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Notes relative to understanding VPNs and Configuration

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The following text was provided by Google Gemini 2.0. The pictures were drawn by Gary Zeien. The output was reviewed.

Please provide an explanation of this picture that includes details on the key objects in the picture, the relationships, and a summary of the key points being covered in this picture.

This diagram depicts a comparison and interconnection between Google Cloud Platform (GCP) and Amazon Web Services (AWS) networking components, specifically focusing on how to establish connectivity between Virtual Private Clouds (VPCs) in each cloud. It shows the equivalent services and the steps required to create a secure and functional connection.

Key Objects (GCP Side):

  • VPC Network (GCP): A virtual private cloud network in GCP, providing isolated network resources.
  • Subnet (GCP): A range of IP addresses within a VPC network.
  • Cloud Router (GCP): A service that provides dynamic routing between VPC networks and external networks, including other cloud providers.
  • Cloud VPN Gateway (GCP): A service that creates a VPN gateway for secure connections to other networks.
  • VPN Tunnel (GCP): A secure tunnel established between a Cloud VPN gateway and a peer VPN gateway (in AWS in this case).
  • External IP Address (GCP): A public IP address associated with the Cloud VPN gateway.
  • Firewall Rules (GCP): Rules that control network traffic in and out of VPC networks.

Key Objects (AWS Side):

  • VPC (AWS): A virtual private cloud in AWS, providing isolated network resources.
  • Subnet (AWS): A range of IP addresses within a VPC.
  • Virtual Private Gateway (VGW) (AWS): A service that creates a VPN gateway for secure connections to other networks.
  • Customer Gateway (CGW) (AWS): Represents the customer's side of the VPN connection (in this case, the GCP VPN gateway).
  • VPN Connection (AWS): The secure tunnel established between the VGW and the CGW.
  • Elastic IP Address (AWS): A static public IP address associated with the VGW.
  • Security Groups (AWS): Act as virtual firewalls for instances within a VPC.
  • Route Tables (AWS): Control how network traffic is routed within the VPC.

Relationships and Flow:

  1. VPCs and Subnets: Both GCP and AWS have VPCs as the foundational networking component. Subnets are used to divide VPCs into smaller, more manageable networks.
  2. VPN Gateways: Both clouds offer VPN gateway services (Cloud VPN Gateway in GCP and Virtual Private Gateway in AWS) to establish secure connections.
  3. Customer Gateway (AWS): In AWS, a Customer Gateway object represents the external VPN endpoint (the GCP VPN gateway). This is a crucial difference in terminology and setup.
  4. VPN Tunnels/Connections: The VPN tunnel (GCP) and VPN Connection (AWS) represent the secure, encrypted link between the two networks.
  5. External/Elastic IPs: Both sides require a public IP address for the VPN gateways to communicate. GCP uses External IP Addresses, while AWS uses Elastic IP Addresses.
  6. Routing:
    • Cloud Router (GCP): Dynamically exchanges routing information with the AWS VGW using BGP (Border Gateway Protocol). This automates route propagation.
    • Route Tables (AWS): Route tables are configured in AWS to direct traffic destined for the GCP VPC to the VPN connection.
  7. Firewall/Security Groups: Firewall rules in GCP and Security Groups in AWS control network traffic flow, ensuring only authorized traffic can pass through the VPN connection.

Key Steps for Establishing Connectivity (Simplified):

  • GCP:
    1. Create a VPC network and subnets.
    2. Create a Cloud VPN gateway and assign an external IP address.
    3. Create a Cloud Router and configure a BGP session with the AWS VGW.
    4. Create a VPN tunnel, specifying the AWS CGW information (public IP).
    5. Configure firewall rules to allow desired traffic.
  • AWS:
    1. Create a VPC and subnets.
    2. Create a Virtual Private Gateway.
    3. Create a Customer Gateway, specifying the GCP VPN gateway's public IP address.
    4. Create a VPN Connection between the VGW and CGW.
    5. Configure route tables to route traffic to the VPN connection.
    6. Configure security groups to allow desired traffic.

Key Points:

  • The diagram highlights the similarities and differences between GCP and AWS networking services.
  • It demonstrates the steps involved in establishing a secure site-to-site VPN connection between two cloud providers.
  • It emphasizes the importance of routing (Cloud Router/Route Tables) for proper traffic flow.
  • It shows the need for firewall/security group configuration to control traffic.
  • The use of BGP via Cloud Router in GCP simplifies the routing configuration on the GCP side, as routes are dynamically learned from AWS.

In summary, this diagram provides a visual guide for establishing interconnection between GCP and AWS VPCs, focusing on VPN connections and the necessary configuration steps in each cloud environment. It's a useful resource for network architects and engineers working in hybrid cloud environments.

Based on this tutorial

Last update: January 15, 2025
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