Network adapters come preconfigured from the factory with their own globally unique physical or Media Access Control (MAC) address, which helps them identify themselves when communicating with other networking components. Though you can't change the permanent MAC address actually stored by the network adapter, you can make it provide a different address using your operating system (OS). We'll see how to do this with Windows, Mac OS X, and Linux.
There are a few reasons you might want to simulate another MAC address, including troubleshooting and testing your network. From a security standpoint, it's a good idea to understand the technique, referred to as "MAC spoofing," because hackers also find it useful to get around MAC address filtering. This filtering is used by some network administrators to help control which devices end-users can connect to the network or even as another layer of security against hackers. If nothing else, understanding MAC spoofing will help you demonstrate to yourself or others just how easy it is to change your address and bypass MAC-based security measures.

Changing Your MAC Address in Windows

Before you change the MAC address, you might want to write down the original one. One way to bring it up is to open the Network Connections window, double-click the desired network adapter, and on the Network Connection Status window, click the Details button to look for the Physical Address. Another way is to open a Command Prompt, type ipconfig /all, find the desired Network Connection, and look for the Physical Address.

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