I recently had a problem at a client of mine where one of their DCs syncronized its clock to an ntp server which was incorrect. ( www.ntppool.org/scores/ shows the moment the time was incorrect.... an hour out). It caused problems for a few hours as that affected their building management systems which sync their clocks with the DC. In the morning lights didn't automatically switch on and aircon systems started late due to the time difference
The MS documentation says that the service will establish the most accurate clock to use as its source, but doesn't indicate if this occurs on every clock check or just once on service-startup? I always have two ntp sources configured on DCs. In this case the time service seems to have just consulted one and shifted its clock back by a full hour in one jump.
My question is, is there any way to get it to query, say, 3 ntp servers and only have it make changes if at least two of the three coincide, thus avoiding the problem of an ntp server returning a wildly incorrect value for a brief time?
