Hi Folks. Good day. I hope you're doing good. I'm seeing my logs flooded with information like this: Code: Jan 21 14:48:22 myserver.domain postfix/smtpd: warning: hostname net6-ip229.linkbg.com does not resolve to address 126.96.36.199: Name or service not known Jan 21 14:48:22 myserver.domain postfix/smtpd: connect from unknown[188.8.131.52] Jan 21 14:48:23 myserver.domain postfix/smtpd: disconnect from unknown[184.108.40.206] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4 I've been trying a to tweak fail2ban postfix filter to capture and block these IPs, but I'm not successful so far (partially because I'm not familiar with how the fail2ban structure works. Can anyone shine some light and share what modification should I make in what files to block these type of traffic? Thanks a lot in advance.