path: root/en_US.ISO8859-1/books/handbook/network-servers/chapter.xml

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<!--
     The FreeBSD Documentation Project

     $FreeBSD$
-->
<chapter xmlns="http://docbook.org/ns/docbook"
  xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0"
  xml:id="network-servers">
  <!--
  <chapterinfo>
    <authorgroup>
      <author>
	<firstname>Murray</firstname>
	<surname>Stokely</surname>
	<contrib>Reorganized by in July 2004</contrib>
      </author>
    </authorgroup>
  </chapterinfo>
  -->

  <title>Network Servers</title>

  <sect1 xml:id="network-servers-synopsis">
    <title>Synopsis</title>

    <para>This chapter covers some of the more frequently used network
      services on &unix; systems.  This includes installing,
      configuring, testing, and maintaining many different types of
      network services.  Example configuration files are included
      throughout this chapter for reference.</para>

    <para>By the end of this chapter, readers will know:</para>

    <itemizedlist>
      <listitem>
	<para>How to manage the <application>inetd</application>
	  daemon.</para>
      </listitem>

      <listitem>
	<para>How to set up the Network File System
	  (<acronym>NFS</acronym>).</para>
      </listitem>

      <listitem>
	<para>How to set up the Network Information Server
	  (<acronym>NIS</acronym>) for centralizing and sharing
	  user accounts.</para>
      </listitem>

      <listitem>
	<para>How to set &os; up to act as an <acronym>LDAP</acronym>
	  server or client</para>
      </listitem>

      <listitem>
	<para>How to set up automatic network settings using
	  <acronym>DHCP</acronym>.</para>
      </listitem>

      <listitem>
	<para>How to set up a Domain Name Server
	  (<acronym>DNS</acronym>).</para>
      </listitem>

      <listitem>
	<para>How to set up the <application>Apache</application>
	  <acronym>HTTP</acronym> Server.</para>
      </listitem>

      <listitem>
	<para>How to set up a File Transfer Protocol
	  (<acronym>FTP</acronym>) server.</para>
      </listitem>

      <listitem>
	<para>How to set up a file and print server for &windows;
	  clients using <application>Samba</application>.</para>
      </listitem>

      <listitem>
	<para>How to synchronize the time and date, and set up a
	  time server using the Network Time Protocol
	  (<acronym>NTP</acronym>).</para>
      </listitem>

      <listitem>
	<para>How to set up <acronym>iSCSI</acronym>.</para>
      </listitem>
    </itemizedlist>

    <para>This chapter assumes a basic knowledge of:</para>

    <itemizedlist>
      <listitem>
	<para><filename>/etc/rc</filename> scripts.</para>
      </listitem>

      <listitem>
	<para>Network terminology.</para>
      </listitem>

      <listitem>
	<para>Installation of additional third-party
	  software (<xref linkend="ports"/>).</para>
      </listitem>
    </itemizedlist>
  </sect1>

  <sect1 xml:id="network-inetd">
    <title>The <application>inetd</application>
      Super-Server</title>

    <!--
    <sect1info>
      <authorgroup>
	<author>
	  <firstname>Chern</firstname>
	  <surname>Lee</surname>
	  <contrib>Contributed by </contrib>
	</author>
      </authorgroup>
      <authorgroup>
	<author>
	  <contrib>Updated by </contrib>
	  <othername>The &os; Documentation Project</othername>
	</author>
      </authorgroup>
    </sect1info>
    -->

    <para>The &man.inetd.8; daemon is sometimes referred to as a
      Super-Server because it manages connections for many services.
      Instead of starting multiple applications, only the
      <application>inetd</application> service needs to be started.
      When a connection is received for a service that is managed by
      <application>inetd</application>, it determines which program
      the connection is destined for, spawns a process for that
      program, and delegates the program a socket.  Using
      <application>inetd</application> for services that are not
      heavily used can reduce system load, when compared to running
      each daemon individually in stand-alone mode.</para>

    <para>Primarily, <application>inetd</application> is used to
      spawn other daemons, but several trivial protocols are handled
      internally, such as <application>chargen</application>,
      <application>auth</application>,
      <application>time</application>,
      <application>echo</application>,
      <application>discard</application>, and
      <application>daytime</application>.</para>

    <para>This section covers the basics of configuring
      <application>inetd</application>.</para>

    <sect2 xml:id="network-inetd-conf">
      <title>Configuration File</title>

      <para>Configuration of <application>inetd</application> is
	done by editing <filename>/etc/inetd.conf</filename>.  Each
	line of this configuration file represents an application
	which can be started by <application>inetd</application>.  By
	default, every line starts with a comment
	(<literal>#</literal>), meaning that
	<application>inetd</application> is not listening for any
	applications.  To configure <application>inetd</application>
	to listen for an application's connections, remove the
	<literal>#</literal> at the beginning of the line for that
	application.</para>

      <para>After saving your edits, configure
	<application>inetd</application> to start at system boot by
	editing <filename>/etc/rc.conf</filename>:</para>

      <programlisting>inetd_enable="YES"</programlisting>

      <para>To start  <application>inetd</application> now, so that it
	listens for the service you configured, type:</para>

      <screen>&prompt.root; <userinput>service inetd start</userinput></screen>

      <para>Once <application>inetd</application> is started, it needs
	to be notified whenever a modification is made to
	<filename>/etc/inetd.conf</filename>:</para>

      <example xml:id="network-inetd-reread">
	<title>Reloading the <application>inetd</application>
	  Configuration File</title>

	<screen>&prompt.root; <userinput>service inetd reload</userinput></screen>
      </example>

      <para>Typically, the default entry for an application does not
	need to be edited beyond removing the <literal>#</literal>.
	In some situations, it may be appropriate to edit the default
	entry.</para>

      <para>As an example, this is the default entry for &man.ftpd.8;
	over IPv4:</para>

      <programlisting>ftp     stream  tcp     nowait  root    /usr/libexec/ftpd       ftpd -l</programlisting>

      <para>The seven columns in an entry are as follows:</para>

      <programlisting>service-name
socket-type
protocol
{wait|nowait}[/max-child[/max-connections-per-ip-per-minute[/max-child-per-ip]]]
user[:group][/login-class]
server-program
server-program-arguments</programlisting>

      <para>where:</para>

      <variablelist>
	<varlistentry>
	  <term>service-name</term>

	  <listitem>
	    <para>The service name of the daemon to start.  It must
	      correspond to a service listed in
	      <filename>/etc/services</filename>.  This determines
	      which port <application>inetd</application> listens on
	      for incoming connections to that service.  When using a
	      custom service, it must first be added to
	      <filename>/etc/services</filename>.</para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>socket-type</term>

	  <listitem>
	    <para>Either <literal>stream</literal>,
	      <literal>dgram</literal>, <literal>raw</literal>, or
	      <literal>seqpacket</literal>.  Use
	      <literal>stream</literal> for TCP connections and
	      <literal>dgram</literal> for
	      <acronym>UDP</acronym> services.</para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>protocol</term>

	  <listitem>
	    <para>Use one of the following protocol names:</para>

	    <informaltable frame="none" pgwide="1">
	      <tgroup cols="2">
		<thead>
		  <row>
		    <entry>Protocol Name</entry>
		    <entry>Explanation</entry>
		  </row>
		</thead>

		<tbody>
		  <row>
		    <entry>tcp or tcp4</entry>
		    <entry>TCP IPv4</entry>
		  </row>

		  <row>
		    <entry>udp or udp4</entry>
		    <entry><acronym>UDP</acronym> IPv4</entry>
		  </row>

		  <row>
		    <entry>tcp6</entry>
		    <entry>TCP IPv6</entry>
		  </row>

		  <row>
		    <entry>udp6</entry>
		    <entry><acronym>UDP</acronym> IPv6</entry>
		  </row>

		  <row>
		    <entry>tcp46</entry>
		    <entry>Both TCP IPv4 and IPv6</entry>
		  </row>

		  <row>
		    <entry>udp46</entry>
		    <entry>Both <acronym>UDP</acronym> IPv4 and
		      IPv6</entry>
		  </row>
		</tbody>
	      </tgroup>
	    </informaltable>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>{wait|nowait}[/max-child[/max-connections-per-ip-per-minute[/max-child-per-ip]]]</term>

	  <listitem>
	    <para>In this field, <option>wait</option> or
	      <option>nowait</option> must be specified.
	      <option>max-child</option>,
	      <option>max-connections-per-ip-per-minute</option> and
	      <option>max-child-per-ip</option> are optional.</para>

	    <para><option>wait|nowait</option> indicates whether or
	      not the service is able to handle its own socket.
	      <option>dgram</option> socket types must use
	      <option>wait</option> while
	      <option>stream</option> daemons, which are usually
	      multi-threaded, should use <option>nowait</option>.
	      <option>wait</option> usually hands off multiple sockets
	      to a single daemon, while <option>nowait</option> spawns
	      a child daemon for each new socket.</para>

	    <para>The maximum number of child daemons
	      <application>inetd</application> may spawn is set by
	      <option>max-child</option>.  For example, to limit ten
	      instances of the daemon, place a <literal>/10</literal>
	      after <option>nowait</option>.  Specifying
	      <literal>/0</literal> allows an unlimited number of
	      children.</para>

	    <para><option>max-connections-per-ip-per-minute</option>
	      limits the number of connections from any particular
	      <acronym>IP</acronym> address per minute.  Once the
	      limit  is reached, further connections from this IP
	      address will be dropped until the end of the minute.
	      For example, a value of <literal>/10</literal> would
	      limit any particular <acronym>IP</acronym> address to
	      ten connection attempts per minute.
	      <option>max-child-per-ip</option> limits the number of
	      child processes that can be started on behalf on any
	      single <acronym>IP</acronym> address at any moment.
	      These options can limit excessive resource consumption
	      and help to prevent Denial of Service attacks.</para>

	    <para>An example can be seen in the default settings for
	      &man.fingerd.8;:</para>

	    <programlisting>finger stream  tcp     nowait/3/10 nobody /usr/libexec/fingerd fingerd -k -s</programlisting>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>user</term>

	  <listitem>
	    <para>The username the daemon
	      will run as.  Daemons typically run as
	      <systemitem class="username">root</systemitem>,
	      <systemitem class="username">daemon</systemitem>, or
	      <systemitem class="username">nobody</systemitem>.</para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>server-program</term>

	  <listitem>
	    <para>The full path to the daemon.  If the daemon is a
	      service provided by <application>inetd</application>
	      internally, use <option>internal</option>.</para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>server-program-arguments</term>

	  <listitem>
	    <para>Used to specify any command arguments to be passed
	      to the daemon on invocation.  If the daemon is an
	      internal service, use
	      <option>internal</option>.</para>
	  </listitem>
	</varlistentry>
      </variablelist>
    </sect2>

    <sect2 xml:id="network-inetd-cmdline">
      <title>Command-Line Options</title>

      <para>Like most server daemons, <application>inetd</application>
	has a number of options that can be used to modify its
	behavior.  By default, <application>inetd</application> is
	started with <literal>-wW -C 60</literal>.  These options
	enable TCP wrappers for all services, including internal
	services, and prevent any <acronym>IP</acronym> address from
	requesting any service more than 60 times per minute.</para>

      <para>To change the default options which are passed to
	<application>inetd</application>, add an entry for
	<literal>inetd_flags</literal> in
	<filename>/etc/rc.conf</filename>.  If
	<application>inetd</application> is already running, restart
	it with <command>service inetd restart</command>.</para>

      <para>The available rate limiting options are:</para>

      <variablelist>
	<varlistentry>
	  <term>-c maximum</term>

	  <listitem>
	    <para>Specify the default maximum number of simultaneous
	      invocations of each service, where the default is
	      unlimited.  May be overridden on a per-service basis by
	      using <option>max-child</option> in
	      <filename>/etc/inetd.conf</filename>.</para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>-C rate</term>

	  <listitem>
	    <para>Specify the default maximum number of times a
	      service can be invoked from a single
	      <acronym>IP</acronym> address per minute.  May be
	      overridden on a per-service basis by using
	      <option>max-connections-per-ip-per-minute</option> in
	      <filename>/etc/inetd.conf</filename>.</para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>-R rate</term>

	  <listitem>
	    <para>Specify the maximum number of times a service can be
	      invoked in one minute, where the default is
	      <literal>256</literal>.  A rate of <literal>0</literal>
	      allows an unlimited number.</para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term>-s maximum</term>

	  <listitem>
	    <para>Specify the maximum number of times a service can be
	      invoked from a single <acronym>IP</acronym> address at
	      any one time, where the default is unlimited.  May be
	      overridden on a per-service basis by using
	      <option>max-child-per-ip</option> in
	      <filename>/etc/inetd.conf</filename>.</para>
	  </listitem>
	</varlistentry>
      </variablelist>

      <para>Additional options are available.  Refer to &man.inetd.8;
	for the full list of options.</para>
    </sect2>

    <sect2 xml:id="network-inetd-security">
      <title>Security Considerations</title>

      <para>Many of the daemons which can be managed by
	<application>inetd</application> are not security-conscious.
	Some daemons, such as <application>fingerd</application>, can
	provide information that may be useful to an attacker.  Only
	enable the services which are needed and monitor the system
	for excessive connection attempts.
	<literal>max-connections-per-ip-per-minute</literal>,
	<literal>max-child</literal> and
	<literal>max-child-per-ip</literal> can be used to limit such
	attacks.</para>

      <para>By default, TCP wrappers is enabled.  Consult
	&man.hosts.access.5; for more information on placing TCP
	restrictions on various
	<application>inetd</application> invoked daemons.</para>
    </sect2>
  </sect1>

  <sect1 xml:id="network-nfs">
    <info>
      <title>Network File System (NFS)</title>

      <authorgroup>
	<author>
	  <personname>
	    <firstname>Tom</firstname>
	    <surname>Rhodes</surname>
	  </personname>
	  <contrib>Reorganized and enhanced by </contrib>
	</author>
      </authorgroup>

      <authorgroup>
	<author>
	  <personname>
	    <firstname>Bill</firstname>
	    <surname>Swingle</surname>
	  </personname>
	  <contrib>Written by </contrib>
	</author>
      </authorgroup>
    </info>

    <indexterm><primary>NFS</primary></indexterm>
    <para>&os; supports the Network File System
      (<acronym>NFS</acronym>), which allows a server to share
      directories and files with clients over a network.  With
      <acronym>NFS</acronym>, users and programs can access files on
      remote systems as if they were stored locally.</para>

    <para><acronym>NFS</acronym> has many practical uses.  Some of
      the more common uses include:</para>

    <itemizedlist>
      <listitem>
	<para>Data that would otherwise be duplicated on each client
	  can be kept in a single location and accessed by clients
	  on the network.</para>
      </listitem>

      <listitem>
	<para>Several clients may need access to the
	  <filename>/usr/ports/distfiles</filename> directory.
	  Sharing that directory allows for quick access to the
	  source files without having to download them to each
	  client.</para>
      </listitem>

      <listitem>
	<para>On large networks, it is often more convenient to
	  configure a central <acronym>NFS</acronym> server on which
	  all user home directories are stored.  Users can log into
	  a client anywhere on the network and have access to their
	  home directories.</para>
      </listitem>

      <listitem>
	<para>Administration of <acronym>NFS</acronym> exports is
	  simplified.  For example, there is only one file system
	  where security or backup policies must be set.</para>
      </listitem>

      <listitem>
	<para>Removable media storage devices can be used by other
	  machines on the network.  This reduces the number of devices
	  throughout the network and provides a centralized location
	  to manage their security.  It is often more convenient to
	  install software on multiple machines from a centralized
	  installation media.</para>
      </listitem>
    </itemizedlist>

    <para><acronym>NFS</acronym> consists of a server and one or more
      clients.  The client remotely accesses the data that is stored
      on the server machine.  In order for this to function properly,
      a few processes have to be configured and running.</para>

    <para>These daemons must be running on the server:</para>
    <indexterm>
      <primary>NFS</primary>
	<secondary>server</secondary>
     </indexterm>
     <indexterm>
       <primary>file server</primary>
	<secondary>UNIX clients</secondary>
      </indexterm>

      <indexterm>
	<primary><application>rpcbind</application></primary>
      </indexterm>
      <indexterm>
	<primary><application>mountd</application></primary>
      </indexterm>
      <indexterm>
	<primary><application>nfsd</application></primary>
      </indexterm>

      <informaltable frame="none" pgwide="1">
	<tgroup cols="2">
	  <colspec colwidth="1*"/>
	  <colspec colwidth="3*"/>

	  <thead>
	    <row>
	      <entry>Daemon</entry>
	      <entry>Description</entry>
	    </row>
	  </thead>

	  <tbody>
	    <row>
	      <entry><application>nfsd</application></entry>
	      <entry>The <acronym>NFS</acronym> daemon which services
		requests from <acronym>NFS</acronym> clients.</entry>
	    </row>

	    <row>
	      <entry><application>mountd</application></entry>
	      <entry>The <acronym>NFS</acronym> mount daemon which
		carries out requests received from
		<application>nfsd</application>.</entry>
	    </row>

	    <row>
	      <entry><application>rpcbind</application></entry>
	      <entry> This daemon allows <acronym>NFS</acronym>
		clients to discover which port the
		<acronym>NFS</acronym> server is using.</entry>
	    </row>
	  </tbody>
	</tgroup>
      </informaltable>

      <para>Running &man.nfsiod.8; on the client can improve
	performance, but is not required.</para>

      <sect2 xml:id="network-configuring-nfs">
	<title>Configuring the Server</title>

	<indexterm>
	  <primary>NFS</primary>
	  <secondary>configuration</secondary>
	</indexterm>

      <para>The file systems which the <acronym>NFS</acronym> server
	will share are specified in <filename>/etc/exports</filename>.
	Each line in this file specifies a file system to be exported,
	which clients have access to that file system, and any access
	options.  When adding entries to this file, each exported file
	system, its properties, and allowed hosts must occur on a
	single line.  If no clients are listed in the entry, then any
	client on the network can mount that file system.</para>

      <indexterm>
	<primary>NFS</primary>
	<secondary>export examples</secondary>
      </indexterm>

      <para>The following <filename>/etc/exports</filename> entries
	demonstrate how to export file systems.  The examples can be
	modified to match the file systems and client names on the
	reader's network.  There are many options that can be used in
	this file, but only a few will be mentioned here.  See
	&man.exports.5; for the full list of options.</para>

      <para>This example shows how to export
	<filename>/cdrom</filename> to three hosts named
	<replaceable>alpha</replaceable>,
	<replaceable>bravo</replaceable>, and
	<replaceable>charlie</replaceable>:</para>

      <programlisting>/cdrom -ro <replaceable>alpha</replaceable> <replaceable>bravo</replaceable> <replaceable>charlie</replaceable></programlisting>

      <para>The <literal>-ro</literal> flag makes the file system
	read-only, preventing clients from making any changes to the
	exported file system.  This example assumes that the host
	names are either in <acronym>DNS</acronym> or in
	<filename>/etc/hosts</filename>.  Refer to &man.hosts.5; if
	the network does not have a <acronym>DNS</acronym>
	server.</para>

      <para>The next example exports <filename>/home</filename> to
	three clients by <acronym>IP</acronym> address.  This can be
	useful for networks without <acronym>DNS</acronym> or
	<filename>/etc/hosts</filename> entries.  The
	<literal>-alldirs</literal> flag allows subdirectories to be
	mount points.  In other words, it will not automatically mount
	the subdirectories, but will permit the client to mount the
	directories that are required as needed.</para>

      <programlisting>/usr/home  -alldirs  10.0.0.2 10.0.0.3 10.0.0.4</programlisting>

      <para>This next example exports <filename>/a</filename> so that
	two clients from different domains may access that file
	system.  The <option>-maproot=root</option> allows <systemitem
	  class="username">root</systemitem> on the remote system to
	write data on the exported file system as <systemitem
	  class="username">root</systemitem>.  If
	<literal>-maproot=root</literal> is not specified, the
	client's <systemitem class="username">root</systemitem> user
	will be mapped to the server's <systemitem
	  class="username">nobody</systemitem> account and will be
	subject to the access limitations defined for <systemitem
	  class="username">nobody</systemitem>.</para>

      <programlisting>/a  -maproot=root  host.example.com box.example.org</programlisting>

      <para>A client can only be specified once per file system.  For
	example, if <filename>/usr</filename> is a single file system,
	these entries would be invalid as both entries specify the
	same host:</para>

      <programlisting># Invalid when /usr is one file system
/usr/src   client
/usr/ports client</programlisting>

      <para>The correct format for this situation is to use one
	entry:</para>

      <programlisting>/usr/src /usr/ports  client</programlisting>

      <para>The following is an example of a valid export list, where
	<filename>/usr</filename> and <filename>/exports</filename>
	are local file systems:</para>

      <programlisting># Export src and ports to client01 and client02, but only
# client01 has root privileges on it
/usr/src /usr/ports -maproot=root    client01
/usr/src /usr/ports               client02
# The client machines have root and can mount anywhere
# on /exports. Anyone in the world can mount /exports/obj read-only
/exports -alldirs -maproot=root      client01 client02
/exports/obj -ro</programlisting>

      <para>To enable the processes required by the
	<acronym>NFS</acronym> server at boot time, add these options
	to <filename>/etc/rc.conf</filename>:</para>

      <programlisting>rpcbind_enable="YES"
nfs_server_enable="YES"
mountd_enable="YES"</programlisting>

      <para>The server can be started now by running this
	command:</para>

      <screen>&prompt.root; <userinput>service nfsd start</userinput></screen>

      <para>Whenever the <acronym>NFS</acronym> server is started,
	<application>mountd</application> also starts automatically.
	However, <application>mountd</application> only reads
	<filename>/etc/exports</filename> when it is started.  To make
	subsequent <filename>/etc/exports</filename> edits take effect
	immediately, force <application>mountd</application> to reread
	it:</para>

      <screen>&prompt.root; <userinput>service mountd reload</userinput></screen>
    </sect2>

