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Sender: vs. Resent-From: for bounced messages ▻

Sender: vs. Resent-From: for bounced messages

In article <3np8a1$79h@news.aero.org>, Michael Elkins
<elkins@aerospace.aero.org> wrote:
>I was just reading through rfc822 and I'm a little confused about when
>you're supposed to use Sender: versus the Resent-From: field on resent
>messages.  The rfc states that a Sender: field should be used whenever
>the From: line is not the person who sent the message (ie. the sender
>is not the author of the message).

According to STD 11 (RFC 822), the `From:' field "contains the identity
of the person(s) who wished this message to be sent", whereas the
`Sender:' field "contains the authenticated identity of the AGENT
(person, system or process) that sends the message".  The canonical
example of this is a secretary sending a message on behalf of his/her
boss: see Appendix A.  Note that more than one address can appear in the
`From:' field, whereas there can only be one `Sender:'.

>                                    However, why is there a need for
>the Resent-From field if this is true?  Or does a valid Resent-From
>header imply that a Sender field is not needed?

If you are using the Resent-* headers, then `Resent-From:' and
`Resent-Sender:' have meanings analoguous to `From:' and `Sender:':
the person(s) who wished this message to be resent and the agent that
resends the message respectively.

However, in my opinion it is better to avoid the Resent-* headers
altogether---there are several problems with them.  It is much more
satisfactory to use MIME's message/rfc822 content type to resend a
message.

Tim.
--
Tim Goodwin        | "BIND does not like VM." -- Paul Vixie
Public IP Exchange |

Original headers:

From: tim@pipex.net (Tim Goodwin)
Newsgroups: comp.mail.headers
Subject: Re: Sender: vs. Resent-From: for bounced messages
Date: 28 Apr 1995 15:22:41 +0100
Organization: PIPEX, 216 Science Park, Cambridge, England
Message-ID: <3nqtnh$oq0@pipe.pipex.net>
References: <3np8a1$79h@news.aero.org>

△ comp.mail.* △

◅ Anybody nuked mbox-format mboxes yet??

Sender: vs. Resent-From: for bounced messages ▻