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

2.1 Resource Records

Information on domain names and their IP addresses, as well as all the other information distributed via DNS is stored in the memory of name servers as Resource Records (RR).

A name server (also referred to as a DNS server) loads data into its cache in several ways. Authoritative data are read from files on a disk or obtained via a zone transfer query from another authoritative servers. Nonauthoritative data are obtained by the server from other servers as it answers of individual DNS queries. Do not forget for special kind of nonauthoritative data - information about root name servers which are loaded locally from disk file.

If a DNS client needs to obtain information from a DNS, it requests RR from the DNS according to its requirements, i.e., a client can request from a domain server an A type RR with the IP addresses of the particular domain name. A client can be a resolver or a name server that cannot resolve the query on its own.

The structure of RR is prescribed...