Running a basic server

Once you have compiled and installed Cyrus, you can configure your environment and start Cyrus.

At the end of this guide, you will be up and running with a local instance of Cyrus. It will have with basic incoming and outgoing mail flow, with CalDAV and CardDAV support.

Note

These instructions are for Debian “Jessie” or newer. For other operating systems or distros, dependency names in package managers may differ, but the main concepts remain the same.

Please note that this guide is meant to get you a working environment quickly, not to allow you to customize everything.

This guide will set up Cyrus to work with the Sendmail SMTP server - and there will be no instructions for using Postfix. Once you have a working environment, you are welcome to experiment further and set up a different MTA or use different kinds of authentication schemes, etc.

1. Update your system

First update the system to ensure everything is current. This may take some time; you can check Hacker News in the meantime.

sudo apt-get update
sudo apt-get upgrade -y

2. Install Cyrus 3rd party dependencies

Install libraries and tools used by Cyrus IMAP. This includes a C compiler, build tools, and some support libraries. Just like the previous command, this one may take a few minutes to complete.

As well as all of the things needed for building Cyrus itself, we’ll also install some packages needed to support Cassandane – the automated test facility.

sudo apt-get install -y autoconf automake autotools-dev bash-completion bison build-essential comerr-dev \
    debhelper flex g++ git gperf groff heimdal-dev libbsd-resource-perl libclone-perl libconfig-inifiles-perl \
    libcunit1-dev libdatetime-perl libdb-dev libdigest-sha-perl libencode-imaputf7-perl libfile-chdir-perl \
    libglib2.0-dev libical-dev libio-socket-inet6-perl libio-stringy-perl libjansson-dev libldap2-dev \
    libmysqlclient-dev libnet-server-perl libnews-nntpclient-perl libpam0g-dev libpcre3-dev libsasl2-dev \
    libsnmp-dev libsqlite3-dev libssl-dev libtest-unit-perl libtool libunix-syslog-perl liburi-perl \
    libxapian-dev libxml-generator-perl libxml-xpath-perl libxml2-dev libwrap0-dev libzephyr-dev lsb-base \
    net-tools perl php5-cli php5-curl pkg-config po-debconf tcl-dev \
    transfig uuid-dev vim wamerican wget xutils-dev zlib1g-dev sasl2-bin rsyslog sudo acl telnet

3. Setup the cyrus:mail user and group

Now let’s create a special user account just for the Cyrus server to sandbox Cyrus: called cyrus. We’ll also create a mail group as well. This allows Cyrus to give other programs some permissions if they are run under the mail group, again, without causing a Cyrus bug to delete all of your cat pictures. Disaster!

If you have installed from packages, your package vendor may have already done this for you. To check, use these commands:

getent group mail
mail:x:8:
getent passwd cyrus
cyrus:x:999:8:Cyrus IMAP Server:/var/lib/imap:/bin/bash

Example group and user creation commands for GNU/Linux:

groupadd -fr mail
useradd -c "Cyrus IMAP Server" -d /var/lib/imap -g mail -s /bin/bash -r cyrus

If your installation will use system locations for things like SSL certificates (i.e. /etc/ssl/certs /etc/ssl/private), then you should also add the cyrus user to the appropriate group to gain access to the PKI files. On Debian/Ubuntu systems, for example, this group is ssl-cert:

usermod -aG ssl-cert cyrus

4. Setting up authentication with SASL

Now, let’s set up SASL. This will allow you to connect to your local IMAP server and login, just like any IMAP user would before checking for new emails.

Create a saslauth group and add the cyrus user to the group, so Cyrus can access SASL. (on Debian, this group is called ‘sasl’: adjust the following commands to suit.)

groupadd -fr saslauth
usermod -aG saslauth cyrus
Change the default SASL configuration in /etc/default/saslauthd.
  1. Make sure that the START option is set to yes (START=yes) and
  2. Set the``MECHANISMS`` option to sasldb (MECHANISMS="sasldb").

