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diff --git a/docs/htmldocs/samba-bdc.html b/docs/htmldocs/samba-bdc.html new file mode 100644 index 0000000000..e543ac5047 --- /dev/null +++ b/docs/htmldocs/samba-bdc.html @@ -0,0 +1,341 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> +<HTML +><HEAD +><TITLE +>How to Act as a Backup Domain Controller in a Purely Samba Controlled Domain</TITLE +><META +NAME="GENERATOR" +CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ +"><LINK +REL="HOME" +TITLE="SAMBA Project Documentation" +HREF="Samba-HOWTO.html"><LINK +REL="PREVIOUS" +TITLE="How to Configure Samba 2.2 as a Primary Domain Controller" +HREF="samba-pdc.html"><LINK +REL="NEXT" +TITLE="Storing Samba's User/Machine Account information in an LDAP Directory" +HREF="samba-ldap-howto.html"></HEAD +><BODY +CLASS="CHAPTER" +BGCOLOR="#FFFFFF" +TEXT="#000000" +LINK="#0000FF" +VLINK="#840084" +ALINK="#0000FF" +><DIV +CLASS="NAVHEADER" +><TABLE +SUMMARY="Header navigation table" +WIDTH="100%" +BORDER="0" +CELLPADDING="0" +CELLSPACING="0" +><TR +><TH +COLSPAN="3" +ALIGN="center" +>SAMBA Project Documentation</TH +></TR +><TR +><TD +WIDTH="10%" +ALIGN="left" +VALIGN="bottom" +><A +HREF="samba-pdc.html" +ACCESSKEY="P" +>Prev</A +></TD +><TD +WIDTH="80%" +ALIGN="center" +VALIGN="bottom" +></TD +><TD +WIDTH="10%" +ALIGN="right" +VALIGN="bottom" +><A +HREF="samba-ldap-howto.html" +ACCESSKEY="N" +>Next</A +></TD +></TR +></TABLE +><HR +ALIGN="LEFT" +WIDTH="100%"></DIV +><DIV +CLASS="CHAPTER" +><H1 +><A +NAME="SAMBA-BDC">Chapter 13. How to Act as a Backup Domain Controller in a Purely Samba Controlled Domain</H1 +><DIV +CLASS="SECT1" +><H1 +CLASS="SECT1" +><A +NAME="AEN2287">13.1. Prerequisite Reading</H1 +><P +>Before you continue reading in this chapter, please make sure +that you are comfortable with configuring a Samba PDC +as described in the <A +HREF="Samba-PDC-HOWTO.html" +TARGET="_top" +>Samba-PDC-HOWTO</A +>.</P +></DIV +><DIV +CLASS="SECT1" +><H1 +CLASS="SECT1" +><A +NAME="AEN2291">13.2. Background</H1 +><P +>What is a Domain Controller? It is a machine that is able to answer +logon requests from workstations in a Windows NT Domain. Whenever a +user logs into a Windows NT Workstation, the workstation connects to a +Domain Controller and asks him whether the username and password the +user typed in is correct. The Domain Controller replies with a lot of +information about the user, for example the place where the users +profile is stored, the users full name of the user. All this +information is stored in the NT user database, the so-called SAM.</P +><P +>There are two kinds of Domain Controller in a NT 4 compatible Domain: +A Primary Domain Controller (PDC) and one or more Backup Domain +Controllers (BDC). The PDC contains the master copy of the +SAM. Whenever the SAM has to change, for example when a user changes +his password, this change has to be done on the PDC. A Backup Domain +Controller is a machine that maintains a read-only copy of the +SAM. This way it is able to reply to logon requests and authenticate +users in case the PDC is not available. During this time no changes to +the SAM are possible. Whenever changes to the SAM are done on the PDC, +all BDC receive the changes from the PDC.</P +><P +>Since version 2.2 Samba officially supports domain logons for all +current Windows Clients, including Windows 2000 and XP. This text +assumes the domain to be named SAMBA. To be able to act as a PDC, some +parameters in the [global]-section of the smb.conf have to be set:</P +><P +><PRE +CLASS="PROGRAMLISTING" +>workgroup = SAMBA +domain master = yes +domain logons = yes</PRE +></P +><P +>Several other things like a [homes] and a [netlogon] share also may be +set along with settings for the profile path, the users home drive and +others. This will not be covered in this document.</P +></DIV +><DIV +CLASS="SECT1" +><H1 +CLASS="SECT1" +><A +NAME="AEN2299">13.3. What qualifies a Domain Controller on the network?</H1 +><P +>Every machine that is a Domain Controller for the domain SAMBA has to +register the NetBIOS group name SAMBA#1c with the WINS server and/or +by broadcast on the local network. The PDC also registers the unique +NetBIOS name SAMBA#1b with the WINS server. The name type #1b is +normally reserved for the domain master browser, a role that has +nothing to do with anything related to authentication, but the +Microsoft Domain implementation requires the domain master browser to +be on the same machine as the PDC.</P +><DIV +CLASS="SECT2" +><H2 +CLASS="SECT2" +><A +NAME="AEN2302">13.3.1. How does a Workstation find its domain controller?</H2 +><P +>A NT workstation in the domain SAMBA that wants a local user to be +authenticated has to find the domain controller for SAMBA. It does +this by doing a NetBIOS name query for the group name SAMBA#1c. It +assumes that each of the machines it gets back from the queries is a +domain controller and can answer logon requests. To not open security +holes both the workstation and the selected (TODO: How is the DC +chosen) domain controller authenticate each other. After that the +workstation sends the user's credentials (his name and password) to +the domain controller, asking for approval.