Azure Networking Basics: VNets, Subnets, NSGs Explained

Introduction: Why Networking Is the Hidden Skill Behind Every Cloud Job

When people start learning Azure, they often focus on virtual machines, web apps, or DevOps pipelines.

But behind every successful cloud deployment is something far more important:
Networking.

Every website that loads.
Every database query that runs.
Every API that responds.

All of it depends on how securely and efficiently systems are connected.

At NareshIT, students are taught a simple truth:
You can launch resources in the cloud in minutes.
But only strong networking skills can make them secure, scalable, and production-ready.

This blog will take you beyond definitions and help you understand how VNets, Subnets, and NSGs work together like a real digital city inside Microsoft Azure.

The Big Picture: What Is Azure Networking in Real Life?

Think of Azure as a massive digital country.

Inside this country, companies build:

• Offices (Virtual Machines)

• Data centers (Databases)

• Service counters (Web Apps and APIs)

• Highways (Connections between services)

Azure Networking defines:

• Who can talk to whom

• How data flows

• What is allowed

• What is blocked

Without proper networking, even the best cloud architecture becomes risky and unreliable.

Why Companies Care So Much About Cloud Networking

In real organizations, networking decisions impact:

• Security (protecting data and systems)

• Performance (how fast users get responses)

• Cost (data transfer charges and resource usage)

• Compliance (meeting industry and government rules)

• Scalability (handling growth without downtime)

That is why Azure networking skills are highly valued in:

• Cloud Engineer roles

• DevOps positions

• System Administration

• Cybersecurity careers

Understanding the Core Components

Azure networking is built around three foundational elements:

1. Virtual Networks (VNets) - The private cloud space

2. Subnets - The internal divisions inside that space

3. Network Security Groups (NSGs) - The security guards controlling traffic

Together, they create a secure, organized, and controlled cloud environment.

Virtual Networks (VNets): Your Private Cloud World

What Is a VNet in Simple Terms?

A Virtual Network is your own private network inside Azure.

Just like a company has its own internal office network, a VNet gives you:

• Private IP addresses

• Controlled access

• Isolated environment

• Secure communication between resources

By default, resources inside a VNet can talk to each other safely.

Why VNets Matter in Real Projects

Companies use VNets to:

• Separate production systems from testing systems

• Protect sensitive databases from the public internet

• Connect cloud systems with on-premise offices

• Control how applications communicate internally

A well-designed VNet is the foundation of secure cloud architecture.

How VNets Work Behind the Scenes

When you create a VNet, you define:

• An IP address range

• Location (region)

• Connectivity rules

Every resource placed inside the VNet receives a private IP address from that range.

This allows:

• Secure internal communication

• Controlled external access

• Network-level isolation

Subnets: Organizing Your Cloud Like a Smart City

What Is a Subnet?

If a VNet is a city, subnets are:

• Residential areas

• Business districts

• Industrial zones

Each area has a purpose and specific rules.

Why Subnets Are Important in Real Architecture

Subnets help:

• Separate public-facing systems from private systems

• Apply different security rules to different workloads

• Improve performance and management

• Support scaling and availability designs

For example:

• One subnet for web servers

• One subnet for application servers

• One subnet for databases

This structure makes cloud environments clean, secure, and professional.

Subnets and Security Design

Security is stronger when systems are grouped logically.

Databases should not sit in the same subnet as public web servers.

Subnets help you:

• Limit exposure

• Apply targeted security policies

• Reduce attack surfaces

This is a core concept in cloud security interviews.

Network Security Groups (NSGs): The Digital Security Guards

What Is an NSG?

An NSG is a set of rules that control network traffic.

It decides:

• What traffic is allowed

• What traffic is blocked

• From where

• To where

• On which port

Every rule is a decision point in your security system.

Why NSGs Are Critical in Production Environments

In real companies, security teams rely on NSGs to:

• Protect servers from hackers

• Allow only necessary services

• Block suspicious traffic

• Enforce compliance policies

A single wrong rule can expose an entire system.
That is why NSGs are treated as security policies, not just settings.

