After a decade of ZMap-based measurement, the authors identify IPv6 scanning as an unresolved open problem: the vastly larger IPv6 address space makes exhaustive scanning infeasible, fundamentally changing the threat model for service discovery compared to IPv4.

A decade of ZMap-based studies has produced documented operational norms including blocklist hygiene (organizations can opt out of scans via ZBlocklist) and ethical rate-limiting practices. The same blocklist infrastructure that protects opt-out organizations also provides a model for reducing proxy infrastructure visibility.

Abstract — operational practices / ZBlocklist tool evaluation

Cloud-hosted services represent an open measurement problem for ZMap because IPs are shared, ephemeral, and behind CDN layers, making traditional IP-to-service attribution unreliable. The paper identifies reconciling scan-based observation with cloud infrastructure as a key challenge for the next decade.

Abstract — open problems evaluation

A decade of Internet-wide scanning practice has established that cloud-hosted services present a fundamental measurement ambiguity: IP ownership is ephemeral and shared, making per-IP findings unreliable and complicating the attribution of services to specific operators or censors.

Abstract (open problems) evaluation

IPv6 measurement remains an open problem for ZMap because the address space is too large for exhaustive single-packet enumeration, unlike IPv4. This asymmetry means IPv6-addressed infrastructure is structurally harder to enumerate via blocklisting.

Abstract — open problems evaluation

LZR, built on top of ZMap, can identify 99% of unexpected Internet services in five handshakes by acting as a shim between ZMap and ZGrab. This gives censors and researchers alike an efficient active-probing primitive to fingerprint proxy protocols at scale.

LZR tool description detection

ZMap can scan the entire public IPv4 address space on a single port in under 45 minutes on a gigabit connection; with a 10 GigE connection and PF_RING, the same scan completes in 5 minutes. This makes Internet-wide enumeration of proxy infrastructure operationally trivial for any well-resourced actor.

Project overview evaluation

ZMap can scan the entire public IPv4 address space on a single port in under 45 minutes on a 1 Gbps connection; with a 10 GigE connection and PF_RING, the full IPv4 address space scan completes in 5 minutes. This throughput enables near-real-time Internet-wide enumeration of any service listening on a given port.

ZMap tool description evaluation

'Resource Inaccessible' was the most frequently reported issue (61% of 119 submitted reports) during a month of naturalistic Tor Browser browsing, followed by CAPTCHAs (18%), Broken Content (17%), Other Issues (13%), and Timeouts (5%). These categories document the operational failure modes that degrade everyday Tor Browser usability beyond protocol-level censorship.

2026-micallef-reportor-facilitating-user §6.1, Figure 3 ip-blockingmeasurement-platform

The privacy properties of Tor Browser structurally preclude automated telemetry collection, creating a persistent blind spot for diagnosing user experience failures at scale. ReporTor demonstrates that anonymous voluntary in-situ reporting — transmitted over the Tor network and stored in a password-protected onion-service database — can substitute for telemetry: 119 reports over one month from five expert users sufficed to reproduce approximately half of reported issues exactly and identify root causes for most of the remainder.

2026-micallef-reportor-facilitating-user §1, §7.1 measurement-platform

The largest single source of censored domains in the GNL is MESA lab's SNI monitoring dataset (E21-SNI-Top200w.txt) containing 57,362 censored domains, and E21-SNI-Top120W-20221020.txt with 36,467 domains—totaling over 93K domains from network tap data alone for a single country (E21 = Ethiopia per InterSecLab attribution). A separate Xinjiang dataset (XJ-CUCC-SNI-Top200w.txt) contains 13,604 domains. These datasets "do not seem to come from popular domain lists, and instead appear to be gathered from network taps," confirming that Geedge builds censorship target lists directly from passive traffic observation.

2026-sheffey-geedge §4.2, Table 3 dpisni-blockingmeasurement-platform

Of 6,915,266 domains extracted from the 572 GiB Geedge Networks Leak (GNL), 298,955 censored domains (93.7% of all GNL-censored domains) appear in neither Tranco top-1M nor CitizenLab test lists. Measurements across China (Guangzhou/Nanjing), Myanmar, Pakistan, and Algeria confirmed censorship via DNS injection and SNI-based TLS connection termination. The GNL covers 25–62% of Tranco-censored domains across countries, showing substantial but incomplete overlap. This vendor-side ground truth reveals a censorship surface roughly two orders of magnitude larger than curated academic test lists.

2026-sheffey-geedge §4.1, Table 2 dpisni-blockingdns-poisoningmeasurement-platform

CensorAlert aggregates censorship signals from heterogeneous open sources — including OONI, Cloudflare Radar, NetBlocks, GitHub Issues of circumvention tools (Hysteria, Xray), Net4People BBS, NTC Party forum, Mastodon, X, Telegram channels, and arXiv — normalizing each item into a common schema preserving timestamp, source, raw data, and provenance with a link to the original content.

2026-zohaib-extended §2 (Data Sources) measurement-platform

Systematic measurement platforms (OONI, Censored Planet, Cloudflare Radar, NetBlocks) have inherent blind spots due to geographic coverage and protocol-specific test constraints; critical censorship discoveries — including GFW fully-encrypted protocol blocking and regional Chinese censorship — were first surfaced by user reports on forums and GitHub issue pages of circumvention tools, not by automated measurement infrastructure.

2026-zohaib-extended §1 measurement-platformfully-encrypted-detect