On Mon, 12 Jan 2004, Meng Weng Wong wrote:
Stephen Satchell has proposed an alternative solution to sender
rewriting.
On Sun, Jan 11, 2004 at 10:41:41PM -0800, Stephen Satchell wrote:
| I have answered some of Wietse's objections to the forwarding question
| by proposing something completely different: the "Forward: " header.
| See my proposal on the PostFix list.
|
| By having the MTA indicate that the message has been forwarded, with
| particulars, using a "Forward:" header line, the reverse traversal
| doesn't require ANY rewriting, yet allows the use of an accurate
| envelope source line.
|
| Forwarded:
| to new-user(_at_)new-domain(_dot_)com
| for this-user(_at_)this-domain(_dot_)com
| by forwarding-server.example.com
| id CD43CAB37
| ; Sat, 10 Jan 2004 15:44:30 -0500 (EST)
|
Last year I became aware that default sendmail configurations all support
receiving mail from both the smtp (25) and submission (587) ports. I was
confused for awhile by sendmail's use of the same "submission" label for
its "submission" daemon, as well as the submission port.
As described in RFC 2476, the initial submission of e-mail by clients to
the first-hop SMTP server should (if the RFC's recommendations are
followed) use port 587, rather than port 25. (Yeah, I know that very
few--if any--mail clients use port 587 ... but most of them can be
configured to use 587 ...)
Section 8 of the RFC ("Message Modifications") discusses information that
the "submission" server can add to a message, that an
intermediate/final-hop SMTP server probably shouldn't: Sender, Date,
Message-ID, Transfer Encoding, Digital Signatures, Encryption, etc.
It would seem that the addition of a Forward: header might also fit in
this category of information that a "submission" server can add.
Can anyone see where making a distinction between "submission" and other
"smtp" connections might help solve (or at least better define or
describe) SPF's latest challenge of how to deal with clients whose IP
addresses don't match the advertised SPF IP addresses of their ISP's
first-hop relay/submission server?
I am hopeful that this submission/relay difficulty can be solved! I would
love to exercise greater control over the envelope sender addresses of
mail that arrives at my server!!
Weldon
--
Weldon Whipple
weldon at whipple.org
-------
Sender Permitted From: http://spf.pobox.com/
Archives at http://archives.listbox.com/spf-discuss/current/
Latest draft at http://spf.pobox.com/draft-mengwong-spf-02.9.4.txt
To unsubscribe, change your address, or temporarily deactivate your
subscription,
please go to
http://v2.listbox.com/member/?listname(_at_)©#«Mo\¯HÝÜîU;±¤Ö¤Íµø?¡