Subnetting questions and answers are key to understanding network engineering. For network engineers, system administrators, and networking professionals, understanding subnetting is essential to optimizing IP address allocation, enhancing routing efficiency, and ensuring network security. It plays a crucial role in preparing for certification exams such as CCNA, CCNP, and CCIE.
Subnetting involves dividing large networks into smaller subnetworks, making management simpler and more efficient. This technique not only improves network performance but also enhances security and reduces network congestion by creating structured and easily manageable address spaces. To help professionals prepare for these exams and improve their skills, we’ve compiled the top 50 subnetting interview questions and answers in a multiple-choice format.
Question:
Your router has the IP address 172.16.2.1/23 on Ethernet 0. On the LAN interface, which of the following host IDs can be legitimate?
Options:
Answer Options:
Correct Answer: Option C
Q3. Question:
Which two statements describe the IP address 10.16.3.65/23?
Statements:
Answer Options:
Correct Answer: Option B
Q4. Question:
What is the broadcast address of the network 192.168.116.64 with mask 255.255.255.224?
Answer: 192.168.116.95
Q5. Question:
Which subnetwork’s first legitimate host is the node 172.20.225.111 with mask 255.255.255.128 a part of?
Answer: 172.20.225.1
Question:
The IP address 192.168.187.233/27 belongs to which valid host range?
Answer: 192.168.187.225 through 192.168.187.254
Question:
For CLASS A, the default network mask is:
Options:
Answer: Option A
Question:
For CLASS B, the default network mask is:
Answer: Option B
Question:
For CLASS C, the default network mask is:
Answer: Option C
Question:
What is the maximum number of IP addresses available for hosts on a subnet using the 255.255.255.224 mask?
Options:
Answer: Option C
Question:
To test the IP stack on your local host, which IP address should you ping?
Options:
Answer: Option A
Question:
You need to subnet a network into 5 subnets, each supporting at least 16 hosts. Which configuration will you choose?
Answer: Use a /28 subnet mask (255.255.255.240), which provides 16 subnets with 14 usable hosts each. This meets the requirement of at least 5 subnets with 16 hosts (including network and broadcast addresses)
Question:
What is the subnetwork number for a host with the IP address 172.16.66.0/21?
Answer: The subnet number is 172.16.64.0/21. This is determined by finding the subnet range, where 172.16.64.0 – 172.16.71.255 is the valid subnet block.
Question:
How many subnets and hosts per subnet can you get from the network 192.168.212.0 with mask 255.255.255.252?
Answer: A /30 subnet provides 64 (2⁶) subnets and 2 usable hosts per subnet (4 total addresses, minus 2 for network and broadcast).
Question:
What is the broadcast address of the network 192.168.72.64 with mask 255.255.255.192?
Answer: The broadcast address for the network 192.168.72.64/26 (mask 255.255.255.192) is 192.168.72.127. It is the last IP in the subnet range 192.168.72.64 – 192.168.72.127.
Question:
Which subnet does host 172.23.184.110 with mask 255.255.255.224 belong to?
Answer: 172.23.184.96
Question:
What is the network 192.168.79.48/28’s broadcast address?
Answer: 192.168.79.63
Question:
What is the last valid host on the subnetwork 172.19.219.160 with mask 255.255.255.240?
Answer: 172.19.219.174
Question:
What is the broadcast address of the network 172.18.107.0 with mask 255.255.255.224?
Answer: 172.18.107.31
Question:
Which subnetwork’s first legitimate host is the one to which node 172.31.148.112/22 belongs?
Answer: 172.31.148.1
Question:
What is the network 172.18.120.0/23’s broadcast address?
Answer: 172.18.121.255
Question:
What is the last valid host on the subnetwork 172.22.232.0 with mask 255.255.252.0?
Answer: 172.22.235.254
Question:
Which subnet does host 192.168.39.227 with mask 255.255.255.224 belong to?
Answer: 192.168.39.224
Question:
What is the broadcast address of the network 172.18.105.64 with mask 255.255.255.224?
