Optimizing Azure Virtual Network Configurations for the AZ-104 Exam

As organizations and businesses migrate to cloud infrastructure, especially Microsoft Azure, learning Azure and Azure networking is very important for cloud administrators to advance their careers in the Azure cloud. The AZ-104 Microsoft Azure Administrator certification exam assesses your ability to manage Azure core services, and one of the most critical areas covered is Azure networking configurations. For Azure Administrators, it’s very important to understand how to optimize virtual networks, configure security, and ensure network performance.

In this blog, we’ll learn how to optimize Azure Virtual Network (VNet) configurations, focusing on key components such as virtual subnets, Azure network security groups (NSGs), and network performance optimization. This guide will provide some best practices to help you succeed if you’re preparing for the Microsoft Azure Administrator AZ-104 exam.

Overview of Azure Virtual Network

An Azure Virtual Network is a core service of Azure that allows you to secure communication between different Azure resources, other VNets, and on-premises environments. It manages IP addressing, subnet segmentation, and traffic management to provide a secure and scalable network infrastructure for Azure services.

VNets allow you to define private IP spaces, create subnets, and implement security controls such as Network Security Groups. They also enable low-latency connectivity via VNet peering, which connects VNets across different regions without VPNs.

Azure Virtual Networks (Source)

Components of an Azure Virtual Network

The following are some important components of the Azure virtual network:

• Subnets: Separate workloads, improve security, and optimize resource management by segmenting a VNet.
• Network Security Groups (NSGs): NSGs control subnet or VM-level inbound and outbound traffic with rules.
• Route Tables: Manage VNet traffic with system or user-defined routes.
• IP Addressing: Use private IPs for internal and public IPs for external traffic.
• VNet Peering: Connect VNets for high-bandwidth and low-latency communication.

Also read: Top 22 Microsoft Azure Interview Questions and Answers

Understanding Virtual Subnets in Azure

Subnets are subdivisions of a Virtual Network in Azure that help organize and isolate cloud resources. Splitting a VNet into subnets allows you to manage network traffic, enforce security, and optimize performance for various workloads. Each subnet can be associated with a specific resource, allowing for more efficient management and security settings.

with subnets, you can assign IP ranges and use security controls like Network Security Groups (NSGs) to regulate traffic more granularly. This micro-segmentation allows you to apply different security and access controls to different network parts.

Optimizing Subnet Design

Azure subnets must be carefully planned for security and scalability. The following are some best practices you can use to optimize your subnet design:

• Address Space Allocation: Avoid overlap when connecting to on-premises networks or other VNets by carefully planning your subnet’s IP ranges. Ensure your subnet sizes match your future growth needs because Azure uses CIDR notation to define address spaces.
• Segmenting Workload: Separate web servers, databases, and management services with subnets. Each subnet can have its own security and routing policies, which improves security and performance.
• Subnet Security Boundaries: Configure subnet-level NSG rules for inbound and outbound traffic. For instance, you can limit database subnet communication to the web server subnet.
• Subnets and Availability Zones: When planning high availability, spread subnets across Availability Zones for resilience. This ensures that subnet services can continue after a zone failure.

Subnet Delegation and Service Integration

Azure also supports subnet delegation, which assigns a subnet to a specific Azure service, such as Azure App Service Environment (ASE) or Azure Kubernetes Service (AKS). This feature allows seamless integration and automatic configuration, ensuring the service performs efficiently within the subnet.

Network Performance Optimization in Azure

Network performance is crucial for Azure application efficiency and reliability. Poor cloud network performance can cause high latency, low throughput, and low application availability, affecting user experience. Optimizing network performance is important for Azure administrators to manage costs and provide seamless user experiences.

The AZ-104 exam requires knowledge of Azure’s VNet Peering, ExpressRoute, VPN Gateways, and Accelerated Networking features and tools that improve network performance. And, we can see how these features work in the Azure cloud environment. 

