path: root/man/strongswan.conf.5.in

.TH STRONGSWAN.CONF 5 "2010-09-09" "@IPSEC_VERSION@" "strongSwan"
.SH NAME
strongswan.conf \- strongSwan configuration file
.SH DESCRIPTION
While the
.IR ipsec.conf (5)
configuration file is well suited to define IPsec related configuration
parameters, it is not useful for other strongSwan applications to read options
from this file.
The file is hard to parse and only
.I ipsec starter
is capable of doing so. As the number of components of the strongSwan project
is continually growing, a more flexible configuration file was needed, one that
is easy to extend and can be used by all components. With strongSwan 4.2.1
.IR strongswan.conf (5)
was introduced which meets these requirements.

.SH SYNTAX
The format of the strongswan.conf file consists of hierarchical
.B sections
and a list of
.B key/value pairs
in each section. Each section has a name, followed by C-Style curly brackets
defining the section body. Each section body contains a set of subsections
and key/value pairs:
.PP
.EX
	settings := (section|keyvalue)*
	section  := name { settings }
	keyvalue := key = value\\n
.EE
.PP
Values must be terminated by a newline.
.PP
Comments are possible using the \fB#\fP-character, but be careful: The parser
implementation is currently limited and does not like brackets in comments.
.PP
Section names and keys may contain any printable character except:
.PP
.EX
	. { } # \\n \\t space
.EE
.PP
An example file in this format might look like this:
.PP
.EX
	a = b
	section-one {
		somevalue = asdf
		subsection {
			othervalue = xxx
		}
		# yei, a comment
		yetanother = zz
	}
	section-two {
		x = 12
	}
.EE
.PP
Indentation is optional, you may use tabs or spaces.

.SH READING VALUES
Values are accessed using a dot-separated section list and a key.
With reference to the example above, accessing
.B section-one.subsection.othervalue
will return
.BR xxx .

.SH DEFINED KEYS
The following keys are currently defined (using dot notation). The default
value (if any) is listed in brackets after the key.

.SS charon section
.TP
.BR charon.block_threshold " [5]"
Maximum number of half-open IKE_SAs for a single peer IP
.TP
.BR charon.close_ike_on_child_failure " [no]"
Close the IKE_SA if setup of the CHILD_SA along with IKE_AUTH failed
.TP
.BR charon.cookie_threshold " [10]"
Number of half-open IKE_SAs that activate the cookie mechanism
.TP
.BR charon.dns1
.TQ
.BR charon.dns2
DNS servers assigned to peer via configuration payload (CP)
.TP
.BR charon.dos_protection " [yes]"
Enable Denial of Service protection using cookies and aggressiveness checks
.TP
.BR charon.filelog
Section to define file loggers, see LOGGER CONFIGURATION
.TP
.BR charon.flush_auth_cfg " [no]"

