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<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Chapter 29. Integrating MS Windows Networks with Samba</title><link rel="stylesheet" href="samba.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.71.0"><link rel="start" href="index.html" title="The Official Samba-3 HOWTO and Reference Guide"><link rel="up" href="optional.html" title="Part III. Advanced Configuration"><link rel="prev" href="pam.html" title="Chapter 28. PAM-Based Distributed Authentication"><link rel="next" href="unicode.html" title="Chapter 30. Unicode/Charsets"></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 29. Integrating MS Windows Networks with Samba</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="pam.html">Prev</a> </td><th width="60%" align="center">Part III. Advanced Configuration</th><td width="20%" align="right"> <a accesskey="n" href="unicode.html">Next</a></td></tr></table><hr></div><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="integrate-ms-networks"></a>Chapter 29. Integrating MS Windows Networks with Samba</h2></div><div><div class="author"><h3 class="author"><span class="firstname">John</span> <span class="othername">H.</span> <span class="surname">Terpstra</span></h3><div class="affiliation"><span class="orgname">Samba Team<br></span><div class="address"><p><code class="email"><<a href="mailto:jht@samba.org">jht@samba.org</a>></code></p></div></div></div></div><div><p class="pubdate"> (Jan 01 2001) </p></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="sect1"><a href="integrate-ms-networks.html#id424744">Features and Benefits</a></span></dt><dt><span class="sect1"><a href="integrate-ms-networks.html#id424761">Background Information</a></span></dt><dt><span class="sect1"><a href="integrate-ms-networks.html#id424880">Name Resolution in a Pure UNIX/Linux World</a></span></dt><dd><dl><dt><span class="sect2"><a href="integrate-ms-networks.html#id424951"><code class="filename">/etc/hosts</code></a></span></dt><dt><span class="sect2"><a href="integrate-ms-networks.html#id425107"><code class="filename">/etc/resolv.conf</code></a></span></dt><dt><span class="sect2"><a href="integrate-ms-networks.html#id425140"><code class="filename">/etc/host.conf</code></a></span></dt><dt><span class="sect2"><a href="integrate-ms-networks.html#id425188"><code class="filename">/etc/nsswitch.conf</code></a></span></dt></dl></dd><dt><span class="sect1"><a href="integrate-ms-networks.html#id425298">Name Resolution as Used within MS Windows Networking</a></span></dt><dd><dl><dt><span class="sect2"><a href="integrate-ms-networks.html#id425691">The NetBIOS Name Cache</a></span></dt><dt><span class="sect2"><a href="integrate-ms-networks.html#id425770">The LMHOSTS File</a></span></dt><dt><span class="sect2"><a href="integrate-ms-networks.html#id425896">HOSTS File</a></span></dt><dt><span class="sect2"><a href="integrate-ms-networks.html#id425921">DNS Lookup</a></span></dt><dt><span class="sect2"><a href="integrate-ms-networks.html#id425943">WINS Lookup</a></span></dt></dl></dd><dt><span class="sect1"><a href="integrate-ms-networks.html#id426077">Common Errors</a></span></dt><dd><dl><dt><span class="sect2"><a href="integrate-ms-networks.html#id426088">Pinging Works Only One Way</a></span></dt><dt><span class="sect2"><a href="integrate-ms-networks.html#id426116">Very Slow Network Connections</a></span></dt><dt><span class="sect2"><a href="integrate-ms-networks.html#id426154">Samba Server Name-Change Problem</a></span></dt></dl></dd></dl></div><p>
<a class="indexterm" name="id424707"></a>
This chapter deals with NetBIOS over TCP/IP name to IP address resolution. If
your MS Windows clients are not configured to use NetBIOS over TCP/IP, then this
section does not apply to your installation. If your installation involves the use of
NetBIOS over TCP/IP, then this chapter may help you to resolve networking problems.
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
<a class="indexterm" name="id424722"></a>
<a class="indexterm" name="id424729"></a>
NetBIOS over TCP/IP has nothing to do with NetBEUI. NetBEUI is NetBIOS
over Logical Link Control (LLC). On modern networks it is highly advised
to not run NetBEUI at all. Note also that there is no such thing as
NetBEUI over TCP/IP the existence of such a protocol is a complete
and utter misapprehension.
