Re: [Exim] system_aliases and delivery problem

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Author: Simon Williams
Date:  
To: Miles Davis
CC: exim-users
Subject: Re: [Exim] system_aliases and delivery problem
* On Thu, Jul 11, 2002 at 09:04:48PM BST, Miles Davis <miles@???> wrote:
> I came across some very specific circumstances which lead exim to drop
> large amounts of email without any error messages. It happens like this: a
> mail is sent to miles@??? (FQDN or not, tested locally and
> remotely). There is an entry in /etc/aliases like this:
>
> miles:    miles@xenon

>
> The end result is that the mail just disappears; it seems that in the
> second pass through the dnslookup router, is doesn't expand the name
> 'xenon', so if the short version is not in local_domains, something goes
> wrong (I'm a little fuzzy on this point.
>
> Attached is the output of 'exim -d -bV miles' and my configure file in
> question. Is this something I should have realized (that the short host
> name must be present in local_domains?) or is there something else I have
> done wrong?


As far as I understand it, Exim will see that you are trying to send
to a local user 'miles', which is converted to 'miles@xenon' by the
aliases file. It will take xenon and look for any MX records for it,
If there are no MX records for it, Exim will look for an A record
for it. If there are no A records for it, the message should be
bounced back to the envelope-from address.

I have run a test here, which I believe relates to your situation.
In my case, I aliased the local user 'miles' to 'simon@avatar', where
avatar is a machine on my network:

miles:          simon@avatar


avatar has no MX records on my network, although, as I have the
following line in /etc/resolv.conf, the resolver will add
no-dns-yet.org.uk to the end of the host, if the host doesn't already
resolve to an IP address:

search no-dns-yet.org.uk

Exim will pass the DNS A record lookup request to the resolver, which
will return 192.168.0.4 and Exim should then try to deliver the
message to that machine for simon@???.

In my case, this happens:

simon@dustpuppy:~$ /usr/exim/bin/exim -bt miles
simon@avatar
    <-- miles@???
  envelope to: simon@???
  router = dnslookup, transport = remote_smtp
  host avatar.no-dns-yet.org.uk [192.168.0.4]
simon@dustpuppy:~$


I have 'qualify_domain' set to 'no-dns-yet.org.uk' (Exim 4.04) and
have 'avatar.no-dns-yet.org.uk' as a part of 'local_domans' on avatar
(Exim 3.32).

I get the following in the headers of the mail that arrives on
avatar:

Received: from dustpuppy.no-dns-yet.org.uk ([192.168.0.1])
        by avatar.no-dns-yet.org.uk with esmtp (Exim 3.32 #1)
        id 17Snl1-00006x-00
        for simon@???; Fri, 12 Jul 2002 00:53:59 +0100
Received: from simon by dustpuppy.no-dns-yet.org.uk with local (Exim 4.04)
        id 17Snjs-0006Im-00
        for miles@???; Fri, 12 Jul 2002 00:52:48 +0100


In your case, that does the following show?:

/path/to/exim -bt miles

Is there anything in the mainlog (or whatever you have called it) to
show what Exim is doing with the messages? Are there any logs on
xenon which show anything happening to the messages?


--
 Simon Williams <simon@???> **** PGP: 099977D0
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