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, <b>leftfirewall=yes</b>
automatically inserts ip6tables-based firewall rules that 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.
