CompTIA Network+ N10-009 Exam 2026 – 190 Practice Questions
with Answers & Detailed Rationales, Network Infrastructure, IP
Addressing, Network Operations, Security, Troubleshooting &
Performance Optimization
DOMAIN 1: NETWORKING CONCEPTS (23% — Questions 1–44)
Question 1
Which OSI model layer is responsible for logical addressing and path determination?
A. Data Link Layer
B. Network Layer
C. Transport Layer
D. Session Layer
Correct Answer: B
Explanation: Layer 3 (Network) handles logical addressing (IP addresses) and routing
decisions, enabling packets to traverse multiple networks to reach their destination.
Question 2
A network technician needs to connect a workstation to a switch using a cable that supports
10 Gbps over distances up to 100 meters. Which cable type is most appropriate?
A. Cat 5e
B. Cat 6a
,C. Single-mode fiber
D. Coaxial
Correct Answer: B
Explanation: Cat 6a supports 10GBASE-T up to 100 meters and is designed for 10 Gbps
Ethernet, unlike Cat 5e which limits 10 Gbps to shorter runs.
Question 3
Which protocol operates at the Transport Layer and provides reliable, connection-oriented
data delivery?
A. UDP
B. ICMP
C. TCP
D. ARP
Correct Answer: C
Explanation: TCP (Transmission Control Protocol) uses a three-way handshake and
acknowledgments to guarantee ordered, reliable delivery, while UDP is connectionless and
best-effort.
Question 4
A network administrator is configuring a subnet for a branch office that requires 50 usable
host addresses. Which CIDR notation provides the appropriate number of usable addresses?
,A. /25
B. /26
C. /27
D. /28
Correct Answer: B
Explanation: A /26 subnet has 6 host bits, yielding 64 total addresses and 62 usable host
addresses, which accommodates 50 hosts with room for growth.
Question 5
Which cloud deployment model provides shared infrastructure to multiple organizations
while maintaining logical isolation?
A. Private cloud
B. Community cloud
C. Public cloud
D. Hybrid cloud
Correct Answer: C
Explanation: Public cloud services (AWS, Azure, GCP) share physical infrastructure among
tenants but use logical isolation (VPCs, security groups) to separate customer environments.
Question 6
What is the primary purpose of the Address Resolution Protocol (ARP)?
, A. Resolve IPv6 addresses to MAC addresses
B. Resolve IPv4 addresses to MAC addresses
C. Resolve hostnames to IP addresses
D. Resolve MAC addresses to port numbers
Correct Answer: B
Explanation: ARP maps known IPv4 addresses to unknown MAC addresses on the local
segment, allowing frames to be properly addressed at Layer 2.
Question 7
Which type of network topology provides the highest level of redundancy but requires the
most cabling?
A. Star
B. Mesh
C. Bus
D. Ring
Correct Answer: B
Explanation: A full mesh topology connects every node to every other node, providing
maximum redundancy and fault tolerance at the cost of extensive cabling and complexity.
Question 8
A technician discovers a device with IP address 169.254.12.45. What does this address
indicate?
with Answers & Detailed Rationales, Network Infrastructure, IP
Addressing, Network Operations, Security, Troubleshooting &
Performance Optimization
DOMAIN 1: NETWORKING CONCEPTS (23% — Questions 1–44)
Question 1
Which OSI model layer is responsible for logical addressing and path determination?
A. Data Link Layer
B. Network Layer
C. Transport Layer
D. Session Layer
Correct Answer: B
Explanation: Layer 3 (Network) handles logical addressing (IP addresses) and routing
decisions, enabling packets to traverse multiple networks to reach their destination.
Question 2
A network technician needs to connect a workstation to a switch using a cable that supports
10 Gbps over distances up to 100 meters. Which cable type is most appropriate?
A. Cat 5e
B. Cat 6a
,C. Single-mode fiber
D. Coaxial
Correct Answer: B
Explanation: Cat 6a supports 10GBASE-T up to 100 meters and is designed for 10 Gbps
Ethernet, unlike Cat 5e which limits 10 Gbps to shorter runs.
Question 3
Which protocol operates at the Transport Layer and provides reliable, connection-oriented
data delivery?
A. UDP
B. ICMP
C. TCP
D. ARP
Correct Answer: C
Explanation: TCP (Transmission Control Protocol) uses a three-way handshake and
acknowledgments to guarantee ordered, reliable delivery, while UDP is connectionless and
best-effort.
Question 4
A network administrator is configuring a subnet for a branch office that requires 50 usable
host addresses. Which CIDR notation provides the appropriate number of usable addresses?
,A. /25
B. /26
C. /27
D. /28
Correct Answer: B
Explanation: A /26 subnet has 6 host bits, yielding 64 total addresses and 62 usable host
addresses, which accommodates 50 hosts with room for growth.
Question 5
Which cloud deployment model provides shared infrastructure to multiple organizations
while maintaining logical isolation?
A. Private cloud
B. Community cloud
C. Public cloud
D. Hybrid cloud
Correct Answer: C
Explanation: Public cloud services (AWS, Azure, GCP) share physical infrastructure among
tenants but use logical isolation (VPCs, security groups) to separate customer environments.
Question 6
What is the primary purpose of the Address Resolution Protocol (ARP)?
, A. Resolve IPv6 addresses to MAC addresses
B. Resolve IPv4 addresses to MAC addresses
C. Resolve hostnames to IP addresses
D. Resolve MAC addresses to port numbers
Correct Answer: B
Explanation: ARP maps known IPv4 addresses to unknown MAC addresses on the local
segment, allowing frames to be properly addressed at Layer 2.
Question 7
Which type of network topology provides the highest level of redundancy but requires the
most cabling?
A. Star
B. Mesh
C. Bus
D. Ring
Correct Answer: B
Explanation: A full mesh topology connects every node to every other node, providing
maximum redundancy and fault tolerance at the cost of extensive cabling and complexity.
Question 8
A technician discovers a device with IP address 169.254.12.45. What does this address
indicate?
