Chapter 10. Samba / MS Windows Network Browsing Guide

Date: Tue, 9 Sep 2003 02:58:53 +0000 Subject: syncing files from 3.0 into HEAD again (This used to be commit bca0bba209255d0effbae6a3d3b6d298f0952c3a) --- docs/htmldocs/NetworkBrowsing.html | 348 ++++++++++++++++--------------------- 1 file changed, 149 insertions(+), 199 deletions(-) (limited to 'docs/htmldocs/NetworkBrowsing.html') diff --git a/docs/htmldocs/NetworkBrowsing.html b/docs/htmldocs/NetworkBrowsing.html index eb4d9858ca..4507c0067f 100644 --- a/docs/htmldocs/NetworkBrowsing.html +++ b/docs/htmldocs/NetworkBrowsing.html @@ -1,4 +1,4 @@ -Chapter 10. Samba / MS Windows Network Browsing Guide

Chapter 10. Samba / MS Windows Network Browsing Guide
Prev	Part III. Advanced Configuration	Next

Chapter 10. Samba / MS Windows Network Browsing Guide

John H. Terpstra

Samba Team

<jht@samba.org>

July 5, 1998

Updated: April 21, 2003

+Chapter 10. Samba / MS Windows Network Browsing Guide

Chapter 10. Samba / MS Windows Network Browsing Guide
Prev	Part III. Advanced Configuration	Next

Chapter 10. Samba / MS Windows Network Browsing Guide

John H. Terpstra

Samba Team

<jht@samba.org>

Jelmer R. Vernooij

The Samba Team

<jelmer@samba.org>

July 5, 1998

Updated: April 21, 2003

Table of Contents

Features and Benefits

What is Browsing?

Discussion

NetBIOS over TCP/IP
TCP/IP - without NetBIOS
DNS and Active Directory

How Browsing Functions

Setting up WORKGROUP Browsing
Setting up DOMAIN Browsing
Forcing Samba to be the master
Making Samba the domain master
Note about broadcast addresses
Multiple interfaces
Use of the Remote Announce parameter
Use of the Remote Browse Sync parameter

WINS - The Windows Internetworking Name Server

Setting up a WINS server
WINS Replication
Static WINS Entries

Helpful Hints

Windows Networking Protocols
Name Resolution Order

Technical Overview of browsing

Browsing support in Samba
Problem resolution
Browsing across subnets

Common Errors

How can one flush the Samba NetBIOS name cache without restarting Samba?
My client reports "This server is not configured to list shared resources"
I get an Unable to browse the network error

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 @@ -9,11 +9,11 @@ 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. -

Features and Benefits

Someone once referred to the past in terms of: 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!. -

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 @@ -38,63 +38,55 @@ help Samba to affect stable WINS operations beyond the normal scope of MS WINS.

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. +support for NetBIOS, in which case WINS is of no relevance. Samba supports this also.

For those networks on which NetBIOS has been disabled (ie: WINS is NOT required) the use of DNS is necessary for host name resolution. -

What is Browsing?

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.

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: -

MS Windows machines register their presence to the network

Machines announce themselves to other machines on the network

One or more machine on the network collates the local announcements

The client machine finds the machine that has the collated list of machines

The client machine is able to resolve the machine names to IP addresses

The client machine is able to connect to a target machine

MS Windows machines register their presence to the network
Machines announce themselves to other machines on the network
One or more machine on the network collates the local announcements
The client machine finds the machine that has the collated list of machines
The client machine is able to resolve the machine names to IP addresses
The client machine is able to connect to a target machine

The Samba application that controls browse list management and name resolution is called nmbd. The configuration parameters involved in nmbd's operation are: -

-		
-	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
-

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. +

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 nmbd will still do it's job. -

Discussion

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. -

NetBIOS over TCP/IP

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. -

Normally, only unicast UDP messaging can be forwarded by routers. The -remote announce parameter to smb.conf helps to project browse announcements +remote announce parameter to smb.conf helps to project browse announcements to remote network segments via unicast UDP. Similarly, the -remote browse sync parameter of smb.conf +remote browse sync parameter of smb.conf implements browse list collation using unicast UDP.

