CCNA Routing and Switching (legacy) — Question 30

Under which two circumstances is a switch port that is configured with PortFast BPDU guard error-disabled? (Choose two.)

Answer options

• A. when the switch receives a BPDU from a connected switch
• B. when the switch receives a request for an IP address from an individual PC
• C. when a connected server has more than one VLAN configured on its NIC
• D. when a wireless access point running in bridge mode is connected to a switch
• E. when a single IP address is configured on the switch AC

Correct answer:

Explanation

The correct answers are A and D. A switch port with PortFast BPDU guard goes into error-disabled mode when it receives a BPDU from a connected switch (A), indicating a potential loop, or when a wireless access point in bridge mode connects, which could also send BPDUs (D). The other options do not trigger this behavior as they do not involve BPDU transmission.