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<?xml version="1.0" encoding="iso-8859-1"?>
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<!DOCTYPE chapter PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc">
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<chapter id="ServerType">
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<title>Server Types and Security Modes</title>
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<indexterm><primary>migrate</primary></indexterm>
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<indexterm><primary>security mode</primary></indexterm>
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This chapter provides information regarding the types of server that Samba may be configured to be. A
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Microsoft network administrator who wishes to migrate to or use Samba will want to know the meaning, within a
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Samba context, of terms familiar to the MS Windows administrator. This means that it is essential also to
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define how critical security modes function before we get into the details of how to configure the server
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This chapter provides an overview of the security modes of which Samba is capable and how they relate to MS
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Windows servers and clients.
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A question often asked is, <quote>Why would I want to use Samba?</quote> Most chapters contain a section that
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highlights features and benefits. We hope that the information provided will help to answer this question. Be
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warned though, we want to be fair and reasonable, so not all features are positive toward Samba. The benefit
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may be on the side of our competition.
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<title>Features and Benefits</title>
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Two men were walking down a dusty road, when one suddenly kicked up a small red stone. It
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hurt his toe and lodged in his sandal. He took the stone out and cursed it with a passion
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and fury befitting his anguish. The other looked at the stone and said, <quote>This is a garnet.
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I can turn that into a precious gem and some day it will make a princess very happy!</quote>
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The moral of this tale: Two men, two very different perspectives regarding the same stone.
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Like it or not, Samba is like that stone. Treat it the right way and it can bring great
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pleasure, but if you are forced to use it and have no time for its secrets, then it can be
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a source of discomfort.
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<indexterm><primary>UNIX</primary><secondary>server</secondary></indexterm>
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<indexterm><primary>interoperability</primary></indexterm>
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Samba started out as a project that sought to provide interoperability for MS Windows 3.x
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clients with a UNIX server. It has grown up a lot since its humble beginnings and now provides
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features and functionality fit for large-scale deployment. It also has some warts. In sections
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like this one, we tell of both.
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So, what are the benefits of the features mentioned in this chapter?
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<indexterm><primary>domain</primary><secondary>controller</secondary></indexterm>
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Samba-3 can replace an MS Windows NT4 domain controller.
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<indexterm><primary>active directory</primary></indexterm>
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Samba-3 offers excellent interoperability with MS Windows NT4-style
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domains as well as natively with Microsoft Active Directory domains.
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<indexterm><primary>interdomain</primary><secondary>trustrs</secondary></indexterm>
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Samba-3 permits full NT4-style interdomain trusts.
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<indexterm><primary>authentication</primary></indexterm>
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<indexterm><primary>security</primary><secondary>modes</secondary></indexterm>
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Samba has security modes that permit more flexible authentication
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than is possible with MS Windows NT4 domain controllers.
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<indexterm><primary>account</primary><secondary>database</secondary><tertiary>backends</tertiary></indexterm>
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<indexterm><primary>encrypted</primary></indexterm>
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Samba-3 permits use of multiple concurrent account database backends.
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(Encrypted passwords that are stored in the account database are in
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formats that are unique to Windows networking).
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<indexterm><primary>replicated</primary></indexterm>
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The account database backends can be distributed
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and replicated using multiple methods. This gives Samba-3
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greater flexibility than MS Windows NT4 and in many cases a
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significantly higher utility than Active Directory domains
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with MS Windows 200x.
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<title>Server Types</title>
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<indexterm><primary>Server Type</primary></indexterm>
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Administrators of Microsoft networks often refer to three different types of servers:
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<listitem><para>Domain Controller</para>
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<listitem><para>Primary Domain Controller (PDC)</para></listitem>
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<listitem><para>Backup Domain Controller (BDC)</para></listitem>
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<listitem><para>ADS Domain Controller</para></listitem>
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<listitem><para>Domain Member Server</para>
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<listitem><para>Active Directory Domain Server</para></listitem>
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<listitem><para>NT4 Style Domain Domain Server</para></listitem>
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<listitem><para>Standalone Server</para></listitem>
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<indexterm><primary>domain</primary><secondary>control</secondary></indexterm>
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<indexterm><primary>domain</primary><secondary>member</secondary></indexterm>
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<indexterm><primary>domain control</primary><secondary>primary</secondary></indexterm>
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<indexterm><primary>domain control</primary><secondary>backup</secondary></indexterm>
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The chapters covering domain control (<link linkend="samba-pdc">Domain Control</link>),
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backup domain control (<link linkend="samba-bdc">Backup Domain Control</link>), and
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domain membership (<link linkend="domain-member">Domain Membership</link>) provide
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pertinent information regarding Samba configuration for each of these server roles.
