Breaking Firewalls with OpenSSH and PuTTY

If the system administrator deliberately filters out all traffic except port 22 (ssh), to a single server, it is very likely that you can still gain access other computers behind the firewall.

This article shows how remote Linux and Windows users can gain access to firewalled samba, mail, and http servers. In essence, it shows how openSSH and PuTTY can be used as a VPN solution for your home or workplace, without monkeying with the firewall.

This article is NOT suggesting you close port 22. These step are only possible given valid accounts on all servers. But, read on, you may be surprised what you can do, without punching additional holes through the firewall -- punching additional holes is a bad idea.