DEV Community: Fatunde Adekunle

Designing a Secure Three-Tier Azure Network Infrastructure

Fatunde Adekunle — Thu, 09 Jul 2026 12:27:53 +0000

In this project, we will learn how to design a secure Azure Virtual Network with segmented subnets, deploy Linux virtual machines, configure Network Security Groups (NSGs), implement User-Defined Routes (UDRs), and validate secure communication between application tiers.

Step 1: Create the Virtual Network

a. Sign in to the Azure Portal.

b. Search for Virtual Networks.

c. Click Create.

Assign choice values to the tabs
Basics

Resource Group: Lab-RG
Name@ Production-VNet
Region@ West US 3 (Choose your preferred region)

Address Space:

10.0.0.0/16

//Create the following subnets:

Click on the "+ Add a subnet" to add the following subnet.

Subnet Address Range
Frontend-subnet 10.0.1.0/24
Backend-subnet 10.0.2.0/24
Database-subnet 10.0.3.0/24

Click on "Review + Create".

Click on Add to add the subnet

//Each subnet is created independently by repeating the process.

After validation has passed, press the "Create " button to create the VNet

Check:

On the left pane in your VNet, click on "settings" and then "subnets"

Step 2: Create NSGs

Create two NSGs:

Frontend-NSG

Search:

Network Security Groups

Create:

a. Fill in the values in the "Basics" tab
b. Review + create

After validation has passed, click Create

Go to resource

Repeat the same steps for the Backend-NSG

Backend-NSG

Search:

Network Security Groups

Create:

a. Fill in the values in the "Basics" tab
b. Review + create

After validation has passed, click Create

Go to resource

Step 3: Configure Frontend NSG Rules

Attach Frontend-NSG to Frontend-subnet.

a. In the "Subnets" tab under the "Settings" blade in the left pane, click "Frontend-subnet".

b. Go to the "Network Security Group" under the "Edit subnet".
c. Click on the drop-down arrow and select "Frontend-NSG"

Add inbound rules:

Priority Source Port Protocol Action
100 Internet 80 TCP Allow
110 Internet 443 TCP Allow
120 Your IP 22 TCP Allow
4096 Any Any Any Deny

In the "Frontend-NSG", click on the "Inbound security rules" under the "Settings" blade in the left pane.
Click "Add".

Provide the necessary details

*SSH *

Keep using the "Add" button until you are done setting the rules.

HTTP

HTTPS

Custom

//Refer to the table above for the appropriate values.

This allows:

HTTP
HTTPS
SSH from your workstation only

Step 4: Configure Backend NSG Rules

Attach Backend-NSG to Backend-subnet.

a. In the "Subnets" tab under the "Settings" blade in the left pane, click "Backend-subnet".

b. Go to the "Network Security Group" under the "Edit subnet".
c. Click on the drop-down arrow and select "Backend-NSG"

Create inbound rule:

Priority Source Source Address
100 IP Addresses 10.0.1.0/24

Destination: Any

Protocol: Any

Action: Allow

Leave the default DenyAllInbound rule.

Result:

✅ Frontend subnet can access Backend VM

✅ Internet cannot access Backend VM

Step 5: Deploy Frontend VM

Create a Linux VM.

Recommended:

Setting Value
Name frontend-vm
Image Ubuntu 24.04 LTS
Size B1s
Authentication SSH Key

Networking:

Setting Value
Virtual Network Production-VNet
Subnet Frontend-subnet
Public IP Create New
NSG Frontend-NSG

Download the private key and create the resource

Create VM.

Repeat the same step to create the Backend VM.

Step 6: Deploy Backend VM

Create another Linux VM.

Setting Value
Name backend-vm
Image Ubuntu 24.04 LTS
Size B1s

Networking:

Setting Value
VNet Production-VNet
Subnet Backend-subnet
Public IP None
NSG Backend-NSG

Create VM.

//Do not forget to download the private key

Step 7: Verify Public Access

Make sure you log in to your Azure portal from your Azure CLI/Git Bash. (Git Bash was the CLI used in this project)

Frontend VM

Obtain Public IP:

Type the command below in the terminal:
ssh azureuser@
ssh -i "C:\Users***l\Downloads\frontend-vm_key.pem" azureuser@20.168.66.216

ssh → The command to start an SSH session.

-i "C:\Users***l\Downloads\dev_key.pem" → Specifies the identity file (private key) used for authentication.

On Windows, make sure the path is correct and the .pem file has proper permissions.

azureuser@20.168.66.216 → Connects to the server at IP 20.168.66.216 using the username azureuser.

Type yes and enter

Should connect successfully.

Backend VM

Try connecting to the backend VM using the same syntax. But this time around, use the private key for the backend VM you downloaded:

ssh azureuser@

Expected result should be:

Connection timed out

because:

No Public IP
NSG blocks Internet traffic

Requirement satisfied.

Step 8: Test Frontend → Backend Connectivity

SSH into Frontend VM.

Find Backend private IP:

Example:

10.0.2.4

Install ping utility:

sudo apt update

sudo apt install iputils-ping -y

Ping Backend:

ping 10.0.2.4

Expected:

64 bytes from 10.0.2.4

Requirement satisfied.