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You are strongly encouraged to become intimately familiar with these chapters because
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they lay the foundation for deployment of Samba domain security.
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<indexterm><primary>standalone</primary></indexterm>
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A Standalone server is autonomous in respect of the source of its account backend.
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Refer to <link linkend="StandAloneServer">Standalone Servers</link> to gain a wider appreciation
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of what is meant by a server being configured as a <emphasis>standalone</emphasis> server.
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<title>Samba Security Modes</title>
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<indexterm><primary>Security Mode</primary></indexterm>
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<indexterm><primary>security</primary></indexterm>
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In this section, the function and purpose of Samba's security modes are described. An accurate understanding of
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how Samba implements each security mode as well as how to configure MS Windows clients for each mode will
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significantly reduce user complaints and administrator heartache.
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<indexterm><primary>Server Message Block</primary><see>SMB</see></indexterm>
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<indexterm><primary>Common Internet Filesystem</primary><see>CIFS</see></indexterm>
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Microsoft Windows networking uses a protocol that was originally called the Server Message Block (SMB)
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protocol. Since some time around 1996 the protocol has been better known as the Common Internet Filesystem
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<indexterm><primary>security levels</primary></indexterm>
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<indexterm><primary>security modes</primary></indexterm>
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<indexterm><primary>user-level</primary></indexterm>
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<indexterm><primary>share-level</primary></indexterm>
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In the SMB/CIFS networking world, there are only two types of security: <emphasis>user-level</emphasis> and
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<emphasis>share level</emphasis>. We refer to these collectively as <emphasis>security levels</emphasis>. In
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implementing these two security levels, Samba provides flexibilities that are not available with MS Windows
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NT4/200x servers. In fact, Samba implements <emphasis>share-level</emphasis> security only one way, but has
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four ways of implementing <emphasis>user-level</emphasis> security. Collectively, we call the Samba
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implementations of the security levels <emphasis>security modes</emphasis>. They are known as
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<emphasis>share</emphasis>, <emphasis>user</emphasis>, <emphasis>domain</emphasis>, <emphasis>ADS</emphasis>,
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and <emphasis>server</emphasis> modes. They are documented in this chapter.
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An SMB server informs the client, at the time of a session setup, the security level the server is running.
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There are two options: share-level and user-level. Which of these two the client receives affects the way the
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client then tries to authenticate itself. It does not directly affect (to any great extent) the way the Samba
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server does security. This may sound strange, but it fits in with the client/server approach of SMB. In SMB
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everything is initiated and controlled by the client, and the server can only tell the client what is
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available and whether an action is allowed.
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The term <literal>client</literal> refers to all agents whether it is a Windows workstation, a Windows server,
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another Samba server, or any vanilla SMB or CIFS client application (e.g., <command>smbclient</command>) that
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make use of services provided by an SMB/CIFS server.
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<title>User Level Security</title>
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<indexterm><primary>user-level</primary></indexterm>
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We describe user-level security first because its simpler. In user-level security, the client sends a session
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setup request directly following protocol negotiation. This request provides a username and password. The
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server can either accept or reject that username/password combination. At this stage the server has no idea
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what share the client will eventually try to connect to, so it can't base the
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<emphasis>accept/reject</emphasis> on anything other than:
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<listitem><para>the username/password.</para></listitem>
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<listitem><para>the name of the client machine.</para></listitem>
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<indexterm><primary>credentials</primary></indexterm>
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If the server accepts the username/password credentials, the client expects to be able to mount shares (using
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a <emphasis>tree connection</emphasis>) without further specifying a password. It expects that all access
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rights will be as the username/password credentials set that was specified in the initial <emphasis>session
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<indexterm><primary>session setup</primary></indexterm>
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It is also possible for a client to send multiple <emphasis>session setup</emphasis>
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requests. When the server responds, it gives the client a <emphasis>uid</emphasis> to use
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as an authentication tag for that username/password. The client can maintain multiple
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authentication contexts in this way (WinDD is an example of an application that does this).