Virtual Network Peering

VNet Peering is a feature that connects two or more Azure Virtual Networks, either in the same or different regions. Peering establishes a low-latency, high-bandwidth connection between VNets that does not require a VPN or gateway. This feature is especially useful when sharing resources, such as virtual machines or databases, between VNets while maintaining network isolation.

VNet Peering in Azure (Source)

Azure ExpressRoute and VPN Gateway

Azure ExpressRoute and VPN Gateways provide reliable solutions for organizations that need secure, high-performance connectivity between on-premises networks and Azure cloud.

• ExpressRoute: ExpressRoute creates a private connection between your on-premises infrastructure and Azure, bypassing the public internet. This reduces latency while increasing reliability, making it ideal for mission-critical workloads. ExpressRoute enables you to extend your on-premises network into Azure while maintaining high bandwidth and consistent performance.
• VPN Gateway: Although not as efficient as ExpressRoute, a VPN Gateway is a low-cost solution for hybrid connectivity. It creates encrypted tunnels for data transfer between Azure VNets and on-premises environments. To optimize VPN performance:
  • Choose the correct VPN Gateway SKU based on your bandwidth and connection needs.
  • Use route-based VPNs for dynamic routing and greater scalability.

Accelerated Networking

Accelerated Networking offloads network traffic processing to dedicated hardware to boost Azure Virtual Machine performance. Its low latency, high throughput, and low CPU usage make it ideal for performance-sensitive applications.

Steps to Enable and Optimize Accelerated Networking:

• Enable Accelerated Networking on supported VMs (e.g., D/DSv2, F/Fsv2 series) during the VM creation process or later using the Azure CLI or Portal.
• Monitor Performance: Use Azure Monitor to track key metrics like latency and throughput, ensuring that Accelerated Networking delivers the expected improvements.
• Consider VM Size: Ensure you choose the right VM size to take full advantage of Accelerated Networking, as not all VM sizes support this feature.

Load Balancing for Performance Optimization

Azure includes several load balancing options to efficiently distribute network traffic across multiple services, improving performance and availability.

• Azure Load Balancer: Evenly distributes incoming traffic across multiple VMs in a VNet to balance transport layer (Layer 4) traffic and increase availability.
• Azure Application Gateway: Application Gateway, a Layer 7 load balancer, is ideal for web applications that need advanced HTTP request routing.

Also read: AWS vs Azure vs GCP: Which Cloud Platform Should You Learn?

Optimizing Network Latency and Bandwidth

In addition to using VNet Peering and ExpressRoute, you can apply the following strategies to optimize network performance in Azure:

• Proximity Placement Groups: Use proximity placement groups to ensure that your VMs are deployed physically close to each other within an Azure region, reducing intra-application latency.
• Traffic Manager: For globally distributed applications, use Azure Traffic Manager to route user traffic to the nearest data center based on network performance, geographic location, or weighted traffic distribution.

Monitoring Network Performance

Optimizing network performance requires monitoring. Azure Monitor and Network Watcher analyze traffic flow, performance metrics, and issues. For monitoring network performance in Azure, you can use:

• Azure Monitor: Azure Monitor analyzes network latency, bandwidth, and throughput to identify performance bottlenecks.
• Network Watcher: Use packet capture, connection troubleshooting, and NSG flow logs to diagnose and resolve network performance problems.

Advanced Azure Networking Configurations

User-defined routes allow you to control how traffic is routed within an Azure Virtual Network. As Azure automatically provides system routes to manage traffic between subnets, user-defined routes enable you to customize routing to your network’s specific requirements. This is particularly useful for scenarios involving traffic routing through firewalls or network appliances.

Azure Firewall and Application Gateway

Both Azure Firewall and Azure Application Gateway are used to secure and manage traffic within your network, but each has a different purpose.

• Azure Firewall: A fully managed, scalable firewall that enables you to centrally control network security policies across VNets. It assists with logging, threat detection, and rule enforcement for both inbound and outbound traffic.
• Azure Application Gateway: Designed primarily for web applications, it is a Layer 7 load balancer that provides application-level routing, SSL termination, and protection via the Web Application Firewall.

