Firepass

Firepass is a tunneling tool, allowing to bypass firewall restrictions and encapsulate data flows inside legal ones to use HTTP POST requests. TCP or UDP based protocols may be tunneled with Firepass. For now, both - client and server parts are written in Perl and the server script acts as a CGI program.

You do not need to bind any port on the external box. Firepass may also be usable for the reverse task, when the server script is located at the corporative web server and when client interact with it from the external network.

To run FIREPASS you'll need the following:
- A box located inside your local network, with Perl and the ability to send HTTP messages to the external network (Internet), either directly or indirectly through a HTTP proxy
- A HTTPd server located on the external network (with Perl also) where you can place / run CGI scripts and establish outgoing connections (Most commercial hosting providers and some public ones allow this)
FIREPASS' key feature is that you can chain several installations of the server and they never need to bind to a port; therefore, it is undetectable by most Administrators. There is only an unusual HTTP dialog between the client and server ; aswell, the HTTP messages are send fairly often.

But this is configurable in the FIREPASS client with a special delay option between HTTP requests, and can be used for any non-time-critical protocols.