.TP
.BR charon.hash_and_url " [no]"
Enable hash and URL support
.TP
.BR charon.ignore_routing_tables
A list of routing tables to be excluded from route lookup
.TP
.BR charon.ikesa_table_segments " [1]"
Number of exclusively locked segments in the hash table
.TP
.BR charon.ikesa_table_size " [1]"
Size of the IKE_SA hash table
.TP
.BR charon.inactivity_close_ike " [no]"
Whether to close IKE_SA if the only CHILD_SA closed due to inactivity
.TP
.BR charon.install_routes " [yes]"
Install routes into a separate routing table for established IPsec tunnels
.TP
.BR charon.install_virtual_ip " [yes]"
Install virtual IP addresses
.TP
.BR charon.keep_alive " [20s]"
NAT keep alive interval
.TP
.BR charon.load
Plugins to load in the IKEv2 daemon charon
.TP
.BR charon.max_packet " [10000]"
Maximum packet size accepted by charon
.TP
.BR charon.multiple_authentication " [yes]"
Enable multiple authentication exchanges (RFC 4739)
.TP
.BR charon.nbns1
.TQ
.BR charon.nbns2
WINS servers assigned to peer via configuration payload (CP)
.TP
.BR charon.process_route " [yes]"
Process RTM_NEWROUTE and RTM_DELROUTE events
.TP
.BR charon.receive_delay " [0]"
Delay for receiving packets, to simulate larger RTT
.TP
.BR charon.receive_delay_response " [yes]"
Delay response messages
.TP
.BR charon.receive_delay_request " [yes]"
Delay request messages
.TP
.BR charon.receive_delay_type " [0]"
Specific IKEv2 message type to delay, 0 for any
.TP
.BR charon.retransmit_base " [1.8]"
Base to use for calculating exponential back off, see IKEv2 RETRANSMISSION
.TP
.BR charon.retransmit_timeout " [4.0]
Timeout in seconds before sending first retransmit
.TP
.BR charon.retransmit_tries " [5]"
Number of times to retransmit a packet before giving up
.TP
.BR charon.reuse_ikesa " [yes]
Initiate CHILD_SA within existing IKE_SAs
.TP
.BR charon.routing_table
Numerical routing table to install routes to
.TP
.BR charon.routing_table_prio
Priority of the routing table
.TP
.BR charon.send_delay " [0]"
Delay for sending packets, to simulate larger RTT
.TP
.BR charon.send_delay_response " [yes]"
Delay response messages
.TP
.BR charon.send_delay_request " [yes]"
Delay request messages
.TP
.BR charon.send_delay_type " [0]"
Specific IKEv2 message type to delay, 0 for any
.TP
.BR charon.send_vendor_id " [no]
Send strongSwan vendor ID payload
.TP
.BR charon.syslog
Section to define syslog loggers, see LOGGER CONFIGURATION
.TP
.BR charon.threads " [16]"
Number of worker threads in charon
.SS charon.plugins subsection
.TP
.BR charon.plugins.android.loglevel " [1]"
Loglevel for logging to Android specific logger
.TP
.BR charon.plugins.attr
Section to specify arbitrary attributes that are assigned to a peer via
configuration payload (CP)
.TP
.BR charon.plugins.dhcp.identity_lease " [no]"
Derive user-defined MAC address from hash of IKEv2 identity
.TP
.BR charon.plugins.dhcp.server " [255.255.255.255]"
DHCP server unicast or broadcast IP address
.TP
.BR charon.plugins.eap-aka.request_identity " [yes]"

.TP
.BR charon.plugins.eap-aka-3ggp2.seq_check

.TP
.BR charon.plugins.eap-gtc.pam_service " [login]"
PAM service to be used for authentication
.TP
.BR charon.plugins.eap-radius.class_group " [no]"
Use the
.I class
attribute sent in the RADIUS-Accept message as group membership information that
is compared to the groups specified in the
.B rightgroups
option in
.B ipsec.conf (5).
.TP
.BR charon.plugins.eap-radius.eap_start " [no]"
Send EAP-Start instead of EAP-Identity to start RADIUS conversation
.TP
.BR charon.plugins.eap-radius.filter_id " [no]"
If the RADIUS
.I tunnel_type
attribute with value
.B ESP
is received, use the
.I filter_id 
attribute sent in the RADIUS-Accept message as group membership information that
is compared to the groups specified in the
.B rightgroups
option in
.B ipsec.conf (5).
.TP
.BR charon.plugins.eap-radius.id_prefix
Prefix to EAP-Identity, some AAA servers use a IMSI prefix to select the
EAP method
.TP
.BR charon.plugins.eap-radius.nas_identifier " [strongSwan]"
NAS-Identifier to include in RADIUS messages
.TP
.BR charon.plugins.eap-radius.port " [1812]"
Port of RADIUS server (authentication)
.TP
.BR charon.plugins.eap-radius.secret
Shared secret between RADIUS and NAS
.TP
.BR charon.plugins.eap-radius.server
IP/Hostname of RADIUS server
.TP
.BR charon.plugins.eap-radius.servers
Section to specify multiple RADIUS servers. The
.BR nas_identifier ,
.BR secret ,
.B sockets
and
.B port
options can be specified for each server. A server's IP/Hostname can be
configured using the
.B address
option. For each RADIUS server a priority can be specified using the
.BR preference " [0]"
option.
.TP
.BR charon.plugins.eap-radius.sockets " [1]"
Number of sockets (ports) to use, increase for high load
.TP
.BR charon.plugins.eap-sim.request_identity " [yes]"

