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 prompted for your password. Enter your password now. By default the password is admin. Click the Ok button to log in to your router.

In the menu on the left hand side of your screen, click the Firewall link.

At the top of your screen click the Special Application tab.

Click the New button to create a new profile.

Use the Choose Application drop down box to select a service to forward. If you do not see the service you wish to forward in this list, select Other. With other selected your screen should change a bit.

Enter a name in the Application Name box. It doesn't really matter what you put into this box, but something that will remind you why these ports are forwarded would be a good idea. If you are unsure of the port range/ranges check the Ports list page or the software manufacture's homepage. Put the trigger ports into the Trigger Port box. The trigger ports are the ports that your computer will use to contact the computer on the internet. Enter the incoming ports into the Incoming Ports box. The incoming ports are the ports of your computer that need to be forwarded. These ports can be entered as a list 23,45,69, a range 500-600, or a combination of both 23,45,500-600. Put a check in the Enable box at the bottom, and then click the Add button to save your changes.

And that's it! You're done!