path: root/docs/Samba3-HOWTO/TOSHARG-Passdb.xml

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<!DOCTYPE chapter PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc">
<chapter id="passdb">
<chapterinfo>
	&author.jelmer;
	&author.jht;
	&author.jerry;
	&author.jeremy;
	<author>&person.gd;<contrib>LDAP updates</contrib></author>
	<author>
		<firstname>Olivier (lem)</firstname><surname>Lemaire</surname>
		<affiliation>
			<orgname>IDEALX</orgname>
			<address><email>olem@IDEALX.org</email></address>
		</affiliation>
	</author>
	
	<pubdate>May 24, 2003</pubdate>
</chapterinfo>
<title>Account Information Databases</title>

<para>
<indexterm><primary>account backends</primary></indexterm>
<indexterm><primary>password backends</primary></indexterm>
<indexterm><primary>scalability</primary></indexterm>
<indexterm><primary>ADS</primary></indexterm>
Samba-3 implements a new capability to work concurrently with multiple account backends.
The possible new combinations of password backends allows Samba-3 a degree of flexibility
and scalability that previously could be achieved only with MS Windows Active Directory (ADS).
This chapter describes the new functionality and how to get the most out of it.
</para>

<para>
<indexterm><primary>passdb backend</primary></indexterm>
<indexterm><primary>smbpasswd</primary></indexterm>
<indexterm><primary>tdbsam</primary></indexterm>
<indexterm><primary>ldapsam</primary></indexterm>
<indexterm><primary>LDAP</primary></indexterm>
<indexterm><primary>single repository</primary></indexterm>
The three passdb backends that are fully maintained (actively supported) by the Samba Team are:
<literal>smbpasswd</literal> (being obsoleted), <literal>tdbsam</literal> (a tdb-based binary file format),
and <literal>ldapsam</literal> (LDAP directory).  Of these, only the <literal>ldapsam</literal> backend
stores both POSIX (UNIX) and Samba user and group account information in a single repository. The
<literal>smbpasswd</literal> and <literal>tdbsam</literal> backends store only Samba user accounts.
</para>

<para>
In a strict sense, there are three supported account storage and access systems. One of these is considered
obsolete (smbpasswd). It is recommended to use the <literal>tdbsam</literal> method for all simple systems. Use
<literal>ldapsam</literal> for larger and more complex networks.
</para>

<para>
<indexterm><primary>passdb backend</primary></indexterm>
<indexterm><primary>account storage mechanisms</primary></indexterm>
<indexterm><primary>account storage system</primary></indexterm>
<indexterm><primary>user and trust accounts</primary></indexterm>
<indexterm><primary>machine trust accounts</primary></indexterm>
<indexterm><primary>computer accounts</primary></indexterm>
<indexterm><primary>interdomain trust accounts</primary></indexterm>
In a strict and literal sense, the passdb backends are account storage mechanisms (or methods) alone. The choice
of terminology can be misleading, however we are stuck with this choice of wording. This chapter documents the
nature of the account storage system with a focus on user and trust accounts. Trust accounts have two forms,
machine trust accounts (computer accounts) and interdomain trust accounts. These are all treated as user-like
entities.
</para>

<sect1>
<title>Features and Benefits</title>

<para>
Samba-3 provides for complete backward compatibility with Samba-2.2.x functionality
as follows:
<indexterm><primary>SAM backend</primary><secondary>smbpasswd</secondary></indexterm>
<indexterm><primary>SAM backend</primary><secondary>ldapsam_compat</secondary></indexterm>
<indexterm><primary>encrypted passwords</primary></indexterm>
</para>

<sect2>
	<title>Backward Compatibility Account Storage Systems</title>

<variablelist>
	<varlistentry><term>Plaintext</term>
		<listitem>
			<para>
<indexterm><primary>plaintext</primary></indexterm>
<indexterm><primary>plaintext authentication</primary></indexterm>
<indexterm><primary>/etc/passwd</primary></indexterm>
<indexterm><primary>/etc/shadow</primary></indexterm>
<indexterm><primary>PAM</primary></indexterm>
			This isn't really a backend at all, but is listed here for simplicity.  Samba can be configured to pass
			plaintext authentication requests to the traditional UNIX/Linux <filename>/etc/passwd</filename> and
			<filename>/etc/shadow</filename>-style subsystems.  On systems that have Pluggable Authentication Modules
			(PAM) support, all PAM modules are supported. The behavior is just as it was with Samba-2.2.x, and the
			protocol limitations imposed by MS Windows clients apply likewise. Please refer to <link
			linkend="passdbtech">Technical Information</link>, for more information regarding the limitations of plaintext
			password usage.
			</para>
		</listitem>
	</varlistentry>

	<varlistentry><term>smbpasswd</term>
		<listitem>
			<para>
<indexterm><primary>smbpasswd</primary></indexterm>
<indexterm><primary>LanMan passwords</primary></indexterm>
<indexterm><primary>NT-encrypted passwords</primary></indexterm>
<indexterm><primary>SAM</primary></indexterm>
			This option allows continued use of the <filename>smbpasswd</filename>
			file that maintains a plain ASCII (text) layout that includes the MS Windows
			LanMan and NT-encrypted passwords as well as a field that stores some
			account information. This form of password backend does not store any of
			the MS Windows NT/200x SAM (Security Account Manager) information required to
			provide the extended controls that are needed for more comprehensive 
			interoperation with MS Windows NT4/200x servers.
			</para>

			<para>
			This backend should be used only for backward compatibility with older
			versions of Samba. It may be deprecated in future releases.
			</para>
		</listitem>
	</varlistentry>

	<varlistentry><term>ldapsam_compat (Samba-2.2 LDAP Compatibility)</term>
		<listitem>
			<para>
<indexterm><primary>ldapsam_compat</primary></indexterm>
<indexterm><primary>Samba-2.2.x LDAP schema</primary></indexterm>
<indexterm><primary>OpenLDAP backend</primary></indexterm>
			There is a password backend option that allows continued operation with
			an existing OpenLDAP backend that uses the Samba-2.2.x LDAP schema extension.
			This option is provided primarily as a migration tool, although there is
			no reason to force migration at this time. This tool will eventually
			be deprecated.
			</para>
		</listitem>
	</varlistentry>
</variablelist>

</sect2>

<sect2>
<title>New Account Storage Systems</title>

<para>
Samba-3 introduces a number of new password backend capabilities.
<indexterm><primary>SAM backend</primary><secondary>tdbsam</secondary></indexterm>
<indexterm><primary>SAM backend</primary><secondary>ldapsam</secondary></indexterm>
</para>

<variablelist>
	<varlistentry><term>tdbsam</term>
		<listitem>
			<para>
<indexterm><primary>rich database backend</primary></indexterm>
<indexterm><primary>PDC</primary></indexterm>
<indexterm><primary>BDC</primary></indexterm>
			This backend provides a rich database backend for local servers. This
			backend is not suitable for multiple domain controllers (i.e., PDC + one
			or more BDC) installations.
			</para>

			<para>
<indexterm><primary>extended SAM</primary></indexterm>
<indexterm><primary>TDB</primary></indexterm>
<indexterm><primary>binary format TDB</primary></indexterm>
<indexterm><primary>trivial database</primary></indexterm>
<indexterm><primary>system access controls</primary></indexterm>
<indexterm><primary>MS Windows NT4/200x</primary></indexterm>
			The <emphasis>tdbsam</emphasis> password backend stores the old <emphasis>
			smbpasswd</emphasis> information plus the extended MS Windows NT/200x
			SAM information into a binary format TDB (trivial database) file.
			The inclusion of the extended information makes it possible for Samba-3
			to implement the same account and system access controls that are possible
			with MS Windows NT4/200x-based systems.
			</para>

			<para>
<indexterm><primary>simple operation</primary></indexterm>
<indexterm><primary>OpenLDAP</primary></indexterm>
<indexterm><primary>ADS</primary></indexterm>
			The inclusion of the <emphasis>tdbsam</emphasis> capability is a direct
			response to user requests to allow simple site operation without the overhead
			of the complexities of running OpenLDAP. It is recommended to use this only
			for sites that have fewer than 250 users. For larger sites or implementations,
			the use of OpenLDAP or of Active Directory integration is strongly recommended.
			</para>
		</listitem>
	</varlistentry>

	<varlistentry><term>ldapsam</term>
		<listitem>
			<para>
<indexterm><primary>rich directory backend</primary></indexterm>
<indexterm><primary>distributed account</primary></indexterm>
			This provides a rich directory backend for distributed account installation.	
			</para>

			<para>
<indexterm><primary>LDAP</primary></indexterm>
<indexterm><primary>OpenLDAP</primary></indexterm>
<indexterm><primary>Samba schema</primary></indexterm>
<indexterm><primary>schema file</primary></indexterm>
<indexterm><primary>examples/LDAP</primary></indexterm>
			Samba-3 has a new and extended LDAP implementation that requires configuration
			of OpenLDAP with a new format Samba schema. The new format schema file is
			included in the <filename class="directory">examples/LDAP</filename> directory of the Samba distribution.
			</para>

			<para>
<indexterm><primary>expands control abilities</primary></indexterm>
<indexterm><primary>profile</primary></indexterm>
<indexterm><primary>home directories</primary></indexterm>
<indexterm><primary>account access controls</primary></indexterm>
<indexterm><primary>greater scalability</primary></indexterm>
			The new LDAP implementation significantly expands the control abilities that
			were possible with prior versions of Samba. It is now possible to specify
			<quote>per-user</quote> profile settings, home directories, account access controls, and
			much more. Corporate sites will see that the Samba Team has listened to their
			requests both for capability and greater scalability.
			</para>
		</listitem>
	</varlistentry>

</variablelist>

</sect2>

</sect1>

<sect1 id="passdbtech">
	<title>Technical Information</title>

	<para>
<indexterm><primary>plaintext passwords</primary></indexterm>
<indexterm><primary>encrypted passwords</primary></indexterm>
	Old Windows clients send plaintext passwords over the wire. Samba can check these
	passwords by encrypting them and comparing them to the hash stored in the UNIX user database.
	</para>

	<para>
<indexterm><primary>encrypted passwords</primary></indexterm>	
<indexterm><primary>LanMan</primary></indexterm>
<indexterm><primary>plaintext passwords</primary></indexterm>
<indexterm><primary>registry</primary></indexterm>
	Newer Windows clients send encrypted passwords (LanMan and NT hashes) instead of plaintext passwords over
	the wire. The newest clients will send only encrypted passwords and refuse to send plaintext passwords unless
	their registry is tweaked.
	</para>

	<para>
<indexterm><primary>UNIX-style encrypted passwords</primary></indexterm>
<indexterm><primary>converted</primary></indexterm>
	Many people ask why Samba cannot simply use the UNIX password database. Windows requires
	passwords that are encrypted in its own format.  The UNIX passwords can't be converted to 
	UNIX-style encrypted passwords. Because of that, you can't use the standard UNIX user
	database, and you have to store the LanMan and NT hashes somewhere else.
	</para>
	
	<para>
<indexterm><primary>differently encrypted passwords</primary></indexterm>
<indexterm><primary>profile</primary></indexterm>
<indexterm><primary>workstations</primary></indexterm>
<indexterm><primary>tdbsam</primary></indexterm>
	In addition to differently encrypted passwords, Windows also stores certain data for each
	user that is not stored in a UNIX user database: for example, workstations the user may logon from,
	the location where the user's profile is stored, and so on. Samba retrieves and stores this
	information using a <smbconfoption name="passdb backend"/>. Commonly available backends are LDAP,
	tdbsam, and plain text file. For more information, see the man page for &smb.conf; regarding the 
	<smbconfoption name="passdb backend"/> parameter.
	</para>


	<figure id="idmap-sid2uid">
		<title>IDMAP: Resolution of SIDs to UIDs.</title>
		<imagefile scale="40">idmap-sid2uid</imagefile>
	</figure>

	<para>
	<indexterm><primary>SID</primary></indexterm>
<indexterm><primary>UID</primary></indexterm>
<indexterm><primary>SID</primary></indexterm>
	The resolution of SIDs to UIDs is fundamental to correct operation of Samba. In both cases shown, if winbindd
	is not running or cannot be contacted, then only local SID/UID resolution is possible. See <link
	linkend="idmap-sid2uid">resolution of SIDs to UIDs</link> and <link linkend="idmap-uid2sid">resolution of UIDs
	to SIDs</link> diagrams.
	</para>

	<figure id="idmap-uid2sid">
		<title>IDMAP: Resolution of UIDs to SIDs.</title>
		<imagefile scale="50">idmap-uid2sid</imagefile>
	</figure>

	<sect2>
	<title>Important Notes About Security</title>
		
		<para>
<indexterm><primary>SMB password encryption</primary></indexterm>
<indexterm><primary>clear-text passwords</primary></indexterm>
<indexterm><primary>hashed password equivalent</primary></indexterm>
<indexterm><primary>LDAP</primary></indexterm>
<indexterm><primary>secret</primary></indexterm>
		The UNIX and SMB password encryption techniques seem similar on the surface. This
		similarity is, however, only skin deep. The UNIX scheme typically sends clear-text
		passwords over the network when logging in. This is bad. The SMB encryption scheme
		never sends the clear-text password over the network, but it does store the 16-byte 
		hashed values on disk. This is also bad. Why? Because the 16 byte hashed values
		are a <quote>password equivalent.</quote> You cannot derive the user's password from them, but
		they could potentially be used in a modified client to gain access to a server.
		This would require considerable technical knowledge on behalf of the attacker but
		is perfectly possible. You should therefore treat the data stored in whatever passdb
		backend you use (smbpasswd file, LDAP) as though it contained the clear-text
		passwords of all your users. Its contents must be kept secret, and the file should
		be protected accordingly.
		</para>
		
		<para>
<indexterm><primary>password scheme</primary></indexterm>
<indexterm><primary>plaintext passwords</primary></indexterm>
<indexterm><primary>compatible</primary></indexterm>
		Ideally, we would like a password scheme that involves neither plaintext passwords
		on the network nor plaintext passwords on disk. Unfortunately, this is not available because Samba is stuck with
		having to be compatible with other SMB systems (Windows NT, Windows for Workgroups, Windows 9x/Me).
		</para>

