[nivanova/samba-autobuild/.git] / docs / docbook / projdoc / passdb.xml

<chapter id="passdb">
<chapterinfo>
        &author.jelmer;
        &author.jerry;
        &author.jeremy;
        &author.jht;
        <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>
Samba-3 implements a new capability to work concurrently with mulitple 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.
This chapter describes the new functionality and how to get the most out of it.
</para>

<para>
In the course of development of Samba-3 a number of requests were received to provide the
ability to migrate MS Windows NT4 SAM accounts to Samba-3 without the need to provide
matching Unix/Linux accounts. We called this the <emphasis>Non Unix Accounts (NUA)</emphasis>
capability. The intent was that an administrator could decide to use the <emphasis>tdbsam</emphasis>
backend and by simply specifying <emphasis>"passdb backedn = tdbsam_nua, guest"</emphasis>
this would allow Samba-3 to implement a solution that did not use Unix accounts per se. Late
in the development cycle the team doing this work hit upon some obstacles that prevents this
solution from being used. Given the delays with Samba-3 release a decision was made to NOT
deliver this functionality until a better method of recognising NT Group SIDs from NT User
SIDs could be found. This feature may thus return during the life cycle for the Samba-3 series.
</para>

<note><para>
Samba-3.0.0 does NOT support Non-Unix Account (NUA) operation.
</para></note>

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

<para>
Samba-3 provides for complete backwards compatibility with Samba-2.2.x functionality
as follows:
</para>

<variablelist>
<title>Backwards Compatibility Backends</title>
        <varlistentry><term>Plain Text:</term>
                <listitem>
                        <para>
                        This option uses nothing but the Unix/Linux <filename>/etc/passwd</filename>
                        style back end. On systems that have PAM (Pluggable Authentication Modules)
                        support all PAM modules are supported. The behaviour is just as it was with
                        Samba-2.2.x, and the protocol limitations imposed by MS Windows clients
                        apply likewise.
                        </para>
                </listitem>
        </varlistentry>

        <varlistentry><term>smbpasswd:</term>
                <listitem>
                        <para>
                        This option allows continues 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 needed to
                        provide the extended controls that are needed for more comprehensive 
                        interoperation with MS Windows NT4 / 200x servers.
                        </para>
                </listitem>
        </varlistentry>

        <varlistentry><term>ldapsam_compat (Samba-2.2 LDAP Compatibilty):</term>
                <listitem>
                        <para>
                        There is a password backend option that allows continued operation with
                        a 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.
                        </para>
                </listitem>
        </varlistentry>
</variablelist>

<para>
Samba-3 introduces the following new password backend capabilities:
</para>

<variablelist>
<title>New Backends</title>
        <varlistentry><term>tdbsam:</term>
                <listitem>
                        <para>
                        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 and MS Windows 200x based systems.
                        </para>

                        <para>
                        The inclusion of the <emphasis>tdbssam</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>
                        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>~samba/examples/LDAP</filename> directory.
                        </para>

                        <para>
                        The new LDAP implmentation significantly expands the control abilities that
                        were possible with prior versions of Samba. It is not possible to specify
                        "per user" 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 to allow greater scalability.
                        </para>
                </listitem>
        </varlistentry>

        <varlistentry><term>mysqlsam (MySQL based backend):</term>
                <listitem>
                        <para>
                        It is expected that the MySQL based SAM will be very popular in some corners.
                        This database backend will be on considerable interest to sites that want to
                        leverage existing MySQL technology.
                        </para>
                </listitem>
        </varlistentry>

        <varlistentry><term>xmlsam (XML based datafile):</term>
                <listitem>
                        <para>
                        Allows the account and password data to be stored in an XML format
                        data file. This backend is NOT recommended for normal operation, it is
                        provided for developmental and for experimental use only. We recognise
                        that this will not stop some people from using it anyhow, it should work
                        but is NOT officially supported at this time (and likely will not be
                        at any time).
                        </para>

                        <para>
                        The xmlsam option can be useful for account migration between database
                        backends. Use of this tool will allow the data to be edited before migration
                        into another backend format.
                        </para>
                </listitem>
        </varlistentry>

        <varlistentry><term>nisplussam:</term>
                <listitem>
                        <para>
                        The  NIS+ based passdb backend. Takes name NIS domain as an
                        optional argument. Only works with Sun NIS+ servers.
                        </para>
                </listitem>
        </varlistentry>

        <varlistentry><term>plugin:</term>
                <listitem>
                        <para>
                        This option allows any external non-Samba backend to interface directly
                        to the samba code. This facility will allow third part vendors to provide
                        a proprietary backend to Samba-3.
                        </para>
                </listitem>
        </varlistentry>
</variablelist>

</sect1>

<sect1>
        <title>Technical Information</title>

        <para>
        Old windows clients send plain text passwords over the wire. Samba can check these
        passwords by crypting them and comparing them to the hash stored in the unix user database.
        </para>
        
