1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Chapter�1.�Networking Primer</title><link rel="stylesheet" href="samba.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.66.1"><link rel="start" href="index.html" title="Samba-3 by Example"><link rel="up" href="index.html" title="Samba-3 by Example"><link rel="prev" href="preface.html" title="Preface"><link rel="next" href="simple.html" title="Chapter�2.�No Frills Samba Servers"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter�1.�Networking Primer</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="preface.html">Prev</a>�</td><th width="60%" align="center">�</th><td width="20%" align="right">�<a accesskey="n" href="simple.html">Next</a></td></tr></table><hr></div><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="primer"></a>Chapter�1.�Networking Primer</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="sect1"><a href="primer.html#id2526817">Requirements and Notes</a></span></dt><dt><span class="sect1"><a href="primer.html#id2526988">Introduction</a></span></dt><dd><dl><dt><span class="sect2"><a href="primer.html#id2527050">Assignment Tasks</a></span></dt></dl></dd><dt><span class="sect1"><a href="primer.html#id2527169">Exercises</a></span></dt><dd><dl><dt><span class="sect2"><a href="primer.html#id2527295">Single Machine Broadcast Activity</a></span></dt><dt><span class="sect2"><a href="primer.html#secondmachine">Second Machine Startup Broadcast Interaction</a></span></dt><dt><span class="sect2"><a href="primer.html#id2528431">Simple Windows Client Connection Characteristics</a></span></dt><dt><span class="sect2"><a href="primer.html#id2528925">Windows 200x/XP Client Interaction with Samba-3</a></span></dt><dt><span class="sect2"><a href="primer.html#id2529492">Conclusions to Exercises</a></span></dt></dl></dd><dt><span class="sect1"><a href="primer.html#chap01conc">Dissection and Discussion</a></span></dt><dd><dl><dt><span class="sect2"><a href="primer.html#id2529608">Technical Issues</a></span></dt></dl></dd><dt><span class="sect1"><a href="primer.html#chap01qa">Questions and Answers</a></span></dt></dl></div><p> 2 You are about to use the equivalent of a microscope to look at the information 3 that runs through the veins of a Windows network. We do more to observe the information than 4 to interrogate it. When you are done with this chapter, you should have a good understanding 5 of the types of information that flow over the network. Do not worry, this is not 6 a biology lesson. We won't lose you in unnecessary detail. Think to yourself, “<span class="quote"><span class="emphasis"><em>This 7 is easy,</em></span></span>” then tackle each exercise without fear. 8 </p><p> 9 Samba can be configured with a minimum of complexity. Simplicity should be mastered 10 before you get too deeply into complexities. Let's get moving, we have work to do. 11 </p><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2526817"></a>Requirements and Notes</h2></div></div></div><p> 12 Successful completion of this chapter requires two Microsoft Windows 9x/Me Workstations, 13 as well as two Microsoft Windows XP Professional Workstations, each equipped with an Ethernet 14 card connected using a hub. Also required is one additional server (either Windows 15 NT4 Server, Windows 2000 Server, or a Samba-3 on UNIX/Linux server) running a network 16 sniffer and analysis application (ethereal is a good choice). All work should be undertaken 17 on a quiet network where there is no other traffic. It is best to use a dedicated hub 18 with only the machines under test connected at the time of the exercises. 19 </p><p><a class="indexterm" name="id2526848"></a> 20 Ethereal has become the network protocol analyzer of choice for many network administrators. 21 You may find more information regarding this tool from the 22 <a href="http://www.ethereal.com" target="_top">Ethereal</a> Web site. Ethereal installation 23 files for Windows may be obtained from the Ethereal Web site. Ethereal is provided with 24 SUSE and Red Hat Linux distributions, as well as many other Linux distributions. It may 25 not be installed on your system by default. If it is not installed, you may also need 26 to install the <span><b class="command">libpcap </b></span> software before you can install or use Ethereal. 27 Please refer to the instructions for your operating system or to the Ethereal Web site 28 for information regarding the installation and operation of Ethereal. 29 </p><p> 30 To obtain <span><b class="command">ethereal</b></span> for your system, please visit the Ethereal 31 <a href="http://www.ethereal.com/download.html#binaries" target="_top">download site.</a> 32 </p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p> 33 The successful completion of this chapter requires that you capture network traffic 34 using <span><b class="command">ethereal</b></span>. It is recommended that you use a hub, not an 35 etherswitch. It is necessary for the device used to act as a repeater, not as a 36 filter. Ethernet switches may filter out traffic that is not directed at the machine 37 that is used to monitor traffic; this would not allow you to complete the projects. 38 </p></div><p> 39 <a class="indexterm" name="id2526917"></a> 40 Do not worry too much if you do not have access to all this equipment; network captures 41 from the exercises are provided on the enclosed CD-ROM. This makes it possible to dive directly 42 into the analytical part of the exercises if you so desire. 43 </p><p><a class="indexterm" name="id2526932"></a><a class="indexterm" name="id2526944"></a> 44 Please do not be alarmed at the use of a high-powered analysis tool (ethereal) in this 45 first chapter. We expose you only to a minimum of detail necessary to complete 46 the exercises in this chapter. If you choose to use any other network sniffer and protocol 47 analysis tool, be advised that it may not allow you to examine the contents of 48 recently added security protocols used by Windows 200x/XP. 49 </p><p> 50 You could just skim through the exercises and try to absorb the key points made. 51 The exercises provide all the information necessary to convince the die-hard network 52 engineer. You possibly do not require so much convincing and may just want to move on, 53 in which case you should at least read <a href="primer.html#chap01conc" title="Dissection and Discussion">???</a>. 54 </p><p> 55 <a href="primer.html#chap01qa" title="Questions and Answers">???</a> also provides useful information 56 that may help you to avoid significantly time-consuming networking problems. 57 </p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2526988"></a>Introduction</h2></div></div></div><p> 58 The purpose of this chapter is to create familiarity with key aspects of Microsoft Windows 59 network computing. If you want a solid technical grounding, do not gloss over these exercises. 