Cloudflare CNAME flattening allows us to use a CNAME record at our root/apex domain, which speeds up CNAME resolution.

As part of our Server administration services, Bobcares responds to all queries, large and small.

Let’s look at Cloudflare’s CNAME flattening in more detail.

Cloudflare CNAME flattening

Cloudflare uses CNAME flattening to find the IP address that a CNAME points to. This procedure could include a single or multiple lookups (if your CNAME points to another CNAME). Cloudflare then returns the final IP address rather than a CNAME record, which speeds up DNS query resolution by up to 30%.

A domain cannot have a CNAME record and a different type of DNS record if both records have the same name, according to DNS specifications (RFCs). When we need a CNAME for our root domain but also need another type of DNS record at the root domain, such as an MX record for mail delivery, this becomes a problem.

Normally, the aforementioned circumstance would result in email delivery issues. CNAME Flattening, on the other hand, ensures that the chain of CNAMEs leads to an A or AAAA record, allowing mail delivery while still adhering to DNS RFCs. DNS TTLs are respected and CNAME responses are cached. If the corresponding DNS CNAME record in the Cloudflare dashboard’s DNS app is “grey cloud,” CNAME Flattening will still work.

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Set up CNAME flattening​​

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For your root domain

When our domain uses a CNAME record for its root domain, CNAME flattening is enabled by default for all plans.

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For all CNAME records

Flattening all CNAME records on a domain is an option available to paid plans. Since proxied records are flattened by default, this option is useful for DNS-only (unproxied) CNAME records.

1. Firstly, go to Cloudflare’s dashboard and choose the account and domain.
2. Then, navigate to DNS.
3. Finally, select Flatten all CNAMEs for CNAME Flattening.

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How to change settings for CNAME Flattening​​

CNAME Flattening can’t be turned off. Domains are set up by default to only flatten CNAME records at the root domain.

We can apply CNAME Flattening to CNAMEs at the root domain or to all CNAMEs within a domain on the Pro, Business, and Enterprise plans. Select Flatten all CNAMEs from the CNAME Flattening dropdown menu in the Cloudflare dashboard’s DNS app to flatten all CNAMEs in the domain.

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Conclusion

To sum up, our Skilled engineers demonstrated Cloudflare’s CNAME flattening in greater depth.