1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Chapter�6.�Domain Membership</title><link rel="stylesheet" href="samba.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.66.1"><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="samba-bdc.html" title="Chapter�5.�Backup Domain Control"><link rel="next" href="StandAloneServer.html" title="Chapter�7.�Stand-alone Servers"></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�6.�Domain Membership</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="samba-bdc.html">Prev</a>�</td><th width="60%" align="center">Part�II.�Server Configuration Basics</th><td width="20%" align="right">�<a accesskey="n" href="StandAloneServer.html">Next</a></td></tr></table><hr></div><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="domain-member"></a>Chapter�6.�Domain Membership</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><tt class="email"><<a href="mailto:jht@samba.org">jht@samba.org</a>></tt></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">Jeremy</span> <span class="surname">Allison</span></h3><div class="affiliation"><span class="orgname">Samba Team<br></span><div class="address"><p><tt class="email"><<a href="mailto:jra@samba.org">jra@samba.org</a>></tt></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><tt class="email"><<a href="mailto:jerry@samba.org">jerry@samba.org</a>></tt></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">Andrew</span> <span class="surname">Tridgell</span></h3><div class="affiliation"><span class="orgname">Samba Team<br></span><div class="address"><p><tt class="email"><<a href="mailto:tridge@samba.org">tridge@samba.org</a>></tt></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">Jelmer</span> <span class="othername">R.</span> <span class="surname">Vernooij</span></h3><div class="affiliation"><span class="orgname">The Samba Team<br></span><div class="address"><p><tt class="email"><<a href="mailto:jelmer@samba.org">jelmer@samba.org</a>></tt></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><tt class="email"><<a href="mailto:gd@suse.de">gd@suse.de</a>></tt></p></div></div></div></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="sect1"><a href="domain-member.html#id2540758">Features and Benefits</a></span></dt><dt><span class="sect1"><a href="domain-member.html#machine-trust-accounts">MS Windows Workstation/Server Machine Trust Accounts</a></span></dt><dd><dl><dt><span class="sect2"><a href="domain-member.html#id2541051">Manual Creation of Machine Trust Accounts</a></span></dt><dt><span class="sect2"><a href="domain-member.html#id2541332">Managing Domain Machine Accounts using NT4 Server Manager</a></span></dt><dt><span class="sect2"><a href="domain-member.html#id2541553">On-the-Fly Creation of Machine Trust Accounts</a></span></dt><dt><span class="sect2"><a href="domain-member.html#id2541625">Making an MS Windows Workstation or Server a Domain Member</a></span></dt></dl></dd><dt><span class="sect1"><a href="domain-member.html#domain-member-server">Domain Member Server</a></span></dt><dd><dl><dt><span class="sect2"><a href="domain-member.html#id2541812">Joining an NT4-type Domain with Samba-3</a></span></dt><dt><span class="sect2"><a href="domain-member.html#id2542255">Why Is This Better Than <i class="parameter"><tt>security = server</tt></i>?</a></span></dt></dl></dd><dt><span class="sect1"><a href="domain-member.html#ads-member">Samba ADS Domain Membership</a></span></dt><dd><dl><dt><span class="sect2"><a href="domain-member.html#id2542416">Configure <tt class="filename">smb.conf</tt></a></span></dt><dt><span class="sect2"><a href="domain-member.html#id2542561">Configure <tt class="filename">/etc/krb5.conf</tt></a></span></dt><dt><span class="sect2"><a href="domain-member.html#ads-create-machine-account">Create the Computer Account</a></span></dt><dt><span class="sect2"><a href="domain-member.html#ads-test-server">Testing Server Setup</a></span></dt><dt><span class="sect2"><a href="domain-member.html#ads-test-smbclient">Testing with <span class="application">smbclient</span></a></span></dt><dt><span class="sect2"><a href="domain-member.html#id2543078">Notes</a></span></dt></dl></dd><dt><span class="sect1"><a href="domain-member.html#id2543108">Sharing User ID Mappings between Samba Domain Members</a></span></dt><dt><span class="sect1"><a href="domain-member.html#id2543219">Common Errors</a></span></dt><dd><dl><dt><span class="sect2"><a href="domain-member.html#id2543247">Cannot Add Machine Back to Domain</a></span></dt><dt><span class="sect2"><a href="domain-member.html#id2543278">Adding Machine to Domain Fails</a></span></dt><dt><span class="sect2"><a href="domain-member.html#id2543403">I Can't Join a Windows 2003 PDC</a></span></dt></dl></dd></dl></div><p> 2Domain Membership is a subject of vital concern. Samba must be able to 3participate as a member server in a Microsoft Domain Security context, and 4Samba must be capable of providing Domain machine member trust accounts, 5otherwise it would not be able to offer a viable option for many users. 6</p><p> 7This chapter covers background information pertaining to Domain Membership, 8the Samba configuration for it, and MS Windows client procedures for joining a 9domain. Why is this necessary? Because both are areas in which there exists 10within the current MS Windows networking world and particularly in the 11UNIX/Linux networking and administration world, a considerable level of 12misinformation, incorrect understanding and a lack of knowledge. Hopefully 13this chapter will fill the voids. 14</p><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2540758"></a>Features and Benefits</h2></div></div></div><p> 15MS Windows workstations and servers that want to participate in Domain Security need to 16be made Domain Members. Participating in Domain Security is often called 17<span class="emphasis"><em>Single Sign On</em></span> or <span class="acronym">SSO</span> for short. This 18chapter describes the process that must be followed to make a workstation 19(or another server be it an <span class="application">MS Windows NT4 / 200x</span> 20server) or a Samba server a member of an MS Windows Domain Security context. 