QUIC / HTTP/3 blocking

An internal TSG functional-requirements spec ('加密协议JG') defines device support for identifying and blocking ECH, ESNI and QUIC traffic via per-connection SNI/region-matching tables (e.g. DF_QUIC_REGION), plus a companion 'FD报文全流程感知' feature that both passively monitors and actively injects synthetic verification traffic end-to-end through the network path to compute a live per-rule 'CT率' (breakthrough/penetration rate) — the system self-measures how often its own QUIC/ESNI/ECH blocks fail to take effect, and separately throttles logging/blocking detail for rule IDs receiving unusually high hit counts (DF_ATTACK_PROTECTION, 'targeted attack detection').

An internal experiment using BurpSuite as a MITM proxy tests injecting a forged QUIC ServerHello carrying a connection-close frame ahead of the real server response, to make the client abandon its QUIC handshake; the author separately proposes recording every site known to support QUIC and simply blocking plain TCP connections to those sites, on the theory that this indirectly forces QUIC off since a censor cannot otherwise tell in advance which TCP flow would have upgraded to QUIC.

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.

The Xinjiang Mobile carrier traffic report (2023-05-15) states in its own QUIC-domain-ranking section that Xinjiang's intra-provincial traffic has begun carrying QUIC/HTTP3 (UDP-based) traffic that poses "a huge challenge" to the traditional parallel/out-of-band ("并联") traffic-access blocking method, and that effectively gatekeeping ("GK") UDP/QUIC traffic requires switching to an inline/in-path ("串联") blocking architecture — a direct internal admission that (as of mid-2023, in this province) the standard mirror-tap deployment could not reliably block QUIC.

Recurring automated "Tiangou Secure Gateway — SNI Report of Overseas APP" documents (weekly, multiple recurrences across 2023-2024) enumerate every distinct QUIC.SNI/SSL.SNI/HTTP.Host value observed per major foreign platform (Netflix, WhatsApp, Telegram, Twitter, YouTube, Signal- adjacent services, etc.) with packet/byte counts, processing runs at up to ~6.3 trillion rows per report. QUIC SNI is tracked as a distinct column from TLS SNI, showing the pipeline separately fingerprints HTTP/3 traffic.

A production feature spec ("加密协议JG") requires detection-and-control capability for QUIC, ESNI, and ECH, with a per-connection log field c_encrypt_type explicitly distinguishing ClientHello encryption (0=unencrypted, 1=ESNI, 2=ECH) and a DF_QUIC_REGION rule table matching QUIC by SNI. The system computes a per-rule "CT" (穿透/penetration) rate from paired mirror-vs-functional RST-packet logs (TF-RST-LOG / TF-MIRROR-RST-LOG) to grade each block rule's effectiveness, and runs continuous active-verification probes against its own rules, deliberately varying the probe 4-tuple each run "to ensure it doesn't hit the blacklist" so the verification traffic itself reaches the target.

A MESA Lab thesis/report states that ESNI/ECH protocol-identification technology, based on TLS extension field type numbers, "has already been applied in actual projects," and lists the researcher's own project participation as "G1系统 - ESNI、ECH加密协议识别" (Feb-Aug 2023) and "G1系统 - QUIC协议旁路ZD" (Feb-Nov 2023, QUIC bypass/blocking), plus a separately implemented "DNS主动探测模块" (DNS active-probing module, marked 已实现/already implemented). "G1" also appears independently as a named legacy system in the Maat/Transformer DPI header (PROTO_VPN comment: "G1历史遗留"), corroborating it as a real internal system name, not a typo.

Weekly Xinjiang Mobile carrier-side traffic analysis reports (2022-2023) state in plain internal language that HTTP/3 (QUIC-over-UDP) traffic 'poses a major challenge' to the traditional parallel/mirror (并联) traffic-access blocking method, and that UDP traffic requires an inline/serial (串联) blocking deployment to 'effectively' block it -- a direct admission that passive mirror-tap deployments (the apparent default) cannot reliably block QUIC-based traffic, only inline in-path deployments can.

MESA_Platform's "quic" module (built and packaged as stellar-on-sapp/sapp RPMs) implements SNI/User-Agent extraction from both cleartext GQUIC (versions 23-59) and encrypted IETF QUIC RFC9000 ClientHello payloads, and supports a QUIC SNI whitelist -- i.e. the DPI pipeline decrypts/parses encrypted QUIC handshakes to recover the destination domain rather than being blocked by QUIC's encryption.

Project "E21" tested SNI-FQDN-wildcard block policies against international news/media/academic domains -- opride.com (Oromo news), ethiotube.net, Reuters, NYT, Bloomberg, GitHub, ResearchGate, NIH.gov -- from an Ethio-Telecom-range office IP. Most blocks silently failed (shared root cause with OMPUB-466); britannica.com needed a separate deny-quic policy since QUIC bypassed SNI blocking.

