# ASN

An Autonomous System Number identifies one network that announces its own routes to the internet under a single routing policy.

Date: 2026-09-10

An Autonomous System Number identifies one network that announces its own routes to the internet under a single routing policy. Every address on the public internet belongs to exactly one at a time, and the AS is the closest thing to an answer to "whose network is this?".

## What Spaw answers

`asn` is the number, `org` the organisation that holds it, and `asn_type` the kind of network it is: hosting, ISP, business, education, government or similar. Three registry facts sit beside them — `registry`, `registry_country` and `allocated_at`, the date the block was allocated.

`asn_type` is what most policies actually want. A signup from a hosting AS is a different thing from a signup from a consumer ISP, and the type says which without anyone having to keep a list of cloud providers.

## What it does not say

An AS belongs to an operator, not to a person. On a hosting, VPN or relay network the country, the city and the organisation are the operator's, and the risk score's country comparisons are withheld for that reason. Nothing about an ASN identifies who is using the address.

Reference: https://spaw.co/glossary/asn