Here’s my postfix main.cf file. Plunder it at will.
smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no
# appending .domain is the MUA’s job.
append_dot_mydomain = no
# Uncomment the next line to generate “delayed mail” warnings
#delay_warning_time = 4h
readme_directory = no
#smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
#BKW
smtpd_relay_restrictions = reject_unknown_sender_domain,
reject_unknown_recipient_domain,
reject_unauth_pipelining, permit_mynetworks,
permit_sasl_authenticated, reject_unauth_destination
# check_sender_access hash:/etc/postfix/blacklist,
myhostname = w5gfe.org
alias_maps = hash:/etc/aliases,
hash:/var/lib/mailman/data/aliases
alias_database = hash:/etc/aliases,
hash:/var/lib/mailman/data/aliases
myorigin = w5gfe.org
mydestination = w5gfe.w5gfe.org, w5gfe, w5gfe.org, splat.w5gfe.org, maa.w5gfe.org, ns.w5gfe.org, localhost
relayhost =
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128\ [2001:470:1f0e:9eb::]/64 192.168.1.0/24
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all
inet_protocols = ipv4, ipv6
smtpd_tls_cert_file = /etc/letsencrypt/live/w5gfe.org/fullchain.pem
smtpd_tls_key_file = /etc/letsencrypt/live/w5gfe.org/privkey.pem
smtpd_use_tls = yes
smtpd_tls_session_cache_database = btree:{data_directory}/smtpd_scache smtp_tls_session_cache_database = btree:{data_directory}/smtp_scache
smtpd_sasl_auth_enable = yes
smtpd_sasl_type = dovecot
smtpd_sasl_path = private/dovecot-auth
smtpd_sasl_authenticated_header = yes
smtpd_sasl_security_options = noanonymous
smtpd_sasl_local_domain = $myhostname
broken_sasl_auth_clients = yes
smtp_use_tls = yes
smtpd_tls_received_header = yes
smtpd_tls_mandatory_protocols = SSLv3, TLSv1.1, TLSv1.2, !TLSv1
smtpd_tls_mandatory_ciphers = medium
smtpd_tls_exclude_ciphers = aNULL, DES, 3DES, MD5, DES+MD5, RC4
smtpd_tls_auth_only = yes
tls_random_source = dev:/dev/urandom
smtpd_tls_security_level = may
smtp_tls_security_level = may
smtp_tls_loglevel = 1
smtpd_tls_loglevel = 1
smtpd_tls_received_header = yes
smtpd_recipient_restrictions = reject_unknown_sender_domain,
reject_unknown_recipient_domain,
reject_unauth_pipelining,
permit_mynetworks,
permit_sasl_authenticated,
reject_unauth_destination,
reject_non_fqdn_sender,
reject_invalid_hostname,
reject_non_fqdn_recipient,
check_policy_service inet:127.0.0.1:10023,
permit
proxy_interfaces = 72.24.30.146
## DKIM milter
milter_default_action = accept
milter_protocol = 6
smtpd_milters = inet:localhost:8891
non_smtpd_milters = inet:localhost:8891
# large files OK on April 19, 2016
message_size_limit = 0
compatibility_level = 2
## BlackList stuff November 23, 2018
smtpd_sender_restrictions = check_sender_access hash:/etc/postfix/BlackList