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| author | Jelmer Vernooij <jelmer@samba.org> | 2003-08-13 03:57:48 +0000 |
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| committer | Jelmer Vernooij <jelmer@samba.org> | 2003-08-13 03:57:48 +0000 |
| commit | cb6b82b5dc6ff89a0fe6ed4a1078fca1dfedb567 (patch) | |
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diff --git a/docs/htmldocs/NetworkBrowsing.html b/docs/htmldocs/NetworkBrowsing.html deleted file mode 100644 index 34d48cacc3..0000000000 --- a/docs/htmldocs/NetworkBrowsing.html +++ /dev/null @@ -1,958 +0,0 @@ -<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> -<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Chapter 10. Samba / MS Windows Network Browsing Guide</title><link rel="stylesheet" href="samba.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="SAMBA Project Documentation"><link rel="up" href="optional.html" title="Part III. Advanced Configuration"><link rel="previous" href="optional.html" title="Part III. Advanced Configuration"><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. Samba / MS Windows Network Browsing Guide</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="optional.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. Samba / MS Windows Network Browsing Guide</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><tt class="email"><<a href="mailto:jht@samba.org">jht@samba.org</a>></tt></p></div></div></div></div><div><p class="pubdate">July 5, 1998</p></div><div><p class="pubdate">Updated: April 21, 2003</p></div></div><div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><a href="NetworkBrowsing.html#id2901654">Features and Benefits</a></dt><dt><a href="NetworkBrowsing.html#id2901733">What is Browsing?</a></dt><dt><a href="NetworkBrowsing.html#id2905839">Discussion</a></dt><dd><dl><dt><a href="NetworkBrowsing.html#id2905855">NetBIOS over TCP/IP</a></dt><dt><a href="NetworkBrowsing.html#id2906017">TCP/IP - without NetBIOS</a></dt><dt><a href="NetworkBrowsing.html#id2900986">DNS and Active Directory</a></dt></dl></dd><dt><a href="NetworkBrowsing.html#id2901119">How Browsing Functions</a></dt><dd><dl><dt><a href="NetworkBrowsing.html#id2901245">Setting up WORKGROUP Browsing</a></dt><dt><a href="NetworkBrowsing.html#id2902631">Setting up DOMAIN Browsing</a></dt><dt><a href="NetworkBrowsing.html#browse-force-master">Forcing Samba to be the master</a></dt><dt><a href="NetworkBrowsing.html#id2902896">Making Samba the domain master</a></dt><dt><a href="NetworkBrowsing.html#id2903052">Note about broadcast addresses</a></dt><dt><a href="NetworkBrowsing.html#id2903070">Multiple interfaces</a></dt><dt><a href="NetworkBrowsing.html#id2906571">Use of the Remote Announce parameter</a></dt><dt><a href="NetworkBrowsing.html#id2906680">Use of the Remote Browse Sync parameter</a></dt></dl></dd><dt><a href="NetworkBrowsing.html#id2906741">WINS - The Windows Internetworking Name Server</a></dt><dd><dl><dt><a href="NetworkBrowsing.html#id2906900">Setting up a WINS server</a></dt><dt><a href="NetworkBrowsing.html#id2907094">WINS Replication</a></dt><dt><a href="NetworkBrowsing.html#id2907119">Static WINS Entries</a></dt></dl></dd><dt><a href="NetworkBrowsing.html#id2907203">Helpful Hints</a></dt><dd><dl><dt><a href="NetworkBrowsing.html#id2907217">Windows Networking Protocols</a></dt><dt><a href="NetworkBrowsing.html#id2907283">Name Resolution Order</a></dt></dl></dd><dt><a href="NetworkBrowsing.html#id2907421">Technical Overview of browsing</a></dt><dd><dl><dt><a href="NetworkBrowsing.html#id2907468">Browsing support in Samba</a></dt><dt><a href="NetworkBrowsing.html#id2907575">Problem resolution</a></dt><dt><a href="NetworkBrowsing.html#id2907654">Browsing across subnets</a></dt></dl></dd><dt><a href="NetworkBrowsing.html#id2908270">Common Errors</a></dt><dd><dl><dt><a href="NetworkBrowsing.html#id2908285">How can one flush the Samba NetBIOS name cache without restarting Samba?</a></dt><dt><a href="NetworkBrowsing.html#id2908313">My client reports "This server is not configured to list shared resources"</a></dt></dl></dd></dl></div><p> -This document contains detailed information as well as a fast track guide to -implementing browsing across subnets and / or across workgroups (or domains). -WINS is the best tool for resolution of NetBIOS names to IP addresses. WINS is -NOT involved in browse list handling except by way of name to address resolution. -</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p> -MS Windows 2000 and later can be configured to operate with NO NetBIOS -over TCP/IP. Samba-3 and later also supports this mode of operation. -When the use of NetBIOS over TCP/IP has been disabled then the primary -means for resolution of MS Windows machine names is via DNS and Active Directory. -The following information assumes that your site is running NetBIOS over TCP/IP. -</p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2901654"></a>Features and Benefits</h2></div></div><div></div></div><p> -Someone once referred to the past in terms of: <span class="emphasis"><em>They were the worst of times, -they were the best of times. The more we look back, them more we long for what was and -hope it never returns!</em></span>. -</p><p> -For many MS Windows network administrators, that statement sums up their feelings about -NetBIOS networking precisely. For those who mastered NetBIOS networking, its fickle -nature was just par for the course. For those who never quite managed to tame its -lusty features, NetBIOS is like Paterson's Curse. -</p><p> -For those not familiar with botanical problems in Australia: Paterson's curse, -Echium plantagineum, was introduced to Australia from Europe during the mid-nineteenth -century. Since then it has spread rapidly. The high seed production, with densities of -thousands of seeds per square metre, a seed longevity of more than seven years, and an -ability to germinate at any time of year, given the right conditions, are some of the -features which make it such a persistent weed. -</p><p> -In this chapter we explore vital aspects of SMB (Server Message Block) networking with -a particular focus on SMB as implemented through running NetBIOS (Network Basic -Input / Output System) over TCP/IP. Since Samba does NOT implement SMB or NetBIOS over -any other protocols we need to know how to configure our network environment and simply -remember to use nothing but TCP/IP on all our MS Windows network clients. -</p><p> -Samba provides the ability to implement a WINS (Windows Internetworking Name Server) -and implements extensions to Microsoft's implementation of WINS. These extensions -help Samba to affect stable WINS operations beyond the normal scope of MS WINS. -</p><p> -Please note that WINS is exclusively a service that applies only to those systems -that run NetBIOS over TCP/IP. MS Windows 200x / XP have the capacity to turn off -support for NetBIOS, in which case WINS is of no relevance. Samba-3 supports this also. -</p><p> -For those networks on which NetBIOS has been disabled (ie: WINS is NOT required) -the use of DNS is necessary for host name resolution. -</p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2901733"></a>What is Browsing?