smbpasswd Man page

SMBPASSWD(8) System Administration tools SMBPASSWD(8)

NAME

smbpasswd – change a user’s SMB password

SYNOPSIS

smbpasswd [-a] [-c ] [-x] [-d] [-e] [-D debuglevel] [-n] [-r ] [-R ] [-m] [-U username[%password]] [-h] [-s] [-w pass] [-W] [-i] [-L] [username]

DESCRIPTION

This tool is part of the samba(7) 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 user’s SMB password on the local machine. This is similar to
the way the passwd 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(8).
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 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
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
default passdb backends require the user to 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.

-c
This option can be used to specify the path and file name of the
smb.conf configuration file when it is important to use other than
the default file and / or location.

-x
This option specifies that the username following should be deleted
from the local smbpasswd file.

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 user’s password entry to write this
information and the command will FAIL. 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
FAIL to enable the account. 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 = yes

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 smbpasswd 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:

· lmhosts: Lookup an IP address in the Samba lmhosts file. If the
line in lmhosts has no name type attached to the NetBIOS name
(see the lmhosts(5) for details) then any name type matches for
lookup.

· host: Do a standard host name to IP address resolution, using
the system /etc/hosts, NIS, or DNS lookups. This method of name
resolution is operating system depended for instance on IRIX or
Solaris this may be controlled by the /etc/nsswitch.conf file).
Note that this method is only used if the NetBIOS name type
being queried is the 0x20 (server) name type, otherwise it is
ignored.

· wins: Query a name with the IP address listed in the wins
server parameter. If no WINS server has been specified this
method will be ignored.

· bcast: Do a broadcast on each of the known local interfaces
listed in the interfaces parameter. This is the least reliable
of the name resolution methods as it depends on the target host
being on a locally connected subnet.

The default order is lmhosts, host, wins, bcast and without this
parameter or any entry in the smb.conf(5) 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.

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 its old and new passwords from standard input, rather
than from /dev/tty (like the passwd program does). This option
is to aid people writing scripts to drive smbpasswd

-w password
This parameter is only available if Samba has been compiled with
LDAP support. The -w switch is used to specify the password to be
used with the ldap admin dn. Note that the password is stored in
the secrets.tdb and is keyed off of the admin’s DN. This means that
if the value of ldap admin dn ever changes, the password will need
to be manually updated as well.

-W
NOTE: This option is same as “-w” except that the password should
be entered using stdin.

This parameter is only available if Samba has been compiled with
LDAP support. The -W switch is used to specify the password to be
used with the ldap admin dn. Note that the password is stored in
the secrets.tdb and is keyed off of the admin’s DN. This means that
if the value of ldap admin dn ever changes, the password will need
to be manually updated as well.

-i
This option tells smbpasswd that the account being changed is an
interdomain trust account. Currently this is used when Samba is
being used as an NT Primary Domain Controller. The account contains
the info about another trusted domain.

This option is only available when running smbpasswd as root.

-L
Run in local mode.

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 either allow
hosts or deny hosts entry in the smb.conf(5) 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.

VERSION
This man page is correct for version 3 of the Samba suite.

SEE ALSO

smbpasswd(5), Samba(7).

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.

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 Samba 2.0 release by Jeremy Allison. 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.

Samba 4.3 09/23/2016 SMBPASSWD(8)