Remote access FDB in private subnet behind NLB

Foundation db cluster is deployed in private subnet and NLB in public subnet is used to loadbalance to the cluster. Is it possible to use NLB public IP in FDB client side cluster file ( client is in onpremis ) and access FDB in private subnet ?

I think that’s currently not possible and the way how FDB works today is that all clients must be able to connect to all processes (there is probably an exception to log processes) in the cluster. You either have to deploy your application inside the private subnet, create a VPC peering (or something like that) or you create a server application that exposes the FDB functionality inside the private subnet and expose this server with the NLB (e.g. GitHub - panghy/lionrock: gRPC Facade for Transactional Keyvalue Stores if you use gRPC (spoiler: I haven’t used lionrock)).

For my knowledge, what is the protocol foundation db client and foundation db server use to communicate ?
Can I make all nodes in cluster as coordinators and loadbalance the traffic to all of them ?