bionic (8) smbd.8.gz

Provided by: samba_4.7.6+dfsg~ubuntu-0ubuntu2.29_amd64 bug

NAME

       smbd - server to provide SMB/CIFS services to clients

SYNOPSIS

       smbd [-D|--daemon] [-F|--foreground] [-S|--log-stdout] [-i|--interactive] [-V] [-b|--build-options]
        [-d <debug level>] [-l|--log-basename <log directory>] [-p <port number(s)>] [-P <profiling level>]
        [-s <configuration file>] [--no-process-group]

DESCRIPTION

       This program is part of the samba(7) suite.

       smbd is the server daemon that provides filesharing and printing services to Windows clients. The server
       provides filespace and printer services to clients using the SMB (or CIFS) protocol. This is compatible
       with the LanManager protocol, and can service LanManager clients. These include MSCLIENT 3.0 for DOS,
       Windows for Workgroups, Windows 95/98/ME, Windows NT, Windows 2000, OS/2, DAVE for Macintosh, and smbfs
       for Linux.

       An extensive description of the services that the server can provide is given in the man page for the
       configuration file controlling the attributes of those services (see smb.conf(5). This man page will not
       describe the services, but will concentrate on the administrative aspects of running the server.

       Please note that there are significant security implications to running this server, and the smb.conf(5)
       manual page should be regarded as mandatory reading before proceeding with installation.

       A session is created whenever a client requests one. Each client gets a copy of the server for each
       session. This copy then services all connections made by the client during that session. When all
       connections from its client are closed, the copy of the server for that client terminates.

       The configuration file, and any files that it includes, are automatically reloaded every minute, if they
       change. You can force a reload by sending a SIGHUP to the server. Reloading the configuration file will
       not affect connections to any service that is already established. Either the user will have to
       disconnect from the service, or smbd killed and restarted.

OPTIONS

       -D|--daemon
           If specified, this parameter causes the server to operate as a daemon. That is, it detaches itself
           and runs in the background, fielding requests on the appropriate port. Operating the server as a
           daemon is the recommended way of running smbd for servers that provide more than casual use file and
           print services. This switch is assumed if smbd is executed on the command line of a shell.

       -F|--foreground
           If specified, this parameter causes the main smbd process to not daemonize, i.e. double-fork and
           disassociate with the terminal. Child processes are still created as normal to service each
           connection request, but the main process does not exit. This operation mode is suitable for running
           smbd under process supervisors such as supervise and svscan from Daniel J. Bernstein's daemontools
           package, or the AIX process monitor.

       -S|--log-stdout
           If specified, this parameter causes smbd to log to standard output rather than a file.

       -i|--interactive
           If this parameter is specified it causes the server to run "interactively", not as a daemon, even if
           the server is executed on the command line of a shell. Setting this parameter negates the implicit
           daemon mode when run from the command line.  smbd will only accept one connection and terminate. It
           will also log to standard output, as if the -S parameter had been given.

       -d|--debuglevel=level
           level is an integer from 0 to 10. The default value if this parameter is not specified is 0.

           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.

           Note that specifying this parameter here will override the log level parameter in the smb.conf file.

       -V|--version
           Prints the program version number.

       -s|--configfile=<configuration file>
           The file specified contains the configuration details required by the server. The information in this
           file includes server-specific information such as what printcap file to use, as well as descriptions
           of all the services that the server is to provide. See smb.conf for more information. The default
           configuration file name is determined at compile time.

       -l|--log-basename=logdirectory
           Base directory name for log/debug files. The extension ".progname" will be appended (e.g.
           log.smbclient, log.smbd, etc...). The log file is never removed by the client.

       --option=<name>=<value>
           Set the smb.conf(5) option "<name>" to value "<value>" from the command line. This overrides
           compiled-in defaults and options read from the configuration file.

       -?|--help
           Print a summary of command line options.

       --usage
           Display brief usage message.

       --no-process-group
           Do not create a new process group for smbd.

       -b|--build-options
           Prints information about how Samba was built.

       -p|--port<port number(s)>
           port number(s) is a space or comma-separated list of TCP ports smbd should listen on. The default
           value is taken from the ports parameter in smb.conf

           The default ports are 139 (used for SMB over NetBIOS over TCP) and port 445 (used for plain SMB over
           TCP).

       -P|--profiling-level<profiling level>
           profiling level is a number specifying the level of profiling data to be collected. 0 turns off
           profiling, 1 turns on counter profiling only, 2 turns on complete profiling, and 3 resets all
           profiling data.

FILES

       /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.

       /etc/rc
           or whatever initialization 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.

       /etc/services
           If running the server via the meta-daemon inetd, this file must contain a mapping of service name
           (e.g., netbios-ssn) to service port (e.g., 139) and protocol type (e.g., tcp).

       /usr/local/samba/lib/smb.conf
           This is the default location of the smb.conf(5) server configuration file. Other common places that
           systems install this file are /usr/samba/lib/smb.conf and /etc/samba/smb.conf.

