TimPotter Samba Team

tpot@linuxcare.com.au

&author.tridge; NaagMummaneni

getnag@rediffmail.com

Notes for Solaris JohnTrostel SNAP

jtrostel@snapserver.com

&author.jelmer; &author.jht; 27 June 2002 Integration of UNIX and Microsoft Windows NT through a unified logon has been considered a holy grail in heterogeneous computing environments for a long time. There is one other facility without which UNIX and Microsoft Windows network interoperability would suffer greatly. It is imperative that there be a mechanism for sharing files across UNIX systems and to be able to assign domain user and group ownerships with integrity. winbind is a component of the Samba suite of programs that solves the unified logon problem. Winbind uses a UNIX implementation of Microsoft RPC calls, Pluggable Authentication Modules, and the Name Service Switch to allow Windows NT domain users to appear and operate as UNIX users on a UNIX machine. This chapter describes the Winbind system, explaining the functionality it provides, how it is configured, and how it works internally. Winbind provides three separate functions: Authentication of user credentials (via PAM). Identity resolution (via NSS). Winbind maintains a database called winbind_idmap.tdb in which it stores mappings between UNIX UIDs / GIDs and NT SIDs. This mapping is used only for users and groups that do not have a local UID/GID. It stored the UID/GID allocated from the idmap uid/gid range that it has mapped to the NT SID. If idmap backend has been specified as ldapsam:url then instead of using a local mapping Winbind will obtain this information from the LDAP database. If winbindd is not running, smbd (which calls winbindd) will fall back to using purely local information from /etc/passwd and /etc/group and no dynamic mapping will be used. It is well known that UNIX and Microsoft Windows NT have different models for representing user and group information and use different technologies for implementing them. This fact has made it difficult to integrate the two systems in a satisfactory manner. One common solution in use today has been to create identically named user accounts on both the UNIX and Windows systems and use the Samba suite of programs to provide file and print services between the two. This solution is far from perfect, however, as adding and deleting users on both sets of machines becomes a chore and two sets of passwords are required &smbmdash; both of which can lead to synchronization problems between the UNIX and Windows systems and confusion for users. We divide the unified logon problem for UNIX machines into three smaller problems: Obtaining Windows NT user and group information. Authenticating Windows NT users. Password changing for Windows NT users. Ideally, a prospective solution to the unified logon problem would satisfy all the above components without duplication of information on the UNIX machines and without creating additional tasks for the system administrator when maintaining users and groups on either system. The Winbind system provides a simple and elegant solution to all three components of the unified logon problem. Winbind unifies UNIX and Windows NT account management by allowing a UNIX box to become a full member of an NT domain. Once this is done the UNIX box will see NT users and groups as if they were native UNIX users and groups, allowing the NT domain to be used in much the same manner that NIS+ is used within UNIX-only environments. The end result is that whenever any program on the UNIX machine asks the operating system to lookup a user or group name, the query will be resolved by asking the NT Domain Controller for the specified domain to do the lookup. Because Winbind hooks into the operating system at a low level (via the NSS name resolution modules in the C library), this redirection to the NT Domain Controller is completely transparent. Users on the UNIX machine can then use NT user and group names as they would native UNIX names. They can chown files so they are owned by NT domain users or even login to the UNIX machine and run a UNIX X-Window session as a domain user. The only obvious indication that Winbind is being used is that user and group names take the form DOMAIN\user and DOMAIN\group. This is necessary as it allows Winbind to determine that redirection to a Domain Controller is wanted for a particular lookup and which trusted domain is being referenced. Additionally, Winbind provides an authentication service that hooks into the Pluggable Authentication Modules (PAM) system to provide authentication via an NT domain to any PAM-enabled applications. This capability