Question

Setting up a NTP server

Asked by: Emileneth

I've tried to setup a reliable fast sync server in my domain controler using several .org ntp public servers but seems i cant find a way to achieve this 3 things

A) Set my domain controller's ntp client to sync with any .org servers every 10~15 sec

B) Set my NTP server to respond every secs. Clients dont have a timestamp availabe at such speed

C) Set my workstation's ntp client to sync with my DC every 15 sec

what happens now is that the sync occurs something like every 17 mins i believe this is the default

500pts if u help with this setup?

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Asked On
2009-07-30 at 16:17:34ID24614845
Tags

w32tm windows server 2003 2008 sync time ntp microsoft

Topics

Windows 2003 Server

,

Windows NT Networking

,

Windows Vista

Participating Experts
3
Points
500
Comments
17

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Answers

 

by: ecsrdPosted on 2009-07-30 at 16:22:28ID: 24985244

Why exactly would you want to generate that much network traffic?  Even if your clients were absolutely terrible at keeping time on their own, they wouldn't lose more than a few milliseconds in 17 minutes!

 

by: btassurePosted on 2009-07-30 at 16:27:51ID: 24985269

Try here:
http://www.djdingo.com/ntptutorial.html
if you can ignore the colour scheme it is quite useful, and a direct rip from the MS site I think but never mind.
Just set your poll interval to be in the low seconds, but be aware of any impact this may have on other things like your internet connection. Also aim for a stratum 2 server, there are more of them, they are less busy generally and they are ALMOST as accurate as a stratum 1 but you are never going to get that level of accuracy with what you are doing anyway. I would suggest a 15 second poll is overkill. Anything you are doing that requires THAT level of clock accuracy means you are probably using the wrong tools with a PC/NTP server. Your PC clock will be accurate to within a second every 15 by a LONG stretch. I would go with more like a 300 second interval at the LOWEST. The PCs in the domain will sync their time automatically.

Perform the same steps as in that link on the clients but change the variables to match your interval and tell it to point to the 2003 server for updates.

 

by: ChiefITPosted on 2009-08-01 at 11:12:38ID: 24996138

There are things  you should know before setting up time.

Your clients will automatically synchronize to your server, If it is out of a 5 minute phase offset. The phase offset means +/- 5 minutes out of synch. This is the default configuration of the time service.

Also, to synchronize to an outside time source, you could be blocked by some firewalls. The best way around this is to download a program called Symmtime. Symmtime was created by Symmetricom. They manufacture time servers. Symtimme, unlike the default time service, will go out on port 80 and synch to an outside time server. Port 80, is of course, the HTTP port. So, if you have internet, Symmtime is the easiest and best way to synch your PDCe to an outside time source. It is a free utility.

Once your PDCe is synched up, the default configuration of the PDCe set registry flags that lets the client know to come synch with it upon logon, or upon getting 5 minutes out of phase.

 

by: EmilenethPosted on 2009-08-11 at 15:09:19ID: 25073999

OK sorry for the delay experts Exchange had problems with the database

Well its not that every workstation is time critical but  I have 9 radio stations and 2 recording machines where there are legal implications if they are out of sync, by out of sync I mean more than 30 second offset . The computers are very bad at handling time

My current objective is +/- 30sec phase offset. Even at that rate my logs about commercial spots showing will not be accurate so I will improve it further

Seems like W32tm haves several documented but badly documented configurations here I will express only a few:
·         Source: http://technet.microsoft.com/en-us/library/cc773263(WS.10).aspx

AnnounceFlags
Registry path
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Config
Version
Windows XP, Windows Vista, Windows Server 2003, and Windows Server 2008
This entry controls whether this computer is marked as a reliable time server. A computer is not marked as reliable unless it is also marked as a time server. 0x00 Not a time server
0x01 Always time server
0x02 Automatic time server
0x04 Always reliable time server
0x08 Automatic reliable time server

The default value for domain members is 10. The default value for stand-alone clients and servers is 10.

