I've played around with Trixbox before and haven't ever had any issues picking up the Public IP. However, on this installation, everything is working except for the Trix CE 2.8 picking up the Public IP. We are testing a couple of things and for the sake of simplicity, were throwing it on a VM box. In the process of troubleshooting, I've even tried adding a 2nd NIC but that didn't work (with a public IP). So, to the genius Linux people - PLEASE HELP! :)
Details - Were behind ISA 2006. Trying to run IAX2. Opened UPD 5060 both ways. Everything else is working fine. ISA handles NAT as well as is the Gateway. Checked all NIC settings multiple times.