Systems and methods are described that mitigate and/or prevent distributed denial-of-service (DDOS) attacks. In one implementation, a gateway include one or more processors that obtain network data from one or more entities associated with the gateway, provide the network data to a server, and obtain a set of entity identifiers from the server. The set of entity identifiers may be generated based on at least the network data. The one or more processors may further filter communications based on the set of entity identifiers.