locknet is a simple firewall/proxy script you can use to tunnel all your network traffic through a single SSH connection. When you run it, it tells iptables to block all network traffic except to the IP/port of your proxy host, opens an SSH connection to that host with DynamicForward 1080 (and my own LocalForwards, which you probably want to change), and changes GNOME's proxy settings to use it. When you kill locknet, the connection dies and it restores your old network settings.