Rejecting unlisted senders in Postfix
Solution 1:
The first option apply to all local senders, the second permit to have a criteria like:
smtpd_sender_restrictions =
check_sender_access hash:/etc/postfix/acl_unknown_permited
reject_unlisted_sender
on file /etc/postfix/acl_unknown_permited
[email protected] permit
The 'permit' inside /etc/postfix/acl_unknown_permited make restriction process jump to smtpd_recipient_restriction without process reject_unlisted_sender. The right hand of file support a acl list, like:
[email protected] permit_mynetworks, reject
This create many possiblilities.