--- Douglas Otis <dotis(_at_)mail-abuse(_dot_)org> wrote:
An alternative would be to isolate such mail into a sub-domain, as
example sales(_at_)third-party(_dot_)example(_dot_)com(_dot_) Perhaps there
would be an
explicit indication that the local-part for this domain is not
'assured' (as a type of second class mail). For the local-part to be
assured, it would then be sent through their servers where keys have
explicit means to indicate such an assurance. The explicit key
assertion, such as 'l=y' within the key, would then not require nor
encourage per-user keys.
You want to require all mail sent via a third party to use a subdomain?