[80108] in North American Network Operators' Group
Re: DNS Round Robin
daemon@ATHENA.MIT.EDU (Florian Weimer)
Mon Apr 25 19:11:47 2005
From: Florian Weimer <fw@deneb.enyo.de>
To: Roy <garlic@garlic.com>
Cc: nanog@merit.edu
Date: Tue, 26 Apr 2005 01:11:14 +0200
In-Reply-To: <426AC44A.80103@garlic.com> (garlic@garlic.com's message of "Sat,
23 Apr 2005 14:55:22 -0700")
Errors-To: owner-nanog@merit.edu
> My theory is as follows. The query causes the caching NS to get the two
> answers but the software stores them in numerical order. The default
> for bind is to "round-robin" so it choses the first (and thus the lower
> IP address) as the first value. Since the TTL is zero, the software
> then discards the data so it never gets to select the second value in
> its robin robin scheme.
>
> Does this sound plausible?
It's plausible. I would assume this behavior without looking at the
source code, too.
> Has anyone else observed this? Is it a bug or a feature?
It's a feature. Anything which discourages the use of TTL 0 is a
feature.
