MAC address
also: hardware address, physical address, ethernet address, Layer 2 address
A MAC address (Media Access Control address) is a unique 48-bit identifier assigned to a network interface card (NIC) that identifies devices on a local network. It is used for communication within the same physical network segment.
A MAC address is a hardware address burned into or assigned to every network interface on a local area network (LAN). Written in hexadecimal notation as six pairs of digits separated by colons (for example, 00:1A:2B:3C:4D:5E), it operates at Layer 2 (the data link layer) of the OSI model.
While IP addresses route packets across the internet, MAC addresses handle delivery within a local network segment. When your computer needs to communicate with another device on the same network, it uses ARP (Address Resolution Protocol) to discover the MAC address associated with a target IP address, then sends frames directly to that MAC address.
In Linux, you can view your MAC addresses using commands like ip link show or ifconfig. MAC addresses can also be manually configured (spoofed) for testing or security purposes, allowing a network interface to use a non-standard identifier.