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Introduction

Let`s take a look at the SSTP connection mechanism:

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1. A TCP connection is established from client to server (by default on port 443);
2. SSL validates the server certificate. If a certificate is valid, a connection is established otherwise the connection is turned down. (But see note below);
3. The client sends SSTP control packets within the HTTPS session which establishes the SSTP state machine on both sides;
4. PPP negotiation over SSTP. The client authenticates to the server and binds IP addresses to the SSTP interface;

SSTP tunnel is now established and packet encapsulation can begin;

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