Many times I have needed to change network cards on a linux box, or I move a virtual machine and the nic mapping changes from eth0 to eth1. Thankfully it is really easy to fix if you just know where to look.

sudo vi /etc/udev/rules.d/70-persistent-net.rules

My example shows the two cards. The top one is the old card – no longer installed; the bottom one the new.

What you do is delete the top card from the list, and change the mapping on the bottom card to eth0.

:wq to save and exit and reboot. Congratulations! You have changed the network card mapping.