BPDU Guard
BPDU Guard disables an edge/PortFast port if it receives a BPDU, preventing loops.
Updated: 2026-03-05
Definition
BPDU Guard is a safety feature: if a PortFast/edge port receives a BPDU, it is shut down (err-disabled).
It prevents accidentally connecting a switch into an access port and creating a loop.
Key points
- Protects edge ports from loops
- Works with PortFast
- Triggers err-disable on BPDU receive
Common mistakes
- Not using it on access ports in user areas.
- Enabling PortFast without guard features.
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