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1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Chapter 4. Domain Control</title><link rel="stylesheet" href="samba.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.71.0"><link rel="start" href="index.html" title="The Official Samba-3 HOWTO and Reference Guide"><link rel="up" href="type.html" title="Part II. Server Configuration Basics"><link rel="prev" href="ServerType.html" title="Chapter 3. Server Types and Security Modes"><link rel="next" href="samba-bdc.html" title="Chapter 5. Backup Domain Control"></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 4. Domain Control</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ServerType.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><div><h2 class="title"><a name="samba-pdc"></a>Chapter 4. Domain Control</h2></div><div><div class="author"><h3 class="author"><span class="firstname">John</span> <span class="othername">H.</span> <span class="surname">Terpstra</span></h3><div class="affiliation"><span class="orgname">Samba Team<br></span><div class="address"><p><code class="email">&lt;<a href="mailto:jht@samba.org">jht@samba.org</a>&gt;</code></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">Gerald</span> <span class="othername">(Jerry)</span> <span class="surname">Carter</span></h3><div class="affiliation"><span class="orgname">Samba Team<br></span><div class="address"><p><code class="email">&lt;<a href="mailto:jerry@samba.org">jerry@samba.org</a>&gt;</code></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">David</span> <span class="surname">Bannon</span></h3><div class="affiliation"><span class="orgname">Samba Team<br></span><div class="address"><p><code class="email">&lt;<a href="mailto:dbannon@samba.org">dbannon@samba.org</a>&gt;</code></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">Guenther</span> <span class="surname">Deschner</span></h3><span class="contrib">LDAP updates</span><div class="affiliation"><span class="orgname">SuSE<br></span><div class="address"><p><code class="email">&lt;<a href="mailto:gd@suse.de">gd@suse.de</a>&gt;</code></p></div></div></div></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="sect1"><a href="samba-pdc.html#id327668">Features and Benefits</a></span></dt><dt><span class="sect1"><a href="samba-pdc.html#id328244">Single Sign-On and Domain Security</a></span></dt><dt><span class="sect1"><a href="samba-pdc.html#id328748">Basics of Domain Control</a></span></dt><dd><dl><dt><span class="sect2"><a href="samba-pdc.html#id328766">Domain Controller Types</a></span></dt><dt><span class="sect2"><a href="samba-pdc.html#id329223">Preparing for Domain Control</a></span></dt></dl></dd><dt><span class="sect1"><a href="samba-pdc.html#id329677">Domain Control: Example Configuration</a></span></dt><dt><span class="sect1"><a href="samba-pdc.html#id330430">Samba ADS Domain Control</a></span></dt><dt><span class="sect1"><a href="samba-pdc.html#id330473">Domain and Network Logon Configuration</a></span></dt><dd><dl><dt><span class="sect2"><a href="samba-pdc.html#id330490">Domain Network Logon Service</a></span></dt><dt><span class="sect2"><a href="samba-pdc.html#id331027">Security Mode and Master Browsers</a></span></dt></dl></dd><dt><span class="sect1"><a href="samba-pdc.html#id331242">Common Errors</a></span></dt><dd><dl><dt><span class="sect2"><a href="samba-pdc.html#id331248">&#8220;<span class="quote">$</span>&#8221; Cannot Be Included in Machine Name</a></span></dt><dt><span class="sect2"><a href="samba-pdc.html#id331343">Joining Domain Fails Because of Existing Machine Account</a></span></dt><dt><span class="sect2"><a href="samba-pdc.html#id331401">The System Cannot Log You On (C000019B)</a></span></dt><dt><span class="sect2"><a href="samba-pdc.html#id331468">The Machine Trust Account Is Not Accessible</a></span></dt><dt><span class="sect2"><a href="samba-pdc.html#id331569">Account Disabled</a></span></dt><dt><span class="sect2"><a href="samba-pdc.html#id331595">Domain Controller Unavailable</a></span></dt><dt><span class="sect2"><a href="samba-pdc.html#id331611">Cannot Log onto Domain Member Workstation After Joining Domain</a></span></dt></dl></dd></dl></div><p>
2There are many who approach MS Windows networking with incredible misconceptions.
3That's okay, because it gives the rest of us plenty of opportunity to be of assistance.
4Those who really want help are well advised to become familiar with information
5that is already available.
6</p><p>
7<a class="indexterm" name="id327547"></a>
8You are advised not to tackle this section without having first understood
9and mastered some basics. MS Windows networking is not particularly forgiving of
10misconfiguration. Users of MS Windows networking are likely to complain
11of persistent niggles that may be caused by a broken network configuration.
12To a great many people, however, MS Windows networking starts with a domain controller
13that in some magical way is expected to solve all network operational ills.
14</p><p>
15<a href="samba-pdc.html#domain-example" title="Figure 4.1. An Example Domain.">The Example Domain Illustration</a> shows a typical MS Windows domain security
16network environment. Workstations A, B, and C are representative of many physical MS Windows
17network clients.
18</p><div class="figure"><a name="domain-example"></a><p class="title"><b>Figure 4.1. An Example Domain.</b></p><div class="figure-contents"><div class="mediaobject"><img src="images/domain.png" width="216" alt="An Example Domain."></div></div></div><br class="figure-break"><p>
19From the Samba mailing list we can readily identify many common networking issues.
20If you are not clear on the following subjects, then it will do much good to read the
21sections of this HOWTO that deal with it. These are the most common causes of MS Windows
22networking problems:
23</p><div class="itemizedlist"><ul type="disc"><li><p>Basic TCP/IP configuration.</p></li><li><p>NetBIOS name resolution.</p></li><li><p>Authentication configuration.</p></li><li><p>User and group configuration.</p></li><li><p>Basic file and directory permission control in UNIX/Linux.</p></li><li><p>Understanding how MS Windows clients interoperate in a network environment.</p></li></ul></div><p>
24Do not be put off; on the surface of it MS Windows networking seems so simple that anyone
25can do it. In fact, it is not a good idea to set up an MS Windows network with
26inadequate training and preparation. But let's get our first indelible principle out of the
27way: <span class="emphasis"><em>It is perfectly okay to make mistakes!</em></span> In the right place and at
28the right time, mistakes are the essence of learning. It is very much not okay to make
29mistakes that cause loss of productivity and impose an avoidable financial burden on an
30organization.
31</p><p>
32Where is the right place to make mistakes? Only out of harms way. If you are going to
33make mistakes, then please do it on a test network, away from users, and in such a way as
34to not inflict pain on others. Do your learning on a test network.
35</p><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id327668"></a>Features and Benefits</h2></div></div></div><p>
36<a class="indexterm" name="id327676"></a>
37<span class="emphasis"><em>What is the key benefit of Microsoft Domain Security?</em></span>
38</p><p>
39<a class="indexterm" name="id327690"></a>
40<a class="indexterm" name="id327698"></a>
41<a class="indexterm" name="id327705"></a>
42<a class="indexterm" name="id327712"></a>
43In a word, <span class="emphasis"><em>single sign-on</em></span>, or SSO for short. To many, this is the Holy Grail of MS
44Windows NT and beyond networking. SSO allows users in a well-designed network to log onto any workstation that
45is a member of the domain that contains their user account (or in a domain that has an appropriate trust
46relationship with the domain they are visiting) and they will be able to log onto the network and access
47resources (shares, files, and printers) as if they are sitting at their home (personal) workstation. This is a
48feature of the domain security protocols.
49</p><p>
50<a class="indexterm" name="id327735"></a>
51<a class="indexterm" name="id327742"></a>
52<a class="indexterm" name="id327748"></a>
53<a class="indexterm" name="id327757"></a>
54<a class="indexterm" name="id327766"></a>
55The benefits of domain security are available to those sites that deploy a Samba PDC. A domain provides a
56unique network security identifier (SID). Domain user and group security identifiers are comprised of the
57network SID plus a relative identifier (RID) that is unique to the account. User and group SIDs (the network
58SID plus the RID) can be used to create access control lists (ACLs) attached to network resources to provide
59organizational access control. UNIX systems recognize only local security identifiers.
60</p><p>
61<a class="indexterm" name="id327780"></a>
62A SID represents a security context. For example, every Windows machine has local accounts within the security
63context of the local machine which has a unique SID. Every domain (NT4, ADS, Samba) contains accounts that
64exist within the domain security context which is defined by the domain SID.