    <sect2>
      <title>Configuring the Client</title>

      <para>To enable <acronym>NFS</acronym> clients, set this option
	in each client's <filename>/etc/rc.conf</filename>:</para>

      <programlisting>nfs_client_enable="YES"</programlisting>

      <para>Then, run this command on each <acronym>NFS</acronym>
	client:</para>

      <screen>&prompt.root; <userinput>service nfsclient start</userinput></screen>

      <para>The client now has everything it needs to mount a remote
	file system.  In these examples, the server's name is
	<systemitem>server</systemitem> and the client's name is
	<systemitem>client</systemitem>.  To mount
	<filename>/home</filename> on
	<systemitem>server</systemitem> to the
	<filename>/mnt</filename> mount point on
	<systemitem>client</systemitem>:</para>

      <indexterm>
	<primary>NFS</primary>
	<secondary>mounting</secondary>
      </indexterm>
      <screen>&prompt.root; <userinput>mount server:/home /mnt</userinput></screen>

      <para>The files and directories in
	<filename>/home</filename> will now be available on
	<systemitem>client</systemitem>, in the
	<filename>/mnt</filename> directory.</para>

      <para>To mount a remote file system each time the client boots,
	add it to <filename>/etc/fstab</filename>:</para>

      <programlisting>server:/home	/mnt	nfs	rw	0	0</programlisting>

      <para>Refer to &man.fstab.5; for a description of all available
	options.</para>
    </sect2>

    <sect2>
      <title>Locking</title>

      <para>Some applications require file locking to operate
	correctly.  To enable locking, add these lines to
	<filename>/etc/rc.conf</filename> on both the client and
	server:</para>

      <programlisting>rpc_lockd_enable="YES"
rpc_statd_enable="YES"</programlisting>

      <para>Then start the applications:</para>

      <screen>&prompt.root; <userinput>service lockd start</userinput>
&prompt.root; <userinput>service statd start</userinput></screen>

      <para>If locking is not required on the server, the
	<acronym>NFS</acronym> client can be configured to lock
	locally by including <option>-L</option> when running
	<application>mount</application>.  Refer to &man.mount.nfs.8;
	for further details.</para>
    </sect2>

    <sect2 xml:id="network-autofs">
      <title>Automating Mounts with &man.autofs.5;</title>

      <note>
	<para>The &man.autofs.5; automount facility is supported
	  starting with &os;&nbsp;10.1-RELEASE.  To use the
	  automounter functionality in older versions of &os;, use
	  &man.amd.8; instead.  This chapter only describes the
	  &man.autofs.5; automounter.</para>
      </note>


      <indexterm><primary>autofs</primary></indexterm>
      <indexterm>
	<primary>automounter subsystem</primary>
      </indexterm>

      <para>The &man.autofs.5; facility is a common name for several
	components that, together, allow for automatic mounting of
	remote and local filesystems whenever a file or directory
	within that file system is accessed.  It consists of the
	kernel component, &man.autofs.5;, and several userspace
	applications: &man.automount.8;, &man.automountd.8; and
	&man.autounmountd.8;.  It serves as an alternative for
	&man.amd.8; from previous &os; releases.  Amd is still
	provided for backward compatibility purposes, as the two use
	different map format; the one used by autofs is the same as
	with other SVR4 automounters, such as the ones in Solaris,
	MacOS X, and Linux.</para>

      <para>The &man.autofs.5; virtual filesystem is mounted on
	specified mountpoints by &man.automount.8;, usually invoked
	during boot.</para>

      <para>Whenever a process attempts to access file within the
	&man.autofs.5; mountpoint, the kernel will notify
	&man.automountd.8; daemon and pause the triggering process.
	The &man.automountd.8; daemon will handle kernel requests by
	finding the proper map and mounting the filesystem according
	to it, then signal the kernel to release blocked process.  The
	&man.autounmountd.8; daemon automatically unmounts automounted
	filesystems after some time, unless they are still being
	used.</para>

      <para>The primary autofs configuration file is
	<filename>/etc/auto_master</filename>.  It assigns individual
	maps to top-level mounts.  For an explanation of
	<filename>auto_master</filename> and the map syntax, refer to
	&man.auto.master.5;.</para>

      <para>There is a special automounter map mounted on
	<filename>/net</filename>.  When a file is accessed within
	this directory, &man.autofs.5; looks up the corresponding
	remote mount and automatically mounts it.  For instance, an
	attempt to access a file within
	<filename>/net/foobar/usr</filename> would tell
	&man.automountd.8; to mount the <filename
	  >/usr</filename> export from the host
	<systemitem class="fqdomainname">foobar</systemitem>.</para>

      <example>
	<title>Mounting an Export with &man.autofs.5;</title>

	<para>In this example, <command>showmount -e</command> shows
	  the exported file systems that can be mounted from the
	  <acronym>NFS</acronym> server,
	  <systemitem class="fqdomainname">foobar</systemitem>:</para>

	<screen>&prompt.user; <userinput>showmount -e foobar</userinput>
Exports list on foobar:
/usr                               10.10.10.0
/a                                 10.10.10.0
&prompt.user; <userinput>cd /net/foobar/usr</userinput></screen>
      </example>

      <para>The output from <command>showmount</command> shows
	<filename>/usr</filename> as an export.
	When changing directories to <filename
	  >/host/foobar/usr</filename>,
	&man.automountd.8; intercepts the request and attempts to
	resolve the hostname <systemitem
	  class="fqdomainname">foobar</systemitem>.  If successful,
	&man.automountd.8; automatically mounts the source
	export.</para>

      <para>To enable &man.autofs.5; at boot time, add this line to
	<filename>/etc/rc.conf</filename>:</para>

      <programlisting>autofs_enable="YES"</programlisting>

      <para>Then &man.autofs.5; can be started by running:</para>

      <screen>&prompt.root; <userinput>service automount start</userinput>
&prompt.root; <userinput>service automountd start</userinput>
&prompt.root; <userinput>service autounmountd start</userinput></screen>

      <para>The &man.autofs.5; map format is the same as in other
	operating systems.  Information about this format from other
	sources can be useful, like the <link
	  xlink:href="http://web.archive.org/web/20160813071113/http://images.apple.com/business/docs/Autofs.pdf">Mac
	  OS X document</link>.</para>

      <para>Consult the &man.automount.8;, &man.automountd.8;,
	&man.autounmountd.8;, and &man.auto.master.5; manual pages for
	more information.</para>
    </sect2>
  </sect1>

  <sect1 xml:id="network-nis">
    <!--
    <sect1info>
      <authorgroup>
	<author>
	  <firstname>Bill</firstname>
	  <surname>Swingle</surname>
	  <contrib>Written by </contrib>
	</author>
      </authorgroup>
      <authorgroup>
	<author>
	  <firstname>Eric</firstname>
	  <surname>Ogren</surname>
	  <contrib>Enhanced by </contrib>
	</author>
	<author>
	  <firstname>Udo</firstname>
	  <surname>Erdelhoff</surname>
	</author>
      </authorgroup>
    </sect1info>
    -->
    <title>Network Information System
      (<acronym>NIS</acronym>)</title>

    <indexterm><primary>NIS</primary></indexterm>
    <indexterm><primary>Solaris</primary></indexterm>
    <indexterm><primary>HP-UX</primary></indexterm>
    <indexterm><primary>AIX</primary></indexterm>
    <indexterm><primary>Linux</primary></indexterm>
    <indexterm><primary>NetBSD</primary></indexterm>
    <indexterm><primary>OpenBSD</primary></indexterm>
    <indexterm>
      <primary>yellow pages</primary>
      <see>NIS</see>
    </indexterm>

    <para>Network Information System (<acronym>NIS</acronym>) is
      designed to centralize administration of &unix;-like systems
      such as &solaris;, HP-UX, &aix;, Linux, NetBSD, OpenBSD, and
      &os;.  <acronym>NIS</acronym> was originally known as Yellow
      Pages but the name was changed due to trademark issues.   This
      is the reason why <acronym>NIS</acronym> commands begin with
      <literal>yp</literal>.</para>

    <indexterm>
      <primary>NIS</primary>
      <secondary>domains</secondary>
      </indexterm>

    <para><acronym>NIS</acronym> is a Remote Procedure Call
      (<acronym>RPC</acronym>)-based client/server system that allows
      a group of machines within an <acronym>NIS</acronym> domain to
      share a common set of configuration files.  This permits a
      system administrator to set up <acronym>NIS</acronym> client
      systems with only minimal configuration data and to add, remove,
      or modify configuration data from a single location.</para>

    <para>&os; uses version 2 of the <acronym>NIS</acronym>
      protocol.</para>

    <sect2>
      <title><acronym>NIS</acronym> Terms and Processes</title>

      <para>Table 28.1 summarizes the terms and important processes
	used by <acronym>NIS</acronym>:</para>

      <indexterm>
	<primary><application>rpcbind</application></primary>
      </indexterm>
      <indexterm>
	<primary><application>portmap</application></primary>
      </indexterm>

      <table frame="none" pgwide="1">
	<title><acronym>NIS</acronym> Terminology</title>

	<tgroup cols="2">
	  <colspec colwidth="1*"/>
	  <colspec colwidth="3*"/>

	  <thead>
	    <row>
	      <entry>Term</entry>
	      <entry>Description</entry>
	    </row>
	  </thead>

	  <tbody>
	    <row>
	      <entry><acronym>NIS</acronym> domain name</entry>

	      <entry><acronym>NIS</acronym> servers and clients share
		an <acronym>NIS</acronym> domain name.  Typically,
		this name does not have anything to do with
		<acronym>DNS</acronym>.</entry>
	    </row>

	    <row>
	      <entry>&man.rpcbind.8;</entry>

	      <entry>This service enables <acronym>RPC</acronym> and
		must be running in order to run an
		<acronym>NIS</acronym> server or act as an
		<acronym>NIS</acronym> client.</entry>
	    </row>

	    <row>
	      <entry>&man.ypbind.8;</entry>
	      <entry>This service binds an <acronym>NIS</acronym>
		client to its <acronym>NIS</acronym> server.  It will
		take the <acronym>NIS</acronym> domain name and use
		<acronym>RPC</acronym> to connect to the server.  It
		is the core of client/server communication in an
		<acronym>NIS</acronym> environment.  If this service
		is not running on a client machine, it will not be
		able to access the <acronym>NIS</acronym>
		server.</entry>
	    </row>

	    <row>
	      <entry>&man.ypserv.8;</entry>
	      <entry>This is the process for the
		<acronym>NIS</acronym> server.  If this service stops
		running, the server will no longer be able to respond
		to <acronym>NIS</acronym> requests so hopefully, there
		is a slave server to take over.  Some non-&os; clients
		will not try to reconnect using a slave server and the
		<application>ypbind</application> process may need to
		be restarted on these
		clients.</entry>
	    </row>

	    <row>
	      <entry>&man.rpc.yppasswdd.8;</entry>
	      <entry>This process only runs on
		<acronym>NIS</acronym> master servers.  This daemon
		allows <acronym>NIS</acronym> clients to change their
		<acronym>NIS</acronym> passwords.  If this daemon is
		not running, users will have to login to the
		<acronym>NIS</acronym> master server and change their
		passwords there.</entry>
	    </row>
	  </tbody>
	</tgroup>
      </table>
      <!-- XXX Missing: rpc.ypxfrd (not important, though) May only run
      on the master -->
    </sect2>

    <sect2>
      <title>Machine Types</title>

      <indexterm><primary>NIS</primary>
	<secondary>master server</secondary>
      </indexterm>
      <indexterm><primary>NIS</primary>
	<secondary>slave server</secondary>
      </indexterm>
      <indexterm><primary>NIS</primary>
	<secondary>client</secondary>
      </indexterm>

      <para>There are three types of hosts in an
	<acronym>NIS</acronym> environment:</para>

      <itemizedlist>
	<listitem>
	  <para><acronym>NIS</acronym> master server</para>

	  <para>This server acts as a central repository for host
	    configuration information and maintains the
	    authoritative copy of the files used by all of the
	    <acronym>NIS</acronym> clients.  The
	    <filename>passwd</filename>, <filename>group</filename>,
	    and other various files used by <acronym>NIS</acronym>
	    clients are stored on the master server.  While it is
	    possible for one machine to be an <acronym>NIS</acronym>
	    master server for more than one <acronym>NIS</acronym>
	    domain, this type of configuration will not be covered in
	    this chapter as it assumes a relatively small-scale
	    <acronym>NIS</acronym> environment.</para>
	</listitem>

	<listitem>
	  <para><acronym>NIS</acronym> slave servers</para>

	  <para><acronym>NIS</acronym> slave servers maintain copies
	    of the <acronym>NIS</acronym> master's data files in
	    order to provide redundancy.  Slave servers also help to
	    balance the load of the master server as
	    <acronym>NIS</acronym> clients always attach to the
	    <acronym>NIS</acronym> server which responds
	    first.</para>
	</listitem>

	<listitem>
	  <para><acronym>NIS</acronym> clients</para>

	  <para><acronym>NIS</acronym> clients authenticate
	    against the <acronym>NIS</acronym> server during log
	    on.</para>
	</listitem>
      </itemizedlist>

      <para>Information in many files can be shared using
	<acronym>NIS</acronym>.  The
	<filename>master.passwd</filename>,
	<filename>group</filename>, and <filename>hosts</filename>
	files are commonly shared via <acronym>NIS</acronym>.
	Whenever a process on a client needs information that would
	normally be found in these files locally, it makes a query to
	the <acronym>NIS</acronym> server that it is bound to
	instead.</para>
    </sect2>

    <sect2>
      <title>Planning Considerations</title>

      <para>This section describes a sample <acronym>NIS</acronym>
	environment which consists of 15 &os; machines with no
	centralized point of administration.  Each machine has its own
	<filename>/etc/passwd</filename> and
	<filename>/etc/master.passwd</filename>.  These files are kept
	in sync with each other only through manual intervention.
	Currently, when a user is added to the lab, the process must
	be repeated on all 15 machines.</para>

      <para>The configuration of the lab will be as follows:</para>

      <informaltable frame="none" pgwide="1">
	<tgroup cols="3">
	  <thead>
	    <row>
	      <entry>Machine name</entry>
	      <entry><acronym>IP</acronym> address</entry>
	      <entry>Machine role</entry>
	    </row>
	  </thead>

	  <tbody>
	    <row>
	      <entry><systemitem>ellington</systemitem></entry>
	      <entry><systemitem
		  class="ipaddress">10.0.0.2</systemitem></entry>
	      <entry><acronym>NIS</acronym> master</entry>
	    </row>

	    <row>
	      <entry><systemitem>coltrane</systemitem></entry>
	      <entry><systemitem
		  class="ipaddress">10.0.0.3</systemitem></entry>
	      <entry><acronym>NIS</acronym> slave</entry>
	    </row>

	    <row>
	      <entry><systemitem>basie</systemitem></entry>
	      <entry><systemitem
		  class="ipaddress">10.0.0.4</systemitem></entry>
	      <entry>Faculty workstation</entry>
	    </row>

	    <row>
	      <entry><systemitem>bird</systemitem></entry>
	      <entry><systemitem
		  class="ipaddress">10.0.0.5</systemitem></entry>
	      <entry>Client machine</entry>
	    </row>

	    <row>
	      <entry><systemitem>cli[1-11]</systemitem></entry>
	      <entry>
		<systemitem
		  class="ipaddress">10.0.0.[6-17]</systemitem></entry>
	      <entry>Other client machines</entry>
	    </row>
	  </tbody>
	</tgroup>
      </informaltable>

      <para>If this is the first time an <acronym>NIS</acronym>
	scheme is being developed, it should be thoroughly planned
	ahead of time.  Regardless of network size, several decisions
	need to be made as part of the planning process.</para>

      <sect3>
	<title>Choosing a <acronym>NIS</acronym> Domain Name</title>

	<indexterm>
	  <primary>NIS</primary>
	  <secondary>domain name</secondary>
	</indexterm>
	<para>When a client broadcasts its requests for info, it
	  includes the name of the <acronym>NIS</acronym> domain that
	  it is part of.  This is how multiple servers on one network
	  can tell which server should answer which request.  Think of
	  the <acronym>NIS</acronym> domain name as the name for a
	  group of hosts.</para>

	<para>Some organizations choose to use their Internet domain
	  name for their <acronym>NIS</acronym> domain name.  This is
	  not recommended as it can cause confusion when trying to
	  debug network problems.  The <acronym>NIS</acronym> domain
	  name should be unique within the network and it is helpful
	  if it describes the group of machines it represents.  For
	  example, the Art department at Acme Inc. might be in the
	  <quote>acme-art</quote> <acronym>NIS</acronym> domain.  This
	  example will use the domain name
	  <literal>test-domain</literal>.</para>

	<para>However, some non-&os; operating systems require the
	  <acronym>NIS</acronym> domain name to be the same as the
	  Internet domain name.  If one or more machines on the
	  network have this restriction, the Internet domain name
	  <emphasis>must</emphasis> be used as the
	  <acronym>NIS</acronym> domain name.</para>
      </sect3>

      <sect3>
	<title>Physical Server Requirements</title>

	<para>There are several things to keep in mind when choosing a
	  machine to use as a <acronym>NIS</acronym> server.  Since
	  <acronym>NIS</acronym> clients depend upon the availability
	  of the server, choose a machine that is not rebooted
	  frequently.  The <acronym>NIS</acronym> server should
	  ideally be a stand alone machine whose sole purpose is to be
	  an <acronym>NIS</acronym> server.  If the network is not
	  heavily used, it is acceptable to put the
	  <acronym>NIS</acronym> server on a machine running other
	  services.  However, if the <acronym>NIS</acronym> server
	  becomes unavailable, it will adversely affect all
	  <acronym>NIS</acronym> clients.</para>
      </sect3>
    </sect2>

    <sect2>
      <title>Configuring the <acronym>NIS</acronym> Master
	Server</title>

      <para>The canonical copies of all <acronym>NIS</acronym> files
	are stored on the master server.  The databases used to store
	the information are called <acronym>NIS</acronym> maps.  In
	&os;, these maps are stored in
	<filename>/var/yp/[domainname]</filename> where
	<filename>[domainname]</filename> is the name of the
	<acronym>NIS</acronym> domain.  Since multiple domains are
	supported, it is possible to have several directories, one for
	each domain.  Each domain will have its own independent set of
	maps.</para>

      <para><acronym>NIS</acronym> master and slave servers handle all
	<acronym>NIS</acronym> requests through &man.ypserv.8;.  This
	daemon is responsible for receiving incoming requests from
	<acronym>NIS</acronym> clients, translating the requested
	domain and map name to a path to the corresponding database
	file, and transmitting data from the database back to the
	client.</para>

      <indexterm><primary>NIS</primary>
	<secondary>server configuration</secondary>
      </indexterm>
      <para>Setting up a master <acronym>NIS</acronym> server can be
	relatively straight forward, depending on environmental needs.
	Since &os; provides built-in <acronym>NIS</acronym> support,
	it only needs to be enabled by adding the following lines to
	<filename>/etc/rc.conf</filename>:</para>

      <programlisting>nisdomainname="<replaceable>test-domain</replaceable>"	<co xml:id="network-nis-co-domainname" />
nis_server_enable="YES"		<co xml:id="network-nis-co-server" />
nis_yppasswdd_enable="YES"	<co xml:id="network-nis-co-yppasswdd" /></programlisting>

      <calloutlist>
	<callout arearefs="network-nis-co-domainname">
	  <para>This line sets the <acronym>NIS</acronym> domain name
	    to <literal>test-domain</literal>.</para>
	</callout>

	<callout arearefs="network-nis-co-server">
	  <para>This automates the start up of the
	    <acronym>NIS</acronym> server processes when the system
	    boots.</para>
	</callout>

	<callout arearefs="network-nis-co-yppasswdd">
	  <para>This enables the &man.rpc.yppasswdd.8; daemon so that
	    users can change their <acronym>NIS</acronym> password
	    from a client machine.</para>
	</callout>
      </calloutlist>

      <para>Care must be taken in a multi-server domain where the
	server machines are also <acronym>NIS</acronym> clients.  It
	is generally a good idea to force the servers to bind to
	themselves rather than allowing them to broadcast bind
	requests and possibly become bound to each other.  Strange
	failure modes can result if one server goes down and others
	are dependent upon it.  Eventually, all the clients will time
	out and attempt to bind to other servers, but the delay
	involved can be considerable and the failure mode is still
	present since the servers might bind to each other all over
	again.</para>

      <para>A server that is also a client can be forced to bind to a
	particular server by adding these additional lines to
	<filename>/etc/rc.conf</filename>:</para>

<programlisting>nis_client_enable="YES"				<co xml:id="network-nis-co-client" />
nis_client_flags="-S <replaceable>test-domain</replaceable>,<replaceable>server</replaceable>"	<co xml:id="network-nis-co-clientflags" /></programlisting>

      <calloutlist>
	<callout arearefs="network-nis-co-client">
	  <para>This enables running client stuff as well.</para>
	</callout>

	<callout arearefs="network-nis-co-clientflags">
	  <para>This line sets the <acronym>NIS</acronym> domain name
	    to <literal>test-domain</literal> and bind to itself.</para>
	</callout>
      </calloutlist>

      <para>After saving the edits, type
	<command>/etc/netstart</command> to restart the network and
	apply the values defined in <filename>/etc/rc.conf</filename>.
	Before initializing the <acronym>NIS</acronym> maps, start
	&man.ypserv.8;:</para>

      <screen>&prompt.root; <userinput>service ypserv start</userinput></screen>

      <sect3>
	<title>Initializing the <acronym>NIS</acronym> Maps</title>

	<indexterm>
	  <primary>NIS</primary>
	  <secondary>maps</secondary>
	</indexterm>
	<para><acronym>NIS</acronym> maps are generated from the
	  configuration files in <filename>/etc</filename> on the
	  <acronym>NIS</acronym> master, with one exception:
	  <filename>/etc/master.passwd</filename>.  This is to prevent
	  the propagation of passwords to all the servers in the
	  <acronym>NIS</acronym> domain.  Therefore, before the
	  <acronym>NIS</acronym> maps are initialized, configure the
	  primary password files:</para>

	<screen>&prompt.root; <userinput>cp /etc/master.passwd /var/yp/master.passwd</userinput>
&prompt.root; <userinput>cd /var/yp</userinput>
&prompt.root; <userinput>vi master.passwd</userinput></screen>

	<para>It is advisable to remove all entries for system
	  accounts as well as any user accounts that do not need to be
	  propagated to the <acronym>NIS</acronym> clients, such as
	  the <systemitem class="username">root</systemitem> and any
	  other administrative accounts.</para>

	<note>
	  <para>Ensure that the
	    <filename>/var/yp/master.passwd</filename> is neither
	    group or world readable by setting its permissions to
	    <literal>600</literal>.</para>
	</note>

	<para>After completing this task, initialize the
	  <acronym>NIS</acronym> maps.  &os; includes the
	  &man.ypinit.8; script to do this.  When generating maps
	  for the master server, include <option>-m</option> and
	  specify the <acronym>NIS</acronym> domain name:</para>

	<screen>ellington&prompt.root; <userinput>ypinit -m test-domain</userinput>
Server Type: MASTER Domain: test-domain
Creating an YP server will require that you answer a few questions.
Questions will all be asked at the beginning of the procedure.
Do you want this procedure to quit on non-fatal errors? [y/n: n] <userinput>n</userinput>
Ok, please remember to go back and redo manually whatever fails.
If not, something might not work.
At this point, we have to construct a list of this domains YP servers.
rod.darktech.org is already known as master server.
Please continue to add any slave servers, one per line. When you are
done with the list, type a &lt;control D&gt;.
master server   :  ellington
next host to add:  <userinput>coltrane</userinput>
next host to add:  <userinput>^D</userinput>
The current list of NIS servers looks like this:
ellington
coltrane
Is this correct?  [y/n: y] <userinput>y</userinput>

[..output from map generation..]

