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Cisco ME 3800X and ME 3600X Switch Command Reference
OL-28238-01
Chapter
spanning-tree portfast (global configuration)
spanning-tree portfast (global configuration)
To globally enable bridge protocol data unit (BPDU) filtering on Port Fast-enabled interfaces, the BPDU
guard feature on Port Fast-enabled STP ports, or the Port Fast feature on all nontrunking STP ports., use
the spanning-tree portfast command in global configuration mode. The BPDU filtering feature
prevents the switch STP port from sending or receiving BPDUs. The BPDU guard feature puts Port
Fast-enabled STP ports that receive BPDUs in an error-disabled state. To return to the default settings,
use the no form of this command.
spanning-tree portfast {bpdufilter default | bpduguard default | default}
no spanning-tree portfast {bpdufilter default | bpduguard default | default}
Syntax Description
Defaults The BPDU filtering, the BPDU guard, and the Port Fast features are disabled on all NNIs or ENIs unless
they are individually configured.
Command Modes Global configuration
Command History
Usage Guidelines You can enable these features when the switch is operating in the per-VLAN spanning-tree plus
(PVST+), the rapid-PVST+, or the multiple spanning-tree (MST) mode.
Use the spanning-tree portfast bpdufilter default global configuration command to globally enable
BPDU filtering on STP ports that are Port Fast-enabled. The STP ports still send a few BPDUs at link-up
before the switch begins to filter outbound BPDUs. You should globally enable BPDU filtering on a
switch so that hosts connected to switch STP ports do not receive BPDUs. If a BPDU is received on a
Port Fast-enabled STP port, the interface loses its Port Fast-operational status and BPDU filtering is
disabled.
You can override the spanning-tree portfast bpdufilter default global configuration command on an
STP port by using the spanning-tree bdpufilter interface configuration command.
bpdufilter default Globally enables BPDU filtering on Port Fast-enabled STP ports, and prevent
the switch STP port connected to end stations from sending or receiving
BPDUs.
bpduguard default Globally enables the BPDU guard feature on Port Fast-enabled STP ports, and
place the STP ports that receive BPDUs in an error-disabled state.
default Globally enables the Port Fast feature on all nontrunking STP ports. When the
Port Fast feature is enabled, the STP port changes directly from a blocking
state to a forwarding state without making the intermediate spanning-tree
state changes.
Release Modification
12.2(52)EY This command was introduced.
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