This works on Redhat and Fedora, so should work on centos:
configure all your /etc/sysconfig/network-scripts/ifcfg-eth* as explained in http://www.centos.org/docs/2/rhl-rg-...rkscripts.html
You should also mention the GATEWAY in here (the default route to the outside world) as explained here: http://www.centos.org/docs/5/html/De...nterfaces.html
then restart the network (/etc/init.d/network restart)
then in a terminal, run this:
tail -f /var/log/messages
then unplug and plug back each network cable of the server one by one. You should see a message appear with the ethernet interface name. Then you can add stickers on the ports and cables so you don't need to do that over and over.