The roadwarrior <b>alice</b> sitting behind the NAT router <b>moon</b> sets up a connection 
to gateway <b>sun</b> using IKEv2. UDP encapsulation is used to traverse the NAT router.
The authentication is based on locally loaded <b>X.509 certificates</b>.
In order to test the tunnel the NAT-ed host <b>alice</b> pings the client
<b>bob</b> behind the gateway <b>sun</b>.