wssh

Try to proxy SSH connection through Websocket (to use with nginx).

First attemp was using pair of requests (GET+POST), but nginx appeared to always buffering user request (server response can be send back unbuffered). So it is impractical :-(

So, next step was to use Websocket proxying, which is available in nginx since v1.3.13.

Data flow

Normal SSH session is very simple:

• SSH Client
• TCP Connection
• SSH Server, listening on TCP port 22

WSSH session is:

• SSH Client with -o ProxyCommand='node client.js WSSH-URI'
• client.js listening to its stdin
• Websocket (HTTP/HTTPS) connection to nginx
• nginx configured to redirect connection to WSSH server
• Another Websocket connection from nginx to WSSH server
• WSSH server, listening to dedicated TCP port (4567 by default)
• Normal TCP connection
• Normal SSH Server, listening on TCP port 22

And nginx stage can be omited in development/testing scenarios.

In some scenarios this path can be even longer:

• SSH Client, capable to connect via HTTP proxy (eg PuTTY/PLink)
• TCP connection to local proxy
• connect.js listening to dedicated port (3122 by default)
• Websocket (HTTP/HTTPS) connection to nginx
• nginx configured to redirect connection to WSSH server
• Another Websocket connection from nginx to WSSH server
• WSSH server, listening to dedicated TCP port (4567 by default)
• Normal TCP connection
• Normal SSH Server, listening on TCP port 22

Windows bugs

Node.js has some strange bug when working with MS Windows STDIN. Therefore client.js cannot be used as local proxy command for PuTTY/PLink.

So, on MS Windows, one should use connect.js and PuTTY/PLink via HTTP proxy (localhost:3122 by default).

See also

• Ruby port
• Python version

Credits

• nginx
• Node.js
• ws
• OpenSSH
• PuTTY