path: root/docs/manpages-3/winbindd.8.xml

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<!DOCTYPE refentry PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc">
<refentry id="winbindd.8">

<refmeta>
	<refentrytitle>winbindd</refentrytitle>
	<manvolnum>8</manvolnum>
</refmeta>


<refnamediv>
	<refname>winbindd</refname>
	<refpurpose>Name Service Switch daemon for resolving names 
	from NT servers</refpurpose>
</refnamediv>

<refsynopsisdiv>
	<cmdsynopsis>
		<command>winbindd</command>
		<arg choice="opt">-F</arg>
		<arg choice="opt">-S</arg>
		<arg choice="opt">-i</arg>
		<arg choice="opt">-Y</arg>
		<arg choice="opt">-d &lt;debug level&gt;</arg>
		<arg choice="opt">-s &lt;smb config file&gt;</arg>
		<arg choice="opt">-n</arg>
	</cmdsynopsis>
</refsynopsisdiv>

<refsect1>
	<title>DESCRIPTION</title>

	<para>This program is part of the <citerefentry><refentrytitle>samba</refentrytitle>
	<manvolnum>7</manvolnum></citerefentry> suite.</para>

	<para><command>winbindd</command> is a daemon that provides 
	a number of services to the Name Service Switch capability found
	in most modern C libraries, to arbitary applications via PAM
	and <command>ntlm_auth</command> and to Samba itself.</para>

	<para>Even if winbind is not used for nsswitch, it still provides a
	service to <command>smbd</command>, <command>ntlm_auth</command>
	and the <command>pam_winbind.so</command> PAM module, by managing connections to
	domain controllers.  In this configuraiton the
	<smbconfoption name="idmap uid"/> and
	<smbconfoption name="idmap gid"/>
	parameters are not required. (This is known as `netlogon proxy only mode'.)</para>

        <para> The Name Service Switch allows user 
	and system information to be obtained from different databases 
	services such as NIS or DNS.  The exact behaviour can be configured 
	throught the <filename>/etc/nsswitch.conf</filename> file.  
	Users and groups are allocated as they are resolved to a range 
	of user and group ids specified by the administrator of the 
	Samba system.</para>

	<para>The service provided by <command>winbindd</command> is called `winbind' and 
	can be used to resolve user and group information from a 
	Windows NT server. The service can also provide authentication
	services via an associated PAM module. </para>
	
	<para>
	The <filename>pam_winbind</filename> module supports the
        <parameter>auth</parameter>, <parameter>account</parameter>
        and <parameter>password</parameter>
        module-types.  It should be noted that the 
        <parameter>account</parameter> module simply performs a getpwnam() to verify that
        the system can obtain a uid for the user, as the domain
        controller has already performed access control.  If the
        <filename>libnss_winbind</filename> library has been correctly
        installed, or an alternate source of names configured, this should always succeed.
	</para>

	<para>The following nsswitch databases are implemented by 
	the winbindd service: </para>

	<variablelist>
		<varlistentry>
		<term>hosts</term>
		<listitem><para>This feature is only available on IRIX.
		User information traditionally stored in 
		the <filename>hosts(5)</filename> file and used by 
		<command>gethostbyname(3)</command> functions. Names are
		resolved through the WINS server or by broadcast.
		</para></listitem>
		</varlistentry>

		<varlistentry>
		<term>passwd</term>
		<listitem><para>User information traditionally stored in 
		the <filename>passwd(5)</filename> file and used by 
		<command>getpwent(3)</command> functions. </para></listitem>
		</varlistentry>

		<varlistentry>
		<term>group</term>
		<listitem><para>Group information traditionally stored in 
		the <filename>group(5)</filename> file and used by 		
		<command>getgrent(3)</command> functions. </para></listitem>
		</varlistentry>
	</variablelist>

	<para>For example, the following simple configuration in the
	<filename>/etc/nsswitch.conf</filename> file can be used to initially 
	resolve user and group information from <filename>/etc/passwd
	</filename> and <filename>/etc/group</filename> and then from the 
	Windows NT server.
<programlisting>
passwd:         files winbind
group:          files winbind
## only available on IRIX; Linux users should us libnss_wins.so
hosts:          files dns winbind
</programlisting></para>  

	<para>The following simple configuration in the
	<filename>/etc/nsswitch.conf</filename> file can be used to initially
	resolve hostnames from <filename>/etc/hosts</filename> and then from the
	WINS server.</para>
<programlisting>
hosts:		files wins
</programlisting>

