Looking for an Utility Date &Time Sync

I’m in the need to find something that synchronize five the clock of 5 pc running with Dos as OS with anyone of my server present in my LAN. I have to insert this subroutine in some programs of dialog to industrial PLC. If there isn’t a subroutine (part of code lines to insert in a program) I’m looking for an utility software to launch from the command prompt (i.e a batch script or so…).
Tks.
Andy