1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Chapter�6.�A Distributed 2000-User Network</title><link rel="stylesheet" href="../samba.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.74.0"><link rel="home" href="index.html" title="Samba-3 by Example"><link rel="up" href="ExNetworks.html" title="Part�I.�Example Network Configurations"><link rel="prev" href="happy.html" title="Chapter�5.�Making Happy Users"><link rel="next" href="DMSMig.html" title="Part�II.�Domain Members, Updating Samba and Migration"></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�6.�A Distributed 2000-User Network</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="happy.html">Prev</a>�</td><th width="60%" align="center">Part�I.�Example Network Configurations</th><td width="20%" align="right">�<a accesskey="n" href="DMSMig.html">Next</a></td></tr></table><hr></div><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="net2000users"></a>Chapter�6.�A Distributed 2000-User Network</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="sect1"><a href="net2000users.html#id2583726">Introduction</a></span></dt><dd><dl><dt><span class="sect2"><a href="net2000users.html#id2583756">Assignment Tasks</a></span></dt></dl></dd><dt><span class="sect1"><a href="net2000users.html#id2583824">Dissection and Discussion</a></span></dt><dd><dl><dt><span class="sect2"><a href="net2000users.html#id2584098">Technical Issues</a></span></dt><dt><span class="sect2"><a href="net2000users.html#id2585046">Political Issues</a></span></dt></dl></dd><dt><span class="sect1"><a href="net2000users.html#id2585064">Implementation</a></span></dt><dd><dl><dt><span class="sect2"><a href="net2000users.html#id2588223">Key Points Learned</a></span></dt></dl></dd><dt><span class="sect1"><a href="net2000users.html#id2588370">Questions and Answers</a></span></dt></dl></div><p> 2There is something indeed mystical about things that are 3big. Large networks exhibit a certain magnetism and exude a sense of 4importance that obscures reality. You and I know that it is no more 5difficult to secure a large network than it is a small one. We all 6know that over and above a particular number of network clients, the 7rules no longer change; the only real dynamic is the size of the domain 8(much like a kingdom) over which the network ruler (oops, administrator) 9has control. The real dynamic then transforms from the technical to the 10political. Then again, that point is often reached well before the 11kingdom (or queendom) grows large. 12</p><p> 13If you have systematically worked your way to this chapter, hopefully you 14have found some gems and techniques that are applicable in your 15world. The network designs you have worked with in this book have their 16strong points as well as weak ones. That is to be expected given that 17they are based on real business environments, the specifics of which are 18molded to serve the purposes of this book. 19</p><p> 20This chapter is intent on wrapping up issues that are central to 21implementation and design of progressively larger networks. Are you ready 22for this chapter? Good, it is time to move on. 23</p><p> 24In previous chapters, you made the assumption that your network 25administration staff need detailed instruction right down to the 26nuts and bolts of implementing the solution. That is still the case, 27but they have graduated now. You decide to document only those issues, 28methods, and techniques that are new or complex. Routine tasks such as 29implementing a DNS or a DHCP server are under control. Even the basics of 30Samba are largely under control. So in this section you focus on the 31specifics of implementing LDAP changes, Samba changes, and approach and 32design of the solution and its deployment. 33</p><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2583726"></a>Introduction</h2></div></div></div><p> 34Abmas is a miracle company. Most businesses would have collapsed under 35the weight of rapid expansion that this company has experienced. Samba 36is flexible, so there is no need to reinstall the whole operating 37system just because you need to implement a new network design. In fact, 38you can keep an old server running right up to the moment of cutover 39and then do a near-live conversion. There is no need to reinstall a 40Samba server just to change the way your network should function. 41</p><p> 42<a class="indexterm" name="id2583745"></a> 43Network growth is common to all organizations. In this exercise, 44your preoccupation is with the mechanics of implementing Samba and 45LDAP so that network users on each network segment can work 46without impediment. 47</p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2583756"></a>Assignment Tasks</h3></div></div></div><p> 48 Starting with the configuration files for the server called 49 <code class="constant">MASSIVE</code> in <a class="link" href="happy.html" title="Chapter�5.�Making Happy Users">“Making Happy Users”</a>, you now deal with the 50 issues that are particular to large distributed networks. Your task 51 is simple identify the challenges, consider the 52 alternatives, and then design and implement a solution. 53 </p><p> 54 <a class="indexterm" name="id2583784"></a> 55 Remember, you have users based in London (UK), Los Angeles, 56 Washington. DC, and, three buildings in New York. A significant portion 57 of your workforce have notebook computers and roam all over the 58 world. Some dial into the office, others use VPN connections over the 59 Internet, and others just move between buildings.i 60 </p><p> 61 What do you say to an employee who normally uses a desktop 62 system but must spend six weeks on the road with a notebook computer? 63 She is concerned about email access and how to keep coworkers current 64 with changing documents. 65 </p><p> 66 To top it all off, you have one network support person and one 67 help desk person based in London, a single person dedicated to all 68 network operations in Los Angeles, five staff for user administration 69 and help desk in New York, plus one <span class="emphasis"><em>floater</em></span> for 70 Washington. 71 </p><p> 72 You have outsourced all desktop deployment and management to 73 DirectPointe. Your concern is server maintenance and third-level 74 support. Build a plan and show what must be done. 75 </p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2583824"></a>Dissection and Discussion</h2></div></div></div><p> 76<a class="indexterm" name="id2583832"></a> 77<a class="indexterm" name="id2583839"></a> 78In <a class="link" href="happy.html" title="Chapter�5.�Making Happy Users">“Making Happy Users”</a>, you implemented an LDAP server that provided the 79<em class="parameter"><code>passdb backend</code></em> for the Samba servers. You 80explored ways to accelerate Windows desktop profile handling and you 81took control of network performance. 82</p><p> 83<a class="indexterm" name="id2583864"></a> 84<a class="indexterm" name="id2583871"></a> 85<a class="indexterm" name="id2583878"></a> 86<a class="indexterm" name="id2583884"></a> 87The implementation of an LDAP-based passdb backend (known as 88<span class="emphasis"><em>ldapsam</em></span> in Samba parlance), or some form of database 89that can be distributed, is essential to permit the deployment of Samba 90Primary and Backup Domain Controllers (PDC/BDCs). You see, the problem 91is that the <span class="emphasis"><em>tdbsam</em></span>-style passdb backend does not 92lend itself to being replicated. The older plain-text-based 93<span class="emphasis"><em>smbpasswd</em></span>-style passdb backend can be replicated 94using a tool such as <code class="literal">rsync</code>, but 95<span class="emphasis"><em>smbpasswd</em></span> suffers the drawback that it does not 96support the range of account facilities demanded by modern network 97managers. 98</p><p> 99<a class="indexterm" name="id2583924"></a> 100<a class="indexterm" name="id2583931"></a> 101The new <span class="emphasis"><em>tdbsam</em></span> facility supports functionality 102that is similar to an <span class="emphasis"><em>ldapsam</em></span>, but the lack of 103distributed infrastructure sorely limits the scope for its 104deployment. This raises the following questions: Why can't I just use 105an XML-based backend, or for that matter, why not use an SQL-based 106backend? Is support for these tools broken? Answers to these 107questions require a bit of background.</p><p> 108<a class="indexterm" name="id2583954"></a> 109<a class="indexterm" name="id2583961"></a> 110<a class="indexterm" name="id2583968"></a> 111<a class="indexterm" name="id2583975"></a> 112<span class="emphasis"><em>What is a directory?</em></span> A directory is a 113collection of information regarding objects that can be accessed to 114rapidly find information that is relevant in a particular and 115consistent manner. A directory differs from a database in that it is 116generally more often searched (read) than updated. As a consequence, the 117information is organized to facilitate read access rather than to 118support transaction processing.</p><p> 119<a class="indexterm" name="id2583995"></a> 120<a class="indexterm" name="id2584005"></a> 121<a class="indexterm" name="id2584012"></a> 122<a class="indexterm" name="id2584019"></a> 123The Lightweight Directory Access Protocol (LDAP) differs 124considerably from a traditional database. It has a simple search 125facility that uniquely makes a highly preferred mechanism for managing 126user identities. LDAP provides a scalable mechanism for distributing 127the data repository and for keeping all copies (slaves) in sync with 128the master repository.</p><p> 129<a class="indexterm" name="id2584035"></a> 130<a class="indexterm" name="id2584042"></a> 131<a class="indexterm" name="id2584049"></a> 132Samba is a flexible and powerful file and print sharing 133technology. It can use many external authentication sources and can be 134part of a total authentication and identity management 135infrastructure. The two most important external sources for large sites 136are Microsoft Active Directory and LDAP. Sites that specifically wish to 137avoid the proprietary implications of Microsoft Active Directory 138naturally gravitate toward OpenLDAP.</p><p> 139<a class="indexterm" name="id2584066"></a> 140In <a class="link" href="happy.html" title="Chapter�5.�Making Happy Users">“Making Happy Users”</a>, you had to deal with a locally routed 141network. All deployment concerns focused around making users happy, 142and that simply means taking control over all network practices and 143usage so that no one user is disadvantaged by any other. The real 144lesson is one of understanding that no matter how much network 145bandwidth you provide, bandwidth remains a precious resource.