Dear Friends, I have signed up with a 3rd party smtp server as relay host. This server needs the following lines in the main.cf of our server instead of relayhost direction:
smtp_sender_dependent_authentication = yes sender_dependent_relayhost_maps = hash:/etc/postfix/sender_relay smtp_sasl_auth_enable = yes smtp_sasl_security_options = noanonymous smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd This is working fine. However, all the senders/domains not listed in sender_relay file are still able to send emails directly from our email server. How can I block this? I mean sender not listed in sender_relay file should not be able to send any email from our Postfix server. Thanks.
