The roadwarriors <b>carol</b> and <b>dave</b> set up an IPv6-in-IPv4 tunnel
connection each to gateway <b>moon</b>. The authentication is based on <b>X.509
certificates</b>. Both <b>carol</b> and <b>dave</b> request a virtual IPv6
address from <b>moon</b> via the IKEv1 mode config payload.
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Upon the successful establishment of the ESP tunnels, automatically inserted
ip6tables-based firewall rules let pass the tunneled traffic. In order to test
both tunnel and firewall, both <b>carol</b> and <b>dave</b> send an IPv6 ICMP
request to the client <b>alice</b> behind the gateway <b>moon</b> using the
ping6 command.
