Re: [dnsext] WG opinion on draft : Improvements to DNS Resolvers, for Resiliency, Robustness, and Responsiveness

[Tony Finch <[e-mail]>]

On Thu, 24 Feb 2011, Brian Dickson wrote:
>
> There is an odd corner case to consider, but I'm not sure if it's been
> considered, and I think it is something which is slightly more likely
> to occur nowadays than in the distant past:
>
> Suppose a nameserver serves both a particular zone, and a
> great(^n)-grandchild zone.
> (E.g. a nameserver serving some TLD, and simultaneously doing DNS
> hosting for third parties.)
> Suppose also, that some intermediate zone(s), great(^n-1)-grandchild,
> parent of the great(^n)-grandchild zone, is *not* served by this
> nameserver,. but is delegated elsewhere. That "other" server then
> delegates back to "this" server, for the great(^n)-grandchild zone.
>
> An iterative resolver, directed to this (TLD) server by the root
> server(s), when querying for the great(^n)-grandchild zone, gets back
> an answer for the great(^n)-grandchild *directly* (no passing "go"),
> including that zone's authority data.
> It gets that without ever chaining through the delegations from the
> TLD through the great(^n-1)-grandchild zone(s).

See for example audns.net.au.

I seem to remember the Australian 1LD / 2LD nameserver situation being
rather tangly until some time relatively recently, though I can't right
now find any documents describing the changes.

Tony.
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