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  1. Commons Email
  2. EMAIL-105

Clarify names for SSL and TLS



    • Type: Improvement
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 1.3
    • Labels:


      The API offers two categories of settings for the configuration of SSL/TLS: setSSL and setTLS (and respective associated methods).

      The names are quite misleading, as this doesn't really oppose SSL and TLS. A number of e-mail applications make this mistake, but "TLS" is used here to mean "using STARTTLS" and "SSL" is used here to mean "SSL or TLS, upon connection".

      The difference is that:

      • With "SSL" (as incorrectly named here), the SMTP client connects to the SMTP server on a dedicated port and starts the SSL/TLS handshake upon connection. This is then followed by "normal" SMTP traffic on this SSL/TLS layer.
      • With "TLS" (as incorrectly named here), the SMTP client connects to the SMTP server on the same port as it would do for plain-text SMTP, exchanges a few SMTP commands, including STARTTLS (RFC 3207), and then starts an SSL/TLS handshake to upgrade to a secure channel.

      This is not so much a difference between SSL and TLS, but rather a difference regarding when the connection is turned into a secure one.
      The difference between SSLv3 and TLS 1.0 is mostly a version difference, where SSLv3 is the predecessor of TLS 1.0.
      You can have an TLS 1.0+ upon connection, using the "SSL" setting, without using STARTTLS (it's a version configuration up to the SSLEngine or SSLSocketFactory).
      Similarly, although it's not written in the specification, some servers seem to accept an SSLv3 handshake (instead of its successor version: TLS 1.0) after STARTTLS.

      I'd suggest deprecating setSSL and setTLS and replacing them with setOnConnectSSL and setStartTLS (or similar), respectively.


        1. ssl-starttls.patch
          8 kB
          Bruno Harbulot



            • Assignee:
              sgoeschl Siegfried Goeschl
              harbulot Bruno Harbulot
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