Each NIC (Network Interface Card) has a unique MAC (Media Access Control) address. This applies to all types of network cards, including Ethernet cards and WiFi cards. The MAC address is a six-byte or 12-digit hexadecimal number that is used to uniquely identify a host on a network.

An example of a MAC address is 1F-2E-3D-4C-5B-6A and it falls into the Layer 2 networking protocol of the OSI model. In today's networks, ARP, or Address Resolution Protocol, converts a MAC address to a Layer 3 protocol address, such as an IP address. A MAC address can also be called a physical address. Read my post on how to find your MAC address if you don't know it.

All MAC addresses are hard-coded into a network card and can never be changed. However, you can change or spoof the MAC address in the operating system itself using a few simple tricks.

So why would you want to change your MAC address? Well, there are many reasons, usually related to bypassing some sort of MAC address filter on a modem, router, or firewall. Changing your MAC address can help you get around certain network restrictions by emulating an unrestricted MAC address or spoofing a MAC address that has already been authorized.