Find all open connections with port number from your computer

open command prompt and use the command netstat -an.

To filter details for a particular ip , you may use the below syntax :

netstat -an | find ” 192.168.100.1″

Or to check for a specific port netstat -an | findstr “443”

Or to get more details like the process id which is using the port,

Netstat -bano | findstr “443”