<chapter id="domain-security">

<chapterinfo>
	<author>
		<firstname>Jeremy</firstname><surname>Allison</surname>
		<affiliation>
			<orgname>Samba Team</orgname>
			<address>
				<email>samba@samba.org</email>
			</address>
		</affiliation>
	</author>
	<author>
		<firstname>Jerry</firstname><surname>Carter</surname>
		<affiliation>
			<orgname>Samba Team</orgname>
			<address>
				<email>jerry@samba.org</email>
			</address>
		</affiliation>
	</author>
	
		
	<pubdate>16 Apr 2001</pubdate>
</chapterinfo>


<title>security = domain in Samba 2.x</title>

<sect1>

	<title>Joining an NT Domain with Samba 2.2</title>

	<para>Assume you have a Samba 2.x server with a NetBIOS name of 
	<constant>SERV1</constant> and are joining an NT domain called
	<constant>DOM</constant>, which has a PDC with a NetBIOS name
	of <constant>DOMPDC</constant> and two backup domain controllers 
	with NetBIOS names <constant>DOMBDC1</constant> and <constant>DOMBDC2
	</constant>.</para>

	<para>In order to join the domain, first stop all Samba daemons 
	and run the command:</para>

	<para><prompt>root# </prompt><userinput>smbpasswd -j DOM -r DOMPDC
	-U<replaceable>Administrator%password</replaceable></userinput></para>

	<para>as we are joining the domain DOM and the PDC for that domain 
	(the only machine that has write access to the domain SAM database) 
	is DOMPDC. The <replaceable>Administrator%password</replaceable> is 
	the login name and password for an account which has the necessary 
	privilege to add machines to the domain.  If this is successful 
	you will see the message:</para>

	<para><computeroutput>smbpasswd: Joined domain DOM.</computeroutput>
	</para>

	<para>in your terminal window. See the <ulink url="smbpasswd.8.html">
	smbpasswd(8)</ulink> man page for more details.</para>
	
	<para>There is existing development code to join a domain
	without having to create the machine trust account on the PDC
	beforehand.  This code will hopefully be available soon
	in release branches as well.</para>

	<para>This command goes through the machine account password 
	change protocol, then writes the new (random) machine account 
	password for this Samba server into a file in the same directory 
	in which an smbpasswd file would be stored - normally :</para>

	<para><filename>/usr/local/samba/private</filename></para>

	<para>In Samba 2.0.x, the filename looks like this:</para>

	<para><filename><replaceable>&lt;NT DOMAIN NAME&gt;</replaceable>.<replaceable>&lt;Samba 
	Server Name&gt;</replaceable>.mac</filename></para>
	
	<para>The <filename>.mac</filename> suffix stands for machine account 
	password file. So in our example above, the file would be called:</para>

	<para><filename>DOM.SERV1.mac</filename></para>

	<para>In Samba 2.2, this file has been replaced with a TDB 
	(Trivial Database) file named <filename>secrets.tdb</filename>.
	</para>


	<para>This file is created and owned by root and is not 
	readable by any other user. It is the key to the domain-level 
	security for your system, and should be treated as carefully 
	as a shadow password file.</para>

	<para>Now, before restarting the Samba daemons you must 
	edit your <ulink url="smb.conf.5.html"><filename>smb.conf(5)</filename>
	</ulink> file to tell Samba it should now use domain security.</para>
	
	<para>Change (or add) your <ulink url="smb.conf.5.html#SECURITY">
	<parameter>security =</parameter></ulink> line in the [global] section 
	of your smb.conf to read:</para>

	<para><command>security = domain</command></para>

	<para>Next change the <ulink url="smb.conf.5.html#WORKGROUP"><parameter>
	workgroup =</parameter></ulink> line in the [global] section to read: </para>

	<para><command>workgroup = DOM</command></para>

	<para>as this is the name of the domain we are joining. </para>

	<para>You must also have the parameter <ulink url="smb.conf.5.html#ENCRYPTPASSWORDS">
	<parameter>encrypt passwords</parameter></ulink> set to <constant>yes
	</constant> in order for your users to authenticate to the NT PDC.</para>

	<para>Finally, add (or modify) a <ulink url="smb.conf.5.html#PASSWORDSERVER">
	<parameter>password server =</parameter></ulink> line in the [global]
	section to read: </para>

