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

Miroslav Lichvar <mlichvar@redhat.com> Wed, 28 August 2019 11:26 UTC

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Date: Wed, 28 Aug 2019 13:26:01 +0200
From: Miroslav Lichvar <mlichvar@redhat.com>
To: ntp@ietf.org
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Subject: Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Extension Field drafts -- Four separate drafts
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On Wed, Aug 28, 2019 at 04:19:29AM -0700, Harlan Stenn wrote:
> On 8/28/2019 4:14 AM, Miroslav Lichvar wrote:
> > Hopefully with something better than the current refid field based on
> > (hashes of) addresses. Something like your suggested-refid proposal,
> > except the extension field would contain both the ID of the server
> > (randomly generated) and the ID of the its reference.
> 
> Extension fields are optional.

Most clients don't need to know the refid, so to me it makes sense for
the refid information to be optional.

> I'm very curious how the ID if the remote server's reference will be
> useful, and not just another attack vector.

It's a random number and not an address. So it should be better than
the NTPv4 refid, right?

> > This could fit into the space of the NTPv4 refid and reference
> > timestamp, but it would take 64 of those 96 bits and I'm not sure if
> > 32 bits is enough for the other new stuff.
> Exactly what do you see as the use-cases for this information in the
> base packet?  Exactly how would this information be used?

It seems you agree it should be optional.

-- 
Miroslav Lichvar