[Mimedefang] Blocking Missing Message-ID
Joseph Brennan
brennan at columbia.edu
Thu Apr 12 09:08:18 EDT 2007
--On Thursday, April 12, 2007 18:25 +0800 imacat
<imacat at mail.imacat.idv.tw> wrote:
> Dear all,
>
> Hi. I notice over 2/5 of my "remaining" spams are missing a
> Message-ID, which is then added automatically by my sendmail MTA
> afterwards.
>
> I'm thinking about blocking all the messages without a Message-ID,
> that comes from unauthenticated clients in foreign networks? Is this
> dangerous? Is it possible to block legal mails for this?
Message-ID is not a required field. Some software used by legitimate
organizations to send announcements and newsletters sends without a
Message-ID. You'd miss some professional and hobby communications
if you reject for it being missing.
It's worth scoring for it being missing. See Spamassassin's rule for
MSGID_FROM_MTA_ID.
Joseph Brennan
Lead Email Systems Engineer
Columbia University Information Technology
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