What Does BPDU Guard Mean in 200-301?
Quick Definition
Shuts down a PortFast-enabled port if it receives a BPDU, protecting the spanning tree.
Full Definition
BPDU Guard protects access ports configured with PortFast. If a port with BPDU Guard receives a BPDU (from a rogue switch or misconfigured device), BPDU Guard immediately puts the port into an errdisabled state and shuts it down. This prevents a rogue switch from affecting the spanning tree topology. An errdisabled port must be manually recovered with 'shutdown' followed by 'no shutdown', or auto-recovery can be configured.
CLI Command
interface GigabitEthernet0/1 spanning-tree bpduguard enable spanning-tree portfast bpduguard default ! global
Exam Trap — Don't Get Fooled
BPDU Guard puts the port in errdisabled state, not just blocking. An errdisabled port shows 'err-disabled' in the interface status and must be manually or automatically re-enabled.
Related 200-301 Terms
A Layer 2 loop-prevention protocol that blocks redundant paths in a switched network.
The STP control frames that switches exchange to elect the Root Bridge and maintain the spanning tree.
An STP feature that bypasses the Listening and Learning states on access ports, putting them immediately into Forwarding.
Prevents a port from becoming the Root Port, protecting the Root Bridge position.
Frequently Asked Questions
What does BPDU Guard mean on the 200-301 exam?
BPDU Guard protects access ports configured with PortFast. If a port with BPDU Guard receives a BPDU (from a rogue switch or misconfigured device), BPDU Guard immediately puts the port into an errdisabled state and shuts it down. This prevents a rogue switch from affecting the spanning tree topology. An errdisabled port must be manually recovered with 'shutdown' followed by 'no shutdown', or auto-recovery can be configured.
How does BPDU Guard appear as a trap on the 200-301?
BPDU Guard puts the port in errdisabled state, not just blocking. An errdisabled port shows 'err-disabled' in the interface status and must be manually or automatically re-enabled.
How important is BPDU Guard on the 200-301 exam?
BPDU Guard falls under the Spanning Tree domain of the 200-301 exam. Understanding it in context with related terms like stp and portfast is essential for answering scenario-based questions correctly.