Pacemaker is a dynamic rate-limiting script that watches network traffic and determines which machines are probably abusing your network. Pacemaker catches things like Windows worm scans, port scans, P2P network traffic, and anything else that tries to go beyond the normal number of connections a standard machine should use. The machine needs to abuse the network for two minutes before pacemaker will mark the IP address to be rate-limited. A machine will stay marked for as many minutes as it has abused the network.