify your 
+ machine. It's convenient if this can be the same as your hostname:</P>
+<PRE>    [root@xy root]# hostname --fqdn
+    xy.example.com</PRE>
+<P>This name in FQDN (fully-qualified domain name)
+format will be your ID, for DNS key lookup and IPsec
+negotiation.</P>
+
+
+<H4>Create a forward TXT record</H4>
+
+<P>Generate a forward TXT record containing your system's public key
+ with a command like:</P>
+<PRE>    ipsec showhostkey --txt @xy.example.com</PRE>
+<P>using your chosen ID in place of 
+xy.example.com.
+This command takes the contents of
+/etc/ipsec.secrets and reformats it into something usable by ISC's BIND.
+ The result should look like this (with the key data trimmed down for
+ clarity):</P>
+<PRE>
+    ; RSA 2192 bits   xy.example.com   Thu Jan  2 12:41:44 2003
+        IN      TXT     "X-IPsec-Server(10)=@xy.example.com" 
+    "AQOF8tZ2... ...+buFuFn/"
+</PRE>
+
+
+<H4>Publish the forward TXT record</H4>
+
+<P>Insert the record into DNS, or have a system adminstrator do it
+for you. It may take up to 48 hours for the record to propagate, but 
+it's usually much quicker.</P>
+
+<H3>Test that your key has been published</H3>
+
+<P>Check your DNS work</P>
+
+<PRE>    ipsec verify --host xy.example.com</PRE>
+
+<P>As part of the <var>verify</var> output, you ought to see something 
+like:</P>
+
+<PRE>    ...
+    Looking for TXT in forward map: xy.example.com          [OK]
+    ...</PRE>
+
+<P>For this type of opportunism, only the forward test is relevant;
+you can ignore the tests designed to find reverse records.</P>
+
+
+<H3>Configure, if necessary</H3>
+
+<P>
+If your ID is the same as your hostname,
+you're ready to go.
+FreeS/WAN will use its 
+<A HREF="policygroups.html">built-in connections</A> to create 
+your iOE functionality.
+</P>
+
+<P>If you have chosen a different ID, you must tell FreeS/WAN about it via
+<A HREF="manpage.d/ipsec.conf.5.html"><VAR>ipsec.conf</VAR></A>:
+
+<PRE>    config setup
+        myid=@myname.freedns.example.com</PRE>
+
+<P>and restart FreeS/WAN:
+</P>
+<PRE>    service ipsec restart</PRE>
+<P>The new ID will be applied to the built-in connections.</P>
+
+<P>Note: you can create more complex iOE configurations as explained in our
+<A HREF="policygroups.html#policygroups">policy groups document</A>, or
+disable OE using
+<A HREF="policygroups.html#disable_policygroups">these instructions</A>.</P>
+
+
+<H3>Test</H3>
+<P>That's it! <A HREF="#opp.test">Test your connections</A>.</P>
+
+<A name="opp.incoming"></A><H2>Full Opportunism</H2>
+
+<P>Full opportunism
+allows you to initiate and receive opportunistic connections on your
+machine.</P>
+
+<A name="incoming.opp.dns"></A><H3>Put a TXT record in a Forward Domain</H3>
+
+<P>To set up full opportunism, first
+<A HREF="#forward.dns">set up a forward TXT record</A> as for 
+<A HREF="#opp.client">initiator-only OE</A>, using
+an ID (for example, your hostname) that resolves to your IP. Do not
+configure <VAR>/etc/ipsec.conf</VAR>, but continue with the
+instructions for full opportunism, below.
+</P>
+
+<P>Note that this forward record is not currently necessary for full OE, 
+but will facilitate future features.</P>
+
+
+<A name="incoming.opp.dns"></A><H3>Put a TXT record in Reverse DNS</H3>
+
+<P>You must be able to publish your DNS RR directly in the reverse domain.
+FreeS/WAN will not follow a PTR which appears in the reverse, since 
+a second lookup at connection start time is too costly.</P>
+
+
+<H4>Create a Reverse DNS TXT record</H4>
+
+<P>This record serves to publicize your FreeS/WAN public key. In 
+ addition, it lets others know that this machine can receive opportunistic 
+connections, and asserts that the machine is authorized to encrypt on 
+its own behalf.</P>
+
+<P>Use the command:</P>
+<PRE>    ipsec showhostkey --txt 192.0.2.11</PRE>
+<P>where you replace 192.0.2.11 with your public IP.</P>
+
+<P>The record (with key shortened) looks like:</P>
+<PRE>    ; RSA 2048 bits  xy.example.com   Sat Apr 15 13:53:22 2000
+    IN TXT  &quot;X-IPsec-Server(10)=192.0.2.11&quot; &quot; AQOF8tZ2...+buFuFn/&quot;</PRE>
+
+
+<H4>Publish your TXT record</H4>
+
+<P>Send these records to your ISP, to be published in your IP's reverse map.
+It may take up to 48 hours for these to propagate, but usually takes
+much less time.</P>
+
+
+<H3>Test your DNS record</H3>
+
+<P>Check your DNS work with</P>
+
+<PRE>    ipsec verify --host xy.example.com</PRE>
+
+<P>As part of the <var>verify</var> output, you ought to see something like:</P>
+
+<PRE>    ...
+    Looking for TXT in reverse map: 11.2.0.192.in-addr.arpa [OK]
+    ...</PRE>
+
+<P>which indicates that you've passed the reverse-map test.</P>
+
+<H3>No Configuration Needed</H3>
+
+<P>FreeS/WAN 2.x ships with full OE enabled, so you don't need to configure 
+anything.
+To enable OE out of the box, FreeS/WAN 2.x uses the policy group
+<VAR>private-or-clear</VAR>,
+which creates IPsec connections if possible (using OE if needed), 
+and allows traffic in the clear otherwise. You can create more complex 
+OE configurations as described in our
+<A HREF="policygroups.html#policygroups">policy groups document</A>, or 
+disable OE using 
+<A HREF="policygroups.html#disable_policygroups">these instructions</A>.</P>
+
+<P>If you've previously configured for initiator-only opportunism, remove 
+ <VAR>myid=</VAR> from <VAR>config setup</VAR>, so that peer FreeS/WANs 
+will look up your key by IP. Restart FreeS/WAN so that your change will 
+take effect, with</P>
+
+<PRE>    service ipsec restart</PRE>
+
+
+<H3>Consider Firewalling</H3>
+
+<P>If you are running a default install of RedHat 8.x, take note: you will
+need to alter your iptables rule setup to allow IPSec traffic through your
+firewall. See <A HREF="firewall.html#simple.rules">our firewall document</A>
+for sample <VAR>iptables</VAR> rules.</P>
+
+
+<H3>Test</H3>
+
+<P>That's it. Now, <A HREF="#opp.test">test your connection</A>.
+
+
+
+
+<H3>Test</H3>
+
+<P>Instructions are in the next section.</P>
+
+
+<H2><A NAME="opp.test">Testing opportunistic connections</A></H2>
+
+<P>Be sure IPsec is running. You can see whether it is with:</P>
+<PRE>    ipsec setup status</PRE>
+<P>If need be, you can restart it with:</P>
+<PRE>    service ipsec restart</PRE>
+
+<P>Load a FreeS/WAN test website from the host on which you're running
+FreeS/WAN. Note: the feds may be watching these sites. Type one of:<P>
+<PRE>   links oetest.freeswan.org</PRE>
+<PRE>   links oetest.freeswan.nl</PRE>
+<!--<PRE>   links oetest.freeswan.ca</PRE>-->
+
+<P>A positive result looks like this:</P>
+
+<PRE>
+   You  seem  to  be  connecting  from:  192.0.2.11 which DNS says is:
+   gateway.example.com
+     _________________________________________________________________
+
+   Status E-route
+   OE    enabled    16    192.139.46.73/32    ->    192.0.2.11/32   =>
+   tun0x2097@192.0.2.11
+   OE    enabled    176    192.139.46.77/32    ->   192.0.2.11/32   =>
+   tun0x208a@192.0.2.11
+</PRE>
+
+<P>If you see this, congratulations! Your OE host or gateway will now encrypt 
+its own traffic whenever it can. For more OE tests, please see our
+<A HREF="testing.html#test.oe">testing document</A>. If you have difficulty, 
+see our <A HREF="#oe.trouble">OE troubleshooting tips</A>.
+</P>
+
+
+
+<H2>Now what?</H2>
+
+<P>Please see our <A HREF="policygroups.html">policy groups document</A>
+for more ways to set up Opportunistic Encryption.</P>
+
+<P>You may also wish to make some <A HREF="config.html">
+pre-configured connections</A>.
+</P>
+
+<H2>Notes</H2>
+
+<UL>
+<LI>We assume some facts about your system in order to make Opportunistic
+Encryption easier to configure. For example, we assume that you wish
+to have FreeS/WAN secure your default interface.</LI>
+<LI>You may change this, and other settings, by altering the
+<VAR>config setup</VAR> section in 
+<VAR>/etc/ipsec.conf</VAR>.
+</LI>
+<LI>Note that the built-in connections used to build policy groups do 
+not inherit from <VAR>conn default</VAR>.</LI>
+<!--
+<LI>If you do not define your local identity
+(eg. <VAR>leftid</VAR>), this will be the IP address of your default
+FreeS/WAN interface.  
+-->
+<LI>
+If you fail to define your local identity and
+do not fill in your reverse DNS entry, you will not be able to use OE.</LI>
+</UL>
+
+<A NAME="oe.trouble"></A><H2>Troubleshooting OE</H2>
+
+<P>See the OE troubleshooting hints in our 
+<A HREF="trouble.html#oe.trouble">troubleshooting guide</A>.
+</P>
+
+<A NAME="oe.known-issues"></A><H2>Known Issues</H2>
+
+<P>Please see 
+<A HREF="opportunism.known-issues">this list</A> of known issues
+with Opportunistic Encryption.</P>
+
+
+</BODY>
+</HTML>
diff --git a/doc/src/reference.ESPUDP.xml b/doc/src/reference.ESPUDP.xml
new file mode 100644
index 000000000..c9b96cef3
--- /dev/null
+++ b/doc/src/reference.ESPUDP.xml
@@ -0,0 +1,34 @@
+<?xml version='1.0'?>
+<!DOCTYPE reference SYSTEM 'rfc2629.dtd'>
+
+<reference anchor='ESPUDP'>
+
+<front>
+<title abbrev='UDPESP'>UDP Encapsulation of IPsec Packets</title>
+<author initials='A.' surname='Huttunen' fullname='Ari Huttunen'>
+<organization>F-Secure Corporation</organization>
+<address>
+<postal>
+<street>Tammasaarenkatu 7</street>
+<street>FIN-00181 HELSINKI</street>
+<country>Finland</country></postal>
+<email>Ari.Huttunen@F-Secure.com</email></address></author>
+
+<author initials='W.' surname='Dixon' fullname='William Dixon'>
+<organization>Microsoft</organization>
+<address>
+<postal>
+<street>One Microsoft Way</street>
+<street>Redmond</street>
+<street>WA 98052</street>
+<country>USA</country></postal>
+<email>wdixon@microsoft.com</email></address></author>
+
+<date month='June' year='2001'></date>
+<area>Security</area>
+<keyword>IP security protocol</keyword>
+<keyword>IPSEC</keyword>
+<keyword>security</keyword></front>
+
+<seriesInfo name='ID' value='internet-draft (draft-ietf-ipsec-udp-encaps-00) (informative)' />
+</reference>
diff --git a/doc/src/reference.KEYRESTRICT.xml b/doc/src/reference.KEYRESTRICT.xml
new file mode 100644
index 000000000..62aa1ef96
--- /dev/null
+++ b/doc/src/reference.KEYRESTRICT.xml
@@ -0,0 +1,31 @@
+<?xml version='1.0'?>
+<!DOCTYPE reference SYSTEM 'rfc2629.dtd'>
+
+<reference anchor='KEYRESTRICT'>
+
+<front>
+<title abbrev='KEYRESTRICT'>Limiting the Scope of the KEY Resource Record</title>
+<author initials='D.' surname='Massey' fullname='Dan Massey'>
+<organization>USC/ISI</organization>
+<address>
+<postal>
+<street>USC Informational Sciences Institute</street>
+<street>3811 North Fairfax Drive, Suite 200</street>
+<street>Arlington, VA 22203</street>
+<country>USA</country></postal>
+<email>masseyd@isi.edu</email></address></author>
+
+<author initials='S.' surname='Rose' fullname='Scott Rose'>
+<organization>National Institute for Standards and Technology</organization>
+<address>
+<postal>
+<street>Gaithersburg, MD</street>
+<country>USA</country></postal>
+<email>scott.rose@nist.gov</email></address></author>
+
+<date month='March' year='2002'></date>
+<area>Internet</area>
+</front>
+
+<seriesInfo name='ID' value='internet-draft (draft-ietf-dnsext-restrict-key-for-dnssec-02) (normative)' />
+</reference>
diff --git a/doc/src/reference.MODPGROUPS.xml b/doc/src/reference.MODPGROUPS.xml
new file mode 100644
index 000000000..5eaf83f89
--- /dev/null
+++ b/doc/src/reference.MODPGROUPS.xml
@@ -0,0 +1,32 @@
+<?xml version='1.0'?>
+<!DOCTYPE reference SYSTEM 'rfc2629.dtd'>
+
+<reference anchor='MODPGROUPS'>
+
+<front>
+<title abbrev='MODPGROUPS'>More MODP Diffie-Hellman groups for IKE</title>
+<author initials='T.' surname='Kivinen' fullname='Tero Kivinen'>
+<organization>SSH Communications Security</organization>
+<address>
+<postal>
+<street>Fredrikinkatu 42</street>
+<street>FIN-00100 HELSINKI</street>
+<country>Finland</country></postal>
+<email>kivinen@ssh.fi</email></address></author>
+
+<author initials='M.' surname='Kojo' fullname='Mika Kojo'>
+<organization>University of Helsinki</organization>
+<address>
+<postal>
+<street>HELSINKI</street>
+<country>Finland</country></postal>
+<email>mrskojo@cc.helsinki.fi</email></address></author>
+
+<date month='November' year='2001'></date>
+<area>Security</area>
+<keyword>IP security protocol</keyword>
+<keyword>IPSEC</keyword>
+<keyword>security</keyword></front>
+
+<seriesInfo name='ID' value='internet-draft (draft-ietf-ipsec-ike-modp-groups-03) (normative)' />
+</reference>
diff --git a/doc/src/reference.OEspec.xml b/doc/src/reference.OEspec.xml
new file mode 100644
index 000000000..29c6d6efd
--- /dev/null
+++ b/doc/src/reference.OEspec.xml
@@ -0,0 +1,45 @@
+<?xml version='1.0'?>
+<!DOCTYPE reference SYSTEM 'rfc2629.dtd'>
+
+<reference anchor='OEspec'>
+
+<front>
+<title abbrev='OEspec'>Opportunistic Encryption</title>
+
+  <author initials="D.H." surname="Redelmeier"
+          fullname="D. Hugh Redelmeier">
+    <organization abbrev="Mimosa">Mimosa</organization>
+    <address>
+      <postal>   
+      	<street>Somewhere</street>
+        <city>Toronto</city>
+        <region>ON</region>
+        <country>CA</country>
+      </postal>
+      <email>hugh@mimosa.com</email>
+    </address>
+  </author>
+
+  <author initials="H." surname="Spencer"
+          fullname="Henry Spencer">
+    <organization abbrev="SP Systems">SP Systems</organization>
+    <address>
+      <postal>
+      	<street>Box 280 Station A</street>
+	<city>Toronto</city>
+	<region>ON</region>
+	<code>M5W 1B2</code>
+	<country>Canada</country>
+      </postal>
+      <email>henry@spsystems.net</email>
+    </address>
+  </author>
+
+<date month='May' year='2001'></date>
+<keyword>IP security protocol</keyword>
+<keyword>IPSEC</keyword>
+<keyword>security</keyword></front>
+
+<seriesInfo name='paper' value='http://www.freeswan.org/freeswan_trees/freeswan-1.91/doc/opportunism.spec' />
+</reference>
+
diff --git a/doc/src/reference.RFC.3526.xml b/doc/src/reference.RFC.3526.xml
new file mode 100644
index 000000000..54fed705a
--- /dev/null
+++ b/doc/src/reference.RFC.3526.xml
@@ -0,0 +1,32 @@
+<?xml version='1.0'?>
+<!DOCTYPE reference SYSTEM 'rfc2629.dtd'>
+
+<reference anchor='RFC3526'>
+
+<front>
+<title abbrev='MODPGROUPS'>More MODP Diffie-Hellman groups for IKE</title>
+<author initials='T.' surname='Kivinen' fullname='Tero Kivinen'>
+<organization>SSH Communications Security</organization>
+<address>
+<postal>
+<street>Fredrikinkatu 42</street>
+<street>FIN-00100 HELSINKI</street>
+<country>Finland</country></postal>
+<email>kivinen@ssh.fi</email></address></author>
+
+<author initials='M.' surname='Kojo' fullname='Mika Kojo'>
+<organization>University of Helsinki</organization>
+<address>
+<postal>
+<street>HELSINKI</street>
+<country>Finland</country></postal>
+<email>mrskojo@cc.helsinki.fi</email></address></author>
+
+<date month='March' year='2003'></date>
+<area>Security</area>
+<keyword>IP security protocol</keyword>
+<keyword>IPSEC</keyword>
+<keyword>security</keyword></front>
+
+<seriesInfo name='RFC' value='3526' />
+</reference>
diff --git a/doc/src/responderstate.txt b/doc/src/responderstate.txt
new file mode 100644
index 000000000..f64b82983
--- /dev/null
+++ b/doc/src/responderstate.txt
@@ -0,0 +1,43 @@
+                |
+                | IKE main mode 
+                |  phase 1
+                V
+        .-----------------.  
+        | unauthenticated | 
+        |     OE peer     |
+        `-----------------'
+                |
+                | lookup KEY RR in in-addr.arpa 
+                |             (if ID_IPV4_ADDR)
+                | lookup KEY RR in forward
+                |             (if ID_FQDN)
+                V
+        .-----------------.  RR not found
+        |   received DNS  |---------------> log failure
+        |     reply       | 
+        `----+--------+---'
+     phase 2 |        \      misformatted 
+    proposal |         `------------------> log failure
+             V
+    .----------------.
+    |  authenticated |  identical initiator 
+    |     OE peer    |--------------------> initiator 
+    `----------------'  connection found    state machine
+         |
+         | look for TXT record for initiator
+	 |
+         V  
+   .---------------.
+   |  authorized   |---------------------> log failure
+   |    OE peer    |
+   `---------------'
+         |
+         |
+         V
+    potential OE
+    connection in
+    initiator state
+	machine
+
+
+$Id: responderstate.txt,v 1.1 2004/03/15 20:35:24 as Exp $
diff --git a/doc/src/rfc.html b/doc/src/rfc.html
new file mode 100644
index 000000000..762c66c6e
--- /dev/null
+++ b/doc/src/rfc.html
@@ -0,0 +1,158 @@
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>IPsec RFCs</title>
+  <meta name="keywords"
+  content="IPsec, VPN, security, FreeSWAN, RFC, standard">
+  <!--
+
+  Written by Sandy Harris for the Linux FreeS/WAN project
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: rfc.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+
+<body>
+<h1><a name="RFC">IPsec RFCs and related documents</a></h1>
+
+<h2><a name="RFCfile">The RFCs.tar.gz Distribution File</a></h2>
+
+<p>The Linux FreeS/WAN distribution is available from <a
+href="http://www.xs4all.nl/~freeswan"> our primary distribution site</a> and
+various mirror sites. To give people more control over their downloads, the
+RFCs that define IP security are bundled separately in the file
+RFCs.tar.gz.</p>
+
+<p>The file you are reading is included in the main distribution and is
+available on the web site. It describes the RFCs included in the <a
+href="#RFCs.tar.gz">RFCs.tar.gz</a> bundle and gives some pointers to <a
+href="#sources">other ways to get them</a>.</p>
+
+<h2><a name="sources">Other sources for RFCs &amp; Internet drafts</a></h2>
+
+<h3><a name="RFCdown">RFCs</a></h3>
+
+<p>RFCs are downloadble at many places around the net such as:</p>
+<ul>
+  <li><a href="http://www.rfc-editor.org">http://www.rfc-editor.org</a></li>
+  <li><a href="http://nis.nsf.net/internet/documents/rfc">NSF.net</a></li>
+  <li><a href="http://sunsite.doc.ic.ac.uk/computing/internet/rfc">Sunsite in
+    the UK</a></li>
+</ul>
+
+<p>browsable in HTML form at others such as:</p>
+<ul>
+  <li><a
+  href="http://www.landfield.com/rfcs/index.html">landfield.com</a></li>
+  <li><a href="http://www.library.ucg.ie/Connected/RFC">Connected Internet
+    Encyclopedia</a></li>
+</ul>
+
+<p>and some of them are available in translation:</p>
+<ul>
+  <li><a href="http://www.eisti.fr/eistiweb/docs/normes/">French</a></li>
+</ul>
+
+<p>There is also a published <a href="biblio.html#RFCs">Big Book of IPSEC
+RFCs</a>.</p>
+
+<h3><a name="drafts">Internet Drafts</a></h3>
+
+<p>Internet Drafts, working documents which sometimes evolve into RFCs, are
+also available.</p>
+<ul>
+  <li><a href="http://www.ietf.org/ID.html">Overall reference page</a></li>
+  <li><a href="http://www.ietf.org/ids.by.wg/ipsec.html">IPsec</a> working
+    group</li>
+  <li><a href="http://www.ietf.org/ids.by.wg/ipsra.html">IPSRA (IPsec Remote
+    Access)</a> working group</li>
+  <li><a href="http://www.ietf.org/ids.by.wg/ipsp.html">IPsec Policy</a>
+    working group</li>
+  <li><a href="http://www.ietf.org/ids.by.wg/kink.html">KINK (Kerberized
+    Internet Negotiation of Keys)</a>  working group</li>
+</ul>
+
+<p>Note: some of these may be obsolete, replaced by later drafts or by
+RFCs.</p>
+
+<h3><a name="FIPS1">FIPS standards</a></h3>
+
+<p>Some things used by <a href="glossary.html#IPSEC">IPsec</a>, such as <a
+href="glossary.html#DES">DES</a> and <a href="glossary.html#SHA">SHA</a>, are
+defined by US government standards called <a
+href="glossary.html#FIPS">FIPS</a>. The issuing organisation, <a
+href="glossary.html#NIST">NIST</a>, have a <a
+href="http://www.itl.nist.gov/div897/pubs">FIPS home page</a>.</p>
+
+<h2><a name="RFCs.tar.gz">What's in the RFCs.tar.gz bundle?</a></h2>
+
+<p>All filenames are of the form rfc*.txt, with the * replaced with the RFC
+number.</p>
+<pre>RFC#        Title</pre>
+
+<h3><a name="rfc.ov">Overview RFCs</a></h3>
+<pre>2401        Security Architecture for the Internet Protocol
+2411        IP Security Document Roadmap</pre>
+
+<h3><a name="basic.prot">Basic protocols</a></h3>
+<pre>2402        IP Authentication Header
+2406        IP Encapsulating Security Payload (ESP)</pre>
+
+<h3><a name="key.ike">Key management</a></h3>
+<pre>2367        PF_KEY Key Management API, Version 2
+2407        The Internet IP Security Domain of Interpretation for ISAKMP
+2408        Internet Security Association and Key Management Protocol (ISAKMP)
+2409        The Internet Key Exchange (IKE)
+2412        The OAKLEY Key Determination Protocol
+2528        Internet X.509 Public Key Infrastructure</pre>
+
+<h3><a name="rfc.detail">Details of various things used</a></h3>
+<pre>2085        HMAC-MD5 IP Authentication with Replay Prevention
+2104        HMAC: Keyed-Hashing for Message Authentication
+2202        Test Cases for HMAC-MD5 and HMAC-SHA-1
+2207        RSVP Extensions for IPSEC Data Flows
+2403        The Use of HMAC-MD5-96 within ESP and AH
+2404        The Use of HMAC-SHA-1-96 within ESP and AH
+2405        The ESP DES-CBC Cipher Algorithm With Explicit IV
+2410        The NULL Encryption Algorithm and Its Use With IPsec
+2451        The ESP CBC-Mode Cipher Algorithms
+2521        ICMP Security Failures Messages</pre>
+
+<h3><a name="rfc.ref">Older RFCs which may be referenced</a></h3>
+<pre>1321        The MD5 Message-Digest Algorithm
+1828        IP Authentication using Keyed MD5
+1829        The ESP DES-CBC Transform
+1851        The ESP Triple DES Transform
+1852        IP Authentication using Keyed SHA</pre>
+
+<h3><a name="rfc.dns">RFCs for secure DNS service, which IPsec may
+use</a></h3>
+<pre>2137        Secure Domain Name System Dynamic Update
+2230        Key Exchange Delegation Record for the DNS
+2535        Domain Name System Security Extensions
+2536        DSA KEYs and SIGs in the Domain Name System (DNS)
+2537        RSA/MD5 KEYs and SIGs in the Domain Name System (DNS)
+2538        Storing Certificates in the Domain Name System (DNS)
+2539        Storage of Diffie-Hellman Keys in the Domain Name System (DNS)</pre>
+
+<h3><a name="rfc.exp">RFCs labelled "experimental"</a></h3>
+<pre>2521        ICMP Security Failures Messages
+2522        Photuris: Session-Key Management Protocol
+2523        Photuris: Extended Schemes and Attributes</pre>
+
+<h3><a name="rfc.rel">Related RFCs</a></h3>
+<pre>1750        Randomness Recommendations for Security
+1918        Address Allocation for Private Internets
+1984        IAB and IESG Statement on Cryptographic Technology and the Internet
+2144        The CAST-128 Encryption Algorithm</pre>
+</body>
+</html>
diff --git a/doc/src/roadmap.html b/doc/src/roadmap.html
new file mode 100644
index 000000000..c9d85047c
--- /dev/null
+++ b/doc/src/roadmap.html
@@ -0,0 +1,203 @@
+<html>
+<head>
+<title>FreeS/WAN roadmap</title>
+<meta name="keywords" content="Linux, IPsec, VPN, security, FreeSWAN">
+
+<!--
+
+Written by Sandy Harris for the Linux FreeS/WAN project
+Freely distributable under the GNU General Public License
+
+More information at www.freeswan.org
+Feedback to users@lists.freeswan.org
+
+CVS information:
+RCS ID:          $Id: roadmap.html,v 1.1 2004/03/15 20:35:24 as Exp $
+Last changed:    $Date: 2004/03/15 20:35:24 $
+Revision number: $Revision: 1.1 $
+
+CVS revision numbers do not correspond to FreeS/WAN release numbers.
+-->
+</head>
+
+<body>
+<h1><a name="roadmap">Distribution Roadmap: What's Where in Linux FreeS/WAN</a></h1>
+
+<p>
+This file is a guide to the locations of files within the FreeS/WAN
+distribution. Everything described here should be on your system once you
+download, gunzip, and untar the distribution.</p>
+
+<p>This distribution contains two major subsystems
+</p>
+<dl>
+  <dt><a href="#klips.roadmap">KLIPS</a></dt>
+    <dd>the kernel code</dd>
+  <dt><a href="#pluto.roadmap">Pluto</a></dt>
+    <dd>the user-level key-management daemon</dd>
+</dl>
+
+<p>plus assorted odds and ends.
+</p>
+<h2><a name="top">Top directory</a></h2>
+
+<p>The top directory has essential information in text files:</p>
+
+<dl>
+  <dt>README</dt>
+    <dd>introduction to the software</dd>
+  <dt>INSTALL</dt>
+    <dd>short experts-only installation procedures. More detalied procedures are in
+      <a href="install.html">installation</a> and
+	<a href="config.html">configuration</a> HTML documents.</dd>
+  <dt>BUGS</dt>
+    <dd>major known bugs in the current release.</dd>
+  <dt>CHANGES</dt>
+    <dd>changes from previous releases</dd>
+  <dt>CREDITS</dt>
+    <dd>acknowledgement of contributors</dd>
+  <dt>COPYING</dt>
+    <dd>licensing and distribution information</dd>
+</dl>
+
+<h2><a name="doc">Documentation</a></h2>
+
+<p>
+The doc directory contains the bulk of the documentation, most of it in
+HTML format. See the <a href="index.html">index file</a> for details.
+</p>
+
+<h2><a name="klips.roadmap">KLIPS: kernel IP security</a></h2>
+</a>
+<p>
+<a href="glossary.html#KLIPS">KLIPS</a> is <strong>K</strong>erne<strong>L</strong>
+<strong>IP</strong> <strong>S</strong>ecurity. It lives in the klips
+directory, of course.
+</p>
+<dl>
+  <dt>klips/doc</dt>
+    <dd>documentation</dd>
+  <dt>klips/patches</dt>
+    <dd>patches for existing kernel files</dd>
+  <dt>klips/test</dt>
+    <dd>test stuff</dd>
+  <dt>klips/utils</dt>
+    <dd>low-level user utilities</dd>
+  <dt>klips/net/ipsec</dt>
+    <dd>actual klips kernel files</dd>
+  <dt>klips/src</dt>
+    <dd>symbolic link to klips/net/ipsec
+      <p>The "make insert" step of installation installs the patches and makes
+      a symbolic link from the kernel tree to klips/net/ipsec. The odd name of
+      klips/net/ipsec is dictated by some annoying limitations of the scripts
+      which build the Linux kernel.  The symbolic-link business is a bit
+      messy, but all the alternatives are worse.</p>
+      <p></p>
+    </dd>
+  <dt>klips/utils</dt>
+    <dd>Utility programs:
+      <p></p>
+      <dl>
+        <dt>eroute</dt>
+          <dd>manipulate IPsec extended routing tables</dd>
+        <dt>klipsdebug</dt>
+          <dd>set Klips (kernel IPsec support) debug features and level</dd>
+        <dt>spi</dt>
+          <dd>manage IPsec Security Associations</dd>
+        <dt>spigrp</dt>
+          <dd>group/ungroup IPsec Security Associations</dd>
+        <dt>tncfg</dt>
+          <dd>associate IPsec virtual interface with real interface</dd>
+      </dl>
+      <p>These are all normally invoked by ipsec(8) with commands such as</p>
+      <pre>        ipsec tncfg <var>arguments</var></pre>
+      There are section 8 man pages for all of these; the names have "ipsec_"
+      as a prefix, so your man command should be something like:
+      <pre>        man 8 ipsec_tncfg</pre>
+    </dd>
+</dl>
+
+<h2><a name="pluto.roadmap">Pluto key and connection management daemon</a></h2>
+
+<p>
+<a href="glossary.html#Pluto">Pluto</a> is our key management and negotiation daemon. It
+lives in the pluto directory, along with its low-level user utility,
+whack.
+</p>
+<p>
+There are no subdirectories. Documentation is a man page,
+<a href="manpage.d/ipsec_pluto.8.html">pluto.8</a>. This covers whack as well.
+</p>
+
+<h2><a name="utils">Utils</a></h2>
+
+<p>
+The utils directory contains a growing collection of higher-level user
+utilities, the commands that administer and control the software.  Most of the
+things that you will actually have to run yourself are in there.
+</p>
+<dl>
+  <dt>ipsec</dt>
+    <dd>invoke IPsec utilities
+      <p>ipsec(8) is normally the only program installed in a standard
+      directory, /usr/local/sbin. It is used to invoke the others, both those
+      listed below and the ones in klips/utils mentioned above.</p>
+      <p></p>
+    </dd>
+  <dt>auto</dt>
+    <dd>control automatically-keyed IPsec connections</dd>
+  <dt>manual</dt>
+    <dd>take manually-keyed IPsec connections up and down</dd>
+  <dt>barf</dt>
+    <dd>generate copious debugging output</dd>
+  <dt>look</dt>
+    <dd>generate moderate amounts of debugging output</dd>
+</dl>
+<p>
+There are .8 manual pages for these. look is covered in barf.8. The man pages
+have an "ipsec_" prefix so your man command should be something like:
+<pre>
+        man 8 ipsec_auto
+</pre>
+<p>
+Examples are in various files with names utils/*.eg</p>
+
+<h2><a name="lib">Libraries</a></h2>
+
+<h3><a name="fswanlib">FreeS/WAN Library</a></h3>
+
+<p>
+The lib directory is the FreeS/WAN library, also steadily growing, used by
+both user-level and kernel code.<br />
+It includes section 3 <a href="manpages.html">man pages</a> for the library routines.
+</p>
+<h3><a name="otherlib">Imported Libraries</a></h3>
+
+<h4>LibDES</h4>
+
+The libdes library, originally from SSLeay, is used by both Klips and Pluto
+for <a href="glossary.html#3DES">Triple DES</a> encryption. Single DES is not
+used because <a href="politics.html#desnotsecure">it is
+insecure</a>.
+<p>
+Note that this library has its own license, different from the
+<a href="glossary.html#GPL">GPL</a> used for other code in FreeS/WAN.
+ </p>
+<p>
+The library includes its own documentation.
+
+
+<h4>GMP</h4>
+
+The GMP (GNU multi-precision) library is used for multi-precision arithmetic
+in Pluto's key-exchange code and public key code.
+<p>
+Older versions (up to 1.7) of FreeS/WAN included a copy of this library in
+the FreeS/WAN distribution.
+<p>
+Since 1.8, we have begun to rely on the system copy of GMP.
+</p>
+
+</body>
+</html>
+
diff --git a/doc/src/testing.html b/doc/src/testing.html
new file mode 100644
index 000000000..8ffcca604
--- /dev/null
+++ b/doc/src/testing.html
@@ -0,0 +1,395 @@
+<html>
+<head>
+<title>Testing FreeS/WAN</title>
+
+<meta name="keywords" content="Linux, IPsec, VPN, security, FreeSWAN, testing">
+
+<!--
+
+Written by Sandy Harris for the Linux FreeS/WAN project
+Freely distributable under the GNU General Public License
+
+More information at www.freeswan.org
+Feedback to users@lists.freeswan.org
+
+CVS information:
+RCS ID:          $Id: testing.html,v 1.1 2004/03/15 20:35:24 as Exp $
+Last changed:    $Date: 2004/03/15 20:35:24 $
+Revision number: $Revision: 1.1 $
+
+CVS revision numbers do not correspond to FreeS/WAN release numbers.
+-->
+</head>
+
+<body>
+<h1><a name="test.freeswan">Testing FreeS/WAN</a></h1>
+This document discusses testing FreeS/WAN.
+
+<p>Not all types of testing are described here. Other parts of the
+documentation describe some tests:</p>
+<dl>
+  <dt><a href="install.html#testinstall">installation</a> document</dt>
+    <dd>testing for a successful install</dd>
+  <dt><a href="config.html#testsetup">configuration</a> document</dt>
+    <dd>basic tests for a working configuration</dd>
+  <dt><a href="web.html#interop.web">web links</a> document</dt>
+    <dd>General information on tests for interoperability between various
+      IPsec implementations. This includes links to several test sites.</dd>
+  <dt><a href="interop.html">interoperation</a> document.</dt>
+    <dd>More specific information on FreeS/WAN interoperation with other
+      implementations.</dd>
+  <dt><a href="performance.html">performance</a> document</dt>
+    <dd>performance measurements</dd>
+</dl>
+
+<p>The test setups and procedures described here can also be used in other
+testing, but this document focuses on testing the IPsec functionality of
+FreeS/WAN.</p>
+
+<H2><A NAME="test.oe">Testing opportunistic connections</A></H2>
+
+<P>This section teaches you how to test your opportunistically encrypted (OE)
+connections. To set up OE, please see the easy instructions in our
+<A HREF="quickstart.html">quickstart guide</A>.</P>
+
+<H3>Basic OE Test</H3>
+
+
+<P>This test is for basic OE functionality. 
+<!-- You may use it on an 
+<A HREF="quickstart.html#oppo.client">initiate-only OE</A> box or a 
+<A HREF="quickstart.html#opp.incoming">full OE</A> box. -->
+For additional tests, keep reading.</P>
+
+<P>Be sure IPsec is running. You can see whether it is with:</P>
+<PRE>    ipsec setup status</PRE>
+<P>If need be, you can restart it with:</P>
+<PRE>    service ipsec restart</PRE>
+                                                                                
+<P>Load a FreeS/WAN test website from the host on which you're running
+FreeS/WAN. Note: the feds may be watching these sites. Type one of:<P>
+<PRE>   links oetest.freeswan.org</PRE>
+<PRE>   links oetest.freeswan.nl</PRE>
+<!--<PRE>   links oetest.freeswan.ca</PRE>-->
+                                                                                
+<P>A positive result looks like this:</P>
+                                                                                
+<PRE>
+   You  seem  to  be  connecting  from:  192.0.2.11 which DNS says is:
+   gateway.example.com
+     _________________________________________________________________
+                                                                                
+   Status E-route
+   OE    enabled    16    192.139.46.73/32    ->    192.0.2.11/32   =>
+   tun0x2097@192.0.2.11
+   OE    enabled    176    192.139.46.77/32    ->   192.0.2.11/32   =>
+   tun0x208a@192.0.2.11
+</PRE>
+                                                                                
+<P>If you see this, congratulations! Your OE box will now encrypt
+its own traffic whenever it can. If you have difficulty,
+see our <A HREF="#oe.trouble">OE troubleshooting tips</A>.
+</P>
+
+<H3>OE Gateway Test</H3>                                                                                
+<P>If you've set up FreeS/WAN to protect a subnet behind your gateway,
+you'll need to run another simple test, which can be done from a machine
+running any OS. That's right, your Windows box can be protected by
+opportunistic encryption without any FreeS/WAN install or configuration
+on that box. From <STRONG>each protected subnet node</STRONG>,
+load the FreeS/WAN website with:</P>
+                                                                                
+<PRE>   links oetest.freeswan.org</PRE>
+<PRE>   links oetest.freeswan.nl</PRE>
+                                                                                
+<P>A positive result looks like this:</P>
+<PRE>
+   You  seem  to  be  connecting  from:  192.0.2.98 which DNS says is:
+   box98.example.com
+     _________________________________________________________________
+                                                                                
+   Status E-route
+   OE    enabled    16    192.139.46.73/32    ->    192.0.2.98/32   =>
+   tun0x134ed@192.0.2.11
+   OE    enabled    176    192.139.46.77/32    ->   192.0.2.11/32   =>
+   tun0x134d2@192.0.2.11
+</PRE>
+                                                                                
+<P>If you see this, congratulations! Your OE gateway will now encrypt
+traffic for this subnet node whenever it can. If you have difficulty, see our
+<A HREF="#oe.trouble">OE troubleshooting tips</A>.
+</P>
+                                                                                
+                                                                                
+<H3>Additional OE tests</H3>
+                                                                                
+<P>When testing OE, you will often find it useful to execute this command
+on the FreeS/WAN host:</P>
+<PRE>   ipsec eroute</PRE>
+                                                                                
+<P>If you have established a connection (either for or for a subnet node)
+you will see a result like:</P>
+                                                                                
+<PRE>    192.0.2.11/32   -> 192.139.46.73/32  => tun0x149f@192.139.46.38
+</PRE>
+                                                                                
+<P>Key:</P>
+<TABLE>
+<TR><TD>1.</TD>
+    <TD>192.0.2.11/32</TD>
+    <TD>Local start point of the protected traffic.
+    </TD></TR>
+<TR><TD>2.</TD>
+    <TD>192.0.2.194/32</TD>
+    <TD>Remote end point of the protected traffic.
+    </TD></TR>
+<TR><TD>3.</TD>
+    <TD>192.0.48.38</TD>
+    <TD>Remote FreeS/WAN node (gateway or host).
+        May be the same as (2).
+   </TD></TR>
+<TR><TD>4.</TD>
+    <TD>[not shown]</TD>
+    <TD>Local FreeS/WAN node (gateway or host), where you've produced the output.
+        May be the same as (1).
+   </TD></TR>
+</TABLE>
+                                                                                
+                                                                                
+<P>For extra assurance, you may wish to use a packet sniffer such as
+<A HREF="http://www.tcpdump.org">tcpdump</A> to verify that packets
+are being encrypted. You should see output that indicates
+<STRONG>ESP</STRONG> encrypted data,
+ for example:</P>
+                                                                                
+<PRE>    02:17:47.353750 PPPoE  [ses 0x1e12] IP 154: xy.example.com > oetest.freeswan.org: ESP(spi=0x87150d16,seq=0x55)</PRE>
+                                                                                
+
+
+<h2><a name="test.uml">Testing with User Mode Linux</a></h2>
+
+<p><a href="http://user-mode-linux.sourceforge.net/">User Mode Linux</a>
+allows you to run Linux as a user process on another Linux machine.</p>
+
+<p>As of 1.92, the distribution has a new directory named  testing. It
+contains a collection of test scripts and sample configurations. Using these,
+you can bring up several copies of Linux in user mode and have them build
+tunnels to each other. This lets you do some testing of  a FreeS/WAN
+configuration on a single machine.</p>
+
+<p>You need a moderately well-endowed machine for this to work well. Each UML
+wants about 16 megs of memory by default, which is plenty for FreeS/WAN
+usage. Typical regression testing only occasionally uses as many as 4 UMLs.
+If one is doing nothing else with the machine (in particular, not running X
+on it), then 128 megs and a 500MHz CPU are fine.</p>
+
+Documentation on these
+scripts is <a href="umltesting.html">here</a>. There is also documentation 
+on automated testing <A href="makecheck.html">here</a>.
+ 
+<h2><a name="testnet">Configuration for a testbed network</a></h2>
+
+<p>A common test setup is to put a machine with dual Ethernet cards in
+between two gateways under test. You need at least five machines; two
+gateways, two clients and a testing machine in the middle.</p>
+
+<p>The central machine both routes packets and provides a place to run
+diagnostic software for checking IPsec packets. See next section for
+discussion of <a href="#tcpdump.faq">using tcpdump(8)</a> for this.</p>
+
+<p>This makes things more complicated than if you just connected the two
+gateway machines directly to each other, but it also makes your test setup
+much more like the environment you actually use IPsec in. Those environments
+nearly always involve routing, and quite a few apparent IPsec failures turn
+out to be problems with routing or with firewalls dropping packets. This
+approach lets you deal with those problems on your test setup.</p>
+
+<p>What you end up with looks like:</p>
+
+<h3><a name="testbed">Testbed network</a></h3>
+<pre>      subnet a.b.c.0/24
+             |
+      eth1 = a.b.c.1
+         gate1
+      eth0 = 192.168.p.1
+             |
+             |
+      eth0 = 192.168.p.2
+         route/monitor box
+      eth1 = 192.168.q.2
+             |
+             |
+      eth0 = 192.168.q.1
+         gate2
+      eth1 = x.y.z.1
+              |
+       subnet x.y.z.0/24</pre>
+<pre>Where p and q are any convenient values that do not interfere with other
+routes you may have. The ipsec.conf(5) file then has, among other things:</pre>
+<pre>conn abc-xyz
+      left=192.168.p.1
+      leftnexthop=192.168.p.2
+      right=192.168.q.1
+      rightnexthop=192.168.q.2</pre>
+
+<p>Once that works, you can remove the "route/monitor box", and connect the
+two gateways to the Internet. The only parameters in ipsec.conf(5) that need
+to change are the four shown above. You replace them with values appropriate
+for your Internet connection, and change the eth0 IP addresses and the
+default routes on both gateways.</p>
+
+<p>Note that nothing on either subnet needs to change. This lets you test
+most of your IPsec setup before connecting to the insecure Internet.</p>
+
+<h3><a name="tcpdump.test">Using packet sniffers in testing</a></h3>
+
+<p>A number of tools are available for looking at packets. We will discuss
+using <a href="http://www.tcpdump.org/">tcpdump(8)</a>, a common Linux tool
+included in most distributions. Alternatives offerring more-or-less the same
+functionality include:</p>
+<dl>
+  <dt><a href="http://www.ethereal.com">Ethereal</a></dt>
+    <dd>Several people on our mailing list report a preference for this over
+      tcpdump.</dd>
+  <dt><a href="http://netgroup-serv.polito.it/windump/">windump</a></dt>
+    <dd>a Windows version of tcpdump(8), possibly handy if you have Windows
+      boxes in your network</dd>
+  <dt><a
+  href="http://reptile.rug.ac.be/~coder/sniffit/sniffit.html">Sniffit</a></dt>
+    <dd>A linux sniffer that we don't know much about. If you use it, please
+      comment on our mailing list.</dd>
+</dl>
+
+<p>See also this <a
+href="http://www.tlsecurity.net/unix/ids/sniffer/">index</a> of packet
+sniffers.</p>
+
+<p>tcpdump(8) may misbehave if run on the gateways themselves. It is designed
+to look into a normal IP stack and may become confused if you ask it to
+display data from a stack which has IPsec in play.</p>
+
+<p>At one point, the problem was quite severe. Recent versions of tcpdump,
+however, understand IPsec well enough to be usable on a gateway. You can get
+the latest version from <a href="http://www.tcpdump.org/">tcpdump.org</a>.</p>
+
+<p>Even with a recent tcpdump, some care is required. Here is part of a post
+from Henry on the topic:</p>
+<pre>&gt; a) data from sunset to sunrise or the other way is not being
+&gt; encrypted (I am using tcpdump (ver. 3.4) -x/ping -p to check
+&gt; packages) 
+
+What *interface* is tcpdump being applied to?  Use the -i option to
+control this.  It matters!  If tcpdump is looking at the ipsecN
+interfaces, e.g. ipsec0, then it is seeing the packets before they are
+encrypted or after they are decrypted, so of course they don't look
+encrypted.  You want to have tcpdump looking at the actual hardware
+interfaces, e.g. eth0. 
+
+Actually, the only way to be *sure* what you are sending on the wire is to
+have a separate machine eavesdropping on the traffic.  Nothing you can do
+on the machines actually running IPsec is 100% guaranteed reliable in this
+area (although tcpdump is a lot better now than it used to be).</pre>
+
+<p>The most certain way to examine IPsec packets is to look at them on the
+wire. For security, you need to be certain, so we recommend doing that. To do
+so, you need a <strong>separate sniffer machine located between the two
+gateways</strong>. This machine can be routing IPsec packets, but it must not
+be an IPsec gateway. Network configuration for such testing is discussed <a
+href="#testnet">above</a>.</p>
+
+<p>Here's another mailing list message with advice on using tcpdump(8):</p>
+<pre>Subject: RE: [Users] Encrypted???
+   Date: Thu, 29 Nov 2001
+   From: "Joe Patterson" &lt;jpatterson@asgardgroup.com&gt;
+
+tcpdump -nl -i $EXT-IF proto 50
+
+-nl tells it not to buffer output or resolve names (if you don't do that it
+may confuse you by not outputing anything for a while), -i $EXT-IF (replace
+with your external interface) tells it what interface to listen on, and
+proto 50 is ESP.  Use "proto 51" if for some odd reason you're using AH, and
+"udp port 500" if you want to see the isakmp key exchange/tunnel setup
+packets.
+
+You can also run `tcpdump -nl -i ipsec0` to see what traffic is on that
+virtual interface.  Anything you see there *should* be either encrypted or
+dropped (unless you've turned on some strange options in your ipsec.conf
+file)
+
+Another very handy thing is ethereal (http://www.ethereal.com/) which runs
+on just about anything, has a nice gui interface (or a nice text-based
+interface), and does a great job of protocol  breakdown.  For ESP and AH
+it'll basically just tell you that there's a packet of that protocol, and
+what the spi is, but for isakmp it'll actually show you a lot of the tunnel
+setup information (until it gets to the point in the protocol where isakmp
+is encrypted....)</pre>
+
+<h2><a name="verify.crypt">Verifying encryption</a></h2>
+
+<p>The question of how to verify that messages are actually encrypted has
+been extensively discussed on the mailing list. See this <a
+href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/07/msg00262.html">thread</a>.</p>
+
+<p>If you just want to verify that packets are encrypted, look at them with a
+packet sniffer (see <a href="#tcpdump.test">previous section</a>) located
+between the gateways. The packets should, except for some of the header
+information, be utterly unintelligible. <strong>The output of good encryption
+looks <em>exactly</em> like random noise</strong>. </p>
+
+<p>A packet sniffer can only tell you that the data you looked at was
+encrypted. If you have stronger requirements -- for example if your security
+policy requires verification that plaintext is not leaked during startup or
+under various anomolous conditions -- then you will need to devise much more
+thorough tests. If you do that, please post any results or methodological
+details which your security policy allows you to make public.</p>
+
+<p>You can put recognizable data into ping packets with something like:</p>
+<pre>        ping -p feedfacedeadbeef 11.0.1.1</pre>
+
+<p>"feedfacedeadbeef" is a legal hexadecimal pattern that is easy to pick out
+of hex dumps.</p>
+
+<p>For other protocols, you may need to check if you have encrypted data or
+ASCII text. Encrypted data has approximately equal frequencies for all 256
+possible characters. ASCII text has most characters in the printable range
+0x20-0x7f, a few control characters less than 0x20, and none at all in the
+range 0x80-0xff. 0x20, space, is a good character to look for. In normal
+English text space occurs about once in seven characters, versus about once
+in 256 for random or encrypted data.</p>
+
+<p>One thing to watch for: the output of good compression, like that of good
+encryption, looks just like random noise. You cannot tell just by looking at
+a data stream whether it has been compressed, encrypted, or both. You need a
+little care not to mistake compressed data for encrypted data in your
+testing.</p>
+
+<p>Note also that weak encryption also produces random-looking output. You
+cannot tell whether the encryption is strong by looking at the output. To be
+sure of that, you would need to have both the algorithms and the
+implementation examined by experts. </p>
+
+<p>For IPsec, you can get partial assurance from interoperability tests. See
+our <a href="interop.html">interop</a> document. When twenty products all
+claim to implement <a href="glossary.html#3DES">3DES</a>, and they all talk
+to each other, you can be fairly sure they have it right. Of course, you
+might wonder whether all the implementers are consipring to trick you or,
+more plausibly, whether some implementations might have "back doors" so they
+can get also it wrong when required.. If you're seriously worried about
+things like that, you need to get the code you use audited (good luck if it
+is not Open Source), or perhaps to talk to a psychiatrist about treatments
+for paranoia. </p>
+
+<h2><a name="mail.test">Mailing list pointers</a></h2>
+
+<p>Additional information on testing can be found in these <a
+href="mail.html">mailing list</a> messages:</p>
+<ul>
+  <li>a user's detailed <a
+    href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/11/msg00571.html">setup
+    diary</a> for his testbed network</li>
+  <li>a FreeS/WAN team member's <a
+    href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/11/msg00425.html">notes</a>
+    from testing at an IPsec interop "bakeoff"</li>
+</ul>
+</body>
+</html>
diff --git a/doc/src/testingtools.html b/doc/src/testingtools.html
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+++ b/doc/src/testingtools.html
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+<html>
+<head>
+<title>FreeS/WAN survey of testing tools</title>
+<!-- Changed by: Michael Richardson, 02-Jan-2002 -->
+<meta name="keywords" content="Linux, IPsec, VPN, security, FreeSWAN, testing, nettools">
+
+<!--
+
+Written by Michael Richardson for the Linux FreeS/WAN project
+Freely distributable under the GNU General Public License
+
+More information at www.freeswan.org
+Feedback to users@lists.freeswan.org
+
+$Id: testingtools.html,v 1.1 2004/03/15 20:35:24 as Exp $
+
+$Log: testingtools.html,v $
+Revision 1.1  2004/03/15 20:35:24  as
+added files from freeswan-2.04-x509-1.5.3
+
+Revision 1.1  2002/03/12 20:57:25  mcr
+	review of tools used for testing FreeSWAN systems.
+
+
+-->
+</head>
+
+<body>
+
+<h1>Survey of testing tools</h1>
+
+<h2><A HREF="http://freshmeat.net/projects/apsend">http://freshmeat.net/projects/apsend</A></h2>
+
+<P>
+About: <A HREF="">APSEND</A> is a TCP/IP packet sender to test firewalls and other
+network applications. It also includes a syn flood option, the land
+DoS attack, a DoS attack against tcpdump running on a UNIX-based
+system, a UDP-flood attack, and a ping flood option. It currently
+supports the following protocols: IP, TCP, UDP, ICMP, Ethernet frames
+and you can also build any other type of protocol using the generic
+option. The scripting language of apsend is already written, but not
+yet public.   
+</P>
+
+<P>
+STATUS: The public web site seems to have died
+</P>
+
+<h2><A HREF="http://freshmeat.net/projects/hping2">http://freshmeat.net/projects/hping2</A></h2>
+
+<P>
+About: <A HREF="http://www.hping.org/">hping2</A> is a network tool
+able to send custom ICMP/UDP/TCP packets and to display target replies
+like ping does with ICMP replies. It handles fragmentation and
+arbitrary packet body and size, and can be used to transfer files
+under supported protocols. Using hping2, you can: test firewall rules,
+perform [spoofed] port scanning, test net performance using different
+protocols, packet size, TOS (type of service), and fragmentation, do
+path MTU discovery, tranfer files (even between really Fascist
+firewall rules), perform traceroute-like actions under different
+protocols, fingerprint remote OSs, audit a TCP/IP stack, etc. hping2
+is a good tool for learning TCP/IP.  
+</P>
+
+<P>
+This utility has rather complicated usage and no man page at present. 
+The documentation is supposed to be in HPING2-HOWTO, but that file
+seems to be absent. 
+</P>
+
+<h2><A HREF="http://freshmeat.net/projects/icmpush">http://freshmeat.net/projects/icmpush</A></h2>
+
+<P>
+About: ICMPush is a tool that send ICMP packets fully customized from command
+line. This release supports the ICMP error types Unreach, Parameter
+Problem, Redirect and Source Quench and the ICMP information types
+Timestamp, Address Mask Request, Information Request, Router
+Solicitation, Router Advertisement and Echo Request. Also supports
+ip-spoofing, broadcasting and other useful features. It's really a
+powerful program for testing and debugging TCP/IP stacks and networks.
+</P>
+
+<P>
+</P>
+
+<h2><A HREF="http://freshmeat.net/projects/isic">http://freshmeat.net/projects/isic</A></h2>
+
+<P>
+ISIC sends randomly generated packets to a target computer. Its
+primary uses are to stress-test an IP stack, to find leaks in a
+firewall, and to test the implementation of IDSes and firewalls. The
+user can specify how often the packets will be frags, have IP options,
+TCP options, an urgent pointer, etc. Programs for TCP, UDP, ICMP,
+IP w/ random protocols, and random ethernet frames are included.  
+</P>
+
+<h2><A HREF="http://freshmeat.net/projects/sendpacket">http://freshmeat.net/projects/sendpacket</A></h2>
+
+<P>
+Send Packet is a small but powerful program to test how your network
+responds to specific packet content. Via a config file and/or command
+line parameters, you can forge (modify the headers of) your own
+TCP/UDP/ICMP/IP packets and send them through your network. Also,
+following the Easy Sniffer modular philosophy, you can specify wich
+modules you'd like to build.  
