Azure VPC/Vnet Setup Guide for Public and Private Subnets

This document provides a step-by-step guide for replicating an AWS VPC infrastructure in Azure, with an equivalent setup for subnets, route tables, Internet Gateway, NAT Gateway, and Network Security Groups (NSGs).

1. Create a Virtual Network (VNet)

In AWS, a VPC is equivalent to a VNet in Azure. This is the first step to replicate your AWS infrastructure.

Steps:

Create a new Virtual Network:
- Resource Group: Create or select an existing resource group.
- Name: prod-vnet
- Region: Central India (or another region closest to Mumbai)
- Address space: Use the same CIDR range as your VPC, e.g., 10.0.0.0/16.
Add Subnets:
- Public subnets:
  - Subnet-1 (prod-public-subnet-1): 10.0.0.0/20
  - Subnet-2 (prod-public-subnet-2): 10.0.16.0/20
  - Subnet-3 (prod-public-subnet-3): 10.0.32.0/20
- Private subnets:
  - Subnet-1 (prod-private-subnet-1): 10.0.48.0/20
  - Subnet-2 (prod-private-subnet-2): 10.0.64.0/20
  - Subnet-3 (prod-private-subnet-3): 10.0.80.0/20
Click Create.

2. Create and Assign Route Tables

Steps:

Create two Route Tables:
- prod-public-route-table
- prod-private-route-table
For prod-public-route-table:
- Route: 0.0.0.0/0 → Internet Gateway
For prod-private-route-table:
- Route: 0.0.0.0/0 → Virtual Network Gateway (for NAT Gateway)
Associate Route Tables with Subnets:
- Public subnets: Associate with prod-public-route-table
- Private subnets: Associate with prod-private-route-table

3. Set Up Internet Gateway (Public IP)

Azure uses a Public IP Address and Load Balancer for public-facing resources.

Steps:

Create a Public IP Address for the Internet Gateway.
Assign the public IP to a Load Balancer or VM for internet-facing resources.

4. Set Up NAT Gateway

Steps:

Go to NAT Gateway in Azure.
Create a NAT Gateway:
- Assign a public IP.
- Associate the NAT Gateway with the private subnets.

5. Set Up Network Security Groups (NSGs)

Steps:

Create NSGs:
- Public NSG: Allow inbound internet traffic.
- Private NSG: Allow traffic only from within the VNet or specific subnets.
Assign NSGs to respective subnets:
- Public subnets: Assign the Public NSG.
- Private subnets: Assign the Private NSG.

6. Deploy Resources

Validate your network setup by deploying VMs in the following manner:
- VM in Public Subnet: Test internet connectivity.
- VM in Private Subnet: Verify traffic flow through the NAT Gateway.

7. Monitoring and Automation

Use Azure Monitor for logging and monitoring traffic.
Add alerts for traffic anomalies or misconfigurations.
For repeated setups, use Azure CLI, PowerShell, or Terraform for automation.

Architecture Diagram

               +------------------------------------+
               |             Azure VNet            |
               +------------------------------------+
               |  Address Space: 10.0.0.0/16        |
               +------------------------------------+
                 /         |          |          \
                /          |          |           \
        +------------+ +------------+ +------------+ +------------+
        | Public Subnet| | Public Subnet| | Public Subnet| | Private Subnet|
        | 10.0.0.0/20  | | 10.0.16.0/20| | 10.0.32.0/20| | 10.0.48.0/20  |
        +------------+ +------------+ +------------+ +------------+
                 |          |            |           | 
         +-----------------------------------------------+
         |                 NAT Gateway                  |
         +-----------------------------------------------+
                 |          |            |           |
        +-----------------+ +------------------+ +-----------------+
        | Private Subnet  | | Private Subnet    | | Private Subnet  |
        | 10.0.64.0/20    | | 10.0.80.0/20      | | 10.0.96.0/20    |
        +-----------------+ +------------------+ +-----------------+

This diagram represents your VNet, subnets (both public and private), and NAT Gateway setup in Azure.

Azure Monitor Grafana Public Azure Blob