In marid-core draft says in section 7.2 it is written:
7.2 E-Mail Forwarders
A program that forwards received mail to other addresses MUST add an
appropriate header that contains an email address that it is
authorized to use. Such programs SHOULD use the Resent-From header
for this purpose.
But this recomendation for Forwarders to use Resent-From header directly
contradicts what is written in section 3.6.6 of the RFC2822:
Note: Reintroducing a message into the transport system and using
resent fields is a different operation from "forwarding".
"Forwarding" has two meanings: One sense of forwarding is that a mail
reading program can be told by a user to forward a copy of a message
to another person, making the forwarded message the body of the new
message. A forwarded message in this sense does not appear to have
come from the original sender, but is an entirely new message from
the forwarder of the message. On the other hand, forwarding is also
used to mean when a mail transport program gets a message and
forwards it on to a different destination for final delivery. Resent
header fields are not intended for use with either type of forwarding"
--
William Leibzon
Elan Networks
william(_at_)elan(_dot_)net