.TP
.BR charon.plugins.eap-simaka-sql.database

.TP
.BR charon.plugins.eap-simaka-sql.remove_used

.TP
.BR charon.plugins.eap-tls.fragment_size " [1024]"
Maximum size of an EAP-TLS packet
.TP
.BR charon.plugins.eap-tls.max_message_count " [32]"
Maximum number of processed EAP-TLS packets
.TP
.BR charon.plugins.eap-tnc.fragment_size " [50000]"
Maximum size of an EAP-TNC packet
.TP
.BR charon.plugins.eap-tnc.max_message_count " [10]"
Maximum number of processed EAP-TNC packets
.TP
.BR charon.plugins.eap-ttls.fragment_size " [1024]"
Maximum size of an EAP-TTLS packet
.TP
.BR charon.plugins.eap-ttls.max_message_count " [32]"
Maximum number of processed EAP-TTLS packets
.TP
.BR charon.plugins.eap-ttls.phase2_method " [md5]"
Phase2 EAP client authentication method
.TP
.BR charon.plugins.eap-ttls.phase2_piggyback " [no]"
Phase2 EAP Identity request piggybacked by server onto TLS Finished message
.TP
.BR charon.plugins.eap-ttls.phase2_tnc " [no]"
Start phase2 EAP TNC protocol after successful client authentication
.TP
.BR charon.plugins.eap-ttls.request_peer_auth " [no]"
Request peer authentication based on a client certificate
.TP
.BR charon.plugins.ha.fifo_interface " [yes]"

.TP
.BR charon.plugins.ha.heartbeat_delay " [1000]"

.TP
.BR charon.plugins.ha.heartbeat_timeout " [2100]"

.TP
.BR charon.plugins.ha.local

.TP
.BR charon.plugins.ha.monitor " [yes]"

.TP
.BR charon.plugins.ha.pools

.TP
.BR charon.plugins.ha.remote
 
.TP
.BR charon.plugins.ha.resync " [yes]"

.TP
.BR charon.plugins.ha.secret

.TP
.BR charon.plugins.ha.segment_count " [1]"

.TP
.BR charon.plugins.led.activity_led

.TP
.BR charon.plugins.led.blink_time " [50]"

.TP
.BR charon.plugins.kernel-klips.ipsec_dev_count " [4]"
Number of ipsecN devices
.TP
.BR charon.plugins.kernel-klips.ipsec_dev_mtu " [0]"
Set MTU of ipsecN device
.TP
.BR charon.plugins.load-tester
Section to configure the load-tester plugin, see LOAD TESTS
.TP
.BR charon.plugins.resolve.file " [/etc/resolv.conf]"
File where to add DNS server entries
.TP
.BR charon.plugins.sql.database
Database URI for charons SQL plugin
.TP
.BR charon.plugins.sql.loglevel " [-1]"
Loglevel for logging to SQL database
.TP
.BR charon.plugins.tnc-imc.preferred_language " [en]"
Preferred language for TNC recommendations
.TP
.BR charon.plugins.tnc-imc.tnc_config " [/etc/tnc_config]"
TNC IMC configuration directory
.TP
.BR charon.plugins.tnc-imv.tnc_config " [/etc/tnc_config]"
TNC IMV configuration directory
.SS libstrongswan section
.TP
.BR libstrongswan.crypto_test.bench " [no]"

