[RndTbl] programatically determine if DNS is down or blocked?

wyatt@prairieturtle.ca wyatt at prairieturtle.ca
Thu Apr 7 07:51:04 CDT 2016

dig has parameters to force cache bypass.


----- Reply message -----
From: "Trevor Cordes" <trevor at tecnopolis.ca>
To: "Robert Keizer" <robert at keizer.ca>
Cc: "Continuation of Round Table discussion" <roundtable at muug.mb.ca>
Subject: [RndTbl] programatically determine if DNS is down or blocked?
Date: Wed, Apr 6, 2016 15:41

On 2016-04-06 Robert Keizer wrote:
> Why don't you use dig+grep+sed in bash?

Ya, that's one of the ideas (dig).  It looks like dig will
differentiate between named down, vs blocked 53, vs simple invalid

I'm trying to see if there are other ways also, perhaps ones that don't
require a fork.  And the dig will send out real queries to real
servers, but I guess it will be tempered by the cache?  I'll have to
test what dig does in the different failure modes when a) resolving a
domain that isn't cached vs b) resolving one that is cached.
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