ejabberd 2.0.0b1
 
Installation and Operation Guide





















ejabberd Development Team


Contents

Chapter 1  Introduction

ejabberd is a free and open source instant messaging server written in Erlang.

ejabberd is cross-platform, distributed, fault-tolerant, and based on open standards to achieve real-time communication.

ejabberd is designed to be a rock-solid and feature rich XMPP server.

ejabberd is suitable for small deployments, whether they need to be scalable or not, as well as extremely big deployments.

1.1  Key Features

ejabberd is:

1.2  Additional Features

Moreover, ejabberd comes with a wide range of other state-of-the-art features:

Chapter 2  Installing ejabberd

2.1  Installing ejabberd with Graphical Installer

The easiest approach to install an ejabberd Instant Messaging server is to use the graphical installer. The installer is available in ejabberd Process-one downloads page.

The installer will deploy and configure a full featured ejabberd server and does not require any extra dependencies.

2.2  Installing ejabberd with Operating System specific packages

Some Operating Systems provide a specific ejabberd package adapted to your system architecture and libraries, which also checks dependencies and performs basic configuration tasks like creating the initial administrator account. Some examples are Debian and Gentoo. Consult the resources provided by your Operating System for more information.

2.3  Installing ejabberd with CEAN

CEAN (Comprehensive Erlang Archive Network) is a repository that hosts binary packages from many Erlang programs, including ejabberd and all its dependencies. The binaries are available for many different system architectures, so this is an alternative to the binary installer and Operating System's ejabberd packages.

2.4  Installing ejabberd from Source Code

2.4.1  Requirements

To compile ejabberd on a `Unix-like' operating system, you need:

2.4.2  Download Source Sode

Released versions of ejabberd can be obtained from
http://www.process-one.net/en/ejabberd/downloads

The latest development version can be retrieved from the Subversion repository using this command: 
  svn co http://svn.process-one.net/ejabberd/trunk ejabberd

2.4.3  Compile

To compile ejabberd execute the commands: 
  ./configure
  make
The compilation process may report several warnings related to unusued variables. This is common, and is not a problem.

The build configuration script provides several parameters. To get the full list run the command: 
  ./configure --help
Some options that you may be interested in modifying:
–prefix=/
Specify the path prefix where the files will be copied when running the make install command.

–enable-pam
Enable the PAM authentication method.

–enable-odbc or –enable-mssql
Required if you want to use an external database. See section 3.2 for more information.

–enable-full-xml
Enable the use of XML based optimisations. It will for example use CDATA to escape characters in the XMPP stream. Use this option only if you are sure your Jabber clients include a fully compliant XML parser.

–disable-transient-supervisors
Disable the use of Erlang/OTP supervision for transient processes.

2.4.4  Install

To install ejabberd in the destination directories, run the command: 
  make install
Note that you may need to have administrative privileges in the system.

The files and directories created are, by default:
/etc/ejabberd/
Configuration files:
ejabberd.cfg
ejabberd configuration file
ejabberd.inetrc
Network DNS configuration
ejabberdctl.cfg
Configuration file of the administration script
/sbin/ejabberdctl
Administration script
/var/lib/ejabberd/
.erlang.cookie
Erlang cookie file
db
Database spool files
ebin
Binary Erlang files (*.beam)
priv
lib
Binary system libraries (*.so)
msgs
Translated strings (*.msgs)
/var/log/ejabberd/
Log files:
ejabberd.log
Messages reported by ejabberd code
sasl.log
Messages reported by Erlang/OTP

2.4.5  Start

You can use the ejabberdctl command line administration script to start and stop ejabberd. Please refer to the section 4.1.2 for details about ejabberdctl.

The command line parameters used by the ejabberdctl administration script when starting the Erlang/OTP virtual machine are:
-pa /var/lib/ejabberd/ebin
Specify the directory where Erlang binary files (*.beam) are located.
-sname ejabberd
The Erlang node will be identified using only the first part of the host name, i. e. other Erlang nodes outside this domain cannot contact this node. This is the preferable option in most cases.
-name ejabberd
The Erlang node will be fully identified. This is only useful if you plan to setup an ejabberd cluster with nodes in different networks.
-s ejabberd
This paramaters tells the Erlang machine to start the ejabberd application
-mnesia dir "/var/lib/ejabberd/spool"
Specify the Mnesia database directory.
-ejabberd config "/etc/ejabberd/ejabberd.cfg"
Specify the ejabberd configuration file.
-ejabberd log_path "/var/log/ejabberd/ejabberd.log"
Specify the directory for the ejabberd.log file.
-sasl sasl_error_logger {file, "/var/log/ejabberd/sasl.log"}
Specify the directory for the sasl.log file.
-env ERL_MAX_PORTS=32000
Allow up to 32000 connections. The default limit is just 1024. With this value, ejabberd will use more memory (approximately 6 MB more).
-env ERL_FULLSWEEP_AFTER=0
May reduce memory usage, but ejabberd may consume more processor.
Note that some characters need to be escaped when used in shell scripts, for instance " and {}.

You can find other options in the Erlang manual page (erl -man erl).

2.4.6  Specific Notes for BSD

The command to compile ejabberd in BSD systems is: 
  gmake

2.4.7  Specific Notes for Microsoft Windows

Requirements

To compile ejabberd on a Microsoft Windows system, you need:

Compilation

We assume that we will try to put as much library as possible into C:\sdk\ to make it easier to track what is install for ejabberd.
  1. Install Erlang emulator (for example, into C:\sdk\erl5.5.5).
  2. Install Expat library into C:\sdk\Expat-2.0.0 directory.

    Copy file C:\sdk\Expat-2.0.0\Libs\libexpat.dll to your Windows system directory (for example, C:\WINNT or C:\WINNT\System32)
  3. Build and install the Iconv library into the directory C:\sdk\GnuWin32.

    Copy file C:\sdk\GnuWin32\bin\lib*.dll to your Windows system directory (more installation instructions can be found in the file README.woe32 in the iconv distribution).

    Note: instead of copying libexpat.dll and iconv.dll to the Windows directory, you can add the directories C:\sdk\Expat-2.0.0\Libs and C:\sdk\GnuWin32\bin to the PATH environment variable.
  4. Install OpenSSL in C:\sdk\OpenSSL and add C:\sdk\OpenSSL\lib\VC to your path or copy the binaries to your system directory.
  5. Install ZLib in C:\sdk\gnuWin32. Copy C:\sdk\GnuWin32\bin\zlib1.dll to your system directory. If you change your path it should already be set after libiconv install.
  6. Make sure the you can access Erlang binaries from your path. For example: set PATH=%PATH%;"C:\sdk\erl5.5.5\bin"
  7. Depending on how you end up actually installing the library you might need to check and tweak the paths in the file configure.erl.
  8. While in the directory ejabberd\src run: 
    configure.bat
nmake -f Makefile.win32
  9. Edit the file ejabberd\src\ejabberd.cfg and run 
    werl -s ejabberd -name ejabberd

2.5  Creating an Initial Administrator

Before the web interface can be entered to perform administration tasks, an account with administrator rights is needed on your ejabberd deployment.

Instructions to create an initial administrator account:
  1. Register a Jabber account on your ejabberd server. An account can be created in two ways:
    1. Using the tool ejabberdctl (see section 4.1.2): 
      % ejabberdctl node@host register admin example.org password
    2. Using In-Band Registration (see section 3.3.15): you can use a Jabber client to register an account.
  2. Edit the configuration file to promote the account created in the previous step to an account with administrator rights. Note that if you want to add more administrators, a separate ACL entry is needed for each administrator. 
      {acl, admins, {user, "admin", "example.org"}}.
  {access, configure, [{allow, admins}]}.
  3. Restart ejabberd to load the new configuration.
  4. Open the web interface (http://server:port/admin/) in your favourite browser. Make sure to enter the full JID as username (in this example: admin@example.org. The reason that you also need to enter the suffix, is because ejabberd's virtual hosting support.

Chapter 3  Configuring ejabberd

3.1  Basic Configuration

The configuration file will be loaded the first time you start ejabberd. The content from this file will be parsed and stored in the internal ejabberd database. Subsequently the configuration will be loaded from the database and any commands in the configuration file are appended to the entries in the database.

Note that ejabberd never edits the configuration file. So, the configuration changes done using the web interface are stored in the database, but are not reflected in the configuration file. If you want those changes to be use after ejabberd restart, you can either edit the configuration file, or remove all its content.

The configuration file contains a sequence of Erlang terms. Lines beginning with a `%' sign are ignored. Each term is a tuple of which the first element is the name of an option, and any further elements are that option's values. If the configuration file do not contain for instance the `hosts' option, the old host name(s) stored in the database will be used.

