DELL N3000 User Manual

Configuring Port and System Security

The Port Security feature allows you to limit the number of source MAC 

addresses that can be learned on a port. If a port reaches the configured limit, 

any other addresses beyond that limit are not learned and the frames are 

discarded. Frames with a source MAC address that has already been learned 

will be forwarded. 
The purpose of this feature, which is also known as port-MAC locking, is to 

help secure the network by preventing unknown devices from forwarding 

packets into the network. For example, to ensure that only a single device can 

be active on a port, you can set the number of allowable dynamic addresses to 

one. After the MAC address of the first device is learned, no other devices will 

be allowed to forward frames into the network.
When link goes down on a port, all of the dynamically locked addresses are 

cleared from the source MAC address table the feature maintains. When the 

link is restored, that port can once again learn addresses up to the specified 

limit.
The port can learn MAC addresses dynamically, and you can manually specify 

a list of static MAC addresses for a port.

Table 19-2 lists the default values for the Port Security feature.

This section provides information about the OpenManage Switch 

Administrator pages for configuring and monitoring the IEEE 802.1X 

features and Port Security on a Dell Networking N2000, N3000, and N4000 

series switches. For details about the fields on a page, click 

at the top of 

the page.

Port security

Unlocked

Port security traps

Disabled

Maximum learned MAC addresses

100 (when locked)

Monitor mode

Disabled