path: root/docs/Samba-Guide/Chap04-SecureOfficeServer.xml

<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE book PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc">
<chapter id="secure">
  <title>Secure Office Networking</title>

	<para>
	Congratulations, your Samba networking skills are developing nicely. You started out
	with three simple networks in Chapter 2, and then in Chapter 3 you designed and built a
	network that provides a high degree of flexibility, integrity, and dependability. It
	was enough for the basic needs each was designed to fulfill. In this chapter you
	address a more complex set of needs. The solution you explore is designed 
	to introduce you to basic features that are specific to Samba-3.
	</para>

	<para>
	You should note that a working and secure solution could be implemented using Samba-2.2.x. 
	In the exercises presented here, you are gradually using more Samba-3 specific features
	so caution is advised for anyone who tries to use Samba-2.2.x with the guidance here given. 
	To avoid confusion, this book is all about Samba-3. Let's get the exercises in this 
	chapter under way.
	</para>

<sect1>
	<title>Introduction</title>

	<para>
	You have made Mr. Meany a very happy man. Recently he paid you a fat bonus for work 
	well done. It is one year since the last network upgrade. You have been quite busy. 
	Two months ago Mr. Meany gave approval to hire Christine Roberson who has taken over 
	general network management. Soon she will provide primary user support. You have demonstrated
	you can delegate responsibility, and plan and execute
	to that plan. Above all, you have shown Mr. Meany that you are a responsible person.
	Today is a big day. Mr. Meany called you to his office at 9 a.m. for news you never 
	expected. You are Mr. Bob Jordan and will take charge of business operations. Mr. Meany 
	is retiring and has entrusted the business to your capable hands. 
	</para>

	<para>
	Mr. Meany may be retiring from this company, but not from work. He is taking the opportunity to develop
	Abmas Inc. into a larger and more substantial company. He says that it took him many
	years to wake up to the fact that there is no future in just running a business. He
	now realizes there is great personal reward and satisfaction in creation of career
	opportunities for people in the local community. He wants to do more for others as he is
	doing for you, Bob Jordan. Today he spent a lot of time talking about the grand plan.
	He has plans for growth that you will deal with in the chapters ahead.
	</para>

	<para>
	Over the past year, the growth projections were exceeded. The network has grown to
	meet the needs of 130 users. Along with growth, the demand for improved services
	and better functionality has also developed. You are about to make an interim
	improvement and then hand over all Help desk and network maintenance to Christine.
	Christine has professional certifications in Microsoft Windows as well as in Linux;
	she is a hard worker and quite likable. Christine does not want to manage the department
	(although she manages well). She gains job satisfaction when left to sort things out.
	Occasionally she wants to work with you on a challenging problem. When you told her
	about your move, she almost resigned, although she was reassured that a new manager would
	be hired to run Information Technology and she would be responsible only for operations.
	</para>

	<sect2>
		<title>Assignment Tasks</title>

		<para>
		You promised the staff Internet services including web browsing, electronic mail, virus
		protection, and a company Web site.  Christine is keen to help turn the vision into 
		reality. Let's see how close you can get to the promises made.
		</para>

		<para>
		The network you are about to deliver will service 130 users today. Within 12 months,
		Abmas will aquire another company. Mr. Meany claims that within two years there will be
		well over 500 users on the network. You have bought into the big picture, so prepare 
		for growth.
		</para>

		<para>
		You have purchased a new server, will implement a new network infrastructure, and 
		reward all staff with a new computer. Notebook computers will not be replaced at this time.
		</para>

		<para>
		You have decided to not recycle old network components. The only items that will be
		carried forward are notebook computers. You offered staff new notebooks, but not 
		one person wanted the disruption for what was perceived as a marginal update. 
		You have made the decision to give everyone a new desktop computer, even to those 
		who have a notebook computer.
		</para>

		<para>
		You have procured a DSL Internet connection that provides 1.5 Megabit/sec (bidirectional)
		and a 10 MBit/sec ethernet port. You have registered the domain
		<constant>abmas.us</constant>, and the Internet Service Provider (ISP) is supplying
		secondary DNS. Information furnished by your ISP is shown in <link linkend="chap4netid"/>.
		</para>

		<para>
		It is of paramount priority that under no circumstances will Samba offer
		service access from an Internet connection. You are paying an ISP to
		give, as part of their value-added services, full firewall protection for your
		connection to the outside world. The only services allowed in from
		the Internet side are the following destination ports: <constant>http/https (ports 
		80 and 443), email (port 25), DNS (port 53)</constant>. All Internet traffic
		will be allowed out after network address translation (NAT). No internal IP addresses
		are permitted through the NAT filter as complete privacy of internal network
		operations must be assured.
		</para>

		<table id="chap4netid">
			<title>Abmas.US ISP Information</title>
			<tgroup cols="2">
				<colspec align="left"/>
				<colspec align="center"/>
				<thead>
					<row>
						<entry>Parameter</entry>
						<entry>Value</entry>
					</row>
				</thead>
				<tbody>
					<row>
						<entry>Server IP Address</entry>
						<entry>123.45.67.66</entry>
					</row>
					<row>
						<entry>DSL Device IP Address</entry>
						<entry>123.45.67.65</entry>
					</row>
					<row>
						<entry>Network Address</entry>
						<entry>123.45.67.64/30</entry>
					</row>
					<row>
						<entry>Gateway Address</entry>
						<entry>123.45.54.65</entry>
					</row>
					<row>
						<entry>Primary DNS Server</entry>
						<entry>123.45.54.65</entry>
					</row>
					<row>
						<entry>Secondary DNS Server</entry>
						<entry>123.45.54.32</entry>
					</row>
					<row>
						<entry>Forwarding DNS Server</entry>
						<entry>123.45.12.23</entry>
					</row>
				</tbody>
			</tgroup>
		</table>

		<image id="ch04net">
			<imagedescription>Abmas Network Topology &smbmdash; 130 Users</imagedescription>
			<imagefile scale="60">chap4-net</imagefile>
		</image>

		<para>
		Christine has recommended that desktop systems should be installed from a single cloned
		master system that has a minimum of locally installed software and loads all software
		off a central application server. The benefit of having the central application server
		is that it allows single point maintenance of all business applications, something
		Christine is keen to pursue. She further recommended installation of anti-virus 
		software on workstations as well as on the Samba server. Christine is paranoid of
		potential virus infection and insists on a comprehensive approach to detective
		as well as corrective action to protect network operations.
		</para>

		<para>
		A significant concern is the problem of managing company growth. Recently, a number 
		of users had to share a PC while waiting for new machines to arrive. This presented 
		some problems with desktop computers and software installation into the new users' 
		desktop profile.
		</para>
		
	</sect2>
</sect1>

<sect1>
	<title>Dissection and Discussion</title>

	<para>
	Many of the conclusions you draw here are obvious. Some requirements are not very clear
	or may simply be your means of drawing the most out of Samba-3. Much can be done more simply
	than you will demonstrate here, but keep in mind that the network must scale to at least 500
	users. This means that some functionality will be over-designed for the current 130 user
	environment.
	</para>

	<sect2>
		<title>Technical Issues</title>

		<para>
		In this exercise we are using a 24-bit subnet mask for the two local networks. This,
		of course, limits our network to a maximum of 253 usable IP addresses. The network
		address range chosen is one of the ranges assigned by RFC1918 for private networks.
		When the number of users on the network begins to approach the limit of usable
		addresses, it would be a good idea to switch to a network address specified in RFC1918
		in the 172.16.0.0/16 range. This is done in the following chapters.
		</para>

		<para>
		<indexterm><primary>tdbsam</primary></indexterm>
		<indexterm><primary>smbpasswd</primary></indexterm>
		The high growth rates projected are a good reason to use the <constant>tdbsam</constant>
		passdb backend. The use of <constant>smbpasswd</constant> for the backend may result in
		performance problems. The <constant>tdbsam</constant> passdb backend offers features that
		are not available with the older flat ASCII-based <constant>smbpasswd</constant> database.
		</para>

		<para>
		<indexterm><primary>risk</primary></indexterm>
		The proposed network design uses a single server to act as an Internet services host for
		electronic mail, Web serving, remote administrative access vis SSH, as well as for 
		Samba-based file and print services. This design is often chosen by sites that feel 	
		they cannot afford or justify the cost or overhead of having separate servers. It must 
		be realized that if security of this type of server should ever be violated (compromised), 
		the whole network and all data is at risk. Many sites continue to choose this type 
		of solution; therefore, this chapter provides detailed coverage of key implementation 
		aspects.
		</para>

		<para>
		Samba will be configured to specifically not operate on the ethernet interface that is
		directly connected to the Internet.
		</para>

		<para>
		<indexterm><primary>iptables</primary></indexterm>
		<indexterm><primary>NAT</primary></indexterm>
		<indexterm><primary>Network Address Translation</primary><see>NAT</see></indexterm>
	  <indexterm>
	    <primary>firewall</primary>
	  </indexterm>
		You know that your ISP is providing full firewall services, but you cannot rely on that.
		Always assume that human error will occur, so be prepared by using Linux firewall facilities
		based on <command>iptables</command> to effect Network Address Translation (NAT). Block all
		incoming traffic except to permitted well-known ports. You must also allow incoming packets
		to established outgoing connections. You will permit all internal outgoing requests.
		</para>

		<para>
		The configuration of Web serving, Web proxy services, electronic mail, and the details of
		generic anti-virus handling are beyond the scope of this book and therefore are not
		covered, except insofar as this affects Samba-3.
		</para>

	<para><indexterm>
	    <primary>login</primary>
	  </indexterm>
		Notebook computers are configured to use a network login when in the office and a
		local account to login while away from the office. Users store all work done in
		transit (away from the office) by using a local share for work files. Standard procedures
		will dictate that on completion of the work that necessitates mobile file access, all
		work files are moved back to secure storage on the office server. Staff is instructed
		to not carry on any company notebook computer any files that are not absolutely required.
		This is a preventative measure to protect client information as well as business private
		records.
		</para>

	<para><indexterm>
	    <primary>application server</primary>
	  </indexterm>
		All applications are served from the central server from a share called <constant>apps</constant>.
		Microsoft Office XP Professional and OpenOffice 1.1.0 will be installed using a network 
		(or administrative) installation. Accounting and financial management software can also
		be run only from the central application server. Notebook users are provided with
		locally installed applications on a need-to-have basis only.
		</para>

		<para>
		<indexterm><primary>roaming profiles</primary></indexterm>
		The introduction of roaming profiles support means that users can move between
		desktop computer systems without constraint while retaining full access to their data.
		The desktop travels with them as they move.
		</para>

		<para>
		<indexterm><primary>DNS</primary></indexterm>
		The DNS server implementation must now address both internal needs as well as external
		needs. You forward DNS lookups to your ISP provided server as well as the 
		<constant>abmas.us</constant> external secondary DNS server.
		</para>

		<para>
		<indexterm><primary>dynamic DNS</primary></indexterm>
	  <indexterm><primary>DDNS</primary><see>dynamic
	      DNS</see></indexterm><indexterm>
	    <primary>DHCP server</primary>
	  </indexterm>
		Compared with the DHCP server configuration in <link linkend="dhcp01"/>, the configuration used
		in this example has to deal with the presence of an Internet connection. The scope set for it
		ensures that no DHCP services will be offered on the external connection. All printers are
		configured as DHCP clients, so that the DHCP server assigns the printer a fixed IP
		address by way of the ethernet interface (MAC) address. One additional feature of this DHCP
		server configuration file is the inclusion of parameters to allow dynamic DNS (DDNS) operation.
		</para>

		<para>
		This is the first implementation that depends on a correctly functioning DNS server.
		Comprehensive steps are included to provide for a fully functioning DNS server that also
		is enabled for dynamic DNS operation. This means that DHCP clients can be auto-registered
		with the DNS server.
		</para>

		<para>
		You are taking the opportunity to manually set the netbios name of the Samba server to
		a name other than what will be automatically resolved. You are doing this to ensure that
		the machine has the same NetBIOS name on both network segments.
		</para>

		<para>
		As in the previous network configuration, printing in this network configuration uses
		direct raw printing (i.e., no smart printing and no print driver auto-download to Windows
		clients). Printer drivers are installed on the Windows client manually. This is not
		a problem given that Christine is to install and configure one single workstation and
		then clone that configuration, using Norton Ghost, to all workstations. Each machine is
		identical, so this should pose no problem.
		</para>

		<sect3>
		<title>Hardware Requirements</title>

	  <para><indexterm>
	      <primary>memory requirements</primary>
	    </indexterm>
		This server runs a considerable number of services. From similarly configured Linux
		installations the approximate calculated memory requirements will be as that shown in
		<link linkend="ch4memoryest"/>.

