WINBINDD(8) WINBINDD(8)
NAME
winbindd - Name Service Switch daemon for resolving names from NT servers
SYNOPSIS
winbindd [ -i ] [ -d <debug level> ] [ -s <smb config file> ]
DESCRIPTION
This program is part of the Samba suite.
winbindd is a daemon that provides a service for the Name Service Switch capability that is present in most modern C libraries. The Name
Service Switch allows user and system information to be obtained 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
service can also provide authentication services via an associated PAM module.
The pam_winbind module in the 2.2.2 release only supports the auth and account module-types. The latter is simply performs a getpwnam() to
verify that the system can obtain a uid for the user. If the libnss_winbind library has been correctly installed, this should always
suceed.
The following nsswitch databases are implemented by the winbindd service:
hosts User information traditionally stored in the hosts(5) file and used by gethostbyname(3) functions. Names are resolved through the
WINS server or by broadcast.
passwd User information traditionally stored in the passwd(5) file and used by getpwent(3) functions.
group Group information traditionally stored in the group(5) file and used by getgrent(3) functions.
For example, the following simple configuration in the /etc/nsswitch.conf file can be used to initially resolve user and group information
from /etc/passwd and /etc/group and then from the Windows NT server.
passwd: files winbind
group: files 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.
OPTIONS
-d debuglevel
Sets the debuglevel to an integer between 0 and 100. 0 is for no debugging and 100 is for reams and reams. To submit a bug report to
the Samba Team, use debug level 100 (see BUGS.txt).
-i Tells winbindd to not become a daemon and detach from the current terminal. This option is used by developers when interactive
debugging of winbindd is required.
NAME AND ID RESOLUTION
Users and groups on a Windows NT server are assigned a relative id (rid) which is unique for the domain when the user or group is created.
To convert the Windows NT user or group into a unix user or group, a mapping between rids 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
command. The allocated unix ids are stored in a database file under the Samba lock directory and will be remembered.
WARNING: The rid to unix id database is the only location where the user 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.
CONFIGURATION
Configuration of the winbindd daemon is done through configuration parameters in the smb.conf(5) file. All parameters should be specified
in the [global] section of smb.conf.
winbind separator
The winbind separator option allows you to specify how NT domain names and user names are combined into unix user names when pre-
sented to users. By default, winbindd will use the traditional '' separator so that the unix user names look like DOMAINusername.
In some cases this separator character may cause problems as the '' character has special meaning in unix shells. In that case you
can use the winbind separator option to specify an alternative separator character. Good alternatives may be '/' (although that con-
flicts with the unix directory separator) or a '+ 'character. The '+' character appears to be the best choice for 100% compatibil-
ity with existing unix utilities, but may be an aesthetically bad choice depending on your taste.
Default: winbind separator =
Example: winbind separator = +
winbind uid
The winbind uid parameter specifies the range of user ids that are allocated by the winbindd daemon. This range of ids should have
no existing local or NIS users within it as strange conflicts can occur otherwise.
Default: winbind uid = <empty string> Example: winbind uid = 10000-20000
winbind gid
The winbind gid parameter specifies the range of group ids that are allocated by the winbindd daemon. This range of group ids
should have no existing local or NIS groups within it as strange conflicts can occur otherwise.
Default: winbind gid = <empty string> Example: winbind gid = 10000-20000 .TP winbind cache time This parameter specifies the number
of seconds the winbindd daemon will cache user and group information before querying a Windows NT server again. When a item in the
cache is older than this time winbindd will ask the domain controller for the sequence number of the server's account database. If
the sequence number has not changed then the cached item is marked as valid for a further winbind cache time seconds. Otherwise the
item is fetched from the server. This means that as long as the account database is not actively changing winbindd will only have to
send one sequence number query packet every winbind cache time seconds.
Default: winbind cache time = 15
winbind enum users
On large installations it may be necessary to suppress the enumeration of users through the setpwent(), getpwent() and endpwent()
group of system calls. If the winbind enum users parameter is false, calls to the getpwent system call will not return any data.
Warning: Turning off user enumeration may cause some programs to behave oddly. For example, the finger program relies on having
access to the full user list when searching for matching usernames.
Default: winbind enum users = yes
winbind enum groups
On large installations it may be necessary to suppress the enumeration of groups through the setgrent(), getgrent() and endgrent()
group of system calls. If the winbind enum groups parameter is false, calls to the getgrent() system call will not return any data.
Warning: Turning off group enumeration may cause some programs to behave oddly.
Default: winbind enum groups = no
template homedir
When filling out the user information for a Windows NT user, the winbindd daemon uses this parameter to fill in the home directory
for that user. If the string %D is present it is substituted with the user's Windows NT domain name. If the string %U is present it
is substituted with the user's Windows NT user name.
Default: template homedir = /home/%D/%U
template shell
When filling out the user information for a Windows NT user, the winbindd daemon uses this parameter to fill in the shell for that
user.
Default: template shell = /bin/false
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 .PP The next step is to join the domain. To do that use the smbpasswd program like this:
smbpasswd -j DOMAIN -r PDC -U Administrator
The username after the -U can be any Domain user that has administrator privileges on the machine. Substitute your domain name for
"DOMAIN" and the name of your PDC for "PDC".
Next copy libnss_winbind.so to /lib and pam_winbind.so to /lib/security. 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 containing directives like the following:
[global]
winbind separator = +
winbind cache time = 10
template shell = /bin/bash
template homedir = /home/%D/%U
winbind uid = 10000-20000
winbind 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 syntax 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 must be running on the local machine for winbindd to work. winbindd queries the list of trusted domains for the Windows NT server on
startup and when a SIGHUP is received. Thus, for a running winbindd to become aware of new trust relationships between servers, it must be
sent a SIGHUP signal.
Client processes resolving names through the winbindd nsswitch module read an environment variable named $WINBINDD_DOMAIN. If this vari-
able contains a comma separated list of Windows NT domain names, then winbindd will only resolve users and groups within those Windows NT
domains.
PAM is really easy to misconfigure. Make sure you know what you are doing 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
user and group ids will only be valid for the local machine.
If the the Windows NT RID 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 the winbindd 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.
SIGUSR1
The SIGUSR1 signal will cause winbindd to write status information to the winbind log file including information about the number
of user and group ids allocated by winbindd.
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 attempt
to connect to the winbindd daemon if both the /tmp/.winbindd directory and /tmp/.winbindd/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 2.2 of the Samba suite.
SEE ALSO
nsswitch.conf(5), samba(7) wbinfo(1) smb.conf(5)
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.
wbinfo and winbindd were written by Tim Potter.
The conversion to DocBook for Samba 2.2 was done by Gerald Carter
19 November 2002 WINBINDD(8)