[ntp:questions] Re: This is tougher than I thought?

David J Taylor david-taylor at blueyonder.co.not-this-bit.nor-this-part.uk.invalid
Sat Jan 21 10:54:29 UTC 2006


Axonn wrote:
[]
> So how can I synchronize with a NTP server or more NTP servers? Is it
> so hard as I imagine after going a little through the FAQs? I would
> hope that the hard part is for servers, not for clients. I await your
> answers with great anticipation.
>
> Thank you very much for your time,
> Axonn Echysttas,
> ASD Clock creator.

Axonn,

I have two answers for you:

1 - NTP is already available for Windows.  You can download client 
software here:

  http://www.meinberg.de/english/sw/ntp.htm

Then use the normal Windows functions to read the system time, and let NTP 
worry about setting the system time.  By the way, this client also 
incorporates the server.  My understanding is that the client is the 
harder part, at least the precision timekeeping part, and deciding which 
server to trust.

2 - to get a simple time value, use the SNTP protocol.  See:

  http://www.faqs.org/rfcs/rfc2030.html

Basically, format a packet as shown in section 4, send it to the chosen 
NTP server over UDP on port 123, and parse the packet you get back.  For 
greatest simplicity, use the "Transmit" timestamp field, but you can do 
better.

By far the best way is to let the NTP software (1) control the computer's 
clock.

Cheers,
David 





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