[ntp:questions] Re: Questions and ruminations regarding NTPD 4 config and XP's bad behavior.

David L. Mills mills at udel.edu
Sat Jan 15 02:46:34 UTC 2005


XP is normally configured not to operate as a server, as I just now mave 
confirmed. If so, they violate not only the NTP protocol (using 
symmetric rather than client mode) but violate the SNTP prohibition not 
to opeate as a server unless directly synchronized to a broadcast or 
modem source.

A server with nominal frequency error of 100 PPM will be in error 8.64 
seconds after one day and one minute after one week. The same thing 
holds for ntpdate. If the error expectations are less than a minute or 
so, not to worry. However, clock errors over such periods are dominated 
by random-walk phenomena, so there is a chance, althoug a small one, 
that a chain of servers like that can accumulate errors of many minutes 
at the end of the chains.


elickd at one.net wrote:

> I don't want them to serve time at all.  They're workstations that are
> set to query time once a week, but are answering because Microsoft
> apparently can't be bothered to read RFCs.
> I want the NTP servers I spoke of to ignore these machines so in the
> off chance of NTP instability in our stratum hierarchy, there's no way
> they can provide bogus time.
> Something in our timeserver network is glitchy enough to cause my SCO
> boxes (and there are thousands of them) to pick up bogus time at random
> intervals.
> Doug

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