CyberCertPrepNetwork FundamentalsDNS & DHCPEASYFree question
Scenario
A DNS administrator notices that all DNS queries to the internal resolver for external domains (google.com, microsoft.com) are being answered within 2-5ms even on first query, while a fresh resolver in a lab takes 200-400ms for first queries.
What mechanism explains the production resolver's consistently fast response times for external domains?
- A.The production resolver has cached query results (both positive answers and referrals) for popular domains from previous client queries; DNS caching within the TTL means subsequent queries for the same name are answered from the local cache without iterating through the root-TLD-authoritative resolver chain again, reducing response time from 200-400ms to single-digit milliseconds
- B.The production resolver uses DNSSEC validation which pre-fetches all popular domain signatures; a DHCPOFFER is unicast to 255.255.255.255 with the client's new lease inside the DNS payload. DNSSEC encrypts query payloads end to end so resolvers cannot read them. The hosts file is consulted only after every configured DNS server has timed out