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

[Adam Thompson]

Trevor, why don't you just pay $5/month for a VPS somewhere out on the 
'net (in Canada, even!) with static IP addresses and use that as your 
central coordination point?  If it's still just the principle of the 
thing, well, keep flogging away at it.
-Adam



On 16-04-07 05:50 PM, Hartmut W Sager wrote:
> But obviously, no number of local parameters can dictate what happens 
> to DNS resolving beyond your local infrastructure (LAN).  Even if 
> there were parameters that "suggest" behaviour to upstream servers, 
> those servers could ignore that.  I suspect that full zone file 
> retrieval (or full zone file content retrieval) commands might be the 
> only way to be sure that caching is bypassed.
>
> Hartmut W Sager - Tel +1-204-339-8331, +1-204-515-1701, 
> +1-204-515-1700, +1-810-471-4600, +1-909-361-6005
>
>
> On 7 April 2016 at 07:51, wyatt at prairieturtle.ca 
> <mailto:wyatt at prairieturtle.ca> <wyatt at prairieturtle.ca 
> <mailto:wyatt at prairieturtle.ca>> wrote:
>
>     dig has parameters to force cache bypass.
>
>     Daryl
>
>     ----- Reply message -----
>     From: "Trevor Cordes" <trevor at tecnopolis.ca
>     <mailto:trevor at tecnopolis.ca>>
>     To: "Robert Keizer" <robert at keizer.ca <mailto:robert at keizer.ca>>
>     Cc: "Continuation of Round Table discussion"
>     <roundtable at muug.mb.ca <mailto: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
>     domain.
>
>     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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