post the output from the following (with both of your cards installed)
lsmod (as root)
or
cat /proc/modules (as anybody)
and
lspci (as root)

I ran into a similar problem with my install... One network card was recognized by RH8, one was not (the onboard NIC). After downloading and installing the drivers, and rebooting, I only had my new NIC, but couldn't find the old one.

Log in as root, and choose your favorite editor to edit "/etc/modules.conf".
You'll see a couple of lines that say things like "alias eth0 realtek" or something. You should have one line linking eht0 to your NIC (or cable modem), and on line linking eht1 to your cable modem (or NIC). Both of these lines probably say "eth0", so change on of them to "eth1". Also, one of these lines is probably commented out with a "#". Remove the "#". Now, in GNOME, from the menu run System Settings--> Network. Make sure you have two NICs listed. If you need to add one, use the add button to add it. Make sure you look at which one is eth0 and which is eth1. These must be the same as in your modules.conf file. Set your settings for each NIC. My guess is that you want the cable modem to activate on boot, with DHCP enabled, and from here you can also set your hostname.

Go ahead and reboot... I suspect you'll be able to get it working from here. If not, let me know. Maybe there's something I missed (certainly wouldn't be a first!).

Scott

Ill give a try...

I have 1 NIC (RTL8139) and a USB cable modem.
If I unplug my usb cable modem, my nic is eth0 with a fixed ip address (192.169.0.1) and everythings working fine, but if I plug my usb cable modem, my eth0 is still my NIC with 192.168.0.1 and has the MAC address of my cable modem.

It seems that my usb cable modem try to assign eth0 as my cable modem...

If i go to system preferences, network (GUI), it tells me that the alias of eth0 in my modules.conf is 8139too (my NIC) and the module that is currently loaded is CDCEther (my usb cable modem)...

Anyone knows how to solve my problem?

I would greatly appreciate because I had this problem for the last 4 months...

Thanks

I will go out on a limb here since I am no expert. However, I have had excellent results doing the following on my RH7.2 installations (shut down before adding or removing cards!!):

1. Remove all nics from your machine and boot. Kudzu will see that there are no cards and ask you what to do. Select erase configuration for both cards.

2. Install ONE card and boot. Kudzu will see it and ask if you want to migrate or set up networking. Choose set up networking. Configure card either for connection to the modem or for your internal network.

3. Shut down again and add the second card. Boot and Kudzu will see the second card. Again choose set up networking. Now you can configure this new card and everything should work.

Hope this helps.

I have yet to reboot, but I have had the same issue - I changed it by logging in as root, and setting the hostname with 'hostname <name of host>'. I will let you know if it doesn't work for me.. - the issue isn't due to your hardware or software being configured incorrectly - well, sort of - but not due to bad stuff - it's just that when your DHCP server gives your Cable Modem a name the only name it can come up with after DHCP has occurred is the MAC address for your card/cable modem. I have a similar setup and my LAN that connects to the Internet is the name of my host with the MAC address spec.. I might have someone blow holes all through my theory because it really is just a theory - I'll let you know if the hostname thing worked out for me..

The hostname is now my special 123Penguins (I have kids and that is an inside joke). The gnome manager still says that it can't find the host 123Penguins in the /etc/hosts file - adding that... and restarting should tell me if it worked...

I am done with that fun issue - I have tried 8.0 before but it crashes (as well as the Knoppix distro in random spots - it might be a video setting from before so I hope that changes this time) so I have had this issue twice now - the hosts file worked great - I know that there was some other way that I fixed this before too - so, first change your hostname using the hostname command - then make sure that your hostname for the NIC that uses DHCP is set to the name you want (may not be necessary - need to reboot to find out though..) and then make sure the name you want to refer to your computer as is in the hosts file..
127.0.0.1 localhost.localdomain localhost othername
or just add a new line
127.0.0.1 othername

hope this helps someone..

I found how to solve the hostname problem and I also found the problem with the interface conflict. And now everythings working well!!

After 4 months I finally found how to solve the problem with cable modem and Linux!!

How?
Cause I'm having something like this in RH 9.0

I simply edited my modules.conf
I only changed my eth0 for eth0 and eth1 for eth0!

to start, this is my network layout:
coax --> cable modem -> usb cable -> redhat 9.0

it works with windows xp. but with redhat it doesn't work. i just installed redhat and started it. i was never able to connect. this is the first time. any comments and pointers are appreciated. thanks. ari