The roadwarrior dave tries to set up a connection to roadwarrior carol
but because carol has set the strongswan.conf option initiator_only = yes
she ignores the repeated IKE requests sent by dave.
After the failed connection attempt by dave, roadwarrior carol sets up a
connection to gateway moon. The authentication is based on X.509 certificates.
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, carol pings the client alice behind
the gateway moon.