Lab07: SEED 2.0 VPN Tunneling Lab - Part I

Introduction

This tutorial provides a comprehensive guide to creating a VPN using Python and Scapy, along with Docker networking. You'll learn how to set up multiple networks, create a VPN client and server, and establish routing rules to facilitate communication across networks. This guide is relevant for network engineers, cybersecurity enthusiasts, and anyone interested in understanding VPN technologies.

Step 1: Create Multiple Networks in Docker

• Use Docker to set up isolated networks for your VPN.
• Run the following commands to create two separate networks:

  docker network create network1
  docker network create network2
  

Step 2: Protect Computers in Private Network

• Ensure devices within your Docker networks are secured.
• Implement firewall rules and access controls to limit exposure.

Step 3: Create VPN Client with Python and Scapy

• Install Scapy if not already installed:

  pip install scapy
  

• Write a Python script to initialize the VPN client.
• Example structure of the script:

  from scapy.all import *
  
  def create_vpn_client():
      # VPN client code here
      pass
  

Step 4: Create VPN Server with Python and Scapy

• Similarly, create a VPN server script.
• Basic structure:

  from scapy.all import *
  
  def create_vpn_server():
      # VPN server code here
      pass
  

Step 5: Set Up Routing Rules Between Networks

• Use the following commands to set routing rules:

  ip route add <destination_network> via <gateway>
  

Step 6: Route Packets Through VPN Client and Server

• Ensure packets are routed correctly using the VPN client and server.
• Implement packet forwarding in your scripts.

Step 7: Set Up VPN Network Using Client and Server

• Start both the VPN client and server.
• Connect them using the established routes to form a VPN network.

Step 8: Test VPN Network

• Use tools like ping to check connectivity between networks.
• Example command:

  ping <IP_address_of_remote_host>
  

Step 9: Ping Computers Inside a Private Network Behind a Router

• Ensure that your routing rules allow pings to pass through.
• Test connectivity to the private network using:

  ping <private_IP>
  

Step 10: Telnet into Computers Inside a Private Network

• Confirm that the VPN connection is active.
• Use telnet to access devices:

  telnet <private_IP>
  

Step 11: Create TUN Interface in Python and Scapy

• Use Scapy to create a TUN interface for the VPN.
• Example code:

  tun = TunTap()
  tun.open('tun0')
  

Step 12: Configure TUN Interface Using Commands and Python

• Use the following command to configure the TUN interface:

  ip addr add <IP_address> dev tun0
  

Step 13: Read from and Write to TUN Interface in Python

• Implement reading and writing in your Python scripts:

  def read_tun_interface(tun):
      packet = tun.read()
      # Process packet
  

Step 14: Send IP Packets to VPN Server Through a Tunnel

• Ensure packets are encapsulated properly before sending.

Step 15: Set Up VPN Server Using Commands and Python

• Run the server script and ensure it listens for incoming VPN connections.

Step 16: Handle Traffic in Both Directions Between VPN Client and Server

• Use Python's select module to manage incoming and outgoing traffic:

  import select
  
  rlist, wlist, xlist = select.select([client_socket], [], [])
  

Step 17: Ensure Telnet Survives a Temporarily Broken VPN Tunnel

• Implement reconnection logic in your telnet sessions to handle temporary disconnections.

Conclusion

In this tutorial, you learned how to set up a VPN using Docker, Python, and Scapy. Key steps included creating networks, implementing a VPN client and server, and ensuring proper routing. With these foundations, you can further explore advanced networking concepts or enhance your VPN setup for specific use cases.