Second Ethernet

[Axel IS Main]

I'm trying to configure a second ethernet adapter in my fedora computer. 
The original is connected to my internet network, the second will go to 
a cable modem and then out to the internet. The problem I'm having is 
the new adapter won't pick up an IP from the cable DHCP. I've checked 
and the cable modem is definitely looking at the mac of the new nic. 
Another thing I'm noticing is that this machine is configuring both nics 
to the same interrupt. Is it possible that this is what is causing the 
problem?

Nick