| What are the advantages? Free, and open source! 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 it's 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.
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