Understanding Azure Virtual Network Basics
An Azure virtual network (VNet) is the fundamental building block for your private network in Azure. It represents your own network in Azure, with the ability to contain private IP address space, subnets, and route tables.
What is an Azure Virtual Network?
A VNet enables many types of Azure resources, such as Azure virtual machines (VMs), to securely communicate with each other, with the internet, and with your on-premises networks. A VNet is:
- A logical isolation of the Azure cloud dedicated to your subscription.
- A representation of your own network in Azure.
- Configurable with your own IP address space, subnets, route tables, and network security groups.
Key Components of a Virtual Network:
IP Addressing
When you create a VNet, you define a private IP address space for it using CIDR notation. This address space can be divided into multiple subnets. Azure resources within the same VNet can communicate with each other directly by default. You can also connect multiple VNets together and connect a VNet to your on-premises network.
Subnets
A subnet is a range of IP addresses within your VNet. After you create a VNet, you can divide it into one or more subnets. Each subnet can contain Azure resources. When you create a subnet, you specify a CIDR notation range for that subnet, which must be within the VNet's address space.
Route Tables
Route tables contain rules, called routes, that tell your network traffic how to move between subnets, your VNet, the internet, and your on-premises networks. By default, Azure creates a system route table for each VNet. You can also create custom route tables and associate them with subnets to control traffic flow.
Network Security Groups (NSGs)
An NSG is a stateless packet filtering firewall that you can associate with one or more NICs or subnets. NSGs contain security rules that allow or deny network traffic to resources connected to Azure. NSGs can be configured to allow or deny traffic based on source and destination IP address, port, and protocol.
Benefits of Azure Virtual Networks:
- Security: Isolate your resources and control network traffic with NSGs and firewalls.
- Connectivity: Seamlessly connect your Azure resources to each other, to the internet, and to your on-premises networks using VPN Gateway or ExpressRoute.
- Scalability: VNets can scale to accommodate your growing Azure deployment.
- Flexibility: Define your network topology, IP addressing scheme, and routing rules to meet your specific needs.
Common Use Cases:
- Hosting application tiers (e.g., web, application, and data tiers) in separate subnets for security and management.
- Connecting Azure resources to your on-premises datacenter for a hybrid cloud solution.
- Creating secure, isolated environments for development, testing, and production workloads.
- Implementing network segmentation for compliance and security best practices.
Azure Virtual Network is a cornerstone service for building secure and scalable cloud solutions on Azure. Understanding its basic components and benefits is crucial for any Azure deployment.