[exim] message-id related spam filtering is rejecting my mai…

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Lähettäjä: Ian P. Christian
Päiväys:  
Vastaanottaja: exim-users
Aihe: [exim] message-id related spam filtering is rejecting my mails...
A user on a server of mine recently forwarded me this:

---------------------------------------------------

Your message triggered a spam alert on my system (i.e. it didn't show as
definitely spam but it contained warning signs).

Checking, the problem is the header line:

     Message-ID: <006801c70fd2$f74520c0$1064a8c0@James>


RFC 2822 says (section 3.6.4):

    The message identifier (msg-id) itself MUST be a globally unique
    identifier for a message.  The generator of the message identifier
    MUST guarantee that the msg-id is unique.
    [...]
    Though other algorithms will work, it is
    RECOMMENDED that the right hand side contain some domain identifier
    (either of the host itself or otherwise) such that the generator of
    the message identifier can guarantee the uniqueness of the left hand
    side within the scope of that domain.


This message-ID does not meet that criterion, since anyone can claim "James"
as their own.

Digging further, I find that this ID was probably derived from:

     Received: from mail.domain.co.uk (hope.domain.co.uk
[x.x.x.x])
         by lists.domain.org.uk (Postfix) with ESMTP id 5AA091EF08E
         for <list@???>;
         Fri, 24 Nov 2006 14:20:39 +0000 (GMT)
     Received: from [y.y.y.y] (helo=James)
         by mail.domain.co.uk with esmtpa (Exim 4.62)
         (envelope-from <user@???>)
         id 1Gnbuw-0004hA-7C; Fri, 24 Nov 2006 14:20:38 +0000


The problem is therefore twofold:
- your mail software is using the name "James" in the HELO instead of
"james.custdomain.com" or some such;
- you (whether on "James" or mail.domain.co.uk) aren't inserting a
legal message-ID, and checking that it's legal.

If you would like me to continue to read your pearls of wisdom, I suggest
you get this fixed ASAP.

----------------------------------------


I however fail to see the issue here:

Firstly, is this not typical of anyone using windows for their HELO to
be given as the computer name?

Secondly, the RFC says 'RECOMMENDED' there, so I don't really see what
the problem is anyway.

Who's in the wrong?

Thanks,

Ian