After nmap-ing my on of my servers, I found some ugly IPs trying to bruteforce my SSH accounts.
After writing a script for my SSH deamon which logs bad IPs and add them to hosts.deny, I thought about all the other deamons on my server.

Not willing to write fancy scripts for all the others, I installed the nice tool fail2ban which add bad IPs to a local banlist.
It works like a charm and the best of all: There is a nice frontend call bad IPs.
A nice visualization for every server owner 😉