ASN directory
82,180 networks, searchable by operator or number.
The 5,000 largest, by type
An autonomous system number (ASN) is one organisation's piece of the routing table: a set of IP ranges announced to the rest of the internet under a single number, like AS15169 for Google or AS7922 for Comcast. Use this ASN directory to look up any network by number or operator name. Every address belongs to exactly one of them, so the ASN is the shortest honest answer to "who runs this address?". It is also the first thing that separates a customer at home from a server in a rack, because the two sit on different networks run by different companies for different reasons.
Ranked by how many IPv4 addresses the operator announces, which is a better measure of reach than the prefix count beside it: a network can announce forty thousand small prefixes and still be smaller than one that announces a handful of large ones.
| ASN | Organisation | Type | Prefixes | IPv4 addresses |
|---|---|---|---|---|
| AS749 | United States Department of Defense (DoD) | Unclassified | 2,828 | 222,065,664 |
| AS16509 | Amazon.com, Inc. | Hosting and cloud | 7,634 | 157,304,832 |
| AS4134 | Chinanet | Consumer ISP | 16,035 | 99,129,321 |
| AS7018 | AT&T Enterprises, LLC | Consumer ISP | 72,376 | 89,925,389 |
| AS8075 | Microsoft Corporation | Hosting and cloud | 1,392 | 80,749,312 |
| AS7922 | Comcast Cable Communications, LLC | Consumer ISP | 115,974 | 67,781,383 |
| AS4837 | CHINA UNICOM China169 Backbone | Consumer ISP | 2,498 | 57,243,392 |
| AS4766 | Korea Telecom | Consumer ISP | 5,412 | 46,380,282 |
| AS701 | Verizon Business | Consumer ISP | 27,671 | 40,591,280 |
| AS17676 | SoftBank Corp. | Consumer ISP | 242 | 38,445,056 |
| AS3320 | Deutsche Telekom AG | Consumer ISP | 1,206 | 34,156,798 |
| AS721 | United States Department of Defense (DoD) | Unclassified | 5,381 | 29,473,792 |
| AS4713 | NTT DOCOMO BUSINESS,Inc. | Consumer ISP | 293 | 28,624,128 |
| AS3356 | Level 3 Parent, LLC | Unclassified | 4,597 | 27,409,406 |
| AS174 | Cogent Communications, LLC | Unclassified | 9,440 | 24,695,286 |
| AS396982 | Google LLC | Hosting and cloud | 711 | 21,975,808 |
| AS14618 | Amazon.com, Inc. | Hosting and cloud | 1,451 | 21,588,224 |
| AS3215 | Orange | Consumer ISP | 868 | 20,083,195 |
| AS3269 | TIM | Consumer ISP | 328 | 19,828,223 |
| AS2516 | KDDI CORPORATION | Mobile carrier | 452 | 18,072,575 |
Showing 20 of the 5,000 networks in the committed snapshot. Search above to reach the rest.
API
No key, no signup. The same index answers a search or a single network, and the JSON is what these pages are rendered from.
curl https://ipscanner.io/v1/asn/directory/AS15169 curl "https://ipscanner.io/v1/asn/directory?q=comcast&limit=20" curl "https://ipscanner.io/v1/asn/directory?top=200&by=addresses"
The number identifies who announces an address, which is a fact about ownership. It is strong evidence about what the address is used for and weak evidence about who is sitting behind it. A hosting ASN means the address is in somebody's infrastructure, so a request from it is a server rather than a person on a laptop, but plenty of legitimate traffic comes from servers. A consumer ISP means the opposite, and a VPN operator means the traffic was deliberately routed to hide where it came from.
Where an ASN cannot help at all is the residential proxy: an address that belongs to a real consumer ISP and is rented out anyway. That needs behaviour, not ownership, which is what the IP Detection API adds on top of the data in this directory.
One call returns the ASN, the operator and the network type (hosting, VPN, mobile, ISP) for any address. Free for 30,000 requests a month, no card.