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28 .\" @(#)passwd.1 8.1 (Berkeley) 6/6/93
36 .Nd modify a user's password
50 utility changes the user's local, Kerberos, or NIS password.
51 If the user is not the super-user,
53 first prompts for the current password and will not continue unless the correct
56 When entering the new password, the characters entered do not echo, in order to
57 avoid the password being seen by a passer-by.
60 utility prompts for the new password twice in order to detect typing errors.
62 The new password should be at least six characters long (which
63 may be overridden using the
66 setting for a user's login class) and not purely alphabetic.
67 Its total length must be less than
69 (currently 128 characters).
71 The new password should contain a mixture of upper and lower case
72 characters (which may be overridden using the
75 setting for a user's login class).
76 Allowing lower case passwords may
77 be useful where the password file will be used in situations where only
78 lower case passwords are permissible, such as when using Samba to
79 authenticate Windows clients.
80 In all other situations, numbers, upper
81 case letters and meta characters are encouraged.
83 Once the password has been verified,
85 communicates the new password information to
86 the Kerberos authenticating host.
88 The following option is available:
89 .Bl -tag -width indent
91 Cause the password to be updated only in the local
92 password file, and not with the Kerberos database.
93 When changing only the local password,
95 is used to update the password databases.
98 When changing local or NIS password, the next password change date
101 capability in the user's login class.
103 To change another user's Kerberos password, one must first
108 The super-user is not required to provide a user's current password
109 if only the local password is modified.
113 utility has built-in support for NIS.
114 If a user exists in the NIS password
115 database but does not exist locally,
117 automatically switches into
121 user does not exist in either the local password database or the
126 When changing an NIS password, unprivileged users are required to provide
127 their old password for authentication (the
129 daemon requires the original password before
130 it will allow any changes to the NIS password maps).
131 This restriction applies even to the
132 super-user, with one important exception: the password authentication is
133 bypassed for the super-user on the NIS master server.
135 the super-user on the NIS master server can make unrestricted changes to
136 anyone's NIS password.
137 The super-user on NIS client systems and NIS slave
138 servers still needs to provide a password before the update will be processed.
140 The following additional options are supported for use with NIS:
141 .Bl -tag -width indent
145 checking heuristics and forces
148 When NIS is enabled, the
150 flag can be used to force
155 This flag can be used to change the entry
156 for a local user when an NIS user exists with the same login name.
157 For example, you will sometimes find entries for system
163 in both the NIS password maps and the local user database.
167 will try to change the NIS password.
170 flag can be used to change the local password instead.
172 Specify what domain to use when changing an NIS password.
175 assumes that the system default domain should be used.
177 primarily for use by the superuser on the NIS master server: a single
178 NIS server can support multiple domains.
179 It is also possible that the
180 domainname on the NIS master may not be set (it is not necessary for
181 an NIS server to also be a client) in which case the
183 command needs to be told what domain to operate on.
185 Specify the name of an NIS server.
186 This option, in conjunction
189 option, can be used to change an NIS password on a non-local NIS
191 When a domain is specified with the
195 is unable to determine the name of the NIS master server (possibly because
196 the local domainname is not set), the name of the NIS master is assumed to
199 This can be overridden with the
202 The specified hostname need not be the name of an NIS master: the
203 name of the NIS master for a given map can be determined by querying any
204 NIS server (master or slave) in a domain, so specifying the name of a
205 slave server will work equally well.
207 Do not automatically override the password authentication checks for the
208 super-user on the NIS master server; assume
212 flag is of limited practical use but is useful for testing.
215 .Bl -tag -width /etc/master.passwd -compact
216 .It Pa /etc/master.passwd
219 a Version 7 format password file
220 .It Pa /etc/passwd.XXXXXX
221 temporary copy of the password file
222 .It Pa /etc/login.conf
223 login class capabilities database
239 .%T "UNIX password security"
244 command is really only a link to