Missing eth0

You might face issues that when you restart / clone / change nics of your linux box and run the ifconfig command checking interfaces, you will see eth0 missing.

The reason of this is that the old MAC address is cached by the network configurations in some distribution on linux..

The file which has the cached entry is  : /etc/udev/rules.d/70-persistent-net.rules
You can follow the below 2 methods to fix this problem.

  1. Edit the above file, remove the old entry of "eth0" , change "eth1" reference to "eth0"
  2. Move this file in /tmp as a backup, and reboot the system. [ You have a backup, incase this doesn't work,playing safe ]