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Thread: Excessive DNS queries for NTP pool addresses

  1. #11
    First officer
    Join Date
    Feb 2014
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    Aldershot, Hampshire. UK
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    262
    Quote Originally Posted by Sweetpants View Post
    For what it's worth, I own my own Stratum 0 (GPS) NTP server so wanted to use that one, I use a local DNS server with RPZ functionality to redirect all *.pool.ntp.org queries to my local NTP server.
    I think you will find you have a stratum 1 NTP server, only government and very large private entities would have a stratum 0 server (the GPS satellites have stratum 0 servers, anything synced to that would be stratum 1)
    I also run a stratum 1 GPS NTP server using a STM32 based system, things like the Raspberry pi don’t have the speed or precision to handle the required timing.
    FR24 F-EGLF1, Blitzortung station 878, OGN Aldersht2, PilotAware PWAldersht, PlanePlotter M7.

  2. #12
    Passenger
    Join Date
    Sep 2018
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    2
    Hmm, this is what ntpq -pn shows on my clock

    remote refid st t when poll reach delay offset jitter
    ================================================== ============================
    127.127.1.0 .LOCL. 10 l 265m 64 0 0.000 0.000 0.000
    o127.127.20.0 .GPS. 0 l 8 16 377 0.000 0.002 0.002
    -193.67.79.202 .GPS. 1 u 61 64 377 26.226 2.585 0.895
    +131.188.3.221 .DCFp. 1 u 58 64 377 21.905 1.676 1.460
    *131.188.3.222 .GPS. 1 u 39 64 377 22.745 1.701 1.520
    +131.188.3.223 .PZF. 1 u 47 64 377 22.390 1.934 0.589

  3. #13
    Purser
    Join Date
    Jan 2015
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    T-EGKK39
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    I guess it means the time source you're using (the GPS) itself is stratum 0. (Wackypedia gives a good write up).

    I took another route and added all the ntp.pool hostnames FR24feed looks up to /etc/hosts and pointed them to my local GPS NTP server.

    Maybe it's time to email FR24 again as the latest client still does a bunch of NTP lookups every ten minutes, looking up hosts on every continent! Doh!!!

  4. #14
    Purser
    Join Date
    Jan 2015
    Location
    T-EGKK39
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    112
    For anyone who has this thread bookmarked, v1.0.24-2 just released updates the NTP code:

    By default only one geographically close server queried every twenty minutes instead of six servers, one on each continent every ten minutes. Still a little often, but MUCH better than before!

    I also noticed "Synchronization delayed, received back-off response" in the log file, which seems to cause it to wait 30 seconds.

    And the icing on the cake - the option to use a local server without faffing around with etc/hosts ! (ntp-server="<ip address>" in /etc/fr24feed.ini)

    Well done, FR24!

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