Installation Guide

Target Platform

As part of improving maintainability and sustainability, Dovecot has defined a target platform specification and a minimum language standard beginning with version v2.4.0.

The target platform specification is POSIX.1-2008.

A C99/C11 compatible compiler is required, optimally with GNU extensions available.

Currently glibc 2.17 is assumed to be the lowest supported C Standard library version, although others (e.g. older versions or musl) might work as well, although not explicitly tested.

Dovecot CE is maintained and tested for Linux. Other distributions - especially BSD derivatives (e.g. FreeBSD, OpenBSD, macOS, etc.) - are maintained on a best-effort basis only.

Dovecot CE Repositories

The Dovecot team provides packages of Dovecot components for various Linux distributions.

Details can be found at: https://repo.dovecot.org/.

Compiling Dovecot From Source

NOTE

Dovecot is provided by package managers on most popular operating systems, and we also provide packages at https://repo.dovecot.org/. We encourage you to use these instead of building sources yourself.

For most people it is enough to do:

$ ./configure
$ make
$ sudo make install

That installs Dovecot under the /usr/local directory. The configuration file is in /usr/local/etc/dovecot.conf. Logging goes to syslog's mail facility by default, which typically goes to /var/log/mail.log or something similar. If you are in a hurry, you can then jump to quick configuration.

If you have installed some libraries into locations which require special include or library paths, you can pass them in the CPPFLAGS and LDFLAGS environment variables. For example:

$ CPPFLAGS="-I/opt/openssl/include" LDFLAGS="-L/opt/openssl/lib" ./configure

You'll need to create two users for Dovecot's internal use:

• dovenull

  • Used by untrusted imap-login and pop3-login processes, default_login_user setting.

• dovecot

  • Used by slightly more trusted Dovecot processes, default_internal_user setting.

Both of them should also have their own dovenull and dovecot groups. See System Users for more information.

Compiling Dovecot From Git

If you got Dovecot from Git, for instance with

$ git clone https://github.com/dovecot/core.git dovecot

you will first need to run ./autogen.sh to generate the configure script and some other files. This requires that you have the following software/packages installed:

• wget
• autoconf
• automake
• libtool
• pkg-config
• gettext
• GNU make.

It is advisable to add --enable-maintainer-mode to the configure script. Thus:

$ ./autogen.sh
$ ./configure --enable-maintainer-mode
$ make
$ sudo make install

For later updates, you can use:

$ git pull
$ make
$ sudo make install

SSL/TLS Support

Dovecot uses OpenSSL for SSL/TLS support and it should be automatically detected. If it is not, you are missing some header files or libraries, or they are just in a non-standard path. Make sure you have the openssl-dev or a similar package installed, and if it is not in the standard location, set CPPFLAGS and LDFLAGS as shown in the first section above.

By default the SSL certificate is read from /etc/ssl/certs/dovecot.pem and the private key from /etc/ssl/private/dovecot.pem. The /etc/ssl directory can be changed using the --with-ssldir=DIR configure option. Both can of course be overridden from the configuration file.

You can use Mozilla SSL Configuration Generator to help create a default SSL configuration.

Optional Configure Options

Options are usually listed as --with-something or --enable-something. If you want to disable them, do it as --without-something or --disable-something. There are many default options that come from autoconf, automake or libtool. They are explained elsewhere.

Help Related Options

--help

Gives a full list of available options.

--help=short

List the dovecot specific options only and hide the generic configuration options.

Dovecot specific Options

Here is a list of options that Dovecot adds. You should not usually have to change these, these are usually not needed.

--enable-devel-checks

Enables some extra sanity checks. This is mainly useful for developers. It does quite a lot of unnecessary work but should catch some programming mistakes more quickly.

--enable-asserts

Enable assertion checks, enabled by default. Disabling them may slightly save some CPU, but if there are bugs they can cause more problems since they are not detected as early.

--without-shared-libs

Link Dovecot binaries with static libraries instead of dynamic libraries.

--disable-largefile

Specifies if we use 32bit or 64bit file offsets in 32bit CPUs. 64bit is the default if the system supports it (Linux and Solaris do). Dropping this to 32bit may save some memory, but it prevents accessing any file larger than 2 GB.

--with-mem-align=BYTES

Specifies memory alignment used for memory allocations. It is needed with many non-x86 systems and it should speed up x86 systems too. Default is 8, to make sure 64bit memory accessing works.

--with-ioloop=IOLOOP

Specifies what I/O loop method to use. Possibilities are select, poll, epoll and kqueue. The default is to use the best method available on your system.

--with-notify=NOTIFY

Specifies what file system notification method to use. Possibilities are dnotify, inotify (both on Linux), kqueue (FreeBSD) and none. The default is to use the best method available on your system.

Generic Features

--with-lua

Enables Lua support for authentication and push notifications.

FTS Options

--with-flatcurve

Flatcurve full text search (requires Xapian libraries).

--with-solr

Build with Solr full text search support

Compression Libraries

--with-zlib

Build with zlib compression support (default if detected)

--with-zstd

Build with zStandard compression support (default if detected)

SQL Driver Options

SQL drivers are typically used for authentication, and they may be used as a lib-dict backend too, which can be used by plugins for different purposes.

--with-cassandra

Build with cassandra support (requires cassandra-cpp-driver)

--with-pgsql

Build with PostgreSQL support (requires pgsql-devel, libpq-dev or similar package)

--with-mysql

Build with MySQL support (requires mysql-devel, libmysqlclient-dev or similar package)

--with-sqlite

Build with SQLite3 driver support (requires sqlite-devel, libsqlite3-dev or similar package)

Authentication Backend Options

The basic backends are built if the system is detected to support them:

--with-pam

Build with PAM authentication database support

--with-nss

Build with NSS authentication database support

--with-bsdauth

Build with BSD authentication database support

Authentication Backend Options (Extra Libraries Needed)

Some backends require extra libraries and are not necessarily wanted, so they are built only if specifically enabled:

--with-sql(=plugin)

Build with generic SQL support (drivers are enabled separately, see above). You can also build this as a plugin.

--with-ldap(=plugin)

Build with LDAP support (requires openldap-devel, libldap2-dev or similar package). You can also build this as a plugin.

--with-gssapi(=plugin)

Build with GSSAPI authentication support (requires krb5-devel, libkrb5-dev or similar package)

Dynamic IMAP and POP3 Modules

The mail_plugins setting lists all plugins that Dovecot is supposed to load from the mail_plugin_dir directory at program start. These plugins can do anything they want.

The plugin filename is prefixed with a number which specifies the order in which the plugins are loaded. This is important if one plugin depends on another.