The roadwarriors carol and dave set up a connection each
to gateway moon. The authentication is based on X.509 certificates
and includes a Postquantum Preshared Key (PPK) that's also mixed into the
derived key material. The PPK_ID used by dave is unknown to moon
but since both peers don't enforce the use of a PPK they fall back to regular
authentication by use of the authentication data provided in the NO_PPK_AUTH
notify.
Upon the successful establishment of the IPsec tunnels, the updown script
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.