</p><p>In this chapter, you must now consider how the overall network must 146function. In particular, you must be concerned with users who move 147between offices. You must take into account the way users need to 148access information globally. And you must make the network robust 149enough so that it can sustain partial breakdown without causing loss of 150productivity.</p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2584098"></a>Technical Issues</h3></div></div></div><p> 151 There are at least three areas that need to be addressed as you 152 approach the challenge of designing a network solution for the newly 153 expanded business: 154 </p><div class="itemizedlist"><ul type="disc"><li><p><a class="indexterm" name="id2584114"></a> 155 User needs such as mobility and data access</p></li><li><p>The nature of Windows networking protocols</p></li><li><p>Identity management infrastructure needs</p></li></ul></div><p>Let's look at each in turn.</p><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2584137"></a>User Needs</h4></div></div></div><p> 156 The new company has three divisions. Staff for each division are spread across 157 the company. Some staff are office-bound and some are mobile users. Mobile 158 users travel globally. Some spend considerable periods working in other offices. 159 Everyone wants to be able to work without constraint of productivity. 160 </p><p> 161 The challenge is not insignificant. In some parts of the world, even dial-up 162 connectivity is poor, while in other regions political encumbrances severely 163 curtail user needs. Parts of the global Internet infrastructure remain shielded 164 off for reasons outside the scope of this discussion. 165 </p><p> 166 <a class="indexterm" name="id2584162"></a> 167 Decisions must be made regarding where data is to be stored, how it will be 168 replicated (if at all), and what the network bandwidth implications are. For 169 example, one decision that can be made is to give each office its own master 170 file storage area that can be synchronized to a central repository in New 171 York. This would permit global data to be backed up from a single location. 172 The synchronization tool could be <code class="literal">rsync,</code> run via a cron 173 job. Mobile users may use off-line file storage under Windows XP Professional. 174 This way, they can synchronize all files that have changed since each logon 175 to the network. 176 </p><p> 177 <a class="indexterm" name="id2584188"></a> 178 <a class="indexterm" name="id2584198"></a> 179 No matter which way you look at this, the bandwidth requirements 180 for acceptable performance are substantial even if only 10 percent of 181 staff are global data users. A company with 3,500 employees, 182 280 of whom are mobile users who use a similarly distributed 183 network, found they needed at least 2 Mb/sec connectivity 184 between the UK and US offices. Even over 2 Mb/sec bandwidth, this 185 company abandoned any attempt to run roaming profile usage for 186 mobile users. At that time, the average roaming profile took 480 187 KB, while today the minimum Windows XP Professional roaming 188 profile involves a transfer of over 750 KB from the profile 189 server to and from the client. 190 </p><p> 191 <a class="indexterm" name="id2584219"></a> 192 Obviously then, user needs and wide-area practicalities dictate the economic and 193 technical aspects of your network design as well as for standard operating procedures. 194 </p></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2584231"></a>The Nature of Windows Networking Protocols</h4></div></div></div><p> 195 <a class="indexterm" name="id2584239"></a> 196 Network logons that include roaming profile handling requires from 140 KB to 2 MB. 197 The inclusion of support for a minimal set of common desktop applications can push 198 the size of a complete profile to over 15 MB. This has substantial implications 199 for location of user profiles. Additionally, it is a significant factor in 200 determining the nature and style of mandatory profiles that may be enforced as 201 part of a total service-level assurance program that might be implemented. 202 </p><p> 203 <a class="indexterm" name="id2584260"></a> 204 <a class="indexterm" name="id2584267"></a> 205 One way to reduce the network bandwidth impact of user logon 206 traffic is through folder redirection. In <a class="link" href="happy.html" title="Chapter�5.�Making Happy Users">“Making Happy Users”</a>, you 207 implemented this in the new Windows XP Professional standard 208 desktop configuration. When desktop folders such as <span class="guimenu">My 209 Documents</span> are redirected to a network drive, they should 210 also be excluded from synchronization to and from the server on 211 logon or logout. Redirected folders are analogous to network drive 212 connections. 213 </p><p><a class="indexterm" name="id2584294"></a> 214 Of course, network applications should only be run off 215 local application servers. As a general rule, even with 2 Mb/sec 216 network bandwidth, it would not make sense at all for someone who 217 is working out of the London office to run applications off a 218 server that is located in New York. 219 </p><p> 220 <a class="indexterm" name="id2584310"></a> 221 When network bandwidth becomes a precious commodity (that is most 222 of the time), there is a significant demand to understand network 223 processes and to mold the limits of acceptability around the 224 constraints of affordability. 225 </p><p> 226 When a Windows NT4/200x/XP Professional client user logs onto 227 the network, several important things must happen. 228 </p><div class="itemizedlist"><ul type="disc"><li><p> 229 <a class="indexterm" name="id2584332"></a> 230 The client obtains an IP address via DHCP. (DHCP is 231 necessary so that users can roam between offices.) 232 </p></li><li><p> 233 <a class="indexterm" name="id2584345"></a> 234 <a class="indexterm" name="id2584352"></a> 235 The client must register itself with the WINS and/or DNS server. 236 </p></li><li><p> 237 <a class="indexterm" name="id2584364"></a> 238 The client must locate the closest domain controller. 239 </p></li><li><p> 240 The client must log onto a domain controller and obtain as part of 241 that process the location of the user's profile, load it, connect to 242 redirected folders, and establish all network drive and printer connections. 243 </p></li><li><p> 244 The domain controller must be able to resolve the user's 245 credentials before the logon process is fully implemented. 246 </p></li></ul></div><p> 247 Given that this book is about Samba and that it implements the Windows 248 NT4-style domain semantics, it makes little sense to compare Samba with 249 Microsoft Active Directory insofar as the logon protocols and principles 250 of operation are concerned. The following information pertains exclusively 251 to the interaction between a Windows XP Professional workstation and a 252 Samba-3.0.20 server. In the discussion that follows, use is made of DHCP and WINS. 253 </p><p> 254 As soon as the Windows workstation starts up, it obtains an 255 IP address. This is immediately followed by registration of its 256 name both by broadcast and Unicast registration that is directed 257 at the WINS server. 258 </p><p> 259 <a class="indexterm" name="id2584411"></a> 260 <a class="indexterm" name="id2584418"></a><a class="indexterm" name="id2584427"></a> 261 Given that the client is already a domain member, it then sends 262 a directed (Unicast) request to the WINS server seeking the list of 263 IP addresses for domain controllers (NetBIOS name type 0x1C). The 264 WINS server replies with the information requested.</p><p> 265 <a class="indexterm" name="id2584442"></a> 266 <a class="indexterm" name="id2584451"></a> 267 <a class="indexterm" name="id2584458"></a> 268 The client sends two netlogon mailslot broadcast requests 269 to the local network and to each of the IP addresses returned by 270 the WINS server. Whichever answers this request first appears to 271 be the machine that the Windows XP client attempts to use to 272 process the network logon. The mailslot messages use UDP broadcast 273 to the local network and UDP Unicast directed at each machine that 274 was listed in the WINS server response to a request for the list of 275 domain controllers. 276 </p><p> 277 <a class="indexterm" name="id2584476"></a> 278 <a class="indexterm" name="id2584485"></a> 279 <a class="indexterm" name="id2584492"></a> 280 The logon process begins with negotiation of the SMB/CIFS 281 protocols that are to be used; this is followed by an exchange of 282 information that ultimately includes the client sending the 283 credentials with which the user is attempting to logon. The logon 284 server must now approve the further establishment of the 285 connection, but that is a good point to halt for now. The priority 286 here must center around identification of network infrastructure 287 needs. A secondary fact we need to know is, what happens when 288 local domain controllers fail or break? 289 </p><p> 290 <a class="indexterm" name="id2584511"></a> 291 <a class="indexterm" name="id2584518"></a> 292 <a class="indexterm" name="id2584525"></a> 293 <a class="indexterm" name="id2584531"></a> 294 Under most circumstances, the nearest domain controller 295 responds to the netlogon mailslot broadcast. The exception to this 296 norm occurs when the nearest domain controller is too busy or is out 297 of service. Herein lies an important fact. This means it is 298 important that every network segment should have at least two 299 domain controllers. Since there can be only one PDC, all additional 300 domain controllers are by definition BDCs. 301 </p><p> 302 <a class="indexterm" name="id2584549"></a> 303 <a class="indexterm" name="id2584556"></a> 304 The provision of sufficient servers that are BDCs is an 305 important design factor. The second important design factor 306 involves how each of the BDCs obtains user authentication 307 data. That is the subject of the next section, which involves key 308 decisions regarding Identity Management facilities. 309 </p></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2584570"></a>Identity Management Needs</h4></div></div></div><p> 310 <a class="indexterm" name="id2584578"></a> 311 <a class="indexterm" name="id2584584"></a> 312 <a class="indexterm" name="id2584591"></a> 313 <a class="indexterm" name="id2584598"></a> 314 Network managers recognize that in large organizations users 315 generally need to be given resource access based on needs, while 316 being excluded from other resources for reasons of privacy. It is 317 therefore essential that all users identify themselves at the 318 point of network access. The network logon is the principal means 319 by which user credentials are validated and filtered and appropriate 320 rights and privileges are allocated. 