Lesson 5: Domain Name System pdf

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Lesson 5: Domain Name System

DNS is a distributed database used in TCP/IP networks to translate computer names (host

names) to IP addresses. This lesson introduces you to DNS and name resolution. It also

discusses the skills necessary and provides information to install and configure the DNS

service.

Introduction to DNS

DNS is most commonly associated with the Internet. However, private networks use

DNS extensively to resolve computer host names and to locate computers within their

local networks and the Internet. DNS name resolution is different than the name

resolution provided by WINS. WINS resolves NetBIOS names to IP addresses, while

DNS resolves IP host names to IP addresses. IP host names resolved using DNS or other

means, provide the following benefits:

• IP host names are user-friendly, which means they are easier to remember than IP

addresses.

• IP host names remain more constant than IP addresses. An IP address for a server

can change, but the server name remains the same.

• IP host names allow users to connect to local servers by using the same naming

convention as the Internet.

Domain Namespace

Domain namespace is the naming scheme that provides the hierarchical structure for the

DNS database. Each node represents a partition of the DNS database. These nodes are

referred to as domains.

The DNS database is indexed by name; therefore, each domain must have a name. As

you add domains to the hierarchy, the name of the parent domain is appended to its child

domain (called a subdomain). Consequently, a domain's name identifies its position in the

hierarchy. For example, in Figure 9.10 the domain name sales.microsoft.com identifies

the sales domain as a subdomain of the microsoft domain and microsoft as a subdomain

of the com domain.