VPN and Tor Management Script Overview

This document provides a detailed explanation of the Bash script that manages VPN and Tor services. It includes descriptions of functions, processes, and overall workflow to help understand how each component works.

Table of Contents

1. Overview
2. Script Functions
   • reset_to_dhcp
   • configure_dns
   • check_vpn
   • terminate_vpn
   • start_vpn
   • restart_tor
   • check_tor_connection
   • stop_vpn_and_tor
   • monitor_connections
3. Process Flow
4. Execution and Monitoring
5. Conclusion

Overview

This Bash script manages VPN and Tor connections, ensuring that the network configurations are dynamically adjusted based on the status of each service. It also monitors the VPN connection and Tor service stability and re-establishes them when necessary.

The script uses DNS configurations and specific service management commands to ensure network privacy and connectivity. It automates the process of connecting, disconnecting, and monitoring the VPN and Tor services.

Script Functions

reset_to_dhcp

• Description: Resets DNS settings and switches back to DHCP configuration.
• Process:
  1. Unsets the immutable attribute on the /etc/resolv.conf file.
  2. Sets the DNS to a local fallback DNS address.
  3. Re-enables DHCP client to refresh IP and DNS configuration.
  4. Makes /etc/resolv.conf immutable again to prevent unauthorized changes.

sudo chattr -i /etc/resolv.conf
echo "nameserver $local_dns" | sudo tee /etc/resolv.conf
sudo dhclient -r && sudo dhclient
sudo chattr +i /etc/resolv.conf

configure_dns

• Description: Configures DNS settings for use with VPN or Tor.
• Process:
  1. Makes /etc/resolv.conf file writable.
  2. Sets the DNS to the preferred DNS address.
  3. Sets /etc/resolv.conf back to immutable.

sudo chattr -i /etc/resolv.conf
echo "nameserver $desired_dns" | sudo tee /etc/resolv.conf
sudo chattr +i /etc/resolv.conf

check_vpn

• Description: Checks if the VPN is currently running by looking for the tun0 network interface.
• Process: Uses ip a | grep tun0 to determine if the VPN is active.

vpn_interface=$(ip a | grep tun0)

terminate_vpn

• Description: Terminates any existing OpenVPN sessions.
• Process:
  1. Stops the OpenVPN service if it is managed by systemd.
  2. Kills all existing OpenVPN processes manually.
  3. Verifies that no OpenVPN processes are running.

sudo systemctl stop openvpn
sudo pkill -9 -f openvpn

start_vpn

• Description: Starts the OpenVPN client using a specified configuration file and credentials.
• Process:
  1. Checks if OpenVPN is already running.
  2. Starts the OpenVPN client.
  3. Verifies VPN connectivity by checking for the tun0 interface.

sudo openvpn --config "$vpn_config" --auth-user-pass "$vpn_credentials" &

restart_tor

• Description: Restarts the Tor service to ensure connectivity.
• Process: Uses sudo systemctl restart tor and allows time for the service to stabilize.

sudo systemctl restart tor

check_tor_connection

• Description: Validates the Tor connection by using proxychains and curl to check the Tor project's connection verification page.
• Process:
  1. Uses proxychains curl -s https://check.torproject.org.
  2. Looks for the "Congratulations" message to verify a successful connection.
  3. Restarts Tor if the connection is not established.

proxychains curl -s https://check.torproject.org

stop_vpn_and_tor

• Description: Stops both the VPN and Tor services and resets DNS settings.
• Process:
  1. Terminates VPN and Tor services.
  2. Kills any proxychains processes.
  3. Resets DNS to local settings.

terminate_vpn
sudo killall proxychains
sudo systemctl stop tor
reset_to_dhcp

monitor_connections

• Description: Monitors VPN and Tor connections and re-establishes them if needed.
• Process:
  1. Periodically checks the status of the VPN and Tor services.
  2. Restarts VPN and Tor services if connectivity is lost.

vpn_up=$(ping -c 1 -W 3 10.8.0.1)
tor_connected=$(proxychains curl -s https://check.torproject.org)

Process Flow

1. Script Initialization:

   • The script begins by invoking the monitor_connections function.

2. VPN and DNS Configuration:

   • start_vpn is called to establish a VPN connection using the provided configuration file and credentials.
   • If the VPN connection is successful, DNS is configured using configure_dns.

3. Tor Service Management:

   • Tor is restarted using the restart_tor function.
   • The Tor connection is validated using check_tor_connection.

4. Continuous Monitoring:

   • The script enters a continuous monitoring state using monitor_connections, periodically checking the status of both the VPN and Tor.
   • If either connection is lost, the script attempts to re-establish connectivity.

Execution and Monitoring

To run this script, execute it as a Bash script:

./vpn_tor_script.sh

Logging and Output

The script uses different symbols to indicate the status of each process:

• [ ಠ‿ಠ ] : Success indicator
• [ (⊙_☉) ] : Informational message
• [ ୧༼ಠ益ಠ༽୨ ] : Error or alert message

These messages help differentiate between normal operations and issues that may require attention.

Conclusion

This Bash script automates the process of managing VPN and Tor services, ensuring consistent connectivity and security. By monitoring the services in real-time and re-establishing connections as needed, the script provides robust network management and privacy.