Dovecot and Postfix

Dovecot

Modoboa works better with Dovecot 2.0 so the following documentation is suitable for this combination.

In this section, we assume dovecot’s configuration resides in /etc/dovecot, all pathes will be relative to this directory.

Mailboxes

First, edit the conf.d/10-mail.conf and set the mail_location variable:

# maildir
mail_location = maildir:~/.maildir

Then, edit the inbox namespace and add the following lines:

mailbox Drafts {
  auto = create
  special_use = \Drafts
}
mailbox Junk {
  auto = create
  special_use = \Junk
}
mailbox Sent {
  auto = create
  special_use = \Sent
}
mailbox Trash {
  auto = create
  special_use = \Trash
}

It ensures all the special mailboxes will be automaticaly created for new accounts.

Operations on the file system

Three operation types are considered:

1. Mailbox creation
2. Mailbox renaming
3. Mailbox deletion

The first one is managed by Dovecot. The last two ones may be managed by Modoboa if it can access the file system where the mailboxes are stored (see General parameters to activate this feature).

Those operations are treated asynchronously by a cron script. For example, when you rename an e-mail address through the web UI, the associated mailbox on the file system is not modified directly. Instead of that, a rename order is created for this mailbox. The mailbox will be considered unavailable until the order is not executed (see Postfix configuration).

Edit the crontab of the user who owns the mailboxes on the file system:

$ crontab -u <user> -e

And add the following line inside:

* * * * * python <modoboa_site>/manage.py handle_mailbox_operations

Warning

The cron script must be executed by the system user owning the mailboxes.

Warning

The user running the cron script must have access to the settings.py file of the modoboa instance.

The result of each order is recorded into Modoboa’s log. Go to Modoboa > Logs to consult them.

Authentication

To make the authentication work, edit the conf.d/10-auth.conf and uncomment the following line at the end:

#!include auth-system.conf.ext
!include auth-sql.conf.ext
#!include auth-ldap.conf.ext
#!include auth-passwdfile.conf.ext
#!include auth-checkpassword.conf.ext
#!include auth-vpopmail.conf.ext
#!include auth-static.conf.ext

Then, edit the conf.d/auth-sql.conf.ext file and add the following content inside:

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

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

Make sure to activate only one backend (per type) inside your configuration (just comment the other ones).

Edit the dovecot-sql.conf.ext and modify the configuration according to your database engine.

MySQL users

driver = mysql

connect = host=<mysqld socket> dbname=<database> user=<user> password=<password>

default_pass_scheme = CRYPT

password_query = SELECT email AS user, password FROM admin_user WHERE email='%u' and is_active=1

user_query = SELECT '<mailboxes storage directory>/%d/%n' AS home, <uid> as uid, <gid> as gid, concat('*:bytes=', mb.quota, 'M') AS quota_rule FROM admin_mailbox mb INNER JOIN admin_domain dom ON mb.domain_id=dom.id WHERE mb.address='%n' AND dom.name='%d'

iterate_query = SELECT email AS username FROM admin_user

PostgreSQL users

driver = postgresql

connect = host=<postgres socket> dbname=<database> user=<user> password=<password>

default_pass_scheme = CRYPT

password_query = SELECT email AS user, password FROM admin_user WHERE email='%u' and is_active

user_query = SELECT '<mailboxes storage directory>/%d/%n' AS home, <uid> as uid, <gid> as gid, '*:bytes=' || mb.quota || 'M' AS quota_rule FROM admin_mailbox mb INNER JOIN admin_domain dom ON mb.domain_id=dom.id WHERE mb.address='%n' AND dom.name='%d'

iterate_query = SELECT email AS username FROM admin_user

SQLite users

driver = sqlite

connect = <path to the sqlite db file>

default_pass_scheme = CRYPT

password_query = SELECT email AS user, password FROM admin_user WHERE email='%u' and is_active=1

user_query = SELECT '<mailboxes storage directory>/%d/%n' AS home, <uid> as uid, <gid> as gid, ('*:bytes=' || mb.quota || 'M') AS quota_rule FROM admin_mailbox mb INNER JOIN admin_domain dom ON mb.domain_id=dom.id WHERE mb.address='%n' AND dom.name='%d'

iterate_query = SELECT email AS username FROM admin_user

Note

Replace values between <> with yours.