		<para>
<indexterm><primary>encrypted passwords</primary></indexterm>
<indexterm><primary>plaintext passwords</primary></indexterm>
		Windows NT 4.0 Service Pack 3 changed the default setting so plaintext passwords
		are disabled from being sent over the wire. This mandates either the use of encrypted
		password support or editing the Windows NT registry to re-enable plaintext passwords.
		</para>
		
		<para>
<indexterm><primary>domain security</primary></indexterm>
<indexterm><primary>domain environment</primary></indexterm>
		The following versions of Microsoft Windows do not support full domain security protocols,
		although they may log onto a domain environment:
		</para>

		<itemizedlist>
			<listitem><para>MS DOS Network client 3.0 with the basic network redirector installed.</para></listitem>
			<listitem><para>Windows 95 with the network redirector update installed.</para></listitem>
			<listitem><para>Windows 98 [Second Edition].</para></listitem>
			<listitem><para>Windows Me.</para></listitem>
		</itemizedlist>

		<note>
		<para>
<indexterm><primary>Windows XP Home</primary></indexterm>
<indexterm><primary>domain member</primary></indexterm>
<indexterm><primary>domain logons</primary></indexterm>
 		MS Windows XP Home does not have facilities to become a domain member, and it cannot participate in domain logons.
		</para>
		</note>

		<para>
		The following versions of MS Windows fully support domain security protocols.
		</para>

		<itemizedlist>
			<listitem><para>Windows NT 3.5x.</para></listitem>
			<listitem><para>Windows NT 4.0.</para></listitem>
			<listitem><para>Windows 2000 Professional.</para></listitem>
			<listitem><para>Windows 200x Server/Advanced Server.</para></listitem>
			<listitem><para>Windows XP Professional.</para></listitem>
		</itemizedlist>
			
		<para>
<indexterm><primary>SMB/CIFS</primary></indexterm>
<indexterm><primary>authentication</primary></indexterm>
<indexterm><primary>challenge/response mechanis</primary></indexterm>
<indexterm><primary>clear-text</primary></indexterm>
<indexterm><primary>encrypted</primary></indexterm>
<indexterm><primary>negotiate</primary></indexterm>
		All current releases of Microsoft SMB/CIFS clients support authentication via the
		SMB challenge/response mechanism described here. Enabling clear-text authentication
		does not disable the ability of the client to participate in encrypted authentication.
		Instead, it allows the client to negotiate either plaintext or encrypted password
		handling.
		</para>

		<para>
<indexterm><primary>cached encrypted password</primary></indexterm>
<indexterm><primary>plaintext passwords</primary></indexterm>
<indexterm><primary>registry change</primary></indexterm>
<indexterm><primary>auto-reconnect</primary></indexterm>
<indexterm><primary>encrypted passwords</primary></indexterm>
		MS Windows clients will cache the encrypted password alone. Where plaintext passwords
		are re-enabled through the appropriate registry change, the plaintext password is never
		cached. This means that in the event that a network connections should become disconnected
		(broken), only the cached (encrypted) password will be sent to the resource server to
		effect an auto-reconnect. If the resource server does not support encrypted passwords, the
		auto-reconnect will fail. Use of encrypted passwords is strongly advised.
		</para>

		<sect3>
		<title>Advantages of Encrypted Passwords</title>

			<itemizedlist>
				<listitem><para>
<indexterm><primary>passed across the network</primary></indexterm>
<indexterm><primary>network sniffer</primary></indexterm>
<indexterm><primary>SMB server</primary></indexterm>
				Plaintext passwords are not passed across the network. Someone using a network sniffer
				cannot just record passwords going to the SMB server.
				</para></listitem>

				<listitem><para>
<indexterm><primary>not stored anywhere</primary></indexterm>
<indexterm><primary>memory</primary></indexterm>
<indexterm><primary>disk</primary></indexterm>
				Plaintext passwords are not stored anywhere in memory or on disk.
				</para></listitem>
			 
				<listitem><para>
<indexterm><primary>encrypted passwords</primary></indexterm>
<indexterm><primary>user-level security</primary></indexterm>
<indexterm><primary>password prompt</primary></indexterm>
<indexterm><primary>SMB encryption</primary></indexterm>
				Windows NT does not like talking to a server that does not support encrypted passwords. It will refuse to
				browse the server if the server is also in user-level security mode. It will insist on prompting the user for
				the password on each connection, which is very annoying. The only thing you can do to stop this is to use SMB
				encryption.
				</para></listitem>

				<listitem><para>
<indexterm><primary>encrypted password</primary></indexterm>
<indexterm><primary>automatic reconnects</primary></indexterm>
				Encrypted password support allows automatic share (resource) reconnects.
				</para></listitem>

				<listitem><para>
<indexterm><primary>PDC</primary></indexterm>
<indexterm><primary>BDC</primary></indexterm>
				Encrypted passwords are essential for PDC/BDC operation.
				</para></listitem>
			</itemizedlist>
		</sect3>


		<sect3>
		<title>Advantages of Non-Encrypted Passwords</title>

			<itemizedlist>
				<listitem><para>
<indexterm><primary>cached in memory</primary></indexterm>
				Plaintext passwords are not kept on disk and are not cached in memory.
				</para></listitem>
				
				<listitem><para>
<indexterm><primary>Login</primary></indexterm>
<indexterm><primary>FTP</primary></indexterm>
				Plaintext passwords use the same password file as other UNIX services, such as Login and FTP.
				</para></listitem>
				
				<listitem><para>
<indexterm><primary>Telnet</primary></indexterm>
<indexterm><primary>FTP</primary></indexterm>
				Use of other services (such as Telnet and FTP) that send plaintext passwords over
				the network makes sending them for SMB not such a big deal.
				</para></listitem>
			</itemizedlist>
		</sect3>
	</sect2>

	<sect2>
	<title>Mapping User Identifiers between MS Windows and UNIX</title>

	<para>
<indexterm><primary>UID</primary></indexterm>
<indexterm><primary>SID</primary></indexterm>
<indexterm><primary>mapping</primary></indexterm>
	Every operation in UNIX/Linux requires a user identifier (UID), just as in
	MS Windows NT4/200x this requires a security identifier (SID). Samba provides
	two means for mapping an MS Windows user to a UNIX/Linux UID.
	</para>

	<para>
<indexterm><primary>Samba SAM</primary></indexterm>
<indexterm><primary>SAM</primary></indexterm>
<indexterm><primary>UID</primary></indexterm>
<indexterm><primary>account information database</primary></indexterm>
<indexterm><primary>local user account</primary></indexterm>
	First, all Samba SAM database accounts require a UNIX/Linux UID that the account will map to. As users are
	added to the account information database, Samba will call the <smbconfoption name="add user script"/>
	interface to add the account to the Samba host OS. In essence all accounts in the local SAM require a local
	user account.
	</para>

	<para>
	<indexterm><primary>idmap uid</primary></indexterm>
	<indexterm><primary>idmap gid</primary></indexterm>
	<indexterm><primary>UID</primary></indexterm>
	<indexterm><primary>SAM</primary></indexterm>
	<indexterm><primary>foreign domain</primary></indexterm>
	<indexterm><primary>non-member Windows client</primary></indexterm>
	<indexterm><primary>SID</primary></indexterm>
	The second way to map Windows SID to UNIX UID is via the <emphasis>idmap uid</emphasis> and
	<emphasis>idmap gid</emphasis> parameters in &smb.conf;.  Please refer to the man page for information about
	these parameters.  These parameters are essential when mapping users from a remote (non-member Windows client
	or a member of a foreign domain) SAM server.
	</para>

	</sect2>

	<sect2 id="idmapbackend">
	<title>Mapping Common UIDs/GIDs on Distributed Machines</title>

	<para>
<indexterm><primary>UID</primary></indexterm>
<indexterm><primary>GID</primary></indexterm>
<indexterm><primary>BDC</primary></indexterm>
<indexterm><primary>domain member servers</primary></indexterm>
<indexterm><primary>NFS</primary></indexterm>
<indexterm><primary>rsync</primary></indexterm>
	Samba-3 has a special facility that makes it possible to maintain identical UIDs and GIDs
	on all servers in a distributed network. A distributed network is one where there exists
	a PDC, one or more BDCs, and/or one or more domain member servers. Why is this important?
	This is important if files are being shared over more than one protocol (e.g., NFS) and where
	users are copying files across UNIX/Linux systems using tools such as <command>rsync</command>.
	</para>

	<para>
<indexterm><primary>LDAP-based</primary></indexterm>
<indexterm><primary>idmap backend</primary></indexterm>
<indexterm><primary>UID</primary></indexterm>
<indexterm><primary>GID</primary></indexterm>
<indexterm><primary>LDAP</primary></indexterm>
<indexterm><primary>SAM backend</primary></indexterm>
<indexterm><primary>LDAP idmap Backend</primary></indexterm>
	<indexterm><primary>idmap backend</primary></indexterm>
	The special facility is enabled using a parameter called <parameter>idmap backend</parameter>.
	The default setting for this parameter is an empty string. Technically it is possible to use
	an LDAP-based idmap backend for UIDs and GIDs, but it makes most sense when this is done for
	network configurations that also use LDAP for the SAM backend.
	<link linkend="idmapbackendexample">Example Configuration with the LDAP idmap Backend</link>
	shows that configuration.
	</para>

<indexterm><primary>SAM backend</primary><secondary>ldapsam</secondary></indexterm>
<example id="idmapbackendexample">
<title>Example Configuration with the LDAP idmap Backend</title>
<smbconfblock>
<smbconfsection name="[global]"/>
<smbconfoption name="idmap backend">ldap:ldap://ldap-server.quenya.org:636</smbconfoption>
<smbconfcomment>Alternatively, this could be specified as:</smbconfcomment>
<smbconfoption name="idmap backend">ldap:ldaps://ldap-server.quenya.org</smbconfoption>
</smbconfblock>
</example>

	<para>
<indexterm><primary>LDAP backends</primary></indexterm>
<indexterm><primary>PADL Software</primary></indexterm>
	A network administrator who wants to make significant use of LDAP backends will sooner or later be
	exposed to the excellent work done by PADL Software. PADL <ulink url="http://www.padl.com"/> have
	produced and released to open source an array of tools that might be of interest. These tools include:
	</para>

	<itemizedlist>
		<listitem>
		<para>
<indexterm><primary>nss_ldap</primary></indexterm>
<indexterm><primary>NSS</primary></indexterm>
<indexterm><primary>AIX</primary></indexterm>
<indexterm><primary>Linux</primary></indexterm>
<indexterm><primary>LDAP</primary></indexterm>
<indexterm><primary>Solaris</primary></indexterm>
<indexterm><primary>UID</primary></indexterm>
<indexterm><primary>GID</primary></indexterm>
		<emphasis>nss_ldap:</emphasis> An LDAP name service switch (NSS) module to provide native
		name service support for AIX, Linux, Solaris, and other operating systems. This tool
		can be used for centralized storage and retrieval of UIDs and GIDs.
		</para>
		</listitem>

		<listitem>
		<para>
<indexterm><primary>pam_ldap</primary></indexterm>
<indexterm><primary>PAM</primary></indexterm>
<indexterm><primary>LDAP</primary></indexterm>
<indexterm><primary>access authentication</primary></indexterm>
		<emphasis>pam_ldap:</emphasis> A PAM module that provides LDAP integration for UNIX/Linux
		system access authentication.
		</para>
		</listitem>

		<listitem>
		<para>
<indexterm><primary>idmap_ad</primary></indexterm>
<indexterm><primary>IDMAP backend</primary></indexterm>
<indexterm><primary>RFC 2307</primary></indexterm>
<indexterm><primary>PADL</primary></indexterm>
		<emphasis>idmap_ad:</emphasis> An IDMAP backend that supports the Microsoft Services for
		UNIX RFC 2307 schema available from the PADL Web 
		<ulink url="http://www.padl.com/download/xad_oss_plugins.tar.gz">site</ulink>.
		</para>
		</listitem>
	</itemizedlist>

	</sect2>

	<sect2>
	<title>Comments Regarding LDAP</title>

	<para>
<indexterm><primary>LDAP</primary><secondary>directories</secondary></indexterm>
<indexterm><primary>architecture</primary></indexterm>
<indexterm><primary>FIM</primary></indexterm>
<indexterm><primary>SSO</primary></indexterm>
	There is much excitement and interest in LDAP directories in the information technology world
	today. The LDAP architecture was designed to be highly scalable. It was also designed for
	use across a huge number of potential areas of application encompassing a wide range of operating
	systems and platforms. LDAP technologies are at the heart of the current generations of Federated
	Identity Management (FIM) solutions that can underlie a corporate Single Sign-On (SSO) environment.
	</para>

	<para>
<indexterm><primary>LDAP</primary></indexterm>
<indexterm><primary>eDirectory</primary></indexterm>
<indexterm><primary>ADS</primary></indexterm>
<indexterm><primary>authentication</primary></indexterm>
	LDAP implementations have been built across a wide variety of platforms. It lies at the core of Microsoft
	Windows Active Directory services (ADS), Novell's eDirectory, as well as many others. Implementation of the
	directory services LDAP involves interaction with legacy as well as new generation applications, all of which
	depend on some form of authentication services.
	</para>

	<para>
<indexterm><primary>LDAP directory</primary></indexterm>
<indexterm><primary>authentication</primary></indexterm>
<indexterm><primary>access controls</primary></indexterm>
<indexterm><primary>intermediate tools</primary></indexterm>
<indexterm><primary>middle-ware</primary></indexterm>
<indexterm><primary>central environment</primary></indexterm>
<indexterm><primary>infrastructure</primary></indexterm>
<indexterm><primary>login shells</primary></indexterm>
<indexterm><primary>mail</primary></indexterm>
<indexterm><primary>messaging systems</primary></indexterm>
<indexterm><primary>quota controls</primary></indexterm>
<indexterm><primary>printing systems</primary></indexterm>
<indexterm><primary>DNS servers</primary></indexterm>
<indexterm><primary>DHCP servers</primary></indexterm>
	UNIX services can utilize LDAP directory information for authentication and access controls
	through intermediate tools and utilities. The total environment that consists of the LDAP directory
	and the middle-ware tools and utilities makes it possible for all user access to the UNIX platform
	to be managed from a central environment and yet distributed to wherever the point of need may
	be physically located. Applications that benefit from this infrastructure include: UNIX login 
	shells, mail and messaging systems, quota controls, printing systems, DNS servers, DHCP servers,
	and also Samba.
	</para>

