[SOLVED] How can I get CentOS to recognize the nic (eth0) after changing the mother board?

How can I get CentOS to recognize the nic (eth0) after changing the mother board?

Both motherboards were Supermicro, apparently with different nic's so it seems the driver doesn't match.

What's the easiest way to get it to recognize the new nic without reinstalling the OS?

the most basic thing would be to use lspci to find out what nic is there and then use modprobe to load the kernel module for that device.

I have noticed on my desktop running cent 7 that in the gui there is an option to "create" a network device.

Most likely udev is naming your nic eth1. You can check dmesg, and grep for "eth". I suspect you'll find that a different ethX is configured. If so:

There must be a file called 70-persistent-net.rules. Most likely it is in /etc/udev/rules.d. But that is Debian, Centos might be different.

Anyway, open that file and delete the lines which describe the hardware properties of eth0 and eth1. Reboot.

jlinkels

Centos7 renamed my nick to 'enp7s4' Why can we not stick to the basic here?

Centos 7 didn't rename it to enp7s4. Red Hat followed BSD naming conventions to more easily help advanced users find what nic they really are using rather than an arbitrary enX number. My guess is that most other distro's will eventually follow this naming.

I'd also suggest ip command or ifconfig -a to find out what you have. I too agree that it may be named differently based on the motherboard change.

Fedoara, RedHat and clones are stinkers and have been stinkers when cloning or moving to other hardware because they way it located nic's before. There is some file you have to edit if the name is wrong to get back to eth0.

Now, if your nic isn't fully supported then you either need to do one or more of the following. Blacklist driver, add in driver, use ndiswrapper to run windows driver.

CentOS is the same. If you delete the /etc/udev/rules.d/70-persistent-net.rules and remove the MAC address from the ifcfg-eth0 file networking should be reconfigured when you reboot.

lazydog
http://en.wikipedia.org/wiki/Consist..._Device_Naming

You might check the configuration files. Those generated by the GUI tend to have the MAC address AND a UUID included. And these alone will prevent the network device from being recognized.

If the file /etc/sysconfig/network-scripts/ifcfg-<interface> have an entry "HWADDR=" and/or "UUID="
you would have a problem. I just commented out the "UUID=" entry (using #) and then replace the MAC address with that of the new entry.

No problems after that. In the case of my SuperMicro motherboard, the system named the interface enp6s0 and enp6s1 (I'm using Fedora 21).

I had no need to change drivers - the system recognized them appropriately.

Originally Posted by michaelk CentOS is the same. If you delete the /etc/udev/rules.d/70-persistent-net.rules and remove the MAC address from the ifcfg-eth0 file networking should be reconfigured when you reboot. lazydog http://en.wikipedia.org/wiki/Consist..._Device_Naming

That was it thanks, I move that file out of rules.d and it recreated it upon reboot with the new MAC addresses

Originally Posted by michaelk lazydog http://en.wikipedia.org/wiki/Consist..._Device_Naming

I never had an issue with the old way. Got my order by placing the MAC address in the config files. The new way make you have to think about what port is where. Besides it is easier to remember eth0 instead of enp7s4 (had to look it up).