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Robert Premuž

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Hi!

I have a problem with time synchronization on a MS Windows Server 2003 SP2.

In the Windows domain there are two DCs (both Windows Server 2003 SP2).
Their Windows Time Services (W32Time) are set as follows (I used
advice in
http://technet2.microsoft.com/windo...e5f7-41b3-b0e8-240f8236e2101033.mspx?mfr=true ):

The DC1 (has PDC role) synchronizes time with two NTP servers on the
Internet (zg1.ntp.carnet.hr and zg2.ntp.carnet.hr). I set this using
the following commands:

w32tm /config /update /manualpeerlist:"zg1.ntp.CARNet.hr,0x8
zg2.ntp.CARNet.hr,0x8" /syncfromflags:manual /reliable:yes
net stop w32time
net start w32time
w32tm /resync /rediscover

The DC2 synchronizes time with DC1. I set this using the following commands:

w32tm /config /update /syncfromflags:domhier /reliable:no
net stop w32time
net start w32time
w32tm /resync /rediscover

(Workstations synchronizes time with the domain, i.e. with DC1.)

After these settings I notice messages in the System Event Log of DC2
which show that the Time Service had to make a discontinuous change in
the system clock. This event happens approximately every 3 hours. Here
is an example of a series of events that are logged:

Event Type: Warning
Event Source: W32Time
Event Category: None
Event ID: 51
Date: 15.10.2007
Time: 22:40:55
Computer: DC2
Description:
Time Provider NtpClient: The time sample received from peer
DC1.foo.bar (ntp.d|192.168.1.13:123->192.168.1.11:123) differs from
the local time by 9 seconds. The observed transmission delay from the
server was 0 milliseconds.

Event Type: Warning
Event Source: W32Time
Event Category: None
Event ID: 50
Date: 15.10.2007
Time: 22:41:09
Computer: DC2
Description:
The time service detected a time difference of greater than 5000
milliseconds for 900 seconds. The time difference might be caused by
synchronization with low-accuracy time sources or by suboptimal
network conditions. The time service is no longer synchronized and
cannot provide the time to other clients or update the system clock.
When a valid time stamp is received from a time service provider, the
time service will correct itself.

Event Type: Warning
Event Source: W32Time
Event Category: None
Event ID: 51
Date: 15.10.2007
Time: 22:58:00
Computer: DC2
Description:
Time Provider NtpClient: The time sample received from peer
DC1.foo.bar (ntp.d|192.168.1.13:123->192.168.1.11:123) differs from
the local time by 12 seconds. The observed transmission delay from the
server was 15 milliseconds.

Event Type: Warning
Event Source: W32Time
Event Category: None
Event ID: 33
Date: 15.10.2007
Time: 22:58:25
Computer: DC2
Description:
The time service has made a discontinuous change in the system clock.
The system time has been changed by +11 seconds.

People that are familiar with NTP servers on Unix systems gave me the
following explanation of the problem: the hardware clock frequency on
DC2 has error (about 0,1 %) but the Windows Time service cannot take
the clock drift into account (as a NTP server on Unix). It can only
correct system time by discontinuous changes.

Can someone comment on this? Are there some settings for Windows Time
service that can solve this problem?

TIA

-- rpr. /Robert Premuž/
 

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