In a Google sheet this script will read column A where the ddns are and read column c, d, e, f, g where the ports are. Once Nmap shows if up/down it will show the device that's under a port in a comments and change the colors of the cell.
Get api from https://console.developers.google.com/apis/
Share Email from api in sheet 
Download API and put it in root folder
Change index.js API and Sheet ID
Install node.JS https://nodejs.org/en/
Linux: apt install nodejs npm nmap -y
npm install Or npm ci
node index.js
systemctl enable /full_path/foo.timer
systemctl daemon-reload
systemctl enable foo.timer
systemctl start foo.timer
systemctl enable foo.service
systemctl list-timers --all
Linux
Windows
Check prefix in Windows for nmap.
Video for the dummies.
Add 2 new columns of ports in the sheet. Provide at least an explanation.
Add a note of ISP in columns 1 and 2.
If ISP is not empty, then change the color (to avoid forcing online from NMap using -Pn).
Eventually, index.js will go into a cell instead of notes (at least index_cell.js, index_note.js).
ISP - should be stripped to ISP Name in a new cell (for my personal app).
