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Re: AAAA's for www.netflix.com


From: Daniel Roesen <dr () cluenet de>
Date: Fri, 8 Jun 2012 04:23:33 +0200

On Fri, Jun 08, 2012 at 12:11:20PM +1000, Mark Andrews wrote:
$ dig @pdns3.ultradns.org www.netflix.com. A +norec +short
wwwservice--frontend-313423742.us-east-1.elb.amazonaws.com.
$ dig @pdns3.ultradns.org www.netflix.com. AAAA +norec +short
dualstack.wwwservice--frontend-313423742.us-east-1.elb.amazonaws.com.
$ dig @pdns3.ultradns.org www.netflix.com. ANY +short +norec
$

Resolving www.netflix.com using ANY RRtype fails with an empty answer
section in the DNS response.

Which is just plain BROKEN.

Yup.

This DNS trickery seems to be from the "taking a shower, trying not
to get wet" department. And has adverse effects in corner cases. While
playing around, I had periods of time where I couldn't resolve the FQDN
at all, possibly due some caching of the empty response.

It's not DNS trickery.

The "trickery" is returning different CNAMEs for QTYPE=A and QTYPE=AAAA.
I'm not sure what's the goal of that is, but it's 4am here so I have an
excuse of not seeing the light. :)

Best regards,
Daniel

-- 
CLUE-RIPE -- Jabber: dr () cluenet de -- dr@IRCnet -- PGP: 0xA85C8AA0


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