CompTIA Network+ 2026 Practice Questions and Answers
with Detailed Rationales – N10-009 Exam Prep
1. Which OSI model layer is responsible for logical addressing and routing packets
between networks?
A. Data Link
B. Network
C. Transport
D. Session
Answer: B. Network
Rationale: The Network layer (Layer 3) handles logical addressing, such as IPv4/IPv6
addresses, and routing packets between different networks.
2. Which protocol is primarily used to automatically assign IP addresses to hosts?
A. DNS
B. DHCP
C. ARP
D. SNMP
Answer: B. DHCP
Rationale: DHCP automatically provides clients with IP addresses and other network
configuration information such as the subnet mask, default gateway, and DNS servers.
,3. A technician needs to identify the MAC address associated with an IPv4 address on
the local network. Which protocol should be used?
A. DNS
B. ARP
C. DHCP
D. ICMP
Answer: B. ARP
Rationale: Address Resolution Protocol maps an IPv4 address to the corresponding
MAC address on a local network.
4. Which device primarily operates at OSI Layer 2 and forwards frames based on MAC
addresses?
A. Router
B. Switch
C. Firewall
D. Modem
Answer: B. Switch
Rationale: Ethernet switches primarily operate at Layer 2 and use MAC address tables
to forward frames to the appropriate port.
5. Which subnet mask corresponds to a /24 IPv4 network?
A. 255.255.0.0
,B. 255.255.255.0
C. 255.255.255.128
D. 255.255.255.252
Answer: B. 255.255.255.0
Rationale: A /24 prefix contains 24 network bits, producing the subnet mask
255.255.255.0.
6. Which IPv4 address is a private address?
A. 8.8.8.8
B. 172.20.10.5
C. 169.254.10.20
D. 203.0.113.10
Answer: B. 172.20.10.5
Rationale: The private IPv4 ranges include 10.0.0.0/8, 172.16.0.0/12, and
192.168.0.0/16. The address 172.20.10.5 falls within the second range.
7. Which technology allows multiple VLANs to traverse a single physical switch
connection?
A. Access port
B. Trunking
C. Port mirroring
D. NAT
, Answer: B. Trunking
Rationale: A trunk carries traffic for multiple VLANs across one physical link, commonly
using IEEE 802.1Q tagging.
8. What is the primary purpose of a VLAN?
A. Increase cable length
B. Create logical network segmentation
C. Replace IP addressing
D. Encrypt all network traffic
Answer: B. Create logical network segmentation
Rationale: VLANs logically divide a switched network into separate broadcast domains,
improving segmentation and network organization.
9. Which protocol is commonly used to securely access a network device’s command-
line interface remotely?
A. Telnet
B. FTP
C. SSH
D. TFTP
with Detailed Rationales – N10-009 Exam Prep
1. Which OSI model layer is responsible for logical addressing and routing packets
between networks?
A. Data Link
B. Network
C. Transport
D. Session
Answer: B. Network
Rationale: The Network layer (Layer 3) handles logical addressing, such as IPv4/IPv6
addresses, and routing packets between different networks.
2. Which protocol is primarily used to automatically assign IP addresses to hosts?
A. DNS
B. DHCP
C. ARP
D. SNMP
Answer: B. DHCP
Rationale: DHCP automatically provides clients with IP addresses and other network
configuration information such as the subnet mask, default gateway, and DNS servers.
,3. A technician needs to identify the MAC address associated with an IPv4 address on
the local network. Which protocol should be used?
A. DNS
B. ARP
C. DHCP
D. ICMP
Answer: B. ARP
Rationale: Address Resolution Protocol maps an IPv4 address to the corresponding
MAC address on a local network.
4. Which device primarily operates at OSI Layer 2 and forwards frames based on MAC
addresses?
A. Router
B. Switch
C. Firewall
D. Modem
Answer: B. Switch
Rationale: Ethernet switches primarily operate at Layer 2 and use MAC address tables
to forward frames to the appropriate port.
5. Which subnet mask corresponds to a /24 IPv4 network?
A. 255.255.0.0
,B. 255.255.255.0
C. 255.255.255.128
D. 255.255.255.252
Answer: B. 255.255.255.0
Rationale: A /24 prefix contains 24 network bits, producing the subnet mask
255.255.255.0.
6. Which IPv4 address is a private address?
A. 8.8.8.8
B. 172.20.10.5
C. 169.254.10.20
D. 203.0.113.10
Answer: B. 172.20.10.5
Rationale: The private IPv4 ranges include 10.0.0.0/8, 172.16.0.0/12, and
192.168.0.0/16. The address 172.20.10.5 falls within the second range.
7. Which technology allows multiple VLANs to traverse a single physical switch
connection?
A. Access port
B. Trunking
C. Port mirroring
D. NAT
, Answer: B. Trunking
Rationale: A trunk carries traffic for multiple VLANs across one physical link, commonly
using IEEE 802.1Q tagging.
8. What is the primary purpose of a VLAN?
A. Increase cable length
B. Create logical network segmentation
C. Replace IP addressing
D. Encrypt all network traffic
Answer: B. Create logical network segmentation
Rationale: VLANs logically divide a switched network into separate broadcast domains,
improving segmentation and network organization.
9. Which protocol is commonly used to securely access a network device’s command-
line interface remotely?
A. Telnet
B. FTP
C. SSH
D. TFTP
