MISP and fail2ban
fail2ban - MISP
fail2ban is known to do a great job at giving attackers a hard time when they try to “test” passwords or enumerate users of a service. fail2ban constantly analyses relevant log files and keeps track of IP addresses trying to log into such services. If a configurable threshold is reached, it uses the Linux firewall (Netfilter / iptables) to block the suspected attackers.