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DNS for Dummies - Books24x7.com - Referenceware for Professionals Page 1 of 1 Introduction DNS for Dummies by Blair Rampling and David Dalan John Wiley & Sons © 2003 Introduction Welcome to DNS For Dummies! This is the book you have always wanted if you have ever needed to understand DNS or you need to set up and configure a DNS server and you haven't had the opportunity to learn the ropes yet. Admittedly, DNS can be a daunting hill to climb. Traditional DNS documentation assumes that you're an expert on the Internet and its protocols, such as TCP/IP, and it uses lots of big words and technical jargon. In DNS For Dummies, we avoid that kind of intimidating language in favor of information that anyone can decipher. About This Book This book isn't meant to be a thorough technical overview of DNS, although it does that job admirably. If you just need to get your toes wet on the topic of DNS, you may be especially interested in Chapters 1-4 because they build a basis for exploring the more technical theory described in the following chapters. If you want, though, you can skip those chapters and jump right into our description of how to install and configure a DNS server. When you need to perform a task with DNS as either a client or a server, you can pick up the book, turn to the section you need, and start from there. You don't need lots of knowledge to be able to jump into any section because the walk-through examples for each procedure are detailed. Use of content on this site is expressly subject to the restrictions set forth in the Membership Agreement. Books24x7 and Referenceware are registered trademarks of Books24x7, Inc. Copyright © 1999-2006 Books24x7, Inc. - Feedback | Privacy Policy (updated 03/2005) RSS feed http://www.books24x7.com/book/id_12254/viewer_r.asp?bookid=12254&chunkid=84768... 1/26/2007 DNS for Dummies - Books24x7.com - Referenceware for Professionals Page 1 of 1 Introduction DNS for Dummies by Blair Rampling and David Dalan John Wiley & Sons © 2003 How to Use This Book This book is designed to be used as a practical guide to implementing and maintaining DNS on Windows- family servers and Unix-based servers. Additionally, if you're exploring the possibilities of building your own DNS server, this book contains information that demystifies the inner workings of DNS. As a working reference, this book contains the needed information that will help you configure your DNS server initially and continue supporting it long afterward. This text is a job aid, a handy and insightful reference you can use for answering DNS configuration- and maintenance-related questions in a hurry. In addition to its wealth of information, DNS For Dummies contains tips for getting additional information about particular topics related to DNS. Use of content on this site is expressly subject to the restrictions set forth in the Membership Agreement. Books24x7 and Referenceware are registered trademarks of Books24x7, Inc. Copyright © 1999-2006 Books24x7, Inc. - Feedback | Privacy Policy (updated 03/2005) RSS feed http://www.books24x7.com/book/id_12254/viewer_r.asp?bookid=12254&chunkid=20265... 1/26/2007 DNS for Dummies - Books24x7.com - Referenceware for Professionals Page 1 of 1 Introduction DNS for Dummies by Blair Rampling and David Dalan John Wiley & Sons © 2003 What You Don't Need to Read A number of sections in this book are highly technical because DNS is a technical subject. You don't have to read anything that's in a sidebar or marked with a Technical Stuff icon to be able to use DNS clients or servers; reading those sections, however, can further your understanding of how DNS works behind the scenes. In addition, several chapters are dedicated to the theory behind how DNS works. You get a better understanding of why DNS does certain things if you understand how the DNS process works. If you choose to skip Chapters 3 and 4 because of their technical nature, however, you won't miss the "meat" of working with DNS. Use of content on this site is expressly subject to the restrictions set forth in the Membership Agreement. Books24x7 and Referenceware are registered trademarks of Books24x7, Inc. Copyright © 1999-2006 Books24x7, Inc. - Feedback | Privacy Policy (updated 03/2005) RSS feed http://www.books24x7.com/book/id_12254/viewer_r.asp?bookid=12254&chunkid=19088... 1/26/2007 DNS for Dummies - Books24x7.com - Referenceware for Professionals Page 1 of 1 Introduction DNS for Dummies by Blair Rampling and David Dalan John Wiley & Sons © 2003 Foolish Assumptions In writing this book, we have assumed that you're a somewhat technically literate user who is already familiar with the Internet to some extent. Although this book attempts to simplify DNS, it's still a technical subject at heart. Without a firm grasp of the basics of the Internet, you don't have much hope of understanding DNS. You should be familiar with terms such as WWW, e-mail, and IP address. We have assumed also that you're somewhat comfortable with the operating system you're using—either Microsoft Windows or Unix/Linux. You should at least be able to navigate in Windows and use the basic configuration tools or be somewhat comfortable in a Unix shell and be able to view and edit files. Use of content on this site is expressly subject to the restrictions set forth in the Membership Agreement. Books24x7 and Referenceware are registered trademarks of Books24x7, Inc. Copyright © 1999-2006 Books24x7, Inc. - Feedback | Privacy Policy (updated 03/2005) RSS feed http://www.books24x7.com/book/id_12254/viewer_r.asp?bookid=12254&chunkid=54133... 