<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Chapter 12. Group Mapping: MS Windows and UNIX</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="optional.html" title="Part III. Advanced Configuration"><link rel="prev" href="passdb.html" title="Chapter 11. Account Information Databases"><link rel="next" href="NetCommand.html" title="Chapter 13. Remote and Local Management: The Net Command"></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 12. Group Mapping: MS Windows and UNIX</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="passdb.html">Prev</a> </td><th width="60%" align="center">Part III. Advanced Configuration</th><td width="20%" align="right"> <a accesskey="n" href="NetCommand.html">Next</a></td></tr></table><hr></div><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="groupmapping"></a>Chapter 12. Group Mapping: MS Windows and UNIX</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"><<a href="mailto:jht@samba.org">jht@samba.org</a>></code></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">Jean François</span> <span class="surname">Micouleau</span></h3></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"><<a href="mailto:jerry@samba.org">jerry@samba.org</a>></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="groupmapping.html#id359469">Features and Benefits</a></span></dt><dt><span class="sect1"><a href="groupmapping.html#id359854">Discussion</a></span></dt><dd><dl><dt><span class="sect2"><a href="groupmapping.html#id360168">Warning: User Private Group Problems</a></span></dt><dt><span class="sect2"><a href="groupmapping.html#id360220">Nested Groups: Adding Windows Domain Groups to Windows Local Groups</a></span></dt><dt><span class="sect2"><a href="groupmapping.html#id360749">Important Administrative Information</a></span></dt><dt><span class="sect2"><a href="groupmapping.html#id360970">Default Users, Groups, and Relative Identifiers</a></span></dt><dt><span class="sect2"><a href="groupmapping.html#id361575">Example Configuration</a></span></dt></dl></dd><dt><span class="sect1"><a href="groupmapping.html#id361647">Configuration Scripts</a></span></dt><dd><dl><dt><span class="sect2"><a href="groupmapping.html#id361657">Sample <code class="filename">smb.conf</code> Add Group Script</a></span></dt><dt><span class="sect2"><a href="groupmapping.html#id361818">Script to Configure Group Mapping</a></span></dt></dl></dd><dt><span class="sect1"><a href="groupmapping.html#id361932">Common Errors</a></span></dt><dd><dl><dt><span class="sect2"><a href="groupmapping.html#id361943">Adding Groups Fails</a></span></dt><dt><span class="sect2"><a href="groupmapping.html#id362018">Adding Domain Users to the Workstation Power Users Group</a></span></dt></dl></dd></dl></div><p> <a class="indexterm" name="id359351"></a> <a class="indexterm" name="id359360"></a> <a class="indexterm" name="id359367"></a> <a class="indexterm" name="id359374"></a> <a class="indexterm" name="id359380"></a> <a class="indexterm" name="id359387"></a> Starting with Samba-3, new group mapping functionality is available to create associations between Windows group SIDs and UNIX group GIDs. The <code class="literal">groupmap</code> subcommand included with the <span class="application">net</span> tool can be used to manage these associations. </p><p> <a class="indexterm" name="id359410"></a> <a class="indexterm" name="id359417"></a> The new facility for mapping NT groups to UNIX system groups allows the administrator to decide which NT domain groups are to be exposed to MS Windows clients. Only those NT groups that map to a UNIX group that has a value other than the default (<code class="constant">-1</code>) will be exposed in group selection lists in tools that access domain users and groups. </p><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Warning</h3><p> <a class="indexterm" name="id359436"></a> <a class="indexterm" name="id359443"></a> The <em class="parameter"><code>domain admin group</code></em> parameter has been removed in Samba-3 and should no longer be specified in <code class="filename">smb.conf</code>. In Samba-2.2.x, this parameter was used to give the listed users membership in the <code class="constant">Domain Admins</code> Windows group, which gave local admin rights on their workstations (in default configurations). </p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id359469"></a>Features and Benefits</h2></div></div></div><p> Samba allows the administrator to create MS Windows NT4/200x group accounts and to arbitrarily associate them with UNIX/Linux group accounts. </p><p> <a class="indexterm" name="id359482"></a> <a class="indexterm" name="id359488"></a> <a class="indexterm" name="id359495"></a> <a class="indexterm" name="id359501"></a> <a class="indexterm" name="id359508"></a> <a class="indexterm" name="id359515"></a> <a class="indexterm" name="id359522"></a> Group accounts can be managed using the MS Windows NT4 or MS Windows 200x/XP Professional MMC tools. Appropriate interface scripts should be provided in <code class="filename">smb.conf</code> if it is desired that UNIX/Linux system accounts should be automatically created when these tools are used. In the absence of these scripts, and so long as <code class="literal">winbindd</code> is running, Samba group accounts that are created using these tools will be allocated UNIX UIDs and GIDs from the ID range specified by the <a class="indexterm" name="id359544"></a>idmap uid/<a class="indexterm" name="id359551"></a>idmap gid parameters in the <code class="filename">smb.conf</code> file. </p><div class="figure"><a name="idmap-sid2gid"></a><p class="title"><b>Figure 12.1. IDMAP: Group SID-to-GID Resolution.