</P +></DIV +><DIV +CLASS="SECT2" +><H2 +CLASS="SECT2" +><A +NAME="AEN2305">13.3.2. When is the PDC needed?</H2 +><P +>Whenever a user wants to change his password, this has to be done on +the PDC. To find the PDC, the workstation does a NetBIOS name query +for SAMBA#1b, assuming this machine maintains the master copy of the +SAM. The workstation contacts the PDC, both mutually authenticate and +the password change is done.</P +></DIV +></DIV +><DIV +CLASS="SECT1" +><H1 +CLASS="SECT1" +><A +NAME="AEN2308">13.4. Can Samba be a Backup Domain Controller?</H1 +><P +>With version 2.2, no. The native NT SAM replication protocols have +not yet been fully implemented. The Samba Team is working on +understanding and implementing the protocols, but this work has not +been finished for version 2.2.</P +><P +>Can I get the benefits of a BDC with Samba? Yes. The main reason for +implementing a BDC is availability. If the PDC is a Samba machine, +a second Samba machine can be set up to +service logon requests whenever the PDC is down.</P +></DIV +><DIV +CLASS="SECT1" +><H1 +CLASS="SECT1" +><A +NAME="AEN2312">13.5. How do I set up a Samba BDC?</H1 +><P +>Several things have to be done:</P +><P +></P +><UL +><LI +><P +>The domain SID has to be the same on the PDC and the BDC. This used to +be stored in the file private/MACHINE.SID. This file is not created +anymore since Samba 2.2.5 or even earlier. Nowadays the domain SID is +stored in the file private/secrets.tdb. Simply copying the secrets.tdb +from the PDC to the BDC does not work, as the BDC would +generate a new SID for itself and override the domain SID with this +new BDC SID.</P +><P +>To retrieve the domain SID from the PDC or an existing BDC and store it in the +secrets.tdb, execute 'net rpc getsid' on the BDC.</P +></LI +><LI +><P +>The Unix user database has to be synchronized from the PDC to the +BDC. This means that both the /etc/passwd and /etc/group have to be +replicated from the PDC to the BDC. This can be done manually +whenever changes are made, or the PDC is set up as a NIS master +server and the BDC as a NIS slave server. To set up the BDC as a +mere NIS client would not be enough, as the BDC would not be able to +access its user database in case of a PDC failure.</P +></LI +><LI +><P +>The Samba password database in the file private/smbpasswd has to be +replicated from the PDC to the BDC. This is a bit tricky, see the +next section.</P +></LI +><LI +><P +>Any netlogon share has to be replicated from the PDC to the +BDC. This can be done manually whenever login scripts are changed, +or it can be done automatically together with the smbpasswd +synchronization.</P +></LI +></UL +><P +>Finally, the BDC has to be found by the workstations. This can be done +by setting</P +><P +><PRE +CLASS="PROGRAMLISTING" +>workgroup = samba +domain master = no +domain logons = yes</PRE +></P +><P +>in the [global]-section of the smb.conf of the BDC. This makes the BDC +only register the name SAMBA#1c with the WINS server. This is no +problem as the name SAMBA#1c is a NetBIOS group name that is meant to +be registered by more than one machine. The parameter 'domain master = +no' forces the BDC not to register SAMBA#1b which as a unique NetBIOS +name is reserved for the Primary Domain Controller.</P +><DIV +CLASS="SECT2" +><H2 +CLASS="SECT2" +><A +NAME="AEN2329">13.5.1. How do I replicate the smbpasswd file?</H2 +><P +>Replication of the smbpasswd file is sensitive. It has to be done +whenever changes to the SAM are made. Every user's password change is +done in the smbpasswd file and has to be replicated to the BDC. So +replicating the smbpasswd file very often is necessary.</P +><P +>As the smbpasswd file contains plain text password equivalents, it +must not be sent unencrypted over the wire. The best way to set up +smbpasswd replication from the PDC to the BDC is to use the utility +rsync. rsync can use ssh as a transport. ssh itself can be set up to +accept *only* rsync transfer without requiring the user to type a +password.</P +></DIV +></DIV +></DIV +><DIV +CLASS="NAVFOOTER" +><HR +ALIGN="LEFT" +WIDTH="100%"><TABLE +SUMMARY="Footer navigation table" +WIDTH="100%" +BORDER="0" +CELLPADDING="0" +CELLSPACING="0" +><TR +><TD +WIDTH="33%" +ALIGN="left" +VALIGN="top" +><A +HREF="samba-pdc.html" +ACCESSKEY="P" +>Prev</A +></TD +><TD +WIDTH="34%" +ALIGN="center" +VALIGN="top" +><A +HREF="Samba-HOWTO.html" +ACCESSKEY="H" +>Home</A +></TD +><TD +WIDTH="33%" +ALIGN="right" +VALIGN="top" +><A +HREF="samba-ldap-howto.html" +ACCESSKEY="N" +>Next</A +></TD +></TR +><TR +><TD +WIDTH="33%" +ALIGN="left" +VALIGN="top" +>How to Configure Samba 2.2 as a Primary Domain Controller</TD +><TD +WIDTH="34%" +ALIGN="center" +VALIGN="top" +> </TD +><TD +WIDTH="33%" +ALIGN="right" +VALIGN="top" +>Storing Samba's User/Machine Account information in an LDAP Directory</TD +></TR +></TABLE +></DIV +></BODY +></HTML +>
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