NIS Map update completed.
ellington has been setup as an YP master server without any errors.</screen>

	<para>This will create <filename>/var/yp/Makefile</filename>
	  from <filename>/var/yp/Makefile.dist</filename>.  By
	  default, this file assumes that the environment has a
	  single <acronym>NIS</acronym> server with only &os; clients.
	  Since <literal>test-domain</literal> has a slave server,
	  edit this line in <filename>/var/yp/Makefile</filename> so
	  that it begins with a  comment
	  (<literal>#</literal>):</para>

	<programlisting>NOPUSH = "True"</programlisting>
      </sect3>

      <sect3>
	<title>Adding New Users</title>

	<para>Every time a new user is created, the user account must
	  be added to the master <acronym>NIS</acronym> server and the
	  <acronym>NIS</acronym> maps rebuilt.  Until this occurs, the
	  new user will not be able to login anywhere except on the
	  <acronym>NIS</acronym> master.  For example, to add the new
	  user <systemitem class="username">jsmith</systemitem> to the
	  <literal>test-domain</literal> domain, run these commands on
	  the master server:</para>

	<screen>&prompt.root; <userinput>pw useradd jsmith</userinput>
&prompt.root; <userinput>cd /var/yp</userinput>
&prompt.root; <userinput>make test-domain</userinput></screen>

	<para>The user could also be added using <command>adduser
	    jsmith</command> instead of <command>pw useradd
	    smith</command>.</para>
      </sect3>
    </sect2>

    <sect2>
      <title>Setting up a <acronym>NIS</acronym> Slave Server</title>

      <indexterm>
	<primary>NIS</primary>
	<secondary>slave server</secondary>
      </indexterm>
      <para>To set up an <acronym>NIS</acronym> slave server, log on
	to the slave server and edit <filename>/etc/rc.conf</filename>
	as for the master server.  Do not generate any
	<acronym>NIS</acronym> maps, as these already exist on the
	master server.  When running <command>ypinit</command> on the
	slave server, use <option>-s</option> (for slave) instead of
	<option>-m</option> (for master).  This option requires the
	name of the <acronym>NIS</acronym> master in addition to the
	domain name, as  seen in this example:</para>

      <screen>coltrane&prompt.root; <userinput>ypinit -s ellington test-domain</userinput>

Server Type: SLAVE Domain: test-domain Master: ellington

Creating an YP server will require that you answer a few questions.
Questions will all be asked at the beginning of the procedure.

Do you want this procedure to quit on non-fatal errors? [y/n: n]  <userinput>n</userinput>

Ok, please remember to go back and redo manually whatever fails.
If not, something might not work.
There will be no further questions. The remainder of the procedure
should take a few minutes, to copy the databases from ellington.
Transferring netgroup...
ypxfr: Exiting: Map successfully transferred
Transferring netgroup.byuser...
ypxfr: Exiting: Map successfully transferred
Transferring netgroup.byhost...
ypxfr: Exiting: Map successfully transferred
Transferring master.passwd.byuid...
ypxfr: Exiting: Map successfully transferred
Transferring passwd.byuid...
ypxfr: Exiting: Map successfully transferred
Transferring passwd.byname...
ypxfr: Exiting: Map successfully transferred
Transferring group.bygid...
ypxfr: Exiting: Map successfully transferred
Transferring group.byname...
ypxfr: Exiting: Map successfully transferred
Transferring services.byname...
ypxfr: Exiting: Map successfully transferred
Transferring rpc.bynumber...
ypxfr: Exiting: Map successfully transferred
Transferring rpc.byname...
ypxfr: Exiting: Map successfully transferred
Transferring protocols.byname...
ypxfr: Exiting: Map successfully transferred
Transferring master.passwd.byname...
ypxfr: Exiting: Map successfully transferred
Transferring networks.byname...
ypxfr: Exiting: Map successfully transferred
Transferring networks.byaddr...
ypxfr: Exiting: Map successfully transferred
Transferring netid.byname...
ypxfr: Exiting: Map successfully transferred
Transferring hosts.byaddr...
ypxfr: Exiting: Map successfully transferred
Transferring protocols.bynumber...
ypxfr: Exiting: Map successfully transferred
Transferring ypservers...
ypxfr: Exiting: Map successfully transferred
Transferring hosts.byname...
ypxfr: Exiting: Map successfully transferred

coltrane has been setup as an YP slave server without any errors.
Remember to update map ypservers on ellington.</screen>

      <para>This will generate a directory on the slave server called
	<filename>/var/yp/test-domain</filename> which contains copies
	of the <acronym>NIS</acronym> master server's maps.  Adding
	these <filename>/etc/crontab</filename> entries on each slave
	server will force the slaves to sync their maps with the maps
	on the master server:</para>

      <programlisting>20      *       *       *       *       root   /usr/libexec/ypxfr passwd.byname
21      *       *       *       *       root   /usr/libexec/ypxfr passwd.byuid</programlisting>

      <para>These entries are not mandatory because the master server
	automatically attempts to push any map changes to its slaves.
	However, since clients may depend upon the slave server to
	provide correct password information, it is recommended to
	force frequent password map updates.  This is especially
	important on busy networks where map updates might not always
	complete.</para>

      <para>To finish the configuration, run
	<command>/etc/netstart</command> on the slave server in order
	to start the <acronym>NIS</acronym> services.</para>
    </sect2>

    <sect2>
      <title>Setting Up an <acronym>NIS</acronym> Client</title>

      <para>An <acronym>NIS</acronym> client binds to an
	<acronym>NIS</acronym> server using &man.ypbind.8;.  This
	daemon broadcasts RPC requests on the local network.  These
	requests specify the domain name configured on the client.  If
	an <acronym>NIS</acronym> server in the same domain receives
	one of the broadcasts, it will respond to
	<application>ypbind</application>, which will record the
	server's address.  If there are several servers available,
	the client will use the address of the first server to respond
	and will direct all of its <acronym>NIS</acronym> requests to
	that server.  The client will automatically
	<application>ping</application> the server on a regular basis
	to make sure it is still available.  If it fails to receive a
	reply within a reasonable amount of time,
	<application>ypbind</application> will mark the domain as
	unbound and begin broadcasting again in the hopes of locating
	another server.</para>

      <indexterm><primary>NIS</primary>
	<secondary>client configuration</secondary>
      </indexterm>

      <para>To configure a &os; machine to be an
	<acronym>NIS</acronym> client:</para>

      <procedure>
	<step>
	  <para>Edit <filename>/etc/rc.conf</filename> and add the
	    following lines in order to set the
	    <acronym>NIS</acronym> domain name and start
	    &man.ypbind.8; during network startup:</para>

	  <programlisting>nisdomainname="test-domain"
nis_client_enable="YES"</programlisting>
	</step>

	<step>
	  <para>To import all possible password entries from the
	    <acronym>NIS</acronym> server, use
	    <command>vipw</command> to remove all user accounts
	    except one from <filename>/etc/master.passwd</filename>.
	    When removing the accounts, keep in mind that at least one
	    local account should remain and this account should be a
	    member of <systemitem
	      class="groupname">wheel</systemitem>.  If there is a
	    problem with <acronym>NIS</acronym>, this local account
	    can be used to log in remotely, become the superuser, and
	    fix the problem.  Before saving the edits, add the
	    following line to the end of the file:</para>

	  <programlisting>+:::::::::</programlisting>

	  <para>This line configures the client to provide anyone with
	    a valid account in the <acronym>NIS</acronym> server's
	    password maps an account on the client.  There are many
	    ways to configure the <acronym>NIS</acronym> client by
	    modifying this line.  One method is described in <xref
	      linkend="network-netgroups"/>.  For more detailed
	    reading, refer to the book
	    <literal>Managing NFS and NIS</literal>, published by
	    O'Reilly Media.</para>
	</step>

	<step>
	  <para>To import all possible group entries from the
	    <acronym>NIS</acronym> server, add this line to
	    <filename>/etc/group</filename>:</para>

	  <programlisting>+:*::</programlisting>
	</step>
      </procedure>

      <para>To start the <acronym>NIS</acronym> client immediately,
	execute the following commands as the superuser:</para>

      <screen>&prompt.root; <userinput>/etc/netstart</userinput>
&prompt.root; <userinput>service ypbind start</userinput></screen>

      <para>After completing these steps, running
	<command>ypcat passwd</command> on the client should show
	the server's <filename>passwd</filename> map.</para>
    </sect2>

    <sect2>
      <title><acronym>NIS</acronym> Security</title>

      <para>Since <acronym>RPC</acronym> is a broadcast-based service,
	any system running <application>ypbind</application> within
	the same domain can retrieve the contents of the
	<acronym>NIS</acronym> maps.  To prevent unauthorized
	transactions, &man.ypserv.8; supports a feature called
	<quote>securenets</quote> which can be used to restrict access
	to a given set of hosts.  By default, this information is
	stored in <filename>/var/yp/securenets</filename>, unless
	&man.ypserv.8; is started with <option>-p</option> and an
	alternate path.  This file contains entries that consist of a
	network specification and a network mask separated by white
	space.  Lines starting with <literal>#</literal> are
	considered to be comments.  A sample
	<filename>securenets</filename> might look like this:</para>

      <programlisting># allow connections from local host -- mandatory
127.0.0.1     255.255.255.255
# allow connections from any host
# on the 192.168.128.0 network
192.168.128.0 255.255.255.0
# allow connections from any host
# between 10.0.0.0 to 10.0.15.255
# this includes the machines in the testlab
10.0.0.0      255.255.240.0</programlisting>

      <para>If &man.ypserv.8; receives a request from an address that
	matches one of these rules, it will process the request
	normally.  If the address fails to match a rule, the request
	will be ignored and a warning message will be logged.  If the
	<filename>securenets</filename> does not exist,
	<command>ypserv</command> will allow connections from any
	host.</para>

      <para><xref linkend="tcpwrappers"/> is an alternate mechanism
	for providing access control instead of
	<filename>securenets</filename>.  While either access control
	mechanism adds some security, they are both vulnerable to
	<quote><acronym>IP</acronym> spoofing</quote> attacks.  All
	<acronym>NIS</acronym>-related traffic should be blocked at
	the firewall.</para>

      <para>Servers using <filename>securenets</filename>
	may fail to serve legitimate <acronym>NIS</acronym> clients
	with archaic TCP/IP implementations.  Some of these
	implementations set all host bits to zero when doing
	broadcasts or fail to observe the subnet mask when
	calculating the broadcast address.  While some of these
	problems can be fixed by changing the client configuration,
	other problems may force the retirement of these client
	systems or the abandonment of
	<filename>securenets</filename>.</para>

      <indexterm><primary>TCP Wrapper</primary></indexterm>
      <para>The use of <application>TCP Wrapper</application>
	increases the latency of the <acronym>NIS</acronym> server.
	The additional delay may be long enough to cause timeouts in
	client programs, especially in busy networks with slow
	<acronym>NIS</acronym> servers.  If one or more clients suffer
	from latency, convert those clients into
	<acronym>NIS</acronym> slave servers and force them to bind to
	themselves.</para>

      <sect3>
	<title>Barring Some Users</title>

	<para>In this example, the <systemitem>basie</systemitem>
	  system is a faculty workstation within the
	  <acronym>NIS</acronym> domain.  The
	  <filename>passwd</filename> map on the master
	  <acronym>NIS</acronym> server contains accounts for both
	  faculty and students.  This section demonstrates how to
	  allow faculty logins on this system while refusing student
	  logins.</para>

	<para>To prevent specified users from logging on to a system,
	  even if they are present in the <acronym>NIS</acronym>
	  database, use <command>vipw</command> to add
	  <literal>-<replaceable>username</replaceable></literal> with
	  the correct number of colons towards the end of
	  <filename>/etc/master.passwd</filename> on the client,
	  where <replaceable>username</replaceable> is the username of
	  a user to bar from logging in.  The line with the blocked
	  user must be before the <literal>+</literal> line that
	  allows <acronym>NIS</acronym> users.  In this example,
	  <systemitem class="username">bill</systemitem> is barred
	  from logging on to <systemitem>basie</systemitem>:</para>

	<screen>basie&prompt.root; <userinput>cat /etc/master.passwd</userinput>
root:[password]:0:0::0:0:The super-user:/root:/bin/csh
toor:[password]:0:0::0:0:The other super-user:/root:/bin/sh
daemon:*:1:1::0:0:Owner of many system processes:/root:/usr/sbin/nologin
operator:*:2:5::0:0:System &amp;:/:/usr/sbin/nologin
bin:*:3:7::0:0:Binaries Commands and Source,,,:/:/usr/sbin/nologin
tty:*:4:65533::0:0:Tty Sandbox:/:/usr/sbin/nologin
kmem:*:5:65533::0:0:KMem Sandbox:/:/usr/sbin/nologin
games:*:7:13::0:0:Games pseudo-user:/usr/games:/usr/sbin/nologin
news:*:8:8::0:0:News Subsystem:/:/usr/sbin/nologin
man:*:9:9::0:0:Mister Man Pages:/usr/share/man:/usr/sbin/nologin
bind:*:53:53::0:0:Bind Sandbox:/:/usr/sbin/nologin
uucp:*:66:66::0:0:UUCP pseudo-user:/var/spool/uucppublic:/usr/libexec/uucp/uucico
xten:*:67:67::0:0:X-10 daemon:/usr/local/xten:/usr/sbin/nologin
pop:*:68:6::0:0:Post Office Owner:/nonexistent:/usr/sbin/nologin
nobody:*:65534:65534::0:0:Unprivileged user:/nonexistent:/usr/sbin/nologin
-bill:::::::::
+:::::::::

basie&prompt.root;</screen>
      </sect3>
    </sect2>

    <sect2 xml:id="network-netgroups">
      <!--
      <sect2info>
	<authorgroup>
	  <author>
	    <firstname>Udo</firstname>
	    <surname>Erdelhoff</surname>
	    <contrib>Contributed by </contrib>
	  </author>
	</authorgroup>
      </sect2info>
      -->

      <title>Using Netgroups</title>

      <indexterm><primary>netgroups</primary></indexterm>

      <para>Barring specified users from logging on to individual
	systems becomes unscaleable on larger networks and quickly
	loses the main benefit of <acronym>NIS</acronym>:
	<emphasis>centralized</emphasis> administration.</para>

      <para>Netgroups were developed to handle large, complex networks
	with hundreds of users and machines.  Their use is comparable
	to &unix; groups, where the main difference is the lack of a
	numeric ID and the ability to define a netgroup by including
	both user accounts and other netgroups.</para>

      <para>To expand on the example used in this chapter, the
	<acronym>NIS</acronym> domain will be extended to add the
	users and systems shown in Tables 28.2 and 28.3:</para>

      <table frame="none" pgwide="1">
	<title>Additional Users</title>

	<tgroup cols="2">
	  <thead>
	    <row>
	      <entry>User Name(s)</entry>
	      <entry>Description</entry>
	    </row>
	  </thead>

	  <tbody>
	    <row>
	      <entry><systemitem class="username">alpha</systemitem>,
		<systemitem class="username">beta</systemitem></entry>
	      <entry>IT department employees</entry>
	    </row>

	    <row>
	      <entry><systemitem
		  class="username">charlie</systemitem>, <systemitem
		  class="username">delta</systemitem></entry>
	      <entry>IT department apprentices</entry>
	    </row>

	    <row>
	      <entry><systemitem class="username">echo</systemitem>,
		<systemitem class="username">foxtrott</systemitem>,
		<systemitem class="username">golf</systemitem>,
		...</entry>
	      <entry>employees</entry>
	    </row>

	    <row>
	      <entry><systemitem class="username">able</systemitem>,
		<systemitem class="username">baker</systemitem>,
		...</entry>
	      <entry>interns</entry>
	    </row>
	  </tbody>
	</tgroup>
      </table>

      <table frame="none" pgwide="1">
	<title>Additional Systems</title>

	<tgroup cols="2">
	  <thead>
	    <row>
	      <entry>Machine Name(s)</entry>
	      <entry>Description</entry>
	    </row>
	  </thead>

	  <tbody>
	    <row>
	      <!--  Names taken from "Good Omens" by Neil Gaiman and Terry
		    Pratchett.  Many thanks for a brilliant book.  -->
	      <entry><systemitem>war</systemitem>,
		<systemitem>death</systemitem>,
		<systemitem>famine</systemitem>,
		<systemitem>pollution</systemitem></entry>
	      <entry>Only IT employees are allowed to log onto these
		servers.</entry>
	    </row>

	    <row>
	      <!-- gluttony was omitted because it was too fat -->
	      <entry><systemitem>pride</systemitem>,
		<systemitem>greed</systemitem>,
		<systemitem>envy</systemitem>,
		<systemitem>wrath</systemitem>,
		<systemitem>lust</systemitem>,
		<systemitem>sloth</systemitem></entry>
	      <entry>All members of the IT department are allowed to
		login onto these servers.</entry>
	    </row>

	    <row>
	      <entry><systemitem>one</systemitem>,
		<systemitem>two</systemitem>,
		<systemitem>three</systemitem>,
		<systemitem>four</systemitem>,
		...</entry>
	      <entry>Ordinary workstations used by
		employees.</entry>
	    </row>

	    <row>
	      <entry><systemitem>trashcan</systemitem></entry>
	      <entry>A very old machine without any critical data.
		Even interns are allowed to use this system.</entry>
	    </row>
	  </tbody>
	</tgroup>
      </table>

      <para>When using netgroups to configure this scenario, each user
	is assigned to one or more netgroups and logins are then
	allowed or forbidden for all members of the netgroup.  When
	adding a new machine, login restrictions must be defined for
	all netgroups.  When a new user is added, the account must be
	added to one or more netgroups.  If the
	<acronym>NIS</acronym> setup is planned carefully, only one
	central configuration file needs modification to grant or deny
	access to machines.</para>

      <para>The first step is the initialization of the
	<acronym>NIS</acronym> <literal>netgroup</literal> map.  In
	&os;, this map is not created by default.  On the
	<acronym>NIS</acronym> master server, use an editor to create
	a map named <filename>/var/yp/netgroup</filename>.</para>

      <para>This example creates four netgroups to represent IT
	employees, IT apprentices, employees, and interns:</para>

      <programlisting>IT_EMP  (,alpha,test-domain)    (,beta,test-domain)
IT_APP  (,charlie,test-domain)  (,delta,test-domain)
USERS   (,echo,test-domain)     (,foxtrott,test-domain) \
        (,golf,test-domain)
INTERNS (,able,test-domain)     (,baker,test-domain)</programlisting>

      <para>Each entry configures a netgroup.  The first column in an
	entry is the name of the netgroup.  Each set of brackets
	represents  either a group of one or more users or the name of
	another netgroup.  When specifying a user, the three
	comma-delimited fields inside each group represent:</para>

      <orderedlist>
	<listitem>
	  <para>The name of the host(s) where the other fields
	    representing the user are valid.  If a hostname is not
	    specified, the entry is valid on all hosts.</para>
	</listitem>

	<listitem>
	  <para>The name of the account that belongs to this
	    netgroup.</para>
	</listitem>

	<listitem>
	  <para>The <acronym>NIS</acronym> domain for the account.
	    Accounts may be imported from other <acronym>NIS</acronym>
	    domains into a netgroup.</para>
	</listitem>
      </orderedlist>

      <para>If a group contains multiple users, separate each user
	with  whitespace.  Additionally, each field may contain
	wildcards.  See &man.netgroup.5; for details.</para>

      <indexterm><primary>netgroups</primary></indexterm>
      <para>Netgroup names longer than 8 characters should not be
	used.  The names are case sensitive and using capital letters
	for netgroup names is an easy way to distinguish between user,
	machine and netgroup names.</para>

      <para>Some non-&os; <acronym>NIS</acronym> clients cannot
	handle netgroups containing more than 15 entries.  This
	limit may be circumvented by creating several sub-netgroups
	with 15 users or fewer and a real netgroup consisting of the
	sub-netgroups, as seen in this example:</para>

