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diff --git a/docs/howto/PDC.xml b/docs/howto/PDC.xml new file mode 100644 index 0000000000..6d3fa64a24 --- /dev/null +++ b/docs/howto/PDC.xml @@ -0,0 +1,990 @@ +<chapter id="samba-pdc"> + +<chapterinfo> + &author.jht; + &author.jerry; + &author.dbannon; + <author>&person.gd; <contrib>LDAP updates</contrib></author> +</chapterinfo> + +<title>Domain Control</title> + +<para> +There are many who approach MS Windows networking with incredible misconceptions. +That's okay, because it gives the rest of us plenty of opportunity to be of assistance. +Those who really want help would be well advised to become familiar with information +that is already available. +</para> + +<para> +The reader is advised not to tackle this section without having first understood +and mastered some basics. MS Windows networking is not particularly forgiving of +mis-configuration. Users of MS Windows networking are likely to complain +of persistent niggles that may be caused by a broken network configuration. +To a great many people, however, MS Windows networking starts with a Domain Controller +that in some magical way is expected to solve all network operational ills. +</para> + +<para> +<link linkend="domain-example">The diagram</link> shows a typical MS Windows Domain Security +network environment. Workstations A, B and C are representative of many physical MS Windows +network clients. +</para> + +<figure id="domain-example"><title>An Example Domain.</title> +<mediaobject> +<imageobject role="latex"><imagedata fileref="projdoc/imagefiles/domain" width="4in" height="3in" scalefit="1"/></imageobject> +<imageobject><imagedata fileref="projdoc/imagefiles/domain.png" scale="50" scalefit="1"/></imageobject> +</mediaobject> +</figure> + + +<?latex \newpage ?> + +<para> +From the Samba mailing list one can readily identify many common networking issues. +If you are not clear on the following subjects, then it will do much good to read the +sections of this HOWTO that deal with it. These are the most common causes of MS Windows +networking problems: +</para> + +<itemizedlist> + <listitem><para>Basic TCP/IP configuration.</para></listitem> + <listitem><para>NetBIOS name resolution.</para></listitem> + <listitem><para>Authentication configuration.</para></listitem> + <listitem><para>User and group configuration.</para></listitem> + <listitem><para>Basic file and directory permission control in UNIX/Linux.</para></listitem> + <listitem><para>Understanding how MS Windows clients interoperate in a network + environment.</para></listitem> +</itemizedlist> + +<para> +Do not be put off; on the surface of it MS Windows networking seems so simple that anyone +can do it. In fact, it is not a good idea to set up an MS Windows network with +inadequate training and preparation. But let's get our first indelible principle out of the +way: <emphasis>It is perfectly okay to make mistakes!</emphasis> In the right place and at +the right time, mistakes are the essence of learning. It is very much not okay to make +mistakes that cause loss of productivity and impose an avoidable financial burden on an +organization. +</para> + +<para> +Where is the right place to make mistakes? Only out of harms way. If you are going to +make mistakes, then please do it on a test network, away from users and in such a way as +to not inflict pain on others. Do your learning on a test network. +</para> + +<sect1> +<title>Features and Benefits</title> + +<para> +<indexterm><primary>domain security</primary></indexterm> +<emphasis>What is the key benefit of Microsoft Domain Security?</emphasis> +</para> + +<para> +In a word, <emphasis>Single Sign On</emphasis>, or SSO for short. To many, this is the Holy +Grail of MS Windows NT and beyond networking. SSO allows users in a well-designed network +to log onto any workstation that is a member of the domain that their user account is in +(or in a domain that has an appropriate trust relationship with the domain they are visiting) +and they will be able to log onto the network and access resources (shares, files and printers) +as if they are sitting at their home (personal) workstation. This is a feature of the Domain +Security protocols. +</para> + +<para> +<indexterm><primary>SID</primary></indexterm> +The benefits of Domain Security are available to those sites that deploy a Samba PDC. +A Domain provides a unique network security identifier (SID). Domain user and group security +identifiers are comprised of the network SID plus a relative identifier (RID) that is unique to +the account. User and Group SIDs (the network SID plus the RID) can be used to create Access Control +Lists (ACLs) attached to network resources to provide organizational access control. UNIX systems +recognize only local security identifiers. +</para> + +<note><para> +Network clients of an MS Windows Domain Security Environment must be Domain Members to be +able to gain access to the advanced features provided. Domain Membership involves more than just +setting the workgroup name to the Domain name. It requires the creation of a Domain trust account +for the workstation (called a machine account). Refer to <link linkend="domain-member">Domain Membership</link> +for more information. +</para></note> + +<para> +The following functionalities are new to the Samba-3 release: +</para> + +<itemizedlist> + <listitem><para> + Windows NT4 domain trusts. + </para></listitem> + + <listitem><para> + <indexterm><primary>Nexus.exe</primary></indexterm> + Adding users via the User Manager for Domains. This can be done on any MS Windows + client using