The CommuniGate Pro SIP and XIMSS Modules detect the session initiation requests that are sent from one side of NAT to the other side (a request from a LAN client to a party on the Internet/WAN and vice versa). In this case, the Server uses some local server port (or a set of ports depending on the media protocol(s) used) to build a media stream proxy. The Server then modifies the session initiation request to direct the traffic from both sides to that proxy.
The Media Proxy relays media data between the "LAN leg" and the "WAN leg" of the media connection:
The CommuniGate Pro SIP and XIMSS Modules detect session update (SIP re-INVITE) and session close (SIP BYE) requests and update and remove the Media Proxies accordingly. The time-out mechanism is used to remove "abandoned" Media Proxies.
The CommuniGate Pro provides NAT proxy services for:
Note: The Server automatically builds Media Proxies when it relays requests from IPv4 addresses to IPv6 addresses and vice versa.