denyhosts | a utility to help sys admins thwart SSH crackers | Mehr ...
DenyHosts is a program that automatically blocks SSH brute-force attacks by adding entries to /etc/hosts.deny. It will also inform Linux administrators about offending hosts, attacked users and suspicious logins. . Synchronization with a central server is possible too. . Differently from other software that do same work, denyhosts doesn't need support for packet filtering or any other kind of firewall in your kernel.
