On the client computer:
1. The firewall must be configured to allow external connections to the IP / Port.
2. The router must allow external connections to the external IP/port.
On the server computer.
1. The firewall must be configured to allow incoming / outgoing connection on the Port configured (this happens when you install the TurboFloat Server on Windows, see: https://wyday.com/limelm/help/turbofloat-server/#install ) On other operating systems you must handle the various firewalls yourself.
2. The router and any network switches must be configured to allow incoming / outgoing connections on the Port, and if multiple computers share the IP, then data on that Port must be forwarded correctly to that server computer.