This command specifies the number of dynamically learned MAC entries allowed for these ports in this VLAN. The range is 0 to 500,000 addresses.
When the learned limit is reached, all new source MAC addresses are blackholed at the ingress and egress points. This prevents these MAC addresses from learning and responding to ICMP and ARP packets.
Dynamically learned entries still get aged and can be cleared. If entries are cleared or aged out after the learning limit has been reached, new entries will then be able to be learned until the limit is reached again.
Permanent static and permanent dynamic entries can still be added and deleted using the create fdb and disable flooding ports commands. These override any dynamically learned entries.