1<?xml version="1.0" encoding="iso-8859-1"?> 2<!DOCTYPE chapter PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc"> 3<chapter id="integrate-ms-networks"> 4 5<chapterinfo> 6 &author.jht; 7 <pubdate> (Jan 01 2001) </pubdate> 8</chapterinfo> 9 10<title>Integrating MS Windows Networks with Samba</title> 11 12<para> 13<indexterm><primary>NetBIOS</primary></indexterm> 14This chapter deals with NetBIOS over TCP/IP name to IP address resolution. If 15your MS Windows clients are not configured to use NetBIOS over TCP/IP, then this 16section does not apply to your installation. If your installation involves the use of 17NetBIOS over TCP/IP, then this chapter may help you to resolve networking problems. 18</para> 19 20<note> 21<para> 22<indexterm><primary>NetBEUI</primary></indexterm> 23<indexterm><primary>LLC</primary></indexterm> 24NetBIOS over TCP/IP has nothing to do with NetBEUI. NetBEUI is NetBIOS 25over Logical Link Control (LLC). On modern networks it is highly advised 26to not run NetBEUI at all. Note also that there is no such thing as 27NetBEUI over TCP/IP &smbmdash; the existence of such a protocol is a complete 28and utter misapprehension. 29</para> 30</note> 31 32<sect1> 33<title>Features and Benefits</title> 34 35<para> 36Many MS Windows network administrators have never been exposed to basic TCP/IP 37networking as it is implemented in a UNIX/Linux operating system. Likewise, many UNIX and 38Linux administrators have not been exposed to the intricacies of MS Windows TCP/IP-based 39networking (and may have no desire to be, either). 40</para> 41 42<para> 43This chapter gives a short introduction to the basics of how a name can be resolved to 44its IP address for each operating system environment. 45</para> 46 47</sect1> 48 49<sect1> 50<title>Background Information</title> 51 52<para> 53<indexterm><primary>NetBIOS over TCP/IP</primary></indexterm> 54<indexterm><primary>UDP port 137</primary></indexterm> 55<indexterm><primary>TCP port 139</primary></indexterm> 56<indexterm><primary>TCP port 445</primary></indexterm> 57<indexterm><primary>UDP port 137</primary></indexterm> 58Since the introduction of MS Windows 2000, it is possible to run MS Windows networking 59without the use of NetBIOS over TCP/IP. NetBIOS over TCP/IP uses UDP port 137 for NetBIOS 60name resolution and uses TCP port 139 for NetBIOS session services. When NetBIOS over 61TCP/IP is disabled on MS Windows 2000 and later clients, then only the TCP port 445 is 62used, and the UDP port 137 and TCP port 139 are not. 63</para> 64 65<note> 66<para> 67When using Windows 2000 or later clients, if NetBIOS over TCP/IP is not disabled, then 68the client will use UDP port 137 (NetBIOS Name Service, also known as the Windows Internet 69Name Service, or WINS), TCP port 139, and TCP port 445 (for actual file and print traffic). 70</para> 71</note> 72 73<para> 74<indexterm><primary>DNS</primary></indexterm> 75<indexterm><primary>ADS</primary></indexterm> 76<indexterm><primary>DDNS</primary></indexterm> 77<indexterm><primary>SRV RR</primary></indexterm> 78<indexterm><primary>IXFR</primary></indexterm> 79<indexterm><primary>DHCP</primary></indexterm> 80When NetBIOS over TCP/IP is disabled, the use of DNS is essential. Most installations that disable NetBIOS 81over TCP/IP today use MS Active Directory Service (ADS). ADS requires 82<indexterm><primary>DNS</primary><secondary>Dynamic</secondary></indexterm> dynamic DNS with Service Resource 83Records (SRV RR) and with Incremental Zone Transfers (IXFR). <indexterm><primary>DHCP</primary></indexterm> 84Use of DHCP with ADS is recommended as a further means of maintaining central control over the client 85workstation network configuration. 86</para> 87 88</sect1> 89 90<sect1> 91<title>Name Resolution in a Pure UNIX/Linux World</title> 92 93<para> 94The key configuration files covered in this section are: 95</para> 96 97<indexterm><primary>/etc/hosts</primary></indexterm> 98<indexterm><primary>/etc/resolv.conf</primary></indexterm> 99<indexterm><primary>/etc/host.conf</primary></indexterm> 100<indexterm><primary>/etc/nsswitch.conf</primary></indexterm> 101 102<itemizedlist> 103 <listitem><para><filename>/etc/hosts</filename></para></listitem> 104 <listitem><para><filename>/etc/resolv.conf</filename></para></listitem> 105 <listitem><para><filename>/etc/host.conf</filename></para></listitem> 106 <listitem><para><filename>/etc/nsswitch.conf</filename></para></listitem> 107</itemizedlist> 108 109<sect2> 110<title><filename>/etc/hosts</filename></title> 111 112<para> 113This file contains a static list of IP addresses and names. 