RFC2821 essentially says two things about mail-from. One is where the
string comes from, the other is how it is used by a recipient of the
mail-from.
With respect to the derivation of the string, RFC2821 is wrong.
It's regrettable that this statement,
which has been conserved right through from RFC788, can no longer be
referred back to the original author.
To that end, the name "mail from" is wrong and should, instead, be
something like "bounces to".
OK, now I am confused. In the document at
http://www.imc.org/ube-sol.html
You refer to
"[...] domain name given by a sending SMTP server during the MAIL FROM
command in SMTP. If the originator is on a list of prohibited sites [...]"
After previously defining
"An originator creates a message"
I read this as claiming that the originator address (sender) is given in
MAIL FROM. Is this document wrong as well? Or have I just misread it?
--
The best is the enemy of the good
Voltaire (1694-1778)