The 16-Kbyte trick: Russian providers block foreign content again

Russia has apparently been blocking Western cloud providers and CDNs with new tricks since the beginning of June. The CDN provider Cloudflare has recorded significantly fewer accesses from the increasingly shielded country and attributes this to secretly implemented blocking measures. However, there is no official confirmation from either the Russian government or the local internet providers.

An analysis of network traffic to Russia has shown that it has collapsed by fifty percent in some cases since June 9, 2025. According to the network experts, affected websites and services are de facto unusable for users because The filtering measures only allow 16 KByte of each file through and then regulate the data traffic. For comparison: the HTML document of the heise-online homepage alone is 118 KByte in size. Internet users who want to access websites in the Cloudflare CDN from Russia therefore only receive fragments.

But it is not only the data volume that has fallen sharply; according to Cloudflare, other indicators also point to a blockade: the "network error logging", error data voluntarily transmitted to the CDN by browsers and internal statistics. An error diagram shows the massive deterioration in network quality, with packet loss hovering between 70 and 80 percent. This error rate is unacceptable for demanding Internet applications.

Not only the US provider Cloudflare is affected, but apparently also DigitalOcean, Hetzner and OVH. It is unclear whether the blockade is only temporary or permanent. Official confirmation is also pending: Neither the Russian government nor the providers allegedly involved have commented. Cloudflare admits that it currently has no solution – Russian users should contact the local authorities to lift the blockade.

Use a domestic solution – but which one?

The Russian strategy behind the blockade is to be as little dependent as possible on foreign providers and Internet services. The RUnet, a self-sufficient Russian Internet, is the government's declared goal, but there are also critical voices. Although the supervisory authority Roskomnadzor (RKN), which orders internet blockades and monitors their implementation, has been warning against the use of Cloudflare CDN since the end of 2024, there is no domestic alternative to the US service. RKN already had Cloudflare blocked last November in protest against the introduction of a new TLS feature to increase privacy.

In addition, 18 other EU publications have recently been blocked in Russia, reports the Russian business newspaper Kommersant. It is not known which ones, according to the report. The blocklist of the Russian telecommunications authority Roskomnadzor is currently either offline or cannot be accessed from outside Russia. It is unclear whether the two blockades are connected.

(cku)