Create and configure virtual networks

Introduction

Imagine migrating a critical enterprise web application to the cloud, only to face network bottlenecks, unsegmented traffic, or exposure to the public internet. Designing a resilient, production-ready cloud environment always begins at the foundational layer: secure, scalable networking.

In this article, I demonstrate how to architect a modern cloud infrastructure blueprint using a Hub-and-Spoke topology in Microsoft Azure. This structural design isolates workloads, enforces security boundaries, and minimizes latency.

As a cloud professional, my focus isn't just on clicking buttons in the portal,it is on delivering architectural patterns that protect data, optimize costs, and align with the Azure Well-Architected Framework.

Scenario
Your organization is migrating a web-based application to Azure. Your first task is to put in place the virtual networks and subnets. You also need to securely peer the virtual networks. You identify these requirements.

• Two virtual networks are required, app-vnet and hub-vnet. This simulates a hub and spoke network architecture.
• The app-vnet will host the application. This virtual network requires two subnets. The frontend subnet will host the web servers. The backend subnet will host the database servers.
• The hub-vnet only requires a subnet for the firewall.
• The two virtual networks must be able to communicate with each other securely and privately through virtual network peering.
• Both virtual networks should be in the same region.

Skilling tasks

• Create a virtual network.
• Create a subnet.
• Configure vnet peering.

Note: To complete this lab you will need an Azure subscription with Contributor RBAC role assigned. In this lab, when you are asked to create a resource, for any properties that are not specified, use the default value.

Create hub and spoke virtual networks and subnets

An Azure virtual network enables many types of Azure resources to securely communicate with each other, the internet, and on-premises networks. All Azure resources in a virtual network are deployed into subnets within the virtual network.

1.Sign in to the Azure portal - https://portal.azure.com.

2.Search for and select Virtual Networks.

3.Select + Create and complete the configuration of the app-vnet.

This virtual network requires two subnets, frontend and backend.

Note:Leave all other settings as their defaults.

When finished select Review + create and then Create.

4.Create the Hub-vnet virtual network configuration. This virtual network has the firewall subnet.

5.Once the deployments are complete, search for and select your ‘virtual networks`.

6.Verify your virtual networks and subnets were deployed.

Configure a peer relationship between the virtual networks

Virtual network peering enables you to seamlessly connect two or more Virtual Networks in Azure.

1.Search for and select the app-vnet virtual network.

2.In the Settings blade, select Peerings.

3.+ Add a peering between the two virtual networks.

Note: Leave all other settings as their defaults. Select “Add” to create the virtual network peering.

4.Once the deployment completes, verify the Peering status is Connected.

Key takeaways

Here are the main takeaways:

• Azure virtual networks (VNets) provide a secure and isolated network environment for your cloud resources. You can create multiple virtual networks per region per subscription.
• When designing virtual networks make sure the VNet address space (CIDR block) doesn’t overlap with your organization’s other network ranges.
• A subnet is a range of IP addresses in the VNet. You can segment VNets into different size subnets, creating as many subnets as you require for organization and security within the subscription limit. Each subnet must have a unique address range.
• Certain Azure services, such as Azure Firewall, require their own subnet.
• Virtual network peering enables you to seamlessly connect two Azure virtual networks. The virtual networks appear as one for connectivity purposes.

Summary

This project isn't just about spinning up resources, it is a demonstration of secure, production-grade cloud architecture. By implementing this Hub-and-Spoke topology, I have successfully:

1.Enforced Strict Network Isolation: Segmented the application layer into dedicated frontend and backend subnets to implement a defense-in-depth security model.

2.Designed for Enterprise Scale: Established a central hub-vnet to allow seamless, future integration of centralized security appliances like Azure Firewall.

3.Optimized Performance & Security: Leveraged VNet Peering to ensure high-bandwidth, low-latency communication that remains entirely off the public internet.

I designed this infrastructure with a Zero-Trust mindset, ensuring that every deployment is scalable, compliant, and structurally aligned with enterprise security standards.