PortWatcher

Monitors port reachability with notifications via Telegram and Gotify

This script monitors the reachability of a specific port on a given IP address. If the port becomes unreachable, it sends notifications about the port's status via Telegram and Gotify, avoiding repeated alerts until the port is reachable again. Upon recovery, a notification is sent, and monitoring continues.

Port Monitoring Script

This script monitors the reachability of a specific port on a server and sends notifications via Telegram and Gotify when the port is unreachable or back online.

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Prerequisites

Before starting, ensure you have:

1. Bash Installed

   • Linux/macOS systems already include Bash.
   • For Windows, install WSL or use Git Bash.

2. Telegram Setup

   • Create a Telegram bot and obtain its API token by following this guide.
   • Get your Telegram chat ID using the Telegram bot API.

3. Gotify Setup

   • Set up a Gotify server (instructions).
   • Obtain a valid Gotify app token.

4. Dependencies

   • Ensure the nc (Netcat) and curl commands are installed:

     sudo apt install netcat curl   # For Debian/Ubuntu
     sudo yum install nc curl       # For CentOS/RHEL

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Configuration

1. Clone or Download the Script

   • Clone this repository or download the port_monitor.sh file.

2. Edit the Script Open port_monitor.sh in a text editor and replace the placeholder values with your own:

   • IP/Hostname and Port to Monitor:

     ipToCheck="your-server-address.com"   # Replace with the server address or IP you want to monitor
     portToCheck=22                     # Replace with the port number you want to check

   • Telegram Credentials:

     telegramToken="YOUR_TELEGRAM_BOT_TOKEN"  # Replace with your Telegram bot API token
     telegramChatId="YOUR_TELEGRAM_CHAT_ID"  # Replace with the Telegram chat ID

   • Gotify Credentials:

     gotifyServer="http://your-gotify-server.com"  # Replace with your Gotify server URL
     token="YOUR_GOTIFY_APP_TOKEN"                 # Replace with your Gotify app token

   • Time Settings (optional):

     timeoutSeconds=5   # Time in seconds to wait for a connection
     intervalMinutes=8  # Time in minutes between checks

3. Save the File

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Usage

1. Make the Script Executable Run the following command to give the script execution permissions:

   chmod +x port_monitor.sh

2. Run the Script Execute the script using:

   ./port_monitor.sh

   You can use screen too

   screen -dmS PortWatcher ./port_monitor.sh

3. Press Ctrl+C to stop the script. It will terminate cleanly and stop monitoring.

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Notifications

• Down Alert: When the monitored port becomes unreachable, notifications will be sent via Telegram and Gotify.
• Recovery Alert: When the port is back online, a recovery notification will be sent.

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Troubleshooting

1. Error: Command Not Found

   • Ensure nc (Netcat) and curl are installed:

     sudo apt install netcat curl   # For Debian/Ubuntu
     sudo yum install nc curl       # For CentOS/RHEL

2. Telegram Not Sending Messages

   • Double-check the telegramToken and telegramChatId values.
   • Test your bot by visiting this URL in your browser:

     https://api.telegram.org/bot<YOUR_TELEGRAM_BOT_TOKEN>/sendMessage?chat_id=<YOUR_CHAT_ID>&text=TestMessage
     

3. Gotify Not Sending Messages

   • Ensure your Gotify server is running and accessible.
   • Verify your app token and server URL.

4. Script Not Running

   • Ensure the script has executable permissions:

     chmod +x port_monitor.sh

   • Make sure you're running the script in a Bash-compatible terminal.