TSG deployments include an inline optical-bypass failsafe (光保) that, on link/health failure, can leave the segment in bypass (fail-open passthrough) mode rather than reverting to inline inspection — a 2023 incident at E21 (MSH-TSGX-02, 120Gbps) had a bypass segment stuck open until manually tuned.
查对应光保(10.10.20.121)一条链路状态为down...发现其当天最后一次切bypass后没有切回inline...已调整该Segment的保活间隔为50ms,切bypass的阈值为10次
Defense implications
- Confirms TSG's physical bypass failsafe is fail-open by design (unfiltered passthrough on failure/overload), consistent with the CPU-triggered bypass behavior seen in the YouTube-deny finding — this is an architectural property, not a one-off bug.
Related findings
Ethiopia (E21) customer specifically tested Melon VPN and Ultrasurf against TSG; Ultrasurf's frequently-rotating IPs required an updated signature (successfully blocked after update), while Melon VPN's connection succeeded but was non-functional for other reasons (not attributed to TSG blocking).
Confirms the full licensed TSG component roster deployed at Ethiopia (E21): Firewall, Digital Observer, Email Retention, Statistics Policy, Proxy, Session Record, GTP Security, AppSketch, AppSketch Engine, AppSketch DB, WebSketch, WebSketch DB. Several license terms were extended to expire 2091-12-31, indicating a multi-decade commercial commitment.
Side-by-side internal performance comparison across Xinjiang (China Mobile carrier deployment, hostname cmcc-xj-server1-sapp-244), Fujian (domestic), and Ethiopia (E21) explicitly references the same 'app_sketch_maat' diagnostic log format at all three sites, confirming the identical AppSketch app-fingerprinting stack is used for domestic Xinjiang surveillance and for the exported Ethiopia deployment.
Direct dated evidence (July 2023) that the Ethiopia (E21) customer actively toggles application-level blocking as a live policy lever: lifting the block on YouTube plus four other apps caused a documented traffic surge and device alerts at the BOL-IGW site.
A certificate-issuance repo (luwenpeng/certificate, commit "TSG-8365 为TSG/Nezha界面的服务端签发证书" = "issue server-side certs for the TSG/Nezha interface") contains config, CSR, key, and crt files explicitly named "-for-e21" (ca-root-for-e21.conf, tsg-entity-for-e21.crt, nezha-entity-for-e21.key), confirming an internally-issued PKI hierarchy used for encrypted communication between TSG and its "Nezha" management-web-interface components at a site tagged E21 (Ethiopia).
A TSG "device_group" tag configuration enumerates 30+ Ethiopian deployment sites far beyond the previously-known E21 site list, including many new city/PE (provider-edge) codes (Ambo, Nekemte, Yeka, Arada, Jijiga, Dessie, Mekele, Debre Markos, Gondar, Hawasa, Sodo, Jimma, plus GGSN nodes at Microwave/Kirkos/Nefas Silk) alongside the already-documented sites (Bole, Shashamane, Bahir Dar, Dire Dawa, Legehar, Old Airport, Nefas Silk). Two entries are explicitly labeled "Safaricom Kaliti IGW" (KLT-IGW) and "Safaricom STEP HQ IGW" (STQ-IGW), directly confirming the Safaricom Ethiopia customer identity for the E21 deployment from primary device configuration rather than inference.