xmpp.chapril.org-ejabberd/doc/guide.tex

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        pdftitle=Ejabberd\ Installation\ and\ Operation\ Guide,pdfauthor=Alexey\
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\usepackage{makeidx}
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%% Various
\newcommand{\bracehack}{\def\{{\char"7B}\def\}{\char"7D}}
\newcommand{\titem}[1]{\item[\bracehack\texttt{#1}]}
\newcommand{\ns}[1]{\texttt{#1}}
\newcommand{\jid}[1]{\texttt{#1}}
\newcommand{\option}[1]{\texttt{#1}}
\newcommand{\poption}[1]{{\bracehack\texttt{#1}}}
\newcommand{\node}[1]{\texttt{#1}}
\newcommand{\term}[1]{\texttt{#1}}
\newcommand{\shell}[1]{\texttt{#1}}
\newcommand{\ejabberd}{\texttt{ejabberd}}
\newcommand{\Jabber}{Jabber}

%% Modules
\newcommand{\module}[1]{\texttt{#1}}
\newcommand{\modadhoc}{\module{mod\_adhoc}}
\newcommand{\modannounce}{\module{mod\_announce}}
\newcommand{\modconfigure}{\module{mod\_configure}}
\newcommand{\moddisco}{\module{mod\_disco}}
\newcommand{\modecho}{\module{mod\_echo}}
\newcommand{\modirc}{\module{mod\_irc}}
\newcommand{\modlast}{\module{mod\_last}}
\newcommand{\modlastodbc}{\module{mod\_last\_odbc}}
\newcommand{\modmuc}{\module{mod\_muc}}
\newcommand{\modmuclog}{\module{mod\_muc\_log}}
\newcommand{\modoffline}{\module{mod\_offline}}
\newcommand{\modofflineodbc}{\module{mod\_offline\_odbc}}
\newcommand{\modprivacy}{\module{mod\_privacy}}
\newcommand{\modprivate}{\module{mod\_private}}
\newcommand{\modpubsub}{\module{mod\_pubsub}}
\newcommand{\modregister}{\module{mod\_register}}
\newcommand{\modroster}{\module{mod\_roster}}
\newcommand{\modrosterodbc}{\module{mod\_roster\_odbc}}
\newcommand{\modservicelog}{\module{mod\_service\_log}}
\newcommand{\modsharedroster}{\module{mod\_shared\_roster}}
\newcommand{\modstats}{\module{mod\_stats}}
\newcommand{\modtime}{\module{mod\_time}}
\newcommand{\modvcard}{\module{mod\_vcard}}
\newcommand{\modvcardldap}{\module{mod\_vcard\_ldap}}
\newcommand{\modvcardodbc}{\module{mod\_vcard\_odbc}}
\newcommand{\modversion}{\module{mod\_version}}

%% Common options
\newcommand{\iqdiscitem}[1]{\titem{iqdisc} \ind{options!iqdisc}This specifies 
the processing discipline for #1 IQ queries
(see section~\ref{sec:modiqdiscoption}).}
\newcommand{\hostitem}[1]{
  \titem{hosts} \ind{options!hosts} This option defines the hostnames of the
  service (see section~\ref{sec:modhostsoption}). If neither \texttt{hosts} nor
  the old \texttt{host} is present, the prefix ``\jid{#1.}'' is added to all
  \ejabberd{} hostnames.
}

%% Title page
\include{version}
\title{Ejabberd \version\ Installation and Operation Guide}
\author{Alexey Shchepin \\
  \ahrefurl{mailto:alexey@sevcom.net} \\
  \ahrefurl{xmpp:aleksey@jabber.ru}}

%% Options
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%% Footnotes
\begin{latexonly}
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\gdef\ahrefurl#1{\href{#1}{\texttt{#1}}}
\gdef\footahref#1#2{#2\footnote{\href{#1}{\texttt{#1}}}}
\end{latexonly}
\newcommand{\tjepref}[2]{\footahref{http://www.jabber.org/jeps/jep-#1.html}{#2}}
\newcommand{\jepref}[1]{\tjepref{#1}{JEP-#1}}

\begin{document}

\label{sec:titlepage}
\begin{titlepage}
  \maketitle{}

  \begin{center}
  {\insscaleimg{\logoscale}{logo.png}
    \par
  }
  \end{center}

  \begin{quotation}\textit{I can thoroughly recommend ejabberd for ease of setup --
  Kevin Smith, Current maintainer of the Psi project}\end{quotation}

\end{titlepage}

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\tableofcontents{}

% Input introduction.tex
\input{introduction}

\section{Installation from Source}
\label{sec:installation}
\ind{installation}

\subsection{Installation Requirements}
\label{sec:installreq}

\subsubsection{``Unix-like'' operating systems}
\label{sec:installrequnix}
\ind{installation!requirements for ``Unix-like'' operating systems}

To compile \ejabberd{} on a ``Unix-like'' operating system, you need:
\begin{itemize}
\item GNU Make;
\item GCC;
\item libexpat 1.95 or higher;
\item Erlang/OTP R9C-2 or higher;
\item OpenSSL 0.9.6 or higher (optional).
\item Zlib 1.2.3 or higher (optional).
\item GNU Iconv 1.8 or higher (optional, not needed at all on systems with GNU libc).
\end{itemize}

\subsubsection{Windows}
\label{sec:installreqwin}
\ind{installation!requirements for Windows}

To compile \ejabberd{} on a Windows flavour, you need:
\begin{itemize}
\item MS Visual C++ 6.0 Compiler
\item \footahref{http://erlang.org/download.html}{Erlang/OTP R9C-2 or higher}
\item \footahref{http://sourceforge.net/project/showfiles.php?group\_id=10127\&package\_id=11277}{Expat 1.95.7 or higher}
\item
\footahref{http://www.gnu.org/software/libiconv/}{GNU Iconv 1.9.1}
(optional)
\item \footahref{http://www.slproweb.com/products/Win32OpenSSL.html}{Shining Light OpenSSL}
(to enable SSL connections)
\item \footahref{http://www.zlib.net/}{Zlib 1.2.3 or higher}
\end{itemize}

\subsection{Obtaining \ejabberd{}}
\label{sec:obtaining}

\ind{download}
Released versions of \ejabberd{} can be obtained from \\
\ahrefurl{http://www.process-one.net/en/projects/ejabberd/download.html}.

\ind{Subversion repository}
The latest development version can be retrieved from the Subversion repository\@.
\begin{verbatim}
  svn co http://svn.process-one.net/ejabberd/trunk ejabberd
\end{verbatim}

\subsection{Compilation}
\label{sec:compilation}
\ind{compilation}

\subsubsection{``Unix-like'' operating systems}
\label{sec:compilationunix}
\ind{compilation!on ``Unix-like'' operating systems}

Compile \ejabberd{} on a ``Unix-like'' operating system by executing:

\begin{verbatim}
  ./configure
  make
  su
  make install
\end{verbatim}

These commands will:
\begin{itemize}
\item install \ejabberd{} into the directory \verb|/var/lib/ejabberd|,
\item install the configuration file into \verb|/etc/ejabberd|,
\item create a directory called \verb|/var/log/ejabberd| to store log files.
\end{itemize}

\subsubsection{Windows}
\label{sec:compilationwin}
\ind{compilation!on Windows}

\begin{itemize}
\item Install Erlang emulator (for example, into \verb|C:\Program Files\erl5.3|).
\item Install Expat library into \verb|C:\Program Files\Expat-1.95.7|
  directory.

  Copy file \verb|C:\Program Files\Expat-1.95.7\Libs\libexpat.dll|
  to your Windows system directory (for example, \verb|C:\WINNT| or
  \verb|C:\WINNT\System32|)
\item Build and install the Iconv library into the directory
  \verb|C:\Program Files\iconv-1.9.1|.

  Copy file \verb|C:\Program Files\iconv-1.9.1\bin\iconv.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
  \verb|C:\Program Files\Expat-1.95.7\Libs| and
  \verb|C:\Program Files\iconv-1.9.1\bin| to the \verb|PATH| environment
  variable.
\item While in the directory \verb|ejabberd\src| run:
\begin{verbatim}
configure.bat
nmake -f Makefile.win32
\end{verbatim}
\item Edit the file \verb|ejabberd\src\ejabberd.cfg| and run
\begin{verbatim}
werl -s ejabberd -name ejabberd
\end{verbatim}
\end{itemize}

\subsection{Starting}
\label{sec:starting}
\ind{starting}

Execute the following command to start \ejabberd{}:
\begin{verbatim}
  erl -pa /var/lib/ejabberd/ebin -name ejabberd -s ejabberd
\end{verbatim}
or
\begin{verbatim}
  erl -pa /var/lib/ejabberd/ebin -sname ejabberd -s ejabberd
\end{verbatim}
In the latter case the Erlang node will be identified using only the first part
of the host name, i.\,e. other Erlang nodes outside this domain can't contact
this node.

Note that when using the above command, \ejabberd{} will search for the
configuration file in the current directory and will use the current directory
for storing its user database and for logging.

To specify the path to the configuration file, the log files and the Mnesia
database directory, you may use the following command:
\begin{verbatim}
  erl -pa /var/lib/ejabberd/ebin \
      -sname ejabberd \
      -s ejabberd \
      -ejabberd config \"/etc/ejabberd/ejabberd.cfg\" \
                log_path \"/var/log/ejabberd/ejabberd.log\" \
      -sasl sasl_error_logger \{file,\"/var/log/ejabberd/sasl.log\"\} \
      -mnesia dir \"/var/lib/ejabberd/spool\"
\end{verbatim}

You can find other useful options in the Erlang manual page
(\shell{erl -man erl}).

