Re: [apps-discuss] Malformed mail guidance document (draft-ietf-appsawg-malformed-mail)

["Murray S. Kucherawy" <[e-mail]>]

> -----Original Message-----
> From: [e-mail] [mailto:[e-mail]] On Behalf Of Scott Kitterman
> Sent: Wednesday, February 29, 2012 8:52 PM
> To: [e-mail]
> Subject: Re: [apps-discuss] Malformed mail guidance document (draft-ietf-appsawg-malformed-mail)
> 
> On Wednesday, February 29, 2012 07:56:41 PM Murray S. Kucherawy wrote:
> > Hi all,
> ...
> > When it reappears, I'd love to see some additional review comments,
> > especially the submission of new cases that should be included in the
> > first version.  I imagine there are many.
> 
> One thought that immediately came to mind is that it might be useful to
> mention case changes in header fields in paragraph 7.  "Helpful" MTAs
> doing this have been responsible for more than a few hard to
> troubleshoot DKIM failures.

That's certainly a concern but I'm not sure it's on topic for this draft.  Altering header field name cases is not strictly a malformation, it's a questionable handling choice that doesn't really alter the semantics or interpretation of the message in a meaningful way.  And DKIM does have a way (relaxed header canonicalization mode) to deal with it.

A separate document that lists annoying MTA habits which don't actually result in non-compliant messages would quite possibly be a lot larger than this one.  :-)

-MSK