Stephane Bortzmeyer wrote:
2) "fetchmail", meaning the algorithm explained in
http://www.imc.org/ietf-mxcomp/mail-archive/msg04356.html
Not very different from spf2.0/mailfrom if I got this right.
The conclusion in RfC 3834 (4) is:
| The Return-Path address is really the only one from the
| message header that can be expected, as a matter of protocol,
| to be suitable for automatic responses that were not
| anticipated by the sender.
I simply believe that, given the current state of the art
about email identities, it is better to have choice.
Yes. For an unmodified PRA to work RfC 2476 could be updated
(8.1 MAY insert Sender => MUST insert Sender), but actually it
would be simpler to fix the algorithm (pretend that a Sender
matching the Return-Path is there if necessary).
Bye, Frank