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Re: "reject_unknown_reverse_client_hostname" bouncing mail when name server is down

From: Wietse Venema (wietseporcupine.org)
Date: Wed Aug 23 2006 - 20:31:48 CDT


Jordan Russell:
[ Charset ISO-8859-1 unsupported, converting... ]
> (Postfix 2.3.2, Red Hat Enterprise Linux 4)
>
> In Postfix I'm using:
>
> smtpd_recipient_restrictions = .. reject_unknown_reverse_client_hostname
> unknown_client_reject_code = 554
>
> BIND runs on the same machine. /etc/resolv.conf is set as follows:
>
> nameserver 127.0.0.1
>
> I have found that when I stop the "named" daemon, all incoming mail is
> rejected with:
>
> 554 5.7.1 Client host rejected: cannot find your reverse hostname
>
> Yet the manual states:
>
> "The reply is always 450 in case the address->name lookup failed due to
> a temporary problem."
>
> Does an unreachable name server not count as a "temporary problem"?

That depends entirely on what your SYSTEM library routines do.

Don't shoot Postfix. It is only the MESSENGER.

        Wietse