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1 <html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Chapter 10. Network Browsing</title><link rel="stylesheet" href="samba.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.70.1"><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="ChangeNotes.html" title="Chapter 9. Important Samba-3.0.23 Change Notes"><link rel="next" href="passdb.html" title="Chapter 11. Account Information Databases"></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 10. Network Browsing</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ChangeNotes.html">Prev</a> </td><th width="60%" align="center">Part III. Advanced Configuration</th><td width="20%" align="right"> <a accesskey="n" href="passdb.html">Next</a></td></tr></table><hr></div><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="NetworkBrowsing"></a>Chapter 10. Network Browsing</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><div class="author"><h3 class="author"><span class="firstname">Jelmer</span> <span class="othername">R.</span> <span class="surname">Vernooij</span></h3><div class="affiliation"><span class="orgname">The Samba Team<br></span><div class="address"><p><code class="email"><<a href="mailto:jelmer@samba.org">jelmer@samba.org</a>></code></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">Jonathan</span> <span class="surname">Johnson</span></h3><div class="affiliation"><span class="orgname">Sutinen Consulting, Inc.<br></span><div class="address"><p><code class="email"><<a href="mailto:jon@sutinen.com">jon@sutinen.com</a>></code></p></div></div></div></div><div><p class="pubdate">July 5, 1998</p></div><div><p class="pubdate">Updated: September 20, 2006</p></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="sect1"><a href="NetworkBrowsing.html#id2583396">Features and Benefits</a></span></dt><dt><span class="sect1"><a href="NetworkBrowsing.html#id2583585">What Is Browsing?</a></span></dt><dt><span class="sect1"><a href="NetworkBrowsing.html#netdiscuss">Discussion</a></span></dt><dd><dl><dt><span class="sect2"><a href="NetworkBrowsing.html#id2583968">NetBIOS over TCP/IP</a></span></dt><dt><span class="sect2"><a href="NetworkBrowsing.html#id2584571">TCP/IP without NetBIOS</a></span></dt><dt><span class="sect2"><a href="NetworkBrowsing.html#adsdnstech">DNS and Active Directory</a></span></dt></dl></dd><dt><span class="sect1"><a href="NetworkBrowsing.html#id2585130">How Browsing Functions</a></span></dt><dd><dl><dt><span class="sect2"><a href="NetworkBrowsing.html#DMB">Configuring Workgroup Browsing</a></span></dt><dt><span class="sect2"><a href="NetworkBrowsing.html#id2586055">Domain Browsing Configuration</a></span></dt><dt><span class="sect2"><a href="NetworkBrowsing.html#browse-force-master">Forcing Samba to Be the Master</a></span></dt><dt><span class="sect2"><a href="NetworkBrowsing.html#id2586621">Making Samba the Domain Master</a></span></dt><dt><span class="sect2"><a href="NetworkBrowsing.html#id2586849">Note about Broadcast Addresses</a></span></dt><dt><span class="sect2"><a href="NetworkBrowsing.html#id2586871">Multiple Interfaces</a></span></dt><dt><span class="sect2"><a href="NetworkBrowsing.html#id2587048">Use of the Remote Announce Parameter</a></span></dt><dt><span class="sect2"><a href="NetworkBrowsing.html#id2587183">Use of the Remote Browse Sync Parameter</a></span></dt></dl></dd><dt><span class="sect1"><a href="NetworkBrowsing.html#id2587274">WINS: The Windows Internetworking Name Server</a></span></dt><dd><dl><dt><span class="sect2"><a href="NetworkBrowsing.html#id2587530">WINS Server Configuration</a></span></dt><dt><span class="sect2"><a href="NetworkBrowsing.html#id2587836">WINS Replication</a></span></dt><dt><span class="sect2"><a href="NetworkBrowsing.html#id2587890">Static WINS Entries</a></span></dt></dl></dd><dt><span class="sect1"><a href="NetworkBrowsing.html#id2588121">Helpful Hints</a></span></dt><dd><dl><dt><span class="sect2"><a href="NetworkBrowsing.html#id2588132">Windows Networking Protocols</a></span></dt><dt><span class="sect2"><a href="NetworkBrowsing.html#id2588278">Name Resolution Order</a></span></dt></dl></dd><dt><span class="sect1"><a href="NetworkBrowsing.html#id2588485">Technical Overview of Browsing</a></span></dt><dd><dl><dt><span class="sect2"><a href="NetworkBrowsing.html#id2588567">Browsing Support in Samba</a></span></dt><dt><span class="sect2"><a href="NetworkBrowsing.html#id2588756">Problem Resolution</a></span></dt><dt><span class="sect2"><a href="NetworkBrowsing.html#id2588995">Cross-Subnet Browsing</a></span></dt></dl></dd><dt><span class="sect1"><a href="NetworkBrowsing.html#id2590010">Common Errors</a></span></dt><dd><dl><dt><span class="sect2"><a href="NetworkBrowsing.html#id2590036">Flushing the Samba NetBIOS Name Cache</a></span></dt><dt><span class="sect2"><a href="NetworkBrowsing.html#id2590109">Server Resources Cannot Be Listed</a></span></dt><dt><span class="sect2"><a href="NetworkBrowsing.html#id2590153">I Get an "<span class="errorname">Unable to browse the network</span>" Error</a></span></dt><dt><span class="sect2"><a href="NetworkBrowsing.html#id2590200">Browsing of Shares and Directories is Very Slow</a></span></dt><dt><span class="sect2"><a href="NetworkBrowsing.html#id2590401">Invalid Cached Share References Affects Network Browsing</a></span></dt></dl></dd></dl></div><p>
6 This chapter contains detailed information as well as a fast-track guide to
7 implementing browsing across subnets and/or across workgroups (or domains).
8 WINS is the best tool for resolution of NetBIOS names to IP addresses; however, WINS is
9 not involved in browse list handling except by way of name-to-address resolution.
10 </p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
12 What is WINS?
13 </p><p>
14 WINS is a facility that provides resolution of a NetBIOS name to its IP address. WINS is like a
15 Dynamic-DNS service for NetBIOS networking names.
16 </p></div><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
21 MS Windows 2000 and later versions can be configured to operate with no NetBIOS
22 over TCP/IP. Samba-3 and later versions also support this mode of operation.
23 When the use of NetBIOS over TCP/IP has been disabled, the primary
24 means for resolution of MS Windows machine names is via DNS and Active Directory.
25 The following information assumes that your site is running NetBIOS over TCP/IP.
26 </p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2583396"></a>Features and Benefits</h2></div></div></div><p>
27 Charles Dickens once referred to the past in these words: “<span class="quote"><span class="emphasis"><em>It was the best of times,
28 it was the worst of times.</em></span></span>” The more we look back, the more we long for what was and
29 hope it never returns.
30 </p><p>
34 For many MS Windows network administrators, that statement sums up their feelings about
35 NetBIOS networking precisely. For those who mastered NetBIOS networking, its fickle
36 nature was just par for the course. For those who never quite managed to tame its
37 lusty features, NetBIOS is like Paterson's Curse.
38 </p><p>
39 For those not familiar with botanical problems in Australia, Paterson's Curse,
40 <span class="emphasis"><em>Echium plantagineum</em></span>, was introduced to Australia from Europe during the mid-19th
41 century. Since then it has spread rapidly. The high seed production, with densities of
42 thousands of seeds per square meter, a seed longevity of more than 7 years, and an
43 ability to germinate at any time of year, given the right conditions, are some of the
44 features that make it such a persistent weed.
45 </p><p>
51 In this chapter we explore vital aspects of Server Message Block (SMB) networking with
52 a particular focus on SMB as implemented through running NetBIOS (Network Basic
53 Input/Output System) over TCP/IP. Since Samba does not implement SMB or NetBIOS over
54 any other protocols, we need to know how to configure our network environment and simply
55 remember to use nothing but TCP/IP on all our MS Windows network clients.
56 </p><p>
59 Samba provides the ability to implement a WINS (Windows Internetworking Name Server)
60 and implements extensions to Microsoft's implementation of WINS. These extensions
61 help Samba to effect stable WINS operations beyond the normal scope of MS WINS.
62 </p><p>
66 WINS is exclusively a service that applies only to those systems
67 that run NetBIOS over TCP/IP. MS Windows 200x/XP have the capacity to operate with
68 support for NetBIOS disabled, in which case WINS is of no relevance. Samba supports this also.
69 </p><p>
73 For those networks on which NetBIOS has been disabled (i.e., WINS is not required),
74 the use of DNS is necessary for hostname resolution.
75 </p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2583585"></a>What Is Browsing?</h2></div></div></div><p>
80 To most people, browsing means they can see the MS Windows and Samba servers
81 in the Network Neighborhood, and when the computer icon for a particular server is
82 clicked, it opens up and shows the shares and printers available on the target server.
