docs/htmldocs/samba-pdc.html

   1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
   2 <html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Chapter 5.
   3 Samba as an NT4 or Win2k Primary Domain Controller
   4 </title><link rel="stylesheet" href="samba.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.59.1"><link rel="home" href="index.html" title="SAMBA Project Documentation"><link rel="up" href="type.html" title="Part II. Server Configuration Basics"><link rel="previous" href="securitylevels.html" title="Chapter 4. Samba as Stand-Alone Server"><link rel="next" href="samba-bdc.html" title="Chapter 6.
   5 Samba Backup Domain Controller to Samba Domain Control
   6 "></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 5.
   7 Samba as an NT4 or Win2k Primary Domain Controller
   8 </th></tr><tr><td width="20%" align="left"><a accesskey="p" href="securitylevels.html">Prev</a> </td><th width="60%" align="center">Part II. Server Configuration Basics</th><td width="20%" align="right"> <a accesskey="n" href="samba-bdc.html">Next</a></td></tr></table><hr></div><div class="chapter" lang="en"><div class="titlepage"><div><h2 class="title"><a name="samba-pdc"></a>Chapter 5.
   9 Samba as an NT4 or Win2k Primary Domain Controller
  10 </h2></div><div><div class="author"><h3 class="author">Gerald (Jerry) Carter</h3><div class="affiliation"><span class="orgname">Samba Team<br></span><div class="address"><p><tt>&lt;<a href="mailto:jerry@samba.org">jerry@samba.org</a>&gt;</tt></p></div></div></div></div><div><div class="author"><h3 class="author">John H. Terpstra</h3><div class="affiliation"><span class="orgname">Samba Team<br></span><div class="address"><p><tt>&lt;<a href="mailto:jht@samba.org">jht@samba.org</a>&gt;</tt></p></div></div></div></div><div><div class="author"><h3 class="author">David Bannon</h3><div class="affiliation"><span class="orgname">Samba Team<br></span><div class="address"><p><tt>&lt;<a href="mailto:dbannon@samba.org">dbannon@samba.org</a>&gt;</tt></p></div></div></div></div><div><p class="pubdate"> (26 Apr 2001) </p></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><a href="samba-pdc.html#id2807495">Prerequisite Reading</a></dt><dt><a href="samba-pdc.html#id2807518">
  11 Background
  12 </a></dt><dt><a href="samba-pdc.html#id2877458">Configuring the Samba Domain Controller</a></dt><dt><a href="samba-pdc.html#id2877759">Creating Machine Trust Accounts and Joining Clients to the Domain</a></dt><dd><dl><dt><a href="samba-pdc.html#id2878028">Manual Creation of Machine Trust Accounts</a></dt><dt><a href="samba-pdc.html#id2878262">&quot;On-the-Fly&quot; Creation of Machine Trust Accounts</a></dt><dt><a href="samba-pdc.html#id2878318">Joining the Client to the Domain</a></dt></dl></dd><dt><a href="samba-pdc.html#id2878425">Common Problems and Errors</a></dt><dd><dl><dt><a href="samba-pdc.html#id2878432">I cannot include a '$' in a machine name</a></dt><dt><a href="samba-pdc.html#id2878470">I get told &quot;You already have a connection to the Domain....&quot;
  13 or &quot;Cannot join domain, the credentials supplied conflict with an
  14 existing set..&quot; when creating a machine trust account.</a></dt><dt><a href="samba-pdc.html#id2878517">The system can not log you on (C000019B)....</a></dt><dt><a href="samba-pdc.html#id2878568">The machine trust account for this computer either does not
  15 exist or is not accessible.</a></dt><dt><a href="samba-pdc.html#id2878617">When I attempt to login to a Samba Domain from a NT4/W2K workstation,
  16 I get a message about my account being disabled.</a></dt></dl></dd><dt><a href="samba-pdc.html#id2878642">Domain Control for Windows 9x/ME</a></dt><dd><dl><dt><a href="samba-pdc.html#id2878805">Configuration Instructions:   Network Logons</a></dt></dl></dd></dl></div><div class="sect1" lang="en"><div class="titlepage"><div><h2 class="title" style="clear: both"><a name="id2807495"></a>Prerequisite Reading</h2></div></div><p>
  17 Before you continue reading in this chapter, please make sure
  18 that you are comfortable with configuring basic files services
  19 in smb.conf and how to enable and administer password
  20 encryption in Samba.  Theses two topics are covered in the
  21 <tt>smb.conf</tt> manpage.
