Cisco WS-C3560E-48PD-SF Command Reference - Page 629

Chapter 2 Catalyst 3560 Switch Cisco IOS Commands 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 interfaces, the BPDU guard feature on Port Fast-enabled interfaces, or the Port Fast feature on all nontrunking interfaces. The BPDU filtering feature prevents the switch interface from sending or receiving BPDUs. The BPDU guard feature puts Port Fast-enabled interfaces that receive BPDUs in an error-disabled state. Use the no form of this command to return to the default settings. spanning-tree portfast {bpdufilter default | bpduguard default | default} no spanning-tree portfast {bpdufilter default | bpduguard default | default} Syntax Description bpdufilter default bpduguard default default Globally enable BPDU filtering on Port Fast-enabled interfaces and prevent the switch interface connected to end stations from sending or receiving BPDUs. Globally enable the BPDU guard feature on Port Fast-enabled interfaces and place the interfaces that receive BPDUs in an error-disabled state. Globally enable the Port Fast feature on all nontrunking interfaces. When the Port Fast feature is enabled, the interface changes directly from a blocking state to a forwarding state without making the intermediate spanning-tree state changes. Defaults The BPDU filtering, the BPDU guard, and the Port Fast features are disabled on all interfaces unless they are individually configured. Command Modes Global configuration Command History Release 12.1(19)EA1 Modification This command was introduced. 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 interfaces that are Port Fast-enabled (the interfaces are in a Port Fast-operational state). The interfaces 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 interfaces do not receive BPDUs. If a BPDU is received on a Port Fast-enabled interface, 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 by using the spanning-tree bdpufilter interface configuration command. 78-16405-05 Catalyst 3560 Switch Command Reference 2-597