83 </p><p>
84 What seems so simple is in fact a complex interaction of different technologies.
85 The technologies (or methods) employed in making all of this work include:
86 </p><div class="itemizedlist"><ul type="disc"><li><p>MS Windows machines register their presence to the network.</p></li><li><p>Machines announce themselves to other machines on the network.</p></li><li><p>One or more machines on the network collate the local announcements.</p></li><li><p>The client machine finds the machine that has the collated list of machines.</p></li><li><p>The client machine is able to resolve the machine names to IP addresses.</p></li><li><p>The client machine is able to connect to a target machine.</p></li></ul></div><p>
90 The Samba application that controls browse list management and name resolution is
91 called <code class="filename">nmbd</code>. The configuration parameters involved in nmbd's operation are:
92 </p><p>
93 Browsing options:
94 </p><div class="itemizedlist"><ul type="disc"><li><a class="indexterm" name="id2583707"></a>os level</li><li><a class="indexterm" name="id2583716"></a>lm announce</li><li><a class="indexterm" name="id2583726"></a>lm interval</li><li><a class="indexterm" name="id2583735"></a>preferred master(*)</li><li><a class="indexterm" name="id2583744"></a>local master(*)</li><li><a class="indexterm" name="id2583754"></a>domain master(*)</li><li><a class="indexterm" name="id2583763"></a>browse list</li><li><a class="indexterm" name="id2583772"></a>enhanced browsing</li></ul></div><p>
95 Name Resolution Method:
96 </p><div class="itemizedlist"><ul type="disc"><li><a class="indexterm" name="id2583789"></a>name resolve order(*)</li></ul></div><p>
97 WINS options:
98 </p><div class="itemizedlist"><ul type="disc"><li><a class="indexterm" name="id2583805"></a>dns proxy</li><li><a class="indexterm" name="id2583814"></a>wins proxy</li><li><a class="indexterm" name="id2583824"></a>wins server(*)</li><li><a class="indexterm" name="id2583833"></a>wins support(*)</li><li><a class="indexterm" name="id2583842"></a>wins hook</li></ul></div><p>
99 Those marked with an (*) are the only options that commonly may need to be modified. Even if none of these
101 </p><p>
107 For Samba, the WINS Server and WINS Support are mutually exclusive options. When <span><strong class="command">nmbd</strong></span> is
108 started it will fail to execute if both options are set in the <code class="filename">smb.conf</code> file. The <span><strong class="command">nmbd</strong></span>
109 understands that when it spawns an instance of itself to run as a WINS server that it has to use its own WINS
110 server also.
111 </p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="netdiscuss"></a>Discussion</h2></div></div></div><p>
116 All MS Windows networking uses SMB-based messaging. SMB messaging may be implemented with or without NetBIOS.
117 MS Windows 200x supports NetBIOS over TCP/IP for backwards compatibility. Microsoft appears intent on phasing
118 out NetBIOS support.
119 </p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2583968"></a>NetBIOS over TCP/IP</h3></div></div></div><p>
124 Samba implements NetBIOS, as does MS Windows NT/200x/XP, by encapsulating it over TCP/IP.
125 NetBIOS-based networking uses broadcast messaging to effect browse list management. When running NetBIOS over
126 TCP/IP, this uses UDP-based messaging. UDP messages can be broadcast or unicast.
127 </p><p>
129 Normally, only unicast UDP messaging can be forwarded by routers. The
130 <a class="indexterm" name="id2584019"></a>remote announce parameter to smb.conf helps to project browse announcements
131 to remote network segments via unicast UDP. Similarly, the
132 <a class="indexterm" name="id2584028"></a>remote browse sync parameter of <code class="filename">smb.conf</code>
133 implements browse list collation using unicast UDP.
134 </p><p>
135 The methods used by MS Windows to perform name lookup requests (name resolution) is determined by a
136 configuration parameter called the NetBIOS node-type. There are four basic NetBIOS node types:
137 </p><a class="indexterm" name="id2584050"></a><a class="indexterm" name="id2584057"></a><a class="indexterm" name="id2584064"></a><a class="indexterm" name="id2584070"></a><a class="indexterm" name="id2584077"></a><a class="indexterm" name="id2584084"></a><a class="indexterm" name="id2584091"></a><a class="indexterm" name="id2584098"></a><div class="itemizedlist"><ul type="disc"><li><p><span class="emphasis"><em>b-node (type 0x01):</em></span> The Windows client will use only
138 NetBIOS broadcast requests using UDP broadcast.</p></li><li><p><span class="emphasis"><em>p-node (type 0x02):</em></span> The Windows client will use point-to-point
139 (NetBIOS unicast) requests using UDP unicast directed to a WINS server.</p></li><li><p><span class="emphasis"><em>m-node (type 0x04):</em></span> The Windows client will first use
140 NetBIOS broadcast requests using UDP broadcast, then it will use (NetBIOS unicast)
141 requests using UDP unicast directed to a WINS server.</p></li><li><p><span class="emphasis"><em>h-node (type 0x08):</em></span> The Windows client will use
142 (NetBIOS unicast) requests using UDP unicast directed to a WINS server, then it will use
143 NetBIOS broadcast requests using UDP broadcast.</p></li></ul></div><p>
150 The default Windows network client (or server) network configuration enables NetBIOS over TCP/IP
151 and b-node configuration. The use of WINS makes most sense with h-node (hybrid mode) operation so that
152 in the event of a WINS breakdown or non-availability, the client can use broadcast-based name resolution.
153 </p><p>
161 In those networks where Samba is the only SMB server technology, wherever possible <code class="filename">nmbd</code>
162 should be configured on one machine as the WINS server. This makes it easy to manage the browsing environment.
163 If each network segment is configured with its own Samba WINS server, then the only way to get cross-segment
164 browsing to work is by using the <a class="indexterm" name="id2584258"></a>remote announce and the <a class="indexterm" name="id2584266"></a>remote browse sync parameters to your <code class="filename">smb.conf</code> file.
165 </p><p>
167 If only one WINS server is used for an entire multisegment network, then
169 <a class="indexterm" name="id2584299"></a>remote browse sync parameters should not be necessary.
170 </p><p>
172 As of Samba-3, WINS replication is being worked on. The bulk of the code has been committed, but it still
173 needs maturation. This is not a supported feature of the Samba-3.0.20 release. Hopefully, this will become a
174 supported feature of one of the Samba-3 release series. The delay is caused by the fact that this feature has
175 not been of sufficient significance to inspire someone to pay a developer to complete it.
176 </p><p>
185 Right now Samba WINS does not support MS-WINS replication. This means that when setting up Samba as a WINS
186 server, there must only be one <code class="filename">nmbd</code> configured as a WINS server on the network. Some
187 sites have used multiple Samba WINS servers for redundancy (one server per subnet) and then used
188 <a class="indexterm" name="id2584395"></a>remote browse sync and <a class="indexterm" name="id2584402"></a>remote announce to effect browse list
189 collation across all segments. Note that this means clients will only resolve local names and must be
190 configured to use DNS to resolve names on other subnets in order to resolve the IP addresses of the servers
191 they can see on other subnets. This setup is not recommended but is mentioned as a practical consideration
192 (i.e., an “<span class="quote">if all else fails</span>” scenario). NetBIOS over TCP/IP is an ugly and difficult to manage
193 protocol. Its replacement, NetBIOSless SMB over TCP/IP is not without its own manageability concerns. NetBIOS
194 based networking is a life of compromise and trade-offs. WINS stores information that cannot be stored in
195 DNS; consequently, DNS is a poor substitute for WINS given that when NetBIOS over TCP/IP is used, Windows
196 clients are designed to use WINS.
197 </p><p>
201 Lastly, take note that browse lists are a collection of unreliable broadcast
202 messages that are repeated at intervals of not more than 15 minutes. This means
203 that it will take time to establish a browse list, and it can take up to 45
204 minutes to stabilize, particularly across network segments.
205 </p><p>
207 When an MS Windows 200x/XP system attempts to resolve a host name to an IP address, it follows a defined path:
209 Checks the <code class="filename">hosts</code> file. It is located in <code class="filename">%SystemRoot%\System32\Drivers\etc</code>.
210 </p></li><li><p>
211 Does a DNS lookup.
212 </p></li><li><p>
213 Checks the NetBIOS name cache.
214 </p></li><li><p>
215 Queries the WINS server.
216 </p></li><li><p>
217 Does a broadcast name lookup over UDP.
218 </p></li><li><p>
219 Looks up entries in LMHOSTS, located in <code class="filename">%SystemRoot%\System32\Drivers\etc</code>.
220 </p></li></ol></div><p>
225 Given the nature of how the NetBIOS over TCP/IP protocol is implemented, only WINS is capable of resolving
226 with any reliability name lookups for service-oriented names such as TEMPTATION<1C> a NetBIOS
227 name query that seeks to find network logon servers. DNS has no concept of service-oriented names such as
228 this. In fact, the Microsoft ADS implementation specifically manages a whole range of extended
229 service-oriented DNS entries. This type of facility is not implemented and is not supported for the NetBIOS
230 over TCP/IP protocol namespace.
231 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2584571"></a>TCP/IP without NetBIOS</h3></div></div></div><p>
235 All TCP/IP-enabled systems use various forms of hostname resolution. The primary
236 methods for TCP/IP hostname resolution involve either a static file (<code class="filename">/etc/hosts</code>)
237 or the Domain Name System (DNS). DNS is the technology that makes
238 the Internet usable. DNS-based hostname resolution is supported by nearly all
239 TCP/IP-enabled systems. Only a few embedded TCP/IP systems do not support DNS.
240 </p><p>
245 Windows 200x/XP can register its hostname with a Dynamic DNS server (DDNS). It is possible to force register with a
246 dynamic DNS server in Windows 200x/XP using <span><strong class="command">ipconfig /registerdns</strong></span>.
247 </p><p>
251 With Active Directory, a correctly functioning DNS server is absolutely essential. In the absence of a working
252 DNS server that has been correctly configured, MS Windows clients and servers will be unable to locate each
253 other, so network services consequently will be severely impaired.
254 </p><p>
261 Use of raw SMB over TCP/IP (No NetBIOS layer) can be done only with Active Directory domains. Samba is not an
262 Active Directory domain controller: ergo, it is not possible to run Samba as a domain controller and at the same
263 time <span class="emphasis"><em>not</em></span> use NetBIOS. Where Samba is used as an Active Directory domain member server
264 (DMS) it is possible to configure Samba to not use NetBIOS over TCP/IP. A Samba DMS can integrate fully into
265 an Active Directory domain, however, if NetBIOS over TCP/IP is disabled, it is necessary to manually create
266 appropriate DNS entries for the Samba DMS because they will not be automatically generated either by Samba, or
267 by the ADS environment.
