How does DNS work step by step

 
Client enters a domain name (www.domainname.com) into his browser
The browser contacts the Client's ISP for the IP address of the domain name
The ISP first tries to answer by itself using "cached" data.
If the answer is found it is returned. Since the ISP isn't in charge of the DNS, and is just acting as a "dns relay", the answer is marked "non-authoritative"
If the answer isn't found, or it's too old (past the TTL), then the ISP DNS contacts the nameservers for the domain directly for the answer.
If the nameservers are not known, the ISP's looks for the information at the 'root servers', or 'registry servers'. For com/net/org, these start with a.gtld-servers.net.
NOTE: The 'whois' information is never used for DNS, and is often misleading and inaccurate 

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1 comment:

Briyani Missisipi said...

Good information.I would like to share some points about DNS in simple words.

DNS means Domain Name System which helps to transfer IP address to Domain name and Domain name to IP addresses.It plays vital role in Internet technology.For Example,if you provide domain name like Google.com it convert the domain name into particular IP address.If you provide the IP address like 74.125.239.9 the DNS search for the particular website and display on your browser.DNS consist of many resource records.Some of them are A record,CNAME record,DNAME record etc..
You can check website DNS query from WhoisXY.com .