DNS/RFC/8109について、ここに記述してください。
https://tools.ietf.org/html/rfc8109
BEST CURRENT PRACTICE Internet Engineering Task Force (IETF) P. Koch Request for Comments: 8109 DENIC eG BCP: 209 M. Larson Category: Best Current Practice P. Hoffman ISSN: 2070-1721 ICANN March 2017 Initializing a DNS Resolver with Priming Queries Abstract This document describes the queries that a DNS resolver should emit to initialize its cache. The result is that the resolver gets both a current NS Resource Record Set (RRset) for the root zone and the necessary address information for reaching the root servers.
3.1. Repeating Priming Queries
- The recursive resolver SHOULD send a priming query only when it is needed, such as when the resolver starts with an empty cache and when the NS RRset for the root zone has expired. Because the NS records for the root are not special, the recursive resolver expires those NS records according to their TTL values. (Note that a recursive resolver MAY pre-fetch the NS RRset before it expires.)