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AWS Community Builders profile image Elizabeth Adeotun Adegbaju
Elizabeth Adeotun Adegbaju for AWS Community Builders

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AWS Cloud Path Week 17: How to Configure AWS Client VPN

#aws #networking #security #tutorial

Welcome to another technical tutorial in the AWS Cloud Path series! In this guide, we'll walk through the process of setting up AWS Client VPN, a fully managed remote access VPN solution that enables secure access to your AWS resources from anywhere.

Missed the session? Catch up here:

Prerequisites

  • An AWS account with necessary permissions
  • Basic understanding of VPC and networking concepts

Understanding AWS Client VPN

Before diving into the setup, let's understand what AWS Client VPN is and how it differs from Site-to-Site VPN:

  • AWS Client VPN is designed for individual remote access from anywhere
  • Unlike Site-to-Site VPN, it doesn't require a customer gateway or fixed location
  • It's ideal for remote workers who need secure access to AWS resources
  • Supports both mutual authentication and user-based authentication methods
  • Fully elastic and automatically scales based on demand

Architecture Overview

The setup we'll be creating includes:

  • A VPC with CIDR block 10.0.0.0/16
  • 4 private subnets:
    • 2 subnets for RDS databases
    • 2 subnets for Client VPN endpoints
  • Client VPN endpoint with associated Elastic Network Interfaces
  • Certificate management through AWS Certificate Manager (ACM)

Step-by-Step Configuration

1. Generate and Import Certificates

First, we need to create and import the necessary certificates:

a. Clone the OpenVPN easy-rsa repository:

git clone https://github.com/OpenVPN/easy-rsa.git
cd easy-rsa/easyrsa3
./easyrsa init-pki
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b. Generate the server certificate:

./easyrsa build-ca nopass
./easyrsa build-server-full server nopass
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c. Import certificates to AWS Certificate Manager (ACM):

  • Navigate to ACM in the AWS Console
  • Click "Import Certificate"
  • Import the certificate body, private key, and certificate chain

2. Create the VPC Infrastructure

Set up your VPC with the following configuration:

  • CIDR block: 10.0.0.0/16
  • 4 private subnets across 2 availability zones: 
  - RDS subnet 1: 10.0.2.0/24
  - RDS subnet 2: 10.0.4.0/24
  - Client VPN subnet 1: 10.0.6.0/24
  - Client VPN subnet 2: 10.0.8.0/24
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3. Create Client VPN Endpoint

a. Navigate to VPC → Client VPN Endpoints
b. Click "Create Client VPN Endpoint"
c. Configure the following settings:

- Name tag: AWS-Client-VPN
- Client IPv4 CIDR: Choose an unused CIDR block
- Server certificate: Select the certificate imported to ACM
- Authentication: Choose Mutual Authentication
- Client certificate: Select the client certificate
- Enable split-tunnel routing
- Select your VPC and subnets
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4. Configure Security and Routing

a. Associate target networks:

  • Select the Client VPN subnets
  • Wait for association to complete

b. Add authorization rules:

  • Configure network access
  • Set up routing tables for VPC access

5. Download and Configure Client

a. Download the Client VPN configuration file from the AWS Console
b. Install AWS Client VPN desktop application
c. Import the configuration file
d. Connect using the client certificate

Best Practices and Considerations

Security

  • Always use strong authentication methods
  • Regularly rotate certificates
  • Implement least privilege access

Cost Management

  • Enable split-tunnel to reduce data transfer costs
  • Monitor connection usage
  • Consider connection timeout settings

Performance

  • Associate endpoints with multiple subnets for high availability
  • Configure DNS servers appropriately
  • Monitor connection quality

Troubleshooting Tips

Connection Issues:

  • Verify certificate validity
  • Check subnet associations
  • Confirm security group rules

Access Problems:

  • Verify authorization rules
  • Check routing tables
  • Validate client configuration

Conclusion

AWS Client VPN provides a secure and scalable solution for remote access to your AWS resources. By following this guide, you've learned how to:

  • Set up certificates for authentication
  • Create and configure a Client VPN endpoint
  • Associate networks and configure routing
  • Set up client access

The setup we've covered provides a foundation for secure remote access to your AWS resources. You can further customize the configuration based on your specific security and access requirements.

Next Steps

  • Implement user-based authentication with AWS IAM
  • Set up connection logging and monitoring
  • Configure additional security features like multi-factor authentication
  • Integrate with your existing identity provider

Remember to review the AWS Client VPN documentation for detailed information about advanced features and configurations.

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