A MAC address (Media Access Control) is a unique identifier assigned to a network device’s NIC (Network Interface Card). It’s also known as a Physical Address, Hardware Address, or Burnt-in-Address. The MAC address is represented in hexadecimal formats, such as 00:0a:95:9d:67:16, and is 12 digits long (48 bits). The first 24 bits are for the OUI (Organization Unique Identifier) and the remaining 24 bits are vendor-specific. The MAC address is embedded in the NIC by the device’s manufacturer and cannot be changed. It operates at the data link layer of the OSI model and is used by the ARP protocol to associate a logical address with a physical or MAC address.