LDA

The LDA is activated by default but you must define a postmaster address. Open the conf.d/15-lda.conf file modify the following line:

postmaster_address = postmaster@<domain>

Quota

Modoboa lets adminstrators define per-domain and/or per-account limits (quota). It also lists the current quota usage of each account. Those features require Dovecot to be configured in a specific way.

Inside conf.d/10-mail.conf, add the quota plugin to the default activated ones:

mail_plugins = quota

Inside conf.d/10-master.conf, update the dict service to set proper permissions:

service dict {
  # If dict proxy is used, mail processes should have access to its socket.
  # For example: mode=0660, group=vmail and global mail_access_groups=vmail
  unix_listener dict {
    mode = 0600
    user = <user owning mailboxes>
    #group =
  }
}

Inside conf.d/20-imap.conf, activate the imap_quota plugin:

protocol imap {
  # ...

  mail_plugins = $mail_plugins imap_quota

  # ...
}

Inside dovecot.conf, activate the quota SQL dictionary backend:

dict {
  quota = <driver>:/etc/dovecot/dovecot-dict-sql.conf.ext
}

Inside conf.d/90-quota.conf, activate the quota dictionary backend:

plugin {
  quota = dict:User quota::proxy::quota
}

It will tell Dovecot to keep quota usage in the SQL dictionary.

Finally, edit the dovecot-dict-sql.conf.ext file and put the following content inside:

connect = host=<db host> dbname=<db name> user=<db user> password=<password>
# SQLite users
# connect = /path/to/the/database.db

map {
  pattern = priv/quota/storage
  table = admin_quota
  username_field = username
  value_field = bytes
}
map {
  pattern = priv/quota/messages
  table = admin_quota
  username_field = username
  value_field = messages
}

PostgreSQL users

Database schema update

The admin_quota table is created by Django but unfortunately it doesn’t support DEFAULT constraints (it only simulates them when the ORM is used). As PostgreSQL is a bit strict about constraint violations, you must execute the following query manually:

db=> ALTER TABLE admin_quota ALTER COLUMN bytes SET DEFAULT 0;
db=> ALTER TABLE admin_quota ALTER COLUMN messages SET DEFAULT 0;

Trigger

As indicated on Dovecot’s wiki, you need a trigger to properly update the quota. Unfortunately, the provided example won’t work for Modoboa. You should use the following one instead:

CREATE OR REPLACE FUNCTION merge_quota() RETURNS TRIGGER AS $$
BEGIN
  IF NEW.messages < 0 OR NEW.messages IS NULL THEN
    -- ugly kludge: we came here from this function, really do try to insert
    IF NEW.messages IS NULL THEN
      NEW.messages = 0;
    ELSE
      NEW.messages = -NEW.messages;
    END IF;
    return NEW;
  END IF;

  LOOP
    UPDATE admin_quota SET bytes = bytes + NEW.bytes,
      messages = messages + NEW.messages
      WHERE username = NEW.username;
    IF found THEN
      RETURN NULL;
    END IF;

    BEGIN
      IF NEW.messages = 0 THEN
        RETURN NEW;
      ELSE
        NEW.messages = - NEW.messages;
        return NEW;
      END IF;
    EXCEPTION WHEN unique_violation THEN
      -- someone just inserted the record, update it
    END;
  END LOOP;
END;
$$ LANGUAGE plpgsql;

CREATE OR REPLACE FUNCTION set_mboxid() RETURNS TRIGGER AS $$
DECLARE
  mboxid INTEGER;
BEGIN
  SELECT admin_mailbox.id INTO STRICT mboxid FROM admin_mailbox INNER JOIN admin_user ON admin_mailbox.user_id=admin_user.id WHERE admin_user.username=NEW.username;
  UPDATE admin_quota SET mbox_id = mboxid
    WHERE username = NEW.username;
  RETURN NULL;
END;
$$ LANGUAGE plpgsql;

