A MAC (Machine Access Control) Address is a manufacturer-assigned unique identifier attached to most network adapters - network interface cards (NICs). The MAC address is unique as it acts like a name for the adapter and is addressable by layer 2 network protocols.
Since the MAC address is assigned one time by the manufacturer and attached to the device, you cannot use it to determine a geographic location or proximity like you can use an IP address for.
The standard format for MAC-48 addresses is six groups of two hexadecimal digits separated by a hyphen (-), e.g. 08-34-45-68-88-ab. It is also common to see the MAC address separate by colons (:), e.g. 08:34:45:68:88:ab. You may also see it in three groups of four hexadecimal digits separated by dots (.), e.g. 0834.4568.88ab.
The MAC address is formed using an organizationally unique identifier (OUI), the first three octets, followed by three octets to form a unique address. The last three can be derived in any way the manufacturer chooses - as long as it produces unique addresses.
The MAC address assigned by the manufacturer is known as the universally assigned address. A network administrator could assign their own MAC address, if they do, it is known as a locally assigned address.