<example id="ch4memoryest">
<title>Estimation of Memory Requirements</title>
<screen>
Application  Memory per User    130 Users      500 Users
   Name        (MBytes)       Total MBytes   Total MBytes
-----------  ---------------  ------------   ------------
DHCP              2.5               3              3
DNS              16.0              16             16
Samba (nmbd)     16.0              16             16
Samba (winbind)  16.0              16             16
Samba (smbd)      4.0             520           2000
Apache           10.0 (20 User)   200            200
CUPS              3.5              16             32
Basic OS        256.0             256            256
                              -------------- --------------
    Total:                       1043 MBytes    2539 MBytes
                              -------------- --------------
</screen>
</example>
		You would choose to add a safety margin of at least 50% to these estimates. The minimum 
		system memory recommended for initial startup would be 1 GByte, but to permit the system
		to scale to 500 users, it would make sense to provision the machine with 4 GBytes memory.
		An initial configuration with only 1 GByte memory would lead to early performance complaints
		as the system load builds up. Given the low cost of memory, it would not make sense to
		compromise in this area.
		</para>

	  <para><indexterm>
	      <primary>bandwidth calculations</primary>
	    </indexterm>
		Aggregate Input/Output loads should be considered for sizing network configuration as 
		well as disk subsystems. For network bandwidth calculations, one would typically use an
		estimate of 0.1 MBytes/sec per user.  This would suggest that 100-Base-T (approx. 10 MBytes/sec)
		would deliver below acceptable capacity for the initial user load. It is, therefore, a good
		idea to begin with 1 Gigabit ethernet cards for the two internal networks, each attached
		to a 1 Gigabit Etherswitch that provides connectivity to an expandable array of 100-Base-T
		switched ports.
		</para>

	  <para><indexterm>
	      <primary>network segments</primary>
	    </indexterm><indexterm>
	      <primary>RAID</primary>
	    </indexterm>
		Considering the choice of 1 Gigabit ethernet interfaces for the two local network segments,
		the aggregate network I/O capacity will be 2100 MBit/sec (about 230 MBytes/sec), an I/O
		demand that would require a fast disk storage I/O capability. Peak disk throughput is 
		limited by the disk sub-system chosen. It would be desirable to provide the maximum 
		I/O bandwidth that can be afforded. If a low-cost solution must be chosen, the use of 
		3Ware IDE RAID Controllers makes a good choice. These controllers can be fitted into a 
		64 bit, 66 MHz PCI-X slot. They appear to the operating system as a high speed SCSI 
		controller that can operate at the peak of the PCI-X bandwidth (approximately 450 MByte/sec).
		Alternative SCSI-based hardware RAID controllers should also be considered. Alternately,
		it would make sense to purchase well-known branded hardware that has appropriate performance
		specifications. As a minimum, one should attempt to provide a disk sub-system that can
		deliver I/O rates of at least 100 MBytes/sec. 
		</para>

		<para>
		Disk storage requirements may be calculated as shown in <link linkend="ch4diskest"/>.

<example id="ch4diskest">
<title>Estimation of Disk Storage Requirements</title>
<screen>
Corporate Data: 100 MBytes/user per year
Email Storage:  500 MBytes/user per year
Applications:   5000 MBytes
Safety Buffer:  At least 50%

Given 500 Users and 2 years:
-----------------------------
        Corporate Data:  2 x 100 x 500 = 100000 MBytes = 100 GBytes
        Email Storage:   2 x 500 x 500 = 500000 MBytes = 500 GBytes
        Applications:                      5000 MBytes =   5 GBytes
                                       ----------------------------
                             Total:                      605 GBytes
             Add 50% buffer                              303 GBytes
                       Recommended Storage:              908 GBytes
</screen>
</example>
	    <indexterm>
	      <primary>storage capacity</primary>
	    </indexterm>
		The preferred storage capacity should be approximately 1 TeraByte. Use of RAID level 5
		with two hot spare drives would require an 8 drive by 200 GByte capacity per drive array.
		</para>

		</sect3>

	</sect2>


	<sect2>
		<title>Political Issues</title>

		<para>
		Your industry is coming under increasing accountability pressures. Increased paranoia
		is necessary so you can demonstrate that you have acted with due diligence. You must
		not trust your Internet connection.
		</para>

		<para>
		Apart from permitting more efficient management of business applications through use of
		an application server, your primary reason for the decision to implement this is that it
		gives you greater control over software licensing.
		</para>

	<para><indexterm>
	    <primary>Outlook Express</primary>
	  </indexterm>
		You are well aware that the current configuration results in some performance issues
		as the size of the desktop profile grows. Given that users use Microsoft Outlook
		Express, you know that the storage implications of the <constant>.PST</constant> file
		is something that needs to be addressed later on.
		</para>

	</sect2>

</sect1>

<sect1>
	<title>Implementation</title>

	<para>
	<link linkend="ch04net"/> demonstrates the overall design of the network that you will implement.
	</para>

	<para>
	The information presented here assumes that you are already familiar with many basic steps.
	As this stands, the details provided already extend well beyond just the necessities of
	Samba configuration. This decision is deliberate to ensure that key determinants
	of a successful installation are not overlooked. This is the last case that documents
	the finite minutiae of DHCP and DNS server configuration. Beyond the information provided
	here, there are many other good reference books on these subjects.
	</para>

	<para>
	The &smb.conf; file has the following noteworthy features:
	</para>

	<itemizedlist>
		<listitem><para>
		The NetBIOS name of the Samba server is set to <constant>DIAMOND</constant>.
		</para></listitem>

		<listitem><para>
		The Domain name is set to <constant>PROMISES</constant>.
		</para></listitem>

	<listitem><para><indexterm>
	      <primary>broadcast messages</primary>
	    </indexterm><indexterm>
	      <primary>interfaces</primary>
	    </indexterm><indexterm>
	      <primary>bind interfaces only</primary>
	    </indexterm>
		Ethernet interface <constant>eth0</constant> is attached to the Internet connection
		and is externally exposed. This interface is explicitly not available for Samba to use.
		Samba listens on this interface for broadcast messages, but does not broadcast any
		information on <constant>eth0</constant>, nor does it accept any connections from it.
		This is achieved by way of the <parameter>interfaces</parameter> parameter and the
		<parameter>bind interfaces only</parameter> entry.
		</para></listitem>

	<listitem><para><indexterm>
	      <primary>passdb backend</primary>
	    </indexterm><indexterm>
	      <primary>tdbsam</primary>
	    </indexterm><indexterm>
	      <primary>binary database</primary>
	    </indexterm>
		The <parameter>passdb backend</parameter> parameter specifies the creation and use
		of the <constant>tdbsam</constant> password backend. This is a binary database that
		has excellent scalability for a large number of user account entries.
		</para></listitem>

	<listitem><para><indexterm>
	      <primary>WINS serving</primary>
	    </indexterm><indexterm>
	      <primary>wins support</primary>
	    </indexterm><indexterm>
	      <primary>name resolve order</primary>
	    </indexterm>
		WINS serving is enabled by the <smbconfoption name="wins support">Yes</smbconfoption>,
		and name resolution is set to use it by means of the <smbconfoption><name>name resolve order</name>
		<value>wins bcast hosts</value></smbconfoption> entry.
		</para></listitem>

	<listitem><para><indexterm>
	      <primary>time server</primary>
	    </indexterm>
		The Samba server is configured for use by Windows clients as a time server.
		</para></listitem>

	<listitem><para><indexterm>
	      <primary>CUPS</primary>
	    </indexterm><indexterm>
	      <primary>printing</primary>
	    </indexterm><indexterm>
	      <primary>printcap name</primary>
	    </indexterm>
		Samba is configured to directly interface with CUPS via the direct internal interface
		that is provided by CUPS libraries. This is achieved with the 
		<smbconfoption name="printing">CUPS</smbconfoption> as well as the
		<smbconfoption name="printcap name">CUPS</smbconfoption> entries.
		</para></listitem>

	<listitem><para><indexterm>
	      <primary>user management</primary>
	    </indexterm><indexterm>
	      <primary>group management</primary>
	    </indexterm><indexterm>
	      <primary>SRVTOOLS.EXE</primary>
	    </indexterm>
		External interface scripts are provided to enable Samba to interface smoothly to
		essential operating system functions for user and group management. This is important
		to enable workstations to join the Domain, and is also important so that you can use
		the Windows NT4 Domain User Manager, as well as the Domain Server Manager. These tools
		are provided as part of the <filename>SRVTOOLS.EXE</filename> toolkit that can be 
		downloaded from the Microsoft FTP <ulink url="ftp://ftp.microsoft.com/Softlib/MSLFILES/SRVTOOLS.EXE">site.</ulink>
		</para></listitem>

	<listitem><para><indexterm>
	      <primary>User Mode</primary>
	    </indexterm>
		The &smb.conf; file specifies that the Samba server will operate in (default) <parameter>
		security = user</parameter> mode<footnote>See <emphasis>TOSHARG</emphasis>, Chapter 3. This is necessary
		so that Samba can act as a Domain Controller (PDC); see <emphasis>TOSHARG</emphasis>, Chapter 4 for 
		additional information.</footnote> (User Mode).
		</para></listitem>

	<listitem><para><indexterm>
	      <primary>logon services</primary>
	    </indexterm><indexterm>
	      <primary>logon script</primary>
	    </indexterm>
		Domain logon services as well as a Domain logon script are specified. The logon script
		will be used to add robustness to the overall network configuration.
		</para></listitem>

	<listitem><para><indexterm>
	      <primary>roaming profiles</primary>
	    </indexterm><indexterm>
	      <primary>logon path</primary>
	    </indexterm><indexterm>
	      <primary>profile share</primary>
	    </indexterm>
		Roaming profiles are enabled through the specification of the parameter, <smbconfoption><name>logon path</name>
		<value>\\%L\profiles\%U</value></smbconfoption>. The value of this parameter translates the
		<constant>%L</constant> to the name by which the Samba server is called by the client (for this
		configuration, it translates to the name <constant>DIAMOND</constant>), and the <constant>%U</constant>
		will translate to the name of the user within the context of the connection made to the profile share.
		It is the administrator's responsibility to ensure there is a directory in the root of the
		profile share for each user. This directory must be owned by the user also. An exception to this
		requirement is when a profile is created for group use.
		</para></listitem>

	<listitem><para><indexterm>
	      <primary>virus</primary>
	    </indexterm><indexterm>
	      <primary>opportunistic locking</primary>
	    </indexterm>
		Precautionary veto is effected for particular Windows file names that have been targeted by 
		virus-related activity. Additionally, Microsoft Office files are vetoed from opportunistic locking
		controls. This should help to prevent lock contention related file access problems.
		</para></listitem>

	<listitem><para><indexterm>
	      <primary>IPC$</primary>
	    </indexterm>
		Explicit controls are effected to restrict access to the <constant>IPC$</constant> share to
		local networks only. The <constant>IPC$</constant> share plays an important role in network
		browsing and in establishment of network connections.
		</para></listitem>

		<listitem><para>
		Every user has a private home directory on the UNIX/Linux host. This is mapped to
		a network drive that is the same for all users.
		</para></listitem>

	</itemizedlist>

	<para>
	The configuration of the server is the most complex so far. The following steps are used:
	</para>

	<orderedlist numeration="arabic">
		<listitem><para>
		Basic System Configuration
		</para></listitem>

		<listitem><para>
		Samba Configuration
		</para></listitem>

		<listitem><para>
		DHCP and DNS Server Configuration
		</para></listitem>

		<listitem><para>
		Printer Configuration
		</para></listitem>

		<listitem><para>
		Process Start-up Configuration
		</para></listitem>

		<listitem><para>
		Validation
		</para></listitem>

		<listitem><para>
		Application Share Configuration
		</para></listitem>

		<listitem><para>
		Windows Client Configuration
		</para></listitem>
	</orderedlist>

	<para>
	The following sections cover each step in logical and defined detail.
	</para>

	<sect2 id="ch4bsc">
	<title>Basic System Configuration</title>

	<para><indexterm>
	    <primary>SUSE Enterprise Linux Server</primary>
	  </indexterm>
	The preparation in this section assumes that your SUSE Enterprise Linux Server 8.0 system has been
	freshly installed. It prepares basic files so that the system is ready for comprehensive
	operation in line with the network diagram shown in <link linkend="ch04net"/>.
	</para>

	<procedure>
	  <step><para><indexterm>
		<primary>hostname</primary>
	      </indexterm>
		Using the UNIX/Linux system tools, name the server <constant>server.abmas.us</constant>.
		Verify that your hostname is correctly set by running:
<screen>
&rootprompt; uname -n
server
</screen>
		An alternate method to verify the hostname is:
<screen>
&rootprompt; hostname -f
server.abmas.us
</screen>
		</para></step>

