Dovecot is an open-source software IMAP and POP3 server for Linux and other Unix systems. Developed by Timo Sirainen, the first version was released in July 2002.
Dovecot uses its own experimental native format dbox, as well as standard mbox and maildir formats. It is compatible with the implementation of these formats on both UW IMAP and Courier IMAP servers and with mailbox clients, that are working directly. It also includes mechanisms for circumventing the implementation of communication protocols in mail clients.
It also includes a delivery agent with optional Sieve filtration support. Postfix and Exim mail servers can act as authentication interfaces. Support for IPv6, SSL and TLS protocols is a matter of course.