WGU D412 NETWORK ANALYTICS &
TROUBLESHOOTING — 320 PRACTICE EXAM
QUESTIONS AND CORRECT ANSWERS WITH
RATIONALES
WGU D412 equips students with practical network analytics and troubleshooting
skills essential for modern IT roles. The course emphasizes a structured, layered
diagnostic methodology, primarily following the OSI model to systematically isolate
faults—starting with physical layer checks and progressing to application-level
analysis. Students master critical command-line tools (ping, tracert, ipconfig, netstat,
lookup) and protocol analyzers like Wireshark to capture and interpret live traffic.
The curriculum focuses heavily on core network services: diagnosing DHCP failures,
resolving DNS misconfigurations (such as malicious forward lookup zones), and
analyzing IP addressing and subnetting. Lab scenarios simulate real-world outages,
requiring root cause analysis and proper documentation. Additionally, students
learn to utilize performance monitors and telemetry data to baseline network
behavior. Ultimately, the course aims to develop proficient problem-solvers who can
efficiently restore connectivity, ensuring network resilience while adhering to security
standards and disaster recovery best practices in complex environments. (120
words)
Questions 1–50: OSI Model & Networking Fundamentals
1. Which OSI layer is responsible for organizing how bits are passed over the
physical layer between devices within the same collision domain?
,A. Frame
B. Connection
C. Transport
D. Data Link
Answer: D — The Data Link Layer (Layer 2) organizes bits into frames and
manages access to the physical medium within the same collision domain.
2. Which OSI layer would define the scope of a protocol that makes sure packets
of data are received correctly and resends them if they are not?
A. Validation
B. Transmission
C. Transport
D. Connection
Answer: C — The Transport Layer (Layer 4) provides reliable data delivery, error
recovery, and retransmission of lost packets.
3. Which protocol suite performs functions of OSI layer 4?
A. IPX
B. MAC
C. CSMA/CD
D. TCP
Answer: D — TCP operates at the Transport Layer, providing connectionoriented,
reliable communication.
4. What are the 7 layers of the OSI model in correct order from top to bottom?
,A. Physical, Data Link, Network, Transport, Session, Presentation, Application
B. Application, Presentation, Session, Transport, Network, Data Link, Physical
C. Application, Transport, Network, Data Link, Physical, Session, Presentation
D. Physical, Data Link, Network, Transport, Session, Presentation, Application
Answer: B — The OSI model layers from top (Layer 7) to bottom (Layer 1) are:
Application, Presentation, Session, Transport, Network, Data Link, Physical.
5. Which OSI layer manages communication sessions between applications?
A. Application Layer
B. Presentation Layer
C. Session Layer
D. Transport Layer
Answer: C — The Session Layer (Layer 5) establishes, manages, and terminates
communication sessions between applications.
6. Which OSI layer uses port numbers in its addressing?
A. Data Link Layer
B. Network Layer
C. Transport Layer
D. Application Layer
Answer: C — The Transport Layer uses port numbers (0–65535) to identify specific
applications or services.
7. The MAC table and ARP table are associated with which OSI layers?
, A. MAC table — Network Layer; ARP table — Data Link Layer
B. MAC table — Data Link Layer; ARP table — Network Layer
C. Both operate at the Physical Layer
D. Both operate at the Transport Layer
Answer: B — Switches use MAC tables at Layer 2 (Data Link) to forward frames.
ARP tables map IP addresses to MAC addresses at Layer 3 (Network).
8. Which layer of the OSI model handles routing between networks?
A. Physical Layer
B. Data Link Layer
C. Network Layer
D. Transport Layer
Answer: C — The Network Layer (Layer 3) is responsible for logical addressing and
routing between different networks.
9. Which of the following is a connectionless protocol?
A. TCP
B. UDP
C. HTTP
D. FTP
Answer: B — UDP does not establish a session before transmitting data, making it
connectionless.
