A connection between the subnets behind the gateways moon and sun is set up. The authentication is based on X.509 certificates and an RSA private key stored in PKCS12 format.

Upon the successful establishment of the IPsec tunnel, leftfirewall=yes automatically inserts iptables-based firewall rules that let pass the tunneled traffic. In order to test both tunnel and firewall, client alice behind gateway moon pings client bob located behind gateway sun.