60 The points covered are recurrent issues on the Samba mailing lists. 61 </p><p><a class="indexterm" name="id2527002"></a> 62 You can see from these exercises that Windows networking involves quite a lot of network 63 broadcast traffic. You can look into the contents of some packets, but only to see 64 some particular information that the Windows client sends to a server in the course of 65 establishing a network connection. 66 </p><p> 67 To many people, browsing is everything that happens when one uses Microsoft Internet Explorer. 68 It is only when you start looking at network traffic and noting the protocols 69 and types of information that are used that you can begin to appreciate the complexities of 70 Windows networking and, more importantly, what needs to be configured so that it can work. 71 Detailed information regarding browsing is provided in the recommended 72 preparatory reading. 73 </p><p> 74 Recommended preparatory reading: <span class="emphasis"><em>The Official Samba-3 HOWTO and Reference Guide</em></span> (TOSHARG) 75 Chapter 9, “<span class="quote"><span class="emphasis"><em>Network Browsing,</em></span></span>” and Chapter 3, “<span class="quote"><span class="emphasis"><em>Server Types and 76 Security Modes.</em></span></span>” 77 </p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2527050"></a>Assignment Tasks</h3></div></div></div><p><a class="indexterm" name="id2527057"></a> 78 You are about to witness how Microsoft Windows computer networking functions. The 79 exercises step through identification of how a client machine establishes a 80 connection to a remote Windows server. You observe how Windows machines find 81 each other (i.e., how browsing works), and how the two key types of user identification 82 (share mode security and user mode security) are affected. 83 </p><p><a class="indexterm" name="id2527075"></a> 84 The networking protocols used by MS Windows networking when working with Samba 85 use TCP/IP as the transport protocol. The protocols that are specific to Windows 86 networking are encapsulated in TCP/IP. The network analyzer we use (ethereal) 87 is able to show you the contents of the TCP/IP packets (or messages). 88 </p><div class="procedure"><a name="chap01tasks"></a><p class="title"><b>Procedure�1.1.�Chapter 1 Tasks</b></p><ol type="1"><li><p><a class="indexterm" name="id2527110"></a><a class="indexterm" name="id2527121"></a><a class="indexterm" name="id2527129"></a> 89 Examine network traces to witness SMB broadcasts, host announcements, 90 and name resolution processes. 91 </p></li><li><p> 92 Examine network traces to witness how share mode security functions. 93 </p></li><li><p> 94 Examine network traces to witness the use of user mode security. 95 </p></li><li><p> 96 Review traces of network logons for a Windows 9x/Me client as well as 97 a Domain logon for a Windows XP Professional client. 98 </p></li></ol></div></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2527169"></a>Exercises</h2></div></div></div><p> 99 <a class="indexterm" name="id2527177"></a> 100 You are embarking on a course of discovery. The first part of the exercise requires 101 two MS Windows 9x/Me systems. We called one machine <tt class="constant">WINEPRESSME</tt> and the 102 other <tt class="constant">MILGATE98</tt>. Each needs an IP address; we used <tt class="literal">10.1.1.10</tt> 103 and <tt class="literal">10.1.1.11</tt>. The test machines need to be networked via a <span class="emphasis"><em>hub</em></span>. A UNIX/Linux 104 machine is required to run <span><b class="command">ethereal</b></span> to enable the network activity to be captured. 105 It is important that the machine from which network activity is captured must not interfere with 106 the operation of the Windows workstations. It is helpful for this machine to be passive (does not 107 send broadcast information) to the network. 108 </p><p> 109 For these exercises, our test environment consisted of a SUSE 9.2 Professional Linux Workstation running 110 VMWare 4.5. The following VMWare images were prepared: 111 </p><div class="itemizedlist"><ul type="disc"><li><p>Windows 98 name: MILGATE98.</p></li><li><p>Windows Me name: WINEPRESSME.</p></li><li><p>Windows XP Professional name: LightrayXP.</p></li><li><p>Samba-3.0.12 running on a SUSE Enterprise Linux 9.</p></li></ul></div><p> 112 Choose a workgroup name (MIDEARTH) for each exercise. 113 </p><p> 114 <a class="indexterm" name="id2527267"></a> 115 The network captures provided on the CD-ROM at the back of this book were captured using <tt class="constant">ethereal</tt> 116 version <tt class="literal">0.10.6</tt>. A later version suffices without problems, but an earlier version may not 117 expose all the information needed. Each capture file has been decoded and listed as a trace file. A summary of all 118 packets has also been included. This makes it possible for you to do all the studying you like without the need to 119 perform the time-consuming equipment configuration and test work. This is a good time to point out the value 120 that can be derived from this book really does warrant your taking sufficient time to practice each exercise with 121 care and attention to detail. 122 </p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2527295"></a>Single Machine Broadcast Activity</h3></div></div></div><p> 123 In this section, we start a single Windows 9x/Me machine, then monitor network activity for 30 minutes. 124 </p><div class="procedure"><ol type="1"><li><p> 125 Start the machine from which network activity will be monitored (using <span><b class="command">ethereal</b></span>). 126 Launch <span><b class="command">ethereal</b></span>, click 127 <span class="guimenu">Capture</span>-><span class="guimenuitem">Start</span>. 128 </p><p> 129 Click the following: 130 </p><div class="orderedlist"><ol type="1"><li><p>Update list of packets in real time</p></li><li><p>Automatic scrolling in live capture</p></li><li><p>Enable MAC name resolution</p></li><li><p>Enable network name resolution</p></li><li><p>Enable transport name resolution</p></li></ol></div><p> 131 Click <span class="guibutton">OK</span>. 132 </p></li><li><p> 133 Start the Windows 9x/Me machine to be monitored. Let it run for a full 30 minutes. While monitoring, 134 do not press any keyboard keys, do not click any on-screen icons or menus; and do not answer any dialog boxes. 135 </p></li><li><p> 136 At the conclusion of 30 minutes, stop the capture. Save the capture to a file so you can go back to it later. 137 Leave this machine running in preparation for the task in <a href="primer.html#secondmachine" title="Second Machine Startup Broadcast Interaction">???</a>. 