the <filename>Nexus.exe</filename> toolkit for Windows 9x/Me, or using + the SRVTOOLS.EXE package for MS Windows NT4/200x/XP platforms. These packages are + available from Microsoft's Web site. + </para></listitem> + + <listitem><para> + Introduces replaceable and multiple user account (authentication) + backends. In the case where the backend is placed in an LDAP database, + Samba-3 confers the benefits of a backend that can be distributed, replicated + and is highly scalable. + </para></listitem> + + <listitem><para> + Implements full Unicode support. This simplifies cross locale internationalization + support. It also opens up the use of protocols that Samba-2.2.x had but could not use due + to the need to fully support Unicode. + </para></listitem> +</itemizedlist> + +<para> +The following functionalities are not provided by Samba-3: +</para> +<itemizedlist> + <listitem><para> +<indexterm><primary>SAM</primary></indexterm> +<indexterm><primary>replication</primary></indexterm> + SAM replication with Windows NT4 Domain Controllers + (i.e., a Samba PDC and a Windows NT BDC or vice versa). This means Samba + cannot operate as a BDC when the PDC is Microsoft-based or + replicate account data to Windows BDCs. + </para></listitem> + + <listitem><para> + Acting as a Windows 2000 Domain Controller (i.e., Kerberos and + Active Directory). In point of fact, Samba-3 does have some + Active Directory Domain Control ability that is at this time + purely experimental that is certain to change as it becomes a + fully supported feature some time during the Samba-3 (or later) + life cycle. However, Active Directory is more then just SMB &smbmdash; + it's also LDAP, Kerberos, DHCP, and other protocols (with proprietary + extensions, of course). + </para></listitem> + + <listitem><para> + The Windows 200x/XP MMC (Computer Management) Console can not be used + to manage a Samba-3 server. For this you can use only the MS Windows NT4 + Domain Server manager and the MS Windows NT4 Domain User Manager. Both are + part of the SVRTOOLS.EXE package mentioned later. + </para></listitem> +</itemizedlist> + +<para> +Windows 9x/Me/XP Home clients are not true members of a domain for reasons outlined +in this chapter. The protocol for support of Windows 9x/Me style network (domain) logons +is completely different from NT4/Windows 200x type domain logons and has been officially supported +for some time. These clients use the old LanMan Network Logon facilities that are supported +in Samba since approximately the Samba-1.9.15 series. +</para> + +<para> +Samba-3 implements group mapping between Windows NT groups +and UNIX groups (this is really quite complicated to explain in a short space). This is +discussed more fully in <link linkend="groupmapping">Group Mapping &smbmdash; MS Windows and UNIX</link>. +</para> + +<para> +<indexterm><primary>Machine Trust Accounts</primary></indexterm> +Samba-3, like an MS Windows NT4 PDC or a Windows 200x Active Directory, needs to store +user and Machine Trust Account information in a suitable backend data-store. +Refer to <link linkend="machine-trust-accounts">MS Windows Workstation/Server Machine Trust Accounts</link>. With Samba-3 there can be multiple +backends for this. A complete discussion of account database backends can be found in +<link linkend="passdb">Account Information Databases</link>. +</para> + +</sect1> + +<sect1> +<title>Basics of Domain Control</title> + +<para> +Over the years, public perceptions of what Domain Control really is has taken on an +almost mystical nature. Before we branch into a brief overview of Domain Control, +there are three basic types of Domain Controllers. +</para> + +<sect2> +<title>Domain Controller Types</title> + +<itemizedlist> + <listitem><para>Primary Domain Controller</para></listitem> + <listitem><para>Backup Domain Controller</para></listitem> + <listitem><para>ADS Domain Controller</para></listitem> +</itemizedlist> + +<para> +The <emphasis>Primary Domain Controller</emphasis> or PDC plays an important role in MS +Windows NT4. In Windows 200x Domain Control architecture, this role is held by Domain Controllers. +Folklore dictates that because of its role in the MS Windows +network, the Domain Controller should be the most powerful and most capable machine in the network. +As strange as it may seem to say this here, good overall network performance dictates that +the entire infrastructure needs to be balanced. It is advisable to invest more in Stand-alone +(Domain Member) servers than in the Domain Controllers. +</para> + +<para> +<indexterm><primary>SAM</primary></indexterm> +In the case of MS Windows NT4-style domains, it is the PDC that initiates a new Domain Control database. +This forms a part of the Windows registry called the Security Account Manager (SAM). It plays a key +part in NT4-type domain user authentication and in synchronization of the domain authentication +database with Backup Domain Controllers. +</para> + +<para> +With MS Windows 200x Server-based Active Directory domains, one Domain Controller initiates a potential +hierarchy of Domain Controllers, each with their own area of delegated control. The master domain +controller has the ability to override any downstream controller, but a down-line controller has +control only over its down-line. With Samba-3, this functionality can be implemented using an +LDAP-based user and machine account backend. +</para> + +<para> +New to Samba-3 is the ability to use a backend database that holds the same type of data as +the NT4-style SAM database (one of the registry files)<footnote>See also <link linkend="passdb">Account Information Databases</link>.