Skip site navigation (1)Skip section navigation (2)

FreeBSD Man Pages

Man Page or Keyword Search:
Man Architecture
Apropos Keyword Search (all sections) Output format
home | help
PASSWD(1)		FreeBSD	General	Commands Manual		     PASSWD(1)

NAME
     passwd, yppasswd -- modify	a user's password

SYNOPSIS
     passwd [-l] [user]
     yppasswd [-l] [-y]	[-d domain] [-h	host] [-o]

DESCRIPTION
     The passwd	utility	changes	the user's local, Kerberos, or NIS password.
     If	the user is not	the super-user,	passwd first prompts for the current
     password and will not continue unless the correct password	is entered.

     When entering the new password, the characters entered do not echo, in
     order to avoid the	password being seen by a passer-by.  The passwd	util-
     ity prompts for the new password twice in order to	detect typing errors.

     The new password should be	at least six characters	long (which may	be
     overridden	using the login.conf(5)	``minpasswordlen'' setting for a
     user's login class) and not purely	alphabetic.  Its total length must be
     less than _PASSWORD_LEN (currently	128 characters).

     The new password should contain a mixture of upper	and lower case charac-
     ters (which may be	overridden using the login.conf(5) ``mixpasswordcase''
     setting for a user's login	class).	 Allowing lower	case passwords may be
     useful where the password file will be used in situations where only
     lower case	passwords are permissible, such	as when	using Samba to authen-
     ticate Windows clients.  In all other situations, numbers,	upper case
     letters and meta characters are encouraged.

     Once the password has been	verified, passwd communicates the new password
     information to the	Kerberos authenticating	host.

     The following option is available:

     -l	     Cause the password	to be updated only in the local	password file,
	     and not with the Kerberos database.  When changing	only the local
	     password, pwd_mkdb(8) is used to update the password databases.
     When changing local or NIS	password, the next password change date	is set
     according to ``passwordtime'' capability in the user's login class.

     To	change another user's Kerberos password, one must first	run kinit(1)
     followed by passwd.  The super-user is not	required to provide a user's
     current password if only the local	password is modified.

NIS INTERACTION
     The passwd	utility	has built-in support for NIS.  If a user exists	in the
     NIS password database but does not	exist locally, passwd automatically
     switches into ``yppasswd''	mode.  If the specified	user does not exist in
     either the	local password database	of the NIS password maps, passwd
     returns an	error.

     When changing an NIS password, unprivileged users are required to provide
     their old password	for authentication (the	rpc.yppasswdd(8) daemon
     requires the original password before it will allow any changes to	the
     NIS password maps).  This restriction applies even	to the super-user,
     with one important	exception: the password	authentication is bypassed for
     the super-user on the NIS master server.  This means that the super-user
     on	the NIS	master server can make unrestricted changes to anyone's	NIS
     password.	The super-user on NIS client systems and NIS slave servers
     still needs to provide a password before the update will be processed.

     The following additional options are supported for	use with NIS:

     -y	     Override passwd's checking	heuristics and forces it into NIS
	     mode.

     -l	     When NIS is enabled, the -l flag can be used to force passwd into
	     ``local only'' mode.  This	flag can be used to change the entry
	     for a local user when an NIS user exists with the same login
	     name.  For	example, you will sometimes find entries for system
	     ``placeholder'' users such	as bin or daemon in both the NIS pass-
	     word maps and the local user database.  By	default, passwd	will
	     try to change the NIS password.  The -l flag can be used to
	     change the	local password instead.

     -d	domain
	     Specify what domain to use	when changing an NIS password.	By
	     default, passwd assumes that the system default domain should be
	     used.  This flag is primarily for use by the superuser on the NIS
	     master server: a single NIS server	can support multiple domains.
	     It	is also	possible that the domainname on	the NIS	master may not
	     be	set (it	is not necessary for an	NIS server to also be a
	     client) in	which case the passwd command needs to be told what
	     domain to operate on.

     -h	host
	     Specify the name of an NIS	server.	 This option, in conjunction
	     with the -d option, can be	used to	change an NIS password on a
	     non-local NIS server.  When a domain is specified with the	-d
	     option and	passwd is unable to determine the name of the NIS mas-
	     ter server	(possibly because the local domainname is not set),
	     the name of the NIS master	is assumed to be ``localhost''.	 This
	     can be overridden with the	-h flag.  The specified	hostname need
	     not be the	name of	an NIS master: the name	of the NIS master for
	     a given map can be	determined by querying any NIS server (master
	     or	slave) in a domain, so specifying the name of a	slave server
	     will work equally well.

     -o	     Do	not automatically override the password	authentication checks
	     for the super-user	on the NIS master server; assume 'old' mode
	     instead.  This flag is of limited practical use but is useful for
	     testing.

FILES
     /etc/master.passwd	 the user database
     /etc/passwd	 a Version 7 format password file
     /etc/passwd.XXXXXX	 temporary copy	of the password	file
     /etc/login.conf	 login class capabilities database
     /etc/auth.conf	 configure authentication services

SEE ALSO
     chpass(1),	kinit(1), login(1), login.conf(5), passwd(5), kerberos(8),
     kpasswdd(8), pw(8), pwd_mkdb(8), vipw(8)

     Robert Morris and Ken Thompson, UNIX password security.

NOTES
     The yppasswd command is really only a link	to passwd.

HISTORY
     A passwd command appeared in Version 6 AT&T UNIX.

FreeBSD	6.0			 June 6, 1993			   FreeBSD 6.0

NAME | SYNOPSIS | DESCRIPTION | NIS INTERACTION | FILES | SEE ALSO | NOTES | HISTORY

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=passwd&sektion=1&manpath=FreeBSD+6.0-RELEASE>

home | help