Change MAC address

Sometimes, you may need to change or clone the MAC address for some reasons, bellow are instructions on how to change MAC address under both Windows and Mac OS.

Change MAC address under Windows

Under Windows XP, the MAC address can be changed in the Ethernet adapter's Properties menu, in the Advanced tab, as "MAC Address", "Locally Administered Address", "Ethernet Address" or "Network Address". You can discover your MAC address here and than change it. The exact name depends on the Ethernet driver used.
However, not all drivers support changing the MAC address in this way.

A better way to change MAC address - requiring Administrative User Rights - is to pass over the System Registry Keys under HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlClass{4D36E972-E325-11CE-BFC1-08002BE10318}. Here settings for each network interface can be found. The contents of the string value called 'NetworkAddress' will be used to set the MAC address of the adapter when it is enabled.

Note: to check your MAC address easily on a Windows XP box, go to Run, type CMD, then type "ipconfig /all" without quotation in the command prompt. The number under physical address is the MAC address. If multiple IP are displayed, you should look under the label "Ethernet adapter x", where x is the name of your connection (which is Local Area Connection by default).

Change MAC address under Mac OS X

Under Mac OS X, the MAC address can be altered in a fashion similar to the Linux and FreeBSD methods:
sudo ifconfig en0 lladdr 00:01:02:03:04:05
or
sudo ifconfig en0 ether 00:01:02:03:04:05

This must be done as the superuser and only works for the computer's ethernet card.