Is a free online tool to find open ports in your system. You can also test whether port forwarding is working or not.
https://hackertarget.com
vankyver
https://myopenports.com
FreeMedian
https://isnorcreative.com
jorge.silva.jetter
Ludovic COULON & Riadh BOUCHAHOUA
0140454
acc+browserext
Lacework
Bohumil Beran
https://garywill.github.io