How to change your MAC Addresses

$ sudo gedit /etc/network/interfaces

add the hwaddress line under the apposite device - for example:

auto eth0
#iface eth0 inet dhcp
hwaddress ether UR:MA:CA:DD:RE:SS


(ether is the type of device, according to ifconfig - "Link encap:Ethernet")


to restart / stop /start networking:

$ sudo /etc/init.d/networking restart
$ sudo /etc/init.d/networking stop
$ sudo /etc/init.d/networking start