</footnote>. +</para> + +<para> +The <emphasis>Backup Domain Controller</emphasis> or BDC plays a key role in servicing network +authentication requests. The BDC is biased to answer logon requests in preference to the PDC. +On a network segment that has a BDC and a PDC, the BDC will most likely service network +logon requests. The PDC will answer network logon requests when the BDC is too busy (high load). +A BDC can be promoted to a PDC. If the PDC is online at the time that a BDC is promoted to +PDC, the previous PDC is automatically demoted to a BDC. With Samba-3, this is not an automatic +operation; the PDC and BDC must be manually configured and changes also need to be made. +</para> + +<para> +With MS Windows NT4, a decision is made at installation to determine what type of machine the server will be. +It is possible to promote a BDC to a PDC and vice versa. The only way +to convert a Domain Controller to a Domain Member server or a Stand-alone Server is to +reinstall it. The install time choices offered are: +</para> + +<itemizedlist> + <listitem><para><emphasis>Primary Domain Controller</emphasis> &smbmdash; the one that seeds the domain SAM.</para></listitem> + <listitem><para><emphasis>Backup Domain Controller</emphasis> &smbmdash; one that obtains a copy of the domain SAM.</para></listitem> + <listitem><para><emphasis>Domain Member Server</emphasis> &smbmdash; one that has no copy of the domain SAM, rather it obtains authentication from a Domain Controller for all access controls.</para></listitem> + <listitem><para><emphasis>Stand-alone Server</emphasis> &smbmdash; one that plays no part is SAM synchronization, has its own authentication database and plays no role in Domain Security.</para></listitem> +</itemizedlist> + +<para> +With MS Windows 2000, the configuration of Domain Control is done after the server has been +installed. Samba-3 is capable of acting fully as a native member of a Windows 200x server +Active Directory domain. +</para> + +<para> +<indexterm><primary>replication</primary><secondary>SAM</secondary></indexterm> +New to Samba-3 is the ability to function fully as an MS Windows NT4-style Domain Controller, +excluding the SAM replication components. However, please be aware that Samba-3 also supports the +MS Windows 200x Domain Control protocols. +</para> + +<para> +At this time any appearance that Samba-3 is capable of acting as an +<emphasis>Domain Controller</emphasis> in native ADS mode is limited and experimental in nature. +This functionality should not be used until the Samba Team offers formal support for it. +At such a time, the documentation will be revised to duly reflect all configuration and +management requirements. Samba can act as a NT4-style DC in a Windows 2000/XP +environment. However, there are certain compromises: + +<itemizedlist> + <listitem>No machine policy files.</listitem> + <listitem>No Group Policy Objects.</listitem> + <listitem>No synchronously executed AD logon scripts.</listitem> + <listitem>Can't use Active Directory management tools to manage users and machines.</listitem> + <listitem>Registry changes tattoo the main registry, while with AD they do not leave permanent changes in effect.</listitem> + <listitem>Without AD you cannot perform the function of exporting specific applications to specific users or groups.</listitem> +</itemizedlist> +</para> + +</sect2> + +<sect2> +<title>Preparing for Domain Control</title> + +<para> +There are two ways that MS Windows machines may interact with each other, with other servers +and with Domain Controllers: either as <emphasis>Stand-alone</emphasis> systems, more commonly +called <emphasis>Workgroup</emphasis> members, or as full participants in a security system, +more commonly called <emphasis>Domain</emphasis> members. +</para> + +<para> +It should be noted that <emphasis>Workgroup</emphasis> membership involves no special configuration +other than the machine being configured so the network configuration has a commonly used name +for its workgroup entry. It is not uncommon for the name WORKGROUP to be used for this. With this +mode of configuration, there are no Machine Trust Accounts and any concept of membership as such +is limited to the fact that all machines appear in the network neighborhood to be logically +grouped together. Again, just to be clear: <emphasis>workgroup mode does not involve security machine +accounts</emphasis>. +</para> + +<para> +Domain Member machines have a machine account in the Domain accounts database. A special procedure +must be followed on each machine to effect Domain Membership. This procedure, which can be done +only by the local machine Administrator account, will create the Domain machine account (if it does +not exist), and then initializes that account. When the client first logs onto the +Domain it triggers a machine password change. +</para> + +<note><para> +When Samba is configured as a Domain Controller, secure network operation demands that +all MS Windows NT4/200x/XP Professional clients should be configured as Domain Members. +If a machine is not made a member of the Domain, then it will operate like a workgroup +(Stand-alone) machine. Please refer to <link linkend="domain-member">Domain Membership</link> chapter for +information regarding Domain Membership. +</para></note> + +<para> +The following are necessary for configuring Samba-3 as an MS Windows NT4-style PDC for MS Windows +NT4/200x/XP clients: +</para> + +<itemizedlist> + <listitem><para>Configuration of basic TCP/IP and MS Windows networking.