114<programlisting> 115127.0.0.1 localhost localhost.localdomain 116192.168.1.1 bigbox.quenya.org bigbox alias4box 117</programlisting> 118</para> 119 120<para> 121<indexterm><primary>/etc/hosts></primary></indexterm> 122<indexterm><primary>name resolution</primary></indexterm> 123The purpose of <filename>/etc/hosts</filename> is to provide a 124name resolution mechanism so users do not need to remember 125IP addresses. 126</para> 127 128<para> 129<indexterm><primary>IP addresses</primary></indexterm> 130<indexterm><primary>MAC address</primary></indexterm> 131<indexterm><primary>physical network transport layer</primary></indexterm> 132Network packets that are sent over the physical network transport 133layer communicate not via IP addresses but rather using the Media 134Access Control address, or MAC address. IP addresses are currently 13532 bits in length and are typically presented as four decimal 136numbers that are separated by a dot (or period) &smbmdash; for example, 168.192.1.1. 137</para> 138 139<para> 140<indexterm><primary>MAC Addresses</primary></indexterm> 141MAC addresses use 48 bits (or 6 bytes) and are typically represented 142as two-digit hexadecimal numbers separated by colons: 40:8e:0a:12:34:56. 143</para> 144 145<para> 146Every network interface must have a MAC address. Associated with a MAC address may be one or more IP 147addresses. There is no relationship between an IP address and a MAC address; all such assignments are 148arbitrary or discretionary in nature. At the most basic level, all network communications take place using MAC 149addressing. Since MAC addresses must be globally unique and generally remain fixed for any particular 150interface, the assignment of an IP address makes sense from a network management perspective. More than one IP 151address can be assigned per MAC address. One address must be the primary IP address &smbmdash; this is the 152address that will be returned in the Address Resolution Protocol (ARP) reply. 153</para> 154 155<para> 156<indexterm><primary>machine name</primary></indexterm> 157When a user or a process wants to communicate with another machine, 158the protocol implementation ensures that the <quote>machine name</quote> or <quote>host 159name</quote> is resolved to an IP address in a manner that is controlled 160by the TCP/IP configuration control files. The file 161<filename>/etc/hosts</filename> is one such file. 162</para> 163 164<para> 165<indexterm><primary>ARP/RARP</primary></indexterm> 166When the IP address of the destination interface has been determined, a protocol called ARP/RARP is used to 167identify the MAC address of the target interface. ARP is a broadcast-oriented method that uses User Datagram 168Protocol (UDP) to send a request to all interfaces on the local network segment using the all 1s MAC address. 169Network interfaces are programmed to respond to two MAC addresses only; their own unique address and the 170address ff:ff:ff:ff:ff:ff. The reply packet from an ARP request will contain the MAC address and the primary 171IP address for each interface. 172</para> 173 174<para> 175<indexterm><primary>/etc/hosts</primary></indexterm> 176The <filename>/etc/hosts</filename> file is foundational to all 177UNIX/Linux TCP/IP installations and as a minimum will contain 178the localhost and local network interface IP addresses and the 179primary names by which they are known within the local machine. 180This file helps to prime the pump so a basic level of name 181resolution can exist before any other method of name resolution 182becomes available. 183</para> 184 185</sect2> 186 187 188<sect2> 189<title><filename>/etc/resolv.conf</filename></title> 190 191<para> 192This file tells the name resolution libraries: 193</para> 194 195<itemizedlist> 196 <listitem><para>The name of the domain to which the machine 197 belongs. 198 </para></listitem> 199 200 <listitem><para>The name(s) of any domains that should be 201 automatically searched when trying to resolve unqualified 202 host names to their IP address. 203 </para></listitem> 204 205 <listitem><para>The name or IP address of available domain 206 name servers that may be asked to perform name-to-address 207 translation lookups. 