While I agree with the spirit of what you are suggesting - to
restore honesty to the Internet - the reality is we have a
huge installed base of SMTP servers out there. Even if we
agreed today that all forwarding MTAS must rewrite the MAIL
FROM, it will take years - many years - to upgrade them. I
strongly doubt whether we will ever entirely eliminate
today's style of "verbatim" forwarding.
In the interim - which will last a long long time - we need a
solution that does not falsely reject mail when forwarders do
not rewrite MAIL FROM.
I don't mean to take sides on 2821/2822. But one aspect of this does not
seem right to me. Sysadmins by and large will do what is necessary to make
sure that their mail gets through. On a weekly basis we are faced with some
new threat (mail or otherwise) that requires us to
patch/upgrade/filter/block something. We don't exactly get much warning
(and who knows how stable that patch really is), but we deal with it. About
52 times a year.
If some major ISPs told me that they would require a change, and a suitable
fix was available and practical, I would be glad that I got advance warning,
and happy that I didn't find out about it from the boss who didn't get his
powerpoint presentation. Will the big ISPs do it? Dunno.
This group has spent a lot of effort in order to minimize pain on the part
of the community; thanks for that. My 2 bits here is that if you have
thought this out well, and you still have to put the admins through some
work, you have done better than the average week has done to them.
Mark