• UDP DDoS Attacks are DDoS attacks deploying the UDP protocol (User Datagram Protocol), and rely on the fact that for every erroneous UDP packet sent to a given resource, an ICMP Destination Unreachable packet needs to be returned, serving as an “Error, Return to Sender” message. Flooding the targeted site with incoming UDP packets results in a counter-flood of outgoing ICMP Destination Unreachable packets, which ultimately renders the site unavailable to legitimate users.