Reference Guide

Layer 2 | 385
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
• 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 port-channel and physical interfaces,
and VLANs. It enables you to set an upper limit on the number of MAC addresses that 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, 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