# See /usr/share/postfix/main.cf.dist for a commented, more complete
# version.


# General settings
# ================

# Internet hostname of this mail system.
myhostname = {{ inventory_hostname }}

# Under Debian, when a file name is specified, the first line of the
# file be used as the SMTP server name.
myorigin = /etc/mailname

# Text shown to connecting clients as part of SMTP greeting.
smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU)

# Listen on all network interfaces and all protocols.
inet_interfaces = all
inet_protocols = all

# Fall-back to using native lookups (/etc/hosts etc) if DNS lookup
# fails. Useful for local overrides of mail servers.
smtp_host_lookup = dns, native

# Recipient delimeter for separating user name from its extension.
recipient_delimiter = +

# Explicitly set maximum allowed mail size that should be accepted.
message_size_limit = {{ mail_message_size_limit }}

# Disable output of Postfix README file paths when invoking postconf.
readme_directory = no

# Use whitelist/blacklist instead of allowlist/denylist in log
# entries.
respectful_logging = no

# Compatibility level for default values. For more details, see:
#     https://www.postfix.org/COMPATIBILITY_README.html
compatibility_level = 3.6


# Local mailbox delivery
# ======================

# List of domains for local transport deliveries.
mydestination = {{ inventory_hostname }}, {{ inventory_hostname_short }}, localhost.localdomain, localhost

# Alias maps for local deliveries (to system accounts).
alias_maps = hash:/etc/aliases

# Alias database that gets updated when invoking "newaliases" command.
alias_database = hash:/etc/aliases

# Disable size limits for local user mailboxes.
mailbox_size_limit = 0

# Disable use of biff service for new mail notifications to local
# users (improves performance).
biff = no

# External command for local mail deliveries.
mailbox_command = procmail -a "$EXTENSION"


# Remote mailbox delivery
# =======================

# List of trusted networks allowed to relay mail through this system.
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128

# Allow relaying only from trusted networks. Do not relay mails for
# domains for which the mail server is not responsible.
smtpd_relay_restrictions = permit_mynetworks
  reject_unauth_destination

# Static relay host to use for outgoing mails from this server.
relayhost = {{ smtp_relay_host }}{% if smtp_relay_host and smtp_relay_host_port %}:{{ smtp_relay_host_port }}{% endif %}


# TLS configuration
# =================

# Allow connecting SMTP clients to use TLS when connecting to the
# host, but do not enforce it.
smtpd_tls_security_level = may

# Use locally-issued self-signed certificates for TLS.
smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key

# Use custom, generated DH parameters for increased security.
smtpd_tls_dh1024_param_file = /etc/ssl/private/{{ inventory_hostname }}_smtp.dh.pem
smtpd_tls_dh512_param_file = /etc/ssl/private/{{ inventory_hostname }}_smtp.dh.pem

{% if smtp_relay_host %}
# Force TLS certificate validation when connecting to relay host using
# the dedicated CA certificate truststore.
smtp_tls_security_level=verify
smtp_tls_CAfile=/etc/ssl/certs/smtp_relay_truststore.pem
{% endif %}

# Enable TLS session cache database for SMTP client. Helps with
# performance and bandwidth usage.
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache