Hardening Postfix Put restrictions on servers sending mail to you. postconf -e 'smtpd_recipient_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_unauth_destination, reject_unknown_recipient_domain' Anonymize Headers Use some regular expressions to prevent some meta data like a client’s ip address from being leaked. echo "/^Received:.*/ IGNORE /^X-Originating-IP:/ IGNORE /^User-Agent:/ IGNORE /^X-Mailer:/ IGNORE" >> /etc/postfix/header_checks Add this file to the postfix c...