		<step><para>
	      <indexterm><primary>/etc/hosts</primary></indexterm><indexterm>
		<primary>localhost</primary>
	      </indexterm>
		Edit your <filename>/etc/hosts</filename> file to include the primary names and addresses
		of all network interfaces that are on the host server. This is necessary so that during
		startup the system can resolve all its own names to the IP address prior to
		startup of the DNS server. An example of entries that should be in the 
		<filename>/etc/hosts</filename> file is:
<screen>
127.0.0.1       localhost
192.168.1.1     sleeth1.abmas.biz sleeth1 diamond
192.168.2.1     sleeth2.abmas.biz sleeth2
123.45.67.66    server.abmas.us server
</screen>
		You should check the startup order of your system. If the CUPS print server is started before
		the DNS server (<command>named</command>), you should also include an entry for the printers
		in the <filename>/etc/hosts</filename> file, as follows:
<screen>
192.168.1.20    qmsa.abmas.biz qmsa
192.168.1.30    hplj6a.abmas.biz hplj6a
192.168.2.20    qmsf.abmas.biz qmsf
192.168.2.30    hplj6f.abmas.biz hplj6f
</screen>
	      <indexterm>
		<primary>named</primary>
	      </indexterm><indexterm>
		<primary>cupsd</primary>
	      </indexterm><indexterm>
		<primary>daemon</primary>
	      </indexterm>
		The printer entries are not necessary if <command>named</command> is started prior to
	      startup of <command>cupsd</command>, the CUPS daemon.
		</para></step>

		<step><para>
		<indexterm><primary>/etc/rc.d/boot.local</primary></indexterm>
	      <indexterm><primary>IP forwarding</primary></indexterm><indexterm>
		<primary>/proc/sys/net/ipv4/ip_forward</primary>
	      </indexterm>
		The host server is acting as a router between the two internal network segments as well
		as for all Internet access. This necessitates that IP forwarding must be enabled. This can be
		achieved by adding to the <filename>/etc/rc.d/boot.local</filename> an entry as follows:
<screen>
echo 1 > /proc/sys/net/ipv4/ip_forward
</screen>
		To ensure that your kernel is capable of IP forwarding during configuration, you may 
		wish to execute that command manually also. This setting permits the Linux system to 
		act as a router.<footnote>ED NOTE: You may want to do the echo command last and include 
		"0" in the init scripts since it opens up your network for a short time.</footnote>
		</para></step>

	  <step><para><indexterm>
		<primary>firewall</primary>
	      </indexterm><indexterm>
		<primary>abmas-netfw.sh</primary>
	      </indexterm>
		Installation of a basic firewall and network address translation facility is necessary.
		The following script can be installed in the <filename>/usr/local/sbin</filename>
		directory. It is executed from the <filename>/etc/rc.d/boot.local</filename> startup
		script. In your case, this script is called <filename>abmas-netfw.sh</filename>. The
		script contents are shown in <link linkend="ch4natfw"/>.

<example id="ch4natfw">
<title>NAT Firewall Configuration Script</title>
<screen>
#!/bin/sh
echo -e "\n\nLoading NAT firewall.\n"
IPTABLES=/usr/sbin/iptables
EXTIF="eth0"
INTIFA="eth1"
INTIFB="eth2"

/sbin/depmod -a
/sbin/insmod ip_tables
/sbin/insmod ip_conntrack
/sbin/insmod ip_conntrack_ftp
/sbin/insmod iptable_nat
/sbin/insmod ip_nat_ftp
$IPTABLES -P INPUT DROP
$IPTABLES -F INPUT
$IPTABLES -P OUTPUT ACCEPT
$IPTABLES -F OUTPUT
$IPTABLES -P FORWARD DROP
$IPTABLES -F FORWARD

$IPTABLES -A INPUT -i lo -j ACCEPT
$IPTABLES -A INPUT -i $INTIFA -j ACCEPT
$IPTABLES -A INPUT -i $INTIFB -j ACCEPT
$IPTABLES -A INPUT -i $EXTIF -m state --state ESTABLISHED,RELATED -j ACCEPT
# Enable incoming traffic for: SSH, SMTP, DNS(tcp), HTTP, HTTPS
for i in 22 25 53 80 443
do
        $IPTABLES -A INPUT -i $EXTIF -p tcp --dport $i  -j ACCEPT
done
# Allow DNS(udp)
$IPTABLES -A INPUT -i $EXTIF -p udp -dport 53  -j ACCEPT
echo "Allow all connections OUT and only existing and specified ones IN"
$IPTABLES -A FORWARD -i $EXTIF -o $INTIFA -m state \
                                  --state ESTABLISHED,RELATED -j ACCEPT
$IPTABLES -A FORWARD -i $EXTIF -o $INTIFB -m state \
                                  --state ESTABLISHED,RELATED -j ACCEPT
$IPTABLES -A FORWARD -i $INTIFA -o $EXTIF -j ACCEPT
$IPTABLES -A FORWARD -i $INTIFB -o $EXTIF -j ACCEPT
$IPTABLES -A FORWARD -j LOG
echo "   Enabling SNAT (MASQUERADE) functionality on $EXTIF"
$IPTABLES -t nat -A POSTROUTING -o $EXTIF -j MASQUERADE
echo "1" > /proc/sys/net/ipv4/ip_forward
echo -e "\nNAT firewall done.\n"
</screen>
</example>
		</para></step>

		<step><para>
		Execute the following to make the script executable:
<screen>
&rootprompt; chmod 755 /usr/local/sbin/abmas-natfw.sh
</screen>
		You must now edit <filename>/etc/rc.d/boot.local</filename> to add an entry
		that runs your <command>abmas-natfw.sh</command> script. The following
		entry works for you:
<screen>
#! /bin/sh
#
# Copyright (c) 2002 SUSE Linux AG Nuernberg, Germany. 
# All rights reserved.
#
# Author: Werner Fink, 1996
#         Burchard Steinbild, 1996
#
# /etc/init.d/boot.local
#
# script with local commands to be executed from init on system startup
#
# Here you should add things that should happen directly after booting
# before we're going to the first run level.
#
/usr/local/sbin/abmas-natfw.sh
</screen>
		</para></step>
	</procedure>

	<para><indexterm>
	    <primary>/etc/hosts</primary>
	  </indexterm>
	The server is now ready for Samba configuration. During the validation step, you remove
	the entry for the Samba server <constant>diamond</constant> from the <filename>/etc/hosts</filename>
	file. This is done after you are satisfied that DNS-based name resolution is functioning correctly.
	</para>

	</sect2>

	<sect2>
	<title>Samba Configuration</title>

	<para>
	When you have completed this section, the Samba server is ready for testing and validation;
	however, testing and validation have to wait until DHCP, DNS, and Printing (CUPS) services have 
	been configured.
	</para>

	<procedure>
		<step><para>
		Install the Samba-3 binary RPM from the Samba-Team FTP site. Assuming that the binary
		RPM file is called <filename>samba-3.0.12-1.i386.rpm</filename>, one way to install this
		file is as follows:
<screen>
&rootprompt; rpm -Uvh samba-3.0.12-1.i386.rpm
</screen>
		This operation must be performed while logged in as the <command>root</command> user.
		Successful operation is clearly indicated. If this installation should fail for any reason,
		refer to the operating system manufacturer's documentation for guidance.
		</para></step>

		<step><para>
		Install the &smb.conf; file shown in <link linkend="promisnet"/>, <link linkend="promisnetsvca"/>,
		and <link linkend="promisnetsvcb"/>. Concatenate (join) all three files to make a single &smb.conf;
		file. The final, fully qualified path for this file should be <filename>/etc/samba/smb.conf</filename>.

<smbconfexample id="promisnet">
<title>130 User Network with <emphasis>tdbsam</emphasis> &smbmdash; [globals] Section</title>
<smbconfcomment>Global parameters</smbconfcomment>
<smbconfsection>[global]</smbconfsection>
<smbconfoption name="workgroup">PROMISES</smbconfoption>
<smbconfoption name="netbios name">DIAMOND</smbconfoption>
<smbconfoption name="interfaces">eth1, eth2, lo</smbconfoption>
<smbconfoption name="bind interfaces only">Yes</smbconfoption>
<smbconfoption name="passdb backend">tdbsam</smbconfoption>
<smbconfoption name="pam password change">Yes</smbconfoption>
<smbconfoption name="passwd chat">*New*Password* %n\n *Re-enter*new*password*</smbconfoption>
<member><parameter> %n\n *Password*changed*</parameter></member>
<smbconfoption name="username map">/etc/samba/smbusers</smbconfoption>
<smbconfoption name="unix password sync">Yes</smbconfoption>
<smbconfoption name="log level">1</smbconfoption>
<smbconfoption name="syslog">0</smbconfoption>
<smbconfoption name="log file">/var/log/samba/%m</smbconfoption>
<smbconfoption name="max log size">50</smbconfoption>
<smbconfoption name="smb ports">139 445</smbconfoption>
<smbconfoption name="name resolve order">wins bcast hosts</smbconfoption>
<smbconfoption name="time server">Yes</smbconfoption>
<smbconfoption name="printcap name">CUPS</smbconfoption>
<smbconfoption name="show add printer wizard">No</smbconfoption>
<smbconfoption name="add user script">/usr/sbin/useradd -m '%u'</smbconfoption>
<smbconfoption name="delete user script">/usr/sbin/userdel -r '%u'</smbconfoption>
<smbconfoption name="add group script">/usr/sbin/groupadd '%g'</smbconfoption>
<smbconfoption name="delete group script">/usr/sbin/groupdel '%g'</smbconfoption>
<smbconfoption name="add user to group script">/usr/sbin/usermod -G '%g' '%u'</smbconfoption>
<smbconfoption name="add machine script">/usr/sbin/useradd</smbconfoption>
<member><parameter>-s /bin/false -d /tmp '%u'</parameter></member>
<smbconfoption name="shutdown script">/var/lib/samba/scripts/shutdown.sh</smbconfoption>
<smbconfoption name="abort shutdown script">/sbin/shutdown -c</smbconfoption>
<smbconfoption name="logon script">scripts\logon.bat</smbconfoption>
<smbconfoption name="logon path">\\%L\profiles\%U</smbconfoption>
<smbconfoption name="logon drive">X:</smbconfoption>
<smbconfoption name="logon home">\\%L\%U</smbconfoption>
<smbconfoption name="domain logons">Yes</smbconfoption>
<smbconfoption name="preferred master">Yes</smbconfoption>
<smbconfoption name="wins support">Yes</smbconfoption>
<smbconfoption name="utmp">Yes</smbconfoption>
<smbconfoption name="map acl inherit">Yes</smbconfoption>
<smbconfoption name="printing">cups</smbconfoption>
<smbconfoption name="veto files">/*.eml/*.nws/*.{*}/</smbconfoption>
<smbconfoption name="veto oplock files">/*.doc/*.xls/*.mdb/</smbconfoption>
</smbconfexample>

<smbconfexample id="promisnetsvca">
<title>130 User Network with <emphasis>tdbsam</emphasis> &smbmdash; Services Section Part A</title>
<smbconfsection>[IPC$]</smbconfsection>
<smbconfoption name="path">/tmp</smbconfoption>
<smbconfoption name="hosts allow">192.168.1.0/24, 192.168.2.0/24, 127.0.0.1</smbconfoption>
<smbconfoption name="hosts deny">0.0.0.0/0</smbconfoption>

<smbconfsection>[homes]</smbconfsection>
<smbconfoption name="comment">Home Directories</smbconfoption>
<smbconfoption name="valid users">%S</smbconfoption>
<smbconfoption name="read only">No</smbconfoption>
<smbconfoption name="browseable">No</smbconfoption>

<smbconfsection>[printers]</smbconfsection>
<smbconfoption name="comment">SMB Print Spool</smbconfoption>
<smbconfoption name="path">/var/spool/samba</smbconfoption>
<smbconfoption name="guest ok">Yes</smbconfoption>
<smbconfoption name="printable">Yes</smbconfoption>
<smbconfoption name="use client driver">Yes</smbconfoption>
<smbconfoption name="default devmode">Yes</smbconfoption>
<smbconfoption name="browseable">No</smbconfoption>

<smbconfsection>[netlogon]</smbconfsection>
<smbconfoption name="comment">Network Logon Service</smbconfoption>
<smbconfoption name="path">/var/lib/samba/netlogon</smbconfoption>
<smbconfoption name="guest ok">Yes</smbconfoption>
<smbconfoption name="locking">No</smbconfoption>
</smbconfexample>

<smbconfexample id="promisnetsvcb">
<title>130 User Network with <emphasis>tdbsam</emphasis> &smbmdash; Services Section Part B</title>
<smbconfsection>[profiles]</smbconfsection>
<smbconfoption name="comment">Profile Share</smbconfoption>
<smbconfoption name="path">/var/lib/samba/profiles</smbconfoption>
<smbconfoption name="read only">No</smbconfoption>
<smbconfoption name="profile acls">Yes</smbconfoption>