65</p><p>
66<a class="indexterm" name="id327793"></a>
67<a class="indexterm" name="id327799"></a>
68A domain member server will have a SID that differs from the domain SID. The domain member server can be
69configured to regard all domain users as local users. It can also be configured to recognize domain users and
70groups as non-local. SIDs are persistent. A typical domain of user SID looks like this:
71</p><pre class="screen">
72S-1-5-21-726309263-4128913605-1168186429
73</pre><p>
74Every account (user, group, machine, trust, etc.) is assigned a RID. This is done automatically as an account
75is created. Samba produces the RID algorithmically. The UNIX operating system uses a separate name space for
76user and group identifiers (the UID and GID) but Windows allocates the RID from a single name space. A Windows
77user and a Windows group can not have the same RID. Just as the UNIX user <code class="literal">root</code> has the
78UID=0, the Windows Administrator has the well-known RID=500. The RID is catenated to the Windows domain SID,
79so Administrator account for a domain that has the above SID will have the user SID
80</p><pre class="screen">
81S-1-5-21-726309263-4128913605-1168186429-500
82</pre><p>
83The result is that every account in the Windows networking world has a globally unique security identifier.
84</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
85<a class="indexterm" name="id327837"></a>
86<a class="indexterm" name="id327846"></a>
87<a class="indexterm" name="id327853"></a>
88Network clients of an MS Windows domain security environment must be domain members to be able to gain access
89to the advanced features provided. Domain membership involves more than just setting the workgroup name to the
90domain name. It requires the creation of a domain trust account for the workstation (called a machine
91account). Refer to <a href="domain-member.html" title="Chapter 6. Domain Membership">Domain Membership</a> for more information.
92</p></div><p>
93The following functionalities are new to the Samba-3 release:
94</p><div class="itemizedlist"><ul type="disc"><li><p>
95 <a class="indexterm" name="id327882"></a>
96 Samba-3 supports the use of a choice of backends that may be used in which user, group and machine
97 accounts may be stored. Multiple passwd backends can be used in combination, either as additive backend
98 data sets, or as fail-over data sets.
99 </p><p>
100 <a class="indexterm" name="id327897"></a>
101 <a class="indexterm" name="id327904"></a>
102 <a class="indexterm" name="id327910"></a>
103 <a class="indexterm" name="id327917"></a>
104 <a class="indexterm" name="id327924"></a>
105 An LDAP passdb backend confers the benefit that the account backend can be distributed and replicated,
106 which is of great value because it confers scalability and provides a high degree of reliability.
107 </p></li><li><p>
108 <a class="indexterm" name="id327937"></a>
109 <a class="indexterm" name="id327949"></a>
110 <a class="indexterm" name="id327958"></a>
111 Windows NT4 domain trusts. Samba-3 supports workstation and server (machine) trust accounts. It also
112 supports Windows NT4 style interdomain trust accounts, which further assists in network scalability
113 and interoperability.
114 </p></li><li><p>
115 <a class="indexterm" name="id327971"></a>
116 <a class="indexterm" name="id327978"></a>
117 <a class="indexterm" name="id327984"></a>
118 <a class="indexterm" name="id327991"></a>
119 <a class="indexterm" name="id328000"></a>
120 <a class="indexterm" name="id328010"></a>
121 Operation without NetBIOS over TCP/IP, rather using the raw SMB over TCP/IP. Note, this is feasible
122 only when operating as a Microsoft active directory domain member server. When acting as a Samba domain
123 controller the use of NetBIOS is necessary to provide network browsing support.
124 </p></li><li><p>
125 <a class="indexterm" name="id328026"></a>
126 <a class="indexterm" name="id328032"></a>
127 <a class="indexterm" name="id328039"></a>
128 Samba-3 provides NetBIOS name services (WINS), NetBIOS over TCP/IP (TCP port 139) session services, SMB over
129 TCP/IP (TCP port 445) session services, and Microsoft compatible ONC DCE RPC services (TCP port 135)
130 services.
131 </p></li><li><p>
132 <a class="indexterm" name="id328052"></a>
133 Management of users and groups via the User Manager for Domains. This can be done on any MS Windows client
134 using the <code class="filename">Nexus.exe</code> toolkit for Windows 9x/Me, or using the SRVTOOLS.EXE package for MS
135 Windows NT4/200x/XP platforms. These packages are available from Microsoft's Web site.
136 </p></li><li><p>
137 Implements full Unicode support. This simplifies cross-locale internationalization support. It also opens up
138 the use of protocols that Samba-2.2.x had but could not use due to the need to fully support Unicode.
139 </p></li></ul></div><p>
140The following functionalities are not provided by Samba-3:
141</p><div class="itemizedlist"><ul type="disc"><li><p>
142 <a class="indexterm" name="id328085"></a>
143 <a class="indexterm" name="id328092"></a>
144 SAM replication with Windows NT4 domain controllers (i.e., a Samba PDC and a Windows NT BDC, or vice versa).
145 This means Samba cannot operate as a BDC when the PDC is Microsoft-based Windows NT PDC. Samba-3 can not
146 participate in replication of account data to Windows PDCs and BDCs.
147 </p></li><li><p>
148 <a class="indexterm" name="id328105"></a>
149 <a class="indexterm" name="id328112"></a>
150 Acting as a Windows 2000 active directory domain controller (i.e., Kerberos and Active Directory). In point of
151 fact, Samba-3 does have some Active Directory domain control ability that is at this time purely experimental.
152 Active directory domain control is one of the features that is being developed in Samba-4, the next
153 generation Samba release. At this time there are no plans to enable active directory domain control
154 support during the Samba-3 series life-cycle.
155 </p></li><li><p>
156 <a class="indexterm" name="id328131"></a>
157 <a class="indexterm" name="id328138"></a>
158 <a class="indexterm" name="id328144"></a>
159 The Windows 200x/XP Microsoft Management Console (MMC) cannot be used to manage a Samba-3 server. For this you
160 can use only the MS Windows NT4 Domain Server Manager and the MS Windows NT4 Domain User Manager. Both are
161 part of the SVRTOOLS.EXE package mentioned later.
162 </p></li></ul></div><p>
163<a class="indexterm" name="id328160"></a>
164<a class="indexterm" name="id328167"></a>
165Windows 9x/Me/XP Home clients are not true members of a domain for reasons outlined in this chapter. The
166protocol for support of Windows 9x/Me-style network (domain) logons is completely different from NT4/Windows
167200x-type domain logons and has been officially supported for some time. These clients use the old LanMan
168network logon facilities that are supported in Samba since approximately the Samba-1.9.15 series.
169</p><p>
170<a class="indexterm" name="id328180"></a>
171Samba-3 implements group mapping between Windows NT groups and UNIX groups (this is really quite complicated
172to explain in a short space). This is discussed more fully in <a href="groupmapping.html" title="Chapter 12. Group Mapping: MS Windows and UNIX">Group Mapping: MS
173Windows and UNIX</a>.
174</p><p>
175<a class="indexterm" name="id328202"></a>
176<a class="indexterm" name="id328208"></a>
177<a class="indexterm" name="id328217"></a>
178Samba-3, like an MS Windows NT4 PDC or a Windows 200x Active Directory, needs to store user and Machine Trust
179Account information in a suitable backend data-store. Refer to <a href="domain-member.html#machine-trust-accounts" title="MS Windows Workstation/Server Machine Trust Accounts">MS
180Windows Workstation/Server Machine Trust Accounts</a>. With Samba-3 there can be multiple backends for
181this. A complete discussion of account database backends can be found in <a href="passdb.html" title="Chapter 11. Account Information Databases">Account
182Information Databases</a>.
183</p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id328244"></a>Single Sign-On and Domain Security</h2></div></div></div><p>
184<a class="indexterm" name="id328252"></a>
185<a class="indexterm" name="id328260"></a>
186<a class="indexterm" name="id328267"></a>
187<a class="indexterm" name="id328274"></a>
188<a class="indexterm" name="id328280"></a>
189<a class="indexterm" name="id328287"></a>
190<a class="indexterm" name="id328294"></a>
191When network administrators are asked to describe the benefits of Windows NT4 and active directory networking
192the most often mentioned feature is that of single sign-on (SSO). Many companies have implemented SSO
193solutions. The mode of implementation of a single sign-on solution is an important factor in the practice of
194networking in general, and is critical in respect of Windows networking. A company may have a wide variety of
195information systems, each of which requires a form of user authentication and validation, thus it is not
196uncommon that users may need to remember more than ten login IDs and passwords. This problem is compounded
197when the password for each system must be changed at regular intervals, and particularly so where password
198uniqueness and history limits are applied.
199</p><p>
200<a class="indexterm" name="id328311"></a>
201There is a broadly held perception that SSO is the answer to the problem of users having to deal with too many
202information system access credentials (username/password pairs). Many elaborate schemes have been devised to
203make it possible to deliver a user-friendly SSO solution. The trouble is that if this implementation is not
204done correctly, the site may end up paying dearly by way of complexity and management overheads. Simply put,
205many SSO solutions are an administrative nightmare.
