350-501 Security and Services Practice Question
An engineer wants to secure NTP on IOS XR routers. Which configuration is required to prevent unauthorized time synchronization?
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
✓
NTP authentication with a key
NTP authentication using a key ensures that only trusted NTP servers can update the router's clock, preventing spoofing attacks.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
NTP broadcast mode
Why it's wrong here
Broadcast mode is less secure and doesn't authenticate.
- ✗
NTP access group with ACL
Why it's wrong here
Access group limits which peers can query, but does not authenticate.
- ✗
NTP version 4 only
Why it's wrong here
Version alone doesn't provide security.
- ✓
NTP authentication with a key
Why this is correct
NTP authentication validates the source using a shared key.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.