Enabling Bpdu Guard On A Specified Interface - Cisco Catalyst 4500 Series Software Configuration Manual

About PortFast Edge BPDU Filtering
Extended system ID
PortFast Edge BPDU Guard Default
Portfast Edge BPDU Filter Default
Portfast Default
Bridge Assurance
Loopguard
UplinkFast
BackboneFast
Pathcost method used is short
Name
---------------------- -------- --------- -------- ---------- ----------
2 vlans

Enabling BPDU Guard on a Specified Interface

Command
Step 1
Switch# configure terminal
Step 2
Switch(config)# interface {{fastethernet |
gigabitethernet | tengigabitethernet} slot/port} |
{port-channel port_channel_number}
Step 3
Switch(config-if)# spanning-tree portfast edge
bpduguard default
Step 4
Switch(config)# end
Step 5
Switch# show spanning-tree summary
About PortFast Edge BPDU Filtering
Cisco IOS Release 12.2(31)SGA and later support PortFast edge BPDU filtering, which allows the
administrator to prevent the system from sending or even receiving BPDUs on specified ports.
When configured globally, PortFast edge BPDU filtering applies to all operational PortFast edge ports.
Ports in an operational PortFast edge state are supposed to be connected to hosts that typically drop
BPDUs. If an operational PortFast edge port receives a BPDU, it immediately loses its operational
PortFast edge status. In that case, PortFast edge BPDU filtering is disabled on this port and STP resumes
sending BPDUs on this port.
PortFast edge BPDU filtering can also be configured on a per-port basis. When PortFast edge BPDU
filtering is explicitly configured on a port, it does not send any BPDUs and drops all BPDUs it receives.
Caution Explicitly configuring PortFast edge BPDU filtering on a port that is not connected to a host can result
in bridging loops, because the port ignores any BPDU it receives and goes to the forwarding state.
When you enable PortFast edge BPDU filtering globally and set this port configuration as the default for
PortFast edge BPDU filtering (see the
enables or disables PortFast edge BPDU filtering.
Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
26-16
is enabled
is enabled
is disabled
is edge
is enabled
is disabled
is disabled
is disabled
Blocking Listening Learning Forwarding STP Active
0 0 0
Purpose
Enters global configuration mode.
Specifies an interface to configure.
Enables BPDU Guard on the specified edge port.
Use the no keyword to disable BPDU guard.
Exits configuration mode.
Verifies the BPDU configuration.
"Enabling BackboneFast" section on page
Chapter 26 Configuring Optional STP Features
3 3
26-23), PortFast