Bill Hacker wrote: >
> But what is important here is also that Exim appears to NOT have
> been set to act on the missing message-id header in this case - nor
> SpamAssassin.
>
> This appears to be a case of the T-Bird MUA *on it's own* tagging as junk.
No, Bill, you've misunderstood the OP's scenario. Thunderbird and
Outlook are the _sending_ MUAs. Exim is the _sending_ MTA. Hotmail.com
is the recipient MTA and MUA. Hotmail is spam-binning the message sent
by Outlook, and the OP can't figure out why.
So far, we've identified two very plausible differences between the two
messaages which Hotmail could be acting on. We know that Hotmail uses
Sender ID, which obeys SPF records. We also know that Hotmail uses a
number of poorly documented spam filter heuristics, which could be
noticing the missing Message-ID, so that's something the OP should fix
as well.
> IMNSHO, *this* case is just not an Exim issue.
I certainly agree with you on this one, with the small exception that
the OP should definitely configure submission mode for his authenticated
and local submissions, to solve the Message-ID problem.
