This technique, uses iptables to block a particular IP, that has passed the threshold of a certain number of connections in a given period of time.
Ubuntu 7.10 actually comes with some pretty good security practices already set up for you. For example, the root account is locked and no network services are enabled by default. If you’re planning on making your Ubuntu system publicly accessible, here are some things to consider before you forward a port or public IP address.
SSH is a great way to remotely administer a server. However, it still has a number of issues when you open it up to the world. The server and client communications are secure but that doesn’t mean the hosts involved are. Opening an SSH service to the world allows for brute force attacks and means that the carbon interface is still the weakest link.