</b></p><div class="figure-contents"><div class="mediaobject"><img src="images/idmap-sid2gid.png" width="270" alt="IDMAP: Group SID-to-GID Resolution."></div></div></div><br class="figure-break"><div class="figure"><a name="idmap-gid2sid"></a><p class="title"><b>Figure 12.2. IDMAP: GID Resolution to Matching SID.</b></p><div class="figure-contents"><div class="mediaobject"><img src="images/idmap-gid2sid.png" width="270" alt="IDMAP: GID Resolution to Matching SID."></div></div></div><br class="figure-break"><p> <a class="indexterm" name="id359649"></a> <a class="indexterm" name="id359656"></a> <a class="indexterm" name="id359662"></a> <a class="indexterm" name="id359671"></a> In both cases, when winbindd is not running, only locally resolvable groups can be recognized. Please refer to <a href="groupmapping.html#idmap-sid2gid" title="Figure 12.1. IDMAP: Group SID-to-GID Resolution.">IDMAP: Group SID-to-GID Resolution</a> and <a href="groupmapping.html#idmap-gid2sid" title="Figure 12.2. IDMAP: GID Resolution to Matching SID.">IDMAP: GID Resolution to Matching SID</a>. The <code class="literal">net groupmap</code> is used to establish UNIX group to NT SID mappings as shown in <a href="groupmapping.html#idmap-store-gid2sid" title="Figure 12.3. IDMAP Storing Group Mappings.">IDMAP: storing group mappings</a>. </p><div class="figure"><a name="idmap-store-gid2sid"></a><p class="title"><b>Figure 12.3. IDMAP Storing Group Mappings.</b></p><div class="figure-contents"><div class="mediaobject"><img src="images/idmap-store-gid2sid.png" width="270" alt="IDMAP Storing Group Mappings."></div></div></div><br class="figure-break"><p> <a class="indexterm" name="id359752"></a> <a class="indexterm" name="id359759"></a> <a class="indexterm" name="id359766"></a> <a class="indexterm" name="id359772"></a> Administrators should be aware that where <code class="filename">smb.conf</code> group interface scripts make direct calls to the UNIX/Linux system tools (the shadow utilities, <code class="literal">groupadd</code>, <code class="literal">groupdel</code>, and <code class="literal">groupmod</code>), the resulting UNIX/Linux group names will be subject to any limits imposed by these tools. If the tool does not allow uppercase characters or space characters, then the creation of an MS Windows NT4/200x-style group of <code class="literal">Engineering Managers</code> will attempt to create an identically named UNIX/Linux group, an attempt that will of course fail. </p><p> <a class="indexterm" name="id359816"></a> <a class="indexterm" name="id359822"></a> There are several possible workarounds for the operating system tools limitation. One method is to use a script that generates a name for the UNIX/Linux system group that fits the operating system limits and that then just passes the UNIX/Linux group ID (GID) back to the calling Samba interface. This will provide a dynamic workaround solution. </p><p> <a class="indexterm" name="id359835"></a> Another workaround is to manually create a UNIX/Linux group, then manually create the MS Windows NT4/200x group on the Samba server, and then use the <code class="literal">net groupmap</code> tool to connect the two to each other. </p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id359854"></a>Discussion</h2></div></div></div><p> <a class="indexterm" name="id359862"></a> <a class="indexterm" name="id359868"></a> When you install <span class="application">MS Windows NT4/200x</span> on a computer, the installation program creates default users and groups, notably the <code class="constant">Administrators</code> group, and gives that group privileges necessary to perform essential system tasks, such as the ability to change the date and time or to kill (or close) any process running on the local machine. </p><p> <a class="indexterm" name="id359891"></a> The <code class="constant">Administrator</code> user is a member of the <code class="constant">Administrators</code> group, and thus inherits <code class="constant">Administrators</code> group privileges. If a <code class="constant">joe</code> user is created to be a member of the <code class="constant">Administrators</code> group, <code class="constant">joe</code> has exactly the same rights as the user <code class="constant">Administrator</code>. </p><p> <a class="indexterm" name="id359927"></a> <a class="indexterm" name="id359934"></a> <a class="indexterm" name="id359941"></a> <a