</para></listitem> + <listitem><para>Correct designation of the Server Role (<smbconfoption><name>security</name><value>user</value></smbconfoption>).</para></listitem> + <listitem><para>Consistent configuration of Name Resolution<footnote><para>See <link linkend="NetworkBrowsing">Network Browsing</link>, and + <link linkend="integrate-ms-networks">Integrating MS Windows Networks with Samba</link>.</para></footnote>.</para></listitem> + <listitem><para>Domain logons for Windows NT4/200x/XP Professional clients.</para></listitem> + <listitem><para>Configuration of Roaming Profiles or explicit configuration to force local profile usage.</para></listitem> + <listitem><para>Configuration of network/system policies.</para></listitem> + <listitem><para>Adding and managing domain user accounts.</para></listitem> + <listitem><para>Configuring MS Windows client machines to become Domain Members.</para></listitem> +</itemizedlist> + +<para> +The following provisions are required to serve MS Windows 9x/Me clients: +</para> + +<itemizedlist> + <listitem><para>Configuration of basic TCP/IP and MS Windows networking.</para></listitem> + <listitem><para>Correct designation of the server role (<smbconfoption><name>security</name><value>user</value></smbconfoption>).</para></listitem> + <listitem><para>Network Logon Configuration (since Windows 9x/Me/XP Home are not technically domain + members, they do not really participate in the security aspects of Domain logons as such).</para></listitem> + <listitem><para>Roaming Profile Configuration.</para></listitem> + <listitem><para>Configuration of System Policy handling.</para></listitem> + <listitem><para>Installation of the network driver <quote>Client for MS Windows Networks</quote> and configuration + to log onto the domain.</para></listitem> + <listitem><para>Placing Windows 9x/Me clients in User Level Security &smbmdash; if it is desired to allow + all client share access to be controlled according to domain user/group identities.</para></listitem> + <listitem><para>Adding and managing domain user accounts.</para></listitem> +</itemizedlist> + +<note><para> +Roaming Profiles and System/Network policies are advanced network administration topics +that are covered in the <link linkend="ProfileMgmt">Desktop Profile Management</link> and +<link linkend="PolicyMgmt">System and Account Policies</link> chapters of this document. However, these are not +necessarily specific to a Samba PDC as much as they are related to Windows NT networking concepts. +</para></note> + +<para> +A Domain Controller is an SMB/CIFS server that: +</para> + +<itemizedlist> + <listitem><para> + Registers and advertises itself as a Domain Controller (through NetBIOS broadcasts + as well as by way of name registrations either by Mailslot Broadcasts over UDP broadcast, + to a WINS server over UDP uni-cast, or via DNS and Active Directory). + </para></listitem> + + <listitem><para> + Provides the NETLOGON service. (This is actually a collection of services that runs over + multiple protocols. These include the LanMan Logon service, the Netlogon service, + the Local Security Account service, and variations of them.) + </para></listitem> + + <listitem><para> + Provides a share called NETLOGON. + </para></listitem> +</itemizedlist> + +<para> +It is rather easy to configure Samba to provide these. Each Samba Domain Controller must provide +the NETLOGON service that Samba calls the <smbconfoption><name>domain logons</name></smbconfoption> functionality +(after the name of the parameter in the &smb.conf; file). Additionally, one server in a Samba-3 +Domain must advertise itself as the Domain Master Browser<footnote>See <link linkend="NetworkBrowsing">Network Browsing</link>.</footnote>. +This causes the Primary Domain Controller to claim a domain-specific NetBIOS name that identifies it as a +Domain Master Browser for its given domain or workgroup. Local master browsers in the same domain or workgroup on +broadcast-isolated subnets then ask for a complete copy of the browse list for the whole wide area network. +Browser clients will then contact their Local Master Browser, and will receive the domain-wide browse list, +instead of just the list for their broadcast-isolated subnet. +</para> + +</sect2> +</sect1> + +<sect1> +<title>Domain Control &smbmdash; Example Configuration</title> + +<para> +The first step in creating a working Samba PDC is to understand the parameters necessary +in &smb.conf;. An example &smb.conf; for acting as a PDC can be found in <link linkend="pdc-example">the next example</link>. +</para> + +<para> +<smbconfexample id="pdc-example"> +<title>smb.conf for being a PDC</title> +<smbconfsection>[global]</smbconfsection> +<smbconfoption><name>netbios name</name><value><replaceable>BELERIAND</replaceable></value></smbconfoption> +<smbconfoption><name>workgroup</name><value><replaceable>&example.workgroup;</replaceable></value></smbconfoption> +<smbconfoption><name>passdb backend</name><value>tdbsam</value></smbconfoption> +<smbconfoption><name>os level</name><value>33</value></smbconfoption> +<smbconfoption><name>preferred master</name><value>yes</value></smbconfoption> +<smbconfoption><name>domain master</name><value>yes</value></smbconfoption> +<smbconfoption><name>local master</name><value>yes</value></smbconfoption> +<smbconfoption><name>security</name><value>user</value></smbconfoption> +<smbconfoption><name>domain logons</name><value>yes</value></smbconfoption> +<smbconfoption><name>logon path</name><value>\\%N\profiles\%u</value></smbconfoption> +<smbconfoption><name>logon drive</name><value>H:</value></smbconfoption> +<smbconfoption><name>logon