At 11:16 AM 3/30/2004, Kelson Vibber wrote:
With a "-all" default, the end-user can reject mail that doesn't really
come from you, but runs the risk that a non-SRS forwarding service might
have passed something along.
With a "?all" default, the end-user cannot reject forged mail, but it
*can* give some positive weight to *verified* mail.
Er, replace "end-user" with "recipient server."
And the key thing about ?all is that, if no other components of your record
match the sender, the recipient should treat it as if there were no SPF
record at all.
Basically, ?all good for testing and for transition periods (such as trying
to get all your users to stop using remote servers.)
Kelson Vibber
SpeedGate Communications <www.speed.net>