because of a hardware change (you may have used a different ethernet
device & then removed it) your original eth0 gets it's name changed
to eth1, or if using a number of devices the names get changed around
out of the order in which you prefer to see them. This can be annoying
and you may want to change the names back. You can do this by altering
two files in your system.
First go into /etc/udev/rules.d/
Vi and Vim commands
$ sudo vi /etc/udev/rules.d/70-persistent-net.rules
First establish if there are any unused devices still present and delete the entry, remembering to rename or remove the corresponding ifcfg file in /etc/sysconfig/network-scripts.
For example, above I want to delete the old eth0 entry and then find the eth1 device I am still using but wish to rename and change the NAME parameter from eth1 back to eth0.
So make your adjustments or removals in 70-persistent-net.rules and then go to /etc/sysconfig/network-scripts where you will alter and rename the ifcfg-eth1 file.
$ sudo vi /etc/sysconfig/network-scripts/ifcfg-eth1
|eth1 renamed to eth0|
Change the parameters to suit, DEVICE="eth0" etc, not forgetting the HWADDR, which is the Mac address from the ifconfig or dmesg command. Then you can rename it as in the examples above where you can see the that the Hwaddr for eth0 in the lower image is the same as the Hwaddr for the renamed eth1 from the top image.
$ sudo mv /etc/sysconfig/network-scripts/ifcfg-eth1 /etc/sysconfig/network-scripts/ifcfg-eth0
Or write a new file completely with contents similar to below
Which are typical parameters for someone using a static IP address on a wired ethernet card. Finally, issue the command
$ sudo service network restart
Or reboot your system to enable the new named device.
Labels: Centos 6, change back eth1, eth0, rename device, RHEL