Networking · 10 min read · May 18, 2026 · IPLocatorTools

What is DNS and How Does It Work? Complete Beginner Guide

DNS translates domain names into IP addresses. Without it, you would need to memorise numbers to visit any website. Here is exactly how it works.

Every time you type a website address into your browser, something happens silently in the background before the page loads. Your device asks a series of servers a simple question: what is the IP address for this domain name? The system that answers that question is called DNS — the Domain Name System. It is one of the most fundamental building blocks of the internet, yet most people have never thought about how it works.

What is DNS?

DNS stands for Domain Name System. It is a distributed database that maps human-readable domain names (like google.com or bbc.co.uk) to the numerical IP addresses that computers actually use to communicate (like 142.250.80.46).

Think of DNS as the internet's phone book. Phone books map names (John Smith) to phone numbers (555-1234). DNS maps domain names (google.com) to IP addresses (142.250.80.46). Without DNS, you would need to memorise the IP address of every website you want to visit — clearly impractical.

The Domain Name System was invented in 1983 by Paul Mockapetris to replace a simple text file called HOSTS.TXT that was manually updated and shared between all computers on the early internet. As the internet grew from a few hundred machines to millions, a centralised text file became unmanageable. DNS solved this by creating a distributed, hierarchical system that could scale to billions of domains.

How a DNS Lookup Works — Step by Step

When you type iplocatortools.com into your browser, here is exactly what happens:

Step 1: Check the Local Cache

Your device first checks its local DNS cache — a small database of recently looked up domain names and their IP addresses stored in your computer's memory. If you visited iplocatortools.com recently and the record is still valid, your computer uses the cached IP address immediately without making any network request. This makes repeat visits to familiar websites nearly instantaneous.

Step 2: Ask the Recursive Resolver

If the answer is not in your local cache, your device contacts a recursive DNS resolver — a server provided by your ISP, or one you have configured manually (like 8.8.8.8 from Google, 1.1.1.1 from Cloudflare, or 9.9.9.9 from Quad9).

The recursive resolver acts as your agent. It does the hard work of finding the answer and returns it to your device.

Step 3: The Resolver Asks the Root Nameservers

The recursive resolver first contacts one of the root nameservers — 13 sets of servers distributed worldwide that know the authoritative nameservers for every top-level domain (TLD) like .com, .org, .uk, .io, etc.

The root server does not know the IP for iplocatortools.com directly. It knows who is responsible for .com domains and returns the address of the TLD nameserver for .com.

Step 4: Ask the TLD Nameserver

The recursive resolver contacts the TLD nameserver for .com (operated by Verisign). The TLD nameserver knows which nameservers are authoritative for iplocatortools.com — these are the nameservers registered by the domain's owner. It returns their addresses.

Step 5: Ask the Authoritative Nameserver

The recursive resolver contacts the authoritative nameserver for iplocatortools.com — the server that has the actual DNS records for the domain. This is typically operated by the domain registrar or hosting provider. The authoritative nameserver returns the A record (IPv4 address) for iplocatortools.com.

Step 6: Return the Answer and Cache It

The recursive resolver sends the IP address back to your device. Both the resolver and your device cache the answer for the duration of the record's TTL (Time To Live) — a value in seconds set by the domain owner. A TTL of 3600 means the record is cached for 1 hour before it needs to be looked up again.

Step 7: Your Browser Connects

Now your browser has the IP address. It opens a TCP/TLS connection to that IP and requests the web page. The DNS process is complete — all of this typically happens in under 50 milliseconds.

DNS Record Types Explained

DNS is not just a simple name-to-IP mapping. Each domain can have many different types of DNS records serving different purposes:

A Record (Address Record)

Maps a domain name to an IPv4 address. The most fundamental DNS record type.

Example: iplocatortools.com → 76.76.21.21

A records control where your website's traffic is sent. When you change hosting providers, you update your A record to point to the new server's IP address.

AAAA Record (IPv6 Address Record)

Maps a domain name to an IPv6 address. The quad-A record is the IPv6 equivalent of the A record.

Example: iplocatortools.com → 2606:4700:3108::ac42:2ae7

As IPv4 addresses run out, more websites are adding AAAA records to support IPv6 connections.

