How to configure Dataone modem with Dlink DIR 600 wifi router


I am using BSNL ADSL broadband internet. My ADSL modem is Siemens C2110. I want to configure it with D-Link wifi router Model is DIR 600. To some extent I successfully configured the modem with wifi router but I am facing few problem. The problem is that I am not able to open all the websites like Yahoo, rediff, Lycos, sify, etc are not open whereas gmail, google, orkut etc gets open. When I use the modem without wifi router, all websites opens very easily. Some one plz help me