268 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="adsdnstech"></a>DNS and Active Directory</h3></div></div></div><p>
274 Occasionally we hear from UNIX network administrators who want to use a UNIX-based DDNS server in place
275 of the Microsoft DNS server. While this might be desirable to some, the MS Windows 200x DNS server is
276 autoconfigured to work with Active Directory. It is possible to use BIND version 8 or 9, but it will almost
277 certainly be necessary to create service records (SRV records) so MS Active Directory clients can resolve
278 hostnames to locate essential network services. The following are some of the default service records that
279 Active Directory requires:
280 </p><p>
284 The use of DDNS is highly recommended with Active Directory, in which case the use of BIND9 is preferred for
285 its ability to adequately support the SRV (service) records that are needed for Active Directory. Of course,
286 when running ADS, it makes sense to use Microsoft's own DDNS server because of the natural affinity between ADS
287 and MS DNS.
288 </p><div class="variablelist"><dl><dt><span class="term">_ldap._tcp.pdc._msdcs.<span class="emphasis"><em>Domain</em></span></span></dt><dd><p>
289 This provides the address of the Windows NT PDC for the domain.
290 </p></dd><dt><span class="term">_ldap._tcp.pdc._msdcs.<span class="emphasis"><em>DomainTree</em></span></span></dt><dd><p>
291 Resolves the addresses of global catalog servers in the domain.
292 </p></dd><dt><span class="term">_ldap._tcp.<span class="emphasis"><em>site</em></span>.sites.writable._msdcs.<span class="emphasis"><em>Domain</em></span></span></dt><dd><p>
293 Provides list of domain controllers based on sites.
294 </p></dd><dt><span class="term">_ldap._tcp.writable._msdcs.<span class="emphasis"><em>Domain</em></span></span></dt><dd><p>
295 Enumerates list of domain controllers that have the writable copies of the Active Directory data store.
296 </p></dd><dt><span class="term">_ldap._tcp.<span class="emphasis"><em>GUID</em></span>.domains._msdcs.<span class="emphasis"><em>DomainTree</em></span></span></dt><dd><p>
297 Entry used by MS Windows clients to locate machines using the global unique identifier.
298 </p></dd><dt><span class="term">_ldap._tcp.<span class="emphasis"><em>Site</em></span>.gc._msdcs.<span class="emphasis"><em>DomainTree</em></span></span></dt><dd><p>
299 Used by Microsoft Windows clients to locate the site configuration-dependent global catalog server.
300 </p></dd></dl></div><p>
301 Specific entries used by Microsoft clients to locate essential services for an example domain
304 _kerberos._udp.quenya.org Used to contact the KDC server via UDP.
305 This entry must list port 88 for each KDC.
306 </p></li><li><p>
308 when a user password change must be processed. This record must list port 464 on the
309 master KDC.
310 </p></li><li><p>
311 _kerberos._tcp.quenya.org Used to locate the KDC server via TCP.
312 This entry must list port 88 for each KDC.
313 </p></li><li><p>
314 _ldap._tcp.quenya.org Used to locate the LDAP service on the PDC.
315 This record must list port 389 for the PDC.
316 </p></li><li><p>
318 to permit user password changes to be processed. This must list port 464.
319 </p></li><li><p>
320 _gc._tcp.quenya.org Used to locate the global catalog server for the
321 top of the domain. This must list port 3268.
322 </p></li></ul></div><p>
323 The following records are also used by the Windows domain member client to locate vital
324 services on the Windows ADS domain controllers.
326 _ldap._tcp.pdc._msdcs.quenya.org
327 </p></li><li><p>
328 _ldap.gc._msdcs.quenya.org
329 </p></li><li><p>
330 _ldap.default-first-site-name._sites.gc._msdcs.quenya.org
331 </p></li><li><p>
332 _ldap.{SecID}.domains._msdcs.quenya.org
333 </p></li><li><p>
334 _ldap._tcp.dc._msdcs.quenya.org
335 </p></li><li><p>
336 _kerberos._tcp.dc._msdcs.quenya.org
337 </p></li><li><p>
338 _ldap.default-first-site-name._sites.dc._msdcs.quenya.org
339 </p></li><li><p>
340 _kerberos.default-first-site-name._sites.dc._msdcs.queyna.org
341 </p></li><li><p>
342 SecID._msdcs.quenya.org
343 </p></li></ul></div><p>
344 Presence of the correct DNS entries can be validated by executing:
349 ;; global options: printcmd
350 ;; Got answer:
355 ;; QUESTION SECTION:
356 ;_ldap._tcp.dc._msdcs.quenya.org. IN ANY
359 ;; ANSWER SECTION:
364 ;; ADDITIONAL SECTION:
369 ;; Query time: 0 msec
372 ;; MSG SIZE rcvd: 171
373 </pre><p>
374 </p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2585130"></a>How Browsing Functions</h2></div></div></div><p>
380 MS Windows machines register their NetBIOS names (i.e., the machine name for each service type in operation)
381 on startup. The exact method by which this name registration takes place is determined by whether or not the
382 MS Windows client/server has been given a WINS server address, whether or not LMHOSTS lookup is enabled,
383 whether or not DNS for NetBIOS name resolution is enabled, and so on.
384 </p><p>
388 In the case where there is no WINS server, all name registrations as well as name lookups are done by UDP
389 broadcast. This isolates name resolution to the local subnet, unless LMHOSTS is used to list all names and IP
390 addresses. In such situations, Samba provides a means by which the Samba server name may be forcibly injected
391 into the browse list of a remote MS Windows network (using the <a class="indexterm" name="id2585209"></a>remote announce
392 parameter).
393 </p><p>
397 Where a WINS server is used, the MS Windows client will use UDP unicast to register with the WINS server. Such
398 packets can be routed, and thus WINS allows name resolution to function across routed networks.
399 </p><p>
408 During the startup process, an election takes place to create a local master browser (LMB) if one does not
409 already exist. On each NetBIOS network one machine will be elected to function as the domain master browser
410 (DMB). This domain browsing has nothing to do with MS security Domain Control. Instead, the DMB serves the
411 role of contacting each LMB (found by asking WINS or from LMHOSTS) and exchanging browse list contents. This
412 way every master browser will eventually obtain a complete list of all machines that are on the network. Every
413 11 to 15 minutes an election is held to determine which machine will be the master browser. By the nature of
414 the election criteria used, the machine with the highest uptime, or the most senior protocol version or other
415 criteria, will win the election as DMB.
416 </p><p>
425 Where a WINS server is used, the DMB registers its IP address with the WINS server using the name of the
426 domain and the NetBIOS name type 1B (e.g., DOMAIN<1B>). All LMBs register their IP addresses with the WINS
427 server, also with the name of the domain and the NetBIOS name type of 1D. The 1B name is unique to one
428 server within the domain security context, and only one 1D name is registered for each network segment.
429 Machines that have registered the 1D name will be authoritive browse list maintainers for the network segment
430 they are on. The DMB is responsible for synchronizing the browse lists it obtains from the LMBs.
431 </p><p>
433 Clients wishing to browse the network make use of this list but also depend on the availability of correct
434 name resolution to the respective IP address or addresses.
435 </p><p>
437 Any configuration that breaks name resolution and/or browsing intrinsics will annoy users because they will
438 have to put up with protracted inability to use the network services.
439 </p><p>
446 Samba supports a feature that allows forced synchronization of browse lists across routed networks using the
447 <a class="indexterm" name="id2585474"></a>remote browse sync parameter in the <code class="filename">smb.conf</code> file. This causes Samba to contact the
448 LMB on a remote network and to request browse list synchronization. This effectively bridges two networks that
449 are separated by routers. The two remote networks may use either broadcast-based name resolution or WINS-based
450 name resolution, but it should be noted that the <a class="indexterm" name="id2585493"></a>remote browse sync parameter provides
451 browse list synchronization and that is distinct from name-to-address resolution. In other words,
452 for cross-subnet browsing to function correctly, it is essential that a name-to-address resolution mechanism
453 be provided. This mechanism could be via DNS, <code class="filename">/etc/hosts</code>, and so on.
454 </p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="DMB"></a>Configuring Workgroup Browsing</h3></div></div></div><p>
461 To configure cross-subnet browsing on a network containing machines in a workgroup, not an NT domain, you need
462 to set up one Samba server to be the DMB (note that this is not the same as a Primary Domain Controller,
463 although in an NT domain the same machine plays both roles). The role of a DMB is to collate the browse lists
464 from LMB on all the subnets that have a machine participating in the workgroup. Without one machine configured
465 as a DMB, each subnet would be an isolated workgroup unable to see any machines on another subnet. It is the
466 presence of a DMB that makes cross-subnet browsing possible for a workgroup.
