An IPv6 ESP tunnel connection between the gateways moon and sun 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, leftfirewall=yes 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 alice behind moon sends an IPv6 ICMP request to client bob behind sun using the ping6 command.