fastnetmon
fast DDoS analyzer with sflow/netflow/mirror support (community edition)FastNetMon is a very high performance distributed denial-of-service attack(DDoS attack) detector built on top of multiple packet capture engines:NetFlow, IPFIX, sFLOW.It can detect hosts in your networks sending or receiving large volumes ofpackets/bytes/flows per second. It can call an external script to notify you,switch off a server, or blackhole the client.