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<indexterm><primary>LanManager</primary></indexterm>
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<indexterm><primary>case-preserving</primary></indexterm>
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<indexterm><primary>case-insensitive</primary></indexterm>
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<indexterm><primary>upper-case</primary></indexterm>
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<indexterm><primary>lower-case</primary></indexterm>
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Windows networking user account names are case-insensitive, meaning that upper-case and lower-case characters
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in the account name are considered equivalent. They are said to be case-preserving, but not case significant.
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Windows and LanManager systems previous to Windows NT version 3.10 have case-insensitive passwords that were
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not necessarily case-preserving. All Windows NT family systems treat passwords as case-preserving and
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<title>Example Configuration</title>
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The &smb.conf; parameter that sets user-level security is:
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<smbconfoption name="security">user</smbconfoption>
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</smbconfblock></para>
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This is the default setting since Samba-2.2.x.
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<title>Share-Level Security</title>
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<indexterm><primary>share-level</primary></indexterm>
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<indexterm><primary>mount</primary></indexterm>
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In share-level security, the client authenticates itself separately for each share. It sends a password along
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with each tree connection request (share mount), but it does not explicitly send a username with this
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operation. The client expects a password to be associated with each share, independent of the user. This means
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that Samba has to work out what username the client probably wants to use,
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because the username is not explicitly sent to the SMB server. Some commercial SMB servers such as NT actually associate passwords directly with shares
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in share-level security, but Samba always uses the UNIX authentication scheme where it is a username/password
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pair that is authenticated, not a share/password pair.
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To understand the MS Windows networking parallels, think in terms of MS Windows 9x/Me where you can create a
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shared folder that provides read-only or full access, with or without a password.
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Many clients send a session setup request even if the server is in share-level security. They normally send a valid
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username but no password. Samba records this username in a list of possible usernames. When the client then
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issues a tree connection request, it also adds to this list the name of the share they try to connect to (useful for
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home directories) and any users listed in the <smbconfoption name="user"/> parameter in the &smb.conf; file.
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The password is then checked in turn against these possible usernames. If a match is found, then the client is
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authenticated as that user.
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<indexterm><primary>name service switch</primary><see>NSS</see></indexterm>
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<indexterm><primary>/etc/passwd</primary></indexterm>
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<indexterm><primary>nsswitch.conf</primary></indexterm>
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Where the list of possible user names is not provided, Samba makes a UNIX system call to find the user
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account that has a password that matches the one provided from the standard account database. On a system that
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has no name service switch (NSS) facility, such lookups will be from the <filename>/etc/passwd</filename>
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database. On NSS enabled systems, the lookup will go to the libraries that have been specified in the
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<filename>nsswitch.conf</filename> file. The entries in that file in which the libraries are specified are:
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passwd: files nis ldap
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shadow: files nis ldap
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group: files nis ldap
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<indexterm><primary>/etc/passwd</primary></indexterm>
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<indexterm><primary>/etc/group</primary></indexterm>
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<indexterm><primary>NIS</primary></indexterm>
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In the example shown here (not likely to be used in practice) the lookup will check
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<filename>/etc/passwd</filename> and <filename>/etc/group</filename>, if not found it will check NIS, then
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<title>Example Configuration</title>
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The &smb.conf; parameter that sets share-level security is:
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<smbconfoption name="security">share</smbconfoption>
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</smbconfblock></para>
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<title>Domain Security Mode (User-Level Security)</title>
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<indexterm><primary>domain</primary><secondary>controllers</secondary></indexterm>
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<indexterm><primary>security</primary><secondary>controllers</secondary></indexterm>
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<indexterm><primary>PDC</primary></indexterm>
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<indexterm><primary>BDC</primary></indexterm>
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<indexterm><primary>logon</primary></indexterm>
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<indexterm><primary>authentication</primary></indexterm>
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Domain security provides a mechanism for storing all user and group accounts in a central, shared, account
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repository. The centralized account repository is shared between domain (security) controllers. Servers that
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act as domain controllers provide authentication and validation services to all machines that participate in
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the security context for the domain. A primary domain controller (PDC) is a server that is responsible for
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maintaining the integrity of the security account database. Backup domain controllers (BDCs) provide only domain
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logon and authentication services. Usually, BDCs will answer network logon requests more responsively than
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<indexterm><primary>domain member</primary></indexterm>
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<indexterm><primary>trust account</primary></indexterm>
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<indexterm><primary>trust</primary><secondary>account</secondary></indexterm>
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<indexterm><primary>domain</primary><secondary>security</secondary></indexterm>
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<indexterm><primary>domain</primary><secondary>controller</secondary></indexterm>
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When Samba is operating in <smbconfoption name="security">domain</smbconfoption> mode, the Samba server has a
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domain security trust account (a machine account) and causes all authentication requests to be passed through
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to the domain controllers. In other words, this configuration makes the Samba server a domain member server,
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even when it is in fact acting as a domain controller. All machines that participate in domain security must
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have a machine account in the security database.
