Hosting Concentration and RPKI Route-Origin Validation Status of All Japanese Municipal Government Websites (October 2026 snapshot)

Otoi, Nobuo

doi:10.5281/zenodo.23692415

If many municipal websites sit in the same few networks, one network problem or one unprotected prefix affects many local governments at once. This dataset records, for the official website of every one of Japan's 1,741 basic municipalities, where it is hosted and whether the route to it is protected by RPKI, from one day's public measurements, so that anyone can repeat it.

What is measured

For every municipal website host the dataset records all IPv4 addresses returned by DNS, the covering BGP prefix, the origin autonomous system with its name and registration country, the RPKI route-origin validation state (RFC 6811: valid, invalid or not found) of each prefix–origin pair against a dated set of Validated ROA Payloads (VRPs), and the presence of IPv6 (AAAA) records and DNSSEC validation. Prefecture-level concentration indices (largest-provider share and the Herfindahl–Hirschman index) and a nationwide origin-AS summary are derived from the same rows.

No vulnerability probing was performed. The inputs are DNS queries, one bulk whois lookup and a comparison with a public VRP file, all collected on 27 Oct 2026.

How it can be repeated

The record contains the primary table (1,741 rows), the two derived tables, the source population file (47 prefectures and 1,916 municipality entries, wards included), the raw DNS and whois answers, the VRP provenance (build time, ROA count, content hashes) and a single script that rebuilds every table from the raw files or re-measures from scratch. The 112 MB VRP file is not shipped; its URL and SHA-256 are recorded and the script downloads the current one on request. A codebook for every column is in the README.

Links

Dataset

Cite as

Nobuo Otoi (ba-cybersecurity.com). Hosting Concentration and RPKI Route-Origin Validation Status of All Japanese Municipal Government Websites (October 2026 snapshot). 2026. https://doi.org/10.5281/zenodo.23692415.

@misc{otoi2026jpmuni,
  author       = {Otoi, Nobuo},
  title        = {Hosting Concentration and RPKI Route-Origin Validation Status of All Japanese Municipal Government Websites (October 2026 snapshot)},
  year         = {2026},
  doi          = {10.5281/zenodo.23692415},
  publisher    = {Zenodo},
  howpublished = {\url{https://ba-cybersecurity.com/research/jp-municipal-hosting-rpki/}},
  note         = {Dataset, version 1.0. Data CC BY 4.0, scripts MIT}
}

Measured and published 27 Oct 2026 · This page: updated 7 Nov 2026 · Permanent address: https://ba-cybersecurity.com/research/jp-municipal-hosting-rpki/

ba-cybersecurity.comResearch by Nobuo Otoi