Great Firewall Anomaly: Widespread TCP Port 443 Outage in China
2025-08-20
Between 00:34 and 01:48 Beijing Time (UTC+8) on August 20, 2025, the Great Firewall of China (GFW) exhibited anomalous behavior, unconditionally injecting forged TCP RST+ACK packets to TCP port 443, causing a massive disruption of internet connections between China and the rest of the world. The roughly 74-minute outage affected only port 443, with asymmetrical triggering mechanisms for inbound and outbound traffic. Analysis suggests the responsible device doesn't match known GFW fingerprints, possibly indicating a new device or a misconfigured one. Researchers urge community participation to fully understand this event.
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