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<indexterm><primary>account</primary><secondary>database</secondary></indexterm>
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<indexterm><primary>machine</primary><secondary>account</secondary></indexterm>
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<indexterm><primary>NetBIOS</primary><secondary>name</secondary></indexterm>
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<indexterm><primary>NetBIOS</primary></indexterm>
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Within the domain security environment, the underlying security architecture uses user-level security. Even
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machines that are domain members must authenticate on startup. The machine account consists of an account
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entry in the accounts database, the name of which is the NetBIOS name of the machine and of which the password
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is randomly generated and known to both the domain controllers and the member machine. If the machine account
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cannot be validated during startup, users will not be able to log on to the domain using this machine because
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it cannot be trusted. The machine account is referred to as a machine trust account.
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There are three possible domain member configurations:
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<listitem><para>Primary domain controller (PDC) - of which there is one per domain.</para></listitem>
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<listitem><para>Backup domain controller (BDC) - of which there can be any number per domain.</para></listitem>
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<listitem><para>Domain member server (DMS) - of which there can be any number per domain.</para></listitem>
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<indexterm><primary>DMS</primary></indexterm>
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We will discuss each of these in separate chapters. For now, we are most interested in basic DMS
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<title>Example Configuration</title>
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Samba as a Domain Member Server
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<indexterm><primary>server type</primary><secondary>domain member</secondary></indexterm>
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This method involves addition of the following parameters in the &smb.conf; file:
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<smbconfoption name="security">domain</smbconfoption>
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<smbconfoption name="workgroup">&example.workgroup;</smbconfoption>
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In order for this method to work, the Samba server needs to join the MS Windows NT
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security domain. This is done as follows:
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<indexterm><primary>net</primary><secondary>rpc</secondary></indexterm>
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<indexterm><primary>Domain Member</primary><secondary>joining</secondary></indexterm>
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<step><para>On the MS Windows NT domain controller, using
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the Server Manager, add a machine account for the Samba server.
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<step><para>On the UNIX/Linux system execute:</para>
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<para><screen>&rootprompt;<userinput>net rpc join -U administrator%password</userinput></screen></para>
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<indexterm><primary>smbpasswd</primary></indexterm>
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Samba-2.2.4 and later Samba 2.2.x series releases can autojoin a Windows NT4-style domain just by executing:
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&rootprompt;<userinput>smbpasswd -j <replaceable>DOMAIN_NAME</replaceable> -r <replaceable>PDC_NAME</replaceable> \
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-U Administrator%<replaceable>password</replaceable></userinput>
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<indexterm><primary>net</primary><secondary>rpc</secondary><tertiary>join</tertiary></indexterm>
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Samba-3 can do the same by executing:
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&rootprompt;<userinput>net rpc join -U Administrator%<replaceable>password</replaceable></userinput>
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It is not necessary with Samba-3 to specify the <replaceable>DOMAIN_NAME</replaceable> or the
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<replaceable>PDC_NAME</replaceable>, as it figures this out from the &smb.conf; file settings.
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<indexterm><primary>invalid shell</primary></indexterm>
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<indexterm><primary>/etc/passwd</primary></indexterm>
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<indexterm><primary>/bin/false</primary></indexterm>
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Use of this mode of authentication requires there to be a standard UNIX account for each user in order to
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assign a UID once the account has been authenticated by the Windows domain controller. This account can be
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blocked to prevent logons by clients other than MS Windows through means such as setting an invalid shell in
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the <filename>/etc/passwd</filename> entry. The best way to allocate an invalid shell to a user account is to
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set the shell to the file <filename>/bin/false</filename>.
