Introduction: How does a browser know where a website lives?
Think about this for a second.
You open your browser, type google.com, and press Enter. Within milliseconds, Google’s homepage appears on your screen.
But here’s the interesting part:
your browser has no idea what google.com actually is.
Computers don’t understand names like google.com, facebook.com, or amazon.in. They only understand numbers.
So the real question is:
How does your browser convert a human-friendly website name into the correct server on the internet?
That’s exactly where DNS comes in.
DNS works quietly in the background every time you visit a website, helping your browser figure out where that website actually lives on the internet without you ever noticing.
What is DNS? (The Phonebook of the Internet)
DNS stands for Domain Name System.
In simple words, DNS is the system that helps computers find websites using names instead of numbers.
Humans like names. Computers like numbers.
When you type a website name like google.com, your browser cannot understand it directly. Computers do not know what google means. What they understand is something called an IP address, which looks like a set of numbers.
This is where DNS helps.
You can think of DNS as the phonebook of the internet.
In a phonebook:
On the internet:
Once the browser gets the correct IP address, it knows exactly where to send the request, and the website loads on your screen.
All of this happens in the background, usually in a fraction of a second. That’s why browsing feels instant, even though many steps are involved behind the scenes.
The important thing to remember is this:
DNS does not store websites.
DNS only helps your browser find where a website is located.
Why Are DNS Records Needed?
So far, we’ve learned that DNS helps convert a website name into an IP address. But here’s an important question:
Is one piece of information enough for a domain?
The answer is no.
A single domain name needs to store different types of information, not just where the website is hosted.
Think of a domain like a house.
A house doesn’t have just one detail. It has:
An address that tells people where it is
Someone responsible for managing it
A mailbox for receiving letters
Extra instructions, like delivery notes or security codes
In the same way, a domain needs multiple kinds of information, such as:
Where the website is located
Who is responsible for the domain
Where emails for the domain should be delivered
Extra data used for verification and security
Storing all this information in a single place would be confusing. So DNS uses different types of records, each designed to solve one specific problem.
Each DNS record has a clear role:
One record handles website location
Another handles email routing
Another defines authority
Another stores additional instructions
This separation keeps DNS organized, flexible, and easy to manage.
In the next sections, we’ll look at these DNS records one by one, starting with the record that answers an important question:
Who is responsible for this domain?
NS Record: Who Is Responsible for a Domain?
Before DNS can find a website or send emails, it must answer one question:
Which DNS servers control this domain?
That’s the job of an NS (Name Server) record.
An NS record tells the internet where to ask for DNS information about a domain. It points to the DNS provider that manages all other records for that domain.
Think of it like this: Before asking details about a house, you first ask who is in charge of it.
NS records do not:
Point to a website
Store IP addresses
Handle emails
They only define authority.
If NS records are incorrect, the domain will not work properly — even if all other DNS records are correct.
In short: NS records decide who controls the domain’s DNS.
A Record: Domain Name → IPv4 Address
An A record connects a domain name to a server.
It tells DNS:
“When someone visits this domain, send them to this IPv4 address.”
An IPv4 address is a numeric address like 192.168.1.1 that identifies a server on the internet.
So when you type a website name in your browser:
DNS looks up the A record
It finds the IP address
The browser sends the request to that server
Think of the A record as the exact house address for a website.
Practical Example
Domain Name: rithbanerjee.site
Record Type: A
Value: 203.0.113.42
TTL: 3600 (seconds)
When you visit rithbanerjee.site, DNS returns the IP address 203.0.113.42, and your browser connects to the server at that address.
AAAA Record: Domain Name → IPv6 Address
An AAAA record does the same job as an A record, but for IPv6 addresses.
While A records point to IPv4 addresses, AAAA records point to IPv6 addresses, which look longer and are designed to support many more devices on the internet.
In simple terms:
If a website supports IPv6, DNS can return the IPv6 address using an AAAA record.
CNAME Record: One Domain Name Pointing to Another
A CNAME record is used when one domain name should point to another domain name, instead of an IP address.
CNAME stands for Canonical Name.
In simple terms, it tells DNS:
“This domain is just another name for that domain.”
For example:
DNS first follows the CNAME, and then looks up the final A or AAAA record.
MX Record: How Emails Find Your Mail Server
An MX record tells the internet where emails for a domain should be delivered.
MX stands for Mail Exchange.
When someone sends an email to you@rithbanerjee.site, the email server:
Looks up the MX record for rithbanerjee.site
Finds the mail server responsible for receiving emails
Delivers the email there
MX records ensure that emails go to the correct mail server, not the web server.
