Domain Name System

Explanation of DNS and internet.


Domain Name System - Name Server's

To explain in detail, we will assume that you are typing a website say in a browser. The following process takes place one by one.
a) Your PC contacts your ISP name server (e.g: NS-A) and request for any detail of the ip-Address of
Name Server
Every ISP and servers (hosting company) will have a server called name server where the ip address to domain name mapping is done.

b) NS-A gets in touch with the root servers and gets the address of the .com TLD server. There are totally around 13 root server located in different parts of the world. They give the information of TLD Name servers.
c) NS-B is the name server that has ip-address info for
d) Each TLDs (e.g: .com, .net, .org,..) servers have the information of all the lower hierarchy Name Servers (e.g NS-B). Thus the .com TLD server fetches the's ip-address from the NS-B to NS-A.
e) Now the request data (called as packet) for required details is send from your PC with the from ip and destination ip ( thro internet.
f) The data travels thro the internet network and reaches the destination ip.
g) There the data if verified and it sends back the details with its ip-address as source and our PC's ip-address as destination
h) The data travels thro the dense internet network and reaches you.
Once the ip of a destination website is fetched it will remain in a cache for some period of time. So when ever the name server details is required it will be searched first in cache. Name Server will be requested for details only in the cache does not contain the required details.

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