3Com 7750 Series - page 220

3Com Switch 7750 Series
Command Reference Guide – Port Security & Port Binding Chapter 1 Port Security Commands
1-8
View
Ethernet port view
Parameter
ntkonly: Allows the port to transmit only unicast packets with
successfully-authenticated destination MAC addresses.
ntk-withbroadcasts: Allows the port to transmit broadcast packets and unicast
packets with successfully-authenticated destination MAC addresses.
ntk-withmulticasts: Allows the port to transmit multicast packets, broadcast packets
and unicast packets with successfully-authenticated destination MAC addresses.
Description
Use the port-security ntk-mode command to set the packet transmission mode the
port adopts when the NTK feature is triggered.
Use the undo port-security ntk-mode command to cancel the setting of packet
transmission mode.
By default, no transmission mode is set on the port.
Table 1-2 shows the trigger conditions of the NTK feature.
 Note:
By checking the destination MAC addresses of the data frames to be sent from a port,
the NTK feature ensures that only successfully authenticated devices can obtain data
frames from the port, thus preventing illegal devices from intercepting network data.
Example
# Enter system view.
<3Com> system-view
System View: return to User View with Ctrl+Z.
# Enable port security.
[3Com] port-security enable
# Enter GigabitEthernet1/0/1 port view.
[3Com] interface GigabitEthernet1/0/1
# Set the packet transmission mode of the NTK feature to ntk-withbroadcasts on the
current port.
[3Com-GigabitEthernet1/0/1] port-security ntk-mode ntk-withbroadcasts