Just to clarify...
In SMP3.0, your agentry apps still support reverse proxy connections from your clients. If the reverse proxy is setup for TCP pass through traffic (just as for Agentry or SMP 2.3) it will route and work just fine with SMP 3.0. Additionally, in SMP 3.0 the Agentry connections are swtiching to websocket based connections so that you can potentially also use an HTTPS proxy like the relay server.
While I have not yet used the relay server with SMP 3.0 Agentry applications, I have tested my Agentry applications behind a reverse proxy using TCP passthrough and they work as expected.
--Bill