Implementing Cisco Network Security (IINS, legacy) — Question 4

If a switch port goes directly into a blocked state only when a superior BPDU is received, what mechanism must be in use?

Answer options

• A. STP BPDU guard
• B. loop guard
• C. STP Root guard
• D. EtherChannel guard

Correct answer: A

Explanation

The correct answer is A, as STP BPDU guard is designed to protect against superior BPDUs, causing the port to enter a blocked state. The other options, such as loop guard and STP Root guard, serve different purposes related to preventing loops and protecting the root bridge, respectively, and do not specifically block a port due to superior BPDUs.