      <programlisting>BIGGRP1  (,joe1,domain)  (,joe2,domain)  (,joe3,domain) [...]
BIGGRP2  (,joe16,domain)  (,joe17,domain) [...]
BIGGRP3  (,joe31,domain)  (,joe32,domain)
BIGGROUP  BIGGRP1 BIGGRP2 BIGGRP3</programlisting>

      <para>Repeat this process if more than 225 (15 times 15) users
	exist within a single netgroup.</para>

      <para>To activate and distribute the new
	<acronym>NIS</acronym> map:</para>

      <screen>ellington&prompt.root; <userinput>cd /var/yp</userinput>
ellington&prompt.root; <userinput>make</userinput></screen>

      <para>This will generate the three <acronym>NIS</acronym> maps
	<filename>netgroup</filename>,
	<filename>netgroup.byhost</filename> and
	<filename>netgroup.byuser</filename>.  Use the map key option
	of &man.ypcat.1; to check if the new <acronym>NIS</acronym>
	maps are available:</para>

      <screen>ellington&prompt.user; <userinput>ypcat -k netgroup</userinput>
ellington&prompt.user; <userinput>ypcat -k netgroup.byhost</userinput>
ellington&prompt.user; <userinput>ypcat -k netgroup.byuser</userinput></screen>

      <para>The output of the first command should resemble the
	contents of <filename>/var/yp/netgroup</filename>.  The second
	command only produces output if host-specific netgroups were
	created.  The third command is used to get the list of
	netgroups for a user.</para>

      <para>To configure a client, use &man.vipw.8; to specify the
	name  of the netgroup.  For example, on the server named
	<systemitem>war</systemitem>,  replace this line:</para>

      <programlisting>+:::::::::</programlisting>

      <para>with</para>

      <programlisting>+@IT_EMP:::::::::</programlisting>

      <para>This specifies that only the users defined in the netgroup
	<literal>IT_EMP</literal> will be imported into this system's
	password database and only those users are allowed to login to
	this system.</para>

      <para>This configuration also applies to the
	<literal>~</literal> function of the shell and all routines
	which convert between user names and numerical user IDs.  In
	other words,
	<command>cd ~<replaceable>user</replaceable></command> will
	not work, <command>ls -l</command> will show the numerical ID
	instead of the username, and <command>find . -user joe
	  -print</command> will fail with the message
	<errorname>No such user</errorname>.  To fix this, import all
	user entries without allowing them to login into the servers.
	This can be achieved by adding an extra line:</para>

      <programlisting>+:::::::::/usr/sbin/nologin</programlisting>

      <para>This line configures the client to import all entries but
	to replace the shell in those entries with
	<filename>/usr/sbin/nologin</filename>.</para>

      <!-- Been there, done that, got the scars to prove it - ue -->
      <para>Make sure that extra line is placed
	<emphasis>after</emphasis>
	<literal>+@IT_EMP:::::::::</literal>.  Otherwise, all user
	accounts imported from <acronym>NIS</acronym> will have
	<filename>/usr/sbin/nologin</filename> as their login
	shell and no one will be able to login to the system.</para>

      <para>To configure the less important servers, replace the old
	<literal>+:::::::::</literal> on the servers with these
	lines:</para>

      <programlisting>+@IT_EMP:::::::::
+@IT_APP:::::::::
+:::::::::/usr/sbin/nologin</programlisting>

      <para>The corresponding lines for the workstations
	would be:</para>

      <programlisting>+@IT_EMP:::::::::
+@USERS:::::::::
+:::::::::/usr/sbin/nologin</programlisting>

      <para>NIS supports the creation of netgroups from other
	netgroups which can be useful if the policy regarding user
	access changes.  One possibility is the creation of role-based
	netgroups.  For example, one might create a netgroup called
	<literal>BIGSRV</literal> to define the login restrictions for
	the important servers, another netgroup called
	<literal>SMALLSRV</literal> for the less important servers,
	and a third netgroup called <literal>USERBOX</literal> for the
	workstations.  Each of these netgroups contains the netgroups
	that are allowed to login onto these machines.  The new
	entries for the <acronym>NIS</acronym>
	<literal>netgroup</literal> map would look like this:</para>

      <programlisting>BIGSRV    IT_EMP  IT_APP
SMALLSRV  IT_EMP  IT_APP  ITINTERN
USERBOX   IT_EMP  ITINTERN USERS</programlisting>

      <para>This method of defining login restrictions works
	reasonably well when it is possible to define groups of
	machines with identical restrictions.  Unfortunately, this is
	the exception and not the rule.  Most of the time, the ability
	to define login restrictions on a per-machine basis is
	required.</para>

      <para>Machine-specific netgroup definitions are another
	possibility to deal with the policy changes.  In this
	scenario, the <filename>/etc/master.passwd</filename> of each
	system contains two lines starting with <quote>+</quote>.
	The first line adds a netgroup with the accounts allowed to
	login onto this machine and the second line adds all other
	accounts with <filename>/usr/sbin/nologin</filename> as shell.
	It is recommended to use the <quote>ALL-CAPS</quote> version
	of the hostname as the name of the netgroup:</para>

      <programlisting>+@<replaceable>BOXNAME</replaceable>:::::::::
+:::::::::/usr/sbin/nologin</programlisting>

      <para>Once this task is completed on all the machines, there is
	no longer a need to modify the local versions of
	<filename>/etc/master.passwd</filename> ever again.  All
	further changes can be handled by modifying the
	<acronym>NIS</acronym> map.  Here is an example of a possible
	<literal>netgroup</literal> map for this scenario:</para>

      <programlisting># Define groups of users first
IT_EMP    (,alpha,test-domain)    (,beta,test-domain)
IT_APP    (,charlie,test-domain)  (,delta,test-domain)
DEPT1     (,echo,test-domain)     (,foxtrott,test-domain)
DEPT2     (,golf,test-domain)     (,hotel,test-domain)
DEPT3     (,india,test-domain)    (,juliet,test-domain)
ITINTERN  (,kilo,test-domain)     (,lima,test-domain)
D_INTERNS (,able,test-domain)     (,baker,test-domain)
#
# Now, define some groups based on roles
USERS     DEPT1   DEPT2     DEPT3
BIGSRV    IT_EMP  IT_APP
SMALLSRV  IT_EMP  IT_APP    ITINTERN
USERBOX   IT_EMP  ITINTERN  USERS
#
# And a groups for a special tasks
# Allow echo and golf to access our anti-virus-machine
SECURITY  IT_EMP  (,echo,test-domain)  (,golf,test-domain)
#
# machine-based netgroups
# Our main servers
WAR       BIGSRV
FAMINE    BIGSRV
# User india needs access to this server
POLLUTION  BIGSRV  (,india,test-domain)
#
# This one is really important and needs more access restrictions
DEATH     IT_EMP
#
# The anti-virus-machine mentioned above
ONE       SECURITY
#
# Restrict a machine to a single user
TWO       (,hotel,test-domain)
# [...more groups to follow]</programlisting>

      <para>It may not always be advisable
	to use machine-based netgroups.  When deploying a couple of
	dozen or hundreds of systems,
	role-based netgroups instead of machine-based netgroups may be
	used to keep the size of the <acronym>NIS</acronym> map within
	reasonable limits.</para>
    </sect2>

    <sect2>
      <title>Password Formats</title>

      <indexterm>
	<primary>NIS</primary>
	  <secondary>password formats</secondary>
      </indexterm>
      <para><acronym>NIS</acronym> requires that all hosts within an
	<acronym>NIS</acronym> domain use the same format for
	encrypting passwords.  If users have trouble authenticating on
	an <acronym>NIS</acronym> client, it may be due to a differing
	password format.  In a heterogeneous network, the format must
	be supported by all operating systems, where
	<acronym>DES</acronym> is the lowest common standard.</para>

      <para>To check which format a server or client is using, look
	at this section of
	<filename>/etc/login.conf</filename>:</para>

      <programlisting>default:\
	:passwd_format=des:\
	:copyright=/etc/COPYRIGHT:\
	[Further entries elided]</programlisting>

      <para>In this example, the system is using the
	<acronym>DES</acronym> format.  Other possible values are
	<literal>blf</literal> for Blowfish and <literal>md5</literal>
	for MD5 encrypted passwords.</para>

      <para>If the format on a host needs to be edited to match the
	one  being used in the <acronym>NIS</acronym> domain, the
	login capability database must be rebuilt after saving the
	change:</para>

      <screen>&prompt.root; <userinput>cap_mkdb /etc/login.conf</userinput></screen>

      <note>
	<para>The format of passwords for existing user accounts will
	  not be updated until each user changes their password
	  <emphasis>after</emphasis> the login capability database is
	  rebuilt.</para>
      </note>
    </sect2>
  </sect1>

  <sect1 xml:id="network-ldap">
    <info>
      <title>Lightweight Directory Access Protocol
	(<acronym>LDAP</acronym>)</title>

      <authorgroup>
	<author>
	  <personname>
	    <firstname>Tom</firstname>
	    <surname>Rhodes</surname>
	  </personname>
	  <contrib>Originally contributed by </contrib>
	</author>
      </authorgroup>
      <authorgroup>
	<author>
	  <personname>
	    <firstname>Rocky</firstname>
	    <surname>Hotas</surname>
	  </personname>
	  <contrib>Updates by </contrib>
	</author>
      </authorgroup>
    </info>

    <indexterm><primary>LDAP</primary></indexterm>

    <para>The Lightweight Directory Access Protocol
      (<acronym>LDAP</acronym>) is an application layer protocol used
      to access, modify, and authenticate objects using a distributed
      directory information service.  Think of it as a phone or record
      book which stores several levels of hierarchical, homogeneous
      information.  It is used in Active Directory and
      <application>OpenLDAP</application> networks and allows users to
      access to several levels of internal information utilizing a
      single account.  For example, email authentication, pulling
      employee contact information, and internal website
      authentication might all make use of a single user account in
      the <acronym>LDAP</acronym> server's record base.</para>

    <para>This section provides a quick start guide for configuring an
      <acronym>LDAP</acronym> server on a &os; system.  It assumes
      that the administrator already has a design plan which includes
      the type of information to store, what that information will be
      used for, which users should have access to that information,
      and how to secure this information from unauthorized
      access.</para>

    <sect2>
      <title><acronym>LDAP</acronym> Terminology and Structure</title>

      <para><acronym>LDAP</acronym> uses several terms which should be
	understood before starting the configuration.  All directory
	entries consist of a group of
	<firstterm>attributes</firstterm>.  Each of these attribute
	sets contains a unique identifier known as a
	<firstterm>Distinguished Name</firstterm>
	(<acronym>DN</acronym>) which is normally built from several
	other attributes such as the common or
	<firstterm>Relative Distinguished Name</firstterm>
	(<acronym>RDN</acronym>).  Similar to how directories have
	absolute and relative paths, consider a <acronym>DN</acronym>
	as an absolute path and the <acronym>RDN</acronym> as the
	relative path.</para>

      <para>An example <acronym>LDAP</acronym> entry looks like the
	following.  This example searches for the entry for the
	specified user account (<literal>uid</literal>),
	organizational unit (<literal>ou</literal>), and organization
	(<literal>o</literal>):</para>

      <screen>&prompt.user; <userinput>ldapsearch -xb "uid=<replaceable>trhodes</replaceable>,ou=<replaceable>users</replaceable>,o=<replaceable>example.com</replaceable>"</userinput>
# extended LDIF
#
# LDAPv3
# base &lt;uid=trhodes,ou=users,o=example.com&gt; with scope subtree
# filter: (objectclass=*)
# requesting: ALL
#

# trhodes, users, example.com
dn: uid=trhodes,ou=users,o=example.com
mail: trhodes@example.com
cn: Tom Rhodes
uid: trhodes
telephoneNumber: (123) 456-7890

# search result
search: 2
result: 0 Success

# numResponses: 2
# numEntries: 1</screen>

      <para>This example entry shows the values for the
	<literal>dn</literal>, <literal>mail</literal>,
	<literal>cn</literal>, <literal>uid</literal>, and
	<literal>telephoneNumber</literal> attributes.  The
	<acronym>cn</acronym> attribute is the
	<acronym>RDN</acronym>.</para>

      <para>More information about <acronym>LDAP</acronym> and its
	terminology can be found at <uri
	  xlink:href="http://www.openldap.org/doc/admin24/intro.html">http://www.openldap.org/doc/admin24/intro.html</uri>.</para>
    </sect2>

    <sect2 xml:id="ldap-config">
      <title>Configuring an <acronym>LDAP</acronym> Server</title>

      <indexterm><primary>LDAP Server</primary></indexterm>

      <para>&os; does not provide a built-in <acronym>LDAP</acronym>
	server.  Begin the configuration by installing <package
	  role="port">net/openldap-server</package> package or
	port:</para>

      <screen>&prompt.root; <userinput>pkg install openldap-server</userinput></screen>

      <para>There is a large set of default options enabled in the
	<link xlink:href="&url.articles.linux-users;/software.html">
	  package</link>.  Review them by running
	<command>pkg info openldap-server</command>.  If they are not
	sufficient (for example if SQL support is needed), please
	consider recompiling the port using the appropriate <link
	  xlink:href="&url.books.handbook;/ports-using.html">framework</link>.</para>

      <para>The installation creates the directory
	<filename>/var/db/openldap-data</filename> to hold the data.
	The directory to store the certificates must be
	created:</para>

      <screen>&prompt.root; <userinput>mkdir /usr/local/etc/openldap/private</userinput></screen>

      <para>The next phase is to configure the Certificate Authority.
	The following commands must be executed from
	<filename>/usr/local/etc/openldap/private</filename>.  This is
	important as the file permissions need to be restrictive and
	users should not have access to these files.  More detailed
	information about certificates and their parameters can be
	found in <xref linkend="openssl"/>.  To create the
	Certificate Authority, start with this command and follow the
	prompts:</para>

      <screen>&prompt.root; <userinput>openssl req -days <replaceable>365</replaceable> -nodes -new -x509 -keyout ca.key -out ../ca.crt</userinput></screen>

      <para>The entries for the prompts may be generic
	<emphasis>except</emphasis> for the
	<literal>Common Name</literal>.  This entry must be
	<emphasis>different</emphasis> than the system hostname.  If
	this will be a self signed certificate, prefix the hostname
	with <literal>CA</literal> for Certificate Authority.</para>

      <para>The next task is to create a certificate signing request
	and a private key.  Input this command and follow the
	prompts:</para>

      <screen>&prompt.root; <userinput>openssl req -days <replaceable>365</replaceable> -nodes -new -keyout server.key -out server.csr</userinput></screen>

      <para>During the certificate generation process, be sure to
	correctly set the <literal>Common Name</literal> attribute.
	The Certificate Signing Request must be signed with the
	Certificate Authority in order to be used as a valid
	certificate:</para>

      <screen>&prompt.root; <userinput>openssl x509 -req -days <replaceable>365</replaceable> -in server.csr -out ../server.crt -CA ../ca.crt -CAkey ca.key -CAcreateserial</userinput></screen>

      <para>The final part of the certificate generation process is to
	generate and sign the client certificates:</para>

      <screen>&prompt.root; <userinput>openssl req -days <replaceable>365</replaceable> -nodes -new -keyout client.key -out client.csr</userinput>
&prompt.root; <userinput>openssl x509 -req -days 3650 -in client.csr -out ../client.crt -CA ../ca.crt -CAkey ca.key</userinput></screen>

      <para>Remember to use the same <literal>Common Name</literal>
	attribute when prompted.  When finished, ensure that a total
	of eight (8) new files have been generated through the
	proceeding commands.</para>

      <para>The daemon running the OpenLDAP server is
	<filename>slapd</filename>.  Its configuration is performed
	through <filename>slapd.ldif</filename>: the old
	<filename>slapd.conf</filename> has been deprecated by
	OpenLDAP.</para>

      <para><link
	  xlink:href="http://www.openldap.org/doc/admin24/slapdconf2.html">Configuration
	  examples</link> for <filename>slapd.ldif</filename> are
	available and can also be found in
	<filename>/usr/local/etc/openldap/slapd.ldif.sample</filename>.
	Options are documented in slapd-config(5).  Each section
	of <filename>slapd.ldif</filename>, like all the other LDAP
	attribute sets, is uniquely identified through a DN.  Be sure
	that no blank lines are left between the
	<literal>dn:</literal> statement and the desired end of the
	section.  In the following example, TLS will be used to
	implement a secure channel.  The first section represents the
	global configuration:</para>

      <programlisting>#
# See slapd-config(5) for details on configuration options.
# This file should NOT be world readable.
#
dn: cn=config
objectClass: olcGlobal
cn: config
#
#
# Define global ACLs to disable default read access.
#
olcArgsFile: /var/run/openldap/slapd.args
olcPidFile: /var/run/openldap/slapd.pid
olcTLSCertificateFile: /usr/local/etc/openldap/server.crt
olcTLSCertificateKeyFile: /usr/local/etc/openldap/private/server.key
olcTLSCACertificateFile: /usr/local/etc/openldap/ca.crt
#olcTLSCipherSuite: HIGH
olcTLSProtocolMin: 3.1
olcTLSVerifyClient: never</programlisting>

      <para>The Certificate Authority, server certificate and server
	private key files must be specified here.  It is recommended
	to let the clients choose the security cipher and omit option
	<literal>olcTLSCipherSuite</literal> (incompatible with TLS
	clients other than <filename>openssl</filename>).  Option
	<literal>olcTLSProtocolMin</literal> lets the server require a
	minimum security level: it is recommended.  While
	verification is mandatory for the server, it is not for the
	client: <literal>olcTLSVerifyClient: never</literal>.</para>

      <para>The second section is about the backend modules and can be
	configured as follows:</para>

      <programlisting>#
# Load dynamic backend modules:
#
dn: cn=module,cn=config
objectClass: olcModuleList
cn: module
olcModulepath:	/usr/local/libexec/openldap
olcModuleload:	back_mdb.la
#olcModuleload:	back_bdb.la
#olcModuleload:	back_hdb.la
#olcModuleload:	back_ldap.la
#olcModuleload:	back_passwd.la
#olcModuleload:	back_shell.la</programlisting>

      <para>The third section is devoted to load the needed
	<literal>ldif</literal> schemas to be used by the databases:
	they are essential.</para>

      <programlisting>dn: cn=schema,cn=config
objectClass: olcSchemaConfig
cn: schema

include: file:///usr/local/etc/openldap/schema/core.ldif
include: file:///usr/local/etc/openldap/schema/cosine.ldif
include: file:///usr/local/etc/openldap/schema/inetorgperson.ldif
include: file:///usr/local/etc/openldap/schema/nis.ldif</programlisting>

      <para>Next, the frontend configuration section:</para>

      <programlisting># Frontend settings
#
dn: olcDatabase={-1}frontend,cn=config
objectClass: olcDatabaseConfig
objectClass: olcFrontendConfig
olcDatabase: {-1}frontend
olcAccess: to * by * read
#
# Sample global access control policy:
#	Root DSE: allow anyone to read it
#	Subschema (sub)entry DSE: allow anyone to read it
#	Other DSEs:
#		Allow self write access
#		Allow authenticated users read access
#		Allow anonymous users to authenticate
#
#olcAccess: to dn.base="" by * read
#olcAccess: to dn.base="cn=Subschema" by * read
#olcAccess: to *
#	by self write
#	by users read
#	by anonymous auth
#
# if no access controls are present, the default policy
# allows anyone and everyone to read anything but restricts
# updates to rootdn.  (e.g., "access to * by * read")
#
# rootdn can always read and write EVERYTHING!
#
olcPasswordHash: {SSHA}
# {SSHA} is already the default for olcPasswordHash</programlisting>

      <para>Another section is devoted to the <emphasis>configuration
	  backend</emphasis>, the only way to later access the
	OpenLDAP server configuration is as a global
	super-user.</para>

      <programlisting>dn: olcDatabase={0}config,cn=config
objectClass: olcDatabaseConfig
olcDatabase: {0}config
olcAccess: to * by * none
olcRootPW: {SSHA}iae+lrQZILpiUdf16Z9KmDmSwT77Dj4U</programlisting>

      <para>The default administrator username is
	<literal>cn=config</literal>.  Type
	<filename>slappasswd</filename> in a shell, choose a password
	and use its hash in <literal>olcRootPW</literal>.  If this
	option is not specified now, before
	<filename>slapd.ldif</filename> is imported, no one will be
	later able to modify the
	<emphasis>global configuration</emphasis> section.</para>

      <para>The last section is about the database backend:</para>

      <programlisting>#######################################################################
# LMDB database definitions
#######################################################################
#
dn: olcDatabase=mdb,cn=config
objectClass: olcDatabaseConfig
objectClass: olcMdbConfig
olcDatabase: mdb
olcDbMaxSize: 1073741824
olcSuffix: dc=domain,dc=example
olcRootDN: cn=mdbadmin,dc=domain,dc=example
# Cleartext passwords, especially for the rootdn, should
# be avoided.  See slappasswd(8) and slapd-config(5) for details.
# Use of strong authentication encouraged.
olcRootPW: {SSHA}X2wHvIWDk6G76CQyCMS1vDCvtICWgn0+
# The database directory MUST exist prior to running slapd AND
# should only be accessible by the slapd and slap tools.
# Mode 700 recommended.
olcDbDirectory:	/var/db/openldap-data
# Indices to maintain
olcDbIndex: objectClass eq</programlisting>

      <para>This database hosts the <emphasis>actual
	  contents</emphasis> of the <acronym>LDAP</acronym>
	directory.  Types other than <literal>mdb</literal> are
	available.  Its super-user, not to be confused with the global
	one, is configured here: a (possibly custom) username in
	<literal>olcRootDN</literal> and the password hash in
	<literal>olcRootPW</literal>; <filename>slappasswd</filename>
	can be used as before.</para>