Here for example what the hell is 10 ¿?¿?¿ in the registry defaults to 0x0a, but documentation shows us as decimal 10 for default,  my guess here is that its sum of 0x2 Automatic time server and 0x08 Automatic reliable time server resultin in 0x0a (10 dec)

FrequencyCorrectRate
Registry path
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Config
Version
Windows XP, Windows Vista, Windows Server 2003, and Windows Server 2008
This entry 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.
Note
0 is an invalid value for the FrequencyCorrectRate registry entry. On Windows Server 2003 and Windows Server 2008 computers, if the value is set to 0 the Windows Time service will automatically change it to 1.
 
In these case this value specifies a very useful stuff but its almost undocumented, the clock is corrected several times per minute using some internal algorithm
 
HoldPeriod
Registry path
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Config
Version
Windows XP, Windows Vista, Windows Server 2003, and Windows Server 2008

This entry 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.


Used in convination with the last one helps to setup the time at wich the system ignores spikes (described above) in that badly documented internal clocking algorithm


So pls dont send me to documentation, or at least not a that bad documentation from Microsoft that is my 1st problem

 

by: EmilenethPosted on 2009-08-11 at 15:18:04ID: 25074065

do u know how many bytes are used for a full sync?

i believe that the traffic is even less than dns queries as it just takes for some timestamps to be retreived and the internal algorithm does the rest

 

by: EmilenethPosted on 2009-08-11 at 15:19:16ID: 25074073

My ideal here is that this time critical workstations make a full-sync every minute and minor corrections every 2 seconds without the need for network traffic

 

by: EmilenethPosted on 2009-08-11 at 15:24:10ID: 25074109

My DC and workstations can perform full-sync at 5min (300 secs), if and only if, the internal statistical algorithm is very well configured :)

.org time servers allow a queries if they are separated every 4 secs, more than that will be considered as hammering

seems like i will check the RFC for NTP

 

by: EmilenethPosted on 2009-08-11 at 15:28:25ID: 25074127

Wikipedia says that the NTP packet is very short, something like 512 bytes, .org statum 2 servers are not affraid to send a packet every 4 secons

 

by: EmilenethPosted on 2009-08-11 at 17:00:07ID: 25074690

In the case of:

NtpServer
Registry path
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Parameters

Version
Windows Server 2003 and Windows Server 2008

This entry 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. Each DNS name or IP address listed must be unique. Computers connected to a domain must synchronize with a more reliable time source, such as the official U.S. time clock.

0x01 SpecialInterval


0x02 UseAsFallbackOnly


0x04 SymmatricActive


0x08 Client


There is no default value for this registry entry on domain members. The default value on stand-alone clients and servers is time.windows.com,0x1.

Can u explain whats the meaning of those values?

I know 0x01 SpecialInterval is for setting an initial poll interval but its is dynamicaly adjusted by the internal algorithm and the key

PollAdjustFactor Registry path
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Config

But again this other key is very dark in the way it works

 

by: ChiefITPosted on 2009-08-12 at 07:57:09ID: 25079374

In your case, where time is of the essence, you might consider a time server with a bit of software that can keep you within a nat's arse of synchronization.

I work on a research ship. We use GPS and synch that up to data being collected on the ocean floor. In other words, all of my sensor data as well as my multibeam data uses the time stamp to synchronize to the exact time, (within milliseconds). You can see what I do in my profile.

I use GPS time servers, and you can use Atomic time servers.

______________________________
The typical way time is set up is if your client's are +/- 5 minutes out of the "phase offset" of your PDCe, it will synchronize. This means your client's and member servers can be 4m59s off before it synchronizes. For your application, this is unacceptable. The standard configuration uses the synchronization flags. Within the data, you will see the phase offset. The synchronization flags tell computers on the network "I AM THE TIME SERVER". By default, that is your PDCe. The phase offset say, "YOU HAVE TO BE WITHIN 5 MINUTES OF ME, OR YOU MUST SYNCH UP". For your application, that is unaccptable.