	<para>
<indexterm><primary>LDAP</primary></indexterm>
<indexterm><primary>passdb backend</primary></indexterm>
<indexterm><primary>scalable</primary></indexterm>
<indexterm><primary>SAM backend</primary></indexterm>
<indexterm><primary>LDAP directory</primary></indexterm>
<indexterm><primary>management costs</primary></indexterm>
	Many sites are installing LDAP for the first time in order to provide a scalable passdb backend
	for Samba. Others are faced with the need to adapt an existing LDAP directory to new uses such
	as for the Samba SAM backend. Whatever your particular need and attraction to Samba may be,
	decisions made in respect of the design of the LDAP directory structure and its implementation
	are of a durable nature for the site. These have far-reaching implications that affect long-term
	information systems management costs.
	</para>

	<para>
<indexterm><primary>LDAP deployment</primary></indexterm>
<indexterm><primary>Directory Information Tree</primary><see>DIT</see></indexterm>
	Do not rush into an LDAP deployment. Take the time to understand how the design of the Directory
	Information Tree (DIT) may impact current and future site needs, as well as the ability to meet
	them. The way that Samba SAM information should be stored within the DIT varies from site to site
	and with each implementation new experience is gained. It is well understood by LDAP veterans that
	first implementations create awakening, second implementations of LDAP create fear, and 
	third-generation deployments bring peace and tranquility.
	</para>

	<sect3>
	<title>Caution Regarding LDAP and Samba</title>

	<para>
<indexterm><primary>POSIX identity</primary></indexterm>
<indexterm><primary>networking environment</primary></indexterm>
<indexterm><primary>user accounts</primary></indexterm>
<indexterm><primary>group accounts</primary></indexterm>
<indexterm><primary>machine trust accounts</primary></indexterm>
<indexterm><primary>interdomain trust accounts</primary></indexterm>
<indexterm><primary>intermediate information</primary></indexterm>
	Samba requires UNIX POSIX identity information as well as a place to store information that is
	specific to Samba and the Windows networking environment. The most used information that must
	be dealt with includes: user accounts, group accounts, machine trust accounts, interdomain
	trust accounts, and intermediate information specific to Samba internals.
	</para>

	<para>
<indexterm><primary>deployment guidelines</primary></indexterm>
<indexterm><primary>HOWTO documents</primary></indexterm>
<indexterm><primary>LDAP</primary></indexterm>
	The example deployment guidelines in this book, as well as other books and HOWTO documents
	available from the internet may not fit with established directory designs and implementations.
	The existing DIT may not be able to accommodate the simple information layout proposed in common
	sources. Additionally, you may find that the common scripts and tools that are used to provision
	the LDAP directory for use with Samba may not suit your needs.
	</para>

	<para>
<indexterm><primary>existing LDAP DIT</primary></indexterm>
	It is not uncommon, for sites that have existing LDAP DITs to find necessity to generate a
	set of site-specific scripts and utilities to make it possible to deploy Samba within the
	scope of site operations. The way that user and group accounts are distributed throughout
	the DIT may make this a challenging matter. The solution will, of course, be rewarding, but
	the journey to it may be challenging. Take time to understand site needs and do not rush
	into deployment.
	</para>

	<para>
<indexterm><primary>scripts</primary></indexterm>
<indexterm><primary>tools</primary></indexterm>
	Above all, do not blindly use scripts and tools that are not suitable for your site. Check
	and validate all scripts before you execute them to make sure that the existing infrastructure
	will not be damaged by inadvertent use of an inappropriate tool.
	</para>

	</sect3>

	</sect2>

	<sect2>
	<title>LDAP Directories and Windows Computer Accounts</title>

		<para>
<indexterm><primary>turnkey solution</primary></indexterm>
<indexterm><primary>LDAP.</primary></indexterm>
<indexterm><primary>frustrating experience</primary></indexterm>
		Samba doesn't provide a turnkey solution to LDAP. It is best to deal with the design and
		configuration of an LDAP directory prior to integration with Samba. A working knowledge
		of LDAP makes Samba integration easy, and the lack of a working knowledge of LDAP can make
		it a frustrating experience.
		</para>

		<para>
<indexterm><primary>computer accounts</primary></indexterm>
<indexterm><primary>machine accounts</primary></indexterm>
<indexterm><primary>LDAP</primary></indexterm>
		Computer (machine) accounts can be placed wherever you like in an LDAP directory subject
		to some constraints that are described in this chapter.
		</para>

		<para>
<indexterm><primary>POSIX</primary></indexterm>
<indexterm><primary>sambaSamAccount</primary></indexterm>
<indexterm><primary>computer accounts</primary></indexterm>
<indexterm><primary>machine accounts</primary></indexterm>
<indexterm><primary>Windows NT4/200X</primary></indexterm>
<indexterm><primary>user account</primary></indexterm>
<indexterm><primary>trust accounts</primary></indexterm>
		The POSIX and sambaSamAccount components of computer (machine) accounts are both used by Samba.
		Thus, machine accounts are treated inside Samba in the same way that Windows NT4/200X treats
		them. A user account and a machine account are indistinquishable from each other, except that
		the machine account ends in a $ character, as do trust accounts.
		</para>

		<para>
<indexterm><primary>user</primary></indexterm>
<indexterm><primary>group</primary></indexterm>
<indexterm><primary>machine</primary></indexterm>
<indexterm><primary>trust</primary></indexterm>
<indexterm><primary>UID</primary></indexterm>
		The need for Windows user, group, machine, trust, and other accounts to be tied to a valid UNIX
		UID is a design decision that was made a long way back in the history of Samba development. It
		is unlikely that this decision will be reversed or changed during the remaining life of the
		Samba-3.x series.
		</para>

		<para>
<indexterm><primary>UID</primary></indexterm>
<indexterm><primary>SID</primary></indexterm>
<indexterm><primary>NSS</primary></indexterm>
		The resolution of a UID from the Windows SID is achieved within Samba through a mechanism that
		must refer back to the host operating system on which Samba is running. The NSS is the preferred
		mechanism that shields applications (like Samba) from the need to know everything about every
		host OS it runs on.
		</para>

		<para>
<indexterm><primary>UID</primary></indexterm>
<indexterm><primary>passwd</primary></indexterm>
<indexterm><primary>shadow</primary></indexterm>
<indexterm><primary>group</primary></indexterm>
<indexterm><primary>NSS</primary></indexterm>
<indexterm><primary>winbindd</primary></indexterm>
<indexterm><primary>LDAP</primary></indexterm>
		Samba asks the host OS to provide a UID via the <quote>passwd</quote>, <quote>shadow</quote>,
		and <quote>group</quote> facilities in the NSS control (configuration) file. The best tool
		for achieving this is left up to the UNIX administrator to determine. It is not imposed by
		Samba. Samba provides winbindd with its support libraries as one method. It is
		possible to do this via LDAP, and for that Samba provides the appropriate hooks so that
		all account entities can be located in an LDAP directory.
		</para>

		<para>
<indexterm><primary>PADL</primary></indexterm>
<indexterm><primary>nss_ldap</primary></indexterm>
<indexterm><primary>UID</primary></indexterm>
<indexterm><primary>LDAP</primary></indexterm>
<indexterm><primary>documentation</primary></indexterm>
		For many the weapon of choice is to use the PADL nss_ldap utility. This utility must
		be configured so that computer accounts can be resolved to a POSIX/UNIX account UID. That
		is fundamentally an LDAP design question.  The information provided on the Samba list and
		in the documentation is directed at providing working examples only. The design
		of an LDAP directory is a complex subject that is beyond the scope of this documentation.
		</para>

	</sect2>

</sect1>

<sect1 id="acctmgmttools">
<title>Account Management Tools</title>

<para>
<indexterm><primary>pdbedit</primary></indexterm>
<indexterm><primary>machine accounts</primary></indexterm>
<indexterm><primary>management tools</primary></indexterm>
Samba provides two tools for management of user and machine accounts:
<command>smbpasswd</command> and <command>pdbedit</command>. 
</para>

<para>
<indexterm><primary>pdbedit</primary></indexterm>
<indexterm><primary>password aging</primary></indexterm>
<indexterm><primary>failed logins</primary></indexterm>
The <command>pdbedit</command> can be used to manage account policies in addition to
Samba user account information. The policy management capability is used to administer
domain default settings for password aging and management controls to handle failed login
attempts.
</para>

<para>
<indexterm><primary>smbpasswd</primary></indexterm>
<indexterm><primary>storage mechanism</primary></indexterm>
<indexterm><primary>SambaSAMAccount</primary></indexterm>
<indexterm><primary>net</primary></indexterm>
Some people are confused when reference is made to <literal>smbpasswd</literal> because the
name refers to a storage mechanism for SambaSAMAccount information, but it is also the name
of a utility tool. That tool is destined to eventually be replaced by new functionality that
is being added to the <command>net</command> toolset (see <link linkend="NetCommand">the Net Command</link>.
</para>

	<sect2>
	<title>The <command>smbpasswd</command> Tool</title>
	
		<para>
<indexterm><primary>smbpasswd</primary></indexterm>
<indexterm><primary>passwd</primary></indexterm>
<indexterm><primary>yppasswd</primary></indexterm>
<indexterm><primary>passdb backend</primary></indexterm>
<indexterm><primary>storage methods</primary></indexterm>
		The <command>smbpasswd</command> utility is similar to the <command>passwd</command>
		and <command>yppasswd</command> programs. It maintains the two 32 byte password
		fields in the passdb backend. This utility operates independently of the actual
		account and password storage methods used (as specified by the <parameter>passdb
		backend</parameter> in the &smb.conf; file.
		</para>

		<para>
<indexterm><primary>smbpasswd</primary></indexterm>
<indexterm><primary>client-server mode</primary></indexterm>
		<command>smbpasswd</command> works in a client-server mode where it contacts the
		local smbd to change the user's password on its behalf. This has enormous benefits.
		</para>

		<para>
<indexterm><primary>smbpasswd</primary></indexterm>
<indexterm><primary>change passwords</primary></indexterm>
		<command>smbpasswd</command> has the capability to change passwords on Windows NT
		servers (this only works when the request is sent to the NT PDC if changing an NT
		domain user's password).
		</para>

		<para>
		<indexterm><primary>user management</primary></indexterm>
		<indexterm><primary>user account</primary><secondary>Adding/Deleting</secondary></indexterm>
		<command>smbpasswd</command> can be used to:
		</para>

		<itemizedlist>
			<listitem><para><emphasis>add</emphasis> user or machine accounts.</para></listitem>
			<listitem><para><emphasis>delete</emphasis> user or machine accounts.</para></listitem>
			<listitem><para><emphasis>enable</emphasis> user or machine accounts.</para></listitem>
			<listitem><para><emphasis>disable</emphasis> user or machine accounts.</para></listitem>
			<listitem><para><emphasis>set to NULL</emphasis> user passwords.</para></listitem>
			<listitem><para><emphasis>manage</emphasis> interdomain trust accounts.</para></listitem>
		</itemizedlist>
		
		<para>
		To run smbpasswd as a normal user, just type:
		</para>
		
		<para>
<screen>
&prompt;<userinput>smbpasswd</userinput>
<prompt>Old SMB password: </prompt><userinput><replaceable>secret</replaceable></userinput>
</screen>
		For <replaceable>secret</replaceable>, type the old value here or press return if
		there is no old password.
<screen>
<prompt>New SMB Password: </prompt><userinput><replaceable>new secret</replaceable></userinput>
<prompt>Repeat New SMB Password: </prompt><userinput><replaceable>new secret</replaceable></userinput>
</screen>
		</para>
		
		<para>
		If the old value does not match the current value stored for that user, or the two
		new values do not match each other, then the password will not be changed.
		</para>
		
		<para>
<indexterm><primary>SMB password</primary></indexterm>
		When invoked by an ordinary user, the command will allow only the user to change his or her own
		SMB password.
		</para>
		
		<para>
<indexterm><primary>smbpasswd</primary></indexterm>
<indexterm><primary>SMB password</primary></indexterm>
		When run by root, <command>smbpasswd</command> may take an optional argument specifying
		the username whose SMB password you wish to change. When run as root, <command>smbpasswd</command>
		does not prompt for or check the old password value, thus allowing root to set passwords 
		for users who have forgotten their passwords.
		</para>
		
		<para>
<indexterm><primary>smbpasswd</primary></indexterm>
<indexterm><primary>passwd</primary></indexterm>
<indexterm><primary>yppasswd</primary></indexterm>
<indexterm><primary>change capabilities</primary></indexterm>
		<command>smbpasswd</command> is designed to work in the way familiar to UNIX
		users who use the <command>passwd</command> or <command>yppasswd</command> commands.
		While designed for administrative use, this tool provides essential user-level
		password change capabilities.
		</para>

		<para>
<indexterm><primary>smbpasswd</primary></indexterm>
		For more details on using <command>smbpasswd</command>, refer to the man page (the
		definitive reference).
		</para>
	</sect2>

	<sect2 id="pdbeditthing">
	<title>The <command>pdbedit</command> Tool</title>

		<para>
		<indexterm><primary>pdbedit</primary></indexterm>
		<indexterm><primary>User Management</primary></indexterm>
		<indexterm><primary>account policy</primary></indexterm>
		<indexterm><primary>User Accounts</primary><secondary>Adding/Deleting</secondary></indexterm>
		<command>pdbedit</command> is a tool that can be used only by root. It is used to
		manage the passdb backend, as well as domain-wide account policy settings. <command>pdbedit</command> 
		can be used to:
		</para>

		<itemizedlist>
			<listitem><para>add, remove, or modify user accounts.</para></listitem>
			<listitem><para>list user accounts.</para></listitem>
			<listitem><para>migrate user accounts.</para></listitem>
			<listitem><para>migrate group accounts.</para></listitem>
			<listitem><para>manage account policies.</para></listitem>
			<listitem><para>manage domain access policy settings.</para></listitem>
		</itemizedlist>

		<para>
		<indexterm><primary>Sarbanes-Oxley</primary></indexterm>
		Under the terms of the Sarbanes-Oxley Act of 2002, American businesses and organizations are mandated to
		implement a series of <literal>internal controls</literal> and procedures to communicate, store,
		and protect financial data. The Sarbanes-Oxley Act has far reaching implications in respect of:
		</para>

