RE: The open relay problem.

On Wed, 24 Mar 2004, Seth Goodman wrote:

> With the present SPF+SRS, if there is a forwarder, you have to trust that
> the forwarder did the SPF check properly and you have to accept their local
> SPF policy.  Since you, in general, have no way of knowing either of these,
> you can't know how much trust to put in a particular forwarder's assertion
> of your point #2 above.  That is a key limitation of the present SPF+SRS
> scheme.  The alternate scheme that I proposed does not suffer from this
> since the destination gateway MTA has all the tools it needs to verify the
> mail source itself.

Classical game theory would argue that if such a forwarder was performing
SPF incorrectly, it would be treated exactly as if it were a source of
spam in its own right. Indeed, the two are always indistinguishable. It is
therefore to be assumed that any valid forwarder will attempt to act in
its own best interest and perform SPF correctly.

S.

-- 
Shevek                                    http://www.anarres.org/
I am the Borg.                         http://www.gothnicity.org/