Going through my logs yesterday, I see that one computer is repeatedly trying to log on via ssh. Over and over and over again with various guessed logins. Is there any way that you guys know of to just have ssh deny an IP address?
Maybe this link will give you some more info http://lists.debian.org/debian-user/2004/12/msg00375.html There are two packages of software, debian and portsentry that could be helpful as far my knowledge reaches.
You could use something like the following in your /etc/hosts.allow sshd: 172.17.12.0/255.255.255.0 should you need to access from another location simply add that on another line. and then in your /etc/hosts.deny put ALL:ALL If your using IP tables you can ban an IP range along with most other firewall applications.