How to start [Configure] BSNL Broadband connection on Ubuntu
Go to your Network control panel.
Follow steps : Taskbar >> System >> Administration >> Network.
Then click on the Unlock button and then it will ask for Administrative password, Enter your Password. and click Authenticate so that it will unlock the locked features.
Click on Wired connection and then its properties, it will show you “Connection setting tab” select “Automatic configuration (DHCP)” from the list and click OK.
Select Point to Point connection, and go to its properties. It will pop up the pppo properties.
Check the “Enable this connection”, and select “PPPoE connection type” and Enter the account data (Username and Password)in specified boxes,
Go to Modem tab from same Window, select the Ethernet interface (Generally the eth0)
Go to option tab select all check boxes. and then OK. and close.
Now everytime you want to connect to net, just click on LAN Icon on taskbar and go to Dial Up connections and click on Connect to pppOe via modem and get connectiviy.
So now just start your Firefox and start browsing the internet from your Ubuntu.
Note: This guide is for LAN connection only, and not for the USB connections as many modem manufacturer doesnt provide drivers for Linux versions.