Global Configuration Settings

These settings control the Windows Time service (W32time) for domain controllers. Several of these values are scalar, which means that they only have meaning in relation to one another and are not defined by specific unit measurements. For settings regarding time sync for domain member computers, see Configure a client computer for automatic domain time synchronization (http://go.microsoft.com/fwlink/?LinkId=139706).

Clock discipline parameters

FrequencyCorrectRate: Controls the rate at which the W32time corrects the local clock's frequency. Lower values cause slower corrections; larger values cause quicker corrections. Values that are too low can lead to overcorrection and instability. Values that are too high can lead to slow synchronization. Default: 4 (scalar).

HoldPeriod: Indicates how many potentially accurate time samples the client must receive in a series before subsequent time samples are evaluated as potential spikes. After a period of not receiving any usable time samples, a time client ceases to evaluate time samples for spikes as soon as the first potentially accurate time sample is received. When a series of time samples (as indicated by HoldPeriod) is received, the time client evaluates subsequent time samples for spikes. A time sample is considered to be a spike when the time difference between a time sample and the client's local clock is greater than that of the LargePhaseOffset value. Default: 5 time samples.

LargePhaseOffset: Specifies the time variation from the client's local clock (phase offset) that a time sample must have to be considered a spike. Time samples that have time variations larger than the LargePhaseOffset value are considered spikes. Default: 50,000,000 100-nanosecond units (ns), which is 5 seconds.

MaxAllowedPhaseOffset: Controls how W32time corrects the clock based on the size of the calculated time variation between the time sample and the client's local clock. If a response is received that has a time variation that is larger than this value, W32time sets the client's local clock immediately to the time that is accepted as accurate from the Network Time Protocol (NTP) server. If the time variation is less than this value, the client's local clock is corrected gradually. Default: 300 seconds.

MaxNegPhaseCorrection: Controls the maximum allowable clock correction that can be made in a reverse direction. If a time sample is received that indicates a time in the past (as compared to the client's local clock) that has a time difference that is greater than the MaxNegPhaseCorrection value, the time sample is discarded. If this happens, the Windows Time source logs an event in the System log of Event Viewer. Default: 172,800 seconds.

MaxPosPhaseCorrection: Controls the maximum allowable clock correction that can be made in a forward direction. If a time sample is received that indicates a time in the future (as compared to the client's local clock) that has a time difference greater than the MaxPosPhaseCorrection value, the time sample is discarded. Default: 172,800 seconds.

PhaseCorrectRate: Controls how quickly W32time corrects the client's local clock difference to match time samples that are accepted as accurate from the NTP server. Lower values cause the clock to correct more slowly; larger values cause the clock to correct more quickly. Default: 7 (scalar).

PollAdjustFactor: Controls how quickly W32time changes polling intervals. When responses are considered to be accurate, the polling interval lengthens automatically. When responses are considered to be inaccurate, the polling interval shortens automatically. Default: 5 (scalar).

SpikeWatchPeriod: Specifies the amount of time that suspicious time samples are received from a time source before these time samples are accepted as accurate. Time samples are considered suspicious when the time difference between the time sample and the client's local clock is larger than the value of LargePhaseOffset. SpikeWatchPeriod is used in conjunction with HoldPeriod to help eliminate sporadic, inaccurate time samples that are returned from a peer. Default: 900 seconds.

UpdateInterval: Specifies the amount of time that W32time waits between corrections when the clock is being corrected gradually. When it makes a gradual correction, the service adjusts the clock slightly, waits this amount of time, and then checks to see if another adjustment is needed, until the correction is finished. Default: 100 1/100th second units, which is 1 second.

General parameters:

AnnounceFlags: A bitmask value that controls how time service availability is advertised through NetLogon. Default: 0x0a hexadecimal. For possible values, see Config\AnnounceFlags Entry (http://go.microsoft.com/fwlink/?LinkId=139718).

EventLogFlags: Controls special events that may be logged to the Event Viewer System log. Default: 0x02 hexadecimal bitmask. For possible values, see NtpClient\EventLogFlags Subkey (http://go.microsoft.com/fwlink/?LinkId=139720).

LocalClockDispersion: Indicates the maximum error in seconds that is reported by the NTP server to clients that are requesting a time sample. (Applies only when the NTP server is using the time of the local CMOS clock.) Default: 10 seconds.

MaxPollInterval: Controls the maximum polling interval, which defines the maximum amount of time between polls of a peer. Default: 10 in log base-2, which is 1,024 seconds. (Should not be set higher than 15.)

