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From: Vincent Lefevre (vincentvinc17.net)
Date: Thu May 02 2013 - 06:27:35 CDT
On 2013-05-01 07:14:37 -0500, /dev/rob0 wrote:
> On Wed, Apr 24, 2013 at 03:44:19PM -0700, Steve Jenkins wrote:
> > warn_if_reject reject_unknown_reverse_client_hostname,
> Safe, because many large receivers do this as well.
That's interesting. Several months ago, I intended to add it, but
I noticed that legitimate mail I received sometimes contained
"unknown" (at least for some user), e.g.
Received: from <snip> (unknown [22.214.171.124])
by ioooi.vinc17.net (Postfix) with ESMTP id 017ED31D51
for <vincentVINC17.ORG>; Tue, 19 Jul 2011 05:03:52 +0200 (CEST)
and at that time, I thought that the machine didn't have a correct
reverse hostname, so that I thought that adding this option would be
bad. But if I grep all the messages from this IP, I now notice that
for most of them, I get "host1743300226138.direcway.com" instead of
"unknown", which occurs only from time to time. This makes me think
that the "unknown" could just be due to a temporary failure, but
with the above option, the mail wouldn't be rejected (it would just
be delayed from time to time due to the 450 reply, as documented).
Is this correct?
Vincent Lefèvre <vincentvinc17.net> - Web: <http://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <http://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)