An IPv6 ESP tunnel connection between the gateways <b>moon</b> and <b>sun</b> is
successfully set up. It connects the two subnets hiding behind their respective
gateways. The authentication is based on X.509 certificates. Upon the successful
establishment of the IPsec tunnel, automatically inserted ip6tables-based firewall
rules let pass the tunneled traffic.
In order to test both the net-to-net tunnel and the firewall rules, client
<b>alice</b> behind <b>moon</b> sends an IPv6 ICMP request to client <b>bob</b>
behind <b>sun</b> using the ping6 command.