Practical Example
Domain Name: rithbanerjee.site
Record Type: MX
Priority: 10
Value: mail.hostingprovider.com
TTL: 3600
Secondary (Backup):
Record Type: MX
Priority: 20
Value: mail2.hostingprovider.com
Emails sent to user@rithbanerjee.site go to mail.hostingprovider.com (priority 10). If that server is down, they go to mail2.hostingprovider.com (priority 20). Lower priority numbers are tried first.
A TXT record is used to store extra text-based information about a domain.
TXT records don’t control websites or emails directly. Instead, they are mainly used for verification and security purposes.
They tell other services:
“This domain is really owned or controlled by me.”
Practical Examples
Domain Ownership Verification:
Domain Name: rithbanerjee.site
Record Type: TXT
Value: google-site-verification=abc123xyz789
Email Security (SPF Record):
Domain Name: rithbanerjee.site
Record Type: TXT
Value: v=spf1 include:mail.hostingprovider.com ~all
This tells email servers: "Only emails from mail.hostingprovider.com are legitimate for this domain."
DKIM (Email Authentication):
Domain Name: default._domainkey.rithbanerjee.site
Record Type: TXT
Value: v=DKIM1; p=MIGfMA0B... (public key)
How All DNS Records Work Together for One Website
A real website does not use just one DNS record. It uses multiple records, each handling a different responsibility.
Understanding DNS Resolution: The Complete Journey
When you type rithbanerjee.site in your browser, here's what happens behind the scenes:
This hierarchical system ensures DNS requests are handled efficiently and reliably.
Complete Example: All Records for One Domain
Here's what a real DNS setup looks like for rithbanerjee.site:
┌─────────────────────────────────────────────────┐
│ rithbanerjee.site │
└─────────────────────────────────────────────────┘
│
├─ NS Record
│ Value: ns1.example-dns.com
│ (Who controls this domain)
│
├─ A Record
│ Value: 203.0.113.42
│ (Website IP address)
│
├─ AAAA Record
│ Value: 2001:db8::1
│ (IPv6 website address)
│
├─ CNAME Record (www)
│ www.rithbanerjee.site → rithbanerjee.site
│
├─ MX Record (Primary)
│ Priority: 10
│ Value: mail.hostingprovider.com
│ (Primary email server)
│
├─ MX Record (Secondary)
│ Priority: 20
│ Value: mail2.hostingprovider.com
│ (Backup email server)
│
└─ TXT Records
SPF: v=spf1 include:mail.hostingprovider.com ~all
DKIM: v=DKIM1; p=MIGfMA0B...
Verification: google-site-verification=abc123xyz789
Step 1: NS Records — Who Controls the Domain
When someone looks up rithbanerjee.site, DNS first checks the NS records.
These records answer:
“Which DNS servers are responsible for this domain?”
Once the correct name servers are found, DNS knows where to ask for further details.
Step 2: A / AAAA Records — Where the Website Lives
Next, DNS looks for A or AAAA records.
These records answer:
“What is the IP address of this website?”
Using this information, the browser connects to the web server and loads the website.
Step 3: CNAME Records — Aliases for the Domain
If a domain like www.rithbanerjee.site is used, DNS may follow a CNAME record.
This tells DNS:
“This name is just an alias. Look somewhere else.”
DNS follows the CNAME until it reaches an A or AAAA record.
Step 4: MX Records — Handling Emails
When someone sends an email to user@rithbanerjee.site, DNS checks the MX records.
These records answer:
“Which mail server should receive emails for this domain?”
Emails are delivered to the mail server, not the web server.
Step 5: TXT Records — Verification and Security
TXT records provide extra information about the domain.
They are used for:
Domain ownership verification
Email security rules (SPF, DKIM, DMARC)
Connecting external services
They help other systems trust your domain.
The Big Picture
Each DNS record has one clear job:
Together, they allow a single domain to handle websites, emails, and services smoothly.
DNS works best because each record solves one specific problem.
Common beginner confusions (A vs CNAME, NS vs MX)
A Record vs CNAME
Easy rule: A = name → number CNAME = name → name
NS Record vs MX Record
Easy rule: NS = DNS control MX = Email delivery
Each DNS record has one job. Problems happen only when those jobs get mixed up.
Wrap-up: DNS in One Simple Picture
At a high level, DNS is just a system that helps the internet answer simple questions about a domain.
Who controls this domain? → NS
Where is the website hosted? → A / AAAA
Is this domain an alias? → CNAME
Where should emails go? → MX
How can services verify this domain? → TXT
Each record has one clear job. Together, they allow a single domain to run a website, send emails, and connect with other services smoothly.
If you remember only one thing, remember this:
DNS is not complicated — it’s just organized.
One Simple DNS Picture (Mermaid Diagram)
You don’t need to memorize DNS records. Once you understand what problem each record solves, DNS starts to feel logical instead of confusing.
