CCNA Class C Subnetting Questions – Blog

CCNA Class C Subnetting Questions

Subnetting is a crucial concept in networking, especially for those pursuing Cisco Certified Network Associate (CCNA) certification. Understanding subnetting is essential for network engineers as it allows them to efficiently allocate IP addresses and manage network resources. In this blog post, we will explore some challenging Class C subnetting questions to help you improve your subnetting skills.

Question 1:

Given a Class C network address 192.168.1.0/24, divide it into subnets with a maximum of 20 hosts each. How many subnets are created, what are their respective subnet ranges, and what are the valid host addresses for each subnet?

To find the number of subnets, we can use the formula:

Number of subnets = 2^(n) = 2^(ceil(log2(hosts + 2)))

Using this formula, we need to determine the number of host bits required to accommodate 20 hosts:

Number of host bits = ceil(log2(20 + 2)) = ceil(log2(22)) = 5

Therefore, we require 5 host bits, resulting in 2^5 = 32 subnets. The subnet ranges and valid host addresses for each subnet are as follows:


Subnet Subnet Range Valid Host Addresses
Subnet 1 192.168.1.0/29 192.168.1.1 – 192.168.1.6
Subnet 2 192.168.1.8/29 192.168.1.9 – 192.168.1.14
Subnet 3 192.168.1.16/29 192.168.1.17 – 192.168.1.22
Subnet 4 192.168.1.24/29 192.168.1.25 – 192.168.1.30
Subnet 5 192.168.1.32/29 192.168.1.33 – 192.168.1.38
Subnet 6 192.168.1.40/29 192.168.1.41 – 192.168.1.46
Subnet 7 192.168.1.48/29 192.168.1.49 – 192.168.1.54
Subnet 8 192.168.1.56/29 192.168.1.57 – 192.168.1.62
Subnet 9 192.168.1.64/29 192.168.1.65 – 192.168.1.70
Subnet 10 192.168.1.72/29 192.168.1.73 – 192.168.1.78
Subnet 11 192.168.1.80/29 192.168.1.81 – 192.168.1.86

By using this subnetting scheme, we can create 32 subnets with a maximum of 20 hosts each.

Question 2:

Consider a Class C network address 192.168.0.0/23. You need to create multiple subnets with different sizes. Calculate the number of subnets, their subnet ranges, and the maximum number of hosts that can be accommodated in each subnet.

To determine the number of subnets, we need to find the number of subnet bits. In this case, the subnet mask is /23, which means we have 9 host bits remaining:

Number of host bits = 32 - 23 = 9

Now, we can find the number of subnets:

Number of subnets = 2^(9) = 512 subnets

Since we have 9 host bits, we can create 512 subnets. The subnet ranges and the maximum number of hosts for each subnet are as follows:


Subnet Subnet Range Maximum Number of Hosts
Subnet 1 192.168.0.0/25 126 hosts
Subnet 2 192.168.0.128/25 126 hosts

By utilizing this subnetting scheme, we can create 512 subnets with different sizes within the Class C network address 192.168.0.0/23.

Question 3:

… [continue with more questions and explanations]

Leave a Comment