Which DNS application profile setting returns NOERROR responses for IPv6 AAAA queries when there is no AAAA record present for the FQDN?

Question

Options

• AChange "Invalid DNS Query Processing" to drop
• BChange "Number of IPs returned by DNS server" to 4
• CAdd an IPv6 domain name to "Valid Subdomains"
• DChange "Invalid DNS Query Processing" to respond

• A
  13% (4)
• B
  6% (2)
• C
  3% (1)
• D
  78% (25)

Explanation

Option D is correct because "Invalid DNS Query Processing: Respond" instructs the DNS application profile to send a NOERROR response (with an empty answer section) when a AAAA query is made for an FQDN that has no AAAA record - this is the standard RFC-compliant behavior that prevents clients from retrying or failing unnecessarily.

• Option A (Drop) is the opposite behavior: dropping the query causes the client to time out and retry, which degrades performance and does not return NOERROR.
• Option B (Number of IPs returned) controls how many A/AAAA records are included in a valid response, not how invalid or missing-record queries are handled.
• Option C (Valid Subdomains) governs which domain names are considered legitimate targets for the profile, unrelated to how the server responds to missing record types.

Memory tip: Think of it as "Respond politely to bad questions." When a client asks for an IPv6 address that doesn't exist, you respond with NOERROR (graceful empty answer) rather than dropping the question and leaving the client waiting - "Respond = Respond gracefully."

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