Hi, Perdition has the option "ssl_mode" which can be used to set both listening and outgoing connections. Its made up of options that are prefixed either by 'ssl' or 'tls'. From my experimentation, it seems as if the 'tls' options aren't actually TLS, but rather the STARTTLS extension for IMAP and POP. So what is the difference? The difference is that an actual TLS connection would be one whereby the client and server negotiate a stateful connection by using a handshaking procedure where they agree on various parameters that will be used to establish the connection's security. This is all done during the bring up of the connection, and the client wont send a login/password until the connection has been properly setup. STARTTLS, by contrast, proceeds by the client making a clear-text connection to the server, noting that the server has the STARTTLS capability (to use the IMAP terminology), requests that a STARTTLS negotiation process begins and then you promote up to an actual TLS connection. After you've promoted, then your connection is encrypted. Why is the distinction important? With STARTTLS the potential for credential leak exists during the clear-text window. Perdition offers the tls_listen_force/tls_outgoing_force/tls_all_force settings to 'ssl_mode', but all this does in IMAP4/IMAP4S is have the LOGINDISABLED set, which doesn't stop a client from attempting to login, it just refuses their login after they've sent it over the clear-text connection. As the RFC (2595) referenced in the man page states: Servers advertising this capability will fail to interoperate with many existing compliant IMAP clients and will be unable to prevent those clients from disclosing the user's password. I think that the option 'ssl_mode' is a confusing name. TLS and SSL are different things (although many people still call TLS connections SSL). Additionally the use of the name 'tls' in the potential options is confusing, when the actual behavior is STARTTLS. It seems to me that the existing 'tls' options should be renamed 'starttls_*' and an actual TLS option be added. I also notice that the man page says, "TLS is defined in RFC 2595". This isn't really correct, again its STARTTLS that is defined in RFC 2595. This RFC, although titled this way in 1999, is known as the canonical reference defining STARTTLS for IMAP and POP3 (there are others for things like SMTP). TLS, on the other hand, is actually detailed in RFC 5246.