You can override the old values stored in the database by adding next lines to the configuration file: 
  override_global.
  override_local.
  override_acls.
With these lines the old global options (shared between all ejabberd nodes in a cluster), local options (which are specific for this particular ejabberd node) and ACLs will be removed before new ones are added.

3.1.1  Host Names

The option hosts defines a list containing one or more domains that ejabberd will serve.

Examples:

3.1.2  Virtual Hosting

Options can be defined separately for every virtual host using the host_config option. It has the following syntax: 
  {host_config, <hostname>, [<option>, <option>, ...]}.
Examples: If you have several virtual hosts, and you want to define options such as modules with values specific for some virtual host, instead of defining each option with the syntax 
  {<option-name>, <option-value>}
you must use this syntax: 
  {{add, <option-name>}, <option-value>}
Example:

3.1.3  Listened Sockets

The option listen defines for which addresses and ports ejabberd will listen and what services will be run on them. Each element of the list is a tuple with the following elements: The available modules, their purpose and the options allowed by each one are:
ejabberd_c2s Description Handles c2s connections.
  Options access, certfile, inet6, ip, max_stanza_size, shaper, ssl, starttls, starttls_required, tls, zlib
ejabberd_s2s_in Description Handles incoming s2s connections.
  Options inet6, ip, max_stanza_size
ejabberd_service Description Interacts with external components (as defined in the Jabber Component Protocol (XEP-0114).
  Options access, hosts, inet6, ip, shaper
ejabberd_http Description Handles incoming HTTP connections.
  Options certfile, http_poll, inet6, ip, request_handlers, tls, web_admin
This is a detailed description of each option allowed by the listening modules:
{access, <access rule>}
This option defines access to the port. The default value is all.
{certfile, Path}
Full path to a file containing the default SSL certificate. To define a certificate file specific for a given domain, use the global option domain_certfile.
component_check_from
This option can be used with ejabberd_service only. It is used to disable control on the from field on packets send by an external components. The option can be either true or false. The default value is true which conforms to XEP-0114.
{hosts, [Hostnames], [HostOptions]}
This option defines one or more hostnames of connected services and enables you to specify additional options including {password, Secret}.
http_poll
This option enables HTTP Polling (XEP-0025) support. HTTP Polling enables access via HTTP requests to ejabberd from behind firewalls which do not allow outgoing sockets on port 5222.

If HTTP Polling is enabled, it will be available at http://server:port/http-poll/. Be aware that support for HTTP Polling is also needed in the Jabber client. Remark also that HTTP Polling can be interesting to host a web-based Jabber client such as JWChat (there is a tutorial to install JWChat with instructions for ejabberd).
inet6
Set up the socket for IPv6.
{ip, IPAddress}
This option specifies which network interface to listen for. For example {ip, {192, 168, 1, 1}}.
{max_stanza_size, Size}
This option specifies an approximate maximum size in bytes of XML stanzas. Approximate, because it is calculated with the precision of one block of readed data. For example {max_stanza_size, 65536}. The default value is infinity. Recommended values are 65536 for c2s connections and 131072 for s2s connections. s2s max stanza size must always much higher than c2s limit. Change this value with extreme care as it can cause unwanted disconnect if set too low.
{request_handlers, [{Path, Module}]}
To define one or several handlers that will serve HTTP requests. The Path is a list of strings; so the URIs that start with that Path will be served by Module. For example, if you want mod_foo to serve the URIs that start with /a/b/, and you also want mod_http_bind to serve the URIs /http-bind/, use this option: {request_handlers, [{["a", "b"], mod_foo}, {["http-bind"], mod_http_bind}]}
{shaper, <access rule>}
This option defines a shaper for the port (see section 3.1.6). The default value is none.
ssl
This option specifies that traffic on the port will be encrypted using SSL. You should also set the certfile option. It is recommended to use the tls option instead of this one.
starttls
This option specifies that STARTTLS encryption is available on connections to the port. You should also set the certfile option. You can define a certificate file for a specific domain using the global option domain_certfile.
starttls_required
This option specifies that STARTTLS encryption is required on connections to the port. No unencrypted connections will be allowed. You should also set the certfile option. You can define a certificate file for a specific domain using the global option domain_certfile.
tls
This option specifies that traffic on the port will be encrypted using SSL immediately after connecting. You should also set the certfile option.
web_admin
This option enables the web interface for ejabberd administration which is available at http://server:port/admin/. Login and password are the username and password of one of the registered users who are granted access by the `configure' access rule.
zlib
This option specifies that Zlib stream compression (as defined in XEP-0138) is available on connections to the port. Client connections cannot use stream compression and stream encryption simultaneously. Hence, if you specify both tls (or ssl) and zlib, the latter option will not affect connections (there will be no stream compression).
There are some additional global options:
{s2s_use_starttls, true|false}
This option defines whether to use STARTTLS for s2s connections.
{s2s_certfile, Path}
Full path to a file containing a SSL certificate.
{domain_certfile, Domain, Path}
Full path to the file containing the SSL certificate for a specific domain.
For example, the following simple configuration defines: 
{hosts, ["example.com", "example.org", "example.net"]}.
{listen,
 [
  {5222, ejabberd_c2s, [
                        {access, c2s}, 
                        {shaper, c2s_shaper},
                        starttls, {certfile, "/etc/ejabberd/server.pem"},
                        {max_stanza_size, 65536}
                       ]},
  {5223, ejabberd_c2s, [
                        {access, c2s},
                        {shaper, c2s_shaper},
                        tls, {certfile, "/etc/ejabberd/server.pem"},
                        {max_stanza_size, 65536}
                       ]},
  {5269, ejabberd_s2s_in, [
                           {shaper, s2s_shaper},
                           {max_stanza_size, 131072}
                          ]},
  {5280, ejabberd_http, [
                         http_poll
                        ]},
  {5281, ejabberd_http, [
                         web_admin,
                         tls, {certfile, "/etc/ejabberd/server.pem"},
                        ]}
 ]
}.
{s2s_use_starttls, true}.
{s2s_certfile, "/etc/ejabberd/server.pem"}.
{domain_certfile, "example.com", "/etc/ejabberd/example_com.pem"}.
In this example, the following configuration defines that: 
  {acl, blocked, {user, "bad"}}.
  {access, c2s, [{deny, blocked},
                 {allow, all}]}.
  {shaper, normal, {maxrate, 1000}}.
  {access, c2s_shaper, [{none, admin},
                        {normal, all}]}.
  {listen,
   [{5222, ejabberd_c2s,     [{access, c2s}, {shaper, c2s_shaper}]},
    {5223, ejabberd_c2s,     [{access, c2s},
                              ssl, {certfile, "/path/to/ssl.pem"}]},
    {5269, ejabberd_s2s_in,  []},
    {5280, ejabberd_http,    [http_poll, web_admin]},
    {5233, ejabberd_service, [{host, "aim.example.org",
                               [{password, "aimsecret"}]}]},
    {5234, ejabberd_service, [{hosts, ["icq.example.org", "sms.example.org"],
                               [{password, "jitsecret"}]}]},
    {5235, ejabberd_service, [{host, "msn.example.org",
                               [{password, "msnsecret"}]}]},
    {5236, ejabberd_service, [{host, "yahoo.example.org",
                               [{password, "yahoosecret"}]}]},
    {5237, ejabberd_service, [{host, "gg.example.org",
                               [{password, "ggsecret"}]}]},
    {5238, ejabberd_service, [{host, "jmc.example.org",
                               [{password, "jmcsecret"}]}]},
    {5239, ejabberd_service, [{host, "custom.example.org",
                               [{password, "customsecret"}]},
                              {service_check_from, false}]}
   ]
  }.
  {s2s_use_starttls, true}.
  {s2s_certfile, "/path/to/ssl.pem"}.
Note, that for jabberd 1.4- or WPJabber-based services you have to make the transports log and do XDB by themselves: 
  <!--
     You have to add elogger and rlogger entries here when using ejabberd.
     In this case the transport will do the logging.
  -->

  <log id='logger'>
    <host/>
    <logtype/>
    <format>%d: [%t] (%h): %s</format>
    <file>/var/log/jabber/service.log</file>
  </log>

  <!--
     Some Jabber server implementations do not provide
     XDB services (for example, jabberd2 and ejabberd).
     xdb_file.so is loaded in to handle all XDB requests.
  -->

  <xdb id="xdb">
    <host/>
    <load>
      <!-- this is a lib of wpjabber or jabberd -->
      <xdb_file>/usr/lib/jabber/xdb_file.so</xdb_file>
      </load>
    <xdb_file xmlns="jabber:config:xdb_file">
      <spool><jabberd:cmdline flag='s'>/var/spool/jabber</jabberd:cmdline></spool>
    </xdb_file>
  </xdb>

3.1.4  Authentication

The option auth_method defines the authentication method that is used for user authentication: 
  {auth_method, [<method>]}.
The following authentication methods are supported by ejabberd:

Internal

ejabberd uses its internal Mnesia database as the default authentication method. Examples:

SASL Anonymous and Anonymous Login

The anonymous authentication method can be configured with the following options. Remember that you can use the host_config option to set virtual host specific options (see section 3.1.2). Note that there also is a detailed tutorial regarding SASL Anonymous and anonymous login configuration. Those options are defined for each virtual host with the host_config parameter (see section 3.1.2).

