Hysteria 2 (QUIC-based proxy) suffered past large-scale GFW blocking events but was broadly functional as of late 2024. Aggressive packet sending causes VPS providers and ISPs—not the GFW itself—to apply rate limits, adding a second failure mode beyond censor detection.

CDN-based proxy protocols avoid permanent IP-level GFW blocking but suffer from instability. IPLC ('no wall crossing') leased lines are stable and fast but expensive and subject to periodic administrative disconnection by the Chinese communications regulator.

Comment by @RPRX, Nov 18 2024 evaluation

REALITY ('certificate stealing') had produced no large-scale GFW blocking reports as of November 2024, per Xray-core developer @RPRX. Its operational downside is lower throughput compared to aggressive packet-dispatch protocols like Hysteria 2.

Comment by @RPRX, Nov 18 2024 evaluation

Raw UDP P2P gaming traffic was detected and blocked within 1–2 hours. Hysteria 2 port-hopping delayed blocking but the entire server IP was eventually blacklisted once enough ports were consumed. The reporter identified udp2raw + WireGuard (with udpspeeder for packet loss compensation) as the most stable high-performance solution.

Comment by @iopq, Dec 1 2024 deployment

XTLS Vision has never triggered large-scale GFW blocking; one user reports 2.5+ years of uninterrupted use. Developers acknowledge that Vision without Seed produces fixed, distinguishable traffic characteristics and are developing 'Vision Seed' to introduce per-session randomization.

Comments by @RPRX and @terada46, Nov 18–20 2024 evaluation

In April 2026, Russia nearly completely blocked Telegram, reducing availability without VPN to 5% during the first ten days; Russia's VPN user base was estimated at no less than 40% of the population. Beginning in mid-April, over 20 major Russian websites and platforms (including Gosuslugi, Ozon, Yandex, Sberbank, VK) began restricting access for VPN users, and Russia introduced a whitelist-based service model permitting only state-approved services under certain network restriction states.

2026-anon-2026-27-vpn §4 (俄罗斯 Telegram / OSW section) ip-blockingdpithrottling

After the shutdown lifted (Scan 3), DNS-over-UDP degraded severely — 89.18% of the 9,000 queried domains were affected — but the paper attributes this to general UDP transport instability rather than domain-specific censorship, corroborated by GitHub user reports of ongoing UDP issues. TCP-based protocols (HTTP, TLS) returned to pre-shutdown censorship levels (~15%) in Scan 3, confirming the post-shutdown persistence effect was UDP-specific and not a broadening of the blocklist.

2026-anon-insights-into-iranian §2.2.4, Table 1 throttlinghttp3-quic-block

Iran's June 2025 shutdown was enforced using fine-grained, service-level techniques rather than BGP withdrawals or a single 'big switch' event: individual protocols were selectively blocked before and after the 7-day full blackout (June 18–25), with the total preparation and recovery periods each lasting roughly 4–5 days. Cloudflare Radar showed HTTP traffic reaching near-zero by June 18 but partial recovery already on June 21, while the authors' vantage point (AS57497) remained unreachable until June 25, confirming heterogeneous recovery across Iranian networks.

2026-anon-insights-into-iranian §2, §3 dpihttp3-quic-blockthrottling

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

The April 2026 enforcement cycle created a resource-scarcity feedback loop: upstream providers cut lines with no obligation to refund resellers, newly acquired replacement resources can themselves be reported and cut within days, and stable-resource availability windows are described as "越来越短" (increasingly short) while costs rise concurrently. The overall effect is systemic capacity contraction forecast to continue through at least May 2026.

2026-ermao-april-airport-outage §这轮波动到底发生了什么 / §四月后的趋势判断 ip-blockingasn-blackholingthrottling