https://www.grc.com/intro.htm
It has several interesting tool, one of them it permit to check, on line open ports on your pc, public Firewall, Router, Server etc. etc.:
Open the link
“http://www.grc.com”
• click on “ShieldsUP!!” link
• click on “ShieldsUP!” link
• click on “Proceed” button
click on “All Service Port” button
Here it is direct tool link:
https://www.grc.com/x/ne.dll?bh0bkyd2
And here it is an easy video that drive you, step by step, on relative usage:
[2019.05.23 - Port checks]
If you need to check ports on remote public ip that is different from your network connectivity you could use below link:
