Re: [Ntp] Antw: Re: Antw: Re: Calls for Adoption -- NTP Extension Field drafts -- Four separate drafts

Heiko Gerstung <> Mon, 02 September 2019 08:00 UTC

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Date: Mon, 2 Sep 2019 10:00:41 +0200
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Thread-Topic: [Ntp] Antw: Re: Antw: Re: Calls for Adoption -- NTP Extension Field drafts -- Four separate drafts
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From: Heiko Gerstung <>
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Subject: Re: [Ntp] Antw: Re: Antw: Re: Calls for Adoption -- NTP Extension Field drafts -- Four separate drafts
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Hi Ulrich,

good point. That is why NTP would use that "ID" instead of the IP address to identify itself. That means ntpd could find out timing loops even if they are caused by a routing loop.


Heiko Gerstung 
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On 02.09.19, 08:37 "ntp im Auftrag von Ulrich Windl" < im Auftrag von> wrote:

    >>> Magnus Danielson <> schrieb am 28.08.2019 um 13:30 in
    Nachricht <>se>:
    > I agree. If someone knocks on the door with v5 packets, reply in v5
    > form, if someone knocks on the door with v4 packets, reply in v4 form.
    > As people migrate to v5, they can start using all the benefits from it.
    > For loop‑protection, keeping a list of nodes from the source is a very
    > easy base condition to avoid routing loops, since as an announcement
    But remember that a "note" is NOT "an IP address". With multi-homed hosts you
    can have interesting synchronization loops... ;-)
    > comes in, if none of the nodes in the list is oneself, you may use it,
    > where as if any of the nodes is oneself, a loop is for sure detected.
    > While the trace loop detection mechanism is sufficient in theory, it
    > does not completely solve all loop problems, as transient loops may
    > occur, but it at least avoids problems in the long term.
    > If I only had time to describe all the things I would do to enhance NTP,
    > it has a number of built‑in assumptions which is not useful or correct.
    > Cheers,
    > Magnus
    > On 2019‑08‑28 13:23, Heiko Gerstung wrote:
    >> Why not define a method in v5 that not only protects against degree 1 loops
    > but maybe also against degree 2,3 or n? 
    >> This is what I meant when trying to explain that we should not stick to the
    > existing packet format with its shortcomings.
    >> Regards,
    >>    Heiko
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    > ntp mailing list
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