In a traffic sample from a major non-anonymous circumvention tool (3.56 TB total, Feb 21, 2008), 48% of all proxied traffic belonged to websites that were not censored in Iran. Integrating CacheBrowsing to fetch CDN-hosted censored content directly further saves 41% of Buddy bandwidth for Alexa top-1000 websites.

Survey data indicates 31% of Chinese Internet users use VPN services compared to Tor's approximately 2 million daily users globally, and centralized non-anonymous systems like Lantern and Psiphon dominate adoption over anonymity-focused tools. The paper argues this demonstrates that the majority of censored users prioritize blocking resistance over anonymity, supporting a separation-of-properties design principle.

§III-B policy

The majority of censored websites are blocked in only one or two countries, with political and news content showing the strongest geographic specificity. Figure 3 shows that of domains blocked in China, Iran, and Turkey, only 29 are blocked in both China and Turkey, while 27,852 are China-only and 1,564 are Iran-only, demonstrating that cross-region client-to-client proxying is broadly applicable.

§III-C, Figure 3 evaluation

MassBrowser proxies operate on NATed IP addresses shared with other users and services, meaning blocking them imposes collateral damage on unrelated parties. The proxy IP pool scales linearly with user count via client-to-client proxying, and IPs rotate as volunteers move between networks, making enumeration-and-block strategies progressively more costly for censors.

§III-E, §IV-A defense

MassBrowser estimates operational cost at $0.0001 per active client per month at large scale; the domain-fronted Operator alone costs ~$0.001 per active client per month because signaling traffic volume is small. Domain fronting used for bulk data proxying is characterized as prohibitively expensive and not viable at scale.

§III-E, §VI-C evaluation

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

The GNL reveals that Geedge actively maintains dedicated VPN-infrastructure tracking datasets. The China-specific component includes 7,016 domains in a "vpn-finder-plugins" repository (mesalab_git/intelligence-learning-engine), 4,810 NordVPN server domains, and a Pakistan-specific file listing 68 Psiphon CDN domains (geedge_docs/TSGEN/.../Psiphon-CDN_20240430.json) dated April 2024. A Myanmar deployment file (M22-VPN List.html, 27 domains) further confirms country-specific VPN blocklists are operationally maintained. The "Appsketch" program reverse-engineers VPN apps to extract domains and IP addresses for blocking.

2026-sheffey-geedge §4.2, Table 3 dpisni-blockingip-blocking

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

Amnesty International's 102-page investigation identifies a multi-vendor surveillance stack deployed in Pakistan: Chinese DPI (Geedge/MESA-derived), Canadian social-media monitoring (Netsweeper), and Emirati commercial spyware (Pegasus and FinFisher). The system enables deep packet inspection, SNI-based filtering, and traffic-shape classification at national scale, including targeted interception of encrypted messaging apps and VPN traffic.

2025-amnesty-pakistan-shadows §3, §5 dpisni-blockingip-blockingtraffic-shapeml-classifier

InterSecLab's 76-page analysis of the Geedge/MESA leak (based on nine months of indexing and translating >100,000 documents) characterizes the Tiangou Secure Gateway (TSG) product line as a commercially deployable detection stack that combines deep packet inspection, real-time mobile subscriber monitoring, active probing, ML-based traffic classifiers, and granular per-region rule sets. TSG is not a research prototype — leaked documentation includes deployment timelines and client government interactions for Kazakhstan, Ethiopia, Pakistan, Myanmar, and one unnamed country, with censorship rules explicitly tailored to each region.

2025-interseclab-internet-coup §3–§5 (InterSecLab report) dpiactive-probingml-classifiersni-blockingip-blockingtraffic-shapefully-encrypted-detect