Resolvers

DNS Negative Caching Keeps Failed Lookups Temporary

A DNS lookup does not always return an address or another requested record. An authoritative server can report that a domain name does not exist, or it can report that the name exists but has no record of the requested type. Recursive resolvers can keep these negative answers in cache for a limited period. That behavior reduces repeated traffic for the same failed lookup and prevents authoritative servers from receiving identical questions on every client attempt.