Server not found

Firefox can't find the server at login.facebook.com.

    *   Check the address for typing errors such as
          ww.example.com instead of
          www.example.com

    *   If you are unable to load any pages, check your computer's network
          connection.

    *   If your computer or network is protected by a firewall or proxy, make sure
          that Firefox is permitted to access the Web.

是前几天的事，当时无论如何调整，ip都是当地的

我的可以啊，装了Safari，chrome，Firefox，ie8，opera只有最后一个不行