Quote Originally Posted by carpie
Through windows, the driver is for HP EN1207D-TX PCI 10/100 Fast Ethernet Adapter
I posted on this a while back, so I'll just quote myself here:

This card uses a MX EN5038A1 chip, which (from a quick scan of Google) seems to be VERY poorly supported under ANY version of Linux. Shame on HP (even their own tech support admits it won't work under Linux). I had the same problem with an SMC TX-1211 card. You would think that brand-name hardware would "just work."

What I wound up doing was getting another network interface card (NIC). Fortunately, Knoppix LOVES the Realtek RTL8139 chip, and there are at least 2 common cards that use it: the D-Link DFE-530TX+ and the Encore ENL832-TX+. The D-Link card sells for about $12 (I got it free with my DSL kit), I bought the Encore card for $8. Both work equally well with my DSL modem and Knoppix; I would recommend them to anyone using Knoppix; it's my new "default" NIC. A bonus: the Encore drivers for Windows are newer.

Since then, I have seen other cards with this same Realtek chip for even less, and they work just as well.