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
smtp_tls_CAfile=/etc/postfix/ssl/ca_chain.pem
smtpd_tls_security_level=may
smtp_tls_security_level=may
smtpd_tls_loglevel = 1
smtp_tls_loglevel = 1

smtp_tls_policy_maps = hash:/etc/postfix/tls_policy

mydomain = celestis.csnu.org
append_dot_mydomain = yes
myhostname = celestis.csnu.org
myorigin = /etc/mailname
mydestination = celestis.csnu.org, localhost.localdomain, localhost

relayhost =
smtp_sasl_password_maps =

mynetworks = 127.0.0.0/8

relay_domains =
relay_recipient_maps =

#inet_interfaces = 127.0.0.1, [::1], 88.190.225.214, [ipv6]
#inet_protocols = all
inet_interfaces = 127.0.0.1, 88.190.225.214
inet_protocols = ipv4

alias_maps = proxy:hash:/etc/aliases


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