Start the SASL auth daemon:

/etc/init.d/saslauthd start

Now, we’ll create the IMAP user inside SASL. This is the user you’ll use to login to the IMAP server later on.

echo 'secret' | saslpasswd2 -p -c imapuser

You can replace secret with a more suitable password you want and imapuser with the username you want. Once this is done, check that the user exists and is set up correctly:

testsaslauthd -u imapuser -p secret

You should get an 0: OK "Success." message.

5. Setup mail delivery from your MTA

Your Cyrus IMAP server will want to receive the emails accepted by your SMTP server (ie Sendmail, Postfix, etc). In Cyrus, this happens via a protocol called LMTP, which is usually supported by your SMTP server.

Install Sendmail

We’ll set up LMTP with the Sendmail SMTP server.

sudo apt-get install -y sendmail

We need to make Sendmail aware of the fact we are using the Cyrus IMAP server: modify the /etc/mail/sendmail.mc file. Add this line before the MAILER_DEFINITIONS section:

define(`confLOCAL_MAILER', `cyrusv2')dnl

And right below MAILER_DEFINITIONS, add this:

MAILER(`cyrusv2')dnl

This enables the cyrusv2 mailer for local mail delivery. This is a sendmail property that tells sendmail it’s talking to Cyrus. (Cyrus 3.x works with this property, despite the naming confusion.)

Next, we run a script that takes the /etc/mail/sendmail.mc file and and prepares it for use by Sendmail. This may take some time.

sudo sendmailconfig

Sendmail communication

One last thing we need to do for LMTP to work with Sendmail is to create a folder that will contain the UNIX socket used by Sendmail and Cyrus to deliver/receive emails:

sudo mkdir -p /var/run/cyrus/socket
sudo chown cyrus:mail /var/run/cyrus/socket
sudo chmod 750 /var/run/cyrus/socket

6. Protocol ports

The Cyrus IMAP server provides service interfaces via either TCP/IP ports or Unix domain sockets. For the former, Cyrus requires that there are proper entries in the host’s /etc/services file. The following are required for any host using the listed services:

pop3      110/tcp  # Post Office Protocol v3
nntp      119/tcp  # Network News Transport Protocol
imap      143/tcp  # Internet Mail Access Protocol rev4
imsp      406/tcp  # Internet Message Support Protocol (deprecated)
nntps     563/tcp  # NNTP over TLS
imaps     993/tcp  # IMAP over TLS
pop3s     995/tcp  # POP3 over TLS
kpop      1109/tcp # Kerberized Post Office Protocol
lmtp      2003/tcp # Lightweight Mail Transport Protocol service
smmap     2004/tcp # Cyrus smmapd (quota check) service
csync     2005/tcp # Cyrus replication service
mupdate   3905/tcp # Cyrus mupdate service
sieve     4190/tcp # timsieved Sieve Mail Filtering Language service

Make sure that these lines are present and add them if they are missing.

7. Configuring Cyrus

(Nearly there)

Set up a simple directory structure for Cyrus to store emails, owned by the cyrus user and group mail:

sudo mkdir -p /var/lib/cyrus /var/spool/cyrus
sudo chown -R cyrus:mail /var/lib/cyrus /var/spool/imap
sudo chmod 750 /var/lib/cyrus /var/spool/cyrus

Let’s add some basic configuration for the Cyrus IMAP server. Two files have to be added: /etc/imapd.conf and /etc/cyrus.conf. There are several examples included with the software, in doc/examples/. Pick one each from the imapd_conf and cyrus_conf directories, or create your own.

For imapd.conf(5), let’s start with the normal.conf example:

# Suggested minimal imapd.conf
# See imapd.conf(5) for more information and more options

# Space-separated users who have admin rights for all services.
# NB: THIS MUST BE CONFIGURED
admins: cyrus

###################################################################
## File, socket and DB location settings.
###################################################################

# Configuration directory
configdirectory: /var/lib/cyrus

# Directories for proc and lock files
proc_path: /run/cyrus/proc
mboxname_lockpath: /run/cyrus/lock

# Locations for DB files
# The following DB are recreated upon initialization, so should live in
# ephemeral storage for best performance.
duplicate_db_path: /run/cyrus/deliver.db
ptscache_db_path:  /run/cyrus/ptscache.db
statuscache_db_path: /run/cyrus/statuscache.db
tls_sessions_db_path: /run/cyrus/tls_sessions.db

