Ok I need to be even more spesific.
My server runs several services; confluence, wordpress, syncrify server and other web-applications and they all are visible on the internet at the same ip-address and port, the only that differ them is the dns-name. nginx are resolving the names and forward to the appropriate internal service at the correct port.
Please tell me how it's own reverse proxy works. It did not work on my machine...
If I enter the JRiver Library Server access key, I see the Gizmo is trying to connect on the correct external ip-address, but at the wrong port (52199). It should try port 80. But even then it cannot work, as the are several services at the same ip-address and port, and the nginx need the dns-host name to route correctly. No Firewall would normally allow browing on port 52199 ...
The nginx solution is free, simple, fast and IMHO perfect ...