root access - possible to ssh into android phone over 3G?

Is it possible to run an ssh shell on an android phone when the phone is remotely connected but on 3G? I have my phone remote and sending data over 3G but I might want to change something on it. I have considered

1) the phone receiving text back from an http request and riunning it as a connad 2) running an ssh shell on the phone anything else?

Thanks