Postfix configuration
Postfix configuration can be a bit tricky sometimes, and usually involves few files to work properly.
These are the relevant parameters I use.
Main configuration file (main.cf)
Basic options
inet_interfaces = 127.0.0.1 192.168.11.35 inet_protocols = all mydomain = mydomain.tld myhostname = volstagg.mydomain.tld myorigin = $mydomain mynetworks = 127.0.0.0/8 192.168.11.0/24 mydestination = $myhostname, localhost.mydomain.tld, localhost, mail.mydomain.tld, mydomain.tld smtpd_banner = $myhostname ESMTP $mail_name (GNU/Linux) biff = no append_dot_mydomain = no compatibility_level = 2 alias_maps = hash:/etc/aliases alias_database = hash:/etc/aliases sender_canonical_maps = pcre:/etc/postfix/sender_canonical recipient_delimiter = + mailbox_size_limit = 0 message_size_limit = 51200000
- for a satellite system mydomain can be set to myhostname
compatibility_levelturns on backward compatibility warning log messages.
See http://www.postfix.org/COMPATIBILITY_README.html
Relay host
smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination relayhost = [smtp.relay.tld]
TLS parameters
smtpd_use_tls=yes
smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
SASL authentication
smtp_sasl_auth_enable = yes smtp_sasl_password_maps = hash:/etc/postfix/sasl/passwd smtp_sasl_type = cyrus smtp_sasl_security_options = noanonymous
SASL passwords map
The passwords map contains the credentials to authenticate to one (or more) smtp relays:
smtp.my.domain.tld user@my.domain.tld:<password> smtp.other.domain.tld user@other.domain.tld:<password>
Issue the command:
postmap /etc/postfix/sasl/passwd
to create the corresponding hash map.