Windows server 2008 ntp server

However, if a computer has been manually configured to synchronize from a specific time source, perhaps because it was formerly not joined to a domain, you can reconfigure the computer to begin automatically sourcing its time from the domain hierarchy.

Most domain-joined computers have a time client type of NT5DS, which means that they synchronize time from the domain hierarchy. An exception to this is the domain controller, which functions as the primary domain controller PDC emulator operations master for the root forest domain. The PDC emulator operations master in turn is usually configured to synchronize time with an external time source.

You can achieve down to one-millisecond time accuracy in your domain. For more information, see Support boundary for high-accuracy time and see Accurate Time for Windows Server Don't use the Net time command to configure or set a computer's clock time when the Windows Time service is running.

This command has since been deprecated. Whenever the computer synchronizes its clock or provides time to another computer, it happens over UDP port This port is exclusively reserved by the Windows Time service. If you have a computer with multiple network adapters is multi-homed , you cannot enable the Windows Time service based on a network adapter.

You can use the command-line tool W32tm. Membership in the local Administrators group is required to run W32tm. 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. 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. February 12, at AM. Thanks for great guide.

I wan to know, how many client can use this kind of NTP server that rub by W32time? April 01, at AM. June 24, at AM. July 02, at AM.

November 10, at AM. January 22, at AM. November 11, at AM. March 09, at AM. Could you please guide me step by step configuration. April 12, at AM. May 27, at AM. Thanks a mil. May 30, at AM. June 15, at AM.

November 16, at AM. March 03, at AM. June 09, at AM. Your email address will not be published. Instructions on how to disable Skype v8 automatic updates.

Pretty sweet so far. I can finally decommis Enable NTPServer. Exit Registry Editor. Tips Make sure W32Time is set to Automatic startup mode. Make sure UDP is allowed through your firewall. Thanks for the great post with quick and clear instructions. Steve March 01, at AM I can make a Server do one or the other , but not both at once. The time service is now synchronizing the system time with the time source time. The time service has started advertising as a good time source.

What I need is a way that a and 5 are combined. Abdullah May 08, at AM also work perfectly for windows server…. Great instructions. WinAdmin December 01, at AM If you set it on the standalone W server but domain joined does it have any affect for its normal behavior when pulling time sync from the Domain Controller? Thanks so much!

Tomten May 21, at AM I cannot do the changes. 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.

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.

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