dovecot

dovecot [-c config_file] [-F]

-c config_file
    Specifies the configuration file to use. Defaults to /etc/dovecot/dovecot.conf.

-F
    Run Dovecot in foreground mode (for debugging).

Dovecot is an open-source IMAP and POP3 email server, designed with security as its primary goal. It's known for its ease of configuration, high performance, and excellent compatibility with various mail clients.

Dovecot supports various authentication mechanisms, including PAM, LDAP, and SQL, and offers advanced features like mailbox indexing, full-text search, and support for multiple mailbox formats such as mbox and Maildir. It is used as a core component for email services and is widely deployed because of its reliability and security hardening.

Dovecot aims to provide a secure and efficient email server for personal and enterprise use, incorporating features for spam filtering integration and advanced user management.
The software is under active development, adapting to new standards and security needs in email communications.

Dovecot relies heavily on its configuration file; incorrect configurations can lead to security vulnerabilities or service disruptions. It's important to thoroughly review and understand the configuration options.

Also be aware of TLS/SSL configuration for secure connections.

User permissions and file system permissions relating to mail storage are critical and must be set appropriately to prevent unauthorized access.

Dovecot's behavior is controlled by various configuration files located in /etc/dovecot/. The main configuration file is dovecot.conf, but it includes other files, such as conf.d/10-mail.conf, conf.d/10-auth.conf, and others, to separate different configurations for security, authentication, and other features. These files are parsed sequentially, overriding options as needed.

Dovecot supports a wide variety of authentication methods. PAM (Pluggable Authentication Modules) provides a flexible way to integrate with the system's existing authentication mechanisms. LDAP (Lightweight Directory Access Protocol) allows Dovecot to authenticate users against a central directory service. SQL authentication allows querying a database for user credentials. The authentication mechanism is configured in the auth {} block of the configuration files.

Dovecot supports multiple mailbox formats, including mbox and Maildir. Maildir is generally the preferred format due to its superior performance and resistance to corruption. The 'mail_location' setting in the configuration file specifies the location and format of the user's mailboxes. For example, 'mail_location = maildir:~/Maildir' sets Maildir as the mailbox format with user's home directory with subdirectory Maildir.

Security is a primary design goal of Dovecot. Dovecot has multiple features, including built-in protection against common attacks, such as buffer overflows and format string vulnerabilities. It also supports TLS/SSL encryption for secure communication between the server and clients. Properly configuring TLS/SSL and authentication mechanisms are critical for maintaining a secure email environment.

Dovecot was designed as a secure and reliable alternative to existing IMAP servers like UW-IMAP.
Its development focused on defense in depth. It gained popularity due to its security features, performance, and relatively simple configuration compared to other servers.
Dovecot has been under active development by Timo Sirainen, and the open source community, constantly addressing new security threats and implementing the latest email standards, resulting in widespread adoption in various enterprise environments.

mail(1), postfix(1), sendmail(8), imap(8), pop3(8)