Scott Kitterman <spf2(_at_)kitterman(_dot_)com> writes:
How are MTA service providers supposed to validate the authority of their
customers to use mail identities foreign to their service? I don't believe
that there is a good proposal on the table for this. Does anyone know of
one?
Maybe something similar to SPF could be used for this. The shared MTA
will be receiving the email via SMTP from an MUA, MSA or (the
customer's) MTA. So could the domain owner not publish a record
showing the SMTP AUTH identities authorised to use that domain?