</h2></div></div><div></div></div><p> -To most people browsing means that they can see the MS Windows and Samba servers -in the Network Neighborhood, and when the computer icon for a particular server is -clicked, it opens up and shows the shares and printers available on the target server. -</p><p> -What seems so simple is in fact a very complex interaction of different technologies. -The technologies (or methods) employed in making all of this work includes: -</p><table class="simplelist" border="0" summary="Simple list"><tr><td>MS Windows machines register their presence to the network</td></tr><tr><td>Machines announce themselves to other machines on the network</td></tr><tr><td>One or more machine on the network collates the local announcements</td></tr><tr><td>The client machine finds the machine that has the collated list of machines</td></tr><tr><td>The client machine is able to resolve the machine names to IP addresses</td></tr><tr><td>The client machine is able to connect to a target machine</td></tr></table><p> -The Samba application that controls browse list management and name resolution is -called <tt class="filename">nmbd</tt>. The configuration parameters involved in nmbd's operation are: -</p><pre class="programlisting"> - - Browsing options: - ----------------- - * os level - lm announce - lm interval - * preferred master - * local master - * domain master - browse list - enhanced browsing - - Name Resolution Method: - ----------------------- - * name resolve order - - WINS options: - ------------- - dns proxy - wins proxy - * wins server - * wins support - wins hook -</pre><p> -For Samba, the WINS Server and WINS Support are mutually exclusive options. Those marked with -an '*' are the only options that commonly MAY need to be modified. Even if not one of these -parameters is set <tt class="filename">nmbd</tt> will still do it's job. -</p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2905839"></a>Discussion</h2></div></div><div></div></div><p> -Firstly, all MS Windows networking uses SMB (Server Message Block) based messaging. -SMB messaging may be implemented with or without NetBIOS. MS Windows 200x supports -NetBIOS over TCP/IP for backwards compatibility. Microsoft is intent on phasing out NetBIOS -support. -</p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2905855"></a>NetBIOS over TCP/IP</h3></div></div><div></div></div><p> -Samba implements NetBIOS, as does MS Windows NT / 200x / XP, by encapsulating it over TCP/IP. -MS Windows products can do likewise. NetBIOS based networking uses broadcast messaging to -affect browse list management. When running NetBIOS over TCP/IP, this uses UDP based messaging. -UDP messages can be broadcast or unicast. -</p><p> -Normally, only unicast UDP messaging can be forwarded by routers. The -<b class="command">remote announce</b> parameter to smb.conf helps to project browse announcements -to remote network segments via unicast UDP. Similarly, the -<b class="command">remote browse sync</b> parameter of <tt class="filename">smb.conf</tt> -implements browse list collation using unicast UDP. -</p><p> -Secondly, in those networks where Samba is the only SMB server technology, -wherever possible <tt class="filename">nmbd</tt> should be configured on one (1) machine as the WINS -server. This makes it easy to manage the browsing environment. If each network -segment is configured with it's own Samba WINS server, then the only way to -get cross segment browsing to work is by using the -<b class="command">remote announce</b> and the <b class="command">remote browse sync</b> -parameters to your <tt class="filename">smb.conf</tt> file. -</p><p> -If only one WINS server is used for an entire multi-segment network then -the use of the <b class="command">remote announce</b> and the -<b class="command">remote browse sync</b> parameters should NOT be necessary. -</p><p> -As of Samba 3 WINS replication is being worked on. The bulk of the code has -been committed, but it still needs maturation. This is NOT a supported feature -of the Samba-3.0.0 release. Hopefully, this will become a supported feature -of one of the Samba-3 release series. -</p><p> -Right now Samba WINS does not support MS-WINS replication. This means that -when setting up Samba as a WINS server there must only be one <tt class="filename">nmbd</tt> -configured as a WINS server on the network. Some sites have used multiple Samba WINS -servers for redundancy (one server per subnet) and then used -<b class="command">remote browse sync</b> and <b class="command">remote announce</b> -to affect browse list collation across all segments. Note that this means clients -will only resolve local names, and must be configured to use DNS to resolve names -on other subnets in order to resolve the IP addresses of the servers they can see -on other subnets. This setup is not recommended, but is mentioned as a practical -consideration (ie: an 'if all else fails' scenario). -</p><p> -Lastly, take note that browse lists are a collection of unreliable broadcast -messages that are repeated at intervals of not more than 15 minutes. This means -that it will take time to establish a browse list and it can take up to 45 -minutes to stabilise, particularly across network segments. -</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2906017"></a>TCP/IP - without NetBIOS</h3></div></div><div></div></div><p> -All TCP/IP using systems use various forms of host name resolution. The primary -methods for TCP/IP hostname resolutions involves either a static file (<tt class="filename">/etc/hosts -</tt>) or DNS (the Domain Name System). DNS is the technology that makes -the Internet usable. DNS based host name resolution is supported by nearly all TCP/IP -enabled systems. Only a few embedded TCP/IP systems do not support DNS. -</p><p> -When an MS Windows 200x / XP system attempts to resolve a host name to an IP address -it follows a defined path: -</p><div class="orderedlist"><ol type="1"><li><p> - Checks the <tt class="filename">hosts</tt> file. It is located in - <tt class="filename">C:\WinNT\System32\Drivers\etc</tt>. - </p></li><li><p> - Does a DNS lookup - </p></li><li><p> - Checks the NetBIOS name cache - </p></li><li><p> - Queries the WINS server - </p></li><li><p> - Does a broadcast name lookup over UDP - </p></li><li><p> - Looks up entries in LMHOSTS. It is located in - <tt class="filename">C:\WinNT\System32\Drivers\etc</tt>. - </p></li></ol></div><p> -Windows 200x / XP can register it's host name with a Dynamic DNS server. You can -force register with a Dynamic DNS server in Windows 200x / XP using: -<b class="command">ipconfig /registerdns</b> -</p><p> -With Active Directory (ADS), a correctly functioning DNS server is absolutely -essential. In the absence of a working DNS server that has been correctly configured, -MS Windows clients and servers will be totally unable to locate each other, -consequently network services will be severely impaired. -</p><p> -The use of Dynamic DNS is highly recommended with Active Directory, in which case -the use of BIND9 is preferred for it's ability to adequately support the SRV (service) -records that are needed for Active Directory. -</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2900986"></a>DNS and Active Directory</h3></div></div><div></div></div><p> -Occasionally we hear from Unix network administrators who want to use a Unix based Dynamic -DNS server in place of the Microsoft DNS server. While this might be desirable to some, the -MS Windows 200x DNS server is auto-configured to work with Active Directory. It is possible -to use BIND version 8 or 9, but it will almost certainly be necessary to create service records -so that MS Active Directory clients can resolve host names to locate essential network services. -The following are some of the default service records that Active Directory requires: -</p><div class="itemizedlist"><ul type="disc"><li><p>_ldap._tcp.pdc.ms-dcs.<span class="emphasis"><em>Domain</em></span></p><p> - This provides the address of the Windows NT PDC for the Domain. - </p></li><li><p>_ldap._tcp.pdc.ms-dcs.<span class="emphasis"><em>DomainTree</em></span></p><p> - Resolves the addresses of Global Catalog servers in the domain. - </p></li><li><p>_ldap._tcp.<span class="emphasis"><em>site</em></span>.sites.writable.ms-dcs.