Examples:

PAM Authentication

ejabberd supports authentication via Pluggable Authentication Modules (PAM). PAM is currently supported in AIX, FreeBSD, HP-UX, Linux, Mac OS X, NetBSD and Solaris. PAM authentication is disabled by default, so you have to configure and compile ejabberd with PAM support enabled: 
./configure --enable-pam && make install
Options:
pam_service
This option defines the PAM service name. Default is "ejabberd". Refer to the PAM documentation of your operation system for more information.
Example: 
  {auth_method, [pam]}.
  {pam_service, "ejabberd"}.
Though it is quite easy to set up PAM support in ejabberd, PAM itself introduces some security issues:

3.1.5  Access Rules

ACL Definition

Access control in ejabberd is performed via Access Control Lists (ACLs). The declarations of ACLs in the configuration file have the following syntax: 
  {acl, <aclname>, {<acltype>, ...}}.
<acltype> can be one of the following:
all
Matches all JIDs. Example: 
{acl, all, all}.
{user, <username>}
Matches the user with the name <username> at the first virtual host. Example: 
{acl, admin, {user, "yozhik"}}.
{user, <username>, <server>}
Matches the user with the JID <username>@<server> and any resource. Example: 
{acl, admin, {user, "yozhik", "example.org"}}.
{server, <server>}
Matches any JID from server <server>. Example: 
{acl, exampleorg, {server, "example.org"}}.
{user_regexp, <regexp>}
Matches any local user with a name that matches <regexp> on local virtual hosts. Example: 
{acl, tests, {user_regexp, "^test[0-9]*$"}}.
{user_regexp, <regexp>, <server>}
Matches any user with a name that matches <regexp> at server <server>. Example: 
{acl, tests, {user_regexp, "^test", "example.org"}}.
{server_regexp, <regexp>}
Matches any JID from the server that matches <regexp>. Example: 
{acl, icq, {server_regexp, "^icq\\."}}.
{node_regexp, <user_regexp>, <server_regexp>}
Matches any user with a name that matches <user_regexp> at any server that matches <server_regexp>. Example: 
{acl, yohzik, {node_regexp, "^yohzik$", "^example.(com|org)$"}}.
{user_glob, <glob>}
{user_glob, <glob>, <server>}
{server_glob, <glob>}
{node_glob, <user_glob>, <server_glob>}
This is the same as above. However, it uses shell glob patterns instead of regexp. These patterns can have the following special characters:
*
matches any string including the null string.
?
matches any single character.
[...]
matches any of the enclosed characters. Character ranges are specified by a pair of characters separated by a `-'. If the first character after `[' is a `!', any character not enclosed is matched.
The following ACLs are pre-defined:
all
Matches any JID.
none
Matches no JID.

Access Rights

An entry allowing or denying access to different services looks similar to this: 
  {access, <accessname>, [{allow, <aclname>},
                          {deny, <aclname>},
                          ...
                         ]}.
When a JID is checked to have access to <accessname>, the server sequentially checks if that JID matches any of the ACLs that are named in the second elements of the tuples in the list. If it matches, the first element of the first matched tuple is returned, otherwise the value `deny' is returned.

Example: 
  {access, configure, [{allow, admin}]}.
  {access, something, [{deny, badmans},
                       {allow, all}]}.
The following access rules are pre-defined:
all
Always returns the value `allow'.
none
Always returns the value `deny'.

Limiting Opened Sessions with ACL

The special access max_user_sessions specifies the maximum number of sessions (authenticated connections) per user. If a user tries to open more sessions by using different resources, the first opened session will be disconnected. The error session replaced will be sent to the disconnected session. The value for this option can be either a number, or infinity. The default value is infinity.

The syntax is: 
  {access, max_user_sessions, [{<maxnumber>, <aclname>},
                               ...
                              ]}.
Examples:

3.1.6  Shapers

Shapers enable you to limit connection traffic. The syntax of shapers is like this: 
  {shaper, <shapername>, <kind>}.
Currently only one kind of shaper called maxrate is available. It has the following syntax: 
  {maxrate, <rate>}
where <rate> stands for the maximum allowed incoming rate in bytes per second.

Examples:

3.1.7  Default Language

The option language defines the default language of server strings that can be seen by Jabber clients. If a Jabber client do not support xml:lang, the specified language is used. The default value is en. In order to take effect there must be a translation file <language>.msg in ejabberd's msgs directory.

Examples:

3.2  Database and LDAP Configuration

ejabberd uses its internal Mnesia database by default. However, it is possible to use a relational database or an LDAP server to store persistent, long-living data. ejabberd is very flexible: you can configure different authentication methods for different virtual hosts, you can configure different authentication mechanisms for the same virtual host (fallback), you can set different storage systems for modules, and so forth.

The following databases are supported by ejabberd: The following LDAP servers are tested with ejabberd:

3.2.1  MySQL

Although this section will describe ejabberd's configuration when you want to use the native MySQL driver, it does not describe MySQL's installation and database creation. Check the MySQL documentation and the tutorial Using ejabberd with MySQL native driver for information regarding these topics. Note that the tutorial contains information about ejabberd's configuration which is duplicate to this section.

Moreover, the file mysql.sql in the directory src/odbc might be interesting for you. This file contains the ejabberd schema for MySQL. At the end of the file you can find information to update your database schema.

Driver Compilation

You can skip this step if you installed ejabberd using a binary installer or if the binary packages of ejabberd you are using include support for MySQL.
  1. First, install the Erlang MySQL library. Make sure the compiled files are in your Erlang path; you can put them for example in the same directory as your ejabberd .beam files.
  2. Then, configure and install ejabberd with ODBC support enabled (this is also needed for native MySQL support!). This can be done, by using next commands: 
    ./configure --enable-odbc && make install

Authentication

The option value name may be misleading, as the auth_method name is used for access to a relational database through ODBC, as well as through the native MySQL interface. Anyway, the first configuration step is to define the odbc auth_method. For example: 
{host_config, "public.example.org", [{auth_method, [odbc]}]}.
The actual database access is defined in the option odbc_server. Its value is used to define if we want to use ODBC, or one of the two native interface available, PostgreSQL or MySQL.

To use the native MySQL interface, you can pass a tuple of the following form as parameter: 
{mysql, "Server", "Database", "Username", "Password"}
mysql is a keyword that should be kept as is. For example: 
{odbc_server, {mysql, "localhost", "test", "root", "password"}}.
Optionally, it is possible to define the MySQL port to use. This option is only useful, in very rare cases, when you are not running MySQL with the default port setting. The mysql parameter can thus take the following form: 
{mysql, "Server", Port, "Database", "Username", "Password"}
The Port value should be an integer, without quotes. For example: 
{odbc_server, {mysql, "localhost", Port, "test", "root", "password"}}.

Storage

MySQL also can be used to store information into from several ejabberd modules. See section 3.3.1 to see which modules have a version with the `_odbc'. This suffix indicates that the module can be used with relational databases like MySQL. To enable storage to your database, just make sure that your database is running well (see previous sections), and replace the suffix-less or ldap module variant with the odbc module variant. Keep in mind that you cannot have several variants of the same module loaded!

3.2.2  Microsoft SQL Server

Although this section will describe ejabberd's configuration when you want to use Microsoft SQL Server, it does not describe Microsoft SQL Server's installation and database creation. Check the MySQL documentation and the tutorial Using ejabberd with MySQL native driver for information regarding these topics. Note that the tutorial contains information about ejabberd's configuration which is duplicate to this section.

Moreover, the file mssql.sql in the directory src/odbc might be interesting for you. This file contains the ejabberd schema for Microsoft SQL Server. At the end of the file you can find information to update your database schema.

Driver Compilation

You can skip this step if you installed ejabberd using a binary installer or if the binary packages of ejabberd you are using include support for ODBC.

If you want to use Microsoft SQL Server with ODBC, you need to configure, compile and install ejabberd with support for ODBC and Microsoft SQL Server enabled. This can be done, by using next commands: 
./configure --enable-odbc --enable-mssql && make install

Authentication

The configuration of Microsoft SQL Server is the same as the configuration of ODBC compatible servers (see section 3.2.4).

Storage

Microsoft SQL Server also can be used to store information into from several ejabberd modules. See section 3.3.1 to see which modules have a version with the `_odbc'. This suffix indicates that the module can be used with relational databases like Microsoft SQL Server. To enable storage to your database, just make sure that your database is running well (see previous sections), and replace the suffix-less or ldap module variant with the odbc module variant. Keep in mind that you cannot have several variants of the same module loaded!