  22 </p></div><div class="sect1" lang="en"><div class="titlepage"><div><h2 class="title" style="clear: both"><a name="id2807518"></a>
  23 Background
  24 </h2></div></div><p>
  25 This article outlines the steps necessary for configuring Samba as a PDC.
  26 It is necessary to have a working Samba server prior to implementing the
  27 PDC functionality.
  28 </p><div class="itemizedlist"><ul type="disc"><li><p>
  29         Domain logons for Windows NT 4.0 / 200x / XP Professional clients.
  30         </p></li><li><p>
  31         Placing Windows 9x / Me clients in user level security
  32         </p></li><li><p>
  33         Retrieving a list of users and groups from a Samba PDC to
  34         Windows 9x / Me / NT / 200x / XP Professional clients
  35         </p></li><li><p>
  36         Roaming Profiles
  37         </p></li><li><p>
  38         Network/System Policies
  39         </p></li></ul></div><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
  40 Roaming Profiles and System/Network policies are advanced network administration topics
  41 that are covered separately in this document.
  42 </p></div><p>
  43 The following functionalities are new to the Samba 3.0 release:
  44 </p><div class="itemizedlist"><ul type="disc"><li><p>
  45         Windows NT 4 domain trusts
  46         </p></li><li><p>
  47         Adding users via the User Manager for Domains
  48         </p></li></ul></div><p>
  49 The following functionalities are NOT provided by Samba 3.0:
  50 </p><div class="itemizedlist"><ul type="disc"><li><p>
  51         SAM replication with Windows NT 4.0 Domain Controllers
  52         (i.e. a Samba PDC and a Windows NT BDC or vice versa)
  53         </p></li><li><p>
  54         Acting as a Windows 2000 Domain Controller (i.e. Kerberos and
  55         Active Directory)
  56         </p></li></ul></div><p>
  57 Please note that Windows 9x / Me / XP Home clients are not true members of a domain
  58 for reasons outlined in this article.  Therefore the protocol for
  59 support of Windows 9x-style domain logons is completely different
  60 from NT4 / Win2k type domain logons and has been officially supported for some
  61 time.
  62 </p><p><span class="emphasis"><em>
  63 MS Windows XP Home edition is NOT able to join a domain and does not permit
  64 the use of domain logons.</em></span>
  65 </p><p>
  66 Implementing a Samba PDC can basically be divided into 3 broad
  67 steps.
  68 </p><div class="orderedlist"><ol type="1"><li><p>
  69         Configuring the Samba PDC
  70         </p></li><li><p>
  71         Creating machine trust accounts and joining clients to the domain
  72         </p></li><li><p>
  73         Adding and managing domain user accounts
  74         </p></li></ol></div><p>
  75 There are other minor details such as user profiles, system
  76 policies, etc...  However, these are not necessarily specific
  77 to a Samba PDC as much as they are related to Windows NT networking
  78 concepts.
  79 </p></div><div class="sect1" lang="en"><div class="titlepage"><div><h2 class="title" style="clear: both"><a name="id2877458"></a>Configuring the Samba Domain Controller</h2></div></div><p>
  80 The first step in creating a working Samba PDC is to
  81 understand the parameters necessary in smb.conf. Here we
  82 attempt to explain the parameters that are covered in
  83 the <tt>smb.conf</tt> man page.
  84 </p><p>
  85 Here is an example <tt>smb.conf</tt> for acting as a PDC:
  86 </p><pre class="programlisting">
  87 [global]
  88     ; Basic server settings
  89     <a href="smb.conf.5.html#NETBIOSNAME" target="_top">netbios name</a> = <i><tt>POGO</tt></i>
  90     <a href="smb.conf.5.html#WORKGROUP" target="_top">workgroup</a> = <i><tt>NARNIA</tt></i>
  91
  92     ; User and Machine Account Backends
  93     ; Choices are: tdbsam, tdbsam_nua, smbpasswd, smbpasswd_nua, ldapsam, ldapsam_nua, ...
