Which ports do I have to configure in a firewall or router to run aMule?
One has to distinguish between incoming and outgoing connections. Normally, all ports of a router are open for sending data (outgoing connection). So, in this normal case, You only have to configure the ports for incoming connections: aMule works even with no specific ports opened, but you won’t get a HighID in this case. As mentioned above, to be given a HighID, port 4662 TCP (or the one set in the Preferences) must be listening (i.e. opened in your firewall and forwarded in your router). http://www.amule.org/wiki/index.php/FAQ_eD2k-Kademlia Apart from that port, to have an optimal ED2K experience, two more port should be enabled for listening as well: UDP ports 4672 and 4665 (that is, TCP_PORT+3) (both can be changed to any other number in the Preferences).
