[188665] in North American Network Operators' Group
Re: Stop IPv6 Google traffic
daemon@ATHENA.MIT.EDU (Owen DeLong)
Mon Apr 11 17:44:54 2016
X-Original-To: nanog@nanog.org
From: Owen DeLong <owen@delong.com>
In-Reply-To: <CAGFn2k2uX+9szrBwnoNiocjG3d8S8dgrfgZFqTC1G=gDAnvWxA@mail.gmail.com>
Date: Mon, 11 Apr 2016 14:44:50 -0700
To: Rubens Kuhl <rubensk@gmail.com>
Cc: Nanog <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
> On Apr 11, 2016, at 14:03 , Rubens Kuhl <rubensk@gmail.com> wrote:
>=20
> On Mon, Apr 11, 2016 at 5:56 PM, Ricky Beam <jfbeam@gmail.com> wrote:
>=20
>> On Sun, 10 Apr 2016 20:09:04 -0400, Rubens Kuhl <rubensk@gmail.com> =
wrote:
>>=20
>>> If your users are seeing captchas, one or a few or them are likely =
to be
>>> infected to the point of generating too much requests to Google.
>>>=20
>>=20
>> If that were the case, they'd be seeing the same via IPv4. And =
apparently,
>> they aren't.
>>=20
>=20
> Nope. If you have both A and AAAA IP addresses in DNS responses and =
have
> both IPv4 and IPv6 connectivity, IPv6 will be preferred, with even a =
bit of
> latency handicap favoring IPv6 in current Happy Eyeballs =
implementations.
> Remember that the symptom is not unresponsive website, but an answer =
with
> an inconvenience (the captcha), so the browser and the network stack =
won't
> deem it as IPv6 load failure.
Also, incorrect or non-existant PTR records are much more common in IPv6
than in IPv4, so that could also account for some difference in =
behavior.
Most res.ISPs, for example, synthesize PTR responses for their IPv4
addresses such as:
240.59.103.76.in-addr.arpa. 7200 IN PTR =
c-76-103-59-240.hsd1.ca.comcast.net.
vs.
; <<>> DiG 9.8.3-P1 <<>> -x 2601:1c1:1234:5678:b834:f36d:2bb9:285
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 48639
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; QUESTION SECTION:
=
;5.8.2.0.9.b.b.2.d.6.3.f.4.3.8.b.8.7.6.5.4.3.2.1.1.c.1.0.1.0.6.2.ip6.arpa.=
IN PTR
;; AUTHORITY SECTION:
0.1.0.6.2.ip6.arpa. 3600 IN SOA dns101.comcast.net. =
dnsmaster.comcastonline.com. 2014093006 7200 300 604800 3600
;; Query time: 128 msec
;; SERVER: 172.22.186.6#53(172.22.186.6)
;; WHEN: Mon Apr 11 14:43:53 2016
;; MSG SIZE rcvd: 171
for example.
Owen
