Here's some stuff I posted in an earlier thread (11 earlier threads, actually
):
1. Check the screen output at bootup. If the NIC is being properly initialized, you should see a line that says: "Bringing up eth0- O.K." If you see "failed" or "delaying" instead, you've got problems (see #3).
2. Assuming the NIC comes up, you can do the configuration with the graphical configuration tools linuxconf or netconf. Click on Basic host information-> Adaptor 1. From there, select eth0 as the device, choose the tulip driver from the drop-down list of kernel modules, and enable the device. Then either choose DHCP (if you're using it), or enter your IP information manually. After that, fill in your DNS and gateway/routing info under the appropriate sections.
Update:: Redhat stopped including linuxconf and netconf as of version 7. I'm not familiar with their current config utilities.
3. If you get a failure on bootup, you may have a resource conflict with another device. Try turning off Plug-N-Play support in your BIOS, it can cause conflicts with some cards.
4. As root, type "lspci" and verify that your NIC is being recognized. Type "cat /proc/interrupts" and make sure your NIC's IRQ isn't conflicting with another device. Type "cat /proc/ioports" and check the address ranges for conflicts. If you have resource conflicts, you can try rearranging the slot order of your PCI cards.
5. Type ifconfig. There should be stats for the loopback device (lo) and eth0. Verify that the IP infomation for eth0 is correct, and note the IRQ/base address information. If eth0 doesn't show up, type ifconfig -a. The -a option tells ifconfig to report on all interface, regardless of whether they are active or not.
6. If you get card recognized, but the module isn't loading, try to load it manually by typing "insmod tulip". After that, type "lsmod" to list all loaded modules; the tulip module should show up there.
7. You can then assign the NIC a static IP (if you need to) by typing "ifconfig eth0 xxx.xxx.xxx.xxx", where xxx.xxx.xxx.xxx is your IP address.
8. Look in /etc/conf.modules (/etc/modules.conf in some distros/versions for the line: alias eth0 tulip.
If it doesn't exist, and lsmod did not list the tulip driver as being loaded, add the line to the file.
If none of the above does the trick, tell us the results you get. Also (important), tells us what distro you're using.