</p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id424744"></a>Features and Benefits</h2></div></div></div><p>
Many MS Windows network administrators have never been exposed to basic TCP/IP
networking as it is implemented in a UNIX/Linux operating system. Likewise, many UNIX and
Linux administrators have not been exposed to the intricacies of MS Windows TCP/IP-based
networking (and may have no desire to be, either).
</p><p>
This chapter gives a short introduction to the basics of how a name can be resolved to
its IP address for each operating system environment.
</p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id424761"></a>Background Information</h2></div></div></div><p>
<a class="indexterm" name="id424768"></a>
<a class="indexterm" name="id424775"></a>
<a class="indexterm" name="id424782"></a>
<a class="indexterm" name="id424789"></a>
<a class="indexterm" name="id424796"></a>
Since the introduction of MS Windows 2000, it is possible to run MS Windows networking
without the use of NetBIOS over TCP/IP. NetBIOS over TCP/IP uses UDP port 137 for NetBIOS
name resolution and uses TCP port 139 for NetBIOS session services. When NetBIOS over
TCP/IP is disabled on MS Windows 2000 and later clients, then only the TCP port 445 is
used, and the UDP port 137 and TCP port 139 are not.
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
When using Windows 2000 or later clients, if NetBIOS over TCP/IP is not disabled, then
the client will use UDP port 137 (NetBIOS Name Service, also known as the Windows Internet
Name Service, or WINS), TCP port 139, and TCP port 445 (for actual file and print traffic).
</p></div><p>
<a class="indexterm" name="id424818"></a>
<a class="indexterm" name="id424824"></a>
<a class="indexterm" name="id424831"></a>
<a class="indexterm" name="id424838"></a>
<a class="indexterm" name="id424844"></a>
<a class="indexterm" name="id424851"></a>
When NetBIOS over TCP/IP is disabled, the use of DNS is essential. Most installations that disable NetBIOS
over TCP/IP today use MS Active Directory Service (ADS). ADS requires
<a class="indexterm" name="id424860"></a> dynamic DNS with Service Resource
Records (SRV RR) and with Incremental Zone Transfers (IXFR). <a class="indexterm" name="id424870"></a>
Use of DHCP with ADS is recommended as a further means of maintaining central control over the client
workstation network configuration.
</p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id424880"></a>Name Resolution in a Pure UNIX/Linux World</h2></div></div></div><p>
The key configuration files covered in this section are:
</p><a class="indexterm" name="id424890"></a><a class="indexterm" name="id424896"></a><a class="indexterm" name="id424903"></a><a class="indexterm" name="id424910"></a><div class="itemizedlist"><ul type="disc"><li><p><code class="filename">/etc/hosts</code></p></li><li><p><code class="filename">/etc/resolv.conf</code></p></li><li><p><code class="filename">/etc/host.conf</code></p></li><li><p><code class="filename">/etc/nsswitch.conf</code></p></li></ul></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id424951"></a><code class="filename">/etc/hosts</code></h3></div></div></div><p>
This file contains a static list of IP addresses and names.
</p><pre class="programlisting">
127.0.0.1 localhost localhost.localdomain
192.168.1.1 bigbox.quenya.org bigbox alias4box
</pre><p>
</p><p>
<a class="indexterm" name="id424973"></a>
<a class="indexterm" name="id424980"></a>
The purpose of <code class="filename">/etc/hosts</code> is to provide a
name resolution mechanism so users do not need to remember
IP addresses.
</p><p>
<a class="indexterm" name="id424996"></a>
<a class="indexterm" name="id425003"></a>
<a class="indexterm" name="id425010"></a>
Network packets that are sent over the physical network transport
layer communicate not via IP addresses but rather using the Media
Access Control address, or MAC address. IP addresses are currently
32 bits in length and are typically presented as four decimal
numbers that are separated by a dot (or period) for example, 168.192.1.1.
</p><p>
<a class="indexterm" name="id425026"></a>
MAC addresses use 48 bits (or 6 bytes) and are typically represented
as two-digit hexadecimal numbers separated by colons: 40:8e:0a:12:34:56.
</p><p>
Every network interface must have a MAC address. Associated with a MAC address may be one or more IP
addresses. There is no relationship between an IP address and a MAC address; all such assignments are
arbitrary or discretionary in nature. At the most basic level, all network communications take place using MAC
addressing. Since MAC addresses must be globally unique and generally remain fixed for any particular
interface, the assignment of an IP address makes sense from a network management perspective. More than one IP
address can be assigned per MAC address. One address must be the primary IP address this is the
address that will be returned in the Address Resolution Protocol (ARP) reply.
