auth		required	pam_env.so 
auth		required	pam_unix.so try_first_pass likeauth nullok 
auth		optional	pam_permit.so
 
account		required	pam_unix.so 
account		optional	pam_permit.so
 
password	required	pam_cracklib.so difok=2 minlen=8 dcredit=2 ocredit=2 retry=3 
password	required	pam_unix.so try_first_pass use_authtok nullok sha512 shadow 
password	optional	pam_permit.so
 
session		required	pam_limits.so 
session		required	pam_env.so 
session		required	pam_unix.so 
session		optional	pam_permit.so
