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[Ntp] Re: NTPv5: Operational use case for server/node identification

Miroslav Lichvar <mlichvar@redhat.com> Wed, 15 July 2026 13:15 UTC

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Date: Wed, 15 Jul 2026 15:15:10 +0200
From: Miroslav Lichvar <mlichvar@redhat.com>
To: "Giovane C. M. Moura" <giovane.moura=40sidn.nl@dmarc.ietf.org>
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CC: Steven Sommars <stevesommarsntp@gmail.com>, marco.davids+ietf@sidn.nl, ntp@ietf.org
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Subject: [Ntp] Re: NTPv5: Operational use case for server/node identification
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On Wed, Jul 15, 2026 at 11:08:29AM +0200, Giovane C. M. Moura wrote:
> I don't think this should be an issue for real clients -- I assume chrony
> and ntpd-rs, and others, bind one source port per association and keep it,
> so the hash is constant and a real client stays pinned.

chrony by default changes source port with each request. That should
be ok per RFC 9109. The filtering algorithm prefers measurements from
the closest server.

As for the server identification, I'd be ok with a new optional
extension field to provide a server ID as a string, something along
the lines of the current draft ID.

-- 
Miroslav Lichvar

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