Yes, it is. The setup is the following:
``` +----------+ +--------+ eth0 | Kamailio | eth1 <---> lan0 | Router | wan0 +----------+ +--------+
eth0 = 10.0.0.100 eth1 = 192.168.178.21 lan0 = 192.168.178.1 wan0 = public IP referenced by a DynDNS hostname in the advertise parameter ``` The via address is `192.168.178.21`.