mod_tunnel is a simple Apache module that can be used to create TCP tunnels using your Web server. It is useful to expose services which can be reached through a proxy, bypassing firewalls.

After only 4 years since the previous version, you can now download version 2.0 which works with Apache 2.2.x (and maybe 2.0.x, but I haven’t tested it).

You’ll find it on sourceforge.