[...]... firewall serves and the basics of configuring a firewall 2 Firewalls For Dummies, 2nd Edition About This Book We try to provide you with a book that can act as a reference guide for firewalls We don’t expect you to read the book from cover to cover but to look at specific topics that meet your needs Twenty chapters and an appendix cover all topics of firewalls and their implementation Just turn to the chapter... out about firewalls Sidebars and extra information included in the book provide additional information that can help you, but you don’t need to read them to use firewalls This additional information is marked with the Technical Stuff icon However, if you want that extra technical information, you now know where to find it! Foolish Assumptions When we sat down to come up with the outline for this book,... process of determining what protocols to allow in and out of your network If you don’t have guidelines for securing your network, coming up with a configuration for your firewall is almost impossible! 3 4 Firewalls For Dummies, 2nd Edition Part III: Designing Network Configurations Put on your helmets for a trip to the world of Demilitarized Zones (the computer kind, not the combat kind) Part III puts... Policy 118 Setting a Security policy 118 Chapter 7: Establishing Rules for Simple Protocols 121 For Starters, Some Default Rules .123 Allowing Web Access 123 Configuring inbound firewall rules 125 Configuring outbound firewall rules .126 xi xii Firewalls For Dummies, 2nd Edition Finding Internet Resources 126 Providing name resolution to Internet-based... Sharing: NAT for Dummies 218 Windows NT 4.0 221 Packet filtering 222 PPTP server 223 Windows 2000 224 Packet filtering 224 Network Address Translation (NAT) .227 L2TP and IPSec 229 Windows XP 230 Internet Connection Firewall (ICF) 231 Windows Server 2003 232 xiii xiv Firewalls For Dummies, 2nd Edition... of Contents, find a topic that interests you, and go to that chapter If you’re looking for configuration details for specific firewalls, jump to Part IV where we provide detailed steps on how to install and configure popular firewall products used today If you’re just looking for tips on how to configure a firewall for specific protocols, Parts II and III look at simple and advanced protocol rules in... memorize a topic related to firewalls Tips provide you with inside information on how to quickly configure a rule or get past a common hurdle when designing firewalls Where to Go from Here You have the book in your hand, and you’re ready to get started Feel free to turn to any topic in the book that interests you! Look in the Table of Contents for the topic that drew your interest to firewalls If you’re not... to firewalls If you’re not curious about any specific topic but just want an overview, turn the page and start with Part I Either way, enjoy yourself and let us help you learn about firewalls! 5 6 Firewalls For Dummies, 2nd Edition Part I Introducing Firewall Basics F In this part irewalls — who needs ’em? Well it turns out, most of us do If you or your company is connected to the Internet, you may... nowhere to be found; for them the problem had been solved — the virus was gone For everyone else the problem had just started ߜ Hijacked computer: Imagine that someone broke into your computer and used it for his own purposes If your computer is not used much anyway, this may not seem like a big deal However, now imagine that the intruder uses your computer for illegitimate purposes For example, a hacker... computer to another using TCP/IP includes information on what IP address the data comes from and what IP address it is being sent to TCP/IP defines the methods that computers connected to the Internet use to transmit information This includes dividing this information in small manageable chunks called packets Each packet contains header information and data Most firewalls examine the packet header to determine