[Mimedefang] MD/SA and Outlook

Gary Funck gary at intrepid.com
Tue Jan 18 18:26:54 EST 2005

> Although I've certainly had cases, using Outlook 2003, where Outlook's
> idea of where the headers ended was different from MD's.  The general
> thing these items seem to have had in common is a blank line embedded in
> the headers (which might be something for the original poster to look
> for a bit more closely...)

I've seen Outlook 2000 get confused not by a blank line in the header,
but they the arrangement of the SA preview, and the attached original
e-mail message.  I wrote it off to an interaction between the code
that is adding the attachments, and the action_rebuild() call at
the end of filter_end() (on the 'spam found' path), and the
subsequent action_rebuild() here (which we have eabled):

    # Deal with malformed MIME.
    # Some viruses produce malformed MIME messages that are misinterpreted
    # by mail clients.  They also might slip under the radar of MIMEDefang.
    # If you are worried about this, you should canonicalize all
    # e-mail by uncommenting the action_rebuild() line.  This will
    # force _all_ messages to be reconstructed as valid MIME.  It will
    # increase the load on your server, and might break messages produced
    # by marginal software.  Your call.

Regarding the blank line in the header, I wondered it if might
be some sort of CRLF issue, where, let's say a new header is added
that has only an LF, but the rest of the header is delimited with
CRLF's or vice verse? The RFC's, I believe, say it shouldn't matter,
but I could see where Outlook might occassionallly get confused,
because PC's are so CRLF centric.

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