This tip explains the process of setting up CentOS to allow VPN connections from the built-in windows vpn client. Authentication is handled through Active Directory.

I wrote this tip in response to a thread on a forum I sometimes visit. The tip is about 3/4 of the way down the page.

http://www.dslreports.com/forum/r22421964-VPN-Server

I also mirrored the page here:

http://www.computerglitch.net/other/VPN-Server.htm