Delegate subdomains

Subdomain delegation allows different individuals, teams, or organizations to manage different subdomains of a site.

Note

DNS delegation is not possible for Cloudflare domains using a CNAME setup (partial).

For instance, consider example.com as a Cloudflare domain with www.example.com managed in Cloudflare's DNS app and blog.example.com delegated to nameservers outside of Cloudflare. In this example, blog.example.com can now be managed by individuals who do not have access to Cloudflare credentials for the example.com domain.

Warning

Cloudflare's CDN and security services are not applied to delegated subdomains.

Availability

	Free	Pro	Business	Enterprise
Availability	Yes	Yes	Yes	Yes

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Delegate a subdomain (outgoing)

To delegate a subdomain such as blog.example.com, tell DNS resolvers where to find the zone file:

1. Log in to the Cloudflare dashboard ↗ and select your account.

2. Select the domain that contains the subdomain to be delegated.

3. Go to the DNS Records page.

   Go to Records

4. Create NS records for the subdomain. For example:

   • blog.example.com NS ns1.externalhost.com
   • blog.example.com NS ns2.externalhost.com
   • blog.example.com NS ns3.externalhost.com

   Note

   The A records for the subdomain are only required as glue records for nameservers that are located in the subdomain of the current zone that is being delegated.

5. (Optional) If the delegated nameserver has DNSSEC enabled, add the DS record in Cloudflare.

Limits

When creating NS records, there are limits on the number of nameservers that can be associated with a single delegation name.

According to DNS standards defined in RFC 1912 ↗, a delegation should not include more than seven nameserver names for the same delegation name.

To align with these standards and maintain platform stability:

• Cloudflare supports up to 10 NS records per delegation name, but the best practice is to keep the set at seven or fewer.
• Creating more than 10 NS records for the same name is not supported. Requests that exceed this limit may be rejected or fail validation.

Example

DNS management for example.com:

Type	Name	Content
NS	blog	ns1.externalhost.com
NS	blog	ns2.externalhost.com
NS	blog	ns3.externalhost.com
NS	blog	ns4.externalhost.com
NS	blog	ns5.externalhost.com
NS	blog	ns6.externalhost.com
NS	blog	ns7.externalhost.com
NS	blog	ns8.externalhost.com
NS	blog	ns9.externalhost.com
NS	blog	ns10.externalhost.com

In this example, Cloudflare would prevent you from adding another NS record for the delegation name blog.

Delegate a subdomain (incoming)

To delegate a subdomain from an external DNS provider to Cloudflare, refer to subdomain setups.