Well, to port forward you would need to set an internal static IP on the computer you are using to host from. The router IP can be dynamic as you can use a dns service to host games on a dynamic IP. Some ports on some routers are stubborn and won't open unless forwarded, just an fyi as well, the local ISPs here won't even deal with a NetGear. They actually refuse to hook up internet if you are using a NetGear here.
Are you using the wireless on the router or hard wired? I've read a few notes about enabling upnp on the wireless if using that.
You are using Linux correct? I couldn't begin to tell you how to setup an internal IP on a linux box sorry
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