LM5158: zener diode needed for master

Part Number: LM5158

Tool/software:

on behalf of my customer: 

The LM5158 is used as a 48V PoE supply for the master (24V --> 48V). With PoE, there is a voltage limitation at 57V. In many PoE Slave designs
I see a 58V Zener diode to limit the maximum voltage. Do you know how this is handled with the master, is the master also required to limit the voltage?