class="indexterm" name="id359948"></a> When an MS Windows NT4/200x/XP machine is made a domain member, the “<span class="quote">Domain Admins</span>” group of the PDC is added to the local <code class="constant">Administrators</code> group of the workstation. Every member of the <code class="constant">Domain Admins</code> group inherits the rights of the local <code class="constant">Administrators</code> group when logging on the workstation. </p><p> <a class="indexterm" name="id359974"></a> <a class="indexterm" name="id359981"></a> The following steps describe how to make Samba PDC users members of the <code class="constant">Domain Admins</code> group. </p><div class="orderedlist"><ol type="1"><li><p> Create a UNIX group (usually in <code class="filename">/etc/group</code>); let's call it <code class="constant">domadm</code>. </p></li><li><p> <a class="indexterm" name="id360017"></a> Add to this group the users that must be “<span class="quote">Administrators</span>”. For example, if you want <code class="constant">joe, john</code>, and <code class="constant">mary</code> to be administrators, your entry in <code class="filename">/etc/group</code> will look like this: </p><pre class="programlisting"> domadm:x:502:joe,john,mary </pre><p> </p></li><li><p> Map this domadm group to the “<span class="quote">Domain Admins</span>” group by executing the command: </p><p> </p><pre class="screen"> <code class="prompt">root# </code><strong class="userinput"><code>net groupmap add ntgroup="Domain Admins" unixgroup=domadm rid=512 type=d</code></strong> </pre><p> </p><p> <a class="indexterm" name="id360082"></a> The quotes around “<span class="quote">Domain Admins</span>” are necessary due to the space in the group name. Also make sure to leave no white space surrounding the equal character (=). </p></li></ol></div><p> Now <code class="constant">joe, john</code>, and <code class="constant">mary</code> are domain administrators. </p><p> <a class="indexterm" name="id360109"></a> It is possible to map any arbitrary UNIX group to any Windows NT4/200x group as well as to make any UNIX group a Windows domain group. For example, if you wanted to include a UNIX group (e.g., acct) in an ACL on a local file or printer on a Domain Member machine, you would flag that group as a domain group by running the following on the Samba PDC: </p><p> </p><pre class="screen"> <code class="prompt">root# </code><strong class="userinput"><code>net groupmap add rid=1000 ntgroup="Accounting" unixgroup=acct type=d</code></strong> </pre><p> The <code class="literal">ntgroup</code> value must be in quotes if it contains space characters to prevent the space from being interpreted as a command delimiter. </p><p> <a class="indexterm" name="id360151"></a> <a class="indexterm" name="id360157"></a> Be aware that the RID parameter is an unsigned 32-bit integer that should normally start at 1000. However, this RID must not overlap with any RID assigned to a user. Verification for this is done differently depending on the passdb backend you are using. Future versions of the tools may perform the verification automatically, but for now the burden is on you. </p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id360168"></a>Warning: User Private Group Problems</h3></div></div></div><p> <a class="indexterm" name="id360176"></a> <a class="indexterm" name="id360183"></a> <a class="indexterm" name="id360190"></a> Windows does not permit user and group accounts to have the same name. This has serious implications for all sites that use private group accounts. A private group account is an administrative practice whereby users are each given their own group account. Red Hat Linux, as well as several free distributions of Linux, by default create private groups. </p><p> <a class="indexterm" name="id360203"></a> <a class="indexterm" name="id360210"></a> When mapping a UNIX/Linux group to a Windows group account, all conflict can be avoided by assuring that the Windows domain group name does not overlap with any user account name. </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id360220"></a>Nested Groups: Adding Windows Domain Groups to Windows Local Groups</h3></div></div></div><a class="indexterm" name="id360226"></a><p> <a class="indexterm" name="id360238"></a> This functionality is known as <code class="constant">nested groups</code> and was first added to Samba-3.0.3. </p><p> <a class="indexterm" name="id360252"></a> All MS Windows products since the release of Windows NT 3.10 support the use of nested groups. Many Windows network administrators depend on this capability because it greatly simplifies security administration. </p><p> <a class="indexterm" name="id360264"></a> <a class="indexterm" name="id360271"></a> <a class="indexterm" name="id360278"></a> <a class="indexterm" name="id360284"></a> <a class="indexterm" name="id360291"></a> <a class="indexterm" name="id360298"></a> <a class="indexterm" name="id360305"></a> The nested group architecture was designed with the premise that