Anyone networked on AT&T broadband?

Has does anyone have machine sucsessfully connected to AT&T via a hub connected to their RCA Cable modem?

I am having a real hard time gewtting connected and I am not sure if it is my Network card or their network will not let my LInux box connect.

I will give further details if I CAN hook to ATT.

Thanks.... And I am kind of a noob with Linux but the Network is the only thing giving me problems