2 or more nic cards

I have setup one nic card on a freshly installed redhat linux, and it work fine as an eth0. I would like to ask if say i would add another nic card of the same brand, what do i need to configure? Do i just installed the card and it will automatically give eth1 and i will just have to add its ip address?

and what if the nic card is not supported on the redhat package, but the driver can be downloaded at its support site, how can i configure to work properly as a second nic card on the linux box?

Who is Participating?
vsamtaniConnect With a Mentor Commented:
If you want to install a new network card, there are a couple of steps you have to go through. They're not very hard. Depending on what version of Redhat you have, it may do them automatically for you, but here is how to do them manually (and by implication, how to correct any mistakes that an automatic install might make).

First, you need to work out what driver the ethernet card needs.

First, have a look to see what nic drivers your redhat already has. Look in /lib/modules/, and in there will be a directory with a name like 2.2.12-20 or similar (it's the version number of your kernel). Within that directory is a "net" directory, and in there you'll see a number of *.o files. They're all networking drivers of various kinds - for example, 3c59x.o is the driver for the 3com 3c59x series. If you get a card that has a driver already in here, life will be easier. If not, you'll have to install the driver yourself, following the instructions of whoever wrote the driver.

If you install an ethernet card with a driver that's already available, you'll have to open up the file /etc/conf.modules. In there, you'll see a line

alias eth0 <something>

The <something> is the driver for your eth0 card. You'll need to add a similar line

alias eth1 <driver-module for the new card>

for example, if you put in a 3com 3c590, the driver-module is 3c59x.o, and you'd put in the line

alias eth1 3c59x

(note that you drop the .o from the end)

If the card you install is non-PCI, you may need to specify the irq and io base. For example, if you put in something like a basic Dlink de-220 card, the driver module for it is ne.o, and you'd have lines :

alias eth1 ne
options ne io=0x300 irq=3

(IO 300 hex, irq 3, clearly)

Save the conf.modules file.

Now look in the /etc/sysconfig/network-scripts directory. You'll see a file called ifcfg-eth0. Open it in a text editor. The first few lines are all you need to worry about, and they are virtually self-explanatory. Change





When you're finished, save the modified file as ifcfg-eth1. Reboot the system, and then try ifconfig to see what comes up. With luck, you'll have a working eth1 network interface....


You will need to configure the new card as well - linuxconf worked for me, or the RH installer makes it really simple since you have a fresh install.  But before you get there, its worth checking that the cards are assigned to differernt IRQs (in your system bios.)  The IRQ problem cost me weeks!

good luck, George
Vijay (vsamtani) has provided an excellent explanation above of the necessary steps.  If you use this method, it should ensure your familiarity with the proper networking config files (which is a *good* thing, if you plan to continue to administer linux systems).

On the other hand, linuxconf will do all of that for you once you have identified the proper driver for your card.  If this config is a one-time deal, and you want to just get it out of the way, then linuxconf will probably be more what you want.

An additional note - if your network card(s) are PCI, and your motherboard BIOS is halfway decent, you generally will not (although there are a few exceptions) have to specify an IO address or an IRQ for your cards.

What kind of ethernet card(s) are you using, BTW?


reytaAuthor Commented:
i am using rtl8029, and the rh6.1 linux detected it at boot...i check /etc/modules.conf and found another eth1 was added...then i edit /etc/sysconfig/network-script/ifcfg-eth0 to desired new ips and saved it as ../ifcfg-eth1 and the reboot.  thanks.
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.