port forwarding on bsnl nokia siemens 1600 residential router Sl2- 141 type B

The virtual servers page is even hidden in 192.168.1.1/main.html
you can access the page by going to 
http://192.168.1.1/scvrtsrv.cmd?action=view

more tips for the modem

192.168.1.1/scprttrg.cmd?action=view for port triggering

192.168.1.1/scdmz.html for dmz