User's Manual

7-22
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 7 Administering the Switch
Managing the MAC Address Table
Beginning in privileged EXEC mode, follow these steps to configure the dynamic address table aging
time:
To return to the default value, use the no mac addr
ess-table aging-time global configuration command.
Removing Dynamic Address Entries
To remove all dynamic entries, use the clear mac address-table dynamic command in privileged EXEC
mode. You can also remove a specific MAC address (clear mac address-table dynamic address
mac-address), remove all addresses on the specified physical port or port channel (clear mac
address-table dynamic interface interface-id), or remove all addresses on a specified VLAN (clear
mac address-table dynamic vlan vlan-id).
To verify that dynamic entries have been removed, use the sh
ow mac address-table dynamic privileged
EXEC command.
Configuring MAC Address Change Notification Traps
MAC address change notification tracks users on a network by storing the MAC address change activity.
When the switch learns or removes a MAC address, an SNMP notification trap can be sent to the NMS.
If you have many users coming and going from the network, you can set a trap-interval time to bundle
the notification traps to reduce network traffic. The MAC notification history table stores MAC address
activity for each port for which the trap is set. MAC address change notifications are generated for
dynamic and secure MAC addresses. Notifications are not generated for self addresses, multicast
addresses, or other static addresses.
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
mac address-table aging-time [0 |
10-1000000] [vlan vlan-id]
Set the length of time that a dynamic entry remains in the MAC
address table after the entry is used or updated.
The range is 10 to 1000000 seconds. The default is 300. You can also
ent
er 0, which disables aging. Static address entries are never aged
or removed from the table.
For vlan-id, v
alid IDs are 1 to 4094.
Step 3
end Return to privileged EXEC mode.
Step 4
show mac address-table aging-time Verify your entries.
Step 5
copy running-config startup-config (Optional) Save your entries in the configuration file.