Secondly, in those networks where Samba is the only SMB server technology, @@ -102,12 +94,13 @@ wherever possible nmbd should be configured on one (1) 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 -remote announce and the remote browse sync +remote announce and the remote browse sync parameters to your smb.conf file.

+ If only one WINS server is used for an entire multi-segment network then -the use of the remote announce and the -remote browse sync parameters should NOT be necessary. +the use of the remote announce and the +remote browse sync parameters should NOT be necessary.

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 @@ -118,7 +111,7 @@ 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 nmbd 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 -remote browse sync and remote announce +remote browse sync and remote announce 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 @@ -129,7 +122,10 @@ 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. -

TCP/IP - without NetBIOS

+ + + 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 (/etc/hosts) or DNS (the Domain Name System). DNS is the technology that makes @@ -152,7 +148,7 @@ it follows a defined path:

Looks up entries in LMHOSTS. It is located in C:\WinNT\System32\Drivers\etc. -

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: ipconfig /registerdns @@ -165,8 +161,8 @@ consequently network services will be severely impaired. 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. -

DNS and Active Directory

-Occasionally we hear from Unix network administrators who want to use a Unix based Dynamic +

DNS and Active Directory

+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 @@ -187,7 +183,7 @@ The following are some of the default service records that Active Directory requ

_ldap._tcp.Site.gc.ms-dcs.DomainTree

Used by MS Windows clients to locate site configuration dependent Global Catalog server. -

How Browsing Functions

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 @@ -201,7 +197,7 @@ 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 -remote announce parameter). +remote announce parameter).

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 @@ -229,20 +225,18 @@ will annoy users because they will have to put up with protracted inability to use the network services.

Samba supports a feature that allows forced synchronisation -of browse lists across routed networks using the remote -browse sync parameter in the smb.conf file. +of browse lists across routed networks using the remote browse sync parameter in the smb.conf 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 remote -browse sync parameter provides browse list synchronisation - and +based name resolution, but it should be noted that the remote browse sync 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, /etc/hosts, and so on. -

Setting up WORKGROUP Browsing

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* @@ -261,20 +255,13 @@ workgroup name. To set up a Samba server as a domain master browser, set the following option in the [global] section of the smb.conf file :

-	domain master = yes
-

domain master = yes

-The domain master browser should also preferrably be the local master +The domain master browser should also preferably be the local master browser for its own subnet. In order to achieve this set the following options in the [global] section of the smb.conf file :

-	domain master = yes
-	local master = yes
-	preferred master = yes
-	os level = 65
-

Example 10.1. Domain master browser smb.conf

[global]

domain master = yes

local master = yes

preferred master = yes

os level = 65

The domain master browser may be the same machine as the WINS server, if you require. @@ -288,20 +275,15 @@ to use these). To make a Samba server a local master browser set the following options in the [global] section of the smb.conf file :

-	domain master = no
-	local master = yes
-	preferred master = yes
-	os level = 65
-

Example 10.2. Local master browser smb.conf

[global]

domain master = no

local master = yes

preferred master = yes

os level = 65

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.

-The local master parameter allows Samba to act as a -local master browser. The preferred master causes nmbd -to force a browser election on startup and the os level +The local master parameter allows Samba to act as a +local master browser. The preferred master causes nmbd +to force a browser election on startup and the os level parameter sets Samba high enough so that it should win any browser elections.

