Cisco Systems WSC4500X16SFP Manual De Usuario

Spanning Tree BPDU guard shuts down PortFast-configured interfaces that receive BPDUs, rather than 
putting them into the spanning tree blocking state. In a valid configuration, PortFast-configured 
interfaces do not receive BPDUs. Reception of a BPDU by a PortFast-configured interface signals an 
invalid configuration, such as connection of an unauthorized device. BPDU guard provides a secure 
response to invalid configurations, because the administrator must manually put the interface back in 
service.

When the BPDU guard feature is enabled, spanning tree applies the BPDU guard feature to all 
PortFast-configured interfaces.

To enable BPDU guard to shut down PortFast-configured interfaces that receive BPDUs, perform this 
task:

This example shows how to enable BPDU guard:

Switch(config)# spanning-tree portfast bpduguard 

Switch(config)# end 

Switch#

This example shows how to verify the BPDU configuration:

Switch# show spanning-tree summary totals

Root bridge for: none.

PortFast BPDU Guard is enabled

Etherchannel misconfiguration guard is enabled

UplinkFast is disabled

BackboneFast is disabled

Default pathcost method used is short

Name                 Blocking Listening Learning Forwarding STP Active

-------------------- -------- --------- -------- ---------- ----------

            34 VLANs 0        0         0        36         36

Switch#

Switch(config)# [no] spanning-tree portfast 

 

Enables BPDU guard on all the switch’s 
PortFast-configured interfaces. 

You can use the no keyword to disable BPDU guard.

Switch(config)# end 

Exits configuration mode. 

Switch# show spanning-tree summary totals

Verifies the BPDU configuration.