My email server is attempting to send out a great deal of spam. I'm using Postfix & Dovecot.
I'm trying to diagnose the problem and figure out how this is being sent. My guess right now is that it's using an insecure port 25 to send the email. Does this seem consistent with the logs? How can I fix this?
Dec 29 01:29:22 balloonindustries postfix/smtpd[25536]: connect from m69-77.mailgun.net[166.78.69.77]
Dec 29 01:29:22 balloonindustries postfix/smtpd[25536]: SSL_accept error from m69-77.mailgun.net[166.78.69.77]: 0
Dec 29 …