When you talk about ECS being optional, you also have to keep the context in mind. * Yes, if you're running a local resolver for your LAN, or have a website on

When you talk about ECS being optional, you also have to keep the context in mind. * Yes, if you're running a local resolver for your LAN, or have a website on a single server, of course ECS should be optional. * If you're running a CDN (and archive.today does), or if you're running a public resolver at 100+ POPs, then, no, ECS is not meant to be optional.