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<indexterm><primary>PDC</primary></indexterm>
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<indexterm><primary>BDC</primary></indexterm>
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Domain controllers can be located anywhere that is convenient. The best advice is to have a BDC on every
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physical network segment, and if the PDC is on a remote network segment the use of WINS (see <link
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linkend="NetworkBrowsing">Network Browsing</link> for more information) is almost essential.
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An alternative to assigning UIDs to Windows users on a Samba member server is presented in <link
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linkend="winbind">Winbind</link>, <link linkend="winbind">Winbind: Use of Domain Accounts</link>.
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For more information regarding domain membership, <link linkend="domain-member">Domain Membership</link>.
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<title>ADS Security Mode (User-Level Security)</title>
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<indexterm><primary>ADS</primary></indexterm>
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<indexterm><primary>native mode</primary></indexterm>
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Both Samba-2.2, and Samba-3 can join an Active Directory domain using NT4 style RPC based security. This is
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possible if the domain is run in native mode. Active Directory in native mode perfectly allows NT4-style
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domain members. This is contrary to popular belief.
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If you are using Active Directory, starting with Samba-3 you can join as a native AD member. Why would you
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want to do that? Your security policy might prohibit the use of NT-compatible authentication protocols. All
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your machines are running Windows 2000 and above and all use Kerberos. In this case, Samba, as an NT4-style
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domain, would still require NT-compatible authentication data. Samba in AD-member mode can accept Kerberos
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<indexterm><primary>realm</primary></indexterm>
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<indexterm><primary>mixed mode</primary></indexterm>
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Sites that use Microsoft Windows active directory services (ADS) should be aware of the significance of the
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terms: <literal>native mode</literal> and <literal>mixed mode</literal> ADS operation. The term
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<literal>realm</literal> is used to describe a Kerberos-based security architecture (such as is used by
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<title>Example Configuration</title>
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<smbconfoption name="realm">your.kerberos.REALM</smbconfoption>
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<smbconfoption name="security">ADS</smbconfoption>
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</smbconfblock></para>
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The following parameter may be required:
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<smbconfoption name="password server">your.kerberos.server</smbconfoption>
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</smbconfblock></para>
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Please refer to <link linkend="domain-member">Domain Membership</link>, and <link linkend="ads-member">Samba
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ADS Domain Membership</link> for more information regarding this configuration option.
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<title>Server Security (User Level Security)</title>
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Server security mode is left over from the time when Samba was not capable of acting
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as a domain member server. It is highly recommended not to use this feature. Server
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security mode has many drawbacks that include:
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<listitem><para>Potential account lockout on MS Windows NT4/200x password servers.</para></listitem>
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<listitem><para>Lack of assurance that the password server is the one specified.</para></listitem>
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<listitem><para>Does not work with Winbind, which is particularly needed when storing profiles remotely.</para></listitem>
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<listitem><para>This mode may open connections to the password server and keep them open for extended periods.</para></listitem>
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<listitem><para>Security on the Samba server breaks badly when the remote password server suddenly shuts down.</para></listitem>
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<listitem><para>With this mode there is NO security account in the domain that the password server belongs to for the Samba server.</para></listitem>
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<indexterm><primary>session setup</primary></indexterm>
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<indexterm><primary>SMB</primary></indexterm>
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In server security mode the Samba server reports to the client that it is in user-level security. The client
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then does a session setup as described earlier. The Samba server takes the username/password that the client
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sends and attempts to log into the <smbconfoption name="password server"/> by sending exactly the same
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username/password that it got from the client. If that server is in user-level security and accepts the
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password, then Samba accepts the client's connection. This parameter allows the Samba server to use another
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SMB server as the <smbconfoption name="password server"/>.
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<indexterm><primary>security level</primary></indexterm>
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<indexterm><primary>encryption</primary></indexterm>
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You should also note that at the start of all this, when the server tells the client
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what security level it is in, it also tells the client if it supports encryption. If it
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does, it supplies the client with a random cryptkey. The client will then send all
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passwords in encrypted form. Samba supports this type of encryption by default.
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The parameter <smbconfoption name="security">server</smbconfoption> means that Samba reports to clients that
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it is running in <emphasis>user mode</emphasis> but actually passes off all authentication requests to another
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user mode server. This requires an additional parameter <smbconfoption name="password server"/> that points to
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the real authentication server. The real authentication server can be another Samba server, or it can be a
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Windows NT server, the latter being natively capable of encrypted password support.
