There are also pam modules that can dynamically block repeated failed ssh login attempts. Pam_shield, for example defaults to blocking by null routing the ip,

There are also pam modules that can dynamically block repeated failed ssh login attempts. Pam_shield, for example defaults to blocking by null routing the ip, but you can drop in whatever action you want. There are other similar pam modules as well. I like a pam based approach since it isn't trolling log files, but directly controlling the auth.