+</P>
+
+<h2><A HREF="http://freshmeat.net/projects/aicmpsend/">http://freshmeat.net/projects/aicmpsend/</A></h2>
+
+<P>
+AICMPSEND is an ICMP sender with many features including ICMP
+flooding and spoofing. All ICMP flags and codes are implemented. You
+can use this program for various DoS attacks, for ICMP flooding and
+to test firewalls.  
+</P>
+
+<h2><A HREF="http://freshmeat.net/projects/sendip/">http://freshmeat.net/projects/sendip/</A></h2>
+
+<P>
+SendIP is a command-line tool to send arbitrary IP packets. It has a
+large number of options to specify the content of every header of a
+RIP, TCP, UDP, ICMP, or raw IPv4/IPv6 packet. It also allows any data
+to be added to the packet. Checksums can be calculated automatically,
+but if you wish to send out wrong checksums, that is supported too.  
+</P>
+
+<h2><A HREF="http://laurent.riesterer.free.fr/gasp/index.html">http://laurent.riesterer.free.fr/gasp/index.html</A></h2>
+
+<P>
+GASP stands for 'Generator and Analyzer System for Protocols'. It
+allows you to decode and encode any protocols you specify.  
+</P>
+
+<P>
+The main use is probably to test networks applications : you can
+construct packets by hand and test the behavior of your program when
+facing some strange packets. But you can image a lot of other
+application : e.g. manipulating graphical file or executable
+headers. Just describe the specification of the structured data.  
+</P>
+
+<P>
+GASP is divided in two parts : a compiler which take the specification
+of the protocols and generate the code to handle it, this code is a
+new Tcl command as GASP in build upon Tcl/Tk and extends the scripting
+facilities provided by Tcl. 
+</P>
+
+<h2><A HREF="http://pdump.lucidx.com/">http://pdump.lucidx.com/</A></h2>
+<h2><A HREF="http://freshmeat.net/projects/aps/">http://freshmeat.net/projects/aps/</A></h2>
+<h2><A HREF="http://freshmeat.net/projects/netsed/">http://freshmeat.net/projects/netsed/</A></h2>
+<h2><A HREF="http://www.via.ecp.fr/~bbp/netsh/">http://www.via.ecp.fr/~bbp/netsh/</A></h2>
+<h2><A HREF="http://www.elxsi.de/">http://www.elxsi.de/</A></h2>
+<h2><A HREF="http://www.laurentconstantin.com/us/lcrzo/">http://www.laurentconstantin.com/us/lcrzo/</A></h2>
+<h2><A HREF="http://www.joedog.org/libping/index.html">http://www.joedog.org/libping/index.html</A></h2>
+<h2><A HREF="http://feynman.mme.wilkes.edu/projects/xNetTools/">http://feynman.mme.wilkes.edu/projects/xNetTools/</A></h2>
+<h2><A HREF="http://freshmeat.net/projects/pktsrc/">http://freshmeat.net/projects/pktsrc/</A></h2>
+<h2><A HREF="http://freshmeat.net/projects/lcrzoex/">http://freshmeat.net/projects/lcrzoex/</A></h2>
+<h2><A HREF="http://freshmeat.net/projects/rain/">http://freshmeat.net/projects/rain/</A></h2>
+<P>
+rain is a powerful packet builder for testing the stability of
+hardware and software. Its features include support for all IP
+protocols and the ability to fully customize the packets it sends.  
+</P>
+
+<P>(Note, this is not the same as /usr/games/rain)</P>
+
+<h2><A HREF="http://freshmeat.net/projects/libnet">http://freshmeat.net/projects/libnet</A></h2>
+<h2><A HREF="http://freshmeat.net/projects/pftp">http://freshmeat.net/projects/pftp</A></h2>
+<h2><A HREF="http://freshmeat.net/projects/pung">http://freshmeat.net/projects/pung</A></h2>
+
+<P>
+pung is a simple server tester. It tries to connect via TCP/IP to a
+server but does not transfer any data. It is meant to be used in
+scripts that check a list of servers, helping to detect certain common
+problems.  
+</P>
+
+<h2><A HREF="http://freshmeat.net/projects/thesunpacketshell">http://freshmeat.net/projects/thesunpacketshell</A></h2>
+<h2><A HREF="http://freshmeat.net/projects/webperformancetrainer">http://freshmeat.net/projects/webperformancetrainer</A></h2>
+<h2><A HREF="http://sourceforge.net/projects/va-ctcs">http://sourceforge.net/projects/va-ctcs</A></h2>
+<h2><A HREF="http://synscan.nss.nu/programs.php">http://synscan.nss.nu/programs.php</A></h2>
+<h2><A HREF="http://sourceforge.net/projects/va-ctcs">http://sourceforge.net/projects/va-ctcs</A></h2>
+<h2><A HREF="http://freshmeat.net/projects/ettercap/">http://freshmeat.net/projects/ettercap/</A></h2>
+<h2><A HREF="http://www.dtek.chalmers.se/~d3august/xt/index.html">http://www.dtek.chalmers.se/~d3august/xt/index.html</A></h2>
+<h2><A HREF="http://www.opersys.com/LTT/">http://www.opersys.com/LTT/</A></h2>
+<h2><A HREF="http://packetstorm.securify.com/DoS/indexdate.shtml">http://packetstorm.securify.com/DoS/indexdate.shtml</A></h2>
+<H2> <A HREF="http://comnet.technion.ac.il/~cn1w02/">TCP/IP noise simulator</A></H2>
diff --git a/doc/src/trouble.html b/doc/src/trouble.html
new file mode 100644
index 000000000..604264c01
--- /dev/null
+++ b/doc/src/trouble.html
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+<HTML>
+<HEAD>
+	<TITLE>FreeS/WAN troubleshooting</TITLE>
+      <meta name="keywords" content="Linux, IPSEC, VPN, security, FreeSWAN, troubleshooting, debugging">
+<!--
+     Written by Claudia Schmeing for the Linux FreeS/WAN project
+     Freely distributable under the GNU General Public License
+
+     More information at www.freeswan.org
+     Feedback to users@lists.freeswan.org
+
+CVS information:
+RCS ID:          $Id: trouble.html,v 1.1 2004/03/15 20:35:24 as Exp $
+Last changed:    $Date: 2004/03/15 20:35:24 $
+Revision number: $Revision: 1.1 $
+
+CVS revision numbers do not correspond to FreeS/WAN release numbers.
+-->
+ 
+</HEAD>
+<BODY>
+
+<H1><A NAME="trouble"></A>Linux FreeS/WAN Troubleshooting Guide</H1>
+
+<H2><A NAME="overview"></A>Overview</H2>
+
+<P>
+This document covers several general places where you might have a problem:</P>
+<OL>
+	<LI><A HREF="#install">During install</A>.</LI>
+	<LI><A HREF="#negotiation">During the negotiation process</A>.</LI>
+	<LI><A HREF="#use">Using an established connection</A>.</LI>
+</OL>
+<P>This document also contains <A HREF="#notes">notes</A> which
+expand on points made in these sections, and tips for 
+<A HREF="#prob.report">problem
+reporting</A>. If the other end of your connection is not FreeS/WAN,
+you'll also want to read our 
+<A HREF="interop.html#interop.problem">interoperation</A> document.</P>
+<H2><A NAME="install"></A>1. During Install</H2>
+<H3>1.1 RPM install gotchas</H3>
+<P>With the RPM method:</P>
+<UL>
+<LI>Be sure you have installed both the userland tools and the kernel
+  components. One will not work without the other. For example, when using 
+  FreeS/WAN-produced RPMs for our 2.04 release, you need both:
+<PRE>    freeswan-userland-2.04_2.4.20_20.9-0.i386.rpm
+    freeswan-module-2.04_2.4.20_20.9-0.i386.rpm
+</PRE>
+</LI>
+</UL>
+<H3>1.2 Problems installing from source</H3>
+<P>When installing from source, you may find these problems:</P>
+<UL>
+	<LI>Missing library. See <A HREF="faq.html#gmp.h_missing">this</A>
+	FAQ.</LI>
+	<LI>Missing utilities required for compile. See this 
+        <A HREF="install.html#tool.lib">checklist</A>.</LI>
+	<LI>Kernel version incompatibility. See <A HREF="faq.html#k.versions">this</A>
+	FAQ.</LI>
+	<LI>Another compile problem. Find information in the out.* files,
+	ie. out.kpatch, out.kbuild, created at compile time in the top-level
+	Linux FreeS/WAN directory. Error messages generated by KLIPS during
+	the boot sequence are accessible with the <VAR>dmesg</VAR> command. 
+	<BR>
+	Check the list archives and the List in Brief to see if this is a
+	known issue. If it is not, report it to the bugs list as described
+	in our <A HREF="#prob.report">problem reporting</A> section. In some
+	cases, you may be asked to provide debugging information using gdb;
+	details <A HREF="#gdb">below</A>.</LI>
+	<LI>If your kernel compiles but you fail to install your new
+	FreeS/WAN-enabled kernel, review the sections on <A HREF="install.html#newk">installing
+	the patched kernel</A>, and <A HREF="install.html#testinstall">testing</A>
+	to see if install succeeded.</LI>
+</UL>
+<H3><A NAME="install.check"></A>1.3 Install checks</H3>
+<P><VAR>ipsec verify</VAR> checks a number 
+of FreeS/WAN essentials. Here are some hints on what do to when your
+system doesn't check out:</P>
+<P>
+<TABLE border=1>
+<TR>
+<TD><STRONG>Problem</STRONG></TD>
+<TD><STRONG>Status</STRONG></TD>
+<TD><STRONG>Action</STRONG></TD>
+</TR>
+<TR>
+<TD><VAR>ipsec</VAR> not on-path</TD>
+<TD>&nbsp;</TD>
+<TD><P>Add <VAR>/usr/local/sbin</VAR> to your PATH.</P></TD>
+</TR>
+<TR>
+<TD>Missing KLIPS support</TD>
+<TD><FONT COLOR="#FF0000">critical</FONT></TD>
+<TD>See <A HREF="faq.html#noKLIPS">this FAQ.</A></TD>
+</TR>
+<TR>
+<TD>No RSA private key</TD>
+<TD>&nbsp;</TD>
+<TD>
+<P>Follow <A HREF="install.html#genrsakey">these 
+instructions</A> to create an RSA key pair for your host. RSA keys are:</P>
+<UL>
+<LI>required for opportunistic encryption, and</LI>
+<LI>our preferred method to authenticate pre-configured connections.</LI>
+</UL>
+</TD>
+</TR>
+<TR>
+<TD><VAR>pluto</VAR> not running</TD>
+<TD><FONT COLOR="#FF0000">critical</FONT></TD>
+<TD><PRE>service ipsec start</PRE></TD>
+</TR>
+<TR>
+<TD>No port 500 hole</TD>
+<TD><FONT COLOR="#FF0000">critical</FONT></TD>
+<TD>Open port 500 for IKE negotiation.</TD>
+</TR>
+<TR>
+<TD>Port 500 check N/A</TD>
+<TD>&nbsp;</TD>
+<TD>Check that port 500 is open for IKE negotiation.</TD>
+</TR>
+<TR>
+<TD>Failed DNS checks</TD>
+<TD>&nbsp;</TD>
+<TD>Opportunistic encryption requires information from DNS.
+To set this up, see <A HREF="quickstart.html#opp.setup">our instructions</A>.
+</TD>
+</TR>
+<TR>
+<TD>No public IP address</TD>
+<TD>&nbsp;</TD>
+<TD>Check that the interface which you want to protect with IPSec is up and 
+running.</TD>
+</TR>
+</TABLE>
+
+
+<H3><A NAME="oe.trouble"></A>1.3 Troubleshooting OE</H3>
+<P>OE should work with no local configuration, if you have posted
+DNS TXT records according to the instructions in our 
+<A HREF="quickstart.html">quickstart guide</A>.
+If you encounter trouble, try these hints. 
+We welcome additional hints via the
+<A HREF="mail.html">users' mailing list</A>.</P>
+                                                                                
+<TABLE border=1>
+<TR>
+<TD><STRONG>Symptom</STRONG></TD>
+<TD><STRONG>Problem</STRONG></TD>
+<TD><STRONG>Action</STRONG></TD>
+</TR>
+<TR>
+<TD>
+You're running FreeS/WAN 2.01 (or later),
+and initiating a connection to FreeS/WAN
+2.00 (or earlier).
+In your logs, you see a message like:
+<pre>no RSA public key known for '192.0.2.13';
+DNS search for KEY failed (no KEY record
+for 13.2.0.192.in-addr.arpa.)</pre>
+The older FreeS/WAN logs no error.
+</TD>
+<TD>
+<A NAME="oe.trouble.flagday"></A>
+A protocol level incompatibility between 2.01 (or later) and
+2.00 (or earlier) causes this error. It occurs when a FreeS/WAN 2.01
+(or later) box for which no KEY record is posted attempts to initiate an OE
+connection to older FreeS/WAN versions (2.00 and earlier).
+Note that older versions can initiate to newer versions without this error.
+</TD>
+<TD>If you control the peer host, upgrade its FreeS/WAN to 2.01 (or later), and
+post new style TXT records for it. If not, but if you know its sysadmin,
+perhaps a quick note is in order. If neither option is possible, you can
+ease the transition by posting an old style KEY record (created with a
+command like "ipsec&nbsp;showhostkey&nbsp;--key") to the reverse map for
+the FreeS/WAN 2.01 (or later) box.</TD>
+</TR>
+<TR>
+<TD>OE host is very slow to contact other hosts.</TD>
+<TD>Slow DNS service while running OE.</TD>
+<TD>It's a good idea to run a caching DNS server on your OE host,
+as outlined in <A HREF="http://lists.freeswan.org/pipermail/design/2003-January/004205.html">this
+mailing list message</A>. If your DNS servers are elsewhere,
+put their IPs
+in the <VAR>clear</VAR> policy group, and
+re-read groups with <PRE>ipsec auto --rereadgroups</PRE>
+</TD>
+</TR>
+<TR>
+<TD>
+<PRE>Can't Opportunistically initiate for
+192.0.2.2 to 192.0.2.3: no TXT record
+for 13.2.0.192.in-addr.arpa.</PRE>
+</TD>
+<TD>Peer is not set up for OE.</TD>
+<TD><P>None. Plenty of hosts on the Internet
+do not run OE. If, however, you have set OE up on that peer, this may
+indicate that you need to wait up to 48 hours
+for its DNS records to propagate.</P></TD>
+</TR>
+<TR>
+<TD><VAR>ipsec verify</VAR> does not find DNS records:
+<PRE>...
+Looking for TXT in forward map:
+                xy.example.com...[FAILED]
+Looking for TXT in reverse map...[FAILED]
+...</PRE>
+                                                                                
+You also experience authentication failure:<BR>
+<PRE>Possible authentication failure:
+no acceptable response to our
+first encrypted message</PRE>
+</TD>
+                                                                                
+<TD>DNS records are not posted or have not propagated.</TD>
+<TD>Did you post the DNS records necessary for OE? If not,
+do so using the instructions in our
+<A HREF="quickstart.html#quickstart">quickstart guide</A>.
+If so, wait up to 48 hours for the DNS records to propagate.</TD>
+</TR>
+<TR>
+<TD><VAR>ipsec verify</VAR> does not find DNS records, and you experience
+authentication failure.</TD>
+<TD>For iOE, your ID
+does not match location of
+forward DNS record.</TD>
+<TD>In <VAR>config setup</VAR>, change
+<VAR>myid=</VAR> to match the forward DNS where you posted the record.
+Restart FreeS/WAN.
+ For reference, see our
+<A HREF="quickstart.html#opp.client">iOE instructions</A>.</TD>
+</TR>
+<TR>
+<TD><VAR>ipsec verify</VAR> finds DNS records, yet there is
+still authentication failure. ( ? )</TD>
+<TD>DNS records are malformed.</TD>
+<TD>Re-create the records and send new copies to your DNS administrator.</TD>
+</TR>
+<TR>
+<TD><VAR>ipsec verify</VAR> finds DNS records, yet there is
+still authentication failure. ( ? )</TD>
+<TD>DNS records show different keys for a gateway vs. its subnet hosts.</TD>
+<TD>All TXT records for boxes protected by an OE gateway must contain the
+gateway's public key. Re-create and re-post any incorrect records using
+<A HREF="quickstart.html#opp.incoming">these instructions</A>.</TD>
+</TR>
+<TR>
+<TD>OE gateway loses connectivity to its subnet. The gateway's
+routing table shows routes to the subnet through IPsec interfaces.</TD>
+<TD>The subnet is part of the <VAR>private</VAR> or <VAR>block</VAR>
+policy group on the gateway.</TD>
+<TD>Remove the subnet from the group, and reread
+groups with <PRE>ipsec auto --rereadgroups</PRE></TD>
+</TR>
+<TR>
+<TD>OE does not work to hosts on the local LAN.</TD>
+<TD>This is a known issue.</TD>
+<TD>See <A HREF="opportunism.known-issues">this list</A> of known issues
+with OE.
+</TD>
+</TR>
+                                                                                
+<TR>
+<TD>FreeS/WAN does not seem to be executing your default policy. In your
+logs, you see a message like:
+<PRE>/etc/ipsec.d/policies/iprivate-or-clear"
+line 14: subnet "0.0.0.0/0",
+source 192.0.2.13/32,
+already "private-or-clear"</PRE>
+</TD>
+<TD><A HREF="glossary.html#fullnet">Fullnet</A> in a policy group file defines
+your default policy. Fullnet should normally be present in only one policy
+group file. The fine print: you can have two default policies defined so long
+as they protect different local endpoints (e.g. the FreeS/WAN gateway and a
+subnet).</TD>
+<TD>
+Find all policies which contain fullnet with:<br>
+<PRE>grep -F 0.0.0.0/0 /etc/ipsec.d/policies/*</PRE>
+then remove the unwanted occurrence(s).
+</TD>
+</TR>
+                                                                                
+</TABLE>
+
+
+<H2><A NAME="negotiation"></A>2. During Negotiation</H2>
+<P>When you fail to bring up a tunnel, you'll need to find out:</P>
+<UL>
+<LI><A HREF="#state">what your connection state is,</A> and often</LI>
+<LI><A HREF="#find.pluto.error">an error message</A>.</LI>
+</UL>
+<P>before you can 
+<A HREF="#interpret.pluto.error">diagnose your problem</A>.</P>
+<H3><A NAME="state"></A>2.1 Determine Connection State</H3>
+<H4>Finding current state</H4>
+<P>You can see connection states (STATE_MAIN_I1 and so on) when you
+bring up a connection on the command line. If you have missed this,
+or brought up your connection automatically, use:
+</P>
+<PRE>ipsec auto --status</PRE>
+<P>The most relevant state is the last one reached.</P>
+<H4><VAR>What's this supposed to look like?</VAR></H4>
+<P>Negotiations should proceed though various states, in the processes of:</P>
+<OL>
+<LI>IKE negotiations (aka Phase 1, Main Mode, STATE_MAIN_*)</LI>
+<LI>IPSEC negotiations (aka Phase 2, Quick Mode, STATE_QUICK_*)</LI>
+</OL>
+<P>These are done and a connection is established when you see messages like:</P>
+<PRE>    000 #21: &quot;myconn&quot; STATE_MAIN_I4 (ISAKMP SA established)...
+    000 #2: &quot;myconn&quot; STATE_QUICK_I2 (sent QI2, IPsec SA established)...</PRE><P>
+Look for the key phrases are &quot;ISAKMP SA established&quot; and &quot;IPSec
+SA established&quot;, with the relevant connection name. Often, this happens 
+at STATE_MAIN_I4 and STATE_QUICK_I2, respectively.</P>
+<P><VAR>ipsec auto --status</VAR> will tell you what states <STRONG>have
+been achieved</STRONG>, rather than the current state. Since
+determining the current state is rather more difficult to do, current
+state information is not available from Linux FreeS/WAN. If you are
+actively bringing a connection up, the status report's last states
+for that connection likely reflect its current state. Beware, though,
+of the case where a connection was correctly brought up but is now
+downed: Linux FreeS/WAN will not notice this until it attempts to
+rekey. Meanwhile, the last known state indicates that the connection
+has been established.</P>
+<P>If your connection is stuck at STATE_MAIN_I1, skip straight to 
+<A HREF="#ikepath">here</A>.
+
+<H3><A NAME="find.pluto.error"></A>2.2 Finding error text</H3>
+<P>Solving most errors will require you to find verbose error text,
+either on the command line or in the logs.</P>
+<H4>Verbose start for more information</H4>
+<P>
+Note that you can get more detail from <VAR>ipsec auto</VAR> using
+the --verbose flag:</P>
+<PRE STYLE="margin-bottom: 0.2in">    ipsec auto --verbose --up west-east</PRE><P>
+More complete information can be gleaned from the <A HREF="#logusage">log
+files</A>.</P>
+
+<H4>Debug levels count</H4>
+<P>The amount of description you'll get here depends on ipsec.conf debug
+settings, <VAR>klipsdebug</VAR>= and <VAR>plutodebug</VAR>=. 
+When troubleshooting, set at least one of these to <VAR>all</VAR>, and 
+when done, reset it to <VAR>none</VAR> so your logs don't fill up.
+Note that you must have enabled the <VAR>klipsdebug</VAR> 
+<A HREF="install.html#allbut">compile-time option</A> for the 
+<VAR>klipsdebug</VAR> configuration switch to work.</P>
+<P>For negotiation problems <VAR>plutodebug</VAR> is most relevant.
+<VAR>klipsdebug</VAR> applies mainly to attempts to use an
+already-established connection. See also <A HREF="ipsec.html#parts">this</A>
+description of the division of duties within Linux FreeS/WAN.</P>
+<P>After raising your debug levels, restart Linux FreeS/WAN to ensure
+that ipsec.conf is reread, then recreate the error to generate
+verbose logs. 
+</P>
+<H4><VAR>ipsec barf</VAR> for lots of debugging information</H4>
+<P>
+<A HREF="manpage.d/ipsec_barf.8.html"><VAR>ipsec barf (8)</VAR></A>
+collects a bunch of useful debugging information, including these logs
+Use the command</P>
+<PRE>
+    ipsec barf &gt; barf.west
+</PRE>
+<P>to generate one.</P>
+<H4>Find the error</H4>
+<P>Search out the failure point in your logs.
+ Are there a handful of lines which succinctly describe how
+things are going wrong or contrary to your expectation? Sometimes the
+failure point is not immediately obvious: Linux FreeS/WAN's errors
+are usually not marked &quot;Error&quot;. Have a look in the 
+<A HREF="faq.html">FAQ</A>
+for what some common failures look like.</P>
+<P>Tip: problems snowball.
+Focus your efforts on the first problem, which is likely to be the
+cause of later errors.</P>
+<H4>Play both sides</H4>
+<P>Also find error text on the peer IPSec box.
+This gives you two perspectives on the same failure.</P>
+<P>At times you will require information which only one side has.
+The peer can merely indicate the presence of an error, and its 
+approximate point in the negotiations. If one side keeps retrying, 
+it may be because there is a show stopper on the other side. 
+Have a look at the other side and figure out what it doesn't like.</P>
+<P>If the other end is not Linux FreeS/WAN, the principle is the
+same: replicate the error with its most verbose logging on, and
+capture the output to a file.</P>
+<H3><A NAME="interpret.pluto.error"></A>2.3 Interpreting a Negotiation Error</H3>
+<H4><A NAME="ikepath"></A>Connection stuck at STATE_MAIN_I1</H4>
+<P>This error commonly happens because IKE (port 500) packets, needed 
+to negotiate an IPSec connection, cannot travel freely between your IPSec 
+gateways. See <A HREF="firewall.html#packets">our firewall document</A> 
+for details.</P>
+<H4>Other errors</H4>
+<P>Other errors require a bit more digging. Use the following resources:</P>
+<UL>
+	<LI><A HREF="faq.html">the FAQ</A> . Since this document is
+	constantly updated, the snapshot's FAQ may have a new entry relevant
+	to your problem.</LI>
+	<LI>our <A HREF="background.html">background document</A> .
+	Special considerations which, while not central to Linux FreeS/WAN,
+	are often tripped over. Includes problems with 
+      <a href="background.html#MTU.trouble">packet fragmentation</a>,
+      and considerations for
+	testing opportunism.</LI>
+	<LI>the <A HREF="mail.html#lists">list archives</A>. Each of the
+	searchable archives works differently, so it's worth checking each.
+	Use a search term which is generic, but identifies your error, for
+	example &quot;No connection is known for&quot;.
+	<BR>
+        Often, you will find that your question has been answered in the
+	past. Finding an archived answer is quicker than asking the list.
+	You may, however, find similar questions without answers. If you do,
+	send their URLs to the list with your trouble report. The additional
+	examples may help the list tech support person find your answer.</LI>
+	<LI>Look into the code where the error is being generated. The
+	pluto code is nicely documented with comments and meaningful
+	variable names.</LI>
+</UL>
+<P>If you have failed to solve your problem with the help of these
+resources, send a detailed problem report to the users list,
+following these <A HREF="#prob.report">guidelines</A>.</P>
+<H2><A NAME="use"></A>3. Using a Connection</H2>
+<H3>3.1 Orienting yourself</H3>
+<H4><VAR>How do I know if it works?</VAR></H4>
+<P>Test your connection by sending packets through it. The simplest way
+to do this is with ping, but the ping needs to <STRONG>test the correct 
+tunnel.</STRONG> See <A HREF="#testgates">this example scenario</A> if
+you don't understand this.<P>
+<P>If your ping returns, test any other connections you've brought
+u all check out, great. You may wish to <A HREF="#bigpacket">test
+with large packets</A> for MTU problems.</P>
+<H4><VAR>ipsec barf</VAR> is useful again</H4>
+<P>If your ping fails to return, generate an ipsec barf debugging
+report on each IPSec gateway. On a non-Linux FreeS/WAN
+implementation, gather equivalent information. Use this, and the tips
+in the next sections, to troubleshoot. Are you sure that both
+endpoints are capable of hearing and responding to ping?</P>
+<H3>3.2 Those pesky configuration errors</H3>
+<P>IPSec may be dropping your ping packets since they do not belong in the
+tunnels you have constructed:</P>
+<UL>
+<LI>Your ping may not test the tunnel you intend to test. For details, see our  
+<A HREF="faq.html#cantping">&quot;I can't ping&quot;</A> FAQ.
+</LI>
+<LI>
+Alternately, you may have a configuration error.
+For example, you may have configured one of the four possible tunnels between 
+two gateways, but not the one required to secure the important
+traffic you're now testing. In this case, add and start the tunnel,
+and try again.
+</LI>
+</UL>
+<P>In either case, you will often see a message like:</P>
+<PRE>klipsdebug... no eroute</PRE>
+<P>which we discuss in <A HREF="faq.html#no_eroute">this
+FAQ</A>.</P>
+<P>Note:</P>
+<UL>
+<LI><A HREF="glossary.html#NAT.gloss">Network Address Translation (NAT)</A> 
+and <A HREF="glossary.html#masq">IP masquerade</A> may have an effect on 
+which tunnels you need to configure.</LI>
+<LI>When testing a tunnel that protects a multi-node subnet, try several 
+subnet nodes as ping targets, in case one node is routing incorrectly.</LI>
+</UL>
+<H3><A NAME="route.firewall"></A>3.3 Check Routing and Firewalling</H3>
+<P>If you've confirmed your configuration assumptions, the problem is
+almost certainly with routing or firewalling. Isolate the problem
+using interface statistics, firewall statistics, or a packet sniffer.</P>
+<H4>Background:</H4>
+<UL>
+	<LI>Linux FreeS/WAN supplies all the special routing it needs;
+	you need only route packets out through your IPSec gateway. Verify
+	that on the <VAR>subnetted</VAR> machines you are using for your 
+        ping-test, your routing is as expected. I have seen a tunnel 
+        &quot;fail&quot; because the subnet machine sending packets 
+        out an alternate gateway (not our IPSec gateway) on their return path.
+	<LI>Linux FreeS/WAN requires particular <A HREF="firewall.html"> 
+        firewalling considerations</A>.
+	Check the firewall rules on your IPSec gateways and ensure that they
+	allow IPSec traffic through. Be sure that no other machine - for
+	example a router between the gateways - is blocking your IPSec
+	packets.
+</UL>
+<H4><A NAME="ifconfig"></A>View Interface and Firewall
+Statistics</H4>
+<P>Interface reports and firewall statistics can help you track down
+lost packets at a glance. Check any firewall statistics you may be keeping 
+on your IPSec gateways, for dropped packets.</P>
+
+<P><STRONG>Tip</STRONG>: You can take a snapshot of the packets processed 
+by your firewall with:</P>
+
+<PRE>    iptables -L -n -v</PRE>
+
+<P>You can get creative with "diff" to find out what happens to a
+particular packet during transmission.</P>
+
+<P>Both <VAR>cat /proc/net/dev</VAR> and <VAR>ifconfig</VAR> display
+interface statistics, and both are included in <VAR>ipsec barf</VAR>. Use
+either to check if any interface has dropped packets. If you find
+that one has, test whether this is related to your ping. While you
+ping continuously, print that interface's statistics several times.
+Does its drop count increase in proportion to the ping? If so, check
+why the packets are dropped there.</P>
+
+<P>To do this, look at the firewall rules that apply to that interface. If the
+interface is an IPSec interface, more information may be available in
+the log. Grep for the word &quot;drop&quot; in a log which was
+created with <VAR>klipsdebug=all</VAR> as the error happened.</P>
+<P>See also this <A HREF="#ifconfig1">discussion</A> on interpreting 
+<VAR>ifconfig</VAR> statistics.</P>
+<H3><A NAME="sniff"></A>3.4 When in doubt, sniff it out</H3>
+<P>If you have checked configuration assumptions, routing, and
+firewall rules, and your interface statistics yield no clue, it
+remains for you to investigate the mystery of the lost packet by the
+most thorough method: with a packet sniffer (providing, of course, 
+that this is legal where you are working).
+<P>In order to detect packets on the ipsec virtual interfaces,
+you will need an up-to-date sniffer (tcpdump, ethereal, ksnuffle) on
+your IPSec gateway machines. You may also find it useful to sniff the ping
+endpoints.</P>
+<H4>Anticipate your packets' path</H4>
+<P>Ping, and examine each interface along the projected path, checking for your 
+ping's arrival. If it doesn't get to the the next stop, you have narrowed 
+down where to look for it. In this way, you can isolate a problem area, 
+and narrow your troubleshooting focus.</P>
+<P>Within a machine running Linux FreeS/WAN, this 
+<A HREF="firewall.html#packets">packet flow diagram</A> will help you 
+anticipate a packet's path.
+<P>Note that:</P>
+<UL>
+<LI>
+from the perspective of the tunneled packet, the entire tunnel is one hop. 
+That's explained in <A HREF="faq.html#no_trace">this</A> FAQ.
+</LI>
+<LI>
+ an encapsulated IPSec packet will look different, when
+sniffed, from the plaintext packet which generated it. You
+can see plaintext packets entering an IPSec interface and the
+resulting cyphertext packets as they emerge from the corresponding
+physical interface. 
+</LI>
+</UL>
+<P>Once you isolate where the packet is lost, take a closer look at
+firewall rules, routing and configuration assumptions as they affect
+that specific area. If the packet is lost on an IPSec gateway, comb
+through <VAR>klipsdebug</VAR> output for anomalies. 
+</P>
+<P>If the packet goes through both gateways successfully and reaches
+the ping target, but does not return, suspect routing. Check that the
+ping target routes packets back to the IPSec gateway.</P>
+<H3><A NAME="find.use.error"></A>3.5 Check your logs</H3>
+<P>Here, too, log information can be useful. Start with the 
+<A HREF="#find.pluto.error">guidelines above</A>.</P>
+<P>For connection use problems, set <VAR>klipsdebug=all</VAR>. Note
+that you must have enabled the <VAR>klipsdebug</VAR> 
+<A HREF="install.html#allbut">compile-time option</A> to do this. 
+Restart Linux FreeS/WAN so that it rereads <VAR>ipsec.conf</VAR>, 
+then recreate the error condition. When searching through 
+<VAR>klipsdebug</VAR> data, look especially for the keywords
+&quot;drop&quot; (as in dropped packets) and &quot;error&quot;.</P>
+<P>Often the problem with connection use is not software error, but
+rather that the software is behaving contrary to expectation. 
+</P>
+<H4><A NAME="interpret.use.error"></A>Interpreting log text</H4>
+<P>To interpret the Linux FreeS/WAN log text you've found, use the
+same resources as indicated for troubleshooting 
+connection negotiation: 
+<A HREF="faq.html">the FAQ</A> , our
+<A HREF="background.html">background document</A>, and the 
+<A HREF="mail.html#lists">list archives</A>.
+Looking in the KLIPS code is only for the very brave.</P>
+<P>If you are still stuck, send a <A HREF="#prob.report">detailed
+problem report</A> to the users' list.</P>
+<H3><A NAME="bigpacket"></A>3.6 More testing for the truly thorough</H3>
+<H4>Large Packets</H4>
+<P>If each of your connections passed the ping test, you may wish to
+test by pinging with large packets (2000 bytes or larger). If it does
+not return, suspect MTU issues, and see this <A HREF="background.html#MTU.trouble">discussion</A>.</P>
+<H4>Stress Tests</H4>
+<P>In most users' view, a simple ping test, and perhaps a
+large-packet ping test suffice to indicate a working IPSec
+connection.</P>
+<P>Some people might like to do additional stress tests prior to
+production use. They may be interested in this <A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/12/msg00224.html">testing
+protocol</A> we use at interoperation conferences, aka &quot;bakeoffs&quot;.
+We also have a <VAR>testing</VAR> directory that ships with the
+release.</P>
+<H2><A NAME="prob.report"></A>4. Problem Reporting</H2>
+<H3>4.1 How to ask for help</H3>
+<P>Ask for troubleshooting help on the users' mailing list,
+<A HREF="mailto:users@lists.freeswan.org">users@lists.freeswan.org</A>.
+While sometimes an initial query with a quick description of your
+intent and error will twig someone's memory of a similar problem,
+it's often necessary to send a second mail with a complete problem
+report. 
+</P>
+
+
+<P>When reporting problems to the mailing list(s), please include: 
+</P>
+<UL>
+	<LI>a brief description of the problem</LI>
+	<LI>if it's a compile problem, the actual output from make,
+	showing the problem. Try to edit it down to only the relevant part,
+	but when in doubt, be as complete as you can. If it's a kernel
+	compile problem, any relevant out.* files</LI>
+	<LI>if it's a run-time problem, pointers to where we can find the
+	complete output from &quot;ipsec barf&quot; from BOTH ENDS (not just
+	one of them). Remember that it's common outside the US and Canada to
+	pay for download volume, so if you can't post barfs on the web and
+	send the URL to the mailing list, at least compress them with tar or
+	gzip.<BR>
+	If you can, try to simplify the case that is causing the problem.
+	In particular, if you clear your logs, start FreeS/WAN with no other
+	connections running, cause the problem to happen, and then do <VAR>ipsec
+	barf</VAR> on both ends immediately, that gives the smallest and
+	least cluttered output.</LI>
+	<LI>any other error messages, complaints, etc. that you saw.
+	Please send the complete text of the messages, not just a summary.</LI>
+	<LI>what your network setup is. Include subnets, gateway
+	addresses, etc. A schematic diagram is a
+	good format for this information.</LI>
+	<LI>exactly what you were trying to do with Linux FreeS/WAN, and
+	exactly what went wrong</LI>
+	<LI>a fix, if you have one. But remember, you are sending mail to
+	people all over the world; US residents and US citizens in
+	particular, please read doc/exportlaws.html before sending code --
+	even small bug fixes -- to the list or to us.</LI>
+	<LI>When in doubt about whether to include some seemingly-trivial
+	item of information, include it. It is rare for problem reports to
+	have too much information, and common for them to have too little.</LI>
+</UL>
+
+<P>Here are some good general guidelines on bug reporting:
+<a href="http://tuxedo.org/~esr/faqs/smart-questions.html">How To Ask Questions
+The Smart Way</a> and <a
+href="http://www.chiark.greenend.org.uk/~sgtatham/bugs.html">How to Report
+Bugs Effectively</a>.</p>
+
+
+<H3>4.2 Where to ask</H3>
+<P>To report a problem, send mail about it to the users' list. If you
+are certain that you have found a bug, report it to the bugs list. If
+you encounter a problem while doing your own coding on the Linux
+FreeS/WAN codebase and think it is of interest to the design team,
+notify the design list. When in doubt, default to the users' list.
+More information about the mailing lists is found <A HREF="mail.html#lists">here</A>.</P>
+<P>For a number of reasons -- including export-control regulations
+affecting almost any <STRONG>private</STRONG> discussion of
+encryption software -- we prefer that problem reports and discussions
+go to the lists, not directly to the team. Beware that the list goes
+worldwide; US citizens, read this important information about your
+<A HREF="politics.html#exlaw">export laws</A>. If you're using this
+software, you really should be on the lists. To get onto them, visit
+<A HREF="http://lists.freeswan.org/">lists.freeswan.org</A>.</P>
+<P>If you do send private mail to our coders or want a private reply
+from them, please make sure that the return address on your mail
+(From or Reply-To header) is a valid one. They have more important
+things to do than to unravel addresses that have been mangled in an
+attempt to confuse spammers. 
+</P>
+<H2><A NAME="notes"></A>5. Additional Notes on Troubleshooting</H2>
+<P>The following sections supplement the Guide: <A HREF="#system.info">information
+available on your system</A>; <A HREF="#testgates">testing between
+security gateways</A>; <A HREF="#ifconfig1">ifconfig reports for
+KLIPS debugging</A>; <A HREF="#gdb">using GDB on Pluto</A>.</P>
+<H3><A NAME="system.info"></A>5.1 Information available on your
+system</H3>
+<H4><A NAME="logusage"></A>Logs used</H4>
+<P>Linux FreeS/WAN logs to:</P>
+<UL>
+	<LI>/var/log/secure (or, on Debian, /var/log/auth.log)</LI>
+	<LI>/var/log/messages</LI>
+</UL>
+<P>Check both places to get full information. If you find nothing,
+check your <VAR>syslogd.conf(5)</VAR> to see where your
+/etc/syslog.conf or equivalent is directing <VAR>authpriv</VAR>
+messages.</P>
+<H4><A NAME="pages"></A>man pages provided</H4>
+<DL>
+	<DT><A HREF="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</A> 
+	</DT><DD>
+	Manual page for IPSEC configuration file. 
+	</DD><DT>
+	<A HREF="manpage.d/ipsec.8.html">ipsec(8)</A> 
+	</DT><DD STYLE="margin-bottom: 0.2in">
+	Primary man page for ipsec utilities. 
+	</DD></DL>
+<P>
+Other man pages are on <A HREF="manpages.html">this list</A> and in</P>
+<UL>
+	<LI>/usr/local/man/man3</LI>
+	<LI>/usr/local/man/man5</LI>
+	<LI>/usr/local/man/man8/ipsec_*</LI>
+</UL>
+<H4><A NAME="statusinfo"></A>Status information</H4>
+<DL>
+	<DT>ipsec auto --status 
+	</DT><DD>
+	Command to get status report from running system. Displays Pluto's
+	state. Includes the list of connections which are currently &quot;added&quot;
+	to Pluto's internal database; lists state objects reflecting ISAKMP
+	and IPsec SAs being negotiated or installed. 
+	</DD><DT>
+	ipsec look 
+	</DT><DD>
+	Brief status info. 
+	</DD><DT>
+	ipsec barf 
+	</DT><DD STYLE="margin-bottom: 0.2in">
+	Copious debugging info. 
+	</DD></DL>
+<H3>
+<A NAME="testgates"></A>5.2 Testing between security gateways</H3>
+<P>Sometimes you need to test a subnet-subnet tunnel. This is a
+tunnel between two security gateways, which protects traffic on
+behalf of the subnets behind these gateways. On this network:</P>
+<PRE>     Sunset==========West------------------East=========Sunrise
+                     IPSec gateway         IPSec gateway
+           local net       untrusted net       local net</PRE><P>
+you might name this tunnel sunset-sunrise. You can test this tunnel
+by having a machine behind one gateway ping a machine behind the
+other gateway, but this is not always convenient or even possible.</P>
+<P>Simply pinging one gateway from the other is not useful. Such a
+ping does not normally go through the tunnel. <STRONG>The tunnel
+handles traffic between the two protected subnets, not between the
+gateways</STRONG> . Depending on the routing in place, a ping might</P>
+<UL>
+	<LI>either succeed by finding an
+	unencrypted route</LI>
+	<LI>or fail by finding no route. Packets without an IPSEC eroute
+	are discarded.</LI>
+</UL>
+<P><STRONG>Neither event tells you anything about the tunnel</STRONG>.
+You can explicitly create an eroute to force such packets through the
+tunnel, or you can create additional tunnels as described in our
+<A HREF="config.html#multitunnel">configuration document</A>, but
+those may be unnecessary complications in your situation.</P>
+<P>The trick is to explicitly test between <STRONG>both gateways'
+private-side IP addresses</STRONG>. Since the private-side interfaces
+are on the protected subnets, the resulting packets do go via the
+tunnel. Use either ping -I or traceroute -i, both of which allow you
+to specify a source interface. (Note: unsupported on older Linuxes).
+The same principles apply for a road warrior (or other) case where
+only one end of your tunnel is a subnet.</P>
+<H3><A NAME="ifconfig1"></A>5.3 ifconfig reports for KLIPS debugging</H3>
+<P>When diagnosing problems using ifconfig statistics, you may wonder
+what type of activity increments a particular counter for an ipsecN
+device. Here's an index, posted by KLIPS developer Richard Guy
+Briggs:</P>
+<PRE>Here is a catalogue of the types of errors that can occur for which
+statistics are kept when transmitting and receiving packets via klips.
+I notice that they are not necessarily logged in the right counter.
+. . .
+
+Sources of ifconfig statistics for ipsec devices
+
+rx-errors:
+- packet handed to ipsec_rcv that is not an ipsec packet.
+- ipsec packet with payload length not modulo 4.
+- ipsec packet with bad authenticator length.
+- incoming packet with no SA.
+- replayed packet.
+- incoming authentication failed.
+- got esp packet with length not modulo 8.
+
+tx_dropped:
+- cannot process ip_options.
+- packet ttl expired.
+- packet with no eroute.
+- eroute with no SA.
+- cannot allocate sk_buff.
+- cannot allocate kernel memory.
+- sk_buff internal error.
+
+
+The standard counters are:
+
+struct enet_statistics
+{
+        int        rx_packets;                /* total packets received */
+        int        tx_packets;                /* total packets transmitted */
+        int        rx_errors;                /* bad packets received */
+        int        tx_errors;                /* packet transmit problems */
+        int        rx_dropped;                /* no space in linux buffers */
+        int        tx_dropped;                /* no space available in linux */
+        int        multicast;                /* multicast packets received */
+        int        collisions;
+
+        /* detailed rx_errors: */
+        int        rx_length_errors;
+        int        rx_over_errors;                /* receiver ring buff overflow */
+        int        rx_crc_errors;                /* recved pkt with crc error */
+        int        rx_frame_errors;        /* recv'd frame alignment error */
+        int        rx_fifo_errors;                /* recv'r fifo overrun */
+        int        rx_missed_errors;        /* receiver missed packet */
+
+        /* detailed tx_errors */
+        int        tx_aborted_errors;
+        int        tx_carrier_errors;
+        int        tx_fifo_errors;
+        int        tx_heartbeat_errors;
+        int        tx_window_errors;
+};
+
+of which I think only the first 6 are useful.</PRE><H3>
+<A NAME="gdb"></A>5.4 Using GDB on Pluto</H3>
+<P>You may need to use the GNU debugger, gdb(1), on Pluto. This
+should be necessary only in unusual cases, for example if you
+encounter a problem which the Pluto developer cannot readily
+reproduce or if you are modifying Pluto. 
+</P>
+<P>Here are the Pluto developer's suggestions for doing this: 
+</P>
+<PRE>Can you get a core dump and use gdb to find out what Pluto was doing
+when it died?
+
+To get a core dump, you will have to set dumpdir to point to a
+suitable directory (see <A HREF="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</A>).
+
+To get gdb to tell you interesting stuff:
+        $ script
+        $ cd dump-directory-you-chose
+        $ gdb /usr/local/lib/ipsec/pluto core
+        (gdb) where
+        (gdb) quit
+        $ exit
+
+The resulting output will have been captured by the script command in
+a file called &quot;typescript&quot;.  Send it to the list.
+
+Do not delete the core file.  I may need to ask you to print out some
+more relevant stuff.</PRE><P>
+Note that the <VAR>dumpdir</VAR> parameter takes effect only when the
+IPsec subsystem is restarted -- reboot or ipsec setup restart.</P>
+<P><BR><BR>
+</P>
+</BODY>
+</HTML>
diff --git a/doc/src/uml-rhroot-list.txt b/doc/src/uml-rhroot-list.txt
new file mode 100644
index 000000000..198997032
--- /dev/null
+++ b/doc/src/uml-rhroot-list.txt
@@ -0,0 +1,91 @@
+filesystem-2.1.6-2
+glibc-common-2.2.4-13
+slang-1.4.4-4
+newt-0.50.33-1
+mktemp-1.5-11
+syslinux-1.52-2
+which-2.12-3
+zlib-devel-1.1.3-24
+ntsysv-1.2.24-1
+db1-devel-1.85-7
+e2fsprogs-1.23-2
+iputils-20001110-6
+mingetty-0.9.4-18
+pwdb-0.61.1-3
+bash-2.05-8
+bzip2-1.0.1-4
+libstdc++-2.96-98
+logrotate-3.5.9-1
+rootfiles-7.2-1
+bash-doc-2.05-8
+iproute-2.2.4-14
+ncurses-5.2-12
+diffutils-2.7.2-2
+findutils-4.1.7-1
+gzip-1.3-15
+readline-4.2-2
+tmpwatch-2.8-2
+cpio-2.4.2-23
+gawk-3.1.0-3
+less-358-21
+procps-X11-2.0.7-11
+sed-3.02-10
+vim-minimal-5.8-7
+fileutils-4.1-4
+sysklogd-1.4.1-4
+mount-2.11g-5
+rpm-4.0.3-1.03
+glib-devel-1.2.10-5
+bzip2-libs-1.0.1-4
+tar-1.13.19-6
+cracklib-dicts-2.7-12
+passwd-0.64.1-7
+pam-devel-0.75-14
+SysVinit-2.78-19
+krb5-libs-1.2.2-13
+pam_krb5-1.46-1
+krbafs-utils-1.0.9-2
+setup-2.5.7-1
+basesystem-7.0-2
+glibc-2.2.4-13
+popt-1.6.3-1.03
+setuptool-1.8-2
+shadow-utils-20000902-4
+zlib-1.1.3-24
+chkconfig-1.2.24-1
+db1-1.85-7
+db3-3.2.9-4
+file-3.35-2
+losetup-2.11g-5
+net-tools-1.60-3
+netconfig-0.8.11-7
+libtermcap-2.0.8-28
+libtermcap-devel-2.0.8-28
+bzip2-devel-1.0.1-4
+libstdc++-devel-2.96-98
+modutils-2.4.6-4
+crontabs-1.10-1
+MAKEDEV-3.2-5
+grep-2.4.2-7
+psmisc-20.1-2
+readline-devel-4.2-2
+e2fsprogs-devel-1.23-2
+ed-0.2-21
+vim-common-5.8-7
+procps-2.0.7-11
+redhat-release-7.2-1
+time-1.7-14
+cracklib-2.7-12
+console-tools-19990829-36
+textutils-2.0.14-2
+dev-3.2-5
+glib-1.2.10-5
+termcap-11.0.1-10
+info-4.0b-3
+words-2-17
+pam-0.75-14
+util-linux-2.11f-9
+sh-utils-2.0.11-5
+initscripts-6.40-1
+krbafs-1.0.9-2
+krbafs-devel-1.0.9-2
diff --git a/doc/src/uml-rhroot.html b/doc/src/uml-rhroot.html
new file mode 100644
index 000000000..ca05a2073
--- /dev/null
+++ b/doc/src/uml-rhroot.html
@@ -0,0 +1,116 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
+<HTML>
+  <HEAD>
+    <TITLE>Building a RedHat root image</TITLE>
+    <!-- Created by: Michael Richardson, 22-Nov-2001 -->
+    <!-- Changed by: Michael Richardson, 22-Nov-2001 -->
+
+
+  </HEAD>
+  <BODY>
+    <H1>Building a RedHat root image</H1>
+
+<P>
+The image required to use User-Mode-Linux is just a normal set of executables.
+These can be extracted from a RedHat distribution using the following proceedure.
+</P>
+
+<P>
+There is a script in testing/utils called <CODE>uml-rhroot.sh</CODE>. It takes
+two arguments:
+<UL>
+<LI> a directory in which to put resulting directory tree. 
+<LI> a directory tree containing the RedHat distribution RPMs. This may be
+  in one of three forms:
+<UL>
+<LI> a directory containing the directories "disc1" and "disc2". These 
+  could be ISO images that are mounted loopback via, for instance:
+<PRE>
+<CODE>
+mkdir -p /distros/redhat/7.2/disc1 /distros/redhat/7.2/disc1
+mount -t iso9660 -o loop,ro /distros/redhat/7.2/enigma-i386-disc1.iso /distros/redhat/7.2/disc1
+mount -t iso9660 -o loop,ro /distros/redhat/7.2/enigma-i386-disc2.iso /distros/redhat/7.2/disc2 
+</CODE>
+</PRE>
+or even two real CDroms mounted somewhere. In the example above, use "/distros/redhat/7.2" as the distribution directory.
+</LI>
+<LI> a directory containing a "merged" disc1 and disc2 as suggested by RedHat in <A HREF="http://www.redhat.com/docs/manuals/linux/RHL-7.2-Manual/install-guide/s1-install-network.html#S2-INSTALL-SETUPSERVER">http://www.redhat.com/docs/manuals/linux/RHL-7.2-Manual/install-guide/s1-install-network.html under "Setting up the Server"</A>.
+<LI> a directory containing all the required RPMs. (See <A HREF="uml-rhroot-list7.2.txt">list of RPMs</A>)</LI>
+</UL>
+</UL>
+</P>
+
+<P>The unpacked distribution will take approximately 133Mb. You will
+  want to locate this on the same partition as your intended root
+  trees for your User-Mode-Linux's as this will permit hard links to
+  be used, saving disk space.  
+</P>
+
+<P>
+  Because the RPM command used uses the chroot(2) system call and
+  needs to change ownership of the files that it creates, it must be
+  run as root. Afterward, you should chown the entire directory to the
+  userid that you will be using for testing (i.e. probably
+  yours). It should eventually suffices to make sure that you can read
+  every file.
+</P>
+
+<P>
+You should be able to chroot to this directory and run programs. If
+you can not at least run ls, then there is a problem.
+</P>
+<P>
+Expect a couple of errors about install-info.
+</P>
+
+<P>
+An example:
+<PRE>
+<CODE>
+Script started on Thu Nov 22 15:51:15 2001
+cassidy:/c2/user-mode-linux# df
+Filesystem           1k-blocks      Used Available Use% Mounted on
+/dev/hda1              3844408   1673528   1975584  46% /
+/dev/hda3             12495048   1823404  10036884  16% /home
+/dev/hdc1             10325748    805056   8996172   9% /c1
+/dev/hdc2             10325780   4815160   4986100  50% /c2
+/dev/hdc3             10325780   2972480   6828780  31% /c3
+/dev/hdc4              7495084   3059640   4054704  44% /c4
+/distros/redhat/7.2/enigma-i386-disc1.iso
+                        662072    662072         0 100% /distros/redhat/7.2/disc1
+/distros/redhat/7.2/enigma-i386-disc2.iso
+                        653740    653740         0 100% /distros/redhat/7.2/disc2
+cassidy:/c2/user-mode-linux# /c2/freeswan/sandbox-main/testing/utils/uml-rhroot.sh 
+Usage: /c2/freeswan/sandbox-main/testing/utils/uml-rhroot.sh rootdir cdimagedir
+cassidy:/c2/user-mode-linux# /c2/freeswan/sandbox-main/testing/utils/uml-rhroot.sh /c2/user-mode-linux/rpm-root/root /distros/redhat/7.2
+Assuming RH disc1 at /distros/redhat/7.2/disc1/RedHat/RPMS
+        and disc2 at /distros/redhat/7.2/disc2/RedHat/RPMS
+/var/tmp/rpm-tmp.99149: /sbin/install-info: No such file or directory
+error: execution of %post scriptlet from textutils-2.0.14-2 failed, exit status 127
+cat: /proc/mounts: No such file or directory
+warning: /var/lib/rpm/Basenames created as /var/lib/rpm/Basenames.rpmnew
+warning: /var/lib/rpm/Conflictname created as /var/lib/rpm/Conflictname.rpmnew
+warning: /var/lib/rpm/Group created as /var/lib/rpm/Group.rpmnew
+warning: /var/lib/rpm/Name created as /var/lib/rpm/Name.rpmnew
+warning: /var/lib/rpm/Packages created as /var/lib/rpm/Packages.rpmnew
+warning: /var/lib/rpm/Providename created as /var/lib/rpm/Providename.rpmnew
+warning: /var/lib/rpm/Requirename created as /var/lib/rpm/Requirename.rpmnew
+warning: /var/lib/rpm/Triggername created as /var/lib/rpm/Triggername.rpmnew
+You should now chown it to yourself.
+cassidy:/c2/user-mode-linux# chown -R mcr rpm-root/root
+cassidy:/c2/user-mode-linux# ls rpm-root/root
+bin   dev  home    lib	opt   root  tmp  var
+boot  etc  initrd  mnt	proc  sbin  usr
+cassidy:/c2/user-mode-linux# chroot rpm-root/root
+cassidy:/# ls
+bin   dev  home    lib  opt   root  tmp  var
+boot  etc  initrd  mnt  proc  sbin  usr
+cassidy:/# exit
+cassidy:/c2/user-mode-linux# exit
+Script done on Thu Nov 22 15:54:33 2001
+</CODE>
+</PRE>
+
+
+  </BODY>
+</HTML>
\ No newline at end of file
diff --git a/doc/src/uml-stack-trace.html b/doc/src/uml-stack-trace.html
new file mode 100644
index 000000000..1b08ed7d1
--- /dev/null
+++ b/doc/src/uml-stack-trace.html
@@ -0,0 +1,129 @@
+<PRE>
+To: Michael Richardson <mcr@sandelman.ottawa.on.ca>
+Cc: user-mode-linux-devel@lists.sourceforge.net
+From: Jeff Dike <jdike@karaya.com>
+Subject: [uml-devel] Re: stack trace
+Date: Mon, 16 Sep 2002 22:36:06 -0500
+
+mcr@sandelman.ottawa.on.ca said:
+> Can you post (on list or web site) a "script" output of you trying to
+> get the right stack out of a stuck uml (tracing myself)...? 