321 </p><p> 322 <a class="indexterm" name="id2584616"></a> 323 <a class="indexterm" name="id2584622"></a> 324 <a class="indexterm" name="id2584629"></a> 325 Unfortunately, network resources tend to have their own Identity 326 Management facilities, the quality and manageability of which varies 327 from quite poor to exceptionally good. Corporations that use a mixture 328 of systems soon discover that until recently, few systems were 329 designed to interoperate. For example, UNIX systems each have an 330 independent user database. Sun Microsystems developed a facility that 331 was originally called <code class="constant">Yellow Pages</code>, and was renamed 332 when a telephone company objected to the use of its trademark. 333 What was once called <code class="constant">Yellow Pages</code> is today known 334 as <code class="constant">Network Information System</code> (NIS). 335 </p><p> 336 <a class="indexterm" name="id2584660"></a> 337 NIS gained a strong following throughout the UNIX/VMS space in a short 338 period of time and retained that appeal and use for over a decade. 339 Security concerns and inherent limitations have caused it to enter its 340 twilight. NIS did not gain widespread appeal outside of the UNIX world 341 and was not universally adopted. Sun updated this to a more secure 342 implementation called NIS+, but even it has fallen victim to changing 343 demands as the demand for directory services that can be coupled with 344 other information systems is catching on. 345 </p><p> 346 <a class="indexterm" name="id2584679"></a> 347 <a class="indexterm" name="id2584686"></a> 348 <a class="indexterm" name="id2584693"></a> 349 Nevertheless, both NIS and NIS+ continue to hold ground in 350 business areas where UNIX still has major sway. Examples of 351 organizations that remain firmly attached to the use of NIS and 352 NIS+ include large government departments, education institutions, 353 and large corporations that have a scientific or engineering 354 focus. 355 </p><p> 356 <a class="indexterm" name="id2584708"></a> 357 <a class="indexterm" name="id2584715"></a> 358 Today's networking world needs a scalable, distributed Identity 359 Management infrastructure, commonly called a directory. The most 360 popular technologies today are Microsoft Active Directory service 361 and a number of LDAP implementations. 362 </p><p> 363 <a class="indexterm" name="id2584729"></a> 364 The problem of managing multiple directories has become a focal 365 point over the past decade, creating a large market for 366 metadirectory products and services that allow organizations that 367 have multiple directories and multiple management and control 368 centers to provision information from one directory into 369 another. The attendant benefit to end users is the promise of 370 having to remember and deal with fewer login identities and 371 passwords.</p><p> 372 <a class="indexterm" name="id2584747"></a> 373 The challenge of every large network is to find the optimum 374 balance of internal systems and facilities for Identity 375 Management resources. How well the solution is chosen and 376 implemented has potentially significant impact on network bandwidth 377 and systems response needs.</p><p> 378 <a class="indexterm" name="id2584764"></a> 379 <a class="indexterm" name="id2584771"></a> 380 <a class="indexterm" name="id2584780"></a> 381 In <a class="link" href="happy.html" title="Chapter�5.�Making Happy Users">“Making Happy Users”</a>, you implemented a single LDAP server for the 382 entire network. This may work for smaller networks, but almost 383 certainly fails to meet the needs of large and complex networks. The 384 following section documents how you may implement a single 385 master LDAP server with multiple slave servers.</p><p> 386 What is the best method for implementing master/slave LDAP 387 servers within the context of a distributed 2,000-user network is a 388 question that remains to be answered.</p><p> 389 <a class="indexterm" name="id2584809"></a> 390 <a class="indexterm" name="id2584816"></a> 391 One possibility that has great appeal is to create a single, 392 large distributed domain. The practical implications of this 393 design (see <a class="link" href="net2000users.html#chap7net" title="Figure�6.6.�Network Topology 2000 User Complex Design A">“Network Topology 2000 User Complex Design A”</a>) demands the placement of 394 sufficient BDCs in each location. Additionally, network 395 administrators must make sure that profiles are not transferred 396 over the wide-area links, except as a totally unavoidable 397 measure. Network design must balance the risk of loss of user 398 productivity against the cost of network management and 399 maintenance. 400 </p><p> 401 <a class="indexterm" name="id2584847"></a> 402 The network design in <a class="link" href="net2000users.html#chap7net2" title="Figure�6.7.�Network Topology 2000 User Complex Design B">“Network Topology 2000 User Complex Design B”</a> takes the approach 403 that management of networks that are too remote to be managed 404 effectively from New York ought to be given a certain degree of 405 autonomy. With this rationale, the Los Angeles and London networks, 406 though fully integrated with those on the East Coast, each have their 407 own domain name space and can be independently managed and controlled. 408 One of the key drawbacks of this design is that it flies in the face of 409 the ability for network users to roam globally without some compromise 410 in how they may access global resources. 411 </p><p> 412 <a class="indexterm" name="id2584873"></a> 413 Desk-bound users need not be negatively affected by this design, since 414 the use of interdomain trusts can be used to satisfy the need for global 415 data sharing. 416 </p><p> 417 <a class="indexterm" name="id2584886"></a> 418 <a class="indexterm" name="id2584892"></a> 419 <a class="indexterm" name="id2584902"></a> 420 When Samba-3 is configured to use an LDAP backend, it stores the domain 421 account information in a directory entry. This account entry contains the 422 domain SID. An unintended but exploitable side effect is that this makes it 423 possible to operate with more than one PDC on a distributed network. 424 </p><p> 425 <a class="indexterm" name="id2584916"></a> 426 <a class="indexterm" name="id2584923"></a> 427 <a class="indexterm" name="id2584930"></a> 428 How might this peculiar feature be exploited? The answer is simple. It is 429 imperative that each network segment have its own WINS server. Major 430 servers on remote network segments can be given a static WINS entry in 431 the <code class="filename">wins.dat</code> file on each WINS server. This allows 432 all essential data to be visible from all locations. Each location would, 433 however, function as if it is an independent domain, while all sharing the 434 same domain SID. Since all domain account information can be stored in a 435 single LDAP backend, users have unfettered ability to roam. 436 </p><p> 437 <a class="indexterm" name="id2584955"></a> 438 <a class="indexterm" name="id2584964"></a> 439 This concept has not been exhaustively validated, though we can see no reason 440 why this should not work. The important facets are the following: The name of 441 the domain must be identical in all locations. Each network segment must have 442 its own WINS server. The name of the PDC must be the same in all locations; this 443 necessitates the use of NetBIOS name aliases for each PDC so that they can be 444 accessed globally using the alias and not the PDC's primary name. A single master 445 LDAP server can be based in New York, with multiple LDAP slave servers located 446 on every network segment. Finally, the BDCs should each use failover LDAP servers 447 that are in fact slave LDAP servers on the local segments. 448 </p><p> 449 <a class="indexterm" name="id2584986"></a> 450 <a class="indexterm" name="id2584995"></a> 451 <a class="indexterm" name="id2585002"></a> 452 <a class="indexterm" name="id2585011"></a> 453 With a single master LDAP server, all network updates are effected on a single 454 server. In the event that this should become excessively fragile or network 455 bandwidth limiting, one could implement a delegated LDAP domain. This is also 456 known as a partitioned (or multiple partition) LDAP database and as a distributed 457 LDAP directory. 458 </p><p> 459 As the LDAP directory grows, it becomes increasingly important 460 that its structure is implemented in a manner that mirrors 461 organizational needs, so as to limit network update and 462 referential traffic. It should be noted that all directory 463 administrators must of necessity follow the same standard 464 procedures for managing the directory, because retroactive correction of 465 inconsistent directory information can be exceedingly difficult. 466 </p></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2585046"></a>Political Issues</h3></div></div></div><p> 467 As organizations grow, the number of points of control increases 468 also. In a large distributed organization, it is important that the 469 Identity Management system be capable of being updated from 470 many locations, and it is equally important that changes made should 471 become usable in a reasonable period, typically 472 minutes rather than days (the old limitation of highly manual 473 systems). 474 </p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2585064"></a>Implementation</h2></div></div></div><p> 475 <a class="indexterm" name="id2585071"></a> 476 <a class="indexterm" name="id2585078"></a> 477 <a class="indexterm" name="id2585085"></a> 478 <a class="indexterm" name="id2585092"></a> 479 Samba-3 has the ability to use multiple password (authentication and 480 identity resolution) backends. The diagram in <a class="link" href="net2000users.html#chap7idres" title="Figure�6.1.�Samba and Authentication Backend Search Pathways">“Samba and Authentication Backend Search Pathways”</a> 481 demonstrates how Samba uses winbind, LDAP, and NIS, the traditional system 482 password database. The diagram only documents the mechanisms for 483 authentication and identity resolution (obtaining a UNIX UID/GID) 484 using the specific systems shown. 485 </p><div class="figure"><a name="chap7idres"></a><p class="title"><b>Figure�6.1.