Re: [Exim] Fixing SPF Forward Problem by Reply-to: Hack?

On Sun, 2004-03-21 at 12:59 -0800, Avleen Vig wrote:
> SPF does FAR more than just verify the sender's address. It prevents
> mail being accepted where the relay machine is not an authorized
> outbound relay. *THIS* stops a significant amount of spam in itself.

I don't understand. SPF attempts to give you some confidence that the
reverse-path on the mail is valid, and being used with the consent of
the sender. It does so by making the flawed assumption that mail from a
given address will originate only from certain IP addresses.

My point is that there are better ways of verifying that the sender's
address is valid for the mail in question. You seem to claim that this
isn't sufficient, and that SPF gives you something more useful than
that.

Please demonstrate a case where spam is blocked by virtue of the fact
that SPF detects that "the relay machine is not an authorized outbound
relay", yet the sender address _is_ valid for the mail in question.

--
dwmw2