•
Dynamic secure MAC addresses
—
These are dynamically configured, 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, when the switch restarts, the interface does not need to dynamically reconfigure them.
Sticky Secure MAC Addresses
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. 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. All sticky secure MAC addresses are added to the running configuration.
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 sticky secure addresses, 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.
Security Violations
It is a security violation when one of these situations occurs:
•
The maximum number of secure MAC addresses have been added to the address table, and a station
whose MAC address is not in the address table attempts to access the interface.
•
An address learned or configured on one secure interface is seen on another secure interface in the same
VLAN.
You can configure the interface for one of three violation modes, based on the action to be taken if a violation
occurs:
•
protect
—
when the number of secure MAC addresses reaches the maximum limit allowed on the port,
packets with unknown source addresses are dropped until you remove a sufficient number of secure
MAC addresses to drop below the maximum value or increase the number of maximum allowable
addresses. You are not notified that a security violation has occurred.
We do not recommend configuring the protect violation mode on a trunk port. The
protect mode disables learning when any VLAN reaches its maximum limit, even if the
port has not reached its maximum limit.
Note
•
restrict
—
when the number of secure MAC addresses reaches the maximum limit allowed on the port,
packets with unknown source addresses are dropped until you remove a sufficient number of secure
MAC addresses to drop below the maximum value or increase the number of maximum allowable
addresses. In this mode, you are notified that a security violation has occurred. An SNMP trap is sent,
a syslog message is logged, and the violation counter increments.
Catalyst 2960-X Switch Security Configuration Guide, Cisco IOS Release 15.0(2)EX
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Configuring Port-Based Traffic Control
Sticky Secure MAC Addresses