138 </p></li><li><p> 139 Analyze the capture. Identify each discrete message type that was captured. Note what transport protocol 140 was used. Identify the timing between messages of identical types. 141 </p></li></ol></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2527425"></a>Findings</h4></div></div></div><p> 142 The summary of the first 10 minutes of the packet capture should look like <a href="primer.html#pktcap01" title="Figure�1.1.�Windows Me Broadcasts The First 10 Minutes">???</a>. 143 A screenshot of a later stage of the same capture is shown in <a href="primer.html#pktcap02" title="Figure�1.2.�Windows Me Later Broadcast Sample">???</a>. 144 </p><div class="figure"><a name="pktcap01"></a><p class="title"><b>Figure�1.1.�Windows Me Broadcasts The First 10 Minutes</b></p><div class="mediaobject"><img src="images/WINREPRESSME-Capture.png" width="216" alt="Windows Me Broadcasts The First 10 Minutes"></div></div><div class="figure"><a name="pktcap02"></a><p class="title"><b>Figure�1.2.�Windows Me Later Broadcast Sample</b></p><div class="mediaobject"><img src="images/WINREPRESSME-Capture2.png" width="226.8" alt="Windows Me Later Broadcast Sample"></div></div><p><a class="indexterm" name="id2527535"></a><a class="indexterm" name="id2527547"></a> 145 Broadcast messages observed are shown in <a href="primer.html#capsstats01" title="Table�1.1.�Windows Me Startup Broadcast Capture Statistics">???</a>. 146 Actual observations vary a little, but not by much. 147 Early in the startup process, the Windows Me machine broadcasts its name for two reasons; 148 first to ensure that its name would not result in a name clash, and second to establish its 149 presence with the Local Master Browser (LMB). 150 </p><div class="table"><a name="capsstats01"></a><p class="title"><b>Table�1.1.�Windows Me Startup Broadcast Capture Statistics</b></p><table summary="Windows Me Startup Broadcast Capture Statistics" border="1"><colgroup><col align="left"><col align="center"><col align="center"><col align="left"></colgroup><thead><tr><th align="left">Message</th><th align="center">Type</th><th align="center">Num</th><th align="left">Notes</th></tr></thead><tbody><tr><td align="left">WINEPRESSME<00></td><td align="center">Reg</td><td align="center">8</td><td align="left">4 lots of 2, 0.6 sec apart.</td></tr><tr><td align="left">WINEPRESSME<03></td><td align="center">Reg</td><td align="center">8</td><td align="left">4 lots of 2, 0.6 sec apart.</td></tr><tr><td align="left">WINEPRESSME<20></td><td align="center">Reg</td><td align="center">8</td><td align="left">4 lots of 2, 0.75 sec apart.</td></tr><tr><td align="left">MIDEARTH<00></td><td align="center">Reg</td><td align="center">8</td><td align="left">4 lots of 2, 0.75 sec apart.</td></tr><tr><td align="left">MIDEARTH<1d></td><td align="center">Reg</td><td align="center">8</td><td align="left">4 lots of 2, 0.75 sec apart.</td></tr><tr><td align="left">MIDEARTH<1e></td><td align="center">Reg</td><td align="center">8</td><td align="left">4 lots of 2, 0.75 sec apart.</td></tr><tr><td align="left">MIDEARTH<1b></td><td align="center">Qry</td><td align="center">84</td><td align="left">300 sec apart at stable operation.</td></tr><tr><td align="left">__MSBROWSE__</td><td align="center">Reg</td><td align="center">8</td><td align="left">Registered after winning election to Browse Master.</td></tr><tr><td align="left">JHT<03></td><td align="center">Reg</td><td align="center">8</td><td align="left">4 x 2. This is the name of the user that logged onto Windows.</td></tr><tr><td align="left">Host Announcement WINEPRESSME</td><td align="center">Ann</td><td align="center">2</td><td align="left">Observed at 10 sec.</td></tr><tr><td align="left">Domain/Workgroup Announcement MIDEARTH</td><td align="center">Ann</td><td align="center">18</td><td align="left">300 sec apart at stable operation.</td></tr><tr><td align="left">Local Master Announcement WINEPRESSME</td><td align="center">Ann</td><td align="center">18</td><td align="left">300 sec apart at stable operation.</td></tr><tr><td align="left">Get Backup List Request</td><td align="center">Qry</td><td align="center">12</td><td align="left">6 x 2 early in startup, 0.5 sec apart.</td></tr><tr><td align="left">Browser Election Request</td><td align="center">Ann</td><td align="center">10</td><td align="left">5 x 2 early in startup.</td></tr><tr><td align="left">Request Announcement WINEPRESSME</td><td align="center">Ann</td><td align="center">4</td><td align="left">Early in startup.</td></tr></tbody></table></div><p><a class="indexterm" name="id2527892"></a><a class="indexterm" name="id2527900"></a> 151 From the packet trace, it should be noted that no messages were propagated over TCP/IP; 152 all employed UDP/IP. When steady state operation has been achieved, there is a cycle 153 of various announcements, re-election of a browse master, and name queries. These create 154 the symphony of announcements by which network browsing is made possible. 155 </p><p><a class="indexterm" name="id2527917"></a> 156 For detailed information regarding the precise behavior of the CIFS/SMB protocols, the 157 reader is referred to the book “<span class="quote"><span class="emphasis"><em>Implementing CIFS: The Common Internet File System,</em></span></span>” 158 by Christopher Hertel, Publisher: Prentice Hall PTR, ISBN: 013047116X. 159 </p></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="secondmachine"></a>Second Machine Startup Broadcast Interaction</h3></div></div></div><p> 160 At this time, the machine you used to capture the single system startup trace should still be running. 161 The objective of this task is to identify the interaction of two machines in respect to broadcast activity. 162 </p><div class="procedure"><ol type="1"><li><p> 163 On the machine from which network activity will be monitored (using <span><b class="command">ethereal</b></span>), 164 launch <span><b class="command">ethereal</b></span> and click 165 <span class="guimenu">Capture</span>-><span class="guimenuitem">Start</span>. 166 </p><p> 167 Click: 168 </p><div class="orderedlist"><ol type="1"><li><p>Update list of packets in real time</p></li><li><p>Automatic scrolling in live capture</p></li><li><p>Enable MAC name resolution</p></li><li><p>Enable network name resolution</p></li><li><p>Enable transport name resolution</p></li></ol></div><p> 169 Click <span class="guibutton">OK</span>. 170 </p></li><li><p> 171 Start the second Windows 9x/Me machine. Let it run for 15-20 minutes. While monitoring, do not press 172 any keyboard keys, do not click any on-screen icons or menus, and do not answer any dialog boxes. 173 </p></li><li><p> 174 At the conclusion of the capture time, stop the capture. Be sure to save the captured data so you 175 can examine the network data capture again at a later date should that be necessary. 