Azure Networking Basics

Overview

Azure networking provides the foundation for how resources communicate securely and efficiently. This tutorial covers Virtual Networks, Subnets, Network Security Groups, Load Balancers, and DNS.

Virtual Networks (VNet)

A VNet is a logical isolation of the Azure cloud dedicated to your subscription. It enables you to segment your resources and control traffic.

Below is a sample ARM template to create a VNet with two subnets.

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "resources": [
    {
      "type": "Microsoft.Network/virtualNetworks",
      "apiVersion": "2021-05-01",
      "name": "myVNet",
      "location": "[resourceGroup().location]",
      "properties": {
        "addressSpace": { "addressPrefixes": ["10.0.0.0/16"] },
        "subnets": [
          { "name": "subnetApp", "properties": { "addressPrefix": "10.0.1.0/24" } },
          { "name": "subnetDB",  "properties": { "addressPrefix": "10.0.2.0/24" } }
        ]
      }
    }
  ]
}

Network Security Groups (NSG)

NSGs let you control inbound and outbound traffic to resources at subnet or NIC level.

• Allow/deny rules based on protocol, port, and IP.
• Prioritize rules using a numeric order.

Load Balancers

Azure Load Balancer distributes incoming traffic across multiple VMs for high availability.

Azure DNS

Azure DNS provides ultra‑reliable, low‑latency DNS resolution for your domain names.

Use Azure CLI to create a DNS zone:

az network dns zone create -g MyResourceGroup -n contoso.com

Best Practices

1. Separate workloads using distinct subnets.
2. Apply NSG rules least‑privilege principle.
3. Use Azure Monitor for network diagnostics.
4. Implement Azure Firewall for centralized security.