2016-aceto-analyzing
findings extracted from this paper
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Time-series analysis across five ISPs over six months reveals a near-universal stasis in January–February where blocklist changes were negligible for all ISPs, followed by significant fluctuations (e.g., a +20–35% swing in TCP unreachability between February and March for PTCL, Wateen, Qubee, and WiTribe). A ubiquitous drop in TCP-unreachability outcomes occurred December–January, suggesting a seasonal or policy-driven relaxation followed by re-tightening.
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DNS tampering in Pakistan takes at least two distinct sub-forms: WiTribe and Nayatel redirect blocked domains to explicit block-page IPs (DNS resolution returns a routable address that serves a block page), while PTCL returns both failing IPs and explicit block pages, indicating that PTCL applies DNS tampering without user notification in some cases (NXDOMAIN-like) and with a block page in others. Qubee passes DNS entirely and applies content-level HTTP tampering at roughly 80% of measurements for blocked URLs.
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Across five Pakistani ISPs measured over six months (Oct 2013–Mar 2014), censorship splits cleanly by ISP: WiTribe, PTCL, and Nayatel block via DNS tampering, while Wateen and Qubee block via HTTP content tampering. The two techniques do not overlap within a single ISP, demonstrating that Pakistan's censorship infrastructure is ISP-heterogeneous rather than centrally normalized.
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A university closed survey of 64 Pakistani users found that 51% evade censorship using VPNs (Hotspot Shield being the most prominent), 25% use web proxies, 17% use Tor/onion routing, and approximately 7.2% use CDNs, mirror sites, search-engine caches, or web-based DNS lookup services.