Without knowing the issue you're trying to solve, it's a tough question to answer. There are 65,535 ports per IP address. If I were trying to remote into a Windows server to connect via Remote Desktop Protocol (RDP) and the server IP is 126.96.36.199, my connection would look like this 188.8.131.52:3389 where 3389 is the port to which RDP is tied.
We list common ports on our Port Scanner page Take a look and see if this helps. https://www.whatismyip.com/port-scanner/