AWS Client VPN, frequent disconnect troubleshooting.

Hello.

Please check the AWS Client VPN connection log.
https://docs.aws.amazon.com/vpn/latest/clientvpn-admin/cvpn-working-with-connection-logs.html

You should also check the logs of the Client VPN software installed on your PC.
If it's provided by AWS, the logs should be output to the following folder.
https://docs.aws.amazon.com/vpn/latest/clientvpn-user/windows-troubleshooting.html

C:\Users\User\AppData\Roaming\AWSVPNClient\logs

To troubleshoot your intermittent AWS Client VPN disconnects on Windows 11 (24H2) systems with version 5.2.1, here's guidance on which logs to review and what to look for:

Log Files to Review:

1. AWS Client VPN application logs - These contain information about connection attempts and errors
2. OpenVPN logs - These provide detailed technical information about the VPN connection
3. Windows service logs - These may contain relevant system-level information

What to Look for in the Logs:

1. Error messages related to authentication failures
2. Network connectivity issues or packet loss indicators
3. TLS handshake failures
4. Messages about "Re-establishing connection"
5. Firewall blocking notifications for ports 443 or 1194 (commonly used for VPN)
6. DNS resolution problems
7. Messages about the TAP-Windows adapter
8. Any indication of IP address space changes (which can trigger disconnections)
9. Security association issues

Common causes for intermittent disconnects include:

• Network congestion in your local environment
• Firewall interference blocking required ports
• Power management settings on your Windows 11 devices
• DNS resolution problems
• Routing issues specific to your location
• Expired client certificates or Certificate Revocation List (CRL)
• Multiple security associations causing previous connections to drop

You can also send diagnostic logs directly to AWS Support:

1. Open the AWS VPN Client app
2. Choose Help, then Send Diagnostic Logs
3. Follow the prompts to send the logs and obtain a reference number
4. Contact AWS Support with this reference number for more detailed assistance
   Sources
   Troubleshooting Intermittent Connection Loss Between AWS VPN Client and EC2 Instance in a VPC | AWS re:Post
   Troubleshooting AWS Client VPN: Tunnel connectivity issues to a VPC - AWS Client VPN
   Troubleshooting AWS Client VPN connections with Windows-based clients - AWS Client VPN
   AWS Client VPN shows "Re-establishing connection" message intermitently | AWS re:Post