21</p><p> 22<a class="indexterm" name="id2540792"></a> 23Samba-3 can join an MS Windows NT4-style domain as a native member server, an 24MS Windows Active Directory Domain as a native member server, or a Samba Domain 25Control network. Domain Membership has many advantages: 26</p><div class="itemizedlist"><ul type="disc"><li><p> 27<a class="indexterm" name="id2540811"></a> 28 MS Windows workstation users get the benefit of SSO. 29 </p></li><li><p> 30 Domain user access rights and file ownership/access controls can be set 31 from the single Domain Security Account Manager (SAM) database 32 (works with Domain Member servers as well as with MS Windows workstations 33 that are Domain Members). 34 </p></li><li><p> 35 Only <span class="application">MS Windows NT4/200x/XP Professional</span> 36 workstations that are Domain Members can use network logon facilities. 37 </p></li><li><p> 38 Domain Member workstations can be better controlled through the use of 39 Policy files (<tt class="filename">NTConfig.POL</tt>) and Desktop Profiles. 40 </p></li><li><p> 41 Through the use of logon scripts, users can be given transparent access to network 42 applications that run off application servers. 43 </p></li><li><p> 44 Network administrators gain better application and user access management 45 abilities because there is no need to maintain user accounts on any network 46 client or server, other than the central Domain database 47 (either NT4/Samba SAM style Domain, NT4 Domain that is backend-ed with an 48 LDAP directory, or via an Active Directory infrastructure). 49 </p></li></ul></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="machine-trust-accounts"></a>MS Windows Workstation/Server Machine Trust Accounts</h2></div></div></div><p> 50<a class="indexterm" name="id2540885"></a> 51A Machine Trust Account is an account that is used to authenticate a client 52machine (rather than a user) to the Domain Controller server. In Windows terminology, 53this is known as a “<span class="quote"><span class="emphasis"><em>Computer Account.</em></span></span>” The purpose of the machine account 54is to prevent a rogue user and Domain Controller from colluding to gain access to a 55domain member workstation. 56</p><p> 57The password of a Machine Trust Account acts as the shared secret for 58secure communication with the Domain Controller. This is a security 59feature to prevent an unauthorized machine with the same NetBIOS name 60from joining the domain and gaining access to domain user/group 61accounts. Windows NT/200x/XP Professional clients use machine trust 62accounts, but Windows 9x/Me/XP Home clients do not. Hence, a 63Windows 9x/Me/XP Home client is never a true member of a Domain 64because it does not possess a Machine Trust Account, and, thus, has no 65shared secret with the Domain Controller. 66</p><p> 67A Windows NT4 PDC stores each Machine Trust Account in the Windows Registry. 68The introduction of MS Windows 2000 saw the introduction of Active Directory, 69the new repository for Machine Trust Accounts. A Samba PDC, however, stores 70each Machine Trust Account in two parts, 71as follows: 72 73</p><div class="itemizedlist"><ul type="disc"><li><p> 74 A Domain Security Account (stored in the 75 <a class="indexterm" name="id2540939"></a>passdb backend that has been configured in the 76 <tt class="filename">smb.conf</tt> file. The precise nature of the account information that is 77 stored depends on the type of backend database that has been chosen. 78 </p><p> 79 The older format of this data is the <tt class="filename">smbpasswd</tt> database 80 that contains the UNIX login ID, the UNIX user identifier (UID), and the 81 LanMan and NT encrypted passwords. There is also some other information in 82 this file that we do not need to concern ourselves with here. 83 </p><p> 84 The two newer database types are called ldapsam, and 85 tdbsam. Both store considerably more data than the 86 older <tt class="filename">smbpasswd</tt> file did. The extra information 87 enables new user account controls to be implemented. 88 </p></li><li><p> 89 A corresponding UNIX account, typically stored in 90 <tt class="filename">/etc/passwd</tt>. Work is in progress to allow a 91 simplified mode of operation that does not require UNIX user accounts, but 92 this may not be a feature of the early releases of Samba-3. 93 </p></li></ul></div><p> 94</p><p> 95<a class="indexterm" name="id2541000"></a> 96There are three ways to create Machine Trust Accounts: 97</p><div class="itemizedlist"><ul type="disc"><li><p> 98 Manual creation from the UNIX/Linux command line. Here, both the Samba and 99 corresponding UNIX account are created by hand. 100 </p></li><li><p> 101 <a class="indexterm" name="id2541024"></a> 102 Using the MS Windows NT4 Server Manager, either from an NT4 Domain Member 103 server, or using the Nexus toolkit available from the Microsoft Web site. 104 This tool can be run from any MS Windows machine as long as the user is 105 logged on as the administrator account. 106 </p></li><li><p> 107 “<span class="quote"><span class="emphasis"><em>On-the-fly</em></span></span>” creation. The Samba Machine Trust Account is automatically 108 created by Samba at the time the client is joined to the domain. 109 (For security, this is the recommended method.) The corresponding UNIX 110 account may be created automatically or manually. 111 </p></li></ul></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2541051"></a>Manual Creation of Machine Trust Accounts</h3></div></div></div><p> 112The first step in manually creating a Machine Trust Account is to manually 113create the corresponding UNIX account in <tt class="filename">/etc/passwd</tt>. 114This can be done using <span><b class="command">vipw</b></span> or another “<span class="quote"><span class="emphasis"><em>add user</em></span></span>” command 115that is normally used to create new UNIX accounts. The following is an example for 116a Linux-based Samba server: 117</p><p> 118<a class="indexterm" name="id2541083"></a> 119<a class="indexterm" name="id2541090"></a> 120</p><pre class="screen"> 121<tt class="prompt">root# </tt><b class="userinput"><tt>/usr/sbin/useradd -g machines -d /var/lib/nobody -c <i class="replaceable"><tt>"machine nickname"</tt></i> \ 122 -s /bin/false <i class="replaceable"><tt>machine_name</tt></i>$ </tt></b> 123 124<tt class="prompt">root# </tt><b class="userinput"><tt>passwd -l <i class="replaceable"><tt>machine_name</tt></i>$</tt></b> 125</pre><p> 126</p><p>In the example above there is an existing system group “<span class="quote"><span class="emphasis"><em>machines</em></span></span>” which is used 127as the primary group for all machine accounts. In the following examples the “<span class="quote"><span class="emphasis"><em>machines</em></span></span>” group has 128numeric GID equal 100.