      <para>This <link
	  xlink:href="http://www.openldap.org/devel/gitweb.cgi?p=openldap.git;a=tree;f=tests/data/regressions/its8444;h=8a5e808e63b0de3d2bdaf2cf34fecca8577ca7fd;hb=HEAD">repository</link>
	contains four examples of <filename>slapd.ldif</filename>.  To
	convert an existing <filename>slapd.conf</filename> into
	<filename>slapd.ldif</filename>, refer to <link
	  xlink:href="http://www.openldap.org/doc/admin24/slapdconf2.html">this
	  page</link> (please note that this may introduce some
	unuseful options).</para>

      <para>When the configuration is completed,
	<filename>slapd.ldif</filename> must be placed in an empty
	directory.  It is recommended to create it as:</para>

      <screen>&prompt.root; <userinput>mkdir /usr/local/etc/openldap/slapd.d/</userinput></screen>

      <para>Import the configuration database:</para>

      <screen>&prompt.root; <userinput>/usr/local/sbin/slapadd -n0 -F /usr/local/etc/openldap/slapd.d/ -l /usr/local/etc/openldap/slapd.ldif</userinput></screen>

      <para>Start the <filename>slapd</filename> daemon:</para>

      <screen>&prompt.root; <userinput>/usr/local/libexec/slapd -F /usr/local/etc/openldap/slapd.d/</userinput></screen>

      <para>Option <literal>-d</literal> can be used for debugging,
	as specified in slapd(8).  To verify that the server is
	running and working:</para>

      <screen>&prompt.root; <userinput>ldapsearch -x -b '' -s base '(objectclass=*)' namingContexts</userinput>
# extended LDIF
#
# LDAPv3
# base &lt;&gt; with scope baseObject
# filter: (objectclass=*)
# requesting: namingContexts
#

#
dn:
namingContexts: dc=domain,dc=example

# search result
search: 2
result: 0 Success

# numResponses: 2
# numEntries: 1</screen>

      <para>The server must still be trusted.  If that has never been
	done before, follow these instructions.  Install the OpenSSL
	package or port:</para>

      <screen>&prompt.root; <userinput>pkg install openssl</userinput></screen>

      <para>From the directory where <filename>ca.crt</filename> is
	stored (in this example,
	<filename>/usr/local/etc/openldap</filename>), run:</para>

      <screen>&prompt.root; <userinput>c_rehash .</userinput></screen>

      <para>Both the CA and the server certificate are now correctly
	recognized in their respective roles.  To verify this, run
	this command from the <filename>server.crt</filename>
	directory:</para>

      <screen>&prompt.root; <userinput>openssl verify -verbose -CApath . server.crt</userinput></screen>

      <para>If <filename>slapd</filename> was running, restart it.  As
	stated in <filename>/usr/local/etc/rc.d/slapd</filename>, to
	properly run <filename>slapd</filename> at boot the
	following lines must be added to
	<filename>/etc/rc.conf</filename>:</para>

      <programlisting>lapd_enable="YES"
slapd_flags='-h "ldapi://%2fvar%2frun%2fopenldap%2fldapi/
ldap://0.0.0.0/"'
slapd_sockets="/var/run/openldap/ldapi"
slapd_cn_config="YES"</programlisting>

      <para><filename>slapd</filename> does not provide debugging at
	boot.  Check <filename>/var/log/debug.log</filename>,
	<filename>dmesg -a</filename> and
	<filename>/var/log/messages</filename> for this
	purpose.</para>

      <para>The following example adds the group
	<literal>team</literal> and the user <literal>john</literal>
	to the <systemitem
	  class="systemname">domain.example</systemitem>
	<acronym>LDAP</acronym> database, which is still empty.
	First, create the file
	<filename>domain.ldif</filename>:</para>

      <screen>&prompt.root; <userinput>cat domain.ldif</userinput>
dn: dc=domain,dc=example
objectClass: dcObject
objectClass: organization
o: domain.example
dc: domain

dn: ou=groups,dc=domain,dc=example
objectClass: top
objectClass: organizationalunit
ou: groups

dn: ou=users,dc=domain,dc=example
objectClass: top
objectClass: organizationalunit
ou: users

dn: cn=team,ou=groups,dc=domain,dc=example
objectClass: top
objectClass: posixGroup
cn: team
gidNumber: 10001

dn: uid=john,ou=users,dc=domain,dc=example
objectClass: top
objectClass: account
objectClass: posixAccount
objectClass: shadowAccount
cn: John McUser
uid: john
uidNumber: 10001
gidNumber: 10001
homeDirectory: /home/john/
loginShell: /usr/bin/bash
userPassword: secret</screen>

      <para>See the OpenLDAP documentation for more details.  Use
	<filename>slappasswd</filename> to replace the plain text
	password <literal>secret</literal> with a hash in
	<literal>userPassword</literal>.  The path specified as
	<literal>loginShell</literal> must exist in all the systems
	where <literal>john</literal> is allowed to login.  Finally,
	use the <literal>mdb</literal> administrator to modify the
	database:</para>

      <screen>&prompt.root; <userinput>ldapadd -W -D "cn=mdbadmin,dc=domain,dc=example" -f domain.ldif</userinput></screen>

      <para>Modifications to the <emphasis>global
	  configuration</emphasis> section can only be performed by
	the global super-user.  For example, assume that the option
	<literal>olcTLSCipherSuite: HIGH:MEDIUM:SSLv3</literal> was
	initially specified and must now be deleted.  First, create a
	file that contains the following:</para>

      <screen>&prompt.root; <userinput>cat <replaceable>global_mod</replaceable></userinput>
dn: cn=config
changetype: modify
delete: olcTLSCipherSuite</screen>

      <para>Then, apply the modifications:</para>

      <screen>&prompt.root; <userinput>ldapmodify -f global_mod -x -D "cn=config" -W</userinput></screen>

      <para>When asked, provide the password chosen in the
	<emphasis>configuration backend</emphasis> section.  The
	username is not required: here, <literal>cn=config</literal>
	represents the DN of the database section to be modified.
	Alternatively, use <literal>ldapmodify</literal> to delete a
	single line of the database, <literal>ldapdelete</literal> to
	delete a whole entry.</para>

      <para>If something goes wrong, or if the global super-user
	cannot access the configuration backend, it is possible to
	delete and re-write the whole configuration:</para>

      <screen>&prompt.root; <userinput>rm -rf /usr/local/etc/openldap/slapd.d/</userinput></screen>

      <para><filename>slapd.ldif</filename> can then be edited and
	imported again.  Please, follow this procedure only when no
	other solution is available.</para>

      <para>This is the configuration of the server only.  The same
	machine can also host an LDAP client, with its own separate
	configuration.</para>
    </sect2>
  </sect1>

  <sect1 xml:id="network-dhcp">
    <!--
    <sect1info>
      <authorgroup>
	<author>
	  <firstname>Greg</firstname>
	  <surname>Sutter</surname>
	  <contrib>Written by </contrib>
	</author>
      </authorgroup>
    </sect1info>
    -->
    <title>Dynamic Host Configuration Protocol
      (<acronym>DHCP</acronym>)</title>

    <indexterm>
      <primary>Dynamic Host Configuration Protocol</primary>
      <see><acronym>DHCP</acronym></see>
    </indexterm>
    <indexterm>
      <primary>Internet Systems Consortium (ISC)</primary>
    </indexterm>

    <para>The Dynamic Host Configuration Protocol
      (<acronym>DHCP</acronym>) allows a system to connect to a
      network in order to be assigned the necessary addressing
      information for communication on that network.  &os; includes
      the OpenBSD version of <command>dhclient</command> which is used
      by the client to obtain the addressing information.  &os; does
      not install a <acronym>DHCP</acronym> server, but several
      servers are available in the &os; Ports Collection.  The
      <acronym>DHCP</acronym> protocol is fully described in <link
	xlink:href="http://www.freesoft.org/CIE/RFC/2131/">RFC
	2131</link>.
      Informational resources are also available at <link
	xlink:href="http://www.isc.org/downloads/dhcp/">isc.org/downloads/dhcp/</link>.</para>

    <para>This section describes how to use the built-in
      <acronym>DHCP</acronym> client.  It then describes how to
      install and configure a <acronym>DHCP</acronym> server.</para>

    <note>
      <para>In &os;, the &man.bpf.4; device is needed by both the
	<acronym>DHCP</acronym> server and <acronym>DHCP</acronym>
	client.  This device is included in the
	<filename>GENERIC</filename>  kernel that is installed with
	&os;.  Users who prefer to create a custom kernel need to keep
	this device if  <acronym>DHCP</acronym> is used.</para>

      <para>It should be noted that <filename>bpf</filename> also
	allows privileged users to run network packet sniffers on
	that system.</para>
    </note>

    <sect2>
      <title>Configuring a <acronym>DHCP</acronym> Client</title>

      <para><acronym>DHCP</acronym> client support is included in the
	&os; installer, making it easy to configure a newly installed
	system to automatically receive its networking addressing
	information from an existing <acronym>DHCP</acronym> server.
	Refer to <xref linkend="bsdinstall-post"/> for examples of
	network configuration.</para>

      <indexterm><primary><acronym>UDP</acronym></primary></indexterm>
      <para>When <command>dhclient</command> is executed on the client
	machine, it begins broadcasting requests for configuration
	information.  By default, these requests use
	<acronym>UDP</acronym> port 68.  The server replies on
	<acronym>UDP</acronym> port 67, giving the client an
	<acronym>IP</acronym> address and other relevant network
	information such as a subnet mask, default gateway, and
	<acronym>DNS</acronym> server addresses.  This information is
	in the form of a <acronym>DHCP</acronym>
	<quote>lease</quote> and is valid for a configurable time.
	This allows stale <acronym>IP</acronym> addresses for clients
	no longer connected to the network to automatically be reused.
	<acronym>DHCP</acronym> clients can obtain a great deal of
	information from the server.  An exhaustive list may be found
	in &man.dhcp-options.5;.</para>

      <para>By default, when a &os; system boots, its
	<acronym>DHCP</acronym> client runs in the background, or
	<firstterm>asynchronously</firstterm>.  Other startup scripts
	continue to run while the <acronym>DHCP</acronym> process
	completes, which speeds up system startup.</para>

      <para>Background <acronym>DHCP</acronym> works well when the
	<acronym>DHCP</acronym> server responds quickly to the
	client's requests.  However, <acronym>DHCP</acronym> may take
	a long time to complete on some systems.  If network services
	attempt to run before <acronym>DHCP</acronym> has assigned the
	network addressing information, they will fail.  Using
	<acronym>DHCP</acronym> in <firstterm>synchronous</firstterm>
	mode prevents this problem as it pauses startup until the
	<acronym>DHCP</acronym> configuration has completed.</para>

      <para>This line in <filename>/etc/rc.conf</filename> is used to
	configure background or asynchronous mode:</para>

      <programlisting>ifconfig_<replaceable>fxp0</replaceable>="DHCP"</programlisting>

      <para>This line may already exist if the system was configured
	to use <acronym>DHCP</acronym> during installation.  Replace
	the <replaceable>fxp0</replaceable> shown in these examples
	with the name of the interface to be dynamically configured,
	as described in <xref linkend="config-network-setup"/>.</para>

      <para>To instead configure the system to use synchronous mode,
	and to pause during startup while <acronym>DHCP</acronym>
	completes, use
	<quote><literal>SYNCDHCP</literal></quote>:</para>

      <programlisting>ifconfig_<replaceable>fxp0</replaceable>="SYNCDHCP"</programlisting>

      <para>Additional client options are available.  Search for
	<literal>dhclient</literal> in &man.rc.conf.5; for
	details.</para>

      <indexterm>
	<primary><acronym>DHCP</acronym></primary>
	<secondary>configuration files</secondary>
      </indexterm>

      <para>The <acronym>DHCP</acronym> client uses the following
	files:</para>

      <itemizedlist>
	<listitem>
	  <para><filename>/etc/dhclient.conf</filename></para>

	  <para>The configuration file used by
	    <command>dhclient</command>.  Typically, this file
	    contains only comments as the defaults are suitable for
	    most clients.  This configuration file is described in
	    &man.dhclient.conf.5;.</para>
	</listitem>

	<listitem>
	  <para><filename>/sbin/dhclient</filename></para>

	  <para>More information about the command itself can
	    be found in &man.dhclient.8;.</para>
	</listitem>

	<listitem>
	  <para><filename>/sbin/dhclient-script</filename></para>

	  <para>The
	    &os;-specific <acronym>DHCP</acronym> client configuration
	    script.  It is described in &man.dhclient-script.8;, but
	    should not need any user modification to function
	    properly.</para>
	</listitem>

	<listitem>
	  <para><filename>/var/db/dhclient.leases.<replaceable>interface</replaceable></filename></para>

	  <para>The <acronym>DHCP</acronym> client keeps a database of
	    valid leases in this file, which is written as a log and
	    is described in &man.dhclient.leases.5;.</para>
	</listitem>
      </itemizedlist>
    </sect2>

    <sect2 xml:id="network-dhcp-server">
      <title>Installing and Configuring a <acronym>DHCP</acronym>
	Server</title>

      <para>This section demonstrates how to configure a &os; system
	to act as a <acronym>DHCP</acronym> server using the Internet
	Systems Consortium (<acronym>ISC</acronym>) implementation of
	the <acronym>DHCP</acronym> server.  This implementation and
	its documentation can be installed using the
	<package>net/isc-dhcp43-server</package> package or
	port.</para>

      <indexterm>
	<primary><acronym>DHCP</acronym></primary>
	<secondary>server</secondary>
      </indexterm>

      <indexterm>
	<primary><acronym>DHCP</acronym></primary>
	  <secondary>installation</secondary>
      </indexterm>

      <para>The installation of
	<package>net/isc-dhcp43-server</package> installs a sample
	configuration file.  Copy
	<filename>/usr/local/etc/dhcpd.conf.example</filename> to
	<filename>/usr/local/etc/dhcpd.conf</filename> and make any
	edits to this new file.</para>

      <indexterm>
	<primary><acronym>DHCP</acronym></primary>
	  <secondary>dhcpd.conf</secondary>
      </indexterm>
      <para>The configuration file is comprised of declarations for
	subnets and hosts which define the  information that is
	provided to <acronym>DHCP</acronym>  clients.  For example,
	these  lines configure the following:</para>

      <programlisting>option domain-name "example.org";<co xml:id="domain-name"/>
option domain-name-servers ns1.example.org;<co xml:id="domain-name-servers"/>
option subnet-mask 255.255.255.0;<co xml:id="subnet-mask"/>

default-lease-time 600;<co xml:id="default-lease-time"/>
max-lease-time 72400;<co xml:id="max-lease-time"/>
ddns-update-style none;<co xml:id="ddns-update-style"/>

subnet 10.254.239.0 netmask 255.255.255.224 {
  range 10.254.239.10 10.254.239.20;<co xml:id="range"/>
  option routers rtr-239-0-1.example.org, rtr-239-0-2.example.org;<co xml:id="routers"/>
}

host fantasia {
  hardware ethernet 08:00:07:26:c0:a5;<co xml:id="hardware"/>
  fixed-address fantasia.fugue.com;<co xml:id="fixed-address"/>
}</programlisting>

      <calloutlist>
	<callout arearefs="domain-name">
	  <para>This option specifies the default search domain that
	    will be provided to clients.  Refer to
	    &man.resolv.conf.5; for more information.</para>
	</callout>

	<callout arearefs="domain-name-servers">
	  <para>This option specifies a comma separated list of
	    <acronym>DNS</acronym> servers that the client should use.
	    They can be listed by their Fully Qualified Domain Names
	    (<acronym>FQDN</acronym>), as seen in the example, or by
	    their <acronym>IP</acronym> addresses.</para>
	</callout>

	<callout arearefs="subnet-mask">
	  <para>The subnet mask that will be provided to
	    clients.</para>
	</callout>

	<callout arearefs="default-lease-time">
	  <para>The default lease expiry time in seconds.  A client
	    can be configured to override this value.</para>
	</callout>

	<callout arearefs="max-lease-time">
	  <para>The maximum allowed length of time, in seconds, for a
	    lease.  Should a client request a longer lease, a lease
	    will still be issued, but it will only be valid for
	    <literal>max-lease-time</literal>.</para>
	</callout>

	<callout arearefs="ddns-update-style">
	  <para>The default of <option>none</option> disables dynamic
	    DNS updates.  Changing this to <option>interim</option>
	    configures the <acronym>DHCP</acronym> server to update a
	    <acronym>DNS</acronym> server whenever it hands out a
	    lease so that the <acronym>DNS</acronym> server knows
	    which <acronym>IP</acronym> addresses are associated with
	    which computers in the network.  Do not change the default
	    setting unless the <acronym>DNS</acronym> server has  been
	    configured to support dynamic
	    <acronym>DNS</acronym>.</para>
	</callout>

	<callout arearefs="range">
	  <para>This line creates a pool of available
	    <acronym>IP</acronym> addresses which are reserved for
	    allocation to <acronym>DHCP</acronym> clients.  The range
	    of addresses must be valid for the network or subnet
	    specified in the previous line.</para>
	</callout>

	<callout arearefs="routers">
	  <para>Declares the default gateway that is valid for the
	    network or subnet specified before the opening
	    <literal>{</literal> bracket.</para>
	</callout>

	<callout arearefs="hardware">
	  <para>Specifies the hardware <acronym>MAC</acronym> address
	    of a client so that the <acronym>DHCP</acronym> server can
	    recognize the client when it makes a request.</para>
	</callout>

	<callout arearefs="fixed-address">
	  <para>Specifies that this host should always be given the
	    same <acronym>IP</acronym> address.  Using the hostname is
	    correct, since the <acronym>DHCP</acronym> server will
	    resolve the hostname before returning the lease
	    information.</para>
	</callout>
      </calloutlist>

      <para>This configuration file supports many more options.  Refer
	to dhcpd.conf(5), installed with the server, for details and
	examples.</para>

      <para>Once the configuration of <filename>dhcpd.conf</filename>
	is complete, enable the <acronym>DHCP</acronym> server in
	<filename>/etc/rc.conf</filename>:</para>

      <programlisting>dhcpd_enable="YES"
dhcpd_ifaces="dc0"</programlisting>

      <para>Replace the <literal>dc0</literal> with the interface (or
	interfaces, separated by whitespace) that the
	<acronym>DHCP</acronym> server should listen on for
	<acronym>DHCP</acronym> client requests.</para>

      <para>Start the server by issuing the following command:</para>

      <screen>&prompt.root; <userinput>service isc-dhcpd start</userinput></screen>

      <para>Any future changes to the configuration of the server will
	require the <application>dhcpd</application> service to be
	stopped and then started using &man.service.8;.</para>

      <para>The <acronym>DHCP</acronym> server uses the following
	files.  Note that the manual pages are installed with the
	server software.</para>

      <indexterm>
	<primary><acronym>DHCP</acronym></primary>
	<secondary>configuration files</secondary>
      </indexterm>
      <itemizedlist>
	<listitem>
	  <para><filename>/usr/local/sbin/dhcpd</filename></para>

	  <para>More information about the
	    <application>dhcpd</application> server can be found in
	    dhcpd(8).</para>
	</listitem>

	<listitem>
	  <para><filename>/usr/local/etc/dhcpd.conf</filename></para>

	  <para>The server configuration file needs to contain all the
	    information that should be provided to clients, along with
	    information regarding the operation of the server.  This
	    configuration file is described in dhcpd.conf(5).</para>
	</listitem>

	<listitem>
	  <para><filename>/var/db/dhcpd.leases</filename></para>

	  <para>The <acronym>DHCP</acronym> server keeps a database of
	    leases it has issued in this file, which is written as a
	    log.  Refer to dhcpd.leases(5), which gives a slightly
	    longer description.</para>
	</listitem>

	<listitem>
	  <para><filename>/usr/local/sbin/dhcrelay</filename></para>

	  <para>This daemon is used in advanced environments where one
	    <acronym>DHCP</acronym> server forwards a request from a
	    client to another <acronym>DHCP</acronym> server on a
	    separate network.  If this functionality is required,
	    install the <package>net/isc-dhcp43-relay</package>
	    package or port.  The installation includes dhcrelay(8)
	    which provides more detail.</para>
	</listitem>
      </itemizedlist>
    </sect2>
  </sect1>

  <sect1 xml:id="network-dns">
    <!--
    <sect1info>
      <authorgroup>
	<author>
	  <firstname>Chern</firstname>
	  <surname>Lee</surname>
	  <contrib>Contributed by </contrib>
	</author>

	<author>
	  <firstname>Tom</firstname>
	  <surname>Rhodes</surname>
	</author>

	<author>
	  <firstname>Daniel</firstname>
	  <surname>Gerzo</surname>
	</author>
      </authorgroup>
    </sect1info>
    -->
    <title>Domain Name System (<acronym>DNS</acronym>)</title>

    <indexterm><primary>DNS</primary></indexterm>

    <para>Domain Name System (<acronym>DNS</acronym>) is the protocol
      through which domain names are mapped to <acronym>IP</acronym>
      addresses, and vice versa.  <acronym>DNS</acronym> is
      coordinated across the Internet through a somewhat complex
      system of authoritative root, Top Level Domain
      (<acronym>TLD</acronym>), and other smaller-scale name servers,
      which host and cache individual domain information.  It is not
      necessary to run a name server to perform
      <acronym>DNS</acronym> lookups on a system.</para>

    <indexterm><primary>resolver</primary></indexterm>
    <indexterm><primary>reverse
      <acronym>DNS</acronym></primary></indexterm>
    <indexterm><primary>root zone</primary></indexterm>

    <para>The following table describes some of the terms associated
      with <acronym>DNS</acronym>:</para>

    <table frame="none" pgwide="1">
      <title><acronym>DNS</acronym> Terminology</title>

      <tgroup cols="2">
	<colspec colwidth="1*"/>
	<colspec colwidth="3*"/>

	<thead>
	  <row>
	    <entry>Term</entry>
	    <entry>Definition</entry>
	  </row>
	</thead>

