[146105] in North American Network Operators' Group
Re: Performance Issues - PTR Records
daemon@ATHENA.MIT.EDU (Larry Smith)
Wed Nov 2 21:34:44 2011
From: Larry Smith <lesmith@ecsis.net>
To: nanog@nanog.org
Date: Wed, 2 Nov 2011 20:33:45 -0500
In-Reply-To: <4979DA6C-6B78-4032-B024-3977A822182F@gmail.com>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Wed November 2 2011 20:27, Matt Chung wrote:
> I assumed that the applications would take absent records into
> consideration instead of waiting and timing out before responding with
> data. Trying to troubleshoot this issue from the limited visibility is
> difficult ; the latency the application is introducing is abstracted
> (unless I am unaware of that troubleshooting technique).
When you mis-place your keys do you only look in one place and then give
up? The calling server does not know there is "no" record until it exhausts
its list of DNS servers, which is probably what is introducing the delay you
are seeing (each server trying to find a PTR with each of its upsteams) until
they all time out...
--
Larry Smith
lesmith@ecsis.net