</p><p> 129<a class="indexterm" name="id2541154"></a> 130On *BSD systems, this can be done using the <span><b class="command">chpass</b></span> utility: 131</p><p> 132</p><pre class="screen"> 133<tt class="prompt">root# </tt><b class="userinput"><tt>chpass -a \ 134'<i class="replaceable"><tt>machine_name</tt></i>$:*:101:100::0:0:Windows <i class="replaceable"><tt>machine_name</tt></i>:/dev/null:/sbin/nologin'</tt></b> 135</pre><p> 136</p><p> 137The <tt class="filename">/etc/passwd</tt> entry will list the machine name 138with a “<span class="quote"><span class="emphasis"><em>$</em></span></span>” appended, will not have a password, will have a null shell and no 139home directory. For example, a machine named “<span class="quote"><span class="emphasis"><em>doppy</em></span></span>” would have an 140<tt class="filename">/etc/passwd</tt> entry like this: 141</p><pre class="programlisting"> 142doppy$:x:505:100:<i class="replaceable"><tt>machine_nickname</tt></i>:/dev/null:/bin/false 143</pre><p> 144Above, <i class="replaceable"><tt>machine_nickname</tt></i> can be any 145descriptive name for the client, i.e., BasementComputer. 146<i class="replaceable"><tt>machine_name</tt></i> absolutely must be the NetBIOS 147name of the client to be joined to the domain. The “<span class="quote"><span class="emphasis"><em>$</em></span></span>” must be 148appended to the NetBIOS name of the client or Samba will not recognize 149this as a Machine Trust Account. 150</p><p> 151Now that the corresponding UNIX account has been created, the next step is to create 152the Samba account for the client containing the well-known initial 153Machine Trust Account password. This can be done using the 154<span><b class="command">smbpasswd</b></span> command 155as shown here: 156</p><p> 157</p><pre class="screen"> 158<tt class="prompt">root# </tt><b class="userinput"><tt>smbpasswd -a -m <i class="replaceable"><tt>machine_name</tt></i></tt></b> 159</pre><p> 160</p><p> 161where <i class="replaceable"><tt>machine_name</tt></i> is the machine's NetBIOS 162name. The RID of the new machine account is generated from the UID of 163the corresponding UNIX account. 164</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> 165Manually creating a Machine Trust Account using this method is the 166equivalent of creating a Machine Trust Account on a Windows NT PDC using 167<a class="indexterm" name="id2541309"></a> 168the <span class="application">Server Manager</span>. From the time at which the 169account is created to the time the client joins the domain and 170changes the password, your domain is vulnerable to an intruder joining 171your domain using a machine with the same NetBIOS name. A PDC inherently 172trusts members of the domain and will serve out a large degree of user 173information to such clients. You have been warned! 174</p></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2541332"></a>Managing Domain Machine Accounts using NT4 Server Manager</h3></div></div></div><p> 175A working <a class="indexterm" name="id2541340"></a>add machine script is essential 176for machine trust accounts to be automatically created. This applies no matter whether 177one uses automatic account creation, or if one wishes to use the NT4 Domain Server Manager. 178</p><p> 179<a class="indexterm" name="id2541354"></a> 180If the machine from which you are trying to manage the domain is an 181<span class="application">MS Windows NT4 workstation or MS Windows 200x/XP Professional</span>, 182the tool of choice is the package called <span><b class="command">SRVTOOLS.EXE</b></span>. 183When executed in the target directory it will unpack <span><b class="command">SrvMgr.exe</b></span> 184and <span><b class="command">UsrMgr.exe</b></span> (both are domain management tools for MS Windows NT4 workstation). 185</p><p> 186<a class="indexterm" name="id2541393"></a> 187If your workstation is a <span class="application">Microsoft Windows 9x/Me</span> family product 188 you should download the <span><b class="command">Nexus.exe</b></span> package from the Microsoft web site. 189When executed from the target directory this will unpack the same tools but for use on 190this platform. 191</p><p> 192Further information about these tools may be obtained from the following locations: 193</p><p> 194</p><table class="simplelist" border="0" summary="Simple list"><tr><td><a href="http://support.microsoft.com/default.aspx?scid=kb;en-us;173673" target="_top">http://support.microsoft.com/default.aspx?scid=kb;en-us;173673</a></td></tr><tr><td><a href="http://support.microsoft.com/default.aspx?scid=kb;en-us;172540" target="_top">http://support.microsoft.com/default.aspx?scid=kb;en-us;172540</a></td></tr></table><p> 195</p><p> 196Launch the <span><b class="command">srvmgr.exe</b></span> (Server Manager for Domains) and follow these steps: 197</p><div class="procedure"><a name="id2541453"></a><p class="title"><b>Procedure�6.1.�Server Manager Account Machine Account Management</b></p><ol type="1"><li><p> 198 From the menu select <span class="guimenu">Computer</span>. 199 </p></li><li><p> 200 Click <span class="guimenuitem">Select Domain</span>. 201 </p></li><li><p> 202 Click the name of the domain you wish to administer in the 203 <span class="guilabel">Select Domain</span> panel and then click 204 <span class="guibutton">OK</span>. 205 </p></li><li><p> 206 Again from the menu select <span class="guimenu">Computer</span>. 207 </p></li><li><p> 208 Select <span class="guimenuitem">Add to Domain</span>. 209 </p></li><li><p> 210 In the dialog box, click the radio button to 211 <span class="guilabel">Add NT Workstation of Server</span>, then 212 enter the machine name in the field provided, and click the 213 <span class="guibutton">Add</span> button. 