COMPTIA NETWORK+ N10-009
CERTIFICATION EXAM WITH QUESTIONS
AND VERIFIED ANSWERS, PLUS DETAILED
RATIONALES/EXPERT VERIFIED FOR
GUARANTEED PASS 2026/LATEST
UPDATE/INSTANT DOWNLOAD PDF
1. A network administrator is troubleshooting intermittent
connectivity between two switches. The switches are connected
using two Ethernet links, and both links are configured as active
forwarding paths. Users report periods of connectivity loss and
broadcast storms. Which technology should the administrator
configure to prevent this condition?
A. Link Aggregation Control Protocol (LACP)
B. Spanning Tree Protocol (STP)
C. Dynamic Host Configuration Protocol (DHCP)
D. Border Gateway Protocol (BGP)
Answer: B. Spanning Tree Protocol (STP)
Rationale: STP prevents Layer 2 switching loops by placing redundant
paths into a blocking state while maintaining them as backup paths.
Without loop prevention, redundant switch connections can create
broadcast storms, duplicate frames, and MAC-address-table instability.
LACP can combine links, but simply having multiple independent
links does not prevent loops.
2. A company wants employees to connect laptops to the corporate
wireless network using individual credentials rather than a shared
Wi-Fi password. The organization also wants authentication to be
1
, integrated with an existing centralized authentication server.
Which solution is most appropriate?
A. WPA2-Personal
B. WPA3-Personal
C. WPA2/WPA3-Enterprise with 802.1X
D. Open authentication
Answer: C. WPA2/WPA3-Enterprise with 802.1X
Rationale: Enterprise wireless authentication uses 802.1X and
typically an authentication server such as RADIUS. This allows
individual users or devices to authenticate rather than sharing a single
pre-shared key. Personal modes use a shared PSK and are less
appropriate for centralized per-user authentication.
3. A technician needs to determine why a workstation can
communicate with devices on its local subnet but cannot reach
remote networks. The workstation has an IP address of
192.168.50.25/24, but the default gateway field is blank. Which
configuration issue is most likely responsible?
A. Incorrect DNS server
B. Missing default gateway
C. Incorrect MAC address
D. Incorrect SSID
Answer: B. Missing default gateway
Rationale: The default gateway provides the Layer 3 path from the
local subnet to other networks. A host can communicate with devices
on its own /24 subnet without a gateway, but traffic destined for
another subnet requires a properly configured default gateway. DNS
affects name resolution rather than basic routing to known IP
addresses.
2
, 4. An IPv4 host has automatically configured itself with an address in
the 169.254.0.0/16 range. The host cannot access network
resources. What is the most likely explanation?
A. The DNS server is unavailable
B. The DHCP server could not provide a valid lease
C. The default gateway is using IPv6
D. The switch is blocking HTTPS
Answer: B. The DHCP server could not provide a valid lease
Rationale: A 169.254.0.0/16 address is an IPv4 link-local/APIPA
address. Windows hosts commonly assign this type of address when
DHCP fails or cannot be reached. Such an address permits limited
local-link communication but normally does not provide normal
enterprise network connectivity.
5. A network engineer wants to divide a 192.168.10.0/24 network
into eight equal-sized IPv4 subnets. Which subnet mask should be
used?
A. /25
B. /26
C. /27
D. /28
Answer: C. /27
Rationale: A /24 contains 256 addresses. Borrowing 3 host bits creates
2³ = 8 subnets. The resulting prefix is /27, providing 32 addresses per
subnet, including the network and broadcast addresses, with 30 usable
host addresses under traditional IPv4 subnetting.
3
, 6. Which protocol is primarily responsible for dynamically resolving
an IPv4 address to a corresponding MAC address on a local
Ethernet network?
A. DNS
B. ARP
C. DHCP
D. ICMP
Answer: B. ARP
Rationale: Address Resolution Protocol (ARP) maps an IPv4 address
to a MAC address on a local Layer 2 network. DNS maps names to IP
addresses, DHCP provides configuration information, and ICMP is
primarily used for control and diagnostic messaging.
7. A technician executes ping 127.0.0.1 on a workstation. What is the
primary purpose of this test?
A. Verify Internet connectivity
B. Test the local TCP/IP stack
C. Test DNS resolution
D. Test the default gateway
Answer: B. Test the local TCP/IP stack
Rationale: 127.0.0.1 is the IPv4 loopback address. Pinging it tests
whether the local host's TCP/IP networking stack is functioning. It
does not test the physical network interface, switch, gateway, DNS
server, or Internet connection.
8. A network uses OSPF to exchange routing information between
routers. Which characteristic best describes OSPF?