176 </p></li><li><p> 177 Analyze the capture trace, taking note of the transport protocols used, the types of messages observed, 178 and what interaction took place between the two machines. Leave both machines running for the next task. 179 </p></li></ol></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2528067"></a>Findings</h4></div></div></div><p> 180 <a href="primer.html#capsstats02" title="Table�1.2.�Second Machine (Windows 98) Capture Statistics">???</a> summarizes capture statistics observed. As in the previous case, 181 all announcements used UDP/IP broadcasts. Also, as was observed with the last example, the second 182 Windows 9x/Me machine broadcasts its name on startup to ensure that there exists no name clash 183 (i.e., the name is already registered by another machine) on the network segment. Those wishing 184 to explore the inner details of the precise mechanism of how this functions should refer to 185 the book “<span class="quote"><span class="emphasis"><em>Implementing CIFS: The Common Internet File System,</em></span></span>” referred to previously. 186 </p><div class="table"><a name="capsstats02"></a><p class="title"><b>Table�1.2.�Second Machine (Windows 98) Capture Statistics</b></p><table summary="Second Machine (Windows 98) Capture Statistics" border="1"><colgroup><col align="left"><col align="center"><col align="center"><col align="left"></colgroup><thead><tr><th align="left">Message</th><th align="center">Type</th><th align="center">Num</th><th align="left">Notes</th></tr></thead><tbody><tr><td align="left">MILGATE98<00></td><td align="center">Reg</td><td align="center">8</td><td align="left">4 lots of 2, 0.6 sec apart.</td></tr><tr><td align="left">MILGATE98<03></td><td align="center">Reg</td><td align="center">8</td><td align="left">4 lots of 2, 0.6 sec apart.</td></tr><tr><td align="left">MILGATE98<20></td><td align="center">Reg</td><td align="center">8</td><td align="left">4 lots of 2, 0.75 sec apart.</td></tr><tr><td align="left">MIDEARTH<00></td><td align="center">Reg</td><td align="center">8</td><td align="left">4 lots of 2, 0.75 sec apart.</td></tr><tr><td align="left">MIDEARTH<1d></td><td align="center">Reg</td><td align="center">8</td><td align="left">4 lots of 2, 0.75 sec apart.</td></tr><tr><td align="left">MIDEARTH<1e></td><td align="center">Reg</td><td align="center">8</td><td align="left">4 lots of 2, 0.75 sec apart.</td></tr><tr><td align="left">MIDEARTH<1b></td><td align="center">Qry</td><td align="center">18</td><td align="left">900 sec apart at stable operation.</td></tr><tr><td align="left">JHT<03></td><td align="center">Reg</td><td align="center">2</td><td align="left">This is the name of the user that logged onto Windows.</td></tr><tr><td align="left">Host Announcement MILGATE98</td><td align="center">Ann</td><td align="center">14</td><td align="left">Every 120 sec.</td></tr><tr><td align="left">Domain/Workgroup Announcement MIDEARTH</td><td align="center">Ann</td><td align="center">6</td><td align="left">900 sec apart at stable operation.</td></tr><tr><td align="left">Local Master Announcement WINEPRESSME</td><td align="center">Ann</td><td align="center">6</td><td align="left">Insufficient detail to determine frequency.</td></tr></tbody></table></div><p> 187 <a class="indexterm" name="id2528352"></a> 188 <a class="indexterm" name="id2528359"></a> 189 <a class="indexterm" name="id2528366"></a> 190 Observation of the contents of Host Announcements, Domain/Workgroup Announcements, 191 and Local Master Announcements is instructive. These messages convey a significant 192 level of detail regarding the nature of each machine that is on the network. An example 193 dissection of a Host Announcement is given in <a href="primer.html#hostannounce" title="Figure�1.3.�Typical Windows 9x/Me Host Announcement">???</a>. 194 </p><div class="figure"><a name="hostannounce"></a><p class="title"><b>Figure�1.3.�Typical Windows 9x/Me Host Announcement</b></p><div class="mediaobject"><img src="images/HostAnnouncment.png" width="221.4" alt="Typical Windows 9x/Me Host Announcement"></div></div></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2528431"></a>Simple Windows Client Connection Characteristics</h3></div></div></div><p> 195 The purpose of this exercise is to discover how Microsoft Windows clients create (establish) 196 connections with remote servers. The methodology involves analysis of a key aspect of how 197 Windows clients access remote servers: the session setup protocol. 198 </p><div class="procedure"><ol type="1"><li><p> 199 Configure a Windows 9x/Me machine (MILGATE98) with a share called <tt class="constant">Stuff</tt>. 200 Create a <i class="parameter"><tt>Full Access</tt></i> control password on this share. 201 </p></li><li><p> 202 Configure another Windows 9x/Me machine (WINEPRESSME) as a client. Make sure that it exports 203 no shared resources. 204 </p></li><li><p> 205 Start both Windows 9x/Me machines and allow them to stabilize for 10 minutes. Log on to both 206 machines using a user name (JHT) of your choice. Wait approximately two minutes before proceeding. 207 </p></li><li><p> 208 Start ethereal (or the network sniffer of your choice). 209 </p></li><li><p> 210 From the WINEPRESSME machine, right-click <span class="guimenu">Network Neighborhood</span>, select 211 <span class="guimenuitem">Explore</span>, select 212 <span class="guimenuitem">My Network Places</span>-><span class="guimenuitem">Entire Network</span>-><span class="guimenuitem">MIDEARTH</span>-><span class="guimenuitem">MILGATE98</span>-><span class="guimenuitem">Stuff</span>. 213 Enter the password you set for the <tt class="constant">Full Control</tt> mode for the 214 <tt class="constant">Stuff</tt> share. 215 </p></li><li><p> 216 When the share called <tt class="constant">Stuff</tt> is being displayed, stop the capture. 217 Save the captured data in case it is needed for later analysis. 218 </p></li><li><p> 219 <a class="indexterm" name="id2528572"></a> 220 From the top of the packets captured, scan down to locate the first packet that has 221 interpreted as <tt class="constant">Session Setup AndX, User: anonymous; Tree Connect AndX, 222 Path: \\MILGATE98\IPC$</tt>. 223 </p></li><li><p><a class="indexterm" name="id2528591"></a><a class="indexterm" name="id2528599"></a> 224 In the dissection (analysis) panel, expand the <tt class="constant">SMB, Session Setup AndX Request, 225 and Tree Connect AndX Request</tt>. Examine both operations. Identify the name of 226 the user Account and what password was used. The Account name should be empty. 227 This is a <tt class="constant">NULL</tt> session setup packet. 228 </p></li><li><p> 229 Return to the packet capture sequence. There will be a number of packets that have been 230 decoded of the type <tt class="constant">Session Setup AndX</tt>. Locate the last such packet 231 that was targeted at the <tt class="constant">\\MILGATE98\IPC$</tt> service. 