My mail server appears not to send encrypted mail.
Image of red padlock in Gmail indicating unencrypted
It seems like most of the information/tutorials focus on setting up TLS so that a client can connect, which I believe I have achieved. I've learned that in the config file, SMTPD is mainly focused on receiving mail. I believe I'm missing some SMTP parameters, have tried a few, but no luck.
This is from my postconf - n:
alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
append_dot_mydomain = no
biff = no
inet_interfaces = all
inet_protocols = ipv4
mailbox_size_limit = 0
mydestination = localhost
myhostname = xxxxxx.com
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
myorigin = /etc/mailname
readme_directory = no
recipient_delimiter = +
relayhost =
smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
smtpd_recipient_restrictions = permit_sasl_authenticated permit_mynetworks reject_unauth_destination
smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
smtpd_sasl_auth_enable = yes
smtpd_sasl_path = private/auth
smtpd_sasl_type = dovecot
smtpd_tls_auth_only = yes
smtpd_tls_cert_file = /etc/letsencrypt/live/xxxxxxx/fullchain.pem
smtpd_tls_key_file = /etc/letsencrypt/live/xxxxxxxx/privkey.pem
smtpd_use_tls = yes
virtual_alias_maps = mysql:/etc/postfix/mysql-virtual-alias-maps.cf
virtual_mailbox_domains = mysql:/etc/postfix/mysql-virtual-mailbox-domains.cf
virtual_mailbox_maps = mysql:/etc/postfix/mysql-virtual-mailbox-maps.cf
virtual_transport = lmtp:unix:private/dovecot-lmtp