	<tbody>
	  <row>
	    <entry>Forward <acronym>DNS</acronym></entry>
	    <entry>Mapping of hostnames to <acronym>IP</acronym>
	      addresses.</entry>
	  </row>

	  <row>
	    <entry>Origin</entry>
	    <entry>Refers to the domain covered in a particular zone
	      file.</entry>
	  </row>

	  <row>
	    <entry>Resolver</entry>
	    <entry>A system process through which a machine queries
	      a name server for zone information.</entry>
	  </row>

	  <row>
	    <entry>Reverse <acronym>DNS</acronym></entry>
	    <entry>Mapping of <acronym>IP</acronym> addresses to
	      hostnames.</entry>
	  </row>

	  <row>
	    <entry>Root zone</entry>

	    <entry>The beginning of the Internet zone hierarchy.  All
	      zones fall under the root zone, similar to how all files
	      in a file system fall under the root directory.</entry>
	  </row>

	  <row>
	    <entry>Zone</entry>
	    <entry>An individual domain, subdomain, or portion of the
	      <acronym>DNS</acronym> administered by the same
	      authority.</entry>
	  </row>
	</tbody>
      </tgroup>
    </table>

    <indexterm>
      <primary>zones</primary>
      <secondary>examples</secondary>
    </indexterm>

    <para>Examples of zones:</para>

    <itemizedlist>
      <listitem>
	<para><systemitem>.</systemitem> is how the root zone is
	  usually referred to in documentation.</para>
      </listitem>

      <listitem>
	<para><systemitem>org.</systemitem> is a Top Level Domain
	  (<acronym>TLD</acronym>) under the root zone.</para>
      </listitem>

      <listitem>
	<para><systemitem
	    class="fqdomainname">example.org.</systemitem> is a zone
	  under the <systemitem>org.</systemitem>
	  <acronym>TLD</acronym>.</para>
      </listitem>

      <listitem>
	<para><systemitem>1.168.192.in-addr.arpa</systemitem> is a
	  zone referencing all <acronym>IP</acronym> addresses which
	  fall under the <systemitem
	      class="ipaddress">192.168.1.*</systemitem>
	  <acronym>IP</acronym> address space.</para>
      </listitem>
    </itemizedlist>

    <para>As one can see, the more specific part of a hostname
      appears to its left.  For example, <systemitem
	class="fqdomainname">example.org.</systemitem> is more
      specific than <systemitem>org.</systemitem>, as
      <systemitem>org.</systemitem> is more specific than the root
      zone.  The layout of each part of a hostname is much like a file
      system: the <filename>/dev</filename> directory falls within the
      root, and so on.</para>

    <sect2>
      <title>Reasons to Run a Name Server</title>

      <para>Name servers generally come in two forms: authoritative
	name servers, and caching (also known as resolving) name
	servers.</para>

      <para>An authoritative name server is needed when:</para>

      <itemizedlist>
	<listitem>
	  <para>One wants to serve <acronym>DNS</acronym> information
	    to the world, replying authoritatively to queries.</para>
	</listitem>

	<listitem>
	  <para>A domain, such as <systemitem
	      class="fqdomainname">example.org</systemitem>, is
	    registered and <acronym>IP</acronym> addresses need to be
	    assigned to hostnames under it.</para>
	</listitem>

	<listitem>
	  <para>An <acronym>IP</acronym> address block requires
	    reverse <acronym>DNS</acronym> entries
	    (<acronym>IP</acronym> to hostname).</para>
	</listitem>

	<listitem>
	  <para>A backup or second name server, called a slave, will
	    reply to queries.</para>
	</listitem>
      </itemizedlist>

      <para>A caching name server is needed when:</para>

      <itemizedlist>
	<listitem>
	  <para>A local <acronym>DNS</acronym> server may cache and
	    respond more quickly than querying an outside name
	    server.</para>
	</listitem>
      </itemizedlist>

      <para>When one queries for <systemitem
	  class="fqdomainname">www.FreeBSD.org</systemitem>, the
	resolver usually queries the uplink <acronym>ISP</acronym>'s
	name server, and retrieves the reply.  With a local, caching
	<acronym>DNS</acronym> server, the query only has to be made
	once to the outside world by the caching
	<acronym>DNS</acronym> server.  Additional queries will not
	have to go outside the local network, since the information is
	cached locally.</para>
    </sect2>

    <sect2>
      <title><acronym>DNS</acronym> Server Configuration</title>

      <para><application>Unbound</application> is provided in the &os;
	base system.  By default, it will provide
	<acronym>DNS</acronym> resolution to the local machine only.
	While the base system package can be configured to provide
	resolution services beyond the local machine, it is
	recommended that such requirements be addressed by installing
	<application>Unbound</application> from the &os; Ports
	Collection.</para>

      <para>To enable <application>Unbound</application>, add the
	following to <filename>/etc/rc.conf</filename>:</para>

      <programlisting>local_unbound_enable="YES"</programlisting>

      <para>Any existing nameservers in
	<filename>/etc/resolv.conf</filename> will be configured as
	forwarders in the new <application>Unbound</application>
	configuration.</para>

      <note>
	<para>If any of the listed nameservers do not support
	  <acronym>DNSSEC</acronym>, local <acronym>DNS</acronym>
	  resolution will fail.  Be sure to test each nameserver and
	  remove any that fail the test.  The following command will
	  show the trust tree or a failure for a nameserver running on
	  <systemitem
	    class="ipaddress">192.168.1.1</systemitem>:</para>
      </note>

      <screen>&prompt.user; <userinput>drill -S FreeBSD.org @<replaceable>192.168.1.1</replaceable></userinput></screen>

      <para>Once each nameserver is confirmed to support
	<acronym>DNSSEC</acronym>, start
	<application>Unbound</application>:</para>

      <screen>&prompt.root; <userinput>service local_unbound onestart</userinput></screen>

      <para>This will take care of updating
	<filename>/etc/resolv.conf</filename> so that queries for
	<acronym>DNSSEC</acronym> secured domains will now work.  For
	example, run the following to validate the FreeBSD.org
	<acronym>DNSSEC</acronym> trust tree:</para>

      <screen>&prompt.user; <userinput>drill -S FreeBSD.org</userinput>
;; Number of trusted keys: 1
;; Chasing: freebsd.org. A

DNSSEC Trust tree:
freebsd.org. (A)
|---freebsd.org. (DNSKEY keytag: 36786 alg: 8 flags: 256)
    |---freebsd.org. (DNSKEY keytag: 32659 alg: 8 flags: 257)
    |---freebsd.org. (DS keytag: 32659 digest type: 2)
        |---org. (DNSKEY keytag: 49587 alg: 7 flags: 256)
            |---org. (DNSKEY keytag: 9795 alg: 7 flags: 257)
            |---org. (DNSKEY keytag: 21366 alg: 7 flags: 257)
            |---org. (DS keytag: 21366 digest type: 1)
            |   |---. (DNSKEY keytag: 40926 alg: 8 flags: 256)
            |       |---. (DNSKEY keytag: 19036 alg: 8 flags: 257)
            |---org. (DS keytag: 21366 digest type: 2)
                |---. (DNSKEY keytag: 40926 alg: 8 flags: 256)
                    |---. (DNSKEY keytag: 19036 alg: 8 flags: 257)
;; Chase successful</screen>
    </sect2>
  </sect1>

  <sect1 xml:id="network-apache">
    <info>
      <title>Apache HTTP Server</title>

      <authorgroup>
	<author>
	  <personname>
	    <firstname>Murray</firstname>
	    <surname>Stokely</surname>
	  </personname>
	  <contrib>Contributed by </contrib>
	</author>
      </authorgroup>
    </info>

    <indexterm><primary>web servers</primary>
      <secondary>setting up</secondary></indexterm>
    <indexterm><primary>Apache</primary></indexterm>

    <para>The open source
      <application>Apache HTTP Server</application> is the most widely
      used web server.  &os; does not install this web server by
      default, but it can be installed from the
      <package>www/apache24</package> package or port.</para>

    <para>This section summarizes how to configure and start version
      2.<replaceable>x</replaceable> of the <application>Apache HTTP
	Server</application> on &os;.  For more detailed information
      about <application>Apache</application>&nbsp;2.X and its
      configuration directives, refer to <link
	xlink:href="http://httpd.apache.org/">httpd.apache.org</link>.</para>

    <sect2>
      <title>Configuring and Starting Apache</title>

      <indexterm><primary>Apache</primary>
	<secondary>configuration file</secondary></indexterm>

      <para>In &os;, the main <application>Apache HTTP
	  Server</application> configuration file is installed as
	<filename>/usr/local/etc/apache2<replaceable>x</replaceable>/httpd.conf</filename>,
	where <replaceable>x</replaceable> represents the version
	number.  This <acronym>ASCII</acronym> text file begins
	comment lines with a <literal>#</literal>.  The most
	frequently modified directives are:</para>

      <variablelist>
	<varlistentry>
	  <term><literal>ServerRoot "/usr/local"</literal></term>

	  <listitem>
	    <para>Specifies the default directory hierarchy for the
	      <application>Apache</application> installation.
	      Binaries are stored in the <filename>bin</filename> and
	      <filename>sbin</filename> subdirectories of the server
	      root and configuration files are stored in the <filename
		>etc/apache2<replaceable>x</replaceable></filename>
	      subdirectory.</para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term><literal>ServerAdmin you@example.com</literal></term>

	  <listitem>
	    <para>Change this to the email address to receive problems
	      with the server.  This address also appears on some
	      server-generated pages, such as error documents.</para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term><literal>ServerName
	      www.example.com:80</literal></term>

	  <listitem>
	    <para>Allows an administrator to set a hostname which is
	      sent back to clients for the server.  For example,
	      <systemitem>www</systemitem> can be used instead of the
	      actual hostname.  If the system does not have a
	      registered <acronym>DNS</acronym> name, enter its
	      <acronym>IP</acronym> address instead.  If the server
	      will listen on an alternate report, change
	      <literal>80</literal> to the alternate port
	      number.</para>
	  </listitem>
	</varlistentry>

	<varlistentry>
	  <term><literal>DocumentRoot
	    "/usr/local/www/apache2<replaceable>x</replaceable>/data"</literal></term>

	  <listitem>
	    <para>The directory where documents will be served from.
	      By default, all requests are taken from this directory,
	      but symbolic links and aliases may be used to point to
	      other locations.</para>
	  </listitem>
	</varlistentry>
      </variablelist>

      <para>It is always a good idea to make a backup copy of the
	default <application>Apache</application> configuration file
	before making changes.  When the configuration of
	<application>Apache</application> is complete, save the file
	and verify the configuration using
	<command>apachectl</command>.  Running <command>apachectl
	  configtest</command> should return <literal>Syntax
	  OK</literal>.</para>

      <indexterm><primary>Apache</primary>
	<secondary>starting or stopping</secondary></indexterm>

      <para>To launch <application>Apache</application> at system
	startup, add the following line to
	<filename>/etc/rc.conf</filename>:</para>

      <programlisting>apache<replaceable>24</replaceable>_enable="YES"</programlisting>

      <para>If <application>Apache</application> should be started
	with non-default options, the following line may be added to
	<filename>/etc/rc.conf</filename> to specify the needed
	flags:</para>

      <programlisting>apache<replaceable>24</replaceable>_flags=""</programlisting>

      <para>If <application>apachectl</application> does not report
	configuration errors, start <command>httpd</command>
	now:</para>

      <screen>&prompt.root; <userinput>service apache<replaceable>24</replaceable> start</userinput></screen>

      <para>The <command>httpd</command> service can be tested by
	entering
	<literal>http://<replaceable>localhost</replaceable></literal>
	in a web browser, replacing
	<replaceable>localhost</replaceable> with the fully-qualified
	domain name of the machine running <command>httpd</command>.
	The default web page that is displayed is
	<filename>/usr/local/www/apache<replaceable>24</replaceable>/data/index.html</filename>.</para>

      <para>The <application>Apache</application> configuration can be
	tested for errors after making subsequent configuration
	changes while <command>httpd</command> is running using the
	following command:</para>

      <screen>&prompt.root; <userinput>service apache<replaceable>24</replaceable> configtest</userinput></screen>

      <note>
	<para>It is important to note that
	  <literal>configtest</literal> is not an &man.rc.8; standard,
	  and should not be expected to work for all startup
	  scripts.</para>
      </note>
    </sect2>

    <sect2>
      <title>Virtual Hosting</title>

      <para>Virtual hosting allows multiple websites to run on one
	<application>Apache</application> server.  The virtual hosts
	can be <firstterm>IP-based</firstterm> or
	<firstterm>name-based</firstterm>.
	<acronym>IP</acronym>-based virtual hosting uses a different
	<acronym>IP</acronym> address for each website.  Name-based
	virtual hosting uses the clients HTTP/1.1 headers to figure
	out the hostname, which allows the websites to share the same
	<acronym>IP</acronym> address.</para>

      <para>To setup <application>Apache</application> to use
	name-based virtual hosting, add a
	<literal>VirtualHost</literal> block for each website.  For
	example, for the webserver named <systemitem
	  class="fqdomainname">www.domain.tld</systemitem> with a
	virtual domain of <systemitem
	  class="fqdomainname">www.someotherdomain.tld</systemitem>,
	add the following entries to
	<filename>httpd.conf</filename>:</para>

      <programlisting>&lt;VirtualHost *&gt;
    ServerName <replaceable>www.domain.tld</replaceable>
    DocumentRoot <replaceable>/www/domain.tld</replaceable>
&lt;/VirtualHost&gt;

&lt;VirtualHost *&gt;
    ServerName <replaceable>www.someotherdomain.tld</replaceable>
    DocumentRoot <replaceable>/www/someotherdomain.tld</replaceable>
&lt;/VirtualHost&gt;</programlisting>

      <para>For each virtual host, replace the values for
	<literal>ServerName</literal> and
	<literal>DocumentRoot</literal> with the values to be
	used.</para>

      <para>For more information about setting up virtual hosts,
	consult the official <application>Apache</application>
	documentation at: <uri
	  xlink:href="http://httpd.apache.org/docs/vhosts/">http://httpd.apache.org/docs/vhosts/</uri>.</para>
    </sect2>

    <sect2>
      <title>Apache Modules</title>

      <indexterm><primary>Apache</primary>
	<secondary>modules</secondary></indexterm>

      <para><application>Apache</application> uses modules to augment
	the functionality provided by the basic server.  Refer to <uri
	  xlink:href="http://httpd.apache.org/docs/current/mod/">http://httpd.apache.org/docs/current/mod/</uri>
	for a complete listing of and the configuration details for
	the available modules.</para>

      <para>In &os;, some modules can be compiled with the
	<package>www/apache24</package> port.  Type <command>make
	  config</command> within
	<filename>/usr/ports/www/apache24</filename> to see which
	modules are available and which are enabled by default.  If
	the module is not compiled with the port, the &os; Ports
	Collection provides an easy way to install many modules.  This
	section describes three of the most commonly used
	modules.</para>

      <sect3>
	<title>SSL support</title>

	<indexterm>
	  <primary>web servers</primary>
	  <secondary>secure</secondary>
	</indexterm>
	<indexterm><primary>SSL</primary></indexterm>
	<indexterm><primary>cryptography</primary></indexterm>

	<para>At one in point in time, support for <acronym>SSL</acronym>
	  inside of Apache required a secondary module called
	  <filename>mod_ssl</filename>. This is no longer the case and
	  the default install of Apache comes with <acronym>SSL</acronym>
	  built into the web server. An example of how to enable
	  support for <acronym>SSL</acronym> websites is available
	  in the installed file, <filename>httpd-ssl.conf</filename>
	  inside of the
	  <filename role="directory">/usr/local/etc/apache24/extra</filename>
	  directory. Inside this directory is also a sample file called
	  named <filename>ssl.conf-sample</filename>. It is recommended
	  that both files be evaluated to properly set up secure websites
	  in the Apache web server.</para>

	<para>After the configuration of <acronym>SSL</acronym> is
	  complete, the following line must be uncommented in the main
	  <filename>http.conf</filename> to activate the changes on the
	  next restart or reload of Apache:</para>

	<programlisting>#Include etc/apache24/extra/httpd-ssl.conf</programlisting>

	<warning>
	  <para><acronym>SSL</acronym> version two and version three have
	    known vulnerability issues. It is highly recommended TLS version 
	    1.2 and 1.3 be enabled in place of the older SSL options.
	    This can be accomplished by setting the following options in the
	    <filename>ssl.conf</filename>:</para>
	</warning>

	<programlisting>SSLProtocol all -SSLv3 -SSLv2 +TLSv1.2 +TLSv1.3
SSLProxyProtocol all -SSLv2 -SSLv3 -TLSv1 -TLSv1.1</programlisting>

	<para>To complete the configuration of <acronym>SSL</acronym>
	  in the web server, uncomment the following line to ensure that
	  the configuration will be pulled into Apache during restart or
	  reload:</para>

	<programlisting># Secure (SSL/TLS) connections
Include etc/apache24/extra/httpd-ssl.conf</programlisting>

	<para>The following lines must also be uncommented in the
	  <filename>httpd.conf</filename> to fully support
	  <acronym>SSL</acronym> in Apache:</para>

	<programlisting>LoadModule authn_socache_module libexec/apache24/mod_authn_socache.so
LoadModule socache_shmcb_module libexec/apache24/mod_socache_shmcb.so
LoadModule ssl_module libexec/apache24/mod_ssl.so</programlisting>

	<para>The next step is to work with a certificate authority
	  to have the appropriate certificates installed on the
	  system. This will set up a chain of trust for the site
	  and prevent any warnings of self-signed certificates.</para>

      </sect3>

      <sect3>
	<title><filename>mod_perl</filename></title>

	<indexterm>
	  <primary>mod_perl</primary>
	  <secondary>Perl</secondary>
	</indexterm>

	<para>The
	  <filename>mod_perl</filename> module makes it possible to
	  write <application>Apache</application> modules in
	  <application>Perl</application>.  In addition, the
	  persistent interpreter embedded in the server avoids the
	  overhead of starting an external interpreter and the penalty
	  of <application>Perl</application> start-up time.</para>

	<para>The <filename>mod_perl</filename> can be installed using
	  the <package>www/mod_perl2</package> package or port.
	  Documentation for using this module can be found at <uri
	    xlink:href="http://perl.apache.org/docs/2.0/index.html">http://perl.apache.org/docs/2.0/index.html</uri>.</para>
      </sect3>

      <sect3>
	<info>
	  <title><filename>mod_php</filename></title>

	  <authorgroup>
	    <author>
	      <personname>
		<firstname>Tom</firstname>
		<surname>Rhodes</surname>
	      </personname>
	      <contrib>Written by </contrib>
	    </author>
	  </authorgroup>
	</info>

	<indexterm>
	  <primary>mod_php</primary>
	  <secondary>PHP</secondary>
	</indexterm>

	<para><firstterm>PHP: Hypertext Preprocessor</firstterm>
	  (<acronym>PHP</acronym>) is a general-purpose scripting
	  language that is especially suited for web development.
	  Capable of being embedded into <acronym>HTML</acronym>, its
	  syntax draws upon <application>C</application>, &java;, and
	  <application>Perl</application> with the intention of
	  allowing web developers to write dynamically generated
	  webpages quickly.</para>

	<para>Support for <acronym>PHP</acronym> for
	  <application>Apache</application> and any other feature
	  written in the language, can be added
	  by installing the appropriate port.</para>

	<para>For all supported versions, search the package database
	  using <command>pkg</command>. Here is an example of the
	  available <acronym>PHP</acronym> packages as of the time
	  of this writing:</para>

	<screen>&prompt.root; <userinput>pkg search php</userinput></screen>

	<para>A list will be displayed including the versions and
	  additional features they provide. The components are
	  completely modular, meaning features are enabled by
	  installing the appropriate port. To install
	  <acronym>PHP</acronym> version 7.4 for Apache, issue
	  the following command:</para>

	<screen>&prompt.root; <userinput>pkg install mod_php74</userinput></screen>

	<para>If any dependency packages need to be installed, they will
	  be installed as well.</para>

	<para>By default, <acronym>PHP</acronym> will not be
	  enabled. The following lines will need to be added to
	  the Apache configuration file located in
	  <filename role="directory">/usr/local/etc/apache24</filename>
	  to make it active:</para>

	<programlisting>&lt;FilesMatch "\.php$"&gt;
    SetHandler application/x-httpd-php
&lt;/FilesMatch&gt;
&lt;FilesMatch "\.phps$"&gt;
    SetHandler application/x-httpd-php-source
&lt;/FilesMatch&gt;</programlisting>

	<para>In addition, the <option>DirectoryIndex</option> in
	  the configuration file will also need to be updated
	  and Apache will either need to be restarted or reloaded
	  for the changes to take effect.</para>

	<para>Support for many of the <acronym>PHP</acronym>
	  features may also be installed by using
	  <command>pkg</command>. For example, to install
	  support for <acronym>XML</acronym> or
	  <acronym>SSL</acronym>, install their respective
	  ports:</para>

	<screen>&prompt.root; <userinput>pkg install php74-xml php74-openssl</userinput></screen>

	<para>As before, the Apache configuration will need to be
	  reloaded for the changes to take effect, even in cases
	  where it was just a module install.</para>

	<para>To perform a graceful restart to reload the
	  configuration, issue the following command:</para>

	<screen>&prompt.root; <userinput>apachectl graceful</userinput></screen>

	<para>Once the install is complete, there are two methods of
	  obtaining the installed <acronym>PHP</acronym> support modules
	  and the environmental information of the build. The first is
	  to install the full <acronym>PHP</acronym> binary and running
	  the command to gain the information:</para>

	<screen>&prompt.root; <userinput>pkg install php74</userinput></screen>
	<screen>&prompt.root; <userinput>php -i |less</userinput></screen>

	<para>It is necessary to pass the output to a pager, such as
	  the <command>more</command> or <command>less</command> to
	  easier digest the amount of output.</para>

