[159642] in North American Network Operators' Group
=?utf-8?Q?Re=3A_Intermittent_incorrect_DNS_resolution=3F?=
daemon@ATHENA.MIT.EDU (Erik Levinson)
Wed Jan 16 23:11:32 2013
Date: Wed, 16 Jan 2013 23:09:39 -0500 (EST)
From: "Erik Levinson" <erik.levinson@uberflip.com>
To: "Joe Abley" <jabley@hopcount.ca>
In-Reply-To: <6490C823-9974-4E09-8D79-903630515BF0@hopcount.ca>
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
Thanks Joe and thanks everyone else for the on and off-list replies. Quite =
insightful.=0A=0AI think we've reached the consensus that the problem is th=
e ignoring of TTLs as opposed to misbehaving/stale authoritative servers. S=
o for now I shall wait.=0A=0ATo give an idea of the scale of the problem ri=
ght now, I'm getting thousands of requests per minute to a new IP vs. about=
two requests per minute on the equivalent old IP, with over 60% of the lat=
ter being Baidu, but also a bit of Googlebot and other random bot and non-b=
ot UAs. =0A=0APerhaps next week I'll unbind some old IPs for a few minutes =
to see what happens.=0A=0A-----Original Message-----=0AFrom: "Joe Abley" <j=
abley@hopcount.ca>=0ASent: Wednesday, January 16, 2013 8:57pm=0ATo: "Erik L=
evinson" <erik.levinson@uberflip.com>=0ACc: "Christopher Morrow" <morrowc.l=
ists@gmail.com>, nanog@nanog.org=0ASubject: Re: Intermittent incorrect DNS =
resolution?=0A=0A=0AOn 2013-01-16, at 14:33, Erik Levinson <erik.levinson@u=
berflip.com> wrote:=0A=0A> True...I did try 4.2.2.2 / 8.8.8.8 and some loca=
l ones here. All looked fine.=0A=0AI sent queries from 270+ different locat=
ions for the domains you mentioned off-list and I didn't see any inconsiste=
ncies. The persistent host-caching/browser-caching theories seem like your =
best bet (or my 270+ locations weren't sufficiently diverse to catch a stal=
e zone being served by an anycast authority server).=0A=0A=0AJoe=0A=0A
