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

Heiko Gerstung <> Tue, 03 September 2019 08:31 UTC

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Date: Tue, 3 Sep 2019 10:31:42 +0200
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Thread-Topic: [Ntp] Antw: Re: Calls for Adoption -- NTP Extension Field drafts -- Four separate drafts
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From: Heiko Gerstung <>
To: Hal Murray <>
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Subject: Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Extension Field drafts -- Four separate drafts
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I believe you quoted Harlan (although I agreed to him), most probably this is caused by Outlook for Mac's incredibly bad quoting behavior... Apologies for this ...

I would think that we either carefully craft the v5 packet format in a way that the information required to create a v3/v4 response is still in the same place or, if that is not possible, face the fact that a v4 server cannot respond to a v5 request. This is, IMHO, acceptable. In this case we might change the packet format for v5 so dramatically that the most common v4 implementations will end up ignoring this request. 

But I believe it should be possible to make sure that the v5 packet format allows a v4 server to respond with a v4 packet. The location in the packet for things like the timestamps could be preserved, I guess. What else is copied from the request in v4 implementaions?


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On 03.09.19, 10:21 "Hal Murray" <> wrote:
    >     I'm saying that if a v3 system gets a v4 (or greater) packet, the v3
    >     system should respond with a v3 packet. 
    It can't.  There are fields in a NTP v3 reply that are copied from the request 
    packet.  The v3 only system doesn't know how to find them in a v4 packet.
    (For v3 and v4, they may be in the same place, but that may not be true for 
    These are my opinions.  I hate spam.