<smbconfsection>[accounts]</smbconfsection>
<smbconfoption name="comment">Accounting Files</smbconfoption>
<smbconfoption name="path">/data/accounts</smbconfoption>
<smbconfoption name="read only">No</smbconfoption>

<smbconfsection>[service]</smbconfsection>
<smbconfoption name="comment">Financial Services Files</smbconfoption>
<smbconfoption name="path">/data/service</smbconfoption>
<smbconfoption name="read only">No</smbconfoption>

<smbconfsection>[apps]</smbconfsection>
<smbconfoption name="comment">Application Files</smbconfoption>
<smbconfoption name="path">/apps</smbconfoption>
<smbconfoption name="read only">Yes</smbconfoption>
<smbconfoption name="admin users">bjordan</smbconfoption>
</smbconfexample>
		</para></step>

		<step><para>
	      <indexterm><primary>administrator</primary></indexterm><indexterm>
		<primary>smbpasswd</primary>
	      </indexterm>
		Add the <constant>root</constant> user to the password backend as follows:
<screen>
&rootprompt; smbpasswd -a root
New SMB password: XXXXXXXX
Retype new SMB password: XXXXXXXX
&rootprompt;
</screen>
		The <constant>root</constant> account is the UNIX equivalent of the Windows Domain Administrator.
		This account is essential in the regular maintenance of your Samba server. It must never be
		deleted. If for any reason the account is deleted, you may not be able to recreate this account
		without considerable trouble.
		</para></step>

		<step><para>
		<indexterm><primary>username map</primary></indexterm>
                Create the username map file to permit the <constant>root</constant> account to be called
                <constant>Administrator</constant> from the Windows network environment. To do this, create
                the file <filename>/etc/samba/smbusers</filename> with the following contents:
<screen>
####
# User mapping file
####
# File Format
# -----------
# Unix_ID = Windows_ID
#
# Examples:
# root = Administrator
# janes = "Jane Smith"
# jimbo = Jim Bones
#
# Note: If the name contains a space it must be double quoted.
#       In the example above the name 'jimbo' will be mapped to Windows
#       user names 'Jim' and 'Bones' because the space was not quoted.
#######################################################################
root = Administrator
####
# End of File
####
</screen>
		</para></step>

		<step><para>
	      <indexterm><primary>initGrps.sh</primary></indexterm><indexterm>
		<primary>net</primary>
		<secondary>groupmap</secondary>
		<tertiary>add</tertiary>
	      </indexterm><indexterm>
		<primary>net</primary>
		<secondary>groupmap</secondary>
		<tertiary>modify</tertiary>
	      </indexterm><indexterm>
		<primary>net</primary>
		<secondary>groupmap</secondary>
		<tertiary>list</tertiary>
	      </indexterm>
                Create and map Windows Domain Groups to UNIX groups. A sample script is provided in
                <link linkend="initGrps"/>. Create a file containing this script. We called ours
                <filename>/etc/samba/initGrps.sh</filename>. Set this file so it can be executed,
                and then execute the script. Sample output should be as follows:

<example id="ch4initGrps">
<title>Script to Map Windows NT Groups to UNIX Groups</title>
<indexterm><primary>initGrps.sh</primary></indexterm>
<screen>
#!/bin/bash
#
# initGrps.sh
#

# Create UNIX groups
groupadd acctsdep
groupadd finsrvcs

# Map Windows Domain Groups to UNIX groups
net groupmap modify ntgroup="Domain Admins"  unixgroup=root
net groupmap modify ntgroup="Domain Users"   unixgroup=users
net groupmap modify ntgroup="Domain Guests"  unixgroup=nobody

# Add Functional Domain Groups
net groupmap add ntgroup="Accounts Dept"  unixgroup=acctsdep type=d
net groupmap add ntgroup="Financial Services" unixgroup=finsrvcs type=d

# Map Windows NT machine local groups to local UNIX groups
# Mapping of local groups is not necessary and not functional
# for this installation.
</screen>
</example>

<screen>
&rootprompt; chmod 755 initGrps.sh
&rootprompt; /etc/samba # ./initGrps.sh
Updated mapping entry for Domain Admins
Updated mapping entry for Domain Users
Updated mapping entry for Domain Guests
No rid or sid specified, choosing algorithmic mapping
Successfully added group Accounts Dept to the mapping db
No rid or sid specified, choosing algorithmic mapping
Successfully added group Domain Guests to the mapping db

&rootprompt; /etc/samba # net groupmap list | sort
Account Operators (S-1-5-32-548) -> -1
Accounts Dept (S-1-5-21-179504-2437109-488451-2003) -> acctsdep
Administrators (S-1-5-32-544) -> -1
Backup Operators (S-1-5-32-551) -> -1
Domain Admins (S-1-5-21-179504-2437109-488451-512) -> root
Domain Guests (S-1-5-21-179504-2437109-488451-514) -> nobody
Domain Users (S-1-5-21-179504-2437109-488451-513) -> users
Financial Services (S-1-5-21-179504-2437109-488451-2005) -> finsrvcs
Guests (S-1-5-32-546) -> -1
Power Users (S-1-5-32-547) -> -1
Print Operators (S-1-5-32-550) -> -1
Replicators (S-1-5-32-552) -> -1
System Operators (S-1-5-32-549) -> -1
Users (S-1-5-32-545) -> -1
</screen>
		</para></step>

	  <step><para>
	  <indexterm><primary>useradd</primary></indexterm>
          <indexterm><primary>adduser</primary></indexterm>
	  <indexterm><primary>passwd</primary></indexterm>
	  <indexterm><primary>smbpasswd</primary></indexterm>
          <indexterm><primary>/etc/passwd</primary></indexterm>
          <indexterm><primary>password</primary><secondary>backend</secondary></indexterm>
          <indexterm><primary>user</primary><secondary>management</secondary></indexterm>
		There is one preparatory step without which you will not have a working Samba 
		network environment. You must add an account for each network user. 
                For each user who needs to be given a Windows Domain account, make an entry in the
                <filename>/etc/passwd</filename> file, as well as in the Samba password backend.
                Use the system tool of your choice to create the UNIX system account, and use the Samba
                <command>smbpasswd</command> to create a Domain user account.
                There are a number of tools for user management under UNIX. Commonly known ones include:
                <command>useradd, adduser</command>. In addition to these, there are a plethora of custom
                tools. You also want to create a home directory for each user.
		You can do this by executing the following steps for each user:
<screen>
&rootprompt; useradd -m <parameter>username</parameter>
&rootprompt; passwd <parameter>username</parameter>
Changing password for <parameter>username</parameter>.
New password: XXXXXXXX
Re-enter new password: XXXXXXXX
Password changed
&rootprompt; smbpasswd -a <parameter>username</parameter>
New SMB password: XXXXXXXX
Retype new SMB password: XXXXXXXX
Added user <parameter>username</parameter>.
</screen>
		You do of course use a valid user login ID in place of <parameter>username</parameter>.
		</para></step>

	  <step><para><indexterm>
		<primary>file system</primary>
		<secondary>access control</secondary>
	      </indexterm><indexterm>
		<primary>file system</primary>
		<secondary>permissions</secondary>
	      </indexterm><indexterm>
		<primary>group membership</primary>
	      </indexterm>
                Using the preferred tool for your UNIX system, add each user to the UNIX groups created
                previously as necessary. File system access control will be based on UNIX group membership.
                </para></step>

                <step><para>
                Create the directory mount point for the disk sub-system that can be mounted to provide
                data storage for company files. In this case the mount point indicated in the &smb.conf;
                file is <filename>/data</filename>. Format the file system as required, and mount the formatted
                file system partition using appropriate system tools.
                </para></step>

                <step><para>
		<indexterm><primary>file system</primary><secondary>permissions</secondary></indexterm>
                Create the top-level file storage directories for data and applications as follows:
<screen>
&rootprompt; mkdir -p /data/{accounts,finsvcs}
&rootprompt; mkdir -p /apps
&rootprompt; chown -R root.root /data
&rootprompt; chown -R root.root /apps
&rootprompt; chown -R bjordan.accounts /data/accounts
&rootprompt; chown -R bjordan.finsvcs /data/finsvcs
&rootprompt; chmod -R ug+rwxs,o-rwx /data
&rootprompt; chmod -R ug+rwx,o+rx-w /apps
</screen>
                Each department is responsible for creating its own directory structure within the departmental
                share. The directory root of the <command>accounts</command> share is <filename>/data/accounts</filename>.
                The directory root of the <command>finsvcs</command> share is <filename>/data/finsvcs</filename>.
		The <filename>/apps</filename> directory is the root of the <constant>apps</constant> share
		that provides the application server infrastructure.
		</para></step>

		<step><para>
		The &smb.conf; file specifies an infrastructure to support roaming profiles and network
		logon services. You can now create the file system infrastructure to provide the
		locations on disk that these services require. Adequate planning is essential
		since desktop profiles can grow to be quite large. For planning purposes, a minimum of
		200 Megabytes of storage should be allowed per user for profile storage. The following
		commands create the directory infrastructure needed:
<screen>
&rootprompt; mkdir -p /var/spool/samba 
&rootprompt; mkdir -p /var/lib/samba/{netlogon/scripts,profiles}
&rootprompt; chown -R root.root /var/spool/samba
&rootprompt; chown -R root.root /var/lib/samba
&rootprompt; chmod a+rwxt /var/spool/samba
</screen>
		For each user account that is created on the system, the following commands should be
		executed:
<screen>
&rootprompt; mkdir /var/lib/samba/profiles/'username'
&rootprompt; chown 'username'.users /var/lib/samba/profiles/'username'
&rootprompt; chmod ug+wrx,o+rx,-w /var/lib/samba/profiles/'username'
</screen>
		</para></step>

	  <step><para><indexterm>
		<primary>logon scrip</primary>
	      </indexterm><indexterm>
		<primary>unix2dos</primary>
	      </indexterm><indexterm>
		<primary>dos2unix</primary>
	      </indexterm>
		Create a logon script. It is important that each line is correctly terminated with
		a carriage return and line-feed combination (i.e., DOS encoding). The following procedure
		works if the right tools (<constant>unix2dos</constant> and <constant>dos2unix</constant>) are installed.
		First, create a file called <filename>/var/lib/samba/netlogon/scripts/logon.bat.unix</filename>
		with the following contents:
<screen>
net time \\diamond /set /yes
net use h: /home
net use p: \\diamond\apps
</screen>
		Convert the UNIX file to a DOS file using the <command>unix2dos</command> as shown here:
<screen>
&rootprompt; unix2dos &lt; /var/lib/samba/netlogon/scripts/logon.bat.unix \
	&gt; /var/lib/samba/netlogon/scripts/logon.bat
</screen>
		</para></step>
	</procedure>

	</sect2>

	<sect2 id="ch4dhcpdns">
	<title>Configuration of DHCP and DNS Servers</title>

	<para>
	DHCP services are a basic component of the entire network client installation. DNS operation is
	foundational to Internet access as well as to trouble-free operation of local networking. When
	you have completed this section, the server should be ready for solid duty operation.
	</para>

	<procedure>
		<step><para>
		<indexterm><primary>/etc/dhcpd.conf</primary></indexterm>
		Create a file called <filename>/etc/dhcpd.conf</filename> with the contents as
		shown in <link linkend="prom-dhcp"/>.

