"Imagine you’re asking your friend for their home address, and they reply with, 'I live at Latitude: 19.9248994° and Longitude: 1.24248457°.' You’re left scratching your head, wondering what on earth those numbers mean. You can’t possibly remember those coordinates, let alone find the house! Now, let’s take another example: you want to call your friend, but instead of memorizing their phone number, you’ve saved it under their name in your phone’s contact list. The name is mapped to their phone number. This is precisely how DNS works—mapping user-friendly domain names to computer-friendly IP addresses."
If you have read my previous article I have discussed about the IP address, if have not gone through, I will explain you about the IP address in brief.
IP address is a unique identifier for each device in the network, just like a person contact number, the IP address is given by the Internet Service Provider, well the person cannot remember the number so it is mapped to the names called Domain Names.
DNS - Domain Name System
The DNS turns domain names to IP-address, through which browsers get data from that particular server. Every DNS that exists are connected to the internet, there are total 13 Root DNS servers
| Host Name | IP Address | Operator |
| a.root-servers.net | 198.41.0.4, 2001:503:ba3e::2:30 | Verisign, Inc. |
| b.root-servers.net | 170.247.170.2, 2801:1b8:10::b | University of Southern California, |
| Information Sciences Institute | ||
| c.root-servers.net | 192.33.4.12, 2001:500:2::c | Cogent Communications |
| d.root-servers.net | 199.7.91.13, 2001:500:2d::d | University of Maryland |
| e.root-servers.net | 192.203.230.10, 2001:500:a8::e | NASA (Ames Research Center) |
| f.root-servers.net | 192.5.5.241, 2001:500:2f::f | Internet Systems Consortium, Inc. |
| g.root-servers.net | 192.112.36.4, 2001:500:12::d0d | US Department of Defense (NIC) |
| h.root-servers.net | 198.97.190.53, 2001:500:1::53 | US Army (Research Lab) |
| j.root-servers.net | 192.58.128.30, 2001:503:c27::2:30 | Netnod |
| k.root-servers.net | 193.0.14.129, 2001:7fd::1 | RIPE NCC |
| l.root-servers.net | 199.7.83.42, 2001:500:9f::42 | ICANN |
| m.root-servers.net | 202.12.27.33, 2001:dc3::35 | WIDE Project |
Components of DNS server
Before understanding the working of DNS server understand the components and hierarchy of the DNS server as it sets a strong foundation for understanding the working of DNS server
Root DNS Server:
It is the starting point of the DNS query resolution.
It does not store the IP address of the domain names it redirects to appropriate TLD server.
There are 13 logical root servers as seen in the above list from A to M.
Here it checks the extension i.e
.comor.inlike this, based on this it will be sent to that particular TLD
TLD (Top Level Domain) Server:
Even the top level domain do not store the IP address.
It stores the Authoritative Name Server Records (NS records)
NS records connect a domain name to its IP address by telling the internet where to find the domain's DNS records.
Based on the query it redirects to authoritative server.
Authoritative Server:
The final source for the DNS records of a domain.
Stores DNS records like A (IP address), CNAME, MX, NS, and TXT for the domain.
Example: ns1.godaddy.com, ns2.cloudflare.com.
Recursive DNS Resolver:
Acts as the query handler or middleman between the client and other DNS servers.
Receives DNS queries from clients (e.g., browsers).
If not found, queries other DNS servers (Root, TLD, and Authoritative) until it resolves the query.
Understanding the working with real life analogy.
You (Browser): You decide to visit "Sumukha Sureban's Office" and ask around for directions.
Local Area Inquiry (Browser Cache): You check with people nearby (your local memory or browser cache) if anyone knows the address of "Sumukha Sureban's Office." If someone remembers, you go there immediately.
City Help Desk (Recursive Resolver): If no one locally knows the address, you go to the city's main help desk (recursive resolver) to ask for directions.
Country's Directory Office (Root Server): The help desk doesn't directly know the location but tells you to check with the country's directory office (root server) to narrow down the region.
Regional Office Directory (TLD Server): The directory office identifies the category (like a
.comfor businesses or.infor Indian offices). Since you're looking for "sumukhasureban.com," they direct you to the business directory office (TLD server for.com).Specific Building Directory (Authoritative Server): The business directory gives you the exact building and floor where "Sumukha Sureban's Office" is located. This corresponds to the authoritative name server that holds the exact IP address for "sumukhasureban.com."
Directions Back (Response): The help desk gets this address and tells you where to go. Finally, you arrive at Sumukha Sureban's Office.
Explore:
Types of DNS records.