smbpasswd (8)

Samba

23 Oct 1998

NAME

smbpasswd - change a users SMB password

SYNOPSIS

smbpasswd [-a] [-d] [-e] [-D debug level] [-n] [-r remote_machine] [-R name resolve order] [-m] [-j DOMAIN] [-U username] [-h] [-s] username

DESCRIPTION

This program is part of the Samba suite.

The smbpasswd program has several different functions, depending on whether it is run by the root user or not. When run as a normal user it allows the user to change the password used for their SMB sessions on any machines that store SMB passwords.

By default (when run with no arguments) it will attempt to change the current users SMB password on the local machine. This is similar to the way the passwd (1) program works. smbpasswd differs from how the passwd program works however in that it is not setuid root but works in a client-server mode and communicates with a locally running smbd. As a consequence in order for this to succeed the smbd daemon must be running on the local machine. On a UNIX machine the encrypted SMB passwords are usually stored in the smbpasswd (5) file.

When run by an ordinary user with no options. smbpasswd will prompt them for their old smb password and then ask them for their new password twice, to ensure that the new password was typed correctly. No passwords will be echoed on the screen whilst being typed. If you have a blank smb password (specified by the string "NO PASSWORD" in the smbpasswd file) then just press the <Enter> key when asked for your old password.

smbpasswd can also be used by a normal user to change their SMB password on remote machines, such as Windows NT Primary Domain Controllers. See the (-r) and -U options below.

When run by root, smbpasswd allows new users to be added and deleted in the smbpasswd file, as well as allows changes to the attributes of the user in this file to be made. When run by root, smbpasswd accesses the local smbpasswd file directly, thus enabling changes to be made even if smbd is not running.

OPTIONS

-a
This option specifies that the username following should be added to the local smbpasswd file, with the new password typed (type <Enter> for the old password). This option is ignored if the username following already exists in the smbpasswd file and it is treated like a regular change password command. Note that the user to be added must already exist in the system password file (usually /etc/passwd) else the request to add the user will fail.

This option is only available when running smbpasswd as root.

-d
This option specifies that the username following should be disabled in the local smbpasswd file. This is done by writing a 'D' flag into the account control space in the smbpasswd file. Once this is done all attempts to authenticate via SMB using this username will fail.

If the smbpasswd file is in the 'old' format (pre-Samba 2.0 format) there is no space in the users password entry to write this information and so the user is disabled by writing 'X' characters into the password space in the smbpasswd file. See smbpasswd (5) for details on the 'old' and new password file formats.

This option is only available when running smbpasswd as root.

-e
This option specifies that the username following should be enabled in the local smbpasswd file, if the account was previously disabled. If the account was not disabled this option has no effect. Once the account is enabled then the user will be able to authenticate via SMB once again.

If the smbpasswd file is in the 'old' format then smbpasswd will prompt for a new password for this user, otherwise the account will be enabled by removing the 'D' flag from account control space in the smbpasswd file. See smbpasswd (5) for details on the 'old' and new password file formats.

This option is only available when running smbpasswd as root.

-D 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 smbpasswd. At level 0, only critical errors and serious warnings will be logged.

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.

-n
This option specifies that the username following should have their password set to null (i.e. a blank password) in the local smbpasswd file. This is done by writing the string "NO PASSWORD" as the first part of the first password stored in the smbpasswd file.

Note that to allow users to logon to a Samba server once the password has been set to "NO PASSWORD" in the smbpasswd file the administrator must set the following parameter in the [global] section of the smb.conf file :

null passwords = true

This option is only available when running smbpasswd as root.

-r remote machine name
This option allows a user to specify what machine they wish to change their password on. Without this parameter smbpasswd defaults to the local host. The "remote machine name" is the NetBIOS name of the SMB/CIFS server to contact to attempt the password change. This name is resolved into an IP address using the standard name resolution mechanism in all programs of the Samba suite. See the -R name resolve order parameter for details on changing this resolving mechanism.

The username whose password is changed is that of the current UNIX logged on user. See the -U username parameter for details on changing the password for a different username.

