On 2021-06-25, Jim Pennino <[email protected]> wrote: > William Unruh <[email protected]> wrote: >> On 2021-06-25, Jim Pennino <[email protected]> wrote: >>> chris <[email protected]> wrote: >>>> On 06/25/21 04:08, Jim Pennino wrote: >>>>> William Unruh<[email protected]> wrote: >>>>> >>>>> <snip old stuff> >>>>> >>>>>> I suspect it is the number of times that ntpd tries to contact the >>>>>> server and fails rather than the time that is important. You could try >>>>>> putting the server offline and then online again (I use chrony so do not >>>>>> remember if ntpd has that option). >>>>> >>>>> No, it doesn't. >>>>> >>>> >>>> You could use a one line cron script to restart every day, week, >>>> whenever... >>> >>> Or for $14/machine I could use a USB GPS, my machine with PPS GPS, and a >>> public server that does not request use of DNS. >> >> You could try specifying the server by IP rather than by name, so DNS is >> not needed. Of course this rule out using pool, unless you put them in >> by IP. DNS is just used to translate names to IP, so if you use IP, then >> DNS is not needed. > > > Or for $14/machine I could use a USB GPS, my machine with PPS GPS, and A > public server that does NOT request use of DNS which yields 3 sources of > time without using a pool or DNS lookups.
Not at all sure what you are suggesting. DNS is a way of translating names to IP addresses, which your machine MUST use to talk to a remote machine not on your network. The remote machine has nothing to do with this. Now some remote machines will as for the name associated with the IP address of machines sending the remote machine a query, to try to see if someone is spoofing the IP address, but as far as I know ntpd does not do that. Takes too much time and would make the time responses really bad. > > Or for $28/machine I could use 2 USB GPS receivers and my machine with > PPS GPS, which also provides 3 sources of time without any network >e access at all. Sure. The problem of course is that that $28 onlybuys you a pretty bad time source (pretty bad meaning milliseconds rather than microseconds or nanoseconds), which for most of man's history on this earth is absolutely astonishingly, and inconceivably good. Note that hanging all three off of one machine can lead to conflict between them as to interrupt processing, leading to degraded time performance. But again that is at the microsecond level, not milli or second level. Of course if you machine is at the bottom of a mineshaft in mountains, gps receivers are pretty useless. Or in the basement of a highrise without windows. > > _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
