hello! so I as well have problems with smtp using postfix - but only when I try to send emails using thunderbird. I've used the how to on virtual users (postfix, courier, mysql) a while back and just upgraded from postfix version 2.9.3 to 2.9.6. netstat tells me, that (some process) is listening on 0.0.0.0:25, and using telnet on port 25 gives me a 250 return on starttls. using squirrelmail and my android mail app (k9) everything worked fine. and my thunderbird configs are: mail.serverdomain.tld - port 25 - starttls I realize that this may well be a thunderbird specific problem, but since I am fairly sure that this problem came once I updated. thanks!