Book Image

Managing Mission - Critical Domains and DNS

By : Mark E.Jeftovic
Book Image

Managing Mission - Critical Domains and DNS

By: Mark E.Jeftovic

Overview of this book

Managing your organization's naming architecture and mitigating risks within complex naming environments is very important. This book will go beyond looking at “how to run a name server” or “how to DNSSEC sign a domain”, Managing Mission Critical Domains & DNS looks across the entire spectrum of naming; from external factors that exert influence on your domains to all the internal factors to consider when operating your DNS. The readers are taken on a comprehensive guided tour through the world of naming: from understanding the role of registrars and how they interact with registries, to what exactly is it that ICANN does anyway? Once the prerequisite knowledge of the domain name ecosystem is acquired, the readers are taken through all aspects of DNS operations. Whether your organization operates its own nameservers or utilizes an outsourced vendor, or both, we examine the complex web of interlocking factors that must be taken into account but are too frequently overlooked. By the end of this book, our readers will have an end to end to understanding of all the aspects covered in DNS name servers.
Table of Contents (17 chapters)
7
Types and Uses of Common Resource Records

When does DNS use TCP instead of UDP?

Most of the time, DNS happens over UDP. It's lightweight and faster than TCP. There have been trade-offs as a result of the design decision. It's easier to spoof UDP packets, so you have to worry about things like cache poisoning or DDoS attacks involving forged packet headers.

But nameservers still need to be available on TCP as well as UDP. The following will explain why.

Zone transfers happen over TCP

The AXFR and IXFR methods of transferring updated zone data from the master to its secondaries occur over TCP.

In some cases, when a slave queries the master to check whether an update is required, it may happen over TCP (for example, NSD nameservers do this).

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