Re: ntptrace returns stratum 16, ntpq -p shows sync with stratum 2 server. - NTP

This is a discussion on Re: ntptrace returns stratum 16, ntpq -p shows sync with stratum 2 server. - NTP ; It may be a mistake to use the pool servers; I never had worse time resolution until I tried them. I modified a program that I found on the Internet : "NTPClient is a C# class designed to connect to ...

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Thread: Re: ntptrace returns stratum 16, ntpq -p shows sync with stratum 2 server.

  1. Re: ntptrace returns stratum 16, ntpq -p shows sync with stratum 2 server.

    It may be a mistake to use the pool servers; I never had worse time
    resolution until I tried them.

    I modified a program that I found on the Internet : "NTPClient is a C# class
    designed to connect to time servers on the Internet.
    /// The implementation of the protocol is based on the RFC 2030."

    and rewrote it in Java to read the time from many stratum 1 and 2 servers
    for several days at 60 second intervals in round-robin fashion and then
    picked the servers that consistently had the lowest delay times and the
    highest precision. This is much better than the pool servers becasue with
    them you cannot control either precision or delay time.

    CHE
    wrote in message
    news:1151338233.735502.124990@p79g2000cwp.googlegr oups.com...
    > I've googled for this problem and generally it seems to be caused by a
    > networking problem, although I can't see anything that would indicate
    > that. I'm running ubuntu , with only a couple of changes from the
    > default configuration... uncommenting the pool NTP server, and adding a
    > local ISP ntp server. I've been playing with this all afternoon, and
    > I've come against a dead end. I'll probably realise I've done something
    > stupid as soon as I send this off :-)
    >
    > to start off:
    >
    > # ntptrace
    > localhost.localdomain: stratum 16, offset -0.025048, synch distance
    > 0.012000
    >
    > # ntpq -p
    > remote refid st t when poll reach delay offset
    > jitter
    > ================================================== ============================
    > *fortitude.route 82.96.64.2 2 u 56 64 377 10.235 -105.53
    > 23.437
    > +fiordland.ubunt 193.79.237.14 2 u 60 64 377 11.248 -95.855
    > 24.182
    > xclock-b.develoo 192.12.19.20 2 u 53 64 377 564.283 -348.56
    > 47.912
    > LOCAL(0) LOCAL(0) 13 l 55 64 377 0.000 0.000
    > 0.002
    >
    > # ntpq -c rv
    > assID=0 status=c624 sync_alarm, sync_ntp, 2 events,
    > event_peer/strat_chg,
    > version="ntpd 4.2.0a@1:4.2.0a+stable-8-r Fri Sep 9 16:44:48 UTC 2005
    > (1)"?,
    > processor="i686", system="Linux/2.6.12-9-386", leap=11, stratum=16,
    > precision=-19, rootdelay=0.000, rootdispersion=13.275, peer=7780,
    > refid=INIT, reftime=00000000.00000000 Thu, Feb 7 2036 6:28:16.000,
    > poll=6, clock=0xc84a82b7.98087442, state=3, offset=-25.048,
    > frequency=0.000, noise=36.622, jitter=22.695, stability=0.000
    >
    >
    >
    > and here's my ntp.conf
    >
    >
    >
    >
    >
    > # /etc/ntp.conf, configuration for ntpd
    >
    > # ntpd will use syslog() if logfile is not defined
    > #logfile /var/log/ntpd
    >
    > driftfile /var/lib/ntp/ntp.drift
    > statsdir /var/log/ntpstats/
    >
    > statistics loopstats peerstats clockstats
    > filegen loopstats file loopstats type day enable
    > filegen peerstats file peerstats type day enable
    > filegen clockstats file clockstats type day enable
    >
    >
    > # You do need to talk to an NTP server or two (or three).
    > server ntp.keme.net iburst #isp's ntp server
    > server ntp.ubuntulinux.org
    >
    > # pool.ntp.org maps to more than 100 low-stratum NTP servers.
    > # Your server will pick a different set every time it starts up.
    > # *** Please consider joining the pool! ***
    > # *** ***
    > server pool.ntp.org
    >
    > # ... and use the local system clock as a reference if all else fails
    > # NOTE: in a local network, set the local stratum of *one* stable
    > server
    > # to 10; otherwise your clocks will drift apart if you lose
    > connectivity.
    > server 127.127.1.0
    > fudge 127.127.1.0 stratum 13
    >
    > # By default, exchange time with everybody, but don't allow
    > configuration.
    > # See /usr/share/doc/ntp-doc/html/accopt.html for details.
    > restrict default kod notrap nomodify nopeer noquery
    >
    > # Local users may interrogate the ntp server more closely.
    > restrict 127.0.0.1 nomodify
    >
    > # Clients from this (example!) subnet have unlimited access,
    > # but only if cryptographically authenticated
    > #restrict 192.168.123.0 mask 255.255.255.0 notrust
    >
    > # If you want to provide time to your local subnet, change the next
    > line.
    > # (Again, the address is an example only.)
    > #broadcast 192.168.123.255
    >
    > # If you want to listen to time broadcasts on your local subnet,
    > # de-comment the next lines. Please do this only if you trust everybody
    > # on the network!
    > #disable auth
    > #broadcastclient
    >