</p><p>
<a class="indexterm" name="id425049"></a>
When a user or a process wants to communicate with another machine,
the protocol implementation ensures that the “<span class="quote">machine name</span>” or “<span class="quote">host
name</span>” is resolved to an IP address in a manner that is controlled
by the TCP/IP configuration control files. The file
<code class="filename">/etc/hosts</code> is one such file.
</p><p>
<a class="indexterm" name="id425074"></a>
When the IP address of the destination interface has been determined, a protocol called ARP/RARP is used to
identify the MAC address of the target interface. ARP is a broadcast-oriented method that uses User Datagram
Protocol (UDP) to send a request to all interfaces on the local network segment using the all 1s MAC address.
Network interfaces are programmed to respond to two MAC addresses only; their own unique address and the
address ff:ff:ff:ff:ff:ff. The reply packet from an ARP request will contain the MAC address and the primary
IP address for each interface.
</p><p>
<a class="indexterm" name="id425089"></a>
The <code class="filename">/etc/hosts</code> file is foundational to all
UNIX/Linux TCP/IP installations and as a minimum will contain
the localhost and local network interface IP addresses and the
primary names by which they are known within the local machine.
This file helps to prime the pump so a basic level of name
resolution can exist before any other method of name resolution
becomes available.
</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id425107"></a><code class="filename">/etc/resolv.conf</code></h3></div></div></div><p>
This file tells the name resolution libraries:
</p><div class="itemizedlist"><ul type="disc"><li><p>The name of the domain to which the machine
belongs.
</p></li><li><p>The name(s) of any domains that should be
automatically searched when trying to resolve unqualified
host names to their IP address.
</p></li><li><p>The name or IP address of available domain
name servers that may be asked to perform name-to-address
translation lookups.
</p></li></ul></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id425140"></a><code class="filename">/etc/host.conf</code></h3></div></div></div><p>
<a class="indexterm" name="id425151"></a>
<code class="filename">/etc/host.conf</code> is the primary means by which the setting in
<code class="filename">/etc/resolv.conf</code> may be effected. It is a critical configuration file. This file controls
the order by which name resolution may proceed. The typical structure is:
</p><pre class="programlisting">
order hosts,bind
multi on
</pre><p>Both addresses should be returned. Please refer to the
man page for <code class="filename">host.conf</code> for further details.
</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id425188"></a><code class="filename">/etc/nsswitch.conf</code></h3></div></div></div><p>
<a class="indexterm" name="id425199"></a>
This file controls the actual name resolution targets. The
file typically has resolver object specifications as follows:
</p><pre class="programlisting">
# /etc/nsswitch.conf
#
# Name Service Switch configuration file.
#
passwd: compat
# Alternative entries for password authentication are:
# passwd: compat files nis ldap winbind
shadow: compat
group: compat
hosts: files nis dns
# Alternative entries for host name resolution are:
# hosts: files dns nis nis+ hesiod db compat ldap wins
networks: nis files dns
ethers: nis files
protocols: nis files
rpc: nis files
services: nis files
</pre><p>
Of course, each of these mechanisms requires that the appropriate
facilities and/or services are correctly configured.
</p><p>
It should be noted that unless a network request/message must be
sent, TCP/IP networks are silent. All TCP/IP communications assume a
principal of speaking only when necessary.
</p><p>
<a class="indexterm" name="id425228"></a>
<a class="indexterm" name="id425235"></a>
<a class="indexterm" name="id425242"></a>
<a class="indexterm" name="id425248"></a>
<a class="indexterm" name="id425255"></a>
Starting with version 2.2.0, Samba has Linux support for extensions to
the name service switch infrastructure so Linux clients will
be able to obtain resolution of MS Windows NetBIOS names to IP
addresses. To gain this functionality, Samba needs to be compiled
with appropriate arguments to the make command (i.e., <strong class="userinput"><code>make
nsswitch/libnss_wins.so</code></strong>). The resulting library should
then be installed in the <code class="filename">/lib</code> directory, and
the <em class="parameter"><code>wins</code></em> parameter needs to be added to the “<span class="quote">hosts:</span>” line in
the <code class="filename">/etc/nsswitch.conf</code> file. At this point, it
will be possible to ping any MS Windows machine by its NetBIOS
machine name, as long as that machine is within the workgroup to
which both the Samba machine and the MS Windows machine belong.
