Book Image

DNS in Action

By : CP Books a.s.
Book Image

DNS in Action

By: CP Books a.s.

Overview of this book

The Domain Name System is one of the foundations of the internet. It is the system that allows the translation of human-readable domain names into machines-readable IP addresses and the reverse translation of IP addresses into domain names. This book describes the basic DNS protocol and its extensions; DNS delegation and registration, including for reverse domains; using DNS servers in networks that are not connected to the internet; and using DNS servers on firewall machines. Many detailed examples are used throughout the book to show perform various configuration and administration tasks.
Table of Contents (16 chapters)
DNS in Action
About the Authors
Country Codes and RIRs

Chapter 10. DNS and Firewall

A firewall separates the company internal network (intranet) from the Internet. This enables intranet clients to gain information from the Internet, while preventing any aggressors on the Internet from attacking the computers of the internal network.

Let us say that a company has been assigned the domain. It will want to use this domain for both the Internet and its intranet. The domain in the Internet will most likely contain only a few records such as, and a few other records (MX records for pointing at, etc.). The domain on the intranet can contain, on the other hand, tens, hundreds, or even thousands of computers.

To put this differently, there will be two domains, with each of them containing different records, but the problem is that they both will have the same name. There cannot be two domains of the same name on the Internet. But both...