1. A network system for dynamic routing of internet protocol traffic, the network system comprising: an on-demand application service controller configured to receive an on-demand service request for an application service, wherein the application service comprises a distributed denial of service mitigation service and the on-demand service request is received in response to a distributed denial of service attack, generate a validation request in response to receiving the on-demand service request, the validation request being used to validate a customer that provided the on-demand service request is responsible for a site for which the application service has been requested, generate a diversion routing control message in response to receiving the on-demand service request for the application service, the diversion routing control message comprising instructions for an ingress provider edge router to divert ingress traffic from an intended destination to a distributed denial of service attack scrubber, implemented by an application server, for processing, generate a re-injection routing control message in response to receiving the on-demand service request for the application service, the re-injection routing control message comprising instructions for an application service provider edge router to deliver the ingress traffic processed by the distributed denial of service attack scrubber to the intended destination, send the diversion routing control message to the ingress provider edge router, and send the re-injection routing control message to the application service provider edge router; the ingress provider edge router being configured to receive the diversion routing control message from the on-demand application service controller, receive the ingress traffic directed to the intended destination, and redirect the ingress traffic in accordance with the diversion routing control message to the application service provider edge router; and the application service provider edge router being configured to route the ingress traffic to the distributed denial of service attack scrubber implemented by the application server.