DBMail - Fast and scalable sql based email services. It's distributed under
terms of GNU GPLv2.

This DBMail build assume to work with MySQL/MariaDB or SQLite, as storage
backends, because both of them are included in Slackware. Authentication
backend can be either SQL or LDAP. On frontend side IMAP4, POP3, SIEVE
protocols are supported. MTA communication can be performed via LMTP or
local client - dbmail-deliver. There is an http API daemon to perform
server administration. Admin tasks can also be performed via cli tools.

For MySQL/MariaDB backend you should create database, user with password and
grant this user all privilegies on created database. Then you should create
tables via command

'mysql DATABASE -u user -p password < /usr/doc/dbmail-*/create_tables.mysql'.

This user, password and database must be mentioned in /etc/dbmail/dbmail.conf
in apropriate places.

More information about setup DBMail in different configuration environments
you can get at http://www.dbmail.org/dokuwiki/doku.php.