≡ Menu

shadow password

Under Linux password related utilities and config file(s) comes from shadow password suite. The /etc/login.defs file defines the site-specific configuration for this suite. 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.

You need to set default password expiry using /etc/login.defs file (password aging controls parameters):

  1. PASS_MAX_DAYS : Maximum number of days a password may be used. If the password is older than this, a password change will be forced.
  2. PASS_MIN_DAYS : Minimum number of days allowed between password changes. Any password changes attempted sooner than this will be rejected
  3. PASS_WARN_AGE : 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.

Open file /etc/login.defs using text editor:
# vi /etc/login.defs
Setup (sample) values as follows:

Close and save the file.

See also:

Please note that much of the functionality that used to be provided by the shadow password suite is now handled by PAM suite. Next time I will write about PAM configuration.