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.

Click Securtiy in the menu on the left side of the screen.

Click the Trigger tab near the top of the screen.

Click New Trigger. You should now be at the following screen.

Use the Transport Type drop down box to select the protocol type. Enter the trigger ports into the Port Number Start and Port Number End boxes. If you have a single trigger port, enter the number into both boxes. If you have a range of trigger ports, enter the lowest number of the range into the Port Number Start box. Then the highest number of the range into the Port Number End box. You can think of trigger ports as a on off switch for incoming ports. When there is data flowing out on the trigger ports, the incoming ports are on or forwarded. When there is no data flowing on the trigger ports, the incoming ports are off or not forwarded. Enter the ports you want to forward into the Secondary Port Number Start and Secondary Port Number End boxes. If you want to forward a single port, enter that number into both boxes. If you want to forward a range of ports, enter the lowest number of the range into the Secondary Port Number Start box. Then enter the highest number of the range into the Secondary Port Number End box. The Max Activity Interval is the number of milliseconds that the ports should be forwarded after the traffic had stopped on the trigger ports. So you should set this to something like 300000, which would be five minutes. When you're finished, click Apply.

And that's it! You're done!