Provided by: login_4.0.13-7ubuntu3_i386
login.defs - shadow password suite configuration
The /etc/login.defs file defines the site-specific configuration for
the shadow password suite. This file is required. Absence of this file
will not prevent system operation, but will probably result in
This file is a readable text file, each line of the file describing one
configuration parameter. The lines consist of a configuration name and
value, separated by whitespace. Blank lines and comment lines are
ignored. Comments are introduced with a ‘#’ pound sign and the pound
sign must be the first non-white character of the line.
Parameter values may be of four types: strings, booleans, numbers, and
long numbers. A string is comprised of any printable characters. A
boolean should be either the value “yes” or “no”. An undefined boolean
parameter or one with a value other than these will be given a “no”
value. Numbers (both regular and long) may be either decimal values,
octal values (precede the value with “0”) or hexadecimal values
(precede the value with “0x”). The maximum value of the regular and
long numeric parameters is machine-dependent.
The following configuration items are provided:
If yes, the chfn and chsh programs will require authentication
before making any changes, unless run by the superuser.
This parameter specifies which values in the gecos field of the
/etc/passwd file may be changed by regular users using the chfn
program. It can be any combination of letters f ,r, w, h, for
Full name, Room number, Work phone, and Home phone,
respectively. For backward compatibility, "yes" is equivalent to
"rwh" and "no" is equivalent to "frwh". If not specified, only
the superuser can make any changes. The most restrictive setting
is better achieved by not installing chfn SUID.
This defines whether useradd should create home directories for
users by default. This option is OR’ed with the -m flag on
useradd command line.
GID_MAX (number), GID_MIN (number)
Range of group IDs to choose from for the useradd and groupadd
The mail spool directory. This is needed to manipulate the
mailbox when its corresponding user account is modified or
deleted. If not specified, a compile-time default is used.
The maximum number of days a password may be used. If the
password is older than this, a password change will be forced.
If not specified, -1 will be assumed (which disables the
The minimum number of days allowed between password changes. Any
password changes attempted sooner than this will be rejected. If
not specified, -1 will be assumed (which disables the
The number of days warning given before a password expires. A
zero means warning is given only upon the day of expiration, a
negative value means no warning is given. If not specified, no
warning will be provided.
PASS_MAX_DAYS, PASS_MIN_DAYS and PASS_WARN_AGE are only used at the
time of account creation. Any changes to these settings won’t affect
UID_MAX (number), UID_MIN (number)
Range of user IDs to choose from for the useradd program.
The permission mask is initialized to this value. If not
specified, the permission mask will be initialized to 077.
If defined, this command is run when removing a user. It should
remove any at/cron/print jobs etc. owned by the user to be
removed (passed as the first argument).
The following cross reference shows which programs in the shadow
password suite use which parameters.
chfn CHFN_AUTH CHFN_RESTRICT
PASS_MAX_DAYS PASS_MIN_DAYS PASS_WARN_AGE UMASK
pwconv PASS_MAX_DAYS PASS_MIN_DAYS PASS_WARN_AGE
CREATE_HOME GID_MAX GID_MIN PASS_MAX_DAYS PASS_MIN_DAYS
PASS_WARN_AGE UID_MAX UID_MIN UMASK
Much of the functionality that used to be provided by the shadow
password suite is now handled by PAM. Thus, /etc/login.defs is no
longer used by programs such as: login(1), passwd(1), su(1). Please
refer to the corresponding PAM configuration files instead.
login(1), passwd(1), su(1), passwd(5), shadow(5), pam(8).
Julianne Frances Haugh (email@example.com) Chip Rosenthal