Man Page for NMBD
nmbd - provide netbios nameserver support to clients
nmbd [ -B broadcast address ] [ -I IP address ] [ -D ] [ -C comment string ] [ -G group name ] [ -H netbios hosts file ] [ -L netbios name ] [ -M workgroup name ] [ -N net- mask ] [ -P ] [ -R ] [ -b ] [ -S ] [ -d debuglevel ] [ -l log basename ] -n netbios name ] [ -O socket options ] [ -p port number ] [ -T browse interval ]
This program is part of the Samba suite. nmbd is a server that understands and can reply to netbios name service requests, like those produced by LanManager clients. LanManager clients, when they start up, may wish to locate a LanManager server. That is, they wish to know what IP number a specified host is using. This program simply listens for such requests, and if its own name is specified it will respond with the IP number of the host it is running on. "Its own name" is by default the name of the host it is running on, but this can be overriden with the -n option (see "OPTIONS" below). Using the -S option (see "OPTIONS" below), it can also be instructed to respond with IP information about other hosts, provided they are locatable via the gethostbyname() call, or they are in a netbios hosts file. Nmbd can also be used as a WINS (Windows Internet Name Server) server. It will do this automatically by default. What this basically means is that it will respond to all name requests that it receives that are not broadcasts, as long as it can resolve the name.
-b This toggles support for browsing from WfWg. It defaults to on. -B On some systems, the server is unable to determine the broadcast address to use for name registration requests. If your system has this difficulty, this parameter may be used to specify an appropriate broad- cast address. The address should be given in standard "a.b.c.d" notation. Only use this parameter if you are sure that the server cannot properly determine the proper broadcast address. The default broadcast address is determined by the server at run time. If it encounters difficulty doing so, it makes a guess based on the local IP number. -I On some systems, the server is unable to determine the correct IP address to use. This allows you to override the default choice. -D If specified, this parameter causes the server to oper- ate as a daemon. That is, it detaches itself and runs in the background, fielding requests on the appropriate port. By default, the server will NOT operate as a daemon. -C comment string This allows you to set the "comment string" that is shown next to the machine name in browse listings. A %v will be replaced with the Samba version number. A %h will be replaced with the hostname. It defaults to "Samba %v". -G This option allows you to specify a netbios group (also known as lanmanager domain) that the server should be part of. You may include several of these on the com- mand line if you like. Alternatively you can use the -H option to load a netbios hosts file containing domain names. At startup, unless the -R switch has been used, the server will attempt to register all group names in the hosts file and on the command line (from the -G option). The server will also respond to queries on this name. -H It may be useful in some situations to be able to spec- ify a list of netbios names for which the server should send a reply if queried. This option allows that. The syntax is similar to the standard /etc/hosts file for- mat, but has some extensions. The file contains three columns. Lines beginning with a # are ignored as comments. The first column is an IP address, or a hostname. If it is a hostname then it is interpreted as the IP address returned by gethostby- name() when read. Any IP address of 0.0.0.0 will be interpreted as the servers own IP address. The second column is a netbios name. This is the name that the server will respond to. It must be less than 20 characters long. The third column is optional, and is intended for flags. Currently the only flags supported are G, S and M. A G indicates that the name is a group (also known as domain) name. At startup all groups known to the server (either from this file or from the -G option) are registered on the network (unless the -R option has been selected). A S means that the specified address is a broadcast address of a network that you want people to be able to browse you from. Nmbd will search for a master browser in that domain and will send host announcements to that machine, informing it that the specifed somain is available. A M means that this name is the default netbios name for this machine. This has the same affect as specify- ing the -n option to nmbd. After startup the server waits for queries, and will answer queries to any name known to it. This includes all names in the netbios hosts file (if any), it's own name, and any names given with the -G option. The primary intention of the -H option is to allow a mapping from netbios names to internet domain names, and to allow the specification of groups that the server should be part of. Example: # This is a sample netbios hosts file # DO NOT USE THIS FILE AS-IS # YOU MAY INCONVENIENCE THE OWNERS OF THESE IPs # if you want to include a name with a space in it then # use double quotes. # first put ourselves in the group LANGROUP 0.0.0.0 LANGROUP G # next add a