Global Configuration Settings

This policy setting allows you to specify Clock discipline and General values for the Windows Time service (W32time) for domain controllers including RODCs. If you enable this policy setting you can specify the following Clock discipline General and RODC parameters for this service. If you disable or do not configure this policy setting Windows Time service uses the defaults of each of the following parameters. Several of the following values are scalar which means that they only have meaning in relation to one another and are not defined by specific unit measurements. FrequencyCorrectRateThis parameter controls the rate at which the W32time corrects the local clock’s frequency. Lower values cause slower corrections; larger values cause more frequent 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). HoldPeriodThis parameter indicates how many potentially accurate time samples the client computer 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 computer’s local clock is greater than that of the LargePhaseOffset value. Default: Five time samples. LargePhaseOffsetThis parameter specifies the time variation from the client computer’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: 50000000 100-nanosecond units (ns) which is five seconds. MaxAllowedPhaseOffsetThis parameter controls how W32time corrects the clock based on the size of the calculated time variation between the time sample and the client computer’s local clock. If a response is received that has a time variation that is larger than this value W32time sets the client computer’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 computer’s local clock is corrected gradually. Default: 300 seconds. MaxNegPhaseCorrectionThis parameter 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 computer’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: 172800 seconds. MaxPosPhaseCorrectionThis parameter 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 computer’s local clock) that has a time difference greater than the MaxPosPhaseCorrection value the time sample is discarded. Default: 172800 seconds. PhaseCorrectRateThis parameter controls how quickly W32time corrects the client computer’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). PollAdjustFactorThis parameter 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). SpikeWatchPeriodThis parameter 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 computer’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. UpdateIntervalThis parameter 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:AnnounceFlagsThis parameter is a bitmask value that controls how time service availability is advertised through NetLogon. Default: 0x0a hexadecimal. See the NtpClient -> EventLogFlags Subkey documentation on Microsoft’s TechNet Library for possible values. EventLogFlagsThis parameter controls special events that may be logged to the Event Viewer System log. Default: 0x02 hexadecimal bitmask. See the NtpClient -> EventLogFlags Subkey documentation on Microsoft’s TechNet Library for possible values. LocalClockDispersionThis parameter 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. MaxPollIntervalThis parameter 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 1024 seconds. (Should not be set higher than 15. )MinPollIntervalThis parameter 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. RequireSecureTimeSyncRequestsThis parameter controls whether or not the the DC will respond to time sync requests that use older authentication protocols. If enabled (set to 1) the DC will not respond to requests using such protocols. Default: 0 Boolean. RODC parameters:ChainEntryTimeoutThis parameter 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. ChainMaxEntriesThis parameter 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. ChainMaxHostEntriesThis parameter controls the maximum number of entries that are allowed in the chaining table for a particular host. Default: 4 entries. ChainDisableThis parameter 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. ChainLoggingRateThis parameter 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.