What is port forwarding?

Port forwarding is a method of making a computer on your network accessible to computers on the Internet

it is  the state the port is sending and receiving traffic

Pass or block specific port through Firewall from External to internal with a Reverse

port mapping is an application of network address translation (NAT) that redirects a communication request from one address and port number combination to another while the packets are traversing a network gateway, such as a router or firewall.

 IP type applications. There are many other reasons you may need to forward a port, this is not an exhaustive list.

Port forwarding allows remote computers (for example, computers on the Internet to connect to a specific computer or service within a private local-area network (LAN).

Port forwarding is the behind-the-scenes process of intercepting data traffic headed for a computer's IP/port combination and redirecting it to a different IP and/or port.

By default, the firewall of a NETGEAR router blocks all connection attempts by devices on the Internet to devices in your local network. This is called inbound traffic. If you want devices on the Internet to connect to devices on your local network (for example, you have an IP Camera or an FTP server that you want to be accessible via the Internet), you will have to reconfigure the router. Here are three ways to do that:

1. Universal Plug and Play (UPnP). If the router and the device on your local network both support UPnP, the required router configuration will happen automatically.  
2. Port Forwarding, also called inbound firewall rules. You create port forwarding rules that look into the header of each inbound packet, and either block it or forward it to specified devices on you local network, based on the source IP address, destination TCP port number, and other characteristics of the packet. Packets with different characteristics can be forwarded to different devices on your local network.

port forwarding can be described as an application of network address translation  (NAT) that redirects a comm request from one ip address combination to another while the Data are traversing a network gateway.

Port forwarding is also know as port mapping. It is a process of intercepting data traffic headed for a computer's IP/port combination and redirecting it to a different 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, proxy server or firewall.

it is  mapping is an application of network address translation redirects a communication request from one address to another

Port forwarding or port redirection is implemented in static NAT when we allow internet users to access servers on specific port by changing the source and destination port in NAT.