Reference Guide

Layer 2 | 547
Display the MAC Address Table
To display the contents of the MAC address table:
MAC Learning Limit
This section has the following sub-sections:
• mac learning-limit dynamic
• mac learning-limit station-move
• mac learning-limit no-station-move
• Displaying MAC Learning-Limited Interfaces
• Learning Limit Violation Actions
• Station Move Violation Actions
• Recovering from Learning Limit and Station Move Violations
• Per-VLAN MAC Learning Limit
MAC Address Learning Limit is a method of port security on Layer 2 physical, port-channel, and VLAN
interfaces. It enables you to set an upper limit on the number of MAC addresses learned on an interface/
VLAN. After the limit is reached, the system drops all traffic from a device with an unlearned MAC
address.
Task Command Syntax Command Mode
Display the contents of the MAC address table.
• address displays the specified entry.
• aging-time displays the configured aging-time.
• count displays the number of dynamic and static entries for all
VLANs, and the total number of entries.
• dynamic displays only dynamic entries
• interface displays only entries for the specified interface.
• static displays only static entries.
• vlan displays only entries for the specified VLAN.
show mac-address-table
[address | aging-time [vlan
vlan-id]| count | dynamic |
interface | static | vlan]
EXEC Privilege
FTOS Behavior: When configuring MAC Learning Limit on a port or VLAN the configuration is
accepted (becomes part of running-config and show mac learning-limit interface) before the system
verifies that sufficient CAM space exists. If the CAM check fails, the a message is displayed:
%E90MH:5 %ACL_AGENT-2-ACL_AGENT_LIST_ERROR: Unable to apply access-list
Mac-Limit on GigabitEthernet 5/84
In this case, the configuration is still present in the running-config and show output. Remove the configuration
before re-applying a MAC learning limit with lower value. Also, ensure that Syslog messages can be viewed on
your session.
Note: The CAM-check failure message beginning in FTOS version 8.3.1.0 is different from versions
8.2.1.1 and earlier, which read:
% Error: ACL returned error
% Error: Remove existing limit configuration if it was configured before