Implementing Cisco IP Switched Networks (CCNP SWITCH, legacy) — Question 175

What is the effect of configuring the following command on a switch?
Switch(config) # spanning-tree portfast bpdufilter default

Answer options

• A. If BPDUs are received by a port configured for PortFast, then PortFast is disabled and the BPDUs are processed normally.
• B. If BPDUs are received by a port configured for PortFast, they are ignored and none are sent.
• C. If BPDUs are received by a port configured for PortFast, the port transitions to the forwarding state.
• D. The command enables BPDU filtering on all ports regardless of whether they are configured for BPDU filtering at the interface level.

Correct answer: A

Explanation

The correct answer is A because the command allows BPDUs to be processed normally if they are received on a PortFast-enabled port, which disables PortFast. Options B and C are incorrect as they misinterpret the command's behavior regarding BPDU handling. Option D is also incorrect since the command specifically applies BPDU filtering settings at the default level, not universally to all ports.