208 </para></listitem> 209</itemizedlist> 210 211</sect2> 212 213 214<sect2> 215<title><filename>/etc/host.conf</filename></title> 216 217 218<para> 219<indexterm><primary>/etc/host.conf</primary></indexterm> 220<filename>/etc/host.conf</filename> is the primary means by which the setting in 221<filename>/etc/resolv.conf</filename> may be effected. It is a critical configuration file. This file controls 222the order by which name resolution may proceed. The typical structure is: 223<programlisting> 224order hosts,bind 225multi on 226</programlisting></para> 227 228<para>Both addresses should be returned. Please refer to the 229man page for <filename>host.conf</filename> for further details. 230</para> 231 232</sect2> 233 234 235<sect2> 236<title><filename>/etc/nsswitch.conf</filename></title> 237 238<para> 239<indexterm><primary>/etc/nsswitch.conf</primary></indexterm> 240This file controls the actual name resolution targets. The 241file typically has resolver object specifications as follows: 242<programlisting> 243# /etc/nsswitch.conf 244# 245# Name Service Switch configuration file. 246# 247 248passwd: compat 249# Alternative entries for password authentication are: 250# passwd: compat files nis ldap winbind 251shadow: compat 252group: compat 253 254hosts: files nis dns 255# Alternative entries for host name resolution are: 256# hosts: files dns nis nis+ hesiod db compat ldap wins 257networks: nis files dns 258 259ethers: nis files 260protocols: nis files 261rpc: nis files 262services: nis files 263</programlisting></para> 264 265<para> 266Of course, each of these mechanisms requires that the appropriate 267facilities and/or services are correctly configured. 268</para> 269 270<para> 271It should be noted that unless a network request/message must be 272sent, TCP/IP networks are silent. All TCP/IP communications assume a 273principal of speaking only when necessary. 274</para> 275 276 277<para> 278<indexterm><primary>libnss_wins.so</primary></indexterm> 279<indexterm><primary>NetBIOS names</primary></indexterm> 280<indexterm><primary>make</primary></indexterm> 281<indexterm><primary>/etc/nsswitch.conf</primary></indexterm> 282<indexterm><primary>wins</primary></indexterm> 283Starting with version 2.2.0, Samba has Linux support for extensions to 284the name service switch infrastructure so Linux clients will 285be able to obtain resolution of MS Windows NetBIOS names to IP 286addresses. To gain this functionality, Samba needs to be compiled 287with appropriate arguments to the make command (i.e., <userinput>make 288nsswitch/libnss_wins.so</userinput>). The resulting library should 289then be installed in the <filename>/lib</filename> directory, and 290the <parameter>wins</parameter> parameter needs to be added to the <quote>hosts:</quote> line in 291the <filename>/etc/nsswitch.conf</filename> file. At this point, it 292will be possible to ping any MS Windows machine by its NetBIOS 293machine name, as long as that machine is within the workgroup to 294which both the Samba machine and the MS Windows machine belong. 295</para> 296 297</sect2> 298</sect1> 299 300 301<sect1> 302<title>Name Resolution as Used within MS Windows Networking</title> 303 304<para> 305<indexterm><primary>computer name</primary></indexterm> 306<indexterm><primary>machine name</primary></indexterm> 307<indexterm><primary>NetBIOS name</primary></indexterm> 308<indexterm><primary>SMB name</primary></indexterm> 309MS Windows networking is predicated on the name each machine is given. This name is known variously (and 310inconsistently) as the <quote>computer name,</quote> <quote>machine name,</quote> <quote>networking 311name,</quote> <quote>NetBIOS name,</quote> or <quote>SMB name.</quote> All terms mean the same thing with the 312exception of <quote>NetBIOS name,</quote> which can also apply to the name of the workgroup or the domain 313name. The terms <quote>workgroup</quote> and <quote>domain</quote> are really just a simple name with which 314the machine is associated. All NetBIOS names are exactly 16 characters in length. The 31516<superscript>th</superscript> character is reserved. It is used to store a 1-byte value that indicates 316service level information for the NetBIOS name that is registered. A NetBIOS machine name is therefore 317registered for each service type that is provided by the client/server. 318</para> 319 320<para> 321<link linkend="uniqnetbiosnames">Unique NetBIOS names</link> and <link linkend="netbiosnamesgrp">group names</link> tables 322list typical NetBIOS name/service type registrations. 