On Jul 27, 2004, at 9:50 PM, Douglas Otis wrote:
It could if the MTA either had a valid list of users, or attempted to
deliver down stream to ascertain if the user was valid before
completing
the session. The MTA only knows it will relay for a domain. In the
case of the backup MTA service, this 'knowledgeable' server is expected
to be down. As a shortcut for administration or out of reluctance,
lists of valid users may not be shared with some MTAs relying messages.
Why do you need a list of valid users to do a Sender-ID check?
-andy