To use more than 1024 connections, you should set the environment variable
\verb|ERL_MAX_PORTS|:
\begin{verbatim}
  export ERL_MAX_PORTS=32000
\end{verbatim}
Note that with this value, \ejabberd{} will use more memory (approximately 6\,MB
more).

To reduce memory usage, you may set the environment variable
\verb|ERL_FULLSWEEP_AFTER|:
\begin{verbatim}
  export ERL_FULLSWEEP_AFTER=0
\end{verbatim}
But in this case \ejabberd{} can start to work slower.


\section{Configuration}
\label{sec:configuration}

\subsection{Initial Configuration}
\label{sec:initconfig}
\ind{configuration file}

The configuration file will be loaded the first time you start \ejabberd{}. The
content from this file will be parsed and stored in a 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. The
configuration file contains a sequence of Erlang terms. Lines beginning with a
\term{`\%'} 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:
\begin{verbatim}
  override_global.
  override_local.
  override_acls.
\end{verbatim}
With these lines the old global options, local options and ACLs will be removed
before new ones are added.

\subsubsection{Host Names}
\label{sec:confighostname}
\ind{options!hosts}\ind{host names}

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

Examples:
\begin{itemize}
\item Serving one domain:
\begin{itemize}
\item \begin{verbatim}
  {hosts, ["example.org"]}.
\end{verbatim}
\item Backwards compatibility with older \ejabberd{} versions can be retained
  with:
  \begin{verbatim}
  {host, "example.org"}.
\end{verbatim}
\end{itemize}
\item Serving two domains:
\begin{verbatim}
  {hosts, ["example.net", "example.com"]}.
\end{verbatim}
\end{itemize}

\subsubsection{Default Language}
\label{sec:configlanguage}
\ind{options!language}\ind{language}

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

Examples:
\begin{itemize}
\item To set Russian as default language:
\begin{verbatim}
  {language, "ru"}.
\end{verbatim}
\item To set Spanish as default language:
\begin{verbatim}
  {language, "es"}.
\end{verbatim}
\end{itemize}

\subsubsection{Access Rules}
\label{sec:configaccess}
\ind{options!acl}\ind{access rules}\ind{ACL}\ind{Access Control List}

Access control in \ejabberd{} is performed via Access Control Lists (ACLs). The
declarations of ACLs in the configuration file have the following syntax:
\begin{verbatim}
  {acl, <aclname>, {<acltype>, ...}}.
\end{verbatim}

\term{<acltype>} can be one of the following:
\begin{description}
\titem{all} Matches all JIDs. Example:
\begin{verbatim}
{acl, all, all}.
\end{verbatim}
\titem{\{user, <username>\}} Matches the user with the name
  \term{<username>} at the first virtual host. Example:
\begin{verbatim}
{acl, admin, {user, "yozhik"}}.
\end{verbatim}
\titem{\{user, <username>, <server>\}} Matches the user with the JID
  \term{<username>@<server>} and any resource. Example:
\begin{verbatim}
{acl, admin, {user, "yozhik", "example.org"}}.
\end{verbatim}
\titem{\{server, <server>\}} Matches any JID from server
  \term{<server>}. Example:
\begin{verbatim}
{acl, exampleorg, {server, "example.org"}}.
\end{verbatim}
\titem{\{user\_regexp, <regexp>\}} Matches any local user with a name that
  matches \term{<regexp>} at the first virtual host. Example:
\begin{verbatim}
{acl, tests, {user, "^test[0-9]*$"}}.
\end{verbatim}
%$
\titem{\{user\_regexp, <regexp>, <server>\}} Matches any user with a name
  that matches \term{<regexp>} at server \term{<server>}. Example:
\begin{verbatim}
{acl, tests, {user, "^test", "example.org"}}.
\end{verbatim}
\titem{\{server\_regexp, <regexp>\}} Matches any JID from the server that
  matches \term{<regexp>}. Example:
\begin{verbatim}
{acl, icq, {server, "^icq\\."}}.
\end{verbatim}
\titem{\{node\_regexp, <user\_regexp>, <server\_regexp>\}} Matches any user
  with a name that matches \term{<user\_regexp>} at any server that matches
  \term{<server\_regexp>}. Example:
\begin{verbatim}
{acl, yohzik, {node_regexp, "^yohzik$", "^example.(com|org)$"}}.
\end{verbatim}
\titem{\{user\_glob, <glob>\}}
\titem{\{user\_glob, <glob>, <server>\}}
\titem{\{server\_glob, <glob>\}}
\titem{\{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:
  \begin{description}
  \titem{*} matches any string including the null string.
  \titem{?} matches any single character.
  \titem{[...]} matches any of the enclosed characters. Character
    ranges are specified by a pair of characters separated by a \term{`-'}.
    If the first character after \term{`['} is a \term{`!'}, any
    character not enclosed is matched.
  \end{description}
\end{description}

The following ACLs are pre-defined:
\begin{description}
\titem{all} Matches any JID.
\titem{none} Matches no JID.
\end{description}

An entry allowing or denying access to different services looks similar to
this:
\begin{verbatim}
  {access, <accessname>, [{allow, <aclname>},
                          {deny, <aclname>},
                          ...
                         ]}.
\end{verbatim}
When a JID is checked to have access to \term{<accessname>}, the server
sequentially checks if that JID mathes 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 ``\term{deny}'' is returned.

Example:
\begin{verbatim}
  {access, configure, [{allow, admin}]}.
  {access, something, [{deny, badmans},
                       {allow, all}]}.
\end{verbatim}

The following access rules are pre-defined:
\begin{description}
\titem{all} Always returns ``\term{allow}''
\titem{none} Always returns ``\term{deny}''
\end{description}

\subsubsection{Shapers}
\label{sec:configshaper}
\ind{options!shaper}\ind{options!maxrate}\ind{shapers}\ind{maxrate}\ind{traffic speed}

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

Examples:
\begin{itemize}
\item To define a shaper named ``\term{normal}'' with traffic speed limited to
1,000\,bytes/second:
\begin{verbatim}
  {shaper, normal, {maxrate, 1000}}.
\end{verbatim}
\item To define a shaper named ``\term{fast}'' with traffic speed limited to
50,000\,bytes/second:
\begin{verbatim}
  {shaper, fast, {maxrate, 50000}}.
\end{verbatim}
\end{itemize}

\subsubsection{Limitation of the number of opened sessions}
\label{sec:configmaxsessions}
\ind{options!max\_user\_sessions}

This option specifies the maximum number of sessions (authenticated
connections) per user. If a user tries to open more than the maximum number of
allowed sessions, with different resources, the first opened session will be
disconnected. The error ``\term{session replaced}'' is send to the
disconnected session. This value is either a number or \term{infinity}.  For
example \verb|{max\_user\_sessions, 10}|.  The default value is \term{10}.

This option can be define per virtual host. See section~\ref{sec:configvirtualhost}.

\subsubsection{Listened Sockets}
\label{sec:configlistened}
\ind{options!listen}

The option \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:
\begin{itemize}
\item Port number.
\item Module that serves this port.
\item Options to this module.
\end{itemize}

\ind{modules!ejabberd\_c2s}\ind{modules!ejabberd\_s2s\_in}\ind{modules!ejabberd\_service}\ind{modules!ejabberd\_http}\ind{protocols!JEP-0114: Jabber Component Protocol}
Currently next modules are implemented:
\begin{table}[H]
  \centering
  \def\arraystretch{1.4}
  \begin{tabular}{|l|l|p{87mm}|}
  \hline \texttt{ejabberd\_c2s}& Description& Handles c2s connections.\\
    \cline{2-3} & Options& \texttt{access}, \texttt{certfile}, \texttt{inet6},
    \texttt{ip}, \texttt{max\_stanza\_size}, \texttt{shaper}, \texttt{ssl},
    \texttt{tls}, \texttt{starttls}, \texttt{starttls\_required},
    \texttt{zlib}\\
  \hline \texttt{ejabberd\_s2s\_in}& Description& Handles incoming s2s
  connections.\\
    \cline{2-3} & Options& \texttt{inet6}, \texttt{ip},
    \texttt{max\_stanza\_size}\\
  \hline \texttt{ejabberd\_service}& Description& Interacts with external
  components (*).\\
    \cline{2-3} & Options& \texttt{access}, \texttt{hosts}, \texttt{inet6},
    \texttt{ip}, \texttt{shaper}\\
  \hline \texttt{ejabberd\_http}& Description& Handles incoming HTTP
  connections.\\
    \cline{2-3} & Options& \texttt{certfile}, \texttt{http\_poll},
    \texttt{inet6}, \texttt{ip}, \texttt{tls}, \texttt{web\_admin}\\
  \hline
  \end{tabular}
\end{table}

(*) The mechanism for \footahref{http://ejabberd.jabber.ru/tutorials-transports}{external components} is defined in Jabber Component Protocol (\jepref{0114}).

