[Exim] Received header lines IP address lookup

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Auteur: John Horne
Datum:  
Aan: Exim Users List
Onderwerp: [Exim] Received header lines IP address lookup
Hello,

I've noticed a few times that mail I get from our mailhubs have the
following header line:

Received: from [141.163.66.132] (helo=tracy.csd.plymouth.ac.uk) by
jhorne.csd.plymouth.ac.uk with esmtp (Exim 4.04) id 17BDZe-000530-00 for
john@???; Fri, 24 May 2002 12:49:34 +0100

It's the first line that confuses me. My understanding is that my local MTA
(on jhorne.csd...) is receiving a message from a host with IP address
141.163.66.132, and the HELO command says it is 'tracy.csd.plymouth.ac.uk'.
However, I thought that exim did a reverse lookup of the IP address and
compared this to the HELO name. If they are the same then the Received:
header line should look different. I would expect it to look like:

Received: from tracy.csd.plymouth.ac.uk (141.163.66.132) by

My thought is that exim is not getting a DNS reverse lookup for the mailhub
- if it got anything which didn't match then it would have shown that, but
it's not showing anything. However, the DNS entry is there and the mailhubs
local caching name server is well aware of its own name and IP address - I
ran 'dig' on the mailhub itself.


Anyone any thoughts on this? (This is, of course, this weeks 'Friday
afternoon problem' :-) )


Regards,

John.

------------------------------------------------------------------------
John Horne, University of Plymouth, UK           Tel: +44 (0)1752 233914
E-mail: jhorne@???
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