From http://www.nocrew.org/software/httptunnel.html:
"httptunnel creates a bidirectional virtual data connection tunnelled in HTTP requests. The HTTP requests can be sent via an HTTP proxy if so desired. This can be useful for users behind restrictive firewalls. If WWW access is allowed through a HTTP proxy, it's possible to use httptunnel and, say, telnet or PPP to connect to a computer outside the firewall."
Translation: As long as your proxy allows access to web pages, and you have access to both a machine inside the firewall as well as a machine outside the firewall capable of running httptunnel, you can run any one TCP/IP service through the firewall -- such as Apple Filing Protocol (iDisk, iTools, AppleTalk/AppleShare via TCP/IP), gnutella, Unreal Tournement server, etc. -- between the two machines.
Read the rest of this article if you'd like a step-by-step how-to on getting httptunnel working on OS X...
Skinlayers
[Editor's note: You'll need the Developer's Tools installed to compile the program.]
So far, httptunnel works on *NIX machines and Windows (both Win32 and WinNT). As an experiment, I was able to download and compile the source code. To do this:
hts -hat the Terminal will give you various server options. hts must be told:
hts -F 127.0.0.1:548 666This will forward all incoming HTTP requests on port 666 to port 548 on the machine hts is running on (note: 127.0.0.1 always means "this" computer).
htc -F 548 -P 10.0.0.1:8888 123.456.789.10:666Now the machine inside the firewall I would use the Finder's "Go -> Connect to Server..." menu item. For the server name I would enter 127.0.0.1 (since the machine inside the firewall is acting as the server redirecting to outside the firewall). Presto! You should now be able to move files both ways through the firewall transparently.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20010802202111922