FINDING · EVALUATION
Residential ISP vantage points detect 36% more blocking than academic networks: of 1,947,691 matched URL tests, 72,454 non-academic tests were classified as blocking versus 52,921 academic tests. Averaged across 10 countries, the Jaccard similarity between blocked-URL sets in academic vs. non-academic networks is 0.59, indicating substantial divergence.
From 2015-gill-characterizing — Characterizing Web Censorship Worldwide: Another Look at the OpenNet Initiative Data · §5.3, Fig. 12 · 2015 · Transactions on the Web
Implications
- Circumvention tool operators should instrument blocking detection from residential or mobile ISP probes rather than cloud or university VPS endpoints — academic vantage points will underestimate blocked surface area by roughly one-third.
- Deployment studies that measure whether a transport is blocked using PlanetLab or datacenter nodes will systematically miss blocks that only appear on residential paths, leading to false confidence in a protocol's reachability.
Tags
Extracted by claude-sonnet-4-6 — review before relying.