�Samba and Authentication Backend Search Pathways</b></p><div class="figure-contents"><div class="mediaobject"><img src="images/chap7-idresol.png" width="297" alt="Samba and Authentication Backend Search Pathways"></div></div></div><br class="figure-break"><p> 486 <a class="indexterm" name="id2585156"></a> 487 <a class="indexterm" name="id2585163"></a> 488 <a class="indexterm" name="id2585170"></a> 489 <a class="indexterm" name="id2585177"></a> 490 <a class="indexterm" name="id2585183"></a> 491 <a class="indexterm" name="id2585190"></a> 492 <a class="indexterm" name="id2585197"></a> 493 Samba is capable of using the <code class="constant">smbpasswd</code>, 494 <code class="constant">tdbsam</code>, <code class="constant">xmlsam</code>, 495 and <code class="constant">mysqlsam</code> authentication databases. The SMB 496 passwords can, of course, also be stored in an LDAP ldapsam 497 backend. LDAP is the preferred passdb backend for distributed network 498 operations. 499 </p><p> 500 <a class="indexterm" name="id2585225"></a> 501 Additionally, it is possible to use multiple passdb backends 502 concurrently as well as have multiple LDAP backends. As a result, you 503 can specify a failover LDAP backend. The syntax for specifying a 504 single LDAP backend in <code class="filename">smb.conf</code> is: 505</p><pre class="screen"> 506... 507passdb backend = ldapsam:ldap://master.abmas.biz 508... 509</pre><p> 510 This configuration tells Samba to use a single LDAP server, as shown in <a class="link" href="net2000users.html#ch7singleLDAP" title="Figure�6.2.�Samba Configuration to Use a Single LDAP Server">“Samba Configuration to Use a Single LDAP Server”</a>. 511 </p><div class="figure"><a name="ch7singleLDAP"></a><p class="title"><b>Figure�6.2.�Samba Configuration to Use a Single LDAP Server</b></p><div class="figure-contents"><div class="mediaobject"><img src="images/ch7-singleLDAP.png" width="351" alt="Samba Configuration to Use a Single LDAP Server"></div></div></div><p><br class="figure-break"> 512 <a class="indexterm" name="id2585298"></a> 513 <a class="indexterm" name="id2585308"></a> 514 The addition of a failover LDAP server can simply be done by adding a 515 second entry for the failover server to the single <em class="parameter"><code>ldapsam</code></em> 516 entry, as shown here (note the particular use of the double quotes): 517</p><pre class="screen"> 518... 519passdb backend = ldapsam:"ldap://master.abmas.biz \ 520 ldap://slave.abmas.biz" 521... 522</pre><p> 523 This configuration tells Samba to use a master LDAP server, with failover to a slave server if necessary, 524 as shown in <a class="link" href="net2000users.html#ch7dualLDAP" title="Figure�6.3.�Samba Configuration to Use a Dual (Fail-over) LDAP Server">“Samba Configuration to Use a Dual (Fail-over) LDAP Server”</a>. 525 </p><div class="figure"><a name="ch7dualLDAP"></a><p class="title"><b>Figure�6.3.�Samba Configuration to Use a Dual (Fail-over) LDAP Server</b></p><div class="figure-contents"><div class="mediaobject"><img src="images/ch7-fail-overLDAP.png" width="351" alt="Samba Configuration to Use a Dual (Fail-over) LDAP Server"></div></div></div><p><br class="figure-break"> 526 </p><p> 527 Some folks have tried to implement this without the use of double quotes. This is the type of entry they 528 created: 529</p><pre class="screen"> 530... 531passdb backend = ldapsam:ldap://master.abmas.biz \ 532 ldapsam:ldap://slave.abmas.biz 533... 534</pre><p> 535 <a class="indexterm" name="id2585394"></a> 536 The effect of this style of entry is that Samba lists the users 537 that are in both LDAP databases. If both contain the same information, 538 it results in each record being shown twice. This is, of course, not the 539 solution desired for a failover implementation. The net effect of this 540 configuration is shown in <a class="link" href="net2000users.html#ch7dualadd" title="Figure�6.4.�Samba Configuration to Use Dual LDAP Databases - Broken - Do Not Use!">“Samba Configuration to Use Dual LDAP Databases - Broken - Do Not Use!”</a> 541 </p><div class="figure"><a name="ch7dualadd"></a><p class="title"><b>Figure�6.4.�Samba Configuration to Use Dual LDAP Databases - Broken - Do Not Use!</b></p><div class="figure-contents"><div class="mediaobject"><img src="images/ch7-dual-additive-LDAP.png" width="297" alt="Samba Configuration to Use Dual LDAP Databases - Broken - Do Not Use!"></div></div></div><br class="figure-break"><p> 542 If, however, each LDAP database contains unique information, this may 543 well be an advantageous way to effectively integrate multiple LDAP databases 544 into one seemingly contiguous directory. Only the first database will be updated. 545 An example of this configuration is shown in <a class="link" href="net2000users.html#ch7dualok" title="Figure�6.5.�Samba Configuration to Use Two LDAP Databases - The result is additive.">“Samba Configuration to Use Two LDAP Databases - The result is additive.”</a>. 546 </p><div class="figure"><a name="ch7dualok"></a><p class="title"><b>Figure�6.5.�Samba Configuration to Use Two LDAP Databases - The result is additive.</b></p><div class="figure-contents"><div class="mediaobject"><img src="images/ch7-dual-additive-LDAP-Ok.png" width="297" alt="Samba Configuration to Use Two LDAP Databases - The result is additive."></div></div></div><br class="figure-break"><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p> 547 When the use of ldapsam is specified twice, as shown here, it is imperative 548 that the two LDAP directories must be disjoint. If the entries are for a 549 master LDAP server as well as its own slave server, updates to the LDAP 550 database may end up being lost or corrupted. You may safely use multiple 551 LDAP backends only if both are entirely separate from each other. 552 </p></div><p> 553 It is assumed that the network you are working with follows in a 554 pattern similar to what was covered in <a class="link" href="happy.html" title="Chapter�5.�Making Happy Users">“Making Happy Users”</a>. The following steps 555 permit the operation of a master/slave OpenLDAP arrangement. 556 </p><div class="procedure"><a name="id2585536"></a><p class="title"><b>Procedure�6.1.�Implementation Steps for an LDAP Slave Server</b></p><ol type="1"><li><p> 557 <a class="indexterm" name="id2585548"></a> 558 <a class="indexterm" name="id2585555"></a> 559 Log onto the master LDAP server as <code class="constant">root</code>. 560 You are about to change the configuration of the LDAP server, so it 561 makes sense to temporarily halt it. Stop OpenLDAP from running on 562 SUSE Linux by executing: 563</p><pre class="screen"> 564<code class="prompt">root# </code> rcldap stop 565</pre><p> 566 On Red Hat Linux, you can do this by executing: 567</p><pre class="screen"> 568<code class="prompt">root# </code> service ldap stop 569</pre><p> 570 </p></li><li><p> 571 <a class="indexterm" name="id2585600"></a> 572 Edit the <code class="filename">/etc/openldap/slapd.conf</code> file so it 573 matches the content of <a class="link" href="net2000users.html#ch7-LDAP-master" title="Example�6.1.�LDAP Master Server Configuration File /etc/openldap/slapd.conf">“LDAP Master Server Configuration File /etc/openldap/slapd.conf”</a>. 574 </p></li><li><p> 575 Create a file called <code class="filename">admin-accts.ldif</code> with the following contents: 576</p><pre class="screen"> 577dn: cn=updateuser,dc=abmas,dc=biz 578objectClass: person 579cn: updateuser 580sn: updateuser 581userPassword: not24get 582 583dn: cn=sambaadmin,dc=abmas,dc=biz 584objectClass: person 585cn: sambaadmin 586sn: sambaadmin 587userPassword: buttercup 588</pre><p> 589 </p></li><li><p> 590 Add an account called “<span class="quote">updateuser</span>” to the master LDAP server as shown here: 591</p><pre class="screen"> 592<code class="prompt">root# </code> slapadd -v -l admin-accts.ldif 593</pre><p> 594 </p></li><li><p> 595 <a class="indexterm" name="id2585673"></a> 596 <a class="indexterm" name="id2585680"></a> 597 Change directory to a suitable place to dump the contents of the 598 LDAP server. The dump file (and LDIF file) is used to preload 599 the slave LDAP server database. You can dump the database by executing: 600</p><pre class="screen"> 601<code class="prompt">root# </code> slapcat -v -l LDAP-transfer-LDIF.txt 602</pre><p> 603 Each record is written to the file. 604 </p></li><li><p> 605 <a class="indexterm" name="id2585712"></a> 606 Copy the file <code class="filename">LDAP-transfer-LDIF.txt</code> to the intended 607 slave LDAP server. A good location could be in the directory 608 <code class="filename">/etc/openldap/preload</code>. 609 </p></li><li><p> 610 Log onto the slave LDAP server as <code class="constant">root</code>. You can 611 now configure this server so the <code class="filename">/etc/openldap/slapd.conf</code> 612 file matches the content of <a class="link" href="net2000users.html#ch7-LDAP-slave" title="Example�6.2.�LDAP Slave Configuration File /etc/openldap/slapd.conf">“LDAP Slave Configuration File /etc/openldap/slapd.conf”</a>. 613 </p></li><li><p> 614 Change directory to the location in which you stored the 615 <code class="filename">LDAP-transfer-LDIF.txt</code> file (<code class="filename">/etc/openldap/preload</code>). 616 While in this directory, execute: 617</p><pre class="screen"> 618<code class="prompt">root# </code> slapadd -v -l LDAP-transfer-LDIF.txt 619</pre><p> 620 If all goes well, the following output confirms that the data is being loaded 621 as intended: 622</p><pre class="screen"> 623added: "dc=abmas,dc=biz" (00000001) 624added: "cn=sambaadmin,dc=abmas,dc=biz" (00000002) 625added: "cn=updateuser,dc=abmas,dc=biz" (00000003) 626added: "ou=People,dc=abmas,dc=biz" (00000004) 627added: "ou=Groups,dc=abmas,dc=biz" (00000005) 628added: "ou=Computers,dc=abmas,dc=biz" (00000006) 629added: "uid=Administrator,ou=People,dc=abmas,dc=biz" (00000007) 630added: "uid=nobody,ou=People,dc=abmas,dc=biz" (00000008) 631added: "cn=Domain Admins,ou=Groups,dc=abmas,dc=biz" (00000009) 632added: "cn=Domain Users,ou=Groups,dc=abmas,dc=biz" (0000000a) 633added: "cn=Domain Guests,ou=Groups,dc=abmas,dc=biz" (0000000b) 634added: "uid=bobj,ou=People,dc=abmas,dc=biz" (0000000c) 635added: "sambaDomainName=MEGANET2,dc=abmas,dc=biz" (0000000d) 636added: "uid=stans,ou=People,dc=abmas,dc=biz" (0000000e) 637added: "uid=chrisr,ou=People,dc=abmas,dc=biz" (0000000f) 638added: "uid=maryv,ou=People,dc=abmas,dc=biz" (00000010) 639added: "cn=Accounts,ou=Groups,dc=abmas,dc=biz" (00000011) 640added: "cn=Finances,ou=Groups,dc=abmas,dc=biz" (00000012) 641added: "cn=PIOps,ou=Groups,dc=abmas,dc=biz" (00000013) 642</pre><p> 643 </p></li><li><p> 644 Now start the LDAP server and set it to run automatically on system reboot by executing: 645</p><pre class="screen"> 646<code class="prompt">root# </code> rcldap start 647<code class="prompt">root# </code> chkconfig ldap on 648</pre><p> 649 On Red Hat Linux, execute the following: 650</p><pre class="screen"> 651<code class="prompt">root# </code> service ldap start 652<code class="prompt">root# </code> chkconfig ldap on 653</pre><p> 654 </p></li><li><p> 655 <a class="indexterm" name="id2585885"></a> 656 <a class="indexterm" name="id2585892"></a> 657 <a class="indexterm" name="id2585899"></a> 658 Go back to the master LDAP server. Execute the following to start LDAP as well 659 as <code class="literal">slurpd</code>, the synchronization daemon, as shown here: 660</p><pre class="screen"> 661<code class="prompt">root# </code> rcldap start 662<code class="prompt">root# </code> chkconfig ldap on 663<code class="prompt">root# </code> rcslurpd start 664<code class="prompt">root# </code> chkconfig slurpd on 665</pre><p> 666 <a class="indexterm" name="id2585944"></a> 667 On Red Hat Linux, check the equivalent command to start <code class="literal">slurpd</code>. 