Chapter 10. Samba / MS Windows Network Browsing Guide

Date: Tue, 1 Jul 2003 22:58:52 +0000 Subject: regenerate docs (This used to be commit cc02d3bc170fe5c8c4474156edb6c83720a47aa0) --- docs/htmldocs/NetworkBrowsing.html | 369 ++++++++++++++++++++----------------- 1 file changed, 196 insertions(+), 173 deletions(-) (limited to 'docs/htmldocs/NetworkBrowsing.html') diff --git a/docs/htmldocs/NetworkBrowsing.html b/docs/htmldocs/NetworkBrowsing.html index c3805ebe60..eb4d9858ca 100644 --- a/docs/htmldocs/NetworkBrowsing.html +++ b/docs/htmldocs/NetworkBrowsing.html @@ -1,8 +1,7 @@ - -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>

July 5, 1998

Updated: April 21, 2003

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 addesses. WINS is +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.

Note

MS Windows 2000 and later can be configured to operate with NO NetBIOS @@ -10,15 +9,15 @@ 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 it's fickle -nature was just par for the course. For those who never quite managed to tame it's -lusty features NetBIOS is like Paterson's Curse. +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.

For those not familiar with botanical problems in Australia: Paterson's curse, Echium plantagineum, was introduced to Australia from Europe during the mid-nineteenth @@ -28,7 +27,7 @@ ability to germinate at any time of year, given the right conditions, are some o features which make it such a persistent weed.

In this chapter we explore vital aspects of SMB (Server Message Block) networking with -a particular focus on SMB as implmented through running NetBIOS (Network Basic +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. @@ -43,7 +42,7 @@ support for NetBIOS, in which case WINS is of no relevance. Samba-3 supports thi

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. @@ -51,7 +50,7 @@ clicked, it opens up and shows the shares and printers available on the target s 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

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

 		
@@ -78,18 +77,18 @@ called nmbd. The configuration parameters involved in
 		* wins support
 		  wins hook

-For Samba the WINS Server and WINS Support are mutually exclusive options. Those marked with +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

+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 are intent on phasing out NetBIOS +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. +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 @@ -98,7 +97,7 @@ to remote network segments via unicast UDP. Similarly, the 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 +Secondly, in those networks where Samba is the only SMB server technology, wherever possible nmbd 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 @@ -113,9 +112,9 @@ the use of the remote announce and the 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. +of one of the Samba-3 release series.

-Right now samba WINS does not support MS-WINS replication. This means that +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 @@ -130,7 +129,7 @@ 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 @@ -159,14 +158,14 @@ force register with a Dynamic DNS server in Windows 200x / XP using: ipconfig /registerdns

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 +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.

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 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 @@ -186,9 +185,9 @@ The following are some of the default service records that Active Directory requ Entry used by MS Windows clients to locate machines using the Global Unique Identifier.

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

- Used by MS Windows clients to locate site configuration dependant + 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 @@ -196,11 +195,11 @@ 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.

-In the case where there is no WINS server all name registrations as +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 +which the Samba server name may be forcibly injected into the browse list of a remote MS Windows network (using the remote announce parameter).

@@ -229,7 +228,7 @@ 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.

-Samba supports a feature that allows forced synchonisation +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. This causes Samba to contact the local master browser on a remote network and @@ -243,7 +242,7 @@ 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* @@ -253,7 +252,7 @@ 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 presense of a domain master browser that makes +subnet. It is the presence of a domain master browser that makes cross subnet browsing possible for a workgroup.

In an WORKGROUP environment the domain master browser must be a @@ -261,22 +260,22 @@ 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 [global] section of the smb.conf file : -

+

+
 	domain master = yes
-

-
+

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 [global] section of the smb.conf file : -

+

+
 	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.

@@ -288,14 +287,14 @@ 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 [global] section of the smb.conf file : -

+

+
 	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. @@ -310,18 +309,18 @@ be the local master browser then you can disable Samba from 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

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 -name is also the Domain master browser for that name, and many +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 (DOMAIN<1B>) with WINS instead of the PDC. @@ -331,20 +330,20 @@ 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 of the smb.conf file : -

+

+
 	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 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 -Forcing samba to be the master browser +more details on this see the section +Forcing Samba to be the master browser below.

If you have Windows NT machines that are members of the domain @@ -353,14 +352,14 @@ you can disable Samba from taking part in browser elections and 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
-

-

Forcing samba to be the master

Forcing Samba to be the master

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 @@ -375,48 +374,48 @@ samba systems!) 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 +If you want Samba to force an election on startup, then set the 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 +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 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 +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 +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.

-It is possible to configure two samba servers to attempt to become +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 +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 +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

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 workgroup that has the same name as an NT Domain.

-When samba is the domain master and the master browser it will listen +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.

-If you want samba to be the domain master then I suggest you also set +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 +preferred master to yes, to get Samba to force an election on startup.

