title: What do the SMTP Indy component security and authentication properties do?
body: <p>I am using the indy components to implement emails in a delphi application.  I am specifically using the TidSMTP component.   I need to effectively support all major email servers.  I use Mozilla Thunderbird as my email client and am comparing the smtp properties with those in the TidSMTP component.  I have attempted to find documentation that describes the relationship between the TidSMTP properties, but have not been able to figure it out.</p>
  
  <p>Can someone explain how these compare and what they do:</p>
  
  <ul>
  <li>In Thunderbird:Connection Security: (None, STARTTLS, SSL/TLS).</li>
  <li><p>In TidSMTP.UseTLS (utNoTLSSupport, utUseImplicitTLS, utUseRequireTLS, utUseExplicitTLS)</p></li>
  <li><p>In Thunderbird:Authentication method: (No Authentication, Normal Password, Encrypted Password, Kerberos/GSSAPI, NTLM)</p></li>
  <li>In TidSMTP (username, password, with useAuthentication method)</li>
  </ul>
  
  <p>I also see other TidSMTP properties: UseEhlo, UseVerp, UseNagle.  Do I need to be using these?  What do they do?</p>