<span class="emphasis"><em>Domain</em></span></p><p> - Provides list of domain controllers based on sites. - </p></li><li><p>_ldap._tcp.writable.ms-dcs.<span class="emphasis"><em>Domain</em></span></p><p> - Enumerates list of domain controllers that have the writable - copies of the Active Directory data store. - </p></li><li><p>_ldap._tcp.<span class="emphasis"><em>GUID</em></span>.domains.ms-dcs.<span class="emphasis"><em>DomainTree</em></span></p><p> - Entry used by MS Windows clients to locate machines using the - Global Unique Identifier. - </p></li><li><p>_ldap._tcp.<span class="emphasis"><em>Site</em></span>.gc.ms-dcs.<span class="emphasis"><em>DomainTree</em></span></p><p> - Used by MS Windows clients to locate site configuration dependent - Global Catalog server. - </p></li></ul></div></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2901119"></a>How Browsing Functions</h2></div></div><div></div></div><p> -MS Windows machines register their NetBIOS names -(ie: the machine name for each service type in operation) on start -up. The exact method by which this name registration -takes place is determined by whether or not the MS Windows client/server -has been given a WINS server address, whether or not LMHOSTS lookup -is enabled, or if DNS for NetBIOS name resolution is enabled, etc. -</p><p> -In the case where there is no WINS server, all name registrations as -well as name lookups are done by UDP broadcast. This isolates name -resolution to the local subnet, unless LMHOSTS is used to list all -names and IP addresses. In such situations Samba provides a means by -which the Samba server name may be forcibly injected into the browse -list of a remote MS Windows network (using the -<b class="command">remote announce</b> parameter). -</p><p> -Where a WINS server is used, the MS Windows client will use UDP -unicast to register with the WINS server. Such packets can be routed -and thus WINS allows name resolution to function across routed networks. -</p><p> -During the startup process an election will take place to create a -local master browser if one does not already exist. On each NetBIOS network -one machine will be elected to function as the domain master browser. This -domain browsing has nothing to do with MS security domain control. -Instead, the domain master browser serves the role of contacting each local -master browser (found by asking WINS or from LMHOSTS) and exchanging browse -list contents. This way every master browser will eventually obtain a complete -list of all machines that are on the network. Every 11-15 minutes an election -is held to determine which machine will be the master browser. By the nature of -the election criteria used, the machine with the highest uptime, or the -most senior protocol version, or other criteria, will win the election -as domain master browser. -</p><p> -Clients wishing to browse the network make use of this list, but also depend -on the availability of correct name resolution to the respective IP -address/addresses. -</p><p> -Any configuration that breaks name resolution and/or browsing intrinsics -will annoy users because they will have to put up with protracted -inability to use the network services. -</p><p> -Samba supports a feature that allows forced synchronisation -of browse lists across routed networks using the <b class="command">remote -browse sync</b> parameter in the <tt class="filename">smb.conf</tt> file. -This causes Samba to contact the local master browser on a remote network and -to request browse list synchronisation. This effectively bridges -two networks that are separated by routers. The two remote -networks may use either broadcast based name resolution or WINS -based name resolution, but it should be noted that the <b class="command">remote -browse sync</b> parameter provides browse list synchronisation - and -that is distinct from name to address resolution, in other -words, for cross subnet browsing to function correctly it is -essential that a name to address resolution mechanism be provided. -This mechanism could be via DNS, <tt class="filename">/etc/hosts</tt>, -and so on. -</p><div xmlns:ns14="" class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2901245"></a>Setting up WORKGROUP Browsing</h3></div></div><div></div></div><p> -To set up cross subnet browsing on a network containing machines -in up to be in a WORKGROUP, not an NT Domain you need to set up one -Samba server to be the Domain Master Browser (note that this is *NOT* -the same as a Primary Domain Controller, although in an NT Domain the -same machine plays both roles). The role of a Domain master browser is -to collate the browse lists from local master browsers on all the -subnets that have a machine participating in the workgroup. Without -one machine configured as a domain master browser each subnet would -be an isolated workgroup, unable to see any machines on any other -subnet. It is the presence of a domain master browser that makes -cross subnet browsing possible for a workgroup. -</p><p> -In an WORKGROUP environment the domain master browser must be a -Samba server, and there must only be one domain master browser per -workgroup name. To set up a Samba server as a domain master browser, -set the following option in the <i class="parameter"><tt>[global]</tt></i> section -of the <tt class="filename">smb.conf</tt> file : -</p><ns14:p> -</ns14:p><pre class="programlisting"> - domain master = yes -</pre><ns14:p> -</ns14:p><p> -The domain master browser should also preferrably be the local master -browser for its own subnet. In order to achieve this set the following -options in the <i class="parameter"><tt>[global]</tt></i> section of the <tt class="filename">smb.conf</tt> file : -</p><ns14:p> -</ns14:p><pre class="programlisting"> - domain master = yes - local master = yes - preferred master = yes - os level = 65 -</pre><ns14:p> -</ns14:p><p> -The domain master browser may be the same machine as the WINS -server, if you require. -</p><p> -Next, you should ensure that each of the subnets contains a -machine that can act as a local master browser for the -workgroup. Any MS Windows NT/2K/XP/2003 machine should be -able to do this, as will Windows 9x machines (although these -tend to get rebooted more often, so it's not such a good idea -to use these). To make a Samba server a local master browser -set the following options in the <i class="parameter"><tt>[global]</tt></i> section of the -<tt class="filename">smb.conf</tt> file : -</p><ns14:p> -</ns14:p><pre class="programlisting"> - domain master = no - local master = yes - preferred master = yes - os level = 65 -</pre><ns14:p> -</ns14:p><p> -Do not do this for more than one Samba server on each subnet, -or they will war with each other over which is to be the local -master browser. -</p><p> -The <i class="parameter"><tt>local master</tt></i> parameter allows Samba to act as a -local master browser. The <i class="parameter"><tt>preferred master</tt></i> causes nmbd -to force a browser election on startup and the <i class="parameter"><tt>os level</tt></i> -parameter sets Samba high enough so that it should win any browser elections. -</p><p> -If you have an NT machine on the subnet that you wish to -be the local master browser then you can disable Samba from -becoming a local master browser by setting the following -options in the <i class="parameter"><tt>[global]</tt></i> section of the -<tt class="filename">smb.conf</tt> file : -</p><ns14:p> -</ns14:p><pre class="programlisting"> - domain master = no - local master = no - preferred master = no - os level = 0 -</pre><ns14:p> -</ns14:p></div><div xmlns:ns15="" class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2902631"></a>Setting up DOMAIN Browsing</h3></div></div><div></div></div><p> -If you are adding Samba servers to a Windows NT Domain