summaryrefslogtreecommitdiff
path: root/docs/howto/DOMAIN_MEMBER.xml
diff options
context:
space:
mode:
Diffstat (limited to 'docs/howto/DOMAIN_MEMBER.xml')
-rw-r--r--docs/howto/DOMAIN_MEMBER.xml1105
1 files changed, 1105 insertions, 0 deletions
diff --git a/docs/howto/DOMAIN_MEMBER.xml b/docs/howto/DOMAIN_MEMBER.xml
new file mode 100644
index 0000000000..72b00663f7
--- /dev/null
+++ b/docs/howto/DOMAIN_MEMBER.xml
@@ -0,0 +1,1105 @@
+<chapter id="domain-member">
+
+<chapterinfo>
+ &author.jht;
+ &author.jeremy;
+ &author.jerry;
+ &author.tridge;
+ &author.jelmer;
+ <author>&person.gd;<contrib>LDAP updates</contrib></author>
+</chapterinfo>
+
+<title>Domain Membership</title>
+
+<para>
+Domain Membership is a subject of vital concern. Samba must be able to
+participate as a member server in a Microsoft Domain Security context, and
+Samba must be capable of providing Domain machine member trust accounts,
+otherwise it would not be able to offer a viable option for many users.
+</para>
+
+<para>
+This chapter covers background information pertaining to Domain Membership,
+the Samba configuration for it, and MS Windows client procedures for joining a
+domain. Why is this necessary? Because both are areas in which there exists
+within the current MS Windows networking world and particularly in the
+UNIX/Linux networking and administration world, a considerable level of
+misinformation, incorrect understanding and a lack of knowledge. Hopefully
+this chapter will fill the voids.
+</para>
+
+<sect1>
+<title>Features and Benefits</title>
+
+<para>
+MS Windows workstations and servers that want to participate in Domain Security need to
+be made Domain Members. Participating in Domain Security is often called
+<emphasis>Single Sign On</emphasis> or <acronym>SSO</acronym> for short. This
+chapter describes the process that must be followed to make a workstation
+(or another server &smbmdash; be it an <application>MS Windows NT4 / 200x</application>
+server) or a Samba server a member of an MS Windows Domain Security context.
+</para>
+
+<para>
+<indexterm><primary>Server Type</primary><secondary>Domain Member</secondary></indexterm>
+Samba-3 can join an MS Windows NT4-style domain as a native member server, an
+MS Windows Active Directory Domain as a native member server, or a Samba Domain
+Control network. Domain Membership has many advantages:
+</para>
+
+<itemizedlist>
+ <listitem><para>
+<indexterm><primary>SAM</primary></indexterm>
+ MS Windows workstation users get the benefit of SSO.
+ </para></listitem>
+
+ <listitem><para>
+ Domain user access rights and file ownership/access controls can be set
+ from the single Domain Security Account Manager (SAM) database
+ (works with Domain Member servers as well as with MS Windows workstations
+ that are Domain Members).
+ </para></listitem>
+
+ <listitem><para>
+ Only <application>MS Windows NT4/200x/XP Professional</application>
+ workstations that are Domain Members can use network logon facilities.
+ </para></listitem>
+
+ <listitem><para>
+ Domain Member workstations can be better controlled through the use of
+ Policy files (<filename>NTConfig.POL</filename>) and Desktop Profiles.
+ </para></listitem>
+
+ <listitem><para>
+ Through the use of logon scripts, users can be given transparent access to network
+ applications that run off application servers.
+ </para></listitem>
+
+ <listitem><para>
+ Network administrators gain better application and user access management
+ abilities because there is no need to maintain user accounts on any network
+ client or server, other than the central Domain database
+ (either NT4/Samba SAM style Domain, NT4 Domain that is backend-ed with an
+ LDAP directory, or via an Active Directory infrastructure).
+ </para></listitem>
+</itemizedlist>
+
+</sect1>
+
+<sect1 id="machine-trust-accounts">
+<title>MS Windows Workstation/Server Machine Trust Accounts</title>
+
+<para>
+<indexterm><primary>Machine Trust Accounts</primary></indexterm>
+A Machine Trust Account is an account that is used to authenticate a client
+machine (rather than a user) to the Domain Controller server. In Windows terminology,
+this is known as a <quote>Computer Account.</quote> The purpose of the machine account
+is to prevent a rogue user and Domain Controller from colluding to gain access to a
+domain member workstation.
+</para>
+
+<para>
+The password of a Machine Trust Account acts as the shared secret for
+secure communication with the Domain Controller. This is a security
+feature to prevent an unauthorized machine with the same NetBIOS name
+from joining the domain and gaining access to domain user/group
+accounts. Windows NT/200x/XP Professional clients use machine trust
+accounts, but Windows 9x/Me/XP Home clients do not. Hence, a
+Windows 9x/Me/XP Home client is never a true member of a Domain
+because it does not possess a Machine Trust Account, and, thus, has no
+shared secret with the Domain Controller.
+</para>
+
+<para>
+A Windows NT4 PDC stores each Machine Trust Account in the Windows Registry.
