As you don't mention what distro you are using or whether there's any network manager managing your interfaces the best answer you're going to get is:
Check whatever way you're configuring your interfaces, you may find that in the config files there's a hardware address mentioned, maybe something like
Code:
HWADDR=XX:YY:ZZ:AA:BB:CC
These are how the config files are matched to the particular hardware interface. Change them so that your eth0 / eth1 / ethx configs match the relevant physical interface.
