If you mean that JRMP leaks internal IP addresses in the protocol itself for callbacks and thus can't be NATted, that can be fixed with a couple properties to f

If you mean that JRMP leaks internal IP addresses in the protocol itself for callbacks and thus can't be NATted, that can be fixed with a couple properties to force the use of outer-IP DNS: java.rmi.server.hostname=myhostname.com java.rmi.server.useLocalHostname=true You also can tunnel JRMP through HTTP - there was a CGI script called java-rmi dating back to the late 1990's that I think was still distributed through Java 8 (!), and also an RMI Servlet Handler which was a bit more robust/performant. Spring also still has the RmiServiceExporter and HttpInvokerServiceExporter. I remember building Java applets and servers that did fixed income quotes & bond trading systems via streamed encrypted serialized Java objects circa 1999-2000. What a security nightmare, but no one knew better. I feel old.