: Great Firewall took out all traffic to port 443 at a time Beijing didn't have an obvious need to keep its netizens in the dark

Activist group Great Firewall Report spotted the outage, which it said disrupted all traffic to TCP port 443 – the standard port used for carrying HTTPS traffic.

“Between approximately 00:34 and 01:48 (Beijing Time, UTC+8) on August 20, 2025, the Great Firewall of China (GFW) exhibited anomalous behavior by unconditionally injecting forged TCP RST+ACK packets to disrupt all connections on TCP port 443,” the group wrote in a Wednesday post.

That disruption meant Chinese netizens couldn’t reach most websites hosted outside China, which is inconvenient. The incident also blocked other services that rely on port 443, which could be more problematic because many services need to communicate with servers or sources of information outside China for operational reasons. For example, Apple and Tesla use the port to connect to offshore servers that power some of their basic services.

    • Nougat@fedia.io
      17·
      24 days ago

      There’s lots of things that transport using HTTPS that aren’t websites in browsers.

    • Zykino@programming.devEnglish
      3·
      24 days ago

      Pass thoses firewalls and other corporates proxy/VPN/… that block most ports. If what you build is at least partly used where user have internet access, you know this port is open. Even if 22, 8080 and all the others are closed.

    • setsubyou@lemmy.worldEnglish
      31·
      24 days ago

      Sometimes mandatory web proxies still allow direct connections to port 443 so as to not break https, which in return means as long as your connection is to port 443, that proxy will pass it through without interfering.

      I used to run sshd on port 443 for this reason back when I regularly had to work from client networks.