6.2.2. SSH Tunnel#

Available since version 3.7.0

Vantage6 algorithms are normally disconnected from the internet, and are therefore unable to connect to access data that is not connected to the node on node startup. Via this feature, however, it is possible to connect to a remote server through a secure SSH connection. This allows you to connect to a dataset that is hosted on another machine than your node, as long as you have SSH access to that machine.

An alternative solution would be to create a whitelist of domains, ports and IP addresses that are allowed to be accessed by the algorithm.

Setting up SSH tunneling#

1. Create a new SSH key pair#

Create a new key pair without a password on your node machine. To do this, enter the command below in your terminal, and leave the password empty when prompted.

ssh-keygen -t rsa

You are required not to use a password for the private key, as vantage6 will set up the SSH tunnel without user intervention and you will therefore not be able to enter the password in that process.

2. Add the public key to the remote server#

Copy the contents of the public key file (your_key.pub) to the remote server, so that your node will be allowed to connect to it. In the most common case, this means adding your public key to the ~/.ssh/authorized_keys file on the remote server.

3. Add the SSH tunnel to your node configuration#

An example of the SSH tunnel configuration can be found below. See here for a full example of a node configuration file.

  httpserver: http://my_http:8888
  - hostname: my_http
      host: my-remote-machine.net
      port: 22
      fingerprint: "ssh-rsa AAAAE2V....wwef987vD0="
        username: bob
        key: /path/to/your/private/key
        port: 8888
        port: 9999

There are a few things to note about the SSH tunnel configuration:

  1. You can provide multiple SSH tunnels in the ssh-tunnels list, by simply extending the list.

  2. The hostname of each tunnel should come back in one of the databases, so that they may be accessible to the algorithms.

  3. The host is the address at which the remote server can be reached. This is usually an IP address or a domain name. Note that you are able to specify IP addresses in the local network. Specifying non-local IP addresses is not recommended, as you might be exposing your node if the IP address is spoofed.

  4. The fingerprint is the fingerprint of the remote server. You can usually find it in /etc/ssh/ssh_host_rsa_key.pub on the remote server.

  5. The identity section contains the username and path to the private key your node is using. The username is the username you use to log in to the remote server, in the case above it would be ssh bob@my-remote-machine.net.

  6. The tunnel section specifies the port on which the SSH tunnel will be listening, and the port on which the remote server is listening. In the example above, on the remote machine, there would be a service listening on port 9999 on the machine itself (which is why the IP is a.k.a. localhost). The tunnel will be bound to port 8888 on the node machine, and you should therefore take care to include the correct port in your database path.

Using the SSH tunnel#

How you should use the SSH tunnel depends on the service that you are running on the other side. In the example above, we are running a HTTP server and therefore we should obtain data via HTTP requests. In the case of a SQL service, one would need to send SQL queries to the remote server instead.


We aim to extend this section later with an example of an algorithm that is using this feature.