Is there a way to set up a linux based, preferably ubuntu, SSTP server?
I know there is a SSTP client available on sourceforge, but I can't find a server.
To be clear: I do NOT want openVPN, I want SSTP
Yes, there is a Linux (and Windows/Mac) based SSTP (and lot more) VPN Server. It is called SoftEther VPN (http://www.softether.org). Best of off, it is free. Granted, there are couple of limitations with the free version (for example, cannot use external authentication, client certificates etc.)
In general, it seems to work fine. It is easy to install, use and manage. Has decently good documentation. Has quite a few options. I used it on Ubuntu 13.04 release. It does serve my SSTP server requirements.