winbindd



WINBINDD(8)                                                        WINBINDD(8)




NAME

       winbindd  -  Name  Service  Switch  daemon  for resolving names from NT
       servers


SYNOPSIS

       winbindd [-F] [-S] [-i] [-Y] [-d <debug level>] [-s <smb config file>]
                [-n]



DESCRIPTION

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


       winbindd  is  a  daemon  that provides a number of services to the Name
       Service Switch capability found in most modern C libraries, to arbitary
       applications via PAM and ntlm_auth and to Samba itself.


       Even  if  winbind is not used for nsswitch, it still provides a service
       to smbd, ntlm_auth and the pam_winbind.so PAM module, by managing  con-
       nections to domain controllers. In this configuraiton the idmap uid and
       idmap gid parameters are not required.  (This  is  known  as  ‘netlogon
       proxy only mode’.)


       The  Name  Service  Switch allows user and system information to be ob-
       tained from different databases services such as NIS or DNS. The  exact
       behaviour can be configured throught the /etc/nsswitch.conf file. Users
       and groups are allocated as they are resolved to a range  of  user  and
       group ids specified by the administrator of the Samba system.


       The service provided by winbindd is called ‘winbind’ and can be used to
       resolve user and group information from a Windows NT server.  The  ser-
       vice  can  also  provide  authentication services via an associated PAM
       module.


       The pam_winbind module supports the auth,  account  and  password  mod-
       ule-types. It should be noted that the account module simply performs a
       getpwnam() to verify that the system can obtain a uid for the user,  as
       the domain controller has already performed access control. If the lib-
       nss_winbind library has  been  correctly  installed,  or  an  alternate
       source of names configured, this should always succeed.


       The  following  nsswitch databases are implemented by the winbindd ser-
       vice:


       hosts  This feature is only available on IRIX. User information  tradi-
              tionally stored in the hosts(5) file and used bygethostbyname(3)
              functions. Names are resolved through  the  WINS  server  or  by
              broadcast.


       passwd User  information traditionally stored in the passwd(5) file and
              used bygetpwent(3) functions.


       group  Group information traditionally stored in the group(5) file  and
              used bygetgrent(3) functions.


       For   example,  the  following  simple  configuration  in  the/etc/nss-
       witch.conf file can be used to initially resolve user and group  infor-
       mation  from  /etc/passwd   and /etc/group and then from the Windows NT
       server.

       passwd:         files winbind
       group:          files winbind
       ## only available on IRIX; Linux users should us libnss_wins.so
       hosts:          files dns winbind



       The following simple configuration in the/etc/nsswitch.conf file can be
       used  to  initially resolve hostnames from /etc/hosts and then from the
       WINS server.

       hosts:         files wins



OPTIONS

       -F     If specified, this parameter causes the main winbindd process to
              not daemonize, i.e. double-fork and disassociate with the termi-
              nal. Child processes are still created as normal to service each
              connection request, but the main process does not exit. This op-
              eration mode is suitable for runningwinbindd under  process  su-
              pervisors  such  as  supervise  and  svscan from Daniel J. Bern-
              stein’s daemontools package, or the AIX process monitor.


       -S     If specified, this parameter causeswinbindd to log  to  standard
              output rather than a file.


       -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.


       -i     Tells  winbindd  to not become a daemon and detach from the cur-
              rent terminal. This option is used by developers  when  interac-
              tive  debugging  of  winbindd  is required.winbindd also logs to
              standard output, as if the -S parameter had been given.


       -n     Disable caching. This means winbindd will always  have  to  wait
              for  a response from the domain controller before it can respond
              to a client and this thus makes things slower. The results  will
              however be more accurate, since results from the cache might not
              be up-to-date. This might also temporarily hang winbindd if  the
              DC doesn’t respond.


       -Y     Single  daemon  mode.  This  means winbindd will run as a single
              process (the mode of operation in Samba 2.2). Winbindd’s default
              behavior  is  to  launch a child process that is responsible for
              updating expired cache entries.



NAME AND ID RESOLUTION

       Users and groups on a Windows NT server  are  assigned  a  security  id
       (SID)  which  is  globally unique when the user or group is created. To
       convert the Windows NT user or group into a unix user or group, a  map-
       ping  between SIDs and unix user and group ids is required. This is one
       of the jobs that  winbindd performs.


       As winbindd users and groups are resolved from a server, user and group
       ids are allocated from a specified range. This is done on a first come,
       first served basis, although all existing  users  and  groups  will  be
       mapped  as  soon  as a client performs a user or group enumeration com-
       mand. The allocated unix ids are stored in a database  file  under  the
       Samba lock directory and will be remembered.


       WARNING: The SID to unix id database is the only location where the us-
       er and group mappings are stored by winbindd. If this file  is  deleted
       or  corrupted, there is no way for winbindd to determine which user and
       group ids correspond to Windows NT user and group rids.


       See the  parameter in smb.conf for options for sharing  this  database,
       such as via LDAP.



CONFIGURATION

       Configuration  of the winbindd daemon is done through configuration pa-
       rameters in the smb.conf(5) file. All parameters should be specified in
       the [global] section of smb.conf.


