David Woodhouse wrote:
On Tue, 2005-02-22 at 00:19 -0500, Stuart D. Gathman wrote:
Can SPF disrupt the delivery of valid eMail?
No. It only disrupts the delivery of email with forged MAIL FROM.
Unfortunately, some people have become accustomed to forging their email,
and complain bitterly when required to say where they are really sending it
from.
Stuart is being somewhat disingenuous with his use of the word 'forged'.
What he refers to as 'forgery' is in fact common practice. When users
forward mail from one site (a vanity domain, old university, old
employer etc.) to a real mailbox elsewhere, it's almost always done with
the original sender's address intact. That's what Stuart calls
'forgery'. And SPF breaks it.
See http://david.woodhou.se/why-not-spf.html for further discussion and
some alternative schemes which you might want to consider instead, which
don't have such problems.
SPF was designed to break this behaviour. Is it forgery? Before SPF it
was an argument, now there is no argument. If I publish -all in _my_
domain and send mail, I have defined forgery as anyone not in that
poliicy attempting to use my domain in the return path of mail they
send. That is the inherent beauty of SPF, if _you_ don't think it is
forgery, then simply publish a record that reflects your wishes. I'll
publish my record.
SPF is a refreshing concept that allows senders to verbalize what _they_
believe should and shouldn't be acceptable use of their domain in the
envelope sender of Internet messages. SPF is expressive and the
Internet is about operating they way you wish -- which is very
symbiotic. If you hate SPF, I think your hatred is misplaced. There is
likely an SPF policy that matches your opinion how others should view
your domain used in an envelope sender.
--
// Theo Schlossnagle
// Principal Engineer -- http://www.omniti.com/~jesus/
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