Allied Telesis AT-S79 - Manual (Page 188)

Chapter 16: Destination MAC Filtering
188 Section I: Using the Menus Interface
Destination MAC Filtering Overview
Destination MAC Filtering is a security feature that applies to the AT-
GS950 switches. It prevents AT-GS950/16 and AT-GS950/24 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-GS950 switch drops or discards
packets sent from this device.
To reverse this process and allow an AT-GS950 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.