668 </p></li><li><p> 669 <a class="indexterm" name="id2585965"></a> 670 On the master LDAP server you may now add an account to validate that replication 671 is working. Assuming the configuration shown in <a class="link" href="happy.html" title="Chapter�5.�Making Happy Users">“Making Happy Users”</a>, execute: 672</p><pre class="screen"> 673<code class="prompt">root# </code> /var/lib/samba/sbin/smbldap-useradd -a fruitloop 674</pre><p> 675 </p></li><li><p> 676 On the slave LDAP server, change to the directory <code class="filename">/var/lib/ldap</code>. 677 There should now be a file called <code class="filename">replogfile</code>. If replication worked 678 as expected, the content of this file should be: 679</p><pre class="screen"> 680time: 1072486403 681dn: uid=fruitloop,ou=People,dc=abmas,dc=biz 682changetype: modify 683replace: sambaProfilePath 684sambaProfilePath: \\MASSIVE\profiles\fruitloop 685- 686replace: sambaHomePath 687sambaHomePath: \\MASSIVE\homes 688- 689replace: entryCSN 690entryCSN: 2003122700:43:38Z#0x0005#0#0000 691- 692replace: modifiersName 693modifiersName: cn=Manager,dc=abmas,dc=biz 694- 695replace: modifyTimestamp 696modifyTimestamp: 20031227004338Z 697- 698</pre><p> 699 </p></li><li><p> 700 Given that this first slave LDAP server is now working correctly, you may now 701 implement additional slave LDAP servers as required. 702 </p></li><li><p> 703 On each machine (PDC and BDCs) after the respective <code class="filename">smb.conf</code> files have been created as shown in 704 <a class="link" href="net2000users.html#ch7-massmbconfA" title="Example�6.3.�Primary Domain Controller smb.conf File Part A">Primary Domain Controller <code class="filename">smb.conf</code> File Part A + B + C</a> and 705 on BDCs the <a class="link" href="net2000users.html#ch7-slvsmbocnfA" title="Example�6.6.�Backup Domain Controller smb.conf File Part A">Backup Domain Controller <code class="filename">smb.conf</code> File Part A 706 + B + C</a> execute the following: 707</p><pre class="screen"> 708<code class="prompt">root# </code> smbpasswd -w buttercup 709</pre><p> 710 This will install in the <code class="filename">secrets.tdb</code> file the password that Samba will need to 711 manage (write to) the LDAP Master server to perform account updates. 712 </p></li></ol></div><div class="example"><a name="ch7-LDAP-master"></a><p class="title"><b>Example�6.1.�LDAP Master Server Configuration File <code class="filename">/etc/openldap/slapd.conf</code></b></p><div class="example-contents"><pre class="screen"> 713include /etc/openldap/schema/core.schema 714include /etc/openldap/schema/cosine.schema 715include /etc/openldap/schema/inetorgperson.schema 716include /etc/openldap/schema/nis.schema 717include /etc/openldap/schema/samba.schema 718 719pidfile /var/run/slapd/slapd.pid 720argsfile /var/run/slapd/slapd.args 721 722database bdb 723suffix "dc=abmas,dc=biz" 724rootdn "cn=Manager,dc=abmas,dc=biz" 725 726# rootpw = not24get 727rootpw {SSHA}86kTavd9Dw3FAz6qzWTrCOKX/c0Qe+UV 728 729replica host=lapdc.abmas.biz:389 730 suffix="dc=abmas,dc=biz" 731 binddn="cn=updateuser,dc=abmas,dc=biz" 732 bindmethod=simple credentials=not24get 733 734access to attrs=sambaLMPassword,sambaNTPassword 735 by dn="cn=sambaadmin,dc=abmas,dc=biz" write 736 by * none 737 738replogfile /var/lib/ldap/replogfile 739 740directory /var/lib/ldap 741 742# Indices to maintain 743index objectClass eq 744index cn pres,sub,eq 745index sn pres,sub,eq 746index uid pres,sub,eq 747index displayName pres,sub,eq 748index uidNumber eq 749index gidNumber eq 750index memberUID eq 751index sambaSID eq 752index sambaPrimaryGroupSID eq 753index sambaDomainName eq 754index default sub 755</pre></div></div><br class="example-break"><div class="example"><a name="ch7-LDAP-slave"></a><p class="title"><b>Example�6.2.�LDAP Slave Configuration File <code class="filename">/etc/openldap/slapd.conf</code></b></p><div class="example-contents"><pre class="screen"> 756include /etc/openldap/schema/core.schema 757include /etc/openldap/schema/cosine.schema 758include /etc/openldap/schema/inetorgperson.schema 759include /etc/openldap/schema/nis.schema 760include /etc/openldap/schema/samba.schema 761 762pidfile /var/run/slapd/slapd.pid 763argsfile /var/run/slapd/slapd.args 764 765database bdb 766suffix "dc=abmas,dc=biz" 767rootdn "cn=Manager,dc=abmas,dc=biz" 768 769# rootpw = not24get 770rootpw {SSHA}86kTavd9Dw3FAz6qzWTrCOKX/c0Qe+UV 771 772access to * 773 by dn=cn=updateuser,dc=abmas,dc=biz write 774 by * read 775 776updatedn cn=updateuser,dc=abmas,dc=biz 777updateref ldap://massive.abmas.biz 778 779directory /var/lib/ldap 780 781# Indices to maintain 782index objectClass eq 783index cn pres,sub,eq 784index sn pres,sub,eq 785index uid pres,sub,eq 786index displayName pres,sub,eq 787index uidNumber eq 788index gidNumber eq 789index memberUID eq 790index sambaSID eq 791index sambaPrimaryGroupSID eq 792index sambaDomainName eq 793index default sub 794</pre></div></div><br class="example-break"><div class="example"><a name="ch7-massmbconfA"></a><p class="title"><b>Example�6.3.�Primary Domain Controller <code class="filename">smb.conf</code> File Part A</b></p><div class="example-contents"><table class="simplelist" border="0" summary="Simple list"><tr><td># Global parameters</td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[global]</code></em></td></tr><tr><td><a class="indexterm" name="id2586228"></a><em class="parameter"><code>unix charset = LOCALE</code></em></td></tr><tr><td><a class="indexterm" name="id2586240"></a><em class="parameter"><code>workgroup = MEGANET2</code></em></td></tr><tr><td><a class="indexterm" name="id2586252"></a><em class="parameter"><code>passdb backend = ldapsam:ldap://massive.abmas.biz</code></em></td></tr><tr><td><a class="indexterm" name="id2586264"></a><em class="parameter"><code>username map = /etc/samba/smbusers</code></em></td></tr><tr><td><a class="indexterm" name="id2586276"></a><em class="parameter"><code>log level = 1</code></em></td></tr><tr><td><a class="indexterm" name="id2586288"></a><em class="parameter"><code>syslog = 0</code></em></td></tr><tr><td><a class="indexterm" name="id2586299"></a><em class="parameter"><code>log file = /var/log/samba/%m</code></em></td></tr><tr><td><a class="indexterm" name="id2586311"></a><em class="parameter"><code>max log size = 0</code></em></td></tr><tr><td><a class="indexterm" name="id2586323"></a><em class="parameter"><code>smb ports = 139</code></em></td></tr><tr><td><a class="indexterm" name="id2586335"></a><em class="parameter"><code>name resolve order = wins bcast hosts</code></em></td></tr><tr><td><a class="indexterm" name="id2586347"></a><em class="parameter"><code>time server = Yes</code></em></td></tr><tr><td><a class="indexterm" name="id2586358"></a><em class="parameter"><code>printcap name = CUPS</code></em></td></tr><tr><td><a class="indexterm" name="id2586370"></a><em class="parameter"><code>add user script = /opt/IDEALX/sbin/smbldap-useradd -m '%u'</code></em></td></tr><tr><td><a class="indexterm" name="id2586383"></a><em class="parameter"><code>delete user script = /opt/IDEALX/sbin/smbldap-userdel '%u'</code></em></td></tr><tr><td><a class="indexterm" name="id2586395"></a><em class="parameter"><code>add group script = /opt/IDEALX/sbin/smbldap-groupadd -p '%g'</code></em></td></tr><tr><td><a class="indexterm" name="id2586408"></a><em class="parameter"><code>delete group script = /opt/IDEALX/sbin/smbldap-groupdel '%g'</code></em></td></tr><tr><td><a class="indexterm" name="id2586420"></a><em class="parameter"><code>add user to group script = /opt/IDEALX/sbin/smbldap-groupmod -m '%g' '%u'</code></em></td></tr><tr><td><a class="indexterm" name="id2586433"></a><em class="parameter"><code>delete user from group script = /opt/IDEALX/sbin/smbldap-groupmod -x '%g' '%u'</code></em></td></tr><tr><td><a class="indexterm" name="id2586446"></a><em class="parameter"><code>set primary group script = /opt/IDEALX/sbin/smbldap-usermod -g '%g' '%u'</code></em></td></tr><tr><td><a class="indexterm" name="id2586459"></a><em class="parameter"><code>add machine script = /opt/IDEALX/sbin/smbldap-useradd -w '%u'</code></em></td></tr><tr><td><a class="indexterm" name="id2586471"></a><em class="parameter"><code>shutdown script = /var/lib/samba/scripts/shutdown.sh</code></em></td></tr><tr><td><a class="indexterm" name="id2586484"></a><em class="parameter"><code>abort shutdown script = /sbin/shutdown -c</code></em></td></tr><tr><td><a class="indexterm" name="id2586496"></a><em class="parameter"><code>logon script = scripts\logon.bat</code></em></td></tr><tr><td><a class="indexterm" name="id2586508"></a><em class="parameter"><code>logon path = \\%L\profiles\%U</code></em></td></tr><tr><td><a class="indexterm" name="id2586520"></a><em class="parameter"><code>logon drive = X:</code></em></td></tr><tr><td><a class="indexterm" name="id2586531"></a><em class="parameter"><code>domain logons = Yes</code></em></td></tr><tr><td><a class="indexterm" name="id2586543"></a><em class="parameter"><code>domain master = Yes</code></em></td></tr><tr><td><a class="indexterm" name="id2586555"></a><em class="parameter"><code>wins support = Yes</code></em></td></tr><tr><td><a class="indexterm" name="id2586567"></a><em class="parameter"><code>ldap suffix = dc=abmas,dc=biz</code></em></td></tr><tr><td><a class="indexterm" name="id2586578"></a><em class="parameter"><code>ldap machine suffix = ou=People</code></em></td></tr><tr><td><a class="indexterm" name="id2586590"></a><em class="parameter"><code>ldap user suffix = ou=People</code></em></td></tr><tr><td><a class="indexterm" name="id2586602"></a><em class="parameter"><code>ldap group suffix = ou=Groups</code></em></td></tr><tr><td><a class="indexterm" name="id2586614"></a><em class="parameter"><code>ldap idmap suffix = ou=Idmap</code></em></td></tr><tr><td><a class="indexterm" name="id2586626"></a><em class="parameter"><code>ldap admin dn = cn=sambaadmin,dc=abmas,dc=biz</code></em></td></tr><tr><td><a class="indexterm" name="id2586639"></a><em class="parameter"><code>idmap backend = ldap://massive.abmas.biz</code></em></td></tr><tr><td><a class="indexterm" name="id2586651"></a><em class="parameter"><code>idmap uid = 10000-20000</code></em></td></tr><tr><td><a class="indexterm" name="id2586663"></a><em class="parameter"><code>idmap gid = 10000-20000</code></em></td></tr><tr><td><a class="indexterm" name="id2586674"></a><em class="parameter"><code>printer admin = root</code></em></td></tr><tr><td><a class="indexterm" name="id2586686"></a><em class="parameter"><code>printing = cups</code></em></td></tr></table></div></div><br class="example-break"><div class="example"><a name="ch7-massmbconfB"></a><p class="title"><b>Example�6.4.