Linux/Mailserver/Postfix Satellite

Installation

• install postfix

apt-get install postfix

• postfix configuration (automatic during installation or "dpkg-reconfigure postfix")
  • "Satellite System"
  • "domain.de"
  • "smtp.domain.de"

Configuration

• /etc/mailname

localhostname.localdomain

• /etc/postfix/main.cf

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/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtpd_use_tls=yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${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.

myorigin = localhostname.localdomain
myhostname = localhostname.localdomain
mydomain = localdomain
mydestination = vm-dev.mlnet, localhost.mlnet, localhost
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases

relayhost = smtp.domain.de
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = loopback-only
inet_protocols = all

recipient_canonical_maps = hash:/etc/postfix/canonical_recipients
sender_canonical_maps = hash:/etc/postfix/canonical_senders

smtp_tls_note_starttls_offer = yes
smtp_tls_security_level = encrypt
smtp_tls_mandatory_ciphers = high

smtp_sasl_auth_enable = yes
smtp_sasl_security_options = noanonymous noplaintext
smtp_sasl_tls_security_options = noanonymous noplaintext
smtp_sasl_password_maps = hash:/etc/postfix/sasl_password

• /etc/postfix/canonical_recipients

root server@domain.de
postmaster server@domain.de
webmaster server@domain.de
user user@domain.de

• /etc/postfix/canonical_senders

root hostname@domain.de
postmaster hostname@domain.de
webmaster hostname@domain.de
user hostname@domain.de

• /etc/postfix/sasl_password

touch /etc/postfix/sasl_password
echo "smtp.domain.de username:password" > sasl_password
chmod 600 sasl_password

Restart

• reload maps

postmap /etc/postfix/canonical_recipients
postmap /etc/postfix/canonical_senders
postmap hash:/etc/postfix/sasl_password 

• restart address mapping

/etc/init.d/postfix restart