In networking, Media Access Control (MAC) spoofing means taking on the identity of another computer, and can be done for both malicious and benign reasons. It can be used to obscure the true MAC address or gain access to networks by using a MAC address that is identifiable by the network.
Though network interface controllers (NICs) are assigned permanent MAC addresses when manufactured, there are tools that can be used to make computers believe that a NIC has a different MAC address. MAC addresses are assigned per hardware at the factory, and each piece of hardware has a unique MAC address. All network interface controllers (NICs) have unique 48-bit MAC addresses. These addresses are used to identify different devices in order to connect with one another on a local area network.