MAC filtering

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In computer networking, MAC Filtering (or EUI filtering, or layer 2 address filtering) refers to a security access control methodology whereby the 48-bit address assigned to each network card is used to determine access to the network.

MAC addresses are uniquely assigned to each card, so using MAC filtering on a network permits and denies network access to specific devices through the use of blacklists and whitelists. While the restriction of network access through the use of lists is straightforward, an individual person is not identified by a MAC address, rather a device only, so an authorized person will need to have a whitelist entry for each device that he or she would use to access the network.

In theory, MAC filtering allows a network administrator to permit or deny network access to hosts associated with the MAC address, though in practice there are methods to circumvent this form of access control through address modification ("spoofing") or the physical exchange of network cards between hosts.