Originally Posted by Derrick
DMZ may still work. The card would not be any more vulnerable to hacking in the DMZ than it would with its own public ip.

With VoIP, sometimes a DMZ still won't work. I don't know much about Vertical but as one example Toshiba CIX IP phones have never worked through any NAT, even with DMZ. Sometimes I have to explain to a customer's IT that I really do need another public IP address (or a VPN) for their remote phones to work.

Toshiba finally got it to work with NAT on their IPEdge system by using a relay service that knows how to manage NAT IP information.