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Summary
The importance of security began to 'hit home' with network administrators years ago, but the events of the new millennium - including both an increased level of cyber-attacks and the physical attacks on the United States and its allies here and abroad - have heightened our awareness that today's world is a dangerous place and that danger extends to the computer networks that hold data on which many aspects of our lives depend. Protecting digital assets has become a top priority for businesses and individuals, and a key element in protecting any computer that connects to a network (and that includes most of them these days) is the firewall.
ISA Server 2004 has its origins in Microsoft Proxy Server, and later, ISA Server 2000, but Microsoft sees it as an entirely new product. The user interface has been completely changed, key features have been added (and some features have been removed), and ISA has grown into a full-fledged firewall that is designed to compete with the 'big guys' in the firewall industry, both enterprise-level software firewalls and appliance-type hardware firewall devices.
Microsoft's reputation when it comes to security has suffered because of an early emphasis on features and functionality at the expense of security. However, the company has done a complete turnaround in priorities and today spends millions of dollars on security each year. The Trustworthy Computing initiative, with its SD3 - Secure by Design, Secure by Default, Secure in Deployment - three-pronged goal puts an emphasis on security that has been incorporated into the design of ISA Server 2004 at every level.
ISA Server 2004 takes a policy-based approach to security and makes it easy for administrators to enforce the security policies decided upon by management. Developing appropriate policies is a key step in planning your firewall deployment, and that includes evaluating security needs, analyzing risk factors, assessing threats and threat levels, analyzing organizational and network vulnerabilities, analyzing organizational factors that affect security, analyzing legal factors, and finally, analyzing cost factors.
In order to be effective, a good security plan must take a multilayered approach. This means recognizing that most networks contain more than one perimeter and implementing multiple security measures (which may include multiple firewalls) to best protect the important assets (mission-critical applications and data) at the core of the network.
Firewalls act as the guardians at the gateway (the entrance to the network or subnet). The first firewalls were simple packet-filtering devices, but today's sophisticated multilayered firewalls can filter at the network, transport, and application layers of the OSI networking model to provide security coverage on a much broader scale. ISA Server 2004 is a packet-filtering, circuit-filtering and application-layer-filtering network-based software firewall that also includes VPN gateway functionality, intrusion detection and prevention, and Web caching to accelerate performance for both internal and external users.
ISA Server 2004 includes many new features, and improvements and enhancements have been made to many of the features that it shares with ISA 2000. As you go through this book, you will first learn the concepts behind the latest incarnation of ISA, then you'll learn how to install, configure, manage, use, and troubleshoot it in a detailed, step-by-step fashion.
Let's begin!
