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Re: [Ntp] Antw: draft-ietf-ntp-mode-6-cmds : Issue 1

Harlan Stenn <stenn@nwtime.org> Wed, 20 September 2017 22:42 UTC

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From: Harlan Stenn <stenn@nwtime.org>
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Date: Wed, 20 Sep 2017 15:42:23 -0700
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Subject: Re: [Ntp] Antw: draft-ietf-ntp-mode-6-cmds : Issue 1
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On 9/20/17 12:10 PM, Brian Haberman wrote:
> 
> 
> On 9/19/17 2:52 AM, Ulrich Windl wrote:
>>>>> Brian Haberman <brian@innovationslab.net> schrieb am 18.09.2017 um 19:10 in
>> Nachricht <d5a5ba98-65f2-f2e0-a0ec-40114213fc03@innovationslab.net>:
>>> Ulrich noted that this document does not specify a version number for
>>> the mode 6 commands. I had suggested specifying it as "version 4 (or
>>> earlier)" given that the introduction of mode 6 commands has occurred at
>>> various versions of the protocol starting at RFC 1305. Ulrich pointed
>>> out that the version number drives the interpretation of the status words.
>>>
>>> For people who have implemented or use mode 6 commands, what makes sense
>>> here? Do we need to specify a version number per mode 6 command?
>>
>> Hi!
>>
>> I think there are several issues:
>>
>> 1) Assuming there are different versions (there are!), how can one find out which version the server implements? See 2)
>>
>> 2) if a client requests a version different from the server, what should the server do? The server could respond with a different version number, indicating that it is not willing to respond / privide the information in the format requested. Or the server could respond with a "bad request" status. Finally the server could respond in the format requested... I have slight favor for the first variant unless there is a command to find out what message format versions the server can provide.
>>
>> 3) As it seems to be now, the server ignores the version (versions 2, 3, and 4 all seem to work)
>>
> 
> The above seems to argue for two things:
> 
> 1) A preliminary handshake between an NTP server and the mode6-speaking
> client to determine what version is in use.
> 
> 2) A change to the operating basis of the mode 6 commands in that the
> above mentioned handshake occurs before actually sending the mode 6 command.
> 
> Is that a good representation of what is being asked for?

If it is, I'm thinking we'd want a mode 6 "Identify" command, that would
have this information in a response.  This response would likely contain
different data before/after authentication.

I'd also much rather we had changes to do this that are tested and known
to do what we want instead of codifying what folks hope will be a good
solution.

I'm happy to work with collaborative folks, experienced or not, who want
to dig in to this.

-- 
Harlan Stenn <stenn@nwtime.org>
http://networktimefoundation.org - be a member!

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