TGC is the TCP Gender Changer.

Copyright (C) 2008-2014 Faraz V (faraz@fzv.ca)

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

Disclaimer:
This program is provided with no warranty of any kind, either expressed or
implied.  It is the responsibility of the user (you) to fully research and
comprehend the usage of this program.  As with any tool, it can be misused,
either intentionally or unintentionally.
THE AUTHOR(S) IS(ARE) NOT RESPONSIBLE FOR ANYTHING YOU DO WITH THIS PROGRAM
or anything that happens because of your use (or misuse) of this program.


THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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SUCH DAMAGE.



You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.


* Technical details:

	tgcd is a simple Unix network utility to extend the accessibility of TCP/IP based network services
	beyond firewalls.
	This can also be used by network analysts and security experts for penetration testing and analyze 
	the security of their network.

	This program has 3 different modes:

	- CC (ConnectConnect)
	- LL (ListenListen)
	- PF (PortForwarder)

	CC and LL nodes are used together to provide access to a service inside a Local 
	Area Network to the external network. PF node is, however, only a simple
	port forwarder.

	CC node resides in the LAN and connect to the LL (on the external network), and
	once a client connects to LL, then CC gets notified and establishes a connection
	to the server on the LAN.

	This program complies with host_access (aka libwrap), to control its accessibility.

	The idea is nothing new and there has been many implementation of it available already, 
	namely:

 	- revinetd (written by Steven M. Gill and Alexandre Carmel-Veilleux)
		available at: http://revinetd.sourceforge.net

	- An implementation using "socat" (an excellent network utility):
		http://www.dest-unreach.org/socat/doc/socat-gender.txt

	- FireWall Tunnel, available at: http://sourceforge.net/projects/firewall-tunnel/

	- An artile explaining the idea: 
		http://www.bandwidthco.com/whitepapers/netforensics/tcpip/TCP-IP%20Gender%20Changer.pdf

	There might be other implementations using netcat or other network utilities.


	For more information and examples on how to use this utility please refer to its
	man page (tgcd(1)).
	
	This software is provided only as a tool for network security analysts and
	penetration testers. We do not take any responsibility for any damage that
	can be done by using or misusing this software. Use it responsibilly and 
	at your own risk (read the disclaimer above)


	NOTE:  This software has only been tested on the following platforms:

	Linux 2.2.x (x86), 2.4.x (x86), 2.6.x (x86, ARM9, AVR32), Cygwin (1.5.x), NetBSD 2.1.0

	Please feel free to send us your comments or any patches you may have to get tgc 
	working on other platforms.