467 </p><p>
469 In a workgroup environment the DMB must be a Samba server, and there must only be one DMB per workgroup name.
470 To set up a Samba server as a DMB, set the following option in the <em class="parameter"><code>[global]</code></em> section
472 </p><p>
473 </p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id2585610"></a><em class="parameter"><code>domain master = yes</code></em></td></tr></table><p>
474 </p><p>
477 The DMB should preferably be the LMB for its own subnet. In order to achieve this, set the following options
478 in the <em class="parameter"><code>[global]</code></em> section of the <code class="filename">smb.conf</code> file as shown in <a href="NetworkBrowsing.html#dmbexample" title="Example 10.1. Domain Master Browser smb.conf">Domain Master Browser smb.conf</a>
479 </p><div class="example"><a name="dmbexample"></a><p class="title"><b>Example 10.1. Domain Master Browser smb.conf</b></p><div class="example-contents"><table class="simplelist" border="0" summary="Simple list"><tr><td> </td></tr><tr><td><em class="parameter"><code>[global]</code></em></td></tr><tr><td><a class="indexterm" name="id2585687"></a><em class="parameter"><code>domain master = yes</code></em></td></tr><tr><td><a class="indexterm" name="id2585700"></a><em class="parameter"><code>local master = yes</code></em></td></tr><tr><td><a class="indexterm" name="id2585713"></a><em class="parameter"><code>preferred master = yes</code></em></td></tr><tr><td><a class="indexterm" name="id2585726"></a><em class="parameter"><code>os level = 65</code></em></td></tr></table></div></div><br class="example-break"><p>
482 The DMB may be the same machine as the WINS server, if necessary.
483 </p><p>
487 Next, you should ensure that each of the subnets contains a machine that can act as an LMB for the workgroup.
488 Any MS Windows NT/200x/XP machine should be able to do this, as will Windows 9x/Me machines (although these
489 tend to get rebooted more often, so it is not such a good idea to use them). To make a Samba server an LMB,
490 set the following options in the <em class="parameter"><code>[global]</code></em> section of the <code class="filename">smb.conf</code> file as shown in
491 <a href="NetworkBrowsing.html#lmbexample" title="Example 10.2. Local master browser smb.conf">Local master browser smb.conf</a>
492 </p><div class="example"><a name="lmbexample"></a><p class="title"><b>Example 10.2. Local master browser smb.conf</b></p><div class="example-contents"><table class="simplelist" border="0" summary="Simple list"><tr><td> </td></tr><tr><td><em class="parameter"><code>[global]</code></em></td></tr><tr><td><a class="indexterm" name="id2585830"></a><em class="parameter"><code>domain master = no</code></em></td></tr><tr><td><a class="indexterm" name="id2585843"></a><em class="parameter"><code>local master = yes</code></em></td></tr><tr><td><a class="indexterm" name="id2585856"></a><em class="parameter"><code>preferred master = yes</code></em></td></tr><tr><td><a class="indexterm" name="id2585869"></a><em class="parameter"><code>os level = 65</code></em></td></tr></table></div></div><br class="example-break"><p>
494 Do not do this for more than one Samba server on each subnet, or they will war with
495 each other over which is to be the LMB.
496 </p><p>
500 LMB. The <a class="indexterm" name="id2585918"></a>preferred master causes <span><strong class="command">nmbd</strong></span>
501 to force a browser election on startup and the <a class="indexterm" name="id2585932"></a>os level
502 parameter sets Samba high enough so it should win any browser elections.
503 </p><p>
505 If you have an NT machine on the subnet that you wish to be the LMB, you can disable Samba from
506 becoming an LMB by setting the following options in the <em class="parameter"><code>[global]</code></em> section of the
507 <code class="filename">smb.conf</code> file as shown in <a href="NetworkBrowsing.html#nombexample" title="Example 10.3. smb.conf for Not Being a Master Browser">smb.conf for Not Being a Master Browser</a>.
508 </p><p>
509 </p><div class="example"><a name="nombexample"></a><p class="title"><b>Example 10.3. smb.conf for Not Being a Master Browser</b></p><div class="example-contents"><table class="simplelist" border="0" summary="Simple list"><tr><td> </td></tr><tr><td><em class="parameter"><code>[global]</code></em></td></tr><tr><td><a class="indexterm" name="id2586000"></a><em class="parameter"><code>domain master = no</code></em></td></tr><tr><td><a class="indexterm" name="id2586013"></a><em class="parameter"><code>local master = no</code></em></td></tr><tr><td><a class="indexterm" name="id2586026"></a><em class="parameter"><code>preferred master = no</code></em></td></tr><tr><td><a class="indexterm" name="id2586039"></a><em class="parameter"><code>os level = 0</code></em></td></tr></table></div></div><p><br class="example-break">
510 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2586055"></a>Domain Browsing Configuration</h3></div></div></div><p>
515 If you are adding Samba servers to a Windows NT domain, then you must not set up a Samba server as a DMB. By
516 default, a Windows NT PDC for a domain is also the DMB for that domain. Network browsing may break if a Samba
517 server other than the PDC registers the DMB NetBIOS name (<em class="replaceable"><code>DOMAIN</code></em><1B>) with
518 WINS.
519 </p><p>
521 For subnets other than the one containing the Windows NT PDC, you may set up Samba servers as LMBs as
522 described. To make a Samba server a Local Master Browser, set the following options in the <em class="parameter"><code>[global]</code></em> section of the <code class="filename">smb.conf</code> file as shown in <a href="NetworkBrowsing.html#remsmb" title="Example 10.4. Local Master Browser smb.conf">Local Master Browser
523 smb.conf</a>
524 </p><div class="example"><a name="remsmb"></a><p class="title"><b>Example 10.4. Local Master Browser smb.conf</b></p><div class="example-contents"><table class="simplelist" border="0" summary="Simple list"><tr><td> </td></tr><tr><td><em class="parameter"><code>[global]</code></em></td></tr><tr><td><a class="indexterm" name="id2586157"></a><em class="parameter"><code>domain master = no</code></em></td></tr><tr><td><a class="indexterm" name="id2586170"></a><em class="parameter"><code>local master = yes</code></em></td></tr><tr><td><a class="indexterm" name="id2586183"></a><em class="parameter"><code>preferred master = yes</code></em></td></tr><tr><td><a class="indexterm" name="id2586196"></a><em class="parameter"><code>os level = 65</code></em></td></tr></table></div></div><br class="example-break"><p>
527 If you wish to have a Samba server fight the election with machines on the same subnet, you may set the
528 <a class="indexterm" name="id2586227"></a>os level parameter to lower levels. By doing this you can tune the order of machines
529 that will become LMBs if they are running. For more details on this, refer to <a href="NetworkBrowsing.html#browse-force-master" title="Forcing Samba to Be the Master">Forcing Samba to Be the Master</a>.
530 </p><p>
534 If you have Windows NT machines that are members of the domain on all subnets and you are sure they will
535 always be running, you can disable Samba from taking part in browser elections and ever becoming an LMB by
536 setting the following options in the <em class="parameter"><code>[global]</code></em> section of the <code class="filename">smb.conf</code> file as shown
537 in <a href="NetworkBrowsing.html#xremmb" title="Example 10.5. smb.conf for Not Being a master browser"><code class="filename">smb.conf</code> for Not Being a master browser</a>
538 </p><p>
539 </p><div class="example"><a name="xremmb"></a><p class="title"><b>Example 10.5. <code class="filename">smb.conf</code> for Not Being a master browser</b></p><div class="example-contents"><em class="parameter"><code>[global]</code></em><a class="indexterm" name="id2586321"></a>domain master = no
544 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="browse-force-master"></a>Forcing Samba to Be the Master</h3></div></div></div><p>
552 Who becomes the master browser is determined by an election process using broadcasts. Each election packet
553 contains a number of parameters that determine what precedence (bias) a host should have in the election. By
554 default Samba uses a low precedence and thus loses elections to just about every Windows network server or
555 client.
556 </p><p>
557 If you want Samba to win elections, set the <a class="indexterm" name="id2586423"></a>os level global option in <code class="filename">smb.conf</code> to a
558 higher number. It defaults to 20. Using 34 would make it win all elections over every other system (except
559 other Samba systems).
560 </p><p>
561 An <a class="indexterm" name="id2586442"></a>os level of two would make it beat Windows for Workgroups and Windows 9x/Me, but
562 not MS Windows NT/200x Server. An MS Windows NT/200x Server domain controller uses level 32. The maximum os
563 level is 255.
564 </p><p>
569 If you want Samba to force an election on startup, set the <a class="indexterm" name="id2586484"></a>preferred master global
570 option in <code class="filename">smb.conf</code> to <code class="constant">yes</code>. Samba will then have a slight advantage over other
571 potential master browsers that are not preferred master browsers. Use this parameter with care, because if
572 you have two hosts (whether they are Windows 9x/Me or NT/200x/XP or Samba) on the same local subnet both set
573 with <a class="indexterm" name="id2586506"></a>preferred master to <code class="constant">yes</code>, then periodically and continually
574 they will force an election in order to become the LMB.
575 </p><p>
581 If you want Samba to be a <span class="emphasis"><em>DMB</em></span>, then it is recommended that you also set <a class="indexterm" name="id2586559"></a>preferred master to <code class="constant">yes</code>, because Samba will not become a DMB for the whole of
582 your LAN or WAN if it is not also a LMB on its own broadcast isolated subnet.
583 </p><p>
589 It is possible to configure two Samba servers to attempt to become the DMB for a domain. The first server that
590 comes up will be the DMB. All other Samba servers will attempt to become the DMB every 5 minutes. They will
591 find that another Samba server is already the DMB and will fail. This provides automatic redundancy should the
592 current DMB fail. The network bandwidth overhead of browser elections is relatively small, requiring
593 approximately four UDP packets per machine per election. The maximum size of a UDP packet is 576 bytes.
594 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2586621"></a>Making Samba the Domain Master</h3></div></div></div><p>
599 The domain master browser is responsible for collating the browse lists of multiple subnets so browsing can
600 occur between subnets. You can make Samba act as the domain master browser by setting <a class="indexterm" name="id2586659"></a>domain master = yes in <code class="filename">smb.conf</code>. By default it will not be a domain master browser.
601 </p><p>
604 Do not set Samba to be the domain master for a workgroup that has the same name as an NT/200x domain. If
605 Samba is configured to be the domain master for a workgroup that is present on the same network as a Windows
606 NT/200x domain that has the same name, network browsing problems will certainly be experienced.
607 </p><p>
608 When Samba is the domain master and the master browser, it will listen for master announcements (made roughly
609 every 12 minutes) from LMBs on other subnets and then contact them to synchronize browse lists.
610 </p><p>
613 If you want Samba to be the domain master, you should also set the <a class="indexterm" name="id2586721"></a>os level high
614 enough to make sure it wins elections, and set <a class="indexterm" name="id2586729"></a>preferred master to
616 </p><p>
619 All servers (including Samba) and clients should be using a WINS server to resolve NetBIOS names. If your
620 clients are only using broadcasting to resolve NetBIOS names, then two things will occur:
624 LMBs will be unable to find a DMB because they will be looking only on the local subnet.
625 </p></li><li><p>
627 If a client happens to get hold of a domain-wide browse list and a user attempts to access a
628 host in that list, it will be unable to resolve the NetBIOS name of that host.