The following options are available:
\begin{description}
  \titem{\{access, <access rule>\}} \ind{options!access}This option defines
    access to the port. The default value is ``\term{all}''.
  \titem{\{certfile, Path\}} Path to a file containing the SSL certificate.
  \titem{\{hosts, [Hostnames], [HostOptions]\}} \ind{options!hosts}This option
    defines one or more hostnames of connected services and enables you to
    specify additional options including \poption{\{password, Secret\}}.
  \titem{http\_poll} \ind{options!http\_poll}\ind{protocols!JEP-0025: HTTP Polling}\ind{JWChat}\ind{web-based Jabber client}
    This option enables HTTP Polling (\jepref{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
    \verb|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
    \footahref{http://jwchat.sourceforge.net/}{JWChat} (there is a tutorial to
    \footahref{http://ejabberd.jabber.ru/jwchat}{install JWChat} with
    instructions for \ejabberd{}).
  \titem{inet6} \ind{options!inet6}\ind{IPv6}Set up the socket for IPv6.
  \titem{\{ip, IPAddress\}} \ind{options!ip}This option specifies which network
    interface to listen for. For example \verb|{ip, {192, 168, 1, 1}}|.
  \titem{\{max\_stanza\_size, Size\}} \ind{options!max\_stanza\_size}This
    option specifies an approximate maximal size in bytes of XML stanzas.
    For example \verb|{max\_stanza\_size, 65536}|.  The default value
    is ``\term{infinity}''.
  \titem{\{shaper, <access rule>\}} \ind{options!shaper}This option defines a
    shaper for the port (see section~\ref{sec:configshaper}). The default value
    is ``\term{none}''.
  \titem{ssl} \ind{options!ssl}\ind{SSL}This option specifies that traffic on
    the port will be encrypted using SSL. You should also set the
    \option{certfile} option. It is recommended to use the \term{tls} option
    instead.
  \titem{starttls} \ind{options!starttls}\ind{modules!STARTTLS}This option
    specifies that STARTTLS encryption is available on connections to the port.
    You should also set the \option{certfile} option.
  \titem{starttls\_required} \ind{options!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
    \option{certfile} option.
  \titem{tls} \ind{options!tls}\ind{TLS}This option specifies that traffic on
    the port will be encrypted using SSL immediately after connecting. You
    should also set the \option{certfile} option.
  \titem{zlib} \ind{options!zlib}\ind{protocols!JEP-0138: Stream Compression}\ind{Zlib}This
    option specifies that Zlib stream compression (as defined in \jepref{0138})
    is available on connections to the port. Client cannot use stream compression and
    stream encryption simultaneously, so if you specify both \option{tls} (or \option{ssl})
    and \option{zlib} the latter option will not affect connection at all.
  \titem{web\_admin} \ind{options!web\_admin}\ind{web interface}This option
    enables the web interface for \ejabberd{} administration which is available
    at \verb|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.
\end{description}

Also the following global options are available for s2s connections:
\begin{description}
  \titem{\{s2s\_use\_starttls, true|false\}}
  \ind{options!s2s\_use\_starttls}This option defines whether to use STARTTLS
  for s2s connections.
  \titem{\{s2s\_certfile, Path\}} \ind{options!s2s\_certificate}Path to the
  file containing the SSL certificate.
  \titem{\{domain\_certfile, Domain, Path\}} \ind{options!domain\_certfile}Path
  to the file containing the SSL certificate for the specified domain.
\end{description}

For instance, the following configuration defines that:
\begin{itemize}
\item c2s connections are listened for on port 5222 and 5223 (SSL) and denied
  for the user ``\term{bad}''
\item s2s connections are listened for on port 5269 with STARTTLS for secured
  traffic enabled.
\item Port 5280 is serving the web interface and the HTTP Polling service. Note
  that it is also possible to serve them on different ports. The second
  example in section~\ref{sec:webadm} shows how exactly this can be done.
\item All users except for the administrators have a traffic of limit 
  1,000\,Bytes/second
\item \ind{transports!AIM}The
  \footahref{http://ejabberd.jabber.ru/pyaimt}{AIM transport}
  \jid{aim.example.org} is connected to port 5233 with password
  ``\term{aimsecret}''
\item \ind{transports!ICQ}The ICQ transport JIT (\jid{icq.example.org} and
  \jid{sms.example.org}) is connected to port 5234 with password
  ``\term{jitsecret}''
\item \ind{transports!MSN}The
  \footahref{http://ejabberd.jabber.ru/pymsnt}{MSN transport}
  \jid{msn.example.org} is connected to port 5235 with password
  ``\term{msnsecret}''
\item \ind{transports!Yahoo}The
  \footahref{http://ejabberd.jabber.ru/yahoo-transport-2}{Yahoo! transport}
  \jid{yahoo.example.org} is connected to port 5236 with password
  ``\term{yahoosecret}''
\item \ind{transports!Gadu-Gadu}The \footahref{http://ejabberd.jabber.ru/jabber-gg-transport}{Gadu-Gadu transport} \jid{gg.example.org} is
  connected to port 5237 with password ``\term{ggsecret}''
\item \ind{transports!email notifier}The
  \footahref{http://ejabberd.jabber.ru/jmc}{Jabber Mail Component}
  \jid{jmc.example.org} is connected to port 5238 with password
  ``\term{jmcsecret}''
\end{itemize}
\begin{verbatim}
  {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"}]}]}
   ]
  }.
  {s2s_use_starttls, true}.
  {s2s_certfile, "/path/to/ssl.pem"}.
\end{verbatim}
Note, that for \ind{jabberd 1.4}jabberd 1.4- or \ind{WPJabber}WPJabber-based
services you have to make the transports log and do \ind{XDB}XDB by themselves:
\begin{verbatim}
  <!--
     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>
\end{verbatim}

\subsubsection{Modules}
\label{sec:configmodules}
\ind{modules}

The option \term{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. Read section~\ref{sec:modules} for detailed information about modules.

Examples:
\begin{itemize}
\item In this simple example, only the module \modecho{} is loaded and no
  options are specified between square brackets:
  \begin{verbatim}
  {modules,
   [{mod_echo,      []}
   ]}.
\end{verbatim}
\item The second example is also simple: the modules \modecho{}, \modtime{}, and
  \modversion{} are loaded without options. Remark that, besides the last entry,
  all entries end with a comma:
  \begin{verbatim}
  {modules,
   [{mod_echo,      []},
    {mod_time,      []},
    {mod_version,   []}
   ]}.
\end{verbatim}
\end{itemize}

\subsubsection{Virtual Hosting}
\label{sec:configvirtualhost}
\ind{virtual hosting}\ind{virtual hosts}

Options can be defined separately for every virtual host using the
\term{host\_config} option.\ind{options!host\_config} It has the following
syntax:
\begin{verbatim}
  {host_config, <hostname>, [<option>, <option>, ...]}.
\end{verbatim}

Examples:
\begin{itemize}
\item Domain \jid{example.net} is using the internal authentication method while
  domain \jid{example.com} is using the \ind{LDAP}LDAP server running on the domain
  \jid{localhost} to perform authentication:
\begin{verbatim}
{host_config, "example.net", [{auth_method, internal}]}.

{host_config, "example.com", [{auth_method, ldap},
                              {ldap_servers, ["localhost"]},
                              {ldap_uidattr, "uid"},
                              {ldap_rootdn, "dc=localdomain"},
                              {ldap_rootdn, "dc=example,dc=com"},
                              {ldap_password, ""}]}.
\end{verbatim}
\item Domain \jid{example.net} is using \ind{ODBC}ODBC to perform authentication
  while domain \jid{example.com} is using the LDAP servers running on the domains
  \jid{localhost} and \jid{otherhost}:
\begin{verbatim}
{host_config, "example.net", [{auth_method, odbc},
                              {odbc_server, "DSN=ejabberd;UID=ejabberd;PWD=ejabberd"}]}.

{host_config, "example.com", [{auth_method, ldap},
                              {ldap_servers, ["localhost", "otherhost"]},
                              {ldap_uidattr, "uid"},
                              {ldap_rootdn, "dc=localdomain"},
                              {ldap_rootdn, "dc=example,dc=com"},
                              {ldap_password, ""}]}.
\end{verbatim}
\end{itemize}

\subsubsection{SASL anonymous and anonymous login}
\label{sec:configsaslanonymous}
\ind{sasl anonymous}\ind{anonymous login}

The configuration of the anonymous mode can be done with three
\term{host\_config} parameters:

\begin{itemize} 
\item \term{auth\_method}: This value is used for defining the authentication method:
internal, odbc, ldap, external). You now have a special extra option to enable
anonymous mode: anonymous.

\item \term{allow\_multiple\_connections}: This option can be either true or false and
is only used when the anonymous mode is enabled. Setting it to true means that
the same username will be able to be taken several time in anonymous login
mode if different resource are used to connect. This option is only useful in
very special cases. It defaults to false.

\item \term{anonymous\_protocol}: This option can take three values:
  \term{sasl\_anon}, \term{login\_anon} or both.  \term{sasl\_anon} means that
  SASL anonymous mode is enabled.  \term{login\_anon} means that anonymous
  login mode is enabled. both means that SASL anonymous and login anonymous are
  enabled.
\end{itemize}

Those options are defined for each virtual host with the \term{host\_config}
parameter (see section~\ref{sec:configvirtualhost}).

Examples:
\begin{itemize}
\item To enable anonymous login on a virtual host:
\begin{verbatim}
{host_config, "public.example.org", [{auth_method, anonymous},
                                     {anonymous_protocol, login_anon}]}.
\end{verbatim}
\item To enable anonymous login and internal authentication on a virtual host:
\begin{verbatim}
{host_config, "public.example.org", [{auth_method, [anonymous,internal]},
                                     {anonymous_protocol, login_anon}]}.
\end{verbatim}
\item To enable SASL anonymous on a virtual host:
\begin{verbatim}
{host_config, "public.example.org", [{auth_method, [anonymous]},
                                     {anonymous_protocol, sasl_anon}]}.
\end{verbatim}
\item To enable SASL anonymous and anonymous login on a virtual host:
\begin{verbatim}
{host_config, "public.example.org", [{auth_method, [anonymous]},
                                     {anonymous_protocol, both}]}.
\end{verbatim}
\item To enable SASL anonymous, anonymous login and internal authentication on
a virtual host:
\begin{verbatim}
{host_config, "public.example.org", [{auth_method, [anonymous,internal]},
                                     {anonymous_protocol, both}]}.
\end{verbatim}
\end{itemize}

A detailled tutorial on SASL anonymous and anonymous login support is
available from:
\ahrefurl{http://support.process-one.net/doc/display/MESSENGER/Anonymous+users+support}

\subsection{Relational Database Support}
\label{sec:relationaldatabase}

\subsubsection{Authentication against a relational database}
\label{sec:relationaldatabaseauth}

ejabberd use its internal Mnesia database as a default. It is however possible
to use relational database to store persistant, long-living data. When
switching the \term{auth\_method} from internal to \term{odbc}, you are
telling ejabberd to use a relational database for authentication. Different
\term{auth\_method} values can be used for different virtual hosts in the
system.