If you have an NT machine on the subnet that you wish to @@ -310,13 +292,8 @@ becoming a local master browser by setting the following options in the [global] section of the smb.conf file :

-	domain master = no
-	local master = no
-	preferred master = no
-	os level = 0
-

Setting up DOMAIN Browsing

Example 10.3. smb.conf for not being a master browser

[global]

domain master = no

local master = no

preferred master = no

os level = 0

Setting up DOMAIN Browsing

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 @@ -328,18 +305,13 @@ with WINS instead of the PDC. 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 [global] section +the following options in the [global] section of the smb.conf file :

-	domain master = no
-	local master = yes
-	preferred master = yes
-	os level = 65
-

Example 10.4. Local master browser smb.conf

[global]

domain master = no

local master = yes

preferred master = yes

os level = 65

If you wish to have a Samba server fight the election with machines -on the same subnet you may set the os level parameter +on the same subnet you may set the os level 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 @@ -353,38 +325,33 @@ ever becoming a local master browser by setting following options in the [global] section of the smb.conf file :

-        domain master = no
-        local master = no
-        preferred master = no
-        os level = 0
-

Example 10.5. smb.conf for not being a master browser

[global]

domain master = no

local master = no

preferred master = no

os level = 0

Forcing Samba to be the master

-Who becomes the master browser is determined by an election +Who becomes the master browser 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.

-If you want Samba to win elections then just set the os level global +If you want Samba to win elections then just set the os level global option in smb.conf to a higher number. It defaults to 0. Using 34 would make it win all elections over every other system (except other samba systems!)

-A os level of 2 would make it beat WfWg and Win95, but not MS Windows +A os level 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.

The maximum os level is 255

If you want Samba to force an election on startup, then set the -preferred master global option in smb.conf to yes. Samba will +preferred master global option in smb.conf to yes. 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 preferred master to +Samba) on the same local subnet both set with preferred master to yes, then periodically and continually they will force an election in order to become the local master browser.

-If you want Samba to be a domain master browser, then it is -recommended that you also set preferred master to yes, because + If you want Samba to be a domain master browser, then it is +recommended that you also set preferred master to yes, 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. @@ -396,10 +363,10 @@ 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. -

Making Samba the domain master

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 domain master = yes +make Samba act as the domain master by setting domain master = yes in smb.conf. By default it will not be a domain master.

Note that you should not set Samba to be the domain master for a @@ -411,8 +378,8 @@ master browsers on other subnets and then contact them to synchronise browse lists.

If you want Samba to be the domain master then I suggest you also set -the os level high enough to make sure it wins elections, and set -preferred master to yes, to get Samba to force an election on +the os level high enough to make sure it wins elections, and set +preferred master to yes, to get Samba to force an election on startup.

Note that all your servers (including Samba) and clients should be @@ -438,31 +405,31 @@ If, however, both Samba and your clients are using a WINS server, then: 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. -

Note about broadcast addresses

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. -

Multiple interfaces

Samba now supports machines with multiple network interfaces. If you -have multiple interfaces then you will need to use the interfaces +have multiple interfaces then you will need to use the interfaces option in smb.conf to configure them. -

Use of the Remote Announce parameter

-The remote announce parameter of +

Use of the Remote Announce parameter

+The remote announce parameter of smb.conf can be used to forcibly ensure that all the NetBIOS names on a network get announced to a remote network. -The syntax of the remote announce parameter is: -

-	remote announce = a.b.c.d [e.f.g.h] ...
-

+The syntax of the remote announce parameter is: +

remote announce = a.b.c.d [e.f.g.h] ...

or -

-	remote announce = a.b.c.d/WORKGROUP [e.f.g.h/WORKGROUP] ...
-

remote announce = a.b.c.d/WORKGROUP [e.f.g.h/WORKGROUP] ...

where:

a.b.c.d and -e.f.g.h: is either the LMB (Local Master Browser) IP address +e.f.g.h; + + + + 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 @@ -478,22 +445,20 @@ NetBIOS machine names will end up looking like they belong to that workgroup, this may cause name resolution problems and should be avoided.

Use of the Remote Browse Sync parameter

-The remote browse sync parameter of +

Use of the Remote Browse Sync parameter

+The remote browse sync parameter of smb.conf 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.

