Sunday, July 5, 2009

Change MAC address in Windows

Although MAC (Memory Address Control) addresses are meant to be permanent, it is possible to change the MAC address reported in the operating system. Changing of a MAC address is sometimes necessary for maintaining privacy when connecting toWI-Fi and for interoperability, and the act is sometimes called “spoofing”.

An Internet Service Provider or ISP generally binds the service to a particular MAC address, meaning that if a network card or a router is changed by the user, the service can no longer be accessed. However, this can be countered by changing the MAC address of the new interface being used.

In Windows, the MAC address can be changed in the property menu of the Ethernet adaptor. The exact name found on the “Advanced” tab depends on the Ethernet driver used and a user may find various names such as “Ethernet Address”, “MAC Address”, “Network Address” or “Locally Administered Address” in the tab. There is a better method than this which requires registry editing permissions. System registry keys that are under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002BE10318} are to be passed over. Network interfaces can be found here and the MAC address of the adaptor is set from the contents of the “Network Address”.

The adaptor can be reset by using acommand line utility offered for free by Microsoft called Devcon. The addresses of all cards, including those that are not changed through the property menu of the adaptor can be changed with the SMAC MAC Address Changer. The new address can be checked by clicking on Run from the Start menu and entering the command module (cmd) followed by typing ‘ipconfig/all’ into the command prompt, which shows the MAC address under the physical address.

All routers do not have the facilities to change the MAC address and the mode of changing varies greatly in those that so. The “clone MAC address” feature in a router helps change the MAC address by obtaining the MAC address of one of the machines present in the network and replacing the current address of the router with the acquired one. Some routers also allow the MAC address to be changed manually.

Using a MAC address as the sole method of identification is not a very good idea seeing that MAC addresses can be altered. Another method, the IEEE 802.1x can be used instead as it is coming up as a standard authentication method for low-level devices.