  94     ;              mysqlsam, xmlsam, guest
  95     <a href="smb.conf.5.html#PASSDBBACKEND" target="_top">passdb backend</a> = ldapsam, guest
  96
  97     ; we should act as the domain and local master browser
  98     <a href="smb.conf.5.html#OSLEVEL" target="_top">os level</a> = 64
  99     <a href="smb.conf.5.html#PERFERREDMASTER" target="_top">preferred master</a> = yes
 100     <a href="smb.conf.5.html#DOMAINMASTER" target="_top">domain master</a> = yes
 101     <a href="smb.conf.5.html#LOCALMASTER" target="_top">local master</a> = yes
 102
 103     ; security settings (must user security = user)
 104     <a href="smb.conf.5.html#SECURITYEQUALSUSER" target="_top">security</a> = user
 105
 106     ; encrypted passwords are a requirement for a PDC
 107     <a href="smb.conf.5.html#ENCRYPTPASSWORDS" target="_top">encrypt passwords</a> = yes
 108
 109     ; support domain logons
 110     <a href="smb.conf.5.html#DOMAINLOGONS" target="_top">domain logons</a> = yes
 111
 112     ; where to store user profiles?
 113     <a href="smb.conf.5.html#LOGONPATH" target="_top">logon path</a> = \\%N\profiles\%u
 114
 115     ; where is a user's home directory and where should it be mounted at?
 116     <a href="smb.conf.5.html#LOGONDRIVE" target="_top">logon drive</a> = H:
 117     <a href="smb.conf.5.html#LOGONHOME" target="_top">logon home</a> = \\homeserver\%u
 118
 119     ; specify a generic logon script for all users
 120     ; this is a relative **DOS** path to the [netlogon] share
 121     <a href="smb.conf.5.html#LOGONSCRIPT" target="_top">logon script</a> = logon.cmd
 122
 123 ; necessary share for domain controller
 124 [netlogon]
 125     <a href="smb.conf.5.html#PATH" target="_top">path</a> = /usr/local/samba/lib/netlogon
 126     <a href="smb.conf.5.html#READONLY" target="_top">read only</a> = yes
 127     <a href="smb.conf.5.html#WRITELIST" target="_top">write list</a> = <i><tt>ntadmin</tt></i>
 128
 129 ; share for storing user profiles
 130 [profiles]
 131     <a href="smb.conf.5.html#PATH" target="_top">path</a> = /export/smb/ntprofile
 132     <a href="smb.conf.5.html#READONLY" target="_top">read only</a> = no
 133     <a href="smb.conf.5.html#CREATEMASK" target="_top">create mask</a> = 0600
 134     <a href="smb.conf.5.html#DIRECTORYMASK" target="_top">directory mask</a> = 0700
 135 </pre><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
 136 The above parameters make for a full set of parameters that may define the server's mode
 137 of operation. The following parameters are the essentials alone:
 138
 139 </p><pre class="programlisting">
 140         workgroup = NARNIA
 141         domain logons = Yes
 142         security = User
 143 </pre><p>
 144
 145 The additional parameters shown in the longer listing above just makes for a
 146 more complete environment.
 147 </p></div><p>
 148 There are a couple of points to emphasize in the above configuration.
 149 </p><div class="itemizedlist"><ul type="disc"><li><p>
 150         Encrypted passwords must be enabled.  For more details on how
 151         to do this, refer to <a href="passdb.html" title="Chapter 10. User information database">the User Database chapter</a>.
 152         </p></li><li><p>
 153         The server must support domain logons and a
 154         <tt>[netlogon]</tt> share
 155         </p></li><li><p>
 156         The server must be the domain master browser in order for Windows
 157         client to locate the server as a DC.  Please refer to the various
 158         Network Browsing documentation included with this distribution for
 159         details.
 160         </p></li></ul></div><p>
 161 Samba 3.0 offers a complete implementation of group mapping
 162 between Windows NT groups and Unix groups (this is really quite
 163 complicated to explain in a short space).
