I'm using USB 3G Dongle for Internet. Previously I was using Tata Docomo (India) as provider, and the Internet was working fine. Now I've changed to BSNL, but I'm unable to connect to the Internet on Ubuntu. However, I've checked access point settings and other configuration which are required for BSNL, and it is working fine with same Dongle on Windows 7. Also, I'm able to connect Internet with other providers on Ubuntu, but problem persists only with Ubuntu. The access point for BSNL in my region is bsnlnet. In fact I configure the Dongle with BSNL using default Network Configuration wizard that pops up when USB Dongle is attached.

When Dongle is attached and configured with BSNL, I can see network strength in Messaging menu, in Mobile Broadband category, of Ubuntu (note: my network icon still shows "not connected" status). And when I try to use the connection that I've created, it fails to connect. So far, I tried using Sakis3g script that I came up with while wandering over this issue on other forums, it didn't worked either. I also made sure that there are no special configuration made for BSNL on my Windows 7 installation, and still it is working fine there, the problem is only with Ubuntu.

How can I fix it?