This content originally appeared on DEV Community and was authored by JAYA SRI J
first let see as flow:
user----> DNS query initialization----> sub resolver [local machine]
example:
www.wikipedia.org.
here last [.] represent root
org represents TLD [Top level domain]
Wikipedia represents SLD [secondary level domain]
www represents Zone file
root [name server]
/ | \
/ | \
/ | \
.org .com .in
[Name server]
/
/
/
Wikipedia [name server]
/
/
/
www ------> IP
zone file :
A -----> IPV4
AAAA----> IPV6
mx-------> mail
When your browser needs to resolve a domain (like www.wikipedia.org.), it doesn’t directly go to root servers first.
It usually goes to a DNS resolver provided by your ISP (Internet Service Provider).
Here’s the real-world flow:
- You Type a Website www.wikipedia.org.
- Browser Checks Cache
If not found → continue
- Request Goes to ISP DNS Resolver
Your device sends the request to:
Your ISP’s DNS server
Example:
Airtel DNS
Jio DNS
This server is called a recursive resolver
- ISP Resolver Checks Cache If it already knows → returns IP immediately If not → it starts querying:
- ISP Contacts Root Server org[.]
“Where is www.wikipedia.org.?”
- ISP Contacts TLD Server org.
“Where is www.wikipedia.org.?”
7.next it goes to SLD here it has the Ip address
where is www.wikipedia.org.
- zone file is www it has IPV4 :A IPV6:AAAA MX: MAIL
This content originally appeared on DEV Community and was authored by JAYA SRI J
JAYA SRI J | Sciencx (2026-03-25T15:29:26+00:00) how DNS happening. Retrieved from https://www.scien.cx/2026/03/25/how-dns-happening/
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