232 </p></li><li><p> 233 <a class="indexterm" name="id2528644"></a> 234 <a class="indexterm" name="id2528651"></a> 235 Dissect this packet as per the one above. This packet should have a password length 236 of 24 (characters) and should have a password field, the contents of which is a 237 long hexadecimal number. Observe the name in the Account field. This is a User Mode 238 session setup packet. 239 </p></li></ol></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2528665"></a>Findings and Comments</h4></div></div></div><p> 240 <a class="indexterm" name="id2528673"></a> 241 The <tt class="constant">IPC$</tt> share serves a vital purpose<sup>[<a name="id2528684" href="#ftn.id2528684">1</a>]</sup> 242 in SMB/CIFS based networking. A Windows client connects to this resource to obtain the list of 243 resources that are available on the server. The server responds with the shares and print queues that 244 are available. In most but not all cases, the connection is made with a <tt class="constant">NULL</tt> 245 username and a <tt class="constant">NULL</tt> password. 246 </p><p> 247 <a class="indexterm" name="id2528705"></a> 248 The two packets examined are material evidence with respect to how Windows clients may 249 interoperate with Samba. Samba requires every connection setup to be authenticated using 250 valid UNIX account credentials (UID/GID). This means that even a <tt class="constant">NULL</tt> 251 session setup can be established only by automatically mapping it to a valid UNIX 252 account. 253 </p><p> 254 <a class="indexterm" name="id2528724"></a><a class="indexterm" name="id2528730"></a> 255 <a class="indexterm" name="id2528739"></a> 256 Samba has a special name for the <tt class="constant">NULL</tt>, or empty, user account. 257 It calls that the <a class="indexterm" name="id2528751"></a>guest account. The 258 default value of this parameter is <tt class="constant">nobody</tt>; however, this can be 259 changed to map the function of the guest account to any other UNIX identity. Some 260 UNIX administrators prefer to map this account to the system default anonymous 261 FTP account. A sample NULL Session Setup AndX packet dissection is shown in 262 <a href="primer.html#nullconnect" title="Figure�1.4.�Typical Windows 9x/Me NULL SessionSetUp AndX Request">???</a>. 263 </p><div class="figure"><a name="nullconnect"></a><p class="title"><b>Figure�1.4.�Typical Windows 9x/Me NULL SessionSetUp AndX Request</b></p><div class="mediaobject"><img src="images/NullConnect.png" width="221.4" alt="Typical Windows 9x/Me NULL SessionSetUp AndX Request"></div></div><p> 264 <a class="indexterm" name="id2528820"></a> 265 <a class="indexterm" name="id2528826"></a> 266 <a class="indexterm" name="id2528833"></a> 267 When a UNIX/Linux system does not have a <tt class="constant">nobody</tt> user account 268 (<tt class="filename">/etc/passwd</tt>), the operation of the <tt class="constant">NULL</tt> 269 account cannot validate and thus connections that utilize the guest account 270 fail. This breaks all ability to browse the Samba server and is a common 271 problem reported on the Samba mailing list. A sample User Mode Session Setup AndX 272 is shown in <a href="primer.html#userconnect" title="Figure�1.5.�Typical Windows 9x/Me User SessionSetUp AndX Request">???</a>. 273 </p><div class="figure"><a name="userconnect"></a><p class="title"><b>Figure�1.5.�Typical Windows 9x/Me User SessionSetUp AndX Request</b></p><div class="mediaobject"><img src="images/UserConnect.png" width="221.4" alt="Typical Windows 9x/Me User SessionSetUp AndX Request"></div></div><p> 274 <a class="indexterm" name="id2528911"></a> 275 The User Mode connection packet contains the account name and the domain name. 276 The password is provided in Microsoft encrypted form, and its length is shown 277 as 24 characters. This is the length of Microsoft encrypted passwords. 278 </p></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2528925"></a>Windows 200x/XP Client Interaction with Samba-3</h3></div></div></div><p> 279 By now you may be asking, “<span class="quote"><span class="emphasis"><em>Why did you choose to work with Windows 9x/Me?</em></span></span>” 280 </p><p> 281 First, we want to demonstrate the simple case. This book is not intended to be a detailed treatise 282 on the Windows networking protocols, but rather to provide prescriptive guidance for deployment of Samba. 283 Second, by starting out with the simple protocol, it can be demonstrated that the more complex case mostly 284 follows the same principles. 285 </p><p> 286 The following exercise demonstrates the case that even MS Windows XP Professional with up-to-date service 287 updates also uses the <tt class="constant">NULL</tt> account, as well as user accounts. Simply follow the procedure 288 to complete this exercise. 289 </p><p> 290 To complete this exercise, you need a Windows XP Professional client that has been configured as 291 a Domain Member of either a Samba controlled domain or a Windows NT4 or 200x Active Directory domain. 292 Here we do not provide details for how to configure this, as full coverage is provided later in this book. 293 </p><div class="procedure"><ol type="1"><li><p> 294 Start your Domain Controller. Also, start the ethereal monitoring machine, launch ethereal, 295 and then wait for the next step to complete. 296 </p></li><li><p> 297 Start the Windows XP Client and wait five minutes before proceeding. 298 </p></li><li><p> 299 On the machine from which network activity will be monitored (using <span><b class="command">ethereal</b></span>), 300 launch <span><b class="command">ethereal</b></span> and click 301 <span class="guimenu">Capture</span>-><span class="guimenuitem">Start</span>. 302 </p><p> 303 Click: 304 </p><div class="orderedlist"><ol type="1"><li><p>Update list of packets in real time</p></li><li><p>Automatic scrolling in live capture</p></li><li><p>Enable MAC name resolution</p></li><li><p>Enable network name resolution</p></li><li><p>Enable transport name resolution</p></li></ol></div><p> 305 Click <span class="guibutton">OK</span>. 306 </p></li><li><p> 307 On the Windows XP Professional client: Press <span class="guimenu">Ctrl-Alt-Delete</span> to bring 308 up the domain logon screen. Log in using valid credentials for a domain user account. 309 </p></li><li><p> 310 Now proceed to connect to the Domain Controller as follows: 311 <span class="guimenu">Start</span>-><span class="guimenuitem">(right-click) My Network Places</span>-><span class="guimenuitem">Explore</span>-><span class="guimenuitem">{Left Panel} [+] Entire Network</span>-><span class="guimenuitem">{Left Panel} [+] Microsoft Windows Network</span>-><span class="guimenuitem">{Left Panel} [+] Midearth</span>-><span class="guimenuitem">{Left Panel} [+] Frodo</span>-><span class="guimenuitem">{Left Panel} [+] data</span>. Close the explorer window. 