ASN / IP Lookup

Free bulk IP to ASN lookup in your browser. Organization, country and BGP prefix via Team Cymru DNS over Cloudflare DoH. Paste log lines; no API key.

Paste IPs or log lines and click Lookup ASN.

How to use it

  1. Paste IPv4/IPv6 addresses or whole firewall, WAF or access-log lines. Unique IPs are extracted automatically (browser cap: 50 per run).
  2. Each IP is looked up against Team Cymru's IP-to-ASN DNS (origin.asn.cymru.com / origin6) over Cloudflare DNS-over-HTTPS, then the ASN org name is fetched from AS<N>.asn.cymru.com.
  3. Results show ASN, organization, country (allocation CC), BGP prefix and registry. Private or unannounced addresses return no ASN.
  4. Need thousands of IPs or a CSV? Use the ASN IP Lookup actor on Apify.

Need thousands of IPs?

This browser tool caps sequential lookups so your tab stays responsive. For bulk log lines and CSV export, run the ASN IP Lookup actor on Apify (see the sample 8-IP task).

Related tools

Also try Cloud IP Lookup, DNS Lookup and MX Lookup.

FAQ

What is an ASN?

An Autonomous System Number identifies a network on the public Internet that shares a common routing policy. BGP announces IP prefixes from ASNs; knowing the ASN behind an IP helps attribute traffic to an ISP, cloud, or enterprise.

Where does the data come from?

Team Cymru publishes IP-to-ASN mappings over DNS. This page queries origin.asn.cymru.com (IPv4), origin6.asn.cymru.com (IPv6) and AS<N>.asn.cymru.com for the organization name, via Cloudflare DNS-over-HTTPS from your browser.

Why Cloudflare DoH?

Cloudflare's public resolver exposes a JSON DoH API (application/dns-json) that works from the browser without plugins. Lookups never pass through this site.

Why is country sometimes AU for 1.1.1.1?

Team Cymru returns the country of the prefix allocation (registry RIR data), not the anycast edge you reach. Cloudflare's 1.1.1.1 is allocated in AU but served from many countries.

How do I look up thousands of IPs?

This page caps sequential browser lookups at 50 so the tab stays usable. For bulk paste, CSV export and larger runs, use the ASN IP Lookup actor on Apify.

Want the full kit?

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