What Is DNS?
The Domain Name System (DNS) is one of the core systems that makes the internet easier to use. Instead of requiring people to remember numerical IP addresses, DNS allows websites and internet services to use readable names such as example.com.
What does DNS stand for?
DNS stands for Domain Name System.
It is a distributed naming system used to connect human-readable domain names with information computers need in order to communicate across networks.
One of its most familiar jobs is translating a domain name such as:
example.com
into an IP address that can be used to reach the server hosting the service.
Why do we need DNS?
Computers communicate using network addresses, but numerical addresses are not convenient for people to remember.
Imagine needing to remember an IP address every time you wanted to visit a website. DNS allows users to work with memorable domain names instead.
In that sense, DNS acts somewhat like a directory that connects names with network destinations.
How does DNS work?
When you enter a domain name into a browser, your device needs to determine where that domain can be reached.
A simplified DNS lookup may work like this:
- You enter a domain name in your browser.
- Your device checks whether it already has a cached answer.
- If necessary, the request is sent to a DNS resolver.
- The resolver searches for the authoritative DNS information.
- The relevant DNS record is returned.
- Your device can then connect to the appropriate destination.
In many cases this entire process takes only a fraction of a second.
What is a DNS resolver?
A DNS resolver receives DNS queries and helps find the answer.
Your internet provider may operate a DNS resolver, or you may use a public DNS service or another resolver configured on your device or router.
Recursive resolvers can contact other DNS servers when they do not already have the requested information cached.
What are root DNS servers?
The DNS hierarchy begins with the root.
Root servers do not normally store the final IP address for every website. Instead, they help direct resolvers toward the appropriate Top-Level Domain (TLD) servers.
For example, a lookup involving a .com domain may ultimately require information associated with the DNS infrastructure responsible for that top-level domain.
What is a TLD DNS server?
A Top-Level Domain server helps identify the authoritative name servers responsible for domains within extensions such as:
- .com
- .org
- .net
- .info
- country-code domains
The resolver can then continue the lookup by contacting the authoritative DNS server for the requested domain.
What is an authoritative DNS server?
An authoritative DNS server provides DNS records for a domain it is responsible for.
If a resolver asks for the IPv4 address associated with a hostname, the authoritative server may return an A record.
For IPv6, it may return an AAAA record.
DNS lookup example
Suppose you type:
www.example.com
Your device needs to discover the network information associated with that name.
A simplified path might look like:
Browser → DNS Resolver → Root → TLD → Authoritative DNS → Answer
In practice, caching often makes the process shorter because previously retrieved answers may already be available.
What are DNS records?
DNS records store different kinds of information associated with a domain. Each record type has a particular purpose.
| Record | Purpose |
|---|---|
| A | Maps a hostname to an IPv4 address |
| AAAA | Maps a hostname to an IPv6 address |
| CNAME | Creates an alias from one hostname to another |
| MX | Identifies mail servers for a domain |
| NS | Identifies authoritative name servers |
| TXT | Stores text information used for many verification and policy purposes |
| PTR | Used for reverse DNS lookups |
What is an A record?
An A record maps a hostname to an IPv4 address.
For example, a DNS response may indicate that a hostname should connect to an address similar to:
203.0.113.25
The browser can then use that address when establishing a connection.
What is an AAAA record?
An AAAA record performs a similar role for IPv6.
A hostname could therefore point to an IPv6 address such as:
2001:db8:1234::25
A domain may have both A and AAAA records when its services support IPv4 and IPv6.
What is a CNAME record?
A CNAME record identifies one hostname as an alias of another hostname.
Instead of pointing directly to an IP address, it points to another DNS name.
This can make it easier to manage services when multiple names ultimately rely on the same destination.
What is an MX record?
An MX record identifies the mail servers responsible for receiving email for a domain.
A domain may have multiple MX records with different priorities so mail systems know which server should be attempted first.
What is a TXT record?
A TXT record stores text data associated with a domain.
TXT records are commonly used for:
- domain ownership verification,
- email authentication policies,
- service configuration,
- and other machine-readable information.
What is a reverse DNS lookup?
A normal DNS lookup often starts with a hostname and looks for an address.
A reverse DNS lookup starts with an IP address and attempts to find a hostname associated with that address.
Reverse DNS commonly uses PTR records.
