OVERVIEW:
=========
SMB networking provides a mechanism by which clients can access a list
-of machines that are available within the network. This list is called
-the browse list and is heavily used by all SMB clients. Configuration
+of machines that are available within the network. This list is called
+the browse list and is heavily used by all SMB clients. Configuration
of SMB browsing has been problematic for some Samba users, hence this
document.
BROWSING
========
-Samba now fully supports browsing. The browsing is supported by nmbd
+Samba now fully supports browsing. The browsing is supported by nmbd
and is also controlled by options in the smb.conf file (see smb.conf(5)).
Samba can act as a local browse master for a workgroup and the ability
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.
+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.
[Note that nmbd can be configured as a WINS server, but it is not
necessary to specifically use samba as your WINS server. NTAS can
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.
+example. See "remote announce" in the smb.conf man page.
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
+help you track down the problem. Try a debug level of 2 or 3 for
finding problems.
Note that if it doesn't work for you, then you should still be able to
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$
+"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.
Also, a lot of people are getting bitten by the problem of too many
-parameters on the command line of nmbd in inetd.conf. This trick is to
+parameters on the command line of nmbd in inetd.conf. This trick is to
not use spaces between the option and the parameter (eg: -d2 instead
-of -d 2), and to not use the -B and -N options. New versions of nmbd
+of -d 2), and to not use the -B and -N options. New versions of nmbd
are now far more likely to correctly find your broadcast and network
addess, so in most cases these aren't needed.
netmask or IP address is wrong (specified with the "interfaces" option
in smb.conf)
+
BROWSING ACROSS SUBNETS
=======================
With the release of Samba 1.9.17(alpha1 and above) 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
+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
+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
+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
+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
+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.
=====================================
Cross subnet browsing is a complicated dance, containing multiple
-moving parts. It has taken Microsoft several years to get the code
+moving parts. It has taken Microsoft several years to get the code
that achieves this correct, and Samba lags behind in some areas.
However, with the 1.9.17 release, Samba is capable of cross subnet
browsing when configured correctly.
(WINS)
Consisting of 3 subnets (1, 2, 3) conneted 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
+(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
+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
+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
+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
+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
+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
+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
+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'.
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
+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
+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
+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
+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
+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
+request to the sender of that packet. After both synchronizations
are done the browse lists look like :
Subnet Browse Master List
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
+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
+subnet 2. After N3_D has synchronized with N1_C and vica-versa
the browse lists look like.
Subnet Browse Master List
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
+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
3) 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
+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
+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 previous to 1.9.17 had this parameter default to
-yes. If you have any older versions of Samba on your network it is
+yes. If you have any older versions of Samba on your network it is
strongly suggested you upgrade to 1.9.17 or above, 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
+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
+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
+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
+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"
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
+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
+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 :
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
+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
+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
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
+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
+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 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 (although the same Samba server can act as Domain
-master browser for multiple workgroup names). To set up a Samba
-server as a domain master browser set the following option in the
-[global] section of the smb.conf file :
+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
+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
Next, you should ensure that each of the subnets contains a
machine that can act as a local master browser for the
-workgroup. Any NT machine should be able to do this, as will
+workgroup. Any NT machine should be able to do this, as will
Windows 95 machines (although these tend to get rebooted more
-often, so it's not such a good idea to use these). To make a
+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 :
master browser.
The "local master" parameter allows Samba to act as a local master
-browser. The "preferred master" causes nmbd to force a browser
+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.
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
+described. To make a Samba server a local master browser set
the following options in the [global] section of the smb.conf
file :
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
+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"
below.
==============================
Who becomes the "master browser" is determined by an election process
-using broadcasts. Each election packet contains a number of parameters
+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
+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
+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 NTAS. A
+A "os level" of 2 would make it beat WfWg and Win95, but not NTAS. A
NTAS domain controller uses level 32.
The maximum os level is 255
==============================
The domain master is responsible for collating the browse lists of
-multiple subnets so that browsing can occur between subnets. You can
+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.
+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.
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.
+ 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
+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
+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. See smb.conf(5) for details.
+option in smb.conf to configure them. See smb.conf(5) for details.
git.samba.org / tprouty / samba.git / commitdiff