Re: [Ntp] NTPv5 draft

[Dieter Sibold <[e-mail]>]

On 1 Dec 2020, at 11:03, Miroslav Lichvar wrote:

> On Tue, Dec 01, 2020 at 10:51:22AM +0100, Dieter Sibold wrote:
>> On 1 Dec 2020, at 9:12, Miroslav Lichvar wrote:
>>> You mean to require all NTP packets to be authenticated? I don't 
>>> like
>>> that idea. The improvements in NTPv5 are orthogonal to 
>>> authentication.
>>> NTPv5 is not supposed to be more secure. An NTP client that doesn't
>>> want to implement the complexity of NTS shouldn't be restricted to
>>> NTPv4.
>>>
>>
>> Yes, I would propose that by default each NTP packet has to be
>> authenticated. Not using security should be an active decision! I 
>> don’t
>> think that security and increased time sync performance have to be
>> orthogonal. The 2-step approach could provide better time sync 
>> performance
>> and security.
>
> Ok, so if the draft said something like "NTP clients SHOULD use
> authentication", would that work for you? Ultimately, it would be up
> to the client's default configuration whether authentication is
> enabled or not.
>

No. From my point of view this is not explicit. I would prefer that the 
basic protocol incorporates security. That would allow to use security 
without thinking about which approach needs to be applied to accomplish 
that. For the experts there might be additional option like the 
pre-shared key approach to acknowledge very specific circumstances. But 
the normal NTP  user should be able to use a secured NTPv5 like using a 
https protected website.

Obviously the wg needs to discuss about the objectives of NTPv5. This 
could be done, e.g., by adding a section about NTPv5’s objectives to 
the draft. Additionally we could also start a separate document for 
that.

Greetings Dieter


>>> Isn't that the NTP root delay and dispersion? Together they provide 
>>> an
>>> estimate of the maximum error in the receive and transmit timestamp.
>>
>> Uncertainty and maximum error are different. The uncertainty interval 
>> will
>> always be smaller or equal to the max. error.
>
> Can you describe an example how would the server determine the
> uncertainty?
>
> -- 
> Miroslav Lichvar