Undesirable behavior patterns of computers on a network impact network performance. A system and method are provided for limiting the impact of undesirable behavior of computers on the network. The network, through which packets of data are interchanged between the computers, includes one or more forwarding devices that are controlled or instructed by one or more packet traffic monitors. Each of the packet traffic monitors is configured for monitoring the packets; for determining if the information about the pattern of behavior from any of the computers is trustworthy; for determining, upon discovering that one or more of the patterns of behavior is undesirable, a type of the undesirable pattern behavior; and for determining a proper action for mitigating that type of undesirable behavior. The proper action is performed by mitigation means controlling the one or more forwarding devices.