Every time you open a website, you usually type a simple name such as google.com, youtube.com, or mindfultomorrow.com into your browser. But computers don’t communicate with websites using these easy-to-remember names. They use IP addresses.
So how does your browser know which IP address belongs to a particular website?
That’s where DNS (Domain Name System) comes in.
DNS works like the internet’s phonebook. It translates human-friendly domain names into IP addresses that computers and network devices can understand.
In this guide, we’ll explain what DNS is, how DNS works step by step, what happens when you visit a website, different types of DNS servers, DNS records, DNS caching, and why DNS is so important for the internet.
What Is DNS?
DNS stands for Domain Name System. It is a distributed system used to translate domain names into IP addresses and provide other information about internet domains.
For example, when you enter:
www.example.com
your device needs to find the IP address associated with that domain before it can establish a connection to the appropriate server.
A simplified example is:
Domain name: example.com
IP address: 93.184.216.34
Instead of remembering a long sequence of numbers, you can simply remember the domain name.
Why Do We Need DNS?
Without DNS, you would often need to access websites using IP addresses.
Imagine having to remember:
142.250.x.x
instead of:
google.com
That would make using the internet much more difficult.
DNS makes the internet easier to use by allowing people to access websites using human-readable domain names.
How Does DNS Work?
When you enter a website address into your browser, several DNS-related steps can happen before the website loads.
A simplified process looks like this:
You enter a domain → DNS lookup → IP address found → Browser connects to server → Website loads
For example:
You type: mindfultomorrow.com
DNS finds: The appropriate IP address
Browser connects: To the web server
Website loads: In your browser
The actual DNS process can involve multiple servers and caches.
Step-by-Step DNS Lookup
Let’s look at what can happen when you visit a website.
Step 1: You enter a domain name
You type a website address into your browser.
Step 2: Your device checks its local DNS information
Your operating system or browser may already have a cached DNS result.
Step 3: Your DNS resolver is contacted
If the answer isn’t already cached, your device sends a DNS query to a DNS resolver.
Step 4: The resolver searches for the answer
If the resolver doesn’t already know the answer, it can query other DNS servers.
Step 5: The domain’s IP address is returned
The resolver receives the relevant DNS information.
Step 6: Your browser connects to the destination
Your browser can now use the returned IP address to connect to the website’s server.
This entire process can happen very quickly.
What Is a DNS Resolver?
A DNS resolver is a server that receives DNS queries from clients and finds the appropriate DNS information.
Your internet connection may automatically provide a DNS resolver through your ISP.
You can also configure your devices or router to use a different DNS service.
What Does a DNS Resolver Do?
A resolver may:
- Receive your DNS query
- Check its cache
- Query authoritative DNS servers when necessary
- Follow the DNS hierarchy
- Return the requested DNS information
- Cache the result for future requests
The resolver essentially acts as the middleman between your device and the DNS system.
What Is a Recursive DNS Resolver?
A recursive resolver is responsible for finding the answer to a DNS query on behalf of the client.
For example, your computer might ask:
“What is the IP address of example.com?”
The recursive resolver may then perform the necessary DNS queries to find the answer.
If it already has a valid cached answer, it may respond immediately without contacting other DNS servers.
What Is a Root DNS Server?
At the top of the DNS hierarchy are the root DNS servers.
There are 13 named root server identities, operated by multiple organizations, with many physical and network instances distributed around the world.
The root system doesn’t normally provide the final IP address for a website.
Instead, it helps direct DNS resolvers toward the appropriate Top-Level Domain (TLD) name servers.
Example
Suppose you’re looking up:
example.com
The DNS hierarchy can be simplified as:
Root → .com TLD → example.com authoritative DNS server
The authoritative server can then provide the DNS record needed for the domain.
What Is a TLD DNS Server?
TLD stands for Top-Level Domain.
Examples include:
.com.org.net.edu.gov.bd.uk
TLD name servers help DNS resolvers find the authoritative name servers responsible for specific domains.
Example
For:
example.com
the .com TLD infrastructure can direct the resolver toward the authoritative DNS servers for example.com.
For:
example.bd
the .bd DNS infrastructure is involved instead.
What Is an Authoritative DNS Server?
An authoritative DNS server contains the official DNS records for a domain or DNS zone.