           This file describes all the services the server is to make available to clients. See smb.conf(5) for
           more information.

LIMITATIONS

       On some systems smbd cannot change uid back to root after a setuid() call. Such systems are called
       trapdoor uid systems. If you have such a system, you will be unable to connect from a client (such as a
       PC) as two different users at once. Attempts to connect the second user will result in access denied or
       similar.

ENVIRONMENT VARIABLES

       PRINTER
           If no printer name is specified to printable services, most systems will use the value of this
           variable (or lp if this variable is not defined) as the name of the printer to use. This is not
           specific to the server, however.

PAM INTERACTION

       Samba uses PAM for authentication (when presented with a plaintext password), for account checking (is
       this account disabled?) and for session management. The degree too which samba supports PAM is restricted
       by the limitations of the SMB protocol and the obey pam restrictions smb.conf(5) parameter. When this is
       set, the following restrictions apply:

              •   Account Validation: All accesses to a samba server are checked against PAM to see if the
                  account is valid, not disabled and is permitted to login at this time. This also applies to
                  encrypted logins.

              •   Session Management: When not using share level security, users must pass PAM's session checks
                  before access is granted. Note however, that this is bypassed in share level security. Note
                  also that some older pam configuration files may need a line added for session support.

VERSION

       This man page is correct for version 3 of the Samba suite.

DIAGNOSTICS

       Most diagnostics issued by the server are logged in a specified log file. The log file name is specified
       at compile 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. Unfortunately, at the time this man page was created,
       there are too many diagnostics available in the source code 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.

TDB FILES

       Samba stores it's data in several TDB (Trivial Database) files, usually located in /var/lib/samba.

       (*) information persistent across restarts (but not necessarily important to backup).

       account_policy.tdb*
           NT account policy settings such as pw expiration, etc...

       brlock.tdb
           byte range locks

       browse.dat
           browse lists

       gencache.tdb
           generic caching db

       group_mapping.tdb*
           group mapping information

       locking.tdb
           share modes & oplocks

       login_cache.tdb*
           bad pw attempts

       messages.tdb
           Samba messaging system

       netsamlogon_cache.tdb*
           cache of user net_info_3 struct from net_samlogon() request (as a domain member)

       ntdrivers.tdb*
           installed printer drivers

       ntforms.tdb*
           installed printer forms

       ntprinters.tdb*
           installed printer information

       printing/
           directory containing tdb per print queue of cached lpq output

       registry.tdb
           Windows registry skeleton (connect via regedit.exe)

       smbXsrv_session_global.tdb
           session information (e.g. support for 'utmp = yes')

       smbXsrv_tcon_global.tdb
           share connections (used to enforce max connections, etc...)

       smbXsrv_open_global.tdb
           open file handles (used durable handles, etc...)

       share_info.tdb*
           share acls

       winbindd_cache.tdb
           winbindd's cache of user lists, etc...

       winbindd_idmap.tdb*
           winbindd's local idmap db

       wins.dat*
           wins database when 'wins support = yes'

SIGNALS

       Sending the smbd a SIGHUP will cause it to reload its smb.conf configuration file within a short period
       of time.

       To shut down a user's smbd process it is recommended that SIGKILL (-9) NOT be used, except as a last
       resort, as this may leave the shared memory area in an inconsistent state. The safe way to terminate an
       smbd is to send it a SIGTERM (-15) signal and wait for it to die on its own.

       The debug log level of smbd may be raised or lowered using smbcontrol(1) program (SIGUSR[1|2] signals are
       no longer used since Samba 2.2). This is to allow transient problems to be diagnosed, whilst still
       running at a normally low log level.

       Note that as the signal handlers send a debug write, they are not re-entrant in smbd. This you should
       wait until smbd is in a state of waiting for an incoming SMB before issuing them. It is possible to make
       the signal handlers safe by un-blocking the signals before the select call and re-blocking them after,
       however this would affect performance.

SEE ALSO

       hosts_access(5), inetd(8), nmbd(8), smb.conf(5), smbclient(1), testparm(1), and the Internet RFC's
       rfc1001.txt, rfc1002.txt. In addition the CIFS (formerly SMB) specification is available as a link from
       the Web page https://www.samba.org/cifs/.

AUTHOR

       The original Samba software and related utilities were created by Andrew Tridgell. Samba is now developed
       by the Samba Team as an Open Source project similar to the way the Linux kernel is developed.

       The original Samba man pages were written by Karl Auer. The man page sources were converted to YODL
       format (another excellent piece of Open Source software, available at ftp://ftp.icce.rug.nl/pub/unix/)
       and updated for the Samba 2.0 release by Jeremy Allison. The conversion to DocBook for Samba 2.2 was done
       by Gerald Carter. The conversion to DocBook XML 4.2 for Samba 3.0 was done by Alexander Bokovoy.