Subnetting Test with 20 Questions | IP Subnetting Quiz 3

Test your networking knowledge with Subnetting Quiz 3! This IP Subnetting Quiz includes 20 subnetting questions covering CIDR, VLSM, subnet masks, usable host addresses, binary conversions, and route summarization. Take this Subnetting Test, practice different IPv4 subnetting calculations and improve your skills for the CCNA certification exam.

Subnetting Questions – Quiz 3

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Question 1

What is the network address of the IPv4 host 172.16.1.2/24?

A	172.16.0.0/24
B	172.16.1.255/24
C	172.16.1.254/24
D	172.16.1.0/24
E	172.16.0.1/24

Question 1 Explanation:

A /24 subnet uses the mask 255.255.255.0. The first three octets identify the network, so 172.16.1.2 belongs to 172.16.1.0/24.

Question 2

A network engineer needs to create a subnet for 25 hosts using VLSM. Which subnet mask provides the smallest suitable subnet?

A	255.255.255.128
B	255.255.255.0
C	255.255.255.224
D	255.255.255.240
E	255.255.255.192

Question 2 Explanation:

A /27 subnet provides 32 total IP addresses and 30 usable host addresses. A /28 subnet supports only 14 usable hosts. Therefore, /27 is the smallest suitable subnet for 25 hosts.

Question 3

A network engineer needs a subnet that supports at least 158 usable IPv4 host addresses. Which subnet mask provides the smallest suitable subnet?

A	255.255.0.0
B	255.255.255.240
C	255.255.255.0
D	255.255.254.0
E	255.255.128.0

Question 3 Explanation:

A /24 subnet provides 256 total addresses and 254 usable host addresses. A /25 supports only 126 usable hosts, so /24 is the smallest suitable subnet.

Question 4

Which addressing method allows IPv4 networks to use variable-length prefixes instead of being restricted to traditional Class A, B, and C boundaries?

A	NAT
B	DHCP
C	CIDR
D	ARP
E	VLSM

Question 4 Explanation:

Classless Inter-Domain Routing (CIDR) uses variable-length network prefixes, allowing more flexible IP address allocation and route aggregation than traditional classful addressing.

Question 5

What is the 8-bit binary equivalent of the decimal number 56?

A	00111000
B	01011011
C	00111011
D	10111011
E	01111011

Question 6

What is the correct binary representation of the subnet mask 255.255.255.240?

A	11111111.11111111.11111111.00000000
B	11111111.11111111.11111111.11000000
C	11111111.11111111.11111111.10000000
D	11111111.11111111.11111111.11111111
E	11111111.11111111.11111111.11110000

Question 7

Which of the following IPv4 addresses belongs to Class C in classful addressing?

A	172.16.192.168
B	10.8.43.1
C	10.8.192.168
D	192.168.200.9
E	172.16.5.6

Question 8

What is the first usable host address in the IPv4 network 122.11.100.0/30?

A	122.11.153.255
B	122.11.100.1
C	122.11.53.1
D	122.11.1.1
E	122.11.100.0

Question 8 Explanation:

A traditional /30 subnet contains 4 addresses: one network address, two usable host addresses, and one broadcast address. The first usable host address is 122.11.100.1.

Question 9

Which IPv4 address class does 10.10.1.16 belong to in classful addressing?

A	E
B	D
C	C
D	B
E	A

Question 10

Which summary route covers both 192.168.8.0/24 and 192.168.9.0/24 without including any additional networks?

A	192.168.8.0/24
B	192.168.0.0/20
C	192.168.9.0/23
D	192.168.8.0/23
E	192.168.8.0/22

Question 10 Explanation:

The networks 192.168.8.0/24 and 192.168.9.0/24 are contiguous and share the first 23 bits. They can be summarized as 192.168.8.0/23, covering the address range 192.168.8.0–192.168.9.255 without including additional networks.

Question 11

Which IPv4 subnet contains the host address 70.14.10.25/18?

A	70.14.32.0/18
B	70.14.0.1/18
C	70.14.128.0/18
D	70.14.1.0/18
E	70.14.0.0/18

Question 11 Explanation:

A /18 subnet uses the mask 255.255.192.0, creating blocks of 64 in the third octet. The address 70.14.10.25 belongs to 70.14.0.0/18.

