What are DNS records and what do they do? This plain-English guide explains every DNS record type — A, AAAA, CNAME, MX, NS, TXT, SOA — and when each one matters.
DNS is often described as the "phone book of the internet" — but that analogy only tells part of the story. DNS doesn't just map domain names to IP addresses. It controls where your email goes, who hosts your website, whether your HTTPS works, and whether you're protected against email spoofing.
Understanding DNS records is essential for anyone who manages a website. Here's everything you need to know, in plain English.
What Is DNS?
DNS stands for Domain Name System. It's a globally distributed database that translates human-readable domain names (like example.com) into the IP addresses that computers use to communicate (like 192.168.1.1).
When you type a URL into your browser, your computer queries DNS to find out where to send the request. This lookup happens in milliseconds, behind the scenes, every time someone visits your site.
The Most Important DNS Record Types
A Record (Address Record)
Maps a domain name to an IPv4 address. This is the most fundamental DNS record — it tells browsers which server to connect to.
- Example:
example.com → 192.168.1.100 - Used for: pointing your domain to your web host's server
AAAA Record
The IPv6 equivalent of an A record. Maps a domain to an IPv6 address (the newer, longer format).
- Example:
example.com → 2001:db8::1 - Used for: supporting modern IPv6 networks alongside IPv4
CNAME Record (Canonical Name)
Creates an alias that points one domain name to another domain name (not an IP address directly).
- Example:
www.example.com → example.com - Used for: pointing subdomains to your main domain, or routing traffic through a CDN
MX Record (Mail Exchange)
Specifies which mail servers receive email for your domain. Priority numbers determine which server is tried first.
- Example:
example.com → mail.google.com (Priority: 1) - Used for: setting up email hosting (Gmail, Outlook, custom mail server)
NS Record (Name Server)
Identifies the authoritative name servers for your domain — the servers that hold all your DNS records. These are set at your domain registrar.
- Example:
example.com → ns1.hostingprovider.com - Used for: delegating DNS management to your hosting provider or DNS service
TXT Record (Text Record)
Stores arbitrary text data. Critical for email authentication and domain verification. Common uses:
- SPF — specifies which servers are authorized to send email for your domain
- DKIM — a cryptographic signature that verifies email authenticity
- DMARC — tells receiving servers what to do with suspicious email
- Domain verification — Google Search Console, Microsoft, and others use TXT records to verify domain ownership
SOA Record (Start of Authority)
Contains administrative information about your DNS zone — the primary name server, the email of the zone administrator, and timing parameters for zone transfers. Usually managed automatically by your DNS provider.
Why DNS Records Matter for Your Website
- Wrong A record? Your website won't load — browsers can't find your server.
- Missing or wrong MX records? Email sent to your domain bounces or disappears.
- Missing SPF/DKIM/DMARC TXT records? Your emails land in spam folders or get rejected entirely.
- Misconfigured CNAME? Your
wwwsubdomain stops working or loops endlessly.
DNS issues are responsible for a significant portion of "my website is down" situations. The good news is they're usually quick to diagnose and fix once you can see the actual records.
How to Check DNS Records for Any Domain
A free DNS lookup tool lets you instantly query and view all DNS records for any domain. This is useful for:
- Diagnosing why a website isn't loading
- Verifying DNS changes have propagated after switching hosts
- Checking if email authentication records (SPF, DKIM, DMARC) are properly configured
- Researching a competitor's hosting and email infrastructure
- Confirming your CDN's CNAME record is working
DNS Propagation: Why Changes Take Time
When you update a DNS record, the change doesn't appear instantly worldwide. Each DNS record has a TTL (Time to Live) value — a number in seconds that tells DNS resolvers how long to cache the record before checking for updates.
Propagation typically takes 15 minutes to 48 hours depending on the TTL value. During this window, some users around the world may see the old record while others see the new one.
Pro tip: Before a major DNS change (like migrating to a new host), reduce your TTL to 300 seconds (5 minutes) a day in advance. This minimizes the propagation window. After the migration is stable, increase the TTL back to 3600 (1 hour) or higher.