A mechanism used to control access to a wired or wireless computer network. Before a newly connected computer is allowed to communicate over the network, its hardware address (MAC Address) is checked against a list of known and permitted computers. MAC addresses are used to uniquely identify the network card of a computer. Address verification is not a ­tamper-proof mechanism to prevent connection from unauthorized computers because attackers can “spy out” valid MAC addresses and set their MAC address to spoof an otherwise authorized address, thus gaining access to the network.

See Also: Computer; Message Authentication Code Address (MAC Address); Network; Wireless.