I'm a brand new Linux user, and I'm having difficulty setting up a connection to my ISP. My system configuration:

ECS K7S5A motherboard (SiS chipset)
Integrated sound and NIC
Duron 950
TNT AGP card
20 GB Maxtor 5400 rpm HD
256 MB Crucial DDR SDRAM (PC2100)
300 W PSU

I have an ADSL connection to Earthlink through a Linksys BEFSR41 4-port router; currently I have two other computers, one running Win98SE, one running WinXP, successfully connected to the internet through it.

I've installed Mandrake 8.1, but at the stage where the configuration wizard tries to set up a network connection, I can't seem to make it work. Doesn't seem to matter whether I specify to connect via ADSL or via LAN. The configuration proceeds with apparent success, but the connection then fails.

Same thing happens if I try to configure it from the KDE GUI.

Obviously I'm doing something wrong, and I need some coaching.