        <para>
        Newer windows clients send encrypted passwords (so-called Lanman and NT hashes) over 
        the wire, instead of plain text passwords. The newest clients will send only encrypted
        passwords and refuse to send plain text passwords, unless their registry is tweaked.
        </para>

        <para>
        These 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>
        In addition to differently encrypted passwords, windows also stores certain data for each
        user that is not stored in a unix user database. e.g: workstations the user may logon from,
        the location where the users' profile is stored, and so on. Samba retrieves and stores this
        information using a <parameter>passdb backend</parameter>.  Commonly available backends are LDAP, plain text
        file, MySQL and nisplus.  For more information, see the man page for &smb.conf; regarding the 
        <parameter>passdb backend</parameter> parameter.
        </para>

        <sect2>
        <title>Important Notes About Security</title>
                
                <para>
                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 cleartext 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 "password equivalent". 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 thus treat the data stored in whatever passdb
                backend you use (smbpasswd file, ldap, mysql) as though it contained the cleartext
                passwords of all your users. Its contents must be kept secret, and the file should
                be protected accordingly.
                </para>
                
                <para>
                Ideally we would like a password scheme that involves neither plain text passwords
                on the net nor on disk. Unfortunately this is not available as Samba is stuck with
                having to be compatible with other SMB systems (WinNT, WfWg, Win95 etc).
                </para>

                <para>
                Windows NT 4.0 Service pack 3 changed the default setting so that plaintext passwords
                are disabled from being sent over the wire. This mandates either the use of encrypted
                password support or edit the Windows NT registry to re-enable plaintext passwords.
                </para>
                
                <para>
                The following versions of MS 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 [se]
                        </para></listitem>

                        <listitem><para>
                        Windows Me</para>
                        </listitem>
                </itemizedlist>

                <note>
                <para>
                MS Windows XP Home does not have facilities to become a domain member and it can
                not 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>
                All current release 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 plain text _or_ encrypted password
                handling.
                </para>

                <para>
                MS Windows clients will cache the encrypted password alone. Where plain text passwords
                are re-enabled, through the appropriate registry change, the plain text 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
                affect a auto-reconnect. If the resource server does not support encrypted passwords the
                auto-reconnect will fail. <emphasis>USE OF ENCRYPTED PASSWORDS IS STRONGLY ADVISED.</emphasis>
                </para>

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

                        <itemizedlist>
                                <listitem><para>Plain text 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>Plain text passwords are not stored anywhere in
                                memory or on disk.</para></listitem>
                         
                                <listitem><para>WinNT doesn't 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 things you can do to stop this is to use SMB encryption.
                                </para></listitem>

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

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


                <sect3>
                <title>Advantages of non-encrypted passwords</title>

                        <itemizedlist>
                                <listitem><para>Plain text passwords are not kept 
                                on disk, and are NOT cached in memory. </para></listitem>
                                
                                <listitem><para>Uses same password file as other unix 
                                services such as login and ftp</para></listitem>
                                
                                <listitem><para>Use of other services (such as telnet and ftp) which
                                send plain text passwords over the net, so sending them for SMB
                                isn't such a big deal.</para></listitem>
                        </itemizedlist>
                </sect3>
        </sect2>

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

        <para>
        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>
        Firstly, all Samba SAM (Security Account Management database) accounts require
        a Unix/Linux UID that the account will map to. As users are added to the account
        information database samba-3 will call the <command>add user script</command>
        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>
        The second way to affect Windows SID to Unix UID mapping is via the
        <emphasis>idmap uid, 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 SAM server.
        </para>

        </sect2>
</sect1>

<sect1>
<title>Account Management Tools</title>

<para>
Samba-3 provides two (2) tools for management of User and machine accounts. These tools are
called <filename>smbpasswd</filename> and <filename>pdbedit</filename>. A third tool is under
development but is NOT expected to ship in time for Samba-3.0.0. The new tool will be a TCL/TK
GUI tool that looks much like the MS Windows NT4 Domain User Manager - hopefully this will
be announced in time for samba-3.0.1 release timing.
</para>
        <sect2>
        <title>The <emphasis>smbpasswd</emphasis> Command</title>
        
                <para>
                The smbpasswd utility is a utility similar to the <command>passwd</command>
                or <command>yppasswd</command> programs.  It maintains the two 32 byte password
                fields in the passdb backend.
                </para>

                <para>
                <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
                as follows:
                </para>

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

                <para>
                <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 interdomain trust accounts</emphasis>
                        </para></listitem>
                </itemizedlist>
                
                <para>
                To run smbpasswd as a normal user just type:
                </para>
                
