Allied Telesis AT-S80 - Manual (Page 182)

Chapter 16: Destination MAC Filter
182 Section I: Using the Menus Interface
Destination MAC Filtering Overview
Destination MAC Filtering is a security feature that prevents AT-FS750/16
or AT-FS750/24 switches from receiving packets from a particular device
which is specified by its MAC address. After you add a MAC address of a
device to the list of Destination MAC Filtering, then the AT-FS750 switch
drops or discards packets sent from this device.
To reverse this process and allow an AT-FS750 switch to receive packets
from a device on the Destination MAC Filtering list, you must remove the
MAC address of the device from the list.
Note
By default, Destination MAC Filtering is disabled on the switch.