+
+Yup.  Here we go...
+
+Here, I attach to the tracing thread and get the stack of the current thread,
+which happens to be the idle thread.
+
+um 1013: gdb linux 14936
+GNU gdb 5.0rh-5 Red Hat Linux 7.1
+Copyright 2001 Free Software Foundation, Inc.
+GDB is free software, covered by the GNU General Public License, and you are
+welcome to change it and/or distribute copies of it under certain conditions.
+Type "show copying" to see the conditions.
+There is absolutely no warranty for GDB.  Type "show warranty" for details.
+This GDB was configured as "i386-redhat-linux"...
+/home/jdike/linux/2.4/um/14936: No such file or directory.
+Attaching to program: /home/jdike/linux/2.4/um/linux, process 14936
+0xa014efe9 in __wait4 ()
+
+# This is how you get the current task in the tracing thread - get_current()
+# only works in a kernel thread.
+(gdb) p (struct task_struct *)cpu_tasks[0].task
+$2 = (struct task_struct *) 0xa01c0000
+
+# Get the host pid of that task.
+(gdb) p $2.thread.extern_pid
+$3 = 14939
+
+# Get the current ip and sp.
+(gdb) shell cat /proc/14939/stat
+14939 (linux) T 14936 14936 883 34816 14936 64 5 3 806 7 62 12 0 0 9 0 0 2 
+588043 142770176 5008 4294967295 2684358656 2686348640 3221223520 2686205764
+                                                               sp ^^^^^^^^^^ 
+   2685727185 73728 201392128 167776768 268444672 3222308129 0 0 17 0
+ip ^^^^^^^^^^
+
+# the sp and ip are items 4 and 5 after the 4294967295 (on 2.2 hosts, that's
+2^31 - 1 rather than 2^32 - 1).
+
+(gdb) p/x 2686205764
+$4 = 0xa01c3f44
+(gdb) p/x 2685727185
+$5 = 0xa014f1d1
+
+# Where's the ip?
+(gdb) i sym 0xa014f1d1
+nanosleep + 17 in section .text
+
+# look at the stack around the sp
+(gdb) x/32x 0xa01c3f30
+0xa01c3f30 :     0x00000000      0x00000000      0xa01c3f60      0xa00020a8
+0xa01c3f40 :     0x00000004      0xa012e891      0xa01c3f58      0xa01c3f58
+0xa01c3f50 :     0xa01c3f70      0xa0023667      0x00000009      0x3b023380
+0xa01c3f60 :     0xa01c3fa0      0xa012a21d      0x0000000a      0xa01c0000
+0xa01c3f70 :     0xa01c3fa0      0xa012a213      0x00000003      0x00000024
+0xa01c3f80 :     0xa01c3fa0      0xa0011bc4      0xa012b25c      0x00000000
+0xa01c3f90 :     0xa01c3fb0      0x00000000      0xa01c3ffc      0x0000000d
+0xa01c3fa0 :     0xa01c3fb0      0xa000c50e      0xa01812e0      0xa01c3ffc
+
+# The trick here is to locate a frame near the current sp.  You're looking
+# for a consecutive pair of longwords (fp, ip) having the properties that:
+#	fp is on the current kernel stack and points further up it
+#	ip is a text address (if you can't recognize a UML text address by
+# sight, print out &_stext and &_etext)
+#
+# Starting at 0xa01c3f44, the first pair of works satisfying these requirements
+# is at 0xa01c3f50.
+# So, print that pair out as hex.
+(gdb) p/x *((int (*)[2])0xa01c3f50)
+$9 = {0xa01c3f70, 0xa0023667}
+
+# Now, we start climbing the stack.
+(gdb) p/x *((int (*)[2])$[0])
+$10 = {0xa01c3fa0, 0xa012a213}
+(gdb) 
+$11 = {0xa01c3fb0, 0xa000c50e}
+(gdb) 
+$12 = {0xa01c3fc0, 0xa000356d}
+(gdb) 
+$13 = {0xa01c3fd0, 0xa013082f}
+(gdb) 
+$14 = {0xa01c3ff0, 0xa012fbdd}
+# Stop when you see a NULL frame pointer or gdb bitches at you.
+(gdb) 
+$15 = {0x0, 0xa01513aa}
+
+# Now we get the symbolic version of the stack with 'i sym' of the second item
+# in each pair. 
+(gdb) i sym 0xa0023667
+check_pgt_cache + 23 in section .text
+(gdb) i sym 0xa012a213
+cpu_idle + 123 in section .text
+(gdb) i sym 0xa000c50e
+rest_init + 46 in section .text
+(gdb) i sym 0xa000356d
+start_kernel + 361 in section .text.init
+(gdb) i sym 0xa013082f
+start_kernel_proc + 63 in section .text
+(gdb) i sym 0xa012fbdd
+signal_tramp + 209 in section .text
+(gdb) i sym 0xa01513aa
+thread_start + 4 in section .text
+
+# You can also get line number information with 'i line'.
+(gdb) i line *0xa012a213
+Line 488 of "process_kern.c" starts at address 0xa012a213 <cpu_idle+123>
+   and ends at 0xa012a21d <cpu_idle+133>.
+(gdb) 
+
+
+-------------------------------------------------------
+Sponsored by: AMD - Your access to the experts on Hammer Technology! 
+Open Source & Linux Developers, register now for the AMD Developer 
+Symposium. Code: EX8664 http://www.developwithamd.com/developerlab
+_______________________________________________
+User-mode-linux-devel mailing list
+User-mode-linux-devel@lists.sourceforge.net
+https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
+
+</PRE>
\ No newline at end of file
diff --git a/doc/src/umltesting.html b/doc/src/umltesting.html
new file mode 100644
index 000000000..df62a9ae2
--- /dev/null
+++ b/doc/src/umltesting.html
@@ -0,0 +1,478 @@
+<html>
+<head>
+<title>FreeS/WAN User-Mode-Linux testing guide</title>
+<!-- Changed by: Michael Richardson, 05-Mar-2003 -->
+<meta name="keywords" content="Linux, IPsec, VPN, security, FreeSWAN, testing, User-Mode-Linux, UML">
+
+<!--
+
+Written by Michael Richardson for the Linux FreeS/WAN project
+Freely distributable under the GNU General Public License
+
+More information at www.freeswan.org
+Feedback to users@lists.freeswan.org
+
+$Id: umltesting.html,v 1.1 2004/03/15 20:35:24 as Exp $
+
+$Log: umltesting.html,v $
+Revision 1.1  2004/03/15 20:35:24  as
+added files from freeswan-2.04-x509-1.5.3
+
+Revision 1.23  2003/09/18 15:12:11  dhr
+
+fix link to kernel.org mirrors page
+
+Revision 1.22  2003/03/07 03:49:25  dhr
+
+fix recommended version of uml-patch
+
+Revision 1.21  2003/03/06 08:37:03  dhr
+
+capture more of MCR's knowledge about BIND
+
+Revision 1.20  2003/03/06 02:15:44  mcr
+	added note about need for bind9.
+
+Revision 1.19  2003/03/05 23:20:39  mcr
+	updates from -47 to -53.
+
+Revision 1.18  2003/02/27 08:25:48  dhr
+
+update to reflect newer umlfreeroot
+
+Revision 1.17  2003/02/27 08:16:45  dhr
+
+make clear what is the latest version of the UML patch that we've used
+
+Revision 1.16  2003/02/21 01:35:31  mcr
+	updated latest umlfreeroot to 15.1.
+
+Revision 1.15  2003/01/21 03:26:34  mcr
+	updated documentation on UML state.
+
+Revision 1.14  2002/11/11 16:43:35  mcr
+	adjusted formatting of uml_netjig notes.
+
+Revision 1.13  2002/11/08 10:13:05  mcr
+	updated documentation for 2.4.19
+
+Revision 1.12  2002/11/03 23:44:23  mcr
+	fixed some formatting in umltesting.html
+	added some notes about NETJIGWAITUSER re: having tests
+	prompt before they exit. Helps with debugging.
+
+Revision 1.11  2002/10/31 19:01:31  mcr
+	documentation for RUN_*_SCRIPT.
+
+Revision 1.10  2002/09/15 23:57:59  dhr
+
+update suggested umlfreeroot
+
+Revision 1.9  2002/09/15 19:28:05  mcr
+	added some comments about problems with UMLs.
+
+Revision 1.8  2002/09/11 20:00:25  mcr
+	updated umlroot rev to 8.0.
+
+Revision 1.7  2002/09/09 21:37:43  mcr
+	updated document to reference currently working kernel+UML.
+
+Revision 1.6  2002/08/02 22:43:35  mcr
+	added section on debugging with UMLs.
+
+Revision 1.5  2002/05/30 18:47:57  dhr
+
+Update from experience:
+- fixed HTML bugs
+- restructure slightly
+- added another intro paragraph
+- mentioned lack of Super User requirements
+- added tcpdump build and install procedure
+- added uml utils build procedure
+- added invitation to try "make check"
+- fixed minor typos and mistakes
+
+Revision 1.4  2002/03/12 21:10:37  mcr
+	removed instruction on downloading umlminishare, as this is
+	now simply included in umlrootXXX. reformated some other text.
+
+Revision 1.3  2002/01/29 02:21:21  mcr
+	updated instructions for 2.4.17, and for newest UMLroot.
+
+Revision 1.2  2001/11/27 05:24:09  mcr
+	added reference to uml-rhroot, but commented out.
+	This proceedure is not yet ready for prime time.
+
+Revision 1.1  2001/11/05 04:35:57  mcr
+	adapted text from design list posting into HTML for Sandy.
+
+
+-->
+</head>
+
+<body>
+
+<h1><a name="umltesting">User-Mode-Linux Testing guide</a></h1>
+
+<p>
+User mode linux is a way to compile a linux kernel such that it can run as a
+process in another linux system (potentially as a *BSD or Windows process
+later). See <A HREF="http://user-mode-linux.sourceforge.net/">http://user-mode-linux.sourceforge.net/</A>
+</P>
+
+<p>
+UML is a good platform for testing and experimenting with FreeS/WAN.
+It allows several network nodes to be simulated on a single machine.
+Creating, configuring, installing, monitoring, and controling these
+nodes is generally easier and easier to script with UML than real
+hardware.
+</p>
+
+<p>
+You'll need about 500Mb of disk space for a full sunrise-east-west-sunset
+setup. You can possibly get this down by 130Mb if you remove the
+sunrise/sunset kernel build. If you just want to run, then you can even
+remove the east/west kernel build.
+</p>
+<p>
+Nothing need be done as super user.  In a couple of steps, we note
+where super user is required to install commands in system-wide
+directories, but ~/bin could be used instead.  UML seems to use a
+system-wide /tmp/uml directory so different users may interfere with
+one another. Later UMLs use ~/.uml instead, so multiple users running UML 
+tests should not be a problem, but note that a single user running
+the UML tests will only be able run one set. Further, UMLs sometimes
+get stuck and hang around. These "zombies" (most will actually be in
+the "T" state in the process table) will interfere with subsequent tests.
+</P>
+<H2>Preliminary Notes on BIND</H2>
+
+<P>
+As of 2003/3/1, the Light-Weight Resolver is used by pluto. This requires
+that BIND9 be running. It also requires that BIND9 development libraries
+be present in the build environment. The DNSSEC code is only truly functional
+in BIND9 snapshots. The library code could be 9.2.2, we believe. We are
+using BIND9 20021115 snapshot code from
+<A HREF="ftp://ftp.isc.org/isc/bind9/snapshots">ftp://ftp.isc.org/isc/bind9/snapshots</A>.
+</P>
+<P>
+FreeS/WAN may well require a newer BIND than is on your system.
+Many distributions have moved to BIND9.2.2 recently due to a security advisory.
+BIND is five components.
+</P>
+<OL>
+<LI>
+named
+</LI>
+<LI>
+dnssec-*
+</LI>
+<LI>
+client side resolver libraries
+</LI>
+<LI>
+client side utility libraries
+I thought there were lib and named parts to dnsssec...
+</LI>
+<LI>
+dynamic DNS update utilities
+</LI>
+</OL>
+<P>
+The only piece that we need for *building* is #4. That's the only part that has to be on the build host.
+What is the difference between resolver and util libs?
+If you want to edit testing/baseconfigs/all/etc/bind, you'll need a snapshot version.
+The resolver library contains the resolver.
+FreeS/WAN has its own copy of that in lib/liblwres.
+</P>
+<H2>Steps to Install UML for FreeS/WAN</H2>
+<OL>
+<LI> Get the following files:
+<OL type="a">
+<LI> from <A HREF="http://www.sandelman.ottawa.on.ca/freeswan/uml/">http://www.sandelman.ottawa.on.ca/freeswan/uml/</A>
+umlfreeroot-15.1.tar.gz (or highest numbered one). This is a
+  debian potato root file system. You can use this even on a Redhat
+  host, as it has the newer GLIBC2.2 libraries as well. 
+
+
+<!-- If you are using
+  Redhat 7.2 or newer as your development machine, you can create the
+  image from your installation media. See <A HREF="uml-rhroot.html">Building a RedHat root"></A>.
+  A future document will explain how to build this from .DEB files as well.
+-->
+
+<!--
+<LI> umlfreesharemini.tar.gz    (or umlfreeshareall.tar.gz). 
+  If you are a Debian potato user, you don't need it you can use your
+  native /usr/share.
+</UL>
+-->
+
+<LI> From <A HREF="ftp://ftp.xs4all.nl/pub/crypto/freeswan/">ftp://ftp.xs4all.nl/pub/crypto/freeswan/</A>
+a snapshot or release (1.92 or better)
+
+<LI> From a
+  <A HREF="http://www.kernel.org/mirrors/">http://www.kernel.org mirror</A>,
+  the virgin 2.4.19 kernel. Please realize that we have defaults in our
+  tree for kernel configuration. We try to track the latest UML
+  kernels. If you   use a newer kernel, you may have faults in the
+  kernel build process. You can see what the latest that is being regularly tested by visiting <A HREF="http://bugs.freeswan.org:81/regress/HEAD/lastgood/freeswan-regress-env.sh">freeswan-regress-env.sh</A>.
+
+<LI>
+<!-- Note: this step is refered to as "step 1d" below. -->
+Get
+  <A HREF="http://ftp.nl.linux.org/uml/">http://ftp.nl.linux.org/uml/</A>
+  uml-patch-2.4.19-47.bz2 or the one associated with your kernel.
+  As of 2003/03/05, uml-patch-2.4.19-47.bz2 works for us.
+<STRONG>More recent versions of the patch have not been tested by us.</STRONG>
+<LI> You'll probably want to visit 
+<A
+  HREF="http://user-mode-linux.sourceforge.net">http://user-mode-linux.sourceforge.net</A> 
+and get the UML utilities. These are not needed for the build or interactive use (but recommended). They are necessary for the regression testing procedures used by "make check". 
+We currently use uml_utilities_20020212.tar.bz2.
+<LI>
+You need tcpdump version 3.7.1 or better.
+This is newer than the version included in most LINUX distributions.
+You can check the version of an installed tcpdump with the --version flag.
+If you need a newer tcpdump
+fetch both tcpdump and libpcap source tar files from 
+<A HREF="http://www.tcpdump.org/">http://www.tcpdump.org/</A> or a mirror.
+</OL>
+
+<LI> Pick a suitable place, and extract the following files:
+<OL type="a"> 
+<LI>
+<!-- Note: this step is refered to as "step 2a" later. -->
+2.4.19 kernel. For instance:
+<PRE>
+<CODE>
+           cd /c2/kernel
+           tar xzvf ../download/pub/linux/kernel/v2.4/linux-2.4.19.tar.gz
+</CODE>
+</PRE>
+
+<LI> extract the umlfreeroot file 
+<!-- (unless you <A HREF="uml-rhroot.html">built your own from RPMs</A>) -->
+<PRE>
+<CODE>
+           mkdir -p /c2/user-mode-linux/basic-root
+           cd /c2/user-mode-linux/basic-root
+           tar xzvf ../download/umlfreeroot-15.1.tar.gz
+</CODE>
+</PRE>
+
+<LI> FreeSWAN itself (or checkout "all" from CVS)
+<PRE>
+<CODE>
+           mkdir -p /c2/freeswan/sandbox
+           cd /c2/freeswan/sandbox
+           tar xzvf ../download/snapshot.tar.gz
+</CODE>
+</PRE>
+</OL>
+
+<LI> If you need to build a newer tcpdump:
+<UL>
+<LI>
+Make sure you have OpenSSL installed -- it is needed for cryptographic routines.
+<LI>
+Unpack libpcap and tcpdump source in parallel directories (the tcpdump
+build procedures look for libpcap next door).
+<LI>
+Change directory into the libpcap source directory and then build the library:
+<PRE>
+<CODE>
+	./configure
+	make
+</CODE>
+</PRE>
+<LI>
+Change into the tcpdump source directory, build tcpdump, and install it.
+<PRE>
+<CODE>
+	./configure
+	make
+	# Need to be superuser to install in system directories.
+	# Installing in ~/bin would be an alternative.
+	su -c "make install"
+</CODE>
+</PRE>
+</UL>
+<LI> If you need the uml utilities, unpack them somewhere then build and install
+them:
+<PRE>
+<CODE>
+	cd tools
+	make all
+	# Need to be superuser to install in system directories.
+	# Installing in ~/bin would be an alternative.
+	su -c "make install BIN_DIR=/usr/local/bin"
+</CODE>
+</PRE>
+<LI> set up the configuration file
+<UL>
+<LI>
+<CODE>
+cd /c2/freeswan/sandbox/freeswan-1.97/testing/utils
+</CODE>
+<LI> copy umlsetup-sample.sh to ../../umlsetup.sh:
+<CODE>
+  cp umlsetup-sample.sh ../../umlsetup.sh
+</CODE>
+
+<LI> open up ../../umlsetup.sh in your favorite editor.
+<LI> change POOLSPACE= to point to the place with at least 500Mb of
+disk. Best if it is on the same partition as the "umlfreeroot" extraction,
+as it will attempt to use hard links if possible to save  disk space.
+
+<LI> Set TESTINGROOT if you intend to run the script outside of the
+     sandbox/snapshot/release directory. Otherwise, it will configure itself.
+
+<LI> KERNPOOL should point to the directory with your 2.4.19 kernel
+   tree. This tree should be unconfigured! This is the directory
+   you used in step 2a.
+
+<LI> UMLPATCH should point at the bz2 file you downloaded at 1d.
+   If using a kernel that already includes the patch, set this to /dev/null.
+ 
+<LI> FREESWANDIR should point at the directory where you unpacked
+               the snapshot/release. Include the "freeswan-snap2001sep16b"
+               or whatever in it. If you are running from CVS, then
+               you point at the directory where top, klips, etc. are.
+               The script will fix up the directory so that it can be
+               used.
+
+<LI> BASICROOT should be set to the directory used in 2b, or to the directory
+  that you created with RPMs.
+
+<LI> SHAREDIR should be set to the directory used in 2c, to /usr/share
+             for Debian potato users, or to $BASICROOT/usr/share.
+</UL>
+
+<LI> <PRE><CODE>
+cd $TESTINGROOT/utils
+sh make-uml.sh
+</CODE></PRE>
+    It will grind for awhile. If there are errors it will bail.
+    If so, run it under "script" and send the output to bugs@lists.freeswan.org.  
+
+<LI> You will have a bunch of stuff under $POOLSPACE.
+    Open four xterms:
+
+<PRE><CODE>
+    for i in sunrise sunset east west
+    do
+        xterm -name $i -title $i -e $POOLSPACE/$i/start.sh &
+    done
+</CODE></PRE>
+
+<LI> Login as root. Password is "root"
+    (Note, these virtual machines are networked together, but are not
+    configured to talk to the rest of the world.)
+
+<LI> verify that pluto started on east/west, run "ipsec look"
+
+<LI> login to sunrise. run "ping sunset"
+
+<LI> login to west. run "tcpdump -p -i eth1 -n"
+    (tcpdump must be version 3.7.1 or newer)
+
+<LI> Closing a console xterm will shut down that UML.
+
+<LI> You can "make check", if you want to.
+It is run from /c2/freeswan/sandbox/freeswan-1.97.</LI>
+
+</OL>
+
+<H1>Debugging the kernel with GDB</H1>
+
+<P>
+With User-Mode-Linux, you can debug the kernel using GDB.
+See <HREF="http://user-mode-linux.sourceforge.net/debugging.html">http://user-mode-linux.sourceforge.net/debugging.html</A>.
+</P>
+
+<P>
+Typically, one will want to address a test case for a failing situation.
+Running GDB from Emacs, or from other front ends is possible. First start GDB.
+</P>
+<P>
+Tell it to open the UMLPOOL/swan/linux program.
+</P>
+<P>
+Note the PID of GDB:
+<PRE>
+marajade-[projects/freeswan/mgmt/planning] mcr 1029 %ps ax | grep gdb
+ 1659 pts/9    SN     0:00 /usr/bin/gdb -fullname -cd /mara4/freeswan/kernpatch/UMLPOOL/swan/ linux
+</PRE>
+</P>
+
+<P>
+Set the following in the environment:
+<PRE>
+UML_east_OPT="debug gdb-pid=1659"
+</PRE>
+</P>
+
+<P>
+Then start the user-mode-linux in the test scheme you wish:
+<PRE>
+marajade-[kernpatch/testing/klips/east-icmp-02] mcr 1220 %../../utils/runme.sh
+</PRE>
+
+The user-mode-linux will stop on boot, giving you a chance to attach to the process:
+
+<PRE>
+(gdb) file linux
+Reading symbols from linux...done.
+(gdb) attach 1
+Attaching to program: /mara4/freeswan/kernpatch/UMLPOOL/swan/linux, process 1
+0xa0118bc1 in kill () at hostfs_kern.c:770
+</PRE>
+
+<P>
+At this point, break points should be created as appropriate.
+</P>
+
+<H2>Other notes about debugging</H2>
+
+<P>
+If you are running a standard test, after all the packets are sent, the UML will
+be shutdown. This can cause problems, because the UML may get terminated while you
+are debugging.
+</P>
+<P>
+The environment variable <CODE>NETJIGWAITUSER</CODE> can be set to "waituser".
+If so, then the testing system will prompt before exiting the test.
+</P>
+
+<H1>User-Mode-Linux mysteries</H1>
+
+<UL>
+<LI> running more than one UML of the same name (e.g. "west") can cause
+  problems.
+<LI> running more than one UML from the same root file system is not
+  a good idea.
+<LI> all this means that running "make check" twice on the same machine
+  is probably not a good idea.
+<LI> occationally, UMLs will get stuck. This can happen like:
+<BLOCK>
+15134 ?        T      0:00 /spare/hugh/uml/uml2.4.18-sept5/umlbuild/east/linux (east) [/bin/sh]           
+15138 ?        T      0:00 /spare/hugh/uml/uml2.4.18-sept5/umlbuild/east/linux (east) [halt]              
+ </BLOCK>
+
+these will need to be killed. Note that they are in "T"racing mode.
+<LI> UMLs can also hang, and will report "Tracing myself and I can't get out".
+This is a bug in UML. There are ways to find out what is going on and
+report this to the UML people, but we don't know the magic right now.
+</UL>
+
+<H1>Getting more info from uml_netjig</H1>
+
+<P>
+uml_netjig can be compiled with a built-in tcpdump. This uses not-yet-released
+code from <A HREF="http://www.tcpdump.org/">www.tcpdump.org</A>.
+Please see the instructions in <CODE>testing/utils/uml_netjig/Makefile</CODE>.
+</P>
+
+</body>
+</html>
diff --git a/doc/src/upgrading.html b/doc/src/upgrading.html
new file mode 100644
index 000000000..0d6401b96
--- /dev/null
+++ b/doc/src/upgrading.html
@@ -0,0 +1,260 @@
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>Introduction to FreeS/WAN</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, encryption, cryptography, FreeS/WAN, FreeSWAN">
+  <!--
+
+  Written by Claudia Schmeing for the Linux FreeS/WAN project
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: upgrading.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+
+<body>
+<A NAME="upgrading"></A><h1>Upgrading to FreeS/WAN 2.x</h1>
+
+
+<H2>New! Built in Opportunistic connections</H2>
+
+<P>Out of the box, FreeS/WAN 2.x will attempt to encrypt all your IP traffic.
+It will try to establish IPsec connections for:</P>
+<UL><LI>
+IP traffic from the Linux box on which you have installed FreeS/WAN, and</LI>
+<LI>
+outbound IP traffic routed through that Linux box (eg. from a protected subnet).</LI>
+</UL>
+<P>FreeS/WAN 2.x uses <STRONG>hidden, automatically enabled 
+ <VAR>ipsec.conf</VAR> connections</STRONG> to do this.</P>
+
+<P>This behaviour is part of our campaign to get Opportunistic 
+Encryption (OE) widespread in the Linux world, so that any two Linux boxes can
+encrypt to one another without prearrangement.
+There's one catch, however: you must <A HREF="quickstart.html#quickstart">set 
+up a few DNS records</A> 
+to distribute RSA public keys and (if applicable) IPsec gateway
+information.</P>
+
+<P>If you start FreeS/WAN before you have set up these DNS 
+records, your connectivity will be slow, and 
+messages relating to the built in connections will clutter your logs.
+If you are unable to set up DNS for OE, you will wish to 
+<A HREF="policygroups.html#disable_policygroups">disable the 
+hidden connections</A>.</P>
+
+<A NAME="upgrading.flagday"></A>
+
+<H3>Upgrading Opportunistic Encryption
+to 2.01 (or later)</H3>
+
+<P>As of FreeS/WAN 2.01, Opportunistic Encryption (OE)
+uses DNS TXT resource records (RRs) only (rather than TXT with KEY). 
+This change causes a "flag day". 
+Users of FreeS/WAN 2.00 (or earlier) OE who are upgrading may
+need to post additional resource records.
+</P>
+
+<P>If you are running 
+<A HREF="glossary.html#initiate-only">initiate-only OE</A>, 
+you <em>must</em> put up a TXT record in any forward domain as per our 
+<A HREF="quickstart.html#opp.client">quickstart instructions</A>. This
+replaces your old forward KEY.
+</P>
+
+<P>
+If you are running full OE, you require no updates. You already have 
+the needed TXT record in the reverse domain. 
+However, to facilitate future features, you
+may also wish to publish that TXT record in a forward domain as 
+instructed <A HREF="quickstart.html#opp.incoming">here</A>.
+</P>
+
+<P>If you are running OE on a gateway (and encrypting on behalf of subnetted
+boxes) you require no updates. 
+You already have the required TXT record in your gateway's reverse map,
+and the TXT records for any subnetted boxes require no updating.
+However, to facilitate future features, you may wish to publish your gateway's
+ TXT record in a forward domain as shown 
+<A HREF="quickstart.html#opp.incoming">here</A>.
+
+
+<P>
+During the transition, you may wish to leave any old KEY records up for
+some time. They will provide limited backward compatibility. 
+<!--
+For more
+detail on that compatibility, see <A HREF="oe.known-issues">Known Issues with
+OE</A>.
+-->
+</P>
+
+<H2>New! Policy Groups</H2>
+
+<P>We want to make it easy for you to declare security policy as it
+applies to IPsec connections.</P>
+
+<P>Policy Groups make it simple to say:
+</P>
+
+<UL>
+<LI>These are the folks I want to talk to in the clear.</LI>
+<LI>These spammers' domains -- I don't want to talk to them at all.</LI>
+<LI>To talk to the finance department, I must use IPsec.</LI>
+<LI>For any other communication, try to encrypt, but it's okay if we can't.</LI></UL>
+
+<P>FreeS/WAN then implements these policies, creating OE connections
+if and when needed.
+You can use Policy Groups along with connections you explicitly 
+define in ipsec.conf.</P>
+
+<P>For more information, see our
+<A HREF="policygroups.html">Policy Group HOWTO</A>.</P>
+
+
+<H2>New! Packetdefault Connection</H2>
+
+<P>Free/SWAN 2.x ships with the <STRONG>automatically enabled, hidden
+connection</STRONG> <VAR>packetdefault</VAR>. This configures
+a FreeS/WAN box as an OE gateway for any hosts located
+behind it. As mentioned above, you must configure some 
+<A HREF="quickstart.html">DNS records</A> for 
+OE to work.</P>
+<P>As the name implies, this connection functions as a default. If you
+have more specific connections, such as policy groups which configure 
+your FreeS/WAN box as an OE gateway for a local subnet, these 
+will apply before <VAR>packetdefault</VAR>. You can view 
+<VAR>packetdefault</VAR>'s specifics in 
+<A HREF="manpage.d/ipsec.conf.5.html">man ipsec.conf</A>.
+</P>
+
+
+<H2>FreeS/WAN now disables Reverse Path Filtering</H2>
+
+<P>FreeS/WAN often doesn't work with reverse path filtering. At
+start time, FreeS/WAN now turns rp_filter off, and logs a warning.</P>
+
+<P>FreeS/WAN does not turn it back on again. 
+You can do this yourself with a command like:</P>
+
+<PRE>   echo 1 > /proc/sys/net/ipv4/conf/eth0/rp_filter</PRE>
+
+<P>For eth0, substitute the interface which FreeS/WAN was affecting.</P>
+
+
+<A NAME="ipsec.conf_v2"></A><H2>Revised <VAR>ipsec.conf</VAR></H2>
+
+<H3>No promise of compatibility</H3>
+
+<P>The FreeS/WAN team promised config-file compatibility throughout
+the 1.x series. That means a 1.5 config file can be directly imported into
+a fresh 1.99 install with no problems.</P>
+
+<P>With FreeS/WAN 2.x, we've given ourselves permission to make the config
+file easier to use. The cost: some FreeS/WAN 1.x configurations will not
+work properly. Many of the new features are, however, backward compatible.</P>
+
+
+<H3>Most <VAR>ipsec.conf</VAR> files will work fine</H3>
+
+<P>... so long as you paste this line, <STRONG>with no preceding 
+whitespace</STRONG>,
+ at the top of your config file:
+</P>
+
+<PRE>    version 2</PRE>
+
+<H3>Backward compatibility patch</H3>
+
+<P>If the new defaults bite you, use 
+<A HREF="ipsec.conf.2_to_1">
+this <VAR>ipsec.conf</VAR> fragment</A> to simulate the old default values.</P>
+
+
+<H3>Details</H3>
+
+<P>
+We've obsoleted various directives which almost no one was using:
+</P>
+<PRE>    dump
+    plutobackgroundload
+    no_eroute_pass
+    lifetime
+    rekeystart
+    rekeytries</PRE>
+
+<P>For most of these, there is some other way to elicit the desired behaviour.
+See <A HREF="http://lists.freeswan.org/pipermail/design/2002-August/003243.html">
+this post</A>.
+
+<P>
+We've made some settings, which almost everyone was using, defaults.
+For example:
+</P>
+
+<PRE>    interfaces=%defaultroute
+    plutoload=%search
+    plutostart=%search
+    uniqueids=yes</PRE>
+
+<P>We've also changed some default values to help with OE and Policy Groups:</P>
+
+<PRE>    authby=rsasig   ## not secret!!!
+    leftrsasigkey=%dnsondemand ## looks up missing keys in DNS when needed.
+    rightrsasigkey=%dnsondemand</PRE>
+
+<P>
+Of course, you can still override any defaults by explictly declaring something
+else in your connection.
+</P>
+
+<P>  
+<A HREF="http://lists.freeswan.org/pipermail/design/2002-August/003243.html">A post with a list of many ipsec.conf changes.</A><BR>
+<A HREF="manpage.d/ipsec.conf.5.html">Current ipsec.conf manual.</A>
+</P>
+
+
+<A NAME="upgrading.rpms"></A><H3>Upgrading from 1.x RPMs to 2.x RPMs</H3>
+
+<P>Note: When upgrading from 1-series to 2-series RPMs, 
+<VAR>rpm -U</VAR> will not work.</P>
+
+<P>You must instead erase the 1.x RPMs, then install the 2.x set:</P>
+<PRE>    rpm -e freeswan</PRE>
+<PRE>    rpm -e freeswan-module</PRE>
+
+<P>On erasing, your old <VAR>ipsec.conf</VAR> should be moved to 
+<VAR>ipsec.conf.rpmsave</VAR>.
+Keep this. You will probably want to copy your existing connections to the 
+end of your new 2.x file.</P>
+
+<P>Install the RPMs suitable for your kernel version, such as:</P>
+<PRE>    rpm -ivh freeswan-module-2.04_2.4.20_20.9-0.i386.rpm</PRE>
+<PRE>    rpm -ivh freeswan-userland-2.04_2.4.20_20.9-0.i386.rpm</PRE>
+
+
+
+<P>Or, to splice the files:</P>
+
+<PRE>    cat /etc/ipsec.conf /etc/ipsec.conf.rpmsave > /etc/ipsec.conf.tmp
+    mv /etc/ipsec.conf.tmp /etc/ipsec.conf</PRE>
+
+<P>Then, remove the redundant <VAR>conn %default</VAR> and 
+<VAR>config setup</VAR>
+sections. Unless you have done any special configuring here, you'll likely
+want to remove the 1.x versions. Remove <VAR>conn OEself</VAR>, if
+present.</P>
+
+
+
+</body>
+</html>
diff --git a/doc/src/user_examples.html b/doc/src/user_examples.html
new file mode 100755
index 000000000..5e3784858
--- /dev/null
+++ b/doc/src/user_examples.html
@@ -0,0 +1,322 @@
+<html>
+<head>
+<title>FreeS/WAN examples</title>
+<meta name="keywords" content="Linux, IPsec, VPN, security, FreeSWAN, examples">
+
+<!--
+
+Written by Sandy Harris for the Linux FreeS/WAN project
+Freely distributable under the GNU General Public License
+
+More information at www.freeswan.org
+Feedback to users@lists.freeswan.org
+
+CVS information:
+RCS ID:          $Id: user_examples.html,v 1.1 2004/03/15 20:35:24 as Exp $
+Last changed:    $Date: 2004/03/15 20:35:24 $
+Revision number: $Revision: 1.1 $
+
+CVS revision numbers do not correspond to FreeS/WAN release numbers.
+-->
+</head>
+
+<body>
+
+<h1><a name="user.examples">FreeS/WAN script examples</a></h1>
+
+This file is intended to hold a collection of user-written example
+scripts or configuration files for use with FreeS/WAN.
+<p>
+So far it has only one entry.
+
+<h2><a name="poltorak">Poltorak's Firewall script</a></h2>
+
+<pre>
+From: Poltorak Serguei &lt;poltorak@dataforce.net&gt;
+Subject: [Users] Using FreeS/WAN
+Date: Tue, 16 Oct 2001
+
+Hello.
+
+I'm using FreeS/WAN IPsec for half a year. I learned a lot of things about
+it and I think it would be interesting for someone to see the result of my
+experiments and usage of FreeS/WAN. If you find a mistake in this
+file, please e-mail me. And excuse me for my english... I'm learning.. :)
+
+I'll talk about vary simple configuration:
+
+addresses prefix = 192.168
+
+    lan1          sgw1     .0.0/24 (Internet)       sgw2            lan2
+  .1.0/24---[ .1.1 ; .0.1 ]===================[ .0.10 ; . 2.10 ]---.2.0/24
+
+
+We need to let lan1 see lan2 across Internet like it is behind sgw1. The
+same for lan2. And we need to do IPX bridge for Novel Clients and NDS
+synchronization.
+
+my config:
+------------------- ipsec.conf -------------------
+conn lan1-lan2
+        type=tunnel
+        compress=yes
+        #-------------------
+        left=192.168.0.1
+        leftsubnet=192.168.1.0/24
+        #-------------------
+        right=192.168.0.10
+        rightsubnet=192.168.2.0/24
+        #-------------------
+        auth=esp
+        authby=secret
+--------------- end of ipsec.conf ----------------
+
+ping .2.x from .1.y   (y != 1)
+It works?? Fine. Let's continue...
+
+Why y != 1 ?? Because kernel of sgw1 have 2 IP addresses and it will choose
+the first IP (which is used to go to Internet) .0.1 and the packet won't go
+through IPsec tunnel :(  But if do ping on .1.1 kernel will respond from
+that address (.1.1) and the packet will be tunneled. The same problem occurred then
+.2.x sends a packet to .1.2 which is down at the moment. What happens? .1.1
+sends ARP requesting .1.2... after 3 tries it send to .2.x an destunreach,
+but from his "natural" IP or .0.1 . So the error message won't be delivered!
+It's a big problem...
+
+Resolution... One can manipulate with ipsec0 or ipsec0:0 to solve the
+problem (if ipsec0 has .1.1 kernel will send packets correctly), but there
+are powerful and elegant iproute2 :) We simply need to change source address
+of packet that goes to other secure lan. This is done with
+
+ip route replace 192.168.2.0/24 via 192.168.0.10 dev ipsec0 src 192.168.1.1
+
+Cool!! Now it works!!
+
+The second step. We want install firewall on sgw1 and sgw2. Encryption of 
+traffic without security isn't a good idea. I don't use {left|right}firewall, 
+because I'm running firewall from init scripts.
+
+We want IPsec data between lan1-lan2, some ICMP errors (destination
+unreachable, TTL exceeded, parameter problem and source quench), replying on 
+pings from both lans and Internet, ipxtunnel data for IPX and of course SSH
+between sgw1 and sgw2 and from/to one specified host.
+
+I'm using ipchains. With iptables there are some changes.
+
+---------------- rc.firewall ---------------------
+#!/bin/sh
+#
+# Firewall for IPsec lan1-lan2
+#
+
+IPC=/sbin/ipchains
+ANY=0.0.0.0/0
+
+# left
+SGW1_EXT=192.168.0.1
+SGW1_INT=192.168.1.1
+LAN1=192.168.1.0/24
+
+# right
+SGW2_EXT=192.168.0.10
+SGW2_INT=192.168.2.10
+LAN2=192.168.2.0/24
+
+# SSH from and to this host
+SSH_PEER_HOST=_SOME_HOST_
+
+# this is for left. exchange these values for right.
+MY_EXT=$SGW1_EXT
+MY_INT=$SGW1_INT
+PEER_EXT=$SGW2_EXT
+PEER_INT=$SGW2_INT
+INT_IF=eth1
+EXT_IF=eth0
+IPSEC_IF=ipsec0
+MY_LAN=$LAN1
+PEER_LAN=$LAN2
+
+$IPC -F
+$IPC -P input DENY
+$IPC -P forward DENY
+$IPC -P output DENY
+
+# Loopback traffic
+$IPC -A input -i lo -j ACCEPT
+$IPC -A output -i lo -j ACCEPT
+
+# for IPsec SGW1-SGW2
+## IKE
+$IPC -A input -p udp -s $PEER_EXT 500 -d $MY_EXT 500 -i $EXT_IF -j ACCEPT
+$IPC -A output -p udp -s $MY_EXT 500 -d $PEER_EXT 500 -i $EXT_IF -j ACCEPT
+## ESP
+$IPC -A input -p 50 -s $PEER_EXT -d $MY_EXT -i $EXT_IF -j ACCEPT
+### we don't need this line ### $IPC -A output -p 50 -s $MY_EXT -d $PEER_EXT -i $EXT_IF -j ACCEPT
+## forward LAN1-LAN2
+$IPC -A forward -s $MY_LAN -d $PEER_LAN -i $IPSEC_IF -j ACCEPT
+$IPC -A forward -s $PEER_LAN -d $MY_LAN -i $INT_IF -j ACCEPT
+$IPC -A output -s $PEER_LAN -d $MY_LAN -i $INT_IF -j ACCEPT
+$IPC -A input -s $PEER_LAN -d $MY_LAN -i $IPSEC_IF -j ACCEPT
+$IPC -A input -s $MY_LAN -d $PEER_LAN -i $INT_IF -j ACCEPT
+$IPC -A output -s $MY_LAN -d $PEER_LAN -i $IPSEC_IF -j ACCEPT
+
+# ICMP
+#
+## Dest unreachable
+### from/to Internet
+$IPC -A input -p icmp --icmp-type destination-unreachable -s $ANY -d $MY_EXT -i $EXT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type destination-unreachable -s $MY_EXT -d $ANY -i $EXT_IF -j ACCEPT
+### from/to Lan
+$IPC -A input -p icmp --icmp-type destination-unreachable -s $ANY -d $MY_INT -i $INT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type destination-unreachable -s $MY_INT -d $ANY -i $INT_IF -j ACCEPT
+### from/to Peer Lan
+$IPC -A input -p icmp --icmp-type destination-unreachable -s $ANY -d $MY_INT -i $IPSEC_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type destination-unreachable -s $MY_INT -d $ANY -i $IPSEC_IF -j ACCEPT
+#
+## Source quench
+### from/to Internet
+$IPC -A input -p icmp --icmp-type source-quench -s $ANY -d $MY_EXT -i $EXT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type source-quench -s $MY_EXT -d $ANY -i $EXT_IF -j ACCEPT
+### from/to Lan
+$IPC -A input -p icmp --icmp-type source-quench -s $ANY -d $MY_INT -i $INT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type source-quench -s $MY_INT -d $ANY -i $INT_IF -j ACCEPT
+### from/to Peer Lan
+$IPC -A input -p icmp --icmp-type source-quench -s $ANY -d $MY_INT -i $IPSEC_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type source-quench -s $MY_INT -d $ANY -i $IPSEC_IF -j ACCEPT
+#
+## Parameter problem
+### from/to Internet
+$IPC -A input -p icmp --icmp-type parameter-problem -s $ANY -d $MY_EXT -i $EXT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type parameter-problem -s $MY_EXT -d $ANY -i $EXT_IF -j ACCEPT
+### from/to Lan
+$IPC -A input -p icmp --icmp-type parameter-problem -s $ANY -d $MY_INT -i $INT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type parameter-problem -s $MY_INT -d $ANY -i $INT_IF -j ACCEPT
+### from/to Peer Lan
+$IPC -A input -p icmp --icmp-type parameter-problem -s $ANY -d $MY_INT -i $IPSEC_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type parameter-problem -s $MY_INT -d $ANY -i $IPSEC_IF -j ACCEPT
+#
+## Time To Live exceeded
+### from/to Internet
+$IPC -A input -p icmp --icmp-type time-exceeded -s $ANY -d $MY_EXT -i $EXT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type time-exceeded -s $MY_EXT -d $ANY -i $EXT_IF -j ACCEPT
+### to Lan
+$IPC -A input -p icmp --icmp-type time-exceeded -s $ANY -d $MY_INT -i $INT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type time-exceeded -s $MY_INT -d $ANY -i $INT_IF -j ACCEPT
+### to Peer Lan
+$IPC -A input -p icmp --icmp-type time-exceeded -s $ANY -d $MY_INT -i $IPSEC_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type time-exceeded -s $MY_INT -d $ANY -i $IPSEC_IF -j ACCEPT
+
+# ICMP PINGs
+## from Internet
+$IPC -A input -p icmp -s $ANY -d $MY_EXT --icmp-type echo-request  -i $EXT_IF -j ACCEPT
+$IPC -A output -p icmp -s $MY_EXT -d $ANY --icmp-type echo-reply  -i $EXT_IF -j ACCEPT
+## from LAN
+$IPC -A input -p icmp -s $ANY -d $MY_INT --icmp-type echo-request -i $INT_IF -j ACCEPT
+$IPC -A output -p icmp -s $MY_INT -d $ANY --icmp-type echo-reply  -i $INT_IF -j ACCEPT
+## from Peer LAN
+$IPC -A input -p icmp -s $ANY -d $MY_INT --icmp-type echo-request -i $IPSEC_IF -j ACCEPT
+$IPC -A output -p icmp -s $MY_INT -d $ANY --icmp-type echo-reply  -i $IPSEC_IF -j ACCEPT
+
+# SSH
+## from SSH_PEER_HOST
+$IPC -A input -p tcp -s $SSH_PEER_HOST -d $MY_EXT 22 -i $EXT_IF -j ACCEPT
+$IPC -A output -p tcp \! -y -s $MY_EXT 22 -d $SSH_PEER_HOST -i $EXT_IF -j ACCEPT
+## to SSH_PEER_HOST
+$IPC -A input -p tcp \! -y -s $SSH_PEER_HOST 22 -d $MY_EXT -i $EXT_IF -j ACCEPT
+$IPC -A output -p tcp -s $MY_EXT -d $SSH_PEER_HOST 22 -i $EXT_IF -j ACCEPT
+## from PEER
+$IPC -A input -p tcp -s $PEER_EXT -d $MY_EXT 22 -i $EXT_IF -j ACCEPT
+$IPC -A output -p tcp \! -y -s $MY_EXT 22 -d $PEER_EXT -i $EXT_IF -j ACCEPT
+## to PEER
+$IPC -A input -p tcp \! -y -s $PEER_EXT 22 -d $MY_EXT -i $EXT_IF -j ACCEPT
+$IPC -A output -p tcp -s $MY_EXT -d $PEER_EXT 22 -i $EXT_IF -j ACCEPT
+
+# ipxtunnel
+$IPC -A input -p udp -s $PEER_INT 2005 -d $MY_INT 2005 -i $IPSEC_IF -j ACCEPT
+$IPC -A output -p udp -s $MY_INT 2005 -d $PEER_INT 2005 -i $IPSEC_IF -j ACCEPT
+
+---------------- end of rc.firewall ----------------------
+
+To understand this we need to look on this scheme:
+
+           ++-----------------------&lt;----------------------------+
+           || ipsec0                                             |
+           \/                                                    |
+ eth0  +--------+    /---------/ yes  /---------/ yes +-----------------------+
+------&gt;| INPUT  |--&gt;/ ?local? /-----&gt;/ ?IPsec? /-----&gt;| decrypt & decapsulate |
+ eth1  +--------+  /---------/      /---------/       +-----------------------+
+                       || no            || no
+                       \/               \/
+                  +----------+      +---------+        +-------+
+                  | routing  |      |  local  |        | local |
+                  | decision |      | deliver |        | send  |
+                  +----------+      +---------+        +-------+
+                       ||                                 ||
+                       \/                                 \/
+                   +---------+                       +----------+
+                   | forward |                       | routing  |
+                   +---------+                       | decision |
+                       ||                            +----------+
+                       ||                                  ||
+                       ++----------------&lt;-----------------++
+                       ||
+                       \/
+                   +--------+ eth0
+                   | OUTPUT | eth1
+                   +--------+ ipsec0
+                       ||
+                       \/
+                   /---------/ yes +-----------------------+
+                  / ?IPsec? /-----&gt;| encrypt & encapsulate |
+                 /---------/       +-----------------------+
+                      || no                    ||
+                      ||                       ||
+                      ||                       \/   eth0, eth1
+                      ++-----------------------++--------------&gt;
+
+This explain how a packet traverse TCP/IP stack in IPsec capable kernel.
+
+FIX ME, please, if there are any errors
+
+Test the new firewall now.
+
+
+Now about IPX. I tried 3 programs for tunneling IPX: tipxd, SIB and ipxtunnel
+
+tipxd didn't send packets.. :(
+SIB and ipxtunnel worked fine :)
+With ipxtunnel there was a little problem. In sources there are an error.
+
+--------------------- in main.c ------------------------
+&lt;       bytes += p.len;
+---
+&gt;       bytes += len;
+--------------------------------------------------------
+
+After this FIX everything goes right...
+
+------------------- /etc/ipxtunnel.conf ----------------
+port    2005
+remote  192.168.101.97    2005
+interface eth1
+--------------- end of /etc/ipxtunnel.conf -------------
+
+I use IPX tunnel between .1.1 and .2.10 so we don't need to encrypt nor
+authenticate encapsulated IPX packets, it is done with IPsec.
+
+If you don't wont to use iproute2 to change source IP you need to use SIB
+(it is able to bind local address) or establish tunnel between .0.1 and
+.0.10 (external IPs, you need to do encryption in the program, but it isn't
+strong).
+
+For now I'm using ipxtunnel.
+
+I think that's all for the moment. If there are any error, please e-mail me: 
+poltorak@df.ru . It would be cool if someone puts the scheme of TCP/IP in
+kernel and firewall example on FreeS/WAN's manual pages.
+
+PoltoS
+</pre>
+
+</body>
+</html>
\ No newline at end of file
diff --git a/doc/src/web.html b/doc/src/web.html
new file mode 100644
index 000000000..19df6ffa6
--- /dev/null
+++ b/doc/src/web.html
@@ -0,0 +1,905 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
+    "http://www.w3.org/TR/html4/loose.dtd">
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html">
+  <title>FreeS/WAN web links</title>
+  <meta name="keywords"
+  content="Linux, IPsec, VPN, security, FreeSWAN, links, web">
+  <!--
+
+  Written by Sandy Harris for the Linux FreeS/WAN project
+  Freely distributable under the GNU General Public License
+
+  More information at www.freeswan.org
+  Feedback to users@lists.freeswan.org
+
+  CVS information:
+  RCS ID:          $Id: web.html,v 1.1 2004/03/15 20:35:24 as Exp $
+  Last changed:    $Date: 2004/03/15 20:35:24 $
+  Revision number: $Revision: 1.1 $
+
+  CVS revision numbers do not correspond to FreeS/WAN release numbers.
+  -->
+</head>
+
+<body>
+<h1><a name="weblink">Web links</a></h1>
+
+<h2><a name="freeswan">The Linux FreeS/WAN Project</a></h2>
+
+<p>The main project web site is <a
+href="http://www.freeswan.org/">www.freeswan.org</a>.</p>
+
+<p>Links to other project-related <a href="intro.html#sites">sites</a> are
+provided in our introduction section.</p>
+
+<h3><a name="patch">Add-ons and patches for FreeS/WAN</a></h3>
+
+<p>Some user-contributed patches have been integrated into the FreeS/WAN
+distribution. For a variety of reasons, those listed below have not.</p>
+
+<p>Note that not all patches are a good idea.</p>
+<ul>
+  <li>There are a number of "features" of IPsec which we do not implement
+    because they reduce security. See this <a
+    href="compat.html#dropped">discussion</a>. We do not recommend using
+    patches that implement these. One example is aggressive mode.</li>
+  <li>We do not recommend adding "features" of any sort unless they are
+    clearly necessary, or at least have clear benefits. For example,
+    FreeS/WAN would not become more secure if it offerred a choice of 14
+    ciphers. If even one was flawed, it would certainly become less secure
+    for anyone using that cipher. Even with 14 wonderful ciphers, it would be
+    harder to maintain and administer, hence more vulnerable to various human
+    errors.</li>
+</ul>
+
+<p>This is not to say that patches are necessarily  bad, only that using them
+requires some deliberation. For example, there might be perfectly good
+reasons to add a specific cipher in your application: perhaps GOST to comply
+with government standards in Eastern Europe, or AES for performance
+benefits.</p>
+
+<h4>Current patches</h4>
+
+<p>Patches believed current::</p>
+<ul>
+  <li>patches for <a href="http://www.strongsec.com/freeswan/">X.509
+    certificate support</a>, also available from a <a
+    href="http://www.twi.ch/~sna/strongsec/freeswan/">mirror site</a></li>
+  <li>patches to add <a href="http://www.irrigacion.gov.ar/juanjo/ipsec">AES
+    and other ciphers</a>. There is preliminary data indicating AES gives a
+    substantial <a href="performance.html#perf.more">performance
+  gain</a>.</li>
+</ul>
+
+<p>There is also one add-on that takes the form of a modified FreeS/WAN
+distribution, rather than just patches to the standard distribution:</p>
+<ul>
+  <li><a href="http://www.ipv6.iabg.de/downloadframe/index.html">IPv6
+    support</a></li>
+</ul>
+
+<p>Before using any of the above,, check the <a href="mail.html">mailing
+lists</a> for news of newer versions and to see whether they have been
+incorporated into more recent versions of FreeS/WAN.</p>
+
+<h4>Older patches</h4>
+<ul>
+  <li><a href="http://sources.colubris.com/en/projects/FreeSWAN/">hardware
+    acceleration</a></li>
+  <li>a <a href="http://tzukanov.narod.ru/">series</a> of patches that
+    <ul>
+      <li>provide GOST, a Russian gov't. standard cipher, in MMX
+      assembler</li>
+      <li>add GOST to OpenSSL</li>
+      <li>add GOST to the International kernel patch</li>
+      <li>let FreeS/WAN use International kernel patch ciphers</li>
+    </ul>
+  </li>
+  <li>Neil Dunbar's patches for <a
+    href="ftp://hplose.hpl.hp.com/pub/nd/pluto-openssl.tar.gz">certificate
+    support</a>, using code from <a href="http://www.openssl.org">Open
+    SSL</a>.</li>
+  <li>Luc Lanthier's <a
+    href="ftp://ftp.netwinder.org/users/f/firesoul/">patches</a> for <a
+    href="glossary.html#PKIX">PKIX</a> support.</li>
+  <li><a href="ftp://ftp.heise.de/pub/ct/listings/9916-180.tgz">patches</a>
+    to add <a href="glossary.html#blowfish">Blowfish</a>, <a
+    href="glossary.html#IDEA">IDEA</a> and <a
+    href="glossary.html#CAST128">CAST-128</a> to FreeS/WAN</li>
+  <li>patches for FreeS/WAN 1.3, Pluto support for <a
+    href="http://alcatraz.webcriminals.com/~bastiaan/ipsec/">external
+    authentication</a>, for example with a smartcard or SKEYID.</li>
+  <li><a href="http://www.zengl.net/freeswan/download/">patches and
+    utilities</a> for using FreeS/WAN with PGPnet</li>
+  <li><a
+    href="http://www.freelith.com/lithworks/crypto/freeswan_patch.htm">Blowfish
+    encryption and Tiger hash</a></li>
+  <li><a
+    href="http://www.cendio.se/~bellman/aggressive-pluto.snap.tar.gz">patches</a>
+    for aggressive mode support</li>
+</ul>
+
+<p>These patches are for older versions of FreeS/WAN and will likely not work
+with the current version.  Older versions of FreeS/WAN may be available on
+some of the <a href="intro.html#sites">distribution sites</a>, but we
+recommend using the current release.</p>
+
+<h4><a name="VPN.masq">VPN masquerade patches</a></h4>
+
+<p>Finally, there are some patches to other code that may be useful with
+FreeS/WAN:</p>
+<ul>
+  <li>a <a
+    href="ftp://ftp.rubyriver.com/pub/jhardin/masquerade/ip_masq_vpn.html">patch</a>
+    to make IPsec, PPTP and SSH VPNs work through a Linux firewall with <a
+    href="glossary.html#masq">IP masquerade</a>.</li>
+  <li><a href="http://www.linuxdoc.org/HOWTO/VPN-Masquerade-HOWTO.html">Linux
+    VPN Masquerade HOWTO</a></li>
+</ul>
+
+<p>Note that this is not required if the same machine does IPsec and
+masquerading, only if you want a to locate your IPsec gateway on a
+masqueraded network. See our <a href="firewall.html#NAT">firewalls</a>
+document for discussion of why this is problematic.</p>
+
+<p>At last report, this patch could not co-exist with FreeS/WAN on the same
+machine.</p>
+
+<h3><a name="dist">Distributions including FreeS/WAN</a></h3>
+
+<p>The introductory section of our document set lists several <a
+href="intro.html#distwith">Linux distributions</a> which include
+FreeS/WAN.</p>
+
+<h3><a name="used">Things FreeS/WAN uses or could use</a></h3>
+<ul>
+  <li><a href="http://openpgp.net/random">/dev/random</a> support page,
+    discussion of and code for the Linux <a
+    href="glossary.html#random">random number driver</a>. Out-of-date when we
+    last checked (January 2000), but still useful.</li>
+  <li>other programs related to random numbers:
+    <ul>
+      <li><a href="http://www.mindrot.org/audio-entropyd.html">audio entropy
+        daemon</a> to gather noise from a sound card and feed it into
+        /dev/random</li>
+      <li>an <a href="http://www.lothar.com/tech/crypto/">entropy-gathering
+        daemon</a></li>
+      <li>a driver for the random number generator in recent <a
+        href="http://sourceforge.net/projects/gkernel/">Intel chipsets</a>.