<example id="prom-dhcp">
<title>DHCP Server Configuration File &smbmdash; <filename>/etc/dhcpd.conf</filename></title>
<screen>
# Abmas Accounting Inc. - Chapter 4
default-lease-time 86400;
max-lease-time 172800;
default-lease-time 86400;
option ntp-servers 192.168.1.1;
option domain-name "abmas.biz";
option domain-name-servers 192.168.1.1, 192.168.2.1;
option netbios-name-servers 192.168.1.1, 192.168.2.1;
option netbios-node-type 8;       ### Node type = Hybrid ###
ddns-updates on;                  ### Dynamic DNS enabled ###
ddns-update-style ad-hoc;

subnet 192.168.1.0 netmask 255.255.255.0 {
        range dynamic-bootp 192.168.1.128 192.168.1.254;
        option subnet-mask 255.255.255.0;
        option routers 192.168.1.1;
        allow unknown-clients;
        host qmsa {
                hardware ethernet 08:00:46:7a:35:e4;
                fixed-address 192.168.1.20;
                }
        host hplj6a {
                hardware ethernet 00:03:47:cb:81:e0;
                fixed-address 192.168.1.30;
                }
        }
subnet 192.168.2.0 netmask 255.255.255.0 {
        range dynamic-bootp 192.168.2.128 192.168.2.254;
        option subnet-mask 255.255.255.0;
        option routers 192.168.2.1;
        allow unknown-clients;
        host qmsf {
                hardware ethernet 01:04:31:db:e1:c0;
                fixed-address 192.168.1.20;
        	}
        host hplj6f {
                hardware ethernet 00:03:47:cf:83:e2;
                fixed-address 192.168.2.30;
                }
	}
subnet 127.0.0.0 netmask 255.0.0.0 {
        }
subnet 123.45.67.64 netmask 255.255.255.252 {
        }
</screen>
</example>
		</para></step>

		<step><para>
		<indexterm><primary>/etc/named.conf</primary></indexterm>
		Create a file called <filename>/etc/named.conf</filename> that has the combined contents
		of the <link linkend="ch4namedcfg"/>, <link linkend="ch4namedvarfwd"/>, and
		<link linkend="ch4namedvarrev"/> files that are concatenated (merged) in this
		specific order.
		</para></step>

		<step><para>
		Create the files shown in their directories as follows:

			<table if="namedrscfiles">
				<title>DNS (named) Resource Files</title>
				<tgroup cols="2">
					<colspec align="left"/>
					<colspec align="left"/>
					<thead>
						<row>
							<entry>Reference</entry>
							<entry>File Location</entry>
						</row>
					</thead>
					<tbody>
						<row>
							<entry><link linkend="loopback"/></entry>
							<entry>/var/lib/named/localhost.zone</entry>
						</row>
						<row>
							<entry><link linkend="dnsloopy"/></entry>
							<entry>/var/lib/named/127.0.0.zone</entry>
						</row>
						<row>
							<entry><link linkend="roothint"/></entry>
							<entry>/var/lib/named/root.hint</entry>
						</row>
						<row>
							<entry><link linkend="abmasbiz"/></entry>
							<entry>/var/lib/named/master/abmas.biz.hosts</entry>
						</row>
						<row>
							<entry><link linkend="abmasus"/></entry>
							<entry>/var/lib/named/abmas.us.hosts</entry>
						</row>
						<row>
							<entry><link linkend="eth1zone"/></entry>
							<entry>/var/lib/named/192.168.1.0.rev</entry>
						</row>
						<row>
							<entry><link linkend="eth2zone"/></entry>
							<entry>/var/lib/named/192.168.2.0.rev</entry>
						</row>
					</tbody>
				</tgroup>
			</table>

<example id="ch4namedcfg">
<title>DNS Master Configuration File &smbmdash; <filename>/etc/named.conf</filename> Master Section</title>
<indexterm><primary>/etc/named.conf</primary></indexterm>
<screen>
###
# Abmas Biz DNS Control File
###
# Date: November 15, 2003
###
options {
	directory "/var/lib/named";
	forwarders {
		123.45.12.23;
		};
	forward first;
	listen-on {
		mynet;
		};
	auth-nxdomain yes;
	multiple-cnames yes;
	notify no;
};

zone "." in {
	type hint;
	file "root.hint";
};

zone "localhost" in {
	type master;
	file "localhost.zone";
};

zone "0.0.127.in-addr.arpa" in {
	type master;
	file "127.0.0.zone";
};

acl mynet {
	192.168.1.0/24;
	192.168.2.0/24;
	127.0.0.1;
};

acl seconddns {
	123.45.54.32;
}

</screen>
</example>

<example id="ch4namedvarfwd">
<title>DNS Master Configuration File &smbmdash; <filename>/etc/named.conf</filename> Forward Lookup Definition Section</title>
<screen>
zone "abmas.biz" {
	type master;
	file "/var/lib/named/master/abmas.biz.hosts";
	allow-query {
		mynet;
	};
	allow-transfer {
		mynet;
	};
	allow-update {
		mynet;
	};
};

zone "abmas.us" {
	type master;
	file "/var/lib/named/master/abmas.us.hosts";
	allow-query {
		all;
	};
	allow-transfer {
		seconddns;
	};
};
</screen>
</example>

<example id="ch4namedvarrev">
<title>DNS Master Configuration File &smbmdash; <filename>/etc/named.conf</filename> Reverse Lookup Definition Section</title>
<screen>
zone "1.168.192.in-addr.arpa" {
	type master;
	file "/var/lib/named/master/192.168.1.0.rev";
	allow-query {
		mynet;
	};
	allow-transfer {
		mynet;
	};
	allow-update {
		mynet;
	};
};

zone "2.168.192.in-addr.arpa" {
	type master;
	file "/var/lib/named/master/192.168.2.0.rev";
	allow-query {
		mynet;
	};
	allow-transfer {
		mynet;
	};
	allow-update {
		mynet;
	};
};
</screen>
</example>

<example id="eth1zone">
<title>DNS 192.168.1 Reverse Zone File</title>
<screen>
$ORIGIN .
$TTL 38400	; 10 hours 40 minutes
1.168.192.in-addr.arpa	IN SOA	sleeth.abmas.biz. root.abmas.biz. (
				2003021825 ; serial
				10800      ; refresh (3 hours)
				3600       ; retry (1 hour)
				604800     ; expire (1 week)
				38400      ; minimum (10 hours 40 minutes)
				)
			NS	sleeth1.abmas.biz.
$ORIGIN 1.168.192.in-addr.arpa.
1			PTR	sleeth1.abmas.biz.
20			PTR	qmsa.abmas.biz.
30			PTR	hplj6a.abmas.biz.
</screen>
</example>

<example id="eth2zone">
<title>DNS 192.168.2 Reverse Zone File</title>
<screen>
$ORIGIN .
$TTL 38400	; 10 hours 40 minutes
2.168.192.in-addr.arpa	IN SOA	sleeth.abmas.biz. root.abmas.biz. (
				2003021825 ; serial
				10800      ; refresh (3 hours)
				3600       ; retry (1 hour)
				604800     ; expire (1 week)
				38400      ; minimum (10 hours 40 minutes)
				)
			NS	sleeth2.abmas.biz.
$ORIGIN 2.168.192.in-addr.arpa.
1			PTR	sleeth2.abmas.biz.
20			PTR	qmsf.abmas.biz.
30			PTR	hplj6f.abmas.biz.
</screen>
</example>

<example id="abmasbiz">
<title>DNS Abmas.biz Forward Zone File</title>
<screen>
$ORIGIN .
$TTL 38400      ; 10 hours 40 minutes
abmas.biz       IN SOA  sleeth1.abmas.biz. root.abmas.biz. (
                                2003021833 ; serial
                                10800      ; refresh (3 hours)
                                3600       ; retry (1 hour)
                                604800     ; expire (1 week)
                                38400      ; minimum (10 hours 40 minutes)
                                )
                        NS      dns.abmas.biz.
                        MX      10 mail.abmas.biz.
$ORIGIN abmas.biz.
sleeth1                 A       192.168.1.1
sleeth2                 A       192.168.2.1
qmsa                    A       192.168.1.20
hplj6a                  A       192.168.1.30
qmsf                    A       192.168.2.20
hplj6f                  A       192.168.2.30
dns                     CNAME   sleeth1
diamond                 CNAME   sleeth1
mail                    CNAME   sleeth1
</screen>
</example>

<example id="abmasus">
<title>DNS Abmas.us Forward Zone File</title>
<screen>
$ORIGIN .
$TTL 38400      ; 10 hours 40 minutes
abmas.us        IN SOA  server.abmas.us. root.abmas.us. (
                                2003021833 ; serial
                                10800      ; refresh (3 hours)
                                3600       ; retry (1 hour)
                                604800     ; expire (1 week)
                                38400      ; minimum (10 hours 40 minutes)
                                )
                        NS      dns.abmas.us.
                        NS      dns2.abmas.us.
                        MX      10 mail.abmas.us.
$ORIGIN abmas.us.
server                  A       123.45.67.66
dns2                    A       123.45.54.32
gw                      A       123.45.67.65
www                     CNAME   server
mail                    CNAME   server
dns                     CNAME   server
</screen>
</example>

		</para></step>

		<step><para>
	      <indexterm><primary>/etc/resolv.conf</primary></indexterm><indexterm>
		<primary>name resolution</primary>
	      </indexterm>
		All DNS name resolution should be handled locally. To ensure that the server is configured
		correctly to handle this, edit <filename>/etc/resolv.conf</filename> to have the following
		content:
<screen>
search abmas.us abmas.biz
nameserver 127.0.0.1
nameserver 123.45.54.23
</screen>
	      <indexterm>
		<primary>DNS server</primary>
	      </indexterm>
		This instructs the name resolver function (when configured correctly) to ask the DNS server
		that is running locally to resolve names to addresses. In the event that the local name server
		is not available, ask the name server provided by the ISP. The latter, of course, does not resolve
		purely local names to IP addresses.
		</para></step>

		<step><para>
		<indexterm><primary>/etc/nsswitch.conf</primary></indexterm>
		The final step is to edit the <filename>/etc/nsswitch.conf</filename> file.
		This file controls the operation of the various resolver libraries that are part of the Linux
		Glibc libraries. Edit this file so that it contains the following entries:
<screen>
hosts:      files dns wins
</screen>
		</para></step>
	</procedure>

	<para>
	The basic DHCP and DNS services are now ready for validation testing. Before you can proceed,
	there are a few more steps along the road. First, configure the print spooling and print
	processing system.  Then you can configure the server so that all services
	start automatically on reboot. You must also manually start all services prior to validation testing.
	</para>

	</sect2>

	<sect2 id="ch4ptrcfg">
	<title>Printer Configuration</title>

	<para>
	</para>

	<procedure>
		<step><para>
		Configure each printer to be a DHCP client carefully following the manufacturer's guidelines.
		</para></step>

                <step><para>
                Follow the instructions in the printer manufacturers' manuals to permit printing to port 9100.
		Use any other port the manufacturer specifies for direct mode, raw printing and adjust the
		port as necessary in the following example commands.
                This allows the CUPS spooler to print using raw mode protocols.
                <indexterm><primary>CUPS</primary></indexterm>
                <indexterm><primary>raw printing</primary></indexterm>
                </para></step>

                <step><para>
	      <indexterm><primary>CUPS</primary><secondary>queue</secondary></indexterm><indexterm>
		<primary>lpadmin</primary>
	      </indexterm>
                Configure the CUPS Print Queues as follows:
<screen>
&rootprompt; lpadmin -p qmsa -v socket://qmsa.abmas.biz:9100 -E
&rootprompt; lpadmin -p hplj6a -v socket://hplj6a.abmas.biz:9100 -E
&rootprompt; lpadmin -p qmsf -v socket://qmsf.abmas.biz:9100 -E
&rootprompt; lpadmin -p hplj6f -v socket://hplj6f.abmas.biz:9100 -E
</screen>
                <indexterm><primary>print filter</primary></indexterm>
                This has created the necessary print queues with no assigned print filter.
                </para></step>

	  <step><para><indexterm>
		<primary>enable</primary>
	      </indexterm>
		Print queues may not be enabled at creation. Use <command>lpc stat</command> to check
		the status of the print queues and if necessary make certain that the queues you have 
		just created are enabled by executing the following:
<screen>
&rootprompt; /usr/bin/enable qmsa
&rootprompt; /usr/bin/enable hplj6a
&rootprompt; /usr/bin/enable qmsf
&rootprompt; /usr/bin/enable hplj6f
</screen>
		</para></step>

	  <step><para><indexterm>
		<primary>accept</primary>
	      </indexterm>
		Even though your print queues may be enabled, it is still possible that they
		are not accepting print jobs. A print queue services incoming printing
		requests only when configured to do so. Ensure that your print queues are
		set to accept incoming jobs by executing the following commands:
<screen>
&rootprompt; /usr/bin/accept qmsa
&rootprompt; /usr/bin/accept hplj6a
&rootprompt; /usr/bin/accept qmsf
&rootprompt; /usr/bin/accept hplj6f
</screen>
		</para></step>

                <step><para>
                <indexterm><primary>mime type</primary></indexterm>
                <indexterm><primary>/etc/mime.convs</primary></indexterm>
                <indexterm><primary>application/octet-stream</primary></indexterm>
                Edit the file <filename>/etc/cups/mime.convs</filename> to uncomment the line:
<screen>
application/octet-stream     application/vnd.cups-raw      0     -
</screen>
                </para></step>

                <step><para>
                <indexterm><primary>/etc/mime.types</primary></indexterm>
                Edit the file <filename>/etc/cups/mime.types</filename> to uncomment the line:
<screen>
application/octet-stream
</screen>
                </para></step>

		<step><para>
		Printing drivers are installed on each network client workstation.
		</para></step>
	</procedure>

	<para>
	The UNIX system print queues have been configured and are ready for validation testing.
	</para>

	</sect2>

	<sect2 id="procstart">
	<title>Process Startup Configuration</title>

	<para>
	<indexterm><primary>chkconfig</primary></indexterm>
	There are two essential steps to process startup configuration. First, the process
	must be configured so that it automatically restarts each time the server
	is rebooted. This step involves use of the <command>chkconfig</command> tool that
	creates the appropriate symbolic links from the master daemon control file that is
	located in the <filename>/etc/rc.d</filename> directory, to the <filename>/etc/rc'x'.d</filename>
	directories. Links are created so that when the system run-level is changed, the
	necessary start or kill script is run.
	</para>

