Quick Answer
The correct answer is NTPv4 autokey authentication, as it provides the most secure method for authenticating NTP associations in a service provider network. NTPv4 autokey uses public key cryptography to automatically generate and exchange session keys, eliminating the need for manual key distribution and offering stronger protection against spoofing and replay attacks compared to older methods. On the Cisco SPCOR 350-501 exam, this question tests your understanding of NTP security best practices, often presenting NTPv3 symmetric keys or MD5 as distractors because they are simpler but less secure. A common trap is assuming MD5 is acceptable for modern networks, but the exam emphasizes that NTPv4 autokey is the recommended standard for cryptographic authentication. Remember the mnemonic: “Auto-key for auto-security” — if you see autokey in the options, it’s the most secure and correct choice for NTPv4.
This 350-501 practice question tests your understanding of architecture. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 SP network uses NTP for synchronization. To secure NTP, which authentication mode should be used?
NTPv4 autokey
NTPv4 autokey provides strong cryptographic authentication.
NTPv3 symmetric key
Why wrong: NTPv3 symmetric key is less secure and not recommended.
NTPv4 with SHA-1
Why wrong: SHA-1 is not standard for NTP authentication.
NTPv4 with MD5
Why wrong: MD5 is not recommended due to vulnerabilities.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
NTPv4 autokey
NTPv4 autokey provides cryptographic authentication and is recommended. Option A: NTPv3 symmetric key is less secure; Option C: MD5 is outdated; Option D: SHA-1 is not standard for NTP. Thus B is correct.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
NTPv4 autokey
Why this is correct
NTPv4 autokey provides strong cryptographic authentication.
Related concept
Read the scenario before looking for a memorised answer.
NTPv3 symmetric key
Why it's wrong here
NTPv3 symmetric key is less secure and not recommended.
NTPv4 with SHA-1
Why it's wrong here
SHA-1 is not standard for NTP authentication.
NTPv4 with MD5
Why it's wrong here
MD5 is not recommended due to vulnerabilities.
Common exam traps
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the 350-501 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Identify which 350-501 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Architecture — study guide chapter
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Architecture practice questions
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Cisco SPCOR / CCNP Service Provider Core 350-501 study guide
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FAQ
Architecture — This question tests Architecture — Read the scenario before looking for a memorised answer..
The correct answer is: NTPv4 autokey — NTPv4 autokey provides cryptographic authentication and is recommended. Option A: NTPv3 symmetric key is less secure; Option C: MD5 is outdated; Option D: SHA-1 is not standard for NTP. Thus B is correct.
Identify which 350-501 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jun 24, 2026
This 350-501 practice question is part of Courseiva's free Cisco 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 350-501 exam.
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