So, the standard configuration of your time is inadequate.
_________________________________________________________________________

Let's look at alternatives.

Option 1) Time is broadcasted, you can change your phase offset to a much lower offset than 5 minutes. That means you will be lowering the tolerances from +/- 5 minutes to your manually defined settings. I don't know what the phase offset can be. I think it can be in seconds.

You can see all of the time synchronization flags on these articles. They are registry settings that it looks like you already found. Please note, these articles tell you how to set up an authoritative time server. By default, this is how time is synchronized anyway>

So, option 1 is manually adjusting the phase offset:
http://support.microsoft.com/kb/216734 (2000 domain controller)
http://support.microsoft.com/kb/816042 (2003 domain controller)


Option 2)
Symmtime is a free utility that you can manually configure to synchronize to an outside time server whenever you want. Symmtime was created by Symmetricom, (a time server manufacturer). It goes out on port 80 and 123 tol synch to an outside time server of your choosing or your internal time server. There is a long list of time servers to choose from, OR you can configure it to pick up time from your time server or atomic clock that spits out time.
Free Utility:
Symtime: http://www.ntp-systems.com/software_download.asp?ID=product_software_lmcheck.asp

I use symmtime on all clients and servers to contact my symmentricom GPS time server and atomic clocks. Remember time is as imporant to my data synchronization as it is yours. When my clients are collecting data, they use POSMV time synchronization pulses every second.

Right now, your biggest problem is you installed a NTP time server and don't know how to synch with it. That's because, by default, your domain computers synch to the domain controller. SYMMTIME is your answer to this problem. Install it on all computers. It's easy to configure!

Then, as a check, Symmetricom has another free tool called LMcheck. LM
http://www.symmetricom.com/resources/downloads/lmcheck-software/
____________________________________________________________________________
Option 3)
Symmetricom also has another Paid utility. It is called "Domain Time II". With this software, you have full control of your entire domain's time even over complex networks.

""Domain Time II is a network time synchronization software is an essential part of distributing time to synchronize the network. Symmetricoms Domain Time II is a comprehensive network time synchronization software suite that simplifies and monitors network time synchronization on servers and clients. It is 100% compatible with all NTP servers.""

http://www.symmetricom.com/resources/downloads/domain-time-ii-software/?search=domain%20time%20II
___________________________________________________________________
Option 4)
You could get in contact with the manufacturer of your time server. They may have better solutions that these.

My application requires that my time be within milliseconds, or my oceanographic data will be corrupt. You can see what I administer by looking at my EE biography.

Option 4 is basically looking at other options through your time server manufacturer's point of view. Symmetricom has a list of things they recommend for broadcasted media. Here is the web page of options they recommend:

http://www.symmetricom.com/industry-solutions/broadcast-infrastructure/

____________________________________
My personal opinion:
If you are willing to spend a few $$, go with Domain Time II. Otherwise, download symmtime to a client machine and play with it a little. When you figure that out and like it, you can download it on the PDCe, as well as LMcheck to monitor the domain's time. I think that will suit your purpose.


 

by: EmilenethPosted on 2009-08-12 at 19:03:38ID: 25085034

Oks im checking out the current non option, as there will be hardly good documentation on MS service

 

by: EmilenethPosted on 2009-08-12 at 19:04:28ID: 25085039

Oks im checking out the current non microsoft option, as there will be hardly any good documentation on the w32tm service

 

by: ChiefITPosted on 2009-08-12 at 21:22:55ID: 25085419

You could use a combination of both MS default option and symmtime.

Remember, by default clients within a domain will synch to your PDCe. So you can install symmtime on the PDCe and then, set it up to synchronize every minute with your NTP time server.

Once done, then go in and change the phase offset to be 3 seconds. Those registry keys are in the microsoft documentation.

It really depends on how accurate you want time to be. If a couple seconds difference is good enough, download symmtime on the PDCe and then set your phase offset to be a couple seconds difference.