214 </p></li></ol></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2541553"></a>On-the-Fly Creation of Machine Trust Accounts</h3></div></div></div><p> 215The second (and recommended) way of creating Machine Trust Accounts is 216simply to allow the Samba server to create them as needed when the client 217is joined to the domain. 218</p><p>Since each Samba Machine Trust Account requires a corresponding UNIX account, a method 219for automatically creating the UNIX account is usually supplied; this requires configuration of the 220add machine script option in <tt class="filename">smb.conf</tt>. This method is not required, however, corresponding UNIX 221accounts may also be created manually. 222</p><p> 223Here is an example for a Red Hat Linux system. 224</p><table class="simplelist" border="0" summary="Simple list"><tr><td> </td></tr><tr><td><i class="parameter"><tt>[global]</tt></i></td></tr><tr><td># <...remainder of parameters...></td></tr><tr><td><a class="indexterm" name="id2541607"></a><i class="parameter"><tt> 225 226 add machine script = /usr/sbin/useradd -d /var/lib/nobody -g 100 -s /bin/false -M %u</tt></i></td></tr></table></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2541625"></a>Making an MS Windows Workstation or Server a Domain Member</h3></div></div></div><p> 227The procedure for making an MS Windows workstation or server a member of the domain varies 228with the version of Windows. 229</p><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2541635"></a>Windows 200x/XP Professional Client</h4></div></div></div><p> 230 When the user elects to make the client a Domain Member, Windows 200x prompts for 231 an account and password that has privileges to create machine accounts in the domain. 232 A Samba Administrator Account (i.e., a Samba account that has <tt class="constant">root</tt> privileges on the 233 Samba server) must be entered here; the operation will fail if an ordinary user 234 account is given. 235 </p><p> 236 For security reasons, the password for this Administrator Account should be set 237 to a password that is other than that used for the root user in <tt class="filename">/etc/passwd</tt>. 238 </p><p> 239 The name of the account that is used to create Domain Member machine accounts can be 240 anything the network administrator may choose. If it is other than <tt class="constant">root</tt> 241 then this is easily mapped to <tt class="constant">root</tt> in the file named in the <tt class="filename">smb.conf</tt> parameter 242 <a class="indexterm" name="id2541684"></a>username map = /etc/samba/smbusers. 243 </p><p> 244 The session key of the Samba Administrator Account acts as an encryption key for setting the password of the machine trust 245 account. The Machine Trust Account will be created on-the-fly, or updated if it already exists. 246 </p></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2541701"></a>Windows NT4 Client</h4></div></div></div><p> 247 If the Machine Trust Account was created manually, on the 248 Identification Changes menu enter the domain name, but do not 249 check the box <span class="guilabel">Create a Computer Account in the Domain</span>. 250 In this case, the existing Machine Trust Account is used to join the machine 251 to the domain. 252 </p><p> 253 If the Machine Trust Account is to be created on-the-fly, on the Identification Changes menu enter the domain 254 name and check the box <span class="guilabel">Create a Computer Account in the Domain</span>. In this case, joining 255 the domain proceeds as above for Windows 2000 (i.e., you must supply a Samba Administrator Account when 256 prompted). 257 </p></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2541736"></a>Samba Client</h4></div></div></div><p>Joining a Samba client to a domain is documented in 258 <a href="domain-member.html#domain-member-server" title="Domain Member Server">Domain Member Server</a>. 259 </p></div></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="domain-member-server"></a>Domain Member Server</h2></div></div></div><p> 260This mode of server operation involves the Samba machine being made a member 261of a domain security context. This means by definition that all user 262authentication will be done from a centrally defined authentication regime. 263The authentication regime may come from an NT3/4-style (old domain technology) 264server, or it may be provided from an Active Directory server (ADS) running on 265MS Windows 2000 or later. 266</p><p> 267<span class="emphasis"><em> 268Of course it should be clear that the authentication backend itself could be 269from any distributed directory architecture server that is supported by Samba. 270This can be LDAP (from OpenLDAP), or Sun's iPlanet, or NetWare Directory 271Server, and so on. 272</em></span> 273</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p> 274When Samba is configured to use an LDAP, or other identity management and/or 275directory service, it is Samba that continues to perform user and machine 276authentication. It should be noted that the LDAP server does not perform 277authentication handling in place of what Samba is designed to do. 278</p></div><p> 279Please refer to <a href="samba-pdc.html" title="Chapter�4.�Domain Control">Domain Control</a>, for more information regarding 280how to create a domain machine account for a Domain Member server as well as for 281information on how to enable the Samba Domain Member machine to join the domain 282and be fully trusted by it. 283</p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2541812"></a>Joining an NT4-type Domain with Samba-3</h3></div></div></div><p><a href="domain-member.html#assumptions" title="Table�6.1.�Assumptions">Next table</a> lists names that have been used in the remainder of this chapter.</p><div class="table"><a name="assumptions"></a><p class="title"><b>Table�6.1.