+        This driver is included as standard in 2.4 kernels.</li>
+    </ul>
+  </li>
+  <li>a Linux <a href="http://www.marko.net/l2tp/">L2TP Daemon</a> which
+    might be useful for communicating with Windows 2000 which builds L2TP
+    tunnels over its IPsec connections</li>
+  <li>to use opportunistic encryption, you need a recent version of <a
+    href="glossary.html#BIND">BIND</a>. You can get one from the <a
+    href="http://www.isc.org">Internet Software Consortium</a> who maintain
+    BIND.</li>
+</ul>
+
+<h3><a name="alternatives">Other approaches to VPNs for Linux</a></h3>
+<ul>
+  <li>other Linux <a href="#linuxipsec">IPsec implementations</a></li>
+  <li><a href="http://www.tik.ee.ethz.ch/~skip/">ENskip</a>, a free
+    implementation of Sun's <a href="glossary.html#SKIP">SKIP</a>
+  protocol</li>
+  <li><a href="http://sunsite.auc.dk/vpnd/">vpnd</a>, a non-IPsec VPN daemon
+    for Linux which creates tunnels using <a
+    href="glossary.html#Blowfish">Blowfish</a> encryption</li>
+  <li><a href="http://www.winton.org.uk/zebedee/">Zebedee</a>, a simple GPLd
+    tunnel-building program with Linux and Win32 versions. The name is from
+    <strong>Z</strong>lib compression, <strong>B</strong>lowfish encryption
+    and <strong>D</strong>iffie-Hellman key exchange.</li>
+  <li>There are at least two  PPTP implementations for Linux
+    <ul>
+      <li>Moreton Bay's <a
+        href="http://www.moretonbay.com/vpn/pptp.html">PoPToP</a></li>
+      <li><a
+        href="http://cag.lcs.mit.edu/~cananian/Projects/PPTP/">PPTP-Linux</a></li>
+    </ul>
+  </li>
+  <li><a href="http://sites.inka.de/sites/bigred/devel/cipe.html">CIPE</a>
+    (crypto IP encapsulation) project, using their own lightweight protocol
+    to encrypt between routers</li>
+  <li><a href="http://tinc.nl.linux.org/">tinc</a>, a VPN Daemon</li>
+</ul>
+
+<p>There is a list of <a
+href="http://www.securityportal.com/lskb/10000000/kben10000005.html">Linux
+VPN</a> software in the <a
+href="http://www.securityportal.com/lskb/kben00000001.html">Linux Security
+Knowledge Base</a>.</p>
+
+<h2><a name="ipsec.link">The IPsec Protocols</a></h2>
+
+<h3><a name="general">General IPsec or VPN information</a></h3>
+<ul>
+  <li>The <a href="http://www.vpnc.org">VPN Consortium</a> is a group for
+    vendors of IPsec products. Among other things, they have a good
+    collection of <a href="http://www.vpnc.org/white-papers.html">IPsec white
+    papers</a>.</li>
+  <li>A VPN mailing list with a <a
+    href="http://kubarb.phsx.ukans.edu/~tbird/vpn.html">home page</a>, a FAQ,
+    some product comparisons, and many links.</li>
+  <li><a href="http://www.opus1.com/vpn/index.html">VPN pointer page</a></li>
+  <li>a <a href="http://www.epm.ornl.gov/~dunigan/vpn.html">collection</a> of
+    VPN links, and some explanation</li>
+</ul>
+
+<h3><a name="overview">IPsec overview documents or slide sets</a></h3>
+<ul>
+  <li>the FreeS/WAN <a href="ipsec.html">document section</a> on these
+    protocols</li>
+</ul>
+
+<h3><a name="otherlang">IPsec information in languages other than
+English</a></h3>
+<ul>
+  <li><a
+    href="http://www.imib.med.tu-dresden.de/imib/Internet/Literatur/ipsec-docu.html">German</a></li>
+  <li><a href="http://www.kame.net/index-j.html">Japanese</a></li>
+  <li>Feczak Szabolcs' thesis in <a
+    href="http://feczo.koli.kando.hu/vpn/">Hungarian</a></li>
+  <li>Davide Cerri's thesis and some presentation slides <a
+    href="http://www.linux.it/~davide/doc/">Italian</a></li>
+</ul>
+
+<h3><a name="RFCs1">RFCs and other reference documents</a></h3>
+<ul>
+  <li><a href="rfc.html">Our document</a> listing the RFCs relevant to Linux
+    FreeS/WAN and giving various ways of obtaining both RFCs and Internet
+    Drafts.</li>
+  <li><a href="http://www.vpnc.org/vpn-standards.html">VPN Standards</a> page
+    maintained by <a href="glossary.html#VPNC">VPNC</a>. This covers both
+    RFCs and Drafts, and classifies them in a fairly helpful way.</li>
+  <li><a href="http://www.rfc-editor.org">RFC archive</a></li>
+  <li><a href="http://www.ietf.org/ids.by.wg/ipsec.html">Internet Drafts</a>
+    related to IPsec</li>
+  <li>US government <a href="http://www.itl.nist.gov/div897/pubs"> site</a>
+    with their <a href="glossary.html#FIPS">FIPS</a> standards</li>
+  <li>Archives of the ipsec@tis.com mailing list where discussion of drafts
+    takes place.
+    <ul>
+      <li><a href="http://www.sandelman.ottawa.on.ca/ipsec">Eastern
+      Canada</a></li>
+      <li><a href="http://www.vpnc.org/ietf-ipsec">California</a>.</li>
+    </ul>
+  </li>
+</ul>
+
+<h3><a name="analysis">Analysis and critiques of IPsec protocols</a></h3>
+<ul>
+  <li>Counterpane's <a
+    href="http://www.counterpane.com/ipsec.pdf">evaluation</a> of the
+    protocols</li>
+  <li>Simpson's <a
+    href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/1999/06/msg00319.html">IKE
+    Considered Dangerous</a> paper. Note that this is a link to an archive of
+    our mailing list. There are several replies in addition to the paper
+    itself.</li>
+  <li>Fate Labs <a href="http://www.fatelabs.com/loki-vpn.pdf">Virual Private
+    Problems: the Broken Dream</a></li>
+  <li>Catherine Meadows' paper <cite>Analysis of the Internet Key Exchange
+    Protocol Using the NRL Protocol Analyzer</cite>, in <a
+    href="http://chacs.nrl.navy.mil/publications/CHACS/1999/1999meadows-IEEE99.pdf">PDF</a>
+    or <a
+    href="http://chacs.nrl.navy.mil/publications/CHACS/1999/1999meadows-IEEE99.ps">Postscript</a>.</li>
+  <li>Perlman and Kaufmnan
+    <ul>
+      <li><a
+        href="http://snoopy.seas.smu.edu/ee8392_summer01/week7/perlman2.pdf">Key
+        Exchange in IPsec</a></li>
+      <li>a newer <a
+        href="http://sec.femto.org/wetice-2001/papers/radia-paper.pdf">PDF
+        paper</a>, <cite>Analysis of the IPsec Key Exchange
+      Standard</cite>.</li>
+    </ul>
+  </li>
+  <li>Bellovin's <a
+    href="http://www.research.att.com/~smb/papers/index.html">papers</a> page
+    including his:
+    <ul>
+      <li><cite>Security Problems in the TCP/IP Protocol Suite</cite>
+      (1989)</li>
+      <li><cite>Problem Areas for the IP Security Protocols</cite> (1996)</li>
+      <li><cite>Probable Plaintext Cryptanalysis of the IP Security
+        Protocols</cite> (1997)</li>
+    </ul>
+  </li>
+  <li>An <a href="http://www.lounge.org/ike_doi_errata.html">errata list</a>
+    for the IPsec RFCs.</li>
+</ul>
+
+<h3><a name="IP.background">Background information on IP</a></h3>
+<ul>
+  <li>An <a href="http://ipprimer.windsorcs.com/">IP tutorial</a> that seems
+    to be written mainly for Netware or Microsoft LAN admins entering a new
+    world</li>
+  <li><a href="http://www.iana.org">IANA</a>, Internet Assigned Numbers
+    Authority</li>
+  <li><a href="http://public.pacbell.net/dedicated/cidr.html">CIDR</a>,
+    Classless Inter-Domain Routing</li>
+  <li>Also see our <a href="biblio.html">bibliography</a></li>
+</ul>
+
+<h2><a name="implement">IPsec Implementations</a></h2>
+
+<h3><a name="linuxprod">Linux products</a></h3>
+
+<p>Vendors using FreeS/WAN in turnkey firewall or VPN products are listed in
+our <a href="intro.html#turnkey">introduction</a>.</p>
+
+<p>Other vendors have Linux IPsec products which, as far as we know, do not
+use FreeS/WAN</p>
+<ul>
+  <li><a href="http://www.redcreek.com/products/shareware.html">Redcreek</a>
+    provide an open source Linux driver for their PCI hardware VPN card. This
+    card has a 100 Mbit Ethernet port, an Intel 960 CPU plus more specialised
+    crypto chips, and claimed encryption performance of 45 Mbit/sec. The PC
+    sees it as an Ethernet board.</li>
+  <li><a href="http://linuxtoday.com/stories/8428.html?nn">Paktronix</a>
+    offer a Linux-based VPN with hardware encryption</li>
+  <li><a href="http://www.watchguard.com/">Watchguard</a> use Linux in their
+    Firebox product.</li>
+  <li><a href="http://www.entrust.com">Entrust</a> offer a developers'
+    toolkit for using their <a href="glossary.html#PKI">PKI</a> for IPsec
+    authentication</li>
+  <li>According to a report on our mailing list, <a
+    href="http://www.axent.com">Axent</a> have a Linux version of their
+    product.</li>
+</ul>
+
+<h3><a name="router">IPsec in router products</a></h3>
+
+<p>All the major router vendors support IPsec, at least in some models.</p>
+<ul>
+  <li><a href="http://www.cisco.com/warp/public/707/16.html">Cisco</a> IPsec
+    information</li>
+  <li>Ascend, now part of <a href="http://www.lucent.com/">Lucent</a>, have
+    some IPsec-based products</li>
+  <li><a href="http://www.nortelnetworks.com/">Bay Networks</a>, now part of
+    Nortel, use IPsec in their Contivity switch product line</li>
+  <li><a href="http://www.3com.com/products/enterprise.html">3Com</a> have a
+    number of VPN products, some using IPsec</li>
+</ul>
+
+<h3><a name="fw.web">IPsec in firewall products</a></h3>
+
+<p>Many firewall vendors offer IPsec, either as a standard part of their
+product, or an optional extra. A few we know about are:</p>
+<ul>
+  <li><a href="http://www.borderware.com/">Borderware</a></li>
+  <li><a href="http://www.ashleylaurent.com/vpn/ipsec_vpn.htm">Ashley
+    Laurent</a></li>
+  <li><a href="http://www.watchguard.com">Watchguard</a></li>
+  <li><a href="http://www.fx.dk/firewall/ipsec.html">Injoy</a> for OS/2</li>
+</ul>
+
+<p>Vendors using FreeS/WAN in turnkey firewall products are listed in our <a
+href="intro.html#turnkey">introduction</a>.</p>
+
+<h3><a name="ipsecos">Operating systems with IPsec support</a></h3>
+
+<p>All the major open source operating systems support IPsec. See below for
+details on <a href="#BSD">BSD-derived</a> Unix variants.</p>
+
+<p>Among commercial OS vendors, IPsec players include:</p>
+<ul>
+  <li><a
+    href="http://msdn.microsoft.com/isapi/msdnlib.idc?theURL=/library/backgrnd/html/msdn_ip_security.htm">Microsoft</a>
+    have put IPsec in their Windows 2000 and XP products</li>
+  <li><a
+    href="http://www.s390.ibm.com/stories/1999/os390v2r8_pr.html">IBM</a>
+    announce a release of OS390 with IPsec support via a crypto
+  co-processor</li>
+  <li><a
+    href="http://www.sun.com/solaris/ds/ds-security/ds-security.pdf">Sun</a>
+    include IPsec in Solaris 8</li>
+  <li><a
+    href="http://www.hp.com/security/products/extranet-security.html">Hewlett
+    Packard</a> offer IPsec for their Unix machines</li>
+  <li>Certicom have IPsec available for the <a
+    href="http://www.certicom.com/products/movian/movianvpn_tech.html">Palm</a>.</li>
+  <li>There were reports before the release that Apple's Mac OS X would have
+    IPsec support built in, but it did not seem to be there when we last
+    checked. If you find, it please let us know via the <a
+    href="mail.html">mailing list</a>.</li>
+</ul>
+
+<h3>IPsec on network cards</h3>
+
+<p>Network cards with built-in IPsec acceleration are available from at least
+Intel, 3Com and Redcreek.</p>
+
+<h3><a name="opensource">Open source IPsec implementations</a></h3>
+
+<h4><a name="linuxipsec">Other Linux IPsec implementations</a></h4>
+
+<p>We like to think of FreeS/WAN as <em>the</em> Linux IPsec implementation,
+but it is not the only one. Others we know of are:</p>
+<ul>
+  <li><a href="http://www.enst.fr/~beyssac/pipsec/">pipsecd</a>, a
+    lightweight implementation of IPsec for Linux. Does not require kernel
+    recompilation.</li>
+  <li>Petr Novak's <a href="ftp://ftp.eunet.cz/icz/ipnsec/">ipnsec</a>, based
+    on the OpenBSD IPsec code and using <a
+    href="glossary.html#photuris">Photuris</a> for key management</li>
+  <li>A now defunct project at <a
+    href="http://www.cs.arizona.edu/security/hpcc-blue/linux.html">U of
+    Arizona</a> (export controlled)</li>
+  <li><a href="http://snad.ncsl.nist.gov/cerberus">NIST Cerebus</a> (export
+    controlled)</li>
+</ul>
+
+<h4><a name="BSD">IPsec for BSD Unix</a></h4>
+<ul>
+  <li><a href="http://www.kame.net/project-overview.html">KAME</a>, several
+    large Japanese companies co-operating on IPv6 and IPsec</li>
+  <li><a href="http://web.mit.edu/network/isakmp">US Naval Research Lab</a>
+    implementation of IPv6 and of IPsec for IPv4 (export controlled)</li>
+  <li><a href="http://www.openbsd.org">OpenBSD</a> includes IPsec as a
+    standard part of the distribution</li>
+  <li><a href="http://www.r4k.net/ipsec">IPsec for FreeBSD</a></li>
+  <li>a <a href="http://www.netbsd.org/Documentation/network/ipsec/">FAQ</a>
+    on NetBSD's IPsec implementation</li>
+</ul>
+
+<h4><a name="misc">IPsec for other systems</a></h4>
+<ul>
+  <li><a href="http://www.tcm.hut.fi/Tutkimus/IPSEC/">Helsinki U of
+    Technolgy</a> have implemented IPsec for Solaris, Java and Macintosh</li>
+</ul>
+
+<h3><a name="interop.web">Interoperability</a></h3>
+
+<p>The IPsec protocols are designed so that different implementations should
+be able to work together. As they say "the devil is in the details". IPsec
+has a lot of details, but considerable success has been achieved.</p>
+
+<h4><a name="result">Interoperability results</a></h4>
+
+<p>Linux FreeS/WAN has been tested for interoperability with many other IPsec
+implementations. Results to date are in our <a
+href="interop.html">interoperability</a> section.</p>
+
+<p>Various other sites have information on interoperability between various
+IPsec implementations:</p>
+<ul>
+  <li><a href="http://www.opus1.com/vpn/atl99display.html">interop
+    results</a> from a bakeoff in Atlanta, September 1999.</li>
+  <li>a French company, HSC's, <a
+    href="http://www.hsc.fr/ressources/presentations/ipsec99/index.html.en">interoperability</a>
+    test data covers FreeS/WAN, Open BSD, KAME, Linux pipsecd, Checkpoint,
+    Red Creek Ravlin, and Cisco IOS</li>
+  <li><a href="http://www.icsa.net/">ICSA</a> offer certification programs
+    for various security-related products. See their list of <a
+    href="http://www.icsa.net/html/communities/ipsec/certification/certified_products/index.shtml">
+    certified IPsec</a> products. Linux FreeS/WAN is not currently on that
+    list, but several products with which we interoperate are.</li>
+  <li>VPNC have a page on why they are not yet doing <a
+    href="http://www.vpnc.org/interop.html">interoperability</a> testing and
+    a page on the <a href="http://www.vpnc.org/conformance.html">spec
+    conformance</a> testing that they are doing</li>
+  <li>a <a href="http://www.commweb.com/article/COM20000912S0009">review</a>
+    comparing a dozen commercial IPsec implemetations. Unfortunately, the
+    reviewers did not look at Open Source implementations such as FreeS/WAN
+    or OpenBSD.</li>
+  <li><a
+    href="http://www.tanu.org/~sakane/doc/public/report-ike-interop0007.html">results</a>
+    from interoperability tests at a conference. FreeS/WAN was not tested
+    there.</li>
+  <li>test results from the <a
+    href="http://www.hsc.fr/ressources/veille/ipsec/ipsec2000/">IPSEC
+    2000</a> conference</li>
+</ul>
+
+<h4><a name="test1">Interoperability test sites</a></h4>
+<ul>
+  <li><a href="http://www.tahi.org/">TAHI</a>, a Japanese IPv6 testing
+    project with free IPsec validation software</li>
+  <li><a href="http://ipsec-wit.antd.nist.gov">National Institute of
+    Standards and Technology</a></li>
+  <li><a href="http://isakmp-test.ssh.fi/">SSH Communications
+  Security</a></li>
+</ul>
+
+<h2><a name="linux.link">Linux links</a></h2>
+
+<h3><a name="linux.basic">Basic and tutorial Linux information</a></h3>
+<ul>
+  <li>Linux <a
+    href="http://linuxcentral.com/linux/LDP/LDP/gs/gs.html">Getting
+    Started</a> HOWTO document</li>
+  <li>A getting started guide from the <a
+    href="http://darkwing.uoregon.edu/~cchome/linuxgettingstarted.html">U of
+    Oregon</a></li>
+  <li>A large <a href="http://www.herring.org/techie.html">link
+    collection</a> which includes a lot of introductory and tutorial material
+    on Unix, Linux, the net, . . .</li>
+</ul>
+
+<h3><a name="general">General Linux sites</a></h3>
+<ul>
+  <li><a href="http://www.freshmeat.net">Freshmeat</a> Linux news</li>
+  <li><a href="http://slashdot.org">Slashdot</a> "News for Nerds"</li>
+  <li><a href="http://www.linux.org">Linux Online</a></li>
+  <li><a href="http://www.linuxhq.com">Linux HQ</a></li>
+  <li><a href="http://www.tux.org">tux.org</a></li>
+</ul>
+
+<h3><a name="docs.ldp">Documentation</a></h3>
+
+<p>Nearly any Linux documentation you are likely to want can be found at the
+<a href="http://metalab.unc.edu/LDP">Linux Documentation Project</a> or
+LDP.</p>
+<ul>
+  <li><a href="http://metalab.unc.edu/LDP/HOWTO/META-FAQ.html">Meta-FAQ</a>
+    guide to Linux information sources</li>
+  <li>The LDP's HowTo documents are a standard Linux reference. See this <a
+    href="http://www.linuxdoc.org/docs.html#howto">list</a>. Documents there
+    most relevant to a FreeS/WAN gateway are:
+    <ul>
+      <li><a href="http://metalab.unc.edu/LDP/HOWTO/Kernel-HOWTO.html">Kernel
+        HOWTO</a></li>
+      <li><a
+        href="http://metalab.unc.edu/LDP/HOWTO/Networking-Overview-HOWTO.html">Networking
+        Overview HOWTO</a></li>
+      <li><a
+        href="http://metalab.unc.edu/LDP/HOWTO/Security-HOWTO.html">Security
+        HOWTO</a></li>
+    </ul>
+  </li>
+  <li>The LDP do a series of Guides, book-sized publications with more detail
+    (and often more "why do it this way?") than the HowTos. See this <a
+    href="http://www.linuxdoc.org/guides.html">list</a>. Documents there most
+    relevant to a FreeS/WAN gateway are:
+    <ul>
+      <li><a href="http://www.tml.hut.fi/~viu/linux/sag/">System
+        Administrator's Guide</a></li>
+      <li><a href="http://www.linuxdoc.org/LDP/nag2/index.html">Network
+        Adminstrator's Guide</a></li>
+      <li><a href="http://www.seifried.org/lasg/">Linux Administrator's
+        Security Guide</a></li>
+    </ul>
+  </li>
+</ul>
+
+<p>You may not need to go to the LDP to get this material. Most Linux
+distributions include the HowTos on their CDs and several include the Guides
+as well. Also, most of the Guides and some collections of HowTos are
+available in book form from various publishers.</p>
+
+<p>Much of the LDP material is also available in languages other than
+English. See this <a href="http://www.linuxdoc.org/links/nenglish.html">LDP
+page</a>.</p>
+
+<h3><a name="advroute.web">Advanced routing</a></h3>
+
+<p>The Linux IP stack has some new features in 2.4 kernels. Some HowTos have
+been written:</p>
+<ul>
+  <li>several HowTos for the <a
+    href="http://netfilter.samba.org/unreliable-guides/">netfilter</a>
+    firewall code in newer kernels</li>
+  <li><a
+    href="http://www.ds9a.nl/2.4Networking/HOWTO//cvs/2.4routing/output/2.4networking.html">2.4
+    networking</a> HowTo</li>
+  <li><a
+    href="http://www.ds9a.nl/2.4Networking/HOWTO//cvs/2.4routing/output/2.4routing.html">2.4
+    routing</a> HowTo</li>
+</ul>
+
+<h3><a name="linsec">Security for Linux</a></h3>
+
+<p>See also the <a href="#docs.ldp">LDP material</a> above.</p>
+<ul>
+  <li><a
+    href="http://www.ecst.csuchico.edu/~dranch/LINUX/index-linux.html#trinityos">Trinity
+    OS guide to setting up Linux</a></li>
+  <li><a href="http://www.deter.com/unix">Unix security</a> page</li>
+  <li><a href="http://linux01.gwdg.de/~alatham/">PPDD</a> encrypting
+    filesystem</li>
+  <li><a href="http://EncryptionHOWTO.sourceforge.net/">Linux Encryption
+    HowTo</a> (outdated when last checked, had an Oct 2000 revision date in
+    March 2002)</li>
+</ul>
+
+<h3><a name="firewall.linux">Linux firewalls</a></h3>
+
+<p>Our <a href="firewall.html">FreeS/WAN and firewalls</a> document includes
+links to several sets of <a href="firewall.html#examplefw">scripts</a> known
+to work with FreeS/WAN.</p>
+
+<p>Other information sources:</p>
+<ul>
+  <li><a href="http://ipmasq.cjb.net/">IP Masquerade resource page</a></li>
+  <li><a href="http://netfilter.samba.org/unreliable-guides/">netfilter</a>
+    firewall code in 2.4 kernels</li>
+  <li>Our list of general <a href="#firewall.web">firewall references</a> on
+    the web</li>
+  <li><a href="http://users.dhp.com/~whisper/mason/">Mason</a>, a tool for
+    automatically configuring Linux firewalls</li>
+  <li>the web cache software <a href="http://www.squid-cache.org/">squid</a>
+    and <a href="http://www.squidguard.org/">squidguard</a> which turns Squid
+    into a filtering web proxy</li>
+</ul>
+
+<h3><a name="linux.misc">Miscellaneous Linux information</a></h3>
+<ul>
+  <li><a href="http://lwn.net/current/dists.php3">Linux distribution
+    vendors</a></li>
+  <li><a href="http://www.linux.org/groups/">Linux User Groups</a></li>
+</ul>
+
+<h2><a name="crypto.link">Crypto and security links</a></h2>
+
+<h3><a name="security">Crypto and security resources</a></h3>
+
+<h4><a name="std.links">The standard link collections</a></h4>
+
+<p>Two enormous collections of links, each the standard reference in its
+area:</p>
+<dl>
+  <dt>Gene Spafford's <a
+  href="http://www.cerias.purdue.edu/coast/hotlist/">COAST hotlist</a></dt>
+    <dd>Computer and network security.</dd>
+  <dt>Peter Gutmann's <a
+  href="http://www.cs.auckland.ac.nz/~pgut001/links.html">Encryption and
+  Security-related Resources</a></dt>
+    <dd>Cryptography.</dd>
+</dl>
+
+<h4><a name="FAQ">Frequently Asked Question (FAQ) documents</a></h4>
+<ul>
+  <li><a href="http://www.faqs.org/faqs/cryptography-faq/">Cryptography
+    FAQ</a></li>
+  <li><a href="http://www.interhack.net/pubs/fwfaq">Firewall FAQ</a></li>
+  <li><a href="http://www.whitefang.com/sup/secure-faq.html">Secure Unix
+    Programming FAQ</a></li>
+  <li>FAQs for specific programs are listed in the <a href="#tools">tools</a>
+    section below.</li>
+</ul>
+
+<h4><a name="cryptover">Tutorials</a></h4>
+<ul>
+  <li>Gary Kessler's <a
+    href="http://www.garykessler.net/library/crypto.html">Overview of
+    Cryptography</a></li>
+  <li>Terry Ritter's <a
+    href="http://www.ciphersbyritter.com/LEARNING.HTM">introduction</a></li>
+  <li>Peter Gutman's <a
+    href="http://www.cs.auckland.ac.nz/~pgut001/tutorial/index.html">cryptography</a>
+    tutorial (500 slides in PDF format)</li>
+  <li>Amir Herzberg of IBM's sildes for his course <a
+    href="http://www.hrl.il.ibm.com/mpay/course.html">Introduction to
+    Cryptography and Electronic Commerce</a></li>
+  <li>the <a href="http://www.gnupg.org/gph/en/manual/c173.html">concepts
+    section</a> of the <a href="glossary.html#GPG">GNU Privacy Guard</a>
+    documentation</li>
+  <li>Bruce Schneier's self-study <a
+    href="http://www.counterpane.com/self-study.html">cryptanalysis</a>
+  course</li>
+</ul>
+
+<p>See also the <a href="#interesting">interesting papers</a> section
+below.</p>
+
+<h4><a name="standards">Crypto and security standards</a></h4>
+<ul>
+  <li><a href="http://csrc.nist.gov/cc">Common Criteria</a>, new
+    international computer and network security standards to replace the
+    "Rainbow" series</li>
+  <li>AES <a href="http://csrc.nist.gov/encryption/aes/aes_home.htm">
+    Advanced Encryption Standard </a> which will replace DES</li>
+  <li><a href="http://grouper.ieee.org/groups/1363">IEEE P-1363 public key
+    standard</a></li>
+  <li>our collection of links for the <a href="#ipsec.link">IPsec</a>
+    standards</li>
+  <li>history of <a
+    href="http://www.visi.com/crypto/evalhist/index.html">formal
+    evaluation</a> of security policies and implementation</li>
+</ul>
+
+<h4><a name="quotes">Crypto quotes</a></h4>
+
+<p>There are several collections of cryptographic quotes on the net:</p>
+<ul>
+  <li><a href="http://www.eff.org/pub/EFF/quotes.eff">the EFF</a></li>
+  <li><a href="http://www.samsimpson.com/cquotes.php">Sam Simpson</a></li>
+  <li><a href="http://www.amk.ca/quotations/cryptography/page-1.html">AM
+    Kutchling</a></li>
+</ul>
+
+<h3><a name="policy">Cryptography law and policy</a></h3>
+
+<h4><a name="legal">Surveys of crypto law</a></h4>
+<ul>
+  <li>International survey of <a
+    href="http://cwis.kub.nl/~FRW/PEOPLE/koops/lawsurvy.htm"> crypto
+  law</a>.</li>
+  <li>International survey of <a
+    href="http://rechten.kub.nl/simone/ds-lawsu.htm"> digital signature
+    law</a></li>
+</ul>
+
+<h4><a name="oppose">Organisations opposing crypto restrictions</a></h4>
+<ul>
+  <li>The <a href="glossary.html#EFF">EFF</a>'s archives on <a
+    href="http://www.eff.org/pub/Privacy/">privacy</a> and <a
+    href="http://www.eff.org/pub/Privacy/ITAR_export/">export
+  control</a>.</li>
+  <li><a href="http://www.gilc.org">Global Internet Liberty Campaign</a></li>
+  <li><a href="http://www.cdt.org/crypto">Center for Democracy and
+    Technology</a></li>
+  <li><a href="http://www.privacyinternational.org/">Privacy
+    International</a>, who give out <a
+    href="http://www.bigbrotherawards.org/">Big Brother Awards</a> to snoopy
+    organisations</li>
+</ul>
+
+<h4><a name="other.policy">Other information on crypto policy</a></h4>
+<ul>
+  <li><a href="ftp://ftp.isi.edu/in-notes/rfc1984.txt">RFC 1984</a>, the <a
+    href="glossary.html#IAB">IAB</a> and <a
+    href="glossary.html#IESG">IESG</a> Statement on Cryptographic Technology
+    and the Internet.</li>
+  <li>John Young's collection of <a href="http://cryptome.org/">documents</a>
+    of interest to the cryptography, open government and privacy movements,
+    organized chronologically</li>
+  <li>AT&amp;T researcher Matt Blaze's Encryption, Privacy and Security <a
+    href="http://www.crypto.com">Resource Page</a></li>
+  <li>A good <a href="http://cryptome.org/crypto97-ne.htm">overview</a> of
+    the issues from Australia.</li>
+</ul>
+
+<p>See also our documentation section on the <a href="politics.html">history
+and politics</a> of cryptography.</p>
+
+<h3><a name="crypto.tech">Cryptography technical information</a></h3>
+
+<h4><a name="cryptolinks">Collections of crypto links</a></h4>
+<ul>
+  <li><a href="http://www.counterpane.com/hotlist.html">Counterpane</a></li>
+  <li><a href="http://www.cs.auckland.ac.nz/~pgut001/links.html">Peter
+    Gutman's links</a></li>
+  <li><a href="http://www.pca.dfn.de/eng/team/ske/pem-dok.html">PKI
+  links</a></li>
+  <li><a href="http://crypto.yashy.com/www/">Robert Guerra's links</a></li>
+</ul>
+
+<h4><a name="papers">Lists of online cryptography papers</a></h4>
+<ul>
+  <li><a href="http://www.counterpane.com/biblio">Counterpane</a></li>
+  <li><a
+    href="http://www.cryptography.com/resources/papers">cryptography.com</a></li>
+  <li><a href="http://www.cryptosoft.com/html/secpub.htm">Cryptosoft</a></li>
+</ul>
+
+<h4><a name="interesting">Particularly interesting papers</a></h4>
+
+<p>These papers emphasize important issues around the use of cryptography,
+and the design and management of secure systems.</p>
+<ul>
+  <li><a href="http://www.counterpane.com/keylength.html">Key length
+    requirements for security</a></li>
+  <li><a href="http://www.cl.cam.ac.uk/users/rja14/wcf.html">Why
+    Cryptosystems Fail</a></li>
+  <li><a href="http://www.cdt.org/crypto/risks98/">Risks of escrowed
+    encryption</a></li>
+  <li><a href="http://www.counterpane.com/pitfalls.html">Security pitfalls in
+    cryptography</a></li>
+  <li><a href="http://www.acm.org/classics/sep95">Reflections on Trusting
+    Trust</a>, Ken Thompson on Trojan horse design</li>
+  <li><a href="http://www.apache-ssl.org/disclosure.pdf">Security against
+    Compelled Disclosure</a>, how to maintain privacy in the face of legal or
+    other coersion</li>
+</ul>
+
+<h3><a name="compsec">Computer and network security</a></h3>
+
+<h4><a name="seclink">Security links</a></h4>
+<ul>
+  <li><a href="http://www.cs.purdue.edu/coast/hotlist">COAST Hotlist</a></li>
+  <li>DMOZ open directory project <a
+    href="http://dmoz.org/Computers/Security/">computer security</a>
+  links</li>
+  <li><a href="http://www-cse.ucsd.edu/users/bsy/sec.html">Bennet Yee</a></li>
+  <li>Mike Fuhr's <a
+    href="http://www.fuhr.org/~mfuhr/computers/security.html">link
+    collection</a></li>
+  <li><a href="http://www.networkintrusion.co.uk/">links</a> with an emphasis
+    on intrusion detection</li>
+</ul>
+
+<h4><a name="firewall.web">Firewall links</a></h4>
+<ul>
+  <li><a href="http://www.cs.purdue.edu/coast/firewalls">COAST
+  firewalls</a></li>
+  <li><a href="http://www.zeuros.co.uk">Firewalls Resource page</a></li>
+</ul>
+
+<h4><a name="vpn">VPN links</a></h4>
+<ul>
+  <li><a href="http://www.vpnc.org">VPN Consortium</a></li>
+  <li>First VPN's <a href="http://www.firstvpn.com/research/rhome.html">white
+    paper</a> collection</li>
+</ul>
+
+<h4><a name="tools">Security tools</a></h4>
+<ul>
+  <li>PGP -- mail encryption
+    <ul>
+      <li><a href="http://www.pgp.com/">PGP Inc.</a> (part of NAI) for
+        commercial versions</li>
+      <li><a href="http://web.mit.edu/network/pgp.html">MIT</a> distributes
+        the NAI product for non-commercial use</li>
+      <li><a href="http://www.pgpi.org/">international</a> distribution
+      site</li>
+      <li><a href="http://gnupg.org">GNU Privacy Guard (GPG)</a></li>
+      <li><a href="http://www.dk.pgp.net/pgpnet/pgp-faq/">PGP FAQ</a></li>
+    </ul>
+    A message in our mailing list archive has considerable detail on <a
+    href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/12/msg00029.html">available
+    versions</a> of PGP and on IPsec support in them.
+    <p><strong>Note:</strong> A fairly nasty bug exists in all commercial PGP
+    versions from 5.5 through 6.5.3. If you have one of those,
+    <strong>upgrade now</strong>.</p>
+  </li>
+  <li>SSH -- secure remote login
+    <ul>
+      <li><a href="http://www.ssh.fi">SSH Communications Security</a>, for
+        the original software. It is free for trial, academic and
+        non-commercial use.</li>
+      <li><a href="http://www.openssh.com/">Open SSH</a>, the Open BSD team's
+        free replacement</li>
+      <li><a href="http://www.freessh.org/">freessh.org</a>, links to free
+        implementations for many systems</li>
+      <li><a href="http://www.uni-karlsruhe.de/~ig25/ssh-faq">SSH FAQ</a></li>
+      <li><a
+        href="http://www.chiark.greenend.org.uk/~sgtatham/putty/">Putty</a>,
+        an SSH client for Windows</li>
+    </ul>
+  </li>
+  <li>Tripwire saves message digests of your system files. Re-calculate the
+    digests and compare to saved values to detect any file changes. There are
+    several versions available:
+    <ul>
+      <li><a href="http://www.tripwiresecurity.com/">commercial
+      version</a></li>
+      <li><a href="http://www.tripwire.org/">Open Source</a></li>
+    </ul>
+  </li>
+  <li><a href="http://www.snort.org">Snort</a> and <a
+    href="http://www.lids.org">LIDS</a> are intrusion detection system for
+    Linux</li>
+  <li><a href="http://www.fish.com/~zen/satan/satan.html">SATAN</a> System
+    Administrators Tool for Analysing Networks</li>
+  <li><a href="http://www.insecure.org/nmap/">NMAP</a> Network Mapper</li>
+  <li><a href="ftp://ftp.porcupine.org/pub/security/index.html">Wietse
+    Venema's page</a> with various tools</li>
+  <li><a href="http://ita.ee.lbl.gov/index.html">Internet Traffic
+    Archive</a>, various tools to analyze network traffic, mostly scripts to
+    organise and format tcpdump(8) output for specific purposes</li>
+  <li><a name="ssmail">ssmail -- sendmail patched to do</a> <a
+    href="glossary.html#carpediem">opportunistic encryption</a>
+    <ul>
+      <li><a href="http://www.home.aone.net.au/qualcomm/">web page</a> with
+        links to code and to a Usenix paper describing it, in PDF</li>
+    </ul>
+  </li>
+  <li><a href="http://www.openca.org/">Open CA</a> project to develop a
+    freely distributed <a href="glossary.html#CA">Certification Authority</a>
+    for building a open <a href="glossary.html#PKI">Public Key
+    Infrastructure</a>.</li>
+</ul>
+
+<h3><a name="people">Links to home pages</a></h3>
+
+<p>David Wagner at Berkeley provides a set of links to <a
+href="http://www.cs.berkeley.edu/~daw/people/crypto.html">home pages</a> of
+cryptographers, cypherpunks and computer security people.</p>
+</body>
+</html>
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
+H5 { font-family: sans-serif }
+H6 { font-family: sans-serif }
+SUB { font-size: smaller }
+SUP { font-size: smaller }
+PRE { font-family: monospace }
+--></STYLE>
+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="performance.html">Previous</A>
+<A HREF="kernel.html">Next</A>
+<HR>
+<H1><A name="test.freeswan">Testing FreeS/WAN</A></H1>
+ This document discusses testing FreeS/WAN.
+<P>Not all types of testing are described here. Other parts of the
+ documentation describe some tests:</P>
+<DL>
+<DT><A href="install.html#testinstall">installation</A> document</DT>
+<DD>testing for a successful install</DD>
+<DT><A href="config.html#testsetup">configuration</A> document</DT>
+<DD>basic tests for a working configuration</DD>
+<DT><A href="web.html#interop.web">web links</A> document</DT>
+<DD>General information on tests for interoperability between various
+ IPsec implementations. This includes links to several test sites.</DD>
+<DT><A href="interop.html">interoperation</A> document.</DT>
+<DD>More specific information on FreeS/WAN interoperation with other
+ implementations.</DD>
+<DT><A href="performance.html">performance</A> document</DT>
+<DD>performance measurements</DD>
+</DL>
+<P>The test setups and procedures described here can also be used in
+ other testing, but this document focuses on testing the IPsec
+ functionality of FreeS/WAN.</P>
+<H2><A NAME="test.oe">Testing opportunistic connections</A></H2>
+<P>This section teaches you how to test your opportunistically encrypted
+ (OE) connections. To set up OE, please see the easy instructions in our<A
+HREF="quickstart.html"> quickstart guide</A>.</P>
+<H3><A NAME="12_1_1">Basic OE Test</A></H3>
+<P>This test is for basic OE functionality.
+<!-- You may use it on an 
+<A HREF="quickstart.html#oppo.client">initiate-only OE</A> box or a 
+<A HREF="quickstart.html#opp.incoming">full OE</A> box. -->
+ For additional tests, keep
+ reading.</P>
+<P>Be sure IPsec is running. You can see whether it is with:</P>
+<PRE>    ipsec setup status</PRE>
+<P>If need be, you can restart it with:</P>
+<PRE>    service ipsec restart</PRE>
+<P>Load a FreeS/WAN test website from the host on which you're running
+ FreeS/WAN. Note: the feds may be watching these sites. Type one of:</P>
+<P></P>
+<PRE>   links oetest.freeswan.org</PRE>
+<PRE>   links oetest.freeswan.nl</PRE>
+
+<!--<PRE>   links oetest.freeswan.ca</PRE>-->
+<P>A positive result looks like this:</P>
+<PRE>
+   You  seem  to  be  connecting  from:  192.0.2.11 which DNS says is:
+   gateway.example.com
+     _________________________________________________________________
+                                                                                
+   Status E-route
+   OE    enabled    16    192.139.46.73/32    -&gt;    192.0.2.11/32   =&gt;
+   tun0x2097@192.0.2.11
+   OE    enabled    176    192.139.46.77/32    -&gt;   192.0.2.11/32   =&gt;
+   tun0x208a@192.0.2.11
+</PRE>
+<P>If you see this, congratulations! Your OE box will now encrypt its
+ own traffic whenever it can. If you have difficulty, see our<A HREF="quickstart.html#oe.trouble">
+ OE troubleshooting tips</A>.</P>
+<H3><A NAME="12_1_2">OE Gateway Test</A></H3>
+<P>If you've set up FreeS/WAN to protect a subnet behind your gateway,
+ you'll need to run another simple test, which can be done from a
+ machine running any OS. That's right, your Windows box can be protected
+ by opportunistic encryption without any FreeS/WAN install or
+ configuration on that box. From<STRONG> each protected subnet node</STRONG>
+, load the FreeS/WAN website with:</P>
+<PRE>   links oetest.freeswan.org</PRE>
+<PRE>   links oetest.freeswan.nl</PRE>
+<P>A positive result looks like this:</P>
+<PRE>
+   You  seem  to  be  connecting  from:  192.0.2.98 which DNS says is:
+   box98.example.com
+     _________________________________________________________________
+                                                                                
+   Status E-route
+   OE    enabled    16    192.139.46.73/32    -&gt;    192.0.2.98/32   =&gt;
+   tun0x134ed@192.0.2.11
+   OE    enabled    176    192.139.46.77/32    -&gt;   192.0.2.11/32   =&gt;
+   tun0x134d2@192.0.2.11
+</PRE>
+<P>If you see this, congratulations! Your OE gateway will now encrypt
+ traffic for this subnet node whenever it can. If you have difficulty,
+ see our<A HREF="quickstart.html#oe.trouble"> OE troubleshooting tips</A>
+.</P>
+<H3><A NAME="12_1_3">Additional OE tests</A></H3>
+<P>When testing OE, you will often find it useful to execute this
+ command on the FreeS/WAN host:</P>
+<PRE>   ipsec eroute</PRE>
+<P>If you have established a connection (either for or for a subnet
+ node) you will see a result like:</P>
+<PRE>    192.0.2.11/32   -&gt; 192.139.46.73/32  =&gt; tun0x149f@192.139.46.38
+</PRE>
+<P>Key:</P>
+<TABLE>
+<TR><TD>1.</TD><TD>192.0.2.11/32</TD><TD>Local start point of the
+ protected traffic.</TD></TR>
+<TR><TD>2.</TD><TD>192.0.2.194/32</TD><TD>Remote end point of the
+ protected traffic.</TD></TR>
+<TR><TD>3.</TD><TD>192.0.48.38</TD><TD>Remote FreeS/WAN node (gateway or
+ host). May be the same as (2).</TD></TR>
+<TR><TD>4.</TD><TD>[not shown]</TD><TD>Local FreeS/WAN node (gateway or
+ host), where you've produced the output. May be the same as (1).</TD></TR>
+</TABLE>
+<P>For extra assurance, you may wish to use a packet sniffer such as<A HREF="http://www.tcpdump.org">
+ tcpdump</A> to verify that packets are being encrypted. You should see
+ output that indicates<STRONG> ESP</STRONG> encrypted data, for example:</P>
+<PRE>    02:17:47.353750 PPPoE  [ses 0x1e12] IP 154: xy.example.com &gt; oetest.freeswan.org: ESP(spi=0x87150d16,seq=0x55)</PRE>
+<H2><A name="test.uml">Testing with User Mode Linux</A></H2>
+<P><A href="http://user-mode-linux.sourceforge.net/">User Mode Linux</A>
+ allows you to run Linux as a user process on another Linux machine.</P>
+<P>As of 1.92, the distribution has a new directory named testing. It
+ contains a collection of test scripts and sample configurations. Using
+ these, you can bring up several copies of Linux in user mode and have
+ them build tunnels to each other. This lets you do some testing of a
+ FreeS/WAN configuration on a single machine.</P>
+<P>You need a moderately well-endowed machine for this to work well.
+ Each UML wants about 16 megs of memory by default, which is plenty for
+ FreeS/WAN usage. Typical regression testing only occasionally uses as
+ many as 4 UMLs. If one is doing nothing else with the machine (in
+ particular, not running X on it), then 128 megs and a 500MHz CPU are
+ fine.</P>
+ Documentation on these scripts is<A href="umltesting.html"> here</A>.
+ There is also documentation on automated testing<A href="makecheck.html">
+ here</A>.
+<H2><A name="testnet">Configuration for a testbed network</A></H2>
+<P>A common test setup is to put a machine with dual Ethernet cards in
+ between two gateways under test. You need at least five machines; two
+ gateways, two clients and a testing machine in the middle.</P>
+<P>The central machine both routes packets and provides a place to run
+ diagnostic software for checking IPsec packets. See next section for
+ discussion of<A href="faq.html#tcpdump.faq"> using tcpdump(8)</A> for
+ this.</P>
+<P>This makes things more complicated than if you just connected the two
+ gateway machines directly to each other, but it also makes your test
+ setup much more like the environment you actually use IPsec in. Those
+ environments nearly always involve routing, and quite a few apparent
+ IPsec failures turn out to be problems with routing or with firewalls
+ dropping packets. This approach lets you deal with those problems on
+ your test setup.</P>
+<P>What you end up with looks like:</P>
+<H3><A name="testbed">Testbed network</A></H3>
+<PRE>      subnet a.b.c.0/24
+             |
+      eth1 = a.b.c.1
+         gate1
+      eth0 = 192.168.p.1
+             |
+             |
+      eth0 = 192.168.p.2
+         route/monitor box
+      eth1 = 192.168.q.2
+             |
+             |
+      eth0 = 192.168.q.1
+         gate2
+      eth1 = x.y.z.1
+              |
+       subnet x.y.z.0/24</PRE>
+<PRE>Where p and q are any convenient values that do not interfere with other
+routes you may have. The ipsec.conf(5) file then has, among other things:</PRE>
+<PRE>conn abc-xyz
+      left=192.168.p.1
+      leftnexthop=192.168.p.2
+      right=192.168.q.1
+      rightnexthop=192.168.q.2</PRE>
+<P>Once that works, you can remove the &quot;route/monitor box&quot;, and connect
+ the two gateways to the Internet. The only parameters in ipsec.conf(5)
+ that need to change are the four shown above. You replace them with
+ values appropriate for your Internet connection, and change the eth0 IP
+ addresses and the default routes on both gateways.</P>
+<P>Note that nothing on either subnet needs to change. This lets you
+ test most of your IPsec setup before connecting to the insecure
+ Internet.</P>
+<H3><A name="tcpdump.test">Using packet sniffers in testing</A></H3>
+<P>A number of tools are available for looking at packets. We will
+ discuss using<A href="http://www.tcpdump.org/"> tcpdump(8)</A>, a
+ common Linux tool included in most distributions. Alternatives
+ offerring more-or-less the same functionality include:</P>
+<DL>
+<DT><A href="http://www.ethereal.com">Ethereal</A></DT>
+<DD>Several people on our mailing list report a preference for this over
+ tcpdump.</DD>
+<DT><A href="http://netgroup-serv.polito.it/windump/">windump</A></DT>
+<DD>a Windows version of tcpdump(8), possibly handy if you have Windows
+ boxes in your network</DD>
+<DT><A href="http://reptile.rug.ac.be/~coder/sniffit/sniffit.html">
+Sniffit</A></DT>
+<DD>A linux sniffer that we don't know much about. If you use it, please
+ comment on our mailing list.</DD>
+</DL>
+<P>See also this<A href="http://www.tlsecurity.net/unix/ids/sniffer/">
+ index</A> of packet sniffers.</P>
+<P>tcpdump(8) may misbehave if run on the gateways themselves. It is
+ designed to look into a normal IP stack and may become confused if you
+ ask it to display data from a stack which has IPsec in play.</P>
+<P>At one point, the problem was quite severe. Recent versions of
+ tcpdump, however, understand IPsec well enough to be usable on a
+ gateway. You can get the latest version from<A href="http://www.tcpdump.org/">
+ tcpdump.org</A>.</P>
+<P>Even with a recent tcpdump, some care is required. Here is part of a
+ post from Henry on the topic:</P>
+<PRE>&gt; a) data from sunset to sunrise or the other way is not being
+&gt; encrypted (I am using tcpdump (ver. 3.4) -x/ping -p to check
+&gt; packages) 
+
+What *interface* is tcpdump being applied to?  Use the -i option to
+control this.  It matters!  If tcpdump is looking at the ipsecN
+interfaces, e.g. ipsec0, then it is seeing the packets before they are
+encrypted or after they are decrypted, so of course they don't look
+encrypted.  You want to have tcpdump looking at the actual hardware
+interfaces, e.g. eth0. 
+
+Actually, the only way to be *sure* what you are sending on the wire is to
+have a separate machine eavesdropping on the traffic.  Nothing you can do
+on the machines actually running IPsec is 100% guaranteed reliable in this
+area (although tcpdump is a lot better now than it used to be).</PRE>
+<P>The most certain way to examine IPsec packets is to look at them on
+ the wire. For security, you need to be certain, so we recommend doing
+ that. To do so, you need a<STRONG> separate sniffer machine located
+ between the two gateways</STRONG>. This machine can be routing IPsec
+ packets, but it must not be an IPsec gateway. Network configuration for
+ such testing is discussed<A href="#testnet"> above</A>.</P>
+<P>Here's another mailing list message with advice on using tcpdump(8):</P>
+<PRE>Subject: RE: [Users] Encrypted???
+   Date: Thu, 29 Nov 2001
+   From: &quot;Joe Patterson&quot; &lt;jpatterson@asgardgroup.com&gt;
+
+tcpdump -nl -i $EXT-IF proto 50
+
+-nl tells it not to buffer output or resolve names (if you don't do that it
+may confuse you by not outputing anything for a while), -i $EXT-IF (replace
+with your external interface) tells it what interface to listen on, and
+proto 50 is ESP.  Use &quot;proto 51&quot; if for some odd reason you're using AH, and
+&quot;udp port 500&quot; if you want to see the isakmp key exchange/tunnel setup
+packets.
+
+You can also run `tcpdump -nl -i ipsec0` to see what traffic is on that
+virtual interface.  Anything you see there *should* be either encrypted or
+dropped (unless you've turned on some strange options in your ipsec.conf
+file)
+
+Another very handy thing is ethereal (http://www.ethereal.com/) which runs
+on just about anything, has a nice gui interface (or a nice text-based
+interface), and does a great job of protocol  breakdown.  For ESP and AH
+it'll basically just tell you that there's a packet of that protocol, and
+what the spi is, but for isakmp it'll actually show you a lot of the tunnel
+setup information (until it gets to the point in the protocol where isakmp
+is encrypted....)</PRE>
+<H2><A name="verify.crypt">Verifying encryption</A></H2>
+<P>The question of how to verify that messages are actually encrypted
+ has been extensively discussed on the mailing list. See this<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/07/msg00262.html">
+ thread</A>.</P>
+<P>If you just want to verify that packets are encrypted, look at them
+ with a packet sniffer (see<A href="#tcpdump.test"> previous section</A>
+) located between the gateways. The packets should, except for some of
+ the header information, be utterly unintelligible.<STRONG> The output
+ of good encryption looks<EM> exactly</EM> like random noise</STRONG>.</P>
+<P>A packet sniffer can only tell you that the data you looked at was
+ encrypted. If you have stronger requirements -- for example if your
+ security policy requires verification that plaintext is not leaked
+ during startup or under various anomolous conditions -- then you will
+ need to devise much more thorough tests. If you do that, please post
+ any results or methodological details which your security policy allows
+ you to make public.</P>
+<P>You can put recognizable data into ping packets with something like:</P>
+<PRE>        ping -p feedfacedeadbeef 11.0.1.1</PRE>
+<P>&quot;feedfacedeadbeef&quot; is a legal hexadecimal pattern that is easy to
+ pick out of hex dumps.</P>
+<P>For other protocols, you may need to check if you have encrypted data
+ or ASCII text. Encrypted data has approximately equal frequencies for
+ all 256 possible characters. ASCII text has most characters in the
+ printable range 0x20-0x7f, a few control characters less than 0x20, and
+ none at all in the range 0x80-0xff. 0x20, space, is a good character to
+ look for. In normal English text space occurs about once in seven
+ characters, versus about once in 256 for random or encrypted data.</P>
+<P>One thing to watch for: the output of good compression, like that of
+ good encryption, looks just like random noise. You cannot tell just by
+ looking at a data stream whether it has been compressed, encrypted, or
+ both. You need a little care not to mistake compressed data for
+ encrypted data in your testing.</P>
+<P>Note also that weak encryption also produces random-looking output.
+ You cannot tell whether the encryption is strong by looking at the
+ output. To be sure of that, you would need to have both the algorithms
+ and the implementation examined by experts.</P>
+<P>For IPsec, you can get partial assurance from interoperability tests.
