Which of the following best describes MAC filtering's access control?

• A. It blocks all traffic regardless of device identity.
• B. It restricts network access to devices with allowed MAC addresses.
• C. It encrypts all traffic on the wireless channel.
• D. It monitors user activity for billing.

Answer: (B)

MAC filtering is a simple access control mechanism at the data-link layer that permits only devices with approved MAC addresses to associate with the wireless network. When a device tries to connect, the access point checks its hardware MAC against a configured whitelist; if it matches, access is granted, otherwise it’s denied. This directly describes restricting network access to devices with allowed MAC addresses. It’s not about blocking all traffic, encryption of traffic, or monitoring for billing. In practice, MAC filtering can be bypassed by MAC spoofing, so it’s not a strong security measure by itself and should be used with stronger protections like WPA2/WPA3.