  2. Re: ntptrace returns stratum 16, ntpq -p shows sync with stratum 2 server.

    Thanks for all of the responses

    Just a followup on the situation (I always feel that not enough people
    say exactly what happened in the end on usenet posts like these)

    I think it was just down to having too few servers, and NTP not being
    confident about which ones to synchronise with. I didn't actually
    change the setup as it was at the end of the day. I came back about 18
    hours later, and everything was running fine.

    as for the burst option... I only used burst with the ISPs ntp server,
    because we're paying them. I didn't want to do a DLink! :-)

    When I have another look at the ntp configuration, I'll pick out 4 or
    so good servers which are nearby on the network, and to avoid the pool.

    Thanks all!


  3. Re: ntptrace returns stratum 16, ntpq -p shows sync with stratum 2 server.

    wrote in message
    news:1152180508.533379.132010@j8g2000cwa.googlegro ups.com...
    [...]
    > as for the burst option... I only used burst with the ISPs ntp server,
    > because we're paying them. I didn't want to do a DLink! :-)


    Burst, or iburst?

    Nobody minds iburst. Nobody needs burst[0].

    Groetjes,
    Maarten Wiltink

    [0] Unless you do. But as a rule, nobody does.



  4. Re: ntptrace returns stratum 16, ntpq -p shows sync with stratum2 server.

    Maarten Wiltink wrote:
    > wrote in message
    > news:1152180508.533379.132010@j8g2000cwa.googlegro ups.com...
    > [...]
    >
    >>as for the burst option... I only used burst with the ISPs ntp server,
    >>because we're paying them. I didn't want to do a DLink! :-)

    >
    >
    > Burst, or iburst?
    >
    > Nobody minds iburst. Nobody needs burst[0].
    >
    > Groetjes,
    > Maarten Wiltink
    >
    > [0] Unless you do. But as a rule, nobody does.
    >
    >


    I believe that burst is a special purpose hack with a few, very few,
    legitimate uses. Unfortunately, the documentation fails to explain
    under what circumstances it might be legitimately used!

    When in doubt, DON'T!!

  5. Re: ntptrace returns stratum 16, ntpq -p shows sync with stratum 2 server.

    "Richard B. Gilbert" wrote in message
    news:RImdnWFw1a-u-zDZnZ2dnUVZ_rGdnZ2d@comcast.com...
    [...]
    > I believe that burst is a special purpose hack with a few, very few,
    > legitimate uses. Unfortunately, the documentation fails to explain
    > under what circumstances it might be legitimately used!


    One set of circumstances was mentioned here once. It's possible for
    ARP cache entries to sometimes expire between polls of a server on
    the local network. In that case, some polls will and others will not
    incur a delay while the MAC address is retrieved, increasing jitter.
    Burst can alleviate that.

    This is not a problem for most people.


    > When in doubt, DON'T!!


    Good advice.

    Groetjes,
    Maarten Wiltink



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