MAC Address
A 48-bit hardware address burned into a network interface, used for Layer 2 delivery.
A MAC address is a 48-bit identifier assigned to a network interface card, written as six hexadecimal pairs (e.g., 00:1A:2B:3C:4D:5E). The first three bytes form the Organizationally Unique Identifier (OUI), which identifies the manufacturer. Switches learn MAC addresses by reading source addresses on incoming frames and store them in a MAC address table to forward frames only to the correct port. The critical exam contrast is that MAC addresses operate at Layer 2 for local delivery within a broadcast domain, while IP addresses at Layer 3 handle end-to-end routing. ARP bridges the two by resolving an IP address to a MAC address before a frame can be sent. Although burned into hardware at manufacture, MAC addresses can be spoofed in software — a security nuance N10-009 tests.
PlayPrepHQ study notes are written and reviewed against primary exam sources. How we create & review content →