234 lines
7.4 KiB
Groff
234 lines
7.4 KiB
Groff
.\" Copyright (c) 1990, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)passwd.1 8.1 (Berkeley) 6/6/93
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.\" $Id: passwd.1,v 1.14 1999/04/30 18:19:42 hoek Exp $
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.\"
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.Dd June 6, 1993
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.Dt PASSWD 1
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.Os BSD 4
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.Sh NAME
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.Nm passwd, yppasswd
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.Nd modify a user's password
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.Sh SYNOPSIS
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.Nm passwd
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.Op Fl l
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.Op Ar user
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.Nm yppasswd
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.Op Fl l
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.Op Fl y
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.Op Fl d Ar domain
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.Op Fl h Ar host
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.Op Fl o
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.Sh DESCRIPTION
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.Nm Passwd
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changes the user's local, Kerberos, or NIS password.
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If the user is not the super-user,
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.Nm passwd
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first prompts for the current password and will not continue unless the correct
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password is entered.
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.Pp
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When entering the new password, the characters entered do not echo, in order to
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avoid the password being seen by a passer-by.
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.Nm passwd
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prompts for the new password twice in order to detect typing errors.
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.Pp
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The new password should be at least six characters long (which
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may be overridden using the
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.Xr login.conf 5
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.if t ``minpasswordlen''
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.if n "minpasswordlen"
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setting for a user's login class) and not purely alphabetic.
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Its total length must be less than
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.Dv _PASSWORD_LEN
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(currently 128 characters).
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Numbers, upper case letters and meta characters
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are encouraged.
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.Pp
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Once the password has been verified,
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.Nm passwd
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communicates the new password information to
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the Kerberos authenticating host.
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.Bl -tag -width flag
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.It Fl l
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This option causes the password to be updated only in the local
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password file, and not with the Kerberos database.
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When changing only the local password,
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.Xr pwd_mkdb 8
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is used to update the password databases.
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.Pp
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.El
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When changing local or NIS password, the next password change date
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is set according to
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.if t ``passwordtime''
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.if n "passwordtime"
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capability in the user's login class.
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.Pp
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To change another user's Kerberos password, one must first
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run
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.Xr kinit 1
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followed by
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.Xr passwd 1 .
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The super-user is not required to provide a user's current password
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if only the local password is modified.
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.Sh NIS INTERACTION
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.Nm Passwd
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has built-in support for NIS. If a user exists in the NIS password
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database but does not exist locally,
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.Nm passwd
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automatically switches into
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.if t ``yppasswd''
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.if n "yppasswd"
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mode. If the specified
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user does not exist in either the local password database of the
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NIS password maps,
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.Nm passwd
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returns an error.
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.Pp
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When changing an NIS password, unprivileged users are required to provide
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their old password for authentication (the
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.Xr rpc.yppasswdd 8
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daemon requires the original password before
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it will allow any changes to the NIS password maps).
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This restriction applies even to the
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super-user, with one important exception: the password authentication is
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bypassed for the super-user on the NIS master server. This means that
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the super-user on the NIS master server can make unrestricted changes to
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anyone's NIS password. The super-user on NIS client systems and NIS slave
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servers still needs to provide a password before the update will be processed.
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.Pp
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The following additional options are supported for use with NIS:
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.Bl -tag -width flag
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.It Fl y
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The
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.Fl y
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flag overrides
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.Nm passwd 's
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checking heuristics and forces
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it into NIS mode.
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.It Fl l
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When NIS is enabled, the
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.Fl l
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flag can be used to force
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.Nm passwd
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into
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.if t ``local only''
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.if n "local only"
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mode. This flag can be used to change the entry
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for a local user when an NIS user exists with the same login name.
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For example, you will sometimes find entries for system
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.if t ``placeholder''
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.if n "placeholder"
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users such as
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.Pa bin
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or
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.Pa daemon
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in both the NIS password maps and the local user database. By
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default,
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.Nm passwd
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will try to change the NIS password. The
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.Fl l
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flag can be used to change the local password instead.
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.It Fl d Ar domain
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Specify what domain to use when changing an NIS password. By default,
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.Nm passwd
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assumes that the system default domain should be used. This flag is
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primarily for use by the superuser on the NIS master server: a single
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NIS server can support multiple domains. It is also possible that the
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domainname on the NIS master may not be set (it is not necessary for
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an NIS server to also be a client) in which case the
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.Nm passwd
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command needs to be told what domain to operate on.
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.It Fl s Ar host
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Specify the name of an NIS server. This option, in conjunction
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with the
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.Fl d
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option, can be used to change an NIS password on a non-local NIS
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server. When a domain is specified with the
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.Fl d
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option and
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.Nm passwd
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is unable to determine the name of the NIS master server (possibly because
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the local domainname isn't set), the name of the NIS master is assumed to
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be
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.if t ``localhost''.
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.if n "localhost".
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This can be overidden with the
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.Fl s
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flag. The specified hostname need not be the name of an NIS master: the
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name of the NIS master for a given map can be determined by querying any
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NIS server (master or slave) in a domain, so specifying the name of a
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slave server will work equally well.
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.Pp
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.It Fl o
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Do not automatically override the password authentication checks for the
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super-user on the NIS master server; assume 'old' mode instead. This
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flag is of limited practical use but is useful for testing.
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.El
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.Sh FILES
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.Bl -tag -width /etc/master.passwd -compact
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.It Pa /etc/master.passwd
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The user database
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.It Pa /etc/passwd
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A Version 7 format password file
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.It Pa /etc/passwd.XXXXXX
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Temporary copy of the password file
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.It Pa /etc/login.conf
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Login class capabilities database
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.It Pa /etc/auth.conf
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configure authentication services
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.El
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.Sh SEE ALSO
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.Xr chpass 1 ,
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.Xr kerberos 1 ,
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.Xr kinit 1 ,
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.Xr login 1 ,
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.Xr login.conf 5 ,
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.Xr passwd 5 ,
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.Xr kpasswdd 8 ,
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.Xr pwd_mkdb 8 ,
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.Xr vipw 8
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.Rs
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.%A Robert Morris
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.%A Ken Thompson
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.%T "UNIX password security"
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.Re
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.Sh NOTES
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The
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.Xr yppasswd 1
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command is really only a link to
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.Nm passwd .
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.Sh HISTORY
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A
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.Nm passwd
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command appeared in
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.At v6 .
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