solves the problem of synchronizing passwords between systems since all passwords are stored in a single location (on the Domain Controller). Winbind is targeted at organizations that have an existing NT-based domain infrastructure into which they wish to put UNIX workstations or servers. Winbind will allow these organizations to deploy UNIX workstations without having to maintain a separate account infrastructure. This greatly simplifies the administrative overhead of deploying UNIX workstations into an NT-based organization. Another interesting way in which we expect Winbind to be used is as a central part of UNIX-based appliances. Appliances that provide file and print services to Microsoft-based networks will be able to use Winbind to provide seamless integration of the appliance into the domain. The Winbind system is designed around a client/server architecture. A long running winbindd daemon listens on a UNIX domain socket waiting for requests to arrive. These requests are generated by the NSS and PAM clients and is processed sequentially. The technologies used to implement Winbind are described in detail below. Over the last few years, efforts have been underway by various Samba Team members to decode various aspects of the Microsoft Remote Procedure Call (MSRPC) system. This system is used for most network-related operations between Windows NT machines including remote management, user authentication and print spooling. Although initially this work was done to aid the implementation of Primary Domain Controller (PDC) functionality in Samba, it has also yielded a body of code that can be used for other purposes. Winbind uses various MSRPC calls to enumerate domain users and groups and to obtain detailed information about individual users or groups. Other MSRPC calls can be used to authenticate NT domain users and to change user passwords. By directly querying a Windows PDC for user and group information, Winbind maps the NT account information onto UNIX user and group names. Since late 2001, Samba has gained the ability to interact with Microsoft Windows 2000 using its Native Mode protocols, rather than the NT4 RPC services. Using LDAP and Kerberos, a Domain Member running Winbind can enumerate users and groups in exactly the same way as a Windows 200x client would, and in so doing provide a much more efficient and effective Winbind implementation. The Name Service Switch, or NSS, is a feature that is present in many UNIX operating systems. It allows system information such as hostnames, mail aliases and user information to be resolved from different sources. For example, a standalone UNIX workstation may resolve system information from a series of flat files stored on the local filesystem. A networked workstation may first attempt to resolve system information from local files, and then consult an NIS database for user information or a DNS server for hostname information. The NSS application programming interface allows Winbind to present itself as a source of system information when resolving UNIX usernames and groups. Winbind uses this interface, and information obtained from a Windows NT server using MSRPC calls to provide a new source of account enumeration. Using standard UNIX library calls, one can enumerate the users and groups on a UNIX machine running Winbind and see all users and groups in a NT domain plus any trusted domain as though they were local users and groups. The primary control file for NSS is /etc/nsswitch.conf. When a UNIX application makes a request to do a lookup, the C library looks in /etc/nsswitch.conf for a line that matches the service type being requested, for example the passwd service type is used when user or group names are looked up. This config line specifies which implementations of that service should be tried and in what order. If the passwd config line is: passwd: files example then the C library will first load a module called /lib/libnss_files.so followed by the module /lib/libnss_example.so. The C library will dynamically load each of these modules in turn and call resolver functions within the modules to try to resolve the request. Once the request is resolved, the C library returns the result to the application. This NSS interface provides an easy way for Winbind to hook into the operating system. All that needs to be done is to put libnss_winbind.so in /lib/ then add winbind into /etc/nsswitch.conf at the appropriate place. The C library will then call Winbind to resolve user and group names. Pluggable Authentication Modules, also known as PAM, is a system for abstracting authentication and authorization