�Assumptions</b></p><table summary="Assumptions" border="1"><colgroup><col align="right"><col align="left"></colgroup><tbody><tr><td align="right">NetBIOS name:</td><td align="left">SERV1</td></tr><tr><td align="right">Windows 200x/NT domain name:</td><td align="left">MIDEARTH</td></tr><tr><td align="right">Domain's PDC NetBIOS name:</td><td align="left">DOMPDC</td></tr><tr><td align="right">Domain's BDC NetBIOS names:</td><td align="left">DOMBDC1 and DOMBDC2</td></tr></tbody></table></div><p> 284First, you must edit your <tt class="filename">smb.conf</tt> file to tell Samba it should now use domain security. 285</p><p> 286 Change (or add) your 287 <a class="indexterm" name="id2541908"></a>security line in the [global] section 288of your <tt class="filename">smb.conf</tt> to read: 289</p><p> 290</p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id2541930"></a><i class="parameter"><tt> 291 292 security = domain</tt></i></td></tr></table><p> 293</p><p> 294Next change the <a class="indexterm" name="id2541949"></a>workgroup line in the <i class="parameter"><tt>[global]</tt></i> 295section to read: 296</p><p> 297</p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id2541972"></a><i class="parameter"><tt> 298 299 workgroup = MIDEARTH</tt></i></td></tr></table><p> 300</p><p> 301This is the name of the domain we are joining. 302</p><p> 303You must also have the parameter <a class="indexterm" name="id2541995"></a>encrypt passwords 304set to <tt class="constant">yes</tt> in order for your users to authenticate to the NT PDC. 305This is the default setting if this parameter is not specified. There is no need to specify this 306parameter, but if it is specified in the <tt class="filename">smb.conf</tt> file, it must be set to <tt class="constant">Yes</tt>. 307</p><p> 308Finally, add (or modify) a <a class="indexterm" name="id2542023"></a>password server line in the [global] 309section to read: 310</p><p> 311</p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id2542039"></a><i class="parameter"><tt> 312 313 password server = DOMPDC DOMBDC1 DOMBDC2</tt></i></td></tr></table><p> 314</p><p> 315These are the primary and backup Domain Controllers Samba 316will attempt to contact in order to authenticate users. Samba will 317try to contact each of these servers in order, so you may want to 318rearrange this list in order to spread out the authentication load 319among Domain Controllers. 320</p><p> 321Alternately, if you want smbd to automatically determine 322the list of Domain Controllers to use for authentication, you may 323set this line to be: 324</p><p> 325</p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id2542078"></a><i class="parameter"><tt> 326 327 password server = *</tt></i></td></tr></table><p> 328</p><p> 329This method allows Samba to use exactly the same mechanism that NT does. The 330method either uses broadcast-based name resolution, performs a WINS database 331lookup in order to find a Domain Controller against which to authenticate, 332or locates the Domain Controller using DNS name resolution. 333</p><p> 334To join the domain, run this command: 335</p><p> 336</p><pre class="screen"> 337<tt class="prompt">root# </tt><b class="userinput"><tt>net join -S DOMPDC -U<i class="replaceable"><tt>Administrator%password</tt></i></tt></b> 338</pre><p> 339</p><p> 340If the <tt class="option">-S DOMPDC</tt> argument is not given, the domain name will be obtained from <tt class="filename">smb.conf</tt>. 341</p><p> 342The machine is joining the domain DOM, and the PDC for that domain (the only machine 343that has write access to the domain SAM database) is DOMPDC, therefore use the <tt class="option">-S</tt> 344option. The <i class="replaceable"><tt>Administrator%password</tt></i> is the login name and 345password for an account that has the necessary privilege to add machines to the 346domain. If this is successful, you will see the message in your terminal window the 347text shown below. Where the older NT4 style domain architecture is used: 348</p><pre class="screen"> 349<tt class="computeroutput">Joined domain DOM.</tt> 350</pre><p> 351</p><p> 352Where Active Directory is used: 353</p><pre class="screen"> 354<tt class="computeroutput">Joined SERV1 to realm MYREALM.</tt> 355</pre><p> 356</p><p> 357Refer to the <span><b class="command">net</b></span> man page for further information. 358</p><p> 359This process joins the server to the domain without having to create the machine 360trust account on the PDC beforehand. 361</p><p> 362This command goes through the machine account password change protocol, then writes 363the new (random) machine account password for this Samba server into a file in the 364same directory in which a smbpasswd file would be normally stored: 365</p><pre class="screen"> 366<tt class="filename">/usr/local/samba/private/secrets.tdb</tt> 367or 368<tt class="filename">/etc/samba/secrets.tdb</tt>. 369</pre><p> 370</p><p> 371This file is created and owned by root and is not readable by any other user. It is 372the key to the Domain-level security for your system, and should be treated as carefully 373as a shadow password file. 374</p><p> 375Finally, restart your Samba daemons and get ready for clients to begin using domain 376security. The way you can restart your Samba daemons depends on your distribution, 377but in most cases the following will suffice: 378</p><pre class="screen"> 379<tt class="prompt">root# </tt>/etc/init.d/samba restart 380</pre><p> 381</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2542255"></a>Why Is This Better Than <i class="parameter"><tt>security = server</tt></i>?</h3></div></div></div><p> 382Currently, domain security in Samba does not free you from 383having to create local UNIX users to represent the users attaching 384to your server. This means that if Domain user <tt class="constant">DOM\fred 385</tt> attaches to your Domain Security Samba server, there needs 386to be a local UNIX user fred to represent that user in the UNIX 387file system. This is similar to the older Samba security mode 388<a class="indexterm" name="id2542278"></a>security = server, 389where Samba would pass through the authentication request to a Windows 390NT server in the same way as a Windows 95 or Windows 98 server would. 391</p><p> 392Please refer to <a href="winbind.html" title="Chapter�22.�Winbind: Use of Domain Accounts">Winbind: Use of Domain Accounts</a> chapter, for information on a system 393to automatically assign UNIX UIDs and GIDs to Windows NT Domain users and groups. 