</p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id425298"></a>Name Resolution as Used within MS Windows Networking</h2></div></div></div><p>
<a class="indexterm" name="id425306"></a>
<a class="indexterm" name="id425313"></a>
<a class="indexterm" name="id425320"></a>
<a class="indexterm" name="id425326"></a>
MS Windows networking is predicated on the name each machine is given. This name is known variously (and
inconsistently) as the “<span class="quote">computer name,</span>” “<span class="quote">machine name,</span>” “<span class="quote">networking
name,</span>” “<span class="quote">NetBIOS name,</span>” or “<span class="quote">SMB name.</span>” All terms mean the same thing with the
exception of “<span class="quote">NetBIOS name,</span>” which can also apply to the name of the workgroup or the domain
name. The terms “<span class="quote">workgroup</span>” and “<span class="quote">domain</span>” are really just a simple name with which
the machine is associated. All NetBIOS names are exactly 16 characters in length. The
16<sup>th</sup> character is reserved. It is used to store a 1-byte value that indicates
service level information for the NetBIOS name that is registered. A NetBIOS machine name is therefore
registered for each service type that is provided by the client/server.
</p><p>
<a href="integrate-ms-networks.html#uniqnetbiosnames" title="Table 29.1. Unique NetBIOS Names">Unique NetBIOS names</a> and <a href="integrate-ms-networks.html#netbiosnamesgrp" title="Table 29.2. Group Names">group names</a> tables
list typical NetBIOS name/service type registrations.
</p><div class="table"><a name="uniqnetbiosnames"></a><p class="title"><b>Table 29.1. Unique NetBIOS Names</b></p><div class="table-contents"><table summary="Unique NetBIOS Names" border="1"><colgroup><col align="left"><col align="justify"></colgroup><tbody><tr><td align="left">MACHINENAME<00></td><td align="justify">Server Service is running on MACHINENAME</td></tr><tr><td align="left">MACHINENAME<03></td><td align="justify">Generic machine name (NetBIOS name)</td></tr><tr><td align="left">MACHINENAME<20></td><td align="justify">LanMan server service is running on MACHINENAME</td></tr><tr><td align="left">WORKGROUP<1b></td><td align="justify">Domain master browser</td></tr></tbody></table></div></div><br class="table-break"><div class="table"><a name="netbiosnamesgrp"></a><p class="title"><b>Table 29.2. Group Names</b></p><div class="table-contents"><table summary="Group Names" border="1"><colgroup><col align="left"><col align="justify"></colgroup><tbody><tr><td align="left">WORKGROUP<03></td><td align="justify">Generic name registered by all members of WORKGROUP</td></tr><tr><td align="left">WORKGROUP<1c></td><td align="justify">Domain cntrollers/netlogon servers</td></tr><tr><td align="left">WORKGROUP<1d></td><td align="justify">Local master browsers</td></tr><tr><td align="left">WORKGROUP<1e></td><td align="justify">Browser election service</td></tr></tbody></table></div></div><br class="table-break"><p>
<a class="indexterm" name="id425508"></a>
It should be noted that all NetBIOS machines register their own
names as per <a href="integrate-ms-networks.html#uniqnetbiosnames" title="Table 29.1. Unique NetBIOS Names">Unique NetBIOS names</a> and <a href="integrate-ms-networks.html#netbiosnamesgrp" title="Table 29.2. Group Names">group names</a>. This is in vast contrast to TCP/IP
installations where the system administrator traditionally
determines in the <code class="filename">/etc/hosts</code> or in the DNS database what names
are associated with each IP address.
</p><p>
<a class="indexterm" name="id425540"></a>
<a class="indexterm" name="id425546"></a>
<a class="indexterm" name="id425553"></a>
One further point of clarification should be noted. The <code class="filename">/etc/hosts</code>
file and the DNS records do not provide the NetBIOS name information
that MS Windows clients depend on to locate the type of service that may
be needed. An example of this is what happens when an MS Windows client
wants to locate a domain logon server. It finds this service and the IP
address of a server that provides it by performing a lookup (via a
NetBIOS broadcast) for enumeration of all machines that have
registered the name type *<1C>. A logon request is then sent to each
IP address that is returned in the enumerated list of IP addresses.
Whichever machine first replies, it then ends up providing the logon services.
