Mailu/core/postfix/conf/main.cf

###############
# General
###############

# Main domain and hostname
mydomain = {{ DOMAIN }}
myhostname = {{ HOSTNAMES.split(",")[0] }}
myorigin = $mydomain

# Queue location
queue_directory = /queue

# Message size limit
message_size_limit = {{ MESSAGE_SIZE_LIMIT }}

# Relayed networks
mynetworks = 127.0.0.1/32 [::1]/128 {{ SUBNET }} {{ RELAYNETS }}

# Empty alias list to override the configuration variable and disable NIS
alias_maps =

# Podop configuration
podop = socketmap:unix:/tmp/podop.socket:

# Only accept virtual emails
mydestination =

# Relayhost if any is configured
relayhost = {{ RELAYHOST }}

# Recipient delimiter for extended addresses
recipient_delimiter = {{ RECIPIENT_DELIMITER }}

# Only the front server is allowed to perform xclient
# In kubernetes and Docker swarm, such address cannot be determined using the hostname. Allow for the whole Mailu subnet instead.
smtpd_authorized_xclient_hosts={{ POD_ADDRESS_RANGE or SUBNET }}

###############
# TLS
###############

# General TLS configuration
tls_high_cipherlist = EDH+CAMELLIA:EDH+aRSA:EECDH+aRSA+AESGCM:EECDH+aRSA+SHA256:EECDH:+CAMELLIA128:+AES128:+SSLv3:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!DSS:!RC4:!SEED:!IDEA:!ECDSA:kEDH:CAMELLIA128-SHA:AES128-SHA
tls_preempt_cipherlist = yes
tls_ssl_options = NO_COMPRESSION

# Outgoing TLS is more flexible because 1. not all receiving servers will
# support TLS, 2. not all will have and up-to-date TLS stack.
smtp_tls_security_level = may
smtp_tls_mandatory_protocols = !SSLv2, !SSLv3
smtp_tls_protocols =!SSLv2,!SSLv3
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache

###############
# Virtual
###############

# The alias map actually returns both aliases and local mailboxes, which is
# required for reject_unlisted_sender to work properly
virtual_alias_domains =
virtual_alias_maps = ${podop}alias
virtual_mailbox_domains = ${podop}domain
virtual_mailbox_maps = ${podop}mailbox

# Mails are transported if required, then forwarded to Dovecot for delivery
relay_domains = ${podop}transport
transport_maps = ${podop}transport
virtual_transport = lmtp:inet:{{ HOST_LMTP }}

# In order to prevent Postfix from running DNS query, enforce the use of the
# native DNS stack, that will check /etc/hosts properly.
lmtp_host_lookup = native

###############
# Restrictions
###############

# Delay all rejects until all information can be logged
smtpd_delay_reject = yes

# Allowed senders are: the user or one of the alias destinations
smtpd_sender_login_maps = ${podop}senderlogin

# Restrictions for incoming SMTP, other restrictions are applied in master.cf
smtpd_helo_required = yes

smtpd_client_restrictions =
  permit_mynetworks,
  check_sender_access ${podop}senderaccess,
  reject_non_fqdn_sender,
  reject_unknown_sender_domain,
  reject_unknown_recipient_domain,
  reject_unverified_recipient,
  permit

smtpd_relay_restrictions =
  permit_mynetworks,
  permit_sasl_authenticated,
  reject_unauth_destination

unverified_recipient_reject_reason = Address lookup failure

###############
# Milter
###############

smtpd_milters = inet:{{ HOST_ANTISPAM }}
milter_protocol = 6
milter_mail_macros = i {mail_addr} {client_addr} {client_name} {auth_authen}
milter_default_action = tempfail

###############
# Extra Settings
###############