Set up port forwarding on the router - so it'll work

You can set up port forwarding on your router to send incoming data packets from the Internet directly to the correct computer in the network. Computers on the home network are usually invisible to outsiders. Port forwarding can also be used to address a computer behind a router, for example from peer-to-peer software or multiplayer games.

Set up port forwarding

You can make settings for individual ports in almost every router. You will often find the option under the keyword port forwarding, port sharing or port forwarding. But keep an eye on security: don't open more ports than you really need.

1. Search for the corresponding menu entry after you have logged on to your router.
2. First enter the port that the software will use on your target computer. As an example: if you want to route HTTP requests from outside to a server, you do a port forwarding for TCP port 80. The reason: outside computers always send their HTTP requests to this port.
3. You can also specify a number of ports if your software uses multiple ports. (For example: TCP port 1120 - 1124 or 1120, 1124, 1128).
4. Now you determine to which computer in the network the forwarding is directed. Therefore, enter the IP of the computer on which the program is running for which you need the forwarding. As an example: if you have set up an HTTP server that you want to reach from outside, then enter its IP now.
5. Finally, you determine which port on your target computer the forwarding should arrive at. In the example, this would be port 80 for HTTP, so forward the request back to TCP port 80 on the target computer. The software installed there only listens to data that arrives on this port.
6. Finished! With confirmation of the forwarding, incoming data from the Internet is now forwarded to the correct computer and port. Your software can now respond to these requests.
7. If something still sticks somewhere: check whether the set ports are really being used in your software or whether you have changed a port in previous attempts. Especially with peer-to-peer applications, the ports can be set manually.

The most important ports for your router

Different services or programs usually use their own port for their purpose. If you want to set up forwarding, you must know the port that the corresponding program uses. A distinction is also made between UDP and TCP ports.

• HTTP uses TCP port 80 as the standard port, while HTTPS uses TCP port 443.
• Teamspeak uses UDP ports 8767 and 8768.
• eMule uses UDP port 8767, but often also TCP port 4662. You can make precise settings yourself in eMule.
• FTP (File Transfer Protocol) uses TCP port 20.
• SSH (Secure Shell) uses TCP and UDP port 22.
• If you want to know exactly, you can look up the documentation for your software or go to the Internet. Especially for games, you can often research the information in fan forums. You can also find a list of standardized ports on Wikipedia.

Sometimes it can also be due to the firewall if something doesn't work. Read the practical tip below on how to open ports in the firewall under Windows 7.