Can I change my computer's MAC address?
Answer: The MAC address is a unique identifier given to each network card (NIC). It typically looks something like "00:1a:2b:3c:4d:5e". Since this address is physically printed or "burned in" the card, it cannot be changed.
The hardware MAC address is also known as the "universal address." A computer may also have a "local address," which is typically copied from the network card's hardware address. This is the address routers and switches often use to identify computers on the network. Since the the local address is stored in software, it can be changed. Changing the local MAC address is sometimes called "MAC address spoofing" and may be used to alter the way your machine is seen on a network.
Local MAC addresses can be changed on Windows, Macintosh, and Unix systems.
Windows users can change the local MAC address of some network cards by opening the Network Connections control panel, right-clicking the current network connection, and selecting "Properties". When the Properties window opens, press the "Configure..." button, click the Advanced tab, and select the "Locally Administered Address" option. You can then enter a new MAC address in the "Value" field. Advanced users can also change the local MAC address by manually editing the Windows registry. Once the MAC address has been modified, you will need to restart your computer for the changes to take effect.
Macintosh users can change their local MAC address by running ifconfig in the Terminal application or using a program like ChangeMAC.
Unix users can also change their local MAC address using the ifconfig command (after all, Mac OS X is based on Unix).
IMPORTANT: If you are on a school or business network, changing your MAC address may violate the network usage policy. Therefore, make sure to check the network guidelines before changing your computer's local MAC address.