Note, Microsoft explicitly states it does not guarantee the accuracy of the service, as it is used for Kerberos purposes which only requires synchronisation accuracy of 5 minutes. However I have found it to work reasonable for my dev machine. For more info, see Microsoft KB Open the registry and navigate to:. The NTP service should now be setup. The final step is to allow the service through the firewall. Open Windows Firewall Settings. Click Inbound Rules. You should now be able to access the time server.
Here is the command to test it from Ubuntu:. How can I access this local server from outside on the network embedded board? Like Like. Hello sir. How can I enable it? What I have to do sir.? Thanks for sharing. Very clear and informative. 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.
The default value for stand-alone clients and servers is One of those situations is a non-domain joined server. Another common need is to create a standalone NTP server that can provide time synchronization for unjoined Windows computers as well as other operating systems like Linux and Mac OSX. The service is off by default.
So configuring a system as an NTP server requires both enabling the W32Time service and configuring it as a server. The process is very simple. First, use the Services console to locate the Windows Time service. It will likely be off as shown in Figure 1. Figure 2. The W32Time service is started and configured for automatic start. Enabling the NTP server service requires a quick registry modification.
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