What feature identifies and limits the MAC addresses of the machines that can access the port, forwarding only the packets with source addresses inside the allowed set?

• A. Port security
• B. CAM table
• C. macof
• D. Lawful interception

Answer: (A)

Port security on a switch port is the feature that identifies and limits which MAC addresses can use that port, forwarding only frames whose source MAC addresses are in the allowed set. It works by maintaining an allowlist of MACs (statically configured or learned and stored as sticky entries). When a frame arrives from a source MAC not on the list, the switch drops it and may trigger a security action such as logging, rate limiting, or shutting the port, depending on the violation mode. This mechanism helps prevent unauthorized devices from accessing the network through that port and mitigates MAC address flooding. The CAM table, on the other hand, is the switch's mapping of MAC addresses to switch ports used for forwarding decisions. macof is a tool used to perform a MAC flooding attack to exhaust CAM table resources. Lawful interception refers to authorized monitoring, not access control.