@Andreas, Since you don’t have a Raspberry Pi, I put together a script which could help you out.
You didn’t specify if you were on Windows or Mac or Linux, so I put together a PowerShell script that’ll run on Windows.
You will need to run it using Scheduled Tasks. Run it once a day (or twice a day, whatever you want). It will check your external IP address and log it to c:\ip.txt. When the script runs again, it’ll compare your external IP to the saved text file IP. If they do not match, then your IP has changed.
If it detects that your IP changed, it’ll send you an email.
Requirements:
1. Windows
2. A GMail account to send the email from. Unless you have your own SMTP server, then that can be used instead.
Simply copy and paste the script to your computer and run it with PowerShell (e.g. from command line or Scheduled Task: powershell.exe & “c:\Check_External_IP.ps1”).
Here’s a link to the script: https://gist.github.com/drsprite/6b172d1698b42edcef5c
Hope this helps!