Reverse DNS is frequently used in network administration, logging, diagnostics, and email infrastructure.
What is DNS caching?
DNS would be much slower if every lookup had to repeat the entire hierarchy from the beginning.
For this reason, DNS information can be temporarily stored in a cache.
Caching may occur at several levels, including:
- your browser,
- your operating system,
- your router,
- and recursive DNS resolvers.
If a valid cached answer exists, the DNS response can be returned without repeating the complete lookup process.
What is DNS TTL?
TTL stands for Time To Live.
In DNS, TTL indicates how long a resolver or other system may cache a record before it should obtain updated information.
A shorter TTL can allow changes to be noticed sooner, while a longer TTL can reduce the number of DNS queries required.
What does DNS propagation mean?
The term DNS propagation is commonly used to describe the period during which DNS changes are not yet reflected everywhere.
In many cases, the delay is caused by existing cached records that remain valid until their TTL expires.
This is why changing a DNS record does not always produce an immediate visible change for every user.
Can DNS fail?
Yes.
A DNS problem can prevent a domain name from resolving correctly even when the destination server itself is operating normally.
Symptoms may include:
- a website failing to load by name,
- DNS lookup errors,
- email delivery problems,
- incorrect destination addresses,
- or intermittent access while cached records differ.
What causes DNS problems?
Common causes include:
- incorrect DNS records,
- expired or stale cached information,
- misconfigured name servers,
- temporary resolver outages,
- network connectivity problems,
- or domain configuration errors.
What is DNSSEC?
DNSSEC stands for Domain Name System Security Extensions.
DNSSEC adds cryptographic validation to DNS data so a validating resolver can verify that certain DNS responses are authentic and have not been altered.
DNSSEC does not encrypt the DNS query itself. Its primary purpose is authenticity and integrity of signed DNS information.
Is DNS traffic encrypted?
Traditional DNS queries are commonly sent without encryption.
Modern technologies can protect DNS queries in transit, including:
- DNS over HTTPS (DoH)
- DNS over TLS (DoT)
These technologies encrypt communication between the client and the DNS resolver being used.
They do not make all internet activity anonymous, but they can prevent unencrypted DNS queries from being observed or modified along that part of the network path.
Does changing DNS change your IP address?
Normally, no.
Changing the DNS resolver you use does not normally change the public IP address assigned to your internet connection.
DNS determines how names are resolved, while your public IP address is part of your network connection.
These are different functions.
Does DNS hide your location?
DNS itself is not a location-hiding technology.
Changing DNS providers does not normally hide the public IP address seen by websites you visit.
Technologies such as VPNs operate differently because they can change the network endpoint through which your traffic reaches websites.
DNS vs IP address
| DNS | IP address |
|---|---|
| Helps translate names into network information | Identifies a network destination or interface |
| Example: example.com | Example: 203.0.113.25 |
| Uses records such as A, AAAA, MX, and TXT | Uses IPv4 or IPv6 addressing |
How can I check DNS records?
DNS lookup tools can query individual record types for a domain.
IPScope includes a DNS lookup utility on the Network Toolbox .
Enter a domain name, select the DNS record type, and run the lookup to inspect the information returned by DNS.
When is a DNS lookup useful?
DNS lookups can help when:
- checking where a hostname points,
- troubleshooting a website that will not resolve,
- verifying email configuration,
- checking name servers,
- confirming recent DNS changes,
- or investigating network configuration.
Does a domain have only one IP address?
Not necessarily.
A domain or hostname may return multiple addresses. Large websites and online platforms often use several servers or distributed infrastructure.
A hostname can also have both IPv4 and IPv6 records.
Can multiple domains use the same IP address?
Yes.
Modern web servers and hosting platforms can host many domain names using the same IP address.
The server can determine which website the visitor requested and serve the appropriate content.
DNS is the distributed naming system that helps connect domain names with network information such as IP addresses. Resolvers, root servers, TLD servers, authoritative name servers, records, and caching work together so users can reach internet services using memorable names instead of numerical addresses.
Related IP & network guides
To understand the addresses returned by DNS, start with What Is an IP Address? .
Learn how IPv4 and IPv6 addresses differ in IPv4 vs IPv6 .
To understand the address currently presented by your internet connection, read How to Check Your Public IP .
For changing and fixed internet addresses, see Dynamic vs Static IP .