home</name><value>\\homeserver\%u\winprofile</value></smbconfoption> +<smbconfoption><name>logon script</name><value>logon.cmd</value></smbconfoption> + +<smbconfsection>[netlogon]</smbconfsection> +<smbconfoption><name>path</name><value>/var/lib/samba/netlogon</value></smbconfoption> +<smbconfoption><name>read only</name><value>yes</value></smbconfoption> +<smbconfoption><name>write list</name><value><replaceable>ntadmin</replaceable></value></smbconfoption> + +<smbconfsection>[profiles]</smbconfsection> +<smbconfoption><name>path</name><value>/var/lib/samba/profiles</value></smbconfoption> +<smbconfoption><name>read only</name><value>no</value></smbconfoption> +<smbconfoption><name>create mask</name><value>0600</value></smbconfoption> +<smbconfoption><name>directory mask</name><value>0700</value></smbconfoption> +</smbconfexample> +</para> + +<para> +The basic options shown in <link linkend="pdc-example">this example</link> are explained as follows: +</para> + +<variablelist> + <varlistentry><term>passdb backend </term> + <listitem><para> + This contains all the user and group account information. Acceptable values for a PDC + are: <emphasis>smbpasswd, tdbsam, and ldapsam</emphasis>. The <quote>guest</quote> entry provides + default accounts and is included by default, there is no need to add it explicitly.</para> + + <para> + Where use of backup Domain Controllers (BDCs) is intended, the only logical choice is + to use LDAP so the passdb backend can be distributed. The tdbsam and smbpasswd files + cannot effectively be distributed and therefore should not be used. + </para></listitem> + </varlistentry> + <varlistentry><term>Domain Control Parameters </term> + <listitem><para> + The parameters <emphasis>os level, preferred master, domain master, security, + encrypt passwords, and domain logons</emphasis> play a central role in assuring domain + control and network logon support.</para> + + <para> + The <emphasis>os level</emphasis> must be set at or above a value of 32. A Domain Controller + must be the Domain Master Browser, must be set in <emphasis>user</emphasis> mode security, + must support Microsoft-compatible encrypted passwords, and must provide the network logon + service (domain logons). Encrypted passwords must be enabled. For more details on how + to do this, refer to <link linkend="passdb">Account Information Databases</link>. + </para></listitem> + </varlistentry> + <varlistentry><term>Environment Parameters </term> + <listitem><para> + The parameters <emphasis>logon path, logon home, logon drive, and logon script</emphasis> are + environment support settings that help to facilitate client logon operations and that help + to provide automated control facilities to ease network management overheads. Please refer + to the man page information for these parameters. + </para></listitem> + </varlistentry> + <varlistentry><term>NETLOGON Share </term> + <listitem><para> + The NETLOGON share plays a central role in domain logon and Domain Membership support. + This share is provided on all Microsoft Domain Controllers. It is used to provide logon + scripts, to store Group Policy files (NTConfig.POL), as well as to locate other common + tools that may be needed for logon processing. This is an essential share on a Domain Controller. + </para></listitem> + </varlistentry> + <varlistentry><term>PROFILE Share </term> + <listitem><para> + This share is used to store user desktop profiles. Each user must have a directory at the root + of this share. This directory must be write-enabled for the user and must be globally read-enabled. + Samba-3 has a VFS module called <quote>fake_permissions</quote> that may be installed on this share. This will + allow a Samba administrator to make the directory read-only to everyone. Of course this is useful + only after the profile has been properly created. + </para></listitem> + </varlistentry> +</variablelist> + +<note><para> +The above parameters make for a full set of parameters that may define the server's mode +of operation. The following &smb.conf; parameters are the essentials alone: +</para> + +<para> +<smbconfblock> +<smbconfoption><name>netbios name</name><value>BELERIAND</value></smbconfoption> +<smbconfoption><name>workgroup</name><value>&example.workgroup;</value></smbconfoption> +<smbconfoption><name>domain logons</name><value>Yes</value></smbconfoption> +<smbconfoption><name>domain master</name><value>Yes</value></smbconfoption> +<smbconfoption><name>security</name><value>User</value></smbconfoption> +</smbconfblock> +</para> + +<para> +The additional parameters shown in the longer listing above just makes for +a more complete explanation. +</para></note> + +</sect1> + +<sect1> +<title>Samba ADS Domain Control</title> + +<para> +Samba-3 is not, and cannot act as, an Active Directory Server. It cannot truly function as +an Active Directory Primary Domain Controller. The protocols for some of the functionality +of Active Directory Domain Controllers has been partially implemented on an experimental +only basis. Please do not expect Samba-3 to support these protocols. Do not depend +on any such functionality either now or in the future. The Samba Team may remove these +experimental features or may change their behavior. This is mentioned for the benefit of those +who have discovered secret capabilities in Samba-3 and who have asked when this functionality will be +completed. The answer is maybe or maybe never! +</para> + +<para> +To be sure, Samba-3 is designed to provide most of the functionality that Microsoft Windows NT4-style +Domain Controllers have. Samba-3 does not have all the capabilities