�Primary Domain Controller <code class="filename">smb.conf</code> File Part B</b></p><div class="example-contents"><table class="simplelist" border="0" summary="Simple list"><tr><td> </td></tr><tr><td><em class="parameter"><code>[IPC$]</code></em></td></tr><tr><td><a class="indexterm" name="id2586732"></a><em class="parameter"><code>path = /tmp</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[accounts]</code></em></td></tr><tr><td><a class="indexterm" name="id2586752"></a><em class="parameter"><code>comment = Accounting Files</code></em></td></tr><tr><td><a class="indexterm" name="id2586764"></a><em class="parameter"><code>path = /data/accounts</code></em></td></tr><tr><td><a class="indexterm" name="id2586776"></a><em class="parameter"><code>read only = No</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[service]</code></em></td></tr><tr><td><a class="indexterm" name="id2586796"></a><em class="parameter"><code>comment = Financial Services Files</code></em></td></tr><tr><td><a class="indexterm" name="id2586808"></a><em class="parameter"><code>path = /data/service</code></em></td></tr><tr><td><a class="indexterm" name="id2586820"></a><em class="parameter"><code>read only = No</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[pidata]</code></em></td></tr><tr><td><a class="indexterm" name="id2586840"></a><em class="parameter"><code>comment = Property Insurance Files</code></em></td></tr><tr><td><a class="indexterm" name="id2586852"></a><em class="parameter"><code>path = /data/pidata</code></em></td></tr><tr><td><a class="indexterm" name="id2586864"></a><em class="parameter"><code>read only = No</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[homes]</code></em></td></tr><tr><td><a class="indexterm" name="id2586884"></a><em class="parameter"><code>comment = Home Directories</code></em></td></tr><tr><td><a class="indexterm" name="id2586896"></a><em class="parameter"><code>valid users = %S</code></em></td></tr><tr><td><a class="indexterm" name="id2586908"></a><em class="parameter"><code>read only = No</code></em></td></tr><tr><td><a class="indexterm" name="id2586919"></a><em class="parameter"><code>browseable = No</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[printers]</code></em></td></tr><tr><td><a class="indexterm" name="id2586940"></a><em class="parameter"><code>comment = SMB Print Spool</code></em></td></tr><tr><td><a class="indexterm" name="id2586951"></a><em class="parameter"><code>path = /var/spool/samba</code></em></td></tr><tr><td><a class="indexterm" name="id2586963"></a><em class="parameter"><code>guest ok = Yes</code></em></td></tr><tr><td><a class="indexterm" name="id2586975"></a><em class="parameter"><code>printable = Yes</code></em></td></tr><tr><td><a class="indexterm" name="id2586986"></a><em class="parameter"><code>browseable = No</code></em></td></tr></table></div></div><br class="example-break"><div class="example"><a name="ch7-massmbconfC"></a><p class="title"><b>Example�6.5.�Primary Domain Controller <code class="filename">smb.conf</code> File Part C</b></p><div class="example-contents"><table class="simplelist" border="0" summary="Simple list"><tr><td> </td></tr><tr><td><em class="parameter"><code>[apps]</code></em></td></tr><tr><td><a class="indexterm" name="id2587032"></a><em class="parameter"><code>comment = Application Files</code></em></td></tr><tr><td><a class="indexterm" name="id2587044"></a><em class="parameter"><code>path = /apps</code></em></td></tr><tr><td><a class="indexterm" name="id2587055"></a><em class="parameter"><code>admin users = bjones</code></em></td></tr><tr><td><a class="indexterm" name="id2587067"></a><em class="parameter"><code>read only = No</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[netlogon]</code></em></td></tr><tr><td><a class="indexterm" name="id2587087"></a><em class="parameter"><code>comment = Network Logon Service</code></em></td></tr><tr><td><a class="indexterm" name="id2587099"></a><em class="parameter"><code>path = /var/lib/samba/netlogon</code></em></td></tr><tr><td><a class="indexterm" name="id2587111"></a><em class="parameter"><code>admin users = root, Administrator</code></em></td></tr><tr><td><a class="indexterm" name="id2587123"></a><em class="parameter"><code>guest ok = Yes</code></em></td></tr><tr><td><a class="indexterm" name="id2587135"></a><em class="parameter"><code>locking = No</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[profiles]</code></em></td></tr><tr><td><a class="indexterm" name="id2587155"></a><em class="parameter"><code>comment = Profile Share</code></em></td></tr><tr><td><a class="indexterm" name="id2587167"></a><em class="parameter"><code>path = /var/lib/samba/profiles</code></em></td></tr><tr><td><a class="indexterm" name="id2587179"></a><em class="parameter"><code>read only = No</code></em></td></tr><tr><td><a class="indexterm" name="id2587190"></a><em class="parameter"><code>profile acls = Yes</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[profdata]</code></em></td></tr><tr><td><a class="indexterm" name="id2587211"></a><em class="parameter"><code>comment = Profile Data Share</code></em></td></tr><tr><td><a class="indexterm" name="id2587223"></a><em class="parameter"><code>path = /var/lib/samba/profdata</code></em></td></tr><tr><td><a class="indexterm" name="id2587235"></a><em class="parameter"><code>read only = No</code></em></td></tr><tr><td><a class="indexterm" name="id2587246"></a><em class="parameter"><code>profile acls = Yes</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[print$]</code></em></td></tr><tr><td><a class="indexterm" name="id2587267"></a><em class="parameter"><code>comment = Printer Drivers</code></em></td></tr><tr><td><a class="indexterm" name="id2587279"></a><em class="parameter"><code>path = /var/lib/samba/drivers</code></em></td></tr><tr><td><a class="indexterm" name="id2587291"></a><em class="parameter"><code>write list = root</code></em></td></tr><tr><td><a class="indexterm" name="id2587302"></a><em class="parameter"><code>admin users = root, Administrator</code></em></td></tr></table></div></div><br class="example-break"><div class="example"><a name="ch7-slvsmbocnfA"></a><p class="title"><b>Example�6.6.�Backup Domain Controller <code class="filename">smb.conf</code> File Part A</b></p><div class="example-contents"><table class="simplelist" border="0" summary="Simple list"><tr><td># # Global parameters</td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[global]</code></em></td></tr><tr><td><a class="indexterm" name="id2587352"></a><em class="parameter"><code>unix charset = LOCALE</code></em></td></tr><tr><td><a class="indexterm" name="id2587363"></a><em class="parameter"><code>workgroup = MEGANET2</code></em></td></tr><tr><td><a class="indexterm" name="id2587375"></a><em class="parameter"><code>netbios name = BLDG1</code></em></td></tr><tr><td><a class="indexterm" name="id2587387"></a><em class="parameter"><code>passdb backend = ldapsam:ldap://lapdc.abmas.biz</code></em></td></tr><tr><td><a class="indexterm" name="id2587399"></a><em class="parameter"><code>username map = /etc/samba/smbusers</code></em></td></tr><tr><td><a class="indexterm" name="id2587411"></a><em class="parameter"><code>log level = 1</code></em></td></tr><tr><td><a class="indexterm" name="id2587423"></a><em class="parameter"><code>syslog = 0</code></em></td></tr><tr><td><a class="indexterm" name="id2587434"></a><em class="parameter"><code>log file = /var/log/samba/%m</code></em></td></tr><tr><td><a class="indexterm" name="id2587446"></a><em class="parameter"><code>max log size = 50</code></em></td></tr><tr><td><a class="indexterm" name="id2587458"></a><em class="parameter"><code>smb ports = 139</code></em></td></tr><tr><td><a class="indexterm" name="id2587469"></a><em class="parameter"><code>name resolve order = wins bcast hosts</code></em></td></tr><tr><td><a class="indexterm" name="id2587481"></a><em class="parameter"><code>printcap name = CUPS</code></em></td></tr><tr><td><a class="indexterm" name="id2587493"></a><em class="parameter"><code>show add printer wizard = No</code></em></td></tr><tr><td><a class="indexterm" name="id2587505"></a><em class="parameter"><code>logon script = scripts\logon.bat</code></em></td></tr><tr><td><a class="indexterm" name="id2587517"></a><em class="parameter"><code>logon path = \\%L\profiles\%U</code></em></td></tr><tr><td><a class="indexterm" name="id2587529"></a><em class="parameter"><code>logon drive = X:</code></em></td></tr><tr><td><a class="indexterm" name="id2587541"></a><em class="parameter"><code>domain logons = Yes</code></em></td></tr><tr><td><a class="indexterm" name="id2587553"></a><em class="parameter"><code>os level = 63</code></em></td></tr><tr><td><a class="indexterm" name="id2587564"></a><em class="parameter"><code>domain master = No</code></em></td></tr><tr><td><a class="indexterm" name="id2587576"></a><em class="parameter"><code>wins server = 192.168.2.1</code></em></td></tr><tr><td><a class="indexterm" name="id2587588"></a><em class="parameter"><code>ldap suffix = dc=abmas,dc=biz</code></em></td></tr><tr><td><a class="indexterm" name="id2587600"></a><em class="parameter"><code>ldap machine suffix = ou=People</code></em></td></tr><tr><td><a class="indexterm" name="id2587612"></a><em class="parameter"><code>ldap user suffix = ou=People</code></em></td></tr><tr><td><a class="indexterm" name="id2587624"></a><em class="parameter"><code>ldap group suffix = ou=Groups</code></em></td></tr><tr><td><a class="indexterm" name="id2587636"></a><em class="parameter"><code>ldap idmap suffix = ou=Idmap</code></em></td></tr><tr><td><a class="indexterm" name="id2587648"></a><em class="parameter"><code>ldap admin dn = cn=sambaadmin,dc=abmas,dc=biz</code></em></td></tr><tr><td><a class="indexterm" name="id2587660"></a><em class="parameter"><code>utmp = Yes</code></em></td></tr><tr><td><a class="indexterm" name="id2587671"></a><em class="parameter"><code>idmap backend = ldap://massive.abmas.biz</code></em></td></tr><tr><td><a class="indexterm" name="id2587683"></a><em class="parameter"><code>idmap uid = 10000-20000</code></em></td></tr><tr><td><a class="indexterm" name="id2587695"></a><em class="parameter"><code>idmap gid = 10000-20000</code></em></td></tr><tr><td><a class="indexterm" name="id2587707"></a><em class="parameter"><code>printing = cups</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[accounts]</code></em></td></tr><tr><td><a class="indexterm" name="id2587727"></a><em class="parameter"><code>comment = Accounting Files</code></em></td></tr><tr><td><a class="indexterm" name="id2587739"></a><em class="parameter"><code>path = /data/accounts</code></em></td></tr><tr><td><a class="indexterm" name="id2587751"></a><em class="parameter"><code>read only = No</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[service]</code></em></td></tr><tr><td><a class="indexterm" name="id2587771"></a><em class="parameter"><code>comment = Financial Services Files</code></em></td></tr><tr><td><a class="indexterm" name="id2587783"></a><em class="parameter"><code>path = /data/service</code></em></td></tr><tr><td><a class="indexterm" name="id2587795"></a><em class="parameter"><code>read only = No</code></em></td></tr></table></div></div><br class="example-break"><div class="example"><a name="ch7-slvsmbocnfB"></a><p class="title"><b>Example�6.7.