IP blocking in Myanmar was non-deterministic within individual ASes: Frontiir (AS58952) blocked Facebook's IP 157.240.15.36 but not 31.13.82.36, indicating ISPs used incomplete address lists. Different websites were blocked on different networks, and DNS interference was inconsistent even within a single ISP's resolvers, confirming that censorship was decentralized rather than implemented via a national choke point.

Cellular data restrictions imposed from Mar. 15, 2021 were invisible to IODA (which uses BGP routing data, active probing, and darknet traffic) because cellular networks commonly use Carrier Grade NAT. Kentik's AS-level NetFlow aggregates clearly showed the cellular traffic drop, with all four major cellular ASes (MPT AS9988, Mytel AS136255, Telenor AS133385, Ooredoo AS132167) experiencing sustained traffic reductions while fixed-line providers only showed nightly dips.

§3.2 evaluation

Beginning Feb. 14, 2021, country-wide Internet outages affected Myanmar for 72 consecutive nights until Apr. 28, starting at 18:30 UTC (01:00 local time) and lasting 8 hours each night. These nightly curfews were highly synchronized across most ISPs—identical start and end times—in stark contrast to the haphazard, mis-timed outages on the day of the coup.

§3.2 deployment

Post-coup, Myanmar ISPs shifted from primarily DNS-based blocking (dominant in 2020) to IP-based blocking. Blocking Fastly's IP 151.101.1.195 triggered collateral unavailability of more than 10,000 co-hosted websites; blocking a Google-hosted IP (172.217.194.121) rendered snapchat.com, getoutline.org, and others unreachable on at least 4 ASes during Feb. 24–27, 2021.

§3.3 evaluation

On Feb. 5, 2021, Campana Mythic (AS136168) announced Twitter's 104.244.42.0/24 prefix—apparently intending to blackhole Twitter traffic locally as part of the national Twitter block—but the route leaked to operators in Singapore and Vietnam, causing collateral disruption for Twitter users outside Myanmar. This accidental BGP leak corroborates evidence that Myanmar ISPs were independently implementing IP-level censorship without a centralized national kill switch.

§3.4 deployment

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

Chinese users treat full proxy/VPN (Shadowsocks, V2Ray/Clash, commercial VPNs) as the '终极大杀器' (ultimate solution) for bypassing GitHub DNS poisoning, implying that lighter-weight DNS-only fixes fail in some network environments where the censor adds firewall-layer blocking beyond DNS.

2026-anon-6-github-dns §3 使用代理或 VPN dns-poisoningip-blocking

Rule-based proxy tools (Clash, Shadowsocks, V2Ray) are documented as the most reliable solution for accessing GitHub from China, with split-tunneling rules routing only GitHub traffic through the proxy while keeping domestic traffic on the direct path. Git command-line tools require explicit proxy configuration (git config --global http.proxy http://127.0.0.1:7890) to route clone/push operations, as they do not inherit system proxy settings automatically.

2026-anon-github-2026-6-dns §方法二 dns-poisoningip-blocking

The GFW blocks GitHub via DNS poisoning across at least four domains — github.com, assets-cdn.github.com, github.global.ssl.fastly.net, and raw.githubusercontent.com — causing connection timeouts and page-load failures for mainland China users. The block is persistent as of February 2026, affecting both browser access and command-line git operations.

2026-anon-github-2026-6-dns Introduction / §方法一 dns-poisoningip-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

Article 19 documents that Iran combines technical filtering with formal coercion of major foreign platforms (including Telegram, Instagram, and WhatsApp) to comply with content removal orders under threat of full blocking. The report notes that Iran's 2022 Women Life Freedom protests accelerated platform blocking when foreign operators refused compliance, demonstrating that the censorship system operates in two modes: coerce-and-allow for compliant platforms, block for non-compliant ones. Domain fronting via these platforms is therefore subject to sudden revocation if political conditions change.

2026-article19-tightening-the-net §6 ip-blockingdns-poisoningthrottling