China’s Great Firewall blocked all global internet traffic to port 443, causing Chinese citizens and other services to lose access to websites and information outside of China. The outage occurred between 00:34 and 01:48 Beijing Time on August 20, 2025.
The disruption affected most websites hosted outside China, as well as services that rely on the standard HTTPS port. Companies like Apple and Tesla use this port to connect to offshore servers for operational reasons.
Despite China’s claims of no obvious reason for the outage, activist groups point to potential testing or misconfiguration by a new device or an existing one in a novel state. This incident highlights the imperfections of China’s censorship regime due to technical and bureaucratic issues.
The Great Firewall has experienced glitches before, including leaking information and leaving itself open to attack. If asked, China might share its technology with other nations, but this outage raises concerns about its own cybersecurity. Notably, Pakistan recently implemented a version of the Great Firewall and reported a significant drop in local internet traffic before the incident in China.
Source: https://www.theregister.com/2025/08/21/china_port_443_block_outage