day-to-day user and group membership management should be performed on the domain security database. The application of group security should be implemented on domain member servers using only local groups. On the domain member server, all file system security controls are then limited to use of the local groups, which will contain domain global groups and domain global users. </p><p> <a class="indexterm" name="id360319"></a> <a class="indexterm" name="id360326"></a> <a class="indexterm" name="id360332"></a> You may ask, What are the benefits of this arrangement? The answer is obvious to those who have plumbed the dark depths of Windows networking architecture. Consider for a moment a server on which are stored 200,000 files, each with individual domain user and domain group settings. The company that owns the file server is bought by another company, resulting in the server being moved to another location, and then it is made a member of a different domain. Who would you think now owns all the files and directories? Answer: Account Unknown. </p><p> <a class="indexterm" name="id360347"></a> <a class="indexterm" name="id360354"></a> <a class="indexterm" name="id360361"></a> <a class="indexterm" name="id360367"></a> Unraveling the file ownership mess is an unenviable administrative task that can be avoided simply by using local groups to control all file and directory access control. In this case, only the members of the local groups will have been lost. The files and directories in the storage subsystem will still be owned by the local groups. The same goes for all ACLs on them. It is administratively much simpler to delete the <code class="constant">Account Unknown</code> membership entries inside local groups with appropriate entries for domain global groups in the new domain that the server has been made a member of. </p><p> <a class="indexterm" name="id360386"></a> <a class="indexterm" name="id360393"></a> <a class="indexterm" name="id360400"></a> <a class="indexterm" name="id360407"></a> <a class="indexterm" name="id360414"></a> <a class="indexterm" name="id360420"></a> <a class="indexterm" name="id360427"></a> <a class="indexterm" name="id360434"></a> Another prominent example of the use of nested groups involves implementation of administrative privileges on domain member workstations and servers. Administrative privileges are given to all members of the built-in local group <code class="constant">Administrators</code> on each domain member machine. To ensure that all domain administrators have full rights on the member server or workstation, on joining the domain, the <code class="constant">Domain Admins</code> group is added to the local Administrators group. Thus everyone who is logged into the domain as a member of the Domain Admins group is also granted local administrative privileges on each domain member. </p><p> <a class="indexterm" name="id360456"></a> <a class="indexterm" name="id360463"></a> <a class="indexterm" name="id360470"></a> <a class="indexterm" name="id360477"></a> UNIX/Linux has no concept of support for nested groups, and thus Samba has for a long time not supported them either. The problem is that you would have to enter UNIX groups as auxiliary members of a group in <code class="filename">/etc/group</code>. This does not work because it was not a design requirement at the time the UNIX file system security model was implemented. Since Samba-2.2, the winbind daemon can provide <code class="filename">/etc/group</code> entries on demand by obtaining user and group information from the domain controller that the Samba server is a member of. </p><p> <a class="indexterm" name="id360503"></a> <a class="indexterm" name="id360510"></a> <a class="indexterm" name="id360517"></a> <a class="indexterm" name="id360523"></a> <a class="indexterm" name="id360530"></a> In effect, Samba supplements the <code class="filename">/etc/group</code> data via the dynamic <code class="literal">libnss_winbind</code> mechanism. Beginning with Samba-3.0.3, this facility is used to provide local groups in the same manner as Windows. It works by expanding the local groups on the fly as they are accessed. For example, the <code class="constant">Domain Users</code> group of the domain is made a member of the local group <code class="constant">demo</code>. Whenever Samba needs to resolve membership of the <code class="constant">demo</code> local (alias) group, winbind asks the domain controller for demo members of the Domain Users group. By definition, it can only contain user objects, which can then be faked to be member of the UNIX/Linux group <code class="constant">demo</code>. </p><p> <a class="indexterm" name="id360571"></a> <a class="indexterm" name="id360578"></a> <a class="indexterm" name="id360585"></a> <a class="indexterm" name="id360591"></a> <a class="indexterm" name="id360598"></a> <a class="indexterm" name="id360605"></a> <a class="indexterm" name="id360612"></a> To enable the use of nested groups, <code class="literal">winbindd</code> must be used with