Which of the following is an example of a firewall allow rule for a MAC address?

• A. add allow IP 192.168.1.1 any in
• B. add deny MAC 00:d0:59:aa:af:80 any in
• C. add allow MAC 00:d0:59:aa:af:80 any in
• D. add allow MAC 11:22:33:44:55:66 any in

Answer: (C)

Filtering by MAC addresses lets a firewall control access for specific devices on the local network. A valid MAC-based allow rule must specify the action (allow), include the MAC address to match, and define the direction (incoming traffic). The example that uses add allow MAC 00:d0:59:aa:af:80 any in does exactly that: it permits traffic from the device with MAC 00:d0:59:aa:af:80 to any destination as it comes into the network. The other options don’t fit because they either refer to an IP address instead of a MAC, specify a deny action, or use a different MAC address.