> It's also useful for when certain vendors have a software license that looks > at the MAC address in your machine to be able to run. When that vendor > charges 12 times as much for their NIC's with the new software license file, > and you can get by with a $50 replacement NIC and use of the "ifconfig ethX > hw ether <MAC>" commmand, it comes in very useful. You cannot however have > two NICs with the same MAC on the same LAN at one time. You've been able to > manually change the MAC address in IBM's AS/400 stuff for many years now. So basically, changing a NIC's MAC is evil, but other people tend to do even more evil, and sometimes you have to fight evil with evil. ;P