</p><p>
<a class="indexterm" name="id425577"></a>
<a class="indexterm" name="id425584"></a>
The name “<span class="quote">workgroup</span>” or “<span class="quote">domain</span>” really can be confusing, since these
have the added significance of indicating what is the security
architecture of the MS Windows network. The term “<span class="quote">workgroup</span>” indicates
that the primary nature of the network environment is that of a
peer-to-peer design. In a workgroup, all machines are responsible for
their own security, and generally such security is limited to the use of
just a password (known as share-level security). In most situations
with peer-to-peer networking, the users who control their own machines
will simply opt to have no security at all. It is possible to have
user-level security in a workgroup environment, thus requiring the use
of a username and a matching password.
</p><p>
<a class="indexterm" name="id425611"></a>
<a class="indexterm" name="id425618"></a>
<a class="indexterm" name="id425627"></a>
<a class="indexterm" name="id425636"></a>
<a class="indexterm" name="id425645"></a>
<a class="indexterm" name="id425654"></a>
<a class="indexterm" name="id425661"></a>
<a class="indexterm" name="id425668"></a>
MS Windows networking is thus predetermined to use machine names
for all local and remote machine message passing. The protocol used is
called Server Message Block (SMB), and this is implemented using
the NetBIOS protocol (Network Basic Input/Output System). NetBIOS can
be encapsulated using LLC (Logical Link Control) protocol in which case
the resulting protocol is called NetBEUI (Network Basic Extended User
Interface). NetBIOS can also be run over IPX (Internetworking Packet
Exchange) protocol as used by Novell NetWare, and it can be run
over TCP/IP protocols in which case the resulting protocol is called
NBT or NetBT, the NetBIOS over TCP/IP.
</p><p>
MS Windows machines use a complex array of name resolution mechanisms.
Since we are primarily concerned with TCP/IP, this demonstration is
limited to this area.
</p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id425691"></a>The NetBIOS Name Cache</h3></div></div></div><p>
<a class="indexterm" name="id425699"></a>
<a class="indexterm" name="id425706"></a>
<a class="indexterm" name="id425712"></a>
All MS Windows machines employ an in-memory buffer in which is
stored the NetBIOS names and IP addresses for all external
machines that machine has communicated with over the
past 10 to 15 minutes. It is more efficient to obtain an IP address
for a machine from the local cache than it is to go through all the
configured name resolution mechanisms.
</p><p>
<a class="indexterm" name="id425724"></a>
If a machine whose name is in the local name cache is shut
down before the name is expired and flushed from the cache, then
an attempt to exchange a message with that machine will be subject
to timeout delays. Its name is in the cache, so a name resolution
lookup will succeed, but the machine cannot respond. This can be
frustrating for users but is a characteristic of the protocol.
</p><p>
<a class="indexterm" name="id425737"></a>
<a class="indexterm" name="id425744"></a>
<a class="indexterm" name="id425751"></a>
The MS Windows utility that allows examination of the NetBIOS
name cache is called “<span class="quote">nbtstat.</span>” The Samba equivalent
is called <code class="literal">nmblookup</code>.
</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id425770"></a>The LMHOSTS File</h3></div></div></div><p>
<a class="indexterm" name="id425778"></a>
This file is usually located in MS Windows NT 4.0 or Windows 200x/XP in the directory
<code class="filename">%SystemRoot%\SYSTEM32\DRIVERS\ETC</code> and contains the IP address
and the machine name in matched pairs. The <code class="filename">LMHOSTS</code> file
performs NetBIOS name to IP address mapping.
</p><p>
It typically looks like this:
