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

[Kevin A. McGrail]

> Perhaps it makes more sense to flat-out reject such messages, on the same 
> grounds that you would reject malformed SMTP commands. One could have a 
> rejection message that says "violates RFC2822" (with possibly more detail 
> like "multiple subject lines").
>
> What does an MTA do with even more-malformed messages? Could I "legally" 
> submit line noise to an MTA and expect it to deliver it? Or does it just 
> invoke the LDA to drop the gibberish in the user's mailbox and hope the 
> MUA can make sense of it?
>
> (I still think the sender needs to be hit with a cluestick.)

I think rejecting may be draconian but it would be interesting to track the 
amount of legitimate mail with two subject headers.  I can see a lot of 
filters/gateways accidentally adding this to legitimate mail, unfortunately.

However, David, I think if the headers are being actually deleted, they 
should instead be renamed and retained.  X-SUBJECT-DUPLICATE1: or something.

I guess since I've never dealt much with legitimate mail with duplicate 
headers, I wasn't even aware of this as a problem.

Regards,
KAM