206</p><p>
207<a class="indexterm" name="id328325"></a>
208<a class="indexterm" name="id328332"></a>
209<a class="indexterm" name="id328339"></a>
210SSO implementations utilize centralization of all user account information. Depending on environmental
211complexity and the age of the systems over which a SSO solution is implemented, it may not be possible to
212change the solution architecture so as to accomodate a new identity management and user authentication system.
213Many SSO solutions involving legacy systems consist of a new super-structure that handles authentication on
214behalf of the user. The software that gets layered over the old system may simply implement a proxy
215authentication system. This means that the addition of SSO increases over-all information systems complexity.
216Ideally, the implementation of SSO should reduce complexity and reduce administative overheads.
217</p><p>
218<a class="indexterm" name="id328355"></a>
219<a class="indexterm" name="id328362"></a>
220<a class="indexterm" name="id328371"></a>
221<a class="indexterm" name="id328380"></a>
222<a class="indexterm" name="id328387"></a>
223The initial goal of many network administrators is often to create and use a centralized identity management
224system. It is often assumed that such a centralized system will use a single authentication infrastructure
225that can be used by all information systems. The Microsoft Windows NT4 security domain architecture and the
226Micrsoft active directory service are often put forward as the ideal foundation for such a system. It is
227conceptually simple to install an external authentication agent on each of the disparate infromation systems
228that can then use the Microsoft (NT4 domain or ads service) for user authentication and access control. The
229wonderful dream of a single centralized authentication service is commonly broken when realities are realized.
230The problem with legacy systems is often the inability to externalize the authentication and access control
231system it uses because its implementation will be excessively invasive from a re-engineering perspective, or
232because application software has built-in dependencies on particular elements of the way user authentication
233and access control were designed and built.
234</p><p>
235<a class="indexterm" name="id328406"></a>
236<a class="indexterm" name="id328413"></a>
237<a class="indexterm" name="id328420"></a>
238<a class="indexterm" name="id328427"></a>
239<a class="indexterm" name="id328434"></a>
240<a class="indexterm" name="id328441"></a>
241<a class="indexterm" name="id328447"></a>
242<a class="indexterm" name="id328454"></a>
243Over the past decade an industry has been developed around the various methods that have been built to get
244around the key limitations of legacy information technology systems. One approach that is often used involves
245the use of a meta-directory. The meta-directory stores user credentials for all disparate information systems
246in the format that is particular to each system. An elaborate set of management procedures is coupled with a
247rigidly enforced work-flow protocol for managing user rights and privileges within the maze of systems that
248are provisioned by the new infrastructure makes possible user access to all systems using a single set of user
249credentials.
250</p><p>
251<a class="indexterm" name="id328476"></a>
252<a class="indexterm" name="id328485"></a>
253<a class="indexterm" name="id328494"></a>
254<a class="indexterm" name="id328504"></a>
255The Organization for the Advancement of Structured Information Standards (OASIS) has developed the Security
256Assertion Markup Language (SAML), a structured method for communication of authentication information. The
257over-all umbrella name for the technologies and methods that deploy SAML is called Federated Identity
258Management (FIM). FIM depends on each system in the complex maze of disparate information systems to
259authenticate their respective users and vouch for secure access to the services each provides.
260</p><p>
261<a class="indexterm" name="id328518"></a>
262<a class="indexterm" name="id328527"></a>
263<a class="indexterm" name="id328534"></a>
264<a class="indexterm" name="id328541"></a>
265<a class="indexterm" name="id328548"></a>
266<a class="indexterm" name="id328553"></a>
267SAML documents can be wrapped in a Simple Object Access Protocol (SOAP) message for the computer-to-computer
268communications needed for Web services. Or they may be passed between Web servers of federated organizations
269that share live services. The Liberty Alliance, an industry group formed to promote federated-identity
270standards, has adopted SAML 1.1 as part of its application framework. Microsoft and IBM have proposed an
271alternative specification called WS-Security. Some believe that the competing technologies and methods may
272converge when the SAML 2.0 standard is introduced. A few Web access-management products support SAML today,
273but implemention of the technology mostly requires customization to integrate applications and develop user
274interfaces. In a nust-shell, that is why FIM is a big and growing industry.
275</p><p>
276<a class="indexterm" name="id328569"></a>
277<a class="indexterm" name="id328576"></a>
278<a class="indexterm" name="id328582"></a>
279<a class="indexterm" name="id328589"></a>
280<a class="indexterm" name="id328596"></a>
281Ignoring the bigger picture, which is beyond the scope of this book, the migration of all user and group
282management to a centralized system is a step in the right direction. It is essential for interoperability
283reasons to locate the identity management system data in a directory such as Microsoft Active Directory
284Service (ADS), or any proprietary or open source system that provides a standard protocol for information
285access (such as LDAP) and that can be coupled with a flexible array of authentication mechanisms (such as
286kerberos) that use the protocols that are defined by the various general security service application
287programming interface (GSSAPI) services.
288</p><p>
289<a class="indexterm" name="id328614"></a>
290<a class="indexterm" name="id328621"></a>
291<a class="indexterm" name="id328628"></a>
292A growing number of companies provide authentication agents for disparate legacy platforms to permit the use
293of LDAP systems. Thus the use of OpenLDAP, the dominant open source software implementation of the light
294weight directory access protocol standard. This fact, means that by providing support in Samba for the use of
295LDAP and Microsoft ADS make Samba a highly scalable and forward reaching organizational networking technology.
296</p><p>
297<a class="indexterm" name="id328641"></a>
298<a class="indexterm" name="id328648"></a>
299<a class="indexterm" name="id328655"></a>
300<a class="indexterm" name="id328662"></a>
301<a class="indexterm" name="id328668"></a>
302<a class="indexterm" name="id328675"></a>
303Microsoft ADS provides purely proprietary services that, with limitation, can be extended to provide a
304centralized authentication infrastructure. Samba plus LDAP provides a similar opportunity for extension of a
305centralized authentication architecture, but it is the fact that the Samba Team are pro-active in introducing
306the extension of authentication services, using LDAP or otherwise, to applications such as SQUID (the open
307source proxy server) through tools such as the <code class="literal">ntlm_auth</code> utility, that does much to create
308sustainable choice and competition in the FIM market place.
309</p><p>
310<a class="indexterm" name="id328696"></a>
311<a class="indexterm" name="id328703"></a>
312<a class="indexterm" name="id328709"></a>
313Primary domain control, if it is to be scalable to meet the needs of large sites, must therefore be capable of
314using LDAP. The rapid adoption of OpenLDAP, and Samba configurations that use it, is ample proof that the era
315of the directoy has started. Samba-3 does not demand the use of LDAP, but the demand for a mechanism by which
316user and group identity information can be distributed makes it an an unavoidable option.
317</p><p>
318<a class="indexterm" name="id328723"></a>
319<a class="indexterm" name="id328730"></a>
320<a class="indexterm" name="id328736"></a>
321At this time, the use of Samba based BDCs, necessitates the use of LDAP. The most commonly used LDAP
322implementation used by Samba sites is OpenLDAP. It is possible to use any standards compliant LDAP server.
323Those known to work includes those manufactured by: IBM, CA, Novell (e-Directory), and others.
324</p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id328748"></a>Basics of Domain Control</h2></div></div></div><p>
325<a class="indexterm" name="id328756"></a>
326Over the years, public perceptions of what domain control really is has taken on an almost mystical nature.
327Before we branch into a brief overview of domain control, there are three basic types of domain controllers.
328</p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id328766"></a>Domain Controller Types</h3></div></div></div><div class="itemizedlist"><ul type="disc"><li><p>NT4 style Primary Domain Controller</p></li><li><p>NT4 style Backup Domain Controller</p></li><li><p>ADS Domain Controller</p></li></ul></div><p>
329<a class="indexterm" name="id328790"></a>
330<a class="indexterm" name="id328797"></a>
331<a class="indexterm" name="id328804"></a>
332<a class="indexterm" name="id328813"></a>
333The <span class="emphasis"><em>Primary Domain Controller</em></span> or PDC plays an important role in MS Windows NT4. In
334Windows 200x domain control architecture, this role is held by domain controllers. Folklore dictates that
335because of its role in the MS Windows network, the domain controller should be the most powerful and most
336capable machine in the network. As strange as it may seem to say this here, good overall network performance
337dictates that the entire infrastructure needs to be balanced. It is advisable to invest more in standalone
338(domain member) servers than in the domain controllers.
