NAME

       pam_pwhistory - PAM module to remember last passwords

SYNOPSIS

       pam_pwhistory.so [debug] [use_authtok] [enforce_for_root] [remember=N] [retry=N]
                        [authtok_type=STRING]

DESCRIPTION

       This module saves the last passwords for each user in order to force password change
       history and keep the user from alternating between the same password too frequently.

       This module does not work together with kerberos. In general, it does not make much sense
       to use this module in conjunction with NIS or LDAP, since the old passwords are stored on
       the local machine and are not available on another machine for password history checking.

OPTIONS

       debug
           Turns on debugging via syslog(3).

       use_authtok
           When password changing enforce the module to use the new password provided by a
           previously stacked password module (this is used in the example of the stacking of the
           pam_cracklib module documented below).

       enforce_for_root
           If this option is set, the check is enforced for root, too.

       remember=N
           The last N passwords for each user are saved in /etc/security/opasswd. The default is
           10. Value of 0 makes the module to keep the existing contents of the opasswd file
           unchanged.

       retry=N
           Prompt user at most N times before returning with error. The default is 1.

       authtok_type=STRING
           See pam_get_authtok(3) for more details.

MODULE TYPES PROVIDED

       Only the password module type is provided.

RETURN VALUES

       PAM_AUTHTOK_ERR
           No new password was entered, the user aborted password change or new password couldn't
           be set.

       PAM_IGNORE
           Password history was disabled.

       PAM_MAXTRIES
           Password was rejected too often.

       PAM_USER_UNKNOWN
           User is not known to system.

EXAMPLES

       An example password section would be:

           #%PAM-1.0
           password     required       pam_pwhistory.so
           password     required       pam_unix.so        use_authtok

       In combination with pam_cracklib:

           #%PAM-1.0
           password     required       pam_cracklib.so    retry=3
           password     required       pam_pwhistory.so   use_authtok
           password     required       pam_unix.so        use_authtok

FILES

       /etc/security/opasswd
           File with password history

SEE ALSO

       pam.conf(5), pam.d(5), pam(7) pam_get_authtok(3)

AUTHOR

       pam_pwhistory was written by Thorsten Kukuk <kukuk@thkukuk.de>