http://www.howtonetworking.com/command/openport1.htm
https://www.howtogeek.com/howto/28609/how-can-i-tell-what-is-listening-on-a-tcpip-port-in-windows/
https://support.rackspace.com/how-to/checking-listening-ports-with-netstat/
CurrPorts Port Tool:
https://www.howtogeek.com/howto/28609/how-can-i-tell-what-is-listening-on-a-tcpip-port-in-windows/