+The introduction of MS Windows 2000 saw the introduction of Active Directory,
+the new repository for Machine Trust Accounts. A Samba PDC, however, stores
+each Machine Trust Account in two parts,
+as follows:
+
+<itemizedlist>
+ <listitem><para>
+ A Domain Security Account (stored in the
+ <smbconfoption><name>passdb backend</name></smbconfoption> that has been configured in the
+ &smb.conf; file. The precise nature of the account information that is
+ stored depends on the type of backend database that has been chosen.
+ </para>
+
+ <para>
+ The older format of this data is the <filename>smbpasswd</filename> database
+ that contains the UNIX login ID, the UNIX user identifier (UID), and the
+ LanMan and NT encrypted passwords. There is also some other information in
+ this file that we do not need to concern ourselves with here.
+ </para>
+
+ <para>
+ The two newer database types are called ldapsam, and
+ tdbsam. Both store considerably more data than the
+ older <filename>smbpasswd</filename> file did. The extra information
+ enables new user account controls to be implemented.
+ </para></listitem>
+
+ <listitem><para>
+ A corresponding UNIX account, typically stored in
+ <filename>/etc/passwd</filename>. Work is in progress to allow a
+ simplified mode of operation that does not require UNIX user accounts, but
+ this may not be a feature of the early releases of Samba-3.
+ </para></listitem>
+</itemizedlist>
+</para>
+
+<para>
+<indexterm><primary>Machine Trust Accounts</primary><secondary>creating</secondary></indexterm>
+There are three ways to create Machine Trust Accounts:
+</para>
+
+<itemizedlist>
+ <listitem><para>
+ Manual creation from the UNIX/Linux command line. Here, both the Samba and
+ corresponding UNIX account are created by hand.
+ </para></listitem>
+
+ <listitem><para>
+ <indexterm><primary>Server Manager</primary></indexterm>
+ Using the MS Windows NT4 Server Manager, either from an NT4 Domain Member
+ server, or using the Nexus toolkit available from the Microsoft Web site.
+ This tool can be run from any MS Windows machine as long as the user is
+ logged on as the administrator account.
+ </para></listitem>
+
+ <listitem><para>
+ <quote>On-the-fly</quote> creation. The Samba Machine Trust Account is automatically
+ created by Samba at the time the client is joined to the domain.
+ (For security, this is the recommended method.) The corresponding UNIX
+ account may be created automatically or manually.
+ </para></listitem>
+</itemizedlist>
+
+<sect2>
+<title>Manual Creation of Machine Trust Accounts</title>
+
+<para>
+The first step in manually creating a Machine Trust Account is to manually
+create the corresponding UNIX account in <filename>/etc/passwd</filename>.
+This can be done using <command>vipw</command> or another <quote>add user</quote> command
+that is normally used to create new UNIX accounts. The following is an example for
+a Linux-based Samba server:
+</para>
+
+<para>
+<indexterm><primary>useradd</primary></indexterm>
+<indexterm><primary>vipw</primary></indexterm>
+<screen>
+&rootprompt;<userinput>/usr/sbin/useradd -g machines -d /dev/null -c <replaceable>"machine nickname"</replaceable> \
+ -s /bin/false <replaceable>machine_name</replaceable>$ </userinput>
+
+&rootprompt;<userinput>passwd -l <replaceable>machine_name</replaceable>$</userinput>
+</screen>
+</para>
+
+<para>In the above example above there is an existing system group <quote>machines</quote> which is used
+as the primary group for all machine accounts. In the following examples the <quote>machines</quote> group has
+numeric GID equal 100.</para>
+
+<para>
+<indexterm><primary>chpass</primary></indexterm>
+On *BSD systems, this can be done using the <command>chpass</command> utility:
+</para>
+
+<para>
+<screen>
+&rootprompt;<userinput>chpass -a \
+'<replaceable>machine_name</replaceable>$:*:101:100::0:0:Windows <replaceable>machine_name</replaceable>:/dev/null:/sbin/nologin'</userinput>
+</screen>
+</para>
+
+<para>
+The <filename>/etc/passwd</filename> entry will list the machine name
+with a <quote>$</quote> appended, will not have a password, will have a null shell and no
+home directory. For example, a machine named <quote>doppy</quote> would have an
+<filename>/etc/passwd</filename> entry like this:
+</para>
+
+<programlisting>
+doppy$:x:505:100:<replaceable>machine_nickname</replaceable>:/dev/null:/bin/false
+</programlisting>
+
+<para>
+Above, <replaceable>machine_nickname</replaceable> can be any
+descriptive name for the client, i.e., BasementComputer.
+<replaceable>machine_name</replaceable> absolutely must be the NetBIOS
+name of the client to be joined to the domain. The <quote>$</quote> must be
+appended to the NetBIOS name of the client or Samba will not recognize
+this as a Machine Trust Account.
+</para>
+
+<para>
+Now that the corresponding UNIX account has been created, the next step is to create
+the Samba account for the client containing the well-known initial
+Machine Trust Account password. This can be done using the
+<command>smbpasswd</command> command
+as shown here:
+</para>
+
+<para>
+<screen>
+&rootprompt;<userinput>smbpasswd -a -m <replaceable>machine_name</replaceable></userinput>
+</screen>
+</para>
+
+<para>
+where <replaceable>machine_name</replaceable> is the machine's NetBIOS
+name. The RID of the new machine account is generated from the UID of
+the corresponding UNIX account.
