READ THIS IMPORTANT SECTION !!!
I hereby disclaim all responsibility for your use of this hack. If it backfires on you in any way whatsoever, that's the breaks. Not my fault. If you don't understand the risks inherent in doing this, don't do it. If you use this hack and it allows vicious vandals to break into your company's computers and costs you your job and your company millions of dollars, well that's just tough nuggies. Don't come crying to me.
Copyright © 1998-2001 by François-René Rideau.
This document is free software published under the bugroff license.
I haven't been actively developing this mini-HOWTO recently; in particular, the french version is lagging behind. I'm looking for a maintainer to take over this document, and maybe develop software to make it easier to pierce firewalls. I also have a lot of ideas for active maintainers to expand this HOWTO, if anyone is interested.
Even though the only thing left is the disclaimers, this document owes a lot to the Term-Firewall mini-HOWTO by Barak Pearlmutter. Barak's mini-HOWTO relies on an ancient and no-more-supported program named Term (a great program in its time, and maybe still useful in some unhappy circumstances), as well as on peculiarities of a not-so-standard telnet implementation, that is, many obsolete and non-portable facts. Nevertheless, there was a necessity for a mini-HOWTO about piercing firewalls, and despite the limitations of its hacks, this mini-HOWTO was a model and an encouragement.
I'd also like to congratulate Lars Brinkhoff and Magnus Lundström for their fine http, mail and icmp tunnels.