Book excerpt: As organizations today are linking their systems across enterprise-wide networks and VPNs as well as increasing their exposure to customers, competitors, browsers and hackers on the Internet, it becomes increasingly imperative for Web professionals to be trained in techniques for effectively protecting their sites from internal and external threats. Each connection magnifies the vulnerability to attack. With the increased connectivity to the Internet and the wide availability of automated cracking tools, organizations can no longer simply rely on operating system security to protect their valuable corporate data. Furthermore, the exploding use of Web technologies for corporate intranets and Internet sites has escalated security risks to corporate data and information systems. Practical Internet Security reveals how the Internet is paving the way for secure communications within organizations and on the public Internet. This book provides the fundamental knowledge needed to analyze risks to a system and to implement a security policy that protects information assets from potential intrusion, damage, or theft. It provides dozens of real-life scenarios and examples, as well as hands-on instruction in securing Web communications and sites. You will learn the common vulnerabilities of Web sites; as well as, how to carry out secure communications across unsecured networks. All system administrators and IT security managers will find this book an essential practical resource.