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Catalyst 2960 and 2960-S Switch Software Configuration Guide
OL-8603-09
Chapter 5 Administering the Switch
Managing the MAC Address Table
• If you disable MAC address learning on a VLAN configured as a private-VLAN primary VLAN,
MAC addresses are still learned on the secondary VLAN that belongs to the private VLAN and are
then replicated on the primary VLAN. If you disable MAC address learning on the secondary
VLAN, but not the primary VLAN of a private VLAN, MAC address learning occurs on the primary
VLAN and is replicated on the secondary VLAN.
• You cannot disable MAC address learning on an RSPAN VLAN. The configuration is not allowed.
• If you disable MAC address learning on a VLAN that includes a secure port, MAC address learning
is not disabled on that port. If you disable port security, the configured MAC address learning state
is enabled.
Beginning in privileged EXEC mode, follow these steps to disable MAC address learning on a VLAN:
To reenable MAC address learning on a VLAN, use the default mac address-table learning vlan
vlan-id global configuration command. You can also reenable MAC address learning on a VLAN by
entering the mac address-table learning vlan vlan-id global configuration command. The first
(default) command returns to a default condition and therefore does not appear in the output from the
show running-config command. The second command causes the configuration to appear in the show
running-config privileged EXEC command display.
This example shows how to disable MAC address learning on VLAN 200:
Switch(config)# no mac address-table learning vlan 200
You can display the MAC address learning status of all VLANs or a specified VLAN by entering the
show mac-address-table learning [vlan vlan-id] privileged EXEC command.
Displaying Address Table Entries
You can display the MAC address table by using one or more of the privileged EXEC commands
described in Table 5-4:
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
no mac address-table learning vlan
vlan-id
Disable MAC address learning on the specified VLAN or VLANs. You
can specify a single VLAN ID or a range of VLAN IDs separated by a
hyphen or comma. Valid VLAN IDs are 1 to 4094.
Step 3
end Return to privileged EXEC mode.
Step 4
show mac address-table learning [vlan
vlan-id]
Verify the configuration.
Step 5
copy running-config startup-config (Optional) Save your entries in the configuration file.
Table 5-4 Commands for Displaying the MAC Address Table
Command Description
show ip igmp snooping groups Displays the Layer 2 multicast entries for all VLANs or the specified VLAN.
show mac address-table address Displays MAC address table information for the specified MAC address.
show mac address-table aging-time Displays the aging time in all VLANs or the specified VLAN.
show mac address-table count Displays the number of addresses present in all VLANs or the specified VLAN.