Proximax frames proxy distribution as a yield-maximization problem: the expected yield of a proxy is its attracted usage Ui divided by its total blocking risk Λi. A dissemination channel should only be assigned a proxy if the channel's own yield ratio u/λ exceeds the proxy's current yield ratio; otherwise the added risk outweighs the additional traffic and the channel must not be used at all.

Channel blocking risk in Proximax is modeled as an independent Poisson process with rate λj; when a proxy is advertised on multiple channels simultaneously the risk parameters add (Λi = γ + Σλj), so each additional dissemination channel shortens expected proxy lifetime 1/Λi. The analytic result is that redundant multi-channel broadcasting is strictly suboptimal once cumulative risk exceeds the marginal usage gain.

§3.1 defense

A sophisticated censor can infiltrate a proxy distribution system, accumulate large numbers of proxy addresses and channel identities, and delay mass-blocking for weeks or months to maximize information before acting. The paper argues this is self-limiting: delayed blocking extends proxy lifetimes (benefiting system yield), and the infiltrating account's subtree reputation score degrades sharply the moment it begins blocking proxies, triggering exclusion from future proxy assignments.

§4 detection

Proximax uses fast-flux DNS — multiple IP addresses registered to one personalized domain with short TTLs and round-robin rotation — to resist channel-level DNS blocking. When a channel's domain is blocked, the system issues a fresh individualized hostname, forcing the censor to repeat discovery rather than permanently suppressing the channel with a single DNS entry removal.

§2.2 defense

Open proxy distribution registrations are vulnerable to adversary flooding with fictitious accounts that inflate yield scores via dummy connections. Proximax uses invitation-only registration with RICO-style subtree reputation scoring — a compromised sub-node taints the entire inviting user's subtree — and sub-linearly credits usage from closely clustered source IP prefixes to limit bot-driven inflation.

§2.2, §4 defense

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