Answer: 172.18.105.95
Question:
Which subnetwork is the first valid host in the one that contains the node 172.19.24.234 with mask 255.255.240.0?
Answer: 172.19.16.1
Question:
For the 172.16.0.0 network, you are creating a subnet mask. To achieve 80 subnets with up to 300 hosts per subnet, which subnet mask should you use?
Answer: 255.255.254.0
Question:
What is the subnetwork 172.16.22.0/24’s last operational host?
Answer: 172.16.22.254
Question:
Which host on the subnetwork 172.17.126.0/24 is the last one still in use?
Answer: 172.17.126.254
Q29. Subnets and Hosts from a /20 Network
Question:
How many subnets and hosts per subnet can be obtained from the network 172.28.0.0 with mask 255.255.240.0?
Answer: 16 subnets and 4094 hosts
Question:
What is the broadcast address of the network 10.230.32.0 with mask 255.255.240.0?
Answer: 10.230.47.255
Question:
What valid host range is the IP address 192.168.185.149/27 part of?
Answer: 192.168.185.129 through 192.168.185.158
Question:
What is the network 10.149.208.0/20’s broadcast address?
Answer: 10.149.223.255
Question:
Can you use mask 255.255.255.252 to extract the number of hosts and subnets from the network 192.168.129.0?
Answer: 64 subnets and 2 hosts
Question:
What is the first valid host on the subnetwork that the node 172.31.128.16 with mask 255.255.255.0 belongs to?
Answer: 172.31.128.1
Question:
How many hosts and subnets can you obtain from the 172.26.0.0/28 network?
Answer: 4096 subnets and 14 hosts
Question:
Which subnetwork’s first legitimate host is the node 172.30.241.75 with mask 255.255.240.0 a part of?
Answer: 172.30.240.1
Question:
What is the network 192.168.121.112’s broadcast address with mask 255.255.255.240?
Answer: 192.168.121.127
Question:
Which subnetwork’s first legitimate host is the node 172.25.85.103 with mask 255.255.254.0 a part of?
Answer: 172.25.84.1
Question:
What is the subnetwork 172.30.67.0/24’s last working host?
Answer: 172.30.67.254
Question:
What is the first valid host on the subnetwork that the node 172.31.242.158 with mask 255.255.255.192 belongs to?
Answer: 172.31.242.129
Question:
What is the last operational host for the subnetwork 172.29.4.0/23?
Answer: 172.29.5.254
Question:
How many subnets and hosts per subnet can you obtain from the network 172.16.0.0/23?
Answer: 128 subnets and 510 hosts
Question:
What is the last valid host on the subnetwork 172.22.94.144 with mask 255.255.255.240?
Answer: 172.22.94.158
Question:
For the 172.21.0.0 network, you require 100 subnets with up to 400 hosts each. Which subnet mask should you use?
Answer: 255.255.254.0
Question:
What is the broadcast address of the network 172.29.144.0/20?
Answer: 172.29.159.254
Question:
What is the range of valid hosts that includes the IP address 172.19.89.228/24?
Answer: 172.19.89.1 through 172.19.89.254
Question:
What is the subnetwork 172.28.99.0/24’s last working host?
Answer: 172.28.99.254
Question:
Which subnet does host 192.168.69.15 with mask 255.255.255.224 belong to?
Answer: 192.168.69.0
Question:
Which host is the first legitimate host in the subnetwork that contains the node 172.19.102.122/26?
Answer: 172.19.102.65
Question:
What is the first valid host for the network 172.122.18.0/24?
Answer: 172.122.18.1
Subnetting is a key part of working with networks. This guide is part of a CCNA course and includes 50 important questions and answers about subnetting. These questions help you learn how to break large networks into smaller parts.
They show you how to set up IP addresses and use subnet masks correctly. Using this guide, you can learn to create secure and fast networks. It is a helpful tool for students and anyone studying for CCNA, CCNP, or CCIE exams. By practicing these questions, you will build a strong base in networking. With clear steps and simple examples, you can become a confident network expert and become a pro.