</refsect1>


<refsect1>
	<title>OPTIONS</title>

	<variablelist>
		<varlistentry>
		<term>-F</term>
		<listitem><para>If specified, this parameter causes
		the main <command>winbindd</command> process to not daemonize,
		i.e. double-fork and disassociate with the terminal.
		Child processes are still created as normal to service
		each connection request, but the main process does not
		exit. This operation mode is suitable for running
		<command>winbindd</command> under process supervisors such
		as <command>supervise</command> and <command>svscan</command>
		from Daniel J. Bernstein's <command>daemontools</command>
		package, or the AIX process monitor.
		</para></listitem>
		</varlistentry>

		<varlistentry>
		<term>-S</term>
		<listitem><para>If specified, this parameter causes
		<command>winbindd</command> to log to standard output rather
		than a file.</para></listitem>
		</varlistentry>

		&popt.common.samba;
		&stdarg.help;

		<varlistentry>
		<term>-i</term>
		<listitem><para>Tells <command>winbindd</command> to not 
		become a daemon and detach from the current terminal. This 
		option is used by developers when interactive debugging 
		of <command>winbindd</command> is required.
		<command>winbindd</command> also logs to standard output,
		as if the <command>-S</command> parameter had been given.
		</para></listitem>
		</varlistentry>

		<varlistentry>
		<term>-n</term>
		<listitem><para>Disable caching. This means winbindd will 
		always have to wait for a response from the domain controller 
		before it can respond to a client and this thus makes things 
		slower. The results will however be more accurate, since 
		results from the cache might not be up-to-date. This 
		might also temporarily hang winbindd if the DC doesn't respond.
		</para></listitem>
		</varlistentry>

		<varlistentry>
		<term>-Y</term>
		<listitem><para>Single daemon mode. This means winbindd will run 
		as a single process (the mode of operation in Samba 2.2).  Winbindd's 
		default behavior is to launch a child process that is responsible for 
		updating expired cache entries.
		</para></listitem>
		</varlistentry>

	</variablelist>
</refsect1>


<refsect1>
	<title>NAME AND ID RESOLUTION</title>

	<para>Users and groups on a Windows NT server are assigned 
	a security id (SID) which is globally unique when the 
	user or group is created.  To convert the Windows NT user or group 
	into a unix user or group, a mapping between SIDs and unix user 
	and group ids is required.  This is one of the jobs that <command>
	winbindd</command> performs. </para>

	<para>As winbindd users and groups are resolved from a server, user 
	and group ids are allocated from a specified range.  This
	is done on a first come, first served basis, although all existing 
	users and groups will be mapped as soon as a client performs a user 
	or group enumeration command.  The allocated unix ids are stored 
	in a database file under the Samba lock directory and will be 
	remembered. </para>

	<para>WARNING: The SID to unix id database is the only location 
	where the user and group mappings are stored by winbindd.  If this 
	file is deleted or corrupted, there is no way for winbindd to 
	determine which user and group ids correspond to Windows NT user 
	and group rids. </para>

        <para>See the <smbconfoption><name>idmap
        backend</name></smbconfoption> parameter in
        <filename>smb.conf</filename> for options for sharing this
        database, such as via LDAP.</para>
</refsect1>


<refsect1>
	<title>CONFIGURATION</title>

	<para>Configuration of the <command>winbindd</command> daemon 
	is done through configuration parameters in the <citerefentry>
	<refentrytitle>smb.conf</refentrytitle><manvolnum>5</manvolnum>
	</citerefentry> file.  All parameters should be specified in the 
	[global] section of smb.conf. </para>

	<itemizedlist>
		<listitem><para>
		<smbconfoption name="winbind separator"/></para></listitem>
		<listitem><para>
		<smbconfoption name="idmap uid"/></para></listitem>
		<listitem><para>
		<smbconfoption name="idmap gid"/></para></listitem>
		<listitem><para>
		<smbconfoption name="idmap backend"/></para></listitem>
		<listitem><para>
		<smbconfoption name="winbind cache time"/></para></listitem>
		<listitem><para>
		<smbconfoption name="winbind enum users"/></para></listitem>
		<listitem><para>
		<smbconfoption name="winbind enum groups"/></para></listitem>
		<listitem><para>
		<smbconfoption name="template homedir"/></para></listitem>
		<listitem><para>
		<smbconfoption name="template shell"/></para></listitem>
		<listitem><para>
		<smbconfoption name="winbind use default domain"/></para></listitem>
	</itemizedlist>
</refsect1>


