CompTIA Network+ (N10-007) — Question 239

Which of the following would block access to an untagged port when connected to a Layer 2 device?

Answer options

• A. BPDU guard
• B. Spanning tree
• C. Flood guard
• D. Root guard

Correct answer: B

Explanation

The Spanning Tree Protocol (STP) is designed to prevent loops in a network and can block access to untagged ports by placing them in a blocking state if necessary. BPDU guard, Flood guard, and Root guard serve different purposes; BPDU guard protects against incorrect configurations, Flood guard mitigates traffic flooding, and Root guard prevents a port from becoming a root port, but none specifically block untagged ports.