Apéndice Y. Archivo de configuración /etc/pamd.d/common-password

# /etc/pam.d/common-password - password-related modules common to all services
# This module type is required for updating the authentication token associated
# with the user. Typically, there is one module for each `challenge/response'
# based authentication (auth) module-type.
# This file is included from other service-specific PAM config files,
# and should contain a list of modules that define  the services to be
# used to change user passwords.  The default is pam_unix

password required	pam_cracklib.so retry=3 minlen=8 difok=4
password sufficient	pam_unix.so use_authtok md5 shadow
password sufficient	pam_ldap.so use_authtok
password required	pam_warn.so
password required	pam_deny.so