[Mimedefang] duplicate subject headers {Scanned by vsl mailsafe}

[Jeff Makey]

David Skoll wrote:
>RFC 2822 specifies that a message can have zero
>or one Subject: header.

I stand corrected, but it seems rather arbitrary for MIMEDefang to
enforce the RFC 2822 limit on the number of Subject headers and not on
other headers (e.g., to, reply-to) that have the same limit.  I'll go
out on a limb again with the suggestion that no RFC explicitly allows
an MTA to remove non-compliant Subject headers from e-mail, but I
can't find any prohibitions either (RFC 2821 requires the preservation
of Received headers, but is silent about others).

For the mail I handle, removing headers causes more trouble than it
could ever prevent.  Although I would prefer that such enforcement be
optional, changing the relevant MIMEDefang code is almost as easy as
using a compile-time or run-time setting so I haven't worried much
about it.

                          :: Jeff Makey
                             jeff at sdsc.edu