CompTIA Network+ N10-009 IPv4 Addressing CIDR VLSM And Subnetting Practice Test

 

Objective 1.7 • 20 original questions

This CompTIA Network+ N10-009 practice test focuses on IPv4 addressing and subnetting. All questions are original ExamSnap scenarios aligned to the current N10-009 blueprint; they are not copied from CompTIA exam content. Use the complete N10-009 collection for broader practice across all five domains. For broader exam preparation, review the CompTIA Network+ N10-009 Exam Dumps page.

Instructions: Select the best answer for each question. Review the explanation after answering; each distractor includes a reason it is not the best choice for that scenario.

Question 1

A network technician at Contoso Health needs the smallest IPv4 subnet that supports at least 200 usable host addresses. Which prefix length should be selected?

1. /26
2. /25
3. /23
4. /22
5. /24

Correct answer: E

Why: A /24 provides 254 traditional usable host addresses. This is the smallest option that meets the requirement.

Option review:

A: A /26 provides 62 traditional usable host addresses. It does not provide the smallest valid capacity for the requirement.

B: A /25 provides 126 traditional usable host addresses. It does not provide the smallest valid capacity for the requirement.

C: A /23 provides 510 traditional usable host addresses. It does not provide the smallest valid capacity for the requirement.

D: A /22 provides 1022 traditional usable host addresses. It does not provide the smallest valid capacity for the requirement.

E: A /24 provides 254 traditional usable host addresses. This is the smallest option that meets the requirement.

Learning point: A /24 is the smallest conventional IPv4 subnet that provides at least 200 usable host addresses.

Question 2

Host 172.20.201.132 is configured with prefix /26. Which network address contains this host?

172. 172.20.201.64
173. 172.20.201.192
174. 172.20.201.0
175. 172.20.202.0
176. 172.20.201.128

Correct answer: E

Why: Applying the /26 mask to 172.20.201.132 yields network 172.20.201.128.

Option review:

A: 172.20.201.64 is not the network boundary for 172.20.201.132/26.

B: 172.20.201.192 is not the network boundary for 172.20.201.132/26.

C: 172.20.201.0 is not the network boundary for 172.20.201.132/26.

D: 172.20.202.0 is not the network boundary for 172.20.201.132/26.

E: Applying the /26 mask to 172.20.201.132 yields network 172.20.201.128.

Learning point: 172.20.201.132/26 belongs to network 172.20.201.128/26.

Question 3

At Northwind Logistics, which IPv4 address is the broadcast address for subnet 192.168.99.16/28?

192. 192.168.99.30
193. 192.168.99.16
194. 192.168.99.31
195. 192.168.99.32
196. 192.168.99.17

Correct answer: C

Why: 192.168.99.31 is the last address in the subnet and therefore the broadcast address.

Option review:

A: 192.168.99.30 is not the broadcast address for this subnet.

B: 192.168.99.16 is not the broadcast address for this subnet.

C: 192.168.99.31 is the last address in the subnet and therefore the broadcast address.

D: 192.168.99.32 is not the broadcast address for this subnet.

E: 192.168.99.17 is not the broadcast address for this subnet.

Learning point: The broadcast address of 192.168.99.16/28 is 192.168.99.31.

Question 4

How should IPv4 address 127.0.0.1 be classified for Network+ troubleshooting purposes?

1. Class D / multicast range
2. APIPA/link-local
3. Public IPv4 address
4. Loopback/localhost
5. RFC1918 private address

Correct answer: D

Why: 127.0.0.1 matches the Loopback/localhost category.

Option review:

A: 127.0.0.1 does not fall into the Class D / multicast range category.

B: 127.0.0.1 does not fall into the APIPA/link-local category.

C: 127.0.0.1 does not fall into the Public IPv4 address category.

D: 127.0.0.1 matches the Loopback/localhost category.

E: 127.0.0.1 does not fall into the RFC1918 private address category.

Learning point: 127.0.0.1 is classified as Loopback/localhost.

Question 5

Adventure Works must divide a /24 network among departments needing different host capacities while minimizing wasted addresses. Which addressing technique best fits?

1. Loopback addressing
2. VLSM
3. Use one /24 for every department
4. APIPA
5. Classful addressing only

Correct answer: B

Why: Variable Length Subnet Masking allows different prefix sizes inside the address block to match different host needs.

