- A
Providing anonymous DNS resolution
Why wrong: DNSSEC does not provide anonymity.
- B
Authenticating the origin and ensuring integrity of DNS responses
DNSSEC uses digital signatures to validate the source and integrity of DNS data.
- C
Encrypting DNS queries to prevent eavesdropping
Why wrong: DNSSEC does not encrypt data; it only signs records.
- D
Blocking malicious DNS queries at the resolver
Why wrong: DNSSEC does not block queries; it validates responses.
Question 64 of 1,000
CISSP Communication and Network Security Practice Question
This CISSP practice question tests your understanding of communication and network security. Compare every option against the stated constraints before choosing — the best answer satisfies all requirements, not just the most obvious one. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
An organization is implementing DNSSEC to protect against DNS spoofing attacks. Which of the following best describes the primary security function provided by DNSSEC?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"best"Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Clue:
"primary"Why it matters: Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Authenticating the origin and ensuring integrity of DNS responses
DNSSEC (Domain Name System Security Extensions) provides data origin authentication and data integrity for DNS responses using digital signatures based on public-key cryptography. It does not encrypt DNS data or provide anonymity; instead, it allows a resolver to verify that a DNS response has not been modified in transit and that it originates from the authoritative source. This directly counters DNS spoofing attacks by ensuring the response is authentic and untampered.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Providing anonymous DNS resolution
Why it's wrong here
DNSSEC does not provide anonymity.
- ✓
Authenticating the origin and ensuring integrity of DNS responses
Why this is correct
DNSSEC uses digital signatures to validate the source and integrity of DNS data.
Clue confirmation
The clue words "best", "primary" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Encrypting DNS queries to prevent eavesdropping
Why it's wrong here
DNSSEC does not encrypt data; it only signs records.
- ✗
Blocking malicious DNS queries at the resolver
Why it's wrong here
DNSSEC does not block queries; it validates responses.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is confusing DNSSEC's authentication and integrity functions with encryption or anonymity, leading candidates to incorrectly select encryption (Option C) or anonymity (Option A) when DNSSEC explicitly does not provide confidentiality.
Detailed technical explanation
How to think about this question
DNSSEC works by adding Resource Record Signature (RRSIG) records to DNS zones, which are signed using the zone's private key. Resolvers validate these signatures using the corresponding public key published in DNSKEY records, following a chain of trust from the root zone (anchored by the root KSK) down to the target domain. A real-world scenario where this matters is in preventing cache poisoning attacks, such as the Kaminsky attack, where an attacker injects forged DNS responses; DNSSEC would cause the resolver to reject the forged records because the signature verification fails.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A developer is choosing between AES-256 (symmetric) and RSA-2048 (asymmetric) for encrypting a large file that will be sent to a partner. Symmetric encryption is fast but requires key exchange; asymmetric is slower but solves the key distribution problem. A hybrid approach — encrypt the file with AES, encrypt the AES key with RSA — is standard. Questions like this test whether you understand when each approach applies.
Visual reference
Quick reference
Asymmetric Encryption Algorithm Comparison
| Algorithm | Key Exchange | Signatures | Equivalent Security Key | Notes |
|---|---|---|---|---|
| RSA-3072 | Yes | Yes | 128-bit | Widely deployed; slow for bulk data |
| ECDSA P-256 | No | Yes | 128-bit | Fast signatures; standard TLS certs |
| ECDH / ECDHE | Yes | No | 128-bit | Perfect forward secrecy in TLS 1.3 |
| DH / DHE | Yes | No | 128-bit (3072-bit key) | Replaced by ECDHE in modern TLS |
| Ed25519 | No | Yes | ~128-bit | SSH keys, modern PKI |
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Questions learners often ask
What does this CISSP question test?
Communication and Network Security — This question tests Communication and Network Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Authenticating the origin and ensuring integrity of DNS responses — DNSSEC (Domain Name System Security Extensions) provides data origin authentication and data integrity for DNS responses using digital signatures based on public-key cryptography. It does not encrypt DNS data or provide anonymity; instead, it allows a resolver to verify that a DNS response has not been modified in transit and that it originates from the authoritative source. This directly counters DNS spoofing attacks by ensuring the response is authentic and untampered.
What should I do if I get this CISSP question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "best", "primary". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jul 4, 2026
This CISSP practice question is part of Courseiva's free ISC2 certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CISSP exam.
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