Determining Which Authoritative Sever to Use

[Tony Finch]

Bob McDonald <bmcdonaldjr at gmail.com> wrote:
>
> My question is this; how do the recursive servers determine from
> the information in the stub zone which name server to query?

As well as what Bob Croswell said about SRTT (which is entirely correct),
there's a subtlety with stub zones in particular.

A stub zone works a bit like the root zone hints, in that the name servers
that you configure are just used to find the zone's NS records. This means
that stub zones don't override where queries are routed for these zones.
If you want your resolver to ignore the NS records on your internal zones,
you should use static-stub instead.

Regarding anycast, it isn't necessary for internal authoritative servers
unless your organization is really huge (and probably not even then): it
is simpler to just use the DNS's standard reliabilty features. All you
need to do is have more than one authoritative server for each zone.
On the other hand, anycast is a good way to improve the availability and
maintainability of your resolvers, because your users' devices talk
directly to them, and if they don't work there might as well not be an
Internet connection.

-- 
Tony Finch  <fanf at isc.org>  (he/they)  Cambridge, England
Selsey Bill to Lyme Regis: East or southeast, veering south later, 2
to 4. Smooth or slight, occasionally moderate for a time offshore.
Fair. Good.