Option review:

A: Loopback addressing does not efficiently create differently sized subnets from the available block.

B: Variable Length Subnet Masking allows different prefix sizes inside the address block to match different host needs.

C: Use one /24 for every department does not efficiently create differently sized subnets from the available block.

D: APIPA does not efficiently create differently sized subnets from the available block.

E: Classful addressing only does not efficiently create differently sized subnets from the available block.

Learning point: VLSM uses different prefix lengths to match subnet sizes to actual host requirements.

Question 6

A field technician at Tailspin Toys needs the smallest IPv4 subnet that supports at least 30 usable host addresses. Which prefix length should be selected?

1. /27
2. /25
3. /29
4. /26
5. /28

Correct answer: A

Why: A /27 provides 30 traditional usable host addresses. This is the smallest option that meets the requirement.

Option review:

A: A /27 provides 30 traditional usable host addresses. This is the smallest option that meets the requirement.

B: A /25 provides 126 traditional usable host addresses. It does not provide the smallest valid capacity for the requirement.

C: A /29 provides 6 traditional usable host addresses. It does not provide the smallest valid capacity for the requirement.

D: A /26 provides 62 traditional usable host addresses. It does not provide the smallest valid capacity for the requirement.

E: A /28 provides 14 traditional usable host addresses. It does not provide the smallest valid capacity for the requirement.

Learning point: A /27 is the smallest conventional IPv4 subnet that provides at least 30 usable host addresses.

Question 7

Host 10.44.243.20 is configured with prefix /28. Which network address contains this host?

10. 10.44.243.0
11. 10.44.243.32
12. 10.44.243.48
13. 10.44.243.16
14. 10.44.242.240

Correct answer: D

Why: Applying the /28 mask to 10.44.243.20 yields network 10.44.243.16.

Option review:

A: 10.44.243.0 is not the network boundary for 10.44.243.20/28.

B: 10.44.243.32 is not the network boundary for 10.44.243.20/28.

C: 10.44.243.48 is not the network boundary for 10.44.243.20/28.

D: Applying the /28 mask to 10.44.243.20 yields network 10.44.243.16.

E: 10.44.242.240 is not the network boundary for 10.44.243.20/28.

Learning point: 10.44.243.20/28 belongs to network 10.44.243.16/28.

Question 8

At Proseware Media, which IPv4 address is the broadcast address for subnet 172.16.8.128/25?

172. 172.16.8.129
173. 172.16.8.128
174. 172.16.8.254
175. 172.16.9.0
176. 172.16.8.255

Correct answer: E

Why: 172.16.8.255 is the last address in the subnet and therefore the broadcast address.

Option review:

A: 172.16.8.129 is not the broadcast address for this subnet.

B: 172.16.8.128 is not the broadcast address for this subnet.

C: 172.16.8.254 is not the broadcast address for this subnet.

D: 172.16.9.0 is not the broadcast address for this subnet.

E: 172.16.8.255 is the last address in the subnet and therefore the broadcast address.

Learning point: The broadcast address of 172.16.8.128/25 is 172.16.8.255.

Question 9

How should IPv4 address 169.254.22.4 be classified for Network+ troubleshooting purposes?

1. APIPA/link-local
2. Class D / multicast range
3. RFC1918 private address
4. Public IPv4 address
5. Loopback/localhost

Correct answer: A

Why: 169.254.22.4 matches the APIPA/link-local category.

Option review:

A: 169.254.22.4 matches the APIPA/link-local category.

B: 169.254.22.4 does not fall into the Class D / multicast range category.

C: 169.254.22.4 does not fall into the RFC1918 private address category.

D: 169.254.22.4 does not fall into the Public IPv4 address category.

E: 169.254.22.4 does not fall into the Loopback/localhost category.

Learning point: 169.254.22.4 is classified as APIPA/link-local.

Question 10

Blue Yonder Airlines must divide a /24 network among departments needing different host capacities while minimizing wasted addresses. Which addressing technique best fits?

1. Loopback addressing
2. APIPA
3. Use one /24 for every department
4. VLSM
5. Classful addressing only

Correct answer: D

Why: Variable Length Subnet Masking allows different prefix sizes inside the address block to match different host needs.

Option review:

A: Loopback addressing does not efficiently create differently sized subnets from the available block.

B: APIPA does not efficiently create differently sized subnets from the available block.

