Universal Plug and Play
From AMule Project FAQ
Universal Plug and Play (uPnP) is a new feature of aMule (CVS) which allows you to automatically configure the ports on your router, provided your router supports uPnP. This functionality is still being tested and should appear soon in an official release.
External link
The right libupnp for aMule
It is highly recommended to use libupnp version 1.4.1.
You can download the source tarball at the sourceforge project page.
There are some user made packages available:
OpenSuse 10.2 by Gerd78
Ubuntu 6.10 by Wuischke