sshutout is a daemon that periodically monitors log files, looking for multiple failed login attempts via the Secure Shell daemon. The daemon is meant to mitigate what are commonly known as "dictionary attacks," i.e. scripted brute force attacks that use lists of user IDs and passwords to effect unauthorized intrusions. The sshutout daemon blunts such attacks by creating firewall rules to block individual offenders from accessing the system. These rules are created when an attack signature is detected, and after a configurable expiry interval has elapsed, the rules are deleted.
