I found some info on knoppix network setup here:
http://www.knoppix.net/forum/viewtopic.php?p=38129
there is a /etc/network/interfaces example, you can remove the
address line and change static to dhcp to use dhcp instead of static
IP address.
You can use similar setup for eth0 and eth1, but you must have both interfaces on different networks if you want to use them at the same time.
Another URL with examples:
http://www.physics.ubc.ca/mbelab/com...tallation.html
This is the first I have heard of HomePNA, what is the make and model of the USB device?