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diff --git a/docs/guide/Chap09-AddingUNIXClients.xml b/docs/guide/Chap09-AddingUNIXClients.xml new file mode 100644 index 0000000000..379e4e2f37 --- /dev/null +++ b/docs/guide/Chap09-AddingUNIXClients.xml @@ -0,0 +1,2505 @@ +<?xml version="1.0" encoding="iso-8859-1"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [ + + <!-- Stuff for xincludes --> + <!ENTITY % xinclude SYSTEM "../entities/xinclude.dtd"> + %xinclude; + + <!-- entities files to use --> + <!ENTITY % global_entities SYSTEM '../entities/global.entities'> + %global_entities; + +]> + +<chapter id="unixclients"> + <title>Adding UNIX/LINUX Servers and Clients</title> + + <para><indexterm> + <primary>Open Magazine</primary> + </indexterm><indexterm> + <primary>survey</primary> + </indexterm> + The most frequently discussed Samba subjects over the past two years have focused around Domain Control and printing. + It is well known that Samba is a file and print server. A recent survey conducted by Open Magazine found + that of all respondents: 97% use Samba for file and print services, and 68% use Samba for Domain Control. See the + <ulink url="http://www.open-mag.com/cgi-bin/opencgi/surveys/survey.cgi?survey_name=samba">Open-Mag</ulink> + Web site for current information. The survey results as found on January 14, 2004, as shown in + <link linkend="ch09openmag"/>. + </para> + +<figure id="ch09openmag"> + <title>Open Magazine Samba Survey</title> + <mediaobject> + <imageobject role="latex"> + <imagedata fileref="guide/images/openmag.png" scale="60" scalefit="1"/> + </imageobject> + <imageobject> + <imagedata fileref="guide/images/openmag.png" scale="60" scalefit="1"/> + </imageobject> + </mediaobject> +</figure> + + <para> + While Domain Control is an exciting subject, basic file and print sharing remains the staple bread-and-butter + function that Samba provides. Yet this book may give the appearance of having focused too much on more + exciting aspects of Samba deployment. This chapter directs your attention to provide important information on + the addition of Samba servers into your present Windows network &smbmdash; whatever the controlling technology + may be. So let's get back to Abmas and our good friends Bob Jordan and company. + </para> + +<sect1> + <title>Introduction</title> + + <para><indexterm> + <primary>Linux desktop</primary> + </indexterm><indexterm> + <primary>Domain Member</primary> + <secondary>server</secondary> + </indexterm> + Bob Jordan looks back over the achievements of the past year or two. Daily events are rather straightforward + with not too many distractions or problems. Bob, your team is doing well, but a number of employees + are asking for Linux desktop systems. Your network has grown and demands additional Domain Member servers. Let's + get on with this; Christine and Stan are ready to go. + </para> + + <para><indexterm> + <primary>Domain Member</primary> + <secondary>desktop</secondary> + </indexterm> + Stan Soroka is firmly in control of the Department of the Future, while Christine is enjoying a stable and + predictable network environment. It is time to add more servers and to add Linux desktops. It is + time to meet the demands of future growth and endure trial by fire. Go on, walk the steps + with Stan and Company. + </para> + + <sect2> + <title>Assignment Tasks</title> + + <para><indexterm> + <primary>Active Directory</primary> + </indexterm> + You must now add UNIX/Linux Domain Member servers to your network. You have a friend who has a Windows 2003 + Active Directory Domain network who wants to add a Samba/Linux server and has asked Christine to help him + out. Your real objective is to help Christine to see more of the way the Microsoft world lives and use + her help to get validation that Samba really does live up to expectations. + </para> + + <para> + Over the past six months, you have hired several new staff who want Linux on their desktops. You must integrate + these systems to make sure that Abmas is not building islands of technology. You ask Christine to + do likewise at Swodniw Biz NL (your friend's company) to help them to evaluate a Linux desktop. You want to make + the right decision, don't you? + </para> + + </sect2> +</sect1> + +<sect1> + <title>Dissection and Discussion</title> + + <para><indexterm> + <primary>winbind</primary> + </indexterm> + Recent Samba mailing list activity is witness to how many sites are using winbind. Some have no trouble + at all with it, yet to others the problems seem insurmountable. Periodically there are complaints concerning + an inability to achieve identical user and group IDs between Windows and UNIX environments. + </para> + + <para> + You provide step-by-step implementations of the various tools that can be used for identity + resolution. You also provide working examples of solutions for integrated authentication for + both UNIX/Linux and Windows environments. + </para> + + <sect2> + <title>Technical Issues</title> + + <para> + One of the great challenges we face when people ask us, <quote>What is the best way to solve + this problem?</quote> is to get beyond the facts so we can not only clearly comprehend + the immediate technical problem, but also understand how needs may change. + </para> + + <para><indexterm> + <primary>integrate</primary> + </indexterm> + There are a few facts we should note when dealing with the question of how best to + integrate UNIX/Linux clients and servers into a Windows networking environment: + </para> + + <itemizedlist> + <listitem><para><indexterm> + <primary>Domain Controller</primary> + </indexterm><indexterm> + <primary>authoritative</primary> + </indexterm><indexterm> + <primary>accounts</primary> + <secondary>authoritative</secondary> + </indexterm><indexterm> + <primary>PDC</primary> + </indexterm><indexterm> + <primary>BDC</primary> + </indexterm> + A Domain Controller (PDC or BDC) is always authoritative for all accounts in its Domain. + This means that a BDC must (of necessity) be able to resolve all account UIDs and GIDs + to the same values that the PDC resolved them to. + </para></listitem> + + <listitem><para><indexterm> + <primary>local accounts</primary> + </indexterm><indexterm> + <primary>Domain Member</primary> + <secondary>authoritative</secondary> + <tertiary>local accounts</tertiary> + </indexterm><indexterm> + <primary>Domain accounts</primary> + </indexterm><indexterm> + <primary>winbindd</primary> + </indexterm> + A Domain Member can be authoritative for local accounts, but is never authoritative for + Domain accounts. If a user is accessing a Domain Member server and that user's account + is not known locally, the Domain Member server must resolve the identity of that user + from the Domain in which that user's account resides. It must then map that ID to a + UID/GID pair that it can use locally. This is handled by <command>winbindd</command>. + </para></listitem> + + <listitem><para> + Samba, when running on a Domain Member server, can resolve user identities from a + number of sources: + + <itemizedlist> + <listitem><para><indexterm> + <primary>getpwnam</primary> + </indexterm><indexterm> + <primary>getgrnam</primary> + </indexterm><indexterm> + <primary>NSS</primary> + </indexterm><indexterm> + <primary>LDAP</primary> + </indexterm><indexterm> + <primary>NIS</primary> + </indexterm> + By executing a system <command>getpwnam()</command> or <command>getgrnam()</command> call. + On systems that support it, this utilizes the name service switch (NSS) facility to + resolve names according to the configuration of the <filename>/etc/nsswitch.conf</filename> + file. NSS can be configured to use LDAP, winbind, NIS, or local files. + </para></listitem> + + <listitem><para><indexterm> + <primary>passdb backend</primary> + </indexterm><indexterm> + <primary>PADL</primary> + </indexterm><indexterm> + <primary>nss_ldap</primary> + </indexterm> + Performing, via NSS, a direct LDAP search (where an LDAP passdb backend has been configured). + This requires the use of the PADL nss_ldap tool (or equivalent). + </para></listitem> + + <listitem><para><indexterm> + <primary>winbindd</primary> + </indexterm><indexterm> + <primary>SID</primary> + </indexterm><indexterm> + <primary>winbindd_idmap.tdb</primary> + </indexterm><indexterm> + <primary>winbindd_cache.tdb</primary> + </indexterm> + Directly by querying <command>winbindd</command>. The <command>winbindd</command> + contact a Domain Controller to attempt to resolve the identity of the user or group. It + receives the Windows networking security identifier (SID) for that appropriate + account and then allocates a local UID or GID from the range of available IDs and + creates an entry in its <filename>winbindd_idmap.tdb</filename> and + <filename>winbindd_cache.tdb</filename> files. + </para> + + <para><indexterm> + <primary>idmap backend</primary> + </indexterm><indexterm> + <primary>mapping</primary> + </indexterm> + If the parameter + <smbconfoption><name>idmap backend</name><value>ldap:ldap://myserver.domain</value></smbconfoption> + was specified and the LDAP server has been configured with a container in which it may + store the IDMAP entries, all Domain Members may share a common mapping. + </para></listitem> + </itemizedlist> + </para> + + <para> + Irrespective of how &smb.conf; is configured, winbind creates and caches a local copy of + the ID mapping database. It uses the <filename>winbindd_idmap.tdb</filename>, and + <filename>winbindd_cache.tdb</filename> files to do this. + </para> + + <para> + Which of the above resolver methods is chosen is determined by the way that Samba is configured + in the &smb.conf; file. Some of the configuration options are rather less than obvious to the + casual user. + </para></listitem> + + <listitem><para><indexterm> + <primary>winbind enable local accounts</primary> + </indexterm><indexterm> + <primary>Domain Member</primary> + <secondary>servers</secondary> + </indexterm><indexterm> + <primary>Domain Controllers</primary> + </indexterm> + If you wish to make use of accounts (users and/or groups) that are local to (i.e., capable + of being resolved using) the name service switch (NSS) facility, it is imperative to use the + <smbconfoption><name>winbind enable local accounts</name><value>Yes</value></smbconfoption> + in the &smb.conf; file. This parameter specifically applies only to Domain Controllers, + not to Domain Member servers. + </para></listitem> + </itemizedlist> + + <para><indexterm> + <primary>Posix accounts</primary> + </indexterm><indexterm> + <primary>Samba accounts</primary> + </indexterm><indexterm> + <primary>LDAP</primary> + </indexterm> + For many administrators, it should be plain that the use of an LDAP-based repository for all network + accounts (both for Posix accounts as well as for Samba accounts) provides the most elegant and + controllable facility. You eventually appreciate the decision to use LDAP. + </para> + + <para><indexterm> + <primary>nss_ldap</primary> + </indexterm><indexterm> + <primary>identifiers</primary> + </indexterm><indexterm> + <primary>resolve</primary> + </indexterm> + If your network account information resides in an LDAP repository, you should use it ahead of any + alternative method. This means that if it is humanly possible to use the <command>nss_ldap</command> + tools to resolve UNIX account UIDs/GIDs via LDAP, this is the preferred solution, as it provides + a more readily controllable method for asserting the exact same user and group identifiers + throughout the network. + </para> + + <para><indexterm> + <primary>Domain Member</primary> + <secondary>server</secondary> + </indexterm><indexterm> + <primary>winbind trusted domains