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

>>> Harlan Stenn <stenn@nwtime.org> schrieb am 21.09.2017 um 00:42 in Nachricht
<fd938fee-ed5c-a0ca-148f-a20a8c72aaa5@nwtime.org>:

> 
> 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.

Why that? You should elaborate on the role of 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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