A MESA-affiliated researcher's experiment log documents live testing of Psiphon and a TLS-fragmentation SNI-evasion tool (DPYProxy) against the real Great Firewall from inside mainland China. Fragmenting the TLS ClientHello/TCP stream into very small (1-5 byte) segments bypassed GFW SNI-based blocking of a non-blocklisted Wikipedia IP, while larger fragments (10-20 bytes) did not; a separately IP-blocklisted Wikipedia IP still failed regardless of fragmentation. Testing Psiphon also appeared to trigger a ~5-10 minute window in which the researcher's own unrelated circumvention tool stopped working.

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.

An internal "business log loading interface" spec enumerates the platform's full censorship/surveillance taxonomy as three parallel log streams (管控/blocking, 监测/monitoring, and 一般/general) each covering the same roughly 13 categories -- IP blacklist, DNS spoofing, URL, website, specific-certificate, webpage-keyword, email-keyword, FTP-keyword, search-term, email, VPN, instant-messaging, and social-app -- fed via HTTP POST/Avro to a "front-end big data platform," with source/destination geolocation fields explicitly keyed to a carrier-supplied "疆外" (outside-Xinjiang) IP-location database.

A hands-on MESA lab experiment testing TLS-record/TCP fragmentation (via the DPYProxy tool, replicating the public "Circumventing the GFW with TLS Record Fragmentation" technique) against live GFW found SNI fragmentation reliably bypasses GFW's SNI-based blocking of a non-blocklisted wikipedia.org IP, but has zero effect on GFW's separate IP blocklist: for an already-blocklisted IP, every fragment size tested still failed, with GFW tearing down the connection via <RST,ACK> immediately after ClientHello for larger fragments, or after the server's Hello for very small (1-5 byte) fragments.

TSG maintains a traffic-volume-ranked "Top SNI" / "Top Server IP" allowlist (Galaxy component, learned from live traffic, capped at top ~2000 SNIs / ~40000 server IPs per Nacos config) that is checked before a VPN/circumvention-tool deny policy (including a Psiphon3-specific policy) is enforced. Confirmed empirically: Psiphon3 client traffic whose destination SNI was in the Top SNI list passed through undenied, while traffic to the same client IPs with an SNI not yet in the list was blocked. A 2022-06 incident over-blocked TikTok/BBC/CNN/NYTimes because their SNIs were not yet in the learned allowlist at the time.

As of TSG v23.07, FQDN matching supports left-anchored prefix/wildcard matching (e.g. 'voice-group-80x-api.*'), added specifically so a Fujian domestic deployment could detect domains with a fixed subdomain prefix but rotating remainder. Earlier versions only supported exact FQDN match.

For a domestic Fujian deployment, Geedge validated SNI-wildcard blocking (*.sohucs.com, *.sns.sohu.com) as technically effective against a specific Chinese social app ('Huyou'), but rejected it for production because the domain is shared with a third-party SDK platform and would cause false-positive blocking of unrelated services -- falling back to destination server-IP blocking, deployed inline via TCP RST injection.