                <para>
                <programlisting>
                <prompt>$ </prompt><userinput>smbpasswd</userinput>
                <prompt>Old SMB password: </prompt><userinput>&lt;secret&gt;</userinput>
                </programlisting>
                For <emphasis>secret</emphasis> type old value here - or hit return if
                there was no old password
                <programlisting>
                <prompt>New SMB Password: </prompt><userinput>&lt;new secret&gt;</userinput>
                <prompt>Repeat New SMB Password: </prompt><userinput>&lt;new secret&gt;</userinput>
                </programlisting>
                </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>
                When invoked by an ordinary user it will only allow change of their own
                SMB password.
                </para>
                
                <para>
                When run by root smbpasswd may take an optional argument, specifying
                the user name whose SMB password you wish to change. When run as root, smbpasswd
                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>
                <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>
                For more details on using <command>smbpasswd</command> refer to the man page (the
                definitive reference).
                </para>
        </sect2>

        <sect2>
        <title>The <emphasis>pdbedit</emphasis> Command</title>

                <para>
                <command>pdbedit</command> is a tool that can be used only by root. It is used to
                manage the passdb backend. <command>pdbedit</command> can be used to:
                </para>

                <itemizedlist>
                        <listitem><para>
                        add, remove or modify user accounts
                        </para></listitem>

                        <listitem><para>
                        listing user accounts
                        </para></listitem>

                        <listitem><para>
                        migrate user accounts
                        </para></listitem>
                </itemizedlist>

                <para>
                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 super set of them.
                </para>

                <para>
                One particularly important purpose of the <command>pdbedit</command> is to allow
                the migration of account information from one passdb backend to another. See the
                <link linkend="XMLpassdb">XML</link> password backend section of this chapter.
                </para>

                <para>
                The following is an example of the user account information that is stored in
                a tdbsam password backend. This listing was produced by running:
                </para>

                <para>
                pdbedit -Lv met
                <programlisting>
                Unix username:        met
                NT username:
                Account Flags:        [UX         ]
                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:               MIDEARTH
                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
                </programlisting>
                </para>

        </sect2>
</sect1>

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

<para>
Samba-3 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>
It is possible to specify not only multiple different password backends, but even multiple
backends of the same type. For example, to use two different tdbsam databases:
</para>

<para>
<programlisting>
In smb.conf [globals]
        passdb backend = tdbsam:/etc/samba/passdb.tdb, \
                tdbsam:/etc/samba/old-passdb.tdb, guest
</programlisting>
</para>


        <sect2>
        <title>Plain Text</title>

                <para>
                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 conduected via the way
                that the samba host OS will access it's <filename>/etc/passwd</filename> database.
                eg: On Linux systems that is done via PAM.
                </para>

        </sect2>

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

                <para>
                Traditionally, when configuring <ulink url="smb.conf.5.html#ENCRYPTPASSWORDS">"encrypt
                passwords = yes"</ulink> in Samba's <filename>smb.conf</filename> 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 very large numbers of users (counted
                in the thousands).
                </para>

                <itemizedlist>
                <listitem><para>
                The first is that all lookups must be performed sequentially.  Given that
                there are approximately two lookups per domain logon (one for a normal
                session connection 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 is used in databases.
                </para></listitem>

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

                <listitem><para>
                And finally, the amount of information which is stored in an smbpasswd entry leaves
                no room for additional attributes such as a home directory, password expiration time,
                or even a Relative Identified (RID).
                </para></listitem>
                </itemizedlist>

                <para>
                As a result of these defeciencies, a more robust means of storing user attributes
                used by smbd was developed.  The API which 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 CVS trees). 
                </para>

                <para>
                Samba-3 provides an enhanced set of passdb backends that overcome the deficiencies
                of the smbpasswd plain text database. These are tdbsam, ldapsam, and xmlsam.
                Of these ldapsam will be of most interest to large corporate or enterprise sites.
                </para>

        </sect2>

        <sect2>
        <title>tdbsam</title>

                <para>Samba can store user and machine account data in a "TDB" (Trivial Database).
                Using this backend doesn't require any additional configuration. This backend is
                recommended for new installations that do not require LDAP.
                </para>

                <para>
                As a general guide the Samba-Team do 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 implmentations that requires replication of the account
                database. Clearly, for reason of scalability the use of ldapsam should be encouraged.
                </para>

        </sect2>

        <sect2>
        <title>ldapsam</title>

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

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

                <para>
                The second item can be accomplished by using LDAP NSS and PAM modules.  LGPL
                versions of these libraries can be obtained from PADL Software
                (<ulink url="http://www.padl.com/">http://www.padl.com/</ulink>). More
                information about the configuration of these packages may be found at "LDAP,
                System Administration; Gerald Carter, O'Reilly; Chapter 6: Replacing NIS".
                Refer to <ulink url="http://safari.oreilly.com/?XmlId=1-56592-491-6">
                http://safari.oreilly.com/?XmlId=1-56592-491-6</ulink> for those who might wish to know
                more about configuration and adminstration of an OpenLDAP server.
                </para>