+ See our<A href="interop.html"> interop</A> document. When twenty
+ products all claim to implement<A href="glossary.html#3DES"> 3DES</A>,
+ and they all talk to each other, you can be fairly sure they have it
+ right. Of course, you might wonder whether all the implementers are
+ consipring to trick you or, more plausibly, whether some
+ implementations might have &quot;back doors&quot; so they can get also it wrong
+ when required.. If you're seriously worried about things like that, you
+ need to get the code you use audited (good luck if it is not Open
+ Source), or perhaps to talk to a psychiatrist about treatments for
+ paranoia.</P>
+<H2><A name="mail.test">Mailing list pointers</A></H2>
+<P>Additional information on testing can be found in these<A href="mail.html">
+ mailing list</A> messages:</P>
+<UL>
+<LI>a user's detailed<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/11/msg00571.html">
+ setup diary</A> for his testbed network</LI>
+<LI>a FreeS/WAN team member's<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/11/msg00425.html">
+ notes</A> from testing at an IPsec interop &quot;bakeoff&quot;</LI>
+</UL>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="performance.html">Previous</A>
+<A HREF="kernel.html">Next</A>
+</BODY>
+</HTML>
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
+H5 { font-family: sans-serif }
+H6 { font-family: sans-serif }
+SUB { font-size: smaller }
+SUP { font-size: smaller }
+PRE { font-family: monospace }
+--></STYLE>
+</HEAD>
+<BODY>
+<H1 ALIGN="CENTER"><A NAME="CONTENTS">Table of Contents</A></H1>
+<BR>
+<BR><B><A HREF="intro.html#intro">Introduction</A></B>
+<UL>
+<LI><A HREF="intro.html#ipsec.intro">IPsec, Security for the Internet
+ Protocol</A></LI>
+<UL>
+<LI><A HREF="intro.html#intro.interop">Interoperating with other IPsec
+ implementations</A></LI>
+<LI><A HREF="ipsec.html#advantages">Advantages of IPsec</A></LI>
+<LI><A HREF="intro.html#applications">Applications of IPsec</A></LI>
+<LI><A HREF="intro.html#types">The need to authenticate gateways</A></LI>
+</UL>
+<LI><A HREF="intro.html#project">The FreeS/WAN project</A></LI>
+<UL>
+<LI><A HREF="intro.html#goals">Project goals</A></LI>
+<LI><A HREF="intro.html#staff">Project team</A></LI>
+</UL>
+<LI><A HREF="intro.html#products">Products containing FreeS/WAN</A></LI>
+<UL>
+<LI><A HREF="intro.html#distwith">Full Linux distributions</A></LI>
+<LI><A HREF="intro.html#kernel_dist">Linux kernel distributions</A></LI>
+<LI><A HREF="intro.html#office_dist">Office server distributions</A></LI>
+<LI><A HREF="intro.html#fw_dist">Firewall distributions</A></LI>
+<LI><A HREF="intro.html#turnkey">Firewall and VPN products</A></LI>
+</UL>
+<LI><A HREF="intro.html#docs">Information sources</A></LI>
+<UL>
+<LI><A HREF="intro.html#docformats">This HowTo, in multiple formats</A></LI>
+<LI><A HREF="intro.html#rtfm">RTFM (please Read The Fine Manuals)</A></LI>
+<LI><A HREF="intro.html#text">Other documents in the distribution</A></LI>
+<LI><A HREF="intro.html#assumptions">Background material</A></LI>
+<LI><A HREF="intro.html#archives">Archives of the project mailing list</A>
+</LI>
+<LI><A HREF="intro.html#howto">User-written HowTo information</A></LI>
+<LI><A HREF="intro.html#applied">Papers on FreeS/WAN</A></LI>
+<LI><A HREF="intro.html#licensing">License and copyright information</A></LI>
+</UL>
+<LI><A HREF="intro.html#sites">Distribution sites</A></LI>
+<UL>
+<LI><A HREF="intro.html#1_5_1">Primary site</A></LI>
+<LI><A HREF="intro.html#mirrors">Mirrors</A></LI>
+<LI><A HREF="intro.html#munitions">The &quot;munitions&quot; archive of Linux
+ crypto software</A></LI>
+</UL>
+<LI><A HREF="intro.html#1_6">Links to other sections</A></LI>
+</UL>
+<B><A HREF="upgrading.html#2">Upgrading to FreeS/WAN 2.x</A></B>
+<UL>
+<LI><A HREF="upgrading.html#2_1">New! Built in Opportunistic connections</A>
+</LI>
+<UL>
+<LI><A HREF="upgrading.html#2_1_1">Upgrading Opportunistic Encryption to
+ 2.01 (or later)</A></LI>
+</UL>
+<LI><A HREF="upgrading.html#2_2">New! Policy Groups</A></LI>
+<LI><A HREF="upgrading.html#2_3">New! Packetdefault Connection</A></LI>
+<LI><A HREF="upgrading.html#2_4">FreeS/WAN now disables Reverse Path
+ Filtering</A></LI>
+<LI><A HREF="upgrading.html#2_5">Revised ipsec.conf</A></LI>
+<UL>
+<LI><A HREF="upgrading.html#2_5_1">No promise of compatibility</A></LI>
+<LI><A HREF="upgrading.html#2_5_2">Most ipsec.conf files will work fine</A>
+</LI>
+<LI><A HREF="upgrading.html#2_5_3">Backward compatibility patch</A></LI>
+<LI><A HREF="upgrading.html#2_5_4">Details</A></LI>
+<LI><A HREF="upgrading.html#2_5_5">Upgrading from 1.x RPMs to 2.x RPMs</A>
+</LI>
+</UL>
+</UL>
+<B><A HREF="quickstart.html#quickstart">Quickstart Guide to
+ Opportunistic Encryption</A></B>
+<UL>
+<LI><A HREF="quickstart.html#opp.setup">Purpose</A></LI>
+<UL>
+<LI><A HREF="quickstart.html#3_1_1">OE &quot;flag day&quot;</A></LI>
+</UL>
+<LI><A HREF="quickstart.html#opp.dns">Requirements</A></LI>
+<LI><A HREF="quickstart.html#easy.install">RPM install</A></LI>
+<UL>
+<LI><A HREF="quickstart.html#3_3_1">Download RPMs</A></LI>
+<LI><A HREF="quickstart.html#3_3_2">Check signatures</A></LI>
+<LI><A HREF="quickstart.html#3_3_3">Install the RPMs</A></LI>
+<LI><A HREF="quickstart.html#testinstall">Test</A></LI>
+</UL>
+<LI><A HREF="quickstart.html#opp.setups.list">Our Opportunistic Setups</A>
+</LI>
+<UL>
+<LI><A HREF="quickstart.html#3_4_1">Full or partial opportunism?</A></LI>
+</UL>
+<LI><A HREF="quickstart.html#opp.client">Initiate-only setup</A></LI>
+<UL>
+<LI><A HREF="quickstart.html#3_5_1">Restrictions</A></LI>
+<LI><A HREF="quickstart.html#forward.dns">Create and publish a forward
+ DNS record</A></LI>
+<LI><A HREF="quickstart.html#3_5_3">Test that your key has been
+ published</A></LI>
+<LI><A HREF="quickstart.html#3_5_4">Configure, if necessary</A></LI>
+<LI><A HREF="quickstart.html#3_5_5">Test</A></LI>
+</UL>
+<LI><A HREF="quickstart.html#3_6">Full Opportunism</A></LI>
+<UL>
+<LI><A HREF="quickstart.html#3_6_1">Put a TXT record in a Forward Domain</A>
+</LI>
+<LI><A HREF="quickstart.html#3_6_2">Put a TXT record in Reverse DNS</A></LI>
+<LI><A HREF="quickstart.html#3_6_3">Test your DNS record</A></LI>
+<LI><A HREF="quickstart.html#3_6_4">No Configuration Needed</A></LI>
+<LI><A HREF="quickstart.html#3_6_5">Consider Firewalling</A></LI>
+<LI><A HREF="quickstart.html#3_6_6">Test</A></LI>
+<LI><A HREF="quickstart.html#3_6_7">Test</A></LI>
+</UL>
+<LI><A HREF="quickstart.html#opp.test">Testing opportunistic connections</A>
+</LI>
+<LI><A HREF="quickstart.html#3_8">Now what?</A></LI>
+<LI><A HREF="quickstart.html#3_9">Notes</A></LI>
+<LI><A HREF="quickstart.html#3_10">Troubleshooting OE</A></LI>
+<LI><A HREF="quickstart.html#3_11">Known Issues</A></LI>
+</UL>
+<B><A HREF="policygroups.html#4">How to Configure Linux FreeS/WAN with
+ Policy Groups</A></B>
+<UL>
+<LI><A HREF="policygroups.html#4_1">What are Policy Groups?</A></LI>
+<UL>
+<LI><A HREF="policygroups.html#4_1_1">Built-In Security Options</A></LI>
+</UL>
+<LI><A HREF="policygroups.html#4_2">Using Policy Groups</A></LI>
+<UL>
+<LI><A HREF="policygroups.html#4_2_1">Example 1: Using a Base Policy
+ Group</A></LI>
+<LI><A HREF="policygroups.html#4_2_2">Example 2: Defining IPsec Security
+ Policy with Groups</A></LI>
+<LI><A HREF="policygroups.html#4_2_3">Example 3: Creating a Simple IPsec
+ VPN with the private Group</A></LI>
+<LI><A HREF="policygroups.html#4_2_4">Example 4: New Policy Groups to
+ Protect a Subnet</A></LI>
+<LI><A HREF="policygroups.html#4_2_5">Example 5: Adding a Subnet to the
+ VPN</A></LI>
+</UL>
+<LI><A HREF="policygroups.html#4_3">Appendix</A></LI>
+<UL>
+<LI><A HREF="policygroups.html#4_3_1">Our Hidden Connections</A></LI>
+<LI><A HREF="policygroups.html#4_3_2">Custom Policy Groups</A></LI>
+<LI><A HREF="policygroups.html#4_3_3">Disabling Opportunistic Encryption</A>
+</LI>
+</UL>
+</UL>
+<B><A HREF="faq.html#5">FreeS/WAN FAQ</A></B>
+<UL>
+<LI><A HREF="faq.html#questions">Index of FAQ questions</A></LI>
+<LI><A HREF="faq.html#whatzit">What is FreeS/WAN?</A></LI>
+<LI><A HREF="faq.html#problems">How do I report a problem or seek help?</A>
+</LI>
+<LI><A HREF="faq.html#generic">Can I get ...</A></LI>
+<UL>
+<LI><A HREF="faq.html#lemme_out">Can I get an off-the-shelf system that
+ includes FreeS/WAN?</A></LI>
+<LI><A HREF="faq.html#consultant">Can I hire consultants or staff who
+ know FreeS/WAN?</A></LI>
+<LI><A HREF="faq.html#commercial">Can I get commercial support?</A></LI>
+</UL>
+<LI><A HREF="faq.html#release">Release questions</A></LI>
+<UL>
+<LI><A HREF="faq.html#rel.current">What is the current release?</A></LI>
+<LI><A HREF="faq.html#relwhen">When is the next release?</A></LI>
+<LI><A HREF="faq.html#rel.bugs">Are there known bugs in the current
+ release?</A></LI>
+</UL>
+<LI><A HREF="faq.html#mod_cons">Modifications and contributions</A></LI>
+<UL>
+<LI><A HREF="faq.html#modify.faq">Can I modify FreeS/WAN to ...?</A></LI>
+<LI><A HREF="faq.html#contrib.faq">Can I contribute to the project?</A></LI>
+<LI><A HREF="faq.html#ddoc.faq">Is there detailed design documentation?</A>
+</LI>
+</UL>
+<LI><A HREF="faq.html#interact">Will FreeS/WAN work in my environment?</A>
+</LI>
+<UL>
+<LI><A HREF="faq.html#interop.faq">Can FreeS/WAN talk to ...?</A></LI>
+<LI><A HREF="faq.html#old_to_new">Can different FreeS/WAN versions talk
+ to each other?</A></LI>
+<LI><A HREF="faq.html#faq.bandwidth">Is there a limit on throughput?</A></LI>
+<LI><A HREF="faq.html#faq.number">Is there a limit on number of tunnels?</A>
+</LI>
+<LI><A HREF="faq.html#faq.speed">Is a ... fast enough to handle
+ FreeS/WAN with my loads?</A></LI>
+</UL>
+<LI><A HREF="faq.html#work_on">Will FreeS/WAN work on ... ?</A></LI>
+<UL>
+<LI><A HREF="faq.html#versions">Will FreeS/WAN run on my version of
+ Linux?</A></LI>
+<LI><A HREF="faq.html#nonIntel.faq">Will FreeS/WAN run on non-Intel
+ CPUs?</A></LI>
+<LI><A HREF="faq.html#multi.faq">Will FreeS/WAN run on multiprocessors?</A>
+</LI>
+<LI><A HREF="faq.html#k.old">Will FreeS/WAN work on an older kernel?</A></LI>
+<LI><A HREF="faq.html#k.versions">Will FreeS/WAN run on the latest
+ kernel version?</A></LI>
+<LI><A HREF="faq.html#interface.faq">Will FreeS/WAN work on unusual
+ network hardware?</A></LI>
+<LI><A HREF="faq.html#vlan">Will FreeS/WAN work on a VLAN (802.1q)
+ network?</A></LI>
+</UL>
+<LI><A HREF="faq.html#features.faq">Does FreeS/WAN support ...</A></LI>
+<UL>
+<LI><A HREF="faq.html#VPN.faq">Does FreeS/WAN support site-to-site VPN (
+Virtual Private Network) applications?</A></LI>
+<LI><A HREF="faq.html#warrior.faq">Does FreeS/WAN support remote users
+ connecting to a LAN?</A></LI>
+<LI><A HREF="faq.html#road.shared.possible">Does FreeS/WAN support
+ remote users using shared secret authentication?</A></LI>
+<LI><A HREF="faq.html#wireless.faq">Does FreeS/WAN support wireless
+ networks?</A></LI>
+<LI><A HREF="faq.html#PKIcert">Does FreeS/WAN support X.509 or other PKI
+ certificates?</A></LI>
+<LI><A HREF="faq.html#Radius">Does FreeS/WAN support user authentication
+ (Radius, SecureID, Smart Card...)?</A></LI>
+<LI><A HREF="faq.html#NATtraversal">Does FreeS/WAN support NAT
+ traversal?</A></LI>
+<LI><A HREF="faq.html#virtID">Does FreeS/WAN support assigning a
+ &quot;virtual identity&quot; to a remote system?</A></LI>
+<LI><A HREF="faq.html#noDES.faq">Does FreeS/WAN support single DES
+ encryption?</A></LI>
+<LI><A HREF="faq.html#AES.faq">Does FreeS/WAN support AES encryption?</A>
+</LI>
+<LI><A HREF="faq.html#other.cipher">Does FreeS/WAN support other
+ encryption algorithms?</A></LI>
+</UL>
+<LI><A HREF="faq.html#canI">Can I ...</A></LI>
+<UL>
+<LI><A HREF="faq.html#policy.preconfig">Can I use policy groups along
+ with explicitly configured connections?</A></LI>
+<LI><A HREF="faq.html#policy.off">Can I turn off policy groups?</A></LI>
+<LI><A HREF="faq.html#reload">Can I reload connection info without
+ restarting?</A></LI>
+<LI><A HREF="faq.html#masq.faq">Can I use several masqueraded subnets?</A>
+</LI>
+<LI><A HREF="faq.html#dup_route">Can I use subnets masqueraded to the
+ same addresses?</A></LI>
+<LI><A HREF="faq.html#road.masq">Can I assign a road warrior an address
+ on my net (a virtual identity)?</A></LI>
+<LI><A HREF="faq.html#road.many">Can I support many road warriors with
+ one gateway?</A></LI>
+<LI><A HREF="faq.html#road.PSK">Can I have many road warriors using
+ shared secret authentication?</A></LI>
+<LI><A HREF="faq.html#QoS">Can I use Quality of Service routing with
+ FreeS/WAN?</A></LI>
+<LI><A HREF="faq.html#deadtunnel">Can I recognise dead tunnels and shut
+ them down?</A></LI>
+<LI><A HREF="faq.html#demanddial">Can I build IPsec tunnels over a
+ demand-dialed link?</A></LI>
+<LI><A HREF="faq.html#GRE">Can I build GRE, L2TP or PPTP tunnels over
+ IPsec?</A></LI>
+<LI><A HREF="faq.html#NetBIOS">... use Network Neighborhood (Samba,
+ NetBIOS) over IPsec?</A></LI>
+</UL>
+<LI><A HREF="faq.html#setup.faq">Life's little mysteries</A></LI>
+<UL>
+<LI><A HREF="faq.html#cantping">I cannot ping ....</A></LI>
+<LI><A HREF="faq.html#forever">It takes forever to ...</A></LI>
+<LI><A HREF="faq.html#route">I send packets to the tunnel with route(8)
+ but they vanish</A></LI>
+<LI><A HREF="faq.html#down_route">When a tunnel goes down, packets
+ vanish</A></LI>
+<LI><A HREF="faq.html#firewall_ate">The firewall ate my packets!</A></LI>
+<LI><A HREF="faq.html#dropconn">Dropped connections</A></LI>
+<LI><A HREF="faq.html#defaultroutegone">Disappearing %defaultroute</A></LI>
+<LI><A HREF="faq.html#tcpdump.faq">TCPdump on the gateway shows strange
+ things</A></LI>
+<LI><A HREF="faq.html#no_trace">Traceroute does not show anything
+ between the gateways</A></LI>
+</UL>
+<LI><A HREF="faq.html#man4debug">Testing in stages</A></LI>
+<UL>
+<LI><A HREF="faq.html#nomanual">Manually keyed connections don't work</A>
+</LI>
+<LI><A HREF="faq.html#spi_error">One manual connection works, but second
+ one fails</A></LI>
+<LI><A HREF="faq.html#man_no_auto">Manual connections work, but
+ automatic keying doesn't</A></LI>
+<LI><A HREF="faq.html#nocomp">IPsec works, but connections using
+ compression fail</A></LI>
+<LI><A HREF="faq.html#pmtu.broken">Small packets work, but large
+ transfers fail</A></LI>
+<LI><A HREF="faq.html#subsub">Subnet-to-subnet works, but tests from the
+ gateways don't</A></LI>
+</UL>
+<LI><A HREF="faq.html#compile.faq">Compilation problems</A></LI>
+<UL>
+<LI><A HREF="faq.html#gmp.h_missing">gmp.h: No such file or directory</A>
+</LI>
+<LI><A HREF="faq.html#noVM">... virtual memory exhausted</A></LI>
+</UL>
+<LI><A HREF="faq.html#error">Interpreting error messages</A></LI>
+<UL>
+<LI><A HREF="faq.html#route-client">route-client (or host) exited with
+ status 7</A></LI>
+<LI><A HREF="faq.html#unreachable">SIOCADDRT:Network is unreachable</A></LI>
+<LI><A HREF="faq.html#modprobe">ipsec_setup: modprobe: Can't locate
+ module ipsec</A></LI>
+<LI><A HREF="faq.html#noKLIPS">ipsec_setup: Fatal error, kernel appears
+ to lack KLIPS</A></LI>
+<LI><A HREF="faq.html#noDNS">ipsec_setup: ... failure to fetch key for
+ ... from DNS</A></LI>
+<LI><A HREF="faq.html#dup_address">ipsec_setup: ... interfaces ... and
+ ... share address ...</A></LI>
+<LI><A HREF="faq.html#kflags">ipsec_setup: Cannot adjust kernel flags</A>
+</LI>
+<LI><A HREF="faq.html#message_num">Message numbers (MI3, QR1, et cetera)
+ in Pluto messages</A></LI>
+<LI><A HREF="faq.html#conn_name">Connection names in Pluto error
+ messages</A></LI>
+<LI><A HREF="faq.html#cantorient">Pluto: ... can't orient connection</A></LI>
+<LI><A HREF="faq.html#no.interface">... we have no ipsecN interface for
+ either end of this connection</A></LI>
+<LI><A HREF="faq.html#noconn">Pluto: ... no connection is known</A></LI>
+<LI><A HREF="faq.html#nosuit">Pluto: ... no suitable connection ...</A></LI>
+<LI><A HREF="faq.html#noconn.auth">Pluto: ... no connection has been
+ authorized</A></LI>
+<LI><A HREF="faq.html#noDESsupport">Pluto: ... OAKLEY_DES_CBC is not
+ supported.</A></LI>
+<LI><A HREF="faq.html#notransform">Pluto: ... no acceptable transform</A>
+</LI>
+<LI><A HREF="faq.html#rsasigkey">rsasigkey dumps core</A></LI>
+<LI><A HREF="faq.html#sig4">!Pluto failure!: ... exited with ... signal
+ 4</A></LI>
+<LI><A HREF="faq.html#econnrefused">ECONNREFUSED error message</A></LI>
+<LI><A HREF="faq.html#no_eroute">klips_debug: ... no eroute!</A></LI>
+<LI><A HREF="faq.html#SAused">... trouble writing to /dev/ipsec ... SA
+ already in use</A></LI>
+<LI><A HREF="faq.html#ignore">... ignoring ... payload</A></LI>
+<LI><A HREF="faq.html#unknown_rightcert">unknown parameter name
+ &quot;rightcert&quot;</A></LI>
+</UL>
+<LI><A HREF="faq.html#spam">Why don't you restrict the mailing lists to
+ reduce spam?</A></LI>
+</UL>
+<B><A HREF="manpages.html#manpages">FreeS/WAN manual pages</A></B>
+<UL>
+<LI><A HREF="manpages.html#man.file">Files</A></LI>
+<LI><A HREF="manpages.html#man.command">Commands</A></LI>
+<LI><A HREF="manpages.html#man.lib">Library routines</A></LI>
+</UL>
+<B><A HREF="firewall.html#firewall">FreeS/WAN and firewalls</A></B>
+<UL>
+<LI><A HREF="firewall.html#filters">Filtering rules for IPsec packets</A>
+</LI>
+<LI><A HREF="firewall.html#examplefw">Firewall configuration at boot</A></LI>
+<UL>
+<LI><A HREF="firewall.html#simple.rules">A simple set of rules</A></LI>
+<LI><A HREF="firewall.html#complex.rules">Other rules</A></LI>
+<LI><A HREF="firewall.html#rules.pub">Published rule sets</A></LI>
+</UL>
+<LI><A HREF="firewall.html#updown">Calling firewall scripts, named in
+ ipsec.conf(5)</A></LI>
+<UL>
+<LI><A HREF="firewall.html#pre_post">Scripts called at IPsec start and
+ stop</A></LI>
+<LI><A HREF="firewall.html#up_down">Scripts called at connection up and
+ down</A></LI>
+<LI><A HREF="firewall.html#ipchains.script">Scripts for ipchains or
+ iptables</A></LI>
+</UL>
+<LI><A HREF="firewall.html#NAT">A complication: IPsec vs. NAT</A></LI>
+<UL>
+<LI><A HREF="firewall.html#nat_ok">NAT on or behind the IPsec gateway
+ works</A></LI>
+<LI><A HREF="firewall.html#nat_bad">NAT between gateways is problematic</A>
+</LI>
+<LI><A HREF="firewall.html#NAT.ref">Other references on NAT and IPsec</A>
+</LI>
+</UL>
+<LI><A HREF="firewall.html#complications">Other complications</A></LI>
+<UL>
+<LI><A HREF="firewall.html#through">IPsec through the gateway</A></LI>
+<LI><A HREF="firewall.html#ipsec_only">Preventing non-IPsec traffic</A></LI>
+<LI><A HREF="firewall.html#unknowngate">Filtering packets from unknown
+ gateways</A></LI>
+</UL>
+<LI><A HREF="firewall.html#otherfilter">Other packet filters</A></LI>
+<UL>
+<LI><A HREF="firewall.html#ICMP">ICMP filtering</A></LI>
+<LI><A HREF="firewall.html#traceroute">UDP packets for traceroute</A></LI>
+<LI><A HREF="firewall.html#l2tp">UDP for L2TP</A></LI>
+</UL>
+<LI><A HREF="firewall.html#packets">How it all works: IPsec packet
+ details</A></LI>
+<UL>
+<LI><A HREF="firewall.html#noport">ESP and AH do not have ports</A></LI>
+<LI><A HREF="firewall.html#header">Header layout</A></LI>
+<LI><A HREF="firewall.html#dhr">DHR on the updown script</A></LI>
+</UL>
+</UL>
+<B><A HREF="trouble.html#trouble">Linux FreeS/WAN Troubleshooting Guide</A>
+</B>
+<UL>
+<LI><A HREF="trouble.html#overview">Overview</A></LI>
+<LI><A HREF="trouble.html#install">1. During Install</A></LI>
+<UL>
+<LI><A HREF="trouble.html#8_2_1">1.1 RPM install gotchas</A></LI>
+<LI><A HREF="trouble.html#8_2_2">1.2 Problems installing from source</A></LI>
+<LI><A HREF="trouble.html#install.check">1.3 Install checks</A></LI>
+<LI><A HREF="quickstart.html#oe.trouble">1.3 Troubleshooting OE</A></LI>
+</UL>
+<LI><A HREF="trouble.html#negotiation">2. During Negotiation</A></LI>
+<UL>
+<LI><A HREF="trouble.html#state">2.1 Determine Connection State</A></LI>
+<LI><A HREF="trouble.html#find.pluto.error">2.2 Finding error text</A></LI>
+<LI><A HREF="trouble.html#interpret.pluto.error">2.3 Interpreting a
+ Negotiation Error</A></LI>
+</UL>
+<LI><A HREF="trouble.html#use">3. Using a Connection</A></LI>
+<UL>
+<LI><A HREF="trouble.html#8_4_1">3.1 Orienting yourself</A></LI>
+<LI><A HREF="trouble.html#8_4_2">3.2 Those pesky configuration errors</A>
+</LI>
+<LI><A HREF="trouble.html#route.firewall">3.3 Check Routing and
+ Firewalling</A></LI>
+<LI><A HREF="trouble.html#sniff">3.4 When in doubt, sniff it out</A></LI>
+<LI><A HREF="trouble.html#find.use.error">3.5 Check your logs</A></LI>
+<LI><A HREF="trouble.html#bigpacket">3.6 More testing for the truly
+ thorough</A></LI>
+</UL>
+<LI><A HREF="trouble.html#prob.report">4. Problem Reporting</A></LI>
+<UL>
+<LI><A HREF="trouble.html#8_5_1">4.1 How to ask for help</A></LI>
+<LI><A HREF="trouble.html#8_5_2">4.2 Where to ask</A></LI>
+</UL>
+<LI><A HREF="trouble.html#notes">5. Additional Notes on Troubleshooting</A>
+</LI>
+<UL>
+<LI><A HREF="trouble.html#system.info">5.1 Information available on your
+ system</A></LI>
+<LI><A HREF="trouble.html#testgates"> 5.2 Testing between security
+ gateways</A></LI>
+<LI><A HREF="trouble.html#ifconfig1">5.3 ifconfig reports for KLIPS
+ debugging</A></LI>
+<LI><A HREF="trouble.html#gdb"> 5.4 Using GDB on Pluto</A></LI>
+</UL>
+</UL>
+<B><A HREF="compat.html#compat">Linux FreeS/WAN Compatibility Guide</A></B>
+<UL>
+<LI><A HREF="compat.html#spec">Implemented parts of the IPsec
+ Specification</A></LI>
+<UL>
+<LI><A HREF="compat.html#in">In Linux FreeS/WAN</A></LI>
+<LI><A HREF="compat.html#dropped">Deliberately omitted</A></LI>
+<LI><A HREF="compat.html#not">Not (yet) in Linux FreeS/WAN</A></LI>
+</UL>
+<LI><A HREF="compat.html#pfkey">Our PF-Key implementation</A></LI>
+<UL>
+<LI><A HREF="compat.html#pfk.port">PF-Key portability</A></LI>
+</UL>
+<LI><A HREF="compat.html#otherk">Kernels other than the latest 2.2.x and
+ 2.4.y</A></LI>
+<UL>
+<LI><A HREF="compat.html#kernel.2.0">2.0.x kernels</A></LI>
+<LI><A HREF="compat.html#kernel.production">2.2 and 2.4 kernels</A></LI>
+</UL>
+<LI><A HREF="compat.html#otherdist">Intel Linux distributions other than
+ Redhat</A></LI>
+<UL>
+<LI><A HREF="compat.html#rh7">Redhat 7.0</A></LI>
+<LI><A HREF="compat.html#suse">SuSE Linux</A></LI>
+<LI><A HREF="compat.html#slack">Slackware</A></LI>
+<LI><A HREF="compat.html#deb">Debian</A></LI>
+<LI><A HREF="compat.html#caldera">Caldera</A></LI>
+</UL>
+<LI><A HREF="compat.html#CPUs">CPUs other than Intel</A></LI>
+<UL>
+<LI><A HREF="compat.html# strongarm">Corel Netwinder (StrongARM CPU)</A></LI>
+<LI><A HREF="compat.html#yellowdog">Yellow Dog Linux on Power PC</A></LI>
+<LI><A HREF="compat.html#mklinux">Mklinux</A></LI>
+<LI><A HREF="compat.html#alpha">Alpha 64-bit processors</A></LI>
+<LI><A HREF="compat.html#SPARC">Sun SPARC processors</A></LI>
+<LI><A HREF="compat.html#mips">MIPS processors</A></LI>
+<LI><A HREF="compat.html#crusoe">Transmeta Crusoe</A></LI>
+<LI><A HREF="compat.html#coldfire">Motorola Coldfire</A></LI>
+</UL>
+<LI><A HREF="compat.html#multiprocessor">Multiprocessor machines</A></LI>
+<LI><A HREF="compat.html#hardware">Support for crypto hardware</A></LI>
+<LI><A HREF="compat.html#ipv6">IP version 6 (IPng)</A></LI>
+<UL>
+<LI><A HREF="compat.html#v6.back">IPv6 background</A></LI>
+</UL>
+</UL>
+<B><A HREF="interop.html#10">Interoperating with FreeS/WAN</A></B>
+<UL>
+<LI><A HREF="interop.html#10_1">Interop at a Glance</A></LI>
+<UL>
+<LI><A HREF="interop.html#10_1_1">Key</A></LI>
+</UL>
+<LI><A HREF="interop.html#10_2">Basic Interop Rules</A></LI>
+<LI><A HREF="interop.html#10_3">Longer Stories</A></LI>
+<UL>
+<LI><A HREF="interop.html#10_3_1">For More Compatible Implementations</A>
+</LI>
+<LI><A HREF="interop.html#10_3_2">For Other Implementations</A></LI>
+</UL>
+</UL>
+<B><A HREF="performance.html#performance">Performance of FreeS/WAN</A></B>
+<UL>
+<LI><A HREF="performance.html#pub.bench">Published material</A></LI>
+<LI><A HREF="performance.html#perf.estimate">Estimating CPU overheads</A>
+</LI>
+<UL>
+<LI><A HREF="performance.html#perf.more">Higher performance alternatives</A>
+</LI>
+<LI><A HREF="performance.html#11_2_2">Other considerations</A></LI>
+</UL>
+<LI><A HREF="performance.html#biggate">Many tunnels from a single
+ gateway</A></LI>
+<LI><A HREF="performance.html#low-end">Low-end systems</A></LI>
+<LI><A HREF="performance.html#klips.bench">Measuring KLIPS</A></LI>
+<LI><A HREF="performance.html#speed.compress">Speed with compression</A></LI>
+<LI><A HREF="performance.html#methods">Methods of measuring</A></LI>
+</UL>
+<B><A HREF="testing.html#test.freeswan">Testing FreeS/WAN</A></B>
+<UL>
+<LI><A HREF="testing.html#test.oe">Testing opportunistic connections</A></LI>
+<UL>
+<LI><A HREF="testing.html#12_1_1">Basic OE Test</A></LI>
+<LI><A HREF="testing.html#12_1_2">OE Gateway Test</A></LI>
+<LI><A HREF="testing.html#12_1_3">Additional OE tests</A></LI>
+</UL>
+<LI><A HREF="testing.html#test.uml">Testing with User Mode Linux</A></LI>
+<LI><A HREF="testing.html#testnet">Configuration for a testbed network</A>
+</LI>
+<UL>
+<LI><A HREF="testing.html#testbed">Testbed network</A></LI>
+<LI><A HREF="testing.html#tcpdump.test">Using packet sniffers in testing</A>
+</LI>
+</UL>
+<LI><A HREF="testing.html#verify.crypt">Verifying encryption</A></LI>
+<LI><A HREF="testing.html#mail.test">Mailing list pointers</A></LI>
+</UL>
+<B><A HREF="kernel.html#kernelconfig">Kernel configuration for FreeS/WAN</A>
+</B>
+<UL>
+<LI><A HREF="kernel.html#notall">Not everyone needs to worry about
+ kernel configuration</A></LI>
+<LI><A HREF="kernel.html#assume">Assumptions and notation</A></LI>
+<UL>
+<LI><A HREF="kernel.html#labels">Labels used</A></LI>
+</UL>
+<LI><A HREF="kernel.html#kernelopt">Kernel options for FreeS/WAN</A></LI>
+</UL>
+<B><A HREF="adv_config.html#adv_config">Other configuration
+ possibilities</A></B>
+<UL>
+<LI><A HREF="adv_config.html#thumb">Some rules of thumb about
+ configuration</A></LI>
+<UL>
+<LI><A HREF="adv_config.html#cheap.tunnel">Tunnels are cheap</A></LI>
+<LI><A HREF="adv_config.html#subnet.size">Subnet sizes</A></LI>
+<LI><A HREF="adv_config.html#example.more">Other network layouts</A></LI>
+</UL>
+<LI><A HREF="adv_config.html#choose">Choosing connection types</A></LI>
+<UL>
+<LI><A HREF="adv_config.html#man-auto">Manual vs. automatic keying</A></LI>
+<LI><A HREF="adv_config.html#auto-auth">Authentication methods for
+ auto-keying</A></LI>
+<LI><A HREF="adv_config.html#adv-pk">Advantages of public key methods</A>
+</LI>
+</UL>
+<LI><A HREF="adv_config.html#prodsecrets">Using shared secrets in
+ production</A></LI>
+<UL>
+<LI><A HREF="biblio.html#secrets">Putting secrets in ipsec.secrets(5)</A>
+</LI>
+<LI><A HREF="adv_config.html#securing.secrets">File security</A></LI>
+<LI><A HREF="adv_config.html#notroadshared">Shared secrets for road
+ warriors</A></LI>
+</UL>
+<LI><A HREF="adv_config.html#prodman">Using manual keying in production</A>
+</LI>
+<UL>
+<LI><A HREF="adv_config.html#ranbits">Creating keys with ranbits</A></LI>
+</UL>
+<LI><A HREF="adv_config.html#boot">Setting up connections at boot time</A>
+</LI>
+<LI><A HREF="adv_config.html#multitunnel">Multiple tunnels between the
+ same two gateways</A></LI>
+<UL>
+<LI><A HREF="adv_config.html#advroute">One tunnel plus advanced routing</A>
+</LI>
+</UL>
+<LI><A HREF="adv_config.html#opp.gate">An Opportunistic Gateway</A></LI>
+<UL>
+<LI><A HREF="adv_config.html#14_7_1">Start from full opportunism</A></LI>
+<LI><A HREF="adv_config.html#14_7_2">Reverse DNS TXT records for each
+ protected machine</A></LI>
+<LI><A HREF="adv_config.html#14_7_3">Publish your records</A></LI>
+<LI><A HREF="adv_config.html#14_7_4">...and test them</A></LI>
+<LI><A HREF="adv_config.html#14_7_5">No Configuration Needed</A></LI>
+</UL>
+<LI><A HREF="adv_config.html#extruded.config">Extruded Subnets</A></LI>
+<LI><A HREF="adv_config.html#roadvirt">Road Warrior with virtual IP
+ address</A></LI>
+<LI><A HREF="glossary.html#dynamic">Dynamic Network Interfaces</A></LI>
+<UL>
+<LI><A HREF="adv_config.html#basicdyn">Basics</A></LI>
+<LI><A HREF="adv_config.html#bootdyn">Boot Time</A></LI>
+<LI><A HREF="adv_config.html#changedyn">Change Time</A></LI>
+</UL>
+<LI><A HREF="adv_config.html#unencrypted">Unencrypted tunnels</A></LI>
+</UL>
+<B><A HREF="trouble.html#install">Installing FreeS/WAN</A></B>
+<UL>
+<LI><A HREF="install.html#15_1">Requirements</A></LI>
+<LI><A HREF="install.html#15_2">Choose your install method</A></LI>
+<LI><A HREF="install.html#15_3">FreeS/WAN ships with some Linuxes</A></LI>
+<UL>
+<LI><A HREF="install.html#15_3_1">FreeS/WAN may be altered...</A></LI>
+<LI><A HREF="install.html#15_3_2">You might need to create an
+ authentication keypair</A></LI>
+<LI><A HREF="install.html#15_3_3">Start and test FreeS/WAN</A></LI>
+</UL>
+<LI><A HREF="install.html#15_4">RPM install</A></LI>
+<UL>
+<LI><A HREF="install.html#15_4_1">Download RPMs</A></LI>
+<LI><A HREF="install.html#15_4_2">For freeswan.org RPMs: check
+ signatures</A></LI>
+<LI><A HREF="install.html#15_4_3">Install the RPMs</A></LI>
+<LI><A HREF="install.html#15_4_4">Start and Test FreeS/WAN</A></LI>
+</UL>
+<LI><A HREF="install.html#15_5">Install from Source</A></LI>
+<UL>
+<LI><A HREF="install.html#15_5_1">Decide what functionality you need</A></LI>
+<LI><A HREF="install.html#15_5_2">Download FreeS/WAN</A></LI>
+<LI><A HREF="install.html#15_5_3">For freeswan.org source: check its
+ signature</A></LI>
+<LI><A HREF="install.html#15_5_4">Untar, unzip</A></LI>
+<LI><A HREF="install.html#15_5_5">Patch if desired</A></LI>
+<LI><A HREF="install.html#15_5_6">... and Make</A></LI>
+</UL>
+<LI><A HREF="install.html#15_6">Start FreeS/WAN and test your install</A>
+</LI>
+<LI><A HREF="install.html#15_7">Test your install</A></LI>
+<LI><A HREF="install.html#15_8">Making FreeS/WAN play well with others</A>
+</LI>
+<LI><A HREF="install.html#15_9">Configure for your needs</A></LI>
+</UL>
+<B><A HREF="config.html#config">How to configure FreeS/WAN</A></B>
+<UL>
+<LI><A HREF="config.html#16_1">Requirements</A></LI>
+<LI><A HREF="config.html#config.netnet">Net-to-Net connection</A></LI>
+<UL>
+<LI><A HREF="config.html#netnet.info.ex">Gather information</A></LI>
+<LI><A HREF="config.html#16_2_2">Edit /etc/ipsec.conf</A></LI>
+<LI><A HREF="config.html#16_2_3">Start your connection</A></LI>
+<LI><A HREF="config.html#16_2_4">Do not MASQ or NAT packets to be
+ tunneled</A></LI>
+<LI><A HREF="config.html#16_2_5">Test your connection</A></LI>
+<LI><A HREF="config.html#16_2_6">Finishing touches</A></LI>
+</UL>
+<LI><A HREF="config.html#config.rw">Road Warrior Configuration</A></LI>
+<UL>
+<LI><A HREF="config.html#rw.info.ex">Gather information</A></LI>
+<LI><A HREF="config.html#16_3_2">Customize /etc/ipsec.conf</A></LI>
+<LI><A HREF="config.html#16_3_3">Start your connection</A></LI>
+<LI><A HREF="config.html#16_3_4">Do not MASQ or NAT packets to be
+ tunneled</A></LI>
+<LI><A HREF="config.html#16_3_5">Test your connection</A></LI>
+<LI><A HREF="config.html#16_3_6">Finishing touches</A></LI>
+<LI><A HREF="config.html#16_3_7">Multiple Road Warriors</A></LI>
+</UL>
+<LI><A HREF="config.html#16_4">What next?</A></LI>
+</UL>
+<B><A HREF="background.html#background">Linux FreeS/WAN background</A></B>
+<UL>
+<LI><A HREF="background.html#dns.background">Some DNS background</A></LI>
+<UL>
+<LI><A HREF="background.html#forward.reverse">Forward and reverse maps</A>
+</LI>
+<LI><A HREF="background.html#17_1_2">Hierarchy and delegation</A></LI>
+<LI><A HREF="background.html#17_1_3">Syntax of DNS records</A></LI>
+<LI><A HREF="background.html#17_1_4">Cacheing, TTL and propagation delay</A>
+</LI>
+</UL>
+<LI><A HREF="background.html#MTU.trouble">Problems with packet
+ fragmentation</A></LI>
+<LI><A HREF="background.html#nat.background">Network address translation
+ (NAT)</A></LI>
+<UL>
+<LI><A HREF="background.html#17_3_1">NAT to non-routable addresses</A></LI>
+<LI><A HREF="background.html#17_3_2">NAT to routable addresses</A></LI>
+</UL>
+</UL>
+<B><A HREF="user_examples.html#user.examples">FreeS/WAN script examples</A>
+</B>
+<UL>
+<LI><A HREF="user_examples.html#poltorak">Poltorak's Firewall script</A></LI>
+</UL>
+<B><A HREF="makecheck.html#makecheck">How to configure to use &quot;make
+ check&quot;</A></B>
+<UL>
+<LI><A HREF="makecheck.html#19_1">What is &quot;make check&quot;</A></LI>
+<LI><A HREF="makecheck.html#19_2">Running &quot;make check&quot;</A></LI>
+</UL>
+<B><A HREF="makecheck.html#20">How to write a &quot;make check&quot; test</A></B>
+<UL>
+<LI><A HREF="makecheck.html#20_1">Structure of a test</A></LI>
+<LI><A HREF="makecheck.html#20_2">The TESTLIST</A></LI>
+<LI><A HREF="makecheck.html#20_3">Test kinds</A></LI>
+<LI><A HREF="makecheck.html#20_4">Common parameters</A></LI>
+<LI><A HREF="makecheck.html#20_5">KLIPStest paramaters</A></LI>
+<LI><A HREF="makecheck.html#20_6">mkinsttest paramaters</A></LI>
+<LI><A HREF="makecheck.html#20_7">rpm_build_install_test paramaters</A></LI>
+<LI><A HREF="makecheck.html#20_8">libtest paramaters</A></LI>
+<LI><A HREF="makecheck.html#20_9">umlplutotest paramaters</A></LI>
+<LI><A HREF="makecheck.html#20_10">umlXhost parameters</A></LI>
+<LI><A HREF="makecheck.html#20_11">kernel_patch_test paramaters</A></LI>
+<LI><A HREF="makecheck.html#20_12">module_compile paramaters</A></LI>
+</UL>
+<B><A HREF="makecheck.html#21">Current pitfalls</A></B>
+<BR>
+<BR><B><A HREF="umltesting.html#umltesting">User-Mode-Linux Testing
+ guide</A></B>
+<UL>
+<LI><A HREF="umltesting.html#22_1">Preliminary Notes on BIND</A></LI>
+<LI><A HREF="umltesting.html#22_2">Steps to Install UML for FreeS/WAN</A>
+</LI>
+</UL>
+<B><A HREF="umltesting.html#23">Debugging the kernel with GDB</A></B>
+<UL>
+<LI><A HREF="umltesting.html#23_1">Other notes about debugging</A></LI>
+</UL>
+<B><A HREF="umltesting.html#24">User-Mode-Linux mysteries</A></B>
+<BR>
+<BR><B><A HREF="umltesting.html#25">Getting more info from uml_netjig</A>
+</B>
+<BR>
+<BR><B><A HREF="politics.html#politics">History and politics of
+ cryptography</A></B>
+<UL>
+<LI><A HREF="politics.html#intro.politics">Introduction</A></LI>
+<UL>
+<LI><A HREF="politics.html#26_1_1">History</A></LI>
+<LI><A HREF="politics.html#intro.poli">Politics</A></LI>
+<LI><A HREF="politics.html#26_1_3">Links</A></LI>
+<LI><A HREF="politics.html#26_1_4">Outline of this section</A></LI>
+</UL>
+<LI><A HREF="politics.html#leader">From our project leader</A></LI>
+<UL>
+<LI><A HREF="politics.html#gilmore">Swan: Securing the Internet against
+ Wiretapping</A></LI>
+<LI><A HREF="politics.html#policestate">Stopping wholesale monitoring</A>
+</LI>
+</UL>
+<LI><A HREF="politics.html#weak">Government promotion of weak crypto</A></LI>
+<UL>
+<LI><A HREF="politics.html#escrow">Escrowed encryption</A></LI>
+<LI><A HREF="politics.html#shortkeys">Limited key lengths</A></LI>
+</UL>
+<LI><A HREF="politics.html#exlaw">Cryptography Export Laws</A></LI>
+<UL>
+<LI><A HREF="politics.html#USlaw">US Law</A></LI>
+<LI><A HREF="politics.html#wrong">What's wrong with restrictions on
+ cryptography</A></LI>
+<LI><A HREF="politics.html#Wassenaar">The Wassenaar Arrangement</A></LI>
+<LI><A HREF="politics.html#status">Export status of Linux FreeS/WAN</A></LI>
+<LI><A HREF="politics.html#help">Help spread IPsec around</A></LI>
+</UL>
+<LI><A HREF="politics.html#desnotsecure">DES is Not Secure</A></LI>
+<UL>
+<LI><A HREF="politics.html#deshware">Dedicated hardware breaks DES in a
+ few days</A></LI>
+<LI><A HREF="politics.html#spooks">Spooks may break DES faster yet</A></LI>
+<LI><A HREF="politics.html#desnet">Networks break DES in a few weeks</A></LI>
+<LI><A HREF="politics.html#no_des">We disable DES</A></LI>
+<LI><A HREF="politics.html#40joke">40-bits is laughably weak</A></LI>
+<LI><A HREF="politics.html#altdes">Triple DES is almost certainly secure</A>
+</LI>
+<LI><A HREF="politics.html#aes.ipsec">AES in IPsec</A></LI>
+</UL>
+<LI><A HREF="politics.html#press">Press coverage of Linux FreeS/WAN:</A></LI>
+<UL>
+<LI><A HREF="politics.html#26_6_1">FreeS/WAN 1.0 press</A></LI>
+<LI><A HREF="faq.html#release">Press release for version 1.0</A></LI>
+</UL>
+</UL>
+<B><A HREF="ipsec.html#ipsec.detail">The IPsec protocols</A></B>
+<UL>
+<LI><A HREF="ipsec.html#27_1">Protocols and phases</A></LI>
+<LI><A HREF="ipsec.html#others">Applying IPsec</A></LI>
+<UL>
+<LI><A HREF="ipsec.html#advantages">Advantages of IPsec</A></LI>
+<LI><A HREF="ipsec.html#limitations">Limitations of IPsec</A></LI>
+<LI><A HREF="ipsec.html#uses">IPsec is a general mechanism for securing
+ IP</A></LI>
+<LI><A HREF="ipsec.html#authonly">Using authentication without
+ encryption</A></LI>
+<LI><A HREF="ipsec.html#encnoauth">Encryption without authentication is
+ dangerous</A></LI>
+<LI><A HREF="ipsec.html#multilayer">Multiple layers of IPsec processing
+ are possible</A></LI>
+<LI><A HREF="ipsec.html#traffic.resist">Resisting traffic analysis</A></LI>
+</UL>
+<LI><A HREF="ipsec.html#primitives">Cryptographic components</A></LI>
+<UL>
+<LI><A HREF="ipsec.html#block.cipher">Block ciphers</A></LI>
+<LI><A HREF="ipsec.html#hash.ipsec">Hash functions</A></LI>
+<LI><A HREF="ipsec.html#DH.keying">Diffie-Hellman key agreement</A></LI>
+<LI><A HREF="ipsec.html#RSA.auth">RSA authentication</A></LI>
+</UL>
+<LI><A HREF="ipsec.html#structure">Structure of IPsec</A></LI>
+<UL>
+<LI><A HREF="ipsec.html#IKE.ipsec">IKE (Internet Key Exchange)</A></LI>
+<LI><A HREF="ipsec.html#services">IPsec Services, AH and ESP</A></LI>
+<LI><A HREF="ipsec.html#AH.ipsec">The Authentication Header (AH)</A></LI>
+<LI><A HREF="ipsec.html#ESP.ipsec">Encapsulated Security Payload (ESP)</A>
+</LI>
+</UL>
+<LI><A HREF="ipsec.html#modes">IPsec modes</A></LI>
+<UL>
+<LI><A HREF="ipsec.html#tunnel.ipsec">Tunnel mode</A></LI>
+<LI><A HREF="ipsec.html#transport.ipsec">Transport mode</A></LI>
+</UL>
+<LI><A HREF="ipsec.html#parts">FreeS/WAN parts</A></LI>
+<UL>
+<LI><A HREF="ipsec.html#KLIPS.ipsec">KLIPS: Kernel IPsec Support</A></LI>
+<LI><A HREF="ipsec.html#Pluto.ipsec">The Pluto daemon</A></LI>
+<LI><A HREF="ipsec.html#command">The ipsec(8) command</A></LI>
+<LI><A HREF="ipsec.html#ipsec.conf">Linux FreeS/WAN configuration file</A>
+</LI>
+</UL>
+<LI><A HREF="ipsec.html#key">Key management</A></LI>
+<UL>
+<LI><A HREF="ipsec.html#current">Currently Implemented Methods</A></LI>
+<LI><A HREF="ipsec.html#notyet">Methods not yet implemented</A></LI>
+</UL>
+</UL>
+<B><A HREF="mail.html#lists">Mailing lists and newsgroups</A></B>
+<UL>
+<LI><A HREF="mail.html#list.fs">Mailing lists about FreeS/WAN</A></LI>
+<UL>
+<LI><A HREF="mail.html#projlist">The project mailing lists</A></LI>
+<LI><A HREF="mail.html#archive">Archives of the lists</A></LI>
+</UL>
+<LI><A HREF="mail.html#indexes">Indexes of mailing lists</A></LI>
+<LI><A HREF="mail.html#otherlists">Lists for related software and topics</A>
+</LI>
+<UL>
+<LI><A HREF="mail.html#28_3_1">Products that include FreeS/WAN</A></LI>
+<LI><A HREF="mail.html#linux.lists">Linux mailing lists</A></LI>
+<LI><A HREF="mail.html#ietf">Lists for IETF working groups</A></LI>
+<LI><A HREF="mail.html#other">Other mailing lists</A></LI>
+</UL>
+<LI><A HREF="mail.html#newsgroups">Usenet newsgroups</A></LI>
+</UL>
+<B><A HREF="web.html#weblink">Web links</A></B>
+<UL>
+<LI><A HREF="web.html#freeswan">The Linux FreeS/WAN Project</A></LI>
+<UL>
+<LI><A HREF="web.html#patch">Add-ons and patches for FreeS/WAN</A></LI>
+<LI><A HREF="web.html#dist">Distributions including FreeS/WAN</A></LI>
+<LI><A HREF="web.html#used">Things FreeS/WAN uses or could use</A></LI>
+<LI><A HREF="web.html#alternatives">Other approaches to VPNs for Linux</A>
+</LI>
+</UL>
+<LI><A HREF="web.html#ipsec.link">The IPsec Protocols</A></LI>
+<UL>
+<LI><A HREF="web.html#general">General IPsec or VPN information</A></LI>
+<LI><A HREF="trouble.html#overview">IPsec overview documents or slide
+ sets</A></LI>
+<LI><A HREF="web.html#otherlang">IPsec information in languages other
+ than English</A></LI>
+<LI><A HREF="web.html#RFCs1">RFCs and other reference documents</A></LI>
+<LI><A HREF="web.html#analysis">Analysis and critiques of IPsec
+ protocols</A></LI>
+<LI><A HREF="web.html#IP.background">Background information on IP</A></LI>
+</UL>
+<LI><A HREF="web.html#implement">IPsec Implementations</A></LI>
+<UL>
+<LI><A HREF="web.html#linuxprod">Linux products</A></LI>
+<LI><A HREF="web.html#router">IPsec in router products</A></LI>
+<LI><A HREF="web.html#fw.web">IPsec in firewall products</A></LI>
+<LI><A HREF="web.html#ipsecos">Operating systems with IPsec support</A></LI>
+<LI><A HREF="web.html#29_3_5">IPsec on network cards</A></LI>
+<LI><A HREF="web.html#opensource">Open source IPsec implementations</A></LI>
+<LI><A HREF="web.html#interop.web">Interoperability</A></LI>
+</UL>
+<LI><A HREF="web.html#linux.link">Linux links</A></LI>
+<UL>
+<LI><A HREF="web.html#linux.basic">Basic and tutorial Linux information</A>
+</LI>
+<LI><A HREF="web.html#general">General Linux sites</A></LI>
+<LI><A HREF="web.html#docs.ldp">Documentation</A></LI>
+<LI><A HREF="web.html#advroute.web">Advanced routing</A></LI>
+<LI><A HREF="web.html#linsec">Security for Linux</A></LI>
+<LI><A HREF="web.html#firewall.linux">Linux firewalls</A></LI>
+<LI><A HREF="web.html#linux.misc">Miscellaneous Linux information</A></LI>
+</UL>
+<LI><A HREF="web.html#crypto.link">Crypto and security links</A></LI>
+<UL>
+<LI><A HREF="web.html#security">Crypto and security resources</A></LI>
+<LI><A HREF="web.html#policy">Cryptography law and policy</A></LI>
+<LI><A HREF="web.html#crypto.tech">Cryptography technical information</A>
+</LI>
+<LI><A HREF="web.html#compsec">Computer and network security</A></LI>
+<LI><A HREF="web.html#people">Links to home pages</A></LI>
+</UL>
+</UL>
+<B><A HREF="glossary.html#ourgloss">Glossary for the Linux FreeS/WAN
+ project</A></B>
+<UL>
+<LI><A HREF="glossary.html#jump">Jump to a letter in the glossary</A></LI>
+<LI><A HREF="glossary.html#gloss">Other glossaries</A></LI>
+<LI><A HREF="glossary.html#definitions">Definitions</A></LI>
+</UL>
+<B><A HREF="biblio.html#biblio">Bibliography for the Linux FreeS/WAN
+ project</A></B>
+<BR>
+<BR><B><A HREF="rfc.html#RFC">IPsec RFCs and related documents</A></B>
+<UL>
+<LI><A HREF="rfc.html#RFCfile">The RFCs.tar.gz Distribution File</A></LI>
+<LI><A HREF="rfc.html#sources">Other sources for RFCs &amp; Internet drafts</A>
+</LI>
+<UL>
+<LI><A HREF="rfc.html#RFCdown">RFCs</A></LI>
+<LI><A HREF="rfc.html#drafts">Internet Drafts</A></LI>
+<LI><A HREF="rfc.html#FIPS1">FIPS standards</A></LI>
+</UL>
+<LI><A HREF="rfc.html#RFCs.tar.gz">What's in the RFCs.tar.gz bundle?</A></LI>
+<UL>
+<LI><A HREF="rfc.html#rfc.ov">Overview RFCs</A></LI>
+<LI><A HREF="rfc.html#basic.prot">Basic protocols</A></LI>
+<LI><A HREF="rfc.html#key.ike">Key management</A></LI>
+<LI><A HREF="rfc.html#rfc.detail">Details of various things used</A></LI>
+<LI><A HREF="rfc.html#rfc.ref">Older RFCs which may be referenced</A></LI>
+<LI><A HREF="rfc.html#rfc.dns">RFCs for secure DNS service, which IPsec
+ may use</A></LI>
+<LI><A HREF="rfc.html#rfc.exp">RFCs labelled &quot;experimental&quot;</A></LI>
+<LI><A HREF="rfc.html#rfc.rel">Related RFCs</A></LI>
+</UL>
+</UL>
+<B><A HREF="roadmap.html#roadmap">Distribution Roadmap: What's Where in
+ Linux FreeS/WAN</A></B>
+<UL>
+<LI><A HREF="roadmap.html#top">Top directory</A></LI>
+<LI><A HREF="roadmap.html#doc">Documentation</A></LI>
+<LI><A HREF="roadmap.html#klips.roadmap">KLIPS: kernel IP security</A></LI>
+<LI><A HREF="roadmap.html#pluto.roadmap">Pluto key and connection
+ management daemon</A></LI>
+<LI><A HREF="roadmap.html#utils">Utils</A></LI>
+<LI><A HREF="roadmap.html#lib">Libraries</A></LI>
+<UL>
+<LI><A HREF="roadmap.html#fswanlib">FreeS/WAN Library</A></LI>
+<LI><A HREF="roadmap.html#otherlib">Imported Libraries</A></LI>
+</UL>
+</UL>
+<B><A HREF="umltesting.html#umltesting">User-Mode-Linux Testing guide</A>
+</B>
+<UL>
+<LI><A HREF="umltesting.html#34_1">Preliminary Notes on BIND</A></LI>
+<LI><A HREF="umltesting.html#34_2">Steps to Install UML for FreeS/WAN</A>
+</LI>
+</UL>
+<B><A HREF="umltesting.html#35">Debugging the kernel with GDB</A></B>
+<UL>
+<LI><A HREF="umltesting.html#35_1">Other notes about debugging</A></LI>
+</UL>
+<B><A HREF="umltesting.html#36">User-Mode-Linux mysteries</A></B>
+<BR>
+<BR><B><A HREF="umltesting.html#37">Getting more info from uml_netjig</A>
+</B>
+<BR>
+<BR><B><A HREF="makecheck.html#makecheck">How to configure to use &quot;make
+ check&quot;</A></B>
+<UL>
+<LI><A HREF="makecheck.html#38_1">What is &quot;make check&quot;</A></LI>
+<LI><A HREF="makecheck.html#38_2">Running &quot;make check&quot;</A></LI>
+</UL>
+<B><A HREF="makecheck.html#39">How to write a &quot;make check&quot; test</A></B>
+<UL>
+<LI><A HREF="makecheck.html#39_1">Structure of a test</A></LI>
+<LI><A HREF="makecheck.html#39_2">The TESTLIST</A></LI>
+<LI><A HREF="makecheck.html#39_3">Test kinds</A></LI>
+<LI><A HREF="makecheck.html#39_4">Common parameters</A></LI>
+<LI><A HREF="makecheck.html#39_5">KLIPStest paramaters</A></LI>
+<LI><A HREF="makecheck.html#39_6">mkinsttest paramaters</A></LI>
+<LI><A HREF="makecheck.html#39_7">rpm_build_install_test paramaters</A></LI>
+<LI><A HREF="makecheck.html#39_8">libtest paramaters</A></LI>
+<LI><A HREF="makecheck.html#39_9">umlplutotest paramaters</A></LI>
+<LI><A HREF="makecheck.html#39_10">umlXhost parameters</A></LI>
+<LI><A HREF="makecheck.html#39_11">kernel_patch_test paramaters</A></LI>
+<LI><A HREF="makecheck.html#39_12">module_compile paramaters</A></LI>
+</UL>
+<B><A HREF="makecheck.html#40">Current pitfalls</A></B>
+<BR>
+<BR><B><A HREF="nightly.html#nightly">Nightly regression testing</A></B>
+<BR>
+<BR><B><A HREF="nightly.html#nightlyhowto">How to setup the nightly
+ build</A></B>
+<UL>
+<LI><A HREF="nightly.html#42_1"> Files you need to know about</A></LI>
+<LI><A HREF="nightly.html#42_2">Configuring freeswan-regress-env.sh</A></LI>
+</UL>
+</BODY>
+</HTML>
diff --git a/doc/trouble.html b/doc/trouble.html
new file mode 100644
index 000000000..2123f3805
--- /dev/null
+++ b/doc/trouble.html
@@ -0,0 +1,706 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
+H5 { font-family: sans-serif }
+H6 { font-family: sans-serif }
+SUB { font-size: smaller }
+SUP { font-size: smaller }
+PRE { font-family: monospace }
+--></STYLE>
+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="firewall.html">Previous</A>
+<A HREF="compat.html">Next</A>
+<HR>
+<H1><A NAME="trouble"></A>Linux FreeS/WAN Troubleshooting Guide</H1>
+<H2><A NAME="overview"></A>Overview</H2>
+<P> This document covers several general places where you might have a
+ problem:</P>
+<OL>
+<LI><A HREF="#install">During install</A>.</LI>
+<LI><A HREF="#negotiation">During the negotiation process</A>.</LI>
+<LI><A HREF="#use">Using an established connection</A>.</LI>
+</OL>
+<P>This document also contains<A HREF="#notes"> notes</A> which expand
+ on points made in these sections, and tips for<A HREF="#prob.report">
+ problem reporting</A>. If the other end of your connection is not
+ FreeS/WAN, you'll also want to read our<A HREF="interop.html#interop.problem">
+ interoperation</A> document.</P>
+<H2><A NAME="install"></A>1. During Install</H2>
+<H3><A NAME="8_2_1">1.1 RPM install gotchas</A></H3>
+<P>With the RPM method:</P>
+<UL>
+<LI>Be sure you have installed both the userland tools and the kernel
+ components. One will not work without the other. For example, when
+ using FreeS/WAN-produced RPMs for our 2.04 release, you need both:
+<PRE>    freeswan-userland-2.04_2.4.20_20.9-0.i386.rpm
+    freeswan-module-2.04_2.4.20_20.9-0.i386.rpm
+</PRE>
+</LI>
+</UL>
+<H3><A NAME="8_2_2">1.2 Problems installing from source</A></H3>
+<P>When installing from source, you may find these problems:</P>
+<UL>
+<LI>Missing library. See<A HREF="faq.html#gmp.h_missing"> this</A> FAQ.</LI>
+<LI>Missing utilities required for compile. See this<A HREF="install.html#tool.lib">
+ checklist</A>.</LI>
+<LI>Kernel version incompatibility. See<A HREF="faq.html#k.versions">
+ this</A> FAQ.</LI>
+<LI>Another compile problem. Find information in the out.* files, ie.
