What kind of control is MAC address filtering on a router?

MAC address filtering on a router is classified as a technical control because it involves the use of technology to restrict access to a network based on the Media Access Control (MAC) addresses of devices. This method allows network administrators to specify which devices can connect to the network by allowing or denying traffic associated with certain MAC addresses.

By implementing MAC address filtering, routers can enforce network access policies at the data link layer of the OSI model, making this control a direct application of technical means to secure a network environment. This differs from physical controls, which involve physical barriers to access, and administrative controls, which relate to policies and procedures governing behavior and access rights. Therefore, technical controls like MAC address filtering are crucial for network security management, as they offer an automated means to enforce access policies without requiring constant human oversight.