PurposeCommand or Action
Enables the PortFast feature.spanning-tree portfast
Example:
Switch(config-if)# spanning-tree portfast
Step 4
Returns to privileged EXEC mode.end
Example:
Switch(config-if)# end
Step 5
What to Do Next
To prevent the port from shutting down, you can use the errdisable detect cause bpduguard shutdown vlan
global configuration command to shut down just the offending VLAN on the port where the violation occurred.
You also can use the spanning-tree bpduguard enable interface configuration command to enable BPDU
guard on any port without also enabling the PortFast feature. When the port receives a BPDU, it is put it in
the error-disabled state.
Related Topics
BPDU Guard, on page 80
Enabling BPDU Filtering
You can also use the spanning-tree bpdufilter enable interface configuration command to enable BPDU
filtering on any interface without also enabling the PortFast feature. This command prevents the interface
from sending or receiving BPDUs.
Enabling BPDU filtering on an interface is the same as disabling spanning tree on it and can result in
spanning-tree loops.
Caution
You can enable the BPDU filtering feature if your switch is running PVST+, Rapid PVST+, or MSTP.
Configure PortFast 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.
Caution
This procedure is optional.
Beginning in privileged EXEC mode, follow these steps to enable BPDU filtering on the switch.
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
OL-29424-01 93
Configuring Optional Spanning-Tree Features
Enabling BPDU Filtering
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