-The syntax of the remote browse sync parameter is: +The syntax of the remote browse sync parameter is: -

-remote browse sync = a.b.c.d
-

remote browse sync = a.b.c.d

where a.b.c.d is either the IP address of the remote LMB or else is the network broadcast address of the remote segment. -

WINS - The Windows Internetworking Name Server

Use of WINS (either Samba WINS or 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. @@ -534,36 +499,34 @@ lookup attempts by other clients and will therefore cause workstation access errors.

To configure Samba as a WINS server just add -wins support = yes to the smb.conf -file [globals] section. +wins support = yes to the smb.conf +file [global] section.

To configure Samba to register with a WINS server just add -wins server = a.b.c.d to your smb.conf file [globals] section. +wins server = a.b.c.d to your smb.conf file [global] section.

Important

-Never use both wins support = yes together -with wins server = a.b.c.d +Never use both wins support = yes together +with wins server = a.b.c.d particularly not using it's own IP address. Specifying both will cause nmbd to refuse to start! -

Setting up a WINS server

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 smb.conf file on the selected machine : -in the [globals] section add the line +in the [global] section add the line

-	wins support = yes
-

wins support = yes

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.

-Machines with wins support = yes will keep a list of +Machines with wins support = yes will keep a list of all NetBIOS names registered with them, acting as a DNS for NetBIOS names.

You should set up only ONE WINS server. Do NOT set the -wins support = yes option on more than one Samba +wins support = yes option on more than one Samba server.

To set up a Windows NT Server as a WINS server you need to set up @@ -575,7 +538,7 @@ 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 -wins support = yes parameter set. +wins support = yes parameter set.

After the WINS server has been configured you must ensure that all machines participating on the network are configured with the address @@ -586,17 +549,15 @@ in Windows 95 or Windows NT. To tell a Samba server the IP address of the WINS server add the following line to the [global] section of all smb.conf files :

-	wins server = <name or IP address>
-

wins server = <name or IP address>

where <name or IP address> is either the DNS name of the WINS server machine or its IP address.

Note that this line MUST NOT BE SET in the smb.conf file of the Samba server acting as the WINS server itself. If you set both the -wins support = yes option and the -wins server = <name> option then +wins support = yes option and the +wins server = <name> option then nmbd will fail to start.

There are two possible scenarios for setting up cross subnet browsing. @@ -604,13 +565,13 @@ 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. -

WINS Replication

Samba-3 permits WINS replication through the use of the wrepld 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. -

Static WINS Entries

-Adding static entries to your Samba-3 WINS server is actually fairly easy. +

Static WINS Entries

+Adding static entries to your Samba WINS server is actually fairly easy. All you have to do is add a line to wins.dat, typically located in /usr/local/samba/var/locks.

@@ -639,10 +600,10 @@ To make it static, all that has to be done is set the TTL to 0: 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. -

Helpful Hints

The following hints should be carefully considered as they are stumbling points for many new network administrators. -

Windows Networking Protocols

Warning

Windows Networking Protocols

Warning

Do NOT use more than one (1) protocol on MS Windows machines

A very common cause of browsing problems results from installing more than @@ -672,34 +633,27 @@ 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.

The safest rule of all to follow it this - USE ONLY ONE PROTOCOL! -

Name Resolution Order

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: -

WINS: the best tool!

LMHOSTS: is static and hard to maintain.

Broadcast: uses UDP and can not resolve names across remote segments.

WINS: the best tool!
LMHOSTS: is static and hard to maintain.
Broadcast: uses UDP and can not resolve names across remote segments.

Alternative means of name resolution includes: -

/etc/hosts: is static, hard to maintain, and lacks name_type info

DNS: is a good choice but lacks essential name_type info.

/etc/hosts: is static, hard to maintain, and lacks name_type info
DNS: is a good choice but lacks essential name_type info.