The option value name be misleading, as the method name is use both for access
to relational database through ODBC or through the native interface. In any
case, the first step is to define the odbc \term{auth\_method}. For example:
\begin{verbatim}
{host_config, "public.example.org", [{auth_method, [odbc]}]}.
\end{verbatim}

The actual database access is defined in the option \term{odbc\_server}. Its
value is use 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 \term{odbc\_server} parameter. For example:
\begin{verbatim}
{odbc_server, "DSN=database;UID=ejabberd;PWD=password"}.
\end{verbatim}

To use the native PostgreSQL interface, you can pass a tuple of the following form as
parameter:
\begin{verbatim}
{pgsql, "Server", "Database", "Username", "Password"}
\end{verbatim}

\term{pgsql} is a keyword that should be kept as is. For example:
\begin{verbatim}
{odbc_server, {pgsql, "localhost", "database", "ejabberd", "password"}}.
\end{verbatim}

Note that you need to install the Erlang PgSQL library first. This library is
available from Sourceforge: \ahrefurl{http://cvs.sourceforge.net/viewcvs.py/jungerl/jungerl/lib/pgsql/}

To use the native MySQL interface, the same tuple should be passed, except
that you now have to use the \term{mysql} keyword instead of the \term{pgsql}
keyword:
\begin{verbatim}
{mysql, "Server", "Database", "Username", "Password"}
\end{verbatim}

\term{mysql} is a keyword that should be kept as is. For example:
\begin{verbatim}
{odbc_server, {mysql, "localhost", "test", "root", "password"}}.
\end{verbatim}

Note that you need to install the Erlang MySQL library first. This library is
directly available from Process-one website: \ahrefurl{http://support.process-one.net/doc/display/CONTRIBS/Yxa}

A detailled tutorial to set-up \ejabberd{} using the native MySQL interface is
available from: \ahrefurl{http://support.process-one.net/doc/display/MESSENGER/Using+ejabberd+with+MySQL+native+driver}

\subsubsection{Relational database for other modules}
\label{sec:relationaldatabaseextra}

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
\term{\_odbc} suffix in \ejabberd{} config file. You can use a relational
database for the following data:

\begin{itemize}
\item Last connection date and time: Use \term{mod\_last\_odbc} instead of
  \term{mod\_last}.
\item Offline messages: Use \term{mod\_offline\_odbc} instead of
  \term{mod\_offline}.
\item Rosters: Use \term{mod\_roster\_odbc} instead of \term{mod\_roster}.
\item Users' VCARD: Use \term{mod\_vcard\_odbc} instead of \term{mod\_vcard}.
\end{itemize}

\subsection{Creating an Initial Administrator}
\label{sec:initialadmin}

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:
\begin{enumerate}
\item Register an account on your \ejabberd{} deployment. An account can be
  created in two ways:
  \begin{enumerate}
  \item Using the tool \term{ejabberdctl}\ind{ejabberdctl} (see
    section~\ref{sec:ejabberdctl}):
    \begin{verbatim}
% ejabberdctl node@host register admin example.org password
\end{verbatim} 
  \item Using In-Band Registration (see section~\ref{sec:modregister}): you can
    use a \Jabber{} client to register an account.
  \end{enumerate}
\item 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 seperate acl entry is needed for each administrator.
  \begin{verbatim}
  {acl, admins, {user, "admin", "example.org"}}.
  {access, configure, [{allow, admins}]}.
\end{verbatim} 
\item Restart \ejabberd{} to load the new configuration.
\item Open the web interface (\verb|http://server:port/admin/|) in your
  favourite browser. Make sure to enter the \emph{full} JID as username (in this
  example: \jid{admin@example.org}. The reason that you also need to enter the
  suffix, is because \ejabberd{}'s virtual hosting support.
\end{enumerate}

\subsection{Online Configuration and Monitoring}
\label{sec:onlineconfig}

\subsubsection{Web Interface}
\label{sec:webadm}
\ind{web interface}

To perform online configuration of \ejabberd{} you need to enable the
\term{ejabberd\_http} listener with the option \term{web\_admin} (see
section~\ref{sec:configlistened}). Then you can open 
\verb|http://server:port/admin/| in your favourite web browser. You
will be asked to enter the username (the \emph{full} \Jabber{} ID) and password
of an \ejabberd{} user with administrator rights. After authentication
you will see a page similar to figure~\ref{fig:webadmmain}.

\begin{figure}[htbp]
  \centering
  \insimg{webadmmain.png}
  \caption{Top page from the web interface}
  \label{fig:webadmmain}
\end{figure}
Here you can edit access restrictions, manage users, create backups,
manage the database, enable/disable ports listened for, view server
statistics,\ldots

Examples:
\begin{itemize}
\item You can serve the web interface on the same port as the
  \ind{protocols!JEP-0025: HTTP Polling}HTTP Polling interface. In this example
  you should point your web browser to \verb|http://example.org:5280/admin/| to
  administer all virtual hosts or to
  \verb|http://example.org:5280/admin/server/example.com/| to administer only
  the virtual host \jid{example.com}. Before you get access to the web interface
  you need to enter as username, the JID and password from a registered user
  that is allowed to configure \ejabberd{}. In this example you can enter as
  username ``\jid{admin@example.net}'' to administer all virtual hosts (first
  URL). If you log in with ``\jid{admin@example.com}'' on \\
  \verb|http://example.org:5280/admin/server/example.com/| you can only
  administer the virtual host \jid{example.com}.
  \begin{verbatim}
  ...
  {acl, admins, {user, "admin", "example.net"}}.
  {host_config, "example.com", [{acl, admins, {user, "admin", "example.com"}}]}.
  {access, configure, [{allow, admins}]}.
  ...
  {hosts, ["example.org"]}.
  ...
  {listen,
   [...
    {5280, ejabberd_http, [http_poll, web_admin]},
    ...
   ]
  }.
\end{verbatim}
\item For security reasons, you can serve the web interface on a secured
  connection, on a port differing from the HTTP Polling interface, and bind it
  to the internal LAN IP. The web interface will be accessible by pointing your
  web browser to \verb|https://192.168.1.1:5280/admin/|:
  \begin{verbatim}
  ...
  {hosts, ["example.org"]}.
  ...
  {listen,
   [...
    {5270, ejabberd_http,    [http_poll]},
    {5280, ejabberd_http,    [web_admin, {ip, {192, 168, 1, 1}},
                              tls, {certfile, "/usr/local/etc/server.pem"}]},
    ...
   ]
  }.
\end{verbatim}
\end{itemize}

\subsubsection{\term{ejabberdctl}}
\label{sec:ejabberdctl}

It is possible to do some administration operations using the command
line tool \term{ejabberdctl}. You can list all available options by
running \term{ejabberdctl} without arguments:
\begin{verbatim}
% ejabberdctl
Usage: ejabberdctl node command

Available commands:
  status                        get ejabberd status
  stop                          stop ejabberd
  restart                       restart ejabberd
  reopen-log                    reopen log file
  register user server password register a user
  unregister user server        unregister a user
  backup file                   store a database backup to file
  restore file                  restore a database backup from file
  install-fallback file         install a database fallback from file
  dump file                     dump a database to a text file
  load file                     restore a database from a text file
  import-file file              import user data from jabberd 1.4 spool file
  import-dir dir                import user data from jabberd 1.4 spool directory
  registered-users              list all registered users
  delete-expired-messages       delete expired offline messages from database

Example:
  ejabberdctl ejabberd@host restart
\end{verbatim}

Additional information:
\begin{description}
\titem{reopen-log } If you use a tool to rotate logs, you have to configure it
  so that this command is executed after each rotation.
\titem {backup, restore, install-fallback, dump, load} You can use these
  commands to create and restore backups. 
%%More information about backuping can
%%  be found in section~\ref{sec:backup}.
\titem{import-file, import-dir} \ind{migration!from jabberd 1.4}\ind{migration!from jabberd2}
  These options can be used to migrate from other \Jabber{}/XMPP servers. There
  exist tutorials to \footahref{http://ejabberd.jabber.ru/jabberd1-to-ejabberd}{migrate from jabberd 1.4}
  and to \footahref{http://ejabberd.jabber.ru/jabberd2-to-ejabberd}{migrate from jabberd2}.
\titem{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.
\end{description}


\section{Firewall Settings}
\label{sec:firewall}
\ind{firewall}\ind{ports}\ind{SASL}\ind{TLS}\ind{clustering!ports}

You need to take the following TCP ports in mind when configuring your firewall:
\begin{table}[H]
  \centering
  \begin{tabular}{|l|l|}
    \hline Port& Description\\
    \hline \hline 5222& SASL and unencrypted c2s connections.\\
    \hline 5223& Obsolete SSL c2s connections.\\
    \hline 5269& s2s connections.\\
    \hline 4369& Only for clustering (see~\ref{sec:clustering}).\\
    \hline port range& Only for clustring (see~\ref{sec:clustering}). This range
    is configurable (see~\ref{sec:starting}).\\
    \hline
  \end{tabular}
\end{table}


\section{SRV Records}
\label{sec:srv}
\ind{SRV Records}\ind{clustering!SRV Records}

\begin{itemize}
\item General information:
  \footahref{http://en.wikipedia.org/wiki/SRV\_record}{SRV record}
\item Practical information:
  \footahref{http://jabberd.jabberstudio.org/2/docs/section05.html\#5\_7}{Setting DNS SRV Records}
\end{itemize}


\section{Clustering}
\label{sec:clustering}
\ind{clustering}

\subsection{How it Works}
\label{sec:howitworks}
\ind{clustering!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 \term{\~{}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\ldots

Each \ejabberd{} node has the following modules:
\begin{itemize}
\item router,
\item local router,
\item session manager,
\item s2s manager.
\end{itemize}

\subsubsection{Router}
\ind{clustering!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.