only</primary> + </indexterm><indexterm> + <primary>getpwnam</primary> + </indexterm><indexterm> + <primary>smbd</primary> + </indexterm><indexterm> + <primary>Trusted Domains</primary> + </indexterm><indexterm> + <primary>External Domains</primary> + </indexterm> + In the situation where UNIX accounts are held on the Domain Member server itself, the only effective + way to use them involves the &smb.conf; entry + <smbconfoption><name>winbind trusted domains only</name><value>Yes</value></smbconfoption>. This forces + Samba (<command>smbd</command>) to perform a <command>getpwnam()</command> system call that can + then be controlled via <filename>/etc/nsswitch.conf</filename> file settings. The use of this parameter + disables the use of Samba with Trusted Domains (i.e., External Domains). + </para> + + <para><indexterm> + <primary>appliance mode</primary> + </indexterm><indexterm> + <primary>Domain Member</primary> + <secondary>server</secondary> + </indexterm><indexterm> + <primary>winbindd</primary> + </indexterm><indexterm> + <primary>automatically allocate</primary> + </indexterm> + Winbind can be used to create an appliance mode Domain Member server. In this capacity, <command>winbindd</command> + is configured to automatically allocate UIDs/GIDs from numeric ranges set in the &smb.conf; file. The allocation + is made for all accounts that connect to that Domain Member server, whether within its own Domain or from + Trusted Domains. If not stored in an LDAP backend, each Domain Member maintains its own unique mapping database. + This means that it is almost certain that a given user who accesses two Domain Member servers does not have the + same UID/GID on both servers &smbmdash; however, this is transparent to the Windows network user. This data + is stored in the <filename>winbindd_idmap.tdb</filename> and <filename>winbindd_cache.tdb</filename> files. + </para> + + <para><indexterm> + <primary>mapping</primary> + </indexterm> + The use of an LDAP backend for the Winbind IDMAP facility permits Windows Domain security identifiers (SIDs) + mappings to UIDs/GIDs to be stored centrally. The result is a consistent mapping across all Domain Member + servers so configured. This solves one of the major headaches for network administrators who need to copy + files between/across network file servers. + </para> + + </sect2> + + <sect2> + <title>Political Issues</title> + + <para><indexterm> + <primary>OpenLDAP</primary> + </indexterm><indexterm> + <primary>NIS</primary> + </indexterm><indexterm> + <primary>yellow pages</primary> + <see>NIS</see> + </indexterm><indexterm> + <primary>identity management</primary> + </indexterm> + One of the most fierce conflicts recently being waged is one of resistance to the adoption of LDAP, in + particular OpenLDAP, as a replacement for UNIX NIS (previously called Yellow Pages). Let's face it, LDAP + is different and requires a new approach to the need for a better identity management solution. The more + you work with LDAP, the more its power and flexibility emerges from its dark, cavernous chasm. + </para> + + <para> + LDAP is a most suitable solution for heterogenous environments. If you need crypto, add Kerberos. + The reason these are preferable is because they are heterogenous. Windows solutions of this sort are NOT + heterogenous by design. This is fundamental &smbmdash; it isn't religious or political. This also doesn't say that + you can't use Windows Active Directory in a heterogenous environment &smbmdash; it can be done, it just requires + commercial integration products &smbmdash; it's just not what Active Directory was designed for. + </para> + + <para><indexterm> + <primary>directory</primary> + </indexterm><indexterm> + <primary>management</primary> + </indexterm> + A number of long-term UNIX devotees have recently commented in various communications that the Samba Team + is the first application group to almost force network administrators to use LDAP. It should be pointed + out that we resisted this as long as we could. It is not out of laziness or out of malice that LDAP has + finally emerged as the preferred identity management backend for Samba. We recommend LDAP for your total + organizational directory needs. + </para> + + </sect2> + +</sect1> + +<sect1> + <title>Implementation</title> + + <para><indexterm> + <primary>Domain Member</primary> + <secondary>server</secondary> + </indexterm><indexterm> + <primary>Domain Member</primary> + <secondary>client</secondary> + </indexterm><indexterm> + <primary>Domain Controller</primary> + </indexterm> + The Domain Member server and the Domain Member client are at the center of focus in this chapter. + Configuration of Samba-3 Domain Controller has been covered in earlier chapters, so if your + interest is in Domain Controller configuration, you will not find that here. You will find good + oil that helps you to add Domain Member servers and clients. + </para> + + <para><indexterm> + <primary>Domain Member</primary> + <secondary>workstations</secondary> + </indexterm> + In practice, Domain Member servers and Domain Member workstations are very different entities, but in + terms of technology they share similar core infrastructure. A technologist would argue that servers + and workstations are identical. Many users would argue otherwise, given that in a well-disciplined + environment a workstation (client) is a device from which a user creates documents and files that + are located on servers. A workstation is frequently viewed as a disposable (easy to replace) item, + but a server is viewed as a core component of the business. + </para> + + <para><indexterm> + <primary>workstation</primary> + </indexterm> + One can look at this another way. If a workstation breaks down, one user is affected, but if a + server breaks down, hundreds of users may not be able to work. The services that a workstation + must provide are document and file production oriented; a server provides information storage + and is distribution oriented. + </para> + + <para><indexterm> + <primary>authentication process</primary> + </indexterm><indexterm> + <primary>logon process</primary> + </indexterm><indexterm> + <primary>user identities</primary> + </indexterm> + <emphasis>Why is this important?</emphasis> &smbmdash; For starters, we must identify what + components of the operating system and its environment must be configured. Also, it is necessary + to recognize where the interdependencies between the various services to be used are. + In particular, it is important to understand the operation of each critical part of the + authentication process, the logon process, and how user identities get resolved and applied + within the operating system and applications (like Samba) that depend on this and may + actually contribute to it. + </para> + + <para> + So, while here we demonstrate how to implement the technology. It is done within a context of + what type of service need must be fulfilled. + </para> + + <sect2 id="sdcsdmldap"> + <title>Samba Domain with Samba Domain Member Server &smbmdash; Using LDAP</title> + + <para><indexterm> + <primary>ldapsam</primary> + </indexterm><indexterm> + <primary>ldapsam backend</primary> + </indexterm><indexterm> + <primary>IDMAP</primary> + </indexterm><indexterm> + <primary>mapping</primary> + <secondary>consistent</secondary> + </indexterm><indexterm> + <primary>winbindd</primary> + </indexterm><indexterm> + <primary>foreign SID</primary> + </indexterm> + In this example, it is assumed that you have Samba PDC/BDC servers. This means you are using + an LDAP ldapsam backend. In this example, we are adding to the LDAP backend database (directory) + containers for use by the IDMAP facility. This makes it possible to have globally consistent + mapping of SIDs to/from UIDs/GIDs. This means that you are running <command>winbindd</command> + as part of your configuration. The primary purpose of running <command>winbindd</command> (within + this operational context) is to permit mapping of foreign SIDs (those not originating from our + own Domain). Foreign SIDs can come from any external Domain or from Windows clients that do not + belong to a Domain. + </para> + + <para><indexterm> + <primary>winbindd</primary> + </indexterm><indexterm> + <primary>getpwnam</primary> + </indexterm><indexterm> + <primary>NSS</primary> + </indexterm> + If your installation is accessed only from clients that are members of your own domain, then + it is not necessary to run <command>winbindd</command> as long as all users can be resolved + locally via the <command>getpwnam()</command> system call. On NSS-enabled systems, this condition + is met by having: + </para> + + <itemizedlist> + <listitem><para><indexterm> + <primary>/etc/passwd</primary> + </indexterm><indexterm> + <primary>/etc/group</primary> + </indexterm> + All accounts in <filename>/etc/passwd</filename> or in <filename>/etc/group</filename>. + </para></listitem> + + <listitem><para><indexterm> + <primary>NSS</primary> + </indexterm><indexterm> + <primary>compat</primary> + </indexterm><indexterm> + <primary>compat</primary> + </indexterm><indexterm> + <primary>ldap</primary> + </indexterm><indexterm> + <primary>nis</primary> + </indexterm><indexterm> + <primary>nisplus</primary> + </indexterm><indexterm> + <primary>hesoid</primary> + </indexterm><indexterm> + <primary>ldap</primary> + </indexterm><indexterm> + <primary>nss_ldap</primary> + </indexterm><indexterm> + <primary>PADL Software</primary> + </indexterm> + Resolution via NSS. On NSS-enabled systems, there is usually a facility to resolve IDs + via multiple methods. The methods typically include: <command>files, compat, db, ldap, + nis, nisplus, hesoid.</command> When correctly installed, Samba adds to this list + the <command>winbindd</command> facility. The ldap facility is frequently the nss_ldap + tool provided by PADL Software. + </para></listitem> + </itemizedlist> + + <para><indexterm> + <primary>Identity resolution</primary> + </indexterm> + The diagram in <link linkend="ch9-sambadc"/> demonstrates the relationship of samba and system + components that are involved in the Identity resolution process where Samba is used as a Domain + Member server within a Samba Domain Control network. + </para> + +<figure id="ch9-sambadc"> + <title>Samba Domain: Samba Member Server</title> + <mediaobject> + <imageobject role="latex"> + <imagedata fileref="guide/images/chap9-SambaDC.png" scale="75" scalefit="1"/> + </imageobject> + <imageobject> + <imagedata fileref="guide/images/chap9-SambaDC.png" scale="75" scalefit="1"/> + </imageobject> + </mediaobject> +</figure> + + <para><indexterm> + <primary>IDMAP</primary> + </indexterm><indexterm> + <primary>foreign</primary> + </indexterm> + In this example configuration, Samba will directly search the LDAP-based passwd backend ldapsam + to obtain authentication and user identity information. The IDMAP information is stored in the LDAP + backend so that it can be shared by all Domain Member servers so that every user will have a + consistent UID and GID across all of them. The IDMAP facility will be used for all foreign + (i.e., not having the same SID as the Domain it is a member of) Domains. The configuration of + NSS will ensure that all unix processes will obtain a consistent UID/GID. + </para> + + <para> + The instructions given here apply to the Samba environment as shown in Chapters 6 and 7. + If your network does not have an LDAP slave server (i.e., Chapter 6 configuration), you + must change the target LDAP server from <constant>lapdc</constant> to <constant>massive.