Administrator Guide

bpduguard
(OPTIONAL) Enter the keyword portfast to enable Portfast to move the interface into
Forwarding mode immediately after the root fails.
Enter the keyword bpduguard to disable the port when it receives a BPDU.
shutdown-on-
violation
(OPTIONAL) Enter the keywords shutdown-on-violation to hardware disable an
interface when a BPDU is received and the port is disabled.
priority priority Enter keyword priority then a value in increments of 16 as the priority. The range is
from 0 to 240. The default is 128.
loopguard Enter the keyword loopguard to enable loop guard on an RSTP port or port-channel
interface.
rootguard Enter the keyword rootguard to enable root guard on an RSTP port or port-channel
interface.
Defaults Not configured.
Command Modes INTERFACE
Command History
This guide is platform-specific. For command information about other platforms, refer to the relevant Dell
Networking OS Command Line Reference Guide.
The following is a list of the Dell Networking OS version history for this command.
Version Description
9.9(0.0) Introduced on the C9010.
9.2(1.0) Introduced on the Z9500.
8.3.19.0 Introduced on the S4820T.
8.3.11.1 Introduced on the Z9000.
8.4.2.1 Added support for the optional guard keyword on the C-Series, S-Series, and E-Series
TeraScale.
8.3.7.0 Introduced on the S4810.
8.2.1.0 Introduced the hardware shutdown-on-violation options.
7.6.1.0 Introduced on the S-Series.
7.5.1.0 Introduced on the C-Series.
7.4.1.0 Added the optional bridge port data unit (BPDU) guard.
6.2.1.1 Introduced on the E-Series.
Usage Information
The BPDU guard option prevents the port from participating in an active STP topology in case a BPDU appears
on a port unintentionally, or is misconfigured, or is subject to a DOS attack. This option places the port into an
Error Disable state if a BPDU appears and a message is logged so that the administrator can take corrective
action.
NOTE: A port configured as an edge port, on an RSTP switch, immediately transitions to the
Forwarding state. Only configure ports connected to end-hosts as edge ports. Consider an edge
port similar to a port with a spanning-tree portfast enabled.
If you do not enable shutdown-on-violation, BPDUs are still sent to the RPM CPU.
You cannot enable STP root guard and loop guard at the same time on a port. For example, if you configure loop
guard on a port on which root guard is already configured, the following error message displays: % Error:
RootGuard is configured. Cannot configure LoopGuard.
Enabling Portfast BPDU guard and loop guard at the same time on a port results in a port that remains in a
Blocking state and prevents traffic from flowing through it. For example, when Portfast BPDU guard and loop
guard are both configured:
1406 Rapid Spanning Tree Protocol (RSTP)