\subsubsection{Local Router}
\ind{clustering!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.

\subsubsection{Session Manager}
\ind{clustering!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.

\subsubsection{s2s Manager}
\ind{clustering!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.

\subsection{Clustering Setup}
\label{sec:cluster}
\ind{clustering!setup}

Suppose you already configured \ejabberd{} on one machine named (\term{first}),
and you need to setup another one to make an \ejabberd{} cluster. Then do
following steps:

\begin{enumerate}
\item Copy \verb|~ejabberd/.erlang.cookie| file from \term{first} to
  \term{second}.

  (alt) You can also add ``\verb|-cookie content_of_.erlang.cookie|''
  option to all ``\shell{erl}'' commands below.

\item On \term{second} run as the `\term{ejabberd}' user in the directory
  where \ejabberd{} will work later the following command:

\begin{verbatim}
erl -sname ejabberd \
    -mnesia extra_db_nodes "['ejabberd@first']" \
    -s mnesia
\end{verbatim}

  This will start Mnesia serving the same database as \node{ejabberd@first}.
  You can check this by running the command ``\verb|mnesia:info().|''. You
  should see a lot of remote tables and a line like the following:

\begin{verbatim}
running db nodes   = [ejabberd@first, ejabberd@second]
\end{verbatim}


\item Now run the following in the same ``\shell{erl}'' session:

\begin{verbatim}
mnesia:change_table_copy_type(schema, node(), disc_copies).
\end{verbatim}

  This will create local disc storage for the database.

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


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

  Which tables to replicate is very dependant on your needs, you can get
  some hints from the command ``\verb|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 \footahref{http://www.erlang.se/doc/doc-5.4.9/lib/mnesia-4.2.2/doc/html/Mnesia\_chap5.html\#5.3}
  {section 5.3 (Table Fragmentation) of Mnesia User's Guide} can be helpful.
  % The above URL needs update every Erlang release!

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


\item Run ``\verb|init:stop().|'' or just ``\verb|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 \term{first}.


\item Now run \ejabberd{} on \term{second} with almost the same config as
  on \term{first} (you probably don't need to duplicate ``\verb|acl|''
  and ``\verb|access|'' options --- they will be taken from
  \term{first}, and \verb|mod_muc| and \verb|mod_irc| should be
  enabled only on one machine in the cluster).
\end{enumerate}

You can repeat these steps for other machines supposed to serve this
domain.

% TODO
% See also the section about ejabberdctl!!!!
%\section{Backup and Restore}
%\label{sec:backup}
%\ind{backup}

\appendix{}
\section{Built-in Modules}
\label{sec:modules}
\ind{modules}

\subsection{Overview}
\label{sec:modoverview}
\ind{modules!overview}\ind{XMPP compliancy}

The following table lists all modules available in the official \ejabberd{}
distribution. You can find more
\footahref{http://ejabberd.jabber.ru/contributions}{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:
\begin{itemize}
\item ``\_ldap'', this means that the module needs an LDAP server as backend.
\item ``\_odbc'', this means that the module needs an ODBC compatible database,
  a MySQL database, or a PostgreSQL database as backend.
\item Nothing, this means that the modules uses Erlang's built-in database
  Mnesia as backend.
\end{itemize}

\begin{table}[H]
  \centering
  \begin{tabular}{|l|l|l|l|}
    \hline Module & Feature & Dependencies & Needed for XMPP? \\ 
    \hline \hline \modadhoc{} & Ad-Hoc Commands (\jepref{0050}) &  & No \\ 
    \hline \modannounce{} & Manage announcements & \modadhoc{} & No \\ 
    \hline \modconfigure{} & Support for online & \modadhoc{} & No \\ 
    & configuration of ejabberd & & \\ 
    \hline \moddisco{} & Service Discovery (\jepref{0030}) &  & No \\ 
    \hline \modecho{} & Echoes Jabber packets &  & No \\ 
    \hline \modirc{} & IRC transport &  & No \\ 
    \hline \modlast{} & Last Activity (\jepref{0012}) &  & No \\ 
    \hline \modlastodbc{} & Last Activity (\jepref{0012}) & ODBC compatible & No \\ 
    & & database, MySQL & \\
    & & or PostgreSQL & \\
    \hline \modmuc{} & Multi-User Chat (\jepref{0045}) &  & No \\ 
    \hline \modmuclog{} & Multi-User Chat room logging & \modmuc{} & No \\ 
    \hline \modoffline{} & Offline message storage &  & No \\ 
    \hline \modofflineodbc{} & Offline message storage & ODBC compatible & No \\ 
    & & database, MySQL & \\
    & & or PostgreSQL & \\
    \hline \modprivacy{} & Blocking Communication &  & Yes \\ 
    \hline \modprivate{} & Private XML Storage (\jepref{0049}) &  & No \\ 
    \hline \modpubsub{} & Publish-Subscribe (\jepref{0060}) &  & No \\ 
    \hline \modregister{} & In-Band Registration (\jepref{0077}) &  & No \\ 
    \hline \modroster{} & Roster management &  & Yes (*) \\ 
    \hline \modrosterodbc{} & Roster management & ODBC compatible & Yes (*) \\ 
    & & database, MySQL & \\
    & & or PostgreSQL & \\
    \hline \modservicelog{} & Copy user messages to logger service &  & No \\ 
    \hline \modsharedroster{} & Shared roster management & \modroster{} or & No \\ 
    & & \modrosterodbc{} & \\ 
    \hline \modstats{} & Statistics Gathering (\jepref{0039}) &  & No \\ 
    \hline \modtime{} & Entity Time (\jepref{0090}) &  & No \\ 
    \hline \modvcard{} & vcard-temp (\jepref{0054}) &  & No \\ 
    \hline \modvcardldap{} & vcard-temp (\jepref{0054}) & LDAP server & No \\ 
    \hline \modvcardodbc{} & vcard-temp (\jepref{0054}) & ODBC compatible & No \\ 
    & & database, MySQL & \\
    & & or PostgreSQL & \\
    \hline \modversion{} & Software Version (\jepref{0092}) &  & No\\
    \hline
  \end{tabular}
\end{table}

(*) This module or a similar one with another database backend is needed for
XMPP compliancy.

\subsection{Common Options}
\label{sec:modcommonopts}

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

\subsubsection{\option{iqdisc}}
\label{sec:modiqdiscoption}
\ind{options!iqdisc}

Many modules define handlers for processing IQ queries of different namespaces
to this server or to a user (e.\,g.\ to \jid{example.org} or to
\jid{user@example.org}). This option defines processing discipline for
these queries. Possible values are:
\begin{description}
\titem{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.
\titem{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.
\titem{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).
\end{description}

Example:
\begin{verbatim}
  {modules,
   [
    ...
    {mod_time, [{iqdisc, no_queue}]},
    ...
   ]}.
\end{verbatim}

\subsubsection{\option{hosts}}
\label{sec:modhostsoption}
\ind{options!hosts}

A module acting as a service can have one or more hostnames. These hostnames
can be defined with the \option{hosts} option.

Examples:
\begin{itemize}
\item Serving the \ind{modules!\modecho{}}echo module on one domain:
  \begin{itemize}
  \item
    \begin{verbatim}
  {modules,
   [
    ...
    {mod_echo, [{hosts, ["echo.example.org"]}]},
    ...
   ]}.
\end{verbatim}
  \item Backwards compatibility with older ejabberd versions can be retained
    with:
    \begin{verbatim}
  {modules,
   [
    ...
    {mod_echo, [{host, "echo.example.org"}]},
    ...
   ]}.
\end{verbatim}
  \end{itemize}
  \item Serving the echo module on two domains:
    \begin{verbatim}
  {modules,
   [
    ...
    {mod_echo, [{hosts, ["echo.example.net", "echo.example.com"]}]},
    ...
   ]}.
\end{verbatim}
\end{itemize}

\subsection{\modannounce{}}
\label{sec:modannounce}
\ind{modules!\modannounce{}}\ind{MOTD}\ind{message of the day}\ind{announcements}

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 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
\jid{example.org}, while the JID between brackets will apply to all virtual
hosts:
\begin{description}
\titem{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 \ind{modules!\modoffline{}}offline storage
  (see section~\ref{sec:modoffline}) is enabled.
\titem{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.
\titem{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
  \term{announce/online}).
\titem{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 \emph{not sent} to any currently connected user.
\titem{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).
\end{description}

Options:
\begin{description}
\titem{access} \ind{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).
\end{description}

Examples:
\begin{itemize}
\item Only administrators can send announcements:
  \begin{verbatim}
  {access, announce, [{allow, admins}]}.

