11.6.2.2 describe the purpose and organization of a domain name system (DNS)

DNS

The Domain Name System (DNS) is a hierarchical and decentralized naming system for computers, services, or other resources connected to the Internet or a private network.

It associates various information with domain names assigned to each of the participating entities.

It is most commonly used to obtain an IP address by hostname, obtain mail routing information and / or service nodes for protocols in a domain.

Domain name is part of the URL for a resource on the internet. 

For example, nis.edu.kz, bzfar.org, vk.com

In nis.edu.kz:

kz - top level domain name

edu - second level domain name

nis - third level domain name or subdomen

Top level domain name

A top level domain (TLD) is the portion of the domain that appears on the right side of the domain name after the dot, such as com, org, or net.

TLDs are divided into two types:

DNS server

DNS server is an internet service that translates website domain names into IP addresses.

All websites have equivalent IP addresses.

Why a company use a domain name instead of an IP Address for their website?

• Domain names are easier to remember
• You can change the IP address without the user noticing
• You can host several web sites on one IP address

Questions:

Exercises:

Ex. 1

Exam questions: