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CensorDB

About

How CensorDB is organized and how to use it.

CensorDB is an open database of blocked domains and IP prefixes. It documents how and where internet access is restricted, and turns those records into ready-to-use rule sets for circumvention tools. Entries are community-submitted and remain Pending until reviewed by an admin.

Developed and maintained by MahsaNet.

Data Categories

Lists

  • Block List: Targets blocked on the public internet.
  • Sanctioned List: Targets restricted due to sanctions-related limitations.
  • Domestic List: Targets reachable only inside a country (domestic/intranet).
  • Junk List: Ads, trackers, telemetry, and low-value domains (noise filter).

Block Methods

  • SNI: TLS Server Name Indication filtering.
  • DNS: DNS interference (NXDOMAIN/poisoning/sinkholing).
  • UDP: UDP disruption (drop/rate-limit).
  • IP: Direct IP address or prefix blocking.
  • HTTP: HTTP-layer filtering (e.g., middleboxes/content filters).

Operators (ISP)

  • ALL: Regulator-level blocking that affects all ISPs.
  • Specific operators indicate ISP-scoped blocking.
  • When ALL is selected, specific ISP flags are disabled.

Regions

  • IR is fully supported, with measured data and open submissions.
  • CN and RU are tracked and appear on the Statistics page, but are not yet open for submission.

Statistics

The Statistics page measures confirmed censorship per region. Figures come from a precomputed snapshot rather than live queries, so the page shows when it was last refreshed.

  • Blocked figures count confirmed blocks only; pending and not-blocked targets are excluded. Domestic, Sanctioned and Junk count every entry the list tracks, excluding unreviewed submissions.
  • The headline figure counts distinct domains and IP prefixes on record across all lists, so a site on several lists is counted once. The dataset tiles count memberships, so a multi-list site appears under each list and the tiles can add up to more than the distinct total.
  • Blocked, by ISP and by method count blocked targets carrying that flag. A target can carry several at once, so these rankings do not sum to the total.
  • The timeline shows how each dataset changes per month, week or day. For Block, up bars are sites confirmed blocked and down bars sites confirmed unblocked; for Domestic, Sanctioned and Junk, up bars are entries added to the list and down bars entries removed, excluding unreviewed submissions. It always spans a fixed recent window (at least a year of months, 26 weeks, 30 days), so quiet periods show as gaps rather than being skipped.

Searching

Use the Search page to query domains and IPs. Filters (methods/operators) apply to the Block List.

  • Results are ordered by the most recent updates (UTC).
  • Selecting multiple filters uses AND semantics.
  • Search runs server-side for accuracy and performance on large datasets.

Contributing

Submit new entries from the Search page: search first, and if the target is not found you can submit it there. Provide minimal context (where/when observed, operator, and method) to help verification.

  • New entries start as Pending until moderation.
  • Admins may add/remove flags to improve consistency.
  • Submit domains as hostnames (no http/https), and IPs as single IPs or prefixes.

Downloads

Use Downloads to get ready-to-use rule sets, rebuilt from the database every day.

  • .srs for sing-box.
  • .dat for Xray, v2ray and mihomo.
  • .mmdb for mihomo's geoip mode and other MaxMind readers. Being a geoip format, it carries IP prefixes only, no domains.
  • Files are grouped by country and list, with separate domain and prefix sets.

Notes

  • Times are shown in UTC.
  • Flag colors are for readability; hover for details where available.
  • Data changes over time; treat results as a point-in-time snapshot.