DNS delegation

DNS delegation is the process of assigning responsibility for part of DNS to another set of name servers that publish its official records. The parent zone, the part of DNS above it, publishes information directing DNS lookup services (resolvers) to the servers responsible for the child zone.

How does a delegation work?

Suppose example.com is managed in one DNS zone and its owner wants a separate team to manage shop.example.com. The parent zone publishes NS records for shop.example.com that name the child zone's authoritative servers. Queries for names inside that child zone can then be answered by those servers, while the parent continues to answer for the rest of example.com.

If a name server's hostname is inside the child zone it serves, the parent may also need address information called glue to help resolvers reach it without a circular lookup. The exact records needed depend on the nameserver names and delegation setup.

Delegation changes who serves DNS data for a name and the names below it. It does not transfer ownership of the registered domain or automatically move website hosting or email. The child zone must also be configured on the delegated servers; otherwise, resolvers may reach them but receive errors or incomplete answers.

Related terms

• DNS zone — the part of the DNS naming system being served
• Nameserver — the server named by a delegation
• NS record — publishes the delegated server names
• Domain registration — a separate administrative system