SSTP, or Secure Socket Tunneling Protocol, is designed to safeguard PPP traffic using the SSL/TLS channel. It's a much better and safer for Windows users as opposed to L2TP/IPSec or PPTP. It's difficult to block and offers good speeds only if you have adequate bandwidth.
Secure Socket Tunneling Protocol (SSTP) is a secure protocol used in VPN tunneling. The protocol, though owned by Microsoft, is available to both Linux and Mac users. SSTP uses SSL/TLS (Secure Socket Layer/Transport Layer Security) channel over TCP 443 port.
A client’s system connects to a server through a TCP (Transmission Control Port). SSL uses the 443 port to connect to the server. To confirm the connection, it requires user authentication. And, it is usually authenticated by the client. The protocol uses the server certificate for authentication.
There are many reasons that endorse the popularity of SSTP. For instance, SSTP offers the highest level of security, i.e., 256-bit AES encryption. Moreover, the port it uses can circumvent almost all types of firewalls. Since it is a Microsoft owned property, it is completely compatible with Windows.
SSL and SSTP connections use same port i.e. port 443.
SSTP uses the same mechanism of data transmission as SSL does.
The encryption bit used by SSTP is 2048.