Configuring Bpdu Guard - Cisco WS-C2955T-12 Software Manual

Chapter 6 Configuring the System

Configuring BPDU Guard

This feature is not available on the Catalyst 2900 LRE XL switches.
Note
In a valid configuration, Port Fast-enabled interfaces do not receive BPDUs. When the BPDU guard
feature is enabled on the switch, STP shuts down Port Fast-enabled interfaces that receive BPDUs rather
than putting the interfaces into the blocking state.
When enabled on the switch, STP applies the BPDU guard feature to all Port Fast-enabled interfaces.
Note
Caution The BPDU guard feature works on Port Fast-enabled interfaces. Configure Port Fast only on interfaces
that connect to end stations; otherwise, an accidental topology loop could cause a data packet loop and
disrupt switch and network operation.
Beginning in privileged EXEC mode, follow these steps to enable the BPDU guard feature on the switch:
Command
Step 1 configure terminal
Step 2 spanning-tree portfast bpduguard
Step 3
end
Step 4
show spanning-tree summary total
Step 5 copy running-config startup-config
Use the no spanning-tree portfast bpduguard global configuration command to disable BPDU guard.
78-6511-08
Purpose
Enter global configuration mode.
Enable BPDU guard on the switch.
By default, BPDU guard is disabled on the switch.
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide
Configuring STP
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