Specifications

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Catalyst 2950 and Catalyst 2955 Switch Command Reference
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Chapter 2 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
(PVST) or the multiple spanning-tree (MST) mode. The MST mode is available only if you have the
enhanced software image (EI) installed on your switch.
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 first introduced.