</p><pre class="programlisting">
# Copyright (c) 1998 Microsoft Corp.
#
# This is a sample LMHOSTS file used by the Microsoft Wins Client (NetBIOS
# over TCP/IP) stack for Windows98
#
# This file contains the mappings of IP addresses to NT computer names
# (NetBIOS) names. Each entry should be kept on an individual line.
# The IP address should be placed in the first column followed by the
# corresponding computer name. The address and the computer name
# should be separated by at least one space or tab. The "#" character
# is generally used to denote the start of a comment (see the exceptions
# below).
#
# This file is compatible with Microsoft LAN Manager 2.x TCP/IP lmhosts
# files and offers the following extensions:
#
# #PRE
# #DOM:<domain>
# #INCLUDE <filename>
# #BEGIN_ALTERNATE
# #END_ALTERNATE
# \0xnn (non-printing character support)
#
# Following any entry in the file with the characters "#PRE" will cause
# the entry to be preloaded into the name cache. By default, entries are
# not preloaded, but are parsed only after dynamic name resolution fails.
#
# Following an entry with the "#DOM:<domain>" tag will associate the
# entry with the domain specified by <domain>. This effects how the
# browser and logon services behave in TCP/IP environments. To preload
# the host name associated with #DOM entry, it is necessary to also add a
# #PRE to the line. The <domain> is always pre-loaded although it will not
# be shown when the name cache is viewed.
#
# Specifying "#INCLUDE <filename>" will force the RFC NetBIOS (NBT)
# software to seek the specified <filename> and parse it as if it were
# local. <filename> is generally a UNC-based name, allowing a
# centralized lmhosts file to be maintained on a server.
# It is ALWAYS necessary to provide a mapping for the IP address of the
# server prior to the #INCLUDE. This mapping must use the #PRE directive.
# In addition the share "public" in the example below must be in the
# LanMan Server list of "NullSessionShares" in order for client machines to
# be able to read the lmhosts file successfully. This key is under
# \machine\system\currentcontrolset\services\lanmanserver\
# parameters\nullsessionshares
# in the registry. Simply add "public" to the list found there.
#
# The #BEGIN_ and #END_ALTERNATE keywords allow multiple #INCLUDE
# statements to be grouped together. Any single successful include
# will cause the group to succeed.
#
# Finally, non-printing characters can be embedded in mappings by
# first surrounding the NetBIOS name in quotations, then using the
# \0xnn notation to specify a hex value for a non-printing character.
#
# The following example illustrates all of these extensions:
#
# 102.54.94.97 rhino #PRE #DOM:networking #net group's DC
# 102.54.94.102 "appname \0x14" #special app server
# 102.54.94.123 popular #PRE #source server
# 102.54.94.117 localsrv #PRE #needed for the include
#
# #BEGIN_ALTERNATE
# #INCLUDE \\localsrv\public\lmhosts
# #INCLUDE \\rhino\public\lmhosts
# #END_ALTERNATE
#
# In the above example, the "appname" server contains a special
# character in its name, the "popular" and "localsrv" server names are
# pre-loaded, and the "rhino" server name is specified so it can be used
# to later #INCLUDE a centrally maintained lmhosts file if the "localsrv"
# system is unavailable.
#
# Note that the whole file is parsed including comments on each lookup,
# so keeping the number of comments to a minimum will improve performance.
# Therefore it is not advisable to simply add lmhosts file entries onto the
# end of this file.
</pre></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id425896"></a>HOSTS File</h3></div></div></div><p>
This file is usually located in MS Windows NT 4.0 or Windows 200x/XP in
the directory <code class="filename">%SystemRoot%\SYSTEM32\DRIVERS\ETC</code> and contains
the IP address and the IP hostname in matched pairs. It can be
used by the name resolution infrastructure in MS Windows, depending
on how the TCP/IP environment is configured. This file is in
every way the equivalent of the UNIX/Linux <code class="filename">/etc/hosts</code> file.
</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id425921"></a>DNS Lookup</h3></div></div></div><p>
<a class="indexterm" name="id425928"></a>
This capability is configured in the TCP/IP setup area in the network
configuration facility. If enabled, an elaborate name resolution sequence
is followed, the precise nature of which is dependent on how the NetBIOS
Node Type parameter is configured. A Node Type of 0 means that
NetBIOS broadcast (over UDP broadcast) is used if the name
that is the subject of a name lookup is not found in the NetBIOS name
cache. If that fails, then DNS, HOSTS, and LMHOSTS are checked. If set to
Node Type 8, then a NetBIOS Unicast (over UDP Unicast) is sent to the
WINS server to obtain a lookup before DNS, HOSTS, LMHOSTS, or broadcast
lookup is used.
</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id425943"></a>WINS Lookup</h3></div></div></div><p>
<a class="indexterm" name="id425950"></a>
<a class="indexterm" name="id425957"></a>
<a class="indexterm" name="id425967"></a>
A WINS (Windows Internet Name Server) service is the equivalent of the
rfc1001/1002 specified NBNS (NetBIOS Name Server). A WINS server stores
the names and IP addresses that are registered by a Windows client
if the TCP/IP setup has been given at least one WINS server IP address.
