📖 What is BPDU Guard?
A security feature that error-disables a switch port if a BPDU is received on it, preventing unauthorized switches from affecting the STP topology.
🥋
Sensei Says:
"BPDU Guard is typically paired with PortFast. It's a classic exam question: 'How do you protect an edge port from a user plugging in a rogue switch?' Answer: BPDU Guard."
📚 Certification: Certified Network Associate (200-301)
🔑 What are the Key Concepts of BPDU Guard?
- ▸ Protects the STP topology from unauthorized switches
- ▸ Places the port into an 'err-disable' state upon receiving a BPDU
- ▸ Best practice companion feature to PortFast
🎯 How does BPDU Guard appear on the 200-301 Exam?
Securing access ports to prevent a user from inadvertently causing a spanning tree loop by plugging in an unmanaged switch.
Recovering a port that has been error-disabled due to BPDU Guard.
❓ Frequently Asked Questions
What state does a port enter if BPDU Guard triggers?
The port is shut down and placed into the 'err-disable' state.
How do you recover a port from the err-disable state?
You must manually issue a 'shutdown' followed by 'no shutdown' on the interface, or configure errdisable recovery.
Related Terms from Certified Network Associate
Native VLAN
Single-Mode Fiber (SMF)
Northbound API
Broadcast Domain
Access Control List (ACL)
Switchport Mode Dynamic Auto