3.2.3  PostgreSQL

Although this section will describe ejabberd's configuration when you want to use the native PostgreSQL driver, it does not describe PostgreSQL's installation and database creation. Check the PostgreSQL documentation and the tutorial Using ejabberd with MySQL native driver for information regarding these topics. Note that the tutorial contains information about ejabberd's configuration which is duplicate to this section.

Also the file pg.sql in the directory src/odbc might be interesting for you. This file contains the ejabberd schema for PostgreSQL. At the end of the file you can find information to update your database schema.

Driver Compilation

You can skip this step if you installed ejabberd using a binary installer or if the binary packages of ejabberd you are using include support for PostgreSQL.
  1. First, install the Erlang PgSQL library from Jungerl. Make sure the compiled files are in your Erlang path; you can put them for example in the same directory as your ejabberd .beam files.
  2. Then, configure, compile and install ejabberd with ODBC support enabled (this is also needed for native PostgreSQL support!). This can be done, by using next commands: 
    ./configure --enable-odbc && make install

Authentication

The option value name may be misleading, as the auth_method name is used for access to a relational database through ODBC, as well as through the native PostgreSQL interface. Anyway, the first configuration step is to define the odbc auth_method. For example: 
{host_config, "public.example.org", [{auth_method, [odbc]}]}.
The actual database access is defined in the option odbc_server. Its value is used to define if we want to use ODBC, or one of the two native interface available, PostgreSQL or MySQL.

To use the native PostgreSQL interface, you can pass a tuple of the following form as parameter: 
{pgsql, "Server", "Database", "Username", "Password"}
pgsql is a keyword that should be kept as is. For example: 
{odbc_server, {pgsql, "localhost", "database", "ejabberd", "password"}}.
Optionally, it is possible to define the PostgreSQL port to use. This option is only useful, in very rare cases, when you are not running PostgreSQL with the default port setting. The pgsql parameter can thus take the following form: 
{pgsql, "Server", Port, "Database", "Username", "Password"}
The Port value should be an integer, without quotes. For example: 
{odbc_server, {pgsql, "localhost", 5432, "database", "ejabberd", "password"}}.

Storage

PostgreSQL also can be used to store information into from several ejabberd modules. See section 3.3.1 to see which modules have a version with the `_odbc'. This suffix indicates that the module can be used with relational databases like PostgreSQL. To enable storage to your database, just make sure that your database is running well (see previous sections), and replace the suffix-less or ldap module variant with the odbc module variant. Keep in mind that you cannot have several variants of the same module loaded!

3.2.4  ODBC Compatible

Although this section will describe ejabberd's configuration when you want to use the ODBC driver, it does not describe the installation and database creation of your database. Check the documentation of your database. The tutorial Using ejabberd with MySQL native driver also can help you. Note that the tutorial contains information about ejabberd's configuration which is duplicate to this section.

Compilation

You can skip this step if you installed ejabberd using a binary installer or if the binary packages of ejabberd you are using include support for ODBC.
  1. First, install the Erlang MySQL library. Make sure the compiled files are in your Erlang path; you can put them for example in the same directory as your ejabberd .beam files.
  2. Then, configure, compile and install ejabberd with ODBC support enabled. This can be done, by using next commands: 
    ./configure --enable-odbc && make install

Authentication

The first configuration step is to define the odbc auth_method. For example: 
{host_config, "public.example.org", [{auth_method, [odbc]}]}.
The actual database access is defined in the option odbc_server. Its value is used to defined if we want to use ODBC, or one of the two native interface available, PostgreSQL or MySQL.

To use a relational database through ODBC, you can pass the ODBC connection string as odbc_server parameter. For example: 
{odbc_server, "DSN=database;UID=ejabberd;PWD=password"}.

Storage

An ODBC compatible database also can be used to store information into from several ejabberd modules. See section 3.3.1 to see which modules have a version with the `_odbc'. This suffix indicates that the module can be used with ODBC compatible relational databases. To enable storage to your database, just make sure that your database is running well (see previous sections), and replace the suffix-less or ldap module variant with the odbc module variant. Keep in mind that you cannot have several variants of the same module loaded!

3.2.5  LDAP

ejabberd has built-in LDAP support. You can authenticate users against LDAP server and use LDAP directory as vCard storage. Shared rosters are not supported yet.

Connection

Parameters:
ldap_server
IP address or dns name of your LDAP server. This option is required.
ldap_port
Port to connect to your LDAP server. The initial default value is 389, so it is used when nothing is set into the configuration file. If you configure a value, it is stored in ejabberd's database. Then, if you remove that value from the configuration file, the value previously stored in the database will be used instead of the default 389.
ldap_rootdn
Bind DN. The default value is "" which means `anonymous connection'.
ldap_password
Bind password. The default value is "".
Example: 
  {auth_method, ldap}.
  {ldap_servers, ["ldap.example.org"]}.
  {ldap_port, 389}.
  {ldap_rootdn, "cn=Manager,dc=domain,dc=org"}.
  {ldap_password, "secret"}.
Note that current LDAP implementation does not support SSL secured communication and SASL authentication.

Authentication

You can authenticate users against an LDAP directory. Available options are:
ldap_base
LDAP base directory which stores users accounts. This option is required.
ldap_uids
LDAP attribute which holds a list of attributes to use as alternatives for getting the JID. The value is of the form: [{ldap_uidattr}] or [{ldap_uidattr, ldap_uidattr_format}]. You can use as many comma separated tuples {ldap_uidattr, ldap_uidattr_format} that is needed. The default value is [{"uid", "%u"}]. The defaut ldap_uidattr_format is "%u". The values for ldap_uidattr and ldap_uidattr_format are described as follow:
ldap_uidattr
LDAP attribute which holds the user's part of a JID. The default value is "uid".
ldap_uidattr_format
Format of the ldap_uidattr variable. The format must contain one and only one pattern variable "%u" which will be replaced by the user's part of a JID. For example, "%u@example.org". The default value is "%u".
ldap_filter
RFC 2254 LDAP filter. The default is none. Example: "(&(objectClass=shadowAccount)(memberOf=Jabber Users))". Please, do not forget to close brackets and do not use superfluous whitespaces. Also you must not use ldap_uidattr attribute in filter because this attribute will be substituted in LDAP filter automatically.

Examples

Common example
Let's say ldap.example.org is the name of our LDAP server. We have users with their passwords in "ou=Users,dc=example,dc=org" directory. Also we have addressbook, which contains users emails and their additional infos in "ou=AddressBook,dc=example,dc=org" directory. Corresponding authentication section should looks like this: 
  %% authentication method
  {auth_method, ldap}.
  %% DNS name of our LDAP server
  {ldap_servers, ["ldap.example.org"]}.
  %% Bind to LDAP server as "cn=Manager,dc=example,dc=org" with password "secret"
  {ldap_rootdn, "cn=Manager,dc=example,dc=org"}.
  {ldap_password, "secret"}.
  %% define the user's base
  {ldap_base, "ou=Users,dc=example,dc=org"}.
  %% We want to authorize users from 'shadowAccount' object class only
  {ldap_filter, "(objectClass=shadowAccount)"}.
Now we want to use users LDAP-info as their vCards. We have four attributes defined in our LDAP schema: "mail" — email address, "givenName" — first name, "sn" — second name, "birthDay" — birthday. Also we want users to search each other. Let's see how we can set it up: 
  {modules,
    ...
    {mod_vcard_ldap,
     [
      %% We use the same server and port, but want to bind anonymously because
      %% our LDAP server accepts anonymous requests to
      %% "ou=AddressBook,dc=example,dc=org" subtree.
      {ldap_rootdn, ""},
      {ldap_password, ""},
      %% define the addressbook's base
      {ldap_base, "ou=AddressBook,dc=example,dc=org"},
      %% uidattr: user's part of JID is located in the "mail" attribute
      %% uidattr_format: common format for our emails
      {ldap_uids, [{"mail", "%u@mail.example.org"}]},
      %% We have to define empty filter here, because entries in addressbook does not
      %% belong to shadowAccount object class
      {ldap_filter, ""},
      %% Now we want to define vCard pattern
      {ldap_vcard_map,
       [{"NICKNAME", "%u", []}, % just use user's part of JID as his nickname
        {"GIVEN", "%s", ["givenName"]},
        {"FAMILY", "%s", ["sn"]},
        {"FN", "%s, %s", ["sn", "givenName"]}, % example: "Smith, John"
        {"EMAIL", "%s", ["mail"]},
        {"BDAY", "%s", ["birthDay"]}]},
      %% Search form
      {ldap_search_fields,
       [{"User", "%u"},
        {"Name", "givenName"},
        {"Family Name", "sn"},
        {"Email", "mail"},
        {"Birthday", "birthDay"}]},
      %% vCard fields to be reported
      %% Note that JID is always returned with search results
      {ldap_search_reported,
       [{"Full Name", "FN"},
        {"Nickname", "NICKNAME"},
        {"Birthday", "BDAY"}]}
    ]},
    ...
  }.
Note that mod_vcard_ldap module checks for the existence of the user before searching in his information in LDAP.