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<indexterm><primary>password server</primary></indexterm>
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<indexterm><primary>workgroup</primary></indexterm>
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When Samba is running in <emphasis>server security mode</emphasis>, it is essential that the parameter
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<emphasis>password server</emphasis> is set to the precise NetBIOS machine name of the target authentication
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server. Samba cannot determine this from NetBIOS name lookups because the choice of the target authentication
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server is arbitrary and cannot be determined from a domain name. In essence, a Samba server that is in
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<emphasis>server security mode</emphasis> is operating in what used to be known as workgroup mode.
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<title>Example Configuration</title>
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Using MS Windows NT as an Authentication Server
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This method involves the additions of the following parameters in the &smb.conf; file:
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<smbconfoption name="encrypt passwords">Yes</smbconfoption>
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<smbconfoption name="security">server</smbconfoption>
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<smbconfoption name="password server">"NetBIOS_name_of_a_DC"</smbconfoption>
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</smbconfblock></para>
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There are two ways of identifying whether or not a username and password pair is valid.
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One uses the reply information provided as part of the authentication messaging
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process, the other uses just an error code.
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<indexterm><primary>bogus</primary></indexterm>
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<indexterm><primary>lockout</primary></indexterm>
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The downside of this mode of configuration is that for security reasons Samba
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will send the password server a bogus username and a bogus password, and if the remote
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server fails to reject the bogus username and password pair, then an alternative mode of
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identification or validation is used. Where a site uses password lockout, after a
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certain number of failed authentication attempts, this will result in user lockouts.
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Use of this mode of authentication requires a standard UNIX account for the user.
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This account can be blocked to prevent logons by non-SMB/CIFS clients.
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<title>Password Checking</title>
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MS Windows clients may use encrypted passwords as part of a challenge/response
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authentication model (a.k.a. NTLMv1 and NTLMv2) or alone, or clear-text strings for simple
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password-based authentication. It should be realized that with the SMB protocol,
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the password is passed over the network either in plaintext or encrypted, but
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not both in the same authentication request.
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<indexterm><primary>encrypted passwords</primary></indexterm>
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<indexterm><primary>encrypted</primary></indexterm>
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When encrypted passwords are used, a password that has been entered by the user
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is encrypted in two ways:
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<listitem><para>An MD4 hash of the unicode of the password
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string. This is known as the NT hash.
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<listitem><para>The password is converted to uppercase,
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and then padded or truncated to 14 bytes. This string is
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then appended with 5 bytes of NULL characters and split to
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form two 56-bit DES keys to encrypt a "magic" 8-byte value.
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The resulting 16 bytes form the LanMan hash.
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<indexterm><primary>plain-text</primary><secondary>passwords</secondary></indexterm>
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MS Windows 95 pre-service pack 1 and MS Windows NT versions 3.x and version 4.0 pre-service pack 3 will use
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either mode of password authentication. All versions of MS Windows that follow these versions no longer
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support plain-text passwords by default.
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<indexterm><primary>cached</primary><secondary>password</secondary></indexterm>
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MS Windows clients have a habit of dropping network mappings that have been idle
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for 10 minutes or longer. When the user attempts to use the mapped drive
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connection that has been dropped, the client re-establishes the connection using
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a cached copy of the password.
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When Microsoft changed the default password mode, support was dropped for caching
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of the plaintext password. This means that when the registry parameter is changed
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to re-enable use of plaintext passwords, it appears to work, but when a dropped
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service connection mapping attempts to revalidate, this will fail if the remote
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authentication server does not support encrypted passwords. It is definitely not
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a good idea to re-enable plaintext password support in such clients.
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The following parameters can be used to work around the issue of Windows 9x/Me clients
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uppercasing usernames and passwords before transmitting them to the SMB server
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when using clear-text authentication:
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<smbconfoption name="password level"><replaceable>integer</replaceable></smbconfoption>
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<smbconfoption name="username level"><replaceable>integer</replaceable></smbconfoption>
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By default Samba will convert to lowercase the username before attempting to lookup the user
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in the database of local system accounts. Because UNIX usernames conventionally
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only contain lowercase characters, the <smbconfoption name="username-level"/> parameter
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<indexterm><primary>clear-text</primary></indexterm>
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However, passwords on UNIX systems often make use of mixed-case characters. This means that in order for a
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user on a Windows 9x/Me client to connect to a Samba server using clear-text authentication, the
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<smbconfoption name="password level"/> must be set to the maximum number of uppercase letters that
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<emphasis>could</emphasis> appear in a password. Note that if the Server OS uses the traditional DES version
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of crypt(), a <smbconfoption name="password level"/> of 8 will result in case-insensitive passwords as seen
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from Windows users. This will also result in longer login times because Samba has to compute the permutations
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of the password string and try them one by one until a match is located (or all combinations fail).
