Re: NTP.conf pool vs server

From	Darac Marjal <mailinglist@darac.org.uk>
Newsgroups	linux.debian.user
Subject	Re: NTP.conf pool vs server
Date	2017-06-07 17:00 +0200
Message-ID	<tPKBf-7Z0-79@gated-at.bofh.it> (permalink)
References	<tPJ2q-77i-15@gated-at.bofh.it> <tPKhP-7Rr-5@gated-at.bofh.it>
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On Wed, Jun 07, 2017 at 10:35:23AM -0400, Gene Heskett wrote:
>On Wednesday 07 June 2017 08:56:59 ray wrote:
>
>> I would like to know the correct syntax for entering a server entry
>> for stretch.
>>
>> All the documentation I find says to list the ntp servers in the file
>> as: server 0.XX.pool.ntp.org
>> server 1.XX.pool.ntp.org
>>
>> An example source from 2017 is https://wiki.debian.org/DateTime
>>
>> When I open /etc/ntp.conf on my new stretch installation, I find this
>> format: pool 0.debian.pool.ntp.org iburst
>> pool 1.debian.pool.ntp.org iburst
>>
>> The latest Debian doc says to start the line with 'server'.
>> The latest Debian implementation starts the line with 'pool'.
>>
>> Are these interchangeable?

As I understand it "server" will do name resolution once and pick an IP
from the result. "pool" will periodically refresh the name and cycle to
a different member of the pool.

>>
>> Additionally, there is a parameter 'iburst' which I did not find in
>> the Debian docs but found at http://doc.ntp.org/4.1.1/confopt.htm

Did you install ntp-doc? Did you check there?

>>
>>
>> Thanks,
>> Ray
>
>Begin rant:
>
>From someone who is currently battling a fresh jessie install that didn't
>even come with ntpdate installed, and which using the above format
>in /etc/ntp.conf is still about 12 hours off on an rpi-3.
>
>Installing ntpdate and attempting to start it gets me a no servers found
>message, yet they are defined as discussed above, and the network is
>fully accessible to all other forms of communication.
>
>That doc on www.ntp.org is nice, but worthless to someone who just wants
>it to work. I have quite a zoo of machines here, and I see little
>advantage to each one banging on a network server, when it needs an
>update.  But does it give even a hint of how to make this machine, or
>heaven forbid, my router, which keeps time via ntp, and which I believe
>has the time broadcast enabled, (its dd-wrt in a buffalo box) into a
>server that the rest of my machines can listen to to get the correct
>time. If I could achieve that, it would reduce the loading on the time
>servers at debian or pool.ntp.org by a factor of 5 or 6 just from my
>home network.

By a factor of 5 or 6? You think you own 5 or 6 times more servers than
everyone else combined? (I think you just mean "reduce [...] by 5 or
6").

Does your router inform other devices on the network that it should be
used as a time server? In the DHCP specification there is an option
called "time-servers". The idea is that a network administrator sets
this to be the approved time servers for the network and clients
synchronise to that. In debian, this is facilitated by
/etc/dchp/dhclient-exit-hooks.d/ntp (at least, if you use the ISC DHCP
client). That script will read the "time-servers" option from the DHCP
packet, write /var/lib/ntp/ntp.conf.dhcp and ensure that file is
included from your main ntp.conf. As far as I'm aware, this is default
behaviour.

>
>But a manpage that actually tells us how to do that must be sick bird,
>because its not been written yet.  Man page writers please get real, and
>tell us how to do something like getting our home networks all
>synchronized to our routers which can then broadcast it to the rest of
>our network.

There's an XY problem here. You probably shouldn't put this information
into the NTP man pages, as it's not NTP that's doing the work. The
information about the "time-servers" option *is* in the DHCP manpage,
but probably there's no information about the specific hook being
included.

If the NTP hook is Debian-specific, then... I don't know where that
should be documented. If it's upstream, then... Well, if every project
documented every decision for creating every file, then there'd be a lot
to wade through.

>
>Such a scheme can easily keep us on time with any errors within a few
>milliseconds, more than adequate enough for the girls I go with. While
>reducing the load on the servers by at least 80%.
>
>So how about a manpage that tells us how to do that?  If its not illegal
>according to some rfc that is.
>
>Rant off.
>
>Thanks for reading.
>
>Cheers, Gene Heskett
>-- 
>"There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
>-Ed Howdershelt (Author)
>Genes Web page <http://geneslinuxbox.net:6309/gene>
>

-- 
For more information, please reread.

