DBMail is an open-source project that enables storage of mail messages in a relational database.
Commercial development and support is also available.
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-deliver, using a pipe interface, or to dbmail-lmtpd, using LMTP (Local Mail Transport Protocol).
These programs take care of injecting the message into the database. Messages can be retreived from the database using dbmail-pop3d, using the POP3 protocol, or dbmail-imapd, using the IMAP4Rev1 protocol.
Emails are stored in the database. This includes attachments. User information is also stored in the database, so users do not need a system account on machines DBMail is running on.
DBMail is primarily developed and tested on the GNU Linux and FreeBSD platforms. Users have also reported successfull deployments on OpenSolaris, NetBSD and OSX.
DBMail is released under the GNU Public Licence (version 2).
POP3: fix a couple of segfaults
increase max debug message size in error logs
IMAP: replace GMutex with pthread_mutex_t; #990
document backlog parameter, and increase the default
backport socket write fix
LMTP: check results in load-test script