Many sites want to restrict DNS lookups and want to avoid broadcast name -resolution traffic. The name resolve order parameter is -of great help here. The syntax of the name resolve order -parameter is: -

-name resolve order = wins lmhosts bcast host
-

+resolution traffic. The name resolve order parameter is of great help here. +The syntax of the name resolve order parameter is: +

name resolve order = wins lmhosts bcast host

or -

-name resolve order = wins lmhosts  	(eliminates bcast and host)
-

name resolve order = wins lmhosts (eliminates bcast and host)

The default is: -

-name resolve order = host lmhost wins bcast
-

-where "host" refers the the native methods used by the Unix system +

name resolve order = host lmhost wins bcast

+where "host" refers to the native methods used by the UNIX system to implement the gethostbyname() function call. This is normally controlled by /etc/host.conf, /etc/nsswitch.conf and /etc/resolv.conf. -

Technical Overview of browsing

SMB networking provides a mechanism by which clients can access a list -of machines in a network, a so-called browse list. This list +of machines in a network, a so-called browse list. 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 @@ -717,7 +671,7 @@ 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. -

Browsing support in Samba

Samba facilitates browsing. The browsing is supported by nmbd and is also controlled by options in the smb.conf file. Samba can act as a local browse master for a workgroup and the ability @@ -744,15 +698,15 @@ WINS server capabilities. In a Samba-only environment, it is recommended that you use one and only one Samba server as your WINS server.

To get browsing to work you need to run nmbd as usual, but will need -to use the workgroup option in smb.conf +to use the workgroup option in smb.conf to control what workgroup Samba becomes a part of.

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 remote announce in the +example. See remote announce in the smb.conf man page. -

Problem resolution

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 @@ -763,7 +717,7 @@ type the server name as \\SERVER in filemanager then hit enter and filemanager should display the list of available shares.

Some people find browsing fails because they don't have the global -guest account set to a valid account. Remember that the +guest account 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.

@@ -777,7 +731,7 @@ server resources. The other big problem people have is that their broadcast address, netmask or IP address is wrong (specified with the "interfaces" option in smb.conf) -

Browsing across subnets

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. @@ -798,32 +752,14 @@ 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 smb.conf file. -

How does cross subnet browsing work ?

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.

-Consider a network set up as follows : -

- -

-                                   (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)
-

+ Consider a network set up as in the diagram below. +

Figure 10.1. Cross subnet browsing example

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 @@ -865,7 +801,7 @@ 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).

Table 10.1. Browse subnet example 1
Subnet Browse Master List
Subnet1 N1_C N1_A, N1_B, N1_C, N1_D, N1_E
Subnet2 N2_B N2_A, N2_B, N2_C, N2_D
Subnet3 N3_D N3_A, N3_B, N3_C, N3_D

Subnet	Browse Master	List
Subnet1	N1_C	N1_A, N1_B, N1_C, N1_D, N1_E
Subnet2	N2_B	N2_A, N2_B, N2_C, N2_D
Subnet3	N3_D	N3_A, N3_B, N3_C, N3_D

Subnet	Browse Master	List
Subnet1	N1_C	N1_A, N1_B, N1_C, N1_D, N1_E
Subnet2	N2_B	N2_A, N2_B, N2_C, N2_D
Subnet3	N3_D	N3_A, N3_B, N3_C, N3_D

Note that at this point all the subnets are separate, no machine is seen across any of the subnets. @@ -887,7 +823,9 @@ the MasterAnnouncement packet it schedules a synchronization request to the sender of that packet. After both synchronizations are done the browse lists look like :

Table 10.2. Browse subnet example 2
Subnet Browse Master List
Subnet1 N1_C N1_A, N1_B, N1_C, N1_D, N1_E, N2_A(*), N2_B(*), N2_C(*), N2_D(*)
Subnet2 N2_B N2_A, N2_B, N2_C, N2_D, N1_A(*), N1_B(*), N1_C(*), N1_D(*), N1_E(*)
Subnet3 N3_D N3_A, N3_B, N3_C, N3_D

Subnet	Browse Master	List
Subnet1	N1_C	N1_A, N1_B, N1_C, N1_D, N1_E, N2_A(), N2_B(), N2_C(), N2_D()
Subnet2	N2_B	N2_A, N2_B, N2_C, N2_D, N1_A(), N1_B(), N1_C(), N1_D(), N1_E(*)
Subnet3	N3_D	N3_A, N3_B, N3_C, N3_D

