Start a script on a remote machine through ssh with python - but in reverse?

Question

Here's what I need to do:

The user is on a remote machine and connects to a server via ssh. He runs a python script on the server. The script running on the server starts a script on the user's remote machine as a subprocess and opens a pipe to it for communication.

First, is this at all possible?

Second, is this possible in such a way that the user does not need to do anything fancy, like open up a reverse ssh tunnel? If they do have to open up a reverse ssh tunnel, can I figure out which port they are using?

Answer 1

First, is this at all possible?

With simple user --SSH--> server - no, its not.

is this possible in such a way that the user does not need to do anything fancy

User will have to run sshd on his machine, add a user for your server and somehow let you to connect to it, bypassing NAT if any. So no, there is no such way with SSH.

I'd go with client-side application. Give script to user and let him run the script instead of SSH'ing. If you need to communicate with server, you can use something like paramiko on client side to connect to server from script. Then, script can launch other applications on client's computer based on data it receives from server.