of Windows NT4, but it does have +a number of features that Windows NT4 domain controllers do not have. In short, Samba-3 is not NT4 and it +is not Windows Server 200x, it is not an Active Directory server. We hope this is plain and simple +enough for all to understand. +</para> + +</sect1> + +<sect1> +<title>Domain and Network Logon Configuration</title> + +<para> +The subject of Network or Domain Logons is discussed here because it forms +an integral part of the essential functionality that is provided by a Domain Controller. +</para> + +<sect2> +<title>Domain Network Logon Service</title> + +<para> +All Domain Controllers must run the netlogon service (<emphasis>domain logons</emphasis> +in Samba). One Domain Controller must be configured with <smbconfoption><name>domain master</name><value>Yes</value></smbconfoption> +(the Primary Domain Controller); on all Backup Domain Controllers <smbconfoption><name>domain master</name><value>No</value></smbconfoption> +must be set. +</para> + +<sect3> +<title>Example Configuration</title> + +<smbconfexample id="PDC-config"> +<title>smb.conf for being a PDC</title> +<smbconfsection>[global]</smbconfsection> +<smbconfoption><name>domain logons</name><value>Yes</value></smbconfoption> +<smbconfoption><name>domain master</name><value>(Yes on PDC, No on BDCs)</value></smbconfoption> + +<smbconfsection>[netlogon]</smbconfsection> +<smbconfoption><name>comment</name><value>Network Logon Service</value></smbconfoption> +<smbconfoption><name>path</name><value>/var/lib/samba/netlogon</value></smbconfoption> +<smbconfoption><name>guest ok</name><value>Yes</value></smbconfoption> +<smbconfoption><name>browseable</name><value>No</value></smbconfoption> +</smbconfexample> + +</sect3> +<sect3> +<title>The Special Case of MS Windows XP Home Edition</title> + +<para> +To be completely clear: If you want MS Windows XP Home Edition to integrate with your +MS Windows NT4 or Active Directory Domain Security, understand it cannot be done. +The only option is to purchase the upgrade from MS Windows XP Home Edition to +MS Windows XP Professional. +</para> + +<note><para> +MS Windows XP Home Edition does not have the ability to join any type of Domain +Security facility. Unlike MS Windows 9x/Me, MS Windows XP Home Edition also completely +lacks the ability to log onto a network. +</para></note> + +<para> +Now that this has been said, please do not ask the mailing list or email any of the +Samba Team members with your questions asking how to make this work. It can't be done. +If it can be done, then to do so would violate your software license agreement with +Microsoft, and we recommend that you do not do that. +</para> + +</sect3> + +<sect3> +<title>The Special Case of Windows 9x/Me</title> + +<para> +A domain and a workgroup are exactly the same in terms of network +browsing. The difference is that a distributable authentication +database is associated with a domain, for secure login access to a +network. Also, different access rights can be granted to users if they +successfully authenticate against a domain logon server. Samba-3 does this +now in the same way as MS Windows NT/200x. +</para> + +<para> +The SMB client logging on to a domain has an expectation that every other +server in the domain should accept the same authentication information. +Network browsing functionality of domains and workgroups is identical and +is explained in this documentation under the browsing discussions. +It should be noted that browsing is totally orthogonal to logon support. +</para> + +<para> +Issues related to the single-logon network model are discussed in this +section. Samba supports domain logons, network logon scripts and user +profiles for MS Windows for workgroups and MS Windows 9X/ME clients, +which are the focus of this section. +</para> + +<para> +When an SMB client in a domain wishes to logon, it broadcasts requests for a +logon server. The first one to reply gets the job, and validates its +password using whatever mechanism the Samba administrator has installed. +It is possible (but ill advised ) to create a domain where the user +database is not shared between servers, i.e., they are effectively workgroup +servers advertising themselves as participating in a domain. This +demonstrates how authentication is quite different from but closely +involved with domains. +</para> + +<para> +Using these features you can make your clients verify their logon via +the Samba server; make clients run a batch file when they logon to +the network and download their preferences, desktop and start menu. +</para> + +<para><emphasis> +MS Windows XP Home edition is not able to join a domain and does not permit +the use of domain logons. +</emphasis></para> + +<para> +Before launching into the configuration instructions, it is +worthwhile to look at how a Windows 9x/Me client performs a logon: +</para> + +<orderedlist> +<listitem> + <para> + The client broadcasts (to the IP broadcast address of the subnet it is in) + a NetLogon request. This is sent to the NetBIOS name DOMAIN<#1c> at the + NetBIOS layer. The client chooses the first response it receives, which + contains the NetBIOS name of the logon server to use in the format of + <filename>\\SERVER</filename>. + </para> +</listitem> + +<listitem> + <para> + The client connects to that server, logs on (does an SMBsessetupX) and + then connects to the IPC$ share (using an SMBtconX). + </para> +</listitem> + +<listitem> + <para> + The client does a NetWkstaUserLogon request, which retrieves the name + of the user's logon script. + </para> +</listitem> + +<listitem> + <para> + The client