629 </p></li></ol></div><p>
631 If, however, both Samba and your clients are using a WINS server, then:
633 LMBs will contact the WINS server and, as long as Samba has registered that it is a DMB with the WINS
634 server, the LMB will receive Samba's IP address as its DMB.
635 </p></li><li><p>
636 When a client receives a domain-wide browse list and a user attempts to access a host in that list, it will
637 contact the WINS server to resolve the NetBIOS name of that host. As long as that host has registered its
638 NetBIOS name with the same WINS server, the user will be able to see that host..
639 </p></li></ol></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2586849"></a>Note about Broadcast Addresses</h3></div></div></div><p>
641 If your network uses a zero-based broadcast address (for example, if it ends in a 0), then you will strike problems. Windows for Workgroups
642 does not seem to support a zeros broadcast, and you will probably find that browsing and name lookups will not work.
643 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2586871"></a>Multiple Interfaces</h3></div></div></div><p>
645 Samba supports machines with multiple network interfaces. If you have multiple interfaces, you will
646 need to use the <a class="indexterm" name="id2586888"></a>interfaces option in <code class="filename">smb.conf</code> to configure them. For example, the
647 machine you are working with has 4 network interfaces; <code class="literal">eth0</code>, <code class="literal">eth1</code>,
648 <code class="literal">eth2</code>, <code class="literal">eth3</code> and only interfaces <code class="literal">eth1</code> and
649 <code class="literal">eth4</code> should be used by Samba. In this case, the following <code class="filename">smb.conf</code> file entries would
650 permit that intent:
651 </p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id2586951"></a><em class="parameter"><code>interfaces = eth1, eth4</code></em></td></tr><tr><td><a class="indexterm" name="id2586964"></a><em class="parameter"><code>bind interfaces only = Yes</code></em></td></tr></table><p>
659 The <a class="indexterm" name="id2587024"></a>bind interfaces only = Yes is necessary to exclude TCP/IP session
660 services (ports 135, 139, and 445) over the interfaces that are not specified. Please be aware that
661 <span><strong class="command">nmbd</strong></span> will listen for incoming UDP port 137 packets on the unlisted interfaces, but it will
662 not answer them. It will, however, send its broadcast packets over the unlisted interfaces. Total isolation of
663 ethernet interface requires the use of a firewall to block ports 137 and 138 (UDP), and ports 135, 139, and
664 445 (TCP) on all network interfaces that must not be able to access the Samba server.
665 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2587048"></a>Use of the Remote Announce Parameter</h3></div></div></div><p>
668 that all the NetBIOS names on a network get announced to a remote network.
670 </p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id2587086"></a><em class="parameter"><code>remote announce = 192.168.12.23 [172.16.21.255] ...</code></em></td></tr></table><p>
672 </p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id2587108"></a><em class="parameter"><code>remote announce = 192.168.12.23/MIDEARTH [172.16.21.255/ELVINDORF] ...</code></em></td></tr></table><p>
674 where:
675 </p><div class="variablelist"><dl><dt><span class="term"><em class="replaceable"><code>192.168.12.23</code></em> and <em class="replaceable"><code>172.16.21.255</code></em></span></dt><dd><p>
678 is either the LMB IP address or the broadcast address of the remote network.
679 That is, the LMB is at 192.168.1.23, or the address could be given as 172.16.21.255 where the netmask
681 address of the remote network, every host will receive our announcements. This is noisy and therefore
682 undesirable but may be necessary if we do not know the IP address of the remote LMB.
683 </p></dd><dt><span class="term"><em class="replaceable"><code>WORKGROUP</code></em></span></dt><dd><p>is optional and can be either our own workgroup or that of the remote network. If you use the
684 workgroup name of the remote network, our NetBIOS machine names will end up looking like
685 they belong to that workgroup. This may cause name resolution problems and should be avoided.
686 </p></dd></dl></div><p>
687 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2587183"></a>Use of the Remote Browse Sync Parameter</h3></div></div></div><p>
690 The <a class="indexterm" name="id2587205"></a>remote browse sync parameter of <code class="filename">smb.conf</code> is used to announce to another LMB that
691 it must synchronize its NetBIOS name list with our Samba LMB. This works only if the Samba server that has
692 this option is simultaneously the LMB on its network segment.
693 </p><p>
696 </p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id2587238"></a><em class="parameter"><code>remote browse sync</code></em></td></tr></table><p>
700 remote LMB or the network broadcast address of the remote segment.
701 </p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2587274"></a>WINS: The Windows Internetworking Name Server</h2></div></div></div><p>
705 Use of WINS (either Samba WINS or MS Windows NT Server WINS) is highly
706 recommended. Every NetBIOS machine registers its name together with a
707 name_type value for each of several types of service it has available.
708 It registers its name directly as a unique (the type 0x03) name.
709 It also registers its name if it is running the LanManager-compatible
710 server service (used to make shares and printers available to other users)
711 by registering the server (the type 0x20) name.
712 </p><p>
715 All NetBIOS names are up to 15 characters in length. The name_type variable
716 is added to the end of the name, thus creating a 16 character name. Any
718 character. Thus, all NetBIOS names are 16 characters long (including the
719 name_type information).
720 </p><p>
725 WINS can store these 16-character names as they get registered. A client
726 that wants to log onto the network can ask the WINS server for a list
727 of all names that have registered the NetLogon service name_type. This saves
728 broadcast traffic and greatly expedites logon processing. Since broadcast
729 name resolution cannot be used across network segments, this type of
730 information can only be provided via WINS or via a statically configured
732 absence of WINS.
733 </p><p>
739 WINS also forces browse list synchronization by all LMBs. LMBs must synchronize their browse list with the
740 DMB, and WINS helps the LMB to identify its DMB. By definition this will work only within a single workgroup.
741 Note that the DMB has nothing to do with what is referred to as an MS Windows NT domain. The latter is a
742 reference to a security environment, while the DMB refers to the master controller for browse list information
743 only.
744 </p><p>
749 WINS will work correctly only if every client TCP/IP protocol stack
750 is configured to use the WINS servers. Any client that is not
751 configured to use the WINS server will continue to use only broadcast-based
752 name registration, so WINS may never get to know about it. In any case,
753 machines that have not registered with a WINS server will fail name-to-address
754 lookup attempts by other clients and will therefore cause workstation access
755 errors.
756 </p><p>
757 To configure Samba as a WINS server, just add
758 <a class="indexterm" name="id2587465"></a>wins support = yes to the <code class="filename">smb.conf</code>
759 file [global] section.
760 </p><p>
761 To configure Samba to register with a WINS server, just add <a class="indexterm" name="id2587483"></a>wins server = 10.0.0.18 to your <code class="filename">smb.conf</code> file <em class="parameter"><code>[global]</code></em> section.
762 </p><div class="important" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Important</h3><p>
763 Never use <a class="indexterm" name="id2587507"></a>wins support = yes together with <a class="indexterm" name="id2587515"></a>wins server = 10.0.0.18 particularly not using its own IP address. Specifying both will cause <span class="application">nmbd</span>
764 to refuse to start!
765 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2587530"></a>WINS Server Configuration</h3></div></div></div><p>
767 Either a Samba server or a Windows NT server machine may be set up
768 as a WINS server. To configure a Samba server to be a WINS server, you must
769 add to the <code class="filename">smb.conf</code> file on the selected Server the following line to
771 </p><p>
772 </p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id2587569"></a><em class="parameter"><code>wins support = yes</code></em></td></tr></table><p>
773 </p><p>
775 Versions of Samba prior to 1.9.17 had this parameter default to
776 yes. If you have any older versions of Samba on your network, it is
777 strongly suggested you upgrade to a recent version, or at the very
779 </p><p>
780 Machines configured with <a class="indexterm" name="id2587604"></a>wins support = yes will keep a list of
781 all NetBIOS names registered with them, acting as a DNS for NetBIOS names.
782 </p><p>
784 It is strongly recommended to set up only one WINS server. Do not set the
786 server on a network.
787 </p><p>
793 To configure Windows NT/200x Server as a WINS server, install and configure the WINS service. See the Windows
794 NT/200x documentation for details. Windows NT/200x WINS servers can replicate to each other, allowing more
795 than one to be set up in a complex subnet environment. Because Microsoft refuses to document the replication
796 protocols, Samba cannot currently participate in these replications. It is possible that a Samba-to-Samba WINS
797 replication protocol may be defined in the future, in which case more than one Samba machine could be set up
798 as a WINS server. Currently only one Samba server should have the <a class="indexterm" name="id2587683"></a>wins support = yes parameter set.
799 </p><p>
802 After the WINS server has been configured, you must ensure that all machines participating on the network are
803 configured with the address of this WINS server. If your WINS server is a Samba machine, fill in the Samba
804 machine IP address in the <span class="guilabel">Primary WINS Server</span> field of the <span class="guilabel">Control
805 Panel->Network->Protocols->TCP->WINS Server</span> dialogs in Windows 9x/Me or Windows NT/200x. To tell a
806 Samba server the IP address of the WINS server, add the following line to the <em class="parameter"><code>[global]</code></em> section of all <code class="filename">smb.conf</code> files:
807 </p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id2587745"></a><em class="parameter"><code>wins server = <name or IP address></code></em></td></tr></table><p>
809 machine or its IP address.
810 </p><p>
812 server acting as the WINS server itself. If you set both the
816 </p><p>
821 There are two possible scenarios for setting up cross-subnet browsing.
822 The first details setting up cross-subnet browsing on a network containing
824 part of a Windows NT domain. The second details setting up cross-subnet
825 browsing on networks that contain NT domains.
826 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2587836"></a>WINS Replication</h3></div></div></div><p>
829 Samba-3 does not support native WINS replication. There was an approach to implement it, called
830 <code class="filename">wrepld</code>, but it was never ready for action and the development is now discontinued.
