Allied Telesis AT-S63 - Manual (Page 282)

Chapter 25: Spanning Tree and Rapid Spanning Tree Protocols
282 Section V: Spanning Tree Protocols
 BPDU guard is supported only on RSTP. It is not supported on STP or
MSTP.
 This feature is supported on the base ports of the switch and any
expansion modules and fiber optic transceivers installed in the unit.
Note
A port that the BPDU guard feature has disabled remains in that state
until you enable it with the management software. If a port is still
receiving BPDUs, you should disconnect the network cable before
enabling it to prevent the feature from disabling the port again.