[153534] in North American Network Operators' Group
Re: AAAA's for www.netflix.com
daemon@ATHENA.MIT.EDU (Daniel Roesen)
Thu Jun 7 21:19:47 2012
Date: Fri, 8 Jun 2012 03:19:10 +0200
From: Daniel Roesen <dr@cluenet.de>
To: nanog@nanog.org
Mail-Followup-To: nanog@nanog.org
In-Reply-To: <CAFJiuFq6x6+ioZkeTYNWinqXN9EDS7d=4HReLsH9X0R2bnJxjA@mail.gmail.com>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Thu, Jun 07, 2012 at 04:43:41PM -0700, David Temkin wrote:
> What do you mean? www.netflix.com is dual stacked, which represents
> availability of our website (and PC/Mac streaming clients) to100% of our
> users who have IPv6.
The zero TTL on the CNAME an AAAA RRs makes www.netflix.com
zero-stacked at least for some resolvers:
$ 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.
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.
Best regards,
Daniel
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