                <para>
                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>OpenLDAP - <ulink url="http://www.openldap.org/">http://www.openldap.org/</ulink></para></listitem>
                        <listitem><para>iPlanet Directory Server -
                         <ulink url="http://iplanet.netscape.com/directory">http://iplanet.netscape.com/directory</ulink></para></listitem>
                </itemizedlist>

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

                <itemizedlist>
                        <listitem><para>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>The NT migration scripts from <ulink url="http://samba.idealx.org/">IDEALX</ulink> that are
                        geared to manage users and group in such a Samba-LDAP Domain Controller configuration.
                        </para></listitem>
                </itemizedlist>

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

                        <para>
                        The LDAP ldapsam code has been developed and tested using the OpenLDAP 2.0 and 2.1 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 <link linkend="bugreport">Bug reporting facility</link>.
                        </para>

                </sect3>

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


                        <para>
                        Samba 3.0 includes the necessary schema file for OpenLDAP 2.0 in
                        <filename>examples/LDAP/samba.schema</filename>.  The sambaAccount objectclass is given here:
                        </para>

<para>
<programlisting>
objectclass ( 1.3.6.1.4.1.7165.2.2.3 NAME 'sambaAccount' SUP top AUXILIARY
    DESC 'Samba Auxilary Account'
    MUST ( uid $ rid )
    MAY  ( cn $ lmPassword $ ntPassword $ pwdLastSet $ logonTime $
           logoffTime $ kickoffTime $ pwdCanChange $ pwdMustChange $ acctFlags $
           displayName $ smbHome $ homeDrive $ scriptPath $ profilePath $
           description $ userWorkstations $ primaryGroupID $ domain ))
</programlisting>
</para>

                        <para>
                        The <filename>samba.schema</filename> file has been formatted for OpenLDAP 2.0/2.1.
                        The OID's are owned by the Samba Team and as such is legal to be openly published.
                        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>
                        Just as the smbpasswd file is meant to store information which supplements a
                        user's <filename>/etc/passwd</filename> entry, so is the sambaAccount object
                        meant to supplement the UNIX user account information.  A sambaAccount is a
                        <constant>STRUCTURAL</constant> objectclass so it can be stored individually
                        in the directory.  However, there are several fields (e.g. uid) which overlap
                        with the posixAccount objectclass outlined in RFC2307.  This is by design.
                        </para>

                        <!--olem: we should perhaps have a note about shadowAccounts too as many
                        systems use them, isn'it ? -->

                        <para>
                        In order to store all user account information (UNIX and Samba) in the directory,
                        it is necessary to use the sambaAccount and posixAccount objectclasses in
                        combination.  However, smbd will still obtain the user's UNIX account
                        information via the standard C library calls (e.g. getpwnam(), et. al.).
                        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>
                        To include support for the sambaAccount 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.
                        </para>

<para>
<screen>
&rootprompt;<userinput>cp samba.schema /etc/openldap/schema/</userinput>
</screen>
</para>

                        <para>
                        Next, include the <filename>samba.schema</filename> file in <filename>slapd.conf</filename>.
                        The sambaAccount object contains two attributes which depend upon other schema
                        files.  The 'uid' attribute is defined in <filename>cosine.schema</filename> and
                        the 'displayName' attribute is defined in the <filename>inetorgperson.schema</filename>
                        file.  Both of these must be included before the <filename>samba.schema</filename> file.
                        </para>

<para>
<programlisting>
## /etc/openldap/slapd.conf

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

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

                <para>
                It is recommended that you maintain some indices on some of the most usefull attributes,
                like in the following example, to speed up searches made on sambaAccount objectclasses
                (and possibly posixAccount and posixGroup as well).
                </para>

<para>
<screen>
# 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
</screen>
</para>

                <para>
                Create the new index by executing:
                </para>

<para>
<screen>
./sbin/slapindex -f slapd.conf
</screen>
</para>

                <para>
                Remember to restart slapd after making these changes:
                </para>

<para>
<screen>
&rootprompt;<userinput>/etc/init.d/slapd restart</userinput>
</screen>
</para>

                </sect3>

                <sect3>
                <title>Initialise the LDAP database</title>

                <para>
                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 (ie: Your DNS entries, etc.).
                </para>
                
<para>
<screen>
# Organization for Samba Base
dn: dc=plainjoe,dc=org
objectclass: dbObject
objectclass: organization
dc: plainjoe
o: Terpstra Org Network
description: The Samba-3 Network LDAP Example

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

# Setting up container for users
dn: ou=People,dc=plainjoe,dc=org
objectclass: top
objectclass: organizationalUnit
ou: People

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

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

                <para>
                The following command will then load the contents of the LDIF file into the LDAP
                database.
                </para>

