What is DNS? and how does DNS work?
Domain Name?
A Domain Name is an easy-to-remember and unique name assigned to a website. For example wix.com, ananthaexpeditions.com, google.com, Facebook.com, oracle.com.
What is a Domain Name Registrar?
A Domain Name Registrar is a business that handles the reservation of domain names as well as the assignment of IP addresses for those Domain Names. For example, Google's primary domain is google.com. Google also owns and operates a number of other domains such as YouTube.com, blogger.com, and googlemaps.com.
Google's IP address is not publicly available. This is because Google uses a variety of techniques to protect its infrastructure from hacking and attacks. However, if you use a public DNS server to look at the IP address of google.com, you will see a list of IP addresses associated with that domain name.
>> nslookup google.com Server: fe80::389c:b2ff:fe59:b664%4 Address: fe80::389c:b2ff:fe59:b664%4#53
Non-authoritative answer: Name: google.com Address: 142.250.188.238 |
It is important to note that registrars do not maintain and manage domain names, that part is done by the domain registry.
So, what is the difference between a registrar and a registry?
Registries are the organizations that manage top-level domains (TLDs) such as '.com' and '.net'. In simple terms, a TLD is everything that follows the final dot of a domain name. For Example, in the domain name 'google.com', '.com' is the TLD. Some other popular TLDs are '.org', '.in', '.ca', '.edu', '.gov', and '.uk'.
The ICANN (Internet Corporation for Assigned Names and Numbers) has authority over all the TLDs used on the Internet and delegates the responsibility of these TLDs to various companies. For Example, a U.S. company called Verisign operates all '.com' and '.net' TLDs. Every TLD will tell you something about the domain that precedes it. For Example,
'.in' is for the domains from India.
'.ca' is for domains from Canada.
'.com' is for Commercial Businesses.
'.gov' is for U.S. government entities.
A registrar is like a dealership for domain names, and the registry is like the manufacturer.
For Example, Apple takes the ownership of design and manufacturing of iPhones and other Apple products, while AT&T, T-Mobile, Verizon, and others take the dealership of selling iPhones.
DNS?
Domain Name System is the phonebook of the Internet.
How does DNS work?
The process of DNS resolution involves converting a hostname such as ananthaexpeditions.com into a computer-friendly unique IP address (such as 198.168.1.1). Each device on the Internet has a unique IP address associated with it, and by this IP address, that particular device gets identified. For example, If you want to deliver mail to a person, that person should be associated with a physical street address(s).
>> nslookup ananthaexpeditions.com Server: fe80::389c:b2ff:fe59:b664%4 Address: fe80::389c:b2ff:fe59:b664%4#53 Non-authoritative answer: Name: ananthaexpeditions.com Address: 185.230.63.171 Name: ananthaexpeditions.com Address: 185.230.63.186 Name: ananthaexpeditions.com Address: 185.230.63.107 |
Behind the scenes
There are 4 DNS Servers involved in loading the webpage:
DNS Recursive Resolver.
DNS Root Nameserver.
DNS TLD Nameserver.
Authoritative Nameserver.
Difference between an Authoritative DNS server and a recursive DNS resolver
In simple terms, both Authoritative DNS servers and Recursive DNS resolvers are two key components of the DNS Name.
The Authoritative DNS Server is like the phone book of the DNS Names. It has all the Domain Names and their IP addresses. This is like the final destination in the DNS lookup process. When asked about a domain name, the Authoritative DNS server looks up the data from its database and provides accurate details. It doesn't send or ask information to any other servers but gets the details from itself.
The Recursive DNS resolver is like a detective, which takes the input from the end user and goes on a quest to find the IP address. First, it looks into its own database and cache to see if it can find relevant information. If it cannot be located, then it starts its research beginning from the root servers, then goes a level up to the top-level domains (TLDs), and at the end to the Authoritative DNS servers. Once the information is acquired, it will be returned to the user, at the same time stored in its cache for a certain time called TTL (Time-To-Live).
Steps in a DNS lookup
A user launches the browser (Google Chrome, Microsoft Edge, Safari, Firefox) and types "google.com" in the address bar, and presses Enter.
The query travels into the Internet and is received by the Recursive DNS resolver.
The resolver queries a DNS root name server, where the root nameserver is (.).
The root name server then responds to the Recursive DNS resolver with the address of a Top Level Domain Name server (TLD) such as '.com' or '.net'. In this scenario, it is '.com' TLD.
The Recursive DNS resolver then makes a request to the .com TLD.
The TLD name server then responds to the resolver with the IP address of the domain's nameserver 'google.com'.
The recursive DNS resolver sends a query to the domain's nameserver.
The IP address for google.com is then returned to the resolver from the domain's nameserver.
The DNS resolver then responds to the web browser with the IP address for google.com.
Once the above steps are done, the browser makes an HTTPS connection to the returned IP address.
The server at the IP address (google) returns the webpage to be rendered by the browser.
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