 164 </p></div><div class="sect1" lang="en"><div class="titlepage"><div><h2 class="title" style="clear: both"><a name="id2877759"></a>Creating Machine Trust Accounts and Joining Clients to the Domain</h2></div></div><p>
 165 A machine trust account is a Samba account that is used to
 166 authenticate a client machine (rather than a user) to the Samba
 167 server.  In Windows terminology, this is known as a &quot;Computer
 168 Account.&quot;</p><p>
 169 The password of a machine trust account acts as the shared secret for
 170 secure communication with the Domain Controller.  This is a security
 171 feature to prevent an unauthorized machine with the same NetBIOS name
 172 from joining the domain and gaining access to domain user/group
 173 accounts.  Windows NT, 200x, XP Professional clients use machine trust
 174 accounts, but Windows 9x / Me / XP Home clients do not.  Hence, a
 175 Windows 9x / Me / XP Home  client is never a true member of a domain
 176 because it does not possess a machine trust account, and thus has no
 177 shared secret with the domain controller.
 178 </p><p>A Windows PDC stores each machine trust account in the Windows
 179 Registry. A Samba-3 PDC also has to store machine trust account information
 180 in a suitable backend data store. With Samba-3 there can be multiple back-ends
 181 for this including:
 182 </p><div class="itemizedlist"><ul type="disc"><li><p>
 183         <span class="emphasis"><em>smbpasswd</em></span> - the plain ascii file stored used by
 184         earlier versions of Samba. This file configuration option requires
 185         a Unix/Linux system account for EVERY entry (ie: both for user and for
 186         machine accounts). This file will be located in the <span class="emphasis"><em>private</em></span>
 187         directory (default is /usr/local/samba/lib/private or on linux /etc/samba).
 188         </p></li><li><p>
 189         <span class="emphasis"><em>smbpasswd_nua</em></span> - This file is independant of the
 190         system wide user accounts. The use of this back-end option requires
 191         specification of the &quot;non unix account range&quot; option also. It is called
 192         smbpasswd and will be located in the <tt>private</tt> directory.
 193         </p></li><li><p>
 194         <span class="emphasis"><em>tdbsam</em></span> - a binary database backend that will be
 195         stored in the <span class="emphasis"><em>private</em></span> directory in a file called
 196         <span class="emphasis"><em>passwd.tdb</em></span>. The key benefit of this binary format
 197         file is that it can store binary objects that can not be accomodated
 198         in the traditional plain text smbpasswd file.
 199         </p></li><li><p>
 200         <span class="emphasis"><em>tdbsam_nua</em></span> like the smbpasswd_nua option above, this
 201         file allows the creation of arbitrary user and machine accounts without
 202         requiring that account to be added to the system (/etc/passwd) file. It
 203         too requires the specification of the &quot;non unix account range&quot; option
 204         in the [globals] section of the <tt>smb.conf</tt> file.
 205         </p></li><li><p>
 206         <span class="emphasis"><em>ldapsam</em></span> - An LDAP based back-end. Permits the
 207         LDAP server to be specified. eg: ldap://localhost or ldap://frodo.murphy.com
 208         </p></li><li><p>
 209         <span class="emphasis"><em>ldapsam_nua</em></span> - LDAP based back-end with no unix
 210         account requirement, like smbpasswd_nua and tdbsam_nua above.
 211         </p></li></ul></div><p>Read the chapter about the <a href="passdb.html" title="Chapter 10. User information database">User Database</a>
 212 for details.</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
 213 The new tdbsam and ldapsam account backends store vastly more information than
 214 smbpasswd is capable of. The new backend database includes capacity to specify
 215 per user settings for many parameters, over-riding global settings given in the
 216 <tt>smb.conf</tt> file. eg: logon drive, logon home, logon path, etc.
