Introduction.
In today’s increasingly hybrid IT environments, securely connecting on-premises infrastructure with cloud platforms like AWS has become a top priority for businesses of all sizes. Whether you’re running mission-critical workloads, extending your private data center, or simply enabling cloud-based development and testing environments, a secure, reliable, and scalable connection between your local network and AWS is essential. This is where AWS Site-to-Site VPN (Virtual Private Network) comes in—a robust solution that creates an encrypted tunnel between your on-premises network and your Amazon Virtual Private Cloud (VPC), allowing seamless and secure data exchange over the internet.
AWS Site-to-Site VPN is designed to support high-availability architectures and is a cost-effective alternative to dedicated connections like AWS Direct Connect. It supports industry-standard IPsec VPN tunnels and can be configured for either static routing or dynamic routing via Border Gateway Protocol (BGP), giving you flexibility based on your existing network setup. The best part? You don’t need to be a cloud networking expert to get started. AWS provides an intuitive console interface and downloadable configuration templates for most popular hardware vendors, including Cisco, Juniper, Fortinet, and pfSense.
In this guide, we’ll walk you step-by-step through the process of setting up an AWS Site-to-Site VPN connection. From creating a Virtual Private Gateway, defining your Customer Gateway, and provisioning the VPN connection itself, to configuring your on-premises device and updating route tables—we’ll cover it all. You’ll learn how to build a secure bridge between your AWS VPC and your on-premises data center using best practices for encryption, routing, and fault tolerance. Whether you’re setting this up for the first time or refining your existing hybrid network strategy, this guide will help you get up and running quickly and confidently.
By the end of this post, you’ll have a fully functional AWS Site-to-Site VPN connection and a solid understanding of how it works. You’ll also gain insights into how to monitor the connection, ensure high availability, and scale your architecture as your needs evolve. So grab your coffee, open up the AWS Console, and let’s dive into securely extending your network into the AWS cloud.
Prerequisites
- An existing Virtual Private Cloud (VPC) in AWS
- A Customer Gateway (CGW) device on-premises (can be a hardware or software VPN device)
- The public IP address of your on-premises VPN device
Step 1: Create or Choose a VPC
If you don’t have one yet:
- Go to VPC Dashboard
- Click “Create VPC”
- Choose a CIDR block, e.g.,
10.0.0.0/16
Step 2: Create a Virtual Private Gateway (VGW)
- In the VPC Console, go to “Virtual Private Gateways”
- Click “Create virtual private gateway”
- Name:
MyVGW - ASN: Leave default or set a custom Autonomous System Number
- Name:
- After creation, attach it to your VPC:
- Select the VGW → Click “Actions” → Attach to VPC
Step 3: Create a Customer Gateway (CGW)
- Go to “Customer Gateways” in the VPC console
- Click “Create customer gateway”
- Name:
MyOnPremVPN - Routing: Choose Static or Dynamic (BGP)
- IP Address: Public IP of your on-prem VPN device
- ASN (if using BGP): Your on-premises ASN
- Name:
Step 4: Create a Site-to-Site VPN Connection
- Go to “VPN Connections”
- Click “Create VPN Connection”
- Name:
MyVPNConnection - Target Gateway: Choose Virtual Private Gateway
- Virtual Private Gateway: Select the one you created earlier
- Customer Gateway: Choose Existing and select the CGW you made
- Routing Options:
- Static: Enter on-premises CIDR ranges (e.g.,
192.168.1.0/24) - Dynamic: Uses BGP
- Static: Enter on-premises CIDR ranges (e.g.,
- Name:
Step 5: Download VPN Configuration
Once the VPN is created:
- Select your VPN → Click “Download Configuration”
- Choose your on-prem device/vendor (Cisco, Fortinet, pfSense, etc.)
- This file includes tunnel IPs, BGP config, shared secrets, etc.
Step 6: Configure On-Premises VPN Device
Use the settings from the downloaded config file to:
- Set up IPsec tunnels
- Use shared secrets for IKE authentication
- Match routing settings (BGP or static)
Step 7: Update VPC Route Tables
- Go to the Route Tables in your VPC
- Add a route to your on-prem CIDR (e.g.,
192.168.1.0/24) pointing to the Virtual Private Gateway
Step 8: Test the Connection
- You should now be able to ping from on-prem to AWS and vice versa
- Check VPN tunnel status in AWS → Should be “UP”
- Use CloudWatch or VPN metrics to monitor tunnel health
Conclusion.
Setting up a Site-to-Site VPN connection in AWS may seem complex at first, but once you understand the moving parts—Virtual Private Gateway, Customer Gateway, VPN tunnels, and routing—it becomes a powerful and manageable way to extend your on-premises network into the cloud. Whether you’re building a hybrid architecture, enabling secure data transfers, or preparing for disaster recovery, AWS Site-to-Site VPN gives you the flexibility, encryption, and scalability needed to support modern infrastructure needs.
By following the step-by-step process outlined in this guide, you’ve learned how to provision and configure each component, integrate it with your existing network, and ensure that traffic flows securely between your environments. With the tunnel now live and your route tables properly updated, you’re ready to take full advantage of AWS resources from within your own private network.
As your cloud journey continues, you can build on this foundation by exploring high availability with dual VPN connections, performance enhancements with AWS Direct Connect, and network segmentation using Transit Gateway. Stay curious, keep optimizing, and always prioritize security when expanding your infrastructure footprint.
If this guide helped you, feel free to share it with your team or drop a comment below. And if you’re ready to go even deeper—monitoring VPN health, automating deployments with Terraform, or integrating with multi-region VPCs—I’ve got more content on the way. Until then, happy building!
