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PDC not syncing to external NTP!?

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Last Modified: 2018-08-28
I'm trying to get my DC (with the PDC Emulator role) to sync its time to an external NTP server but it simply doesn't stick!? It simply continues to use the local CMOS clock as a source??

I've executed these commands: https://community.spiceworks.com/how_to/65413-configure-dc-to-synchronize-time-with-external-ntp-server

I've tested this: w32tm /stripchart /computer:NTPServerNameOrIP /dataonly /samples:x and I get answers back

But the PDC simply doesn't keep the external NTP server as a source and thus doesn't synchronize the time correctly ... what's up with this!?

Thanks!
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Dr. KlahnPrincipal Software Engineer
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Commented:
But the PDC simply doesn't keep the external NTP server as a source

Does this happen while the system is still running, or after a reboot?

Have you examined the Registry after setting the server parameters to confirm that the Registry has been set?

Is the Windows Time Service set to run at startup?
Pete LongTechnical Architect
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Commented:
If you run the resync command do either of the correct Even ID's show up in the Event Log?

See my post here
Windows – Setting Domain Time



Pete

Author

Commented:
Pete:

I've done what's described on that page you've linked to and I get this in the event viewer:

EventID 12: Time Provider NtpClient: This machine is configured to use the domain hierarchy to determine its time source, but it is the AD PDC emulator for the domain at the root of the forest, so there is no machine above it in the domain hierarchy to use as a time source. It is recommended that you either configure a reliable time service in the root domain, or manually configure the AD PDC to synchronize with an external time source. Otherwise, this machine will function as the authoritative time source in the domain hierarchy. If an external time source is not configured or used for this computer, you may choose to disable the NtpClient.
Pete LongTechnical Architect
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>>I've done what's described on that page you've linked to and I get this in the event viewer:

is UDP port 123 open on your firewall? Did you see Event ID 37 and 35.

Author

Commented:
Wait, I missed something ... after the resync command I get an error: 'the computer did not resync because no time data was available'.

UDP port 123 is open on the main firewall, will have to check on Windows firewall on the server ...

Author

Commented:
I've added an inbound and an outbound rule for port 123 but that doesn't seem to help ...

Also, this still works: w32tm /stripchart /computer:NTPServerNameOrIP /dataonly /samples:x  and I see the NTP requests on my firewall.

The problem seems to be that the DC doesn't know where to look for time data even though I have entered those other commands ...
Pete LongTechnical Architect
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>>I've added an inbound and an outbound rule for port 123 but that doesn't seem to help ...

You only need an outbound rule from the PDC, allow to anywhere (for now)

Then issue the same command I posted on my site including the NTP server (Manchester university - I always use this, its always up, and we can change it later if you like)

Then, Check the server server is not getting time settings from Group Policy (see link above)

Author

Commented:
I've executed w32tm /config /manualpeerlist:ntp2d.mcc.ac.uk /syncfromflags:manual /reliable:yes /update on the PDC and it tells me: 'the command completed successfully'.

But when I execute w32tm /query /configuration it is still pointing to local sources ...

Here's a log file though, maybe that'll help you?

Group Policy elements are on 'not configured'
w32time.log

Author

Commented:
I keep getting this error in the Event Viewer: Time Provider NtpClient: This machine is configured to use the domain hierarchy to determine its time source, but it is the AD PDC emulator for the domain at the root of the forest, so there is no machine above it in the domain hierarchy to use as a time source. It is recommended that you either configure a reliable time service in the root domain, or manually configure the AD PDC to synchronize with an external time source. Otherwise, this machine will function as the authoritative time source in the domain hierarchy. If an external time source is not configured or used for this computer, you may choose to disable the NtpClient.
Pete LongTechnical Architect
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Is this a virtual server? Make sure either VMware tools or whatever the Microsoft equiv is called is NOT set to sync time from the Hypervisor.

lets make sure its set to defaults

Configure authorative time server on the PDC role holder server below is the KB article for the same.
http://support.microsoft.com/kb/816042
Make sure that below parameters are set correctly on PDC Server.
1.Change the server type to NTP
2.Set AnnounceFlags to 5
3.Enable NTPServer
4.Specify the time sources.eg time.windows.com,0x1 or pool.ntp.org,0x1
5Configure other paratmeters as well.
Restart the windows time service.Ran w32tm /resync /rediscover command.
Check the system log you will get event id 35 and 37 related to time sync.

Author

Commented:
Yes, it's a VMWare virtual server ... gonna check the tools then

Author

Commented:
Hm, the time of the VM is not being synchronized with the host.

Author

Commented:
I've done all of those things again ... I'm still getting the 'the computer did not resync because no data was available'.

w32tm /query /configuration still points to local sources ... not the external NTP servers!?

Author

Commented:
that PNG file seems corrupt?
Pete LongTechnical Architect
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Commented:
take 2
I forced that to happen by blocking UDP 123 on the firewall

UDP-123-Blocked
Pete LongTechnical Architect
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Commented:
try NTP tools if you get no received packets like this then thats your problem

ntp tool
Pete LongTechnical Architect
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Commented:
Look what happens when I take that firewall rule out and open udp 123

Boom

Author

Commented:
Pete: that's what I'm getting when I use NTPTool!

But I still get the 'the computer did not resync because no time data was available' when trying to execute 'w32tm /resync' ...

Author

Commented:
I think I'll simply give up on this issue ... I've now enabled NTP Sync on the VMWare host and it's syncing its (correct!) time to the VMs of the Domain Controllers using VMWare tools.
Pete LongTechnical Architect
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Commented:
Thats not a good solution one dodgy host CMOS battery and your Domain controllers can start tombstoning each other :(

Author

Commented:
Hm ... yeah, good point ... but I don't seem to be able to get time to sync on my ADs!?
Technical Architect
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This problem has been solved!
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Author

Commented:
Yessssssssssss, it has finally worked! The problem was that there was a 'default group policy' that contained bad parameters for all that NTP stuff. I've removed those parameters and then applied your article and everything works fine now :)

Thanks again! That Resultant Set of Policy was key!
Pete LongTechnical Architect
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Commented:
OK - Im putting together how to configure the PDC via GPO as we speak :)
Pete LongTechnical Architect
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