# Which partition to use for default mailboxes
defaultpartition: default
partition-default: /var/spool/cyrus/mail

# If sieveusehomedir is false (the default), this directory is searched
# for Sieve scripts.
sievedir: /var/spool/sieve

###################################################################
## Important: KEEP THESE IN SYNC WITH cyrus.conf
###################################################################

lmtpsocket: /run/cyrus/socket/lmtp
idlesocket: /run/cyrus/socket/idle
notifysocket: /run/cyrus/socket/notify

# Syslog prefix. Defaults to cyrus (so logging is done as cyrus/imap
# etc.)
syslog_prefix: cyrus

###################################################################
## Server behaviour settings
###################################################################

# Space-separated list of HTTP modules that will be enabled in
# httpd(8).  This option has no effect on modules that are disabled at
# compile time due to missing dependencies (e.g. libical).
# 
# Allowed values: caldav, carddav, domainkey, ischedule, rss
httpmodules: caldav carddav

# If enabled, the partitions will also be hashed, in addition to the
# hashing done on configuration directories. This is recommended if one
# partition has a very bushy mailbox tree.
hashimapspool: true

###################################################################
## User experience settings
###################################################################

# Minimum time between POP mail fetches in minutes
popminpoll: 1

###################################################################
## User Authentication settings
###################################################################

# Allow plaintext logins by default (SASL PLAIN)
allowplaintext: yes

###################################################################
## SASL library options (these are handled directly by the SASL
## libraries, refer to SASL documentation for an up-to-date list of
## these)
###################################################################

# The mechanism(s) used by the server to verify plaintext passwords.
# Possible values are "saslauthd", "auxprop", "pwcheck" and
# "alwaystrue".  They are tried in order, you can specify more than one,
# separated by spaces.
sasl_pwcheck_method: saslauthd

# If enabled, the SASL library will automatically create authentication
# secrets when given a plaintext password. Refer to SASL documentation 
sasl_auto_transition: no

###################################################################
## SSL/TLS Options
###################################################################

# File containing the global certificate used for ALL services (imap,
# pop3, lmtp, sieve)
#tls_server_cert: /etc/ssl/certs/ssl-cert-snakeoil.pem

# File containing the private key belonging to the global server
# certificate.
#tls_server_key: /etc/ssl/private/ssl-cert-snakeoil.key


# File containing one or more Certificate Authority (CA) certificates.
#tls_client_ca_file: /etc/ssl/certs/cyrus-imapd-ca.pem

# Path to directory with certificates of CAs.
tls_client_ca_dir: /etc/ssl/certs

# The length of time (in minutes) that a TLS session will be cached for
# later reuse.  The maximum value is 1440 (24 hours), the default.  A
# value of 0 will disable session caching.
tls_session_timeout: 1440

Note that configdirectory and partition-default are set to the folders we just created.

The admin user is the imapuser created in step 4, for authentication against sasl. Change this value if you named your user something different.

For cyrus.conf(5), again we’ll start with the normal.conf example:

# standard standalone server implementation

START {
  # do not delete this entry!
  recover       cmd="ctl_cyrusdb -r"
}

# UNIX sockets start with a slash and are put into /var/imap/socket
SERVICES {
  # add or remove based on preferences
  imap          cmd="imapd" listen="imap" prefork=0
  imaps         cmd="imapd -s" listen="imaps" prefork=0
  pop3          cmd="pop3d" listen="pop3" prefork=0
  pop3s         cmd="pop3d -s" listen="pop3s" prefork=0
  sieve         cmd="timsieved" listen="sieve" prefork=0

  # these are only necessary if receiving/exporting usenet via NNTP
#  nntp          cmd="nntpd" listen="nntp" prefork=0
#  nntps         cmd="nntpd -s" listen="nntps" prefork=0

  # these are only necessary if using HTTP for CalDAV, CardDAV, or RSS
  http          cmd="httpd" listen="http" prefork=0
  https         cmd="httpd -s" listen="https" prefork=0

