Re: [DNSOP] ANAME loop detection

[Jan Včelák <[e-mail]>]

Matthijs,

On Mon, Jul 8, 2019 at 11:47 AM Matthijs Mekking wrote:
> >> Also what is wrong with an authoritative server already giving out more
> >> optimal answers than just the ANAME and sibling address records?
> >
> > I also understand the sibling address records only as a mean to gap
> > the adoption period. It should not be a feature.
>
> It's not a feature, its an optimization: If the requester receives a No
> Data response to its ANAME query, he can finalize the target lookup with
> an address query to the last target in the chain.

I tend to disagree. I would not mind if this optimization came for
free but we have to deal with ANAME loops due to the existence of
sibling address records.

> > If the DNS provider (i.e. authoritative server) wanted to perform some
> > magic to provide more optimal answer than the resolver could get by
> > resolving the ANAME then there is no point of involving ANAME. You can
> > perform the magic with A/AAAA already.
>
> Not more optimal than the resolver, but more optimal than the default
> sibling address records that are put into the zone.  The benefit of that
> is that the resolver has more sane addresses to hand out to the client
> in case it is unable to perform ANAME target lookup (due to timeout for
> example).

Sorry, I might have misinterpreted what you meant by the "optimal
answer" originally. I think we are in agreement that the sibling
address records resolved by the resolver are preferred to the ones
retrieved from the authoritative server to be used as a last resort.

Jan