<para>
<screen>
slapadd -v -l initldap.dif
</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>
                Before Samba can access the LDAP server you need to stoe the LDAP admin password
                into the Samba-3 <filename>secrets.tdb</filename> database by:
                <screen>
                &rootprompt; <command>smbpasswd -w secret</command>
                </screen>
                </para>
                </note>

                </sect3>

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

                        <para>
                        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.
                        </para>

                <itemizedlist>
                        <listitem><para><ulink url="smb.conf.5.html#PASSDBBACKEND">passdb backend = ldapsam:url</ulink></para></listitem>
                        <listitem><para><ulink url="smb.conf.5.html#LDAPSSL">ldap ssl</ulink></para></listitem>
                        <listitem><para><ulink url="smb.conf.5.html#LDAPADMINDN">ldap admin dn</ulink></para></listitem>
                        <listitem><para><ulink url="smb.conf.5.html#LDAPSUFFIX">ldap suffix</ulink></para></listitem>
                        <listitem><para><ulink url="smb.conf.5.html#LDAPFILTER">ldap filter</ulink></para></listitem>
                        <listitem><para><ulink url="smb.conf.5.html#LDAPMACHINSUFFIX">ldap machine suffix</ulink></para></listitem>
                        <listitem><para><ulink url="smb.conf.5.html#LDAPUSERSUFFIX">ldap user suffix</ulink></para></listitem>
                        <listitem><para><ulink url="smb.conf.5.html#LDAPDELETEDN">ldap delete dn</ulink></para></listitem>
                        <listitem><para><ulink url="smb.conf.5.html#LDAPPASSWDSYNC">ldap passwd sync</ulink></para></listitem>
                        <listitem><para><ulink url="smb.conf.5.html#LDAPTRUSTIDS">ldap trust ids</ulink></para></listitem>

                </itemizedlist>

                        <para>
                        These are described in the &smb.conf; man
                        page and so will not be repeated here.  However, a sample smb.conf file for
                        use with an LDAP directory could appear as
                        </para>

<para>
<screen>
## /usr/local/samba/lib/smb.conf
[global]
     security = user
     encrypt passwords = yes

     netbios name = TASHTEGO
     workgroup = NARNIA

     # ldap related parameters

     # define the DN to use when binding to the directory servers
     # The password for this DN is not stored in smb.conf.  Rather it
     # must be set by using 'smbpasswd -w <replaceable>secretpw</replaceable>' to store the
     # passphrase in the secrets.tdb file.  If the "ldap admin dn" values
     # change, this password will need to be reset.
     ldap admin dn = "cn=Samba Manager,ou=people,dc=samba,dc=org"

     # Define the SSL option when connecting to the directory
     # ('off', 'start tls', or 'on' (default))
     ldap ssl = start tls

     # syntax: passdb backend = ldapsam:ldap://server-name[:port]
     passdb backend = ldapsam:ldap://funball.samba.org, guest

     # smbpasswd -x delete the entire dn-entry
     ldap delete dn = no

     # the machine and user suffix added to the base suffix
     # wrote WITHOUT quotes. NULL siffixes by default
     ldap user suffix = ou=People
     ldap machine suffix = ou=Systems

     # Trust unix account information in LDAP
     #  (see the smb.conf manpage for details)
     ldap trust ids = Yes

     # specify the base DN to use when searching the directory
     ldap suffix = "ou=people,dc=samba,dc=org"

     # generally the default ldap search filter is ok
     # ldap filter = "(&amp;(uid=%u)(objectclass=sambaAccount))"
</screen>
</para>

                </sect3>

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

                        <para>
                        As users accounts are managed thru the sambaAccount objectclass, you should
                        modify your existing administration tools to deal with sambaAccount attributes.
                        </para>

                        <para>
                        Machines accounts are managed with the sambaAccount objectclass, just
                        like users accounts. However, it's up to you to store thoses accounts
                        in a different tree of your LDAP namespace: you should use
                        "ou=Groups,dc=plainjoe,dc=org" to store groups and
                        "ou=People,dc=plainjoe,dc=org" to store users. Just configure your
                        NSS and PAM accordingly (usually, in the /etc/ldap.conf configuration
                        file).
                        </para>

                        <para>
                        In Samba release 3.0, the group management system is based on posix
                        groups. This means that Samba makes usage of the posixGroup objectclass.
                        For now, there is no NT-like group system management (global and local
                        groups).
                        </para>

                </sect3>

                <sect3>
                <title>Security and sambaAccount</title>


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

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

                        <para>
                        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 the
                        <link linkend="passdb">Account Information Database</link> section of this chapter.
                        </para>

                        <para>
                        To remedy the first security issue, the "ldap ssl" smb.conf parameter defaults
                        to require an encrypted session (<parameter>ldap ssl = on</parameter>) using
                        the default port of <constant>636</constant>
                        when contacting the directory server.  When using an OpenLDAP server, it
                        is possible to use the use the StartTLS LDAP extended  operation in the place of
                        LDAPS.  In either case, you are strongly discouraged to disable this security
                        (<parameter>ldap ssl = off</parameter>).
                        </para>