�Backup Domain Controller <code class="filename">smb.conf</code> File Part B</b></p><div class="example-contents"><table class="simplelist" border="0" summary="Simple list"><tr><td> </td></tr><tr><td><em class="parameter"><code>[pidata]</code></em></td></tr><tr><td><a class="indexterm" name="id2587841"></a><em class="parameter"><code>comment = Property Insurance Files</code></em></td></tr><tr><td><a class="indexterm" name="id2587853"></a><em class="parameter"><code>path = /data/pidata</code></em></td></tr><tr><td><a class="indexterm" name="id2587864"></a><em class="parameter"><code>read only = No</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[homes]</code></em></td></tr><tr><td><a class="indexterm" name="id2587884"></a><em class="parameter"><code>comment = Home Directories</code></em></td></tr><tr><td><a class="indexterm" name="id2587896"></a><em class="parameter"><code>valid users = %S</code></em></td></tr><tr><td><a class="indexterm" name="id2587908"></a><em class="parameter"><code>read only = No</code></em></td></tr><tr><td><a class="indexterm" name="id2587919"></a><em class="parameter"><code>browseable = No</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[printers]</code></em></td></tr><tr><td><a class="indexterm" name="id2587940"></a><em class="parameter"><code>comment = SMB Print Spool</code></em></td></tr><tr><td><a class="indexterm" name="id2587952"></a><em class="parameter"><code>path = /var/spool/samba</code></em></td></tr><tr><td><a class="indexterm" name="id2587963"></a><em class="parameter"><code>guest ok = Yes</code></em></td></tr><tr><td><a class="indexterm" name="id2587975"></a><em class="parameter"><code>printable = Yes</code></em></td></tr><tr><td><a class="indexterm" name="id2587987"></a><em class="parameter"><code>browseable = No</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[apps]</code></em></td></tr><tr><td><a class="indexterm" name="id2588007"></a><em class="parameter"><code>comment = Application Files</code></em></td></tr><tr><td><a class="indexterm" name="id2588019"></a><em class="parameter"><code>path = /apps</code></em></td></tr><tr><td><a class="indexterm" name="id2588030"></a><em class="parameter"><code>admin users = bjones</code></em></td></tr><tr><td><a class="indexterm" name="id2588042"></a><em class="parameter"><code>read only = No</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[netlogon]</code></em></td></tr><tr><td><a class="indexterm" name="id2588063"></a><em class="parameter"><code>comment = Network Logon Service</code></em></td></tr><tr><td><a class="indexterm" name="id2588075"></a><em class="parameter"><code>path = /var/lib/samba/netlogon</code></em></td></tr><tr><td><a class="indexterm" name="id2588086"></a><em class="parameter"><code>guest ok = Yes</code></em></td></tr><tr><td><a class="indexterm" name="id2588098"></a><em class="parameter"><code>locking = No</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[profiles]</code></em></td></tr><tr><td><a class="indexterm" name="id2588119"></a><em class="parameter"><code>comment = Profile Share</code></em></td></tr><tr><td><a class="indexterm" name="id2588130"></a><em class="parameter"><code>path = /var/lib/samba/profiles</code></em></td></tr><tr><td><a class="indexterm" name="id2588142"></a><em class="parameter"><code>read only = No</code></em></td></tr><tr><td><a class="indexterm" name="id2588154"></a><em class="parameter"><code>profile acls = Yes</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[profdata]</code></em></td></tr><tr><td><a class="indexterm" name="id2588174"></a><em class="parameter"><code>comment = Profile Data Share</code></em></td></tr><tr><td><a class="indexterm" name="id2588186"></a><em class="parameter"><code>path = /var/lib/samba/profdata</code></em></td></tr><tr><td><a class="indexterm" name="id2588198"></a><em class="parameter"><code>read only = No</code></em></td></tr><tr><td><a class="indexterm" name="id2588210"></a><em class="parameter"><code>profile acls = Yes</code></em></td></tr></table></div></div><br class="example-break"><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2588223"></a>Key Points Learned</h3></div></div></div><div class="itemizedlist"><ul type="disc"><li><p> 795 <a class="indexterm" name="id2588234"></a><a class="indexterm" name="id2588239"></a> 796 Where Samba-3 is used as a domain controller, the use of LDAP is an 797 essential component to permit the use of BDCs. 798 </p></li><li><p> 799 <a class="indexterm" name="id2588252"></a> 800 Replication of the LDAP master server to create a network of BDCs 801 is an important mechanism for limiting WAN traffic. 802 </p></li><li><p> 803 Network administration presents many complex challenges, most of which 804 can be satisfied by good design but that also require sound communication 805 and unification of management practices. This can be highly challenging in 806 a large, globally distributed network. 807 </p></li><li><p> 808 Roaming profiles must be contained to the local network segment. Any 809 departure from this may clog wide-area arteries and slow legitimate network 810 traffic to a crawl. 811 </p></li></ul></div></div><div class="figure"><a name="chap7net"></a><p class="title"><b>Figure�6.6.�Network Topology 2000 User Complex Design A</b></p><div class="figure-contents"><div class="mediaobject"><img src="images/chap7-net-Ar.png" width="432" alt="Network Topology 2000 User Complex Design A"></div></div></div><br class="figure-break"><div class="figure"><a name="chap7net2"></a><p class="title"><b>Figure�6.7.�Network Topology 2000 User Complex Design B</b></p><div class="figure-contents"><div class="mediaobject"><img src="images/chap7-net2-Br.png" width="432" alt="Network Topology 2000 User Complex Design B"></div></div></div><br class="figure-break"></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2588370"></a>Questions and Answers</h2></div></div></div><p> 812 There is much rumor and misinformation regarding the use of MS Windows networking protocols. 813 These questions are just a few of those frequently asked. 814 </p><div class="qandaset"><dl><dt> <a href="net2000users.html#id2588388"> 815 816 817 Is it true that DHCP uses lots of WAN bandwidth? 818 </a></dt><dt> <a href="net2000users.html#id2588523"> 819 820 821 How much background communication takes place between a master LDAP server and its slave LDAP servers? 822 </a></dt><dt> <a href="net2000users.html#id2588584"> 823 LDAP has a database. Is LDAP not just a fancy database front end? 824 </a></dt><dt> <a href="net2000users.html#id2588648"> 825 826 Can Active Directory obtain account information from an OpenLDAP server? 827 </a></dt><dt> <a href="net2000users.html#id2588683"> 828 What are the parts of a roaming profile? How large is each part? 829 </a></dt><dt> <a href="net2000users.html#id2588832"> 830 Can the My Documents folder be stored on a network drive? 831 </a></dt><dt> <a href="net2000users.html#id2588880"> 832 833 834 835 How much WAN bandwidth does WINS consume? 836 </a></dt><dt> <a href="net2000users.html#id2588964"> 837 How many BDCs should I have? What is the right number of Windows clients per server? 838 </a></dt><dt> <a href="net2000users.html#id2589000"> 839 840 I've heard that you can store NIS accounts in LDAP. Is LDAP not just a smarter way to 841 run an NIS server? 842 </a></dt><dt> <a href="net2000users.html#id2589034"> 843 Can I use NIS in place of LDAP? 844 </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="id2588388"></a><a name="id2588390"></a></td><td align="left" valign="top"><p> 845 <a class="indexterm" name="id2588395"></a> 846 <a class="indexterm" name="id2588401"></a> 847 Is it true that DHCP uses lots of WAN bandwidth? 848 </p></td></tr><tr class="answer"><td align="left" valign="top"></td><td align="left" valign="top"><p> 849 <a class="indexterm" name="id2588418"></a> 850 <a class="indexterm" name="id2588427"></a> 851 <a class="indexterm" name="id2588434"></a> 852 It is a smart practice to localize DHCP servers on each network segment. As a 853 rule, there should be two DHCP servers per network segment. This means that if 854 one server fails, there is always another to service user needs. DHCP requests use 855 only UDP broadcast protocols. It is possible to run a DHCP Relay Agent on network 856 routers. This makes it possible to run fewer DHCP servers. 857 </p><p> 858 <a class="indexterm" name="id2588453"></a> 859 <a class="indexterm" name="id2588462"></a> 860 A DHCP network address request and confirmation usually results in about six UDP packets. 861 The packets are from 60 to 568 bytes in length. Let us consider a site that has 300 DHCP 862 clients and that uses a 24-hour IP address lease. This means that all clients renew 863 their IP address lease every 24 hours. If we assume an average packet length equal to the 864 maximum (just to be on the safe side), and we have a 128 Kb/sec wide-area connection, 865 how significant would the DHCP traffic be if all of it were to use DHCP Relay? 866 </p><p> 867 I must stress that this is a bad design, but here is the calculation: 868</p><pre class="screen"> 869Daily Network Capacity: 128,000 (Kbits/s) / 8 (bits/byte) 870 x 3600 (sec/hr) x 24 (hrs/day)= 2288 Mbytes/day. 871 872DHCP traffic: 300 (clients) x 6 (packets) 873 x 512 (bytes/packet) = 0.9 Mbytes/day. 874</pre><p> 875 From this can be seen that the traffic impact would be minimal. 876 </p><p> 877 <a class="indexterm" name="id2588500"></a> 878 <a class="indexterm" name="id2588509"></a> 879 Even when DHCP is configured to do DNS update (dynamic DNS) over a wide-area link, 880 the impact of the update is no more than the DHCP IP address renewal traffic and thus 881 still insignificant for most practical purposes. 