I'm running a stack with Next.js, MongoDB Atlas, Cloudflare Images, and AWS Amplify. On my home internet connection, iPhones and iPads can't open cloudflare.com or any imagedelivery.net URL; they report that the server can't be reached. My own site loads, but images hosted through Cloudflare never appear.
The same iPhone works normally over cellular data. At my father's home, which uses the same ISP about 2 km away, iOS devices show the same failure while Android devices work. At a friend's location roughly 10 km away on that ISP, Cloudflare works on every device.
This seems specific to iOS and possibly to a particular ISP node or region. Could this be caused by a broken IPv6 route, since iOS may prefer IPv6 through Happy Eyeballs, or by localized DNS or BGP filtering? What's the best way to confirm the cause, and is this something the ISP would need to fix?
1 Answer
First check whether iCloud Private Relay or the Limit IP Address Tracking setting is enabled on the affected Wi-Fi networks. Disable it temporarily and test again. Those privacy features can change DNS and routing behavior, so they’re worth ruling out before assuming Cloudflare or the ISP is blocking the traffic.
How can I disable or test that setting? I want to compare the affected Wi-Fi connection with cellular data.