Automatic time server 0x Always-reliable time server 0x Automatic reliable time server The default value for domain members is Controls whether or not the chaining mechanism is disabled. If chaining is disabled set to 0 , a read-only domain controller RODC can synchronize with any domain controller, but hosts that do not have their passwords cached on the RODC will not be able to synchronize with the RODC.
Specifies the maximum amount of time that an entry can remain in the chaining table before the entry is considered to be expired. Expired entries may be removed when the next request or response is processed. The default value is 16 seconds. Controls the frequency at which an event that indicates the number of successful and unsuccessful chaining attempts is logged to the System log in Event Viewer.
The default is 30 minutes. Controls the maximum number of entries that are allowed in the chaining table. If the chaining table is full and no expired entries can be removed, any incoming requests are discarded.
The default value is entries. Controls the maximum number of entries that are allowed in the chaining table for a particular host. The default value is 4 entries. Specifies the smallest local clock adjustments that may be logged to the W32time service event log on the target computer. The default value is parts per million - PPM. Indicates the maximum number of seconds a system clock can nominally hold its accuracy without synchronizing with a time source. If this period of time passes without W32time obtaining new samples from any of its input providers, W32time initiates a rediscovery of time sources.
Default: 7, seconds. Controls which events that the time service logs. Time jump 0x2. Source change The default value on domain members is 2. The default value on stand-alone clients and servers is 2.
Controls the rate at which the clock is corrected. If this value is too small, the clock is unstable and overcorrects. If the value is too large, the clock takes a long time to synchronize. The default value on domain members is 4. The default value on stand-alone clients and servers is 4. Controls the period of time for which spike detection is disabled in order to bring the local clock into synchronization quickly. Specifies that a time offset greater than or equal to this value in 10 -7 seconds is considered a spike.
Maintained by W32Time. Controls the dispersion in seconds that you must assume when the only time source is the built-in CMOS clock. Specifies the maximum offset in seconds for which W32Time attempts to adjust the computer clock by using the clock rate.
Specifies the largest negative time correction, in seconds, that the service makes. Specifies the largest interval, in log2 seconds, allowed for the system polling interval. Specifies the largest positive time correction in seconds that the service makes.
Specifies the smallest interval, in log base 2 seconds, allowed for the system polling interval. Controls the rate at which the phase error is corrected. Controls the decision to increase or decrease the poll interval for the system. Controls whether or not the DC will respond to time sync requests that use older authentication protocols.
Specifies the amount of time that a suspicious offset must persist before it is accepted as correct in seconds. An unsigned integer that indicates the time jump audit threshold, in seconds. Specifies the number of clock ticks between phase correction adjustments. Value of 1 indicates that W32Time uses multiple SSL timestamps to seed a clock that is grossly inaccurate.
Indicates that non-standard mode combinations are allowed in synchronization between peers. The default value for domain members is 1. Specifies a space-delimited list of peers from which a computer obtains time stamps, consisting of one or more DNS names or IP addresses per line.
Computers connected to a domain must synchronize with a more reliable time source, such as the official U. The default value on stand-alone clients and servers is time. Indicates which peers to accept synchronization from: NoSync.
The time service does not synchronize with other sources. The time service synchronizes from the servers specified in the NtpServer. The time service synchronizes from the domain hierarchy. The time service uses all the available synchronization mechanisms. The default value on domain members is NT5DS. The default value on stand-alone clients and servers is NTP.
The default value for stand-alone clients and servers is 0x Determines whether the service chooses synchronization partners outside the domain of the computer. The default value for domain members is 2.
The default value for stand-alone clients and servers is 2. Specifies the location of the DLL for the time provider. Indicates if the NtpClient provider is enabled in the current Time Service. Run the following commands from a command prompt:.
Using the registry, disable time synchronization with the host:. To synchronize time with an external source, you must configure your domain controller with the PDC Emulator role. Select this GPO and switch to the Edit mode. Connect and share knowledge within a single location that is structured and easy to search. I am working on windows 7. I can sync time of win7 from a ntp linux server manually. How can I do that in command prompt. So I can run it on windows startup. And windows task plan not work for me.
The time should be like this:. If you just need to resync windows time, open an elevated command prompt and type:.