MX Record (Mail Exchange Record)

Specifies which servers receive email for a domain. Every domain that accepts email must have at least one MX record. MX records also have a priority value — lower numbers mean higher priority.

Example: iplocatortools.com MX 10 mail.iplocatortools.com

If your emails are not being delivered, a missing or misconfigured MX record is a common cause. Use the DNS Lookup tool to check MX records for any domain.

TXT Record (Text Record)

Stores arbitrary text associated with a domain. TXT records are used for a wide variety of purposes:

SPF (Sender Policy Framework) — Lists which mail servers are authorised to send email on behalf of the domain. Email servers check SPF records to decide whether to accept or reject incoming email.

DKIM (DomainKeys Identified Mail) — Stores a public key used to verify that emails from the domain have not been tampered with in transit.

DMARC — Specifies what email servers should do with messages that fail SPF or DKIM checks.

Domain verification — Google Search Console, Mailchimp, and many other services ask you to add a specific TXT record to prove you own a domain.

NS Record (Nameserver Record)

Specifies which nameservers are authoritative for the domain. When you register a domain, you set NS records pointing to your hosting provider's or DNS service's nameservers.

Example: iplocatortools.com NS ns1.vercel-dns.com

CNAME Record (Canonical Name Record)

Creates an alias that points one domain name to another domain name (not directly to an IP address). CNAME records are commonly used for subdomains.

Example: www.iplocatortools.com CNAME iplocatortools.com

This means requests for www.iplocatortools.com are resolved by looking up the A record for iplocatortools.com. Important: you cannot use a CNAME for the root domain (@), only for subdomains.

SOA Record (Start of Authority)

Contains administrative information about the DNS zone — the primary nameserver, the email of the zone administrator, and timing parameters for zone transfers. Every DNS zone must have exactly one SOA record.

PTR Record (Pointer Record)

The reverse of an A record — maps an IP address to a domain name. PTR records are used for reverse DNS lookups. Email servers use PTR records to verify that the sending mail server's IP resolves back to a legitimate hostname — missing PTR records are a common reason for email rejection.

You can look up any of these record types using the DNS Lookup tool — just enter any domain and select the record type you want to query.

What is DNS Propagation?

When you change a DNS record — for example, updating your A record to point to a new hosting server — the change does not take effect instantly worldwide. DNS records are cached by resolvers around the world for the duration of their TTL.

If your A record has a TTL of 3600 (1 hour), resolvers that have recently cached the old record will continue using it for up to 1 hour after you make the change. After their cached version expires, they will fetch the new record from your authoritative nameserver.

Full global DNS propagation typically takes:

• Minutes to a few hours for records with short TTLs (300–3600 seconds)
• Up to 48 hours for records with long TTLs (86400 seconds = 24 hours)

If you are planning a hosting migration, lower your TTL to 300 seconds (5 minutes) at least 24 hours before the migration. This reduces the propagation wait to just a few minutes once you make the change. After the migration is stable, you can raise the TTL back to a higher value.

Public DNS Resolvers vs ISP DNS

By default, your device uses your ISP's DNS resolver. You can change this to a public resolver, which offers potential benefits:

| Resolver | Provider | Focus | Address | |----------|----------|-------|---------| | 1.1.1.1 | Cloudflare | Privacy, speed | 1.1.1.1 / 1.0.0.1 | | 8.8.8.8 | Google | Speed, reliability | 8.8.8.8 / 8.8.4.4 | | 9.9.9.9 | Quad9 | Security (blocks malicious domains) | 9.9.9.9 | | 208.67.222.222 | OpenDNS | Parental controls, reliability | 208.67.222.222 |

Privacy consideration: Your DNS resolver can see every domain you look up — even if the connection to the website is encrypted (HTTPS). Your ISP's resolver gives them a complete record of every domain you visit.

Cloudflare's 1.1.1.1 is operated with a privacy-first commitment and does not store personally identifiable DNS query logs. Google's 8.8.8.8 is fast but Google retains some DNS data. Quad9 blocks known malicious domains automatically, making it a good choice for family networks.

DNS over HTTPS (DoH) and DNS over TLS (DoT)

Traditional DNS queries are sent in plain text — anyone monitoring your network (your ISP, a hacker on public Wi-Fi) can see every domain you look up, even if the websites themselves use HTTPS.