technologies. With a PAM module it is possible to specify different authentication methods for different system applications without having to recompile these applications. PAM is also useful for implementing a particular policy for authorization. For example, a system administrator may only allow console logins from users stored in the local password file but only allow users resolved from a NIS database to log in over the network. Winbind uses the authentication management and password management PAM interface to integrate Windows NT users into a UNIX system. This allows Windows NT users to log in to a UNIX machine and be authenticated against a suitable Primary Domain Controller. These users can also change their passwords and have this change take effect directly on the Primary Domain Controller. PAM is configured by providing control files in the directory /etc/pam.d/ for each of the services that require authentication. When an authentication request is made by an application, the PAM code in the C library looks up this control file to determine what modules to load to do the authentication check and in what order. This interface makes adding a new authentication service for Winbind very easy. All that needs to be done is that the pam_winbind.so module is copied to /lib/security/ and the PAM control files for relevant services are updated to allow authentication via Winbind. See the PAM documentation in for more information. When a user or group is created under Windows NT/200x it is allocated a numerical relative identifier (RID). This is slightly different from UNIX which has a range of numbers that are used to identify users, and the same range in which to identify groups. It is Winbind's job to convert RIDs to UNIX ID numbers and vice versa. When Winbind is configured, it is given part of the UNIX user ID space and a part of the UNIX group ID space in which to store Windows NT users and groups. If a Windows NT user is resolved for the first time, it is allocated the next UNIX ID from the range. The same process applies for Windows NT groups. Over time, Winbind will have mapped all Windows NT users and groups to UNIX user IDs and group IDs. The results of this mapping are stored persistently in an ID mapping database held in a tdb database). This ensures that RIDs are mapped to UNIX IDs in a consistent way. SAM An active system can generate a lot of user and group name lookups. To reduce the network cost of these lookups, Winbind uses a caching scheme based on the SAM sequence number supplied by NT Domain Controllers. User or group information returned by a PDC is cached by Winbind along with a sequence number also returned by the PDC. This sequence number is incremented by Windows NT whenever any user or group information is modified. If a cached entry has expired, the sequence number is requested from the PDC and compared against the sequence number of the cached entry. If the sequence numbers do not match, then the cached information is discarded and up-to-date information is requested directly from the PDC. This section describes the procedures used to get Winbind up and running. Winbind is capable of providing access and authentication control for Windows Domain users through an NT or Windows 200x PDC for regular services, such as telnet and ftp, as well for Samba services. Why should I do this? This allows the Samba administrator to rely on the authentication mechanisms on the Windows NT/200x PDC for the authentication of Domain Members. Windows NT/200x users no longer need to have separate accounts on the Samba server. Who should be reading this document? This document is designed for system administrators. If you are implementing Samba on a file server and wish to (fairly easily) integrate existing Windows NT/200x users from your PDC onto the Samba server, this document is for you. If you have a Samba configuration file that you are currently using, BACK IT UP! If your system already uses PAM, back up the /etc/pam.d directory contents! If you haven't already made a boot disk, MAKE ONE NOW! Messing with the PAM configuration files can make it nearly impossible to log in to your machine. That's why you want to be able to boot back into your machine in single user mode and restore your /etc/pam.d back to the original state they were in if you get frustrated with the way things are going. The latest version of Samba-3 includes a functioning winbindd daemon. Please refer to the main Samba Web page or, better yet, your closest Samba mirror site for instructions on downloading the source code. To allow domain users the ability to access Samba shares and files, as