As of May 2026, at least four major CDN providers — Google (fronted via www.google.com), Fastly (fronted via www.python.org), Vercel (fronted via nextjs.org), and Netlify/CloudFront (fronted via kubernetes.io) — route requests based on the HTTP Host header regardless of the outer TLS SNI, enabling domain fronting across more than 20 distinct high-value destinations. The correct fronting SNI for each CDN is selected by inspecting the SAN list of the CDN edge certificate and choosing a co-hosted domain the censor permits.

On non-rooted Android, user-installed CA certificates are honored by Chromium-based browsers natively and by Firefox only after enabling a hidden debug toggle ('Use third-party CA certificates' in Secret Settings), but are not trusted by native apps that use certificate pinning. This restricts MITM-DomainFronting to browser sessions on non-rooted devices and means standalone apps such as the Google Meet native client cannot be fronted without root access.

README / Android setup and warnings evaluation

MITM-DomainFronting achieves fully client-side domain fronting without any server-side infrastructure by intercepting browser TLS via a user-generated personal CA, reading the plaintext HTTP Host header, then re-encrypting outbound connections to the CDN edge with a mismatched SNI. The private CA key never leaves the device, eliminating the traditional requirement for a proxy co-located inside a CDN's network and reducing operational cost to zero.

README / Mechanism description defense

The SNI-to-destination mapping in MITM-DomainFronting is hand-curated by inspecting CDN certificate SAN lists with no automatic discovery; the author explicitly flags that these mappings must be refreshed whenever a CDN changes its SAN list or edge topology. This maintenance burden is evidenced by 20 versioned releases published in under five months (through May 18, 2026), making the config effectively a continuously-updated snapshot of 'what CDN fronting pairs are valid from Iran this week.'

README / Limitations evaluation

MITM-DomainFronting reached 1.8k GitHub stars and 170 forks by May 2026 and was merged into Xray-core mainline (PR XTLS/Xray-core#4348), making it deployable via a standard v2rayN/v2rayNG JSON config with no separate install step. The author additionally notes that Gemini explicitly IP-blocks Iranian addresses, demonstrating that certain Google services enforce IP-geolocation blocking at the application layer — a layer that SNI-based CDN fronting cannot bypass regardless of the fronted SNI.

README / intro and limitations deployment

The paper identifies a fundamental architectural vulnerability in single-IP circumvention designs: a relay must generate new observable flows (via DNS or TLS SNI) to reach end services after receiving client connections, creating a detectable server-and-client behavioral contrast. A relay accessing user-facing domains (news, social media) scores high on a Relay Suspicion Score (w=0.9) versus infrastructure domains (w=0.1). The paper argues this host-level signal is censorship-invariant and cannot be concealed by link obfuscation.

2026-almutairi-server §2.4, §4 traffic-shapedpisni-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 report maps specific Belt and Road Initiative Digital Silk Road projects through which Chinese technology vendors have transferred censorship and surveillance infrastructure to Iran, including fiber backbone investments, data-center co-location agreements, and equipment supply chains. Specific vendors named include Huawei and ZTE as network infrastructure providers, with the report noting that equipment exports include filtering-capable hardware that Iran's ISPs have deployed at network choke points.

2026-article19-tightening-the-net §4, §5 dpisni-blockingthrottling

Despite AWS, Google, and Microsoft having publicly withdrawn CDN-level domain-fronting support to preserve commercial relationships with censoring states, domain fronting remains functional on AWS Lambda as of early 2026. Microsoft Azure Functions explicitly rejects mismatched SNI/Host headers, whereas AWS Lambda permits a client to present a legitimate *.lambda-url.*.on.aws SNI while routing internally to a different serverless function via the HTTP Host header.

2026-kang-censorless-serverless §4.7 sni-blocking

CensorLess vanilla mode costs $0.27/month for a single proxy processing 6.76 GB of traffic monthly, a 97.1% reduction (34.4×) over SpotProxy's optimal single-NIC configuration ($9.28/month). The private mode, which adds a t4g.micro EC2 VPS for end-to-end encryption via SOCKS, costs $3.41/month — still 63.3% cheaper than SpotProxy's cheapest option. Costs remain below $3.50/day even when scaling to 300 proxies.

2026-kang-censorless-serverless §6.3, Figure 6 ip-blockingsni-blockingdns-poisoning

Both Firefox and Chromium leak cleartext DNS before establishing encrypted DNS connections: they first send an unencrypted UDP DNS query to resolve the DoH server's domain (e.g., doh.opendns.com). An in-path censor can intercept and poison this initial query, making encrypted DNS in browsers completely ineffective without additional circumvention of the resolver-lookup step. Additionally, Chromium always includes the SNI extension in the encrypted DNS TLS handshake (e.g., "doh.opendns.com"), leaking the resolver identity even after the initial lookup. No resolver requires SNI to be present for certificate validation when the resolver's IP certificate is configured.

2026-lange-towards §2.4, §7, §10 dns-poisoningsni-blocking