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The best option to adopt is to enable support for encrypted passwords wherever
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Samba is used. Most attempts to apply the registry change to re-enable plaintext
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passwords will eventually lead to user complaints and unhappiness.
724
<title>Common Errors</title>
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We all make mistakes. It is okay to make mistakes, as long as they are made in the right places
728
and at the right time. A mistake that causes lost productivity is seldom tolerated; however, a mistake
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made in a developmental test lab is expected.
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Here we look at common mistakes and misapprehensions that have been the subject of discussions
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on the Samba mailing lists. Many of these are avoidable by doing your homework before attempting
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a Samba implementation. Some are the result of a misunderstanding of the English language,
736
which has many phrases that are potentially vague and may be highly confusing
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to those for whom English is not their native tongue.
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<title>What Makes Samba a Server?</title>
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To some, the nature of the Samba security mode is obvious, but entirely
745
wrong all the same. It is assumed that <smbconfoption name="security">server</smbconfoption> means that Samba
746
will act as a server. Not so! This setting means that Samba will <emphasis>try</emphasis>
747
to use another SMB server as its source for user authentication alone.
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Samba is a server regardless of which security mode is chosen. When Samba is used outside of a domain security
752
context, it is best to leave the security mode at the default setting. By default Samba-3 uses user-mode
759
<title>What Makes Samba a Domain Controller?</title>
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<indexterm><primary>server-mode</primary></indexterm>
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The &smb.conf; parameter <smbconfoption name="security">domain</smbconfoption> does not really make Samba behave
764
as a domain controller. This setting means we want Samba to be a domain member. See <link
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linkend="samba-pdc">Samba as a PDC</link> for more information.
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<title>What Makes Samba a Domain Member?</title>
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Guess! So many others do. But whatever you do, do not think that <smbconfoption name="security">user</smbconfoption>
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makes Samba act as a domain member. Read the manufacturer's manual before the warranty expires. See
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<link linkend="domain-member">Domain Membership</link>, for more information.
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<title>Constantly Losing Connections to Password Server</title>
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Why does server_validate() simply give up rather than re-establish its connection to the
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password server? Though I am not fluent in the SMB protocol, perhaps the cluster server
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process passes along to its client workstation the session key it receives from the password
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server, which means the password hashes submitted by the client would not work on a subsequent
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connection whose session key would be different. So server_validate() must give up.
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Indeed. That's why <smbconfoption name="security">server</smbconfoption>
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is at best a nasty hack. Please use <smbconfoption name="security">domain</smbconfoption>;
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<smbconfoption name="security">server</smbconfoption> mode is also known as pass-through authentication.
802
<title>Stand-alone Server is converted to Domain Controller &smbmdash; Now User accounts don't work</title>
805
When I try to log in to the DOMAIN, the eventlog shows <emphasis>tried credentials DOMAIN/username; effective
806
credentials SERVER/username</emphasis>
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Usually this is due to a user or machine account being created before the Samba server is configured to be a
811
domain controller. Accounts created before the server becomes a domain controller will be
812
<emphasis>local</emphasis> accounts and authenticated as what looks like a member in the SERVER domain, much
813
like local user accounts in Windows 2000 and later. Accounts created after the Samba server becomes a domain
814
controller will be <emphasis>domain</emphasis> accounts and will be authenticated as a member of the DOMAIN
819
This can be verified by issuing the command <command>pdbedit -L -v username</command>. If this reports DOMAIN
820
then the account is a domain account, if it reports SERVER then the account is a local account.
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The easiest way to resolve this is to remove and recreate the account; however this may cause problems with
825
established user profiles. You can also use <command>pdbedit -u username -I DOMAIN</command>. You may also
826
need to change the User SID and Primary Group SID to match the domain.
added
removed
docs-xml/Samba3-HOWTO/TOSHARG-ServerType.xml
