How unique is a MAC Address?

Mac Address in CMD box

While using a MAC address to identify a couple computers to permit access to a network I wondered to myself how unique is a MAC address and who regulates it?

Lets me first go over what a MAC address is and what it’s purpose is.

Media Access Control address (otherwise known as a MAC Address) is a unique identifier that is assigned to most network interface cards or network adapters. These address’s are placed on the device by the manufacturer and usually encodes the manufacturers identification number. It is also known as a hardware address, physical address, or adapter address.

An example of a MAC address is: 00-22-64-99-54-2B this 6 pair of characters allows for a 48-bit address space containing potentially 248 or 281,474,976,710,656 combination’s for mac addresses.

To simply answer the question a MAC address is excruciatingly unique. Everything is controlled by the Institute of Electrical and Electronics Engineers (IEEE)