What is subnetting? well If you’ve ever wondered how devices communicate across networks without chaos, the answer lies in subnetting. At first it might sound like a highly technical term reserved for network engineers, but the truth is it’s just a clever way to break a large network into smaller, more manageable ones. example on this, a network on an ip range of192.168.1.0 can be broken down into 5, 6,7 or even 10 subnets.

In this blog, you’ll learn what sub-netting is, why it matters, how it works, and how to calculate subnets yourself. By the end, you’ll be confident enough to read an IP address, understand subnet masks, and even perform basic sub-netting tasks.

What is Subnetting?

Simple definition

Subnetting is the process of dividing one large network into multiple smaller networks called subnets, By breaking down a single IP address to multiple smaller networks.

Think of it like dividing a big piece of land into plots. Instead of everyone building on one huge land where confusion reigns, you cut it into plots so each person knows where their boundary starts and ends.

What is CIDR Notation?, CIDR stands for Classless Inter-Domain Routing. As the name suggests, it is a classless method of allocating IP addresses and routing traffic across the internet.

ALSO READ : What is an IP Address? A Beginner’s Guide to IPv4 & IPv6

Technical definition

Subnetting takes an IP address and “splits” it into two parts:

The network portion – identifies the overall network.

The host portion – identifies individual devices within that network.

By subnetting, you ensure devices are grouped efficiently and data reaches the right destination without wasting IP addresses.

Why is Subnetting Important?

Subnetting plays a huge role in modern networking, keeping in mind that IPV4 only has 4.3 billion IP address that cannot handle the rapid technology growth, its of very importance to split IPS into smaller network so as to handle the internet in organized manner. Here is the reason why subnetting is important;

Efficient use of IP addresses – prevents waste of valuable addresses.

Improved performance – smaller networks reduce congestion.

Better security – traffic can be isolated between subnets.

Simplified management – troubleshooting is easier in smaller networks.

Scalability – you can expand a network in an organized way.

How to Subnet

Well, before we tackle the elephant in the room, it importance to know all classes of ip address, this way we will be able to decide the ip and the subnet mask that we will be working with

Class	IP Range	Default Subnet Mask	CIDR Notation
A	1.0.0.0 – 126.255.255.255	255.0.0.0	/8
B	128.0.0.0 – 191.255.255.255	255.255.0.0	/16
C	192.0.0.0 – 223.255.255.255	255.255.255.0	/24
D	224.0.0.0 – 239.255.255.255	Not Defined (Multicast)	N/A
E	240.0.0.0 – 255.255.255.255	Reserved	N/A

How Subnetting Works (Step-by-Step)

Let’s break down subnetting into a clear process:

• Start with a network address choose any for me i will go with 192.168.1.0/24.
• Decide how many subnets/how many small netwok you need.
• Borrow bits from the host portion to create more network IDs.
• Each new subnet gets its own range of IP addresses.
• Devices inside each subnet can communicate locally, but to reach other subnets, they need a router.

Example

• Original network: 192.168.1.0/24 (256 IPs)
• If we subnet into 4, we borrow 2 bits.
• New subnets:
  • 192.168.1.0/26 → 62 hosts
  • 192.168.1.64/26 → 62 hosts
  • 192.168.1.128/26 → 62 hosts
  • 192.168.1.192/26 → 62 hosts

Now instead of one giant network, you have 4 neat sub-networks.

Subnetting Formulas You Must Know

To subnet, you’ll use these formulas:

• Number of Subnets = 2ⁿ (where n = borrowed bits)
• Hosts per Subnet = 2ʰ – 2 (where h = host bits, subtract 2 for network & broadcast)

Example:

• Subnet mask = /26 → means 6 host bits.
• Hosts = 2⁶ – 2 = 62 per subnet.

FAQs About Subnetting

Q1: What IP address should I use?
Use private IP ranges (e.g., 192.168.x.x, 10.x.x.x) for home or office networks. Public IPs are assigned by ISPs.

Q2: How do IP addresses work?
They identify devices on a network and ensure data travels from sender to the correct receiver.

Q3: Can IP addresses be changed?
Yes. You can manually assign an IP or let your router assign one automatically (DHCP).

Q4: Why do we need IP addresses?
Without IPs, devices wouldn’t know where to send or receive data on the internet.

Q5: Can IP addresses be hacked?
Hackers can’t “hack” an IP directly, but they can use it to target your device if it’s unprotected. Always use firewalls and strong passwords.

Q6: What are the classes of IP addresses?

• Class A: Huge networks (1.0.0.0 – 126.0.0.0).
• Class B: Medium networks (128.0.0.0 – 191.255.0.0).
• Class C: Small networks (192.0.0.0 – 223.255.255.0).