                        <para>
                        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>
                        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>
<screen>
## allow the "ldap admin dn" access, but deny everyone else
access to attrs=lmPassword,ntPassword
     by dn="cn=Samba Admin,ou=people,dc=plainjoe,dc=org" write
     by * none
</screen>
</para>

                </sect3>

                <sect3>
                <title>LDAP special attributes for sambaAccounts</title>

                        <para>
                        The sambaAccount objectclass is composed of the following attributes:
                        </para>

                        <itemizedlist>
                                <listitem><para><constant>lmPassword</constant>: the LANMAN password 16-byte hash stored as a character
                                representation of a hexidecimal string.</para></listitem>

                                <listitem><para><constant>ntPassword</constant>: the NT password hash 16-byte stored as a character
                                representation of a hexidecimal string.</para></listitem>

                                <listitem><para><constant>pwdLastSet</constant>: The integer time in seconds since 1970 when the
                                <constant>lmPassword</constant> and <constant>ntPassword</constant> attributes were last set.
                                </para></listitem>

                                <listitem><para><constant>acctFlags</constant>: 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).</para></listitem>

                                <listitem><para><constant>logonTime</constant>: Integer value currently unused</para></listitem>

                                <listitem><para><constant>logoffTime</constant>: Integer value currently unused</para></listitem>

                                <listitem><para><constant>kickoffTime</constant>: Integer value currently unused</para></listitem>

                                <listitem><para><constant>pwdCanChange</constant>: Integer value currently unused</para></listitem>

                                <listitem><para><constant>pwdMustChange</constant>: Integer value currently unused</para></listitem>

                                <listitem><para><constant>homeDrive</constant>: specifies the drive letter to which to map the
                                UNC path specified by homeDirectory. The drive letter must be specified in the form "X:"
                                where X is the letter of the drive to map. Refer to the "logon drive" parameter in the
                                smb.conf(5) man page for more information.</para></listitem>

                                <listitem><para><constant>scriptPath</constant>: The scriptPath 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 "logon script" parameter in the
                                smb.conf(5) man page for more information.</para></listitem>

                                <listitem><para><constant>profilePath</constant>: 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
                                "logon path" parameter in the smb.conf(5) man page for more information.</para></listitem>

                                <listitem><para><constant>smbHome</constant>: The homeDirectory property specifies the path of
                                the home directory for the user. The string can be null. If homeDrive is set and specifies
                                a drive letter, homeDirectory 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.
                                </para></listitem>

                                <listitem><para><constant>userWorkstation</constant>: character string value currently unused.
                                </para></listitem>

                                <listitem><para><constant>rid</constant>: the integer representation of the user's relative identifier
                                (RID).</para></listitem>

                                <listitem><para><constant>primaryGroupID</constant>: the relative identifier (RID) of the primary group
                                of the user.</para></listitem>

                                <listitem><para><constant>domain</constant>: domain the user is part of.</para></listitem>
                        </itemizedlist>

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

                        <itemizedlist>
                                <listitem><para>smbHome</para></listitem>
                                <listitem><para>scriptPath</para></listitem>
                                <listitem><para>logonPath</para></listitem>
                                <listitem><para>homeDrive</para></listitem>
                        </itemizedlist>

                        <para>
                        These attributes are only stored with the sambaAccount entry if
                        the values are non-default values.  For example, assume TASHTEGO has now been
                        configured as a PDC and that <command>logon home = \\%L\%u</command> was defined in
                        its <filename>smb.conf</filename> file. When a user named "becky" logons to the domain,
                        the <parameter>logon home</parameter> string is expanded to \\TASHTEGO\becky.
                        If the smbHome attribute exists in the entry "uid=becky,ou=people,dc=samba,dc=org",
                        this value is used.  However, if this attribute does not exist, then the value
                        of the <parameter>logon home</parameter> 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 sambaAccount</title>

                        <para>
                        The following is a working LDIF with the inclusion of the posixAccount objectclass:
                        </para>

        <para>
        <screen>
        dn: uid=guest2, ou=people,dc=plainjoe,dc=org
        ntPassword: 878D8014606CDA29677A44EFA1353FC7
        pwdMustChange: 2147483647
        primaryGroupID: 1201
        lmPassword: 552902031BEDE9EFAAD3B435B51404EE
        pwdLastSet: 1010179124
        logonTime: 0
        objectClass: sambaAccount
        uid: guest2
        kickoffTime: 2147483647
        acctFlags: [UX         ]
        logoffTime: 2147483647
        rid: 19006
        pwdCanChange: 0
        </screen>
        </para>

                        <para>
                        The following is an LDIF entry for using both the sambaAccount and
                        posixAccount objectclasses:
                        </para>

