CCNA: Cisco Certified Network Associate — Question 1084

How does MAC learning function?

Answer options

• A. sends a retransmission request when a new frame is received
• B. enabled by default on all VLANs and interfaces
• C. populates the ARP table with the egress port
• D. protects against denial of service attacks

Correct answer: B

Explanation

The correct answer is B, as MAC learning is indeed enabled by default on all VLANs and interfaces, allowing switches to learn the MAC addresses of devices. Options A, C, and D are incorrect because they do not accurately describe the function of MAC learning; A refers to frame handling, C relates to ARP, and D pertains to security measures rather than MAC address learning.