The roadwarriors carol and dave set up a connection each to gateway moon. Both carol and dave request a virtual IP via the IKE Mode Config protocol by using the leftsourceip=%modeconfig parameter. 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.