The solutions for NAT traversal can be classified as near-end for solutions implemented in the client side and far-end for solutions implemented on the server side. The far-end solutions are easier to manage and solve NAT traversal in all four types of NAT devices. However, these solutions impose a scalability penalty forcing the RTP media flow into media servers. Near-end solutions are harder to manage and can solve just the first three types of NAT devices but are far more scalable. The ideal solution is to use near-end NAT traversal solutions to every device that supports it (Symmetrical NAT devices don't) and use far-end NAT traversal for the SIP devices behind a symmetric firewall. We will start using a far-end NAT solution using the MediaProxy server.