+ out.kpatch, out.kbuild, created at compile time in the top-level Linux
+ FreeS/WAN directory. Error messages generated by KLIPS during the boot
+ sequence are accessible with the<VAR> dmesg</VAR> command.
+<BR> Check the list archives and the List in Brief to see if this is a
+ known issue. If it is not, report it to the bugs list as described in
+ our<A HREF="#prob.report"> problem reporting</A> section. In some
+ cases, you may be asked to provide debugging information using gdb;
+ details<A HREF="#gdb"> below</A>.</LI>
+<LI>If your kernel compiles but you fail to install your new
+ FreeS/WAN-enabled kernel, review the sections on<A HREF="install.html#newk">
+ installing the patched kernel</A>, and<A HREF="install.html#testinstall">
+ testing</A> to see if install succeeded.</LI>
+</UL>
+<H3><A NAME="install.check"></A>1.3 Install checks</H3>
+<P><VAR>ipsec verify</VAR> checks a number of FreeS/WAN essentials. Here
+ are some hints on what do to when your system doesn't check out:</P>
+<P></P>
+<TABLE border="1">
+<TR><TD><STRONG>Problem</STRONG></TD><TD><STRONG>Status</STRONG></TD><TD>
+<STRONG>Action</STRONG></TD></TR>
+<TR><TD><VAR>ipsec</VAR> not on-path</TD><TD>&nbsp;</TD><TD>
+<P>Add<VAR> /usr/local/sbin</VAR> to your PATH.</P>
+</TD></TR>
+<TR><TD>Missing KLIPS support</TD><TD><FONT COLOR="#FF0000">critical</FONT>
+</TD><TD>See<A HREF="faq.html#noKLIPS"> this FAQ.</A></TD></TR>
+<TR><TD>No RSA private key</TD><TD>&nbsp;</TD><TD>
+<P>Follow<A HREF="install.html#genrsakey"> these instructions</A> to
+ create an RSA key pair for your host. RSA keys are:</P>
+<UL>
+<LI>required for opportunistic encryption, and</LI>
+<LI>our preferred method to authenticate pre-configured connections.</LI>
+</UL>
+</TD></TR>
+<TR><TD><VAR>pluto</VAR> not running</TD><TD><FONT COLOR="#FF0000">
+critical</FONT></TD><TD>
+<PRE>service ipsec start</PRE>
+</TD></TR>
+<TR><TD>No port 500 hole</TD><TD><FONT COLOR="#FF0000">critical</FONT></TD><TD>
+Open port 500 for IKE negotiation.</TD></TR>
+<TR><TD>Port 500 check N/A</TD><TD>&nbsp;</TD><TD>Check that port 500 is open
+ for IKE negotiation.</TD></TR>
+<TR><TD>Failed DNS checks</TD><TD>&nbsp;</TD><TD>Opportunistic encryption
+ requires information from DNS. To set this up, see<A HREF="quickstart.html#opp.setup">
+ our instructions</A>.</TD></TR>
+<TR><TD>No public IP address</TD><TD>&nbsp;</TD><TD>Check that the interface
+ which you want to protect with IPSec is up and running.</TD></TR>
+</TABLE>
+<H3><A NAME="oe.trouble"></A>1.3 Troubleshooting OE</H3>
+<P>OE should work with no local configuration, if you have posted DNS
+ TXT records according to the instructions in our<A HREF="quickstart.html">
+ quickstart guide</A>. If you encounter trouble, try these hints. We
+ welcome additional hints via the<A HREF="mail.html"> users' mailing
+ list</A>.</P>
+<TABLE border="1">
+<TR><TD><STRONG>Symptom</STRONG></TD><TD><STRONG>Problem</STRONG></TD><TD>
+<STRONG>Action</STRONG></TD></TR>
+<TR><TD> You're running FreeS/WAN 2.01 (or later), and initiating a
+ connection to FreeS/WAN 2.00 (or earlier). In your logs, you see a
+ message like:
+<PRE>no RSA public key known for '192.0.2.13';
+DNS search for KEY failed (no KEY record
+for 13.2.0.192.in-addr.arpa.)</PRE>
+ The older FreeS/WAN logs no error.</TD><TD><A NAME="oe.trouble.flagday">
+</A> A protocol level incompatibility between 2.01 (or later) and 2.00
+ (or earlier) causes this error. It occurs when a FreeS/WAN 2.01 (or
+ later) box for which no KEY record is posted attempts to initiate an OE
+ connection to older FreeS/WAN versions (2.00 and earlier). Note that
+ older versions can initiate to newer versions without this error.</TD><TD>
+If you control the peer host, upgrade its FreeS/WAN to 2.01 (or later),
+ and post new style TXT records for it. If not, but if you know its
+ sysadmin, perhaps a quick note is in order. If neither option is
+ possible, you can ease the transition by posting an old style KEY
+ record (created with a command like &quot;ipsec&nbsp;showhostkey&nbsp;--key&quot;) to the
+ reverse map for the FreeS/WAN 2.01 (or later) box.</TD></TR>
+<TR><TD>OE host is very slow to contact other hosts.</TD><TD>Slow DNS
+ service while running OE.</TD><TD>It's a good idea to run a caching DNS
+ server on your OE host, as outlined in<A HREF="http://lists.freeswan.org/pipermail/design/2003-January/004205.html">
+ this mailing list message</A>. If your DNS servers are elsewhere, put
+ their IPs in the<VAR> clear</VAR> policy group, and re-read groups with
+<PRE>ipsec auto --rereadgroups</PRE>
+</TD></TR>
+<TR><TD>
+<PRE>Can't Opportunistically initiate for
+192.0.2.2 to 192.0.2.3: no TXT record
+for 13.2.0.192.in-addr.arpa.</PRE>
+</TD><TD>Peer is not set up for OE.</TD><TD>
+<P>None. Plenty of hosts on the Internet do not run OE. If, however, you
+ have set OE up on that peer, this may indicate that you need to wait up
+ to 48 hours for its DNS records to propagate.</P>
+</TD></TR>
+<TR><TD><VAR>ipsec verify</VAR> does not find DNS records:
+<PRE>...
+Looking for TXT in forward map:
+                xy.example.com...[FAILED]
+Looking for TXT in reverse map...[FAILED]
+...</PRE>
+ You also experience authentication failure:
+<BR>
+<PRE>Possible authentication failure:
+no acceptable response to our
+first encrypted message</PRE>
+</TD><TD>DNS records are not posted or have not propagated.</TD><TD>Did
+ you post the DNS records necessary for OE? If not, do so using the
+ instructions in our<A HREF="quickstart.html#quickstart"> quickstart
+ guide</A>. If so, wait up to 48 hours for the DNS records to propagate.</TD>
+</TR>
+<TR><TD><VAR>ipsec verify</VAR> does not find DNS records, and you
+ experience authentication failure.</TD><TD>For iOE, your ID does not
+ match location of forward DNS record.</TD><TD>In<VAR> config setup</VAR>
+, change<VAR> myid=</VAR> to match the forward DNS where you posted the
+ record. Restart FreeS/WAN. For reference, see our<A HREF="quickstart.html#opp.client">
+ iOE instructions</A>.</TD></TR>
+<TR><TD><VAR>ipsec verify</VAR> finds DNS records, yet there is still
+ authentication failure. ( ? )</TD><TD>DNS records are malformed.</TD><TD>
+Re-create the records and send new copies to your DNS administrator.</TD>
+</TR>
+<TR><TD><VAR>ipsec verify</VAR> finds DNS records, yet there is still
+ authentication failure. ( ? )</TD><TD>DNS records show different keys
+ for a gateway vs. its subnet hosts.</TD><TD>All TXT records for boxes
+ protected by an OE gateway must contain the gateway's public key.
+ Re-create and re-post any incorrect records using<A HREF="quickstart.html#opp.incoming">
+ these instructions</A>.</TD></TR>
+<TR><TD>OE gateway loses connectivity to its subnet. The gateway's
+ routing table shows routes to the subnet through IPsec interfaces.</TD><TD>
+The subnet is part of the<VAR> private</VAR> or<VAR> block</VAR> policy
+ group on the gateway.</TD><TD>Remove the subnet from the group, and
+ reread groups with
+<PRE>ipsec auto --rereadgroups</PRE>
+</TD></TR>
+<TR><TD>OE does not work to hosts on the local LAN.</TD><TD>This is a
+ known issue.</TD><TD>See<A HREF="opportunism.known-issues"> this list</A>
+ of known issues with OE.</TD></TR>
+<TR><TD>FreeS/WAN does not seem to be executing your default policy. In
+ your logs, you see a message like:
+<PRE>/etc/ipsec.d/policies/iprivate-or-clear&quot;
+line 14: subnet &quot;0.0.0.0/0&quot;,
+source 192.0.2.13/32,
+already &quot;private-or-clear&quot;</PRE>
+</TD><TD><A HREF="glossary.html#fullnet">Fullnet</A> in a policy group
+ file defines your default policy. Fullnet should normally be present in
+ only one policy group file. The fine print: you can have two default
+ policies defined so long as they protect different local endpoints
+ (e.g. the FreeS/WAN gateway and a subnet).</TD><TD> Find all policies
+ which contain fullnet with:
+<BR>
+<PRE>grep -F 0.0.0.0/0 /etc/ipsec.d/policies/*</PRE>
+ then remove the unwanted occurrence(s).</TD></TR>
+</TABLE>
+<H2><A NAME="negotiation"></A>2. During Negotiation</H2>
+<P>When you fail to bring up a tunnel, you'll need to find out:</P>
+<UL>
+<LI><A HREF="#state">what your connection state is,</A> and often</LI>
+<LI><A HREF="#find.pluto.error">an error message</A>.</LI>
+</UL>
+<P>before you can<A HREF="#interpret.pluto.error"> diagnose your problem</A>
+.</P>
+<H3><A NAME="state"></A>2.1 Determine Connection State</H3>
+<H4>Finding current state</H4>
+<P>You can see connection states (STATE_MAIN_I1 and so on) when you
+ bring up a connection on the command line. If you have missed this, or
+ brought up your connection automatically, use:</P>
+<PRE>ipsec auto --status</PRE>
+<P>The most relevant state is the last one reached.</P>
+<H4><VAR>What's this supposed to look like?</VAR></H4>
+<P>Negotiations should proceed though various states, in the processes
+ of:</P>
+<OL>
+<LI>IKE negotiations (aka Phase 1, Main Mode, STATE_MAIN_*)</LI>
+<LI>IPSEC negotiations (aka Phase 2, Quick Mode, STATE_QUICK_*)</LI>
+</OL>
+<P>These are done and a connection is established when you see messages
+ like:</P>
+<PRE>    000 #21: &quot;myconn&quot; STATE_MAIN_I4 (ISAKMP SA established)...
+    000 #2: &quot;myconn&quot; STATE_QUICK_I2 (sent QI2, IPsec SA established)...</PRE>
+<P> Look for the key phrases are &quot;ISAKMP SA established&quot; and &quot;IPSec SA
+ established&quot;, with the relevant connection name. Often, this happens at
+ STATE_MAIN_I4 and STATE_QUICK_I2, respectively.</P>
+<P><VAR>ipsec auto --status</VAR> will tell you what states<STRONG> have
+ been achieved</STRONG>, rather than the current state. Since
+ determining the current state is rather more difficult to do, current
+ state information is not available from Linux FreeS/WAN. If you are
+ actively bringing a connection up, the status report's last states for
+ that connection likely reflect its current state. Beware, though, of
+ the case where a connection was correctly brought up but is now downed:
+ Linux FreeS/WAN will not notice this until it attempts to rekey.
+ Meanwhile, the last known state indicates that the connection has been
+ established.</P>
+<P>If your connection is stuck at STATE_MAIN_I1, skip straight to<A HREF="#ikepath">
+ here</A>.</P>
+<H3><A NAME="find.pluto.error"></A>2.2 Finding error text</H3>
+<P>Solving most errors will require you to find verbose error text,
+ either on the command line or in the logs.</P>
+<H4>Verbose start for more information</H4>
+<P> Note that you can get more detail from<VAR> ipsec auto</VAR> using
+ the --verbose flag:</P>
+<PRE STYLE="margin-bottom: 0.2in">    ipsec auto --verbose --up west-east</PRE>
+<P> More complete information can be gleaned from the<A HREF="#logusage">
+ log files</A>.</P>
+<H4>Debug levels count</H4>
+<P>The amount of description you'll get here depends on ipsec.conf debug
+ settings,<VAR> klipsdebug</VAR>= and<VAR> plutodebug</VAR>=. When
+ troubleshooting, set at least one of these to<VAR> all</VAR>, and when
+ done, reset it to<VAR> none</VAR> so your logs don't fill up. Note that
+ you must have enabled the<VAR> klipsdebug</VAR><A HREF="install.html#allbut">
+ compile-time option</A> for the<VAR> klipsdebug</VAR> configuration
+ switch to work.</P>
+<P>For negotiation problems<VAR> plutodebug</VAR> is most relevant.<VAR>
+ klipsdebug</VAR> applies mainly to attempts to use an
+ already-established connection. See also<A HREF="ipsec.html#parts">
+ this</A> description of the division of duties within Linux FreeS/WAN.</P>
+<P>After raising your debug levels, restart Linux FreeS/WAN to ensure
+ that ipsec.conf is reread, then recreate the error to generate verbose
+ logs.</P>
+<H4><VAR>ipsec barf</VAR> for lots of debugging information</H4>
+<P><A HREF="manpage.d/ipsec_barf.8.html"><VAR> ipsec barf (8)</VAR></A>
+ collects a bunch of useful debugging information, including these logs
+ Use the command</P>
+<PRE>
+    ipsec barf &gt; barf.west
+</PRE>
+<P>to generate one.</P>
+<H4>Find the error</H4>
+<P>Search out the failure point in your logs. Are there a handful of
+ lines which succinctly describe how things are going wrong or contrary
+ to your expectation? Sometimes the failure point is not immediately
+ obvious: Linux FreeS/WAN's errors are usually not marked &quot;Error&quot;. Have
+ a look in the<A HREF="faq.html"> FAQ</A> for what some common failures
+ look like.</P>
+<P>Tip: problems snowball. Focus your efforts on the first problem,
+ which is likely to be the cause of later errors.</P>
+<H4>Play both sides</H4>
+<P>Also find error text on the peer IPSec box. This gives you two
+ perspectives on the same failure.</P>
+<P>At times you will require information which only one side has. The
+ peer can merely indicate the presence of an error, and its approximate
+ point in the negotiations. If one side keeps retrying, it may be
+ because there is a show stopper on the other side. Have a look at the
+ other side and figure out what it doesn't like.</P>
+<P>If the other end is not Linux FreeS/WAN, the principle is the same:
+ replicate the error with its most verbose logging on, and capture the
+ output to a file.</P>
+<H3><A NAME="interpret.pluto.error"></A>2.3 Interpreting a Negotiation
+ Error</H3>
+<H4><A NAME="ikepath"></A>Connection stuck at STATE_MAIN_I1</H4>
+<P>This error commonly happens because IKE (port 500) packets, needed to
+ negotiate an IPSec connection, cannot travel freely between your IPSec
+ gateways. See<A HREF="firewall.html#packets"> our firewall document</A>
+ for details.</P>
+<H4>Other errors</H4>
+<P>Other errors require a bit more digging. Use the following resources:</P>
+<UL>
+<LI><A HREF="faq.html">the FAQ</A> . Since this document is constantly
+ updated, the snapshot's FAQ may have a new entry relevant to your
+ problem.</LI>
+<LI>our<A HREF="background.html"> background document</A> . Special
+ considerations which, while not central to Linux FreeS/WAN, are often
+ tripped over. Includes problems with<A href="background.html#MTU.trouble">
+ packet fragmentation</A>, and considerations for testing opportunism.</LI>
+<LI>the<A HREF="mail.html#lists"> list archives</A>. Each of the
+ searchable archives works differently, so it's worth checking each. Use
+ a search term which is generic, but identifies your error, for example
+ &quot;No connection is known for&quot;.
+<BR> Often, you will find that your question has been answered in the
+ past. Finding an archived answer is quicker than asking the list. You
+ may, however, find similar questions without answers. If you do, send
+ their URLs to the list with your trouble report. The additional
+ examples may help the list tech support person find your answer.</LI>
+<LI>Look into the code where the error is being generated. The pluto
+ code is nicely documented with comments and meaningful variable names.</LI>
+</UL>
+<P>If you have failed to solve your problem with the help of these
+ resources, send a detailed problem report to the users list, following
+ these<A HREF="#prob.report"> guidelines</A>.</P>
+<H2><A NAME="use"></A>3. Using a Connection</H2>
+<H3><A NAME="8_4_1">3.1 Orienting yourself</A></H3>
+<H4><VAR>How do I know if it works?</VAR></H4>
+<P>Test your connection by sending packets through it. The simplest way
+ to do this is with ping, but the ping needs to<STRONG> test the correct
+ tunnel.</STRONG> See<A HREF="#testgates"> this example scenario</A> if
+ you don't understand this.</P>
+<P></P>
+<P>If your ping returns, test any other connections you've brought u all
+ check out, great. You may wish to<A HREF="#bigpacket"> test with large
+ packets</A> for MTU problems.</P>
+<H4><VAR>ipsec barf</VAR> is useful again</H4>
+<P>If your ping fails to return, generate an ipsec barf debugging report
+ on each IPSec gateway. On a non-Linux FreeS/WAN implementation, gather
+ equivalent information. Use this, and the tips in the next sections, to
+ troubleshoot. Are you sure that both endpoints are capable of hearing
+ and responding to ping?</P>
+<H3><A NAME="8_4_2">3.2 Those pesky configuration errors</A></H3>
+<P>IPSec may be dropping your ping packets since they do not belong in
+ the tunnels you have constructed:</P>
+<UL>
+<LI>Your ping may not test the tunnel you intend to test. For details,
+ see our<A HREF="faq.html#cantping"> &quot;I can't ping&quot;</A> FAQ.</LI>
+<LI> Alternately, you may have a configuration error. For example, you
+ may have configured one of the four possible tunnels between two
+ gateways, but not the one required to secure the important traffic
+ you're now testing. In this case, add and start the tunnel, and try
+ again.</LI>
+</UL>
+<P>In either case, you will often see a message like:</P>
+<PRE>klipsdebug... no eroute</PRE>
+<P>which we discuss in<A HREF="faq.html#no_eroute"> this FAQ</A>.</P>
+<P>Note:</P>
+<UL>
+<LI><A HREF="glossary.html#NAT.gloss">Network Address Translation (NAT)</A>
+ and<A HREF="glossary.html#masq"> IP masquerade</A> may have an effect
+ on which tunnels you need to configure.</LI>
+<LI>When testing a tunnel that protects a multi-node subnet, try several
+ subnet nodes as ping targets, in case one node is routing incorrectly.</LI>
+</UL>
+<H3><A NAME="route.firewall"></A>3.3 Check Routing and Firewalling</H3>
+<P>If you've confirmed your configuration assumptions, the problem is
+ almost certainly with routing or firewalling. Isolate the problem using
+ interface statistics, firewall statistics, or a packet sniffer.</P>
+<H4>Background:</H4>
+<UL>
+<LI>Linux FreeS/WAN supplies all the special routing it needs; you need
+ only route packets out through your IPSec gateway. Verify that on the<VAR>
+ subnetted</VAR> machines you are using for your ping-test, your routing
+ is as expected. I have seen a tunnel &quot;fail&quot; because the subnet machine
+ sending packets out an alternate gateway (not our IPSec gateway) on
+ their return path.</LI>
+<LI>Linux FreeS/WAN requires particular<A HREF="firewall.html">
+ firewalling considerations</A>. Check the firewall rules on your IPSec
+ gateways and ensure that they allow IPSec traffic through. Be sure that
+ no other machine - for example a router between the gateways - is
+ blocking your IPSec packets.</LI>
+</UL>
+<H4><A NAME="ifconfig"></A>View Interface and Firewall Statistics</H4>
+<P>Interface reports and firewall statistics can help you track down
+ lost packets at a glance. Check any firewall statistics you may be
+ keeping on your IPSec gateways, for dropped packets.</P>
+<P><STRONG>Tip</STRONG>: You can take a snapshot of the packets
+ processed by your firewall with:</P>
+<PRE>    iptables -L -n -v</PRE>
+<P>You can get creative with &quot;diff&quot; to find out what happens to a
+ particular packet during transmission.</P>
+<P>Both<VAR> cat /proc/net/dev</VAR> and<VAR> ifconfig</VAR> display
+ interface statistics, and both are included in<VAR> ipsec barf</VAR>.
+ Use either to check if any interface has dropped packets. If you find
+ that one has, test whether this is related to your ping. While you ping
+ continuously, print that interface's statistics several times. Does its
+ drop count increase in proportion to the ping? If so, check why the
+ packets are dropped there.</P>
+<P>To do this, look at the firewall rules that apply to that interface.
+ If the interface is an IPSec interface, more information may be
+ available in the log. Grep for the word &quot;drop&quot; in a log which was
+ created with<VAR> klipsdebug=all</VAR> as the error happened.</P>
+<P>See also this<A HREF="#ifconfig1"> discussion</A> on interpreting<VAR>
+ ifconfig</VAR> statistics.</P>
+<H3><A NAME="sniff"></A>3.4 When in doubt, sniff it out</H3>
+<P>If you have checked configuration assumptions, routing, and firewall
+ rules, and your interface statistics yield no clue, it remains for you
+ to investigate the mystery of the lost packet by the most thorough
+ method: with a packet sniffer (providing, of course, that this is legal
+ where you are working).</P>
+<P>In order to detect packets on the ipsec virtual interfaces, you will
+ need an up-to-date sniffer (tcpdump, ethereal, ksnuffle) on your IPSec
+ gateway machines. You may also find it useful to sniff the ping
+ endpoints.</P>
+<H4>Anticipate your packets' path</H4>
+<P>Ping, and examine each interface along the projected path, checking
+ for your ping's arrival. If it doesn't get to the the next stop, you
+ have narrowed down where to look for it. In this way, you can isolate a
+ problem area, and narrow your troubleshooting focus.</P>
+<P>Within a machine running Linux FreeS/WAN, this<A HREF="firewall.html#packets">
+ packet flow diagram</A> will help you anticipate a packet's path.</P>
+<P>Note that:</P>
+<UL>
+<LI> from the perspective of the tunneled packet, the entire tunnel is
+ one hop. That's explained in<A HREF="faq.html#no_trace"> this</A> FAQ.</LI>
+<LI> an encapsulated IPSec packet will look different, when sniffed,
+ from the plaintext packet which generated it. You can see plaintext
+ packets entering an IPSec interface and the resulting cyphertext
+ packets as they emerge from the corresponding physical interface.</LI>
+</UL>
+<P>Once you isolate where the packet is lost, take a closer look at
+ firewall rules, routing and configuration assumptions as they affect
+ that specific area. If the packet is lost on an IPSec gateway, comb
+ through<VAR> klipsdebug</VAR> output for anomalies.</P>
+<P>If the packet goes through both gateways successfully and reaches the
+ ping target, but does not return, suspect routing. Check that the ping
+ target routes packets back to the IPSec gateway.</P>
+<H3><A NAME="find.use.error"></A>3.5 Check your logs</H3>
+<P>Here, too, log information can be useful. Start with the<A HREF="#find.pluto.error">
+ guidelines above</A>.</P>
+<P>For connection use problems, set<VAR> klipsdebug=all</VAR>. Note that
+ you must have enabled the<VAR> klipsdebug</VAR><A HREF="install.html#allbut">
+ compile-time option</A> to do this. Restart Linux FreeS/WAN so that it
+ rereads<VAR> ipsec.conf</VAR>, then recreate the error condition. When
+ searching through<VAR> klipsdebug</VAR> data, look especially for the
+ keywords &quot;drop&quot; (as in dropped packets) and &quot;error&quot;.</P>
+<P>Often the problem with connection use is not software error, but
+ rather that the software is behaving contrary to expectation.</P>
+<H4><A NAME="interpret.use.error"></A>Interpreting log text</H4>
+<P>To interpret the Linux FreeS/WAN log text you've found, use the same
+ resources as indicated for troubleshooting connection negotiation:<A HREF="faq.html">
+ the FAQ</A> , our<A HREF="background.html"> background document</A>,
+ and the<A HREF="mail.html#lists"> list archives</A>. Looking in the
+ KLIPS code is only for the very brave.</P>
+<P>If you are still stuck, send a<A HREF="#prob.report"> detailed
+ problem report</A> to the users' list.</P>
+<H3><A NAME="bigpacket"></A>3.6 More testing for the truly thorough</H3>
+<H4>Large Packets</H4>
+<P>If each of your connections passed the ping test, you may wish to
+ test by pinging with large packets (2000 bytes or larger). If it does
+ not return, suspect MTU issues, and see this<A HREF="background.html#MTU.trouble">
+ discussion</A>.</P>
+<H4>Stress Tests</H4>
+<P>In most users' view, a simple ping test, and perhaps a large-packet
+ ping test suffice to indicate a working IPSec connection.</P>
+<P>Some people might like to do additional stress tests prior to
+ production use. They may be interested in this<A HREF="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/12/msg00224.html">
+ testing protocol</A> we use at interoperation conferences, aka
+ &quot;bakeoffs&quot;. We also have a<VAR> testing</VAR> directory that ships with
+ the release.</P>
+<H2><A NAME="prob.report"></A>4. Problem Reporting</H2>
+<H3><A NAME="8_5_1">4.1 How to ask for help</A></H3>
+<P>Ask for troubleshooting help on the users' mailing list,<A HREF="mailto:users@lists.freeswan.org">
+ users@lists.freeswan.org</A>. While sometimes an initial query with a
+ quick description of your intent and error will twig someone's memory
+ of a similar problem, it's often necessary to send a second mail with a
+ complete problem report.</P>
+<P>When reporting problems to the mailing list(s), please include:</P>
+<UL>
+<LI>a brief description of the problem</LI>
+<LI>if it's a compile problem, the actual output from make, showing the
+ problem. Try to edit it down to only the relevant part, but when in
+ doubt, be as complete as you can. If it's a kernel compile problem, any
+ relevant out.* files</LI>
+<LI>if it's a run-time problem, pointers to where we can find the
+ complete output from &quot;ipsec barf&quot; from BOTH ENDS (not just one of
+ them). Remember that it's common outside the US and Canada to pay for
+ download volume, so if you can't post barfs on the web and send the URL
+ to the mailing list, at least compress them with tar or gzip.
+<BR> If you can, try to simplify the case that is causing the problem.
+ In particular, if you clear your logs, start FreeS/WAN with no other
+ connections running, cause the problem to happen, and then do<VAR>
+ ipsec barf</VAR> on both ends immediately, that gives the smallest and
+ least cluttered output.</LI>
+<LI>any other error messages, complaints, etc. that you saw. Please send
+ the complete text of the messages, not just a summary.</LI>
+<LI>what your network setup is. Include subnets, gateway addresses, etc.
+ A schematic diagram is a good format for this information.</LI>
+<LI>exactly what you were trying to do with Linux FreeS/WAN, and exactly
+ what went wrong</LI>
+<LI>a fix, if you have one. But remember, you are sending mail to people
+ all over the world; US residents and US citizens in particular, please
+ read doc/exportlaws.html before sending code -- even small bug fixes --
+ to the list or to us.</LI>
+<LI>When in doubt about whether to include some seemingly-trivial item
+ of information, include it. It is rare for problem reports to have too
+ much information, and common for them to have too little.</LI>
+</UL>
+<P>Here are some good general guidelines on bug reporting:<A href="http://tuxedo.org/~esr/faqs/smart-questions.html">
+ How To Ask Questions The Smart Way</A> and<A href="http://www.chiark.greenend.org.uk/~sgtatham/bugs.html">
+ How to Report Bugs Effectively</A>.</P>
+<H3><A NAME="8_5_2">4.2 Where to ask</A></H3>
+<P>To report a problem, send mail about it to the users' list. If you
+ are certain that you have found a bug, report it to the bugs list. If
+ you encounter a problem while doing your own coding on the Linux
+ FreeS/WAN codebase and think it is of interest to the design team,
+ notify the design list. When in doubt, default to the users' list. More
+ information about the mailing lists is found<A HREF="mail.html#lists">
+ here</A>.</P>
+<P>For a number of reasons -- including export-control regulations
+ affecting almost any<STRONG> private</STRONG> discussion of encryption
+ software -- we prefer that problem reports and discussions go to the
+ lists, not directly to the team. Beware that the list goes worldwide;
+ US citizens, read this important information about your<A HREF="politics.html#exlaw">
+ export laws</A>. If you're using this software, you really should be on
+ the lists. To get onto them, visit<A HREF="http://lists.freeswan.org/">
+ lists.freeswan.org</A>.</P>
+<P>If you do send private mail to our coders or want a private reply
+ from them, please make sure that the return address on your mail (From
+ or Reply-To header) is a valid one. They have more important things to
+ do than to unravel addresses that have been mangled in an attempt to
+ confuse spammers.</P>
+<H2><A NAME="notes"></A>5. Additional Notes on Troubleshooting</H2>
+<P>The following sections supplement the Guide:<A HREF="#system.info">
+ information available on your system</A>;<A HREF="#testgates"> testing
+ between security gateways</A>;<A HREF="#ifconfig1"> ifconfig reports
+ for KLIPS debugging</A>;<A HREF="#gdb"> using GDB on Pluto</A>.</P>
+<H3><A NAME="system.info"></A>5.1 Information available on your system</H3>
+<H4><A NAME="logusage"></A>Logs used</H4>
+<P>Linux FreeS/WAN logs to:</P>
+<UL>
+<LI>/var/log/secure (or, on Debian, /var/log/auth.log)</LI>
+<LI>/var/log/messages</LI>
+</UL>
+<P>Check both places to get full information. If you find nothing, check
+ your<VAR> syslogd.conf(5)</VAR> to see where your /etc/syslog.conf or
+ equivalent is directing<VAR> authpriv</VAR> messages.</P>
+<H4><A NAME="pages"></A>man pages provided</H4>
+<DL>
+<DT><A HREF="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</A></DT>
+<DD> Manual page for IPSEC configuration file.</DD>
+<DT><A HREF="manpage.d/ipsec.8.html"> ipsec(8)</A></DT>
+<DD STYLE="margin-bottom: 0.2in"> Primary man page for ipsec utilities.</DD>
+</DL>
+<P> Other man pages are on<A HREF="manpages.html"> this list</A> and in</P>
+<UL>
+<LI>/usr/local/man/man3</LI>
+<LI>/usr/local/man/man5</LI>
+<LI>/usr/local/man/man8/ipsec_*</LI>
+</UL>
+<H4><A NAME="statusinfo"></A>Status information</H4>
+<DL>
+<DT>ipsec auto --status</DT>
+<DD> Command to get status report from running system. Displays Pluto's
+ state. Includes the list of connections which are currently &quot;added&quot; to
+ Pluto's internal database; lists state objects reflecting ISAKMP and
+ IPsec SAs being negotiated or installed.</DD>
+<DT> ipsec look</DT>
+<DD> Brief status info.</DD>
+<DT> ipsec barf</DT>
+<DD STYLE="margin-bottom: 0.2in"> Copious debugging info.</DD>
+</DL>
+<H3><A NAME="testgates"></A> 5.2 Testing between security gateways</H3>
+<P>Sometimes you need to test a subnet-subnet tunnel. This is a tunnel
+ between two security gateways, which protects traffic on behalf of the
+ subnets behind these gateways. On this network:</P>
+<PRE>     Sunset==========West------------------East=========Sunrise
+                     IPSec gateway         IPSec gateway
+           local net       untrusted net       local net</PRE>
+<P> you might name this tunnel sunset-sunrise. You can test this tunnel
+ by having a machine behind one gateway ping a machine behind the other
+ gateway, but this is not always convenient or even possible.</P>
+<P>Simply pinging one gateway from the other is not useful. Such a ping
+ does not normally go through the tunnel.<STRONG> The tunnel handles
+ traffic between the two protected subnets, not between the gateways</STRONG>
+ . Depending on the routing in place, a ping might</P>
+<UL>
+<LI>either succeed by finding an unencrypted route</LI>
+<LI>or fail by finding no route. Packets without an IPSEC eroute are
+ discarded.</LI>
+</UL>
+<P><STRONG>Neither event tells you anything about the tunnel</STRONG>.
+ You can explicitly create an eroute to force such packets through the
+ tunnel, or you can create additional tunnels as described in our<A HREF="config.html#multitunnel">
+ configuration document</A>, but those may be unnecessary complications
+ in your situation.</P>
+<P>The trick is to explicitly test between<STRONG> both gateways'
+ private-side IP addresses</STRONG>. Since the private-side interfaces
+ are on the protected subnets, the resulting packets do go via the
+ tunnel. Use either ping -I or traceroute -i, both of which allow you to
+ specify a source interface. (Note: unsupported on older Linuxes). The
+ same principles apply for a road warrior (or other) case where only one
+ end of your tunnel is a subnet.</P>
+<H3><A NAME="ifconfig1"></A>5.3 ifconfig reports for KLIPS debugging</H3>
+<P>When diagnosing problems using ifconfig statistics, you may wonder
+ what type of activity increments a particular counter for an ipsecN
+ device. Here's an index, posted by KLIPS developer Richard Guy Briggs:</P>
+<PRE>Here is a catalogue of the types of errors that can occur for which
+statistics are kept when transmitting and receiving packets via klips.
+I notice that they are not necessarily logged in the right counter.
+. . .
+
+Sources of ifconfig statistics for ipsec devices
+
+rx-errors:
+- packet handed to ipsec_rcv that is not an ipsec packet.
+- ipsec packet with payload length not modulo 4.
+- ipsec packet with bad authenticator length.
+- incoming packet with no SA.
+- replayed packet.
+- incoming authentication failed.
+- got esp packet with length not modulo 8.
+
+tx_dropped:
+- cannot process ip_options.
+- packet ttl expired.
+- packet with no eroute.
+- eroute with no SA.
+- cannot allocate sk_buff.
+- cannot allocate kernel memory.
+- sk_buff internal error.
+
+
+The standard counters are:
+
+struct enet_statistics
+{
+        int        rx_packets;                /* total packets received */
+        int        tx_packets;                /* total packets transmitted */
+        int        rx_errors;                /* bad packets received */
+        int        tx_errors;                /* packet transmit problems */
+        int        rx_dropped;                /* no space in linux buffers */
+        int        tx_dropped;                /* no space available in linux */
+        int        multicast;                /* multicast packets received */
+        int        collisions;
+
+        /* detailed rx_errors: */
+        int        rx_length_errors;
+        int        rx_over_errors;                /* receiver ring buff overflow */
+        int        rx_crc_errors;                /* recved pkt with crc error */
+        int        rx_frame_errors;        /* recv'd frame alignment error */
+        int        rx_fifo_errors;                /* recv'r fifo overrun */
+        int        rx_missed_errors;        /* receiver missed packet */
+
+        /* detailed tx_errors */
+        int        tx_aborted_errors;
+        int        tx_carrier_errors;
+        int        tx_fifo_errors;
+        int        tx_heartbeat_errors;
+        int        tx_window_errors;
+};
+
+of which I think only the first 6 are useful.</PRE>
+<H3><A NAME="gdb"></A> 5.4 Using GDB on Pluto</H3>
+<P>You may need to use the GNU debugger, gdb(1), on Pluto. This should
+ be necessary only in unusual cases, for example if you encounter a
+ problem which the Pluto developer cannot readily reproduce or if you
+ are modifying Pluto.</P>
+<P>Here are the Pluto developer's suggestions for doing this:</P>
+<PRE>Can you get a core dump and use gdb to find out what Pluto was doing
+when it died?
+
+To get a core dump, you will have to set dumpdir to point to a
+suitable directory (see <A HREF="manpage.d/ipsec.conf.5.html">ipsec.conf(5)</A>).
+
+To get gdb to tell you interesting stuff:
+        $ script
+        $ cd dump-directory-you-chose
+        $ gdb /usr/local/lib/ipsec/pluto core
+        (gdb) where
+        (gdb) quit
+        $ exit
+
+The resulting output will have been captured by the script command in
+a file called &quot;typescript&quot;.  Send it to the list.
+
+Do not delete the core file.  I may need to ask you to print out some
+more relevant stuff.</PRE>
+<P> Note that the<VAR> dumpdir</VAR> parameter takes effect only when
+ the IPsec subsystem is restarted -- reboot or ipsec setup restart.</P>
+<P>
+<BR>
+<BR></P>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="firewall.html">Previous</A>
+<A HREF="compat.html">Next</A>
+</BODY>
+</HTML>
diff --git a/doc/umltesting.html b/doc/umltesting.html
new file mode 100644
index 000000000..35bcef96d
--- /dev/null
+++ b/doc/umltesting.html
@@ -0,0 +1,313 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
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+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="roadmap.html">Previous</A>
+<A HREF="makecheck.html">Next</A>
+<HR>
+<H1><A name="umltesting">User-Mode-Linux Testing guide</A></H1>
+<P> User mode linux is a way to compile a linux kernel such that it can
+ run as a process in another linux system (potentially as a *BSD or
+ Windows process later). See<A HREF="http://user-mode-linux.sourceforge.net/">
+ http://user-mode-linux.sourceforge.net/</A></P>
+<P> UML is a good platform for testing and experimenting with FreeS/WAN.
+ It allows several network nodes to be simulated on a single machine.
+ Creating, configuring, installing, monitoring, and controling these
+ nodes is generally easier and easier to script with UML than real
+ hardware.</P>
+<P> You'll need about 500Mb of disk space for a full
+ sunrise-east-west-sunset setup. You can possibly get this down by 130Mb
+ if you remove the sunrise/sunset kernel build. If you just want to run,
+ then you can even remove the east/west kernel build.</P>
+<P> Nothing need be done as super user. In a couple of steps, we note
+ where super user is required to install commands in system-wide
+ directories, but ~/bin could be used instead. UML seems to use a
+ system-wide /tmp/uml directory so different users may interfere with
+ one another. Later UMLs use ~/.uml instead, so multiple users running
+ UML tests should not be a problem, but note that a single user running
+ the UML tests will only be able run one set. Further, UMLs sometimes
+ get stuck and hang around. These &quot;zombies&quot; (most will actually be in
+ the &quot;T&quot; state in the process table) will interfere with subsequent
+ tests.</P>
+<H2><A NAME="34_1">Preliminary Notes on BIND</A></H2>
+<P> As of 2003/3/1, the Light-Weight Resolver is used by pluto. This
+ requires that BIND9 be running. It also requires that BIND9 development
+ libraries be present in the build environment. The DNSSEC code is only
+ truly functional in BIND9 snapshots. The library code could be 9.2.2,
+ we believe. We are using BIND9 20021115 snapshot code from<A HREF="ftp://ftp.isc.org/isc/bind9/snapshots">
+ ftp://ftp.isc.org/isc/bind9/snapshots</A>.</P>
+<P> FreeS/WAN may well require a newer BIND than is on your system. Many
+ distributions have moved to BIND9.2.2 recently due to a security
+ advisory. BIND is five components.</P>
+<OL>
+<LI> named</LI>
+<LI> dnssec-*</LI>
+<LI> client side resolver libraries</LI>
+<LI> client side utility libraries I thought there were lib and named
+ parts to dnsssec...</LI>
+<LI> dynamic DNS update utilities</LI>
+</OL>
+<P> The only piece that we need for *building* is #4. That's the only
+ part that has to be on the build host. What is the difference between
+ resolver and util libs? If you want to edit
+ testing/baseconfigs/all/etc/bind, you'll need a snapshot version. The
+ resolver library contains the resolver. FreeS/WAN has its own copy of
+ that in lib/liblwres.</P>
+<H2><A NAME="34_2">Steps to Install UML for FreeS/WAN</A></H2>
+<OL>
+<LI> Get the following files:
+<OL type="a">
+<LI> from<A HREF="http://www.sandelman.ottawa.on.ca/freeswan/uml/">
+ http://www.sandelman.ottawa.on.ca/freeswan/uml/</A>
+ umlfreeroot-15.1.tar.gz (or highest numbered one). This is a debian
+ potato root file system. You can use this even on a Redhat host, as it
+ has the newer GLIBC2.2 libraries as well.
+<!-- If you are using
+  Redhat 7.2 or newer as your development machine, you can create the
+  image from your installation media. See <A HREF="uml-rhroot.html">Building a RedHat root"></A>.
+  A future document will explain how to build this from .DEB files as well.
+-->
+
+<!--
+<LI> umlfreesharemini.tar.gz    (or umlfreeshareall.tar.gz). 
+  If you are a Debian potato user, you don't need it you can use your
+  native /usr/share.
+</UL>
+-->
+</LI>
+<LI> From<A HREF="ftp://ftp.xs4all.nl/pub/crypto/freeswan/">
+ ftp://ftp.xs4all.nl/pub/crypto/freeswan/</A> a snapshot or release
+ (1.92 or better)</LI>
+<LI> From a<A HREF="http://www.kernel.org/mirrors/">
+ http://www.kernel.org mirror</A>, the virgin 2.4.19 kernel. Please
+ realize that we have defaults in our tree for kernel configuration. We
+ try to track the latest UML kernels. If you use a newer kernel, you may
+ have faults in the kernel build process. You can see what the latest
+ that is being regularly tested by visiting<A HREF="http://bugs.freeswan.org:81/regress/HEAD/lastgood/freeswan-regress-env.sh">
+ freeswan-regress-env.sh</A>.</LI>
+<LI>
+<!-- Note: this step is refered to as "step 1d" below. -->
+ Get<A HREF="http://ftp.nl.linux.org/uml/">
+ http://ftp.nl.linux.org/uml/</A> uml-patch-2.4.19-47.bz2 or the one
+ associated with your kernel. As of 2003/03/05, uml-patch-2.4.19-47.bz2
+ works for us.<STRONG> More recent versions of the patch have not been
+ tested by us.</STRONG></LI>
+<LI> You'll probably want to visit<A HREF="http://user-mode-linux.sourceforge.net">
+ http://user-mode-linux.sourceforge.net</A> and get the UML utilities.
+ These are not needed for the build or interactive use (but
+ recommended). They are necessary for the regression testing procedures
+ used by &quot;make check&quot;. We currently use uml_utilities_20020212.tar.bz2.</LI>
+<LI> You need tcpdump version 3.7.1 or better. This is newer than the
+ version included in most LINUX distributions. You can check the version
+ of an installed tcpdump with the --version flag. If you need a newer
+ tcpdump fetch both tcpdump and libpcap source tar files from<A HREF="http://www.tcpdump.org/">
+ http://www.tcpdump.org/</A> or a mirror.</LI>
+</OL>
+</LI>
+<LI> Pick a suitable place, and extract the following files:
+<OL type="a">
+<LI>
+<!-- Note: this step is refered to as "step 2a" later. -->
+ 2.4.19 kernel. For instance:
+<PRE>
+ <CODE>           cd /c2/kernel
+           tar xzvf ../download/pub/linux/kernel/v2.4/linux-2.4.19.tar.gz
+</CODE>
+</PRE>
+</LI>
+<LI> extract the umlfreeroot file
+<!-- (unless you <A HREF="uml-rhroot.html">built your own from RPMs</A>) -->
+
+<PRE>
+ <CODE>           mkdir -p /c2/user-mode-linux/basic-root
+           cd /c2/user-mode-linux/basic-root
+           tar xzvf ../download/umlfreeroot-15.1.tar.gz
+</CODE>
+</PRE>
+</LI>
+<LI> FreeSWAN itself (or checkout &quot;all&quot; from CVS)
+<PRE>
+ <CODE>           mkdir -p /c2/freeswan/sandbox
+           cd /c2/freeswan/sandbox
+           tar xzvf ../download/snapshot.tar.gz
+</CODE>
+</PRE>
+</LI>
+</OL>
+</LI>
+<LI> If you need to build a newer tcpdump:
+<UL>
+<LI> Make sure you have OpenSSL installed -- it is needed for
+ cryptographic routines.</LI>
+<LI> Unpack libpcap and tcpdump source in parallel directories (the
+ tcpdump build procedures look for libpcap next door).</LI>
+<LI> Change directory into the libpcap source directory and then build
+ the library:
+<PRE>
+ <CODE>	./configure
+	make
+</CODE>
+</PRE>
+</LI>
+<LI> Change into the tcpdump source directory, build tcpdump, and
+ install it.
+<PRE>
+ <CODE>	./configure
+	make
+	# Need to be superuser to install in system directories.
+	# Installing in ~/bin would be an alternative.
+	su -c &quot;make install&quot;
+</CODE>
+</PRE>
+</LI>
+</UL>
+</LI>
+<LI> If you need the uml utilities, unpack them somewhere then build and
+ install them:
+<PRE>
+ <CODE>	cd tools
+	make all
+	# Need to be superuser to install in system directories.
+	# Installing in ~/bin would be an alternative.
+	su -c &quot;make install BIN_DIR=/usr/local/bin&quot;
+</CODE>
+</PRE>
+</LI>
+<LI> set up the configuration file
+<UL>
+<LI> <CODE>cd /c2/freeswan/sandbox/freeswan-1.97/testing/utils</CODE></LI>
+<LI> copy umlsetup-sample.sh to ../../umlsetup.sh: <CODE> cp
+ umlsetup-sample.sh ../../umlsetup.sh</CODE></LI>
+<LI> open up ../../umlsetup.sh in your favorite editor.</LI>
+<LI> change POOLSPACE= to point to the place with at least 500Mb of
+ disk. Best if it is on the same partition as the &quot;umlfreeroot&quot;
+ extraction, as it will attempt to use hard links if possible to save
+ disk space.</LI>
+<LI> Set TESTINGROOT if you intend to run the script outside of the
+ sandbox/snapshot/release directory. Otherwise, it will configure
+ itself.</LI>
+<LI> KERNPOOL should point to the directory with your 2.4.19 kernel
+ tree. This tree should be unconfigured! This is the directory you used
+ in step 2a.</LI>
+<LI> UMLPATCH should point at the bz2 file you downloaded at 1d. If
+ using a kernel that already includes the patch, set this to /dev/null.</LI>
+<LI> FREESWANDIR should point at the directory where you unpacked the
+ snapshot/release. Include the &quot;freeswan-snap2001sep16b&quot; or whatever in
+ it. If you are running from CVS, then you point at the directory where
+ top, klips, etc. are. The script will fix up the directory so that it
+ can be used.</LI>
+<LI> BASICROOT should be set to the directory used in 2b, or to the
+ directory that you created with RPMs.</LI>
+<LI> SHAREDIR should be set to the directory used in 2c, to /usr/share
+ for Debian potato users, or to $BASICROOT/usr/share.</LI>
+</UL>
+</LI>
+<LI>
+<PRE> <CODE>cd $TESTINGROOT/utils
+sh make-uml.sh
+</CODE></PRE>
+ It will grind for awhile. If there are errors it will bail. If so, run
+ it under &quot;script&quot; and send the output to bugs@lists.freeswan.org.</LI>
+<LI> You will have a bunch of stuff under $POOLSPACE. Open four xterms:
+<PRE> <CODE>    for i in sunrise sunset east west
+    do
+        xterm -name $i -title $i -e $POOLSPACE/$i/start.sh     done
+</CODE></PRE>
+</LI>
+<LI> Login as root. Password is &quot;root&quot; (Note, these virtual machines are
+ networked together, but are not configured to talk to the rest of the
+ world.)</LI>
+<LI> verify that pluto started on east/west, run &quot;ipsec look&quot;</LI>
+<LI> login to sunrise. run &quot;ping sunset&quot;</LI>
+<LI> login to west. run &quot;tcpdump -p -i eth1 -n&quot; (tcpdump must be version
+ 3.7.1 or newer)</LI>
+<LI> Closing a console xterm will shut down that UML.</LI>
+<LI> You can &quot;make check&quot;, if you want to. It is run from
+ /c2/freeswan/sandbox/freeswan-1.97.</LI>
+</OL>
+<H1><A NAME="35">Debugging the kernel with GDB</A></H1>
+<P> With User-Mode-Linux, you can debug the kernel using GDB. See
+<!--HREF="http://user-mode-linux.sourceforge.net/debugging.html"-->
+
+ http://user-mode-linux.sourceforge.net/debugging.html.</(null)></P>
+<P> Typically, one will want to address a test case for a failing
+ situation. Running GDB from Emacs, or from other front ends is
+ possible. First start GDB.</P>
+<P> Tell it to open the UMLPOOL/swan/linux program.</P>
+<P> Note the PID of GDB:</P>
+<PRE>
+marajade-[projects/freeswan/mgmt/planning] mcr 1029 %ps ax | grep gdb
+ 1659 pts/9    SN     0:00 /usr/bin/gdb -fullname -cd /mara4/freeswan/kernpatch/UMLPOOL/swan/ linux
+</PRE>
+<P> Set the following in the environment:</P>
+<PRE>
+UML_east_OPT=&quot;debug gdb-pid=1659&quot;
+</PRE>
+<P> Then start the user-mode-linux in the test scheme you wish:</P>
+<PRE>
+marajade-[kernpatch/testing/klips/east-icmp-02] mcr 1220 %../../utils/runme.sh
+</PRE>
+ The user-mode-linux will stop on boot, giving you a chance to attach to
+ the process:
+<PRE>
+(gdb) file linux
+Reading symbols from linux...done.
