CCNA Routing and Switching (legacy) — Question 135

When an interface is configured with PortFast BPDU guard, how does the interface respond when it receives a BPDU?

Answer options

• A. It continues operating normally.
• B. It goes into a down/down state.
• C. It becomes the root bridge for the configured VLAN.
• D. It goes into an errdisable state.

Correct answer: D

Explanation

When an interface with PortFast BPDU guard receives a BPDU, it is designed to protect the network by transitioning into an errdisable state, thus preventing potential loops. The other options are incorrect because the interface cannot continue to operate normally, cannot go down without a specific command, and cannot become the root bridge as it is designed to block BPDUs.