Meng Weng Wong <mengwong(_at_)dumbo(_dot_)pobox(_dot_)com> wrote :
I tried to address this problem at http://spf.pobox.com/objections.html
under "The Traveling Mailman Problem".
"the IP address from which the mail was sent" is not a specific
concept. SPF only operates within the context of a single SMTP
transaction, testing the TCP client IP. if you are travelling, but can
connect to your home SMTP server, there is no problem.
If my home smtp server is in new england, but i am travelling in australia, the
speed and reliability of my connection are bound to be very poor. You and I
both recognize the advantage of using a local mail relay instead of always
being bound to a single mail relay across the world. Plus, as you said, "if
you can connect"... A lot of ISPs and corporate networks filter port 25.
With VSMTP, you are bound to the server across the world, on a well known,
unfiltered port, for a very short time. (Port 80.) After that, you may send
the message through the local mail relay. Advantage #1: It works. Advantage
#2: It's much faster than sending the whole message across the world. #3:
100% backward compatible.
Are you familiar with SASL AUTH?
I am familiar enough to know that it is used to authenticate the sender. But
when a person receives the message, they don't know if the sender was
authenticated or not. The message could have come from anybody.
A cookie-style proposal such as you suggest has been recently posted to
the SPF list.
see
http://archives.listbox.com/spf-discuss(_at_)v2(_dot_)listbox(_dot_)com/200310/0049.html
http://archives.listbox.com/spf-discuss(_at_)v2(_dot_)listbox(_dot_)com/200309/0017.html
Thank you, I very much like what MJD said. I'm trying to contact him now.
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