Cisco Catalyst 3550

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Catalyst 3550 Multilayer Switch Command Reference
OL-8566-01
Chapter 2 Catalyst 3550 Switch Cisco IOS Commands
spanning-tree bpduguard
spanning-tree bpduguard
Use the spanning-tree bpduguard interface configuration command to put a port in the error-disabled
state when it receives a bridge protocol data unit (BPDU). Use the no form of this command to return to
the default setting.
spanning-tree bpduguard {disable | enable}
no spanning-tree bpduguard
Syntax Description
Defaults BPDU guard is disabled.
Command Modes Interface configuration
Command History
Usage Guidelines The BPDU guard feature provides a secure response to invalid configurations because you must
manually put the port back in service. Use the BPDU guard feature in a service-provider network to
prevent a port from being included in the spanning-tree topology.
You can enable the BPDU guard feature when the switch is operating in the per-VLAN spanning-tree
plus (PVST+), rapid-PVST+, or the multiple spanning-tree (MST) mode.
You can globally enable BPDU guard on all Port Fast-enabled ports by using the spanning-tree portfast
bpduguard default global configuration command.
You can use the spanning-tree bpduguard interface configuration command to override the setting of
the spanning-tree portfast bpduguard default global configuration command.
Examples This example shows how to enable the BPDU guard feature on a port:
Switch(config)# interface fastethernet0/1
Switch(config-if)# spanning-tree bpduguard enable
You can verify your setting by entering the show running-config privileged EXEC command.
disable Disable BPDU guard on the specified interface.
enable Enable BPDU guard on the specified interface.
Release Modification
12.1(9)EA1 This command was introduced.