+</para>
+
+<warning>
+<title>Join the client to the domain immediately</title>
+
+<para>
+Manually creating a Machine Trust Account using this method is the
+equivalent of creating a Machine Trust Account on a Windows NT PDC using
+<indexterm><primary>Server Manager</primary></indexterm>
+the <application>Server Manager</application>. From the time at which the
+account is created to the time the client joins the domain and
+changes the password, your domain is vulnerable to an intruder joining
+your domain using a machine with the same NetBIOS name. A PDC inherently
+trusts members of the domain and will serve out a large degree of user
+information to such clients. You have been warned!
+</para>
+</warning>
+</sect2>
+
+<sect2>
+<title>Managing Domain Machine Accounts using NT4 Server Manager</title>
+
+<para>
+A working <smbconfoption><name>add machine script</name></smbconfoption> script is essential
+for machine trust accounts to be automatically created. This applies no matter whether
+one uses automatic account creation, or if one wishes to use the NT4 Domain Server Manager.
+</para>
+
+<para>
+<indexterm><primary>SRVTOOLS.EXE</primary></indexterm>
+If the machine from which you are trying to manage the domain is an
+<application>MS Windows NT4 workstation or MS Windows 200x/XP Professional</application>,
+the tool of choice is the package called <command>SRVTOOLS.EXE</command>.
+When executed in the target directory it will unpack <command>SrvMgr.exe</command>
+and <command>UsrMgr.exe</command> (both are domain management tools for MS Windows NT4 workstation).
+</para>
+
+<para>
+<indexterm><primary>Nexus.exe</primary></indexterm>
+If your workstation is a <application>Microsoft Windows 9x/Me</application> family product
+ you should download the <command>Nexus.exe</command> package from the Microsoft web site.
+When executed from the target directory this will unpack the same tools but for use on
+this platform.
+</para>
+
+<para>
+Further information about these tools may be obtained from the following locations:
+</para>
+
+<para>
+<simplelist>
+<member><ulink noescape="1" url="http://support.microsoft.com/default.aspx?scid=kb;en-us;173673"/></member>
+<member><ulink noescape="1" url="http://support.microsoft.com/default.aspx?scid=kb;en-us;172540"/></member>
+</simplelist>
+</para>
+
+<para>
+Launch the <command>srvmgr.exe</command> (Server Manager for Domains) and follow these steps:
+</para>
+
+<procedure>
+<title>Server Manager Account Machine Account Management</title>
+ <step><para>
+ From the menu select <guimenu>Computer</guimenu>.
+ </para></step>
+
+ <step><para>
+ Click <guimenuitem>Select Domain</guimenuitem>.
+ </para></step>
+
+ <step><para>
+ Click the name of the domain you wish to administer in the
+ <guilabel>Select Domain</guilabel> panel and then click
+ <guibutton>OK</guibutton>.
+ </para></step>
+
+ <step><para>
+ Again from the menu select <guimenu>Computer</guimenu>.
+ </para></step>
+
+ <step><para>
+ Select <guimenuitem>Add to Domain</guimenuitem>.
+ </para></step>
+
+ <step><para>
+ In the dialog box, click the radio button to
+ <guilabel>Add NT Workstation of Server</guilabel>, then
+ enter the machine name in the field provided, and click the
+ <guibutton>Add</guibutton> button.
+ </para></step>
+</procedure>
+
+</sect2>
+
+<sect2>
+<title>On-the-Fly Creation of Machine Trust Accounts</title>
+
+<para>
+The second (and recommended) way of creating Machine Trust Accounts is
+simply to allow the Samba server to create them as needed when the client
+is joined to the domain.
+</para>
+
+<para>Since each Samba Machine Trust Account requires a corresponding UNIX account, a method
+for automatically creating the UNIX account is usually supplied; this requires configuration of the
+add machine script option in &smb.conf;. This method is not required, however, corresponding UNIX
+accounts may also be created manually.
+</para>
+
+
+<para>
+Here is an example for a Red Hat Linux system.
+</para>
+
+<para><smbconfblock>
+<smbconfsection>[global]</smbconfsection>
+<smbconfcomment>&lt;...remainder of parameters...&gt;</smbconfcomment>
+<smbconfoption><name>add machine script</name><value>/usr/sbin/useradd -d /dev/null -g 100 \</value></smbconfoption>
+<member><parameter> -s /bin/false -M %u</parameter></member>
+</smbconfblock></para>
+
+
+</sect2>
+
+
+<sect2><title>Making an MS Windows Workstation or Server a Domain Member</title>
+
+<para>
+The procedure for making an MS Windows workstation or server a member of the domain varies
+with the version of Windows.
+</para>
+
+<sect3>
+ <title>Windows 200x/XP Professional Client</title>
+
+ <para>
+ When the user elects to make the client a Domain Member, Windows 200x prompts for
+ an account and password that has privileges to create machine accounts in the domain.
+ A Samba Administrator Account (i.e., a Samba account that has <constant>root</constant> privileges on the
+ Samba server) must be entered here; the operation will fail if an ordinary user
+ account is given.