Note that if changing a Windows NT Domain password the remote machine specified must be the Primary Domain Controller for the domain (Backup Domain Controllers only have a read-only copy of the user account database and will not allow the password change).

Note that Windows 95/98 do not have a real password database so it is not possible to change passwords specifying a Win95/98 machine as remote machine target.

-R name resolve order
This option allows the user of smbclient to determine what name resolution services to use when looking up the NetBIOS name of the host being connected to.

The options are :"lmhosts", "host", "wins" and "bcast". They cause names to be resolved as follows :

If this parameter is not set then the name resolve order defined in the smb.conf file parameter name resolve order will be used.

The default order is lmhosts, host, wins, bcast and without this parameter or any entry in the smb.conf file the name resolution methods will be attempted in this order.

-m
This option tells smbpasswd that the account being changed is a MACHINE account. Currently this is used when Samba is being used as an NT Primary Domain Controller. PDC support is not a supported feature in Samba2.0 but will become supported in a later release. If you wish to know more about using Samba as an NT PDC then please subscribe to the mailing list samba-ntdom@samba.org.

This option is only available when running smbpasswd as root.

-j DOMAIN
This option is used to add a Samba server into a Windows NT Domain, as a Domain member capable of authenticating user accounts to any Domain Controller in the same way as a Windows NT Server. See the security=domain option in the smb.conf (5) man page.

In order to be used in this way, the Administrator for the Windows NT Domain must have used the program "Server Manager for Domains" to add the primary NetBIOS name of the Samba server as a member of the Domain.

After this has been done, to join the Domain invoke smbpasswd with this parameter. smbpasswd will then look up the Primary Domain Controller for the Domain (found in the smb.conf file in the parameter password server and change the machine account password used to create the secure Domain communication. This password is then stored by smbpasswd in a file, read only by root, called <Domain>.<Machine>.mac where <Domain> is the name of the Domain we are joining and <Machine> is the primary NetBIOS name of the machine we are running on.

Once this operation has been performed the smb.conf file may be updated to set the security=domain option and all future logins to the Samba server will be authenticated to the Windows NT PDC.

Note that even though the authentication is being done to the PDC all users accessing the Samba server must still have a valid UNIX account on that machine.

This option is only available when running smbpasswd as root.

-U username
This option may only be used in conjunction with the -r option. When changing a password on a remote machine it allows the user to specify the user name on that machine whose password will be changed. It is present to allow users who have different user names on different systems to change these passwords.

-h
This option prints the help string for smbpasswd, selecting the correct one for running as root or as an ordinary user.

-s
This option causes smbpasswd to be silent (i.e. not issue prompts) and to read it's old and new passwords from standard input, rather than from /dev/tty (like the passwd (1) program does). This option is to aid people writing scripts to drive smbpasswd

username
This specifies the username for all of the root only options to operate on. Only root can specify this parameter as only root has the permission needed to modify attributes directly in the local smbpasswd file.

NOTES

Since smbpasswd works in client-server mode communicating with a local smbd for a non-root user then the smbd daemon must be running for this to work. A common problem is to add a restriction to the hosts that may access the smbd running on the local machine by specifying a "allow hosts" or "deny hosts" entry in the smb.conf file and neglecting to allow "localhost" access to the smbd.

In addition, the smbpasswd command is only useful if Samba has been set up to use encrypted passwords. See the file ENCRYPTION.txt in the docs directory for details on how to do this.

VERSION

This man page is correct for version 2.0 of the Samba suite.

AUTHOR

The original Samba software and related utilities were created by Andrew Tridgell samba-bugs@samba.org. Samba is now developed by the Samba Team as an Open Source project similar to the way the Linux kernel is developed.

The original Samba man pages were written by Karl Auer. The man page sources were converted to YODL format (another excellent piece of Open Source software, available at ftp://ftp.icce.rug.nl/pub/unix/) and updated for the Samba2.0 release by Jeremy Allison. samba-bugs@samba.org.

See samba (7) to find out how to get a full list of contributors and details on how to submit bug reports, comments etc.