Dbmail 2.2.5

Dbmail is the name of a group of programs that enable the possiblilty of storing and retrieving mail messages from a database. Currently PostgreSQL and MySQL can be used as database backends.
The upcoming version 2.2 that is under development also supports SQLite, an embedded SQL database system, and ldap for storing userdata. Development and support of dbmail is done by IC&S and NFG, two Dutch companies specializing in Linux development and support.
Main features:
Scalability
- Dbmail is as scalable as the database system that is used for the mail storage. In theory millions of accounts can be managed using dbmail. One could, for example, run 4 different servers with the pop3 daemon each connecting to the same database (cluster) server.
Manageability
- Dbmail is based upon a database. Dbmail can be managed by changing settings in the database (f.e. using PHP/Perl/SQL), without needing shell access.
Speed
- Dbmail uses very efficient, database specific queries for retrieving mail information. This is much faster then parsing a filesystem.
Security
- Dbmail has got nothing to do with the filesystem or interaction with other programs in the Unix environment which need special permissions. Dbmail is as secure as the database its based upon.
Flexibility
- Changes on a Dbmail system (adding of users, changing passwords etc.) are effective immediately.
How does it work?
DBMail is made up of several components. A normal MTA (Postfix, SendMail, QMail, Exim) is used for accepting messages. The MTA hands the messages over to dbmail-smtp, using a pipe interface, or dbmail-lmtpd, using LMTP (Local Mail Transport Protocol). These programs take care of delivering the message into the database. Messages can be retreived from the database using dbmail-pop3d, using the POP3 protocol, and dbmail-imapd, using the IMAP4Rev1 protocol.
The whole email is stored in the database. That includes attachments. The DBMail programs do not have to touch the filesystem to retreive or insert emails. User information is also stored in the database, so users do not need an account on the machines DBMail is running on.
Enhancements:
- This release features greatly improved handling of UTF8 email, has many fixes for IMAP protocol errors, and resolves a number of serious memory leaks.
- A new feature was added to dbmail-export to allow fine-grained message selection and post-export deletion.