</constant> + </para> + + <procedure> + <title>Configuration of LDAP-Based Identity Resolution</title> + + <step><para> + Create the &smb.conf; file as shown in <link linkend="ch9-sdmsdc"/>. Locate + this file in the directory <filename>/etc/samba</filename>. + </para></step> + + <step><para><indexterm> + <primary>ldap.conf</primary> + </indexterm> + Configure the file that will be used by <constant>nss_ldap</constant> to + locate and communicate with the LDAP server. This file is called <filename>ldap.conf</filename>. + If your implementation of <constant>nss_ldap</constant> is consistent with + the defaults suggested by PADL (the authors), it will be located in the + <filename>/etc</filename> directory. On some systems, the default location is + the <filename>/etc/openldap</filename> directory. Change the parameters inside + the file that is located on your OS so it matches <link linkend="ch9-sdmlcnf"/>. + To find the correct location of this file, you can obtain this from the + library that will be used by executing the following: +<screen> +&rootprompt; strings /lib/libnss_ldap* | grep ldap.conf +/etc/ldap.conf +</screen> + </para></step> + + <step><para> + Configure the name service switch (NSS) control file so it matches the one shown + in <link linkend="ch9-sdmnss"/>. + </para></step> + + <step><para><indexterm> + <primary>Identity resolution</primary> + </indexterm><indexterm> + <primary>getent</primary> + </indexterm> + Before proceeding to configure Samba, validate the operation of the NSS Identity + resolution via LDAP by executing: +<screen> +&rootprompt; getent passwd +... +root:x:0:512:Netbios Domain Administrator:/root:/bin/false +nobody:x:999:514:nobody:/dev/null:/bin/false +bobj:x:1000:513:Robert Jordan:/home/bobj:/bin/bash +stans:x:1001:513:Stanley Soroka:/home/stans:/bin/bash +chrisr:x:1002:513:Christine Roberson:/home/chrisr:/bin/bash +maryv:x:1003:513:Mary Vortexis:/home/maryv:/bin/bash +jht:x:1004:513:John H Terpstra:/home/jht:/bin/bash +bldg1$:x:1006:553:bldg1$:/dev/null:/bin/false +temptation$:x:1009:553:temptation$:/dev/null:/bin/false +vaioboss$:x:1005:553:vaioboss$:/dev/null:/bin/false +fran$:x:1008:553:fran$:/dev/null:/bin/false +josephj:x:1007:513:Joseph James:/home/josephj:/bin/bash +</screen> + You should notice the location of the users' home directories. First, make certain that + the home directories exist on the Domain Member server; otherwise, the home directory + share is not available. The home directories could be mounted off a domain controller + using NFS, or by any other suitable means. Second, the absence of the Domain name in the + home directory path is indicative that Identity resolution is not being done via Winbind. +<screen> +&rootprompt; getent group +... +Domain Admins:x:512:root,jht +Domain Users:x:513:bobj,stans,chrisr,maryv,jht,josephj +Domain Guests:x:514: +Accounts:x:1000: +Finances:x:1001: +PIOps:x:1002: +sammy:x:4321: +</screen> + <indexterm> + <primary>secondary group</primary> + </indexterm><indexterm> + <primary>primary group</primary> + </indexterm><indexterm> + <primary>group membership</primary> + </indexterm> + This shows that all is working as it should. Notice that in the LDAP database + the users primary and secondary group memberships are identical. It is not + necessary to add secondary group memberships (in the group database) if the + user is already a member via primary group membership in the password database. + When using winbind, it is in fact undesirable to do this as it results in + doubling up of group memberships and may break winbind under certain conditions. + </para></step> + + <step><para><indexterm> + <primary>slapcat</primary> + </indexterm> + The LDAP directory must have a container object for IDMAP data. There are several ways you can + check that your LDAP database is able to receive IDMAP information. One of the simplest is to + execute: +<screen> +&rootprompt; slapcat | grep -i idmap +dn: ou=Idmap,dc=abmas,dc=biz +ou: idmap +</screen> + <indexterm> + <primary>ldapadd</primary> + </indexterm> + If the execution of this command does not return IDMAP entries, you need to create an LDIF + template file (see <link linkend="ch9-ldifadd"/>). You can add the required entries using the following command: +<screen> +&rootprompt; ldapadd -x -D "cn=Manager,dc=abmas,dc=biz" \ + -w not24get < /etc/openldap/idmap.LDIF +</screen> + Samba automatically populates this LDAP directory container when it needs to. + </para></step> + + <step><para><indexterm> + <primary>net</primary> + <secondary>rpc</secondary> + <tertiary>join</tertiary> + </indexterm><indexterm> + <primary>Domain join</primary> + </indexterm> + The system is ready to join the Domain. Execute the following: +<screen> +net rpc join -U root%not24et +Joined domain MEGANET2. +</screen> + This indicates that the Domain join succeeded. + </para></step> + + <step><para> + You may now start Samba in the usual manner and your Samba Domain Member server + is ready for use. Just add shares as required. + </para></step> + + </procedure> + +<smbconfexample id="ch9-sdmsdc"> +<title>Samba Domain Member in Samba Domain Control Context &smbmdash; &smb.conf; File</title> +<smbconfcomment>Global parameters</smbconfcomment> +<smbconfsection>[global]</smbconfsection> +<smbconfoption><name>unix charset</name><value>LOCALE</value></smbconfoption> +<smbconfoption><name>workgroup</name><value>MEGANET2</value></smbconfoption> +<smbconfoption><name>security</name><value>DOMAIN</value></smbconfoption> +<smbconfoption><name>username map</name><value>/etc/samba/smbusers</value></smbconfoption> +<smbconfoption><name>log level</name><value>10</value></smbconfoption> +<smbconfoption><name>syslog</name><value>0</value></smbconfoption> +<smbconfoption><name>log file</name><value>/var/log/samba/%m</value></smbconfoption> +<smbconfoption><name>max log size</name><value>50</value></smbconfoption> +<smbconfoption><name>smb ports</name><value>139 445</value></smbconfoption> +<smbconfoption><name>name resolve order</name><value>wins bcast hosts</value></smbconfoption> +<smbconfoption><name>printcap name</name><value>CUPS</value></smbconfoption> +<smbconfoption><name>wins server</name><value>192.168.2.1</value></smbconfoption> +<smbconfoption><name>ldap suffix</name><value>dc=abmas,dc=biz</value></smbconfoption> +<smbconfoption><name>ldap machine suffix</name><value>ou=People</value></smbconfoption> +<smbconfoption><name>ldap user suffix</name><value>ou=People</value></smbconfoption> +<smbconfoption><name>ldap group suffix</name><value>ou=Groups</value></smbconfoption> +<smbconfoption><name>ldap idmap suffix</name><value>ou=Idmap</value></smbconfoption> +<smbconfoption><name>ldap admin dn</name><value>cn=Manager,dc=abmas,dc=biz</value></smbconfoption> +<smbconfoption><name>idmap backend</name><value>ldap:ldap://lapdc.abmas.biz</value></smbconfoption> +<smbconfoption><name>idmap uid</name><value>10000-20000</value></smbconfoption> +<smbconfoption><name>idmap gid</name><value>10000-20000</value></smbconfoption> +<smbconfoption><name>winbind trusted domains only</name><value>Yes</value></smbconfoption> +<smbconfoption><name>printer admin</name><value>root</value></smbconfoption> +<smbconfoption><name>printing</name><value>cups</value></smbconfoption> + +<smbconfsection>[homes]</smbconfsection> +<smbconfoption><name>comment</name><value>Home Directories</value></smbconfoption> +<smbconfoption><name>valid users</name><value>%S</value></smbconfoption> +<smbconfoption><name>read only</name><value>No</value></smbconfoption> +<smbconfoption><name>browseable</name><value>No</value></smbconfoption> + +<smbconfsection>[printers]</smbconfsection> +<smbconfoption><name>comment</name><value>SMB Print Spool</value></smbconfoption> +<smbconfoption><name>path</name><value>/var/spool/samba</value></smbconfoption> +<smbconfoption><name>guest ok</name><value>Yes</value></smbconfoption> +<smbconfoption><name>printable</name><value>Yes</value></smbconfoption> +<smbconfoption><name>browseable</name><value>No</value></smbconfoption> + +<smbconfsection>[print$]</smbconfsection> +<smbconfoption><name>comment</name><value>Printer Drivers</value></smbconfoption> +<smbconfoption><name>path</name><value>/var/lib/samba/drivers</value></smbconfoption> +<smbconfoption><name>admin users</name><value>root, Administrator</value></smbconfoption> +<smbconfoption><name>write list</name><value>root</value></smbconfoption> +</smbconfexample> + +<example id="ch9-ldifadd"> +<title>LDIF IDMAP Add-On Load File &smbmdash; File: /etc/openldap/idmap.LDIF</title> +<screen> +dn: ou=Idmap,dc=abmas,dc=biz +objectClass: organizationalUnit +ou: idmap +structuralObjectClass: organizationalUnit +</screen> +</example> + +<example id="ch9-sdmlcnf"> +<title>Configuration File for NSS LDAP Support &smbmdash; <filename>/etc/ldap.conf</filename></title> +<screen> +URI ldap://massive.abmas.biz ldap://massive.abmas.biz:636 +host 192.168.2.1 +base dc=abmas,dc=biz +binddn cn=Manager,dc=abmas,dc=biz +bindpw not24get + +pam_password exop + +nss_base_passwd ou=People,dc=abmas,dc=biz?one +nss_base_shadow ou=People,dc=abmas,dc=biz?one +nss_base_group ou=Groups,dc=abmas,dc=biz?one +ssl no +</screen> +</example> + +<example id="ch9-sdmnss"> +<title>NSS using LDAP for Identity Resolution &smbmdash; File: <filename>/etc/nsswitch.conf</filename></title> +<screen> +passwd: compat ldap +group: compat ldap + +hosts: files dns wins +networks: files dns + +services: files +protocols: files +rpc: files +ethers: files +netmasks: files +netgroup: files +publickey: files + +bootparams: files +automount: files +aliases: files +</screen> +</example> + + </sect2> + + <sect2 id="wdcsdm"> + <title>NT4/Samba Domain with Samba Domain Member Server &smbmdash; Using Winbind</title> + + <para> + You need to use this method for creating a Samba Domain Member server if any of the following conditions + prevail: + </para> + + <itemizedlist> + <listitem><para> + LDAP support (client) is not installed on the system. + </para></listitem> + + <listitem><para> + There are mitigating circumstances forcing a decision not to use LDAP. + </para></listitem> + + <listitem><para> + The Samba Domain Member server must be part of a Windows NT4 Domain. + </para></listitem> + </itemizedlist> + + <para><indexterm> + <primary>Windows ADS Domain</primary> + </indexterm><indexterm> + <primary>Samba Domain</primary> + </indexterm><indexterm> + <primary>LDAP</primary> + </indexterm> + Later in the chapter, you can see how to configure a Samba Domain Member server for a Windows ADS Domain. + Right now your objective is to configure a Samba server that can be a member of a Windows NT4 style + Domain and/or does not use LDAP. + </para> + + <note><para><indexterm> + <primary>duplicate accounts</primary> + </indexterm> + If you use <command>winbind</command> for Identity resolution, do make sure that there are no + duplicate accounts. + </para> + + <para><indexterm> + <primary>/etc/passwd</primary> + </indexterm> + For example, do not have more than one account that has UID=0 in the password database. If there + is an account called <constant>root</constant> in the <filename>/etc/passwd</filename> database, + it is okay to have an account called <constant>root</constant> in the LDAP ldapsam or in the + tdbsam. But if there are two accounts in the passdb backend that have the same UID, winbind will + break. This means that the <constant>Administrator</constant> account must be called + <constant>root</constant>. + </para> + + <para><indexterm> + <primary>/etc/passwd</primary> + </indexterm><indexterm> + <primary>ldapsam</primary> + </indexterm><indexterm> + <primary>tdbsam</primary> + </indexterm> + Winbind will break if there is an account in <filename>/etc/passwd</filename> that has + the same UID as an account that is in LDAP ldapsam (or in tdbsam) but that differs in name