4
CERTIFICATION EXAM WITH QUESTIONS
AND VERIFIED ANSWERS, PLUS DETAILED
RATIONALES/EXPERT VERIFIED FOR
GUARANTEED PASS 2026/LATEST
UPDATE/INSTANT DOWNLOAD PDF
1. A network administrator is troubleshooting intermittent
connectivity between two switches. The switches are connected
using two Ethernet links, and both links are configured as active
forwarding paths. Users report periods of connectivity loss and
broadcast storms. Which technology should the administrator
configure to prevent this condition?
A. Link Aggregation Control Protocol (LACP)
B. Spanning Tree Protocol (STP)
C. Dynamic Host Configuration Protocol (DHCP)
D. Border Gateway Protocol (BGP)
Answer: B. Spanning Tree Protocol (STP)
Rationale: STP prevents Layer 2 switching loops by placing redundant
paths into a blocking state while maintaining them as backup paths.
Without loop prevention, redundant switch connections can create
broadcast storms, duplicate frames, and MAC-address-table instability.
LACP can combine links, but simply having multiple independent
links does not prevent loops.
2. A company wants employees to connect laptops to the corporate
wireless network using individual credentials rather than a shared
Wi-Fi password. The organization also wants authentication to be
1
, integrated with an existing centralized authentication server.
Which solution is most appropriate?
A. WPA2-Personal
B. WPA3-Personal
C. WPA2/WPA3-Enterprise with 802.1X
D. Open authentication
Answer: C. WPA2/WPA3-Enterprise with 802.1X
Rationale: Enterprise wireless authentication uses 802.1X and
typically an authentication server such as RADIUS. This allows
individual users or devices to authenticate rather than sharing a single
pre-shared key. Personal modes use a shared PSK and are less
appropriate for centralized per-user authentication.
3. A technician needs to determine why a workstation can
communicate with devices on its local subnet but cannot reach
remote networks. The workstation has an IP address of
192.168.50.25/24, but the default gateway field is blank. Which
configuration issue is most likely responsible?
A. Incorrect DNS server
B. Missing default gateway
C. Incorrect MAC address
D. Incorrect SSID
Answer: B. Missing default gateway
Rationale: The default gateway provides the Layer 3 path from the
local subnet to other networks. A host can communicate with devices
on its own /24 subnet without a gateway, but traffic destined for
another subnet requires a properly configured default gateway. DNS
affects name resolution rather than basic routing to known IP
addresses.
2
, 4. An IPv4 host has automatically configured itself with an address in
the 169.254.0.0/16 range. The host cannot access network
resources. What is the most likely explanation?
A. The DNS server is unavailable
B. The DHCP server could not provide a valid lease
C. The default gateway is using IPv6
D. The switch is blocking HTTPS
Answer: B. The DHCP server could not provide a valid lease
Rationale: A 169.254.0.0/16 address is an IPv4 link-local/APIPA
address. Windows hosts commonly assign this type of address when
DHCP fails or cannot be reached. Such an address permits limited
local-link communication but normally does not provide normal
enterprise network connectivity.
5. A network engineer wants to divide a 192.168.10.0/24 network
into eight equal-sized IPv4 subnets. Which subnet mask should be
used?
A. /25
B. /26
C. /27
D. /28
Answer: C. /27
Rationale: A /24 contains 256 addresses. Borrowing 3 host bits creates
2³ = 8 subnets. The resulting prefix is /27, providing 32 addresses per
subnet, including the network and broadcast addresses, with 30 usable
host addresses under traditional IPv4 subnetting.
3
, 6. Which protocol is primarily responsible for dynamically resolving
an IPv4 address to a corresponding MAC address on a local
Ethernet network?
A. DNS
B. ARP
C. DHCP
D. ICMP
Answer: B. ARP
Rationale: Address Resolution Protocol (ARP) maps an IPv4 address
to a MAC address on a local Layer 2 network. DNS maps names to IP
addresses, DHCP provides configuration information, and ICMP is
primarily used for control and diagnostic messaging.
7. A technician executes ping 127.0.0.1 on a workstation. What is the
primary purpose of this test?
A. Verify Internet connectivity
B. Test the local TCP/IP stack
C. Test DNS resolution
D. Test the default gateway
Answer: B. Test the local TCP/IP stack
Rationale: 127.0.0.1 is the IPv4 loopback address. Pinging it tests
whether the local host's TCP/IP networking stack is functioning. It
does not test the physical network interface, switch, gateway, DNS
server, or Internet connection.
8. A network uses OSPF to exchange routing information between
routers. Which characteristic best describes OSPF?
4
