3Com 4200G 12-Port Configuration Manual page 417

To reduce the risk of being attacked by malicious users against opened socket and enhance switch
security, the Switch 4200G series Ethernet switches provide the following functions, so that a cluster
socket is opened only when it is needed:
Opening UDP port 40000 (used for cluster) only when the cluster function is implemented,
Closing UDP port 40000 at the same time when the cluster function is closed.
On member devices, the preceding functions are implemented as follows:
When you execute the add-member command on the management device to add a candidate
device to a cluster, the candidate device changes to a member device and its UDP port 40000 is
opened at the same time.
When you execute the auto-build command on the management device to have the system
automatically add candidate devices to a cluster, the candidate devices change to member devices
and their UDP port 40000 is opened at the same time.
When you execute the administrator-address command on a device, the device's UDP port
40000 is opened at the same time.
When you execute the delete-member command on the management device to remove a
member device from a cluster, the member device's UDP port 40000 is closed at the same time.
When you execute the undo build command on the management device to remove a cluster, UDP
port 40000 of all the member devices in the cluster is closed at the same time.
When you execute the undo administrator-address command on a member device, UDP port
40000 of the member device is closed at the same time.
Enabling NDP globally and on specific ports
Table 2-13 Enable NDP globally and on specific ports
Operation
Enter system view
Enable NDP globally
In system view
Enable
NDP on
In
specified
Ethernet
ports
port view
Enabling NTDP globally and on a specific port
Table 2-14 Enable NTDP globally and a specific port
Operation
Enter system view
system-view
ndp enable
ndp enable interface port-list
Enter
interface interface-type
Ethernet
interface-number
port view
Enable
NDP on ndp enable
the port
Command
system-view
2-14
Command
—
Description
—
Required
Required
Use either
approach.
Description