Port forwarding

Port forwarding, also referred to as port mapping,^[1] is a method of forwarding a network port from one network node to another. This technique can allow an external user to reach a port on a private IP address (inside a LAN) from the outside using a NAT-enabled router.^[2]

Port forwarding allows remote computers (e.g. public machines on the Internet) to connect to a specific computer within a private LAN.^[3]

For example:

• forwarding of port 80 to run an HTTP webserver within private LAN from internet
• forwarding of port 22 to allow Secure Shell access within private LAN from internet
• forwarding of port 21 to allow FTP access within private LAN from internet

Port forwarding is not necessary with IPv6, because every IPv6-enabled device has a public IPv6 address.