Abstract: A communication network is operated by detecting an anomaly in the communication traffic at a plurality of nodes in a communication network. A first blocking measure A is independently applied at respective ones of the plurality of nodes to the anomalous traffic that stops the anomalous traffic. A second blocking measure B is independently determined at the respective ones of the plurality of nodes such that application of a logical combination of the first blocking measure A and the second blocking measure B to the anomalous traffic stops the anomalous traffic.

Abstract: A detection and response system that generates an Alert if unauthorized scanning is detected on a computer network that includes a look-up table to record state value corresponding to the sequence in which SYN, SYN/ACK and RST packets are observed. A set of algorithms executed on a processing engine adjusts the state value in response to observing the packets. When the state value reaches a predetermined value indicating that all three packets have been seen, the algorithm generates an Alert.