If you are on local computer, to change mac address you need to:
ifconfig eth0 hw ether xx:xx:xx_mac_address ifup eth0
Attention, you cannot do this when remotely connected, because "ifdown eth0" will disable nic and this mean no more network connection. You can try to change mac address remotely (i've succeed to) with this simple trick. (focus-pokus) :)
Make one file 'nicmac.sh' with: #!/usr/bin/env bash ifdown eth0 ifconfig eth0 hw ether xx:xx:xx_mac_address # example: 50:aa:49:99:4a:00 ifup eth0 #--End of file 'nicmac.sh'