[ntp:questions] Problem with system clock refresh

Martin Burnicki martin.burnicki at meinberg.de
Thu Nov 26 10:42:54 UTC 2009


David J Taylor wrote:
> "JuanFran" <juanfranciscojara at gmail.com> wrote in message
> news:d693971e-be41-4a9b-9926-ed4a04f5b319 at j9g2000vbp.googlegroups.com...
>> Good mornig. I have a trouble with NTP. I want a refresh my sistem
>> clock (client) with a LAN Server each 5 minutes. I don?t know any
>> parameter of NTP protocol for this configuration. It?s possible? The
>> refresh it done usually, but takes a long time.
>> I use Windows XP with meinberg software (client and server monitor).
>> Thank you!
>> PD: sorry for my poor english! :-)
> Why do you want to do this, Juan?  NTP will automatically adjust the
> interval between contacts to the server according to its own needs, and
> you don't normally need to set this.  If you /really/ need to do this, you
> could edit the ntp.conf file with notepad to have entries similar to this:
> _____________________________________________
> server    <lan-address>    maxpoll 8    iburst
> server    <internet-address>    minpoll 10
> server    <internet-address>    minpoll 10
> server    <internet-address>    minpoll 10
> server    <internet-address>    minpoll 10
> _____________________________________________
> This sets the LAN-server to poll not less than once every 256 (2^^8)
> seconds, and have backup Internet servers which are polled at not less
> than 1024 (2^^10) second intervals.

>From the original question I'd understand that Juan expected the system time
to be *set* once after each poll in 5 minute intervals. Of course ntpd
doesn't work this way, but if you force the minpoll value higher this lets
ntpd synchronize even slower than it normally does. I'd suggest to omit the
minpoll keywords and just use one or several entries like

server <address> iburst

Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont

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