According to theDesigning and Implementing Enterprise Network Assurance (300-445 ENNA)curriculum, DNS testing is a fundamental component of ensuring application availability and performance. The ThousandEyes platform provides two primary types of DNS tests:DNS ServerandDNS Trace.

To satisfy the specific requirements of monitoringIPv6 recordsandname server resolution times, the engineer must utilize theDNS Server test. This test type is designed to measure the performance of specific DNS servers by querying them for particular resource records.

Monitoring IPv6 Records:In the DNS system, IPv6 address records are known asAAAA records. Therefore, to monitor the availability and resolution of IPv6 addresses for a domain, the engineer must create a DNS Server test and set the query type toAAAA(Option B).

Monitoring Name Server Resolution Times:To measure how long it takes for a DNS server to return the authoritative name servers for a domain, the engineer must query forNS (Name Server) records. By creating a DNS Server test targeting theNS record(Option D), the platform can provide granular metrics on the response time and availability of those specific records from the perspective of the selected agents.

DNS Trace tests(Options C and E) are less suitable for measuring specific resolutiontimesof a single server; instead, they are used to visualize the entire delegation path from the root servers down to the authoritative servers to identify where a "break" in the chain occurs. Furthermore, anA recordquery (Option A) only provides the IPv4 address, failing the requirement to monitor IPv6. By selectingDNS Servertests forAAAAandNSrecords, the administrator ensures they have the precise performance data needed to baseline and troubleshoot the organization's DNS health.