ECS

Is there documentation that explains how ECS is expected to work on Control D? The only page I can find is https://docs.controld.com/docs/disable-dnssec-option, but this does not explain how ECS is implemented. Generally, I would expect the source client subnet of my own IP address to be provided unless documented otherwise.

I was surprised to see that the client subnet is overwritten with an address associated with the specific DNS server location chosen by Anycast. I would expect this in Proxy mode but not Bypass mode.

Since the client subnet used is from the Control D location instead of my own, I have noticed decreased performance on some CDNs (notably Akamai and Cloudfront/AWS). By way of example, I am routed to the JFK location for Control D, but I am physcially closer and have lower latency to Ashburn/DC for most CDNs. It also looks like some services utilize ECS to support integrated CDNs within the ISP (e.g. Qwilt).

Is there any way to configure ECS to represent my actual subnet/location? For now, I am utilizing another DNS service for common CDN domains instead of Control D and seeing increased performance.

Thank you.