Configuring and Monitoring Port Security

Port Security Command Options and Operation

Caution

Note

The address-limitsetting controls how many MAC addresses are allowed in the Authorized Addresses list for a given port. If you remove a MAC address without also reducing the address limit by 1, the port may later detect and accept the same or another MAC address that you do not want in the Authorized Address list. Thus, if you use the CLI to remove a MAC address that is no longer authorized, you should first reduce the Address Limit (address-limit) integer by 1, as shown in the next example. This prevents the possibility of the same device or another device on the network from automatically being accepted as “authorized” for that port. (You can prevent the port from learning unauthorized MAC addresses by using the learn-mode configured option instead of the learn-mode static option. Refer to the Note on page 9-6.)

To remove a device (MAC address) from the “Authorized” list and when the current number of devices equals the Address Limit value, you should first reduce the Address Limit value by 1, then remove the unwanted device.

When you have configured the switch for learn-mode static operation, you can reduce the address limit below the number of currently authorized addresses on a port. This enables you to subsequently remove a device from the “Autho- rized” list without opening the possibility for an unwanted device to automatically become authorized. (If you use learn-mode configured instead, the switch cannot automatically add detected devices not included in the mac- address configuration. Refer to the Note on page 9-6.)

For example, suppose port A1 is configured as shown below and you want to remove 0c0090-123456 from the Authorized Address list:

ProCurve(config)# show port-security 1

 

Port Security

 

Port : 1

 

Learn Mode [Continuous] : Static

Address Limit [1] : 2

Action [None] : None

 

Authorized Addresses

--------------------

0c0090-123456

0c0090-456456

When removing 0c0090-123456, first reduce the Address Limit by 1 to prevent the port from automatically adding another device that it detects on the network.

Figure 9-7. Example of Two Authorized Addresses on Port A1

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