+ </para>
+
+ <para>
+ For security reasons, the password for this Administrator Account should be set
+ to a password that is other than that used for the root user in <filename>/etc/passwd</filename>.
+ </para>
+
+ <para>
+ The name of the account that is used to create Domain Member machine accounts can be
+ anything the network administrator may choose. If it is other than <constant>root</constant>
+ then this is easily mapped to <constant>root</constant> in the file named in the &smb.conf; parameter
+ <smbconfoption><name>username map</name><value>/etc/samba/smbusers</value></smbconfoption>.
+ </para>
+
+ <para>
+ The session key of the Samba Administrator Account acts as an encryption key for setting the password of the machine trust
+ account. The Machine Trust Account will be created on-the-fly, or updated if it already exists.
+ </para>
+</sect3>
+
+<sect3>
+ <title>Windows NT4 Client</title>
+
+ <para>
+ If the Machine Trust Account was created manually, on the
+ Identification Changes menu enter the domain name, but do not
+ check the box <guilabel>Create a Computer Account in the Domain</guilabel>.
+ In this case, the existing Machine Trust Account is used to join the machine
+ to the domain.
+ </para>
+
+ <para>
+ If the Machine Trust Account is to be created on-the-fly, on the Identification Changes menu enter the domain
+ name and check the box <guilabel>Create a Computer Account in the Domain</guilabel>. In this case, joining
+ the domain proceeds as above for Windows 2000 (i.e., you must supply a Samba Administrator Account when
+ prompted).
+ </para>
+</sect3>
+
+<sect3>
+ <title>Samba Client</title>
+
+ <para>Joining a Samba client to a domain is documented in
+ <link linkend="domain-member-server">Domain Member Server</link>.
+ </para>
+</sect3>
+
+</sect2>
+</sect1>
+
+<sect1 id="domain-member-server">
+<title>Domain Member Server</title>
+
+<para>
+This mode of server operation involves the Samba machine being made a member
+of a domain security context. This means by definition that all user
+authentication will be done from a centrally defined authentication regime.
+The authentication regime may come from an NT3/4-style (old domain technology)
+server, or it may be provided from an Active Directory server (ADS) running on
+MS Windows 2000 or later.
+</para>
+
+<para>
+<emphasis>
+Of course it should be clear that the authentication backend itself could be
+from any distributed directory architecture server that is supported by Samba.
+This can be LDAP (from OpenLDAP), or Sun's iPlanet, or NetWare Directory
+Server, and so on.
+</emphasis>
+</para>
+
+<para><note>
+When Samba is configured to use an LDAP, or other identity management and/or
+directory service, it is Samba that continues to perform user and machine
+authentication. It should be noted that the LDAP server does not perform
+authentication handling in place of what Samba is designed to do.
+</note></para>
+
+<para>
+Please refer to <link linkend="samba-pdc">Domain Control</link>, for more information regarding
+how to create a domain machine account for a Domain Member server as well as for
+information on how to enable the Samba Domain Member machine to join the domain
+and be fully trusted by it.
+</para>
+
+<sect2>
+<title>Joining an NT4-type Domain with Samba-3</title>
+
+<para><link linkend="assumptions">Next table</link> lists names that have been used in the remainder of this chapter.</para>
+
+<table frame="all" id="assumptions"><title>Assumptions</title>
+ <tgroup cols="2">
+ <colspec align="right"/>
+ <colspec align="left"/>
+ <tbody>
+ <row>
+ <entry>NetBIOS name:</entry><entry>SERV1</entry>
+ </row>
+ <row>
+ <entry>Windows 200x/NT domain name:</entry><entry>&example.workgroup;</entry>
+ </row>
+ <row>
+ <entry>Domain's PDC NetBIOS name:</entry><entry>DOMPDC</entry>
+ </row>
+ <row>
+ <entry>Domain's BDC NetBIOS names:</entry><entry>DOMBDC1 and DOMBDC2</entry>
+ </row>
+ </tbody>
+ </tgroup>
+</table>
+
+<para>
+First, you must edit your &smb.conf; file to tell Samba it should now use domain security.
+</para>
+
+<para>
+ Change (or add) your
+ <smbconfoption><name>security</name></smbconfoption> line in the [global] section
+of your &smb.conf; to read:
+</para>
+
+<para>
+<smbconfblock>
+<smbconfoption><name>security</name><value>domain</value></smbconfoption>
+</smbconfblock>
+</para>
+
+<para>
+Next change the <smbconfoption><name>workgroup</name></smbconfoption> line in the <smbconfsection>[global]</smbconfsection>
+section to read:
+</para>
+
+<para>
+<smbconfblock>
+<smbconfoption><name>workgroup</name><value>&example.workgroup;</value></smbconfoption>
+</smbconfblock>
+</para>
+
+<para>
+This is the name of the domain we are joining.
+</para>
+
+<para>
+You must also have the parameter <smbconfoption><name>encrypt passwords</name></smbconfoption>
+set to <constant>yes</constant> in order for your users to authenticate to the NT PDC.
+This is the default setting if this parameter is not specified. There is no need to specify this
+parameter, but if it is specified in the &smb.conf; file, it must be set to <constant>Yes</constant>.
