Many devices that support MAC filtering do so on a device basis. Whitelisted MAC addresses are allowed through any
port on the device and blacklisted MAC addresses are blocked on all ports. Other devices, such as Cisco Catalyst switches, support MAC filtering on a port-by-port basis. This is referred to as
port security. Port security may be configured statically with a list, dynamically based on the first given number of addresses detected, or a combination of these two methods. When port security is configured, the default settings are to allow only one MAC address per port, and to shut down the port if the allowed number of addresses is exceeded. ==See also==