[ntp:questions] Any samples for NTP/SNTP client code?

guuwwe at hotmail.com guuwwe at hotmail.com
Sat Dec 1 21:13:00 UTC 2007


On Dec 1, 3:07 pm, Joseph Gwinn <joegw... at comcast.net> wrote:
> In article
> <90967f07-83ca-4d79-8acb-1c3056ce3... at l1g2000hsa.googlegroups.com>,
>
>  guu... at hotmail.com wrote:
> > Does anybody know of any *practical* samples on how to
> > implement NTP/SNTP client?. The goal is to provide accurate
> > time for a program/client running on Windows Vista.
>
> > Specifically, what values to include in the the request message,
> > how to process the reply message, etc.
>
> > I am NOT asking how to send/receive UDP datagrams, or where
> > to find comprehensive descriptions like RFC documents, or how
> > to build or design user interfaces.
>
> > Only a narrow description focused on NTP/SNTP request/reply
> > datagrams for a simple PC client, preferably in C/C++ source
> > code.
>
> I've done this in an embedded realtime system.  (No, the source code is
> not available.)  
>
> In Appendix A of RFC-1305 you will find the format of the NTPv3
> request/response packet.  Send this packet to port 123 of the NTP
> server, and read the reply packet.  It's pretty easy.  
>

 I saw this format. From data comm point of view it is very unusual
 to have the same format for request and reply.

 Sending/receiving the packet to port 123 is the first thing I tried.
 This is not an issue. The issue is to use all the  values in
 request and reply correctly and reliably. And the quickest
 way is to get as many ***samples*** as possible, the
 RFC  doc ***alone*** is the slowest way.





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