Re: [Exim] multiple PTR and HELO check

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Author: Philip Hazel
Date:  
To: Giuliano Gavazzi
CC: exim-users
Subject: Re: [Exim] multiple PTR and HELO check
On Mon, 23 Jun 2003, Giuliano Gavazzi wrote:

> Sorry if this has been discussed, I have the impression it might, but
> it appears that exim does not deal well with multiple PTR records.
> I have received an email (spam) with:
>
> Received: from mail.univie.ac.at ([131.130.1.27] helo=mailbox.univie.ac.at)
>
> but
>
> ;; ANSWER SECTION:
> 27.1.130.131.in-addr.arpa. 60402 IN     PTR     mail.univie.ac.at.
> 27.1.130.131.in-addr.arpa. 60402 IN     PTR     mailbox.univie.ac.at.

>
> so it looks like exim stopped at the first PTR.


Exim sets up $sender_host_name to the first name it is given by
gethostbyaddr(). It also sets up a list of host alias names from any
aliases that it is given. These are used in various checks. For example,
if in an ACL you say

hosts = some.host.name

then the name and its aliases are all checked.

However, aliases are not used when creating the $sender_rcvhost variable
that is used by default in the Received: header line.

I am not sure what, if anything, should be done about this, because a
host could potentially have a very large number of alias names.

--
Philip Hazel            University of Cambridge Computing Service,
ph10@???      Cambridge, England. Phone: +44 1223 334714.
Get the Exim 4 book:    http://www.uit.co.uk/exim-book