Alex van den Bogaerdt writes:
On Mon, Aug 15, 2005 at 07:25:58AM +0200, Ralf Doeblitz wrote:
Did you mean that the return-address may not be identical to the address of
the original sender?
Sure, that is the case when there is an intermediate destination.
See RFC821, "2. THE SMTP MODEL", paragraph 2:
"Once the transmission channel is established, the SMTP-sender
sends a MAIL command indicating the sender of the mail."
This sentence is clearly using "sender" it two different ways. The
SMTP-sender (sender of SMTP commands, meaning an MTA, MSA, or MUA) and
the "sender of the mail" (sending email address) specified in the MAIL
command are entirely different concepts.
Whether the "sender of the mail" (MAIL FROM) is the originating sender
or forwarding sender is ambiguous, at least in that sentence.
In "3.2 FORWARDING" error 551:
"The receiver refuses to accept mail
for this user, and the sender must either redirect the mail
according to the information provided or return an error
response to the originating user."
Again, 'sender' and 'originating user' are different.
Different yes, but not in any relevant way. Again 'sender' is the
SMTP command sender, just as the 'receiver' is the SMTP command
receiver, not the addressee. In particular, 'sender' as used above is
not an email address and has no bearing on what email address should
be given by the MAIL command.
SMTP commands have senders and receivers. Email has senders and
recipients. It would help if English had slightly different words for
the two kinds of sender too.
Dick St.Peters, stpeters(_at_)NetHeaven(_dot_)com
Gatekeeper, NetHeaven, Saratoga Springs, NY