When "down to the millisecond" matters, however, I found that Windows wouldn't actually make the adjustment; as if "oh, I'm off by 2. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. However, the Windows Time Service can be configured to request time from a designated reference time source, and can also provide time to clients.
The degree to which a computer's time is accurate is called a stratum. The most accurate time source on a network such as a hardware clock occupies the lowest stratum level, or stratum one. This accurate time source is called a reference clock. An NTP server that acquires its time directly from a reference clock occupies a stratum that is one level higher than that of the reference clock. Resources that acquire time from the NTP server are two steps away from the reference clock, and therefore occupy a stratum that is two higher than the most accurate time source, and so on.
As a computer's stratum number increases, the time on its system clock may become less accurate. Therefore, the stratum level of any computer is an indicator of how closely that computer is synchronized with the most accurate time source.
When the W32Time Manager receives time samples, it uses special algorithms in NTP to determine which of the time samples is the most appropriate for use. The time service also uses another set of algorithms to determine which of the configured time sources is the most accurate. When the time service has determined which time sample is best, based on the above criteria, it adjusts the local clock rate to allow it to converge toward the correct time.
If the time difference between the local clock and the selected accurate time sample also called the time skew is too large to correct by adjusting the local clock rate, the time service sets the local clock to the correct time. This adjustment of clock rate or direct clock time change is known as clock discipline. The Windows Time Service Manager is responsible for initiating the action of the NTP time providers included with the operating system.
The Windows Time Service Manager controls all functions of the Windows Time service and the coalescing of all time samples. In addition to providing information about the current system state, such as the current time source or the last time the system clock was updated, the Windows Time Service Manager is also responsible for creating events in the event log. These time samples are then passed to the Windows Time Service Manager, which collects all the samples and passes them to the clock discipline subcomponent.
The clock discipline subcomponent applies the NTP algorithms which results in the selection of the best time sample.
The clock discipline subcomponent adjusts the time of the system clock to the most accurate time by either adjusting the clock rate or directly changing the time. If a computer has been designated as a time server, it can send the time on to any computer requesting time synchronization at any point in this process. Time protocols determine how closely two computers' clocks are synchronized.
A time protocol is responsible for determining the best available time information and converging the clocks to ensure that a consistent time is maintained on separate systems.
NTP is an Internet time protocol that includes the discipline algorithms necessary for synchronizing clocks. NTP is a fault-tolerant, highly scalable time protocol and is the protocol used most often for synchronizing computer clocks by using a designated time reference. NTP time synchronization takes place over a period of time and involves the transfer of NTP packets over a network. NTP packets contain time stamps that include a time sample from both the client and the server participating in time synchronization.
NTP relies on a reference clock to define the most accurate time to be used and synchronizes all clocks on a network to that reference clock. UTC is independent of time zones and enables NTP to be used anywhere in the world regardless of time zone settings.
NTP includes two algorithms, a clock-filtering algorithm and a clock-selection algorithm, to assist the Windows Time service in determining the best time sample. The clock-filtering algorithm is designed to sift through time samples that are received from queried time sources and determine the best time samples from each source. The clock-selection algorithm then determines the most accurate time server on the network. This information is then passed to the clock discipline algorithm, which uses the information gathered to correct the local clock of the computer, while compensating for errors due to network latency and computer clock inaccuracy.
The NTP algorithms are most accurate under conditions of light-to-moderate network and server loads. As with any algorithm that takes network transit time into account, NTP algorithms might perform poorly under conditions of extreme network congestion.
The Windows Time service is a complete time synchronization package that can support a variety of hardware devices and time protocols. To enable this support, the service uses pluggable time providers. A time provider is responsible for either obtaining accurate time stamps from the network or from hardware or for providing those time stamps to other computers over the network.
The NTP provider is the standard time provider included with the operating system. NtpServer output provider. This is a time server that responds to client time requests on the network. NtpClient input provider. This is a time client that obtains time information from another source, either a hardware device or an NTP server, and can return time samples that are useful for synchronizing the local clock. Although the actual operations of these two providers are closely related, they appear independent to the time service.
Starting with Windows Server, when a Windows computer is connected to a network, it is configured as an NTP client. Also, computers running the Windows Time service only attempt to synchronize time with a domain controller or a manually specified time source by default.
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