Azure Firewall manages and secures network traffic across multiple VNets, especially in centralized control and detailed logging scenarios. However, Application Gateway is better for web applications that need advanced routing, SSL offloading, and web vulnerability protection through the Web Application Firewall.

Securing Virtual Networks

Azure offers several VNet security tools including NSGs and firewalls. Azure DDoS Protection automatically detects and mitigates real-time DDoS attacks on public resources like web apps. Just-In-Time (JIT) Access allows administrators open management ports like SSH and RDP only when needed and for a limited time, reducing the risk of unauthorized access.

Azure Private Link allows secure connections to Azure Storage and SQL Database via a private IP in your VNet, bypassing the public internet.

Monitoring and Troubleshooting Azure Network Configurations

Your Azure network needs proper monitoring to run smoothly and securely. Regular monitoring helps you optimize network performance, detect issues before they affect applications, and comply with security policies. Understanding Azure’s monitoring tools is essential for managing and troubleshooting network configurations on the AZ-104 exam.

Azure Monitor

Azure Monitor provides comprehensive insights into Azure resource health and performance, including network configurations. Track metrics, set alerts, and analyze logs to monitor your network.

Key Features for Network Monitoring

The following are some key features for monitoring your network with Azure Monitor:

• Metrics and Logs: Azure Monitor monitors latency, bandwidth, and packet loss from VNets, NSGs, and VPN Gateways.
• Alerts: You can set up alerts for specific network performance metrics. For example, you can configure an alert for high latency or packet loss to detect issues early and take corrective action.
• Log Analytics: Analyze network logs with Azure Log Analytics. This can identify traffic flow patterns and anomalies to optimize network performance or troubleshoot issues.

Azure Network Watcher

Azure Network Watcher monitors and diagnoses Azure networks. It provides real-time insights and helps troubleshoot resource connectivity issues.

Key Tools in Network Watcher

The following are some key tools used in Network Watcher:

• Connection Monitor: Connection Monitor checks Azure resources like VMs and external endpoints for connectivity. It monitors network latency and connection status to help diagnose and fix issues.
• Packet Capture: With packet capture, you can capture and analyze VM network traffic in real-time. This helps troubleshoot application performance and security breaches.
• NSG Flow Logs: NSG flow logs provide details about traffic flowing through your Network Security Groups. You can use this data to audit traffic patterns and troubleshoot why certain traffic is being allowed or denied based on your NSG rules.
• IP Flow Verify: This tool checks NSG rules and routing tables to determine if a packet is allowed or denied, helping you troubleshoot connectivity issues caused by incorrect security or routing configurations.

Diagnosing Connectivity Issues

Azure provides tools to diagnose and fix network connectivity issues, which are crucial for network management and the AZ-104 exam. VPN Gateway troubleshooting with Azure Monitor and Network Watcher can help you monitor and resolve connectivity issues between on-premises networks and Azure.

You can use IP Flow Verify in Network Watcher to simulate traffic flows and check for NSG rules or routing configurations blocking or misdirecting traffic. The Connectivity Check feature in Network Watcher tests network communication between two resources, such as virtual machines or VMs and storage accounts, to ensure it works properly.

Conclusion

Cloud administrators interested in taking the AZ-104 Microsoft Azure Administrator exam must understand Azure Virtual Network configurations. In this article, we discussed VNets, subnets, and Network Security Groups or NSGs to control traffic, improve security, and segment workloads, which are important for managing the Azure environment and AZ-104 exam. We also explored advanced performance optimization techniques through VNet Peering, ExpressRoute, VPN Gateways, Accelerated Networking, and security tools like Azure Firewall and Application Gateway for managing traffic and safeguarding resources.

To excel in the AZ-104 exam, perform hands-on practice with these networking tools and gain confidence in using Azure Monitor and Network Watcher to troubleshoot and optimize configurations. To gain real-world experience, try these tools and consult Microsoft’s resources. Optimizing Azure Virtual Network configurations—refining subnet designs, tuning performance, or securing your network—will prepare you for the exam and managing professional Azure environments.