339</p><p>
340<a class="indexterm" name="id328836"></a>
341<a class="indexterm" name="id328843"></a>
342<a class="indexterm" name="id328849"></a>
343<a class="indexterm" name="id328856"></a>
344<a class="indexterm" name="id328863"></a>
345In the case of MS Windows NT4-style domains, it is the PDC that initiates a new domain control database.
346This forms a part of the Windows registry called the Security Account Manager (SAM). It plays a key
347part in NT4-type domain user authentication and in synchronization of the domain authentication
348database with BDCs.
349</p><p>
350<a class="indexterm" name="id328878"></a>
351<a class="indexterm" name="id328890"></a>
352<a class="indexterm" name="id328896"></a>
353<a class="indexterm" name="id328906"></a>
354With MS Windows 200x Server-based Active Directory domains, one domain controller initiates a potential
355hierarchy of domain controllers, each with its own area of delegated control. The master domain
356controller has the ability to override any downstream controller, but a downline controller has
357control only over its downline. With Samba-3, this functionality can be implemented using an
358LDAP-based user and machine account backend.
359</p><p>
360<a class="indexterm" name="id328919"></a>
361<a class="indexterm" name="id328926"></a>
362New to Samba-3 is the ability to use a backend database that holds the same type of data as the NT4-style SAM
363database (one of the registry files)<sup>[<a name="id328934" href="#ftn.id328934">1</a>]</sup>
364</p><p>
365<a class="indexterm" name="id328950"></a>
366<a class="indexterm" name="id328956"></a>
367<a class="indexterm" name="id328963"></a>
368<a class="indexterm" name="id328970"></a>
369<a class="indexterm" name="id328977"></a>
370<a class="indexterm" name="id328983"></a>
371The <span class="emphasis"><em>Backup Domain Controller</em></span> or BDC plays a key role in servicing network authentication
372requests. The BDC is biased to answer logon requests in preference to the PDC. On a network segment that has
373a BDC and a PDC, the BDC will most likely service network logon requests. The PDC will answer network logon
374requests when the BDC is too busy (high load). When a user logs onto a Windows domain member client the
375workstation will query the network to locate the nearest network logon server. Where a WINS server is used,
376this is done via a query to the WINS server. If a netlogon server can not be found from the WINS query, or in
377the absence of a WINS server, the workstation will perform a NetBIOS name lookup via a mailslot broadcast over
378the UDP broadcast protocol. This means that the netlogon server that the windows client will use is influenced
379by a number of variables, thus there is no simple determinant of whether a PDC or a BDC will serve a
380particular logon authentication request.
381</p><p>
382<a class="indexterm" name="id329005"></a>
383<a class="indexterm" name="id329012"></a>
384A Windows NT4 BDC can be promoted to a PDC. If the PDC is online at the time that a BDC is promoted to PDC,
385the previous PDC is automatically demoted to a BDC. With Samba-3, this is not an automatic operation; the PDC
386and BDC must be manually configured, and other appropriate changes also need to be made.
387</p><p>
388<a class="indexterm" name="id329025"></a>
389With MS Windows NT4, a decision is made at installation to determine what type of machine the server will be.
390It is possible to promote a BDC to a PDC, and vice versa. The only method Microsoft provide to convert a
391Windows NT4 domain controller to a domain member server or a standalone server is to reinstall it. The install
392time choices offered are:
393</p><div class="itemizedlist"><ul type="disc"><li><p><span class="emphasis"><em>Primary Domain Controller</em></span> the one that seeds the domain SAM.</p></li><li><p><span class="emphasis"><em>Backup Domain Controller</em></span> one that obtains a copy of the domain SAM.</p></li><li><p><span class="emphasis"><em>Domain Member Server</em></span> one that has no copy of the domain SAM; rather
394 it obtains authentication from a domain controller for all access controls.</p></li><li><p><span class="emphasis"><em>Standalone Server</em></span> one that plays no part in SAM synchronization,
395 has its own authentication database, and plays no role in domain security.</p></li></ul></div><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
396<a class="indexterm" name="id329088"></a>
397Algin Technology LLC provide a commercial tool that makes it possible to promote a Windows NT4 standalone
398server to a PDC or a BDC, and also permits this process to be reversed. Refer to the <a href="http://utools.com/UPromote.asp" target="_top">Algin</a> web site for further information.
399</p></div><p>
400<a class="indexterm" name="id329105"></a>
401<a class="indexterm" name="id329117"></a>
402Samba-3 servers can readily be converted to and from domain controller roles through simple changes to the
403<code class="filename">smb.conf</code> file. Samba-3 is capable of acting fully as a native member of a Windows 200x server Active
404Directory domain.
405</p><p>
406<a class="indexterm" name="id329135"></a>
407For the sake of providing a complete picture, MS Windows 2000 domain control configuration is done after the server has been
408installed. Please refer to Microsoft documentation for the procedures that should be followed to convert a
409domain member server to or from a domain control, and to install or remove active directory service support.
410</p><p>
411<a class="indexterm" name="id329150"></a>
412<a class="indexterm" name="id329159"></a>
413New to Samba-3 is the ability to function fully as an MS Windows NT4-style domain controller,
414excluding the SAM replication components. However, please be aware that Samba-3 also supports the
415MS Windows 200x domain control protocols.
416</p><p>
417<a class="indexterm" name="id329173"></a>
418At this time any appearance that Samba-3 is capable of acting as a <span class="emphasis"><em>domain controller</em></span> in
419native ADS mode is limited and experimental in nature. This functionality should not be used until the Samba
420Team offers formal support for it. At such a time, the documentation will be revised to duly reflect all
421configuration and management requirements. Samba can act as a NT4-style domain controller in a Windows 2000/XP
422environment. However, there are certain compromises:
423</p><div class="itemizedlist"><ul type="disc"><li><p>No machine policy files.</p></li><li><p>No Group Policy Objects.</p></li><li><p>No synchronously executed Active Directory logon scripts.</p></li><li><p>Can't use Active Directory management tools to manage users and machines.</p></li><li><p>Registry changes tattoo the main registry, while with Active Directory they do not leave
424 permanent changes in effect.</p></li><li><p>Without Active Directory you cannot perform the function of exporting specific
425 applications to specific users or groups.</p></li></ul></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id329223"></a>Preparing for Domain Control</h3></div></div></div><p>
426<a class="indexterm" name="id329231"></a>
427<a class="indexterm" name="id329237"></a>
428<a class="indexterm" name="id329244"></a>
429<a class="indexterm" name="id329251"></a>
430There are two ways that MS Windows machines may interact with each other, with other servers,
431and with domain controllers: either as <span class="emphasis"><em>standalone</em></span> systems, more commonly
432called <span class="emphasis"><em>workgroup</em></span> members, or as full participants in a security system,
433more commonly called <span class="emphasis"><em>domain</em></span> members.
434</p><p>
435<a class="indexterm" name="id329274"></a>
436<a class="indexterm" name="id329281"></a>
437<a class="indexterm" name="id329290"></a>
438It should be noted that workgroup membership involves no special configuration other than the machine being
439configured so the network configuration has a commonly used name for its workgroup entry. It is not uncommon
440for the name WORKGROUP to be used for this. With this mode of configuration, there are no Machine Trust
441Accounts, and any concept of membership as such is limited to the fact that all machines appear in the network
442neighborhood to be logically grouped together. Again, just to be clear: <span class="emphasis"><em>workgroup mode does not
443involve security machine accounts</em></span>.
444</p><p>
445<a class="indexterm" name="id329308"></a>
446<a class="indexterm" name="id329315"></a>
447<a class="indexterm" name="id329324"></a>
448Domain member machines have a machine trust account in the domain accounts database. A special procedure
449must be followed on each machine to effect domain membership. This procedure, which can be done
450only by the local machine Administrator account, creates the domain machine account (if it does
451not exist), and then initializes that account. When the client first logs onto the
452domain, a machine trust account password change will be automatically triggered.
453</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
454<a class="indexterm" name="id329339"></a>
455When Samba is configured as a domain controller, secure network operation demands that
456all MS Windows NT4/200x/XP Professional clients should be configured as domain members.
457If a machine is not made a member of the domain, then it will operate like a workgroup
458(standalone) machine. Please refer to <a href="domain-member.html" title="Chapter 6. Domain Membership">Domain Membership</a>, for
459information regarding domain membership.
