Why Clients obtain a windows time from not PDC Server


Recently i transferred my PDC server to a new one, now i found clients update a time from differnets DC not from PDC server.

some clients obtain from DC1 and some from DC2
Abdulrhman AlamoudiAsked:
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Hello ThereSystem AdministratorCommented:
Use w32tm commands:

net stop w32time
net start w32time
w32tm /config /manualpeerlist:,0x8 /syncfromflags:MANUAL /reliable:yes /update
w32tm /resync /rediscover
net stop w32time
net start w32time

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Create a batch file and run it on all machines.
Peter HutchisonSenior Network Systems SpecialistCommented:
By default domain computers with pick up the time from the Domain Controller with the PDC FSMO role.
You need to configure the PDC as a NTP reliable source server, clients that are configured as Server type NT5DS will auto use the PDC as their time source. To configure your new PDC (change the time source to one that you use). There is no need to change all client machines.

w32tm /config /manualpeerlist:"ntp.domain.com,0x1 " /syncfromflags:manual /reliable:yes /update
net stop w32time
net start w32time

On the old DC, change it to a non-reliable time source:
w32tm /config /syncfromflags:domhier /reliable:no /update
net stop w32time
net start w32time
this is not issue as far as I can tell

DC can obtain time from other DCs in same site apart from PDC and even clients can obtain time from other DCs in same site

PDC is authoritative time source which can obtain time from external time source or any internal time source or can be declare itself as reliable time source

as long as time is in sync across DCs and clients I don't see any issue
Cliff GaliherCommented:
This is by design.  In a large network, 100,000 clients hitting the PDC would cripple it. Not to mention WAN links introduce latency and an assortment of problems.  

By default when a domain is in play, windows uses the "domain hierarchy" as a time source.  The PDC is the authoritative time server, but from there, other DCs can provide time sources to member servers and clients, and even other DCs.  Diagrammed, it is a multi-level branching tree with the PDC at the top.  Clients getting timing from another DC is totally normal.
DrDave242Senior Support EngineerCommented:
Other experts have already answered the question, so I don't need points for this. The idea that everything in a domain gets time straight from the PDC Emulator is a common misconception, though, so here's the diagram that Cliff referred to:

Windows Time Service Hierarchy in AD
Source: How the Windows Time Service Works

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