Warcraft III Firewall Settings for Linux

Battle.net doesn't tell you if someone can't connect to your game. That makes it really easy to just sit there thinking that nobody likes the map you picked. If you're using iptables on a linux router, you can run this script to forward port 6112 to your warcraft 3 host machine.

#/bin/bash

iptables -A PREROUTING -t nat -p tcp -d your.external.ip.address --dport 6112 -j DNAT --to your.internal.ip.address:6112

iptables -A FORWARD -p tcp -d your.internal.ip.address --dport 6112 -o eth0 -j ACCEPT

"your.internal.ip.address" should be something like 10.x.x.x or 172.16.x.x or 192.168.x.x. The "eth0" should be the interface of your network card on the internal network (it could be eth1). It should be apparent that you can change the "--dport 6112" to any port for other programs. You may wish to consult for common ports used by programs.

source : http://chatul.wordpress.com/2008/05/09/iptables-linux-cr3at3-dota-warcraft/