then -you must not set up a Samba server as a domain master browser. -By default, a Windows NT Primary Domain Controller for a domain -is also the Domain master browser for that domain, and many -things will break if a Samba server registers the Domain master -browser NetBIOS name (<i class="replaceable"><tt>DOMAIN</tt></i><1B>) -with WINS instead of the PDC. -</p><p> -For subnets other than the one containing the Windows NT PDC -you may set up Samba servers as local master browsers as -described. To make a Samba server a local master browser set -the following options in the <b class="command">[global]</b> section -of the <tt class="filename">smb.conf</tt> file : -</p><ns15:p> -</ns15:p><pre class="programlisting"> - domain master = no - local master = yes - preferred master = yes - os level = 65 -</pre><ns15:p> -</ns15:p><p> -If you wish to have a Samba server fight the election with machines -on the same subnet you may set the <i class="parameter"><tt>os level</tt></i> parameter -to lower levels. By doing this you can tune the order of machines that -will become local master browsers if they are running. For -more details on this see the section <a href="NetworkBrowsing.html#browse-force-master" title="Forcing Samba to be the master"> -Forcing Samba to be the master browser</a> -below. -</p><p> -If you have Windows NT machines that are members of the domain -on all subnets, and you are sure they will always be running then -you can disable Samba from taking part in browser elections and -ever becoming a local master browser by setting following options -in the <i class="parameter"><tt>[global]</tt></i> section of the <tt class="filename">smb.conf</tt> -file : -</p><ns15:p> -</ns15:p><pre class="programlisting"> - domain master = no - local master = no - preferred master = no - os level = 0 -</pre><ns15:p> -</ns15: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></div></div><p> -Who becomes the <i class="parameter"><tt>master browser</tt></i> is determined by an election -process using broadcasts. Each election packet contains a number of parameters -which determine what precedence (bias) a host should have in the -election. By default Samba uses a very low precedence and thus loses -elections to just about anyone else. -</p><p> -If you want Samba to win elections then just set the <i class="parameter"><tt>os level</tt></i> global -option in <tt class="filename">smb.conf</tt> to a higher number. It defaults to 0. Using 34 -would make it win all elections over every other system (except other -samba systems!) -</p><p> -A <i class="parameter"><tt>os level</tt></i> of 2 would make it beat WfWg and Win95, but not MS Windows -NT/2K Server. A MS Windows NT/2K Server domain controller uses level 32. -</p><p>The maximum os level is 255</p><p> -If you want Samba to force an election on startup, then set the -<i class="parameter"><tt>preferred master</tt></i> global option in <tt class="filename">smb.conf</tt> to <tt class="constant">yes</tt>. Samba will -then have a slight advantage over other potential master browsers -that are not preferred master browsers. Use this parameter with -care, as if you have two hosts (whether they are Windows 95 or NT or -Samba) on the same local subnet both set with <i class="parameter"><tt>preferred master</tt></i> to -<tt class="constant">yes</tt>, then periodically and continually they will force an election -in order to become the local master browser. -</p><p> -If you want Samba to be a <i class="parameter"><tt>domain master browser</tt></i>, then it is -recommended that you also set <i class="parameter"><tt>preferred master</tt></i> to <tt class="constant">yes</tt>, because -Samba will not become a domain master browser for the whole of your -LAN or WAN if it is not also a local master browser on its own -broadcast isolated subnet. -</p><p> -It is possible to configure two Samba servers to attempt to become -the domain master browser for a domain. The first server that comes -up will be the domain master browser. All other Samba servers will -attempt to become the domain master browser every 5 minutes. They -will find that another Samba server is already the domain master -browser and will fail. This provides automatic redundancy, should -the current domain master browser fail. -</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2902896"></a>Making Samba the domain master</h3></div></div><div></div></div><p> -The domain master is responsible for collating the browse lists of -multiple subnets so that browsing can occur between subnets. You can -make Samba act as the domain master by setting <i class="parameter"><tt>domain master = yes</tt></i> -in <tt class="filename">smb.conf</tt>. By default it will not be a domain master. -</p><p> -Note that you should <span class="emphasis"><em>not</em></span> set Samba to be the domain master for a -workgroup that has the same name as an NT Domain. -</p><p> -When Samba is the domain master and the master browser, it will listen -for master announcements (made roughly every twelve minutes) from local -master browsers on other subnets and then contact them to synchronise -browse lists. -</p><p> -If you want Samba to be the domain master then I suggest you also set -the <i class="parameter"><tt>os level</tt></i> high enough to make sure it wins elections, and set -<i class="parameter"><tt>preferred master</tt></i> to <tt class="constant">yes</tt>, to get Samba to force an election on -startup. -</p><p> -Note that all your servers (including Samba) and clients should be -using a WINS server to resolve NetBIOS names. If your clients are only -using broadcasting to resolve NetBIOS names, then two things will occur: -</p><div class="orderedlist"><ol type="1"><li><p> - your local master browsers will be unable to find a domain master - browser, as it will only be looking on the local subnet. - </p></li><li><p> - if a client happens to get hold of a domain-wide browse list, and - a user attempts to access a host in that list, it will be unable to - resolve the NetBIOS name of that host. - </p></li></ol></div><p> -If, however, both Samba and your clients are using a WINS server, then: -</p><div class="orderedlist"><ol type="1"><li><p> - your local master browsers will contact the WINS server and, as long as - Samba has registered that it is a domain master browser with the WINS - server, your local master browser will receive Samba's IP address - as its domain master browser. - </p></li><li><p> - when a client receives a domain-wide browse list, and a user attempts - to access a host in that list, it will contact the WINS server to - resolve the NetBIOS name of that host. as long as that host has - registered its NetBIOS name with the same WINS server, the user will - be able to see that host. - </p></li></ol></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2903052"></a>Note about broadcast addresses</h3></div></div><div></div></div><p> -If your network uses a "0" based broadcast address (for example if it -ends in a 0) then you will strike problems. Windows for Workgroups -does not seem to support a 0's broadcast and you will probably find -that browsing and name lookups won't work. -</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2903070"></a>Multiple interfaces</h3></div></div><div></div></div><p> -Samba now supports machines with multiple network interfaces. If you -have multiple interfaces then you will need to use the <b class="command">interfaces</b> -option in <tt class="filename">smb.conf</tt> to configure them. -</p></div><div xmlns:ns16="" class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2906571"></a>Use of the Remote Announce parameter</h3></div></div><div></div></div><ns16:p> -The <i class="parameter"><tt>remote announce</tt></i> parameter of -<tt class="filename">smb.conf</tt> can be used to forcibly ensure -that all the NetBIOS names on a network get announced to a remote network. -The syntax of the <i class="parameter"><tt>remote announce</tt></i> parameter is: -</ns16:p><pre class="programlisting"> - remote announce = a.b.c.d [e.f.g.h] ... -</pre><ns16:p> -<span class="emphasis"><em>or</em></span> -</ns16:p><pre class="programlisting"> - remote announce = a.b.c.d/WORKGROUP [e.f.g.h/WORKGROUP] ... -</pre><ns16:p> - -where: -</ns16:p><div class="variablelist"><dl><dt><span class="term"><i class="replaceable"><tt>a.b.c.d</tt></i> and -<i class="replaceable"><tt>e.f.g.h</tt></i></span></dt><dd><p>is either the LMB (Local Master Browser) IP address -or the broadcast address of the remote network. -ie: the LMB is at 192.168.1.10, or the address -could be given as 192.168.1.255 where the netmask -is assumed to be 24 bits (255.255.255.0). -When the remote announcement is made to the broadcast -address of the remote network, every host will receive -our announcements. This is noisy and therefore -undesirable but may be necessary if we do NOT know -the IP address of the remote LMB.