DNS A vs AAAA vs CNAME Records: What Is the Difference?

A, AAAA, and CNAME records are common when connecting domains to websites, APIs, CDNs, and hosting platforms.

Duck Cloud's DNS Lookup can inspect public A, AAAA, CNAME, MX, TXT, and NS records.

A record

An A record maps a hostname to an IPv4 address.

example.com → 203.0.113.10

AAAA record

An AAAA record maps a hostname to an IPv6 address.

example.com → 2001:db8::10

A hostname can have both A and AAAA records.

CNAME record

A CNAME aliases one hostname to another hostname.

www.example.com → hosting-provider.example.net

A CNAME target is a hostname, not an IP address.

Apex domains

Traditional DNS places restrictions on CNAME records at the zone apex. Some DNS providers offer flattening or alias-like behavior. Follow your provider's documentation.

www vs apex

A common setup uses an address or provider alias at the apex and a CNAME for www, then redirects one hostname to the preferred canonical hostname.

Use Redirect Checker to verify the redirect chain.

Common mistakes

• An old A record still points to a previous server.
• AAAA points to a broken IPv6 destination.
• A CNAME contains the wrong provider hostname.
• DNS looks correct but CDN/origin routing is wrong.
• Cached DNS still returns an old value.

Troubleshooting workflow

1. Run DNS Lookup.
2. Inspect A, AAAA, and CNAME.
3. Confirm expected destinations.
4. Test apex and www.
5. Inspect redirects.
6. Check Website Status Checker.

A maps to IPv4, AAAA maps to IPv6, and CNAME maps to another hostname.