        <para>
        <screen>
        dn: uid=gcarter, ou=people,dc=plainjoe,dc=org
        logonTime: 0
        displayName: Gerald Carter
        lmPassword: 552902031BEDE9EFAAD3B435B51404EE
        primaryGroupID: 1201
        objectClass: posixAccount
        objectClass: sambaAccount
        acctFlags: [UX         ]
        userPassword: {crypt}BpM2ej8Rkzogo
        uid: gcarter
        uidNumber: 9000
        cn: Gerald Carter
        loginShell: /bin/bash
        logoffTime: 2147483647
        gidNumber: 100
        kickoffTime: 2147483647
        pwdLastSet: 1010179230
        rid: 19000
        homeDirectory: /home/tashtego/gcarter
        pwdCanChange: 0
        pwdMustChange: 2147483647
        ntPassword: 878D8014606CDA29677A44EFA1353FC7
        </screen>
        </para>

                </sect3>

                <sect3>
                <title>Password synchronisation</title>

                <para>
                Since version 3.0 samba 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 <command>ldap passwd sync</command> options can have the following values:</para>

                <variablelist>
                       <varlistentry>
                               <term>yes</term>
                               <listitem><para>When the user changes his password, update
                                               <constant>ntPassword</constant>, <constant>lmPassword</constant>
                                               and the <constant>password</constant> fields.</para></listitem>
                       </varlistentry>

                       <varlistentry>
                               <term>no</term>
                               <listitem><para>Only update <constant>ntPassword</constant> and <constant>lmPassword</constant>.</para></listitem>
                       </varlistentry>

                       <varlistentry>
                               <term>only</term>
                               <listitem><para>Only update the LDAP password and let the LDAP server worry
                                               about the other fields. This option is only available when
                                               the LDAP library supports LDAP_EXOP_X_MODIFY_PASSWD. </para></listitem>
                       </varlistentry>
                </variablelist>

                <para>More information can be found in the <ulink url="smb.conf.5.html#LDAPPASSWDSYNC">smb.conf</ulink> manpage.
                </para>

                </sect3>

                <sect3>
                <title>ldap trust ids</title>

                <para>
                LDAP Performance can be improved by using the <command>ldap trust ids</command> parameter.
                See the <ulink url="smb.conf.5.html#LDAPTRUSTIDS">smb.conf</ulink> manpage for details.
                </para>

                </sect3>

        </sect2>

        <sect2>
        <title>MySQL</title>

        <para>
        Every so often someone will come along with a great new idea. Storing of user accounts in an
        SQL backend is one of them. Those who want to do this are in the best position to know what the
        specific benefits are to them. This may sound like a cop-out, but in truth we can not attempt
        to document every nitty little detail why certain things of marginal utility to the bulk of
        Samba users might make sense to the rest. In any case, the following instructions should help
        the determined SQL user to implement a working system.
        </para>

                <sect3>
                <title>Creating the database</title>

                        <para>
                        You either can set up your own table and specify the field names to pdb_mysql (see below
                        for the column names) or use the default table. The file <filename>examples/pdb/mysql/mysql.dump</filename> 
                        contains the correct queries to create the required tables. Use the command :

                        <screen>
                        <command>mysql -u<replaceable>username</replaceable> -h<replaceable>hostname</replaceable> -p<replaceable>password</replaceable> <replaceable>databasename</replaceable> &gt; <filename>/path/to/samba/examples/pdb/mysql/mysql.dump</filename></command>
                        </screen>
                        </para>
                </sect3>

                <sect3>
                <title>Configuring</title>

                        <para>This plugin lacks some good documentation, but here is some short info:</para>

                        <para>Add a the following to the <command>passdb backend</command> variable in your <filename>smb.conf</filename>:
                        <screen>
                        passdb backend = [other-plugins] mysql:identifier [other-plugins]
                        </screen>
                        </para>

                        <para>The identifier can be any string you like, as long as it doesn't collide with 
                        the identifiers of other plugins or other instances of pdb_mysql. If you 
                        specify multiple pdb_mysql.so entries in <parameter>passdb backend</parameter>, you also need to 
                        use different identifiers!
                        </para>

                        <para>
                                Additional options can be given thru the &smb.conf; file in the <command>[global]</command> section.
                        </para>

                <para>
                <screen>
                identifier:mysql host                     - host name, defaults to 'localhost'
                identifier:mysql password
                identifier:mysql user                     - defaults to 'samba'
                identifier:mysql database                 - defaults to 'samba'
                identifier:mysql port                     - defaults to 3306
                identifier:table                          - Name of the table containing users
                </screen>
                </para>

                        <warning>
                        <para>
                        Since the password for the mysql user is stored in the 
                        &smb.conf; file, you should make the the &smb.conf; file 
                        readable only to the user that runs samba. This is considered a security 
                        bug and will be fixed soon.
                        </para>
                        </warning>

