How does SSL use symmetric and asymmetric encryption? And how do I manage certificated for multiple sites on one host? [duplicate]

Answer 1

The case where the session key is independently computed by the client and server without the key ever being transmitted is Diffie-Hellman key exchange: https://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exchange --- see the nice paint illustration PKI will exchange the encrypted session key between the client and server.