	<para>
	  <indexterm><primary>/etc/xinetd.d</primary></indexterm><indexterm>
	    <primary>inetd</primary>
	  </indexterm><indexterm>
	    <primary>xinetd</primary>
	  </indexterm><indexterm>
	    <primary>chkconfig</primary>
	  </indexterm><indexterm>
	    <primary>super daemon</primary>
	  </indexterm>
	In the event that a service is not run as a daemon, but via the inter-networking
	super daemon (<command>inetd</command> or <command>xinetd</command>), then the <command>chkconfig</command>
	tool makes the necessary entries in the <filename>/etc/xinetd.d</filename> directory
	and sends a hang-up (HUP) signal to the the super daemon, thus forcing it to
	re-read its control files.
	</para>

	<para>
	Last, each service must be started to permit system validation to proceed.
	</para>

	<procedure>
                <step><para>
                Use the standard system tool to configure each service to restart
                automatically at every system reboot. For example:
                <indexterm><primary>chkconfig</primary></indexterm>
<screen>
&rootprompt; chkconfig dhpc on
&rootprompt; chkconfig named on
&rootprompt; chkconfig cups on
&rootprompt; chkconfig smb on
</screen>
		</para></step>

		<step><para>
                <indexterm><primary>starting dhcpd</primary></indexterm>
                <indexterm><primary>starting samba</primary></indexterm>
                <indexterm><primary>starting CUPS</primary></indexterm>
		Now start each service to permit the system to be validated.
		Execute each of the following in the sequence shown:

<screen>
&rootprompt; /etc/rc.d/init.d/dhcp restart
&rootprompt; /etc/rc.d/init.d/named restart
&rootprompt; /etc/rc.d/init.d/cups restart
&rootprompt; /etc/rc.d/init.d/smb restart
</screen>
                </para></step>
	</procedure>

	</sect2>

	<sect2 id="ch4valid">
	<title>Validation</title>

	<para><indexterm>
	    <primary>validation</primary>
	  </indexterm>
	Complex networking problems are most often caused by simple things that are poorly or incorrectly
	configured. The validation process adopted here should be followed carefully; it is the result of the
	experience gained from years of making and correcting the most common mistakes. Shortcuts often lead to basic errors. You should
	refrain from taking shortcuts, from making basic assumptions, and from not exercising due process
	and diligence in network validation. By thoroughly testing and validating every step in the process
	of network installation and configuration, you can save yourself from sleepless nights and restless
	days. A well debugged network is a foundation for happy network users and network administrators. 
	Later in this book you learn how to make users happier. For now, it is enough to learn to 
	validate. Let's get on with it.
	</para>

		<procedure>

			<step><para>
			<indexterm><primary>/etc/nsswitch.conf</primary></indexterm>
			One of the most important facets of Samba configuration is to ensure that
			name resolution functions correctly. You can test name resolution
			with a few simple tests. The most basic name resolution is provided from the
			<filename>/etc/hosts</filename> file. To test its operation, make a
			temporary edit to the <filename>/etc/nsswitch.conf</filename> file. Using
			your favorite editor, change the entry for <constant>hosts</constant> to read:
<screen>
hosts:     files
</screen>
			When you have saved this file, execute the following command:
<screen>
&rootprompt; ping diamond
PING sleeth1.abmas.biz (192.168.1.1) 56(84) bytes of data.
64 bytes from sleeth1 (192.168.1.1): icmp_seq=1 ttl=64 time=0.131 ms
64 bytes from sleeth1 (192.168.1.1): icmp_seq=2 ttl=64 time=0.179 ms
64 bytes from sleeth1 (192.168.1.1): icmp_seq=3 ttl=64 time=0.192 ms
64 bytes from sleeth1 (192.168.1.1): icmp_seq=4 ttl=64 time=0.191 ms

--- sleeth1.abmas.biz ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3016ms
rtt min/avg/max/mdev = 0.131/0.173/0.192/0.026 ms
</screen>
			This proves that name resolution via the <filename>/etc/hosts</filename> file
			is working.
			</para></step>

			<step><para>
			<indexterm><primary>/etc/nsswitch.conf</primary></indexterm>
			So far, your installation is going particularly well. In this step we validate
			DNS server and name resolution operation. Using your favorite UNIX system editor,
			change the <filename>/etc/nsswitch.conf</filename> file so that the
			<constant>hosts</constant> entry reads:
<screen>
hosts:        dns
</screen>
			</para></step>

			<step><para>
			<indexterm><primary>named</primary></indexterm>
			Before you test DNS operation, it is a good idea to verify that the DNS server
			is running by executing the following:
<screen>
&rootprompt; ps ax | grep named
  437 ?        S      0:00 /sbin/syslogd -a /var/lib/named/dev/log
  524 ?        S      0:00 /usr/sbin/named -t /var/lib/named -u named
  525 ?        S      0:00 /usr/sbin/named -t /var/lib/named -u named
  526 ?        S      0:00 /usr/sbin/named -t /var/lib/named -u named
  529 ?        S      0:00 /usr/sbin/named -t /var/lib/named -u named
  540 ?        S      0:00 /usr/sbin/named -t /var/lib/named -u named
 2552 pts/2    S      0:00 grep named
</screen>
			This means that we are ready to check DNS operation. Do so by executing:
			<indexterm><primary>ping</primary></indexterm>
<screen>
&rootprompt; ping diamond
PING sleeth1.abmas.biz (192.168.1.1) 56(84) bytes of data.
64 bytes from sleeth1 (192.168.1.1): icmp_seq=1 ttl=64 time=0.156 ms
64 bytes from sleeth1 (192.168.1.1): icmp_seq=2 ttl=64 time=0.183 ms

--- sleeth1.abmas.biz ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 999ms
rtt min/avg/max/mdev = 0.156/0.169/0.183/0.018 ms
</screen>
			You should take a few more steps to validate DNS server operation, as follows:
<screen>
&rootprompt; host -f diamond.abmas.biz
sleeth1.abmas.biz has address 192.168.1.1
</screen>
			<indexterm><primary>/etc/hosts</primary></indexterm>
			You may now remove the entry called <constant>diamond</constant> from the
			<filename>/etc/hosts</filename> file. It does not hurt to leave it there,
			but its removal reduces the number of administrative steps for this name.
			</para></step>

			<step><para>
			<indexterm><primary>/etc/nsswitch.conf</primary></indexterm>
			WINS is a great way to resolve NetBIOS names to their IP address. You can test
			the operation of WINS by starting <command>nmbd</command> (manually, or by way
			of the Samba startup method shown in <link linkend="procstart"/>). You must edit
			the <filename>/etc/nsswitch.conf</filename> file so that the <constant>hosts</constant>
			entry is as follows:
<screen>
hosts:        wins
</screen>
			The next step is to make certain that Samba is running using <command>ps ax|grep mbd</command>, and then execute the following:
<screen>
&rootprompt; ping diamond
PING diamond (192.168.1.1) 56(84) bytes of data.
64 bytes from 192.168.1.1: icmp_seq=1 ttl=64 time=0.094 ms
64 bytes from 192.168.1.1: icmp_seq=2 ttl=64 time=0.479 ms
</screen>
			<indexterm><primary>ping</primary></indexterm>
			Now that you can relax with the knowledge that all three major forms of name
			resolution to IP address resolution are working, edit the <filename>/etc/nsswitch.conf</filename>
			again. This time you add all three forms of name resolution to this file.
			Your edited entry for <constant>hosts</constant> should now look like this:
<screen>
hosts:       file dns wins
</screen>
			The system is looking good. Let's move on.
			</para></step>

			<step><para>
			It would give peace of mind to know that the DHCP server is running
			and available for service. You can validate DHCP services by running:

<screen>
&rootprompt; ps ax | grep dhcp
 2618 ?        S      0:00 /usr/sbin/dhcpd ...
 8180 pts/2    S      0:00 grep dhcp
</screen>
			This shows that the server is running. The proof of whether or not it is working
			comes when you try to add the first DHCP client to the network.
			</para></step>

			<step><para>
			<indexterm><primary>testparm</primary></indexterm>
			This is a good point at which to start validating Samba operation. You are 
			content that name resolution is working for basic TCP/IP needs. Let's move on.
			If your &smb.conf; file has bogus options or parameters, this may cause Samba
			to refuse to start. The first step should always be to validate the contents
			of this file by running:
<screen>
&rootprompt; testparm -s
Load smb config files from /etc/samba/smb.conf
Processing section "[IPC$]"
Processing section "[homes]"
Processing section "[printers]"
Processing section "[netlogon]"
Processing section "[profiles]"
Processing section "[accounts]"
Processing section "[service]"
Processing section "[apps]"
Loaded services file OK.
# Global parameters
[global]
        workgroup = PROMISES
        netbios name = DIAMOND
        interfaces = eth1, eth2, lo
        bind interfaces only = Yes
        passdb backend = tdbsam
        pam password change = Yes
        passwd chat = *New*Password* %n\n \
		*Re-enter*new*password* %n\n *Password*changed*
        username map = /etc/samba/smbusers
        unix password sync = Yes
        log level = 1
        syslog = 0
        log file = /var/log/samba/%m
        max log size = 50
        smb ports = 139 445
        name resolve order = wins bcast hosts
        time server = Yes
        printcap name = CUPS
        show add printer wizard = No
        add user script = /usr/sbin/useradd -m %u
        delete user script = /usr/sbin/userdel -r %u
        add group script = /usr/sbin/groupadd %g
        delete group script = /usr/sbin/groupdel %g
        add user to group script = /usr/sbin/usermod -G %g %u
        add machine script = /usr/sbin/useradd \
				-s /bin/false -d /var/lib/nobody %u
        shutdown script = /var/lib/samba/scripts/shutdown.sh
        abort shutdown script = /sbin/shutdown -c
        logon script = scripts\logon.bat
        logon path = \\%L\profiles\%U
        logon drive = X:
        logon home = \\%L\%U
        domain logons = Yes
        preferred master = Yes
        wins support = Yes
        utmp = Yes
        winbind use default domain = Yes
        map acl inherit = Yes
        printing = cups
        veto files = /*.eml/*.nws/riched20.dll/*.{*}/
        veto oplock files = /*.doc/*.xls/*.mdb/

[IPC$]
        path = /tmp
        hosts allow = 192.168.1.0/24, 192.168.2.0/24, 127.0.0.1
        hosts deny = 0.0.0.0/0
...
### Remainder cut to save space ###
</screen>
			Clear away all errors before proceeding.
			</para></step>

			<step><para>
			<indexterm><primary>check samba daemons</primary></indexterm>
			<indexterm><primary>smbd</primary></indexterm>
			<indexterm><primary>nmbd</primary></indexterm>
			<indexterm><primary>winbindd</primary></indexterm>
			Check that the Samba server is running:
<screen>
&rootprompt; ps ax | grep mbd
14244 ?        S      0:00 /usr/sbin/nmbd -D
14245 ?        S      0:00 /usr/sbin/nmbd -D
14290 ?        S      0:00 /usr/sbin/smbd -D

$rootprompt; ps ax | grep winbind
14293 ?        S     0:00 /usr/sbin/winbindd -B
14295 ?        S     0:00 /usr/sbin/winbindd -B
</screen>
			The <command>winbindd</command> daemon is running in split mode (normal), so there are also
			two instances<footnote>For more information regarding winbindd, see <emphasis>TOSHARG</emphasis>, 
			Chapter 22, Section 22.3. The single instance of <command>smbd</command> is normal. One additional
			<command>smbd</command> slave process is spawned for each SMB/CIFS client 
			connection.</footnote> of it.
			</para></step>
	
			<step><para>
			<indexterm><primary>anonymous
		  connection</primary></indexterm>
	      <indexterm>
		<primary>smbclient</primary>
	      </indexterm>
			Check that an anonymous connection can be made to the Samba server:
<screen>
&rootprompt; smbclient -L localhost -U%

        Sharename      Type      Comment
        ---------      ----      -------
        IPC$           IPC       IPC Service (Samba 3.0.12)
        netlogon       Disk      Network Logon Service
        profiles       Disk      Profile Share
        accounts       Disk      Accounting Files
        service        Disk      Financial Services Files
        apps           Disk      Application Files
        ADMIN$         IPC       IPC Service (Samba 3.0.12)
        hplj6a         Printer   hplj6a
        hplj6f         Printer   hplj6f
        qmsa           Printer   qmsa
        qmsf           Printer   qmsf

        Server               Comment
        ---------            -------
        DIAMOND              Samba CVS 3.0.12

        Workgroup            Master
        ---------            -------
        PROMISES             DIAMOND
</screen>
			This demonstrates that an anonymous listing of shares can be obtained. This is the equivalent
			of browsing the server from a Windows client to obtain a list of shares on the server.
			The <constant>-U%</constant> argument means "send a <constant>NULL</constant> username and
			a <constant>NULL</constant> password."
			</para></step>

