It can be useful to be able to quickly generate a Random MAC address with virtual environments like KVM. The following is a method which always sets the first octet as 00 which can be set as required.
$ MACAddress=$(dd if=/dev/urandom bs=1024 count=1 2>/dev/null|md5sum|sed 's/^\(..\)\(..\)\(..\)\(..\)\(..\)\(..\).*$/00:\2:\3:\4:\5:\6/')
$ echo $MACAddress
00:6c:39:6d:32:c4
