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Account custom nameservers

Account custom nameservers (ACNS) allow you to define account-level custom nameservers and use them for different zones within a Cloudflare account.

ACNS are organized in different sets (ns_set) and ACNS names can be provided by any domain, even if the domain does not exist as a zone in Cloudflare.

For instance, if the ACNS are and, the domains and are not required to be zones in Cloudflare.

​​ Configuration conditions

For this configuration to be possible, a few conditions apply:

  1. If the domain or domains that are used for the account custom nameservers do not exist within the same account, you must create the A/AAAA records on the configured nameserver names (e.g. at the authoritative DNS provider.
  1. You can create up to five different account custom nameserver sets. Each nameserver set must have between two and five different nameserver names (ns_name) and each name cannot belong to more than one set. For example, if is part of ns_set 1 it cannot be part of ns_set 2 or vice versa.
  2. Subdomain setup or Reverse zones can use account custom nameservers as long as they use a different nameserver set (ns_set) than their parent, child, or any other zone in their direct hierarchy tree.

​​ Add account custom nameservers

  1. Use the Add Account Custom Nameserver endpoint to create account custom nameservers. Follow the conditions for ns_name and ns_set.

  2. This step depends on whether you are using Cloudflare Registrar for the domain that provides the ACNS names:

  3. To enable the ACNS on existing zones, use the Set ACNS Related Zone Metadata endpoint on each zone. Cloudflare will assign an IPv4 and an IPv6 address to each ACNS name and automatically create the associated A or AAAA records.

    • If you are not using Cloudflare Registrar, also update the nameservers at your registrar to use the account custom nameserver names.

To make these ACNS the default nameservers for all new zones added to your account from now on, use the Update Account endpoint and set the value of default_nameservers to custom.account.

​​ Remove account custom nameservers

To remove ACNS and their associated DNS records from a zone: