WANIP-Alert-Script
Simple linux bash script to notify an email address when it detects a change in WAN-IP address
Requirements: You will need to have setup SMTP Email Notifications on your NAS
Copy then script to your Synology NAS, then setup a scheduled task to run the script. You may want to run the script every 15,30 or 60mins or even just once per day.
The script will create a small file with the ip address of the WAN connection. If the WANIP is different from the previously saved IP address, it will send an Email with the new WANIP address.