Postfix Notes

# List the mail queue
postqueue -p
mailq

# Flush the queue (attempt to deliver all queued mail)
postqueue -f
postfix flush

# Delete all queued mail
postsuper -d ALL

# Delete a specific message
postsuper -d <message_id>

# View message content
postcat -q <message_id>

# Hold all mail
postsuper -h ALL

# Release held mail
postsuper -H ALL

apt install libsasl2-2 libsasl2-modules sasl2-bin

smtpd_sasl_auth_enable = yes
smtpd_sasl_security_options = noanonymous
smtpd_sasl_local_domain = $myhostname
broken_sasl_auth_clients = yes
smtpd_recipient_restrictions =
    permit_sasl_authenticated,
    permit_mynetworks,
    reject_unauth_destination

systemctl enable saslauthd
systemctl start saslauthd

# /etc/postfix/main.cf — TLS settings
smtpd_tls_cert_file = /etc/ssl/certs/mail.crt
smtpd_tls_key_file = /etc/ssl/private/mail.key
smtpd_tls_CAfile = /etc/ssl/certs/ca-bundle.crt
smtpd_use_tls = yes
smtpd_tls_auth_only = yes
smtpd_tls_loglevel = 1

smtp_tls_cert_file = /etc/ssl/certs/mail.crt
smtp_tls_key_file = /etc/ssl/private/mail.key
smtp_use_tls = yes

# /etc/postfix/master.cf
smtp      inet  n       -       -       -       -       smtpd
  -o content_filter=sophos-filter:dummy

sophos-filter unix - n n - 10 pipe
  flags=Rq user=sophos argv=/opt/sophos/bin/savmail

127.0.0.1:10026 inet n - n - - smtpd
  -o content_filter=
  -o smtpd_recipient_restrictions=permit_mynetworks,reject
  -o mynetworks=127.0.0.0/8