460</p></div><p>
461The following are necessary for configuring Samba-3 as an MS Windows NT4-style PDC for MS Windows
462NT4/200x/XP clients:
463</p><div class="itemizedlist"><ul type="disc"><li><p>Configuration of basic TCP/IP and MS Windows networking.</p></li><li><p>Correct designation of the server role (<a class="indexterm" name="id329372"></a>security = user).</p></li><li><p>Consistent configuration of name resolution.<sup>[<a name="id329384" href="#ftn.id329384">2</a>]</sup></p></li><li><p>Domain logons for Windows NT4/200x/XP Professional clients.</p></li><li><p>Configuration of roaming profiles or explicit configuration to force local profile usage.</p></li><li><p>Configuration of network/system policies.</p></li><li><p>Adding and managing domain user accounts.</p></li><li><p>Configuring MS Windows NT4/2000 Professional and Windows XP Professional client machines to become domain members.</p></li></ul></div><p>
464The following provisions are required to serve MS Windows 9x/Me clients:
465</p><div class="itemizedlist"><ul type="disc"><li><p>Configuration of basic TCP/IP and MS Windows networking.</p></li><li><p>Correct designation of the server role (<a class="indexterm" name="id329444"></a>security = user).</p></li><li><p>Network logon configuration (since Windows 9x/Me/XP Home are not technically domain
466 members, they do not really participate in the security aspects of Domain logons as such).</p></li><li><p>Roaming profile configuration.</p></li><li><p>Configuration of system policy handling.</p></li><li><p>Installation of the network driver &#8220;<span class="quote">Client for MS Windows Networks</span>&#8221; and configuration
467 to log onto the domain.</p></li><li><p>Placing Windows 9x/Me clients in user-level security if it is desired to allow
468 all client-share access to be controlled according to domain user/group identities.</p></li><li><p>Adding and managing domain user accounts.</p></li></ul></div><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
469<a class="indexterm" name="id329494"></a>
470<a class="indexterm" name="id329500"></a>
471Roaming profiles and system/network policies are advanced network administration topics
472that are covered in <a href="ProfileMgmt.html" title="Chapter 27. Desktop Profile Management">Desktop Profile Management</a> and
473<a href="PolicyMgmt.html" title="Chapter 26. System and Account Policies">System and Account Policies</a> of this document. However, these are not
474necessarily specific to a Samba PDC as much as they are related to Windows NT networking concepts.
475</p></div><p>
476A domain controller is an SMB/CIFS server that:
477</p><div class="itemizedlist"><ul type="disc"><li><p>
478 <a class="indexterm" name="id329534"></a>
479 <a class="indexterm" name="id329542"></a>
480 <a class="indexterm" name="id329549"></a>
481 <a class="indexterm" name="id329556"></a>
482 <a class="indexterm" name="id329563"></a>
483 Registers and advertises itself as a domain controller (through NetBIOS broadcasts
484 as well as by way of name registrations either by Mailslot Broadcasts over UDP broadcast,
485 to a WINS server over UDP unicast, or via DNS and Active Directory).
486 </p></li><li><p>
487 <a class="indexterm" name="id329576"></a>
488 <a class="indexterm" name="id329583"></a>
489 Provides the NETLOGON service. (This is actually a collection of services that runs over
490 multiple protocols. These include the LanMan logon service, the Netlogon service,
491 the Local Security Account service, and variations of them.)
492 </p></li><li><p>
493 Provides a share called NETLOGON.
494 </p></li></ul></div><p>
495<a class="indexterm" name="id329600"></a>
496<a class="indexterm" name="id329612"></a>
497<a class="indexterm" name="id329624"></a>
498<a class="indexterm" name="id329630"></a>
499<a class="indexterm" name="id329637"></a>
500It is rather easy to configure Samba to provide these. Each Samba domain controller must provide the NETLOGON
501service that Samba calls the <a class="indexterm" name="id329645"></a>domain logons functionality (after the name of the
502parameter in the <code class="filename">smb.conf</code> file). Additionally, one server in a Samba-3 domain must advertise itself as the
503domain master browser.<sup>[<a name="id329659" href="#ftn.id329659">3</a>]</sup> This causes the PDC to claim a domain-specific NetBIOS name that identifies
504it as a DMB for its given domain or workgroup. Local master browsers (LMBs) in the same domain or workgroup on
505broadcast-isolated subnets then ask for a complete copy of the browse list for the whole wide-area network.
506Browser clients then contact their LMB, and will receive the domain-wide browse list instead of just the list
507for their broadcast-isolated subnet.
508</p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id329677"></a>Domain Control: Example Configuration</h2></div></div></div><p>
509The first step in creating a working Samba PDC is to understand the parameters necessary
510in <code class="filename">smb.conf</code>. An example <code class="filename">smb.conf</code> for acting as a PDC can be found in <a href="samba-pdc.html#pdc-example" title="Example 4.1. smb.conf for being a PDC">the
511smb.conf file for an example PDC</a>.
512</p><div class="example"><a name="pdc-example"></a><p class="title"><b>Example 4.1. smb.conf for being a PDC</b></p><div class="example-contents"><table class="simplelist" border="0" summary="Simple list"><tr><td> </td></tr><tr><td><em class="parameter"><code>[global]</code></em></td></tr><tr><td><a class="indexterm" name="id329730"></a><em class="parameter"><code>netbios name</code></em></td></tr><tr><td><a class="indexterm" name="id329743"></a><em class="parameter"><code>workgroup</code></em></td></tr><tr><td><a class="indexterm" name="id329755"></a><em class="parameter"><code>passdb backend = tdbsam</code></em></td></tr><tr><td><a class="indexterm" name="id329768"></a><em class="parameter"><code>os level = 33</code></em></td></tr><tr><td><a class="indexterm" name="id329780"></a><em class="parameter"><code>preferred master = auto</code></em></td></tr><tr><td><a class="indexterm" name="id329793"></a><em class="parameter"><code>domain master = yes</code></em></td></tr><tr><td><a class="indexterm" name="id329805"></a><em class="parameter"><code>local master = yes</code></em></td></tr><tr><td><a class="indexterm" name="id329818"></a><em class="parameter"><code>security = user</code></em></td></tr><tr><td><a class="indexterm" name="id329830"></a><em class="parameter"><code>domain logons = yes</code></em></td></tr><tr><td><a class="indexterm" name="id329843"></a><em class="parameter"><code>logon path = \\%N\profiles\%U</code></em></td></tr><tr><td><a class="indexterm" name="id329856"></a><em class="parameter"><code>logon drive = H:</code></em></td></tr><tr><td><a class="indexterm" name="id329868"></a><em class="parameter"><code>logon home = \\homeserver\%U\winprofile</code></em></td></tr><tr><td><a class="indexterm" name="id329881"></a><em class="parameter"><code>logon script = logon.cmd</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[netlogon]</code></em></td></tr><tr><td><a class="indexterm" name="id329902"></a><em class="parameter"><code>path = /var/lib/samba/netlogon</code></em></td></tr><tr><td><a class="indexterm" name="id329915"></a><em class="parameter"><code>read only = yes</code></em></td></tr><tr><td><a class="indexterm" name="id329928"></a><em class="parameter"><code>write list</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[profiles]</code></em></td></tr><tr><td><a class="indexterm" name="id329949"></a><em class="parameter"><code>path = /var/lib/samba/profiles</code></em></td></tr><tr><td><a class="indexterm" name="id329962"></a><em class="parameter"><code>read only = no</code></em></td></tr><tr><td><a class="indexterm" name="id329974"></a><em class="parameter"><code>create mask = 0600</code></em></td></tr><tr><td><a class="indexterm" name="id329987"></a><em class="parameter"><code>directory mask = 0700</code></em></td></tr></table></div></div><br class="example-break"><p>
513The basic options shown in <a href="samba-pdc.html#pdc-example" title="Example 4.1. smb.conf for being a PDC">this example</a> are explained as follows:
514</p><div class="variablelist"><dl><dt><span class="term">passdb backend </span></dt><dd><p>
515 <a class="indexterm" name="id330021"></a>
516 <a class="indexterm" name="id330030"></a>
517 <a class="indexterm" name="id330037"></a>
518 <a class="indexterm" name="id330044"></a>
519 <a class="indexterm" name="id330051"></a>
520 <a class="indexterm" name="id330057"></a>
521 This contains all the user and group account information. Acceptable values for a PDC
522 are: <span class="emphasis"><em>smbpasswd, tdbsam, and ldapsam</em></span>. The &#8220;<span class="quote">guest</span>&#8221; entry provides
523 default accounts and is included by default; there is no need to add it explicitly.
524 </p><p>
525 <a class="indexterm" name="id330077"></a>
526 <a class="indexterm" name="id330084"></a>
527 <a class="indexterm" name="id330090"></a>
528 <a class="indexterm" name="id330097"></a>
529 Where use of BDCs is intended, the only logical choice is
530 to use LDAP so the passdb backend can be distributed. The tdbsam and smbpasswd files
531 cannot effectively be distributed and therefore should not be used.