-Note that all your servers (including samba) and clients should be +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:

@@ -427,11 +426,11 @@ using broadcasting to resolve NetBIOS names, then two things will occur: a user attempts to access a host in that list, it will be unable to resolve the NetBIOS name of that host.

-If, however, both samba and your clients are using a WINS server, then: +If, however, both Samba and your clients are using a WINS server, then:

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 + 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.
when a client receives a domain-wide browse list, and a user attempts @@ -439,37 +438,37 @@ 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 option in smb.conf to configure them. -

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] ...
-

-_or_
-+

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

+

where: -

a.b.c.d and + a.b.c.d and e.f.g.h is either the LMB (Local Master Browser) IP address -or the broadcst address of the remote network. +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 +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. WORKGROUP is optional and can be either our own workgroup @@ -478,28 +477,28 @@ 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. - -

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 it's NetBIOS name list with our +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 it's network segment. -

+simultaneously the LMB on its network segment. +

The syntax of the remote browse sync parameter is: -

+
 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 +

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 of several types of service it has available. +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 +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.

@@ -514,7 +513,7 @@ 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 _or_ via statically configured +information can only be provided via WINS or via statically configured lmhosts files that must reside on all clients in the absence of WINS.

@@ -545,16 +544,16 @@ 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 -

+

+
 	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 @@ -563,7 +562,7 @@ least set the parameter to 'no' on all these machines. 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 +You should set up only ONE WINS server. Do NOT set the wins support = yes option on more than one Samba server.

@@ -571,7 +570,7 @@ 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 -refuse to document these replication protocols Samba cannot currently +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 @@ -586,11 +585,11 @@ the Control Panel->Network->Protocols->TCP->W 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>
-

-
+

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

@@ -605,22 +604,45 @@ 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

-New to Samba-3 is a tool called winsedit that may be used to add -static WINS entries to the WINS database. This tool can be used also to modify entries -existing in the WINS database. -

-The development of the winsedit tool was made necessary due to the migration -of the older style wins.dat file into a new tdb binary backend data store. -

Helpful Hints

Static WINS Entries

+Adding static entries to your Samba-3 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. +

+Entries in wins.dat take the form of + +

+"NAME#TYPE" TTL ADDRESS+ FLAGS
+

+ +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. +

+A typical dynamic entry looks like: +

+"MADMAN#03" 1055298378 192.168.1.2 66R
+

+ +To make it static, all that has to be done is set the TTL to 0: + +

+"MADMAN#03" 0 192.168.1.2 66R
+

+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 @@ -628,7 +650,7 @@ one protocol on an MS Windows machine.

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 precidence for winning this election process. A machine running Samba or +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.

@@ -650,29 +672,32 @@ 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.

-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.

+are: +

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.

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: -

+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_ -

+or +

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

The default is: -

-name  resolve order = host lmhost wins bcast
-

+name resolve order = host lmhost wins bcast
+

where "host" refers the 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 contains machines that are ready to offer file and/or print services @@ -683,7 +708,7 @@ browsing has been problematic for some Samba users, hence this document.

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 +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. @@ -692,7 +717,7 @@ 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

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 @@ -702,7 +727,7 @@ 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. +both Samba and your clients use a WINS server.

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 @@ -711,11 +736,11 @@ regardless of whether it is NT, Samba or any other type of domain master that is providing this service.

Note

Nmbd can be configured as a WINS server, but it is not -necessary to specifically use samba as your WINS server. MS Windows +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 +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 +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 @@ -727,8 +752,8 @@ 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 smb.conf man page. -

Problem resolution

-If something doesn't work then hopefully the log.nmb file will help +

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 in text form in a file called browse.dat. @@ -752,15 +777,13 @@ 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 been -updated to enable it to support the replication of browse lists -across subnet boundaries. New code and options have been added to -achieve this. This section describes how to set this feature up -in different settings. +

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.

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 +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 @@ -775,16 +798,16 @@ 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
               |          |           |          |           |
@@ -799,8 +822,8 @@ Consider a network set up as follows :
   |     |     |      |               |        |         |           |
  N2_A  N2_B  N2_C   N2_D           N3_A     N3_B      N3_C        N3_D 
                     (WINS)
-

-
+

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 @@ -841,9 +864,9 @@ called 'non-authoritative'. 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

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

Note that at this point all the subnets are separate, no machine is seen across any of the subnets.

@@ -863,11 +886,11 @@ 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 : -

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

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

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

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. @@ -878,24 +901,24 @@ 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(*)

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(*)

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

At this point users looking in their network neighborhood on -subnets 1 or 3 will see all the servers on all sunbets, users 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.

Finally, the local master browser for subnet 2 (N2_B) will sync again -with the domain master browser (N1_C) and will recieve the missing +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(*)

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(*)

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

Synchronizations between the domain master browser and local master browsers will continue to occur, but this should be a steady state situation. @@ -913,13 +936,13 @@ 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 sked on the mailing lists regarding browsing. The majority of browsing +

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?

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 +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 @@ -927,7 +950,7 @@ 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. -- cgit