Services Offered By a DNS Server

The DNS server is a vital component in a network. It is the most popular name resolution service on the Internet. A few functions of a DNS server are given in the following list:

• Provides a mechanism for resolving host names into Internet Protocol (IP) addresses. This process is known as forward lookup.
• Provides a mechanism to find host names from IP addresses. This is known as a reverse lookup.
• Provides Internet directory-like lookup capabilities to retrieve information concerning other DNS Name Servers, Canonical Names, Mail Exchangers, and so on.
• Allows machines to be logically grouped by domains names, and therefore, lead to efficient searching.
• Organizes named machines into efficient hierarchies.
• Is distributed by nature, which increases its robustness and reliability.

Components of DNS

The DNS implementation in a network has three major components: database, client, and server. These components are discussed in the following list:

• Database. The database contains the DNS tree and the Resource Records (RR). RR specifies the domain name. The database is distributed in nature and comprises the Domain Name Space, which is basically the DNS tree, and the Resource Records (RRs). RR defines the domain names within the Domain Name Space.
• Client. The client in the DNS contains functions or software routines, which request information from the Domain Name Space on behalf of an application. The clients in the DNS are also known as resolvers because they group functions to a resolver library. The resolver library sends query to the name server, accepts answers, and sends it back to the specific application. The client contains methods for gaining information from the DNS. The client is used by the applications.
• Server. The server in the DNS is called a Name Server. These servers manage portions of the Domain Name Space and assist clients in finding information within the DNS tree. In addition, servers can be used as a delegation point to identify other name servers that have authority over subdomains within a given domain.