Re: [DNSOP] Clarifying referrals (#35)

[Dick Franks <[e-mail]>]

On 29 November 2017 at 23:13, Tony Finch <[e-mail]> wrote:

>
>
> On 29 Nov 2017, at 21:18, Dick Franks <[e-mail]> wrote:
>
> On 29 November 2017 at 12:17, Andrew Sullivan <[e-mail]>
> wrote:
>>
>>
>> Right, and the authoritative server can't proceed, but the referral is
>> necessary.  Good, this is helpful, thanks.  This also means, of
>> course, that in such a response the answer section isn't empty.  Is
>> this why you call it a "partial referral"?
>>
>
> And said referral could be to an arbitrary node in the DNS tree,  i.e.
> possibly "upward"?
>
> Or am I missing something?
>
>
> In this case we’re dealing with an authoritative answer containing a CNAME
> pointing out of the server’s authoritative data.
>
> If the server is authoritative only, then there are three cases: (1) the
> CNAME points to a child zone, so the authority section contains a referral
> - this is the partial answer plus referral case that Mark described; (2)
> the CNAME points to a different non-child zone and the server provides full
> answers, in which case the authority section contains the apex records of
> the zone containing the CNAME owner; or (3) same as (2) but the server
> sends minimal answers with an empty authority section.
>
> If it is a 1034 hybrid rec+auth server, the 4.3.2 algorithm step 4
> requires the same referral in case (1) because there is a “delegation from
> authoritative data”; in case (2) you get an implicit referral from the
> cache (which can be upwards).
>

I get the picture.  Many thanks