2. Blurb This is the Linux VPN howto, a collection of information on how to set up a Virtual Protected Network in Linux (and other unices in general). 2.1 Copyright This document is part of the Linux HOWTO project. The copyright notice is the following: Unless otherwise stated, Linux HOWTO documents are copyrighted by their respective authors. Linux HOWTO documents may be reproduced and distributed in whole or in part, in any medium physical or electronic, as long as this copyright notice is retained on all copies. Commercial redistribution is allowed and encouraged; however, the author would like to be notified of any such distributions. All translations, derivative works, or aggregate works incorporating any Linux HOWTO documents must be covered under this copyright notice. That is, you may not produce a derivative work from a HOWTO and impose additional restrictions on its distribution. Exceptions to these rules may be granted under certain conditions; please contact the Linux HOWTO coordinator at the address given below. In short, we wish to promote dissemination of this information through as many channels as possible. However, we do wish to retain copyright on the HOWTO documents, and would like to be notified of any plans to redistribute the HOWTOs. If you have questions, please contact Tim Bynum, the Linux HOWTO coordinator, at linux-howto@sunsite.unc.edu via email. 2.2 Disclaimer As usual: the author not responsible for any damage. For the correct wording, see the relevant part of the GNU GPL 0.1.1 2.3 Disclaimer We are dealing with security: you are not safe if you haven't got good security policy, and other rather boring things. 2.4 Credits Thanks to all of who has written the tools used. Thanks to Zot O'Connor <zot@crl.com> for pointing out the "no controlling tty" problem, and it's solution. 2.5 State of this document This is very preliminary. You should have thorough knowledge of administrating IP, at least some knowledge of firewalls, ppp and ssh. You should know them anyway if you want to set up a VPN. I just decided to write down my experiences not to forget them. There are possibly some security holes indeed. To be fair I've tried it on hosts configured as routers not firewalls, saying: It's simple from that point. 2.6 Related documentations The Linux Firewall-HOWTO /usr/doc/HOWTO/Firewall-HOWTO The Linux PPP-HOWTO /usr/doc/HOWTO/PPP-HOWTO.gz The ssh documentations /usr/doc/ssh/* The Linux Network Admins' Guide NIST Computer Security Special Publications http://csrc.ncsl.nist.gov/nistpubs/ Firewall list (majordomo@greatcircle.com)