I would highly recommend not using the DMZ mode on your router as this exposes your entire computer to the internet! Your firewall will no longer offer any protection either: this is very dangerous and not worth chancing just to play a game online.
If you want to find people to play with install tunggle then go to room shooter>tactical shooter> splinter cell conviction. Lots of legit copy owners are using tunggle to find and add people to your friends list. 153554b96e