An Autonomous System Number identifies a network operator on the internet — an ISP, hosting company or large org that controls a block of IPs. Read what is an ASN.

Why does the ASN matter for fraud?

The AS organisation tells you whether an IP belongs to a residential ISP, a cloud host or a known abusive network — useful context alongside the abuse signals.

Can I look up an AS number directly?

This tool resolves an IP to its ASN. To explore an ASN's ranges programmatically, use the GeoQ API over the IPs you care about.

Free tool

ASN lookup

Resolve any IP address to its Autonomous System Number and organisation — the network operator behind the address — with datacenter and country context.

ASN lookup

GeoQ resolves an IP to its ASN and AS organisation. Enter an IP to see the network behind it.

response

{
  "asn": 15169,
  "as_org": "Google LLC",
  "example_ip": "8.8.8.8",
  "geo": {
    "country": "United States",
    "country_code": "US"
  },
  "signals": {
    "is_datacenter": true,
    "datacenter_provider": "gcp"
  }
}

What is an ASN?

An Autonomous System Number (ASN) identifies an independent network on the internet — an ISP, a hosting provider, or a large organisation that announces its own IP ranges via BGP. Every public IP belongs to exactly one AS at a time.

For fraud and abuse work, the AS organisation is gold: it tells you at a glance whether an IP is a residential consumer ISP, a cloud host (AWS, GCP, Azure…), or a network with a reputation for abuse. GeoQ returns the ASN and AS org on every /v1/check call, alongside the abuse signals.

Learn more in what is an ASN and why it matters for IP fraud. Other free tools: IP lookup and what is my IP. Ready to build? Free API key, no card.

ASN lookup

What is an ASN?

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