Creating a virtual network (VNet) with multiple subnets in Azure is essential for organizing and securing your cloud resources. This blog will walk you through creating a VNet with four subnets using the address space 192.148.30.0/26.

Step 1: Understanding the Address Space
The CIDR notation 192.148.30.0/26 means:

Network address: 192.148.30.0
Subnet mask: 255.255.255.192
Total number of IP addresses: 64 (2^6)
We need to divide this address space into four subnets. Each subnet will have a /28 prefix, giving us 16 IP addresses per subnet (2^4).

Step 2: Calculating the Subnets
Here's how we can divide the 192.148.30.0/26 address space into four /28 subnets:

Subnet 1: 192.148.30.0/28

Network address: 192.148.30.0
Broadcast address: 192.148.30.15
Usable IP range: 192.148.30.1 to 192.148.30.14

Subnet 2: 192.148.30.16/28

Network address: 192.148.30.16
Broadcast address: 192.148.30.31
Usable IP range: 192.148.30.17 to 192.148.30.30

Subnet 3: 192.148.30.32/28

Network address: 192.148.30.32
Broadcast address: 192.148.30.47
Usable IP range: 192.148.30.33 to 192.148.30.46

Subnet 4: 192.148.30.48/28

Network address: 192.148.30.48
Broadcast address: 192.148.30.63
Usable IP range: 192.148.30.49 to 192.148.30.62

1. Create the Virtual Network

Log in to the Azure Portal

Open your web browser and go to the Azure Portal.

Create a New Resource Group

Navigate to Resource groups.

Click on Create and fill in the required details:

Resource group name: Give your resource group a name
Region: Select your preferred region
Click Review + create and then Create.
Create the Virtual Network

Navigate to the Virtual network page
Click on virtual network

Click on create

Fill in the required details:
Name: Name of choice
Subscription: Select your subscription
Resource group: MyResourceGroup
Region: Select the same region as your resource group
Click on next until IP addresses"

2. Configure IP address and Subnets##

Enter the IPV4 address for the virtual network which is 192.148.30.0/26, and from this network, there are going to be 64 addresses. Click on Add a Subnet

The subnet address range will be
Subnet-1 :192.148.30.0/28 - 192.148.30.15/28.
Subnet-2 :192.148.30.16/28 - 192.148.30.31/28.
Subnet-3 :192.148.30.32/28 - 192.148.30.47/28.
Subnet-4 :192.148.30.48/28 - 192.148.30.63/28.

Click on review + create

Click on Create

When Your deployment is complete, click on Go to resource

To have a view of the subnets created, click on Settings on the left pane and then on Subnets

Creating a virtual network (VNet) with multiple subnets is crucial for organizing and securing your Azure resources. Following the steps above, you can set up a VNet with subnets using an address space. VNets help improve organization, enhance security, boost performance, simplify management, and enable seamless connectivity between your on-premises and cloud resources. This setup will make everything neat, secure, and easy to manage, ensuring your cloud infrastructure runs smoothly and efficiently with Azure VNets!