1/26/2007 DNS for Dummies - Books24x7.com - Referenceware for Professionals Page 1 of 2 Introduction DNS for Dummies by Blair Rampling and David Dalan John Wiley & Sons © 2003 How This Book Is Organized This book is organized into five parts. The parts separate the content of the book into activities such as working with clients or servers and configuring DNS zones. Each part is made up of a series of chapters, each divided into sections. You can start reading at any part or chapter in the book if you're interested in performing a certain task. The five parts are described next. Part I: How DNS Makes the Internet Go ‘Round You may or may not know that DNS is at the heart of the Internet. Almost every application on the Net uses DNS in one way or another. This part explains what DNS is, how DNS names are organized on the Internet, and how DNS works in theory. Part II: Working with DNS Clients Every system has DNS clients of some sort. Part II explains which DNS clients exist on your systems and how to use those clients. A chapter apiece is devoted to configuring DNS clients on your system and using those clients. Part III: Working with DNS Servers If you have ever wanted (or needed) to run your own DNS server, all the information you need is in Part III. One of its two chapters is devoted to installing and configuring a DNS server on Microsoft Windows; the other, to installing and configuring the BIND 9 DNS server on Linux or Unix. Part IV: The Details: Setting Up YourDNS Zones Every DNS server that isn't devoted purely to caching DNS entries has one or more zones. A zone contains all the information for a specific domain. If you need to add records to a zone, create a new zone, or even create a subdomain, Part IV is the place. It even explains how zones work and describes the major types of DNS records. Part V: Security and Advanced DNS Tricks If you want to do something extraordinary with your DNS server or you simply want to make it as secure as possible, Part V is for you. It covers the security problems faced by DNS and how to make sure that you aren't susceptible to those problems. This part also covers the advanced features in DNS servers and troubleshooting. Part VI: The Part of Tens Part VI talks about a variety of DNS-related subjects that may just tickle your fancy. From ten things even "experts" do to inadvertently trash their DNS servers to ten steps that can keep you chugging down the road to DNS nirvana, we give you all kinds of concise and relevant information. If you find yourself in http://www.books24x7.com/book/id_12254/viewer_r.asp?bookid=12254&chunkid=40776... 1/26/2007 DNS for Dummies - Books24x7.com - Referenceware for Professionals Page 2 of 2 need of a quick solution, this part of the book can be a life-saver. Appendixes The appendixes provide information beyond the normal scope of what you probably will do with your DNS servers. This information includes the use of the DNSCMD utility to administer your Windows DNS server from the command line, the use of Webmin to administer your UNIX DNS server graphically, and a list of available DNS server applications other than the Microsoft DNS Server and BIND, which are covered in this book. Use of content on this site is expressly subject to the restrictions set forth in the Membership Agreement. Books24x7 and Referenceware are registered trademarks of Books24x7, Inc. Copyright © 1999-2006 Books24x7, Inc. - Feedback | Privacy Policy (updated 03/2005) RSS feed http://www.books24x7.com/book/id_12254/viewer_r.asp?bookid=12254&chunkid=40776... 1/26/2007 DNS for Dummies - Books24x7.com - Referenceware for Professionals Page 1 of 1 Introduction DNS for Dummies by Blair Rampling and David Dalan John Wiley & Sons © 2003 Icons Used In This Book Keep this information in mind while working with your DNS server. Although the information may not seem relevant in some situations, when you do need it, it's a life-saver. You're delving into the deepest reaches of DNS server administration. Although this information isn't needed regularly in most cases, it does give you insight into the workings of the particular technology being examined. This stuff is generally handy in the day-to-day operation of your server. To visit DNS nirvana, avoid these common traps, shortcomings, or issues. Use of content on this site is expressly subject to the restrictions set forth in the Membership Agreement. Books24x7 and Referenceware are registered trademarks of Books24x7, Inc. Copyright © 1999-2006 Books24x7, Inc. - Feedback | Privacy Policy (updated 03/2005) RSS feed http://www.books24x7.com/book/id_12254/viewer_r.asp?bookid=12254&chunkid=23380... 