This page explains installation and configuration of dovecot 2 as shipped with Ubuntu 12.04LTS. For the installation of dovecot 1.2, e. g. on Ubuntu 10.04LTS, please check this page.

Dovecot IMAP, POP3, and Sieve services along with MySQL support are installed using the following command.

sudo aptitude install dovecot-imapd dovecot-pop3d dovecot-sieve dovecot-mysql dovecot-managesieved

In contrast to Dovecot version 1.2, where most configuration was done in the file /etc/dovecot/dovecot.conf, the configuration of version 2 is distributed over several files with dedicated purpose, located under /etc/dovecot/conf.d. I will step through the required changes by each necessary file in the following paragraphs.

Authorization using MySQL

The authorization settings are configured in 10-auth.conf. I almost left everything as is, just added the following line to the include section at the very end of the file

!include auth-sql.conf.ext

This tells dovecot to include the file auth-sql.conf.ext, which has yet to be created. Therefore, add the following lines to the file /etc/dovecot/conf.d/auth-sql-conf.ext:

passdb {
  driver = sql 

  # Path for SQL configuration file, see example-config/dovecot-sql.conf.ext
  args = /etc/dovecot/dovecot-sql.conf.ext
}

userdb {
  driver = sql 
  args = /etc/dovecot/dovecot-sql.conf.ext
}

Now make sure to have the following settings within the file /etc/dovecot/dovecot-sql.conf.ext:

driver = mysql
connect = host=127.0.0.1 port=3306 user=mailuser password=mailuserpassword dbname=mailserver

# depends on postfixadmin config
default_pass_scheme = MD5-CRYPT

# taken from postfixadmin docs
password_query = SELECT username as user, password, concat('/var/spool/postfix/virtual/', maildir) as userdb_home, concat('maildir:/var/spool/postfix/virtual/', maildir) as userdb_mail, 118 as userdb_uid, 8 as userdb_gid FROM mailbox WHERE username = '%u' AND active = '1'

# taken from postfixadmin docs
user_query = SELECT concat('/var/spool/postfix/virtual/', maildir) as home, concat('maildir:/var/spool/postfix/virtual/',maildir) as mail, 118 AS uid, 8 AS gid FROM mailbox WHERE username = '%u' AND active='1'

Set the First Valid UID

This is really a quick one: Just open the file /etc/dovecot/conf.d/10-mail.conf and make sure to set the first_valid_uid to the UID of your mail user. Mine is 113 - and make sure to set the authentication socket path:

first_valid_uid = 113
auth_socket_path = /var/run/dovecot/auth-userdb

Configure the Mail Service

Now add your user names, groups to the file /etc/dovecot/conf.d/10-master.conf. I have added the following contents (with a little context):

service auth {
  # auth_socket_path points to this userdb socket by default. It's typically
  # used by dovecot-lda, doveadm, possibly imap process, etc. Its default
  # permissions make it readable only by root, but you may need to relax these
  # permissions. Users that have access to this socket are able to get a list
  # of all usernames and get results of everyone's userdb lookups.
  unix_listener auth-userdb {
    #mode = 0600
    user = vmail
    group = mail
  }

  # Postfix smtp-auth
  unix_listener /var/spool/postfix/private/auth {
    mode = 0666
    user = postfix
    group = postfix
  }

  # Auth process is run as this user.
  #user = $default_internal_user
}

SSL Configuration

If you provide SSL support, which I would highly recommend, you can add your key, vert and the certification authority to the file /etc/dovecot/conf.d/10-ssl.conf:

# SSL/TLS support: yes, no, required. <doc/wiki/SSL.txt>
ssl = yes 

# PEM encoded X.509 SSL/TLS certificate and private key. They're opened before
# dropping root privileges, so keep the key file unreadable by anyone but
# root. Included doc/mkcert.sh can be used to easily generate self-signed
# certificate, just make sure to update the domains in dovecot-openssl.cnf
ssl_cert = </etc/ssl/certs/nesono.crt
ssl_key = </etc/ssl/private/nesono.key
ssl_ca = </etc/ssl/private/ca.pem

Configure the Local Delivery Agent (LDA)

I simply added the postmaster address and hostname to the file /etc/dovecot/conf.d/15-lda.conf as well as added sieve as a mail plugin, which is the whole reason why I am using Dovecot LDA at all:

#postmaster_address =
postmaster_address = postmaster@nesono.com

# Hostname to use in various parts of sent mails, eg. in Message-Id.
# Default is the system's real hostname.
hostname = nesono.com

protocol lda {
  # Space separated list of plugins to load (default is global mail_plugins).
  #mail_plugins = $mail_plugins
  mail_plugins = $mail_plugins sieve
}

Additionally, you have to tell postfix to forward the local delivery dovecot. You do this by modifying the following lines in your /etc/postfix/main.cf:

mailbox_command = /usr/lib/dovecot/deliver
mailbox_transport = dovecot

Sieve Configuration

In the file /etc/dovecot/conf.d/90-sieve.conf I have the following lines uncommented:

plugin {
  # The path to the user's main active script. If ManageSieve is used, this the
  # location of the symbolic link controlled by ManageSieve.
  sieve = ~/.dovecot.sieve

  # Directory for :personal include scripts for the include extension. This
  # is also where the ManageSieve service stores the user's scripts.
  sieve_dir = ~/sieve
}

Fine

One final note: To configure sieve, you can use roundcube, which no longer seems to have the file size limitation of the sieve script, which drove me up the wall in the days of roundcube version 0.5.

Now restart dovecot, reload postfix and check your mail!

Cheers, iss.