                        <para>Names of the columns in this table(I've added column types those columns should have first):</para>

                <para>
                <screen>
                identifier:logon time column             - int(9)
                identifier:logoff time column            - int(9)
                identifier:kickoff time column           - int(9)
                identifier:pass last set time column     - int(9)
                identifier:pass can change time column   - int(9)
                identifier:pass must change time column  - int(9)
                identifier:username column               - varchar(255) - unix username
                identifier:domain column                 - varchar(255) - NT domain user is part of
                identifier:nt username column            - varchar(255) - NT username
                identifier:fullname column               - varchar(255) - Full name of user
                identifier:home dir column               - varchar(255) - Unix homedir path
                identifier:dir drive column              - varchar(2)   - Directory drive path (eg: 'H:')
                identifier:logon script column           - varchar(255)
                                                         - Batch file to run on client side when logging on
                identifier:profile path column           - varchar(255) - Path of profile
                identifier:acct desc column              - varchar(255) - Some ASCII NT user data
                identifier:workstations column           - varchar(255)
                                                         - Workstations user can logon to (or NULL for all)
                identifier:unknown string column         - varchar(255) - unknown string
                identifier:munged dial column            - varchar(255) - ?
                identifier:user sid column               - varchar(255) - NT user SID
                identifier:group sid column              - varchar(255) - NT group ID
                identifier:lanman pass column            - varchar(255) - encrypted lanman password
                identifier:nt pass column                - varchar(255) - encrypted nt passwd
                identifier:plain pass column             - varchar(255) - plaintext password
                identifier:acct control column           - int(9) - nt user data
                identifier:unknown 3 column              - int(9) - unknown
                identifier:logon divs column             - int(9) - ?
                identifier:hours len column              - int(9) - ?
                identifier:unknown 5 column              - int(9) - unknown
                identifier:unknown 6 column              - int(9) - unknown
                </screen>
                </para>

                        <para>
                        Eventually, you can put a colon (:) after the name of each column, which 
                        should specify the column to update when updating the table. You can also
                        specify nothing behind the colon - then the data from the field will not be 
                        updated. 
                        </para>

                </sect3>

                <sect3>
                <title>Using plaintext passwords or encrypted password</title>

                        <para>
                        I strongly discourage the use of plaintext passwords, however, you can use them:
                        </para>

                        <para>
                        If you would like to use plaintext passwords, set
                        'identifier:lanman pass column' and 'identifier:nt pass column' to
                        'NULL' (without the quotes) and 'identifier:plain pass column' to the
                        name of the column containing the plaintext passwords. 
                        </para>

                        <para>
                        If you use encrypted passwords, set the 'identifier:plain pass
                        column' to 'NULL' (without the quotes). This is the default.
                        </para>

                </sect3>

                <sect3>
                <title>Getting non-column data from the table</title>

                        <para>
                        It is possible to have not all data in the database and making some 'constant'.
                        </para>

                        <para>
                        For example, you can set 'identifier:fullname column' to : 
                        <command>CONCAT(First_name,' ',Sur_name)</command>
                        </para>

                        <para>
                        Or, set 'identifier:workstations column' to :
                        <command>NULL</command></para>

                        <para>See the MySQL documentation for more language constructs.</para>

                </sect3>
        </sect2>

        <sect2 id="XMLpassdb">
        <title>XML</title>

                <para>This module requires libxml2 to be installed.</para>

                <para>The usage of pdb_xml is pretty straightforward. To export data, use:
                </para>

                <para>
                        <userinput>pdbedit -e xml:filename</userinput>
                </para>

                <para>
                (where filename is the name of the file to put the data in)
                </para>

                <para>
                To import data, use:
                <userinput>pdbedit -i xml:filename -e current-pdb</userinput>
                </para>

                <para>
                Where filename is the name to read the data from and current-pdb to put it in.
                </para>

                <para>
                For example: To migrate (copy) the smbpasswd database into a tdbsam database:
                </para>

                <para>
                then execute (as root):
                <screen>
                &rootprompt;<userinput>pdbedit -i smbpasswd -e tdbsam</userinput>
                </screen>
                </para>
        </sect2>
</sect1>

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

        <sect2>
        <title>Users can not logon - Users not in Samba SAM</title>

        <para>
        People forget to put their users in their backend and then complain samba won't authorize them.
        </para>

        </sect2>

        <sect2>
        <title>Users are being added to the wrong backend database</title>

        <para>
        A few complaints have been recieved from users that 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>
        <screen>
        [globals]
                ...
                passdb backend = smbpasswd, tdbsam, guest
                ...
        </screen>
        </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>
        <screen>
        [globals]
                ...
                passdb backend = tdbsam, smbpasswd, guest
                ...
        </screen>
        </para>

        </sect2>
</sect1>
</chapter>