The roadwarriors carol and dave set up an IPv6 tunnel connection each to gateway moon. The authentication is based on distinct pre-shared keys and IPv6 addresses. Upon the successful establishment of the IPsec tunnels, automatically inserted ip6tables-based firewall rules let pass the tunneled traffic. In order to test both tunnel and firewall, both carol and dave send an IPv6 ICMP request to client alice behind the gateway moon using the ping6 command.