Active Directory
Active Directory is just an LDAP-server with predefined attributes. A sample configuration is shown below: 
  {auth_method, ldap}.
  {ldap_servers, ["office.org"]}.    % List of LDAP servers
  {ldap_base, "DC=office,DC=org"}. % Search base of LDAP directory
  {ldap_rootdn, "CN=Administrator,CN=Users,DC=office,DC=org"}. % LDAP manager
  {ldap_password, "*******"}. % Password to LDAP manager
  {ldap_uids, [{"sAMAccountName"}]}.
  {ldap_filter, "(memberOf=*)"}.

  {modules,
    ...
    {mod_vcard_ldap,
     [{ldap_vcard_map,
       [{"NICKNAME", "%u", []},
        {"GIVEN", "%s", ["givenName"]},
        {"MIDDLE", "%s", ["initials"]},
        {"FAMILY", "%s", ["sn"]},
        {"FN", "%s", ["displayName"]},
        {"EMAIL", "%s", ["mail"]},
        {"ORGNAME", "%s", ["company"]},
        {"ORGUNIT", "%s", ["department"]},
        {"CTRY", "%s", ["c"]},
        {"LOCALITY", "%s", ["l"]},
        {"STREET", "%s", ["streetAddress"]},
        {"REGION", "%s", ["st"]},
        {"PCODE", "%s", ["postalCode"]},
        {"TITLE", "%s", ["title"]},
        {"URL", "%s", ["wWWHomePage"]},
        {"DESC", "%s", ["description"]},
        {"TEL", "%s", ["telephoneNumber"]}]},
      {ldap_search_fields,
       [{"User", "%u"},
        {"Name", "givenName"},
        {"Family Name", "sn"},
        {"Email", "mail"},
        {"Company", "company"},
        {"Department", "department"},
        {"Role", "title"},
        {"Description", "description"},
        {"Phone", "telephoneNumber"}]},
      {ldap_search_reported,
       [{"Full Name", "FN"},
        {"Nickname", "NICKNAME"},
        {"Email", "EMAIL"}]}
    ]},
    ...
  }.

3.3  Modules Configuration

The option modules defines the list of modules that will be loaded after ejabberd's startup. Each entry in the list is a tuple in which the first element is the name of a module and the second is a list of options for that module.

Examples:

3.3.1  Overview

The following table lists all modules available in the official ejabberd distribution. You can find more contributed modules on the ejabberd website. Please remember that these contributions might not work or that they can contain severe bugs and security leaks. Therefore, use them at your own risk!

You can see which database backend each module needs by looking at the suffix: If you want to It is possible to use a relational database to store pieces of information. You can do this by changing the module name to a name with an _odbc suffix in ejabberd config file. You can use a relational database for the following data:
Module Feature Dependencies Needed for XMPP?
mod_adhoc Ad-Hoc Commands (XEP-0050)   No
mod_announce Manage announcements mod_adhoc No
mod_configure Support for online mod_adhoc No
  configuration of ejabberd    
mod_disco Service Discovery (XEP-0030)   No
mod_echo Echoes Jabber packets   No
mod_irc IRC transport   No
mod_last Last Activity (XEP-0012)   No
mod_last_odbc Last Activity (XEP-0012) supported database (*) No
mod_muc Multi-User Chat (XEP-0045)   No
mod_muc_log Multi-User Chat room logging mod_muc No
mod_offline Offline message storage   No
mod_offline_odbc Offline message storage supported database (*) No
mod_privacy Blocking Communication   Yes
mod_private Private XML Storage (XEP-0049)   No
mod_private_odbc Private XML Storage (XEP-0049) supported database (*) No
mod_proxy65 SOCKS5 Bytestreams (XEP-0065)   No
mod_pubsub Publish-Subscribe (XEP-0060)   No
mod_register In-Band Registration (XEP-0077)   No
mod_roster Roster management   Yes (**)
mod_roster_odbc Roster management supported database (*) Yes (**)
mod_service_log Copy user messages to logger service   No
mod_shared_roster Shared roster management mod_roster or No
    mod_roster_odbc  
mod_stats Statistics Gathering (XEP-0039)   No
mod_time Entity Time (XEP-0090)   No
mod_vcard vcard-temp (XEP-0054)   No
mod_vcard_ldap vcard-temp (XEP-0054) LDAP server No
mod_vcard_odbc vcard-temp (XEP-0054) supported database (*) No
mod_version Software Version (XEP-0092)   No

3.3.2  Common Options

The following options are used by many modules. Therefore, they are described in this separate section.

iqdisc

Many modules define handlers for processing IQ queries of different namespaces to this server or to a user (e. g. to example.org or to user@example.org). This option defines processing discipline for these queries. Possible values are:
no_queue
All queries of a namespace with this processing discipline are processed immediately. This also means that no other packets can be processed until this one has been completely processed. Hence this discipline is not recommended if the processing of a query can take a relatively long time.
one_queue
In this case a separate queue is created for the processing of IQ queries of a namespace with this discipline. In addition, the processing of this queue is done in parallel with that of other packets. This discipline is most recommended.
parallel
For every packet with this discipline a separate Erlang process is spawned. Consequently, all these packets are processed in parallel. Although spawning of Erlang process has a relatively low cost, this can break the server's normal work, because the Erlang emulator has a limit on the number of processes (32000 by default).
Example: 
  {modules,
   [
    ...
    {mod_time, [{iqdisc, no_queue}]},
    ...
   ]}.

host

This option defines the Jabber ID of a service provided by an ejabberd module. The keyword "@HOST@" is replaced at start time with the real virtual host string.

This example configures the echo module to provide its echoing service in the Jabber ID mirror.example.org: 
  {modules,
   [
    ...
    {mod_echo, [{host, "mirror.example.org"}]},
    ...
   ]}.
However, if there are several virtual hosts and this module is enabled in all of them, the "@HOST@" keyword must be used: 
  {modules,
   [
    ...
    {mod_echo, [{host, "mirror.@HOST@"}]},
    ...
   ]}.

3.3.3  mod_announce

This module enables configured users to broadcast announcements and to set the message of the day (MOTD). Configured users can do these actions with their Jabber client using Ad-hoc commands or by sending messages to specific JIDs. These JIDs are listed in next paragraph. The first JID in each entry will apply only to the virtual host example.org, while the JID between brackets will apply to all virtual hosts:
example.org/announce/all (example.org/announce/all-hosts/all)
The message is sent to all registered users. If the user is online and connected to several resources, only the resource with the highest priority will receive the message. If the registered user is not connected, the message will be stored offline in assumption that offline storage (see section 3.3.10) is enabled.
example.org/announce/online (example.org/announce/all-hosts/online)
The message is sent to all connected users. If the user is online and connected to several resources, all resources will receive the message.
example.org/announce/motd (example.org/announce/all-hosts/motd)
The message is set as the message of the day (MOTD) and is sent to users when they login. In addition the message is sent to all connected users (similar to announce/online).
example.org/announce/motd/update (example.org/announce/all-hosts/motd/update)
The message is set as message of the day (MOTD) and is sent to users when they login. The message is not sent to any currently connected user.
example.org/announce/motd/delete (example.org/announce/all-hosts/motd/delete)
Any message sent to this JID removes the existing message of the day (MOTD).
Options:
access
This option specifies who is allowed to send announcements and to set the message of the day (by default, nobody is able to send such messages).
Examples: Note that mod_announce can be resource intensive on large deployments as it can broadcast lot of messages. This module should be disabled for instances of ejabberd with hundreds of thousands users.

3.3.4  mod_disco

This module adds support for Service Discovery (XEP-0030). With this module enabled, services on your server can be discovered by Jabber clients. Note that ejabberd has no modules with support for the superseded Jabber Browsing (XEP-0011) and Agent Information (XEP-0094). Accordingly, Jabber clients need to have support for the newer Service Discovery protocol if you want them be able to discover the services you offer.

Options:
iqdisc
This specifies the processing discipline for Service Discovery (http://jabber.org/protocol/disco#items and http://jabber.org/protocol/disco#info) IQ queries (see section 3.3.2).
extra_domains
With this option, extra domains can be added to the Service Discovery item list.
Examples:

3.3.5  mod_echo

This module simply echoes any Jabber packet back to the sender. This mirror can be of interest for ejabberd and Jabber client debugging.

