CompTIA Network+ Practice Test

What is the effect of MAC flooding on a switch?

1. The switch prioritizes traffic to known MAC addresses

2. The switch becomes inoperable and loses connectivity

3. The switch floods traffic to all interfaces, acting like a hub

4. The switch increases its security protocols

The correct answer is: The switch floods traffic to all interfaces, acting like a hub

When a switch experiences MAC flooding, it overwhelms the switch's MAC address table by sending a large number of frames with different source MAC addresses. As a result, the switch is unable to keep track of which MAC addresses correspond to which ports. When the MAC address table becomes full, the switch cannot learn new MAC addresses. In this state, if a frame arrives with a destination MAC address that is not in the switch's table, the switch treats it as an unknown unicast. Consequently, it floods the frame out of all ports except the one it was received on, effectively behaving like a hub. This is because the switch's function of intelligently directing traffic based on the MAC address table is compromised, leading to increased traffic on the network and possible security vulnerabilities. This behavior highlights the critical role of MAC address management in maintaining efficient switching operations and the potential risks associated with MAC flooding attacks.