# -----------------------------
# BASIC SETTINGS
# -----------------------------
myhostname = mail.EXAMPLE.COM        # Replace EXAMPLE.COM with your domain
myorigin = /etc/mailname
# For more virtual hosts chain them: example1.com, example2.com etc.
mydestination = $myhostname, EXAMPLE.COM, localhost
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128

inet_interfaces = all
inet_protocols = all
compatibility_level = 3.6

# -----------------------------
# TLS SETTINGS
# -----------------------------
# Certificates (replace EXAMPLE.COM with your domain)
smtpd_tls_cert_file = /etc/letsencrypt/live/mail.EXAMPLE.COM/fullchain.pem
smtpd_tls_key_file  = /etc/letsencrypt/live/mail.EXAMPLE.COM/privkey.pem
smtpd_tls_CAfile    = /etc/letsencrypt/live/mail.EXAMPLE.COM/chain.pem

# Inbound TLS
# "medium" is useful because older (but surprisingly common) mailservers can send email to you. To be more strict set it to: "high", but you will lose e-mails.
smtpd_tls_security_level = may
smtpd_tls_auth_only = yes
smtpd_tls_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
smtpd_tls_ciphers = medium
smtpd_tls_mandatory_ciphers = medium
smtpd_tls_loglevel = 1
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
tls_preempt_cipherlist = yes
tls_high_cipherlist = ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-RSA-AES256-SHA384

# Outbound TLS
smtp_tls_security_level = may
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtp_tls_CApath = /etc/ssl/certs
smtp_tls_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
smtp_tls_ciphers = high
smtp_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
smtp_tls_mandatory_ciphers = high

# -----------------------------
# AUTHENTICATION (Dovecot SASL)
# -----------------------------
smtpd_sasl_type = dovecot
smtpd_sasl_path = private/auth
smtpd_sasl_auth_enable = yes
smtpd_sasl_security_options = noanonymous
smtpd_sasl_local_domain =

# -----------------------------
# SPAM / RELAY PROTECTION
# -----------------------------
smtpd_recipient_restrictions =
    permit_mynetworks
    permit_sasl_authenticated
    reject_unknown_sender_domain
    reject_unauth_destination
    reject_invalid_hostname
    reject_non_fqdn_recipient
    reject_rbl_client zen.spamhaus.org

smtpd_data_restrictions = reject_unauth_pipelining
smtpd_helo_restrictions =
    permit_mynetworks
    reject_invalid_helo_hostname
    reject_non_fqdn_helo_hostname
    permit

disable_vrfy_command = yes
smtpd_etrn_restrictions = reject

# Rate limiting / anti-abuse
smtpd_client_connection_rate_limit = 10
smtpd_error_sleep_time = 5s
smtpd_soft_error_limit = 5
smtpd_hard_error_limit = 10
smtpd_helo_required = yes
smtpd_discard_ehlo_keywords = silent-discard, dsn

# -----------------------------
# MAILBOX
# -----------------------------
home_mailbox =
mailbox_transport = lmtp:unix:private/dovecot-lmtp
mailbox_size_limit = 0
recipient_delimiter = +

# -----------------------------
# MILTER / DKIM
# -----------------------------
smtpd_milters = unix:/run/opendkim/opendkim.sock
non_smtpd_milters = unix:/run/opendkim/opendkim.sock
milter_default_action = accept
milter_protocol = 6