The Domain Name System (DNS) converts human-readable domain names (for example, www.amazon.com) into computer-understandable IP addresses (for instance, 192.0. 2.44).
In this article, we will look more into DNS according to the GATE Syllabus for (Computer Science Engineering) CSE. We will read ahead to find out more about it.
Table of Contents
What is DNS?
An application layer protocol specifies how messages are passed between application processes that are executing on various systems.
- The domain name system is known as DNS.
- A directory service called DNS establishes a connection between a host’s name and address on a network.
- The functionality of the internet depends on DNS.
- Every node in a tree contains a domain name, which is a string of symbols separated by dots.
- A service called DNS converts domain names into IP addresses. This enables network users to locate other hosts by using friendly names rather than their memory of IP addresses.
- For instance, if the IP address of the FTP site at EduSoft was 132.147.165.50, most users would navigate to it by entering ftp.EduSoft.com. As a result, domain names are more trustworthy than IP addresses.
TCP/IP protocol DNS is used on several platforms. Country domains, generic domains, and inverse domains are the three divisions of the domain name space.
Generic Domains
- It characterises the registered hosts based on their typical activity.
- The domain name, which serves as an index to the DNS database, is defined by each node of a given tree.
- It employs three-character designations that specify the sort of organisation.
| Description | Label |
| Airlines and aerospace companies | aero |
| Businesses or firms | biz |
| Commercial organisations | com |
| Cooperative business organisations | coop |
| Educational institutions | edu |
| Government institutions | gov |
| Information service providers | info |
| International organisations | int |
| Military groups | mil |
| Museum & other nonprofit organisations | museum |
| Personal names | name |
| Network Support centres | net |
| Nonprofit organisations | org |
| Professional individual organisations | pro |
Country Domains
The format of a country domain is the same as a generic domain, but two-character country abbreviations are used in place of three-character organisational abbreviations (for example, us for the United States).
Inverse Domains
An address is mapped to a name using the inverse domain when a client requests the server and only approved clients’ files are present on the server. The DNS server receives a request from the client asking for the mapping of an address to a name in order to identify whether the client is on the approved list or not.
Working of DNS
- It is a network communication protocol of the client/server type in which the client sends requests to the DNS server. On the other hand, the server sends responses to these clients.
- The client requests consist of a name that gets converted into IP addresses called a forward DNS lookup. The requests that contain an IP address get converted into a name called the reverse DNS lookups.
- In order to keep the names of all hosts that are accessible via the internet, DNS creates a distributed database.
- When a client, such as a web browser, submits a request with a hostname, a piece of software, such as a DNS resolver, submits a request to the DNS server to acquire the IP address of the hostname. The request is forwarded to another DNS server if the DNS server does not have the IP address linked to a hostname. If the resolver receives an IP address, it completes the request over the internet protocol.
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