CNAME setup is available to paid Cloudflare plans at the Business or Enterprise level. 


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.  


Be careful not to confuse CNAME setup terminology with CNAME records which are available in the DNS app for all plan types.


The logical flow of a DNS lookup for a domain on a CNAME setup is shown in the diagram below:

CNAME_QUERY_PROCESS.png


Limitations

The CNAME setup has two limitations:

  1. DDOS protection for attacks against DNS infrastructure is only available for the delegated subdomain records.

  2. Only subdomains, not the root domain, can use Cloudflare's services. This limitation is imposed by Internet DNS specifications.


Add a redirect at your origin webserver (such as in an .htaccess file) to forward traffic for the root domain to a subdomain proxied to Cloudflare. 


Related resources

Configuring a CNAME setup