How to Host OpenVPN Server on Windows: A Step-by-Step Guide for Devs

Welcome, Dev, to this comprehensive guide on how to host an OpenVPN server on Windows. OpenVPN is a free and open-source virtual private network (VPN) software that allows you to create a secure and encrypted connection between two or more devices over the internet. In this article, we will walk you through the process of setting up an OpenVPN server on a Windows machine, including the installation, configuration, and troubleshooting steps. By the end of this guide, you will have a fully functional OpenVPN server that you can use to protect your online privacy, bypass internet censorship, and access geo-restricted content.

Table of Contents

1. Introduction
2. Prerequisites
3. Installation
4. Configuration
5. Generating Certificates and Keys
6. Starting the OpenVPN Service
7. Testing the Connection
8. Creating User Accounts
9. Setting up Client Devices
10. Advanced Configuration
11. Firewall Settings
12. Troubleshooting
13. FAQ

1. Introduction

OpenVPN is a popular VPN protocol that provides a high level of security and flexibility. It can be used to connect remote workers, branch offices, or mobile devices to a central network, or to create a secure tunnel between two devices. Unlike other VPN protocols, such as PPTP or L2TP, OpenVPN uses SSL/TLS encryption to protect the data in transit from eavesdropping and tampering. It also supports various authentication methods, including username/password, certificates, and two-factor authentication.

In this guide, we will show you how to install and configure OpenVPN server on a Windows machine. We will assume that you have basic knowledge of networking, Windows administration, and command-line interface. We will use the latest version of OpenVPN, which is compatible with Windows 10, 8, 7, and Server 2016, 2012, and 2008.

2. Prerequisites

Before you start, make sure you have the following:

• A Windows machine with a minimum of 1 GHz CPU, 1 GB RAM, and 10 GB free disk space
• A dedicated public IP address or a domain name pointing to the machine
• Access to the machine as an administrator

2.1. Choosing the Edition

OpenVPN is available in two editions: Community and Access Server. The Community edition is free and open-source, while the Access Server edition is a commercial product that offers additional features and support. In this guide, we will focus on the Community edition, which is suitable for small to medium-sized deployments.

2.2. Checking the Compatibility

Make sure that your Windows machine is compatible with OpenVPN by checking the hardware and software requirements on the OpenVPN website. You should also check the compatibility of any client devices that you plan to connect to the server.

3. Installation

The first step is to download and install the OpenVPN software on the Windows machine. You can download the latest version from the official website: https://openvpn.net/community-downloads/

3.1. Installing the Software

To install the software, follow these steps:

1. Download the OpenVPN installer for Windows.
2. Run the installer as an administrator.
3. Accept the license agreement.
4. Choose the components to install (we recommend installing all components).
5. Choose the installation directory.
6. Choose the Start Menu folder.
7. Choose the additional tasks (we recommend adding the OpenVPN to the system path).
8. Click Install.
9. Wait for the installation to complete.
10. Click Next.
11. Click Finish.

3.2. Checking the Installation

To check if the installation was successful, open a command prompt and type “openvpn –version”. You should see the version number of the OpenVPN software. If you see an error message, check the installation directory and the system path settings.

4. Configuration

The next step is to configure the OpenVPN server to listen on a specific port and protocol, and to use a specific network interface. You can do this by creating a configuration file, which is a text file that contains the settings for the server. The configuration file should be placed in the “config” folder of the OpenVPN directory, which is usually located in “C:\Program Files\OpenVPN”.

4.1. Creating the Configuration File

To create the configuration file, follow these steps:

1. Open a text editor (e.g., Notepad).
2. Type the following settings:

Save the file as “server.conf” in the “config” folder of the OpenVPN directory.

4.2. Editing the Firewall Settings

The Windows Firewall may block incoming traffic on the OpenVPN port. You need to create a firewall rule to allow incoming traffic on the specified port. To do this, follow these steps:

1. Open the Windows Firewall with Advanced Security.
2. Click Inbound Rules.
3. Click New Rule.
4. Choose Port.
5. Choose UDP and enter the port number (e.g., 1194).
6. Choose Allow the connection.
7. Choose the network location for the rule (e.g., Domain, Private, Public).
8. Enter a name for the rule (e.g., OpenVPN).
9. Click Finish.

5. Generating Certificates and Keys

To establish a secure connection between the OpenVPN server and the client devices, you need to generate a set of certificates and keys. The certificates and keys are used to authenticate the devices and encrypt the data in transit. You will need to generate a CA certificate, a server certificate, and a set of client certificates.

5.1. Creating the CA Certificate

The CA (Certificate Authority) certificate is a self-signed certificate that is used to sign the server and client certificates. To create the CA certificate, follow these steps:

1. Open a command prompt as an administrator.
2. Navigate to the OpenVPN directory (e.g., “cd C:\Program Files\OpenVPN”).
3. Type “easyrsa init-pki” to initialize the Public Key Infrastructure (PKI) directory.
4. Type “easyrsa build-ca” to build the CA certificate.
5. Enter a passphrase for the CA key (e.g., “password”).
6. Confirm the passphrase.
7. Enter the distinguished name (DN) for the CA certificate (e.g., “CN=OpenVPN-CA”).
8. Confirm the DN.

5.2. Creating the Server Certificate and Key

The server certificate and key are used to authenticate the OpenVPN server to the client devices. To create the server certificate and key, follow these steps:

1. Open a command prompt as an administrator.
2. Navigate to the OpenVPN directory (e.g., “cd C:\Program Files\OpenVPN”).
3. Type “easyrsa gen-req server nopass” to generate the server certificate request.
4. Enter the DN for the server certificate (e.g., “CN=OpenVPN-Server”).
5. Confirm the DN.
6. Type “easyrsa sign-req server server” to sign the server certificate request.
7. Type “yes” to confirm the signing.
8. Type “Enter” to use the default CA key passphrase.
9. Type “openssl dhparam -out dh2048.pem 2048” to generate the Diffie-Hellman parameters.

