C O M P T I A N E T W O R K+ C E R T I F I C A T I O N
EXAMINATION
NETWORK+
N10-009 EXAM
Real exam questions and verified answers, fully
aligned with the official CompTIA Network+ N10-009
objectives. 130 multiple-choice and performance-
based questions covering networking fundamentals,
implementations, operations, security, and
troubleshooting.
2026/2027 Edition | 100% Correct | Graded A+
Multiple-Choice & Performance-Based | Verified Answers
130 QUESTI ONS | 7 EXAM D OMAI NS | C OMPL ETE
C E RTI F I C ATI O N E X A M I N ATI O N
,COMPTIA NETWORK+ (N10-009) EXAM | 2026/2027 EDITION
Table of Contents
Section 1: Networking Fundamentals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Section 2: Network Implementations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Section 3: Network Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Section 4: Network Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Section 5: Network Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Section 6: Performance-Based Questions (PBQs) . . . . . . . . . . . . . . . . . . . . . . . . 33
Section 7: Mixed Comprehensive Scenarios & Case Studies . . . . . . . . . . . . . . . . . . . 40
Real Exam Questions and Verified Answers | Graded A+ 1
,COMPTIA NETWORK+ (N10-009) EXAM | 2026/2027 EDITION
Section 1: Networking Fundamentals
Q1. A network technician observes that a core router forwards packets between different IP subnets
based on logical addresses. At which OSI model layer does the router primarily operate?
A. Data Link layer, using MAC address tables
B. Transport layer, using TCP sequence numbers
C. Network layer, using logical IP addressing and routing tables [CORRECT]
D. Session layer, using dialog control tokens
Correct Answer: C
Rationale: The Network layer (Layer 3) is responsible for logical addressing (IP) and route selection
between networks, which is exactly the function a router performs. The Data Link layer (A) handles MAC
addressing and frames within a local segment, the Transport layer (B) manages end-to-end TCP/UDP
delivery, and the Session layer (D) manages dialog establishment between applications. (N10-009 Objective
1.1 - OSI model layers and functions)
Q2. A junior administrator is mapping the four-layer TCP/IP model to the seven-layer OSI model.
Which pair of OSI layers corresponds to the TCP/IP Network Access (Link) layer?
A. Physical and Data Link [CORRECT]
B. Application and Presentation
C. Session and Transport
D. Network and Transport
Correct Answer: A
Rationale: The TCP/IP Network Access (Link) layer combines the OSI Physical layer (cabling, signaling)
and the Data Link layer (MAC, frames). The TCP/IP Application layer (B) maps to OSI Layers 5 through 7,
and the Internet layer maps to OSI Layer 3 only. (N10-009 Objective 1.1 - OSI and TCP/IP model
comparison)
Q3. Users report that outbound email messages are stuck in the mail server queue. Firewall logs show
that outbound connections to remote mail exchangers are being blocked. Which protocol and port
combination is most likely being blocked?
A. SMTP on TCP 25 [CORRECT]
B. POP3 on TCP 110
C. IMAP on TCP 143
D. HTTPS on TCP 443
Correct Answer: A
Rationale: Simple Mail Transfer Protocol uses TCP port 25 for server-to-server mail relay, so blocking
outbound TCP 25 stops messages from leaving the queue. POP3 (B) and IMAP (C) are client retrieval
protocols, and HTTPS (D) is web traffic, none of which relay mail between servers. (N10-009 Objective 1.4
- Well-known ports and protocols)
Real Exam Questions and Verified Answers | Graded A+ 2
, COMPTIA NETWORK+ (N10-009) EXAM | 2026/2027 EDITION
Q4. A network engineer is calculating address space for a department and must use the 192.168.10.0/26
subnet. How many usable host addresses are available in this subnet?
A. 64 usable hosts
B. 30 usable hosts
C. 126 usable hosts
D. 62 usable hosts [CORRECT]
Correct Answer: D
Rationale: A /26 prefix leaves 6 host bits, giving 2 raised to the 6th power = 64 total addresses, minus the
network address and broadcast address, leaving 62 usable hosts. Option A (64) fails to subtract the two
reserved addresses, option B (30) corresponds to a /27, and option C (126) corresponds to a /25. (N10-009
Objective 1.3 - IPv4 subnetting and CIDR)
Q5. A host configured with the address 192.168.1.100/28 cannot communicate with a server at
192.168.1.65. Which subnet does the host actually belong to?
A. 192.168.1.64/28
B. 192.168.1.96/28 [CORRECT]
C. 192.168.1.80/28
D. 192.168.1.112/28
Correct Answer: B
Rationale: A /28 mask (255.255.255.240) creates subnets in block sizes of 16: 0, 16, 32, 48, 64, 80, 96,
112. The address 192.168.1.100 falls in the range 96 through 111, so its network is 192.168.1.96/28, while
192.168.1.65 resides in 192.168.1.64/28; the host and server are on different subnets. (N10-009 Objective
1.3 - Subnetting calculations)
Q6. Which of the following IPv4 addresses is a private address assigned from the RFC 1918 ranges?
A. 172.32.10.1
B. 172.16.12.5 [CORRECT]
C. 192.169.1.10
D. 169.254.9.1
Correct Answer: B
Rationale: The RFC 1918 private ranges are 10.0.0.0/8, 172.16.0.0/12 (172.16.0.0 through
172.31.255.255), and 192.168.0.0/16. The address 172.16.12.5 falls inside the 172.16/12 block; 172.32.x.x
(A) and 192.169.x.x (C) fall just outside the private blocks, and 169.254.x.x (D) is the APIPA link-local
range rather than an RFC 1918 range. (N10-009 Objective 1.3 - Public vs. private IP addressing)
Real Exam Questions and Verified Answers | Graded A+ 3
EXAMINATION
NETWORK+
N10-009 EXAM
Real exam questions and verified answers, fully
aligned with the official CompTIA Network+ N10-009
objectives. 130 multiple-choice and performance-
based questions covering networking fundamentals,
implementations, operations, security, and
troubleshooting.