394</p><p> 395The advantage to Domain-level security is that the 396authentication in Domain-level security is passed down the authenticated 397RPC channel in exactly the same way that an NT server would do it. This 398means Samba servers now participate in domain trust relationships in 399exactly the same way NT servers do (i.e., you can add Samba servers into 400a resource domain and have the authentication passed on from a resource 401domain PDC to an account domain PDC). 402</p><p> 403In addition, with <a class="indexterm" name="id2542316"></a>security = server, every Samba 404daemon on a server has to keep a connection open to the 405authenticating server for as long as that daemon lasts. This can drain 406the connection resources on a Microsoft NT server and cause it to run 407out of available connections. With <a class="indexterm" name="id2542327"></a>security = domain, 408however, the Samba daemons connect to the PDC/BDC only for as long 409as is necessary to authenticate the user and then drop the connection, 410thus conserving PDC connection resources. 411</p><p> 412And finally, acting in the same manner as an NT server 413authenticating to a PDC means that as part of the authentication 414reply, the Samba server gets the user identification information such 415as the user SID, the list of NT groups the user belongs to, and so on. 416</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p> 417Much of the text of this document was first published in the Web magazine 418<a href="http://www.linuxworld.com" target="_top">LinuxWorld</a> as the article <a href="http://www.linuxworld.com/linuxworld/lw-1998-10/lw-10-samba.html" target="_top">http://www.linuxworld.com/linuxworld/lw-1998-10/lw-10-samba.html</a> 419<span class="emphasis"><em>Doing the NIS/NT Samba</em></span>. 420</p></div></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="ads-member"></a>Samba ADS Domain Membership</h2></div></div></div><p> 421<a class="indexterm" name="id2542383"></a> 422<a class="indexterm" name="id2542390"></a> 423<a class="indexterm" name="id2542399"></a> 424<a class="indexterm" name="id2542406"></a> 425This is a rough guide to setting up Samba-3 with Kerberos authentication against a 426Windows 200x KDC. A familiarity with Kerberos is assumed. 427</p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2542416"></a>Configure <tt class="filename">smb.conf</tt></h3></div></div></div><p> 428You must use at least the following three options in <tt class="filename">smb.conf</tt>: 429</p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id2542443"></a><i class="parameter"><tt> 430 431 realm = your.kerberos.REALM</tt></i></td></tr><tr><td><a class="indexterm" name="id2542458"></a><i class="parameter"><tt> 432 433 security = ADS</tt></i></td></tr><tr><td># The following parameter need only be specified if present.</td></tr><tr><td># The default setting is not present is Yes.</td></tr><tr><td><a class="indexterm" name="id2542488"></a><i class="parameter"><tt> 434 435 encrypt passwords = yes</tt></i></td></tr></table><p> 436In case samba cannot correctly identify the appropriate ADS server using the realm name, use the 437<a class="indexterm" name="id2542507"></a>password server option in <tt class="filename">smb.conf</tt>: 438</p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id2542525"></a><i class="parameter"><tt> 439 440 password server = your.kerberos.server</tt></i></td></tr></table><p> 441</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p> 442You do <span class="emphasis"><em>not</em></span> need a smbpasswd file, and older clients will be authenticated as 443if <a class="indexterm" name="id2542550"></a>security = domain, although it will not do any harm and 444allows you to have local users not in the domain. 445</p></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2542561"></a>Configure <tt class="filename">/etc/krb5.conf</tt></h3></div></div></div><p> 446<a class="indexterm" name="id2542574"></a> 447<a class="indexterm" name="id2542581"></a> 448With both MIT and Heimdal Kerberos, it is unnecessary to configure the 449<tt class="filename">/etc/krb5.conf</tt>, and it may be detrimental. 450</p><p> 451Microsoft Active Directory servers automatically create SRV records in the DNS zone 452<i class="parameter"><tt>_kerberos.REALM.NAME</tt></i> for each KDC in the realm. This is part 453of the installation and configuration process used to create an Active Directory Domain. 454</p><p> 455MIT's, as well as Heimdal's, recent KRB5 libraries default to checking for SRV records, so they will 456automatically find the KDCs. In addition, <tt class="filename">krb5.conf</tt> only allows specifying 457a single KDC, even there if there may be more than one. Using the DNS lookup allows the KRB5 458libraries to use whichever KDCs are available. 459</p><p> 460When manually configuring <tt class="filename">krb5.conf</tt>, the minimal configuration is: 461</p><p> 462 463 </p><pre class="programlisting"> 464[libdefaults] 465 default_realm = YOUR.KERBEROS.REALM 466 467[realms] 468 YOUR.KERBEROS.REALM = { 469 kdc = your.kerberos.server 470 } 471 472[domain_realms] 473 .kerberos.server = YOUR.KERBEROS.REALM 474</pre><p> 475When using Heimdal versions before 0.6 use the following configuration settings: 476</p><pre class="screen"> 477[libdefaults] 478 default_realm = YOUR.KERBEROS.REALM 479 default_etypes = des-cbc-crc des-cbc-md5 480 default_etypes_des = des-cbc-crc des-cbc-md5 481 482[realms] 483 YOUR.KERBEROS.REALM = { 484 kdc = your.kerberos.server 485 } 486 487[domain_realms] 488 .kerberos.server = YOUR.KERBEROS.REALM 489</pre><p> 490</p><p> 491<a class="indexterm" name="id2542665"></a> 492Test your config by doing a <b class="userinput"><tt>kinit 493<i class="replaceable"><tt>USERNAME</tt></i>@<i class="replaceable"><tt>REALM</tt></i></tt></b> and 494making sure that your password is accepted by the Win2000 KDC. 495</p><p> 496With Heimdal versions earlier than 0.6.x you only can use newly created accounts 497in ADS or accounts that have had the password changed once after migration, or 498in case of <tt class="constant">Administrator</tt> after installation. At the 499moment, a Windows 2003 KDC can only be used with a Heimdal releases later than 0.6 500(and no default etypes in krb5.conf). Unfortunately this whole area is still 501in a state of flux. 502</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p> 503The realm must be in uppercase or you will get “<span class="quote"><span class="emphasis"><em><span class="errorname">Cannot find KDC for 504requested realm while getting initial credentials</span></em></span></span>” error (Kerberos 505is case-sensitive!). 