5.3. Creating the Client Certificates and Keys

The client certificates and keys are used to authenticate the client devices to the OpenVPN server. To create the client certificates and keys, follow these steps:

1. Open a command prompt as an administrator.
2. Navigate to the OpenVPN directory (e.g., “cd C:\Program Files\OpenVPN”).
3. Type “easyrsa gen-req client1 nopass” to generate the client certificate request.
4. Enter the DN for the client certificate (e.g., “CN=OpenVPN-Client1”).
5. Confirm the DN.
6. Type “easyrsa sign-req client client1” to sign the client certificate request.
7. Type “yes” to confirm the signing.
8. Type “Enter” to use the default CA key passphrase.
9. Type “copy /b client1.crt+client1.key client1.ovpn” to create a configuration file for the client device.

6. Starting the OpenVPN Service

The next step is to start the OpenVPN service on the Windows machine. The service will listen on the specified port and protocol, and use the specified configuration file. To start the service, follow these steps:

1. Open a command prompt as an administrator.
2. Type “net start openvpnservice” to start the OpenVPN service.

7. Testing the Connection

The final step is to test the connection between the OpenVPN server and the client devices. You can use the OpenVPN GUI client on a Windows device to connect to the server. To do this, follow these steps:

1. Download the OpenVPN GUI client for Windows from the official website: https://openvpn.net/community-downloads/
2. Install the client on the Windows device.
3. Copy the client configuration file (e.g., “client1.ovpn”) to the device.
4. Open the OpenVPN GUI client.
5. Right-click on the system tray icon and choose “Import file…”.
6. Choose the client configuration file and click Open.
7. Right-click on the system tray icon and choose “Connect”.
8. Enter the username and password for the client device.
9. Confirm the connection.
10. Check the log for any errors or warnings.
11. Test the connection by accessing a website or a network resource.

8. Creating User Accounts

By default, the OpenVPN server does not require any authentication for the client devices. This means that anyone who has the client configuration file can connect to the server. To add an extra layer of security, you can create user accounts and passwords for the client devices. To do this, follow these steps:

1. Open a command prompt as an administrator.
2. Navigate to the OpenVPN directory (e.g., “cd C:\Program Files\OpenVPN”).
3. Type “easyrsa gen-req username nopass” to generate the user certificate request.
4. Enter the DN for the user certificate (e.g., “CN=OpenVPN-User”).
5. Confirm the DN.
6. Type “easyrsa sign-req client username” to sign the user certificate request.
7. Type “yes” to confirm the signing.
8. Type “Enter” to use the default CA key passphrase.
9. Type “copy /b username.crt+username.key username.ovpn” to create a configuration file for the user device.
10. Edit the “server.conf” configuration file and add the following lines:

auth-user-pass-verify “C:\Program Files\OpenVPN\config\auth.exe” via-env
client-cert-not-required
username-as-common-name

Save the configuration file and restart the OpenVPN service.

9. Setting up Client Devices

Once you have created the client certificates and keys, you can set up the client devices to connect to the OpenVPN server. The settings may vary depending on the client device and the OpenVPN client software used. In general, you need to do the following:

• Install the OpenVPN client software on the client device.
• Copy the client configuration file (e.g., “client1.ovpn”) to the device.
• Import the configuration file to the client software.
• Enter the username and password, if required.
• Connect to the OpenVPN server.

10. Advanced Configuration

You can customize the OpenVPN server configuration by modifying the “server.conf” file. The file contains various settings that control the behavior of the server, such as the cipher, the compression, the DNS server, and the routing. You can also use environment variables to pass additional parameters to the server, such as the maximum number of clients, the log file location, and the verbosity level.

11. Firewall Settings

In addition to the Windows Firewall, you may need to configure the firewall on the OpenVPN server and the client devices to allow the traffic between them. The rules may depend on the protocol, the port, the source and destination IP addresses, and the type of traffic (e.g., TCP, UDP, ICMP). You should consult the documentation of your firewall software or device for the specific settings.

12. Troubleshooting

If you encounter any issues with the OpenVPN server, you can troubleshoot them by following these steps:

• Check the logs for any errors or warnings.
• Check the firewall settings on the server and the client devices.
• Check the network connectivity between the server and the client devices.
• Check the configuration files for any syntax or spelling errors.
• Update the OpenVPN software to the latest version.
• Consult the OpenVPN community forums for help.

13. FAQ

13.1. What is OpenVPN?

OpenVPN is a free and open-source VPN software that allows you to create a secure and encrypted connection between two or more devices over the internet. It uses SSL/TLS encryption to protect the data in transit from eavesdropping and tampering, and supports various authentication methods, such as certificates, passwords, and two-factor authentication.

13.2. How does OpenVPN work?

OpenVPN works by creating a virtual network interface on the devices and routing the traffic through a secure tunnel. The devices authenticate each other using digital certificates and exchange the encryption keys for the session. The data is encrypted and decrypted on the fly using the agreed cipher and key size. The tunnel can be configured to allow or block certain types of traffic, and to route the traffic through specific gateways or networks.

13.3. Is OpenVPN secure?

OpenVPN is considered to be a secure VPN protocol, as it uses strong encryption algorithms and authentication mechanisms. However, the security also depends on the configuration of the server and the client devices, the handling of the certificates and keys, and the protection of the network infrastructure. You should follow the best practices for securing the OpenVPN deployment, such as