[ Thanks to Falko
Timme for this link. ]
“The resulting Postfix server is capable of SMTP-AUTH and TLS
and quota (quota is not built into Postfix by default, I’ll show
how to patch your Postfix appropriately). Passwords are stored in
encrypted form in the database (most documents I found were dealing
with plain text passwords which is a security risk). In addition to
that, this tutorial covers the installation of Amavisd,
SpamAssassin and ClamAV so that emails will be scanned for spam and
viruses. I will also show how to install SquirrelMail as a webmail
interface so that users can read and send emails and change their
passwords.“The advantage of such a “virtual” setup (virtual users and
domains in a MySQL database) is that it is far more performant than
a setup that is based on “real” system users. With this virtual
setup your mail server can handle thousands of domains and users.
Besides, it is easier to administrate because you only have to deal
with the MySQL database when you add new users/domains or edit
existing ones. No more postmap commands to create db files, no more
reloading of Postfix, etc. For the administration of the MySQL
database you can use web based tools like phpMyAdmin which will
also be installed in this howto. The third advantage is that users
have an email address as user name (instead of a user name + an
email address) which is easier to understand and keep in mind.”