[ntp:questions] simple nt.conf cases for ntp-client

William Unruh unruh at invalid.ca
Thu Jan 23 18:11:52 UTC 2014

On 2014-01-23, ardi <peter.knezel at gmail.com> wrote:
> On Thursday, January 23, 2014 9:36:35 AM UTC+1, Marco Marongiu wrote:

a) Please stop using Google for your mail server. They insert blank
lines between every setnece you quote including blank lines which means
they rapidly make your posts completely unreadable. 

b) Unless that server xx.xx.xx.xx is under your own personal control,
using minpoll 4 maxpoll 4 is very rude, since it tends to overload
someone else's computer. The default is minpoll 6 maxpoll 10 which are
usually more than enough. 

> Does it mean these minpoll, maxpoll parameters are not needed in most of the cases?


> According to book Expert
> Network Time Protocol from PETER RYBACZYK:
> "The minpoll and maxpoll parameters represent minimum and maximum polling intervals for reference clock messages in seconds to the power of 2. For example, if minpoll=3 and maxpoll=4, the minimum polling interval would be 8 seconds, and the maximum polling interval would be 16 seconds."
> What does "minimum and maximum polling intervals for reference clock messages"
> mean? 
> polling = messaging with NTP servers to estimate the offset ???

If the source is a refclock, and minpoll 4 maxpoll 4 make sense. It is
also under your own personal control ( connected directly to your
computer). That would mean that it got the time from the refclock every
16 seconds. 

>> First: don't use two servers, it's the worst possible configuration.
> Why not? what if one of the servers fail? then the client can get time from the other ntp-server.

And how does it know that one of the servers has failed. And which one
it is that has failed? Failure usually does not mean tht the server
delivers no time at all, it just delivers the wrong time. 

> Doesn't the real setup consist of 
> some stratum 1 time servers, then at least two stratum 2 ntp servers
> which are in peer with each other (and takin time form one or more stratum 1 time servers) and clients are taking time from these
> stratum 2 servers?

No. that is not the "real setup". It is a possible one amongst an
infinitude of other possibilities. 

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