1/26/2007 DNS for Dummies - Books24x7.com - Referenceware for Professionals Page 1 of 1 Introduction DNS for Dummies by Blair Rampling and David Dalan John Wiley & Sons © 2003 Where to Go from Here DNS is a technical subject. By picking up this book, however, you have taken the first step to bridging the gap from Internet user to someone who truly understands the hows and whys of the Internet. Start anywhere you want in this book—just take a look at the table of contents or the index, and enjoy taking control of your Internet experience! Use of content on this site is expressly subject to the restrictions set forth in the Membership Agreement. Books24x7 and Referenceware are registered trademarks of Books24x7, Inc. Copyright © 1999-2006 Books24x7, Inc. - Feedback | Privacy Policy (updated 03/2005) RSS feed http://www.books24x7.com/book/id_12254/viewer_r.asp?bookid=12254&chunkid=68830... 1/26/2007 DNS for Dummies - Books24x7.com - Referenceware for Professionals Page 1 of 1 Part I - How DNS Makes the Internet Go ‘Round DNS for Dummies by Blair Rampling and David Dalan John Wiley & Sons © 2003 Part I: How DNS Makes the Internet Go ‘Round Chapter List Chapter 1: The Basics of DNS Chapter 2: DNS Namespaces Chapter 3: The DNS Request Process Chapter 4: Facilitating Other Applications with DNS In this part ………… You may be familiar with DNS, or, like many users of the Internet and corporate networks, you may be blissfully unaware of what DNS is. Many users have no idea that DNS even exists. The chapters in this part of the book introduce you to the basics of DNS, from how it works by itself (its internal processes, for example) to how it enables other applications to provide useful services to users. We even give you a step-by-step description of the processes that go on behind the scenes whenever you use an application that relies on DNS, such as a Web browser. Use of content on this site is expressly subject to the restrictions set forth in the Membership Agreement. Books24x7 and Referenceware are registered trademarks of Books24x7, Inc. Copyright © 1999-2006 Books24x7, Inc. - Feedback | Privacy Policy (updated 03/2005) RSS feed http://www.books24x7.com/book/id_12254/viewer_r.asp?bookid=12254&chunkid=62589... 1/26/2007 DNS for Dummies - Books24x7.com - Referenceware for Professionals Page 1 of 1 Chapter 1 - The Basics of DNS DNS for Dummies by Blair Rampling and David Dalan John Wiley & Sons © 2003 Chapter 1: The Basics of DNS Overview Unless you have been living in a cave, you have probably heard about the Internet. In homes and offices across the world, the Internet is fast becoming as ubiquitous as telephones and televisions. It has experienced rapid growth in large part because of a number of popular Internet-based applications, including the World Wide Web, e-mail, and instant messaging. One reason that a typical "nontechy" user can enjoy the Internet is that many of the details of connecting a computer to the Internet are hidden from general users. Almost anyone can browse the Web or send and receive e-mail without understanding anything about how the Internet works. This ease of use is an important factor in our discussion of DNS in this book. Simply put, DNS allows people to use meaningful names, such as http://www.yahoo.com, to find Internet-based resources. In this way, DNS has allowed users from a wide range of educational backgrounds to makes use of the Internet. That wasn't always the case. In the beginning, the Internet was simply a method for government and educational institutions to talk to each other. At the time, only computer experts could use it because they possessed the knowledge needed to connect one computer to another on this "primitive" Internet. Restricting use of the Internet to expert users wasn't good enough. Many hosts participating in the early Internet were located at, and supported by staff members from, universities. Universities (notably, the University of California at Berkley) wanted to make use of this tool to help perform research and teach. Even though most users were computer specialists, the number of hosts added to the budding Internet would be too numerous to track manually. With the invention of a number of network protocols that worked behind the scenes to remove much of the manual interaction on the Internet, ease of use was greatly improved. These protocols included, among others, the Domain Name System, or DNS. DNS eliminated the need to manually remember IP addresses and replaced that system with human-readable names instead. DNS allows a name to be linked to an address and rather than have to remember a number of addresses, you need to know just the name of the system you want to contact. Although DNS plays quite a significant role in millions of users' daily Internet use, this ease of use is a side effect of the original intention of DNS. DNS was invented to solve the logistical problems that arose because too many hosts were on the Internet to be able to keep track of using a manual list of addresses. Use of content on this site is expressly subject to the restrictions set forth in the Membership Agreement. Books24x7 and Referenceware are registered trademarks of Books24x7, Inc. Copyright © 1999-2006 Books24x7, Inc. - Feedback | Privacy Policy (updated 03/2005) RSS feed http://www.books24x7.com/book/id_12254/viewer_r.asp?bookid=12254&chunkid=30928... 1/26/2007