For example, a domain’s authoritative DNS servers may contain information such as:
- Website IP address
- Mail server
- Nameservers
- Verification records
- Other DNS information
When a resolver reaches the authoritative server, it can obtain the authoritative answer for the requested domain.
Why Is It Called “Authoritative”?
It’s called authoritative because the server is providing DNS information from the source responsible for that domain or zone.
For example, if a domain has authoritative nameservers configured with a DNS provider, those servers hold the DNS records that determine where services for that domain should point.
What Are DNS Records?
DNS records are pieces of information stored in DNS.
Different record types serve different purposes.
Some of the most common DNS records include:
- A
- AAAA
- CNAME
- MX
- TXT
- NS
- SOA
- PTR
A Record
An A record maps a domain name to an IPv4 address.
Example:
example.com → 203.0.113.10
This is commonly used to point a domain to a web server.
AAAA Record
An AAAA record maps a domain name to an IPv6 address.
Example:
example.com → 2001:db8::10
It serves a similar purpose to an A record but is used for IPv6.
CNAME Record
A CNAME (Canonical Name) record points one domain name to another domain name.
For example:
www.example.com → example.com
The destination name can then provide the appropriate A or AAAA record.
MX Record
An MX (Mail Exchange) record specifies which mail servers handle email for a domain.
For example:
example.com → mail.example.com
Mail systems use MX records to determine where email should be delivered.
TXT Record
A TXT record stores text information associated with a domain.
TXT records are commonly used for:
- Domain verification
- SPF information
- Email authentication
- Security-related configurations
- Service verification
NS Record
An NS (Name Server) record identifies the authoritative DNS servers for a domain or DNS zone.
For example:
example.com → ns1.example-dns.com
SOA Record
The SOA (Start of Authority) record contains important information about a DNS zone, including information related to the zone’s authoritative server and timing parameters.
What Is DNS Caching?
DNS caching means storing DNS information temporarily so it doesn’t need to be looked up from the beginning every time.
Caching can happen in several places.
For example:
- Web browser
- Operating system
- Home router
- ISP resolver
- Public DNS resolver
Why Is DNS Caching Useful?
Caching can make DNS lookups faster and reduce unnecessary DNS traffic.
Suppose you visit the same website repeatedly.
Instead of asking the DNS hierarchy for the IP address every time, your resolver may already have the answer cached.
It can then respond much faster.
What Is TTL in DNS?
TTL stands for Time To Live.
A DNS record’s TTL tells caching resolvers how long they can generally keep the record before they should obtain a fresh answer.
For example, if a DNS record has a TTL of:
3600 seconds
that’s 1 hour.
After the cached information becomes stale, the resolver can query DNS again.
Does DNS Change Immediately?
Not always.
This is why you might change a DNS record and find that some users still reach the old server for a while.
Caching and TTL values can affect how quickly DNS changes are observed across different networks.
What Happens When You Change Your Website’s IP Address?
Suppose your website currently points to:
203.0.113.10
You move the website to a new server:
198.51.100.20
You update the DNS record.
Some DNS resolvers may continue using the previous cached information until its TTL expires.
Eventually, resolvers obtain the updated record.
This process is commonly referred to as DNS propagation, although technically it is largely the result of caching and different DNS components refreshing their information at different times.
What Is DNS Propagation?
DNS propagation describes the period during which DNS changes become visible through different DNS resolvers and networks.
For example, after changing an A record, one user might reach the new server while another user temporarily reaches the old server.
How Long Does DNS Propagation Take?
There is no universal fixed time.
It depends on factors such as:
- Previous TTL
- Resolver caching
- DNS configuration
- Provider behavior
- Local caching
Modern DNS changes can sometimes become visible quickly, while other cached results may persist until their applicable TTL expires.
What Is a DNS Cache Flush?
A DNS cache flush removes locally cached DNS information.
This can be useful when troubleshooting DNS problems.
How to Flush DNS Cache in Windows
Open Command Prompt as appropriate and run:
ipconfig /flushdns
Windows should report that the DNS resolver cache has been successfully flushed.
After that, your computer can perform fresh DNS lookups instead of relying on the previous local cache.
What Is Public DNS?
A public DNS resolver is a DNS service that users can configure instead of automatically using their ISP’s resolver.
Popular public DNS services include:
- Cloudflare DNS
- Google Public DNS
- Quad9
Different DNS providers may offer different features, including performance, filtering, security-focused services and privacy policies.
