You cannot establish an IPsec connection between a Linux operating system and a Windows Vista operating system when you initiate the connection from the Linux operating system
Consider the following scenario. You use Windows Vista Local Security Policy on a Windows Vista-based computer. Or, you use the new Windows Firewall with Advanced Security on a Windows Vista-based computer. You try to initiate an Internet Protocol Security (IPsec) connection from a Linux-based computer to the Windows Vista-based computer. In this scenario, you cannot establish the connection.
- If you initiate the IPsec connection from the Windows Vista side, the connection is established correctly.
- Windows XP and Windows Server 2003 work correctly with the Linux operating system in this environment.
For more information on this issue, including potential causes, workarounds, and resolutions, see: Microsoft KB Article KB950826.