An IPv6 ESP connection between the hosts <b>moon</b> and <b>sun</b> is successfully set up.
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 host-to-host tunnel
and the firewall rules, <b>moon</b> sends an IPv6 ICMP request to <b>sun</b> using the ping6 command.