[4] [MS-SSTP]: Secure Socket Tunneling Protocol (SSTP) (2017-09-06 21:22:24 +09:00) <https://webcache.googleusercontent.com/search?q=cache:Jkzip1J7k6oJ:https://winprotocoldoc.blob.core.windows.net/productionwindowsarchives/MS-SSTP/%5BMS-SSTP%5D.pdf>