Slow clocks in mainland Europe - how much of a problem is it really?

[Rob Morley]

Someone may have already posted this but just in case ... If you can't find pointy clicky configuration items in Linux look in /etc for something that looks relevant, in this case /etc/ntp.conf then do "man ntp.conf" to find:

minpoll minpoll, maxpoll maxpoll These options specify the minimum and maximum poll intervals for NTP messages, in seconds as a power of two. The maximum poll interval defaults to 10 (1,024 s), but can be increased by the maxpoll option to an upper limit of 17 (36.4 h). The minimum poll interval defaults to 6 (64 s), but can be decreased by the minpoll option to a lower limit of

4 (16 s). These option are valid only with the server and peer commands.

[Roger Hayter]

AIUI, ntp works best when making its own decisions about how often to poll servers. It bases its decisions on the time stability it achieves which depends on local factors and the quality of the servers it is using. There used to be an alternative, ntpdate or something, which could be run by cron at user chosen intervals, I think this is now part of ntp but can be used if desired. The best solution to maintaining optimum time stability without excessively burdening public servers is to use ntp, but only allow one machine on the network to contact external servers and sync other machines to it. I.e. use ntp on the other machines but direct it to use only the local server.

The other way to reduce the burden on publicly-funded time servers is to use some ot the voluntarily supplied ntp servers:

and I think Linux often does, but Microsoft and Apple don't, perhaps for political reasons. This pool is probably not good enough for people really keen on optimum time precision, but quite good enough for most of us.