A recent internet disruption appears to have been a digital readiness drill ahead of an upcoming military parade, say experts.
China briefly blocked nearly all encrypted internet traffic in the early hours of Aug. 20, in what cybersecurity researchers and engineers believe was a large-scale test of an upgraded version of the country’s internet censorship system, known as the Great Firewall.
From 12:34 a.m. to 1:48 a.m. Beijing time on Aug. 20, China’s internet filtering system injected forged reset signals into all connections using TCP port 443—the standard port for HTTPS traffic. It caused widespread connectivity failures between users in China and overseas websites, according to a technical analysis by the Great Firewall Report, a foreign research group that monitors Chinese internet censorship.
Around the same time, social media platforms in and out of China were flooded with user reports of internet disruptions, with many sharing screenshots showing failed attempts to connect to international websites and IP addresses.
The outage also left users unable to access virtual private networks (VPNs), which rely on encrypted connections to bypass China’s Great Firewall.
According to the Great Firewall Report, the interference appeared targeted and technically sophisticated. The equipment used for the injections did not match the fingerprints of China’s known censorship infrastructure, suggesting the deployment of new devices or updated configurations.
“This looked like a readiness drill after a major firewall upgrade,” said a network engineer in Hebei province who observed the outage told the Epoch Times, speaking on the condition of anonymity for fear or retaliation. “It happened during low-traffic hours and lasted just long enough to probe vulnerabilities before patching them.”
He added that similar tests had occurred before based on his observation, but they cannot be compared with the scale and duration of the Aug. 20 incident. For example, he recalled a similar event that occurred about a month earlier and lasted approximately 20 minutes around 1 a.m.
Another network engineer in China, also speaking on the condition of anonymity, similarly said the incident resembled a cyber drill.
“In the event of mass unrest, authorities need to be able to pull the plug on external communications instantly,” he said.
He told the Chinese-language edition of The Epoch Times that the growing decentralization of China’s censorship architecture is another aspect of the intensification of internet control. In addition to national-level controls, several provinces, such as Henan and Shandong, have begun implementing their own regional firewalls to filter traffic independently.
By Olivia Li
