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

10.1 Shared DNS for Internet and Intranet

The easiest solution is sharing a DNS database between the Internet and intranet. This might be unsuitable for two reasons:

  • Translations of computers with nonroutable addresses (net 10/8, 172.16/12, or 192.168/16) are published on the Internet.

  • Information concerning the company structure is published (IP addresses of intranet computers). This information is usually confidential.

The most significant question when configuring DNS on the firewall is whether or not all Internet names should be translated on the intranet, and whether the intranet clients should be enabled to translate the names of the domain that are located on the intranet only.

10.1.1 The Whole Internet is Translated on the Intranet

If the whole Internet is translated on the intranet, then the intranet must also route IP addresses of the whole Internet. This has some negative effects as well:

  1. 1. The routing of the intranet must be ready for this, i.e., all IP addresses that...