+</para>
+
+<para>
+Finally, add (or modify) a <smbconfoption><name>password server</name></smbconfoption> line in the [global]
+section to read:
+</para>
+
+<para>
+<smbconfblock>
+<smbconfoption><name>password server</name><value>DOMPDC DOMBDC1 DOMBDC2</value></smbconfoption>
+</smbconfblock>
+</para>
+
+<para>
+These are the primary and backup Domain Controllers Samba
+will attempt to contact in order to authenticate users. Samba will
+try to contact each of these servers in order, so you may want to
+rearrange this list in order to spread out the authentication load
+among Domain Controllers.
+</para>
+
+<para>
+Alternately, if you want smbd to automatically determine
+the list of Domain Controllers to use for authentication, you may
+set this line to be:
+</para>
+
+<para>
+<smbconfblock>
+<smbconfoption><name>password server</name><value>*</value></smbconfoption>
+</smbconfblock>
+</para>
+
+<para>
+This method allows Samba to use exactly the same mechanism that NT does. The
+method either uses broadcast-based name resolution, performs a WINS database
+lookup in order to find a Domain Controller against which to authenticate,
+or locates the Domain Controller using DNS name resolution.
+</para>
+
+<para>
+To join the domain, run this command:
+</para>
+
+<para>
+<screen>
+&rootprompt;<userinput>net join -S DOMPDC -U<replaceable>Administrator%password</replaceable></userinput>
+</screen>
+</para>
+
+<para>
+If the <option>-S DOMPDC</option> argument is not given, the domain name will be obtained from &smb.conf;.
+</para>
+
+<para>
+The machine is joining the domain DOM, and the PDC for that domain (the only machine
+that has write access to the domain SAM database) is DOMPDC, therefore use the <option>-S</option>
+option. The <replaceable>Administrator%password</replaceable> is the login name and
+password for an account that has the necessary privilege to add machines to the
+domain. If this is successful, you will see the message in your terminal window the
+text shown below. Where the older NT4 style domain architecture is used:
+<screen>
+<computeroutput>Joined domain DOM.</computeroutput>
+</screen>
+</para>
+
+<para>
+Where Active Directory is used:
+<screen>
+<computeroutput>Joined SERV1 to realm MYREALM.</computeroutput>
+</screen>
+</para>
+
+<para>
+Refer to the <command>net</command> man page for further information.
+</para>
+
+<para>
+This process joins the server to the domain without having to create the machine
+trust account on the PDC beforehand.
+</para>
+
+<para>
+This command goes through the machine account password change protocol, then writes
+the new (random) machine account password for this Samba server into a file in the
+same directory in which a smbpasswd file would be normally stored:
+<screen>
+<filename>/usr/local/samba/private/secrets.tdb</filename>
+or
+<filename>/etc/samba/secrets.tdb</filename>.
+</screen>
+</para>
+
+<para>
+This file is created and owned by root and is not readable by any other user. It is
+the key to the Domain-level security for your system, and should be treated as carefully
+as a shadow password file.
+</para>
+
+<para>
+Finally, restart your Samba daemons and get ready for clients to begin using domain
+security. The way you can restart your Samba daemons depends on your distribution,
+but in most cases the following will suffice:
+<screen>
+&rootprompt;/etc/init.d/samba restart
+</screen>
+</para>
+
+</sect2>
+
+<sect2>
+<title>Why Is This Better Than <parameter>security = server</parameter>?</title>
+
+<para>
+Currently, domain security in Samba does not free you from
+having to create local UNIX users to represent the users attaching
+to your server. This means that if Domain user <constant>DOM\fred
+</constant> attaches to your Domain Security Samba server, there needs
+to be a local UNIX user fred to represent that user in the UNIX
+file system. This is similar to the older Samba security mode
+<smbconfoption><name>security</name><value>server</value></smbconfoption>,
+where Samba would pass through the authentication request to a Windows
+NT server in the same way as a Windows 95 or Windows 98 server would.
+</para>
+
+<para>
+Please refer to <link linkend="winbind">Winbind: Use of Domain Accounts</link> chapter, for information on a system
+to automatically assign UNIX UIDs and GIDs to Windows NT Domain users and groups.
+</para>
+
+<para>
+The advantage to Domain-level security is that the
+authentication in Domain-level security is passed down the authenticated
+RPC channel in exactly the same way that an NT server would do it. This
+means Samba servers now participate in domain trust relationships in
+exactly the same way NT servers do (i.e., you can add Samba servers into
+a resource domain and have the authentication passed on from a resource
+domain PDC to an account domain PDC).
+</para>
+
+<para>
+In addition, with <smbconfoption><name>security</name><value>server</value></smbconfoption>, every Samba
+daemon on a server has to keep a connection open to the
+authenticating server for as long as that daemon lasts. This can drain
+the connection resources on a Microsoft NT server and cause it to run
+out of available connections. With <smbconfoption><name>security</name><value>domain</value></smbconfoption>,
+however, the Samba daemons connect to the PDC/BDC only for as long
+as is necessary to authenticate the user and then drop the connection,
+thus conserving PDC connection resources.
