Domain MX Record Monitor

A Google Apps Script that monitors MX records for your domains and sends alerts via Google Chat webhook when changes are detected.

Features

• 🔍 Monitors multiple domains for MX record changes
• 🔔 Real-time notifications via Google Chat webhook
• 📊 Tracks MX record history in Google Sheets
• ⏰ Automatic monitoring with configurable check intervals
• 🛡️ Uses Google's DNS API for reliable lookups

Prerequisites

• Google account with access to Google Sheets
• Google Chat space with webhook capability (or Slack as alternative)
• Domains you want to monitor

Installation

1. Create a new Google Sheets spreadsheet

   • Go to Google Sheets
   • Create a new blank spreadsheet
   • Name it something like "MX Record Monitor"

2. Open the Apps Script editor

   • In your spreadsheet, click Extensions → Apps Script
   • Delete any default code in the editor

3. Add the script

   • Copy the entire script from Code.gs in this repository
   • Paste it into the Apps Script editor
   • Click the save icon or press Ctrl+S (Windows) / Cmd+S (Mac)
   • Name the project "MX Record Monitor"

Configuration

1. Configure Your Domains

Edit the CONFIG object in the script:

domains: [
  'example.com',
  'yourdomain.com',
  'anotherdomain.com'
],

Add all domains you want to monitor.

2. Set Up Google Chat Webhook

Create a webhook in Google Chat:

1. Open Google Chat in your browser
2. Create a new Space or select an existing one
3. Click on the space name at the top
4. Select Apps & integrations
5. Click on Webhooks
6. Click Add webhook
7. Name it "MX Monitor" (or any name you prefer)
8. Click Save
9. Copy the webhook URL that appears

Add the webhook URL to the script:

webhookUrl: 'https://chat.googleapis.com/v1/spaces/XXXXXX/messages?key=YYYYYY&token=ZZZZZZ',

3. Adjust Check Interval (Optional)

By default, the script checks every 6 hours. To change this:

checkIntervalHours: 6, // Change to desired hours (1, 2, 4, 6, 8, 12, 24)

Setup and Activation

1. Run the Setup Function

In the Apps Script editor:

1. Select the function dropdown at the top (shows "Select function")
2. Choose setupTrigger
3. Click the Run button (▶️ icon)

2. Authorize the Script

On first run, you'll need to authorize the script:

1. Click Review permissions
2. Select your Google account
3. Click Advanced → Go to MX Record Monitor (unsafe)
4. Click Allow

The script needs these permissions to:

• Access your spreadsheet to store MX record history
• Make external HTTP requests to check DNS records and send notifications
• Create time-based triggers for automatic monitoring

3. Verify Setup

After running setupTrigger:

• Check your Google Sheet - a new tab called "MX_Records" should appear
• You should receive a Google Chat notification with initial MX records
• The script will now run automatically based on your configured interval

Monitoring Dashboard

The script creates a "MX_Records" sheet with the following columns:

Domain	MX Records	Last Checked	Last Changed
example.com	10 mx1.example.com | 20 mx2.example.com	2024-01-15 10:30:00	2024-01-15 10:30:00

Notification Examples

MX Records Changed

🔔 MX Record Monitor Alert

⚠️ example.com - MX RECORDS CHANGED
  Old: 10 mx1.example.com | 20 mx2.example.com
  New: 10 new-mx1.example.com | 20 new-mx2.example.com

Error Detected

🔔 MX Record Monitor Alert

❌ example.com - ERROR
  Failed to fetch MX records: DNS query failed

Initial Setup

🔔 MX Record Monitor Alert

✅ example.com - Initial monitoring setup
  Records: 10 mx1.example.com | 20 mx2.example.com

Testing

To manually test the monitoring:

1. In the Apps Script editor, select the testMXCheck function
2. Click Run (▶️ icon)
3. Check the Execution log (View → Logs) for results
4. Verify you receive a notification if this is the first run

Using Slack Instead of Google Chat

To use Slack webhooks instead:

1. Create a Slack incoming webhook in your workspace
2. Replace the sendNotification function with:

function sendNotification(results) {
  if (!CONFIG.webhookUrl || CONFIG.webhookUrl === 'YOUR_WEBHOOK_URL_HERE') {
    Logger.log('WARNING: Webhook URL not configured');
    return;
  }
  
  let message = ':bell: *MX Record Monitor Alert*\n\n';
  
  results.forEach(result => {
    if (result.status === 'changed') {
      message += `:warning: *${result.domain}* - MX RECORDS CHANGED\n`;
      message += `  Old: ${result.oldRecords}\n`;
      message += `  New: ${result.newRecords}\n\n`;
    } else if (result.status === 'error') {
      message += `:x: *${result.domain}* - ERROR\n`;
      message += `  ${result.error}\n\n`;
    } else if (result.status === 'initial') {
      message += `:white_check_mark: *${result.domain}* - Initial monitoring setup\n`;
      message += `  Records: ${result.records}\n\n`;
    }
  });
  
  const payload = {
    text: message
  };
  
  const options = {
    method: 'post',
    contentType: 'application/json',
    payload: JSON.stringify(payload),
    muteHttpExceptions: true
  };
  
  try {
    const response = UrlFetchApp.fetch(CONFIG.webhookUrl, options);
    Logger.log('Notification sent: ' + response.getContentText());
  } catch (error) {
    Logger.log('Failed to send notification: ' + error.toString());
  }
}

Managing Triggers

View Active Triggers

1. In Apps Script editor, click the clock icon (Triggers) in the left sidebar
2. You'll see all active triggers for this project

Disable Monitoring

1. Go to Triggers
2. Click the three dots next to the checkMXRecords trigger
3. Select Delete trigger

Re-enable Monitoring

Run the setupTrigger function again

Troubleshooting

No notifications received

• Verify webhook URL is correct in the CONFIG object
• Check the Execution log (View → Executions) for errors
• Ensure the Google Chat space allows webhooks
• Run testMXCheck manually to see error messages

"Authorization required" errors

• Re-run the authorization process
• Make sure you clicked "Allow" for all permissions

MX records not updating

• Check that domains are spelled correctly
• Verify domains have MX records (use nslookup -type=mx yourdomain.com)
• Check Execution log for DNS query errors

Script not running automatically

• Go to Triggers and verify a trigger exists for checkMXRecords
• Check execution history for any failures
• Re-run setupTrigger to recreate the trigger

How It Works

1. DNS Lookup: Uses Google's public DNS API (dns.google) to query MX records
2. Storage: Stores current MX records in a Google Sheet
3. Comparison: Compares new results with stored records
4. Notification: Sends webhook notification when changes detected
5. Scheduling: Time-based trigger runs the check automatically

Privacy & Security

• All data is stored in your personal Google Sheet
• DNS queries use Google's public DNS API
• Webhook notifications are sent only to your configured endpoint
• No third-party services have access to your data

License

MIT License - Feel free to use and modify as needed

Contributing

Issues and pull requests are welcome! Please feel free to submit improvements or report bugs.

Support

For issues or questions:

1. Check the Troubleshooting section above
2. Review the Execution log in Apps Script
3. Open an issue on GitHub with error details

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Note: This script is provided as-is. Always test thoroughly before relying on it for critical monitoring.