title: Does System.Net.Mail.SmtpClient use SSL, TLS, StartTLS, or a combination?
body: <p>This question has answers about negotiating the best version of TLS/SSL available with the server: <a href="https://stackoverflow.com/questions/26414424/which-versions-of-ssl-tls-does-system-net-webrequest-support">Which versions of SSL/TLS does System.Net.WebRequest support?</a></p>
  
  <p>However I thought SmtpClient used regular Smtp for transport, with TLS on top - which as I understand it is StartTLS.</p>
  
  <p>I am documenting some software (a box ticking exercise) and need to state which protocols are used, and security protocols are really not my area of expertise so how can I explain this well?</p>