2025.8.20 Quick Report | GFW Suspected of Large-Scale Interference with Port 443 Connections

Starting tonight, users in multiple locations have reported that China’s “Great Firewall” (GFW) appears to be implementing high-intensity interference on port 443, mainly manifested as severe packet loss and connection timeouts. The specific situation is as follows:

Outbound access to domestic: When connecting to websites in China through port 443 (commonly used for HTTPS), frequent packet loss and disconnection occur, unable to maintain stable connections.

Domestic access to outbound: Domestic users also report being unable to access foreign sites through port 443, with the HTTPS connection establishment failure rate increasing significantly.

Port 80 normal: In comparison, access using port 80 (HTTP) remains basically normal, indicating the interference is mainly concentrated on port 443.

Currently, the technical community generally speculates that this phenomenon may be related to network policy adjustments or firewall rule changes; the specific cause remains to be confirmed, and its impact scope and duration remain to be further observed.