Enabling Root Guard - Cisco Catalyst 2960 series Configuration Manual

How to Configure Optional Spanning-Tree Features

Enabling Root Guard

Root guard enabled on an interface applies to all the VLANs to which the interface belongs. Do not enable
the root guard on interfaces to be used by the UplinkFast feature. With UplinkFast, the backup interfaces (in
the blocked state) replace the root port in the case of a failure. However, if root guard is also enabled, all the
backup interfaces used by the UplinkFast feature are placed in the root-inconsistent state (blocked) and are
prevented from reaching the forwarding state.
Note You cannot enable both root guard and loop guard at the same time.
You can enable this feature if your switch is running PVST+, Rapid PVST+, or MSTP.
This procedure is optional.
Follow these steps to enable root guard on the switch.
SUMMARY STEPS
1. enable
2. configure terminal
3. interface interface-id
4. spanning-tree guard root
5. end
DETAILED STEPS
Command or Action
Step 1
enable
Example:
Switch> enable
Step 2 configure terminal
Example:
Switch# configure terminal
Step 3
interface interface-id
Example:
Switch(config)# interface gigabitethernet1/0/2
Step 4
spanning-tree guard root
Consolidated Platform Configuration Guide, Cisco IOS Release 15.2(4)E (Catalyst 2960-X Switches)
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Purpose
Enables privileged EXEC mode. Enter your password if
prompted.
Enters the global configuration mode.
Specifies an interface to configure, and enters interface
configuration mode.
Enables root guard on the interface.