well as potentially other services provided by your Samba machine, PAM must be set up properly on your machine. In order to compile the Winbind modules, you should have at least the PAM development libraries installed on your system. Please refer the PAM web site . Before starting, it is probably best to kill off all the Samba-related daemons running on your server. Kill off all &smbd;, &nmbd;, and &winbindd; processes that may be running. To use PAM, make sure that you have the standard PAM package that supplies the /etc/pam.d directory structure, including the PAM modules that are used by PAM-aware services, several pam libraries, and the /usr/doc and /usr/man entries for pam. Winbind built better in Samba if the pam-devel package is also installed. This package includes the header files needed to compile PAM-aware applications. PAM is a standard component of most current generation UNIX/Linux systems. Unfortunately, few systems install the pam-devel libraries that are needed to build PAM-enabled Samba. Additionally, Samba-3 may auto-install the Winbind files into their correct locations on your system, so before you get too far down the track be sure to check if the following configuration is really necessary. You may only need to configure /etc/nsswitch.conf. The libraries needed to run the &winbindd; daemon through nsswitch need to be copied to their proper locations: &rootprompt;cp ../samba/source/nsswitch/libnss_winbind.so /lib I also found it necessary to make the following symbolic link: &rootprompt; ln -s /lib/libnss_winbind.so /lib/libnss_winbind.so.2 And, in the case of Sun Solaris: &rootprompt;ln -s /usr/lib/libnss_winbind.so /usr/lib/libnss_winbind.so.1 &rootprompt;ln -s /usr/lib/libnss_winbind.so /usr/lib/nss_winbind.so.1 &rootprompt;ln -s /usr/lib/libnss_winbind.so /usr/lib/nss_winbind.so.2 Now, as root you need to edit /etc/nsswitch.conf to allow user and group entries to be visible from the &winbindd; daemon. My /etc/nsswitch.conf file look like this after editing: passwd: files winbind shadow: files group: files winbind The libraries needed by the winbindd daemon will be automatically entered into the ldconfig cache the next time your system reboots, but it is faster (and you do not need to reboot) if you do it manually: &rootprompt;/sbin/ldconfig -v | grep winbind This makes libnss_winbind available to winbindd and echos back a check to you. (This section is only for those running AIX.) The Winbind AIX identification module gets built as libnss_winbind.so in the nsswitch directory of the Samba source. This file can be copied to /usr/lib/security, and the AIX naming convention would indicate that it should be named WINBIND. A stanza like the following: WINBIND: program = /usr/lib/security/WINBIND options = authonly can then be added to /usr/lib/security/methods.cfg. This module only supports identification, but there have been success reports using the standard Winbind PAM module for authentication. Use caution configuring loadable authentication modules since you can make it impossible to logon to the system. More information about the AIX authentication module API can be found at Kernel Extensions and Device Support Programming Concepts for AIX in Chapter 18(John, there is no section like this in 18). Loadable Authentication Module Programming Interface and more information on administering the modules can be found at System Management Guide: Operating System and Devices. Several parameters are needed in the &smb.conf; file to control the behavior of &winbindd;. These are described in more detail in the winbindd 8 man page. My &smb.conf; file, as shown in , was modified to include the necessary entries in the [global] section. [global] <...> separate domain and username with '+', like DOMAIN+username winbind separator+ use uids from 10000 to 20000 for domain users idmap uid10000-20000 use gids from 10000 to 20000 for domain groups winbind gid10000-20000 allow enumeration of winbind users and groups winbind enum usersyes winbind enum groupsyes give winbind users a real shell (only needed if they have telnet access) template homedir/home/winnt/%D/%U template shell/bin/bash Enter the following command to make the Samba server join the PDC domain, where DOMAIN is the name of your Windows domain and Administrator is a domain user who has administrative privileges in the domain. &rootprompt;/usr/local/samba/bin/net rpc join -S PDC -U Administrator The proper response to the command should be: Joined the domain DOMAIN where DOMAIN is your DOMAIN name. Eventually, you will want to modify your Samba startup script to automatically invoke the winbindd