A Comprehensive Guide to PPTP, L2TP, and Other VPN Protocols
What is SSTP?
SSTP stands for Secure Socket Tunneling Protocol. Unlike the other protocols, SSTP is owned directly by Microsoft and is available for Windows only.
SSTP is so named because it transports traffic through the SSL (Secure Sockets Layer) protocol. Because it uses SSL over TCP port 443 it is much less susceptible to blocking by firewalls than L2TP.
Although it doesn't share the same open source advantages as OpenVPN, SSTP is generally considered to be one of the most secure protocols.
Natively supported on Windows
Only available on Windows