  {modules,
   [
    ...
    {mod_announce, [{access, announce}]},
    ...
   ]}.
\end{verbatim}
\item Administrators as well as the direction can send announcements:
  \begin{verbatim}
  {acl, direction, {user, "big_boss", "example.org"}}.
  {acl, direction, {user, "assistant", "example.org"}}.
  {acl, admins, {user, "admin", "example.org"}}.
  ...
  {access, announce, [{allow, admins},
                      {allow, direction}]}.
  ...
  {modules,
   [
    ...
    {mod_announce, [{access, announce}]},
    ...
   ]}.
\end{verbatim}
\end{itemize}

\subsection{\moddisco{}}
\label{sec:moddisco}
\ind{modules!\moddisco{}}\ind{protocols!JEP-0030: Service Discovery}\ind{protocols!JEP-0011: Jabber Browsing}\ind{protocols!JEP-0094: Agent Information}

This module adds support for Service Discovery (\jepref{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 (\jepref{0011}) and Agent Information
(\jepref{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:
\begin{description}
\iqdiscitem{Service Discovery (\ns{http://jabber.org/protocol/disco\#items} and
  \ns{http://jabber.org/protocol/disco\#info})}
\titem{extra\_domains} \ind{options!extra\_domains}With this option,
  extra domains can be added to the Service Discovery item list.
\end{description}

Examples:
\begin{itemize}
\item To serve a link to the Jabber User Directory on \jid{jabber.org}:
  \begin{verbatim}
  {modules,
   [
    ...
    {mod_disco, [{extra_domains, ["users.jabber.org"]}]},
    ...
   ]}.
\end{verbatim}
\item To serve a link to the transports on another server:
  \begin{verbatim}
  {modules,
   [
    ...
    {mod_disco, [{extra_domains, ["icq.example.com",
                                  "msn.example.com"]}]},
    ...
   ]}.
\end{verbatim}
\item To serve a link to a few friendly servers:
  \begin{verbatim}
  {modules,
   [
    ...
    {mod_disco, [{extra_domains, ["example.org",
                                  "example.com"]}]},
    ...
   ]}.
\end{verbatim}
\end{itemize}


\subsection{\modecho{}}
\label{sec:modecho}
\ind{modules!\modecho{}}\ind{debugging}

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

Options:
\begin{description}
\hostitem{echo}
\end{description}

Examples:
\begin{itemize}
\item Mirror, mirror, on the wall, who is the most beautiful
  of them all?
  \begin{verbatim}
  {modules,
   [
    ...
    {mod_echo, [{hosts, ["mirror.example.org"]}]},
    ...
   ]}.
\end{verbatim}
\item If you still do not understand the inner workings of \modecho{},
  you can find a few more examples in section~\ref{sec:modhostsoption}.
\end{itemize}

\subsection{\modirc{}}
\label{sec:modirc}
\ind{modules!\modirc{}}\ind{IRC}

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

End user information:
\ind{protocols!groupchat 1.0}\ind{protocols!JEP-0045: Multi-User Chat}
\begin{itemize}
\item A \Jabber{} client with ``groupchat 1.0'' support or Multi-User
  Chat support (\jepref{0045}) is necessary to join IRC channels.
\item An IRC channel can be joined in nearly the same way as joining a
  \Jabber{} Multi-User Chat room. The difference is that the room name will
  be ``channel\%\jid{irc.example.org}'' in case \jid{irc.example.org} is
  the IRC server hosting ``channel''. And of course the host should point
  to the IRC transport instead of the Multi-User Chat service.
\item You can register your nickame by sending ``IDENTIFY password'' to \\
  \jid{nickserver!irc.example.org@irc.jabberserver.org}.
\item Entering your password is possible by sending ``LOGIN nick password'' \\
  to \jid{nickserver!irc.example.org@irc.jabberserver.org}.
\item When using a popular \Jabber{} server, it can occur that no
  connection can be achieved with some IRC servers because they limit the
  number of conections from one IP.
\end{itemize}

Options:
\begin{description}
\hostitem{irc}
\titem{access} \ind{options!access}This option can be used to specify who
  may use the IRC transport (default value: \term{all}).
\end{description}

Examples:
\begin{itemize}
\item In the first example, the IRC transport is available on (all) your
  virtual host(s) with the prefix ``\jid{irc.}''. Furthermore, anyone is
  able to use the transport.
  \begin{verbatim}
  {modules,
   [
    ...
    {mod_irc, [{access, all}]},
    ...
   ]}.
\end{verbatim}
% bug in current svn!!: irc-transport.example.com will *not* show up in the service discovery items; instead you will see irc.example.com!!!!
\item In next example the IRC transport is available on the two virtual hosts
  \jid{example.net} and \jid{example.com} with different prefixes on each host.
  Moreover, the transport is only accessible by paying customers registered on
  our domains and on other servers.
  \begin{verbatim}
  {acl, paying_customers, {user, "customer1", "example.net"}}.
  {acl, paying_customers, {user, "customer2", "example.com"}}.
  {acl, paying_customers, {user, "customer3", "example.org"}}.
  ...
  {access, paying_customers, [{allow, paying_customers},
                              {deny, all}]}.
  ...
  {modules,
   [
    ...
    {mod_irc, [{access, paying_customers},
               {hosts, ["irc.example.net", "irc-transport.example.com"]}]},
    ...
   ]}.
\end{verbatim}
\end{itemize}

\subsection{\modlast{}}
\label{sec:modlast}
\ind{modules!\modlast{}}\ind{protocols!JEP-0012: Last Activity}

This module adds support for Last Activity (\jepref{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:
\begin{description}
\iqdiscitem{Last activity (\ns{jabber:iq:last})}
\end{description}

\subsection{\modmuc{}}
\label{sec:modmuc}
\ind{modules!\modmuc{}}\ind{protocols!JEP-0045: Multi-User Chat}\ind{conferencing}

With this module enabled, your server will support Multi-User Chat
(\jepref{0045}). End users will be able to join text conferences. Notice
that this module is not (yet) clusterable.


Some of the features of Multi-User Chat:
\begin{itemize}
\item Sending private messages to room participants.
\item Inviting users.
\item Setting a conference topic.
\item Creating password protected rooms.
\item Kicking and banning participants.
\end{itemize}

Options:
\begin{description}
\hostitem{conference}
\titem{access} \ind{options!access}You can specify who is allowed to use
  the Multi-User Chat service (by default, everyone is allowed to use it).
\titem{access\_create} \ind{options!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).
\titem{access\_admin} \ind{options!access\_admin}This option specifies
  who is allowed to administrate the Multi-User Chat service (the default
  value is \term{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.
\end{description}

Examples:
\begin{itemize}
\item In the first example everyone is allowed to use the Multi-User Chat
  service. Everyone will also be able to create new rooms but only the user
  \jid{admin@example.org} is allowed to administrate any room. In this
  example he is also a global administrator. When \jid{admin@example.org}
  sends a message such as ``Tomorrow, the \Jabber{} server will be moved
  to new hardware. This will involve service breakdowns around 23:00 UMT.
  We apologise for this inconvenience.'' to \jid{conference.example.org},
  it will be displayed in all active rooms.
  \begin{verbatim}
  {acl, admins, {user, "admin", "example.org"}}.
  ...
  {access, muc_admins, [{allow, admins}]}.
  ...
  {modules,
   [
    ...
    {mod_muc, [{access, all},
               {access_create, all},
               {access_admin, muc_admins}]},
    ...
   ]}.
\end{verbatim}
\item In the second example the Multi-User Chat service is only accessible by
  paying customers registered on our domains and on other servers. Of course
  the administrator is also allowed to access rooms. In addition, he is the
  only authority able to create and administer rooms. When
  \jid{admin@example.org} sends a message such as ``Tomorrow, the \Jabber{}
  server will be moved to new hardware. This will involve service breakdowns
  around 23:00 UMT. We apologise for this inconvenience.'' to
  \jid{conference.example.org}, it will be displayed in all active rooms.
  \begin{verbatim}
  {acl, paying_customers, {user, "customer1", "example.net"}}.
  {acl, paying_customers, {user, "customer2", "example.com"}}.
  {acl, paying_customers, {user, "customer3", "example.org"}}.
  {acl, admins, {user, "admin", "example.org"}}.
  ...
  {access, muc_admins, [{allow, admins},
                        {deny, all}]}.
  {access, muc_access, [{allow, paying_customers},
                        {allow, admins},
                        {deny, all}]}.
  ...
  {modules,
   [
    ...
    {mod_muc, [{access, muc_access},
               {access_create, muc_admins},
               {access_admin, muc_admins}]},
    ...
   ]}.
\end{verbatim}
\end{itemize}

\subsection{\modmuclog{}}
\label{sec:modmuclog}
\ind{modules!\modmuclog{}}

This module enables optional logging of Multi-User Chat conversations to HTML.
Once you enable this module, join a chatroom with enought privileges using a MUC capable Jabber client,
request the configuration form and there you will have an option to enable chatroom logging.

