Port forwarding is the backend process of intercepting data traffic headed for a WAN IP/port combination and redirecting it to a different LAN IP and/or port. A program that’s running on the destination computer (host) usually causes the redirection, but sometimes it can also be an intermediate hardware component, such as a router or firewall.

Port forwarding is the excellent way to preserve the public ip address space.The network administrator can set up a single public IP address on the router to translate requests to the respective server on the internal network. By using only one IP address to accomplish multiple tasks.