C: Use one /24 for every department does not efficiently create differently sized subnets from the available block.

D: Variable Length Subnet Masking allows different prefix sizes inside the address block to match different host needs.

E: Classful addressing only does not efficiently create differently sized subnets from the available block.

Learning point: VLSM uses different prefix lengths to match subnet sizes to actual host requirements.

Question 11

A network support specialist at Fourth Coffee needs the smallest IPv4 subnet that supports at least 500 usable host addresses. Which prefix length should be selected?

1. /25
2. /22
3. /21
4. /24
5. /23

Correct answer: E

Why: A /23 provides 510 traditional usable host addresses. This is the smallest option that meets the requirement.

Option review:

A: A /25 provides 126 traditional usable host addresses. It does not provide the smallest valid capacity for the requirement.

B: A /22 provides 1022 traditional usable host addresses. It does not provide the smallest valid capacity for the requirement.

C: A /21 provides 2046 traditional usable host addresses. It does not provide the smallest valid capacity for the requirement.

D: A /24 provides 254 traditional usable host addresses. It does not provide the smallest valid capacity for the requirement.

E: A /23 provides 510 traditional usable host addresses. This is the smallest option that meets the requirement.

Learning point: A /23 is the smallest conventional IPv4 subnet that provides at least 500 usable host addresses.

Question 12

Host 10.44.208.4 is configured with prefix /24. Which network address contains this host?

10. 10.44.209.0
11. 10.44.208.0
12. 10.44.210.0
13. 10.44.207.0
14. 10.44.206.0

Correct answer: B

Why: Applying the /24 mask to 10.44.208.4 yields network 10.44.208.0.

Option review:

A: 10.44.209.0 is not the network boundary for 10.44.208.4/24.

B: Applying the /24 mask to 10.44.208.4 yields network 10.44.208.0.

C: 10.44.210.0 is not the network boundary for 10.44.208.4/24.

D: 10.44.207.0 is not the network boundary for 10.44.208.4/24.

E: 10.44.206.0 is not the network boundary for 10.44.208.4/24.

Learning point: 10.44.208.4/24 belongs to network 10.44.208.0/24.

Question 13

At Contoso Health, which IPv4 address is the broadcast address for subnet 192.168.99.16/28?

192. 192.168.99.31
193. 192.168.99.30
194. 192.168.99.17
195. 192.168.99.16
196. 192.168.99.32

Correct answer: A

Why: 192.168.99.31 is the last address in the subnet and therefore the broadcast address.

Option review:

A: 192.168.99.31 is the last address in the subnet and therefore the broadcast address.

B: 192.168.99.30 is not the broadcast address for this subnet.

C: 192.168.99.17 is not the broadcast address for this subnet.

D: 192.168.99.16 is not the broadcast address for this subnet.

E: 192.168.99.32 is not the broadcast address for this subnet.

Learning point: The broadcast address of 192.168.99.16/28 is 192.168.99.31.

Question 14

How should IPv4 address 10.10.5.20 be classified for Network+ troubleshooting purposes?

1. RFC1918 private address
2. Public IPv4 address
3. Loopback/localhost
4. Class D / multicast range
5. APIPA/link-local

Correct answer: A

Why: 10.10.5.20 matches the RFC1918 private address category.

Option review:

A: 10.10.5.20 matches the RFC1918 private address category.

B: 10.10.5.20 does not fall into the Public IPv4 address category.

C: 10.10.5.20 does not fall into the Loopback/localhost category.

D: 10.10.5.20 does not fall into the Class D / multicast range category.

E: 10.10.5.20 does not fall into the APIPA/link-local category.

Learning point: 10.10.5.20 is classified as RFC1918 private address.

Question 15

Northwind Logistics must divide a /24 network among departments needing different host capacities while minimizing wasted addresses. Which addressing technique best fits?

1. Classful addressing only
2. VLSM
3. Loopback addressing
4. APIPA
5. Use one /24 for every department

Correct answer: B

Why: Variable Length Subnet Masking allows different prefix sizes inside the address block to match different host needs.

Option review:

A: Classful addressing only does not efficiently create differently sized subnets from the available block.

B: Variable Length Subnet Masking allows different prefix sizes inside the address block to match different host needs.

C: Loopback addressing does not efficiently create differently sized subnets from the available block.

D: APIPA does not efficiently create differently sized subnets from the available block.