Some of the features of generated logs:
\begin{itemize}
\item A lot of information about chatroom is added on top of the page: Room title, JID, subject author, subject and configuration.
\item Room title and JID are links to join the chatroom (using XMPP-IRI).
\item Subject and chatroom configuration changes are tracked and displayed.
\item Joins, leaves, nick changes, kicks, bans and /me are tracked and displayed, including the reason when available.
\item Generated HTML files are XHTML 1.0 Transitional and CSS compliant.
\item Timestamps are self-referencing links.
\item Links on top for quicker navigation: Previous day, Next day, Up.
\item CSS is used for style definition, and a custom CSS file can be used.
\item URLs on messages and subjects are converted to hyperlinks.
\item Timezone used on timestamps is shown on the log files.
\item A custom link can be added on top of page.
\end{itemize}

Options:
\begin{description}
\titem{access\_log}\ind{options!access\_log}
    Restricts which users are allowed to enable or disable chatroom logging using ACL and ACCESS.
    Default: \term{muc\_admin}.
    If you want to allow any chatroom owner put: \term{muc}.
\titem{cssfile}\ind{options!cssfile}
    If HTMLs will use a custom CSS file or the embedded one.
    Allowed values:
        \term{false}: HTMLs will include the standard CSS code;
        \term{"CSS-URL"}: the URL of the CSS file (for example: "http://example.com/my.css").
    Default: \term{false}.
\titem{dirtype}\ind{options!dirtype}
    Type of directory that will be created.
	Allowed values: 
		\term{subdirs}: creates subdirectories for year and month; 
        \term{plain}: the filename contains the full date, no subdirs.
    Default: \term{subdirs}.
\titem{outdir}\ind{options!outdir}
    Full path to the directory where html will be generated.
    Make sure the system user has write access on that directory. 
    Default: \term{"www/muc"}.
\titem{timezone}\ind{options!timezone}
    What timezone should be used.
    Allowed values:
		\term{local}: use local time, as reported to Erlang by the operating system;
        \term{universal}: use GMT/UTC time.
    Default: \term{local}.
\titem{top\_link}\ind{options!top\_link}
    Customizable link on top right corner. Syntax of this option: \term{\{"URL", "Text"\}}.
    Default: \term{\{"/", "Home"\}}.
\end{description}

Example configuration:
\begin{verbatim}
  {modules,
   [
    ...
    {mod_muc_log, [
               {access_log, muc},
               {cssfile, "http://example.com/my.css"},
               {dirtype, plain},
               {outdir, "/var/www/muclogs"},
               {timezone, universal},
               {top_link, {"http://www.jabber.ru", "Jabber.ru"}}
    ]},
    ...
   ]}.
\end{verbatim}

\subsection{\modoffline{}}
\label{sec:modoffline}
\ind{modules!\modoffline{}}

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
\term{ejabberdctl}\ind{ejabberdctl} has a command to delete expired messages
(see section~\ref{sec:ejabberdctl}).

\subsection{\modprivacy{}}
\label{sec:modprivacy}
\ind{modules!\modprivacy{}}\ind{Blocking Communication}\ind{Privacy Rules}\ind{protocols!RFC 3921: XMPP IM}

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:
\begin{quote}
\begin{itemize}
\item Retrieving one's privacy lists. 
\item Adding, removing, and editing one's privacy lists. 
\item Setting, changing, or declining active lists. 
\item Setting, changing, or declining the default list (i.e., the list that
  is active by default). 
\item Allowing or blocking messages based on JID, group, or subscription type
  (or globally). 
\item Allowing or blocking inbound presence notifications based on JID, group,
  or subscription type (or globally). 
\item Allowing or blocking outbound presence notifications based on JID, group,
  or subscription type (or globally). 
\item Allowing or blocking IQ stanzas based on JID, group, or subscription type
  (or globally). 
\item Allowing or blocking all communications based on JID, group, or
  subscription type (or globally).
\end{itemize}
(from \ahrefurl{http://www.xmpp.org/specs/rfc3921.html\#privacy})
\end{quote}

Options:
\begin{description}
\iqdiscitem{Blocking Communication (\ns{jabber:iq:privacy})}
\end{description}

\subsection{\modprivate{}}
\label{sec:modprivate}
\ind{modules!\modprivate{}}\ind{protocols!JEP-0049: Private XML Storage}\ind{protocols!JEP-0048: Bookmark Storage}

This module adds support for Private XML Storage (\jepref{0049}):
\begin{quote}
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 (\jepref{0048}).
\end{quote}

Options:
\begin{description}
\iqdiscitem{Private XML Storage (\ns{jabber:iq:private})}
\end{description}

\subsection{\modpubsub{}}
\label{sec:modpubsub}
\ind{modules!\modpubsub{}}\ind{protocols!JEP-0060: Publish-Subscribe}

This module offers a Publish-Subscribe Service (\jepref{0060}).
Publish-Subscribe can be used to develop (examples are taken from the JEP):
\begin{quote}
\begin{itemize}
\item news feeds and content syndacation,
\item avatar management,
\item shared bookmarks,
\item auction and trading systems,
\item online catalogs,
\item workflow systems,
\item network management systems,
\item NNTP gateways,
\item vCard/profile management,
\item and weblogs.
\end{itemize}
\end{quote} 

\ind{J-EAI}\ind{EAI}\ind{ESB}\ind{Enterprise Application Integration}\ind{Enterprise Service Bus}
Another example is \footahref{http://www.process-one.net/en/projects/j-eai/}{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 \modpubsub{}.

Options:
\begin{description}
\hostitem{pubsub}
\titem{served\_hosts} \ind{options!served\_hosts}To specify which hosts needs to
  be served, you can use this option. If absent, only the main \ejabberd{}
  host is served. % Not a straigtforward description! This needs to be improved!
\titem{access\_createnode} \ind{options!access\_createnode}
    Restricts which users are allowed to create pubsub nodes using ACL and ACCESS.
    Default: \term{pubsub\_createnode}.
\end{description}

Example:
\begin{verbatim}
  {modules,
   [
    ...
    {mod_pubsub, [{served_hosts, ["example.com",
                                  "example.org"]},
                  {access_createnode, pubsub_createnode}]}
    ...
   ]}.
\end{verbatim}

\subsection{\modregister{}}
\label{sec:modregister}
\ind{modules!\modregister{}}\ind{protocols!JEP-0077: In-Band Registration}\ind{public registration}

This module adds support for In-Band Registration (\jepref{0077}). This protocol
enables end users to use a \Jabber{} client to:
\begin{itemize}
\item Register a new account on the server.
\item Change the password from an existing account on the server.
\item Delete an existing account on the server.
\end{itemize}


Options:
\begin{description}
\titem{access} \ind{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 dennied. (there are no
  restrictions by default).
\iqdiscitem{In-Band Registration (\ns{jabber:iq:register})}
\end{description}

Examples:
\begin{itemize}
\item Next example prohibits the registration of too short account names and of
  account names with exotic characters in it:
  \begin{verbatim}
  {acl, shortname, {user_glob, "?"}}.
  {acl, shortname, {user_glob, "??"}}.
  {acl, strangename, {user_regexp, "^..?$"}}.
  ...
  {access, register, [{deny, shortname},
                      {deny, strangename},
                      {allow, all}]}.
  ...
  {modules,
   [
    ...
    {mod_register, [{access, register}]},
    ...
   ]}.
\end{verbatim}
\item The in-band registration of new accounts can be prohibited by changing the
  \option{access} option. If you really want to disable all In-Band Registration
  functionality, that is changing passwords in-band and deleting accounts
  in-band, you have to remove \modregister{} from the modules list. In this
  example all In-Band Registration functionality is disabled:
  \begin{verbatim}
  {access, register, [{deny, all}]}.

  {modules,
   [
    ...
%    {mod_register, [{access, register}]},
    ...
   ]}.
\end{verbatim}
\end{itemize}

\subsection{\modroster{}}
\label{sec:modroster}
\ind{modules!\modroster{}}\ind{roster management}\ind{protocols!RFC 3921: XMPP IM}

This module implements roster management as defined in \footahref{http://www.xmpp.org/specs/rfc3921.html\#roster}{RFC 3921: XMPP IM}.

Options:
\begin{description}
\iqdiscitem{Roster Management (\ns{jabber:iq:roster})}
\end{description}

\subsection{\modservicelog{}}
\label{sec:modservicelog}
\ind{modules!\modservicelog{}}\ind{message auditing}\ind{Bandersnatch}

This module adds support for logging end user packets via a \Jabber{} message
auditing service such as
\footahref{http://www.funkypenguin.co.za/bandersnatch/}{Bandersnatch}. All user
packets are encapsulated in a \verb|<route/>| element and sent to the specified
service(s).

Options:
\begin{description}
\titem{loggers} \ind{options!loggers}With this option a (list of) service(s)
  that will receive the packets can be specified.
\end{description}

Examples:
\begin{itemize}
\item To log all end user packets to the Bandersnatch service running on
  \jid{bandersnatch.example.com}:
  \begin{verbatim}
  {modules,
   [
    ...
    {mod_service_log, [{loggers, ["bandersnatch.example.com"]}]},
    ...
   ]}.
\end{verbatim}
\item To log all end user packets to the Bandersnatch service running on
  \jid{bandersnatch.example.com} and the backup service on 
  \jid{bandersnatch.example.org}:
  \begin{verbatim}
  {modules,
   [
    ...
    {mod_service_log, [{loggers, ["bandersnatch.example.com",
                                  "bandersnatch.example.org"]}]},
    ...
   ]}.
\end{verbatim}
\end{itemize}

\subsection{\modsharedroster{}}
\label{sec:modsharedroster}
\ind{modules!\modsharedroster{}}\ind{shared roster groups}

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 \emph{only} via the web interface. Each group
has a unique identification and the following parameters:
\begin{description}
\item[Name] The name of the group, which will be displayed in the roster.
\item[Description] The description of the group. This parameter doesn't affect
  anything.
\item[Members] A list of full JIDs of group members, entered one per line in
  the web interface.
\item[Displayed groups] A list of groups that will be in the rosters of this
  group's members.
\end{description}

