Windows server sync with ntp

Not an IT pro? Windows Server TechCenter. Sign in. United States English. Ask a question. Quick access. Search related threads. Remove From My Forums. Answered by:. Post as a guest Name. Email Required, but never shown. The Overflow Blog. Stack Gives Back Safety in numbers: crowdsourcing data on nefarious IP addresses. Featured on Meta. New post summary designs on greatest hits now, everywhere else eventually.

Visit chat. Linked 2. Related Hot Network Questions. Question feed. Stack Overflow works best with JavaScript enabled. Accept all cookies Customize settings. When peer-to-peer networking is employed, each individual workstation sync to a time reference independently. All other servers and workstations in the domain sync to the PDC using Windows proprietary protocol. The default installation procedure automatically configures workstations and servers to sync to the controlling PDC.

Only the PDC needs to be configured to synchronize to an external time reference. When modifying registry settings, it is always a good idea to backup the current settings beforehand. You can revert back to previous settings if any problems occur with registry changes. Change the server type to NTP. This option might be used more than once. Computer names are separated by commas, with no spaces.

The default value is 3. The allowed range is If not specified, the local computer will resynchronize. Otherwise, wait for resynchronization to complete before returning. This is used for compatibility purposes. The default is 2 seconds. If not specified, the default is the local computer. When specifying multiple peers, this option must be enclosed in quotes. This setting is only meaningful on domain controllers.

YES : This computer is a reliable time service. NO : This computer is not a reliable time service. If not specified, the default value is the local computer. In verbose mode, display the undefined or unused setting too. Valid values are 0 to A range of numbers is valid, in addition to single numbers, such as ,, Value is for logging all information.

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.