IPv4 Subnetting for Beginners: Step-by-Step Examples and Practice Questions
Introduction
IPv4 subnetting is an important networking skill for IT students and people preparing for certifications such as CompTIA Network+ and Cisco CCNA.
Subnetting divides an IP address range into smaller networks. It helps network administrators organize devices, manage IP addresses, and design networks efficiently.
In this beginner-friendly guide, you’ll learn how to identify a subnet mask, calculate a network address, and practice with an example.
1. What Is a Subnet Mask?
A subnet mask identifies which part of an IPv4 address represents the network and which part represents the host.
For example:
- IP address:
192.168.1.70 - CIDR prefix:
/26 - Subnet mask:
255.255.255.192
A /26 subnet contains 64 total IP addresses. In a traditional IPv4 subnet, two addresses are reserved for the network address and broadcast address, leaving 62 usable host addresses.
2. How to Find the Network Address
Consider this example:
IP address: 192.168.1.70/26
Step 1: Identify the subnet mask. The /26 prefix corresponds to 255.255.255.192.
Step 2: Calculate the block size: 256 − 192 = 64.
Step 3: The subnet ranges in the last octet begin at 0, 64, 128, and 192. Since 70 falls between 64 and 127, the network address is 192.168.1.64/26.
The broadcast address is 192.168.1.127, and the usable host range is 192.168.1.65 to 192.168.1.126.
3. Practice Question
You are given the IPv4 address 192.168.1.70/26. What is its network address?
- A.
192.168.1.0/26 - B.
192.168.1.64/26 - C.
192.168.1.70/26 - D.
192.168.1.128/26
Correct answer: B — 192.168.1.64/26
The block size is 64, and 70 belongs to the range 64–127.
4. Tips for Learning Subnetting
- Memorize common CIDR prefixes and subnet masks.
- Practice calculating block sizes.
- Learn to identify network and broadcast addresses.
- Solve practice questions before checking the answers.
- Review official certification exam objectives as part of your study plan.
Conclusion
Subnetting becomes easier with regular practice. Start with /24, /25, and /26 networks, then gradually move to more complex examples.
For more IT certification study resources and practice questions, visit https://examsteacher.com/
Top comments (1)
What subnetting topic do you find most challenging: calculating the block size, finding the network address, or identifying the usable host range? I’d love to hear what beginners are working on.