3Com Switch 4200G Configuration Guide

136 CHAPTER 20: MSTP CONFIGURATION
Performing the mCheck operation in system view
Performing the mCheck operation in Ethernet port view
CAUTION: The stp mcheck command takes effect only when the switch operate in
MSTP mode, and does not take effect when the switch operates in STP/RSTP mode.)
Configuration Example
1 Perform the mCheck operation on GigabitEthernet1/0/1 port (assuming that the
switch operates in MSTP mode and the port operates in the STP/RSTP mode).
■ Configure in system view.
<S4200G> system-view
System View: return to User View with Ctrl+Z.
[4200G] stp interface GigabitEthernet1/0/1 mcheck
■ Configure in Ethernet port view.
<S4200G> system-view
System View: return to User View with Ctrl+Z.
[4200G] interface GigabitEthernet1/0/1
[4200G-GigabitEthernet1/0/1] stp mcheck
Protection Function
Configuration
Introduction The following protection functions are provided on MSTP-enabled switches: BPDU
protection, root protection, loop prevention, and TC-BPDU attack prevention.
BPDU protection
Normally, the access ports of the devices operating on the access layer directly
connect to terminals (such as PCs) or file servers. These ports are usually configured as
edge ports to achieve rapid transition. But they resume non-edge ports automatically
upon receiving configuration BPDUs, which causes spanning tree regeneration and
network topology jitter.
Normally, no configuration BPDU will reach edge ports. But malicious users can attack
a network by sending configuration BPDUs deliberately to edge ports to cause
network jitter. You can prevent this type of attacks by utilizing the BPDU protection
function. With this function enabled on a switch, the switch shuts down the edge
ports that receive configuration BPDUs and then reports these cases to the
administrator. If a port is shut down, only the administrator can restore it.
Table 109 Perform the mCheck operation in system view
Operation Command Description
Enter system view System-view —
Perform the mCheck
operation
stp [ interface interface-list ]
mcheck
Required
Table 110 Perform the mCheck operation in Ethernet port view
Operation Command Description
Enter system view system-view —
Enter Ethernet port
view
interface interface-type
interface-number
—
Perform the mCheck
operation
stp mcheck Required