+</para>
+
+<para>
+And finally, acting in the same manner as an NT server
+authenticating to a PDC means that as part of the authentication
+reply, the Samba server gets the user identification information such
+as the user SID, the list of NT groups the user belongs to, and so on.
+</para>
+
+<note>
+<para>
+Much of the text of this document was first published in the Web magazine
+<ulink url="http://www.linuxworld.com">LinuxWorld</ulink> as the article <ulink
+url="http://www.linuxworld.com/linuxworld/lw-1998-10/lw-10-samba.html"/>
+<emphasis>Doing the NIS/NT Samba</emphasis>.
+</para>
+</note>
+
+</sect2>
+</sect1>
+
+<sect1 id="ads-member">
+<title>Samba ADS Domain Membership</title>
+
+<para>
+<indexterm significance="preferred"><primary>Active Directory</primary></indexterm>
+<indexterm significance="preferred"><primary>ADS</primary><see>Active Directory</see></indexterm>
+<indexterm><primary>KDC</primary></indexterm>
+<indexterm><primary>Kerberos</primary></indexterm>
+This is a rough guide to setting up Samba-3 with Kerberos authentication against a
+Windows 200x KDC. A familiarity with Kerberos is assumed.
+</para>
+
+<sect2>
+<title>Configure &smb.conf;</title>
+
+<para>
+You must use at least the following three options in &smb.conf;:
+</para>
+
+<para><smbconfblock>
+<smbconfoption><name>realm</name><value>your.kerberos.REALM</value></smbconfoption>
+<smbconfoption><name>security</name><value>ADS</value></smbconfoption>
+<smbconfcomment>The following parameter need only be specified if present.</smbconfcomment>
+<smbconfcomment>The default setting is not present is Yes.</smbconfcomment>
+<smbconfoption><name>encrypt passwords</name><value>yes</value></smbconfoption>
+</smbconfblock></para>
+
+<para>
+In case samba cannot correctly identify the appropriate ADS server using the realm name, use the
+<smbconfoption><name>password server</name></smbconfoption> option in &smb.conf;:
+<smbconfblock>
+<smbconfoption><name>password server</name><value>your.kerberos.server</value></smbconfoption>
+</smbconfblock>
+</para>
+
+<note><para>
+You do <emphasis>not</emphasis> need a smbpasswd file, and older clients will be authenticated as
+if <smbconfoption><name>security</name><value>domain</value></smbconfoption>, although it will not do any harm and
+allows you to have local users not in the domain.
+</para></note>
+
+</sect2>
+
+<sect2>
+<title>Configure <filename>/etc/krb5.conf</filename></title>
+
+<para>
+<indexterm><primary>/etc/krb5.conf</primary></indexterm>
+<indexterm><primary>Kerberos</primary><secondary>/etc/krb5.conf</secondary></indexterm>
+With both MIT and Heimdal Kerberos, it is unnecessary to configure the
+<filename>/etc/krb5.conf</filename>, and it may be detrimental.
+</para>
+
+<para>
+Microsoft Active Directory servers automatically create SRV records in the DNS zone
+<parameter>_kerberos.REALM.NAME</parameter> for each KDC in the realm. This is part
+of the installation and configuration process used to create an Active Directory Domain.
+</para>
+
+<para>
+MIT's, as well as Heimdal's, recent KRB5 libraries default to checking for SRV records, so they will
+automatically find the KDCs. In addition, <filename>krb5.conf</filename> only allows specifying
+a single KDC, even there if there may be more than one. Using the DNS lookup allows the KRB5
+libraries to use whichever KDCs are available.
+</para>
+
+<para>
+When manually configuring <filename>krb5.conf</filename>, the minimal configuration is:
+</para>
+
+<para>
+ <smbfile name="krb5.conf">
+ <programlisting>
+[libdefaults]
+ default_realm = YOUR.KERBEROS.REALM
+
+[realms]
+ YOUR.KERBEROS.REALM = {
+ kdc = your.kerberos.server
+ }
+
+[domain_realms]
+ .kerberos.server = YOUR.KERBEROS.REALM
+</programlisting></smbfile></para>
+
+<para>
+When using Heimdal versions before 0.6 use the following configuration settings:
+<screen>
+[libdefaults]
+ default_realm = YOUR.KERBEROS.REALM
+ default_etypes = des-cbc-crc des-cbc-md5
+ default_etypes_des = des-cbc-crc des-cbc-md5
+
+[realms]
+ YOUR.KERBEROS.REALM = {
+ kdc = your.kerberos.server
+ }
+
+[domain_realms]
+ .kerberos.server = YOUR.KERBEROS.REALM
+</screen>
+</para>
+
+<para>
+<indexterm><primary>kinit</primary></indexterm>
+Test your config by doing a <userinput>kinit
+<replaceable>USERNAME</replaceable>@<replaceable>REALM</replaceable></userinput> and
+making sure that your password is accepted by the Win2000 KDC.
+</para>
+
+<para>
+With Heimdal versions earlier than 0.6.x you only can use newly created accounts
+in ADS or accounts that have had the password changed once after migration, or
+in case of <constant>Administrator</constant> after installation. At the
+moment, a Windows 2003 KDC can only be used with a Heimdal releases later than 0.6
+(and no default etypes in krb5.conf). Unfortunately this whole area is still
+in a state of flux.
