[AusNOG] A lot of AU NTP Servers appear to be misconfigured, and it's mildly annoying me.

Rob Thomas xrobau at gmail.com
Mon Aug 26 14:12:52 EST 2019


I would like to point out that Glen Turner discovered my ... uh,
deliberate mistake.  I meant, of course, that you use the PPS driver
(22) for PPS, and the SHM driver (28) for GPS, and you don't use the
NMEA driver (20) at all, unless reasons.

I have mentioned that I owe Glen a beverage of their choice next time
we are in beverage-providing proximity.

--Rob

On Sun, 25 Aug 2019 at 18:54, Rob Thomas <xrobau at gmail.com> wrote:
>
> I was rebuilding my local network over the weekend, and as part of
> that I had to relocate and reconfigure my Stratum 1 NTP server. As I
> was fine turning it, I discovered a significant number of Au NTP
> servers are misconfigured, and I thought I'd post a few quick tips
> here, for anyone providing a timing source, and using a GPS signal as
> Stratum 0.
>
> 1. If you're not using PPS triggers, PLEASE DON'T MARK YOURSELF AS A
> STRATUM 1 SERVER! Put this in your /etc/ntpd.conf:
>
> server 127.127.28.0 minpoll 4 maxpoll 4 stratum 2
> fudge 127.127.28.0 time1 0.135 refid GPS
>
> (Obviously adjusting your time1 amount to match whatever the delay of
> your GPS chip is)
>
> 2. If you ARE using PPS triggers, make sure that is flagged 'prefer'.
> This means that when you run `ntpq -n -p` you will have a * by 28.2
> .PPS.
>
> 3. You MUST be using the SHM driver (127.127._28_.x), not the NMEA
> driver (127.127._22_.x) for anything even slightly accurate.
>
> 4. If you're doing this on a Pi, please feel free to message me
> offlist and I will happily spend some time with you setting up a
> complete working config to make your own Stratum 1 server.   To get
> your started, here's what I'm uising as my /etc/ntp.conf on my stratum
> 1 server:  https://pastebin.com/7c6P0aYv
>
> I'll also be doing some BoF's on Timekeeping at Linux.conf.au next
> year, if anyone wants to nerd away about excessively accurate time
> keeping for ensuring your logs are correct, and displayed in the
> correct order.
>
> --Rob


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