Lightweight remote port forwarding script/tool

Question

I have a Ubuntu computer behind firewall (Comp-In), with all incoming port blocked. I need to run VNC server there. I have another computer running on Windows, that can freely listen to all ports (Comp-Out) from the internet. I want to use Comp-Out to accept VNC client connection request on-behalf of Comp-In. I don't want SSH server running on Comp-Out (I got tons of strange login attempt once I started a SSH server).

So:

1. Comp-In (port forwarder client) -> Comp-Out (port forwarder server)
2. Comp-Out (port forwarder server) keeps the Comp-In<->Comp-Out tunnel, and listens to other computers' VNC client requests
3. Once VNC connection requests happen, the port forwarder server somehow tells forwarder client to launch a connection to localhost VNC server in Comp-Out, then tunnel all data.

Comp-In is in a remote office, with good internet connection and is switched on all the time. The port forwarder needs to be robust to disconnection. Comp-Out is my home computer, is switched on and off daily. I expect Comp-Out only need to liste to two TCP ports, one for tunnel one act as VNC server.

Had checked with this python scripts https://github.com/git-davi/reverse-python-port-forwarder It doesn't really work because it keeps throwing exception whenever VNC client or the tunnel disconnects.

Any suggestion?