NAT Port Mapping Protocol

NAT Port Mapping Protocol (NAT -PMP ) is a RFC 6886, presented by Apple in June 2005 as an alternative to more conventional UPnP protocol, which is implemented in many NAT routers. NAT -PMP allows a computer in a private network ( behind a NAT router) to automatically configure the router so that the computer from outside the private network is reachable. It essentially automates the so-called port forwarding. NAT -PMP, such as UPnP also allows a program to request all incoming external data on a specific TCP or UDP port.

Integrated in the protocol is a mechanism to identify the public IP address of the NAT gateway. This is, for example, a peer-to -peer program is able to address this, including port to make his peers aware of what a communication between the two simplified or made ​​possible.

This protocol is implemented in a number of current Apple products, such as Mac OS X 10.4 (Tiger) or the AirPort Extreme and AirPort Express network devices, but also in Bonjour for Windows. The alternative open source firmware Tomato for based on the Broadcom chipset wireless router supported since Version 1.24 also the protocol.