Managing Virtual Networks in Azure: Essential Knowledge for AZ-104

Azure Virtual Networks (VNets) are the cornerstone of networking in Microsoft Azure. For those preparing for the AZ-104: Microsoft Azure Administrator certification, understanding how to manage VNets is crucial. This blog will explore key concepts, practical applications, and tips to master Azure Virtual Networks, equipping you for both the exam and real-world scenarios.

What is a Virtual Network in Azure?

Azure Virtual Networks allow resources like virtual machines (VMs), databases, and app services to communicate securely with each other, on-premises networks, and the internet. VNets provide isolation, segmentation, and security within Azure’s infrastructure, functioning much like traditional on-premises networks.

Core Concepts of Azure VNets

Before diving into management tasks, let’s review some foundational concepts:

1. Address Space

Each VNet requires an IP address range defined using the Classless Inter-Domain Routing (CIDR) format. This address space is divided into subnets, which enable efficient IP address management.

2. Subnets

Subnets divide a VNet into smaller segments to organize and secure resources. Each subnet has its own IP range within the VNet's address space.

3. Network Security Groups (NSGs)

NSGs act as a firewall for VNets, controlling inbound and outbound traffic to resources. They consist of rules defined by priority, source/destination, and protocol type.

4. Virtual Network Peering

Peering connects two VNets, allowing resources to communicate as if they were part of the same network. It’s a cost-effective alternative to traditional VPNs.

5. Azure DNS and Private DNS Zones

DNS in Azure resolves domain names to IP addresses within your VNet, ensuring seamless communication between resources.

Key Tasks for Managing VNets in AZ-104

1. Creating a VNet

To create a VNet, follow these steps:

- Go to the Azure Portal.

- Navigate to Create a Resource > Networking > Virtual Network.

- Configure the VNet by specifying the address space, subnets, and region.

> Tip : Use address spaces that do not overlap with on-premises networks to avoid conflicts during hybrid network integration.

2. Configuring Subnets

- Subnets are critical for segmenting traffic within a VNet.

- Create multiple subnets to separate application tiers (e.g., front-end, back-end, and database).

- Assign NSGs to secure subnets with role-specific traffic rules.

3. Setting Up NSGs

NSGs can be associated with either a subnet or an individual NIC (Network Interface Card). When configuring NSG rules:

- Use priority numbers to define the order in which rules are applied (lower numbers have higher priority).

- Specify source/destination IP ranges and ports for precise traffic control.

- Test NSG rules to ensure they allow necessary traffic while blocking unauthorized access.

4. Implementing VNet Peering

For seamless communication between VNets:

- Navigate to Peerings under the VNet settings in the Azure Portal.

- Add a peering, specifying the remote VNet.

- Enable options like Allow Gateway Transit for hybrid scenarios or Use Remote Gateways to utilize an existing gateway in another VNet.

5. Integrating with On-Premises Networks

Hybrid networking connects your on-premises infrastructure to Azure. The two primary methods are:

- VPN Gateway : Establish a secure, encrypted connection using a site-to-site VPN.

- ExpressRoute : A dedicated, high-speed private connection for large-scale deployments.

6. Monitoring and Diagnosing VNet Traffic

Effective monitoring ensures optimal performance and security. Use tools like:

- Azure Network Watcher : Diagnose connection issues, capture packets, and review network topology.

- NSG Flow Logs : Analyze traffic flow for auditing or troubleshooting purposes.

- Metrics and Alerts : Set up custom alerts for unusual traffic patterns or service disruptions.

VNet Best Practices for the AZ-104 Exam and Real-World Use

1. Plan Address Spaces : Use non-overlapping IP address ranges to avoid conflicts in hybrid or multi-VNet setups.

2. Segmentation : Always segment VNets using subnets to isolate workloads for better security and performance.

3. Automate with ARM Templates : Define VNets and their configurations using Azure Resource Manager (ARM) templates to ensure consistency across deployments.

4. Implement Security Layers : Combine NSGs with Azure Firewall or Application Gateway for enhanced security.

5. Test Configuration Changes : Use Azure Network Watcher’s connectivity checks and troubleshooting tools to validate network configurations.

Key Exam Tips for AZ-104 VNet Topics

- Understand Scenarios : Exam questions often present scenarios requiring you to design or troubleshoot VNet configurations. Focus on understanding use cases for NSGs, peering, and hybrid connectivity.

- Hands-On Practice : Spend time in the Azure Portal creating and managing VNets. Practical experience is essential to confidently answer scenario-based questions.

- Review Microsoft Documentation : The official Microsoft Learn modules provide up-to-date information and interactive labs tailored to the AZ-104 exam.

Conclusion

Managing Virtual Networks in Azure is a critical skill for Azure Administrators. For AZ-104, mastering VNets involves understanding their architecture, creating secure configurations, and troubleshooting connectivity issues. By practicing hands-on in the Azure Portal and reviewing the concepts discussed here, you’ll not only excel in your certification exam but also gain the confidence to handle complex networking tasks in real-world environments.

Happy learning, and best of luck on your journey to becoming a certified Azure Administrator!