OpenVPN is a SSL based, cross platform VPN package that I recently downloaded and installed on my network. I am very impressed with it. It works equally well Linux to Linux, Linux to Windows, Windows to Linux, and Windows to Windows. Two basic configurations exist. The VPN connection can be setup to bridge the client onto the remote network or the VPN can be configured as a simple route based connection. For various reasons, I avoided the bridge and went with the routable connection. The configuration is straight-forward and except for a issue that I had with my firewall on my Linux box, it worked almost out-of-the-box.
I have configured my Windows XP laptop to connect to my Linux server and I am able to, using a basic NAT firewall configuration on my Linux server, redirect all my traffic from my laptop through my Linux server and out to the world.
Linux Journal has a good writeup on OpenVPN along with some basic configuration notes. [/url]http://www.linuxjournal.com/node/7949/print
The main web page for OpenVPN is at http://openvpn.sourceforge.net/
I would be interested in hearing from everyone on their thoughts on the package. Especially if you have any configuration tricks and/or handy suggestions.
P38
My configuration files follow:
#On the linux server:
dev tun
proto udp
ifconfig 10.0.0.2 10.0.0.1
secret key.txt
ping 10
verb 3
mute 10
#On the XP laptop:
ip-win32 manual
remote 12.47.129.150
dev tun
proto udp
ifconfig 10.0.0.1 10.0.0.2
secret key.txt
redirect-gateway
verb 3
ping 10
mute 3
ping-restart 120
Note: While testing, you probably want to turn off the "redirect-gateway" option on the client machine. This option will remove your existing gateway and replace it with one that directs all traffic out the vpn connection. If you are not prepared for it, it can cause you problems with several things especially DNS. When the connection is dropped or you take it down, the gateway setting is set back to its previous values.
You also have a new network connection that is created during the install process on the XP box. The "ip-win32 manual" tells the OpenVPN software that you have set static values in the network connection settings.
Other links:
OpenVPN win32 GUI tool: http://www.nilings.se/openvpn/index.html
OpenVPN and the SSL VPN Revolution: http://www.sans.org/rr/whitepapers/vpns/1459.php
OpenVPN HOWTO: [url=http://openvpn.sourceforge.net/howto.html]http://openvpn.sourceforge.net/howto.html