A connection between the subnets behind the gateways moon and sun is set up. The key exchange is based on NTRU encryption with a security strength of 128 bits. The ANSI X9.98 NTRU encryption parameter set used is optimized for bandwidth.

The authentication is based on X.509 certificates. 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.