The roadwarriors carol and dave set up a connection each to gateway moon using IKEv1 Aggressive Mode. The authentication is based on distinct pre-shared keys and Fully Qualified Domain Names. Upon the successful establishment of the IPsec tunnels, leftfirewall=yes automatically inserts iptables-based firewall rules that let pass the tunneled traffic. In order to test both tunnel and firewall, both carol and dave ping the client alice behind the gateway moon.