Port forwarding, sometimes referred to as port mapping, is the act 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 via a NAT-enabled router.
(From Wikipedia, the free encyclopedia)
For example: If you need to allow remote access within private LAN over the internet, you need to forward port 3389 to the internal IP address(192.168.x.x) of the windows machine you are trying to access. To check if a port is open on your router, visit canyouseeme and enter the port number in the port field. If the check fails check your router settings and retry. If you have a firewall or anti-virus protection you need to configure it to allow specific port traffic.
To forward a port on Beetel 220Bx
Step1: Open a web browser, enter the IP Address of the router in the address bar (default is 192.168.1.1). It will ask for a user name and password (Default username is admin, and the password is password).
Step2: Goto Advance setup > NAT > Virtual Servers > Click Add
Step3: Select Customized service: and enter Remote Desktop
Step4: Select Protocol: as TCP/UDP
Step5: External port: 3389 and Internal port: 3389
Step6: Type in the Internal server IP address: to which you want to forward this port to like in this case port 3389 is forwarded to 192.168.1.4 (see image below)
Step7: Click Apply, check if the port is properly forwarded by visiting canyouseeme
To forward ports on other routers visit Portforward.com
