R3721-F3210-F3171-HP High-End Firewalls Network Management Configuration Guide-6PW101

101
The spanning tree protocol provides the BPDU guard function to protect the system against such attacks.
With the BPDU guard function enabled on the devices, when edge ports receive configuration BPDUs,
the system will close these ports and notify the NMS that these ports have been closed by the spanning
tree protocol. Ports disabled in this way will be re-activated by the device after a detection interval. For
more information about this detection interval, see Getting Started Guide.
Configure BPDU guard on a device with edge ports configured.
To enable BPDU guard:
Ste
p
Command Remarks
1. Enter system view.
system-view N/A
2. Enable the BPDU guard
function for the device.
stp bpdu-protection Disabled by default.
NOTE:
BPDU guard does not take effect on loopback-testing-enabled ports. For more information about
loopback testing, see the chapter “Interface Configuration.”
Enabling root guard
The root bridge and secondary root bridge of a spanning tree should be located in the same MST region.
Especially for the CIST, the root bridge and secondary root bridge are put in a high-bandwidth core
region during network design. However, due to possible configuration errors or malicious attacks in the
network, the legal root bridge may receive a configuration BPDU with a higher priority. The current legal
root bridge will be superseded by another device, causing an undesired change of the network topology.
As a result, the traffic that should go over high-speed links is switched to low-speed links, resulting in
network congestion.
To prevent this situation, MSTP provides the root guard function. If the root guard function is enabled on
a port of a root bridge, this port plays the role of designated port on all MSTIs. Once this port receives
a configuration BPDU with a higher priority from an MSTI, it immediately sets that port to the listening
state in the MSTI, without forwarding the packet (this is equivalent to disconnecting the link connected
with this port in the MSTI). If the port receives no BPDUs with a higher priority within twice the forwarding
delay, it will revert to its original state.
Configure root guard on a designated port.
To enable root guard:
Ste
p
Command Remarks
1. Enter system view.
system-view N/A
2. Enter Ethernet interface view or Layer 2
aggregate interface view.
interface interface-type
interface-number
N/A
3. Enable the root guard function for the
ports.
stp root-protection Disabled by default.
NOTE:
A
mon
g
loop
g
uard, root
g
uard and ed
g
e port settin
g
s, only one function (whichever is configured the
earliest) can take effect on a port at the same time.