Patent ID: 7826602

Claim:
A method for enabling voice over internet protocol (VoIP) calls across a firewall, comprising: receiving, by the firewall, a registration message from a private user device including a private internet protocol (IP) address associated with the private user device; associating, by the firewall, the private user device and private IP address with a public IP address and discrete port number, the public IP address being further associated, by the firewall, with at least one other private user device; modifying, by the firewall, the registration message to include the public IP address and discrete port number; forwarding, by the firewall, the modified registration message to a proxy server for registration; receiving, by the firewall and in response to forwarding the modified registration message, a call invitation message from the proxy server, the proxy server forwarding the call invitation message on behalf of a public user device, the call invitation message being directed to the public IP address and a different discrete port number associated with one private user device of the at least one private user device; retrieving, by the firewall, a different private IP address associated with the one private user device; translating, by the firewall, the call invitation message to include the different private IP address associated with the one private user device; and forwarding, by the firewall, the call invitation message to the one private user device based on the different private IP address associated with the one private user device.