E: Use one /24 for every department does not efficiently create differently sized subnets from the available block.

Learning point: VLSM uses different prefix lengths to match subnet sizes to actual host requirements.

Question 16

A systems administrator at Litware Manufacturing needs the smallest IPv4 subnet that supports at least 50 usable host addresses. Which prefix length should be selected?

1. /24
2. /27
3. /25
4. /28
5. /26

Correct answer: E

Why: A /26 provides 62 traditional usable host addresses. This is the smallest option that meets the requirement.

Option review:

A: A /24 provides 254 traditional usable host addresses. It does not provide the smallest valid capacity for the requirement.

B: A /27 provides 30 traditional usable host addresses. It does not provide the smallest valid capacity for the requirement.

C: A /25 provides 126 traditional usable host addresses. It does not provide the smallest valid capacity for the requirement.

D: A /28 provides 14 traditional usable host addresses. It does not provide the smallest valid capacity for the requirement.

E: A /26 provides 62 traditional usable host addresses. This is the smallest option that meets the requirement.

Learning point: A /26 is the smallest conventional IPv4 subnet that provides at least 50 usable host addresses.

Question 17

Host 10.20.245.4 is configured with prefix /25. Which network address contains this host?

10. 10.20.246.0
11. 10.20.244.0
12. 10.20.245.128
13. 10.20.245.0
14. 10.20.244.128

Correct answer: D

Why: Applying the /25 mask to 10.20.245.4 yields network 10.20.245.0.

Option review:

A: 10.20.246.0 is not the network boundary for 10.20.245.4/25.

B: 10.20.244.0 is not the network boundary for 10.20.245.4/25.

C: 10.20.245.128 is not the network boundary for 10.20.245.4/25.

D: Applying the /25 mask to 10.20.245.4 yields network 10.20.245.0.

E: 10.20.244.128 is not the network boundary for 10.20.245.4/25.

Learning point: 10.20.245.4/25 belongs to network 10.20.245.0/25.

Question 18

At Tailspin Toys, which IPv4 address is the broadcast address for subnet 192.168.10.64/26?

192. 192.168.10.65
193. 192.168.10.127
194. 192.168.10.126
195. 192.168.10.128
196. 192.168.10.64

Correct answer: B

Why: 192.168.10.127 is the last address in the subnet and therefore the broadcast address.

Option review:

A: 192.168.10.65 is not the broadcast address for this subnet.

B: 192.168.10.127 is the last address in the subnet and therefore the broadcast address.

C: 192.168.10.126 is not the broadcast address for this subnet.

D: 192.168.10.128 is not the broadcast address for this subnet.

E: 192.168.10.64 is not the broadcast address for this subnet.

Learning point: The broadcast address of 192.168.10.64/26 is 192.168.10.127.

Question 19

How should IPv4 address 172.20.3.9 be classified for Network+ troubleshooting purposes?

1. APIPA/link-local
2. RFC1918 private address
3. Loopback/localhost
4. Public IPv4 address
5. Class D / multicast range

Correct answer: B

Why: 172.20.3.9 matches the RFC1918 private address category.

Option review:

A: 172.20.3.9 does not fall into the APIPA/link-local category.

B: 172.20.3.9 matches the RFC1918 private address category.

C: 172.20.3.9 does not fall into the Loopback/localhost category.

D: 172.20.3.9 does not fall into the Public IPv4 address category.

E: 172.20.3.9 does not fall into the Class D / multicast range category.

Learning point: 172.20.3.9 is classified as RFC1918 private address.

Question 20

Proseware Media must divide a /24 network among departments needing different host capacities while minimizing wasted addresses. Which addressing technique best fits?

1. APIPA
2. Loopback addressing
3. Classful addressing only
4. Use one /24 for every department
5. VLSM

Correct answer: E

Why: Variable Length Subnet Masking allows different prefix sizes inside the address block to match different host needs.

Option review:

A: APIPA does not efficiently create differently sized subnets from the available block.

B: Loopback addressing does not efficiently create differently sized subnets from the available block.

C: Classful addressing only does not efficiently create differently sized subnets from the available block.

D: Use one /24 for every department does not efficiently create differently sized subnets from the available block.

E: Variable Length Subnet Masking allows different prefix sizes inside the address block to match different host needs.

Learning point: VLSM uses different prefix lengths to match subnet sizes to actual host requirements.