Configuration Guide     146
Managing MAC Address Table Security Configurations
Step 2 mac address-table security vid 
vid
 max-learn 
num
 {drop | forward | disable}
Configure the maximum number of MAC addresses in the specified VLAN and select a mode 
for the switch to adopt when the maximum number is exceeded.
vid
: Specify an existing VLAN in which you want to limit the number of MAC addresses.
num
: Set the maximum number of MAC addresses in the specific VLAN. It ranges from 0 to 
16383.
drop | forward | disable: The mode that the switch adopts when the maximum number of MAC 
addresses in the specified VLAN is exceeded. 
drop: Packets of new source MAC addresses in the VLAN will be dropped when the maximum 
number of MAC addresses in the specified VLAN is exceeded. 
forward: Packets of new source MAC addresses will be forwarded but the addresses not 
learned when the maximum number of MAC addresses in the specified VLAN is exceeded. 
disable: The number limit on the VLAN is not valid, and the switch follows the original forwarding 
rules.
Step 3 end
Return to privileged EXEC mode. 
Step 4 copy running-config startup-config
Save the settings in the configuration file.
The following example shows how to limit the number of MAC addresses to 100 in VLAN 
10, and configure the switch to drop packets of new source MAC addresses when the limit 
is exceeded.
Switch#configure
Switch(config)#mac address-table security vid 10 max-learn 100 drop
Switch(config)#show mac address-table security vid 10
VlanId          Max-learn       Current-learn   Status
------             ---------           -------------         ------
10                 100                        0                          Drop
Switch(config)#end
Switch#copy running-config startup-config