Port forwarding

application of network address translation

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.



  1. "Definition of: port forwarding". PC Magazine. Archived from the original on 2008-10-07. Retrieved 2008-10-11.
  2. Rory Krause. "Using ssh Port Forwarding to Print at Remote Locations". Linux Journal. Retrieved 2008-10-11.
  3. Jeff "Crash" Goldin. "How to set up a home web server". Red Hat. Retrieved 2008-10-11.