Does Changing DNS Make Internet Faster?
It can sometimes improve DNS lookup performance, but changing DNS does not increase the physical speed of your internet connection.
For example, if your ISP’s DNS resolver is slow or unreliable, switching to another resolver may make websites begin loading more quickly.
However, DNS is only one part of the overall connection.
Does DNS Affect Website Speed?
Yes, but usually only during the DNS lookup portion of connecting to a website.
When DNS is fast, the browser can obtain the destination address quickly.
But once the connection is established, most of the page-loading time can depend on:
- Server response time
- Internet latency
- Website resources
- CDN performance
- Connection speed
- Browser processing
- Network congestion
Therefore, DNS is important, but it isn’t the only factor that determines website speed.
What Is DNS over HTTPS?
DNS over HTTPS (DoH) sends DNS queries through HTTPS.
Instead of sending traditional DNS queries in a way that can be observed by local network devices, DoH can encrypt the DNS communication between your device and the DoH resolver.
This can improve privacy against certain types of local network observation.
How Does DoH Work?
A simplified connection looks like:
Device → HTTPS connection → DNS Resolver
The DNS query is carried inside HTTPS traffic.
This can make DNS queries harder for someone on the local network to inspect directly.
What Is DNS over TLS?
DNS over TLS (DoT) is another technology for protecting DNS queries.
It uses TLS encryption to protect the communication between the device and DNS resolver.
The main difference is the transport:
DoH → DNS through HTTPS
DoT → DNS through TLS
Both can provide encrypted DNS communication when properly configured.
Does DNS Encryption Hide Everything?
No.
Encrypted DNS protects the DNS query itself between your device and the resolver.
It doesn’t automatically hide every part of your internet activity.
For example, websites can still see information associated with your connection, and HTTPS protects web traffic separately between your browser and the website.
A VPN can provide a different type of protection by encrypting traffic between your device and the VPN server.
What Is DNS Hijacking?
DNS hijacking occurs when DNS requests are redirected or manipulated so that a domain resolves to an unintended destination.
This can happen through:
- Compromised routers
- Malicious software
- Network attacks
- Unauthorized DNS configuration changes
- Malicious or compromised DNS infrastructure
Why Is DNS Hijacking Dangerous?
If DNS information is manipulated, a user could potentially be directed to an unintended website.
This is one reason why DNS security and HTTPS are both important.
What Is DNS Spoofing?
DNS spoofing refers to providing false DNS information so that a domain name resolves to an incorrect IP address.
For example, instead of:
bank.example → legitimate server
a manipulated DNS response might direct the user somewhere else.
Modern DNS security mechanisms and encrypted connections can help mitigate different types of attacks, but no single technology solves every security problem.
What Is DNSSEC?
DNSSEC (Domain Name System Security Extensions) adds cryptographic authentication to DNS responses.
It helps DNS resolvers verify that DNS information came from the correct authoritative source and hasn’t been improperly modified.
Does DNSSEC Encrypt DNS?
No.
DNSSEC provides authentication and integrity, not encryption.
This is an important distinction.
DNSSEC: Helps verify DNS data.
DoH/DoT: Protect DNS communication with encryption.
They solve different problems and can be used in complementary ways.
Why Does DNS Sometimes Stop Working?
If DNS is unavailable or misconfigured, your internet connection may appear to be broken even though the underlying network connection is working.
For example, you may be connected to Wi-Fi but unable to open websites because your device cannot resolve domain names.
Common DNS Problems
Possible causes include:
- DNS server outage
- Incorrect DNS configuration
- Router problems
- ISP DNS issues
- Local DNS cache problems
- Incorrect DNS records
- Network configuration errors
How Can You Tell If DNS Is the Problem?
One simple troubleshooting method is to compare domain-name access with direct IP connectivity.
If you can reach a service by IP but not by domain name, DNS may be involved.
However, modern websites often use multiple IP addresses, CDNs, virtual hosting and HTTPS, so this test isn’t always conclusive.
Useful DNS Commands
On Windows, you can use:
nslookup example.com
This command can show the DNS response for a domain.
For example:
nslookup google.com
can return the IP addresses associated with that domain.
Can DNS Block Websites?
Yes.
DNS services can be configured to filter or block domains.
