Gmail blocked!

I am not able to open gmail and facebook website. Its showing:
"This domain is blocked
Site blocked. Welcome to Facebook - Log In, Sign Up or Learn More is not allowed on this network."

How come this happen and what shall I do to get rid of this? Pls help.

Sourav

Give more details about your set up.
Modem/router used. Whether problem sudden ? Firewall AV applications used .
. Use different access URL - Get started by using a different URL web address to access Gmail instead of using www.gmail.com.

- http://gmail.com or https://gmail.com
- http://m.gmail.com or https://m.gmail.com
- http://googlemail.com or https://googlemail.com
- http://mail.google.com/mail/x/ or https://mail.google.com/mail/x/

Try through email client. or try tinyurl.com(as proxy )

well, It got ok when I changed my internet protocol settings from openDNS one to google DNS one. Last week I changed my settings to openDNS as advised in the below thread:
http://www.indiabroadband.net/broadb...onnection.html