From 3ac50a125e27911ec29f1c637417fa9ae1612a86 Mon Sep 17 00:00:00 2001 From: John Terpstra Date: Mon, 21 Apr 2003 20:00:38 +0000 Subject: Merged the two browsing documents into one. Added locking module to global.ent file. (This used to be commit 1027525be23e7db97677e2ed3e2706d271ad0a0b) --- docs/docbook/global.ent | 7 +- docs/docbook/projdoc/Browsing-Quickguide.sgml | 416 -------- docs/docbook/projdoc/Browsing.sgml | 807 ---------------- docs/docbook/projdoc/NetworkBrowsing.sgml | 1288 +++++++++++++++++++++++++ docs/docbook/projdoc/samba-doc.sgml | 3 +- 5 files changed, 1292 insertions(+), 1229 deletions(-) delete mode 100644 docs/docbook/projdoc/Browsing-Quickguide.sgml delete mode 100644 docs/docbook/projdoc/Browsing.sgml create mode 100644 docs/docbook/projdoc/NetworkBrowsing.sgml (limited to 'docs') diff --git a/docs/docbook/global.ent b/docs/docbook/global.ent index c69b72d8a6..dcef1084d6 100644 --- a/docs/docbook/global.ent +++ b/docs/docbook/global.ent @@ -407,8 +407,7 @@ an Active Directory environment. - - + @@ -451,8 +450,7 @@ an Active Directory environment. - - + @@ -463,6 +461,7 @@ an Active Directory environment. + diff --git a/docs/docbook/projdoc/Browsing-Quickguide.sgml b/docs/docbook/projdoc/Browsing-Quickguide.sgml deleted file mode 100644 index d8df57dcb9..0000000000 --- a/docs/docbook/projdoc/Browsing-Quickguide.sgml +++ /dev/null @@ -1,416 +0,0 @@ - - - &author.jht; - July 5, 1998 - Updated: March 15, 2003 - - -Quick Cross Subnet Browsing / Cross Workgroup Browsing guide - - -This document should be read in conjunction with Browsing and may -be taken as the 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 NOT involved in browse list handling -except by way of name to address mapping. - - - -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. - - - - -Discussion - - -Firstly, all MS Windows networking is based on SMB (Server Message -Block) based messaging. SMB messaging may be implemented using NetBIOS or -without NetBIOS. Samba implements NetBIOS 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 -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 -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 -get cross segment browsing to work is by using the -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. - - - -As of Samba 3 WINS replication is being worked on. The bulk of the code has -been committed, but it still needs maturation. - - - -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 -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). - - - -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. - - - - - -How browsing functions and how to deploy stable and -dependable browsing using Samba - - - -As stated above, MS Windows machines register their NetBIOS names -(i.e.: the machine name for each service type in operation) on start -up. Also, as stated above, 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. - - - -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 -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 -and thus WINS allows name resolution to function across routed networks. - - - -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. - - - -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. - - - -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 -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 -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. - - - - - -Use of the <command>Remote Announce</command> 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_ - - 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 -or the broadcst 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. - - - -WORKGROUP -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. - - - - - - - - -Use of the <command>Remote Browse Sync</command> 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 -Samba LMB. It works ONLY if the Samba server that has this option is -simultaneously the LMB on it's 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. - - - - - -Use of WINS - - -Use of WINS (either Samba WINS _or_ MS Windows NT Server WINS) is highly -recommended. Every NetBIOS machine registers it's name together with a -name_type value for each of of several types of service it has available. -eg: It registers it's name directly as a unique (the type 0x03) name. -It also registers it's 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. - - - -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). - - - -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 _or_ via statically configured -lmhosts files that must reside on all clients in the -absence of WINS. - - - -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. - - - -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. - - - -To configure Samba as a WINS server just add -wins support = yes to the smb.conf -file [globals] 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. - - - -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! - - - -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. - - - - - - -Do NOT use more than one (1) protocol on MS Windows machines - - -A very common cause of browsing problems results from installing more than -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 -Windows NT will be biased so that the most suitable machine will predictably -win and thus retain it's role. - - - -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. - - - -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. - - - -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. - - - -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 - -_or_ - -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 -to implement the gethostbyname() function call. This is normally -controlled by /etc/host.conf, /etc/nsswitch.conf and /etc/resolv.conf. - - - diff --git a/docs/docbook/projdoc/Browsing.sgml b/docs/docbook/projdoc/Browsing.sgml deleted file mode 100644 index ca2f6dc57b..0000000000 --- a/docs/docbook/projdoc/Browsing.sgml +++ /dev/null @@ -1,807 +0,0 @@ - - - - - Samba Team - - - - (5 July 1998) - - -Improved browsing in samba - - -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 -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. - - - -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. - - - -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 -for samba to support domain logons and scripts is now available. - - - -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. - - - -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. - - - -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. - - - -To get browsing to work you need to run nmbd as usual, but will need -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 -&smb.conf; man page. - - - - -Problem resolution - - -If something doesn't work then hopefully the log.nmb 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. - - - -Note that if it doesn't work for you, then you should still be able to -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 -IPC$ connection that lists the shares is done as guest, and thus you must -have a valid guest account. - - - -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. - - - -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. - - - -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. - - - -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 &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) - - - - -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 simplicities 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. - - - -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. - - - -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. - - - -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'. - - - -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). - - - - -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. - - - -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 registerd by the Domain master -browser (N1_C) with the WINS server as soon as it was booted. - - - -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 : - - - - -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. - - - -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. - - - - -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 -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 -server entries. Finally - and as a steady state (if no machines -are removed or shut off) the browse lists will look like : - - - - -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. - - - -If either router R1 or R2 fails the following will occur: - - - - - - 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. - - - - - - Attempts to connect to these inaccessible computers will fail, but the - names will not be removed from the network neighbourhood lists. - - - - - - 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. - - - - - - - -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 -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 -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 -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 -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. - - - -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 "Primary WINS Server" field of -the "Control Panel->Network->Protocols->TCP->WINS Server" 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 [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. - - - -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 -nmbd will fail to start. - - - -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. - - - - - -Setting up Browsing in a WORKGROUP - - -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 presense 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 -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. - - - -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 [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. - - - -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 -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 Browsing in a DOMAIN - - -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 -things will break if a Samba server registers the Domain master -browser NetBIOS name (DOMAIN<1B>) -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 -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 -below. - - - -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 [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 - - -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 -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 -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 -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 -"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 -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 -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. - - - - - -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 -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 -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 -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 -using a WINS server to resolve NetBIOS names. If your clients are only -using broadcasting to resolve NetBIOS names, then two things will occur: - - - - - - your local master browsers will be unable to find a domain master - browser, as it will only be looking on the local subnet. - - - - - - 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. - - - - - -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 - as its domain master browser. - - - - - - 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. - - - - - - - -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. - - - diff --git a/docs/docbook/projdoc/NetworkBrowsing.sgml b/docs/docbook/projdoc/NetworkBrowsing.sgml new file mode 100644 index 0000000000..c4b6a07777 --- /dev/null +++ b/docs/docbook/projdoc/NetworkBrowsing.sgml @@ -0,0 +1,1288 @@ + + + &author.jht; + July 5, 1998 + Updated: March 15, 2003 + + +Samba / MS Windows Network Browsing Guide + + +This document contains detailed informataion 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 +NOT involved in browse list handling except by way of name to address resolution. + + + +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. + + + +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 + + + +The samba application that controls/manages 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 + + + +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 is based on SMB (Server Message +Block) based messaging. SMB messaging may be implemented using NetBIOS or +without NetBIOS. Samba implements NetBIOS 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 +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 +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 +get cross segment browsing to work is by using the +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. + + + +As of Samba 3 WINS replication is being worked on. The bulk of the code has +been committed, but it still needs maturation. + + + +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 +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). + + + +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. + + + + + +How Browsing Functions + + +As stated above, MS Windows machines register their NetBIOS names +(ie: the machine name for each service type in operation) on start +up. Also, as stated above, 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. + + + +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 +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 +and thus WINS allows name resolution to function across routed networks. + + + +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. + + + +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. + + + +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 +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 +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 Browsing in a WORKGROUP + + +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 presense 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 +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. + + + +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 [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. + + + +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 +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 Browsing in a DOMAIN + + +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 +things will break if a Samba server registers the Domain master +browser NetBIOS name (DOMAIN<1B>) +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 +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 +below. + + + +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 [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 + + +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 +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 +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 +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 +"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 +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 +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. + + + + + +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 +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 +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 +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 +using a WINS server to resolve NetBIOS names. If your clients are only +using broadcasting to resolve NetBIOS names, then two things will occur: + + + + + + your local master browsers will be unable to find a domain master + browser, as it will only be looking on the local subnet. + + + + + + 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. + + + + + +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 + as its domain master browser. + + + + + + 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. + + + + + + + +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 <command>Remote Announce</command> 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_ + + 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 +or the broadcst 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. + + + +WORKGROUP +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. + + + + + + + + +Use of the <command>Remote Browse Sync</command> 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 +Samba LMB. It works ONLY if the Samba server that has this option is +simultaneously the LMB on it's 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 +recommended. Every NetBIOS machine registers it's name together with a +name_type value for each of of several types of service it has available. +eg: It registers it's name directly as a unique (the type 0x03) name. +It also registers it's 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. + + + +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). + + + +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 _or_ via statically configured +lmhosts files that must reside on all clients in the +absence of WINS. + + + +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. + + + +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. + + + +To configure Samba as a WINS server just add +wins support = yes to the smb.conf +file [globals] 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. + + + +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 +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 +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 +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 +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. + + + +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 "Primary WINS Server" field of +the "Control Panel->Network->Protocols->TCP->WINS Server" 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 [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. + + + +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 +nmbd will fail to start. + + + +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. + + + + + +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 + + +The following hints should be carefully considered as they are stumbling points +for many new network administrators. + + + +Windows Networking Protocols + + +Do NOT use more than one (1) protocol on MS Windows machines + + + +A very common cause of browsing problems results from installing more than +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 +Windows NT will be biased so that the most suitable machine will predictably +win and thus retain it's role. + + + +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. + + + +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. + + + +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. + + + +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 + +_or_ + +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 +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 +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. + + + +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. + + + +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 +for samba to support domain logons and scripts is now available. + + + +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. + + + +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. + + + +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. + + + +To get browsing to work you need to run nmbd as usual, but will need +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 +&smb.conf; man page. + + + + +Problem resolution + + +If something doesn't work then hopefully the log.nmb 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. + + + +Note that if it doesn't work for you, then you should still be able to +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 +IPC$ connection that lists the shares is done as guest, and thus you must +have a valid guest account. + + + +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. + + + +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. + + + +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. + + + +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 &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) + + + + +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 simplicities 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. + + + +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. + + + +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. + + + +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'. + + + +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). + + + + +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. + + + +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 registerd by the Domain master +browser (N1_C) with the WINS server as soon as it was booted. + + + +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 : + + + + +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. + + + +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. + + + + +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 +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 +server entries. Finally - and as a steady state (if no machines +are removed or shut off) the browse lists will look like : + + + + +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. + + + +If either router R1 or R2 fails the following will occur: + + + + + + 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. + + + + + + Attempts to connect to these inaccessible computers will fail, but the + names will not be removed from the network neighbourhood lists. + + + + + + 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. + + + + + + + + diff --git a/docs/docbook/projdoc/samba-doc.sgml b/docs/docbook/projdoc/samba-doc.sgml index a0fc27fcb0..5c3793a1ba 100644 --- a/docs/docbook/projdoc/samba-doc.sgml +++ b/docs/docbook/projdoc/samba-doc.sgml @@ -50,7 +50,7 @@ PLEASE read this. &IntroSMB; &UNIX-INSTALL; -&BROWSING-Quick; +&NetworkBrowsing; &Passdb; @@ -90,7 +90,6 @@ for various environments. &VFS; &MS-Dfs-Setup; &IntegratingWithWindows; -&BROWSING; &SecuringSamba; &unicode; &locking; -- cgit