       ·  winbind separator

       ·  idmap uid

       ·  idmap gid

       ·  idmap backend

       ·  winbind cache time

       ·  winbind enum users

       ·  winbind enum groups

       ·  template homedir

       ·  template shell

       ·  winbind use default domain




EXAMPLE SETUP

       To setup winbindd for user and group lookups plus authentication from a
       domain controller use something like  the  following  setup.  This  was
       tested on a RedHat 6.2 Linux box.


       In /etc/nsswitch.conf put the following:

       passwd:     files winbind
       group:      files winbind



       In /etc/pam.d/* replace the  auth lines with something like this:

       auth       required /lib/security/pam_securetty.so
       auth       required /lib/security/pam_nologin.so
       auth       sufficient    /lib/security/pam_winbind.so
       auth       required     /lib/security/pam_pwdb.so use_first_pass shadow nullok



       Note  in  particular  the  use  of  the  sufficient   keyword  and  the
       use_first_pass keyword.


       Now replace the account lines with this:


       account required /lib/security/pam_winbind.so


       The next step is to join the domain. To do that use thenet program like
       this:


       net join -S PDC -U Administrator


       The username after the -U can be any Domain user that has administrator
       privileges on the machine. Substitute the name or IP of  your  PDC  for
       "PDC".


       Next  copy libnss_winbind.so to/lib and pam_winbind.so  to /lib/securi-
       ty. A symbolic  link  needs  to  be  made  from  /lib/libnss_winbind.so
       to/lib/libnss_winbind.so.2.  If you are using an older version of glibc
       then the target of the link should be/lib/libnss_winbind.so.1.


       Finally, setup a smb.conf(5) containing directives like the following:

       [global]
            winbind separator = +
               winbind cache time = 10
               template shell = /bin/bash
               template homedir = /home/%D/%U
               idmap uid = 10000-20000
               idmap gid = 10000-20000
               workgroup = DOMAIN
               security = domain
               password server = *



       Now start winbindd and  you  should  find  that  your  user  and  group
       database  is expanded to include your NT users and groups, and that you
       can login to your unix box as a domain user, using the DOMAIN+user syn-
       tax  for  the  username. You may wish to use the commands getent passwd
       and getent group  to confirm the correct operation of winbindd.



NOTES

       The following notes are useful when configuring and running winbindd:


       nmbd(8) must be running on the local machine for winbindd to work.


       PAM is really easy to misconfigure. Make sure you know what you are do-
       ing  when  modifying  PAM configuration files. It is possible to set up
       PAM such that you can no longer log into your system.


       If more than one UNIX machine is running winbindd, then in general  the
       user and groups ids allocated by winbindd will not be the same. The us-
       er and group ids will only be valid for the  local  machine,  unless  a
       shared  is configured.


       If  the  the  Windows  NT SID to UNIX user and group id mapping file is
       damaged or destroyed then the mappings will be lost.



SIGNALS

       The following signals can be used to manipulate thewinbindd daemon.


       SIGHUP Reload the smb.conf(5) file and apply any parameter  changes  to
              the  running  version  of  winbindd. This signal also clears any
              cached user and group information. The  list  of  other  domains
              trusted by winbindd is also reloaded.


       SIGUSR2
              The SIGUSR2 signal will cause  winbindd to write status informa-
              tion to the winbind log file.

              Log files are stored in the filename specified by the  log  file
              parameter.



FILES

       /etc/nsswitch.conf(5)
              Name service switch configuration file.


       /tmp/.winbindd/pipe
              The  UNIX  pipe over which clients communicate with the winbindd
              program. For security reasons, the winbind client will only  at-
              tempt  to  connect to the winbindd daemon if both the /tmp/.win-
              bindd directory and /tmp/.winbindd/pipe file are owned by  root.


       $LOCKDIR/winbindd_privileged/pipe
              The  UNIX  pipe over which ’privileged’ clients communicate with
              the winbindd program. For security reasons, access to some  win-
              bindd  functions  - like those needed by the ntlm_auth utility -
              is restricted. By default, only users in the ’root’  group  will
              get  this access, however the administrator may change the group
              permissions on $LOCKDIR/winbindd_privileged  to  allow  programs
              like ’squid’ to use ntlm_auth. Note that the winbind client will
              only attempt to connect to  the  winbindd  daemon  if  both  the
              $LOCKDIR/winbindd_privileged    directory    and   $LOCKDIR/win-
              bindd_privileged/pipe file are owned by root.


       /lib/libnss_winbind.so.X
              Implementation of name service switch library.


       $LOCKDIR/winbindd_idmap.tdb
              Storage for the Windows NT rid to UNIX  user/group  id  mapping.
              The lock directory is specified when Samba is initially compiled
              using the --with-lockdir option. This directory  is  by  default
              /usr/local/samba/var/locks .


       $LOCKDIR/winbindd_cache.tdb
              Storage for cached user and group information.



VERSION

       This man page is correct for version 3.0 of the Samba suite.



SEE ALSO

       nsswitch.conf(5),   samba(7),   wbinfo(1),  ntlm_auth(8),  smb.conf(5),
       pam_winbind(8)



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.


       wbinfo and winbindd were written by Tim Potter.


       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.




                                                                   WINBINDD(8)

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