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

[Stephen J. Turnbull]

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.