This document relates to a CDN balancing mitigation system. An implementing CDN can deploy systems and techniques to monitor the domains of content provider customers with an active DNS scanner and detect which are using other CDNs on the same domain. This information can be used as an input signal for identifying and implementing adjustments to CDN configuration. Both automated and semi-automated adjustments are possible. The system can issue configuration adjustments or recommendations to the implementing CDN's servers or to its personnel. These might include “above-SLA” treatments intended to divert traffic to the implementing CDN. The effectiveness can be measured with the multi-CDN balance subsequently observed. The scanning and adjustment workflow can be permanent, temporary, or cycled. Treatments may include a variety of things, such as more cache storage, routing to less loaded servers, and so forth.