[Freeswitch-users] Internal and external ip addresses

I've been running FS for some years with two nic's, one on the internal network which is configured on the FS internal profile, the other nic on the external network with an internet ip. Is this how internal and external were designed to be used? Most recently I've installed a new FS machine and noticed some problems with registering to a gateway on the external interface, which is why I ask these questions. thanks -kim