Re: SPF I-D for review: draft-schlitt-spf-classic-00.txt

On Sun, 6 Mar 2005, Bruce Lilly wrote:
> On Fri March 4 2005 16:11, Keith Moore wrote:
>
> > I should clarify that by "unauthorized mail" I meant sending a message
> > using MAIL FROM:<address> and/or From:<address> without having the
> > authorization of the party associated with <address>.
>
> There's simply no way to detect that situation in current
> protocols.

That's true in general. However a site can implement a policy such as
"return paths must contain a security tag" (e.g. as specified in BATV)
which allows that site to distinguish between authorized and unauthorized
use of an address in a return path. At the moment the extent of the
interoperability issues with this idea has not yet been examined in
detail.

Tony.
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