Open a web browser like internet explorer or Netscape. Enter the ip address of your router in the address bar of your browser. In the picture above the address bar has http://www.google.com in it. Just replace all of that with the ip address of your router. By default the ip address should be set to 192.168.1.1.
You should see a box prompting you for your username and password. Enter your username and password now. By default both the username and password are admin. Click the Ok button to log in to your router.
Click the Application link near the left side of the page.
You should now see a new menu. In this new menu, click Port Forwarding.
Click the New button near the bottom of the page.
We will list a series of lines here that will show you exactly how to forward the ports you need to forward. Army of Two PS3 requires you to forward the 3658,6000 ports. Go ahead and enter the settings shown above into the Rule Management menu and then click Submit.
You should see another page of settings that need to be entered into one of the blank lines on your routers Rule Management page. Go ahead and enter those settings and then click Submit.
When you're finished, click Save Settings near the left side of the screen to save your changes. And that's it! You're done!