NSS winbind. Creation and administration of the local groups is done best via the Windows Domain User Manager or its Samba equivalent, the utility <code class="literal">net rpc group</code>. Creating the local group <code class="constant">demo</code> is achieved by executing: </p><pre class="screen"> <code class="prompt">root# </code> net rpc group add demo -L -Uroot%not24get </pre><p> <a class="indexterm" name="id360652"></a> <a class="indexterm" name="id360659"></a> Here the -L switch means that you want to create a local group. It may be necessary to add -S and -U switches for accessing the correct host with appropriate user or root privileges. Adding and removing group members can be done via the <code class="constant">addmem</code> and <code class="constant">delmem</code> subcommands of <code class="literal">net rpc group</code> command. For example, addition of “<span class="quote">DOM\Domain Users</span>” to the local group <code class="constant">demo</code> is done by executing: </p><pre class="screen"> net rpc group addmem demo "DOM\Domain Users" </pre><p> <a class="indexterm" name="id360695"></a> <a class="indexterm" name="id360702"></a> <a class="indexterm" name="id360709"></a> <a class="indexterm" name="id360716"></a> Having completed these two steps, the execution of <code class="literal">getent group demo</code> will show demo members of the global <code class="constant">Domain Users</code> group as members of the group <code class="constant">demo</code>. This also works with any local or domain user. In case the domain DOM trusts another domain, it is also possible to add global users and groups of the trusted domain as members of <code class="constant">demo</code>. The users from the foreign domain who are members of the group that has been added to the <code class="constant">demo</code> group now have the same local access permissions as local domain users have. </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id360749"></a>Important Administrative Information</h3></div></div></div><p> Administrative rights are necessary in two specific forms: </p><div class="orderedlist"><ol type="1"><li><p>For Samba-3 domain controllers and domain member servers/clients.</p></li><li><p>To manage domain member Windows workstations.</p></li></ol></div><p> <a class="indexterm" name="id360778"></a> <a class="indexterm" name="id360785"></a> <a class="indexterm" name="id360792"></a> Versions of Samba up to and including 3.0.10 do not provide a means for assigning rights and privileges that are necessary for system administration tasks from a Windows domain member client machine, so domain administration tasks such as adding, deleting, and changing user and group account information, and managing workstation domain membership accounts, can be handled by any account other than root. </p><p> <a class="indexterm" name="id360805"></a> <a class="indexterm" name="id360812"></a> <a class="indexterm" name="id360819"></a> Samba-3.0.11 introduced a new privilege management interface (see <a href="rights.html" title="Chapter 15. User Rights and Privileges">User Rights and Privileges</a>) that permits these tasks to be delegated to non-root (i.e., accounts other than the equivalent of the MS Windows Administrator) accounts. </p><p> <a class="indexterm" name="id360838"></a> <a class="indexterm" name="id360845"></a> Administrative tasks on a Windows domain member workstation can be done by anyone who is a member of the <code class="constant">Domain Admins</code> group. This group can be mapped to any convenient UNIX group. </p><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id360858"></a>Applicable Only to Versions Earlier than 3.0.11</h4></div></div></div><p> <a class="indexterm" name="id360866"></a> Administrative tasks on UNIX/Linux systems, such as adding users or groups, requires <code class="constant">root</code>-level privilege. The addition of a Windows client to a Samba domain involves the addition of a user account for the Windows client. </p><p> <a class="indexterm" name="id360881"></a> <a class="indexterm" name="id360888"></a> Many UNIX administrators continue to request that the Samba Team make it possible to add Windows workstations, or the ability to add, delete, or modify user accounts, without requiring <code class="constant">root</code> privileges. Such a request violates every understanding of basic UNIX system security. </p><p> <a class="indexterm" name="id360904"></a> <a class="indexterm" name="id360911"></a> <a class="indexterm" name="id360918"></a> <a class="indexterm" name="id360925"></a> <a class="indexterm" name="id360931"></a> <a class="indexterm" name="id360938"></a> There is no safe way to provide access on a UNIX/Linux system without providing <code class="constant">root</code>-level privileges. Provision of <code class="constant">root</code> privileges can be done either by logging on to the Domain as the user <code class="constant">root</code> or by permitting particular users to use a UNIX account that has a UID=0 in the <code