I would like to create some tunnel software which should integrate into Windows by installing a network adapter. I can't find any good way to get started on this topic. Is it somehow possible to develop such an adpater in java?
These cisco solutions manage to create a tunnel by only allowing the browser to run some java app, so it must be possible.
Any ideas or pointers in the right direction are highly appreciated.
Look into the way OpenVPN works. It installs an adapter and creates a VPN Tunnel. It's Open Source and available for Windows, Linux, etc.
http://openvpn.net/index.php/open-source/downloads.html
Also look into TUN http://en.wikipedia.org/wiki/TUN/TAP