then connects to the NetLogon share and searches for said script. + If it is found and can be read, it is retrieved and executed by the client. + After this, the client disconnects from the NetLogon share. + </para> +</listitem> + +<listitem> + <para> + The client sends a NetUserGetInfo request to the server to retrieve + the user's home share, which is used to search for profiles. Since the + response to the NetUserGetInfo request does not contain much more than + the user's home share, profiles for Windows 9x clients must reside in the user + home directory. + </para> +</listitem> + +<listitem> + <para> + The client connects to the user's home share and searches for the + user's profile. As it turns out, you can specify the user's home share as + a share name and path. For example, <filename>\\server\fred\.winprofile</filename>. + If the profiles are found, they are implemented. + </para> +</listitem> + +<listitem> + <para> + The client then disconnects from the user's home share and reconnects to + the NetLogon share and looks for <filename>CONFIG.POL</filename>, the policies file. If this is + found, it is read and implemented. + </para> +</listitem> +</orderedlist> + +<para> +The main difference between a PDC and a Windows 9x/Me logon server configuration is: +</para> + +<itemizedlist> +<listitem><para> + Password encryption is not required for a Windows 9x/Me logon server. But note + that beginning with MS Windows 98 the default setting is that plain-text + password support is disabled. It can be re-enabled with the registry + changes that are documented in <link linkend="PolicyMgmt">System and Account Policies</link>. + </para></listitem> + + <listitem><para> + Windows 9x/Me clients do not require and do not use Machine Trust Accounts. + </para></listitem> +</itemizedlist> + +<para> +A Samba PDC will act as a Windows 9x/Me logon server; after all, it does provide the +network logon services that MS Windows 9x/Me expect to find. +</para> + +<note><para> +Use of plain-text passwords is strongly discouraged. Where used they are easily detected +using a sniffer tool to examine network traffic. +</para></note> + +</sect3> +</sect2> + +<sect2> +<title>Security Mode and Master Browsers</title> + +<para> +There are a few comments to make in order to tie up some loose ends. There has been +much debate over the issue of whether it is okay to configure Samba as a Domain +Controller in security modes other than user. The only security mode that will +not work due to technical reasons is share-mode security. Domain and server mode +security are really just a variation on SMB User Level Security. +</para> + +<para> +Actually, this issue is also closely tied to the debate on whether +Samba must be the Domain Master Browser for its workgroup +when operating as a DC. While it may technically be possible +to configure a server as such (after all, browsing and domain logons +are two distinctly different functions), it is not a good idea to do +so. You should remember that the DC must register the DOMAIN<#1b> NetBIOS +name. This is the name used by Windows clients to locate the DC. +Windows clients do not distinguish between the DC and the DMB. +A DMB is a Domain Master Browser &smbmdash; see <link linkend="DMB">Configuring WORKGROUP Browsing</link> section. +For this reason, it is wise to configure the Samba DC as the DMB. +</para> + +<para> +Now back to the issue of configuring a Samba DC to use a mode other than +<smbconfoption><name>security</name><value>user</value></smbconfoption>. If a Samba host is +configured to use another SMB server or DC in order to validate user connection requests, +it is a fact that some other machine on the network (the <smbconfoption><name>password server</name></smbconfoption>) +knows more about the user than the Samba host. About 99% of the time, this other host is +a Domain Controller. Now to operate in domain mode security, the <smbconfoption><name>workgroup</name></smbconfoption> +parameter must be set to the name of the Windows NT domain (which already has a Domain Controller). +If the domain does not already have a Domain Controller, you do not yet have a Domain. +</para> + +<para> +Configuring a Samba box as a DC for a domain that already by definition has a +PDC is asking for trouble. Therefore, you should always configure the Samba DC +to be the DMB for its domain and set <smbconfoption><name>security</name><value>user</value></smbconfoption>. +This is the only officially supported mode of operation. +</para> + +</sect2> + +</sect1> + +<sect1> +<title>Common Errors</title> + +<sect2> + <title><quote>$</quote> Cannot Be Included in Machine Name</title> +<para> +A machine account, typically stored in <filename>/etc/passwd</filename>, takes the form of the machine +name with a <quote>$</quote> appended. FreeBSD (and other BSD systems) will not create a user with a +<quote>$</quote> in the name. +</para> + +<para> +The problem is only in the program used to make the entry. Once made, it works perfectly. +Create a user without the <quote>$</quote>. Then use <command>vipw</command> to edit the entry, adding +the <quote>$</quote>. Or create the whole entry with vipw if you like; make sure you use a unique user login ID. +</para> + +<para><note>The machine account must have the exact name that the workstation has.</note></para> + +<note><para> +The UNIX tool <command>vipw</command> is a common tool for directly editing the <filename>/etc/passwd</filename> file. +</para></note> + +</sect2> + +<sect2> +<title>Joining Domain Fails Because of Existing Machine Account</title> + +<para> +<quote>I get told, `You already have a connection to the Domain....' or `Cannot join domain, the +credentials supplied conflict with an existing set...' when creating a Machine Trust Account.