  # at least one LMTP is required for delivery
#  lmtp          cmd="lmtpd" listen="lmtp" prefork=0
  lmtpunix      cmd="lmtpd" listen="/var/imap/socket/lmtp" prefork=0

  # this is required if using notifications
#  notify        cmd="notifyd" listen="/var/imap/socket/notify" proto="udp" prefork=1
}

EVENTS {
  # this is required
  checkpoint    cmd="ctl_cyrusdb -c" period=30

  # this is only necessary if using duplicate delivery suppression,
  # Sieve or NNTP
  delprune      cmd="cyr_expire -E 3" at=0400

  # Expire data older than 28 days.
  deleteprune   cmd="cyr_expire -E 4 -D 28" at=0430
  expungeprune  cmd="cyr_expire -E 4 -X 28" at=0445

  # this is only necessary if caching TLS sessions
  tlsprune      cmd="tls_prune" at=0400
}

DAEMON {
  # this is only necessary if using idled for IMAP IDLE
#  idled         cmd="idled"
}

Before you launch Cyrus for the first time, create the Cyrus directory structure: use mkimap(8).

sudo -u cyrus ./tools/mkimap

8. Launch Cyrus

sudo ./master/master -d

Check /var/log/syslog for errors so you can quickly understand any problems.

When you’re ready, you can create init scripts to start and stop your daemons. This https://www.linux.com/learn/managing-linux-daemons-init-scripts is old, but has a good explanation of the concepts required.

Optional: Setting up SSL certificates

Create a TLS certificate using OpenSSL. Generate the certificate and store it in the /var/lib/cyrus/server.pem file:

sudo openssl req -new -x509 -nodes -out /var/lib/cyrus/server.pem \
-keyout /var/lib/cyrus/server.pem -days 365 \
-subj "/C=US/ST=Denial/L=Springfield/O=Dis/CN=localhost"

This creates a TLS certificate (-out) and private key (-keyout) in the X.509 format (-x509). The certificate is set to expire in 365 days (-days) and has default information set up (-subj ...). The contents of the -subj is non-trivial and defined in RFC 5280, a brief summary is available on stackoverflow which is enough to decode our sample above.

Great! You should now have a file at /var/lib/cyrus/server.pem. Give Cyrus access to this file:

sudo chown cyrus:mail /var/lib/cyrus/server.pem

Awesome! Almost done. We will now configure the Cyrus IMAP server to actually use this TLS certificate. Open your Cyrus configuration file /etc/imapd.conf and add the following to lines at the end of it:

tls_server_cert: /var/lib/cyrus/server.pem
tls_server_key: /var/lib/cyrus/server.pem

This tells the server where to find the TLS certificate and the key. It may seem weird to specify the same file twice, but since the file has the x509 format, the server will know what to do. Cyrus is there for you, always (unless your hard drive burns down) ! :-)

The other configuration file we have to edit is /etc/cyrus.conf. Open it up with your favorite text editor and in the SERVICES section, add (or uncomment) this line:

imaps        cmd="imapd" listen="imaps" prefork=0

Notice the s at the end of imaps. This says we are using TLS. Similar such lines may be used for pop3s, lmtps and other protocols. See Protocol Ports, above, for more information on these.

If you now restart (or start) your Cyrus server, you should have Cyrus listening on port 993 (the IMAPS port) with the STARTTLS IMAP extension enabled. You can check that TLS works as expected with the following command:

imtest -t "" -u imapuser -a imapuser -w secret localhost

Make sure to replace imapuser with whatever user you set up with saslpasswd2 before, and to replace secret with the actual password you set for that user.

Sending a test email

We will send a test email to our local development environment to check if:

  • The SMTP server* accepts the incoming email,
  • LMTP transmits the email to Cyrus IMAP,
  • You can see the email stored on your filesystem.

Note

*SMTP servers also often called an “MTA,” for Mail Transport Agent

But first, create a mailbox to send the test email to. We’ll call this test mailbox example@localhost.

echo 'createmailbox user/example@localhost' | cyradm -u imapuser -w secret localhost

We seem to be creating a mailbox named user/example@localhost. In fact, Cyrus understands this to be a user called example@localhost. As usual, adjust the password via the -w option to the password you set above.