Signature extraction for named circumvention tools (Freegate, Psiphon, Ultrasurf, Tor Browser) explicitly captures QUIC SNI alongside TLS SNI and HTTP Host header, confirming TSG's fingerprinting pipeline covers QUIC transport, not just TCP/TLS.

A MESA Lab researcher maintains a small repo explicitly named "quic-block" (LiFulian/quic-block) containing a single C++ source file "quic_lfl.cpp", indicating standalone development work on QUIC/HTTP-3 blocking logic; the repo's minimal size (5 files) and "studyGit" commit suggest early-stage or personal research rather than a shipped product module, so this should be read as evidence of active R&D interest rather than a confirmed deployed capability.

A raw sapp deployment/config script shows an operator toggling `kickout_udp_stream_enabled=0` to `=1` in sapp.toml (via sed, in place on a live tsg-traffic-engine-vsys-1 install), alongside RPM upgrades of sapp's ssl/firewall/dtls/utable/libmaatframe components, and separately disabling SEND_SESSION_RECORD and SEND_FILE_STREAM_RECORD logging flags in main.conf — confirming sapp has an explicit, operator-toggleable feature to actively terminate UDP streams it flags, independent of whatever passive detection triggered the flag.

A previously-undocumented sapp plugin named 'Stellar' (repo stellar/quic_decoder, packaged as stellar-on-sapp, depending on sapp-devel and OpenSSL) implements 'quic_deprotection' — QUIC packet-protection removal — as a component distinct from the older MESA_Platform/gquic plugin, sharing the same test corpus of GQUIC/IETF-QUIC pcaps (RFC9000, chlo-fragment, no-SNI cases). This is a candidate new product entry for the taxonomy: a second, apparently newer QUIC-inspection engine alongside gquic.

The "stellar" QUIC decoder plugin implements a complete RFC 9001 QUIC Initial-packet header- and payload-deprotection pipeline (HKDF key derivation from the well-known public IETF/gQUIC initial salts, AES-128-GCM payload decryption, AES-CTR header-protection removal) to decrypt QUIC ClientHello messages in real time, reassembling CRYPTO frames fragmented across multiple UDP datagrams, and extracts SNI and User-Agent from the decrypted handshake. It separately parses legacy Google QUIC (gQUIC) CHLO tag-value blobs (TAG_SNI / TAG_UAID) for older/non-IETF QUIC variants, and recognizes version ranges for a long list of QUIC implementations (mvfst, quant, quicly, msquic, mozquic, picoquic). A config flag (DECRYPTED_SWITCH) toggles whether the decrypt-and-inspect pass runs.

Two independently-leaked TSG session-log CSV exports share an identical 224-field schema whose proxy_* columns (proxy_action, proxy_pinning_status, proxy_intercept_status, proxy_cert_verify, proxy_intercept_error) log the outcome of TLS interception per session, alongside ssl_ja3_hash/ssl_ja3s_hash, ssl_esni_flag, ssl_ech_flag, and quic_sni fields — confirming MITM/cert-pinning-bypass instrumentation and TLS/QUIC fingerprinting are built into TSG's standard traffic-logging pipeline, not a bolt-on feature.

A TSG-Application blocklist test found that disabling Facebook/Twitter in TSG's per-app policy did not stop Psiphon3 traffic from reaching those services in practice, because Psiphon3's dual-stack fallback drove the tunneled Facebook traffic over IPv4 QUIC, which TSG's classifier failed to attribute to Facebook -- in contrast to Taobao/Bilibili/Youku/JD, which TSG blocked successfully in the same test.

TSG runs a recurring, fully-automated weekly analytics job -- literally titled 'Tiangou Secure Gateway SNI Report of Overseas APP' and a companion 'Tiangou Secure Gateway Server IP and Location of Overseas APP' report -- that processes roughly 300 billion to 10 trillion traffic rows per week and produces per-platform SNI and server-IP/location breakdowns (Top10/Top50) for YouTube, Facebook, Google, Twitter, Instagram, Telegram, WhatsApp, Viber, Line, Messenger, Snapchat, Gmail, HBO, Netflix, Discord, BBC, Bigo, ESPN, and Hulu, plus a dedicated Top-100 SNI table for QUIC-protocol traffic.

TSG's Ansible deployment platform ('tsg/tsg-scripts-platform') installs per-protocol firewall RPM modules -- dedicated dns, ftp, http, mail, quic, and ssl packages -- alongside the sapp DPI engine and mrzcpd packet-mirror/inject agent, confirming TSG ships a purpose-built QUIC/HTTP3 blocking module as a first-class protocol-firewall component.