Routing traffic from a user on ISP-B through a peer relay on ISP-A (which applied only HTTP-level filtering and permitted HTTPS) produced the smallest page load times in most cross-ISP comparison runs, beating both HTTPS/domain-fronting and Tor. The performance gain is attributed to lower end-to-end latency on the intra-country cross-ISP path relative to international relay routes.

Direct circumvention via HTTPS/domain-fronting from Pakistan achieved an average throughput of ≈1.5 Mbps, whereas static proxies located in the US, Europe, and Asia yielded less than 0.9 Mbps in most cases. Page load times for the YouTube homepage (≈360 KB) were significantly lower under the direct method, and a TCP slow-start model predicts throughput could reach ≈2 Mbps if the flow completed within slow start.

§3.2 / Figure 1 / Table 2 evaluation

Across two major Pakistani ISPs, blocking mechanisms varied substantially for the same URL: ISP-A applied HTTP-level blocking with redirection to a block page, while ISP-B deployed multi-stage blocking combining DNS-level resolution to localhost and independent HTTP/HTTPS request dropping. A single ISP also used different filtering techniques for different URL categories (e.g., YouTube vs. HTTPS-accessible sites).

§3.2 / Table 1 evaluation

C-Saw's design demonstrates that coupling circumvention capability with censorship measurement creates a self-reinforcing incentive loop: users opt in for improved page load times, their participation grows the vantage-point pool, and richer measurements enable finer-grained technique selection per ISP and URL. The system avoids requiring a pre-populated URL list by building a blocked-URL database dynamically from user-initiated requests.

§1 / §3.3 / §4.2 defense

In experiments using 200 back-to-back fetches of the YouTube homepage (≈360 KB), HTTPS produced lower page load times than Tor in most cases because Tor circuits do not optimize for performance and often select longer paths. Tor's page load times varied widely as circuits changed approximately every 10 minutes, producing a heavy tail in the latency distribution.

§3.2 / Figure 2a 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