PyCharm multi-hop ssh configuration

Question

This is how I remotely access my personal workstation with GPUs:

Local computer (mac-mini) --> SSH --> Gate Server --> SSH --> Workstation

For example, to use Jupyter Notebook on my local computer, I use the following command in the terminal:

ssh -L 6000:127.0.0.1:6000 username@gate.server.address

And then type 127.0.0.1:6000 in the web browser.

This works because Jupyter Notebook is running on port 6000 on my workstation, and on the Gate Server, the port is forwarded as:

ssh -L 6000:127.0.0.1:6000 workstation

I tried using PyCharm for debugging in this situation.

I followed the steps as in: PyCharm: Configuring multi-hop remote Interpreters via SSH

1. opened a terminal in my local computer

   ssh -L 6000:workstation:22 username@gate.server.address
   

2. configure PyCharm

   • host: localhost

   • port: 6000

   • user: username

However, it was not connected to my workstation, presumably somewhere in the Gate Server, and failed to find where Python was installed on my workstation.

Therefore, I also changed my ./.ssh/config as follows:

Host workstation     
  HostName workstation
  User username
  ProxyCommand ssh -q -W %h:%p gate 
  KexAlgorithms +diffie-hellman-group1-sha1
    
Host gate
  HostName gate.server.address
  User username 
  IPQoS=throughput
  KexAlgorithms +diffie-hellman-group1-sha1

And configure PyCharm:

• host: workstation

• port: 22

• user: username

This time, the error message popped up that failed to connected to workstation:22.

Lastly, on the Gate Server, I tried portforwarding as follow:

ssh -L 22:127.0.0.1:2323 workstation

And it was denied becasue "privileged ports can only be forwarded by root".

My Questions are:

1. What is the best SSH tunneling set up/PyCharm configuration in this situation?

2. Using VPN is necessary?