OpenSSH : Using Putty and an HTTP proxy to ssh anywhere through firewalls
From Deimos.fr / Bloc Notes Informatique
Do you ever have the situation (say at work using windows) where you would like to connect to a machine over ssh (say at home using Linux/UNIX) but it's not possible because of firewall rules? There might be an http-proxy server available that you could use.
Be aware that applying this trick might be technically possible but not permitted. Probably best to discuss it with someone in your organization first.
Using Putty and an HTTP proxy to ssh anywhere through firewalls