Sorry, I seem to be asking the same question as a lot of people, but hours of surfing the forum haven't helped.
I'm running WinXP and Knoppix via bootable cd, and am having no luck getting my modem (A Terayon TJ 71x) to work.
This is what I'm doing right now, with "sudo netcardconfig":
ip = ipconfig "IP Address"
Default gateway = ipconfig "Default Gateway" (Imagine that!)
Nameserver = ipconfig DNS Servers (?)
Network Mask = ipconfig Subnet mask (?)
Broadcast address = I have no idea what this is.

This works a bit better than just entering the ip and leaving defaults (no network unreachable error within the netcardconfig thing) but it still can't connect to a remote ip.

If you have any ideas about a new direction to explore with this or think that any other information I can give you would be usefull, please do tell.

lspci sez:
Ethernet Controller: National Semiconductor Corporation DP83815 (MacPhyter)
Subsystem: Hewlett-Packard Company: Unknown device 0024
Flags: bus master, medium deusel, latency 90, IRQ 11
I/O ports at 8c00 [size=256]
Memory at d000a000 (32-bit non-prefetchable) [size=4k]
Expansion ROM at <unassigned> [disabled] [size=64k]
Capabilities [40] Power Management Version 2

It may or may not be helpful to note that the activity lights on the modem and the ethernet jack indicate swellness, despite their failure to operate.

Thanks in advance.

ED: My ISP uses dynamic IP assignment only.