Your client (source side) will use a randomly-assigned port when communicating via RPC. The server (destination) will use a standard port established by the protocol RPC is using. As a test, I tried Snapdrive and from what I can see it's using Named Pipes (port 445).
I'm not sure why you're seeing 443 and 0. I know it's very common to block port 445 on the external side, but is it possible you have a firewall between your client server and the controller that is blocking port 445?