🔐 VPN-ClientServer-TLS

A fully secure Python-based VPN with TLS encryption, multi-client communication, message/file transfer, and a Streamlit UI for real-time control and monitoring.

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🚀 Features

• ✅ TLS-secured communication with client/server certificates
• 👥 Multi-client support with unique nicknames
• 💬 Broadcast and private messaging
• 📁 Secure file transfer with binary-safe communication
• 🔁 Heartbeat mechanism to auto-disconnect idle clients
• 📊 Real-time logging and monitoring via Streamlit
• 🧠 Simple and extensible codebase

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🗂️ Project Structure

VPN-ClientServer-TLS/
├── ca_cert.pem             # Certificate authority (optional)
├── client_cert.pem         # Client TLS certificate
├── client_key.pem          # Client TLS private key
├── server_key_1.pem        # (Unused/backup key)
├── server_key.pem          # Server TLS private key
├── vpn_client_tls.py       # TLS-enabled client script
├── vpn_server_tls.py       # TLS-enabled server script
├── vpn_ui1.py              # Streamlit UI for managing client/server
├── vpn_client_tls.log      # Client log (auto-generated)
├── README.md               # You're here!

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💻 Requirements

• Python 3.8 or above
• Install dependencies:

pip install streamlit

🔒 ssl is built-in in Python, no need to install separately.

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📜 TLS Certificate Setup

If not using pre-included certs, generate your own using OpenSSL:

# Server cert + key
openssl req -new -x509 -days 365 -nodes -out server_cert.pem -keyout server_key.pem

# Client cert + key
openssl req -new -x509 -days 365 -nodes -out client_cert.pem -keyout client_key.pem

⚠️ Ensure the server and client trust each other's certificates.

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🛠️ How to Run

1. Start the Server

python vpn_server_tls.py

OR with Streamlit UI:

streamlit run vpn_ui1.py

2. Start a Client

python vpn_client_tls.py

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💬 Messaging Syntax

• Broadcast: Just type and send your message.
• Private: Use @username message to send a private message.

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📁 File Transfer

• Clients can send files securely through the server.
• Files are stored in the same directory under the sender's name.
• Works for all file types (binary-safe).

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🔧 How It Works

• 🔐 TLS Layer: The server uses ssl.wrap_socket() to securely wrap its socket using its certificate and key. Clients verify the server using its certificate.
• 👥 Client Registration: Each client sends a unique nickname upon connection. The server manages a list of active clients.
• 💬 Communication: All messages and files are sent through the server. It handles broadcast or private delivery based on message format.
• 🗂 File Transfer: Files are read in binary mode and securely relayed from one client to another through the server, preserving integrity.
• 🧠 Heartbeat Thread: The server sends periodic pings and disconnects unresponsive or idle clients.
• 📊 Streamlit UI: Provides a dashboard to monitor active clients, logs, and control the server directly via web browser.

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🔄 Heartbeat Monitoring

The server automatically pings clients and disconnects idle/inactive users to preserve resources.

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📈 Logging

• Logs are saved as vpn_client_tls.log.
• Tracks all message transfers, file transfers, client events, and errors.

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✅ Tested On

• ✅ Windows 10/11
• ✅ WSL (Ubuntu 20.04)
• ✅ Python 3.8+ and 3.11+

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📌 To Do

• Add authentication prompt in UI
• Add compression to file transfers
• Show file transfer status in GUI
• Use public CA for production TLS setup