 217 </p></div><p>
 218 A Samba PDC, however, stores each machine trust account in two parts,
 219 as follows:
 220
 221 </p><div class="itemizedlist"><ul type="disc"><li><p>A Samba account, stored in the same location as user
 222     LanMan and NT password hashes (currently
 223     <tt>smbpasswd</tt>). The Samba account
 224     possesses and uses only the NT password hash.</p></li><li><p>A corresponding Unix account, typically stored in
 225     <tt>/etc/passwd</tt>. (Future releases will alleviate the need to
 226     create <tt>/etc/passwd</tt> entries.) </p></li></ul></div><p>
 227 </p><p>
 228 There are two ways to create machine trust accounts:
 229 </p><div class="itemizedlist"><ul type="disc"><li><p> Manual creation. Both the Samba and corresponding
 230         Unix account are created by hand.</p></li><li><p> &quot;On-the-fly&quot; creation. The Samba machine trust
 231         account is automatically created by Samba at the time the client
 232         is joined to the domain. (For security, this is the
 233         recommended method.) The corresponding Unix account may be
 234         created automatically or manually. </p></li></ul></div><div class="sect2" lang="en"><div class="titlepage"><div><h3 class="title"><a name="id2878028"></a>Manual Creation of Machine Trust Accounts</h3></div></div><p>
 235 The first step in manually creating a machine trust account is to
 236 manually create the corresponding Unix account in
 237 <tt>/etc/passwd</tt>.  This can be done using
 238 <b>vipw</b> or other 'add user' command that is normally
 239 used to create new Unix accounts.  The following is an example for a
 240 Linux based Samba server:
 241 </p><p>
 242   <tt>root# </tt><b>/usr/sbin/useradd -g 100 -d /dev/null -c <i><tt>&quot;machine
 243 nickname&quot;</tt></i> -s /bin/false <i><tt>machine_name</tt></i>$ </b>
 244 </p><p>
 245 <tt>root# </tt><b>passwd -l <i><tt>machine_name</tt></i>$</b>
 246 </p><p>On *BSD systems, this can be done using the 'chpass' utility:</p><p>
 247 <tt>root# </tt><b>chpass -a &quot;<i><tt>machine_name</tt></i>$:*:101:100::0:0:Workstation <i><tt>machine_name</tt></i>:/dev/null:/sbin/nologin&quot;</b>
 248 </p><p>
 249 The <tt>/etc/passwd</tt> entry will list the machine name
 250 with a &quot;$&quot; appended, won't have a password, will have a null shell and no
 251 home directory. For example a machine named 'doppy' would have an
 252 <tt>/etc/passwd</tt> entry like this:
 253 </p><pre class="programlisting">
 254 doppy$:x:505:501:<i><tt>machine_nickname</tt></i>:/dev/null:/bin/false
 255 </pre><p>
 256 Above, <i><tt>machine_nickname</tt></i> can be any
 257 descriptive name for the client, i.e., BasementComputer.
 258 <i><tt>machine_name</tt></i> absolutely must be the NetBIOS
 259 name of the client to be joined to the domain.  The &quot;$&quot; must be
 260 appended to the NetBIOS name of the client or Samba will not recognize
 261 this as a machine trust account.
 262 </p><p>
 263 Now that the corresponding Unix account has been created, the next step is to create
 264 the Samba account for the client containing the well-known initial
 265 machine trust account password.  This can be done using the <a href="smbpasswd.8.html" target="_top"><b>smbpasswd(8)</b></a> command
 266 as shown here:
 267 </p><p>
 268 <tt>root# </tt><b><tt>smbpasswd -a -m <i><tt>machine_name</tt></i></tt></b>
 269 </p><p>
 270 where <i><tt>machine_name</tt></i> is the machine's NetBIOS
 271 name.  The RID of the new machine account is generated from the UID of
 272 the corresponding Unix account.
 273 </p><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Join the client to the domain immediately</h3><p>
 274         Manually creating a machine trust account using this method is the
 275         equivalent of creating a machine trust account on a Windows NT PDC using
 276         the &quot;Server Manager&quot;.  From the time at which the account is created
 277         to the time which the client joins the domain and changes the password,
 278         your domain is vulnerable to an intruder joining your domain using
 279         a machine with the same NetBIOS name.  A PDC inherently trusts
 280         members of the domain and will serve out a large degree of user
 281         information to such clients.  You have been warned!
 282         </p></div></div><div class="sect2" lang="en"><div class="titlepage"><div><h3 class="title"><a name="id2878262"></a>&quot;On-the-Fly&quot; Creation of Machine Trust Accounts</h3></div></div><p>
 283 The second (and recommended) way of creating machine trust accounts is
 284 simply to allow the Samba server to create them as needed when the client
 285 is joined to the domain. </p><p>Since each Samba machine trust account requires a corresponding
 286 Unix account, a method for automatically creating the
 287 Unix account is usually supplied; this requires configuration of the
 288 <a href="smb.conf.5.html#ADDUSERSCRIPT" target="_top">add user script</a>
 289 option in <tt>smb.conf</tt>.  This
 290 method is not required, however; corresponding Unix accounts may also
 291 be created manually.
