WINBINDD(8)WINBINDD(8)NAME
winbindd - Name Service Switch daemon for resolving names
from NT servers
SYNOPSIS
nmblookup [ -d debuglevel ] [ -i ] [ -S ] [ -r ] [ -A
] [ -h ] [ -B <broadcast address> ] [ -U <unicast
address> ] [ -d <debug level> ] [ -s <smb config file> ]
[ -i <NetBIOS scope> ] [ -T ] name
DESCRIPTION
This tool is part of the Sambasuite version 3.0 and
describes functionality not yet implemented in the main
version of Samba.
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 ser-
vices such as NIS or DNS. The exact behaviour can be con-
figured 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 authenti-
cation services via an associated PAM module.
The following nsswitch databases are implemented by the
winbindd service:
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
OPTIONS
09 July 2001 1
WINBINDD(8)WINBINDD(8)-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 con-
figuration parameters in the smb.conf(5) file. All parame-
ters 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 presented to users. By
default, winbindd will use the traditional '\' sep-
arator so that the unix user names look like
DOMAIN\username. In some cases this separator char-
acter 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 conflicts with the unix
directory separator) or a '+ 'character. The '+'
character appears to be the best choice for 100%
compatibility with existing unix utilities, but may
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WINBINDD(8)WINBINDD(8)
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 dae-
mon. This range of group ids should have no exist-
ing local or NIS groups within it as strange con-
flicts can occur otherwise.
Default: winbind gid = <empty string>
Example: winbind gid = 10000-20000
winbind cache time
This parameter specifies the number of seconds the
winbindd daemon will cache user and group informa-
tion 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 win-
bind cache time seconds. Otherwise the item is
fetched from the server. This means that as long as
the account database is not actively changing win-
bindd 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 sup-
press the enumeration of users through the setp-
went(), 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.
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WINBINDD(8)WINBINDD(8)
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 sup-
press the enumeration of groups through the set-
grent(), 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 authen-
tication 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:
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WINBINDD(8)WINBINDD(8)
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 the
samedit program like this:
samedit -S '*' -W DOMAIN -UAdministrator
The username after the -U can be any Domain user that has
administrator privileges on the machine. Next from within
samedit, run the command:
createuser MACHINE$ -j DOMAIN -L
This assumes your domain is called "DOMAIN" and your Samba
workstation is called "MACHINE".
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
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WINBINDD(8)WINBINDD(8)
domain user, using the DOMAIN+user syntax for the user-
name. 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 run-
ning 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 nss-
witch module read an environment variable named $WIN-
BINDD_DOMAIN. If this variable 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 map-
ping file is damaged or destroyed then the mappings will
be lost.
SIGNALS
The following signals can be used to manipulate the win-
bindd 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 infor-
mation. The list of other domains trusted by win-
bindd is also reloaded.
SIGUSR1
The SIGUSR1 signal will cause winbindd to write
status information to the winbind log file includ-
ing 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.
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WINBINDD(8)WINBINDD(8)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 direc-
tory 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-lock-
dir 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. winbindd is however not available in the stable
release of Samba as of yet.
SEE ALSOnsswitch.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
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