Fail2ban
From DWIKI
Custom rules
assp.conf
failregex = \[Worker_.*\] <HOST> \[SMTP Error\] 535 5.7.8 Error: authentication failed: \[Worker_.*\] \[SSL-in\] \[TLS-out\] <HOST> \[SMTP Error\] 535 \[Worker_.*\] \[MessageLimit\] <HOST> \[Worker_.*\] <HOST> .* \[SMTP Error\] 554 5.7.1
FAQ
Error in FilterPyinotify callback: 'module' object has no attribute '_strptime_time'
Enabling sshd-ddos filter seems to trigger this