only. + </para></note> + + <para><indexterm> + <primary>credentials</primary> + </indexterm><indexterm> + <primary>traverse</primary> + </indexterm><indexterm> + <primary>wide-area</primary> + </indexterm><indexterm> + <primary>network</primary> + <secondary>wide-area</secondary> + </indexterm><indexterm> + <primary>tdbdump</primary> + </indexterm> + The following configuration uses CIFS/SMB protocols alone to obtain user and group credentials. + The winbind information is locally cached in the <filename>winbindd_cache.tdb winbindd_idmap.tdb</filename> + files. This provides considerable performance benefits compared with the LDAP solution, particularly + where the LDAP lookups must traverse wide-area network links. You may examine the contents of these + files using the tool <command>tdbdump</command>, though you may have to build this from the Samba + source code if it has not been supplied as part of a binary package distribution that you may be using. + </para> + + <procedure> + <title>Configuration of Winbind-Based Identity Resolution</title> + + <step><para> + Using your favorite text editor, create the &smb.conf; file so it has the contents + shown in <link linkend="ch0-NT4DSDM"/>. + </para></step> + + <step><para><indexterm> + <primary>/etc/nsswitch.conf</primary> + </indexterm> + Edit the <filename>/etc/nsswitch.conf</filename> so it has the entries shown in + <link linkend="ch9-nsswbnd"/>. + </para></step> + + <step><para><indexterm> + <primary>net</primary> + <secondary>rpc</secondary> + <tertiary>join</tertiary> + </indexterm> + The system is ready to join the Domain. Execute the following: +<screen> +net rpc join -U root%not24et +Joined domain MEGANET2. +</screen> + This indicates that the Domain join succeed. + + </para></step> + + <step><para><indexterm> + <primary>winbind</primary> + </indexterm><indexterm> + <primary>wbinfo</primary> + </indexterm> + Validate operation of <command>winbind</command> using the <command>wbinfo</command> + tool as follows: +<screen> +&rootprompt; wbinfo -u +MEGANET2+root +MEGANET2+nobody +MEGANET2+jht +MEGANET2+maryv +MEGANET2+billr +MEGANET2+jelliott +MEGANET2+dbrady +MEGANET2+joeg +MEGANET2+balap +</screen> + This shows that Domain users have been listed correctly. +<screen> +&rootprompt; wbinfo -g +MEGANET2+Domain Admins +MEGANET2+Domain Users +MEGANET2+Domain Guests +MEGANET2+Accounts +MEGANET2+Finances +MEGANET2+PIOps +</screen> + This shows that Domain groups have been correctly obtained also. + </para></step> + + <step><para><indexterm> + <primary>NSS</primary> + </indexterm><indexterm> + <primary>getent</primary> + </indexterm><indexterm> + <primary>winbind</primary> + </indexterm> + The next step verifies that NSS is able to obtain this information + correctly from <command>winbind</command> also. +<screen> +&rootprompt; getent passwd +... +MEGANET2+root:x:10000:10001:NetBIOS Domain Admin: + /home/MEGANET2/root:/bin/bash +MEGANET2+nobody:x:10001:10001:nobody: + /home/MEGANET2/nobody:/bin/bash +MEGANET2+jht:x:10002:10001:John H Terpstra: + /home/MEGANET2/jht:/bin/bash +MEGANET2+maryv:x:10003:10001:Mary Vortexis: + /home/MEGANET2/maryv:/bin/bash +MEGANET2+billr:x:10004:10001:William Randalph: + /home/MEGANET2/billr:/bin/bash +MEGANET2+jelliott:x:10005:10001:John G Elliott: + /home/MEGANET2/jelliott:/bin/bash +MEGANET2+dbrady:x:10006:10001:Darren Brady: + /home/MEGANET2/dbrady:/bin/bash +MEGANET2+joeg:x:10007:10001:Joe Green: + /home/MEGANET2/joeg:/bin/bash +MEGANET2+balap:x:10008:10001:Bala Pillay: + /home/MEGANET2/balap:/bin/bash +</screen> + The user account information has been correctly obtained. This information has + been merged with the winbind template information configured in the &smb.conf; file. +<screen> +&rootprompt;# getent group +... +MEGANET2+Domain Admins:x:10000:MEGANET2+root,MEGANET2+jht +MEGANET2+Domain Users:x:10001:MEGANET2+jht,MEGANET2+maryv,\ + MEGANET2+billr,MEGANET2+jelliott,MEGANET2+dbrady,\ + MEGANET2+joeg,MEGANET2+balap +MEGANET2+Domain Guests:x:10002:MEGANET2+nobody +MEGANET2+Accounts:x:10003: +MEGANET2+Finances:x:10004: +MEGANET2+PIOps:x:10005: +</screen> + </para></step> + + <step><para> + The Samba member server of a Windows NT4 Domain is ready for use. + </para></step> + </procedure> + +<smbconfexample id="ch0-NT4DSDM"> +<title>Samba Domain Member Server &smb.conf; File for NT4 Domain</title> +<smbconfcomment>Global parameters</smbconfcomment> +<smbconfsection>[global]</smbconfsection> +<smbconfoption><name>unix charset</name><value>LOCALE</value></smbconfoption> +<smbconfoption><name>workgroup</name><value>MEGANET2</value></smbconfoption> +<smbconfoption><name>security</name><value>DOMAIN</value></smbconfoption> +<smbconfoption><name>username map</name><value>/etc/samba/smbusers</value></smbconfoption> +<smbconfoption><name>log level</name><value>1</value></smbconfoption> +<smbconfoption><name>syslog</name><value>0</value></smbconfoption> +<smbconfoption><name>log file</name><value>/var/log/samba/%m</value></smbconfoption> +<smbconfoption><name>max log size</name><value>0</value></smbconfoption> +<smbconfoption><name>smb ports</name><value>139 445</value></smbconfoption> +<smbconfoption><name>name resolve order</name><value>wins bcast hosts</value></smbconfoption> +<smbconfoption><name>printcap name</name><value>CUPS</value></smbconfoption> +<smbconfoption><name>wins server</name><value>192.168.2.1</value></smbconfoption> +<smbconfoption><name>idmap uid</name><value>10000-20000</value></smbconfoption> +<smbconfoption><name>idmap gid</name><value>10000-20000</value></smbconfoption> +<smbconfoption><name>template primary group</name><value>"Domain Users"</value></smbconfoption> +<smbconfoption><name>template shell</name><value>/bin/bash</value></smbconfoption> +<smbconfoption><name>winbind separator</name><value>+</value></smbconfoption> +<smbconfoption><name>printer admin</name><value>root</value></smbconfoption> +<smbconfoption><name>hosts allow</name><value>192.168.2., 192.168.3., 127.</value></smbconfoption> +<smbconfoption><name>printing</name><value>cups</value></smbconfoption> + +<smbconfsection>[homes]</smbconfsection> +<smbconfoption><name>comment</name><value>Home Directories</value></smbconfoption> +<smbconfoption><name>valid users</name><value>%S</value></smbconfoption> +<smbconfoption><name>read only</name><value>No</value></smbconfoption> +<smbconfoption><name>browseable</name><value>No</value></smbconfoption> + +<smbconfsection>[printers]</smbconfsection> +<smbconfoption><name>comment</name><value>SMB Print Spool</value></smbconfoption> +<smbconfoption><name>path</name><value>/var/spool/samba</value></smbconfoption> +<smbconfoption><name>guest ok</name><value>Yes</value></smbconfoption> +<smbconfoption><name>printable</name><value>Yes</value></smbconfoption> +<smbconfoption><name>browseable</name><value>No</value></smbconfoption> + +<smbconfsection>[print$]</smbconfsection> +<smbconfoption><name>comment</name><value>Printer Drivers</value></smbconfoption> +<smbconfoption><name>path</name><value>/var/lib/samba/drivers</value></smbconfoption> +<smbconfoption><name>admin users</name><value>root, Administrator</value></smbconfoption> +<smbconfoption><name>write list</name><value>root</value></smbconfoption> +</smbconfexample> + +<example id="ch9-nsswbnd"> +<title>Name Service Switch Control File: <filename>/etc/nsswitch.conf</filename></title> +<screen> +# /etc/nsswitch.conf + +passwd: compat winbind +group: compat winbind + +hosts: files dns wins +networks: files dns + +services: files +protocols: files +rpc: files +ethers: files +netmasks: files +netgroup: files +publickey: files + +bootparams: files +automount: files +aliases: files +</screen> +</example> + + </sect2> + + <sect2 id="adssdm"> + <title>Active Directory Domain with Samba Domain Member Server</title> + + <para><indexterm> + <primary>Active Directory</primary> + <secondary>join</secondary> + </indexterm><indexterm> + <primary>Kerberos</primary> + </indexterm><indexterm> + <primary>Domain Member</primary> + <secondary>server</secondary> + </indexterm> + One of the much-sought-after features new to Samba-3 is the ability to join an Active Directory + Domain using Kerberos protocols. This makes it possible to operate an entire Windows network + without the need to run NetBIOS over TCP/IP and permits more secure networking in general. An + exhaustively complete discussion of the protocols is not possible in this book; perhaps a + later book may explore the intricacies of the NetBIOS-less operation that Samba-3 can participate + in. For now, we simply focus on how a Samba-3 server can be made a Domain Member server. + </para> + + <para><indexterm> + <primary>Active Directory</primary> + </indexterm><indexterm> + <primary>LDAP</primary> + </indexterm><indexterm> + <primary>Identity resolution</primary> + </indexterm><indexterm> + <primary>Kerberos</primary> + </indexterm> + The diagram in <link linkend="ch9-adsdc"/> demonstrates how Samba-3 interfaces with + Microsoft Active Directory components. It should be noted that if Microsoft Windows Services + for UNIX has been installed and correctly configured, it is possible to use client LDAP + for Identity resolution just as can be done with Samba-3 when using an LDAP passdb backend. + The UNIX tool that you need for this, as in the case of LDAP on UNIX/Linux, is the PADL + Software nss_ldap tool-set. Compared with use of winbind and Kerberos, the use of + LDAP-based Identity resolution is a little less secure. In view of the fact that this solution + requires additional software to be installed on the Windows 200x ADS Domain Controllers, + and that means more management overhead, it is likely that most Samba-3 ADS client sites + may elect to use winbind. + </para> + + <para> + Do not attempt to use this procedure if you are not 100 percent certain that the build of Samba-3 + you are using has been compiled and linked with all the tools necessary for this to work. + Given the importance of this step, you must first validate that the Samba-3 message block + daemon (<command>smbd</command>) has the necessary features. + </para> + + <para> + The hypothetical domain you are using in this example assumes that the Abmas London office + decided to take their own lead (some would say this is a typical behavior in a global + corporate world; besides, a little divergence and conflict makes for an interesting life). + The Windows Server 2003 ADS Domain is called <constant>london.abmas.biz</constant> and the + name of the server is <constant>W2K3S</constant>. In ADS realm terms, the Domain Controller + is known as <constant>w2k3s.london.abmas.biz</constant>. In NetBIOS nomenclature, the + Domain Name is <constant>LONDON</constant> and the server name is <constant>W2K3S</constant>. + </para> + +<figure id="ch9-adsdc"> + <title>Active Directory Domain: Samba Member Server</title> + <mediaobject> + <imageobject role="latex"> + <imagedata fileref="guide/images/chap9-ADSDC.png" scale="75" scalefit="1"/> + </imageobject> + <imageobject> + <imagedata fileref="guide/images/chap9-SambaDC.png" scale="75" scalefit="1"/> + </imageobject> + </mediaobject> +</figure> + + <procedure> + <step><para><indexterm> + <primary>smbd</primary> + </indexterm> + Before you try to use Samba-3, you want to know for certain that your executables have + support for Kerberos and for LDAP. Execute the following to identify whether or + not this build is perhaps suitable for use: +<screen> +&rootprompt; cd /usr/sbin +&rootprompt; smbd -b | grep KRB + HAVE_KRB5_H + HAVE_ADDR_TYPE_IN_KRB5_ADDRESS + HAVE_KRB5 + HAVE_KRB5_AUTH_CON_SETKEY + HAVE_KRB5_GET_DEFAULT_IN_TKT_ETYPES + HAVE_KRB5_GET_PW_SALT + HAVE_KRB5_KEYBLOCK_KEYVALUE + HAVE_KRB5_KEYTAB_ENTRY_KEYBLOCK + HAVE_KRB5_MK_REQ_EXTENDED + HAVE_KRB5_PRINCIPAL_GET_COMP_STRING + HAVE_KRB5_SET_DEFAULT_IN_TKT_ETYPES + HAVE_KRB5_STRING_TO_KEY + HAVE_KRB5_STRING_TO_KEY_SALT + HAVE_LIBKRB5 +&rootprompt; smbd -b | grep LDAP +massive:/usr/sbin # smbd -b | grep LDAP + HAVE_LDAP_H + HAVE_LDAP + HAVE_LDAP_DOMAIN2HOSTLIST + HAVE_LDAP_INIT + HAVE_LDAP_INITIALIZE + HAVE_LDAP_SET_REBIND_PROC + HAVE_LIBLDAP + LDAP_SET_REBIND_PROC_ARGS +</screen> + This does look promising; <command>smbd</command> has been built with Kerberos and LDAP + support. You are relieved to know that it is safe to progress. + </para></step> + + <step><para><indexterm> + <primary>Kerberos</primary> + <secondary>libraries</secondary> + </indexterm><indexterm> + <primary>MIT Kerberos</primary> + </indexterm><indexterm> + <primary>Heimdal Kerberos</primary> + </indexterm><indexterm> + <primary>Kerberos</primary> + <secondary>MIT</secondary> + </indexterm><indexterm> + <primary>Kerberos</primary> + <secondary>Heimdal</secondary> + </indexterm><indexterm> + <primary>Red Hat Linux</primary> + </indexterm><indexterm> + <primary>SUSE Linux</primary> + </indexterm><indexterm> + <primary>SerNet</primary> + </indexterm><indexterm> + <primary>validated</primary> + </indexterm> + The next step is to identify which version of the Kerberos libraries have been used. + In order to permit Samba-3 to interoperate with Windows 2003 Active Directory, it is + essential that it has been linked with either MIT Kerberos version 1.3.1 or later, + or that it has been linked with Heimdal Kerberos 0.6 plus specific patches. You may + identify what version of the MIT Kerberos libraries are installed on your system by + executing (on Red Hat Linux): +<screen> +&rootprompt; rpm -q krb5 +</screen> + Or on SUSE Linux, execute: +<screen> +&rootprompt; rpm -q heimdal +</screen> + Please note that the RPMs provided by the Samba-Team are known to be working and have + been validated. Red Hat Linux RPMs may be obtained from the Samba FTP sites. SUSE + Linux RPMs may be obtained from <ulink url="ftp://ftp.sernet.de">Sernet</ulink> in + Germany. + </para> + + <para> + From this point on, you are certain that the Samba-3 build you are using has the + necessary capabilities. You can now configure Samba-3 and the name service + switcher (NSS). + </para></step> + + <step><para> + Using you favorite editor, configure the &smb.conf; file that is located in the + <filename>/etc/samba</filename> directory so that it has the contents shown + in <link linkend="ch9-adssdm"/>. + </para></step> + + <step><para> + Edit or create the NSS control file so it has the contents shown in <link linkend="ch9-nsswbnd"/>. + </para></step> + + <step><para><indexterm> + <primary>/etc/samba/secrets.tdb</primary> + </indexterm> + Delete the file <filename>/etc/samba/secrets.tdb</filename>, if it exists. Of course, you + do keep a backup, don't you? + </para></step> + + <step><para> + Delete the tdb files that cache Samba information. You keep a backup of the old + files, of course. You also remove all files to ensure that nothing can pollute your + nice, new configuration. Execute the following (example is for SUSE Linux): +<screen> +&rootprompt; rm /var/lib/samba/*tdb +</screen> + </para></step> + + <step><para><indexterm> + <primary>testparm</primary> + </indexterm> + Validate your &smb.conf; file using <command>testparm</command> (as you have + done previously). Correct all errors reported before proceeding. The command you + execute is: +<screen> +&rootprompt; testparm -s | less +</screen> + Now that you are satisfied that your Samba server is ready to join the Windows + ADS Domain, let's move on. + </para></step> + + <step><para><indexterm> + <primary>net</primary> + <secondary>ads</secondary> + <tertiary>join</tertiary> + </indexterm><indexterm> + <primary>Kerberos</primary> + </indexterm> + This is a good time to double-check everything and then execute the following + command when everything you have done has checked out okay: +<screen> +&rootprompt; net ads join -UAdministrator%not24get +Using short domain name -- LONDON +Joined 'FRAN' to realm 'LONDON.ABMAS.BIZ' +</screen> + You have successfully made your Samba-3 server a member of the ADS Domain + using Kerberos protocols. + </para> + + <para><indexterm> + <primary>silent return</primary> + </indexterm><indexterm> + <primary>failed join</primary> + </indexterm> + In the event that you receive no output messages, a silent return means that the + Domain join failed. You should use <command>ethereal</command> to identify what + may be failing. Common causes of a failed join include: + + <itemizedlist> + <listitem><para><indexterm> + <primary>name resolution</primary> + <secondary>Defective</secondary> + </indexterm> + Defective or misconfigured DNS name resolution. + </para></listitem> + + <listitem><para><indexterm> + <primary>Restrictive security</primary> + </indexterm> + Restrictive security settings on the Windows 200x ADS Domain controller + preventing needed communications protocols. You can check this by searching + the Windows Server 200x Event Viewer. + </para></listitem> + + <listitem><para> + Incorrectly configured &smb.conf; file settings. + </para></listitem> + + <listitem><para> + Lack of support of necessary Kerberos protocols because the version of MIT + Kerberos (or Heimdal) in use is not up to date enough to support the necessary + functionality. + </para></listitem> + </itemizedlist> + <indexterm> + <primary>net</primary> + <secondary>rpc</secondary> + <tertiary>join</tertiary> + </indexterm><indexterm> + <primary>RPC</primary> + </indexterm><indexterm> + <primary>mixed mode</primary> + </indexterm> + In any case, never execute the <command>net rpc join</command> command in an attempt + to join the Samba server to the Domain, unless you wish not to use the Kerberos + security protocols. Use of the older RPC-based Domain join facility requires that + Windows Server 200x ADS has been configured appropriately for mixed mode operation. + </para></step> + + <step><para><indexterm> + <primary>tdbdump</primary> + </indexterm><indexterm> + <primary>/etc/samba/secrets.tdb</primary> + </indexterm> + If the <command>tdbdump</command> is installed on your system (not essential), + you can look inside the <filename>/etc/samba/secrets.tdb</filename> file. If + you wish to do this, execute: +<screen> +&rootprompt; tdbdump secrets.tdb +{ +key = "SECRETS/SID/LONDON" +data = "\01\04\00\00\00\00\00\05\15\00\00\00\EBw\86\F1\ED\BD\ + F6{\5C6\E5W\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\ + 00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\ + 00\00\00\00\00\00\00\00" +} +{ +key = "SECRETS/MACHINE_PASSWORD/LONDON" +data = "le3Q5FPnN5.ueC\00" +} +{ +key = "SECRETS/MACHINE_SEC_CHANNEL_TYPE/LONDON" +data = "\02\00\00\00" +} +{ +key = "SECRETS/MACHINE_LAST_CHANGE_TIME/LONDON" +data = "E\89\F6?" +} +</screen> + This is given to demonstrate to the skeptics that this process truly does work. + </para></step> + + <step><para> + It is now time to start Samba in the usual way (as has been done many time before + in this book). + </para></step> + + <step><para><indexterm> + <primary>wbinfo</primary> + </indexterm> + This is a good time to verify that everything is working. First, check that + winbind is able to obtain the list of users and groups from the ADS Domain Controller. + Execute the following: +<screen> +&rootprompt; wbinfo -u +LONDON+Administrator +LONDON+Guest +LONDON+SUPPORT_388945a0 +LONDON+krbtgt +LONDON+jht +</screen> + Good, the list of users was obtained. Now do likewise for group accounts: +<screen> +&rootprompt; wbinfo -g +LONDON+Domain Computers +LONDON+Domain Controllers +LONDON+Schema Admins +LONDON+Enterprise Admins +LONDON+Domain Admins +LONDON+Domain Users +LONDON+Domain Guests +LONDON+Group Policy Creator Owners +LONDON+DnsUpdateProxy +</screen> + Excellent. That worked also, as expected. + </para></step> + + <step><para><indexterm> + <primary>getent</primary> + </indexterm> + Now repeat this via NSS to validate that full Identity resolution is + functional as required. Execute: +<screen> +&rootprompt; getent passwd +... +LONDON+Administrator:x:10000:10000:Administrator: + /home/LONDON/administrator:/bin/bash +LONDON+Guest:x:10001:10001:Guest: + /home/LONDON/guest:/bin/bash +LONDON+SUPPORT_388945a0:x:10002:10000:SUPPORT_388945a0: + /home/LONDON/support_388945a0:/bin/bash +LONDON+krbtgt:x:10003:10000:krbtgt: + /home/LONDON/krbtgt:/bin/bash +LONDON+jht:x:10004:10000:John H. Terpstra: + /home/LONDON/jht:/bin/bash +</screen> + Okay, ADS user accounts are being resolved. Now you try group resolution as follows: +<screen> +&rootprompt; getent group +... +LONDON+Domain Computers:x:10002: +LONDON+Domain Controllers:x:10003: +LONDON+Schema Admins:x:10004:LONDON+Administrator +LONDON+Enterprise Admins:x:10005:LONDON+Administrator +LONDON+Domain Admins:x:10006:LONDON+jht,LONDON+Administrator +LONDON+Domain Users:x:10000: +LONDON+Domain Guests:x:10001: +LONDON+Group Policy Creator Owners:x:10007:LONDON+Administrator +LONDON+DnsUpdateProxy:x:10008: +</screen> + This is very pleasing. Everything works as expected. + </para></step> + + <step><para><indexterm> + <primary>net</primary> + <secondary>ads</secondary> + <tertiary>info</tertiary> + </indexterm><indexterm> + <primary>Active Directory</primary> + <secondary>server</secondary> + </indexterm><indexterm> + <primary>Kerberos</primary> + </indexterm> + You may now perform final verification that communications between Samba-3 winbind and + the Active Directory server is using Kerberos protocols. Execute the following: +<screen> +&rootprompt; net ads info +LDAP server: 192.168.2.123 +LDAP server name: w2k3s +Realm: LONDON.ABMAS.BIZ +Bind Path: dc=LONDON,dc=ABMAS,dc=BIZ +LDAP port: 389 +Server time: Sat, 03 Jan 2004 02:44:44 GMT +KDC server: 192.168.2.123 +Server time offset: 2 +</screen> + It should be noted that Kerberos protocols are time-clock critical. You should + keep all server time clocks synchronized using the network time protocol (NTP). + In any case, the output we obtained confirms that all systems are operational. + </para></step> + + <step><para><indexterm> + <primary>net</primary> + <secondary>ads</secondary> + <tertiary>status</tertiary> + </indexterm> + There is one more action you elect to take, just because you are paranoid and disbelieving, + so you execute the following command: +<programlisting> +&rootprompt; net ads status -UAdministrator%not24get +objectClass: top +objectClass: person +objectClass: organizationalPerson +objectClass: user +objectClass: computer +cn: fran +distinguishedName: CN=fran,CN=Computers,DC=london,DC=abmas,DC=biz +instanceType: 4 +whenCreated: 20040103092006.0Z +whenChanged: 20040103092006.0Z +uSNCreated: 28713 +uSNChanged: 28717 +name: fran +objectGUID: 58f89519-c467-49b9-acb0-f099d73696e +userAccountControl: 69632 +badPwdCount: 0 +codePage: 0 +countryCode: 0 +badPasswordTime: 0 +lastLogoff: 0 +lastLogon: 127175965783327936 +localPolicyFlags: 0 +pwdLastSet: 127175952062598496 +primaryGroupID: 515 +objectSid: S-1-5-21-4052121579-2079768045-1474639452-1109 +accountExpires: 9223372036854775807 +logonCount: 13 +sAMAccountName: fran$ +sAMAccountType: 805306369 +operatingSystem: Samba +operatingSystemVersion: 3.0.2-SUSE +dNSHostName: fran +userPrincipalName: HOST/fran@LONDON.ABMAS.BIZ +servicePrincipalName: CIFS/fran.london.abmas.biz +servicePrincipalName: CIFS/fran +servicePrincipalName: HOST/fran.london.abmas.biz +servicePrincipalName: HOST/fran +objectCategory: CN=Computer,CN=Schema,CN=Configuration, + DC=london,DC=abmas,DC=biz +isCriticalSystemObject: FALSE +-------------- Security Descriptor (revision: 1, type: 0x8c14) +owner SID: S-1-5-21-4052121579-2079768045-1474639452-512 +group SID: S-1-5-21-4052121579-2079768045-1474639452-513 +------- (system) ACL (revision: 4, size: 120, number of ACEs: 2) +------- ACE (type: 0x07, flags: 0x5a, size: 0x38, + mask: 0x20, object flags: 0x3) +access SID: S-1-1-0 +access type: AUDIT OBJECT +Permissions: + [Write All Properties] +------- ACE (type: 0x07, flags: 0x5a, size: 0x38, + mask: 0x20, object flags: 0x3) +access SID: S-1-1-0 +access type: AUDIT OBJECT +Permissions: + [Write All Properties] +------- (user) ACL (revision: 4, size: 1944, number of ACEs: 40) +------- ACE (type: 0x00, flags: 0x00, size: 0x24, mask: 0xf01ff) +access SID: S-1-5-21-4052121579-2079768045-1474639452-512 +access type: ALLOWED +Permissions: [Full Control] +------- ACE (type: 0x00, flags: 0x00, size: 0x18, mask: 0xf01ff) +access SID: S-1-5-32-548 +... +------- ACE (type: 0x05, flags: 0x12, size: 0x38, + mask: 0x10, object flags: 0x3) +access SID: S-1-5-9 +access type: ALLOWED OBJECT +Permissions: + [Read All Properties] +-------------- End Of Security Descriptor +</programlisting> + And now you have conclusive proof that your Samba-3 ADS Domain Member Server + called <constant>FRAN</constant>, is able to communicate fully with the ADS + Domain Controllers. + </para></step> + </procedure> + + + <para> + Your Samba-3 ADS Domain Member server is ready for use. During training sessions, + you may be asked what is inside the <filename>winbindd_cache.tdb and winbindd_idmap.tdb</filename> + files. Since curiosity just took hold of you, execute the following: +<programlisting> +&rootprompt; tdbdump /var/lib/samba/winbindd_idmap.tdb +{ +key = "S-1-5-21-4052121579-2079768045-1474639452-501\00" +data = "UID 10001\00" +} +{ +key = "UID 10005\00" +data = "S-1-5-21-4052121579-2079768045-1474639452-1111\00" +} +{ +key = "GID 10004\00" +data = "S-1-5-21-4052121579-2079768045-1474639452-518\00" +} +{ +key = "S-1-5-21-4052121579-2079768045-1474639452-502\00" +data = "UID 10003\00" +} +... + +&rootprompt; tdbdump /var/lib/samba/winbindd_cache.tdb +{ +key = "UL/LONDON" +data = "\00\00\00\00bp\00\00\06\00\00\00\0DAdministrator\0D + Administrator-S-1-5-21-4052121579-2079768045-1474639452-500- + S-1-5-21-4052121579-2079768045-1474639452-513\05Guest\05 + Guest-S-1-5-21-4052121579-2079768045-1474639452-501- + S-1-5-21-4052121579-2079768045-1474639452-514\10 + SUPPORT_388945a0\10SUPPORT_388945a0. + S-1-5-21-4052121579-2079768045-1474639452-1001- + S-1-5-21-4052121579-2079768045-1474639452-513\06krbtgt\06 + krbtgt-S-1-5-21-4052121579-2079768045-1474639452-502- + S-1-5-21-4052121579-2079768045-1474639452-513\03jht\10 + John H. Terpstra.S-1-5-21-4052121579-2079768045-1474639452-1110- + S-1-5-21-4052121579-2079768045-1474639452-513" +} +{ +key = "GM/S-1-5-21-4052121579-2079768045-1474639452-512" +data = "\00\00\00\00bp\00\00\02\00\00\00. + S-1-5-21-4052121579-2079768045-1474639452-1110\03 + jht\01\00\00\00-S-1-5-21-4052121579-2079768045-1474639452-500\0D + Administrator\01\00\00\00" +} +{ +key = "SN/S-1-5-21-4052121579-2079768045-1474639452-513" +data = "\00\00\00\00xp\00\00\02\00\00\00\0CDomain Users" +} +{ +key = "GM/S-1-5-21-4052121579-2079768045-1474639452-518" +data = "\00\00\00\00bp\00\00\01\00\00\00- + S-1-5-21-4052121579-2079768045-1474639452-500\0D + Administrator\01\00\00\00" +} +{ +key = "SEQNUM/LONDON\00" +data = "xp\00\00C\92\F6?" +} +{ +key = "U/S-1-5-21-4052121579-2079768045-1474639452-1110" +data = "\00\00\00\00xp\00\00\03jht\10John H. Terpstra. + S-1-5-21-4052121579-2079768045-1474639452-1110- + S-1-5-21-4052121579-2079768045-1474639452-513" +} +{ +key = "NS/S-1-5-21-4052121579-2079768045-1474639452-502" +data = "\00\00\00\00bp\00\00- + S-1-5-21-4052121579-2079768045-1474639452-502" +} +{ +key = "SN/S-1-5-21-4052121579-2079768045-1474639452-1001" +data = "\00\00\00\00bp\00\00\01\00\00\00\10SUPPORT_388945a0" +} +{ +key = "SN/S-1-5-21-4052121579-2079768045-1474639452-500" +data = "\00\00\00\00bp\00\00\01\00\00\00\0DAdministrator" +} +{ +key = "U/S-1-5-21-4052121579-2079768045-1474639452-502" +data = "\00\00\00\00bp\00\00\06krbtgt\06krbtgt- + S-1-5-21-4052121579-2079768045-1474639452-502- + S-1-5-21-4052121579-2079768045-1474639452-513" +} +.... +</programlisting> + Now all is revealed. Your curiosity, as well as that of those with you, has been put at ease. + May this server serve well all who happen upon it. + </para> + +<smbconfexample id="ch9-adssdm"> +<title>Samba Domain Member &smb.conf; File for Active Directory Membership</title> +<smbconfcomment>Global parameters</smbconfcomment> +<smbconfsection>[global]</smbconfsection> +<smbconfoption><name>unix charset</name><value>LOCALE</value></smbconfoption> +<smbconfoption><name>workgroup</name><value>LONDON</value></smbconfoption> +<smbconfoption><name>realm</name><value>LONDON.ABMAS.BIZ</value></smbconfoption> +<smbconfoption><name>server string</name><value>Samba 3.0.2</value></smbconfoption> +<smbconfoption><name>security</name><value>ADS</value></smbconfoption> +<smbconfoption><name>username map</name><value>/etc/samba/smbusers</value></smbconfoption> +<smbconfoption><name>log level</name><value>1</value></smbconfoption> +<smbconfoption><name>syslog</name><value>0</value></smbconfoption> +<smbconfoption><name>log file</name><value>/var/log/samba/%m</value></smbconfoption> +<smbconfoption><name>max log size</name><value>50</value></smbconfoption> +<smbconfoption><name>printcap name</name><value>CUPS</value></smbconfoption> +<smbconfoption><name>ldap ssl</name><value>no</value></smbconfoption> +<smbconfoption><name>idmap uid</name><value>10000-20000</value></smbconfoption> +<smbconfoption><name>idmap gid</name><value>10000-20000</value></smbconfoption> +<smbconfoption><name>template primary group</name><value>"Domain Users"</value></smbconfoption> +<smbconfoption><name>template shell</name><value>/bin/bash</value></smbconfoption> +<smbconfoption><name>winbind separator</name><value>+</value></smbconfoption> +<smbconfoption><name>printing</name><value>cups</value></smbconfoption> + +<smbconfsection>[homes]</smbconfsection> +<smbconfoption><name>comment</name><value>Home Directories</value></smbconfoption> +<smbconfoption><name>valid users</name><value>%S</value></smbconfoption> +<smbconfoption><name>read only</name><value>No</value></smbconfoption> +<smbconfoption><name>browseable</name><value>No</value></smbconfoption> + +<smbconfsection>[printers]</smbconfsection> +<smbconfoption><name>comment</name><value>SMB Print Spool</value></smbconfoption> +<smbconfoption><name>path</name><value>/var/spool/samba</value></smbconfoption> +<smbconfoption><name>guest ok</name><value>Yes</value></smbconfoption> +<smbconfoption><name>printable</name><value>Yes</value></smbconfoption> +<smbconfoption><name>browseable</name><value>No</value></smbconfoption> + +<smbconfsection>[print$]</smbconfsection> +<smbconfoption><name>comment</name><value>Printer Drivers</value></smbconfoption> +<smbconfoption><name>path</name><value>/var/lib/samba/drivers</value></smbconfoption> +<smbconfoption><name>admin users</name><value>root, Administrator</value></smbconfoption> +<smbconfoption><name>write list</name><value>root</value></smbconfoption> +</smbconfexample> + + </sect2> + + <sect2> + <title>UNIX/Linux Client Domain Member</title> + + <para><indexterm> + <primary>user credentials</primary> + </indexterm> + So far this chapter has been mainly concerned with the provision of file and print + services for Domain Member servers. However, an increasing number of UNIX/Linux + workstations are being installed that do not act as file or print servers to anyone + other than a single desktop user. The key demand for desktop systems is to be able + to log onto any UNIX/Linux or Windows desktop using the same network user credentials. + </para> + + <para><indexterm> + <primary>Single Sign-On</primary> + <see>SOS</see> + </indexterm> + The ability to use a common set of user credential across a variety of network systems + is generally regarded as a Single Sign-On (SOS) solution. SOS systems are sold by a + large number of vendors and include a range of technologies such as: + </para> + + <itemizedlist> + <listitem><para> + Proxy sign-on + </para></listitem> + + <listitem><para> + Federated directory provisioning + </para></listitem> + + <listitem><para> + Meta-directory server solutions + </para></listitem> + + <listitem><para> + Replacement authentication systems + </para></listitem> + </itemizedlist> + + <para><indexterm> + <primary>Identity management</primary> + </indexterm> + There are really only three solutions that provide integrated authentication and + user Identity management facilities: + </para> + + <itemizedlist> + <listitem><para> + Samba Winbind (free) + </para></listitem> + + <listitem><para> + <ulink url="http://www.padl.com">PADL</ulink> PAM and LDAP Tools (free) + </para></listitem> + + <listitem><para> + <ulink url="http://www.vintela.com">Vintela</ulink> Authentication Services (Commercial) + </para></listitem> + </itemizedlist> + + <para> + The following guidelines are pertinent in respect of the deployment of winbind-based authentication + and Identity resolution with the express purpose of allowing users to log onto UNIX/Linux desktops + using Windows network Domain user credentials (username and password). + </para> + + <para> + You should note that it is possible to use LDAP-based PAM and NSS tools to permit distributed + systems logons (SSO) providing user and group accounts are stored in an LDAP directory. This + provides logon services for UNIX/Linux users, while Windows users obtain their sign-on + support via Samba-3. + </para> + + <para><indexterm> + <primary>Windows Services for UNIX</primary> + <see>SUS</see> + </indexterm> + On the other hand, if the authentication and Identity resolution backend must be provided by + a Windows NT4 style Domain or from an Active Directory Domain that does not have the Microsoft + Windows Services for UNIX (SUS) installed, winbind is your best friend. Specific guidance for these + situations now follows. + </para> + + <para><indexterm> + <primary>PAM</primary> + </indexterm><indexterm> + <primary>Identity resolution</primary> + </indexterm><indexterm> + <primary>NSS</primary> + </indexterm> + To permit users to log onto a Linux system using Windows network credentials, you need to + configure Identity resolution (NSS) and PAM. This means that the basic steps include those + outlined above with the addition of PAM configuration. Given that most workstations (desktop/client) + usually do not need to provide file and print services to a group of users, the configuration + of shares and printers is generally less important. Often this allows the share specifications + to be entirely removed from the &smb.conf; file. That is obviously an administrator decision. + </para> + + <sect3> + <title>NT4 Domain Member</title> + + <para> + The following steps provide a Linux system that users can log onto using + Windows NT4 Domain (or Samba-3) Domain network credentials: + </para> + + <procedure> + <step><para> + Follow the steps outlined in <link linkend="wdcsdm"/> and ensure that + all validation tests function as shown. + </para></step> + + <step><para> + Identify what services users must log onto. On Red Hat Linux, if it is + intended that the user shall be given access to all services, it may be + most expeditious to simply configure the file + <filename>/etc/pam.d/system-auth</filename>. + </para></step> + + <step><para> + Carefully make a backup copy of all PAM configuration files before you + begin making changes. If you break the PAM configuration, please note + that you may need to use an emergency boot process to recover your Linux + system. It is possible to break the ability to log into the system if + PAM files are incorrectly configured. The entire directory + <filename>/etc/pam.d</filename> should