Building a Production-Grade VPC on AWS: Secure Traffic Flow Explained

Hello, people! I’m back with a new blog. Have you ever wondered how traffic flows through different components before it reaches an application—and how it stays safe along the way? When we request information from an app, that request travels through many components before returning the response. It needs to remain secure, accurate, and protected from hacking. This is where a Virtual Private Cloud (VPC) comes into play.

A VPC is essentially a private cloud within a public cloud, adding an extra layer of security. In this blog, we’ll deep dive into how different VPC components help ensure safe and efficient traffic flow in production-grade systems.

Overview

In this project, we’ll implement a production-level environment where applications aren’t directly accessible from the internet, which provides primary safety. We’ll also use:

Load Balancers – to distribute traffic evenly across instances
Auto Scaling Groups – to automatically scale the number of instances
Jump Servers – to securely SSH into private instances
NAT Gateways – to allow private instances to access the internet safely
Internet Gateway (IGW) – connect the VPC to the public internet

Step 1: Create a VPC

Begin by creating a VPC and defining its IP range using a CIDR block. This determines the size of your VPC and the number of resources it can accommodate.

Step 2: Create Public and Private Subnets

Create public and private subnets across multiple Availability Zones (AZs) for fault tolerance and high availability.
Set up NAT Gateways in each AZ. These allow private instances to access the internet securely via an Elastic IP.
Attach an Internet Gateway (IGW) to your VPC. Public subnets use this IGW to send and receive traffic from the internet.

Routing configuration:

Public subnet route table → routes 0.0.0.0/0 to IGW
Private subnet route table → routes 0.0.0.0/0 to NAT Gateway

This ensures private instances can access the internet without being exposed directly.

Step 3: Set Up an Auto Scaling Group (ASG)

Create an Auto Scaling Group for your private subnets.
This group spans multiple AZs and automatically launches or terminates instances based on traffic.
Private instances do not have public IPs, enhancing security.

Step 4: Configure a Jump Server

Create a Jump Server with a public IP to act as a secure gateway.
Instead of exposing private instances directly, you access them via the jump server using SSH.

Step 5: Add a Load Balancer

Create a regional load balancer. It launches nodes in each AZ and attaches them to a target group containing private instances.

Traffic Flow:

Client requests first reach the Internet Gateway (IGW).
Requests are forwarded to the load balancer, which distributes traffic to private instances.
Responses travel back through the load balancer and IGW before reaching the client.

This setup ensures that private instances remain isolated while still handling external traffic efficiently.

Ready for Production

With this setup, you now have a production-grade VPC where:

Private instances are isolated from direct internet access
Traffic flows securely through load balancers, NAT gateways, and the IGW
The environment is scalable, fault-tolerant, and secure

This architecture demonstrates how modern cloud environments protect applications while maintaining reliable traffic flow.

Building a Production-Grade VPC: Secure Traffic Flow in the Cloud