323</para> 324 325<table frame="all" id="uniqnetbiosnames"> 326<title>Unique NetBIOS Names</title> 327<tgroup cols="2"> 328<colspec align="left"/> 329<colspec align="justify"/> 330<tbody> 331<row><entry>MACHINENAME<00></entry><entry>Server Service is running on MACHINENAME</entry></row> 332<row><entry>MACHINENAME<03></entry><entry>Generic machine name (NetBIOS name)</entry></row> 333<row><entry>MACHINENAME<20></entry><entry>LanMan server service is running on MACHINENAME</entry></row> 334<row><entry>WORKGROUP<1b></entry><entry>Domain master browser</entry></row> 335</tbody> 336</tgroup> 337</table> 338 339<table frame="all" id="netbiosnamesgrp"> 340<title>Group Names</title> 341<tgroup cols="2"> 342<colspec align="left"/> 343<colspec align="justify"/> 344<tbody> 345<row><entry>WORKGROUP<03></entry><entry>Generic name registered by all members of WORKGROUP</entry></row> 346<row><entry>WORKGROUP<1c></entry><entry>Domain cntrollers/netlogon servers</entry></row> 347<row><entry>WORKGROUP<1d></entry><entry>Local master browsers</entry></row> 348<row><entry>WORKGROUP<1e></entry><entry>Browser election service</entry></row> 349</tbody> 350</tgroup> 351</table> 352 353<para> 354<indexterm><primary>NetBIOS</primary></indexterm> 355It should be noted that all NetBIOS machines register their own 356names as per <link linkend="uniqnetbiosnames">Unique NetBIOS names</link> and <link 357linkend="netbiosnamesgrp">group names</link>. This is in vast contrast to TCP/IP 358installations where the system administrator traditionally 359determines in the <filename>/etc/hosts</filename> or in the DNS database what names 360are associated with each IP address. 361</para> 362 363<para> 364<indexterm><primary>NetBIOS</primary></indexterm> 365<indexterm><primary>/etc/hosts</primary></indexterm> 366<indexterm><primary>NetBIOS name</primary></indexterm> 367One further point of clarification should be noted. The <filename>/etc/hosts</filename> 368file and the DNS records do not provide the NetBIOS name information 369that MS Windows clients depend on to locate the type of service that may 370be needed. An example of this is what happens when an MS Windows client 371wants to locate a domain logon server. It finds this service and the IP 372address of a server that provides it by performing a lookup (via a 373NetBIOS broadcast) for enumeration of all machines that have 374registered the name type *<1C>. A logon request is then sent to each 375IP address that is returned in the enumerated list of IP addresses. 376Whichever machine first replies, it then ends up providing the logon services. 377</para> 378 379<para> 380<indexterm><primary>domain</primary></indexterm> 381<indexterm><primary>workgroup</primary></indexterm> 382The name <quote>workgroup</quote> or <quote>domain</quote> really can be confusing, since these 383have the added significance of indicating what is the security 384architecture of the MS Windows network. The term <quote>workgroup</quote> indicates 385that the primary nature of the network environment is that of a 386peer-to-peer design. In a workgroup, all machines are responsible for 387their own security, and generally such security is limited to the use of 388just a password (known as share-level security). In most situations 389with peer-to-peer networking, the users who control their own machines 390will simply opt to have no security at all. It is possible to have 391user-level security in a workgroup environment, thus requiring the use 392of a username and a matching password. 393</para> 394 395<para> 396<indexterm><primary>SMB</primary></indexterm> 397<indexterm><primary>Network Basic Input/Output System</primary><see>NetBIOS</see></indexterm> 398<indexterm><primary>Logical Link Control</primary><see>LLC</see></indexterm> 399<indexterm><primary>Network Basic Extended User Interface</primary><see>NetBEUI</see></indexterm> 400<indexterm><primary>Internetworking Packet Exchange</primary><see>IPX</see></indexterm> 401<indexterm><primary>NetWare</primary></indexterm> 402<indexterm><primary>NetBT</primary></indexterm> 403<indexterm><primary>NBT</primary></indexterm> 404MS Windows networking is thus predetermined to use machine names 405for all local and remote machine message passing. The protocol used is 406called Server Message Block (SMB), and this is implemented using 407the NetBIOS protocol (Network Basic Input/Output System). NetBIOS can 408be encapsulated using LLC (Logical Link Control) protocol &smbmdash; in which case 409the resulting protocol is called NetBEUI (Network Basic Extended User 410Interface). NetBIOS can also be run over IPX (Internetworking Packet 411Exchange) protocol as used by Novell NetWare, and it can be run 412over TCP/IP protocols &smbmdash; in which case the resulting protocol is called 413NBT or NetBT, the NetBIOS over TCP/IP. 414</para> 415 416<para> 417MS Windows machines use a complex array of name resolution mechanisms. 