</p></dd><dt><span class="term"><i class="replaceable"><tt>WORKGROUP</tt></i></span></dt><dd><p>is optional and can be either our own workgroup -or that of the remote network. If you use the -workgroup name of the remote network then our -NetBIOS machine names will end up looking like -they belong to that workgroup, this may cause -name resolution problems and should be avoided. -</p></dd></dl></div><ns16:p> -</ns16:p></div><div xmlns:ns17="" class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2906680"></a>Use of the Remote Browse Sync parameter</h3></div></div><div></div></div><p> -The <i class="parameter"><tt>remote browse sync</tt></i> parameter of -<tt class="filename">smb.conf</tt> is used to announce to -another LMB that it must synchronise its NetBIOS name list with our -Samba LMB. It works ONLY if the Samba server that has this option is -simultaneously the LMB on its network segment. -</p><ns17:p> -The syntax of the <i class="parameter"><tt>remote browse sync</tt></i> parameter is: - -</ns17:p><pre class="programlisting"> -remote browse sync = <i class="replaceable"><tt>a.b.c.d</tt></i> -</pre><ns17:p> - -where <i class="replaceable"><tt>a.b.c.d</tt></i> is either the IP address of the -remote LMB or else is the network broadcast address of the remote segment. -</ns17:p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2906741"></a>WINS - The Windows Internetworking Name Server</h2></div></div><div></div></div><p> -Use of WINS (either Samba WINS <span class="emphasis"><em>or</em></span> MS Windows NT Server WINS) is highly -recommended. Every NetBIOS machine registers its name together with a -name_type value for each of several types of service it has available. -eg: It registers its name directly as a unique (the type 0x03) name. -It also registers its name if it is running the LanManager compatible -server service (used to make shares and printers available to other users) -by registering the server (the type 0x20) name. -</p><p> -All NetBIOS names are up to 15 characters in length. The name_type variable -is added to the end of the name - thus creating a 16 character name. Any -name that is shorter than 15 characters is padded with spaces to the 15th -character. ie: All NetBIOS names are 16 characters long (including the -name_type information). -</p><p> -WINS can store these 16 character names as they get registered. A client -that wants to log onto the network can ask the WINS server for a list -of all names that have registered the NetLogon service name_type. This saves -broadcast traffic and greatly expedites logon processing. Since broadcast -name resolution can not be used across network segments this type of -information can only be provided via WINS <span class="emphasis"><em>or</em></span> via statically configured -<tt class="filename">lmhosts</tt> files that must reside on all clients in the -absence of WINS. -</p><p> -WINS also serves the purpose of forcing browse list synchronisation by all -LMB's. LMB's must synchronise their browse list with the DMB (domain master -browser) and WINS helps the LMB to identify it's DMB. By definition this -will work only within a single workgroup. Note that the domain master browser -has NOTHING to do with what is referred to as an MS Windows NT Domain. The -later is a reference to a security environment while the DMB refers to the -master controller for browse list information only. -</p><p> -Use of WINS will work correctly only if EVERY client TCP/IP protocol stack -has been configured to use the WINS server/s. Any client that has not been -configured to use the WINS server will continue to use only broadcast based -name registration so that WINS may NEVER get to know about it. In any case, -machines that have not registered with a WINS server will fail name to address -lookup attempts by other clients and will therefore cause workstation access -errors. -</p><p> -To configure Samba as a WINS server just add -<i class="parameter"><tt>wins support = yes</tt></i> to the <tt class="filename">smb.conf</tt> -file [globals] section. -</p><p> -To configure Samba to register with a WINS server just add -<i class="parameter"><tt>wins server = a.b.c.d</tt></i> to your <tt class="filename">smb.conf</tt> file <i class="parameter"><tt>[globals]</tt></i> section. -</p><div class="important" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Important</h3><p> -Never use both <i class="parameter"><tt>wins support = yes</tt></i> together -with <i class="parameter"><tt>wins server = a.b.c.d</tt></i> -particularly not using it's own IP address. -Specifying both will cause <span class="application">nmbd</span> to refuse to start! -</p></div><div xmlns:ns18="" class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2906900"></a>Setting up a WINS server</h3></div></div><div></div></div><p> -Either a Samba machine or a Windows NT Server machine may be set up -as a WINS server. To set a Samba machine to be a WINS server you must -add the following option to the <tt class="filename">smb.conf</tt> file on the selected machine : -in the <i class="parameter"><tt>[globals]</tt></i> section add the line -</p><ns18:p> -</ns18:p><pre class="programlisting"> - wins support = yes -</pre><ns18:p> -</ns18:p><p> -Versions of Samba prior to 1.9.17 had this parameter default to -yes. If you have any older versions of Samba on your network it is -strongly suggested you upgrade to a recent version, or at the very -least set the parameter to 'no' on all these machines. -</p><p> -Machines with <i class="parameter"><tt>wins support = yes</tt></i> will keep a list of -all NetBIOS names registered with them, acting as a DNS for NetBIOS names. -</p><p> -You should set up only ONE WINS server. Do NOT set the -<i class="parameter"><tt>wins support = yes</tt></i> option on more than one Samba -server. -</p><p> -To set up a Windows NT Server as a WINS server you need to set up -the WINS service - see your NT documentation for details. Note that -Windows NT WINS Servers can replicate to each other, allowing more -than one to be set up in a complex subnet environment. As Microsoft -refuses to document these replication protocols, Samba cannot currently -participate in these replications. It is possible in the future that -a Samba->Samba WINS replication protocol may be defined, in which -case more than one Samba machine could be set up as a WINS server -but currently only one Samba server should have the -<i class="parameter"><tt>wins support = yes</tt></i> parameter set. -</p><p> -After the WINS server has been configured you must ensure that all -machines participating on the network are configured with the address -of this WINS server. If your WINS server is a Samba machine, fill in -the Samba machine IP address in the <span class="guilabel">Primary WINS Server</span> field of -the <span class="guilabel">Control Panel->Network->Protocols->TCP->WINS Server</span> dialogs -in Windows 95 or Windows NT. To tell a Samba server the IP address -of the WINS server add the following line to the <i class="parameter"><tt>[global]</tt></i> section of -all <tt class="filename">smb.conf</tt> files : -</p><ns18:p> -</ns18:p><pre class="programlisting"> - wins server = <name or IP address> -</pre><ns18:p> -</ns18:p><p> -where <name or IP address> is either the DNS name of the WINS server -machine or its IP address. -</p><p> -Note that this line MUST NOT BE SET in the <tt class="filename">smb.conf</tt> file of the Samba -server acting as the WINS server itself. If you set both the -<i class="parameter"><tt>wins support = yes</tt></i> option and the -<i class="parameter"><tt>wins server = <name></tt></i> option then -nmbd will fail to start. -</p><p> -There are two possible scenarios for setting up cross subnet browsing. -The first details setting up cross subnet browsing on a network containing -Windows 95, Samba and Windows NT machines that are not configured as -part of a Windows NT Domain. The second details setting up cross subnet -browsing on networks that contain NT Domains. -</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2907094"></a>WINS Replication</h3></div></div><div></div></div><p> -Samba-3 permits WINS replication through the use of the <tt class="filename">wrepld</tt> utility. -This tool is not currently capable of being used as it is still in active development. -As soon as this tool becomes moderately functional we will prepare man pages and enhance this -section of the documentation to provide usage and technical details. -</p></div><div xmlns:ns19="" class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2907119"></a>Static WINS Entries</h3></div></div><div></div></div><p> -Adding static entries to your Samba-3 WINS server is actually fairly easy. -All you have to do is add a line to <tt class="filename">wins.dat</tt>, typically -located in <tt class="filename">/usr/local/samba/var/locks</tt>. -</p><ns19:p> -Entries in <tt class="filename">wins.dat</tt> take the form of - -</ns19:p><pre class="programlisting"> -"NAME#TYPE" TTL ADDRESS+ FLAGS -</pre><ns19:p> - -where NAME is the NetBIOS name, TYPE is the NetBIOS type, TTL is the -time-to-live as an absolute time in seconds, ADDRESS+ is one or more -addresses corresponding to the registration and FLAGS are the NetBIOS -flags for the registration. -</ns19:p><ns19:p> -A typical dynamic entry looks like: -</ns19:p><pre class="programlisting"> -"MADMAN#03" 1055298378 192.168.1.2 66R -</pre><ns19:p> - -To make it static, all that has to be done is set the TTL to 0: - -</ns19:p><pre class="programlisting"> -"MADMAN#03" 0 192.168.1.2 66R -</pre><ns19:p> -</ns19:p><p> -Though this method works with early Samba-3 versions, there's a -possibility that it may change in future versions if WINS replication -is added. -</p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2907203"></a>Helpful Hints</h2></div></div><div></div></div><p> -The following hints should be carefully considered as they are stumbling points -for many new network administrators. -</p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2907217"></a>Windows Networking Protocols</h3></div></div><div></div></div><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Warning</h3><p> -Do NOT use more than one (1) protocol on MS Windows machines -</p></div><p> -A very common cause of browsing problems results from installing more than -one protocol on an MS Windows machine. -</p><p> -Every NetBIOS machine takes part in a process of electing the LMB (and DMB) -every 15 minutes. A set of election criteria is used to determine the order -of precedence for winning this election process. A machine running Samba or -Windows NT will be biased so that the most suitable machine will predictably -win and thus retain it's role. -</p><p> -The election process is "fought out" so to speak over every NetBIOS network -interface. In the case of a Windows 9x machine that has both TCP/IP and IPX -installed and has NetBIOS enabled over both protocols the election will be -decided over both protocols. As often happens, if the Windows 9x machine is -the only one with both protocols then the LMB may be won on the NetBIOS -interface over the IPX protocol. Samba will then lose the LMB role as Windows -9x will insist it knows who the LMB is. Samba will then cease to function -as an LMB and thus browse list operation on all TCP/IP only machines will -fail. -</p><p><span class="emphasis"><em> -Windows 95, 98, 98se, Me are referred to generically as Windows 9x. -The Windows NT4, 2000, XP and 2003 use common protocols. These are roughly -referred to as the WinNT family, but it should be recognised that 2000 and -XP/2003 introduce new protocol extensions that cause them to behave -differently from MS Windows NT4. Generally, where a server does NOT support -the newer or extended protocol, these will fall back to the NT4 protocols. -</em></span></p><p> -The safest rule of all to follow it this - USE ONLY ONE PROTOCOL! -</p></div><div xmlns:ns20="" class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2907283"></a>Name Resolution Order</h3></div></div><div></div></div><p> -Resolution of NetBIOS names to IP addresses can take place using a number -of methods. The only ones that can provide NetBIOS name_type information -are: -</p><table class="simplelist" border="0" summary="Simple list"><tr><td>WINS: the best tool!</td></tr><tr><td>LMHOSTS: is static and hard to maintain.</td></tr><tr><td>Broadcast: uses UDP and can not resolve names across remote segments.</td></tr></table><p> -Alternative means of name resolution includes: -</p><table class="simplelist" border="0" summary="Simple list"><tr><td><tt class="filename">/etc/hosts</tt>: is static, hard to maintain, and lacks name_type info</td></tr><tr><td>DNS: is a good choice but lacks essential name_type info.</td></tr></table><ns20:p> -Many sites want to restrict DNS lookups and want to avoid broadcast name -resolution traffic. The <i class="parameter"><tt>name resolve order</tt></i> parameter is -of great help here. The syntax of the <i class="parameter"><tt>name resolve order</tt></i> -parameter is: -</ns20:p><pre class="programlisting"> -name resolve order = wins lmhosts bcast host -</pre><ns20:p> -<span class="emphasis"><em>or</em></span> -</ns20:p><pre class="programlisting"> -name resolve order = wins lmhosts (eliminates bcast and host) -</pre><ns20:p> -The default is: -</ns20:p><pre class="programlisting"> -name resolve order = host lmhost wins bcast -</pre><ns20:p> -where "host" refers the the native methods used by the Unix system -to implement the gethostbyname() function call. This is normally -controlled by <tt class="filename">/etc/host.conf</tt>, <tt class="filename">/etc/nsswitch.conf</tt> and <tt class="filename">/etc/resolv.conf</tt>. -</ns20:p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2907421"></a>Technical Overview of browsing</h2></div></div><div></div></div><p> -SMB networking provides a mechanism by which clients can access a list -of machines in a network, a so-called <i class="parameter"><tt>browse list</tt></i>. This list -contains machines that are ready to offer file and/or print services -to other machines within the network. Thus it does not include -machines which aren't currently able to do server tasks. The browse -list is heavily used by all SMB clients. Configuration of SMB -browsing has been problematic for some Samba users, hence this -document. -</p><p> -MS Windows 2000 and later, as with