On the Internet there are falls that are noticed. And then there is what happened in China. For a whole hour, one of the main road traffic with the outside stopped working without explanation. It was not a total blackout, but a cut that became visible in many parts: applications that were halfway, websites that did not respond, services that failed right in the border crossing. The ruling did not fit with the typical local fall or with a problem of a single operator. It lasted 74 minutes, crossed networks and left behind an awkward silence.
What fell was not all the Internet, but a concrete and widely used part: the channel that allows encrypted connections to function safely. According to GFW Report, between 00:34 and 01:48 of August 20, Beijing Time (UTC+8), a generalized blockade was recorded in port 443, which is the one that uses the majority of HTTPS traffic. The effect was broad and sustained, but did not affect other channels. The most striking thing is that, until now, no one has explained what caused that cut or why it happened in that strip.
The technical analysis points to a very concrete pattern. Every time a connection tried to settle in that port, special packages – the RST+ACK – appeared that act as a closing order. They are the digital equivalent to hang the phone before someone attends. These packages were not sent by mistake: they were being injected into large quantities just at the key moment of the exchange between client and server. According to the specialists, this alteration did not fit with a fall due to congestion and affected both connections that came out of China and to those trying to enter.
Despite the serious cut, not everything stopped working. Internal connections within China were still active, and other ports, such as 80 – for non -encrypted traffic – or 22, intended for remote connections, showed no block signs. The problem was focused on port 443. That explains why some services could continue to work while others became inaccessible: it was not a total disconnection, but a very selective interruption of the encryption step that crosses the digital border of the country.
There are no public reports that indicate that platforms such as Wechat, Baidu or Weibo suffered a generalized fall in that strip; Its main infrastructure is mostly within the country and does not depend on the international crossing for basic functions. But many Chinese apps incorporate components that depend on Servers outside of China-action, mini-programs, external APIS or cloud functions-and those calls could fail when the encrypted step was blocked.
There are no public reports that indicate that platforms such as Wechat, Baidu or Weibo suffered a general fall in that strip
The impact was more noticeable in international services. According to The Register, part of the connections of foreign services – including some functions of Apple or Tesla – could be interrupted for users in China during the blockade window. Other international services that depend on HTTPS, such as certain CDNS or VPN connections that use TCP/443. In summary: the internal network was not broken, the encrypted channel was cut out and that was enough to leave many out.
One of the most relevant clues is precisely that technical footprint. Each system that filters or interrupts connections leaves a trace – a fingerprint– Recognizable for the order of the packages, the TTL or the TCP window size. In this case, these values differ from the previous documents, so the researchers propose two hypotheses: a new equipment deployed for tests or a known team that was in an anomalous or poorly configured state. The conclusions remain in condition until there are more data.
Traffic returned to normal and there were no visible consequences on a large scale.
But the cut was real, it was documented and left an unknown in the air. There were no officials or official explanations. In any case, the great firewall is still there, functioning as always, and with an intervention capacity that this time was recorded.
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