		<orderedlist>
			<listitem><para>Who has access to information systems that store financial data.</para></listitem>
			<listitem><para>How personal and financial information is treated among employees and business
				partners.</para></listitem>
			<listitem><para>How security vulnerabilities are managed.</para></listitem>
			<listitem><para>Security and patch level maintenance for all information systems.</para></listitem>
			<listitem><para>How information systems changes are documented and tracked.</para></listitem>
			<listitem><para>How information access controls are implemented and managed.</para></listitem>
			<listitem><para>Auditability of all information systems in respect of change and security.</para></listitem>
			<listitem><para>Disciplinary procedures and controls to ensure privacy.</para></listitem>
		</orderedlist>

		<para>
		<indexterm><primary>accountability</primary></indexterm>
		<indexterm><primary>compliance</primary></indexterm>
		In short, the Sarbanes-Oxley Act of 2002 is an instrument that enforces accountability in respect of
		business related information systems so as to ensure the compliance of all information systems that
		are used to store personal information and particularly for financial records processing. Similar
		accountabilities are being demanded around the world.
		</para>

		<para>
		<indexterm><primary>laws</primary></indexterm>
		<indexterm><primary>regulations</primary></indexterm>
		<indexterm><primary>pdbedit</primary></indexterm>
		<indexterm><primary>access controls</primary></indexterm>
		<indexterm><primary>manage accounts</primary></indexterm>
		The need to be familiar with the Samba tools and facilities that permit information systems operation
		in compliance with government laws and regulations is clear to all. The <command>pdbedit</command> is
		currently the only Samba tool that provides the capacity to manage account and systems access controls
		and policies. During the remaining life-cycle of the Samba-3 series it is possible the new tools may
		be implemented to aid in this important area.
		</para>

		<para>
		Domain global policy controls available in Windows NT4 compared with Samba
		is shown in <link linkend="policycontrols">NT4 Domain v's Samba Policy Controls</link>.
		</para>

		<table id="policycontrols">
		<title>NT4 Domain v's Samba Policy Controls</title>
            <tgroup cols="5">
                <colspec align="left" colwidth="2*"/>
                <colspec align="left" colwidth="2*"/>
                <colspec align="center" colwidth="1*"/>
                <colspec align="center" colwidth="1*"/>
                <colspec align="center" colwidth="1*"/>
                <thead>
                    <row>
                        <entry><para>NT4 policy Name</para></entry>
                        <entry><para>Samba Policy Name</para></entry>
                        <entry><para>NT4 Range</para></entry>
                        <entry><para>Samba Range</para></entry>
                        <entry><para>Samba Default</para></entry>
                    </row>
                </thead>
                <tbody>
                    <row>
					<entry><para>Maximum Password Age</para></entry>
					<entry><para>maximum password age</para></entry>
					<entry><para>0 - 999 (days)</para></entry>
					<entry><para>0 - 4294967295 (sec)</para></entry>
					<entry><para>4294967295</para></entry>
                    </row>
                    <row>
					<entry><para>Minimum Password Age</para></entry>
					<entry><para>minimum password age</para></entry>
					<entry><para>0 - 999 (days)</para></entry>
					<entry><para>0 - 4294967295 (sec)</para></entry>
					<entry><para>0</para></entry>
                    </row>
                    <row>
					<entry><para>Mimimum Password Length</para></entry>
					<entry><para>min password length</para></entry>
					<entry><para>1 - 14 (Chars)</para></entry>
					<entry><para>0 - 4294967295 (Chars)</para></entry>
					<entry><para>5</para></entry>
                    </row>
                    <row>
					<entry><para>Password Uniqueness</para></entry>
					<entry><para>password history</para></entry>
					<entry><para>0 - 23 (#)</para></entry>
					<entry><para>0 - 4294967295 (#)</para></entry>
					<entry><para>0</para></entry>
                    </row>
                    <row>
					<entry><para>Account Lockout - Reset count after</para></entry>
					<entry><para>reset count minutes</para></entry>
					<entry><para>1 - 99998 (min)</para></entry>
					<entry><para>0 - 4294967295 (min)</para></entry>
					<entry><para>30</para></entry>
                    </row>
                    <row>
					<entry><para>Lockout after bad logon attempts</para></entry>
					<entry><para>bad lockout attempt</para></entry>
					<entry><para>0 - 998 (#)</para></entry>
					<entry><para>0 - 4294967295 (#)</para></entry>
					<entry><para>0</para></entry>
                    </row>
                    <row>
					<entry><para>*** Not Known ***</para></entry>
					<entry><para>disconnect time</para></entry>
					<entry><para>TBA</para></entry>
					<entry><para>0 - 4294967295</para></entry>
					<entry><para>0</para></entry>
                    </row>
                    <row>
					<entry><para>Lockout Duration</para></entry>
					<entry><para>lockout duration</para></entry>
					<entry><para>1 - 99998 (min)</para></entry>
					<entry><para>0 - 4294967295 (min)</para></entry>
					<entry><para>30</para></entry>
                    </row>
                    <row>
					<entry><para>Users must log on in order to change password</para></entry>
					<entry><para>user must logon to change password</para></entry>
					<entry><para>0/1</para></entry>
					<entry><para>0 - 4294967295</para></entry>
					<entry><para>0</para></entry>
                    </row>
                    <row>
					<entry><para>*** Registry Setting ***</para></entry>
					<entry><para>refuse machine password change</para></entry>
					<entry><para>0/1</para></entry>
					<entry><para>0 - 4294967295</para></entry>
					<entry><para>0</para></entry>
                    </row>
				</tbody>
			</tgroup>
		</table>

		<para>
		<indexterm><primary>pdbedit</primary></indexterm>
<indexterm><primary>policy settings</primary></indexterm>
<indexterm><primary>account security</primary></indexterm>
<indexterm><primary>smbpasswd</primary></indexterm>
		The <command>pdbedit</command> tool is the only one that can manage the account
		security and policy settings. It is capable of all operations that smbpasswd can
		do as well as a superset of them.
		</para>

		<para>
		<indexterm><primary>pdbedit</primary></indexterm>
<indexterm><primary>account migration</primary></indexterm>
<indexterm><primary>passdb backend</primary></indexterm>
		One particularly important purpose of the <command>pdbedit</command> is to allow
		the migration of account information from one passdb backend to another. 
		</para>

		<sect3>
		<title>User Account Management</title>

		<para>
<indexterm><primary>pdbedit</primary></indexterm>
<indexterm><primary>smbpasswd</primary></indexterm>
<indexterm><primary>system accounts</primary></indexterm>
<indexterm><primary>user account</primary></indexterm>
<indexterm><primary>domain user manager</primary></indexterm>
<indexterm><primary>add user script</primary></indexterm>
<indexterm><primary>interface scripts</primary></indexterm>
		The <command>pdbedit</command> tool, like the <command>smbpasswd</command> tool, requires
		that a POSIX user account already exists in the UNIX/Linux system accounts database (backend).
		Neither tool will call out to the operating system to create a user account because this is
		considered to be the responsibility of the system administrator. When the Windows NT4 domain
		user manager is used to add an account, Samba will implement the <literal>add user script</literal>
		(as well as the other interface scripts) to ensure that user, group and machine accounts are
		correctly created and changed. The use of the <command>pdbedit</command> tool does not
		make use of these interface scripts.
		</para>

		<para>
<indexterm><primary>pdbedit</primary></indexterm>
<indexterm><primary>POSIX account</primary></indexterm>
		Before attempting to use the <command>pdbedit</command> tool to manage user and machine
		accounts, make certain that a system (POSIX) account has already been created.
		</para>

		<sect4>
		<title>Listing User and Machine Accounts</title>

		<para>
<indexterm><primary>tdbsam</primary></indexterm>
<indexterm><primary>password backend</primary></indexterm>
		The following is an example of the user account information that is stored in
		a tdbsam password backend. This listing was produced by running:
<screen>
&prompt;<userinput>pdbedit -Lv met</userinput>
UNIX username:        met
NT username:          met
Account Flags:        [U          ]
User SID:             S-1-5-21-1449123459-1407424037-3116680435-2004
Primary Group SID:    S-1-5-21-1449123459-1407424037-3116680435-1201
Full Name:            Melissa E Terpstra
Home Directory:       \\frodo\met\Win9Profile
HomeDir Drive:        H:
Logon Script:         scripts\logon.bat
Profile Path:         \\frodo\Profiles\met
Domain:               &example.workgroup;
Account desc:
Workstations:         melbelle
Munged dial:
Logon time:           0
Logoff time:          Mon, 18 Jan 2038 20:14:07 GMT
Kickoff time:         Mon, 18 Jan 2038 20:14:07 GMT
Password last set:    Sat, 14 Dec 2002 14:37:03 GMT
Password can change:  Sat, 14 Dec 2002 14:37:03 GMT
Password must change: Mon, 18 Jan 2038 20:14:07 GMT
</screen>
		</para>

		<para>
<indexterm><primary>smbpasswd format</primary></indexterm>
		Accounts can also be listed in the older <literal>smbpasswd</literal> format:
<screen>
&rootprompt;<userinput>pdbedit -Lw</userinput>
root:0:84B0D8E14D158FF8417EAF50CFAC29C3:
     AF6DD3FD4E2EA8BDE1695A3F05EFBF52:[U          ]:LCT-42681AB8:
jht:1000:6BBC4159020A52741486235A2333E4D2:
     CC099521AD554A3C3CF2556274DBCFBC:[U          ]:LCT-40D75B5B:
rcg:1002:E95D4331A6F23AF8AAD3B435B51404EE:
     BB0F2C39B04CA6100F0E535DF8314B43:[U          ]:LCT-40D7C5A3:
afw:1003:1AAFA7F9F6DC1DEAAAD3B435B51404EE:
     CE92C2F9471594CDC4E7860CA6BC62DB:[T          ]:LCT-40DA501F:
met:1004:A2848CB7E076B435AAD3B435B51404EE:
     F25F5D3405085C555236B80B7B22C0D2:[U          ]:LCT-4244FAB8:
aurora$:1005:060DE593EA638B8ACC4A19F14D2FF2BB:
     060DE593EA638B8ACC4A19F14D2FF2BB:[W          ]:LCT-4173E5CC:
temptation$:1006:XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX:
     A96703C014E404E33D4049F706C45EE9:[W          ]:LCT-42BF0C57:
vaioboss$:1001:XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX:
     88A30A095160072784C88F811E89F98A:[W          ]:LCT-41C3878D:
frodo$:1008:15891DC6B843ECA41249940C814E316B:
     B68EADCCD18E17503D3DAD3E6B0B9A75:[W          ]:LCT-42B7979F:
marvel$:1011:BF709959C3C94E0B3958B7B84A3BB6F3:
     C610EFE9A385A3E8AA46ADFD576E6881:[W          ]:LCT-40F07A4
</screen>
<indexterm><primary>login id</primary></indexterm>
<indexterm><primary>UID</primary></indexterm>
<indexterm><primary>LanManger password</primary></indexterm>
<indexterm><primary>NT password</primary></indexterm>
<indexterm><primary>Account Flags</primary></indexterm>
<indexterm><primary>LCT</primary><see>last change time</see></indexterm>
		The account information that was returned by this command in order from left to right 
		consists of the following colon separated data:
		</para>

		<itemizedlist>
			<listitem><para>Login ID.</para></listitem>
			<listitem><para>UNIX UID.</para></listitem>
			<listitem>
				<para>Microsoft LanManager password hash (password converted to upper-case then hashed.</para>
			</listitem>
			<listitem><para>Microsoft NT password hash (hash of the case-preserved password).</para></listitem>
			<listitem><para>Samba SAM Account Flags.</para></listitem>
			<listitem><para>The LCT data (password last change time).</para></listitem>
		</itemizedlist>

		<para>
<indexterm><primary>Account Flags</primary></indexterm>
<indexterm><primary>pdbedit</primary></indexterm>
		The Account Flags parameters are documented in the <command>pdbedit</command> man page, and are
		briefly documented in <link linkend="TOSHARG-acctflags">the Account Flags Management section</link>.
		</para>

		<para>
<indexterm><primary>last change time</primary></indexterm>
		The LCT data consists of 8 hexadecimal characters representing the time since January 1, 1970, of
		the time when the password was last changed.
		</para>

		</sect4>

		<sect4>
		<title>Adding User Accounts</title>

		<para>
<indexterm><primary>pdbedit</primary></indexterm>
<indexterm><primary>add a user account</primary></indexterm>
<indexterm><primary>standalone server</primary></indexterm>
<indexterm><primary>domain</primary></indexterm>
<indexterm><primary>SambaSAMAccount</primary></indexterm>
		The <command>pdbedit</command> can be used to add a user account to a standalone server
		or to a domain. In the example shown here the account for the user <literal>vlaan</literal>
		has been created before attempting to add the SambaSAMAccount.
<screen>
&rootprompt; pdbedit -a vlaan
new password: secretpw
retype new password: secretpw
Unix username:        vlaan
NT username:          vlaan
Account Flags:        [U          ]
User SID:             S-1-5-21-726309263-4128913605-1168186429-3014
Primary Group SID:    S-1-5-21-726309263-4128913605-1168186429-513
Full Name:            Victor Laan
Home Directory:       \\frodo\vlaan
HomeDir Drive:        H:
Logon Script:         scripts\logon.bat
Profile Path:         \\frodo\profiles\vlaan
Domain:               &example.workgroup;
Account desc:         Guest User
Workstations:
Munged dial:
Logon time:           0
Logoff time:          Mon, 18 Jan 2038 20:14:07 GMT
Kickoff time:         Mon, 18 Jan 2038 20:14:07 GMT
Password last set:    Wed, 29 Jun 2005 19:35:12 GMT
Password can change:  Wed, 29 Jun 2005 19:35:12 GMT
Password must change: Mon, 18 Jan 2038 20:14:07 GMT
Last bad password   : 0
Bad password count  : 0
Logon hours         : FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
</screen>
		</para>

		</sect4>

		<sect4>
		<title>Deleting Accounts</title>

		<para>
<indexterm><primary>account deleted</primary></indexterm>
<indexterm><primary>SambaSAMAccount</primary></indexterm>
<indexterm><primary>pdbedit</primary></indexterm>
<indexterm><primary>passdb backend</primary></indexterm>
		An account can be deleted from the SambaSAMAccount database
<screen>
&rootprompt; pdbedit -x vlaan
</screen>
		The account is removed without further screen output. The account is removed only from the
		SambaSAMAccount (passdb backend) database, it is not removed from the UNIX account backend.
		</para>

		<para>
<indexterm><primary>delete user script</primary></indexterm>
<indexterm><primary>pdbedit</primary></indexterm>
		The use of the NT4 domain user manager to delete an account will trigger the <parameter>delete user
		script</parameter>, but not the <command>pdbedit</command> tool.
		</para>

		</sect4>

		<sect4>
		<title>Changing User Accounts</title>

		<para>
<indexterm><primary>pdbedit</primary></indexterm>
		Refer to the <command>pdbedit</command> man page for a full synopsis of all operations
		that are available with this tool.
		</para>

		<para>
<indexterm><primary>pdbedit</primary></indexterm>
		An example of a simple change in the user account information is the change of the full name
		information shown here:
<screen>
&rootprompt; pdbedit -r --fullname="Victor Aluicious Laan" vlaan
...
Primary Group SID:    S-1-5-21-726309263-4128913605-1168186429-513
Full Name:            Victor Aluicious Laan
Home Directory:       \\frodo\vlaan
...
</screen>
		</para>

		<para>
<indexterm><primary>grace time</primary></indexterm>
<indexterm><primary>password expired</primary></indexterm>
<indexterm><primary>expired password</primary></indexterm>
		Let us assume for a moment that a user's password has expired and the user is unable to
		change the password at this time. It may be necessary to give the user additional grace time
		so that it is possible to continue to work with the account and the original password. This
		demonstrates how the password expiration settings may be updated
<screen>
&rootprompt; pdbedit -Lv vlaan
...
Password last set:    Sun, 09 Sep 2001 22:21:40 GMT
Password can change:  Thu, 03 Jan 2002 15:08:35 GMT
Password must change: Thu, 03 Jan 2002 15:08:35 GMT
Last bad password   : Thu, 03 Jan 2002 15:08:35 GMT
Bad password count  : 2
...
</screen>
<indexterm><primary>bad logon attempts</primary></indexterm>
<indexterm><primary>lock the account</primary></indexterm>
		The user has recorded 2 bad logon attempts and the next will lock the account, but the
		password is also expired. Here is how this account can be reset:
<screen>
&rootprompt; pdbedit -z vlaan
...
Password last set:    Sun, 09 Sep 2001 22:21:40 GMT
Password can change:  Thu, 03 Jan 2002 15:08:35 GMT
Password must change: Thu, 03 Jan 2002 15:08:35 GMT
Last bad password   : 0
Bad password count  : 0
...
</screen>
		The <literal>Password must change:</literal> parameter can be reset like this:
<screen>
&rootprompt; pdbedit --pwd-must-change-time=1200000000 vlaan
...
Password last set:    Sun, 09 Sep 2001 22:21:40 GMT
Password can change:  Thu, 03 Jan 2002 15:08:35 GMT
Password must change: Thu, 10 Jan 2008 14:20:00 GMT
...
</screen>
		Another way to use this tools is to set the date like this:
<screen>
&rootprompt; pdbedit --pwd-must-change-time="2010-01-01" \
              --time-format="%Y-%m-%d" vlaan
...
Password last set:    Sun, 09 Sep 2001 22:21:40 GMT
Password can change:  Thu, 03 Jan 2002 15:08:35 GMT
Password must change: Fri, 01 Jan 2010 00:00:00 GMT
...
</screen>
<indexterm><primary>strptime</primary></indexterm>
<indexterm><primary>time format</primary></indexterm>
		Refer to the strptime man page for specific time format information.
		</para>

		<para>
<indexterm><primary>pdbedit</primary></indexterm>
<indexterm><primary>SambaSAMAccount</primary></indexterm>
		Please refer to the pdbedit man page for further information relating to SambaSAMAccount
		management.
		</para>

		<sect5 id="TOSHARG-acctflags">
		<title>Account Flags Management</title>

		<para>
<indexterm><primary>Samba SAM account flags</primary></indexterm>
<indexterm><primary>account control block</primary><see>ACB</see></indexterm>
<indexterm><primary>account encode_bits</primary></indexterm>
<indexterm><primary>account control flags</primary></indexterm>
		The Samba SAM account flags are properly called the ACB (account control block) within
		the Samba source code. In some parts of the Samba source code they are referred to as the 
		account encode_bits, and also as the account control flags.
		</para>

		<para>
<indexterm><primary>pdbedit</primary></indexterm>
<indexterm><primary>user account</primary></indexterm>
<indexterm><primary>machine account</primary></indexterm>
<indexterm><primary>trust account</primary></indexterm>
<indexterm><primary>damaged data</primary></indexterm>
		The manual adjustment of user, machine (workstation or server) or an inter-domain trust
		account account flgas should not be necessary under normal conditions of use of Samba. On the other hand,
		where this information becomes corrupted for some reason, the ability to correct the damaged data is certainly
		useful. The tool of choice by which such correction can be affected is the <command>pdbedit</command> utility.
		</para>

		<para>
<indexterm><primary>account flags</primary></indexterm>
<indexterm><primary>LDAP directory</primary></indexterm>
		There have been a few requests for information regarding the account flags from developers
		who are creating their own Samba management tools. An example of a need for information regarding
		the proper management of the account flags is evident when developing scripts that will be used
		to manage an LDAP directory.
		</para>

		<para>
<indexterm><primary>pdbedit</primary></indexterm>
<indexterm><primary>account flag order</primary></indexterm>
		The account flag field can contain up to 16 characters. Presently, only 11 are in use.
		These are listed in <link linkend="accountflags">Samba SAM Account Control Block Flags</link>.
		The order in which the flags are specified to the <command>pdbedit</command> command is not important.
		In fact, they can be set without problem in any order in the SambaAcctFlags record in the LDAP directory.
		</para>

		<table frame="all" id="accountflags">
		<title>Samba SAM Account Control Block Flags</title>
        <tgroup cols="2" align="center">
            <thead>
            <row><entry align="center">Flag</entry><entry>Description</entry></row>
            </thead>
            <tbody>
            <row>
				<entry align="center">D</entry>
				<entry align="left">Account is disabled.</entry>
			</row>
            <row>
				<entry align="center">H</entry>
				<entry align="left">A home directory is required.</entry>
			</row>
            <row>
				<entry align="center">I</entry>
				<entry align="left">An inter-domain trust account.</entry>
			</row>
            <row>
				<entry align="center">L</entry>
				<entry align="left">Account has been auto-locked.</entry>
			</row>
            <row>
				<entry align="center">M</entry>
				<entry align="left">An MNS (Microsoft network service) logon account.</entry>
			</row>
            <row>
				<entry align="center">N</entry>
				<entry align="left">Password not required.</entry>
			</row>
            <row>
				<entry align="center">S</entry>
				<entry align="left">A server trust account.</entry>
			</row>
            <row>
				<entry align="center">T</entry>
				<entry align="left">Temporary duplicate account entry.</entry>
			</row>
            <row>
				<entry align="center">U</entry>
				<entry align="left">A normal user account.</entry>
			</row>
            <row>
				<entry align="center">W</entry>
				<entry align="left">A workstation trust account.</entry>
			</row>
            <row>
				<entry align="center">X</entry>
				<entry align="left">Password does not expire.</entry>
			</row>
            </tbody>
        </tgroup>
        </table>

		<para>
<indexterm><primary>pdbedit</primary></indexterm>
<indexterm><primary>account control flags</primary></indexterm>
		An example of use of the <command>pdbedit</command> utility to set the account control flags
		is shown here:
<screen>
&rootprompt; pdbedit -r -c "[DLX]" jra
Unix username:        jht
NT username:          jht
Account Flags:        [DHULX      ]
User SID:             S-1-5-21-729263-4123605-1186429-3000
Primary Group SID:    S-1-5-21-729263-4123605-1186429-513
Full Name:            John H Terpstra,Utah Office
Home Directory:       \\aurora\jht
HomeDir Drive:        H:
Logon Script:         scripts\logon.bat
Profile Path:         \\aurora\profiles\jht
Domain:               MIDEARTH
Account desc:         BluntObject
Workstations:
Logon time:           0
Logoff time:          Mon, 18 Jan 2038 20:14:07 GMT
Kickoff time:         0
Password last set:    Sun, 03 Jul 2005 23:19:18 GMT
Password can change:  Sun, 03 Jul 2005 23:19:18 GMT
Password must change: Mon, 18 Jan 2038 20:14:07 GMT
Last bad password   : 0
Bad password count  : 0
Logon hours         : FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
</screen>
<indexterm><primary>default settings</primary></indexterm>
	The flags can be reset to the default settings by executing:
<screen>
&rootprompt; pdbedit -r -c "[]" jra
Unix username:        jht
NT username:          jht
Account Flags:        [U          ]
User SID:             S-1-5-21-729263-4123605-1186429-3000
Primary Group SID:    S-1-5-21-729263-4123605-1186429-513
Full Name:            John H Terpstra,Utah Office
Home Directory:       \\aurora\jht
HomeDir Drive:        H:
Logon Script:         scripts\logon.bat
Profile Path:         \\aurora\profiles\jht
Domain:               MIDEARTH
Account desc:         BluntObject
Workstations:
Logon time:           0
Logoff time:          Mon, 18 Jan 2038 20:14:07 GMT
Kickoff time:         0
Password last set:    Sun, 03 Jul 2005 23:19:18 GMT
Password can change:  Sun, 03 Jul 2005 23:19:18 GMT
Password must change: Mon, 18 Jan 2038 20:14:07 GMT
Last bad password   : 0
Bad password count  : 0
Logon hours         : FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
</screen>
		</para>

		</sect5>

		</sect4>

		<sect4>
		<title>Domain Account Policy Managment</title>

		<para>
<indexterm><primary>domain account access policies</primary></indexterm>
<indexterm><primary>access policies</primary></indexterm>
		To view the domain account access policies that may be configured execute:
<screen>
&rootprompt; pdbedit -P ?
No account policy by that name
Account policy names are :
min password length
password history
user must logon to change password
maximum password age
minimum password age
lockout duration
reset count minutes
bad lockout attempt
disconnect time
refuse machine password change
</screen>
		</para>

		<para>
		Commands will be executed to establish controls for our domain as follows:
		</para>

		<orderedlist>
			<listitem><para>min password length = 8 characters.</para></listitem>
			<listitem><para>password history = last 4 passwords.</para></listitem>
			<listitem><para>maximum password age = 90 days.</para></listitem>
			<listitem><para>minimum password age = 7 days.</para></listitem>
			<listitem><para>bad lockout attempt = 8 bad logon attempts.</para></listitem>
			<listitem><para>lockout duration = forever, account must be manually reenabled.</para></listitem>
		</orderedlist>

		<para>
		The following command execution will achieve these settings:
<screen>
&rootprompt; pdbedit -P "min password length" -C 8
account policy value for min password length was 5
account policy value for min password length is now 8
&rootprompt; pdbedit -P "password history" -C 4
account policy value for password history was 0
account policy value for password history is now 4
&rootprompt; pdbedit -P "maximum password age" -C 7776000
account policy value for maximum password age was 4294967295
account policy value for maximum password age is now 7776000
&rootprompt; pdbedit -P "minimum password age" -C 7
account policy value for minimum password age was 0
account policy value for minimum password age is now 7
&rootprompt; pdbedit -P "bad lockout attempt" -C 8
account policy value for bad lockout attempt was 0
account policy value for bad lockout attempt is now 8
&rootprompt; pdbedit -P "lockout duration" -C -1
account policy value for lockout duration was 30
account policy value for lockout duration is now 4294967295
</screen>
		</para>

<note><para>
To set the maximum (infinite) lockout time use the value of -1.
</para></note>

<warning><para>
Account policies must be set individually on each PDC and BDC. At this time (Samba 3.0.11 to Samba 3.0.14a)
account policies are not replicated automatically. This may be fixed before Samba 3.0.20 ships or some
time there after.
</para></warning>

		</sect4>

		</sect3>

		<sect3>
		<title>Account Migration</title>

		<para>
		<indexterm><primary>pdbedit</primary></indexterm>
<indexterm><primary>migrate accounts</primary></indexterm>
<indexterm><primary>authentication</primary></indexterm>
		The <command>pdbedit</command> tool allows migration of authentication (account)
		databases from one backend to another. For example, to migrate accounts from an
		old <filename>smbpasswd</filename> database to a <parameter>tdbsam</parameter>
		backend:
		</para>

		<procedure>
			<step><para>
			Set the <smbconfoption name="passdb backend">tdbsam, smbpasswd</smbconfoption>.
			</para></step>

			<step><para>
<indexterm><primary>pdbedit</primary></indexterm>
			Execute:
<screen>
&rootprompt;<userinput>pdbedit -i smbpasswd -e tdbsam</userinput>
</screen>
			</para></step>

			<step><para>
<indexterm><primary>smbpasswd</primary></indexterm>
			Remove the <parameter>smbpasswd</parameter> from the passdb backend
			configuration in &smb.conf;.
			</para></step>
		</procedure>

	</sect3>
	</sect2>
</sect1>

<sect1>
<title>Password Backends</title>

<para>
<indexterm><primary>account database</primary></indexterm>
<indexterm><primary>SMB/CIFS server</primary></indexterm>
Samba offers the greatest flexibility in backend account database design of any SMB/CIFS server
technology available today. The flexibility is immediately obvious as one begins to explore this
capability.
</para>

<para>
<indexterm><primary>multiple backends</primary></indexterm>
<indexterm><primary>tdbsam databases</primary></indexterm>
It is possible to specify not only multiple password backends, but even multiple
backends of the same type. For example, to use two different <literal>tdbsam</literal> databases:

<smbconfblock>
<smbconfoption name="passdb backend">tdbsam:/etc/samba/passdb.tdb tdbsam:/etc/samba/old-passdb.tdb</smbconfoption>
</smbconfblock>

What is possible is not always sensible. Be careful to avoid complexity to the point that it
may be said that the solution is <quote>too clever by half!</quote>
</para>


	<sect2>
	<title>Plaintext</title>

		<para>
<indexterm><primary>user database</primary></indexterm>
<indexterm><primary>/etc/samba/smbpasswd</primary></indexterm>
<indexterm><primary>/etc/smbpasswd</primary></indexterm>
<indexterm><primary>password encryption</primary></indexterm>
<indexterm><primary>/etc/passwd</primary></indexterm>
<indexterm><primary>PAM</primary></indexterm>
		Older versions of Samba retrieved user information from the UNIX user database 
		and eventually some other fields from the file <filename>/etc/samba/smbpasswd</filename>
		or <filename>/etc/smbpasswd</filename>. When password encryption is disabled, no 
		SMB-specific data is stored at all. Instead, all operations are conducted via the way
		that the Samba host OS will access its <filename>/etc/passwd</filename> database.
		On most Linux systems, for example, all user and group resolution is done via PAM.
		</para>

	</sect2>

	<sect2>
	<title>smbpasswd: Encrypted Password Database</title>

		<para>
		<indexterm><primary>SAM backend</primary><secondary>smbpasswd</secondary></indexterm>
<indexterm><primary>user account</primary></indexterm>
<indexterm><primary>LM/NT password hashes</primary></indexterm>
<indexterm><primary>smbpasswd</primary></indexterm>
		Traditionally, when configuring <smbconfoption name="encrypt passwords">yes</smbconfoption>
		in Samba's &smb.conf; file, user account information such as username, LM/NT password hashes,
		password change times, and account flags have been stored in the <filename>smbpasswd(5)</filename>
		file. There are several disadvantages to this approach for sites with large numbers of users
		(counted in the thousands).
		</para>

		<itemizedlist>
		<listitem><para>
<indexterm><primary>lookups</primary></indexterm>
		The first problem is that all lookups must be performed sequentially. Given that
		there are approximately two lookups per domain logon (one during intial logon validation
		and one for a session connection setup, such as when mapping a network drive or printer), this
		is a performance bottleneck for large sites. What is needed is an indexed approach
		such as that used in databases.
		</para></listitem>

		<listitem><para>
<indexterm><primary>smbpasswd</primary></indexterm>
<indexterm><primary>replicate</primary></indexterm>
<indexterm><primary>rsync</primary></indexterm>
<indexterm><primary>ssh</primary></indexterm>
<indexterm><primary>custom scripts</primary></indexterm>
		The second problem is that administrators who desire to replicate an smbpasswd file
		to more than one Samba server are left to use external tools such as
		<command>rsync(1)</command> and <command>ssh(1)</command> and write custom,
		in-house scripts.
		</para></listitem>

		<listitem><para>
<indexterm><primary>smbpasswd</primary></indexterm>
<indexterm><primary>home directory</primary></indexterm>
<indexterm><primary>password expiration</primary></indexterm>
<indexterm><primary>relative identifier</primary></indexterm>
<indexterm><primary>relative identifier</primary><see>RID</see></indexterm>
		Finally, the amount of information that is stored in an smbpasswd entry leaves
		no room for additional attributes such as a home directory, password expiration time,
		or even a relative identifier (RID).
		</para></listitem>
		</itemizedlist>

		<para>
<indexterm><primary>user attributes</primary></indexterm>
<indexterm><primary>smbd</primary></indexterm>
<indexterm><primary>API</primary></indexterm>
<indexterm><primary>samdb interface</primary></indexterm>
		As a result of these deficiencies, a more robust means of storing user attributes
		used by smbd was developed. The API that defines access to user accounts
		is commonly referred to as the samdb interface (previously, this was called the passdb
		API and is still so named in the Samba source code trees). 
		</para>

		<para>
<indexterm><primary>passdb backends</primary></indexterm>
<indexterm><primary>smbpasswd plaintext database</primary></indexterm>
<indexterm><primary>tdbsam</primary></indexterm>
<indexterm><primary>ldapsam</primary></indexterm>
<indexterm><primary>enterprise</primary></indexterm>
		Samba provides an enhanced set of passdb backends that overcome the deficiencies
		of the smbpasswd plaintext database. These are tdbsam and ldapsam.
		Of these, ldapsam will be of most interest to large corporate or enterprise sites.
		</para>

	</sect2>

	<sect2>
	<title>tdbsam</title>

		<para>
		<indexterm><primary>SAM backend</primary><secondary>tdbsam</secondary></indexterm>
<indexterm><primary>trivial database</primary><see>TDB</see></indexterm>
<indexterm><primary>machine account</primary></indexterm>
		Samba can store user and machine account data in a <quote>TDB</quote> (trivial database).
		Using this backend does not require any additional configuration. This backend is
		recommended for new installations that do not require LDAP.
		</para>

		<para>
<indexterm><primary>tdbsam</primary></indexterm>
<indexterm><primary>PDC</primary></indexterm>
<indexterm><primary>BDC</primary></indexterm>
<indexterm><primary>scalability</primary></indexterm>
		As a general guide, the Samba Team does not recommend using the tdbsam backend for sites
		that have 250 or more users. Additionally, tdbsam is not capable of scaling for use
		in sites that require PDB/BDC implementations that require replication of the account
		database. Clearly, for reason of scalability, the use of ldapsam should be encouraged.
		</para>

		<para>
<indexterm><primary>250-user limit</primary></indexterm>
<indexterm><primary>performance-based</primary></indexterm>
<indexterm><primary>tdbsam</primary></indexterm>
		The recommendation of a 250-user limit is purely based on the notion that this
		would generally involve a site that has routed networks, possibly spread across
		more than one physical location. The Samba Team has not at this time established
		the performance-based scalability limits of the tdbsam architecture.
		</para>

		<para>
<indexterm><primary>4,500 user accounts</primary></indexterm>
<indexterm><primary>passdb backend</primary></indexterm>
<indexterm><primary>tdbsam</primary></indexterm>
<indexterm><primary>SambaSAMAccount</primary></indexterm>
		There are sites that have thousands of users and yet require only one server.
		One site recently reported having 4,500 user accounts on one UNIX system and
		reported excellent performance with the <literal>tdbsam</literal> passdb backend.
		The limitation of where the <literal>tdbsam</literal> passdb backend can be used
		is not one pertaining to a limitation in the TDB storage system, it is based
		only on the need for a reliable distribution mechanism for the SambaSAMAccount
		backend.
		</para>

	</sect2>

	<sect2>
	<title>ldapsam</title>

		<para>
<indexterm><primary>LDAP</primary></indexterm>
<indexterm><primary>ldapsam</primary></indexterm>
		<indexterm><primary>SAM backend</primary><secondary>ldapsam</secondary></indexterm>
		There are a few points to stress that the ldapsam does not provide. The LDAP
		support referred to in this documentation does not include:
		</para>

		<itemizedlist>
			<listitem><para>A means of retrieving user account information from
			a Windows 200x Active Directory server.</para></listitem>
			<listitem><para>A means of replacing /etc/passwd.</para></listitem>
		</itemizedlist>

		<para>
<indexterm><primary>LDAP</primary></indexterm>
<indexterm><primary>NSS</primary></indexterm>
<indexterm><primary>PAM</primary></indexterm>
<indexterm><primary>LGPL</primary></indexterm>
		The second item can be accomplished by using LDAP NSS and PAM modules. LGPL versions of these libraries can be
		obtained from <ulink url="http://www.padl.com/">PADL Software</ulink>.  More information about the
		configuration of these packages may be found in <ulink url="http://safari.oreilly.com/?XmlId=1-56592-491-6">
		<emphasis>LDAP, System Administration</emphasis> by Gerald Carter, Chapter 6, Replacing NIS"</ulink>.
		</para>

		<para>
<indexterm><primary>LDAP directory</primary></indexterm>
<indexterm><primary>smbpasswd</primary></indexterm>
<indexterm><primary>directory server</primary></indexterm>
		This document describes how to use an LDAP directory for storing Samba user
		account information traditionally stored in the smbpasswd(5) file. It is
		assumed that the reader already has a basic understanding of LDAP concepts
		and has a working directory server already installed. For more information
		on LDAP architectures and directories, please refer to the following sites:
		</para>

		<itemizedlist>
			<listitem><para><ulink url="http://www.openldap.org/">OpenLDAP</ulink></para></listitem>
			<listitem><para><ulink url="http://www.sun.com/software/products/directory_srvr_ee/index.xml">
				Sun One Directory Server</ulink></para></listitem>
			<listitem><para><ulink url="http://www.novell.com/products/edirectory/">Novell eDirectory</ulink></para></listitem>
			<listitem><para><ulink url="http://www-306.ibm.com/software/tivoli/products/directory-server/">IBM
				Tivoli Directory Server</ulink></para></listitem>
			<listitem><para><ulink url="http://www.redhat.com/software/rha/directory/">Red Hat Directory
				Server</ulink></para></listitem>
			<listitem><para><ulink url="http://www.linuxsecurity.com/content/view/119229">Fedora Directory
				Server</ulink></para></listitem>
		</itemizedlist>

		<para>
		Two additional Samba resources that may prove to be helpful are:
		</para>

		<itemizedlist>
			<listitem><para>
<indexterm><primary>Samba-PDC-LDAP-HOWTO</primary></indexterm>
			The <ulink url="http://www.unav.es/cti/ldap-smb/ldap-smb-3-howto.html">Samba-PDC-LDAP-HOWTO</ulink>
			maintained by Ignacio Coupeau.
			</para></listitem>

			<listitem><para>
<indexterm><primary>IDEALX</primary></indexterm>
<indexterm><primary>NT migration scripts</primary></indexterm>
<indexterm><primary>smbldap-tools</primary></indexterm>
			The NT migration scripts from <ulink url="http://samba.idealx.org/">IDEALX</ulink> that are
			geared to manage users and groups in such a Samba-LDAP domain controller configuration.
			Idealx also produced the smbldap-tools and the Interactive Console Management tool.
			</para></listitem>
		</itemizedlist>

		<sect3>
		<title>Supported LDAP Servers</title>

			<para>
<indexterm><primary>LDAP</primary></indexterm>
<indexterm><primary>ldapsam</primary></indexterm>
<indexterm><primary>OpenLDAP</primary></indexterm>
<indexterm><primary>Netscape's Directory Server</primary></indexterm>
			The LDAP ldapsam code was developed and tested using the OpenLDAP 2.x server and
			client libraries. The same code should work with Netscape's Directory Server and client SDK.
			However, there are bound to be compile errors and bugs. These should not be hard to fix.
			Please submit fixes via the process outlined in <link linkend="bugreport">Reporting Bugs</link>.
			</para>

			<para>
			Samba is capable of working with any standards-compliant LDAP server.
			</para>

		</sect3>

		<sect3>
		<title>Schema and Relationship to the RFC 2307 posixAccount</title>


			<para>
			Samba-3.0 includes the necessary schema file for OpenLDAP 2.x in the
			<filename>examples/LDAP/samba.schema</filename> directory of the source code distribution
			tarball. The schema entry for the sambaSamAccount ObjectClass is shown here:
<programlisting>
ObjectClass (1.3.6.1.4.1.7165.2.2.6 NAME 'sambaSamAccount' SUP top AUXILIARY
    DESC 'Samba-3.0 Auxiliary SAM Account'
    MUST ( uid $ sambaSID )
    MAY  ( cn $ sambaLMPassword $ sambaNTPassword $ sambaPwdLastSet $
          sambaLogonTime $ sambaLogoffTime $ sambaKickoffTime $
          sambaPwdCanChange $ sambaPwdMustChange $ sambaAcctFlags $
          displayName $ sambaHomePath $ sambaHomeDrive $ sambaLogonScript $
          sambaProfilePath $ description $ sambaUserWorkstations $
          sambaPrimaryGroupSID $ sambaDomainName ))
</programlisting>
			</para>

			<para>
<indexterm><primary>samba.schema</primary></indexterm>
<indexterm><primary>OpenLDAP</primary></indexterm>
<indexterm><primary>OID</primary></indexterm>
			The <filename>samba.schema</filename> file has been formatted for OpenLDAP 2.0/2.1.
			The Samba Team owns the OID space used by the above schema and recommends its use.
			If you translate the schema to be used with Netscape DS, please submit the modified
			schema file as a patch to <ulink url="mailto:jerry@samba.org">jerry@samba.org</ulink>.
			</para>

			<para>
<indexterm><primary>smbpasswd</primary></indexterm>
<indexterm><primary>/etc/passwd</primary></indexterm>
<indexterm><primary>sambaSamAccount</primary></indexterm>
<indexterm><primary>AUXILIARY</primary></indexterm>
<indexterm><primary>ObjectClass</primary></indexterm>
<indexterm><primary>LDAP</primary></indexterm>
<indexterm><primary>RFC 2307.</primary></indexterm>
			Just as the smbpasswd file is meant to store information that provides information
			additional to  a user's <filename>/etc/passwd</filename> entry, so is the sambaSamAccount
			object meant to supplement the UNIX user account information. A sambaSamAccount is an
			<constant>AUXILIARY</constant> ObjectClass, so it can be used to augment existing
			user account information in the LDAP directory, thus providing information needed
			for Samba account handling. However, there are several fields (e.g., uid) that overlap
			with the posixAccount ObjectClass outlined in RFC 2307. This is by design.
			</para>

			<para>
<indexterm><primary>account information</primary></indexterm>
<indexterm><primary>sambaSamAccount</primary></indexterm>
<indexterm><primary>posixAccount</primary></indexterm>
<indexterm><primary>ObjectClasses</primary></indexterm>
<indexterm><primary>smbd</primary></indexterm>
<indexterm><primary>getpwnam</primary></indexterm>
<indexterm><primary>LDAP</primary></indexterm>
<indexterm><primary>NIS</primary></indexterm>
<indexterm><primary>NSS</primary></indexterm>
			In order to store all user account information (UNIX and Samba) in the directory,
			it is necessary to use the sambaSamAccount and posixAccount ObjectClasses in
			combination. However, <command>smbd</command> will still obtain the user's UNIX account
			information via the standard C library calls, such as getpwnam().
			This means that the Samba server must also have the LDAP NSS library installed
			and functioning correctly. This division of information makes it possible to
			store all Samba account information in LDAP, but still maintain UNIX account
			information in NIS while the network is transitioning to a full LDAP infrastructure.
			</para>
		</sect3>

		<sect3>
		<title>OpenLDAP Configuration</title>

		<para>
<indexterm><primary>sambaSamAccount</primary></indexterm>
<indexterm><primary>OpenLDAP</primary></indexterm>
<indexterm><primary>slapd</primary></indexterm>
<indexterm><primary>samba.schema</primary></indexterm>
		To include support for the sambaSamAccount object in an OpenLDAP directory
		server, first copy the samba.schema file to slapd's configuration directory.
		The samba.schema file can be found in the directory <filename>examples/LDAP</filename>
		in the Samba source distribution.
<screen>
&rootprompt;<userinput>cp samba.schema /etc/openldap/schema/</userinput>
</screen>
		</para>

		<para>
<indexterm><primary>samba.schema</primary></indexterm>
<indexterm><primary>slapd.conf</primary></indexterm>
<indexterm><primary>sambaSamAccount</primary></indexterm>
<indexterm><primary>cosine.schema</primary></indexterm>
<indexterm><primary>uid</primary></indexterm>
<indexterm><primary>inetorgperson.schema</primary></indexterm>
<indexterm><primary>displayName</primary></indexterm>
<indexterm><primary>attribute</primary></indexterm>
		Next, include the <filename>samba.schema</filename> file in <filename>slapd.conf</filename>.
		The sambaSamAccount object contains two attributes that depend on other schema
		files. The <parameter>uid</parameter> attribute is defined in <filename>cosine.schema</filename> and
		the <parameter>displayName</parameter> attribute is defined in the <filename>inetorgperson.schema</filename>
		file. Both of these must be included before the <filename>samba.schema</filename> file.
<programlisting>
## /etc/openldap/slapd.conf

## schema files (core.schema is required by default)
include	           /etc/openldap/schema/core.schema

## needed for sambaSamAccount
include            /etc/openldap/schema/cosine.schema
include            /etc/openldap/schema/inetorgperson.schema
include            /etc/openldap/schema/nis.schema
include            /etc/openldap/schema/samba.schema
....
</programlisting>
		</para>

		<para>
<indexterm><primary>sambaSamAccount</primary></indexterm>
<indexterm><primary>posixAccount</primary></indexterm>
<indexterm><primary>posixGroup</primary></indexterm>
<indexterm><primary>ObjectClasses</primary></indexterm>
		It is recommended that you maintain some indices on some of the most useful attributes,
		as in the following example, to speed up searches made on sambaSamAccount ObjectClasses
		(and possibly posixAccount and posixGroup as well):
		</para>

<para>
<programlisting>
# Indices to maintain
## required by OpenLDAP
index objectclass             eq

index cn                      pres,sub,eq
index sn                      pres,sub,eq
## required to support pdb_getsampwnam
index uid                     pres,sub,eq
## required to support pdb_getsambapwrid()
index displayName             pres,sub,eq

## uncomment these if you are storing posixAccount and
## posixGroup entries in the directory as well
##index uidNumber               eq
##index gidNumber               eq
##index memberUid               eq

index   sambaSID              eq
index   sambaPrimaryGroupSID  eq
index   sambaDomainName       eq
index   default               sub
</programlisting>
</para>

		<para>
		Create the new index by executing:
<screen>
&rootprompt;./sbin/slapindex -f slapd.conf
</screen>
		</para>

		<para>
		Remember to restart slapd after making these changes:
<screen>
&rootprompt;<userinput>/etc/init.d/slapd restart</userinput>
</screen>
		</para>

		</sect3>

		<sect3>
		<title>Initialize the LDAP Database</title>

		<para>
<indexterm><primary>LDAP database</primary></indexterm>
<indexterm><primary>account containers</primary></indexterm>
<indexterm><primary>LDIF file</primary></indexterm>
<indexterm><primary>DNS</primary></indexterm>
		Before you can add accounts to the LDAP database, you must create the account containers
		that they will be stored in. The following LDIF file should be modified to match your
		needs (DNS entries, and so on):
<programlisting>
# Organization for Samba Base
dn: dc=quenya,dc=org
objectclass: dcObject
objectclass: organization
dc: quenya
o: Quenya Org Network
description: The Samba-3 Network LDAP Example

# Organizational Role for Directory Management
dn: cn=Manager,dc=quenya,dc=org
objectclass: organizationalRole
cn: Manager
description: Directory Manager

# Setting up container for Users OU
dn: ou=People,dc=quenya,dc=org
objectclass: top
objectclass: organizationalUnit
ou: People

# Setting up admin handle for People OU
dn: cn=admin,ou=People,dc=quenya,dc=org
cn: admin
objectclass: top
objectclass: organizationalRole
objectclass: simpleSecurityObject
userPassword: {SSHA}c3ZM9tBaBo9autm1dL3waDS21+JSfQVz

# Setting up container for groups
dn: ou=Groups,dc=quenya,dc=org
objectclass: top
objectclass: organizationalUnit
ou: Groups

# Setting up admin handle for Groups OU
dn: cn=admin,ou=Groups,dc=quenya,dc=org
cn: admin
objectclass: top
objectclass: organizationalRole
objectclass: simpleSecurityObject
userPassword: {SSHA}c3ZM9tBaBo9autm1dL3waDS21+JSfQVz

# Setting up container for computers
dn: ou=Computers,dc=quenya,dc=org
objectclass: top
objectclass: organizationalUnit
ou: Computers

# Setting up admin handle for Computers OU
dn: cn=admin,ou=Computers,dc=quenya,dc=org
cn: admin
objectclass: top
objectclass: organizationalRole
objectclass: simpleSecurityObject
userPassword: {SSHA}c3ZM9tBaBo9autm1dL3waDS21+JSfQVz
</programlisting>
		</para>

		<para>
<indexterm><primary>userPassword</primary></indexterm>
<indexterm><primary>slappasswd</primary></indexterm>
		The userPassword shown above should be generated using <command>slappasswd</command>.
		</para>

		<para>
<indexterm><primary>LDIF</primary></indexterm>
<indexterm><primary>LDAP</primary></indexterm>
		The following command will then load the contents of the LDIF file into the LDAP
		database.
<indexterm><primary>slapadd</primary></indexterm>
<screen>
&prompt;<userinput>slapadd -v -l initldap.dif</userinput>
</screen>
		</para>

		<para>
		Do not forget to secure your LDAP server with an adequate access control list
		as well as an admin password.
		</para>

		<note><para>
<indexterm><primary>secrets.tdb</primary></indexterm>
		Before Samba can access the LDAP server, you need to store the LDAP admin password
		in the Samba-3 <filename>secrets.tdb</filename> database by:
<indexterm><primary>smbpasswd</primary></indexterm>
<screen>
&rootprompt;<userinput>smbpasswd -w <replaceable>secret</replaceable></userinput>
</screen>
		</para></note>

		</sect3>

		<sect3>
		<title>Configuring Samba</title>

			<para>
<indexterm><primary>LDAP</primary></indexterm>
<indexterm><primary>smbd</primary></indexterm>
			The following parameters are available in &smb.conf; only if your version of Samba was built with
			LDAP support. Samba automatically builds with LDAP support if the LDAP libraries are found. The 
			best method to verify that Samba was built with LDAP support is:
<screen>
&rootprompt; smbd -b | grep LDAP
   HAVE_LDAP_H
   HAVE_LDAP
   HAVE_LDAP_DOMAIN2HOSTLIST
   HAVE_LDAP_INIT
   HAVE_LDAP_INITIALIZE
   HAVE_LDAP_SET_REBIND_PROC
   HAVE_LIBLDAP
   LDAP_SET_REBIND_PROC_ARGS
</screen>
			If the build of the <command>smbd</command> command you are using does not produce output
			that includes <literal>HAVE_LDAP_H</literal> it is necessary to discover why the LDAP headers
			and libraries were not found during compilation.
			</para>

			<para>LDAP-related smb.conf options include these:
			<smbconfblock>
			<smbconfoption name="passdb backend">ldapsam:url</smbconfoption>
			<smbconfoption name="ldap admin dn"/>
			<smbconfoption name="ldap delete dn"/>
			<smbconfoption name="ldap filter"/>
			<smbconfoption name="ldap group suffix"/>
			<smbconfoption name="ldap idmap suffix"/>
			<smbconfoption name="ldap machine suffix"/>
			<smbconfoption name="ldap passwd sync"/>
			<smbconfoption name="ldap ssl"/>
			<smbconfoption name="ldap suffix"/>
			<smbconfoption name="ldap user suffix"/>
			<smbconfoption name="ldap replication sleep"/>
			<smbconfoption name="ldap timeout"/>
			<smbconfoption name="ldap page size"/>
			</smbconfblock>
			</para>

			<para>
			These are described in the &smb.conf; man page and so are not repeated here. However, an example 
			for use with an LDAP directory is shown in <link linkend="confldapex">the Configuration with LDAP.</link>
			</para>

<example id="confldapex">
<title>Configuration with LDAP</title>
<smbconfblock>
<smbconfsection name="[global]"/>
<smbconfoption name="security">user</smbconfoption>
<smbconfoption name="encrypt passwords">yes</smbconfoption>
<smbconfoption name="netbios name">MORIA</smbconfoption>
<smbconfoption name="workgroup">NOLDOR</smbconfoption>

<smbconfcomment>LDAP related parameters:</smbconfcomment>

<smbconfcomment>Define the DN used when binding to the LDAP servers.</smbconfcomment>
<smbconfcomment>The password for this DN is not stored in smb.conf</smbconfcomment>
<smbconfcomment>Set it using 'smbpasswd -w secret' to store the</smbconfcomment>
<smbconfcomment>passphrase in the secrets.tdb file.</smbconfcomment>
<smbconfcomment>If the "ldap admin dn" value changes, it must be reset.</smbconfcomment>
<smbconfoption name="ldap admin dn">"cn=Manager,dc=quenya,dc=org"</smbconfoption>

<smbconfcomment>SSL directory connections can be configured by:</smbconfcomment>
<smbconfcomment>('off', 'start tls', or 'on' (default))</smbconfcomment>
<smbconfoption name="ldap ssl">start tls</smbconfoption>

<smbconfcomment>syntax: passdb backend = ldapsam:ldap://server-name[:port]</smbconfcomment>
<smbconfoption name="passdb backend">ldapsam:ldap://frodo.quenya.org</smbconfoption>

<smbconfcomment>smbpasswd -x delete the entire dn-entry</smbconfcomment>
<smbconfoption name="ldap delete dn">no</smbconfoption>

<smbconfcomment>The machine and user suffix are added to the base suffix</smbconfcomment>
<smbconfcomment>wrote WITHOUT quotes. NULL suffixes by default</smbconfcomment>
<smbconfoption name="ldap user suffix">ou=People</smbconfoption>
<smbconfoption name="ldap group suffix">ou=Groups</smbconfoption>
<smbconfoption name="ldap machine suffix">ou=Computers</smbconfoption>

<smbconfcomment>Trust UNIX account information in LDAP</smbconfcomment>
<smbconfcomment> (see the smb.conf man page for details)</smbconfcomment>

<smbconfcomment>Specify the base DN to use when searching the directory</smbconfcomment>
<smbconfoption name="ldap suffix">dc=quenya,dc=org</smbconfoption>
</smbconfblock>
</example>

		</sect3>

		<sect3>
		<title>Accounts and Groups Management</title>

			<para>
			<indexterm><primary>User Management</primary></indexterm>
			<indexterm><primary>User Accounts</primary><secondary>Adding/Deleting</secondary></indexterm>
			Because user accounts are managed through the sambaSamAccount ObjectClass, you should
			modify your existing administration tools to deal with sambaSamAccount attributes.
			</para>

			<para>
<indexterm><primary>sambaSamAccount</primary></indexterm>
<indexterm><primary>/etc/openldap/sldap.conf</primary></indexterm>
<indexterm><primary>NSS</primary></indexterm>
			Machine accounts are managed with the sambaSamAccount ObjectClass, just
			like user accounts. However, it is up to you to store those accounts
			in a different tree of your LDAP namespace. You should use
			<quote>ou=Groups,dc=quenya,dc=org</quote> to store groups and
			<quote>ou=People,dc=quenya,dc=org</quote> to store users. Just configure your
			NSS and PAM accordingly (usually, in the <filename>/etc/openldap/sldap.conf</filename>
			configuration file).
			</para>

			<para>
<indexterm><primary>POSIX</primary></indexterm>
<indexterm><primary>posixGroup</primary></indexterm>
<indexterm><primary>Domain Groups</primary></indexterm>
<indexterm><primary>ADS</primary></indexterm>
			In Samba-3, the group management system is based on POSIX
			groups. This means that Samba makes use of the posixGroup ObjectClass.
			For now, there is no NT-like group system management (global and local
			groups). Samba-3 knows only about <constant>Domain Groups</constant>
			and, unlike MS Windows 2000 and Active Directory, Samba-3 does not
			support nested groups. 
			</para>

		</sect3>

		<sect3>
		<title>Security and sambaSamAccount</title>


			<para>
<indexterm><primary>sambaSAMAccount</primary></indexterm>
			There are two important points to remember when discussing the security
			of sambaSAMAccount entries in the directory.
			</para>

			<itemizedlist>
				<listitem><para><emphasis>Never</emphasis> retrieve the SambaLMPassword or
<indexterm><primary>SambaNTPassword</primary></indexterm>
				SambaNTPassword attribute values over an unencrypted LDAP session.</para></listitem>
				<listitem><para><emphasis>Never</emphasis> allow non-admin users to
				view the SambaLMPassword or SambaNTPassword attribute values.</para></listitem>
			</itemizedlist>

			<para>
<indexterm><primary>clear-text</primary></indexterm>
<indexterm><primary>impersonate</primary></indexterm>
<indexterm><primary>LM/NT password hashes</primary></indexterm>
			These password hashes are clear-text equivalents and can be used to impersonate
			the user without deriving the original clear-text strings. For more information
			on the details of LM/NT password hashes, refer to <link linkend="passdb">the
			Account Information Database section</link>.
			</para>

			<para>
<indexterm><primary>encrypted session</primary></indexterm>
<indexterm><primary>StartTLS</primary></indexterm>
<indexterm><primary>LDAPS</primary></indexterm>
<indexterm><primary>secure communications</primary></indexterm>
			To remedy the first security issue, the <smbconfoption name="ldap ssl"/> &smb.conf;
			parameter defaults to require an encrypted session (<smbconfoption name="ldap
			ssl">on</smbconfoption>) using the default port of <constant>636</constant> when
			contacting the directory server. When using an OpenLDAP server, it
			is possible to use the StartTLS LDAP extended operation in the place of LDAPS.
			In either case, you are strongly encouraged to use secure communications protocols
			(so do not set <smbconfoption name="ldap ssl">off</smbconfoption>).
			</para>

