The top of the Domain Name Systemⁱ (DNSⁱ) hierarchy. Often referred to as the "dot" or the "root zone file". The root zone file contains authoritative data on the registries for all the top-level domains , that is, the root servers know which name servers contain authoritative data for the generic top level domains, e.g., .com, and .net, as well as the country code domains, e.g., ,fr and ,uk. The content of the root zone file is currently controlled by the NTIAⁱ (q.v.).