Red Hat Bugzilla – Bug 1475231
Support opportunistic STARTTLS for the incoming connections by default
Last modified: 2017-07-26 05:04:44 EDT
+++ This bug was initially created as a clone of Bug #1282350 +++
Currently the postfix server if installed by default does not support opportunistic STARTTLS for the incoming connections. It would be nice if a selfsigned certificate was generated as part of the installation or during the first startup of postfix similarly to what is done when mod_ssl is installed and the default configuration of postfix included 'smtpd_tls_security_level = may' setting so that opportunistic encryption of all mail transfer is enabled.
Although the self-signed certificate is not too useful for serving https web pages, it actually is much more useful in case of opportunistic encryption for SMTP. It does not prevent MITM attacks but in case of SMTP the attacker capable of doing MITM on the client side could probably also spoof DNS MX records and do MITM in much simpler way than to attack the actual connection. On the other hand the opportunistic encryption prevents mass-scale passive eavesdropping of the transferred e-mails and that is an useful goal to achieve by itself.
--- Additional comment from Tomas Mraz on 2015-11-16 09:40:39 CET ---
And actually the opportunistic encryption of outgoing connections should be enabled by default too by setting 'smtp_tls_security_level = may'.