edit:DNS servers for Cloudflare, Quad9, Google and Level3 all cname cdn.polyfill.io to Cloudflare domains. I assume those are the alt endpoints that Cloudflare

edit:DNS servers for Cloudflare, Quad9, Google and Level3 all cname cdn.polyfill.io to Cloudflare domains. I assume those are the alt endpoints that Cloudflare setup in Feb. Lots of folks seem to be protected now. Cloudflare notice: https://blog.cloudflare.com/polyfill-io-now-available-on-cdnjs-reduce-your-supply-chain-risk https://blog.cloudflare.com/polyfill-io-now-available-on-cdn... Feb discussion: https://github.com/formatjs/formatjs/issues/4363 https://github.com/formatjs/formatjs/issues/4363 (edit:withdrawn) For my use cases, I made the local DNS servers authoritative for polyfill.io. Every subdomain gets a Server Failed error. Might work for pihole too.