If you have a Mac OS system where you have inserted/removed network cards multiple times, Mac OS will often generate new network names each time you do this so you may see your network ports have interface names with higher number/ordinals. For example.
You may start out with en0, en1, en2, en3, en4 and en5 shown by the "ifconfig" command but after you have performed multiple network card changes, you may see en0, en1, en2, en9, en10, en11 and so on. In order to get Mac OS to re-order the interface numbers back to the original list, do the following:
-Remove the Network preferences file(s) from Mac OS and let it re-create all interfaces on the next reboot.
It will require that you redefine all IP addressing for all the interfaces over again using the System Preferences Network GUI so make sure you have all the information to do so:
sudo mv /Library/Preferences/SystemConfiguration/NetworkInterfaces.plist /
sudo mv /Library/Preferences/SystemConfiguration/preferences.plist /
The above 2 commands move the current preference files to / which is the root filesystem...in case you need to put them back.
-Now reboot your system and Mac OS will re-generate the network interface names starting with en0. You can now use the System Preferences Network GUI to define the networks.Back to Apple OSX 10.6