Thread

NTP.conf   pool vs server ray <ray@aarden.us> - 2017-06-07 15:20 +0200
  Re: NTP.conf   pool vs server Greg Wooledge <wooledg@eeg.ccf.org> - 2017-06-07 15:30 +0200
    Re: NTP.conf   pool vs server Gene Heskett <gheskett@shentel.net> - 2017-06-07 16:50 +0200
  Re: NTP.conf   pool vs server Gene Heskett <gheskett@shentel.net> - 2017-06-07 16:40 +0200
    Re: NTP.conf   pool vs server Greg Wooledge <wooledg@eeg.ccf.org> - 2017-06-07 17:00 +0200
    Re: NTP.conf   pool vs server Darac Marjal <mailinglist@darac.org.uk> - 2017-06-07 17:00 +0200
      Re: NTP.conf   pool vs server Greg Wooledge <wooledg@eeg.ccf.org> - 2017-06-07 17:10 +0200
        Re: NTP.conf pool vs server Joshua Schaeffer <jschaeffer0922@gmail.com> - 2017-06-07 17:30 +0200
          Re: NTP.conf pool vs server Greg Wooledge <wooledg@eeg.ccf.org> - 2017-06-07 17:50 +0200
        Re: NTP.conf   pool vs server Henrique de Moraes Holschuh <hmh@debian.org> - 2017-06-07 18:10 +0200
      Re: NTP.conf   pool vs server Darac Marjal <mailinglist@darac.org.uk> - 2017-06-07 17:20 +0200
      Re: NTP.conf   pool vs server Gene Heskett <gheskett@shentel.net> - 2017-06-08 01:10 +0200
        Re: NTP.conf   pool vs server Darac Marjal <mailinglist@darac.org.uk> - 2017-06-08 14:30 +0200
          Re: https_port "Adiel Plasencia Herrera" <adielp@estereocentro.icrt.cu> - 2017-06-08 14:50 +0200
            Re: https_port Darac Marjal <mailinglist@darac.org.uk> - 2017-06-08 15:30 +0200
              Re: https_port Henrique de Moraes Holschuh <hmh@debian.org> - 2017-06-08 17:00 +0200
                Re: https_port "Adiel Plasencia Herrera" <adielp@estereocentro.icrt.cu> - 2017-06-08 17:20 +0200
                Re: https_port Darac Marjal <mailinglist@darac.org.uk> - 2017-06-08 17:30 +0200
                Re: https_port Greg Wooledge <wooledg@eeg.ccf.org> - 2017-06-08 17:40 +0200
                Re: https_port Darac Marjal <mailinglist@darac.org.uk> - 2017-06-08 17:50 +0200
                Re: https_port "Adiel Plasencia Herrera" <adielp@estereocentro.icrt.cu> - 2017-06-08 18:00 +0200
                Re: https_port Jim Ohlstein <jim@mailman-hosting.com> - 2017-06-08 19:10 +0200
                Re: https_port Charlie Kravetz <cjk@teamcharliesangels.com> - 2017-06-09 16:40 +0200
                Reply-to-all or reply-to-list again (was: https_port) Nicolas George <george@nsup.org> - 2017-06-09 16:50 +0200
                Re: Reply-to-all or reply-to-list again (was: https_port) Fungi4All <fungilife@protonmail.com> - 2017-06-09 17:20 +0200
                Re: Reply-to-all or reply-to-list again The Wanderer <wanderer@fastmail.fm> - 2017-06-09 17:20 +0200
                Re: Reply-to-all or reply-to-list again Nicolas George <george@nsup.org> - 2017-06-09 18:00 +0200
                Re: Reply-to-all or reply-to-list again The Wanderer <wanderer@fastmail.fm> - 2017-06-09 21:20 +0200
                Re: Reply-to-all or reply-to-list again Joel Rees <joel.rees@gmail.com> - 2017-06-10 04:20 +0200
                Re: Reply-to-all or reply-to-list again Fungi4All <fungilife@protonmail.com> - 2017-06-10 16:00 +0200
                Re: Reply-to-all or reply-to-list again Joel Rees <joel.rees@gmail.com> - 2017-06-10 16:30 +0200
                Re: Reply-to-all or reply-to-list again Fungi4All <fungilife@protonmail.com> - 2017-06-10 18:00 +0200
                Re: Reply-to-all or reply-to-list again (was: https_port) Gene Heskett <gheskett@shentel.net> - 2017-06-09 17:30 +0200
          Re: NTP.conf   pool vs server Gene Heskett <gheskett@shentel.net> - 2017-06-08 16:10 +0200
    Re: NTP.conf   pool vs server John Hasler <jhasler@newsguy.com> - 2017-06-07 18:10 +0200
      Re: NTP.conf   pool vs server Brian <ad44@cityscape.co.uk> - 2017-06-07 18:30 +0200
        Re: NTP.conf   pool vs server David Wright <deblis@lionunicorn.co.uk> - 2017-06-11 18:00 +0200
          Re: NTP.conf   pool vs server Brian <ad44@cityscape.co.uk> - 2017-06-11 19:30 +0200
      Re: NTP.conf   pool vs server Teemu Likonen <tlikonen@iki.fi> - 2017-06-08 08:40 +0200
        Re: NTP.conf   pool vs server Curt <curty@free.fr> - 2017-06-08 09:20 +0200
        Re: NTP.conf   pool vs server Gene Heskett <gheskett@shentel.net> - 2017-06-08 15:40 +0200
    Re: NTP.conf   pool vs server Jim Ohlstein <jim@mailman-hosting.com> - 2017-06-07 18:40 +0200
  Re: NTP.conf   pool vs server Kushal Kumaran <kushal@locationd.net> - 2017-06-07 17:00 +0200

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