<refsect1>
	<title>EXAMPLE SETUP</title>

	<para>
	To setup winbindd for user and group lookups plus 
	authentication from a domain controller use something like the 
	following setup. This was tested on an early Red Hat Linux box.
	</para>

	<para>In <filename>/etc/nsswitch.conf</filename> put the 
	following:
<programlisting>
passwd: files winbind
group:  files winbind
</programlisting>
	</para>  

	<para>In <filename>/etc/pam.d/*</filename> replace the <parameter>
	auth</parameter> lines with something like this:
<programlisting>
auth  required    /lib/security/pam_securetty.so
auth  required	  /lib/security/pam_nologin.so
auth  sufficient  /lib/security/pam_winbind.so
auth  required    /lib/security/pam_unix.so \
                  use_first_pass shadow nullok
</programlisting>
	</para>
  
	<note><para>
	The PAM module pam_unix has recently replaced the module pam_pwdb.
	Some Linux systems use the module pam_unix2 in place of pam_unix.
	</para></note>

	<para>Note in particular the use of the <parameter>sufficient
	</parameter> keyword and the <parameter>use_first_pass</parameter> keyword. </para>

	<para>Now replace the account lines with this: </para> 
	
	<para><command>account    required	/lib/security/pam_winbind.so
	</command></para>
 
  	<para>The next step is to join the domain. To do that use the 
	<command>net</command> program like this:  </para>
 
	<para><command>net join -S PDC -U Administrator</command></para>
 
	<para>The username after the <parameter>-U</parameter> can be any
	Domain user that has administrator privileges on the machine.
	Substitute the name or IP of your PDC for "PDC".</para>

	<para>Next copy <filename>libnss_winbind.so</filename> to 
	<filename>/lib</filename> and <filename>pam_winbind.so
	</filename> to <filename>/lib/security</filename>.  A symbolic link needs to be
	made from <filename>/lib/libnss_winbind.so</filename> to
	<filename>/lib/libnss_winbind.so.2</filename>.  If you are using an
	older version of glibc then the target of the link should be
	<filename>/lib/libnss_winbind.so.1</filename>.</para>

	<para>Finally, setup a <citerefentry><refentrytitle>smb.conf</refentrytitle>
	<manvolnum>5</manvolnum></citerefentry> containing directives like the 
	following:
<programlisting>
[global]
	winbind separator = +
        winbind cache time = 10
        template shell = /bin/bash
        template homedir = /home/%D/%U
        idmap uid = 10000-20000
        idmap gid = 10000-20000
        workgroup = DOMAIN
        security = domain
        password server = *
</programlisting></para>
  

	<para>Now start winbindd and you should find that your user and 
	group database is expanded to include your NT users and groups, 
	and that you can login to your unix box as a domain user, using 
	the DOMAIN+user syntax for the username. You may wish to use the 
	commands <command>getent passwd</command> and <command>getent group
	</command> to confirm the correct operation of winbindd.</para>
</refsect1>


<refsect1>
	<title>NOTES</title>

	<para>The following notes are useful when configuring and 
	running <command>winbindd</command>: </para>

	<para><citerefentry><refentrytitle>nmbd</refentrytitle>
	<manvolnum>8</manvolnum></citerefentry> must be running on the local machine 
	for <command>winbindd</command> to work. </para>

	<para>PAM is really easy to misconfigure.  Make sure you know what 
	you are doing when modifying PAM configuration files.  It is possible 
	to set up PAM such that you can no longer log into your system. </para>
	
	<para>If more than one UNIX machine is running <command>winbindd</command>, 
	then in general the user and groups ids allocated by winbindd will not 
	be the same.  The user and group ids will only be valid for the local 
	machine, unless a shared <smbconfoption><name>idmap
	backend</name></smbconfoption> is configured.</para>

	<para>If the the Windows NT SID to UNIX user and group id mapping 
	file is damaged or destroyed then the mappings will be lost. </para>
</refsect1>


<refsect1>
	<title>SIGNALS</title>

	<para>The following signals can be used to manipulate the 
	<command>winbindd</command> daemon. </para>

	<variablelist>
		<varlistentry>
		<term>SIGHUP</term>
		<listitem><para>Reload the <citerefentry><refentrytitle>smb.conf</refentrytitle>
		<manvolnum>5</manvolnum></citerefentry> file and 
		apply any parameter changes to the running 
		version of winbindd.  This signal also clears any cached 
		user and group information.  The list of other domains trusted 
		by winbindd is also reloaded.  </para></listitem>
		</varlistentry>