532 </p></dd><dt><span class="term">Domain Control Parameters </span></dt><dd><p>
533 <a class="indexterm" name="id330116"></a>
534 <a class="indexterm" name="id330123"></a>
535 <a class="indexterm" name="id330130"></a>
536 <a class="indexterm" name="id330136"></a>
537 The parameters <span class="emphasis"><em>os level, preferred master, domain master, security,
538 encrypt passwords</em></span>, and <span class="emphasis"><em>domain logons</em></span> play a central role in assuring domain
539 control and network logon support.
540 </p><p>
541 <a class="indexterm" name="id330158"></a>
542 <a class="indexterm" name="id330164"></a>
543 The <span class="emphasis"><em>os level</em></span> must be set at or above a value of 32. A domain controller
544 must be the DMB, must be set in <span class="emphasis"><em>user</em></span> mode security,
545 must support Microsoft-compatible encrypted passwords, and must provide the network logon
546 service (domain logons). Encrypted passwords must be enabled. For more details on how
547 to do this, refer to <a href="passdb.html" title="Chapter 11. Account Information Databases">Account Information Databases</a>.
548 </p></dd><dt><span class="term">Environment Parameters </span></dt><dd><p>
549 <a class="indexterm" name="id330198"></a>
550 <a class="indexterm" name="id330205"></a>
551 <a class="indexterm" name="id330212"></a>
552 <a class="indexterm" name="id330218"></a>
553 The parameters <span class="emphasis"><em>logon path, logon home, logon drive</em></span>, and <span class="emphasis"><em>logon script</em></span> are
554 environment support settings that help to facilitate client logon operations and that help
555 to provide automated control facilities to ease network management overheads. Please refer
556 to the man page information for these parameters.
557 </p></dd><dt><span class="term">NETLOGON Share </span></dt><dd><p>
558 <a class="indexterm" name="id330245"></a>
559 <a class="indexterm" name="id330252"></a>
560 <a class="indexterm" name="id330258"></a>
561 <a class="indexterm" name="id330265"></a>
562 <a class="indexterm" name="id330272"></a>
563 <a class="indexterm" name="id330279"></a>
564 The NETLOGON share plays a central role in domain logon and domain membership support.
565 This share is provided on all Microsoft domain controllers. It is used to provide logon
566 scripts, to store group policy files (NTConfig.POL), as well as to locate other common
567 tools that may be needed for logon processing. This is an essential share on a domain controller.
568 </p></dd><dt><span class="term">PROFILE Share </span></dt><dd><p>
569 <a class="indexterm" name="id330299"></a>
570 <a class="indexterm" name="id330305"></a>
571 <a class="indexterm" name="id330312"></a>
572 <a class="indexterm" name="id330319"></a>
573 <a class="indexterm" name="id330326"></a>
574 This share is used to store user desktop profiles. Each user must have a directory at the root
575 of this share. This directory must be write-enabled for the user and must be globally read-enabled.
576 Samba-3 has a VFS module called &#8220;<span class="quote">fake_permissions</span>&#8221; that may be installed on this share. This will
577 allow a Samba administrator to make the directory read-only to everyone. Of course this is useful
578 only after the profile has been properly created.
579 </p></dd></dl></div><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
580The above parameters make for a full set of functionality that may define the server's mode
581of operation. The following <code class="filename">smb.conf</code> parameters are the essentials alone:
582</p><p>
583</p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id330361"></a><em class="parameter"><code>netbios name = BELERIAND</code></em></td></tr><tr><td><a class="indexterm" name="id330374"></a><em class="parameter"><code>workgroup = MIDEARTH</code></em></td></tr><tr><td><a class="indexterm" name="id330386"></a><em class="parameter"><code>domain logons = Yes</code></em></td></tr><tr><td><a class="indexterm" name="id330399"></a><em class="parameter"><code>domain master = Yes</code></em></td></tr><tr><td><a class="indexterm" name="id330411"></a><em class="parameter"><code>security = User</code></em></td></tr></table><p>
584</p><p>
585The additional parameters shown in the longer listing in this section just make for
586a more complete explanation.
587</p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id330430"></a>Samba ADS Domain Control</h2></div></div></div><p>
588<a class="indexterm" name="id330438"></a>
589Samba-3 is not, and cannot act as, an Active Directory server. It cannot truly function as an Active Directory
590PDC. The protocols for some of the functionality of Active Directory domain controllers has been partially
591implemented on an experimental only basis. Please do not expect Samba-3 to support these protocols. Do not
592depend on any such functionality either now or in the future. The Samba Team may remove these experimental
593features or may change their behavior. This is mentioned for the benefit of those who have discovered secret
594capabilities in Samba-3 and who have asked when this functionality will be completed. The answer is maybe
595someday or maybe never!
596</p><p>
597<a class="indexterm" name="id330454"></a>
598<a class="indexterm" name="id330460"></a>
599To be sure, Samba-3 is designed to provide most of the functionality that Microsoft Windows NT4-style
600domain controllers have. Samba-3 does not have all the capabilities of Windows NT4, but it does have
601a number of features that Windows NT4 domain controllers do not have. In short, Samba-3 is not NT4 and it
602is not Windows Server 200x: it is not an Active Directory server. We hope this is plain and simple
603enough for all to understand.
604</p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id330473"></a>Domain and Network Logon Configuration</h2></div></div></div><p>
605<a class="indexterm" name="id330481"></a>
606The subject of network or domain logons is discussed here because it forms
607an integral part of the essential functionality that is provided by a domain controller.
608</p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id330490"></a>Domain Network Logon Service</h3></div></div></div><p>
609<a class="indexterm" name="id330498"></a>
610All domain controllers must run the netlogon service (<span class="emphasis"><em>domain logons</em></span>
611in Samba). One domain controller must be configured with <a class="indexterm" name="id330510"></a>domain master = Yes
612(the PDC); on all BDCs set the parameter <a class="indexterm" name="id330517"></a>domain master = No.
613</p><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id330525"></a>Example Configuration</h4></div></div></div><div class="example"><a name="PDC-config"></a><p class="title"><b>Example 4.2. smb.conf for being a PDC</b></p><div class="example-contents"><table class="simplelist" border="0" summary="Simple list"><tr><td> </td></tr><tr><td><em class="parameter"><code>[global]</code></em></td></tr><tr><td><a class="indexterm" name="id330554"></a><em class="parameter"><code>domain logons = Yes</code></em></td></tr><tr><td><a class="indexterm" name="id330567"></a><em class="parameter"><code>domain master = (Yes on PDC, No on BDCs)</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[netlogon]</code></em></td></tr><tr><td><a class="indexterm" name="id330588"></a><em class="parameter"><code>comment = Network Logon Service</code></em></td></tr><tr><td><a class="indexterm" name="id330601"></a><em class="parameter"><code>path = /var/lib/samba/netlogon</code></em></td></tr><tr><td><a class="indexterm" name="id330614"></a><em class="parameter"><code>guest ok = Yes</code></em></td></tr><tr><td><a class="indexterm" name="id330626"></a><em class="parameter"><code>browseable = No</code></em></td></tr></table></div></div><br class="example-break"></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id330641"></a>The Special Case of MS Windows XP Home Edition</h4></div></div></div><p>
614<a class="indexterm" name="id330649"></a>
615To be completely clear: If you want MS Windows XP Home Edition to integrate with your
616MS Windows NT4 or Active Directory domain security, understand it cannot be done.
617The only option is to purchase the upgrade from MS Windows XP Home Edition to
618MS Windows XP Professional.
619</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
620MS Windows XP Home Edition does not have the ability to join any type of domain
621security facility. Unlike MS Windows 9x/Me, MS Windows XP Home Edition also completely
622lacks the ability to log onto a network.
623</p></div><p>
624Now that this has been said, please do not ask the mailing list or email any of the
625Samba Team members with your questions asking how to make this work. It can't be done.
626If it can be done, then to do so would violate your software license agreement with
627Microsoft, and we recommend that you do not do that.
628</p></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id330672"></a>The Special Case of Windows 9x/Me</h4></div></div></div><p>
629<a class="indexterm" name="id330680"></a>
630<a class="indexterm" name="id330687"></a>
631<a class="indexterm" name="id330694"></a>
632<a class="indexterm" name="id330700"></a>
633<a class="indexterm" name="id330707"></a>
634A domain and a workgroup are exactly the same in terms of network
635browsing. The difference is that a distributable authentication
636database is associated with a domain, for secure login access to a
637network. Also, different access rights can be granted to users if they
638successfully authenticate against a domain logon server. Samba-3 does this
639now in the same way as MS Windows NT/200x.
640</p><p>
641<a class="indexterm" name="id330721"></a>
642The SMB client logging on to a domain has an expectation that every other
643server in the domain should accept the same authentication information.
