Re: Intermittent incorrect DNS resolution?

Erik Levinson erik.levinson at
Thu Jan 17 04:09:39 UTC 2013

Thanks Joe and thanks everyone else for the on and off-list replies. Quite insightful.

I think we've reached the consensus that the problem is the ignoring of TTLs as opposed to misbehaving/stale authoritative servers. So for now I shall wait.

To give an idea of the scale of the problem right 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 latter being Baidu, but also a bit of Googlebot and other random bot and non-bot UAs. 

Perhaps next week I'll unbind some old IPs for a few minutes to see what happens.

-----Original Message-----
From: "Joe Abley" <jabley at>
Sent: Wednesday, January 16, 2013 8:57pm
To: "Erik Levinson" <erik.levinson at>
Cc: "Christopher Morrow" <morrowc.lists at>, nanog at
Subject: Re: Intermittent incorrect DNS resolution?

On 2013-01-16, at 14:33, Erik Levinson <erik.levinson at> wrote:

> True...I did try / and some local ones here. All looked fine.

I sent queries from 270+ different locations for the domains you mentioned off-list and I didn't see any inconsistencies. The persistent host-caching/browser-caching theories seem like your best bet (or my 270+ locations weren't sufficiently diverse to catch a stale zone being served by an anycast authority server).


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