+(gdb) attach 1
+Attaching to program: /mara4/freeswan/kernpatch/UMLPOOL/swan/linux, process 1
+0xa0118bc1 in kill () at hostfs_kern.c:770
+</PRE>
+<P> At this point, break points should be created as appropriate.</P>
+<H2><A NAME="35_1">Other notes about debugging</A></H2>
+<P> If you are running a standard test, after all the packets are sent,
+ the UML will be shutdown. This can cause problems, because the UML may
+ get terminated while you are debugging.</P>
+<P> The environment variable <CODE>NETJIGWAITUSER</CODE> can be set to
+ &quot;waituser&quot;. If so, then the testing system will prompt before exiting
+ the test.</P>
+<H1><A NAME="36">User-Mode-Linux mysteries</A></H1>
+<UL>
+<LI> running more than one UML of the same name (e.g. &quot;west&quot;) can cause
+ problems.</LI>
+<LI> running more than one UML from the same root file system is not a
+ good idea.</LI>
+<LI> all this means that running &quot;make check&quot; twice on the same machine
+ is probably not a good idea.</LI>
+<LI> occationally, UMLs will get stuck. This can happen like:
+<!--BLOCK-->
+ 15134 ? T
+ 0:00 /spare/hugh/uml/uml2.4.18-sept5/umlbuild/east/linux (east)
+ [/bin/sh] 15138 ? T 0:00
+ /spare/hugh/uml/uml2.4.18-sept5/umlbuild/east/linux (east) [halt]</(null)>
+ these will need to be killed. Note that they are in &quot;T&quot;racing mode.</LI>
+<LI> UMLs can also hang, and will report &quot;Tracing myself and I can't get
+ out&quot;. This is a bug in UML. There are ways to find out what is going on
+ and report this to the UML people, but we don't know the magic right
+ now.</LI>
+</UL>
+<H1><A NAME="37">Getting more info from uml_netjig</A></H1>
+<P> uml_netjig can be compiled with a built-in tcpdump. This uses
+ not-yet-released code from<A HREF="http://www.tcpdump.org/">
+ www.tcpdump.org</A>. Please see the instructions in <CODE>
+testing/utils/uml_netjig/Makefile</CODE>.</P>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="roadmap.html">Previous</A>
+<A HREF="makecheck.html">Next</A>
+</BODY>
+</HTML>
diff --git a/doc/upgrading.html b/doc/upgrading.html
new file mode 100644
index 000000000..ce9fba3d2
--- /dev/null
+++ b/doc/upgrading.html
@@ -0,0 +1,184 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
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+PRE { font-family: monospace }
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+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="intro.html">Previous</A>
+<A HREF="quickstart.html">Next</A>
+<HR>
+<A NAME="upgrading"></A>
+<H1><A NAME="2">Upgrading to FreeS/WAN 2.x</A></H1>
+<H2><A NAME="2_1">New! Built in Opportunistic connections</A></H2>
+<P>Out of the box, FreeS/WAN 2.x will attempt to encrypt all your IP
+ traffic. It will try to establish IPsec connections for:</P>
+<UL>
+<LI> IP traffic from the Linux box on which you have installed
+ FreeS/WAN, and</LI>
+<LI> outbound IP traffic routed through that Linux box (eg. from a
+ protected subnet).</LI>
+</UL>
+<P>FreeS/WAN 2.x uses<STRONG> hidden, automatically enabled<VAR>
+ ipsec.conf</VAR> connections</STRONG> to do this.</P>
+<P>This behaviour is part of our campaign to get Opportunistic
+ Encryption (OE) widespread in the Linux world, so that any two Linux
+ boxes can encrypt to one another without prearrangement. There's one
+ catch, however: you must<A HREF="quickstart.html#quickstart"> set up a
+ few DNS records</A> to distribute RSA public keys and (if applicable)
+ IPsec gateway information.</P>
+<P>If you start FreeS/WAN before you have set up these DNS records, your
+ connectivity will be slow, and messages relating to the built in
+ connections will clutter your logs. If you are unable to set up DNS for
+ OE, you will wish to<A HREF="policygroups.html#disable_policygroups">
+ disable the hidden connections</A>.</P>
+<A NAME="upgrading.flagday"></A>
+<H3><A NAME="2_1_1">Upgrading Opportunistic Encryption to 2.01 (or
+ later)</A></H3>
+<P>As of FreeS/WAN 2.01, Opportunistic Encryption (OE) uses DNS TXT
+ resource records (RRs) only (rather than TXT with KEY). This change
+ causes a &quot;flag day&quot;. Users of FreeS/WAN 2.00 (or earlier) OE who are
+ upgrading may need to post additional resource records.</P>
+<P>If you are running<A HREF="glossary.html#initiate-only">
+ initiate-only OE</A>, you<EM> must</EM> put up a TXT record in any
+ forward domain as per our<A HREF="quickstart.html#opp.client">
+ quickstart instructions</A>. This replaces your old forward KEY.</P>
+<P> If you are running full OE, you require no updates. You already have
+ the needed TXT record in the reverse domain. However, to facilitate
+ future features, you may also wish to publish that TXT record in a
+ forward domain as instructed<A HREF="quickstart.html#opp.incoming">
+ here</A>.</P>
+<P>If you are running OE on a gateway (and encrypting on behalf of
+ subnetted boxes) you require no updates. You already have the required
+ TXT record in your gateway's reverse map, and the TXT records for any
+ subnetted boxes require no updating. However, to facilitate future
+ features, you may wish to publish your gateway's TXT record in a
+ forward domain as shown<A HREF="quickstart.html#opp.incoming"> here</A>
+.</P>
+<P> During the transition, you may wish to leave any old KEY records up
+ for some time. They will provide limited backward compatibility.
+<!--
+For more
+detail on that compatibility, see <A HREF="oe.known-issues">Known Issues with
+OE</A>.
+-->
+</P>
+<H2><A NAME="2_2">New! Policy Groups</A></H2>
+<P>We want to make it easy for you to declare security policy as it
+ applies to IPsec connections.</P>
+<P>Policy Groups make it simple to say:</P>
+<UL>
+<LI>These are the folks I want to talk to in the clear.</LI>
+<LI>These spammers' domains -- I don't want to talk to them at all.</LI>
+<LI>To talk to the finance department, I must use IPsec.</LI>
+<LI>For any other communication, try to encrypt, but it's okay if we
+ can't.</LI>
+</UL>
+<P>FreeS/WAN then implements these policies, creating OE connections if
+ and when needed. You can use Policy Groups along with connections you
+ explicitly define in ipsec.conf.</P>
+<P>For more information, see our<A HREF="policygroups.html"> Policy
+ Group HOWTO</A>.</P>
+<H2><A NAME="2_3">New! Packetdefault Connection</A></H2>
+<P>Free/SWAN 2.x ships with the<STRONG> automatically enabled, hidden
+ connection</STRONG><VAR> packetdefault</VAR>. This configures a
+ FreeS/WAN box as an OE gateway for any hosts located behind it. As
+ mentioned above, you must configure some<A HREF="quickstart.html"> DNS
+ records</A> for OE to work.</P>
+<P>As the name implies, this connection functions as a default. If you
+ have more specific connections, such as policy groups which configure
+ your FreeS/WAN box as an OE gateway for a local subnet, these will
+ apply before<VAR> packetdefault</VAR>. You can view<VAR> packetdefault</VAR>
+'s specifics in<A HREF="manpage.d/ipsec.conf.5.html"> man ipsec.conf</A>
+.</P>
+<H2><A NAME="2_4">FreeS/WAN now disables Reverse Path Filtering</A></H2>
+<P>FreeS/WAN often doesn't work with reverse path filtering. At start
+ time, FreeS/WAN now turns rp_filter off, and logs a warning.</P>
+<P>FreeS/WAN does not turn it back on again. You can do this yourself
+ with a command like:</P>
+<PRE>   echo 1 &gt; /proc/sys/net/ipv4/conf/eth0/rp_filter</PRE>
+<P>For eth0, substitute the interface which FreeS/WAN was affecting.</P>
+<A NAME="ipsec.conf_v2"></A>
+<H2><A NAME="2_5">Revised<VAR> ipsec.conf</VAR></A></H2>
+<H3><A NAME="2_5_1">No promise of compatibility</A></H3>
+<P>The FreeS/WAN team promised config-file compatibility throughout the
+ 1.x series. That means a 1.5 config file can be directly imported into
+ a fresh 1.99 install with no problems.</P>
+<P>With FreeS/WAN 2.x, we've given ourselves permission to make the
+ config file easier to use. The cost: some FreeS/WAN 1.x configurations
+ will not work properly. Many of the new features are, however, backward
+ compatible.</P>
+<H3><A NAME="2_5_2">Most<VAR> ipsec.conf</VAR> files will work fine</A></H3>
+<P>... so long as you paste this line,<STRONG> with no preceding
+ whitespace</STRONG>, at the top of your config file:</P>
+<PRE>    version 2</PRE>
+<H3><A NAME="2_5_3">Backward compatibility patch</A></H3>
+<P>If the new defaults bite you, use<A HREF="ipsec.conf.2_to_1"> this<VAR>
+ ipsec.conf</VAR> fragment</A> to simulate the old default values.</P>
+<H3><A NAME="2_5_4">Details</A></H3>
+<P> We've obsoleted various directives which almost no one was using:</P>
+<PRE>    dump
+    plutobackgroundload
+    no_eroute_pass
+    lifetime
+    rekeystart
+    rekeytries</PRE>
+<P>For most of these, there is some other way to elicit the desired
+ behaviour. See<A HREF="http://lists.freeswan.org/pipermail/design/2002-August/003243.html">
+ this post</A>.</P>
+<P> We've made some settings, which almost everyone was using, defaults.
+ For example:</P>
+<PRE>    interfaces=%defaultroute
+    plutoload=%search
+    plutostart=%search
+    uniqueids=yes</PRE>
+<P>We've also changed some default values to help with OE and Policy
+ Groups:</P>
+<PRE>    authby=rsasig   ## not secret!!!
+    leftrsasigkey=%dnsondemand ## looks up missing keys in DNS when needed.
+    rightrsasigkey=%dnsondemand</PRE>
+<P> Of course, you can still override any defaults by explictly
+ declaring something else in your connection.</P>
+<P><A HREF="http://lists.freeswan.org/pipermail/design/2002-August/003243.html">
+ A post with a list of many ipsec.conf changes.</A>
+<BR><A HREF="manpage.d/ipsec.conf.5.html"> Current ipsec.conf manual.</A>
+</P>
+<A NAME="upgrading.rpms"></A>
+<H3><A NAME="2_5_5">Upgrading from 1.x RPMs to 2.x RPMs</A></H3>
+<P>Note: When upgrading from 1-series to 2-series RPMs,<VAR> rpm -U</VAR>
+ will not work.</P>
+<P>You must instead erase the 1.x RPMs, then install the 2.x set:</P>
+<PRE>    rpm -e freeswan</PRE>
+<PRE>    rpm -e freeswan-module</PRE>
+<P>On erasing, your old<VAR> ipsec.conf</VAR> should be moved to<VAR>
+ ipsec.conf.rpmsave</VAR>. Keep this. You will probably want to copy
+ your existing connections to the end of your new 2.x file.</P>
+<P>Install the RPMs suitable for your kernel version, such as:</P>
+<PRE>    rpm -ivh freeswan-module-2.04_2.4.20_20.9-0.i386.rpm</PRE>
+<PRE>    rpm -ivh freeswan-userland-2.04_2.4.20_20.9-0.i386.rpm</PRE>
+<P>Or, to splice the files:</P>
+<PRE>    cat /etc/ipsec.conf /etc/ipsec.conf.rpmsave &gt; /etc/ipsec.conf.tmp
+    mv /etc/ipsec.conf.tmp /etc/ipsec.conf</PRE>
+<P>Then, remove the redundant<VAR> conn %default</VAR> and<VAR> config
+ setup</VAR> sections. Unless you have done any special configuring
+ here, you'll likely want to remove the 1.x versions. Remove<VAR> conn
+ OEself</VAR>, if present.</P>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="intro.html">Previous</A>
+<A HREF="quickstart.html">Next</A>
+</BODY>
+</HTML>
diff --git a/doc/user_examples.html b/doc/user_examples.html
new file mode 100644
index 000000000..d683c92e1
--- /dev/null
+++ b/doc/user_examples.html
@@ -0,0 +1,320 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
+H5 { font-family: sans-serif }
+H6 { font-family: sans-serif }
+SUB { font-size: smaller }
+SUP { font-size: smaller }
+PRE { font-family: monospace }
+--></STYLE>
+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="background.html">Previous</A>
+<A HREF="makecheck.html">Next</A>
+<HR>
+<H1><A name="user.examples">FreeS/WAN script examples</A></H1>
+ This file is intended to hold a collection of user-written example
+ scripts or configuration files for use with FreeS/WAN.
+<P> So far it has only one entry.</P>
+<H2><A name="poltorak">Poltorak's Firewall script</A></H2>
+<PRE>
+From: Poltorak Serguei &lt;poltorak@dataforce.net&gt;
+Subject: [Users] Using FreeS/WAN
+Date: Tue, 16 Oct 2001
+
+Hello.
+
+I'm using FreeS/WAN IPsec for half a year. I learned a lot of things about
+it and I think it would be interesting for someone to see the result of my
+experiments and usage of FreeS/WAN. If you find a mistake in this
+file, please e-mail me. And excuse me for my english... I'm learning.. :)
+
+I'll talk about vary simple configuration:
+
+addresses prefix = 192.168
+
+    lan1          sgw1     .0.0/24 (Internet)       sgw2            lan2
+  .1.0/24---[ .1.1 ; .0.1 ]===================[ .0.10 ; . 2.10 ]---.2.0/24
+
+
+We need to let lan1 see lan2 across Internet like it is behind sgw1. The
+same for lan2. And we need to do IPX bridge for Novel Clients and NDS
+synchronization.
+
+my config:
+------------------- ipsec.conf -------------------
+conn lan1-lan2
+        type=tunnel
+        compress=yes
+        #-------------------
+        left=192.168.0.1
+        leftsubnet=192.168.1.0/24
+        #-------------------
+        right=192.168.0.10
+        rightsubnet=192.168.2.0/24
+        #-------------------
+        auth=esp
+        authby=secret
+--------------- end of ipsec.conf ----------------
+
+ping .2.x from .1.y   (y != 1)
+It works?? Fine. Let's continue...
+
+Why y != 1 ?? Because kernel of sgw1 have 2 IP addresses and it will choose
+the first IP (which is used to go to Internet) .0.1 and the packet won't go
+through IPsec tunnel :(  But if do ping on .1.1 kernel will respond from
+that address (.1.1) and the packet will be tunneled. The same problem occurred then
+.2.x sends a packet to .1.2 which is down at the moment. What happens? .1.1
+sends ARP requesting .1.2... after 3 tries it send to .2.x an destunreach,
+but from his &quot;natural&quot; IP or .0.1 . So the error message won't be delivered!
+It's a big problem...
+
+Resolution... One can manipulate with ipsec0 or ipsec0:0 to solve the
+problem (if ipsec0 has .1.1 kernel will send packets correctly), but there
+are powerful and elegant iproute2 :) We simply need to change source address
+of packet that goes to other secure lan. This is done with
+
+ip route replace 192.168.2.0/24 via 192.168.0.10 dev ipsec0 src 192.168.1.1
+
+Cool!! Now it works!!
+
+The second step. We want install firewall on sgw1 and sgw2. Encryption of 
+traffic without security isn't a good idea. I don't use {left|right}firewall, 
+because I'm running firewall from init scripts.
+
+We want IPsec data between lan1-lan2, some ICMP errors (destination
+unreachable, TTL exceeded, parameter problem and source quench), replying on 
+pings from both lans and Internet, ipxtunnel data for IPX and of course SSH
+between sgw1 and sgw2 and from/to one specified host.
+
+I'm using ipchains. With iptables there are some changes.
+
+---------------- rc.firewall ---------------------
+#!/bin/sh
+#
+# Firewall for IPsec lan1-lan2
+#
+
+IPC=/sbin/ipchains
+ANY=0.0.0.0/0
+
+# left
+SGW1_EXT=192.168.0.1
+SGW1_INT=192.168.1.1
+LAN1=192.168.1.0/24
+
+# right
+SGW2_EXT=192.168.0.10
+SGW2_INT=192.168.2.10
+LAN2=192.168.2.0/24
+
+# SSH from and to this host
+SSH_PEER_HOST=_SOME_HOST_
+
+# this is for left. exchange these values for right.
+MY_EXT=$SGW1_EXT
+MY_INT=$SGW1_INT
+PEER_EXT=$SGW2_EXT
+PEER_INT=$SGW2_INT
+INT_IF=eth1
+EXT_IF=eth0
+IPSEC_IF=ipsec0
+MY_LAN=$LAN1
+PEER_LAN=$LAN2
+
+$IPC -F
+$IPC -P input DENY
+$IPC -P forward DENY
+$IPC -P output DENY
+
+# Loopback traffic
+$IPC -A input -i lo -j ACCEPT
+$IPC -A output -i lo -j ACCEPT
+
+# for IPsec SGW1-SGW2
+## IKE
+$IPC -A input -p udp -s $PEER_EXT 500 -d $MY_EXT 500 -i $EXT_IF -j ACCEPT
+$IPC -A output -p udp -s $MY_EXT 500 -d $PEER_EXT 500 -i $EXT_IF -j ACCEPT
+## ESP
+$IPC -A input -p 50 -s $PEER_EXT -d $MY_EXT -i $EXT_IF -j ACCEPT
+### we don't need this line ### $IPC -A output -p 50 -s $MY_EXT -d $PEER_EXT -i $EXT_IF -j ACCEPT
+## forward LAN1-LAN2
+$IPC -A forward -s $MY_LAN -d $PEER_LAN -i $IPSEC_IF -j ACCEPT
+$IPC -A forward -s $PEER_LAN -d $MY_LAN -i $INT_IF -j ACCEPT
+$IPC -A output -s $PEER_LAN -d $MY_LAN -i $INT_IF -j ACCEPT
+$IPC -A input -s $PEER_LAN -d $MY_LAN -i $IPSEC_IF -j ACCEPT
+$IPC -A input -s $MY_LAN -d $PEER_LAN -i $INT_IF -j ACCEPT
+$IPC -A output -s $MY_LAN -d $PEER_LAN -i $IPSEC_IF -j ACCEPT
+
+# ICMP
+#
+## Dest unreachable
+### from/to Internet
+$IPC -A input -p icmp --icmp-type destination-unreachable -s $ANY -d $MY_EXT -i $EXT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type destination-unreachable -s $MY_EXT -d $ANY -i $EXT_IF -j ACCEPT
+### from/to Lan
+$IPC -A input -p icmp --icmp-type destination-unreachable -s $ANY -d $MY_INT -i $INT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type destination-unreachable -s $MY_INT -d $ANY -i $INT_IF -j ACCEPT
+### from/to Peer Lan
+$IPC -A input -p icmp --icmp-type destination-unreachable -s $ANY -d $MY_INT -i $IPSEC_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type destination-unreachable -s $MY_INT -d $ANY -i $IPSEC_IF -j ACCEPT
+#
+## Source quench
+### from/to Internet
+$IPC -A input -p icmp --icmp-type source-quench -s $ANY -d $MY_EXT -i $EXT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type source-quench -s $MY_EXT -d $ANY -i $EXT_IF -j ACCEPT
+### from/to Lan
+$IPC -A input -p icmp --icmp-type source-quench -s $ANY -d $MY_INT -i $INT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type source-quench -s $MY_INT -d $ANY -i $INT_IF -j ACCEPT
+### from/to Peer Lan
+$IPC -A input -p icmp --icmp-type source-quench -s $ANY -d $MY_INT -i $IPSEC_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type source-quench -s $MY_INT -d $ANY -i $IPSEC_IF -j ACCEPT
+#
+## Parameter problem
+### from/to Internet
+$IPC -A input -p icmp --icmp-type parameter-problem -s $ANY -d $MY_EXT -i $EXT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type parameter-problem -s $MY_EXT -d $ANY -i $EXT_IF -j ACCEPT
+### from/to Lan
+$IPC -A input -p icmp --icmp-type parameter-problem -s $ANY -d $MY_INT -i $INT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type parameter-problem -s $MY_INT -d $ANY -i $INT_IF -j ACCEPT
+### from/to Peer Lan
+$IPC -A input -p icmp --icmp-type parameter-problem -s $ANY -d $MY_INT -i $IPSEC_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type parameter-problem -s $MY_INT -d $ANY -i $IPSEC_IF -j ACCEPT
+#
+## Time To Live exceeded
+### from/to Internet
+$IPC -A input -p icmp --icmp-type time-exceeded -s $ANY -d $MY_EXT -i $EXT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type time-exceeded -s $MY_EXT -d $ANY -i $EXT_IF -j ACCEPT
+### to Lan
+$IPC -A input -p icmp --icmp-type time-exceeded -s $ANY -d $MY_INT -i $INT_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type time-exceeded -s $MY_INT -d $ANY -i $INT_IF -j ACCEPT
+### to Peer Lan
+$IPC -A input -p icmp --icmp-type time-exceeded -s $ANY -d $MY_INT -i $IPSEC_IF -j ACCEPT
+$IPC -A output -p icmp --icmp-type time-exceeded -s $MY_INT -d $ANY -i $IPSEC_IF -j ACCEPT
+
+# ICMP PINGs
+## from Internet
+$IPC -A input -p icmp -s $ANY -d $MY_EXT --icmp-type echo-request  -i $EXT_IF -j ACCEPT
+$IPC -A output -p icmp -s $MY_EXT -d $ANY --icmp-type echo-reply  -i $EXT_IF -j ACCEPT
+## from LAN
+$IPC -A input -p icmp -s $ANY -d $MY_INT --icmp-type echo-request -i $INT_IF -j ACCEPT
+$IPC -A output -p icmp -s $MY_INT -d $ANY --icmp-type echo-reply  -i $INT_IF -j ACCEPT
+## from Peer LAN
+$IPC -A input -p icmp -s $ANY -d $MY_INT --icmp-type echo-request -i $IPSEC_IF -j ACCEPT
+$IPC -A output -p icmp -s $MY_INT -d $ANY --icmp-type echo-reply  -i $IPSEC_IF -j ACCEPT
+
+# SSH
+## from SSH_PEER_HOST
+$IPC -A input -p tcp -s $SSH_PEER_HOST -d $MY_EXT 22 -i $EXT_IF -j ACCEPT
+$IPC -A output -p tcp \! -y -s $MY_EXT 22 -d $SSH_PEER_HOST -i $EXT_IF -j ACCEPT
+## to SSH_PEER_HOST
+$IPC -A input -p tcp \! -y -s $SSH_PEER_HOST 22 -d $MY_EXT -i $EXT_IF -j ACCEPT
+$IPC -A output -p tcp -s $MY_EXT -d $SSH_PEER_HOST 22 -i $EXT_IF -j ACCEPT
+## from PEER
+$IPC -A input -p tcp -s $PEER_EXT -d $MY_EXT 22 -i $EXT_IF -j ACCEPT
+$IPC -A output -p tcp \! -y -s $MY_EXT 22 -d $PEER_EXT -i $EXT_IF -j ACCEPT
+## to PEER
+$IPC -A input -p tcp \! -y -s $PEER_EXT 22 -d $MY_EXT -i $EXT_IF -j ACCEPT
+$IPC -A output -p tcp -s $MY_EXT -d $PEER_EXT 22 -i $EXT_IF -j ACCEPT
+
+# ipxtunnel
+$IPC -A input -p udp -s $PEER_INT 2005 -d $MY_INT 2005 -i $IPSEC_IF -j ACCEPT
+$IPC -A output -p udp -s $MY_INT 2005 -d $PEER_INT 2005 -i $IPSEC_IF -j ACCEPT
+
+---------------- end of rc.firewall ----------------------
+
+To understand this we need to look on this scheme:
+
+           ++-----------------------&lt;----------------------------+
+           || ipsec0                                             |
+           \/                                                    |
+ eth0  +--------+    /---------/ yes  /---------/ yes +-----------------------+
+------&gt;| INPUT  |--&gt;/ ?local? /-----&gt;/ ?IPsec? /-----&gt;| decrypt decapsulate |
+ eth1  +--------+  /---------/      /---------/       +-----------------------+
+                       || no            || no
+                       \/               \/
+                  +----------+      +---------+        +-------+
+                  | routing  |      |  local  |        | local |
+                  | decision |      | deliver |        | send  |
+                  +----------+      +---------+        +-------+
+                       ||                                 ||
+                       \/                                 \/
+                   +---------+                       +----------+
+                   | forward |                       | routing  |
+                   +---------+                       | decision |
+                       ||                            +----------+
+                       ||                                  ||
+                       ++----------------&lt;-----------------++
+                       ||
+                       \/
+                   +--------+ eth0
+                   | OUTPUT | eth1
+                   +--------+ ipsec0
+                       ||
+                       \/
+                   /---------/ yes +-----------------------+
+                  / ?IPsec? /-----&gt;| encrypt encapsulate |
+                 /---------/       +-----------------------+
+                      || no                    ||
+                      ||                       ||
+                      ||                       \/   eth0, eth1
+                      ++-----------------------++--------------&gt;
+
+This explain how a packet traverse TCP/IP stack in IPsec capable kernel.
+
+FIX ME, please, if there are any errors
+
+Test the new firewall now.
+
+
+Now about IPX. I tried 3 programs for tunneling IPX: tipxd, SIB and ipxtunnel
+
+tipxd didn't send packets.. :(
+SIB and ipxtunnel worked fine :)
+With ipxtunnel there was a little problem. In sources there are an error.
+
+--------------------- in main.c ------------------------
+&lt;       bytes += p.len;
+---
+&gt;       bytes += len;
+--------------------------------------------------------
+
+After this FIX everything goes right...
+
+------------------- /etc/ipxtunnel.conf ----------------
+port    2005
+remote  192.168.101.97    2005
+interface eth1
+--------------- end of /etc/ipxtunnel.conf -------------
+
+I use IPX tunnel between .1.1 and .2.10 so we don't need to encrypt nor
+authenticate encapsulated IPX packets, it is done with IPsec.
+
+If you don't wont to use iproute2 to change source IP you need to use SIB
+(it is able to bind local address) or establish tunnel between .0.1 and
+.0.10 (external IPs, you need to do encryption in the program, but it isn't
+strong).
+
+For now I'm using ipxtunnel.
+
+I think that's all for the moment. If there are any error, please e-mail me: 
+poltorak@df.ru . It would be cool if someone puts the scheme of TCP/IP in
+kernel and firewall example on FreeS/WAN's manual pages.
+
+PoltoS
+</PRE>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="background.html">Previous</A>
+<A HREF="makecheck.html">Next</A>
+</BODY>
+</HTML>
diff --git a/doc/utils/cleanhtml.sed b/doc/utils/cleanhtml.sed
new file mode 100644
index 000000000..59d3866b8
--- /dev/null
+++ b/doc/utils/cleanhtml.sed
@@ -0,0 +1 @@
+/<STYLE>/,/<\/STYLE>/d
diff --git a/doc/utils/cleanhtml.sh b/doc/utils/cleanhtml.sh
new file mode 100755
index 000000000..a3ea2afac
--- /dev/null
+++ b/doc/utils/cleanhtml.sh
@@ -0,0 +1,12 @@
+# script to clean up HTML files
+# removes formatting added by htmldoc
+#
+# first argument is sedscript to use
+f=$1
+shift
+# remaining args are files to process
+for i
+do
+	sed -f $f $i > tmp
+	mv tmp $i
+done
diff --git a/doc/utils/contents.awk b/doc/utils/contents.awk
new file mode 100644
index 000000000..5cc07f246
--- /dev/null
+++ b/doc/utils/contents.awk
@@ -0,0 +1,109 @@
+# table-of-contents extractor
+# Copyright (C) 1999  Sandy Harris.
+# 
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 2 of the License, or (at your
+# option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+# 
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+# or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# RCSID $Id: contents.awk,v 1.1 2004/03/15 20:35:24 as Exp $
+BEGIN	{
+	# initialise indent counter
+	indent = 0
+	# define variables for section breaks
+	b0 = "==================================================="
+	b1 = "---------------------------------------------------"
+	b2 = "\t------------------------------------------"
+	# TURN OFF HTML formatting
+	print "<html>"
+	print "<body>"
+	print "<pre>"
+	# print a header
+	blurb() 
+	print "Section headings printed, indentation shows structure"
+}
+# start of new file
+FNR == 1 {
+	print b0
+	print "HTML file: " "<a href=\"" FILENAME "\">" FILENAME "</a>"
+	print b1
+}
+# print header lines
+# actual printing is done by tagged() function
+# which adds tag if last line was <a name=...>
+$0 ~/<h1>/	{
+	text = $0
+	tabs = ""
+	gsub(/.*<h1>/, "", text)
+	gsub(/<\/h1>/, "", text)
+	tagged( text )
+}
+$0 ~/<h2>/	{
+	text = $0
+	tabs = "\t"
+	gsub(/.*<h2>/, "", text)
+	gsub(/<\/h2>/, "", text)
+	tagged(text)
+}
+$0 ~/<h3>/	{
+	text = $0
+	tabs = "\t\t"
+	gsub(/.*<h3>/, "", text)
+	gsub(/<\/h3>/, "", text)
+	tagged(text)
+}
+$0 ~/<h4>/	{
+	text = $0
+	tabs = "\t\t\t"
+	gsub(/.*<h4>/, "", text)
+	gsub(/<\/h4>/, "", text)
+	tagged( text )
+}
+# if current line is not header
+# and we have stored tag from <a name=..> line
+# make link to that tag
+$0 !~ /<h[1-4]/ 	{
+	if( length(name) )
+		print "[ <a href=\"" FILENAME "#" name "\">" name "</a>" " ]"
+	name = ""
+}
+# for <a name=whatever> lines
+# save name in a variable
+# not printed until we see next line
+$0 ~ /<a name=.*>/	{
+	name = $0
+	# strip anything before or after name tag
+	gsub(/.*<a name=/, "", name)
+	gsub(/>.*/, "", name)
+	# strip quotes off name
+	gsub(/^"/, "", name)
+	gsub(/"$/, "", name)
+}
+END	{
+	print b0
+	blurb()
+	print "Docs & script by Sandy Harris"
+	print "</pre>"
+	print "</body>"
+	print "</html>"
+}
+
+function tagged(text)	{	# print header with tag if available
+	if( length(name) )	# > 0 if previous line was a name
+		print tabs "<a href=\"" FILENAME "#" name "\">" text "</a>"
+	else
+		print tabs text
+	name = ""
+}
+
+function blurb()	{
+	print "Linux FreeSWAN HTML documents"
+	print "Automatically generated Table of Contents"
+	print "Bug reports to the mailing list: linux-ipsec@clinet.fi"
+	print "<p>"
+}
diff --git a/doc/utils/four2perm.1 b/doc/utils/four2perm.1
new file mode 100644
index 000000000..1e5263b5b
--- /dev/null
+++ b/doc/utils/four2perm.1
@@ -0,0 +1,20 @@
+.TH FOUR2PERM 1 "August 1999"
+.\" RCSID $Id: four2perm.1,v 1.1 2004/03/15 20:35:24 as Exp $
+.SH NAME
+four2perm - generate permuted index from four-field lines
+.SH SYNOPSIS
+.B four2perm
+.SH DESCRIPTION
+.I four2perm
+expects input lines with four tab-separated fields, such as that
+created from HTML files by html2four(1). Given that, it does most
+of the work of generating a permuted index, gets things close
+enough that a simple pipeline through sort(1) and awk(1) can
+finish the job.
+.SH SEE ALSO
+.hy 0
+html2four(1)
+.SH HISTORY
+Written for the Linux FreeS/WAN project
+<http://www.xs4all.nl/~freeswan/>
+by Sandy Harris.
diff --git a/doc/utils/four2perm.c b/doc/utils/four2perm.c
new file mode 100644
index 000000000..5b575c1b5
--- /dev/null
+++ b/doc/utils/four2perm.c
@@ -0,0 +1,140 @@
+#include <ctype.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+#define MAX_LINE  512
+
+void die( char * ) ;
+
+char buffer[MAX_LINE+1] ;
+char *prog_name ;
+
+void die( char *message )
+{
+	fflush(stdout) ;
+	fprintf(stderr, "%s: %s\n", prog_name, message) ;
+	exit(1) ;
+}
+
+int main(int argc, char* argv[])
+{
+	int errors ;
+	prog_name = *argv ;
+	if( argc != 1 )
+		die("pure filter, takes no arguments") ;
+	errors = 0 ;
+	while( fgets(buffer, MAX_LINE, stdin))
+		errors += do_line(buffer) ;
+	exit(errors ? 1 : 0 ) ;
+}
+
+int do_line(char *data)
+{
+	char *p, *q, *r, *end, *before, *after ;
+	// expecting two tab-separated fields
+	// point r to 2nd, null terminate 1st
+	for( r = data ; *r && *r != '\t' ; r++ )
+		;
+	if( *r != '\t' )
+		return(1) ;
+	end = r++ ;
+	*end = '\0' ;
+	for( q = r ; *q ; q++ )
+		if( *q == '\n' )
+			*q = '\0' ;
+	if( !strlen(r) )
+		return(1) ;
+	// within 1st, parse as space-separated
+	// p will point to current word, q past its end
+	// before & after point to rest of text
+	// spaces converted to nulls & back as req'd
+	before = "" ;
+	for( p = data ; p < end ; p = q + 1 )	{
+		if( p > data )	{
+			before = data ;
+			p[-1] = '\0' ;
+		}
+		// find end of word
+		for( q = p ; *q && *q != ' ' ; q++ )
+			;
+		if( q == end )
+			after = "" ;
+		else if( q < end )	{
+			after = q + 1 ;
+			*q = '\0' ;
+		}
+		else	assert(0) ;
+		print_line(before, p, after, r) ;
+		if( q < end )
+			*q = ' ' ;
+		if( p > data )
+			p[-1] = ' ' ;
+	}
+	return(0) ;
+}
+
+// print formatted line for permuted index
+// two tab-separated fields
+//    1st is sort key
+//    2nd is printable line
+// pipe it through something like
+//   sort -F | awk -F '\t' '{print $2}'
+// to get final output
+
+print_line( char *before, char *word, char *after, char *tag)
+{
+	int i , x, y, z ;
+/*
+	printf("%s\t%s\t%s\t%s\n", before, word, after, tag) ;
+*/
+	if( list_word(word) )
+		return ;
+	x = strlen(before) ;
+	y = strlen(word) ;
+	z = strlen(after) ;
+	// put in sortable field
+	// strip out with awk after sorting
+	printf("%s %s\t", word, after) ;
+	// shorten before string to fit field
+	for( ; x > 30 ; x-- )
+		before++ ;
+	printf("%30s", before) ;
+	// print keyword, html tagged
+	printf("  %s%s</a>  ", tag, word) ;
+	// padding, outside tag
+	for( ; y < 18 ; y++ )
+		putchar(' ') ;
+	if( z )
+		printf("%s", after) ;
+	printf("\n") ;
+}
+
+// avoid indexing on common English words
+
+char *list[] = {
+		"the", "of", "a", "an", "to", "and",  "or", "if", "for", "at",
+		"am", "is", "are", "was", "were", "have", "has", "had", "be", "been",
+		"on", "some", "with", "any", "into", "as", "by", "in", "out",
+		"that", "then", "this", "that", "than", "these", "those",
+		"he", "his", "him", "she", "her", "hers", "it", "its",
+		"&", "", "+", "-", "=", "--", "<", ">", "<=", ">=",
+		"!", "?", "#", "$", "%", "/", "\\", "\"", "\'",
+		NULL
+		} ;
+// interrogative words like "how" and "where" deliberately left out of
+// above list because users might want to search for "how to..." etc.
+
+// return 1 if word in list, else 0
+// case-insensitive comparison
+
+list_word( char *p )
+{
+	char **z ;
+	for( z = list ; *z != NULL ; z++ )
+		if( ! strcasecmp( p, *z ) )
+			return 1 ;
+	return 0 ;
+}
+
diff --git a/doc/utils/html2four.1 b/doc/utils/html2four.1
new file mode 100644
index 000000000..456ac5e98
--- /dev/null
+++ b/doc/utils/html2four.1
@@ -0,0 +1,26 @@
+.TH HTML2FOUR 1 "August 1999"
+.\" RCSID $Id: html2four.1,v 1.1 2004/03/15 20:35:24 as Exp $
+.SH NAME
+html2four - extract headers from HTML files into four-field lines
+.SH SYNOPSIS
+.B html2four
+[-digit] file*
+command [ argument ...]
+.SH DESCRIPTION
+.I html2four
+extracts information from HTML files and writes it out with four
+tab-separated fields: filename, last label (<a name=> tag) seen,
+header tag type (H[0-9]), and header text. This is an intermediate
+format convenient for generating a permuted index with four2perm(1)
+or a table of contents with a simple awkscript.
+
+The only option is a digit to limit the header levels extracted.
+For example, with -3 only h1, h2, h3 tags are taken. By default,
+it takes h[0-9], though HTML only defines levels 1 to 6.
+.SH SEE ALSO
+.hy 0
+four2perm(1)
+.SH HISTORY
+Written for the Linux FreeS/WAN project
+<http://www.xs4all.nl/~freeswan/>
+by Sandy Harris.
diff --git a/doc/utils/html2four.c b/doc/utils/html2four.c
new file mode 100644
index 000000000..fc1100d01
--- /dev/null
+++ b/doc/utils/html2four.c
@@ -0,0 +1,298 @@
+/*
+	extract headers from HTML files
+	in format suitable for turning into permuted index
+*/
+
+#include <ctype.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+/*
+	maximum sizes for input line and for name in <a> tag
+*/
+#define MAX_LINE  512
+#define MAX_NAME   64
+
+/*
+	functions
+	all return 0 for OK, 1 for errors
+*/
+int do_file( char *, FILE * ) ;
+int parse_line( char * ) ;
+int print_line( char *, char *) ;
+int print_header_problem( char * ) ;
+int sanity() ;
+
+void die( char * ) ;
+
+char	*prog_name ;
+int	max_level ;
+char	*current_file ;
+
+int main(int argc, char* argv[])
+{
+	char *p ;
+	int temp, done, status ;
+	FILE *fp ;
+
+	prog_name = *argv ;
+	argc--,argv++ ;
+
+	max_level = 9 ;	
+	if(argc && *argv )	{
+		p = *argv ;
+		if( p[0] == '-' )	{
+			if( isdigit(p[1]) && p[2] == '\0' )	{
+				max_level = p[1] - 0 ;
+				argc-- ;
+				argv++ ;
+			}
+			else die("unknown option") ;
+	}	}
+
+	status = done = 0 ;
+	if( argc == 0)	{
+		if( (status = do_file("STDIN", stdin)) == 0 )
+			done++ ;
+	}
+	else	{
+/*
+		printf("ARGC = %d\n", argc ) ;
+*/
+		while( argc-- )	{
+			p = *argv++ ;
+/*
+			printf("ARGV P %s %s\n", *argv, p) ;
+*/
+			if( p == NULL )	{
+				fprintf(stderr, "%s: null filename pointer\n", prog_name) ;
+				status++ ;
+			} 
+			else if( (fp = fopen(p,"r")) == NULL )	{
+				fprintf(stderr, "%s: cannot open file %s\n", prog_name, p) ;
+				status++ ;
+			}
+			else	{
+				if( (temp = do_file(p, fp)) != 0 )
+					status++ ;
+				done++ ;
+				fclose(fp) ;
+			}
+			fflush(stderr) ;
+			fflush(stdout) ;
+		}
+	}
+/*
+	printf("%s: %d files processed, %d with errors\n", prog_name, done, status) ;
+*/
+	return( status ? 1 : 0 ) ;
+}
+
+void die( char *message )
+{
+	fflush(stdout) ;
+	fprintf(stderr, "%s: %s\n", prog_name, message) ;
+	exit(1) ;
+}
+
+int header_flags[10] ;
+int in_header ;
+
+char buffer[MAX_LINE+1] ;
+char label[MAX_NAME+1] ;
+
+int do_file( char *file, FILE *fp )
+{
+	int i, status, x, y ;
+	char *base, *p ;
+
+	status = 0 ;
+	in_header = 0 ;
+	label[0] = '\0' ;
+	for( i = 0 ; i < 10 ; i++ )
+		header_flags[i] = 0 ;
+	current_file = file ;
+
+	while( base = fgets(buffer, MAX_LINE, fp) )	{
+		// count < and > characters in line
+		for( x = y = 0, p = base ; *p ; p++ )
+			switch( *p )	{
+				case '<':
+					x++ ;
+					break ;
+				case '>':
+					y++ ;
+					break ;
+				default:
+					break ;
+			}
+		// skip line if no < or >
+		if( x == 0 && y == 0 )
+			continue ;
+		// report error for unequal count
+		else if( x != y )	{
+			if( strncmp( base, "<!--", 4) && strncmp(base, "-->", 3) )	{
+				fflush(stdout) ;
+				fprintf(stderr, "%s in file %s: unequal < > counts %d %d\n",
+					prog_name, file, x, y ) ;
+				fprintf(stderr, "%s: %s\n", prog_name, base) ;
+				fflush(stderr) ;
+				status = 1 ;
+			}
+			continue ;
+		}
+		// parse lines containing tags
+		else
+			if( parse_line(base) )
+				status = 1 ;
+		// check that header labelling is sane
+		for( i = x = y = 0 ; i < 10 ; i++ )	{
+			// count non-zero entries
+			if( x = header_flags[i] )
+				y++ ;
+			// should be in 0 or 1 headers at a time
+			if( x > 1 || x < 0 )
+				status = 1 ;
+		}
+		if( y > 1 )
+			status = 1 ;
+	}
+	return status ;
+}
+
+int parse_line( char *data )
+{
+	char *p, *q, *end ;
+	int x ;
+
+	// set end pointer
+	for( end = data ; *end ; end++ )
+		;
+	// trim off trailing returns or newlines
+	for( p = end - 1, q = end ; q > data ; p--,q-- )	{
+		switch( *p )	{
+			case '\012':
+			case '\015':
+				*p = '\0' ;
+				continue ;
+			default:
+				break ; // out of switch()
+		}
+		break ; // out of for()
+	}
+	end = q ;
+	p = data ;
+	while( p < end )	{
+		// find tag delimiters
+		if( *p == '<')	{
+			for( q = p + 1 ; *q ; q++ )
+				if( *q == '<' || *q == '>' )
+					break ;
+			// if we find another '<'
+			// restart tag search from it
+			if( *q == '<' )	{
+				p = q ;
+				continue ;
+			}
+			// "<>" is not interesting
+			if( q == p + 1 )	{
+				fflush(stdout) ;
+				fprintf(stderr, "%s: null tag\n", prog_name) ;
+				fprintf(stderr, "%s: line\n", prog_name, data) ;
+				fflush(stderr) ;
+				p = q + 1 ;
+				continue ;
+			}
+			// ignore delimiters once found
+			*q = '\0' ;
+			p++ ;
+			// p points to tag contents, null terminated
+			switch( *p )	{
+			// save contents of <a name= > tags
+			case 'a' :
+			case 'A' :
+				if(	 p[1] == ' ' &&
+					(p[2] == 'n' || p[2] == 'N') &&
+					(p[3] == 'a' || p[3] == 'A') &&
+					(p[4] == 'm' || p[4] == 'M') &&
+					(p[5] == 'e' || p[5] == 'E') &&
+					 p[6] == '=' )
+				strncpy(label, p + 7, MAX_NAME) ;
+				break ;
+			case 'b' :
+			case 'B' :
+				if(	in_header && strlen(p) == 2 &&
+					(p[1] == 'r' || p[1] == 'R') )
+					putchar(' ') ;
+				break ;
+			// header tags
+			case 'h' :
+			case 'H' :
+				if( strlen(p) == 2 && isdigit(p[1]) )	{
+					if( in_header )
+						fprintf(stderr, "%s: bad header nesting in %s\n",
+							prog_name, current_file) ; 
+					x = p[1] - '0' ;
+					in_header = 1 ;
+					header_flags[x]++ ;
+					printf("%s\t%s\tH%d\t", current_file, label, x) ;
+				}
+				break ;
+			// only care about end-of-header
+			case '/':
+				p++ ;
+				switch( *p )	{
+				case 'h' :
+				case 'H' :
+					if( strlen(p) == 2 && isdigit(p[1]) )	{
+						if( ! in_header )
+							fprintf(stderr, "%s: bad header nesting in %s\n",
+								prog_name, current_file) ; 
+						x = p[1] - '0' ;
+						in_header = 0 ;
+						header_flags[x]-- ;
+						printf("\n") ;
+					}
+					break ;
+				}
+				break ;
+			// uninteresting tag, look for next
+			default :
+				break ;
+			}
+		// tag done, point p beyond it
+		p = q + 1 ;
+		}
+		else if( in_header )	{
+			if( isprint(*p) && *p != '\n' )
+				putchar(*p) ;
+			else
+				putchar(' ');
+			p++ ;
+		}
+		else
+			p++ ;
+	}
+	return(0) ;
+}
+
+int print_line( char *tag, char *text)
+{
+	printf("%%s\ts\t%s\t%s\t\n", current_file, label, tag, text) ;
+	return 0 ;
+}
+
+int print_header_problem( char *file )
+{
+	int i ;
+	fflush(stdout) ;
+	fprintf(stderr, "%s: HEADER TAG PROBLEM in file %s\n", prog_name, file) ;
+	fprintf(stderr, "%s: counts", prog_name) ;
+	for ( i = 0 ; i < 10 ; i++ )
+		fprintf(stderr, "\t%d", i) ;
+	fprintf(stderr,"\n") ;
+	fflush(stderr) ;
+	return(0) ;
+}
+
diff --git a/doc/utils/html2txt.sed b/doc/utils/html2txt.sed
new file mode 100644
index 000000000..fc4940991
--- /dev/null
+++ b/doc/utils/html2txt.sed
@@ -0,0 +1,86 @@
+# skip over header material
+# Copyright (C) 1999  Sandy Harris.
+# 
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 2 of the License, or (at your
+# option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+# 
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+# or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# RCSID $Id: html2txt.sed,v 1.1 2004/03/15 20:35:24 as Exp $
+/<head>/,/<\/head>/d
+/<HEAD>/,/<\/HEAD>/d
+/<^body$>/d
+s/<body>//
+# eliminate possible DOS crud
+s/\015//
+#get rid of HTML comments
+s/<!--.*-->//
+/<!--/,/-->/d
+# citations & emphasis -> visible
+s/<cite>/"/g
+s/<\/cite>/"/g
+s/<em>/*/g
+s/<\/em>/*/g
+s/<strong>/!->/g
+s/<\/strong>/<-!/g
+s/<b>//g
+s/<\/b>//g
+s/<blockquote>/Quote -->/
+s/<\/blockquote>/<-- End Quote/
+# mark headers
+s/<h1>/Header 1:  /
+s/<h2>/Header 2:  /
+s/<h3>/Header 3:  /
+s/<h4>/Header 4:  /
+s/<h5>/Header 5:  /
+s/<h6>/Header 6:  /
+# remove some cruft
+s/<\/h[1-6]>//
+/^<a name=[a-zA-Z0-9\.]*>$/d
+s/<a name=[a-zA-Z0-9\.]*>//
+# definition lists
+s/<dl>//
+s/<\/dl>//
+s/^<dt>$/-----------------------------------------/
+s/^<dt>/-----------------------------------------\
+/
+s/<dd>/\
+/
+# other types of lists
+s/<li>//
+s/<ol>//
+s/<ul>//
+s/<\/ol>//
+s/<\/ul>//
+# tables
+s/<table>//
+s/<\/table>//
+s/<tr>//
+s/<td>/	/g
+# line break and paragraph markers
+# different subst depending where they are in line
+s/^<br>//
+s/<br>$//
+s/<br>/\
+/
+s/^<p>$//
+s/<p>$/\
+/
+s/^<p>/\
+/
+s/<p>/\
+\
+/
+s/<\/p>//
+# remove more cruft
+s/<pre>//
+s/<\/pre>//
+s/<\/body>//
+s/<\/html//
+s/<\/BODY>//
+s/<\/HTML>//
diff --git a/doc/utils/killtoodeepcontents.pl b/doc/utils/killtoodeepcontents.pl
new file mode 100644
index 000000000..a6fe551d6
--- /dev/null
+++ b/doc/utils/killtoodeepcontents.pl
@@ -0,0 +1,59 @@
+#!/usr/bin/perl
+
+$toc=0;
+$memo=0;
+
+while(<>) {
+  if(0 && /^Status of this Memo/) {
+    $memo=1;
+    print;
+    next;
+  }
+    
+  if(/^Table of Contents/) {
+    print ".bp\n";
+    $toc=1;
+    print;
+    next;
+  }
+  
+  if(!$toc && !$memo) {
+    print;
+    next;
+  }
+
+  if($toc) {
+    if(/^[0-9]*\.[0-9]*\.[0-9]* / ||
+#       /^[0-9]*\.[0-9]* / ||
+       /^[0-9]*\.[0-9]*\.[0-9]*\.[0-9]* /) {
+      next;
+    }
+
+    if(/^14./) {
+      $toc=0;
+    }
+    if(/^\.bp/) {
+      next;
+    }
+    print;
+  }
+
+  if($memo) {
+    if(/^\.bp/) {
+      next;
+    }
+    
+    if(/^Copyright Notice/) {
+      print ".fi\n";
+      print "This memo provides information for the Internet community.  It does\n";
+      print "not specify an Internet standard of any kind.  Distribution of this\n";
+      print "memo is unlimited.\n";
+      print "\n.ti 0\n";
+
+      print;
+
+      $memo=0;
+      next;
+    }
+  }
+}
diff --git a/doc/utils/man2html.script b/doc/utils/man2html.script
new file mode 100755
index 000000000..515911c81
--- /dev/null
+++ b/doc/utils/man2html.script
@@ -0,0 +1,48 @@
+#!/bin/sh
+
+# Assumes man2html command in path
+# That is a Perl script downloadable from
+# http://www.oac.uci.edu/indiv/ehood/man2html.html
+
+# also uses our man_xref utility
+
+case $# in
+2)	;;
+*)	echo "Usage: $0 mantree destdir" >&2 ; exit 2	;;
+esac
+
+mkdir -p $2
+rm -f $2/*
+
+# handle all sections just in case
+# only 3 5 8 expected 
+for i in `find $1 -name 'ipsec*.[1-9]'`
+do
+	b=`basename $i`
+	# then parse that into section number s
+	# and name n
+	case $b in
+		*.1)	s=1 ;;
+		*.2)	s=2 ;;
+		*.3)	s=3 ;;
+		*.4)	s=4 ;;
+		*.5)	s=5 ;;
+		*.6)	s=6 ;;
+		*.7)	s=7 ;;
+		*.8)	s=8 ;;
+		*.9)	s=9 ;;
+		*)	echo "$0 has lost its mind" ; exit 1 ;;
+	esac
+	n=`basename $b \.$s`
+	# the echos are a kluge
+	# without them, the first section head is not tagged
+	(echo ; echo ; man $s $n ) | man2html > $2/$b.html
+done
+# man2html doesn't convert man page cross-references such as
+# ipsec.conf(5) into HTML links
+# So post-process to do that.
+for i in $2/*.html
+do
+	../utils/man_xref $i > temp
+	mv temp $i
+done
diff --git a/doc/utils/man_xref.c b/doc/utils/man_xref.c
new file mode 100644
index 000000000..fc3afb696
--- /dev/null
+++ b/doc/utils/man_xref.c
@@ -0,0 +1,125 @@
+#include <stdio.h>
+#include <ctype.h>
+#include <assert.h>
+
+/*
+	look through HTMLized man pages
+	convert references like man(1) into HTML links
+
+	somewhat quick & dirty code
+	various dubious assumptions made:
+
+	[a-zA-Z0-9\-_\.]* defines legal characters in name
+	pagename(x) corresponds to pagename.x.html
+	(Fine *if* it's been converted by my scripts)
+	x in the above must be a single digit
+	(or we ignore it, which does no damage)
+	Lazy parsing: malloc() enough RAM to read in whole file
+	Limited syntax: exactly one input file, results to stdout 
+
+	Sandy Harris
+*/
+
+int do_file( char *, char *) ;
+
+main(int argc, char **argv)
+{
+	FILE *in ;
+	char *progname;
+	long lsize ;
+	size_t size, nread;
+	char *buffer, *bufend ; 
+	progname = *argv ;
+	if( argc != 2 )	{
+		fprintf(stderr,"usage: %s input-file\n", progname);
+		exit(1) ;
+	}
+	if( (in = fopen(argv[1],"r")) == NULL )	{
+		fprintf(stderr,"%s Can't open input file\n", progname);
+		exit(2) ;
+	}
+	if( (lsize = fseek(in, 0L, SEEK_END)) < 0L )	{
+		fprintf(stderr,"%s fseek() fails\n", progname);
+		exit(3) ;
+	}
+	lsize = ftell(in) ;
+	rewind(in) ;
+	size = (size_t) lsize ;
+	if( lsize != (long) size )	{
+		fprintf(stderr,"%s file too large\n", progname);
+		exit(4) ;
+	}
+	if( (buffer = (char *) malloc(size)) == NULL)	{
+		fprintf(stderr,"%s malloc() failed\n", progname);
+		exit(5) ;
+	}
+	bufend = buffer + size ;
+	if( (nread = fread(buffer, size, 1, in)) != 1) { 
+		fprintf(stderr,"%s fread() failed\n", progname);
+		exit(6) ;
+	}
+	do_file(buffer,bufend);
+}
+
+do_file(char *start, char *end)
+{
+	/* p is where to start parsing, one past last output	*/
+	/* q is how far we've parsed				*/
+	char *p, *q ;
+	int value ;
+	for( p = q = start ; p < end ; q = (q<end) ? (q+1) : q  )	{
+		/* if p is beyond q, catch up	*/
+		if( q < p )
+			continue ;
+		/* move q ahead until we know if we've got manpage name */
+		if( isalnum(*q) )
+			continue ;
+		switch(*q)	{
+			/* can appear in manpage name	*/
+			case '.':
+			case '_':
+			case '-':
+			case '(':
+				continue ;
+				break ;
+			/* whatever's between p and q
+			   is not a manpage name
+			   so output it
+			*/
+			default:
+				/* leave p one past output	*/
+				for( ; p <= q ; p++ )
+					putchar(*p);
+				break ;
+			/* we may have a manpage name	*/
+			case ')':
+				value = do_name(p,q);
+				if(value)	{
+					p = q ;
+					p++ ;
+				}
+				/* unreached with current do_name() */
+				else
+					for( ; p <= q ; p++ )
+						putchar(*p);
+				break ;
+}	}	}
+
+do_name(char *p, char *q)
+{
+	*q = '\0' ;
+	/* if end of string matches RE ([0-9])
+	   with at least one legal character before it
+	   add HTML xref stuff
+	*/
+	if( (q-p > 3) && isdigit(q[-1]) && (q[-2]=='('))	{
+		q[-2] = '\0' ;
+		q-- ;  
+		printf("<a href=\"%s.%s.html\">", p, q);
+		printf("%s(%s)", p, q);
+		printf("</a>");
+	}
+	// otherwise just print string
+	else	printf("%s)", p);
+	return 1 ;
+}
diff --git a/doc/utils/mkhtmlman b/doc/utils/mkhtmlman
new file mode 100755
index 000000000..6d73bd1f2
--- /dev/null
+++ b/doc/utils/mkhtmlman
@@ -0,0 +1,44 @@
+#!/bin/sh
+# gathers manpages up into dir, converts them to HTML, including interlinking
+# Assumes RedHat6.0 man2html available.
