auth		required	pam_env.so 
auth		sufficient	pam_unix.so try_first_pass likeauth nullok 
auth		required	pam_deny.so
 
account		required	pam_unix.so 
 
password	required	pam_unix.so try_first_pass  nullok sha512 shadow 
 
session		required	pam_limits.so 
session		required	pam_env.so 
session		required	pam_unix.so 
session		optional	pam_permit.so