Connecting AWS to GCP: A Comprehensive Guide to Site-to-Site VPN

With the rise of multi-cloud strategies, more and more organizations are operating in environments where they deploy resources across multiple cloud providers. This trend necessitates secure and efficient communication between resources located in different cloud platforms. In this post, we'll walk you through setting up a Site-to-Site VPN connection between Amazon Web Services (AWS) and Google Cloud Platform (GCP), allowing resources in both clouds to communicate with each other securely over the internet.

What is a Site-to-Site VPN?

A Site-to-Site Virtual Private Network (VPN) is a connection that helps in bridging two networks in different locations over the internet in a secure manner. Traffic is encrypted on one end and decrypted on the other, ensuring data confidentiality and integrity between the two sites.

Prerequisites:

• Active AWS and GCP accounts
• Basic understanding of VPC in AWS and GCP

Steps to Establish a Site-to-Site VPN between AWS and GCP:

1. AWS Setup:

• Virtual Private Gateway (VPG):

  • Navigate to the VPC Dashboard.
  • Create a Virtual Private Gateway and attach it to the desired VPC.

• Customer Gateway (CGW):

  • For the IP, you'll need the external IP address of the GCP VPN.
  • Create a new Customer Gateway with the GCP VPN's IP.

• Site-to-Site VPN Connection:

  • Create a new VPN connection. Choose the previously created VPG and CGW.
  • Note the Tunnel details, especially the shared keys and IP addresses.

2. GCP Setup:

• Cloud Router and VPN:

  • Go to the 'Hybrid Connectivity' section in GCP.
  • Create a Cloud Router.
  • Create a VPN, linking it to the previously created Cloud Router.
  • Under the 'Tunnels' section, use the AWS Tunnel details. Ensure that IKE version, shared secrets, and traffic selectors match with AWS settings.

• Firewall Rules:

  • Setup firewall rules in GCP to allow ingress and egress traffic from AWS VPC IP ranges.

3. Verify Connectivity:

• Once both tunnels (AWS has two tunnels for redundancy) show as UP, test connectivity.
  • From AWS, ping a GCP VM's internal IP and vice-versa.
  • Monitor VPN metrics and logs in both AWS and GCP for any anomalies.

Benefits:

1. Security: Data is encrypted end-to-end.
2. Flexibility: Resources in both AWS and GCP can communicate seamlessly.
3. Cost-Effective: Reduces the need for dedicated, physical connections.

Conclusion:

Connecting AWS to GCP using a Site-to-Site VPN establishes a secure, private connection between the two cloud platforms. This guide provides a basic understanding of setting up this connection, but real-world scenarios might require additional configurations like BGP, dynamic routes, and more, depending on the architecture and requirements.

Remember, while VPNs offer encryption and security, it's essential to continually monitor, patch, and update configurations to ensure optimal performance and security. Happy networking!