The roadwarriors carol and dave set up a connection each to gateway moon. The gateway pushes virtual IP addresses to carol and davevia the IKEv1 Mode Config protocol in push mode.
leftfirewall=yes automatically inserts iptables-based firewall rules that let pass the tunneled traffic. In order to test the tunnels, carol and dave then ping the client alice behind the gateway moon. The source IP addresses of the two pings will be the virtual IPs carol1 and dave1, respectively.