smbd



SMBD(8)                                                                SMBD(8)




NAME

       smbd - server to provide SMB/CIFS services to clients


SYNOPSIS

       smbd [-D] [-F] [-S] [-i] [-h] [-V] [-b] [-d <debug level>]
            [-l <log directory>] [-p <port number(s)>] [-O <socket option>]
            [-s <configuration file>]



DESCRIPTION

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


       smbd  is  the server daemon that provides filesharing and printing ser-
       vices to Windows clients. The server  provides  filespace  and  printer
       services  to clients using the SMB (or CIFS) protocol. This is compati-
       ble 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  at-
       tributes of those services (see smb.conf(5). This man page will not de-
       scribe 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  con-
       nections  made  by the client during that session. When all connections
       from its client are closed, the copy of the server for that client ter-
       minates.


       The  configuration  file, and any files that it includes, are automati-
       cally 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.  Ei-
       ther  the user will have to disconnect from the service, or smbd killed
       and restarted.



OPTIONS

       -D     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     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 con-
              nection request, but the main process does not exit. This opera-
              tion mode is suitable for runningsmbd under process  supervisors
              such  as supervise and svscan from Daniel J. Bernstein’s daemon-
              tools package, or the AIX process monitor.


       -S     If specified, this parameter causessmbd to log to standard  out-
              put rather than a file.


       -i     If  this parameter is specified it causes the server to run "in-
              teractively", not as a daemon, even if the server is executed on
              the  command line of a shell. Setting this parameter negates the
              implicit deamon mode when run from the command line.  smbd  also
              logs  to standard output, as if the -S parameter had been given.


       -V     Prints the program version number.


       -s <configuration file>
              The file specified contains the configuration  details  required
              by the server. The information in this file includes server-spe-
              cific 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.


       -d|--debug=debuglevel
              debuglevel is an integer from 0 to 10. 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 crit-
              ical 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  pa-
              rameter in the smb.conf file.


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


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


       -b     Prints information about how Samba was built.


       -p <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).



FILES

       /etc/inetd.conf
              If  the  server  is to be run by theinetd 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  configu-
              ration  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 sys-
              tems 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  re-
       stricted  by  the  limitations of the SMB protocol and the obey pam re-
       strictions smb.conf(5) paramater. When this is set, the  following  re-
       strictions apply:


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

       ·  Session Management: When not using share level secuirty, users  must
          pass  PAM’s  session  checks before access is granted. Note however,
          that this is bypassed in share level secuirty. Note also  that  some
          older pam configuration files may need a line added for session sup-
          port.




VERSION

       This man page is correct for version 3.0 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 over-
       ridden 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 avail-
       able in the source code to warrant describing each and  every  diagnos-
       tic.  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  see-
       ing.



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  impor-
       tant to backup).


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


       brlock.tdb
              byte range locks


       browse.dat
              browse lists


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


       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)


       sessionid.tdb
              session information (e.g. support for ’utmp = yes’)


       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 configu-
       ration 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 mem-
       ory 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  smbcon-
       trol(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 untilsmbd 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),  test-
       parm(1),  testprns(1),  and the Internet RFC’srfc1001.txt, rfc1002.txt.
       In addition the CIFS (formerly SMB) specification  is  available  as  a
       link from the Web page http://samba.org/cifs/.



AUTHOR

       The  original  Samba software and related utilities were created by An-
       drew 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 up-
       dated 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 Doc-
       Book XML 4.2 for Samba 3.0 was done by Alexander Bokovoy.




                                                                       SMBD(8)

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