Why does PAM Security settings for passwords are not working in Red Hat Enterprise Linux 4

Issue

• system-auth file configured for password module on the server. Password length is 8 characters compriseing of one lower case character, numerical, upper case character and one other character. But the PAM restrictions are not working properly.

• Configured login.defs files for password aging control but not working.

• Set pam restrictions to remember last 5 passwords
• When changing the password for the user, need to enter new password four times

• Following are the log messages

  Feb  8 00:57:24 patchserv01 PAM-Cracklib[10502]: pam_parse: unknown option; diffok=6 
  Feb  8 00:57:24 patchserv01 passwd(pam_unix)[10502]: unrecognized option [use_authok] 
  Feb  8 00:57:30 patchserv01 PAM-Cracklib[10502]: pam_parse: unknown option; diffok=6 
  Feb  8 00:57:40 patchserv01 passwd(pam_unix)[10502]: unrecognized option [use_authok] 
  Feb  8 00:57:53 patchserv01 passwd(pam_unix)[10502]: password changed for suresh
  

• Need to enter new password four times to change a user password. Example for the user 'suresh' need to enter new password four times. Following logs are from the console.   

  passwd
  Changing password for user suresh.
  Changing password for suresh
  (current) UNIX password:
  New UNIX password:
  BAD PASSWORD: has been already used
  New UNIX password:
  Retype new UNIX password:
  Enter new UNIX password:
  Retype new UNIX password:
  passwd: all authentication tokens updated successfully.