644Network browsing functionality of domains and workgroups is identical and
645is explained in this documentation under the browsing discussions.
646It should be noted that browsing is totally orthogonal to logon support.
647</p><p>
648<a class="indexterm" name="id330737"></a>
649<a class="indexterm" name="id330744"></a>
650<a class="indexterm" name="id330750"></a>
651Issues related to the single-logon network model are discussed in this
652section. Samba supports domain logons, network logon scripts, and user
653profiles for MS Windows for Workgroups and MS Windows 9x/Me clients,
654which are the focus of this section.
655</p><p>
656<a class="indexterm" name="id330763"></a>
657When an SMB client in a domain wishes to log on, it broadcasts requests for a logon server. The first one to
658reply gets the job and validates its password using whatever mechanism the Samba administrator has installed.
659It is possible (but ill advised) to create a domain where the user database is not shared between servers;
660that is, they are effectively workgroup servers advertising themselves as participating in a domain. This
661demonstrates how authentication is quite different from but closely involved with domains.
662</p><p>
663Using these features, you can make your clients verify their logon via
664the Samba server, make clients run a batch file when they log on to
665the network and download their preferences, desktop, and start menu.
666</p><p><span class="emphasis"><em>
667MS Windows XP Home edition is not able to join a domain and does not permit the use of domain logons.
668</em></span></p><p>
669Before launching into the configuration instructions, it is worthwhile to look at how a Windows 9x/Me client
670performs a logon:
671</p><div class="orderedlist"><ol type="1"><li><p>
672 <a class="indexterm" name="id330801"></a>
673 <a class="indexterm" name="id330807"></a>
674 The client broadcasts (to the IP broadcast address of the subnet it is in)
675 a NetLogon request. This is sent to the NetBIOS name DOMAIN&lt;1C&gt; at the
676 NetBIOS layer. The client chooses the first response it receives, which
677 contains the NetBIOS name of the logon server to use in the format of
678 <code class="filename">\\SERVER</code>. The <code class="literal">1C</code> name is the name
679 type that is registered by domain controllers (SMB/CIFS servers that provide
680 the netlogon service).
681 </p></li><li><p>
682 <a class="indexterm" name="id330841"></a>
683 <a class="indexterm" name="id330847"></a>
684 <a class="indexterm" name="id330854"></a>
685 The client connects to that server, logs on (does an SMBsessetupX) and
686 then connects to the IPC$ share (using an SMBtconX).
687 </p></li><li><p>
688 <a class="indexterm" name="id330869"></a>
689 The client does a NetWkstaUserLogon request, which retrieves the name
690 of the user's logon script.
691 </p></li><li><p>
692 The client then connects to the NetLogon share and searches for said script.
693 If it is found and can be read, it is retrieved and executed by the client.
694 After this, the client disconnects from the NetLogon share.
695 </p></li><li><p>
696 <a class="indexterm" name="id330891"></a>
697 <a class="indexterm" name="id330898"></a>
698 The client sends a NetUserGetInfo request to the server to retrieve
699 the user's home share, which is used to search for profiles. Since the
700 response to the NetUserGetInfo request does not contain much more than
701 the user's home share, profiles for Windows 9x clients must reside in the user
702 home directory.
703 </p></li><li><p>
704 <a class="indexterm" name="id330914"></a>
705 The client connects to the user's home share and searches for the
706 user's profile. As it turns out, you can specify the user's home share as
707 a share name and path. For example, <code class="filename">\\server\fred\.winprofile</code>.
708 If the profiles are found, they are implemented.
709 </p></li><li><p>
710 <a class="indexterm" name="id330935"></a>
711 The client then disconnects from the user's home share and reconnects to
712 the NetLogon share and looks for <code class="filename">CONFIG.POL</code>, the policies file. If this is
713 found, it is read and implemented.
714 </p></li></ol></div><p>
715The main difference between a PDC and a Windows 9x/Me logon server configuration is:
716</p><div class="itemizedlist"><ul type="disc"><li><p>
717 <a class="indexterm" name="id330962"></a>
718 <a class="indexterm" name="id330971"></a>
719 Password encryption is not required for a Windows 9x/Me logon server. But note
720 that beginning with MS Windows 98 the default setting is that plaintext
721 password support is disabled. It can be re-enabled with the registry
722 changes that are documented in <a href="PolicyMgmt.html" title="Chapter 26. System and Account Policies">System and Account Policies</a>.
723 </p></li><li><p>
724 <a class="indexterm" name="id330992"></a>
725 Windows 9x/Me clients do not require and do not use Machine Trust Accounts.
726 </p></li></ul></div><p>
727<a class="indexterm" name="id331003"></a>
728A Samba PDC will act as a Windows 9x/Me logon server; after all, it does provide the
729network logon services that MS Windows 9x/Me expect to find.
730</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
731<a class="indexterm" name="id331016"></a>
732Use of plaintext passwords is strongly discouraged. Where used they are easily detected
733using a sniffer tool to examine network traffic.
734</p></div></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id331027"></a>Security Mode and Master Browsers</h3></div></div></div><p>
735<a class="indexterm" name="id331035"></a>
736<a class="indexterm" name="id331042"></a>
737<a class="indexterm" name="id331048"></a>
738There are a few comments to make in order to tie up some loose ends. There has been much debate over the issue
739of whether it is okay to configure Samba as a domain controller that operates with security mode other than
740user-mode. The only security mode that will not work due to technical reasons is share-mode security. Domain
741and server mode security are really just a variation on SMB user-level security.
742</p><p>
743<a class="indexterm" name="id331062"></a>
744<a class="indexterm" name="id331069"></a>
745<a class="indexterm" name="id331076"></a>
746<a class="indexterm" name="id331082"></a>
747<a class="indexterm" name="id331089"></a>
748<a class="indexterm" name="id331095"></a>
749<a class="indexterm" name="id331102"></a>
750Actually, this issue is also closely tied to the debate on whether Samba must be the DMB for its workgroup
751when operating as a domain controller. In a pure Microsoft Windows NT domain, the PDC wins the election to be
752the DMB, and then registers the DOMAIN&lt;1B&gt; NetBIOS name. This is not the name used by Windows clients
753to locate the domain controller, all domain controllers register the DOMAIN&lt;1C&gt; name and Windows clients
754locate a network logon server by seraching for the DOMAIN&lt;1C&gt; name. A DMB is a Domain Master Browser
755 see <a href="NetworkBrowsing.html" title="Chapter 10. Network Browsing">The Network Browsing Chapter</a>, <a href="NetworkBrowsing.html#DMB" title="Configuring Workgroup Browsing">Configuring WORKGROUP Browsing</a>; Microsoft PDCs expect to win the election to become the
756DMB, if it loses that election it will report a continuous and rapid sequence of warning messages to its
757Windows event logger complaining that it has lost the election to become a DMB. For this reason, in networks
758where a Samba server is the PDC it is wise to configure the Samba domain controller as the DMB.
759</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
760<a class="indexterm" name="id331143"></a>
761<a class="indexterm" name="id331149"></a>
762<a class="indexterm" name="id331156"></a>
763<a class="indexterm" name="id331163"></a>
764<a class="indexterm" name="id331170"></a>
765SMB/CIFS servers that register the DOMAIN&lt;1C&gt; name do so because they provide the network logon
766service. Server that register the DOMAIN&lt;1B&gt; name are DMBs meaning that they are responsible
767for browse list synchronization across all machines that have registered the DOMAIN&lt;1D&gt; name. The later
768are LMBs that have the responsibility to listen to all NetBIOS name registrations that occur locally to their
769own network segment. The network logon service (NETLOGON) is germane to domain control and has nothing to do
770with network browsing and browse list management. The 1C and 1B/1D name services are orthogonal to each
771other.
772</p></div><p>
773Now back to the issue of configuring a Samba domain controller to use a mode other than <a class="indexterm" name="id331201"></a>security = user. If a Samba host is configured to use another SMB server or domain
774controller in order to validate user connection requests, it is a fact that some other machine on the network
775(the <a class="indexterm" name="id331209"></a>password server) knows more about the user than the Samba host. About 99 percent
776of the time, this other host is a domain controller. Now to operate in domain mode security, the
777<a class="indexterm" name="id331218"></a>workgroup parameter must be set to the name of the Windows NT domain (which already
778has a domain controller). If the domain does not already have a domain controller, you do not yet have a
779domain.
780</p><p>
781Configuring a Samba box as a domain controller for a domain that already by definition has a
782PDC is asking for trouble. Therefore, you should always configure the Samba domain controller
783to be the DMB for its domain and set <a class="indexterm" name="id331231"></a>security = user.
784This is the only officially supported mode of operation.
