This article describes the purpose, benefits, and limitations of enabling a CNAME setup for a Cloudflare domain.
A CNAME setup allows a customer to maintain authoritative DNS outside of Cloudflare. It allows individual subdomains to benefit from Cloudflare's services without requiring updates for a domain's registration to point to Cloudflare's nameservers for DNS resolution.
The logical flow of a DNS lookup for a domain on a CNAME setup is shown in the diagram below:
The CNAME setup has two limitations:
- DDOS protection for attacks against DNS infrastructure is only available for the delegated subdomain records.
- Only subdomains, not the root domain, can use Cloudflare's services. This limitation is imposed by Internet DNS specifications.