Options:
host
This option defines the Jabber ID of the service. If the host option is not specified, the Jabber ID will be the hostname of the virtual host with the prefix `echo.'. The keyword "@HOST@" is replaced at start time with the real virtual host name.
Example: Mirror, mirror, on the wall, who is the most beautiful of them all? 
  {modules,
   [
    ...
    {mod_echo, [{host, "mirror.example.org"}]},
    ...
   ]}.

3.3.6  mod_irc

This module is an IRC transport that can be used to join channels on IRC servers.

End user information: Options:
host
This option defines the Jabber ID of the service. If the host option is not specified, the Jabber ID will be the hostname of the virtual host with the prefix `irc.'. The keyword "@HOST@" is replaced at start time with the real virtual host name.
access
This option can be used to specify who may use the IRC transport (default value: all).
default_encoding
Set the default IRC encoding (default value: "koi8-r").
Examples:

3.3.7  mod_last

This module adds support for Last Activity (XEP-0012). It can be used to discover when a disconnected user last accessed the server, to know when a connected user was last active on the server, or to query the uptime of the ejabberd server.

Options:
iqdisc
This specifies the processing discipline for Last activity (jabber:iq:last) IQ queries (see section 3.3.2).

3.3.8  mod_muc

With this module enabled, your server will support Multi-User Chat (XEP-0045). End users will be able to join text conferences.

Some of the features of Multi-User Chat: The MUC service allows any Jabber ID to register a nickname, so nobody else can use that nickname in any room in the MUC service. To register a nickname, open the Service Discovery in your Jabber client and Register in the MUC service.

The MUC service allows the service administrator to send a message to all existing chatrooms. To do so, send the message to the Jabber ID of the MUC service.

This module supports clustering and load balancing. One module can be started per cluster node. Rooms are distributed at creation time on all available MUC module instances. The multi-user chat module is clustered but the room themselves are not clustered nor fault-tolerant: if the node managing a set of rooms goes down, the rooms disappear and they will be recreated on an available node on first connection attempt.

Options:
host
This option defines the Jabber ID of the service. If the host option is not specified, the Jabber ID will be the hostname of the virtual host with the prefix `conference.'. The keyword "@HOST@" is replaced at start time with the real virtual host name.
access
You can specify who is allowed to use the Multi-User Chat service (by default, everyone is allowed to use it).
access_create
To configure who is allowed to create new rooms at the Multi-User Chat service, this option can be used (by default, everybody is allowed to create rooms).
access_persistent
To configure who is allowed to modify the 'persistent' chatroom option (by default, everybody is allowed to modify that option).
access_admin
This option specifies who is allowed to administrate the Multi-User Chat service (the default value is none, which means that only the room creator can administer his room). By sending a message to the service JID, administrators can send service messages that will be displayed in every active room.

history_size
A small history of the current discussion is sent to users when they enter the room. With this option you can define the number of history messages to keep and send to users joining the room. The value is an integer. Setting the value to 0 disables the history feature and, as a result, nothing is kept in memory. The default value is 20. This value is global and thus affects all rooms on the server.

max_users
This option defines at the server level, the maximum number of users allowed per MUC room. It can be lowered in each room configuration but cannot be increased in individual MUC room configuration. The default value is 200.

max_users_admin_threshold
This option defines the number of MUC admins or owners to allow to enter the room even if the maximum number of allowed users is reached. The default limits is 5. In most cases this default value is the best setting.

max_user_conferences
This option define the maximum number of chat room any given user will be able to join. The default is 10. This option is used to prevent possible abuses. Note that this is a soft limits: Some users can sometime join more conferences in cluster configurations.

min_message_interval
This option defines the minimum interval between two messages send by a user in seconds. This option is global and valid for all chat rooms. A decimal value can be used. When this option is not defined, message rate is not limited. This feature can be used to protect a MUC service from users abuses and limit number of messages that will be broadcasted by the service. A good value for this minimum message interval is 0.4 second. If a user tries to send messages faster, an error is send back explaining that the message have been discarded and describing the reason why the message is not acceptable.

min_presence_interval
This option defines the minimum of time between presence changes coming from a given user in seconds. This option is global and valid for all chat rooms. A decimal value can be used. When this option is not defined, no restriction is applied. This option can be used to protect a MUC service for users abuses, as fastly changing a user presence will result in possible large presence packet broadcast. If a user tries to change its presence more often than the specified interval, the presence is cached by ejabberd and only the last presence is broadcasted to all users in the room after expiration of the interval delay. Intermediate presence packets are silently discarded. A good value for this option is 4 seconds.

default_room_opts
This option allow to define the desired default room options. Obviously, the room creator can modify the room options at any time. The available room options are: allow_change_subj, allow_private_messages, allow_query_users, allow_user_invites, anonymous, logging, members_by_default, members_only, moderated, password, password_protected, persistent, public, public_list, title. All of them can be set to true or false, except password and title which are strings.
Examples:

3.3.9  mod_muc_log

This module enables optional logging of Multi-User Chat (MUC) conversations to HTML. Once you enable this module, users can join a chatroom using a MUC capable Jabber client, and if they have enough privileges, they can request the configuration form in which they can set the option to enable chatroom logging.

Features: Options:
access_log
This option restricts which users are allowed to enable or disable chatroom logging. The default value is muc_admin. Note for this default setting you need to have an access rule for muc_admin in order to take effect.
cssfile
With this option you can set whether the HTML files should have a custom CSS file or if they need to use the embedded CSS file. Allowed values are false and an URL to a CSS file. With the first value, HTML files will include the embedded CSS code. With the latter, you can specify the URL of the custom CSS file (for example: `http://example.com/my.css'). The default value is false.
dirtype
The type of the created directories can be specified with this option. Allowed values are subdirs and plain. With the first value, subdirectories are created for each year and month. With the latter, the names of the log files contain the full date, and there are no subdirectories. The default value is subdirs.
outdir
This option sets the full path to the directory in which the HTML files should be stored. Make sure the ejabberd daemon user has write access on that directory. The default value is "www/muc".
timezone
The time zone for the logs is configurable with this option. Allowed values are local and universal. With the first value, the local time, as reported to Erlang by the operating system, will be used. With the latter, GMT/UTC time will be used. The default value is local.
spam_prevention
To prevent spam, the spam_prevention option adds a special attribute to links that prevent their indexation by search engines. The default value is true, which mean that nofollow attributes will be added to user submitted links.
top_link
With this option you can customize the link on the top right corner of each log file. The syntax of this option is {"URL", "Text"}. The default value is {"/", "Home"}.
Examples:

3.3.10  mod_offline

This module implements offline message storage. This means that all messages sent to an offline user will be stored on the server until that user comes online again. Thus it is very similar to how email works. Note that ejabberdctl has a command to delete expired messages (see section 4.1.2).
user_max_messages
This option is use to set a max number of offline messages per user (quota). Its value can be either infinity or a strictly positive integer. The default value is infinity.

3.3.11  mod_privacy

This module implements Blocking Communication (also known as Privacy Rules) as defined in section 10 from XMPP IM. If end users have support for it in their Jabber client, they will be able to:
(from http://www.xmpp.org/specs/rfc3921.html#privacy)
Options:
iqdisc
This specifies the processing discipline for Blocking Communication (jabber:iq:privacy) IQ queries (see section 3.3.2).

3.3.12  mod_private

This module adds support for Private XML Storage (XEP-0049):
Using this method, Jabber entities can store private data on the server and retrieve it whenever necessary. The data stored might be anything, as long as it is valid XML. One typical usage for this namespace is the server-side storage of client-specific preferences; another is Bookmark Storage (XEP-0048).
Options:
iqdisc
This specifies the processing discipline for Private XML Storage (jabber:iq:private) IQ queries (see section 3.3.2).

3.3.13  mod_proxy65

This module implements SOCKS5 Bytestreams (XEP-0065). It allows ejabberd to act as a file transfer proxy between two XMPP clients.

Options:
host
This option defines the hostname of the service. If this option is not set, the prefix `proxy.' is added to ejabberd hostname.
name
Defines Service Discovery name of the service. Default is "SOCKS5 Bytestreams".
ip
This option specifies which network interface to listen for. Default is an IP address of the service's DNS name, or, if fails, {127,0,0,1}.
port
This option defines port to listen for incoming connections. Default is 7777.
auth_type
SOCKS5 authentication type. Possible values are anonymous and plain. Default is anonymous.
access
Defines ACL for file transfer initiators. Default is all.
max_connections
Maximum number of active connections per file transfer initiator. No limit by default.
shaper
This option defines shaper for the file transfer peers. Shaper with the maximum bandwidth will be selected. Default is none.
Examples:

3.3.14  mod_pubsub

This module offers a Publish-Subscribe Service (XEP-0060). Publish-Subscribe can be used to develop (examples are taken from the XEP):
Another example is J-EAI. This is an XMPP-based Enterprise Application Integration (EAI) platform (also known as ESB, the Enterprise Service Bus). The J-EAI project builts upon ejabberd's codebase and has contributed several features to mod_pubsub.