	<para>Finally, to make any changes to the global configuration
	  of <acronym>PHP</acronym> there is a well documented file
	  installed into
	  <filename role="directory">/usr/local/etc/php.ini</filename>.
	  At the time of install, this file will not exist because there
	  are two versions to choose from, one is
	  <filename>php.ini-development</filename> and the other is
	  <filename>php.ini-production</filename>. These are starting
	  points to assist administrators in their deployment.</para>
      </sect3>

      <sect3>
	<info>
	  <title>HTTP2 Support</title>
	</info>

	<para><application>Apache</application> support for
	  the <acronym>HTTP</acronym>2 protocol is included by default
	  when installing the port with <command>pkg</command>. The new
	  version of <acronym>HTTP</acronym> includes many improvements
	  over the previous version, including utilizing a single
	  connection to a website, reducing overall roundtrips of
	  <acronym>TCP</acronym> connections. Also, packet header data
	  is compressed and <acronym>HTTP</acronym>2 requires
	  encryption by default.</para>

	<para>When <application>Apache</application> is configured to
	  only use <acronym>HTTP</acronym>2, web browsers will
	  require secure, encrypted <acronym>HTTPS</acronym>
	  connections. When <application>Apache</application> is
	  configured to use both versions, <acronym>HTTP</acronym>1.1
	  will be considered a fall back option if any issues
	  arise during the connection.</para>

	<para>While this change does require administrators to make
	  changes, they are positive and equate to a more secure
	  Internet for everyone. The changes are only required for
	  sites not currently implementing <acronym>SSL</acronym>
	  and <acronym>TLS</acronym>.</para>

	<note>
	  <para>This configuration depends on the previous sections,
	    including <acronym>TLS</acronym> support. It is
	    recommended those instructions be followed before
	    continuing with this configuration.</para>
	</note>

	<para>Start the process by enabling the
	  <acronym>http</acronym>2 module by uncommenting the line in
	  <filename>/usr/local/etc/apache24/httpd.conf</filename> and
	  replace the mpm_prefork module with mpm_event as the former
	  does not support <acronym>HTTP</acronym>2.</para>

	<programlisting>LoadModule http2_module libexec/apache24/mod_http2.so
LoadModule mpm_event_module libexec/apache24/mod_mpm_event.so</programlisting>

	<note>
	  <para>There is a separate
	    <filename role="port">mod_http2</filename> port that is
	    available. It exists to deliver security and bug fixes
	    quicker than the module installed with the bundled
	    <filename role="port">apache24</filename> port. It is
	    not required for <acronym>HTTP</acronym>2 support but
	    is available. When installed, the
	    <filename>mod_h2.so</filename> should be used in place
	    of <filename>mod_http2.so</filename> in the
	    <application>Apache</application> configuration.</para>
	</note>

	<para>There are two methods to implement <acronym>HTTP</acronym>2
	  in <application>Apache</application>; one way is globally for
	  all sites and each VirtualHost running on the system. To enable
	  <acronym>HTTP</acronym>2 globally, add the following line
	  under the ServerName directive:</para>

	<programlisting>Protocols h2 http/1.1</programlisting>

	<note>
	  <para>To enable <acronym>HTTP</acronym>2 over plaintext,
	    use <acronym>h2</acronym> <acronym>h2c</acronym>
	    <acronym>http</acronym>/1.1 in the
	    <filename>httpd.conf</filename>.</para>
	</note>

	<para>Having the <acronym>h2c</acronym> here will allow
	  plaintext <acronym>HTTP</acronym>2 data to pass on the
	  system but is not recommended. In addition, using the
	  <acronym>http</acronym>/1.1 here will allow fallback
	  to the <acronym>HTTP</acronym>1.1 version of the protocol
	  should it be needed by the system.</para>

	<para>To enable <acronym>HTTP</acronym>2 for individual
	  VirtualHosts, add the same line within the VirtualHost
	  directive in either <filename>httpd.conf</filename> or
	  <filename>httpd-ssl.conf</filename>.</para>

	<para>Reload the configuration using the
	  <command>apachectl</command> <parameter>reload</parameter> command
	  and test the configuration either by using either of the
	  following methods after visiting one of the hosted pages:</para>

	<screen>&prompt.root; <userinput>grep "HTTP/2.0" /var/log/httpd-access.log</userinput></screen>

	<para>This should return something similar to the following:</para>

	<programlisting>192.168.1.205 - - [18/Oct/2020:18:34:36 -0400] "GET / HTTP/2.0" 304 -
192.0.2.205 - - [18/Oct/2020:19:19:57 -0400] "GET / HTTP/2.0" 304 -
192.0.0.205 - - [18/Oct/2020:19:20:52 -0400] "GET / HTTP/2.0" 304 -
192.0.2.205 - - [18/Oct/2020:19:23:10 -0400] "GET / HTTP/2.0" 304 -</programlisting>

	<para>The other method is using the web browser's built
	  in site debugger or <command>tcpdump</command>; however,
	  using either method is beyond the scope of this
	  document.</para>

	<para>Support for <acronym>HTTP</acronym>2 reverse
	  proxy connections by using the
	  <filename>mod_proxy_http2.so</filename> module. When
	  configuring the ProxyPass or RewriteRules [P] statements,
	  they should use h2:// for the connection.</para>
      </sect3>


    </sect2>

    <sect2>
      <title>Dynamic Websites</title>

      <indexterm>
	<primary>web servers</primary>
	<secondary>dynamic</secondary>
      </indexterm>

      <para>In addition to <application>mod_perl</application> and
	<application>mod_php</application>, other languages are
	available for creating dynamic web content.  These include
	<application>Django</application> and
	<application>Ruby on Rails</application>.</para>

      <sect3>
	<title>Django</title>

	<indexterm><primary>Python</primary></indexterm>
	<indexterm><primary>Django</primary></indexterm>

	<para><application>Django</application> is a BSD-licensed
	  framework designed to allow developers to write high
	  performance, elegant web applications quickly.  It provides
	  an object-relational mapper so that data types are developed
	  as <application>Python</application> objects.  A rich
	  dynamic database-access <acronym>API</acronym> is provided
	  for those objects without the developer ever having to write
	  <acronym>SQL</acronym>.  It also provides an extensible
	  template system so that the logic of the application is
	  separated from the <acronym>HTML</acronym>
	  presentation.</para>

	<para>Django depends on <filename>mod_python</filename>, and
	  an <acronym>SQL</acronym> database engine.  In &os;, the
	  <package>www/py-django</package> port automatically installs
	  <filename>mod_python</filename> and supports the
	  <application>PostgreSQL</application>,
	  <application>MySQL</application>, or
	  <application>SQLite</application> databases, with the
	  default being <application>SQLite</application>.  To change
	  the database engine, type <command>make config</command>
	  within <filename>/usr/ports/www/py-django</filename>, then
	  install the port.</para>

	<para>Once <application>Django</application> is installed, the
	  application will need a project directory along with the
	  <application>Apache</application> configuration in order to
	  use the embedded <application>Python</application>
	  interpreter.  This interpreter is used to call the
	  application for specific <acronym>URL</acronym>s on the
	  site.</para>

	<para>To configure <application>Apache</application> to pass
	  requests for certain <acronym>URL</acronym>s to the web
	  application, add the following to
	  <filename>httpd.conf</filename>, specifying the full path to
	  the project directory:</para>

	<programlisting>&lt;Location "/"&gt;
    SetHandler python-program
    PythonPath "['<replaceable>/dir/to/the/django/packages/</replaceable>'] + sys.path"
    PythonHandler django.core.handlers.modpython
    SetEnv DJANGO_SETTINGS_MODULE mysite.settings
    PythonAutoReload On
    PythonDebug On
&lt;/Location&gt;</programlisting>

	<para>Refer to <uri
	    xlink:href="https://docs.djangoproject.com">https://docs.djangoproject.com</uri>
	  for more information on how to use
	  <application>Django</application>.</para>
      </sect3>

      <sect3>
	<title>Ruby on Rails</title>

	<indexterm><primary>Ruby on Rails</primary></indexterm>

	<para><application>Ruby on Rails</application> is another open
	  source web framework that provides a full development stack.
	  It is optimized to make web developers more productive and
	  capable of writing powerful applications quickly.  On &os;,
	  it can be installed using the
	  <package>www/rubygem-rails</package> package or port.</para>

	<para>Refer to <uri
	    xlink:href="http://guides.rubyonrails.org">http://guides.rubyonrails.org</uri>
	  for more information on how to use <application>Ruby on
	    Rails</application>.</para>
      </sect3>
    </sect2>
  </sect1>

  <sect1 xml:id="network-ftp">
    <!--
    <sect1info>
      <authorgroup>
	<author>
	  <firstname>Murray</firstname>
	  <surname>Stokely</surname>
	  <contrib>Contributed by </contrib>
	</author>
      </authorgroup>
    </sect1info>
    -->
    <title>File Transfer Protocol (<acronym>FTP</acronym>)</title>

    <indexterm><primary><acronym>FTP</acronym>
	servers</primary></indexterm>

    <para>The File Transfer Protocol (<acronym>FTP</acronym>) provides
      users with a simple way to transfer files to and from an
      <acronym>FTP</acronym> server.  &os; includes
      <acronym>FTP</acronym> server software,
      <application>ftpd</application>, in the base system.</para>

    <para>&os; provides several configuration files for controlling
      access to the <acronym>FTP</acronym> server.  This section
      summarizes these files.  Refer to &man.ftpd.8; for more details
      about the built-in <acronym>FTP</acronym> server.</para>

    <sect2>
      <title>Configuration</title>

      <para>The most important configuration step is deciding which
	accounts will be allowed access to the <acronym>FTP</acronym>
	server.  A &os; system has a number of system accounts which
	should not be allowed <acronym>FTP</acronym> access.  The list
	of users disallowed any <acronym>FTP</acronym> access can be
	found in <filename>/etc/ftpusers</filename>.  By default, it
	includes system accounts.  Additional users that should not be
	allowed access to <acronym>FTP</acronym> can be added.</para>

      <para>In some cases it may be desirable to restrict the access
	of some users without preventing them completely from using
	<acronym>FTP</acronym>.  This can be accomplished be creating
	<filename>/etc/ftpchroot</filename> as described in
	&man.ftpchroot.5;.  This file lists users and groups subject
	to <acronym>FTP</acronym> access restrictions.</para>

      <indexterm>
	<primary><acronym>FTP</acronym></primary>
	<secondary>anonymous</secondary>
      </indexterm>

      <para>To enable anonymous <acronym>FTP</acronym> access to the
	server, create a user named <systemitem
	  class="username">ftp</systemitem> on the &os; system.  Users
	will then be able to log on to the
	<acronym>FTP</acronym> server with a username of
	<systemitem class="username">ftp</systemitem> or <systemitem
	  class="username">anonymous</systemitem>.  When prompted for
	the password, any input will be accepted, but by convention,
	an email address should be used as the password.  The
	<acronym>FTP</acronym> server will call &man.chroot.2; when an
	anonymous user logs in, to restrict access to only the home
	directory of the <systemitem
	  class="username">ftp</systemitem> user.</para>

      <para>There are two text files that can be created to specify
	welcome messages to be displayed to <acronym>FTP</acronym>
	clients.  The contents of
	<filename>/etc/ftpwelcome</filename> will be displayed to
	users before they reach the login prompt.  After a successful
	login, the contents of
	<filename>/etc/ftpmotd</filename> will be displayed.  Note
	that the path to this file is relative to the login
	environment, so the contents of
	<filename>~ftp/etc/ftpmotd</filename> would be displayed for
	anonymous users.</para>

      <para>Once the <acronym>FTP</acronym> server has been
	configured, set the appropriate variable in
	<filename>/etc/rc.conf</filename> to start the service during
	boot:</para>

      <programlisting>ftpd_enable="YES"</programlisting>

      <para>To start the service now:</para>

      <screen>&prompt.root; <userinput>service ftpd start</userinput></screen>

      <para>Test the connection to the <acronym>FTP</acronym> server
	by typing:</para>

      <screen>&prompt.user; <userinput>ftp localhost</userinput></screen>

      <indexterm><primary>syslog</primary></indexterm>
      <indexterm><primary>log files</primary>
	<secondary><acronym>FTP</acronym></secondary></indexterm>

      <para>The <application>ftpd</application> daemon uses
	&man.syslog.3; to log messages.  By default, the system log
	daemon will write messages related to <acronym>FTP</acronym>
	in <filename>/var/log/xferlog</filename>.  The location of
	the <acronym>FTP</acronym> log can be modified by changing the
	following line in
	<filename>/etc/syslog.conf</filename>:</para>

      <programlisting>ftp.info      /var/log/xferlog</programlisting>

      <indexterm>
	<primary><acronym>FTP</acronym></primary>
	<secondary>anonymous</secondary>
      </indexterm>

      <note>
	<para>Be aware of the potential problems involved with running
	  an anonymous <acronym>FTP</acronym> server.  In particular,
	  think twice about allowing anonymous users to upload files.
	  It may turn out that the <acronym>FTP</acronym> site becomes
	  a forum for the trade of unlicensed commercial software or
	  worse.  If anonymous <acronym>FTP</acronym> uploads are
	  required, then verify the permissions so that these files
	  cannot be read by other anonymous users until they have
	  been reviewed by an administrator.</para>
      </note>
    </sect2>
  </sect1>

  <sect1 xml:id="network-samba">
    <!--
    <sect1info>
      <authorgroup>
	<author>
	  <firstname>Murray</firstname>
	  <surname>Stokely</surname>
	  <contrib>Contributed by </contrib>
	</author>
      </authorgroup>
    </sect1info>
    -->
    <title>File and Print Services for &microsoft.windows; Clients
      (Samba)</title>

    <indexterm><primary>Samba server</primary></indexterm>
    <indexterm><primary>Microsoft Windows</primary></indexterm>
    <indexterm>
      <primary>file server</primary>
      <secondary>Windows clients</secondary>
    </indexterm>
    <indexterm>
      <primary>print server</primary>
      <secondary>Windows clients</secondary>
    </indexterm>

    <para><application>Samba</application> is a popular open source
      software package that provides file and print services using the
      <acronym>SMB/CIFS</acronym> protocol.  This protocol is built
      into &microsoft.windows; systems.  It can be added to
      non-&microsoft.windows; systems by installing the
      <application>Samba</application> client libraries.  The protocol
      allows clients to access shared data and printers.  These shares
      can be mapped as a local disk drive and shared printers can be
      used as if they were local printers.</para>

    <para>On &os;, the <application>Samba</application> client
      libraries can be installed using the
      <package>net/samba410</package> port or package.  The
      client provides the ability for a &os; system to access
      <acronym>SMB/CIFS</acronym> shares in a &microsoft.windows;
      network.</para>

    <para>A &os; system can also be configured to act as a
      <application>Samba</application> server by installing the same
      <package>net/samba410</package> port or package.  This allows the
      administrator to create <acronym>SMB</acronym>/<acronym>CIFS</acronym>
      shares on
      the &os; system which can be accessed by clients running
      &microsoft.windows; or the <application>Samba</application>
      client libraries.</para>

    <sect2>
      <title>Server Configuration</title>

      <para><application>Samba</application> is configured in
	<filename>/usr/local/etc/smb4.conf</filename>.  This file must
	be created before <application>Samba</application>
	can be used.</para>

      <para>A simple <filename>smb4.conf</filename> to share
	directories and printers  with &windows; clients in a
	workgroup is shown here.  For more complex setups
	involving LDAP or Active Directory, it is easier to use
	&man.samba-tool.8; to create the initial
	<filename>smb4.conf</filename>.</para>

      <programlisting>[global]
workgroup = WORKGROUP
server string = Samba Server Version %v
netbios name = ExampleMachine
wins support = Yes
security = user
passdb backend = tdbsam

# Example: share /usr/src accessible only to 'developer' user
[src]
path = /usr/src
valid users = developer
writable  = yes
browsable = yes
read only = no
guest ok = no
public = no
create mask = 0666
directory mask = 0755</programlisting>

      <sect3>
	<title>Global Settings</title>

	<para>Settings that describe the network are added in
	  <filename>/usr/local/etc/smb4.conf</filename>:</para>

	<variablelist>
	  <varlistentry>
	    <term><literal>workgroup</literal></term>

	    <listitem>
	      <para>The name of the workgroup to be served.</para>
	    </listitem>
	  </varlistentry>

	  <varlistentry>
	    <term><literal>netbios name</literal></term>

	    <listitem>
	      <para>The NetBIOS name by which a
		<application>Samba</application> server is known.  By
		default, it is the same as the first component of the
		host's <acronym>DNS</acronym> name.</para>
	    </listitem>
	  </varlistentry>

	  <varlistentry>
	    <term><literal>server string</literal></term>

	    <listitem>
	      <para>The string that will be displayed in the output of
		<command>net view</command> and some other
		networking tools that seek to display descriptive text
		about the server.</para>
	    </listitem>
	  </varlistentry>

	  <varlistentry>
	    <term><literal>wins support</literal></term>

	    <listitem>
	      <para>Whether <application>Samba</application> will
		act as a <acronym>WINS</acronym> server.  Do not
		enable support for <acronym>WINS</acronym> on more than
		one server on the network.</para>
	    </listitem>
	  </varlistentry>
	</variablelist>
      </sect3>

      <sect3>
	<title>Security Settings</title>

	<para>The most important settings in
	  <filename>/usr/local/etc/smb4.conf</filename> are the
	  security model and the backend password format.  These
	  directives control the options:</para>

	<variablelist>
	  <varlistentry>
	    <term><literal>security</literal></term>

	    <listitem>
	      <para>The most common settings are
		<literal>security = share</literal> and
		<literal>security = user</literal>.  If the clients
		use usernames that are the same as their usernames on
		the &os; machine, user level security should be
		used.  This is the default security policy and it
		requires clients to first log on before they can
		access shared resources.</para>

	      <para>In share level security, clients do not need to
		log onto the server with a valid username and password
		before attempting to connect to a shared resource.
		This was the default security model for older versions
		of <application>Samba</application>.</para>
	    </listitem>
	  </varlistentry>

	  <varlistentry>
	    <term><literal>passdb backend</literal></term>

	    <listitem>
	      <indexterm><primary>NIS+</primary></indexterm>
	      <indexterm><primary>LDAP</primary></indexterm>
	      <indexterm><primary>SQL database</primary></indexterm>

	      <para><application>Samba</application> has several
		different backend authentication models.  Clients may
		be authenticated with LDAP, NIS+, an SQL database,
		or a modified password file.  The recommended
		authentication method, <literal>tdbsam</literal>,
		is ideal for simple networks and is covered here.
		For larger or more complex networks,
		<literal>ldapsam</literal> is recommended.
		<literal>smbpasswd</literal>
		was the former default and is now obsolete.</para>
	    </listitem>
	  </varlistentry>
	</variablelist>

      </sect3>

      <sect3>
	<title><application>Samba</application> Users</title>

	<para>&os; user accounts must be mapped to the
	  <literal>SambaSAMAccount</literal> database for
	  &windows; clients to access the share.
	  Map existing &os; user accounts using
	  &man.pdbedit.8;:</para>

	<screen>&prompt.root; <userinput>pdbedit -a <replaceable>username</replaceable></userinput></screen>

	<para>This section has only mentioned the most commonly used
	  settings.  Refer to the <link
	    xlink:href="https://wiki.samba.org">Official
	    Samba Wiki</link> for additional information about the
	  available configuration options.</para>
      </sect3>
    </sect2>

    <sect2>
      <title>Starting <application>Samba</application></title>

      <para>To enable <application>Samba</application> at boot time,
	add the following line to
	<filename>/etc/rc.conf</filename>:</para>

      <programlisting>samba_server_enable="YES"</programlisting>

      <para>To start <application>Samba</application> now:</para>

      <screen>&prompt.root; <userinput>service samba_server start</userinput>
Performing sanity check on Samba configuration: OK
Starting nmbd.
Starting smbd.</screen>

      <para><application>Samba</application> consists of three
	separate daemons.  Both the <application>nmbd</application>
	and <application>smbd</application> daemons are started by
	<varname>samba_enable</varname>.  If winbind name resolution
	is also required, set:</para>

	<programlisting>winbindd_enable="YES"</programlisting>

      <para><application>Samba</application> can be stopped at any
	time by typing:</para>

      <screen>&prompt.root; <userinput>service samba_server stop</userinput></screen>

      <para><application>Samba</application> is a complex software
	suite with functionality that allows broad integration with
	&microsoft.windows; networks.  For more information about
	functionality beyond the basic configuration described here,
	refer to <uri
	  xlink:href="https://www.samba.org">https://www.samba.org</uri>.</para>
    </sect2>
  </sect1>

  <sect1 xml:id="network-ntp">
    <!--
    <sect1info>
      <authorgroup>
	<author>
	  <firstname>Tom</firstname>
	  <surname>Hukins</surname>
	  <contrib>Contributed by </contrib>
	</author>
      </authorgroup>
    </sect1info>
    -->
    <title>Clock Synchronization with NTP</title>

    <indexterm><primary>NTP</primary>
      <secondary>ntpd</secondary>
    </indexterm>

    <para>Over time, a computer's clock is prone to drift.   This is
      problematic as many network services require the computers on a
      network to share the same accurate time.  Accurate time is also
      needed to ensure that file timestamps stay consistent.  The
      Network Time Protocol (<acronym>NTP</acronym>) is one way to
      provide clock accuracy in a network.</para>

    <para>&os; includes &man.ntpd.8; which can be configured to query
      other <acronym>NTP</acronym> servers to synchronize the clock on
      that machine or to provide time services to other computers in
      the network.</para>

    <para>This section describes how to configure
      <application>ntpd</application> on &os;.  Further documentation
      can be found in <filename>/usr/share/doc/ntp/</filename> in HTML
      format.</para>