DNS over HTTPS (DoH) encrypts DNS queries by sending them as HTTPS requests to a DNS resolver that supports it. From a network monitoring perspective, your DNS queries are indistinguishable from regular HTTPS web traffic.

DNS over TLS (DoT) encrypts DNS queries using TLS on port 853. Functionally similar to DoH but uses a dedicated port, which makes it easier to monitor or block (useful for network administrators).

Modern browsers like Chrome and Firefox support DoH natively and can be configured to use encrypted DNS regardless of your operating system settings. This provides DNS privacy even on untrusted networks.

DNS Security: DNSSEC

The original DNS protocol has no built-in authentication. A resolver has no way to verify that the answer it received is genuine and has not been tampered with. This creates vulnerability to DNS spoofing (also called DNS cache poisoning) — an attack where a malicious actor injects false DNS records into a resolver's cache, redirecting traffic intended for legitimate domains to malicious servers.

DNSSEC (DNS Security Extensions) adds cryptographic signing to DNS records. Each record is signed with the domain owner's private key, and resolvers can verify signatures using the corresponding public key published in the DNS hierarchy. If a record has been tampered with, the signature verification fails and the resolver rejects the record.

DNSSEC is supported by most major TLDs and registrars but requires the domain owner to enable it explicitly. Many websites do not use DNSSEC yet, leaving them theoretically vulnerable to cache poisoning attacks on networks with malicious resolvers.

Common DNS Problems and How to Fix Them

Website not loading after DNS change — DNS propagation is still in progress. Wait up to 48 hours, or flush your local DNS cache. On Windows: open Command Prompt and run ipconfig /flushdns. On Mac: open Terminal and run sudo dscacheutil -flushcache. On Linux: run sudo systemd-resolve --flush-caches.

Emails not being received — Check your MX records using the DNS Lookup tool. Also check that your SPF record in TXT records includes all mail servers you use. A misconfigured SPF record causes email rejection at receiving mail servers.

"This site can't be reached" error — Could be a missing or misconfigured A record, or DNS propagation in progress after a recent change. Use the DNS Lookup tool to check if the A record resolves to the expected IP.

Slow website loading — Can be caused by slow DNS resolution. Try switching your device's DNS resolver to 1.1.1.1 or 8.8.8.8. These are typically faster than ISP-provided resolvers.

How to Look Up DNS Records

You can query DNS records for any domain using the DNS Lookup tool at IPLocatorTools. Enter any domain name, select the record type (A, MX, TXT, NS, etc.), and click Lookup. The tool uses Cloudflare's DNS-over-HTTPS API for fast, private queries.

This is useful for:

• Verifying your DNS records after making changes
• Checking if DNS propagation has completed
• Troubleshooting email delivery problems (MX, TXT/SPF)
• Researching domain configurations
• Finding the IP address a domain resolves to

Frequently Asked Questions

What is a DNS server? A DNS server is a computer that answers DNS queries. Your ISP operates DNS servers for its customers. Public resolvers like Cloudflare's 1.1.1.1 and Google's 8.8.8.8 are also DNS servers, available for anyone to use.

How do I find what DNS server I am using? On Windows, open Command Prompt and type ipconfig /all — look for "DNS Servers" under your active network adapter. On Mac, go to System Preferences → Network → your connection → Advanced → DNS tab.

Can I use any DNS server? Yes. You can change your DNS server in your device's network settings or router settings. Popular choices are Cloudflare (1.1.1.1), Google (8.8.8.8), and Quad9 (9.9.9.9).

What is the difference between a domain and a DNS record? A domain is a human-readable name you register (like example.com). DNS records are the database entries that map that domain to servers — A records for web traffic, MX records for email, TXT records for verification, and so on.

What causes a DNS error? Common causes: your DNS resolver is down or unreachable, the domain's DNS records are misconfigured, DNS propagation is in progress after a recent change, or your device's DNS cache has a stale entry. Flushing your DNS cache and trying a public resolver usually resolves the issue.

Related Tools

Use the DNS Lookup tool to query any DNS record type for any domain — A, AAAA, MX, NS, TXT, CNAME, SOA, and PTR records. Check the IP Lookup tool to see the IP address your current connection resolves from. Use Domain Tools for WHOIS registration data, reverse DNS, and domain availability checks.