eth0 has different mac address than expected

I have encountered this before. I managed to fix it by editing
the /etc/sysconfig/network-scripts/ifcfg-eth0 file, and removing all
lines that have a defined MAC address. ie the lines :

MACADDR=

or
HWADDR=

Also check that lsmod shows the device's kernel module loaded ok - check
the /etc/modprobe.conf file for alias eth0 , and see if
that module is loaded ok in lsmod.