Introduction

Cyrus is one of the most widely used IMAP/POP servers. Cyrus is apreciated for virtualisation of mailboxes and cool stuff like server side filtering (Sieve) or shared folders. It is frequently used in universities. In this howto, a basic installation of Cyrus with authentication on PAM will be explained.

Installation

Cyrus is in the main repository of Ubuntu (and as a consequence benefit from canonical security support). Install the following packages: cyrus-admin-2.2 cyrus-clients-2.2 cyrus-imapd-2.2 sasl2-bin (see InstallingSoftware). If you plan to support POP3 protocol install also cyrus-pop3d-2.2

If you do not have a MTA yet, this step will install postfix. Please refer to the Postfix page for details.

Configuration

Cyrus

Cyrus configuration is done in two configurations files: /etc/imapd.conf and /etc/cyrus.conf.

First, edit the /etc/cyrus.conf to activate the protocols you want. Here, imap and imaps will be activated:

8<----------------------------------------
SERVICES {
        # --- Normal cyrus spool, or Murder backends ---
        # add or remove based on preferences
        imap            cmd="imapd -U 30" listen="imap" prefork=0 maxchild=100
        imaps           cmd="imapd -s -U 30" listen="imaps" prefork=0 maxchild=100
        #pop3           cmd="pop3d -U 30" listen="pop3" prefork=0 maxchild=50
        #pop3s          cmd="pop3d -s -U 30" listen="pop3s" prefork=0 maxchild=50
8<----------------------------------------

You might need to update the location of the UNIX socket if using lmtp. At least in Ubuntu 8.04 the location is /var/run/cyrus/socket/lmtp. In postfix set accordingly.

Then edit /etc/imapd.conf (do not believe the name, it concerns general Cyrus stuff configuration). Only some parameters will be focused as most of options will match most of the needs.

8<----------------------------------------
# UNIX Hierarchy Convention
# Set to yes, and cyrus will accept dots in names, and use the forward
# slash "/" to delimit levels of the hierarchy. This is done by converting
# internally all dots to "^", and all "/" to dots. So the "rabbit.holes"
# mailbox of user "helmer.fudd" is stored in "user.elmer^fud.rabbit^holes"
unixhierarchysep: no
8<----------------------------------------

By default, unixhierarchysep if set to no which means that the separator is "." and not "/". You will have to turn in to yes if you want your mailbox to contains "." for example if you use mail addresses for naming your mailboxes.

8<----------------------------------------
# Uncomment the following and add the space-separated users who
# have admin rights for all services.
admins: cyrus
8<----------------------------------------

This parameter defines an administrator for all the services. It will be required for administration operations like mailbox creation.

8<----------------------------------------
# Do note that, since sasl will be run as user cyrus, you may have a lot of
# trouble to set this up right.
sasl_pwcheck_method: saslauthd
8<----------------------------------------

Indicates the method used for user authentication. saslauthd can also be used for Postfix authentication, as detailed in Postfix page.

8<----------------------------------------
# Force PLAIN/LOGIN authentication only
# (you need to uncomment this if you are not using an auxprop-based SASL
# mechanism.  saslauthd users, that means you!). And pay attention to
# sasl_minimum_layer and allowapop below, too.
sasl_mech_list: PLAIN
8<----------------------------------------

Last, change the /etc/default/saslauthd:

# This needs to be uncommented before saslauthd will be run automatically
START=yes

# You must specify the authentication mechanisms you wish to use.
# This defaults to "pam" for PAM support, but may also include
# "shadow" or "sasldb", like this:
MECHANISMS="pam"

Your authentication will be based on PAM. Probabily PAM is correctly setup on your machine.

Just launch saslauthd daemon:

# /etc/init.d/saslauthd start

Mail Transfer Agent

You have to configure your mail transfer agent to deliver your messages in your cyrus mailbox. In this howto, Postfix MTA will be presented. Feel free to add your favorite MTA.

Postfix

With Postfix, there are two ways of delivering messages in you mailbox: with a special transport named cyrus, or via lmtp (which is a protocol more or less similar to smtp). Choose the one you prefer. The cyrus transport is simple, lmtp is more powerful (i.e. you can communicate with lmtp between machines).

cyrus transport

In your postfix main.cf configuration file, add the following line:

mailbox_transport = cyrus

On Ubuntu installation, the transport cyrus is NOT already configured in /etc/postfix/master.cf. You must add manually at the end of master.cf the following lines:

# The Cyrus deliver program has changed incompatibly, multiple times.
cyrus     unix  -   n   n   -   -   pipe
  flags=R user=cyrus argv=/usr/sbin/cyrdeliver -e -m "${extension}" ${user}

lmtp

In your postfix main.cf configuration file, add the following line:

mailbox_transport = lmtp:unix:/var/run/lmtp

By default, on Ubuntu, the Unix socket lmtp is opened. Make sure the socket matches the socket specified in your /etc/cyrus.conf and /etc/imapd.conf.

In your postfix master.cf configuration file, edit the following line:

lmtp      unix  -       -       -       -       -       lmtp

to

lmtp      unix  -       -       n       -       -       lmtp

Otherwise, "No such file or directory" errors will be logged in the /var/log/mail.log as postfix tries to look for the socket in a chrooted environment.

Finally add postfix user to the mail group.

adduser postfix mail

Mailbox creation

First, you have define a "password" for the user admin for the cyrusadm. With root make this:

# saslpasswd2 -c cyrus
Password: TYPE YOUR CYRUS PASSWORD HERE
Again (for verification): RETYPE YOUR CYRUS PASSWORD

and:

# passwd cyrus
Enter new UNIX password: TYPE YOUR CYRUS PASSWORD HERE
Retype new UNIX password: RETYPE YOUR CYRUS PASSWORD

You also have to create the mailboxes for the users. User the cyradm utility for that:

cyradm --user cyrus localhost
IMAP Password:
localhost>

You can have the full description of the commands available by typing help. We will give more details in the section Administration & Maintenance.

Mailbox creation is done like this:

localhost>cm user.toto

Dot not forget the prefix user. or the mailbox created will be considered as a shared mailbox.

If you choose for unixhierarchysep: yes in /etc/imapd.conf the prefix must be user/

Test

Test that your installation works correctly:

# telnet localhost imap
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
* OK hostname Cyrus IMAP4 v2.1.18-IPv6-Debian-2.1.18-2ubuntu2 server ready
imap login user password
imap OK User logged in

Where user and password are your login and password on the server. If it does not work check /var/log/mail.log for evidence.

Administration / Maintenance

Links

Postfix Cyrus Web cyradm HOWTO


CategoryEmail CategoryNetworking

Cyrus (last edited 2012-05-04 12:30:36 by brie.aleida)