2026/2027 Edition | 100% Correct | Graded A+
Multiple-Choice & Performance-Based | Verified Answers
130 QUESTI ONS | 7 EXAM D OMAI NS | C OMPL ETE
C E RTI F I C ATI O N E X A M I N ATI O N
,COMPTIA NETWORK+ (N10-009) EXAM | 2026/2027 EDITION
Table of Contents
Section 1: Networking Fundamentals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Section 2: Network Implementations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Section 3: Network Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Section 4: Network Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Section 5: Network Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Section 6: Performance-Based Questions (PBQs) . . . . . . . . . . . . . . . . . . . . . . . . 33
Section 7: Mixed Comprehensive Scenarios & Case Studies . . . . . . . . . . . . . . . . . . . 40
Real Exam Questions and Verified Answers | Graded A+ 1
,COMPTIA NETWORK+ (N10-009) EXAM | 2026/2027 EDITION
Section 1: Networking Fundamentals
Q1. A network technician observes that a core router forwards packets between different IP subnets
based on logical addresses. At which OSI model layer does the router primarily operate?
A. Data Link layer, using MAC address tables
B. Transport layer, using TCP sequence numbers
C. Network layer, using logical IP addressing and routing tables [CORRECT]
D. Session layer, using dialog control tokens
Correct Answer: C
Rationale: The Network layer (Layer 3) is responsible for logical addressing (IP) and route selection
between networks, which is exactly the function a router performs. The Data Link layer (A) handles MAC
addressing and frames within a local segment, the Transport layer (B) manages end-to-end TCP/UDP
delivery, and the Session layer (D) manages dialog establishment between applications. (N10-009 Objective
1.1 - OSI model layers and functions)
Q2. A junior administrator is mapping the four-layer TCP/IP model to the seven-layer OSI model.
Which pair of OSI layers corresponds to the TCP/IP Network Access (Link) layer?
A. Physical and Data Link [CORRECT]
B. Application and Presentation
C. Session and Transport
D. Network and Transport
Correct Answer: A
Rationale: The TCP/IP Network Access (Link) layer combines the OSI Physical layer (cabling, signaling)
and the Data Link layer (MAC, frames). The TCP/IP Application layer (B) maps to OSI Layers 5 through 7,
and the Internet layer maps to OSI Layer 3 only. (N10-009 Objective 1.1 - OSI and TCP/IP model
comparison)
Q3. Users report that outbound email messages are stuck in the mail server queue. Firewall logs show
that outbound connections to remote mail exchangers are being blocked. Which protocol and port
combination is most likely being blocked?
A. SMTP on TCP 25 [CORRECT]
B. POP3 on TCP 110
C. IMAP on TCP 143
D. HTTPS on TCP 443
Correct Answer: A
Rationale: Simple Mail Transfer Protocol uses TCP port 25 for server-to-server mail relay, so blocking
outbound TCP 25 stops messages from leaving the queue. POP3 (B) and IMAP (C) are client retrieval
protocols, and HTTPS (D) is web traffic, none of which relay mail between servers. (N10-009 Objective 1.4
- Well-known ports and protocols)
Real Exam Questions and Verified Answers | Graded A+ 2
, COMPTIA NETWORK+ (N10-009) EXAM | 2026/2027 EDITION
Q4. A network engineer is calculating address space for a department and must use the 192.168.10.0/26
subnet. How many usable host addresses are available in this subnet?
A. 64 usable hosts
B. 30 usable hosts
C. 126 usable hosts
D. 62 usable hosts [CORRECT]
Correct Answer: D
Rationale: A /26 prefix leaves 6 host bits, giving 2 raised to the 6th power = 64 total addresses, minus the
network address and broadcast address, leaving 62 usable hosts. Option A (64) fails to subtract the two
reserved addresses, option B (30) corresponds to a /27, and option C (126) corresponds to a /25. (N10-009
Objective 1.3 - IPv4 subnetting and CIDR)
Q5. A host configured with the address 192.168.1.100/28 cannot communicate with a server at
192.168.1.65. Which subnet does the host actually belong to?
A. 192.168.1.64/28
B. 192.168.1.96/28 [CORRECT]
C. 192.168.1.80/28
D. 192.168.1.112/28
Correct Answer: B
Rationale: A /28 mask (255.255.255.240) creates subnets in block sizes of 16: 0, 16, 32, 48, 64, 80, 96,
112. The address 192.168.1.100 falls in the range 96 through 111, so its network is 192.168.1.96/28, while
192.168.1.65 resides in 192.168.1.64/28; the host and server are on different subnets. (N10-009 Objective
1.3 - Subnetting calculations)
Q6. Which of the following IPv4 addresses is a private address assigned from the RFC 1918 ranges?
A. 172.32.10.1
B. 172.16.12.5 [CORRECT]
C. 192.169.1.10
D. 169.254.9.1
Correct Answer: B
Rationale: The RFC 1918 private ranges are 10.0.0.0/8, 172.16.0.0/12 (172.16.0.0 through
172.31.255.255), and 192.168.0.0/16. The address 172.16.12.5 falls inside the 172.16/12 block; 172.32.x.x
(A) and 192.169.x.x (C) fall just outside the private blocks, and 169.254.x.x (D) is the APIPA link-local
range rather than an RFC 1918 range. (N10-009 Objective 1.3 - Public vs. private IP addressing)
Real Exam Questions and Verified Answers | Graded A+ 3
