On Wed, 8 Sep 2004, David Cantrell wrote:
You forget, SPF doesn't just tell you who is authorised to speak on behalf of foobar.com, it also tells you who is *not* authorised.
That is sort of implied, yes.
If you get mail coming in from - eg - randomgibberish.comcast.net claiming to be from foobar.com, then you know that it's dodgy unless foobar.com's SPF record says that that cable modem address is authorised.
Except that, SPF records are as easy to setup for a spammer, as for you and I. If the above is a spammer, then SPF for foobar.com will list randomgibberish.comcast.net as an authorised sender. SPF will absolutely not have any effect on spam. And I say this merely as a disciple of Vixie - he thought of a form of SPF /years/ ago, and he knew /years/ ago it wouldnt do anything for Spam. The only difference between Vixie's MAIL-FROM MX records and SPF is the snake-oil: Vixie was honest in his claims for what it could do, the hype around SPF is not. regards, -- Paul Jakma paul@clubi.ie paul@jakma.org Key ID: 64A2FF6A Fortune: Reformatting Page. Wait...