Find the network (AS number, owner, prefix and country) behind an IP address
Runs in your browser. Only the lookup you start is sent to cloudflare-dns.com or dns.google; nothing else leaves your device. Updated on 25 Oct 2026.An ASN lookup names the network that announces an IP address on the internet. For 8.8.8.8 the answer is AS15169, Google LLC, prefix 8.8.8.0/24, registered with ARIN. The data comes from Team Cymru's free IP to ASN mapping, asked through a public DNS resolver from your browser.
Type an IP address or an AS number, such as 8.8.8.8 or AS15169, in IP address or AS number.
Press Look up; the question goes through the chosen resolver to Team Cymru.
Read the AS, Network name, Country, Registry and Allocated columns.
Press Copy result to copy the network details as text.
The internet is made of tens of thousands of autonomous systems: networks such as an ISP, a cloud provider or a university, each with its own AS number, that tell each other which address blocks they carry using BGP. This ASN lookup takes an IP address and tells you which of them announces it, or takes an AS number and tells you who it belongs to.
For an IP, the page shows the origin AS, the BGP prefix that covers the address, the country and regional registry (ARIN, RIPE NCC, APNIC, LACNIC or AFRINIC) and the allocation date, then the AS's registered name. When more than one prefix covers the address, the most specific one is listed first, because that is the route traffic follows. When two networks announce the same prefix, the page says so: that can be deliberate, or a sign of a route leak.
The answers come from Team Cymru's IP to ASN mapping service, which publishes this routing data as DNS TXT records. For 8.8.8.8 the page asks for the TXT record at 8.8.8.8.origin.asn.cymru.com and gets back "15169 | 8.8.8.0/24 | US | arin | 2023-12-28", then asks AS15169.asn.cymru.com for the name. Both questions go through the public resolver you choose, Cloudflare or Google, so the IP or AS number you type is sent to that resolver and, through it, to Team Cymru's servers; nothing else leaves your device.
Private and reserved addresses, such as 192.168.x.x or 10.x.x.x, are recognised on the page and never sent anywhere: no network announces them. The tool does not give a street location or the person using an address. The country is where the block was registered, which is often not where the device is.
An autonomous system number identifies one network on the internet, such as an ISP, a cloud provider or a large company, that announces its own blocks of addresses to other networks using BGP. Google is AS15169 and Cloudflare is AS13335. Regional registries such as ARIN and RIPE NCC assign the numbers.
Type the IP address. The page asks Team Cymru's routing data which AS announces it, then asks for that AS's registered name. The answer shows the AS number, the organisation, the BGP prefix covering the address, the registry and the country it was allocated in.
From Team Cymru's free IP to ASN mapping service, which publishes BGP routing data as DNS TXT records at origin.asn.cymru.com, origin6.asn.cymru.com and asn.cymru.com. The page reads those records through a public DNS resolver, so the answer is only as current as Team Cymru's data.
The IP address, reversed into a DNS name, or the AS number goes to the resolver you choose, Cloudflare or Google, which forwards the question to Team Cymru's name servers. Nothing else leaves your device, and private addresses such as 192.168.1.1 are answered on the page without any request.
Only roughly. The country shown is where the address block was registered, which for a cloud or mobile network is often a different country from the device using it. An ASN lookup names the network, never a street address or the person behind a connection.
No network is announcing it in the global routing table. Private ranges such as 10.0.0.0/8 and 192.168.0.0/16, documentation ranges, and blocks that are allocated but unused all have no origin AS. A block that started being announced only recently may also be missing until Team Cymru's data catches up.
Still stuck? Ask about ASN Lookup and anybody who knows can answer. No account needed.
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Also works as: IP Address Lookup.