506</p></div><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p> 507Time between the two servers must be synchronized. You will get a 508“<span class="quote"><span class="emphasis"><em><span class="errorname">kinit(v5): Clock skew too great while getting initial credentials</span></em></span></span>” 509if the time difference is more than five minutes. 510</p></div><p> 511Clock skew limits are configurable in the Kerberos protocols. The default setting is 512five minutes. 513</p><p> 514You also must ensure that you can do a reverse DNS lookup on the IP 515address of your KDC. Also, the name that this reverse lookup maps to 516must either be the NetBIOS name of the KDC (i.e., the hostname with no 517domain attached) or it can alternately be the NetBIOS name followed by the realm. 518</p><p> 519The easiest way to ensure you get this right is to add a 520<tt class="filename">/etc/hosts</tt> entry mapping the IP address of your KDC to 521its NetBIOS name. If you do not get this correct then you will get a 522<span class="errorname">local error</span> when you try to join the realm. 523</p><p> 524If all you want is Kerberos support in <span class="application">smbclient</span> then you can skip 525directly to <a href="domain-member.html#ads-test-smbclient" title="Testing with smbclient">Testing with <span class="application">smbclient</span></a> now. 526<a href="domain-member.html#ads-create-machine-account" title="Create the Computer Account">Create the Computer Account</a> and 527<a href="domain-member.html#ads-test-server" title="Testing Server Setup">Testing Server Setup</a> 528are needed only if you want Kerberos support for <span class="application">smbd</span> and <span class="application">winbindd</span>. 529</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="ads-create-machine-account"></a>Create the Computer Account</h3></div></div></div><p> 530As a user who has write permission on the Samba private directory (usually root), run: 531</p><pre class="screen"> 532<tt class="prompt">root# </tt> <b class="userinput"><tt>net ads join -U Administrator%password</tt></b> 533</pre><p> 534</p><p> 535When making a Windows client a member of an ADS domain within a complex organization, you 536may want to create the machine account within a particular organizational unit. Samba-3 permits 537this to be done using the following syntax: 538</p><pre class="screen"> 539<tt class="prompt">root# </tt> <b class="userinput"><tt>kinit Administrator@your.kerberos.REALM</tt></b> 540<tt class="prompt">root# </tt> <b class="userinput"><tt>net ads join "organizational_unit"</tt></b> 541</pre><p> 542</p><p> 543For example, you may want to create the machine account in a container called “<span class="quote"><span class="emphasis"><em>Servers</em></span></span>” 544under the organizational directory “<span class="quote"><span class="emphasis"><em>Computers\BusinessUnit\Department</em></span></span>” like this: 545</p><pre class="screen"> 546<tt class="prompt">root# </tt> <b class="userinput"><tt>net ads join "Computers\BusinessUnit\Department\Servers"</tt></b> 547</pre><p> 548</p><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2542917"></a>Possible Errors</h4></div></div></div><p> 549</p><div class="variablelist"><dl><dt><span class="term"><span class="errorname">ADS support not compiled in</span></span></dt><dd><p>Samba must be reconfigured (remove config.cache) and recompiled 550 (make clean all install) after the Kerberos libraries and headers files are installed. 551 </p></dd><dt><span class="term"><span class="errorname">net ads join prompts for user name</span></span></dt><dd><p>You need to login to the domain using <b class="userinput"><tt>kinit 552 <i class="replaceable"><tt>USERNAME</tt></i>@<i class="replaceable"><tt>REALM</tt></i></tt></b>. 553 <i class="replaceable"><tt>USERNAME</tt></i> must be a user who has rights to add a machine 554 to the domain. </p></dd><dt><span class="term">Unsupported encryption/or checksum types</span></dt><dd><p> 555 Make sure that the <tt class="filename">/etc/krb5.conf</tt> is correctly configured 556 for the type and version of Kerberos installed on the system. 557 </p></dd></dl></div><p> 558</p></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="ads-test-server"></a>Testing Server Setup</h3></div></div></div><p> 559If the join was successful, you will see a new computer account with the 560NetBIOS name of your Samba server in Active Directory (in the “<span class="quote"><span class="emphasis"><em>Computers</em></span></span>” 561folder under Users and Computers. 562</p><p> 563On a Windows 2000 client, try <b class="userinput"><tt>net use * \\server\share</tt></b>. You should 564be logged in with Kerberos without needing to know a password. If this fails then run 565<b class="userinput"><tt>klist tickets</tt></b>. Did you get a ticket for the server? Does it have 566an encryption type of DES-CBC-MD5? 567</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p> 568Samba can use both DES-CBC-MD5 encryption as well as ARCFOUR-HMAC-MD5 encoding. 569</p></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="ads-test-smbclient"></a>Testing with <span class="application">smbclient</span></h3></div></div></div><p> 570<a class="indexterm" name="id2543051"></a> 571On your Samba server try to login to a Win2000 server or your Samba 572server using <span class="application">smbclient</span> and Kerberos. Use <span class="application">smbclient</span> as usual, but 573specify the <tt class="option">-k</tt> option to choose Kerberos authentication. 574</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2543078"></a>Notes</h3></div></div></div><p> 575You must change administrator password at least once after DC 576install, to create the right encryption types. 