    <sect2>
      <title><acronym>NTP</acronym> Configuration</title>

      <indexterm><primary>NTP</primary></indexterm>

      <para>On &os;, the built-in <application>ntpd</application> can
	be used to synchronize a system's clock.
	<application>Ntpd</application> is configured using &man.rc.conf.5;
	variables and <filename>/etc/ntp.conf</filename>, as detailed
	in the following sections.</para>

      <para><application>Ntpd</application> communicates with its network
        peers using UDP packets.  Any firewalls between your machine and
	its NTP peers must be configured to allow UDP packets in and out
	on port 123.</para>

      <sect3>
	<title>The <filename>/etc/ntp.conf</filename> file</title>

	<indexterm><primary>NTP</primary>
	  <secondary>ntp.conf</secondary>
	</indexterm>

	<para><application>Ntpd</application> reads
	  <filename>/etc/ntp.conf</filename>
	  to determine which <acronym>NTP</acronym> servers to query.
	  Choosing several <acronym>NTP</acronym> servers is recommended
	    in case one of the servers becomes unreachable or its clock proves
	    unreliable.  As <application>ntpd</application> receives responses,
	    it favors reliable servers over the less reliable ones.  The servers
	    which are queried can be local to the network, provided by an
	    <acronym>ISP</acronym>, or selected from an <link
	      xlink:href="http://support.ntp.org/bin/view/Servers/WebHome">
	      online list of publicly accessible <acronym>NTP</acronym>
	      servers</link>.
	    When choosing a public <acronym>NTP</acronym> server, select one
	    that is geographically close and review its usage policy.  The
	    <literal>pool</literal> configuration keyword selects one or more
	    servers from a pool of servers.  An <link
	      xlink:href="http://support.ntp.org/bin/view/Servers/NTPPoolServers">
	      online list of publicly accessible <acronym>NTP</acronym>
	      pools</link>
	    is available, organized by geographic area.  In addition, &os;
	    provides a project-sponsored pool,
	    <literal>0.freebsd.pool.ntp.org</literal>.</para>

	<example>
	  <title>Sample <filename>/etc/ntp.conf</filename></title>
	  <para>This is a simple example of an <filename>ntp.conf</filename>
	    file.  It can safely be used as-is; it contains the recommended
	    <literal>restrict</literal> options for operation on a
	    publicly-accessible network connection.</para>
	  <programlisting>
# Disallow ntpq control/query access.  Allow peers to be added only
# based on pool and server statements in this file.
restrict default limited kod nomodify notrap noquery nopeer
restrict source  limited kod nomodify notrap noquery

# Allow unrestricted access from localhost for queries and control.
restrict 127.0.0.1
restrict ::1

# Add a specific server.
server ntplocal.example.com iburst

# Add FreeBSD pool servers until 3-6 good servers are available.
tos minclock 3 maxclock 6
pool 0.freebsd.pool.ntp.org iburst

# Use a local leap-seconds file.
leapfile "/var/db/ntpd.leap-seconds.list"</programlisting></example>

	<para>The format of this file is described in &man.ntp.conf.5;.
	  The descriptions below provide a quick overview of just the
	  keywords used in the sample file above.</para>

	<para>By default, an <acronym>NTP</acronym> server is accessible
	  to any network host.  The <literal>restrict</literal> keyword
	  controls which systems can access the server.  Multiple
	  <literal>restrict</literal> entries are supported, each one
	  refining the restrictions given in previous statements.  The
	  values shown in the example grant the local system full query
	  and control access, while allowing remote systems only the
	  ability to query the time.  For more details, refer to the
	  <literal>Access Control Support</literal> subsection of
	  &man.ntp.conf.5;.</para>

	<para>The <literal>server</literal> keyword specifies a single
	  server to query.  The file can contain multiple server keywords,
	  with one server listed on each line.  The <literal>pool</literal>
	  keyword specifies a pool of servers.
	  <application>Ntpd</application> will add one or more
	  servers from this pool as needed to reach the number of peers
	  specified using the <literal>tos minclock</literal> value.  The
	  <literal>iburst</literal> keyword directs
	  <application>ntpd</application> to perform a burst of eight quick
	  packet exchanges with a server when contact is first established,
	  to help quickly synchronize system time.</para>

	<para>The <literal>leapfile</literal> keyword specifies the location
	  of a file containing information about leap seconds.  The file is
	  updated automatically by &man.periodic.8;.  The file location
	  specified by this keyword must match the location set in the
	  <literal>ntp_db_leapfile</literal> variable in
	  <filename>/etc/rc.conf</filename>.</para>
      </sect3>

      <sect3>
	<title>NTP entries in <filename>/etc/rc.conf</filename></title>

	<indexterm><primary>NTP</primary>
	  <secondary>rc.conf</secondary>
	</indexterm>

	<para>Set <literal>ntpd_enable=YES</literal> to start
	  <application>ntpd</application> at boot time.  Once
	  <literal>ntpd_enable=YES</literal> has been added
	  to <filename>/etc/rc.conf</filename>,
	  <application>ntpd</application> can be started immediately without
	  rebooting the system by typing:</para>

	<screen>&prompt.root; <userinput>service ntpd start</userinput></screen>

	<para>Only <literal>ntpd_enable</literal> must be set to use ntpd.
	The <filename>rc.conf</filename> variables listed below may also be
	set as needed.</para>

	<para>Set <literal>ntpd_sync_on_start=YES</literal> to allow
	  <application>ntpd</application> to step the clock any amount, one
	  time at startup.  Normally <application>ntpd</application> will
	  log an error message and exit if the clock is off by more than
	  1000 seconds.  This option is especially useful on systems without
	  a battery-backed realtime clock.</para>

	<para>Set <literal>ntpd_oomprotect=YES</literal> to protect the
	  <application>ntpd</application> daemon from being killed by
	  the system attempting to recover from an Out Of Memory
	  (<acronym>OOM</acronym>) condition.</para>

        <para>Set <literal>ntpd_config=</literal> to the location of
	  an alternate <filename>ntp.conf</filename> file.</para>

	<para>Set <literal>ntpd_flags=</literal> to contain any other
	  <application>ntpd</application> flags as needed, but avoid using
	  these flags which are managed internally by
	  <filename>/etc/rc.d/ntpd</filename>:
	  <itemizedlist spacing='compact'>
	    <listitem><para>
	      <literal>-p</literal> (pid file location)</para></listitem>
	    <listitem><para>
	      <literal>-c</literal> (set <literal>ntpd_config=</literal>
	      instead)</para></listitem>
	  </itemizedlist></para>
      </sect3>

      <sect3>
	<title><application>Ntpd</application> and the unpriveleged
	  <literal>ntpd</literal> user</title>

	<para><application>Ntpd</application> on &os; can start and
	  run as an unpriveleged user.  Doing so requires the
	  &man.mac.ntpd.4; policy module.  The
	  <filename>/etc/rc.d/ntpd</filename> startup script first
	  examines the NTP configuration.  If possible, it loads the
	  <literal>mac_ntpd</literal> module, then starts
	  <application>ntpd</application> as unpriveleged user
	  <literal>ntpd</literal> (user id 123).
	  To avoid problems with file and directory access, the startup
	  script will not automatically start
	  <application>ntpd</application> as <literal>ntpd</literal>
	  when the configuration contains any file-related options.</para>

	<para>The presence of any of the following in
	  <literal>ntpd_flags</literal> requires manual configuration
	  as described below to run as the <literal>ntpd</literal> user:
	  <itemizedlist spacing='compact'>
	    <listitem><para>-f or --driftfile</para></listitem>
	    <listitem><para>-i or --jaildir</para></listitem>
	    <listitem><para>-k or --keyfile</para></listitem>
	    <listitem><para>-l or --logfile</para></listitem>
	    <listitem><para>-s or --statsdir</para></listitem>
	  </itemizedlist></para>

	<para>The presence of any of the following keywords in
	  <filename>ntp.conf</filename> requires manual configuration
	  as described below to run as the <literal>ntpd</literal> user:
	  <itemizedlist spacing='compact'>
	    <listitem><para>crypto</para></listitem>
	    <listitem><para>driftfile</para></listitem>
	    <listitem><para>key</para></listitem>
	    <listitem><para>logdir</para></listitem>
	    <listitem><para>statsdir</para></listitem>
	    </itemizedlist></para>

	<para>To manually configure <application>ntpd</application>
	  to run as user <literal>ntpd</literal> you must:
	  <itemizedlist mark='none' spacing='compact'>
	    <listitem><para>Ensure that the <literal>ntpd</literal>
	      user has access to all the files and directories specified
	      in the configuration.</para></listitem>
	    <listitem><para>Arrange for the <literal>mac_ntpd</literal>
	      module to be loaded or compiled into the kernel.  See
	      &man.mac.ntpd.4; for details.</para></listitem>
	    <listitem><para>Set <literal>ntpd_user="ntpd"</literal> in
	      <filename>/etc/rc.conf</filename></para></listitem>
	  </itemizedlist></para>
      </sect3>
    </sect2>

    <sect2>
      <title>Using <acronym>NTP</acronym> with a
	<acronym>PPP</acronym> Connection</title>

      <para><application>ntpd</application> does not need a permanent
	connection to the Internet to function properly.  However, if
	a <acronym>PPP</acronym> connection is configured to dial out
	on demand, <acronym>NTP</acronym> traffic should be prevented
	from triggering a dial out or keeping the connection alive.
	This can be configured with <literal>filter</literal>
	directives in <filename>/etc/ppp/ppp.conf</filename>.  For
	example:</para>

      <programlisting>set filter dial 0 deny udp src eq 123
# Prevent NTP traffic from initiating dial out
set filter dial 1 permit 0 0
set filter alive 0 deny udp src eq 123
# Prevent incoming NTP traffic from keeping the connection open
set filter alive 1 deny udp dst eq 123
# Prevent outgoing NTP traffic from keeping the connection open
set filter alive 2 permit 0/0 0/0</programlisting>

      <para>For more details, refer to the
	<literal>PACKET FILTERING</literal> section in &man.ppp.8; and
	the examples in
	<filename>/usr/share/examples/ppp/</filename>.</para>

      <note>
	<para>Some Internet access providers block low-numbered ports,
	  preventing NTP from functioning since replies never reach
	  the machine.</para>
      </note>
    </sect2>
  </sect1>

  <sect1 xml:id="network-iscsi">
    <!--
    <sect1info>
      <authorgroup>
	<author>
	  <firstname>Edward Tomasz</firstname>
	  <surname>Napierala</surname>
	</author>
      </authorgroup>
    </sect1info>
          -->

    <title><acronym>iSCSI</acronym> Initiator and Target
      Configuration</title>

    <para><acronym>iSCSI</acronym> is a way to share storage over a
      network.  Unlike <acronym>NFS</acronym>, which works at the file
      system level, <acronym>iSCSI</acronym> works at the block device
      level.</para>

    <para>In <acronym>iSCSI</acronym> terminology, the system that
      shares the storage is known as the <emphasis>target</emphasis>.
      The storage can be a physical disk, or an area representing
      multiple disks or a portion of a physical disk.  For example, if
      the disk(s) are formatted with <acronym>ZFS</acronym>, a zvol
      can be created to use as the <acronym>iSCSI</acronym>
      storage.</para>

    <para>The clients which access the <acronym>iSCSI</acronym>
      storage are called <emphasis>initiators</emphasis>.  To
      initiators, the storage available through
      <acronym>iSCSI</acronym> appears as a raw, unformatted disk
      known as a <acronym>LUN</acronym>.  Device nodes for the disk
      appear in <filename>/dev/</filename> and the device must be
      separately formatted and mounted.</para>

    <para>&os; provides a native,
      kernel-based <acronym>iSCSI</acronym> target and initiator.
      This section describes how to configure a &os; system as a
      target or an initiator.</para>

    <sect2 xml:id="network-iscsi-target">
      <title>Configuring an <acronym>iSCSI</acronym> Target</title>

      <para>To configure an <acronym>iSCSI</acronym> target, create
	the <filename>/etc/ctl.conf</filename> configuration file, add
	a line to <filename>/etc/rc.conf</filename> to make sure the
	&man.ctld.8; daemon is automatically started at boot, and then
	start the daemon.</para>

      <para>The following is an example of a simple
	<filename>/etc/ctl.conf</filename> configuration file.  Refer
	to &man.ctl.conf.5; for a more complete description of this
	file's available options.</para>

      <programlisting>portal-group pg0 {
	discovery-auth-group no-authentication
	listen 0.0.0.0
	listen [::]
}

target iqn.2012-06.com.example:target0 {
	auth-group no-authentication
	portal-group pg0

	lun 0 {
		path /data/target0-0
		size 4G
	}
}</programlisting>

      <para>The first entry defines the <literal>pg0</literal> portal
	group.  Portal groups define which network addresses the
	&man.ctld.8; daemon will listen on.  The
	<literal>discovery-auth-group no-authentication</literal>
	entry indicates that any initiator is allowed to perform
	<acronym>iSCSI</acronym> target discovery without
	authentication.  Lines three and four configure &man.ctld.8;
	to listen on all <acronym>IPv4</acronym>
	(<literal>listen 0.0.0.0</literal>) and
	<acronym>IPv6</acronym> (<literal>listen [::]</literal>)
	addresses on the default port of 3260.</para>

      <para>It is not necessary to define a portal group as there is a
	built-in portal group called <literal>default</literal>.  In
	this case, the difference between <literal>default</literal>
	and <literal>pg0</literal> is that with
	<literal>default</literal>, target discovery is always denied,
	while with <literal>pg0</literal>, it is always
	allowed.</para>

      <para>The second entry defines a single target.  Target has two
	possible meanings: a machine serving <acronym>iSCSI</acronym>
	or a named group of <acronym>LUNs</acronym>.  This example
	uses the latter meaning, where
	<literal>iqn.2012-06.com.example:target0</literal> is the
	target name.  This target name is suitable for testing
	purposes.  For actual use, change
	<literal>com.example</literal> to the real domain name,
	reversed.  The <literal>2012-06</literal> represents the year
	and month of acquiring control of that domain name, and
	<literal>target0</literal> can be any value.  Any number of
	targets can be defined in this configuration file.</para>

      <para>The <literal>auth-group no-authentication</literal> line
	allows all initiators to connect to the specified target and
	<literal>portal-group pg0</literal> makes the target reachable
	through the <literal>pg0</literal> portal group.</para>

      <para>The next section defines the <acronym>LUN</acronym>.  To
	the initiator, each <acronym>LUN</acronym> will be visible as
	a separate disk device.  Multiple <acronym>LUNs</acronym> can
	be defined for each target.  Each <acronym>LUN</acronym> is
	identified by a number, where <acronym>LUN</acronym> 0 is
	mandatory.  The <literal>path /data/target0-0</literal> line
	defines the full path to a file or zvol backing the
	<acronym>LUN</acronym>.  That path must exist before starting
	&man.ctld.8;.  The second line is optional and specifies the
	size of the <acronym>LUN</acronym>.</para>

      <para>Next, to make sure the &man.ctld.8; daemon is started at
	boot, add this line to
	<filename>/etc/rc.conf</filename>:</para>

      <programlisting>ctld_enable="YES"</programlisting>

      <para>To start &man.ctld.8; now, run this command:</para>

      <screen>&prompt.root; <userinput>service ctld start</userinput></screen>

      <para>As the &man.ctld.8; daemon is started, it reads
	<filename>/etc/ctl.conf</filename>.  If this file is edited
	after the daemon starts, use this command so that the changes
	take effect immediately:</para>

      <screen>&prompt.root; <userinput>service ctld reload</userinput></screen>

      <sect3>
	<title>Authentication</title>

	<para>The previous example is inherently insecure as it uses
	  no authentication, granting anyone full access to all
	  targets.  To require a username and password to access
	  targets, modify the configuration as follows:</para>

	<programlisting>auth-group ag0 {
	chap username1 secretsecret
	chap username2 anothersecret
}

portal-group pg0 {
	discovery-auth-group no-authentication
	listen 0.0.0.0
	listen [::]
}

target iqn.2012-06.com.example:target0 {
	auth-group ag0
	portal-group pg0
	lun 0 {
		path /data/target0-0
		size 4G
	}
}</programlisting>

	<para>The <literal>auth-group</literal> section defines
	  username and password pairs.  An initiator trying to connect
	  to <literal>iqn.2012-06.com.example:target0</literal> must
	  first specify a defined username and secret.  However,
	  target discovery is still permitted without authentication.
	  To require target discovery authentication, set
	  <literal>discovery-auth-group</literal> to a defined
	  <literal>auth-group</literal> name instead of
	  <literal>no-authentication</literal>.</para>

	<para>It is common to define a single exported target for
	  every initiator.  As a shorthand for the syntax above, the
	  username and password can be specified directly in the
	  target entry:</para>

	<programlisting>target iqn.2012-06.com.example:target0 {
	portal-group pg0
	chap username1 secretsecret

	lun 0 {
		path /data/target0-0
		size 4G
	}
}</programlisting>
      </sect3>
    </sect2>

    <sect2 xml:id="network-iscsi-initiator">
      <title>Configuring an <acronym>iSCSI</acronym> Initiator</title>

      <note>
	<para>The <acronym>iSCSI</acronym> initiator described in this
	  section is supported starting with &os; 10.0-RELEASE.  To
	  use the <acronym>iSCSI</acronym> initiator available in
	  older versions, refer to &man.iscontrol.8;.</para>
      </note>

      <para>The <acronym>iSCSI</acronym> initiator requires that the
	&man.iscsid.8; daemon is running.  This daemon does not use a
	configuration file.  To start it automatically at boot, add
	this line to <filename>/etc/rc.conf</filename>:</para>

      <programlisting>iscsid_enable="YES"</programlisting>

      <para>To start &man.iscsid.8; now, run this command:</para>

      <screen>&prompt.root; <userinput>service iscsid start</userinput></screen>

      <para>Connecting to a target can be done with or without an
	<filename>/etc/iscsi.conf</filename> configuration file.  This
	section demonstrates both types of connections.</para>

      <sect3>
	<title>Connecting to a Target Without a Configuration
	  File</title>

	<para>To connect an initiator to a single target, specify the
	  <acronym>IP</acronym> address of the portal and the name of
	  the target:</para>

	<screen>&prompt.root; <userinput>iscsictl -A -p <replaceable>10.10.10.10</replaceable> -t <replaceable>iqn.2012-06.com.example:target0</replaceable></userinput></screen>

	<para>To verify if the connection succeeded, run
	  <command>iscsictl</command> without any arguments.  The
	  output should look similar to this:</para>

	<programlisting>Target name                                     Target portal   State
iqn.2012-06.com.example:target0                 10.10.10.10     Connected: da0</programlisting>

	<para>In this example, the <acronym>iSCSI</acronym> session
	  was successfully established, with
	  <filename>/dev/da0</filename> representing the attached
	  <acronym>LUN</acronym>.  If the
	  <literal>iqn.2012-06.com.example:target0</literal> target
	  exports more than one <acronym>LUN</acronym>, multiple
	  device nodes will be shown in that section of the
	  output:</para>

	<screen>Connected: da0 da1 da2.</screen>

	<para>Any errors will be reported in the output, as well as
	  the system logs.  For example, this message usually means
	  that the &man.iscsid.8; daemon is not running:</para>

	<programlisting>Target name                                     Target portal   State
iqn.2012-06.com.example:target0                 10.10.10.10     Waiting for iscsid(8)</programlisting>

	<para>The following message suggests a networking problem,
	  such as a wrong <acronym>IP</acronym> address or
	  port:</para>

	<programlisting>Target name                                     Target portal   State
iqn.2012-06.com.example:target0                 10.10.10.11     Connection refused</programlisting>

	<para>This message means that the specified target name is
	  wrong:</para>

	<programlisting>Target name                                     Target portal   State
iqn.2012-06.com.example:target0                 10.10.10.10     Not found</programlisting>

	<para>This message means that the target requires
	  authentication:</para>

	<programlisting>Target name                                     Target portal   State
iqn.2012-06.com.example:target0                 10.10.10.10     Authentication failed</programlisting>

	<para>To specify a <acronym>CHAP</acronym> username and
	  secret, use this syntax:</para>

	<screen>&prompt.root; <userinput>iscsictl -A -p <replaceable>10.10.10.10</replaceable> -t <replaceable>iqn.2012-06.com.example:target0</replaceable> -u <replaceable>user</replaceable> -s <replaceable>secretsecret</replaceable></userinput></screen>
      </sect3>

      <sect3>
	<title>Connecting to a Target with a Configuration
	  File</title>

	<para>To connect using a configuration file, create
	  <filename>/etc/iscsi.conf</filename> with contents like
	  this:</para>

	<programlisting>t0 {
	TargetAddress   = 10.10.10.10
	TargetName      = iqn.2012-06.com.example:target0
	AuthMethod      = CHAP
	chapIName       = user
	chapSecret      = secretsecret
}</programlisting>

	<para>The <literal>t0</literal> specifies a nickname for the
	  configuration file section.  It will be used by the
	  initiator to specify which configuration to use.  The other
	  lines specify the parameters to use during connection.  The
	  <literal>TargetAddress</literal> and
	  <literal>TargetName</literal> are mandatory, whereas the
	  other options are optional.  In this example, the
	  <acronym>CHAP</acronym> username and secret are
	  shown.</para>

	<para>To connect to the defined target, specify the
	  nickname:</para>

	<screen>&prompt.root; <userinput>iscsictl -An <replaceable>t0</replaceable></userinput></screen>

	<para>Alternately, to connect to all targets defined in the
	  configuration file, use:</para>

	<screen>&prompt.root; <userinput>iscsictl -Aa</userinput></screen>

	<para>To make the initiator automatically connect to all
	  targets in <filename>/etc/iscsi.conf</filename>, add the
	  following to <filename>/etc/rc.conf</filename>:</para>

	<programlisting>iscsictl_enable="YES"
iscsictl_flags="-Aa"</programlisting>

      </sect3>
    </sect2>
  </sect1>

</chapter>