To disable an interface when the number of learned MAC addresses exceeds a specified limit, Port Security must be configured on the relevant port-channel interface. - Port Security allows the administrator to limit the number of MAC addresses that can be dynamically learned on an interface. - When the limit is exceeded, the interface can be configured to shut down automatically (err- disable state). - In this topology, Po100 connects to Server S1, meaning MAC address limitations should be enforced on Po100 to protect the network.