How to Recover a Domain Blocked by DNS Poisoning: Layered Diagnosis Before Cleaning or Reverse Proxy

A domain suddenly inaccessible in mainland China may not be DNS poisoning — this article provides a four-step check to confirm resolution-layer spoofing, rules out more common causes, and presents two recovery paths: temporary client-side self-rescue (DoH/DoT, hosts) and business-side recovery without changing the domain (poisoning cleaning, reverse proxy/high-defense CDN), plus post-recovery validation and recurrence monitoring.