If you have explicitly disabled unixhierarchysep in /etc/imapd.conf (it is enabled by default in 3.0+), you should replace user/example@localhost with user.example@localhost. You can read more about unixhierarchysep in imapd.conf(5).

The command will produce the following output:

localhost> localhost>

This happens because cyradm is normally used interactively, with a prompt. We aren’t using a prompt, so this output is expected.

Now that the mailbox exists, we can send an email using telnet with raw SMTP commands.

First, connect to the MTA:

telnet localhost smtp

You should see a prompt appear:

Trying ::1...
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
220 ... ESMTP Sendmail ...

Now, we’ll send the SMTP commands to the server. These are responsible for ordering the MTA to store an email:

EHLO localhost
MAIL FROM:<hello@localhost>
RCPT TO:<example@localhost>
DATA
Hello world!
.
QUIT

If you are using Sendmail as your SMTP server, you should be able to safely copy and paste this bit into the terminal before hitting your ENTER key. If not, you may want to paste these commands one by one (or make sure you enable PIPELINING in the SMTP config).

If you see a message like 250 2.0.0 ... Message accepted for delivery, you did it! You should now have a file called 1. in the /var/spool/cyrus/user/example directory, with the content of the email you sent just before.

If not, you may want to check syslog to see if any error messages show up and go through the previous steps again.

To let the example user log in via IMAP on a normal mail client, you need to add them to SASL (as before):

echo 'mypassword' | saslpasswd2 -p -c example

Check your two users are there:

sasldblistusers2

You can now configure a mail client to access your new mailserver and connect to the mailbox for example@localhost via IMAP and see the message.

Checking CardDAV and CardDAV

Modify /etc/cyrus.conf and add (or uncomment) this line in the SERVICES section:

http        cmd="httpd" listen="http" prefork=0

Modify /etc/imapd.conf and add (or uncomment) this line:

httpmodules: caldav carddav

Running the following commands should return you sample entry addressbook and calendar entry for the sample example user:

curl -u example@[hostname]:mypassword -i -X PROPFIND -H 'Depth: 1' http://localhost:8080/dav/addressbooks/user/example@[hostname]/Default

curl -u example@[hostname]:mypassword -i -X PROPFIND -H 'Depth: 1' http://localhost:8080/dav/principals/user/example@[hostname]/

Troubleshooting

Some common issues are explained below.

I have all kinds of weird Perl errors when running cyradm

The solution is to set the Perl library path right. To be honest, I was too lazy to figure out exactly which path was right, so I added this snippet to my ~/.bashrc file:

export PERL5LIB="$PERL5LIB:$(find path/to/cyrus/perl -type d | tr "\\n" ":")"

Just make sure to change path/to/cyrus to the actual path to the Cyrus source code directory. This should be something like /home/jack/cyrus-src/perl.

I can’t connect to the IMAP server

Make sure that the SASL auth daemon is running. You can start it with this command:

/etc/init.d/saslauthd start

You can safely run this command even if you don’t know whether the SASL auth daemon is already running or not.

Emails are not being delivered to Cyrus

Make sure that you have started Sendmail, which you can do like this:

/etc/init.d/sendmail start

My IMAP server (master) can’t authenticate users to SASL

Check that the groups setting on your cyrus user is correct.

Ubuntu uses saslauth group, Debian uses sasl group.

Check the output of groups cyrus to see what groups it currently belongs to.

Incorrect groups settings results in saslauthd reporting permission failures:

SASL cannot connect to saslauthd server: Permission denied
SASL unable to open Berkeley db /etc/sasldb2: Permission denied

Master will need to be restarted if you needed to change the groups.

Something is not working but I can’t figure out why

More information is almost always logged to syslog. Make sure you start syslog with this command before starting the Cyrus server:

/etc/init.d/rsyslog start

My question isn’t answered here

Join us in the #cyrus IRC channel on Freenode or on the mailing lists if you need help or just want to chat about Cyrus, IMAP, donuts, etc.