class="filename">/etc/passwd</code> database. Users of such accounts can use tools like the NT4 Domain User Manager and the NT4 Domain Server Manager to manage user and group accounts as well as domain member server and client accounts. This level of privilege is also needed to manage share-level ACLs. </p></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id360970"></a>Default Users, Groups, and Relative Identifiers</h3></div></div></div><p> <a class="indexterm" name="id360978"></a> <a class="indexterm" name="id360986"></a> <a class="indexterm" name="id360993"></a> <a class="indexterm" name="id361000"></a> <a class="indexterm" name="id361007"></a> <a class="indexterm" name="id361013"></a> <a class="indexterm" name="id361020"></a> <a class="indexterm" name="id361027"></a> When first installed, Windows NT4/200x/XP are preconfigured with certain user, group, and alias entities. Each has a well-known RID. These must be preserved for continued integrity of operation. Samba must be provisioned with certain essential domain groups that require the appropriate RID value. When Samba-3 is configured to use <code class="constant">tdbsam</code>, the essential domain groups are automatically created. It is the LDAP administrator's responsibility to create (provision) the default NT groups. </p><p> <a class="indexterm" name="id361045"></a> <a class="indexterm" name="id361052"></a> <a class="indexterm" name="id361058"></a> <a class="indexterm" name="id361065"></a> Each essential domain group must be assigned its respective well-known RID. The default users, groups, aliases, and RIDs are shown in <a href="groupmapping.html#WKURIDS" title="Table 12.1. Well-Known User Default RIDs">Well-Known User Default RIDs</a>. </p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p> <a class="indexterm" name="id361085"></a> <a class="indexterm" name="id361092"></a> <a class="indexterm" name="id361098"></a> <a class="indexterm" name="id361105"></a> <a class="indexterm" name="id361112"></a> It is the administrator's responsibility to create the essential domain groups and to assign each its default RID. </p></div><p> <a class="indexterm" name="id361123"></a> <a class="indexterm" name="id361130"></a> It is permissible to create any domain group that may be necessary; just make certain that the essential domain groups (well known) have been created and assigned their default RIDs. Other groups you create may be assigned any arbitrary RID you care to use. </p><p> Be sure to map each domain group to a UNIX system group. That is the only way to ensure that the group will be available for use as an NT domain group. </p><p> </p><div class="table"><a name="WKURIDS"></a><p class="title"><b>Table 12.1. Well-Known User Default RIDs</b></p><div class="table-contents"><table summary="Well-Known User Default RIDs" border="1"><colgroup><col align="left"><col align="left"><col align="left"><col align="center"></colgroup><thead><tr><th align="left">Well-Known Entity</th><th align="left">RID</th><th align="left">Type</th><th align="center">Essential</th></tr></thead><tbody><tr><td align="left">Domain Administrator</td><td align="left">500</td><td align="left">User</td><td align="center">No</td></tr><tr><td align="left">Domain Guest</td><td align="left">501</td><td align="left">User</td><td align="center">No</td></tr><tr><td align="left">Domain KRBTGT</td><td align="left">502</td><td align="left">User</td><td align="center">No</td></tr><tr><td align="left">Domain Admins</td><td align="left">512</td><td align="left">Group</td><td align="center">Yes</td></tr><tr><td align="left">Domain Users</td><td align="left">513</td><td align="left">Group</td><td align="center">Yes</td></tr><tr><td align="left">Domain Guests</td><td align="left">514</td><td align="left">Group</td><td align="center">Yes</td></tr><tr><td align="left">Domain Computers</td><td align="left">515</td><td align="left">Group</td><td align="center">No</td></tr><tr><td align="left">Domain Controllers</td><td align="left">516</td><td align="left">Group</td><td align="center">No</td></tr><tr><td align="left">Domain Certificate Admins</td><td align="left">517</td><td align="left">Group</td><td align="center">No</td></tr><tr><td align="left">Domain Schema Admins</td><td align="left">518</td><td align="left">Group</td><td align="center">No</td></tr><tr><td align="left">Domain Enterprise Admins</td><td align="left">519</td><td align="left">Group</td><td align="center">No</td></tr><tr><td align="left">Domain Policy Admins</td><td align="left">520</td><td align="left">Group</td><td align="center">No</td></tr><tr><td align="left">Builtin Admins</td><td align="left">544</td><td align="left">Alias</td><td align="center">No</td></tr><tr><td align="left">Builtin users</td><td align="left">545</td><td align="left">Alias</td><td align="center">No</td></tr><tr><td align="left">Builtin Guests</td><td align="left">546</td><td align="left">Alias</td><td align="center">No</td></tr><tr><td align="left">Builtin Power Users</td><td align="left">547</td><td align="left">Alias</td><td