postfix

Identity

• Unit: postfix.service (systemd); master process is /usr/lib/postfix/sbin/master
• Config: /etc/postfix/main.cf (main parameters), /etc/postfix/master.cf (daemon table)
• Queue dirs: /var/spool/postfix/ — subdirs: active, deferred, hold, incoming, corrupt
• Logs: journalctl -u postfix, /var/log/mail.log (Debian/Ubuntu), /var/log/maillog (RHEL/Fedora)
• Ports: 25/tcp (SMTP), 587/tcp (submission/MSA), 465/tcp (SMTPS legacy)
• Distro install: apt install postfix / dnf install postfix
• Lookup table rebuild: postmap /etc/postfix/<table> — required after editing hash-type maps

Key Operations