			<para>
<indexterm><primary>LDAPS</primary></indexterm>
<indexterm><primary>StartTLS</primary></indexterm>
<indexterm><primary>LDAPv3</primary></indexterm>
			Note that the LDAPS protocol is deprecated in favor of the LDAPv3 StartTLS
			extended operation. However, the OpenLDAP library still provides support for
			the older method of securing communication between clients and servers.
			</para>

			<para>
<indexterm><primary>harvesting password hashes</primary></indexterm>
<indexterm><primary>ACL</primary></indexterm>
<indexterm><primary>slapd.conf</primary></indexterm>
			The second security precaution is to prevent non-administrative users from
			harvesting password hashes from the directory. This can be done using the
			following ACL in <filename>slapd.conf</filename>:
			</para>

<para>
<programlisting>
## allow the "ldap admin dn" access, but deny everyone else
access to attrs=SambaLMPassword,SambaNTPassword
     by dn="cn=Samba Admin,ou=People,dc=quenya,dc=org" write
     by * none
</programlisting>
</para>

		</sect3>

		<sect3>
		<title>LDAP Special Attributes for sambaSamAccounts</title>

			<para> The sambaSamAccount ObjectClass is composed of the attributes shown in next tables: <link
			linkend="attribobjclPartA">Part A</link>, and <link linkend="attribobjclPartB">Part B</link>. 
			</para>

			<table frame="all" id="attribobjclPartA">
				<title>Attributes in the sambaSamAccount ObjectClass (LDAP), Part A</title>
			<tgroup cols="2" align="justify">
					<colspec align="left"/>
					<colspec align="justify" colwidth="1*"/>
			<tbody>
				<row><entry><constant>sambaLMPassword</constant></entry><entry>The LanMan password 16-byte hash stored as a character
						representation of a hexadecimal string.</entry></row>
				<row><entry><constant>sambaNTPassword</constant></entry><entry>The NT password 16-byte hash stored as a character
						representation of a hexadecimal string.</entry></row>
				<row><entry><constant>sambaPwdLastSet</constant></entry><entry>The integer time in seconds since 1970 when the
						<constant>sambaLMPassword</constant> and <constant>sambaNTPassword</constant> attributes were last set.
				</entry></row>

				<row><entry><constant>sambaAcctFlags</constant></entry><entry>String of 11 characters surrounded by square brackets [ ]
						representing account flags such as U (user), W (workstation), X (no password expiration),
						I (domain trust account), H (home dir required), S (server trust account),
						and D (disabled).</entry></row>

				<row><entry><constant>sambaLogonTime</constant></entry><entry>Integer value currently unused.</entry></row>

				<row><entry><constant>sambaLogoffTime</constant></entry><entry>Integer value currently unused.</entry></row>

				<row><entry><constant>sambaKickoffTime</constant></entry><entry>Specifies the time (UNIX time format) when the user
				will be locked down and cannot login any longer. If this attribute is omitted, then the account will never expire.
				Using this attribute together with shadowExpire of the shadowAccount ObjectClass will enable accounts to	
				expire completely on an exact date.</entry></row>

				<row><entry><constant>sambaPwdCanChange</constant></entry><entry>Specifies the time (UNIX time format)
				after which the user is allowed to change his password. If this attribute is not set, the user will be free
				to change his password whenever he wants.</entry></row> 

				<row><entry><constant>sambaPwdMustChange</constant></entry><entry>Specifies the time (UNIX time format) when the user is
				forced to change his password. If this value is set to 0, the user will have to change his password at first login.
				If this attribute is not set, then the password will never expire.</entry></row>

				<row><entry><constant>sambaHomeDrive</constant></entry><entry>Specifies the drive letter to which to map the
				UNC path specified by sambaHomePath. The drive letter must be specified in the form <quote>X:</quote>
				where X is the letter of the drive to map. Refer to the <quote>logon drive</quote> parameter in the
				smb.conf(5) man page for more information.</entry></row>

				<row><entry><constant>sambaLogonScript</constant></entry><entry>The sambaLogonScript property specifies the path of
				the user's logon script, .CMD, .EXE, or .BAT file. The string can be null. The path
				is relative to the netlogon share. Refer to the <smbconfoption name="logon script"/> parameter in the
				&smb.conf; man page for more information.</entry></row>

				<row><entry><constant>sambaProfilePath</constant></entry><entry>Specifies a path to the user's profile.
				This value can be a null string, a local absolute path, or a UNC path. Refer to the
				<smbconfoption name="logon path"/> parameter in the &smb.conf; man page for more information.</entry></row>

				<row><entry><constant>sambaHomePath</constant></entry><entry>The sambaHomePath property specifies the path of
				the home directory for the user. The string can be null. If sambaHomeDrive is set and specifies
				a drive letter, sambaHomePath should be a UNC path. The path must be a network
				UNC path of the form <filename>\\server\share\directory</filename>. This value can be a null string.
				Refer to the <command>logon home</command> parameter in the &smb.conf; man page for more information.
				</entry></row>
			</tbody>
			</tgroup></table>


			<table frame="all" id="attribobjclPartB">
				<title>Attributes in the sambaSamAccount ObjectClass (LDAP), Part B</title>
			<tgroup cols="2" align="justify">
					<colspec align="left"/>
					<colspec align="justify" colwidth="1*"/>
			<tbody>
				<row><entry><constant>sambaUserWorkstations</constant></entry><entry>Here you can give a comma-separated list of machines
				on which the user is allowed to login. You may observe problems when you try to connect to a Samba domain member.
				Because domain members are not in this list, the domain controllers will reject them. Where this attribute is omitted,
				the default implies no restrictions.
				</entry></row>

				<row><entry><constant>sambaSID</constant></entry><entry>The security identifier(SID) of the user.
				The Windows equivalent of UNIX UIDs.</entry></row>

				<row><entry><constant>sambaPrimaryGroupSID</constant></entry><entry>The security identifier (SID) of the primary group
				of the user.</entry></row>

				<row><entry><constant>sambaDomainName</constant></entry><entry>Domain the user is part of.</entry></row>
			</tbody>
			</tgroup></table>


			<para>
<indexterm><primary>PDC</primary></indexterm>
<indexterm><primary>sambaSamAccount</primary></indexterm>
			The majority of these parameters are only used when Samba is acting as a PDC of
			a domain (refer to <link linkend="samba-pdc">Domain Control</link>, for details on
			how to configure Samba as a PDC). The following four attributes
			are only stored with the sambaSamAccount entry if the values are non-default values:
			</para>

			<itemizedlist>
<indexterm><primary>sambaHomePath</primary></indexterm>
<indexterm><primary>sambaLogonScript</primary></indexterm>
<indexterm><primary>sambaProfilePath</primary></indexterm>
<indexterm><primary>sambaHomeDrive</primary></indexterm>
				<listitem><para>sambaHomePath</para></listitem>
				<listitem><para>sambaLogonScript</para></listitem>
				<listitem><para>sambaProfilePath</para></listitem>
				<listitem><para>sambaHomeDrive</para></listitem>
			</itemizedlist>

			<para>
<indexterm><primary>sambaSamAccount</primary></indexterm>
<indexterm><primary>PDC</primary></indexterm>
<indexterm><primary>smbHome</primary></indexterm>
			These attributes are only stored with the sambaSamAccount entry if
			the values are non-default values. For example, assume MORIA has now been
			configured as a PDC and that <smbconfoption name="logon home">\\%L\%u</smbconfoption> was defined in
			its &smb.conf; file. When a user named <quote>becky</quote> logs on to the domain,
			the <smbconfoption name="logon home"/> string is expanded to \\MORIA\becky.
			If the smbHome attribute exists in the entry <quote>uid=becky,ou=People,dc=samba,dc=org</quote>,
			this value is used. However, if this attribute does not exist, then the value
			of the <smbconfoption name="logon home"/> parameter is used in its place. Samba
			will only write the attribute value to the directory entry if the value is
			something other than the default (e.g., <filename>\\MOBY\becky</filename>).
			</para>

		</sect3>

		<sect3>
		<title>Example LDIF Entries for a sambaSamAccount</title>

			<para>
			The following is a working LDIF that demonstrates the use of the SambaSamAccount ObjectClass:
<programlisting>
dn: uid=guest2, ou=People,dc=quenya,dc=org
sambaLMPassword: 878D8014606CDA29677A44EFA1353FC7
sambaPwdMustChange: 2147483647
sambaPrimaryGroupSID: S-1-5-21-2447931902-1787058256-3961074038-513
sambaNTPassword: 552902031BEDE9EFAAD3B435B51404EE
sambaPwdLastSet: 1010179124
sambaLogonTime: 0
objectClass: sambaSamAccount
uid: guest2
sambaKickoffTime: 2147483647
sambaAcctFlags: [UX         ]
sambaLogoffTime: 2147483647
sambaSID: S-1-5-21-2447931902-1787058256-3961074038-5006
sambaPwdCanChange: 0
</programlisting>
			</para>

			<para>
			The following is an LDIF entry for using both the sambaSamAccount and
			posixAccount ObjectClasses:
<programlisting>
dn: uid=gcarter, ou=People,dc=quenya,dc=org
sambaLogonTime: 0
displayName: Gerald Carter
sambaLMPassword: 552902031BEDE9EFAAD3B435B51404EE
sambaPrimaryGroupSID: S-1-5-21-2447931902-1787058256-3961074038-1201
objectClass: posixAccount
objectClass: sambaSamAccount
sambaAcctFlags: [UX         ]
userPassword: {crypt}BpM2ej8Rkzogo
uid: gcarter
uidNumber: 9000
cn: Gerald Carter
loginShell: /bin/bash
logoffTime: 2147483647
gidNumber: 100
sambaKickoffTime: 2147483647
sambaPwdLastSet: 1010179230
sambaSID: S-1-5-21-2447931902-1787058256-3961074038-5004
homeDirectory: /home/moria/gcarter
sambaPwdCanChange: 0
sambaPwdMustChange: 2147483647
sambaNTPassword: 878D8014606CDA29677A44EFA1353FC7
</programlisting>
		</para>

		</sect3>

		<sect3>
		<title>Password Synchronization</title>

		<para>
		Samba-3 and later can update the non-Samba (LDAP) password stored with an account. When
		using pam_ldap, this allows changing both UNIX and Windows passwords at once.
		</para>

		<para>The <smbconfoption name="ldap passwd sync"/> options can have the  values shown in
		<link linkend="ldappwsync">Possible <emphasis>ldap passwd sync</emphasis> Values</link>.</para>

		<table frame="all" id="ldappwsync">
		<title>Possible <parameter>ldap passwd sync</parameter> Values</title>
		<tgroup cols="2">
			<colspec align="left" colwidth="1*"/>
			<colspec align="justify" colwidth="4*"/>
		<thead>
			<row><entry align="left">Value</entry><entry align="center">Description</entry></row>
		</thead>
		<tbody>
		<row><entry>yes</entry><entry><para>When the user changes his password, update
			       <constant>SambaNTPassword</constant>, <constant>SambaLMPassword</constant>,
			       and the <constant>password</constant> fields.</para></entry></row>

		<row><entry>no</entry><entry><para>Only update <constant>SambaNTPassword</constant> and
					<constant>SambaLMPassword</constant>.</para></entry></row>

		<row><entry>only</entry><entry><para>Only update the LDAP password and let the LDAP server
			worry about the other fields.  This option is only available on some LDAP servers and
			only when the LDAP server supports LDAP_EXOP_X_MODIFY_PASSWD.</para></entry></row>
		</tbody>
		</tgroup>
		</table>


		<para>More information can be found in the &smb.conf; man page.</para>

		</sect3>

		<sect3>
		<title>Using OpenLDAP Overlay for Password Syncronization</title>

		<para>
		Howard Chu has written a special overlay called <command>smbk5pwd</command>. This tool  modifies the
		<literal>SambaNTPassword</literal>, <literal>SambaLMPassword</literal> and <literal>Heimdal</literal>
		hashes in an OpenLDAP entry when an LDAP_EXOP_X_MODIFY_PASSWD operation is performed.
		</para>

		<para>
		The overlay is shipped with OpenLDAP-2.3 and can be found in the
		<filename>contrib/slapd-modules/smbk5pwd</filename> subdirectory. This module can also be used with
		OpenLDAP-2.2.
		</para>

		</sect3>

	</sect2>

</sect1>

<sect1>
<title>Common Errors</title>

	<sect2>
		<title>Users Cannot Logon</title>

		<para><quote>I've installed Samba, but now I can't log on with my UNIX account! </quote></para>

		<para>Make sure your user has been added to the current Samba <smbconfoption name="passdb backend"/>. 
		Read the <link linkend="acctmgmttools">Account Management Tools,</link> for details.</para>

	</sect2>

	<sect2>
	<title>Users Being Added to the Wrong Backend Database</title>

	<para>
	A few complaints have been received from users who just moved to Samba-3. The following
	&smb.conf; file entries were causing problems: new accounts were being added to the old
	smbpasswd file, not to the tdbsam passdb.tdb file:
	</para>

	<para>
	<smbconfblock>
	<smbconfsection name="[global]"/>
	<member>...</member>
	<smbconfoption name="passdb backend">smbpasswd, tdbsam</smbconfoption>
	<member>...</member>
	</smbconfblock>
	</para>

	<para>
	Samba will add new accounts to the first entry in the <emphasis>passdb backend</emphasis>
	parameter entry. If you want to update to the tdbsam, then change the entry to:
	</para>

	<para>
<smbconfblock>
[globals]
...
<smbconfoption name="passdb backend">tdbsam, smbpasswd</smbconfoption>
...
</smbconfblock>
	</para>

	</sect2>

	<sect2>
	<title>Configuration of <parameter>auth methods</parameter></title>

	<para>
	When explicitly setting an <smbconfoption name="auth methods"/> parameter,
	<parameter>guest</parameter> must be specified as the first entry on the line &smbmdash;
	for example, <smbconfoption name="auth methods">guest sam</smbconfoption>.
	</para>

	</sect2>

</sect1>

</chapter>