When you’re connected to internet (Wide Area Network or simply WAN), an external IP address is allotted to your router. This IP represents all computers connected to that router. When an external computer which is not the part of that system tries to communicate with any of the computers, it first communicates with router because the IP address was assigned to router not to a specific PC. If there are more than one PCs in that system, router will be unable to understand whom it has to send incoming data. Port forwarding simply helps the router to choose the right computer to communicate with. A port is assigned to that specific computer and router sends data to that specific port only.
See the screen shot below:
Steps to forward a port:
1- Open any web browser like Chrome, Mozilla, IE.
2- Write 192.168.1.1 in URL box and press enter. It will ask for username and password.
By default router username and password is admin or Admin. If you don’t know then simply contact your ISP. See the screen shot below:
4- Click on Login. Goto Advance Setup then NAT then Virtual Servers.
5- Click on Add button. Choose a Service/Application Name (It can be any name etc. my app, portforward). Enter the IP address of that computer whom you have to assign a port. To check the IP address of that computer please visit this article. Enter the same port in External Port Start, External Port End, Internal Port Start and Internal Port End. Choose Protocol (TCP is better). Finally click on Apply or Save button.
Your port is now opened and forwarded. See the screen shot below:
Note: Above method is explained on the basis of PTCL router. Your router settings can differ from PTCL router settings. But the basic functions like NAT and Virtual Servers are present in all broadband routers.
In case you have any questions or problems in this process feel free to leave a comment.