VPC, Subnets & Routing

In this step, we establish the isolated network environment for IELTS BandUp. We will create a Virtual Private Cloud (VPC), partition it into subnets across multiple Availability Zones, and configure routing for internet access.

1. Create the VPC

First, we need a private network space.

  1. Navigate to the VPC Dashboard.
  2. Click Create VPC.
  3. Choose VPC only.
  4. Name tag: band-up-vpc
  5. IPv4 CIDR block: 10.0.0.0/16 (This provides 65,536 IP addresses, sufficient for future scaling).
  6. Leave other settings as default and click Create VPC.

VPC Settings VPC Created Successfully

2. Create Subnets

Next, we divide the VPC into smaller networks (Subnets) distributed across two Availability Zones (AZs) for High Availability. We will follow this IP schema:

Subnet NameTypeCIDR BlockAvailability Zone
public-subnet-1Public10.0.0.0/24ap-southeast-1a
public-subnet-2Public10.0.1.0/24ap-southeast-1b
private-app-subnet-1Private10.0.2.0/24ap-southeast-1a
private-app-subnet-2Private10.0.3.0/24ap-southeast-1b
private-database-subnet-1Database10.0.4.0/24ap-southeast-1a
private-database-subnet-2Database10.0.5.0/24ap-southeast-1b

Steps:

  1. Go to Subnets > Create subnet.
  2. Select the VPC ID: band-up-vpc.
  3. Enter the Subnet name, Availability Zone, and IPv4 CIDR block for each subnet according to the table above.
  4. Repeat the process until all 6 subnets are created.

Create Public Subnet Create Database Subnet

3. Create Internet Gateway (IGW)

By default, a VPC is closed to the internet. To allow resources in our Public Subnets to communicate with the outside world, we need an Internet Gateway.

  1. Go to Internet gateways > Create internet gateway.
  2. Name tag: band-up-igw.
  3. Click Create internet gateway.
  4. After creation, click Actions > Attach to VPC.
  5. Select band-up-vpc and click Attach internet gateway.

Attach IGW

4. Configure Route Tables

Finally, we need to direct traffic from our Public Subnets to the Internet Gateway.

  1. Go to Route tables > Create route table.
  2. Name: public-route-table.
  3. VPC: band-up-vpc.
  4. Click Create route table.

Add Route to Internet:

  1. Select the newly created public-route-table.
  2. Go to the Routes tab > Edit routes.
  3. Add a new route:
    • Destination: 0.0.0.0/0 (All traffic).
    • Target: Select Internet Gateway -> band-up-igw.
  4. Click Save changes.

Edit Routes

Associate Subnets:

  1. Go to the Subnet associations tab > Edit subnet associations.
  2. Select only the Public Subnets (public-subnet-1 and public-subnet-2).
  3. Click Save associations.

Subnet Association

5. Verify Configuration

To verify that the network architecture is correctly established, navigate back to your VPC Dashboard, select band-up-vpc, and view the Resource map tab. You should see a clear structure linking your Public Subnets to the Route Table and the Internet Gateway.

VPC Resource Map Result