Re: [Exim] Problems caused by localhost entry in Received

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Author: Toralf Lund
Date:  
To: Exim Mailing List
Subject: Re: [Exim] Problems caused by localhost entry in Received
Toralf Lund wrote:

> We usually configure our MUAs to send e-mail via SMTP to localhost,
> where Exim is running. This results in a header of the form:
>
> Received: from localhost.localdomain ([127.0.0.1] helo=mydomain)
>     by myhost.mydomain with esmtp (Exim 3.33 #1)
>     id 1AdWvu-0005ks-00
>     for user@domain; Mon, 05 Jan 2004 16:46:22 +0100

>
>
> Now, this seems to cause problems with some blacklists etc. on the net;
> apparently they think "localhost" is evil.


[ ... ]

OK. Thanks for all the response. The consensus of it all seems to be
that the "localhost" entries shouldn't cause problems as a sane setup
won't reject messages based on these alone, and most MTAs will in any
case just check the connecting server, not the originating host (unless
it connects directly) or intermediate relays.

That's what I wanted to hear, of course. I got a bit worried, and, I
guess, drew the wrong conclusions because:

   1. A while back, messages internal to our domain started getting
      blocked, and the reason given was that 127.0.0.1 was an open
      relay, because the Exim was mistakenly set up to also do RBL check
      on outgoing mail, and test all hosts, including localhost. Note
      that this misconfiguration existed for a *long* time before the
      problem started occuring.
   2. My post to a mailing list started getting inexplicably lost just
      after that (so I thought the list server might have classified
      them as spam for the same reason.)
   3. Someone mentioned having a message bounced, and thought it
      happened because it was sent via localhost. They may have been
      wrong, though, and I haven't got the error message, so I can't
      check now.


- Toralf