10. What is the main purpose of DNS in a network?
TROUBLESHOOTING — 320 PRACTICE EXAM
QUESTIONS AND CORRECT ANSWERS WITH
RATIONALES
WGU D412 equips students with practical network analytics and troubleshooting
skills essential for modern IT roles. The course emphasizes a structured, layered
diagnostic methodology, primarily following the OSI model to systematically isolate
faults—starting with physical layer checks and progressing to application-level
analysis. Students master critical command-line tools (ping, tracert, ipconfig, netstat,
lookup) and protocol analyzers like Wireshark to capture and interpret live traffic.
The curriculum focuses heavily on core network services: diagnosing DHCP failures,
resolving DNS misconfigurations (such as malicious forward lookup zones), and
analyzing IP addressing and subnetting. Lab scenarios simulate real-world outages,
requiring root cause analysis and proper documentation. Additionally, students
learn to utilize performance monitors and telemetry data to baseline network
behavior. Ultimately, the course aims to develop proficient problem-solvers who can
efficiently restore connectivity, ensuring network resilience while adhering to security
standards and disaster recovery best practices in complex environments. (120
words)
Questions 1–50: OSI Model & Networking Fundamentals
1. Which OSI layer is responsible for organizing how bits are passed over the
physical layer between devices within the same collision domain?
,A. Frame
B. Connection
C. Transport
D. Data Link
Answer: D — The Data Link Layer (Layer 2) organizes bits into frames and
manages access to the physical medium within the same collision domain.
2. Which OSI layer would define the scope of a protocol that makes sure packets
of data are received correctly and resends them if they are not?
A. Validation
B. Transmission
C. Transport
D. Connection
Answer: C — The Transport Layer (Layer 4) provides reliable data delivery, error
recovery, and retransmission of lost packets.
3. Which protocol suite performs functions of OSI layer 4?
A. IPX
B. MAC
C. CSMA/CD
D. TCP
Answer: D — TCP operates at the Transport Layer, providing connectionoriented,
reliable communication.
4. What are the 7 layers of the OSI model in correct order from top to bottom?
,A. Physical, Data Link, Network, Transport, Session, Presentation, Application
B. Application, Presentation, Session, Transport, Network, Data Link, Physical
C. Application, Transport, Network, Data Link, Physical, Session, Presentation
D. Physical, Data Link, Network, Transport, Session, Presentation, Application
Answer: B — The OSI model layers from top (Layer 7) to bottom (Layer 1) are:
Application, Presentation, Session, Transport, Network, Data Link, Physical.
5. Which OSI layer manages communication sessions between applications?
A. Application Layer
B. Presentation Layer
C. Session Layer
D. Transport Layer
Answer: C — The Session Layer (Layer 5) establishes, manages, and terminates
communication sessions between applications.
6. Which OSI layer uses port numbers in its addressing?
A. Data Link Layer
B. Network Layer
C. Transport Layer
D. Application Layer
Answer: C — The Transport Layer uses port numbers (0–65535) to identify specific
applications or services.
7. The MAC table and ARP table are associated with which OSI layers?
, A. MAC table — Network Layer; ARP table — Data Link Layer
B. MAC table — Data Link Layer; ARP table — Network Layer
C. Both operate at the Physical Layer
D. Both operate at the Transport Layer
Answer: B — Switches use MAC tables at Layer 2 (Data Link) to forward frames.
ARP tables map IP addresses to MAC addresses at Layer 3 (Network).
8. Which layer of the OSI model handles routing between networks?
A. Physical Layer
B. Data Link Layer
C. Network Layer
D. Transport Layer
Answer: C — The Network Layer (Layer 3) is responsible for logical addressing and
routing between different networks.
9. Which of the following is a connectionless protocol?
A. TCP
B. UDP
C. HTTP
D. FTP
Answer: B — UDP does not establish a session before transmitting data, making it
connectionless.
10. What is the main purpose of DNS in a network?
