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

Miroslav Lichvar <mlichvar@redhat.com> Tue, 10 September 2019 10:17 UTC

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Date: Tue, 10 Sep 2019 12:17:19 +0200
From: Miroslav Lichvar <mlichvar@redhat.com>
To: Hal Murray <hmurray@megapathdsl.net>
Cc: ntp@ietf.org
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References: <mlichvar@redhat.com> <20190910074704.GB21704@localhost> <20190910093623.BA37A406063@ip-64-139-1-69.sjc.megapath.net>
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Subject: Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Extension Field drafts -- Four separate drafts
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On Tue, Sep 10, 2019 at 02:36:23AM -0700, Hal Murray wrote:
> 
> mlichvar@redhat.com said:
> > IIRC, there are few implementations that do that. openntpd is probably the
> > most widely used one. As a server, it just checks if the packet is 48 or 64
> > octets long and that the mode is 1 or 3. ...
> 
> What's the 64 byte case?
> 
> I'm trying to make it fit with old style shared key authentication (no 
> extension field) but that's 20 or 24 bytes, 4 bytes for the key-ID and 16 or 
> 20 for MAC.

You are right. I didn't look correctly. It's actually 68. It doesn't
verify the MAC and always responds with a plain 48 octet packet, so
I'm not sure what is the point of accepting such request.

-- 
Miroslav Lichvar