align="center">No</td></tr><tr><td align="left">Builtin Account Operators</td><td align="left">548</td><td align="left">Alias</td><td align="center">No</td></tr><tr><td align="left">Builtin System Operators</td><td align="left">549</td><td align="left">Alias</td><td align="center">No</td></tr><tr><td align="left">Builtin Print Operators</td><td align="left">550</td><td align="left">Alias</td><td align="center">No</td></tr><tr><td align="left">Builtin Backup Operators</td><td align="left">551</td><td align="left">Alias</td><td align="center">No</td></tr><tr><td align="left">Builtin Replicator</td><td align="left">552</td><td align="left">Alias</td><td align="center">No</td></tr><tr><td align="left">Builtin RAS Servers</td><td align="left">553</td><td align="left">Alias</td><td align="center">No</td></tr></tbody></table></div></div><p><br class="table-break"> </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id361575"></a>Example Configuration</h3></div></div></div><p> <a class="indexterm" name="id361583"></a> You can list the various groups in the mapping database by executing <code class="literal">net groupmap list</code>. Here is an example: </p><p> <a class="indexterm" name="id361605"></a> </p><pre class="screen"> <code class="prompt">root# </code> <strong class="userinput"><code>net groupmap list</code></strong> Domain Admins (S-1-5-21-2547222302-1596225915-2414751004-512) -> domadmin Domain Users (S-1-5-21-2547222302-1596225915-2414751004-513) -> domuser Domain Guests (S-1-5-21-2547222302-1596225915-2414751004-514) -> domguest </pre><p> </p><p> For complete details on <code class="literal">net groupmap</code>, refer to the net(8) man page. </p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id361647"></a>Configuration Scripts</h2></div></div></div><p> Everyone needs tools. Some of us like to create our own, others prefer to use canned tools (i.e., prepared by someone else for general use). </p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id361657"></a>Sample <code class="filename">smb.conf</code> Add Group Script</h3></div></div></div><p> <a class="indexterm" name="id361671"></a> <a class="indexterm" name="id361678"></a> <a class="indexterm" name="id361684"></a> <a class="indexterm" name="id361691"></a> <a class="indexterm" name="id361698"></a> A script to create complying group names for use by the Samba group interfaces is provided in <a href="groupmapping.html#smbgrpadd.sh" title="Example 12.1. smbgrpadd.sh">smbgrpadd.sh</a>. This script adds a temporary entry in the <code class="filename">/etc/group</code> file and then renames it to the desired name. This is an example of a method to get around operating system maintenance tool limitations such as those present in some version of the <code class="literal">groupadd</code> tool. </p><div class="example"><a name="smbgrpadd.sh"></a><p class="title"><b>Example 12.1. smbgrpadd.sh</b></p><div class="example-contents"><pre class="programlisting"> #!/bin/bash # Add the group using normal system groupadd tool. groupadd smbtmpgrp00 thegid=`cat /etc/group | grep ^smbtmpgrp00 | cut -d ":" -f3` # Now change the name to what we want for the MS Windows networking end cp /etc/group /etc/group.bak cat /etc/group.bak | sed "s/^smbtmpgrp00/$1/g" > /etc/group rm /etc/group.bak # Now return the GID as would normally happen. echo $thegid exit 0 </pre></div></div><p><br class="example-break"> </p><p> The <code class="filename">smb.conf</code> entry for the above script shown in <a href="groupmapping.html#smbgrpadd" title="Example 12.2. Configuration of smb.conf for the add group Script">the configuration of <code class="filename">smb.conf</code> for the add group Script</a> demonstrates how it may be used. </p><div class="example"><a name="smbgrpadd"></a><p class="title"><b>Example 12.2. Configuration of <code class="filename">smb.conf</code> for the add group Script</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="id361802"></a><em class="parameter"><code>add group script = /path_to_tool/smbgrpadd.sh "%g"</code></em></td></tr></table></div></div><p><br class="example-break"> </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id361818"></a>Script to Configure Group Mapping</h3></div></div></div><p> <a class="indexterm" name="id361826"></a> In our example we have created a UNIX/Linux group called <code class="literal">ntadmin</code>. Our script will create the additional groups <code class="literal">Orks</code>, <code class="literal">Elves</code>, and <code class="literal">Gnomes</code>. It is a good idea to save this shell script for later use just in case you ever need to rebuild your mapping database. For the sake of convenience we elect to save this script as a file called <code class="filename">initGroups.sh</code>. This script is given in <a href="groupmapping.html#set-group-map" title="Example 12.3. Script to Set Group Mapping">intGroups.sh</a>. <a class="indexterm" name="id361873"></a> </p><div class="example"><a name="set-group-map"></a><p class="title"><b>Example 12.3. Script to Set Group Mapping</b></p><div class="example-contents"><pre class="programlisting"> #!