 

by: EmilenethPosted on 2009-08-14 at 17:02:27ID: 25103315

I've checked up the sysmmetricom option but the free utility is for desktop enviroments in my case cant use it as the free util proposes.

Finaly ive came with a configuration of w32tm.

-------------------------------------------
Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time]
"Start"=dword:00000002

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Config]
"FrequencyCorrectRate"=dword:00000002
"PollAdjustFactor"=dword:00000005
"LargePhaseOffset"=dword:02faf080
"SpikeWatchPeriod"=dword:00000384
"LocalClockDispersion"=dword:0000000a
"HoldPeriod"=dword:00000005
"PhaseCorrectRate"=dword:00000001
"UpdateInterval"=dword:00000064
"EventLogFlags"=dword:00000002
"AnnounceFlags"=dword:00000000
"MinPollInterval"=dword:00000002
"MaxPollInterval"=dword:00000004
"MaxNegPhaseCorrection"=dword:ffffffff
"MaxPosPhaseCorrection"=dword:ffffffff
"MaxAllowedPhaseOffset"=dword:00000001

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Parameters]
"Type"="NTP"
"NtpServer"="hsrv-b.leon.radioramabajio.net,0x8"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpClient]
"Enabled"=dword:00000001
"InputProvider"=dword:00000001
"AllowNonstandardModeCombinations"=dword:00000001
"CrossSiteSyncFlags"=dword:00000002
"ResolvePeerBackoffMinutes"=dword:00000001
"ResolvePeerBackoffMaxTimes"=dword:00000007
"CompatibilityFlags"=dword:80000000
"EventLogFlags"=dword:00000001
"LargeSampleSkew"=dword:00000003
"SpecialPollInterval"=dword:00000004

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpServer]
"Enabled"=dword:00000000
"InputProvider"=dword:00000000
 ------------------------------------------------

 

by: EmilenethPosted on 2009-08-14 at 17:45:38ID: 25103417

Last config was for the critical workstations

For the 2003/2008 NTP server:
---------------------------------------------
Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time]
"Start"=dword:00000002

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Config]
"FrequencyCorrectRate"=dword:00000002
"PollAdjustFactor"=dword:00000005
"LargePhaseOffset"=dword:02faf080
"SpikeWatchPeriod"=dword:00000384
"LocalClockDispersion"=dword:0000000a
"HoldPeriod"=dword:00000005
"PhaseCorrectRate"=dword:00000001
"UpdateInterval"=dword:00000064
"EventLogFlags"=dword:00000002
"AnnounceFlags"=dword:00000000
"MinPollInterval"=dword:00000002
"MaxPollInterval"=dword:00000004
"MaxNegPhaseCorrection"=dword:ffffffff
"MaxPosPhaseCorrection"=dword:ffffffff
"MaxAllowedPhaseOffset"=dword:00000001

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Parameters]
"Type"="NTP"
"NtpServer"="hsrv-b.leon.radioramabajio.net,0x8"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpClient]
"Enabled"=dword:00000001
"InputProvider"=dword:00000001
"AllowNonstandardModeCombinations"=dword:00000001
"CrossSiteSyncFlags"=dword:00000002
"ResolvePeerBackoffMinutes"=dword:00000001
"ResolvePeerBackoffMaxTimes"=dword:00000007
"CompatibilityFlags"=dword:80000000
"EventLogFlags"=dword:00000001
"LargeSampleSkew"=dword:00000003
"SpecialPollInterval"=dword:00000004

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpServer]
"Enabled"=dword:00000000
"InputProvider"=dword:00000000
-----------------------------------------------------

 

by: EmilenethPosted on 2009-08-14 at 17:48:08ID: 31616046

I still have some questions about the configs but maybe later ill post em

 

by: ChiefITPosted on 2009-08-16 at 00:02:32ID: 25108048

I use symmtime on both my 2003 and 2008 servers in 14 sites. They work perfectly for that.

20120131-EE-VQP-002

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