312 </p><p> 313 In this step, our domain name is <tt class="constant">Midearth</tt>, the domain controller is called 314 <tt class="constant">Frodo</tt>, and we have connected to a share called <tt class="constant">data</tt>. 315 </p></li><li><p> 316 Stop the capture on the <span><b class="command">ethereal</b></span> monitoring machine. Be sure to save the captured data 317 to a file so that you can refer to it again later. 318 </p></li><li><p> 319 If desired, the Windows XP Professional client and the Domain Controller are no longer needed for exercises 320 in this chapter. 321 </p></li><li><p> 322 <a class="indexterm" name="id2529191"></a> 323 <a class="indexterm" name="id2529198"></a> 324 From the top of the packets captured, scan down to locate the first packet that has 325 interpreted as <tt class="constant">Session Setup AndX Request, NTLMSSP_AUTH</tt>. 326 </p></li><li><p> 327 <a class="indexterm" name="id2529219"></a> 328 <a class="indexterm" name="id2529225"></a> 329 <a class="indexterm" name="id2529232"></a> 330 In the dissection (analysis) panel, expand the <tt class="constant">SMB, Session Setup AndX Request</tt>. 331 Expand the packet decode information, beginning at the <tt class="constant">Security Blob:</tt> 332 entry. Expand the <tt class="constant">GSS-API -> SPNEGO -> netTokenTarg -> responseToken -> NTLMSSP</tt> 333 keys. This should reveal that this is a <tt class="constant">NULL</tt> session setup packet. 334 The <tt class="constant">User name: NULL</tt> indicates this. An example decode is shown in 335 <a href="primer.html#XPCap01" title="Figure�1.6.�Typical Windows XP NULL Session Setup AndX Request">???</a>. 336 </p></li><li><p> 337 Return to the packet capture sequence. There will be a number of packets that have been 338 decoded of the type <tt class="constant">Session Setup AndX Request</tt>. Click the last such packet that 339 has been decoded as <tt class="constant">Session Setup AndX Request, NTLMSSP_AUTH</tt>. 340 </p></li><li><p> 341 <a class="indexterm" name="id2529295"></a> 342 In the dissection (analysis) panel, expand the <tt class="constant">SMB, Session Setup AndX Request</tt>. 343 Expand the packet decode information, beginning at the <tt class="constant">Security Blob:</tt> 344 entry. Expand the <tt class="constant">GSS-API -> SPNEGO -> netTokenTarg -> responseToken -> NTLMSSP</tt> 345 keys. This should reveal that this is a <tt class="constant">User Mode</tt> session setup packet. 346 The <tt class="constant">User name: jht</tt> indicates this. An example decode is shown in 347 <a href="primer.html#XPCap02" title="Figure�1.7.�Typical Windows XP User Session Setup AndX Request">???</a>. In this case the user name was <tt class="constant">jht</tt>. This packet 348 decode includes the <tt class="constant">Lan Manager Response:</tt> and the <tt class="constant">NTLM Response:</tt>. 349 The value of these two parameters is the Microsoft encrypted password hashes, respectively, the LanMan 350 password and then the NT (case-preserving) password hash. 351 </p></li><li><p> 352 <a class="indexterm" name="id2529356"></a> 353 <a class="indexterm" name="id2529362"></a> 354 The passwords are 24 characters long hexadecimal numbers. This packet confirms that this is a User Mode 355 session setup packet. 356 </p></li></ol></div><div class="figure"><a name="XPCap01"></a><p class="title"><b>Figure�1.6.�Typical Windows XP NULL Session Setup AndX Request</b></p><div class="mediaobject"><img src="images/WindowsXP-NullConnection.png" width="270" alt="Typical Windows XP NULL Session Setup AndX Request"></div></div><div class="figure"><a name="XPCap02"></a><p class="title"><b>Figure�1.7.�Typical Windows XP User Session Setup AndX Request</b></p><div class="mediaobject"><img src="images/WindowsXP-UserConnection.png" width="270" alt="Typical Windows XP User Session Setup AndX Request"></div></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2529460"></a>Discussion</h4></div></div></div><p><a class="indexterm" name="id2529467"></a> 357 This exercise demonstrates that, while the specific protocol for the Session Setup AndX is handled 358 in a more sophisticated manner by recent MS Windows clients, the underlying rules or principles 359 remain the same. Thus it is demonstrated that MS Windows XP Professional clients still use a 360 <tt class="constant">NULL-Session</tt> connection to query and locate resources on an advanced network 361 technology server (one using Windows NT4/200x or Samba). It also demonstrates that an authenticated 362 connection must be made before resources can be used. 363 </p></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2529492"></a>Conclusions to Exercises</h3></div></div></div><p> 364 In summary, the following points have been established in this chapter: 365 </p><div class="itemizedlist"><ul type="disc"><li><p> 366 When NetBIOS over TCP/IP protocols are enabled, MS Windows networking employs broadcast 367 oriented messaging protocols to provide knowledge of network services. 368 </p></li><li><p> 369 Network browsing protocols query information stored on Browse Masters that manage 370 information provided by NetBIOS Name Registrations and by way of on-going Host 371 Announcements and Workgroup Announcements. 372 </p></li><li><p> 373 All Samba servers must be configured with a mechanism for mapping the <tt class="constant">NULL-Session</tt> 374 to a valid but non-privileged UNIX system account. 375 </p></li><li><p> 376 The use of Microsoft encrypted passwords is built right into the fabric of Windows 377 networking operations. Such passwords cannot be provided from the UNIX <tt class="filename">/etc/passwd</tt> 378 database and thus must be stored elsewhere on the UNIX system in a manner that Samba can 379 use. Samba-2.x permitted such encrypted passwords to be stored in the <tt class="constant">smbpasswd</tt> 380 file or in an LDAP database. Samba-3 permits that use of multiple different <i class="parameter"><tt>passdb backend</tt></i> 381 databases, in concurrent deploy. Refer to <span class="emphasis"><em>TOSHARG</em></span>, Chapter 10, “<span class="quote"><span class="emphasis"><em>Account Information Databases.</em></span></span>” 382 </p></li></ul></div></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="chap01conc"></a>Dissection and Discussion</h2></div></div></div><p> 383 <a class="indexterm" name="id2529581"></a> 384 The exercises demonstrate the use of the <tt class="constant">guest</tt> account, the way that 385 MS Windows clients and servers resolve computer names to a TCP/IP address, and how connections 386 between a client and a server are established. 