+</para>
+
+<note><para>
+The realm must be in uppercase or you will get <quote><errorname>Cannot find KDC for
+requested realm while getting initial credentials</errorname></quote> error (Kerberos
+is case-sensitive!).
+</para></note>
+
+<note><para>
+Time between the two servers must be synchronized. You will get a
+<quote><errorname>kinit(v5): Clock skew too great while getting initial credentials</errorname></quote>
+if the time difference is more than five minutes.
+</para></note>
+
+<para>
+Clock skew limits are configurable in the Kerberos protocols. The default setting is
+five minutes.
+</para>
+
+<para>
+You also must ensure that you can do a reverse DNS lookup on the IP
+address of your KDC. Also, the name that this reverse lookup maps to
+must either be the NetBIOS name of the KDC (i.e., the hostname with no
+domain attached) or it can alternately be the NetBIOS name followed by the realm.
+</para>
+
+<para>
+The easiest way to ensure you get this right is to add a
+<filename>/etc/hosts</filename> entry mapping the IP address of your KDC to
+its NetBIOS name. If you do not get this correct then you will get a
+<errorname>local error</errorname> when you try to join the realm.
+</para>
+
+<para>
+If all you want is Kerberos support in &smbclient; then you can skip
+directly to <link linkend="ads-test-smbclient">Testing with &smbclient;</link> now.
+<link linkend="ads-create-machine-account">Create the Computer Account</link> and
+<link linkend="ads-test-server">Testing Server Setup</link>
+are needed only if you want Kerberos support for &smbd; and &winbindd;.
+</para>
+
+</sect2>
+
+<sect2 id="ads-create-machine-account">
+<title>Create the Computer Account</title>
+
+<para>
+As a user who has write permission on the Samba private directory (usually root), run:
+<screen>
+&rootprompt; <userinput>net ads join -U Administrator%password</userinput>
+</screen>
+</para>
+
+<para>
+When making a Windows client a member of an ADS domain within a complex organization, you
+may want to create the machine account within a particular organizational unit. Samba-3 permits
+this to be done using the following syntax:
+<screen>
+&rootprompt; <userinput>kinit Administrator@your.kerberos.REALM</userinput>
+&rootprompt; <userinput>net ads join <quote>organizational_unit</quote></userinput>
+</screen>
+</para>
+
+<para>
+For example, you may want to create the machine account in a container called <quote>Servers</quote>
+under the organizational directory <quote>Computers\BusinessUnit\Department</quote> like this:
+<screen>
+&rootprompt; <userinput>net ads join "Computers\BusinessUnit\Department\Servers"</userinput>
+</screen>
+</para>
+
+<?latex \newpage ?>
+
+<sect3>
+<title>Possible Errors</title>
+
+<para>
+<variablelist>
+ <varlistentry><term><errorname>ADS support not compiled in</errorname></term>
+ <listitem><para>Samba must be reconfigured (remove config.cache) and recompiled
+ (make clean all install) after the Kerberos libraries and headers files are installed.
+ </para></listitem></varlistentry>
+
+ <varlistentry><term><errorname>net ads join prompts for user name</errorname></term>
+ <listitem><para>You need to login to the domain using <userinput>kinit
+ <replaceable>USERNAME</replaceable>@<replaceable>REALM</replaceable></userinput>.
+ <replaceable>USERNAME</replaceable> must be a user who has rights to add a machine
+ to the domain. </para></listitem></varlistentry>
+
+ <varlistentry><term>Unsupported encryption/or checksum types</term>
+ <listitem><para>
+ Make sure that the <filename>/etc/krb5.conf</filename> is correctly configured
+ for the type and version of Kerberos installed on the system.
+ </para></listitem></varlistentry>
+</variablelist>
+</para>
+
+</sect3>
+
+</sect2>
+
+<sect2 id="ads-test-server">
+<title>Testing Server Setup</title>
+
+<para>
+If the join was successful, you will see a new computer account with the
+NetBIOS name of your Samba server in Active Directory (in the <quote>Computers</quote>
+folder under Users and Computers.
+</para>
+
+<para>
+On a Windows 2000 client, try <userinput>net use * \\server\share</userinput>. You should
+be logged in with Kerberos without needing to know a password. If this fails then run
+<userinput>klist tickets</userinput>. Did you get a ticket for the server? Does it have
+an encryption type of DES-CBC-MD5?
+</para>
+
+<para><note>
+Samba can use both DES-CBC-MD5 encryption as well as ARCFOUR-HMAC-MD5 encoding.
+</note></para>
+
+</sect2>
+
+<sect2 id="ads-test-smbclient">
+<title>Testing with &smbclient;</title>
+
+
+<para>
+<indexterm><primary>smbclient</primary></indexterm>
+On your Samba server try to login to a Win2000 server or your Samba
+server using &smbclient; and Kerberos. Use &smbclient; as usual, but
+specify the <option>-k</option> option to choose Kerberos authentication.
+</para>
+
+</sect2>
+
+<sect2>
+<title>Notes</title>
+
+<para>
+You must change administrator password at least once after DC
+install, to create the right encryption types.
