NSE4 Question #547: Real Exam Question with Answer & Explanation

Question

What statement describes what DNS64 does?

Options

• AConverts DNS A record lookups to AAAA record lookups.
• BTranslates the destination IPv6 address of the DNS traffic to an IPv4 address.
• CSynthesizes DNS AAAA records from A records.
• DTranslates the destination IPv4 address of the DNS traffic to an IPv6 address.

Explanation

DNS64 is a mechanism that, in conjunction with NAT64, allows IPv6-only clients to communicate with IPv4-only servers by enabling the translation of destination IPv6 addresses to IPv4 addresses.

Common mistakes.

• A. DNS64 does not convert A record lookups; it provides an AAAA record response when only an A record exists for a name.
• C. While DNS64 does synthesize AAAA records from A records, this statement describes a specific internal mechanism rather than the broader network-level translation outcome that is enabled through its cooperation with NAT64 for data traffic.
• D. DNS64 and NAT64 facilitate translation from IPv6 to IPv4 for communication with IPv4-only hosts, not the translation of an IPv4 destination to an IPv6 address for the purpose of reaching IPv4-only destinations.

Concept tested. DNS64 and NAT64 IPv6-IPv4 translation

Reference. https://learn.microsoft.com/en-us/windows-server/networking/dns/dns64-nat64-deployment

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