 292 </p><p>Below is an example for a RedHat 6.2 Linux system.
 293 </p><pre class="programlisting">
 294 [global]
 295    # &lt;...remainder of parameters...&gt;
 296    add user script = /usr/sbin/useradd -d /dev/null -g 100 -s /bin/false -M %u
 297 </pre></div><div class="sect2" lang="en"><div class="titlepage"><div><h3 class="title"><a name="id2878318"></a>Joining the Client to the Domain</h3></div></div><p>
 298 The procedure for joining a client to the domain varies with the
 299 version of Windows.
 300 </p><div class="itemizedlist"><ul type="disc"><li><p><span class="emphasis"><em>Windows 2000</em></span></p><p>
 301         When the user elects to join the client to a domain, Windows prompts for
 302         an account and password that is privileged to join the domain. A Samba administrative
 303         account (i.e., a Samba account that has root privileges on the Samba server) must be
 304         entered here; the operation will fail if an ordinary user account is given.
 305         The password for this account should be set to a different password than the associated
 306         <tt>/etc/passwd</tt> entry, for security reasons.
 307         </p><p>
 308         The session key of the Samba administrative account acts as an
 309         encryption key for setting the password of the machine trust
 310         account. The machine trust account will be created on-the-fly, or
 311         updated if it already exists.
 312         </p></li><li><p><span class="emphasis"><em>Windows NT</em></span></p><p> If the machine trust account was created manually, on the
 313         Identification Changes menu enter the domain name, but do not
 314         check the box &quot;Create a Computer Account in the Domain.&quot;  In this case,
 315         the existing machine trust account is used to join the machine to
 316         the domain.</p><p> If the machine trust account is to be created
 317         on-the-fly, on the Identification Changes menu enter the domain
 318         name, and check the box &quot;Create a Computer Account in the Domain.&quot;  In
 319         this case, joining the domain proceeds as above for Windows 2000
 320         (i.e., you must supply a Samba administrative account when
 321         prompted).</p></li><li><p><span class="emphasis"><em>Samba</em></span></p><p>Joining a samba client to a domain is documented in
 322         the <a href="domain-member.html" title="Chapter 8. Samba as a NT4 or Win2k domain member">Domain Member</a> chapter.
 323 </p></li></ul></div></div></div><div class="sect1" lang="en"><div class="titlepage"><div><h2 class="title" style="clear: both"><a name="id2878425"></a>Common Problems and Errors</h2></div></div><div class="sect2" lang="en"><div class="titlepage"><div><h3 class="title"><a name="id2878432"></a>I cannot include a '$' in a machine name</h3></div></div><p>
 324 A 'machine name' in (typically) <tt>/etc/passwd</tt>
 325 of the machine name with a '$' appended. FreeBSD (and other BSD
 326 systems?) won't create a user with a '$' in their name.
 327 </p><p>
 328 The problem is only in the program used to make the entry. Once made, it works perfectly.
 329 Create a user without the '$' using <b>vipw</b> to edit the entry, adding
 330 the '$'. Or create the whole entry with vipw if you like, make sure you use a unique User ID!
 331 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><h3 class="title"><a name="id2878470"></a>I get told &quot;You already have a connection to the Domain....&quot;
 332 or &quot;Cannot join domain, the credentials supplied conflict with an
 333 existing set..&quot; when creating a machine trust account.</h3></div></div><p>
 334 This happens if you try to create a machine trust account from the
 335 machine itself and already have a connection (e.g. mapped drive)
 336 to a share (or IPC$) on the Samba PDC.  The following command
 337 will remove all network drive connections:
 338 </p><p>
 339 <tt>C:\WINNT\&gt;</tt> <b>net use * /d</b>
 340 </p><p>
 341 Further, if the machine is already a 'member of a workgroup' that
 342 is the same name as the domain you are joining (bad idea) you will
 343 get this message.  Change the workgroup name to something else, it
 344 does not matter what, reboot, and try again.
 345 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><h3 class="title"><a name="id2878517"></a>The system can not log you on (C000019B)....</h3></div></div><p>I joined the domain successfully but after upgrading
 346 to a newer version of the Samba code I get the message, &quot;The system
 347 can not log you on (C000019B), Please try again or consult your
 348 system administrator&quot; when attempting to logon.