Examples:
\begin{itemize}
\item Take the case of a computer club that wants all its members seeing each
  other in their rosters. To achieve this, they need to create a shared roster
  group similar to next table:
\begin{table}[H]
  \centering
  \begin{tabular}{|l|l|}
    \hline Identification& Group `\texttt{club\_members}'\\
    \hline Name& Club Members\\
    \hline Description& Members from the computer club\\
    \hline Members&
    {\begin{tabular}{l}
        \jid{member1@example.org}\\
        \jid{member2@example.org}\\
        \jid{member3@example.org}
      \end{tabular}
    }\\
    \hline Displayed groups& \texttt{club\_members}\\
    \hline
  \end{tabular}
\end{table}
\item In another case we have a company which has three divisions: Management,
  Marketing and Sales. All group members should see all other members in their
  rosters. Additonally, all managers should have all marketing and sales people
  in their roster. Simultaneously, all marketeers and the whole sales team
  should see all managers. This scenario can be achieved by creating shared
  roster groups as shown in the following table:
\begin{table}[H]
  \centering
  \begin{tabular}{|l|l|l|l|}
    \hline Identification&
    Group `\texttt{management}'&
    Group `\texttt{marketing}'&
    Group `\texttt{sales}'\\
    \hline Name& Management& Marketing& Sales\\
    \hline Description& \\
    Members&
    {\begin{tabular}{l}
        \jid{manager1@example.org}\\
        \jid{manager2@example.org}\\
        \jid{manager3@example.org}\\
        \jid{manager4@example.org}
      \end{tabular}
    }&
    {\begin{tabular}{l}
        \jid{marketeer1@example.org}\\
        \jid{marketeer2@example.org}\\
        \jid{marketeer3@example.org}\\
        \jid{marketeer4@example.org}
      \end{tabular}
    }&
    {\begin{tabular}{l}
        \jid{saleswoman1@example.org}\\
        \jid{salesman1@example.org}\\
        \jid{saleswoman2@example.org}\\
        \jid{salesman2@example.org}
      \end{tabular}
    }\\
    \hline Displayed groups&
    {\begin{tabular}{l}
        \texttt{management}\\
        \texttt{marketing}\\
        \texttt{sales}
      \end{tabular}
    }&
    {\begin{tabular}{l}
        \texttt{management}\\
        \texttt{marketing}
      \end{tabular}
    }&
    {\begin{tabular}{l}
        \texttt{management}\\
        \texttt{sales}
      \end{tabular}
    }\\
    \hline
  \end{tabular}
\end{table}
\end{itemize}

\subsection{\modstats{}}
\label{sec:modstats}
\ind{modules!\modstats{}}\ind{protocols!JEP-0039: Statistics Gathering}\ind{statistics}

This module adds support for Statistics Gathering (\jepref{0039}). This protocol
allows you to retrieve next statistics from your \ejabberd{} deployment:
\begin{itemize}
\item Total number of registered users on the current virtual host (users/total).
\item Total number of registered users on all virtual hosts (users/all-hosts/total).
\item Total number of online users on the current virtual host (users/online).
\item Total number of online users on all virtual hosts (users/all-hosts/online).
\end{itemize}

Options:
\begin{description}
\iqdiscitem{Statistics Gathering (\ns{http://jabber.org/protocol/stats})}
\end{description}

As there are only a small amount of clients (for \ind{Tkabber}example
\footahref{http://tkabber.jabber.ru/}{Tkabber}) and software libraries with
support for this JEP, a few examples are given of the XML you need to send
in order to get the statistics. Here they are:
\begin{itemize}
\item You can request the number of online users on the current virtual host
  (\jid{example.org}) by sending:
  \begin{verbatim}
<iq to='example.org' type='get'>
  <query xmlns='http://jabber.org/protocol/stats'>
    <stat name='users/online'/>
  </query>
</iq>
\end{verbatim}
\item You can request the total number of registered users on all virtual hosts
  by sending:
  \begin{verbatim}
<iq to='example.org' type='get'>
  <query xmlns='http://jabber.org/protocol/stats'>
    <stat name='users/all-hosts/total'/>
  </query>
</iq>
\end{verbatim}
\end{itemize}

\subsection{\modtime{}}
\label{sec:modtime}
\ind{modules!\modtime{}}\ind{protocols!JEP-0090: Entity Time}

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

Options:
\begin{description}
\iqdiscitem{Entity Time (\ns{jabber:iq:time})}
\end{description}

\subsection{\modvcard{}}
\label{sec:modvcard}
\ind{modules!\modvcard{}}\ind{JUD}\ind{Jabber User Directory}\ind{vCard}\ind{protocols!JEP-0054: vcard-temp}

This module allows end users to store and retrieve their vCard, and to retrieve
other users vCards, as defined in vcard-temp (\jepref{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:
\begin{description}
\hostitem{vjud}
\iqdiscitem{\ns{vcard-temp}}
\titem{search} \ind{options!search}This option specifies whether the search
  functionality is enabled (value: \term{true}) or disabled
  (value: \term{false}). If disabled, the option \term{hosts} will be
  ignored and the \Jabber{} User Directory service will not appear in the
  Service Discovery item list. The default value is \term{true}.
\titem{matches} \ind{options!matches}With this option, the number of reported
  search results can be limited. If the option's value is set to \term{infinity},
  all search results are reported. The default value is \term{30}.
\titem{allow\_return\_all} \ind{options!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
  \term{false}.
\titem{search\_all\_hosts} \ind{options!search\_all\_hosts}If this option is
  set to \term{true}, search operations will apply to all virtual hosts.
  Otherwise only the current host will be searched. The default value is
  \term{true}.
\end{description}

Examples:
\begin{itemize}
\item In this first situation, search results are limited to twenty items,
  every user who added information to their vCard will be listed when people
  do an empty search, and only users from the current host will be returned:
  \begin{verbatim}
  {modules,
   [
    ...
    {mod_vcard, [{search, true},
                 {matches, 20},
                 {allow_return_all, true},
                 {search_all_hosts, false}]},
    ...
   ]}.
\end{verbatim}
\item The second situation differs in a way that search results are not limited,
  and that all virtual hosts will be searched instead of only the current one:
  \begin{verbatim}
  {modules,
   [
    ...
    {mod_vcard, [{search, true},
                 {matches, infinity},
                 {allow_return_all, true}]},
    ...
   ]}.
\end{verbatim}
\end{itemize}

\subsection{\modversion{}}
\label{sec:modversion}
\ind{modules!\modversion{}}\ind{protocols!JEP-0092: Software Version}

This module implements Software Version (\jepref{0092}). Consequently, it
answers \ejabberd{}'s version when queried.

Options:
\begin{description}
\iqdiscitem{Software Version (\ns{jabber:iq:version})}
\end{description}


\section{Internationalization and Localization}
\label{sec:i18nl10n}
\ind{xml:lang}\ind{internationalization}\ind{localization}\ind{i18n}\ind{l10n}

All built-in modules support the \texttt{xml:lang} attribute inside IQ queries.
Figure~\ref{fig:discorus}, for example, shows the reply to the following query:
\begin{verbatim}
  <iq id='5'
      to='example.org'
      type='get'
      xml:lang='ru'>
    <query xmlns='http://jabber.org/protocol/disco#items'/>
  </iq>
\end{verbatim}

\begin{figure}[htbp]
  \centering
  \insimg{discorus.png}
  \caption{Service Discovery when \texttt{xml:lang='ru'}}
  \label{fig:discorus}
\end{figure}

The web interface also supports the \verb|Accept-Language| HTTP header (compare
figure~\ref{fig:webadmmainru} with figure~\ref{fig:webadmmain})

\begin{figure}[htbp]
  \centering
  \insimg{webadmmainru.png}
  \caption{Top page from the web interface with HTTP header
    ``Accept-Language: ru''}
  \label{fig:webadmmainru}
\end{figure}

\newpage
\section{Release Notes}
\label{sec:releasenotes}
\ind{release notes}

\subsection{ejabberd 0.9}
\verbatiminput{release_notes_0.9.txt}

\subsection{ejabberd 0.9.1}
\verbatiminput{release_notes_0.9.1.txt}

\subsection{ejabberd 0.9.8}
\verbatiminput{release_notes_0.9.8.txt}

\subsection{ejabberd 1.0.0}
\verbatiminput{release_notes_1.0.0.txt}

\subsection{ejabberd 1.1.0}
\verbatiminput{release_notes_1.1.0.txt}

\subsection{ejabberd 1.1.1}
\verbatiminput{release_notes_1.1.1.txt}

\section{Acknowledgements}
\label{sec:acknowledgements}
\ind{acknowledgements}
Thanks to all people who contributed to this guide:
\begin{itemize}
\item Alexey Shchepin (\ahrefurl{xmpp:aleksey@jabber.ru})
\item Florian Zumbiehl (\ahrefurl{xmpp:florz@florz.de})
\item Michael Grigutsch (\ahrefurl{xmpp:migri@jabber.i-pobox.net})
\item Mickael Remond (\ahrefurl{xmpp:mremond@erlang-projects.org})
\item Sander Devrieze (\ahrefurl{xmpp:sander@devrieze.dyndns.org})
\item Sergei Golovan (\ahrefurl{xmpp:sgolovan@nes.ru})
\item Vsevolod Pelipas (\ahrefurl{xmpp:vsevoload@jabber.ru})
\end{itemize}

% TODO
%\section{Glossary}
%\label{sec:glossary}
%\ind{glossary}

%\begin{description}
%\titem{c2s} 
%\titem{s2s}
%\titem{STARTTLS}
%\titem{JEP} (\Jabber{} Enhancement Proposal)
%\titem{Resource}
%\titem{Roster}
%\titem{Transport}
%\titem{JID} (\Jabber{} ID) <Wikipedia>
%\titem{JUD} (\Jabber{} User Directory)
%\titem{vCard} <Wikipedia>
%\titem{Publish-Subscribe}
%\titem{Namespace}
%\titem{Erlang} <Wikipedia>
%\titem{Fault-tolerant}
%\titem{Distributed} <Wikipedia>
%\titem{Node} <Wikipedia>
%\titem{Tuple} <Wikipedia>
%\titem{Regular Expression}
%\titem{ACL} (Access Control List) <Wikipedia>
%\titem{IPv6} <Wikipedia>
%\titem{XDB} ???
%\titem{LDAP} (Lightweight Directory Access Protocol) <Wikipedia>
%\titem{ODBC} (Open Database Connectivity) <Wikipedia>
%\titem{Virtual Hosting} <Wikipedia>
%\titem{}
%\titem{}

%\end{description}



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