netbios alias for a faraway host arvidsjaur.anu.edu.au ARVIDSJAUR # finally put in an IP for a hard to find host 22.214.171.124 FREDDY # now we want another subnet to be able to browse # us in the workgroup UNIXSERV 192.0.2.255 UNIXSERV S -M workgroup name If this parameter is given, the server will look for a master browser for the specified workgroup name, report success or failure, then exit. If successful, the IP address of the name located will be reported. If you use the workgroup name "-" then nmbd will search for a master browser for any workgroup by using the name __MSBROWSE__. This option is meant to be used interactively on the command line, not as a daemon or in inetd. -L netbios name If this parameter is given, the server will look up the specified netbios name, report success or failure, then exit. If successful, the IP address of the name located will be reported. This is useful for determining whether a netbios name is in use on a subnet and for matching IP addresses to netbios names. This option is meant to be used interactively on the command line, not as a daemon or in inetd. Use of this parameter causes options -D , -P , -R and -n to be ignored. By default, the server will NOT do this. -N On some systems, the server is unable to determine the netmask. If your system has this difficulty, this parameter may be used to specify an appropriate net- mask. The mask should be given in standard "a.b.c.d" notation. Only use this parameter if you are sure that the server cannot properly determine the proper netmask. The default netmask is determined by the server at run time. If it encounters difficulty doing so, it makes a guess based on the local IP number. -P If specified, this parameter causes the server to oper- ate passively. That is, it continues to field requests, but will not respond. By default, the server will NOT operate passively. -S If specified, this parameter causes the server to respond to broadcast name queries for hosts that can be found with the gethostbyname() call (which normally goes to NIS or DNS). It will NOT respond if the host being queried is on the same subnet as the server. This is useful so clients can connect to servers to which they cannot broadcast. By default, the server will NOT respond to any broad- cast queries other than it's own name. -d debuglevel debuglevel is an integer from 0 to 5. The default value if this parameter is not specified is zero. The higher this value, the more detail will be logged to the log files about the activities of the server. At level 0, only critical errors and serious warnings will be logged. Level 1 is a reasonable level for day to day running - it generates a small amount of information about operations carried out. Levels above 1 will generate considerable amounts of log data, and should only be used when investigating a problem. Levels above 3 are designed for use only by developers and generate HUGE amounts of log data, most of which is extremely cryptic. -l log file If specified, logfile specifies a base filename into which operational data from the running server will be logged. The default base name is specified at compile time. The base name is used to generate actual log file names. For example, if the name specified was "log", the following files would be used for log data: log.nmb (containing debugging information) log.nmb.in (containing inbound transaction data) log.nmb.out (containing outbound transaction data) The log files generated are never removed by the server. -n netbios name This parameter tells the server what netbios name to respond with when queried. The same name is also regis- tered on startup unless the -R parameter was specified. The default netbios name used if this parameter is not specified is the name of the host on which the server is running. -O socket options See the socket options section of smb_conf(5) for details -p port number port number is a positive integer value. The default value if this parameter is not specified is 137. This number is the port number that will be used when making connections to the server from client software. The standard (well-known) port number for the server is 137, hence the default. If you wish to run the server as an ordinary user rather than as root, most systems will require you to use a port number greater than 1024 - ask your system administrator for help if you are in this situation. Note that the name server uses UDP, not TCP! This parameter is not normally specified except in the above situation. -T browse interval This sets the number of seconds between browse announcements. It defaults to 60 seconds. The minimum value is 10 seconds.
/etc/inetd.conf If the server is to be run by the inetd meta-daemon, this file must contain suitable startup information for the meta-daemon. See the section "INSTALLATION" below. /etc/rc.d/rc.inet2 (or whatever initialisation script your system uses) If running the server as a daemon at startup, this file will need to contain an appropriate startup sequence for the server. See the section "Installation" below. /etc/services If running the server via the meta-daemon inetd, this file must contain a mapping of service name (eg., net- bios-ns) to service port (eg., 137) and protocol type (eg., udp). See the section "INSTALLATION" below.