418Since we are primarily concerned with TCP/IP, this demonstration is 419limited to this area. 420</para> 421 422<sect2> 423<title>The NetBIOS Name Cache</title> 424 425<para> 426<indexterm><primary>n-memory buffer</primary></indexterm> 427<indexterm><primary>local cache</primary></indexterm> 428<indexterm><primary></primary></indexterm> 429All MS Windows machines employ an in-memory buffer in which is 430stored the NetBIOS names and IP addresses for all external 431machines that machine has communicated with over the 432past 10 to 15 minutes. It is more efficient to obtain an IP address 433for a machine from the local cache than it is to go through all the 434configured name resolution mechanisms. 435</para> 436 437<para> 438<indexterm><primary>name lookup</primary></indexterm> 439If a machine whose name is in the local name cache is shut 440down before the name is expired and flushed from the cache, then 441an attempt to exchange a message with that machine will be subject 442to timeout delays. Its name is in the cache, so a name resolution 443lookup will succeed, but the machine cannot respond. This can be 444frustrating for users but is a characteristic of the protocol. 445</para> 446 447<para> 448<indexterm><primary>nbtstat</primary></indexterm> 449<indexterm><primary>nmblookup</primary></indexterm> 450<indexterm><primary>NetBIOS</primary></indexterm> 451The MS Windows utility that allows examination of the NetBIOS 452name cache is called <quote>nbtstat.</quote> The Samba equivalent 453is called <command>nmblookup</command>. 454</para> 455 456</sect2> 457 458<sect2> 459<title>The LMHOSTS File</title> 460 461<para> 462<indexterm><primary>LMHOSTS</primary></indexterm> 463This file is usually located in MS Windows NT 4.0 or Windows 200x/XP in the directory 464<filename>%SystemRoot%\SYSTEM32\DRIVERS\ETC</filename> and contains the IP address 465and the machine name in matched pairs. The <filename>LMHOSTS</filename> file 466performs NetBIOS name to IP address mapping. 467</para> 468 469<para> 470It typically looks like this: 471</para> 472 473<para><programlisting> 474# Copyright (c) 1998 Microsoft Corp. 475# 476# This is a sample LMHOSTS file used by the Microsoft Wins Client (NetBIOS 477# over TCP/IP) stack for Windows98 478# 479# This file contains the mappings of IP addresses to NT computer names 480# (NetBIOS) names. Each entry should be kept on an individual line. 481# The IP address should be placed in the first column followed by the 482# corresponding computer name. The address and the computer name 483# should be separated by at least one space or tab. The "#" character 484# is generally used to denote the start of a comment (see the exceptions 485# below). 486# 487# This file is compatible with Microsoft LAN Manager 2.x TCP/IP lmhosts 488# files and offers the following extensions: 489# 490# #PRE 491# #DOM:<domain> 492# #INCLUDE <filename> 493# #BEGIN_ALTERNATE 494# #END_ALTERNATE 495# \0xnn (non-printing character support) 496# 497# Following any entry in the file with the characters "#PRE" will cause 498# the entry to be preloaded into the name cache. By default, entries are 499# not preloaded, but are parsed only after dynamic name resolution fails. 500# 501# Following an entry with the "#DOM:<domain>" tag will associate the 502# entry with the domain specified by <domain>. This effects how the 503# browser and logon services behave in TCP/IP environments. To preload 504# the host name associated with #DOM entry, it is necessary to also add a 505# #PRE to the line. The <domain> is always pre-loaded although it will not 506# be shown when the name cache is viewed. 507# 508# Specifying "#INCLUDE <filename>" will force the RFC NetBIOS (NBT) 509# software to seek the specified <filename> and parse it as if it were 510# local. <filename> is generally a UNC-based name, allowing a 511# centralized lmhosts file to be maintained on a server. 