[ntp:questions] Beginner needs help...

Robert Hegner robert.hegner at hsr.ch
Wed Mar 2 12:01:20 UTC 2011


Am 02.03.2011 10:05, schrieb Dave Hart:
> On Tue, Mar 1, 2011 at 07:10 UTC, Robert Hegner<robert.hegner at hsr.ch>  wrote:
>> Thanks Chris and Dave for your answers.
>>
>> I think I should give some more information about the computer I want to use
>> as time server. This computer has two network interfaces. One is for the
>> mentionned local network and using the other one it is connected to the
>> company network and internet.
>>
>> My first attempt was to synchronize this computer to a set of public time
>> servers. This didn't work because this system synchronizes its time with the
>> domain, and domain policies do not allow the NTP service to set the time.
>> This is why I changed the config file of 192.168.0.1 to use the local clock
>> (and therefore the domain time) as reference. Isn't this the same situation
>> as if I used a radio clock as a reference on this system?
> It sounds like you think 192.168.0.1's clock is being controlled by
> the domain, but it's not if you're running ntpd as you described.  The
> Meinberg installer disables the W32Time (Windows Time) service which
> is the agent that keeps your clock in sync with the domain.  W32Time
> and ntpd can't coexist on a single machine, as they both use the NTP
> protocol and listen on UDP port 123.
>
You're right, W32Time was disabled on 192.168.0.1. I uninstalled 
Meinberg NTP on this machine and now W32Time is running again.
>> So since I want the same time on all three computers and since I cannot
>> modify the clock of 192.168.0.1, it was the obvious solution for me to use
>> that computer as the (single) time server in my setup.
> You may not have permission to modify the clock, in which case you
> might uninstall NTP and re-enable the Windows Time service, and your
> other two machines will sync to Windows Time.  You'll probably need
> "tos maxdist 20" or so in the ntp.conf of machines pointed to a
> W32time source, as W32time polls upstream sources very infrequently,
> perhaps once a day in a domain setup (and once a week otherwise).
>
Can W32time act as a server for the Meinberg NTP version on my other 
computers? Is there a special configuration needed for this to work? 
With my unmodified config files on 192.168.0.2 and 192.168.0.3, these 
computers don't reach a time server on 192.168.0.1.
>> Would my setup work better if only I used WinXP on 192.168.0.1, or is using
>> the domain time as a reference a bad idea anyway? (I don't know what
>> mechanism is used to synchronize my computer to the domain time, and I don't
>> know what the reference for the domain time is...).
> How tight is your synchronization requirement among these three
> machines?  That makes a big difference in which solutions will work.
>
I could live with +-10ms. But less would be better...

> Cheers,
> Dave Hart




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