Auto-Connecting OpenVPN on Boot in a Windows AD Environment

1. The Challenge: Persistent VPN for Domain-Joined Machines

In a corporate environment that leverages Microsoft Active Directory (AD), it is critical for domain-joined computers to maintain a persistent connection to a domain controller. This ensures that group policies are applied, authentication requests are processed, and security postures are maintained.

This requirement becomes a challenge when users work remotely. A standard user-initiated VPN connection is insufficient, as the VPN tunnel must be established before the user logs in to Windows. Without this pre-login connection, the machine cannot communicate with the domain controller, leading to authentication issues and policy failures.

2. The Solution: OpenVPN Connect as a Windows Service

The solution is to configure the OpenVPN client to run as a system service that starts automatically on boot, independent of any user session. The OpenVPN Connect client for Windows includes a command-line utility specifically for this purpose: ovpnconnector.exe.

This utility allows a system administrator to install and manage a system-wide VPN connection that initializes as part of the Windows startup sequence.

3. Implementation Steps

The process is straightforward and can be easily scripted for automated deployment.

Step 1: Prepare the OpenVPN Profile

First, prepare the client .ovpn configuration file. This file contains all the necessary directives, certificates, and keys for the connection. For the service to recognize it, the file must be named ovpnconnector.ovpn.

Step 2: Stage the Profile

Place the ovpnconnector.ovpn file in the installation directory of OpenVPN Connect. By default, this is typically: C:\Program Files\OpenVPN Connect\

Step 3: Install and Start the Service

Using an elevated Command Prompt or PowerShell, navigate to the OpenVPN Connect installation directory and execute the following commands:

# Navigate to the installation directory
cd "C:\Program Files\OpenVPN Connect"

# Install the service. This registers the ovpnconnector.ovpn profile.
.\ovpnconnector.exe install

# Start the service immediately.
.\ovpnconnector.exe start

Once installed, the "OpenVPN Connect Service" will be visible in the Windows Services console (services.msc) and will be configured to start automatically with the system.

4. Conclusion

By using the ovpnconnector.exe utility, system administrators can ensure that remote, domain-joined Windows machines maintain a persistent and secure connection to the corporate network. This pre-login VPN tunnel is essential for the proper functioning of Active Directory services in a remote work environment.

This method provides a reliable solution for policy enforcement and authentication, demonstrating a key technique for managing Windows clients in a distributed network architecture.