512# It is ALWAYS necessary to provide a mapping for the IP address of the 513# server prior to the #INCLUDE. This mapping must use the #PRE directive. 514# In addition the share "public" in the example below must be in the 515# LanMan Server list of "NullSessionShares" in order for client machines to 516# be able to read the lmhosts file successfully. This key is under 517# \machine\system\currentcontrolset\services\lanmanserver\ 518# parameters\nullsessionshares 519# in the registry. Simply add "public" to the list found there. 520# 521# The #BEGIN_ and #END_ALTERNATE keywords allow multiple #INCLUDE 522# statements to be grouped together. Any single successful include 523# will cause the group to succeed. 524# 525# Finally, non-printing characters can be embedded in mappings by 526# first surrounding the NetBIOS name in quotations, then using the 527# \0xnn notation to specify a hex value for a non-printing character. 528# 529# The following example illustrates all of these extensions: 530# 531# 102.54.94.97 rhino #PRE #DOM:networking #net group's DC 532# 102.54.94.102 "appname \0x14" #special app server 533# 102.54.94.123 popular #PRE #source server 534# 102.54.94.117 localsrv #PRE #needed for the include 535# 536# #BEGIN_ALTERNATE 537# #INCLUDE \\localsrv\public\lmhosts 538# #INCLUDE \\rhino\public\lmhosts 539# #END_ALTERNATE 540# 541# In the above example, the "appname" server contains a special 542# character in its name, the "popular" and "localsrv" server names are 543# pre-loaded, and the "rhino" server name is specified so it can be used 544# to later #INCLUDE a centrally maintained lmhosts file if the "localsrv" 545# system is unavailable. 546# 547# Note that the whole file is parsed including comments on each lookup, 548# so keeping the number of comments to a minimum will improve performance. 549# Therefore it is not advisable to simply add lmhosts file entries onto the 550# end of this file. 551</programlisting></para> 552 553</sect2> 554 555<sect2> 556<title>HOSTS File</title> 557 558<para> 559This file is usually located in MS Windows NT 4.0 or Windows 200x/XP in 560the directory <filename>%SystemRoot%\SYSTEM32\DRIVERS\ETC</filename> and contains 561the IP address and the IP hostname in matched pairs. It can be 562used by the name resolution infrastructure in MS Windows, depending 563on how the TCP/IP environment is configured. This file is in 564every way the equivalent of the UNIX/Linux <filename>/etc/hosts</filename> file. 565</para> 566</sect2> 567 568 569<sect2> 570<title>DNS Lookup</title> 571 572 573<para> 574<indexterm><primary>DNS</primary></indexterm> 575This capability is configured in the TCP/IP setup area in the network 576configuration facility. If enabled, an elaborate name resolution sequence 577is followed, the precise nature of which is dependent on how the NetBIOS 578Node Type parameter is configured. A Node Type of 0 means that 579NetBIOS broadcast (over UDP broadcast) is used if the name 580that is the subject of a name lookup is not found in the NetBIOS name 581cache. If that fails, then DNS, HOSTS, and LMHOSTS are checked. If set to 582Node Type 8, then a NetBIOS Unicast (over UDP Unicast) is sent to the 583WINS server to obtain a lookup before DNS, HOSTS, LMHOSTS, or broadcast 584lookup is used. 585</para> 586 587</sect2> 588 589<sect2> 590<title>WINS Lookup</title> 591 592 593<para> 594<indexterm><primary>WINS</primary></indexterm> 595<indexterm><primary>Windows Internet Name Server</primary><see>WINS</see></indexterm> 596<indexterm><primary>NetBIOS Name Server</primary><see>NBNS</see></indexterm> 597A WINS (Windows Internet Name Server) service is the equivalent of the 598rfc1001/1002 specified NBNS (NetBIOS Name Server). A WINS server stores 599the names and IP addresses that are registered by a Windows client 600if the TCP/IP setup has been given at least one WINS server IP address. 601</para> 602 603<para> 604To configure Samba to be a WINS server, the following parameter needs 605to be added to the &smb.conf; file: 606</para> 607 608<para><smbconfblock> 609<smbconfoption name="wins support">Yes</smbconfoption> 610</smbconfblock></para> 611 612<para> 613<indexterm><primary>WINS</primary></indexterm> 614To configure Samba to use a WINS server, the following parameters are 615needed in the &smb.conf; file: 616</para> 617 618<para><smbconfblock> 619<smbconfoption name="wins support">No</smbconfoption> 620<smbconfoption name="wins server">xxx.xxx.xxx.xxx</smbconfoption> 621</smbconfblock></para> 622 623<para> 624where <replaceable>xxx.xxx.xxx.xxx</replaceable> is the IP address 625of the WINS server. 