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200-301 · Question #1502
200-301 Question #1502: Real Exam Question with Answer & Explanation
The correct answer is B: enabled by default on all VLANs and interfaces. MAC address learning is a fundamental function of Layer 2 switches that is enabled by default on all active interfaces within a VLAN.
Submitted by rachelw· Mar 5, 2026Network Access
Question
How does MAC learning function?
Options
- Aoverwrites the known source MAC address in the address table
- Benabled by default on all VLANs and interfaces
- Cprotects against denial of service attacks
- Dforwards frames to a neighbor port using CDP
Explanation
MAC address learning is a fundamental function of Layer 2 switches that is enabled by default on all active interfaces within a VLAN.
Common mistakes.
- A. A switch only overwrites a known MAC address in its table if that MAC address is subsequently learned on a different port, indicating the device has moved, not simply if it's known.
- C. While some MAC-related features like port security contribute to network security, MAC learning itself is primarily a forwarding mechanism and does not directly protect against denial-of-service attacks.
- D. CDP (Cisco Discovery Protocol) is a Layer 2 protocol for discovering directly connected Cisco devices, and it is unrelated to how a switch forwards data frames based on MAC addresses.
Concept tested. Switch MAC address learning mechanism
Topics
#MAC learning#Layer 2 switching
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