Table 10.2. Browse subnet example 2
Subnet Browse Master List
Subnet1 N1_C N1_A, N1_B, N1_C, N1_D, N1_E, +N2_A(*), N2_B(*), N2_C(*), N2_D(*)
Subnet2 N2_B N2_A, N2_B, N2_C, N2_D, N1_A(*), +N1_B(*), N1_C(*), N1_D(*), N1_E(*)
Subnet3 N3_D N3_A, N3_B, N3_C, N3_D

Subnet	Browse Master	List
Subnet1	N1_C	N1_A, N1_B, N1_C, N1_D, N1_E, +N2_A(), N2_B(), N2_C(), N2_D()
Subnet2	N2_B	N2_A, N2_B, N2_C, N2_D, N1_A(), +N1_B(), N1_C(), N1_D(), N1_E(*)
Subnet3	N3_D	N3_A, N3_B, N3_C, N3_D

Servers with a (*) after them are non-authoritative names.

@@ -895,14 +833,17 @@ 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.

-The same sequence of events that occured for N2_B now occurs +The same sequence of events that occurred 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.

Table 10.3. Browse subnet example 3
Subnet Browse Master List
Subnet1 N1_C 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(*)
Subnet2 N2_B N2_A, N2_B, N2_C, N2_D, N1_A(*), N1_B(*), N1_C(*), N1_D(*), N1_E(*)
Subnet3 N3_D 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(*)

Subnet	Browse Master	List
Subnet1	N1_C	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()
Subnet2	N2_B	N2_A, N2_B, N2_C, N2_D, N1_A(), N1_B(), N1_C(), N1_D(), N1_E(*)
Subnet3	N3_D	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(*)

Table 10.3. Browse subnet example 3
Subnet Browse Master List
Subnet1 N1_C 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(*)
Subnet2 N2_B N2_A, N2_B, N2_C, N2_D, N1_A(*), +N1_B(*), N1_C(*), N1_D(*), N1_E(*)
Subnet3 N3_D 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(*)

Subnet	Browse Master	List
Subnet1	N1_C	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()
Subnet2	N2_B	N2_A, N2_B, N2_C, N2_D, N1_A(), +N1_B(), N1_C(), N1_D(), N1_E(*)
Subnet3	N3_D	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(*)

Servers with a (*) after them are non-authoritative names.

@@ -915,7 +856,13 @@ 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 :

Table 10.4. Browse subnet example 4
Subnet Browse Master List
Subnet1 N1_C 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(*)
Subnet2 N2_B 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(*)
Subnet3 N3_D 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(*)

Subnet	Browse Master	List
Subnet1	N1_C	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()
Subnet2	N2_B	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(*)
Subnet3	N3_D	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(*)

Table 10.4. Browse subnet example 4
Subnet Browse Master List
Subnet1 N1_C 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(*)
Subnet2 N2_B 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(*)
Subnet3 N3_D 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(*)

Subnet	Browse Master	List
Subnet1	N1_C	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()
Subnet2	N2_B	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(*)
Subnet3	N3_D	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(*)

Servers with a (*) after them are non-authoritative names.

@@ -936,11 +883,11 @@ If either router R1 or R2 fails the following will occur: 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. -

Common Errors

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. -

How can one flush the Samba NetBIOS name cache without restarting Samba?

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 @@ -950,8 +897,11 @@ want to clear a rogue machine from the list then every machine on the network wi 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). -

My client reports "This server is not configured to list shared resources"

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. -

See also guest account in the smb.conf man page.

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+
See also guest account in the smb.conf man page.
I get an Unable to browse the network error
This error can have multiple causes:
There is no local master browser. Configure nmbd + or any other machine to serve as local master browser.
You can not log onto the machine that is the local master + browser. Can you logon to it as guest user?
There is no IP connectivity to the local master browser. + Can you reach it by broadcast?
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