831 </p><p>
832 Meanwhile, there is a project named <code class="filename">samba4WINS</code>, which makes it possible to
836 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2587890"></a>Static WINS Entries</h3></div></div></div><p>
841 Adding static entries to your Samba WINS server is actually fairly easy. All you have to do is add a line to
842 <code class="filename">wins.dat</code>, typically located in <code class="filename">/usr/local/samba/var/locks</code> or <code class="filename">/var/run/samba</code>.
843 </p><p>
846 "NAME#TYPE" TTL ADDRESS+ FLAGS
847 </pre><p>
850 where NAME is the NetBIOS name, TYPE is the NetBIOS type, TTL is the time-to-live as an absolute time in
851 seconds, ADDRESS+ is one or more addresses corresponding to the registration, and FLAGS are the NetBIOS flags
852 for the registration.
853 </p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
854 A change that has been made to the <code class="filename">wins.dat</code> will not take effect until <span class="application">nmbd</span> has been
855 restarted. It should be noted that since the <code class="filename">wins.dat</code> file changes dynamically, <span class="application">nmbd</span>
856 should be stopped before editting this file. Do not forget to restart <span class="application">nmbd</span> when this file has been editted.
857 </p></div><p>
858 A typical dynamic entry looks like this:
861 </pre><p>
862 To make a NetBIOS name static (permanent), simply set the TTL to 0, like this:
865 </pre><p>
866 </p><p>
874 The NetBIOS flags may be interpreted as additive hexadecimal values: 00 - Broadcast node registration, 20 -
875 Peer node registration, 40 - Meta node registration, 60 - Hybrid node registration, 02 - Permanent name, 04 -
876 Active name, 80 - Group name. The 'R' indicates this is a registration record. Thus 66R means: Hybrid node
877 active and permanent NetBIOS name. These values may be found in the <code class="filename">nameserv.h</code> header
878 file from the Samba source code repository. These are the values for the NB flags.
879 </p><p>
881 Though this method works with early Samba-3 versions, there is a possibility that it may change in future
882 versions if WINS replication is added.
883 </p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2588121"></a>Helpful Hints</h2></div></div></div><p>
884 The following hints should be carefully considered because they are stumbling points
885 for many new network administrators.
886 </p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2588132"></a>Windows Networking Protocols</h3></div></div></div><p>
889 A common cause of browsing problems results from the installation of more than one protocol on an MS Windows
890 machine.
891 </p><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Warning</h3><p>
892 Do not use more than one protocol on MS Windows clients.
893 </p></div><p>
896 Every NetBIOS machine takes part in a process of electing the LMB (and DMB)
897 every 15 minutes. A set of election criteria is used to determine the order
898 of precedence for winning this election process. A machine running Samba or
899 Windows NT will be biased, so the most suitable machine will predictably
900 win and thus retain its role.
901 </p><p>
908 The election process is <span class="emphasis"><em>fought out, so to speak</em></span> over every NetBIOS network interface. In
909 the case of a Windows 9x/Me machine that has both TCP/IP and IPX installed and has NetBIOS enabled over both
910 protocols, the election will be decided over both protocols. As often happens, if the Windows 9x/Me machine is
911 the only one with both protocols, then the LMB may be won on the NetBIOS interface over the IPX protocol.
912 Samba will then lose the LMB role because Windows 9x/Me will insist it knows who the LMB is. Samba will then
913 cease to function as an LMB, and browse list operation on all TCP/IP-only machines will therefore fail.
914 </p><p>
918 The Windows NT4, 200x, and XP use common protocols. These are roughly
919 referred to as the Windows NT family, but it should be recognized that 2000 and
920 XP/2003 introduce new protocol extensions that cause them to behave
921 differently from MS Windows NT4. Generally, where a server does not support
922 the newer or extended protocol, these will fall back to the NT4 protocols.
923 </p><p>
924 The safest rule of all to follow is: Use only one protocol!
925 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2588278"></a>Name Resolution Order</h3></div></div></div><p>
928 Resolution of NetBIOS names to IP addresses can take place using a number
929 of methods. The only ones that can provide NetBIOS name_type information
930 are:
931 </p><div class="itemizedlist"><ul type="disc"><li><p>WINS the best tool.</p></li><li><p>LMHOSTS static and hard to maintain.</p></li><li><p>Broadcast uses UDP and cannot resolve names across remote segments.</p></li></ul></div><p>
932 Alternative means of name resolution include:
933 </p><div class="itemizedlist"><ul type="disc"><li><p>Static <code class="filename">/etc/hosts</code> hard to maintain and lacks name_type info.</p></li><li><p>DNS is a good choice but lacks essential NetBIOS name_type information.</p></li></ul></div><p>
936 Many sites want to restrict DNS lookups and avoid broadcast name
937 resolution traffic. The <em class="parameter"><code>name resolve order</code></em> parameter is of great help here.
939 </p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id2588396"></a><em class="parameter"><code>name resolve order = wins lmhosts bcast host</code></em></td></tr></table><p>
941 </p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id2588418"></a><em class="parameter"><code>name resolve order = wins lmhosts (eliminates bcast and host)</code></em></td></tr></table><p>
942 The default is:
943 </p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id2588437"></a><em class="parameter"><code>name resolve order = host lmhost wins bcast</code></em></td></tr></table><p>
945 where “<span class="quote">host</span>” refers to the native methods used by the UNIX system to implement the
946 gethostbyname() function call. This is normally controlled by <code class="filename">/etc/host.conf</code>,
947 <code class="filename">/etc/nsswitch.conf</code> and <code class="filename">/etc/resolv.conf</code>.
948 </p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2588485"></a>Technical Overview of Browsing</h2></div></div></div><p>
950 SMB networking provides a mechanism by which clients can access a list
951 of machines in a network called <a class="indexterm" name="id2588501"></a>browse list. This list
952 contains machines that are ready to offer file and/or print services
953 to other machines within the network. It therefore does not include
954 machines that aren't currently able to do server tasks. The browse
955 list is heavily used by all SMB clients. Configuration of SMB
956 browsing has been problematic for some Samba users, hence this
957 document.
958 </p><p>
963 configured to not use NetBIOS over TCP/IP. When configured this way,
964 it is imperative that name resolution (using DNS/LDAP/ADS) be correctly
965 configured and operative. Browsing will not work if name resolution
966 from SMB machine names to IP addresses does not function correctly.
967 </p><p>
970 Where NetBIOS over TCP/IP is enabled, use of a WINS server is highly
971 recommended to aid the resolution of NetBIOS (SMB) names to IP addresses.
972 WINS allows remote segment clients to obtain NetBIOS name_type information
973 that cannot be provided by any other means of name resolution.
974 </p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2588567"></a>Browsing Support in Samba</h3></div></div></div><p>
981 Samba can act as an LMB for a workgroup, and the ability
982 to support domain logons and scripts is now available.
983 </p><p>
987 Samba can also act as a DMB for a workgroup. This
988 means that it will collate lists from LMBs into a
989 wide-area network server list. In order for browse clients to
990 resolve the names they may find in this list, it is recommended that
991 both Samba and your clients use a WINS server.
992 </p><p>
994 Do not set Samba to be the domain master for a workgroup that has the same
995 name as an NT Domain. On each wide-area network, you must only ever have one
996 DMB per workgroup, regardless of whether it is NT, Samba,
997 or any other type of domain master that is providing this service.
998 </p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
1001 <span><strong class="command">nmbd</strong></span> can be configured as a WINS server, but it is not
1002 necessary to specifically use Samba as your WINS server. MS Windows
1003 NT4, Server or Advanced Server 200x can be configured as
1004 your WINS server. In a mixed NT/200x server and Samba environment on
1005 a WAN, it is recommended that you use the Microsoft
1006 WINS server capabilities. In a Samba-only environment, it is
1007 recommended that you use one and only one Samba server as the WINS server.
1008 </p></div><p>
1010 To get browsing to work, you need to run <span><strong class="command">nmbd</strong></span> as usual, but must
1011 use the <a class="indexterm" name="id2588709"></a>workgroup option in <code class="filename">smb.conf</code>
1012 to control what workgroup Samba becomes a part of.
1013 </p><p>
1015 Samba also has a useful option for a Samba server to offer itself for
1016 browsing on another subnet. It is recommended that this option is
1017 used only for “<span class="quote">unusual</span>” purposes: announcements over the Internet, for
1020 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2588756"></a>Problem Resolution</h3></div></div></div><p>
1024 to track down the problem. Try a <a class="indexterm" name="id2588785"></a>log level of 2 or 3 for finding
1025 problems. Also note that the current browse list usually gets stored
1027 </p><p>
1030 If it does not work, you should still be able to
1031 type the server name as <code class="filename">\\SERVER</code> in <span><strong class="command">filemanager</strong></span>, then
1032 press enter, and <span><strong class="command">filemanager</strong></span> should display the list of available shares.
1033 </p><p>
1036 Some people find browsing fails because they do not have the global
1037 <a class="indexterm" name="id2588855"></a>guest account set to a valid account. Remember that the
1038 IPC$ connection that lists the shares is done as guest and so you must have a valid guest account.
1039 </p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>
1045 The <code class="literal">IPC$</code> share is used by all SMB/CIFS clients to obtain the list of resources
1046 that is available on the server. This is the source of the list of shares and printers when browsing
1047 an SMB/CIFS server (also Windows machines) using the Windows Explorer to browse resources through
1048 the Windows Network Neighborhood (also called My Network Places) through to a Windows server. At
1049 this point, the client has opened a connection to the <code class="literal">\\server\IPC4</code> resource.
