I have a work machine (workMachine) behind a university firewall and a laptop (laptopMachine) which I frequently move around and is often behind a different firewall. I would like to syncthing between these two machines. I can ssh into a university gateway (gatewayMachine) from workMachine and laptopMachine. However, due to the strict nature of the university firewall I cannot ssh from gatewayMachine into workMachine, nor can I rely on being able to ssh into laptopMachine from gatewayMachine. In summary I can make ssh connections consistent only with the arrows here:
laptopMachine -> gatewayMachine <- workMachine
I have tried to setup an ssh tunnel to allow me to syncthing between the two machines as follows.
1) On workMachine setup a reverse port forward, to forward connections to port 22001 on gatewayMachine to port 22000 on workMachine:
workMachine$ ssh -R 22001:localhost:22000 gatewayMachine
2) On laptopMachine setup a local port forward, to forward connections to port 22002 on laptopMachine to port 22001 on gatewayMachine:
laptopMachine$ ssh -L 22002:localhost:22001 gatewayMachine
3) On laptopMachine instruct the syncthing server to discover the workMachine syncthing "remote device" by adding tcp://localhost:22002 to the Addresses field in the Edit Device dialogue of the configuration web server.
This does not seem to be enough to establish a connection. I'd be very grateful for any help or pointers to what I am doing wrong. I can successfully connect to a VNC server running on workMachine from laptopMachine using a similar pair of port forwardings.