On Tue, Apr 28, 2015 at 09:03:51AM +0200, Marco wrote: > I would like to understand why the null envelope sender address ("<>") is > always permitted for all logins, even if it doesn't match the > smtpd_sender_login_maps table. > reject_authenticated_sender_login_mismatch works as expected for all other > envelopes.
This address can't be reasonably owned by any particular login. If any of your submission clients are MTAs, they need to be able to send bounces. If you don't want to allow authentication submission from the null sender address, you can restrict that sender address via access(5): null-sender: <> permit_mynetworks, reject_unauth_destination main.cf: unindexed = texthash:${config_directory}/ smtpd_sender_restrictions = check_sender_access ${unindexed}null-sender, reject_sender_login_mismatch smtpd_relay_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination ... -- Viktor.