1050 Clicking on a share will then open up a connection to the <code class="literal">\\server\share</code>.
1051 </p></div><p>
1056 MS Windows 2000 and later (as with Samba) can be configured to disallow
1057 anonymous (i.e., guest account) access to the IPC$ share. In that case, the
1059 name of the currently logged-in user to query the IPC$ share. MS Windows
1060 9x/Me clients are not able to do this and thus will not be able to browse
1061 server resources.
1062 </p><p>
1064 The other big problem people have is that their broadcast address,
1065 netmask, or IP address is wrong (specified with the <a class="indexterm" name="id2588980"></a>interfaces option
1067 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2588995"></a>Cross-Subnet Browsing</h3></div></div></div><p>
1070 Since the release of Samba 1.9.17 (alpha1), Samba has supported the replication of browse lists across subnet
1071 boundaries. This section describes how to set this feature up in different settings.
1072 </p><p>
1079 To see browse lists that span TCP/IP subnets (i.e., networks separated by routers that do not pass broadcast
1080 traffic), you must set up at least one WINS server. The WINS server acts as a DNS for NetBIOS names. This will
1081 allow NetBIOS name-to-IP address translation to be completed by a direct query of the WINS server. This is
1082 done via a directed UDP packet on port 137 to the WINS server machine. The WINS server avoids the necessity of
1083 default NetBIOS name-to-IP address translation, which is done using UDP broadcasts from the querying machine.
1084 This means that machines on one subnet will not be able to resolve the names of machines on another subnet
1085 without using a WINS server. The Samba hacks, <em class="parameter"><code>remote browse sync</code></em>, and <em class="parameter"><code>remote
1086 announce</code></em> are designed to get around the natural limitations that prevent UDP broadcast
1087 propagation. The hacks are not a universal solution and they should not be used in place of WINS, they are
1088 considered last resort methods.
1089 </p><p>
1094 Remember, for browsing across subnets to work correctly, all machines, be they Windows 95, Windows NT, or
1095 Samba servers, must have the IP address of a WINS server given to them by a DHCP server or by manual
1096 configuration: for Windows 9x/Me and Windows NT/200x/XP, this is in the TCP/IP Properties, under Network
1098 </p><p>
1102 It is possible to operate Samba-3 without NetBIOS over TCP/IP. If you do this, be warned that if used outside
1103 of MS ADS, this will forgo network browsing support. ADS permits network browsing support through DNS,
1104 providing appropriate DNS records are inserted for all Samba servers.
1105 </p><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2589167"></a>Behavior of Cross-Subnet Browsing</h4></div></div></div><p>
1108 Cross-subnet browsing is a complicated dance, containing multiple moving parts. It has taken Microsoft several
1109 years to get the code that correctly achieves this, and Samba lags behind in some areas. Samba is capable of
1110 cross-subnet browsing when configured correctly.
1111 </p><p>
1112 Consider a network set up as in <a href="NetworkBrowsing.html#browsing1" title="Figure 10.1. Cross-Subnet Browsing Example.">Cross-Subnet Browsing Example</a>.
1113 </p><div class="figure"><a name="browsing1"></a><p class="title"><b>Figure 10.1. Cross-Subnet Browsing Example.</b></p><div class="figure-contents"><div class="mediaobject"><img src="images/browsing1.png" width="216" alt="Cross-Subnet Browsing Example."></div></div></div><br class="figure-break"><p>
1117 This consists of three subnets (1, 2, 3) connected by two routers (R1, R2), which do not pass broadcasts.
1118 Subnet 1 has five machines on it, subnet 2 has four machines, and subnet 3 has four machines. Assume for the
1119 moment that all machines are configured to be in the same workgroup (for simplicity's sake). Machine N1_C on
1120 subnet 1 is configured as the DMB (i.e., it will collate the browse lists for the workgroup). Machine N2_D is
1121 configured as a WINS server, and all the other machines are configured to register their NetBIOS names with
1122 it.
1123 </p><p>
1127 As these machines are booted up, elections for master browsers
1128 take place on each of the three subnets. Assume that machine
1130 subnet 3. These machines are known as LMBs for
1131 their particular subnet. N1_C has an advantage in winning as the
1132 LMB on subnet 1 because it is set up as DMB.
1133 </p><p>
1136 On each of the three networks, machines that are configured to
1137 offer sharing services will broadcast that they are offering
1138 these services. The LMB on each subnet will
1139 receive these broadcasts and keep a record of the fact that
1140 the machine is offering a service. This list of records is
1141 the basis of the browse list. For this case, assume that
1142 all the machines are configured to offer services, so all machines
1143 will be on the browse list.
1144 </p><p>
1150 For each network, the LMB on that network is
1151 considered <span class="emphasis"><em>authoritative</em></span> for all the names it receives via
1152 local broadcast. This is because a machine seen by the LMB
1153 via a local broadcast must be on the same network as the
1155 and <span class="emphasis"><em>verifiable</em></span> resource. Machines on other networks that
1156 the LMBs learn about when collating their
1157 browse lists have not been directly seen. These records are
1159 </p><p>
1161 At this point the browse lists appear as shown in <a href="NetworkBrowsing.html#browsubnet" title="Table 10.1. Browse Subnet Example 1">Browse Subnet Example 1</a> (these are
1162 the machines you would see in your network neighborhood if you looked in it on a particular network right now).
1163 </p><p>
1164 </p><div class="table"><a name="browsubnet"></a><p class="title"><b>Table 10.1. Browse Subnet Example 1</b></p><div class="table-contents"><table summary="Browse Subnet Example 1" border="1"><colgroup><col><col><col></colgroup><thead><tr><th align="left">Subnet</th><th align="left">Browse Master</th><th align="left">List</th></tr></thead><tbody><tr><td align="left">Subnet1</td><td align="left">N1_C</td><td align="left">N1_A, N1_B, N1_C, N1_D, N1_E</td></tr><tr><td align="left">Subnet2</td><td align="left">N2_B</td><td align="left">N2_A, N2_B, N2_C, N2_D</td></tr><tr><td align="left">Subnet3</td><td align="left">N3_D</td><td align="left">N3_A, N3_B, N3_C, N3_D</td></tr></tbody></table></div></div><p><br class="table-break">
1165 </p><p>
1166 At this point all the subnets are separate, and no machine is seen across any of the subnets.
1167 </p><p>
1172 Now examine subnet 2 in <a href="NetworkBrowsing.html#brsbex" title="Table 10.2. Browse Subnet Example 2">Browse Subnet Example 2</a>.
1173 As soon as N2_B has become the LMB, it looks for a DMB with which to synchronize
1174 its browse list. It does this by querying the WINS server
1175 (N2_D) for the IP address associated with the NetBIOS name
1177 (N1_C) with the WINS server as soon as it was started.
1178 </p><p>
1183 Once N2_B knows the address of the DMB, it
1184 tells it that is the LMB for subnet 2 by
1185 sending a <span class="emphasis"><em>MasterAnnouncement</em></span> packet as a UDP port 138 packet.
1186 It then synchronizes with it by doing a <span class="emphasis"><em>NetServerEnum2</em></span> call. This
1187 tells the DMB to send it all the server
1188 names it knows about. Once the DMB receives
1189 the <span class="emphasis"><em>MasterAnnouncement</em></span> packet, it schedules a synchronization
1190 request to the sender of that packet. After both synchronizations
1191 are complete, the browse lists look like those in <a href="NetworkBrowsing.html#brsbex" title="Table 10.2. Browse Subnet Example 2">Browse Subnet Example 2</a>
1192 </p><div class="table"><a name="brsbex"></a><p class="title"><b>Table 10.2. Browse Subnet Example 2</b></p><div class="table-contents"><table summary="Browse Subnet Example 2" border="1"><colgroup><col align="left"><col align="left"><col align="justify"></colgroup><thead><tr><th align="left">Subnet</th><th align="left">Browse Master</th><th align="justify">List</th></tr></thead><tbody><tr><td align="left">Subnet1</td><td align="left">N1_C</td><td align="justify">N1_A, N1_B, N1_C, N1_D, N1_E,
1193 N2_A(*), N2_B(*), N2_C(*), N2_D(*)</td></tr><tr><td align="left">Subnet2</td><td align="left">N2_B</td><td align="justify">N2_A, N2_B, N2_C, N2_D, N1_A(*),
1194 N1_B(*), N1_C(*), N1_D(*), N1_E(*)</td></tr><tr><td align="left">Subnet3</td><td align="left">N3_D</td><td align="justify">N3_A, N3_B, N3_C, N3_D</td></tr></tbody></table></div></div><br class="table-break"><p>
1196 Servers with an (*) after them are non-authoritative names.
1197 </p><p>
1199 At this point users looking in their Network Neighborhood on
1201 subnet 3 will still see only the servers on their own subnet.
1202 </p><p>
1204 The same sequence of events that occurred for N2_B now occurs
1205 for the LMB on subnet 3 (N3_D). When it
1206 synchronizes browse lists with the DMB (N1_A)
1207 it gets both the server entries on subnet 1 and those on
1208 subnet 2. After N3_D has synchronized with N1_C and vica versa,
1209 the browse lists will appear as shown in <a href="NetworkBrowsing.html#brsex2" title="Table 10.3. Browse Subnet Example 3">Browse Subnet Example 3</a>
1210 </p><div class="table"><a name="brsex2"></a><p class="title"><b>Table 10.3. Browse Subnet Example 3</b></p><div class="table-contents"><table summary="Browse Subnet Example 3" border="1"><colgroup><col align="left"><col align="left"><col align="justify"></colgroup><thead><tr><th align="left">Subnet</th><th align="left">Browse Master</th><th align="justify">List</th></tr></thead><tbody><tr><td align="left">Subnet1</td><td align="left">N1_C</td><td align="justify">N1_A, N1_B, N1_C, N1_D, N1_E,
1211 N2_A(*), N2_B(*), N2_C(*), N2_D(*), N3_A(*), N3_B(*), N3_C(*), N3_D(*)</td></tr><tr><td align="left">Subnet2</td><td align="left">N2_B</td><td align="justify">N2_A, N2_B, N2_C, N2_D, N1_A(*),
1212 N1_B(*), N1_C(*), N1_D(*), N1_E(*)</td></tr><tr><td align="left">Subnet3</td><td align="left">N3_D</td><td align="justify">N3_A, N3_B, N3_C, N3_D, N1_A(*),
1213 N1_B(*), N1_C(*), N1_D(*), N1_E(*), N2_A(*), N2_B(*), N2_C(*), N2_D(*)</td></tr></tbody></table></div></div><br class="table-break"><p>
1214 Servers with an (*) after them are non-authoritative names.
1215 </p><p>
1216 At this point, users looking in their Network Neighborhood on
1219 </p><p>
1223 Finally, the LMB for subnet 2 (N2_B) will sync again
1224 with the DMB (N1_C) and will receive the missing
1225 server entries. Finally, as when a steady state (if no machines
1226 are removed or shut off) has been achieved, the browse lists will appear
1227 as shown in <a href="NetworkBrowsing.html#brsex3" title="Table 10.4. Browse Subnet Example 4">Browse Subnet Example 4</a>.
