A subsystem design doc describes an outbound proxy gateway for identity-authenticated users that performs IP access control, extracts the destination domain from the ClientHello SNI (without decrypting), resolves it via an overseas DNS server, and rewrites the destination IP to route traffic abroad through a 'dedicated network' — defaulting to a WireGuard VPN interface (wg0) and falling back to a 'covert network line' via a SOCKS5 proxy when the VPN line's bandwidth cap is exceeded.

TSG automatically generates recurring weekly "SNI Report of Overseas APP" and companion "Server IP and Location of Overseas APP" reports at what is almost certainly a China-national (not export-customer) scale — single weekly runs process from ~5.7 trillion to over 135 billion rows and up to ~775TB/week — breaking down QUIC.SNI/SSL.SNI/HTTP.Host traffic per named blocked-in-China platform (YouTube, Facebook, Google, Twitter, Instagram, Telegram, WhatsApp, Netflix, BBC, Viber, Line, Snapchat, Gmail, HBO, and more), down to individual CDN edge hostnames (e.g. specific scontent-*.fbcdn.net and rr*---sn-*.googlevideo.com nodes ranked by bytes). The report series recurs weekly from at least Feb 2023 through Mar 2024.

A dedicated internal "运营商前端分析团队" (Carrier Front-end Analysis Team) produces weekly, carrier-specific traffic-analysis reports explicitly titled "新疆移动流量分析报告" (Xinjiang Mobile Traffic Analysis Report) and "新疆联通流量分析报告" (Xinjiang Unicom Traffic Analysis Report), with instances dated from at least July 2022 through March 2024. One instance (Xinjiang Mobile, 2023-05-15) reports total carrier bandwidth of 4.4Tbps (1Tbps access bandwidth), 27.34PB of weekly throughput, 123 distinct identified application-layer protocols, and a section (4.1, pages 17+) explicitly tracking server IP/location for 28 named overseas apps (BBC, Discord, ESPN, Facebook, Gmail, Google, Hulu, Instagram, Netflix, Reddit, Skype, Telegram, Twitter, Uber, WhatsApp, Wikipedia, YouTube, Zoom, etc.).

An internal module spec describes a proxy for authenticated/authorized users to reach overseas ('境外') services: it extracts the true destination domain from the TLS ClientHello SNI, resolves it via a normal public DNS resolver, forwards traffic (L4) to the real IP over a 'dedicated network,' rate-limits by client IP, and dynamically picks the lower-latency of two dedicated-network paths -- a 'VPN leased line' and a 'covert network' (隐蔽网络). Non-SNI TLS connections to the proxy are immediately closed (FIN), and the deployment does not yet support HTTP/3/QUIC.

An internal security-research presentation surveys published CDN-abuse techniques relevant to censorship evasion -- 'Domain Borrowing' (Black Hat Asia '21) and 'Domain Shadowing' (USENIX Security '21, explicitly labeled by the presenter as a 'new-type censorship-evasion technique,' 新型审查绕过技术) -- both exploiting CDNs' failure to verify accelerated-domain or origin ownership so that traffic with SNI==Host==a high-reputation domain reaches an attacker- or circumvention-controlled origin, and closes with concrete CDN-hardening recommendations (verify domain/origin ownership, set a distinct Host header on origin fetch, reject default-site requests with 403).

A MESA Lab monthly-report task list includes the next-step item 'design a scheme to identify forged/spoofed SNI in traffic' ([SNI判别]), alongside a separate active/passive traffic-fingerprinting project ('CAM-TEST') that extracts service banners passively and issues active host/port CGI GET probes.

An internal measurement-study report documents researchers live-testing the public DPYProxy TLS/SNI record-fragmentation tool against the GFW from inside China, against a control run from a German VPS. On a GFW IP-blocklisted Wikipedia IP, SNI fragmentation of any tested size (1/5/10/20 bytes) still ended in a server-side RST (though 1-5 byte fragments reached ServerHello before RST vs. 10-20 byte fragments RSTing right after ClientHello); on a non-blocklisted IP for the same domain, SNI fragmentation fully bypassed SNI-based blocking and returned a normal HTTP 200 response, matching the Germany baseline. The same report notes that testing Psiphon triggered roughly 5-10 minutes of residual censorship that also blocked other, unrelated circumvention tools from the same vantage point.