The Windows Time service makes sure that all computers in an organization that are running the Microsoft Windows Server operating system or later versions use a common time. To guarantee appropriate common time usage, the Windows Time service uses a hierarchical relationship that controls authority, and the Windows Time service does not allow for loops.
By default, Windows-based computers use the following hierarchy:. In this hierarchy, the PDC operations master at the root of the forest becomes authoritative for the organization. We highly recommend that you configure the authoritative time server to obtain the time from a hardware source.
When you configure the authoritative time server to sync with an Internet time source, there is no authentication. We also recommend that you reduce your time correction settings for your servers and stand-alone clients. These recommendations provide more accuracy and security to your domain. Feedback will be sent to Microsoft: By pressing the submit button, your feedback will be used to improve Microsoft products and services.
Privacy policy. Skip to main content. This browser is no longer supported. If that happens, you may have network issues, such as a firewall, preventing communication with the NTP server. You would run this command after making other changes to see if the issues are resolved. If the time service is simply not behaving, you can use these commands to completely re-register the service.
Note that this will remove all configuration related to Windows Time and restore it to default: Net Stop W32time W32tm. The log will contain an entry for each operation that the service performs. It can be difficult to sort through all of the information, but it can be extremely valuable to see each step in detail. If a single member server is wrong, review the System event log to determine which DCs it is trying to sync from, and ensure those DCs are working correctly.
Sometimes, a failure will cascade through the domain. A networking issue may prevent a set of DCs from syncing with the PDC, which can then cause the member servers in that network to stop as well.
You may need to trace the issues up the hierarchy. What I simply want is to declare my master fsmo domain controller to be the top authority in time service in my domain. All my domain controllers are Windows R2. I have at least one member server that is always 2 minutes off everyone else, and the Windows Time Service keeps disabling itself on this server. I want to declare DC01 as the master and I want every other DC and server and computers to use this time. DC01 is a vmware dc, and I understand virtual guests get their time from their hardware host.
While I'm on the subject, how do you set your vmware host cluster, in vcenter, to get accurate time and keep itself updated? My times are 2 minutes off the universal standard time. To summarize, I want to declare DC01 the absolute time master, and everyone else downstream should get their time from it, and all be the same time.
I'd also like to know what command I can run on a computer or server to determine where it's getting it's time from in the domain it's attached to. I don't think this has changed since Windows server really. Some of the preset GPO settings differ from the corresponding default Windows Time service registry entries. Windows loads these settings into the policy area of the registry under the following subkey:.
Then Windows uses the policy settings to configure the related Windows Time service registry entries under the following subkey:. The following table lists the policies that you can configure for the Windows Time service, and the registry subkeys that those policies affect. When you remove a Group Policy setting, Windows removes the corresponding entry from the policy area of the registry.
This information is provided as a reference for use in troubleshooting and validation. Windows registry keys are used by W32Time to store critical information. Don't change these values. Modifications to the registry are not validated by the registry editor or by Windows before they are applied. If the registry contains invalid values, Windows may experience unrecoverable errors.
Some of the parameters in the registry are measured in clock ticks and some are measured in seconds. To convert the time from clock ticks to seconds, use these conversion factors:. Note Zero is not a valid value for the FrequencyCorrectRate registry entry. HoldPeriod All versions Controls the period of time for which spike detection is disabled in order to bring the local clock into synchronization quickly.
A spike is a time sample indicating that time is off a number of seconds, and is usually received after good time samples have been returned consistently. The default value on domain members is 5. The default value on stand-alone clients and servers is 5. LargePhaseOffset All versions Specifies that a time offset greater than or equal to this value in 10 -7 seconds is considered a spike.
A network disruption such as a large amount of traffic might cause a spike. A spike will be ignored unless it persists for a long period of time. The default value on domain members is The default value on stand-alone clients and servers is It contains reserved data that is used by the Windows operating system, and any changes to this setting can cause unpredictable results. MaxAllowedPhaseOffset All versions Specifies the maximum offset in seconds for which W32Time attempts to adjust the computer clock by using the clock rate.
When the offset exceeds this rate, W32Time sets the computer clock directly. The default value for domain members is The default value for stand-alone clients and servers is 1. The default value for stand-alone clients and servers is MaxNegPhaseCorrection All versions Specifies the largest negative time correction, in seconds, that the service makes.
If the service determines that a change larger than this is required, it logs an event instead. This value means that the service always corrects the time.
The default value for stand-alone clients and servers is 54, 15 hrs. MaxPollInterval All versions Specifies the largest interval, in log2 seconds, allowed for the system polling interval. Note that while a system must poll according to the scheduled interval, a provider can refuse to produce samples when requested to do so. The default value for domain controllers is MaxPosPhaseCorrection All versions Specifies the largest positive time correction in seconds that the service makes. MinPollInterval All versions Specifies the smallest interval, in log base 2 seconds, allowed for the system polling interval.
Note that while a system does not request samples more frequently than this, a provider can produce samples at times other than the scheduled interval. The default value for domain controllers is 6. PhaseCorrectRate All versions Controls the rate at which the phase error is corrected. Specifying a small value corrects the phase error quickly, but might cause the clock to become unstable. If the value is too large, it takes a longer time to correct the phase error.
The default value on domain members is 1. The default value on stand-alone clients and servers is 7. Note Zero is not a valid value for the PhaseCorrectRate registry entry. PollAdjustFactor All versions Controls the decision to increase or decrease the poll interval for the system. The larger the value, the smaller the amount of error that causes the poll interval to be decreased.
RequireSecureTimeSyncRequests Windows 8 and later versions Controls whether or not the DC will respond to time sync requests that use older authentication protocols. If enabled set to 1 , the DC will not respond to requests using such protocols. This is a boolean setting, and the default value is 0. SpikeWatchPeriod All versions Specifies the amount of time that a suspicious offset must persist before it is accepted as correct in seconds.
The default value on stand-alone clients and workstations is TimeJumpAuditOffset All versions An unsigned integer that indicates the time jump audit threshold, in seconds. If the time service adjusts the local clock by setting the clock directly, and the time correction is more than this value, then the time service logs an audit event. UpdateInterval All versions Specifies the number of clock ticks between phase correction adjustments.
The default value for domain members is 30, The default value for stand-alone clients and servers is , Note Zero is not a valid value for the UpdateInterval registry entry.
The default value on stand-alone clients and servers is 1. The default value on stand-alone clients and servers is 0x1. The NtpServer is a time server that responds to client time requests on the network by returning time samples that are useful for synchronizing the local clock. LargeSampleSkew All versions Specifies the large sample skew for logging, in seconds. Events will be logged for this setting only when EventLogFlags is explicitly configured for 0x2 large sample skew.
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