The techniques described in this disclosure provide resilient and reactive on-demand Distributed Denial-of-Service (DDoS) mitigation services using an exchange. For example, an exchange comprises a first virtual network for switching mixed traffic (including dirty (DDoS) traffic and clean (non-DDoS) traffic)) from one or more networks to one or more DDoS scrubbing centers; and a second virtual network for switching the clean traffic from the one or more DDoS scrubbing centers to the one or more networks, wherein the exchange is configured to receive the mixed traffic from the one or more networks and switch, using the first virtual network, the mixed traffic to a selected DDoS scrubbing center of the one or more DDoS scrubbing centers, and wherein the exchange is configured to receive the clean traffic from the selected DDoS scrubbing center and switch, using the second virtual network, the clean traffic to the one or more networks.