			<step><para>
			<indexterm><primary>dhcp client validation</primary></indexterm>
			<indexterm><primary>printer validation</primary></indexterm>
			<indexterm><primary>arp</primary></indexterm>
			Verify that each printer has the IP address assigned in the DHCP server configuration file.
			The easiest way to do this is to ping the printer name. Immediately after the ping response
			has been received, execute <command>arp -a</command> to find the MAC address of the printer
			that has responded. Now you can compare the IP address and the MAC address of the printer
			with the configuration information in the <filename>/etc/dhcpd.conf</filename> file. They
			should, of course, match. For example:
<screen>
&rootprompt; ping hplj6
PING hplj6a (192.168.1.30) 56(84) bytes of data.
64 bytes from hplj6a (192.168.1.30): icmp_seq=1 ttl=64 time=0.113 ms

&rootprompt; arp -a
hplj6a (192.168.1.30) at 00:03:47:CB:81:E0 [ether] on eth0
</screen>
	      <indexterm>
		<primary>/etc/dhcpd.conf</primary>
	      </indexterm>
			The MAC address <constant>00:03:47:CB:81:E0</constant> matches that specified for the
			IP address from which the printer has responded and with the entry for it in the
			<filename>/etc/dhcpd.conf</filename> file. Repeat this for each printer configured.
			</para></step>
	
			<step><para>
			<indexterm><primary>authenticated connection</primary></indexterm>
			Make an authenticated connection to the server using the <command>smbclient</command> tool:
<screen>
&rootprompt; smbclient //diamond/accounts -U gholmes
Password: XXXXXXX
smb: \> dir
  .                          D        0  Thu Nov 27 15:07:09 2003
  ..                         D        0  Sat Nov 15 17:40:50 2003
  zakadmin.exe                   161424  Thu Nov 27 15:06:52 2003
  zak.exe                       6066384  Thu Nov 27 15:06:52 2003
  dhcpd.conf                       1256  Thu Nov 27 15:06:52 2003
  smb.conf                         2131  Thu Nov 27 15:06:52 2003
  initGrps.sh                A     1089  Thu Nov 27 15:06:52 2003
  POLICY.EXE                      86542  Thu Nov 27 15:06:52 2003

                55974 blocks of size 65536. 33968 blocks available
smb: \> q
</screen>
			</para></step>

			<step><para>
			<indexterm><primary>nmap</primary></indexterm>
			Your new server is connected to an Internet accessible connection. Before you start
			your firewall, you should run a port scanner against your system. You should repeat that
			after the firewall has been started. This helps you understand what extent the
			server may be vulnerable to external attack. One way you can do this is by using an
			external service provided such as the <ulink url="http://www.dslreports.com/scan">DSL Reports</ulink> 
			tools. Alternately, if you can gain root-level access to a remote
			UNIX/Linux system that has the <command>nmap</command> tool, you can run this as follows:
<screen>
&rootprompt; nmap -v -sT server.abmas.us

Starting nmap V. 3.00 ( www.insecure.org/nmap/ )
Host server.abmas.us (123.45.67.66) appears to be up ... good.
Initiating Connect() Scan against server.abmas.us (123.45.67.66)
Adding open port 6000/tcp
Adding open port 873/tcp
Adding open port 445/tcp
Adding open port 10000/tcp
Adding open port 901/tcp
Adding open port 631/tcp
Adding open port 25/tcp
Adding open port 111/tcp
Adding open port 32770/tcp
Adding open port 3128/tcp
Adding open port 53/tcp
Adding open port 80/tcp
Adding open port 443/tcp
Adding open port 139/tcp
Adding open port 22/tcp
The Connect() Scan took 0 seconds to scan 1601 ports.
Interesting ports on server.abmas.us (123.45.67.66):
(The 1587 ports scanned but not shown below are in state: closed)
Port       State       Service
22/tcp     open        ssh
25/tcp     open        smtp
53/tcp     open        domain
80/tcp     open        http
111/tcp    open        sunrpc
139/tcp    open        netbios-ssn
443/tcp    open        https
445/tcp    open        microsoft-ds
631/tcp    open        ipp
873/tcp    open        rsync
901/tcp    open        samba-swat
3128/tcp   open        squid-http
6000/tcp   open        X11
10000/tcp  open        snet-sensor-mgmt
32770/tcp  open        sometimes-rpc3

Nmap run completed -- 1 IP address (1 host up) scanned in 1 second
</screen>
			The above scan was run before the external interface was locked down with the NAT-firewall
			script you created above. The following results are obtained after the firewall rules
			have been put into place:
<screen>
&rootprompt; nmap -v -sT server.abmas.us

Starting nmap V. 3.00 ( www.insecure.org/nmap/ )
Host server.abmas.us (123.45.67.66) appears to be up ... good.
Initiating Connect() Scan against server.abmas.us (123.45.67.66)
Adding open port 53/tcp
Adding open port 22/tcp
The Connect() Scan took 168 seconds to scan 1601 ports.
Interesting ports on server.abmas.us (123.45.67.66):
(The 1593 ports scanned but not shown below are in state: filtered)
Port       State       Service
22/tcp     open        ssh
25/tcp     closed      smtp
53/tcp     open        domain
80/tcp     closed      http
443/tcp    closed      https

Nmap run completed -- 1 IP address (1 host up) scanned in 168 seconds
</screen>
			</para></step>
	
		</procedure>

	</sect2>

	<sect2 id="ch4appscfg">
	<title>Application Share Configuration</title>

	<para><indexterm>
	    <primary>application server</primary>
	  </indexterm><indexterm>
	    <primary>administrative installation</primary>
	  </indexterm>
	The use of an application server is a key mechanism by which desktop administration overheads
	can be reduced. Check the application manual for your software to identify how best to
	create an administrative installation.
	</para>

	<para>
	Some Windows software will only run locally on the desktop computer. Such software
	is typically not suited for administrative installation. Administratively installed software
	permits one or more of the following installation choices:
	</para>

	<itemizedlist>
		<listitem><para>
		Install software fully onto a workstation, storing data files on the same workstation.
		</para></listitem>

		<listitem><para>
		Install software fully onto a workstation with central network data file storage.
		</para></listitem>

		<listitem><para>
		Install software to run off a central application server with data files stored
		on the local workstation. This is often called a minimum installation, or a
		network client installation.
		</para></listitem>

		<listitem><para>
		Install software to run off a central application server with data files stored
		on a central network share. This type of installation often prevents storage
		of work files on the local workstation.
		</para></listitem>
	</itemizedlist>

	<para><indexterm>
	    <primary></primary>
	  </indexterm>
	A common application deployed in this environment is an office suite.
	Enterprise editions of Microsoft Office XP Professional can be administratively installed
	by launching the installation from a command shell. The command that achieves this is:
	<command>setup /a</command>. It results in a set of prompts through which various
	installation choices can be made. Refer to the Microsoft Office Resource SDK and Resource
	Kit for more information regarding this mode of installation of MS Office XP Professional.
	The full administrative installation of MS Office XP Professional requires approximately
	650 MB of disk space.
	</para>

	<para>
	When the MS Office XP Professional product has been installed to the administrative network
	share, the product can be installed onto a workstation by executing the normal setup program.
	The installation process now provides a choice to either perform a minimum installation
	or a full local installation. A full local installation takes over 100 MB of disk space.
	A network workstation (minimum) installation requires typically 10-15 MB of
	local disk space. In the later case, when the applications are used, they load over the network.
	</para>

	<para><indexterm>
	    <primary>Service Packs</primary>
	  </indexterm><indexterm>
	    <primary>Microsoft Office</primary>
	  </indexterm>
	Microsoft Office Service Packs can be unpacked to update an administrative share. This makes
	it possible to update MS Office XP Professional for all users from a single installation
	of the service pack and generally circumvents the need to run updates on each network
	Windows client.
	</para>	

	<para>
	The default location for MS Office XP Professional data files can be set through registry
	editing or by way of configuration options inside each Office XP Professional application.
	</para>

	<para><indexterm>
	    <primary>OpenOffice</primary>
	  </indexterm>
	OpenOffice.Org OpenOffice Version 1.1.0 is capable of being installed locally. It can also
	be installed to run off a network share. The latter is a most desirable solution for office-bound 
	network users and for administrative staff alike. It permits quick and easy updates
	to be rolled out to all users with a minimum of disruption and with maximum flexibility.
	</para>

	<para>
	The process for installation of administrative shared OpenOffice involves download of the
	distribution ZIP file, followed by extraction of the ZIP file into a temporary disk area.
	When fully extracted using the un-zipping tool of your choosing, change into the Windows
	installation files directory then execute <command>setup -net</command>. You are
	prompted on screen for the target installation location. This is the administrative
	share point. The full administrative OpenOffice share takes approximately 150 MB of disk
	space.
	</para>

		<sect3>
		<title>Comments Regarding Software Terms of Use</title>
			<para>
			Many single-user products can be installed into an administrative share, but
			personal versions of products such as Microsoft Office XP Professional do not permit this. 
			Many people do not like terms of use typical with commercial products, so a few comments
			regarding software licensing seem important and thus are included below.
			</para>

			<para>
			Please do not use an administrative installation of proprietary and commercially licensed 
			software products to violate the copyright holders' property. All software is licensed,
			particularly software that is licensed for use free of charge. All software is the property
			of the copyright holder, unless the author and/or copyright holder has explicitly disavowed
			ownership and has placed the software into the public domain.
			</para>

			<para>
			Software that is under the GNU General Public License, like proprietary software, is 
			licensed in a way that restricts use. For example, if you modify GPL software and then
			distribute the binary version of your modifications, you must offer to provide the source
			code as well. This is a form of restriction that is designed to maintain the momentum
			of the diffusion of technology and to protect against the withholding of innovations.
			</para>

			<para>
			Commercial and proprietary software generally restrict use to those who have paid the
			license fees and who comply with the licensee's terms of use. Software that is released
			under the GNU General Public License is restricted to particular terms and conditions
			also. Whatever the licensing terms may be, if you do not approve of the terms of use,
			please do not use the software.
			</para>

	  <para><indexterm>
	      <primary>GPL</primary>
	    </indexterm>
			Samba is provided under the terms of the GNU GPL Version 2, a copy of which is provided
			with the source code.
			</para>
		</sect3>

	</sect2>

	<sect2 id="ch4wincfg">
	<title>Windows Client Configuration</title>

	<para>
	Christine needs to roll out 130 new desktop systems. There is no doubt that she also needs
	to reinstall many of the notebook computers that will be recycled for use with the new network 
	configuration. The smartest way to handle the challenge of the roll-out program is to build
	a staged system for each type of target machine, and then use an image replication tool such as Norton
	Ghost (enterprise edition) to replicate the staged machine to its target desktops. The same can
	be done with notebook computers as long as they are identical or sufficiently similar.
	</para>

	<procedure>
		<step><para>
		Install MS Windows XP Professional. During installation, configure the client to use DHCP for 
		TCP/IP protocol configuration.
		<indexterm><primary>WINS</primary></indexterm>
		<indexterm><primary>DHCP</primary></indexterm>
		DHCP configures all Windows clients to use the WINS Server address that has been defined
		for the local subnet.
		</para></step>

		<step><para>
		Join the Windows Domain <constant>PROMISES</constant>. Use the Domain Administrator
		user name <constant>root</constant> and the SMB password you assigned to this account.
		A detailed step-by-step procedure for joining a Windows 200x/XP Professional client to
		a Windows Domain is given in <link linkend="domjoin"/>. 
		Reboot the machine as prompted and then logon using the Domain Administrator account
		(<constant>root</constant>.
		</para></step>

		<step><para>
		Verify <constant>DIAMOND</constant> is visible in <guimenu>My Network Places</guimenu>, 
		that it is possible to connect to it and see the shares <guimenuitem>accounts</guimenuitem>,
		<guimenuitem>apps</guimenuitem>, and <guimenuitem>finsvcs</guimenuitem>,
		and that it is possible to open each share to reveal its contents.
		</para></step>

		<step><para>
		Create a drive mapping to the <constant>apps</constant> share on the server <constant>DIAMOND</constant>.
		</para></step>

		<step><para>
		Perform an administrative installation of each application to be used. Select the options
		that you wish to use. Of course, you can choose to run applications over the network, correct?
		</para></step>

		<step><para>
		Now install all applications to be installed locally. Typical tools includes: Adobe Acrobat,
		NTP-based time synchronization software, drivers for specific local devices such as finger-print
		scanners, and the like. Probably the most significant application for local installation
		is anti-virus software.
		</para></step>

		<step><para>
		Now install all four printers onto the staging system. The printers you install
		include the Accounting department HP LaserJet 6 and Minolta QMS Magicolor printers. You will
		also configure identical printers that are located in the financial services department.
		Install printers on each machine using the following steps:

