Configuring Port Forwarding in Industrial Router

Port forwarding is an application of network address translation, which maps a port of the IP address of a public network host to a computer in an internal network to provide corresponding services. When a user accesses a port with an IP address, the server automatically requests the corresponding computer mapped to the local area network. Port forwarding function can also complete some specific proxy functions, such as proxy POP, SMTP, Telnet and other protocols. Theoretically, there are 64511 ports available-subtract 1024 reserved ports from 65535 total ports.

The advantages of using port forwarding for pictures include:
01. helps to save IPv4 address resources and alleviate the shortage of IPv4 addresses.
02. helps to avoid attacks from outside the network and hide and protect computers inside the network.
03.  used to prevent unnecessary communication on the network.
Types of port forwarding
1) Static local port forwarding Open a fixed port on the gateway and configure forwarding rules so that all data received through this port will be forwarded to the designated IP and port of the intranet. No matter whether the connection is activated or not, the forwarding rules will always be maintained, so you can access the hosts in the intranet from the public network.
2) Dynamic port forwarding If the computer in the intranet wants to access the public network, it will send a data packet to the gateway. The packet header includes the destination IP/ port and the local IP/ port. The gateway will replace the local IP/ port with its public IP and an unused port, and record the forwarding relationship for future packet forwarding. Then send the data to the destination website, and the website will respond after receiving the data and send the data to the corresponding port of the gateway. The gateway then forwards the data to the computer in the intranet to realize the communication between the intranet and the public network. When the connection is closed, the gateway will release the allocated port so that future connections can continue to use the port.