Windows ntp announceflags

Set client to use two time servers To set a client computer to point to two different time servers, one named ntpserver. To configure a client computer that is currently synchronizing time using a manually-specified computer to synchronize time automatically from the AD domain hierarchy, run the following following:. To check a client configuration from a Windows-based client computer that has a host name of contosoW1 , run the following command:.

The output of this command displays a list of W32time configuration parameters that are set for the client. Windows Server has improved the time synchronization algorithms to align with RFC specifications.

Therefore, if you want to set the local time client to point to multiple peers, we recommended that you prepare three or more different time servers. If you have only two time servers, you should specify the Ntpserver UseAsFallbackOnly flag 0x2 to de-prioritize one of them. For example, if you want to prioritize ntpserver.

Additionally, you can run the following command and read the value of NtpServer in the output:. In order for W32tm. Then, to adjust the computer clock by using the clock rate, W32tm.

This algorithm varies depending on the version of Windows:. MaxAllowedPhaseOffset is configurable in the registry. However, the registry parameter is measured in seconds instead of clock ticks.

This command produces output that resembles the following. The output presents the poll interval in both clock ticks and in seconds. The equations use the value measured in seconds the value in parentheses. The output presents the clock rate in seconds. To see the SystemClockRate value in clock ticks, use the following formula:.

For example, if SystemClockRate is 0. For full descriptions of the configurable parameters and their default values, see Config entries later in this article. The following examples show how to apply these calculations for Windows Server R2 and earlier versions. In this case, if you want to set the clock back slowly, you would also have to adjust the values of PhaseCorrectRate or UpdateInterval in the registry to make sure that the equation result is TRUE.

The Windows Time service stores a number of configuration properties as registry entries. It stores configuration information that the policies define in the Windows registry, and then uses those registry entries to configure the registry entries specific to the Windows Time service.

As a result, the values defined by Group Policy overwrite any pre-existing values in the Windows Time service section of the registry. 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 domain controllers is , 48 hrs.

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 , Once extended support runs out - it will have to be upgraded.

Get answers from your peers along with millions of IT pros who visit Spiceworks. Best Answer. LarryCK wrote: however, one of the links that supposedly gives the answer is dead and the other one does not seem to mention NTP protocol version anywhere. If you need full ntp compliance , you may choose other implementations, including the reference implementation. As far as I remember, the reference implementation for ntp v4 is available for Windows , including Windows Server R2 and Windows Server There are instructions how to integrate that reference implementation into Windows.

The above mentioned Wikipedia article also mentions that this reference implementation has been audited in and several security issues found. I don't know to which extent this fixes have been addressed since. Its latest update is of June And if you need high network time accuracy, there exist other protocol standards which are available also for Windows.

But be aware that if you have such requirements, you'll also have an instruction manual how to setup and configure your instances of operating system and applications. It doesn't make sense to use a high precision protocol when a general purpose configuration of Windows will not guarantee availability of access to that accurate time over all the time.

The idea for such instructions is to define and configure a subsystem where this access remains available and soften the access on less time critical components. View this "Best Answer" in the replies below ».

Popular Topics in Windows Server. Which of the following retains the information it's storing when the system power is turned off? Submit ». Pure Capsaicin. Gary D Williams This person is a verified professional.

Verify your account to enable IT peers to see that you are a professional. PatrickFarrell This person is a verified professional.

Windows Server expert. Gary D Williams Pure Capsaicin. PatrickFarrell Mace. As I said above, you can safely go with version 3. In what sort of audit would the NTP version matter? The easiest way to get this might be to open and pay for a support ticket with microsoft.

Gary D Williams wrote: The easiest way to get this might be to open and pay for a support ticket with microsoft. Thai Pepper. It's their own implementation - you can check configuration as follows: Powershell. LarryCK Serrano. LarryCK wrote: It is for the audit. What is outdated? What legacy mode? What comes close to a subset? Each DNS name that is listed must be unique. You must append ,0x1 to the end of each DNS name. If you do not append ,0x1 to the end of each DNS name, the changes that you make in step 5 will not take effect.

TimeInSeconds is a placeholder for a reasonable value, such as 1 hour or 30 minutes The value that you select will depend on the poll interval, network condition, and external time source. At the command prompt, type the following command to restart the Windows Time service, and then press Enter:. For the Windows Time service to function correctly, the networking infrastructure must function correctly. The most common problems that affect the Windows Time service include the following:. We recommend that you use the Netdiag.

See Tools Help for a complete list of command-line parameters that you can use with Netdiag. If your problem is still not solved, you can turn on the Windows Time service debug log. Because the debug log can contain very detailed information, we recommend that you contact Microsoft Customer Support Services when you turn on the Windows Time service debug log.

In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

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.