Re: simple time server - NTP

This is a discussion on Re: simple time server - NTP ; >If you are willing to settle for time to the nearest second you can use >rdate. If you need better; e.g. time to the nearest 100 milliseconds or >better, SNTP *might* do it for you but I wouldn't want to ...

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Thread: Re: simple time server

  1. Re: simple time server

    >If you are willing to settle for time to the nearest second you can use
    >rdate. If you need better; e.g. time to the nearest 100 milliseconds or
    >better, SNTP *might* do it for you but I wouldn't want to rely on it myself.


    SNTP looks, from reading the introduction in the spec, like what I
    want because it's provides rdate-like service, but using essentially
    NTP (which I like because it's so common) and subsecond precision.
    But I would still need an SNTP server program unlike what's available
    today, whereas an adequate rdate ("time" protocol) server already
    exists. So I'll have to weigh my options -- thanks for providing
    them!

    >You can, if you wish, use ntpdate to set your clocks from some NTP
    >server. You could run it in a cron job once an hour or something like
    >that and it should keep your clock within a hundred milliseconds of the
    >server unless you have a machine with a really bad local clock.


    For my computers on the Internet, I have been doing something like
    this, but much less, for many years and have been quite happy with it.
    My cron job runs Ntpdate once a _week_ and I monitor the amount of
    correction it has to make. When the system clock is properly
    calibrated, it's about 50 milliseconds each week. On a few of the
    computers, the clock speed changes so that a couple of times a year
    the correction grows beyond 250 milliseconds, and I manually change
    the clock speed (Linux adjtimex) to get back to the 50 ms/week. Note
    that for corrections less than 500 ms, Ntpdate slews the correction
    in.

    For what these computers do, this is more than enough precision and I
    appreciate the simplicity and flexibility of it compared to the
    conventional NTP deployment (simplicity and flexibility usually mean
    less maintenance work for me and fewer disasters).

    [By contrast, what I'm asking about now has to do with the computers
    that are not on the Internet; it would be nice if I could use the
    exact same strategy on them, except point them to a simple NTP server
    (on one of my computers) that serves the local system clock time.]

    >Ntpdate does not provide the full functionality of ntpd and it is
    >"deprecated" and sooner or later will be dropped from the
    >distribution.


    Not a problem, since I already have my copy, and the program probably
    won't need any maintenance.

    --
    Bryan Henderson Phone 408-621-2000
    San Jose, California
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    questions mailing list
    questions@lists.ntp.isc.org
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  2. Re: simple time server

    An NTP server is also an SNTP server, if this helps.

    H

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