/etc/postfix/main.cf

root@servername:/etc/postfix# cat main.cf
# See /usr/share/postfix/main.cf.dist for a commented, more complete version


# Debian specific:  Specifying a file name will cause the first
# line of that file to be used as the name.  The Debian default
# is /etc/mailname.
#myorigin = /etc/mailname

compatibility_level=2

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

# TLS parameters
smtpd_tls_cert_file = /etc/letsencrypt/live/servername.de/fullchain.pem
smtpd_tls_key_file = /etc/letsencrypt/live/servername.de/privkey.pem
smtpd_use_tls = yes
smtpd_tls_auth_only = yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache

tls_ssl_options = NO_COMPRESSION
tls_high_cipherlist=EDH+CAMELLIA:EDH+aRSA:EECDH+aRSA+AESGCM:EECDH+aRSA+SHA384:EECDH+aRSA+SHA256:EECDH:+CAMELLIA256:+AES256:+CAMELLIA128:+AES128:+SSLv3:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!DSS:!RC4:!SEED:!ECDSA:CAMELLIA256-SHA:AES256-SHA:CAMELLIA128-SHA:AES128-SHA

### outgoing connections ###
smtp_tls_security_level = may
smtp_tls_cert_file = /etc/letsencrypt/live/servername.de/fullchain.pem
smtp_tls_key_file = /etc/letsencrypt/live/servername.de/privkey.pem
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache


# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.

smtpd_sasl_type = dovecot
smtpd_sasl_path = private/auth
smtpd_sasl_auth_enable = yes
broken_sasl_auth_clients = yes

smtpd_recipient_restrictions =
        permit_sasl_authenticated,
        permit_mynetworks,
        reject_unauth_destination

smtpd_helo_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_invalid_hostname, reject_unauth_pipelining, reject_non_fqdn_hostname

smtpd_sasl_security_options = noanonymous

#smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination

myhostname = servername.de
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
#mydestination = $myhostname, servername.de, localhost.de, , localhost
mydestination = localhost
relayhost =
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all
inet_protocols = all

#Handing off local delivery to Dovecot's LMTP, and telling it where to store mail
virtual_transport = lmtp:unix:private/dovecot-lmtp

#Virtual domains, users, and aliases
virtual_mailbox_domains = mysql:/etc/postfix/mysql-virtual-mailbox-domains.cf
virtual_mailbox_maps = mysql:/etc/postfix/mysql-virtual-mailbox-maps.cf
virtual_alias_maps = mysql:/etc/postfix/mysql-virtual-alias-maps.cf,
        mysql:/etc/postfix/mysql-virtual-email2email.cf
always_bcc = alwaysbcc@localhost
recipient_bcc_maps = hash:/etc/postfix/recipient_bcc_maps
queue_directory = /var/spool/postfix