Spanning-Tree Portfast (Global Configuration) - Cisco Catalyst 3550 Command Reference Manual

spanning-tree portfast (global configuration)

spanning-tree portfast (global configuration)
Use the spanning-tree portfast global configuration command to globally enable bridge protocol data
unit (BPDU) filtering on Port Fast-enabled ports, the BPDU guard feature on Port Fast-enabled ports, or
the Port Fast feature on all nontrunking ports. The BPDU filtering feature prevents the switch port from
sending or receiving BPDUs. The BPDU guard feature puts Port Fast-enabled ports that receive BPDUs
in an error-disabled state. Use the no form of this command to return to the default setting.
Syntax Description bpdufilter default
bpduguard default
default
Defaults
The BPDU filtering, the BPDU guard, and the Port Fast features are disabled on all ports unless they are
individually configured.
Command Modes
Global configuration
Command History Release
12.1(4)EA1
12.1(9)EA1
Usage Guidelines You can enable these features when the switch is operating in the per-VLAN spanning-tree plus
(PVST+), 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 ports that are Port Fast-enabled (the ports are in a Port Fast-operational state). The
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 ports do not receive
BPDUs. If a BPDU is received on a Port Fast-enabled port, the port loses its Port Fast-operational status
and BPDU filtering is disabled.
You can override the spanning-tree portfast bpdufilter default global configuration command by
using the spanning-tree bdpufilter interface configuration command.
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spanning-tree portfast {bpdufilter default | bpduguard default | default}
no spanning-tree portfast {bpdufilter default | bpduguard default | default}
Globally enable BPDU filtering on Port Fast-enabled ports and prevent the
switch port connected to end stations from sending or receiving BPDUs.
Globally enable the BPDU guard feature on Port Fast-enabled ports and place
the ports that receive BPDUs in an error-disabled state.
Globally enable the Port Fast feature on all nontrunking ports. When the Port
Fast feature is enabled, the port changes directly from a blocking state to a
forwarding state without making the intermediate spanning-tree state
changes.
Modification
This command was first introduced.
The bpdufilter default and default keywords were added.
Chapter 2 Cisco IOS Commands
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