+</para>
+
+<para>
+Windows 200x does not seem to create the <parameter>_kerberos._udp</parameter> and <parameter>_ldap._tcp</parameter> in
+the default DNS setup. Perhaps this will be fixed later in service packs.
+</para>
+
+</sect2>
+</sect1>
+
+<sect1>
+<title>Sharing User ID Mappings between Samba Domain Members</title>
+
+<para>
+Samba maps UNIX users and groups (identified by UIDs and GIDs) to Windows users and groups (identified by SIDs).
+These mappings are done by the <parameter>idmap</parameter> subsystem of Samba.
+</para>
+
+<para>
+In some cases it is useful to share these mappings between Samba Domain Members,
+so <emphasis>name->id</emphasis> mapping is identical on all machines.
+This may be needed in particular when sharing files over both CIFS and NFS.
+</para>
+
+<para>To use the <emphasis>LDAP</emphasis> <parameter>ldap idmap suffix</parameter>, set:</para>
+
+<smbconfblock>
+<smbconfoption><name>ldap idmap suffix</name><value>ou=Idmap,dc=quenya,dc=org</value></smbconfoption>
+</smbconfblock>
+
+<para>See the &smb.conf; man page entry for the <smbconfoption><name>ldap idmap suffix</name><value></value></smbconfoption>
+parameter for further information.</para>
+
+<para>
+Do not forget to specify also the <smbconfoption><name>ldap admin dn</name></smbconfoption>
+and to make certain to set the LDAP administrative password into the <filename>secrets.tdb</filename> using:
+<screen>
+&rootprompt; smbpasswd -w ldap-admin-password
+</screen></para>
+
+</sect1>
+
+<sect1>
+<title>Common Errors</title>
+
+<para>
+In the process of adding/deleting/re-adding Domain Member machine accounts, there are
+many traps for the unwary player and many <quote>little</quote> things that can go wrong.
+It is particularly interesting how often subscribers on the Samba mailing list have concluded
+after repeated failed attempts to add a machine account that it is necessary to <quote>re-install</quote>
+MS Windows on the machine. In truth, it is seldom necessary to reinstall because of this type
+of problem. The real solution is often quite simple and with an understanding of how MS Windows
+networking functions, it is easy to overcome.
+</para>
+
+<sect2>
+<title>Cannot Add Machine Back to Domain</title>
+
+<para>
+<quote>A Windows workstation was re-installed. The original domain machine
+account was deleted and added immediately. The workstation will not join the domain if I use
+the same machine name. Attempts to add the machine fail with a message that the machine already
+exists on the network &smbmdash; I know it does not. Why is this failing?</quote>
+</para>
+
+<para>
+The original name is still in the NetBIOS name cache and must expire after machine account
+deletion before adding that same name as a Domain Member again. The best advice is to delete
+the old account and then add the machine with a new name.
+</para>
+
+</sect2>
+
+<sect2>
+<title>Adding Machine to Domain Fails</title>
+
+<para>
+<quote>Adding a Windows 200x or XP Professional machine to the Samba PDC Domain fails with a
+message that, <errorname>`The machine could not be added at this time, there is a network problem.
+Please try again later.'</errorname> Why?</quote>
+</para>
+
+<para>
+You should check that there is an <smbconfoption><name>add machine script</name></smbconfoption> in your &smb.conf;
+file. If there is not, please add one that is appropriate for your OS platform. If a script
+has been defined, you will need to debug its operation. Increase the <smbconfoption><name>log level</name><value></value></smbconfoption>
+in the &smb.conf; file to level 10, then try to rejoin the domain. Check the logs to see which
+operation is failing.
+</para>
+
+<para>
+Possible causes include:
+</para>
+
+<itemizedlist>
+ <listitem><para>
+ The script does not actually exist, or could not be located in the path specified.
+ </para>
+
+ <para>
+ <emphasis>Corrective action:</emphasis> Fix it. Make sure when run manually
+ that the script will add both the UNIX system account and the Samba SAM account.
+ </para></listitem>
+
+ <listitem><para>
+ The machine could not be added to the UNIX system accounts file <filename>/etc/passwd</filename>.
+ </para>
+
+ <para>
+ <emphasis>Corrective action:</emphasis> Check that the machine name is a legal UNIX
+ system account name. If the UNIX utility <command>useradd</command> is called,
+ then make sure that the machine name you are trying to add can be added using this
+ tool. <command>Useradd</command> on some systems will not allow any upper case characters
+ nor will it allow spaces in the name.
+ </para></listitem>
+</itemizedlist>
+
+<para>
+The <smbconfoption><name>add machine script</name></smbconfoption> does not create the
+machine account in the Samba backend database, it is there only to create a UNIX system
+account to which the Samba backend database account can be mapped.
+</para>
+
+</sect2>
+
+<sect2>
+ <title>I Can't Join a Windows 2003 PDC</title>
+
+ <para>Windows 2003 requires SMB signing. Client side SMB signing has been implemented in Samba-3.0.
+ Set <smbconfoption><name>client use spnego</name><value>yes</value></smbconfoption> when communicating
+ with a Windows 2003 server.</para>
+</sect2>
+
+</sect1>
+</chapter>