Eugene Podshivalov: > Let me put it this way: does Postfix do probe for outgoing mail?
reject_unverified_recipient and reject_unverified_sender make no
such distinction. That is a feature, not a bug.
reject_unverified_recipient has been used on internet gateways that
have no complete table of all valid internal recipients. Those
gateways rely on reject_unverified_recipient to probe an internal
system (such as Exchange) and to populate the valid address cache
dynamically.
Wietse
