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[Ntp] SNTP and extension fields (WAS: Re: Antw: Re: Antw: Re: Antw: [EXT] NTPv5 Loop Detection without Stratum)

kristof.teichel@ptb.de Tue, 06 September 2022 09:50 UTC

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References: Message from "Ulrich Windl" <Ulrich.Windl@rz.uni-regensburg.de> of "Tue, 06 Sep 2022 08:23:16 +0200." <6316E754020000A10004D6D4@gwsmtp.uni-regensburg.de> <20220906070439.08DEE28C1D8@107-137-68-211.lightspeed.sntcca.sbcglobal.net>
To: Hal Murray <halmurray@sonic.net>
Cc: "ntp@ietf.org" <ntp@ietf.org>, ntp <ntp-bounces@ietf.org>, Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de>
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Date: Tue, 06 Sep 2022 11:50:09 +0200
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Subject: [Ntp] SNTP and extension fields (WAS: Re: Antw: Re: Antw: Re: Antw: [EXT] NTPv5 Loop Detection without Stratum)
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> 
> Ulrich.Windl@rz.uni-regensburg.de said:
> > Yes, but a "packet format" does not mean a fixed-length packet IMHO; 
instead
> > if should contain a mechanism for a variable number of optional fields 
that
> > can have a variable length and should be parseable even if it's only 
to
> > ignore them. I think that is what the e tension fields had in mind, 
but
> > somewhat short-sighted. 
> 
> You are tangling 2 threads.  The chunk you are replying to is discussing 
SNTP.
> 
> The S is for Simple.  I hope SNTP will work without extension fields.
> 

Wouldn't that preclude use of NTS?
(It would, and also that of any other security measures other than v3-era 
symmetric key MAC with unspecified key exchange, if I'm not mistaken...) 

If that's correct: can we afford to rule out modern (well-scaling) 
authentication for any and all SNTP clients?

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