.TP
.BR libstrongswan.crypto_test.bench_size " [1024]"

.TP
.BR libstrongswan.crypto_test.bench_time " [50]"

.TP
.BR libstrongswan.crypto_test.on_add " [no]"
Test crypto algorithms during registration
.TP
.BR libstrongswan.crypto_test.on_create " [no]"
Test crypto algorithms on each crypto primitive instantiation
.TP
.BR libstrongswan.crypto_test.required " [no]"
Strictly require at least one test vector to enable an algorithm
.TP
.BR libstrongswan.crypto_test.rng_true " [no]"
Whether to test RNG with TRUE quality; requires a lot of entropy
.TP
.BR libstrongswan.dh_exponent_ansi_x9_42 " [yes]"
Use ANSI X9.42 DH exponent size or optimum size matched to cryptographical
strength
.TP
.BR libstrongswan.ecp_x_coordinate_only " [yes]"
Compliance with the errata for RFC 4753
.TP
.BR libstrongswan.integrity_test " [no]"
Check daemon, libstrongswan and plugin integrity at startup
.TP
.BR libstrongswan.leak_detective.detailed " [yes]"
Includes source file names and line numbers in leak detective output
.SS libstrongswan.plugins subsection
.TP
.BR libstrongswan.plugins.attr-sql.database
Database URI for attr-sql plugin used by charon and pluto
.TP
.BR libstrongswan.plugins.attr-sql.lease_history " [yes]"
Enable logging of SQL IP pool leases
.TP
.BR libstrongswan.plugins.gcrypt.quick_random " [no]"
Use faster random numbers in gcrypt; for testing only, produces weak keys!
.TP
.BR libstrongswan.plugins.openssl.engine_id " [pkcs11]"
ENGINE ID to use in the OpenSSL plugin
.TP
.BR libstrongswan.plugins.pkcs11.modules

.TP
.BR libstrongswan.plugins.pkcs11.use_hasher " [no]"

.TP
.BR libstrongswan.plugins.x509.enforce_critical " [no]"
Discard certificates with unsupported or unknown critical extensions
.SS libtls section
.TP
.BR libtls.cipher
List of TLS encryption ciphers
.TP
.BR libtls.key_exchange
List of TLS key exchange methods
.TP
.BR libtls.mac
List of TLS MAC algorithms
.TP
.BR libtls.suites
List of TLS cipher suites
.SS manager section
.TP
.BR manager.database
Credential database URI for manager
.TP
.BR manager.debug " [no]"
Enable debugging in manager
.TP
.BR manager.load
Plugins to load in manager
.TP
.BR manager.socket
FastCGI socket of manager, to run it statically
.TP
.BR manager.threads " [10]"
Threads to use for request handling
.TP
.BR manager.timeout " [15m]"
Session timeout for manager
.SS mediation client section
.TP
.BR medcli.database
Mediation client database URI
.TP
.BR medcli.dpd " [5m]"
DPD timeout to use in mediation client plugin
.TP
.BR medcli.rekey " [20m]"
Rekeying time on mediation connections in mediation client plugin
.SS mediation server section
.TP
.BR medsrv.database
Mediation server database URI
.TP
.BR medsrv.debug " [no]"
Debugging in mediation server web application
.TP
.BR medsrv.dpd " [5m]"
DPD timeout to use in mediation server plugin
.TP
.BR medsrv.load
Plugins to load in mediation server plugin
.TP
.BR medsrv.password_length " [6]"
Minimum password length required for mediation server user accounts
.TP
.BR medsrv.rekey " [20m]"
Rekeying time on mediation connections in mediation server plugin
.TP
.BR medsrv.socket
Run Mediation server web application statically on socket
.TP
.BR medsrv.threads " [5]"
Number of thread for mediation service web application
.TP
.BR medsrv.timeout " [15m]"
Session timeout for mediation service
.SS openac section
.TP
.BR openac.load
Plugins to load in ipsec openac tool
.SS pki section
.TP
.BR pki.load
Plugins to load in ipsec pki tool
.SS pluto section
.TP
.BR pluto.dns1
.TQ
.BR pluto.dns2
DNS servers assigned to peer via Mode Config
.TP
.BR pluto.load
Plugins to load in IKEv1 pluto daemon
.TP
.BR pluto.nbns1
.TQ
.BR pluto.nbns2
WINS servers assigned to peer via Mode Config
.TP
.BR pluto.threads " [4]"
Number of worker threads in pluto
.SS pluto.plugins section
.TP
.BR pluto.plugins.attr
Section to specify arbitrary attributes that are assigned to a peer via
Mode Config
.TP
.BR charon.plugins.kernel-klips.ipsec_dev_count " [4]"
Number of ipsecN devices
.TP
.BR charon.plugins.kernel-klips.ipsec_dev_mtu " [0]"
Set MTU of ipsecN device
.SS pool section
.TP
.BR pool.load
Plugins to load in ipsec pool tool
.SS scepclient section
.TP
.BR scepclient.load
Plugins to load in ipsec scepclient tool
.SS starter section
.TP
.BR starter.load_warning " [yes]"
Disable charon/pluto plugin load option warning

