MCSA/MCSE Self-Paced Training Kit (Exam 70-270): Installing ...

13-26 Chapter 13 Supporting TCP/IP
Lesson 2: Understanding the Domain Name System
The Domain Name System (DNS) is used on the Internet and on many private networks.
Private networks using Microsoft Active Directory directory service use DNS
extensively to resolve computer names and to locate computers within their local networks
and the Internet. In fact, networks based on Windows 2000 Server and Windows
Server 2003 use DNS as a primary means of locating resources in Active Directory
(which you will learn about in Chapter 14, “Overview of Active Directory Service”).
After this lesson, you will be able to
■ Explain how the domain namespace works.
■ Identify domain-naming guidelines.
■ Explain the purpose of zones.
■ Explain the purpose of name servers.
Estimated lesson time: 20 minutes
What Is the Domain Namespace?
The domain namespace is the naming scheme that provides the hierarchical structure
for the DNS database. Each node, referred to as a domain, represents a partition of the
DNS database.
The DNS database is indexed by name, so each domain must have a name. As you add
domains to the hierarchy, the name of the parent domain is added to its child domain
(called a subdomain). Consequently, a domain’s name identifies its position in the hierarchy.
For example, in Figure 13-8, the domain name sales.microsoft.com identifies the
sales domain as a subdomain of the microsoft.com domain and microsoft as a subdomain
of the com domain.
The hierarchical structure of the domain namespace consists of a root domain, toplevel
domains, second-level domains, and host names.
Note The term domain, in the context of DNS, does not correlate precisely to the term as
used on the Active Directory network. A Windows domain is a grouping of computers and
devices that are administered as a unit.