	<para><command>password server = DOMPDC DOMBDC1 DOMBDC2</command></para>

	<para>These are the primary and backup domain controllers Samba 
	will attempt to contact in order to authenticate users. Samba will 
	try to contact each of these servers in order, so you may want to 
	rearrange this list in order to spread out the authentication load 
	among domain controllers.</para>

	<para>Alternatively, if you want smbd to automatically determine 
	the list of Domain controllers to use for authentication, you may 
	set this line to be :</para>

	<para><command>password server = *</command></para>

	<para>This method, which was introduced in Samba 2.0.6, 
	allows Samba to use exactly the same mechanism that NT does. This 
	method either broadcasts or uses a WINS database in order to
	find domain controllers to authenticate against.</para>

	<para>Finally, restart your Samba daemons and get ready for 
	clients to begin using domain security!</para>
</sect1>

<sect1>
<title>Samba and Windows 2000 Domains</title>

<para>
Many people have asked regarding the state of Samba's ability to participate in
a Windows 2000 Domain.  Samba 2.2 is able to act as a member server of a Windows
2000 domain operating in mixed or native mode.
</para>

<para>
There is much confusion between the circumstances that require a "mixed" mode
Win2k DC and a when this host can be switched to "native" mode.  A "mixed" mode
Win2k domain controller is only needed if Windows NT BDCs must exist in the same
domain.  By default, a Win2k DC in "native" mode will still support
NetBIOS and NTLMv1 for authentication of legacy clients such as Windows 9x and 
NT 4.0.  Samba has the same requirements as a Windows NT 4.0 member server.
</para>

<para>
The steps for adding a Samba 2.2 host to a Win2k domain are the same as those
for adding a Samba server to a Windows NT 4.0 domain. The only exception is that 
the "Server Manager" from NT 4 has been replaced by the "Active Directory Users and 
Computers" MMC (Microsoft Management Console) plugin.
</para>

</sect1>


<sect1>
	<title>Why is this better than security = server?</title>

	<para>Currently, domain security in Samba doesn't free you from 
	having to create local Unix users to represent the users attaching 
	to your server. This means that if domain user <constant>DOM\fred
	</constant> attaches to your domain security Samba server, there needs 
	to be a local Unix user fred to represent that user in the Unix 
	filesystem. This is very similar to the older Samba security mode 
	<ulink url="smb.conf.5.html#SECURITYEQUALSSERVER">security = server</ulink>, 
	where Samba would pass through the authentication request to a Windows 
	NT server in the same way as a Windows 95 or Windows 98 server would.
	</para>
	
	<para>Please refer to the <ulink url="winbind.html">Winbind 
	paper</ulink> for information on a system to automatically
	assign UNIX uids and gids to Windows NT Domain users and groups.
	This code is available in development branches only at the moment,
	but will be moved to release branches soon.</para>

	<para>The advantage to domain-level security is that the 
	authentication in domain-level security is passed down the authenticated 
	RPC channel in exactly the same way that an NT server would do it. This 
	means Samba servers now participate in domain trust relationships in 
	exactly the same way NT servers do (i.e., you can add Samba servers into 
	a resource domain and have the authentication passed on from a resource
	domain PDC to an account domain PDC.</para>

	<para>In addition, with <command>security = server</command> every Samba 
	daemon on a server has to keep a connection open to the 
	authenticating server for as long as that daemon lasts. This can drain 
	the connection resources on a Microsoft NT server and cause it to run 
	out of available connections. With <command>security = domain</command>, 
	however, the Samba daemons connect to the PDC/BDC only for as long 
	as is necessary to authenticate the user, and then drop the connection, 
	thus conserving PDC connection resources.</para>

	<para>And finally, acting in the same manner as an NT server 
	authenticating to a PDC means that as part of the authentication 
	reply, the Samba server gets the user identification information such 
	as the user SID, the list of NT groups the user belongs to, etc. All 
	this information will allow Samba to be extended in the future into 
	a mode the developers currently call appliance mode. In this mode, 
	no local Unix users will be necessary, and Samba will generate Unix 
	uids and gids from the information passed back from the PDC when a 
	user is authenticated, making a Samba server truly plug and play 
	in an NT domain environment. Watch for this code soon.</para>

	<para><emphasis>NOTE:</emphasis> Much of the text of this document 
	was first published in the Web magazine <ulink url="http://www.linuxworld.com"> 	
	LinuxWorld</ulink> as the article <ulink
	url="http://www.linuxworld.com/linuxworld/lw-1998-10/lw-10-samba.html">Doing 
	the NIS/NT Samba</ulink>.</para>

</sect1>

</chapter>
