transactions of the world's most important business runs on a Unix machine, which means the machines running those transactions attract evildoers. In addition, many machines have Internet connections, which means it is always possible that some malicious remote user will find its way into the third edition of Practical Unix & Internet Security contains - to a greater extent even than the famous ancestor of all large-amount policies accumulated about how to protect Internet-connected Unix machines from intrusion and other forms of attack. This book is fat with practical advice on specific defensive measures (to defeat known attacks) and generally wise policies (to prevent people who have not been found). Authors approach to Unix security is holistic and clever, they devote much space to the security philosophy to advice about closing TCP ports and disable unnecessary services.