I would like to know if you or anyone else in the expert group have ever used the progeam called JOHN THE RIPPER to I want to install it and do some security checks (passwords for other users) . If you have used it before could you please give me the pro's and con's using this software. A book I'm reading now is call REAL WORLD LINUX SECURITY, Intrusion Prevention, Detection, and Recovery. by Bob Toxen, and it suggested I try using it to see how secure the passwords my friends employees are using. also if anyone has read the book linux hacking exposed, please give me your feedback. Thanks for your help. Sincerely, Gavin (Japan)