Samba 3 and later, can be -configured to not use NetBIOS over TCP/IP. When configured this way, -it is imperative that name resolution (using DNS/LDAP/ADS) be correctly -configured and operative. Browsing will NOT work if name resolution -from SMB machine names to IP addresses does not function correctly. -</p><p> -Where NetBIOS over TCP/IP is enabled use of a WINS server is highly -recommended to aid the resolution of NetBIOS (SMB) names to IP addresses. -WINS allows remote segment clients to obtain NetBIOS name_type information -that can NOT be provided by any other means of name resolution. -</p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2907468"></a>Browsing support in Samba</h3></div></div><div></div></div><p> -Samba facilitates browsing. The browsing is supported by <span class="application">nmbd</span> -and is also controlled by options in the <tt class="filename">smb.conf</tt> file. -Samba can act as a local browse master for a workgroup and the ability -to support domain logons and scripts is now available. -</p><p> -Samba can also act as a domain master browser for a workgroup. This -means that it will collate lists from local browse masters into a -wide area network server list. In order for browse clients to -resolve the names they may find in this list, it is recommended that -both Samba and your clients use a WINS server. -</p><p> -Note that you should NOT set Samba to be the domain master for a -workgroup that has the same name as an NT Domain: on each wide area -network, you must only ever have one domain master browser per workgroup, -regardless of whether it is NT, Samba or any other type of domain master -that is providing this service. -</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p> -Nmbd can be configured as a WINS server, but it is not -necessary to specifically use Samba as your WINS server. MS Windows -NT4, Server or Advanced Server 2000 or 2003 can be configured as -your WINS server. In a mixed NT/2000/2003 server and Samba environment on -a Wide Area Network, it is recommended that you use the Microsoft -WINS server capabilities. In a Samba-only environment, it is -recommended that you use one and only one Samba server as your WINS server. -</p></div><p> -To get browsing to work you need to run nmbd as usual, but will need -to use the <i class="parameter"><tt>workgroup</tt></i> option in <tt class="filename">smb.conf</tt> -to control what workgroup Samba becomes a part of. -</p><p> -Samba also has a useful option for a Samba server to offer itself for -browsing on another subnet. It is recommended that this option is only -used for 'unusual' purposes: announcements over the internet, for -example. See <i class="parameter"><tt>remote announce</tt></i> in the -<tt class="filename">smb.conf</tt> man page. -</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2907575"></a>Problem resolution</h3></div></div><div></div></div><p> -If something doesn't work then hopefully the log.nmbd file will help -you track down the problem. Try a debug level of 2 or 3 for finding -problems. Also note that the current browse list usually gets stored -in text form in a file called <tt class="filename">browse.dat</tt>. -</p><p> -Note that if it doesn't work for you, then you should still be able to -type the server name as <tt class="filename">\\SERVER</tt> in filemanager then -hit enter and filemanager should display the list of available shares. -</p><p> -Some people find browsing fails because they don't have the global -<i class="parameter"><tt>guest account</tt></i> set to a valid account. Remember that the -IPC$ connection that lists the shares is done as guest, and thus you must -have a valid guest account. -</p><p><span class="emphasis"><em> -MS Windows 2000 and upwards (as with Samba) can be configured to disallow -anonymous (ie: Guest account) access to the IPC$ share. In that case, the -MS Windows 2000/XP/2003 machine acting as an SMB/CIFS client will use the -name of the currently logged in user to query the IPC$ share. MS Windows -9X clients are not able to do this and thus will NOT be able to browse -server resources. -</em></span></p><p> -The other big problem people have is that their broadcast address, -netmask or IP address is wrong (specified with the "interfaces" option -in <tt class="filename">smb.conf</tt>) -</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2907654"></a>Browsing across subnets</h3></div></div><div></div></div><p> -Since the release of Samba 1.9.17(alpha1), Samba has supported the -replication of browse lists across subnet boundaries. This section -describes how to set this feature up in different settings. -</p><p> -To see browse lists that span TCP/IP subnets (ie. networks separated -by routers that don't pass broadcast traffic), you must set up at least -one WINS server. The WINS server acts as a DNS for NetBIOS names, allowing -NetBIOS name to IP address translation to be done by doing a direct -query of the WINS server. This is done via a directed UDP packet on -port 137 to the WINS server machine. The reason for a WINS server is -that by default, all NetBIOS name to IP address translation is done -by broadcasts from the querying machine. This means that machines -on one subnet will not be able to resolve the names of machines on -another subnet without using a WINS server. -</p><p> -Remember, for browsing across subnets to work correctly, all machines, -be they Windows 95, Windows NT, or Samba servers must have the IP address -of a WINS server given to them by a DHCP server, or by manual configuration -(for Win95 and WinNT, this is in the TCP/IP Properties, under Network -settings) for Samba this is in the <tt class="filename">smb.conf</tt> file. -</p><div xmlns:ns21="" class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2907703"></a>How does cross subnet browsing work ?</h4></div></div><div></div></div><p> -Cross subnet browsing is a complicated dance, containing multiple -moving parts. It has taken Microsoft several years to get the code -that achieves this correct, and Samba lags behind in some areas. -Samba is capable of cross subnet browsing when configured correctly. -</p><p> -Consider a network set up as follows : -</p><ns21:p> - -</ns21:p><pre class="programlisting"> - (DMB) - N1_A N1_B N1_C N1_D N1_E - | | | | | - ------------------------------------------------------- - | subnet 1 | - +---+ +---+ - |R1 | Router 1 Router 2 |R2 | - +---+ +---+ - | | - | subnet 2 subnet 3 | - -------------------------- ------------------------------------ - | | | | | | | | - N2_A N2_B N2_C N2_D N3_A N3_B N3_C N3_D - (WINS) -</pre><ns21:p> -</ns21:p><p> -Consisting of 3 subnets (1, 2, 3) connected by two routers -(R1, R2) - these do not pass broadcasts. Subnet 1 has 5 machines -on it, subnet 2 has 4 machines, subnet 3 has 4 machines. Assume -for the moment that all these machines are configured to be in the -same workgroup (for simplicity's sake). Machine N1_C on subnet 1 -is configured as Domain Master Browser (ie. it will collate the -browse lists for the workgroup). Machine N2_D is configured as -WINS server and all the other machines are configured to register -their NetBIOS names with it. -</p><p> -As all these machines are booted up, elections for master browsers -will take place on each of the three subnets. Assume that machine -N1_C wins on subnet 1, N2_B wins on subnet 2, and N3_D wins on -subnet 3 - these machines are known as local master browsers for -their particular subnet. N1_C has an advantage in winning as the -local master browser on subnet 1 as it is set up as Domain Master -Browser. -</p><p> -On each of the three networks, machines that are configured to -offer sharing services will broadcast that they are offering -these services. The local master browser on each subnet