SMBPASSWD(8) UNIX System V (01 February 2003) SMBPASSWD(8)
NAME [Toc] [Back]
smbpasswd - change a user's SMB password
SYNOPSIS [Toc] [Back]
When run by root:
smbpasswd [ options ] [ username ] [ password ]
otherwise:
smbpasswd [ options ] [ password ]
DESCRIPTION [Toc] [Back]
This tool 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 user's 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(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 <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.
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smbpasswd can also be used to retrieve the SIDs related to
previous incarnations of this server on the same machine, as
well as set the SID of this domain. This is needed in those
cases when the admin changes the NetBIOS or DNS name of the
server without realizing that doing so will change the SID
of the server as well. See the -W and -X options below.
OPTIONS [Toc] [Back]
-L Run the smbpasswd command in local mode. This allows a
non-root user to specify the root-only options. This is
used mostly in test environments where a non-root user
needs to make changes to the local smbpasswd file. The
smbpasswd file must have read/write permissions for the
user running the command.
-h This option prints the help string for smbpasswd.
-c smb.conf file
This option specifies that the configuration file
specified should be used instead of the default value
specified at compile time.
-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.
-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.
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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.
-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(1) program does). This option is to aid
people writing scripts to drive smbpasswd
-S This option causes smbpasswd to query a domain
controller of the domain specified by the workgroup
parameter in smb.conf and store the domain SID in the
secrets.tdb file as its own machine SID. This is only
useful when configuring a Samba PDC and Samba BDC, or
when migrating from a Windows PDC to a Samba PDC.
The -r options can be used as well to indicate a
specific domain controller which should be contacted.
In this case, the domain SID obtained is the one for
the domain to which the remote machine belongs.
-t This option is used to force smbpasswd to change the
current password assigned to the machine trust account
when operating in domain security mode. This is really
meant to be used on systems that only run winbindd
Under server installations, smbd handle the password
updates automatically.
-U username[%pass]
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. The
optional %pass may be used to specify to old password.
In particular, this parameter specifies the username
used to create the machine account when invoked with -j
-W S-1-5-21-x-y-z
This option forces the SID S-1-5-21-x-y-z to be the
server and domain SID for the current Samba server. It
does this by updating the appropriate keys in the
secrets file.
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-X server|domain
This option allows the admin to retrieve the SID
associated with a former servername or domain name that
this Samba server might have used. It does this by
retrieving the appropriate entry from the secrets file.
NOTE:
The following options are available only when the
smbpasswd command is run as root or in local mode.
-a This option specifies that the username following
should be added to the local smbpasswd file, with the
new password typed. This option is ignored if the
username specified 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.
-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 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.
-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.
-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.
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-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
-w password
This parameter is only available is Samba has been
configured to use the experimental --with-ldapsam
option. 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 private/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.
-x This option specifies that the username following
should be deleted from the local smbpasswd file.
-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.
This command can work both with and without the -U
parameter.
When invoked with -U, that username (and optional
password) are used to contact the PDC (which must be
specified with -r) to both create a machine account,
and to set a password on it.
Alternately, if -U is omitted, Samba will contact its
PDC and attempt to change the password on a preexisting
account.
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
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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.
Either way, this password is then stored by smbpasswd
in a TDB, writeable only by root, called secrets.tdb
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. The
winbindd(8) daemon can be used to create UNIX accounts
for NT users.
-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 :
o 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.
o 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 dependent. 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.
o 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.
o 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.
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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.
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.
password
This specifies the new password. If this parameter is
specified you will not be prompted for the new
password.
NOTES [Toc] [Back]
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 [Toc] [Back]
This man page is correct for version 2.2 of the Samba suite.
SEE ALSO [Toc] [Back]
smbpasswd(5) samba(7)
AUTHOR [Toc] [Back]
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/
<URL: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
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