Implementing Multi-Instance OpenVPN with Socks Proxy for Secure Web Browsing

In this guide, we’ll walk through the process of setting up a network configuration where clients connect to different OpenVPN instances, each with its own set of private IP addresses, and route their traffic through a SOCKS proxy for secure web browsing.

Introduction

The scenario involves multiple OpenVPN instances running on a server, each listening on different ports. Each OpenVPN instance allocates a separate private IP network for its clients (e.g., 192.168.1.0 for OpenVPN 1 and 192.168.2.0 for OpenVPN 2). The objective is to route client traffic through their respective OpenVPN instances and then through a SOCKS proxy before accessing the web.

Prerequisites

• Server with multiple OpenVPN instances installed
• SOCKS proxy server
• Basic knowledge of networking and server administration

Step 1: Configure OpenVPN Instances

1. Ensure that each OpenVPN instance is configured correctly with its own set of private IP addresses.
2. Make a note of the IP range allocated to each OpenVPN instance (e.g., 192.168.1.0/24 for OpenVPN 1 and 192.168.2.0/24 for OpenVPN 2).

Step 2: Configure SOCKS Proxy

1. Set up a SOCKS proxy server on the same machine or a different server accessible from the OpenVPN instances.
2. Note down the SOCKS proxy server’s IP address and port.

Step 3: Route Traffic

1. Use firewall rules or routing tables to route traffic from each OpenVPN instance through the corresponding SOCKS proxy.
2. Configure the firewall to redirect traffic from OpenVPN 1 clients to SOCKS proxy 1 and traffic from OpenVPN 2 clients to SOCKS proxy 2.

Example Configuration (iptables)

# Redirect traffic from OpenVPN 1 clients to SOCKS proxy 1
iptables -t nat -A PREROUTING -i tun0 -p tcp --dport 80 -j REDIRECT --to-ports <SOCKS_PROXY_1_PORT>

# Redirect traffic from OpenVPN 2 clients to SOCKS proxy 2
iptables -t nat -A PREROUTING -i tun1 -p tcp --dport 80 -j REDIRECT --to-ports <SOCKS_PROXY_2_PORT>

Step 4: Testing

1. Connect clients to their respective OpenVPN instances.
2. Ensure that traffic is routed through the SOCKS proxy by checking the proxy server logs or using network monitoring tools.
3. Test web browsing to verify that clients can securely access the web through the configured setup.

Conclusion

By following these steps, you can implement a network setup where clients connect to different OpenVPN instances with distinct private IP ranges and route their traffic through corresponding SOCKS proxies for secure web browsing. This configuration ensures isolation and enhances security for each client group.