Postfix has a similar note: > NOTE: By turning on TLS support in Postfix, you not only get the ability to encrypt mail and to authenticate remote SMTP clients

Postfix has a similar note: > NOTE: By turning on TLS support in Postfix, you not only get the ability to encrypt mail and to authenticate remote SMTP clients or servers. You also turn on hundreds of thousands of lines of OpenSSL library code. Assuming that OpenSSL is written as carefully as Wietse's own code, every 1000 lines introduce one additional bug into Postfix. http://www.postfix.org/TLS_README.html http://www.postfix.org/TLS_README.html