Step 9: Install a Web Server on Frontend
sudo apt update
sudo apt install nginx -y

Enable:

sudo systemctl enable nginx

sudo systemctl start nginx

Browse:

Type http://20.168.66.216

You should see the Nginx welcome page.

Requirement satisfied:

✅ Frontend VM reachable via Public IP.

Step 10: Create User Defined Route (UDR)

Search:

Route Tables

Create:

Frontend-Backend-RT
Add Route
Field Value
Route Name InternalRoute
Address Prefix 10.0.2.0/24
Next Hop Type Virtual Network

Associate Route Table with:

Frontend-subnet

Result:

Traffic destined for Backend subnet remains inside Azure's virtual network routing and never traverses the Internet.

Validation Checklist
Requirement Status
Create VNet ✅
Frontend subnet ✅
Backend subnet ✅
Database subnet ✅
Linux VM in Frontend ✅
Linux VM in Backend ✅
HTTP/HTTPS allowed to Frontend ✅
Backend accepts traffic only from Frontend subnet ✅
Internet blocked from Backend ✅
Frontend has Public IP ✅
Backend has no Public IP ✅
Frontend can ping Backend ✅
UDR configured ✅

CREATE AND CONNECT TO A WINDOWS VIRTUAL MACHINE (VM) ON AZURE

Fatunde Adekunle — Wed, 11 Feb 2026 03:00:15 +0000

What is Virtual Machine?
A software-based computer that operates inside a real computer is called a virtual machine (VM). Although it shares hardware with a "host" system, it functions as a separate physical machine with its own operating system (OS), processor, memory, and storage.

How it works
A piece of software known as a hypervisor, or virtual machine monitor, is necessary for virtual machines. By serving as a traffic cop and allocating resources (such as CPU and RAM) to ensure that each virtual machine operates in a separate, isolated environment, the hypervisor sits between the actual hardware and the virtual machines.

Two main categories of hypervisors exist:

Type 1 (bare-metal): Utilises the actual hardware for operation. These are commonly seen in cloud environments and huge data centres (e.g., VMware ESXi, Microsoft Hyper-V).

Type 2 (Hosted): Functions as an application running on top of an OS, such as macOS or Windows. These are frequently used for personal usage (e.g., VMware Workstation, Oracle VirtualBox).

Important Elements
The actual physical computer or server that supplies the underlying hardware resources is known as the host machine.

The virtual environment (or several environments) operating on top of the host is known as the guest virtual machine.

The specialised software layer known as the hypervisor is responsible for creating and managing virtual machines (VMs) by assigning CPU, RAM, and disc space to each one.

Principal Virtual Machine Types
System virtual machines (VMs) allow you to run a complete operating system, such as Linux, on a Windows computer by simulating an entire computer system.

Process virtual machines (VMs) are made to run a single program in a separate setting. The Java Virtual Machine is a well-known example (JVM).

What Makes a Virtual Machine Useful?
Security & Isolation: Programmes operating within virtual machines are unable to disrupt the host system. They are therefore perfect for securely testing new apps or dubious data.

Run Multiple OSs: On a single physical device, you can run multiple operating systems (such as Windows, macOS, and Linux) concurrently.
Resource Efficiency: Businesses can save money on hardware and energy by combining multiple "virtual" servers onto a single physical server by using virtual machines (VMs).
Snapshots & Recovery: A virtual machine's present state can be "snapshot"ed. You can quickly return to that earlier condition if something breaks.

Popular VM Software
Popular tools include:

Oracle VirtualBox: A free, open-source option for personal use.
VMware Workstation: A robust choice for both personal and enterprise use.
Microsoft Hyper-V: Built into professional versions of Windows.

How to Deploy a Virtual Machine (VM)

https://portal.azure.com/

On the homepage, search for “Virtual Machines“ in the search box.

Click on “Create”

Choose the “Azure Virtual Machine“ option

Configure the “Basics“

Subscription: Choose your Azure subscription.

Resource Group: Create a new resource group or select an existing one to organize your resources.

VM Name: Provide a unique name for your VM.

Region: Choose a region for the VM, such as East US or West Europe.

Availability Options: Select any required options like high availability.

Image: Select the operating system (Windows) for the VM.

Administrator Account: Set up the username and password and RDP for logging into the VM.

Click on the “Review/Create“ button to create your virtual machine

Wait for “validation“

Click on “create.“

Once “deployment“ is complete, click on the “Go to resource“ button

Click on “connect“ to connect to your VM

Download “RDP File“ to your physical computer

Right-click on the downloaded file in your local drive and click “Connect“

Click “connect“ on the dialog box that pops up

Put in your login credentials (your username and password) used to create the VM

Click Yes and wait for the VM to be launched.

Unpacking the Foundation: Understanding Azure's Core Architectural Components

Fatunde Adekunle — Wed, 26 Nov 2025 13:30:16 +0000

Introduction
Ever wondered what makes a massive cloud platform like Microsoft Azure tick? While the sheer number of services can seem daunting, at its heart, Azure is built upon a few fundamental architectural components that provide its incredible scale, resilience, and flexibility. Understanding these building blocks is key to effectively designing and deploying solutions in the cloud.

Let's dive into the core components that form the backbone of Azure.

1. Regions and Availability Zones: Global Reach, Local Resilience

Imagine a global network of interconnected data centers. That's essentially what Azure provides, organized into Regions and Availability Zones.

Azure Regions: A region is a geographical area that contains one or more data centers. Think of them as massive, independent data center hubs located across the globe (e.g., "East US," "West Europe," "Southeast Asia"). Choosing the right region is crucial for data residency, compliance, and minimizing latency for your users.

Availability Zones (AZs): Within many Azure Regions, you'll find Availability Zones. These are physically separate locations within an Azure region, each with independent power, cooling, and networking. If one zone experiences a failure (like a power outage), your applications and data in other zones within the same region can continue to operate. This provides high availability and fault tolerance, making your applications more robust.

Why it matters: Regions provide global presence, while Availability Zones offer critical redundancy within a region, ensuring your services stay online even during localized disruptions.

2. Resources and Resource Groups: Organizing Your Cloud Estate

Once you start deploying services in Azure, you'll be creating Resources.

Azure Resources: Simply put, any instance of a service you create in Azure is a resource. A virtual machine, a storage account, a web app, a database – these are all individual resources.
Resource Groups: Managing dozens or hundreds of individual resources can quickly become chaotic. That's where Resource Groups come in. A resource group is a logical container that holds related resources for an Azure solution. For example, you might put all the VMs, databases, and network components for a specific application into a single resource group. This allows you to manage their lifecycle together – you can deploy, update, and delete them as a single unit, and apply common policies and permissions.

Why it matters: Resource groups bring order to your cloud environment, simplifying management, billing, and access control.

3. Azure Resource Manager (ARM): The Control Plane for Everything
**
How do you interact with and manage all these resources? Through the **Azure Resource Manager (ARM).

ARM is the management layer that enables you to create, update, and delete resources in your Azure subscription. Whether you're using the Azure portal, PowerShell, Azure CLI, or REST APIs, you're interacting with ARM. It provides a consistent interface and capabilities across all Azure services, allowing for declarative deployment (defining what you want, and ARM makes it happen) and robust access control.

Why it matters: ARM is the central nervous system of Azure management, providing a unified way to control and automate your cloud infrastructure.

4. Subscriptions: Your Account Boundary

Finally, all your resources live within an Azure Subscription.

Azure Subscriptions: A subscription serves as a billing boundary and a unit of management. All your Azure resources are provisioned within a subscription, and usage is billed against it. You can have multiple subscriptions, often used to separate environments (e.g., Development, Staging, Production) or departments within an organization.

Why it matters: Subscriptions define your financial and administrative boundaries within Azure, enabling clear cost tracking and organizational separation.

Bringing It All Together

To visualize it:

You have a Subscription, which contains multiple Resource Groups. Each Resource Group holds related Resources. These resources are deployed into specific Regions, leveraging Availability Zones for high availability. All of this is managed and orchestrated through the Azure Resource Manager.

Understanding these core architectural components is the first step towards building efficient, scalable, and resilient solutions on Microsoft Azure. They are the bedrock upon which all the amazing Azure services are built, providing the structure and control you need to master the cloud.

How to Create an Azure Account on Azure Portal

Fatunde Adekunle — Tue, 25 Nov 2025 15:12:42 +0000

*Title:
Getting Started with Azure: Creating Your First Account on the Azure Portal
*

Introduction
Cloud computing is transforming how we build and deploy applications. Microsoft Azure is one of the leading cloud platforms, offering services for hosting, storage, AI, and more. But before you can explore its powerful features, you need an account.

In this post, I’ll walk you through the simple steps to create your first Azure account using the Azure Portal.

Step 1: Go to the Azure Portal

Open your browser and navigate to https://portal.azure.com.
You’ll see the Azure sign-in page with options to sign in or create a new account.

Step 2: Click on “Create an Account.”

Select “Create one!” If you don’t already have a Microsoft account.
You can use an existing email (Gmail, Yahoo, Outlook) or create a new Outlook email.

Step 3: Enter Your Details

Provide your name, email, and password.
Verify your email address with a code sent to your inbox.

Step 4: Add Security Information

Enter your phone number for identity verification.
Choose your country/region.

Step 5: Provide Payment Information

Azure requires a credit/debit card for verification, but you won’t be charged for the free trial.
Microsoft offers $200 free credit for the first 30 days and access to free services for 12 months.

Step 6: Agree to Terms and Finish

Review the Microsoft Azure agreement.
Click Sign Up to complete the process.

🎯 What You Get After Signing Up

Access to the Azure Portal Dashboard.
$200 in free credits to explore services.
Free tier services like Azure App Service, Azure Functions, and Azure Blob Storage.

Conclusion
Creating an Azure account is the first step toward unlocking the world of cloud computing. With your account ready, you can start experimenting with virtual machines, databases, and serverless apps. In my next post, I’ll show you how to deploy your first web app on Azure.

💡 Engagement Prompt:

Have you tried creating an Azure account before? What was your first project after signing up?