.SH LOGGER CONFIGURATION
The options described below provide a much more flexible way to configure
loggers for the IKEv2 daemon charon than using the
.B charondebug
option in
.BR ipsec.conf (5).
.PP
.B Please note
that if any loggers are specified in strongswan.conf,
.B charondebug
does not have any effect.
.PP
There are currently two types of loggers defined:
.TP
.B File loggers
Log directly to a file and are defined by specifying the full path to the
file as subsection in the
.B charon.filelog
section. To log to the console the two special filenames
.BR stdout " and " stderr
can be used.
.TP
.B Syslog loggers
Log into a syslog facility and are defined by specifying the facility to log to
as the name of a subsection in the
.B charon.syslog
section. The following facilities are currently supported:
.BR daemon " and " auth .
.PP
Multiple loggers can be defined for each type with different log verbosity for
the different subsystems of the daemon.
.SS Options
.TP
.BR charon.filelog.<filename>.default " [1]"
.TQ
.BR charon.syslog.<facility>.default
Specifies the default loglevel to be used for subsystems for which no specific
loglevel is defined.
.TP
.BR charon.filelog.<filename>.<subsystem> " [<default>]"
.TQ
.BR charon.syslog.<facility>.<subsystem>
Specifies the loglevel for the given subsystem.
.TP
.BR charon.filelog.<filename>.append " [yes]"
If this option is enabled log entries are appended to the existing file.
.TP
.BR charon.filelog.<filename>.flush_line " [no]"
Enabling this option disables block buffering and enables line buffering.
.TP
.BR charon.filelog.<filename>.ike_name " [no]"
.TQ
.BR charon.syslog.<facility>.ike_name
Prefix each log entry with the connection name and a unique numerical
identifier for each IKE_SA.
.TP
.BR charon.filelog.<filename>.time_format
Prefix each log entry with a timestamp. The option accepts a format string as
passed to
.BR strftime (3).

