CENTOS Missing network interface virtual machine move

We had a situation that was in our virtual environment where the network interface disappeared from our centos 6 virtual server.  This happened when we moved the image to a new server, but similar things can happen to users.

Our symptoms were, upon booting, the boot sequence was indicating that the NIC was not found/valid.
When we logged into the console and did an "ifconfig" all it showed was the loopback interface.

Here's what we did to recover the NIC

goto the directory /etc/udev/rules.d/

Delete (or if you prefer, rename) the file 70-persistent-net.rules
Reboot your box.

go back to the directory /etc/udev/rules.d/ and look at the 70-persistent-net.rules file again
" cat 70-persistent-net.rules "

Note both the MAC (hardware) address that should be in this file now, as well as the interface name (more than likely ETH0, but its possible it could be something else)

Goto the directory /etc/sysconfig/network-scripts

Do a directory listing and note the "ifcfg-XXX" files in there.  Assuming there is a file in there that matches the interface name that was in your  70-persistent-net.rules (in our example it is ifcfg-eth0)

Simply edit that file (vi or NANO) and change the HWADDR to be the same as the one in 70-persistent-net.rules

save your changes and reboot.  That should fix the problem.

IF by chance the system is showing a different ifcfg-ethX value than the one in the 70-persistent-net.rules file, make a copy of the original file  “ cp ifcfg-ethORIGINAL ifcfg-ethNEW “ and edit it with the same HWADDR change mentioned above.  Also ensure that the "DEVICE=ETHX" matches the name of both the file you are editing and the ETHX value in 70-persistent-net.rules