Creating a simple DIY VPN (Virtual Private Network) in Python involves setting up a basic client-server architecture that encrypts traffic between the client and server. However, please note that creating a fully secure and robust VPN solution requires a deep understanding of networking, encryption, and security best practices. The code below is a very basic example for educational purposes and should not be used in production or for securing sensitive data.



### Basic DIY VPN in Python

Here’s a basic example using Python's `socket` library and `ssl` for encryption.

#### 1. Server Code (VPN Server)

```python
import socket
import ssl

# Server settings
HOST = '0.0.0.0'  # Listen on all interfaces
PORT = 12345      # Arbitrary port number

# Create socket
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server_socket.bind((HOST, PORT))
server_socket.listen(5)

# Wrap socket with SSL
context = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
context.load_cert_chain(certfile="server.crt", keyfile="server.key")
server_socket = context.wrap_socket(server_socket, server_side=True)

print(f"VPN Server listening on {HOST}:{PORT}")

while True:
    client_socket, addr = server_socket.accept()
    print(f"Connection from {addr}")

    # Receive data from client
    data = client_socket.recv(1024)
    while data:
        print(f"Received: {data}")
        # Echo the data back to the client (simple forwarding)
        client_socket.sendall(data)
        data = client_socket.recv(1024)

    client_socket.close()
```

#### 2. Client Code (VPN Client)

```python
import socket
import ssl

# Server settings
HOST = 'server_ip_address'  # Replace with the server's IP address
PORT = 12345                # Must match the server's port

# Create socket
client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

# Wrap socket with SSL
context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
context.load_verify_locations("server.crt")
client_socket = context.wrap_socket(client_socket, server_hostname=HOST)

# Connect to VPN server
client_socket.connect((HOST, PORT))
print(f"Connected to VPN Server at {HOST}:{PORT}")

# Send and receive data
client_socket.sendall(b"Hello, Server!")
data = client_socket.recv(1024)
print(f"Received from server: {data}")

client_socket.close()
```

### Steps to Run:

1. **Generate SSL Certificates**:
   You need a server certificate (`server.crt`) and a private key (`server.key`). You can generate these using OpenSSL:

   ```bash
   openssl req -x509 -newkey rsa:4096 -keyout server.key -out server.crt -days 365 -nodes
   ```

2. **Run the Server**:
   - Start the VPN server on your server machine.

   ```bash
   python vpn_server.py
   ```

3. **Run the Client**:
   - Run the client on your local machine or another remote machine.

   ```bash
   python vpn_client.py
   ```

### Notes:
- This basic VPN server simply echoes the data back to the client, and it doesn't route traffic through the server. A full VPN would need to handle routing, tunneling, and more complex encryption.
- **Security Warning**: This is a very basic example and is not secure enough for real-world use. VPNs should use well-tested protocols and libraries to ensure the safety and privacy of your data.
- Consider using existing VPN solutions (like OpenVPN) for real-world applications.