Configuring Port Security - Cisco Catalyst 3550 series Software Configuration Manual

Configuring Port Security

Configuring Port Security
You can use the port security feature to restrict input to an interface by limiting and identifying MAC
addresses of the stations allowed to access the port. When you assign secure MAC addresses to a secure
port, the port does not forward packets with source addresses outside the group of defined addresses.
This section includes information about these topics:
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Understanding Port Security
This section includes information about:
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Secure MAC Addresses
You can configure these types of secure MAC addresses:
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You can configure an interface to convert the dynamic MAC addresses to sticky secure MAC addresses
and to add them to the running configuration by enabling sticky learning. To enable sticky learning, enter
the switchport port-security mac-address sticky interface configuration command. When you enter
this command, the interface converts all the dynamic secure MAC addresses, including those that were
dynamically learned before sticky learning was enabled, to sticky secure MAC addresses.
The sticky secure MAC addresses do not automatically become part of the configuration file, which is
the startup configuration used each time the switch restarts. If you save the sticky secure MAC addresses
in the configuration file, when the switch restarts, the interface does not need to relearn these addresses.
If you do not save the configuration, they are lost.
If sticky learning is disabled, the sticky secure MAC addresses are converted to dynamic secure
addresses and are removed from the running configuration.
The maximum number of available MAC addresses on a secure port or VLAN is determined by the active
Switch Database Management (SDM) template. See the
User-Selected Features" section on page 7-27
Catalyst 3550 Multilayer Switch Software Configuration Guide
21-8
Understanding Port Security, page 21-8
Default Port Security Configuration, page 21-10
Port Security Configuration Guidelines, page 21-10
Enabling and Configuring Port Security, page 21-11
Enabling and Configuring Port Security Aging, page 21-14
Secure MAC Addresses, page 21-8
Security Violations, page 21-9
Static secure MAC addresses—These are manually configured by using the switchport
port-security mac-address mac-address interface configuration command, stored in the address
table, and added to the switch running configuration.
Dynamic secure MAC addresses—These are dynamically learned, stored only in the address table,
and removed when the switch restarts.
Sticky secure MAC addresses—These can be dynamically learned or manually configured, stored in
the address table, and added to the running configuration. If these addresses are saved in the
configuration file, the interface does not need to dynamically relearn them when the switch restarts.
Although sticky secure addresses can be manually configured, we do not recommend it.
Chapter 21 Configuring Port-Based Traffic Control
"Optimizing System Resources for
for more information about configuring an SDM template.
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