this document demonstrates how to establish a secure ipsec tunnel using preshared keys to join a private network inside a linksys cable/dsl vpn router and a microsoft windows 2000 or xp pc. you can find detailed information on configuring the microsoft windows 2000 server at the microsoft website:

    microsoft kb q252735 - how to configure ipsec tunneling in windows 2000 http://support.microsoft.com/support/kb/articles/q252/7/35.asp

    microsoft kb q257225 - basic ipsec troubleshooting in windows 2000 http://support.microsoft.com/support/kb/articles/q257/2/25.asp