 349 </p><p>
 350 This occurs when the domain SID stored in the secrets.tdb database
 351 is changed. The most common cause of a change in domain SID is when
 352 the domain name and/or the server name (netbios name) is changed.
 353 The only way to correct the problem is to restore the original domain
 354 SID or remove the domain client from the domain and rejoin. The domain
 355 SID may be reset using either the net or rpcclient utilities.
 356 </p><p>
 357 The reset or change the domain SID you can use the net command as follows:
 358
 359 </p><pre class="programlisting">
 360         net getlocalsid 'OLDNAME'
 361         net setlocalsid 'SID'
 362 </pre><p>
 363 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><h3 class="title"><a name="id2878568"></a>The machine trust account for this computer either does not
 364 exist or is not accessible.</h3></div></div><p>
 365 When I try to join the domain I get the message &quot;The machine account
 366 for this computer either does not exist or is not accessible&quot;. What's
 367 wrong?
 368 </p><p>
 369 This problem is caused by the PDC not having a suitable machine trust account.
 370 If you are using the <i><tt>add user script</tt></i> method to create
 371 accounts then this would indicate that it has not worked. Ensure the domain
 372 admin user system is working.
 373 </p><p>
 374 Alternatively if you are creating account entries manually then they
 375 have not been created correctly. Make sure that you have the entry
 376 correct for the machine trust account in smbpasswd file on the Samba PDC.
 377 If you added the account using an editor rather than using the smbpasswd
 378 utility, make sure that the account name is the machine NetBIOS name
 379 with a '$' appended to it ( i.e. computer_name$ ). There must be an entry
 380 in both /etc/passwd and the smbpasswd file. Some people have reported
 381 that inconsistent subnet masks between the Samba server and the NT
 382 client have caused this problem.   Make sure that these are consistent
 383 for both client and server.
 384 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><h3 class="title"><a name="id2878617"></a>When I attempt to login to a Samba Domain from a NT4/W2K workstation,
 385 I get a message about my account being disabled.</h3></div></div><p>
 386 At first be ensure to enable the useraccounts with <b>smbpasswd -e
 387 %user%</b>, this is normally done, when you create an account.
 388 </p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><h2 class="title" style="clear: both"><a name="id2878642"></a>Domain Control for Windows 9x/ME</h2></div></div><p>
 389 A domain and a workgroup are exactly the same thing in terms of network
 390 browsing.  The difference is that a distributable authentication
 391 database is associated with a domain, for secure login access to a
 392 network.  Also, different access rights can be granted to users if they
 393 successfully authenticate against a domain logon server. Samba-3 does this
 394 now in the same way that MS Windows NT/2K.
 395 </p><p>
 396 The SMB client logging on to a domain has an expectation that every other
 397 server in the domain should accept the same authentication information.
 398 Network browsing functionality of domains and workgroups is identical and
 399 is explained in this documentation under the browsing discussions.
 400 It should be noted, that browsing is totally orthogonal to logon support.
 401 </p><p>
 402 Issues related to the single-logon network model are discussed in this
 403 section.  Samba supports domain logons, network logon scripts, and user
 404 profiles for MS Windows for workgroups and MS Windows 9X/ME clients
 405 which are the focus of this section.
 406 </p><p>
 407 When an SMB client in a domain wishes to logon it broadcast requests for a
 408 logon server.  The first one to reply gets the job, and validates its
 409 password using whatever mechanism the Samba administrator has installed.
 410 It is possible (but very stupid) to create a domain where the user
 411 database is not shared between servers, i.e. they are effectively workgroup
 412 servers advertising themselves as participating in a domain.  This
 413 demonstrates how authentication is quite different from but closely
 414 involved with domains.
 415 </p><p>
 416 Using these features you can make your clients verify their logon via
 417 the Samba server; make clients run a batch file when they logon to
 418 the network and download their preferences, desktop and start menu.
 419 </p><p>
 420 Before launching into the configuration instructions, it is
 421 worthwhile to look at how a Windows 9x/ME client performs a logon:
 422 </p><div class="orderedlist"><ol type="1"><li><p>
 423         The client broadcasts (to the IP broadcast address of the subnet it is in)
 424         a NetLogon request. This is sent to the NetBIOS name DOMAIN&lt;1c&gt; at the
 425         NetBIOS layer.  The client chooses the first response it receives, which
 426         contains the NetBIOS name of the logon server to use in the format of
 427         \\SERVER.
