DNS on Windows Server 2003, 3rd Edition

On Registrars and Registries

Before we go any further, we need to define a few terms: registry, registrar, and registration. These terms aren’t defined anywhere in the DNS specs. Instead, they apply to the way the Internet namespace is managed today.

A registry is an organization responsible for maintaining a top-level domain’s (well, zone’s, really) datafiles, which contain the delegation to each subdomain of that top-level domain. Under the current structure of the Internet, a given top-level domain can have no more than one registry.

A registrar acts as an interface between customers and the registry, providing registration and value-added services. It submits to the registry the zone data and other data (including contact information) for each of its customers in a single top-level domain.

Registration is the process by which a customer tells a registrar which name servers to delegate a subdomain to and provides the registrar with contact and billing information. The registrar makes these changes through the registry.

To give you some concrete examples of how this works in the real world, Public Interest Registry runs the org registry. VeriSign, Inc. currently acts as the registry for the com and net top-level domains. There are dozens of registrars for com, net, and org, including Network Solutions—a former subsidiary of VeriSign. An organization called EDUCAUSE runs the edu registry and is its only registrar. But before we get too off-track, let’s get back to our story. ...