How NSGs Work Internally

Each NSG contains:

• Inbound rules (traffic coming in)

• Outbound rules (traffic going out)

Rules are evaluated in order of priority.
When traffic matches a rule, the action is applied:

• Allow

• Deny

This creates a layer of defense around your cloud systems.

Applying NSGs: Where Security Happens

NSGs can be applied to:

• Individual network interfaces (NICs)

• Entire subnets

Applying at subnet level protects all resources inside it.
This is common in enterprise designs.

How VNets, Subnets, and NSGs Work Together

Let’s walk through a real-world scenario.

Example: Hosting a Web Application

You want to deploy a secure web app.

You create:

• A VNet as your private cloud space

• A public subnet for web servers

• A private subnet for databases

• NSGs to control traffic

Rules might say:

• Allow internet traffic to web servers

• Allow web servers to talk to databases

• Block direct internet access to databases

This design protects sensitive data while keeping the app accessible.
This is real cloud architecture thinking.

Common Networking Design Patterns in Azure

1. Hub and Spoke Model
   One central VNet connects to multiple smaller VNets.
   Used in large enterprises for centralized security and connectivity.

2. Public-Private Network Design
   Public subnet for user-facing services.
   Private subnet for backend systems.

3. Hybrid Networking
   Cloud VNets connected to on-premise networks using VPN or ExpressRoute.

These patterns are often discussed in interviews and real cloud roles.

Why Networking Skills Boost Career Growth

Cloud professionals who understand networking:

• Debug issues faster

• Design secure systems

• Communicate better with security teams

• Handle enterprise-scale projects

This skill separates:

• Tool users

• From

• System architects

Common Beginner Mistakes

Many learners:

• Put everything in one subnet

• Allow all traffic in NSGs

• Ignore outbound rules

• Forget network planning

These mistakes are harmless in labs.
In production, they are dangerous.

Professional training focuses on design thinking, not just deployment steps.

How NareshIT Teaches Azure Networking

At NareshIT, students learn networking as:

• Architecture design

• Security planning

• Workflow mapping

• Real project implementation

Not just:
“Click here, create there.”

This prepares learners for:

• Cloud interviews

• DevOps roles

• Real enterprise projects

From Learner to Cloud Architect

The real shift happens when you stop asking:
“How do I create a VNet?”
And start asking:
“How should this system communicate securely?”

That mindset transforms your career path.

Frequently Asked Questions (FAQ)

1. Is Azure networking difficult for beginners?

It becomes simple when you think in real-world terms like cities, buildings, and security gates instead of technical jargon.

2. Do I need networking knowledge for DevOps roles?

Yes. CI/CD pipelines deploy into networks. Without understanding VNets and NSGs, troubleshooting becomes very difficult.

3. Can VNets connect to each other?

Yes. Using VNet peering, multiple networks can communicate securely.

4. Are NSGs enough for full security?

NSGs provide network-level security. Many companies also use firewalls and monitoring tools for layered protection.

5. What happens if I misconfigure an NSG?

You may block your own access or expose systems to the internet. Always plan and test rules carefully.

6. Is subnet design important for scalability?

Yes. Good subnet planning helps support future growth, high availability, and system expansion.

7. Are these topics asked in interviews?

Yes. Many cloud interviews include scenario-based questions on network design and security rules.

8. How long does it take to master Azure networking?

With hands-on projects and real architecture practice, learners usually become confident within a few months.

Final Thoughts: Networking Is the Backbone of the Cloud

Virtual Machines run your apps.
Databases store your data.
Pipelines deploy your systems.
But networking connects and protects everything.

When you master VNets, Subnets, and NSGs, you stop being someone who launches resources.
You become someone who designs secure cloud environments.

That is the difference between a cloud learner and a cloud professional.

Call to Action: Design Systems, Not Just Deploy Resources

If you want to learn Azure Networking the way real companies use it with security, architecture, and enterprise workflows focus on building thinking skills, not just technical steps.

At NareshIT, students learn how cloud systems work in the real world  not just in labs. Explore our Azure training programs to master these essential skills. For specialized training that includes these networking fundamentals, check out our Azure Administrator (AZ-104) course and start designing networks that power real businesses, not just virtual machines.