China's Great Firewall cuts off external communications for over an hour
On August 20, 2025, China's internet censorship system,
Analysis of the GFW's Unconditional Port 443 Block on August 20, 2025
https://gfw.report/blog/gfw_unconditional_rst_20250820/en/
China's Great Firewall blocked all traffic to a common HTTPS port for over an hour, severing connection to the outside world — with no hint as to its intention | Tom's Hardware
According to the Great Firewall monitor site GFW Report, between 12:34 AM and 1:48 AM local time on August 20, 2025, the Great Firewall engaged in an abnormal behavior by unconditionally injecting fake ' RST+ACK packets ' (packets requesting a communication reset) into port 443, the standard port for HTTPS communication.
As a result, when attempting to connect to a website inside China from outside China, or vice versa, using port 443, users experienced frequent packet loss and interruptions, making it impossible to maintain a stable connection.
This behavior reportedly continued for approximately 74 minutes, after which the process returned to normal.
According to GFW Report, this particular attack targeted port 443, and other ports such as port 22, used for SSH, and port 80, used for HTTP, were not affected.
This is in contrast to the 2020 incident in which all ports from 1 to 65535 were blocked.
In 2025, it was revealed that particularly strict regulations had been imposed in Henan Province, one of the country's leading industrial regions.
Regional censorship in China has been strengthened, or internet blocking in Henan province has increased 10 times compared to other regions - GIGAZINE
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