[Mailman-Users] Detecting mail with multiple From: lines

[Barry Warsaw]

On May 24, 2011, at 11:29 AM, Stephen J. Turnbull wrote:

>Barry Warsaw writes:
>
> > What's the legitimate use case for multiple From headers?
>
>Technically, there is none.  RFC 5322 requires exactly one From field,
>and that's that.  http://www.ietf.org/rfc/rfc5322.txt, table in
>section 3.6.  (Resent-From, of course, is a different kettle of fish.)
>
>However, presumably multiple addresses in the From field (same URL,
>section 3.6.2) would have the same effect on Mailman's (current)
>filtering strategy.

Actually, I think MM3 could handle either case:

                field_values = self.get_all(header, [])
                senders.extend(address.lower() for (real_name, address)
                               in email.utils.getaddresses(field_values))

-Barry

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