I was wondering what this actually does. ISPConfig --> System --> Main Config --> Mail (Tab) --> down the bottom of the page "Use SSL/TLS encrypted connection for SMTP:" (Options: No SSL STARTTLS) The (very old) manual I have says very little about it other then stating it's used for encrypted connections to the SMTP server. But, what does it actually do? Does this mean that every time it sends an email to another mail server in the world it uses SSL/TLS encryption? Does this mean if the other end doesn't support that, the mail fails? Actually if I knew exactly what it changed in the postfix config files it might help. Obviously not going to test it on a live server. Servers: Debian and Ubuntu, postfix mail server.
Thanks for your reply. I looked at the page again and wondered if it was just referring to the fields above, where it asks for information about sending out system emails from ISPConfig. Either way I was, and still am, confused due to the way it's worded and shown. As to TLS for postfix, I don't think ISPConfig enables this by default. For mine I have "smtp_tls_security_level = may" in both main.cf and master.cf with the smtp_tls_cert_file and smtp_tls_key_file pointing to the applicable server certs. Using "may" means the server offers it but doesn't actually require it.
Which is usually what you want. Quickly check the source regarding the question. The option "Use SSL/TLS encrypted connection for SMTP" only affects how mails are send from ISPConfig itself. So you can set an SMTP Server and set some options on how ISPConfig connects to that SMTP Server to send out Systemmail instead of using the mail() PHP function. So this has nothing to do with the Postfix settings.
