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DNS

WHAT IS IT ?

  • DNS translates the human-friendly domain names into the IP addresses that computers need to communicate with one another.

  • Without a DNS to resolve a domain name or the proper rights, users would have to know the IP address of each of the web pages or computers you wanted to access.

  • To promote efficiency, servers can cache the answers they receive for a set amount of time.

  • This allows them to respond more quickly the next time a request for the same lookup comes in. 

  • The domain name system (DNS) is the way that internet domain names are located and translated into internet protocol (IP) addresses. 

DNS

    Domain Name System 

or Domain Name Service

192.168.1.7

DNS Server

Requesting IP: googe.com

Response: 139.130.4.5

googe.com

Requesting google.com page

Response:

Internet

Google Web Server

DNS is an Internet or network server that helps to point domain names or hostnames to their associated IP address.

DNS WORKING

  • When you type a domain name (eg. oracle.com) into your web browser and computer determine if one of them already has the domain's related IP address in their memory.

  • If it is a domain that you have recently visited, can display the website in a split second.

  • If the domain is not found in local memory, your computer takes the search out to the Internet where it asks, or queries, a series of DNS servers, if they have the domain name in their memory or a database.

  • The first DNS server that receives the query checks its memory for the domain name.

  • As soon as the domain name is found on a DNS server, that server returns the domain name and its IP address to the requesting DNS server and on, until it arrives back at your computer.

oracle.com.

Resolving Name Server

Root Name Server

oracle.com.

CCTDL Server

.in

.us

.uk

etc

.com

.org

.edu

etc

TLD Name Server

(Top-level domain)

oracle.com.

abc

googe

oracle

Authoritative Name Server

oracle.com.

Returns ip 137.254.120.50

plus

doc     ....

map

developer

Subdomain

  • When a user wants to visit Computer Hope, they can type "https://www.abc.com" into the address bar of their browser.

  • Every website have a "." combined with and forword to the DNS server.

  • Root Name Server works with to find TLDand CCTLC name servers.

  • There are different name server works to find the ip address.

  • Once that domain name has been entered, it is looked up on a Domain Name System where it is translated into an IP address that is more easily interpreted by a computer.

  • Using that IP address, your computer can then locate the Computer Hope web page and forward that information to your browser.

  • Above is a visual example of how DNS works.

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