I'm using openssl to connect to an SMTP server normally (without encryption), send a STARTTLS command, negotiate the SSL encryption, and then interact with the encrypted session. This is the command I'm using (through telnet): openssl s_client -starttls smtp -crlf -connect 1.2.3.4:25 How can I ensure that TLS handshake was successful? This is the sequence of commands used so far: << 220 example.co