Populating resolvers with the root zone

DNS recursive resolver operators need to provide the best service possible for their users, which includes providing an operationally robust and privacy protecting service. Challenges to these deployment goals include difficulty of getting responses from the root servers (such as during a network attack), longer-than-desired round-trip times to the closest DNS root server, and privacy issues relating to queries sent to the DNS root servers. Resolvers can solve all of these issues by simply serving an already cached a copy of the full root zone. This document shows how resolvers can fetch, cache and maintain a copy of the root zone, how to detect if the contents becomes stale, and procedures for handling error conditions.