What is a MAC Address?

• A. A type of encryption key
• B. A unique identifying value assigned by manufacturers to network adapters and NICs
• C. A global network address assigned by ISPs
• D. A protocol for address resolution

Answer: (C)

A MAC address is a unique hardware identifier assigned by the device manufacturer to a network interface card. It identifies that specific NIC on the local network segment and is used at the data link layer to deliver frames to the correct device. Typically written as six pairs of hexadecimal digits, it’s a fixed identifier baked into the hardware (though it can sometimes be spoofed or changed in software).

This isn’t an encryption key, and it isn’t a global network address assigned by an ISP. It also isn’t a protocol for address resolution. The role of a MAC address is to provide a stable hardware address for local-frame delivery, while IP addresses, assigned by ISPs, handle routing between networks. On a LAN, devices use ARP to map an IP address to the appropriate MAC address so that frames can reach the correct NIC.