February 21, 2020 4:00 PM, "Wietse Venema" <[email protected]> wrote:
> [email protected]: > >> Hello, >> >> I would like to progressively restrict the ability for users to >> impersonate other email addresses when they use our authenticated >> SMTP (Postfix + Dovecot). We have about 2500 users on this SMTP >> server but we have about 50K total users and 60K email adresses. >> As a first step I would like to setup a diagnostic to find out who >> is sending emails that would violate a given smtpd_sender_login_maps, >> without triggering a true Reject. A line in the log file would be >> great. >> >> Is that possible? > > Postfix has a universal "warn if you would reject" feature: > > /etc/postfix/main.cf: > smtpd_mumble_restrictions = > ... > warn_if_reject reject_sender_login_mismatch > ... > > It's designed for testing new rules. It rings a bell, my bad! Thanks a lot Patrick