will -receive these broadcasts and keep a record of the fact that -the machine is offering a service. This list of records is -the basis of the browse list. For this case, assume that -all the machines are configured to offer services so all machines -will be on the browse list. -</p><p> -For each network, the local master browser on that network is -considered 'authoritative' for all the names it receives via -local broadcast. This is because a machine seen by the local -master browser via a local broadcast must be on the same -network as the local master browser and thus is a 'trusted' -and 'verifiable' resource. Machines on other networks that -the local master browsers learn about when collating their -browse lists have not been directly seen - these records are -called 'non-authoritative'. -</p><p> -At this point the browse lists look as follows (these are -the machines you would see in your network neighborhood if -you looked in it on a particular network right now). -</p><ns21:p> -</ns21:p><div class="table"><a name="id2907818"></a><p class="title"><b>Table 10.1. Browse subnet example 1</b></p><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><ns21:p> -</ns21:p><p> -Note that at this point all the subnets are separate, no -machine is seen across any of the subnets. -</p><p> -Now examine subnet 2. As soon as N2_B has become the local -master browser it looks for a Domain master browser to synchronize -its browse list with. It does this by querying the WINS server -(N2_D) for the IP address associated with the NetBIOS name -WORKGROUP<1B>. This name was registered by the Domain master -browser (N1_C) with the WINS server as soon as it was booted. -</p><p> -Once N2_B knows the address of the Domain master browser it -tells it that is the local master browser for subnet 2 by -sending a MasterAnnouncement packet as a UDP port 138 packet. -It then synchronizes with it by doing a NetServerEnum2 call. This -tells the Domain Master Browser to send it all the server -names it knows about. Once the domain master browser receives -the MasterAnnouncement packet it schedules a synchronization -request to the sender of that packet. After both synchronizations -are done the browse lists look like : -</p><ns21:p> -</ns21:p><div class="table"><a name="id2907928"></a><p class="title"><b>Table 10.2. Browse subnet example 2</b></p><table summary="Browse subnet example 2" 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, N2_A(*), N2_B(*), N2_C(*), N2_D(*)</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, N1_A(*), N1_B(*), N1_C(*), N1_D(*), N1_E(*)</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><ns21:p> - -Servers with a (*) after them are non-authoritative names. -</ns21:p><p> -At this point users looking in their network neighborhood on -subnets 1 or 2 will see all the servers on both, users on -subnet 3 will still only see the servers on their own subnet. -</p><p> -The same sequence of events that occured for N2_B now occurs -for the local master browser on subnet 3 (N3_D). When it -synchronizes browse lists with the domain master browser (N1_A) -it gets both the server entries on subnet 1, and those on -subnet 2. After N3_D has synchronized with N1_C and vica-versa -the browse lists look like. -</p><ns21:p> -</ns21:p><div class="table"><a name="id2908028"></a><p class="title"><b>Table 10.3. Browse subnet example 3</b></p><table summary="Browse subnet example 3" 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, 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="left">N2_A, N2_B, N2_C, N2_D, N1_A(*), N1_B(*), N1_C(*), N1_D(*), N1_E(*)</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, N1_A(*), N1_B(*), N1_C(*), N1_D(*), N1_E(*), N2_A(*), N2_B(*), N2_C(*), N2_D(*)</td></tr></tbody></table></div><ns21:p> - -Servers with a (*) after them are non-authoritative names. -</ns21:p><p> -At this point users looking in their network neighborhood on -subnets 1 or 3 will see all the servers on all subnets, users on -subnet 2 will still only see the servers on subnets 1 and 2, but not 3. -</p><p> -Finally, the local master browser for subnet 2 (N2_B) will sync again -with the domain master browser (N1_C) and will receive the missing -server entries. Finally - and as a steady state (if no machines -are removed or shut off) the browse lists will look like : -</p><ns21:p> -</ns21:p><div class="table"><a name="id2908128"></a><p class="title"><b>Table 10.4. Browse subnet example 4</b></p><table summary="Browse subnet example 4" 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, 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="left">N2_A, N2_B, N2_C, N2_D, N1_A(*), N1_B(*), N1_C(*), N1_D(*), N1_E(*), N3_A(*), N3_B(*), N3_C(*), N3_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, N1_A(*), N1_B(*), N1_C(*), N1_D(*), N1_E(*), N2_A(*), N2_B(*), N2_C(*), N2_D(*)</td></tr></tbody></table></div><ns21:p> - -Servers with a (*) after them are non-authoritative names. -</ns21:p><p> -Synchronizations between the domain master browser and local -master browsers will continue to occur, but this should be a -steady state situation. -</p><p> -If either router R1 or R2 fails the following will occur: -</p><div class="orderedlist"><ol type="1"><li><p> - Names of computers on each side of the inaccessible network fragments - will be maintained for as long as 36 minutes, in the network neighbourhood - lists. - </p></li><li><p> - Attempts to connect to these inaccessible computers will fail, but the - names will not be removed from the network neighbourhood lists. - </p></li><li><p> - If one of the fragments is cut off from the WINS server, it will only - be able to access servers on its local subnet, by using subnet-isolated - broadcast NetBIOS name resolution. The effects are similar to that of - losing access to a DNS server. - </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="id2908270"></a>Common Errors</h2></div></div><div></div></div><p> -Many questions are asked on the mailing lists regarding browsing. The majority of browsing -problems originate out of incorrect configuration of NetBIOS name resolution. Some are of -particular note. -</p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2908285"></a>How can one flush the Samba NetBIOS name cache without restarting Samba?</h3></div></div><div></div></div><p> -Samba's nmbd process controls all browse list handling. Under normal circumstances it is -safe to restart nmbd. This will effectively flush the Samba NetBIOS name cache and cause it -to be rebuilt. Note that this does NOT make certain that a rogue machine name will not re-appear -in the browse list. When nmbd is taken out of service another machine on the network will -become the browse master. This new list may still have the rogue entry in it. If you really -want to clear a rogue machine from the list then every machine on the network will need to be -shut down and restarted at after all machines are down. Failing a complete restart, the only -other thing you can do is wait until the entry times out and is then flushed from the list. -This may take a long time on some networks (months). -</p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2908313"></a>My client reports "This server is not configured to list shared resources"</h3></div></div><div></div></div><p> -Your guest account is probably invalid for some reason. Samba uses the -guest account for browsing in smbd. Check that your guest account is -valid. -</p><p>See also <i class="parameter"><tt>guest account</tt></i> in the <tt class="filename">smb.conf</tt> man page.</p></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="optional.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">Part III. Advanced Configuration </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> |