What are DNS records (A, AAAA, MX, CNAME, etc.)?

If you’ve ever set up a website or managed a domain, you’ve probably encountered DNS records. These little pieces of information are crucial for making the internet work, yet many people find them confusing.

In this guide, we’ll break down the most common DNS record types—like A, AAAA, MX, CNAME, TXT, and others—in simple, human-friendly terms. By the end, you’ll understand what they do, why they matter, and how to use them effectively.

What Are DNS Records?

DNS (Domain Name System) records are like the internet’s phonebook. They translate human-friendly domain names (like example.com) into machine-readable IP addresses (like 192.0.2.1). Without DNS, you’d have to memorize long strings of numbers to visit websites—definitely not user-friendly! Each DNS record has a type that serves a specific purpose. Let’s explore the most important ones.

1. A Record (Address Record)

What It Does:

The A record (or “Address” record) connects a domain name to an IPv4 address (e.g., 192.0.2.1).

Example Use Case:

When you type example.com in your browser, the A record tells the computer, “Go to this IP address to find the website.”

How It Looks in DNS Settings:

example.com.   A   192.0.2.1

Why It Matters:

• Essential for hosting websites.

• Without an A record, your domain won’t load.

2. AAAA Record (IPv6 Address Record)

What It Does:

Similar to the A record, but for IPv6 addresses (longer, newer IP format like 2001:0db8:85a3::8a2e:0370:7334).

Example Use Case:

If your server supports IPv6, the AAAA record ensures users with IPv6 connections can reach your site.

How It Looks in DNS Settings:

example.com.   AAAA   2001:0db8:85a3::8a2e:0370:7334

Why It Matters:

• Future-proofs your domain as IPv6 adoption grows.

• Needed if your hosting provider uses IPv6.

3. CNAME Record (Canonical Name Record)

What It Does:

A CNAME record aliases one domain name to another. Instead of pointing to an IP, it points to another domain.

Example Use Case:

You want www.example.com to point to example.com. Instead of setting two A records, you use a CNAME:

How It Looks in DNS Settings:

www.example.com.   CNAME   example.com.

Why It Matters:

• Simplifies DNS management (change one A record instead of multiple).

• Commonly used for subdomains (e.g., blog.example.com pointing to a third-party service).

Limitations:

• Can’t be used for the root domain (example.com must use an A or AAAA record).

• Adds a tiny delay since the DNS must resolve twice.

4. MX Record (Mail Exchange Record)

What It Does:

The MX record directs emails to the right mail server.

Example Use Case:

When someone sends an email to you@example.com, the MX record tells where to deliver it (e.g., Google Workspace or your private email server).

How It Looks in DNS Settings:

example.com.   MX   10 mail.example.com.

(The “10” is a priority value—lower numbers get tried first.)

Why It Matters:

• No MX record = no email delivery.

• Critical for business communications.

5. TXT Record (Text Record)

What It Does:

Stores text-based information for verification, security, and configuration.

Example Use Cases:

• SPF/DKIM/DMARC (email security to prevent spam).

• Domain ownership verification (e.g., for Google Search Console).

• SSL certificate validation.

How It Looks in DNS Settings:

example.com.   TXT   "v=spf1 include:_spf.google.com ~all"

Why It Matters:

• Improves email deliverability.

• Required for many security validations.

6. NS Record (Name Server Record)

What It Does:

Tells the internet which DNS servers are authoritative for your domain.

Example Use Case:

When you buy a domain from GoDaddy but host DNS on Cloudflare, you update NS records to point to Cloudflare’s servers.

How It Looks in DNS Settings:

example.com.   NS    ns1.cloudflare.com.  
example.com.   NS    ns2.cloudflare.com.

Why It Matters:

• Wrong NS records = your DNS won’t work.

• Essential when changing hosting providers.

7. SOA Record (Start of Authority Record)

What It Does:

Contains admin details about the DNS zone (like contact email, serial number, refresh rate).

Example Use Case:

Secondary DNS servers check the SOA record to see if they need to update their cached records.

How It Looks in DNS Settings:

example.com.   SOA   ns1.example.com. admin.example.com. (  
                    2024051901 ; serial  
                    3600       ; refresh  
                    1800       ; retry  
                    604800     ; expire  
                    86400 )    ; minimum TTL

Why It Matters:

• Controls DNS propagation behavior.

• Rarely edited manually but crucial for DNS stability.

8. PTR Record (Pointer Record)

What It Does:

The reverse of an A record—it maps an IP address back to a domain.

Example Use Case:

Used in reverse DNS lookups, important for email servers to verify sender legitimacy.

How It Looks in DNS Settings:

1.2.0.192.in-addr.arpa.   PTR   example.com.

Why It Matters:

• Helps prevent emails from being marked as spam.

• Mostly managed by hosting providers.

9. SRV Record (Service Record)

What It Does:

Specifies a server and port for specific services (like VoIP, gaming, or autodiscovery).

Example Use Case:

Microsoft Exchange uses SRV records for automatic email client configuration.

How It Looks in DNS Settings:

_sip._tcp.example.com.   SRV   10 60 5060 sipserver.example.com.

(Priority: 10, Weight: 60, Port: 5060, Target: sipserver.example.com)

Why It Matters:

• Enables automatic service discovery.

• Used in specialized applications.

How to Check Your DNS Records?

Want to see your current DNS records? Use these tools:

• Command Line: nslookup, dig

• Online Tools: MXToolbox, DNS Checker

Final Thoughts

DNS records might seem technical, but they’re just instructions telling the internet how to handle your domain. Whether you’re setting up a website, email, or subdomains, understanding these records helps you troubleshoot issues and optimize performance.