In one kind of DoS attack, malicious customers may try to send a large number of filter requests against an innocent customer. In one implementation, a Filter Request Server (FRS) may allow a customer against who a filter request is made to dispute the implicit accusation of the filter request or stop sending malicious traffic. If the customer claims innocence, the FRS may log destination addresses of data packets sent by the customer and identify and ignore false filter requests if these filter requests come from customers who do not correspond to one or more of the destination addresses that have previously been logged by the FRS.