1228 </p><div class="table"><a name="brsex3"></a><p class="title"><b>Table 10.4. Browse Subnet Example 4</b></p><div class="table-contents"><table summary="Browse Subnet Example 4" border="1"><colgroup><col align="left"><col align="left"><col align="justify"></colgroup><thead><tr><th align="left">Subnet</th><th align="left">Browse Master</th><th align="justify">List</th></tr></thead><tbody><tr><td align="left">Subnet1</td><td align="left">N1_C</td><td align="justify">N1_A, N1_B, N1_C, N1_D, N1_E,
1229 N2_A(*), N2_B(*), N2_C(*), N2_D(*), N3_A(*), N3_B(*),
1230 N3_C(*), N3_D(*)</td></tr><tr><td align="left">Subnet2</td><td align="left">N2_B</td><td align="justify">N2_A, N2_B, N2_C, N2_D, N1_A(*),
1231 N1_B(*), N1_C(*), N1_D(*), N1_E(*), N3_A(*), N3_B(*),
1232 N3_C(*), N3_D(*)</td></tr><tr><td align="left">Subnet3</td><td align="left">N3_D</td><td align="justify">N3_A, N3_B, N3_C, N3_D, N1_A(*),
1233 N1_B(*), N1_C(*), N1_D(*), N1_E(*), N2_A(*), N2_B(*),
1235 Servers with an (*) after them are non-authoritative names.
1236 </p><p>
1237 Synchronizations between the DMB and LMBs
1238 will continue to occur, but this should remain a
1239 steady-state operation.
1240 </p><p>
1241 If either router R1 or R2 fails, the following will occur:
1244 Names of computers on each side of the inaccessible network fragments
1245 will be maintained for as long as 36 minutes in the Network Neighborhood
1246 lists.
1247 </p></li><li><p>
1248 Attempts to connect to these inaccessible computers will fail, but the
1249 names will not be removed from the Network Neighborhood lists.
1250 </p></li><li><p>
1254 If one of the fragments is cut off from the WINS server, it will only
1255 be able to access servers on its local subnet using subnet-isolated
1256 broadcast NetBIOS name resolution. The effect is similar to that of
1257 losing access to a DNS server.
1258 </p></li></ol></div></div></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2590010"></a>Common Errors</h2></div></div></div><p>
1261 Many questions are asked on the mailing lists regarding browsing. The majority of browsing
1262 problems originate from incorrect configuration of NetBIOS name resolution. Some are of
1263 particular note.
1264 </p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2590036"></a>Flushing the Samba NetBIOS Name Cache</h3></div></div></div><p>
1265 How Can One Flush the Samba NetBIOS Name Cache without Restarting Samba?
1266 </p><p>
1271 Samba's <span><strong class="command">nmbd</strong></span> process controls all browse list handling. Under normal circumstances it is
1272 safe to restart <span><strong class="command">nmbd</strong></span>. This will effectively flush the Samba NetBIOS name cache and cause it
1273 to be rebuilt. This does not make certain that a rogue machine name will not reappear
1274 in the browse list. When <span><strong class="command">nmbd</strong></span> is taken out of service, another machine on the network will
1275 become the browse master. This new list may still have the rogue entry in it. If you really
1276 want to clear a rogue machine from the list, every machine on the network must be
1277 shut down and restarted after all machines are down. Failing a complete restart, the only
1278 other thing you can do is wait until the entry times out and is then flushed from the list.
1279 This may take a long time on some networks (perhaps months).
1280 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2590109"></a>Server Resources Cannot Be Listed</h3></div></div></div><p>“<span class="quote">My Client Reports "‘<span class="quote">This server is not configured to list shared resources."</span>’</span>”</p><p>
1281 Your guest account is probably invalid for some reason. Samba uses the
1282 guest account for browsing in <span><strong class="command">smbd</strong></span>. Check that your guest account is
1283 valid.
1284 </p><p>Also see <a class="indexterm" name="id2590137"></a>guest account in the <code class="filename">smb.conf</code> man page.</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2590153"></a>I Get an "<span class="errorname">Unable to browse the network</span>" Error</h3></div></div></div><p>This error can have multiple causes:
1286 </p><div class="itemizedlist"><ul type="disc"><li><p>There is no LMB. Configure <span class="application">nmbd</span>
1287 or any other machine to serve as LMB.</p></li><li><p>You cannot log onto the machine that is the LMB.
1288 Can you log on to it as a guest user? </p></li><li><p>There is no IP connectivity to the LMB.
1289 Can you reach it by broadcast?</p></li></ul></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2590200"></a>Browsing of Shares and Directories is Very Slow</h3></div></div></div><p>“<span class="quote">
1291 There are only two machines on a test network. One is a Samba server, the other a Windows XP machine.
1292 Authentication and logons work perfectly, but when I try to explore shares on the Samba server, the
1293 Windows XP client becomes unresponsive. Sometimes it does not respond for some minutes. Eventually,
1294 Windows Explorer will respond and displays files and directories without problem.
1298 But, the share is immediately available from a command shell (<span><strong class="command">cmd</strong></span>, followed by
1299 exploration with DOS command. Is this a Samba problem, or is it a Windows problem? How can I solve this?
1301 Here are a few possibilities:
1302 </p><div class="variablelist"><dl><dt><span class="term">Bad Networking Hardware</span></dt><dd><p>
1308 Most common defective hardware problems center around low cost or defective hubs, routers,
1309 network interface controllers (NICs), and bad wiring. If one piece of hardware is defective,
1310 the whole network may suffer. Bad networking hardware can cause data corruption. Most bad
1311 networking hardware problems are accompanied by an increase in apparent network traffic,
1312 but not all.
1315 A number of sites have reported similar slow network browsing problems and found that when
1316 the WebClient service is turned off, the problem disappears. This is certainly something
1317 that should be explored because it is a simple solution if it works.
1321 This type of problem is common when one client is configured to use a WINS server (that is
1322 a TCP/IP configuration setting) and there is no WINS server on the network. Alternatively,
1323 this will happen if there is a WINS server and Samba is not configured to use it. The use of
1324 WINS is highly recommended if the network is using NetBIOS over TCP/IP protocols. If use
1325 of NetBIOS over TCP/IP is disabled on all clients, Samba should not be configured as a WINS
1326 server, nor should it be configured to use one.
1330 If use of NetBIOS over TCP/IP is disabled, Active Directory is in use and the DNS server
1331 has been incorrectly configured. For further information refer to
1332 <a href="NetworkBrowsing.html#adsdnstech" title="DNS and Active Directory">DNS and Active Directory</a>.
1333 </p></dd></dl></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2590401"></a>Invalid Cached Share References Affects Network Browsing</h3></div></div></div><p>
1334 Cached references on your MS Windows client (workstation or server) to shares or servers that no longer exist
1335 can cause MS Windows Explorer to appear unresponsive as it tries to connect to these shares. After a delay
1336 (can take a long time) it times out and browsing will appear to be mostly normal again.
1337 </p><p>
1338 To eliminate the problem the stale cached references should be removed. This does not happen automatically and
1339 requires manual intervention. This is a design feature of MS Windows and not anything that Samba can change.
1340 To remove the stale shortcuts found in <span class="emphasis"><em>My Network Places</em></span> which refer to what are now
1341 invalid shares or servers it is necessary to edit the Windows Registry under
1342 <code class="literal">HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\</code>. Edit the entry
1343 <code class="literal">MountPoints2</code> (on Windows XP and later, or <code class="literal">MountPoints</code> on Windows 2000
1344 and earlier). Remove all keys named <code class="literal">\\server\share</code> (where 'server' and 'share' refer to a
1345 non-existent server or share). Note that this must be done for every user profile that has such stale
1346 references. Alternately, you can delete the shortcuts from the MS Windows Explorer in <code class="literal">My Network
1347 Places</code> just by right-clicking them and selecting <span class="emphasis"><em>Delete.</em></span>
1348 </p><p>
1349 Samba users have reported that these stale references negatively affect network browsing with Windows, Samba,
1350 and Novell servers. It is suspected to be a universal problem not directly related to the Samba
1351 server. Samba users may experience this more often due to Samba being somewhat viewed as an experimenter's
1352 toolkit. This results from the fact that a user might go through several reconfigurations and incarnations of
1353 their Samba server, by different names, with different shares, increasing the chances for having stale
1354 (invalid) cached share references. Windows clients do not seem to expire these references.
1355 </p><p>
1356 It is common for <span class="emphasis"><em>Open</em></span> dialog boxes (for example; in Word and Excel) to respond very
1357 slowly, as they attempt to locate all of the cached references, even if they are not in the current directory
1358 being accessed.
1359 </p></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ChangeNotes.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="passdb.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 9. Important Samba-3.0.23 Change Notes </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 11. Account Information Databases</td></tr></table></div></body></html>