Thank you Cem_UPC.
I did restart my modem and doing following configuration. I am still not lukky enough to achieve what I want.
In “Port Forwarding” menu, I see a possibility to internal IP, internal port and external port. Where / how to I mention the external (public IP) ?
My requirement is.. when a public IP and port are given in internet (outside my router network), it should be redirected to my internal ip and port. There is a web server running in my local. I have a public IP with me.
Do you have any step by step guide to achieve it. Thank you in advance.