system environment/daemons
- postfix - Postfix Mail Transport Agent
- postfix-cdb - Postfix CDB map support
- postfix-ldap - Postfix LDAP map support
- postfix-mysql - Postfix MySQL map support
- postfix-pcre - Postfix PCRE map support
- postfix-pgsql - Postfix PostgreSQL map support
- postfix-sqlite - Postfix SQLite map support