How do you work "port forwarding" on a router?

Answer by  A84 (90)

All routers have a page you can access on the web. If not, you need to use the cd that came with your router. This can also be downloaded from the manufacturers website. What it does is to allow a program to send data to the internet and not be stopped by the firewalls. Multiplayer games and torrents use this.

Answer by  mmonshausen (114)

The router holds an internal matching table between your requests sender information and the information he uses to request the resource you want him to. The response is routed to saved information. Using port-forwarding allows you to "hard-code" those information: everytime an request to port x will arrive, this will be transfered to specified port.