882 </p></td></tr><tr class="question"><td align="left" valign="top"><a name="id2588523"></a><a name="id2588525"></a></td><td align="left" valign="top"><p> 883 <a class="indexterm" name="id2588529"></a> 884 <a class="indexterm" name="id2588536"></a> 885 How much background communication takes place between a master LDAP server and its slave LDAP servers? 886 </p></td></tr><tr class="answer"><td align="left" valign="top"></td><td align="left" valign="top"><p> 887 <a class="indexterm" name="id2588557"></a> 888 The process that controls the replication of data from the master LDAP server to the slave LDAP 889 servers is called <code class="literal">slurpd</code>. The <code class="literal">slurpd</code> remains nascent (quiet) 890 until an update must be propagated. The propagation traffic per LDAP slave to update (add/modify/delete) 891 two user accounts requires less than 10KB traffic. 892 </p></td></tr><tr class="question"><td align="left" valign="top"><a name="id2588584"></a><a name="id2588586"></a></td><td align="left" valign="top"><p> 893 LDAP has a database. Is LDAP not just a fancy database front end? 894 </p></td></tr><tr class="answer"><td align="left" valign="top"></td><td align="left" valign="top"><p> 895 <a class="indexterm" name="id2588598"></a> 896 <a class="indexterm" name="id2588605"></a> 897 <a class="indexterm" name="id2588614"></a> 898 <a class="indexterm" name="id2588620"></a> 899 LDAP does store its data in a database of sorts. In fact, the LDAP backend is an application-specific 900 data storage system. This type of database is indexed so that records can be rapidly located, but the 901 database is not generic and can be used only in particular pre-programmed ways. General external 902 applications do not gain access to the data. This type of database is used also by SQL servers. Both 903 an SQL server and an LDAP server provide ways to access the data. An SQL server has a transactional 904 orientation and typically allows external programs to perform ad hoc queries, even across data tables. 905 An LDAP front end is a purpose-built tool that has a search orientation that is designed around specific 906 simple queries. The term <code class="constant">database</code> is heavily overloaded and thus much misunderstood. 907 </p></td></tr><tr class="question"><td align="left" valign="top"><a name="id2588648"></a><a name="id2588650"></a></td><td align="left" valign="top"><p> 908 <a class="indexterm" name="id2588654"></a> 909 Can Active Directory obtain account information from an OpenLDAP server? 910 </p></td></tr><tr class="answer"><td align="left" valign="top"></td><td align="left" valign="top"><p> 911 <a class="indexterm" name="id2588669"></a> 912 No, at least not directly. It is possible to provision Active Directory from and/or to an OpenLDAP 913 database through use of a metadirectory server. Microsoft MMS (now called MIIS) can interface 914 to OpenLDAP using standard LDAP queries and updates. 915 </p></td></tr><tr class="question"><td align="left" valign="top"><a name="id2588683"></a><a name="id2588685"></a></td><td align="left" valign="top"><p> 916 What are the parts of a roaming profile? How large is each part? 917 </p></td></tr><tr class="answer"><td align="left" valign="top"></td><td align="left" valign="top"><p><a class="indexterm" name="id2588696"></a> 918 A roaming profile consists of 919 </p><div class="itemizedlist"><ul type="disc"><li><p> 920 Desktop folders such as <code class="constant">Desktop</code>, <code class="constant">My Documents</code>, 921 <code class="constant">My Pictures</code>, <code class="constant">My Music</code>, <code class="constant">Internet Files</code>, 922 <code class="constant">Cookies</code>, <code class="constant">Application Data</code>, 923 <code class="constant">Local Settings,</code> and more. See <a class="link" href="happy.html" title="Chapter�5.�Making Happy Users">“Making Happy Users”</a>, <a class="link" href="happy.html#XP-screen001" title="Figure�5.3.�Windows XP Professional User Shared Folders">“Windows XP Professional User Shared Folders”</a>. 924 </p><p> 925 <a class="indexterm" name="id2588757"></a> 926 Each of these can be anywhere from a few bytes to gigabytes in capacity. Fortunately, all 927 such folders can be redirected to network drive resources. See <a class="link" href="happy.html#redirfold" title="Configuration of Default Profile with Folder Redirection">“Configuration of Default Profile with Folder Redirection”</a> 928 for more information regarding folder redirection. 929 </p></li><li><p> 930 A static or rewritable portion that is typically only a few files (2-5 KB of information). 931 </p></li><li><p> 932 <a class="indexterm" name="id2588784"></a> 933 <a class="indexterm" name="id2588790"></a> 934 The registry load file that modifies the <code class="constant">HKEY_LOCAL_USER</code> hive. This is 935 the <code class="filename">NTUSER.DAT</code> file. It can be from 0.4 to 1.5 MB. 936 </p></li></ul></div><p> 937 <a class="indexterm" name="id2588813"></a> 938 Microsoft Outlook PST files may be stored in the <code class="constant">Local Settings\Application Data</code> 939 folder. It can be up to 2 GB in size per PST file. 940 </p></td></tr><tr class="question"><td align="left" valign="top"><a name="id2588832"></a><a name="id2588834"></a></td><td align="left" valign="top"><p> 941 Can the <code class="constant">My Documents</code> folder be stored on a network drive? 942 </p></td></tr><tr class="answer"><td align="left" valign="top"></td><td align="left" valign="top"><p> 943 <a class="indexterm" name="id2588849"></a> 944 <a class="indexterm" name="id2588856"></a> 945 Yes. More correctly, such folders can be redirected to network shares. No specific network drive 946 connection is required. Registry settings permit this to be redirected directly to a UNC (Universal 947 Naming Convention) resource, though it is possible to specify a network drive letter instead of a 948 UNC name. See <a class="link" href="happy.html#redirfold" title="Configuration of Default Profile with Folder Redirection">“Configuration of Default Profile with Folder Redirection”</a>. 949 </p></td></tr><tr class="question"><td align="left" valign="top"><a name="id2588880"></a><a name="id2588882"></a></td><td align="left" valign="top"><p> 950 <a class="indexterm" name="id2588886"></a> 951 <a class="indexterm" name="id2588893"></a> 952 <a class="indexterm" name="id2588902"></a> 953 How much WAN bandwidth does WINS consume? 954 </p></td></tr><tr class="answer"><td align="left" valign="top"></td><td align="left" valign="top"><p> 955 <a class="indexterm" name="id2588916"></a> 956 <a class="indexterm" name="id2588925"></a> 957 <a class="indexterm" name="id2588932"></a> 958 MS Windows clients cache information obtained from WINS lookups in a local NetBIOS name cache. 959 This keeps WINS lookups to a minimum. On a network with 3500 MS Windows clients and a central WINS 960 server, the total bandwidth demand measured at the WINS server, averaged over an 8-hour working day, 961 was less than 30 KB/sec. Analysis of network traffic over a 6-week period showed that the total 962 of all background traffic consumed about 11 percent of available bandwidth over 64 Kb/sec links. 963 Background traffic consisted of domain replication, WINS queries, DNS lookups, and authentication 964 traffic. Each of 11 branch offices had a 64 Kb/sec wide-area link, with a 1.5 Mb/sec main connection 965 that aggregated the branch office connections plus an Internet connection. 966 </p><p> 967 In conclusion, the total load afforded through WINS traffic is again marginal to total operational 968 usage as it should be. 969 </p></td></tr><tr class="question"><td align="left" valign="top"><a name="id2588964"></a><a name="id2588966"></a></td><td align="left" valign="top"><p> 970 How many BDCs should I have? What is the right number of Windows clients per server? 971 </p></td></tr><tr class="answer"><td align="left" valign="top"></td><td align="left" valign="top"><p> 972 It is recommended to have at least one BDC per network segment, including the segment served 973 by the PDC. Actual requirements vary depending on the working load on each of the BDCs and the 974 load demand pattern of client usage. I have seen sites that function without problem with 200 975 clients served by one BDC, and yet other sites that had one BDC per 20 clients. In one particular 976 company, there was a drafting office that had 30 CAD/CAM operators served by one server, a print 977 server; and an application server. While all three were BDCs, typically only the print server would 978 service network logon requests after the first 10 users had started to use the network. This was 979 a reflection of the service load placed on both the application server and the data server. 980 </p><p> 981 As unsatisfactory as the answer might sound, it all depends on network and server load 982 characteristics. 983 </p></td></tr><tr class="question"><td align="left" valign="top"><a name="id2589000"></a><a name="id2589002"></a></td><td align="left" valign="top"><p> 984 <a class="indexterm" name="id2589006"></a><a class="indexterm" name="id2589012"></a> 985 I've heard that you can store NIS accounts in LDAP. Is LDAP not just a smarter way to 986 run an NIS server? 987 </p></td></tr><tr class="answer"><td align="left" valign="top"></td><td align="left" valign="top"><p> 988 The correct answer to both questions is yes. But do understand that an LDAP server has 989 a configurable schema that can store far more information for many more purposes than 990 just NIS. 991 </p></td></tr><tr class="question"><td align="left" valign="top"><a name="id2589034"></a><a name="id2589036"></a></td><td align="left" valign="top"><p> 992 Can I use NIS in place of LDAP? 993 </p></td></tr><tr class="answer"><td align="left" valign="top"></td><td align="left" valign="top"><p> 994 <a class="indexterm" name="id2589047"></a> 995 <a class="indexterm" name="id2589054"></a> 996 No. The NIS database does not have provision to store Microsoft encrypted passwords and does not deal 997 with the types of data necessary for interoperability with Microsoft Windows networking. The use 998 of LDAP with Samba requires the use of a number of schemas, one of which is the NIS schema, but also 999 a Samba-specific schema extension. 1000 </p></td></tr></tbody></table></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="happy.html">Prev</a>�</td><td width="20%" align="center"><a accesskey="u" href="ExNetworks.html">Up</a></td><td width="40%" align="right">�<a accesskey="n" href="DMSMig.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter�5.�Making Happy Users�</td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top">�Part�II.�Domain Members, Updating Samba and Migration</td></tr></table></div></body></html> 1001
