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Cisco ME 3800X and 3600X Switch Software Configuration Guide
OL-23400-01
Chapter 15 Configuring Optional Spanning-Tree Features
Configuring Optional Spanning-Tree Features
You can also use the spanning-tree bpdufilter enable interface configuration command to enable
BPDU filtering on any STP port without also enabling the Port Fast feature. This command prevents the
STP port from sending or receiving BPDUs.
Caution
Enabling BPDU filtering on an STP port is the same as disabling spanning tree on it and can result in
spanning-tree loops.
You can enable the BPDU filtering feature if your switch is running PVST+, rapid PVST+, or MSTP.
Beginning in privileged EXEC mode, follow these steps to globally enable the BPDU filtering feature.
This procedure is optional.
To disable BPDU filtering, use the no spanning-tree portfast bpdufilter default global configuration
command.
You can override the setting of the no spanning-tree portfast bpdufilter default global configuration
command by using the spanning-tree bpdufilter enable interface configuration command on an STP
port.
Enabling EtherChannel Guard
You can enable EtherChannel guard to detect an EtherChannel misconfiguration if your switch is
running PVST+, rapid PVST+, or MSTP.
Beginning in privileged EXEC mode, follow these steps to enable EtherChannel guard. This procedure
is optional.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
spanning-tree portfast bpdufilter default
Globally enable BPDU filtering. (By default, BPDU filtering is
disabled.)
Note
Globally enabling BPDU filtering enables it only on STP
ports; the command has no effect on UNIs or ENIs on
which STP is not enabled.
Step 3
interface interface-id
Specify the interface connected to an end station, and enter
interface configuration mode.
Step 4
spanning-tree portfast
Enable the Port Fast feature.
Step 5
end
Return to privileged EXEC mode.
Step 6
show running-config
Verify your entries.
Step 7
copy running-config startup-config
(Optional) Save your entries in the configuration file.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
spanning-tree etherchannel guard misconfig
Enable EtherChannel guard.
Step 3
end
Return to privileged EXEC mode.