For example, some DNS providers offer filtering for:
- Malware
- Phishing
- Adult content
- Advertisements
- Tracking domains
When a blocked domain is requested, the DNS service can return a different response instead of the normal DNS record.
Is DNS Blocking the Same as a Firewall?
No.
DNS filtering works at the domain-resolution level.
A firewall can operate at different layers and enforce more detailed network rules.
DNS filtering is therefore only one type of content or security control.
Can I Change My DNS Server?
Yes.
You can configure your DNS settings on:
- Windows
- Android
- iPhone
- macOS
- Routers
- Other network devices
You can either configure a DNS resolver manually or use one provided automatically by your ISP.
Should You Change Your DNS?
You don’t necessarily need to.
If your current DNS service is reliable and fast, there may be little reason to change it.
You might consider another resolver if you want:
- Different privacy policies
- Security filtering
- Parental controls
- Better reliability
- Different DNS features
DNS vs IP Address
DNS and IP addresses work together, but they are not the same thing.
DNS: Helps translate domain names into network information.
IP address: Identifies a network destination.
For example:
Domain: example.com
↓
DNS lookup
↓
IP address: 203.0.113.10
↓
Your browser connects to the server
This is why DNS is such an important part of everyday internet use.
Final Thoughts
DNS is one of the most important but often overlooked systems that makes the internet easy to use.
Instead of forcing people to remember IP addresses, DNS lets us use simple domain names such as google.com, youtube.com, or mindfultomorrow.com.
When you enter a domain into your browser, your device can use a DNS resolver to find the appropriate IP address. The resolver may use cached information or query the DNS hierarchy, including root servers, TLD servers and authoritative DNS servers.
DNS also does much more than simply translate names into IP addresses. Different DNS records can handle websites, email servers, domain verification and other services.
Technologies such as DNSSEC, DNS over HTTPS, and DNS over TLS provide additional capabilities related to DNS integrity, privacy and security.
The next time you type a website name into your browser, remember that DNS is working behind the scenes to help your device find the right destination.
Frequently Asked Questions
What does DNS stand for?
DNS stands for Domain Name System.
What does DNS do?
DNS translates human-readable domain names into IP addresses and provides other information about domains and network services.
Is DNS like the internet’s phonebook?
Yes. This is a useful beginner-friendly analogy because DNS helps translate names that people can remember into information computers use to connect to services.
What is a DNS server?
A DNS server is a system that stores or retrieves DNS information and responds to DNS queries.
What is a DNS resolver?
A DNS resolver receives DNS queries from clients and finds the appropriate DNS information, often by querying other DNS servers when the answer isn’t already cached.
What is a DNS record?
A DNS record is a piece of information stored in DNS. Common examples include A, AAAA, CNAME, MX, TXT and NS records.
What is an A record?
An A record maps a domain name to an IPv4 address.
What is an AAAA record?
An AAAA record maps a domain name to an IPv6 address.
What is an MX record?
An MX record specifies which mail servers handle email for a domain.
What is DNS caching?
DNS caching is the temporary storage of DNS information so that future lookups can be answered more quickly.
What is DNS propagation?
DNS propagation refers to the process by which DNS changes become visible through different DNS resolvers and networks as cached information expires or is refreshed.
What is DNSSEC?
DNSSEC adds cryptographic authentication to DNS data so resolvers can verify the integrity and authenticity of DNS responses.
Does DNSSEC encrypt DNS?
No. DNSSEC provides authentication and integrity, not encryption.
What is DNS over HTTPS?
DNS over HTTPS, or DoH, sends DNS queries through an HTTPS connection, helping protect the communication between the device and the DNS resolver.
What is DNS over TLS?
DNS over TLS, or DoT, protects DNS queries using TLS encryption between the client and DNS resolver.
Can changing DNS improve internet speed?
It can sometimes improve the speed or reliability of DNS lookups, but it doesn’t increase the actual bandwidth of your internet connection.
Can DNS block websites?
Yes. Some DNS services provide filtering that can block access to particular domains.
Can I change my DNS server?
Yes. DNS settings can be changed on computers, smartphones, routers and other network devices.
What happens if DNS stops working?
You may still have an active network connection, but websites may fail to load because your device cannot translate domain names into IP addresses.
Is DNS the same as an IP address?
No. DNS is a naming and information system, while an IP address is a network address used to identify a destination for IP traffic.
