Sorry if my query / question wasn't clear. I have a web server that hosts a SFTP application. A user will connect through the F5 via HTTPS and log in. On the application interface a user can upload files (much like any SFTP application). The client (user) has a plugin installed which then communicates with the web server to transmit the data. This communication between the client and web server is made over TCP and uses UDP to transmit the data. Hope that clarifies the back-end a bit better.
As I mentioned, I am having an issue that if I have all 4 of my Virtual Server ports enabled (i.e. Primary TCP 12345/Primary UDP 12345 and Secondary TCP 6789/Secondary UDP 6789) the communication between the client and the F5 stop working. If I disable either the Secondary TCP/UDP virtual servers OR I disable the primary TCP/UDP virtual servers then the application will work. How do I get all virtual servers (as a primary / backup configuration) to work at the same time? I am experimenting with policies and round-robin configurations to see if I can get all VS's to work at the same time.