Recently my roomate and I have bought the new Call of Duty: Modern Warfare 2. 

 If anyone is familier with the game, when you enter the game it will tell you whether or not your NAT type is Strict of Open.  Now the issue is that my roomates shows that his is open, while mine shows that it is Strict.  

 Also when I go into my router to see if I can add my port or computer to the Upnp Portmap table, there is no way to do that.

Can anyone tell me why his IP address is the only one showing up in the Portmap Table?  

What can I do to open my NAT type?  

 Does this include Port Forwarding?