Isn't a flood attack more likely? I would look into the rate limiting. I used a script to flood the server and the limiting does kick in.
I also tried dumping random text at the mail port and it eventually makes some funny comment then stops listening. There doesn't seem to be much mail server pentest programming available. Original Message From: Lefteris Tsintjelis Sent: Saturday, July 9, 2016 8:07 AM To: postfix-users@postfix.org Subject: Brutal attacks Is this a good postfix way to stall attackers (besides log parsing and fire walling)? Bots are increasing dramatically these days smtpd_soft_error_limit = 1 smtpd_hard_error_limit = 1 smtpd_error_sleep_time = 16s (or even more)
