Webtunnel
Webtunnel is a network utility that encapsulates arbitrary data in HTTP and transmits it through a web server. In that regard, it is similar to httptunnel, however, it has several key important differences: its server component runs in the context of a web server as a CGI application (with optional FastCGI support) so it does not need its own port, and supports most things that the web server supports, such as authentication, HTTP 1.1, HTTPS, and client certificates; it uses simple requests and responses so it works seamlessly through forward and reverse proxies; it is multi-threaded (actually multi-process using sockets for inter-process communication) to allow multiple parallel connections to multiple destinations simultaneously.
History
I was planning on using "httptunnel" to be able to access my home network from locations where only web access was available, but it didn't seem to work through a reverse proxy. Additionally, it allowed only one connection at a time and required multiple instances to tunnel to different ports. So instead of dealing with the limitations, I started this project to create a web server based replacement.