OONI data shows anomaly rates in Russia's top five ASes (including Rostelecom AS12389, Vimpelcom AS8402) rose from roughly 7–11% in January and early February 2022 to 12–21% in mid-March 2022, with social-media and news domains such as Facebook, Twitter, Instagram, and BBC going from available to near-completely blocked after the invasion.

Following the invasion, Psiphon user counts and VPN usage in Russia increased many-fold and correlated with specific censorship events, while multiple access paths to Tor (direct connections, bridges, pluggable transports) were progressively blocked. Despite this surge, circumvention tools reached only a small fraction of all Russian Internet users, indicating that aggressive multi-vector blocking and lack of user awareness left most people unable to access censored resources.

§6 evaluation

Of the Tranco top-10K domains, 286 (3.26%) returned geoblocking signatures for all Russian vantage points in May 2022, with CDN-mediated blocking dominant: 87 domains via Cloudflare and 57 via Akamai. DNS-level geoblocking alone affected 68 domains, and 29 domains implemented both DNS and TCP geoblocking simultaneously, rendering public-resolver circumvention of DNS blocks ineffective for those targets.

§5.1 evaluation

On March 28, 2022, Russian ISP RTComm (AS8342) hijacked Twitter's IPv4 prefix 104.244.42.0/24 for approximately 45 minutes (12:05–12:50 UTC) and announced it to the global Internet as a blocking measure. The hijack was blunted because Twitter had preemptively registered RPKI route origin authorizations (ROAs) for its prefixes, causing RPKI-validating ASes worldwide to reject the hijacked route.

§4.3 detection

136 Russian government domains (25.09% of 542 accessible ones) blocked access to all tested countries outside Russia, and a further 112 (20.66%) were accessible only from Russian and Kazakhstani vantage points. Geoblocking was implemented via heterogeneous, uncoordinated mechanisms—DNS timeouts, TCP timeouts, HTTP 403 Forbidden responses, and explicit blockpages—across different domains, indicating an ad hoc emergency response with no central policy.

§4.2 deployment

Table 1 of the survey documents that by 2013–2014 censors were deploying simultaneous blocking across BGP, DNS, IP/port filtering, TCP disruption, TLS, and application-layer keyword filtering. No single detection tool in the survey covers all six layers; the most comprehensive, OONI (2012), covers DNS, IP/port, TCP, TLS, keyword, and HTTP but notes only partial BGP coverage.

2015-aceto-internet Table 1 bgp-hijackdns-poisoningport-blockingip-blockingrst-injectiontls-fingerprintkeyword-filteringdpi

The June 2025 Iran shutdown—carried out during the Iran-Israel war beginning ~June 19—did not use BGP route withdrawals as in 2019. Instead, authorities applied service-level restrictions at the national border: DNS poisoning of foreign destinations, protocol whitelisting permitting only pre-approved domestic services, and DPI to block circumvention-tool traffic. Iran's international traffic fell roughly 90% while the country's BGP routes remained advertised, making the shutdown invisible to BGP-based monitoring systems. OONI measurement volume, which totalled 121,333 in June 2025, collapsed to under 200 submissions on June 19-20.

2025-iran-shutdown-measurement Executive Summary / §2 dpidns-poisoningport-blockingip-blocking

Article 19 documents that Iran's National Information Network (NIN / SHOMA) was designed with explicit reference to China's Great Firewall as a model, with institutional mirroring: Iran's Supreme Council of Cyberspace parallels China's Cyberspace Administration of China, and both governments share a "cyber sovereignty" doctrine used to justify domestic content controls and cross-border technology transfer. The report frames Iran's filtering infrastructure as deliberately architected to replicate GFW capabilities, not as an independently developed system.

2026-article19-tightening-the-net §2, §3 dpisni-blockingdns-poisoningip-blockingbgp-hijackthrottling

Iran's censorship of refraction-networking proxies (Conjure via Psiphon) is not monolithic: different ISPs independently deploy different techniques and timelines. Over 800 million logged Conjure connections from July 2023–February 2025 across 10+ Iranian ASes show TCI (AS58224, ~33% of traffic) uses packet injection, while MCCI/Hamrah-e Avval (AS197207, ~22%) applies IP-based blocking, and some ASes (Parsonline AS16322, Shatel AS31549) show no proxy blocking at all.

2025-alaraj-iran-refraction §4 rst-injectionip-blockingpacket-injectiondpi

TTL-based path analysis showed that all censorship actions (DNS poisoning, HTTP injection, TLS resets) in the June 2025 shutdown occurred at the same network hop across all tested ISPs, indicating a single centralized national border gateway—likely TCI AS gateways—rather than per-ISP enforcement. Global BGP announcements were kept intact throughout, making the shutdown invisible to routing monitors while domestic connectivity collapsed.

2025-aryapour-stealth-blackout §4.5 dpidns-poisoningrst-injection

GFWeb tested 1.02 billion domains against the GFW over 20 months and discovered 943,000 pay-level domains blocked by HTTP filters and 55,000 by HTTPS filters — the largest GFW blocklist dataset ever published. The HTTP-to-HTTPS ratio (17:1) confirms that the GFW's HTTPS keyword-based and SNI-based blocking covers far fewer domains than its HTTP host-header blocking, likely because HTTPS blocks carry higher collateral-damage risk.

2024-hoang-gfweb Abstract, §5.1 dpidns-poisoningip-blockingkeyword-filteringsni-blocking