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 connections 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 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 supports the auth, account and password module-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 libnss_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 service:

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
## 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

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 mapping 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 command. 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 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.

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 parameters in the smb.conf(5) file. All parameters should be specified in the [global] section of smb.conf.

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 an early Red Hat 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_unix.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 net 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/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(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 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(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 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, 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 the winbindd daemon.

FILES

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 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. The conversion to DocBook XML 4.2 for Samba 3.0 was done by Alexander Bokovoy.