Port forwarding allows the network administrators to use one public IP address for all external communications on the Internet while dedicating multiple servers with different IP addresses and ports to the task internally. It also helps to hide from the outside world what services are running on the network.
Using the IP/Port forwarding feature on Firewall/Router, you can make a host on your network accessible to hosts on the Internet (outside your network), even though they are behind Firewall. Entire IP address can be forwarded to allow access to all the ports of a computer or only specific ports can be forwarded. You can also select protocol while creating an IP/Port forwarding rule.
<aside> đź’ˇ Requirement: Static WAN IP
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Typically, a Firewall protects your network from the outside world by limiting external access to your internal network.
But some devices and programs like IP cameras, Web servers, Mail Servers and online games need a connection from the outside internet that’s unimpeded by a firewall.
But you don’t want all your devices to have an open connection, because that’s not secure. The solution is port forwarding. Port forwarding tells a Firewall When a connection request comes through a specific port (that you specify), send that connection to a specific device (of your choosing). Your other devices will remain unaffected by this rule.