Hi friends…i was overwhelmed by the response i got for my first post on Ubuntu/linux.My college promotes open source at the highest level and we are lucky to have mentors like Vipin Sir & Avinash Joshi to lead the FOSS club in our campus.Yesterday Arvind asked me to share the cmd-line procedure to connect to broadband.The GUI didn’t work for me and that forced me to look for a cmd-line version.
I went through a lot of posts on other blogs and linux forrums,each with their own solutions….but only one worked for me.I think the following process is specific for a DSL (Digital Subscriber Line) modem where you need a username and password to connect to the internet.
Here’s how you do it:
1.Open terminal.
2.type
$ sudo pppoeconf
3.Hit Enter until it asks for username and password.Enter your username and password when prompted.(Note: be careful in differentiating which username & password is aked;enter the administrative p/w at the beginning & thereafter you would only need the username and p/w provided by your ISP.)
4.Once configured go to terminal and type
$sudo pon dsl-provider
(sudo pon to power ‘on’ the connection )
5.To disconnect,open terminal and type
$sudo poff dsl-provider
(sudo poff to power ‘off’ ‘ the connection )
This worked flawlessly for me.Hope it do the same for you.Enjoy the web!
LAA : L'Aventure Ambiguë 
Well the same thing is there in network manager too. except it’s a click to on or off. still this is good: i didn’t know this. awesome dude. thanks for the info.
to do this graphically just go to network manager and go to “dsl” tab give MAC address there(you can get it by typing ipconfig) and then give provider name(if it is BSNL give “dataone”)and username and passwd given by your provider
regards,
dilip