Using Custom DNS with "Subdomains"

Custom DNS is designed primarily to work with domains owned/registered by the customer (example.com, example.co.uk, etc). However, Custom DNS can also be used with individual subdomains (host.example.com, host.example.co.uk, etc). By delegating a single subdomain to Custom DNS, you can receive the benefits of our dynamic update system while leaving the rest of your domain's DNS unchanged.


Delegating a Subdomain

Delegating a single subdomain to Custom DNS is easy. Please follow these steps to perform the subdomain delegation:

  1. Create Custom DNS: Purchase Custom DNS for the subdomain itself, e.g. dynamic.example.com.
  2. Create NS records: In your current zone file for your domain at the other DNS provider, you will need to create NS (NameServer) records. These NS records "redirect" queries for the specific subdomain to Custom DNS. For dynamic.example.com, these records would look like:
dynamic.example.com.	48600	IN	NS	ns1.mydyndns.org.
dynamic.example.com.	48600	IN	NS	ns2.mydyndns.org.
dynamic.example.com.	48600	IN	NS	ns3.mydyndns.org.
dynamic.example.com.	48600	IN	NS	ns4.mydyndns.org.
dynamic.example.com.	48600	IN	NS	ns5.mydyndns.org.

Please note the trailing "." after each hostname.

Once these NS records have been created, queries for the subdomain will be answered by your Custom DNS zone. You can use our DNSCog reporting and analysis tools to check the delegation.