		<varlistentry>
		<term>SIGUSR2</term>
		<listitem><para>The SIGUSR2 signal will cause <command>
		winbindd</command> to write status information to the winbind 
		log file.</para>

		<para>Log files are stored in the filename specified by the 
		log file parameter.</para></listitem>
		</varlistentry>
	</variablelist>
</refsect1>

<refsect1>
	<title>FILES</title>

	<variablelist>
		<varlistentry>
		<term><filename>/etc/nsswitch.conf(5)</filename></term>
		<listitem><para>Name service switch configuration file.</para>
		</listitem>
		</varlistentry>
	
		<varlistentry>
		<term>/tmp/.winbindd/pipe</term>
		<listitem><para>The UNIX pipe over which clients communicate with 
		the <command>winbindd</command> program.  For security reasons, the 
		winbind client will only attempt to connect to the winbindd daemon 
		if both the <filename>/tmp/.winbindd</filename> directory
		and <filename>/tmp/.winbindd/pipe</filename> file are owned by 
		root. </para></listitem>
		</varlistentry>

		<varlistentry>
		<term>$LOCKDIR/winbindd_privileged/pipe</term>
	        <listitem><para>The UNIX pipe over which 'privileged' clients 
                communicate with the <command>winbindd</command> program.  For security 
                reasons, access to some winbindd functions - like those needed by 
                the <command>ntlm_auth</command> utility - is restricted.  By default,
                only users in the 'root' group will get this access, however the administrator
                may change the group permissions on $LOCKDIR/winbindd_privileged to allow
                programs like 'squid' to use ntlm_auth.
		Note that the winbind client will only attempt to connect to the winbindd daemon 
		if both the <filename>$LOCKDIR/winbindd_privileged</filename> directory
		and <filename>$LOCKDIR/winbindd_privileged/pipe</filename> file are owned by 
		root. </para></listitem>
		</varlistentry>

		<varlistentry>
		<term>/lib/libnss_winbind.so.X</term>
		<listitem><para>Implementation of name service switch library.
		</para></listitem>
		</varlistentry>
	
		<varlistentry>
		<term>$LOCKDIR/winbindd_idmap.tdb</term>
		<listitem><para>Storage for the Windows NT rid to UNIX user/group 
		id mapping.  The lock directory is specified when Samba is initially 
		compiled using the <parameter>--with-lockdir</parameter> option.
		This directory is by default <filename>/usr/local/samba/var/locks
		</filename>. </para></listitem>
		</varlistentry>
	
		<varlistentry>
		<term>$LOCKDIR/winbindd_cache.tdb</term>
		<listitem><para>Storage for cached user and group information.
		</para></listitem>
		</varlistentry>
	</variablelist>
</refsect1>


<refsect1>
	<title>VERSION</title>

	<para>This man page is correct for version 3.0 of
        the Samba suite.</para>
</refsect1>

<refsect1>
	<title>SEE ALSO</title>
	
	<para><filename>nsswitch.conf(5)</filename>, <citerefentry>
	<refentrytitle>samba</refentrytitle>
	<manvolnum>7</manvolnum></citerefentry>, <citerefentry>
	<refentrytitle>wbinfo</refentrytitle>
	<manvolnum>1</manvolnum></citerefentry>, <citerefentry>
	<refentrytitle>ntlm_auth</refentrytitle>
	<manvolnum>8</manvolnum></citerefentry>, <citerefentry>
	<refentrytitle>smb.conf</refentrytitle>
	<manvolnum>5</manvolnum></citerefentry>, <citerefentry>
	<refentrytitle>pam_winbind</refentrytitle>
	<manvolnum>8</manvolnum></citerefentry></para>
</refsect1>

<refsect1>
	<title>AUTHOR</title>
	
	<para>The original Samba software and related utilities 
	were created by Andrew Tridgell. Samba is now developed
	by the Samba Team as an Open Source project similar 
	to the way the Linux kernel is developed.</para>
	
	<para><command>wbinfo</command> and <command>winbindd</command> were 
	written by Tim Potter.</para>
	
	<para>The conversion to DocBook for Samba 2.2 was done 
	by Gerald Carter. The conversion to DocBook XML 4.2 for
	Samba 3.0 was done by Alexander Bokovoy.</para>
</refsect1>

</refentry>