Tunneling (also known as port forwarding) is a way to forward TCP traffic. Any application protocol running over TCP can be tunneled using this service. Client-server applications carry out any authentication procedures just as they do when TCP tunneling is not involved.
Go to Configuration > Services > Proxy Services and create a New Service.
Configure the Proxy Settings to be TCP Tunnel and add relevant listening ports for destination.
Once configured, save this service and ensure it is intercepted.
Now go the Visual Policy Manager and create a rule in Web Access Layer to allow users to access the service.
Please note the ProxySG should be in transparent deployment mode for this service to work.