If you need to figure out whether a port is open between two machines in the firewall, Telnet is a useful program commonly referenced at my employer.
The format for the command in Windows is: telnet <address> <port>. A successful connection is just a blank command window with a blinking cursor on Windows, otherwise you should receive an error message.
To learn more about using Telnet, or installing it on your device, I liked Code42's helpful documentation on Telnet for both using and installing it on your operating system, including Mac's and Linux.
