easyMultiple ChoiceObjective-mapped
220-1201 Practice Question: That their computer's clock is consistently off…
A user reports that their computer's clock is consistently off by several minutes, causing authentication failures with the domain. The network uses Active Directory. Which service should be checked first?
⚠ Common exam trap
It's easy for candidates to confuse time synchronization with DHCP or DNS, assuming those services handle all network configuration, but NTP is the root cause for Kerberos authentication failures due to time skew.
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
NTP (Network Time Protocol) is the correct service to check first because the symptom—a clock consistently off by several minutes causing authentication failures with an Active Directory domain—is a classic sign of time synchronization issues. Active Directory uses Kerberos for authentication, which requires the client and domain controller clocks to be within a default skew of 5 minutes (RFC 4120). If the time is off, Kerberos tickets are rejected, leading to authentication failures.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
DHCP
Why it's wrong here
DHCP assigns IP addresses, not time.
- ✗
DNS
Why it's wrong here
DNS resolves names, not time.
- ✓
NTP
Why this is correct
NTP synchronizes system clocks, preventing time-related authentication issues.
- ✗
RADIUS
Why it's wrong here
RADIUS provides authentication but doesn't manage time.
Go deeper
Related to this question
Learn chapter
Network Configuration: IP, DNS, DHCP
Key term
Synchronization
Synchronization is the process of making sure two or more systems, devices, or pieces of data stay exactly matched and up-to-date with each other.
Key term
Precision Time Protocol
Precision Time Protocol is a network protocol used to synchronize clocks across devices with extremely high accuracy, often within microseconds or nanoseconds.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1201 practice question is part of Courseiva's free CompTIA 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 220-1201 exam.