be backed up to a safe location. + </para></step> + + <step><para> + If you require only console login support, edit the <filename>/etc/pam.d/login</filename> + so it matches <link linkend="ch9-pamwnbdlogin"/>. + </para></step> + + <step><para> + To provide the ability to log onto the graphical desktop interface, you must edit + the files <filename>gdm</filename> and <filename>xdm</filename> in the + <filename>/etc/pam.d</filename> directory. + </para></step> + + <step><para> + Edit only one file at a time. Carefully validate its operation before attempting + to reboot the machine. + </para></step> + </procedure> + + </sect3> + + <sect3> + <title>ADS Domain Member</title> + + <para> + This procedure should be followed to permit a Linux network client (workstation/desktop) + to permit users to log on using Microsoft Active Directory based user credentials. + </para> + + <procedure> + <step><para> + Follow the steps outlined in <link linkend="adssdm"/> and ensure that + all validation tests function as shown. + </para></step> + + <step><para> + Identify what services users must log onto. On Red Hat Linux, if it is + intended that the user shall be given access to all services, it may be + most expeditious to simply configure the file + <filename>/etc/pam.d/system-auth</filename> as shown in <link linkend="ch9-rhsysauth"/>. + </para></step> + + <step><para> + Carefully make a backup copy of all PAM configuration files before you + begin making changes. If you break the PAM configuration, please note + that you may need to use an emergency boot process to recover your Linux + system. It is possible to break the ability to log into the system if + PAM files are incorrectly configured. The entire directory + <filename>/etc/pam.d</filename> should be backed up to a safe location. + </para></step> + + <step><para> + If you require only console login support, edit the <filename>/etc/pam.d/login</filename> + so it matches <link linkend="ch9-pamwnbdlogin"/>. + </para></step> + + <step><para> + To provide the ability to log onto the graphical desktop interface, you must edit + the files <filename>gdm</filename> and <filename>xdm</filename> in the + <filename>/etc/pam.d</filename> directory. + </para></step> + + <step><para> + Edit only one file at a time. Carefully validate its operation before attempting + to reboot the machine. + </para></step> + </procedure> + + </sect3> + +<example id="ch9-pamwnbdlogin"> +<title>SUSE: PAM <filename>login</filename> Module Using Winbind</title> +<screen> +# /etc/pam.d/login + +#%PAM-1.0 +auth sufficient pam_unix2.so nullok +auth sufficient pam_winbind.so use_first_pass use_authtok +auth required pam_securetty.so +auth required pam_nologin.so +auth required pam_env.so +auth required pam_mail.so +account sufficient pam_unix2.so +account sufficient pam_winbind.so user_first_pass use_authtok +password required pam_pwcheck.so nullok +password sufficient pam_unix2.so nullok use_first_pass use_authtok +password sufficient pam_winbind.so use_first_pass use_authtok +session sufficient pam_unix2.so none +session sufficient pam_winbind.so use_first_pass use_authtok +session required pam_limits.so +</screen> +</example> + +<example id="ch9-pamwbndxdm"> +<title>SUSE: PAM <filename>xdm</filename> Module Using Winbind</title> +<screen> +# /etc/pam.d/gdm (/etc/pam.d/xdm) + +#%PAM-1.0 +auth sufficient pam_unix2.so nullok +auth sufficient pam_winbind.so use_first_pass use_authtok +account sufficient pam_unix2.so +account sufficient pam_winbind.so use_first_pass use_authtok +password sufficient pam_unix2.so +password sufficient pam_winbind.so use_first_pass use_authtok +session sufficient pam_unix2.so +session sufficient pam_winbind.so use_first_pass use_authtok +session required pam_dev perm.so +session required pam_resmgr.so +</screen> +</example> + +<example id="ch9-rhsysauth"> +<title>Red Hat 9: PAM System Authentication File: <filename>/etc/pam.d/system-auth</filename> Module Using Winbind</title> +<screen> +#%PAM-1.0 +auth required /lib/security/$ISA/pam_env.so +auth sufficient /lib/security/$ISA/pam_unix.so likeauth nullok +auth sufficient /lib/security/$ISA/pam_winbind.so use_first_pass +auth required /lib/security/$ISA/pam_deny.so + +account required /lib/security/$ISA/pam_unix.so +account sufficient /lib/security/$ISA/pam_winbind.so use_first_pass + +password required /lib/security/$ISA/pam_cracklib.so retry=3 type= +# Note: The above line is complete. There is nothing following the '=' +password sufficient /lib/security/$ISA/pam_unix.so \ + nullok use_authtok md5 shadow +password sufficient /lib/security/$ISA/pam_winbind.so use_first_pass +password required /lib/security/$ISA/pam_deny.so + +session required /lib/security/$ISA/pam_limits.so +session sufficient /lib/security/$ISA/pam_unix.so +session sufficient /lib/security/$ISA/pam_winbind.so use_first_pass +</screen> +</example> + + </sect2> + + <sect2> + <title>Key Points Learned</title> + + <para> + The addition of UNIX/Linux Samba servers and clients is a common requirement. In this chapter, you + learned how to integrate such servers so that the UID/GID mappings they use can be consistent + across all Domain Member servers. You also discovered how to implement the ability to use Samba + or Windows Domain account credentials to log onto a UNIX/Linux client. + </para> + + <para> + The following are key points noted: + </para> + + <itemizedlist> + <listitem><para> + Domain Controllers are always authoritative for the Domain. + </para></listitem> + + <listitem><para> + Domain Members may have local accounts and must be able to resolve the identity of + Domain user accounts. Domain user account identity must map to a local UID/GID. That + local UID/GID can be stored in LDAP. This way, it is possible to share the IDMAP data + across all Domain Member machines. + </para></listitem> + + <listitem><para> + Resolution of user and group identities on Domain Member machines may be implemented + using direct LDAP services or using winbind. + </para></listitem> + + <listitem><para> + On NSS/PAM enabled UNIX/Linux systems, NSS is responsible for Identity management + and PAM is responsible for authentication of logon credentials (user name and password). + </para></listitem> + </itemizedlist> + + </sect2> + +</sect1> + +<sect1> + <title>Questions and Answers</title> + + <para> + The following questions were obtained from the mailing list and also from private discussions + with Windows network administrators. + </para> + + <qandaset defaultlabel="chap09qa" type="number"> + <qandaentry> + <question> + + <para> + We use NIS for all UNIX accounts. Why do we need winbind? + </para> + + </question> + <answer> + + <para><indexterm> + <primary>NIS</primary> + </indexterm><indexterm> + <primary>encrypted passwords</primary> + </indexterm><indexterm> + <primary>smbpasswd</primary> + </indexterm><indexterm> + <primary>tdbsam</primary> + </indexterm><indexterm> + <primary>passdb backend</primary> + </indexterm><indexterm> + <primary>Winbind</primary> + </indexterm> + You can use NIS for your UNIX accounts. NIS does not store the Windows encrypted + passwords that need to be stored in one of the acceptable passdb backends. + Your choice of backend is limited to <parameter>smbpasswd</parameter> or + <parameter>tdbsam</parameter>. Winbind is needed to handle the resolution of + SIDs from trusted domains to local UID/GID values. + </para> + + <para><indexterm> + <primary>winbind trusted domains only</primary> + </indexterm><indexterm> + <primary>getpwnam()</primary> + </indexterm> + On a Domain Member server, you effectively map Windows Domain users to local users + that are in your NIS database by specifying the <parameter>winbind trusted domains + only</parameter>. This causes user and group account lookups to be routed via + the <command>getpwnam()</command> family of systems calls. On an NIS-enabled client, + this pushes the resolution of users and groups out through NIS. + </para> + + <para> + As a general rule, it is always a good idea to run winbind on all Samba servers. + </para> + + </answer> + </qandaentry> + + <qandaentry> + <question> + + <para> + Our IT management people do not like LDAP, but are looking at Microsoft Active Directory. + Which is better?<indexterm> + <primary>Active Directory</primary> + </indexterm> + </para> + + </question> + <answer> + + <para><indexterm> + <primary>LDAP</primary> + <secondary>server</secondary> + </indexterm><indexterm> + <primary>Kerberos</primary> + </indexterm><indexterm> + <primary>schema</primary> + </indexterm> + Microsoft Active Directory is an LDAP server that is intricately tied to a Kerberos + infrastructure. Most IT managers who object to LDAP do so because of the fact that + an LDAP server is most often supplied as a raw tool that needs to be configured, and + for which the administrator must create the schema, create the administration tools and + devise the backup and recovery facilities in a site dependent manner. LDAP servers + in general are seen as a high-energy, high-risk facility. + </para> + + <para><indexterm> + <primary>management</primary> + </indexterm> + Microsoft Active Directory by comparison is easy to install, configure, and + is supplied with all tools necessary to implement and manage the directory. For sites + that lack a lot of technical competence, Active Directory is a good choice. For sites + that have the technical competence to handle Active Directory well, LDAP is a good + alternative. The real issue that needs to be addressed is what type of solution does + the site want? If management wants a choice to use an alternative, they may want to + consider the options. On the other hand, if management just wants a solution that works, + Microsoft Active Directory is a good solution. + </para> + + </answer> + </qandaentry> + + <qandaentry> + <question> + + <para> + We want to implement a Samba PDC, four Samba BDCs, and 10 Samba servers. Is it possible + to use NIS in place of LDAP? + </para> + + </question> + <answer> + + <para><indexterm> + <primary>NIS</primary> + </indexterm><indexterm> + <primary>LDAP</primary> + </indexterm><indexterm> + <primary>encrypted passwords</primary> + </indexterm><indexterm> + <primary>synchronized</primary> + </indexterm><indexterm> + <primary>secure account password</primary> + </indexterm><indexterm> + <primary>PDC</primary> + </indexterm><indexterm> + <primary>BDC</primary> + </indexterm> + Yes, it is possible to use NIS in place of LDAP, but there may be problems with keeping + the Windows (SMB) encrypted passwords database correctly synchronized across the entire + network. Workstations (Windows client machines) periodically change their Domain + Membership secure account password. How can you keep changes that are on remote BDCs + synchronized on the PDC? + </para> + + <para><indexterm> + <primary>centralized storage</primary> + </indexterm><indexterm> + <primary>management</primary> + </indexterm><indexterm> + <primary>network Identities</primary> + </indexterm> + LDAP is a more elegant solution because it permits centralized storage and management + of all network Identities (user, group and machine accounts) together with all information + Samba needs to provide to network clients and their users. + </para> + + </answer> + </qandaentry> + + <qandaentry> + <question> + + <para> + Are you suggesting that users should not log onto a Domain Member server? If so, why? + </para> + + </question> + <answer> + + <para><indexterm> + <primary>security</primary> + </indexterm><indexterm> + <primary>data</primary> + <secondary>integrity</secondary> + </indexterm><indexterm> + <primary>mapped drives</primary> + </indexterm> + Many UNIX administrators mock the model that