(install-dovecot)=
# Install and configure Dovecot

## Install Dovecot

To install a basic Dovecot server with common POP3 and IMAP functions, run the following command:

```bash
sudo apt install dovecot-imapd dovecot-pop3d
```

There are various other Dovecot modules including `dovecot-sieve` (mail filtering), `dovecot-solr` (full text search), `dovecot-antispam` (spam filter training), `dovecot-ldap` (user directory).

## Configure Dovecot

To configure Dovecot, edit the file `/etc/dovecot/dovecot.conf` and its included config files in `/etc/dovecot/conf.d/`. By default, all installed protocols will be enabled via an *include* directive in `/etc/dovecot/dovecot.conf`.

```text
!include_try /usr/share/dovecot/protocols.d/*.protocol
```

IMAPS and POP3S are more secure because they use SSL encryption to connect. A basic self-signed SSL certificate is automatically set up by package `ssl-cert` and used by Dovecot in `/etc/dovecot/conf.d/10-ssl.conf`.

`Mbox` format is configured by default, but you can also use `Maildir` if required. More details can be found in the comments in `/etc/dovecot/conf.d/10-mail.conf`. Also see [the Dovecot web site](https://doc.dovecot.org/admin_manual/mailbox_formats/) to learn about further benefits and details.

Make sure to also configure your chosen Mail Transport Agent (MTA) to transfer the incoming mail to the selected type of mailbox.

### Restart the Dovecot daemon

Once you have configured Dovecot, restart its daemon in order to test your setup using the following command:

```bash
sudo service dovecot restart
```

Try to log in with the commands `telnet localhost pop3` (for POP3) or `telnet localhost imap2` (for IMAP).  You should see something like the following:

```text
bhuvan@rainbow:~$ telnet localhost pop3
Trying 127.0.0.1...
Connected to localhost.localdomain.
Escape character is '^]'.
+OK Dovecot ready.
```

## Dovecot SSL configuration

By default, Dovecot is configured to use SSL automatically using the package `ssl-cert` which provides a self signed certificate.

You can instead generate your own custom certificate for Dovecot using `openssh`, for example:

```bash
sudo openssl req -new -x509 -days 1000 -nodes -out "/etc/dovecot/dovecot.pem" \
    -keyout "/etc/dovecot/private/dovecot.pem"
```

Next, edit `/etc/dovecot/conf.d/10-ssl.conf` and amend following lines to specify that Dovecot should use these custom certificates :

```text
ssl_cert = </etc/dovecot/private/dovecot.pem
ssl_key = </etc/dovecot/private/dovecot.key
```

You can get the SSL certificate from a Certificate Issuing Authority or you can create self-signed one. Once you create the certificate, you will have a key file and a certificate file that you want to make known in the config shown above.

> **Further reading**:
> For more details on creating custom certificates, see our guide on [security certificates](https://discourse.ubuntu.com/t/security-certificates/11885).

## Configure a firewall for an email server

To access your mail server from another computer, you must configure your firewall to allow connections to the server on the necessary ports.

  - IMAP - 143

  - IMAPS - 993

  - POP3 - 110

  - POP3S - 995

## References

- The [Dovecot website](http://www.dovecot.org/) has more general information about Dovecot.
- The [Dovecot manual](https://doc.dovecot.org) provides full documentation for Dovecot use.
- The [Dovecot Ubuntu Wiki](https://help.ubuntu.com/community/Dovecot) page has more details on configuration.