weird device names like devXXXXX with ifconfig on Fedora/RHEL

We had a machine that would keep coming up with devXXXXX where XXXXX is a seemingly random number. We tried ifrename to no avail, modprobe -r didn't help, modules.conf didn't help. It turned out that the HWADDR line in the ifcfg-ethX file was wrong. After fixing the line we were able to do ifup ethX and the devXXXXX went away.