Options:
host
This option defines the Jabber ID of the service. If the host option is not specified, the Jabber ID will be the hostname of the virtual host with the prefix `pubsub.'. The keyword "@HOST@" is replaced at start time with the real virtual host name.
served_hosts
To specify which hosts needs to be served, you can use this option. If absent, only the main ejabberd host is served.
access_createnode
This option restricts which users are allowed to create pubsub nodes using ACL and ACCESS. The default value is pubsub_createnode.
plugins
To specify which pubsub node plugins to use. If not defined, the default plugin is always used.
nodetree
To specify which nodetree plugin to use. If not defined, the default pubsub nodetree used. Nodetrees are default and virtual. Only one nodetree can be used and is shared by all node plugins.
Example: 
  {modules,
   [
    ...
    {mod_pubsub, [{served_hosts, ["example.com",
                                  "example.org"]},
                  {access_createnode, pubsub_createnode},
                  {plugins, ["default","pep"]}]}
    ...
   ]}.

3.3.15  mod_register

This module adds support for In-Band Registration (XEP-0077). This protocol enables end users to use a Jabber client to: Options:
access
This option can be configured to specify rules to restrict registration. If a rule returns `deny' on the requested user name, registration for that user name is denied. (there are no restrictions by default).
welcome_message
Set a welcome message that is sent to each newly registered account. The first string is the subject, and the second string is the message body.
registration_watchers
This option defines a list of JIDs which will be notified each time a new account is registered.
iqdisc
This specifies the processing discipline for In-Band Registration (jabber:iq:register) IQ queries (see section 3.3.2).
Examples:

3.3.16  mod_roster

This module implements roster management as defined in RFC 3921: XMPP IM.

Options:
iqdisc
This specifies the processing discipline for Roster Management (jabber:iq:roster) IQ queries (see section 3.3.2).

3.3.17  mod_service_log

This module adds support for logging end user packets via a Jabber message auditing service such as Bandersnatch. All user packets are encapsulated in a <route/> element and sent to the specified service(s).

Options:
loggers
With this option a (list of) service(s) that will receive the packets can be specified.
Examples:

3.3.18  mod_shared_roster

This module enables you to create shared roster groups. This means that you can create groups of people that can see members from (other) groups in their rosters. The big advantages of this feature are that end users do not need to manually add all users to their rosters, and that they cannot permanently delete users from the shared roster groups.

Shared roster groups can be edited only via the web interface. Each group has a unique identification and the following parameters:
Name
The name of the group, which will be displayed in the roster.
Description
The description of the group. This parameter does not affect anything.
Members
A list of full JIDs of group members, entered one per line in the web interface.
Displayed groups
A list of groups that will be in the rosters of this group's members.
Examples:

3.3.19  mod_stats

This module adds support for Statistics Gathering (XEP-0039). This protocol allows you to retrieve next statistics from your ejabberd deployment: Options:
iqdisc
This specifies the processing discipline for Statistics Gathering (http://jabber.org/protocol/stats) IQ queries (see section 3.3.2).
As there are only a small amount of clients (for example Tkabber) and software libraries with support for this XEP, a few examples are given of the XML you need to send in order to get the statistics. Here they are:

3.3.20  mod_time

This module features support for Entity Time (XEP-0090). By using this XEP, you are able to discover the time at another entity's location.

Options:
iqdisc
This specifies the processing discipline for Entity Time (jabber:iq:time) IQ queries (see section 3.3.2).

3.3.21  mod_vcard

This module allows end users to store and retrieve their vCard, and to retrieve other users vCards, as defined in vcard-temp (XEP-0054). The module also implements an uncomplicated Jabber User Directory based on the vCards of these users. Moreover, it enables the server to send its vCard when queried.

Options:
host
This option defines the Jabber ID of the service. If the host option is not specified, the Jabber ID will be the hostname of the virtual host with the prefix `vjud.'. The keyword "@HOST@" is replaced at start time with the real virtual host name.
iqdisc
This specifies the processing discipline for vcard-temp IQ queries (see section 3.3.2).
search
This option specifies whether the search functionality is enabled (value: true) or disabled (value: false). If disabled, the option host will be ignored and the Jabber User Directory service will not appear in the Service Discovery item list. The default value is true.
matches
With this option, the number of reported search results can be limited. If the option's value is set to infinity, all search results are reported. The default value is 30.
allow_return_all
This option enables you to specify if search operations with empty input fields should return all users who added some information to their vCard. The default value is false.
search_all_hosts
If this option is set to true, search operations will apply to all virtual hosts. Otherwise only the current host will be searched. The default value is true.
Examples:

3.3.22  mod_vcard_ldap

ejabberd can map LDAP attributes to vCard fields. This behaviour is implemented in the mod_vcard_ldap module. This module does not depend on the authentication method (see 3.2.5). The mod_vcard_ldap module has its own optional parameters. The first group of parameters has the same meaning as the top-level LDAP parameters to set the authentication method: ldap_servers, ldap_port, ldap_rootdn, ldap_password, ldap_base, ldap_uids, and ldap_filter. See section 3.2.5 for detailed information about these options. If one of these options is not set, ejabberd will look for the top-level option with the same name. The second group of parameters consists of the following mod_vcard_ldap-specific options:
host
This option defines the Jabber ID of the service. If the host option is not specified, the Jabber ID will be the hostname of the virtual host with the prefix `vjud.'. The keyword "@HOST@" is replaced at start time with the real virtual host name.
iqdisc
This specifies the processing discipline for vcard-temp IQ queries (see section 3.3.2).
search
This option specifies whether the search functionality is enabled (value: true) or disabled (value: false). If disabled, the option host will be ignored and the Jabber User Directory service will not appear in the Service Discovery item list. The default value is true.
ldap_vcard_map
With this option you can set the table that maps LDAP attributes to vCard fields. The format is: [Name_of_vCard_field, Pattern, List_of_LDAP_attributes, ...]. Name_of_vcard_field is the type name of the vCard as defined in RFC 2426. Pattern is a string which contains pattern variables "%u", "%d" or "%s". List_of_LDAP_attributes is the list containing LDAP attributes. The pattern variables "%s" will be sequentially replaced with the values of LDAP attributes from List_of_LDAP_attributes, "%u" will be replaced with the user part of a JID, and "%d" will be replaced with the domain part of a JID. The default is: 
  [{"NICK", "%u", []},
   {"FN", "%s", ["displayName"]},
   {"LAST", "%s", ["sn"]},
   {"FIRST", "%s", ["givenName"]},
   {"MIDDLE", "%s", ["initials"]},
   {"ORGNAME", "%s", ["o"]},
   {"ORGUNIT", "%s", ["ou"]},
   {"CTRY", "%s", ["c"]},
   {"LOCALITY", "%s", ["l"]},
   {"STREET", "%s", ["street"]},
   {"REGION", "%s", ["st"]},
   {"PCODE", "%s", ["postalCode"]},
   {"TITLE", "%s", ["title"]},
   {"URL", "%s", ["labeleduri"]},
   {"DESC", "%s", ["description"]},
   {"TEL", "%s", ["telephoneNumber"]},
   {"EMAIL", "%s", ["mail"]},
   {"BDAY", "%s", ["birthDay"]},
   {"ROLE", "%s", ["employeeType"]},
   {"PHOTO", "%s", ["jpegPhoto"]}]
ldap_search_fields
This option defines the search form and the LDAP attributes to search within. The format is: [Name, Attribute, ...]. Name is the name of a search form field which will be automatically translated by using the translation files (see msgs/*.msg for available words). Attribute is the LDAP attribute or the pattern "%u". The default is: 
  [{"User", "%u"},
   {"Full Name", "displayName"},
   {"Given Name", "givenName"},
   {"Middle Name", "initials"},
   {"Family Name", "sn"},
   {"Nickname", "%u"},
   {"Birthday", "birthDay"},
   {"Country", "c"},
   {"City", "l"},
   {"Email", "mail"},
   {"Organization Name", "o"},
   {"Organization Unit", "ou"}]
ldap_search_reported
This option defines which search fields should be reported. The format is: [Name, vCard_Name, ...]. Name is the name of a search form field which will be automatically translated by using the translation files (see msgs/*.msg for available words). vCard_Name is the vCard field name defined in the ldap_vcard_map option. The default is: 
  [{"Full Name", "FN"},
   {"Given Name", "FIRST"},
   {"Middle Name", "MIDDLE"},
   {"Family Name", "LAST"},
   {"Nickname", "NICK"},
   {"Birthday", "BDAY"},
   {"Country", "CTRY"},
   {"City", "LOCALITY"},
   {"Email", "EMAIL"},
   {"Organization Name", "ORGNAME"},
   {"Organization Unit", "ORGUNIT"}]
Examples:

3.3.23  mod_version

This module implements Software Version (XEP-0092). Consequently, it answers ejabberd's version when queried.

