To connect your VFC call recorder to an Intelligent Voice server, you need to permit access on port 443 on the IV server. This is the only port that is used for communication. All requests are made outbound from the VFC server to the IV server. The IV server does not require any ports to be open on the VFC server.
If you deploy multiple IV servers, each additional server will connect to the first on both port 443 and port 4730. Port 4730 is only for internal communication when you have multiple IV servers and is not used by VFC.