The location of the server and its support files is a mat- ter for individual system administrators. The following are thus suggestions only. It is recommended that the server software be installed under the /usr/local hierarchy, in a directory readable by all, writeable only by root. The server program itself should be executable by all, as users may wish to run the server themselves (in which case it will of course run with their privileges). The server should NOT be setuid or setgid! The server log files should be put in a directory readable and writable only by root, as the log files may contain sensitive information. The remaining notes will assume the following: nmbd (the server program) installed in /usr/local/smb log files stored in /var/adm/smblogs The server may be run either as a daemon by users or at startup, or it may be run from a meta-daemon such as inetd upon request. If run as a daemon, the server will always be ready, so starting sessions will be faster. If run from a meta-daemon some memory will be saved and utilities such as the tcpd TCP-wrapper may be used for extra security. When you've decided, continue with either "Running the server as a daemon" or "Running the server on request".
RUNNING THE SERVER AS A DAEMON
To run the server as a daemon from the command line, sim- ply put the "-D" option on the command line. There is no need to place an ampersand at the end of the command line - the "-D" option causes the server to detach itself from the tty anyway. Any user can run the server as a daemon (execute permis- sions permitting, of course). This is useful for testing purposes. To ensure that the server is run as a daemon whenever the machine is started, you will need to modify the system startup files. Wherever appropriate (for example, in /etc/rc.d/rc.inet2), insert the following line, substitut- ing values appropriate to your system: /usr/local/smb/nmbd -D -l/var/adm/smblogs/log (The above should appear in your initialisation script as a single line. Depending on your terminal characteris- tics, it may not appear that way in this man page. If the above appears as more than one line, please treat any new- lines or indentation as a single space or TAB character.) If the options used at compile time are appropriate for your system, all parameters except the desired debug level and "-D" may be omitted. See the section on "Options" above.
RUNNING THE SERVER ON REQUEST
If your system uses a meta-daemon such as inetd, you can arrange to have the SMB name server started whenever a process attempts to connect to it. This requires several changes to the startup files on the host machine. If you are experimenting as an ordinary user rather than as root, you will need the assistance of your system administrator to modify the system files. First, ensure that a port is configured in the file /etc/services. The well-known port 137 should be used if possible, though any port may be used. Ensure that a line similar to the following is in /etc/services: netbios-ns 137/udp Note for NIS/YP users: You may need to rebuild the NIS service maps rather than alter your local /etc/services file. Next, put a suitable line in the file /etc/inetd.conf (in the unlikely event that you are using a meta-daemon other than inetd, you are on your own). Note that the first item in this line matches the service name in /etc/services. Substitute appropriate values for your system in this line (see inetd(8)): netbios-ns dgram udp wait root /usr/local/smb/nmbd -l/var/adm/smblogs/log (The above should appear in /etc/inetd.conf as a single line. Depending on your terminal characteristics, it may not appear that way in this man page. If the above appears as more than one line, please treat any newlines or indentation as a single space or TAB character.) Note that there is no need to specify a port number here, even if you are using a non-standard port number.
TESTING THE INSTALLATION
If running the server as a daemon, execute it before pro- ceeding. If using a meta-daemon, either restart the system or kill and restart the meta-daemon. Some versions of inetd will reread their configuration tables if they receive a HUP signal. To test whether the name server is running, start up a client on a different machine and see whether the desired name is now present. Alternatively, run the nameserver on a different machine specifying "-L netbiosname", where "netbiosname" is the name you have configured the test server to respond with. The command should respond with success, and the IP number of the machine using the speci- fied netbios name. You may need the -B parameter on some systems. See the README file for more information on test- ing nmbd.
This man page is (mostly) correct for version 1.9.00 of the Samba suite, plus some of the recent patches to it. These notes will necessarily lag behind development of the software, so it is possible that your version of the server has extensions or parameter semantics that differ from or are not covered by this man page. Please notify these to the address below for rectification.
[This section under construction] Most diagnostics issued by the server are logged in the specified log file. The log file name is specified at com- pile time, but may be overridden on the command line. The number and nature of diagnostics available depends on the debug level used by the server. If you have problems, set the debug level to 3 and peruse the log files. Most messages are reasonably self-explanatory. Unfortu- nately, at time of creation of this man page the source code is still too fluid to warrant describing each and every diagnostic. At this stage your best bet is still to grep the source code and inspect the conditions that gave rise to the diagnostics you are seeing.
The original Samba software and related utilities were created by Andrew Tridgell (Andrew.). Andrew is also the Keeper of the Source for this project. This man page written by Karl Auer (Karl.) See smb_conf(5) for a full list of contributors and details on how to submit bug reports, comments etc.
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