626</para> 627 628<para>For information about setting up Samba as a WINS server, read 629<link linkend="NetworkBrowsing">Network Browsing</link>.</para> 630 631</sect2> 632</sect1> 633 634<sect1> 635<title>Common Errors</title> 636 637<para> 638TCP/IP network configuration problems find every network administrator sooner or later. 639The cause can be anything from keyboard mishaps to forgetfulness to simple mistakes to 640carelessness. Of course, no one is ever deliberately careless! 641</para> 642 643 <sect2> 644 <title>Pinging Works Only One Way</title> 645 646 <para> 647 <quote>I can ping my Samba server from Windows, but I cannot ping my Windows 648 machine from the Samba server.</quote> 649 </para> 650 651 <para> 652 The Windows machine was at IP address 192.168.1.2 with netmask 255.255.255.0, the 653 Samba server (Linux) was at IP address 192.168.1.130 with netmask 255.255.255.128. 654 The machines were on a local network with no external connections. 655 </para> 656 657 <para> 658 Due to inconsistent netmasks, the Windows machine was on network 192.168.1.0/24, while 659 the Samba server was on network 192.168.1.128/25 &smbmdash; logically a different network. 660 </para> 661 662 </sect2> 663 664 <sect2> 665 <title>Very Slow Network Connections</title> 666 667 <para> 668 A common cause of slow network response includes: 669 </para> 670 671 <itemizedlist> 672 <listitem><para>Client is configured to use DNS and the DNS server is down.</para></listitem> 673 <listitem><para>Client is configured to use remote DNS server, but the 674 remote connection is down.</para></listitem> 675 <listitem><para>Client is configured to use a WINS server, but there is no WINS server.</para></listitem> 676 <listitem><para>Client is not configured to use a WINS server, but there is a WINS server.</para></listitem> 677 <listitem><para>Firewall is filtering out DNS or WINS traffic.</para></listitem> 678 </itemizedlist> 679 680 </sect2> 681 682 <sect2> 683 <title>Samba Server Name-Change Problem</title> 684 685 <para> 686 <quote>The name of the Samba server was changed, Samba was restarted, and now the Samba server cannot be 687 pinged by its new name from an MS Windows NT4 workstation, but it does still respond to pinging using 688 the old name. Why?</quote> 689 </para> 690 691 <para> 692 From this description, three things are obvious: 693 </para> 694 695 <itemizedlist> 696 <listitem><para>WINS is not in use; only broadcast-based name resolution is used.</para></listitem> 697 <listitem><para>The Samba server was renamed and restarted within the last 10 or 15 minutes.</para></listitem> 698 <listitem><para>The old Samba server name is still in the NetBIOS name cache on the MS Windows NT4 workstation.</para></listitem> 699 </itemizedlist> 700 701 <para> 702 To find what names are present in the NetBIOS name cache on the MS Windows NT4 machine, 703 open a <command>cmd</command> shell and then: 704 </para> 705 706 <para> 707<screen> 708&dosprompt;<userinput>nbtstat -n</userinput> 709 710 NetBIOS Local Name Table 711 712 Name Type Status 713------------------------------------------------ 714&example.workstation.windows; <03> UNIQUE Registered 715ADMINISTRATOR <03> UNIQUE Registered 716&example.workstation.windows; <00> UNIQUE Registered 717SARDON <00> GROUP Registered 718&example.workstation.windows; <20> UNIQUE Registered 719&example.workstation.windows; <1F> UNIQUE Registered 720 721 722&dosprompt;nbtstat -c 723 724 NetBIOS Remote Cache Name Table 725 726 Name Type Host Address Life [sec] 727-------------------------------------------------------------- 728&example.server.samba; <20> UNIQUE 192.168.1.1 240 729 730&dosprompt; 731</screen> 732 </para> 733 734 <para> 735 In this example, &example.server.samba; is the Samba server and &example.workstation.windows; is the MS Windows NT4 workstation. 736 The first listing shows the contents of the Local Name Table (i.e., identity information on 737 the MS Windows workstation), and the second shows the NetBIOS name in the NetBIOS name cache. 738 The name cache contains the remote machines known to this workstation. 739 </para> 740 741 </sect2> 742 743</sect1> 744 745</chapter> 746