How to Change your Mac / Hardware Address in Kali Linux / Backtrack

Macchanger is a tool already available in Kali Linux or Backtrack.  It lets you change the hardware address pertaining to a particular interface on your machine. For instance, as eth0 or wlan0 are the interfaces for wired and wireless connection respectively, here’s how you would use it:

Here, the option ‘r’ is used to tell macchanger to use a ‘random’ MAC address. The option ‘A’ is used to set the random vendor MAC of any kind, while ‘a’ is used to set the random vendor MAC of the same kind.

You can also specify the MAC address that you want to use by using the option ’m’ as shown in the figure.

In case you want your machine to acquire a random MAC address every time you restart the machine, you can do so by storing the following command in the ‘/etc/network/interfaces’ file:

pre-up ifconfig eth0 hw ether 00:00:00:00:00:00

Here, the MAC address 00:00:00:00:00:00 will be allocated to your machine each time you restart it.

Update: If you get an error while you are trying to spoof your MAC address using macchanger, it is probably because you are trying to change the hardware address of that interface while it is ‘up’. This is similar to trying to change a car’s tire while it is in motion–maybe not the best example, but you get the idea. You need to put the interface ‘down’ first. Then change the hardware address using macchanger, and then bring it ‘up’ again.

ifconfig wlan0 down  
macchanger -r wlan0  
ifconfig wlan0 up