			<procedure>
				<step><para>
				Click <menuchoice>
					<guimenu>Start</guimenu>
					<guimenuitem>Settings</guimenuitem>
					<guimenuitem>Printers</guimenuitem>
					<guiicon>Add Printer</guiicon>
					<guibutton>Next</guibutton>
					</menuchoice>. Do not click <guimenuitem>Network printer</guimenuitem>.
					Ensure that <guimenuitem>Local printer</guimenuitem> is selected.
				</para></step>

				<step><para>
				Click <guibutton>Next</guibutton>. In the panel labeled
				<guimenuitem>Manufacturer:</guimenuitem>, select <constant>HP</constant>.
				In the <guimenuitem>Printers:</guimenuitem> panel, select the printer called
				<constant>HP LaserJet 6</constant>. Click <guibutton>Next</guibutton>.
				</para></step>

				<step><para>
				In the panel labeled <guimenuitem>Available ports:</guimenuitem>, select
				<constant>FILE:</constant>. Accept the default printer name by clicking
				<guibutton>Next</guibutton>. When asked, <quote>Would you like to print a
				test page?,</quote> click <guimenuitem>No</guimenuitem>. Click
				<guibutton>Finish</guibutton>.
				</para></step>

				<step><para>
				You may be prompted for the name of a file to print to. If so, close the
				dialog panel. Right-click <menuchoice>
					<guiicon>HP LaserJet 6</guiicon>
					<guimenuitem>Properties</guimenuitem>
					<guimenusub>Details (Tab)</guimenusub>
					<guimenubutton>Add Port</guimenubutton>
					</menuchoice>.
				</para></step>

				<step><para>
				In the panel labeled <guimenuitem>Network</guimenuitem>, enter the name of
				the print queue on the Samba server as follows: <constant>\\DIAMOND\hplj6a</constant>.
				Click <menuchoice> 
					<guibutton>OK</guibutton>
					<guibutton>OK</guibutton>
					</menuchoice> to complete the installation.
				</para></step>

				<step><para>
				Repeat the printer installation steps above for both HP LaserJet 6 printers
				as well as for both QMS Magicolor laser printers.
				</para></step>
			</procedure>
		</para></step>

	  <step><para><indexterm>
		<primary>defragmentation</primary>
	      </indexterm>
		When you are satisfied that the staging systems are complete, use the appropriate procedure to
		remove the client from the domain. Reboot the system and then log on as the local administrator
		and clean out all temporary files stored on the system. Before shutting down, use the disk
		defragmentation tool so that the file system is in an optimal condition before replication.
		</para></step>

	  <step><para>
		Boot the workstation using the Norton (Symantec) Ghosting diskette (or CD-ROM) and image the
		machine to a network share on the server.
		</para></step>

		<step><para><indexterm>
		<primary>Windows security identifier</primary>
		<see>SID</see>
	      </indexterm><indexterm>
		<primary>SID</primary>
	      </indexterm>
		You may now replicate the image to the target machines using the appropriate Norton Ghost 
		procedure. Make sure to use the procedure that ensures each machine has a unique
		Windows security identifier (SID). When the installation of the disk image has completed, boot the PC. 
		</para></step>

		<step><para>
		Log onto the machine as the local Administrator (the only option), and join the machine to
		the Domain following the procedure set out in <link linkend="domjoin"/>. The system is now 
		ready for the user to logon, providing you have created a network logon account for that 
		user, of course.
		</para></step>

		<step><para>
		Instruct all users to log onto the workstation using their assigned user name and password.
		</para></step>
	</procedure>

	</sect2>

	<sect2>
	<title>Key Points Learned</title>

		<para>
		How do you feel, Bob? You have built a capable network, a truly ambitious project.
		Just as well, you have Christine to help you. Future network updates can be handled by
		your staff. You must be a satisfied manager. Let's review the achievements.
		</para>

		<itemizedlist>
			<listitem><para>
			A simple firewall has been configured to protect the server in the event that
			the ISP firewall service should fail.
			</para></listitem>

			<listitem><para>
			The Samba configuration uses measures to ensure that only local network users
			can connect to SMB/CIFS services.
			</para></listitem>

			<listitem><para>
			Samba uses the new <constant>tdbsam</constant> passdb backend facility.
			Considerable complexity was added to Samba functionality.
			</para></listitem>

			<listitem><para>
			A DHCP server was configured to implement dynamic DNS (DDNS) updates to the DNS
			server.
			</para></listitem>

			<listitem><para>
			The DNS server was configured to permit DDNS only for local network clients. This
			server also provides primary DNS services for the company Internet presence.
			</para></listitem>

			<listitem><para>
			You introduced an application server, as well as the concept of cloning a Windows
			client in order to effect improved standardization of desktops and to reduce
			the costs of network management.
			</para></listitem>
		</itemizedlist>

	</sect2>

</sect1>

<sect1>
	<title>Questions and Answers</title>

	<para>
	</para>

	<qandaset defaultlabel="chap04qa" type="number">
	<qandaentry>
	<question>

		<para>
		What is the maximum number of account entries that the <parameter>tdbsam</parameter> passdb backend can handle?
		</para>

	</question>
	<answer>

		<para>
		The tdb data structure and support system can handle more entries than the number of accounts
		that are possible on most UNIX systems. There is a practical limit that would come into play
		long before a performance boundary would be anticipated. That practical limit is controlled
		by the nature of Windows networking. There are few Windows file and print servers
		that can handle more than a few hundred concurrent client connections. The key limiting factors
		that predicate off-loading of services to additional servers are memory capacity, the number
		of CPUs, network bandwidth, and disk I/O limitations. All of these are readily exhausted by
		just a few hundred concurrent active users. Such bottlenecks can best be removed by segmentation
		of the network (distributing network load across multiple networks).
		</para>
		<para>
		As the network grows, it becomes necessary to provide additional authentication servers (domain 
		controllers).  The tdbsam is limited to a single machine and cannot be reliably replicated. 
		This means that practical limits on network design dictate the point at which a distributed 
		passdb backend is required; at this time, there is no real alternative other than ldapsam (LDAP).
		</para>

		<para>
		The guideline provided in <emphasis>TOSHARG</emphasis>, Chapter 10, Section 10.1.2, is to limit the number of accounts
		in the tdbsam backend to 250. This is the point at which most networks tend to want backup domain
		controllers (BDCs). Samba-3 does not provide a mechanism for replicating tdbsam data so it can be used
		by a BDC. The limitation of 250 users per tdbsam is predicated only on the need for replication
		not on the limits<footnote>Bench tests have shown that tdbsam is a very effective database technology.
		There is surprisingly little performance loss even with over 4000 users.</footnote> of the tdbsam backend itself. 
		</para>

	</answer>
	</qandaentry>

	<qandaentry>
	<question>

		<para>
		Would Samba operate any better if the OS Level is set to a value higher than 35?
		</para>

	</question>
	<answer>

		<para>
		No. MS Windows workstations and servers do not use a value higher than 33. Setting this to a value
		of 35 already assures Samba of precedence over MS Windows products in browser elections. There is
		no gain to be had from setting this higher.
		</para>

	</answer>
	</qandaentry>

	<qandaentry>
	<question>

		<para>
		Why in this example have you provided UNIX group to Windows Group mappings for only Domain Groups?
		</para>

	</question>
	<answer>

		<para>
		At this time, Samba has the capacity to use only Domain Groups mappings. It is possible that at
		a later date Samba may make use of Windows Local Groups, as well as of the Active Directory special
		Groups. Proper operation requires Domain Groups to be mapped to valid UNIX groups.
		</para>

	</answer>
	</qandaentry>

	<qandaentry>
	<question>

		<para>
		Why has a path been specified in the <parameter>IPC$</parameter> share?
		</para>

	</question>
	<answer>

		<para>
		This is done so that in the event that a software bug may permit a client connection to the IPC$ share to
		obtain access to the file system, it does so at a location that presents least risk. Under normal operation
		this type of paranoid step should not be necessary. The use of this parameter should not be necessary. 
		</para>

	</answer>
	</qandaentry>

	<qandaentry>
	<question>

		<para>
		Why does the &smb.conf; file in this exercise include an entry for <smbconfoption name="smb ports"/>?
		</para>

	</question>
	<answer>

		<para>
		The default order by which Samba-3 attempts to communicate with MS Windows clients is via port 445 (the TCP port
		used by Windows clients when NetBIOS-less SMB over TCP/IP is in use). TCP port 139 is the primary port used for NetBIOS
		over TCP/IP. In this configuration Windows network operations are predicated around NetBIOS over TCP/IP. By
		specifying the use of port 139 before port 445, the intent is to reduce unsuccessful service connection attempts.
		The result of this is improved network performance. Where Samba-3 is installed as an Active Directory Domain
		member, the default behavior is highly beneficial and should not be changed.
		</para>

	</answer>
	</qandaentry>

	<qandaentry>
	<question>

		<para>
		What is the difference between a print queue and a printer?
		</para>

	</question>
	<answer>

		<para>
		A printer is a physical device that is connected either directly to the network or to a computer 
		via a serial, parallel, or USB connection so that print jobs can be submitted to it to create a 
		hard copy printout. Network attached printers that use TCP/IP-based printing generally accept a 
		single print data stream and block all secondary attempts to dispatch jobs concurrently to the 
		same device. If many clients were to concurrently print directly via TCP/IP to the same printer, 
		it would result in a huge amount of network traffic through continually failing connection attempts.
		</para>

		<para>
		A print server (like CUPS or LPR/LPD) accepts multiple concurrent input streams or
		print requests. When the data stream has been fully received the input stream is closed,
		the job is then submitted to a sequential print queue where the job is stored until
		the printer is ready to receive the job.
		</para>

	</answer>
	</qandaentry>

	<qandaentry>
	<question>

		<para>
		Can all MS Windows application software be installed onto an application server share?
		</para>

	</question>
	<answer>

		<para>
		Much older Windows software is not compatible with installation to and execution off
		an application server. Enterprise versions of Microsoft Office XP Professional can
		be installed to an application server. Retail consumer versions of Microsoft Office XP
		Professional do not permit installation to an application server share and can be installed
		and used only to/from a local workstation hard disk.
		</para>

	</answer>
	</qandaentry>

	<qandaentry>
	<question>

		<para>
		Why use dynamic DNS (DDNS)?
		</para>

	</question>
	<answer>

		<para>
		When DDNS records are updated directly from the DHCP server, it is possible for
		network clients that are not NetBIOS enabled, and thus cannot use WINS, to locate
		Windows clients via DNS.
		</para>

	</answer>
	</qandaentry>

	<qandaentry>
	<question>

		<para>
		Why would you use WINS as well as DNS-based name resolution?
		</para>

	</question>
	<answer>

		<para>
		WINS is to NetBIOS names as DNS is to fully qualified domain names (FQDN). The FQDN is
		a name like <quote>myhost.mydomain.tld,</quote> where <parameter>tld</parameter>
		means <constant>top level domain</constant>. A FQDN is a long hand but easy to remember
		expression that may be up to 1024 characters in length and that represents an IP address. 
		A NetBIOS name is always 16 characters long. The 16<superscript>th</superscript> character
		is a name type indicator. A specific name type is registered<footnote>
		See <emphasis>TOSHARG</emphasis>, Chapter 9 for more information.</footnote> for each 
		type of service that is provided by the Windows server or client and that may be registered
		where a WINS server is in use.
		</para>

		<para>
		WINS is a mechanism by which a client may locate the IP Address that corresponds to a
		NetBIOS name. The WINS server may be queried to obtain the IP Address for a NetBIOS name 
		that includes a particular registered NetBIOS name type. DNS does not provide a mechanism
		that permits handling of the NetBIOS name type information.
		</para>

		<para>
		DNS provides a mechanism by which TCP/IP clients may locate the IP address of a particular 
		hostname or service name that has been registered in the DNS database for a particular domain. 
		A DNS server has limited scope of control and is said to be authoritative for the zone over
		which it has control.
		</para>

		<para>
		Windows 200x Active Directory requires the registration in the DNS zone for the domain it 
		controls of service locator<footnote>See TOSHARG, Chapter 9, Section 9.3.3</footnote> records 
		that Windows clients and servers will use to locate Kerberos and LDAP services. ADS also 
		requires the registration of special records that are called global catalog (GC) entries 
		and site entries by which domain controllers and other essential ADS servers may be located. 
		</para>

	</answer>
	</qandaentry>

	<qandaentry>
	<question>

		<para>
		What are the major benefits of using an application server?
		</para>

	</question>
	<answer>

		<para>
		The use of an application server can significantly reduce application update maintenance.
		By providing a centralized application share, software updates need be applied to only
		one location for all major applications used. This results in faster update roll-outs and
		significantly better application usage control.
		</para>

	</answer>
	</qandaentry>

	</qandaset>

</sect1>

</chapter>