pptp is an implementation of the PPTP protocol for Linux and other Unix systems. The code is released under the terms of the GPL; see the file COPYING for details. You can find notes on installing in the file INSTALL, usage notes in the file USING, design notes in the Documentation directory, and the standards documents used to implement pptp can be found in the Reference directory. New versions and additional documentation can be found on the PPTP Client project page, at http://pptpclient.sourceforge.net/