 428         </p></li><li><p>
 429         The client then connects to that server, logs on (does an SMBsessetupX) and
 430         then connects to the IPC$ share (using an SMBtconX).
 431         </p></li><li><p>
 432         The client then does a NetWkstaUserLogon request, which retrieves the name
 433         of the user's logon script.
 434         </p></li><li><p>
 435         The client then connects to the NetLogon share and searches for this
 436         and if it is found and can be read, is retrieved and executed by the client.
 437         After this, the client disconnects from the NetLogon share.
 438         </p></li><li><p>
 439         The client then sends a NetUserGetInfo request to the server, to retrieve
 440         the user's home share, which is used to search for profiles. Since the
 441         response to the NetUserGetInfo request does not contain much more then
 442         the user's home share, profiles for Win9X clients MUST reside in the user
 443         home directory.
 444         </p></li><li><p>
 445         The client then connects to the user's home share and searches for the
 446         user's profile. As it turns out, you can specify the user's home share as
 447         a sharename and path. For example, \\server\fred\.profile.
 448         If the profiles are found, they are implemented.
 449         </p></li><li><p>
 450         The client then disconnects from the user's home share, and reconnects to
 451         the NetLogon share and looks for CONFIG.POL, the policies file. If this is
 452         found, it is read and implemented.
 453         </p></li></ol></div><div class="sect2" lang="en"><div class="titlepage"><div><h3 class="title"><a name="id2878805"></a>Configuration Instructions:      Network Logons</h3></div></div><p>
 454 The main difference between a PDC and a Windows 9x logon
 455 server configuration is that
 456 </p><div class="itemizedlist"><ul type="disc"><li><p>
 457 Password encryption is not required for a Windows 9x logon server.
 458 </p></li><li><p>
 459 Windows 9x/ME clients do not possess machine trust accounts.
 460 </p></li></ul></div><p>
 461 Therefore, a Samba PDC will also act as a Windows 9x logon
 462 server.
 463 </p><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">security mode and master browsers</h3><p>
 464 There are a few comments to make in order to tie up some
 465 loose ends.  There has been much debate over the issue of whether
 466 or not it is ok to configure Samba as a Domain Controller in security
 467 modes other than <tt>USER</tt>.  The only security mode
 468 which  will not work due to technical reasons is <tt>SHARE</tt>
 469 mode security.  <tt>DOMAIN</tt> and <tt>SERVER</tt>
 470 mode security is really just a variation on SMB user level security.
 471 </p><p>
 472 Actually, this issue is also closely tied to the debate on whether
 473 or not Samba must be the domain master browser for its workgroup
 474 when operating as a DC.  While it may technically be possible
 475 to configure a server as such (after all, browsing and domain logons
 476 are two distinctly different functions), it is not a good idea to do
 477 so.  You should remember that the DC must register the DOMAIN#1b NetBIOS
 478 name.  This is the name used by Windows clients to locate the DC.
 479 Windows clients do not distinguish between the DC and the DMB.
 480 For this reason, it is very wise to configure the Samba DC as the DMB.
 481 </p><p>
 482 Now back to the issue of configuring a Samba DC to use a mode other
 483 than &quot;security = user&quot;.  If a Samba host is configured to use
 484 another SMB server or DC in order to validate user connection
 485 requests, then it is a fact that some other machine on the network
 486 (the &quot;password server&quot;) knows more about the user than the Samba host.
 487 99% of the time, this other host is a domain controller.  Now
 488 in order to operate in domain mode security, the &quot;workgroup&quot; parameter
 489 must be set to the name of the Windows NT domain (which already
 490 has a domain controller, right?)
 491 </p><p>
 492 Therefore configuring a Samba box as a DC for a domain that
 493 already by definition has a PDC is asking for trouble.
 494 Therefore, you should always configure the Samba DC to be the DMB
 495 for its domain.
 496 </p></div></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="securitylevels.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="type.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="samba-bdc.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 4. Samba as Stand-Alone Server </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 6.
 497 Samba Backup Domain Controller to Samba Domain Control
 498 </td></tr></table></div></body></html>