</p><p>
To configure Samba to be a WINS server, the following parameter needs
to be added to the <code class="filename">smb.conf</code> file:
</p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id425996"></a><em class="parameter"><code>wins support = Yes</code></em></td></tr></table><p>
<a class="indexterm" name="id426011"></a>
To configure Samba to use a WINS server, the following parameters are
needed in the <code class="filename">smb.conf</code> file:
</p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id426032"></a><em class="parameter"><code>wins support = No</code></em></td></tr><tr><td><a class="indexterm" name="id426044"></a><em class="parameter"><code>wins server = xxx.xxx.xxx.xxx</code></em></td></tr></table><p>
where <em class="replaceable"><code>xxx.xxx.xxx.xxx</code></em> is the IP address
of the WINS server.
</p><p>For information about setting up Samba as a WINS server, read
<a href="NetworkBrowsing.html" title="Chapter 10. Network Browsing">Network Browsing</a>.</p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id426077"></a>Common Errors</h2></div></div></div><p>
TCP/IP network configuration problems find every network administrator sooner or later.
The cause can be anything from keyboard mishaps to forgetfulness to simple mistakes to
carelessness. Of course, no one is ever deliberately careless!
</p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id426088"></a>Pinging Works Only One Way</h3></div></div></div><p>
“<span class="quote">I can ping my Samba server from Windows, but I cannot ping my Windows
machine from the Samba server.</span>”
</p><p>
The Windows machine was at IP address 192.168.1.2 with netmask 255.255.255.0, the
Samba server (Linux) was at IP address 192.168.1.130 with netmask 255.255.255.128.
The machines were on a local network with no external connections.
</p><p>
Due to inconsistent netmasks, the Windows machine was on network 192.168.1.0/24, while
the Samba server was on network 192.168.1.128/25 logically a different network.
</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id426116"></a>Very Slow Network Connections</h3></div></div></div><p>
A common cause of slow network response includes:
</p><div class="itemizedlist"><ul type="disc"><li><p>Client is configured to use DNS and the DNS server is down.</p></li><li><p>Client is configured to use remote DNS server, but the
remote connection is down.</p></li><li><p>Client is configured to use a WINS server, but there is no WINS server.</p></li><li><p>Client is not configured to use a WINS server, but there is a WINS server.</p></li><li><p>Firewall is filtering out DNS or WINS traffic.</p></li></ul></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id426154"></a>Samba Server Name-Change Problem</h3></div></div></div><p>
“<span class="quote">The name of the Samba server was changed, Samba was restarted, and now the Samba server cannot be
pinged by its new name from an MS Windows NT4 workstation, but it does still respond to pinging using
the old name. Why?</span>”
</p><p>
From this description, three things are obvious:
</p><div class="itemizedlist"><ul type="disc"><li><p>WINS is not in use; only broadcast-based name resolution is used.</p></li><li><p>The Samba server was renamed and restarted within the last 10 or 15 minutes.</p></li><li><p>The old Samba server name is still in the NetBIOS name cache on the MS Windows NT4 workstation.</p></li></ul></div><p>
To find what names are present in the NetBIOS name cache on the MS Windows NT4 machine,
open a <code class="literal">cmd</code> shell and then:
</p><p>
</p><pre class="screen">
<code class="prompt">C:\> </code><strong class="userinput"><code>nbtstat -n</code></strong>
NetBIOS Local Name Table
Name Type Status
------------------------------------------------
FRODO <03> UNIQUE Registered
ADMINISTRATOR <03> UNIQUE Registered
FRODO <00> UNIQUE Registered
SARDON <00> GROUP Registered
FRODO <20> UNIQUE Registered
FRODO <1F> UNIQUE Registered
<code class="prompt">C:\> </code>nbtstat -c
NetBIOS Remote Cache Name Table
Name Type Host Address Life [sec]
--------------------------------------------------------------
GANDALF <20> UNIQUE 192.168.1.1 240
<code class="prompt">C:\> </code>
</pre><p>
</p><p>
In this example, GANDALF is the Samba server and FRODO is the MS Windows NT4 workstation.
The first listing shows the contents of the Local Name Table (i.e., identity information on
the MS Windows workstation), and the second shows the NetBIOS name in the NetBIOS name cache.
The name cache contains the remote machines known to this workstation.
</p></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="pam.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="optional.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="unicode.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 28. PAM-Based Distributed Authentication </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 30. Unicode/Charsets</td></tr></table></div></body></html>