The tunnel is available by making an ssh connection to the port on the server localhost interface. On the restricted machine, create an ssh key pair in /etc/sshtunnel/ with an empty/no pass-phrase:Įnter fullscreen mode Exit fullscreen modeĮxternal public access via server (optional)įor most users, the above configuration is completely sufficient. So autossh is not required, we can implement an automatically maintained ssh tunnel using standard ssh and systemd alone. Note that autossh was previously often used for this (and nearly all existing online tutorials about reverse ssh tunnels use autossh) but autossh is redundant nowadays since modern openssh versions can monitor link health and exit if the link fails, and systemd can then be used to restart the ssh tunnel. Of course you should always check you have permission to do this with whoever controls the restricted network. With the reverse tunnel in place, you can simply ssh to that port on your server to get a tunnelled ssh session back to the restricted machine through the restricted firewalls. This post describes how you can set up a reverse ssh tunnel initiated and maintained from that restricted machine to a port on a Linux server elsewhere on the internet that you control. Let's call that the restricted machine and we assume you can make changes to it, e.g. Say you have a Linux machine to which you want to ssh to but that machine is behind corporate or other firewalls etc which you have no control over, and thus you can not forward an external port for ssh etc. In the case of this example, where the endpoint is a web server, the browser can be used to navigate to SSHServer:7777 in order to view the webpage.I did not find a clear modern description of this set-up so have written this post to help others. Once started, the endpoint can be reached by connecting to Listening Host. Once the SSH Reverse Tunnel has been added to PowerShell Server, click Start in the toolstrip at the top to start the server and establish the SSH Reverse Tunnel.
Once the necessary information has been entered, the Test SSH Connection button may be used to test the connection to the SSH server in order to verify the validity of the information provided. Forwarding Port is the port on which the tunneled traffic will be forwarded.Forwarding Host is the host where the tunneled traffic will be forwarded.Listening Port indicates the port on which the SSH server will listen for the tunneled traffic.This value is read-only and purely informational. Server Fingerprint indicates the SSH host key fingerprint of the server.SSH Client Key is the certificate PowerShell Server will use to authenticate to the SSH server during Public Key authentication.
Remote SSH Host is the SSH server that PowerShell Server will connect to in order to establish the SSH Reverse Tunnel.This guide only covers SSH Reverse Tunnels. Plaintext, SSL, and SSH Reverse Tunnels are supported. Tunnel Type indicates the type of tunnel.Tunnel Name provides a friendly name for the tunnel.Enabled indicates whether the tunnel should be active or not.