Glossary

CNAME Record

Definition: A DNS record that creates an alias pointing one domain name to another domain name rather than directly to an IP address.

A CNAME record (Canonical Name record) creates an alias — it points one domain name to another domain name. DNS then resolves the target domain to find the final IP address. This indirection makes CNAME records highly flexible for managing third-party services and subdomains.

How CNAME Works

www.example.com    IN    CNAME    example.com
shop.example.com   IN    CNAME    example.myshopify.com

When a browser looks up www.example.com, DNS follows the CNAME chain: www.example.com → example.com → A record → IP address.

When to Use CNAME

  • www subdomain → aliased to the root domain
  • Third-party services → shop.example.com → Shopify, help.example.com → Zendesk
  • CDN configuration → assets.example.com → your CDN hostname
  • Service verification → some services require a CNAME to verify domain ownership

CNAME Restrictions

  • Cannot be used on the root domain — example.com cannot be a CNAME (RFC 1912). Use ALIAS/ANAME records if your DNS provider supports them.
  • Cannot coexist with other records — A CNAME on a name cannot share that name with MX, NS or other records.
  • Avoid deep chains — CNAME → CNAME → CNAME adds latency and hits resolver limits.

CNAME vs A Record

  • Use A record when you have a fixed IP to point to directly.
  • Use CNAME when pointing to a hostname (especially third-party services where the IP may change).
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