daemon when the other parts of Samba start, but it is possible to test out just the Winbind portion first. To start up Winbind services, enter the following command as root: &rootprompt;/usr/local/samba/bin/winbindd The above assumes that Samba has been installed in the /usr/local/samba directory tree. You may need to search for the location of Samba files if this is not the location of winbindd on your system. Winbindd can now also run in dual daemon modei. This will make it run as two processes. The first will answer all requests from the cache, thus making responses to clients faster. The other will update the cache for the query that the first has just responded. The advantage of this is that responses stay accurate and are faster. You can enable dual daemon mode by adding -B to the commandline: &rootprompt;/usr/local/samba/bin/winbindd -B I'm always paranoid and like to make sure the daemon is really running. &rootprompt;ps -ae | grep winbindd This command should produce output like this, if the daemon is running you would expect to see a report something like this: 3025 ? 00:00:00 winbindd Now, for the real test, try to get some information about the users on your PDC: &rootprompt;/usr/local/samba/bin/wbinfo -u This should echo back a list of users on your Windows users on your PDC. For example, I get the following response: CEO+Administrator CEO+burdell CEO+Guest CEO+jt-ad CEO+krbtgt CEO+TsInternetUser Obviously, I have named my domain CEO and my winbind separator is +. You can do the same sort of thing to get group information from the PDC: &rootprompt;/usr/local/samba/bin/wbinfo -g CEO+Domain Admins CEO+Domain Users CEO+Domain Guests CEO+Domain Computers CEO+Domain Controllers CEO+Cert Publishers CEO+Schema Admins CEO+Enterprise Admins CEO+Group Policy Creator Owners The function getent can now be used to get unified lists of both local and PDC users and groups. Try the following command: &rootprompt;getent passwd You should get a list that looks like your /etc/passwd list followed by the domain users with their new UIDs, GIDs, home directories and default shells. The same thing can be done for groups with the command: &rootprompt;getent group The &winbindd; daemon needs to start up after the &smbd; and &nmbd; daemons are running. To accomplish this task, you need to modify the startup scripts of your system. They are located at /etc/init.d/smb in Red Hat Linux and they are located in /etc/init.d/samba in Debian Linux. Edit your script to add commands to invoke this daemon in the proper sequence. My startup script starts up &smbd;, &nmbd;, and &winbindd; from the /usr/local/samba/bin directory directly. The start function in the script looks like this: start() { KIND="SMB" echo -n $"Starting $KIND services: " daemon /usr/local/samba/bin/smbd $SMBDOPTIONS RETVAL=$? echo KIND="NMB" echo -n $"Starting $KIND services: " daemon /usr/local/samba/bin/nmbd $NMBDOPTIONS RETVAL2=$? echo KIND="Winbind" echo -n $"Starting $KIND services: " daemon /usr/local/samba/bin/winbindd RETVAL3=$? echo [ $RETVAL -eq 0 -a $RETVAL2 -eq 0 -a $RETVAL3 -eq 0 ] && \ touch /var/lock/subsys/smb || RETVAL=1 return $RETVAL } If you would like to run winbindd in dual daemon mode, replace the line : daemon /usr/local/samba/bin/winbindd in the example above with: daemon /usr/local/samba/bin/winbindd -B . The stop function has a corresponding entry to shut down the services and looks like this: stop() { KIND="SMB" echo -n $"Shutting down $KIND services: " killproc smbd RETVAL=$? echo KIND="NMB" echo -n $"Shutting down $KIND services: " killproc nmbd RETVAL2=$? echo KIND="Winbind" echo -n $"Shutting down $KIND services: " killproc winbindd RETVAL3=$? [ $RETVAL -eq 0 -a $RETVAL2 -eq 0 -a $RETVAL3 -eq 0 ] && \ rm -f /var/lock/subsys/smb echo "" return $RETVAL } Winbind does not work on Solaris 9, see for details. On Solaris, you need to modify the /etc/init.d/samba.server startup script. It usually only starts smbd and nmbd but should now start winbindd, too. If you have Samba installed in /usr/local/samba/bin, the file could contains something like this: ## ## samba.server ## if [ ! -d /usr/bin ] then # /usr not mounted exit fi killproc() { # kill the named process(es) pid=`/usr/bin/ps -e | /usr/bin/grep -w $1 | /usr/bin/sed -e 's/^ *//' -e 's/ .