DNS delegation is the process of assigning authority for a specific subdomain to a different DNS server or set of DNS servers. This allows for the management of different parts of a domain’s namespace by different entities or organizations. DNS delegation is commonly used to distribute the responsibility of managing subdomains while maintaining the overall control of the main domain.

When a domain is delegated, it involves creating NS (Name Server) records in the parent domain’s DNS zone that point to the DNS servers responsible for handling the DNS records for the delegated subdomain. Here’s how DNS delegation works:

  1. Parent Domain Authority:
    The parent domain (e.g., example.com) holds authority over the entire domain. This domain’s DNS server contains the information about the delegated subdomain and the DNS servers responsible for it.
  2. Subdomain Delegation:
    Let’s say you want to delegate the subdomain sub.example.com to another DNS server. To do this, you would create NS records in the DNS zone for example.com. These NS records would specify the names of the DNS servers responsible for handling queries for sub.example.com.
  3. Subdomain’s DNS Servers:
    The DNS servers specified in the NS records for sub.example.com become authoritative for that subdomain. They maintain the DNS records (A, MX, CNAME, etc.) specific to sub.example.com. Queries for sub.example.com are directed to these DNS servers.
  4. Delegated Subdomain Records:
    The delegated DNS servers for sub.example.com are responsible for managing the DNS records within that subdomain. This could include creating and updating records like A records (for IP addresses), MX records (for email servers), and more.

DNS delegation allows different parties to manage their own DNS records independently. This is often useful for scenarios such as hosting services on a specific subdomain (e.g., mail.example.com for email services) or delegating control of certain parts of a domain to subsidiaries or partner organizations.

It’s important to note that DNS delegation should be configured carefully to ensure proper resolution of DNS queries. Inaccurate delegation settings or misconfigured DNS records can lead to DNS resolution issues and affect the availability of services associated with the delegated subdomain.