.SS Subsystems
.TP
.B dmn
Main daemon setup/cleanup/signal handling
.TP
.B mgr
IKE_SA manager, handling synchronization for IKE_SA access
.TP
.B ike
IKE_SA
.TP
.B chd
CHILD_SA
.TP
.B job
Jobs queueing/processing and thread pool management
.TP
.B cfg
Configuration management and plugins
.TP
.B knl
IPsec/Networking kernel interface
.TP
.B net
IKE network communication
.TP
.B enc
Packet encoding/decoding encryption/decryption operations
.TP
.B tls
libtls library messages
.TP
.B lib
libstrongwan library messages
.SS Loglevels
.TP
.B -1
Absolutely silent
.TP
.B 0
Very basic auditing logs, (e.g. SA up/SA down)
.TP
.B 1
Generic control flow with errors, a good default to see whats going on
.TP
.B 2
More detailed debugging control flow
.TP
.B 3
Including RAW data dumps in Hex
.TP
.B 4
Also include sensitive material in dumps, e.g. keys
.SS Example
.PP
.EX
	charon {
		filelog {
			/var/log/charon.log {
				time_format = %b %e %T
				append = no
				default = 1
			}
			stderr {
				ike = 2
				knl = 3
				ike_name = yes
			}
		}
		syslog {
			# enable logging to LOG_DAEMON, use defaults
			daemon {
			}
			# minimalistic IKE auditing logging to LOG_AUTHPRIV
			auth {
				default = -1
				ike = 0
			}
		}
	}
.EE

.SH LOAD TESTS
To do stability testing and performance optimizations, the IKEv2 daemon charon
provides the load-tester plugin. This plugin allows to setup thousands of
tunnels concurrently against the daemon itself or a remote host.
.PP
.B WARNING:
Never enable the load-testing plugin on productive systems. It provides
preconfigured credentials and allows an attacker to authenticate as any user.
.SS Options
.TP
.BR charon.plugins.load-tester.child_rekey " [600]"
Seconds to start CHILD_SA rekeying after setup
.TP
.BR charon.plugins.load-tester.delay " [0]"
Delay between initiatons for each thread
.TP
.BR charon.plugins.load-tester.delete_after_established " [no]"
Delete an IKE_SA as soon as it has been established
.TP
.BR charon.plugins.load-tester.dynamic_port " [0]"
Base port to be used for requests (each client uses a different port)
.TP
.BR charon.plugins.load-tester.enable " [no]"
Enable the load testing plugin
.TP
.BR charon.plugins.load-tester.fake_kernel " [no]"
Fake the kernel interface to allow load-testing against self
.TP
.BR charon.plugins.load-tester.ike_rekey " [0]"
Seconds to start IKE_SA rekeying after setup
.TP
.BR charon.plugins.load-tester.initiators " [0]"
Number of concurrent initiator threads to use in load test
.TP
.BR charon.plugins.load-tester.initiator_auth " [pubkey]"
Authentication method(s) the intiator uses
.TP
.BR charon.plugins.load-tester.iterations " [1]"
Number of IKE_SAs to initate by each initiator in load test
.TP
.BR charon.plugins.load-tester.pool
Provide INTERNAL_IPV4_ADDRs from a named pool
.TP
.BR charon.plugins.load-tester.proposal " [aes128-sha1-modp768]"
IKE proposal to use in load test
.TP
.BR charon.plugins.load-tester.remote " [127.0.0.1]"
Address to initiation connections to
.TP
.BR charon.plugins.load-tester.responder_auth " [pubkey]"
Authentication method(s) the responder uses
.TP
.BR charon.plugins.load-tester.request_virtual_ip " [no]"
Request an INTERNAL_IPV4_ADDR from the server
.TP
.BR charon.plugins.load-tester.shutdown_when_complete " [no]"
Shutdown the daemon after all IKE_SAs have been established
.SS Configuration details
For public key authentication, the responder uses the
.B \(dqCN=srv, OU=load-test, O=strongSwan\(dq
identity. For the initiator, each connection attempt uses a different identity
in the form
.BR "\(dqCN=c1-r1, OU=load-test, O=strongSwan\(dq" ,
where the first number inidicates the client number, the second the
authentication round (if multiple authentication is used).
.PP
For PSK authentication, FQDN identities are used. The server uses
.BR srv.strongswan.org ,
the client uses an identity in the form
.BR c1-r1.strongswan.org .
.PP
For EAP authentication, the client uses a NAI in the form
.BR 100000000010001@strongswan.org .
.PP
To configure multiple authentication, concatenate multiple methods using, e.g.
.EX
	initiator_auth = pubkey|psk|eap-md5|eap-aka
.EE
.PP
The responder uses a hardcoded certificate based on a 1024-bit RSA key.
This certificate additionally serves as CA certificate. A peer uses the same
private key, but generates client certificates on demand signed by the CA
certificate. Install the Responder/CA certificate on the remote host to
authenticate all clients.
.PP
To speed up testing, the load tester plugin implements a special Diffie-Hellman
implementation called modpnull. By setting
.EX
	proposal = aes128-sha1-modpnull
.EE
this wicked fast DH implementation is used. It does not provide any security
at all, but allows to run tests without DH calculation overhead.
.SS Examples
.PP
In the simplest case, the daemon initiates IKE_SAs against itself using the
loopback interface. This will actually establish double the number of IKE_SAs,
as the daemon is initiator and responder for each IKE_SA at the same time.
Installation of IPsec SAs would fails, as each SA gets installed twice. To
simulate the correct behavior, a fake kernel interface can be enabled which does
not install the IPsec SAs at the kernel level.
.PP
A simple loopback configuration might look like this:
.PP
.EX
	charon {
		# create new IKE_SAs for each CHILD_SA to simulate
		# different clients
		reuse_ikesa = no
		# turn off denial of service protection
		dos_protection = no

		plugins {
			load-tester {
				# enable the plugin
				enable = yes
				# use 4 threads to initiate connections
				# simultaneously
				initiators = 4
				# each thread initiates 1000 connections
				iterations = 1000
				# delay each initiation in each thread by 20ms
				delay = 20
				# enable the fake kernel interface to
				# avoid SA conflicts
				fake_kernel = yes
			}
		}
	}
.EE
.PP
This will initiate 4000 IKE_SAs within 20 seconds. You may increase the delay
value if your box can not handle that much load, or decrease it to put more
load on it. If the daemon starts retransmitting messages your box probably can
not handle all connection attempts.
.PP
The plugin also allows to test against a remote host. This might help to test
against a real world configuration. A connection setup to do stress testing of
a gateway might look like this:
.PP
.EX
	charon {
		reuse_ikesa = no
		threads = 32

		plugins {
			load-tester {
				enable = yes
				# 10000 connections, ten in parallel
				initiators = 10
				iterations = 1000
				# use a delay of 100ms, overall time is:
				# iterations * delay = 100s
				delay = 100
				# address of the gateway
				remote = 1.2.3.4
				# IKE-proposal to use
				proposal = aes128-sha1-modp1024
				# use faster PSK authentication instead
				# of 1024bit RSA
				initiator_auth = psk
				responder_auth = psk
				# request a virtual IP using configuration
				# payloads
				request_virtual_ip = yes
				# enable CHILD_SA every 60s
				child_rekey = 60
			}
		}
	}
.EE

.SH IKEv2 RETRANSMISSION
Retransmission timeouts in the IKEv2 daemon charon can be configured globally
using the three keys listed below:
.PP
.RS
.nf
.BR charon.retransmit_base " [1.8]"
.BR charon.retransmit_timeout " [4.0]"
.BR charon.retransmit_tries " [5]"
.fi
.RE
.PP
The following algorithm is used to calculate the timeout:
.PP
.EX
	relative timeout = retransmit_timeout * retransmit_base ^ (n-1)
.EE
.PP
Where
.I n
is the current retransmission count.
.PP
Using the default values, packets are retransmitted in:

.TS
l r r
---
lB r r.
Retransmission	Relative Timeout	Absolute Timeout
1	4s	4s
2	7s	11s
3	13s	24s
4	23s	47s
5	42s	89s
giving up	76s	165s
.TE

.SH FILES
/etc/strongswan.conf

.SH SEE ALSO
ipsec.conf(5), ipsec.secrets(5), ipsec(8)
.SH HISTORY
Written for the
.UR http://www.strongswan.org
strongSwan project
.UE
by Tobias Brunner, Andreas Steffen and Martin Willi.