*//'` [ "$pid" != "" ] && kill $pid } # Start/stop processes required for Samba server case "$1" in 'start') # # Edit these lines to suit your installation (paths, workgroup, host) # echo Starting SMBD /usr/local/samba/bin/smbd -D -s \ /usr/local/samba/smb.conf echo Starting NMBD /usr/local/samba/bin/nmbd -D -l \ /usr/local/samba/var/log -s /usr/local/samba/smb.conf echo Starting Winbind Daemon /usr/local/samba/bin/winbindd ;; 'stop') killproc nmbd killproc smbd killproc winbindd ;; *) echo "Usage: /etc/init.d/samba.server { start | stop }" ;; esac Again, if you would like to run Samba in dual daemon mode, replace: /usr/local/samba/bin/winbindd in the script above with: /usr/local/samba/bin/winbindd -B If you restart the &smbd;, &nmbd;, and &winbindd; daemons at this point, you should be able to connect to the Samba server as a Domain Member just as if you were a local user. If you have made it this far, you know that winbindd and Samba are working together. If you want to use Winbind to provide authentication for other services, keep reading. The PAM configuration files need to be altered in this step. (Did you remember to make backups of your original /etc/pam.d files? If not, do it now.) You will need a PAM module to use winbindd with these other services. This module will be compiled in the ../source/nsswitch directory by invoking the command: &rootprompt;make nsswitch/pam_winbind.so from the ../source directory. The pam_winbind.so file should be copied to the location of your other PAM security modules. On my RedHat system, this was the /lib/security directory. On Solaris, the PAM security modules reside in /usr/lib/security. &rootprompt;cp ../samba/source/nsswitch/pam_winbind.so /lib/security The /etc/pam.d/samba file does not need to be changed. I just left this file as it was: auth required /lib/security/pam_stack.so service=system-auth account required /lib/security/pam_stack.so service=system-auth The other services that I modified to allow the use of Winbind as an authentication service were the normal login on the console (or a terminal session), telnet logins, and ftp service. In order to enable these services, you may first need to change the entries in /etc/xinetd.d (or /etc/inetd.conf). Red Hat Linux 7.1 and later uses the new xinetd.d structure, in this case you need to change the lines in /etc/xinetd.d/telnet and /etc/xinetd.d/wu-ftp from enable = no to: enable = yes For ftp services to work properly, you will also need to either have individual directories for the domain users already present on the server, or change the home directory template to a general directory for all domain users. These can be easily set using the &smb.conf; global entry template homedir. The /etc/pam.d/ftp file can be changed to allow Winbind ftp access in a manner similar to the samba file. My /etc/pam.d/ftp file was changed to look like this: auth required /lib/security/pam_listfile.so item=user sense=deny \ file=/etc/ftpusers onerr=succeed auth sufficient /lib/security/pam_winbind.so auth required /lib/security/pam_stack.so service=system-auth auth required /lib/security/pam_shells.so account sufficient /lib/security/pam_winbind.so account required /lib/security/pam_stack.so service=system-auth session required /lib/security/pam_stack.so service=system-auth The /etc/pam.d/login file can be changed nearly the same way. It now looks like this: auth required /lib/security/pam_securetty.so auth sufficient /lib/security/pam_winbind.so auth sufficient /lib/security/pam_UNIX.so use_first_pass auth required /lib/security/pam_stack.so service=system-auth auth required /lib/security/pam_nologin.so account sufficient /lib/security/pam_winbind.so account required /lib/security/pam_stack.so service=system-auth password required /lib/security/pam_stack.so service=system-auth session required /lib/security/pam_stack.so service=system-auth session optional /lib/security/pam_console.so In this case, I added the auth sufficient /lib/security/pam_winbind.so lines as before, but also added the required pam_securetty.so above it, to disallow root logins over the network. I also added a sufficient /lib/security/pam_unix.so use_first_pass line after the winbind.so line to get rid of annoying double prompts for passwords. The /etc/pam.conf needs to be changed. I changed this file so my Domain users can logon both locally as well as telnet. The following are the changes that I made. You can customize the pam.conf file as per your requirements, but be sure of those changes because in the worst case it will leave your system nearly impossible to boot. # #ident "@(#)pam.conf 1.14 99/09/16 SMI" # # Copyright (c) 1996-1999, Sun Microsystems, Inc. # All Rights Reserved. # # PAM configuration # # Authentication management # login auth required /usr/lib/security/pam_winbind.so login auth required /usr/lib/security/$ISA/pam_UNIX.so.1 try_first_pass login auth required /usr/lib/security/$ISA/pam_dial_auth.so.1 try_first_pass # rlogin auth sufficient /usr/lib/security/pam_winbind.so rlogin auth sufficient /usr/lib/security/$ISA/pam_rhosts_auth.so.1 rlogin auth required /usr/lib/security/$ISA/pam_UNIX.so.1 try_first_pass # dtlogin auth sufficient /usr/lib/security/pam_winbind.so dtlogin auth required /usr/lib/security/$ISA/pam_UNIX.so.1 try_first_pass # rsh auth required /usr/lib/security/$ISA/pam_rhosts_auth.so.1 other auth sufficient /usr/lib/security/pam_winbind.so other auth required /usr/lib/security/$ISA/pam_UNIX.so.1 try_first_pass # # Account management # login account sufficient /usr/lib/security/pam_winbind.so login account requisite /usr/lib/security/$ISA/pam_roles.so.1 login account required /usr/lib/security/$ISA/pam_UNIX.so.1 # dtlogin account sufficient /usr/lib/security/pam_winbind.so dtlogin account requisite /usr/lib/security/$ISA/pam_roles.so.1 dtlogin account required /usr/lib/security/$ISA/pam_UNIX.so.1 # other account sufficient /usr/lib/security/pam_winbind.so other account requisite /usr/lib/security/$ISA/pam_roles.so.1 other account required /usr/lib/security/$ISA/pam_UNIX.so.1 # # Session management # other session required /usr/lib/security/$ISA/pam_UNIX.so.1 # # Password management # #other password sufficient /usr/lib/security/pam_winbind.so other password required /usr/lib/security/$ISA/pam_UNIX.so.1 dtsession auth required /usr/lib/security/$ISA/pam_UNIX.so.1 # # Support for Kerberos V5 authentication (uncomment to use Kerberos) # #rlogin auth optional /usr/lib/security/$ISA/pam_krb5.so.1 try_first_pass #login auth optional /usr/lib/security/$ISA/pam_krb5.so.1 try_first_pass #dtlogin auth optional /usr/lib/security/$ISA/pam_krb5.so.1 try_first_pass #other auth optional /usr/lib/security/$ISA/pam_krb5.so.1 try_first_pass #dtlogin account optional /usr/lib/security/$ISA/pam_krb5.so.1 #other account optional /usr/lib/security/$ISA/pam_krb5.so.1 #other session optional /usr/lib/security/$ISA/pam_krb5.so.1 #other password optional /usr/lib/security/$ISA/pam_krb5.so.1 try_first_pass I also added a try_first_pass line after the winbind.so line to get rid of annoying double prompts for passwords. Now restart your Samba and try connecting through your application that you configured in the pam.conf. The Winbind system, through the use of the Name Service Switch, Pluggable Authentication Modules, and appropriate Microsoft RPC calls have allowed us to provide seamless integration of Microsoft Windows NT domain users on a UNIX system. The result is a great reduction in the administrative cost of running a mixed UNIX and NT network. Winbind has a number of limitations in its current released version that we hope to overcome in future releases: Winbind is currently only available for the Linux, Solaris, AIX, and IRIX operating systems, although ports to other operating systems are certainly possible. For such ports to be feasible, we require the C library of the target operating system to support the Name Service Switch and Pluggable Authentication Modules systems. This is becoming more common as NSS and PAM gain support among UNIX vendors. The mappings of Windows NT RIDs to UNIX IDs is not made algorithmically and depends on the order in which unmapped users or groups are seen by Winbind. It may be difficult to recover the mappings of RID to UNIX ID mapping if the file containing this information is corrupted or destroyed. Currently the Winbind PAM module does not take into account possible workstation and logon time restrictions that may be set for Windows NT users, this is instead up to the PDC to enforce. Do not under any circumstances run nscd on any system on which winbindd is running. If nscd is running on the UNIX/Linux system, then even though NSSWITCH is correctly configured it will not be possible to resolve domain users and groups for file and directory controls. My &smb.conf; file is correctly configured. I have specified idmap uid12000, and idmap gid3000-3500 and winbind is running. When I do the following it all works fine. &rootprompt;wbinfo -u MIDEARTH+maryo MIDEARTH+jackb MIDEARTH+ameds ... MIDEARTH+root &rootprompt;wbinfo -g MIDEARTH+Domain Users MIDEARTH+Domain Admins MIDEARTH+Domain Guests ... MIDEARTH+Accounts &rootprompt;getent passwd root:x:0:0:root:/root:/bin/bash bin:x:1:1:bin:/bin:/bin/bash ... maryo:x:15000:15003:Mary Orville:/home/MIDEARTH/maryo:/bin/false But the following command just fails: &rootprompt;chown maryo a_file chown: `maryo': invalid user This is driving me nuts! What can be wrong? Same problem as the one above. Your system is likely running nscd, the name service caching daemon. Shut it down, do not restart it! You will find your problem resolved.