387 </p><p> 388 Those wishing background information regarding NetBIOS name types should refer to 389 the Microsoft Knowledge Base Article 390 <a href="http://support.microsoft.com/support/kb/articles/Q102/78/8.asp" target="_top">Q102878.</a> 391 </p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2529608"></a>Technical Issues</h3></div></div></div><p> 392 <a class="indexterm" name="id2529615"></a> 393 Network browsing involves SMB broadcast announcements, SMB enumeration requests, 394 connections to the <tt class="constant">IPC$</tt> share, share enumerations, and SMB connection 395 setup processes. The use of anonymous connections to a Samba server involve the use of 396 the <i class="parameter"><tt>guest account</tt></i> that must map to a valid UNIX UID. 397 </p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="chap01qa"></a>Questions and Answers</h2></div></div></div><p> 398 The questions and answers given in this section are designed to highlight important aspects of Microsoft 399 Windows networking. 400 </p><div class="qandaset"><dl><dt> <a href="primer.html#id2529659"> 401 What is the significance of the MIDEARTH<1b> type query? 402 </a></dt><dt> <a href="primer.html#id2529706"> 403 What is the significance of the MIDEARTH<1d> type name registration? 404 </a></dt><dt> <a href="primer.html#id2529781"> 405 What is the role and significance of the <01><02>__MSBROWSE__<02><01> 406 name registration? 407 </a></dt><dt> <a href="primer.html#id2529813"> 408 What is the significance of the MIDEARTH<1e> type name registration? 409 </a></dt><dt> <a href="primer.html#id2529844"> 410 guest account 411 What is the significance of the guest account in smb.conf? 412 </a></dt><dt> <a href="primer.html#id2529917"> 413 Is it possible to reduce network broadcast activity with Samba-3? 414 </a></dt><dt> <a href="primer.html#id2530024"> 415 Can I just use plain-text passwords with Samba? 416 </a></dt><dt> <a href="primer.html#id2530113"> 417 What parameter in the smb.conf file is used to enable the use of encrypted passwords? 418 </a></dt><dt> <a href="primer.html#id2530154"> 419 Is it necessary to specify encrypt passwordsencrypt passwords = Yes 420 when Samba-3 is configured as a Domain Member? 421 </a></dt><dt> <a href="primer.html#id2530180"> 422 Is it necessary to specify a guest account when Samba-3 is configured 423 as a Domain Member server? 424 </a></dt></dl><table border="0" summary="Q and A Set"><col align="left" width="1%"><tbody><tr class="question"><td align="left" valign="top"><a name="id2529659"></a><a name="id2529661"></a><b></b></td><td align="left" valign="top"><p> 425 What is the significance of the MIDEARTH<1b> type query? 426 </p></td></tr><tr class="answer"><td align="left" valign="top"><b></b></td><td align="left" valign="top"><p> 427 <a class="indexterm" name="id2529674"></a> 428 <a class="indexterm" name="id2529683"></a> 429 This is a broadcast announcement by which the Windows machine is attempting to 430 locate a Domain Master Browser (DMB) in the event that it might exist on the network. 431 Refer to <span class="emphasis"><em>TOSHARG</em></span> Chapter 9, Section 9.7, “<span class="quote"><span class="emphasis"><em>Technical Overview of Browsing</em></span></span>” 432 for details regarding the function of the DMB and its role in network browsing. 433 </p></td></tr><tr class="question"><td align="left" valign="top"><a name="id2529706"></a><a name="id2529708"></a><b></b></td><td align="left" valign="top"><p> 434 What is the significance of the MIDEARTH<1d> type name registration? 435 </p></td></tr><tr class="answer"><td align="left" valign="top"><b></b></td><td align="left" valign="top"><p> 436 <a class="indexterm" name="id2529721"></a> 437 <a class="indexterm" name="id2529730"></a> 438 This name registration records the machine IP addresses of the Local Master Browsers (LMBs). 439 Network clients can query this name type to obtain a list of browser servers from the 440 Master Browser. 441 </p><p> 442 The LMB is responsible for monitoring all host announcements on the local network and for 443 collating the information contained within them. Using this information, it can provide answers to other Windows 444 network clients that request information such as: 445 </p><div class="itemizedlist"><ul type="disc"><li><p> 446 The list of machines known to the LMB (i.e., the browse list) 447 </p></li><li><p> 448 The IP addresses of all Domain Controllers known for the Domain 449 </p></li><li><p> 450 The IP addresses of LMBs 451 </p></li><li><p> 452 The IP address of the DMB (if one exists) 453 </p></li><li><p> 454 The IP address of the LMB on the local segment 455 </p></li></ul></div></td></tr><tr class="question"><td align="left" valign="top"><a name="id2529781"></a><a name="id2529783"></a><b></b></td><td align="left" valign="top"><p> 456 What is the role and significance of the <01><02>__MSBROWSE__<02><01> 457 name registration? 458 </p></td></tr><tr class="answer"><td align="left" valign="top"><b></b></td><td align="left" valign="top"><p> 459 <a class="indexterm" name="id2529798"></a> 460 This name is registered by the Browse Master to broadcast and receive domain announcements. 461 Its scope is limited to the local network segment, or subnet. By querying this name type, 462 Master Browsers on networks that have multiple domains can find the names of Master Browsers 463 for each domain. 464 </p></td></tr><tr class="question"><td align="left" valign="top"><a name="id2529813"></a><a name="id2529815"></a><b></b></td><td align="left" valign="top"><p> 465 What is the significance of the MIDEARTH<1e> type name registration? 466 </p></td></tr><tr class="answer"><td align="left" valign="top"><b></b></td><td align="left" valign="top"><p> 467 <a class="indexterm" name="id2529828"></a> 468 This name is registered by all Browse Masters in a domain or workgroup. The registration 469 name type is known as the Browser Election Service. Master Browsers register themselves 470 with this name type so that Domain Master Browsers can locate them to perform cross-subnet 471 browse list updates. This name type is also used to initiate elections for Master Browsers. 