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 the username is admin, and the password is admin. Click the Ok button to log in to your router.

At the top middle of this menu it will say Applications & Gaming. Click those words. This should change the menu directly under those words. In this new menu, click Port Range Triggering. This should bring you to the following menu.

Enter the name of the application you are setting up triggering for in the Application Name box. Specify the trigger port range using the Triggered Range boxes. The lowest port number should go into the left hand box, while the highest port number should go into the right hand box. The trigger port range is the range of ports that your computer will be communication outside of your network on. Data goes out on the trigger ports. Go ahead and specify the incoming port range using the Forwarded Range boxes. These are the ports that will be opened up when a trigger port is in use. You can think of this as dynamic port forwarding. When you are using one of the trigger ports these incoming ports are forwarded to your computer from the internet. Put a checkmark into the Enabled checkbox to enable that configuration. Click Save Settings at the bottom of your screen to save your changes.

And that's it! You're done!