the Personal Computer industry has adopted + as normative since the early days of Novell Netware. One may well argue that the old + perception of the necessity to keep users off file and print servers was a result of + fears concerning the security and integrity of data. It was a simple and generally + effective measure to keep users away from servers, except through mapped drives. + </para> + + <para><indexterm> + <primary>user logins</primary> + </indexterm><indexterm> + <primary>risk</primary> + </indexterm><indexterm> + <primary>user errors</primary> + </indexterm><indexterm> + <primary>strategy</primary> + </indexterm><indexterm> + <primary>policy</primary> + </indexterm> + UNIX administrators are fully correct in asserting that UNIX servers and workstations + are identical in terms of the software that is installed. They correctly assert that + in a well secured environment it is safe to store files on a system that has hundreds + of users. But all network administrators must factor into the decision to allow or + reject general user logins to a UNIX system that is principally a file and print + server. One must take account of the risk to operations through simple user errors. + Only then can one begin to appraise the best strategy and adopt a site-specific + policy that best protects the needs of users and of the organization alike. + </para> + + <para><indexterm> + <primary>system level logins</primary> + </indexterm> + From experience, it is my recommendation to keep general system level logins to a + practical minimum and to eliminate them if possible. This should not be taken as a + hard rule, though. The better question is, what works best for the site? + </para> + + </answer> + </qandaentry> + + <qandaentry> + <question> + + <para><indexterm> + <primary>winbind enable local accounts</primary> + </indexterm><indexterm> + <primary>/etc/passwd</primary> + </indexterm><indexterm> + <primary>options list</primary> + </indexterm><indexterm> + <primary>ACL</primary> + </indexterm><indexterm> + <primary>share</primary> + </indexterm> + In my &smb.conf; file, I enabled the parameter <parameter>winbind enable local accounts + </parameter> on all Domain Member servers, but it does not work. The accounts I put in + <filename>/etc/passwd</filename> do not show up in the options list when I try to set an + ACL on a share. What have I done wrong? + </para> + + </question> + <answer> + + <para><indexterm> + <primary>local users</primary> + </indexterm><indexterm> + <primary>local groups</primary> + </indexterm><indexterm> + <primary>UNIX account</primary> + </indexterm><indexterm> + <primary>getpwnam()</primary> + </indexterm><indexterm> + <primary>getgrgid()</primary> + </indexterm><indexterm> + <primary>Identity resolution</primary> + </indexterm><indexterm> + <primary>failure</primary> + </indexterm><indexterm> + <primary>Domain</primary> + </indexterm> + The manual page for this &smb.conf; file parameter clearly says, <quote>This parameter + controls whether or not winbindd will act as a stand in replacement for the various + account management hooks in smb.conf (for example, add user script). If enabled, winbindd + will support the creation of local users and groups as another source of UNIX account + information available via getpwnam() or getgrgid(), etc...</quote> By default this + parameter is already enabled; therefore, the action you are seeing is a result of a failure + of Identity resolution in the Domain. + </para> + + <para><indexterm> + <primary>Domain logons</primary> + </indexterm><indexterm> + <primary>Identity resolution</primary> + </indexterm><indexterm> + <primary>Domain</primary> + <secondary>user</secondary> + </indexterm><indexterm> + <primary>Domain</primary> + <secondary>group</secondary> + </indexterm><indexterm> + <primary>UID</primary> + </indexterm><indexterm> + <primary>GID</primary> + </indexterm> + These are the accounts that are available for Windows network Domain logons. Providing + Identity resolution has been correctly configured on the Domain Controllers, as well as + on Domain Member servers. The Domain user and group identities automatically map + to a valid local UID and GID pair. + </para> + + </answer> + </qandaentry> + + <qandaentry> + <question> + + <para><indexterm> + <primary>trusted domains</primary> + </indexterm><indexterm> + <primary>domain</primary> + <secondary>trusted</secondary> + </indexterm><indexterm> + <primary>winbind trusted domains only</primary> + </indexterm><indexterm> + <primary>domain members</primary> + </indexterm> + We want to ensure that only users from our own domain plus from trusted domains can use our + Samba servers. In the &smb.conf; file on all servers, we have enabled the <parameter>winbind + trusted domains only</parameter> parameter. We now find that users from trusted domains + cannot access our servers, and users from Windows clients that are not domain members + can also access our servers. Is this a Samba bug? + </para> + + </question> + <answer> + + <para><indexterm> + <primary>distributed</primary> + </indexterm><indexterm> + <primary>NIS</primary> + </indexterm><indexterm> + <primary>rsync</primary> + </indexterm><indexterm> + <primary>LDAP</primary> + </indexterm><indexterm> + <primary>winbindd</primary> + </indexterm><indexterm> + <primary>/etc/passwd</primary> + </indexterm> + The manual page for this <parameter>winbind trusted domains only</parameter> parameter says, + <quote>This parameter is designed to allow Samba servers that are members of a Samba controlled + domain to use UNIX accounts distributed vi NIS, rsync, or LDAP as the UIDs for winbindd users + in the hosts primary domain. Therefore, the user <constant>SAMBA\user1</constant> would be + mapped to the account <constant>user1</constant> in <filename>/etc/passwd</filename> instead + of allocating a new UID for him or her.</quote> This would clearly suggest that you are trying + to use this parameter inappropriately. + </para> + + <para><indexterm> + <primary>valid users</primary> + </indexterm> + A far better solution would be to use the <parameter>valid users</parameter> by specifying + precisely the Domain users and groups that should be permitted access to the shares. You could, + for example, set the following parameters: +<screen> +[demoshare] + path = /export/demodata + valid users = @"Domain Users", @"OTHERDOMAIN\Domain Users" +</screen> + </para> + + + </answer> + </qandaentry> + + <qandaentry> + <question> + + <para> + What are the benefits of using LDAP for my Domain Member servers? + </para> + + </question> + <answer> + + <para><indexterm> + <primary>LDAP</primary> + </indexterm><indexterm> + <primary>benefit</primary> + </indexterm><indexterm> + <primary>UID</primary> + </indexterm><indexterm> + <primary>GID</primary> + </indexterm><indexterm> + <primary>Domain Controllers</primary> + </indexterm><indexterm> + <primary>Domain Member servers</primary> + </indexterm><indexterm> + <primary>copy</primary> + </indexterm><indexterm> + <primary>replicate</primary> + </indexterm><indexterm> + <primary>identity</primary> + </indexterm> + The key benefit of using LDAP is that the UID of all users and the GID of all groups + are globally consistent on Domain Controllers as well as on Domain Member servers. + This means that it is possible to copy/replicate files across servers without + loss of identity. + </para> + + <para><indexterm> + <primary>Identity resolution</primary> + </indexterm><indexterm> + <primary>winbind</primary> + </indexterm><indexterm> + <primary>IDMAP backend</primary> + </indexterm><indexterm> + <primary>LDAP</primary> + </indexterm><indexterm> + <primary>Domain Controllers</primary> + </indexterm><indexterm> + <primary>Domain Member</primary> + <secondary>servers</secondary> + </indexterm><indexterm> + <primary>Posix</primary> + </indexterm><indexterm> + <primary>account information</primary> + </indexterm> + When use is made of account Identity resolution via winbind, even when an IDMAP backend + is stored in LDAP, the UID/GID on Domain Member servers is consistent, but differs + from the ID that the user/group has on Domain Controllers. The winbind allocated UID/GID + that is stored in LDAP (or locally) will be in the numeric range specified in the <parameter> + idmap uid/gid</parameter> in the &smb.conf; file. On Domain Controllers, the UID/GID is + that of the Posix value assigned in the LDAP directory as part of the Posix account information. + </para> + + </answer> + </qandaentry> + + <qandaentry> + <question> + + <para> + Is proper DNS operation necessary for Samba-3 plus LDAP? If so, what must I put into + my DNS configuration? + </para> + + </question> + <answer> + + <para><indexterm> + <primary>DNS</primary> + <secondary>configuration</secondary> + </indexterm><indexterm> + <primary>DNS</primary> + <secondary>lookup</secondary> + </indexterm><indexterm> + <primary>hosts</primary> + </indexterm><indexterm> + <primary>/etc/nsswitch.conf</primary> + </indexterm><indexterm> + <primary>NSS</primary> + </indexterm><indexterm> + <primary>/etc/hosts</primary> + </indexterm><indexterm> + <primary>WINS</primary> + <secondary>lookup</secondary> + </indexterm> + Samba depends on correctly functioning resolution of host names to their IP address. Samba + makes no direct DNS lookup calls, but rather redirects all name to address calls via the + <command>getXXXbyXXX()</command> function calls. The configuration of the <constant>hosts</constant> + entry in the NSS <filename>/etc/nsswitch.conf</filename> file determines how the underlying + resolution process is implemented. If the <constant>hosts</constant> entry in your NSS + control file says: +<screen> +hosts: files dns wins +</screen> + This means that a host name lookup first tries the <filename>/etc/hosts</filename>. + If this fails to resolve, it attempts a DNS lookup and if that fails, it tries a + WINS lookup. + </para> + + <para><indexterm> + <primary>NetBIOS</primary> + </indexterm><indexterm> + <primary>TCP/IP</primary> + </indexterm><indexterm> + <primary>name resolution</primary> + </indexterm> + The addition of the WINS-based name lookup makes sense only if NetBIOS over TCP/IP has + been enabled on all Windows clients. Where NetBIOS over TCP/IP has been disabled, DNS + is the preferred name resolution technology. This usually makes most sense when Samba + is a client of an Active Directory Domain, where NetBIOS use has been disabled. In this + case, the Windows 200x auto-registers all locator records it needs with its own DNS + server/s. + </para> + + </answer> + </qandaentry> + + <qandaentry> + <question> + + <para> + Our Windows 2003 Server Active Directory Domain runs with NetBIOS disabled. Can we + use Samba-3 with that configuration? + </para> + + </question> + <answer> + + <para> + Yes. + </para> + + </answer> + </qandaentry> + + <qandaentry> + <question> + + <para><indexterm> + <primary>net</primary> + <secondary>ads</secondary> + <tertiary>join</tertiary> + </indexterm><indexterm> + <primary>net</primary> + <secondary>rpc</secondary> + <tertiary>join</tertiary> + </indexterm> + When I tried to execute <quote>net ads join</quote>, I got no output. It did not work, so + I think that it failed. I then executed <quote>net rpc join</quote> and that worked fine. + That is okay, isn't it? + </para> + + </question> + <answer> + + <para><indexterm> + <primary>Kerberos</primary> + </indexterm><indexterm> + <primary>authentication</primary> + </indexterm> + No. This is not okay. It means that your Samba-3 client has joined the ADS Domain as + a Windows NT4 client, and Samba-3 will not be using Kerberos-based authentication. + </para> + + </answer> + </qandaentry> + + </qandaset> + +</sect1> + +</chapter> |