DROP TRIGGER IF EXISTS mergequota ON admin_quota;
CREATE TRIGGER mergequota BEFORE INSERT ON admin_quota
   FOR EACH ROW EXECUTE PROCEDURE merge_quota();

DROP TRIGGER IF EXISTS setmboxid ON admin_quota;
CREATE TRIGGER setmboxid AFTER INSERT ON admin_quota
   FOR EACH ROW EXECUTE PROCEDURE set_mboxid();

Copy this example into a file (for example: quota-trigger.sql) on server running postgres and execute the following commands:

$ su - postgres
$ psql < /path/to/quota-trigger.sql
$ exit

Forcing recalculation

For existing installations, Dovecot (> 2) offers a command to recalculate the current quota usages. For example, if you want to update all usages, run the following command:

$ doveadm quota recalc -A

Be carefull, it can take a while to execute.

ManageSieve/Sieve

Modoboa lets users define filtering rules from the web interface. To do so, it requires ManageSieve to be activated on your server.

Inside conf.d/20-managesieve.conf, make sure the following lines are uncommented:

protocols = $protocols sieve

service managesieve-login {
  # ...
}

service managesieve {
  # ...
}

protocol sieve {
  # ...
}

Messages filtering using Sieve is done by the LDA.

Inside conf.d/15-lda.conf, activate the sieve plugin like this:

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

Finally, configure the sieve plugin by editing the conf.d/90-sieve.conf file. Put the follwing caontent inside:

plugin {
  # Location of the active script. When ManageSieve is used this is actually
  # a symlink pointing to the active script in the sieve storage directory.
  sieve = ~/.dovecot.sieve

  #
  # The path to the directory where the personal Sieve scripts are stored. For
  # ManageSieve this is where the uploaded scripts are stored.
  sieve_dir = ~/sieve
}

Restart Dovecot.

Postfix

This section gives an example about building a simple virtual hosting configuration with Postfix. Refer to the official documentation for more explanation.

Map files

You first need to create configuration files (or map files) that will be used by Postfix to lookup into Modoboa tables.

To automaticaly generate the requested map files and store them in a directory, run the following command:

$ modoboa-admin.py postfix_maps --dbtype <mysql|postgres|sqlite> mapfiles

mapfiles is the directory where the files will be stored. Answer the few questions and you’re done.

Configuration

Use the following configuration in the /etc/postfix/main.cf file (this is just one possible configuration):

# Stuff before
virtual_transport = dovecot
dovecot_destination_recipient_limit = 1

virtual_minimum_uid = <vmail user id>
virtual_gid_maps = static:<vmail group id>
virtual_uid_maps = static:<vmail user id>
virtual_mailbox_base = /var/vmail

relay_domains =
virtual_mailbox_domains = <driver>:/etc/postfix/sql-domains.cf
virtual_alias_domains = <driver>:/etc/postfix/sql-domain-aliases.cf
virtual_mailbox_maps = <driver>:/etc/postfix/sql-mailboxes.cf
virtual_alias_maps = <driver>:/etc/postfix/sql-aliases.cf,
      <driver>:/etc/postfix/sql-domain-aliases-mailboxes.cf,
      <driver>:/etc/postfix/sql-email2email.cf,
      <driver>:/etc/postfix/sql-catchall-aliases.cf

smtpd_recipient_restrictions =
      ...
      check_recipient_access <driver>:/etc/postfix/maps/sql-maintain.cf
      permit_mynetworks
      ...

# Stuff after

Replace <driver> by the name of the database you use.

Then, edit the /etc/postfix/master.cf file and add the following definition at the end:

dovecot   unix  -       n       n       -       -       pipe
  flags=DRhu user=vmail:vmail argv=/usr/lib/dovecot/deliver -f ${sender} -d ${recipient}

Restart Postfix.