This operation requires root privileges. Do the following
# macchanger -s eth0
You need yo turn down the interface before changin its MAC address change. Use ifconfig command to turn off your network interface. Remember to have root privileges otherwise you cannot run ifconfig:
# ifconfig eth0 down
If the following error message appears you have most likely failed to turn off your network interface:
ERROR: Can't change MAC: interface up or not permission: Cannot assign requested address
Now, its time to change network card’s hardware MAC address to some random hexadecimal numbers:
# macchanger -r eth0
Bring your network interface up and display your new MAC addres:
# ifconfig eth0 up # macchanger -s eth0