VPN-Network-Checker: VPN Device Monitoring with Telegram Alerts

Description:

This application monitors device availability within a VPN network using ICMP (ping) requests and sends notifications to a designated Telegram chat. It's designed to help maintain device uptime and promptly alert you to any disconnections or outages.

Key Features:

• Network Scanning: Discovers accessible devices within a specified IP address range.
• Periodic Monitoring: Regularly checks the availability of found devices.
• Telegram Notifications: Pushes real-time alerts for device availability and unavailability.
• WhiteList: Filters monitoring to a defined set of critical devices for focused attention.
• Customizable Settings: Allows tailoring the application's behavior to specific needs updating the config.properties file

Configurable Parameters (Config class):

• TIMEOUT: Wait time for ICMP response in milliseconds.
• INITIAL_DELAY: Initial delay before starting periodic checks in minutes.
• PERIOD: Interval between device checks in minutes.
• MAX_RETRY_ATTEMPTS: Maximum retries for device checks upon failure.
• NET_IP_ADDRESS: Base IP address of the subnet to scan.
• NET_MASK: Subnet mask for calculating the IP address range.
• TELEGRAM_BOT_TOKEN: Token of your Telegram bot (set in application.properties).
• TELEGRAM_CHAT_ID: ID of the Telegram chat to receive notifications (set in application.properties).

Setup and Usage:

1. Configure Settings:

• Modify values in the config.properties as needed.
• Add your Telegram bot token and chat ID to application.properties. 2)Compile JAR File:
• Open a terminal in the project's root directory.
• Run: javac -d out/artifacts/VPNnetworkChecker src/org/netchecker/*.java

3. Set Up Service (Linux):

• Edit VPNnetworkCheck.service in out/artifacts:
  • Provide correct path to JAR file.
  • Adjust other startup parameters if needed.
• Copy the service file to /etc/systemd/system.
• Run: systemctl daemon-reload and systemctl start VPNnetworkCheck.service

4. Run on Windows:

• Open a terminal in the folder containing the JAR file.
• Run: java -jar VPNnetworkChecker.jar

Important! Compiled jar file and config.properties have to be placed in the same directory!

5. Connect to VPN:

• Ensure the server or machine is connected to your organization's VPN.

Initiate Monitoring:

• Once launched, the application will initiate device scanning, periodic checks, and Telegram notifications.

Alerts example: