Postfix sample

smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU)
biff = no
disable_vrfy_command = yes
smtpd_helo_required = yes

smtpd_tls_cert_file=/etc/postfix/ssl/postfix.pem
smtpd_tls_key_file=/etc/postfix/ssl/postfix.key
smtpd_tls_CAfile=/etc/postfix/ssl/ca_chain.pem
smtpd_tls_loglevel = 1
smtpd_tls_security_level=may
smtp_tls_CAfile=/etc/postfix/ssl/ca_chain.pem
smtp_tls_security_level=may
smtp_tls_loglevel = 1

smtp_tls_policy_maps = hash:/etc/postfix/tls_policy

mydomain = celestis.csnu.org
append_dot_mydomain = no
myhostname = celestis.csnu.org
myorigin = /etc/mailname
mydestination = celestis.csnu.org, localhost.localdomain, localhost

relayhost =
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128

relay_domains =
relay_recipient_maps =

inet_interfaces = all
inet_protocols = all

alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases

smtpd_sasl_auth_enable = no
smtpd_sasl_local_domain = $myhostname   

smtpd_sender_restrictions =
  reject_unknown_sender_domain,
  reject_non_fqdn_sender

smtpd_recipient_restrictions =
  permit_inet_interfaces,
  permit_mynetworks,
  permit_sasl_authenticated,
  reject_non_fqdn_hostname,
  reject_non_fqdn_sender,
  reject_non_fqdn_recipient,
  reject_unauth_destination


smtpd_client_restrictions =
  permit_inet_interfaces,
  permit_mynetworks,
  permit_sasl_authenticated,
  reject_unauth_pipelining

smtpd_helo_restrictions =
  permit_inet_interfaces,
  permit_mynetworks,
  permit_sasl_authenticated,
  reject_invalid_helo_hostname,
  reject_non_fqdn_helo_hostname,
  reject_unknown_helo_hostname

smtpd_data_restrictions =
  permit_inet_interfaces,
  permit_mynetworks,
  permit_sasl_authenticated,
  reject_unauth_pipelining