as-metadata (formerly asn-info)

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Explore AS metadata interactively at Lens by ipverse — search IP addresses, prefixes, and autonomous systems without downloading anything.

Overview

A comprehensive dataset of autonomous system metadata for all assigned ASNs (autonomous system numbers). Includes handle, organization name, and country code sourced from regional internet registries (RIR). Updated automatically when source data changes (checked daily).

Perfect for offline lookups, network analysis, threat intelligence, or any project where you need to map ASNs to organizations—no API rate limits, no external dependencies.

Update notes

• 2026-02-08: Added category (e.g. isp, hosting, government_admin) and networkRole (e.g. tier1_transit, stub) fields to AS metadata
• 2026-01-27: Added providerAsns field with list of upstream transit provider ASNs
• 2026-01-18: Breaking change: Replaced upstreams/downstreams with providers/customers/peers to accurately distinguish transit relationships from peering. Added degree and reach fields.
• 2026-01-08: Added registered field (RIR registration date), stats section (prefix and connectivity statistics), and moved lastAnnounced to top level.
• 2026-01-03: Repository renamed to as-metadata, CSV format changed to 4 columns (added country-code), JSON format added.
• 2025-08-03: Removed opinionated handle cleanup and removed quotes around descriptions to improve RFC4180 compliance
• 2023-09-03: Removed PEM certificates from description field

Available formats

JSON (~55-60 MB) and CSV (~6 MB)

JSON format:

[
  {
    "asn": 4711,
    "metadata": {
      "handle": "INTEC",
      "description": "INTEC Inc.",
      "countryCode": "JP",
      "country": "Japan",
      "origin": "authoritative",
      "category": "business",
      "networkRole": "stub",
      "registered": "1997-03-14T00:00:00Z"
    },
    "stats": {
      "ipv4": {
        "prefixes": 12,
        "prefixesAggregated": 8,
        "largestPrefix": 20
      },
      "ipv6": {
        "prefixes": 3,
        "prefixesAggregated": 2,
        "largestPrefix": 32
      },
      "connectivity": {
        "providers": 2,
        "providerAsns": [174, 3356],
        "customers": 5,
        "peers": 3,
        "degree": 10,
        "reach": 12
      }
    },
    "lastAnnounced": "2026-01-04T11:40:34.965574Z"
  },
  {
    "asn": 4712,
    "metadata": {
      "handle": "JT-NET",
      "description": "JAPAN TOBACCO INC.",
      "countryCode": "JP",
      "country": "Japan",
      "origin": "authoritative",
      "category": null,
      "networkRole": null,
      "registered": "1997-03-14T00:00:00Z"
    },
    "stats": null,
    "lastAnnounced": null
  }
]

CSV format:

asn,handle,description,country-code
0,IANA-RSVD-0,Internet Assigned Numbers Authority,US
1,LVLT-1,Level 3 Parent LLC,US
2,UDEL-DCN,University of Delaware,US
3,MIT-GATEWAYS,Massachusetts Institute of Technology,US
4,ISI-AS,University of Southern California,US
5,SYMBOLICS,WFA Group LLC,US
6,BULL-HN,ATOS IT Solutions and Services Inc.,US
7,DSTL,The Defence Science and Technology Laboratory,GB
.
.
.

Field descriptions

CSV fields

Field	Description
asn	Autonomous System Number
handle	Registry handle/identifier
description	Organization name or description
country-code	ISO 3166-1 alpha-2 country code (XX if unknown)

JSON fields

Field	Description
asn	Autonomous System Number
metadata.handle	Registry handle/identifier
metadata.description	Organization name or description
metadata.countryCode	ISO 3166-1 alpha-2 country code
metadata.country	Full country name
metadata.origin	Metadata source (see origin values)
metadata.category	AS classification; null if unclassified (see AS category and network role)
metadata.networkRole	Network role; null if unknown (see AS category and network role)
metadata.registered	RIR registration date (time normalized to 00:00:00Z); null for inferred ASNs
stats	Prefix and connectivity statistics; null for ASNs without route collector data
stats.ipv4.prefixes	Number of IPv4 prefixes announced
stats.ipv4.prefixesAggregated	Number of IPv4 prefixes after aggregation
stats.ipv4.largestPrefix	Largest IPv4 prefix announced (e.g. /13 — smaller number = larger block)
stats.ipv6.prefixes	Number of IPv6 prefixes announced
stats.ipv6.prefixesAggregated	Number of IPv6 prefixes after aggregation
stats.ipv6.largestPrefix	Largest IPv6 prefix announced (e.g. /29 — smaller number = larger block)
stats.connectivity.providers	Number of transit provider ASNs
stats.connectivity.providerAsns	List of transit provider ASNs (enables upstream quality analysis)
stats.connectivity.customers	Number of transit customer ASNs
stats.connectivity.peers	Number of settlement-free peer ASNs
stats.connectivity.degree	Total unique neighbor ASNs (providers + customers + peers)
stats.connectivity.reach	Customer cone size (ASNs reachable via customer relationships)
lastAnnounced	ISO 8601 timestamp when AS was last seen announcing prefixes; null if never seen

Origin values

Value	Description
authoritative	From authoritative source
inferred	Inferred from routing information; may be inaccurate
overlaid	Metadata overlay from as-overlay applied
none	No metadata available

AS category and network role

Category

Classifies the primary function of an autonomous system.

Value	Description
isp	Internet service provider (broadband, DSL, cable, fiber, mobile)
hosting	Hosting, cloud, or content provider
business	Enterprise or non-profit organization
education_research	Educational or research institution
government_admin	Government entity or public administration

null when unclassified.

Categorization is based on multiple signals and reflects the AS's primary function. It won't always be correct — many networks defy clean categorization (e.g. an ISP that also runs a hosting business, or a university with its own transit infrastructure). Take it as a useful default, not gospel. An overlay mechanism for user-supplied corrections may be added in the future.

Network role

Describes the connectivity role of an autonomous system based on BGP topology.

Value	Description
tier1_transit	Tier 1 transit provider with settlement-free global reach
major_transit	Major transit provider
midsize_transit	Mid-size transit provider
access_provider	Access or eyeball network
content_network	Content delivery network
stub	Stub AS with no transit customers

null when unknown.

Role assignment is based on BGP connectivity metrics with opinionated thresholds. Reasonable people may disagree on where exactly to draw the line between "major" and "mid-size" transit, or when a network stops being a stub.

How to use

Download the data directly:

JSON:

curl -O https://raw.githubusercontent.com/ipverse/as-metadata/master/as.json

CSV:

curl -O https://raw.githubusercontent.com/ipverse/as-metadata/master/as.csv

Or just clone the repo if that's your thing.

Quick example (Python):

import json
with open('as.json') as f:
    data = {entry['asn']: entry for entry in json.load(f)}
print(data[4711]['metadata']['description'])  # INTEC Inc.

Use cases

• Figure out who owns an ASN
• Enrich your IP intelligence tools
• Threat hunting and security research
• BGP analysis and network research
• Building dashboards or monitoring tools
• Offline lookups (no API rate limits to deal with)
• Pretty much anything where you need to map ASNs to operators

Related projects

• as-overlay: Autonomous system metadata overlays that supplement and enhance the authoritative data in this repository. When overlay data is applied, entries will have an origin value of overlaid in the JSON format.

Questions or issues?

Head over to the feedback repository if you have questions, issues, or suggestions.

License

This data is released under CC0 1.0 Universal.