577</p><p> 578Windows 200x does not seem to create the <i class="parameter"><tt>_kerberos._udp</tt></i> and <i class="parameter"><tt>_ldap._tcp</tt></i> in 579the default DNS setup. Perhaps this will be fixed later in service packs. 580</p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2543108"></a>Sharing User ID Mappings between Samba Domain Members</h2></div></div></div><p> 581Samba maps UNIX users and groups (identified by UIDs and GIDs) to Windows users and groups (identified by SIDs). 582These mappings are done by the <i class="parameter"><tt>idmap</tt></i> subsystem of Samba. 583</p><p> 584In some cases it is useful to share these mappings between Samba Domain Members, 585so <span class="emphasis"><em>name->id</em></span> mapping is identical on all machines. 586This may be needed in particular when sharing files over both CIFS and NFS. 587</p><p>To use the <span class="emphasis"><em>LDAP</em></span> <i class="parameter"><tt>ldap idmap suffix</tt></i>, set:</p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id2543155"></a><i class="parameter"><tt> 588 589 ldap idmap suffix = ou=Idmap,dc=quenya,dc=org</tt></i></td></tr></table><p>See the <tt class="filename">smb.conf</tt> man page entry for the <a class="indexterm" name="id2543180"></a>ldap idmap suffix 590parameter for further information.</p><p> 591Do not forget to specify also the <a class="indexterm" name="id2543192"></a>ldap admin dn 592and to make certain to set the LDAP administrative password into the <tt class="filename">secrets.tdb</tt> using: 593</p><pre class="screen"> 594<tt class="prompt">root# </tt> smbpasswd -w ldap-admin-password 595</pre></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2543219"></a>Common Errors</h2></div></div></div><p> 596In the process of adding/deleting/re-adding Domain Member machine accounts, there are 597many traps for the unwary player and many “<span class="quote"><span class="emphasis"><em>little</em></span></span>” things that can go wrong. 598It is particularly interesting how often subscribers on the Samba mailing list have concluded 599after repeated failed attempts to add a machine account that it is necessary to “<span class="quote"><span class="emphasis"><em>re-install</em></span></span>” 600MS Windows on the machine. In truth, it is seldom necessary to reinstall because of this type 601of problem. The real solution is often quite simple and with an understanding of how MS Windows 602networking functions, it is easy to overcome. 603</p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2543247"></a>Cannot Add Machine Back to Domain</h3></div></div></div><p> 604“<span class="quote"><span class="emphasis"><em>A Windows workstation was re-installed. The original domain machine 605account was deleted and added immediately. The workstation will not join the domain if I use 606the same machine name. Attempts to add the machine fail with a message that the machine already 607exists on the network I know it does not. Why is this failing?</em></span></span>” 608</p><p> 609The original name is still in the NetBIOS name cache and must expire after machine account 610deletion before adding that same name as a Domain Member again. The best advice is to delete 611the old account and then add the machine with a new name. 612</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2543278"></a>Adding Machine to Domain Fails</h3></div></div></div><p> 613“<span class="quote"><span class="emphasis"><em>Adding a Windows 200x or XP Professional machine to the Samba PDC Domain fails with a 614message that, <span class="errorname">`The machine could not be added at this time, there is a network problem. 615Please try again later.'</span> Why?</em></span></span>” 616</p><p> 617You should check that there is an <a class="indexterm" name="id2543300"></a>add machine script in your <tt class="filename">smb.conf</tt> 618file. If there is not, please add one that is appropriate for your OS platform. If a script 619has been defined, you will need to debug its operation. Increase the <a class="indexterm" name="id2543316"></a>log level 620in the <tt class="filename">smb.conf</tt> file to level 10, then try to rejoin the domain. Check the logs to see which 621operation is failing. 622</p><p> 623Possible causes include: 624</p><div class="itemizedlist"><ul type="disc"><li><p> 625 The script does not actually exist, or could not be located in the path specified. 626 </p><p> 627 <span class="emphasis"><em>Corrective action:</em></span> Fix it. Make sure when run manually 628 that the script will add both the UNIX system account and the Samba SAM account. 629 </p></li><li><p> 630 The machine could not be added to the UNIX system accounts file <tt class="filename">/etc/passwd</tt>. 631 </p><p> 632 <span class="emphasis"><em>Corrective action:</em></span> Check that the machine name is a legal UNIX 633 system account name. If the UNIX utility <span><b class="command">useradd</b></span> is called, 634 then make sure that the machine name you are trying to add can be added using this 635 tool. <span><b class="command">Useradd</b></span> on some systems will not allow any upper case characters 636 nor will it allow spaces in the name. 637 </p></li></ul></div><p> 638The <a class="indexterm" name="id2543391"></a>add machine script does not create the 639machine account in the Samba backend database, it is there only to create a UNIX system 640account to which the Samba backend database account can be mapped. 641</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2543403"></a>I Can't Join a Windows 2003 PDC</h3></div></div></div><p>Windows 2003 requires SMB signing. Client side SMB signing has been implemented in Samba-3.0. 642 Set <a class="indexterm" name="id2543413"></a>client use spnego = yes when communicating 643 with a Windows 2003 server.</p></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="samba-bdc.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="StandAloneServer.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter�5.�Backup Domain Control�</td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top">�Chapter�7.�Stand-alone Servers</td></tr></table></div></body></html> 644