What is the purpose of MAC filtering in network security?

MAC filtering plays a vital role in network security by allowing network administrators to control access to the network based on the unique Media Access Control (MAC) addresses of devices. Each network interface card (NIC) has a unique MAC address assigned to it, serving as a hardware identifier. By implementing MAC filtering, administrators can create a whitelist of allowed MAC addresses, ensuring that only devices with these specific addresses can connect to the network.

This offers a layer of security, as unauthorized devices cannot gain access just by knowing the SSID or other typical access credentials. While it is not foolproof and can be bypassed through techniques such as MAC spoofing, it adds a measure of control and deterrence in network environments.

Other options such as improving network performance, encrypting data, or blocking external access focus on different aspects of network functionality and security rather than direct access control through device identification. For instance, enhancing performance might involve optimizing routing protocols or bandwidth allocation, while encryption concerns the confidentiality of data rather than access permissions. Blocking all external access represents a more aggressive approach, typically associated with firewalls rather than filtering based on device identifiers. Thus, the primary purpose of MAC filtering is to provide access control through unique device identification.