title: Is there a way I can tell whether an SMTP server is expecting a client to connect using "implicit" SSL versus "explicit" SSL?
body: <p>SSL can either be "explicit" or "implicit" as explained by this link:</p>
  
  <p><a href="http://help.globalscape.com/help/secureserver2/Explicit_versus_implicit_SS.htm" rel="nofollow noreferrer">http://help.globalscape.com/help/secureserver2/Explicit_versus_implicit_SS.htm</a></p>
  
  <p>System.Net.Mail only support "explicit" SSL, as explained here:</p>
  
  <p><a href="http://blogs.msdn.com/webdav_101/archive/2008/06/02/system-net-mail-with-ssl-to-authenticate-against-port-465.aspx" rel="nofollow noreferrer">http://blogs.msdn.com/webdav_101/archive/2008/06/02/system-net-mail-with-ssl-to-authenticate-against-port-465.aspx</a></p>
  
  <p>So, I'm trying to use System.Net.Mail to connect to an SMTP server that I don't have any control over, and it's failing.  How can I know for sure that it's failing because the server wants an "implicit" SSL connection?   What test can I do from the client side?</p>