Although the physical MAC address is permanent by design and is assigned to your network card by factory several mechanisms allow the modification, or spoofing of the MAC address that is reported by the operating system. This can be useful if you want to keep your privacy or to ensure interoperability. Some internet service providers bind their service to a specific MAC address; if you change your network card or intend to install a router the service won’t work anymore. Changing the MAC address of the new interface will solve the problem.
Under Linux the MAC address of a network card can be changed by doing the following under a root account.
ifconfig eth0 hw ether 02:01:02:03:04:08
” 02:01:02:03:04:08” being the new assigned mac.
Under Fedora Core 5, and possibly in other Linux distributions, to disable and restart networking, you must stop and start /etc/init.d/network, instead of /etc/init.d/networking. Using the described method your MAC address will revert to original MAC address (hardware MAC) after reboot. So if you want to make the change permanently in Debian you have to add
hwaddress ether 02:01:02:03:04:08
into the appropriate section of /etc/network/interfaces so that the MAC address is set when the network device is started.
You can also use the tool MACChanger to change the MAC address under Linux.