Options:
show_os
Should the operating system be revealed or not. The default value is true.
iqdisc
This specifies the processing discipline for Software Version (jabber:iq:version) IQ queries (see section 3.3.2).

Chapter 4  Managing an ejabberd server

4.1  Online Configuration and Monitoring

4.1.1  Web Interface

To perform online configuration of ejabberd you need to enable the ejabberd_http listener with the option web_admin (see section 3.1.3). Then you can open http://server:port/admin/ in your favourite web browser. You will be asked to enter the username (the full Jabber ID) and password of an ejabberd user with administrator rights. After authentication you will see a page similar to figure 4.1.
webadmmain.png

Figure 4.1: Top page from the web interface


Here you can edit access restrictions, manage users, create backups, manage the database, enable/disable ports listened for, view server statistics,...

Examples:

4.1.2  ejabberdctl

The ejabberdctl command line script allows to start, stop and perform many other administrative tasks in a local or remote ejabberd server.

When ejabberdctl is executed without any parameter, it displays the available options. If there isn't an ejabberd server running, the available parameters are:
start
Start ejabberd in background mode. This is the default method.
debug
Attach an Erlang shell to an already existing ejabberd server. This allows to execute commands interactively in the ejabberd server.
live
Start ejabberd in live mode: the shell keeps attached to the started server, showing log messages and allowing to execute interactive commands.
If there is an ejabberd server running in the system, ejabberdctl shows all the available commands in that server. The more interesting ones are:
status
Check the status of the ejabberd server.
stop
Stop the ejabberd server which is running in the machine.
reopen-log
If you use a tool to rotate logs, you have to configure it so that this command is executed after each rotation.
backup, restore, install-fallback, dump, load
You can use these commands to create and restore backups.
import-file, import-dir
These options can be used to migrate from other Jabber/XMPP servers. There exist tutorials to migrate from other software to ejabberd.
delete-expired-messages
This option can be used to delete old messages in offline storage. This might be useful when the number of offline messages is very high.
The ejabberdctl script also allows the argument –node NODENAME. This allows to administer a remote node.

The ejabberdctl administration script can be configured in the file ejabberdctl.cfg. This file provides detailed information about each configurable option.

Chapter 5  Securing ejabberd

5.1  Firewall Settings

You need to take the following TCP ports in mind when configuring your firewall:
Port Description
5222 SASL and unencrypted c2s connections.
5223 Obsolete SSL c2s connections.
5269 s2s connections.
4369 Only for clustering (see 7).
port range Only for clustring (see 7). This range is configurable (see 2.4.5).

Chapter 6  Integrating ejabberd with other Instant Messaging servers

6.1  SRV Records

Chapter 7  Clustering

7.1  How it Works

A Jabber domain is served by one or more ejabberd nodes. These nodes can be run on different machines that are connected via a network. They all must have the ability to connect to port 4369 of all another nodes, and must have the same magic cookie (see Erlang/OTP documentation, in other words the file ~ejabberd/.erlang.cookie must be the same on all nodes). This is needed because all nodes exchange information about connected users, s2s connections, registered services, etc...

Each ejabberd node has the following modules:

7.1.1  Router

This module is the main router of Jabber packets on each node. It routes them based on their destination's domains. It uses a global routing table. The domain of the packet's destination is searched in the routing table, and if it is found, the packet is routed to the appropriate process. If not, it is sent to the s2s manager.

7.1.2  Local Router

This module routes packets which have a destination domain equal to one of this server's host names. If the destination JID has a non-empty user part, it is routed to the session manager, otherwise it is processed depending on its content.

7.1.3  Session Manager

This module routes packets to local users. It looks up to which user resource a packet must be sent via a presence table. Then the packet is either routed to the appropriate c2s process, or stored in offline storage, or bounced back.

7.1.4  s2s Manager

This module routes packets to other Jabber servers. First, it checks if an opened s2s connection from the domain of the packet's source to the domain of the packet's destination exists. If that is the case, the s2s manager routes the packet to the process serving this connection, otherwise a new connection is opened.

7.2  Clustering Setup

Suppose you already configured ejabberd on one machine named (first), and you need to setup another one to make an ejabberd cluster. Then do following steps:
  1. Copy ~ejabberd/.erlang.cookie file from first to second.

    (alt) You can also add `-cookie content_of_.erlang.cookie' option to all `erl' commands below.

  2. On second run the following command as the ejabberd daemon user, in the working directory of ejabberd: 
    erl -sname ejabberd \
    -mnesia extra_db_nodes "['ejabberd@first']" \
    -s mnesia
    This will start Mnesia serving the same database as ejabberd@first. You can check this by running the command `mnesia:info().'. You should see a lot of remote tables and a line like the following: 
    running db nodes   = [ejabberd@first, ejabberd@second]


  3. Now run the following in the same `erl' session: 
    mnesia:change_table_copy_type(schema, node(), disc_copies).
    This will create local disc storage for the database.

    (alt) Change storage type of the scheme table to `RAM and disc copy' on the second node via the web interface.

  4. Now you can add replicas of various tables to this node with `mnesia:add_table_copy' or `mnesia:change_table_copy_type' as above (just replace `schema' with another table name and `disc_copies' can be replaced with `ram_copies' or `disc_only_copies').

    Which tables to replicate is very dependant on your needs, you can get some hints from the command `mnesia:info().', by looking at the size of tables and the default storage type for each table on 'first'.

    Replicating a table makes lookups in this table faster on this node. Writing, on the other hand, will be slower. And of course if machine with one of the replicas is down, other replicas will be used.

    Also section 5.3 (Table Fragmentation) of Mnesia User's Guide can be helpful.

    (alt) Same as in previous item, but for other tables.

  5. Run `init:stop().' or just `q().' to exit from the Erlang shell. This probably can take some time if Mnesia has not yet transfered and processed all data it needed from first.

  6. Now run ejabberd on second with almost the same config as on first (you probably do not need to duplicate `acl' and `access' options — they will be taken from first, and mod_muc and mod_irc should be enabled only on one machine in the cluster).
You can repeat these steps for other machines supposed to serve this domain.

7.3  Service Load-Balancing

7.3.1  Components Load-Balancing

7.3.2  Domain Load-Balancing Algorithm

ejabberd includes an algorithm to load balance the components that are plugged on an ejabberd cluster. It means that you can plug one or several instances of the same component on each ejabberd cluster and that the traffic will be automatically distributed.

The default distribution algorithm try to deliver to a local instance of a component. If several local instances are available, one instance is chosen randomly. If no instance is available locally, one instance is chosen randomly among the remote component instances.

If you need a different behaviour, you can change the load balancing behaviour with the option domain_balancing. The syntax of the option is the following: 
 {domain_balancing, "component.example.com", <balancing_criterium>}.
Several balancing criteria are available: If the value corresponding to the criteria is the same, the same component instance in the cluster will be used.

7.3.3  Load-Balancing Buckets

When there is a risk of failure for a given component, domain balancing can cause service trouble. If one component is failing the service will not work correctly unless the sessions are rebalanced.

In this case, it is best to limit the problem to the sessions handled by the failing component. This is what the domain_balancing_component_number option does, making the load balancing algorithm not dynamic, but sticky on a fix number of component instances.

The syntax is the following: 
    {domain_balancing_component_number, "component.example.com", N}

Chapter 8  Debugging

8.1  Watchdog alerts

ejabberd includes a watchdog mechanism to notify administrators in realtime through XMPP when any process consumes too much memory.

To enable the watchdog, add the watchdog_admins option in the config file: 
{watchdog_admins, [``admin@localhost'']}.

Appendix A  Internationalization and Localization

All built-in modules support the xml:lang attribute inside IQ queries. Figure A.1, for example, shows the reply to the following query: 
  <iq id='5'
      to='example.org'
      type='get'
      xml:lang='ru'>
    <query xmlns='http://jabber.org/protocol/disco#items'/>
  </iq>
discorus.png

Figure A.1: Service Discovery when xml:lang='ru'


The web interface also supports the Accept-Language HTTP header (compare figure A.2 with figure 4.1)
webadmmainru.png

Figure A.2: Top page from the web interface with HTTP header `Accept-Language: ru'


Appendix B  Release Notes

Release notes are available from ejabberd Home Page

Appendix C  Acknowledgements

Thanks to all people who contributed to this guide:

Appendix D  Copyright Information

Ejabberd Installation and Operation Guide.
Copyright © 2003 — 2007 Process-one

This document is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This document is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this document; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

This document was translated from LATEX by HEVEA.