Re: [DNSOP] Comment on section 2 of draft-ietf-dnsop-nxdomain-cut-05.txt

[Matthew Pounsett <[e-mail]>]

On 28 September 2016 at 06:42, Edward Lewis <[e-mail]> wrote:

> On 9/27/16, 18:46, "Matthew Pounsett" <[e-mail]> wrote:
> >Would it be better then to leave early expiry as an implementation choice
>
>
> Ultimately, the goal of the draft is to tell a recursive server that if it
> can conclusively deduce existence of a name from what it has cached, it is
> allowed to do so.  Today if the conclusion is positive, that's how it is.
> The draft proposes to add negative conclusions as well.  Perhaps getting
> into the details of managing what's in the cache, which is not covered
> beyond TTL expiry "rules" is causing the wrapping around the axle.  (We are
> talking about the fairly odd example of there being conflicting data.)
>
>
Taking the view that this is only about interoperability, then I would say
the implementor MAY treat names below the NXDOMAIN response as nonexistent,
and MAY choose to expire those names early... perhaps with a suggestion
that this might be the better choice for data coherence, but still leave it
up to the implementor if they've got a better reason to do it otherwise.