</quote> +</para> + +<para> +This happens if you try to create a Machine Trust Account from the machine itself and already have a +connection (e.g., mapped drive) to a share (or IPC$) on the Samba PDC. The following command +will remove all network drive connections: +<screen> +&dosprompt;<userinput>net use * /d</userinput> +</screen> +</para> + +<para> +Further, if the machine is already a <quote>member of a workgroup</quote> that +is the same name as the domain you are joining (bad idea) you will +get this message. Change the workgroup name to something else, it +does not matter what, reboot, and try again. +</para> +</sect2> + +<sect2> +<title>The System Cannot Log You On (C000019B)</title> + +<para><quote>I joined the domain successfully but after upgrading +to a newer version of the Samba code I get the message, <errorname>`The system +cannot log you on (C000019B), Please try again or consult your +system administrator</errorname> when attempting to logon.'</quote> +</para> + +<para> +<indexterm><primary>SID</primary></indexterm> +This occurs when the domain SID stored in the secrets.tdb database +is changed. The most common cause of a change in domain SID is when +the domain name and/or the server name (NetBIOS name) is changed. +The only way to correct the problem is to restore the original domain +SID or remove the domain client from the domain and rejoin. The domain +SID may be reset using either the net or rpcclient utilities. +</para> + +<para> +To reset or change the domain SID you can use the net command as follows: + +<screen> +&rootprompt;<userinput>net getlocalsid 'OLDNAME'</userinput> +&rootprompt;<userinput>net setlocalsid 'SID'</userinput> +</screen> +</para> + +<para> +Workstation Machine Trust Accounts work only with the Domain (or network) SID. If this SID changes +Domain Members (workstations) will not be able to log onto the domain. The original Domain SID +can be recovered from the secrets.tdb file. The alternative is to visit each workstation to re-join +it to the domain. +</para> + +</sect2> + +<sect2> +<title>The Machine Trust Account Is Not Accessible</title> + +<para> +<quote>When I try to join the domain I get the message, <errorname>`The machine account +for this computer either does not exist or is not accessible'</errorname>. What's +wrong?</quote> +</para> + +<para> +This problem is caused by the PDC not having a suitable Machine Trust Account. +If you are using the <smbconfoption><name>add machine script</name></smbconfoption> method to create +accounts then this would indicate that it has not worked. Ensure the domain +admin user system is working. +</para> + +<para> +Alternately, if you are creating account entries manually then they +have not been created correctly. Make sure that you have the entry +correct for the Machine Trust Account in <filename>smbpasswd</filename> file on the Samba PDC. +If you added the account using an editor rather than using the smbpasswd +utility, make sure that the account name is the machine NetBIOS name +with a <quote>$</quote> appended to it (i.e., computer_name$). There must be an entry +in both /etc/passwd and the smbpasswd file. +</para> + +<para> +Some people have also reported that inconsistent subnet masks between the Samba server and the NT +client can cause this problem. Make sure that these are consistent for both client and server. +</para> +</sect2> + +<sect2> +<title>Account Disabled</title> + +<para><quote>When I attempt to login to a Samba Domain from a NT4/W200x workstation, +I get a message about my account being disabled.</quote></para> + +<para> +Enable the user accounts with <userinput>smbpasswd -e <replaceable>username</replaceable> +</userinput>. This is normally done as an account is created. +</para> + +</sect2> + +<sect2> +<title>Domain Controller Unavailable</title> + +<para><quote>Until a few minutes after Samba has started, clients get the error `Domain Controller Unavailable'</quote></para> + +<para> +A Domain Controller has to announce its role on the network. This usually takes a while. Be patient for up to fifteen minutes, +then try again. +</para> +</sect2> + +<sect2> +<title>Cannot Log onto Domain Member Workstation After Joining Domain</title> + +<para> +<indexterm><primary>schannel</primary></indexterm> +<indexterm><primary>signing</primary></indexterm> +After successfully joining the domain, user logons fail with one of two messages: one to the +effect that the Domain Controller cannot be found; the other claims that the account does not +exist in the domain or that the password is incorrect. This may be due to incompatible +settings between the Windows client and the Samba-3 server for <emphasis>schannel</emphasis> +(secure channel) settings or <emphasis>smb signing</emphasis> settings. Check your Samba +settings for <emphasis> client schannel, server schannel, client signing, server signing</emphasis> +by executing: +<screen> +<command>testparm -v | more</command> and looking for the value of these parameters. +</screen> +</para> + +<para> +Also use the Microsoft Management Console &smbmdash; Local Security Settings. This tool is available from the +Control Panel. The Policy settings are found in the Local Policies/Security Options area and are prefixed by +<emphasis>Secure Channel: ..., and Digitally sign ....</emphasis>. +</para> + +<para> +It is important that these be set consistently with the Samba-3 server settings. +</para> + +</sect2> + +</sect1> +</chapter> |