I need a solution that will work **without jailbreaking**, but answers that include that can help others are welcome but just might not be selected as *the* answer.

On Linux and on OSX, I use ssh on the command-line to open ssh tunnels so I can run client-server applications securely.

I need to do the equivalent on ios (run some kind of tunnel in the background, while I run a client application through that tunnel).

What tools or options exist and listing supported iOS versions would be even more helpful if you can provide that level of detail.

How can I set up a ssh tunneling service on iOS?