Network Security Hacks

Tunnel Connections Inside HTTP

Break through draconian firewalls by using httptunnel.

If you’ve ever been on the road and found yourself in a place where the only connectivity to the outside world is through an incredibly restrictive firewall, you probably know the pain of trying to do anything other than sending and receiving email or basic web browsing.

Here’s where httptunnel (http://www.nocrew.org/software/httptunnel.html) comes to the rescue. Httptunnel is a program that allows you to tunnel arbitrary connections through the HTTP protocol to a remote host. This is especially useful in situations like the one mentioned earlier, when web access is allowed but all other services are denied. Of course, you could just use any kind of tunneling software and configure it to use port 80, but where would that leave you if the firewall is actually a web proxy? This is roughly the same as an application-layer firewall, and will accept only valid HTTP requests. Fortunately, httptunnel can deal with these as well.

To compile httptunnel, download the tarball and run configure and make:

$ tar xfz httptunnel-3.3.tar.gz 
$ cd httptunnel-3.3
$ ./configure && make

Install it by running make install, which will install everything under /usr/local. If you want to install it somewhere else, you can use the standard --prefix= option to the configure script.

The httptunnel client program is called htc, and the server is hts. As with ssh [Hack #76] , httptunnel can be used to listen on a local TCP port ...