WGU C172 – Network and Security Foundations
(2026 Edition) PA & OA Comprehensive Practice
Exam 150 Realistic Questions with Verified
Answers & Detailed Explanations| Instant Pdf
Download
INTRODUCTION
This study guide is a comprehensive practice resource designed specifically for Western Governors
University (WGU) C172 – Network and Security Foundations. It is fully aligned with the 2026 Program
Assessment (PA) and Objective Assessment (OA) competencies and reflects the style, depth, and
difficulty of the actual WGU exam.
The guide contains 150 original, exam-style multiple-choice questions, carefully structured to reinforce
both conceptual understanding and scenario-based reasoning required to pass the OA on the first
attempt. Each question includes a verified correct answer and a clear, concise explanation to ensure
mastery of key networking and security principles.
What This Guide Covers
OSI & TCP/IP Models
Network Devices, Topologies, and Media
IP Addressing, Subnetting, and Routing
Network Protocols and Services
Security Fundamentals & CIA Triad
Threats, Attacks, and Vulnerabilities
Authentication, Authorization & Access Control
Cryptography & PKI Basics
Network Defense Technologies
Risk Management, Policies, and Business Continuit
,DOMAIN 1: NETWORK MODELS & CONCEPTS
Q1. Which OSI layer is responsible for encryption and data formatting?
A. Application
B. Presentation
C. Session
D. Transport
✅ Answer: B. Presentation
Explanation: The Presentation layer formats data, handles encryption/decryption, and
compression so systems can interpret data correctly.
Q2. Which layer of the OSI model establishes, manages, and terminates
communication sessions?
A. Network
B. Transport
C. Session
D. Presentation
✅ Answer: C. Session
Explanation: The Session layer controls session setup, maintenance, and termination between
devices.
Q3. What protocol resolves an IP address to a MAC address?
A. DNS
B. ARP
C. DHCP
D. ICMP
✅ Answer: B. ARP
Explanation: ARP maps logical IP addresses to physical MAC addresses on a local network.
Q4. Which protocol is primarily used to test connectivity?
A. SNMP
B. FTP
,C. ICMP
D. SMTP
✅ Answer: C. ICMP
Explanation: ICMP is used by tools like ping to test reachability and network health.
Q5. Which OSI layer is responsible for routing packets?
A. Data Link
B. Transport
C. Network
D. Application
✅ Answer: C. Network
Explanation: The Network layer determines the best path for data across networks.
Q6. What does TCP provide that UDP does not?
A. Speed
B. Broadcasting
C. Reliability
D. Multicasting
✅ Answer: C. Reliability
Explanation: TCP ensures data delivery, sequencing, and error correction, unlike UDP.
Q7. Which port is used by HTTPS?
A. 80
B. 21
C. 443
D. 110
✅ Answer: C. 443
Explanation: HTTPS uses port 443 for encrypted web communication.
Q8. Which device forwards traffic based on MAC addresses?
, A. Router
B. Firewall
C. Switch
D. Gateway
✅ Answer: C. Switch
Explanation: Switches operate at Layer 2 and forward frames using MAC addresses.
Q9. Which protocol automatically assigns IP addresses?
A. DNS
B. ARP
C. DHCP
D. SNMP
✅ Answer: C. DHCP
Explanation: DHCP dynamically assigns IP addresses and network configuration settings.
Q10. Which OSI layer handles error detection and correction?
A. Transport
B. Data Link
C. Network
D. Physical
✅ Answer: A. Transport
Explanation: The Transport layer ensures reliable data transmission and error recovery.
DOMAIN 2: NETWORK TOPOLOGIES & MEDIA
Q11. Which topology has a single point of failure?
A. Mesh
B. Ring
C. Star
D. Hybrid
✅ Answer: C. Star
Explanation: Failure of the central hub or switch disrupts all connected devices.
(2026 Edition) PA & OA Comprehensive Practice
Exam 150 Realistic Questions with Verified
Answers & Detailed Explanations| Instant Pdf
Download
INTRODUCTION
This study guide is a comprehensive practice resource designed specifically for Western Governors
University (WGU) C172 – Network and Security Foundations. It is fully aligned with the 2026 Program
Assessment (PA) and Objective Assessment (OA) competencies and reflects the style, depth, and
difficulty of the actual WGU exam.
The guide contains 150 original, exam-style multiple-choice questions, carefully structured to reinforce
both conceptual understanding and scenario-based reasoning required to pass the OA on the first
attempt. Each question includes a verified correct answer and a clear, concise explanation to ensure
mastery of key networking and security principles.
What This Guide Covers
OSI & TCP/IP Models
Network Devices, Topologies, and Media
IP Addressing, Subnetting, and Routing
Network Protocols and Services
Security Fundamentals & CIA Triad
Threats, Attacks, and Vulnerabilities
Authentication, Authorization & Access Control
Cryptography & PKI Basics
Network Defense Technologies
Risk Management, Policies, and Business Continuit
,DOMAIN 1: NETWORK MODELS & CONCEPTS
Q1. Which OSI layer is responsible for encryption and data formatting?
A. Application
B. Presentation
C. Session
D. Transport
✅ Answer: B. Presentation
Explanation: The Presentation layer formats data, handles encryption/decryption, and
compression so systems can interpret data correctly.
Q2. Which layer of the OSI model establishes, manages, and terminates
communication sessions?
A. Network
B. Transport
C. Session
D. Presentation
✅ Answer: C. Session
Explanation: The Session layer controls session setup, maintenance, and termination between
devices.
Q3. What protocol resolves an IP address to a MAC address?
A. DNS
B. ARP
C. DHCP
D. ICMP
✅ Answer: B. ARP
Explanation: ARP maps logical IP addresses to physical MAC addresses on a local network.
Q4. Which protocol is primarily used to test connectivity?
A. SNMP
B. FTP
,C. ICMP
D. SMTP
✅ Answer: C. ICMP
Explanation: ICMP is used by tools like ping to test reachability and network health.
Q5. Which OSI layer is responsible for routing packets?
A. Data Link
B. Transport
C. Network
D. Application
✅ Answer: C. Network
Explanation: The Network layer determines the best path for data across networks.
Q6. What does TCP provide that UDP does not?
A. Speed
B. Broadcasting
C. Reliability
D. Multicasting
✅ Answer: C. Reliability
Explanation: TCP ensures data delivery, sequencing, and error correction, unlike UDP.
Q7. Which port is used by HTTPS?
A. 80
B. 21
C. 443
D. 110
✅ Answer: C. 443
Explanation: HTTPS uses port 443 for encrypted web communication.
Q8. Which device forwards traffic based on MAC addresses?
, A. Router
B. Firewall
C. Switch
D. Gateway
✅ Answer: C. Switch
Explanation: Switches operate at Layer 2 and forward frames using MAC addresses.
Q9. Which protocol automatically assigns IP addresses?
A. DNS
B. ARP
C. DHCP
D. SNMP
✅ Answer: C. DHCP
Explanation: DHCP dynamically assigns IP addresses and network configuration settings.
Q10. Which OSI layer handles error detection and correction?
A. Transport
B. Data Link
C. Network
D. Physical
✅ Answer: A. Transport
Explanation: The Transport layer ensures reliable data transmission and error recovery.
DOMAIN 2: NETWORK TOPOLOGIES & MEDIA
Q11. Which topology has a single point of failure?
A. Mesh
B. Ring
C. Star
D. Hybrid
✅ Answer: C. Star
Explanation: Failure of the central hub or switch disrupts all connected devices.
