Certain ports need to be open on your router for certain video games and programs to work properly. Although the router has some ports open by default, most are closed and only usable if you manually open these ports. If your online video games, file server, or other network programs are not working, open the router and the specific ports that the application requires.

The traffic that goes through your router goes through ports. Each port is like a special pipe that is created for a specific type of traffic. When you open a port on a router, it allows a certain type of data to move through the router.

Opening a port and choosing a device on the network to forward those requests to is called port forwarding. Port forwarding is like connecting a pipe from the router to the device that needs to use the port: there is a direct line of sight between the two that allows data to flow.

For example, FTP servers listen for incoming connections on port 21. If you have an FTP server set up that no one outside your network can connect to, open port 21 on your router and forward it to the computer you are using as the server. When you do this, that new, special pipe moves files from the server, through the router, and out of the network to the FTP client that is communicating with it.