/bin/bash net groupmap add ntgroup="Domain Admins" unixgroup=ntadmin rid=512 type=d net groupmap add ntgroup="Domain Users" unixgroup=users rid=513 type=d net groupmap add ntgroup="Domain Guests" unixgroup=nobody rid=514 type=d groupadd Orks groupadd Elves groupadd Gnomes net groupmap add ntgroup="Orks" unixgroup=Orks type=d net groupmap add ntgroup="Elves" unixgroup=Elves type=d net groupmap add ntgroup="Gnomes" unixgroup=Gnomes type=d </pre></div></div><p><br class="example-break"> </p><p> Of course it is expected that the administrator will modify this to suit local needs. For information regarding the use of the <code class="literal">net groupmap</code> tool please refer to the man page. </p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p> Versions of Samba-3 prior to 3.0.23 automatically create default group mapping for the <code class="literal">Domain Admins, Domain Users</code> and <code class="literal">Domain Guests</code> Windows groups, but do not map them to UNIX GIDs. This was a cause of administrative confusion and trouble. Commencing with Samba-3.0.23 this annomaly has been fixed - thus all Windows groups must now be manually and explicitly created and mapped to a valid UNIX GID by the Samba administrator. </p></div></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id361932"></a>Common Errors</h2></div></div></div><p> At this time there are many little surprises for the unwary administrator. In a real sense it is imperative that every step of automated control scripts be carefully tested manually before putting it into active service. </p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id361943"></a>Adding Groups Fails</h3></div></div></div><p> <a class="indexterm" name="id361951"></a> This is a common problem when the <code class="literal">groupadd</code> is called directly by the Samba interface script for the <a class="indexterm" name="id361964"></a>add group script in the <code class="filename">smb.conf</code> file. </p><p> <a class="indexterm" name="id361981"></a> <a class="indexterm" name="id361988"></a> The most common cause of failure is an attempt to add an MS Windows group account that has an uppercase character and/or a space character in it. </p><p> <a class="indexterm" name="id361999"></a> There are three possible workarounds. First, use only group names that comply with the limitations of the UNIX/Linux <code class="literal">groupadd</code> system tool. Second, it involves the use of the script mentioned earlier in this chapter, and third is the option is to manually create a UNIX/Linux group account that can substitute for the MS Windows group name, then use the procedure listed above to map that group to the MS Windows group. </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id362018"></a>Adding Domain Users to the Workstation Power Users Group</h3></div></div></div><p>“<span class="quote"> What must I do to add domain users to the Power Users group? </span>”</p><p> <a class="indexterm" name="id362031"></a> The Power Users group is a group that is local to each Windows 200x/XP Professional workstation. You cannot add the Domain Users group to the Power Users group automatically, it must be done on each workstation by logging in as the local workstation <span class="emphasis"><em>administrator</em></span> and then using the following procedure: </p><div class="procedure"><ol type="1"><li><p> Click <span class="guimenu">Start -> Control Panel -> Users and Passwords</span>. </p></li><li><p> Click the <span class="guimenuitem">Advanced</span> tab. </p></li><li><p> Click the <span class="guibutton">Advanced</span> button. </p></li><li><p> Click <code class="constant">Groups</code>. </p></li><li><p> Double-click <code class="constant">Power Users</code>. This will launch the panel to add users or groups to the local machine <code class="constant">Power Users</code> group. </p></li><li><p> Click the <span class="guibutton">Add</span> button. </p></li><li><p> Select the domain from which the <code class="constant">Domain Users</code> group is to be added. </p></li><li><p> Double-click the <code class="constant">Domain Users</code> group. </p></li><li><p> Click the <span class="guibutton">OK</span> button. If a logon box is presented during this process, please remember to enter the connect as <code class="constant">DOMAIN\UserName</code>, that is, for the domain <code class="constant">MIDEARTH</code> and the user <code class="constant">root</code> enter <code class="constant">MIDEARTH\root</code>. </p></li></ol></div></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="passdb.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="optional.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="NetCommand.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 11. Account Information Databases </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 13. Remote and Local Management: The Net Command</td></tr></table></div></body></html>