/etc/postfix/main.cf

queue_directory = /var/spool/postfix
command_directory = /usr/sbin
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
mail_owner = postfix
unknown_local_recipient_reject_code = 550
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases

inet_interfaces = all
inet_protocols = ipv4
mydestination = localhost

debug_peer_level = 2
debugger_command =
         PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin
         ddd $daemon_directory/$process_name $process_id & sleep 5

sendmail_path = /usr/sbin/sendmail.postfix
newaliases_path = /usr/bin/newaliases.postfix
mailq_path = /usr/bin/mailq.postfix
setgid_group = postdrop
html_directory = no
manpage_directory = /usr/share/man
sample_directory = /usr/share/doc/postfix-2.6.6/samples
readme_directory = /usr/share/doc/postfix-2.6.6/README_FILES

# 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

relay_domains = *
virtual_alias_maps=hash:/etc/postfix/vmail_aliases
virtual_mailbox_domains=hash:/etc/postfix/vmail_domains
virtual_mailbox_maps=hash:/etc/postfix/vmail_mailbox

virtual_mailbox_base = /var/vmail
virtual_transport = virtual
virtual_minimum_uid = 2222
virtual_uid_maps = static:2222
virtual_gid_maps = static:2222

smtpd_sasl_auth_enable = yes
smtpd_sasl_type = dovecot
smtpd_sasl_path = /var/run/dovecot/auth-client
smtpd_sasl_security_options = noanonymous
smtpd_sasl_tls_security_options = $smtpd_sasl_security_options
smtpd_sasl_local_domain = $mydomain
broken_sasl_auth_clients = yes

smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination
#smtpd_relay_restrictions = permit_mynetworks, permit_sasl_authenticated, 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

myhostname = servername.de
#alias_maps = hash:/etc/aliases
#alias_database = hash:/etc/aliases
myorigin = servername.de
#mydestination = $myhostname, servername.de, localhost.de, , localhost
#mydestination = localhost
relayhost =
#mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mynetworks = 0.0.0.0/0
mailbox_size_limit = 0
recipient_delimiter = +
#inet_interfaces = all
#inet_protocols = all

always_bcc = alwaysbcc
recipient_bcc_maps = hash:/etc/postfix/recipient_bcc_maps