785</p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id331242"></a>Common Errors</h2></div></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id331248"></a>&#8220;<span class="quote">$</span>&#8221; Cannot Be Included in Machine Name</h3></div></div></div><p>
786<a class="indexterm" name="id331258"></a>
787<a class="indexterm" name="id331264"></a>
788<a class="indexterm" name="id331271"></a>
789A machine account, typically stored in <code class="filename">/etc/passwd</code>, takes the form of the machine
790name with a &#8220;<span class="quote">$</span>&#8221; appended. Some BSD systems will not create a user with a &#8220;<span class="quote">$</span>&#8221; in the name.
791Recent versions of FreeBSD have removed this limitation, but older releases are still in common use.
792</p><p>
793<a class="indexterm" name="id331296"></a>
794The problem is only in the program used to make the entry. Once made, it works perfectly. Create a user
795without the &#8220;<span class="quote">$</span>&#8221;. Then use <code class="literal">vipw</code> to edit the entry, adding the &#8220;<span class="quote">$</span>&#8221;.
796Or create the whole entry with vipw if you like; make sure you use a unique user login ID.
797</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>The machine account must have the exact name that the workstation has.</p></div><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
798The UNIX tool <code class="literal">vipw</code> is a common tool for directly editing the <code class="filename">/etc/passwd</code> file.
799The use of vipw will ensure that shadow files (where used) will remain current with the passwd file. This is
800important for security reasons.
801</p></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id331343"></a>Joining Domain Fails Because of Existing Machine Account</h3></div></div></div><p>
802<a class="indexterm" name="id331351"></a>
803&#8220;<span class="quote">I get told, `You already have a connection to the Domain....' or `Cannot join domain, the
804credentials supplied conflict with an existing set...' when creating a Machine Trust Account.</span>&#8221;
805</p><p>
806This happens if you try to create a Machine Trust Account from the machine itself and already have a
807connection (e.g., mapped drive) to a share (or IPC$) on the Samba PDC. The following command will remove all
808network drive connections:
809</p><pre class="screen">
810<code class="prompt">C:\&gt; </code><strong class="userinput"><code>net use * /d</code></strong>
811</pre><p>
812This will break all network connections.
813</p><p>
814Further, if the machine is already a &#8220;<span class="quote">member of a workgroup</span>&#8221; that is the same name as the domain
815you are joining (bad idea), you will get this message. Change the workgroup name to something else
816it does not matter what reboot, and try again.
817</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id331401"></a>The System Cannot Log You On (C000019B)</h3></div></div></div><p>&#8220;<span class="quote">
818I joined the domain successfully but after upgrading to a newer version of the Samba code I get the message,
819<span class="errorname">`The system cannot log you on (C000019B). Please try again or consult your system
820administrator</span> when attempting to logon.'</span>&#8221;
821</p><p>
822<a class="indexterm" name="id331419"></a>
823This occurs when the domain SID stored in the secrets.tdb database is changed. The most common cause of a
824change in domain SID is when the domain name and/or the server name (NetBIOS name) is changed. The only way
825to correct the problem is to restore the original domain SID or remove the domain client from the domain and
826rejoin. The domain SID may be reset using either the net or rpcclient utilities.
827</p><p>
828To reset or change the domain SID you can use the net command as follows:
829
830</p><pre class="screen">
831<code class="prompt">root# </code><strong class="userinput"><code>net getlocalsid 'OLDNAME'</code></strong>
832<code class="prompt">root# </code><strong class="userinput"><code>net setlocalsid 'SID'</code></strong>
833</pre><p>
834</p><p>
835Workstation Machine Trust Accounts work only with the domain (or network) SID. If this SID changes,
836domain members (workstations) will not be able to log onto the domain. The original domain SID
837can be recovered from the secrets.tdb file. The alternative is to visit each workstation to rejoin
838it to the domain.
839</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id331468"></a>The Machine Trust Account Is Not Accessible</h3></div></div></div><p>
840&#8220;<span class="quote">When I try to join the domain I get the message, <span class="errorname">"The machine account
841for this computer either does not exist or is not accessible</span>." What's wrong?</span>&#8221;
842</p><p>
843This problem is caused by the PDC not having a suitable Machine Trust Account. If you are using the
844<a class="indexterm" name="id331488"></a>add machine script method to create accounts, then this would indicate that it has not
845worked. Ensure the domain admin user system is working.
846</p><p>
847Alternately, if you are creating account entries manually, then they have not been created correctly. Make
848sure that you have the entry correct for the Machine Trust Account in <code class="filename">smbpasswd</code> file on
849the Samba PDC. If you added the account using an editor rather than using the smbpasswd utility, make sure
850that the account name is the machine NetBIOS name with a &#8220;<span class="quote">$</span>&#8221; appended to it (i.e.,
851computer_name$). There must be an entry in both the POSIX UNIX system account backend as well as in the
852SambaSAMAccount backend. The default backend for Samba-3 (i.e., the parameter <em class="parameter"><code>passdb
853backend</code></em> is not specified in the <code class="filename">smb.conf</code> file, or if specified is set to
854<code class="literal">smbpasswd</code>, are respectively the <code class="filename">/etc/passwd</code> and
855<code class="filename">/etc/samba/smbpasswd</code> (or <code class="filename">/usr/local/samba/lib/private/smbpasswd</code> if
856compiled using Samba Team default settings). The use of the <code class="filename">/etc/passwd</code> can be overridden
857by alternative settings in the NSS <code class="filename">/etc/nsswitch.conf</code> file.
858</p><p>
859Some people have also reported that inconsistent subnet masks between the Samba server and the NT
860client can cause this problem. Make sure that these are consistent for both client and server.
861</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id331569"></a>Account Disabled</h3></div></div></div><p>&#8220;<span class="quote">When I attempt to log in to a Samba domain from a NT4/W200x workstation,
862I get a message about my account being disabled.</span>&#8221;</p><p>
863Enable the user accounts with <strong class="userinput"><code>smbpasswd -e <em class="replaceable"><code>username</code></em>
864</code></strong>. This is normally done as an account is created.
865</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id331595"></a>Domain Controller Unavailable</h3></div></div></div><p>&#8220;<span class="quote">Until a few minutes after Samba has started, clients get the error `Domain Controller Unavailable'</span>&#8221;</p><p>
866A domain controller has to announce its role on the network. This usually takes a while. Be patient for up to 15 minutes,
867then try again.
868</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id331611"></a>Cannot Log onto Domain Member Workstation After Joining Domain</h3></div></div></div><p>
869<a class="indexterm" name="id331619"></a>
870<a class="indexterm" name="id331626"></a>
871After successfully joining the domain, user logons fail with one of two messages: one to the
872effect that the domain controller cannot be found; the other claims that the account does not
873exist in the domain or that the password is incorrect. This may be due to incompatible
874settings between the Windows client and the Samba-3 server for <span class="emphasis"><em>schannel</em></span>
875(secure channel) settings or <span class="emphasis"><em>smb signing</em></span> settings. Check your Samba
876settings for <span class="emphasis"><em>client schannel</em></span>, <span class="emphasis"><em>server schannel</em></span>,
877<span class="emphasis"><em>client signing</em></span>, <span class="emphasis"><em>server signing</em></span> by executing:
878</p><pre class="screen">
879<code class="literal">testparm -v | grep channel</code> and looking for the value of these parameters.
880</pre><p>
881</p><p>
882Also use the MMC Local Security Settings. This tool is available from the
883Control Panel. The Policy settings are found in the Local Policies/Security Options area and are prefixed by
884<span class="emphasis"><em>Secure Channel:..., and Digitally sign...</em></span>.
885</p><p>
886It is important that these be set consistently with the Samba-3 server settings.
887</p></div></div><div class="footnotes"><br><hr width="100" align="left"><div class="footnote"><p><sup>[<a name="ftn.id328934" href="#id328934">1</a>] </sup>See also <a href="passdb.html" title="Chapter 11. Account Information Databases">Account Information
888Databases</a>.</p>.</div><div class="footnote"><p><sup>[<a name="ftn.id329384" href="#id329384">2</a>] </sup>See <a href="NetworkBrowsing.html" title="Chapter 10. Network Browsing">Network Browsing</a>, and
889 <a href="integrate-ms-networks.html" title="Chapter 29. Integrating MS Windows Networks with Samba">Integrating MS Windows Networks with Samba</a>.</p></div><div class="footnote"><p><sup>[<a name="ftn.id329659" href="#id329659">3</a>] </sup>See <a href="NetworkBrowsing.html" title="Chapter 10. Network Browsing">Network
890Browsing</a>.</p></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ServerType.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 3. Server Types and Security Modes </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 5. Backup Domain Control</td></tr></table></div></body></html>
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