Windows® 8.1 allows a Microsoft or third party VPN client to automatically connect to the corporate network. From an end user perspective, access to corporate intranet resources works the same as when inside the corporate network.
If auto triggering is enabled for a VPN profile, a remote access connection is triggered whenever a specific corporate resource or application is accessed. If user credentials are cached within the VPN profile, the VPN connection will be automatically established without any user interaction.
For more information, check out
http://technet.microsoft.com/en-us/library/dn383580.aspx