warcraft 3 hosting issue.. please help


My Yngy is My HoneY!
Folding Team
Ok heres the deal, i have a router and i have portforwarded the ports required (www.portforward.com) and others can join my game. My problem is, when i have a lan with another friend, he cant join but the net can. So my question is, whats wrong? all ip's have been manually set. I have read some posts on the net and hear all sorts of excuses but not really an answer, some say that he cant because although the ip's are different, the internet ip is the same (203.**.*.*) or what ever. Anyone know anything? ive heard, bridging, port forwarding half half aka comp1 forwards 6112-6114, and comp2 forwards 6115-6119, others want triggering sigh..anyone pls. I mean how do lan cafe's do it?
Not sure about this.

I have my 2nd computer with Lan Card.
Then it is linked to my main computer, to play CS.
Work fine even with WC3 FT Dota.