I recently configured my server so that ssh logins will only work using public key encryption, and not plain old passwords. I noticed that lfd stopped detecting and banning IPs for people that attack ssh. Not a problem, you might think, since they will never get in anyway since they don't have a valid key. However, looking at the very long logfile of attempts, I thought it was probably best to lock them out anyway in case they might try other attacks, and just for neatness sake. I added the following to /etc/csf/regex.pm inside the processline sub, below the equivalent line looking for "Illegal user":