MinPollInterval: Controls the minimum polling interval that defines the minimum amount of time between polls of a peer. Default: 6 in log base-2, which is 64 seconds.

RODC parameters:

For additional information about these settings, see Appendix A: Technical Reference Topics (http://go.microsoft.com/fwlink/?LinkID=128273).

ChainEntryTimeout: 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. Default: 16 seconds.

ChainMaxEntries: 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. Default: 128 entries.

ChainMaxHostEntries: Controls the maximum number of entries that are allowed in the chaining table for a particular host. Default: 4 entries.

ChainDisable: Controls whether or not the chaining mechanism is disabled. If chaining is disabled (set to 0), the 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. Default: 0 Boolean.

ChainLoggingRate: 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. Default: 30 minutes.


Supported on: At least Windows Server 2003 operating systems or Windows XP Professional

Clock Discipline Parameters

FrequencyCorrectRate

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Microsoft\W32Time\Config
Value NameFrequencyCorrectRate
Value TypeREG_DWORD
Default Value4
Min Value1
Max Value
HoldPeriod

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Microsoft\W32Time\Config
Value NameHoldPeriod
Value TypeREG_DWORD
Default Value5
Min Value1
Max Value
LargePhaseOffset

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Microsoft\W32Time\Config
Value NameLargePhaseOffset
Value TypeREG_DWORD
Default Value50000000
Min Value
Max Value4294967295
MaxAllowedPhaseOffset

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Microsoft\W32Time\Config
Value NameMaxAllowedPhaseOffset
Value TypeREG_DWORD
Default Value300
Min Value
Max Value
MaxNegPhaseCorrection

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Microsoft\W32Time\Config
Value NameMaxNegPhaseCorrection
Value TypeREG_DWORD
Default Value172800
Min Value
Max Value4294967295
MaxPosPhaseCorrection

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Microsoft\W32Time\Config
Value NameMaxPosPhaseCorrection
Value TypeREG_DWORD
Default Value172800
Min Value
Max Value4294967295
PhaseCorrectRate

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Microsoft\W32Time\Config
Value NamePhaseCorrectRate
Value TypeREG_DWORD
Default Value1
Min Value1
Max Value
PollAdjustFactor

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Microsoft\W32Time\Config
Value NamePollAdjustFactor
Value TypeREG_DWORD
Default Value5
Min Value1
Max Value
SpikeWatchPeriod

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Microsoft\W32Time\Config
Value NameSpikeWatchPeriod
Value TypeREG_DWORD
Default Value900
Min Value1
Max Value
UpdateInterval

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Microsoft\W32Time\Config
Value NameUpdateInterval
Value TypeREG_DWORD
Default Value100
Min Value1
Max Value4294967295

General Parameters

AnnounceFlags

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Microsoft\W32Time\Config
Value NameAnnounceFlags
Value TypeREG_DWORD
Default Value10
Min Value
Max Value16
EventLogFlags

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Microsoft\W32Time\Config
Value NameEventLogFlags
Value TypeREG_DWORD
Default Value2
Min Value
Max Value3
LocalClockDispersion

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Microsoft\W32Time\Config
Value NameLocalClockDispersion
Value TypeREG_DWORD
Default Value10
Min Value
Max Value16
MaxPollInterval

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Microsoft\W32Time\Config
Value NameMaxPollInterval
Value TypeREG_DWORD
Default Value10
Min Value
Max Value
MinPollInterval

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Microsoft\W32Time\Config
Value NameMinPollInterval
Value TypeREG_DWORD
Default Value6
Min Value
Max Value15
ChainEntryTimeout

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Microsoft\W32Time\Config
Value NameChainEntryTimeout
Value TypeREG_DWORD
Default Value16
Min Value2
Max Value16
ChainMaxEntries

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Microsoft\W32Time\Config
Value NameChainMaxEntries
Value TypeREG_DWORD
Default Value128
Min Value128
Max Value1024
ChainMaxHostEntries

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Microsoft\W32Time\Config
Value NameChainMaxHostEntries
Value TypeREG_DWORD
Default Value4
Min Value1
Max Value4
ChainDisable

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Microsoft\W32Time\Config
Value NameChainDisable
Value TypeREG_DWORD
Default Value0
Min Value0
Max Value1
ChainLoggingRate

Registry HiveHKEY_LOCAL_MACHINE
Registry PathSoftware\Policies\Microsoft\W32Time\Config
Value NameChainLoggingRate
Value TypeREG_DWORD
Default Value30
Min Value0
Max Value10080

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