[ntp:questions] Re: Question about RFC-2030 SNTP Version4

David J Taylor david-taylor at blueyonder.co.uk
Fri Aug 1 19:44:37 UTC 2003


> No matter what Values I plug in for T1,T2,T3 & T4, they
> don't come out to the expect values.

Sorry, I was wrong.  You better check the RFCs.

As I now read it, in the packet T1 is completed by the server as the
reference time.
T2 is what the client filled in when it sent the packet, and T3 and T4 are
completed by the server on receipt of the client packet, and sending of
the return packet.

On your client, you should note the time at which the packet is sent (TA),
and the time at which the reply is received (TB).  The client could use T2
to check that the packet it got back was in response to its own request
(i.e. T2 = TA), and it could use T1 for server sanity checks.  It is
actually T3, T4, TA and TB that are used in the delay and offset
calculations.

I hope this is now correct!

Cheers,
David





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