472 </p></td></tr><tr class="question"><td align="left" valign="top"><a name="id2529844"></a><a name="id2529846"></a><b></b></td><td align="left" valign="top"><p> 473 <a class="indexterm" name="id2529851"></a> 474 What is the significance of the <i class="parameter"><tt>guest account</tt></i> in smb.conf? 475 </p></td></tr><tr class="answer"><td align="left" valign="top"><b></b></td><td align="left" valign="top"><p> 476 This parameter specifies the default UNIX account to which MS Windows networking 477 NULL session connections are mapped. The default name for the UNIX account used for 478 this mapping is called <tt class="constant">nobody</tt>. If the UNIX/Linux system that 479 is hosting Samba does not have a <tt class="constant">nobody</tt> account and an alternate 480 mapping has not been specified, network browsing will not work at all. 481 </p><p> 482 It should be noted that the <i class="parameter"><tt>guest account</tt></i> is essential to 483 Samba operation. Either the operating system must have an account called <tt class="constant">nobody</tt> 484 or there must be an entry in the <tt class="filename">smb.conf</tt> file with a valid UNIX account. For example, 485 <a class="indexterm" name="id2529907"></a>guest account = ftp. 486 </p></td></tr><tr class="question"><td align="left" valign="top"><a name="id2529917"></a><a name="id2529919"></a><b></b></td><td align="left" valign="top"><p> 487 Is it possible to reduce network broadcast activity with Samba-3? 488 </p></td></tr><tr class="answer"><td align="left" valign="top"><b></b></td><td align="left" valign="top"><p> 489 <a class="indexterm" name="id2529931"></a> 490 <a class="indexterm" name="id2529938"></a> 491 Yes, there are two ways to do this. The first involves use of WINS (See <span class="emphasis"><em>TOSHARG</em></span>, Chapter 9, 492 Section 9.5, “<span class="quote"><span class="emphasis"><em>WINS The Windows Inter-networking Name Server</em></span></span>”), the 493 alternate method involves disabling the use of NetBIOS over TCP/IP. This second method requires 494 a correctly configured DNS server (see <span class="emphasis"><em>TOSHARG</em></span>, Chapter 9, Section 9.3, “<span class="quote"><span class="emphasis"><em>Discussion</em></span></span>”). 495 </p><p> 496 <a class="indexterm" name="id2529973"></a> 497 <a class="indexterm" name="id2529980"></a> 498 <a class="indexterm" name="id2529989"></a> 499 The use of WINS reduces network broadcast traffic. The reduction is greatest when all network 500 clients are configured to operate in <i class="parameter"><tt>Hybrid Mode</tt></i>. This can be effected through 501 use of DHCP to set the NetBIOS node type to type 8 for all network clients. Additionally, it is 502 beneficial to configure Samba to use <a class="indexterm" name="id2530007"></a>name resolve order = wins host cast. 503 </p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p> 504 Use of SMB without NetBIOS is possible only on Windows 200x/XP Professional clients and servers, as 505 well as with Samba-3. 506 </p></div></td></tr><tr class="question"><td align="left" valign="top"><a name="id2530024"></a><a name="id2530026"></a><b></b></td><td align="left" valign="top"><p> 507 Can I just use plain-text passwords with Samba? 508 </p></td></tr><tr class="answer"><td align="left" valign="top"><b></b></td><td align="left" valign="top"><p> 509 Yes, you can configure Samba to use plain-text passwords, though this does create a few problems. 510 </p><p> 511 First, the use of <tt class="filename">/etc/passwd</tt> based plain-text passwords requires that registry 512 modifications be made on all MS Windows client machines to enable plain-text passwords support. This 513 significantly diminishes the security of MS Windows client operation. Many network administrators 514 are bitterly opposed to doing this. 515 </p><p> 516 Second, Microsoft has not maintained plain-text password support since the default setting was made 517 disabling this. When network connections are dropped by the client it is not be possible to re-establish 518 the connection automatically. Users need to log off and then log on again. Plain-text password support 519 may interfere with recent enhancements that are part of the Microsoft move toward a more secure computing 520 environment. 521 </p><p> 522 Samba-3 supports Microsoft encrypted passwords. Be advised not to reintroduce plain-text password handling. 523 Just create user accounts by running: <span><b class="command">smbpasswd -a 'username'</b></span> 524 </p><p> 525 It is not possible to add a user to the <i class="parameter"><tt>passdb backend</tt></i> database unless there is 526 a UNIX system account for that user. On systems that run <span><b class="command">winbindd</b></span> to access the Samba 527 PDC/BDC to provide Windows user and group accounts, the <i class="parameter"><tt>idmap uid, idmap gid</tt></i> ranges 528 set in the <tt class="filename">smb.conf</tt> file provide the local UID/GIDs needed for local identity management purposes. 529 </p></td></tr><tr class="question"><td align="left" valign="top"><a name="id2530113"></a><a name="id2530115"></a><b></b></td><td align="left" valign="top"><p> 530 What parameter in the <tt class="filename">smb.conf</tt> file is used to enable the use of encrypted passwords? 531 </p></td></tr><tr class="answer"><td align="left" valign="top"><b></b></td><td align="left" valign="top"><p> 532 The parameter in the <tt class="filename">smb.conf</tt> file that controls this behavior is known as <i class="parameter"><tt>encrypt 533 passwords</tt></i>. The default setting for this in Samba-3 is <tt class="constant">Yes (Enabled)</tt>. 534 </p></td></tr><tr class="question"><td align="left" valign="top"><a name="id2530154"></a><a name="id2530156"></a><b></b></td><td align="left" valign="top"><p> 535 Is it necessary to specify <a class="indexterm" name="id2530161"></a>encrypt passwords = Yes 536 when Samba-3 is configured as a Domain Member? 537 </p></td></tr><tr class="answer"><td align="left" valign="top"><b></b></td><td align="left" valign="top"><p> 538 No. This is the default behavior. 539 </p></td></tr><tr class="question"><td align="left" valign="top"><a name="id2530180"></a><a name="id2530182"></a><b></b></td><td align="left" valign="top"><p> 540 Is it necessary to specify a <i class="parameter"><tt>guest account</tt></i> when Samba-3 is configured 541 as a Domain Member server? 542 </p></td></tr><tr class="answer"><td align="left" valign="top"><b></b></td><td align="left" valign="top"><p> 543 Yes. This is a local function on the server. The default setting is to use the UNIX account 544 <tt class="constant">nobody</tt>. If this account does not exist on the UNIX server, then it is 545 necessary to provide a <a class="indexterm" name="id2530207"></a>guest account = an_account, 546 where <tt class="constant">an_account</tt> is a valid local UNIX user account. 547 </p></td></tr></tbody></table></div></div><div class="footnotes"><br><hr width="100" align="left"><div class="footnote"><p><sup>[<a name="ftn.id2528684" href="#id2528684">1</a>] </sup>TOSHARG, Sect 4.5.1</p></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="preface.html">Prev</a>�</td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right">�<a accesskey="n" href="simple.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Preface�</td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top">�Chapter�2.�No Frills Samba Servers</td></tr></table></div></body></html> 548