Question 12

A company divides the network 172.16.0.0/24 into equal-sized /30 subnets. How many subnets are created, and how many usable host addresses are available in each subnet?

A	64 subnets, 2 usable hosts
B	32 subnets, 6 usable hosts
C	64 subnets, 4 usable hosts
D	128 subnets, 2 usable hosts
E	32 subnets, 2 usable hosts

Question 12 Explanation:

Moving from /24 to /30 borrows 6 bits, creating 64 equal-sized subnets. Each traditional /30 subnet provides 2 usable host addresses.

Question 13

What is the broadcast address of the IPv4 network 192.168.100.0/29?

A	192.168.100.255
B	192.168.100.0
C	192.168.100.7
D	192.168.100.1
E	192.168.100.19

Question 13 Explanation:

A /29 subnet contains 8 addresses. The network address is 192.168.100.0 and the broadcast address is 192.168.100.7.

Question 14

Which usable host range contains the IPv4 address 195.105.16.5/29?

A	195.105.16.1 – 195.105.16.6
B	195.105.16.0 – 195.105.16.15
C	195.105.16.1 – 195.105.16.14
D	195.105.16.0 – 195.105.16.7
E	195.105.16.8 – 195.105.16.14

Question 14 Explanation:

The address belongs to 195.105.16.0/29. The network address is 195.105.16.0 and the broadcast address is 195.105.16.7, leaving the usable range 195.105.16.1–195.105.16.6.

Question 15

What is the dotted-decimal subnet mask for an IPv4 /30 prefix?

A	255.255.255.224
B	255.255.255.240
C	255.255.255.252
D	255.255.255.248
E	255.255.255.254

Question 16

What is the last usable host address in the IPv4 network 12.75.72.0/27?

A	12.75.72.1
B	12.75.72.0
C	12.75.72.255
D	12.75.72.30
E	12.75.72.254

Question 16 Explanation:

A /27 subnet contains 32 addresses. The network address is 12.75.72.0, the broadcast address is 12.75.72.31, and the last usable host address is 12.75.72.30.

Question 17

What is the decimal equivalent of the 8-bit binary number 01111010?

A	60
B	120
C	122
D	68
E	62

Question 18

A network engineer is given the IPv4 address 80.4.9.1/27. Which of the following addresses belongs to the same subnet and can be assigned to a host?

A	80.4.9.0
B	80.4.9.31
C	80.4.9.32
D	80.4.8.30
E	80.4.9.25

Question 18 Explanation:

The address 80.4.9.1/27 belongs to the network 80.4.9.0/27. Its usable host range is 80.4.9.1–80.4.9.30, making 80.4.9.25 a valid host address.

Question 19

Which of the following is the correct binary representation of the IPv4 address 72.190.1.120?

A	01001000.10100110.00000001.01111000
B	01001000.10100110.00000001.01111011
C	01001000.10100110.00110001.01111000
D	01001000.10100110.00000111.01111000
E	01001000.10111110.00000001.01111000

Question 20

A company has the network 200.180.35.0/24 and needs at least 6 equal-sized subnets. Each subnet must support at least 5 usable host addresses. Which subnet mask creates the smallest suitable subnets while meeting both requirements?

A	255.255.255.192
B	255.255.255.252
C	255.255.255.240
D	255.255.255.248
E	255.255.255.224

Question 20 Explanation:

A /29 subnet provides 8 total addresses and 6 usable host addresses. Dividing a /24 into /29 subnets creates 32 subnets, satisfying both requirements while minimizing unused addresses in each subnet.

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Gokhan Kosem is a Network Engineer, Instructor and the Founder of IPCisco.com with 15+ years of experience in Cisco, Nokia, Huawei, Juniper, Linux, Service Provider Networks, Routing and Switching technologies.

He has worked on the backbone networks of major service providers and network vendors including Nortel, Alcatel-Lucent (Nokia) and has extensive hands-on experience with Cisco, Huawei, Juniper and Nokia networking technologies.

He has trained thousands of networking students worldwide through IPCisco.com, Udemy, books, labs, quizzes, and educational content across multiple social media platforms.

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Subnetting Quiz 3

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