+
+PATH=/usr/local/bin:/bin:/usr/bin:/usr/contrib/bin:$PATH ; export PATH
+
+# note, this is always run from freeswan/doc.
+
+TOPDIR=..
+
+case $# in
+1)	exit 0	;;
+0)	echo "Usage: $0 destdir manpage ..." >&2 ; exit 1	;;
+esac
+
+dir=$1
+shift
+mkdir -p $dir
+rm -f $dir/*
+
+for f
+do
+	b=`basename $f`
+	case $b in
+	ipsec*)			;;	# ipsec.8, ipsec.conf.5, etc.
+	*)	b="ipsec_$b"	;;
+	esac
+	cp $f $dir/$b
+	$TOPDIR/packaging/utils/manlink $f | while read from to
+	do
+	    (cd $dir; ln -s ../$f $to)
+	done
+done
+
+# build the html (sed mess fixes overly-smart man2html's crud)
+refpat='"http://localhost/cgi-bin/man/man2html?\([1-8]\)+\([^"]*\)"'
+for f in $dir/*.[1-8]
+do
+	echo Processing $f
+	man2html <$f | sed 's;'"$refpat"';"\2.\1.html";g' >$f.html
+done
+
+# remove the source files (must wait until after all builds, due to symlinks)
+rm -f $dir/*.[1-8]
diff --git a/doc/utils/perm1.awk b/doc/utils/perm1.awk
new file mode 100644
index 000000000..d9f8f5565
--- /dev/null
+++ b/doc/utils/perm1.awk
@@ -0,0 +1 @@
+{ print $4 "\t<a href=\"" $1 "#" $2 "\">" }
diff --git a/doc/utils/perm2.awk b/doc/utils/perm2.awk
new file mode 100644
index 000000000..3c55fef11
--- /dev/null
+++ b/doc/utils/perm2.awk
@@ -0,0 +1,46 @@
+BEGIN   {
+        print "<html>\n<body>"
+        print "<h2>Permuted Index of HTML headers in FreeS/WAN documents</h2>"
+        print "<h3>Jump to a letter</h3>"
+        print "<center><big><strong>"
+        print "<a href=\"#0\">numeric</a>"
+        print "<a href=\"#a\">A</a>"
+        print "<a href=\"#b\">B</a>"
+        print "<a href=\"#c\">C</a>"
+        print "<a href=\"#d\">D</a>"
+        print "<a href=\"#e\">E</a>"
+        print "<a href=\"#f\">F</a>"
+        print "<a href=\"#g\">G</a>"
+        print "<a href=\"#h\">H</a>"
+        print "<a href=\"#i\">I</a>"
+        print "<a href=\"#j\">J</a>"
+        print "<a href=\"#k\">K</a>"
+        print "<a href=\"#l\">L</a>"
+        print "<a href=\"#m\">M</a>"
+        print "<a href=\"#n\">N</a>"
+        print "<a href=\"#o\">O</a>"
+        print "<a href=\"#p\">P</a>"
+        print "<a href=\"#q\">Q</a>"
+        print "<a href=\"#r\">R</a>"
+        print "<a href=\"#s\">S</a>"
+        print "<a href=\"#t\">T</a>"
+        print "<a href=\"#u\">U</a>"
+        print "<a href=\"#v\">V</a>"
+        print "<a href=\"#w\">W</a>"
+        print "<a href=\"#x\">X</a>"
+        print "<a href=\"#y\">Y</a>"
+        print "<a href=\"#z\">Z</a>"
+        print "</strong></big></center>"
+        print "<hr>"
+        print "<pre>"
+        print "<a name=0>"
+        old =""
+        }
+{       x = tolower(substr($1,1,1))
+        if( (x ~ /[a-zA-Z]/) && (x != old) )
+                print "<a name=" x ">" $2
+        else
+                print $2
+        old = x
+        }
+END     { print "</pre>\n</html>" }
diff --git a/doc/utils/rfc_pg.c b/doc/utils/rfc_pg.c
new file mode 100644
index 000000000..448cc1a36
--- /dev/null
+++ b/doc/utils/rfc_pg.c
@@ -0,0 +1,76 @@
+/*
+ *  $Header: /var/cvsroot/strongswan/doc/utils/rfc_pg.c,v 1.1 2004/03/15 20:35:24 as Exp $
+ *
+ * from 2-nroff.template file.
+ *
+ *  Remove N lines following any line that contains a form feed (^L).
+ *  (Why can't this be done with awk or sed?)
+ *
+ *  OPTION:
+ *	-n#	Number of lines to delete following each ^L (0 default).
+ * $Log: rfc_pg.c,v $
+ * Revision 1.1  2004/03/15 20:35:24  as
+ * added files from freeswan-2.04-x509-1.5.3
+ *
+ * Revision 1.1  2002/07/23 18:42:43  mcr
+ * 	required utility from IETF to help with formatting of drafts.
+ *
+ */
+#include <stdio.h>
+
+#define FORM_FEED	'\f'
+#define OPTION		"n:N:"		/* for getopt() */
+
+extern char *optarg;
+extern int optind;
+
+main(argc, argv)
+int	argc;
+char	*argv[];
+{
+  int	c,				/* next input char */
+	nlines = 0;			/* lines to delete after ^L */
+  void	print_and_delete();		/* print line starting with ^L,
+					   then delete N lines */
+
+/*********************** Process option (-nlines) ***********************/
+
+  while ((c = getopt(argc, argv, OPTION)) != EOF)
+    switch(c)
+    {
+      case 'n' :
+      case 'N' :  nlines = atoi(optarg);
+		  break;
+    }
+/************************* READ AND PROCESS CHARS **********************/
+
+  while ((c = getchar()) != EOF)
+    if (c == FORM_FEED)
+      print_and_delete(nlines);		/* remove N lines after this one */
+    else
+      putchar(c);			/* we write the form feed */
+  exit(0);
+}
+
+
+/*
+ *  Print rest of line, then delete next N lines.
+ */
+void print_and_delete(n)
+int  n;					/* nbr of lines to delete */
+{
+  int	c,				/* next input char */
+	cntr = 0;			/* count of deleted lines */
+
+  while ((c = getchar()) != '\n')	/* finish current line */
+    putchar(c);
+  putchar('\n');			/* write the last CR */
+  putchar(FORM_FEED);
+
+  for ( ; cntr < n; cntr++)
+    while ((c = getchar()) != '\n')
+      if (c == EOF)
+	exit(0);			/* exit on EOF */
+  putchar(c);				/* write that last CR */
+}
+
diff --git a/doc/utils/xref.sed b/doc/utils/xref.sed
new file mode 100644
index 000000000..8c3b442cc
--- /dev/null
+++ b/doc/utils/xref.sed
@@ -0,0 +1,56 @@
+# turn end-of xref tags into <*>
+# Copyright (C) 1999  Sandy Harris.
+# 
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 2 of the License, or (at your
+# option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+# 
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+# or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# RCSID $Id: xref.sed,v 1.1 2004/03/15 20:35:24 as Exp $
+s/<\/a>/<*>/g
+# delete all xrefs that point
+# within our document set
+s/<a href="..\/Internet-docs\/rfc....\.txt">//
+# in same doc
+s/<a href="#[a-zA-Z0-9\.]*">//
+# pointer into another doc
+s/<a href="DES.html#[a-zA-Z0-9\.]*">//
+s/<a href="RFCs.html#[a-zA-Z0-9\.]*">//
+s/<a href="WWWref.html#[a-zA-Z0-9\.]*">//
+s/<a href="bibliography.html#[a-zA-Z0-9\.]*">//
+s/<a href="compatibility.html#[a-zA-Z0-9\.]*">//
+s/<a href="configuration.html#[a-zA-Z0-9\.]*">//
+s/<a href="contents.html#[a-zA-Z0-9\.]*">//
+s/<a href="debugging.html#[a-zA-Z0-9\.]*">//
+s/<a href="exportlaws.html#[a-zA-Z0-9\.]*">//
+s/<a href="glossary.html#[a-zA-Z0-9\.]*">//
+s/<a href="index.html#[a-zA-Z0-9\.]*">//
+s/<a href="overview.html#[a-zA-Z0-9\.]*">//
+s/<a href="roadmap.html#[a-zA-Z0-9\.]*">//
+s/<a href="testbed.html#[a-zA-Z0-9\.]*">//
+s/<a href="setup.html#[a-zA-Z0-9\.]*">//
+# pointer to head of doc
+s/<a href="DES.html">//
+s/<a href="RFCs.html">//
+s/<a href="WWWref.html">//
+s/<a href="bibliography.html">//
+s/<a href="compatibility.html">//
+s/<a href="configuration.html">//
+s/<a href="contents.html">//
+s/<a href="debugging.html">//
+s/<a href="exportlaws.html">//
+s/<a href="glossary.html">//
+s/<a href="index.html">//
+s/<a href="overview.html">//
+s/<a href="roadmap.html">//
+s/<a href="testbed.html">//
+s/<a href="setup.html">//
+# xref to non-HTML files
+s/<a href="standards">//
+s/<a href="impl.notes">//
+s/<a href="prob.report">//
diff --git a/doc/web.html b/doc/web.html
new file mode 100644
index 000000000..0c084d289
--- /dev/null
+++ b/doc/web.html
@@ -0,0 +1,749 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
+<HTML>
+<HEAD>
+<TITLE>Introduction to FreeS/WAN</TITLE>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-8859-1">
+<STYLE TYPE="text/css"><!--
+BODY { font-family: serif }
+H1 { font-family: sans-serif }
+H2 { font-family: sans-serif }
+H3 { font-family: sans-serif }
+H4 { font-family: sans-serif }
+H5 { font-family: sans-serif }
+H6 { font-family: sans-serif }
+SUB { font-size: smaller }
+SUP { font-size: smaller }
+PRE { font-family: monospace }
+--></STYLE>
+</HEAD>
+<BODY>
+<A HREF="toc.html">Contents</A>
+<A HREF="mail.html">Previous</A>
+<A HREF="glossary.html">Next</A>
+<HR>
+<H1><A name="weblink">Web links</A></H1>
+<H2><A name="freeswan">The Linux FreeS/WAN Project</A></H2>
+<P>The main project web site is<A href="http://www.freeswan.org/">
+ www.freeswan.org</A>.</P>
+<P>Links to other project-related<A href="intro.html#sites"> sites</A>
+ are provided in our introduction section.</P>
+<H3><A name="patch">Add-ons and patches for FreeS/WAN</A></H3>
+<P>Some user-contributed patches have been integrated into the FreeS/WAN
+ distribution. For a variety of reasons, those listed below have not.</P>
+<P>Note that not all patches are a good idea.</P>
+<UL>
+<LI>There are a number of &quot;features&quot; of IPsec which we do not implement
+ because they reduce security. See this<A href="compat.html#dropped">
+ discussion</A>. We do not recommend using patches that implement these.
+ One example is aggressive mode.</LI>
+<LI>We do not recommend adding &quot;features&quot; of any sort unless they are
+ clearly necessary, or at least have clear benefits. For example,
+ FreeS/WAN would not become more secure if it offerred a choice of 14
+ ciphers. If even one was flawed, it would certainly become less secure
+ for anyone using that cipher. Even with 14 wonderful ciphers, it would
+ be harder to maintain and administer, hence more vulnerable to various
+ human errors.</LI>
+</UL>
+<P>This is not to say that patches are necessarily bad, only that using
+ them requires some deliberation. For example, there might be perfectly
+ good reasons to add a specific cipher in your application: perhaps GOST
+ to comply with government standards in Eastern Europe, or AES for
+ performance benefits.</P>
+<H4>Current patches</H4>
+<P>Patches believed current::</P>
+<UL>
+<LI>patches for<A href="http://www.strongsec.com/freeswan/"> X.509
+ certificate support</A>, also available from a<A href="http://www.twi.ch/~sna/strongsec/freeswan/">
+ mirror site</A></LI>
+<LI>patches to add<A href="http://www.irrigacion.gov.ar/juanjo/ipsec">
+ AES and other ciphers</A>. There is preliminary data indicating AES
+ gives a substantial<A href="performance.html#perf.more"> performance
+ gain</A>.</LI>
+</UL>
+<P>There is also one add-on that takes the form of a modified FreeS/WAN
+ distribution, rather than just patches to the standard distribution:</P>
+<UL>
+<LI><A href="http://www.ipv6.iabg.de/downloadframe/index.html">IPv6
+ support</A></LI>
+</UL>
+<P>Before using any of the above,, check the<A href="mail.html"> mailing
+ lists</A> for news of newer versions and to see whether they have been
+ incorporated into more recent versions of FreeS/WAN.</P>
+<H4>Older patches</H4>
+<UL>
+<LI><A href="http://sources.colubris.com/en/projects/FreeSWAN/">hardware
+ acceleration</A></LI>
+<LI>a<A href="http://tzukanov.narod.ru/"> series</A> of patches that
+<UL>
+<LI>provide GOST, a Russian gov't. standard cipher, in MMX assembler</LI>
+<LI>add GOST to OpenSSL</LI>
+<LI>add GOST to the International kernel patch</LI>
+<LI>let FreeS/WAN use International kernel patch ciphers</LI>
+</UL>
+</LI>
+<LI>Neil Dunbar's patches for<A href="ftp://hplose.hpl.hp.com/pub/nd/pluto-openssl.tar.gz">
+ certificate support</A>, using code from<A href="http://www.openssl.org">
+ Open SSL</A>.</LI>
+<LI>Luc Lanthier's<A href="ftp://ftp.netwinder.org/users/f/firesoul/">
+ patches</A> for<A href="glossary.html#PKIX"> PKIX</A> support.</LI>
+<LI><A href="ftp://ftp.heise.de/pub/ct/listings/9916-180.tgz">patches</A>
+ to add<A href="glossary.html#blowfish"> Blowfish</A>,<A href="glossary.html#IDEA">
+ IDEA</A> and<A href="glossary.html#CAST128"> CAST-128</A> to FreeS/WAN</LI>
+<LI>patches for FreeS/WAN 1.3, Pluto support for<A href="http://alcatraz.webcriminals.com/~bastiaan/ipsec/">
+ external authentication</A>, for example with a smartcard or SKEYID.</LI>
+<LI><A href="http://www.zengl.net/freeswan/download/">patches and
+ utilities</A> for using FreeS/WAN with PGPnet</LI>
+<LI><A href="http://www.freelith.com/lithworks/crypto/freeswan_patch.htm">
+Blowfish encryption and Tiger hash</A></LI>
+<LI><A href="http://www.cendio.se/~bellman/aggressive-pluto.snap.tar.gz">
+patches</A> for aggressive mode support</LI>
+</UL>
+<P>These patches are for older versions of FreeS/WAN and will likely not
+ work with the current version. Older versions of FreeS/WAN may be
+ available on some of the<A href="intro.html#sites"> distribution sites</A>
+, but we recommend using the current release.</P>
+<H4><A name="VPN.masq">VPN masquerade patches</A></H4>
+<P>Finally, there are some patches to other code that may be useful with
+ FreeS/WAN:</P>
+<UL>
+<LI>a<A href="ftp://ftp.rubyriver.com/pub/jhardin/masquerade/ip_masq_vpn.html">
+ patch</A> to make IPsec, PPTP and SSH VPNs work through a Linux
+ firewall with<A href="glossary.html#masq"> IP masquerade</A>.</LI>
+<LI><A href="http://www.linuxdoc.org/HOWTO/VPN-Masquerade-HOWTO.html">
+Linux VPN Masquerade HOWTO</A></LI>
+</UL>
+<P>Note that this is not required if the same machine does IPsec and
+ masquerading, only if you want a to locate your IPsec gateway on a
+ masqueraded network. See our<A href="firewall.html#NAT"> firewalls</A>
+ document for discussion of why this is problematic.</P>
+<P>At last report, this patch could not co-exist with FreeS/WAN on the
+ same machine.</P>
+<H3><A name="dist">Distributions including FreeS/WAN</A></H3>
+<P>The introductory section of our document set lists several<A href="intro.html#distwith">
+ Linux distributions</A> which include FreeS/WAN.</P>
+<H3><A name="used">Things FreeS/WAN uses or could use</A></H3>
+<UL>
+<LI><A href="http://openpgp.net/random">/dev/random</A> support page,
+ discussion of and code for the Linux<A href="glossary.html#random">
+ random number driver</A>. Out-of-date when we last checked (January
+ 2000), but still useful.</LI>
+<LI>other programs related to random numbers:
+<UL>
+<LI><A href="http://www.mindrot.org/audio-entropyd.html">audio entropy
+ daemon</A> to gather noise from a sound card and feed it into
+ /dev/random</LI>
+<LI>an<A href="http://www.lothar.com/tech/crypto/"> entropy-gathering
+ daemon</A></LI>
+<LI>a driver for the random number generator in recent<A href="http://sourceforge.net/projects/gkernel/">
+ Intel chipsets</A>. This driver is included as standard in 2.4 kernels.</LI>
+</UL>
+</LI>
+<LI>a Linux<A href="http://www.marko.net/l2tp/"> L2TP Daemon</A> which
+ might be useful for communicating with Windows 2000 which builds L2TP
+ tunnels over its IPsec connections</LI>
+<LI>to use opportunistic encryption, you need a recent version of<A href="glossary.html#BIND">
+ BIND</A>. You can get one from the<A href="http://www.isc.org">
+ Internet Software Consortium</A> who maintain BIND.</LI>
+</UL>
+<H3><A name="alternatives">Other approaches to VPNs for Linux</A></H3>
+<UL>
+<LI>other Linux<A href="#linuxipsec"> IPsec implementations</A></LI>
+<LI><A href="http://www.tik.ee.ethz.ch/~skip/">ENskip</A>, a free
+ implementation of Sun's<A href="glossary.html#SKIP"> SKIP</A> protocol</LI>
+<LI><A href="http://sunsite.auc.dk/vpnd/">vpnd</A>, a non-IPsec VPN
+ daemon for Linux which creates tunnels using<A href="glossary.html#Blowfish">
+ Blowfish</A> encryption</LI>
+<LI><A href="http://www.winton.org.uk/zebedee/">Zebedee</A>, a simple
+ GPLd tunnel-building program with Linux and Win32 versions. The name is
+ from<STRONG> Z</STRONG>lib compression,<STRONG> B</STRONG>lowfish
+ encryption and<STRONG> D</STRONG>iffie-Hellman key exchange.</LI>
+<LI>There are at least two PPTP implementations for Linux
+<UL>
+<LI>Moreton Bay's<A href="http://www.moretonbay.com/vpn/pptp.html">
+ PoPToP</A></LI>
+<LI><A href="http://cag.lcs.mit.edu/~cananian/Projects/PPTP/">PPTP-Linux</A>
+</LI>
+</UL>
+</LI>
+<LI><A href="http://sites.inka.de/sites/bigred/devel/cipe.html">CIPE</A>
+ (crypto IP encapsulation) project, using their own lightweight protocol
+ to encrypt between routers</LI>
+<LI><A href="http://tinc.nl.linux.org/">tinc</A>, a VPN Daemon</LI>
+</UL>
+<P>There is a list of<A href="http://www.securityportal.com/lskb/10000000/kben10000005.html">
+ Linux VPN</A> software in the<A href="http://www.securityportal.com/lskb/kben00000001.html">
+ Linux Security Knowledge Base</A>.</P>
+<H2><A name="ipsec.link">The IPsec Protocols</A></H2>
+<H3><A name="general">General IPsec or VPN information</A></H3>
+<UL>
+<LI>The<A href="http://www.vpnc.org"> VPN Consortium</A> is a group for
+ vendors of IPsec products. Among other things, they have a good
+ collection of<A href="http://www.vpnc.org/white-papers.html"> IPsec
+ white papers</A>.</LI>
+<LI>A VPN mailing list with a<A href="http://kubarb.phsx.ukans.edu/~tbird/vpn.html">
+ home page</A>, a FAQ, some product comparisons, and many links.</LI>
+<LI><A href="http://www.opus1.com/vpn/index.html">VPN pointer page</A></LI>
+<LI>a<A href="http://www.epm.ornl.gov/~dunigan/vpn.html"> collection</A>
+ of VPN links, and some explanation</LI>
+</UL>
+<H3><A name="overview">IPsec overview documents or slide sets</A></H3>
+<UL>
+<LI>the FreeS/WAN<A href="ipsec.html"> document section</A> on these
+ protocols</LI>
+</UL>
+<H3><A name="otherlang">IPsec information in languages other than
+ English</A></H3>
+<UL>
+<LI><A href="http://www.imib.med.tu-dresden.de/imib/Internet/Literatur/ipsec-docu.html">
+German</A></LI>
+<LI><A href="http://www.kame.net/index-j.html">Japanese</A></LI>
+<LI>Feczak Szabolcs' thesis in<A href="http://feczo.koli.kando.hu/vpn/">
+ Hungarian</A></LI>
+<LI>Davide Cerri's thesis and some presentation slides<A href="http://www.linux.it/~davide/doc/">
+ Italian</A></LI>
+</UL>
+<H3><A name="RFCs1">RFCs and other reference documents</A></H3>
+<UL>
+<LI><A href="rfc.html">Our document</A> listing the RFCs relevant to
+ Linux FreeS/WAN and giving various ways of obtaining both RFCs and
+ Internet Drafts.</LI>
+<LI><A href="http://www.vpnc.org/vpn-standards.html">VPN Standards</A>
+ page maintained by<A href="glossary.html#VPNC"> VPNC</A>. This covers
+ both RFCs and Drafts, and classifies them in a fairly helpful way.</LI>
+<LI><A href="http://www.rfc-editor.org">RFC archive</A></LI>
+<LI><A href="http://www.ietf.org/ids.by.wg/ipsec.html">Internet Drafts</A>
+ related to IPsec</LI>
+<LI>US government<A href="http://www.itl.nist.gov/div897/pubs"> site</A>
+ with their<A href="glossary.html#FIPS"> FIPS</A> standards</LI>
+<LI>Archives of the ipsec@tis.com mailing list where discussion of
+ drafts takes place.
+<UL>
+<LI><A href="http://www.sandelman.ottawa.on.ca/ipsec">Eastern Canada</A></LI>
+<LI><A href="http://www.vpnc.org/ietf-ipsec">California</A>.</LI>
+</UL>
+</LI>
+</UL>
+<H3><A name="analysis">Analysis and critiques of IPsec protocols</A></H3>
+<UL>
+<LI>Counterpane's<A href="http://www.counterpane.com/ipsec.pdf">
+ evaluation</A> of the protocols</LI>
+<LI>Simpson's<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/1999/06/msg00319.html">
+ IKE Considered Dangerous</A> paper. Note that this is a link to an
+ archive of our mailing list. There are several replies in addition to
+ the paper itself.</LI>
+<LI>Fate Labs<A href="http://www.fatelabs.com/loki-vpn.pdf"> Virual
+ Private Problems: the Broken Dream</A></LI>
+<LI>Catherine Meadows' paper<CITE> Analysis of the Internet Key Exchange
+ Protocol Using the NRL Protocol Analyzer</CITE>, in<A href="http://chacs.nrl.navy.mil/publications/CHACS/1999/1999meadows-IEEE99.pdf">
+ PDF</A> or<A href="http://chacs.nrl.navy.mil/publications/CHACS/1999/1999meadows-IEEE99.ps">
+ Postscript</A>.</LI>
+<LI>Perlman and Kaufmnan
+<UL>
+<LI><A href="http://snoopy.seas.smu.edu/ee8392_summer01/week7/perlman2.pdf">
+Key Exchange in IPsec</A></LI>
+<LI>a newer<A href="http://sec.femto.org/wetice-2001/papers/radia-paper.pdf">
+ PDF paper</A>,<CITE> Analysis of the IPsec Key Exchange Standard</CITE>
+.</LI>
+</UL>
+</LI>
+<LI>Bellovin's<A href="http://www.research.att.com/~smb/papers/index.html">
+ papers</A> page including his:
+<UL>
+<LI><CITE>Security Problems in the TCP/IP Protocol Suite</CITE> (1989)</LI>
+<LI><CITE>Problem Areas for the IP Security Protocols</CITE> (1996)</LI>
+<LI><CITE>Probable Plaintext Cryptanalysis of the IP Security Protocols</CITE>
+ (1997)</LI>
+</UL>
+</LI>
+<LI>An<A href="http://www.lounge.org/ike_doi_errata.html"> errata list</A>
+ for the IPsec RFCs.</LI>
+</UL>
+<H3><A name="IP.background">Background information on IP</A></H3>
+<UL>
+<LI>An<A href="http://ipprimer.windsorcs.com/"> IP tutorial</A> that
+ seems to be written mainly for Netware or Microsoft LAN admins entering
+ a new world</LI>
+<LI><A href="http://www.iana.org">IANA</A>, Internet Assigned Numbers
+ Authority</LI>
+<LI><A href="http://public.pacbell.net/dedicated/cidr.html">CIDR</A>,
+ Classless Inter-Domain Routing</LI>
+<LI>Also see our<A href="biblio.html"> bibliography</A></LI>
+</UL>
+<H2><A name="implement">IPsec Implementations</A></H2>
+<H3><A name="linuxprod">Linux products</A></H3>
+<P>Vendors using FreeS/WAN in turnkey firewall or VPN products are
+ listed in our<A href="intro.html#turnkey"> introduction</A>.</P>
+<P>Other vendors have Linux IPsec products which, as far as we know, do
+ not use FreeS/WAN</P>
+<UL>
+<LI><A href="http://www.redcreek.com/products/shareware.html">Redcreek</A>
+ provide an open source Linux driver for their PCI hardware VPN card.
+ This card has a 100 Mbit Ethernet port, an Intel 960 CPU plus more
+ specialised crypto chips, and claimed encryption performance of 45
+ Mbit/sec. The PC sees it as an Ethernet board.</LI>
+<LI><A href="http://linuxtoday.com/stories/8428.html?nn">Paktronix</A>
+ offer a Linux-based VPN with hardware encryption</LI>
+<LI><A href="http://www.watchguard.com/">Watchguard</A> use Linux in
+ their Firebox product.</LI>
+<LI><A href="http://www.entrust.com">Entrust</A> offer a developers'
+ toolkit for using their<A href="glossary.html#PKI"> PKI</A> for IPsec
+ authentication</LI>
+<LI>According to a report on our mailing list,<A href="http://www.axent.com">
+ Axent</A> have a Linux version of their product.</LI>
+</UL>
+<H3><A name="router">IPsec in router products</A></H3>
+<P>All the major router vendors support IPsec, at least in some models.</P>
+<UL>
+<LI><A href="http://www.cisco.com/warp/public/707/16.html">Cisco</A>
+ IPsec information</LI>
+<LI>Ascend, now part of<A href="http://www.lucent.com/"> Lucent</A>,
+ have some IPsec-based products</LI>
+<LI><A href="http://www.nortelnetworks.com/">Bay Networks</A>, now part
+ of Nortel, use IPsec in their Contivity switch product line</LI>
+<LI><A href="http://www.3com.com/products/enterprise.html">3Com</A> have
+ a number of VPN products, some using IPsec</LI>
+</UL>
+<H3><A name="fw.web">IPsec in firewall products</A></H3>
+<P>Many firewall vendors offer IPsec, either as a standard part of their
+ product, or an optional extra. A few we know about are:</P>
+<UL>
+<LI><A href="http://www.borderware.com/">Borderware</A></LI>
+<LI><A href="http://www.ashleylaurent.com/vpn/ipsec_vpn.htm">Ashley
+ Laurent</A></LI>
+<LI><A href="http://www.watchguard.com">Watchguard</A></LI>
+<LI><A href="http://www.fx.dk/firewall/ipsec.html">Injoy</A> for OS/2</LI>
+</UL>
+<P>Vendors using FreeS/WAN in turnkey firewall products are listed in
+ our<A href="intro.html#turnkey"> introduction</A>.</P>
+<H3><A name="ipsecos">Operating systems with IPsec support</A></H3>
+<P>All the major open source operating systems support IPsec. See below
+ for details on<A href="#BSD"> BSD-derived</A> Unix variants.</P>
+<P>Among commercial OS vendors, IPsec players include:</P>
+<UL>
+<LI><A href="http://msdn.microsoft.com/isapi/msdnlib.idc?theURL=/library/backgrnd/html/msdn_ip_security.htm">
+Microsoft</A> have put IPsec in their Windows 2000 and XP products</LI>
+<LI><A href="http://www.s390.ibm.com/stories/1999/os390v2r8_pr.html">IBM</A>
+ announce a release of OS390 with IPsec support via a crypto
+ co-processor</LI>
+<LI><A href="http://www.sun.com/solaris/ds/ds-security/ds-security.pdf">
+Sun</A> include IPsec in Solaris 8</LI>
+<LI><A href="http://www.hp.com/security/products/extranet-security.html">
+Hewlett Packard</A> offer IPsec for their Unix machines</LI>
+<LI>Certicom have IPsec available for the<A href="http://www.certicom.com/products/movian/movianvpn_tech.html">
+ Palm</A>.</LI>
+<LI>There were reports before the release that Apple's Mac OS X would
+ have IPsec support built in, but it did not seem to be there when we
+ last checked. If you find, it please let us know via the<A href="mail.html">
+ mailing list</A>.</LI>
+</UL>
+<H3><A NAME="29_3_5">IPsec on network cards</A></H3>
+<P>Network cards with built-in IPsec acceleration are available from at
+ least Intel, 3Com and Redcreek.</P>
+<H3><A name="opensource">Open source IPsec implementations</A></H3>
+<H4><A name="linuxipsec">Other Linux IPsec implementations</A></H4>
+<P>We like to think of FreeS/WAN as<EM> the</EM> Linux IPsec
+ implementation, but it is not the only one. Others we know of are:</P>
+<UL>
+<LI><A href="http://www.enst.fr/~beyssac/pipsec/">pipsecd</A>, a
+ lightweight implementation of IPsec for Linux. Does not require kernel
+ recompilation.</LI>
+<LI>Petr Novak's<A href="ftp://ftp.eunet.cz/icz/ipnsec/"> ipnsec</A>,
+ based on the OpenBSD IPsec code and using<A href="glossary.html#photuris">
+ Photuris</A> for key management</LI>
+<LI>A now defunct project at<A href="http://www.cs.arizona.edu/security/hpcc-blue/linux.html">
+ U of Arizona</A> (export controlled)</LI>
+<LI><A href="http://snad.ncsl.nist.gov/cerberus">NIST Cerebus</A>
+ (export controlled)</LI>
+</UL>
+<H4><A name="BSD">IPsec for BSD Unix</A></H4>
+<UL>
+<LI><A href="http://www.kame.net/project-overview.html">KAME</A>,
+ several large Japanese companies co-operating on IPv6 and IPsec</LI>
+<LI><A href="http://web.mit.edu/network/isakmp">US Naval Research Lab</A>
+ implementation of IPv6 and of IPsec for IPv4 (export controlled)</LI>
+<LI><A href="http://www.openbsd.org">OpenBSD</A> includes IPsec as a
+ standard part of the distribution</LI>
+<LI><A href="http://www.r4k.net/ipsec">IPsec for FreeBSD</A></LI>
+<LI>a<A href="http://www.netbsd.org/Documentation/network/ipsec/"> FAQ</A>
+ on NetBSD's IPsec implementation</LI>
+</UL>
+<H4><A name="misc">IPsec for other systems</A></H4>
+<UL>
+<LI><A href="http://www.tcm.hut.fi/Tutkimus/IPSEC/">Helsinki U of
+ Technolgy</A> have implemented IPsec for Solaris, Java and Macintosh</LI>
+</UL>
+<H3><A name="interop.web">Interoperability</A></H3>
+<P>The IPsec protocols are designed so that different implementations
+ should be able to work together. As they say &quot;the devil is in the
+ details&quot;. IPsec has a lot of details, but considerable success has been
+ achieved.</P>
+<H4><A name="result">Interoperability results</A></H4>
+<P>Linux FreeS/WAN has been tested for interoperability with many other
+ IPsec implementations. Results to date are in our<A href="interop.html">
+ interoperability</A> section.</P>
+<P>Various other sites have information on interoperability between
+ various IPsec implementations:</P>
+<UL>
+<LI><A href="http://www.opus1.com/vpn/atl99display.html">interop results</A>
+ from a bakeoff in Atlanta, September 1999.</LI>
+<LI>a French company, HSC's,<A href="http://www.hsc.fr/ressources/presentations/ipsec99/index.html.en">
+ interoperability</A> test data covers FreeS/WAN, Open BSD, KAME, Linux
+ pipsecd, Checkpoint, Red Creek Ravlin, and Cisco IOS</LI>
+<LI><A href="http://www.icsa.net/">ICSA</A> offer certification programs
+ for various security-related products. See their list of<A href="http://www.icsa.net/html/communities/ipsec/certification/certified_products/index.shtml">
+ certified IPsec</A> products. Linux FreeS/WAN is not currently on that
+ list, but several products with which we interoperate are.</LI>
+<LI>VPNC have a page on why they are not yet doing<A href="http://www.vpnc.org/interop.html">
+ interoperability</A> testing and a page on the<A href="http://www.vpnc.org/conformance.html">
+ spec conformance</A> testing that they are doing</LI>
+<LI>a<A href="http://www.commweb.com/article/COM20000912S0009"> review</A>
+ comparing a dozen commercial IPsec implemetations. Unfortunately, the
+ reviewers did not look at Open Source implementations such as FreeS/WAN
+ or OpenBSD.</LI>
+<LI><A href="http://www.tanu.org/~sakane/doc/public/report-ike-interop0007.html">
+results</A> from interoperability tests at a conference. FreeS/WAN was
+ not tested there.</LI>
+<LI>test results from the<A href="http://www.hsc.fr/ressources/veille/ipsec/ipsec2000/">
+ IPSEC 2000</A> conference</LI>
+</UL>
+<H4><A name="test1">Interoperability test sites</A></H4>
+<UL>
+<LI><A href="http://www.tahi.org/">TAHI</A>, a Japanese IPv6 testing
+ project with free IPsec validation software</LI>
+<LI><A href="http://ipsec-wit.antd.nist.gov">National Institute of
+ Standards and Technology</A></LI>
+<LI><A href="http://isakmp-test.ssh.fi/">SSH Communications Security</A></LI>
+</UL>
+<H2><A name="linux.link">Linux links</A></H2>
+<H3><A name="linux.basic">Basic and tutorial Linux information</A></H3>
+<UL>
+<LI>Linux<A href="http://linuxcentral.com/linux/LDP/LDP/gs/gs.html">
+ Getting Started</A> HOWTO document</LI>
+<LI>A getting started guide from the<A href="http://darkwing.uoregon.edu/~cchome/linuxgettingstarted.html">
+ U of Oregon</A></LI>
+<LI>A large<A href="http://www.herring.org/techie.html"> link collection</A>
+ which includes a lot of introductory and tutorial material on Unix,
+ Linux, the net, . . .</LI>
+</UL>
+<H3><A name="general">General Linux sites</A></H3>
+<UL>
+<LI><A href="http://www.freshmeat.net">Freshmeat</A> Linux news</LI>
+<LI><A href="http://slashdot.org">Slashdot</A> &quot;News for Nerds&quot;</LI>
+<LI><A href="http://www.linux.org">Linux Online</A></LI>
+<LI><A href="http://www.linuxhq.com">Linux HQ</A></LI>
+<LI><A href="http://www.tux.org">tux.org</A></LI>
+</UL>
+<H3><A name="docs.ldp">Documentation</A></H3>
+<P>Nearly any Linux documentation you are likely to want can be found at
+ the<A href="http://metalab.unc.edu/LDP"> Linux Documentation Project</A>
+ or LDP.</P>
+<UL>
+<LI><A href="http://metalab.unc.edu/LDP/HOWTO/META-FAQ.html">Meta-FAQ</A>
+ guide to Linux information sources</LI>
+<LI>The LDP's HowTo documents are a standard Linux reference. See this<A href="http://www.linuxdoc.org/docs.html#howto">
+ list</A>. Documents there most relevant to a FreeS/WAN gateway are:
+<UL>
+<LI><A href="http://metalab.unc.edu/LDP/HOWTO/Kernel-HOWTO.html">Kernel
+ HOWTO</A></LI>
+<LI><A href="http://metalab.unc.edu/LDP/HOWTO/Networking-Overview-HOWTO.html">
+Networking Overview HOWTO</A></LI>
+<LI><A href="http://metalab.unc.edu/LDP/HOWTO/Security-HOWTO.html">
+Security HOWTO</A></LI>
+</UL>
+</LI>
+<LI>The LDP do a series of Guides, book-sized publications with more
+ detail (and often more &quot;why do it this way?&quot;) than the HowTos. See this<A
+href="http://www.linuxdoc.org/guides.html"> list</A>. Documents there
+ most relevant to a FreeS/WAN gateway are:
+<UL>
+<LI><A href="http://www.tml.hut.fi/~viu/linux/sag/">System
+ Administrator's Guide</A></LI>
+<LI><A href="http://www.linuxdoc.org/LDP/nag2/index.html">Network
+ Adminstrator's Guide</A></LI>
+<LI><A href="http://www.seifried.org/lasg/">Linux Administrator's
+ Security Guide</A></LI>
+</UL>
+</LI>
+</UL>
+<P>You may not need to go to the LDP to get this material. Most Linux
+ distributions include the HowTos on their CDs and several include the
+ Guides as well. Also, most of the Guides and some collections of HowTos
+ are available in book form from various publishers.</P>
+<P>Much of the LDP material is also available in languages other than
+ English. See this<A href="http://www.linuxdoc.org/links/nenglish.html">
+ LDP page</A>.</P>
+<H3><A name="advroute.web">Advanced routing</A></H3>
+<P>The Linux IP stack has some new features in 2.4 kernels. Some HowTos
+ have been written:</P>
+<UL>
+<LI>several HowTos for the<A href="http://netfilter.samba.org/unreliable-guides/">
+ netfilter</A> firewall code in newer kernels</LI>
+<LI><A href="http://www.ds9a.nl/2.4Networking/HOWTO//cvs/2.4routing/output/2.4networking.html">
+2.4 networking</A> HowTo</LI>
+<LI><A href="http://www.ds9a.nl/2.4Networking/HOWTO//cvs/2.4routing/output/2.4routing.html">
+2.4 routing</A> HowTo</LI>
+</UL>
+<H3><A name="linsec">Security for Linux</A></H3>
+<P>See also the<A href="#docs.ldp"> LDP material</A> above.</P>
+<UL>
+<LI><A href="http://www.ecst.csuchico.edu/~dranch/LINUX/index-linux.html#trinityos">
+Trinity OS guide to setting up Linux</A></LI>
+<LI><A href="http://www.deter.com/unix">Unix security</A> page</LI>
+<LI><A href="http://linux01.gwdg.de/~alatham/">PPDD</A> encrypting
+ filesystem</LI>
+<LI><A href="http://EncryptionHOWTO.sourceforge.net/">Linux Encryption
+ HowTo</A> (outdated when last checked, had an Oct 2000 revision date in
+ March 2002)</LI>
+</UL>
+<H3><A name="firewall.linux">Linux firewalls</A></H3>
+<P>Our<A href="firewall.html"> FreeS/WAN and firewalls</A> document
+ includes links to several sets of<A href="firewall.html#examplefw">
+ scripts</A> known to work with FreeS/WAN.</P>
+<P>Other information sources:</P>
+<UL>
+<LI><A href="http://ipmasq.cjb.net/">IP Masquerade resource page</A></LI>
+<LI><A href="http://netfilter.samba.org/unreliable-guides/">netfilter</A>
+ firewall code in 2.4 kernels</LI>
+<LI>Our list of general<A href="#firewall.web"> firewall references</A>
+ on the web</LI>
+<LI><A href="http://users.dhp.com/~whisper/mason/">Mason</A>, a tool for
+ automatically configuring Linux firewalls</LI>
+<LI>the web cache software<A href="http://www.squid-cache.org/"> squid</A>
+ and<A href="http://www.squidguard.org/"> squidguard</A> which turns
+ Squid into a filtering web proxy</LI>
+</UL>
+<H3><A name="linux.misc">Miscellaneous Linux information</A></H3>
+<UL>
+<LI><A href="http://lwn.net/current/dists.php3">Linux distribution
+ vendors</A></LI>
+<LI><A href="http://www.linux.org/groups/">Linux User Groups</A></LI>
+</UL>
+<H2><A name="crypto.link">Crypto and security links</A></H2>
+<H3><A name="security">Crypto and security resources</A></H3>
+<H4><A name="std.links">The standard link collections</A></H4>
+<P>Two enormous collections of links, each the standard reference in its
+ area:</P>
+<DL>
+<DT>Gene Spafford's<A href="http://www.cerias.purdue.edu/coast/hotlist/">
+ COAST hotlist</A></DT>
+<DD>Computer and network security.</DD>
+<DT>Peter Gutmann's<A href="http://www.cs.auckland.ac.nz/~pgut001/links.html">
+ Encryption and Security-related Resources</A></DT>
+<DD>Cryptography.</DD>
+</DL>
+<H4><A name="FAQ">Frequently Asked Question (FAQ) documents</A></H4>
+<UL>
+<LI><A href="http://www.faqs.org/faqs/cryptography-faq/">Cryptography
+ FAQ</A></LI>
+<LI><A href="http://www.interhack.net/pubs/fwfaq">Firewall FAQ</A></LI>
+<LI><A href="http://www.whitefang.com/sup/secure-faq.html">Secure Unix
+ Programming FAQ</A></LI>
+<LI>FAQs for specific programs are listed in the<A href="#tools"> tools</A>
+ section below.</LI>
+</UL>
+<H4><A name="cryptover">Tutorials</A></H4>
+<UL>
+<LI>Gary Kessler's<A href="http://www.garykessler.net/library/crypto.html">
+ Overview of Cryptography</A></LI>
+<LI>Terry Ritter's<A href="http://www.ciphersbyritter.com/LEARNING.HTM">
+ introduction</A></LI>
+<LI>Peter Gutman's<A href="http://www.cs.auckland.ac.nz/~pgut001/tutorial/index.html">
+ cryptography</A> tutorial (500 slides in PDF format)</LI>
+<LI>Amir Herzberg of IBM's sildes for his course<A href="http://www.hrl.il.ibm.com/mpay/course.html">
+ Introduction to Cryptography and Electronic Commerce</A></LI>
+<LI>the<A href="http://www.gnupg.org/gph/en/manual/c173.html"> concepts
+ section</A> of the<A href="glossary.html#GPG"> GNU Privacy Guard</A>
+ documentation</LI>
+<LI>Bruce Schneier's self-study<A href="http://www.counterpane.com/self-study.html">
+ cryptanalysis</A> course</LI>
+</UL>
+<P>See also the<A href="#interesting"> interesting papers</A> section
+ below.</P>
+<H4><A name="standards">Crypto and security standards</A></H4>
+<UL>
+<LI><A href="http://csrc.nist.gov/cc">Common Criteria</A>, new
+ international computer and network security standards to replace the
+ &quot;Rainbow&quot; series</LI>
+<LI>AES<A href="http://csrc.nist.gov/encryption/aes/aes_home.htm">
+ Advanced Encryption Standard</A> which will replace DES</LI>
+<LI><A href="http://grouper.ieee.org/groups/1363">IEEE P-1363 public key
+ standard</A></LI>
+<LI>our collection of links for the<A href="#ipsec.link"> IPsec</A>
+ standards</LI>
+<LI>history of<A href="http://www.visi.com/crypto/evalhist/index.html">
+ formal evaluation</A> of security policies and implementation</LI>
+</UL>
+<H4><A name="quotes">Crypto quotes</A></H4>
+<P>There are several collections of cryptographic quotes on the net:</P>
+<UL>
+<LI><A href="http://www.eff.org/pub/EFF/quotes.eff">the EFF</A></LI>
+<LI><A href="http://www.samsimpson.com/cquotes.php">Sam Simpson</A></LI>
+<LI><A href="http://www.amk.ca/quotations/cryptography/page-1.html">AM
+ Kutchling</A></LI>
+</UL>
+<H3><A name="policy">Cryptography law and policy</A></H3>
+<H4><A name="legal">Surveys of crypto law</A></H4>
+<UL>
+<LI>International survey of<A href="http://cwis.kub.nl/~FRW/PEOPLE/koops/lawsurvy.htm">
+ crypto law</A>.</LI>
+<LI>International survey of<A href="http://rechten.kub.nl/simone/ds-lawsu.htm">
+ digital signature law</A></LI>
+</UL>
+<H4><A name="oppose">Organisations opposing crypto restrictions</A></H4>
+<UL>
+<LI>The<A href="glossary.html#EFF"> EFF</A>'s archives on<A href="http://www.eff.org/pub/Privacy/">
+ privacy</A> and<A href="http://www.eff.org/pub/Privacy/ITAR_export/">
+ export control</A>.</LI>
+<LI><A href="http://www.gilc.org">Global Internet Liberty Campaign</A></LI>
+<LI><A href="http://www.cdt.org/crypto">Center for Democracy and
+ Technology</A></LI>
+<LI><A href="http://www.privacyinternational.org/">Privacy International</A>
+, who give out<A href="http://www.bigbrotherawards.org/"> Big Brother
+ Awards</A> to snoopy organisations</LI>
+</UL>
+<H4><A name="other.policy">Other information on crypto policy</A></H4>
+<UL>
+<LI><A href="ftp://ftp.isi.edu/in-notes/rfc1984.txt">RFC 1984</A>, the<A href="glossary.html#IAB">
+ IAB</A> and<A href="glossary.html#IESG"> IESG</A> Statement on
+ Cryptographic Technology and the Internet.</LI>
+<LI>John Young's collection of<A href="http://cryptome.org/"> documents</A>
+ of interest to the cryptography, open government and privacy movements,
+ organized chronologically</LI>
+<LI>AT&amp;T researcher Matt Blaze's Encryption, Privacy and Security<A href="http://www.crypto.com">
+ Resource Page</A></LI>
+<LI>A good<A href="http://cryptome.org/crypto97-ne.htm"> overview</A> of
+ the issues from Australia.</LI>
+</UL>
+<P>See also our documentation section on the<A href="politics.html">
+ history and politics</A> of cryptography.</P>
+<H3><A name="crypto.tech">Cryptography technical information</A></H3>
+<H4><A name="cryptolinks">Collections of crypto links</A></H4>
+<UL>
+<LI><A href="http://www.counterpane.com/hotlist.html">Counterpane</A></LI>
+<LI><A href="http://www.cs.auckland.ac.nz/~pgut001/links.html">Peter
+ Gutman's links</A></LI>
+<LI><A href="http://www.pca.dfn.de/eng/team/ske/pem-dok.html">PKI links</A>
+</LI>
+<LI><A href="http://crypto.yashy.com/www/">Robert Guerra's links</A></LI>
+</UL>
+<H4><A name="papers">Lists of online cryptography papers</A></H4>
+<UL>
+<LI><A href="http://www.counterpane.com/biblio">Counterpane</A></LI>
+<LI><A href="http://www.cryptography.com/resources/papers">
+cryptography.com</A></LI>
+<LI><A href="http://www.cryptosoft.com/html/secpub.htm">Cryptosoft</A></LI>
+</UL>
+<H4><A name="interesting">Particularly interesting papers</A></H4>
+<P>These papers emphasize important issues around the use of
+ cryptography, and the design and management of secure systems.</P>
+<UL>
+<LI><A href="http://www.counterpane.com/keylength.html">Key length
+ requirements for security</A></LI>
+<LI><A href="http://www.cl.cam.ac.uk/users/rja14/wcf.html">Why
+ Cryptosystems Fail</A></LI>
+<LI><A href="http://www.cdt.org/crypto/risks98/">Risks of escrowed
+ encryption</A></LI>
+<LI><A href="http://www.counterpane.com/pitfalls.html">Security pitfalls
+ in cryptography</A></LI>
+<LI><A href="http://www.acm.org/classics/sep95">Reflections on Trusting
+ Trust</A>, Ken Thompson on Trojan horse design</LI>
+<LI><A href="http://www.apache-ssl.org/disclosure.pdf">Security against
+ Compelled Disclosure</A>, how to maintain privacy in the face of legal
+ or other coersion</LI>
+</UL>
+<H3><A name="compsec">Computer and network security</A></H3>
+<H4><A name="seclink">Security links</A></H4>
+<UL>
+<LI><A href="http://www.cs.purdue.edu/coast/hotlist">COAST Hotlist</A></LI>
+<LI>DMOZ open directory project<A href="http://dmoz.org/Computers/Security/">
+ computer security</A> links</LI>
+<LI><A href="http://www-cse.ucsd.edu/users/bsy/sec.html">Bennet Yee</A></LI>
+<LI>Mike Fuhr's<A href="http://www.fuhr.org/~mfuhr/computers/security.html">
+ link collection</A></LI>
+<LI><A href="http://www.networkintrusion.co.uk/">links</A> with an
+ emphasis on intrusion detection</LI>
+</UL>
+<H4><A name="firewall.web">Firewall links</A></H4>
+<UL>
+<LI><A href="http://www.cs.purdue.edu/coast/firewalls">COAST firewalls</A>
+</LI>
+<LI><A href="http://www.zeuros.co.uk">Firewalls Resource page</A></LI>
+</UL>
+<H4><A name="vpn">VPN links</A></H4>
+<UL>
+<LI><A href="http://www.vpnc.org">VPN Consortium</A></LI>
+<LI>First VPN's<A href="http://www.firstvpn.com/research/rhome.html">
+ white paper</A> collection</LI>
+</UL>
+<H4><A name="tools">Security tools</A></H4>
+<UL>
+<LI>PGP -- mail encryption
+<UL>
+<LI><A href="http://www.pgp.com/">PGP Inc.</A> (part of NAI) for
+ commercial versions</LI>
+<LI><A href="http://web.mit.edu/network/pgp.html">MIT</A> distributes
+ the NAI product for non-commercial use</LI>
+<LI><A href="http://www.pgpi.org/">international</A> distribution site</LI>
+<LI><A href="http://gnupg.org">GNU Privacy Guard (GPG)</A></LI>
+<LI><A href="http://www.dk.pgp.net/pgpnet/pgp-faq/">PGP FAQ</A></LI>
+</UL>
+ A message in our mailing list archive has considerable detail on<A href="http://www.sandelman.ottawa.on.ca/linux-ipsec/html/2000/12/msg00029.html">
+ available versions</A> of PGP and on IPsec support in them.
+<P><STRONG>Note:</STRONG> A fairly nasty bug exists in all commercial
+ PGP versions from 5.5 through 6.5.3. If you have one of those,<STRONG>
+ upgrade now</STRONG>.</P>
+</LI>
+<LI>SSH -- secure remote login
+<UL>
+<LI><A href="http://www.ssh.fi">SSH Communications Security</A>, for the
+ original software. It is free for trial, academic and non-commercial
+ use.</LI>
+<LI><A href="http://www.openssh.com/">Open SSH</A>, the Open BSD team's
+ free replacement</LI>
+<LI><A href="http://www.freessh.org/">freessh.org</A>, links to free
+ implementations for many systems</LI>
+<LI><A href="http://www.uni-karlsruhe.de/~ig25/ssh-faq">SSH FAQ</A></LI>
+<LI><A href="http://www.chiark.greenend.org.uk/~sgtatham/putty/">Putty</A>
+, an SSH client for Windows</LI>
+</UL>
+</LI>
+<LI>Tripwire saves message digests of your system files. Re-calculate
+ the digests and compare to saved values to detect any file changes.
+ There are several versions available:
+<UL>
+<LI><A href="http://www.tripwiresecurity.com/">commercial version</A></LI>
+<LI><A href="http://www.tripwire.org/">Open Source</A></LI>
+</UL>
+</LI>
+<LI><A href="http://www.snort.org">Snort</A> and<A href="http://www.lids.org">
+ LIDS</A> are intrusion detection system for Linux</LI>
+<LI><A href="http://www.fish.com/~zen/satan/satan.html">SATAN</A> System
+ Administrators Tool for Analysing Networks</LI>
+<LI><A href="http://www.insecure.org/nmap/">NMAP</A> Network Mapper</LI>
+<LI><A href="ftp://ftp.porcupine.org/pub/security/index.html">Wietse
+ Venema's page</A> with various tools</LI>
+<LI><A href="http://ita.ee.lbl.gov/index.html">Internet Traffic Archive</A>
+, various tools to analyze network traffic, mostly scripts to organise
+ and format tcpdump(8) output for specific purposes</LI>
+<LI><A name="ssmail">ssmail -- sendmail patched to do</A><A href="glossary.html#carpediem">
+ opportunistic encryption</A>
+<UL>
+<LI><A href="http://www.home.aone.net.au/qualcomm/">web page</A> with
+ links to code and to a Usenix paper describing it, in PDF</LI>
+</UL>
+</LI>
+<LI><A href="http://www.openca.org/">Open CA</A> project to develop a
+ freely distributed<A href="glossary.html#CA"> Certification Authority</A>
+ for building a open<A href="glossary.html#PKI"> Public Key
+ Infrastructure</A>.</LI>
+</UL>
+<H3><A name="people">Links to home pages</A></H3>
+<P>David Wagner at Berkeley provides a set of links to<A href="http://www.cs.berkeley.edu/~daw/people/crypto.html">
+ home pages</A> of cryptographers, cypherpunks and computer security
+ people.</P>
+<HR>
+<A HREF="toc.html">Contents</A>
+<A HREF="mail.html">Previous</A>
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